7.5: Focussing in on Linear A
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Returning now to LA administration, it seems that a link exists between the architectural context of deposits and their composition and function (Schoep 2002 b : 25). Although few documents have been found in primary contexts, it is nevertheless possible to identify three commonly occurring groupings (Schoep 1995: 57). “Full combination deposits” always contain single-hole hanging nodules, alongside tablets and other sealings; as the single-hole nodules are postulated to hang from the highest-level records, on perishable materials, these deposits may be ‘archives’ (Schoep 1995: 61). This seems to be supported by their location, in central buildings (including Malia Palace, Zakros House A, and the ‘villa’ at Ayia Triada), usually on an upper floor in residential quarters, clearly separated from storage or work areas, and by their association with valuable objects (Schoep 1995: 61, table 3, 62). ‘Single type deposits’ consist of direct object sealings, tablets or noduli, and most seem to be in the location in which they functioned; the direct object sealings are found in magazines suitable for bulk storage, as at Monastiraki, while tablet or noduli deposits can also occur in smaller-scale storage rooms, for example, Houses I, Chania or FG, Gournia (Schoep 1995: 62–63). “Limited combination deposits” fall somewhere in between; deposits from the ‘villa’ at Ayia Triada and Zakros Palace contain tablets and sealed documents, in workshop or storage areas, while other deposits contain only sealings, such as the flat-based nodules and roundels from Phaistos (Schoep 1995: 63). One of the Ayia Triada deposits, tablet HT 24 and 45 uninscribed noduli, found in an area used for storage, points towards these being active, working (and possibly linked) documents. All noduli are nearly identical and impressed with the same seal, their uniformity indicating they had been prepared on the spot for distribution, and as the tablet records 47 units of something, it is tantalising to suppose the noduli are ‘receipts’, prepared in advance of the tablet’s expected delivery (Krzyszkowska 2005: 162; Schoep 1995: 63).
The distribution of documents within settlements has been taken to indicate three levels of administration, central, decentralised and private; significantly, roundels and single- and two-hole hanging nodules are not found in private administrative contexts, suggesting their use is a prerogative of central administration (Schoep 1996: 80). The absence of single-hole nodules could suggest that ‘archives’ on perishable materials are not kept in private houses (Schoep 1996: 80).
This prompts the question of how visible each document form would be? Tablets and noduli are the most widespread documents, occurring on their own, in private buildings as well as those connected with the central administration (Schoep 1996: 79), so are potentially more visible than documents kept in central building ‘archives’, which are stored, together with precious objects, upstairs in residential quarters (Schoep 1995: 62). However, all of these are, broadly speaking, ‘elite’ contexts, the central buildings as the seats of some sort of regional power, and the private dwellings marked out by their architectural elaboration and spatial organisation (Schoep 1996: 78–79). As such, it is likely that access to the documents within these buildings is in general restricted to those living or working there, and, as Michailidou suggests, “ordinary people presumably did not come into contact with the typical ‘document’ of a tablet” (Michailidou 2000–2001: 8).
There are two possible exceptions to this, however: the roundel and the ‘active’ nodulus (that is, when it is being used, prior to archiving). According to Weingarten’s (1990 a : 19-20) reconstruction, noduli are mobile and transferable documents, being carried by travellers as a form of identification, or to exchange for goods and services, or acting as dockets to claim ‘payment’ for work done. Thus, they would be visible to a wide range of people, including some, such as labourers or those offering lodgings, who are unlikely to be creators of documents themselves; significantly, they use seal impressions rather than script to convey the necessary information. While some roundels, receipts held by the central administration for goods it issues, are created by a seal-user and scribe who are both employed within the administration, others are not (Hallager 1996: 115), suggesting that the seal-user came into the central building from outside. While Hallager (1996: 120) interprets the number of seal impressions on the roundel as a device to protect the individual from fraud on the part of the administrator, an alternative interpretation is that it enables a potentially illiterate seal-user to confirm the quantity of goods received. It does seem likely, then, that ‘ordinary people’, in the course of interacting with the central administration or local elites, would use roundels and noduli rather than other document forms, and moreover, that these two are geared towards use by those who cannot necessarily write, or read much beyond the limited range of ideograms used. Having said that, if the seal-user is impressing a roundel to verify receipt of a certain quantity of goods, this would require some numerical literacy.
Interestingly, given our tendency to focus on administrative documents, it is also possible that some non-administrative inscribed objects might have equal, potentially greater, visibility to the general population. The Inscribed Stone Vessels (ISVs), which have an inscription carved on the top face or sides, are probably the most visible to a wide sector of society, being found amongst the offerings at open-air peak sanctuaries, as well as in domestic contexts (Schoep 1994: 11). There are far fewer ISVs than non-inscribed examples — 4% of the stone vessels in the peak sanctuary of Iouktas have inscriptions (Karetsou et al. 1985: 102) — but they are found mixed together with other votive objects, so are presumably involved in the same rituals (Schoep 1994: 19). Inscriptions occur on crudely carved, simple stone vessels as well as better-made ones, and although a few examples from Iouktas may have been made specifically to be inscribed, on most the inscription is dependent on the shape of the vessel (Schoep 1994: 19, n. 113). The two inscribed hair or dress-pins from tholos tombs at Mavro Spelio and Platanos, on the other hand, may have been shaped deliberately to provide a surface suitable for engraving (Alexiou and Brice 1976: 20; see also Flouda, this volume).
Unlike the text on the administrative documents, which are ‘interrupted’ by ideograms and numerals, most non-administrative inscriptions are continuous and written to be aesthetically pleasing, but their function is uncertain beyond what they contribute to the intrinsic meaning of the object, either in the context of elite conspicuous consumption, and/or ritual activity (Michailidou 2000–2001: 18; Schoep 2002 a : 14, 17). This could be another example, as with the ISJs above, of adding writing to make an artefact into a textual document (Knappett 2008 a : 152), in the case of the inscribed pins or ring, a text perhaps to be ‘read’ with the fingers as you put the object on, or, if the support is the significant component, of giving an otherwise ephemeral prayer or dedication a solid and permanent form.
The extent to which these patterns of administration map onto political organisation is uncertain. The appearance of matching impressions from a small number of metal signet rings on flat-based nodules at Thera in Late Minoan IA and various Cretan sites in Late Minoan IB has been taken as evidence that Knossos is the paramount centre at this time, issuing official documents to subordinate centres, sealed by precious-metal seals engraved with propagandistic imagery (Hallager 1996: 207–209; Krzyszkowska 2005: 189–191). Several of the assumptions underpinning this can be questioned though: that high-quality gold rings could only be made at Knossos, for example, or that the iconography is exclusively Knossian, and these documents and their sealings are perhaps better regarded as evidence for a particular sort of communication between elite groups within and beyond Crete (Krzyszkowska 2005: 189–191).
The lack of standardisation visible in LA use, with different shapes and formats of document type, suggests, rather, that local administrators are acting independently, and this could reasonably be a reflection of regional centres managing their own affairs, whilst communicating inter- regionally using the flat-based nodules (Schoep 1999 b : 220). Political or ideological control does not always imply economic or administrative control, of course, but if a single centre is controlling most of Crete at this point, its power is insufficiently centralised to influence local administration procedures (Schoep 1999 b : 220).
In reviewing the evidence for LA use in the Second Palace Period, one gets an impression of a widespread use of writing on several media, and for several purposes, with either the writing support being manipulated to add meaning to the text (as with the clay administrative documents) or the other way around (as might be the case with some of the non-administrative objects). Although examples of writing are relatively widespread in the landscape, this need not necessarily equate to widespread literacy, not least because it seems likely that writing is principally an elite activity, and furthermore, that restricted contexts of use possibly mean that ordinary, non-writing, people might well interact with only a single kind, or a small range, of documents, creating a sort of sub-category of literacy, where understanding part of a text’s meaning derives largely from the form of its support and context of use.


2.3: Conservation and Naturalism
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- Jennifer Hasty, David G. Lewis, & Marjorie M. Snipes
- OpenStax
Learning Objectives
By the end of this section, you will be able to:
- Describe conservation efforts undertaken in the United States in the 19th century.
- Define salvage anthropology and describe its origins and methods.
- Provide an example of an anthropologist who used their research to help the people they were studying.
- Explain why museums can be said to have created exhibits reflecting limited interpretations and describe efforts to correct this limitation.
Early Efforts
The conservation movement began in the 19th century as people in Europe and America began to realize that human settlement and the exploitation of the world’s natural resources had led to the destruction or endangerment of numerous animals, plants, and significant environments. Efforts began in the 1860s to understand and protect the remaining natural landscapes and habitats. These efforts were partly motivated by concern for wildlife and natural areas. However, also significant were the concerns of sporting organizations and recreationists. The primary aim of early conservation efforts was to preserve significant natural ecosystems for parks or wilderness areas so that sportspeople and outdoor enthusiasts would have places to hunt, fish, and explore. Many areas preserved by these early efforts are still protected today, such as Yellowstone and Yosemite National Parks in the United States.
An element of this early period of conservation was the effort to collect specimens for display in natural history museums. This collection effort was part of a movement known as naturalism , which seeks to understand the world and the laws that govern it by direct observation of nature. The late 19th and early 20th centuries saw a marked growth in naturalist collections worldwide as many cities and nations sought to establish and fill their own natural history museums. These collections have been particularly useful to zooarchaeologists and archaeobotanists, who use specimen collections of mammals, birds, fish, and plants to identify natural objects and animal remains found at human burial sites. Many archaeology labs have collections of animal skeletons for comparative anatomy, analysis, and identification (see Figure 2.5).
In addition to animal specimens, Native American baskets and other Indigenous art objects were collected and placed in natural history museums. When visiting the Auckland Museum in Auckland, New Zealand, visitors today encounter two large totem poles in the foyer. Northwest Coast totem poles are common in most older museums throughout the world. These totem poles were gathered from America’s Northwest Coast in the late 19th and early 20th centuries as part of the worldwide conservation and naturalism movement. Most museums sought to purchase such artifacts, but in some cases, artifacts were stolen when Indigenous owners were unwilling to sell them. Many natural history museums also established dioramas depicting both Indigenous peoples and animals in their “natural” world. The practice of installing dioramas of Indigenous people is now heavily criticized because of the implication that Indigenous peoples are akin to animals and plants. Many museums have stopped this practice and have even dropped the phrase natural history from their names. However, the Smithsonian Institution’s National Museum of Natural History in Washington, DC, and the American Museum of Natural History in New York both maintain the designation and still display dioramas of Indigenous peoples.
Salvage Anthropology
Connected to the collecting of Indigenous artifacts is a practice known as salvage anthropology . Salvage anthropology was an effort to collect the material culture of Indigenous peoples in the United States and other parts of the world who were believed to be going extinct in the later 19th century. During this period, many anthropologists dedicated themselves to collecting material objects, stories, language lists, and ethnographies from tribal peoples worldwide. Many collections were made through legitimate means, such as purchasing objects or sitting down with collaborators (called informants in older anthropological vernacular) to record traditional stories, but some collecting involved the theft of tribal cultural items or purchases from intermediary traders.
Many of these anthropologists were hired by the Bureau of American Ethnology (BAE), a division of the Smithsonian Institution, and spent considerable time living with Native peoples on the reservations that were by then home to most Native Americans. Language was a special research focus for linguists and anthropologists, as many Native languages were rapidly going extinct. Through analysis of language, an anthropologist can understand the meaning of words and their context as well as gain a sense of a culture’s philosophy and worldviews.
Anthropologists were not paid well to do this work for the BAE. Some began supplementing their income by buying cultural objects at a low cost from the people they studied and selling those objects at a much higher rate to museums. This practice is now acknowledged as unethical and exploitative. The anthropological research of this period has also been criticized for focusing solely on cultural knowledge while ignoring the hardships faced by the culture. For example, few anthropologists chose to help their subjects address the circumstances of living in poverty on the reservations.
Leonard J. Frachtenberg was an anthropologist working during the salvage anthropology period who did take action to help the people he was studying. Around the turn of the 20th century, Frachtenberg was conducting research to collect the languages of the people living on the Siletz Reservation, in Lincoln County, on Oregon’s coast. He worked extensively with collaborators from the Coos, Coquille, Lower Umpqua, and Alsea tribes—some of whom were living at the Siletz Reservation and some who had returned to their native lands—and published a series of oral histories based on his research. He also helped the tribes locate lost unratified treaties from the 1850s and use those treaties to successfully sue the federal government. In the treaties, the government had promised to pay the Indigenous peoples of Oregon’s coast for their ancestral land if they peacefully relocated to the Siletz Reservation. The people upheld their part of the bargain, but they never received any payment. Frachtenberg helped a Coquille man named George Wasson travel to Washington, DC, and locate copies of the treaties in the National Archives. In 1908, the tribes began the process of successfully suing the federal government for payment for their lands. This process took some 40 years to complete for many tribes, and not all tribes have been fairly paid to this day.
Museum Collections
Most of the materials collected by anthropologists during the period of salvage anthropology ended up in museums and university archives. Many natural history museums now display large dioramas featuring the material objects of numerous tribes. Museum research libraries house extensive collections of manuscripts and ethnographies. Archaeologists have contributed to these collections as well; many museums contain large collections of human remains. Indigenous peoples have criticized these collections, especially the gathering of human remains, which is seen as sacrilegious. Today, there are millions of sets of human remains (some full skeletons, but most single bones) in museum repositories that have never been studied and perhaps never will be.
Anthropologists spent so much of their time in the early period collecting that they had little time to study or analyze what they found. Many collections were put in storage after the anthropologists who had gathered them moved on to a new project or passed away. There are currently millions of material artifacts and ethnographic manuscripts that have never been fully studied. These archived materials offer research opportunities for anthropologists as well as for Indigenous peoples, who are making use of these collections to help recover parts of their cultures that were lost due to the assimilation policies of the past 200 years.
One person who has taken advantage of these archives is linguistic anthropologist Henry Zenk. Zenk has spent years studying the languages and cultures of the tribes of western Oregon, specifically the Chinook, Kalapuya, and Molalla tribes. He conducted research with the Grand Ronde tribe in the 1970s and 1980s and became a proficient speaker of Chinuk Wawa, a trade language spoken by tribes from southern Alaska to northern California and as far east as Montana. He has taught the language at the Grand Ronde Reservation for nearly 30 years. He is also one of the experts on the Kalapuya languages, spoken by the Kalapuya tribes of the Willamette and Umpqua Valleys, and in 2013, he began a project to translate the Melville Jacobs Kalapuya notebooks.
Melville Jacobs was an anthropologist from the University of Washington who studied the languages of the Northwest Coast from 1928 until his death in 1971. He filled more than 100 field notebooks with information on the languages of the peoples of western Oregon, with a special focus on Kalapuya. Jacobs published a book of Kalapuya oral histories in 1945, Kalapuya Texts . He also worked with Kalapuya speaker John Hudson to translate numerous texts prepared by earlier anthropologists Leonard Frachtenberg and Albert Gatschet. Jacobs and Hudson were able to translate several of these previously gathered texts, but many remained untranslated when Hudson died in 1953. Zenk, along with colleague Jedd Schrock, spent many years first learning Kalapuya and then translating a set of the Jacobs notebooks that recorded the knowledge and history of a Kalapuya man named Louis Kenoyer. In 2017, Zenk and Schrock published My Life, by Louis Kenoyer: Reminiscences of a Grand Ronde Reservation Childhood . Zenk and Schrock’s work is a fine example of the research possibilities offered by the existing work of previous anthropologists.
Zenk worked closely with the Grand Ronde tribe on this project and endeavored to make sure that the translation of Kenoyer’s story would benefit the people of the tribe to help them to better understand their own history. His research and work with members of the Grand Ronde tribe spanned 50 years, beginning with his PhD project, which involved extensive work with Grand Ronde members, who at the time were not a federally recognized tribe. In the 1990s, Zenk began working with the tribe to teach Chinuk Wawa to tribal members. The tribe today has an extensive language immersion project to teach the language to young people. Zenk has been a consistent influence, serving as advisor, teacher, master-apprentice instructor, and researcher. Zenk’s work has helped the tribe recover parts of its culture and history that had been lost for many decades.
Profiles in Anthropology
Albert Gatschet (1832–1907)
Personal History: Albert Gatschet was a Swiss philologist and ethnologist who emigrated to the United States in 1868. He had a great interest in linguistics and Native American languages, and he gained attention in 1872 for his comparative analysis of 16 southeastern tribal vocabularies, which opened up new areas of research in linguistics. In 1877, he was hired to work on the Geographical and Geological Survey of the Rocky Mountain Region as an ethnologist. He also collected many notebooks of languages from Native peoples in California and Oregon. He is most noted for his studies of the languages of the southeastern tribes and his ethnography of the Klamath Tribes of Oregon.
Gatschet was fluent in numerous languages and published in English, French, and German in the United States and Europe during his career. He also became quite fluent in numerous Native languages. His first large work was Orts-etymologische Forschungen aus der Schweiz (Etymological research on place names from Switzerland, 1865–1867), a study of Swiss place names that is still the standard authority today.
Area of Anthropology: Philology, ethnology, linguistics
Accomplishments in the Field : One of Gatschet’s most significant analyses was of the southeastern tribal languages, principally the Timucua language of northern Florida. Based on analysis of the notes of the Catholic priest Father Pareja, who had collected language texts from the Timucua people in 1612–1614, Gatschet determined that Timucua was a distinct language group that had gone extinct. Gatschet also examined the Catawba language of South Carolina, concluding that it was related to the Siouan languages of the western Great Plains. From 1881 to 1885, Gatschet worked in Louisiana, discovering two new languages and completing ethnographic descriptions of the southern tribes. In 1886, he found the last speakers of the Biloxi and Tunica languages and related them to the Siouan languages as well. He published his studies of the Gulf tribes in the two-volume work A Migration Legend of the Creek Indians (1884, 1888).
In 1877 and 1878, Gatschet spent time among the tribes of the Grand Ronde Reservation in Oregon. He collected some of the first professional field notes on the Kalapuya, Molala, and Shasta languages from some of the last speakers, and he published and made notes about the Kalapuya mounds. Upon leaving the reservation, he spent time researching the traditions of the Tualatin Kalapuya people in their traditional lands in the Tualatin Valley. He then went to the Klamath Reservation, where he collected field notes on the Klamath language. He worked his field notes into a two-part work, The Klamath Indians of Southwestern Oregon (1890), volume 2 of the US Department of the Interior’s Contributions to North American Ethnology .
Gatschet was commissioned by the Bureau of American Ethnology (BAE) in 1891 to investigate the Algonquian people of the United States and Canada, a study he never fully completed. Illness forced him to retire, but near his death, he remained engaged in studies of Chinese languages.
After his death, his wife, Louise Horner Gatschet, sold his field notes to the BAE. She was also hired by the BAE to help translate much of his work. Gatschet’s letters mention his wife being with him throughout his travels; she likely contributed in numerous ways to his field studies.
Importance of His Work : Gatschet was one of the first professional anthropologists to visit many tribes and was able to collect ethnographies and narratives from peoples who were gone within the next decade. He analyzed language families in the field and provided early frameworks of connected languages. Gatschet’s work is fundamental to the study of the languages of western Oregon and the southeast Gulf area of the United States. His professional work, which applied rigorous methods to collect Native languages, predates much of the work of Franz Boas, who is credited with implementing scientific methods in the study of human societies.
Interpretation and Voice
There is increasing acknowledgement of the role of interpretation in the study of the human past. Although ideally grounded in well-conducted research and the best evidence available at the time, all conclusions about what might have been are based on the interpretations proposed by the authors of history. The backgrounds and viewpoints of those conducting research and publicizing findings play a significant role in the conclusions they reach and share with other scholars. Interpretation and perspective are affected by many factors, including racial category, nationality, religious beliefs, social status, political affiliation, ambitions, and education. For many years, anthropological studies were almost always conducted by White, male scholars who grew up in the Northern Hemisphere and were educated in the same system. These common backgrounds represent a significant interpretive bias.
After being accessioned into museums, many collections of cultural artifacts have not been altered in more than 100 years. When these material objects were initially placed on display, choices about their arrangement and the written descriptions that accompanied them were made by museum curators. Most of these curators did not reach out to the originators of the artifacts or their descendants for input, and many exhibits do not accurately depict or describe the objects on display. Museum exhibits have been found to contain inaccurate information about objects’ material composition, makers, tribal cultures, collection sites, and proper use. Many other display objects are lacking this information altogether.
Several museums are now seeking the help of Native people to better understand and more accurately tell the story of their collections. These Native perspectives are correcting misconceptions about the meaning and context of cultural artifacts and providing correct information about basic things such as the materials and processes used in the objects’ production. Native input is also guiding museums in making choices about how objects are arranged and displayed. This input has been invaluable in helping museums more accurately tell the stories and display the context of the peoples who originally created the objects on display.


10.E: Cell Reproduction (Exercises)
This page is a draft and is under active development.
10.1: Cell Division
The continuity of life from one cell to another has its foundation in the reproduction of cells by way of the cell cycle. The cell cycle is an orderly sequence of events that describes the stages of a cell’s life from the division of a single parent cell to the production of two new daughter cells. The mechanisms involved in the cell cycle are highly regulated.
Review Questions
A diploid cell has_______ the number of chromosomes as a haploid cell.
- one-fourth
- half
- twice
- four times
- Answer
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C
An organism’s traits are determined by the specific combination of inherited _____.
- cells.
- genes.
- proteins.
- chromatids.
- Answer
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B
The first level of DNA organization in a eukaryotic cell is maintained by which molecule?
- cohesin
- condensin
- chromatin
- histone
- Answer
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D
Identical copies of chromatin held together by cohesin at the centromere are called _____.
- histones.
- nucleosomes.
- chromatin.
- sister chromatids.
- Answer
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D
Free Response
Compare and contrast a human somatic cell to a human gamete.
- Answer
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Human somatic cells have 46 chromosomes: 22 pairs and 2 sex chromosomes that may or may not form a pair. This is the 2 n or diploid condition. Human gametes have 23 chromosomes, one each of 23 unique chromosomes, one of which is a sex chromosome. This is the n or haploid condition.
What is the relationship between a genome, chromosomes, and genes?
- Answer
-
The genome consists of the sum total of an organism’s chromosomes. Each chromosome contains hundreds and sometimes thousands of genes, segments of DNA that code for a polypeptide or RNA, and a large amount of DNA with no known function.
 Explain how chromosomes can fit inside a eukaryotic nucleus.
- Answer
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The DNA double helix is wrapped around histone proteins to form structures called nucleosomes. Nucleosomes and the linker DNA in between them are coiled into a 30-nm fiber. During cell division, chromatin is further condensed by packing proteins.
10.2: The Cell Cycle
The cell cycle is an ordered series of events involving cell growth and cell division that produces two new daughter cells. Cells on the path to cell division proceed through a series of precisely timed and carefully regulated stages of growth, DNA replication, and division that produces two identical (clone) cells. The cell cycle has two major phases: interphase and the mitotic phase.
Review Questions
Chromosomes are duplicated during what stage of the cell cycle?
- G 1 phase
- S phase
- prophase
- prometaphase
- Answer
-
B
Which of the following events does not occur during some stages of interphase?
- DNA duplication
- organelle duplication
- increase in cell size
- separation of sister chromatids
- Answer
-
D
The mitotic spindles arise from which cell structure?
- centromere
- centrosome
- kinetochore
- cleavage furrow
- Answer
-
B
Attachment of the mitotic spindle fibers to the kinetochores is a characteristic of which stage of mitosis?
- prophase
- prometaphase
- metaphase
- anaphase
- Answer
-
B
Unpacking of chromosomes and the formation of a new nuclear envelope is a characteristic of which stage of mitosis?
- prometaphase
- metaphase
- anaphase
- telophase
- Answer
-
D
Separation of the sister chromatids is a characteristic of which stage of mitosis?
- prometaphase
- metaphase
- anaphase
- telophase
- Answer
-
C
The chromosomes become visible under a light microscope during which stage of mitosis?
- prophase
- prometaphase
- metaphase
- anaphase
- Answer
-
A
The fusing of Golgi vesicles at the metaphase plate of dividing plant cells forms what structure?
- cell plate
- actin ring
- cleavage furrow
- mitotic spindle
- Answer
-
A
Free Response
Briefly describe the events that occur in each phase of interphase.
- Answer
-
During G 1 , the cell increases in size, the genomic DNA is assessed for damage, and the cell stockpiles energy reserves and the components to synthesize DNA. During the S phase, the chromosomes, the centrosomes, and the centrioles (animal cells) duplicate. During the G 2 phase, the cell recovers from the S phase, continues to grow, duplicates some organelles, and dismantles other organelles.
Chemotherapy drugs such as vincristine and colchicine disrupt mitosis by binding to tubulin (the subunit of microtubules) and interfering with microtubule assembly and disassembly. Exactly what mitotic structure is targeted by these drugs and what effect would that have on cell division?
- Answer
-
The mitotic spindle is formed of microtubules. Microtubules are polymers of the protein tubulin; therefore, it is the mitotic spindle that is disrupted by these drugs. Without a functional mitotic spindle, the chromosomes will not be sorted or separated during mitosis. The cell will arrest in mitosis and die.
Describe the similarities and differences between the cytokinesis mechanisms found in animal cells versus those in plant cells.
- Answer
-
There are very few similarities between animal cell and plant cell cytokinesis. In animal cells, a ring of actin fibers is formed around the periphery of the cell at the former metaphase plate (cleavage furrow). The actin ring contracts inward, pulling the plasma membrane toward the center of the cell until the cell is pinched in two. In plant cells, a new cell wall must be formed between the daughter cells. Due to the rigid cell walls of the parent cell, contraction of the middle of the cell is not possible. Instead, a phragmoplast first forms. Subsequently, a cell plate is formed in the center of the cell at the former metaphase plate. The cell plate is formed from Golgi vesicles that contain enzymes, proteins, and glucose. The vesicles fuse and the enzymes build a new cell wall from the proteins and glucose. The cell plate grows toward and eventually fuses with the cell wall of the parent cell.
List some reasons why a cell that has just completed cytokinesis might enter the G 0 phase instead of the G 1 phase.
- Answer
-
Many cells temporarily enter G 0 until they reach maturity. Some cells are only triggered to enter G 1 when the organism needs to increase that particular cell type. Some cells only reproduce following an injury to the tissue. Some cells never divide once they reach maturity.
What cell cycle events will be affected in a cell that produces mutated (non-functional) cohesin protein?
- Answer
-
If cohesin is not functional, chromosomes are not packaged after DNA replication in the S phase of interphase. It is likely that the proteins of the centromeric region, such as the kinetochore, would not form. Even if the mitotic spindle fibers could attach to the chromatids without packing, the chromosomes would not be sorted or separated during mitosis.
10.3: Control of the Cell Cycle
The length of the cell cycle is highly variable, even within the cells of a single organism. In humans, the frequency of cell turnover ranges from a few hours in early embryonic development, to an average of two to five days for epithelial cells, and to an entire human lifetime spent in G0 by specialized cells, such as cortical neurons or cardiac muscle cells. There is also variation in the time that a cell spends in each phase of the cell cycle.
Review Questions
At which of the cell cycle checkpoints do external forces have the greatest influence?
- G 1 checkpoint
- G 2 checkpoint
- M checkpoint
- G 0 checkpoint
- Answer
-
A
What is the main prerequisite for clearance at the G 2 checkpoint?
- cell has reached a sufficient size
- an adequate stockpile of nucleotides
- accurate and complete DNA replication
- proper attachment of mitotic spindle fibers to kinetochores
- Answer
-
C
If the M checkpoint is not cleared, what stage of mitosis will be blocked?
- prophase
- prometaphase
- metaphase
- anaphase
- Answer
-
D
Which protein is a positive regulator that phosphorylates other proteins when activated?
- p53
- retinoblastoma protein (Rb)
- cyclin
- cyclin-dependent kinase (Cdk)
- Answer
-
D
Many of the negative regulator proteins of the cell cycle were discovered in what type of cells?
- gametes
- cells in G 0
- cancer cells
- stem cells
- Answer
-
C
Which negative regulatory molecule can trigger cell suicide (apoptosis) if vital cell cycle events do not occur?
- p53
- p21
- retinoblastoma protein (Rb)
- cyclin-dependent kinase (Cdk)
- Answer
-
A
Free Response
Describe the general conditions that must be met at each of the three main cell cycle checkpoints.
- Answer
-
The G 1 checkpoint monitors adequate cell growth, the state of the genomic DNA, adequate stores of energy, and materials for S phase. At the G 2 checkpoint, DNA is checked to ensure that all chromosomes were duplicated and that there are no mistakes in newly synthesized DNA. Additionally, cell size and energy reserves are evaluated. The M checkpoint confirms the correct attachment of the mitotic spindle fibers to the kinetochores.
Explain the roles of the positive cell cycle regulators compared to the negative regulators.
- Answer
-
Positive cell regulators such as cyclin and Cdk perform tasks that advance the cell cycle to the next stage. Negative regulators such as Rb, p53, and p21 block the progression of the cell cycle until certain events have occurred.
What steps are necessary for Cdk to become fully active?
- Answer
-
Cdk must bind to a cyclin, and it must be phosphorylated in the correct position to become fully active.
Rb is a negative regulator that blocks the cell cycle at the G 1 checkpoint until the cell achieves a requisite size. What molecular mechanism does Rb employ to halt the cell cycle?
- Answer
-
Rb is active when it is dephosphorylated. In this state, Rb binds to E2F, which is a transcription factor required for the transcription and eventual translation of molecules required for the G 1 /S transition. E2F cannot transcribe certain genes when it is bound to Rb. As the cell increases in size, Rb becomes phosphorylated, inactivated, and releases E2F. E2F can then promote the transcription of the genes it controls, and the transition proteins will be produced.
10.4: Cancer and the Cell Cycle
Cancer is the result of unchecked cell division caused by a breakdown of the mechanisms that regulate the cell cycle. The loss of control begins with a change in the DNA sequence of a gene that codes for one of the regulatory molecules. Faulty instructions lead to a protein that does not function as it should. Any disruption of the monitoring system can allow other mistakes to be passed on to the daughter cells. Each successive cell division will give rise to daughter cells with even more damage
Review Questions
___________ are changes to the order of nucleotides in a segment of DNA that codes for a protein.
- Proto-oncogenes
- Tumor suppressor genes
- Gene mutations
- Negative regulators
- Answer
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C
A gene that codes for a positive cell cycle regulator is called a(n) _____.
- kinase inhibitor.
- tumor suppressor gene.
- proto-oncogene.
- oncogene.
- Answer
-
C
A mutated gene that codes for an altered version of Cdk that is active in the absence of cyclin is a(n) _____.
- kinase inhibitor.
- tumor suppressor gene.
- proto-oncogene.
- oncogene.
- Answer
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D
Which molecule is a Cdk inhibitor that is controlled by p53?
- cyclin
- anti-kinase
- Rb
- p21
- Answer
-
D
Free Response
Outline the steps that lead to a cell becoming cancerous.
- Answer
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If one of the genes that produces regulator proteins becomes mutated, it produces a malformed, possibly non-functional, cell cycle regulator, increasing the chance that more mutations will be left unrepaired in the cell. Each subsequent generation of cells sustains more damage. The cell cycle can speed up as a result of the loss of functional checkpoint proteins. The cells can lose the ability to self-destruct and eventually become “immortalized.”
Explain the difference between a proto-oncogene and a tumor suppressor gene.
- Answer
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A proto-oncogene is a segment of DNA that codes for one of the positive cell cycle regulators. If that gene becomes mutated so that it produces a hyperactivated protein product, it is considered an oncogene. A tumor suppressor gene is a segment of DNA that codes for one of the negative cell cycle regulators. If that gene becomes mutated so that the protein product becomes less active, the cell cycle will run unchecked. A single oncogene can initiate abnormal cell divisions; however, tumor suppressors lose their effectiveness only when both copies of the gene are damaged.
List the regulatory mechanisms that might be lost in a cell producing faulty p53.
- Answer
-
Regulatory mechanisms that might be lost include monitoring of the quality of the genomic DNA, recruiting of repair enzymes, and the triggering of apoptosis.
p53 can trigger apoptosis if certain cell cycle events fail. How does this regulatory outcome benefit a multicellular organism?
- Answer
-
If a cell has damaged DNA, the likelihood of producing faulty proteins is higher. The daughter cells of such a damaged parent cell would also produce faulty proteins that might eventually become cancerous. If p53 recognizes this damage and triggers the cell to self-destruct, the damaged DNA is degraded and recycled. No further harm comes to the organism. Another healthy cell is triggered to divide instead.
10.5: Prokaryotic Cell Division
In both prokaryotic and eukaryotic cell division, the genomic DNA is replicated and then each copy is allocated into a daughter cell. In addition, the cytoplasmic contents are divided evenly and distributed to the new cells. However, there are many differences between prokaryotic and eukaryotic cell division. Bacteria have a single, circular DNA chromosome but no nucleus. Therefore, mitosis is not necessary in bacterial cell division.
Review Questions
Which eukaryotic cell cycle event is missing in binary fission?
- cell growth
- DNA duplication
- karyokinesis
- cytokinesis
- Answer
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C
FtsZ proteins direct the formation of a _______ that will eventually form the new cell walls of the daughter cells.
- contractile ring
- cell plate
- cytoskeleton
- septum
- Answer
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B
Free Response
Name the common components of eukaryotic cell division and binary fission.
- Answer
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The common components of eukaryotic cell division and binary fission are DNA duplication, segregation of duplicated chromosomes, and division of the cytoplasmic contents.
Describe how the duplicated bacterial chromosomes are distributed into new daughter cells without the direction of the mitotic spindle.
- Answer
-
As the chromosome is being duplicated, each origin moves away from the starting point of replication. The chromosomes are attached to the cell membrane via proteins; the growth of the membrane as the cell elongates aids in their movement.


16.4: Overview
| Official course description: | This course is designed to explore the biological aging process as part of the normal developmental sequence and process of change from conception to death. This aging process will be viewed as the developmental continuum that occurs in all human beings. Typical biological aging changes in all body systems, as well as some disease processes, will be discussed. |
| Credits: | 3 |
| Course prerequisites: | None |
This course is fully online. This course is divided into seven scheduled modules, a course information area, an ice breaking module, and a course survey section. Each scheduled module may include readings, discussion, quizzes, and written assignments.
Module 1: Introduction to Human Again, Theories of Aging, and Cellular Aging
Module 2: The Integumentary System, Skeletal System, and Muscular System
Module 3: The Nervous System & Special Senses
Module 4: The Circulatory, Immune, and Respiratory System
Module 5: The Digestive and Urinary System
Module 6: The Reproductive and Endocrine System
Module 7: Term Research Project
Contributors and Attributions
- Overview. Authored by : Kelly, Jessica. Provided by : Herkimer College. Project : ATD Course. License : CC BY: Attribution


6.8: Piezoelectricity
Piezoelectricity is the property presented by certain materials that exhibit an electric polarization when submitted to an applied mechanical stress such as a uniaxial compression. Conversely, their shape changes when they are submitted to an external electric field; this is the converse piezoelectric effect. The piezoelectric effect and the converse effect are described by third-rank tensors:
- For a small stress, represented by a second-rank tensor, T ij , the resulting polarization, of components P k , is given by:
P k = d kij T ij
where d kij is a third-rank tensor representing the direct piezoelectric effect.
- For a small applied electric field, of components E k , the resulting strain, represented by a second-rank tensor, S ij , is given by:
S ij = d ijk E k + Q ijkl E k E l
where the first-order term, d ijk , represents the inverse piezoelectric effect and the second-order term, Q ijkl , a symmetric fourth-rank tensor, the electrostriction effect. The sense of the strain due to the piezoelectric effect changes when the sign of the applied electric field changes , while that due to electrostriction, a quadratic effect, does not.
The matrices associated to the coefficients d kij and d kij of the direct and converse piezoelectric effects, respectively, are transpose of one another.


26.4: Summary
26.1 Structure and Function
The structures of the neurological system include the CNS and PNS. The CNS includes the brain and spinal cord and is responsible for receiving, processing, and responding to sensory information. The brain is the organ responsible for sensation , movement, emotions, responses, thought processing, communication, and memory. The spinal cord sends motor commands from the brain to the peripheral body and also relays sensory information from sensory organs to the brain. The PNS includes the cranial nerves, spinal nerves, and autonomic nervous system . The primary function of the PNS is to connect the CNS to the limbs and organs. Peripheral nerves are categorized as either sensory or motor nerves, or a combination of the two. Sensory nerves transmit impulses from the body to the brain for processing. Motor nerves conduct motor signals from the brain to the muscles to initiate movement. Physical effects of an impaired nervous system include dizziness, loss of balance or gait issues, dysphagia , muscle weakness, paralysis, loss of senses, headaches, and inability to perform ADLs. Psychological effects of an impaired neurological system include, but are not limited to, depression, changes in cognition, fear of losing control, and anxiety.
26.2 Physical Assessment
The comprehensive neurological assessment requires the nurse to collect both subjective and objective data through an interview as well as a detailed physical exam . The nurse will collect a complete health history, using effective communication to identify any issues or potential concerns, because some issues may only identified through precise questioning during the interview. The nurse will also collect objective data to assess the patient’s mental status, appearance, motor and sensory functions, cranial nerve function, and deep tendon reflexes. Tests that may be used include, but are not limited to, the GCS, NIH Stroke Scale, MMSE, various cranial nerve assessments, heel-to-shin test, and finger-to-nose test. The nurse should be able to identify expected versus abnormal findings. For example, as part of assessing the patient’s orientation, the nurse should recognize a potential alteration if the patient provides an incorrect date. The nurse should also validate and document their findings. The documentation should be comprehensive to provide baseline information for future comparisons.
26.3 Recognizing Common Neurological Disorders
Cognitive disorders are those that affect the cognitive function of an individual, such as how the brain processes and stores information. Cognitive disorders affect behavior, memory, communication, learning, perception, problem-solving, and the ability to reason; and include headaches and facial pain; degenerative disorders such as dementia , Alzheimer, Parkinson, and Huntington diseases, and MS; seizure disorders such as epilepsy ; cerebrovascular accidents; and neurological infections. Spinal cord injuries include any injury to the vertebral column, supporting soft tissue, intervertebral discs, or the spinal cord itself. These injuries may be due to lacerations, concussion, tissue compression, or complete severing of the spinal cord. Types of spinal cord injuries include Brown-Séquard syndrome, central cord syndrome, anterior cord syndrome, and posterior cord syndrome. Developmental disorders vary but include conditions that result in impairment in learning, language, behavior, and movement. These conditions may develop at or during conception or shortly after birth. Types of developmental disorders include cerebral palsy, intellectual disability, and prenatal injuries.


1.2: Electromagnetic Spectrum
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Electromagnetic fields exist at frequencies from DC (0 Hz) to at least 10 20 Hz – that’s at least 20 orders of magnitude! At DC, electromagnetics consists of two distinct disciplines: electrostatics , concerned with electric fields; and magnetostatics , concerned with magnetic fields. At higher frequencies, electric and magnetic fields interact to form propagating waves. Waves having frequencies within certain ranges are given names based on how they manifest as physical phenomena. These names are (in order of increasing frequency): radio, infrared (IR), optical (also known as “light”), ultraviolet (UV), X-rays, and gamma rays (γ-rays). See Table \(\PageIndex{1}\) and Figure \(\PageIndex{1}\) for frequency ranges and associated wavelengths.
Definition: Electromagnetic Spectrum
The term electromagnetic spectrum refers to the various forms of electromagnetic phenomena that exist over the continuum of frequencies
The speed (properly known as “phase velocity”) at which electromagnetic fields propagate in free space is given the symbol \(c\), and has the value \(\cong 3.00 \times 10^{8}\) m/s. This value is often referred to as the “speed of light.” While it is certainly the speed of light in free space, it is also the speed of any electromagnetic wave in free space. Given frequency \(f\), wavelength is given by the expression
\[ \underbrace{\lambda = \frac { c } { f }}_{\text{in free space}} \nonumber \]
Table \(\PageIndex{1}\) shows the free space wavelengths associated with each of the regions of the electromagnetic spectrum. This book presents a version of electromagnetic theory that is based on classical physics. This approach works well for most practical problems. However, at very high frequencies, wavelengths become small enough that quantum mechanical effects may be important. This is usually the case in the X-ray band and above. In some applications, these effects become important at frequencies as low as the optical, IR, or radio bands. (A prime example is the photoelectric effect ; see “Additional References” below.) Thus, caution is required when applying the classical version of electromagnetic theory presented here, especially at these higher frequencies.
| Regime | Frequency Range | Wavelength Range |
|---|---|---|
| \(\gamma\)-Ray | \(\mathrm{> 3 \times 10^{19} \; Hz}\) | < 0.01 nm |
| X-Ray | \(\mathrm{3 \times 10^{16} \; Hz \; – \; 3 \times 10^{19} \; Hz}\) | 10–0.01 nm |
| Ultraviolet (UV) | \(\mathrm{2.5 \times 10^{15} \; – \; 3 \times 10^{16} \; Hz}\) | 120–10 nm |
| Optical | \(\mathrm{4.3 \times 10^{14} \; – \; 2.5 \times 10^{15} \; Hz}\) | 700–120 nm |
| Infrared (IR) | \(\mathrm{300 \; GHz \; – \; 4.3 \times 10^{14} \; Hz}\) | 1 mm – 700 nm |
| Radio | \(\mathrm{3 \; kHz – 300 \; GHz}\) | 100 km – 1 mm |
The radio portion of the electromagnetic spectrum alone spans 12 orders of magnitude in frequency (and wavelength), and so, not surprisingly, exhibits a broad range of phenomena. This is shown in Figure \(\PageIndex{1}\).
Figure \(\PageIndex{1}\): Electromagnetic Spectrum.| Band | Frequencies | Wavelengths | Typical Applications |
|---|---|---|---|
| EHF | 30-300 GHz | 10–1 mm | 60 GHz WLAN, Point-to-point data links |
| SHF | 3–30 GHz | 10–1 cm | Terrestrial & Satellite data links, Radar |
| UHF | 300–3000 MHz | 1–0.1 m | TV broadcasting, Cellular, WLAN |
| VHF | 30–300 MHz | 10–1 m | FM & TV broadcasting, LMR |
| HF | 3–30 MHz | 100–10 m | Global terrestrial comm., CB Radio |
| MF | 300–3000 kHz | 1000–100 m | AM broadcasting |
| LF | 30–300 kHz | 10–1 km | Navigation, RFID |
| VLF | 3–30 kHz | 100–10 km | Navigation |
| Band | Frequencies | Wavelengths |
|---|---|---|
| Violet | 668–789 THz | 450–380 nm |
| Blue | 606–668 THz | 495–450 nm |
| Green | 526–606 THz | 570–495 nm |
| Yellow | 508–526 THz | 590–570 nm |
| Orange | 484–508 THz | 620–590 nm |
| Red | 400–484 THz | 750–620 nm |


1.113: Wigner-Seitz cell
The Wigner-Seitz cell is a a polyhedron obtained by connecting a lattice point P to all other lattice points and drawing the planes perpendicular to these connecting lines and passing through their midpoints (Figure 1). The polyhedron enclosed by these planes is the Wigner-Seitz cell. This construction is called the Dirichlet construction. The cell thus obtained is a primitive cell and it is possible to fill up the whole space by translation of that cell.
The Wigner-Seitz cell of a body-centered cubic lattice I is a cuboctahedron (Figure 2) and the Wigner-Seitz cell of a face-centered cubic lattice F is a rhomb-dodecahedron (Figure 3). In reciprocal space this cell is the first Brillouin zone. Since the reciprocal lattice of body-centered lattice is a face-centered lattice and reciprocally, the first Brillouin zone of a body-centered cubic lattice is a rhomb-dodecahedron and that of a face-centered cubic lattice is a cuboctahedron.
The inside of the Wigner-Seitz cell has been called domain of influence by Delaunay (1933). It is also called Dirichlet domain or Voronoi domain. The domain of influence of lattice point P thus consists of all points Q in space that are closer to this lattice point than to any other lattice point or at most equidistant to it (such that OP ≤ | t - OP | for any vector t ∈ L ).


3.4: Questioning Strategies
Questioning Circles
The questioning circles are a graphical representation (a form of a Venn diagram) of three domains: You, the Text, and the World (or another text). When you create questions based on a domain, or a combination of domains, it can help you examine and think about an idea more deeply. This, in turn, can help you understand and think about your reading and help you develop your writing.
There are three levels of questions in this model:
Level 1 (Clear) Questions: These are about one domain only and can only be answered with a fact.
Level 2 (Shaded) Questions: These are questions about a combination of two domains and require interpretation and an opinion by the person who answers the question.
Level 3 (Dense) Questions: These questions combine all three domains. They require interpretation, and usually there is no one right answer. Level 3 questions make great essay questions!
The following figure is a graphic representation of the domains you would ask about when creating questions: you, the text, and another world or another text. Please note that a text can be anything you "read," from a class reading assignment, to a movie, etc.
Figure 3.3.1: Questioning Circle Domains
Examples of Questioning Circle Questions
Level 1 questions can be answered with facts only.
- Level 1 question about you : Have you ever experienced xx?
- Level 1 question about the text : What was the setting in the text in Chapter x?
- Level 1 question about the world : How often does x occur in the world?
Level 2 questions combine two of the domains. They can only be answered with an opinion (an educated opinion).
- Level 2 question about you and the text: Do you think you would respond in the same way as (character) did if you were in that situation?
- Level 2 question about you and the world : What have your experiences in the world in relation to xxx been like?
- Level 2 question about the text and the world: Are (character’s) experiences in the book representative of how most people in the world experience this situation?
- Level 2 question about the text and another text : How do the characters in [novel] and [novel] react differently to similar situations?
Level 3 questions ask questions about a combination of all three domains. These questions cannot be answered definitively and generally require readers to compare ideas about issues that can't easily be answered.
Level 3 question about you, text, and the world : How do you think a person’s past experiences inform how they interact with people in situations such as those in which [characters] found themselves?
Contributors
CC LICENSED CONTENT, ORIGINAL:
- Revision, Adaptation, and Original Content. Provided by: Libretexts. License: CC BY-SA 4.0: Attribution.
This page was most recently updated on June 6, 2020.


7.3B: DNA Replication in Eukaryotes
- Describe how DNA is replicated in eukaryotes
Because eukaryotic genomes are quite complex, DNA replication is a very complicated process that involves several enzymes and other proteins. It occurs in three main stages: initiation, elongation, and termination. DNA replication in eukaryotes occurs in three stages: initiation, elongation, and termination, which are aided by several enzymes.
Initiation
Eukaryotic DNA is bound to proteins known as histones to form structures called nucleosomes. During initiation, the DNA is made accessible to the proteins and enzymes involved in the replication process. There are specific chromosomal locations called origins of replication where replication begins. In some eukaryotes, like yeast, these locations are defined by having a specific sequence of basepairs to which the replication initiation proteins bind. In other eukaryotes, like humans, there does not appear to be a consensus sequence for their origins of replication. Instead, the replication initiation proteins might identify and bind to specific modifications to the nucleosomes in the origin region.
Certain proteins recognize and bind to the origin of replication and then allow the other proteins necessary for DNA replication to bind the same region. The first proteins to bind the DNA are said to “recruit” the other proteins. Two copies of an enzyme called helicase are among the proteins recruited to the origin. Each helicase unwinds and separates the DNA helix into single-stranded DNA. As the DNA opens up, Y-shaped structures called replication forks are formed. Because two helicases bind, two replication forks are formed at the origin of replication; these are extended in both directions as replication proceeds creating a replication bubble. There are multiple origins of replication on the eukaryotic chromosome which allow replication to occur simultaneously in hundreds to thousands of locations along each chromosome.
Elongation
During elongation, an enzyme called DNA polymerase adds DNA nucleotides to the 3′ end of the newly synthesized polynucleotide strand. The template strand specifies which of the four DNA nucleotides (A, T, C, or G) is added at each position along the new chain. Only the nucleotide complementary to the template nucleotide at that position is added to the new strand.
DNA polymerase contains a groove that allows it to bind to a single-stranded template DNA and travel one nucleotide at at time. For example, when DNA polymerase meets an adenosine nucleotide on the template strand, it adds a thymidine to the 3′ end of the newly synthesized strand, and then moves to the next nucleotide on the template strand. This process will continue until the DNA polymerase reaches the end of the template strand.
DNA polymerase cannot initiate new strand synthesis; it only adds new nucleotides at the 3′ end of an existing strand. All newly synthesized polynucleotide strands must be initiated by a specialized RNA polymerase called primase. Primase initiates polynucleotide synthesis and by creating a short RNA polynucleotide strand complementary to template DNA strand. This short stretch of RNA nucleotides is called the primer. Once RNA primer has been synthesized at the template DNA, primase exits, and DNA polymerase extends the new strand with nucleotides complementary to the template DNA.
Eventually, the RNA nucleotides in the primer are removed and replaced with DNA nucleotides. Once DNA replication is finished, the daughter molecules are made entirely of continuous DNA nucleotides, with no RNA portions.
The Leading and Lagging Strands
DNA polymerase can only synthesize new strands in the 5′ to 3′ direction. Therefore, the two newly-synthesized strands grow in opposite directions because the template strands at each replication fork are antiparallel. The “leading strand” is synthesized continuously toward the replication fork as helicase unwinds the template double-stranded DNA.
The “lagging strand” is synthesized in the direction away from the replication fork and away from the DNA helicase unwinds. This lagging strand is synthesized in pieces because the DNA polymerase can only synthesize in the 5′ to 3′ direction, and so it constantly encounters the previously-synthesized new strand. The pieces are called Okazaki fragments, and each fragment begins with its own RNA primer.
Termination
Eukaryotic chromosomes have multiple origins of replication, which initiate replication almost simultaneously. Each origin of replication forms a bubble of duplicated DNA on either side of the origin of replication. Eventually, the leading strand of one replication bubble reaches the lagging strand of another bubble, and the lagging strand will reach the 5′ end of the previous Okazaki fragment in the same bubble.
DNA polymerase halts when it reaches a section of DNA template that has already been replicated. However, DNA polymerase cannot catalyze the formation of a phosphodiester bond between the two segments of the new DNA strand, and it drops off. These unattached sections of the sugar-phosphate backbone in an otherwise full-replicated DNA strand are called nicks.
Once all the template nucleotides have been replicated, the replication process is not yet over. RNA primers need to be replaced with DNA, and nicks in the sugar-phosphate backbone need to be connected.
The group of cellular enzymes that remove RNA primers include the proteins FEN1 (flap endonulcease 1) and RNase H. The enzymes FEN1 and RNase H remove RNA primers at the start of each leading strand and at the start of each Okazaki fragment, leaving gaps of unreplicated template DNA. Once the primers are removed, a free-floating DNA polymerase lands at the 3′ end of the preceding DNA fragment and extends the DNA over the gap. However, this creates new nicks (unconnected sugar-phosphate backbone).
In the final stage of DNA replication, the enyzme ligase joins the sugar-phosphate backbones at each nick site. After ligase has connected all nicks, the new strand is one long continuous DNA strand, and the daughter DNA molecule is complete.
DNA Replication : This is a clip from a PBS production called “DNA: The Secret of Life.” It details the latest research (as of 2005) concerning the process of DNA replication.
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LICENSES AND ATTRIBUTIONS
Key Points
- During initiation, proteins bind to the origin of replication while helicase unwinds the DNA helix and two replication forks are formed at the origin of replication.
- During elongation, a primer sequence is added with complementary RNA nucleotides, which are then replaced by DNA nucleotides.
- During elongation the leading strand is made continuously, while the lagging strand is made in pieces called Okazaki fragments.
- During termination, primers are removed and replaced with new DNA nucleotides and the backbone is sealed by DNA ligase.
Key Terms
- origin of replication : a particular sequence in a genome at which replication is initiated
- leading strand : the template strand of the DNA double helix that is oriented so that the replication fork moves along it in the 3′ to 5′ direction
- lagging strand : the strand of the template DNA double helix that is oriented so that the replication fork moves along it in a 5′ to 3′ manner


9.2: Unit B- Ways to Make the Most Effective Use of the Family’s Finances
In addition to helping the family plan and work within a budget , Home Health Aides/Personal Care Aides can also help the family cut or reduce their costs. Costs can be reduced in many ways. We often do not even realize all the little things we can do to cut our costs.  Here are some ways Home Health Aides/Personal Care Aides can help their patient and their family cut costs and things they can think about doing to help the family save money!
The following tips will help the Home Health Aide/Personal Care Aide assist the families with whom they work to save on groceries, household costs, and energy costs. You can view these and other tips to save on groceries and household expenses by visiting American Consumer Credit Counseling at: http :// www . consumercredit . com / media /90298/ Save – by – Cutting – Back -2013. pdf


1.1: Introduction
Evolution is happening all around us. In many cases – lately, due to technological advances in molecular biology – scientists can now describe the evolutionary process in exquisite detail. For example, we know exactly which genes change in frequency from one generation to the next as mice and lizards evolve a white color to match the pale sands of their novel habitats (Rosenblum et al. 2010) . We understand the genetics, development, and biomechanical processes that link changes in a Galapagos finches’ diet to the shape of their bill (Abzhanov et al. 2004) . And, in some cases, we can watch as one species splits to become two (for example, Rolshausen et al. 2009) .
Detailed studies of evolution over short time-scales have been incredibly fruitful and important for our understanding of biology. But evolutionary biologists have always wanted more than this. Evolution strikes a chord in society because it aims to tell us how we, along with all the other living things that we know about, came to be. This story stretches back some 4 billion years in time. It includes all of the drama that one could possibly want – sex, death, great blooms of life and global catastrophes. It has had “winners” and “losers,” groups that wildly diversified, others that expanded then crashed to extinction, as well as species that have hung on in basically the same form for hundreds of millions of years.
There is, perhaps, no more evocative symbol of this grand view of evolution over deep time than the tree of life (Figure 1.1; Rosindell and Harmon 2012) . This branching phylogenetic tree connects all living things through a series of splitting events to a single common ancestor. Recent research has dramatically increased our knowledge of the shape and form of this tree. The tree of life is a rich treasure-trove of information, telling us how species are related to one another, which groups are exceptionally diverse or depauperate, and how life has evolved, formed new species, and spread over the globe. Our knowledge of the tree of life, still incomplete but advancing every day, promises to transform our understanding of evolution at the grandest scale (Baum and Smith 2012) .
Knowing the evolutionary processes that operate over the course of a few generations, even in great detail, does not automatically give insight into why the tree of life is shaped the way that it is. At the same time, it seems reasonable to hypothesize that the same processes that we can observe now - natural selection, genetic drift, migration, sexual selection, and so on - have been occurring for the last four billion years or so along the branches of the tree. A major challenge for evolutionary biology, then, comes in connecting our knowledge of the mechanisms of evolution with broad-scale patterns seen in the tree of life. This “tree thinking” is what we will explore here.
In this book, I describe methods to connect evolutionary processes to broad-scale patterns in the tree of life. I focus mainly – but not exclusively – on phylogenetic comparative methods. Comparative methods combine biology, mathematics, and computer science to learn about a wide variety of topics in evolution using phylogenetic trees and other associated data (see Harvey and Pagel 1991 for an early review) . For example, we can find out which processes must have been common, and which rare, across clades in the tree of life; whether evolution has proceeded differently in some lineages compared to others; and whether the evolutionary potential that we see playing out in real time is sufficient to explain the diversity of life on earth, or whether we might need additional processes that may come into play only very rarely or over very long timescales, like adaptive radiation or species selection.
This introductory chapter has three sections. First, I lay out the background and context for this book, highlighting the role that I hope it will play for readers. Second, I include some background material on phylogenies - both what they are, and how they are constructed. This is necessary information that leads into the methods presented in the remainder of the chapters of the book; interested readers can also read Felsenstein (Felsenstein 2004) , which includes much more detail. Finally, I briefly outline the book’s remaining chapters.


3.1: Prelude to India
The Bhagavad-Gita is the most directly religious work, containing as it does the teaching of the god Vishnu through his avatar Krishna, but the other two texts include direct participation of gods (and their avatars) in the stories. Therefore, some basic information about Hinduism is necessary for a clear understanding of the texts:
The one god is Brahman, who both binds the universe together and transcends it. The consciousness of Brahman is divided into three parts, which worshippers address individually:
- Brahma, the Creator
- Vishnu, the Preserver
- Shiva, the Destroyer
Each of them is represented by hundreds of minor Hindu gods, who represent aspects of these three and can function separately while still remaining part of the whole (and all of them are part of Brahman). Gods also can send down avatars—pieces of their consciousness that are born, live, and die as humans—to intervene when necessary
In all three works, a belief in samsara—the cycle of reincarnation—drives the characters’ behavior. An individual can move up or down the hierarchy in society based on their karma (the sum of their good and bad deeds), but only in their next reincarnation. For each person, the concept of dharma (doing what one is supposed to do, right behavior, Law) is slightly different: A warrior who takes an oath (no matter how crazy an oath it is) must fulfill his oath, because keeping one’s word is part of a warrior’s honor. Not fulfilling an oath is adharma (described as Unlaw in the texts). A farmer, however, should behave like a good farmer, rather than a warrior, and good farmers do not take crazy oaths or act in ways that could damage their ability to plant and harvest a crop. Farmers also should not try to become warriors. Social mobility, therefore, is not only discouraged, but irreligious in that context. This idea drives the caste system, forcing people to remain in their caste or face being made an Untouchable.
Each character is born into a caste, or Varna, which determines what they can and cannot do, and each Varna is broken down into numerous Jats, or communities:
- Brahmins, the priests and scholars, are the highest Varna.
- Kshatriyas, the rulers and the military, are the next level.
- Vaishyas are the farmers, landlords, and merchants.
- Sudras are peasants, servants, and works in non-polluting jobs.
The Dalit, or Untouchables, are workers in what are considered polluting jobs. In some places, even contact with the shadow of an Untouchable was considered polluting. In some parts of India (mostly rural districts), the caste system continues, despite government attempts to stop it.
Characters need to be the best they can be (following their individual dharma) in the Varna and Jat into which they were born in order to move up the hierarchy in their next reincarnation. They are expected not only to work in their Jat, but to marry within it. Certain problems in The Mahabharata are a direct result of characters who do not stay in their Jat (or even their Varna), and the story warns us that trouble, and even disaster, will follow.


12.2A: Classification of Receptors by Stimulus
Sensory receptors are primarily classified as chemoreceptors, thermoreceptors, mechanoreceptors, or photoreceptors.
- Differentiate among the types of stimuli to which receptors respond
Key Points
- Chemoreceptors detect the presence of chemicals.
- Thermoreceptors detect changes in temperature.
- Mechanoreceptors detect mechanical forces.
- Photoreceptors detect light during vision.
- More specific examples of sensory receptors are baroreceptors, propioceptors, hygroreceptors, and osmoreceptors.
- Sensory receptors perform countless functions in our bodies mediating vision, hearing, taste, touch, and more.
Key Terms
- photoreceptor : A specialized neuron able to detect and react to light.
- mechanoreceptor : Any receptor that provides an organism with information about mechanical changes in its environment such as movement, tension, and pressure.
- baroreceptor : A nerve ending that is sensitive to changes in blood pressure.
Sensory receptors can be classified by the type of stimulus that generates a response in the receptor. Broadly, sensory receptors respond to one of four primary stimuli:
- Chemicals (chemoreceptors)
- Temperature (thermoreceptors)
- Pressure (mechanoreceptors)
- Light (photoreceptors)
A schematic of the classes of sensory receptors : Sensory receptor cells differ in terms of morphology, location, and stimulus.
All sensory receptors rely on one of these four capacities to detect changes in the environment, but may be tuned to detect specific characteristics of each to perform a specific sensory function. In some cases, the mechanism of action for a receptor is not clear. For example, hygroreceptors that respond to changes in humidity and osmoreceptors that respond to the osmolarity of fluids may do so via a mechanosensory mechanism or may detect a chemical characteristic of the environment.
Sensory receptors perform countless functions in our bodies. During vision, rod and cone photoreceptors respond to light intensity and color. During hearing, mechanoreceptors in hair cells of the inner ear detect vibrations conducted from the eardrum. During taste, sensory neurons in our taste buds detect chemical qualities of our foods including sweetness, bitterness, sourness, saltiness, and umami (savory taste). During smell, olfactory receptors recognize molecular features of wafting odors. During touch, mechanoreceptors in the skin and other tissues respond to variations in pressure.
Classification of Sensory Receptors
Adequate Stimulus
Adequate stimulus can be used to classify sensory receptors. A sensory receptor’s adequate stimulus is the stimulus modality for which it possesses the adequate sensory transduction apparatus.
| Sensory receptors with corresponding stimuli to which they respond. | |
|---|---|
| Receptor | Stimulus |
| Apmullae of Lorenzini (primarily function as electroreceptors) | Electric fields, salinity, and temperature |
| Baroreceptors | Pressure in blood vessels |
| Chemo receptors | Chemical stimuli |
| Electromagnetic radiation receptors | Electromagnetic radiation |
| Electroreceptors | Electrofields |
| Hydroreceptors | Humidity |
| Infrared receptors | Infrared radiation |
| Magnetoreceptors | Magnetic fields |
| Mechanoreceptors | Mechanical stress or strain |
| Nociceptors | Damage or threat of damage to body tissues (leads to pain perception) |
| Osmoreceptors | Osmolarity of fluids |
| Photoreceptors | Visible light |
| Proprioceptors | Sense of position |
| Thermoreceptors | Temperature |
| Ultraviolet receptors | Ultraviolet radiation |
Location
Sensory receptors can be classified by location:
- Cutaneous receptors are sensory receptors found in the dermis or epidermis.
- Muscle spindles contain mechanoreceptors that detect stretch in muscles.
Morphology
Somatic sensory receptors near the surface of the skin can usually be divided into two groups based on morphology:
- Free nerve endings characterize the nociceptors and thermoreceptors.
- Encapsulated receptors consist of the remaining types of cutaneous receptors. Encapsulation exists for specialized functioning.
Rate of Adaptation
A tonic receptor is a sensory receptor that adapts slowly to a stimulus, while a phasic receptor is a sensory receptor that adapts rapidly to a stimulus.


13: Ethics in Business Last updated Save as PDF Page ID 47573 Lumen Learning Lumen Learning 13.1: Introduction to Corporate Social Responsibility 13.2: Corporate Social Responsibility 13.3: Putting It Together- Ethics in Business 13.4: Assignment- Culture Survey at Sun City Boards 13.5: Assignment- Memo to 3M CEO 13.6: Discussion- Sun City Boards’ Code of Ethics 13.7: Discussion- Are They Simply Guidelines? 13.8: Why It Matters- Ethics in Business 13.9: Introduction to the Need for Ethics in the Workplace 13.10: The Need for Ethics in the Workplace 13.11: Introduction to US Sentencing Guidelines for Organizations 13.12: US Sentencing Guidelines for Organizations 13.13: Introduction to Influences on Ethical Choices 13.14: Influences on Ethical Choices 13.15: Introduction to How Managers Can Encourage Ethical Behavior 13.16: How Managers Can Encourage Ethical Behavior


4.6: Homework- Optimization
-
Samantha has some whiskey at a party, and (being a science and math geek) estimates her blood alcohol content (BAC) follows the function:
\(BAC(t) = \frac{0.25 t}{e^t},\)
where \(t\) is measured in hours after her first drink. Graph this function, and determine the following using a derivative:
-
How quickly is her BAC increasing (or decreasing) 15 minutes after her first drink?
\(BAC'(t) = \frac{0.25 - 0.25t}{e^t}\), (grams per dL per hour).ans
-
How quickly is her BAC increasing (or decreasing) 1 hour after her first drink?
\(0\) changeans
-
How quickly is her BAC increasing (or decreasing) 2 hours after her first drink?
\(\approx 0.034\) grams per dL per hourans
-
How quickly is her BAC increasing (or decreasing) 15 minutes after her first drink?
-
Graph each function over the given interval. Use calculus to determine the location of all global and local mins and maxes.
-
\(f(x) = -x^2 + 5x - 2\) on the interval \([0, 5]\).
Local and Global Mins: \((0, -2), (5, -2)\), Local and global max: \((2.5, 4.25)\)ans
-
\(f(x) = x^2 - 6x + 10\) on the interval \([2, 6]\).
Local min: \((2, 2)\), global and local min: \((3, 1)\), local and global max: \((6, 10)\)ans
-
\(f(x) = x^3 - 6x^2 + 11x - 6\) on the interval \([0, 3]\).
Local and global maximum at \((1.42, 0.38 )\), Local min: \((2.58,-0.38 )\), local and global minimum: \((0, -6)\), local maximum: \((3, -2)\)ans
-
\(f(x) = x^3-5 x^2+8 x-4\) on the interval \([0, 2.5]\).
Local max at \(x = 0.75\), local min at \(x = 2\), global max at \(x = 2.5\), global min at \(x = 0\).ans
-
\(f(x) = x^4 - 16x\) on the interval \([0, 3]\).
Local max at \(x = 0\), global min at \(x = \sqrt[3]{4}\), global max at \(x = 3\)ans
-
\(f(x) = \frac{x^2}{x + 1}\) on the interval \([-3, 3]\).
Local min at \(x = -3\), local max at \(x = -2\), local min at \(x = 0\), local max at \(x = 3\)ans
-
\(f(x) = -x^2 + 5x - 2\) on the interval \([0, 5]\).
-
Using a chemotherapy drug on a petri-dish of cancer cells, it is found that \(P(x)\) percent more of the cancer cells are killed using \(x\) milligrams of drug per square centimeter than healthy cells, where \(x\) ranges from \(0\) to \(4\). It is thought
\(P(x) = x^3-8 x^2+16 x\)
For what value of \(x\) is \(P(x)\) maximized?
ans -
Bananas as we know them may be doomed!
Suppose the fungus Tropical Race 4 mentioned in the article is killing off bananas on an island in Jamaica. The number of viable banana farms starts at \(16000\), with \(800\) being forced to close per year. But new banana farms are according to the function \(20e^{0.3t}\) with new varieties immune to the fungus (\(t\) measured in years). So the total number of viable banana farms is
\(V(t) = 16000- 800t + 20e^{0.3t}\)
on the interval \([0, 20]\). At what point is the number of banana farms minimized? What is the number of viable banana farms at this point?
This function is minimized at \(t \approx 16.3\) with the number of banana farms at \(5619\)ans - The area of a rectangle is length times width.  What is the maximum amount of area he can enclose?
-
Watch the KhanAcademy videos on maximizing the area of a box:
Optimizing Box Volume Graphically and
Optimizing Box Volume Analytically -
An open-topped box is formed by removing the square corners of sidelength \(x\) off of a \(40\) in by \(80\) in piece of cardboard, and folding each side up. What value of \(x\) maximizes the volume of the box?
\(x \approx 8.45\)ans
-
The height and radius of a cone together add to \(5\) inches. What value of the radius maximizes the volume? The volume is given by \(V = \frac{1}{3} \pi r^2 h\).
inans


25: Carbohydrates
This chapter is designed to provide you with an overview of the biologically important group of compounds known as carbohydrates. Many of the compounds you will encounter while studying this chapter may appear to have very complex structures, but much of their chemistry can be readily understood in terms of the concepts and reactions discussed in earlier chapters of the course.
The chapter begins with an explanation of the classification schemes used to simplify the study of carbohydrates. We make extensive use of Fischer projection formulas throughout the chapter. We place considerable emphasis on gaining an appreciation of the configurations of carbohydrates, particularly of the aldoses. We describe the disadvantages of representing monosaccharides by open-chain structures, and at this point, introduce you to cyclic representations—called Haworth projections—of these substances. We describe the mutarotation of glucose, explaining it in terms of the existence of anomers. We then examine some reactions of monosaccharides, including the formation of ethers and esters, the formation of glycosides, and reduction and oxidation. We discuss the structures of some common disaccharides and polysaccharides, and conclude the chapter with a brief explanation of the role played by carbohydrates in cell recognition.
-
- 25.2: Depicting Carbohydrate Stereochemistry - Fischer Projections
- The wedge and dash notations we have been using are effective for drawing three-dimensional configurations on a two-dimensional surface,, but can be troublesome when applied to compounds having many chiral centers. Emil Fischer devised a simple notation that is still widely used. Fischer Projections allow us to represent 3D molecular structures in a 2D environment without changing their properties and/or structural integrity.
-
- 25.6: Reactions of Monosaccharides
- Monosaccharides contain both alcohol and carbonyl functional groups. This allows monosaccharides to undergo many of the reactions typical for these functional groups. In particular, alcohols can be converted to esters, converted to ethers, converted to acetals, or oxidized. Carbonyls can be reacted with nucleophiles, be reduced to form alcohols, or be oxidized to form carboxylic acids.


3.1.8: Variants of Turing Machines
There are in fact many possible ways to define Turing machines, of which ours is only one. In some ways, our definition is more liberal than others. We allow arbitrary finite alphabets, a more restricted definition might allow only two tape symbols, \(\TMstroke\) and \(\TMblank\) . We allow the machine to write a symbol to the tape and move at the same time, other definitions allow either writing or moving. We allow the possibility of writing without moving the tape head, other definitions leave out the \(\TMstay\) “instruction.” In other ways, our definition is more restrictive. We assumed that the tape is infinite in one direction only, other definitions allow the tape to be infinite both to the left and the right. In fact, one can even allow any number of separate tapes, or even an infinite grid of squares. We represent the instruction set of the Turing machine by a transition function; other definitions use a transition relation where the machine has more than one possible instruction in any given situation.
This last relaxation of the definition is particularly interesting. In our definition, when the machine is in state \(q\) reading symbol \(\sigma\) , \(\delta(q, \sigma)\) determines what the new symbol, state, and tape head position is. But if we allow the instruction set to be a relation between current state-symbol pairs \(\tuple{q, \sigma}\) and new state-symbol-direction triples \(\tuple{q', \sigma', D}\) , the action of the Turing machine may not be uniquely determined—the instruction relation may contain both \(\tuple{q, \sigma, q', \sigma', D}\) and \(\tuple{q, \sigma, q'', \sigma'', D'}\) . In this case we have a non-deterministic Turing machine. These play an important role in computational complexity theory.
There are also different conventions for when a Turing machine halts: we say it halts when the transition function is undefined, other definitions require the machine to be in a special designated halting state. Since the tapes of our Turing machines are infinite in one direction only, there are cases where a Turing machine can’t properly carry out an instruction: if it reads the leftmost square and is supposed to move left. According to our definition, it just stays put instead, but we could have defined it so that it halts when that happens.
There are also different ways of representing numbers (and hence the input-output function computed by a Turing machine): we use unary representation, but you can also use binary representation. This requires two symbols in addition to \(\TMblank\) and \(\TMendtape\) .
Now here is an interesting fact: none of these variations matters as to which functions are Turing computable. If a function is Turing computable according to one definition, it is Turing computable according to all of them.


2.3: Cædmon’s Hymn
Cædmon’s
Hymn
is a short Old English poem originally composed by Cædmon, in honour of God the Creator. It survives in a Latin translation by Bede in his
Historia ecclesiastica gentis Anglorum
and in vernacular versions written down in several manuscripts of Bede’s
Historia
.
Now [we] must honour the guardian of heaven,
the might of the architect, and his purpose,
the work of the father of glory
as he, the eternal lord, established the beginning of wonders;
he first created for the children of men
heaven as a roof, the holy creator
Then the guardian of mankind,
the eternal lord, afterwards
appointed the middle earth,
the lands for men, the Lord almighty.
| Old English | Latin (Bede) | Modern English Translation [1] |
|---|---|---|
| nu scylun hergan hefaenricaes uard | Nunc laudare debemus auctorem regni caelestis, | Now [we] must honour the guardian of heaven, |
| metudæs maecti end his modgidanc | potentiam creatoris, et consilium illius | the might of the architect, and his purpose, |
| uerc uuldurfadur swe he uundra gihwaes | facta Patris gloriae: quomodo ille,cum sit aeternus Deus, omnium | the work of the father of glory [2] as he, the eternal lord, established |
| eci dryctin or astelidæ | miraculorum auctor exstitit; | the beginning of wonders; |
| he aerist scop aelda barnu m | qui primo filiis hominum | he first created for the children of men [3] |
| heben til hrofe haleg scepen. | caelum pro culmine tecti | heaven as a roof, the holy creator |
| tha middungeard moncynnæs uard | dehinc terram custos humani generis | Then the guardian of mankind,the eternal lord, afterwards |
| eci dryctin æfter tiadæfirum fold u frea allmectig | generis creavit. omnipotens | appointed the middle earth,the lands for men, [4] the Lord almighty. |
-
Compare the recensional identifications for witnesses to the Old English Hymn in Dobbie (1937), The Manuscripts of Cæadmon’s Hymn and Bede’s Death Song, New York with those for manuscripts of the Latin Historia in Colgrave, B; Mynors, RAB, eds. (1969), Bede’s Ecclesiastical History of the English People, Oxford, pp. xxxix–lxx.
↵
-
This is the traditional translation of these lines, in agreement with Bede's Latin version. An alternative translation of the eorðanand aelda texts, however, understands weorc as the subject: "Now the works of the father of glory must honour the guardian of heaven, the might of the architect, and his mind's purpose."
↵
-
This is the reading of the West-Saxon ylda and Northumbrian aelda recensions. The West-Saxon eorðan, Northumbrian eordu, and with some corruption, the West-Saxon eorðe recensions would be translated "for the children of earth".
↵
-
The Northumbrian eordu and West-Saxon ylda and eorðe recensions would be translated "for men among the lands" at this point.
↵
CC licensed content, Shared previously
- Caedmon's Hymn. Provided by : Wikipedia. Located at : http://en.Wikipedia.org/wiki/C%C3%A6dmon%27s_Hymn . License : CC BY-SA: Attribution-ShareAlike


Stereotypes about people of in late adulthood lead many to assume that aging automatically brings poor health and mental decline. These stereotypes are reflected in everyday conversations, the media and even in greeting cards (Overstreet, 2006). The following examples serve to illustrate.
1) Grandpa, fishing pole in one hand, pipe in the other, sits on the ground and completes a story being told to his grandson with “. . . and that, Jimmy, is the tale of my very first colonoscopy.” The message inside the card reads, “Welcome to the gross personal story years.” (Shoebox, A Division of Hallmark Cards.)
2) An older woman in a barber shop cuts the hair of an older, dozing man. “So, what do you say today, Earl?” she asks. The inside message reads, “Welcome to the age where pretty much anyplace is a good place for a nap.” (Shoebox, A Division of Hallmark Cards.)
3) A crotchety old man with wire glasses, a crumpled hat, and a bow tie grimaces and the card reads, “Another year older? You’re at the age where you should start eatin’ right, exercisin’, and takin’ vitamins . . .” The inside reads, “Of course you’re also at the age where you can ignore advice by actin like you can’t hear it.” (Hallmark Cards, Inc.)
Of course, these cards are made because they are popular. Age is not revered in the United States, and so laughing about getting older is one way to get relief. The attitudes above are examples of ageism, prejudice based on age.
Ageism
is prejudice and discrimination that is directed at older people. This view suggests that older people are less in command of their mental faculties. Older people are viewed more negatively than younger people on a variety of traits, particularly those relating to general competence and attractiveness.
Stereotypes such as these can lead to a self-fulfilling prophecy in which beliefs about one’s ability results in actions that make it come true.
Ageism is a modern and predominately western cultural phenomenon—in the American colonial period, long life was an indication of virtue, and Asian and Native American societies view older people as wise, storehouses of information about the past, and deserving of respect. Many preindustrial societies observed
gerontocracy
, a type of social structure wherein the power is held by a society’s oldest members. In some countries today, the elderly still have influence and power and their vast knowledge is respected, but this reverence has decreased in many places due to social factors. A positive, optimistic outlook about aging and the impact one can have on improving health is essential to health and longevity. Removing societal stereotypes about aging and helping older adults reject those notions of aging is another way to promote health in older populations.
In addition to ageism, racism is yet another concern for minority populations as they age. The number of blacks above the age if 65 is projected to grow from around 4 million now to 12 million by 2060. Racism towards blacks and other minorities throughout the lifetime results in many older minorities having fewer resources, more chronic health conditions, and significant health disparities when compared
against
to older white Americans. Racism towards older adults from diverse backgrounds has resulted in
them having limited access to community resources such as grocery stores, housing, health care providers, and transportation.
[1]
Elderly Abuse
Nursing homes have been publicized as places where older adults are at risk of abuse. Abuse and neglect of nursing home residents is more often found in facilities that are run down and understaffed. However, older adults are more frequently abused by family members. The most commonly reported types of abuse are financial abuse and neglect. Victims are usually very frail and impaired and perpetrators are usually dependent on the victims for support. Prosecuting a family member who has financially abused a parent is very difficult. The victim may be reluctant to press charges and the court dockets are often very full resulting in long waits before a case is heard. “Granny dumping” or the practice of family members abandoning older family members with severe disabilities in emergency rooms is a growing problem; an estimated 100,000 and 200,000 are dumped each year (Tanne in Berk, 2007).
Watch It
This clip from the Big Think examines some of the negative prejudices about the elderly.
Modification, adaptation, and original content.
Authored by
: Sonja Ann Miller for Lumen Learning.
Provided by
: Lumen Learning.
License
:
CC BY: Attribution
Ageism in the USA: The paradox of prejudice against the elderly.
Authored by
: Ashton Applewhite.
Provided by
: Big Think.
Located at
:
https://www.youtube.com/watch?v=oX3Lw5JMRi4
.
License
:
Other
.
License Terms
: Standard YouTube License


3.7: Changing data- basics of transformations
In complicated studies involving many data types: measurements and ranks, percentages and counts, parametric, nonparametric and nominal, it is useful to unify them. Sometimes such transformations are easy. Even nominal data may be understood as continuous, given enough information. For example, sex may be recorded as continuous variable of blood testosterone level, possibly with additional measurements. Another, more common way, is to treat discrete data as continuous—it is usually safe, but sometimes may lead to unpleasant surprises.
Another possibility is to transform measurement data into ranked. R function cut() allows to perform this operation and create ordered factors.
What is completely unacceptable is transforming common nominal data into ranks. If values are not, by their nature, ordered, imposing an artificial order can make the results meaningless.
Data are often transformed to make them closer to parametric and to homogenize standard deviations. Distributions with long tails, or only somewhat bell-shaped (as in Figure 4.2.5), might be log-transformed . It is perhaps the most common transformation.
There is even a special argument plot(..., log="axis") , where "axis" should be substituted with x or y , presenting it in (natural) logarithmic scale. Another variant is to simply calculate logarithm on the fly like plot(log(...) .
Consider some widely used transformations and their implications in R (we assume that your measurements are recorded in the vector data ):
- Logarithmic: log(data + 1) . It may normalize distributions with positive skew (right-tailed), bring relationships between variables closer to linear and equalize variances. It cannot handle zeros, this is why we added a single digit.
- Square root: sqrt(data) . It is similar to logarithmic in its effects, but cannot handle negatives.
- Inverse: 1/(data + 1) . This one stabilizes variances, cannot handle zeros.
- Square: data^2 . Together with square root, belongs to family of power transformations . It may normalize data with negative skew (left-tailed) data, bring relationships between variables closer to linear and equalize variances.
- Logit: log(p/(1-p)) . It is mostly used on proportions to linearize S-shaped, or sigmoid, curves. Along with logit, these types of data are sometimes treated with arcsine transformation which is asin(sqrt(p)) . In both cases, p must be between 0 and 1.
While working with multiple variables, keep track of their dimensions. Try not to mix them up, recording one variable in millimeters, and another in centimeters. Nevertheless, in multivariate statistics even data measured in common units might have different nature. In this case, variables are often standardized , e.g. brought to the same mean and/or the same variance with scale() function. Embedded trees data is a good example:
Code \(\PageIndex{1}\) (R):
At the end of data types explanation, we recommend to review a small chart which could be helpful for the determination of data type (Figure \(\PageIndex{1}\)).