15.5: Projective transformations
A bijection from the real projective plane to itself that sends lines to lines is called projective transformation .
Note that any affine transformation defines a projective transformation on the corresponding real projective plane. We will call such projective transformations affine ; these are projective transformations that send the ideal line to itself.
The extended perspective projection discussed in the previous section provides another source of examples of projective transformations.
Given a line \(\ell\) in the real projective plane, there is a perspective projection that sends \(\ell\) to the ideal line.
Moreover, a perspective transformation is either affine or, in a suitable coordinate system, it can be written as a composition of the extension of perspective projection
\(\beta:(x,y) \mapsto (\dfrac{x}{y},\dfrac{1}{y})\)
and an affine transformation.
- Proof
-
We may choose an \((x,y)\) -coordinate system such that the line \(\ell\) is defined by equation \(y=0\) . Then the extension of \(\beta\) gives the needed transformation.
Fix a projective transformation \(\gamma\) . If \(\gamma\) sends the ideal line to itself, then it has to be affine. It proves the theorem in this case.
Suppose \(\gamma\) sends the ideal line to a line \(\ell\) . Choose a perspective projection \(\beta\) as above. The composition \(\beta\circ\gamma\) sends the ideal line to itself. That is, \(\gamma=\beta\circ\gamma\) is affine. Note that \(\beta\) is self-inverse; therefore \(\alpha=\beta\circ \gamma\) — hence the result.
Let \(P\mapsto P'\) be (a) an affine transformation, (b) the perspective projection defined by \((x,y) \mapsto (\dfrac{x}{y},\dfrac{1}{y})\) , or (c) arbitrary projective transformation. Suppose \(P_1,P_2,P_3,P_4\) lie on one line. Show that
\(\dfrac{P_1P_2\cdot P_3P_4}{P_2 P_3 \cdot P_4 P_1}=\dfrac{P'_1P'_2\cdot P'_3P'_4}{P'_2P'_3\cdot P'_4P'_1};\)
that is, each of these maps preserves cross ratio for quadruples of points on one line.
- Hint
-
To prove (a), apply Proposition 14.3.1 .
To prove (b), suppose \(P_i = (x_i, y_i)\); show and use that
\(\dfrac{P_1 P_2 \cdot P_3P_4}{P_2P_3 \cdot P_4P_1} = |\dfrac{(x_1 - x_2) \cdot (x_3 - x_4)}{(x_2 - x_3)\cdot (x_4 - x_1)}|\)
if all \(P_i\) lie on a horizontal line \(y = b\), and
\(\dfrac{P_1 P_2 \cdot P_3P_4}{P_2P_3 \cdot P_4P_1} = |\dfrac{(y_1 - y_2) \cdot (y_3 - y_4)}{(y_2 - y_3)\cdot (y_4 - y_1)}|\)
otherwise. (See 20.8.4 for another proof.)
To prove (c), apply (a), (b), and Theorem \(\PageIndex{1}\).


7.12: Review- Networks and Security Jeopardy
A Jeopardy game is attached to assist you in your review. You will need the PowerPoint application or a PowerPoint viewer to play the game. You can perform these exercises on your mobile devices with access to Office 365 Mobile or a separate App for your Apple or Android device.
Jeopardy: Networks and Security Review
NOTE: The Jeopardy Game should open in the Slide Show view and be immediately playable. If it opens in the regular PowerPoint presentation view, go to the SLIDE SHOW tab on the ribbon and start the show from THE BEGINNING (command on the far left). You can play the game as many times as you like and in any order you like.
- Introduction to Computer Applications and Concepts. Authored by : Jim Shannon. Provided by : Extended Learning Institute of Northern Virginia Community College. Located at : http://www.nvcc.edu/eli/index.html . License : CC BY: Attribution


3.8: The Long Zhou Dynasty (1046BCE)
- 132253
After the Xia and Shang, the next major dynasty in Chinese history is the Zhou Dynasty (1045 – 256 BCE). In 1046 BCE, a Zhou king overthrew the last Shang ruler and established control over much of north China. During the Western Zhou (1046 – 771 BCE), Zhou kings dispatched kinsmen to territories he granted to them (see Map \(\PageIndex{1}\)). These nobles were allowed to rule their own lands hereditarily, so long as they observed certain obligations to their king.
Over time, Zhou kings lost their ability to control these lords, and the lords became increasingly independent. In 771 BCE, in what became a telling sign of weakness, the Zhou king was murdered and his young successor was compelled to relocate farther east, to a capital closer to the heart of the North China Plain. This move marked the beginning of the Eastern Zhou (770 – 256 BCE). Over a half millennium, Zhou nobility engaged in escalating warfare with each other over matters small and large. As they did so, their lands evolved into powerful states (see Map \(\PageIndex{2}\)). Eventually, the noble lords of the most powerful states declared themselves as kings, and fought to gain control over all of China. During the third century BCE, the Zhou Kingdom was destroyed and one of these warring states, the Qin [Cheen] Dynasty , prevailed over the rest.
But these centuries were not only marked by the growth of states and accelerating warfare between them. Burgeoning turmoil also inspired much thinking about what was needful to restore order and create a good society, as well as what defined the good life. Two major philosophical traditions emerged to address these issues: Confucianism and Daoism .
3.4.1: The Western Zhou Dynasty (1046 – 771 BCE)
In the eleventh century BCE, the Zhou state was a minor power on the western periphery of the Shang realm, located along the Wei [way] River. In 1059, upon witnessing five planets align, the Zhou ruler declared himself king and proceeded to engage in military conquests that made his kingdom a regional power. King Wen (“Cultured King”) was this ruler, and revered as the founder of the Zhou dynasty. But it was his son King Wu (“Martial King”) who brought down the Shang Dynasty. In 1046, with three-hundred chariots and 45,000 foot soldiers equipped with bronze armor and pole-mounted dagger-axes, he met and decisively defeated the last Shang king and his army.
Then, King Wu returned to his capital in the Wei River Valley, where he passed away in 1043 BCE. His young son took the throne, but was placed under the regency of Wu’s capable brother, the Duke of Zhou. Now, the Zhou royal court was faced with the task of governing newly conquered territory, including the former lands of the Shang Dynasty. The king and his regent did so by implementing three policies.
- First, they established a secondary capital farther east at Luoyang [low-yawng], closer to the North China Plain.
- Second, they issued proclamations explaining to conquered peoples why they should accept Zhou rule. According to the Duke of Zhou, Heaven had decreed that Shang kings must fall and Zhou rulers should replace them. The Shang dynasty had begun with wise and benevolent rulers, but later kings were cruel and incompetent, and failed to see to the well-being of their subjects. Thus, the dynasty had lost this sanction. This political theory, which is known as the Mandate of Heaven , would also be used by founders of later dynasties to justify their actions, as well as by theorists to explain the rise and fall of dynasties.
- The third policy was to dispatch royal kinsmen to strategically critical locations for the purpose of establishing colonies. At their royal palaces, Zhou kings conducted ceremonies of investiture during which they sacrificed to Heaven and the spirits of deceased ancestors, held banquets, and then bestowed noble titles and grants of land upon members of the royal family and relatives by marriage. Large bronzes were cast to commemorate these occasions (see Figure \(\PageIndex{1}\)). These kinsmen took their families, contingents of soldiers, and emblems of nobility to the granted territory and set up palaces and ancestral temples in walled towns. From there, they governed a predominantly rural population of farmers living in villages where life was not easy. Living in hovels and with little opportunity to leave their lord’s manors, these farmers were required to work his lands and also to submit a portion of the harvest from their own small farms.
Historians call this method of governing Zhou kinship feudalism . Feudalism is generally a political and economic system characterized by fragmented authority, a set of obligations (usually of a military nature) between lords and vassals, and grants of land (“fiefs”) by rulers in exchange for some type of service. Indeed, Zhou kings granted land and noble titles to kinsmen in exchange for obedience, periodic visits to the king’s palace, tribute, and military support. However, aside from the presence of royal overseers, a hereditary lord enjoyed relative sovereignty in his own domain. The glue that held the Zhou feudal order together was deference to the king and his Mandate and reverence for their shared history–including, most importantly, the deceased spirits of their related ancestors.
Over time, Zhou kings’ ability to control the noble lords diminished over time, and their prestige suffered accordingly. There were two principal reasons for this.
- Over time, ties of kinship lost their meaning. In later generations, lords simply became more interested in and identified with their own territories, and they had little sense of solidarity with distant cousins ruling neighboring feudal states. Hence, it is hardly surprising that many lords ceased to pay visits to the king’s court.
- Second, Zhou kings were unable to impose their will on feuding feudal lords and were even defeated by them in several military campaigns. For example, in 771 BCE, King You [yo] was attacked by the allied forces of the lord of Shen and tribal peoples residing out west. The capital was sacked, and he was killed. Other states came to the rescue, relocating the king’s son, Prince Ping, to the eastern capital at Luoyang. Zhou kings remained there for the next five hundred years, during the period called the Eastern Zhou.
3.4.2: The Eastern Zhou Dynasty (770 – 256 BCE) and the Warring States Period (c. 475 – 221 BCE)
Relocated to Luoyang, King Ping ruled from a much smaller royal domain surrounded by approximately 150 feudal states and their lords. No longer able to impose their will on unruly noble lineages, Zhou kings failed to maintain a semblance of peace and order throughout the realm. Instead, this warrior nobility engaged in an escalating contest for power and prestige.
After 540 wars were fought over two centuries, only fifteen states remained by 475 BCE (see Map \(\PageIndex{2}\)). But they fought even more fiercely. Over the next 250 years, during what is referred to as the Warring States Period (475 – 221 BCE), these states averaged one major battle per year until, at the very end, only the state of Qin [cheen] remained. (The line of Zhou kings had, however, already been extinguished in 256 BCE, so that date marks the end of the Eastern Zhou Dynasty.)
As the frequency and scale of warfare escalated, and states gradually gobbled each other up, the way feudal lords governed their states and conducted military campaigns changed. Prior to the Warring States Period, Zhou kings were still accorded a level of respect, at least as symbols of unity and nominal heads of the Zhou feudal order. At this point, the many lords had no intention of toppling the king; rather, seeing his military weakness, the most powerful ones stepped in to enforce order. The first was Duke Huan of Qi [who-an of chee]. He held this title (“duke”) and fief (Qi) because his distant ancestor had served as a commander under King Wu during the Zhou founding. Now, many generations later, his state was a formidable power on the east coast. In 651 BCE, he convened an interstate meeting with other lords to discuss matters of order and security. Upon being elected as their leader, the Zhou king conferred the title of hegemon . In this capacity, Duke Huan had the authority to resolve disputes between nobles on behalf of the king.
Over the next two centuries, this title changed hands several times. These hegemons periodically convened interstate meetings to manage such matters as misbehaving states or foreign invasions.  Yet, although hegemons maintained a semblance of order, warfare remained constant because it was a way of life for the illustrious lineages of the Zhou realm.
Noble lords loved to demonstrate their prowess and raise their prestige through success in hunting and battling. A noble looked for a pretext to engage in a vendetta with another lord, at which point a battle was arranged and then carried out according to the protocols of chivalry. After announcing the impending campaign at the ancestral temple, a lord and his kinsmen, accompanied by farmer foot soldiers, would proceed in their chariots to a prearranged location and engage in a skirmish. In victory, a noble redressed matters of honor and brought glory to his ancestors, something symbolized by the mound of dead enemies placed by his ancestral temple.
However, with the onset of the Warring States Period in the fifth century BCE, the level of violence was no longer contained by the hegemon system and codes of chivalry. Both the purpose and conduct of warfare changed. Lords of the seven most powerful states lost respect for the Zhou kings and even assumed the same title, thus claiming the right to unify all of China under their rule. As opposed to serving a lesson to and resolving some dispute with another lord, these self-declared kings waged war to destroy them and take their land.
During the Warring States, rulers introduced large armies composed of mass infantry and cavalry. Soldiers were equipped with armor, crossbows, halberds, dagger-axes, and swords manufactured from bronze, iron, leather, and wood in royal workshops located at capital cities. (View the image of a Warring States Period soldier at the following link: http://brandonqindynasty.weebly.com/...9/8580061.jpeg .
Kings also militarized their kingdoms’ landscapes by building forts at strategically critical passes, walls to mark off boundaries, and watchtowers to signal the enemy’s approach. Finally, these rulers no longer relied solely on close kinsmen to wage war alongside them. Rather, they created a class of military commanders and specialists whose promotion was based on their ability to produce victories in the field.
During this time, some of China’s greatest military treatises were written, most notably the Art of War by Master Sun [sue-in]. Master Sun was a military commander and strategist who served the lords of the state of Wu just prior to the onset of the Warring States period (c. fifth century BCE). This manual of military strategy and tactics stresses the importance of formulating a strategy that ensures victory prior to any campaigning. Stratagem is critical. “All warfare is deception,” Master Sun states. “Hence, when able to attack, we must seem unable; when using our forces, we must seem inactive; when we are near, we must make the enemy believe we are far away; when far away, we must make him believe we are near.”
Prior to the Warring States Period, it was the norm for nobility to hand out land in their states to kinsmen, just as it had been for the king during the Western Zhou. This practice meant that lesser but related aristocratic lineages lived in estates across each noble’s territory, while also serving as ministers at his court. For a king, however, these men might become an obstacle or pose a threat because they held this land hereditarily. Therefore, they devised better ways to control land in their realms.
Whenever new territory was added or a noble line was extinguished, kings created counties and appointed magistrates to manage the villages and towns in that area. The magistrate’s job would be to register the population, maintain law and order, collect tax revenue, and conscript people for labor projects and military campaigns. Rather than give those posts to kinsmen, kings appointed men from the lower ranks of the nobility or commoners based on their loyalty and merit.
Stated more simply, Warring States Period rulers created administrative units and a civil service. Their embryonic bureaucracies included such features as a system of official posts, salaries paid in grain and gifts, administrative codes, and methods for measuring a servant’s performance. By the end of this period, largely owing to the demands of warfare, the Zhou feudal order had been supplanted by a small number of powerful territorial states with centralized monarchies. Among them, the most successful was the state of Qin , which eventually conquered all of China and became an empire. We return to that topic after reviewing the ideas put forward by philosophers in the context of these centuries of turmoil.
3.4.3: Philosophy in a Time of Turmoil: Confucianism and Daoism
China’s three major pre-modern philosophical and religious traditions are Confucianism, Daoism, and Buddhism. The first two had their origins in the later centuries of the Eastern Zhou, while Buddhism only began to arrive from South Asia in the first century C.E. Confucianism and Daoism were both responses to the crisis presented by the breakdown of the Zhou feudal order and escalating warfare in China.
<IP_ADDRESS>: Confucius and Confucianism
Confucius lived just prior to the Warring States Period (551-479 BCE). What little we know about his life comes primarily from the Analects , a record of conversations Confucius held with his students compiled after he died. In later centuries, in China, Confucius was revered as a sage and teacher. In the context of his time, Confucius was a dynamic individual who believed he was mandated by Heaven to return the world to a more socially and politically harmonious time. The Analects not only shows a serious and learned man, but also someone capable in archery and horsemanship, who loved music and ritual, and who untiringly traveled the feudal states in the hopes of serving in a lord’s retinue (see Figure \(\PageIndex{2}\)). According to one passage, a lord once asked one of Confucius’s students about his master, but the student fell silent. Later, Confucius asked him, “Why did you not say: As a man, when agitated in thought he forgets to eat, joyfully forgetting his cares, not realizing that old age is near at hand?”
Confucius was born to a family of minor nobility and modest means in the feudal state of Lu. His father died about the time Confucius was born, and he was raised by his mother, who also passed away when Confucius was young. Like other young men of similar background, he had access to education and could aspire to serve in some capacity in a feudal state, perhaps at the lord’s court, or as an official or soldier.
Confucius chose to become learned and seek office. To his mind, he was living at a time when civilization was collapsing and society was decaying. He believed that the nobility was honorable, observed moral codes, and upheld social standards. He thought that a golden age existed in the past and wished to transmit the ethical values of that time. However, in the course of doing so, he reinterpreted the past and imbued the virtues he stressed with rich, new meanings. Here are a few of the important statements Confucius made, and what they meant:
1. “The noble person is concerned with rightness, the small person is concerned with profit.” (4.16) Confucius redefined the meaning of nobility. For him, nobility was defined not by birth but rather by character and conduct. A truly noble person is one who puts what is right before personal gain and the desire for wealth and fame.
2. “Young men should be filial at home and respectful to their elders when away from home.” (1.6) Filial piety is central to Confucius’s thought. He taught how a person becomes moral because a good society only develops when composed of and led by virtuous people. He saw the practice of morality in the family as the root. Should a young man learn to be respectful and reverent towards parents and elders, he will become a humane person, and humane people are far more likely to contribute in a positive way to society.
3. “The noble man does not abandon humaneness for so much as the space of a meal.” (4.5) For Confucius, the highest virtue is humanity, and many of his conversations center upon defining what it is that makes a person humane. A person of humanity is, for instance, one who is capable of empathy and unselfish concern for the welfare of others. They know the golden rule: “what you would not want for yourself,” he taught, “do not do to others.” (15.23) Confucius emphasized that a society cannot function if people are incapable of taking others’ perspectives and doing their best for them. In addition, he insisted that such virtues as humanity are most fully demonstrated when individuals observe good etiquette. Decorum was important to Confucius.
4. “Heaven has given birth to the virtue that is in me.” 1 (7.22) Interpreters of Confucius have rightly noted that he is quite silent about the supernatural and what happens after death, rather emphasizing the life we have and serving others. Yet, it would be wrong to conclude that he wasn’t religious in any sense, because he frequently spoke of Heaven. He believed that Heaven ordains a certain course of life for each individual, including becoming a moral person. This Heaven is less a deity than a higher moral order, a kind of beneficent presence.
5. “To govern is to rectify. If you lead the people by being rectified yourself, who will dare not be rectified?” (12.17) Confucius believed that good governing flows from good men. The first qualification for a ruler or one who serves is moral rectitude. If those who lead do so by virtue and conduct themselves according to rules of propriety, people will learn from them and develop a sense of honor and shame. Consequently, society will become more orderly.
The noble person, filial piety, humaneness, etiquette, Heaven, and government by men of virtue are just some of the ideas Confucius discussed as he traveled the feudal states seeking to advise their lords. However, he only managed to hold some minor offices in Lu and generally failed in his political aspirations. Instead, he gained an avid following of 70 students, whom he accepted regardless of their social status. After he died, they passed on his teachings, and a school of thought emerged from his teachings known as Confucianism. Those who belonged to it are Confucians –individuals distinguished by their commitment to the ideas articulated by Confucius, classical learning, and the value they place on character and conduct as the key to a good society and political order.
<IP_ADDRESS>: Philosophical and Institutional Daoism
During the turmoil of the Warring States period, other individuals developed a philosophy very different from Confucianism called Daoism. These Daoists largely rejected Confucian ideas about human moral development and social order as artificial constructs. Rather, they pointed to a natural condition that both individuals and society can recover, one that existed before desires trapped people in a world of strife. Their central concept is the Dao (“Way”). The Dao is mysterious: it is beyond sense-perception and yet the source of life and the universe, the ultimate truth transcending the polarities that make up life and yet pervades them, empty and yet the mother of all things.
Paradoxically, although the Dao is indescribable and can’t be seen or heard, the goal of the Daoist is to accord with and follow it. But this goal won’t be accomplished through more seeking and more knowledge. Rather, the mind must be emptied out, calmed, and purified, until desires are absent and a primordial, natural condition is restored. At that point, when the individual is in accord with the ineffable Way, life becomes spontaneous, natural, and effortless.
The two most important early books belonging to this tradition are: the Laozi (“Old Master”) and Zhuangzi (“Master Zhuang”). Historians believe the “Old Master” was a fictional sage invented by Warring States Period philosophers who compiled the book attributed to him. Master Zhuang, however, lived during the fourth century BCE.
In later centuries, the Daoism of these early philosophers was taken in new directions. The definition of the Way was broadened to include the idea that individuals have a spiritual essence in need of harmonizing and liberation. By so doing, one’s health would be preserved and life prolonged. Daoists even entertained the idea that one could become immortal. To achieve these goals, techniques were developed, including special dietary regimens, yoga, Chinese boxing, meditation, and alchemy.
Over the course of the first millennium CE, Daoism became a popular and institutionalized religion. Daoist masters, claiming divine inspiration, composed esoteric texts for their followers that explained how the natural world originated from a primordial ether ( qi ) and its division into two polar forces: the yin and yang (see Figure \(\PageIndex{3}\)). They presented a universe with multiple heavenly and hellish realms populated with divinities and demons. The principal purpose of these Daoists was to attend to a person’s physical and psychological well-being. That involved not only teaching individual techniques for preserving the life spirit, but included the use of exorcism and faith healing to remove malevolent influences. Daoists developed communal prayers and rituals that could cure illness, free souls from hell, win blessings from heaven, and eliminate sins from the community. Eventually, a Daoist church developed, with its own ordained priesthood, temples, and monasteries.
1 These selections from the Analects are translated in De Bary and Bloom, ed., Sources of Chinese Tradition, Vol. 1: From Earliest Times to the Present, 44-63.


4.4: Age Related Changes to the Integumentary System
Aging and the Integumentary System
All systems in the body accumulate subtle and some not-so-subtle changes as a person ages. Among these changes are reductions in cell division, metabolic activity, blood circulation, hormonal levels, and muscle strength (Figure 4.17). In the skin, these changes are reflected in decreased mitosis in the stratum basale, leading to a thinner epidermis. The dermis, which is responsible for the elasticity and resilience of the skin, exhibits a reduced ability to regenerate, which leads to slower wound healing. The hypodermis, with its fat stores, loses structure due to the reduction and redistribution of fat, which in turn contributes to the thinning and sagging of skin.
The accessory structures also have lowered activity, generating thinner hair and nails, and reduced amounts of sebum and sweat. A reduced sweating ability can cause some elderly to be intolerant to extreme heat. Other cells in the skin, such as melanocytes and dendritic cells, also become less active, leading to a paler skin tone and lowered immunity. Wrinkling of the skin occurs due to breakdown of its structure, which results from decreased collagen and elastin production in the dermis, weakening of muscles lying under the skin, and the inability of the skin to retain adequate moisture.
Many anti-aging products can be found in stores today. In general, these products try to rehydrate the skin and thereby fill out the wrinkles, and some stimulate skin growth using hormones and growth factors. Additionally, invasive techniques include collagen injections to plump the tissue and injections of BOTOX ® (the name brand of the botulinum neurotoxin) that paralyze the muscles that crease the skin and cause wrinkling.
Contributors and Attributions
- Chapter 5. Authored by : OpenStax College. Provided by : Rice University. Located at : http://cnx.org/contents/14fb4ad7-39a1-4eee-ab6e-3ef2482e3e22<EMAIL_ADDRESS>. Project : AtD Course. License : CC BY: Attribution


7.18E: The AraC Regulator
The L-arabinose operon, also called ara operon, encodes enzymes needed for the catabolism of arabinose to xylulose 5-phosphate.
LEARNING OBJECTIVES
Describe the regulatory mechanism of the AraC protein in the presence and absence of arabinose
Key Takeaways
Key Points
- The structural gene, which encodes arabinose breakdown enzymes, is araBAD.
- The ara operon is regulated by the AraC protein.
- When arabinose is present, arabinose binds AraC and prevents it from interacting.
Key Terms
- operon : A unit of genetic material that functions in a coordinated manner by means of an operator, a promoter, and structural genes that are transcribed together.
- L-arabinose : Arabinose is an aldopentose – a monosaccharide containing five carbon atoms, and including an aldehyde (CHO) functional group.
- catabolism : Destructive metabolism, usually includes the release of energy and breakdown of materials.
The L-arabinose operon, also called ara operon, is a gene sequence encoding enzymes needed for the catabolism of arabinose to xylulose 5-phosphate, an intermediate of the pentose phosphate pathway. It has both positive and negative regulation. The operon is found in Escherichia coli ( E. coli ).
It has been a focus for research in molecular biology since 1970, and has been investigated extensively at its genetic, biochemical, physiological, and biophysical levels.
The structural gene, which encodes arabinose breakdown enzymes, is araBAD. The regulator gene is araC. The genes, araBAD and araC, are transcribed in opposite directions.
The operators are araI and araO2. The operators lie between the AraC.
AraI lies between the structural genes and the operator. The araI1 and araI2 are DNA -binding sites that, when occupied by AraC, induce expression.
Sequence of the Operon: 5′—–araC—–araO—–araI—–araB—–araA—–araD—–3′
The ara operon is regulated by the AraC protein. If arabinose is absent, the dimer AraC protein represses the structural gene by binding to araI1 and araO2 and the DNA forms a loop, which prevents RNA polymerase from binding to the promoter of the ara operon, thereby blocking transcription.
When arabinose is present, arabinose binds AraC and prevents it from interacting. This breaks the DNA loop. The two AraC-arabinose complexes bind to the araI site which promotes transcription. When arabinose is present, AraC acts as an activator and it builds a complex: AraC + arabinose. This complex is needed for RNA polymerase to bind to the promoter and transcribe the ara operon.
Also for activation, the binding of another structure to araI is needed: CRP (formerly known as CAP) + cyclic AMP. Thus the activation depends on the presence of arabinose and cAMP.
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- transcription. Provided by : Wiktionary. Located at : en.wiktionary.org/wiki/transcription. License : CC BY-SA: Attribution-ShareAlike
- gene. Provided by : Wiktionary. Located at : en.wiktionary.org/wiki/gene. License : CC BY-SA: Attribution-ShareAlike
- anabolic pathways. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/anabolic%20pathways. License : CC BY-SA: Attribution-ShareAlike
- OpenStax College, Prokaryotic Gene Regulation. October 16, 2013. Provided by : OpenStax CNX. Located at : http://cnx.org/content/m44535/latest/Figure_16_02_01.jpg . License : CC BY: Attribution
- AminoAcidball. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/File:AminoAcidball.svg. License : Public Domain: No Known Copyright
- LacI Dimer Structure Annotated. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/File:LacI_Dimer_Structure_Annotated.png. License : CC BY-SA: Attribution-ShareAlike
- TrpR. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/File:TrpR.jpg. License : CC BY-SA: Attribution-ShareAlike
- L-arabinose operon. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/L-arabinose_operon. License : CC BY-SA: Attribution-ShareAlike
- catabolism. Provided by : Wiktionary. Located at : en.wiktionary.org/wiki/catabolism. License : CC BY-SA: Attribution-ShareAlike
- operon. Provided by : Wiktionary. Located at : en.wiktionary.org/wiki/operon. License : CC BY-SA: Attribution-ShareAlike
- L-arabinose. Provided by : Wiktionary. Located at : en.wiktionary.org/wiki/L-arabinose. License : CC BY-SA: Attribution-ShareAlike
- OpenStax College, Prokaryotic Gene Regulation. October 16, 2013. Provided by : OpenStax CNX. Located at : http://cnx.org/content/m44535/latest/Figure_16_02_01.jpg . License : CC BY: Attribution
- AminoAcidball. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/File:AminoAcidball.svg. License : Public Domain: No Known Copyright
- LacI Dimer Structure Annotated. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/File:LacI_Dimer_Structure_Annotated.png. License : CC BY-SA: Attribution-ShareAlike
- TrpR. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/File:TrpR.jpg. License : CC BY-SA: Attribution-ShareAlike
- DL-Arabinose. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/File:DL-Arabinose.svg. License : Public Domain: No Known Copyright


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actinide series
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(also, actinoid series) actinium and the elements in the second row or the
f
-block, atomic numbers 89–103
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bidentate ligand
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ligand that coordinates to one central metal through coordinate bonds from two different atoms
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central metal
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ion or atom to which one or more ligands is attached through coordinate covalent bonds
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chelate
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complex formed from a polydentate ligand attached to a central metal
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chelating ligand
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ligand that attaches to a central metal ion by bonds from two or more donor atoms
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cis
configuration
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configuration of a geometrical isomer in which two similar groups are on the same side of an imaginary reference line on the molecule
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coordination compound
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stable compound in which the central metal atom or ion acts as a Lewis acid and accepts one or more pairs of electrons
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coordination compound
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substance consisting of atoms, molecules, or ions attached to a central atom through Lewis acid-base interactions
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coordination number
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number of coordinate covalent bonds to the central metal atom in a complex or the number of closest contacts to an atom in a crystalline form
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coordination sphere
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central metal atom or ion plus the attached ligands of a complex
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crystal field splitting (Δ
oct
)
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difference in energy between the
t
2
g
and
e
g
sets or
t
and
e
sets of orbitals
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crystal field theory
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model that explains the energies of the orbitals in transition metals in terms of electrostatic interactions with the ligands but does not include metal ligand bonding
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d
-block element
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one of the elements in groups 3–11 with valence electrons in
d
orbitals
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donor atom
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atom in a ligand with a lone pair of electrons that forms a coordinate covalent bond to a central metal
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e
g
orbitals
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set of two
d
orbitals that are oriented on the Cartesian axes for coordination complexes; in octahedral complexes, they are higher in energy than the
t
2
g
orbitals
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f
-block element
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(also, inner transition element) one of the elements with atomic numbers 58–71 or 90–103 that have valence electrons in
f
orbitals; they are frequently shown offset below the periodic table
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first transition series
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transition elements in the fourth period of the periodic table (first row of the
d
-block), atomic numbers 21–29
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fourth transition series
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transition elements in the seventh period of the periodic table (fourth row of the
d
-block), atomic numbers 89 and 104–111
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geometric isomers
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isomers that differ in the way in which atoms are oriented in space relative to each other, leading to different physical and chemical properties
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high-spin complex
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complex in which the electrons maximize the total electron spin by singly populating all of the orbitals before pairing two electrons into the lower-energy orbitals
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hydrometallurgy
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process in which a metal is separated from a mixture by first converting it into soluble ions, extracting the ions, and then reducing the ions to precipitate the pure metal
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ionization isomer
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(or coordination isomer) isomer in which an anionic ligand is replaced by the counter ion in the inner coordination sphere
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lanthanide series
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(also, lanthanoid series) lanthanum and the elements in the first row or the
f
-block, atomic numbers 57–71
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ligand
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ion or neutral molecule attached to the central metal ion in a coordination compound
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linkage isomer
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coordination compound that possesses a ligand that can bind to the transition metal in two different ways (CN
−
vs. NC
−
)
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low-spin complex
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complex in which the electrons minimize the total electron spin by pairing in the lower-energy orbitals before populating the higher-energy orbitals
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monodentate
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ligand that attaches to a central metal through just one coordinate covalent bond
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optical isomer
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(also, enantiomer) molecule that is a nonsuperimposable mirror image with identical chemical and physical properties, except when it reacts with other optical isomers
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pairing energy (P)
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energy required to place two electrons with opposite spins into a single orbital
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platinum metals
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group of six transition metals consisting of ruthenium, osmium, rhodium, iridium, palladium, and platinum that tend to occur in the same minerals and demonstrate similar chemical properties
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polydentate ligand
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ligand that is attached to a central metal ion by bonds from two or more donor atoms, named with prefixes specifying how many donors are present (e.g., hexadentate = six coordinate bonds formed)
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rare earth element
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collection of 17 elements including the lanthanides, scandium, and yttrium that often occur together and have similar chemical properties, making separation difficult
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second transition series
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transition elements in the fifth period of the periodic table (second row of the
d
-block), atomic numbers 39–47
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smelting
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process of extracting a pure metal from a molten ore
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spectrochemical series
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ranking of ligands according to the magnitude of the crystal field splitting they induce
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steel
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material made from iron by removing impurities in the iron and adding substances that produce alloys with properties suitable for specific uses
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strong-field ligand
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ligand that causes larger crystal field splittings
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superconductor
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material that conducts electricity with no resistance
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t
2
g
orbitals
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set of three
d
orbitals aligned between the Cartesian axes for coordination complexes; in octahedral complexes, they are lowered in energy compared to the
e
g
orbitals according to CFT
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third transition series
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transition elements in the sixth period of the periodic table (third row of the
d
-block), atomic numbers 57 and 72–79
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trans
configuration
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configuration of a geometrical isomer in which two similar groups are on opposite sides of an imaginary reference line on the molecule
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weak-field ligand
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ligand that causes small crystal field splittings
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12.13.6: Findable
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- Save as PDF
Findable
The “Internet of Things” refers to the idea of physical objects being connected to the Internet. Advances in wireless technologies and sensors will allow physical objects to send and receive data about themselves. Many of the technologies to enable this are already available – it is just a matter of integrating them together.
In a 2010 report by McKinsey & Company on the Internet of Things [13] , six broad applications are identified:
- Tracking behavior. When products are embedded with sensors, companies can track the movements of these products and even monitor interactions with them. Business models can be fine-tuned to take advantage of this behavioral data. Some insurance companies, for example, are offering to install location sensors in customers’ cars. That allows these companies to base the price of policies on how a car is driven as well as where it travels.
- Enhanced situational awareness. Data from large numbers of sensors deployed, for example, in infrastructure (such as roads and buildings), or to report on environmental conditions (including soil moisture, ocean currents, or weather), can give decision makers a heightened awareness of real-time events, particularly when the sensors are used with advanced display or visualization technologies. Security personnel, for instance, can use sensor networks that combine video, audio, and vibration detectors to spot unauthorized individuals who enter restricted areas.
- Sensor-driven decision analysis. The Internet of Things also can support longer-range, more complex human planning and decision making. The technology requirements – tremendous storage and computing resources linked with advanced software systems that generate a variety of graphical displays for analyzing data – rise accordingly.
- Process optimization. Some industries, such as chemical production, are installing legions of sensors to bring much greater granularity to monitoring. These sensors feed data to computers, which in turn analyze the data and then send signals to actuators that adjust processes – for example, by modifying ingredient mixtures, temperatures, or pressures.
- Optimized resource consumption. Networked sensors and automated feedback mechanisms can change usage patterns for scarce resources, such as energy and water. This can be accomplished by dynamically changing the price of these goods to increase or reduce demand.
- Complex autonomous systems. The most demanding use of the Internet of Things involves the rapid, real-time sensing of unpredictable conditions and instantaneous responses guided by automated systems. This kind of machine decision-making mimics human reactions, though at vastly enhanced performance levels. The automobile industry, for instance, is stepping up the development of systems that can detect imminent collisions and take evasive action.


6.3.3: Nucleophilic and Electrophilic Addition and Abstraction
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Learning Objectives
In this lecture you will learn the following
- Ligand activation by metal that leads to a direct external attack at the ligand.
- Nucleophilic addition and nucleophilic abstraction reactions.
- Electrophilic addition and electrophilic abstraction reactions.
The nucleophilic and electrophilic substitution and abstraction reactions can be viewed as ways of activation of substrates to allow an external reagent to directly attack the metal activated ligand without requiring prior binding of the external reagent to the metal. The attacking reagent may be a nucleophile or an electrophile. The nucleophilic attack of the external reagent is favored if the L n M fragment is a poor π−base and a good σ−acid i . e ., when the complex is cationic and/or when the other metal bound ligands are electron withdrawing such that the ligand getting activated gets depleted of electron density and can undergo an external attack by a nucleophile Nu − , like LiMe or OH − . The attack of the nucleophiles may result in the formation of a bond between the nucleophiles and the activated unsaturated substrate, in which case it is called nucleophilic addition, or may result in an abstraction of a part or the whole of the activated ligand, in which case it is called the nucleophilic abstraction. The nucleophilic addition and the abstraction reactions are discussed below.
Nucleophilic addition
An example of a nucleophilic addition reaction is shown below.
Carbon monoxide (CO) as a ligand can undergo nucleophilic attack when bound to a metal center of poor π−basicity, as the carbon center of the CO ligand is electron deficient owing to the ligand to metal σ−donation not being fully compensated by the metal to ligand π−back donation. Thus, activated CO ligand undergoes nucleophilic attack by the lithium reagent to give an anionic acyl ligand, which upon alkylation generates the famous Fischer carbene complex.
Nucleophilic abstraction
An example of a nucleophilic abstraction reaction is shown below.
Electrophilic addition
Similar to the nucleophilic addition and abstraction reactions, the electrophilic counterparts of these reactions also exist. An electrophilic attack is favored if the L n M fragment is a good π−base and a poor σ−acid i.e., when the complex is anionic with the metal center at low−oxidation state and/or when the other metal bound ligands are electron donating such that the ligand getting activated becomes electron rich from the π−back donation of the metal center and thus can undergo an external attack by an electrophile E + like H + and CH 3 I. The attack of the electrophiles may result in the formation of a bond between the electrophile and the activated unsaturated substrate, in which case it is called electrophilic addition, or may result in an abstraction of a part or the whole of the activated ligand, in which case it is called the electrophilic abstraction.
Electrophilic abstraction
An example of an electrophilic abstraction reaction is shown below.
Alkyl abstractions are often achieved by Hg 2 + that can proceed in two ways, ( i ) by an attack at the α−carbon of a metal alkyl bond leading to an inversion of configuration at the alkyl carbon and ( ii ) by an attack at the metal center leading to retention of configuration at the alkyl carbon. The inversion of configuration proceeds by the following pathway.
The retention of configuration proceeds by the following pathway.


SECTION 7.3 PROBLEM SET: SYSTEMS OF LINEAR EQUATIONS - SPECIAL CASES
Solve the following inconsistent or dependent systems by using the Gauss-Jordan method.
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\begin{aligned}
2 x+6 y&=8 \\
x+3 y&=4
\end{aligned}
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The sum of digits of a two digit number is 9. The sum of the number and the number obtained by interchanging the digits is 99. Find the number.
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\begin{aligned}
2 x-y &=10 \\
-4 x+2 y &=15
\end{aligned}
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\begin{aligned}
x+y+z&=6 \\
3 x+2 y+z&=14 \\
4 x+3 y+2 z&=20
\end{aligned}
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-
\begin{aligned}
x+2 y-4 z&=1 \\
2 x-3 y+8 z&=9
\end{aligned}
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Jessica has a collection of 15 coins consisting of nickels, dimes and quarters. If the total worth of the coins is $1.80, how many are there of each? Find all three solutions.
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SECTION 7.3 PROBLEM SET: SYSTEMS OF LINEAR EQUATIONS - SPECIAL CASES
Solve the following inconsistent or dependent systems by using the Gauss-Jordan method.
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A company is analyzing sales reports for three products: products X, Y, Z. One report shows that a combined total of 20,000 of items X, Y, and Z were sold. Another report shows that the sum of the number of item Z sold and twice the number of item X sold equals 10,000. Also item X has 5,000 more items sold than item Y. Are these reports consistent?
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\begin{aligned}
x+y+2 z=0 \\
x+2 y+z=0 \\
2 x+3 y+3 z=0
\end{aligned}
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-
Find three solutions to the following system of equations.
\begin{aligned}
x+2 y+z &=12 \\
y &=3
\end{aligned}
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\begin{aligned}
x+2 y&=5 \\
2 x+4 y&=k
\end{aligned}
For what values of k does this system of equations have
-
No solution?
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Infinitely many solutions?
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\(x + 3y - z = 5\)
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-
Why is it not possible for a linear system to have exactly two solutions? Explain geometrically.
|


23.5D: Electron Transport Chain
The electron transport chain uses the electrons from electron carriers to create a chemical gradient that can be used to power oxidative phosphorylation.
- Describe how electrons move through the electron transport chain
Key Points
- Oxidative phosphorylation is the metabolic pathway in which electrons are transferred from electron donors to electron acceptors in redox reactions; this series of reactions releases energy which is used to form ATP.
- There are four protein complexes (labeled complex I-IV) in the electron transport chain, which are involved in moving electrons from NADH and FADH 2 to molecular oxygen.
- Complex I establishes the hydrogen ion gradient by pumping four hydrogen ions across the membrane from the matrix into the intermembrane space.
- Complex II receives FADH 2 , which bypasses complex I, and delivers electrons directly to the electron transport chain.
- Ubiquinone (Q) accepts the electrons from both complex I and complex II and delivers them to complex III.
- Complex III pumps protons through the membrane and passes its electrons to cytochrome c for transport to the fourth complex of proteins and enzymes.
- Complex IV reduces oxygen; the reduced oxygen then picks up two hydrogen ions from the surrounding medium to make water.
Key Terms
- prosthetic group : The non-protein component of a conjugated protein.
- complex : A structure consisting of a central atom, molecule, or protein weakly connected to surrounding atoms, molecules, or proteins.
- ubiquinone : A lipid soluble substance that is a component of the electron transport chain and accepts electrons from complexes I and II.
Oxidative phosphorylation is a highly efficient method of producing large amounts of ATP, the basic unit of energy for metabolic processes. During this process electrons are exchanged between molecules, which creates a chemical gradient that allows for the production of ATP. The most vital part of this process is the electron transport chain, which produces more ATP than any other part of cellular respiration.
Electron Transport Chain
The electron transport chain is the final component of aerobic respiration and is the only part of glucose metabolism that uses atmospheric oxygen. Electron transport is a series of redox reactions that resemble a relay race. Electrons are passed rapidly from one component to the next to the endpoint of the chain, where the electrons reduce molecular oxygen, producing water. This requirement for oxygen in the final stages of the chain can be seen in the overall equation for cellular respiration, which requires both glucose and oxygen.
A complex is a structure consisting of a central atom, molecule, or protein weakly connected to surrounding atoms, molecules, or proteins. The electron transport chain is an aggregation of four of these complexes (labeled I through IV), together with associated mobile electron carriers. The electron transport chain is present in multiple copies in the inner mitochondrial membrane of eukaryotes and the plasma membrane of prokaryotes.
The electron transport chain : The electron transport chain is a series of electron transporters embedded in the inner mitochondrial membrane that shuttles electrons from NADH and FADH 2 to molecular oxygen. In the process, protons are pumped from the mitochondrial matrix to the intermembrane space, and oxygen is reduced to form water.
Complex I
To start, two electrons are carried to the first complex aboard NADH. Complex I is composed of flavin mononucleotide (FMN) and an enzyme containing iron-sulfur (Fe-S). FMN, which is derived from vitamin B 2 (also called riboflavin), is one of several prosthetic groups or co-factors in the electron transport chain. A prosthetic group is a non-protein molecule required for the activity of a protein. Prosthetic groups can be organic or inorganic and are non-peptide molecules bound to a protein that facilitate its function.
Prosthetic groups include co-enzymes, which are the prosthetic groups of enzymes. The enzyme in complex I is NADH dehydrogenase, a very large protein containing 45 amino acid chains. Complex I can pump four hydrogen ions across the membrane from the matrix into the intermembrane space; it is in this way that the hydrogen ion gradient is established and maintained between the two compartments separated by the inner mitochondrial membrane.
Q and Complex II
Complex II directly receives FADH 2 , which does not pass through complex I. The compound connecting the first and second complexes to the third is ubiquinone (Q). The Q molecule is lipid soluble and freely moves through the hydrophobic core of the membrane. Once it is reduced to QH 2 , ubiquinone delivers its electrons to the next complex in the electron transport chain. Q receives the electrons derived from NADH from complex I and the electrons derived from FADH 2 from complex II, including succinate dehydrogenase. This enzyme and FADH 2 form a small complex that delivers electrons directly to the electron transport chain, bypassing the first complex. Since these electrons bypass, and thus do not energize, the proton pump in the first complex, fewer ATP molecules are made from the FADH 2 electrons. The number of ATP molecules ultimately obtained is directly proportional to the number of protons pumped across the inner mitochondrial membrane.
Complex III
The third complex is composed of cytochrome b, another Fe-S protein, Rieske center (2Fe-2S center), and cytochrome c proteins; this complex is also called cytochrome oxidoreductase. Cytochrome proteins have a prosthetic heme group. The heme molecule is similar to the heme in hemoglobin, but it carries electrons, not oxygen. As a result, the iron ion at its core is reduced and oxidized as it passes the electrons, fluctuating between different oxidation states: Fe 2+ (reduced) and Fe 3+ (oxidized). The heme molecules in the cytochromes have slightly different characteristics due to the effects of the different proteins binding them, which makes each complex. Complex III pumps protons through the membrane and passes its electrons to cytochrome c for transport to the fourth complex of proteins and enzymes. Cytochrome c is the acceptor of electrons from Q; however, whereas Q carries pairs of electrons, cytochrome c can accept only one at a time.
Complex IV
The fourth complex is composed of cytochrome proteins c, a, and a 3 . This complex contains two heme groups (one in each of the cytochromes a and a 3 ) and three copper ions (a pair of Cu A and one Cu B in cytochrome a 3 ). The cytochromes hold an oxygen molecule very tightly between the iron and copper ions until the oxygen is completely reduced. The reduced oxygen then picks up two hydrogen ions from the surrounding medium to produce water (H 2 O). The removal of the hydrogen ions from the system also contributes to the ion gradient used in the process of chemiosmosis.


10.3: Conductivity of Some Common Materials
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The values below are conductivity \(\sigma\) for a few materials that are commonly encountered in electrical engineering applications, and for which conductivity emerges as a consideration.
Note that materials in some applications are described instead in terms of resistivity , which is simply the reciprocal of conductivity.
Conductivity may vary significantly as a function of frequency. The values below are representative of frequencies from a few kHz to a few GHz. Conductivity also varies as a function of temperature. In applications where precise values are required, primary references accounting for frequency and temperature should be consulted. The values presented here are gathered from a variety of references, including those indicated in “Additional References” at the end of this section.
Free Space (vacuum): \(\sigma\triangleq 0\).
| Material | \(\sigma\) (S/m) |
|---|---|
| Copper | \(5.8\times 10^7\) |
| Gold | \(4.4\times 10^7\) |
| Aluminum | \(3.7\times 10^7\) |
| Iron | \(1.0\times 10^7\) |
| Platinum | \(0.9\times 10^7\) |
| Carbon | \(1.3\times 10^5\) |
| Silicon | \(4.4\times 10^{-4}\) |
Water exhibits \(\sigma\) ranging from about \(6~\mu\)S/m for highly distilled water (thus, a very poor conductor) to about \(5\) S/m for seawater (thus, a relatively good conductor), varying also with temperature and pressure. Tap water is typically in the range 5–50 mS/m, depending on the level of impurities present.
Soil typically exhibits \(\sigma\) in the range \(10^{-4}\) S/m for dry soil to about \(10^{-1}\) S/m for wet soil, varying also due to chemical composition.
Non-conductors . Most other materials that are not well-described as conductors or semiconductors and are dry exhibit \(\sigma < 10^{-12}\) S/m. Most materials that are considered to be insulators , including air and common dielectrics, exhibit \(\sigma < 10^{-15}\) S/m, often by several orders of magnitude.


11.2: Preparing for the NCLEX
The National Council Licensure Examination for Registered Nurses ( NCLEX-RN ) is the exam that nursing graduates must pass successfully to obtain their nursing license and become a registered nurse. The purpose of the NCLEX is to evaluate if a nursing graduate (i.e., candidate) is competent to provide safe, competent, entry-level nursing care. The NCLEX-RN is developed by the National Council of State Board of Nursing (NCSBN), an independent, nonprofit organization composed of the 50 state boards of nursing and other regulatory agencies. [1]
The NCLEX-RN is a pass/fail examination administered on a computer using computer adaptive testing (CAT). CAT means that every time a candidate answers a test item, the computer reestimates their ability based on all their previous answers and the difficulty of those items. The computer then selects the next item based on an estimated 50% chance of the candidate answering it correctly. In this manner, the next item is not too easy nor too difficult, and a candidate’s true ability level is determined. Each item is perceived by the candidate as challenging because it is targeted to their ability. With each item answered, the computer’s estimate of the candidate’s ability becomes more precise.
The computer stops providing items when it is 95% certain that the candidate’s ability is clearly above or clearly below the passing standard, the candidate has received the maximum number of questions, or the candidate has run out of time without demonstrating a competence level to pass. Testing accommodations may be provided for eligible candidates with the authorization of the candidate’s State Board of Nursing (SBON). [2] , [3]
See an image of a simulated graduate taking the NCLEX in Figure 11.1. [4]
Read more about the NCLEX at https://www.ncsbn.org/nclex.htm .
Watch a video about how the NCLEX uses computer assistive technology (CAT) at https://www.ncsbn.org/356.htm .
Registering to Take the NCLEX
Before you can register to take the NCLEX, you will need an Authorization to Test (ATT). To receive an ATT, complete the following steps [5] :
- Apply for a nurse license from your State Board of Nursing (SBON) or other nursing regulatory body
- Register with Pearson VUE and pay the exam fee
- Wait to receive your ATT from Pearson Vue
- Schedule your exam with Pearson VUE
Be sure to start this process well in advance of your target date for taking the NCLEX.
Read specific instructions regarding registering and taking the NCLEX-RN by downloading the most current NCLEX-Candidate Bulletin from the NCSBN. The content includes the following:
- Registering for the exam
- Scheduling the exam
- Understanding test site rules and regulations
- Preparing for the day of the exam
Download the most current NCLEX-Candidate Bulletin from https://www.ncsbn.org/nclex.htm .
Next Generation NCLEX
A new edition of NCLEX will be released in 2023 with “Next Generation” questions. (If you take the NCLEX before the new edition is released, you may be asked to voluntarily participate in a special research section that tests the accuracy of these new types of questions without your performance counting toward your final score.)
The Next Generation NCLEX (Next Gen) uses evolving case studies and new types of test questions based on a new NCSBN Clinical Judgment Measurement Model (NCJMM) that assesses how well the candidate can think critically and use clinical judgment when providing nursing care. The NCJMM assess the candidate’s ability to recognize cues, analyze cues, prioritize hypotheses, generate solutions, take actions, and evaluate outcomes. [6]
Five new Next Generation test item types are called extended multiple response, extended drag and drop, cloze (drop-down), extended hot spot (highlighting), and matrix-grid:
- Extended Multiple Response: Extended Multiple Response items allow candidates to select one or more answer options at a time. This item type is similar to the current NCLEX multiple response item but has more options and uses partial credit scoring. [7]
- Extended Drag and Drop: Extended Drag and Drop items allow candidates to move or place response options into answer spaces. This item type is like the current NCLEX ordered response items but not all of the response options may be required to answer the item. In some items, there may be more response options than answer spaces. [8]
- Cloze (Drop – Down): Cloze (Drop – Down) items allow candidates to select one option from a drop-down list. There can be more than one drop-down list in a cloze item. These drop-down lists can be used as words or phrases within a sentence or within tables and charts. [9]
- Enhanced Hot Spot (Highlighting): Enhanced Hot Spot items allow candidates to select their answer by highlighting predefined words or phrases. Candidates can select and deselect the highlighted parts by clicking on the words or phrases. These types of items allow an individual to read a portion of a client medical record (e.g., a nursing note, medical history, lab values, medication record, etc.), and then select the words or phrases that answer the item. [10]
- Matrix/Grid: Matrix/Grid items allow the candidate to select one or more answer options for each row and/or column. This item type can be useful in measuring multiple aspects of the clinical scenario with a single item. In the example below, each of the eight rows will need to have one of the three answer choices selected. [11]
View a NCSBN video on Next Generation test items.
Participate in an NCLEX tutorial at https://www.ncsbn.org/nclex-tutorial.htm .
Preparing for the Examination
Since the first day of nursing school, you have been working towards successfully passing the NCLEX-RN. After you graduate, it is important to implement strategies for success for taking the NCLEX, such as reviewing the NCLEX-RN Test Plan, setting up a dedicated review schedule based on your test date, and reviewing material you learned throughout nursing school. [12]
NCLEX Test Plan
The NCLEX-RN Test Plan provides a concise summary of the content and scope of the exam and serves as an excellent guide for preparation. NCLEX-RN test plans are updated every three years based on surveys of newly licensed registered nurses to ensure the NCLEX questions reflect fair, comprehensive, current, and entry-level nursing competency. [13]
The NCLEX Test Plan categorizes test questions based on categories and subcategories referred to as “Client Needs” [14] :
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Safe and Effective Care Environment
- Management of Care
- Safety and Infection Control
- Health Promotion and Maintenance
- Psychosocial Integrity
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Physiological Integrity
- Basic Care and Comfort
- Pharmacological and Parenteral Therapies
- Reduction of Risk Potential
- Physiological Adaptation
In addition, the following concepts are applied throughout the client needs categories [15] :
- Nursing Process
- Caring
- Communication and Documentation
- Teaching and Learning
- Culture and Spirituality
Download the current NCLEX-RN Test Plan from https://www.ncsbn.org/testplans.htm .
Review Schedule
Many students find it helpful to create and follow a study calendar with topics to review based on the NCLEX Test Plan.
Day of the Examination
On the day of the examination, it is normal to experience some anxiety. However, it is important to use techniques to manage anxiety so it does not impact your ability to think through and answer the test questions. Use positive self-talk and remind yourself that you have been preparing for this examination since the first day of nursing school. Read additional tips for the day of the NCLEX and tips for testing in the following boxes.
| Tips for the Day of the NCLEX [18] |
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| Tips for Testing [19] |
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After the Examination
If your State Board of Nursing (SBON) or nursing regulatory body (NRB) participates in the “ Quick Results Service ,” you can receive your “unofficial” results two business days after the exam if you pay for this service. Official results are sent to you approximately six weeks after the exam. [20]
If you didn’t pass the exam, you’ll receive an NCLEX Candidate Performance Report (CPR). The CPR is an individualized document that shows how a candidate performed in each of the test plan content areas. Graduates who fail the exam can use the CPR as a guide to prepare them to retake the exam. [21]
If you need to retake the exam, you will need to wait a minimum of 45 days before you can retake the NCLEX per NCSBN policy. This length of time is determined by your SBON (or NRB) and will be reflected in your new ATT’s validity dates. Read the steps for retaking the NCLEX in the following box.
| Steps for Retaking the NCLEX |
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- NCSBN. https://www.ncsbn.org/nclex.htm ↵
- NCSBN. https://www.ncsbn.org/nclex.htm ↵
- NCSBN Examinations. (2021). 2021 NCLEX examination candidate bulletin . https://www.ncsbn.org/candidatebulletin.htm ↵
- “ Woman_with_computer.jpg ” by Cumminsr at English Wikipedia is licensed under CC BY-SA 3.0 ↵
- NCSBN. https://www.ncsbn.org/nclex.htm ↵
- NCSBN. https://www.ncsbn.org/nclex.htm ↵
- NCSBN. https://www.ncsbn.org/nclex.htm ↵
- NCSBN. https://www.ncsbn.org/nclex.htm ↵
- NCSBN. https://www.ncsbn.org/nclex.htm ↵
- NCSBN. https://www.ncsbn.org/nclex.htm ↵
- NCSBN. https://www.ncsbn.org/nclex.htm ↵
- NCSBN. https://www.ncsbn.org/nclex.htm ↵
- NCSBN. https://www.ncsbn.org/nclex.htm ↵
- NCSBN. https://www.ncsbn.org/nclex.htm ↵
- NCSBN. https://www.ncsbn.org/nclex.htm ↵
- NCSBN. https://www.ncsbn.org/nclex.htm ↵
- NCSBN Examinations. (2021). 2021 NCLEX examination candidate bulletin . https://www.ncsbn.org/candidatebulletin.htm ↵
- NCSBN. https://www.ncsbn.org/nclex.htm ↵
- NCSBN. https://www.ncsbn.org/nclex.htm ↵
- NCSBN. https://www.ncsbn.org/nclex.htm ↵
- NCSBN. https://www.ncsbn.org/nclex.htm ↵


14.7.1: Community Health Centers
Community Health Centers or local clinics provide comprehensive medical services to underserved populations - including those who lack health insurance or housing, those with low incomes, seniors (over age 65), and immigrants or refugees. Patients may be charged for medical services, but on a sliding scale - which means that fees are set based on what patients are able to pay (HRSA, 2024). These health centers receive funding in multiple ways: through block grants from the Health Resources & Services Administration (HRSA), the Centers for Disease Control and Prevention (CDC), Title X Service Grants (for sexual and reproductive health services), and reimbursement from Medicare, Medicaid, and CHIP or the VA. In order to become a Federally Qualified Health Center (FQHC), the clinic must:
- Be located in or serve a high need community.
- Be governed by a community board that is at least 51% made up of health center patients.
- Provide comprehensive healthcare services on a sliding fee scale based on ability to pay.
- Become a Health Center Program award recipient or Health Center Program look-alike. (CA Department of Health Care Services, n.d.)
- These clinics provide a broad range of services including:
- Primary care
- Dental and vision care
- Physical and occupational therapy
- Mental health services
- Substance abuse and addiction treatment
- STI/HIV testing and treatment
- Reproductive, maternal and pediatric healthcare
- Vaccines
- Health education
In order to receive Title X funding for reproductive healthcare, clinics must provide a variety of family planning methods, including contraception and infertility assistance. They must provide testing and treatment for sexually transmitted infections (STIs) including HIV. They may not provide abortion services, or even discuss abortion as an option (OASH, 2022). If the clinic does provide abortion services, there are recent (2019) requirements for clearly designating physical separation of those services in a different part of the clinic which receives a different source of funding. These requirements for separation caused many clinics to withdraw from title X funding (Seabert et al., 2021).


20.1: Thinking Critically about Your Semester
By the end of this section, you will be able to:
- Reflect on and write about the development of composing processes and how those processes affect your work.
- Demonstrate honesty and objectivity in reflecting on written work.
You have written your way through a long semester, and the journey is nearly complete. Now is the time to step back and reflect on what you have written, what you have mastered, what skill gaps remain, and what you will do to continue growing and improving as a communicator. This reflection will be based on the work you have done and what you have learned during the semester. Because the subject of this reflection is you and your work, no further research is required. The information you need is in the work you have done in this course and in your head. Now, you will work to organize and transfer this information to an organized written text. Every assignment you have completed provides you with insight into your writing process as you think about the assignment’s purpose, its execution, and your learning along the way. The skill of reflection requires you to be critical and honest about your habits, feelings, skills, and writing. In the end, you will discover that you have made progress as a writer, perhaps in ways not yet obvious.


18.7: Notes
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- Last updated
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- Herman Gray
- University of California Press
1 Miranda Banks, “How to Study Media and Makers,” in The Sage Handbook of Television Studies , ed. Manuel Alvarado, Milly Buonanno, Herman Gray, and Toby Miller (London: Sage, 2014).
2 John Caldwell, Production Culture: Industrial Reflexivity and Critical Practice in Film and Television (Durham, NC: Duke University Press, 2008).
3 “The News Media and the Disorders,” in Channeling Blackness: Studies on Television and Race in America , ed. Darnell Hunt (London: Oxford, 2005); Kerner Commission, Report of the National Advisory Commission on Civil Disorders (Washington, DC: U.S. Government Printing Office, 1968); Arthur S. Fleming, Stephen Horn, Frankie M. Freeman, Manuel Ruiz Jr., Murray Saltzman, and John A. Biggs, Window Dressing on the Set: Women and Minorities in Television (Washington, DC: U.S. Commission on Civil Rights, 1977).
4 See, for instance, Aniko Bodroghkozy, Equal Time: Television and the Civil Rights Movement (Urbana: University of Illinois Press, 2012); Lynn Spigel, Welcome to the Dreamhouse: Popular Media and Postwar Suburbs (Durham, NC: Duke University Press, 2001); Laurie Ouellette, Viewers Like You? How Public TV Failed the People (New York: Columbia University Press, 2002); Sasha Torres, Black, White, and in Color: Television and Black Civil Rights (Princeton, NJ: Princeton University Press, 2003); Chon Noriega, Shot in America: Television, the State, and the Rise of Chicano Cinema (Minneapolis: University of Minnesota Press, 2000); Devorah Heitner, Black Power TV (Durham, NC: Duke University Press, 2013); Steven Classen, Watching Jim Crow: The Struggle over Mississippi TV , 1955–1969 (Durham, NC: Duke University Press, 2004); Anna McCarthy, The Citizen Machine (New York: New Press, 2010); and Vicki Mayer, Below the Line: Producers and Production Studies in the New Television Economy (Durham, NC: Duke University Press, 2011).
5 Mayer, Below the Line , 13 (my emphasis); see also Kerner Commission, Report of the National Advisory Commission on Civil Disorders .
6 Mo Ryan, “Who Creates Drama at HBO? Very Few Women or People of Color,” Huffington Post , March 7, 2014.
7 Darnell Hunt, “Hollywood Story: Diversity, Writing and the End of Television as We Know It,” in The Sage Handbook of Television Studies , ed. Alvarado et al; Ralph Bunche Center, 2014 Hollywood Diversity Report: Making Sense of the Disconnect (Los Angeles: UCLA, 2014).
8 Hunt, “Hollywood Story,” 166.
9 Stacy Smith et al., “Gender Inequalities in 500 Popular Films: Examining On Screen Portrayals and Behind-the-Scenes Employment Patters in Motion Pictures Released between 2007–2012,” Annenberg Report (Los Angeles: University of Southern California, 2013); Stacy Smith et al., “Race/Ethnicity in 500 Popular Films: Is the Key to Diversifying Cinematic Content held in the Hand of the Black Director?” Media Diversity and Social Change Initiative (Los Angeles: University of Southern California, 2013).
10 Directors Guild of America, “‘A Fair Shot’: Women Directors on Television,” www.dga/Craft/DGAQ/All-Articles/1301-Winter (accessed September 19, 2014); Directors Guild of America, “DGA Report: Employers Make No Improvement in Diversity Hiring in Episodic Television,” www.dga.org/ News/PressReleases/2014/140917.
11 Pierre Bourdieu, The Field of Cultural Production: Essays on Art and Literature (New York: Columbia University Press, 1993).
12 Michael Curtin, “Media Capitals: Toward the Study of Spatial Flows,” International Journal of Cultural Studies 6.2 (2003): 202–228; Toby Miller, Nitin Govil, John McMurria, and Richard Maxwell, Global Hollywood (London: British Film Institute, 2001); David Hesmondhalgh, The Cultural Industries (Los Angeles: Sage, 2006).
13 George Yudice, The Expediency of Culture: The Uses of Culture in the Global Era (Durham, NC: Duke University Press, 2003); Arlene Davila, Culture Works: Space, Value, and Mobility across the Neoliberal Americas (New York: New York University Press, 2012).
14 Amanda Lotz, The Television Will be Revolutionized (New York: New York University Press, 2007).
15 Roderick Ferguson, The Reorder of Things: The University and Its Pedagogies of Minority Difference (Minneopolis: University of Minnesota Press, 2012).
16 Herman Gray, “Subject(ed) to Recognition,” American Quarterly 65.4 (2013): 771–799.
17 David Hesmondhalgh and Anamik Saha, “Race, Ethnicity and Cultural Production,” Popular Communication 11.3 (2013): 179–195.
18 Caldwell, Production Culture .
19 Laurie Ouellette and James Hay, Better Living through Reality TV (London: Wiley, 2008).
20 Felicia Henderson, “Options and Exclusivity: Economic Pressures on TV Writers’ Compensation and the Effects on TV Writer’s Room Culture,” in The Sage Handbook of Television Studies , ed. Alvarado et al.
21 Caldwell, Production Culture .
22 Mayer, Below the Line ; Sarah Banet-Weiser, Authentic (New York: New York University Press, 2012).
23 Timothy Havens, Black Television Travels: African American Media around the Globe (New York: New York University Press, 2013); Hunt, “Hollywood Story.”
24 Jennifer Peterson, Murder, the Media, and the Politics of Public Feelings (Bloomington: Indiana University Press, 2011).


8: Contemporary Issues for Children and Families
Issues for Children and Families
Socialization intends to instill developmental skills in children for them to successfully function in their larger target communities. Children are members of several groups and structure within their nested systems. The developmental skills or tasks of a specific society differ from group to group depending on the cultural group the child belongs to. Factors that impact a child’s socialization are ethnicity, gender, sexual orientation, ability or class; skill development is thus dependent on the individual and the societal demand within the Bronfenbrenner's larger macrosystem influence.
Even at a young age, children are impacted by experiences that occur in the larger society. In response to these experiences children’s beliefs, values attitudes will be shaped. How do society issues impact the way children are socialized? How do these societal changes redefine children’s needs and development?
Some of key contemporary experiences and exposures include issues of related discrimination and prejudice and bias in all forms, and larger Bronfenbrenner’s chronosystem changes such as the COVID-19 pandemic has on the socializing agent of media.