8.17H: Basidiomycota - The Club Fungi
- Describe the ecology and reproduction of the Basidiomycota
Basidiomycota: The Club Fungi
The fungi in the Phylum Basidiomycota are easily recognizable under a light microscope by their club-shaped fruiting bodies called basidia (singular, basidium), which are the swollen terminal cell of a hypha. The basidia, which are the reproductive organs of these fungi, are often contained within the familiar mushroom, commonly seen in fields after rain, on the supermarket shelves, and growing on your lawn. These mushroom-producing basidiomyces are sometimes referred to as “gill fungi” because of the presence of gill-like structures on the underside of the cap. The “gills” are actually compacted hyphae on which the basidia are borne. This group also includes shelf fungus, which cling to the bark of trees like small shelves. In addition, the basidiomycota includes smuts and rusts, which are important plant pathogens, and toadstools. Most edible fungi belong to the Phylum Basidiomycota; however, some basidiomycetes produce deadly toxins. For example, Cryptococcus neoformans causes severe respiratory illness.
The lifecycle of basidiomycetes includes alternation of generations. Spores are generally produced through sexual reproduction, rather than asexual reproduction. The club-shaped basidium carries spores called basidiospores. In the basidium, nuclei of two different mating strains fuse (karyogamy), giving rise to a diploid zygote that then undergoes meiosis. The haploid nuclei migrate into basidiospores, which germinate and generate monokaryotic hyphae. The mycelium that results is called a primary mycelium. Mycelia of different mating strains can combine and produce a secondary mycelium that contains haploid nuclei of two different mating strains. This is the dikaryotic stage of the basidiomyces lifecyle and it is the dominant stage. Eventually, the secondary mycelium generates a basidiocarp, which is a fruiting body that protrudes from the ground; this is what we think of as a mushroom. The basidiocarp bears the developing basidia on the gills under its cap.
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Key Points
- The majority of edible fungi belong to the Phylum Basidiomycota.
- The basidiomycota includes shelf fungus, toadstools, and smuts and rusts.
- Unlike most fungi, basidiomycota reproduce sexually as opposed to asexually.
- Two different mating strains are required for the fusion of genetic material in the basidium which is followed by meiosis producing haploid basidiospores.
- Mycelia of different mating strains combine to produce a secondary mycelium that contains haploid basidiospores in what is called the dikaryotic stage, where the fungi remains until a basidiocarp (mushroom) is generated with the developing basidia on the gills under its cap.
Key Terms
- basidiocarp : a fruiting body that protrudes from the ground, known as a mushroom, which has a developing basidia on the gills under its cap
- basidiomycete : a fungus of the phylum Basidiomycota, which produces sexual spores on a basidium
- Basidiomycota : a taxonomic division within the kingdom Fungi: 30,000 species of fungi that produce spores from a basidium
- basidium : a small structure, shaped like a club, found in the Basidiomycota phylum of fungi, that bears four spores at the tips of small projections
- basidiospore : a sexually-reproductive spore produced by fungi of the phylum Basidiomycota


Section 1.4: Green Space Programs as a Shared Growth and Communal Process- A Somali Gardener’s Journey in Minnesota
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- August John Hoffman
- Rebus Community
This case study narrative describes the personal growth process, learning experiences, and development of a young Somali-American woman (Amian) through the lens of a community gardening and green space program located in St. Paul, MN.
The Big Picture
Amian 1 is currently completing a graduate program in Individualized Studies with an emphasis in Gardening Development at Metropolitan State University and actively participates in developing healthy foods at several gardens in the Twin Cities region. Her focus is providing members of underrepresented groups with greater access to food plots and enabling them with resources in growing healthier foods. Community growth, collaboration, and communal development of healthy foods is the central thesis of this paper, and how one young woman’s efforts to provide access to healthier foods to underserved and marginalized community members gradually became realized through her work at the Inver Hills – Metropolitan State Community Garden during the Summer 2020 growing season. Amian’s long-term goals include promoting food justice to marginalized groups residing in the upper Midwest region and developing a more sustainable ecosystem that promotes autonomy and healthy living conditions. This case study identifies important psychosocial factors such as community engagement, collaboration, inclusion, and superordinate goals as vital concepts in not only helping to produce a successful community garden but perhaps more importantly how these intersectional qualities can help us to better understand one another and coexist within a more harmonious society.
Community gardening, natural outdoor and green space activities have recently gained empirical support in providing a broad range of health-related benefits, including reduced obesity (Ornelas, et al., 2018), ecological resilience among indigenous populations (Shava, et al., 2010), social capital (Alaimo, et al., 2010) and increased community resilience among immigrant populations (Okvat & Zautra, 2011). While community gardens, green space, and natural environments have long remained popular activities among individuals and family members living in both rural and urban environments, only recently have these environments been examined as providing specific benefits such as psychological well-being (Soga, et al., 2017) and improved quality of life among younger populations such as adolescents and children (McCracken, et al., 2016).
More recently, current research has identified activity and participation within community gardening and green space environments as particularly beneficial to immigrant and refugee populations (Hartwig & Mason, 2016). Community gardening and environmentally sustainable green space activities support fundamental principles shared by community psychologists in that they provide unique opportunities for diverse groups of individuals to work collaboratively and establish a stronger sense of community inclusion, engage in social change, and promote psychosocial health (Fetterman, 2015).
The Inver Hills – Metropolitan State University Community Garden
The Inver Hills – Metropolitan State University Community Garden was established in 2010 for the purpose of providing healthy foods to low-income families of the Dayton’s Bluff area located in St. Paul, MN. The garden was established primarily as a cooperative between two higher educational institutions of the Minnesota State System (Metropolitan State University and Inver Hills Community College) and provides an environmentally sustainable learning environment for students from both institutions to work collaboratively in producing a broad
range of healthy foods for community residents. The community garden (approximately one-half acre) is located on the southeast portion of the Inver Hills campus which is located in Inver Grove Heights, MN. The garden is comprised of three separate components or divisions: A cooperative garden area where students work in producing healthy foods for local food banks; a fruit tree orchard (over 60 fruit trees) consisting of over 16 different apple tree cultivars (i.e., Honeycrisp, FrostBite, Haralson, etc.); and the final segment consists of 40 vegetable garden plots (10’ X 10’) designated for community residents. Since 2010, the Inver Hills – Metropolitan State University Community Garden has produced over 15, 000 lbs. of a variety of fresh vegetables and over 3,000 lbs. of apples which have been donated to local charities and food distribution centers throughout St. Paul and Minneapolis. The purpose of this current case study is to provide a personal and in-depth description of how a young Somali-American woman (Amian) has participated and worked in several community gardens in the upper Midwest region (i.e., Big River Farms located in Marine on St. Croix, MN, The Interfaith Garden located in Minneapolis, MN, and The Inver Hills – Metropolitan State Community Garden).
The current case study will focus primarily on Amian’s work in developing her own community garden at the Inver Hills – Metropolitan State Community Garden located in Inver Grove Heights, MN. An interesting component of this case study review is in understanding how one individual uses her personal experiences in witnessing malnutrition and food insecurity as a young child in Somalia as both a transformational and motivational process in growing healthy foods for underserved populations in the Twin Cities region. Amian’s primary initiative in green space development and community gardening activities has been her early childhood experiences while growing up in Somalia, where food shortages and other natural resources (i.e., potable water) remain increasingly in short supply. Amian comments: “My goal [at the garden] is to grow food for the community specifically for the elders as well as teach healthy food options … and encourage health and wellness during these difficult times.” Additionally, we hope to provide useful information to other immigrant families who would like to participate in community stewardship programs such as community gardening and forestry programs to improve access to healthier foods.
Community Gardening, Social Integration and Health Promotion among Immigrant Families
Given the rapid increases in the populations of individuals living in impacted and urban environments, the benefits of both green space and community gardens are becoming both necessary and important activities that help in sustaining optimal physical and psychological health. For specific refugee and immigrant populations, often just having access to potable water and minimal amounts of sustainable foods are challenges that are faced on a daily basis. According to recent estimates published by the Food and Agricultural Organization (an international agency devoted to promoting healthy foods to impoverished families throughout the world), over 153 million people or approximately 26% of the population of sub-Saharan Africa will suffer from starvation or food insecurity (Food and Agriculture Organization of the United Nations, 2016). The need to promote community gardening programs and skills in producing healthy foods that are similar to the refugee’s native homeland and food environment is critical to the successful transition to the United States (Gichunge & Kidwaro, 2014). In Amian’s personal experience as a child growing up in Somalia, she experienced firsthand how food shortages can have serious negative consequences on the health and welfare of community residents, and how immigrants and POCI populations here in the United States often face disproportionate levels of food insecurity. More specifically, as the frequency of refugee and immigrant populations arriving in the United States have increased over time researchers have discovered that access to native foods through horticultural (i.e., community gardening) and green space programs play a critical link in successful adaptation, assimilation, and improved mental health (Hartwig & Mason, 2016; Wilson, et al., 2010).
Communities that educate how native foods are grown and provide tools and resources within those environments that facilitate a successful harvest can help immigrant families adapt to their new communities more successfully and also improve both psychosocial and physiological
measures of optimal health, including a greater “sense of identity with their former selves” (Hartwig & Mason, 2016, p. 1158). Measures of improved physical and psychosocial health included greater access to organic foods (Carney, et al., 2012), reduced cardiovascular disease, depression (Tracey, et al., 2020) and body mass index (BMI) (Soga, et al., 2017). Recent data suggests that community gardening programs have been associated with the development of healthier and more sustainable lifestyles (i.e., connection with nature, social health, and increased physical activity) that are compatible with ethnically diverse families who are currently living in urban environments (Tharrey, et al., 2019). Additionally, recent topics of research within the discipline of community psychology have identified green sustainable programs such as community gardening as a viable approach in promoting wellness and mental health especially among vulnerable populations (Androff, et al., 2017).
Communities that provide residents with opportunities to share knowledge and their own personal experiences in the development of a community garden not only improve food security but have also been identified as providing other numerous benefits to the community, such as increased social capital, resilience and empowerment among those residents who live within those neighborhoods (Alaimo, et al., 2010). Indeed, communities providing residents with an opportunity to participate in green space and community gardens are perceived as desirable
living environments that contribute to a greater sense of psychological well-being, social cohesiveness and trust (Spano, et al., 2020). Amian immigrated to the United States when she was eight years old and has had a life-long passion to provide healthy foods to the community members where she currently resides in Minneapolis, MN. Growing up in a drought-stricken community in Somalia, food and potable water have never been taken for granted and are considered precious commodities. Amian has seen families struggle in just maintaining enough food to survive and has commented that she would like to see a more “collective effort from the community” in participating and contributing to the development of increased sustainable gardening programs. The culture from which Amian is accustomed to is just that – collectivistically oriented to groups working together in promoting a better way of life for survival. In the United States, Amian has commented that people are more dispersed, competitive, and more concerned about getting ahead at the expense of others rather than working collectively to share benefits with each other. “I came from a communal environment” Amian explains, and “when families experience a crisis, such as a death in the family, the first thing we do is to bring food. Food has a wonderful way of bringing people together especially during times of stress and grief.”
Growing Food for a Healthy Community as an Educational Process
An important component of growing healthy foods for the community is education. Part of Amian’s goal in developing a healthy foods program is in helping children understand not only the benefits of healthier eating, but also the actual origins of the foods they consume. Amian is convinced that when children play a role in the development and maintenance of a community garden they are improving their knowledge about food but also are more likely to consume the foods that they have helped propagate. This is especially important with vegetables (i.e., leafy greens) that are healthy but are often less preferential and palatable for younger children (i.e., broccoli, spinach, and kale). In more collectivistically-oriented environments, groups of individuals (of all ages) work together and share the benefits of common goals that are vital to the survival and well-being of community members. Perhaps more importantly, younger populations of children who share in the responsibility of growing healthy and sustainable foods such as mulching, cultivating, planting seeds, and harvesting learn the delicate balance of sustainable eco-systems and the human responsibility in respecting the fragile and finite resources of the environment. Amian has indicated that she is “committed to serving the refugee and immigrant community in Minnesota because . . . I have seen first-hand from my own experiences [in Somalia] coming from an immigrant family. I know that I cannot do this alone, and that is why I have partnered with Big River Farms and The Interfaith Garden.”
From Somalia to Minnesota: Foods that Facilitate Resettlement & Assimilation
Community gardening programs, green space, and natural environments are unique in that they provide numerous health benefits to community residents in both urban and rural areas. Adapting to a new environment as an immigrant or refugee can be very stressful, and providing
native foods from one’s homeland can be an effective stress-coping mechanism that holds numerous benefits to individual health among vulnerable populations (Tracey, et al., 2020). Minnesota is rapidly becoming a common settlement worldwide among refugees and immigrants who are escaping a number of threats to their personal safety and well-being, including malnutrition, oppressive governments (i.e., ethnic genocide), and persecution for religious beliefs. Currently, Minnesota ranks as the 13th leading state within the United States in resettlement for refugees primarily from Sub-Sahara Africa and Southeast Asia (Hartwig & Mason, 2016, p. 1154).
A Greener Vision for the Future
An important scope and general purpose in community gardening and green space programs is the future itself and how to get more community members involved in participating in sustainable and healthy foods production. Several of the student participants in the community gardening program indicated that they enjoyed working with other students and community participants in providing healthier foods for low-income families. One of the student participants (Abdiaziz) commented that he “loved every minute of working outside to help produce healthy foods for the community members. Providing people with these kinds of opportunities gives us an opportunity to get to know each other better and help people who are less fortunate than us.” Amian has indicated that she is trying to help community members work with immigrant families in a more collaborative process that will not only teaching participants the nutritious benefits of her native foods from Somalia, but that most food-related problems (i.e., shortages of healthy foods) is actually preventable and human-related. “When I started growing my vegetables in the gardens
I noticed how much food is wasted here in the United States and that hunger is actually a ‘man-made’ phenomenon.” If she is provided with the resources and opportunities, Amian plans to build an even larger sustainable foods program in southeast Minnesota (Kenyon) up to 20 acres. Amian has indicated that some of her most formidable challenges have been in finding community stakeholders who are willing to help provide resources in the continued development of sustainable green space activities and community gardening programs.
Providing opportunities for immigrants to work in a more collaborative process in the development and proliferation of ethnic foods is an empowering process that can help people from all backgrounds to better understand different cultures. Community psychologists can help facilitate the process of bridging cultural gaps and reducing racial stereotypes by serving as advocates in the development of sustainable green space environments such as community gardens. Amian has found the process of developing sustainable community gardens and providing healthier foods from her native homeland of Somalia personally a very rewarding and intrinsically satisfying experience. Her long-term goals are to provide healthier and organic foods for vulnerable Somali populations and older adults who are currently facing economic hardships. Amian has recognized that “the
voices within the community need to be heard and . . . I would like to see more families eating healthier foods together and growing their own foods.” Amian’s proposal includes planting native seeds from her native homeland Somalia including leafy green vegetables, beans and even fried bananas for families with low incomes in the United States, including immigrant families from Somalia, Ethiopia, Kenya and Southeast Asia. Amian is also concerned about increasing global environmental pollution (i.e., the proliferation of plastics) which directly impacts the quality of soil and water used for agricultural purposes. Her future plans include working in environmentally sustainable projects in the St. Paul and Minneapolis areas and promoting greater access to healthier foods among Somali and other underrepresented populations in these areas. Additionally, Amian is trying to reduce the impact of global pollution through the education and practice of simple environmentally-responsible behaviors, such as recycling, composting, and developing rainwater irrigation systems for garden sites.
Conclusion
The benefits of community gardening cannot be understated. Results of evaluations and studies offer clear evidence that community gardens provide numerous health benefits, improved access to food, related nutritional needs, and improved mental health. An important aspect that can be overlooked is its promotion of social health and community cohesion, both essential aspects of a healthy community.
Read more at: https://nccommunitygardens.ces.ncsu.edu/resources-3/nccommunitygardens-research/
From Theory to Practice Reflections and Questions
- Community gardening and environmentally sustainable green space activities support fundamental principles shared by community psychologists in that they provide unique opportunities for diverse groups of individuals to work collaboratively and establish a stronger sense of community inclusion, engage in social change, and promote psychosocial health (Fetterman, 2015). Share with your classmates or others at least one other way, outside of formal education, that can foster a sense of community, engagement in social change, and the promotion of psychosocial health?
- This case story mentions that a challenge in doing social justice work involving food has been in finding community stakeholders who are willing to help provide resources in the continued development of sustainable green space activities and community gardening programs. Consider and provide examples of how you might address this challenge.
- In addition to physiological well-being, what are some psychological influences of food on one’s sense of community?
Note:
1 The person centered in this chapter summary, Amian (name changed), is aware that this chapter is being published and has provided her consent. Due to cultural restrictions of her native country (Somalia) she has requested to remain anonymous.
References
Alaimo, K., Reischl, T. M., & Allen, J. O. (2010). Community gardening, neighborhood meetings, and social capital. Journal of Community Psychology, 38 (4), 497-514.
Androff, D., Fike, C., & Rorke, J. (2017). Greening social work education: Teaching environmental rights and sustainability in community practice. Journal of Social Work Education, 53 (3), 399–413.
Carney, P. A., Hamada, J. L., Rdesinski, R., Sprager, L., Nichols, K. R., Liu, B. Y., Pelayo, J., Sanchez, A., & Shannon, J. (2012). Impact of a community gardening project on vegetable intake, food security, and family relationships: A community-based participatory research study. Journal of Community Health, 37 , 874-881.
Fetterman, D. M. (2015). Empowerment evaluation and community psychology: An alignment of values and principles designed to improve the human condition. In V. C. Scott & S. M. Wolfe (Eds.), Community psychology: Foundations for practice. (pp. 329–348). Sage Publications, Inc. https://doi.org/10.4135/9781483398150.n12
Food and Agriculture Organization of the United Nations (2016). Retrieved from:
Gichunge, C., & Kidwaro, F. (2014). Utamu wa Afrika (The sweet taste of Africa): The vegetable garden as part of resettled African refugees’ food environment. Nutrition & Dietetics , 71 , 270-275.
Hartwig, K. A., & Mason, M. (2016). Community gardens for refugees and immigrant communities as a means of health promotion. Journal of Community Health , 41 , 1153-1159.
Jason, L. A., Keys, C. B., Taylor, R. R., & Davis, M. I. (Eds.). (2004). Participatory community research: Theory and methods in action . Washington, DC: American Psychological Association.
McCracken, D. S., Allen, D. A., & Gow, A. J. (2016). Associations between urban green space and health-related quality of life in children. Preventive Medicine Reports , 3 , 211-221.
Okvat, H. A. & Zautra, A. J. (2011). Community gardening: A parsimonious path to individual, community, and environmental resilience. American Journal of Community Psychology, 47 , 374-387.
Ornelas, I. J., Osterbauer, K., Woo, L. Bishop, S. K., Deschenie, D, Beresford, S. A., & Lombard, K. (2018). Gardening for health: Patterns of gardening and fruit and vegetable consumption among the Navajo. Journal of Community Health , 43 , 1053-1060.
Shava, S., Krasny, M. E., Tidball, K. G., & Zazu, C. (2010). Agricultural knowledge in urban and resettled communities: Applications to social-ecological resilience and environmental education. Environmental Education Research, 16 (5-6), 575-589.
Soga, M., Cox, D.T.C., Yamaura, U., Gaston, K. J., Kurisu, K., & Hanaki, K. (2017). Health benefits of urban allotment gardening: Improved physical and psychological well-being and social integration. International Journal of Environmental Research and Public Health, 14 (1), 71. https://doi.org/10.3390/ijerph14010071
Spano, G. D’Este, M., Giannico, V., Carrus, G., Elia, M., Lafortezza, R., Panno, A., & Sanesi, G. (2020). Are community gardening and horticultural interventions beneficial for psychosocial well-being? A meta-analysis. International Journal of Environmental Research and Public Health, 17 (10), 3584. https://doi.org/10.3390/ijerph17103584
Tharrey, M., Perignon, M., Scheromm, P., Mejean, C., & Darmon, N. (2019). Does participating in community gardens promote sustainable lifestyles in urban settings? Design and protocol of the JArDinS study. BMC Public Health, 19(589). https://doi.org 10.1186/s12889-019-6815-0
Tracey, D., Gray, T., Sweeting, J., Kingsley, J., Bailey, A., & Pettitt, P. (2020). A systematic review protocol to identify the key benefits and associated program characteristics of community gardening for vulnerable populations. International Journal of Environmental Research and Public Health, 17 (6), 1-8.
Wilson, A., Renzaho, A.M.N. McCabe, M., & Swinburn, B. (2010). Towards understanding the new food environment for refugees from the Horn of Africa in Australiam, Health Place, 16 , 969-976,


2.3.0: Gramática
Conjugación
All Spanish verbs have a stem ( la raíz ) and an ending ( -ar / -er / -ir ).
| Verb | Stem | Ending |
|---|---|---|
| Pensar | pens | ar |
| Volver | volv | er |
| Pedir | ped | ir |
These verbs belong to a large group of verbs that change their stem in the present tense and fall into one of these three different types of changes in their stem:
- e → ie;
- o/u → ue;
- e → i
It is important to note that not all stem-changing verbs change for all subjects. To help you remember where the changes take place, we have a trick! Think of the verbs as being in the shape of a boot (see illustration below). The only forms that change are those inside the boot.
Which subjects require a stem change?
Let’s have a look at almorzar ( to eat lunch ) :
Notice that the verb conjugation endings are the same normal endings you learning in Spanish 107 for AR, ER, and IR verbs - the only difference now is that the verbs listed below require stem changes inside the boot.
Verbs with stems changes only occur in the following forms inside the boot:
- Yo
- Tú
- Él, ella, usted
- Ellos, ellas, ustedes
Verbos
Stem-changing Verbs: o/u → ue
| almorzar | to have lunch |
|---|---|
| acostarse | to go to bed |
| costar | to cost |
| dormir | to sleep |
| dormirse | to fall asleep |
| encontrar | to find |
| jugar* | to play a game or sport |
| mostrar | to show |
| poder | to be able to |
| probar | to taste/ to try on |
| volver | to come back/return |
*Jugar is the only u → ue stem change in this section. All the other verbs have a o → ue stem change inside the boot.
In Spanish, use the construction "Jugar + a + sport" to talk about playing a sport .
Remember that in Spanish, when "a" is followed by "el", we need the contraction "al".
- Me gusta jugar al (a + el) béisbol.
Based on the rules discussed, conjugate the verb poder . Write the forms next to the person. One has been done for you.
| yo puedo | nosotros |
|---|---|
| tú | vosotros |
| él/ella/usted | ellos/as /ustedes |
In Spanish, the verb poder is used in the same way as the modal can in English, to express you have the ability to do something, or, due to specific circumstances, you are able to do something. Like can , it is followed by a verb in the infinitive .
Have a look at these examples from Aimar’s email:
Modelo:
Estoy enferma y no puedo ir a la clase de química hoy. ¿Me puedes pasar tus notas?


28.0: Introduction
Dianah, a community health nurse employed by the district health department, is preparing for a home visit with her client, Serjay, who is on a ventilator and has a poor prognosis. Serjay has a large family consisting of his parents, three brothers, one sister, and extended family. The family must make end-of-life decisions. However, the family dynamics are strained. Some family members believe the client should be placed on comfort care, and others want more time. Dianah can see that each side loves Serjay and only wants the best for him, but she frequently ends up mediating family discussions. Nurses often work with complex client family dynamics, especially when clients are nearing the end of their lives.
Dianah’s work is typical of community health nursing. Nurses in this field must care for both the individual and the family. Families come in all shapes and sizes, with different risk factors, economic backgrounds, and resources. Nurses must apply a holistic perspective for health promotion, illness prevention, and illness management to individuals, families, and the population. With a focus on the family as client, this chapter describes the functions of the family, frameworks of practice nurses use when caring for the family, conducting a family assessment, and family violence.


19.5: Cancer Immunobiology and Immunotherapy
- Explain how the adaptive specific immune response responds to tumors
- Discuss the risks and benefits of tumor vaccines
Cancer involves a loss of the ability of cells to control their cell cycle, the stages each eukaryotic cell goes through as it grows and then divides. When this control is lost, the affected cells rapidly divide and often lose the ability to differentiate into the cell type appropriate for their location in the body. In addition, they lose contact inhibition and can start to grow on top of each other. This can result in formation of a tumor. It is important to make a distinction here: The term “cancer” is used to describe the diseases resulting from loss of cell-cycle regulation and subsequent cell proliferation. But the term “tumor” is more general. A “tumor” is an abnormal mass of cells, and a tumor can be benign (not cancerous) or malignant (cancerous).
Traditional cancer treatment uses radiation and/or chemotherapy to destroy cancer cells; however, these treatments can have unwanted side effects because they harm normal cells as well as cancer cells. Newer, promising therapies attempt to enlist the patient’s immune system to target cancer cells specifically. It is known that the immune system can recognize and destroy cancerous cells, and some researchers and immunologists also believe, based on the results of their experiments, that many cancers are eliminated by the body’s own defenses before they can become a health problem. This idea is not universally accepted by researchers, however, and needs further investigation for verification.
Cell-Mediated Response to Tumors
Cell-mediated immune responses can be directed against cancer cells, many of which do not have the normal complement of self-proteins, making them a target for elimination. Abnormal cancer cells may also present tumor antigens. These tumor antigens are not a part of the screening process used to eliminate lymphocytes during development; thus, even though they are self-antigens, they can stimulate and drive adaptive immune responses against abnormal cells.
Presentation of tumor antigens can stimulate naïve helper T cells to become activated by cytokines such as IL-12 and differentiate into T H 1 cells. T H 1 cells release cytokines that can activate natural killer (NK) cells and enhance the killing of activated cytotoxic T cells. Both NK cells and cytotoxic T cells can recognize and target cancer cells, and induce apoptosis through the action of perforins and granzymes. In addition, activated cytotoxic T cells can bind to cell-surface proteins on abnormal cells and induce apoptosis by a second killing mechanism called the CD95 (Fas) cytotoxic pathway.
Despite these mechanisms for removing cancerous cells from the body, cancer remains a common cause of death. Unfortunately, malignant tumors tend to actively suppress the immune response in various ways. In some cancers, the immune cells themselves are cancerous. In leukemia, lymphocytes that would normally facilitate the immune response become abnormal. In other cancers, the cancerous cells can become resistant to induction of apoptosis. This may occur through the expression of membrane proteins that shut off cytotoxic T cells or that induce regulatory T cells that can shut down immune responses.
The mechanisms by which cancer cells alter immune responses are still not yet fully understood, and this is a very active area of research. As scientists’ understanding of adaptive immunity improves, cancer therapies that harness the body’s immune defenses may someday be more successful in treating and eliminating cancer.
- How do cancer cells suppress the immune system?
- Describe how the immune system recognizes and destroys cancer cells.
Cancer Vaccines
There are two types of cancer vaccines: preventive and therapeutic. Preventive vaccines are used to prevent cancer from occurring, whereas therapeutic vaccines are used to treat patients with cancer. Most preventive cancer vaccines target viral infections that are known to lead to cancer. These include vaccines against human papillomavirus (HPV)and hepatitis B, which help prevent cervical and liver cancer, respectively.
Most therapeutic cancer vaccines are in the experimental stage. They exploit tumor-specific antigens to stimulate the immune system to selectively attack cancer cells. Specifically, they aim to enhance T H 1 function and interaction with cytotoxic T cells, which, in turn, results in more effective attack on abnormal tumor cells. In some cases, researchers have used genetic engineering to develop antitumor vaccines in an approach similar to that used for DNA vaccines (see Micro Connections: DNA vaccines ). The vaccine contains a recombinant plasmid with genes for tumor antigens; theoretically, the tumor gene would not induce new cancer because it is not functional, but it could trick the immune system into targeting the tumor gene product as a foreign invader.
The first FDA-approved therapeutic cancer vaccine was sipuleucel-T (Provenge), approved in 2010 to treat certain cases of prostate cancer. 1 This unconventional vaccine is custom designed using the patient’s own cells. APCs are removed from the patient and cultured with a tumor-specific molecule; the cells are then returned to the patient. This approach appears to enhance the patient’s immune response against the cancer cells. Another therapeutic cancer vaccine (talimogene laherparepvec, also called T-VEC or Imlygic) was approved by the FDA in 2015 for treatment of melanoma, a form of skin cancer. This vaccine contains a virus that is injected into tumors, where it infects and lyses the tumor cells. The virus also induces a response in lesions or tumors besides those into which the vaccine is injected, indicating that it is stimulating a more general (as opposed to local) antitumor immune response in the patient.
- Explain the difference between preventative and therapeutic cancer vaccines.
- Describe at least two different approaches to developing therapeutic anti-cancer vaccines.
Viruses typically destroy the cells they infect—a fact responsible for any number of human diseases. But the cell-killing powers of viruses may yet prove to be the cure for some types of cancer, which is generally treated by attempting to rid the body of cancerous cells. Several clinical trials are studying the effects of viruses targeted at cancer cells. Reolysin, a drug currently in testing phases, uses reoviruses (respiratory enteric orphan viruses) that can infect and kill cells that have an activated Ras-signaling pathway, a common mutation in cancerous cells. Viruses such as rubeola (the measles virus) can also be genetically engineered to aggressively attack tumor cells. These modified viruses not only bind more specifically to receptors overexpressed on cancer cells, they also carry genes driven by promoters that are only turned on within cancer cells. Herpesvirus and others have also been modified in this way.
Key Concepts and Summary
- Cancer results from a loss of control of the cell cycle, resulting in uncontrolled cell proliferation and a loss of the ability to differentiate.
- Adaptive and innate immune responses are engaged by tumor antigens, self-molecules only found on abnormal cells. These adaptive responses stimulate helper T cells to activate cytotoxic T cells and NK cells of innate immunity that will seek and destroy cancer cells.
- New anticancer therapies are in development that will exploit natural adaptive immunity anticancer responses. These include external stimulation of cytotoxic T cells and therapeutic vaccines that assist or enhance the immune response.
Footnotes
- 1 National Institutes of Health, National Cancer Institute. "Cancer Vaccines." www.cancer.gov/about-cancer/c...-fact-sheet#q8. Accessed on May 20, 2016.


15.5: Excel Chart in Word Document
Learning Objectives
- Create a Word document with integrated Excel chart.
There are a couple of ways to integrate an Excel chart into a Word document.
Option 1 for Chart Integration
The next piece of information needed in the report is the annual sales chart. To enter this data, Rosamine makes sure her cursor is at the place in the report she wants the chart to go. She clicks back to the Insert tab and selects the Chart button.
The next step is to select the type of chart to use for her report. In this instance, Rosamine chooses a line chart.
- Chart Button/Line Chart . Rosamine selects the chart button and then selects a Line chart to use in her report.
- Chart Options. There are seven different variations for displaying a Line chart. Rosamine selects the first option.
- OK Button. With the desired chart selected, Rosamine clicks the OK button and the chart is placed in her report.
Next, Rosamine selects the style of line chart to use and begins to enter information to create the chart itself.
The chart will contain the total sales numbers from the last three years for each of the three retail stores. She puts the years in Column A (purple color), the name of the stores across row 1 (pink color), and the sales figures in the rest of the cells (blue color). Here is what her chart now looks like in the report.
Rosamine clicks on the chart title box and changes the name of the chart to Annual Total Sales. Rosamine notices that the numbers are difficult to see, so she resizes the chart to make it easier to read.
Rosamine resizes the chart by clicking on the mid-points in the chart and dragging them to a larger size that still fits within the document column width.
The General Manager will now see the rise and fall of sales over the last three years in Rosamine’s report.
To finish the report, Rosamine types in the rest of the text. Next she needs to link a PowerPoint presentation file for a reference mentioned in the report.
Option 2 for Chart Integration
What if Rosamine already had access to the Annual Total Sales chart file? She could copy and paste the chart into her document. First she opens the Excel file with the chart in it. Since she has learned to copy and paste from the previous table, she puts the Word and Excel windows side-by-side on her screen, then takes the following steps:
- Select chart . Rosamine selects the chart in the Excel file by clicking once on the chart.
- Right-click mouse. Rosamine clicks the right mouse button. She sees a menu appear and selects the Copy choice. She can also use the Ctrl+C keys to copy the chart.
- Paste chart in Word document. With the desired chart copied, Rosamine moves over to her Word document and places the curser in the correct spot and right-clicks again to bring up the menu. In the menu she selects the Paste option and the chart is placed in the document. She can also use the Ctrl+V keys to paste the chart.
- Resize chart. Rosamine now grabs one of the chart border area spots and moves it to the desired size in the document.
- Change chart. If Rosamine needed to change something about the chart like the type of chart, the data in the chart, the labels, and so on, she can right-click on the chart itself, and a menu will appear that allows her to change aspects of that chart. Any changes made will not affect the original Excel file chart.
If Rosamine wanted to use the copy and paste keyboard shortcut it would be exactly like the copy and paste from the table example and look like this:
To finish the report, Rosamine types in the rest of the text. Next, she needs to link a PowerPoint presentation file for a reference mentioned in the report.
Contributors and Attributions
- Excel Chart in Word Document. Authored by : Sherri Pendleton. Provided by : Lumen Learning. License : CC BY: Attribution


1.4: Assignment- Primary Functions of Management
Preparation
Our text describes the four important and dynamic primary functions of management as planning, organizing, leading, and controlling. In this assignment you will identify, describe, and differentiate the four functions. The following steps will help you prepare for your written assignment:
- Carefully consider the four primary functions of management in the context of a business you know. This could be your workplace, Nokia or ThyssenKrupp introduced to you earlier, or another selected business you are familiar with.
- Select one of the four functions of management that your reading and consideration leads you to believe is the most important. If you believe no single function stands out, then you may select the interoperability of all four.
Your Task
Write a three-paragraph essay describing your chosen function, and why you rank its importance so highly. Your essay must include three properly referenced and defined terms from the module reading. For example, if you select Controlling, you could include the definition of feedback loop . Answer and address these questions:
- What is the primary function you selected?
- How does it interact with the other functions?
- What would happen to “management” without your selected function?
- What factors cause you to rank its importance above the others?
In addition to the text, you are encouraged to research your topic using reliable and properly cited Internet resources.
Contributors and Attributions
- Assignment: Primary Functions of Management. Authored by : Betty Fitte and Lumen Learning. License : CC BY: Attribution


9.S: Math Models and Geometry (Summary)
Key Terms
| angle | An angle is formed by two rays that share a common endpoint. Each ray is called a side of the angle. |
| area | The area is a measure of the surface covered by a figure. |
| complementary angles | If the sum of the measures of two angles is 90°, then they are called complementary angles. |
| cone | A cone is a solid figure with one circular base and a vertex. |
| cube | A cube is a rectangular solid whose length, width, and height are equal. |
| cylinder | A cylinder is a solid figure with two parallel circles of the same size at the top and bottom. |
| equilateral triangle | A triangle with all three sides of equal length is called an equilateral triangle. |
| hypotenuse | The side of the triangle opposite the 90° angle is called the hypotenuse. |
| irregular figure | A figure that is not a standard geometric shape. Its area cannot be calculated using any of the standard area formulas. |
| isosceles triangle | A triangle with two sides of equal length is called an isosceles triangle. |
| legs of a right triangle | The sides of a right triangle adjacent to the right angle |
| perimeter | The perimeter is a measure of the distance around a figure. |
| rectangle | A geometric figure that has four sides and four right angles. |
| right triangle | A triangle that has one 90° angle. |
| similar figures | In geometry, if two figures have exactly the same shape but different sizes, we say they are similar figures. |
| supplementary angles | If the sum of the measures of two angles is 180°, then they are called supplementary angles. |
| trapezoid | A four-sided figure, a quadrilateral, with two sides that are parallel and two sides that are not. |
| triangle | A geometric figure with three sides and three angles. |
| vertex of an angle | When two rays meet to form an angle, the common endpoint is called the vertex of the angle. |
Key Concepts
9.1 - Use a Problem Solving Strategy
-
Problem Solving Strategy
- Read the word problem. Make sure you understand all the words and ideas. You may need to read the problem two or more times. If there are words you don't understand, look them up in a dictionary or on the internet.
- Identify what you are looking for.
- Name what you are looking for. Choose a variable to represent that quantity.
- Translate into an equation. It may be helpful to first restate the problem in one sentence before translating.
- Solve the equation using good algebra techniques.
- Check the answer in the problem. Make sure it makes sense.
- Answer the question with a complete sentence.
9.2 - Solve Money Applications
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Finding the Total Value for Coins of the Same Type
- For coins of the same type, the total value can be found as follows:$$number \cdot value = total\; value$$where number is the number of coins, value is the value of each coin, and total value is the total value of all the coins.
-
Solve a Coin Word Problem
- Read the problem. Make sure you understand all the words and ideas, and create a table to organize the information.
- Identify what you are looking for.
-
Name
what you are looking for. Choose a variable to represent that quantity.
- Use variable expressions to represent the number of each type of coin and write them in the table.
- Multiply the number times the value to get the total value of each type of coin.
- Translate into an equation. Write the equation by adding the total values of all the types of coins.
- Solve the equation using good algebra techniques.
- Check the answer in the problem and make sure it makes sense.
- Answer the question with a complete sentence.
Table 9.16
| Type | Number | Value ($) | Total Value ($) |
|---|---|---|---|
9.3 - Use Properties of Angles, Triangles, and the Pythagorean Theorem
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Supplementary and Complementary Angles
- If the sum of the measures of two angles is 180°, then the angles are supplementary.
- If ∠A and ∠B are supplementary, then m∠A + m∠B = 180 .
- If the sum of the measures of two angles is 90°, then the angles are complementary.
- If ∠A and ∠B are complementary, then m∠A + m∠B = 90.
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Solve Geometry Applications
- Read the problem and make sure you understand all the words and ideas. Draw a figure and label it with the given information.
- Identify what you are looking for.
- Name what you are looking for and choose a variable to represent it.
- Translate into an equation by writing the appropriate formula or model for the situation. Substitute in the given information.
- Solve the equation using good algebra techniques.
- Check the answer in the problem and make sure it makes sense.
- Answer the question with a complete sentence.
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Sum of the Measures of the Angles of a Triangle
- For any ΔABC, the sum of the measures is 180°
- m∠A + m∠B = 180
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Right Triangle
- A right triangle is a triangle that has one 90° angle, which is often marked with a ⦜ symbol.
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Properties of Similar Triangles
- If two triangles are similar, then their corresponding angle measures are equal and their corresponding side lengths have the same ratio.
9.4 - Use Properties of Rectangles, Triangles, and Trapezoids
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Properties of Rectangles
- Rectangles have four sides and four right (90°) angles.
- The lengths of opposite sides are equal.
- The perimeter, P , of a rectangle is the sum of twice the length and twice the width.$$P = 2L + 2W$$
- The area, A, of a rectangle is the length times the width.$$A = L \cdot W$
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Triangle Properties
- For any triangle ΔABC , the sum of the measures of the angles is 180°.$$m \angle A + m \angle B + m \angle C = 180°$$
- The perimeter of a triangle is the sum of the lengths of the sides.$$P = a + b + c$$
- The area of a triangle is one-half the base, b, times the height, h.$$A = \dfrac{1}{2} bh$$
9.5 - Solve Geometry Applications: Circles and Irregular Figures
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Problem Solving Strategy for Geometry Applications
- Read the problem and make sure you understand all the words and ideas. Draw the figure and label it with the given information.
- Identify what you are looking for.
- Name what you are looking for. Choose a variable to represent that quantity.
- Translate into an equation by writing the appropriate formula or model for the situation. Substitute in the given information.
- Solve the equation using good algebra techniques.
- Check the answer in the problem and make sure it makes sense.
- Answer the question with a complete sentence.
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Properties of Circles
- d = 2r
- Circumference: C = 2\(\pi\)r or C = \(\pi\)d
- Area: A = \(\pi\)r 2
9.6 - Solve Geometry Applications: Volume and Surface Area
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Volume and Surface Area of a Rectangular Solid
- V = LWH
- S = 2LH + 2LW + 2WH
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Volume and Surface Area of a Cube
- V = s 3
- S = 6s 2
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Volume and Surface Area of a Sphere
- V = \(\dfrac{4}{3} \pi\)r 3
- S = 4\(\pi\)r 2
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Volume and Surface Area of a Cylinder
- V = \(\pi\)r 2 h
- S = 2\(\pi\)r 2 + 2\(\pi\)rh
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Volume of a Cone
- For a cone with radius r and height h: Volume: V = \(\dfrac{1}{3} \pi\)r 2 h
9.7 - Solve a Formula for a Specific Variable
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Distance, Rate, and Time
- d = rt
Contributors and Attributions
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Lynn Marecek (Santa Ana College) and MaryAnne Anthony-Smith (Formerly of Santa Ana College). This content is licensed under Creative Commons Attribution License v4.0 "Download for free at<EMAIL_ADDRESS>."


7.2: Power-Operated Hand Tools
Power-Operated Hand Tools
Electric power-operated tools must be either of the approved double-insulated type or grounded in accordance with OSHA 29 CFR 1926, Subpart K. "Approved" means accepted, certified, listed, labeled, or otherwise determined to be safe by a qualified testing laboratory. In addition, these requirements must be followed for use of power-operated hand tools:
- Do not permit the use of electric cords for hoisting or lowering tools.
- Remove all damaged portable electric tools from use and tag them "Do Not Use."
- Secure hose or whip pneumatic power tools by some positive means to prevent the tool from becoming accidentally disconnected.
- Securely install and maintain safety clips or retainers on pneumatic impact (percussion) tools to keep attachments from being accidentally expelled.
- Ensure that all pneumatically driven nailers, staplers, and other similar equipment that are provided with automatic fastener feeds (that operate at more than 100 psi pressure at the tool) have safety devices on the muzzle to prevent the tool from ejecting fasteners unless the muzzle is in contact with the work surface.
- Do not allow compressed air to be used for cleaning purposes except where reduced to less than 30 psi and then only with effective chip guarding and PPE that meets the requirements of 29 CFR 1926 Subpart E. The 30 psi requirement does not apply for concrete form, mill scale, and similar cleaning purposes.
- Do not exceed the manufacturer's safe operating pressure for hoses, pipes, valves, filters, and other fittings.
- Do not permit the use of hoses for hoisting or lowering tools.
- Ensure that all hoses exceeding ½-inch inside diameter have a safety device at the source of supply or branch line to reduce pressure in case of hose failure.
- Equip airless spray guns of the type that atomize paints and fluids at high pressures (1,000lbs or more per sq. in.) with automatic or visible manual safety devices to prevent pulling of the trigger and releasing paint or fluid until the safety
- device is manually released, or, provide a diffuser nut that will prevent high pressure, high velocity release while the nozzle tip is removed as well as a nozzle tip guard, or other equivalent protection, that will prevent the tip from corning into contact with the operator.
- Equip abrasive blast cleaning nozzles with an operating valve that must be held open manually. Provide a support on which the nozzle can be mounted when it is not in use.
- turn off all fuel-powered tools while refueling, servicing, or maintaining them. Transport, handle, and store fuel in accordance with 29 CFR 1926, Subpart F.
- Apply applicable requirements, as outlined in 29 CFR 1926, Subparts D and E, for concentrations of toxic gases and use of PPE when using fuel-powered tools in enclosed spaces.
Powder-actuated tools
These requirements must be followed for use of powder-actuated tools:
- Allow only workers who have been trained in the operation of the particular tool in use to operate a powder-operated tool.
- Test the tool daily before loading, in accordance with the manufacturer's recommendations, to ensure that safety devices are in proper working condition.
- Remove from service immediately any tool not in proper working order or that develops a defect during use, and do not use it again until it is repaired.
- Ensure that all PPE is in accordance with 29 CFR 1926, Subpart E.
- Do not load tools until just prior to the intended firing time. Never point either loaded or empty tools at any person. Keep hands clear of the open barrel end. Never leave loaded tools unattended.
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Do not drive fasteners into hard or brittle materials including, but not limited to, the following:
- cast iron
- glazed tile
- surface-hardened steel
- glass block
- live rock
- face brick
- hollow tile
- Avoid driving pins or fasteners into materials that are easily penetrated unless such materials are backed by a substance that will prevent the pin or fastener from passing completely through and creating a flying missile hazard on the other side. Never drive a fastener into a spalled area caused by an unsatisfactory fastening.
- Do not use tools in an explosive or flammable atmosphere. Always use tools with the correct shield, guard, or attachment recommended by the manufacturer.
Abrasive wheels and tools
These requirements must be followed for use of abrasive wheels and tools:
- Ensure that all grinding machines are supplied with sufficient power to maintain the spindle speed at safe levels under all conditions of normal operation.
- Ensure that all grinding machines are equipped with safety guards that cover the spindle end, nut, and flange projections, that the safety guard is mounted to maintain proper alignment with the wheel, and that the strength of the fastenings exceeds the strength of the guard.
- Provide safety guards (protection hoods) for floor-stand and bench-mounted abrasive wheels used for external grinding. Ensure that the maximum angular exposure of the grinding wheel periphery and sides is not more than 90 degrees, except that when work requires contact with the wheel below the horizontal plane of the spindle where the angular exposure must not exceed 125 degrees. In either case, ensure that the exposure does not begin more than 65 degrees above the horizontal plane of the spindle. The safety guards must be strong enough to withstand the effect of a bursting wheel, and work rests that are rigidly supported and readily adjustable must be provided for floor- and bench-mounted grinders. Work rests must be kept at a distance not more than 1/8 inch from the surface of the wheel.
- Inspect closely and ring-test all abrasive wheels before mounting to ensure that they are free from cracks and defects.
- Ensure that grinding wheels fit freely and are not forced on the spindle. Tighten the spindle nut only enough to hold the wheel in place. Protect all workers using abrasive wheels with eye protection equipment in accordance with the requirements of 29 CFR 1926, Subpart E, unless adequate eye protection is afforded by eye shields that are permanently attached to the bench or floor stand.
Jacks and Hydraulic Tools
These requirements must be followed for use of jacks and hydraulic tools:
- Mark the manufacturers rated capacity legibly on all jacks and ensure that the capacity is not exceeded.
- Make sure that all jacks have a positive stop to prevent over travel.
- Make sure that the base of the jack is blocked or cribbed when it needs a firm foundation. Place a wood block between the cap and the load if a possibility of slippage of the metal cap of the jack exists.
- Crib, block, or otherwise secure the load immediately after it has been raised.
- Supply hydraulic jacks exposed to freezing temperatures with adequate antifreeze liquid.
- Lubricate all jacks at regular intervals.
- Inspect each jack thoroughly at times depending upon the service conditions. Inspect no less frequently that the following intervals:
- For constant or intermittent use at one locality, once every six months
- For jacks sent out of shop for special work, when sent out and when returned
- For a jack subjected to abnormal load or shock, immediately before and immediately thereafter
- Tag jacks that are out of order and ensure that they are not used until rep


24.2C: Supply of Blood and Nerves to the Kidneys
The renal veins drain the kidney and the renal arteries supply blood to the kidney.
- Summarize the blood and nerve supply of the kidney
Key Points
- The renal arteries branch off of the abdominal aorta and supply the kidneys with blood. The arterial supply of the kidneys varies from person to person, and there may be one or more renal arteries to supply each kidney.
- The renal veins are the veins that drain the kidneys and connect them to the inferior vena cava.
- The kidney and the nervous system communicate via the renal plexus. The sympathetic nervous system will trigger vasoconstriction and reduce renal blood flow, while parasympathetic nervous stimulation will trigger vasodilation and increased blood flow.
- Afferent arterioles branch into the glomerular capillaries, while efferent arterioles take blood away from the glomerular capillaries and into the interlobular capillaries that provide oxygen to the kidney.
Key Terms
- renal artery : These arise off the side of the abdominal aorta, immediately below the superior mesenteric artery, and supply the kidneys with blood.
- renal vein : The veins that drain the kidney and connect the kidney to the inferior vena cava.
Because the kidney filters blood, its network of blood vessels is an important component of its structure and function. The arteries, veins, and nerves that supply the kidney enter and exit at the renal hilum.
Renal Arteries
The renal arteries branch off of the abdominal aorta and supply the kidneys with blood. The arterial supply of the kidneys is variable from person to person, and there may be one or more renal arteries supplying each kidney.
Due to the position of the aorta, the inferior vena cava, and the kidneys in the body, the right renal artery is normally longer than the left renal artery. The renal arteries carry a large portion of the total blood flow to the kidneys—up to a third of the total cardiac output can pass through the renal arteries to be filtered by the kidneys.
Renal blood supply starts with the branching of the aorta into the renal arteries (which are each named based on the region of the kidney they pass through) and ends with the exiting of the renal veins to join the inferior vena cava. The renal arteries split into several segmental arteries upon entering the kidneys, which then split into several arterioles.
These afferent arterioles branch into the glomerular capillaries, which facilitate fluid transfer to the nephrons inside the Bowman’s capsule, while efferent arterioles take blood away from the glomerulus, and into the interlobular capillaries, which provide tissue oxygenation to the parenchyma of the kidney.
Renal Veins
The renal veins are the veins that drain the kidneys and connect them to the inferior vena cava. The renal vein drains blood from venules that arise from the interlobular capillaries inside the parenchyma of the kidney.
Renal Plexus
The renal plexus are the source of nervous tissue innervation within the kidney, which surround and primarily alter the size of the arterioles within the renal cortex. Input from the sympathetic nervous system triggers vasoconstriction of the arterioles in the kidney, thereby reducing renal blood flow into the glomerulus.
The kidney also receives input from the parasympathetic nervous system, by way of the renal branches of the vagus nerve (cranial nerve X), which causes vasodilation and increased blood flow of the afferent arterioles. Due to this mechanism, sympathetic nervous stimulation will decrease urine production, while parasympathetic nervous stimulation will increase urine production.
Blood supply to the kidneys : The renal arteries branch off of the abdominal aorta and supply the kidneys with blood.


1: Measurements and Atomic Structure
Chemistry is the study of matter and the ways in which different forms of matter combine with each other.  Everything you touch or taste or smell is a chemical, and the interactions of these chemicals with each other define our universe. Chemistry forms the fundamental basis for biology and medicine. From the structure of proteins and nucleic acids, to the design, synthesis and manufacture of drugs, chemistry allows you an insight into how things work. Chapter One in this text will introduce you to matter, atoms and their structure. You will learn the basics of scientific measurement and you will gain an appreciation of the scale of chemistry; from the tiniest atom to the incredibly large numbers dealt with in the “mole concept” ( Chapter 4 ). Chapter One lays the foundation on which we will build our understanding.
Thumbnail: Two small test tubes held in spring clamps. (CC BY-SA 3.0 Unported; Amitchell125 via Wikipedia )


3.1.4: Scientific Method
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In the preceding sections, we described science as knowledge acquired through a scientific method. So what exactly is the “scientific method”? Scientific method refers to a standardized set of techniques for building scientific knowledge, such as how to make valid observations, how to interpret results, and how to generalize those results. The scientific method allows researchers to independently and impartially test preexisting theories and prior findings, and subject them to open debate, modifications, or enhancements. The scientific method must satisfy four key characteristics:
- Logical : Scientific inferences must be based on logical principles of reasoning.
- Confirmable : Inferences derived must match with observed evidence.
- Repeatable : Other scientists should be able to independently replicate or repeat a scientific study and obtain similar, if not identical, results.
- Scrutinizable : The procedures used and the inferences derived must withstand critical scrutiny (peer review) by other scientists.
Any branch of inquiry that does not allow the scientific method to test its basic laws or theories cannot be called “science.” For instance, theology (the study of religion) is not science because theological ideas (such as the presence of God) cannot be tested by independent observers using a logical, confirmable, repeatable, and scrutinizable. Similarly, arts, music, literature, humanities, and law are also not considered science, even though they are creative and worthwhile endeavors in their own right.
The scientific method, as applied to social sciences, includes a variety of research approaches, tools, and techniques, for collecting and analyzing qualitative or quantitative data. These methods include laboratory experiments, field surveys, case research, ethnographic research, action research, and so forth. Much of this book is devoted to learning about these different methods. However, recognize that the scientific method operates primarily at the empirical level of research, i.e., how to make observations and analyze these observations. Very little of this method is directly pertinent to the theoretical level, which is really the more challenging part of scientific research.


4.6: Conservation Laws
No General Conservation Laws
Some of the first tensors we discussed were mass and charge, both rank-0 tensors, and the rank-1 momentum tensor, which contains both the classical energy and the classical momentum. Physicists originally decided that mass, charge, energy, and momentum were interesting because these things were found to be conserved. This makes it natural to ask how conservation laws can be formulated in relativity. We’re used to stating conservation laws casually in terms of the amount of something in the whole universe, e.g., that classically the total amount of mass in the universe stays constant. Relativity does allow us to make physical models of the universe as a whole, so it seems as though we ought to be able to talk about conservation laws in relativity.
- We can’t.
First, how do we define “stays constant?” Simultaneity isn’t well-defined, so we can’t just take two snapshots, call them initial and final, and compare the total amount of, say, electric charge in each snapshot. This difficulty isn’t insurmountable. As in figure a, we can arbitrarily pick out three-dimensional spacelike surfaces — one initial and one final — and integrate the charge over each one. A law of conservation of charge would say that no matter what spacelike surface we picked, the total charge on each would be the same.
Next there’s the issue that the integral might diverge, especially if the universe was spatially infinite. For now, let’s assume a spatially finite universe. For simplicity, let’s assume that it has the topology of a three-sphere (see section 8.2 for reassurance that this isn’t physically unreasonable), and we can visualize it as a two-sphere.
In the case of the momentum four-vector, what coordinate system would we express it in? In general, we do not even expect to be able to define a smooth, well-behaved coordinate system that covers the entire universe, and even if we did, it would not make sense to add a vector expressed in that coordinate system at point A to another vector from point B; the best we could do would be to parallel-transport the vectors to one point and then add them, but parallel transport is path-dependent. (Similar issues occur with angular momentum.) For this reason, let’s restrict ourselves to the easier case of a scalar, such as electric charge.
But now we’re in real trouble. How would we go about actually measuring the total electric charge of the universe? The only way to do it is to measure electric fields, and then apply Gauss’s law. This requires us to single out some surface that we can integrate the flux over, as in Figure 4.5.2. This would really be a two-dimensional surface on the three-sphere, but we can visualize it as a one-dimensional surface — a closed curve — on the two-sphere. But now suppose this curve is a great circle, Figure 4.5.3. If we measure a nonvanishing total flux across it, how do we know where the charge is? It could be on either side.
The conclusion is that conservation laws only make sense in relativity under very special circumstances. 16 We do not have anything like over-arching, global principles of conservation. As an example of the appropriate special circumstances, section 6.2 shows how to define conserved quantities, which behave like energy and momentum, for the motion of a test particle in a particular metric that has a certain symmetry. This is generalized in section 7.1 to a general, global conservation law corresponding to every continuous symmetry of a spacetime.
Note
For another argument leading to the same conclusion, see section 7.5 .
Conservation of Angular Momentum and Frame Dragging
Another special case where conservation laws work is that if the spacetime we’re studying gets very flat at large distances from a small system we’re studying, then we can define a far-away boundary that surrounds the system, measure the flux through that boundary, and find the system’s charge. For such asymptotic flatness spacetimes, we can also get around the problems that crop up with conserved vectors, such as momentum. (Asymptotic flatness is discussed in more detail in section 7.4 .) If the spacetime far away is nearly flat, then parallel transport loses its path-dependence, so we can unambiguously define a notion of parallel-transporting all the contributions to the flux to one arbitrarily chosen point P and then adding them. Asymptotic flatness also allows us to define an approximate notion of a global Lorentz frame, so that the choice of P doesn’t matter.
As an example, Figure 4.5.4 shows a jet of matter being ejected from the galaxy M87 at ultrarelativistic fields. The blue color of the jet in the visible-light image comes from synchrotron radiation , which is the electromagnetic radiation emitted by relativistic charged particles accelerated by a magnetic field. The jet is believed to be coming from a supermassive black hole at the center of M87. The emission of the jet in a particular direction suggests that the black hole is not spherically symmetric. It seems to have a particular axis associated with it. How can this be? Our sun’s spherical symmetry is broken by the existence of externally observable features such as sunspots and the equatorial bulge, but the only information we can get about a black hole comes from its external gravitational (and possibly electromagnetic) fields.  What aspect of the initial conditions in the formation of the hole could have determined such an axis? The most likely candidate is the angular momentum. We are thus led to suspect that black holes can possess angular momentum, that angular momentum preserves information about their formation, and that angular momentum is externally detectable via its effect on the spacetime metric.
What would the form of such a metric be? Spherical coordinates in flat spacetime give a metric like this:
\[ds^{2} = dt^{2} - dr^{2} - r^{2} d \theta^{2} - r^{2} \sin^{2} \theta d \phi^{2} \ldotp\]
We’ll see in chapter 6 that for a non-rotating black hole, the metric is of the form
\[ds^{2} = (\ldots) dt^{2} - (\ldots) dr^{2} - r^{2} d \theta^{2} - r^{2} \sin^{2} \theta d \phi^{2},\]
where (. . .) represents functions of r. In fact, there is nothing special about the metric of a black hole, at least far away; the same external metric applies to any spherically symmetric, non-rotating body, such as the moon. Now what about the metric of a rotating body? We expect it to have the following properties:
- It has terms that are odd under time-reversal, corresponding to reversal of the body’s angular momentum.
- Similarly, it has terms that are odd under reversal of the differential d\(\phi\) of the azimuthal coordinate.
- The metric should have axial symmetry, i.e., it should be independent of \(\phi\).
Restricting our attention to the equatorial plane \(\theta = \frac{\pi}{2}\), the simplest modification that has these three properties is to add a term of the form
\[f(\ldots) L d \phi dt,\]
where (. . .) again gives the r-dependence and L is a constant, interpreted as the angular momentum. A detailed treatment is beyond the scope of this book, but solutions of this form to the relativistic field equations were found by New Zealand-born physicist Roy Kerr in 1963 at the University of Texas at Austin.
The astrophysical modeling of observations like figure d is complicated, but we can see in a simplified thought experiment that if we want to determine the angular momentum of a rotating body via its gravitational field, it will be difficult unless we use a measuring process that takes advantage of the asymptotic flatness of the space. For example, suppose we send two beams of light past the earth, in its equatorial plane, one on each side, and measure their deflections, e. The deflections will be different, because the sign of d\(\phi\) dt will be opposite for the two beams. But the entire notion of a “deflection” only makes sense if we have an asymptotically flat background, as indicated by the dashed tangent lines. Also, if spacetime were not asymptotically flat in this example, then there might be no unambiguous way to determine whether the asymmetry was due to the earth’s rotation, to some external factor, or to some kind of interaction between the earth and other bodies nearby.
It also turns out that a gyroscope in such a gravitational field precesses. This effect, called frame dragging, was predicted by Lense and Thirring in 1918, and was finally verified experimentally in 2008 by analysis of data from the Gravity Probe B experiment, to a precision of about 15%. The experiment was arranged so that the relatively strong geodetic effect (6.6 arc-seconds per year) and the much weaker Lense-Thirring effect (.041 arc-sec/yr) produced precessions in perpendicular directions. Again, the presence of an asymptotically flat background was involved, because the probe measured the orientations of its gyroscopes relative to the guide star IM Pegasi.