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Effects of Cholesterol in Stress-Related Neuronal Death—A Statistical Analysis Perspective
Get PDFThe association between plasma cholesterol levels and the development of dementia continues to be an important topic of discussion in the scientific community, while the results in the literature vary significantly. We study the effect of reducing oxidized neuronal cholesterol on the lipid raft structure of plasma membrane. The levels of plasma membrane cholesterol were reduced by treating the intact cells with methyl-ß-cyclodextrin (MßCD). The relationship between the cell viability with varying levels of MßCD was then examined. The viability curves are well described by a modified form of the empirical Gompertz law of mortality. A detailed statistical analysis is performed on the fitting results, showing that increasing MßCD concentration has a minor, rather than significant, effect on the cellular viability. In particular, the dependence of viability on MßCD concentration was found to be characterized by a ~25% increase per 1 μM of MßCD concentration
From the Horse\u27s Mouth: Voices of the Nonhuman in Classic Children\u27s Literature
Get PDFChildren’s literature often features anthropomorphized talking animal characters with individual lives and voices. This thesis clarifies the types of animal voices heard in children’s literature, utilizing a tripartite spectrum of expressions of animal emotions and perspectives, moralizing speech, and world building or plot progressing speech. This framework facilitates the exploration of the animal-human relationships and events of communication which shine through human-filtered animal voices. Using this framework, this thesis analyzes Anna Sewell’s Black Beauty, Hugh Lofting’s The Story of Doctor Dolittle and The Voyage of Doctor Dolittle, and C. S. Lewis’s The Magician’s Nephew, The Lion, the Witch and the Wardrobe, and The Horse and His Boy. In these works of classic children’s literature, animal voices advocate for animal rights, affirm animal subjectivity, explore the imagined lives of animals, and explore the methods and benefits of communication between human and nonhuman animals
Relationship Dissolution and Self-Concept Change
No full textThe formation and functioning of close relationships can alter individuals’ self-concepts in such a manner that the self-concepts are cognitively linked with the partner; however, relationship dissolution directly threatens the loss of this intertwined self-concept. In this chapter, we first discuss the degree to which prior relationship-induced self-concept change predicts, and in some cases inoculates against, dissolution. Second, we discuss the extent to which relationship dissolution leads to subsequent self-concept changes within individuals (e.g., loss of self-concept content, increased self-concept confusion), as well as the mechanisms underlying whether these post-dissolution self-concept changes are deemed harmful versus beneficial. Third, we explain how individuals may recover from post-dissolution self-concept changes by seeking to repair or restore the damaged self-concept. Finally, we briefly identify avenues for future research that scholars may consider pursuing
Trace Elements Cycling in a Crude Oil-Contaminated Aquifer near Bemidji, Northern Minnesota
Get PDFReduction of ferric (Fe(III)) hydroxides is an important electron accepting process within a crude oil-contaminated aquifer near Bemidji, MN, USA. Fe(III) hydroxides commonly sorb trace elements in aquifer sediments; when they are reductively dissolved, trace elements can be mobilized into groundwater. We present new analyses of spatial distribution in groundwater and in sediment that document the mobilization of barium (Ba), strontium (Sr), cobalt (Co), and nickel (Ni) from sediment into groundwater. In the most reducing zone of the aquifer, Ba, Sr, Co, and Ni concentrations are elevated in groundwater and depleted in sediments. Downgradient from this zone, supersaturation of groundwater with respect to Fe2+ and HCO3- leads to the precipitation of siderite, which sorbs Ba, Co, and Ni due to negative surface charge generated at the pH conditions in the Bemidji aquifer. At the transition zone between Fe(III) reducing conditions and (sub)oxic groundwater, hydrous ferric oxides precipitate, promoting sorption of Ba, Co, Ni, and Sr.
Results from mass balance modeling show that ≥99.5% of mass for each trace element is associated with sediment, both before and 40 years after the oil spill. However, mobilization into groundwater is associated with a 2x increase in Sr mass, 3x increase in Ba mass, 14x increase in Ni mass, and 33x increase in Co mass relative to the mass contained in uncontaminated groundwater. This dissolved mass was sufficient to exceed health advisory concentrations for Ba and Ni in drinking water. Our results highlight the importance of monitoring inorganic contaminants, and particularly trace elements, at organic contaminant sites
Life in a Harsh Environment: The Effects of Age, Sex, Reproductive Condition, and Season on Hair Cortisol Concentration in a Wild Non-Human Primate
Get PDFHair cortisol concentration (HCC) provides a long-term retrospective measure of hypothalamic–pituitary–adrenal axis activity, and is increasingly used to assess the life history, health and ecology of wild mammals. Given that sex, age, season and pregnancy influence HCC, and that it may indicate ongoing stress, we examined HCC in common marmosets (Callithrix jacchus) naturally inhabiting a hot and dry semi-desert like habitat, Caatinga, in northeastern Brazil. We trapped, measured, weighed, marked and collected shaved hair from the back of the neck of 61 wild marmosets during the wet and dry seasons. Using enzyme immunoassay, we found that HCC was higher in the dry season compared with the wet season among all age/sex classes. Females had significantly higher HCC than males, juveniles had higher HCC than adults, and reproductively active adult females and non-pregnant/non lactating adult females did not differ in HCC. There were no interaction effects of sex, age, group, or season on HCC. The magnitude of the effect of this extremely hot and dry environment (average yearly rainfall was only 271 mm) on HCC in common marmosets is difficult to ascertain as these animals are also experiencing a variety of other stressors. However, the elevated HCC seen in common marmosets during the 5–8 month dry season, suggests these primates face an extended period of heat, water and possibly nutritional stress, which appears to result in a high rate of juvenile mortality
The Context, Strategy and Performance of the American Safety Net Primary Care Providers: A Systematic Review
No full textPurpose: The objective of this research is to synthesize evidence on the relationship between context, strategies and performance in the context of federally qualified health centers (FQHCs), a core safety net health services provider in the United States. The research also identifies prior approaches to measure contextual factors, FQHC strategy and performance. Gaps in the research are identified, and directions for future research are provided.
Design/methodology/approach: A systematic review of peer-reviewed journal articles published between the years 1997 and 2017 was conducted using a bibliographic search of PubMed, Business Source Premier and ABI/Inform databases.
Findings: 28 studies were selected for the analysis. Results supported associations among contextual factors (organizational and environmental) and FQHC strategy and FQHC performance. The research also indicates that previous research was primarily emphasized on clinical performance with less focus on other types of FQHC performance. In addition, there exists a wide variability in terms of measuring context, FQHC strategy and performance.
Originality/value: Operating in resource-scarce and highly constraining environments, FQHCs have demonstrated the ability to stay innovative and competent as serving often unhealthier and costlier patient populations. To date, there has been no study that reviewed the relationships between context, FQHC strategy and FQHC performance. In addition, there is an absence of consensus on how context, FQHC strategy and FQHC performance are measured. This study is the first that examined context-strategy-performance relationships in the context of FQHCs
Baseline and Stress-Induced Corticosterone Levels Across Birds and Reptiles Do Not Reflect Urbanication Levels
Get PDFRates of human-induced environmental change continue increasing with human population size, potentially altering animal physiology and negatively affecting wildlife. Researchers often use glucocorticoid concentrations (hormones that can be associated with stressors) to gauge the impact of anthropogenic factors (e.g. urbanization, noise and light pollution). Yet, no general relationships between human-induced environmental change and glucocorticoids have emerged. Given the number of recent studies reporting baseline and stress-induced corticosterone (the primary glucocorticoid in birds and reptiles) concentrations worldwide, it is now possible to conduct large-scale comparative analyses to test for general associations between disturbance and baseline and stress-induced corticosterone across species. Additionally, we can control for factors that may influence context, such as life history stage, environmental conditions and urban adaptability of a species. Here, we take a phylogenetically informed approach and use data from HormoneBase to test if baseline and stress-induced corticosterone are valid indicators of exposure to human footprint index, human population density, anthropogenic noise and artificial light at night in birds and reptiles. Our results show a negative relationship between anthropogenic noise and baseline corticosterone for birds characterized as urban avoiders. While our results potentially indicate that urban avoiders are more sensitive to noise than other species, overall our study suggests that the relationship between human-induced environmental change and corticosterone varies across species and contexts; we found no general relationship between human impacts and baseline and stress-induced corticosterone in birds, nor baseline corticosterone in reptiles. Therefore, it should not be assumed that high or low levels of exposure to human-induced environmental change are associated with high or low corticosterone levels, respectively, or that closely related species, or even individuals, will respond similarly. Moving forward, measuring alternative physiological traits alongside reproductive success, health and survival may provide context to better understand the potential negative effects of human-induced environmental change
Late Cambrian Microbial Build-Ups, Llano Area, Central Texas: A Three-Phase Morphological Evolution
No full textAlthough Late Cambrian microbial build-ups were recognized in the Point Peak Member of the Wilberns Formation in Central Texas (USA) nearly 70 years ago, only a few studies focused specifically on the build-ups themselves. This study focuses on the interpretation of the regional (15 measured sections described in literature representing an area of 8000 km2) and local (field and drone photogrammetry studies in a 25 km2 area from within south Mason County) microbial build-up occurrence, describes their growth phases and details their interactions with the surrounding inter-build-up sediments. The study establishes the occurrence of microbial build-ups in the lower and upper Point Peak members (the Point Peak Member is informally broken up into the lower Point Peak and the upper Point Peak members separated by Plectotrophia zone). The lower Point Peak Member consists of three \u3c1 m thick microbial bioherms and biostrome units, in addition to heterolithic and skeletal/ooid grainstone and packstone beds. One, up to 14 m thick, microbial unit associated with inter-build-up skeletal and ooid grainstone and packstone beds, intercalated with mixed siliciclastic–carbonate silt beds, characterizes the upper Point Peak member. The microbial unit in the upper Point Peak member displays a three-phase growth evolution, from an initial colonization phase on flat based, rip-up clast lenses, to a second aggradation and lateral expansion phase, into a third well-defined capping phase. The ultimate demise of the microbial build-ups is interpreted to have been triggered by an increase of water turbidity caused by a sudden influx of fine siliciclastics. The lower Point Peak member represents inner ramp shallow subtidal and intertidal facies and the upper Point Peak member corresponds to mid-outer ramp subtidal facies. Understanding the morphological architecture and depositional context of these features is of importance for identifying signatures of early life on Earth