Natural selection reduced diversity on human Y chromosomes

The human Y chromosome exhibits surprisingly low levels of genetic diversity. This could result from neutral processes if the effective population size of males is reduced relative to females due to a higher variance in the number of offspring from males than from females. Alternatively, selection acting on new mutations, and affecting linked neutral sites, could reduce variability on the Y chromosome. Here, using genome-wide analyses of X, Y, autosomal and mitochondrial DNA, in combination with extensive population genetic simulations, we show that low observed Y chromosome variability is not consistent with a purely neutral model. Instead, we show that models of purifying selection are consistent with observed Y diversity. Further, the number of sites estimated to be under purifying selection greatly exceeds the number of Y-linked coding sites, suggesting the importance of the highly repetitive ampliconic regions. While we show that purifying selection removing deleterious mutations can explain the low diversity on the Y chromosome, we cannot exclude the possibility that positive selection acting on beneficial mutations could have also reduced diversity in linked neutral regions, and may have contributed to lowering human Y chromosome diversity. Because the functional significance of the ampliconic regions is poorly understood, our findings should motivate future research in this area.Comment: 43 pages, 11 figure

Title on page 1: Moral distress : values and barriers experience by critical care nurses

Includes vita.This dissertation explores the presence of moral distress and effective interventions to lessen its impact on critical care nurses. Manuscript one was completed prior to entering the doctor of philosophy in nursing program but was instrumental in building the foundation for successive work within this dissertation. An exploratory, descriptive designed study was used to examine moral distress and identify situations in which nurse's experienced high levels of moral distress. Nurses completed a 38-item moral distress scale, a coping questionnaire, and indicated their preferred methods for institutional support in managing distressing situations. Manuscript two includes a formal analysis of the Moral Distress Theory and identified limitations in the existing theoretical model based on a review of literature. Finally, manuscript three is a study identifying barriers and values during moral distress situations that can be used to potentially target interventions aimed at lessening the impact of moral distress.Dr. Gregory Alexander, Dissertation Supervisor.|Includes vita.Includes bibliographical references

Food Security in Alaska: Assisting the Alaska Food Policy Council to Meet Their Strategic Plan Goals Through the Use of GIS Mapping Technology

Presented to the Faculty of the University of Alaska Anchorage in Partial Fulfillment of the Requirements for the Degree of MASTER OF PUBLIC HEALTHThe Alaska Food Policy Council (AFPC) was established to examine how the Alaska food system functions, and to provide ideas and recommendations for improving access to healthy, affordable, culturally appropriate foods for all the state’s citizens. At the start of this project, AFPC did not have a resource tool that allows for the mapping of gaps, projects, initiatives, and strengths of the Alaska food system. Thus, this project focused on developing such a tool to assist AFPC with meeting their strategic plan goals, i.e., promoting the affordability, safety, accessibility and infrastructure of the Alaska food system. Secondary analysis of data relating to AFPC goals was conducted, and associated information was plotted using a GIS mapping tool. The creation of the map introduces a visual tool which can assist in providing an overall picture of the gaps and strengths identified in Alaska’s food system. This project can be used as a starting point for the future development of a real-time web-based GIS map that AFPC and other stakeholders can use to support recommendations to the state on food security related issues.Signature Page / Title Page / Abstract / Table of Contents / Table of Figures / Chapter 1 Introduction to Food Security / Chapter 2 Introduction to GIS / Chapter 3 Goals, Aims, and Objectives / Chapter 4 Activities and Methods / Chapter 5 Results and Discussion / Chapter 6 Strengths and Limitations / Chapter 7 Conclusions / Chapter 8 Recommendation

ANALYSIS OF GENES REQUIRED FOR QUIESCENT CELL FORMATION IN STATIONARY PHASE CULTURES OF SACCHAROMYCES CEREVISIAE

Yeast cells in stationary phase cultures, after several days growth in rich, glucose-based medium (YPD), are separable by density-gradient centrifugation into two fractions. The heavier, quiescent cells are mostly virgin daughters whereas the less-dense, non-quiescent cells, are a typical mixture of daughters to aged cells. Quiescent cells can also be separated based on expression of specific GFP-tagged proteins, including many that are localized to the mitochodria. To ask the question, what genes are required for this differentiation process, we used a combination of the diploid, homozygous yeast deletion set, the heterozygous deletion set (carrying one deleted \u27essential\u27 gene) and a third set designed to reduce mRNA abundance of a number of \u27essential\u27 genes. Samples from the cultures just prior to the diauxic shift (just prior to glucose exhaustion), stationary phase, and isolated quiescent (Q) and nonquiescent (NQ) cells were harvested and technical and biological replicates analyzed by microarray analysis. The results showed that deletions in more than 500 genes resulted in 2-fold or greater reduction in Q-cell formation. Thus, almost 10% of genes in the yeast genome were important for Q-cell formation. When mutants with a 2-fold in Q vs all other samples were compared, 411 genes were identified that were important for Q cells vs DS, NQ, and SP. These genes encoded proteins involved in mitochondrial function, protein localization, and vesicle transport. We concluded from these results that differentiation of quiescent cells requires a major cellular commitment and that the major functions required are similar to those identified by proteomic and transcriptomic analysis of Q cells done previously in our laboratory, furthering understanding of cell differentiation

ADULTHOOD DEFINITION AND PROFESSIONAL TRANSITION IN SMEs

The objective of this study is to analyze the opinions held by directors of SMEs (small and medium-sized companies), in relation to the concept of adulthood; and how this directly impacts career transition initiatives. Semi-structured interviews were carried out with 13 managers. Subsequently, a Likert scale was used to process the information proceeded by the Spearman's non-parametric correlation test. The results indicate that the definition that managers have of youth and adulthood, has a direct impact on their human resource planning

Asthma and depression: a pragmatic review of the literature and recommendations for future research

BACKGROUND: Although the association between asthma and psychosocial factors has long been recognised, it is only in the last decade that the impact of coexisting asthma and depression has become the focus of considerable research interest. However, the findings so far have been confusing and often contradictory. This paper sets out a methodical review and appraisal of the literature to date, including suggestions for future research. METHOD: PubMed and PsycINFO databases were used to search for English-language articles relating to asthma and depression research. The resulting articles were then reviewed and summarised, creating a report that was used to develop research recommendations. RESULTS: The main findings from this review included: (a) results are mixed as to whether persons with asthma are more likely to be depressed than those without asthma; (b) asthma and depression may have an 'additive' adverse effect on the normal asthma-related quality of life reductions; (c) subjective measures of asthma severity may be more strongly related to depression than objective measures; (d) specific asthma symptoms appear to be linked to depression; (e) sadness and depression can produce respiratory effects consistent with asthma exacerbations; (f) depression appears to be negatively related to asthma treatment compliance; (g) corticosteroid use in asthma treatment has been associated with depression, though it is unclear how common this problem is in real life; (h) interventions that address the physical, psychological, and social consequences of asthma are likely to lead to the most successful treatment outcomes; (i) treating the depression of individuals with asthma is likely to minimise the negative effects of the coexistence; and (j) a number of common methodological problems were observed in the literature. RECOMMENDATIONS: There is a large amount of research yet to be undertaken to clarify issues around asthma and depression, with the overdue next step being to design integrated treatment approaches, and carry out large-scale prospective studies to determine the impact of using such approaches to treat individuals with depression and asthma. Such studies will be the only way in which some fundamental questions about the development and coexistence of these two conditions will be answered

Seeing, Hearing, and Walking in your Patients Shoes: An Aging Simulation

Melissa Madden is an Assistant Professor in the Division of Nursing at Louisiana Tech University. Mary Wilson is an Instructor in the Division of Nursing at Louisiana Tech University

Characteristics of temporal fluctuations in the hyperpolarized state of the cortical slow oscillation

We present evidence for the hypothesis that transitions between the low- and high-firing states of the cortical slow oscillation correspond to neuronal phase transitions. By analyzing intracellular recordings of the membrane potential during the cortical slow oscillation in rats, we quantify the temporal fluctuations in power and the frequency centroid of the power spectrum in the period of time before “down” to “up” transitions. By taking appropriate averages over such events, we present these statistics as a function of time before transition. The results demonstrate an increase in fluctuation power and time scale broadly consistent with the slowing of systems close to phase transitions. The analysis is complicated and limited by the difficulty in identifying when transitions begin, and removing dc trends in membrane potential

Why misinformation is more likely to be recognized over time : a source monitoring account

Accepted ManuscriptAlthough memory for actual events tends to be forgotten over time, memory for misinformation tends to be retrieved at a stable rate over long delays or at a rate greater than that found immediately after encoding. To examine whether source monitoring errors contribute to this phenomenon, two experiments investigated subjects’ memory for the source of misinformation at different retention intervals. Subjects viewed a slide presentation, read a narrative containing misinformation, and, either 10 minutes or 1 week later, completed a recognition test about details seen in the slides and about the source of these details. After the longer retention interval in both experiments, participants were more likely to agree that they had seen misleading information and were also more likely to incorrectly associate the misinformation with the slide event. Theoretical implications of these findings are considered.Frost, P., Ingraham, M., & Wilson, B. (2002). Why misinformation is more likely to be recognised over time: A source monitoring account. Memory, 10(3), 179-185. doi:10.1080/0965821014300031