2,039 research outputs found

    BORROWING BEHAVIOR UNDER FINANCIAL STRESS BY THE PROPRIETARY FIRM: A THEORETICAL ANALYSIS

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    This paper extends finance theory under risk to account for borrowing behavior under financial stress conditions. As the financial stress level for the firm increases, the role of credit or unused borrowing capacity changes. With a strong equity position, credit is valued as a reserve to avoid liquidation costs resulting from the sale of fixed assets to meet cash flow obligations. As the financial stress on the firm increases the model demonstrates the firmÂ’s willingness to reduce credit reserves and increase its financial leverage in order to increase its probability of survival. These results are derived in a tractable framework by describing risky alternatives in terms of expected values and variances.Financial Economics,

    Interaction of marital status and genetic risk for symptoms of depression

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    Extended twin study of alcohol use in Virginia and Australia

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    Drinking alcohol is a normal behavior in many societies, and prior studies have demonstrated it has both genetic and environmental sources of variation. Using two very large samples of twins and their first-degree relatives (Australia ≈ 20,000 individuals from 8,019 families; Virginia ≈ 23,000 from 6,042 families), we examine whether there are differences: (1) in the genetic and environmental factors that influence four interrelated drinking behaviors (quantity, frequency, age of initiation, and number of drinks in the last week), (2) between the twin-only design and the extended twin design, and (3) the Australian and Virginia samples. We find that while drinking behaviors are interrelated, there are substantial differences in the genetic and environmental architectures across phenotypes. Specifically, drinking quantity, frequency, and number of drinks in the past week have large broad genetic variance components, and smaller but significant environmental variance components, while age of onset is driven exclusively by environmental factors. Further, the twin-only design and the extended twin design come to similar conclusions regarding broad-sense heritability and environmental transmission, but the extended twin models provide a more nuanced perspective. Finally, we find a high level of similarity between the Australian and Virginian samples, especially for the genetic factors. The observed differences, when present, tend to be at the environmental level. Implications for the extended twin model and future directions are discussed

    Cross-cultural comparison of genetic and cultural transmission of smoking initiation using an extended twin kinship model

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    Background: Considerable evidence from twin and adoption studies indicates that genetic and shared environmental factors play a role in the initiation of smoking behavior. Although twin and adoption designs are powerful to detect genetic and environmental influences, they do not provide information on the processes of assortative mating and parent–offspring transmission and their contribution to the variability explained by genetic and/or environmental factors. Methods: We examined the role of genetic and environmental factors in individual differences for smoking initiation (SI) using an extended kinship design. This design allows the simultaneous testing of additive and non-additive genetic, shared and individual-specific environmental factors, as well as sex differences in the expression of genes and environment in the presence of assortative mating and combined genetic and cultural transmission, while also estimating the regression of the prevalence of SI on age. A dichotomous lifetime ‘ever’ smoking measure was obtained from twins and relatives in the ‘Virginia 30,000’ sample and the ‘Australian 25,000’. Results: Results demonstrate that both genetic and environmental factors play a significant role in the liability to SI. Major influences on individual differences appeared to be additive genetic and unique environmental effects, with smaller contributions from assortative mating, shared sibling environment, twin environment, cultural transmission, and resulting genotype-environment covariance. Age regression of the prevalence of SI was significant. The finding of negative cultural transmission without dominance led us to investigate more closely two possible mechanisms for the lower parent–offspring correlations compared to the sibling and DZ twin correlations in subsets of the data: (1) age × gene interaction, and (2) social homogamy. Neither of the mechanism provided a significantly better explanation of the data. Conclusions: This study showed significant heritability, partly due to assortment, and significant effects of primarily non-parental shared environment on liability to SI

    Comparison of the inhibition of an OCT3 transporter inhibitor, Nilotinib, on Doxorubicin’s effects on cardiac and cancer cell lines

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    Introduction Doxorubicin (DOX)-induced cardiotoxicity remains a significant barrier limiting its clinical application due to a lack of effective resolution. Targeting how DOX enters cardiac and cancer cells is a promising new strategy. Research suggests that an OCT3 transporter significantly contributes to DOX entry into the heart tissue. By contrast, it expresses much lower on breast cancer cell lines. Moreover, Nilotinib (NIB) can suppress OCT3 transporter function by 80%. Therefore, exploring the impact of NIB on the DOX’s effects on cardiac and cancer cell lines by altering DOX intracellular accumulation is intriguing. Objective First, we would establish a dose-response curve of DOX and NIB alone to assess their individual effects on cell viability. Secondly, we would record the impact of NIB on DOX entry within cardiac myoblasts (H9C2) and breast cancer cells (MCF7) through OCT3 transporter antagonism to assess if NIB can exert cardioprotective effects while maintaining DOX’s anticancer effect. Methods H9C2 myoblast and MCF7 breast cancer cells were seeded in 96-well black plates. Cells were treated with only DOX or NIB to establish a dose-response curve. Moreover, NIB was combined with DOX as a cotreatment or pretreatment regimen to evaluate the impacts of NIB on DOX’s effect. Titrated combinations of NIB (10 nM, 50 nM, 100 nM, 500 nM, 1 µM, 2 µM, 5 µM) and DOX (10 µM and 40µM) were used. Bioassays were conducted after cells were treated for 24 hours. Intracellular DOX fluorescence intensity was measured at 488/590 nm by fluoroskan. Subsequently, cell viability was detected by measuring absorbance at 450 nm after adding a cell counting reagent. The data were expressed as a ratio relative to untreated or the DOX control. Results DOX dose-dependently reduced viability of H9c2 and MCF7 cells. H9c2 cell showed significantly lower cell viability at 1 µM (0.86±0.04, n=10, p\u3c0.05) and 40 µM (0.40±0.02, n=10, p\u3c0.05) when compared to those of MCF7 cells (1.07±0.05 and 0.68±0.08 for 1 µM and 40 µM, respectively, n=7). By contrast, NIB (10 nM-2 µM) only slightly increased cell viability to 1.13±0.05 (n=11) in H9c2 cells and to 1.16±0.13 (n=7) in MCF7 cells, respectively, when compared to untreated control. The highest tested dose of NIB (5 µM) showed a similar reduction of cell viability to 0.83±0.07 in H9c2 cells and to 0.81±0.10 in MCF7 cells. Furthermore, NIB cotreatment mitigated DOX-induced damages in H9c2 by increasing cell viability to 1.28±0.07 (n=5) and 1.26±0.11 (n=7) when compared to the DOX controls (10 µM and 40µM), respectively. Interestingly, NIB cotreatment enhanced DOX’s anti-cancer effects in by decreasing MCF7 cell viability to 0.66±0.10 (n=7) and 0.70±0.09 (n=6) when compared to the DOX controls (10 µM and 40µM), respectively. The intracellular DOX fluorescence data and NIB pretreatment results are still being gathered. Conclusion DOX, not NIB, dose-dependently induced H9c2 and MCF7 cell death. Moreover, DOX-induced damage was more potent in H9c2 cells than in MCF7 cells. NIB cotreatment mildly protected H9c2 cells against DOX, whereas it increased DOX’s anti-cancer effects in MCF7 cells

    Males do not reduce the fitness of their female co-twins in contemporary samples.

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    Lummaa et al. (2007) presented historical data collected from twins born in Finland between 1734 and 1888 which suggested that females (N = 31) born as part of an opposite sex (OS) twin pair were 25% less likely to reproduce than female twins (N = 35) born as part of a same sex (SS) pair. They hypothesized that this reduction in fitness was due to masculinization of the female fetus via prenatal effects of the hormones of a male fetus. Because such masculinization would presumably take place in modern populations as well, it would seem important to establish to what degree it does so, and if so, whether reproduction is affected. We therefore address the question of reproduction differences in individual female twins from same-sex (N = 1979) and opposite-sex (N = 913) dizygotic pairs in studies carried out in Australia, the Netherlands, and the United States. In all three samples, there were no differences in the number of children or age of first pregnancies in women from same sex pairs compared to those from opposite sex pairs. Similarly, there were no differences in psychological femininity between women from pairs of the same or opposite sex

    The Vaginal Microbiome: Disease, Genetics and the Environment

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    The vagina is an interactive interface between the host and the environment. Its surface is covered by a protective epithelium colonized by bacteria and other microorganisms. The ectocervix is nonsterile, whereas the endocervix and the upper genital tract are assumed to be sterile in healthy women. Therefore, the cervix serves a pivotal role as a gatekeeper to protect the upper genital tract from microbial invasion and subsequent reproductive pathology. Microorganisms that cross this barrier can cause preterm labor, pelvic inflammatory disease, and other gynecologic and reproductive disorders. Homeostasis of the microbiome in the vagina and ectocervix plays a paramount role in reproductive health. Depending on its composition, the microbiome may protect the vagina from infectious or non-infectious diseases, or it may enhance its susceptibility to them. Because of the nature of this organ, and the fact that it is continuously colonized by bacteria from birth to death, it is virtually certain that this rich environment evolved in concert with its microbial flora. Specific interactions dictated by the genetics of both the host and microbes are likely responsible for maintaining both the environment and the microbiome. However, the genetic basis of these interactions in both the host and the bacterial colonizers is currently unknown. _Lactobacillus_ species are associated with vaginal health, but the role of these species in the maintenance of health is not yet well defined. Similarly, other species, including those representing minor components of the overall flora, undoubtedly influence the ability of potential pathogens to thrive and cause disease. Gross alterations in the vaginal microbiome are frequently observed in women with bacterial vaginosis, but the exact etiology of this disorder is still unknown. There are also implications for vaginal flora in non-infectious conditions such as pregnancy, pre-term labor and birth, and possibly fertility and other aspects of women’s health. Conversely, the role of environmental factors in the maintenance of a healthy vaginal microbiome is largely unknown. To explore these issues, we have proposed to address the following questions:

*1.	Do the genes of the host contribute to the composition of the vaginal microbiome?* We hypothesize that genes of both host and bacteria have important impacts on the vaginal microbiome. We are addressing this question by examining the vaginal microbiomes of mono- and dizygotic twin pairs selected from the over 170,000 twin pairs in the Mid-Atlantic Twin Registry (MATR). Subsequent studies, beyond the scope of the current project, may investigate which host genes impact the microbial flora and how they do so.
*2.	What changes in the microbiome are associated with common non-infectious pathological states of the host?* We hypothesize that altered physiological (e.g., pregnancy) and pathologic (e.g., immune suppression) conditions, or environmental exposures (e.g., antibiotics) predictably alter the vaginal microbiome. Conversely, certain vaginal microbiome characteristics are thought to contribute to a woman’s risk for outcomes such as preterm delivery. We are addressing this question by recruiting study participants from the ~40,000 annual clinical visits to women’s clinics of the VCU Health System.
*3.	What changes in the vaginal microbiome are associated with relevant infectious diseases and conditions?* We hypothesize that susceptibility to infectious disease (e.g. HPV, _Chlamydia_ infection, vaginitis, vaginosis, etc.) is impacted by the vaginal microbiome. In turn, these infectious conditions clearly can affect the ability of other bacteria to colonize and cause pathology. Again, we are exploring these issues by recruiting participants from visitors to women’s clinics in the VCU Health System.

Three kinds of sequence data are generated in this project: i) rDNA sequences from vaginal microbes; ii) whole metagenome shotgun sequences from vaginal samples; and iii) whole genome shotgun sequences of bacterial clones selected from vaginal samples. The study includes samples from three vaginal sites: mid-vaginal, cervical, and introital. The data sets also include buccal and perianal samples from all twin participants. Samples from these additional sites are used to test the hypothesis of a per continuum spread of bacteria in relation to vaginal health. An extended set of clinical metadata associated with these sequences are deposited with dbGAP. We have currently collected over 4,400 samples from ~100 twins and over 450 clinical participants. We have analyzed and deposited data for 480 rDNA samples, eight whole metagenome shotgun samples, and over 50 complete bacterial genomes. These data are available to accredited investigators according to NIH and Human Microbiome Project (HMP) guidelines. The bacterial clones are deposited in the Biodefense and Emerging Infections Research Resources Repository ("http://www.beiresources.org/":http://www.beiresources.org/). 

In addition to the extensive sequence data obtained in this study, we are collecting metadata associated with each of the study participants. Thus, participants are asked to complete an extensive health history questionnaire at the time samples are collected. Selected clinical data associated with the visit are also obtained, and relevant information is collected from the medical records when available. This data is maintained securely in a HIPAA-compliant data system as required by VCU’s Institutional Review Board (IRB). The preponderance of these data (i.e., that judged appropriate by NIH staff and VCU’s IRB are deposited at dbGAP ("http://www.ncbi.nlm.nih.gov/gap":http://www.ncbi.nlm.nih.gov/gap). Selected fields of this data have been identified by NIH staff as ‘too sensitive’ and are not available in dbGAP. Individuals requiring access to these data fields are asked to contact the PI of this project or NIH Program Staff. 
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    Green Plants in the Red: A Baseline Global Assessment for the IUCN Sampled Red List Index for Plants

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    Plants provide fundamental support systems for life on Earth and are the basis for all terrestrial ecosystems; a decline in plant diversity will be detrimental to all other groups of organisms including humans. Decline in plant diversity has been hard to quantify, due to the huge numbers of known and yet to be discovered species and the lack of an adequate baseline assessment of extinction risk against which to track changes. The biodiversity of many remote parts of the world remains poorly known, and the rate of new assessments of extinction risk for individual plant species approximates the rate at which new plant species are described. Thus the question ‘How threatened are plants?’ is still very difficult to answer accurately. While completing assessments for each species of plant remains a distant prospect, by assessing a randomly selected sample of species the Sampled Red List Index for Plants gives, for the first time, an accurate view of how threatened plants are across the world. It represents the first key phase of ongoing efforts to monitor the status of the world’s plants. More than 20% of plant species assessed are threatened with extinction, and the habitat with the most threatened species is overwhelmingly tropical rain forest, where the greatest threat to plants is anthropogenic habitat conversion, for arable and livestock agriculture, and harvesting of natural resources. Gymnosperms (e.g. conifers and cycads) are the most threatened group, while a third of plant species included in this study have yet to receive an assessment or are so poorly known that we cannot yet ascertain whether they are threatened or not. This study provides a baseline assessment from which trends in the status of plant biodiversity can be measured and periodically reassessed

    Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

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    This paper presents measurements of the W+μ+νW^+ \rightarrow \mu^+\nu and WμνW^- \rightarrow \mu^-\nu cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13
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