Quasi-Chemical and Structural Analysis of Polarizable Anion Hydration

Quasi-chemical theory is utilized to analyze the roles of solute polarization and size in determining the structure and thermodynamics of bulk anion hydration for the Hofmeister series Cl$^-$, Br$^-$, and I$^-$. Excellent agreement with experiment is obtained for whole salt hydration free energies using the polarizable AMOEBA force field. The quasi-chemical approach exactly partitions the solvation free energy into inner-shell, outer-shell packing, and outer-shell long-ranged contributions by means of a hard-sphere condition. Small conditioning radii, even well inside the first maximum of the ion-water(oxygen) radial distribution function, result in Gaussian behavior for the long-ranged contribution that dominates the ion hydration free energy. The spatial partitioning allows for a mean-field treatment of the long-ranged contribution, leading to a natural division into first-order electrostatic, induction, and van der Waals terms. The induction piece exhibits the strongest ion polarizability dependence, while the larger-magnitude first-order electrostatic piece yields an opposing but weaker polarizability dependence. In addition, a structural analysis is performed to examine the solvation anisotropy around the anions. As opposed to the hydration free energies, the solvation anisotropy depends more on ion polarizability than on ion size: increased polarizability leads to increased anisotropy. The water dipole moments near the ion are similar in magnitude to bulk water, while the ion dipole moments are found to be significantly larger than those observed in quantum mechanical studies. Possible impacts of the observed over-polarization of the ions on simulated anion surface segregation are discussed.Comment: slight revision, in press at J. Chem. Phy

The Magnetic Rayleigh-Taylor Instability in Three Dimensions

We study the magnetic Rayleigh-Taylor instability in three dimensions, with focus on the nonlinear structure and evolution that results from different initial field configurations. We study strong fields in the sense that the critical wavelength l_c at which perturbations along the field are stable is a large fraction of the size of the computational domain. We consider magnetic fields which are initially parallel to the interface, but have a variety of configurations, including uniform everywhere, uniform in the light fluid only, and fields which change direction at the interface. Strong magnetic fields do not suppress instability, in fact by inhibiting secondary shear instabilities, they reduce mixing between the heavy and light fluid, and cause the rate of growth of bubbles and fingers to increase in comparison to hydrodynamics. Fields parallel to, but whose direction changes at, the interface produce long, isolated fingers separated by the critical wavelength l_c, which may be relevant to the morphology of the optical filaments in the Crab nebula.Comment: 14 pages, 9 pages, accepted by Ap

Recruiting Sources and Posthire Outcomes for Job Applicants and New Hires: A Test of Two Hypotheses

This study, unlike most recruitment source research, tested for and ruled out the contaminating effects of prescreening and self-selection bias by examining applicants and new hires for nursing positions (S. L. Rynes and A. E. Barber, 1990). Consistent with the predictions of A. Rees (1966) and J. C. Ullman (1966), recruitment sources reached differently qualified applicants in terms of nursing experience and education which, in turn, were valid predictors of subsequent nurse performance. In a similar manner, recruitment sources produced sharply different levels of prehire knowledge, which was inversely related to voluntary turnover after 1 yr. However, contrary to both hypotheses, prehire knowledge, education, and experience did not mediate the relationship between recruitment sources and posthire outcomes. Recruitment sources with greater prehire knowledge did not always result in lower voluntary turnover. Likewise, despite recruitment source differences in nursing experience and education, recruitment sources were not related to nursing performance. Finally, the extent to which applicants use multiple recruitment sources was investigated, and the methodological problem that this creates for recruitment source research was discussed

A novel mechanism of RNase L inhibition: Theiler\u27s virus L* protein prevents 2-5A from binding to RNase L

<div><p>The OAS/RNase L pathway is one of the best-characterized effector pathways of the IFN antiviral response. It inhibits the replication of many viruses and ultimately promotes apoptosis of infected cells, contributing to the control of virus spread. However, viruses have evolved a range of escape strategies that act against different steps in the pathway. Here we unraveled a novel escape strategy involving Theiler’s murine encephalomyelitis virus (TMEV) L* protein. Previously we found that L* was the first viral protein binding directly RNase L. Our current data show that L* binds the ankyrin repeats R1 and R2 of RNase L and inhibits 2’-5’ oligoadenylates (2-5A) binding to RNase L. Thereby, L* prevents dimerization and oligomerization of RNase L in response to 2-5A. Using chimeric mouse hepatitis virus (MHV) expressing TMEV L*, we showed that L* efficiently inhibits RNase L <i>in vivo</i>. Interestingly, those data show that L* can functionally substitute for the MHV-encoded phosphodiesterase ns2, which acts upstream of L* in the OAS/RNase L pathway, by degrading 2-5A.</p></div

Prevalence of Inherited Hemoglobin Disorders and Relationships with Anemia and Micronutrient Status among Children in Yaoundé and Douala, Cameroon.

Information on the etiology of anemia is necessary to design effective anemia control programs. Our objective was to measure the prevalence of inherited hemoglobin disorders (IHD) in a representative sample of children in urban Cameroon, and examine the relationships between IHD and anemia. In a cluster survey of children 12-59 months of age (n = 291) in Yaoundé and Douala, we assessed hemoglobin (Hb), malaria infection, and plasma indicators of inflammation and micronutrient status. Hb S was detected by HPLC, and α⁺thalassemia (3.7 kb deletions) by PCR. Anemia (Hb &lt; 110 g/L), inflammation, and malaria were present in 45%, 46%, and 8% of children. A total of 13.7% of children had HbAS, 1.6% had HbSS, and 30.6% and 3.1% had heterozygous and homozygous α⁺thalassemia. The prevalence of anemia was greater among HbAS compared to HbAA children (60.3 vs. 42.0%, p = 0.038), although mean Hb concentrations did not differ, p = 0.38). Hb and anemia prevalence did not differ among children with or without single gene deletion α⁺thalassemia. In multi-variable models, anemia was independently predicted by HbAS, HbSS, malaria, iron deficiency (ID; inflammation-adjusted ferritin &lt;12 µg/L), higher C-reactive protein, lower plasma folate, and younger age. Elevated soluble transferrin receptor concentration (&gt;8.3 mg/L) was associated with younger age, malaria, greater mean reticulocyte counts, inflammation, HbSS genotype, and ID. IHD are prevalent but contribute modestly to anemia among children in urban Cameroon

Electrostatic Solar Sail: A Propellantless Propulsion Concept for an Interstellar Probe Mission

The propulsion of an electrostatic solar sail (E Sail) is obtained by extracting momentum from the solar wind through electrostatic repulsion of the positively charged solar wind ions (see Figure 1). The positively charged solar wind protons are deflected by the electric field created around the tethers.This electric field grows in diameter as the spacecraft moves away from the Sun, therefore the E Sail effective area grows. The growth of the E-Sail effective area allows the propulsive force to decrease as 1/r up to distances of 20 AU as it moves away from the Sun, unlike solar sail propulsion whose thrust decreases as 1/r 2 but only to distances of 5AU. This propulsive force is created without using propellant and, therefore, E-sail avoids both the mass and complexity of chemical rockets (that require large amounts of propellant, propellant storage tanks, plumbing, valves, and insulation)

Moral wrongs, disadvantages, and disability: a critique of critical disability studies

Critical disability studies (CDS) has emerged as an approach to the study of disability over the last decade or so and has sought to present a challenge to the predominantly materialist line found in the more conventional disability studies approaches. In much the same way that the original development of the social model resulted in a necessary correction to the overly individualized accounts of disability that prevailed in much of the interpretive accounts which then dominated medical sociology, so too has CDS challenged the materialist line of disability studies. In this paper we review the ideas behind this development and analyse and critique some of its key ideas. The paper starts with a brief overview of the main theorists and approaches contained within CDS and then moves on to normative issues; namely, to the ethical and political applicability of CDS

FGF21 mediates the thermogenic and insulin-sensitizing effects of dietary methionine restriction but not its effects on hepatic lipid metabolism

© 2017 by the American Diabetes Association. Dietary methionine restriction (MR) produces a rapid and persistent remodeling of white adipose tissue (WAT), an increase in energy expenditure (EE), and enhancement of insulin sensitivity. Recent work established that hepatic expression of FGF21 is robustly increased by MR. Fgf212/2 mice were used to test whether FGF21 is an essential mediator of the physiological effects of dietary MR. The MR-induced increase in energy intake and EE and activation of thermogenesis in WAT and brown adipose tissue were lost in Fgf212/2 mice. However, dietary MR produced a comparable reduction in body weight and adiposity in both genotypes because of a negative effect of MR on energy intake in Fgf212/2 mice. Despite the similar loss in weight, dietary MR produced a more significant increase in in vivo insulin sensitivity in wild-Type than in Fgf212/2 mice, particularly in heart and inguinal WAT. In contrast, the ability of MR to regulate lipogenic and integrated stress response genes in liver was not compromised in Fgf212/2 mice. Collectively, these findings illustrate that FGF21 is a critical mediator of the effects of dietary MR on EE, remodeling of WAT, and increased insulin sensitivity but not of its effects on hepatic gene expression

Predicting academic misconduct intentions and behavior using the theory of planned behavior and personality

This is an Accepted Manuscript of an article published by Taylor & Francis in Basic and Applied Social Psychology on February 23, 2010, available online: https://www.tandfonline.com/doi/abs/10.1080/01973530903539895?journalCode=hbas20The efficacy of Azjen’s (1985; 1991) Theory of Planned Behavior (TPB) for the prediction of cheating intentions and behaviors was examined in a sample of 241 business undergraduates. Mediated structural equation models of the TPB, with personality constructs, adjustment and prudence, as antecedents were examined. The TPB model explained 21% of the variance in cheating intentions and 36% of cheating behavior. Results support both the TPB model and a partially mediated model in which prudence, but not adjustment, is significantly related to model components, attitudes, norms, control and behavior but not intention to cheat. These results suggest the TPB model may parsimoniously integrate and advance academic misconduct research. Further TPB research and practical implications are discussed.Ye

Academic integrity: The relationship between individual and situational factors on misconduct contemplations

The version of record of this article, first published in Journal of Business Ethics, is available online at Publisher’s website: https://link.springer.com/article/10.1007/s10551-006-9260-9Recent, well-publicized scandals, involving unethical conduct have rekindled interest in academic misconduct. Prior studies of academic misconduct have focused exclusively on situational factors (e.g., integrity culture, honor codes), demographic variables or personality constructs. We contend that it is important to also examine how these classes of variables interact to influence perceptions of and intentions relating to academic misconduct. In a sample of business students, we examined how integrity culture interacts with Prudence and Adjustment to explain variance in estimated frequency of cheating, suspicions of cheating, considering cheating and reporting cheating. Age, integrity culture, and personality variables were significantly related to different criteria. Overall, personality variables explained the most unique variance in academic misconduct, and Adjustment interacted with integrity culture, such that integrity culture had more influence on intentions to cheat for less well adjusted individuals. Implications for practice are discussed and future research directions are offered.Ye