SZE Observables, Pressure Profiles and Center Offsets in Magneticum Simulation Galaxy Clusters

We present a detailed study of the galaxy cluster thermal \ac{sze} signal $Y$ and pressure profiles using {\it Magneticum} Pathfinder hydrodynamical simulations. With a sample of 50,000 galaxy clusters ($M_{\rm 500c}>1.4\times10^{14} \rm M_{\odot}$) out to $z=2$, we find significant variations in the shape of the pressure profile with mass and redshift and present a new generalized NFW model that follows these trends. We show that the thermal pressure at $R_{\rm 500c}$ accounts for only 80~percent of the pressure required to maintain hydrostatic equilibrium, and therefore even idealized hydrostatic mass estimates would be biased at the 20~percent level. We compare the cluster \ac{sze} signal extracted from a sphere with different virial-like radii, a virial cylinder within a narrow redshift slice and the full light cone, confirming small scatter ($\sigma_{\ln Y}\simeq 0.087$) in the sphere and showing that structure immediately surrounding clusters increases the scatter and strengthens non self-similar redshift evolution in the cylinder. Uncorrelated large scale structure along the line of sight leads to an increase in the \ac{sze} signal and scatter that is more pronounced for low mass clusters, resulting in non self-similar trends in both mass and redshift and a mass dependent scatter that is $\sim0.16$ at low masses. The scatter distribution is consistent with log-normal in all cases. We present a model of the offsets between the center of the gravitational potential and the \ac{sze} center that follows the variations with cluster mass and redshift.Comment: 20 pages, 15 figures, submitted to MNRA

Why we should stop using the Kogut and Singh Index

The Kogut and Singh (J Int Bus Stud 19(3):411–432, 1988) index is the most widely used construct to measure cultural distance in international business and management research. We show that this index is incorrectly specified and captures the squared cultural distance. This inaccuracy is problematic because it means that the empirical findings on the effects of cultural distance presented in different strands of international business research are likely to be misleading. We specify the correct form of the distance measure based on the Euclidean distance formula and demonstrate the implications of using the incorrectly specified Kogut and Singh (1988) index

Nonexecutive direct influence on informational asymmetries in offshore financial centres

Question/issue: this is a study of the relationship between nonexecutive director personal ownership and firm's bid ask spreads in listed firms from across the Caribbean offshore securities exchanges. Research findings/insights: we report that bid ask spreads increase with nonexecutive ownership. However, this result is reduced (negatively moderated) in the context of higher formal institutional quality and also if the territory has a fixed exchange rate regime but exacerbated (positively moderated) if the firm is located within an offshore jurisdiction. Theoretical/academic implications: the results regarding the influence of nonexecutive director ownership on firm liquidity-based transaction costs, namely, market estimates of bid ask spreads, are interpreted in terms of the contingency of this relationship on the wider institutional context. The effectiveness of nonexecutive directors is highly contingent upon the specific institutional context. Higher formal institutional quality and the presence of a strong macroeconomic tie between territory and Organisation for Economic Co-operation and Development (OECD) country lead to a reduction in these costs, while offshore financial centers lead to their increase. We argue that this highlights a shortcoming of agency theory's more limited view of institutions. Practitioner/policy implications: the results support regulator's focus on board of director composition and in particular nonexecutive remuneration in the form of ownership. Given the increasing dominance of Anglo-American governance, firms worldwide are increasing the proportions of nonexecutive directors on their boards. However, their role is acutely context specific which is reflected in the relationship between their personal ownership and the liquidity-borne transaction costs of the firm as a whole.</p

Cultural bridging and the performance of international joint ventures

The existing predictions and findings regarding the effect of cultural distance on the performance of international joint ventures (IJVs) remain inconsistent. We suggest that this inconsistency is due to the lack of conceptually differentiating the cultural distance between the firm’s home country and its partner(s)’country (home-partner country cultural distance) from the cultural distance between the firm’s home country and the location of the IJV (home-host cultural distance). We contribute to our understanding of IJVs by explicitly differentiating these two types of cultural distance, and by introducing the concept of cultural bridging. Cultural bridging relates to the proportion of home-host cultural distance that is compensated by having a joint venture partner, whose home country culture is more similar to the host country culture than the MNE’s home country culture is to the host country culture. We theorize how cultural bridging affects IJV performance and how it interacts with home-partner country cultural distance and home-host cultural distance to influence IJV performance. We test our hypotheses using a sample of 1708 IJVs. We find that cultural bridging has a positive influence on IJV performance, strengthens the positive performance effect of home-host cultural distance, and reduces the negative performance effect of home-partner country cultural distance. Our findings help make sense of some of the inconsistent findings regarding the role that cultural distance plays for IJV performance

TB case detection in Tajikistan – analysis of existing obstacles

Background: Tajikistan National TB Control ProgramObjective: (1) To identify the main obstacles to increasing TB Detection in Tajikistan. (2) To identify interventions that improve TB detection.Methods: Review of the available original research data, health normative base, health systems performance and national economic data, following WHO framework for detection of TB cases, which is based on three scenarios of why incident cases of TB may not be notified.Results: Data analysis revealed that some aspects of TB case detection are more problematic than others and that there are gaps in the knowledge of specific obstacles to TB case detection. The phenomenon of “initial default” in Tajikistan has been documented; however, it needs to be studied further. The laboratory services detect infectious TB cases effectively; however, referrals of appropriate suspects for TB diagnosis may lag behind. The knowledge about TB in the general population has improved. Yet, the problem of TB related stigma persists, thus being an obstacle for effective TB detection. High economic cost of health services driven by under-the-table payments was identified as another barrier for access to health services.Conclusion: Health system strengthening should become a primary intervention to improve case detection in Tajikistan. More research on reasons contributing to the failure to register TB cases, as well as factors underlying stigma is needed

Schizotypy as An Organizing Framework for Social and Affective Sciences

Schizotypy, defined in terms of commonly occurring personality traits related to the schizophrenia spectrum, has been an important construct for understanding the neurodevelopment and stress-diathesis of schizophrenia. However, as schizotypy nears its sixth decade of application, it is important to acknowledge its impressively rich literature accumulating outside of schizophrenia research. In this article, we make the case that schizotypy has considerable potential as a conceptual framework for understanding individual differences in affective and social functions beyond those directly involved in schizophrenia spectrum pathology. This case is predicated on (a) a burgeoning literature noting anomalies in a wide range of social functioning, affiliative, positive and negative emotional, expressive, and social cognitive systems, (b) practical and methodological features associated with schizotypy research that help facilitate empirical investigation, and (c) close ties to theoretical constructs of central importance to affective and social science (eg, stress diathesis, neural compensation). We highlight recent schizotypy research, ie providing insight into the nature of affective and social systems more generally. This includes current efforts to clarify the neurodevelopmental, neurobiological, and psychological underpinnings of affiliative drives, hedonic capacity, social cognition, and stress responsivity systems. Additionally, we discuss neural compensatory and resilience factors that may mitigate the expression of stress-diathesis and functional outcome, and highlight schizotypy's potential role for understanding cultural determinants of social and affective function

Explaining alternative termination modes of international joint ventures

Purpose The authors combine options logic with transaction cost economics to explain why firms maintain, divest or buy out their international joint ventures (IJVs). It is suggested that a decline in environmental risk and higher partner-related risk makes a firm more likely to acquire an IJV but less likely to divest an IJV. The study also investigates how IJV age moderates the effects of a decline in environmental risk and higher partner-related risk. Design/methodology/approach The study employs competing risks analyses to examine the drivers of different termination outcomes using a dataset consisting of 459 IJVs in the People's Republic of China, of which 110 were either acquired or divested by their foreign parent. Findings The study finds that changes in environmental risk and partner-related risk affect how firms terminate their IJVs in the People's Republic of China. Specifically, the authors find that the effect of exogenous and endogenous risk are more pronounced for the acquisition of IJVs than for the divestment of IJVs. Research limitations/implications The study contributes to international marketing research by complementing options logic with transaction cost economics to provide a theoretical explanation of the different ways in which IJVs in the People's Republic of China are terminated. Practical implications IJVs continue to be an important yet often unstable method to serve international markets. Our findings increase managers' awareness of the effect that two important sources of risk may have on the termination of IJVs in the People's Republic of China. Originality/value The study provides novel insights into the effect that changes in exogenous and endogenous risk have on a firm's choice of termination mode drawing on novel data on the different ways in which foreign firms have terminated their IJVs in the Peoples' Republic of China

A systematic scoping review of study methodology for randomized controlled trials investigating probiotics in athletic and physically active populations

Background: The purported ergogenic and health effects of probiotics have been a topic of great intrigue among researchers, practitioners, and the lay public alike. There has also been an increased research focus within the realm of sports science and exercise medicine on the athletic gut microbiota. However, compared to other ergogenic aids and dietary supplements, probiotics present unique study challenges. The objectives of this systematic scoping review were to identify and characterize study methodologies of randomized controlled trials investigating supplementation with probiotics in athletes and physically active individuals. Methods: Four databases (MEDLINE, CINAHL, Cochrane CENTRAL, and Cochrane Database of Systematic Reviews) were searched for randomized controlled studies involving healthy athletes or physically active individuals. An intervention with probiotics and inclusion of a control and/or placebo group were essential. Only peer-reviewed articles in English were considered, and there were no date restrictions. Results were extracted and presented in tabular form to detail study protocols, characteristics, and outcomes. Bias in randomized controlled trials was determined with the RoB 2.0 tool. Results: A total of 45 studies were included in the review, with 35 using a parallel group design and 10 using a cross-over design. Approximately half the studies used a single probiotic and the other half a multi-strain preparation. The probiotic dose ranged from 2 × 108 to 1 × 1011 colony forming units daily, and the length of intervention was between 7 and 150 days. Fewer than half the studies directly assessed gastrointestinal symptoms, gut permeability, or the gut microbiota. The sex ratio of participants was heavily weighted toward males, and only 3 studies exclusively investigated females. Low-level adverse events were reported in only 2 studies, although the methodology of reporting varied widely. The risk of bias was generally low, although details on randomization were lacking in some studies. Conclusion: There is a substantial body of research on the effects of probiotic supplementation in healthy athletes and physically active individuals. Considerable heterogeneity in probiotic selection and dosage as well as outcome measures has made clinical and mechanistic interpretation challenging for both health care practitioners and researchers. Attention to issues of randomization of participants, treatments and interventions, selection of outcomes, demographics, and reporting of adverse events will facilitate more trustworthy interpretation of probiotic study results and inform evidence-based guidelines

Cognition and Brain Function in Schizotypy: A Selective Review

Schizotypy refers to a set of personality traits thought to reflect the subclinical expression of the signs and symptoms of schizophrenia. Here, we review the cognitive and brain functional profile associated with high questionnaire scores in schizotypy. We discuss empirical evidence from the domains of perception, attention, memory, imagery and representation, language, and motor control. Perceptual deficits occur early and across various modalities. While the neural mechanisms underlying visual impairments may be linked to magnocellular dysfunction, further effects may be seen downstream in higher cognitive functions. Cognitive deficits are observed in inhibitory control, selective and sustained attention, incidental learning, and memory. In concordance with the cognitive nature of many of the aberrations of schizotypy, higher levels of schizotypy are associated with enhanced vividness and better performance on tasks of mental rotation. Language deficits seem most pronounced in higher-level processes. Finally, higher levels of schizotypy are associated with reduced performance on oculomotor tasks, resembling the impairments seen in schizophrenia. Some of these deficits are accompanied by reduced brain activation, akin to the pattern of hypoactivations in schizophrenia spectrum individuals. We conclude that schizotypy is a construct with apparent phenomenological overlap with schizophrenia and stable interindividual differences that covary with performance on a wide range of perceptual, cognitive, and motor tasks known to be impaired in schizophrenia. The importance of these findings lies not only in providing a fine-grained neurocognitive characterization of a personality constellation known to be associated with real-life impairments, but also in generating hypotheses concerning the aetiology of schizophreni

Toward Unbiased Galaxy Cluster Masses from Line of Sight Velocity Dispersions

We study the use of red sequence selected galaxy spectroscopy for unbiased estimation of galaxy cluster masses. We use the publicly available galaxy catalog produced using the semi-analytic model of De Lucia & Blaizot (2007) on the Millenium Simulation (Springel et al. 2005). We explore the impacts on selection using galaxy color, projected separation from the cluster center, and galaxy luminosity. We study the relationship between cluster mass and velocity dispersion and identify and characterize the following sources of bias and scatter: halo triaxiality, dynamical friction of red luminous galaxies and interlopers. We show that due to halo triaxiality the intrinsic scatter of estimated line of sight dynamical mass is about three times larger (30-40%) than the one estimated using the 3D velocity dispersion (~12%) and a small bias (~1%) is induced. We find evidence of increasing scatter as a function of redshift and provide a fitting formula to account for it. We characterize the amount of bias and scatter introduced by dynamical friction when using subsamples of red-luminous galaxies to estimate the velocity dispersion. We study the presence of interlopers in spectroscopic samples and their effect on the estimated cluster dynamical mass. Our results show that while cluster velocity dispersions extracted from a few dozen red sequence selected galaxies do not provide precise masses on a single cluster basis, an ensemble of cluster velocity dispersions can be combined to produce a precise calibration of a cluster survey mass observable relation. Currently, disagreements in the literature on simulated subhalo velocity dispersion mass relations place a systematic floor on velocity dispersion mass calibration at the 15% level in mass. We show that the selection related uncertainties are small by comparison, providing hope that with further improvements this systematic floor can be reduced.Comment: submitted to Ap