The multivariate asymptotic distribution of sequential Chi-square test statistics is investigated. It is shown that: (a) when sequential Chi-square statistics are calculated for nested models on the same data, the statistics have an asymptotic intercorrelation which may be expressed in closed form, and which is, in many cases, quite high; and (b) sequential Chi-square difference tests are asymptotically independent. Some Monte Carlo evidence on the applicability of the theory is provided.

Gastrointestinal and mental disorders are highly comorbid, and animal models have shown that both can be caused by early adversity (e.g., parental deprivation). Interactions between the brain and bacteria that live within the gastrointestinal system (the microbiome) underlie adversity–gastrointestinal–anxiety interactions, but these links have not been investigated during human development. In this study, we utilized data from a population of 344 youth (3–18 years old) who were raised with their biological parents or were exposed to early adverse caregiving experiences (i.e., institutional or foster care followed by international adoption) to explore adversity–gastrointestinal–anxiety associations. In Study 1, we demonstrated that previous adverse care experiences were associated with increased incidence of gastrointestinal symptoms in youth. Gastrointestinal symptoms were also associated with concurrent and future anxiety (measured across 5 years), and those gastrointestinal symptoms mediated the adversity–anxiety association at Time 1. In a subsample of children who provided both stool samples and functional magnetic resonance imaging of the brain (Study 2, which was a “proof-of-principle”), adversity was associated with changes in diversity (both alpha and beta) of microbial communities, and bacteria levels (adversity-associated and adversity-independent) were correlated with prefrontal cortex activation to emotional faces. Implications of these data for supporting youth mental health are discussed.

Institutional caregiving is associated with significant deviations from species-expected caregiving, altering the normative sequence of attachment formation and placing children at risk for long-term emotional difficulties. However, little is known about factors that can promote resilience following early institutional caregiving. In the current study, we investigated how adaptations in affective processing (i.e., positive valence bias) and family-level protective factors (i.e., secure parent–child relationships) moderate risk for internalizing symptoms in previously institutionalized (PI) youth. Children and adolescents with and without a history of institutional care performed a laboratory-based affective processing task and self-reported measures of parent–child relationship security. PI youth were more likely than comparison youth to show positive valence biases when interpreting ambiguous facial expressions. Both positive valence bias and parent–child relationship security moderated the association between institutional care and parent-reported internalizing symptoms, such that greater positive valence bias and more secure parent–child relationships predicted fewer symptoms in PI youth. However, when both factors were tested concurrently, parent–child relationship security more strongly moderated the link between PI status and internalizing symptoms. These findings suggest that both individual-level adaptations in affective processing and family-level factors of secure parent–child relationships may ameliorate risk for internalizing psychopathology following early institutional caregiving.

Vancomycin-resistant enterococci (VRE) infections are a public health threat associated with increased patient mortality and healthcare costs. Antibiotic usage, particularly cephalosporins, has been associated with VRE colonization and VRE bloodstream infections (VRE BSI). We examined the relationship between antimicrobial usage and incident VRE colonization at the individual patient level. Prospective, weekly surveillance was undertaken for incident VRE colonization defined by negative admission but positive surveillance swab in a medical intensive care unit over a 17-month period. Antimicrobial exposure was quantified as days of therapy (DOT)/1000 patient-days. Multiple logistic regression was used to analyse incident VRE colonization and antibiotic DOT, controlling for demographic and clinical covariates. Ninety-six percent (1398/1454) of admissions were swabbed within 24 h of intensive care unit (ICU) arrival and of the 380 patients in the ICU long enough for weekly surveillance, 83 (22%) developed incident VRE colonization. Incident colonization was associated in bivariate analysis with male gender, more previous hospital admissions, longer previous hospital stay, and use of cefepime/ceftazidime, fluconazole, azithromycin, and metronidazole (P < 0·05). After controlling for demographic and clinical covariates, metronidazole was the only antibiotic independently associated with incident VRE colonization (odds ratio 2·0, 95% confidence interval 1·2–3·3, P < 0·009). Our findings suggest that risk of incident VRE colonization differs between individual antibiotic agents and support the possibility that antimicrobial stewardship may impact VRE colonization and infection.

We investigated how third party managers from China, Japan and the USA intervened in employees' disputes. Consistent with predictions, we found (using non-linear HLM analysis) that managers who were superiors to the disputants behaved autocratically and/or decided on conservative (e.g., contract adhering) outcomes; but managers who were peers (especially in China and the USA), generally involved disputants in decision-making and obtained integrative outcomes that went beyond initial contract related mandates. Our results extend prior research and theorizing using the dispositional and constructivist perspectives on culture by introducing norm complexity as an explanation for variations in third party conflict intervention behaviour within one culture.

Chronic communal conflicts often embody prisoner's dilemmas. Both communities prefer peace to war. Yet neither trusts the other, viewing the other's gain as its loss, so potentially shared interests often go unrealized. Achieving positive-sum outcomes from apparently zero-sum struggles requires a particular kind of risk-embracing leadership. To succeed leaders must (a) see power relations as potentially positive-sum, (b) strengthen negotiating adversaries when tempted to weaken them, and (c) demonstrate hope for a positive future and take great personal risks to achieve it. Such leadership is exemplified by Nelson Mandela and F. W. de Klerk in the South African democratic transition. To illuminate the strategic dilemmas Mandela and de Klerk faced, we examine the work of Robert Axelrod, Thomas Schelling, and Josep Colomer, who highlight important dimensions of the problem but underplay the role of risk-embracing leadership. Finally we discuss leadership successes and failures in the Northern Ireland settlement and the Israeli-Palestinian conflict.

The secretion of prolactin and growth hormone (GH), together with subjective ratings of sedation and hunger, were determined in 13 in-patients with anorexia nervosa and 15 controls during the intravenous infusion of L-tryptophan (100 mg/kg). Prolactin responses were not different between groups but GH responses were markedly blunted in patients. In addition sedation responses in patients were attenuated compared with controls. Hunger ratings were reduced by the infusion in controls but were too variable to be interpreted in the patients. Plasma amino acid levels were also determined before and after infusion of L-tryptophan. Tryptophan levels were comparable in the two groups as were the levels of tyrosine, phenyl alanine, valine, leucine and iso-leucine. The results suggest that some aspects of 5-hydroxytryptamine function may be attenuated in anorexia nervosa. However, they undoubtedly contrast with the finding of enhanced hormonal responses in acute dieting and may be relevant to the interpretation of similar experiments in depressive illness.

A hybrid method for the problem of transient shock-induced filtration of the gas flow through granular media is developed. The hybrid method combines a controlled shock-tube test and Morrison's simplified approach to the problem of gas filtration. It is demonstrated that most pressure traces that have been recorded in various laboratories with a large variety of granular material samples and under different conditions are limited to situations in which the pressure losses in the flow are dominated by the Forchheimer mechanism. The hybrid method enables these results to be described by a single, universal pressure curve, and specification of the Forchheimer coefficient which is one of the two key parameters responsible for the correct simulation of the filtration-flow behaviour. The second key parameter, the Darcy coefficient, cannot be evaluated by the available experimental results. To overcome this shortcoming, a new controlled laboratory test that provides a wider range of the flow conditions, from the Forchheimer to the developed mixed flow, was conducted. In turn, a comprehensive gas dynamic analysis of the transient flow inside the shock tube enables us to define, from the single controlled laboratory test, the two coefficients of the Forchheimer resistance law, a and b.