Lifting accessible model structures

A Quillen model structure is presented by an interacting pair of weak factorization systems. We prove that in the world of locally presentable categories, any weak factorization system with accessible functorial factorizations can be lifted along either a left or a right adjoint. It follows that accessible model structures on locally presentable categories - ones admitting accessible functorial factorizations, a class that includes all combinatorial model structures but others besides - can be lifted along either a left or a right adjoint if and only if an essential "acyclicity" condition holds. A similar result was claimed in a paper of Hess-Kedziorek-Riehl-Shipley, but the proof given there was incorrect. In this note, we explain this error and give a correction, and also provide a new statement and a different proof of the theorem which is more tractable for homotopy-theoretic applications.Comment: This paper corrects an error in the proof of Corollary 3.3.4 of "A necessary and sufficient condition for induced model structures" arXiv:1509.0815

A Study of the Wellbeing of Siblings of Children with Autism Spectrum Disorders: Sibling Efficacy, Positive and Negative Affect, and Coping Strategies

Autism spectrum disorders (ASD) include pervasive developmental disorders characterised by communication deficits, difficulty with social understanding, and repetitive behaviors. Few studies have compared the efficacy, affect, and coping strategies of siblings of typically developing children with siblings of children with ASD. Typically developing siblings are understood to be at an increased risk of externalising and internalising problems. The current study examined whether siblings of children with ASD differed in levels of efficacy, affect, and coping from siblings of typically developing children. Participants (156) included an Australia-wide sample involving 82 siblings of children with ASD, and 74 siblings of typically developing individuals. Participants completed The Self-Efficacy Scale for Children (assessing social, emotional, and academic efficacy), the Positive and Negative Affect Scales, the Brief COPE Scale, and other scales as part of the larger study. Results showed that ASD siblings reported lower scores on emotional efficacy, social efficacy, and positive affect, and higher negative affect, than did the comparison group siblings. However, no significant differences were found in coping strategies or academic efficacy between the ASD siblings and the typically developing siblings. Consistent with earlier research findings, there are perceived negative effects or risks from being a sibling of an individual with ASD, suggesting support interventions may assist the development of emotional and social efficacy and increased positive affect for these individuals.</jats:p

Voluntary temporary abstinence from alcohol during “Dry January” and subsequent alcohol use

Objective: Temporary abstinence from alcohol may convey physiological benefits and enhance well-being. The aim of this study was to address a lack of information about: (1) correlates of successful completion of a planned period of abstinence, and (2) how success or failure in planned abstinence affects subsequent alcohol consumption. Methods: 857 British adults (249 men, 608 women) participating in the “Dry January” alcohol abstinence challenge completed a baseline questionnaire, a one-month follow-up questionnaire, and a 6-month follow-up questionnaire. Key variables assessed at baseline included measures of alcohol consumption and drink refusal self-efficacy (DRSE). Results: In bivariate analysis, success during Dry January was predicted by measures of more moderate alcohol consumption and greater social DRSE. Multivariate analyses revealed that success during Dry January was best predicted by a lower frequency of drunkenness in the month prior to Dry January. Structural Equation Modelling revealed that participation in Dry January was related to reductions in alcohol consumption and increases in DRSE among all respondents at 6-month follow-up, regardless of success, but these changes were more likely among people who successfully completed the challenge. Conclusions: The findings suggest that participation in abstinence challenges such as “Dry January” may be associated with changes toward healthier drinking and greater DRSE, and is unlikely to result in undesirable “rebound effects”: very few people reported increased alcohol consumption following a period of voluntary abstinence

Where Do New US-Trained Science-Engineering PhDs come from?

This study shows that the demographic and institutional origins of new US trained science and engineering PhDs changed markedly between the late 1960s-1970s to the 1990s-early 2000s. In 1966, 71% of science and engineering PhD graduates were US-born males, 6% were US-born females, and 23% were foreign born. In 2000, 36% of the graduates were US-born males, 25% were US-born females, and 39% were foreign born. Between 1970 and 2000 most of the growth in PhDs was in less prestigious smaller doctorate programs. The undergraduate origins of bachelor's obtaining science and engineering PhDs changed only modestly among US colleges and universities while there was a huge growth in the number of foreign bachelor's graduates obtaining US PhDs.

Ask a pathologist

This is a response to the question: I heard there is going to be a shortage of FFP [universal donor type AB plasma] from the American Red Cross during the next few months. What should I do when I need to urgently reverse anticoagulation in patients on warfarin

Representing moisture fluxes and phase changes in glacier debris cover using a reservoir approach

Due to the complexity of treating moisture in supraglacial debris, surface energy balance models to date have neglected moisture infiltration and phase changes in the debris layer. The latent heat flux (QL) is also often excluded due to the uncertainty in determining the surface vapour pressure. To quantify the importance of moisture on the surface energy and climatic mass balance (CMB) of debris-covered glaciers, we developed a simple reservoir parameterization for the debris ice and water content, as well as an estimation of the latent heat flux. The parameterization was incorporated into a CMB model adapted for debris-covered glaciers. We present the results of two point simulations, using both our new “moist” and the conventional “dry” approaches, on the Miage Glacier, Italy, during summer 2008 and fall 2011. The former year coincides with available in situ glaciological and meteorological measurements, including the first eddy-covariance measurements of the turbulent fluxes over supraglacial debris, while the latter contains two refreeze events that permit evaluation of the influence of phase changes. The simulations demonstrate a clear influence of moisture on the glacier energy and mass-balance dynamics. When water and ice are considered, heat transmission to the underlying glacier ice is lower, as the effective thermal diffusivity of the saturated debris layers is reduced by increases in both the density and the specific heat capacity of the layers. In combination with surface heat extraction by QL, subdebris ice melt is reduced by 3.1% in 2008 and by 7.0% in 2011 when moisture effects are included. However, the influence of the parameterization on the total accumulated mass balance varies seasonally. In summer 2008, mass loss due to surface vapour fluxes more than compensates for the reduction in ice melt, such that the total ablation increases by 4.0 %. Conversely, in fall 2011, the modulation of basal debris temperature by debris ice results in a decrease in total ablation of 2.1 %. Although the parameterization is a simplified representation of the moist physics of glacier debris, it is a novel attempt at including moisture in a numerical model of debris-covered glaciers and one that opens up additional avenues for future research

When Harvard Said No to Eugenics: The J. Ewing Mears Bequest, 1927

James Ewing Mears (1838-1919) was a founding member of the Philadelphia Academy of Surgery. His 1910 book, The Problem of Race Betterment, laid the groundwork for later authors to explore the uses of surgical sterilization as a eugenic measure. Mears left $60,000 in his will to Harvard University to support the teaching of eugenics. Although numerous eugenic activists were on the Harvard faculty, and who of its Presidents were also associated with the eugenics movement, Harvard refused the Mears gift. The bequest was eventually awarded to Jefferson Medical College in Philadelphia. This article explains why Harvard turned its back on a donation that would have supported instruction in a popular subject. Harvard\u27s decision illustrates the range of opinion that existed on the efficacy of eugenic sterilization at the time. The Mears case also highlights a powerful irony: the same week Harvard turned down the Mears legacy, the U.S. Supreme Court endorsed eugenic sterilization in the landmark case of Buck v. Bell. Justice Oliver Wendell Holmes, Jr., graduate of Harvard and former member of its law faculty wrote the opinion in that case, including the famous conclusion: Three generations of imbeciles are enough. Copyright © 2015, The John Hopkins University Press. This article first appeared in Perspectives in Biology and Medicine, Volume 57, Issue 3, Summer, 2014, pages 374-392