Neutron-neutron angular correlation in 252Cf spontaneous fission

The angular correlation between prompt neutrons emitted in 252 cf spontaneous fission has been measured. The observed correlation is compared with a theoretical calculation based on the evaporation model of neutron emission. It is found that the evaporation model is unable to account for the observed strong peaking in the n-n angular correlation at small angles. Preliminary calculations show that two of the proposed alternative neutron emission mechanisms, polar emission and "tidal wave" emission, may be able to account for the observed n-n angular correlation

Credibility of subgroup analyses by socioeconomic status in public health intervention evaluations:An underappreciated problem?

There is increasing interest amongst researchers and policy makers in identifying the effect of public health interventions on health inequalities by socioeconomic status (SES). This issue is typically addressed in evaluation studies through subgroup analyses, where researchers test whether the effect of an intervention differs according to the socioeconomic status of participants. The credibility of such analyses is therefore crucial when making judgements about how an intervention is likely to affect health inequalities, although this issue appears to be rarely considered within public health. The aim of this study was therefore to assess the credibility of subgroup analyses in published evaluations of public health interventions. An established set of 10 credibility criteria for subgroup analyses was applied to a purposively sampled set of 21 evaluation studies, the majority of which focussed on healthy eating interventions, which reported differential intervention effects by SES. While the majority of these studies were found to be otherwise of relatively high quality methodologically, only 8 of the 21 studies met at least 6 of the 10 credibility criteria for subgroup analysis. These findings suggest that the credibility of subgroup analyses conducted within evaluations of public health interventions’ impact on health inequalities may be an underappreciated problem. Keywords: Health inequalities, Health inequities, Equity and public health interventions, Policy impact by socioeconomic statu

Chondros crispus Stackhouse

The Northwest Atlantic Chondrus fishery is the basis of a phycocolloid industry. Harvesting is centered in the Gulfs of Maine and St. Lawrence where the species is an ecological dominant. The extensive ecological-physiological data base is reviewed as is the biosystematics. Annual catch peaked in 1974 (approx. 50,000 t) and troughed in 1983 (approx. 18,000 t). Catch decline was due/in part, to a decrease in crop demand caused by international marketplace competition from other carra-geenophytes. Harvesting and handling techniques are described. Resource management structure is outlined, as are stock assessment and assessment science programs. The international aspect of resource utilization is discussed

Drift by drift: effective population size is limited by advection

<p>Abstract</p> <p>Background</p> <p>Genetic estimates of effective population size often generate surprising results, including dramatically low ratios of effective population size to census size. This is particularly true for many marine species, and this effect has been associated with hypotheses of "sweepstakes" reproduction and selective hitchhiking.</p> <p>Results</p> <p>Here we show that in advective environments such as oceans and rivers, the mean asymmetric transport of passively dispersed reproductive propagules will act to limit the effective population size in species with a drifting developmental stage. As advection increases, effective population size becomes decoupled from census size as the persistence of novel genetic lineages is restricted to those that arise in a small upstream portion of the species domain.</p> <p>Conclusion</p> <p>This result leads to predictions about the maintenance of diversity in advective systems, and complements the "sweepstakes" hypothesis and other hypotheses proposed to explain cases of low allelic diversity in species with high fecundity. We describe the spatial extent of the species domain in which novel allelic diversity will be retained, thus determining how large an appropriately placed marine reserve must be to allow the persistence of endemic allelic diversity.</p

Repeated nasopharyngeal lavage predicts freedom from silent carriage of Streptococcus equi after a strangles outbreak

Background The value of repeated nasopharyngeal lavage (NPL) to detect silent carriers of Streptococcus equi has not been investigated. Hypothesis/Objectives Determine if results of serial testing for S. equi by NPL predicts subsequent true carrier status as determined by both NPL and guttural pouch lavage. Animals An outbreak of strangles with 100% morbidity in 41 mature Icelandic horses was followed prospectively to investigate development of silent carriers. All were initially positive to S. equi on NPL. The farm was closed to horse movement during the entire study. Methods Prospective observational study. Testing for S. equi was performed by NPL at weeks 18, 28, 29, and 30 postindex case and subsequently at week 45 by both NPL and guttural pouch lavage. Carrier status at week 45 was compared to results obtained at weeks 18, 28, 29, and 30. Descriptive statistics were calculated. Comparisons were made using Fisher's exact test or the Freeman-Halton extension with a P < .05 level of significance. Results Of 24 noncarriers at week 45, only 4 horses were negative on all 3 consecutive weekly NPL samples at weeks 28 to 30. However, 10 of the 11 horses with at least 3 negative NPL obtained from weeks 18, 28, 29, and 30 were S. equi-free at week 45 (P = .03). Conclusions and Clinical Importance Repeated NPL on at least 3 separate occasions can assist in predicting S. equi carrier-free status in horses after recovery from a strangles outbreak

ERdj5 is the ER reductase that catalyzes the removal of non-native disulfides and correct folding of the LDL receptor

ERdj5 is a member of the protein disulfide isomerase family of proteins localized to the endoplasmic reticulum (ER) of mammalian cells. To date, only a limited number of substrates for ERdj5 are known. Here we identify a number of endogenous substrates that form mixed disulfides with ERdj5, greatly expanding its client repertoire. ERdj5 previously had been thought to exclusively reduce disulfides in proteins destined for dislocation to the cytosol for degradation. However, we demonstrate here that for one of the identified substrates, the low-density lipoprotein receptor (LDLR), ERdj5 is required not for degradation, but rather for efficient folding. Our results demonstrate that the crucial role of ERdj5 is to reduce non-native disulfides formed during productive folding and that this requirement is dependent on its interaction with BiP. Hence, ERdj5 acts as the ER reductase, both preparing misfolded proteins for degradation and catalyzing the folding of proteins that form obligatory non-native disulfides

Assembly and Maturation of a T = 4 Quasi-Equivalent Virus Is Guided by Electrostatic and Mechanical Forces

Nudaurelia capensis w virus (NωV) is a eukaryotic RNA virus that is well suited for the study of virus maturation. The virus initially assembles at pH 7.6 into a marginally stable 480-Å procapsid formed by 240 copies of a single type of protein subunit. During maturation, which occurs during apoptosis at pH 5.0, electrostatic forces guide subunit trajectories into a robust 410-Å virion that is buttressed by subunit associated molecular switches. We discuss the competing factors in the virus capsid of requiring near-reversible interactions during initial assembly to avoid kinetic traps, while requiring robust stability to survive in the extra-cellular environment. In addition, viruses have a variety of mechanisms to deliver the genome, which must remain off while still inside the infected cell, yet turn on under the proper conditions of infection. We conclude that maturation is the process that provides a solution to these conflicting requirements through a program that is encoded in the procapsid and that leads to stability and infectivity

Editorial overview

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28647/1/0000462.pd

Influence of horse stable environment on human airways

This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens