Floral temperature and optimal foraging: is heat a feasible floral reward for pollinators?

As well as nutritional rewards, some plants also reward ectothermic pollinators with warmth. Bumble bees have some control over their temperature, but have been shown to forage at warmer flowers when given a choice, suggesting that there is some advantage to them of foraging at warm flowers (such as reducing the energy required to raise their body to flight temperature before leaving the flower). We describe a model that considers how a heat reward affects the foraging behaviour in a thermogenic central-place forager (such as a bumble bee). We show that although the pollinator should spend a longer time on individual flowers if they are warm, the increase in total visit time is likely to be small. The pollinator's net rate of energy gain will be increased by landing on warmer flowers. Therefore, if a plant provides a heat reward, it could reduce the amount of nectar it produces, whilst still providing its pollinator with the same net rate of gain. We suggest how heat rewards may link with plant life history strategies

NOT THE LAST RESORT: the impact of an interprofessional training care home on residents, care home staff, and students

Care homes are a fundamental part of the health and social care system, and with demand in thesector expected to increase, it is important to better understand how the sector can improverecruitment and retention, be sustainably staffed, and promote collaborative practice. Whileinterprofessional training environments are increasingly seen as a key stage in advancing health andsocial care systems, little is known about interprofessional student training schemes in the context ofthe UK care home environment. This pilot study aimed to implement and evaluate a 6-week IPEstudent training placement scheme across three care homes across in Greater Manchester. Students(n=15) across a variety of disciplines - including nursing, physiotherapy, social work, podiatry,counselling, and sports rehabilitation - were placed within the homes to work in an interprofessionalenvironment and address the goals of residents as a collaborative team. A total of 52 qualitative semistructured interviews were undertaken with residents (n=10), care home staff (n=12) and students(n=30), over a period of 5 months. Quantitative data was collected by administering an AGEINquestionnaire to students pre and post placement (n=13). The questionnaire asked students abouttheir perceptions of, and attitudes toward, working with older people. Our study suggests that carehomes provide students with an ideal environment for interprofessional working and learning. Throughbetter understanding the dimensions of difference perspectives and approaches, students felt theproject improved their education and shifted their perceptions of aged care. Staff benefit from newways of working, improving their knowledge and skills, which in turn enhances the care the residentsreceive. Findings also highlight the complex barriers that influence interprofessional learning in thecare home setting. In this report we will discuss the benefits and challenges of implementinginterprofessional education in care home settings, detail the positive and transformative impacts theexperience had on residents, staff and students and consider the future direction of such scheme

Mining and analysis of audiology data to find significant factors associated with tinnitus masker

Objectives: The objective of this research is to find the factors associated with tinnitus masker from the literature, and by using the large amount of audiology data available from a large NHS (National Health Services, UK) hearing aid clinic. The factors evaluated were hearing impairment, age, gender, hearing aid type, mould and clinical comments. Design: The research includes literature survey for factors associated with tinnitus masker, and performs the analysis of audiology data using statistical and data mining techniques. Setting: This research uses a large audiology data but it also faced the problem of limited data for tinnitus. Participants: It uses 1,316 records for tinnitus and other diagnoses, and 10,437 records of clinical comments from a hearing aid clinic. Primary and secondary outcome measures: The research is looking for variables associated with tinnitus masker, and in future, these variables can be combined into a single model to develop a decision support system to predict about tinnitus masker for a patient. Results: The results demonstrated that tinnitus maskers are more likely to be fit to individuals with milder forms of hearing loss, and the factors age, gender, type of hearing aid and mould were all found significantly associated with tinnitus masker. In particular, those patients having Age<=55 years were more likely to wear a tinnitus masker, as well as those with milder forms of hearing loss. ITE (in the ear) hearing aids were also found associated with tinnitus masker. A feedback on the results of association of mould with tinnitus masker from a professional audiologist of a large NHS (National Health Services, UK) was also taken to better understand them. The results were obtained with different accuracy for different techniques. For example, the chi-squared test results were obtained with 95% accuracy, for Support and Confidence only those results were retained which had more than 1% Support and 80% Confidence. Conclusions: The variables audiograms, age, gender, hearing aid type and mould were found associated with the choice of tinnitus masker in the literature and by using statistical and data mining techniques. The further work in this research would lead to the development of a decision support system for tinnitus masker with an explanation that how that decision was obtained

How predation and landscape fragmentation affect vole population dynamics

Background: Microtine species in Fennoscandia display a distinct north-south gradient from regular cycles to stable populations. The gradient has often been attributed to changes in the interactions between microtines and their predators. Although the spatial structure of the environment is known to influence predator-prey dynamics of a wide range of species, it has scarcely been considered in relation to the Fennoscandian gradient. Furthermore, the length of microtine breeding season also displays a north-south gradient. However, little consideration has been given to its role in shaping or generating population cycles. Because these factors covary along the gradient it is difficult to distinguish their effects experimentally in the field. The distinction is here attempted using realistic agent-based modelling. Methodology/Principal Findings: By using a spatially explicit computer simulation model based on behavioural and ecological data from the field vole (Microtus agrestis), we generated a number of repeated time series of vole densities whose mean population size and amplitude were measured. Subsequently, these time series were subjected to statistical autoregressive modelling, to investigate the effects on vole population dynamics of making predators more specialised, of altering the breeding season, and increasing the level of habitat fragmentation. We found that fragmentation as well as the presence of specialist predators are necessary for the occurrence of population cycles. Habitat fragmentation and predator assembly jointly determined cycle length and amplitude. Length of vole breeding season had little impact on the oscillations. Significance: There is good agreement between our results and the experimental work from Fennoscandia, but our results allow distinction of causation that is hard to unravel in field experiments. We hope our results will help understand the reasons for cycle gradients observed in other areas. Our results clearly demonstrate the importance of landscape fragmentation for population cycling and we recommend that the degree of fragmentation be more fully considered in future analyses of vole dynamics

Type II Secretory Phospholipase A2 and Prognosis in Patients with Stable Coronary Heart Disease: Mendelian Randomization Study

Serum type II secretory phospholipase A(2) (sPLA(2)-IIa) has been found to be predictive of adverse outcomes in patients with stable coronary heart disease. Compounds targeting sPLA(2)-IIa are already under development. This study investigated if an association of sPLA(2)-IIa with secondary cardiovascular disease (CVD) events may be of causal nature or mainly a matter of confounding by correlated cardiovascular risk markers.Eight-year follow-up data of a prospective cohort study (KAROLA) of patients who underwent in-patient rehabilitation after an acute cardiovascular event were analysed. Associations of polymorphisms (SNP) in the sPLA(2)-IIa-coding gene PLA2G2A with serum sPLA(2)-IIa and secondary fatal or non-fatal CVD events were examined by multiple regression. Hazard ratios (HR) were compared with those expected if the association between sPLA(2)-IIa and CVD were causal. The strongest determinants of sPLA(2)-IIa (rs4744 and rs10732279) were associated with an increase of serum concentrations by 81% and 73% per variant allele. HRs (95% confidence intervals) estimating the associations of the SNPs with secondary CVD events were increased, but not statistically significant (1.16 [0.89-1.51] and 1.18 [0.91-1.52] per variant allele, respectively). However, these estimates were very similar to those expected when assuming causality (1.18 and 1.17), based on an association of natural log-transformed sPLA(2)-IIa concentration with secondary events with HR = 1.33 per unit.The present findings regarding genetic polymorphisms, determination of serum sPLA(2)-IIa, and prognosis in CVD patients are consistent with a genuine causal relationship and thus might point to a valid drug target for prevention of secondary CVD events

Nucleotide and phylogenetic analyses of the Chlamydia trachomatis ompA gene indicates it is a hotspot for mutation

<p>Abstract</p> <p>Background</p> <p>Serovars of the human pathogen <it>Chlamydia trachomatis </it>occupy one of three specific tissue niches. Genomic analyses indicate that the serovars have a phylogeny congruent with their pathobiology and have an average substitution rate of less than one nucleotide per kilobase. In contrast, the gene that determines serovar specificity, <it>ompA</it>, has a phylogenetic association that is not congruent with tissue tropism and has a degree of nucleotide variability much higher than other genomic loci. The <it>ompA </it>gene encodes the major surface-exposed antigenic determinant, and the observed nucleotide diversity at the <it>ompA </it>locus is thought to be due to recombination and host immune selection pressure. The possible contribution of a localized increase in mutation rate, however, has not been investigated.</p> <p>Results</p> <p>Nucleotide diversity and phylogenetic relationships of the five constant and four variable domains of the <it>ompA </it>gene, as well as several loci surrounding <it>ompA</it>, were examined for each serovar. The loci flanking the <it>ompA </it>gene demonstrated that nucleotide diversity increased monotonically as <it>ompA </it>is approached and that their gene trees are not congruent with either <it>ompA </it>or tissue tropism. The variable domains of the <it>ompA </it>gene had a very high level of non-synonymous change, which is expected as these regions encode the surface-exposed epitopes and are under positive selection. However, the synonymous changes are clustered in the variable regions compared to the constant domains; if hitchhiking were to account for the increase in synonymous changes, these substitutions should be more evenly distributed across the gene. Recombination also cannot entirely account for this increase as the phylogenetic relationships of the constant and variable domains are congruent with each other.</p> <p>Conclusions</p> <p>The high number of synonymous substitutions observed within the variable domains of <it>ompA </it>appears to be due to an increased mutation rate within this region of the genome, whereas the increase in nucleotide substitution rate and the lack of phylogenetic congruence in the regions flanking <it>ompA </it>are characteristic motifs of gene conversion. Together, the increased mutation rate in the <it>ompA </it>gene, in conjunction with gene conversion and positive selection, results in a high degree of variability that promotes host immune evasion.</p

Cysteinyl-tRNA Deacylation Can Be Uncoupled from Protein Synthesis

Aminoacyl-tRNA synthetases (ARSs) are critical components of protein translation, providing ribosomes with aminoacyl-tRNAs. In return, ribosomes release uncharged tRNAs as ARS substrates. Here, we show that tRNA deacylation can be uncoupled from protein synthesis in an amino acid specific manner. While tRNAs coupled to radiolabeled Met, Leu Lys, or Ser are stable in cells following translation inhibition with arsenite, radiolabeled Cys is released from tRNA at a high rate. We discuss possible translation independent functions for tRNACys

Negative consequences associated with dependence in daily cannabis users

BACKGROUND: Cannabis is the most widely consumed illicit substance in America, with increasing rates of use. Some theorists tend to link frequency of use with cannabis dependence. Nevertheless, fewer than half of daily cannabis users meet DSM-IV-TR criteria for cannabis dependence. This study seeks to determine whether the negative aspects associated with cannabis use can be explained by a proxy measure of dependence instead of by frequency of use. RESULTS: Over 2500 adult daily cannabis users completed an Internet survey consisting of measures of cannabis and other drug use, in addition to measures of commonly reported negative problems resulting from cannabis use. We compared those who met a proxy measure of DSM-IV-TR criteria for cannabis dependence (N = 1111) to those who did not meet the criteria (N = 1770). Cannabis dependent subjects consumed greater amounts of cannabis, alcohol, and a variety of other drugs. They also had lower levels of motivation, happiness, and satisfaction with life, with higher levels of depression and respiratory symptoms. CONCLUSION: Although all of our subjects reported daily use, only those meeting proxy criteria for cannabis dependence reported significant associated problems. Our data suggest that dependence need not arise from daily use, but consuming larger amounts of cannabis and other drugs undoubtedly increases problems

Metabolic state alters economic decision making under risk in humans

Background: Animals' attitudes to risk are profoundly influenced by metabolic state (hunger and baseline energy stores). Specifically, animals often express a preference for risky (more variable) food sources when below a metabolic reference point (hungry), and safe (less variable) food sources when sated. Circulating hormones report the status of energy reserves and acute nutrient intake to widespread targets in the central nervous system that regulate feeding behaviour, including brain regions strongly implicated in risk and reward based decision-making in humans. Despite this, physiological influences per se have not been considered previously to influence economic decisions in humans. We hypothesised that baseline metabolic reserves and alterations in metabolic state would systematically modulate decision-making and financial risk-taking in humans. Methodology/Principal Findings: We used a controlled feeding manipulation and assayed decision-making preferences across different metabolic states following a meal. To elicit risk-preference, we presented a sequence of 200 paired lotteries, subjects' task being to select their preferred option from each pair. We also measured prandial suppression of circulating acyl-ghrelin (a centrally-acting orexigenic hormone signalling acute nutrient intake), and circulating leptin levels (providing an assay of energy reserves). We show both immediate and delayed effects on risky decision-making following a meal, and that these changes correlate with an individual's baseline leptin and changes in acyl-ghrelin levels respectively. Conclusions/Significance: We show that human risk preferences are exquisitely sensitive to current metabolic state, in a direction consistent with ecological models of feeding behaviour but not predicted by normative economic theory. These substantive effects of state changes on economic decisions perhaps reflect shared evolutionarily conserved neurobiological mechanisms. We suggest that this sensitivity in human risk-preference to current metabolic state has significant implications for both real-world economic transactions and for aberrant decision-making in eating disorders and obesity