The effect of flares on total solar irradiance

Flares are powerful energy releases occurring in stellar atmospheres. Solar flares, the most intense energy bursts in the solar system, are however hardly noticeable in the total solar luminosity. Consequently, the total amount of energy they radiate 1) remains largely unknown and 2) has been overlooked as a potential contributor to variations in the Total Solar Irradiance (TSI), i.e. the total solar flux received at Earth. Here, we report on the detection of the flare signal in the TSI even for moderate flares. We find that the total energy radiated by flares exceeds the soft X-ray emission by two orders of magnitude, with an important contribution in the visible domain. These results have implications for the physics of flares and the variability of our star.Comment: accepted in Nature Physic

Identifying sources, pathways and risk drivers in ecosystems of Japanese Encephalitis in an epidemic-prone north Indian district

Japanese Encephalitis (JE) has caused repeated outbreaks in endemic pockets of India. This study was conducted in Kushinagar, a highly endemic district, to understand the human-animal-ecosystem interactions, and the drivers that influence disease transmission. Utilizing the ecosystems approach, a cross-sectional, descriptive study, employing mixed methods design was employed. Four villages (two with pig-rearing and two without) were randomly selected from a high, a medium and a low burden (based on case counts) block of Kushinagar. Children, pigs and vectors were sampled from these villages. A qualitative arm was incorporated to explain the findings from the quantitative surveys. All human serum samples were screened for JE-specific IgM using MAC ELISA and negative samples for JE RNA by rRT-PCR in peripheral blood mononuclear cells. In pigs, IgG ELISA and rRT-PCR for viral RNA were used. Of the 242 children tested, 24 tested positive by either rRT-PCR or MAC ELISA; in pigs, 38 out of the 51 pigs were positive. Of the known vectors, Culex vishnui was most commonly isolated across all biotopes. Analysis of 15 blood meals revealed human blood in 10 samples. Univariable analysis showed that gender, religion, lack of indoor residual spraying of insecticides in the past year, indoor vector density (all species), and not being vaccinated against JE in children were significantly associated with JE positivity. In multivariate analysis, only male gender remained as a significant risk factor. Based on previous estimates of symptomatic: asymptomatic cases of JE, we estimate that there should have been 618 cases from Kushinagar, although only 139 were reported. Vaccination of children and vector control measures emerged as major control activities; they had very poor coverage in the studied villages. In addition, lack of awareness about the cause of JE, lack of faith in the conventional medical healthcare system and multiple referral levels causing delay in diagnosis and treatment emerged as factors likely to result in adverse clinical outcomes

A Candidate Subspecies Discrimination System Involving a Vomeronasal Receptor Gene with Different Alleles Fixed in M. m. domesticus and M. m. musculus

Assortative mating, a potentially efficient prezygotic reproductive barrier, may prevent loss of genetic potential by avoiding the production of unfit hybrids (i.e., because of hybrid infertility or hybrid breakdown) that occur at regions of secondary contact between incipient species. In the case of the mouse hybrid zone, where two subspecies of Mus musculus (M. m. domesticus and M. m. musculus) meet and exchange genes to a limited extent, assortative mating requires a means of subspecies recognition. We based the work reported here on the hypothesis that, if there is a pheromone sufficiently diverged between M. m. domesticus and M. m. musculus to mediate subspecies recognition, then that process must also require a specific receptor(s), also sufficiently diverged between the subspecies, to receive the signal and elicit an assortative mating response. We studied the mouse V1R genes, which encode a large family of receptors in the vomeronasal organ (VNO), by screening Perlegen SNP data and identified one, Vmn1r67, with 24 fixed SNP differences most of which (15/24) are nonsynonymous nucleotide substitutions between M. m. domesticus and M. m. musculus. We observed substantial linkage disequilibrium (LD) between Vmn1r67 and Abpa27, a mouse salivary androgen-binding protein gene that encodes a proteinaceous pheromone (ABP) capable of mediating assortative mating, perhaps in conjunction with its bound small lipophilic ligand. The LD we observed is likely a case of association rather than residual physical linkage from a very recent selective sweep, because an intervening gene, Vmn1r71, shows significant intra(sub)specific polymorphism but no inter(sub)specific divergence in its nucleotide sequence. We discuss alternative explanations of these observations, for example that Abpa27 and Vmn1r67 are coevolving as signal and receptor to reinforce subspecies hybridization barriers or that the unusually divergent Vmn1r67 allele was not a product of fast positive selection, but was derived from an introgressed allele, possibly from Mus spretus

The atm-1 gene is required for genome stability in Caenorhabditis elegans

The Ataxia-telangiectasia-mutated (ATM) gene in humans was identified as the basis of a rare autosomal disorder leading to cancer susceptibility and is now well known as an important signal transducer in response to DNA damage. An approach to understanding the conserved functions of this gene is provided by the model system, Caenorhabditis elegans. In this paper we describe the structure and loss of function phenotype of the ortholog atm-1. Using bioinformatic and molecular analysis we show that the atm-1 gene was previously misannotated. We find that the transcript is in fact a product of three gene predictions, Y48G1BL.2 (atm-1), K10E9.1, and F56C11.4 that together make up the complete coding region of ATM-1. We also characterize animals that are mutant for two available knockout alleles, gk186 and tm5027. As expected, atm-1 mutant animals are sensitive to ionizing radiation. In addition, however, atm-1 mutants also display phenotypes associated with genomic instability, including low brood size, reduced viability and sterility. We document several chromosomal fusions arising from atm-1 mutant animals. This is the first time a mutator phenotype has been described for atm-1 in C. elegans. Finally we demonstrate the use of a balancer system to screen for and capture atm-1-derived mutational events. Our study establishes C. elegans as a model for the study of ATM as a mutator potentially leading to the development of screens to identify therapeutic targets in humans

Physical activity and colon cancer prevention: a meta-analysis

Although an inverse association between physical activity and risk of colon cancer is well established, a formal estimate of the magnitude of this risk reduction that includes recent studies is not available. This analysis examines the association by sex and study design, restricting analyses to studies where data for colon cancer alone were available. The authors reviewed published studies through June 2008 examining the association between physical activity and risk of colon cancer. Heterogeneity and publication bias were evaluated and random effects models used to estimate relative risks (RR). Differences by sex and study design were evaluated. A total of 52 studies were included. An inverse association between physical activity and colon cancer was found with an overall relative risk (RR) of 0.76 (95% confidence interval (CI): 0.72, 0.81). For men, the RR was 0.76 (95% CI: 0.71, 0.82); for women, this was little different, (RR=0.79, 95% CI: 0.71, 0.88). The findings from case–control studies were stronger (RR=0.69, 95% CI: 0.65, 0.74) than for cohort studies (RR=0.83, 95% CI: 0.78, 0.88). This study confirms previous studies reporting an inverse association between physical activity and colon cancer in both men and women, and provides quantitative estimates of the inverse association

New semiquantitative ultrasonographic score for peripheral arterial disease assessment and its association with cardiovascular risk factors

The data concerning the distribution, extent and progression of peripheral arterial disease (PAD), as well as its association with traditional cardiovascular (CV) risk factors, have generally been obtained from studies of patients in advanced stages of the disease undergoing surgical or endovascular treatment. In this study, we have introduced a new semiquantitative ultrasonographic score (ultrasonographic lower limb atherosclerosis (ULLA) score) that is able to categorize lower limb atherosclerotic lesions at all stages of PAD. We then associated these ultrasonographic categories with a CV risk profile. We enrolled 320 consecutive subjects with symptoms suggestive of PAD or with known CV risk factors referring to our angiology unit between 1 July 2014 and 30 June 2015 for ultrasonographic evaluation of the lower limb arteries. Femoropopliteal and run-off segments were categorized together and separately based on their ultrasonographic characteristics. In univariate and multivariate analyses, the ULLA scores were significantly associated with the main CV risk factors, that is, age, male gender, cigarette smoking, arterial hypertension, diabetes, dyslipidemia, sedentary lifestyle, previous CV events and family history of CV disease, and also confirming the specific association of single risk factors with different segments of lower limb arteries. The proposed ULLA score enables a complete evaluation of the entire lower limb atherosclerotic burden, extending the results concerning the association of PAD with CV risk factors to all stages of the disease, including the early stages. It can be feasible that this new score will facilitate better evaluation of the progression of PAD and its prospective role in CV risk stratification

Dietary iron intake in the first 4 months of infancy and the development of type 1 diabetes: a pilot study

<p>Abstract</p> <p>Aims</p> <p>To investigate the impact of iron intake on the development of type 1 diabetes (T1DM).</p> <p>Methods</p> <p>Case-control study with self-administered questionnaire among families of children with T1DM who were less than 10 years old at the time of the survey and developed diabetes between age 1 and 6 years. Data on the types of infant feeding in the first 4 months of life was collected from parents of children with T1DM (n = 128) and controls (n = 67) <10 years old. Because some cases had sibling controls, we used conditional logistic regression models to analyze the data in two ways. First we performed a case-control analysis of all 128 cases and 67 controls. Next, we performed a case-control analysis restricted to cases (n = 59) that had a sibling without diabetes (n = 59). Total iron intake was modeled as one standard deviation (SD) increase in iron intake. The SD for iron intake was 540 mg in the total sample and 539 mg in the restricted sample as defined above.</p> <p>Results</p> <p>The median (min, max) total iron intake in the first 4 months of life was 1159 (50, 2399) mg in T1DM cases and 466 (50, 1224) mg among controls (<it>P </it>< 0.001). For each one standard deviation increase in iron intake, the odds ratio (95% confidence interval) for type 1 diabetes was 2.01 (1.183, 3.41) among all participants (128 cases and 67 controls) while it was 2.26 (1.27, 4.03) in a restricted sample of T1 D cases with a control sibling (59 cases and 59 controls) in models adjusted for birth weight, age at the time of the survey, and birth order.</p> <p>Conclusion</p> <p>In this pilot study, high iron intake in the first 4 months of infancy is associated with T1DM. Whether iron intake is causal or a marker of another risk factor warrants further investigation.</p

Chemical diplomacy in male tilapia: urinary signal increases sex hormone and decreases aggression

Androgens, namely 11-ketotestosterone (11KT), have a central role in male fish reproductive physiology and are thought to be involved in both aggression and social signalling. Aggressive encounters occur frequently in social species, and fights may cause energy depletion, injury and loss of social status. Signalling for social dominance and fighting ability in an agonistic context can minimize these costs. Here, we test the hypothesis of a 'chemical diplomacy' mechanism through urinary signals that avoids aggression and evokes an androgen response in receiver males of Mozambique tilapia (Oreochromis mossambicus). We show a decoupling between aggression and the androgen response; males fighting their mirror image experience an unresolved interaction and a severe drop in urinary 11KT. However, if concurrently exposed to dominant male urine, aggression drops but urinary 11KT levels remain high. Furthermore, 11KT increases in males exposed to dominant male urine in the absence of a visual stimulus. The use of a urinary signal to lower aggression may be an adaptive mechanism to resolve disputes and avoid the costs of fighting. As dominance is linked to nest building and mating with females, the 11KT response of subordinate males suggests chemical eavesdropping, possibly in preparation for parasitic fertilizations.info:eu-repo/semantics/publishedVersio

Novel Insights into the Diversity of Catabolic Metabolism from Ten Haloarchaeal Genomes

BACKGROUND: The extremely halophilic archaea are present worldwide in saline environments and have important biotechnological applications. Ten complete genomes of haloarchaea are now available, providing an opportunity for comparative analysis. METHODOLOGY/PRINCIPAL FINDINGS: We report here the comparative analysis of five newly sequenced haloarchaeal genomes with five previously published ones. Whole genome trees based on protein sequences provide strong support for deep relationships between the ten organisms. Using a soft clustering approach, we identified 887 protein clusters present in all halophiles. Of these core clusters, 112 are not found in any other archaea and therefore constitute the haloarchaeal signature. Four of the halophiles were isolated from water, and four were isolated from soil or sediment. Although there are few habitat-specific clusters, the soil/sediment halophiles tend to have greater capacity for polysaccharide degradation, siderophore synthesis, and cell wall modification. Halorhabdus utahensis and Haloterrigena turkmenica encode over forty glycosyl hydrolases each, and may be capable of breaking down naturally occurring complex carbohydrates. H. utahensis is specialized for growth on carbohydrates and has few amino acid degradation pathways. It uses the non-oxidative pentose phosphate pathway instead of the oxidative pathway, giving it more flexibility in the metabolism of pentoses. CONCLUSIONS: These new genomes expand our understanding of haloarchaeal catabolic pathways, providing a basis for further experimental analysis, especially with regard to carbohydrate metabolism. Halophilic glycosyl hydrolases for use in biofuel production are more likely to be found in halophiles isolated from soil or sediment