Debris disks around Sun-like stars

We have observed nearly 200 FGK stars at 24 and 70 microns with the Spitzer Space Telescope. We identify excess infrared emission, including a number of cases where the observed flux is more than 10 times brighter than the predicted photospheric flux, and interpret these signatures as evidence of debris disks in those systems. We combine this sample of FGK stars with similar published results to produce a sample of more than 350 main sequence AFGKM stars. The incidence of debris disks is 4.2% (+2.0/-1.1) at 24 microns for a sample of 213 Sun-like (FG) stars and 16.4% (+2.8/-2.9) at 70 microns for 225 Sun-like (FG) stars. We find that the excess rates for A, F, G, and K stars are statistically indistinguishable, but with a suggestion of decreasing excess rate toward the later spectral types; this may be an age effect. The lack of strong trend among FGK stars of comparable ages is surprising, given the factor of 50 change in stellar luminosity across this spectral range. We also find that the incidence of debris disks declines very slowly beyond ages of 1 billion years.Comment: ApJ, in pres

TGF-b2 induction regulates invasiveness of theileria-transformed leukocytes and disease susceptibility

Theileria parasites invade and transform bovine leukocytes causing either East Coast fever (T. parva), or tropical theileriosis (T. annulata). Susceptible animals usually die within weeks of infection, but indigenous infected cattle show markedly reduced pathology, suggesting that host genetic factors may cause disease susceptibility. Attenuated live vaccines are widely used to control tropical theileriosis and attenuation is associated with reduced invasiveness of infected macrophages in vitro. Disease pathogenesis is therefore linked to aggressive invasiveness, rather than uncontrolled proliferation of Theileria-infected leukocytes. We show that the invasive potential of Theileria-transformed leukocytes involves TGF-b signalling. Attenuated live vaccine lines express reduced TGF-b2 and their invasiveness can be rescued with exogenous TGF-b. Importantly, infected macrophages from disease susceptible Holstein-Friesian (HF) cows express more TGF-b2 and traverse Matrigel with great efficiency compared to those from disease-resistant Sahiwal cattle. Thus, TGF-b2 levels correlate with disease susceptibility. Using fluorescence and time-lapse video microscopy we show that Theileria-infected, disease-susceptible HF macrophages exhibit increased actin dynamics in their lamellipodia and podosomal adhesion structures and develop more membrane blebs. TGF-b2-associated invasiveness in HF macrophages has a transcription-independent element that relies on cytoskeleton remodelling via activation of Rho kinase (ROCK). We propose that a TGF-b autocrine loop confers an amoeboid-like motility on Theileria-infected leukocytes, which combines with MMP-dependent motility to drive invasiveness and virulence

SARS-CoV Pathogenesis Is Regulated by a STAT1 Dependent but a Type I, II and III Interferon Receptor Independent Mechanism

Severe acute respiratory syndrome coronavirus (SARS-CoV) infection often caused severe end stage lung disease and organizing phase diffuse alveolar damage, especially in the elderly. The virus-host interactions that governed development of these acute end stage lung diseases and death are unknown. To address this question, we evaluated the role of innate immune signaling in protection from human (Urbani) and a recombinant mouse adapted SARS-CoV, designated rMA15. In contrast to most models of viral pathogenesis, infection of type I, type II or type III interferon knockout mice (129 background) with either Urbani or MA15 viruses resulted in clinical disease outcomes, including transient weight loss, denuding bronchiolitis and alveolar inflammation and recovery, identical to that seen in infection of wildtype mice. This suggests that type I, II and III interferon signaling play minor roles in regulating SARS pathogenesis in mouse models. In contrast, infection of STAT1−/− mice resulted in severe disease, high virus titer, extensive pulmonary lesions and 100% mortality by day 9 and 30 post-infection with rMA15 or Urbani viruses, respectively. Non-lethal in BALB/c mice, Urbani SARS-CoV infection in STAT1−/− mice caused disseminated infection involving the liver, spleen and other tissues after day 9. These findings demonstrated that SARS-CoV pathogenesis is regulated by a STAT1 dependent but type I, II and III interferon receptor independent, mechanism. In contrast to a well documented role in innate immunity, we propose that STAT1 also protects mice via its role as an antagonist of unrestrained cell proliferation

Rotavirus NSP1 Inhibits NFκB Activation by Inducing Proteasome-Dependent Degradation of β-TrCP: A Novel Mechanism of IFN Antagonism

Mechanisms by which viruses counter innate host defense responses generally involve inhibition of one or more components of the interferon (IFN) system. Multiple steps in the induction and amplification of IFN signaling are targeted for inhibition by viral proteins, and many of the IFN antagonists have direct or indirect effects on activation of latent cytoplasmic transcription factors. Rotavirus nonstructural protein NSP1 blocks transcription of type I IFNα/β by inducing proteasome-dependent degradation of IFN-regulatory factors 3 (IRF3), IRF5, and IRF7. In this study, we show that rotavirus NSP1 also inhibits activation of NFκB and does so by a novel mechanism. Proteasome-mediated degradation of inhibitor of κB (IκBα) is required for NFκB activation. Phosphorylated IκBα is a substrate for polyubiquitination by a multisubunit E3 ubiquitin ligase complex, Skp1/Cul1/F-box, in which the F-box substrate recognition protein is β-transducin repeat containing protein (β-TrCP). The data presented show that phosphorylated IκBα is stable in rotavirus-infected cells because infection induces proteasome-dependent degradation of β-TrCP. NSP1 expressed in isolation in transiently transfected cells is sufficient to induce this effect. Targeted degradation of an F-box protein of an E3 ligase complex with a prominent role in modulation of innate immune signaling and cell proliferation pathways is a unique mechanism of IFN antagonism and defines a second strategy of immune evasion used by rotaviruses

Expertise in evaluating choreographic creativity: an online adaptation of the Consensual Assessment Technique

In contemporary dance, experts evaluate creativity in competitions, auditions, and performances, typically through ratings of choreography or improvisation. Audiences also implicitly evaluate choreographic creativity, so dancers' livelihoods also hinge upon the opinions of non-expert observers. However, some argue that the abstract and often pedestrian nature of contemporary dance confuses non-expert audiences. Therefore, agreement regarding creativity and appreciation amongst experts and non-experts may be low. Finding appropriate methodologies for reliable and real-world creativity evaluation remains the subject of considerable debate within the psychology creativity research field. Although considerably variant in methodological operationalisation, the Consensual Assessment Technique (CAT) asks individuals to use an implicit definition to assess creativity in others' work. This study aimed to investigate the role of experience and expertise in the evaluation of Contemporary Dance, with a secondary aim of testing the feasibility of an online snowballing methodology for large-scale dance-specific research, informed by the methodology of the CAT. We filmed 23 Contemporary Dance students each performing a 3-minute solo choreography and then recruited 850 online evaluators with varying degrees of expertise and experience in dance and creativity. Evaluators viewed at least one randomly selected video and rated creativity, technical ability, appreciation and understanding of the work, each using a seven-point Likert scale. A one-way ANOVA showed a significant difference in creativity ratings across the 23 videos, and creativity correlated significantly with the other variables. We then categorised evaluators on nine aspects of their dance and creative experience and entered the data into a repeated-measures linear mixed model. Two of the fixed effects yielded differences in creativity evaluations: (i) contemporary choreographic experience and (ii) self-reported creative expertise, as did the random effect of the video. The results indicate that personal experience of the choreographic process impacts creativity assessment, above and beyond experience in dance class participation. Implications for creativity assessment within creativity research and practice are discussed

New genetic loci link adipose and insulin biology to body fat distribution.

Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms

Microbial and geochemical characterization of a contaminated freshwater ecosystem (the case of Vidy Bay, Lake Geneva, Switzerland)

Le Léman représente la plus grande réserve d'eau douce d'Europe Occidentale et fournit de l'eau à environ 700 000 personnes. Il s'agit d'un lac tempéré, monomictique, qui était considéré comme eutrophe dans les années 1970 à 1980, mais qui depuis est redevenu mésotrophe grâce à des réductions drastiques des apports en phosphore. Dû à un accroissement de la population, au développement de l'industrie et une agriculture plus intensive durant ces dernières décennies, certaines parties du lac souffrent de pollution d'origine anthropique. La ville de Lausanne, située sur la rive nord, déverse dans le lac les plus gros volumes d'eaux usées et traitées, au niveau de la Baie de Vidy. Les trois principales sources de contamination de cette baie sont les effluents de la station d'épuration de Vidy (STEP) et les embouchures des rivières Chamberonne et Flon. L'objectif principal de cette étude de thèse était d'évaluer et de caractériser la contamination chimique et microbiologique de la baie de Vidy, et d'étudier en particulier les effets de la pollution sur la composition et la diversité des populations microbiennes dans les sédiments. Les résultats de cette recherche confirment que les sédiments autour de l'exutoire de la STEP sont extrêmement riches en matière organique, nutriments, métaux-lourds et polluants organiques. Depuis 1996, une amélioration au niveau de la qualité des sédiments a été observée pour tous les métaux, à l'exception du mercure. Les teneurs en métaux sont cependant toujours très élevés autour de l'exutoire de la STEP, avec par exemple une valeur de mercure atteignant 8.7 mg kg-1. Ces valeurs étaient 3 à 13 fois plus élevées que les PELs ("probable effect levels"), mentionnés dans les directives canadiennes concernant la qualité des sédiments et la protection de la vie aquatique (CCME EPC-98E, 1999). Cela nous indique que ces sédiments contaminés ont certainement des effets toxiques sur la faune et la flore du lac. La diversité microbienne des sédiments contaminés de la Baie de Vidy est significativement moins importante que dans les sédiments non contaminés du lac. Les résultats de cette thèse suggèrent donc, que la pollution d'origine anthropique, en plus des paramètres environnementaux, peut affecter la composition et la diversité des populations bactériennes dans les sédiments

The impact of a sewage treatment plant's effluent on sediment quality in a small bay in Lake Geneva (Switzerland–France). Part 2: Temporal evolution of heavy metals

The Bay of Vidy is the most contaminated area of Lake Geneva, Switzerland, as a result of the release of treated and untreated waste water from the municipal sewage treatment plant of the city of Lausanne and its surroundings. The reconstruction of the historical deposition of heavy metals in the sediment of the bay has been performed by the analysis of several dated (radiocaesium)sediment cores. The presence of sewage-derived contaminants in the Bay of Vidy since the beginning of the sewage treatment plant's operations in 1964 is clearly observed, when a sharp increase in heavy metal contents is recorded, with maximum concentrations of cadmium, copper, zinc and lead occurring between the late 1960s and early 1970s. Despite considerable improvement in recent times, the present concentrations of the investigated heavy metals in sediments of the Bay of Vidy are still higher than concentrations measured at the centre of the lake, the latter close to Lake Geneva's natural background values. It is concluded that the quantity of heavy metals deposited in the bay is considerable and, because of sediment instability, will constitute a potential hazard for biota

Effects of a sewage treatment plant outlet pipe extension on the distribution of contaminants in the sediments of the Bay of Vidy, Lake Geneva, Switzerland

In 2001, the municipality of Lausanne extended the outlet pipe of the sewage treatment plant into the Bay of Vidy (Lake Geneva, Switzerland) as a measure to reduce bacterial water pollution and sediment contamination close to the lake beaches. The aim of the present study was to assess the impact of this measure. Lake bottom sediments were collected and analyzed for grain size, organic matter, organic carbon, nitrogen, phosphorus, heavy metals and hydrophobic organic compounds to evaluate their concentration and spatial distribution. Our results demonstrate that, compared to results obtained before the outlet pipe prolongation, the surface area of highly contaminated sediments was reduced by one third after the pipe extension. However, contaminant concentrations are still high and the accumulation of pollutants may represent a significant source of toxicity for benthic organisms. One concludes that contaminant reduction at the source will be necessary for a further improvement