1,468 research outputs found

    Evolution in the Volumetric Type Ia Supernova Rate from the Supernova Legacy Survey

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    We present a measurement of the volumetric Type Ia supernova (SN Ia) rate (SNR_Ia) as a function of redshift for the first four years of data from the Canada-France-Hawaii Telescope Supernova Legacy Survey (SNLS). This analysis includes 286 spectroscopically confirmed and more than 400 additional photometrically identified SNe Ia within the redshift range 0.1 ≤ z ≤ 1.1. The volumetric SNR_Ia evolution is consistent with a rise to z ~ 1.0 that follows a power law of the form (1+z)^α, with α = 2.11 ± 0.28. This evolutionary trend in the SNLS rates is slightly shallower than that of the cosmic star formation history (SFH) over the same redshift range. We combine the SNLS rate measurements with those from other surveys that complement the SNLS redshift range, and fit various simple SN Ia delay-time distribution (DTD) models to the combined data. A simple power-law model for the DTD (i.e., ∝ t^(–β)) yields values from β = 0.98 ± 0.05 to β = 1.15 ± 0.08 depending on the parameterization of the cosmic SFH. A two-component model, where SNR_Ia is dependent on stellar mass (M_stellar) and star formation rate (SFR) as SNR_(Ia)(z) = A × M_(stellar)(z) + B × SFR(z), yields the coefficients A = (1.9 ± 0.1) × 10^(–1)4 SNe yr^(–1) M^(–1)_☉ and B = (3.3 ± 0.2) × 10^(–4) SNe yr^(–1) (M_☉ yr^(–1))^(–1). More general two-component models also fit the data well, but single Gaussian or exponential DTDs provide significantly poorer matches. Finally, we split the SNLS sample into two populations by the light-curve width (stretch), and show that the general behavior in the rates of faster-declining SNe Ia (0.8 ≤ s < 1.0) is similar, within our measurement errors, to that of the slower objects (1.0 ≤ s < 1.3) out to z ~ 0.8

    A Method for Analyzing Unreplicated Experiments Using Information on the Intraclass Correlation Coefficient

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    Many studies are performed on units that cannot be replicated; however, there is often an abundance of subsampling. By placing a reasonable upper bound on the intraclass correlation coefficient (ICC), it is possible to carry out classical tests of significance that have conservative levels of significance

    Knowledge of the Effects of Alcohol and Tobacco and Extent of Their Use by Utah State University Students

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    Student understanding and use of alcohol and tobacco at Utah State University was studied under the following areas: specific knowledge as it relates to smoking and health and drinking and health, student opinions and attitudes toward smoking and drinking, smoking and drinking experiences, the influence of certain factors on smoking and drinking status, and source and credibility of tobacco and alcohol information. Thirteen hundred seventy-eight students were sampled with the use of a questionnaire. It included 567 freshmen, 274 sophomores, 345 juniors, and 192 seniors. The sample covered each of the eight colleges at the University. It was found that the boys were better informed about tobacco and alcohol than the girls; however, student knowledge about the effects of tobacco and alcohol is very low. Most of the students were of the opinion that smoking and drinking are not worth the risk a person takes in terms of health. A large majority do not want their children to use tobacco or alcohol. Thirteen per cent of the students are regular smokers (smoke at least once a week), and 17 per cent drink regularly. Acceptance by their social group had the greatest influence on why students were smoking and drinking, Health implications, religious training, and parents\u27 objections were the factors influencing those who did not use tobacco and alcohol. The majority of the students indicated they received most of their information about tobacco and alcohol from health classes, from religious sources of information, and from parents or members of their family, in that order

    MegaPipe: the MegaCam image stacking pipeline at the Canadian Astronomical Data Centre

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    This paper describes the MegaPipe image processing pipeline at the Canadian Astronomical Data Centre. The pipeline combines multiple images from the MegaCam mosaic camera on CFHT and combines them into a single output image. MegaPipe takes as input detrended MegaCam images and does a careful astrometric and photometric calibration on them. The calibrated images are then resampled and combined into image stacks. The astrometric calibration of the output images is accurate to within 0.15 arcseconds relative to external reference frames and 0.04 arcseconds internally. The photometric calibration is good to within 0.03 magnitudes. The stacked images and catalogues derived from these images are available through the CADC website:Comment: Data available at http://www.cadc-ccda.hia-iha.nrc-cnrc.gc.ca/megapipe/index.htm

    Genetic heterogeneity in follicular lymphoma

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    The genetic underpinnings of follicular lymphoma (FL) are now better understood through sequencing efforts of the last decade. Epigenetic deregulation, particularly through mutations in chromatin-modifying enzymes, is recognised as a pivotal hallmark that occurs alongside the t(14;18) chromosomal translocation, together with mutations in genes that affect a number of secondary biological pathways including mTORC1, JAK-STAT, NF-kB signalling and immune evasion. In recent years, the functional relevance of these genetic aberrations has been independently deciphered. The protracted nature of FL has provided an excellent model to chart the heterogeneity and evolution of the genetic features of the lymphomas both temporally and spatially. These studies have pointed to the early and late genetic drivers of the disease and the existence of a putative reservoir population that is difficult to eradicate with conventional treatment and most likely contributes to the relapsing-remitting nature of FL. Additionally, these sequencing studies have identified similarities and distinct differences in the genetic profiles of FL compared to related histological entities. In this review, we aim to summarise the current state of our understanding of the genetic landscape and heterogeneity, its contribution to the spectrum of clinical phenotypes in FL and related entities and finally, the ongoing efforts to utilise biology to provide lines of sight to the clinic

    Female reproductive strategy predicts preferences for sexual dimorphism in male faces

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    The aim of the current studies was to test an assumption that variation in female preferences for sexually dimorphic male facial characteristics reflects strategic optimisation of investment in offspring. A negative relationship was predicted between ideal number of children and preferences for masculine male face shapes, as the benefits of securing paternal investment should outweigh the benefits of securing good genes as the costs of raising offspring increase. In Study 1 desired number of children and preferences for masculine face shapes were compared in a sample of female students. In study 2, the prediction was tested in a sample with a wider age profile while controlling for relationship status. Preferences for explicit partner characteristics were also assessed. The prediction was supported: women who desired a higher number of children preferred more feminine male face shapes and ranked cues to investment of parental care over cues to immunocompetence in a partner more highly than those who desired fewer children. Results indicate that female mate preferences vary with reproductive strategy and support assumptions that preferences for feminine male faces reflect preferences for “good dads”

    'Building Jobs’: Renewal SA’s Works Program at Playford Alive

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    YesThis report provides a detailed overview of Renewal SA’s Works Program implemented as part of Playford Alive, a large scale urban renewal project representing a partnership between Renewal SA, the City of Playford, the Department for Communities and Social Inclusion (DCSI), Housing SA and the local community. It documents evidence generated by semi‐structured interviews with project staff and participants of the program. Renewal SA’s Works Program at Playford Alive requires private contractors and service providers to deliver either work experience and longer term placements or training to a number of local unemployed people as a condition of being awarded the contract

    Observations of potential ultra high energy gamma-ray sources above 10(15) eV

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    The Haverah Park 50 m water-Cerenkov array has been used to examine a number of periodic sources for ultra high energy gamma-ray emission above 10 to the 15th power eV. The data, recorded between 1 Jan. 1979 and 31 Dec. 1984, feature a modest angular resolution of approx 3 deg with millisecond arrival time resolution post 1982. The sources investigated include the Crab pulsar, Her X-1, Au0115 + 63 and Geminga. All objects have been detected by workers in the TeV region, with varying degrees of confidence

    Own attractiveness and perceived relationship quality shape sensitivity in women’s memory for other men on the attractiveness dimension

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    Although recent work suggests that opposite-sex facial attractiveness is less salient in memory when individuals are in a committed romantic relationship, romantic relationship quality can vary over time. In light of this, we tested whether activating concerns about romantic relationship quality strengthens memory for attractive faces. Partnered women were exposed briefly to faces manipulated in shape cues to attractiveness before either being asked to think about a moment of emotional closeness or distance in their current relationship. We measured sensitivity in memory for faces as the extent to which they recognized correct versions of studied faces over versions of the same person altered to look either more or less-attractive than their original (i.e. studied) version. Contrary to predictions, high relationship quality strengthened hit rate for faces regardless of the sex or attractiveness of the face. In general, women’s memories were more sensitive to attractiveness in women, but were biased toward attractiveness in male faces, both when responding to unfamiliar faces and versions of familiar faces that were more attractive than the original male identity from the learning phase. However, findings varied according to self-rated attractiveness and a psychometric measure of the quality of their current relationship. Attractive women were more sensitive to attractiveness in men, while their less-attractive peers had a stronger bias to remember women as more-attractive and men as less-attractive than their original image respectively. Women in better-quality romantic relationships had stronger positive biases toward, and false memories for, attractive men. Our findings suggest a sophisticated pattern of sensitivity and bias in women’s memory for facial cues to quality that varies systematically according to factors that may alter the costs of female mating competition (‘market demand’) and relationship maintenance

    African perceptions of female attractiveness

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    Little is known about mate choice preferences outside Western, educated, industrialised, rich and democratic societies, even though these Western populations may be particularly unrepresentative of human populations. To our knowledge, this is the first study to test which facial cues contribute to African perceptions of African female attractiveness and also the first study to test the combined role of facial adiposity, skin colour (lightness, yellowness and redness), skin homogeneity and youthfulness in the facial attractiveness preferences of any population. Results show that youthfulness, skin colour, skin homogeneity and facial adiposity significantly and independently predict attractiveness in female African faces. Younger, thinner women with a lighter, yellower skin colour and a more homogenous skin tone are considered more attractive. These findings provide a more global perspective on human mate choice and point to a universal role for these four facial cues in female facial attractiveness.Publisher PDFPeer reviewe
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