72 research outputs found
Normal Type Ia supernovae from violent mergers of white dwarf binaries
One of the most important questions regarding the progenitor systems of Type
Ia supernovae (SNe Ia) is whether mergers of two white dwarfs can lead to
explosions that reproduce observations of normal events. Here we present a
fully three-dimensional simulation of a violent merger of two carbon-oxygen
white dwarfs with masses of and
combining very high resolution and exact initial conditions. A well-tested
combination of codes is used to study the system. We start with the dynamical
inspiral phase and follow the subsequent thermonuclear explosion under the
plausible assumption that a detonation forms in the process of merging. We then
perform detailed nucleosynthesis calculations and radiative transfer
simulations to predict synthetic observables from the homologously expanding
supernova ejecta. We find that synthetic color lightcurves of our merger, which
produces about of , show good
agreement with those observed for normal SNe Ia in all wave bands from U to K.
Line velocities in synthetic spectra around maximum light also agree well with
observations. We conclude, that violent mergers of massive white dwarfs can
closely resemble normal SNe Ia. Therefore, depending on the number of such
massive systems available these mergers may contribute at least a small
fraction to the observed population of normal SNe Ia.Comment: 6 pages, 4 figures, accepted for publication in ApJ
Winter wheat roots grow twice as deep as spring wheat roots, is this important for N uptake and N leaching losses?
Cropping systems comprising winter catch crops followed by spring wheat could reduce N leaching risks compared to traditional winter wheat systems in humid climates. We studied the soil mineral N (Ninorg) and root growth of winter- and spring wheat to 2.5 m depth during three years. Root depth of winter wheat (2.2 m) was twice that of spring wheat, and this was related to much lower amounts of Ninorg in the 1 to 2.5 m layer after winter wheat (81 kg Ninorg ha-1 less). When growing winter catch crops before spring wheat, N content in the 1 to 2.5 m layer after spring wheat was not different from that after winter wheat. The results suggest that by virtue of its deep rooting, winter wheat may not lead to high levels of leaching as it is often assumed in humid climates. Deep soil and root measurements (below 1 m) in this experiment were essential to answer the questions we posed
Overexpression and altered glycosylation of MUC1 in malignant mesothelioma
Current interest in the MUC1/EMA mucin relates to its role in malignancy, and its potential as a therapeutic target. MUC1/EMA expression has been observed in the majority of epithelioid mesotheliomas. However, little is known of the characteristics of MUC1/EMA in mesothelioma. Herein, we studied the cell surface and soluble expression of the MUC1/EMA glycoprotein, and determined the mRNA and genomic expression profiles in mesothelioma. We found that the anti-MUC1 antibody, E29, was the most diagnostically useful of seven antibody clones examined with a sensitivity of 84% (16 out of 19 cases) and no false positive results. MUC1 mRNA expression was significantly higher in mesothelioma samples than in benign mesothelial cells. No amplification of the MUC1 gene was observed by FISH. Seven of 9 mesothelioma samples expressed MUC1-secreted mRNA isoform in addition to the archetypal MUC1/transmembrane form. CA15.3 (soluble MUC1) levels were significantly higher in the serum of mesothelioma patients than in healthy controls but were not significantly different to levels in patients with benign asbestos-related disease. CA15-3 in effusions could differentiate malignant from benign effusions but were not specific for mesothelioma. Thus, as in other cancers, alterations in MUC1 biology occur in mesothelioma and these results suggest that specific MUC1 characteristics may be useful for mesothelioma diagnosis and should also be investigated as a potential therapeutic target
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Financial Advice and Gender: Wealthy Individual Investors in the UK
We examine how gender differences in investment risk tolerance, knowledge, confidence and portfolio cash allocations relate to the gender mix of investors and financial advisors among a sample of wealthy individuals in the UK. Our results demonstrate that gender effects are more nuanced than previously assumed. First, while even wealthy women consider themselves more conservative and allocate a higher proportion of their investable assets to cash than men, previous findings of lower investment knowledge and confidence do not extend to our sample. Second, having an advisor matters. Advised investors perceive themselves to have a higher risk tolerance and invest 10.6%-points more than self-directed investors. Finally, the investor-advisor gender combination matters, but only for female investors. Women with male advisors are more risk averse, feel less knowledgeable and less confident about their investment decisions. They also invest 11%-points less than women with female advisors. Indeed, female investors advised by women report the highest risk tolerance and make the lowest portfolio allocation to risk-free assets across the full sample, including men
Variations in investment advice provision: A study of financial advisors of millionaire investors
Vignette methodology is used to examine how the personal characteristics of investors and financial advisors contribute to portfolio recommendations, and the judgements
that advisors make about investment knowledge and control of prospective millionaire UK
clients. We find that advisors use investor characteristics to make recommendations broadly
in line with economic theory and regulatory requirements. However, women are judged less
knowledgeable and in control of their investments than equivalent men. They also receive
portfolio recommendations with slightly lower risk profiles. Portfolio recommendations vary
by advisor, with experienced advisors and those with wealthier clients recommending higher
risk portfolios. Unmeasured advisor variables also impact on judgements and recommendations. These findings have relevance to the wealth management industry and regulators, in
focusing attention on the conscious and unconscious influences on the judgements advisors
make about their clients
Financial advice, wealth and gender: risk tolerance, knowledge and confidence
We examine gender differences in investment risk tolerance, knowledge, confidence, and portfolio cash allocations among a sample of advised and self-directed wealthy individuals. Our results demonstrate that gender effects are more complicated than previously assumed. First, while even wealthy women consider themselves more conservative and hold more cash than men, previous findings of lower confidence and knowledge do not extend to our sample wealthy women. Second, having an advisor matters. Advised investors perceive themselves to have a higher risk tolerance and hold 15% points less cash than self-directed investors. Finally, the investor-advisor gender combination matters, but only for female investors. Women with male advisors are more risk averse, and feel less knowledgeable and less confident about investments. They also hold 11% more cash than women with female advisors. Indeed, female investors advised by women report the highest risk tolerance and make the lowest portfolio allocation to risk-free assets across the full sample, including men.<br
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