1,762 research outputs found
Reply to Comment on ‘‘Experimental test of the Anderson–Mott transition model for excitation transport’’
It is argued that the critical electronic energy transfer EET concentrations observed in naphthalene2,4 are not accounted for by the Klafler and Fortner1,3,5 models of an Anderson transition. (AIP)Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70450/2/JCPSA6-73-2-1005-1.pd
Experimental test of the Anderson–Mott transition model for excitation transporta)
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69648/2/JCPSA6-70-6-3133-1.pd
Disruption of normal body axis formation after teratogen exposure
International audienceUrban transport plans in France (UTPs) aim to develop mobility for everyone and to find a balance between cars, public transport and other transport modes, this in order to favour sustainable mobility. In this article, the question of the utility derived from such policies is raised for the inhabitants of Nantes, which was designated the ‘European Green Capital’ in 2013. We analyse the capitalization of various effects of urban transport policies in housing values. Using a hedonic price model, we show that housing values in Nantes are significantly determined by improved accessibility to the city centre. We highlight contrasting effects of UTPs on housing values depending on the location of apartments and on the mode of public transport. Households also internalize air and noise pollution generated by transportation, but they attach only a low value to pollution exposure
Inhibition of Sonic hedgehog signaling in vivo results in craniofacial neural crest cell death
Background: Sonic hedgehog (Shh) is well known for its role in patterning tissues, including structures of the head. Haploinsufficiency for SHH in humans results in holoprosencephaly, a syndrome characterized by facial and forebrain abnormalities. Shh null mice have cyclopia and loss of branchial arch structures. It is unclear, however, whether these phenotypes arise solely from the early function of Shh in patterning midline structures, or whether Shh plays other roles in head development.
Results: To address the role of Shh after floorplate induction, we inhibited Shh signaling by injecting hybridoma cells that secrete a function-blocking anti-Shh antibody into the chick cranial mesenchyme. The antibody subsequently bound to Shh in the floorplate, notochord, and the pharyngeal endoderm. Perturbation of Shh signaling at this stage resulted in a significant reduction in head size after 1 day, loss of branchial arch structures after 2 days, and embryos with smaller heads after 7 days. Cell death was significantly increased in the neural tube and neural crest after 1 day, and neural crest cell death was not secondary to the loss of neural tube cells.
Conclusions: Reduction of Shh signaling after neural tube closure resulted in a transient decrease in neural tube cell proliferation and an extensive increase in cell death in the neural tube and neural crest, which in turn resulted in decreased head size. The phenotypes observed after reduction of Shh are similar to those observed after cranial neural crest ablation. Thus, our results demonstrate a role for Shh in coordinating the proliferation and survival of cells of the neural tube and cranial neural crest
Extremely narrow spectrum of GRB110920A: further evidence for localised, subphotospheric dissipation
Much evidence points towards that the photosphere in the relativistic outflow
in GRBs plays an important role in shaping the observed MeV spectrum. However,
it is unclear whether the spectrum is fully produced by the photosphere or
whether a substantial part of the spectrum is added by processes far above the
photosphere. Here we make a detailed study of the ray emission from
single pulse GRB110920A which has a spectrum that becomes extremely narrow
towards the end of the burst. We show that the emission can be interpreted as
Comptonisation of thermal photons by cold electrons in an unmagnetised outflow
at an optical depth of . The electrons receive their energy by a
local dissipation occurring close to the saturation radius. The main spectral
component of GRB110920A and its evolution is thus, in this interpretation,
fully explained by the emission from the photosphere including localised
dissipation at high optical depths.Comment: 14 pages, 11 figures, accepted to MNRA
Phase composition and transformations in magnetron-sputtered (Al,V)2O3 coatings
Coatings of (Al1-xVx)2O3, with x ranging from 0 to 1, were deposited by
pulsed DC reactive sputter deposition on Si(100) at a temperature of 550
{\deg}C. XRD showed three different crystal structures depending on V-metal
fraction in the coating: {\alpha}-V2O3 rhombohedral structure for 100 at.% V, a
defect spinel structure for the intermediate region, 63 - 42 at.% V. At lower
V-content, 18 and 7 at.%, a gamma-alumina-like solid solution was observed,
shifted to larger d-spacing compared to pure {\gamma}-Al2O3. The microstructure
changes from large columnar faceted grains for {\alpha}-V2O3 to smaller
equiaxed grains when lowering the vanadium content toward pure {\gamma}-Al2O3.
Annealing in air resulted in formation of V2O5 crystals on the surface of the
coating after annealing to 500 {\deg}C for 42 at.% V and 700 {\deg}C for 18
at.% V metal fraction respectively. The highest thermal stability was shown for
pure {\gamma}-Al2O3-coating, which transformed to {\alpha}-Al2O3 after
annealing to 1100{\deg} C. Highest hardness was observed for the Al-rich
oxides, ~24 GPa. The latter decreased with increasing V-content, larger than 7
at.% V metal fraction. The measured hardness after annealing in air decreased
in conjunction with the onset of further oxidation of the coatings
Birth size in the most recent pregnancy and maternal mortality in premenopausal breast cancer by tumor characteristics
The main aim of this study was to investigate possible associations between measures of offspring size at birth in the most recent pregnancy before premenopausal breast cancer diagnosis and the risks of maternal breast cancer mortality, taking tumor characteristics into account. We also aimed to investigate if these associations are modified by age at childbirth, time since childbirth, parity, and age at diagnosis. We followed 6,019 women from their date of premenopausal breast cancer (diagnosed from 1992 to 2008) until emigration, death or December 31st, 2009, whichever occurred first. We used Cox proportional hazard regression models, adjusted for parity, age at diagnosis, and education level, to estimate associations between women pregnancy, cancer characteristics and offspring birth characteristics, and mothers' mortality risk. In stratified analyses, mortality risks were estimated by tumor stage, ER or PR status. There was no association between offspring birth weight (HR = 1.00, 95 % CI 0.99-1.01, when used as a continuous variable), birth weight for gestational age or ponderal index, and premenopausal breast cancer mortality. Similarly, in analyses stratified by tumor stage, receptor status, and time difference between last pregnancy and date of diagnosis, we found no associations between birth size and breast cancer mortality. Our findings suggest that the hypothesis that "premenopausal breast cancer mortality is associated with offspring birth characteristics in the most recent pregnancy before the diagnosis" may not be valid. In addition, these associations are not modified by tumor characteristics. © 2014 Springer Science+Business Media New York
Universality and critical exponents of energy transport in binary crystals: 3B2u naphthalene
Exciton migration experiments on isotopically mixed naphthalene crystals reveal a universal behavior with reduced donor concentration, irrespective of temperature, acceptor species or acceptor concentration, giving a very wide scaling region, with critical exponents [gamma] = 2.1 +/- 0.22 and [beta] = 0.13 +/- 0.05, consistent with two-dimensional dynamic exciton percolation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24518/1/0000797.pd
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