95 research outputs found
Measurements of electron-proton elastic cross sections for
We report on precision measurements of the elastic cross section for
electron-proton scattering performed in Hall C at Jefferson Lab. The
measurements were made at 28 unique kinematic settings covering a range in
momentum transfer of 0.4 5.5 . These measurements
represent a significant contribution to the world's cross section data set in
the range where a large discrepancy currently exists between the ratio of
electric to magnetic proton form factors extracted from previous cross section
measurements and that recently measured via polarization transfer in Hall A at
Jefferson Lab.Comment: 17 pages, 18 figures; text added, some figures replace
Nuclear transparency from quasielastic A(e,e'p) reactions uo to Q^2=8.1 (GeV/c)^2
The quasielastic (e,ep) reaction was studied on targets of
deuterium, carbon, and iron up to a value of momentum transfer of 8.1
(GeV/c). A nuclear transparency was determined by comparing the data to
calculations in the Plane-Wave Impulse Approximation. The dependence of the
nuclear transparency on and the mass number was investigated in a
search for the onset of the Color Transparency phenomenon. We find no evidence
for the onset of Color Transparency within our range of . A fit to the
world's nuclear transparency data reflects the energy dependence of the free
proton-nucleon cross section.Comment: 11 pages, 6 figure
Photon shot-noise limited transient absorption soft X-ray spectroscopy at the European XFEL
Femtosecond transient soft X-ray Absorption Spectroscopy (XAS) is a very
promising technique that can be employed at X-ray Free Electron Lasers (FELs)
to investigate out-of-equilibrium dynamics for material and energy research.
Here we present a dedicated setup for soft X-rays available at the Spectroscopy
& Coherent Scattering (SCS) instrument at the European X-ray Free Electron
Laser (EuXFEL). It consists of a beam-splitting off-axis zone plate (BOZ) used
in transmission to create three copies of the incoming beam, which are used to
measure the transmitted intensity through the excited and unexcited sample, as
well as to monitor the incoming intensity. Since these three intensity signals
are detected shot-by-shot and simultaneously, this setup allows normalized
shot-by-shot analysis of the transmission. For photon detection, the DSSC
imaging detector, which is capable of recording up to 800 images at 4.5 MHz
frame rate during the FEL burst, is employed and allows approaching the photon
shot-noise limit. We review the setup and its capabilities, as well as the
online and offline analysis tools provided to users.Comment: 11 figure
Eicosanoids in skin inflammation.
NoEicosanoids play an integral part in homeostatic mechanisms related to skin health and structural integrity. They also mediate inflammatory events developed in response to environmental factors, such as exposure to ultraviolet radiation, and inflammatory and allergic disorders, including psoriasis and atopic dermatitis. This review article discusses biochemical aspects related to cutaneous eicosanoid metabolism, the contribution of these potent autacoids to skin inflammation and related conditions, and considers the importance of nutritional supplementation with bioactives such as omega-3 and omega-6 polyunsaturated fatty acids and plant-derived antioxidants as means of addressing skin health issues.The Wellcome Trust and BBSRC-DRIN
Air pollution from traffic and cancer incidence: a Danish cohort study
<p>Abstract</p> <p>Background</p> <p>Vehicle engine exhaust includes ultrafine particles with a large surface area and containing absorbed polycyclic aromatic hydrocarbons, transition metals and other substances. Ultrafine particles and soluble chemicals can be transported from the airways to other organs, such as the liver, kidneys, and brain. Our aim was to investigate whether air pollution from traffic is associated with risk for other cancers than lung cancer.</p> <p>Methods</p> <p>We followed up 54,304 participants in the Danish Diet Cancer and Health cohort for 20 selected cancers in the Danish Cancer Registry, from enrolment in 1993-1997 until 2006, and traced their residential addresses from 1971 onwards in the Central Population Registry. We used modeled concentration of nitrogen oxides (NO<sub>x</sub>) and amount of traffic at the residence as indicators of traffic-related air pollution and used Cox models to estimate incidence rate ratios (IRRs) after adjustment for potential confounders.</p> <p>Results</p> <p>NO<sub>x </sub>at the residence was significantly associated with risks for cervical cancer (IRR, 2.45; 95% confidence interval [CI], 1.01;5.93, per 100 ÎŒg/m<sup>3 </sup>NO<sub>x</sub>) and brain cancer (IRR, 2.28; 95% CI, 1.25;4.19, per 100 ÎŒg/m<sup>3 </sup>NO<sub>x</sub>).</p> <p>Conclusions</p> <p>This hypothesis-generating study indicates that traffic-related air pollution might increase the risks for cervical and brain cancer, which should be tested in future studies.</p
ATHENA detector proposal - a totally hermetic electron nucleus apparatus proposed for IP6 at the Electron-Ion Collider
ATHENA has been designed as a general purpose detector capable of delivering the full scientific scope of the Electron-Ion Collider. Careful technology choices provide fine tracking and momentum resolution, high performance electromagnetic and hadronic calorimetry, hadron identification over a wide kinematic range, and near-complete hermeticity.This article describes the detector design and its expected performance in the most relevant physics channels. It includes an evaluation of detector technology choices, the technical challenges to realizing the detector and the R&D required to meet those challenges
ATHENA detector proposal â a totally hermetic electron nucleus apparatus proposed for IP6 at the Electron-Ion Collider
ATHENA has been designed as a general purpose detector capable of delivering the full scientific scope of the Electron-Ion Collider. Careful technology choices provide fine tracking and momentum resolution, high performance electromagnetic and hadronic calorimetry, hadron identification over a wide kinematic range, and near-complete hermeticity. This article describes the detector design and its expected performance in the most relevant physics channels. It includes an evaluation of detector technology choices, the technical challenges to realizing the detector and the R&D required to meet those challenges
Spatial Pattern and genetic structure of PPV-M in a delimited area of stone fruit orchards in southern France
International audienceThe spatial pattern and genetic structure of the Plum pox virus strain M have been studied in a delimited area of ca. 450 ha of stone fruit orchards. In this area, the Sharka disease spread undetected until its discovery in 2004. An exhaustive mapping of the diseased trees was performed using GIS technology in 2004 and 2005. Samples constituted by a pool of flowers or leaves were taken from each diseased tree. Analyses of the genetic structure of the virus populations have been initiated using Capillary Electrophoresis-Single Strand Conformation Polymorphism (CE-SSCP). Each haplotype detected by SSCP was further characterized by direct sequencing of the PCR products. The genetic diversity of PPV populations was low with one major haplotype representing 73% of the collected samples. Three other haplotypes from the 37 detected were found on more than 10 trees. Despite this low diversity, genetic variation had a clear spatial structure
Evaluation of three ornamentals Prunus as reservoirs of PPV
UMR BGPI Equipe 6International audienceThree ornamental Prunus (P. cerasifera âpissardiiâ, P. spinosa, P. triloba) were checked for their susceptibility to Plum pox virus when inoculated either by grafting or by aphid inoculation. If the species appeared as susceptible, the virus distribution throughout the plants was checked and used as an indicator to assess the possible role of these plants as PPV reservoirs for aphids. Two isolates of PPV-M, 2 isolates of PPV-D and a variant of PPV-D epidemic on peach trees were used to cover the range of PPV diversity found in France. The plants were checked by ELISA during the 3 vegetative periods following their inoculation. No systemic infection could be detected in P. pissardii or P. triloba during the 2 first years. Three P. pissardii plants inoculated by grafting were found infected the third year. On the contrary P. spinosa was found susceptible to every type of PPV isolates. The assessment of P. spinosa infected plants as PPV reservoirs was made by immunoprinting of the leaves the second year after inoculation. Only a few number of leaves were detected infected. Their distribution do not follow a regular patter
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