720 research outputs found
Discovery of new TeV supernova remnant shells in the Galactic plane with H.E.S.S
Supernova remnants (SNRs) are prime candidates for efficient particle
acceleration up to the knee in the cosmic ray particle spectrum. In this work
we present a new method for a systematic search for new TeV-emitting SNR shells
in 2864 hours of H.E.S.S. phase I data used for the H.E.S.S. Galactic Plane
Survey. This new method, which correctly identifies the known shell
morphologies of the TeV SNRs covered by the survey, HESS J1731-347, RX
1713.7-3946, RCW 86, and Vela Junior, reveals also the existence of three new
SNR candidates. All three candidates were extensively studied regarding their
morphological, spectral, and multi-wavelength (MWL) properties. HESS J1534-571
was associated with the radio SNR candidate G323.7-1.0, and thus is classified
as an SNR. HESS J1912+101 and HESS J1614-518, on the other hand, do not have
radio or X-ray counterparts that would permit to identify them firmly as SNRs,
and therefore they remain SNR candidates, discovered first at TeV energies as
such. Further MWL follow up observations are needed to confirm that these newly
discovered SNR candidates are indeed SNRs
The Impact of New Polarization Data from Bonn, Mainz and Jefferson Laboratory on Multipoles
New data on pion-photoproduction off the proton have been included in the
partial wave analyses Bonn-Gatchina and SAID and in the dynamical
coupled-channel approach J\"ulich-Bonn. All reproduce the recent new data well:
the double polarization data for E, G, H, P and T in
from ELSA, the beam asymmetry for and
from Jefferson Laboratory, and the precise new differential cross section and
beam asymmetry data for from MAMI. The new fit
results for the multipoles are compared with predictions not taking into
account the new data. The mutual agreement is improved considerably but still
far from being perfect
Delayed administration of a matrix metalloproteinase inhibitor limits progressive brain injury after hypoxia-ischemia in the neonatal rat
<p>Abstract</p> <p>Background</p> <p>Hypoxia-ischemia (H-I) can produce widespread neurodegeneration and deep cerebral white matter injury in the neonate. Resident microglia and invading leukocytes promote lesion progression by releasing reactive oxygen species, proteases and other pro-inflammatory mediators. After injury, expression of the gelatin-degrading matrix metalloproteinases (MMPs), MMP-2 and MMP-9, are thought to result in the proteolysis of extracellular matrix (ECM), activation of cytokines/chemokines, and the loss of vascular integrity. Thus, therapies targeting ECM degradation and progressive neuroinflammation may be beneficial in reducing H-I – induced neuropathy. Minocycline has MMP-inhibitory properties and is both anti-inflammatory and neuroprotective. AG3340 (prinomastat) is an MMP inhibitor with high selectivity for the gelatinases. The purpose of this study was to determine whether these compounds could limit H-I – induced injury when administered at a delayed time point.</p> <p>Methods</p> <p>Sprague-Dawley rats were exposed to H-I at postnatal day 7 (P7), consisting of unilateral carotid artery ligation followed by 90 min exposure to 8% O<sub>2</sub>. Minocycline, AG3340, or vehicle were administered once daily for 6 days, beginning 24 hours after insult. Animals were sacrificed at P14 for neurohistological assessments. Immunohistochemistry was performed to determine the degree of reactive astrogliosis and immune cell activation/recruitment. Neural injury was detected using the Fluoro-Jade stain, a marker that identifies degenerating cells.</p> <p>Results</p> <p>CD11b and glial fibrillary acidic protein (GFAP) immunopositive cells increased in ipsilateral cortex after treatment with vehicle alone, demonstrating microglia/macrophage recruitment and reactive astrogliosis, respectively. Fluoro-Jade staining was markedly increased throughout the fronto-parietal cortex, striatum and hippocampus. Treatment with minocycline or AG3340 inhibited microglia/macrophage recruitment, attenuated astrogliosis and reduced Fluoro-Jade staining when compared to vehicle alone.</p> <p>Conclusion</p> <p>The selective gelatinase inhibitor AG3340 showed equal efficacy in reducing neural injury and dampening neuroinflammation when compared to the anti-inflammatory compound minocycline. Thus, MMP-2 and MMP-9 may be viable therapeutic targets to treat neonatal brain injury.</p
Design and implementation of a low-cost mechatronic shoe for biomechanical analysis of the human locomotion
In this paper the development of a low-cost and easy wearable mechatronic system for the measurement of ground reaction forces (GRF) for the biomechanical analysis of the human locomotion is presented. The system consists of an insole, a conditioning device for the signals produced by the sensors applied to the insole and a data acquisition system connected to a USB portable storage. The sensors applied to the insole can measure the reaction forces in the horizontal and vertical directions during locomotion. The prototype was validated by comparing the data from the sensors with the values obtained using a force platform
Randomized Trial of a Broad Preventive Intervention for Mexican American Adolescents
Objective—This randomized trial of a family-focused preventive intervention for Mexican American (MA) adolescents evaluated intervention effects on adolescent substance use, internalizing and externalizing symptoms, and school discipline and grade records in 8th grade, one year after completion of the intervention. The study also examined hypothesized mediators and moderators of intervention effects. Method—Stratified by language of program delivery (English vs. Spanish), the trial included a sample of 516 MA adolescents (50.8% female; M =12.3 years, SD=.54) and at least one caregiver that were randomized to receive a low dosage control group workshop or the 9-week group intervention that included parenting, adolescent coping, and conjoint family sessions. Results—Positive program effects were found on all five outcomes at one-year posttest, but varied depending on whether adolescents, parents, or teachers reported on the outcome. Intervention effects were mediated by posttest changes in effective parenting, adolescent coping efficacy, adolescent school engagement, and family cohesion. The majority of direct and mediated effects were moderated by language, with a larger number of significant effects for families that participated in Spanish. Intervention effects also were moderated by baseline levels of mediators and outcomes, with the majority showing stronger effects for families with poorer functioning at baseline. Conclusion—Findings support the efficacy of the intervention to decrease multiple problem outcomes for MA adolescents, but also demonstrate differential effects for parents and adolescents receiving the intervention in Spanish vs. English, and depending on their baseline levels of functioning
Experimental constraints on the -nucleus real potential
In a search for mesic states, the production of -mesons in
coincidence with forward going protons has been studied in photon induced
reactions on C for incident photon energies of 1250 - 3100 MeV. The
pairs from decays of bound or quasi-free -mesons have
been measured with the CBELSA/TAPS detector system in coincidence with protons
registered in the MiniTAPS forward array. Structures in the total energy
distribution of the pairs, which would indicate the population
and decay of bound B states, are not observed. The
cross section of 0.3 nb/MeV/sr observed in the bound state energy regime
between -100 and 0 MeV may be accounted for by yield leaking into the bound
state regime because of the large in-medium width of the -meson. A
comparison of the measured total energy distribution with calculations suggests
the real part of the B potential to be small and only
weakly attractive with 35(stat) 20(syst) MeV
in contrast to some theoretical predictions of attractive potentials with a
depth of 100 - 150 MeV.Comment: 13 pages, 8 figure
First measurement of the helicity asymmetry for in the resonance region
The first measurement of the helicity dependence of the photoproduction cross
section of single neutral pions off protons is reported for photon energies
from 600 to 2300\,MeV, covering nearly the full solid angle. The data are
compared to predictions from the SAID, MAID, and BnGa partial wave analyses.
Strikingly large differences between data and predictions are observed which
are traced to differences in the helicity amplitudes of well known and
established resonances. Precise values for the helicity amplitudes of several
resonances are reported
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