376 research outputs found
Determining the nuclear neutron distribution from Coherent Elastic neutrino-Nucleus Scattering: current results and future prospects
Coherent Elastic neutrino-Nucleus Scattering (CEνNS), a process recently measured for the first time at ORNL's Spallation Neutron Source, is directly sensitive to the weak form factor of the nucleus. The European Spallation Source (ESS), presently under construction, will generate the most intense pulsed neutrino flux suitable for the detection of CEνNS. In this paper we quantify its potential to determine the root mean square radius of the point-neutron distribution, for a variety of target nuclei and a suite of detectors. To put our results in context we also derive, for the first time, a constraint on this parameter from the analysis of the energy and timing data of the CsI detector at the COHERENT experiment
Exact positioning for OSEM reconstructions on the atlas depth-of-interaction small animal scanner
[Abstract] AMI Annual Conference 2002, October 23 - 27Publicad
Clinical and epidemiological characterization of a lymphogranuloma venereum outbreak in Madrid, Spain: co-circulation of two variants
AbstractThe lymphogranuloma venereum (LGV) outbreak described in the Netherlands in 2003, increased the interest in the genotyping of Chlamydia trachomatis. Although international surveillance programmes were implemented, these studies slowly decreased in the following years. Now data have revealed a new accumulation of LGV cases in those European countries with extended surveillance programmes. Between March 2009 and November 2011, a study was carried out to detect LGV cases in Madrid. The study was based on screening of C. trachomatis using commercial kits, followed by real-time pmpH-PCR discriminating LGV strains, and finally ompA gene was sequenced for phylogenetic reconstruction. Ninety-four LGV infections were identified. The number of cases increased from 10 to 30 and then to 54 during 2009–2011. Incidence of LGV was strongly associated with men who have sex with men; but in 2011, LGV cases were described in women and heterosexual men. Sixty-nine patients were also human immunodeficiency virus (HIV) positive, with detectable viral loads at the moment of LGV diagnosis, suggesting a high-risk of co-transmission. In fact, in four patients the diagnosis of HIV was simultaneous with LGV infection. The conventional treatment with doxycycline was prescribed in 75 patients, although in three patients the treatment failed. The sequencing of the ompA gene permitted identification of two independent transmission nodes. One constituted by 25 sequences identical to the L2b variant, and a second node including 37 sequences identical to L2. This epidemiological situation characterized by the co-circulation of two LGV variants has not been previously described, reinforcing the need for screening and genotyping of LGV strains
Effects of morphine self-administration on brain glucose metabolism in rats
Abstract of: AMI Annual Conference 2006, March 25-29Chronic exposure to opiates has been shown to influence neural activity in brain regions related to the rewarding process. It also induces neuroadaptations which lead to addiction. We have found in previous works that morphine self-administration produces neuroadaptative changes in brain areas of Fischer-344 rats. The aim of this study is to examine the effect of chronic self-administration of morphine on cerebral glucose metabolismPublicad
The stellar masses and specific star-formation rates of submillimetre galaxies
Establishing the stellar masses (M*), and hence specific star-formation rates
(sSFRs) of submillimetre galaxies (SMGs) is crucial for determining their role
in the cosmic galaxy/star formation. However, there is as yet no consensus over
the typical M* of SMGs. Specifically, even for the same set of SMGs, the
reported average M* have ranged over an order of magnitude, from ~5x10^10 Mo to
~5x10^11 Mo. Here we study how different methods of analysis can lead to such
widely varying results. We find that, contrary to recent claims in the
literature, potential contamination of IRAC 3-8 um photometry from hot dust
associated with an active nucleus is not the origin of the published
discrepancies in derived M*. Instead, we expose in detail how inferred M*
depends on assumptions made in the photometric fitting, and quantify the
individual and cumulative effects of different choices of initial mass
function, different brands of evolutionary synthesis models, and different
forms of assumed star-formation history. We review current observational
evidence for and against these alternatives as well as clues from the
hydrodynamical simulations, and conclude that, for the most justifiable choices
of these model inputs, the average M* of SMGs is ~2x10^11 Mo. We also confirm
that this number is perfectly reasonable in the light of the latest
measurements of their dynamical masses, and the evolving M* function of the
overall galaxy population. M* of this order imply that the average sSFR of SMGs
is comparable to that of other star-forming galaxies at z>2, at 2-3 Gyr^-1.
This supports the view that, while rare outliers may be found at any M*, most
SMGs simply form the top end of the main-sequence of star-forming galaxies at
these redshifts. Conversely, this argues strongly against the viewpoint that
SMGs are extreme pathological objects, of little relevance in the cosmic
history of star-formation.Comment: Accepted to A&A. 13 pages, 5 figures, 3 tables. Main changes: 1)
investigation that the main-sequence does not change the location as much as
SMGs when changing SFHs; 2) a new table added with all stellar mass estimates
for individual SMGs (machine-readable version in the source file). V3:
missing references adde
Biochar reduces the efficiency of nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) mitigating N2O emissions
Among strategies suggested to decrease agricultural soil N2O losses, the use of nitrification inhibitors such as DMPP (3,4-dimethylpyrazole phosphate) has been proposed. However, the efficiency of DMPP might be affected by soil amendments, such as biochar, which has been shown to reduce N2O emissions. This study evaluated the synergic effect of a woody biochar applied with DMPP on soil N2O emissions. A incubation study was conducted with a silt loam soil and a biochar obtained from Pinus taeda at 500 degrees C. Two biochar rates (0 and 2% (w/w)) and three different nitrogen treatments (unfertilized, fertilized and fertilized + DMPP) were assayed under two contrasting soil water content levels (40% and 80% of water filled pore space (WFPS)) over a 163 day incubation period. Results showed that DMPP reduced N2O emissions by reducing ammonia-oxidizing bacteria (AOB) populations and promoting the last step of denitrification (measured by the ratio nosZI + nosZII/nirS + nirK genes). Biochar mitigated N2O emissions only at 40% WFPS due to a reduction in AOB population. However, when DMPP was applied to the biochar amended soil, a counteracting effect was observed, since the N2O mitigation induced by DMPP was lower than in control soil, demonstrating that this biochar diminishes the efficiency of the DMPP both at low and high soil water contents.This work was funded by the Spanish Government (AGL2015-64582-C3-2-R MINECO/FEDER), by the Basque Government (IT-932-16) and by the European Union (FACCE-CSA no 276610/MIT04-DESIGN-UPVASC, FACCE-CSA no 2814ERA01A and 2814ERA02A). This work is also supported by the USDA/NIFA Interagency Climate Change Grant Proposal number 2014-02114 [Project number 6657-12130-002-08I, Accession number 1003011] under the Multi-Partner Call on Agricultural Greenhouse Gas Research of the FACCE-Joint Program Initiative. Any opinions, findings, or recommendation expressed in this publication are those of the authors and do not necessarily reflect the view of the USDA. MLC was supported by a Ramon y Cajal contract from the Spanish Ministry of Economy and Competitiveness and thanks Fundacion Seneca for financing the project 19281/PI/14
The starburst-AGN connection in the merger galaxy Mrk 938: an infrared and X-ray view
Mrk938 is a luminous infrared galaxy in the local Universe believed to be the
remnant of a galaxy merger. It shows a Seyfert 2 nucleus and intense star
formation according to optical spectroscopic observations. We have studied this
galaxy using new Herschel far-IR imaging data in addition to archival X-ray,
UV, optical, near-IR and mid-IR data. Mid- and far-IR data are crucial to
characterise the starburst contribution, allowing us to shed new light on its
nature and to study the coexistence of AGN and starburst activity in the local
Universe. The decomposition of the mid-IR Spitzer spectrum shows that the AGN
bolometric contribution to the mid-IR and total infrared luminosity is small
(Lbol(AGN)/LIR~0.02), which agrees with previous estimations. We have
characterised the physical nature of its strong infrared emission and
constrained it to a relatively compact emitting region of <2kpc. It is in this
obscured region where most of the current star formation activity is taking
place as expected for LIRGs. We have used Herschel imaging data for the first
time to constrain the cold dust emission with unprecedented accuracy. We have
fitted the integrated far-IR spectral energy distribution and derived the
properties of the dust, obtaining a dust mass of 3x10^7Msun. The far-IR is
dominated by emission at 35K, consistent with dust heated by the on-going star
formation activity.Comment: 12 pages, 6 figures, 4 tables, accepted for publication in MNRA
High intensity neutrino oscillation facilities in Europe
The EUROnu project has studied three possible options for future, high intensity neutrino oscillation facilities in Europe. The first is a Super Beam, in which the neutrinos come from the decay of pions created by bombarding targets with a 4 MW proton beam from the CERN High Power Superconducting Proton Linac. The far detector for this facility is the 500 kt MEMPHYS water Cherenkov, located in the Fréjus tunnel. The second facility is the Neutrino Factory, in which the neutrinos come from the decay of μ+ and μ− beams in a storage ring. The far detector in this case is a 100 kt magnetized iron neutrino detector at a baseline of 2000 km. The third option is a Beta Beam, in which the neutrinos come from the decay of beta emitting isotopes, in particular He6 and Ne18, also stored in a ring. The far detector is also the MEMPHYS detector in the Fréjus tunnel. EUROnu has undertaken conceptual designs of these facilities and studied the performance of the detectors. Based on this, it has determined the physics reach of each facility, in particular for the measurement of CP violation in the lepton sector, and estimated the cost of construction. These have demonstrated that the best facility to build is the Neutrino Factory. However, if a powerful proton driver is constructed for another purpose or if the MEMPHYS detector is built for astroparticle physics, the Super Beam also becomes very attractive
The Imaging Magnetograph eXperiment (IMaX) for the Sunrise balloon-borne solar observatory
The Imaging Magnetograph eXperiment (IMaX) is a spectropolarimeter built by
four institutions in Spain that flew on board the Sunrise balloon-borne
telesocope in June 2009 for almost six days over the Arctic Circle. As a
polarimeter IMaX uses fast polarization modulation (based on the use of two
liquid crystal retarders), real-time image accumulation, and dual beam
polarimetry to reach polarization sensitivities of 0.1%. As a spectrograph, the
instrument uses a LiNbO3 etalon in double pass and a narrow band pre-filter to
achieve a spectral resolution of 85 mAA. IMaX uses the high Zeeman sensitive
line of Fe I at 5250.2 AA and observes all four Stokes parameters at various
points inside the spectral line. This allows vector magnetograms, Dopplergrams,
and intensity frames to be produced that, after reconstruction, reach spatial
resolutions in the 0.15-0.18 arcsec range over a 50x50 arcsec FOV. Time
cadences vary between ten and 33 seconds, although the shortest one only
includes longitudinal polarimetry. The spectral line is sampled in various ways
depending on the applied observing mode, from just two points inside the line
to 11 of them. All observing modes include one extra wavelength point in the
nearby continuum. Gauss equivalent sensitivities are four Gauss for
longitudinal fields and 80 Gauss for transverse fields per wavelength sample.
The LOS velocities are estimated with statistical errors of the order of 5-40
m/s. The design, calibration and integration phases of the instrument, together
with the implemented data reduction scheme are described in some detail.Comment: 17 figure
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