906 research outputs found
Îą-sinucleĂna, gotas lipĂdicas y un interactoma sin resolver
La Îą- sinucleĂna (Îą- sin) es una proteĂna citosĂłlica pequeĂąa, cuya agregaciĂłn y fibrilaciĂłn estĂĄn
estrechamente asociadas a un grupo de patologĂas degenerativas llamadas sinucleinopatĂas.
Diferentes estudios han demostrado que esta proteĂna posee una alta afinidad de uniĂłn a
lĂpidos, y a su vez se ha propuesto que actuarĂa como moduladora del metabolismo lipĂdico.Fil: Alza, N..
Consejo Nacional de Investigaciones CientĂficas y TĂŠcnicasFil: Conde, M..
Consejo Nacional de Investigaciones CientĂficas y TĂŠcnicasFil: Scodelaro Bilbao, P..
Consejo Nacional de Investigaciones CientĂficas y TĂŠcnicasFil: GonzĂĄlez Pardo, M..
Consejo Nacional de Investigaciones CientĂficas y TĂŠcnicasFil: Salvador, G..
Consejo Nacional de Investigaciones CientĂficas y TĂŠcnica
The biogeochemical structure of Southern Ocean mesoscale eddies
Mesoscale eddies play a key role in modulating physical and biogeochemical properties across the global ocean. They also play a central role in crossâfrontal transport of heat, freshwater, and carbon, especially in the Southern Ocean. However, the role that eddies play in the biogeochemical cycles is not yet well constrained, partly due to a lack of observations below the surface. Here, we use hydrographic data from two voyages, conducted in the austral summer and autumn, to document the vertical biogeochemical structure of two mesoscale cyclonic eddies and quantify the role of these eddies in the meridional transport of nutrients across the Subantarctic Front. Our study demonstrates that the nutrient distribution is largely driven by eddy dynamics, yielding identical eddy structure below the mixed layer in both seasons. This result allowed us to relate nutrient content to dynamic height and estimate the average transport by eddies across the Subantarctic Front. We found that relative to Subantarctic Zone waters, longâlived coldâcore eddies carry nitrate anomalies of 1.6Âą0.2Ă1010 moles and silicate anomalies of â5.5Âą0.7Ă1010 moles across the fronts each year. This crossâfrontal transport of nutrients has negligible impact on Subantarctic Zone productivity; however, it has potential to modify the nutrient content of mode waters that are exported from the Southern Ocean to lower latitudes
Air-sea CO2 fluxes in the Atlantic as measured during the FICARAM cruises
A total of fourteen hydrographic cruises spanning from 2000 to 2008 were conducted
during the spring and autumn seasons between Spain and the Southern Ocean, under
the framework of the Spanish research project FICARAM. The performed underway measurements are processed and analysed to describe the meridional air-sea CO2
fluxes (F CO2) along the Atlantic Ocean. The data was organised into different biogeochemical
oceanographic provinces, according mainly to the thermohaline characteristics.
The obtained spatial and temporal distributions of F CO2 follow the generally expected
patterns and annual trends. The Subtropical regions in both hemispheres alternated the CO2 source and sink nature from autumn to spring, respectively. On the other
hand, Tropical waters and the Patagonian Sea clearly behaved as sinks of atmospheric
CO2 like the waters of the Drake Passage during autumn. The obtained results during
the cruises also revealed significant long-term trends, such as the warming of equatorial
waters (0.11Âą0.03 Cyrâ1) and the decrease of surface salinity (â0.16Âą0.01 yrâ1)
in tropical waters caused by the influence of the Amazon River plume. This reduction
in surface salinity appears to have a direct influence over the CO2 storage rates, fostering
the uptake capacity of atmospheric CO2 (â0.09Âą0.03 molmâ2 yrâ1). An analysis
of the biogeochemical forcing on the CO2 fugacity (fCO2) variability performed from
an empirical algorithm highlighted the major role of the Amazon River input in the tropical North Atlantic fluxes. In addition, it has provided a quantitative measure of the
importance of the thermodynamic control of F CO2 at temperate latitudes
Search for the Flavor-Changing Neutral Current Decay with the HERA-B Detector
We report on a search for the flavor-changing neutral current decay using events recorded with a dimuon trigger in
interactions of 920 GeV protons with nuclei by the HERA-B experiment. We find
no evidence for such decays and set a 90% confidence level upper limit on the
branching fraction .Comment: 17 pages, 4 figures (of which 1 double), paper to be submitted to
Physics Letters
Open and Hidden Charm Production in 920 GeV Proton-Nucleus Collisions
The HERA-B collaboration has studied the production of charmonium and open
charm states in collisions of 920 GeV protons with wire targets of different
materials. The acceptance of the HERA-B spectrometer covers negative values of
xF up to xF=-0.3 and a broad range in transverse momentum from 0.0 to 4.8
GeV/c. The studies presented in this paper include J/psi differential
distributions and the suppression of J/psi production in nuclear media.
Furthermore, production cross sections and cross section ratios for open charm
mesons are discussed.Comment: 5 pages, 9 figures, to be published in the proceedings of the 6th
International Conference on Hyperons, Charm & Beauty Hadrons (BEACH04),
Chicago, IL, June 27 - July 3, 200
Measurement of the J/Psi Production Cross Section in 920 GeV/c Fixed-Target Proton-Nucleus Interactions
The mid-rapidity (dsigma_(pN)/dy at y=0) and total sigma_(pN) production
cross sections of J/Psi mesons are measured in proton-nucleus interactions.
Data collected by the HERA-B experiment in interactions of 920 GeV/c protons
with carbon, titanium and tungsten targets are used for this analysis. The
J/Psi mesons are reconstructed by their decay into lepton pairs. The total
production cross section obtained is sigma_(pN)(J/Psi) = 663 +- 74 +- 46
nb/nucleon. In addition, our result is compared with previous measurements
Performance Evaluation of the Dual Ring MAMMI breast PET
[Otros] MAMMI is a dedicated breast positron emission tomograph (PET) based on monolythic LYSO crystals, with a transaxial field of view (FOV) of 170 mm. It has been upgraded by adding a second ring of detectors that extends the axial FOV from 40 mm to 94.4 mm, in order to improve its sensitivity and reduce the acquisition time. In this work we present the performance evaluation of the dual ring MAMMI breast PET and a discussion about the contribution of the addition of a second ring of detectors, the compensation of the detector blur and the increase of the scintillator thickness. Experimental measurements suggested on NEMA NU 4-2008 and NEMA NU 2-2007 have been conveniently adapted to the dimensions of the MAMMI. The addition of the second ring of detectors leads to a rise of the sensitivity from 1.8% to 3.6%. The spatial resolution at one-fourth of the axial FOV (1.5 mm axial, 1.6 mm tangential, 1.7 mm radial) is slightly better than that measured at the axial center (1.9 mm axial, 1.8 mm tangential and radial), because of the 14 mm gap in between detection rings. The results obtained after the evaluation reflect a substantial performance improvement, specially in the absolute sensitivity, because of the changes introduced in the MAMMI PET.This work was supported in part bythe Spanish Plan Nacional de Investigacion CientĂfica, Desarrollo e InnovaciĂłn Tecnologica (I+D+I) under Grant No. FIS2010-21216-CO2-01 and Valencian Local Government under Grants PROMETEOII/2013/010 and ISIC 2011/013Soriano, A.; SĂĄnchez, F.; Carrilero, V.; Pardo, A.; Vidal San Sebastian, LF.; Vazquez, C.; Barbera, J.... (2013). Performance Evaluation of the Dual Ring MAMMI breast PET. IEEE. 1-4. https://doi.org/10.1109/NSSMIC.2013.6829103S1
Performance and Operation of the CMS Electromagnetic Calorimeter
The operation and general performance of the CMS electromagnetic calorimeter
using cosmic-ray muons are described. These muons were recorded after the
closure of the CMS detector in late 2008. The calorimeter is made of lead
tungstate crystals and the overall status of the 75848 channels corresponding
to the barrel and endcap detectors is reported. The stability of crucial
operational parameters, such as high voltage, temperature and electronic noise,
is summarised and the performance of the light monitoring system is presented
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