4,920 research outputs found
Open-beauty production in Pb collisions at =5 TeV: effect of the gluon nuclear densities
We present our results on open beauty production in proton-nucleus collisions
for the recent LHC Pb run at =5 TeV. We have analysed the
effect of the modification of the gluon PDFs in nucleus at the level of the
nuclear modification factor. Because of the absence of measurement in
collisions at the same energy, we also propose the study of the
forward-to-backward yield ratio in which the unknown proton-proton yield
cancel. Our results are compared with the data obtained by LHCb collaboration
and show a good agreement.Comment: 6 pages, 3 figures, Proceedings IS2013 submitted to Nuclear Physics
Z0 Boson Measurement with the ALICE Central Barrel in pp collisions at 14 TeV
The possibility to detect the Z0 in the ALICE central barrel is studied via
the electronic decay channel Z0->e+e-. The signal and the background are
simulated with the leading order event generator PYTHIA 6. The total
cross-sections are taken from NLO calculations. Based on test beam data, the
electron identification performance of the Transition Radiation Detector is
extrapolated to high momenta. The expected yields for minimum-bias pp
collisions at 14 TeV are presented. An isolation cut on the single electron,
together with a minimum transverse momentum cut, allows to obtain a clear
signal. The expected background is of the order of 1 % with the main
contribution coming from misidentified pions from jets.Comment: 4 pages, 3 figures, QM2008 proceeding
D meson nuclear modification factors in Pb-Pb collisions at {\surd}sNN = 2.76 TeV, measured with the ALICE detector
The ALICE experiment has measured the D meson production in pp and Pb-Pb
collisions at the LHC at {\surd}s = 7 and 2.76 TeV and {\surd}sNN = 2.76 TeV
respectively, via the exclusive reconstruction of hadronic decay channels. The
analyses of the D0{\to}K-pi+ and D+{\to}K-pi+pi+ channels will be described and
the preliminary results for the D0 and D+ nuclear modification factor will be
presented.Comment: Proceedings of Quark Matter 2011 conference. 4 pages, 4 figures. The
slides of the talk can be found at the link:
http://indico.cern.ch/materialDisplay.py?contribId=591&sessionId=53&materialId=slides&confId=3024
Effects of salinity and B excess on the growth, photosynthesis, water relation and mineral composition of laurustinus grown in greenhouse
Trabajo presentado en el XXVIII International Horticultural Congress on Science and Horticulture for People (IHC2010): International Symposium on Greenhouse 2010 and Soilless Cultivation, celebrado en Lisboa, Portugal, del 22 al 27 de agosto de 2010A greenhouse study was conducted to determine the interactive effects of NaCl
salinity and boron on the growth, plant water status, gas exchange, chlorophyll
fluorescence and concentrations of sodium (Na), chloride (Cl) and boron (B) in
laurustinus (Viburnum tinus L.). Potted plants were grown in a factorial
combination of salinity (2 and 6 dS m-1) and boron (1 and 6 mg L-1). Plant dry
weight (DW) decreased with salinity and B excess, particularly as a result of the
former. The salinity × B interaction on the plant DW was not significant (additive
effects). Salinity increased Na and Cl concentrations in leaf (20 and 35 mg g-1 DW,
respectively) resulting in foliar injury. The application of 6 mg L-1 of B (B toxicity or
B excess) produced injury symptoms in old leaves (leaf tip and edge burn). Salinity
and B toxicity led to leaves dropping, especially the former. B toxicity led to higher B
concentrations in insured leaves (1385 mg kg-1 DW) and salinity reduced it to 425 (B
x NaCl antagonistic effect). Boron excess did no alter Na and Cl concentrations in
leaf. Salinity decreased stomatal conductance (gs) as a regulatory mechanism against
osmotic stress, which resulted in a dropping photosynthesis (Pn). Leaf water
parameters were only affected by salinity, which enhanced a process of osmotic
adjustment and improving the plant water status. Salt-stressed plants showed an
adaptive response to salinity, which decreased gs, Pn and quantum yield of
photosystem II (éPSII), and dissipated the excess radiant energy as heat (increased
non-photochemical quenching [NPQ]). The combination of salinity and B excess
maintained éPSII and decreased the effectiveness of stomatal regulation, NPQ and
Pn. This caused the lowest plant DW and suggests disorders in electron transport
(photorespiration). Our findings suggest that: (1) laurustinus is a B excess sensitive
species, (2) salinity reduced the accumulation of B in leaves of the B excess stressed
plants but was not enough to prevent injuries in PSII, and (3) B excess or/and
salinity provide plants of poor commercial quality.This research was supported by CICYT projects (CICYT AGL2008-05258-CO2-
1-AGR and CICYT AGL2008-05258-CO2-2-AGR), SENECA project (08669/PI/08) and
by the ConsejerÃa de Agricultura y Agua de la Región de Murcia, program (UPCTCEBAS-
IMIDA 2008).Peer Reviewe
Efficient nickel and copper-based catalysts supported on modified graphite materials for the hydrogen production from formic acid decomposition
Ni, Cu and Ni-Cu catalysts supported on high surface area graphite were synthesized by incipient wet impregnation. Also, the effect of doping the graphite support with alkali oxides (Li, Na and K) was studied. The catalysts were tested in the formic acid decomposition reaction to produce hydrogen. The bimetallic Ni-Cu catalyst doped with K showed the best catalytic performance with 100% conversion of formic acid at 130 °C and a 95% of selectivity to hydrogen. The turnover frequency (TOF) of the catalysts follows the order: Ni-Cu/K > NiCu/Na > Ni-Cu > Ni-Cu/Li. While the order for the apparent activation energy values is: Ni-Cu > Ni-Cu/Li > Ni-Cu/Na > Ni-Cu/K. The mechanism of the reaction is approached by programmed temperature surface reaction (TPSR) experiments and attenuated total reflectance (ATR). The greater catalytic activity of the Ni-Cu catalyst doped with potassium is ascribed to the lower stability of the formate, bicarbonate and carbonate species on its surface.Fil: Faroldi, Betina MarÃa Cecilia. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y PetroquÃmica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y PetroquÃmica "Ing. José Miguel Parera"; Argentina. Consejo Superior de Investigaciones CientÃficas. Instituto de Catálisis y PetroleoquÃmica; EspañaFil: Conesa, J. M.. Consejo Superior de Investigaciones CientÃficas. Instituto de Catálisis y PetroleoquÃmica; EspañaFil: Guerrero Ruiz, A.. Universidad Nacional de Educacion A Distancia. Facultad de Ciencias.; EspañaFil: RodrÃguez Ramos, I.. Consejo Superior de Investigaciones CientÃficas. Instituto de Catálisis y PetroleoquÃmica; Españ
Plastia sustitutiva del LCA con tendones de la pata de ganso cuadruples
Se han estudiado retrospectivamente 44 casos de pacientes a los que se les realizó por vÃa artrocóspica una plastia sustitutiva intraticular de reconstrucción del LCA, con tendones de Semitendinoso y Recto Interno antólogos, en 4 fascÃculos. La edad media de los pacientes fue de 25 años. Los resultados a corto plazo (2 años) obtenidos con KT-1000 a 30 Ib han sido excelente-bueno en 40 casos y aceptable en 4 casos. Cuatro casos referÃan sensación de inestabilidad. Los test de Lachman y PÃvot-Shift fueron positivos en 3 casos. Con el test de Lysholm se obtuvo resultado excelente-bueno en 36 casos, regular en 6 y malo en 2 casos. Este tipo de plastia presenta una baja morbilidad de la zona dadora del injerto, comparativamente con la plastia HTH patelar antóloga, y sin alteración del aparato extensor.A retrospective study of 44 patients, who underwent an arthroscopically assisted ACL (anterior cruciata ligament) reconstruction with quadrupled semitendinosus/gracilis tendon autografts was performed. The mean age was 25 years. Short term outcomes of knee stability (2 years follow-up) with KT-1000 arthrometer at 30 pounds were excellent or good in 40 cases and acceptable in 4. Pain or joint swelling were not found. Instability complaints were found in 4 cases. Lachman and Pivot-shift were found positive in 3 cases. Lysholm questionnaire scores were excellent or good in 36 cases, fair in 6 cases and per in two cases, the donor site morbidity associated with hamstring harvest seems to be minimal compared with bonepatellar tendon-bone autograft without impairment of the extensor mechanism
Spatial Bayesian Modeling Applied to the Surveys of Xylella fastidiosa in Alicante (Spain) and Apulia (Italy)
The plant-pathogenic bacterium Xylella fastidiosa was first reported in Europe in 2013, in the province of Lecce, Italy, where extensive areas were affected by the olive quick decline syndrome, caused by the subsp. pauca. In Alicante, Spain, almond leaf scorch, caused by X. fastidiosa subsp. multiplex, was detected in 2017. The effects of climatic and spatial factors on the geographic distribution of X. fastidiosa in these two infested regions in Europe were studied. The presence/absence data of X. fastidiosa in the official surveys were analyzed using Bayesian hierarchical models through the integrated nested Laplace approximation (INLA) methodology. Climatic covariates were obtained from the WorldClim v.2 database. A categorical variable was also included according to Purcell’s minimum winter temperature thresholds for the risk of occurrence of Pierce’s disease of grapevine, caused by X. fastidiosa subsp. fastidiosa. In Alicante, data were presented aggregated on a 1 km grid (lattice data), where the spatial effect was included in the model through a conditional autoregressive structure. In Lecce, data were observed at continuous locations occurring within a defined spatial domain (geostatistical data). Therefore, the spatial effect was included via the stochastic partial differential equation approach. In Alicante, the pathogen was detected in all four of Purcell’s categories, illustrating the environmental plasticity of the subsp. multiplex. Here, none of the climatic covariates were retained in the selected model. Only two of Purcell’s categories were represented in Lecce. The mean diurnal range (bio2) and the mean temperature of the wettest quarter (bio8) were retained in the selected model, with a negative relationship with the presence of the pathogen. However, this may be due to the heterogeneous sampling distribution having a confounding effect with the climatic covariates. In both regions, the spatial structure had a strong influence on the models, but not the climatic covariates. Therefore, pathogen distribution was largely defined by the spatial relationship between geographic locations
Ecological, genetic and evolutionary drivers of regional genetic differentiation in Arabidopsis thaliana
Background: Disentangling the drivers of genetic differentiation is one of the cornerstones in evolution. This is because genetic diversity, and the way in which it is partitioned within and among populations across space, is an important asset for the ability of populations to adapt and persist in changing environments. We tested three major hypotheses accounting for genetic differentiation—isolation-by-distance (IBD), isolation-by-environment (IBE) and isolation-by-resistance (IBR)—in the annual plant Arabidopsis thaliana across the Iberian Peninsula, the region with the largest genomic diversity. To that end, we sampled, genotyped with genome-wide SNPs, and analyzed 1772 individuals from 278 populations distributed across the Iberian Peninsula.
Results: IBD, and to a lesser extent IBE, were the most important drivers of genetic differentiation in A. thaliana. In other words, dispersal limitation, genetic drift, and to a lesser extent local adaptation to environmental gradients, accounted for the within- and among-population distribution of genetic diversity. Analyses applied to the four Iberian genetic clusters, which represent the joint outcome of the long demographic and adaptive history of the species in the region, showed similar results except for one cluster, in which IBR (a function of landscape heterogeneity) was the most important driver of genetic differentiation. Using spatial hierarchical Bayesian models, we found that precipitation seasonality and topsoil pH chiefly accounted for the geographic distribution of genetic diversity in Iberian A. thaliana.
Conclusions: Overall, the interplay between the influence of precipitation seasonality on genetic diversity and the effect of restricted dispersal and genetic drift on genetic differentiation emerges as the major forces underlying the evolutionary trajectory of Iberian A. thaliana
El quiste óseo aneurismático en niños y adolescentes
Desde el año 1981 hasta el año 1996 hemos tratado en nuestro servicio un total de 12 pacientes con diagnóstico de Quiste Óseo Aneurismático (QOA). Esta entidad clÃnico-patológica continúa hoy teniendo un origen incierto que en la mayorÃa de las ocasiones no puede reconocerse. Los tratamientos empleados fueron: legrado e injerto óseo en siete casos, resección en bloque en tres casos, y en 2 casos tratamiento expectante.
Los resultados del tratamiento quirúrgico fueron satisfactorios en el 75% de los casos, encontrando un 25% de recidivas, que ocurrieron en los pacientes más jóvenes con quistes más agresivos. El tiempo medio de seguimiento fue de 4 años (mÃnimo 1 - máximo 8). Realizamos en el trabajo, además, una comparación con otros métodos de tratamiento publicados como son la crioterapia intratumoral y la embolizacón arterial selectiva, los cuales encontramos de utilidad relativa ya que requieren una alta especialización y una selección precisa de los casos. También la radioterapia que tiene una utilidad restringida a aquellos casos de inaccesibilidad operatoria.From 1981 to 1996 twelve patients were treated in our orthopaedic department with the diagnosis of Aneurismal Bone Cyst (ABC). This pathologic and clinical entity has an unknown etiology that in the majority of cases it can¿t be elucidated. The threatment was: curettage and bone graft in seven cases; in bloc excision in three cases and expectant in two. Surgical treatment results were satisfactory in 75% of cases, with 25% of local recurrences that took place in younger patients with more aggressive cysts. Mean follow-up was four years (range: 1-8). In this study we make a comparison with other methods of treatment reported like intratumoral criotherapy and selective arterial embolization. We find these methods of relative utility due to their high level of orthopaedist specialization and precise selection of cases. The radiotherapy has restricted application to cases of unresectable tumours
Incorporating Biotic Information in Species Distribution Models: A Coregionalized Approach
In this work, we discuss the use of a methodological approach for modelling spatial
relationships among species by means of a Bayesian spatial coregionalized model. Inference and
prediction is performed using the integrated nested Laplace approximation methodology to reduce
the computational burden. We illustrate the performance of the coregionalized model in species
interaction scenarios using both simulated and real data. The simulation demonstrates the better
predictive performance of the coregionalized model with respect to the univariate models. The case
study focus on the spatial distribution of a prey species, the European anchovy (Engraulis encrasicolus),
and one of its predator species, the European hake (Merluccius merluccius), in the Mediterranean sea.
The results indicate that European hake and anchovy are positively associated, resulting in improved
model predictions using the coregionalized model.Postprin
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