110 research outputs found
Evapotranspiration of the brazilian Pampa biome: seasonality and influential factors
Experimentally characterizing evapotranspiration (ET) in different biomes around the
world is an issue of interest for different areas of science. ET in natural areas of the Brazilian Pampa
biome has still not been assessed. In this study, the actual ET (ETact) obtained from eddy covariance
measurements over two sites of the Pampa biome was analyzed. The objective was to evaluate the
energy partition and seasonal variability of the actual ET of the Pampa biome. Results showed that
the latent heat flux was the dominant component in available energy in both the autumnâwinter
(AW) and springâsummer (SS) periods. Evapotranspiration of the Pampa biome showed strong
seasonality, with highest ET rates in the SS period. During the study period, approximately 65% of
the net radiation was used for the evapotranspiration process in the Pampa biome. The annual mean
ET rate was 2.45 mm d1. ET did not show to vary significantly between sites, with daily values
very similar in both sites. The water availability in the Pampa biome was not a limiting factor for ET,
which resulted in a small difference between the reference ET and the actual ET. These results are
helpful in achieving a better understanding of the temporal pattern of ET in relation to the landscape
of the Pampa biome and its meteorological, soil, and vegetation characteristicsinfo:eu-repo/semantics/publishedVersio
Transcranial direct current stimulation (tDCS) reverts behavioral alterations and brainstem BDNF level increase induced by neuropathic pain model: Long-lasting effect
AbstractIntroductionNeuropathic pain (NP) is a chronic pain modality that usually results of damage in the somatosensory system. NP often shows insufficient response to classic analgesics and remains a challenge to medical treatment. The transcranial direct current stimulation (tDCS) is a non-invasive technique, which induces neuroplastic changes in central nervous system of animals and humans. The brain derived neurotrophic factor plays an important role in synaptic plasticity process. Behavior changes such as decreased locomotor and exploratory activities and anxiety disorders are common comorbidities associated with NP.ObjectiveEvaluate the effect of tDCS treatment on locomotor and exploratory activities, and anxiety-like behavior, and peripheral and central BDNF levels in rats submitted to neuropathic pain model.MethodsRats were randomly divided: Ss, SsS, SsT, NP, NpS, and NpT. The neuropathic pain model was induced by partial sciatic nerve compression at 14days after surgery; the tDCS treatment was initiated. The animals of treated groups were subjected to a 20minute session of tDCS, for eight days. The Open Field and Elevated Pluz Maze tests were applied 24h (phase I) and 7days (phase II) after the end of tDCS treatment. The serum, spinal cord, brainstem and cerebral cortex BDNF levels were determined 48h (phase I) and 8days (phase II) after tDCS treatment by ELISA.ResultsThe chronic constriction injury (CCI) induces decrease in locomotor and exploratory activities, increases in the behavior-like anxiety, and increases in the brainstem BDNF levels, the last, in phase II (one-way ANOVA/SNK, P<0.05 for all). The tDCS treatment already reverted all these effects induced by CCI (one-way ANOVA/SNK, P<0.05 for all). Furthermore, the tDCS treatment decreased serum and cerebral cortex BDNF levels and it increased these levels in the spinal cord in phase II (one-way ANOVA/SNK, P<0.05).ConclusiontDCS reverts behavioral alterations associated to neuropathic pain, indicating possible analgesic and anxiolytic tDCS effects. tDCS treatment induces changes in the BDNF levels in different regions of the central nervous system (CNS), and this effect can be attributed to different cellular signaling activations
Neutron-induced fission cross sections of Th 232 and U 233 up to 1 GeV using parallel plate avalanche counters at the CERN n_TOF facility
The neutron-induced fission cross sections of 232 Th and 233 U were measured relative to 235 U in a wide neutron energy range up to 1 GeV (and from fission threshold in the case of 232 Th , and from 0.7 eV in case of 233 U ), using the white-spectrum neutron source at the CERN Neutron Time-of-Flight (n_TOF) facility. Parallel plate avalanche counters (PPACs) were used, installed at the Experimental Area 1 (EAR1), which is located at 185 m from the neutron spallation target. The anisotropic emission of fission fragments were taken into account in the detection efficiency by using, in the case of 233 U , previous results available in EXFOR, whereas in the case of 232 Th these data were obtained from our measurement, using PPACs and targets tilted 45 ° with respect to the neutron beam direction. Finally, the obtained results are compared with past measurements and major evaluated nuclear data libraries. Calculations using the high-energy reaction models INCL + + and ABLA07 were performed and some of their parameters were modified to reproduce the experimental results. At high energies, where no other neutron data exist, our results are compared with experimental data on proton-induced fission. Moreover, the dependence of the fission cross section at 1 GeV with the fissility parameter of the target nucleus is studied by combining those ( p , f ) data with our ( n , f ) data on 232 Th and 233 U and on other isotopes studied earlier at n_TOF using the same experimental setup.Peer ReviewedArticle escrit per 81 autors/autores: D. TarrĂo ,
L. Tassan-Got, I. Duran, L. S. Leong, C. Paradela, L. Audouin, E. Leal-Cidoncha, C. Le Naour,
M. Caamaño, A. Ventura, S. Altstadt, J. Andrzejewski, M. Barbagallo, V. BĂ©cares, F. BecvĂĄ Ë Ër,F. Belloni,
E. Berthoumieux, J. Billowes, V. Boccone, D. Bosnar, M. Brugger, M. Calviani, F. Calviño, D. Cano-Ott,
C. Carrapiço, F. Cerutti, E. Chiaveri,M. Chin, N. Colonna, G. Cortés, M. A. Cortés-Giraldo, M. Diakaki,
C. Domingo-Pardo, N. Dzysiuk, C. Eleftheriadis, A. Ferrari, K. Fraval, S. Ganesan, A. R. GarcĂa, G. Giubrone,
M. B. Gómez-Hornillos, I. F. Gonçalves, E. Gonzålez-Romero,E. Griesmayer, C. Guerrero, F. Gunsing,
P. Gurusamy, D. G. Jenkins, E. Jericha, Y. Kadi, F. KĂ€ppeler,â D. Karadimos, P. Koehler, M. Kokkoris,
M. Krticka, J. Kroll, C. Langer, C. Lederer, H. Leeb, R. Losito, A. Manousos, J. Marganiec, T. MartĂnez,
C. Massimi, P. F. Mastinu,M. Mastromarco, M. Meaze, E. Mendoza, A. Mengoni, P. M. Milazzo, F. Mingrone,
M. Mirea,,â W. Mondalaers, A. Pavlik, J. Perkowski, A. Plompen, J. Praena, J. M. Quesada, T. Rauscher,
R. Reifarth, A. Riego, M. S. Robles, F. Roman, C. Rubbia, R. Sarmento, P. Schillebeeckx,S. Schmidt,
G. Tagliente, J. L. Tain, A. Tsinganis, S. Valenta, G. Vannini, V. Variale, P. Vaz, R. Versaci, M. J. Vermeulen,
V. Vlachoudis, R. Vlastou,A. Wallner, T. Ware, M. Weigand, C. WeiĂ, T. J. Wright, P. ĆœugecPostprint (published version
High accuracy 234U(n,f) cross section in the resonance energy region
New results are presented of the 234U neutron-induced fission cross section, obtained with high accuracy in the resonance region by means of two methods using the 235U(n,f) as reference. The recent evaluation of the 235U(n,f) obtained with SAMMY by L. C. Leal et al. (these Proceedings), based on previous n-TOF data [1], has been used to calculate the 234U(n,f) cross section through the 234U/235U ratio, being here compared with the results obtained by using the n-TOF neutron flux
Neutron cross-sections for advanced nuclear systems : The n-TOF project at CERN
© Owned by the authors, published by EDP Sciences, 2014 This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly citedThe study of neutron-induced reactions is of high relevance in a wide variety of fields, ranging from stellar nucleosynthesis and fundamental nuclear physics to applications of nuclear technology. In nuclear energy, high accuracy neutron data are needed for the development of Generation IV fast reactors and accelerator driven systems, these last aimed specifically at nuclear waste incineration, as well as for research on innovative fuel cycles. In this context, a high luminosity Neutron Time Of Flight facility, n-TOF, is operating at CERN since more than a decade, with the aim of providing new, high accuracy and high resolution neutron cross-sections. Thanks to the features of the neutron beam, a rich experimental program relevant to nuclear technology has been carried out so far. The program will be further expanded in the near future, thanks in particular to a new high-flux experimental area, now under construction.Peer reviewedFinal Published versio
238U(n, Îł) reaction cross section measurement with C 6D6 detectors at the n-TOF CERN facility
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 2.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly citedThe radiative capture cross section of 238U is very important for the developing of new reactor technologies and the safety of existing ones. Here the preliminary results of the 238U(n,Îł) cross section measurement performed at n-TOF with C6D6 scintillation detectors are presented, paying particular attention to data reduction and background subtraction.Peer reviewe
Determination of Escitalopram in Human Plasma by High Performance Liquid Chromatography-Tandem Mass Spectrometry
A rapid (3.0 min) and sensitive (LLOQ 0.5 ng/mL) analytical method for the quantitation of
Escitalopram (ETP) in human plasma is described. The method is based on High-Performance Liquid
Chromatography-Tandem Mass Spectrometry (LC-MS/MS) using paroxetine as internal standard (I.S.).
Sample preparation involved precipitation extraction with acetonitrile. The chromatographic separation
was achieved on a ACE C18 (125 x 4,6 mm) reversed-phase column and a mobile phase containing acetonitrile/water (60:50 v/v, add 0.2 % formic acid), in isocratic conditions. The target analytes were transferred into a triple quadrupole mass spectrometer equipped with an electrospray ionization source for
mass detection. The ion transitions selected for MRM detection were: m/z 325.2 > 109.2 and 330.0 > 192.0
for ETP and I.S., respectively. The assay was linear in the concentration range of 0.5-50 ng/mL. The mean
recovery for ETP was 97.69 %. Intra- and inter-day precision (R.S.D.) were < 10.5 % and <8.2 %, respectively and the accuracy (R.E.) was in the range ± 12.23 %. The method was successfully applied to a single
oral dose pharmacokinetics study in 28 healthy Brazilian human volunteers.Colegio de Farmacéuticos de la Provincia de Buenos Aire
The nucleosynthesis of heavy elements in Stars : The key isotope 25Mg
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 2.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly citedWe have measured the radiative neutron-capture cross section and the total neutron-induced cross section of one of the most important isotopes for the s process, the 25Mg. The measurements have been carried out at the neutron time-of-flight facilities n-TOF at CERN (Switzerland) and GELINA installed at the EC-JRC-IRMM (Belgium). The cross sections as a function of neutron energy have been measured up to approximately 300 keV, covering the energy region of interest to the s process. The data analysis is ongoing and preliminary results show the potential relevance for the s process.Peer reviewe
Towards the high-accuracy determination of the 238U fission cross section at the threshold region at CERN - N-TOF
The 238U fission cross section is an international standard beyond 2 MeV where the fission plateau starts. However, due to its importance in fission reactors, this cross-section should be very accurately known also in the threshold region below 2 MeV. The 238U fission cross section has been measured relative to the 235U fission cross section at CERN - n-TOF with different detection systems. These datasets have been collected and suitably combined to increase the counting statistics in the threshold region from about 300 keV up to 3 MeV. The results are compared with other experimental data, evaluated libraries, and the IAEA standards
- âŠ