883 research outputs found

    Amino acid tissue levels and GABAa receptor binding in the developing rat cerebellum following status epilepticus

    Get PDF
    Incidence of status epilepticus (SE) is higher in children than in adults and SE can be induced in developing rats. The cerebellum can be affected after SE; however, consequences of cerebellar amino acid transmission have been poorly studied. The goal of this study was to determine amino acid tissue concentration and GABAA receptor binding in the immature rat cerebellum after an episode of SE. Thirteen-day-old (P13) rat pups received in- traperitoneal injections of lithium chloride (3 mEq/kg). Twenty hours later, on P14, SE was induced by subcutaneous injection of pilocarpine hydrochloride (60 mg/kg). Control ani- mals were given an equal volume of saline subcutaneously. Animals were killed 24 h after SE induction, the cerebellum was quickly removed, and the vermis and hemispheres were rapidly dissected out on ice. Amino acid tissue concentrations in the vermis and hemi- spheres were evaluated by HPLC and fluorescent detection. GABAA receptor binding in the medial vermis was analyzed by in vitro autoradiography. SE increased the tissue levels of the inhibitory amino acids taurine (80%) and alanine (91%), as well as glutamine (168%) in the cerebellar hemisphere; no changes were observed in the vermis. SE did not modify GABAA receptor binding in any cerebellar lobule from the vermis. Our data demonstrate that SE produces region-specific changes in amino acid concentrations in the developing cerebellum

    Chiral perturbation theory calculation for pn -> dpipi at threshold

    Get PDF
    We investigate the reaction pn -> dpipi in the framework of Chiral Perturbation Theory. For the first time a complete calculation of the leading order contributions is presented. We identify various diagrams that are of equal importance as compared to those recognized in earlier works. The diagrams at leading order behave as expected by the power counting. Also for the first time the nucleon-nucleon interaction in the initial, intermediate and final state is included consistently and found to be very important. This study provides a theoretical basis for a controlled evaluation of the non-resonant contributions in two-pion production reactions in nucleon-nucleon collisions.Comment: 24 pages, 3 figures, 3 table

    Towards a field theoretic understanding of NN->NNpi

    Get PDF
    We study the production amplitude for the reaction NN->NNpi up to next--to--leading order in chiral perturbation theory using a counting scheme that takes into account the large scale introduced by the initial momentum. In particular we investigate a subtlety that arises once the leading loop contributions are convoluted with the NN wavefunctions as demanded by the non--perturbative nature of the NN interaction. We show how to properly identify the irreducible contribution of loop diagrams in such type of reaction. The net effect of the inclusion of all next-to-leading order loops is to enhance the leading rescattering amplitude by a factor of 4/3, bringing its contribution to the cross section for pp->dpi+ close to the experimental value.Comment: 15 Pages, 5 Figure

    Métodos para estimar requerimientos de cal en suelos ácidos acrisoles ferricos en Xalapa, Veracruz, México

    Get PDF
    Por su ubicación geográfica, México posee regiones tropicales y subtropicales, dichas regiones están limitadas  por la marcada acidez  de los  suelos,  siendo  este  fenómeno  uno  de los  problemas  más importantes en la producción de algunos cultivos. La práctica que se utiliza con el propósito de neutralizar la acidez y corregir los problemas que ésta ocasiona es el encalado de los suelos, sin embargo, para realizar esta práctica, debe considerarse la cantidad de cal por aplicar. La necesidad de cal varía de un suelo a otro, dependiendo de su naturaleza o del cultivo de que se trate, por lo que esta se debe determinar pare cada uno en particular. El suelo utilizado en esta investigación se localiza en las fincas cafetaleras “Las Animas1’ y “El Progreso”, en el municipio de Xalapa, Ver. Los resultados de este trabajo muestran que los métodos Houba y Van Schouwenburg, Dunn y SMP-Simple permiten estimar RC, para los pH considerados, con mayor exactitud que los métodos de Keeney y Corey (1963), Adams y Evans (1962), Acidez hidrolítica o de Kappen modificado (1976), Acidez intercambiable (1970) y el de Morejon (1988)

    Application of Silver Nanoparticles for Water Treatment

    Get PDF
    In recent past development of silver nanoparticles and their application in the treatment of wastewaters is becoming a major area of research. It is mainly applicable to the removal of three major pollutants like pesticides, heavy metals, and microorganisms. Variety of synthesis techniques have been reported for preparation and characterization of silver nanoparticles. In our research, we synthesized Ag nanoparticles supported on ZrO2 and ZrO2-CeO2 by a “deposit-precipitation method” as the first step and later sequentially synthesized Ag-Au supported on ZrO2 and ZrO2-CeO2 by Redox method. Catalysts were evaluated in catalytic wet air oxidation (CWAO) of methyl tert-butyl ether and phenol. The CWAO is a liquid phase process for the treatment of organic pollutants operating at temperatures in the range of 100–325°C at 5–200 bar pressures. The selectivity and efficient of catalysts were evaluated by total organic carbon (TOC) and high-performance liquid chromatograph (HPLC). Ideally, the total mineralization of pollutants into CO2 and H2O is preferred

    Planck 2015 results. XXV. Diffuse low-frequency Galactic foregrounds

    Get PDF
    Interstellar and circumstellar matter.-- et al.We discuss the Galactic foreground emission between 20 and 100 GHz based on observations by Planck and WMAP. The total intensity in this part of the spectrum is dominated by free-free and spinning dust emission, whereas the polarized intensity is dominated by synchrotron emission. The Commander component-separation tool has been used to separate the various astrophysical processes in total intensity. Comparison with radio recombination line templates verifies the recovery of the free-free emission along the Galactic plane. Comparison of the high-latitude Hα emission with our free-free map shows residuals that correlate with dust optical depth, consistent with a fraction (≈30%) of Hα having been scattered by high-latitude dust. We highlight a number of diffuse spinning dust morphological features at high latitude. There is substantial spatial variation in the spinning dust spectrum, with the emission peak (in Iν) ranging from below 20 GHz to more than 50 GHz. There is a strong tendency for the spinning dust component near many prominent H ii regions to have a higher peak frequency, suggesting that this increase in peak frequency is associated with dust in the photo-dissociation regions around the nebulae. The emissivity of spinning dust in these diffuse regions is of the same order as previous detections in the literature. Over the entire sky, the Commander solution finds more anomalous microwave emission (AME) than the WMAP component maps, at the expense of synchrotron and free-free emission. This can be explained by the difficulty in separating multiple broadband components with a limited number of frequency maps. Future surveys, particularly at 5–20 GHz, will greatly improve the separation by constraining the synchrotron spectrum. We combine Planck and WMAP data to make the highest signal-to-noise ratio maps yet of the intensity of the all-sky polarized synchrotron emission at frequencies above a few GHz. Most of the high-latitude polarized emission is associated with distinct large-scale loops and spurs, and we re-discuss their structure. We argue that nearly all the emission at 40deg > l > −90deg is part of the Loop I structure, and show that the emission extends much further in to the southern Galactic hemisphere than previously recognised, giving Loop I an ovoid rather than circular outline. However, it does not continue as far as the “Fermi bubble/microwave haze”, making it less probable that these are part of the same structure. We identify a number of new faint features in the polarized sky, including a dearth of polarized synchrotron emission directly correlated with a narrow, roughly 20deg long filament seen in Hα at high Galactic latitude. Finally, we look for evidence of polarized AME, however many AME regions are significantly contaminated by polarized synchrotron emission, and we find a 2σ upper limit of 1.6% in the Perseus region.The Planck Collaboration acknowledges the support of: ESA; CNES and CNRS/INSU-IN2P3-INP (France); ASI, CNR, and INAF (Italy); NASA and DoE (USA); STFC and UKSA (UK); CSIC, MINECO, JA, and RES (Spain); Tekes, AoF, and CSC (Finland); DLR and MPG (Germany); CSA (Canada); DTU Space (Denmark); SER/SSO (Switzerland); RCN (Norway); SFI (Ireland); FCT/MCTES (Portugal); ERC and PRACE (EU). This research was supported by an ERC Starting (Consolidator) Grant (no. 307209) and STFC Consolidated Grant (no. ST/L000768/1).Peer Reviewe

    Planck 2015 results. XXII. A map of the thermal Sunyaev-Zeldovich effect

    Get PDF
    Cosmology (including clusters of galaxies).-- et al.We have constructed all-sky Compton parameters maps, y-maps, of the thermal Sunyaev-Zeldovich (tSZ) effect by applying specifically tailored component separation algorithms to the 30 to 857 GHz frequency channel maps from the Planck satellite. These reconstructed y-maps are delivered as part of the Planck 2015 release. The y-maps are characterized in terms of noise properties and residual foreground contamination, mainly thermal dust emission at large angular scales, and cosmic infrared background and extragalactic point sources at small angular scales. Specific masks are defined to minimize foreground residuals and systematics. Using these masks, we compute the y-map angular power spectrum and higher order statistics. From these we conclude that the y-map is dominated by tSZ signal in the multipole range, 20 <ℓ< 600. We compare the measured tSZ power spectrum and higher order statistics to various physically motivated models and discuss the implications of our results in terms of cluster physics and cosmology.The Planck Collaboration acknowledges the support of: ESA; CNES and CNRS/INSU-IN2P3-INP (France); ASI, CNR, and INAF (Italy); NASA and DoE (USA); STFC and UKSA (UK); CSIC, MINECO, J.A., and RES (Spain); Tekes, AoF, and CSC (Finland); DLR and MPG (Germany); CSA (Canada); DTU Space (Denmark); SER/SSO (Switzerland); RCN (Norway); SFI (Ireland); FCT/MCTES (Portugal); ERC and PRACE (EU).Peer Reviewe

    Planck intermediate results. XXXVI. Optical identification and redshifts of Planck SZ sources with telescopes at the Canary Islands observatories

    Get PDF
    Catalogs and data.-- et al.We present the results of approximately three years of observations of Planck Sunyaev-Zeldovich (SZ) sources with telescopes at the Canary Islands observatories as part of the general optical follow-up programme undertaken by the Planck Collaboration. In total, 78 SZ sources are discussed. Deep-imaging observations were obtained for most of these sources; spectroscopic observations in either in long-slit or multi-object modes were obtained for many. We effectively used 37.5 clear nights. We found optical counterparts for 73 of the 78 candidates. This sample includes 53 spectroscopic redshift determinations, 20 of them obtained with a multi-object spectroscopic mode. The sample contains new redshifts for 27 Planck clusters that were not included in the first Planck SZ source catalogue (PSZ1).The Planck Collaboration acknowledges the support of: ESA; CNES, and CNRS/INSU-IN2P3-INP (France); ASI, CNR, and INAF (Italy); NASA and DoE (USA); STFC and UKSA (UK); CSIC, MINECO, JA and RES (Spain); Tekes, AoF, and CSC (Finland); DLR and MPG (Germany); CSA (Canada); DTU Space (Denmark); SER/SSO (Switzerland); RCN (Norway); SFI (Ireland); FCT/MCTES (Portugal); ERC and PRACE (EU). A.S., R.B., H.L., and J.A.R.M. acknowledge financial support from the Spanish Ministry of Economy and Competitiveness (MINECO) under the 2011 Severo Ochoa Program MINECO SEV-2011-0187, and the Consolider-Ingenio project CSD2010-00064 (EPI: Exploring the Physics of Inflation).Peer Reviewe

    Planck 2015 results. XXVII. The second Planck catalogue of Sunyaev-Zeldovich sources

    Get PDF
    Catalogs and data.-- et al.We present the all-sky Planck catalogue of Sunyaev-Zeldovich (SZ) sources detected from the 29 month full-mission data. The catalogue (PSZ2) is the largest SZ-selected sample of galaxy clusters yet produced and the deepest systematic all-sky surveyof galaxy clusters. It contains 1653 detections, of which 1203 are confirmed clusters with identified counterparts in external data sets, and is the first SZ-selected cluster survey containing >103 confirmed clusters. We present a detailed analysis of the survey selection function in terms of its completeness and statistical reliability, placing a lower limit of 83% on the purity. Using simulations, we find that the estimates of the SZ strength parameter Y5R500are robust to pressure-profile variation and beam systematics, but accurate conversion to Y500 requires the use of prior information on the cluster extent. We describe the multi-wavelength search for counterparts in ancillary data, which makes use of radio, microwave, infra-red, optical, and X-ray data sets, and which places emphasis on the robustness of the counterpart match. We discuss the physical properties of the new sample and identify a population of low-redshift X-ray under-luminous clusters revealed by SZ selection. These objects appear in optical and SZ surveys with consistent properties for their mass, but are almost absent from ROSAT X-ray selected samples.The Planck Collaboration acknowledges the support of: ESA; CNES and CNRS/INSU-IN2P3-INP (France); ASI, CNR, and INAF (Italy); NASA and DoE (USA); STFC and UKSA (UK); CSIC, MINECO, JA, and RES (Spain); Tekes, AoF, and CSC (Finland); DLR and MPG (Germany); CSA (Canada); DTU Space (Denmark); SER/SSO (Switzerland); RCN (Norway); SFI (Ireland); FCT/MCTES (Portugal); ERC and PRACE (EU).Peer Reviewe
    corecore