Selection and Agronomic Characterization of Leucaena spp. Genotypes for Cold Tolerance. I. Dry Matter Yield.

Biotypes of Leucaena spp (56) were evaluated in order to identify those with tolerance to low temperature and with desirable characteristics as a forage crop. Selection was done at two phases. Phase I: 92 days old seedlings (n=2800) were subjected at two temperatures treatments during 14 hours: T1= -8 °C and T2= -3 °C. Selection criteria was established as 50% of live leaves remained after treatments were applied. Phase II: Plants that survived phase I were planted at field conditions and agronomic characteristics were measured. Seventeen plants were selected from eleven different biotypes, resulting one from T1 and the rest from T2. Three plants showed good agronomic adaptation and greater chilling tolerance. Only one plant maintained live stem and meristematic tissue after a -8.8 °C freeze occurrence . Plants N° 2, 3, 5, 6, 8, 9, 10, 11, 12, 13, 15 and 16 were the most productive (Dry matter production)

Performance Portability Strategies for Grid C++ Expression Templates

One of the key requirements for the Lattice QCD Application Development as part of the US Exascale Computing Project is performance portability across multiple architectures. Using the Grid C++ expression template as a starting point, we report on the progress made with regards to the Grid GPU offloading strategies. We present both the successes and issues encountered in using CUDA, OpenACC and Just-In-Time compilation. Experimentation and performance on GPUs with a SU(3)$\times$SU(3) streaming test will be reported. We will also report on the challenges of using current OpenMP 4.x for GPU offloading in the same code.Comment: 8 pages, 4 figures. Talk presented at the 35th International Symposium on Lattice Field Theory, 18-24 June 2017, Granada, Spai

The nucleon spin and momentum decomposition using lattice QCD simulations

We determine within lattice QCD, the nucleon spin carried by valence and sea quarks, and gluons. The calculation is performed using an ensemble of gauge configurations with two degenerate light quarks with mass fixed to approximately reproduce the physical pion mass. We find that the total angular momentum carried by the quarks in the nucleon is $J_{u+d+s}{=}0.408(61)_{\rm stat.}(48)_{\rm syst.}$ and the gluon contribution is $J_g {=}0.133(11)_{\rm stat.}(14)_{\rm syst.}$ giving a total of $J_N{=}0.54(6)_{\rm stat.}(5)_{\rm syst.}$ consistent with the spin sum. For the quark intrinsic spin contribution we obtain $\frac{1}{2}\Delta \Sigma_{u+d+s}{=}0.201(17)_{\rm stat.}(5)_{\rm syst.}$. All quantities are given in the $\overline{\textrm{MS}}$ scheme at 2~GeV. The quark and gluon momentum fractions are also computed and add up to $\langle x\rangle_{u+d+s}+\langle x\rangle_g{=}0.804(121)_{\rm stat.}(95)_{\rm syst.}+0.267(12)_{\rm stat.}(10)_{\rm syst.}{=}1.07(12)_{\rm stat.}(10)_{\rm syst.}$ satisfying the momentum sum.Comment: Version published in PR

separate motion detecting mechanisms for first and second order patterns revealed by rapid forms of visual motion priming and motion aftereffect

Fast adaptation biases the perceived motion direction of a subsequently presented ambiguous test pattern (R. Kanai & F. A. Verstraten, 2005). Depending on both the duration of the adapting stimulus (ranging from tens to hundreds of milliseconds) and the duration of the adaptation-test blank interval, the perceived direction of an ambiguous test pattern can be biased towards the same or the opposite direction of the adaptation pattern, resulting in rapid forms of motion priming or motion aftereffect respectively. These findings were obtained employing drifting luminance gratings. Many studies have shown that first-order motion (luminance-defined) and second-order motion (contrast-defined) stimuli are processed by separate mechanisms. We assessed whether these effects also exist within the second-order motion domain. Results show that fast adaptation to second-order motion biases the perceived direction of a subsequently presented second-order ambiguous test pattern with similar time courses to that obtained for first-order motion. To assess whether a single mechanism could account for these results, we ran a cross-order adaptation condition. Results showed little or no transfer between the two motion cues and probes, suggesting a degree of separation between the neural substrates subserving fast adaptation of first- and second-order motion. © ARVO

¿Cuál es la crisis de los intelectuales en crisis? : algunos apuntes sobre la política y la cultura en el fin de siglo argentino

La ponencia en forma de apuntes, pone el foco de atención en algunas de las condiciones políticas y culturales que hicieron posible un estado del campo intelectual actual, mostrando cuáles han sido algunas de las notas salientes del debate intelectual sobre la política en los últimos años.Fil: Casco, José M.. Universidad de Buenos Aire

Nucleon scalar and tensor charges using lattice QCD simulations at the physical value of the pion mass

We present results on the light, strange and charm nucleon scalar and tensor charges from lattice QCD, using simulations with $N_f=2$ flavors of twisted mass Clover-improved fermions with a physical value of the pion mass. Both connected and disconnected contributions are included, enabling us to extract the isoscalar, strange and charm charges for the first time directly at the physical point. Furthermore, the renormalization is computed non-perturbatively for both isovector and isoscalar quantities. We investigate excited state effects by analyzing several sink-source time separations and by employing a set of methods to probe ground state dominance. Our final results for the scalar charges are $g_S^u = 5.20(42)(15)(12)$, $g_S^d = 4.27(26)(15)(12)$, $g_S^s=0.33(7)(1)(4)$, $g_S^c=0.062(13)(3)(5)$ and for the tensor charges $g_T^u = 0.782(16)(2)(13)$, $g_T^d = -0.219(10)(2)(13)$, $g_T^s=-0.00319(69)(2)(22)$, $g_T^c=-0.00263(269)(2)(37)$ in the $\overline{\rm MS}$ scheme at 2~GeV. The first error is statistical, the second is the systematic error due to the renormalization and the third the systematic arising from possible contamination due to the excited states.Comment: 20 pages and 13 figure

Attention modulates psychophysical and electrophysiological response to visual texture segmentation in humans

none5noTo investigate whether processing underlying texture segmentation is limited when texture is not attended, we measured orientation discrimination accuracy and visual evoked potentials (VEPs) while a texture bar was cyclically alternated with a uniform texture, either attended or not. Orientation discrimination was maximum when the bar was explicitly attended, above threshold when implicitly attended, and fell to just chance when unattended, suggesting that orientation discrimination based on grouping of elements along texture boundary requires explicit attention. We analyzed tsVEPs (variations in VEP amplitude obtained by algebraic of uniform-texture from segmented-texture VEPs) elicited by the texture boundary orientation discrimination task. When texture was unattended, tsVEPs still reflected local texture segregation. We found larger amplitudes of early tsVEP components (N75, P100, N150, N200) when texture boundary was parallel to texture elements, indicating a saliency effect, perhaps at V1 level. This effect was modulated by attention, disappearing when the texture was not attended, a result indicating that attention facilitates grouping by collinearity in the direction of the texture boundary.openCasco, C; Grieco, A; Campana, G; CORVINO M., P; Caputo, GIOVANNI BATTISTACasco, C; Grieco, A; Campana, G; CORVINO M., P; Caputo, GIOVANNI BATTIST

Strange nucleon electromagnetic form factors from lattice QCD

We evaluate the strange nucleon electromagnetic form factors using an ensemble of gauge configurations generated with two degenerate maximally twisted mass clover-improved fermions with mass tuned to approximately reproduce the physical pion mass. In addition, we present results for the disconnected light quark contributions to the nucleon electromagnetic form factors. Improved stochastic methods are employed leading to high-precision results. The momentum dependence of the disconnected contributions is fitted using the model-independent z-expansion. We extract the magnetic moment and the electric and magnetic radii of the proton and neutron by including both connected and disconnected contributions. We find that the disconnected light quark contributions to both electric and magnetic form factors are non-zero and at the few percent level as compared to the connected. The strange form factors are also at the percent level but more noisy yielding statistical errors that are typically within one standard deviation from a zero value.Comment: 10 pages, 11 figure

PARTICULAS FINAS EN EL AIRE DE LOCALES GASTRONOMICOS CON PARRILLA

La exposición a humo ambiental en lugares cerrados es peligrosa para la salud. Las partículas de hasta 2,5 micras son marcadores del humo en los lugares cerrados. Este estudio monitoreó la calidad de aire en 4 locales gastronómicos de Asunción, Paraguay, y algunas condiciones que influyen en los niveles de exposición explorados. Los niveles más altos de partículas encontrados fueron 9,9 μg/m3. En ninguno de los locales estudiados se detectaron fumadores. Falta mayor investigación sobre contaminación del aire en lugares cerrados para una mejor protección de la salud

Hemorragia Digestiva Alta No Varicosa. La experiencia del Centro Médico Bautista

Antecedentes: La hemorragia digestiva alta (HDA)constituye una de las emergencias médicas más frecuentes;el método diagnóstico estándar es la endoscopia digestivaalta y la terapéutica de elección la que combinael tratamiento médico y el endoscópico.Pacientes y método: Se realizó un estudio descriptivo,retrospectivo, de casos consecutivos deHDA atendidos en el Centro Médico Bautista entrejunio de 2.002 y diciembre de 2.004. Se investigó:características demográficas, cuadro clínico, hallazgosendoscópicos, tratamiento y resultados.Resultados: La serie incluye 55 casos: 30 hombresy 25 mujeres, con una edad promedio de 59años; 21 eran consumidores de AINEs. Los motivosde consulta fueron: melena 27 casos, hematemesis 6,hematemesis y melena 17, lipotimia 3 y rectorragia2. Las causas del sangrado fueron: Ulcera péptica 32casos, gastritis 19, esofagitis erosiva 2 y Síndromede Mallory-Weiss 2. Ningún paciente sometido atratamiento médico o endoscópico tuvo recaída delsangrado. Dos pacientes fueron sometidos a cirugíade urgencia. No se registró deceso alguno.Conclusión: la HDA afecta más frecuentementea varones, siendo la hematemesis y la melena los síntomascomunes; la úlcera péptica es la causa habitualdel sangrado y el manejo no operatorio conduce aresultados satisfactorios