71 research outputs found
Caracterización morfológica, fisicoquímica y de sanidad de una selección de clones multipatrón de guanábana (Annona muricata L.)
El objetivo del presente trabajo de investigación fue caracterizar e identificar injertos clonales multipatrón con características morfológicas, fisicoquímicas y de sanidad para obtener buenos rendimientos y calidad de pulpa del fruto en poblaciones de guanábana. Se utilizó la lista de descriptores, recomendado por CORPOICA para caracterizar el fruto y pulpa de las plantas clonales. Para la caracterización morfológica cuantitativa y cualitativa de la fruta se utilizó el software estadístico InfoStat, y para determinas las características más sobresalientes de la pulpa se usó el software SPSS Ver. 24. El análisis químico de la pulpa fue mediante las técnicas no paramétricas de Kruskal Wallis. En la caracterización cualitativa de la pulpa el 43,1% mostraron color blanco y blanco nieve, el 42,1% tuvo sabor ácido, el 57,9% tuvo textura media y el 44,7 % presento aroma medio y 36,8% aroma alto, el 50% mostro ser semi jugoso. El pH encontrado oscilo entre 4,70 y 2,92, con respecto a los sólidos solubles totales expresados en ºBrix tuvo en promedio 17,10. Se concluye que existe variabilidad genética en caracteres cualitativo y cuantitativo del fruto y pulpa en clones injertados y se encontraron diferencias en el análisis químico de la pulpa de plantas clonales
Los vacíos y omisiones de conservación de Coahuila, México, con especial referencia a sus tipos de vegetación
Contrasting vertical and horizontal representations of affect in emotional visual search
The final publication is available at Springer via http://dx.doi.org/ 10.3758/s13423-015-0884-6Independent lines of evidence suggest that the representation of emotional evaluation recruits both vertical and horizontal spatial mappings. These two spatial mappings differ in their experiential origins and their productivity, and available data suggest that they differ in their saliency. Yet, no study has so far compared their relative strength in an attentional orienting reaction time task that affords the simultaneous manifestation of both of them. Here we investigated this question using a visual search task with emotional faces. We presented angry and happy face targets and neutral distracter faces in top, bottom, left, and right locations on the computer screen. Conceptual congruency effects were observed along the vertical dimension supporting the ‘up=good’ metaphor, but not along the horizontal dimension. This asymmetrical processing pattern was observed when faces were presented in a cropped (Experiment 1) and whole (Experiment 2) format. These findings suggest that the ‘up=good’ metaphor is more salient and readily activated than the ‘right=good’ metaphor, and that the former outcompetes the latter when the task context affords the simultaneous activation of both mappings
First-principles quantum transport modeling of spin-transfer and spin-orbit torques in magnetic multilayers
We review a unified approach for computing: (i) spin-transfer torque in
magnetic trilayers like spin-valves and magnetic tunnel junction, where
injected charge current flows perpendicularly to interfaces; and (ii)
spin-orbit torque in magnetic bilayers of the type
ferromagnet/spin-orbit-coupled-material, where injected charge current flows
parallel to the interface. Our approach requires to construct the torque
operator for a given Hamiltonian of the device and the steady-state
nonequilibrium density matrix, where the latter is expressed in terms of the
nonequilibrium Green's functions and split into three contributions. Tracing
these contributions with the torque operator automatically yields field-like
and damping-like components of spin-transfer torque or spin-orbit torque
vector, which is particularly advantageous for spin-orbit torque where the
direction of these components depends on the unknown-in-advance orientation of
the current-driven nonequilibrium spin density in the presence of spin-orbit
coupling. We provide illustrative examples by computing spin-transfer torque in
a one-dimensional toy model of a magnetic tunnel junction and realistic
Co/Cu/Co spin-valve, both of which are described by first-principles
Hamiltonians obtained from noncollinear density functional theory calculations;
as well as spin-orbit torque in a ferromagnetic layer described by a
tight-binding Hamiltonian which includes spin-orbit proximity effect within
ferromagnetic monolayers assumed to be generated by the adjacent monolayer
transition metal dichalcogenide.Comment: 22 pages, 9 figures, PDFLaTeX; prepared for Springer Handbook of
Materials Modeling, Volume 2 Applications: Current and Emerging Material
Effects of anthropogenic activities on the heavy metal levels in the clams and sediments in a tropical river
The present study aimed to assess the effects of anthropogenic activities on the heavy metal levels in the Langat River by transplantation of Corbicula javanica. In addition, potential ecological risk indexes (PERI) of heavy metals in the surface sediments of the river were also investigated. The correlation analysis revealed that eight metals (As, Co, Cr, Fe, Mn, Ni, Pb and Zn) in total soft tissue (TST) while five metals (As, Cd, Cr, Fe and Mn) in shell have positively and significantly correlation with respective metal concentration in sediment, indicating the clams is a good biomonitor of the metal levels. Based on clustering patterns, the discharge of dam impoundment, agricultural activities and urban domestic waste were identified as three major contributors of the metals in Pangsun, Semenyih and Dusun Tua, and Kajang, respectively. Various geochemical indexes for a single metal pollutant (geoaccumulation index (I geo), enrichment factors (EF), contamination factor (C f) and ecological risk (Er)) all agreed that Cd, Co, Cr, Cu, Fe, Mn, Ni and Zn are not likely to cause adverse effect to the river ecosystem, but As and Pb could pose a potential ecological risk to the river ecosystem. All indexes (degree of contamination (C d), combined pollution index (CPI) and PERI) showed that overall metal concentrations in the tropical river are still within safe limit. River metal pollution was investigated. Anthropogenic activities were contributors of the metal pollution. Geochemical indexes showed that metals are within the safe limit
Experience shapes our odor perception but depends on the initial perceptual processing of the stimulus
New tools for measuring global academic performance
The study is on performance measurement in academia. It aims at developing and validating the measurement scale for the performance of higher institutions. The items were developed based on the extant literature. Data were collected via an online survey in which a questionnaire link was sent to 269 vice chancellors/presidents of the sampled universities. A total of 133 responses were retrieved at the end of the data collection period. This study used proportionate random sampling for sample selection. The goodness of measures was checked via field experts, academicians, and data analysis with SPSS. Overall, the alpha coefficient was .974. The outcome of exploratory factor analysis (EFA) exposed all factors loaded more than 0.50. The results revealed that the instrument was reliable and valid. Hence, the instrument developed was suitable to be used in examining the performance of higher institutions
Experiencia en el uso del disco compacto (CD-ROM) en la Unidad de Información y Documentación del CIAT
Correlation among thermosensitive period, estradiol response, and gonad differentiation in the sea turtle Lepidochelys olivacea
Reptile embryos with temperature sex determination have a thermosensitive period (TSP). The finding that exogenous estradiol (E2) overcomes the effect of male-promoting temperature led to the idea that temperature may regulate estrogen concentration in the gonad during TSP. Since interspecific variations in TSP and in the effect of exogenous E2 exist, we undertook a study in the olive ridley Lepidochelys olivacea. Four parameters were correlated: the TSP (time dimension), the thermosensitive stages (rate of development), gonad development (histological aspect), and the estradiol response. Two kinds of experiments were performed: (1) Eggs were shifted once, at different stages of development, from a male-promoting temperature to a female-temperature (or vice versa) for the remainder of development. (2) Eggs at male-promoting temperature were treated once with 6 or 12 μg of estradiol (E2) at various times of incubation. Sex ratio was established around hatching in each experimental series. We found that the temporal dimension of the TSP was around 7 days (Days 20-27 of incubation) at a male-promoting or a female-promoting temperature. The rate of development of the whole embryo and gonadal growth was faster at female-promoting temperature than at male-promoting temperature. Formation of the genital ridge began at stage 21-22 and histological differentiation of the gonads occurred around stage 26-27. Although these stages coincided with the TSP, at male-promoting temperature the thermosensitive stages occurred earlier (from stages 20-21 to stages 23-24) than at female-promoting temperature (from stages 23-24 to stages 26-27). Thus, at male promoting-temperature, sex was determined in embryos with incipient or undifferentiated gonads. In contrast, E2 treatment continued to feminize the gonads of embryos at a male-promoting temperature beyond the TSP up to stage 25-26, but the E2-induced ovaries were significantly smaller than temperature-induced ovaries. It is suggested that the doses of E2 used were higher than the concentration of endogenous E2 required for normal sex determination. The lack of correlation between sex determination and gonad differentiation suggests that irreversible molecular processes underlying sex determination occur earlier at male- than at female- promoting temperature. Results suggest that the male sex may be the default state and that the female condition must be imposed upon it
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