Genetic Potential and Usefulness of Native Maize Populations in Developing Novel Germplasm for Current and Upcoming Goals

Traditional agricultural system is referring to the maize production based on indigenous or farmers knowledge and practices that have been developed through many generations. In the area of study, genetic maize diversity was explored by the expression of quantitative traits of the ear and the race classification approach. Evaluation results indicated that the native populations adapted to the transition and highland (above 2000 masl) areas, showed a contrasting yield response when they were evaluated at the intermediate environment; whereas, those populations adapted to the lowland and intermediate altitudes showed a satisfactory yield performance in both environments. The above performance pattern is essential because it may be useful to identify favorable alleles that, in a local population per se or through genetic combination, results in population changes in allele frequencies that could mitigate the effects of climate changes, particularly in maize populations adapted to highland altitudes. Selection procedures applied to a local adapted population can be managed attending different goals, including the conservation of genetic diversity (per se selection), and to develop novel germplasm. The introgression of foreign germplasm into a local population and the application of three selection cycles resulted in a novel variety (JAGUAN) adapted to a regional northeast Mexico environmental conditions

Decoherence in a double-slit quantum eraser

We study and experimentally implement a double-slit quantum eraser in the presence of a controlled decoherence mechanism. A two-photon state, produced in a spontaneous parametric down conversion process, is prepared in a maximally entangled polarization state. A birefringent double-slit is illuminated by one of the down-converted photons, and it acts as a single-photon two-qubits controlled not gate that couples the polarization with the transversal momentum of these photons. The other photon, that acts as a which-path marker, is sent through a Mach-Zehnder-like interferometer. When the interferometer is partially unbalanced, it behaves as a controlled source of decoherence for polarization states of down-converted photons. We show the transition from wave-like to particle-like behavior of the signal photons crossing the double-slit as a function of the decoherence parameter, which depends on the length path difference at the interferometer.Comment: Accepted in Physical Review

Multivariate manifold-valued curve regression in time

Fr\'echet global regression is extended to the context of bivariate curve stochastic processes with values in a Riemannian manifold. The proposed regression predictor arises as a reformulation of the standard least-squares parametric linear predictor in terms of a weighted Fr\'echet functional mean. Specifically, in our context, in this reformulation, the Euclidean distance is replaced by the integrated quadratic geodesic distance. The regression predictor is then obtained from the weighted Fr\'echet curve mean, lying in the time-varying geodesic submanifold, generated by the regressor process components involved in the time correlation range. The regularized Fr\'echet weights are computed in the time-varying tangent spaces. The uniform weak-consistency of the regression predictor is proved. Model selection is also addressed. A simulation study is undertaken to illustrate the performance of the spherical curve variable selection algorithm proposed in a multivariate framework.Comment: 24 pages, 8 Figure

Evidencia de exceso de fósforo dietético en lecherías con pastoreo rotacional de gramíneas tropicales.

On-farm phosphorus (P) balances are of importance for identifying critical control points in P feeding and management. In this study, P mass balances were constructed on fourteen pasture-based dairy farms of Puerto Rico, using production and management data. The farms ranged in animal units (AU, 454.5 kg) density from 1.23 to 27.50, with a mean of 7.53 AU/ha. Dietary P concentrations ranged between 5.02 and 7.24 g P/kg dry matter intake (DMI), with a mean of 6.16 g P/kg. These dietary P concentrations averaged 87% higher than the National Research Council recommendation of 3.4 g P/kg DMI. High dietary P concentrations were not associated with higher milk yields (P > 0.05). Manure P concentration of 13.2 g/kg fecal dry matter was, unexpectedly, not related to dietary concentration or total P intake. Estimates of total annual P excreted per cow ranged from 23.9 to 36.9 with a mean of 30.3 kg. Phosphorus excretion levels were 55% higher than those recommended for maintenance and milk production. Soil test P (Olsen) levels showed that 87% of the paddocks receiving manure application exceed agronomic critical P levels of 35 mg/kg.The on-farm mass balance showed annual P surpluses that ranged from 15.0 to 472.9 with a mean of 156.2 kg/ha. Reducing the P concentration in the diet and in inorganic fertilizer applied to fields, and implementing best management practices, will have the greatest and most immediate impact on reducing the excess P present on dairy farms of Puerto Rico, and will contribute to the optimization of P use for eventual sustainable milk production and water quality maintenance.El balance de fósforo (P) de la finca es de importancia para identificar los puntos críticos de control en la alimentación y manejo del P en las lecherías. En este estudio, los balances de masa de P en catorce lecherías se construyeron basándose en los datos de producción y manejo de cada finca evaluada. La carga animal fluctuó entre 1.2 y 27.5 unidades animal (UA, 454.5 kg), con una media de 7.5. La amplitud observada en la concentración de P dietético fue entre 5.02 y 7.24 g P/kg de materia seca consumida (MSC), con una media de 6.16. Estas concentraciones de P fueron 87% mayores que las recomendadas por el Consejo Nacional de Investigación (NRC), de 3.4 g P/kg MSC. Las altas concentraciones de P no fueron asociadas a una mayor producción de leche P > 0.05). La concentración de P en las heces fecales fue de 13.2 g/kg, un valor alto que, inesperadamente, no estuvo relacionado con la concentración dietética o con el consumo total de P. Los estimados de excreción anual total de P fluctuaron entre 23.9 y 36.9, con una media de 30.3 kg/vaca. Estos niveles de excreción fueron 55% mayores que los esperados basándose en las recomendaciones de P para mantenimiento y producción de leche. Los niveles de P en el suelo (Olsen) indican que 87% de los predios que recibieron aplicación de agua de charca de oxidación (desperdicios fecales) excedieron los niveles agronómicos críticos de 35 mg/kg. El balance de masa de P en la finca indicó excedentes anuales de P que fluctuaron entre 15.0 y 472.9 kg/ha, con una media de 156.2. Reducciones en la concentración de P en la dieta y en la cantidad de P aplicado en el fertilizante inorgánico y la implementación de mejores prácticas de manejo tendrán el mayor y más rápido efecto para controlar el exceso de P en las lecherías de Puerto Rico. Estas medidas contribuirán a la optimización del uso del P para lograr la producción sustentable de leche y mantener buena calidad de las aguas superficiales

Análisis biomecánico de la esgrima mediante sistemas optoelectrónicos de análisis de movimiento. Estudio de caso: deportista de alto rendimiento

En este artículo se presenta el estudio de la técnica deportiva para esgrima por medio de un análisis biomecánico, realizado con ayuda de sistemas optoelectrónicos que capturan en tiempo real los dos gestos más destacados, el paso adelante y el fondo, con el objetivo de caracterizar digitalmente la biomecánica para su posterior análisis cinemático y de esta manera describir la técnica que tiene el deportista en la ejecución del movimiento. Con este estudio se lograron caracterizar de una forma cuantitativa las curvas de posición, ángulos articulares, velocidades y aceleraciones de cada uno de los marcadores situados en el cuerpo del deportista. Este estudio se realizó en un deportista de alto rendimiento, destacado en la modalidad de espada.This article presents the study of fencing techniques through biomechanical analysis, using optoelectronic systems that capture in real time two main gestures: advance and lunge, with the objective to digitally characterize the biomechanics, for its further kinematical analysis to describe the fencer’s technique in the movement execution. This study was made to characterize position curves, joint angles, velocity and acceleration of each of the markers located on the athlete’s body, in a quantitative manner. This study was developed on a high performance athlete in sword modalit