EFECTO DE LA REFRIGERACIÓN SOBRE LA MOTILIDAD, INTEGRIDAD DE MEMBRANA ACROSOMAL Y REACCIÓN ACROSOMAL EN ESPERMATOZOIDES CANINOS

Métodos de preservación de espermatozoides mediante la refrigeración o el congelamiento han sido desarrollados para espermatozoides caninos; sin embargo, la tasa de fecundación artificial es baja, posiblemente por daños celulares aún no determinados. El objetivo de este estudio fue evaluar el efecto de la refrigeración sobre la motilidad, actividad mitocondrial, integridad de membrana acrosomal y reacción acrosomal en espermatozoides caninos incubados en tres medios distintos (Ferp Talp, CCMm, Sp Talp), utilizando nuevas metodologías (Mito Tracker, Lyso Tracker, SBTI). Los resultados indicaron una disminución significativa (p<0.05) en la motilidad, viabilidad e integridad del acrosoma en espermatozoides refrigerados en comparación con los frescos; así como una dinámica de reacción diferente en espermatozoides refrigerados respecto a los frescos. Por otra parte, los medios Sp Talp y CCMm dieron mejores resultados en mantenimiento de la motilidad, actividad mitocondrial e integridad de membrana acrosomal.Preservation methods of spermatozoa using refrigeration have been developed for canine sperm; however, the rate of fertilization is still low, possibly due to cell damage for unknown reasons. The objective of this study was to evaluate the effect of refrigeration upon motility, mitochondrial activity, acrosomal membrane integrity, and acrosomal reaction in dog sperm incubated in three culture media (Ferp Talp, CCMm, Sp Talp) using new methodologies (Mito Tracker, Lyso Tracker, SBTI). The results indicated that exist a significant decrease (p<0.05) in motility, mitochondrial activity, and acrosomal membrane integrity in refrigerated sperm in comparison with fresh sperm. Also, the dynamic of acrosomal reaction was different in refrigerated sperm in comparison with fresh sperm. The Sp Talp and CCMm media showed the best results in holding the mitochondrial activity and acrosomal membrane integrity

A novel learning environment for undergraduate mathematics courses

This work presents a scaffolding design of learning objects as auxiliaries in the teaching-learning of mathematics at undergraduate level, through an electronic learning platform developed for using in formal mathematics courses. Its design is based on the results of surveying a group of mathematics teachers in the undergraduate fields of Science and Engineering in Mexico, about different aspects of their teaching practice. This survey is consistent with other national and international studies that highlight a series of problems found in the undergraduate fields of Science and Engineering. Guidelines for the development of this kind of  learning objects were established, which leads to curricular changes that will result in an adequate process of integrating the use of technology in the classroom. An important feature of these objects is flexibility as they are helpful tools in the innovative design process. A grounded model for the creation of teaching materials is proposed, including elements that facilitate their use, and thus, it is concluded that the use of these tools is a factor that can help alleviate some of the learning problems currently present in undergraduate level mathematics courses.&nbsp

VOLUMEN 16, NÚMERO 30 (1983-1984)

PROYECTO GEOTÉRMICO CHILES - CERRO NEGRO. Lozano, E.; Cruz, L.ZONAS HIDROGEOLÓGICAS DE COLOMBIA. Lobo-Guerrero, A.ESTUDIO GEOQUÍMICO Y PETROGRÁFICO DE ROCAS SUBVOLCÁNICAS ENTRE LA QUEBRADA CHIRAPOTO Y EL RÍO ARQUÍA (DEPARTAMENTO DE ANTIOQUIA Y CALDAS). Sánchez, L. H.; Parra, R. A.; Ortíz, F.GEOLOGÍA Y EXPERIENCIAS CONSTRUCTIVAS EN EL TÚNEL TUNJITA. Tejada, S. E.CONTRIBUCIÓN AL CONOCIMIENTO DEL PALEOZOICO SUPERIOR EN LA SECCIÓN QUETAME - VILLAVICENCIO. Cortés, R.; De La Espriella, R.TECTÓNICA GRAVITACIONAL EN LA CORDILLERA ORIENTAL AL ESTE DE LA FALLA DE BOYACÁ (DEPARTAMENTO DE BOYACÁ). Reyes, Ch. I.AMBIENTES GEOLÓGICOS URANÍFEROS EN COLOMBIA. Ortega Montero, C

VOLUMEN 16, NÚMERO 30 (1983-1984)

PROYECTO GEOTÉRMICO CHILES - CERRO NEGRO. Lozano, E.; Cruz, L.ZONAS HIDROGEOLÓGICAS DE COLOMBIA. Lobo-Guerrero, A.ESTUDIO GEOQUÍMICO Y PETROGRÁFICO DE ROCAS SUBVOLCÁNICAS ENTRE LA QUEBRADA CHIRAPOTO Y EL RÍO ARQUÍA (DEPARTAMENTO DE ANTIOQUIA Y CALDAS). Sánchez, L. H.; Parra, R. A.; Ortíz, F.GEOLOGÍA Y EXPERIENCIAS CONSTRUCTIVAS EN EL TÚNEL TUNJITA. Tejada, S. E.CONTRIBUCIÓN AL CONOCIMIENTO DEL PALEOZOICO SUPERIOR EN LA SECCIÓN QUETAME - VILLAVICENCIO. Cortés, R.; De La Espriella, R.TECTÓNICA GRAVITACIONAL EN LA CORDILLERA ORIENTAL AL ESTE DE LA FALLA DE BOYACÁ (DEPARTAMENTO DE BOYACÁ). Reyes, Ch. I.AMBIENTES GEOLÓGICOS URANÍFEROS EN COLOMBIA. Ortega Montero, C

Influence of Low-Degree High-Order p-Mode Splittings on the Solar Rotation Profile

The solar rotation profile is well constrained down to about 0.25 R thanks to the study of acoustic modes. Since the radius of the inner turning point of a resonant acoustic mode is inversely proportional to the ratio of its frequency to its degree, only the low-degree p modes reach the core. The higher the order of these modes, the deeper they penetrate into the Sun and thus they carry more diagnostic information on the inner regions. Unfortunately, the estimates of frequency splittings at high frequency from Sun-as-a-star measurements have higher observational errors due to mode blending, resulting in weaker constraints on the rotation profile in the inner core. Therefore inversions for the solar internal rotation use only modes below 2.4 mHz for l < 4. In the work presented here, we used an 11.5 year-long time series to compute the rotational frequency splittings for modes l < 4 using velocities measured with the GOLF instrument. We carried out a theoretical study of the influence of the low-degree modes in the region 2 to 3.5 mHz on the inferred rotation profile as a function of their error bars.Comment: Accepted for publication in Solar Physics. 17 Pages, 9 figure

Evolución paleohidrogeológica y paleohidrológica de la turbera de Padul.Aplicación al almacenamiento de residuos radiactivos

El estudio de la turbera de Padul (Granada) se inició durante el 3er Plan de I+D de la Empresa Nacional de Residuos Radiactivos SA en el marco de un Proyecto financiado por la UE “Evidency from Quaternary Infills Palaeohydrogeology-EQUIP” y de otro proyecto “PALEOCLIMA”, financiado conjuntamente por ENRESA y el Consejo de Seguridad Nuclear (CSN)

Evolución paleohidrogeológica y paleohidrológica de la turbera de Padul.Aplicación al almacenamiento de residuos radiactivos

El estudio de la turbera de Padul (Granada) se inició durante el 3er Plan de I+D de la Empresa Nacional de Residuos Radiactivos SA en el marco de un Proyecto financiado por la UE “Evidency from Quaternary Infills Palaeohydrogeology-EQUIP” y de otro proyecto “PALEOCLIMA”, financiado conjuntamente por ENRESA y el Consejo de Seguridad Nuclear (CSN)

Evolución paleoclimática del sur de la Península Ibérica a partir del registro de la cuenca de Guadix-Baza: un modelo paleoclimático perimediterráneo

El análisis paleoambiental del registro estratigráfico del sector oriental de la cuenca de Guadix-Baza (Granada) se realizó en el marco del 3er Plan de I+D de la Empresa Nacional de Residuos Radiactivos SA junto con un Proyecto financiado por la UE “Evidency from Quaternary Infills Palaeohydrogeology- EQUIP” y otro proyecto “PALEOCLIMA”, conjuntamente financiado por ENRESA y el Consejo de Seguridad Nuclear (CSN)

Charge separation relative to the reaction plane in Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}}= 2.76 TeV

Measurements of charge dependent azimuthal correlations with the ALICE detector at the LHC are reported for Pb-Pb collisions at $\sqrt{s_{\rm NN}} = 2.76$ TeV. Two- and three-particle charge-dependent azimuthal correlations in the pseudo-rapidity range $|\eta| < 0.8$ are presented as a function of the collision centrality, particle separation in pseudo-rapidity, and transverse momentum. A clear signal compatible with a charge-dependent separation relative to the reaction plane is observed, which shows little or no collision energy dependence when compared to measurements at RHIC energies. This provides a new insight for understanding the nature of the charge dependent azimuthal correlations observed at RHIC and LHC energies.Comment: 12 pages, 3 captioned figures, authors from page 2 to 6, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/286

A note on comonotonicity and positivity of the control components of decoupled quadratic FBSDE

In this small note we are concerned with the solution of Forward-Backward Stochastic Differential Equations (FBSDE) with drivers that grow quadratically in the control component (quadratic growth FBSDE or qgFBSDE). The main theorem is a comparison result that allows comparing componentwise the signs of the control processes of two different qgFBSDE. As a byproduct one obtains conditions that allow establishing the positivity of the control process.Comment: accepted for publicatio