1,329 research outputs found
External stimuli help restore post-partum ovarian activity in Pelibuey sheep
Post-partum anestrus is a problem on farms, and its duration depends on the frequency and intensity of suckling which affects reproduction and production efficiency to become a determining economic factor. The aim of this study was to determine the post-partum reproductive response in ewe to a "male effect" with an ovulation induction protocol of five days using progesterone and the application of a metabolic restorative (MR; Metabolase ®). One hundred and twenty females were randomly assigned to one of four treatments: T1: Continuous suckling (CS; n = 29), T2: CS + MR (n = 29), T3: CS + Male Effect (ME; n = 32), and T4: CS + MR + ME. The percentage of females in ovulation, weight changes among females and lambs, the onset of estrus, calving, fecundity, and prolificacy were also determined. The ovulation percentage was higher in CS + ME and CS + MR + ME (75.0 and 73.3%) than in the other treatments. Weight changes in females and lambs were different among periods. The onset of estrus was similar for CS and CS + MR (25.9 ± 1.9 and 25.7 ± 0.7 h, respectively). The calving percentage was higher for CS + MR (86.2%) than other treatments. Male presence positively affected the postpartum cyclic ovarian re-establishment and the metabolic restorative could even improve the fertility of hair ewes in continuous suckling with similar hormone protocolKeywords: Male effect, metabolic stimulation, post-partum anestru
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Controlled deformation of vesicles by flexible structured media
Liquid crystalline (LC) materials, such as actin or tubulin networks, are known to be capable of deforming the shape of cells. Here, elements of that behavior are reproduced in a synthetic system, namely, a giant vesicle suspended in a LC, which we view as a first step toward the preparation of active, anisotropic hybrid systems that mimic some of the functionality encountered in biological systems. To that end, we rely on a coupled particle-continuum representation of deformable networks in a nematic LC represented at the level of a Landau–de Gennes free energy functional. Our results indicate that, depending on its elastic properties, the LC is indeed able to deform the vesicle until it reaches an equilibrium, anisotropic shape. The magnitude of the deformation is determined by a balance of elastic and surface forces. For perpendicular anchoring at the vesicle, a Saturn ring defect forms along the equatorial plane, and the vesicle adopts a pancake-like, oblate shape. For degenerate planar anchoring at the vesicle, two boojum defects are formed at the poles of the vesicle, which adopts an elongated, spheroidal shape. During the deformation, the volume of the topological defects in the LC shrinks considerably as the curvature of the vesicle increases. These predictions are confirmed by our experimental observations of spindle-like shapes in experiments with giant unilamellar vesicles with planar anchoring. We find that the tension of the vesicle suppresses vesicle deformation, whereas anchoring strength and large elastic constants promote shape anisotropy
Aplicaciones en la región de Murcia de la información de ocupación de suelo en España (SIOSE)
Finalizadas las tareas del proyecto del Sistema de Información de Ocupación del Suelo en España (SIOSE), se
plantea el aprovechamiento de la información obtenida de las múltiples bases de datos geográficas. En esta nueva
fase, se ha propuesto desarrollar herramientas que faciliten la explotación de dichas bases de datos geográficas,
mediante un conjunto de aplicaciones software. Además, y como un primer paso hacia la integración dentro de una
infraestructura de datos espaciales (IDE) regional, ofrecer servicios basados en los estándares de publicación de
información espacial en internet según el Open Geospatial Consortium (OGC), que permitan la visualización y consul-
ta de los datos elaborados, con el objetivo de su difusión con el mayor grado posible.With the project completed, the information system of land use in Spain (SIOSE) takes the opportunity to use the
information obtained from multiple geographic databases. In this new phase, it is proposed to develop tools that
facilitate the work of these geographic databases through a set of software applications. In addition, as a first step
towards integration into a regional spatial data infrastructure (SDI), providing standards-based services for spatial
information published online by the Open Geospatial Consortium (OGC) which enable visualization and query the
data produced with the aim of its distribution with the greatest possible degree
PATRONES DE LA MACROFAUNA EDAFICA EN UN CULTIVO DE ZEA MAIZ DURANTE LA FASE POSTCOSECHA EN LA MANCHA, VERACRUZ, MEXICO
The soil macrofauna of a cornfield was studied during the fallow period in El Centro de Investigaciones Costeras "La Mancha", Veracruz. Patterns of soil macrofauna density, spatial distribution and diversity were described and their relationships with soil temperature, moisture, organic matter and pH were explored. Four strategies were combined to undertake this aim: a) sampling of soil macrofauna was carried out in seven ten cm soil layers from 0 to 70 cm depth; b) soil macrofauna was identified to morphospecies level; c) the size of morphospecies aggregations was determined following a the two-term local quadrat variance method (TTLQV); d) analysis of canonical correspondence was used to arrange morphospecies distribution in an spatial and environmental framework of reference. Density of soil macrofauna in the studied site seems to be the lowest value ever recorded in similar studies (246 individuals m-2). Forty-six morphospecies were collected that are mainly distributed in the top 20 cm soil layer and present an aggregated horizontal pattern of distribution. The diameter of aggregations of Oligochaeta juveniles, larvae of Tenebrionidae and Diplopoda juveniles was >1.5m, 0.9 m and 1.2 m respectively. It was possible to arrange different groups of soil Macrofauna according with their ranges of tolerance to environmental variables. Therefore, it is suggested that these patterns do reflect preferences of soil biota to microenvironments and do respond to soil degradation.Estudiamos la macrofauna del suelo de un cultivo de Zea maiz durante la fase postcosecha en el Centro de Investigaciones Costeras La Mancha, Veracruz. Describimos patrones de densidad, distribución espacial y diversidad en relación con la temperatura, humedad y pH del suelo. Para esto conjuntamos cuatro estrategias: a) muestreamos la macrofauna en estratos de 10 cm hasta los 70 cm de profundidad; b) separamos la fauna a nivel de morfoespecie; c) estimamos el tamaño de las agregaciones de las morfoespecies mediante una técnica de cuadrante-varianza; y d) ordenamos, mediante un análisis de correspondencia canónica, morfoespecies y estratos en un marco de referencia ambiental. La densidad de la macrofauna del suelo estudiado es la más baja reportada hasta la fecha para agroecosistemas en el mundo (246 individuos/m2). Colectamos 46 morfoespecies, que se distribuyeron generalmente en el primer o segundo estrato del suelo y presentaron una distribución agregada. El diametro de las agregaciones de los Oligochaeta juveniles fue superior a 1.5 m y para las larvas de Tenebrionidae y los Diplopoda juveniles fue de 0.9 y 1.2 m, respectivamente. Debido a que es posible separar distintos grupos de acuerdo con sus rangos de tolerancia a la temperatura, pH, humedad y materia orgánica en el suelo, es factible que los patrones de distribución registrados sean un reflejo de las preferencias de la biota a diferentes microambientes y al estado de degradación del suelo
Modulated-laser source induction system for remote detection of infrared emissions of high explosives using laser-induced thermal emission
In a homeland security setting, the ability to detect explosives at a distance is a top
security priority. Consequently, the development of remote, noncontact detection systems continues
to represent a path forward. In this vein, a remote detection system for excitation of infrared
emissions using a CO2 laser for generating laser-induced thermal emission (LITE) is a
possible solution. However, a LITE system using a CO2 laser has certain limitations, such
as the requirement of careful alignment, interference by the CO2 signal during detection, and
the power density loss due to the increase of the laser image at the sample plane with the detection
distance. A remote chopped-laser induction system for LITE detection using a CO2 laser
source coupled to a focusing telescope was built to solve some of these limitations. Samples of
fixed surface concentration (500 μg∕cm2) of 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) were
used for the remote detection experiments at distances ranging between 4 and 8 m. This system
was capable of thermally exciting and capturing the thermal emissions (TEs) at different times in
a cyclic manner by a Fourier transform infrared (FTIR) spectrometer coupled to a gold-coated
reflection optics telescope (FTIR-GT). This was done using a wheel blocking the capture of TE
by the FTIR-GT chopper while heating the sample with the CO2 laser. As the wheel moved, it
blocked the CO2 laser and allowed the spectroscopic system to capture the TEs of RDX.
Different periods (or frequencies) of wheel spin and FTIR-GT integration times were evaluated
to find dependence with observation distance of the maximum intensity detection, minimum
signal-to-noise ratio, CO2 laser spot size increase, and the induced temperature incremen
Evaluación de calidad de agua en un sistema ribereño utilizado para riego agrícola de subsistencia
En la evaluación del impacto de la contaminación en el ambiente, existen diversas herramientas y técnicas que se aplican para conocer la calidad ambiental de los recursos naturales. El objetivo de este trabajo fue evaluar la calidad del agua en un sistema ribereño en San Luis Potosí, México asociado al impacto del uso agrícola, urbano e industrial. Fueron establecidos cinco puntos de muestreo asociado a diversos usos y descargas residuales en donde se evaluaron 28 muestras durante cuatro días de muestro. Estas fueron distribuidas a los 20, 40, 60, 80, 100 y 120 minutos del trayecto determinando con un medidor multiparámetro los sólidos
disueltos totales (SDT), temperatura (T), conductividad eléctrica (CE), pH y oxígeno disuelto (OD). El resultado más destacado de las 28 muestras diarias y del total de 112 que los promedios oxígeno disuelto indican condición hipoxia que indica la desaparición de organismos y especies sensibles, concluyendo que el área ribereña requiere un constante monitoreo y diversificación de parámetros para evaluar su condición para actividades agrícolas.In the assessment of the impact of pollution on the environment, there are various tools and techniques that are applied to know the environmental quality of natural resources. The objective of this work was to evaluate water quality in a river system in San Luis Potosí, Mexico associated with the impact of agricultural, urban and industrial use. Five sampling points associated to various uses and residual discharges were established where 28 samples were evaluated during four days of sampling. The total dissolved solids (SDT), temperature (T), electrical conductivity (CE), pH and dissolved oxygen (OD) were distributed at 20, 40, 60, 80, 100 and 120 minutes of the path. The most outstanding result of the 28 daily samples and the total of 112 that dissolved oxygen averages indicate hypoxia condition indicating the disappearance of sensitive organisms and species, concluding that the riparian area requires constant monitoring and diversification of parameters to evaluate agricultural activities.Fil: Alcalá Jáuregui, J. A.
Universidad Autónoma de San Luis Potosí. Facultad de AgronomíaFil: Acosta Doporto Geiler, A.
Instituto Tecnológico Superior de los Ríos de Balancan (México)Fil: Rodríguez Ortiz, J.C.
Universidad Autónoma de San Luis Potosí. Facultad de AgronomíaFil: Hernández Montoya, A.
Universidad Autónoma de San Luis Potosí. Facultad de AgronomíaFil: Martínez Carretero, Eduardo.
Consejo Nacional de Investigaciones Científicas y TécnicasFil: Filippini, Maria Flavia.
Universidad Nacional de Cuyo. Facultad de Ciencias AgrariasFil: Díaz Flores, P. E.
Universidad Autónoma de San Luis Potosí. Facultad de AgronomíaFil: Lara Mireles, J. L.
Universidad Autónoma de San Luis Potosí. Facultad de Agronomí
Dispersal bahavior and long distance flight capacity of Monochamus galloprovincialis (Olievier 1795)
Analysis of remarkable bolides observed between June and July 2022 in the framework of the Southwestern EuropeMeteor Network
Some of the bright bolides spotted in the framework of the Southwestern Europe Meteor Network from June to July
2022 are discussed here. These were observed from Spain. Their absolute magnitude ranges from –6 to –11. Fireballs
included in this work were generated by different sources: the sporadic background, major meteoroid streams, and
poorly known streams.Spanish Ministry of
Science and Innovation (project PID2019-105797GB-I00). State
Agency for Research of the Spanish MCIU through the
“Center of Excellence Severo Ochoa” award to the Instituto
de Astrofísica de Andalucía (SEV-2017-0709). Spanish grant AYA
- RTI2018 – 098657 – J - I00 “LEO-SBNAF” (MCIU / AEI
/ FEDER, UE)
Maximally-localized generalized Wannier functions for composite energy bands
We discuss a method for determining the optimally-localized set of
generalized Wannier functions associated with a set of Bloch bands in a
crystalline solid. By ``generalized Wannier functions'' we mean a set of
localized orthonormal orbitals spanning the same space as the specified set of
Bloch bands. Although we minimize a functional that represents the total spread
sum_n [ _n - _n^2 ] of the Wannier functions in real space, our method
proceeds directly from the Bloch functions as represented on a mesh of
k-points, and carries out the minimization in a space of unitary matrices
U_mn^k describing the rotation among the Bloch bands at each k-point. The
method is thus suitable for use in connection with conventional
electronic-structure codes. The procedure also returns the total electric
polarization as well as the location of each Wannier center. Sample results for
Si, GaAs, molecular C2H4, and LiCl will be presented.Comment: 22 pages, two-column style with 4 postscript figures embedded. Uses
REVTEX and epsf macros. Also available at
http://www.physics.rutgers.edu/~dhv/preprints/index.html#nm_wan
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