Evaluación de tres diluyentes para semen porcino a tres temperaturas y el comportamiento del mejor en la inseminación artificial.

Maestría en CienciasMaestrí

Localized inhibition in the Drosophila mushroom body

Many neurons show compartmentalized activity, in which activity does not spread readily across the cell, allowing input and output to occur locally. However, the functional implications of compartmentalized activity for the wider neural circuit are often unclear. We addressed this problem in the Drosophila mushroom body, whose principal neurons, Kenyon cells, receive feedback inhibition from a non-spiking interneuron called the anterior paired lateral (APL) neuron. We used local stimulation and volumetric calcium imaging to show that APL inhibits Kenyon cells’ dendrites and axons, and that both activity in APL and APL’s inhibitory effect on Kenyon cells are spatially localized (the latter somewhat less so), allowing APL to differentially inhibit different mushroom body compartments. Applying these results to the Drosophila hemibrain connectome predicts that individual Kenyon cells inhibit themselves via APL more strongly than they inhibit other individual Kenyon cells. These findings reveal how cellular physiology and detailed network anatomy can combine to influence circuit function

Prevalencia de anemia infecciosa equina en el Departamento de Córdoba.

Se hizo un estudio serológico con el objeto de determinar la prevalencia de anemia infecciosa equina en el Departamento de Córdoba, Colombia, y conocer la distribución y espidemiología en esta zona. Bajo condiciones prácticas de manejo y asepsia, se hizo la toma de muestras de sangre a 400 equinos elegidos completamente al azar, en 130 fincas distribuídas uniformemente en los 25 municipios que en la actualidad conforman el Departamento de Córdoba. Los sueros fueron analizados para determinar la presencia de anticuerpos precipitantes específicos para la anemia, utilizando para ello la prueba de inmunodifusión en agar-gel descrita por Coggins. De un total de 396 sueros estudiados, 54 resultaron con reacción positiva a anemia. Por no encontrarse diferencias significativas en cuanto a presentación de la enfermedad en el Alto, Medio y Bajo Sinú, se considera que la enfermedad se encuentra uniformemente distribuida en todo el Departamento. Se encontró que la enfermedad tiende a propagarse más fácilmente en fincas donde la población equina es más permanente, y por tanto donde existe una relación más estrecha entre animales, que en las que están sometidas a desplazamiento continuo de animales. Se comprueba una vez mas el bajo índice de diseminación con características de mortalidad de la enfermedad. No hubo relación entre la presentación de la enfermedad y la edad, sexo ni especie equin

A mid-infrared imaging catalogue of post-asymptotic giant branch stars

The definitive version can be found at: http://onlinelibrary.wiley.com/ Copyright Royal Astronomical SocietyPost-asymptotic giant branch (post-AGB) stars are key objects for the study of the dramatic morphological changes of low- to intermediate-mass stars on their evolution from the AGB towards the planetary nebula stage. There is growing evidence that binary interaction processes may very well have a determining role in the shaping process of many objects, but so far direct evidence is still weak. We aim at a systematic study of the dust distribution around a large sample of post-AGB stars as a probe of the symmetry breaking in the nebulae around these systems. We used imaging in the mid-infrared to study the inner part of these evolved stars to probe direct emission from dusty structures in the core of post-AGB stars in order to better understand their shaping mechanisms. We imaged a sample of 93 evolved stars and nebulae in the mid-infrared using VLT spectrometer and imager for the mid-infrared (VISIR)/VLT, T-Recs/Gemini-South and Michelle/Gemini-North. We found that all the proto-planetary nebulae we resolved show a clear departure from spherical symmetry. 59 out of the 93 observed targets appear to be non-resolved. The resolved targets can be divided into two categories. (i) The nebulae with a dense central core, that are either bipolar and multipolar and (ii) the nebulae with no central core, with an elliptical morphology. The dense central torus observed likely hosts binary systems which triggered fast outflows that shaped the nebulae.Peer reviewe

VFISV: Very Fast Inversion of the Stokes Vector for the Helioseismic and Magnetic Imager

In this paper we describe in detail the implementation and main properties of a new inversion code for the polarized radiative transfer equation (VFISV: Very Fast inversion of the Stokes vector). VFISV will routinely analyze pipeline data from the Helioseismic and Magnetic Imager (HMI) on-board of the Solar Dynamics Observatory (SDO). It will provide full-disk maps (4096$\times$4096 pixels) of the magnetic field vector on the Solar Photosphere every 10 minutes. For this reason VFISV is optimized to achieve an inversion speed that will allow it to invert 16 million pixels every 10 minutes with a modest number (approx. 50) of CPUs. Here we focus on describing a number of important details, simplifications and tweaks that have allowed us to significantly speed up the inversion process. We also give details on tests performed with data from the spectropolarimeter on-board of the Hinode spacecraft.Comment: 23 pages, 9 figures (2 color). Submitted for publication to Solar Physic

Solar Intranetwork Magnetic Elements: bipolar flux appearance

The current study aims to quantify characteristic features of bipolar flux appearance of solar intranetwork (IN) magnetic elements. To attack such a problem, we use the Narrow-band Filter Imager (NFI) magnetograms from the Solar Optical Telescope (SOT) on board \emph{Hinode}; these data are from quiet and an enhanced network areas. Cluster emergence of mixed polarities and IN ephemeral regions (ERs) are the most conspicuous forms of bipolar flux appearance within the network. Each of the clusters is characterized by a few well-developed ERs that are partially or fully co-aligned in magnetic axis orientation. On average, the sampled IN ERs have total maximum unsigned flux of several 10^{17} Mx, separation of 3-4 arcsec, and a lifetime of 10-15 minutes. The smallest IN ERs have a maximum unsigned flux of several 10^{16} Mx, separations less than 1 arcsec, and lifetimes as short as 5 minutes. Most IN ERs exhibit a rotation of their magnetic axis of more than 10 degrees during flux emergence. Peculiar flux appearance, e.g., bipole shrinkage followed by growth or the reverse, is not unusual. A few examples show repeated shrinkage-growth or growth-shrinkage, like magnetic floats in the dynamic photosphere. The observed bipolar behavior seems to carry rich information on magneto-convection in the sub-photospheric layer.Comment: 26 pages, 14 figure

Creating advanced Quizzes using Moodle

Taking on the role of adviser, the teacher must now assess the student´s learning process, not merely to sanction his results but to help the student achieve his best results through a constant supervision of his work. In this way, even though there may be final exams, these won´t be the only means of assessment. Sometimes the great amount of work that constant supervision implies may prove to be cumbersome. In Spain the new titles have meant moving from a training model mainly expository type and based on final exams, towards a model linking theory and practice, to promote the effort and cooperative learning, facilitate learning through libraries, virtual campus and resource centers for learning and research, and assess learning through continuous assessment systems. Assuming the role of counselor, the teacher must now evaluate the process of student learning, not merely to punish their results, but should help to meet objectives through continuous monitoring of their work. Thus, although they may be final exams are not the only methods of assessment. They will predominate procedures to facilitate the monitoring of student learning during their university life: objective evidence (true / false, multiple choice, matching elements ...), short-answer tests, extended-response tests, development, testing oral, self-evaluation systems ... anyway a greater variety of tools. For this reason it is useful to employ questionnaires using Moodle. In short, if our purpose is to use Moodle to assess the student´s competence acquired through an exam, calculated question types are very useful to generate questions in this virtual domain. Therefore each student will have different questions and we will avoid situations in which the students share the answers since they will have to know the procedure to arrive at the solution.Isabel Escobar wishes to acknowledge the Ministerio de Economía y Competitividad the support throughout the grant DPI2012-32994

Small-scale solar magnetic fields

As we resolve ever smaller structures in the solar atmosphere, it has become clear that magnetism is an important component of those small structures. Small-scale magnetism holds the key to many poorly understood facets of solar magnetism on all scales, such as the existence of a local dynamo, chromospheric heating, and flux emergence, to name a few. Here, we review our knowledge of small-scale photospheric fields, with particular emphasis on quiet-sun field, and discuss the implications of several results obtained recently using new instruments, as well as future prospects in this field of research.Comment: 43 pages, 18 figure

An innovative practice in the Physics laboratory: radiofrequency electromagnetic fields personal exposure

The evolution of the species has led us to adapt and live in an environment of electromagnetic waves of low frequency and low intensity of natural origin: proceeding from the Sun and Storms. In addition, we have gotten used to the Earth’s weak magnetic field, which is practically stationary. However, human activity has altered this natural balance with more intense electromagnetic fields and with a very different spectral distribution of frequencies. In the past two decades, personal exposure to Radiofrequency Electromagnetic Fields (RF-EMF) has experimented an important increase due to the development of the information society, and at some point, we have wondered whether these have any negative effects on health, some out of concern and some out of curiosity. Parallel to the increase of the exposure to RF-EMF, the concern regarding the potential health effects has increased. Among the most feared effects, stands out the possible relationship of the RF-EMF with some diseases of the brain of unspecified causes, which has motivated numerous epidemiological studies. However, many of these studies have focused almost exclusively in the location of the antennas of mobile phones, and not in involving the participants to disseminate the results with society. In this context, the use of personal Expometers allows to study the RF-EMF exposition in great detail (spatial, temporary, number of bands, precision, etc.) and/or characterize the exposure level of the population in different micro environments, where it is possible to study if there is spatial correlation with the incidence of any disease. Some studies propose alternatives to assess exposure in different micro environments, using different models elaborated from point measurements or elaborating exposure maps. In view of the growing public concern about the possible health effects of RF-EMF, we believe that a modern society must be sufficiently informed of all technological developments and possible health implications, and the best option is through education. At university level, laboratory practices can be developed where students participate during the measurement process, so they know the equipment and see the application of physics in this type of studies; in addition, they will be aware of the obtained results. We firmly believe that the work in the laboratory contributes in making learning more meaningful. What you manipulate is learned differently, you know the why, but also the how. For that reason, in this work we present the design and development of a laboratory practice for students of Physics for Computer Science Engineering the Degree in Computer Science, whose objective is to measure the intensity of the RF-EMF in 14 different frequency bands. The practice has been developed at the Faculty of Computer Science Engineering at the UCLM, located in the Campus of Albacete. The measurement instrument was Satimo's EME Spy 140 personal exposimeter, and data analysis was performed using EME Spy Analysis Software v3.20, Excel, Google Earth, ArcGIS Software and the Kriging method. With the results obtained, we realize that the recorded measurements are well below the basic restrictions and reference levels allowed by the European, Spanish and Castilla-La Mancha regulations respectively. We believe that this laboratory practice can be replicated in other national universities, as well as universities in other countries