Does ad libitum feeding during the peri-partum improve the sow feed intake and performances?

This study hypothesized that the ad libitum feeding of sows during the peri-partum may increase the neonatal survival of the piglets and the post-partum recovery of the sow. The aim of the study was to evaluate the effects of two peri-partum feeding strategies (ad libitum and stepped from day 110 of gestation to day 5 post-partum) on the feed intake, the reproductive performance of sows, as well as the survival of their piglets. A total of 90 Landrace x Large-White dams sired by Duroc were used. The sows were randomly assigned to feeding treatments by balancing body condition and parity between groups. The feed intake of the sows in the peri-partum was lower in the stepped than in the ad libitum strategy. The increase of the feeding level in the ad libitum sows was not counterbalanced by higher number of weaned piglets or shorter weaned to oestrus interval

Análisis del impacto de M-learning y la investigación científica relacionada

The deep penetration and global impact of mobile devices has led the scientific community to undertake a thorough analysis of the implications of this phenomenon. Researchers need to determine their true real effect and how they can best be used to manage information and build knowledge. This study has examined recent investigations on the subject of mobile learning and carried out a descriptive analysis of a sample of registers indexed on the Web of Science research platform in 2015-16. An exhaustive content analysis has revealed new areas where M-Learning is being implemented, especially in the teaching of foreign languages, the emergence of social interaction methodologies in Secondary Education, evolving forms of collaborative relationships, work with clearly defined student profiles and the use of virtual immersive and innovative spaces in Higher Education. This paper also emphasizes the presence of previously unknown, transcendent problems associated with M-learning, such as the collateral addiction effect, and its interference in the classroom. Finally, our study suggests that teachers could embrace these technological proposals and include them in their strategies. Indeed, it might be necessary to flip the process, so this research could be the start of the generation and design of innovative guidelines to manage these forms and content.La elevada penetración e impacto mundial de los dispositivos móviles obliga a la comunidad científica a hacer análisis rigurosos sobre las implicaciones de este fenómeno. Así, desde el contexto académico es necesario determinar sus efectos reales y cuáles son sus usos más adecuados para su aprovechamiento en la gestión de la información y la construcción del conocimiento. Para ello se examinan las recientes investigaciones sobre el tema del aprendizaje móvil y se realiza un análisis descriptivo de una muestra de registros indexados en la plataforma de investigación de Web of Science en el periodo 2015-2016. El exhaustivo análisis de contenido sobre estos registros ha destacado nuevos aspectos relevantes, como las áreas temáticas de mayor impacto, la irrupción de nuevas metodologías de interacción social en Educación Secundaria, formas emergentes de relaciones colaborativas, el trabajo con perfiles de estudiantes bien delimitados y el uso de innovaciones en espacios inmersivos virtuales en la Educación Superior. La investigación también pone especial relieve en la aparición de nuevas, desconocidas y transcendentes problemáticas derivadas del M-learning, como son las adicciones y las interferencias en el aula, que afectan sobre todo a los jóvenes estudiantes. Finalmente, nuestro estudio sugiere que la formación de los docentes podría recoger estas propuestas tecnológicas e incluirlas en sus estrategias. De hecho, sería preciso invertir el proceso, siendo la iniciativa educativa la que diseñe y genere específicamente pautas innovadoras en la gestión de estas formas y contenidos.Ministry of Economy and Competitiveness, Spain (Award: EDU2015-70491-R

T-Cell Development in Early Partially Decapitated Chicken Embryos

We have evaluated the immunohistological and cytofluorometric changes that occur in the thymus of chicken embryos partially decapitated at 33-38 hr of incubation (DCx embryos) in an attempt to analyze possible neuroendocrinological influences on T-cell differentiation and, indirectly, the ontogeny of the so-called neuroendocrine-immune network. The thymus of DCx embryos shows important variations that profoundly and selectively affect different T-cell subsets, but not the nonlymphoid cell components of thymic stroma. These modifications include the accumulation of cell precursors, mainly DN (CD4- CD8-) cells and immature CD8high CD4- cells, which expand but do not differentiate, resulting in an extreme decline of both DP (CD4+ CD8+) cells and TcR c-expressing cells. Accordingly, both subcapsulary and outer cortex increase in size, whereas the deep cortex and principally the thymic medulla almost disappear in DCx embryos. In contrast, other T-cell subsets of DCx embryos, largely CDgglowCD4- cells and TcR γδ-expressing cells do not undergo significant variations throughout thymic ontogeny

RapA2 is a calcium-binding lectin composed of two highly conserved cadherin-like domains that specifically recognize Rhizobium leguminosarum acidic exopolysaccharides

In silico analyses have revealed a conserved protein domain (CHDL) widely present in bacteria that has significant structural similarity to eukaryotic cadherins. A CHDL domain was shown to be present in RapA, a protein that is involved in autoaggregation of Rhizobium cells, biofilm formation, and adhesion to plant roots as shown by us and others. Structural similarity to cadherins suggested calcium-dependent oligomerization of CHDL domains as a mechanistic basis for RapA action. Here we show by circular dichroism spectroscopy, light scattering, isothermal titration calorimetry, and other methods that RapA2 from Rhizobium leguminosarum indeed exhibits a cadherin-like β-sheet conformation and that its proper folding and stability are dependent on the binding of one calcium ion per protein molecule. By further in silico analysis we also reveal that RapA2 consists of two CHDL domains and expand the range of CHDL-containing proteins in bacteria and archaea. However, light scattering assays at various concentrations of added calcium revealed that RapA2 formed neither homo-oligomers nor hetero-oligomers with RapB (a distinct CHDL protein), indicating that RapA2 does not mediate cellular interactions through a cadherin-like mechanism. Instead, we demonstrate that RapA2 interacts specifically with the acidic exopolysaccharides (EPSs) produced by R. leguminosarum in a calcium-dependent manner, sustaining a role of these proteins in the development of the biofilm matrix made of EPS. Because EPS binding by RapA2 can only be attributed to its two CHDL domains, we propose that RapA2 is a calcium-dependent lectin and that CHDL domains in various bacterial and archaeal proteins confer carbohydrate binding activity to these proteins.Fil: Abdian, Patricia Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Caramelo, Julio Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; ArgentinaFil: Ausmees, Nora. Lund University; SueciaFil: Zorreguieta, Angeles. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; Argentin

The Wound-Healing Portal Hypertensive Response

Portal hypertensive inflammation is associated with chronic liver diseases. The three successive and overlapping systemic inflammatory phenotypes, i.e., neurogenic, immune, and endocrine, which characterize the wound-healing response, are expressed by the portal venous system upon liver injury. The diverse functions of hepatic stellate cells in homeostasis and inflammation indicate the versatile nature of these mesenchymal-derived cells, which could adopt numerous phenotypes according to the interstitial microenvironmental characteristics. Consequently, these inflammatory phenotypes could represent the reexpression of two extra-embryonic functional axis, i.e., coelomic-amniotic and trophoblastic-vitelline, whose coupling in the portal system would induce a gastrulation-related phenotype. Therefore, hepatic stellate cells and liver-specific mesenchymal cells could recapitulate and couple these abovementioned extra-embryonic phenotypes during portal hypertension. These hepatic cellular population, thanks to their potential ability to integrate and reexpress functions showing analogies to extra-embryonic functions, display characteristics of stem/progenitor cells. In this way, during the development of portal hypertension, hepatic stellate cells not only could reexpress extra-embryonic functions, but also could adapt themselves in order to induce a gastrulation-related process in the space of Disse. Hence, by understanding the ontogenic interactions between hepatic stellate cells and the host inflammatory response in portal hypertension, it is possible to design effective therapeutic and prophylactic strategies to avoid or reverse wound-like hypertensive response

A novel concept for analysis and performance evaluation of wheeled rovers

[Abstract] - The analysis, design, and operation planning of rovers are often based on predictive dynamic simulation, where the multibody model of the vehicle is combined with terramechanics relations for the representation of the wheel–ground interaction. There are, however, limitations in terramechanics models that prevent their use in parametric analysis and simulation studies. Increasing mobility is generally a primary objective for the design and operation of rovers. The models and assumptions used in the analysis phase should target this objective. In this paper we put forward a new concept for the analysis of wheeled rovers, particularly for applications in off-road environments on soft soil. We propose a novel view of the problem based on the development of models that are primarily intended to represent how parameter changes in the robot design can influence performance. These models allow for the definition of indicators, which gives information about the behavior of the system. We term such models observative. In the reported work, a set of indicators for rover performance is formulated using such models. The ability of these indicators to characterize the behavior of a rover is assessed with a series of simulation tests and experiments. The indicators defined using observative models succeeded to capture the changes in rover performance due to variations in the system parameters. Results show that the proposed models can provide a useful tool for the design and operation of planetary exploration rovers

Anteproyecto de diseño de una urbanización en el sector este del Municipio de Managua, Comarca Las Cuarezmas

Para la elaboración de este trabajo, se utilizaron todas las herramientas adquiridas en los 5 años de la carrera de Arquitectura. Además se aplicaron algunos programas de computación, como son Prezi (Presentación de la defensa), Artlantis y el AAA logo (edición de imágenes y logos), las cuales no se imparten en la carrera de arquitectura de la UNAN-Managua El primer capítulo de esta investigación, contiene el marco de conceptualización, en el que se desarrolló un intensivo trabajo, de búsqueda y recolección bibliográfica relativa al tema de investigación, la cual sirvió de guía para el diseño de la urbanizadora. Entre las teóricas que aplican al tema están las siguientes: definiciones, estructura funcional de las urbanizaciones, normativas referentes a urbanizaciones, análisis de modelos análogos, nacionales como internacionales. El estudio de los modelos análogos nacionales e internacionales tales como el Residencial Montecielo y Residencial El Sauce, permitió establecer las bases de conocimiento necesarias para el diseño óptimo de una urbanización en la comarca las Comarca Las Cuarezmas relacionados a los sistemas constructivos utilizados, las soluciones funcionales al igual que identificar los errores cometidos en el diseño, las cuales fueron aprovechados para presentar estrategias de diseño de viviendas mínimas, con la infraestructura y equipamiento adecuado. El segundo capítulo del trabajo, consiste en un diagnóstico del sitio, en la cual nos brindará diferentes datos que nos permitirá saber si el terreno es factible para la construcción de una urbanización en la Comarca las Cuarezmas. Sin embargo en dicho diagnóstico, se toman en cuenta las normas y reglamentos, las cuales sirvieron de guía para el diseño de nuestra urbanización. Estas normativas ayudaron a reducir el riesgo contra los fenómenos naturales como terremotos, inundaciones, fallas del suelo, actividad volcánica, entre otros factores. Finalmente en el tercer capítulo se establecen los criterios de distribución, la configuración arquitectónica de cada uno de los modelos de viviendas en función del programa de necesidades y el programa arquitectónico definido, dando como resultado una propuesta de urbanización para la comarca Las Cuarezma

Energy reserves mobilization: Strategies of three decapod species

In food deprivation assays, several different responses have been observed in crustaceans. However, studying energy reserves utilization among more than one species during the same starvation period has not yet been performed, particularly to discern whether the responses are due to intrinsic and/or environmental factors. We hypothesize that decapod species with similar feeding habits have the same strategies in the use of energetic reserves during starvation, even though they inhabit different environments. The aim of this study was to compare the energy reserves mobilization of three decapods species (Cherax quadricarinatus, Palaemon argentinus and Munida gregaria) with similar feeding habits, exposed to similar food deprivation conditions. The crayfish, shrimp and squat-lobster were experimentally kept at continuous feeding or continuous starvation throughout 15 days. Every 3rd day, the midgut gland index (MGI), and the glycogen, lipid and protein contents were measured in the midgut gland (MG) and pleon muscle. Palaemon argentinus mobilized more reserves during starvation, followed by C. quadricarinatus, and the last M. gregaria. The starved shrimps presented low MGI, whereas MG showed a reduction in glycogen (from day 6 to 15), lipid (from day 3 to 15), and protein levels (at day 9 and 15) while in their muscle, lipid reserves decreased at days 3 and 6. In C. quadricarinatus, the most affected parameters in the MG were MGI, glycogen (from day 6 to 15), and lipids (at day 12 and 15). In the MG of M. gregaria only the glycogen was reduced during fasting from 3 to 15 days. Even though the three studied species have similar feeding habitats, we found that their energetic profile utilization is different and it could be explained by the habitat, life span, temperature, organ/tissue, and metabolism of the species. Our results may be useful to understand the several different responses of crustaceans during starvation.Fil: Sacristán, Hernán Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Rodriguez, Yamila Eliana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Pereira, Nair de Los Angeles. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Lopez, Laura Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Lovrich, Gustavo Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Fernandez Gimenez, Analia Veronica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentin

Mobility Evaluation of Wheeled Robots on Soft Terrain: Effect of Internal Force Distribution

[Abstract] Many applications of wheeled robots include operations in unstructured environments. Optimizing vehicle mobility is of key importance in these cases. Reduced mobility can limit the ability of the robot to achieve the mission goals and can even render it immobile in extreme cases. In this paper, some aspects of the effect of the wheel–ground interaction force distribution on mobility are investigated. A performance index based on the normal force distribution is used to compare different design layouts and vehicle configurations. The validity of this index was assessed using both multibody dynamics simulation and experimental results obtained with a six-wheeled rover prototype. Results confirmed that modifying the system configuration and employing active suspensions to alter the normal force distribution can lead to an increase of traction force available at the wheel–terrain interfaces, thus improving rover mobility. Finally, the study was extended to consider the change of soil properties during operation due to the multipass effect. Optimum load distributions were obtained as the solution of a constrained maximization problem.MINECO; JCI-2012-1237