Circovirus porcino: un virus pequeño que genera un gran problema

Porcine circoviruses type 1 and type 2 (PCV-1 and PCV-2) are very small (17 nm), nonenveloped, icosahedral viruses (Tisher y col., 1982), with circular, single stranded DNA genomes of approximately 1,700 nucleotides length, encoding 2 major ambisense open reading frames (Mankertz y col., 1998; Hamel y col., 1998). Together with a number of avian viruses with similar molecular characteristics, the porcine circoviruses are classified in the genus Circovirus within the family Circoviridae. Although PCV-1 persists in the pig population, the presence of PCV-1 has not been associated with any recognised clinical signs or pathology. In contrast, PCV-2 has been implicated as the mayor causative agent of Postweaning Multisystemic Wasting Syndrome (PMWS). It is characterized mainly by loose of weight, general wasting, and severe immunosuppressive effects with premature death of piglets. PCV-2 effects are generated by inhibition of plasmacytoid dendritic cells (pdc) so called natural interferon-α producing cells (NIPCs) unlinking the innate and acquired immune systems, and renderinga host susceptible to secondary or concomitant microbial infections. Therefore, PCV-2 additionally is associated with other porcine diseases and syndromes, such as reproductive failure, respiratory disease complex, congenital tremor, porcine dermatitis and nephropathy syndrome, nectrotizing tracheitis and exudative epidermitis, together with other viral and bacterial agents, including Parvovirus, PRRSV (Porcine Reproductive and Respiratory Syndrome virus), Influenza, Aujeszky and Mycoplasma pneumoniae, Actinobacillus pleuropneumoniae, Streptococcus suis and Pastereulla multocida. Nowadays, these diseases are known as PCVAD or PCV-2-associated diseases, in order to group all the diseases attributed to porcine circovirus type 2. The PCV-2-associated diseases, mainly PMWS, at present are considered to be the greatest economic problem associated with the pig industry world-wide

Diseño de un modelo de estimación de costos eficientes para explotaciones ganaderas de pequeños productores crianceros ubicados entre las regiones del Maule y de los Lagos

The sanitary and commercial advantages of Chile have given the only opportunity for the development of stockbreeding bovine, transforming it in a new opportunity is strongly presented for the small breeding producers of our country, since that they are who initiate the productive cycle of bovine meat.The challenge for them is based on increasing their stock breeder mass, in volume and quality, for this reason, they obligatory need to be more efficient in their costs. The objective of this investigation was the designing of an efficient evaluation cost model for the stock breeder exploitation of the small producersof our country. The real productive costs, associated to the system of breeding, were determined through a survey applied to the small stockbreeder producers from the VII to the X regions. Besides, the relevant variables that influence in cost of production of system of breeding and mathematics expressions used forquantify these variables, were determined. For determining the better productive practices it was applied the technique of data evolvement analysis, by means of which the efficient producers were identified. The model of evaluation costs was based on the concept of comparative efficiency or benchmarking, by meansof which, an efficient system of breeding that incorporated the best productive practices and technical characteristics of the most efficient producers, was designed.Las ventajas de tipo sanitario y comercial de Chile han dado una oportunidad única para el desarrollo de la ganadería bovina, transformándola en un nuevo polo exportador. Esta nueva oportunidad se presenta fuertemente para los pequeños productores crianceros de nuestro país, ya que son ellos los que inician el ciclo productivo de la carne bovina. El desafío para ellos está en aumentar su masa ganadera en volumen y calidad para lo cual necesitan obligatoriamente ser cada vez más eficientes en sus costos. El objetivo de esta investigación fue diseñar un modelo de estimación de costos eficientes para explotaciones ganaderas de los pequeños productores crianceros de nuestro país. Se determinaron los costos productivos reales asociados al sistema de crianza a través de una encuesta que se aplicó a pequeños productores crianceros desde la VII a la X regiones. Se determinaron además las variables relevantes que influyen en los costos de producción del sistema de crianza y las expresiones matemáticas utilizadas para cuantificar estas variables. Para determinar las mejores prácticas productivas se aplicó la técnica del Análisis Envolvente de Datos (DEA), con la cual   se identificaron los productores eficientes. El modelo de estimación de costos se basó en el concepto de eficiencia comparativa o benchmarking, por lo que se diseñó un sistema decrianza modelo o eficiente que incorpora las mejores prácticas productivas y las características técnicas de los productores más eficientes

Origin of hotsprings near Villarrica volcano

Trabajo para optar al grado de Magíster en Recursos NaturalesEl volcán Villarrica es uno de los volcanes más activos de la Zona Volcánica de Los Andes del Sur (SAVZ) y presenta varias manifestaciones termales en sus alrededores. Si bien existen numerosos estudios acerca de la composición y origen de las aguas termales de esta zona, no se ha podido establecer cuál es la influencia de la actividad volcánica en estas manifestaciones. La mayoría de las termas ubicadas cerca de la zona volcánica, entre las ciudades de Pucón y Curarrehue, fueron muestreadas entre los años 2012 y 2017. En este estudio, identificamos los procesos que afectan la composición de las aguas y que puedan explicar el origen y su naturaleza. Análisis químicos fueron realizados permanentemente, con el objetivo de describir la composición química de las aguas termales, y con esta información entender el comportamiento de las aguas en profundidad. Así mismo, se implementó por primera vez en esta zona de estudio, el análisis de gas disuelto en agua. Estas manifestaciones emergen directamente desde granitoides, depósitos volcanoclásticos, piroclásticos y fluviales. Los parámetros fisicoquímicos tales como: temperatura, pH y sólidos disueltos totales (TDS) fueron medidos in-situ. Nuestros resultados muestran que las temperaturas en un rango entre 29 y 87ºC son comunes en estas aguas mesotermales y los valores de pH permiten clasificar estos fluidos como neutros – alcalinos (pH=7.0 – 9.7). Las manifestaciones presentan concentraciones de iones en rangos bajos y moderados (TDS=76 – 656 mg/L). Las aguas y los gases disueltos fueron muestreados para analizar elementos mayores, trazas e isótopos (18O-D). Con estos datos, se observó una mezcla de procesos en los cuales las recargas meteóricas del sistema y su interacción en profundidad con gases magmáticos, son los principales mecanismos de generación de la termalidad de esta zonaThe Villarrica volcano is one of the most active volcanoes of the Southern Andes Volcanic Zone (SAVZ) and has several thermal manifestations in their surroundings. Although there are numerous studies about the composition and origin of the thermal waters of this area, it has not been possible to establish which is the influence of volcanic activity in these manifestations. Most hotsprings located close to the Villarrica volcano, between Pucón and Curarrehue locations were sampled during 2012 and 2016. In this study, we identify the processes that affect the composition of the water that can explain the origin and its nature.Chemical analyzes were carried out permanently, with the objective of describing the chemical composition of the thermal waters, and with this information to understand the behavior of the waters in depth. Likewise, the analysis of gases dissolved in water was implemented for the first time in this area of study. This manifestation emerges directly from granitoides, volcanoclastic, pyroclastic and fluvial deposits. Physicochemical parameters such as: temperature, pH, and total dissolved solids (TDS) were measured in-situ. Our results showed that temperatures ranging between 29 – 87 °C, are common in these mesothermal waters, and pH allows to classify these fluids as neutral to alkaline waters (pH=7.0 to 9.7). Hot springs present low to moderate concentrations of ions (TDS= 76 to 656 mg/L). Water and dissolved gases were sampled to analyze main elements, traces and isotopes (18O – D). With these data, a mixture of processes was observed in which the meteoric recharges of the system and their deep interaction with magmatic gases are the main mechanisms of generation of the thermal manifestations of this zon

Discussion of Fairness and Implementability in Stackelberg Security Games

International audienceIn this article we discuss the impact of fairness constraints in Stackelberg Security Games. Fairness constraints can be used to avoid discrimination at the moment of implementing police patrolling. We present two ways of modelling fairness constraints, one with a detailed description of the population and the other with labels. We discuss the implementability of these constraints. In the case that the constraints are not implementable we present models to retrieve pure strategies in a way that they are the closest in average to the set of fairness constraints

{\lambda}-Cent-Dians and Generalized-Center for Network Design

In this paper, we extend the notions of $\lambda$-cent-dian and generalized-center from Facility Location Theory to the more intricate domain of Network Design. Our focus is on the task of designing a sub-network within a given underlying network while adhering to a budget constraint. This sub-network is intended to efficiently serve a collection of origin/destination pairs of demand. % rather than individual points. The $\lambda$-cent-dian problem studies the balance between efficiency and equity. We investigate the properties of the $\lambda$-cent-dian and generalized-center solution networks under the lens of equity, efficiency, and Pareto-optimality. We provide a mathematical formulation for $\lambda\geq 0$ and discuss the bilevel structure of this problem for $\lambda>1$. Furthermore, we describe a procedure to obtain a complete parametrization of the Pareto-optimality set based on solving two mixed integer linear formulations by introducing the concept of maximum $\lambda$-cent-dian. We evaluate the quality of the different solution concepts using some inequality measures. Finally, for $\lambda\in[0,1]$, we study the implementation of a Benders decomposition method to solve it at scale

An exact dynamic programming approach to segmented isotonic regression

This paper proposes a polynomial-time algorithm to construct the monotone stepwise curve that minimizes the sum of squared errors with respect to a given cloud of data points. The fitted curve is also constrained on the maximum number of steps it can be composed of and on the minimum step length. Our algorithm relies on dynamic programming and is built on the basis that said curve-fitting task can be tackled as a shortest-path type of problem. Numerical results on synthetic and realistic data sets reveal that our algorithm is able to provide the globally optimal monotone stepwise curve fit for samples with thousands of data points in less than a few hours. Furthermore, the algorithm gives a certificate on the optimality gap of any incumbent solution it generates. From a practical standpoint, this piece of research is motivated by the roll-out of smart grids and the increasing role played by the small flexible consumption of electricity in the large-scale integration of renewable energy sources into current power systems. Within this context, our algorithm constitutes an useful tool to generate bidding curves for a pool of small flexible consumers to partake in wholesale electricity markets.This research has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement no. 755705). This work was also supported in part by the Spanish Ministry of Economy, Industry and Competitiveness and the European Regional Development Fund (ERDF) through project ENE2017-83775-P. Martine Labbé has been partially supported by the Fonds de la Recherche Scientifique - FNRS under Grant(s) no PDR T0098.18

Contrastive Losses and Solution Caching for Predict-and-Optimize

Many decision-making processes involve solving a combinatorial optimization problem with uncertain input that can be estimated from historic data. Recently, problems in this class have been successfully addressed via end-to-end learning approaches, which rely on solving one optimization problem for each training instance at every epoch. In this context, we provide two distinct contributions. First, we use a Noise Contrastive approach to motivate a family of surrogate loss functions, based on viewing non-optimal solutions as negative examples. Second, we address a major bottleneck of all predict-and-optimize approaches, i.e. the need to frequently recompute optimal solutions at training time. This is done via a solver-agnostic solution caching scheme, and by replacing optimization calls with a lookup in the solution cache. The method is formally based on an inner approximation of the feasible space and, combined with a cache lookup strategy, provides a controllable trade-off between training time and accuracy of the loss approximation. We empirically show that even a very slow growth rate is enough to match the quality of state-of-the-art methods, at a fraction of the computational cost.Comment: Accepted at IJCAI202