Tipología y caracterización de cunicultores en los Estados del centro de México

This study aimed to identify and characterize the type of rabbit farmers in Mexico's central states based on social, productive, technological, economic, and efficiency factors; this information could help outline recommendations that support cuniculture practices. A survey was designed and applied to 155 rabbit production units (RPU) to obtain information about their socioeconomic, productive, and economic status; this survey also evaluated their use of facilities and technological components. Fourteen original variables were defined and helped stratify rabbit farmers through multivariate methods. The resulting groups were characterized and compared by analyzing variance following a completely randomized model for the continuous variables and a test of homogeneity for the categorical variables. Four factors accounted for 67.5 % of the total variation. Due to the factor loadings of the analyzed variables, these factors were identified as 1) productive capacity of the RPU, 2) technical capacity of the RPU, 3) farmer's capacity, and 4) technical efficiency of the RPU. Three types of producers were identified: small-scale family rabbit farmer (37 %), medium-scale family rabbit farmer (50 %), and business rabbit farmer (13 %). This typology could contribute to the outline of cuniculture-specific public policies to increase the efficiency and productivity of RPU in Mexico's central states.El objetivo fue identificar y caracterizar el tipo de productores de conejos en los estados del centro de México con base a factores sociales, productivos, tecnológicos, económicos y de eficiencia, con el fin de generar información para el diseño de recomendaciones de apoyo a la cunicultura. Se diseñó y aplicó un cuestionario a una muestra de 155 unidades de producción de conejos (UPC) de donde se obtuvo información socioeconómica, productiva, económica, uso de infraestructura y de componentes tecnológicos, de la cual se definieron 14 variables originales, con las que se obtuvo la estratificación de los cunicultores aplicando métodos multivariados. Para la caracterización y comparación de los grupos resultantes se realizó un análisis de varianza bajo un modelo completamente aleatorio para las variables continuas y una prueba de homogeneidad para las variables categóricas. Se detectaron cuatro factores que explican el 67.5 % de la variación total y que por las cargas factoriales de las variables analizadas se llamaron: 1) capacidad productiva de la UPC, 2) capacidad técnica de la UPC, 3) capacidades del cunicultor y 4) eficiencia técnica de la UPC. Se identificaron tres tipos de productores; pequeño cunicultor familiar (37 %), mediano cunicultor familiar (50 %) y cunicultor empresarial (13 %). La tipología obtenida puede ser útil para contribuir al diseño de políticas públicas diferenciadas de apoyo a la cunicultura, que incidan en una mayor eficiencia y productividad de unidades de producción de conejos en los estados del centro del país

Instalación eléctrica de un complejo de naves industriales

El presente proyecto trata de las instalaciones de un edificio destinado a naves industriales con vistas a su alquiler en un futuro como naves destinadas a almacenaje, dado esto se realizarán las instalaciones pensando en que dichas naves serán alquiladas por empresas dedicadas a depósitos y almacenajes. Las instalaciones a realizar serán las dedicadas a la media tensión (centro de transformación que dará servicio a las cuatro naves industriales, la referente a la instalación eléctrica de las naves dotándolas de alumbrado y tomas de corriente, la referente a la protección contra incendios dotando a las naves con bocas de incendio equipadas y sistemas de detección de incendios

Transformer modelling considering power losses using an inverse Jiles-Atherton approach

Power transformers are devices with non-linear behavior due to the saturation of the ferromagnetic core. When modelling such devices, the saturation effect must be taken into account because it greatly affects their performance and efficiency. In this paper, an electromagnetic model for power transformers is proposed and experimentally validated using an electrical T-model coupled with a reluctance network to model the magnetic part. The electrical circuit and the reluctance network are linked by two B–H approaches. The B–H relationships are modelled by the full hysteresis cycle based on the inverse Jiles-Atherton theory and by the initial magnetization curve. The results obtained with the inverse Jiles-Atherton theory model reproduce the magnetic core behavior with more accuracy than the one based on the initial magnetization curve, especially at low load conditions where saturation plays a more prominent role on the no-load current. The proposed model can be applied to other magnetic devices such as inductors for power electronic applications or electromechanical relays, among others.Peer ReviewedPostprint (published version

A multi-objective GA to demand-side management in an automated warehouse

The simultaneous operation of the automated storage and retrieval machines (ASRs) in an automated warehouse can increase the likelihood that high power demand peaks turn unstable the electric system. Furthermore, high power peaks mean the need for more electrical power contracted, which in turns leads to more fixed operation cost and inefficient use of the electrical installations. In this context, we present a multi-objective genetic algorithm approach (MOGA) to implement demand-side management (DSM) in an automated warehouse. It works minimizing the total energy demand, but without increasing substantially the time for the operation. Simulations show the performances of the new approach.Peer ReviewedPostprint (published version

Detection of eccentricity faults in five-phase ferrite-PM assisted synchronous reluctance machines

Air gap eccentricity faults in five-phase ferrite-assisted synchronous reluctance motors (fPMa-SynRMs) tend to distort the magnetic flux in the air gap, which in turn affects the spectral content of both the stator currents and the ZSVC (zero-sequence voltage component). However, there is a lack of research works dealing with the topic of fault diagnosis in multi-phase PMa-SynRMs, and in particular, focused to detect eccentricity faults. The analysis of the spectral components of the line currents and the ZSVC, allows developing fault diagnosis algorithms to detect eccentricity faults. The effect of the operating conditions is also analyzed, since this paper shows that it has a non-negligible impact on the effectivity and sensitivity of the diagnosis based on the analysis of the stator currents and the ZSVC. To this end, different operating conditions are analyzed. The paper also evaluates the influence of the operating conditions on the harmonic content of the line currents and the ZSVC, and determines the most suitable operating conditions to enhance the sensitivity of the analyzed methods. Finally, fault indicators to detect eccentricity faults, which are based on the spectral content of the stator currents and the ZSVC are derived, and their performance is assessed. The approach presented in this work may be useful to develop fault diagnosis strategies based on the acquisition and subsequent analysis and interpretation of the spectral content of the line currents and the ZSVC.Peer ReviewedPostprint (published version

Compreender crianças com inibição emocional: Uma abordagem com múltiplos informadores do contexto educacional e familiar

Behavioral inhibition (BI) is a temperament trait characterized by extreme fear in the face of novelty. BI has been associated with the development of mental disorders. However, there is a lack of research examining the socioemotional and behavioral characteristics of behaviorally inhibited children both in family and school settings. For a more comprehensive and in-depth overview of children’s behavior in each of these contexts, this study has collected data from both parents (mother and father – family setting) and from teachers (educational environment). The sample consisted of 109 children aged between four and six years old. Multi-informant approach was used: all fathers, mothers and teachers completed both the Preschool Behavioral Inhibition Scales, the Child Behavior Checklist for parents and teachers, and the Behavior Assessment System for Children and Adolescents. Our findings revealed that children classified as BI exhibit less socioemotional and behavioral adjustments than their uninhibited peers both in family and school contexts. Further, the shyness variable seemed to be strongly associated with behavioral inhibition, regardless of informant and context.A inibição comportamental (IC) é um traço de temperamento caracterizado por medo extremo face a situações novas. A IC tem sido associada ao desenvolvimento de perturbações mentais. No entanto, é escassa a investigação que examina as características socio-emocionais e comportamentais de crianças com inibição comportamental em contextos educacionais e familiares. Para uma visão global mais compreensiva e aprofundada do comportamento da criança em cada um destes contextos, este estudo recolheu dados com os pais (mãe e pai – contexto familiar) e com os professores (contexto educacional). A amostra foi constituída por 109 crianças, entre os quatro e os seis anos de idade. Foi utilizada uma abordagem com múltiplos informadores: todos os pais, mães e professores completaram as Escalas de Inibição Comportamental para o Pré-Escolar, o Questionário de Comportamento da Criança para pais e professores (CBCL e TRF), e o Sistema de Avaliação do Comportamento para Crianças e Adolescentes (BASC). Os resultados revelaram que crianças consideradas com IC apresentavam níveis mais baixos de ajustamento socio-emocional e comportamental comparativamente a crianças não inibidas, tanto no contexto familiar como no contexto educacional. Adicionalmente, a variável de timidez pareceu ser a que mais fortemente se associou à inibição comportamental, independentemente do informador e do contexto

Closed-loop controller for eliminating the contact bounce in DC core contactors

The undesirable phenomenon of the contact bounce causes severe erosion of the contacts and, as a consequence, their electrical life and reliability are greatly reduced. On the other hand, the bounce of the armature can provoke re-opening of the contacts, even when they have already been closed. This paper deals with the elimination of the bounce in both contacts and armature of a commercial dc core contactor. This is achieved by means of a current closed-loop controller, which only uses as input the current and voltage of the contactor’s magnetizing coil. The logic control has been implemented in a low cost microcontroller. Moreover, the board control can be fed by either dc or ac, and either in 50 Hz or 60 Hz so as to extend its applicability. A set of data is obtained from the measurement of the position and velocity of the movable parts for different operating voltages, and the dynamic behavior of the contactor is discussed.Peer ReviewedPostprint (published version

Reformulating Pro-Oxidant Microglia in Neurodegeneration

In neurodegenerative diseases, microglia-mediated neuroinflammation and oxidative stress are central events. Recent genome-wide transcriptomic analyses of microglial cells under different disease conditions have uncovered a new subpopulation named disease-associated microglia (DAM). These studies have challenged the classical view of the microglia polarization state's proinflammatory M1 (classical activation) and immunosuppressive M2 (alternative activation). Molecular signatures of DAM and proinflammatory microglia (highly pro-oxidant) have shown clear differences, yet a partial overlapping gene profile is evident between both phenotypes. The switch activation of homeostatic microglia into reactive microglia relies on the selective activation of key surface receptors involved in the maintenance of brain homeostasis (a.k.a. pattern recognition receptors, PRRs). Two relevant PRRs are toll-like receptors (TLRs) and triggering receptors expressed on myeloid cells-2 (TREM2), whose selective activation is believed to generate either a proinflammatory or a DAM phenotype, respectively. However, the recent identification of endogenous disease-related ligands, which bind to and activate both TLRs and TREM2, anticipates the existence of rather complex microglia responses. Examples of potential endogenous dual ligands include amyloid β, galectin-3, and apolipoprotein E. These pleiotropic ligands induce a microglia polarization that is more complicated than initially expected, suggesting the possibility that different microglia subtypes may coexist. This review highlights the main microglia polarization states under disease conditions and their leading role orchestrating oxidative stress

Divergent Effects of Metformin on an Inflammatory Model of Parkinson’s Disease

The oral antidiabetic drug metformin is known to exhibit anti-inflammatory properties through activation of AMP kinase, thus protecting various brain tissues as cortical neurons, for example. However, the effect of metformin on the substantia nigra (SN), the main structure affected in Parkinson’s disease (PD), has not yet been studied in depth. Inflammation is a key feature of PD and it may play a central role in the neurodegeneration that takes place in this disorder. The aim of this work was to determine the effect of metformin on the microglial activation of the SN of rats using the animal model of PD based on the injection of the pro-inflammogen lipopolysaccharide (LPS). In vivo and in vitro experiments were conducted to study the activation of microglia at both the cellular and molecular levels. Our results indicate that metformin overall inhibits microglia activation measured by OX-6 (MHCII marker), IKKβ (pro-inflammatory marker) and arginase (anti-inflammatory marker) immunoreactivity. In addition, qPCR experiments reveal that metformin treatment minimizes the expression levels of several pro- and anti-inflammatory cytokines. Mechanistically, the drug decreases the phosphorylated forms of mitogen-activated protein kinases (MAPKs) as well as ROS generation through the inhibition of the NADPH oxidase enzyme. However, metformin treatment fails to protect the dopaminergic neurons of SN in response to intranigral LPS. These findings suggest that metformin could have both beneficial and harmful pharmacological effects and raise the question about the potential use of metformin for the prevention and treatment of PD.España MINECO SAF2015-64171-

Structural and Technological Characterization of Tropical Smallholder Farms of Dual-Purpose Cattle in Mexico

Dual-purpose cattle smallholder farms (DP) exhibit a critical economic situation. The objective of this research was building a typology for DP in tropical conditions and characterizing them technologically. This will help developing more effective public policies in DP farms located in tropical conditions. A sample of 1.475 farms located in the tropical area of Mexico was selected. The typology was built using multiple correspondence analysis (MCA). Subsequently, five groups were identified by a hierarchical cluster analysis with Ward’s method. Groups 1 and 2, covered a 46.5% of the farms; these ones presented a small-scale productive model with low levels of technological adoption, improvements were mainly associated to the area of reproduction and genetics. Very small farms (Group 3) showed orientation to subsistence. They need to improve all the technological areas. Groups 4 and 5 (29.4% of the sample) were the biggest and more specialized farms. Group four farms were located in dry tropics and showed the highest levels of technological adoption in the areas of reproduction, management, and feeding. These farms require improvement in the areas of reproduction, animal health, and feeding. Group 5 farms were located in the wet tropics and showed specialization in reproduction, genetics, and animal health areas. In this last group, it is necessary to improve management and feeding areas