Short-term variability of comet C/2012 S1 (ISON) at 4.8 AU from the Sun

We observed comet C/2012 S1 (ISON) during six nights in February 2013 when it was at 4.8 AU from the sun. At this distance and time the comet was not very active and it was theoretically possible to detect photometric variations likely due to the rotation of the cometary nucleus. The goal of this work is to obtain differential photometry of the comet inner coma using different aperture radii in order to derive a possible rotational period. Large field of view images were obtained with a 4k x 4k CCD at the f/3 0.77m telescope of La Hita Observatory in Spain. Aperture photometry was performed in order to get relative magnitude variation versus time. Using calibrated star fields we also obtained ISON's R-magnitudes versus time. We applied a Lomb-Scargle periodogram analysis to get possible periodicities for the observed brightness variations, directly related with the rotation of the cometary nucleus. The comet light curve obtained is very shallow, with a peak-to-peak amplitude of 0.03 $\pm$ 0.02 mag. A tentative synodic rotational period (single-peaked) of 14.4 $\pm$ 1.2 hours for ISON's nucleus is obtained from our analysis, but there are other possibilities. We studied the possible effect of the seeing variations in the obtained periodicities during the same night, and from night to night. These seeing variations had no effect on the derived periodicity. We discuss and interpret all possible solutions for the rotational period of ISON's nucleus.Comment: 15 pages, 3 Figures, 2 Tables, accepted for publication in A&

The role of relative abundance and identity in the effectiveness of generalist predators as biocontrol agents of Pieris rapae L. (Lepidoptera: Pieridae)

The importance of generalist arthropod predator assemblages in suppressing pests has recently received more attention. However, few studies have investigated the impacts of assemblage structure on pest mortality. This study assessed the influence of relative abundance and taxonomic identity among an assemblage of generalist predators in collards, (Brassica oleracea var. acephala), on the mortality of Pieris rapae. In field surveys and laboratory assays, I determined that Coleomegilla maculata was the numerically dominant while Coccinella septempunctata and Podisus maculiventris were numerically subdominant predators of P. rapae larvae. Experimental mesocosms were used to determine whether numerically dominant predators alone, regardless of taxonomic identity, imposed greater P. rapae larval mortality than when in an assemblage. As numerically dominant species, only C. septempunctata imposed greater P. rapae larval mortality alone than when in an assemblage. This research highlights the importance of considering both relative abundance and identity in studies involving predator assemblages and biocontrol

Energy Harvesting Potential of Terfenol-D for On-Board Bearing Health Monitoring Applications

One of the limiting factors in on-board bearing health monitoring systems is the life of the batteries used to power the system. Thus, any device that can extend the life of the battery, or entirely replace it, is a notable improvement on any currently available systems. Existing on-board monitoring systems, not optimized for low power, are designed to run on approximately 300 mW of power. Current bearing health monitoring systems have proven effective with as few as one reading every four minutes. The environment under which railroad bearings operate is a harsh one, making most forms of energy harvesting very hard to implement. Terfenol-D is a novel and sustainable solution for this problem due to its durable characteristics and strong magnetostriction. A fixture is designed using multiple magnets of ranging magnetization to properly characterize energy harvesting using Terfenol-D. The maximum available power observed during these experiments is about 77 mW under ideal conditions. The generated power is sufficient to run low-power bearing health monitoring systems

Service life estimation of heritage buildings: a case study

ARTICULO ESPECIALIZADO PUBLICADO EN REVISTA INTERNACIONAL INDEXADAThe goal of this document is to present a case study to estimate the service life of a heritage building in a quick and practical manner. The methodology is mainly a modification of the ISO 15686 factor method. The main result is a practical method to be used mainly by architects and restorers to produce residual service life estimations of historical buildings taking into consideration not only the 7 typical ISO durability factors, but also one more related to the degree and quality of redevelopments and reparations carried out on the building. It is concluded that it is a practical and versatile method to estimate not only the service life of historical buildings but also any sort of building for which remaining service life is needed and even to estimate architectural projects’ service life

Green building rating systems and their application in the Mexican context

Revista indexada en SCOPUSThis article offers a review of the scientific literature aimed at putting forward a proposal on the main variables or categories of sustainable design to take into consideration to manage, plan, design, build and maintain buildings in Mexico. The methodology consisted in reviewing 5 successfully tried international green building models (rating systems), from which a series of requirements by sustainable category were taken in order to propose categories and variables proper to the Mexican context. The result was a checklist that comprises sustainable design requirements broken down by categories: natural, human, technologic and economic to apply in the Mexican context. It is concluded that successfully tried green building international models such as: LEED®, BREAM®, CASBEE®, ESTIDAMA® or Green Star® can be very useful to manage, plan, design and construct sustainable buildings around the world

Methodological considerations when translating "burnout"

No study has systematically examined how researchers address cross-cultural adaptation of burnout. We conducted an integrative review to examine how researchers had adapted the instruments to the different contexts. We reviewed the Content Validity Indexing scores for the Maslach Burnout Inventory-Human Services Survey from the 12-country comparative nursing workforce study, RN4CAST. In the integrative review, multiple issues related to translation were found in existing studies. In the cross-cultural instrument analysis, 7 out of 22 items on the instrument received an extremely low kappa score. Investigators may need to employ more rigorous cross-cultural adaptation methods when attempting to measure burnout

Host-pathogen evolutionary signatures reveal dynamics and future invasions of vampire bat rabies

Anticipating how epidemics will spread across landscapes requires understanding host dispersal events that are notoriously difficult to measure. Here, we contrast host and virus genetic signatures to resolve the spatiotemporal dynamics underlying geographic expansions of vampire bat rabies virus (VBRV) in Peru. Phylogenetic analysis revealed recent viral spread between populations that, according to extreme geographic structure in maternally inherited host mitochondrial DNA, appeared completely isolated. In contrast, greater population connectivity in biparentally inherited nuclear microsatellites explained the historical limits of invasions, suggesting that dispersing male bats spread VBRV between genetically isolated female populations. Host nuclear DNA further indicated unanticipated gene flow through the Andes mountains connecting the VBRV-free Pacific coast to the VBRV-endemic Amazon rainforest. By combining Bayesian phylogeography with landscape resistance models, we projected invasion routes through northern Peru that were validated by real-time livestock rabies mortality data. The first outbreaks of VBRV on the Pacific coast of South America could occur by June 2020, which would have serious implications for agriculture, wildlife conservation, and human health. Our results show that combining host and pathogen genetic data can identify sex biases in pathogen spatial spread, which may be a widespread but underappreciated phenomenon, and demonstrate that genetic forecasting can aid preparedness for impending viral invasions

Análisis de inversiones en el Mercado de Criptoactivos, para minimizar el riesgo, en la rentabilidad de las inversiones financieras, de las grandes empresas del sector comercio, en el municipio de Santa Ana

El capital es la parte esencial que mueve a la empresa a su funcionamiento, es decir, es el recurso que permite a cualquier institución que pueda sobrevivir frente al mercado. Sin dinero, las empresas no pueden realizar inversiones de ningún tipo, y sin las inversiones no podría existir circulación del dinero, lo que afectaría la economía de cualquier país. Las empresas son los lugares donde se da la toma de decisiones de invertir o no invertir su capital; sino muestra una oportunidad de retorno, no es considerada como una buena alternativa de inversión, ya que puede llevar a una elevada perdid

Desarrollo de un sistema de inspección automático de PCB’S mediante visión artificial

El desarrollo del sistema de inspección automática de PCBs mediante visión artificial facilita, simplifica y evita problemas de cansancio, a las personas encargadas de realizar la inspección, de la empresa DINNOVASOFT. En la etapa inicial se implementa el hardware, que integra el sistema de adquisición a través de un sensor óptico (escáner), y para el procesamiento digital de imágenes se realiza a través de un ordenador; para el alojamiento y funcionamiento del hardware del sistema de adquisición, se ha construido una estructura metálica que contiene, un sistema de iluminación, encargado de intensificar el flujo lumínico sobre el área del PCB, un sistema que desplaza el PCB hacia la ventana del escáner, mediante el giro de un motor a pasos controlado por un Arduino, y por último un escáner encargado de la captura y digitalización de imagen del PCB; la siguiente etapa es el desarrollo del software, que se realiza en un PC, en lenguaje programación Python, OpenCV y PYQT5, el método es detectar el defecto en función de la imagen digital del PCB, utilizando tecnologías de procesamiento computacional de imágenes, el algoritmo se basa en la entrada de dos imágenes, una a ser examinada en busca de errores y la otra es la imagen de referencia sin errores, estas dos imágenes al compararse y mediante operaciones de sustracción, análisis, y reconocimiento, proporcionan como resultado los errores del PCB, finalmente estos defectos pueden ser visualizados por una interfaz gráfica.The development of the automatic inspection system for PCBs by means of artificial vision makes it easy, simplifies and avoids fatigue problems for the people in charge of carrying out the inspection, of the DINNOVASOFT company. In the initial stage, the hardware is implemented, which integrates the acquisition system through an optical sensor (scanner), and for the digital image processing it is carried out through a computer; For the housing and operation of the hardware of the acquisition system, a metallic structure has been built that contains, a lighting system, in charge of intensifying the light flux over the PCB area, a system that moves the PCB towards the scanner window, by turning a stepper motor controlled by an Arduino, and finally a scanner in charge of capturing and digitizing the PCB image; The next stage is the development of the software, which is carried out on a PC, in Python, OpenCV and PYQT5 programming language, the method is to detect the defect based on the digital image of the PCB, using computational image processing technologies, the algorithm is based on the input of two images, one to be examined for errors and the other is the reference image without errors, these two images when compared and through subtraction, analysis, and recognition operations, resulting in the errors of the PCB, finally these defects can be visualized by a graphical interface

Incidence of complications in breast reconstruction with autologous tissue in a third level hospital

Background: The objective of this study is to analyze the incidence of complications after breast reconstruction with pedicled or free flaps at the hospital general de Mexico "Dr. Eduardo Liceaga”. Methods: A retrospective, single-center study, including 44 female patients, who underwent immediate or delayed breast reconstruction after breast cancer, between 2019 and 2020, and had at least a 2-year follow up, evaluating the association between patient risk factors (age, history of radiotherapy, presence of overweight or obesity and immediate or delayed reconstruction) with the presence of complications such as seroma, hematoma, wound infection or wound dehiscence. We analyzed data with SPSS software, v23.0. Results: There was no statistically significant difference for the presence of complications associated with risk factors studied. Conclusions: We need more prospective, multicenter studies, including larger sample and strict follow up of patients