Small scale fracture behaviour of multilayer TiN/CrN systems: Assessment of bilayer thickness effects by means of ex-situ tests on FIB-milled micro-cantilevers

TiN/CrN multilayered PVD coatings are known to exhibit outstanding micromechanical properties and wear resistance. On the other hand, information on their small scale fracture behaviour is rather scarce. The present work aims to address it by testing to failure FIB-milled microbeams of multilayer TiN/CrN systems with different bilayer periods (8, 19 and 25 nm). In doing so, these micrometric specimens are first FIB notched, and thus deflected by means of a nanoindentation system. It is found that multilayer architecture translates into a beneficial synergic effect regarding critical load for reaching unstable failure; and thus, on energy absorption at fracture. Such behaviour is associated with small scale crack deflection as main toughening mechanism.Peer ReviewedPostprint (author's final draft

Product Recurrence for Weighted Backward Shifts

This is a pre-copy-editing, author-produced PDF of an article accepted for publication in Applied Mathematics & Information Sciences following peer review. The definitive publisher-authenticated version is available online at: http://www.naturalspublishing.com/ContIss.asp?IssID=293[EN] We study product recurrence properties for weighted backward shifts on sequence spaces. The backward shifts that have non-zero product recurrent points are characterized as Devaney chaotic shifts. We also give an example of weighted shift that admits points which are recurrent and distal, but not product recurrent, in contrast with the dynamics on compact sets. An example of a product recurrent point with unbounded orbit is also provided.This work is supported in part by MICINN and FEDER, Project MTM2013-47093-P, and by GVA, Project PROMETEOII/2013/013. We thank the referee whose report produced an improvement in the presentation of the paper.Galán, VJ.; Martínez Jiménez, F.; Oprocha, P.; Peris Manguillot, A. (2015). Product Recurrence for Weighted Backward Shifts. Applied Mathematics & Information Sciences. 9(5):2361-2365. https://doi.org/10.12785/amis/090518S236123659

Chemical source localization fusing concentration information in the presence of chemical background noise

We present the estimation of a likelihood map for the location of the source of a chemical plume dispersed under atmospheric turbulence under uniform wind conditions. The main contribution of this work is to extend previous proposals based on Bayesian inference with binary detections to the use of concentration information while at the same time being robust against the presence of background chemical noise. For that, the algorithm builds a background model with robust statistics measurements to assess the posterior probability that a given chemical concentration reading comes from the background or from a source emitting at a distance with a specific release rate. In addition, our algorithm allows multiple mobile gas sensors to be used. Ten realistic simulations and ten real data experiments are used for evaluation purposes. For the simulations, we have supposed that sensors are mounted on cars which do not have among its main tasks navigating toward the source. To collect the real dataset, a special arena with induced wind is built, and an autonomous vehicle equipped with several sensors, including a photo ionization detector (PID) for sensing chemical concentration, is used. Simulation results show that our algorithm, provides a better estimation of the source location even for a low background level that benefits the performance of binary version. The improvement is clear for the synthetic data while for real data the estimation is only slightly better, probably because our exploration arena is not able to provide uniform wind conditions. Finally, an estimation of the computational cost of the algorithmic proposal is presente

EFECTO DE CULTIVOS EN ASOCIO PEPINO (Cucumis sativus L.), PIPIAN (Cucúrbita pepo L.) Y FRIJOL DE VARA (Vigna unguiculata L. Walp), EN LA OCURRENCIA POBLACIONAL DE INSECTOS PLAGAS, BENEFICOS Y EL RENDIMIENTO EN TISMA, MASAYA

This study was carried out with the aim of comparing the effect of associated crops on the population occurrence of insect pests, beneficial insects and the equivalent land use. The study was established on the farm called "Berlin", located in the municipality of Tisma - Masaya, between the months of December 2006 to February 2007. For the establishment of the experiment, four plots were planted, one plot was planted on the basis of associated crops such as cucumber, squash and Chinese bean, and three plots were planted as single crops of cucumber, squash and Chinese bean. During the development of the experiment, weekly sampling was performed, and the following variables were taken: the number of insect pests and beneficial insects per plant per crop, and during the harvest, the yield of each crop was taken and the equivalent land use was calculated (UET). In general there was a trend of fewer insect pests and an increased number of beneficial insects in the associated crops compared with the single crops. The associated crops made the best use of land because it obtains yields of 31 cucumber, 40 squash and 11 Chinese bean % respectively over that of production of single crops, making the associated crops better use of land per unit area.Keywords: Associated crop, Insect pest, Beneficial insects, Equivalent land use.DOI: 10.5377/calera.v10i14.23El presente estudio se realizó con el objetivo de comparar el efecto que tiene el sistema en asocio de cultivos sobre la ocurrencia poblacional de insectos plagas, benéficos y el uso equivalente de la tierra. El estudio se estableció en la finca "Berlín", ubicada en el Municipio de Tisma - Masaya, en los meses de diciembre 2006 a febrero 2007. Para el desarrollo de esta investigación se establecieron cuatro parcelas, una parcela se sembró en arreglo de los cultivos (pepino, pipián y fríjol de vara) y tres parcelas se sembraron con los cultivos solos de pepino, pipián y fríjol de vara. En cada estación se tomaron semanalmente las siguientes variables: número de insectos plagas y benéficos por planta, y durante la cosecha, el rendimiento de cada cultivo para calcular el uso equivalente de la tierra (UET). En general se observó una tendencia de menor número de insectos plagas y mayor número de insectos benéficos en la parcela de los cultivos asociados en comparación con los cultivos solos, aunque no se encontró diferencias significativas entre los dos sistemas de cultivos. Se calculó el uso equivalente de la tierra (UET) y se encontró que el sistema en asocio (pepino, pipián y fríjol de vara) presentó el mejor aprovechamiento de la tierra al obtener rendimientos de 31, 40 y 11 % más de producción respectivamente que los cultivos solos, haciendo un mejor uso de la tierra por unidad de área. Palabras clave: Cultivos en asocio, Plaga, Insectos Benéficos, Uso equivalente de la tierra.DOI: 10.5377/calera.v10i14.2

Calculo de parámetros determinantes en la preparación de un circuito de ventilación en minería subterránea de carbón usando programación estructurada

La explotación de carbón toma cada vez más importancia, no sólo por la creciente demanda relacionada directamente a la industria energética y por encontrarse de forma abundante en la corteza terrestre, sino por los riesgos que ponen en peligro la vida y el bienestar de los trabajadores en la explotación subterránea del mineral. Tomando esto como punto de partida y siendo conscientes del alto número de accidentes que se han presentado en los últimos años, especialmente tragedias relacionadas al défi cit de la ventilación en las minas, se expone el presente artículo. El propósito del manuscrito es vincular y desarrollar técnicas de programación hacia la determinación de parámetros claves en el diseño de un sistema de ventilación en una explotación minera subterránea. Lo anterior conlleva a la disminución de problemas asociados a la ventilación en labores mineras y a la generación de consciencia sobre la importancia de la actividad, teniendo presente que la integridad física del personal en la mina debe ser garantizada y que la minería junto a la informática está a la vanguardia para la solución de problemas asociados a sus campos de aplicación

COMPARACIÓN de la OCURRENCIA poblacional de insectos plagas y BENÉFICOS en areglos de POLICULTIVO y MONOCULTIVO DE TOMATE (Lycopersicum esculentum, Mill), CHILTOMA (Capsicum annum, L.) y MAÍZ (Zea mays, L.)

Este estudio se realizó con el objetivo de comparar el efecto que tienen los asocios de cultivos sobre la ocurrencia de insectos plagas, artrópodos benéficos y el uso equivalente de la tierra. El estudio se estableció en la finca los Toruños, ubicada en el municipio de Tisma-Masaya, llevándose a cabo entre los meses de Junio a Septiembre del 2006. Para el desarrollo de esta investigación se seleccionó una finca representativa de un productor, en donde se establecieron cuatro parcelas, tres parcelas se sembraron con cultivos individuales o monocultivos (tomate, chiltoma, maíz) y una parcela se arregló en forma de policultivo (tomate, chiltoma, maíz). En cada estación se tomaron semanalmente las siguientes variables: número de insectos plagas por planta, número de artrópodos benéficos por planta y el rendimiento de cada cultivo para calcular el uso equivalente de la tierra. En general se observó una menor tendencia de insectos plagas en la parcela de policultivo en comparación con la parcela de monocultivo y a demás se encontró una mayor ocurrencia  poblacional de artrópodos benéficos en la parcela de policultivo en comparación con la parcela de monocultivos. Se calculó el uso equivalente de la tierra y se encontró que los mayores resultados de EUT lo presentaron los arreglos de tomate, chiltoma y maíz en policultivos, con valores de: 1.68, 1.5,1. 16, respectivamente dando como resultado un 68, 50 y 16 por ciento más de producción por unidad de área que los monocultivos. Se concluyó que los arreglos en asocio de cultivos tienen un efecto sobre la ocurrencia poblacional de insectos plagas y artrópodos benéficos y además se hace un mayor uso equivalente de la tierra. Palabras claves: Policultivos, Monocultivos, Insectos plagas, Insectos benéficos, uso equivalente de la tierra

A sequential acid-base (SAB) mechanism in the interstellar medium: The emergence of cis formic acid in dark molecular clouds

The abundance ratios between isomers of a COM observed in the ISM provides valuable information about the chemistry and physics of the gas and eventually, the history of molecular clouds. In this context, the origin of an abundance of c-HCOOH acid of only 6% the isomer c-HCOOH abundance in cold cores, remains unknown. Herein, we explain the presence of c-HCOOH in dark molecular clouds through the destruction and back formation of c-HCOOH and t-HCOOH in a cyclic process that involves HCOOH and highly abundant molecules such as HCO+ and NH3. We use high-level ab initio methods to compute the potential energy profiles for the cyclic destruction/formation routes of c-HCOOH and t-HCOOH. Global rate constants and branching ratios were calculated based on the transition state theory and the master equation formalism under the typical conditions of the ISM. The destruction of HCOOH by reaction with HCO+ in the gas phase leads to three isomers of the cation HC(OH)2+. The most abundant cation can react in a second step with other abundant molecules of the ISM like NH3 to form back c-HCOOH and t-HCOOH. This mechanism explains the formation of c-HCOOH in dark molecular clouds. Considering this mechanism, the fraction of c-HCOOH with respect t-HCOOH is 25.7%. To explain the 6% reported by the observations we propose that further destruction mechanisms of the cations of HCOOH should be taken into account. The sequential acid-base (SAB) mechanism proposed in this work involves fast processes with very abundant molecules in the ISM. Thus, HCOOH very likely suffers our proposed transformations in the conditions of dark molecular clouds. This is a new approach in the framework of the isomerism of organic molecules in the ISM which has the potential to try to explain the ratio between isomers of organic molecules detected in the ISM

Diploma Course on Digital Agriculture in Guatemala

CGIAR Research Initiatives on Digital Innovation and AgriLAC Resiliente have collaborated with different stakeholders to implement digital agriculture approaches for professionals in critical locations in the Central American Dry Corridor in 2022. The university diploma course aimed to strengthen the technical capacity of agricultural professionals in digital agriculture and allow them to make more informed, data-driven decisions in agrifood systems. The 90-hour diploma course is organized in to five modules (i) Human-centered design and digital inclusion, (ii) Data collection, data management, and data integration, (iii) Data science, (iv) Crop modeling, and (v) scaling digital innovations. Twenty-six agricultural professionals from various institutions, from government, non-government organizations (NGOs), growers' associations, and educational institutions to the private sector, completed the course on 16 December 2022

The structure of attitudes towards persons with disabilities: structural and network models

The study aims to examine the structure of third sector professionals’ attitudes towards people with disabilities. A novel approach is proposed from network psychometrics called exploratory graph analysis, in which the nodes represent the attitudes and the relational links represent the estimated statistical relationships. The Attitudes Scale toward Persons with Disabilities was applied, and 976 professionals participated, with an age range between 18 and 65 years. We compared the results of the three factor model obtained by confirmatory factor analysis with the structure of the attitude network. A high correspondence was observed between the items that make up the first factor of the model and the grouping of the nodes that represent them in the network. In addition, the nodes with the lowest centrality index corresponded with the least reliable indicators in the factorial model. In the network graph, the items were grouped into approximately three clusters; however, strong links were also observed between indicators belonging to different groups, which could help explain the empirical evidence in favourof a general attitude factor.El estudio pretende examinar la estructura de las actitudes hacia las personas con discapacidad de los profesionales del tercer sector, comparando para ello diferentes métodos exploratorios y confirmatorios. Se propone un enfoque novedoso desde el análisis de redes denominado análisis exploratorio de grafos en el que los nodos representan las actitudes y los vínculos relacionales representan las relaciones estadísticas estimadas. Se aplicó la Escala de actitudes hacia las personas con discapacidad, participaron 976 profesionales con un rango de edad entre 18 y 65 años. Se compararon los resultados del modelo de tres factores obtenido mediante análisis factorial confirmatorio con la estructura de la red de actitudes. Se observó una alta correspondencia entre los ítems que conforman el primer factor del modelo y la agrupación de los nodos que los representan en la red. Además, los nodos con menor centralidad correspondieron con los indicadores menos fiables en el modelo factorial. En el gráfico de redes los ítems parecen agruparse aproximadamente en tres clústeres; sin embargo también se observan nexos fuertes entre indicadores pertenecientes a distintos grupos, lo que podría ayudar a explicar la evidencia empírica a favor de un factor general de actitudes