Influencia de la depresión en la ideación suicida de los estudiantes de la selva peruana

Objetivo: Determinar la influencia de la depresión en la ideación suicida de los estudiantes de la selva peruana. Materiales y métodos: Estudio transversal analítico, realizado en una población universitaria en la selva peruana. La variable dependiente fue la ideación suicida y la independiente fue la depresión, ambas fueron tomadas a través de las escalas modificadas para el Perú de Birleson y de Beck, respectivamente. Se cruzó estos sistemas y se les ajustó por otras variables. Resultados: Existe una fuerte asociación entre la ideación suicida y depresión (valor p<0,01). Además, los estudiantes universitarios con depresión presentaron con mayor frecuencia ideas suicidas en grado medio–alto (RP: 7,1; IC95 %: 3,8-13,2). Otras conductas que se asociaron a los grados de ideación suicida medio-alto fueron percibir que se tienen pocas posibilidades de ser felices en el futuro (RP: 0,4; IC95 %: 0,2-0,6), sentir que no son tomados en cuenta por su familia (RP: 6,5; IC95 %: 4,2-10,0) y sentir que la muerte podía generar alivio (RP: 6,8; IC95 %: 4,6-10,2). Conclusiones: Se encontró una asociación entre las variables ideación suicida y depresión, que está caracterizada por algunas percepciones y conductas que develan serios problemas de la esfera mental, lo que debe ser tomado en cuenta por las entidades educativas, para generar programas de detección y ayuda a los jóvenes estudiantes

Fast hierarchical coordinated controller for distributed battery energy storage systems to mitigate voltage and frequency deviations

This paper proposes a novel hierarchical optimal control framework to support frequency and voltage in multi-area transmission systems, integrating battery energy storage systems (BESSs). The design is based on the coordinated active and reactive power injection from the BESSs over conventional synchronous generator-based control for fast and timely mitigation of voltage and frequency deviations. The principle of this new idea is to use two hierarchical schemes, one physical and one logical. The objective of the first scheme prioritises the power injection from the BESSs installed in the area where a contingency occurs, consequently reducing the disturbance of the dynamics in the neighbouring areas. In the second scheme, operational rules for aggregated BESSs in each are incorporated, increasing the safety of the asset. The proposed approach exploits the advantages of time-synchronised measurements, the eigensystem realisation algorithm (ERA) identification technique, the optimal linear quadratic Gaussian (LQG) controllers and a new aggregating agent that coordinates the power injection of BESSs in a hierarchical and scalable scheme to precisely regulate frequency and voltage of modern transmission grids, increasing their reliability and stability. The feasibility and robustness of the proposal is demonstrated using simulated scenarios with significant load changes and three-phase, three-cycle faults on a modified Kundur-system with four interconnected areas, mitigating frequency and voltage contingencies in less than 450 ms

Real-time co-simulation of transmission and distribution networks integrated with distributed energy resources for frequency and voltage support

This paper proposes a real-time co-simulated framework to experimentally validate the dynamic performance of network-level controllers in power systems. The experiment setup includes the coordinated emulation of a transmission network linked to a distribution feeder and real distributed energy sources, working in a multi-platform and multi-manufacturer environment. The operation of an optimal hierarchical controller for voltage and frequency support of the transmission network, which exploits the power injection from battery energy storage systems (BESS), is investigated to demonstrate the feasibility, accuracy and effectiveness of the proposed setup based on a co-simulation environment. The results of different study cases implemented in the laboratory are presented, where a successful interconnection between real-time emulators and real hardware from different manufacturers was realised. The fast and timely response of the controller to disturbances caused by sudden load changes, three-phase faults and renewable generation losses is experimentally validated. Finally, the robustness of the developed test bench against noise and harmonic distortion of real signals is also demonstrated

Características metodológicas de las evaluaciones de tecnologías sanitarias elaboradas en Perú, 2019-2021

Background: Limitations have been reported to comply with good methodological practices in the development of health technology assessments (HTA). Therefore, the objective of the present study was to describe the methodological characteristics of the HTAs carried out in Peru, between 2019-2021. Methods: Descriptive study. We are looking for Peruvian institutions that prepare HTAs whose reports are accessible to the public. We collected the total number of HTAs produced by these institutions per year, and we collected the characteristics of the HTAs produced during the 2019-2021 period. Results: Three Peruvian institutions developed at least three public HTAs between 2019-2021: The Institute for the Evaluation of Technologies in Health and Research (IETSI) (n=142), the Unit for the Analysis and Generation of Evidence in Public Health (UNAGESP) (n=60), and the National Institute of Neoplastic Diseases (INEN) (n=40). The HTAs of UNAGESP did not reach a decision, while 35.9% of those of IETSI and 70.0% of those of INEN concluded in favor of the evaluated technology. All STDs explained the methodology used and performed systematic searches. However, few presented the risk of bias assessment of the included studies (17.4%), the certainty of the evidence (4.6%), or the benefits and harms per outcome (14.4%). None of the HTAs carried out cost studies or made explicit the methodology used to reach the decision. Conclusions: The HTAs evaluated presented favorable methodological aspects and certain shortcomings (in topics such as the report in the evaluation of risk of bias and certainty of the evidence, presentation of benefits and harms by outcome, and explanation of the methodology used to make decisions).Introducción: Se han reportado limitaciones para cumplir con buenas prácticas metodológicas en el desarrollo de evaluaciones de tecnologías sanitarias (ETS). Por ello, el objetivo del presente estudio fue describir las características metodológicas de las ETS elaboradas en Perú, entre 2019-2021. Métodos: Estudio descriptivo. Buscamos las instituciones peruanas que elaboren ETS cuyos informes sean accesibles al público. Recolectamos el número total de ETS que elaboraron estas instituciones por año, y recolectamos las características de las ETS elaboradas durante el periodo 2019-2021. Resultados: Tres instituciones peruanas elaboraron al menos tres ETS públicas entre 2019-2021: El Instituto de Evaluación de Tecnologías en Salud e Investigación (IETSI) (n=142), la Unidad de Análisis y Generación de Evidencias en Salud Pública (UNAGESP) (n=60), y el Instituto Nacional de Enfermedades Neoplásicas (INEN) (n=40). Las ETS de UNAGESP no brindaron una decisión, mientras que 35,9% de las de IETSI y 70,0% de las de INEN concluyeron a favor de la tecnología evaluada. Todas las ETS explicaron la metodología usada y realizaron búsquedas sistemáticas. Sin embargo, pocas presentaron la evaluación de riesgo de sesgo de los estudios incluidos (17,4%), la certeza de la evidencia (4,6%), o los beneficios y daños por desenlace (14,4%). Ninguna ETS realizó estudios de costos ni explicitó la metodología usada para llegar a la decisión. Conclusiones: Las ETS evaluadas presentaron aspectos metodológicos favorables y ciertas falencias (en temas como el reporte en la evaluación de riesgo de sesgo y certeza de la evidencia, presentación de beneficios y daños por desenlace, y explicitación de la metodología usada para tomar decisiones)

Genome-wide association studies for methane production in dairy cattle

© 2019 by the authors. Licensee MDPI, Basel, Switzerland. Genomic selection has been proposed for the mitigation of methane (CH4) emissions by cattle because there is considerable variability in CH4 emissions between individuals fed on the same diet. The genome-wide association study (GWAS) represents an important tool for the detection of candidate genes, haplotypes or single nucleotide polymorphisms (SNP) markers related to characteristics of economic interest. The present study included information for 280 cows in three dairy production systems in Mexico: 1) Dual Purpose (n = 100), 2) Specialized Tropical Dairy (n = 76), 3) Familiar Production System (n = 104). Concentrations of CH4 in a breath of individual cows at the time of milking (MEIm) were estimated through a system of infrared sensors. After quality control analyses, 21,958 SNPs were included. Associations of markers were made using a linear regression model, corrected with principal component analyses. In total, 46 SNPs were identified as significant for CH4 production. Several SNPs associated with CH4 production were found at regions previously described for quantitative trait loci of composition characteristics of meat, milk fatty acids and characteristics related to feed intake. It was concluded that the SNPs identified could be used in genomic selection programs in developing countries and combined with other datasets for global selection

Direct measurements of the effects of salt and surfactant on interaction forces between colloidal particles at water-oil interfaces

The forces between colloidal particles at a decane-water interface, in the presence of low concentrations of a monovalent salt (NaCl) and of the surfactant sodium dodecylsulfate (SDS) in the aqueous subphase, have been studied using laser tweezers. In the absence of electrolyte and surfactant, particle interactions exhibit a long-range repulsion, yet the variation of the interaction for different particle pairs is found to be considerable. Averaging over several particle pairs was hence found to be necessary to obtain reliable assessment of the effects of salt and surfactant. It has previously been suggested that the repulsion is consistent with electrostatic interactions between a small number of dissociated charges in the oil phase, leading to a decay with distance to the power -4 and an absence of any effect of electrolyte concentration. However, the present work demonstrates that increasing the electrolyte concentration does yield, on average, a reduction of the magnitude of the interaction force with electrolyte concentration. This implies that charges on the water side also contribute significantly to the electrostatic interactions. An increase in the concentration of SDS leads to a similar decrease of the interaction force. Moreover the repulsion at fixed SDS concentrations decreases over longer times. Finally, measurements of three-body interactions provide insight into the anisotropic nature of the interactions. The unique time-dependent and anisotropic interactions between particles at the oil-water interface allow tailoring of the aggregation kinetics and structure of the suspension structure.Comment: Submitted to Langmui

FY17 Report Summaries of Five Completed Center Innovation Fund (CIF) Projects for the Highlights/Abstract Section of the FY 2018 CIF Annual Report

The Center Innovation Fund Annual Report for FY18 is an annual report for Space Technology Mission Directorate (STMD) Leadership, STMD Principle Technologists, and Center Innovation Fund Management. Attached is the Highlights/Abstract section of this annual report, which is the only section to be shared outside of NASA. Contributors were asked not to include any SBU information for these report summaries

Spectral-based mesh segmentation

In design and manufacturing, mesh segmentation is required for FACE construction in boundary representation (BRep), which in turn is central for featurebased design, machining, parametric CAD and reverse engineering, among others -- Although mesh segmentation is dictated by geometry and topology, this article focuses on the topological aspect (graph spectrum), as we consider that this tool has not been fully exploited -- We preprocess the mesh to obtain a edgelength homogeneous triangle set and its Graph Laplacian is calculated -- We then produce a monotonically increasing permutation of the Fiedler vector (2nd eigenvector of Graph Laplacian) for encoding the connectivity among part feature submeshes -- Within the mutated vector, discontinuities larger than a threshold (interactively set by a human) determine the partition of the original mesh -- We present tests of our method on large complex meshes, which show results which mostly adjust to BRep FACE partition -- The achieved segmentations properly locate most manufacturing features, although it requires human interaction to avoid over segmentation -- Future work includes an iterative application of this algorithm to progressively sever features of the mesh left from previous submesh removal