3,083 research outputs found

    Impact of grading on steady-state strength

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    International audienceIn the mining industry, waste dumps are earthen structures typically built by loose waste tipping. They may reach heights of hundreds of metres and undergo large deformations. For this reason, their stability design is based on the steady-state shear strength of the waste material. Waste materials are widely graded and may contain particles of up to metric order. Particle shape depends on the pattern of dissecting discontinuities at the source rock mass and the relation between the size of the fragments and discontinuity spacing. The shear strength of this material is determined in the laboratory using scaled samples with altered particle-size distribution (PSD). However, altering the PSD is known to impact shear strength, and this impact is poorly studied. The representativeness of laboratory parameters obtained from scaled samples is thus arguable. Discrete-element simulations are used here to investigate steady-state shear strength changes with the alteration of the PSD when particle size and shape are correlated. It is observed that shear strength changes result from the variation of the particle shapes induced by the alteration of the PSD. Consequently, identifying size−shape correlations and their potential impact on shear strength is of paramount importance when scaling materials for laboratory testing

    Actividad ovárica y tasa de gestación en novillas suplementadas en el Trópico Húmedo de Costa Rica

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    Se determinó el efecto de la suplementación sobre la actividad ovárica y tasa de gestación en novillas Bosindicus (n=41) nulíparas de dos a tres años, divididas aleatoriamente en dos grupos: el suplementado (GS n=21) con un concentrado comercial (13,5% PC, 2,850 Mcal ED/kg MS) a razón del 1% del peso; con un periodo de 15 días de adaptación más 30 de suplementación y el testigo (GNS n=20). Ambos pastando Estrella Africana (Cynodonplestostachium), Ratana (Ischaemumindicum) y Tanzania (Panicummaximum); agua y sales minerales ad libitum). Las hembras se sincronizaron con Crestar® y servidas con dos toros de fertilidad probada. El diseño experimental fue al azar utilizando el programa estadístico JMP 10® de SAS Institute Inc. para el análisis. La condición corporal (CC) y grasa dorsal (GD) no son diferentes (P>0.05) así como los porcentajes entre grupos para actividad ovárica (ciclicidad y estructuras ováricas), tasa de preñez, los eventos de ciclicidad y gestación a lo largo del tiempo (P>0.05). La estimación de ocurrencia de la gestación en función del suplemento y la ciclicidad, según el modelo: Gest = f(GEST, CYC, TRAT) no mostró efecto del tratamiento (P>0.05) pero si significancia en los momentos de detección de la gestación (día 33 y día 45 respectivamente) entre grupos (P< 0.0001). En conclusión, el método de suplementación ensayado no tuvo mayor efecto sobre las variables estudiadas

    Análisis y selección de los parámetros de configuración para un localizador de fallas monofásicas aplicado a sistemas de distribución

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    Debido a las regulaciones asociadas con calidad de potencia, el problema de la localización de fallas en sistemas eléctricos ha tomado una gran importancia, principalmente para las empresas dedicadas a la distribución de energía eléctrica. En este artículo se presenta un algoritmo de clasificación estadística basado en una función de probabilidad difusa, que se utiliza para localizar fallas monofásicas en los sistemas de distribución, debido a su alta tasa se ocurrencia. El algoritmo propuesto se prueba en un sistema de distribución real, en el cual se obtienen errores promedio de 3,53% en la identificación de la zona en falla. A partir de los resultados se demuestra la aplicabilidad de este tipo de metodologías en sistemas reales

    Complex regional pain syndrome (CRPS), a review

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    Complex regional pain syndrome is a chronic and painful condition that affects the quality of life of patients. It is usually triggered by a traumatic event of the soft tissues involving the nervous tissue. Although the factors that cause the syndrome are varied and not well known, different etiopathologic concepts have been proposed to explain the presence of this syndrome, such as autonomic dysfunction and changes in CNS plasticity, among others. The patient characteristically presents pain, sensory abnormalities, vasomotor disturbances in the skin, edema, changes in sweating, and motor alterations. The pain is associated with changes in the autonomic nervous system and has a distal predominance. Since there is no definitive diagnostic test, diagnosis is mainly based on a complete medical history and physical examination. Treatment is multidisciplinary and based on pain relief. Although in most cases evolution is favorable, rapid diagnosis and treatment are recommended to avoid dystrophic stage as much as possibl

    Ximena, variedad de nochebuena (Euphorbia pulcherrima Willd. ex Klotzsch) para decorar espacios de interior

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    Objective: To describe the variety of Ximena poinsettia based on UPOV guidelines and to evaluate its behavior with a cooperating producer in Morelos state.Design/methodology/approach: The variety was generated by the genotechnical methods of hybridization, recurrent selection and use of the grafting method. The varietal description was made based on the document of the Union for the Protection of New Varieties of Plants (UPOV). The experimental design used was a completely randomized, with 10 repetitions. Vegetative and bract characters of the plant were recorded. The information was studied by analysis of variance and Tukey means comparison test (P? 0.05).Results: Ximena is tall, large, with intermediate branching. The leaf is oval, long and wide with a medium length petiole. Elliptical bracts, red color, without torsion and roughness between the nerves. The width of the top is medium, yellow ciatio glands, and without any deformation. Ximena's response was statistically similar to the two controls in stem diameter, number of internodes, leaf width, leaf petiole length and bract. Instead, it was statistically superior in bract length, bract canopy width, and diameter of ciatio.Limitations on study/implications: The variety is maintained as an original plant, from which commercial crops will be established. Therefore, it requires adequate nutrition and conditions that do not allow its floral differentiation.Findings/conclusions: Ximena's behavior and archetype was comparable to that of commercial varieties, it has aesthetic characteristics that the market demands, it can be competitive and it is considered a candidate to diversify the offer of poinsettias plants in the Christmas season.Objetivo: Describir la variedad de nochebuena Ximena en base a directrices de la UPOV y evaluar su comportamiento con un productor cooperante en el estado de Morelos.Diseño/metodología/aproximación: La variedad se generó mediante los métodos genotécnicos de hibridación, selección recurrente y uso de la técnica de injerto. La descripción varietal se realizó en base al documento de la Unión para la Protección de las Obtenciones Vegetales (UPOV). El diseño experimental utilizado fue un completamente al azar con 10 repeticiones. Se registraron caracteres vegetativos y de bráctea de la planta. La información se estudió mediante análisis de varianza y prueba de comparación de medias Tukey (P? 0.05).Resultados: Ximena presenta porte alto, de amplitud grande con ramificación intermedia. La hoja de forma oval, larga y ancha con peciolo de longitud media. Brácteas de forma elíptica, color rojo, sin torsión y rugosidad entre los nervios. La anchura de la cima es media, glándulas del ciatio de color amarillo de tamaño medio sin alguna deformación. La respuesta de Ximena fue estadísticamente similar a los dos testigos en diámetro del tallo, número de entrenudos, ancho de hoja, longitud de peciolo de hoja y bráctea. En cambio, fue superior estadísticamente en longitud de bráctea, amplitud de dosel de bráctea y diámetro de ciatio.Limitaciones del estudio/implicaciones: La variedad se mantiene como planta madre, a partir de la cual se van a establecer cultivos comerciales. Por lo que, requiere adecuada nutrición y condiciones que no permitan su diferenciación floral.Hallazgos/conclusiones: El comportamiento y arquetipo de Ximena fue comparable a la de variedades comerciales, posee características estéticas que demanda el mercado, puede ser competitiva y se considera candidata para diversificar la oferta de plantas de nochebuena en la temporada de navidad

    Evaluation of the INCREMENT-CPE, Pitt Bacteremia and qPitt Scores in Patients with Carbapenem-Resistant Enterobacteriaceae Infections Treated with Ceftazidime–Avibactam

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    Background The aim of this study was to evaluate the predictive performance of the INCREMENT-CPE (ICS), Pitt bacteremia score (PBS) and qPitt for mortality among patients treated with ceftazidime–avibactam for carbapenem-resistant Enterobacteriaceae (CRE) infections. Methods Retrospective, multicenter, cohort study of patients with CRE infections treated with ceftazidime–avibactam between 2015 and 2019. The primary outcome was 30-day all-cause mortality. Predictive performance was determined by assessing discrimination, calibration and precision. Results In total, 109 patients were included. Thirty-day mortality occurred in 18 (16.5%) patients. There were no significant differences in discrimination of the three scores [area under the curve (AUC) ICS 0.7039, 95% CI 0.5848–0.8230, PBS 0.6893, 95% CI 0.5709–0.8076, and qPitt 0.6847, 95% CI 0.5671–0.8023; P > 0.05 all pairwise comparisons]. All scores showed adequate calibration and precision. When dichotomized at the optimal cut-points of 11, 3, and 2 for the ICS, PBS, and qPitt, respectively, all scores had NPV > 90% at the expense of low PPV. Patients in the high-risk groups had a relative risk for mortality of 3.184 (95% CI 1.35–8.930), 3.068 (95% CI 1.094–8.606), and 2.850 (95% CI 1.016–7.994) for the dichotomized ICS, PBS, and qPitt, scores respectively. Treatment-related variables (early active antibiotic therapy, combination antibiotics and renal ceftazidime–avibactam dose adjustment) were not associated with mortality after controlling for the risk scores. Conclusions In patients treated with ceftazidime–avibactam for CRE infections, mortality risk scores demonstrated variable performance. Modifications to scoring systems to more accurately predict outcomes in the era of novel antibiotics are warranted

    Paula Poinsettia (Euphorbia pulcherrima Willd. ex Klotzsch) indoor variety

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    Objective: Evaluate the behavior of the poinsettia variety (Euphorbia pulcherrima Willd. ex Klotzsch) called Paula and describe its characteristics based on the guidelines of the International Union for the Protection of New Varieties of Plants. Design/methodology/approach: The genetic improvement process was by hybridization and selection. To promote compaction and greater branching, it was grafted on a commercial variety. The cuttings of this gave rise to the variety Paula, which was described in 2020 with the Guidelines for the Execution of Examination of Distinctness, Uniformity and Stability of Euphorbia pulcherrima Willd. ex Klotzsch of the International Union for the Protection of New Varieties of Plants. A completely randomized experimental design with 10 replications was used. Vegetative and bract characters were recorded and analysis of variance was applied, as well as a mean comparison test using Tukey (P≤ 0.05). Results: Paula presented medium size, wide breadth and medium branching. Stem with weak intensity of green color in the middle third. Oval-shaped leaves, long in length and broad in width, a single color of medium intensity, wedge-shaped at the base, long-length petiole with weak intensity of the green color of the beam. With many elliptical red bracts of medium length and narrow width. Compared to other INIFAP varieties, Paula presented statistical differences in vegetative and bract characters. Limitations on study/implications: Commercial production of poinsettia is done by taking advantage of asexual propagation. The original plant must be kept in a vegetative state, through comprehensive and intensive management in order to avoid flowering and thus obtain a continuum of propagation material. Findings/conclusions: Paula is of intermediate cycle, with qualitative and competitive characteristics in size, branching and red color of the bract. It can satisfy the taste and preference of consumers in the national and even international markets.Objective: To evaluate the behavior of the Paula poinsettia variety (Euphorbia pulcherrima Willd. ex Klotzsch) and to describe its characteristics, based on the guidelines established by the International Union for the Protection of New Varieties of Plants (UPOV). Design/Methodology/Approach: The genetic improvement included hybridization and selection techniques. To promote compaction and greater branching, it was grafted on a commercial variety. The cuttings obtained gave rise to the Paula variety (Euphorbia pulcherrima Willd. ex Klotzsch), which was described in 2020, based on the Guidelines for the Conduct of Tests for Distinctness, Uniformity and Stability of the International Union for the Protection of New Varieties of Plants. A completely randomized experimental design with 10 replications was used. Vegetative and bract characteristics were recorded and an analysis of variance was applied, as well as a Tukey’s mean comparison test (P≤ 0.05). Results: The Paula variety is medium-sized and has a wide breadth and medium branching. It is pale green in the middle third of the stem. It has oval-shaped, long, and broad leaves of the same medium-intensity color, and a wedge-shaped base. It has a long petiole with a pale green upper side. This variety also has many elliptical red bracts of medium length and narrow width. Compared to other INIFAP varieties, the vegetative and bract characteristics of Paula presented statistical differences. Study Limitations/Implications: The commercial production of poinsettia is carried out through asexual propagation. The mother plant is kept in a vegetative state, through comprehensive and intensive management, preventing its flowering and obtaining a continuum of propagation material. Findings/Conclusions: Paula has an intermediate cycle, with quality and competitive size, branching, and color of the bract (red). It can satisfy the taste and preference of consumers in the domestic and even foreign market

    Parent-of-origin-specific allelic associations among 106 genomic loci for age at menarche.

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    Age at menarche is a marker of timing of puberty in females. It varies widely between individuals, is a heritable trait and is associated with risks for obesity, type 2 diabetes, cardiovascular disease, breast cancer and all-cause mortality. Studies of rare human disorders of puberty and animal models point to a complex hypothalamic-pituitary-hormonal regulation, but the mechanisms that determine pubertal timing and underlie its links to disease risk remain unclear. Here, using genome-wide and custom-genotyping arrays in up to 182,416 women of European descent from 57 studies, we found robust evidence (P < 5 × 10(-8)) for 123 signals at 106 genomic loci associated with age at menarche. Many loci were associated with other pubertal traits in both sexes, and there was substantial overlap with genes implicated in body mass index and various diseases, including rare disorders of puberty. Menarche signals were enriched in imprinted regions, with three loci (DLK1-WDR25, MKRN3-MAGEL2 and KCNK9) demonstrating parent-of-origin-specific associations concordant with known parental expression patterns. Pathway analyses implicated nuclear hormone receptors, particularly retinoic acid and γ-aminobutyric acid-B2 receptor signalling, among novel mechanisms that regulate pubertal timing in humans. Our findings suggest a genetic architecture involving at least hundreds of common variants in the coordinated timing of the pubertal transition
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