Análisis por confiabilidad de la estabilidad de muros de pilas excavadas considerando las incertidumbres de los parámetros

In geotechnical engineering, bored-pile wall stability is evaluated using deterministic design methods based on safety factors to establish a margin against failure. In recent years, reliability-based design methods have been adopted to include uncertainty in the assessment of bored-pile wall stability as well as in the calculation of the feasible embedment depth of the walls. In this study, an expanded reliability-based design approach, along with finite element analysis, was applied to conduct parametric analyses of bored-pile wall stability. In serviceability limit state design framework, the results indicate that cohesion and groundwater level are factors that significantly affect bored-pile wall stability. Moreover, high variability in the cohesion range causes great uncertainty to determine the embedment depth of bored-pile wall. The feasible embedment depth can reach 4 times the free height considering the maximum coefficient of variation (50 %) of the cohesion. In turn, when the groundwater level is located at the retained ground surface, the horizontal displacement of the upper end of the wall reaches 15.2 mm, i.e., 0.0038 times the free height of the wall, for which the soil mobilizes active earth pressures. It was also found that the resolution of probabilistic results is highly influenced by the number of iterations in Monte Carlo simulations.En ingeniería geotécnica, la estabilidad de muros de pilas excavadas es evaluada mediante métodos de diseño determinísticos que se basan en el uso de factores de seguridad para establecer un margen para la falla. En los últimos años, se han adoptado métodos de diseño basados en la confiabilidad para involucrar la incertidumbre en la evaluación de la estabilidad de los muros, así como para el cálculo de la profundidad de empotramiento factible para los muros. En este estudio, se aplica un enfoque de diseño basado en la confiabilidad ampliada para desarrollar análisis paramétricos de la estabilidad de un muro de pilas excavadas, junto con un análisis de elementos finitos. En el marco del diseño por estado límite de servicio, los resultados indican que la cohesión del suelo y el nivel freático son factores que afectan significativamente la estabilidad del muro. Una alta variabilidad en el rango de cohesión causa una gran variabilidad en la incertidumbre para determinar la profundidad de empotramiento del muro. La profundidad de empotramiento factible puede alcanzar 4 veces la altura libre considerando el coeficiente de variación máximo (50 %) de la cohesión del suelo. Por otro lado, cuando el nivel freático se ubica en la superficie del terreno retenido, el desplazamiento horizontal del extremo superior del muro alcanza 15.2 mm, equivalente a 0.0038 veces la altura libre del muro, para el cual el suelo alcanza a movilizar los empujes activos. También se encontró que la resolución de los resultados probabilísticos está altamente influenciada por el número de iteraciones en las simulaciones de Monte Carlo

Análisis y evaluación del riesgo de deslizamientos superficiales en un terreno montañoso tropical: implementación de modelos físicos simples

Shallow landslide risk denotes the losses or damages caused by the occurrence of this phenomenon and depends on the magnitude, related to its probability of occurrence, and its effect on the exposed elements, determined by its degree of vulnerability. In this research, a hazard, vulnerability and risk assessment of shallow landslides in a tropical mountainous terrain is carried out. The physical model SHALSTAB was used for the hazard assessment and other models of easy implementation to calculate the physical vulnerability of 8 dwellings and of the people within them. The risk of the structures is calculated, in economic terms, and the risk of loss of human lives, for people inside the dwellings, by means of an analysis of the consequences of these exposed elements given the occurrence of shallow landslides defined in the evaluation of the hazard. This methodology represents a tool that can be useful for land use planning and landslide risk management.El riesgo de deslizamientos superficiales expresa las pérdidas o daños causados por la ocurrencia de este fenómeno y depende de la magnitud, relacionada con su probabilidad de ocurrencia, y su efecto en los elementos expuestos, determinado por su grado de vulnerabilidad. En esta investigación se analizan y evalúan la amenaza, vulnerabilidad y riesgo de deslizamientos superficiales en un terreno montañoso tropical. Se utilizó el modelo físico SHALSTAB para el análisis de la amenaza y otros modelos de fácil implementación para calcular la vulnerabilidad física de ocho viviendas y de personas dentro de las mismas. Se calcula el riesgo de las estructuras, en términos económicos, y el riesgo de pérdidas de vidas humanas, para personas dentro de las viviendas, mediante un análisis de las consecuencias de estos elementos expuestos dada la ocurrencia de deslizamientos superficiales definidos en la evaluación de la amenaza. Esta metodología representa una herramienta que puede ser útil en planes de ordenamiento territorial y gestión del riesgo de movimientos en masa

Muscle Activation in Middle-Distance Athletes with Compression Stockings

The aim of this study was to evaluate changes in electromyographic activity with the use of gradual compression stockings (GCSs) on middle-distance endurance athletes’ performance, based on surface electromyography measurement techniques. Sixteen well-trained athletes were recruited (mean ± SD: age 33.4 ± 6.3 years, VO2max 63.7 ± 6.3 mL·kg−1·min−1, maximal aerobic speed 19.7 ± 1.5 km·h). The athletes were divided into two groups and were assigned in a randomized order to their respective groups according to their experience with the use of GCSs. Initially, a maximum oxygen consumption (VO2max) test was performed to standardize the athletes’ running speeds for subsequent tests. Afterward, electromyographic activity, metabolic, and performance variables for each group were measured with surface electromyography. In addition, blood lactate concentration was measured, both with and without GCSs, during 10 min at 3% above VT2 (second ventilatory threshold), all of which were performed on the track. Next, surface electromyography activity was measured during a 1 km run at maximum speed. No significant changes were found in electromyography activity, metabolic and performance variables with GCSs use (p > 0.164) in any of the variables measured. Overall, there were no performance benefits when using compression garments against a control condition

New insights into the use and circulation of reindeer antler in northern Iberia during the Magdalenian (ca. 21-13 cal ka BP)

Interactions between prehistoric foragers and reindeer at the end of the Pleistocene are still poorly documented in northern Iberia, particularly the reasons and means by which their antlers were collected, processed and circulated. Here we review the main osseous industries dated to between 21 and 13 cal ka BP, focusing on the use and circulation of reindeer antler as a raw material for the production of weapons and tools by Magdalenian foragers. Thirty-six reindeer antler artefacts were identified from 11 Iberian sites that are located at either end of the Pyrenees: the Cantabrian region to the west, and to a lesser extent, in Catalonia to the east. Despite biases in the identification of production objectives (end-products), a detailed techno-typological, chronological and geographical analysis of these assemblages reveals both the existence of a consistent reindeer antler industry in northern Iberia and long-distance connections between the Cantabrian region and the Pyrenees. The integration of contemporary macrofaunal data makes it possible to explore the extension of the reindeer?s ecological niche in northern Iberia, as well as strategies for the acquisition and circulation of reindeer antler in the peninsula. Assuming that some reindeer assemblages result from the import of raw materials to supply manufacturing activities, we propose a scenario where the acquisition of reindeer antlers may have been organised at a local scale in the Basque region, and potentially in the neighbouring territories of Navarre, Cantabria and Asturias. On the other hand, in Catalonia, the combination of both faunal and technological data supports the hypothesis that reindeer antlers were imported (along with pelts) over longer distances, probably from the northern Pyrenees.This research was primarily financed by an international collaboration between the Spanish Ministry of Science and Innovation (MCIN/AEI/10.13039/501100011033) and the European Union (NextGenerationEU/PRTR) as part of the HumAntler project (PCI2021-122053-2 B) based at the Grupo I + D + i EvoAdapta (UC). Funding was also provided by the UMR-5608 TRACES laboratory of the University of Toulouse and PID2020-114462 GB-I00 of the Spanish Ministry of Science and Innovation (University of Salamanca)

Definition of Rainfall Thresholds for Shallow Landslides in Colombian Tropical Mountainous Catchments as Debris Flow Triggering Mechanism

As a cascade precursor of the Debris Flow phenomenon, landslides generate economic losses and human fatalities worldwide, especially in mountainous and tropical countries like Colombia. This work proposes two different methodologies of defining rainfall thresholds as a tool for Early Warning Systems for Debris Flow occurrence in Colombian urban and mountainous catchments: Empirical-Statistical and Physically based. Empirical-Statistical rainfall thresholds are defined using several data sources such as rain gauges (pluviometers), radar, and satellite data allowing a different timing and spatial resolution in the definition. The definition of physically based rainfall thresholds the TRIGRS software is used in mountainous catchments with rainfall data from rain gauges, with the information from the safety factor map resulting in the simulations calculated as the cumulative density function from the histogram of the distributed safety factor allowing the understanding of how the instability varies in a catchment during different storms event

An Atlas of the circumnuclear regions of 75 Seyfert galaxies in the near-UV with HST Advanced Camera for Surveys

We present an atlas of the central regions of 75 Seyfert galaxies imaged in the near-UV with the Advanced Camera for Surveys of the Hubble Space Telescope at an average resolution of ~10pc. These data complement archival high resolution data from the Space Telescope at optical and near-IR wavelengths, creating an extremely valuable dataset for astronomers with a broad range of scientific interests. Our goal is to investigate the nature of the near-UV light in these objects, its relation to the circumnuclear starburst phenomenon, and the connection of this to the evolution and growth of the galaxy bulge and central black hole. In this paper, we describe the near-UV morphology of the objects and characterize the near-UV emission. We estimate the size and the luminosity of the emitting regions and extract the luminosity profile. We also determine the presence of unresolved compact nuclei. In addition, the circumnuclear stellar cluster population is identified, and the contribution of the stellar clusters to the total light, at this wavelength, is estimated. The size of the sample allows us to draw robust statistical conclusions. We find that {Seyfert 1} galaxies are completely dominated by its bright and compact nucleus, that remains point-like at this resolution, while we find almost no unresolved nucleus in Seyfert 2. The Seyfert types 1 and 2 are quite segregated in an asymmetry vs compactness plot. Stellar clusters are found somewhat more frequently in Sy2 (in ~70% of the galaxies) than in Sy1 (~57%), and contribute more to the total light in Sy2, but this two differences seem to be mostly due to the large contribution of the compact nucleus in Sy1, as the luminosity distribution of the clusters is similar in both Sy types.Comment: Accepted for publication in AJ, 58 pages, 20 figures. High-resolution figures for all the objects are available at http://www.iaa.es/~manuel/publications/paper01.htm

Genetic diversity of Phytophthora infestans in the Northern Andean region.

RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are.BACKGROUND: Phytophthora infestans (Mont.) de Bary, the causal agent of potato late blight, is responsible for tremendous crop losses worldwide. Countries in the northern part of the Andes dedicate a large proportion of the highlands to the production of potato, and more recently, solanaceous fruits such as cape gooseberry (Physalis peruviana) and tree tomato (Solanum betaceum), all of which are hosts of this oomycete. In the Andean region, P. infestans populations have been well characterized in Ecuador and Peru, but are poorly understood in Colombia and Venezuela. To understand the P. infestans population structure in the Northern part of the Andes, four nuclear regions (ITS, Ras, β-tubulin and Avr3a) and one mitochondrial (Cox1) region were analyzed in isolates of P. infestans sampled from different hosts in Colombia and Venezuela. RESULTS: Low genetic diversity was found within this sample of P. infestans isolates from crops within several regions of Colombia and Venezuela, revealing the presence of clonal populations of the pathogen in this region. We detected low frequency heterozygotes, and their distribution patterns might be a consequence of a high migration rate among populations with poor effective gene flow. Consistent genetic differentiation exists among isolates from different regions. CONCLUSIONS: The results here suggest that in the Northern Andean region P. infestans is a clonal population with some within-clone variation. P. infestans populations in Venezuela reflect historic isolation that is being reinforced by a recent self-sufficiency of potato seeds. In summary, the P. infestans population is mainly shaped by migration and probably by the appearance of variants of key effectors such as Avr3a

The experience of inflammatory bowel disease patients with healthcare: a survey with the IEXPAC instrument

[Abstract] To assess inflammatory bowel disease (IBD) patients' experience of chronic illness care and the relationship with demographic and healthcare-related characteristics.This cross-sectional survey used the Instrument to Evaluate the EXperience of PAtients with Chronic diseases (IEXPAC) questionnaire to identify parameters associated with a better healthcare experience for IBD patients. IEXPAC questionnaire responses are grouped into 3 factors - productive interactions, new relational model, and patient self-management, scoring from 0 (worst) to 10 (best experience). Scores were analyzed by bivariate comparisons and multiple linear regression models.Surveys were returned by 341 of 575 patients (59.3%, mean age 46.8 (12.9) years, 48.2% women). Mean (SD) IEXPAC score was 5.9 (2.0); scores were higher for the productive interactions (7.7) and patient self-management factors (6.7) and much lower for the new relational model factor (2.2). Follow-up by a nurse, being seen by the same physician, and being treated with a lower number of medicines were associated with higher (better) overall patient experience score, and higher productive interactions and self-management factor scores. A higher productive interactions score was also associated with patients receiving medication subcutaneously or intravenously. Higher new relational model scores were associated with follow-up by a nurse, affiliation to a patients' association, receiving help from others for healthcare, a lower number of medicines and a higher educational level.In patients with IBD, a better overall patient experience was associated with follow-up by a nurse, being seen by the same physician, and being treated with a lower number of medicines

HST/WFPC2 imaging of the circumnuclear structure of LLAGNs. I Data and nuclear morphology

To advance our knowledge of the nature of the central source in LLAGNs and its relation with stellar clusters, we are carrying out several imaging projects with HST at near-UV, optical and near-IR wavelengths. In this paper, we present the first results obtained with observations of the central regions of 57 LLAGNs imaged with the WFPC2 through any of the V (F555W, F547M, F614W) and I (F791W, F814W) filters that are available in the HST archive. The sample contains 34% of the LINERs and 36% of the TOs in the Palomar sample. The mean spatial resolution of these images is 10 pc. With these data we have built an atlas that includes structural maps for all the galaxies, useful to identify compact nuclear sources and, additionally, to characterize the circumnuclear environment of LLAGNs, determining the frequency of dust and its morphology. The main results obtained are: 1) We have not found any correlation between the presence of nuclear compact sources and emission-line type. Thus, nucleated LINERs are as frequent as nucleated TOs. 2) The nuclei of "Young-TOs" are brighter than the nuclei of "Old-TOs" and LINERs. These results confirm our previous results that Young-TOs are separated from other LLAGNs classes in terms of their central stellar population properties and brightness. 3) Circumnuclear dust is detected in 88% of the LLAGNs, being almost ubiquitous in TOs. 4) The dust morphology is complex and varied, from nuclear spiral lanes to chaotic filaments and nuclear disk-like structures. Chaotic filaments are as frequent as dust spirals; but nuclear disks are mainly seen in LINERs. These results suggest an evolutionary sequence of the dust in LLAGNs, LINERs being the more evolved systems and Young-TOs the youngest. The full collection of figures are at http://www.iaa.es/~rosa/research/LLAGNs2007/LLAGNs-HSTIma1.htmlComment: Paper accepted in AJ, pdf file and the full collection of figures are at the ULR: http://www.iaa.es/~rosa/research/LLAGNs2007/LLAGNs-HSTIma1.htm