765 research outputs found
Comentarios a la reflexión «Osteoporosis y ecografía ósea de calcáneo. Empresas farmacéuticas y atención primaria. ¿Qué estamos haciendo?»
Consistent performance measurement of a system to detect masses in mammograms based on blind feature extraction
BACKGROUND: Breast cancer continues to be a leading cause of cancer deaths among women, especially in Western countries. In the last two decades, many methods have been proposed to achieve a robust mammography‐based computer aided detection (CAD) system. A CAD system should provide high performance over time and in different clinical situations. I.e., the system should be adaptable to different clinical situations and should provide consistent performance. METHODS: We tested our system seeking a measure of the guarantee of its consistent performance. The method is based on blind feature extraction by independent component analysis (ICA) and classification by neural networks (NN) or SVM classifiers. The test mammograms were from the Digital Database for Screening Mammography (DDSM). This database was constructed collaboratively by four institutions over more than 10 years. We took advantage of this to train our system using the mammograms from each institution separately, and then testing it on the remaining mammograms. We performed another experiment to compare the results and thus obtain the measure sought. This experiment consists in to form the learning sets with all available prototypes regardless of the institution in which them were generated, obtaining in that way the overall results. RESULTS: The smallest variation from comparing the results of the testing set in each experiment (performed by training the system using the mammograms from one institution and testing with the remaining) with those of the overall result, considering the success rate for an intermediate decision maker threshold, was roughly 5%, and the largest variation was roughly 17%. But, if we considere the area under ROC curve, the smallest variation was close to 4%, and the largest variation was about a 6%. CONCLUSIONS: Considering the heterogeneity in the datasets used to train and test our system in each case, we think that the variation of performance obtained when the results are compared with the overall results is acceptable in both cases, for NN and SVM classifiers. The present method is therefore very general in that it is able to adapt to different clinical situations and provide consistent performance
Independent Component Analysis to Detect Clustered Microcalcification Breast Cancers
The presence of clustered microcalcifications is one of the earliest signs in breast cancer detection. Although there exist many studies broaching this problem, most of them are nonreproducible due to the use of proprietary image datasets. We use a known subset of the currently largest publicly available mammography database, the Digital Database for Screening Mammography (DDSM), to develop a computer-aided detection system that outperforms the
current reproducible studies on the same mammogram set. This proposal is mainly based on the use of extracted image features obtained by independent component analysis, but we also study the inclusion of the patient's age as a nonimage feature which requires no human expertise. Our system achieves an average of 2.55 false positives per image at a sensitivity of 81.8% and 4.45 at a sensitivity of 91.8% in diagnosing the BCRP_CALC_1 subset of DDSM
Beekeeping in Jalisco, México
The purpose of this study was to analyze the socioeconomic factors that influence the beekeeping process and describe the current situation in beekeeping technology development in the south and southeast regions of Jalisco. The study was conducted by reviewing secondary sources of documentary information and the primary information was obtained by means of a survey, analyzing demographic, social, technological, and economic variables. From January to April 2011, a stratified sampling was conducted of six strata of beekeepers, with a final sampling of 183 beekeepers. We applied a frequency analysis, ANOVA (Waller-Duncan), and contingency tables (χ2). The average age observed for the beekeepers was 47 years, with fewer women participating in the activity, and an above national average level of education. The majority keep their apiaries in rented premises, a high percentage outside the municipality where they live. The honey obtained is multiflora and the main harvest is in the autumn, with a honey yield per hive below the national average. A number of problems affect the production sector including environmental factors, production costs, and varroa. We observed little diversification; in addition to honey only beeswax is recovered, and only a minority keep a record of production costs. There is wide participation in beekeeping associations and in training provided by different public and private bodies. There is a willingness to adopt new technologies and equipment for honey production with good practice standards
Mapping participatory planning in Havana: patchwork legacies for a strengthened local governance
In 2019, Cuba approved a new political constitution that calls for deepening citizen participation to strengthen local governance. The emerging decentralization processes and the role of new actors in urban development open new possibilities for inclusive planning. While citizen participation is widely documented in the global South and under Western liberal democracy regimes, participatory urban planning in the context of Southern socialist cities such as Havana has been less scrutinized. This paper aims at mapping the framings, trajectories and legacies of such participatory planning initiatives. Based on mapping workshops and desktop research, we find that participatory initiatives within Havana are spatially dispersed, sporadic, lacking at the city level, and occurring in isolation at the neighbourhood level. We argue that establishing sustained participatory urban planning practices in Havana requires decision makers to scale outwards and upwards the lessons learned from existing initiatives to foster a city-wide participatory planning strategy
Selection and evaluation of third party logistics in the supply chain: A systematic review
[ES] A nivel mundial se estima que más del 85% de las principales empresas utilizan servicios logísticos externos, con tasas de crecimiento de este mercado de servicios proyectadas entre el 18 y 22% por año. Esta tendencia ha gene rado un creciente interés en los investigadores de la cadena de suministro por proponer diferentes enfoques para la selección y evaluación del desempeño de los proveedores de logística externa (3PL). En este artículo se propone una revisión sistemática analizando una muestra de artículos publicados en revistas indexadas con el objetivo de identificar las principales contribuciones sobre este tema. Este estudio muestra que la evaluación y selección de un 3PL es una decisión crítica y compleja, debido a la existencia de varios criterios de base imprecisa y subjetiva. Como resultado, se presentan características metodológicas, enfoques utilizados, modelos aplicados, atributos de las revistas e industrias que utilizan proveedores de logística externa. El costo, las tecnologías de la información implementadas por los proveedores de logística y la efectividad en los envíos y entregas a tiempo, son los criterios más valorados por las empresas para la evaluación y selección de 3PL. Los resultados de este estudio sirven a apoyo a los investigadores, como referencia que permite identificar algunas posibilidades para futuras investigaciones en el campo de los proveedores que ofertan servicios de logística externa, impulsando la competitividad en la cadena de suministro.[EN] Worldwide it is estimated that more than 85% of the main companies used external logistics services, with growth rates of this services market projected between 18 and 22 percent per year. This trend has generated a growing interest in supply chain researchers to propose different approaches for the selection and evaluation of the performance of third party logistics (3PL). This article proposes a systematic review analyzing a sample of articles published in indexed journals in order to identify the main contributions on this topic. This study shows the evaluation and selection of a 3PL is a critical and complex decision, due to the existence of several criteria of imprecise and subjective basis. As a result, methodological characteristics, approaches used, models applied, attributes of the magazines, and industries that use external logistics providers are presented. Cost, information technology implemented by logistics providers, and the effectiveness of shipments and deliveries on time, are the most valued criteria by companies for the evaluation and selection of 3PL. The results of this study provide support to researchers, as a reference that allows identifying some possibilities for future research in the field of providers that offer external logistics services, promoting competitiveness in the supply chain.Los autores expresan su reconocimiento al PRODEP UAEH (proyecto EXB-152), por el apoyo otorgado para la realización de este estudio
Potential Role of Insulin Growth-Factor-Binding Protein 2 as Therapeutic Target for Obesity-Related Insulin Resistance
Evidence from observational and in vitro studies suggests that insulin growth-factor-binding protein type 2 (IGFBP2) is a promising protein in non-communicable diseases, such as obesity, insulin resistance, metabolic syndrome, or type 2 diabetes. Accordingly, great efforts have been carried out to explore the role of IGFBP2 in obesity state and insulin-related diseases, which it is typically found decreased. However, the physiological pathways have not been explored yet, and the relevance of IGFBP2 as an important pathway integrator of metabolic disorders is still unknown. Here, we review and discuss the molecular structure of IGFBP2 as the first element of regulating the expression of IGFBP2. We highlight an update of the association between low serum IGFBP2 and an increased risk of obesity, type 2 diabetes, metabolic syndrome, and low insulin sensitivity. We hypothesize mechanisms of IGFBP2 on the development of obesity and insulin resistance in an insulin-independent manner, which meant that could be evaluated as a therapeutic target. Finally, we cover the most interesting lifestyle modifications that regulate IGFBP2, since lifestyle factors (diet and/or physical activity) are associated with important variations in serum IGFBP2
Tsunami generation potential of a strike slip fault tip in the westernmost Mediterranean
Tsunamis are triggered by sudden seafloor displacements, and usually originate from seismic activity at faults. Nevertheless, strike-slip faults are usually disregarded as major triggers, as they are thought to be capable of generating only moderate seafloor deformation; accordingly, the tsunamigenic potential of the vertical throw at the tips of strike-slip faults is not thought to be significant. We found the active dextral NW–SE Averroes Fault in the central Alboran Sea (westernmost Mediterranean) has a historical vertical throw of up to 5.4 m at its northwestern tip corresponding to an earthquake of Mw 7.0. We modelled the tsunamigenic potential of this seafloor deformation by Tsunami-HySEA software using the Coulomb 3.3 code. Waves propagating on two main branches reach highly populated sectors of the Iberian coast with maximum arrival heights of 6 m within 21 and 35 min, which is too quick for current early-warning systems to operate successfully. These findings suggest that the tsunamigenic potential of strike-slip faults is more important than previously thought, and should be taken into account for the re-evaluation of tsunami early-warning systems.Versión del edito
The influence of basin slope and fluvial flow on deltaic built-up processes off mountainous, seasonal rivers
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IFCP Riemann solver: Application to tsunami modelling using GPUs
In this work, we present a simplified two-layer model of Savage-Hutter type to simulate tsunamis
generated by landslides (see (Fern´andez et al. 2008)). A layer composed of fluidized granular material is
assumed to flow within an upper layer composed of an inviscid fluid (e.g. water). The sediment layer ismodelled
by a Savage-Hutter type model where buoyancy effects have been considered. The system is discretized using
IFCP finite volume scheme. The first order IFCP scheme was introduced in (Fern´andez et al. 2011) and it is
constructed by using a suitable decomposition of a Roe matrix by means of a parabolic viscosity matrix, that
captures information of the intermediate fields (Intermediate Field Capturing Parabola). Its extension to high
order and two-dimensional domains is straightforward. To conclude, some numerical examples are presente
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