3,079 research outputs found

    Systemic risk contributions: a credit portfolio approach

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    We put forward a Merton-type multi-factor portfolio model for assessing banks' contributions to systemic risk. This model accounts for the major drivers of banks' systemic relevance: size, default risk and correlation of banks' assets as a proxy for interconnectedness. We measure systemic risk in terms of the portfolio expected shortfall (ES). Banks' (marginal) risk contributions are calculated based on partial derivatives of the ES in order to ensure a full risk allocation among institutions. We compare the performance of an importance sampling algorithm with a fast analytical approximation of the ES and the marginal risk contributions. Furthermore, we show empirically for a portfolio of large international banks how our approach could be implemented to compute bank-specific capital surcharges for systemic risk or stabilisation fees. We find that size alone is not a reliable proxy for the systemic importance of a bank in this framework. In order to smooth cyclical fluctuations of the risk measure, we explore a time-varying confidence level of the ES. --systemic risk contributions,systemic capital charge,expected shortfall,importance sampling,granularity adjustment

    Relevance-Based Compression of Cataract Surgery Videos

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    In the last decade, the need for storing videos from cataract surgery has increased significantly. Hospitals continue to improve their imaging and recording devices (e.g., microscopes and cameras used in microscopic surgery, such as ophthalmology) to enhance their post-surgical processing efficiency. The video recordings enable a lot of user-cases after the actual surgery, for example, teaching, documentation, and forensics. However, videos recorded from operations are typically stored in the internal archive without any domain-specific compression, leading to a massive storage space consumption. In this work, we propose a relevance-based compression scheme for videos from cataract surgery, which is based on content specifics of particular cataract surgery phases. We evaluate our compression scheme with three state-of-the-art video codecs, namely H.264/AVC, H.265/HEVC, and AV1, and ask medical experts to evaluate the visual quality of encoded videos. Our results show significant savings, in particular up to 95.94% when using H.264/AVC, up to 98.71% when using H.265/HEVC, and up to 98.82% when using AV1.Comment: 11 pages, 5 figures, 3 table

    Deciphering the role of miR-71 in Echinococcus multilocularis early development in vitro.

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    Echinococcosis represents a major public health problem worldwide and is considered a neglected disease by the World Health Organization. The etiological agents are Echinococcus tapeworms, which display elaborate developmental traits that imply a complex control of gene expression. MicroRNAs (miRNAs), a class of small regulatory RNAs, are involved in the regulation of many biological processes such as development and metabolism. They act through the repression of messenger RNAs (mRNAs) usually by binding to the 3' untranslated region (3'UTR). Previously, we described the miRNome of several Echinococcus species and found that miRNAs are highly expressed in all life cycle stages, suggesting an important role in gene expression regulation. However, studying the role of miRNAs in helminth biology remains a challenge. To develop methodology for functional analysis of miRNAs in tapeworms, we performed miRNA knockdown experiments in primary cell cultures of Echinococcus multilocularis, which mimic the development of metacestode vesicles from parasite stem cells in vitro. First, we analysed the miRNA repertoire of E. multilocularis primary cells by small RNA-seq and found that miR-71, a bilaterian miRNA absent in vertebrate hosts, is one of the top five most expressed miRNAs. Using genomic information and bioinformatic algorithms for miRNA binding prediction, we found a high number of potential miR-71 targets in E. multilocularis. Inhibition of miRNAs can be achieved by transfection of antisense oligonucleotides (anti-miRs) that block miRNA function. To this end, we evaluated a variety of chemically modified anti-miRs for miR-71 knockdown. Electroporation of primary cells with 2'-O-methyl modified anti-miR-71 led to significantly reduced miR-71 levels. Transcriptomic analyses showed that several predicted miR-71 targets were up-regulated in anti-miR-treated primary cells, including genes potentially involved in parasite development, host parasite interaction, and several genes of as yet unknown function. Notably, miR-71-silenced primary cell cultures showed a strikingly different phenotype from control cells and did not develop into fully mature metacestodes. These findings indicate an important function of miR-71 in Echinococcus development and provide, for the first time, methodology to functionally study miRNAs in a tapeworm

    Aceptación de carne bovina obtenida a través de modificación genética y clonación por parte de estudiantes universitarios y adultos que trabajan en el sur de Chile

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    In order to compare the acceptance of beef obtained from a conventionally bred, cloned or genetically modified (GM) animal by working adults and university students, and to identify consumer segments in both subsamples, a survey of 400 people in southern Chile was applied, distributed by means of proportional allocation. Using a conjoint analysis in the total sample, it was determined that the production technology was more important than the price, origin, presentation or breed of the animal. The consumers preferred Argentinean beef, cut, from a conventional animal, at the lowest price. In both subsamples one segment was sensitive to the production technology, one to the price and one to the origin of the meat. Nevertheless, the proportion of adults who rejected cloning and GM was greater, whereas a significant proportion of students viewed meat from a cloned or GM animal positively. In both subsamples, the groups sensitive to the origin had a positive view of beef from a GM animal. The groups in the subsample of students were differentiated by the frequency of beef consumption. In both subsamples, the segments did not differ in the level of satisfaction with their food-related life.Con el objetivo de comparar la aceptación de carne bovina de un animal convencional, clonado y genéticamente modificado (GM) en adultos laboralmente activos y estudiantes universitarios, e identificar segmentos de consumidores en ambas submuestras, se aplicó una encuesta a 400 personas en el sur de Chile, distribuidas mediante afijación proporcional. Mediante análisis conjunto, en la muestra total se determinó que la tecnología de producción fue más importante que el precio, el origen, la presentación y la raza del animal. Los consumidores prefirieron carne argentina, al corte, de un animal convencional, al precio más bajo. En ambas sub-muestras se distinguió un segmento sensible a la tecnología de producción, uno sensible al precio y uno sensible al origen de la carne. Sin embargo, fue mayor la proporción de adultos que rechazó la clonación y la GM, mientras una importante proporción de estudiantes se mostró positivo frente a la carne de un animal GM y clonado. En ambas sub-muestras los grupos sensibles al origen se mostraron positivos frente a la carne de un animal GM. Los grupos de la sub-muestra de estudiantes se diferenciaron según la frecuencia de consumo de carne bovina. En ambas sub-muestras los segmentos no difirieron según el nivel de satisfacción con su alimentación.Fil: Schnettler, Berta. Universidad de La Frontera (Chile). Facultad de Ciencias Agropecuarias y Forestales. Departamento de Producción Agropecuaria.Fil: Velásquez, Carlos. Universidad de La Frontera (Chile). Facultad de Ciencias Agropecuarias y Forestales. Departamento de Producción Agropecuaria.Fil: Lobos, Germán. Universidad de Talca (Chile)Fil: Orellana, Ligia. Chile. Universidad de La Frontera. Centro de Psicología Económica y del Consumo.Fil: Sepúlveda, José. Chile. Universidad de La Frontera. Centro de Psicología Económica y del Consumo.Fil: Salinas-Oñate, Natalia. Chile. Universidad de La Frontera. Centro de Psicología Económica y del Consumo.Fil: Adasme-Berríos, Cristian. Universidad Católica del Maule (Talca, Chile)Fil: Grunert, Klaus G.

    a randomized controlled trial

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    Diurnal carbohydrate and fat distribution modulates glycaemic control in rodents. In humans, the optimal timing of both macronutrients and its effects on glycaemic control after prolonged consumption are not studied in detail. In this cross-over trial, 29 non-obese men were randomized to two four-week diets: (1) carbohydrate-rich meals until 13.30 and fat-rich meals between 16.30 and 22.00 (HC/HF) versus (2) inverse sequence of meals (HF/HC). After each trial period two meal tolerance tests were performed, at 09.00 and 15.40, respectively, according to the previous intervention. On the HF/HC diet, whole-day glucose level was increased by 7.9% (p = 0.026) in subjects with impaired fasting glucose and/or impaired glucose tolerance (IFG/IGT, n = 11), and GLP-1 by 10.2% (p = 0.041) in normal glucose-tolerant subjects (NGT, n = 18). Diet effects on fasting GLP-1 (p = 0.009) and PYY (p = 0.034) levels were observed in IFG/IGT, but not in NGT. Afternoon decline of glucose tolerance was more pronounced in IFG/IGT and associated with a stronger decrease of postprandial GLP-1 and PYY levels, but not with changes of cortisol rhythm. In conclusion, the HF/HC diet shows an unfavourable effect on glycaemic control in IFG/IGT, but not in NGT subjects. Consequently, large, carbohydrate-rich dinners should be avoided, primarily by subjects with impaired glucose metabolism

    Magnetic fields in single late-type giants in the Solar vicinity: How common is magnetic activity on the giant branches?

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    We present our first results on a new sample containing all single G, K and M giants down to V = 4 mag in the Solar vicinity, suitable for spectropolarimetric (Stokes V) observations with Narval at TBL, France. For detection and measurement of the magnetic field (MF), the Least Squares Deconvolution (LSD) method was applied (Donati et al. 1997) that in the present case enables detection of large-scale MFs even weaker than the solar one (the typical precision of our longitudinal MF measurements is 0.1-0.2 G). The evolutionary status of the stars is determined on the basis of the evolutionary models with rotation (Lagarde et al. 2012; Charbonnel et al., in prep.) and fundamental parameters given by Massarotti et al. (1998). The stars appear to be in the mass range 1-4 M ⊙, situated at different evolutionary stages after the Main Sequence (MS), up to the Asymptotic Giant Branch (AGB). The sample contains 45 stars. Up to now, 29 stars are observed (that is about 64% of the sample), each observed at least twice. For 2 stars in the Hertzsprung gap, one is definitely Zeeman detected. Only 5 G and K giants, situated mainly at the base of the Red Giant Branch (RGB) and in the He-burning phase are detected. Surprisingly, a lot of stars ascending towards the RGB tip and in early AGB phase are detected (8 of 13 observed stars). For all Zeeman detected stars v sin i is redetermined and appears in the interval 2-3 km/s, but few giants with MF possess larger v sin

    A spectroscopic study of component C and the extended emission around I Zw 18

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    Long-slit Keck II, 4m Kitt Peak, and 4.5m MMT spectrophotometric data are used to investigate the stellar population and the evolutionary status of I Zw 18C, the faint C component of the nearby blue compact dwarf galaxy I Zw 18. Hydrogen Hα\alpha and Hβ\beta emission lines are detected in the spectra of I Zw 18C, implying that ionizing massive stars are present. High signal-to-noise Keck II spectra of different regions in I Zw 18C reveal Hγ\gamma, Hδ\delta and higher order hydrogen lines in absorption. Several techniques are used to constrain the age of the stellar population in I Zw 18C. Ages derived from two different methods, one based on the equivalent widths of the Hα\alpha, Hβ\beta emission lines and the other on Hγ\gamma, Hδ\delta absorption lines are consistent with a 15 Myr instantaneous burst model. We find that a small extinction in the range AVA_V = 0.20 -- 0.65 mag is needed to fit the observed spectral energy distribution of I Zw 18C with that model. In the case of constant star formation, all observed properties are consistent with stars forming continuously between ~ 10 Myr and < 100 Myr ago. We use all available observational constraints for I Zw 18C, including those obtained from Hubble Space Telescope color-magnitude diagrams, to argue that the distance to I Zw 18 should be as high as ~ 15 Mpc. The deep spectra also reveal extended ionized gas emission around I Zw 18. Hα\alpha emission is detected as far as 30" from it. To a B surface brightness limit of ~ 27 mag arcsec−2^{-2} we find no observational evidence for extended stellar emission in the outermost regions, at distances > 15" from I Zw 18.Comment: 38 pages, 11 Postscript figures, accepted for publication in the Astrophysical Journa

    PSICOLOGIA ESCOLAR: A GESTÃO NO ENSINO FUNDAMENTAL EM TEMPOS DE PANDEMIA DO COVID-19

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