3,079 research outputs found
Systemic risk contributions: a credit portfolio approach
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
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.
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
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
tecnologÃa 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 tecnologÃa 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 PsicologÃa Económica y del Consumo.Fil: Sepúlveda, José.
Chile. Universidad de La Frontera. Centro de PsicologÃa Económica y del Consumo.Fil: Salinas-Oñate, Natalia.
Chile. Universidad de La Frontera. Centro de PsicologÃa Económica y del Consumo.Fil: Adasme-BerrÃos, Cristian.
Universidad Católica del Maule (Talca, Chile)Fil: Grunert, Klaus G.
a randomized controlled trial
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?
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
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 H and H 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 H, H
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 H,
H emission lines and the other on H, H absorption lines
are consistent with a 15 Myr instantaneous burst model. We find that a small
extinction in the range = 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. H emission is detected as far as 30" from
it. To a B surface brightness limit of ~ 27 mag arcsec 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
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Diurnal distribution of carbohydrates and fat affects substrate oxidation and adipokine secretion in humans.
BACKGROUND: A diet in which fat is mainly eaten in the morning and carbohydrates mainly in the evening (compared with the reverse order) was recently shown to worsen glycemic control in people with prediabetes. OBJECTIVE: We investigated the effects of these dietary patterns on energy metabolism, and on the daily profiles of circulating lipids, adipokines, and inflammatory markers. DESIGN: In a randomized controlled crossover trial, 29 nonobese men (with normal glucose tolerance, n = 18; or impaired fasting glucose/glucose tolerance, n = 11) underwent 2 isocaloric 4-wk diets: 1) carbohydrate-rich meals until 1330 and fat-rich meals between 1630 and 2200 (HC/HF); or 2) the inverse sequence of meals (HF/HC). During a 12-h clinical investigation day after each intervention period, 2 meal tolerance tests were performed, at 0900 and 1540, respectively. Substrate oxidation and concentrations of circulating lipids, adipokines, and cytokines were assessed pre- and postprandially. The postprandial inflammatory response in leukocytes was analyzed ex vivo. RESULTS: Fasting carbohydrate oxidation decreased (P = 0.004) and lipid oxidation increased (P = 0.012) after the HC/HF diet. Fasting concentrations of blood markers did not differ between diets. The diets modulated the daily profiles of carbohydrate oxidation, lipid oxidation, and β-hydroxybutyrate, although the average daily values of these parameters showed no difference between the diets, and no interaction between diet and glucose tolerance status. Diurnal patterns of triglycerides, low-density lipoprotein cholesterol, leptin, visfatin, and of LPS-induced cytokine secretion in blood leukocytes were also modulated by the diets. Average daily concentrations of leptin (P = 0.017) and visfatin (P = 0.041) were lower on the HF/HC diet than on the HC/HF diet. CONCLUSIONS: Diurnal distribution of carbohydrates and fat affects the daily profiles of substrate oxidation, circulating lipids, and cytokine secretion, and alters the average daily concentrations of adipokine secretion in nonobese nondiabetic humans. The study was registered at clinicaltrials.gov as NCT02487576
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