3,658 research outputs found
The time dimension of the links between loss given default and the macroeconomy
Most studies focusing on the determinants of loss given default (LGD) have largely ignored possible lagged effects of the macroeconomy on LGD. We fill this gap by employing a wide set of macroeconomic covariates on a retail portfolio that represents 15% of the Czech consumer credit market over the period 2002-2012. We find an important time dimension to the links between LGD and the aggregate economy in the Czech Republic. The model that allows exclusively for contemporaneous effects includes a number of significant macroeconomic variables, some of which have non-intuitive signs. Nonetheless, a more general time structure of the LGD model makes current macroeconomic variables largely irrelevant and highlights the importance of delayed responses of LGD to the macroeconomic environment
The sustainable energy approach in the manufacture of cellular concrete
Cellular concrete holds one of the leading places in world practice of construction as a structural heat insulating material used in the construction and reconstruction of buildings and structures for various purposes. Excessive (reserve) porosity of cellular concrete provides its frost resistance (compensates expansion of water when freezing and the formed ice without destroying the material). Vapor permeability of cellular concrete provides fast removal of technological moisture from the material and the maintenance of normal moisture conditions in the rooms, and rather high air permeability contributes to the preservation of fresh air in the rooms. Thermal insulation and strength properties of cellular concrete allow erecting single-layer enclosing structures with the required thermal resistance from it. Cellular concretes are divided into aerated concrete and foam concrete, the operating, physical and mechanical parameters of which are almost the same with all other things being equal. According to the hydrothermal treatment method, cellular concrete is divided into two groups: autoclaved and non-autoclaved concrete (air hardening or steaming). The qualities of such concretes differ significantly, since autoclave treatment changes the mineralogical composition of concrete, which greatly affects the profitability of energy-related technological processes associated with the environment and ultimately forms the basis of environmental planning and management
Minimal Universal Extra Dimensions in CalcHEP/CompHEP
We present an implementation of the model of minimal universal extra
dimensions (MUED) in CalcHEP/CompHEP. We include all level-1 and level-2
Kaluza-Klein (KK) particles outside the Higgs sector. The mass spectrum is
automatically calculated at one loop in terms of the two input parameters in
MUED: the radius of the extra dimension and the cut-off scale of the model. We
implement both the KK number conserving and the KK number violating
interactions of the KK particles. We also account for the proper running of the
gauge coupling constants above the electroweak scale. The implementation has
been extensively cross-checked against known analytical results in the
literature and numerical results from other programs. Our files are publicly
available and can be used to perform various automated calculations within the
MUED model.Comment: 32 pages, 4 figures, 6 tables, invited contribution for New Journal
of Physics Focus Issue on 'Extra Space Dimensions', the model file can be
downloaded from http://home.fnal.gov/~kckong/mued
Probability Distribution Characteristics for Surface Air–Sea Turbulent Heat Fluxes over the Global Ocean
To analyze the probability density distributions of surface turbulent heat fluxes, the authors apply the twoparametric
modified Fisher–Tippett (MFT) distribution to the sensible and latent turbulent heat fluxes
recomputed from 6-hourly NCEP–NCAR reanalysis state variables for the period from 1948 to 2008. They
derived the mean climatology and seasonal cycle of the location and scale parameters of the MFT distribution.
Analysis of the parameters of probability distributions identified the areas where similar surface turbulent fluxes
are determined by the very different shape of probability density functions. Estimated extreme turbulent heat
fluxes amount to 1500–2000 W m22 (for the 99th percentile) and can exceed 2000 W m22 for higher percentiles
in the subpolar latitudes and western boundary current regions. Analysis of linear trends and interannual variability
in the mean and extreme fluxes shows that the strongest trends in extreme fluxes (more than 15 W m22
decade21) in the western boundary current regions are associated with the changes in the shape of distribution.
In many regions changes in extreme fluxes may be different from those for the mean fluxes at interannual and
decadal time scales. The correlation between interannual variability of themean and extreme fluxes is relatively
low in the tropics, the SouthernOcean, and the Kuroshio Extension region.Analysis of probability distributions
in turbulent fluxes has also been used in assessing the impact of sampling errors in theVoluntaryObserving Ship
(VOS)-based surface flux climatologies, allowed for the estimation of the impact of sampling in extreme fluxes.
Although sampling does not have a visible systematic effect onmean fluxes, sampling uncertainties result in the
underestimation of extreme flux values exceeding 100 W m22 in poorly sampled regions
No detection of methane on Mars from early ExoMars Trace Gas Orbiter observations
The detection of methane on Mars has been interpreted as indicating that geochemical or biotic activities could persist on Mars today. A number of different measurements of methane show evidence of transient, locally elevated methane concentrations and seasonal variations in background methane concentrations. These measurements, however, are difficult to reconcile with our current understanding of the chemistry and physics of the Martian atmosphere, which-given methane's lifetime of several centuries-predicts an even, well mixed distribution of methane. Here we report highly sensitive measurements of the atmosphere of Mars in an attempt to detect methane, using the ACS and NOMAD instruments onboard the ESA-Roscosmos ExoMars Trace Gas Orbiter from April to August 2018. We did not detect any methane over a range of latitudes in both hemispheres, obtaining an upper limit for methane of about 0.05 parts per billion by volume, which is 10 to 100 times lower than previously reported positive detections. We suggest that reconciliation between the present findings and the background methane concentrations found in the Gale crater would require an unknown process that can rapidly remove or sequester methane from the lower atmosphere before it spreads globally
Martian dust storm impact on atmospheric H<sub>2</sub>O and D/H observed by ExoMars Trace Gas Orbiter
Global dust storms on Mars are rare but can affect the Martian atmosphere for several months. They can cause changes in atmospheric dynamics and inflation of the atmosphere, primarily owing to solar heating of the dust. In turn, changes in atmospheric dynamics can affect the distribution of atmospheric water vapour, with potential implications for the atmospheric photochemistry and climate on Mars. Recent observations of the water vapour abundance in the Martian atmosphere during dust storm conditions revealed a high-altitude increase in atmospheric water vapour that was more pronounced at high northern latitudes, as well as a decrease in the water column at low latitudes. Here we present concurrent, high-resolution measurements of dust, water and semiheavy water (HDO) at the onset of a global dust storm, obtained by the NOMAD and ACS instruments onboard the ExoMars Trace Gas Orbiter. We report the vertical distribution of the HDO/H O ratio (D/H) from the planetary boundary layer up to an altitude of 80 kilometres. Our findings suggest that before the onset of the dust storm, HDO abundances were reduced to levels below detectability at altitudes above 40 kilometres. This decrease in HDO coincided with the presence of water-ice clouds. During the storm, an increase in the abundance of H2O and HDO was observed at altitudes between 40 and 80 kilometres. We propose that these increased abundances may be the result of warmer temperatures during the dust storm causing stronger atmospheric circulation and preventing ice cloud formation, which may confine water vapour to lower altitudes through gravitational fall and subsequent sublimation of ice crystals. The observed changes in H2O and HDO abundance occurred within a few days during the development of the dust storm, suggesting a fast impact of dust storms on the Martian atmosphere
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Comprehensive molecular characterization of gastric adenocarcinoma
Gastric cancer is a leading cause of cancer deaths, but analysis of its molecular and clinical characteristics has been complicated by histological and aetiological heterogeneity. Here we describe a comprehensive molecular evaluation of 295 primary gastric adenocarcinomas as part of The Cancer Genome Atlas (TCGA) project. We propose a molecular classification dividing gastric cancer into four subtypes: tumours positive for Epstein–Barr virus, which display recurrent PIK3CA mutations, extreme DNA hypermethylation, and amplification of JAK2, CD274 (also known as PD-L1) and PDCD1LG2 (also knownasPD-L2); microsatellite unstable tumours, which show elevated mutation rates, including mutations of genes encoding targetable oncogenic signalling proteins; genomically stable tumours, which are enriched for the diffuse histological variant and mutations of RHOA or fusions involving RHO-family GTPase-activating proteins; and tumours with chromosomal instability, which show marked aneuploidy and focal amplification of receptor tyrosine kinases. Identification of these subtypes provides a roadmap for patient stratification and trials of targeted therapies
Study of ordered hadron chains with the ATLAS detector
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A search for resonances decaying into a Higgs boson and a new particle X in the XH→qqbb final state with the ATLAS detector
A search for heavy resonances decaying into a Higgs boson () and a new particle () is reported, utilizing 36.1 fb of proton-proton collision data at 13 TeV collected during 2015 and 2016 with the ATLAS detector at the CERN Large Hadron Collider. The particle is assumed to decay to a pair of light quarks, and the fully hadronic final state is analysed. The search considers the regime of high resonance masses, where the and bosons are both highly Lorentz-boosted and are each reconstructed using a single jet with large radius parameter. A two-dimensional phase space of mass versus mass is scanned for evidence of a signal, over a range of resonance mass values between 1 TeV and 4 TeV, and for particles with masses from 50 GeV to 1000 GeV. All search results are consistent with the expectations for the background due to Standard Model processes, and 95% CL upper limits are set, as a function of and masses, on the production cross-section of the resonance
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