14 research outputs found
The subtraction method for top quark production at hadron colliders
We consider QCD radiative corrections to top-quark pair production at hadron
colliders. We use the subtraction formalism to perform a
fully-differential computation for this process. Our calculation is accurate up
to the next-to-leading order in QCD perturbation theory and it includes all the
flavour off-diagonal partonic channels at the next-to-next-to-leading order. We
present a comparison of our numerical results with those obtained with the
publicly available numerical programs MCFM and Top++.Comment: Few references and comments added, expanded discussion on the qt
subtraction method, result unchanged, version published in EPJ
Transverse-momentum resummation fo top-quark pair production at the LHC
We consider transverse-momentum resummation for top-quark pair production in
hadron collisions. At small transverse momenta of the top-quark pair, the
logarithmically-enhanced QCD contributions are resummed to all orders up to
next-to-leading logarithmic accuracy. At intermediate and large values of
transverse momenta, the resummation is consistently combined with the complete
result at fixed perturbative order. We present numerical results for the
transverse-momentum distribution of top-quark pairs at LHC energies. We perform
a detailed study of the scale dependence of the results to estimate their
perturbative uncertainty. We comment on the comparison with ATLAS and CMS data.Comment: Few comments added. Version published on JHE
Ways of Development of Modern Urban Environment in the Context of Appropriation of Underground Spaces
Today, in many countries of the world, the appropriation of underground areas is directly related to urban planning and development. If, until now, the subsoil was considered a technical area through which the engineering and technical infrastructures passed, a new task is presented: to develop the principles of functional zoning of the given areas by the master plan of the city, which is considered in the article. The purpose of this article is to develop a method of systematic appropriation of underground areas, which will contribute to the solution of socio-economic problems in the context of urban development. During the research, a study of local and international experience was carried out, on the basis of which an analysis of the situation of underground and above-ground areas was developed in the context of the urban environment, on the example of Yerevan. A methodology was formed based on the principle of effectiveness of the interconnection of the discussed underground and above-ground areas and the application of new volume-spatial approaches
Top-quark pair hadroproduction at next-to-next-to-leading order in QCD
We report on a new calculation of the next-to-next-to-leading order (NNLO)
QCD radiative corrections to the inclusive production of top-quark pairs at
hadron colliders. The calculation is performed by using the subtraction
formalism to handle and cancel infrared singular contributions at intermediate
stages of the computation. We present numerical results for the total cross
section in collisions at TeV and TeV, and we compare
them with those obtained by using the publicly available numerical program
Top++. Our computation represents the first complete application of the
subtraction formalism to the hadroproduction of a colourful high-mass system at
NNLO.Comment: 9 pages, 1 figur
Heavy-quark mass effects in Higgs boson production at the LHC
We study the impact of heavy-quark masses in Higgs boson production through
gluon fusion at the LHC. We extend previous computations of the fully
differential cross section and of the transverse momentum spectrum of the Higgs
boson by taking into account the finite top- and bottom-quark masses up to
O(alpha_S^3). We also discuss the issues arising when the heavy-quark mass is
much smaller than the Higgs mass. Our results are implemented in updated
versions of the HNNLO and HRes numerical programs.Comment: Minor modifications, results unchanged. Discussion on uncertainties
added. Version published on JHE
Detection and development of a quantitation method for undeclared compounds in antidiabetic biologically active additives and its validation by high performance liquid chromatography
An isocratic, high-performance liquid chromatography (HPLC) quantitation method was developed for the quantitative determination of metformin, glibenclamide, gliclazide, glimepiride in some antidiabetic biologically active additives. A Nucleosil C18, 5 ÎĽm, 4.6 mm Ă— 150 mm, column with mobile phase containing buffer (10 mm Na2HPO4, 10 mm sodium dodecyl sulfate): acetonitrile = 68 : 32 (V/V), pH = 7.5 was used. The flow rate was 1.0 mL/min, and effluents were monitored at 226 nm. The retention times of gliclazide glibenclamide, glimepiride and metformin, were 2.203, 4.587, 5.667 and 10.182 min, respectively. Linearity was studied by preparing standard solutions of gliclazide, glibenclamide, glimepiride and metformin at the concentration range of 50% to 150% of working concentration from a stock solution. The method was successfully applied to the estimation of gliclazide, glibenclamide, glimepiride and metformin in some antidiabetic biologically active additives. This method was validated to confirm its system suitability, selectivity, linearity, precision and accuracy according to international conference on harmonization (ICH) guidelines
Prediction of health care expenditure increase: how does pharmacotherapy contribute?
Background
Rising health care costs are a major public health issue. Thus, accurately predicting future costs and understanding which factors contribute to increases in health care expenditures are important. The objective of this project was to predict patients healthcare costs development in the subsequent year and to identify factors contributing to this prediction, with a particular focus on the role of pharmacotherapy.
Methods
We used 2014–2015 Swiss health insurance claims data on 373′264 adult patients to classify individuals’ changes in health care costs. We performed extensive feature generation and developed predictive models using logistic regression, boosted decision trees and neural networks. Based on the decision tree model, we performed a detailed feature importance analysis and subgroup analysis, with an emphasis on drug classes.
Results
The boosted decision tree model achieved an overall accuracy of 67.6% and an area under the curve-score of 0.74; the neural network and logistic regression models performed 0.4 and 1.9% worse, respectively. Feature engineering played a key role in capturing temporal patterns in the data. The number of features was reduced from 747 to 36 with only a 0.5% loss in the accuracy. In addition to hospitalisation and outpatient physician visits, 6 drug classes and the mode of drug administration were among the most important features. Patient subgroups with a high probability of increase (up to 88%) and decrease (up to 92%) were identified.
Conclusions
Pharmacotherapy provides important information for predicting cost increases in the total population. Moreover, its relative importance increases in combination with other features, including health care utilisation