Search results for "UMMA"
showing 10 items of 222 documents
Amorphous silica modeled with truncated and screened Coulomb interactions: A molecular dynamics simulation study
2007
We show that finite-range alternatives to the standard long-range BKS pair potential for silica might be used in molecular dynamics simulations. We study two such models that can be efficiently simulated since no Ewald summation is required. We first consider the Wolf method, where the Coulomb interactions are truncated at a cutoff distance r_c such that the requirement of charge neutrality holds. Various static and dynamic quantities are computed and compared to results from simulations using Ewald summations. We find very good agreement for r_c ~ 10 Angstroms. For lower values of r_c, the long--range structure is affected which is accompanied by a slight acceleration of dynamic properties…
Measurement of the tt¯ production cross section in the τ+jets final state in pp collisions at s=8 TeV using the ATLAS detector
2017
A measurement of the inclusive pp -> t (t) over bar + X production cross section in the tau + jets final state using only the hadronic decays of the tau lepton is presented. The measurement is p ...
Quantifying Artifacts in Ewald Simulations of Inhomogeneous Systems with a Net Charge
2014
Ewald summation, which has become the de facto standard for computing electrostatic interactions in biomolecular simulations, formally requires that the simulation box is neutral. For non-neutral systems the Ewald algorithm implicitly introduces a uniform background charge distribution that e ectively neutralizes the simulation box. Because a uniform distribution of counter charges typically deviates from the spatial distribution of counterions in real systems, artifacts may arise, in particular in systems with an inhomogeneous dielectric constant. Here we derive an analytical expression for the e ect of using an implicit background charge instead of explicit counterions, on the chemical po…
Sähköteknisen teollisuuden investointeihin vaikuttavat tekijät
2001
Prasības rakstura noteikšana un nozīmība Civilprocesā
2016
Autora izvēlētais bakalaura darba temats ir „Prasības rakstura noteikšana un nozīmība civilprocesā”. Ar prasības raksturu saprotams procesuāltiesisks prasību iedalījums mantiskās un nemantiskās prasībās. Šis iedalījums tiešā veidā ietekmē prasības nodrošināšanas iespējamību, valsts nodevas apmēru un attiecīgi arī tiesāšanās izdevumu piespriešanu, kā arī apmēru, kādā tiek atlīdzināti izdevumi advokāta palīdzības samaksai. Ņemot vērā konkrētas prasības rakstura definīcijas neesamību, praksē pastāv viedokļu dažādība par šī jēdziena izpratni. Līdz ar to nereti starp lietas dalībniekiem un tiesu domstarpības par prasības rakstura jēdziena izpratni. Tādēļ autors darbā izvirza mērķi izpētīt atšķir…
Del procedimento sommario di cognizione. Commento agli artt. 702bis-702quater
2021
Commento alle norme del codice di procedura civile che regolano il procedimento sommario di cognizione Commentary on the articles of Italian civil procedure code ruling summary proceeding
Character of sapropel properties based on its formation conditionsand possibilities of its use
2020
Tika pētītas sapropeļa īpašību un izmantošanas iespēju izmaiņas Latvijā. Tika izveidota saldūdens ezeru sapropeļa GIS datubāze un sapropeļa tipu klasifikācija. Trīs ezeru profilu izpēte tika īstenota izmantojot multidisciplināru pieeju. Lai rekonstruētu vides un klimata apstākļus, tika veikta nogulumu vecuma noteikšanu. Sapropeļa uzkrāšanās ir raksturīga ezeriem, kas veidojušies Augšpleistocēna nogulumos, kas ietekmē sapropeļa tipu. Sapropeļa veids un sastāvs atšķiras katras iegulas ietvaros un atkarīgs no ūdens ķīmiskā sastāva, dziļuma un temperatūras. Jaunākajos nogulumos ir augstāka metālu koncentrācijas, kas saistīts ar cilvēka darbības ietekmi. Atslēgvārdi: saldūdens sapropelis, gitija…
Exclusive radiative decays of W and Z bosons in QCD factorization
2015
We present a detailed theoretical analysis of very rare, exclusive hadronic decays of the electroweak gauge bosons V=W, Z from first principles of QCD. Our main focus is on the radiative decays V->M+gamma, in which M is a pseudoscalar or vector meson. At leading order in an expansion in powers of Lambda_{QCD}/m_V the decay amplitudes can be factorized into convolutions of calculable hard-scattering coefficients with the leading-twist light-cone distribution amplitude of the meson M. Power corrections to the decay rates arise first at order (Lambda_{QCD}/m_V)^2. They can be estimated in terms of higher-twist distribution amplitudes and are predicted to be tiny. We include one-loop O(alpha…
Factorization and N3LLp+NNLO predictions for the Higgs cross section with a jet veto
2013
We have recently derived a factorization formula for the Higgs-boson production cross section in the presence of a jet veto, which allows for a systematic resummation of large Sudakov logarithms of the form alpha_s^n ln^m(p_T^veto/m_H), along with the large virtual corrections known to affect also the total cross section. Here we determine the ingredients entering this formula at two-loop accuracy. Specifically, we compute the dependence on the jet-radius parameter R, which is encoded in the two-loop coefficient of the collinear anomaly, by means of a direct, fully analytic calculation in the framework of soft-collinear effective theory. We confirm the result obtained by Banfi et al. from a…
Top-pair forward-backward asymmetry beyond next-to-leading order
2011
We make use of recent results in effective theory and higher-order perturbative calculations to improve the theoretical predictions of the QCD contribution to the top-quark pair production forward-backward asymmetry at the Tevatron. In particular, we supplement the fixed-order next-to-leading order calculation with higher-order corrections from soft-gluon resummation at next-to next-to-leading order accuracy performed in two different kinematic schemes, which allows us to make improved predictions for the asymmetry in the $p\overline{p}$ and $t\overline{t}$ rest frames as a function of the rapidity and invariant mass of the $t\overline{t}$ pair. Furthermore, we provide binned results which …