5,126 research outputs found
Non-perturbative Renormalization of the Complete Basis of Four-fermion Operators and B-parameters
We present results on the B-parameters , and , at
, with the tree-level Clover action. The renormalization of the
complete basis of dimension-six four-fermion operators has been performed
non-perturbatively. Our results for and are in reasonable
agreement with those obtained with the (unimproved) Wilson action. This is not
the case for . We also discuss some subtleties arising from a
recently proposed modified definition of the B-parameters.Comment: Talk presented at Lattice '97, Edinburgh (UK), July 1997. LaTeX 3
pages, uses espcrc
Matrix Elements without Quark Masses on the Lattice
We introduce a new parameterization of four-fermion matrix elements which
does not involve quark masses and thus allows a reduction of systematic
uncertainties in physical amplitudes. As a result the apparent quadratic
dependence of e'/e on m_s is removed. To simplify the matching between lattice
and continuum renormalization schemes, we express our results in terms of
Renormalization Group Invariant B-parameters which are renormalization-scheme
and scale independent. As an application of our proposal, matrix elements of
DeltaI=3/2 and SUSY DeltaF=2 () four-fermion operators have been
computed.Comment: LATTICE99(Matrix Elements), 3 pages, 1 figure, BUHEP-99-2
Introducing ORTO-R: a revision of ORTO-15. Based on the re-assessment of original data
Background: Orthorexia nervosa has attracted significant attention in the field, however, alongside increasing knowledge, more and more gaps are being identified. One of the fundamental problems concerns measurement of orthorexia nervosa. The most commonly used self-report measure, the ORTO-15, demonstrated an unstable factorial structure across different populations. Therefore, one might question whether the knowledge obtained from past research using ORTO-15 is valid or not. The aim of the present paper is to re-analyse original data used for the validation of ORTO-15 to assess its factorial structure and propose its revision, the ORTO-R. Methods: The description of the sample and procedure corresponds to the one reported in Donini et al. (Eat Weight Disord 10:28–32, 2005). N = 525 subjects were enrolled. To evaluate whether the factorial structure of ORTO-15, we used confirmatory factor analysis. The results revealed that the ORTO-15 indeed does not capture the structure of orthorexia nervosa adequately and revision is needed. The ORTO-R contains six items from ORTO-15, which were identified as the best markers of orthorexia nervosa. Discussion and conclusion: In the current paper, we present a refined measure of orthorexia nervosa—the ORTO-R. It is based on a frequently used ORTO-15, overcoming its main limitations. We strongly believe that the current work will act as a bridge, linking past with the future research, and that alongside a new measure, the field of research on orthorexia nervosa will move forward. Level of evidence: Level V, descriptive study
RI/MOM Renormalization Window and Goldstone Pole Contamination
We perform a comparative study of the ratio of lattice (Wilson fermion)
renormalization constants Z_P/Z_S, obtained non-perturbatively from the RI/MOM
renormalization conditions and from Ward Identities of on- and off-shell
Green's functions. The off-shell Ward Identity used in this work relies on
correlation functions with non-degenerate quark masses. We find that, due to
discretization effects, there is a 10-15% discrepancy between the two Ward
Identity determinations at current bare couplings (beta values). The RI/MOM
result is in the same range and has a similar systematic error of 10-15%. Thus,
contrary to a previous claim, the contamination of the RI/MOM result from the
presence of a Goldstone pole at scales of about 2 GeV is subdominant, compared
to finite cutoff effects.Comment: LATEX, 12 pages final version to appear on Phys. Lett.
Weak Matrix Elements without Quark Masses on the Lattice
We introduce a new parameterization of four-fermion matrix elements which
does not involve quark masses and thus allows a reduction of systematic
uncertainties in physical amplitudes. As a result the apparent quadratic
dependence of e'/e on m_s is removed. To simplify the matching between lattice
and continuum renormalization schemes, we express our results in terms of
Renormalization Group Invariant B-parameters which are renormalization-scheme
and scale independent. As an application of our proposal, matrix elements of
DeltaI=3/2 and SUSY DeltaF=2 (F=S,C,B) four-fermion operators have been
computed.Comment: Invited talk at QCD Euroconference 99, 4 pages BUHEP-99-2
Complexity Results for Modal Dependence Logic
Modal dependence logic was introduced recently by V\"a\"an\"anen. It enhances
the basic modal language by an operator =(). For propositional variables
p_1,...,p_n, =(p_1,...,p_(n-1);p_n) intuitively states that the value of p_n is
determined by those of p_1,...,p_(n-1). Sevenster (J. Logic and Computation,
2009) showed that satisfiability for modal dependence logic is complete for
nondeterministic exponential time. In this paper we consider fragments of modal
dependence logic obtained by restricting the set of allowed propositional
connectives. We show that satisfibility for poor man's dependence logic, the
language consisting of formulas built from literals and dependence atoms using
conjunction, necessity and possibility (i.e., disallowing disjunction), remains
NEXPTIME-complete. If we only allow monotone formulas (without negation, but
with disjunction), the complexity drops to PSPACE-completeness. We also extend
V\"a\"an\"anen's language by allowing classical disjunction besides dependence
disjunction and show that the satisfiability problem remains NEXPTIME-complete.
If we then disallow both negation and dependence disjunction, satistiability is
complete for the second level of the polynomial hierarchy. In this way we
completely classify the computational complexity of the satisfiability problem
for all restrictions of propositional and dependence operators considered by
V\"a\"an\"anen and Sevenster.Comment: 22 pages, full version of CSL 2010 pape
A speaker adaptive DNN training approach for speaker-independent acoustic inversion
We address the speaker-independent acoustic inversion (AI) problem, also referred to as acoustic-to-articulatory mapping. The scarce availability of multi-speaker articulatory data makes it difficult to learn a mapping which generalizes from a limited number of training speakers and reliably reconstructs the articulatory movements of unseen speakers. In this paper, we propose a Multi-task Learning (MTL)-based approach that explicitly separates the modeling of each training speaker AI peculiarities from the modeling of AI characteristics that are shared by all speakers. Our approach stems from the well known Regularized MTL approach and extends it to feed-forward deep neural networks (DNNs). Given multiple training speakers, we learn for each an acoustic-to-articulatory mapping represented by a DNN. Then, through an iterative procedure, we search for a canonical speaker-independent DNN that is "similar" to all speaker-dependent DNNs. The degree of similarity is controlled by a regularization parameter. We report experiments on the University of Wisconsin X-ray Microbeam Database under different training/testing experimental settings. The results obtained indicate that our MTL-trained canonical DNN largely outperforms a standardly trained (i.e., single task learning-based) speaker independent DNN
Delta M_K and epsilon_K in SUSY at the Next-to-Leading order
We perform a Next-to-Leading order analysis of Delta S=2 processes beyond the
Standard Model. Combining the recently computed NLO anomalous dimensions and
the B parameters of the most general Delta S=2 effective Hamiltonian, we give
an analytic formula for Delta M_K and epsilon_K in terms of the Wilson
coefficients at the high energy scale. This expression can be used for any
extension of the Standard Model with new heavy particles. Using this result, we
consider gluino-mediated contributions to Delta S=2 transitions in general SUSY
models and provide an improved analysis of the constraints on off-diagonal mass
terms between the first two generations of down-type squarks. Finally, we
improve the constraints on R-violating couplings from Delta M_K and epsilon_K.Comment: 20 pages, 1 figure, uses JHEP.cls; the magic numbers in eq. (2.7),
previously given in the basis (13) of hep-ph/9711402, are now given in the
basis (2.3) of this work. All numerical results are unchange
Renormalization Group Invariant Matrix Elements of DS = 2 and DI = 3/2 Four-Fermion Operators without Quark Masses
We introduce a new parameterization of four-fermion operator matrix elements
which does not involve quark masses and thus allows a reduction of systematic
uncertainties. In order to simplify the matching between lattice and continuum
renormalization schemes, we express our results in terms of renormalization
group invariant B-parameters which are renormalization-scheme and scale
independent. As an application of our proposal, matrix elements of DI=3/2 and
SUSY DS =2 operators have been computed. The calculations have been performed
using the tree-level improved Clover lattice action at two different values of
the strong coupling constant (beta=6/g^2=6.0 and 6.2), in the quenched
approximation. Renormalization constants and mixing coefficients of lattice
operators have been obtained non-perturbatively. Using lowest order ChiPT, we
also obtain ^{NDR}_{I=2} = (0.11\pm 0.02) GeV^4 and <Pi Pi|
O_8|K >^{NDR}_{I=2} = (0.51\pm 0.05) GeV^4 at mu=2 GeV.Comment: LATEX, 17 pages, 1 figure include
Inflammatory markers as prognostic factors of survival in patients affected by hepatocellular carcinoma undergoing transarterial chemoembolization
Transarterial chemoembolization (TACE) is a good choice for hepatocellular carcinoma (HCC) treatment when surgery and liver transplantation are not feasible. Few studies reported the value of prognostic factors influencing survival after chemoembolization. In this study, we evaluated whether preoperative inflammatory factors such as neutrophil to lymphocyte ratio and platelet to lymphocyte ratio affected our patient survival when affected by hepatocellular carcinoma. Methods. We retrospectively evaluated a total of 72 patients with hepatocellular carcinoma that underwent TACE. We enrolled patients with different etiopathogeneses of hepatitis and histologically proven HCC not suitable for surgery. The overall study population was dichotomized in two groups according to the median NLR value and was analyzed also according to other prognostic factors. Results. The global median overall survival (OS) was 28 months. The OS in patients with high NLR was statistically significantly shorter than that in patients with low NLR. The following pretreatment variables were significantly associated with the OS in univariate analyses: age, Child-Pugh score, BCLC stage, INR, and NLR. Pretreated high NLR was an independently unfavorable factor for OS. Conclusion. NLR could be considered a good prognostic factor of survival useful to stratify patients that could benefit from TACE treatment
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