321 research outputs found
General one-loop formulas for decay
Radiative corrections to the are evaluated in the
one-loop approximation. The unitary gauge gauge is used. The analytic result is
expressed in terms of the Passarino-Veltman functions. The calculations are
applicable for the Standard Model as well for a wide class of its gauge
extensions. In particular, the decay width of a charged Higgs boson can be derived. The consistence of our formulas and
several specific earlier results is shown.Comment: 33 pages, 3 figures, a new section (V) and references were improved
in the published versio
The K\"ahler-Ricci flow with positive bisectional curvature
We show that the K\"ahler-Ricci flow on a manifold with positive first Chern
class converges to a K\"ahler-Einstein metric assuming positive bisectional
curvature and certain stability conditions.Comment: 15 page
The LQG -- String: Loop Quantum Gravity Quantization of String Theory I. Flat Target Space
We combine I. background independent Loop Quantum Gravity (LQG) quantization
techniques, II. the mathematically rigorous framework of Algebraic Quantum
Field Theory (AQFT) and III. the theory of integrable systems resulting in the
invariant Pohlmeyer Charges in order to set up the general representation
theory (superselection theory) for the closed bosonic quantum string on flat
target space. While we do not solve the, expectedly, rich representation theory
completely, we present a, to the best of our knowledge new, non -- trivial
solution to the representation problem. This solution exists 1. for any target
space dimension, 2. for Minkowski signature of the target space, 3. without
tachyons, 4. manifestly ghost -- free (no negative norm states), 5. without
fixing a worldsheet or target space gauge, 6. without (Virasoro) anomalies
(zero central charge), 7. while preserving manifest target space Poincar\'e
invariance and 8. without picking up UV divergences. The existence of this
stable solution is exciting because it raises the hope that among all the
solutions to the representation problem (including fermionic degrees of
freedom) we find stable, phenomenologically acceptable ones in lower
dimensional target spaces, possibly without supersymmetry, that are much
simpler than the solutions that arise via compactification of the standard Fock
representation of the string. Moreover, these new representations could solve
some of the major puzzles of string theory such as the cosmological constant
problem. The solution presented in this paper exploits the flatness of the
target space in several important ways. In a companion paper we treat the more
complicated case of curved target spaces.Comment: 46 p., LaTex2e, no figure
Bergman kernel and complex singularity exponent
We give a precise estimate of the Bergman kernel for the model domain defined
by where
is a holomorphic map from to ,
in terms of the complex singularity exponent of .Comment: to appear in Science in China, a special issue dedicated to Professor
Zhong Tongde's 80th birthda
The K\"ahler-Ricci flow on surfaces of positive Kodaira dimension
The existence of K\"ahler-Einstein metrics on a compact K\"ahler manifold has
been the subject of intensive study over the last few decades, following Yau's
solution to Calabi's conjecture. The Ricci flow, introduced by Richard Hamilton
has become one of the most powerful tools in geometric analysis.
We study the K\"ahler-Ricci flow on minimal surfaces of Kodaira dimension one
and show that the flow collapses and converges to a unique canonical metric on
its canonical model. Such a canonical is a generalized K\"ahler-Einstein
metric. Combining the results of Cao, Tsuji, Tian and Zhang, we give a metric
classification for K\"aher surfaces with a numerical effective canonical line
bundle by the K\"ahler-Ricci flow. In general, we propose a program of finding
canonical metrics on canonical models of projective varieties of positive
Kodaira dimension
EVALUATION OF EFFECTIVENESS OF ANTIVIRAL THERAPY FOR CHRONIC HEPATITIS C, CAUSED BY HCV GENOTYPE 6
Objectives: Evaluating the effectiveness of 2 therapeutic schemes for chronic hepatitis C (genotype 6) which combined sofosbuvir and ribavirin, one of them also included pegylated interferon. Materials and methods: The study included 110 patients with chronic hepatitis C (genotype 6), who have undergone antiviral therapy (HTP) in Hepatology Clinic inHo Chi Minh City,Vietnamfrom November 2015 to July 2016. 24 patients were treated by Pegylated interferon alfa-2a, ribavirin and sofosbuvir for 12 weeks, 86 patients – by sofosbuvir and ribavirin for 24 weeks. Non-interferon regimen was administered primarily to patients with contraindications to the use of interferon. To monitor the effectiveness of antiviral therapy, quantification of HCV RNA in serum was performed by PCR prior to treatment, at 4th, 12th or 24th week (depending on the observation group) from the starting of treatment and at 12th, 24th week after completion of treatment. Results: All patients, who were treated with pegylated interferon, ribavirin and sofosbuvir, completed the full course of treatment and 100% of them are registered with sustained virological response at 12th and 24th week after the end of antiviral therapy (SVR-12 and SVR-24, respectively). In the group of patients, who treated with ribavirin and sofosbuvir, 97,7% of patients completed full course of treatment (SVR-12 was registered in 93% of patients, and SVR-24 – in 91,9% of patients). Of 75 patients without a history of HCC, SVR24 was registered in 74 people (98,7%), of 11 patients with HCC – in 5 patients (45,5%). SVR-24 was registered in 98% of patients with cirrhosis (F4) without HCC. Conclusion: The results can serve as a justification for the use of these schemes of antiviral therapy for special groups of patients and/or conditions when it is impossible to follow the latest recommendations, which will help to expand the access of patients to effective antiviral therapy for chronic hepatitis C
First detection of a Vssc allele V1016G conferring a high level of insecticide resistance in Aedes albopictus collected from Europe (Italy) and Asia (Vietnam), 2016. A new emerging threat to controlling arboviral diseases
Introduction
Aedes albopictus (Skuse) is an important vector of arboviral diseases, including dengue, chikungunya and Zika virus disease. Monitoring insecticide resistance and mechanisms by which the mosquito develops resistance is crucial to minimise disease transmission.
Aim
To determine insecticide resistance status and mechanisms in Ae. albopictus from different geographical regions.
Methods
We sampled 33 populations of Ae. albopictus from Asia, Europe and South America, and tested these for susceptibility to permethrin, a pyrethroid insecticide. In resistant populations, the target site for pyrethroids, a voltage-sensitive sodium channel (Vssc) was genotyped. Three resistant sub-strains, each harbouring a resistance allele homozygously, were established and susceptibilities to three different pyrethroids (with and without a cytochrome P450 inhibitor) were assayed.
Results
Most populations of Ae. albopictus tested were highly susceptible to permethrin but a few from Italy and Vietnam (4/33), exhibited high-level resistance. Genotyping studies detected a knockdown resistance (kdr) allele V1016G in Vssc for the first time in Ae. albopictus. Two previously reported kdr alleles, F1534C and F1534S, were also detected. The bioassays indicated that the strain homozygous for the V1016G allele showed much greater levels of pyrethroid resistance than other strains harbouring F1534C or F1534S.
Conclusion
The V1016G allele was detected in bothAsian and Italian Ae. albopictus populations, thus a spread of this allele beyond Italy in Europe cannot be ruled out. This study emphasises the necessity to frequently and regularly monitor the V1016G allele in Ae. albopictus, particularly where this mosquito species is the main vector of arboviruses
Intensified Antituberculosis Therapy in Adults with Tuberculous Meningitis
BACKGROUND
Tuberculous meningitis is often lethal. Early antituberculosis treatment and adjunctive treatment with glucocorticoids improve survival, but nearly one third of patients with the condition still die. We hypothesized that intensified antituberculosis treatment would enhance the killing of intracerebral Mycobacterium tuberculosis organisms and decrease the rate of death among patients.
METHODS
We performed a randomized, double-blind, placebo-controlled trial involving human immunodeficiency virus (HIV)-infected adults and HIV-uninfected adults with a clinical diagnosis of tuberculous meningitis who were admitted to one of two Vietnamese hospitals. We compared a standard, 9-month antituberculosis regimen (which included 10 mg of rifampin per kilogram of body weight per day) with an intensified regimen that included higher-dose rifampin (15 mg per kilogram per day) and levofloxacin (20 mg per kilogram per day) for the first 8 weeks of treatment. The primary outcome was death by 9 months after randomization.
RESULTS
A total of 817 patients (349 of whom were HIV-infected) were enrolled; 409 were randomly assigned to receive the standard regimen, and 408 were assigned to receive intensified treatment. During the 9 months of follow-up, 113 patients in the intensified-treatment group and 114 patients in the standard-treatment group died (hazard ratio, 0.94; 95% confidence interval, 0.73 to 1.22; P=0.66). There was no evidence of a significant differential effect of intensified treatment in the overall population or in any of the subgroups, with the possible exception of patients infected with isoniazid-resistant M. tuberculosis. There were also no significant differences in secondary outcomes between the treatment groups. The overall number of adverse events leading to treatment interruption did not differ significantly between the treatment groups (64 events in the standard-treatment group and 95 events in the intensified-treatment group, P=0.08).
CONCLUSIONS
Intensified antituberculosis treatment was not associated with a higher rate of survival among patients with tuberculous meningitis than standard treatment. (Funded by the Wellcome Trust and the Li Ka Shing Foundation; Current Controlled Trials number, ISRCTN61649292.)
Numerical Hermitian Yang-Mills Connections and Kahler Cone Substructure
We further develop the numerical algorithm for computing the gauge connection
of slope-stable holomorphic vector bundles on Calabi-Yau manifolds. In
particular, recent work on the generalized Donaldson algorithm is extended to
bundles with Kahler cone substructure on manifolds with h^{1,1}>1. Since the
computation depends only on a one-dimensional ray in the Kahler moduli space,
it can probe slope-stability regardless of the size of h^{1,1}. Suitably
normalized error measures are introduced to quantitatively compare results for
different directions in Kahler moduli space. A significantly improved numerical
integration procedure based on adaptive refinements is described and
implemented. Finally, an efficient numerical check is proposed for determining
whether or not a vector bundle is slope-stable without computing its full
connection.Comment: 38 pages, 10 figure
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