Precision measurement of the neutral pion lifetime.

The explicit breaking of the axial symmetry by quantum fluctuations gives rise to the so-called axial anomaly. This phenomenon is solely responsible for the decay of the neutral pion π0 into two photons (γγ), leading to its unusually short lifetime. We precisely measured the decay width Γ of the [Formula: see text] process. The differential cross sections for π0 photoproduction at forward angles were measured on two targets, carbon-12 and silicon-28, yielding [Formula: see text], where stat. denotes the statistical uncertainty and syst. the systematic uncertainty. We combined the results of this and an earlier experiment to generate a weighted average of [Formula: see text] Our final result has a total uncertainty of 1.50% and confirms the prediction based on the chiral anomaly in quantum chromodynamics.

Method for Simultaneous Prediction of Atomic Structure and Stability of Nanoclusters in a Wide Area of Compositions.

We present a universal method for the large-scale prediction of the atomic structure of clusters. Our algorithm performs the joint evolutionary search for all clusters in a given area of the compositional space and takes advantage of structural similarities frequently observed in clusters of close compositions. The resulting speedup is up to 50 times compared to current methods. This enables first-principles studies of multicomponent clusters with full coverage of a wide range of compositions. As an example, we report an unprecedented first-principles global optimization of 315 Si nO m clusters with n ≤ 15 and m ≤ 20. The obtained map of Si-O cluster stability shows the existence of both expected (SiO2) n and unexpected (e.g., Si4O18) stable (magic) clusters, which can be important for a variety of applications.

The impact of electron correlations on the energetics and stability of silicon nanoclusters.

The first-principles prediction of stable nanocluster structure is often hampered by the existence of many isomer configurations with energies close to the ground state. This fact attaches additional importance to many-electron effects beyond density functional theory (DFT), because their contributions can change a subtle energy order of competitive structures. To analyze this problem, we consider, as an example, the energetics of silicon nanoclusters passivated by hydrogen Si10H2n (0 ≤ n ≤ 11), where passivation changes the structure from compact to loosely packed and branched. Our calculations performed with DFT, hybrid functionals, and Hartree-Fock methods, as well as by the GW approximation, confirm a considerable sensitivity of isomer energy ordering to many-electron effects.

[Possible side effects of drugs in elderly patients with chronic obstructive pulmonary disease and comorbidity].

the papers gives data on the positive effects and adverse reactions of drugs used to treat chronic obstructive pulmonary disease (COPD) and its comorbidity, first of all cardiovascular disease. The authors present alternative points of views based on both the data available in the literature and their findings. they propose to modify pharmacotherapy for COPD in the presence of comorbidity in patients of old age groups.

[Problems of Diagnosis and Treatment of Pulmonary Hypertension in Old Patients With Chronic Obstructive Pulmonary Disease].

The article contains consideration of risk factors of pulmonary hypertension (PH), clinical states associated with PH, and effect of age on susceptibility to PH in patients with chronic obstructive pulmonary disease (COPD). We have analyzed the prevalence of PH associated with COPD, its importance in the structure of diseases in patients of older age groups. Frequency of PH in old patients is associated with prevalence of concomitant diseases. Addition of LH to polymorbid complex of old age worsens quality of life and increases mortality. We also present in this article data on the use of modern drugs for the treatment of LH in COPD patients aged 60 years and older.

Regional specifics of microbial landscape in outpatients with lower respiratory tract infections.

BACKGROUND: The last years have witnessed progressive growth of antimicrobial resistance (AMR) both in hospital-acquired and community-acquired respiratory infections. Regional guidelines (2006) presented standard approaches to pharmacotherapy and provided an important contribution to improvement of antimicrobial therapy at healthcare facilities of both the City of Stavropol and the Stavropol Region. At the same time, recent years have witnessed substantial changes in sensitivity to antimicrobials; besides, newer antibiotics have become available now. This substantiates the need for update of the regional guidelines [1]. OBJECTIVE: To determine the issues related to standardization of antibiotic therapy of lower respiratory tract (LRT) infections at an outpatient setting; to assess regional changes (2007-2012) in the spectrum of pathogens causing LRT diseases in patients of the regional healthcare facilities in view of their age and the diagnosis as compared with the years of 2003-2006. METHODS: In 2007-2012, we examined sputum microbiology of patients with LRT infections at the bacteriological laboratory of the Centre for Clinical Pharmacology and Pharmacotherapy (Stavropol, Russia), following the methodology guidelines [2]. The comparison was carried out with the results of the microbiological examination of 7051 sputum samples (held in 2003-2006). Statistical analysis was carried out using arithmetic means, standard errors, and Student's t test involving a software package STATISTICA 6.0. RESULTS: In the outpatient practice, half of the patients with LRT infections were identified to have Str. Pneumoniae. The sputum of every fifth examined patient allowed isolating Enterobacteriaceae family members such as Klebsiella spp. (Klebsiella pneumoniae in most cases), Serratiaspp., E. coli, and Enterobacter spp. It is essential to note that almost a quarter of the patients were found to have M. pneumoniae. C. Pneumonia was detected quite often as well (19%). Str. pneumoniae, M. pneumoniae, and C. pneumoniae were found in virtually 80% of all the cases of community-acquired pneumonia in adults. H. influenzae and M. pneumoniae were 2-3 times more often isolated from the sputum of patients with chronic obstructive pulmonary disease (COPD) and chronic non-obstructive bronchitis.Along with an increase in the patients' age, regardless of the diagnosis, the proportion of pneumococci, Haemophilus influenzae and various members of the Enterobacteriaceae family went up, while the share of mycoplasmas went down. However, even in patients over 60 years of age M. pneumoniae accounted for a significant share in the overall spectrum of pathogens, which indicates the need for microbiological monitoring, especially as far as COPD is concerned.In contrast to the previous years, only 35% of the patients (previously 60%) underwent bacteriological examination (p<0.05) while receiving antibiotic therapy. Significant prevalence of mycoplasmas in the structure of the isolated microorganisms was found in patients who had been previously treated with ß-lactam antibiotics.Associations of pathogens were detected in 14% of cases, which is half the rate found 2-3 years ago. The associations were found to reveal more frequent presence of H. influenzae in patients with acute exacerbation of chronic non-obstructive bronchitis, and Enterobacteriaceae - in patients with COPD and pneumonia. The recent years have shown that, combined with other microorganisms, there can be detected pneumococci (p<0.05), H. influenzae, as well M. pneumoniae, while there have been fewer cases of enterococci and enterobacteria; as for non-filterable bacteria, they have been never detected again (p<0.05).Strains of H. influenzae maintained high sensitivity to aminopenicillins, including the protected ones. The antibiotic resistance possessed by Str. pneumoniae to aminopenicillins doubled (12.4% strains vs. 6.4% 3 years ago, p<0.05). The resistance to Co-trimoxazole and Ofloxacin was 27.9% and to macrolides it was 17.9%. Various representatives of the Enterobacteriaceae family maintained high sensitivity to aminopenicillins, second and third generation cephalosporins, fluoroquinolones.Of the 20 M. pneumoniae strains that were tested, 8 (40%) displayed resistance to one or more antimicrobials. The highest numbers of cases with resistance were detected to Ciprofloxacin (25%) and Erythromycin (20%). 10% strains of mycoplasma showed resistance to Doxycycline and Ofloxacin, while only 5% of mycoplasmas were identified as having non-sensitivity to Clarithromycin and Azithromycin. CONCLUSIONS: The results of the research carried out in the recent years in comparison with the data of the previous years, call for reviewing of the standard approaches to the choice of antimicrobial agents in respiratory tract infections. In order to improve the standard of care, the choice of medicines should be based on a number of factors, namely the age, the severity of the respective pathological condition, previous antimicrobial use, and the level of care.

[Microflora of palatine tonsils in chronic tonsillitis].

The objective of the present work was to develop the standardized approaches to pharmacotherapy of chronic tonsillitis based on the data of regional specificity of the tonsillar microflora. The methods of investigations included the study of throat swabs obtained from 668 patients presenting with various forms of chronic tonsillitis (CT). Half of these patients were shown to be infected with Streptococcus pyogenes and 24.5% with Mycoplasma pneumoniae. The presence of concomitant pathology of the respiratory and digestive tracts in the patients with CT increases the probability of identification of enterobacteria, enteroccocci, and staphylococci in combination with streptococci and mycoplasmas. It is concluded that the choice of antibacterial therapy should be based on the results of analysis of the aggravated medical history and bacteriological diagnostics including the isolation of all putative pathogens and examination of their susceptinility to antibacterial agents.

[Adrenalectomy changes diazepam performance in male and female rats under multiparametric test conditions].

It is established that adrenalectomy decreases the "sedative" and "anti-anxiety" effects and reduces the "anxiogenic" effect of diazepam in male rats under multiparametric test conditions. At the same time, the "sedative" and "activating" effects of this tranquilizer do not appear in adrenalectomized female rats and the "anti-anxiety" effect is only observed in the evening. The "anxiogenic" effect of diazepam in females is not observed for a drug dose of 0.5 mg/kg and is only manifested at a dose of 0.1 mg/kg.

[Stress effect on haloperidol-induced catalepsy and its circadian rhythm in intact and ovariectomized female rats].

Stressing reduces the intensity of haloperidol-induced catalepsy in intact female rats and increases it in ovariectomized animals. Ovarioectomy reduces the severity of haloperidol catalepsy. Circadian rhythm acrophase of the cataleptogenic haloperidol activity in female rats after ovariectomy and stress exhibits significant displacement.

Emission characteristics of H- ion source with inverse gas magnetron geometry.

The work is dedicated to the experimental investigation of the intense volume-plasma H(-) ion source. Preliminary experimental researches of two parameters of the upgraded source--emission density of H(-) ions and gas flow--are represented below. In plasma volume of noncesium H(-) ion source, the conditions for obtaining of increased density of H(-) ions in the field of adjoining to the emission aperture were realized. The advancing of electrode system of the emission chamber of a source has allowed receiving the value of an emission density of H(-) ions equal to 600 mA/cm(2).

[Sexual distinctions of the diazepam activity in rats in the conflict situation].

Diazepam caused less pronounced shifts in the conflict situation test in female rats as compared to males. The drug produced more pronounced anticonflict action on male rats in the evening. In female rats, a doze of 0.5 mg/kg of the anxiolytic drug produced a clear anticonflict action, mostly in the evening; however, even this effect was approximately only about half of that observed in males in the same period of time.

[Chronobiological distinctions in swimming behaviour of intact and ovariectomised rats females].

The forced swimming (experimental model of depression) of intact and ovarioectomized rats-females using chronobiological approach was investigated. "The index of depression" of intact rats-females in a stage of proestrus/estrus was a little higher than in diestrus 1/2 in the morning and evening was established. Thus "the index of depression" in evening time was great. "The index of depression" of female in condition of diestrus 1/2 in the evening was lower in comparison with morning hours, and in a phase proestrus/estrus it was higher in the evening. "The index of depression" of ovarioectomized females in comparison with intact rats, both in the morning and in the evening, was higher. Thus the parameter of ovario-ectomized females in the evening was lesser than in the morning. However, in comparison with intact females the change of "the index of depression" in ovario-ectomized females in the evening was lesser than in the morning.

Measurement of the tensor structure function b1 of the deuteron.

The Hermes experiment has investigated the tensor spin structure of the deuteron using the 27.6 GeV/c positron beam of DESY HERA. The use of a tensor-polarized deuteron gas target with only a negligible residual vector polarization enabled the first measurement of the tensor asymmetry A(d)zz and the tensor structure function b(d)1 for average values of the Bjorken variable 0.01< <0.45 and of the negative of the squared four-momentum transfer 0.5 GeV2 < <5 GeV2. The quantities A(d)zz and b(d)1 are found to be nonzero. The rise of b(d)1 for decreasing values of x can be interpreted to originate from the same mechanism that leads to nuclear shadowing in unpolarized scattering.

The effects of lesions to the striatum on the function of the hypothalamo-hypophyseal-adrenal system in adrenalectomized rats.

Experiments on white rats were performed to study the effects of bilateral lesioning of the striatum on activation of the hypothalamo-hypophyseal-adrenal system (HHAS) after unilateral adrenalectomy. These studies showed that increases in the weight of the surviving adrenal gland were smaller in striatectomized rats than in controls. There was a significant decrease in corticosteroid production by the intact gland. These changes were most marked after destruction of the dorsal parts of the nucleus. These data provide evidence for involvement of the striatum in controlling HHAS activity via a feedback mechanism.

Flavor decomposition of the sea-quark helicity distributions in the nucleon from semiinclusive deep inelastic scattering.

Double-spin asymmetries of semiinclusive cross sections for the production of identified pions and kaons have been measured in deep inelastic scattering of polarized positrons on a polarized deuterium target. Five helicity distributions including those for three sea quark flavors were extracted from these data together with reanalyzed previous data for identified pions from a hydrogen target. These distributions are consistent with zero for all three sea flavors. A recently predicted flavor asymmetry in the polarization of the light quark sea appears to be disfavored by the data.

Evidence for quark-hadron duality in the proton spin asymmetry A1.

Spin-dependent lepton-nucleon scattering data have been used to investigate the validity of the concept of quark-hadron duality for the spin asymmetry A1. Longitudinally polarized positrons were scattered off a longitudinally polarized hydrogen target for values of Q2 between 1.2 and 12 GeV2 and values of W2 between 1 and 4 GeV2. The average double-spin asymmetry in the nucleon resonance region is found to agree with that measured in deep-inelastic scattering at the same values of the Bjorken scaling variable x. This finding implies that the description of A1 in terms of quark degrees of freedom is valid also in the nucleon resonance region for values of Q2 above 1.6 GeV2.

Q2 dependence of nuclear transparency for exclusive rho0 production.

Exclusive coherent and incoherent electroproduction of the rho(0) meson from 1H and 14N targets has been studied at the HERMES experiment as a function of coherence length (l(c)), corresponding to the lifetime of hadronic fluctuations of the virtual photon, and squared four-momentum of the virtual photon (-Q2). The ratio of 14N to 1H cross sections per nucleon, called nuclear transparency, was found to increase (decrease) with increasing l(c) for coherent (incoherent) rho(0) electroproduction. For fixed l(c), a rise of nuclear transparency with Q2 is observed for both coherent and incoherent rho(0) production, which is in agreement with theoretical calculations of color transparency.

n-p short-range correlations from (p,2p+n) measurements.

We studied the 12C(p,2p+n) reaction at beam momenta of 5.9, 8.0, and 9.0 GeV/c. For quasielastic (p,2p) events p(f), the momentum of the knocked-out proton before the reaction, was compared (event by event) with p(n), the coincident neutron momentum. For |p(n)|>k(F)=0.220 GeV/c (the Fermi momentum) a strong back-to-back directional correlation between p(f) and p(n) was observed, indicative of short-range n-p correlations. From p(n) and p(f) we constructed the distributions of c.m. and relative motion in the longitudinal direction for correlated pairs. We also determined that 49+/-13% of events with |p(f)|>k(F) had directionally correlated neutrons with |p(n)|>k(F).