Unbiased analysis of CLEO data at NLO and pion distribution amplitude

We discuss different QCD approaches to calculate the form factor F^{\gamma^*\gamma\pi}(Q^2) of the \gamma^*\gamma\to\pi^{0} transition giving preference to the light-cone QCD sum rules (LCSR) approach as being the most adequate. In this context we revise the previous analysis of the CLEO experimental data on F^{\gamma^*\gamma\pi}(Q^{2}) by Schmedding and Yakovlev. Special attention is paid to the sensitivity of the results to the (strong radiative) \alpha_s-corrections and to the value of the twist-four coupling \delta^2. We present a full analysis of the CLEO data at the NLO level of LCSRs, focusing particular attention to the extraction of the relevant parameters to determine the pion distribution amplitude, i.e., the Gegenbauer coefficients a_2 and a_4. Our analysis confirms our previous results and also the main findings of Schmedding and Yakovlev: both the asymptotic, as well as the Chernyak--Zhitnitsky pion distribution amplitudes are completely excluded by the CLEO data. A novelty of our approach is to use the CLEO data as a means of determining the value of the QCD vacuum non-locality parameter \lambda^2_q = / =0.4 GeV^2, which specifies the average virtuality of the vacuum quarks.Comment: 25 pages, 5 figures, 4 tables; format and margins corrected to fit page size; small changes in the text and correction of misprint

Findings to the flora of Russia and adjacent countries: New national and regional vascular plant records, 4

With this paper we continue a new annual series, the main purpose of which is to make significant floristic findings from Russia and neighboring countries more visible in Russia and abroad. In total, this paper presents new records for 48 vascular plant species from 6 Eurasian countries, obtained during field explorations, as well as during taxonomic revisions of herbarium materials. For the first time, a new locality of Leontopodium leiolepis is recorded for Russia, Rheum uzengukuushi for China, Rorippa prolifera for Lithuania, Lappula marginata for Kyrgyzstan and Tajikistan, Anthriscus caucalis, Chenopodium ficifolium, Euphorbia prostrata for Uzbekistan, Adonis × hybrida, Potamogeton × franconicus, Solidago × niederederi for the Asian part of Russia, Echinochloa esculenta, Poa jamalinensis, Puccinellia poecilantha for Siberia, Potentilla intermedia for the Caucasus, Rhynchospora alba for the Russian part of Altai, Poa sphondylodes, Veronica beccabunga for Eastern Siberia, Asclepias syriaca for the Republic of Altai, Chimaphila umbellata, Orobanche korshinskyi, Veronica scutellata for the Republic of Buryatia, Cirsium alatum, Thalictrum simplex for the Republic of Crimea, Thymus rariflorus, Th. terekensis for the Republic of Ingushetia, Berberis thunbergii, Crataegus maximowiczii, Prunus serotina for the Republic of Mordovia, Oenothera villosa for the Republic of Tatarstan, Astragalus sulcatus, Galium mollugo for the Republic of Tyva, Phragmites altissimus for the Chelyabinsk Region, Senecio dubitabilis for the Magadan Region, Asclepias syriaca, Galatella villosa, Potentilla recta for the Novosibirsk Region, Dodartia orientalis for the Omsk Region, Viola hultenii for the Sakhalin Region, Phragmites tzvelevii for the Samara Region and the Middle Volga, Jacobaea ferganensis for the Samara Region, Carex media, Impatiens parviflora for the Tyumen Region. There are some more findings which are not new for the region but they contribute significantly to the understanding of species distribution

Impact of Atherosclerosis- and Diabetes-Related Dicarbonyls on Vascular Endothelial Permeability: A Comparative Assessment

Background. Malondialdehyde (MDA), glyoxal (GO), and methylglyoxal (MGO) levels increase in atherosclerosis and diabetes patients. Recent reports demonstrate that GO and MGO cause vascular endothelial barrier dysfunction whereas no evidence is available for MDA. Methods. To compare the effects of MDA, GO, or MGO on endothelial permeability, we used human EA.hy926 endothelial cells as a standard model. To study cortical cytoplasm motility and cytoskeletal organization in endothelial cells, we utilized time-lapse microscopy and fluorescent microscopy. To compare dicarbonyl-modified protein band profiles in these cells, we applied Western blotting with antibodies against MDA- or MGO-labelled proteins. Results. MDA (150–250 μM) irreversibly suppressed the endothelial cell barrier, reduced lamellipodial activity, and prevented intercellular contact formation. The motile deficiency of MDA-challenged cells was accompanied by alterations in microtubule and microfilament organization. These detrimental effects were not observed after GO or MGO (250 μM) administration regardless of confirmed modification of cellular proteins by MGO. Conclusions. Our comparative study demonstrates that MDA is more damaging to the endothelial barrier than GO or MGO. Considering that MDA endogenous levels exceed those of GO or MGO and tend to increase further during lipoperoxidation, it appears important to reduce oxidative stress and, in particular, MDA levels in order to prevent sustained vascular hyperpermeability in atherosclerosis and diabetes patients

Use and Misuse of QCD Sum Rules in Heavy-to-light Transitions: the Decay B→ρeνB\to\rho e \nu Reexamined

The existing calculations of the form factors describing the decay $B\to\rho e \nu$ from QCD sum rules have yielded conflicting results at small values of the invariant mass squared of the lepton pair. We demonstrate that the disagreement originates from the failure of the short-distance expansion to describe the $\rho$ meson distribution amplitude in the region where almost the whole momentum is carried by one of the constituents. This limits the applicability of QCD sum rules based on the short-distance expansion of a three-point correlation function to heavy-to-light transitions and calls for an expansion around the light-cone, as realized in the light-cone sum rule approach. We derive and update light-cone sum rules for all the semileptonic form factors, using recent results on the $\rho$ meson distribution amplitudes. The results are presented in detail together with a careful analysis of the uncertainties, including estimates of higher-twist effects, and compared to lattice calculations and recent CLEO measurements. We also derive a set of ``improved'' three-point sum rules, in which some of the problems of the short-distance expansion are avoided and whose results agree to good accuracy with those from light-cone sum rules.Comment: 34 pages Latex; two references added; one typo in one table corrected; accepted for publication in Phys. Rev.

Observation of parametric X-rays produced by 400 GeV/c protons in bent crystals

Spectral maxima of parametric X-ray radiation (PXR) produced by 400 GeV/c protons in bent silicon crystals aligned with the beam have been observed in an experiment at the H8 external beam of the CERN SPS. The total yield of PXR photons was about 10-6 per proton. Agreement between calculations and the experimental data shows that the PXR kinematic theory is valid for bent crystals with sufficiently small curvature as used in the experiment. The intensity of PXR emitted from halo protons in a bent crystal used as a primary collimator in a circular accelerator may be considered as a possible tool to control its crystal structure, which is slowly damaged because of irradiation. The intensity distribution of PXR peaks depends on the crystal thickness intersected by the beam, which changes for different orientations of a crystal collimator. This dependence may be used to control crystal collimator alignment by analyzing PXR spectra produced by halo protons.peer-reviewe

ЭХОКАРДИОГРАФИЧЕСКИЕ ПРЕДИКТОРЫ НЕБЛАГОПРИЯТНЫХ КЛИНИЧЕСКИХ СОБЫТИЙ ПРИ СЕРДЕЧНОЙ НЕДОСТАТОЧНОСТИ С СОХРАННОЙ ФРАКЦИЕЙ ВЫБРОСА ЛЕВОГО ЖЕЛУДОЧКА В СОЧЕТАНИИ С СИНДРОМОМ ОБСТРУКТИВНОГО АПНОЭ ВО СНЕ

HighlightsRepeated hospitalizations occupy a special place in adverse clinical events in heart failure, currently representing one of the most powerful predictors of adverse outcomes in this group of patients. Echocardiographic parameters such as longitudinal myocardial deformation, displacement in the annulus of the tricuspid valve, and left atrial volume index can serve as predictors of hospitalization for cardiovascular diseases in patients with heart failure with preserved ejection fraction and obstructive sleep apnea. Abstract Aim. To study the prognostic role of individual echocardiographic parameters in heart failure with preserved ejection fraction (HFpEF) in patients with arterial hypertension and obstructive sleep apnea (OSA).Methods. The study included 59 men with hypertension and OSA (apnea/hypopnea index >15 per hour). At baseline all patients underwent a sleep study and echocardiography with an additional assessment of the global longitudinal strain (GLS). Upon inclusion in the study and after 12 months of follow-up, a 6-minute walk test was performed. After 12 months, the clinical course of the disease was retrospectively assessed. The criteria for an adverse clinical course were episodes of hospitalization for cardiovascular diseases, the development of paroxysmal atrial fibrillation or high-grade ventricular arrhythmias (III–V class according to Ryan), worsening of heart failure with a transition to a higher functional class according to NYHA.Results. Significant differences were found in several echocardiographic parameters between the groups of patients with and without hospitalizations within 12 months of follow-up: tricuspid annular plane systolic excursion (TAPSE) (p = 0.017), GLS (p = 0.005), left atrial volume index (LAVI) (p = 0.032). According to the regression analysis results, TAPSE, GLS and left ventricular ejection fraction make a statistically significant contribution to the probability of hospitalizations among the evaluated echocardiographic predictors.Conclusion. The results of the study allow us to consider certain echocardiographic parameters, in particular GLS, TAPSE and LAVI, as predictors of hospitalizations in patients with HFpEF and OSA.Основные положенияПовторные госпитализации занимают особое место в ряду клинических событий при хронической сердечной недостаточности, представляя в настоящее время один из наиболее мощных предикторов неблагоприятных исходов в этой группе. Эхокардиографические параметры – продольная деформация миокарда левого желудочка, величина смещения фиброзного кольца трикуспидального клапана и индекс объема левого предсердия – служат предикторами госпитализации в стационар по поводу сердечно-сосудистых заболеваний у больных сердечной недостаточностью с сохранной фракцией выброса и синдромом обструктивного апноэ во сне. РезюмеЦель. Изучить прогностическую роль отдельных эхокардиографических параметров при сердечной недостаточности с сохранной фракцией выброса у больных артериальной гипертензией и синдромом обструктивного апноэ во сне (СОАС).Материалы и методы. В исследование включено 59 мужчин с артериальной гипертензией и СОАС (с индексом апноэ/гипопноэ >15 в час). Всем пациентам при включении в исследование выполнены полисомнографическое исследование и эхокардиография с дополнительной оценкой глобальной продольной деформации миокарда левого желудочка (GLS). При включении в исследование и через 12 мес. наблюдения проведен тест 6-минутной ходьбы. Через 12 мес. ретроспективно оценен характер клинического течения заболевания. Критериями неблагоприятного течения являлись эпизоды госпитализации в стационар по поводу сердечно-сосудистых заболеваний, развитие пароксизмальной фибрилляции предсердий или регистрация желудочковых нарушений ритма высоких градаций (III–V класса по Ryan), ухудшение хронической сердечной недостаточности с переходом в более высокий функциональный класс по NYHA.Результаты. Обнаружены значимые различия между группами пациентов с наличием и отсутствием госпитализаций в течение 12 мес. наблюдения по ряду эхокардиографических параметров: систолическому смещению фиброзного кольца трикуспидального клапана (TAPSE) (p = 0,017), GLS (p = 0,005) и индексу объема левого предсердия (p = 0,032). По результатам регрессионного анализа, статистически значимый вклад в вероятность госпитализаций среди оцениваемых эхокардиографических предикторов вносят TAPSE, GLS и фракция выброса левого желудочка.Заключение. Результаты исследования позволяют рассматривать отдельные эхокардиографические параметры, в частности GLS, TAPSE и индекс объема левого предсердия, в качестве предикторов госпитализаций у больных сердечной недостаточностью с сохранной фракцией выброса и СОАС