The Spin Structure of a Polarized Photon

We show that the first moment of the spin-dependent structure function $g_1^{\gamma}(x,Q^2)$ of a real photon vanishes independent of the momentum transfer $Q^2$ it is probed with. This result is non-perturbative: it holds to all orders in perturbation theory in abelian and non-abelian gauge theory and at every twist.Comment: LaTex, 13 page

Flavor separation of the Boer-Mulders function from unpolarized π−p\pi^- p and π−D\pi^- D Drell-Yan processes

We show that measuring the $\cos 2\phi$ angular dependence in unpolarized Drell-Yan processes with $\pi^-$ beams colliding on proton and deuteron targets can determine the ratio of the Boer-Mulders functions for $d$ and $u$ quarks inside the proton $h_1^{\perp,d}/h_1^{\perp,u}$, which is still lack of theoretical constraint. The comparison of the $\cos 2 \phi$ asymmetries measured in unpolarized $\pi^- p$ and $\pi^- D$ Drell-Yan processes, which are accessible at CERN by the COMPASS collaboration, can help to discriminate whether $h_1^\perp$ effects or QCD vacuum effects are preferred by data.Comment: 10 pages, 2 figures, published in Physics Letters

T-odd quark-gluon-quark correlation function in the diquark model

We study the transverse momentum dependent quark-gluon-quark correlation function. Using a spectator diquark model, we calculate the eight time-reversal-odd interaction-dependent twist-3 quark distributions appearing in the decomposition of the transverse momentum dependent quark-gluon-quark correlator. In order to obtain finite results, we assume a dipole form factor for the nucleon-quark-diquark coupling, instead of a point-like coupling. The results are compared with the time-reversal-odd interaction-independent twist-3 TMDs calculated in the same model.Comment: References and figure added, version published in PL

Upgrading the ECR ion source within FAMA

Recent upgrading of the Facility for Modification and Analysis of Materials with Ion Beams-FAMA, in the Laboratory of Physics of the Vinca Institute of Nuclear Sciences, included the modernization of its electron cyclotron resonance ion source. Since the old ion source was being extensively used for more than 15 years for production of multiply charged ions from gases and solid substances, its complete reconstruction was needed. The main goal was to reconstruct its plasma and injection chambers and magnetic structure, and thus intensify the production of multiply charged ions. Also, it was decided to refurbish its major subsystems the vacuum system, the microwave system, the gas inlet system, the solid substance inlet system, and the control system. All these improvements have resulted in a substantial increase of ion beam currents, especially in the case of high charge states, with the operation of the ion source proven to be stable and reproducible

Upgrading of the CAPRICE type ECR ion source

The CAPRICE-type ECR ion source mVINIS has been upgraded by increasing its magnetic field to improve a plasma confinement and thereby enhance the source performance. This modification made it also possible to increase the internal diameter of the plasma chamber and to replace the coaxial microwave input by a waveguide. Some major subsystems such as: the vacuum system, the microwave system, the gas inlet system, the solid substance inlet system, and the control system have been also refurbished. All these improvements have resulted in a substantial increase of ion beam currents, especially in the case of high charge states, with the operation of the ion source proven to be stable and reproducible. This modification can be applied to other CAPRICE-type ion sources. © 2018 Author(s).17th International Conference on Ion Sources 2018; Geneva's International Conference Centre Geneva; Switzerland; 15 September 2017 through 20 September 2017; Code 13992

Azimuthal Spin Asymmetries of Pion Electroproduction

Azimuthal spin asymmetries, both for charged and neutral pion production in semi-inclusive deep inelastic scattering of unpolarized charged lepton beams on longitudinally and transversely polarized nucleon targets, are analyzed and calculated. Various assumptions and approximations in the quark distributions and fragmentation functions often used in these calculations are studied in detail. It is found that different approaches to the distribution and fragmentation functions may lead to quite different predictions on the azimuthal asymmetries measured in the HERMES experiments, thus their effects should be taken into account before using the available data as a measurement of quark transversity distributions. It is also found that the unfavored quark to pion fragmentation functions must be taken into account for $\pi^-$ production from a proton target, although they can be neglected for $\pi^+$ and $\pi^0$ production. Pion production from a proton target is suitable to study the $u$ quark transversity distribution, whereas a combination of pion production from both proton and neutron targets can measure the flavor structure of quark transversity distributions.Comment: 31 latex pages, 13 figure, to appear in PR

Snake Cytotoxins Bind to Membranes via Interactions with Phosphatidylserine Head Groups of Lipids

The major representatives of Elapidae snake venom, cytotoxins (CTs), share similar three-fingered fold and exert diverse range of biological activities against various cell types. CT-induced cell death starts from the membrane recognition process, whose molecular details remain unclear. It is known, however, that the presence of anionic lipids in cell membranes is one of the important factors determining CT-membrane binding. In this work, we therefore investigated specific interactions between one of the most abundant of such lipids, phosphatidylserine (PS), and CT 4 of Naja kaouthia using a combined, experimental and modeling, approach. It was shown that incorporation of PS into zwitterionic liposomes greatly increased the membrane-damaging activity of CT 4 measured by the release of the liposome-entrapped calcein fluorescent dye. The CT-induced leakage rate depends on the PS concentration with a maximum at approximately 20% PS. Interestingly, the effects observed for PS were much more pronounced than those measured for another anionic lipid, sulfatide. To delineate the potential PS binding sites on CT 4 and estimate their relative affinities, a series of computer simulations was performed for the systems containing the head group of PS and different spatial models of CT 4 in aqueous solution and in an implicit membrane. This was done using an original hybrid computational protocol implementing docking, Monte Carlo and molecular dynamics simulations. As a result, at least three putative PS-binding sites with different affinities to PS molecule were delineated. Being located in different parts of the CT molecule, these anion-binding sites can potentially facilitate and modulate the multi-step process of the toxin insertion into lipid bilayers. This feature together with the diverse binding affinities of the sites to a wide variety of anionic targets on the membrane surface appears to be functionally meaningful and may adjust CT action against different types of cells

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

Study of doubly strange systems using stored antiprotons

Bound nuclear systems with two units of strangeness are still poorly known despite their importance for many strong interaction phenomena. Stored antiprotons beams in the GeV range represent an unparalleled factory for various hyperon-antihyperon pairs. Their outstanding large production probability in antiproton collisions will open the floodgates for a series of new studies of systems which contain two or even more units of strangeness at the P‾ANDA experiment at FAIR. For the first time, high resolution γ-spectroscopy of doubly strange ΛΛ-hypernuclei will be performed, thus complementing measurements of ground state decays of ΛΛ-hypernuclei at J-PARC or possible decays of particle unstable hypernuclei in heavy ion reactions. High resolution spectroscopy of multistrange Ξ−-atoms will be feasible and even the production of Ω−-atoms will be within reach. The latter might open the door to the |S|=3 world in strangeness nuclear physics, by the study of the hadronic Ω−-nucleus interaction. For the first time it will be possible to study the behavior of Ξ‾+ in nuclear systems under well controlled conditions