Opacity of relativistically underdense plasmas for extremely intense laser pulses

It is generally believed that relativistically underdense plasma is transparent for intense laser radiation. However, particle-in-cell simulations reveal abnormal laser field absorption above the intensity threshold about~$3 \times 10^{24}~\mathrm{W}\,\mathrm{cm}^{-2}$ for the wavelength of $1~\mu \mathrm{m}$. Above the threshold, the further increase of the laser intensity doesn't lead to the increase of the propagation distance. The simulations take into account emission of hard photons and subsequent pair photoproduction in the laser field. These effects lead to onset of a self-sustained electromagnetic cascade and to formation of dense electron-positron ($e^+e^-$) plasma right inside the laser field. The plasma absorbs the field efficiently, that ensures the plasma opacity. The role of a weak longitudinal electron-ion electric field in the cascade growth is discussed.Comment: 8 pages, 3 figure

Extreme geomagnetic disturbances due to shocks within CMEs

We report on features of solar wind-magnetosphere coupling elicited by shocks propagating through coronal mass ejections (CMEs) by analyzing the intense geomagnetic storm of 6 August 1998. During this event, the dynamic pressure enhancement at the shock combined with a simultaneous increase in the southward component of the magnetic field resulted in a large earthward retreat of Earth\u27s magnetopause, which remained close to geosynchronous orbit for more than 4 h. This occurred despite the fact that both shock and CME were weak and relatively slow. Another similar example of a weak shock inside a slow CME resulting in an intense geomagnetic storm is the 30 September 2012 event, which strongly depleted the outer radiation belt. We discuss the potential of shocks inside CMEs to cause large geomagnetic effects at Earth, including magnetopause shadowing

Twists in U(sl(3)) and their quantizations

The solution of the Drinfeld equation corresponding to the full set of different carrier subalgebras in sl(3) are explicitly constructed. The obtained Hopf structures are studied. It is demonstrated that the presented twist deformations can be considered as limits of the corresponding quantum analogues (q-twists) defined for the q-quantized algebras.Comment: 31 pages, Latex 2e, to be published in Journ. Phys. A: Math. Ge

PREDICTION BACKUP TESTICULAR FUNCTION IN PATIENTS WITH NONOBSTRUCTIVE AZOOSPERMIA

Modern authors believe that male infertility accounts for 40–50%. The most severe form of male infertility is azoospermia, which is observed in 10–15% of cases. The only method of diagnosis of azoospermia is testicular biopsy, which allows not only to differentiate the secretory and excretory forms of infertility, but also to determine the degree of impairment of spermatogenesis.Purpose. To improve the diagnosis of male infertility.Materials and methods. We have examined 26 men with non-obstructive azoospermia (according to semen). The comparison group included healthy men – 22 people. Patients underwent biopsy of the testicle, followed by morphological analysis of biopsies. Sections of testicular tissue was stained with hematoxylin and eosin, indirect immunohistochemical studies – definition of Inhibin B, a protein prolife ration and apoptosis (ki-67)Results. According to clinical and instrumental examination (ultrasound) we found no abnormalities. Patients set idiopathic form of infertility. When painting testice slices with hematoxylin and eosin, we recorded significant changes in the convoluted seminiferous tubules in patients with azoospermia: the diameter is reduced to 1.5–2 times (hypoplasia), the basement membrane with a strong fiber component (fibrosis) (p < 0,05). Expressed Inhibin tissue expression observed in Sertoli cells (“+++”) and to a lesser extent in spermatogonia ( «±»), located closer to the basal membrane convoluted seminiferous tubule. The expression level of Inhibin in germ cells - up to 5%. ki-67 protein expression was observed in the nuclei (S-phase of mitosis) spermatogonia (“++”) at stages II and III and spermatogenesis in some primary nuclei (“+”) and secondary (“+”) spermatocytes. Expression of ki-67 level in the germ cells – up to 25%.Conclusion. Determination of tissue levels of Inhibin-B can be used as a p rognostic test backup testicular function

Biomarkers of Myopic Choroidal Neovascularization in Women, Determining the Clinical Course and Response to Anti-VEGF Therapy

Aim: to identify clinical and laboratory biomarkers that determine the nature of the course of myopic choroidal neovascularization (mCNV) and the response to anti-VEGF therapy in women.Material and methods. A prospective non-randomized study was conducted in 52 patients (52 eyes) with active mCNV, treated with ranibizumab intravitreally, 0.5mg. After 12months, the suppression of CNV activity, the number of injections and the fellow eye inclusion in the pathological process were taken into account. There were 2 groups: with a favorable clinical course (n = 31, age – 33,0 ± 5,1 years, anterior-posterior axis (APA) 28,5 ± 0,3 mm) and an unfavorable clinical course (n = 21, age – 34,0 ± 4,1 years, APA – 29,01 ± 0,1 mm). Structural retinal changes, choroid thickness, retinal blood flow, and heart rate were evaluated using OCT and OCTA protocols (Optovue XR Avanti, USA). Studies were conducted before the start of therapy and then one time per month. The concentration of sex and pituitary hormones (ELISA analyzer “Immunohem-2100”), lipoprotein A, Apo B/Apo A (Accent 200 Cormay, Poland), coagulogram data (Helena C-2, UK), and the concentration of highly sensitive C-reactive protein in blood serum before the start of antiangiogenic therapy were studied once.Results. In the first group, 1.4 ± 0.7 ranibizumab injections were administered to suppress the CNV activity. In the opposite group – 3.5 ± 2.1 injections, in 73.7 % of cases, relapses were diagnosed, in 3 cases – primary CNV in the fellow eye. Clinical and laboratory biomarkers of the unfavorable clinical course of mCNV were identified: extreme choroidal thinning, highly organized membranes of a large area, dome-shaped deformation of the posterior pole, excess of the reference values of lipoprotein A, fibrinogen and highly sensitive C-reactive protein by two or more times, an imbalance of sex and pituitary hormones (excess of the reference values of prolactin, follicle stimulating hormone, cortisol, progesterone concentration decrease), a predominant change in the menstrual-ovarian cycle according to the type of amenorrhea and opsomenorrhea.Conclusion. Myopic CNV biomarkers in women allow predicting the response to anti-VEGF therapy, the formation of relapses and the inclusion of the fellow eye in the pathological process

Prospects for K+→π+ννˉK^+ \to \pi^+ \nu \bar{ \nu } at CERN in NA62

The NA62 experiment will begin taking data in 2015. Its primary purpose is a 10% measurement of the branching ratio of the ultrarare kaon decay $K^+ \to \pi^+ \nu \bar{ \nu }$, using the decay in flight of kaons in an unseparated beam with momentum 75 GeV/c.The detector and analysis technique are described here.Comment: 8 pages for proceedings of 50 Years of CP