Can Gravitational Waves Prevent Inflation?

To investigate the cosmic no hair conjecture, we analyze numerically 1-dimensional plane symmetrical inhomogeneities due to gravitational waves in vacuum spacetimes with a positive cosmological constant. Assuming periodic gravitational pulse waves initially, we study the time evolution of those waves and the nature of their collisions. As measures of inhomogeneity on each hypersurface, we use the 3-dimensional Riemann invariant ${\cal I}\equiv {}~^{(3)\!}R_{ijkl}~^{(3)\!}R^{ijkl}$ and the electric and magnetic parts of the Weyl tensor. We find a temporal growth of the curvature in the waves' collision region, but the overall expansion of the universe later overcomes this effect. No singularity appears and the result is a ``no hair" de Sitter spacetime. The waves we study have amplitudes between $0.020\Lambda \leq {\cal I}^{1/2} \leq 125.0\Lambda$ and widths between $0.080l_H \leq l \leq 2.5l_H$, where $l_H=(\Lambda/3)^{-1/2}$, the horizon scale of de Sitter spacetime. This supports the cosmic no hair conjecture.Comment: LaTeX, 11 pages, 3 figures are available on request <To [email protected] (Hisa-aki SHINKAI)>, WU-AP/29/9

How to superize Liouville equation

So far, there are described in the literature two ways to superize the Liouville equation: for a scalar field (for $N\leq 4$) and for a vector-valued field (analogs of the Leznov--Saveliev equations) for N=1. Both superizations are performed with the help of Neveu--Schwarz superalgebra. We consider another version of these superLiouville equations based on the Ramond superalgebra, their explicit solutions are given by Ivanov--Krivonos' scheme. Open problems are offered

Studies of jet quenching using isolated-photon + jet correlations in PbPb and pp collisions at sqrt(s[NN]) = 2.76 TeV

Results from the first study of isolated-photon + jet correlations in relativistic heavy ion collisions are reported. The analysis uses data from PbPb collisions at a centre-of-mass energy of 2.76 TeV per nucleon pair corresponding to an integrated luminosity of 150 inverse microbarns recorded by the CMS experiment at the LHC. For events containing an isolated photon with transverse momentum pt(gamma) > 60 GeV and an associated jet with pt(Jet) > 30 GeV, the photon + jet pt imbalance is studied as a function of collision centrality and compared to pp data and PYTHIA calculations at the same collision energy. Using the pt(gamma) of the isolated photon as an estimate of the momentum of the associated parton at production, this measurement allows an unbiased characterisation of the in-medium parton energy loss. For more central PbPb collisions, a significant decrease in the ratio pt(Jet)/pt(gamma) relative to that in the PYTHIA reference is observed. Furthermore, significantly more pt(gamma) > 60 GeV photons in PbPb are observed not to have an associated pt(Jet) > 30 GeV jet, compared to the reference. However, no significant broadening of the photon + jet azimuthal correlation is observed.Comment: Submitted to Physics Letters

The method of removing the cortical layers of the vitreous during vitrectomy

ABSTRACT Purpose. To develop a new method of vitreous cortical layers removal during vitrectomy and to evaluate its effectiveness. Material end methods The study included patients with subtotal or total retinal detachment with the peripheral located breaks. After anterior and middle layers vitrectomy by the standard technique, Kenalog was injected to visualize residual vitreous body then central parts of the retina were smoothened injecting perfluorocarbon liquid (PFCL) in an amount of 1-1.5 ml. и С After that, remote periphery of the vitreous was removed with application of a scleral compression. Cortical layers were separated, from the periphery to the center using alternation of aspiration and cutting modes reaching the PFCL level. Then, PFCL was completely aspirated, and the center of the cortical layers was removed. After removal of the cortical layers the PFCL reinjection tamponed the vitreous cavity. In order to maximize the complete evacuation of subretinal fluid a pinhole retinotomy at ora serrata was previously made. Results. The study included 18 eyes of 18 patients aged from 13 to 73 years. There were no complications during surgical treatment. Intraoperatively the retina was attached in all cases. Silicone oil removal was performed 2-3 months postoperatively. The follow-up after silicone removal ranged from 3 to 12 months. In 2 patients there was a recurrent retinal detachment in long-term postoperative period. Conclusion. The selection of this method in microinvasive vitreoretinal interventions allows to maximize the cortical vitreous layer removal and to reduce the rate of retinal detachment recurrence

Distinctive features of the microsurgical technique of the silicone oil tamponade in aphakic eyes

ABSTRACT Purpose. To optimize the surgical technique of the silicone oil (SO) tamponade in aphakic eyes with the retinal detachment (RD). Material and methods. The RD surgery treatment was performed in 49 eyes of 46 patients. All the patients have undergone pars plana vitrectomy with the silicone oil tamponade. During the operations 20G and 25G instruments were used. All the eyes were aphakic. The technological features of the operation were: the silicone oil injection by the single-step replacing method of perfluorocarbon liquid for silicone oil, the replacement of substances only on a sealed anterior chamber, the light silicone injection after the pre-contraction of the pupil, the peripheral iridectomy, the injection of the saline solution into the anterior chamber in order to prevent the SO migration during the mydriasis, the injection of the miotic solution into the anterior chamber in case of SO migration. Results. The silicone oil tamponade was performed successfully in all aphakic eyes. Silicone oil migrated into the anterior chamber intra-operatively in one case (2%) and during the first day after operation in 2 cases (4.1%). In both cases silicone oil was removed from the anterior chamber by injecting the solution of miotic agent. A prominence of the silicone oil surface into the anterior chamber in the pupil area of various intensity degrees took place in 14 cases (28.6%) intra-operatively and in 3 cases (6.1%) in the early postoperative follow-up. Conclusions. The application of the above described technique of operation allows to prevent in proper time the migration of silicone into the anterior chamber of an eye at different stages of treatment, which makes the operation pars plana vitrectomy with silicone oil tamponade an effective and safe method of RD treatment in aphakic eyes

Possible reasons of idiopathic macular holes

The paper discusses possible reasons leading to development of idiopathic macular holes and suggests that an idiopathic macular hole represents a manifestation of a systemic pathological process resulting in vitreoretinal changes which, in turn, are the direct cause of a macular hole

Результаты изотопных исследований 2013-2016 гг. на закарстованных территориях Сочинского спелеологического района (Западный Кавказ)

Regular testing of karst waters, as well as monitoring of the isotope composition of precipitations, river and groundwater was carried out near the Vorontsovskaya Cave system (Sochi, the Western Caucasus) in 2013-2016. In the Krasnaya Polyana settlement (altitude 650 m asl) the isotope composition of precipitation is approximated by the equation δ2H = 6.82×δ18O + 2.9 (R2 = 0.93; n = 51). In the cold season (average daily air temperature is below +5 °C) composition of the precipitation is δ18O = -10.8‰ and δ2H = -74‰, in warm season - δ18O = -4.4‰ and δ2H = -25‰, and the average annual is δ18O = -7.4‰ and δ2H = -48‰. In the Kudepsta River (near the mouth, altitude 3 m asl) the average isotopic composition of water is δ18O = -10.1‰ and δ2H = -64‰, which is close to precipitations of the cold season, with some extremums during the rain flood. In the Melnichny Creek (the Krasnaya Polyana settlement) there are no the significant seasonal variations in the isotopic composition of water (on average, δ18O = -11.9‰ and δ2H = -78‰). The effect of evaporation on the isotopic composition of water in the stream was observed in the warm period of year. Spring in the Krasnaya Polyana settlement has isotope composition δ18O = -11.3‰ and δ2H = -75‰ on average, which is like to the Melnichny Creek. On the Lower Imeretian lowland (elevation 0-50 m asl) groundwater is recharged during the snow-melt flood due to the infiltration of water from the Mzymta River. Here the isotopic composition of groundwater is δ18O = -10.8‰ and δ2H = -73‰ on average. The Vorontsovskaya Cave system in the cold season is recharged by local precipitations (karst water has composition δ18O = -10.4‰ and δ2H = -69‰), and in warm season - by flow from the remote area (δ18O = -8.0‰ and δ2H = -52‰), which should be located at altitudes of about 1000 m.В районе Воронцовской системы пещер (Сочи, Западный Кавказ) в 2013-2016 гг. выполнено регулярное опробование карстовых вод, а также мониторинг изотопного состава осадков, речных и подземных вод. В Красной Поляне (высота 650 м над ур. моря) изотопный состав атмосферных осадков аппроксимируется уравнением δ2H = 6,82×δ18O + 2,9 (R2 = 0,93; n = 51). Состав осадков холодного сезона (среднесуточная температура воздуха ниже 5 °С) составляет δ18O = -10,8‰ и δ2H = -74‰, тёплого сезона - δ18O = -4,4‰ и δ2H = -25‰, при среднегодовом составе δ18O = -7,4‰ и δ2H = -48‰. В р. Кудепсте вблизи устья (высота 3 м над ур. моря) средний изотопный состав воды δ18O = -10,1‰ и δ2H = -64‰, в её стоке преобладают осадки холодного периода года с дождевыми паводками. В Мельничном ручье (Красная Поляна) значительных сезонных колебаний изотопного состава не обнаружено (в среднем, δ18O = -11,9‰ и δ2H = -78‰). В тёплый период года отмечается влияние испарения на изотопный состав воды в ручье. Источник (Красная Поляна) имеет в среднем δ18O = -11,3‰ и δ2H = -75‰. На Нижнеимеретинской низменности (высота 0-50 над ур. моря) подземные воды восполняют запасы в период снеготалого половодья в результате инфильтрации воды из р. Мзымта, их изотопный состав, в среднем, δ18O = -10,8‰ и δ2H = -73‰. Воронцовская система пещер в холодный сезон питается за счёт местных осадков (δ18O = -10,4‰ и δ2H = -69‰), а в тёплый - за счёт удалённой области питания (δ18O = -8,0‰ и δ2H = -52‰), находящейся на высотах около 1000 м

Evaluation of safety of binary tamponade of vitreous cavity in surgical treatment of retinal detachment

ABSTRACT Purpose. To assess the safety of retinal detachment surgery employing double endotamponade with PFCL and silicone oil for 30 days. Material and methods. Inclusion criteria: retinal detachment with retinal breaks located in both upper and lower retina and/or with residual severe proliferative vitreoretinopathy. In the study group (26 eyes) the surgery was finished with double tamponade with PFCL and silicone oil. In the control group (20 eyes) the surgery was finished with silicone oil tamponade. Tamponade agents were removed 1 month later. Examinations included optical coherence tomography (OCT) and microperimetry along with standard eye examination. Results. Retinal reattachment by means of one surgical procedure was achieved in 81% in the study group and in 65% in the control group. There was no significant difference in BCVA between the two groups. OCT data analysis showed no significant differences between the groups in the thickness of outer and inner nuclear layers. Microperimetry detected no significant differences in light sensitivity between the groups. Conclusion. Double endotamponade with PFCL and silicone oil seems to be a safe method for the treatment of complicated retinal detachments