Fragmentation and Multifragmentation of 10.6A GeV Gold Nuclei

We present the results of a study performed on the interactions of 10.6A GeV gold nuclei in nuclear emulsions. In a minimum bias sample of 1311 interac- tions, 5260 helium nuclei and 2622 heavy fragments were observed as Au projec- tile fragments. The experimental data are analyzed with particular emphasis of target separation interactions in emulsions and study of criticalexponents. Multiplicity distributions of the fast-moving projectile fragments are inves- tigated. Charged fragment moments, conditional moments as well as two and three -body asymmetries of the fast moving projectile particles are determined in terms of the total charge remaining bound in the multiply charged projectile fragments. Some differences in the average yields of helium nuclei and heavier fragments are observed, which may be attributed to a target effect. However, two and three-body asymmetries and conditional moments indicate that the breakup mechanism of the projectile seems to be independent of target mass. We looked for evidence of critical point observable in finite nuclei by study the resulting charged fragments distributions. We have obtained the values for the critical exponents gamma, beta and tau and compare our results with those at lower energy experiment (1.0A GeV data). The values suggest that a phase transition like behavior, is observed.Comment: latex, revtex, 28 pages, 12 figures, 3tables, submitted to Europysics Journal

A Proposal of the Photoemulsion Experiment at the National Accelerator Laboratory (Batavia)

The experiments using a cloud chamber in a magnetic field and an ionizing calorimeter exposed io cosmic rays have been performed at the Lebedev Physical Institute I 1-3 I. They have shown that the hadron interactions with a LiH target at the energies of 200-700 Gev can be explained on the basis of the fireball model, supposing one fireball formation in a peripherical process, for about 50 per cent of events. The experiments carried out at the accelerator beams using the photoemulsion method at CERN (Eo = 2l-24 Gev) I 4 I and at Serpukhov (Eo = 60 Gev) I 5 I have indicated that the same model can describe the essential part of the pN- and {pi}iN - interactions (the quasi-free nucleon interactions are selected with the help of the criteria, approbated at the energies of {approx}20 Gev). It seems to be very important to continue this photoemulsion experiment at the energies of 200-500 Gev at the Batavia accelerator retaining the previous method of selecting the quasi-free nucleon interactions and measuring besides the emission angles of the charged particles also the momenta of these particles by their Coulomb scattering. Under the favourable conditions of exposure of the Soviet emulsions one can expect the value of the measurement precision of the particles moments to be {approx} 30% at the particle momenta values p {approx} 30-50 Gev/c. This expected precision, at least, will not be worse than that obtained in the last experiments I 1-3 I, having an advantage of a much better angular resolution, an unambiguous determination of the nature and energy of the primary particles and better statistics. So we hope to realize a new more reliable check of the fireball model application and also any other model concerning the multiple production of particles. The second scientific problem consists of a studying the energetic dependance of the cross-section of the coherent generation of one, three, five and so on charged particles on the photoemulsion nuclei at the proton and {pi}-meson energies of 200-500 Gev and of comparing that with the corresponding data, obtained at the energies of 20-70 Gev. The requirements to the photoemulsion stacks exposure: (a) the protons and pions beams at the energy of 200 Gev and higher, at the maximum accesible one. (b) the total density of the beam within 2-4.10{sup 4} cm{sup -2}; (c) the dip angle to the plane of the, emulsion layer has to be minimum, but advisable not more than 5.10{sup -3}; and (d) on the condition that the beam angle dispersion will not be more than 0.5.10{sup -3} it's desirable to take some control irradiation of the same stacks perpendicular to the emulsion plane to estimate the distortion level. The particles density must be about 10{sup 5} cm{sup -2}. It's advisable to irradiate 2-3 photoemulsion stacks (of a volume of about 1 litre each) with the protons and pions beams at the energy of 200 Gev and higher, at the maximum accesible one. For the control of development quality its necessary to have some possibility to develop a small quantity of the photoemulsion layers during the preparation and exposures at Batavia

Distributions of Rapidity Intervals, Jet Ranges and Maximum Rapidity Gaps in Proton - Proton Interactions at 200-GeV/c

The semiinclusive reaction p+p {yields} n charged particles + anything was investigated with nuclear emulsions irradiated with 200 GeV/c protons at the NAL accelerator (Batavia, US). They measured angles {Theta} of all charged particles. In every event particles were ordered on rapidity which was approximated by the value y = -lntg {Theta}lab/2. In every event particles were numbered on increasing the rapidity. Let us consider, for example, distributions of ordered rapidities and distributions of differences of various ordered rapidities and try to make a physical conclusion from the analysis of these distributions

Фактор фон Виллебранда и миелопероксидаза как лабораторные предикторы выживаемости при тяжелом течении COVID-19

Background. The severe acute respiratory syndrome of the SARS-CoV-2 virus-mediated coronavirus disease 2019 (COVID-19) highlighted the central role of immunothrombosis. Severe endothelial damage with the release of unusually large multimers of von Willebrand factor (vWF) and subsequent consumption of ADAMTS-13 is described during severe COVID-19. The activation of innate immune cells among which neutrophils contribute to the formation of extracellular neutrophil traps (NETs) and to the release of myeloperoxidase (MPO) potentially contributing to the spread of inflammation and microvascular thrombosis. Objective to evaluate the ability of vWF, ADAMTS-13 and MPO to predict in-hospital mortality in severe COVID-19 patients needing mechanical ventilation. Methods. We performed a one-center observational study of 79 severe COVID-19 patients entering intensive care unit for mechanical ventilation, examining vWF, ADAMTS-13 and MPO among other potential predictors for in-hospital death. Results. After multivariate analysis, vWF antigen (vWF:Ag) and MPO antigen (MPO:Ag) were finally the single two parameters which increasing values were independently associated with non-survival; vWF:Ag (U/dL): adjusted OR 3.360, 95% CI 1.5627.228, p = 0.0019; MPO:Ag (ng/ml): adjusted OR 1.062, 95% CI 1.0241.101, p = 0.0011. From these results a simplified mortality score was derived and patients categorized as having a score value higher or lower that the median value of the score: a high score value was associated with a lower cumulative survival rate (p 0.0001), 50% of the cases being dead at day 13 post-hospital admission. Conclusions. In severe COVID-19 necessitating mechanical ventilation, increasing values of MPO activity and of vWF antigen tested at admission are associated with poor survival.Обоснование. Тяжелый острый респираторный синдром, запускаемый вирусом SARS-CoV-2, обозначил центральную роль в патогенезе иммунотромбоза. При тяжелом течении COVID-19 описано массивное повреждение эндотелия с высвобождением большого количества мультимеров фактора фон Виллебранда (vWF) и последующим потреблением ADAMTS-13. Активация клеток врожденного иммунитета, в том числе нейтрофилов, приводит к образованию нейтрофильных внеклеточных ловушек (NETs) и высвобождению миелопероксидазы (МПО), что, в свою очередь, способствует распространению процессов воспаления и тромбоза в микрососудистом русле. Цель оценить прогностическую ценность концентрации vWF, ADAMTS-13 и MПO в отношении внутрибольничной смертности у пациентов с тяжелой формой COVID-19, нуждающихся в искусственной вентиляции легких (ИВЛ). Методы. Проведено одноцентровое наблюдательное исследование с участием 79 пациентов с тяжелым течением COVID-19, находившихся в отделении интенсивной терапии на ИВЛ. У всех пациентов определялись концентрации vWF, ADAMTS-13 и MПO в сыворотке крови, а также другие показатели потенциальные предикторы внутрибольничной смертности. Результаты. Путем проведения многофакторного анализа было показано, что увеличение концентрации таких маркеров, как антиген vWF (vWF:Aг) и MПO человека (MПO:Aг), достоверно и независимо связано с высокой вероятностью смертности; vWF:Aг (ЕД/дл): скорректированное ОШ 3,360; 95%-й ДИ 1,5627,228; р = 0,0019; MПO:Aг (нг/мл): скорректированное ОШ 1,062; 95%-й ДИ 1,0241,101; р = 0,0011. На основании этих результатов был получен упрощенный показатель смертности, и пациенты были классифицированы как имеющие значения данного показателя выше или ниже медианного: высокое значение показателя было связано с более низкой кумулятивной выживаемостью (p 0,0001), в 50% случаев смерть наступала на 13-е сут госпитализации. Выводы. При тяжелом течении COVID-19, требующем ИВЛ, повышенные концентрации МПО и vWF на момент поступления коррелируют с плохой выживаемостью