Area Decay Law Implementation for Quark String Fragmentation

We apply the Area Decay Law (ADL) straightforwardly to simulate a quark string hadronization and compare the results with the explicit analytic calculations. We show that the usual "inclusive" Monte--Carlo simulations do not correspond to the ADL because of two mistakes: not proper simulation of two--dimensional probability density and lack of an important combinatorial factor in a binary tree simulation. We also show how to simulate area decay law "inclusively" avoiding the above--mentioned mistakes.Comment: 5 pages (REVTEX) + 3 figures (available in ps format from G.G.Leptoukh , IPGAS-HE/93-3, to be published in Phys. Rev.

Second Stage String Fragmentation Model

A string model, advocated by Bowler, provides a physical and intuitive picture of heavy quark fragmentation. When supplemented by an ad hoc factor of (1-z), to suppress fragmentation near z=1, it supplies an excellent fit to the data. We extend Bowler's model by accounting for the further decay of the massive mesonic states produced by the initial string breaking. We find that each subsequent string break and cascade decay beyond the first, introduces a factor of (1-z). Furthermore we find that including a finite mass for the quarks, which pop out of the vacuum and split the string, forces the first string breaking to produce massive states requiring further decay. This sequence terminates at the second stage of fragmentation where only relatively "light" heavy meson systems are formed. Thus we naturally account for the phenomenologically required factor of (1-z). We also predict that the ratio of (primary) fragments-vector/(vector plus scalar) should be .61. Our second stage string fragmentation model provides an appealing picture of heavy quark fragmentation.Comment: 15 page

Semiclassical Decay of Excited String States on Leading Regge Trajectories

We study the decay of hadrons based on a semiclassical string model. By including quark mass effects we find that the width to mass ratio \G/m is an increasing function of $m$, which increases most rapidly for massive quarks. This is consistent with the available data. The decay probability of hadrons on the leading Regge trajectories is computed taking the effect of the string rotation into account. The resulting decay probability is no longer uniform along the length of the string but varies in a manner that is in qualitative agreement with the available data. We argue in favour of possible experiments that would test our predictions more accurately and help open a window to the nonperturbative aspects of QCD.Comment: 15 PAGES, UR-1326, ER-40685-776, SU-4240-55

Generation of small-scale structures in the developed turbulence

The Navier-Stokes equation for incompressible liquid is considered in the limit of infinitely large Reynolds number. It is assumed that the flow instability leads to generation of steady-state large-scale pulsations. The excitation and evolution of the small-scale turbulence is investigated. It is shown that the developed small-scale pulsations are intermittent. The maximal amplitude of the vorticity fluctuations is reached along the vortex filaments. Basing on the obtained solution, the pair correlation function in the limit $r\to 0$ is calculated. It is shown that the function obeys the Kolmogorov law $r^{2/3}$.Comment: 18 page

INFLUENCE EXERTED BY SOMATIC PATHOLOGY ON RISKS OF OCCUPATIONAL LUNG FIBROSIS IN WORKERS EMPLOYED AT REFRACTORY PRODUCTION

Occupational lungs and bronchial pathology occurs not only under exposure to dusts, their aerosol structure and aggression, but also depends on individual properties of a body. The latter can determine either increased body resistance or susceptibility to occupational pathology occurrence. Our research goal was to determine influence exerted by somatic pathology on occupational lung fibrosis occurrence as well as to estimate prevalence of risk factors for cardiovascular and metabolic pathology occurrence in workers employed at refractory production. At the first stage 449 workers employed at refractory production were examined at a periodical medical examination (PME). Patients' average age was 41.59 ± 0.45 and average work experience was 14.47 ± 0.39 years. At the second stage 172 workers were examined at an occupational pathology center; 75 out of them were workers who had silicosis and were included into the test group and the remaining 97 workers didn't have any occupational pathology and were included into the reference group. Both groups were comparable as per sex (p = 0.0052) and work experience under exposure to dusts (p = 0.862). Workers examined at a PME most frequently had overweight and obesity (68 %). Arterial hypertension (AH) prevalence amounted to 19.5%; carbohydrate metabolism disorders, 19.8 %; 48.1 % workers had hypercholesterolemia. Patients with silicosis had certain disorders significantly more frequently than workers with long work experience but without any occupational pathologies; those disorders were AH, cardiac muscle hypertrophy in the left ventricle, ischemic heart disease, heart rate disorders, as well as mixed (obstructive and restrictive) breath mechanics disorders. We determined some factors that authentically produced certain effects on occupational lung fibrosis occurrence in workers employed at refractory production. Median time of silicosis occurrence was significantly shorter (by 11.5 years) among workers with severe AH, arrhythmia (by 13 years), lower hemoglobin in blood (by 11.5 years). Besides, silicosis occurred significantly earlier (by 10.8) among women than among men. © 2020 Obukhova T.Yu., Budkar' L.N., Gurvich V.B., Solodushkin S.I., Shmonina O.G., Karpova E.A.,. All Rights Reserved

New Insights into the mineralogy of the Atlantis II deep metalliferous sediments, Red Sea

The Atlantis II Deep of the Red Sea hosts the largest known hydrothermal ore deposit on the ocean floor and the only modern analog of brine pool-type metal deposition. The deposit consists mainly of chemical-clastic sediments with input from basin-scale hydrothermal and detrital sources. A characteristic feature is the millimeter-scale layering of the sediments, which bears a strong resemblance to banded iron formation (BIF). Quantitative assessment of the mineralogy based on relogging of archived cores, detailed petrography, and sequential leaching experiments shows that Fe-(oxy)hydroxides, hydrothermal carbonates, sulfides, and authigenic clays are the main “ore” minerals. Mn-oxides were mainly deposited when the brine pool was more oxidized than it is today, but detailed logging shows that Fe-deposition and Mn-deposition also alternated at the scale of individual laminae, reflecting short-term fluctuations in the Lower Brine. Previous studies underestimated the importance of nonsulfide metal-bearing components, which formed by metal adsorption onto poorly crystalline Si-Fe-OOH particles. During diagenesis, the crystallinity of all phases increased, and the fine layering of the sediment was enhanced. Within a few meters of burial (corresponding to a few thousand years of deposition), biogenic (Ca)-carbonate was dissolved, manganosiderite formed, and metals originally in poorly crystalline phases or in pore water were incorporated into diagenetic sulfides, clays, and Fe-oxides. Permeable layers with abundant radiolarian tests were the focus for late-stage hydrothermal alteration and replacement, including deposition of amorphous silica and enrichment in elements such as Ba and Au

Cardiovascular and Metabolic Disorders Associated with Occupational Lung Fibrosis in Employees Exposed to the Dust at the Workplace

Introduction. The attribution of certain medical conditions in industrial workers to hazardous exposures at the workplace remains a challenging issue of occupational health. Material and methods. In order to identify cardiovascular conditions associated with occupational lung diseases in workers exposed to fibrogenic dust, we conducted a medical check-up examination of individuals employed in refractory production and asbestos industry. The main group consisted of the patients with a confirmed diagnosis of lung fibrosis (asbestosis, silicosis); the reference group was age- and tenure-matched workers without occupational fibrosis. Results. We e stablished a significantly h igher prevalence of arterial hypertension, left ventricular hypertrophy, s inus tachycardia, obesity, hypertriglyceridemia and impaired fasting glycemia in workers with silicosis and asbestosis if compared to those without work-related diseases. Based on the relative risk and attributable fraction estimates, we assume there is moderate occupational causation for arterial hypertension and a strong one for left ventricular hypertrophy, sinus tachycardia, and obesity. Very strong causation was found between occupational exposure to fibrogenic dust and carbohydrate metabolism disorders. High-stage hypertension, dyslipidemia and left ventricular hypertrophy were found to have a statistically significant impact on the timing of silicosis. Whereas high-stage hypertension, coronary artery disease, left ventricular hypertrophy and obesity were found to impact the timing of asbestosis. Conclusion. Cardiovascular and metabolic disorders are statistically more occurrent in workers with silicosis or asbestosis. Therefore, the disease can be regarded as work-related. We established cardiovascular and metabolic disorders to have a statistically significant impact on the timing of silicosis and asbestosis. Therefore, a timely CVD prophylaxis could reduce the risk of occupational lung fibrosis in workers exposed to fibrogenic dust. © 2020 Izdatel'stvo Meditsina. All rights reserved.The work of Solodushkin was supported by Act 211 Government of the Russian Federation, contract No 02.A03.21.0006

Prediction of Occupational Fluorosis in Aluminum Production Workers in View of Comorbidities

Introduction: Modern research on occupational medicine has shown that general diseases contribute the most to health deterioration in workers of hazardous industries and significantly affect the timing of the onset of occupational diseases. Objective: To assess the impact of comorbid disorders on the probability of occupational fluoride toxicity in aluminum production workers. Materials and methods: The paper describes existing international scales used to assess comorbid disorders and emphasizes the relevance of publications on the comorbidity of workers of hazardous and harmful industries. The comorbidity index was calculated for each of 201 aluminum production workers. Comorbidity index calculations, health indicators, and parameters of working conditions were entered in the electronic database. The article presents a method for determining the probability of occupational disease development using a logistic regression. Results: A prognostic model was built using a logistic regression and comorbidity indices to determine the influence of human body systems on the probability of developing occupational fluoride poisoning (fluorosis). Conclusion: Using the logistic regression, we have determined combinations of comorbidity indices having a strongest effect on the probability of fluoride poisoning for prediction and implementation of appropriate preventive measures. To reduce the likelihood of occupational diseases, it is necessary to treat comorbid disorders in workers of harmful industries. © 2023, Federal Center for Hygiene and Epidemiology. All rights reserved