91 research outputs found
Infrared Spectroscopy of Parent Volatiles in Comets: Chemical Diversity and a New Fluorescence Model for the Ethane nu5 Band
This work investigates the chemical and dynamical diversities of comets, and explores the clues they hold to understanding the formation and evolution of the Solar System. This research is based on analysis of high-resolution infrared spectroscopic data obtained with the Near Infrared Echelle Spectrograph on the Keck II telescope. Gas production rates of parent volatile species released from cometary nuclei are measured, and the relative enrichment of organics in comets, with respect to the dominant volatile - H2O - is determined. These measurements require fluorescence models for each species, as well as derivation of an accurate rotational temperature.
A major contribution of this work is the development of a theoretical model of the fluorescence of the infrared C2H6 nu5 band in comets (at 2896 cm-1), which can be used to derive an accurate rotational temperature for this parent volatile (unlike the C2H6 nu7 band at 2985 cm-1). As a symmetric hydrocarbon C2H6 is uniquely observed in the infrared, and now brings the number of molecules for which we can derive a rotational temperature to four (along with H2O, HCN and CO). Also, C2H6 nu5 is observed simultaneously with H2CO, OH, CH4, HCN, C2H2 and H2O, which eliminates many systematic effects.
The C2H6 nu5 model is applied to cometary spectra, and it used to extract ethane rotational temperatures, production rates and mixing ratios. The rotational temperatures derived from C2H6 nu5 agree with those measured for H2O (and other species). Mixing ratios from the C2H6 nu7 band are also confirmed by the nu5 band - agreement is within 1-sigma (2-sigma in one case).
Analysis of the depleted organic composition of the Oort cloud comet C/2000 WM1 (LINEAR) is presented, along with the ecliptic comet 2P/Encke, and their compositions are compared with those of other comets. The results from this dissertation contribute to understanding physics in the inner cometary coma, and on a grander scale - to the exploration of cometary origins in terms of Solar System formation and evolution
THE IMPACT OF PANDEMIC ISOLATION ON THE PROCESS OF EDUCATION
This work discusses the problems of modern education due to the social and economic impact of COVID-19 on society, and it is an attempt to describe the new reality for many educators, along with prescriptions for mitigating the overall burden on the education process by imposing specific national and European policies. The theoretical narrative aims at informing the researchers in the area of education, as well as teachers, educators and to expand the horizons of many students, explicitly majoring in early education and pedagogy on important current topics of modern culture.This work discusses the problems of modern education due to the social and economic impact of COVID-19 on society, and it is an attempt to describe the new reality for many educators, along with prescriptions for mitigating the overall burden on the education process by imposing specific national and European policies. The theoretical narrative aims at informing the researchers in the area of education, as well as teachers, educators and to expand the horizons of many students, explicitly majoring in early education and pedagogy on important current topics of modern culture
Preventive Health Care and Disease Prevention
In the last decades it was evident that the health problems worldwide could not be solved only by spending money for disease treatment but by creating and application of disease prevention strategies. The aim of this paper is to give a common understanding about the major tasks of the prevention medicine, about the types and activities of the prevention. It describes the differences between disease prevention and health promotion. The levels of the diseases prevention are presented. The strategies of preventive medicine, their advantages, disadvantages and interaction are explained. The paper gives information how the evaluation of possibilities for diseases prevention could be done. At the end, the reader will learn about the necessary premises for a successful preventive startegy in the policy of preventive medicine
Influence of Intragroup Dynamics and Intergroup Relations on Authenticity in Organizational and Social Contexts: A Review of Conceptual Framework and Research Evidence
Despite their shared focus on influence of groups on individual, research bridging intragroup dynamics and intergroup relations as predictors of authentic and inauthentic (self-alienated) experience, behavior and interaction of individuals in organizational and social contexts is surprisingly rare. The goal of the present article is to highlight how understanding the reciprocal dynamic relationship between intragroup processes and intergroup relations offers valuable new insights into both topics and suggests new, productive avenues for psychological theory, research and practice development – particularly for understanding and improving the intragroup and intergroup relations in groups, organizations and society affecting authentic psychosocial functioning. The article discusses the complementary role of intergroup and intragroup dynamics, reviewing how intergroup relations can affect intragroup dynamics which, in turn, affects the authenticity of individual experiences, behaviors and relations with others. The paper considers the implications, theoretical and practical, of the proposed reciprocal relationships between intragroup and intergroup processes as factors influencing authentic psychosocial functioning of individuals in organizational and social settings
Social impacts of mining : a Western Australian community case study
Social impacts of mining is not a new area of study. The intensive resource extraction over the last ten years, together with the societal challenges occurring at a global scale, and the progress of the sustainability agenda, are changing the way mining impacts on local communities. Understanding the social implications of mining operations at the local community level appears to be a challenging research exercise that resembles a complex puzzle.The study presented in this thesis seeks to explore the complexities and drivers generating social impacts of mining at a local community level and how this relates to community’s long-term development. The concept of social sustainability is the primarily focus used to examine and interpret the consequences from contemporary mining operations. Studying the rural community of Boddington in south-west Australia, the research links the concepts of social impacts and social sustainability. It reflects on the qualitative changes occurring in the social landscape and analyses the role of mining for long-term community development by examining its contribution against the social implications it evokes.The findings of this inquiry demonstrate the complex nature of the social impacts caused by mining operations. It identifies three new phenomena impacting the social sustainability prospects of the community, namely the appropriation of human resources, transiency and dependency culture. The case study unveils the inextricable links between the drivers that generate impacts and brings forward the importance of analysing and exploring the dynamic interactions between the various social indicators in order to understand how mining affects local communities
Preventive Health Care and Disease Prevention
In the last decades it was evident that the health problems worldwide could not be solved only by spending money for disease treatment but by creating and application of disease prevention strategies. The aim of this paper is to give a common understanding about the major tasks of the prevention medicine, about the types and activities of the prevention. It describes the differences between disease prevention and health promotion. The levels of the diseases prevention are presented. The strategies of preventive medicine, their advantages, disadvantages and interaction are explained. The paper gives information how the evaluation of possibilities for diseases prevention could be done. At the end, the reader will learn about the necessary premises for a successful preventive startegy in the policy of preventive medicine
Regulation of the Duration of Spawning Cycles of Catfish in Industrial Aquaculture
This article is devoted to the study of the qualitative and quantitative characteristics of the African Catfish Clarias gariepinus eggs produced at different durations of the inter-spawning interval. Eggs were produced artificially using sex hormones. In industrial aquaculture, the African Catfish Clarias gariepinus does not reproduce naturally. Therefore, the problem of obtaining high-quality eggs that will be used for in-vitro fertilization is urgent. To implement artificial spawning of fish in industrial aquaculture, it is necessary to correctly choose the effective hormonal stimulator and empirically select its dose. Sex hormones are involved in regulating the duration of the inter-spawning interval and affect the quality of eggs produced both for fertilization and for food purposes. The pituitary gland of the African Catfish Clarias gariepinus and surfagon were used as gametogenesis stimulators. The aim of the work was to study the optimal duration of the inter-spawning interval and the effect of hormonal inducers used to stimulate artificial spawning in industrial aquaculture. The use of the catfish pituitary gland in fresh or acetonated form as a hormonal stimulator provided higher-quality eggs, compared to the synthetic hormonal drug - surfagon. Stimulation with acetonated pituitary injections reduced the inter-spawning interval of the African Catfish Clarias gariepinus to three months, and the use of surfagon prolonged the inter-spawning interval to four months. Reducing the duration of the inter-spawning interval is important for the production of the African Catfish Clarias gariepinus eggs for food purposes. Studies have shown that reducing the optimal duration of the inter-spawning interval negatively affects the quality of the produced eggs and their quantity. This research was financially supported by a grant from the Russian Foundation for Fundamental Research, project No. 18-016-00127.
Keywords: aquaculture, African Catfish Clarias gariepinus, eggs, inter-spawning period, sex hormones, oocyte
Thracian golden wreath from Kabyle, Bulgaria: chemical composition
The chemical composition of a Thracian gold wreath from Kabyle dated to 4th century BC (Thracian age in Bulgaria) was analyzed. Au, Ag and Cu concentrations were determined by inductively coupled plasma-atomic emission spectrometry (ICP-AES) while As, Bi, Cd, Co, Fe, Zn, Sn, Sb, Ga, In, Mn, Mo, Ni, Pb, PGEs (Pt, Pd, Ir, Re, Rh, Ru), Se, Te, Ti, U, W, Zn, and Zr concentrations – by inductively coupled plasma-mass spectrometry (ICP-MS). Data showed that the wreath was made of very well purified gold alloy (Au content between 97.1 and 99.9%). The bivariate plot of the Pd and Pt concentrations showed that the gold used for these artefacts came from four different sources. Due to the lack of analytical data about the platinum group elemental (PGEs) concentrations from different gold sources in Bulgaria it was impossible at this stage to identify the geographical location of the four sources for the gold wreath.La composition chimique de la couronne d’or thrace provenant de Kabyle, daté du IVe siècle av. J.-C. (second Âge du Fer) a été déterminée. Les concentrations en Au, Ag et Cu a été établit par spectrométrie d'émission atomique couplée à une torche plasma (ICP-AES) et les teneurs en As, Bi, Cd,CO, Fe, Zn, Sn, Sb, Ga, In, Mn, Mo, Ni, Pb, PGEs (Pt, Pd, Ir, Re, Rh, Ru), Se, Te, Ti, U, W, Zn et Zr par spectrométrie de masse couplée à un plasma inductif (ICP-MS). Les données ont montré que la couronne a été réalisée avec un alliage d'or assez pure (Au entre 97.1 et 99.9%). Le rapport entre les concentrations en Pd et en Pt a montré que l’or utilisé pour la fabrication de cet objet provient de quatre sources différentes. À cause du manque de données analitiques disponibles sur les concentration en PGEs dans les différents sources d'or de Bulgarie, il a été impossible à ce stade d'identifier leur location géographique
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