81 research outputs found

    Modeling of the Continuous Absorption of Electromagnetic Radiation in Dense Hydrogen Plasma

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    In this work is examined a new modeling way of describing the continuous absorption of electromagnetic (EM) radiation in a dense partially ionized hydrogen plasmas with electron densities about 510185\cdot10^{18} cm3^{-3} - 1.510191.5\cdot10^{19}cm3^{-3} and temperatures about 1.61041.6 \cdot10^{4} K - 2.51042.5 \cdot 10^{4} K in the wavelength region 300nm<λ<500nm300 \textrm{nm} < \lambda < 500 \textrm{nm}. The obtained results can be applied to the plasmas of the partially ionized layers of different stellar atmospheres

    Contamination, risk, and source apportionment of potentially toxic microelements in river sediments and soil after extreme flooding in the Kolubara River catchment in Western Serbia

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    Climate change is contributing to an increase in extreme weather events. This results in a higher river flooding risk, causing a series of environmental disturbances, including potential contamination of agricultural soil. In Serbia, the catastrophic floods of 2014 affected six river basins, including the Kolubara River Basin, as one of the larger sub-catchments of the large regional Sava River Basin, which is characterized by large areas under agricultural cultures, various geological substrates, and different types of industrial pollution. The main aim of this study was to establish the sources of potentially toxic elements in soil and flood sediments and the effect of the flood on their concentrations. Field sampling was performed immediately after water had receded from the flooded area in May 2014. In total, 36 soil samples and 28 flood sediment samples were collected. After acid digestion (HNO3), concentrations of the most frequent potentially toxic elements (PTE) in agricultural production (As, Cd, Cr, Cu, Ni, Pb, Zn) and Co which are closely related to the geological characteristics of river catchments, were analyzed. The origin, source, and interrelations of microelements, as well as BACKGROUND: values of the PTE of the river catchment, the pollution index (Pi), enrichment factor (Ef), and geological index (Igeo), were determined, using statistical methods such as Pearson correlations, principal component analysis (PCA), and multiple linear regression (MLRA). The content of the hot acid-extractable forms of the elements, PCA, and MLRA revealed a heavy geological influence on microelement content, especially on Ni, Cr, and Co, while an anthropogenic influence was observed for Cu, Zn, and Cd content. This mixed impact was primarily related to mines and their impact on As and Pb content. The pseudo-total concentrations of all the analyzed elements did not prove to be a danger in the catchment area, except for Cu in some samples, indicating point-source pollution, and Ni, whose pseudo-total content could be a limiting factor in agricultural production. For the Ef, the Ni content in 59% soil and 68% flood sediment samples is classified into influence classes. The similar pseudo-total contents of the elements studied in soil samples and flood sediment and their origin indicate that the long-term soil formation process is subject to periodic flooding in the Kolubara River Basin without any significant changes taking place. This implies that floods are not an endangering factor in terms of the contamination of soil by potentially toxic elements in the explored area

    Predictors of enhancing human physical attractiveness: Data from 93 countries

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    People across the world and throughout history have gone to great lengths to enhance their physical appearance. Evolutionary psychologists and ethologists have largely attempted to explain this phenomenon via mating preferences and strategies. Here, we test one of the most popular evolutionary hypotheses for beauty-enhancing behaviors, drawn from mating market and parasite stress perspectives, in a large cross-cultural sample. We also test hypotheses drawn from other influential and non-mutually exclusive theoretical frameworks, from biosocial role theory to a cultural media perspective. Survey data from 93,158 human participants across 93 countries provide evidence that behaviors such as applying makeup or using other cosmetics, hair grooming, clothing style, caring for body hygiene, and exercising or following a specific diet for the specific purpose of improving ones physical attractiveness, are universal. Indeed, 99% of participants reported spending &gt;10 min a day performing beauty-enhancing behaviors. The results largely support evolutionary hypotheses: more time was spent enhancing beauty by women (almost 4 h a day, on average) than by men (3.6 h a day), by the youngest participants (and contrary to predictions, also the oldest), by those with a relatively more severe history of infectious diseases, and by participants currently dating compared to those in established relationships. The strongest predictor of attractiveness-enhancing behaviors was social media usage. Other predictors, in order of effect size, included adhering to traditional gender roles, residing in countries with less gender equality, considering oneself as highly attractive or, conversely, highly unattractive, TV watching time, higher socioeconomic status, right-wing political beliefs, a lower level of education, and personal individualistic attitudes. This study provides novel insight into universal beauty-enhancing behaviors by unifying evolutionary theory with several other complementary perspectives

    Current Wildland Fire Patterns and Challenges in Europe: A Synthesis of National Perspectives

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    Changes in climate, land use, and land management impact the occurrence and severity of wildland fires in many parts of the world. This is particularly evident in Europe, where ongoing changes in land use have strongly modified fire patterns over the last decades. Although satellite data by the European Forest Fire Information System provide large-scale wildland fire statistics across European countries, there is still a crucial need to collect and summarize in-depth local analysis and understanding of the wildland fire condition and associated challenges across Europe. This article aims to provide a general overview of the current wildland fire patterns and challenges as perceived by national representatives, supplemented by national fire statistics (2009–2018) across Europe. For each of the 31 countries included, we present a perspective authored by scientists or practitioners from each respective country, representing a wide range of disciplines and cultural backgrounds. The authors were selected from members of the COST Action “Fire and the Earth System: Science & Society” funded by the European Commission with the aim to share knowledge and improve communication about wildland fire. Where relevant, a brief overview of key studies, particular wildland fire challenges a country is facing, and an overview of notable recent fire events are also presented. Key perceived challenges included (1) the lack of consistent and detailed records for wildland fire events, within and across countries, (2) an increase in wildland fires that pose a risk to properties and human life due to high population densities and sprawl into forested regions, and (3) the view that, irrespective of changes in management, climate change is likely to increase the frequency and impact of wildland fires in the coming decades. Addressing challenge (1) will not only be valuable in advancing national and pan-European wildland fire management strategies, but also in evaluating perceptions (2) and (3) against more robust quantitative evidence
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