974 resultados para Influence of environment
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The influence of environment on social entrepreneurship requires more concerted examination. This paper contributes to emerging discussions in this area through consideration of social entrepreneurship in South Africa. Drawing upon qualitative case study research with six social enterprises, and examined through a framework of new institutional theories and writing on new venture creation, this research explores the significance of environment for the process of social entrepreneurship, for social enterprises, and for social entrepreneurs. Our findings provide insights on institutional environments, social entrepreneurship, and the interplay between them in the South African context, with implications for wider social entrepreneurship scholarship.
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This article reports on a series of experiments with polyethylene terepthalate (PET) treated in a radio frequency plasma reactor using argon and oxygen as a gas fuel, for treatment times equal to 5 s, 20 s, 30 s, and 100 s. The mechanical strength modification of PET fibers, evaluated by tensile tests on monofilaments, showed that oxygen and argon plasma treatment resulted in a decrease in the average tensile strength compared with the untreated fibers. This reduction in tensile strength is more significant for argon plasma and is very sensitive to the treatment time for oxygen plasma. Scanning electron microscopy (SEM) used to analyze the effects of cold plasma treatment on fiber surfaces indicates differences in roughness profiles depending on the type of treatments, which were associated with variations in mechanical strength. Differences in the roughness profile, surveyed through an image analysis method, provided the distance of roughness interval, D-ri. This parameter represents the number of peaks contained in a unit length and was introduced to correlate fiber surface condition, before and after cold plasma treatments, and average tensile strength. Statistical analysis of experimental data, using Weibull cumulative distribution and linear representation, was performed to explain influences of treatment time and environmental effects on mechanical properties. The shape parameter, alpha, and density parameter, beta, from the Weibull distribution function were used to indicate the experimental data range and to confirm the mechanical performance obtained experimentally.
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"From the Smithsonian report for 1895."
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This is an Ecology term paper.
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This chapter considers various aspects of the influence of the environment on the growth of foliose lichens and its significance in determining the ecology of individual species. Radial growth (RaG) and growth in mass of foliose lichens is influenced by climate and microclimate and also by substratum factors such as rock and bark texture, substrate chemistry, and nutrient enrichment. Seasonal fluctuations in growth, as measured by radial growth rate (RaGR) per month, often correlate best with average or total rainfall, the number of rain days, or rainfall in a specific season. Temperature has also been identified to be an important climatic factor influencing growth in some studies. Interactions between microclimatic factors and especially light intensity, temperature, and moisture status are important in determining differences in growth in relation to aspect and slope of the substratum. The physical and chemical nature of the substratum has a profound influence on the growth of foliose lichens. Hence, the effects of texture, porosity, rate of drying, and the physical changes of the substratum on growth are likely to influence lichen distributions. Bird droppings may influence growth and survival by smothering the thalli, altering the pH, or adding inhibitory and stimulatory compounds. Nitrogen and phosphate availability may also influence growth. Chemical factors also have an important influence on lichens of maritime rocks, the effect of salinity and calcium ions being of particular importance. Effects of environmental factors on growth influence the competitive ability of a lichen and ultimately its ecology and distribution.
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Radial growth and growth in mass of lichens is influenced by climatic and microclimatic factors and also by substratum factors such as rock and bark texture, chemistry, and nutrient enrichment. Seasonal fluctuations in growth, as measured by radial growth rate (RaGR) per month, often correlate best with average or total rainfall, the number of rain days, or rainfall in a specific season. Temperature is also considered to be an important climatic factor in some studies. Interactions between microclimatic factors and especially light intensity, temperature, and moisture are the most important in determining local annual growth rates. The physical and chemical nature of the substratum has a profound influence on the growth of foliose lichens. Hence, the effects of texture, porosity, rate of drying, and the physical changes of the substratum on growth are likely to influence lichen distributions. Bird droppings may influence growth and survival by smothering the thalli, altering the pH, or adding inhibitory and stimulatory compounds. Nitrogen and phosphate availability may also influence growth. Chemical factors may also have an important influence on lichens of maritime rocks, the effect of salinity and calcium ions being of particular importance. Zinc, copper, and mercury may also be important in lichen growth as they have been shown to affect the chlorophyll content of lichen algae. Effects of environmental factors on growth influence the competitive ability of lichens thus influencing their ecology and distribution.
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This work focuses on the analysis of the influence of environment on the relative biological effectiveness (RBE) of carbon ions on molecular level. Due to the high relevance of RBE for medical applications, such as tumor therapy, and radiation protection in space, DNA damages have been investigated in order to understand the biological efficiency of heavy ion radiation. The contribution of this study to the radiobiology research consists in the analysis of plasmid DNA damages induced by carbon ion radiation in biochemical buffer environments, as well as in the calculation of the RBE of carbon ions on DNA level by mean of scanning force microscopy (SFM). In order to study the DNA damages, besides the common electrophoresis method, a new approach has been developed by using SFM. The latter method allows direct visualisation and measurement of individual DNA fragments with an accuracy of several nanometres. In addition, comparison of the results obtained by SFM and agarose gel electrophoresis methods has been performed in the present study. Sparsely ionising radiation, such as X-rays, and densely ionising radiation, such as carbon ions, have been used to irradiate plasmid DNA in trishydroxymethylaminomethane (Tris buffer) and 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES buffer) environments. These buffer environments exhibit different scavenging capacities for hydroxyl radical (HO0), which is produced by ionisation of water and plays the major role in the indirect DNA damage processes. Fragment distributions have been measured by SFM over a large length range, and as expected, a significantly higher degree of DNA damages was observed for increasing dose. Also a higher amount of double-strand breaks (DSBs) was observed after irradiation with carbon ions compared to X-ray irradiation. The results obtained from SFM measurements show that both types of radiation induce multiple fragmentation of the plasmid DNA in the dose range from D = 250 Gy to D = 1500 Gy. Using Tris environments at two different concentrations, a decrease of the relative biological effectiveness with the rise of Tris concentration was observed. This demonstrates the radioprotective behavior of the Tris buffer solution. In contrast, a lower scavenging capacity for all other free radicals and ions, produced by the ionisation of water, was registered in the case of HEPES buffer compared to Tris solution. This is reflected in the higher RBE values deduced from SFM and gel electrophoresis measurements after irradiation of the plasmid DNA in 20 mM HEPES environment compared to 92 mM Tris solution. These results show that HEPES and Tris environments play a major role on preventing the indirect DNA damages induced by ionising radiation and on the relative biological effectiveness of heavy ion radiation. In general, the RBE calculated from the SFM measurements presents higher values compared to gel electrophoresis data, for plasmids irradiated in all environments. Using a large set of data, obtained from the SFM measurements, it was possible to calculate the survive rate over a larger range, from 88% to 98%, while for gel electrophoresis measurements the survive rates have been calculated only for values between 96% and 99%. While the gel electrophoresis measurements provide information only about the percentage of plasmids DNA that suffered a single DSB, SFM can count the small plasmid fragments produced by multiple DSBs induced in a single plasmid. Consequently, SFM generates more detailed information regarding the amount of the induced DSBs compared to gel electrophoresis, and therefore, RBE can be calculated with more accuracy. Thus, SFM has been proven to be a more precise method to characterize on molecular level the DNA damage induced by ionizing radiations.
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Most epidemiological studies concerning differentiated thyroid cancers (DTC) indicate an increasing incidence over the last two decades. This increase might be partially explained by the better access to health services worldwide, but clinicopathological analyses do not fully support this hypothesis, indicating that there are carcinogenetic factors behind this noticeable increasing incidence. Although we have undoubtedly understood the biology and molecular pathways underlying thyroid carcinogenesis in a better way, we have made very little progresses in identifying a risk profile for DTC, and our knowledge of risk factors is very similar to what we knew 30-40 years ago. In addition to ionizing radiation exposure, the most documented and established risk factor for DTC, we also investigated the role of other factors, including eating habits, tobacco smoking, living in a volcanic area, xenobiotics, and viruses, which could be involved in thyroid carcinogenesis, thus, contributing to the increase in DTC incidence rates observed.
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A person’s physical and social environment is considered as an influencing factor in terms of rates of engagement in physical activity. This study analyses the influence of socio-demographic, physical and social environmental factors on physical activity reported in the adult population in Andalusia. This is a cross-sectional study using data collected in the Andalusia Health Survey in 1999 and 2003. In addition to the influence of the individual’s characteristics, if there are no green spaces in the neighbourhood it is less likely that men and women will take exercise (OR = 1.26; 95% CI = 1.13, 1.41). Likewise, a higher local illiteracy rate also has a negative influence on exercise habits in men (OR = 1.39; 95% CI = 1.21, 1.59) and in women (OR = 1.22; 95% CI = 1.07, 1.40). Physical activity is influenced by individuals’ characteristics as well as by their social and physical environment, the most disadvantaged groups are less likely to engage in physical activity
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A person's physical and social environment is considered as an influencing factor in terms of rates of engagement in physical activity. This study analyses the influence of socio-demographic, physical and social environmental factors on physical activity reported in the adult population in Andalusia. This is a cross-sectional study using data collected in the Andalusia Health Survey in 1999 and 2003. In addition to the influence of the individual's characteristics, if there are no green spaces in the neighbourhood it is less likely that men and women will take exercise (OR = 1.26; 95% CI = 1.13, 1.41). Likewise, a higher local illiteracy rate also has a negative influence on exercise habits in men (OR = 1.39; 95% CI = 1.21, 1.59) and in women (OR = 1.22; 95% CI = 1.07, 1.40). Physical activity is influenced by individuals' characteristics as well as by their social and physical environment, the most disadvantaged groups are less likely to engage in physical activity.
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This thesis examines the interplay between state regulation and the way organisations define performance. Performance is generally understood to be a multidimensional concept, but the extent to which its different facets are shaped by regulation remains an understudied question. This thesis aims to address this question and provide at least a partial answer to it. To do so, it examines whether the level of regulation amplifies or abates the multidimensionality of regulated entities' performance definition, i.e. the way they define the concept of performance. The leading question is whether an organisation's performance definition can be associated with the regulatory intensity its environment confronts it with. Moreover, the study explores whether the type of ownership-public or private-plays a role in regard to how a regulated entity defines performance. In order to undertake this investigation, the thesis focuses on the performance definitions of organisations in six different sport betting and lottery regulations. Qualitative data is gathered from primary and secondary documents as well as through semi-structured interviews with chief executive officers (CEO), members of executive management and gambling experts in each of these countries. The thesis concludes that the performance definitions of the organisations under study are indeed multidimensional, as well as clearly influenced by their respective regulatory environments. However, not all performance dimensions identified in the literature are present, nor can they all be estimated to be part of the performance definition. In addition, the public-private difference in defining performance-as conceptualised in the literature- seems to be abated in a regulated environment. The central role played by regulation in regard to the multidimensionality of the performance definition partially outweighs the effect of the nature of ownership.
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At the time of moving towards knowledge-based economy, countries pay much attention to innovations by making them a central issue in countries’ innovation policy development. Innovations are influenced much by the institutional environment, in which they are created. That is why exploration of National Innovation Systems, as an important part of such an environment, became central in works of different researchers all over the world.