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991.
Despite the increased importance of and attention to renewable energy, its share in the overall energy mix has varied significantly across countries and over time. There are many determinants of clean energy transitions; this study focuses on political constraints. Here it is argued that political systems that have fewer political constraints have fewer access points through which powerful status quo veto players can slow the progress of clean energy reforms. To test the theory, a hierarchical model is applied on a dataset of 125 countries over four decades. The results provide significant support for the theory. Furthermore, the effects for political constraints hold even when we distinguish between hydro and non-hydro renewable sources and control for regime type. This study builds on research that recognizes the importance of politics in understanding the challenges and opportunities of clean energy reform.  相似文献   
992.
The role of the Siberian musk deer in the diets of the Amur tiger, brown bear, and Asian black bear has been studied in the Sikhote-Alin State Biosphere Reserve in 1992 to 2016. Information has been collected from 763 tiger feeding sites, and the contents of tiger feces have been analyzed. Radiotelemetry has been used to evaluate tiger–musk deer relationships. The musk deer accounted for 0.26% of all animal species found to be eaten by the tiger. Musk deer remains in feces of the tiger, brown bear, and Asian black bear occurred with frequencies of 1.3, 0.2, and 0.3%, respectively. A case of musk deer avoiding the presence of brown bear is described.  相似文献   
993.
Flora of the still unchanged or slightly modified floodplains is particularly valuable. Such are the natural, periodically flooded riparian ecosystems within the Mid-Pripyat river valley in Belarus. Distinctive elements of that area are ‘periodic islands’, which arise from the most elevated parts of the riverbed during flooding and have a specific microtopography. The aim of the research was to recognize floristic composition and ecological conditions of the ‘islands.’ Noted plants were mainly photophilous, by clearly varied in soil moisture, acidity and fertility requirements.  相似文献   
994.
With 21 % of gross domestic product (GDP) in agricultural sector and having consistently experienced natural disasters (e.g., drought, flood), Armenia is very vulnerable to climate and its change. Given the fact that 63 % of the entire land is planted with grains, this study primarily focuses on the market for wheat flour and bread. Economic welfare loss due to drought episodes is calculated using the economic data integrated with climate measures. Economic data are utilized for the period 1995–2011 (obtained from Statistical Office of Armenia) and specifically include the quantity produced and consumed of wheat flour and bread combined with mean prices, population income, GDP in the agricultural sector, GDP in the planting sector, and governmental expenditure on subsidies. Climate data include temperature and precipitation during the period 1966–2011 (obtained from National Hydrometeorological Service of Armenia). The analysis includes three main components. The first utilizes a market framework that analyzes the impact of climate on equilibrium prices and quantities as well as trade and tax effects. The second employs a logarithmic utility function to estimate the effective insurance policy for the agricultural sector using risk management strategies. Lastly, a macroeconomic model has been developed to assess the efficient sum of governmental expenditure on subsidies and irrigation during the drought episodes and during the mean climatic conditions. All three parts of the study are developed for the first time.  相似文献   
995.
Seasonal dynamics of heart rate variability in individuals of late summer and autumn generations have been studied in three rodent species kept in a vivarium: the striped field mouse (Apodemus agrarius), bank vole (Clethrionomys glareolus), and northern red-backed vole (Cl. rutilus). It has been shown that the cardiac function of the rodents in autumn and winter is mainly controlled by autonomic mechanisms: the heart rate is slow, cardiovascular control systems are relaxed. During the winter-spring transition, the role of central cardiovascular circuits increases because of the necessity to activate all body systems by spring.  相似文献   
996.
Data on the ratio of stable carbon isotopes in xylotrophic fungi and their xylic substrates are presented for the first time. It is shown that coniferous substrates are more enriched in the heavy carbon isotope, compared to deciduous substrates. In both cases, however, their carbon isotope composition is characterized by low variability and does not correlate with the species or physiological type of decomposer fungus but shows a statistically significant correlation with the degree of wood mineralization. The ratio of stable carbon isotopes in the fungi depends on that in their substrates but is shifted in favor of the heavier isotope. This trophic shift lacks species specificity, is equally manifested in decomposers of deciduous and coniferous substrates, remains unchanged along the latitudinal climatic gradient, and is positively correlated with the carbon isotope composition of substrates, in the absence of correlation with the degree of their mineralization.  相似文献   
997.
Glaucium flavum Crantz. is a short-lived perennial herb distributed in coastal zones from the Black Sea to southern, western and north-western Europe. Despite its diminishing area of distribution and potential pharmacological value, little is known about the ecophysiological features of this coastal species. We investigated the photosynthetic performance of G. flavum by measuring gas exchange, chlorophyll fluorescence, photosynthetic pigment concentration and leaf water content over the space of a year in a coastal habitat of SW Spain. We also measured the variation in total concentrations of nitrogen, phosphorus, sulphur, potassium, calcium and magnesium, in the leaves and soil, throughout the study period. G. flavum showed a high resistance to summer drought conditions which appeared to be due to the high degree of stomatal control. The potential photochemical efficiency of photosystem II showed minimum values during the winter, indicating that low temperatures can produce negative effects within the photosynthetic apparatus. However, the marked decline in net photosynthesis during the winter seems to be mainly related to a loss of metabolic activity. Although leaf nutrient concentrations were, in general, within the normal ranges, phosphorus availability seems to be limited by the high calcium concentrations detected in the soil of the study site. Our study points out the efficiency of the different physiological adaptations of this rare and endangered coastal species in coping with the strong seasonal variability of the Mediterranean climate.  相似文献   
998.
The Rio+20 summit of the United Nations in Brazil in 2012 committed governments to formulate a set of sustainable development goals (SDGs) that would be integrated into the Millennium Development Goals (MDGs) following its expiration in 2015. This decision has pushed sustainable development agenda into the limelight of development once again. Meanwhile, we note that the development agenda of many developing countries has been dominated by neoliberal orientation driven by market reforms, social inequality, and a move towards enhancing the economic competitiveness of the supply side of the economy. In this paper, we discuss the relationship between neoliberal economic agenda and sustainable development. We do so by examining how neoliberal policies of privatisation, trade liberalisation and reduction in governments spending stand to affect the attainment of sustainable development ideals and their implications on the post-2015 Sustainable Development Goals. The paper then suggests that relying solely on the mechanisms of the market in governing and allocating environmental resources is necessarily insufficient and problematic and therefore calls for a new approach—one which goes beyond just recognising the interdependency among social, environmental and economic goals and places issues of equity and addressing unfavourable power relations at the centre of interventions aimed at achieving the ideals of sustainable development.  相似文献   
999.
While rural transformations are nothing new in human history, current processes of rural change occur under multiple forces at an unprecedented pace, involving profound and unexpected changes in land use and users, and rapid transformations in the metabolic patterns of rural systems. The present special section aims to shed light on current drivers and pathways of rural change by analyzing, under a common conceptual and theoretical framework, examples of new ruralities that are emerging as responses across different world regions. Within this context, this introduction presents: (1) common research questions of the six presented cases of rural change; (2) the general theoretical and methodological framework of integrated assessment of societal metabolism adopted to analyze rural systems and (3) the main contributions and conclusions that could be drawn from six context-specific case studies from Asia, Latin America and Europe.  相似文献   
1000.
Experiments have been performed to evaluate the impact of weak permanent horizontal magnetic field of about 400 A/m on seed formation in the main magnetic orientation types of radish, the north-south (NS) and west-east (WE) types. The results show that external magnetic field exposure retards plant progression through all stages of ontogeny but does not alter the ratio of NS and WE types. Under its effect, the numbers of pods and seeds and seed weight decrease in the NS-type but increase in the WS-type plants. Therefore, external magnetic field acts as an ecological factor that differentiates the responses of radish plants depending on the type of their magnetic orientation. Differences in the sensitivity of plants to magnetic field exposure are explained by specific features of their physiological status.  相似文献   
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