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991.
Summary The biomass and productivity of a montane grassland of Garhwal Himalaya were estimated with the objectives to compare these
values of the dominant exotic species, Eupatorium glandulosum HBK. (Asteraceae) with other species, and to compare the sites more dominated by this species with other study sites. The
effect of dominance of this species on other species was undertaken because of its continuous spread in the grasslands of
the Garhwal Himalaya causing replacement of some native grasses and economically important herbaceous plants. Out of six study
sites, SW1, SW2, and NE1 were more dominated by Eupatorium glandulosum. Total net primary productivity (TNP) ranged from 1528.5 to 2163.4 g m−2 yr−1. Eupatorium glandulosum showed individual highest biomass on all the study sites, and the sites more dominated by this species showed higher values
of primary productivity, thereby reducing the biomass and production of other species on these sites. 相似文献
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993.
The numerous applications of dextrins resulting from the heating of potato starch with α-amino acids prompted me to check the thermal reactions of starch with hydroxy acids and their lactones, such as citric acid, lactic acid, tartaric acid, and coumarine. The course of reactions was observed by means of Simultaneous TG/DSC Thermal Analyser. The thermal reactions were carried out on convectional and microwave heating. The course of reactions under such conditions was compared and properties of resulting dextrins were recognized. The structure and properties of products were obtained from FTIR spectra, water solubility tests, and pH measurements. It was found, that hydroxy acids and/or products of their thermal transformations reacted with starch and/or resulting dextrins producing esters or crosslinking esterification of dextrins took place. The properties of new dextrins were presented in order to check, in further studies, their application for selective flotation of complex metal ores and their suitability as prebiotics. 相似文献
994.
Biodegradation of polymeric materials affect a wide range of industries, information on degradability can provide fundamental information facilitating design and life-time analysis of materials. Among the methods currently used in testing, traditional gravimetric and respirometric techniques are tailored to readily degradable polymeric materials mostly and polymer blends with biodegradable components, but they are not applicable to the new generation of engineering polymers which are relatively resistant to biodegradation. However, electrochemical impedance spectroscopy (EIS) has been tested for monitoring biodeterioration of high strength materials and the technique has very high sensitivity. A wide range of materials including electronic insulation polyimides, fiber-reinforced polymeric composites (FRPCs) and corrosion protective polyurethane coatings have been successfully measured under inoculation of degradative microorganisms using EIS. In addition, the mechanism of degradation of high strength polymers is mainly due to the presence of plasticizers in the polymer matrices. The information on various methods discussed in this review is intended to illustrate a suite of methods for those who are interested in testing biodeterioration of polymeric materials under different environmental conditions and in selecting appropriate techniques for specific applications. 相似文献
995.
Przemys?aw?Siemion Janusz?Kapu?niak Jacek?J.?Kozio?Email author 《Journal of Polymers and the Environment》2005,13(1):19-27
Thermally induced reaction of thiourea with potato starch was carried out with involvement of either conventional or microwave heating. Under applied reaction conditions conventional heating provided a higher degree of transformation. The course of reaction was complex. Thiourea reacted with starch but the reaction products underwent further decompositions. Dextrins contaminated with isothiocyanates were obtained. Not necessarily they underwent alpha-amylolysis more readily than original starch. 相似文献
996.
Jorge A.?ArgáezEmail author J.?Andrés Christen Miguel?Nakamura Jorge?Soberón 《Environmental and Ecological Statistics》2005,12(1):27-44
We introduce a methodology to infer zones of high potential for the habitat of a species, useful for management of biodiversity, conservation, biogeography, ecology, or sustainable use. Inference is based on a set of sites where the presence of the species has been reported. Each site is associated with covariate values, measured on discrete scales. We compute the predictive probability that the species is present at each node of a regular grid. Possible spatial bias for sites of presence is accounted for. Since the resulting posterior distribution does not have a closed form, a Markov chain Monte Carlo (MCMC) algorithm is implemented. However, we also describe an approximation to the posterior distribution, which avoids MCMC. Relevant features of the approach are that specific notions of data acquisition such as sampling intensity and detectability are accounted for, and that available a priori information regarding areas of distribution of the species is incorporated in a clear-cut way. These concepts, arising in the presence-only context, are not addressed in alternative methods. We also consider an uncertainty map, which measures the variability for the predictive probability at each node on the grid. A simulation study is carried out to test and compare our approach with other standard methods. Two case studies are also presented. 相似文献
997.
Peter Gajsek Dina Simuni? 《International journal of occupational safety and ergonomics》2006,12(2):187-194
The rapid growth of mobile communications has not only led to a rising number of mobile telephones. It has also made base stations essential for these services widespread on many roofs. However, not everyone is aware that working close to sources of high frequency electromagnetic fields (EMF), such as transmitter antennas for mobile phones, pagers and police, fire and other emergency services, can result in high EMF exposure. This paper deals with measurements and calculations of the compliance boundary for workers in one typical roof top base station setting according to EU Directive and other relevant EN standards. 相似文献
998.
Jerzy S?owikowski Marek D?wiarek Maria Konarska 《International journal of occupational safety and ergonomics》2006,12(4):369-377
The study aimed at verifying a hypothesis that supporting a visual signal of regulation deviation with an auditory one could improve the quality of regulation; the operator would have better information on machine operation. A special simulator was applied to follow-up tracking with a manual lever which controlled vertical movements of a cursor on a monitor screen. Simultaneously with visual information on screen, the operator was provided with an auditory deviation signal of pre-determined characteristics. 33 young males underwent the test. It was found that supporting a visual signal with an auditory one resulted in an improvement in the regulation quality by 5-6%, which proved synergy between those signals. The results may be used in designing tele- and servo-mechanisms, especially for remote control machinery, e.g., inspection robots or micromanipulators controlled by operators in a follow-up system. 相似文献
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1000.