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401.
John D. Stark James F. Walter 《Journal of environmental science and health. Part. B》2013,48(5):685-698
Abstract The persistence of two insecticidally active compounds from the neem tree, azadirachtin A and B, was determined at two different temperatures (15 and 25°C) in the laboratory after application of the commercial neem insecticide, Margosan‐O, to a sandy loam soil. The influence of microbial activity on degradation was also examined by comparing autoclaved and non‐autoclaved soils also at 15 and 25°C. Temperature influenced degradation rates. The DT 50 (time required for 50% disappearance of the initial concentration) for azadirachtin A was 43.9 and 19.8 d for non‐autoclaved soil kept at 15 and 25°C, respectively. The DT 50 for azadirachtin B was 59.2 and 20.8 d for non‐autoclaved soil kept at 15 and 25°C, respectively. Microbial activity was also responsible for faster degradation because DT 50 ’s for autoclaved soil were much longer than for non‐autoclaved soils. DT 50 ‘s for azadirachtin A in autoclaved soil were 91.2 (15°C) and 31.5 d (25°C). DT50’s for azadirachtin B in autoclaved soil were 115.5 (15°C) and 42.3 d (25°C). Two degradation products of azadirachtin were detected, but were not identified. Higher levels of the two degradation products were detected in non‐autoclaved soil. 相似文献
402.
Assessing the impact of the Indian Ocean tsunami on households: a modified domestic assets index approach 总被引:1,自引:0,他引:1
Sudha Arlikatti Walter Gillis Peacock Carla S. Prater Himanshu Grover Arul S. Gnana Sekar 《Disasters》2010,34(3):705-731
This paper offers a potential measurement solution for assessing disaster impacts and subsequent recovery at the household level by using a modified domestic assets index (MDAI) approach. Assessment of the utility of the domestic assets index first proposed by Bates, Killian and Peacock (1984) has been confined to earthquake areas in the Americas and southern Europe. This paper modifies and extends the approach to the Indian sub‐continent and to coastal surge hazards utilizing data collected from 1,000 households impacted by the Indian Ocean tsunami (2004) in the Nagapattinam district of south‐eastern India. The analyses suggest that the MDAI scale is a reliable and valid measure of household living conditions and is useful in assessing disaster impacts and tracking recovery efforts over time. It can facilitate longitudinal studies, encourage cross‐cultural, cross‐national comparisons of disaster impacts and inform national and international donors of the itemized monetary losses from disasters at the household level. 相似文献
403.
Understanding the climate and its variability, in particular with regard to their socioeconomic impact, requires specific
measurements of precipitation and temperature and their circulations. This becomes more important in applications to diverse
systems. In order to improve knowledge about temporal changes and trends in temperature, we analyzed series of maximum and
minimum daily surface temperatures at eight reference stations in southeastern South America during variable periods, with
the longest periods of around 100 years. To study the evolution of the temperature series and to reduce the number of parameters,
a nonhierarchical cluster analysis was performed. The algorithm assigns each day to one of four groups: warm, wet, cold and
dry. Low frequency variations were found in these groups and their association with circulation structure, circulation patterns
and precipitation. We concluded that the set of wet days is one of the main factors driving secular variations of maximum
and minimum temperature and variations in precipitation. We also inferred that after 1920 till 1930, a low frequency oscillation
is observed in the form of linear trends (increase of warm days and decrease of cold days). 相似文献
404.
405.
Vigni Lorenza Li Daskalopoulou Kyriaki Calabrese Sergio Kyriakopoulos Konstantinos Parello Francesco Brugnone Filippo D’Alessandro Walter 《Environmental geochemistry and health》2022,44(7):2111-2133
Environmental Geochemistry and Health - Geothermal areas of Greece are located in regions affected by recent volcanism and in continental basins characterised by elevated heat flow. Many of them... 相似文献
406.
Chlorine position of chlorophenol isomers has a significant effect on the dechlorination kinetics of monochlorophenols, dichlorophenols, and trichlorophenols during Fenton oxidation. The effects have been evaluated by the rate constants of the dechlorination kinetic model developed in this study. It is found that the dechlorination rate of 3-CP is faster than that of 4-CP, which is faster than that of 2-CP. Since OH and Cl groups on the aromatic ring are ortho and para directors, the directory effect of OH and Cl groups enhances the dechlorination kinetics of 2-CP due to acceleration of the hydroxylation of 2-CP. Therefore, the dechlorination kinetics increases accordingly. For trichlorophenols (TCP), steric hindrance plays an important role during their dechlorination process. Specifically, the closer the chlorine atoms locate with each other on the aromatic ring, the more difficult the dechlorination processes will be. The dechlorination kinetics of dichlorophenols seems to be affected by both directory effect of OH and Cl groups and the effect of steric hindrance of chlorine atoms. The directory effect of OH and Cl groups on trichlorophenols decreases since the chlorine atom occupied the positions which are the most favorable for hydroxyl radical attack. 相似文献
407.
Walter Zerr 《Environmental Sciences Europe》2006,18(4):219-227
Goal, Scope and Background
Worldwide energy requirements are constantly increasing. Rising prices and the necessity to secure the future energy supply have led the decision-makers in politics and economy to focus on the more intensive use of their own resources. Before the background of possible climatic effects caused by the use of fossil energies, the use of renewable resources as primary energies, with its narrow C-circulation, have gained in importance, particularly in terms of economic aspects. The production of biogas is of specific interest here. It is a sensible ecological investment and a solid source of income for our agriculture.Material and Methods
The operator uses a complex biological system in a plant with high investment costs. An economic operation is only possible if the process parameters are optimized and the properties of the substrates and the co-ferments are known. For the important determination of the blogas potential, we present an efficient and robust system, which is easy to handle and low cost, that has been developed by the LHL and LLH at the Eichhof. This procedure enables one to make statements on the implementation dynamics and is also suited to judge the fermentation process depending on the size of particles, as the co-ferments are used in a practice-oriented consistency.Results
With the described fermentation apparatus you can not only assess the potential development of biogas and methane, but also the process of fermentation. The sum-graphs determined allow one to make conclusions on the implementation dynamics and, thus, on the optimization of the process. The advanced equipment makes it possible to determine the process of fermentation and the gas yield under different retention times and digester loads. The determination of the potential of the biogas and also the evaluation of the continuous fermentation are related to a specific correction factor won from the standard.Discussion
A prerequisite for economic process management is the knowledge of the attainable gas yield and the fermentation process of substrates and co-ferments. A precise calibration is the quality basis for the results achieved with this method, as is the case with other fermentation tests as well. For the tests, a highly homogeneous substrate, which guarantees a continuous biological activity in the digesters, ought to be used. The possibility of determining optimum retention times and digester loads with this equipment makes costly tests with a full scale reactor unnecessary.Conclusions
All tests run demonstrated that the fermentation apparatus originally developed to determine the biogas yield is absolutely suited to also assess the impact of different digester loads and retention times.Recommendations
The problem of the suitability and the potential of different materials, the optimum reactor performance and the combination of different processes of energy generation from renewable but also conventional resources will increaseingly become the focus of laboratory tests. The following subjects have to be taken into account:Perspective
These tests with a high practical relevance are supposed to contribute to a reliable method of producing biogas, in order to optimize the yield of gas production, but also to find a calibration of less costly procedures like those involving Near Infrared Spectroscopy (NIRS). 相似文献408.
409.
Sponges of warm- and temperate- but also cold-waters are known to synthesize structurally diverse primary and secondary metabolites.
These compounds fulfill a variety of functions including adaptations of the cell membranes to environmental conditions. We
show here that boreal sponges of the order Halichondrida are rich sources of brominated lipid fatty acids. The comparison
of lipid compositions of halichondrid Demospongiae from boreal and warmer waters indicates an accumulation of brominated fatty
acids in sponges from colder settings. Moreover, the spatial distribution of brominated fatty acids in the sponge tissue of
one widely distributed sponge of the North-East Atlantic (Phakellia ventilabrum) hints to a function related to membrane fluidity and permeability rather than to defense against predation. However, brominated
fatty acids are diagnostic for the presence of bromoperoxidases in sponges and may therefore be potentially useful as markers
in a chemical screening for secondary metabolites of pharmacological interest. 相似文献
410.