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991.
Reed beds of Phragmites australis in the River Amudarya delta near the Aral Sea constitute permanent breeding areas of the Asian Migratory locust, Locusta migratoria migratoria. Every year, thousands of hectares are treated with broad-spectrum insecticides to prevent locust swarms from damaging crops in adjacent areas. To devise efficient locust monitoring and management plans, accurate and updated information about the spatial distribution of reeds is necessary. Given the vast geographic extent of the delta, traditional, ground survey methods are inadequate. Remotely sensed data collected by the MODIS sensor aboard the TERRA satellite provide a useful tool to characterize the spatial distribution of reeds. Multi-temporal MODIS data, collected at different times of the growing season, were used to generate spectral-temporal signatures for reeds and other land cover classes. These spectral-temporal signatures were matched with reed phenology. MODIS information was digitally classified to generate a land cover map with an overall accuracy of 74%. MODIS data captured 87% of the ground-verified reed locations. Estimates derived from MODIS data indicate that 18% of the study area was covered by reeds. However, high commission error resulted from misclassification of reeds mixed with shrubs class and shrubs class as reeds. This could have resulted in overprediction of the area covered by reeds. Additional research is needed to minimize the overlap between reeds and other vegetation classes (shrubs, and reed and shrub mix). Nevertheless, despite its relatively low spatial resolution (250 m), multi-temporal MODIS data were able to adequately capture the distribution of reeds. Instead of blanketing the fragile wetland ecosystem of the Amudarya delta with chemical anti-locust treatments, plant protection specialists can use this information to devise ecologically sound pest management plans aimed at reducing the adverse environmental impact in the zone of the Aral Sea ecological catastrophe. MODIS methodology to identify reed stands can be applicable to the Migratory locust habitats in other geographic areas.  相似文献   
992.
One of the most endangered species in tropical seas, Chelonia mydas (green turtles) prefer undisturbed sand beaches to lay their eggs. While Caretta caretta lays their eggs all over the Mediterranean beaches of Turkey, C. mydas nesting locations are limited with north-eastern site (Alata, Kazanli, Akyatan and Samandag) of the country and some beaches in Cyprus. Until 2003, no nesting place of both species between Akyatan and Samandag was recorded. From north to south, the beaches examined in 2003 summer are Arsuz, Konacik, Kale, Tr-H-3, Tr-H-2, and Tr-H-1 in addition to well-known and studied nesting beaches of sea turtle species in Hatay Province: Cevlik, Seyhhizir and Meydan. Since the Hatay Provincial Coast between Cevlik and Arsuz is hilly and no stabilized road is available, these small beaches were not known to have both C. mydas and C. caretta nests. Some physical and chemical sand properties, the number of nests belong to both species and selected nest specifications were investigated in this study. Kale Beach was found to be the most important nesting place in this less populated area. Based on results, Kale, Tr-H-3 and Tr-H-1 beaches were recorded to have high hatchling success.  相似文献   
993.
The influence of the colonization of salt marsh sediments with Halimione portulacoides was evaluated by analysing the fluorescent dissolved organic matter (FDOM) in sediment pore waters from a salt marsh at different depths. Cores of sediments at colonized and non-colonized sites were collected from a coastal lagoon (Ria de Aveiro, Portugal). The DOC content of extracted pore waters was determined and characterized by synchronous molecular fluorescence (Deltalambda=60nm) and UV-visible spectroscopies. The common practice of freezing sediment cores for further and later chemical investigation was shown not to be an appropriate methodology of sample preservation. On the contrary, freezing of extracted and filtered pore water seemed not to affect either the DOC content or the fluorescence properties of pore waters. Two types of fluorescent substances were found in the pore waters spectra; one corresponding to humic-like substances and another one resembling proteins. However, major differences were found in the spectra of pore waters depending on both depth and the presence/absence of vegetation colonization.  相似文献   
994.
Rice paddies are an important source of the greenhouse gas methane (CH4). Global methane emission estimates are highly uncertain and do not account for effects of interpolation or data resolution errors. This paper determines such scaling effects for the influence of soil properties on calculated CH4 emissions for the island of Java, Indonesia. The effects of different interpolation techniques, variograms and neighbor optimization were tested for soil properties by cross-validation. Interpolated organic carbon values were not significantly different from the original soil samples, in contrast to interpolated soil iron contents. Interpolation of soil properties coupled to a process-based model on CH4emissions led to a significant change in distribution of calculated CH4 emissions, i.e., the variance decreased. Effects of data resolution were examined by interpolating soil properties to derive data at different data resolutions and then calculating CH4 emissions by applying the process-based model at these resolutions. The soil properties did not differ significantly for different data resolutions, in contrast to calculated CH4 emissions. These scaling effects were caused by the combination of interpolation and a non-linear model. Real scaling effects may even be larger because small-scale variability was not accounted for. Scaling effects, including those caused by small-scale variability, have to be considered to achieve unbiased and less uncertain global CH4emissions estimates from rice paddies.  相似文献   
995.
996.
997.
Ultrasonography in a female fetus revealed cystic cervical hygroma, severe micrognathia, and vertebral and upper limb anomalies suggestive of cerebro-costo-mandibular syndrome (CCMS) which was diagnosed ultrasonographically at 16 weeks' gestation. The father is affected and presents with a Pierre Robin sequence, short stature and typical costovertebral anomalies. CCMS is a rare and severe disorder. The high frequency of sporadic cases, vertical transmission, and the excess of sibs affected via horizontal transmission suggest dominant autosomal mutation with possible germinal mosaicism. The vertical familial case detailed in the present report is a reminder of the high risk when one parent or one sibling is affected and the extreme variability of phenotype and costal ossification. Early prenatal ultrasound diagnosis is possible in a severely affected fetus. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   
998.
Meriç S  Kaptan D  Olmez T 《Chemosphere》2004,54(3):435-441
In this study, Reactive Black 5 (RB5) was removed from synthetic wastewater using Fenton's oxidation (FO) process. Experiments were conducted on the samples containing 100 and 200 mg l(-1) of RB5 to remove the dye toxicity. Seventy-five milligram per litre of RB5 caused 25% toxicity on 24-h born daphnids whereas 100 mg l(-1) of RB5 displayed 100% toxicity on Daphnia magna. The study was performed in a systematic approach searching optimum values of FeSO(4) and H(2)O(2) concentrations, pH and temperature. Optimum pH and temperature for 100 mg l(-1) of RB5 were observed as 3.0 and 40 degrees C, respectively, using 100 mg l(-1) of FeSO(4) and 400 mg l(-1) of H(2)O(2) resulted in 71% chemical oxygen demand (COD) and 99% color removal. For 200 mg l(-1) of RB5, 84% COD removal was obtained using 225 mg l(-1) of FeSO(4) and 1000 mg l(-1) of H(2)O(2) yielding 0.05 molar ratio at pH 3.0 and 40 degrees C. Color removal was also more than 99%. The optimum conditions determined in accordance with the literature data. The H(2)O(2) requirement seems to be related to initial COD of the sample. FeSO(4)/H(2)O(2) ratios found were not changed for both concentrations. The temperature affected the COD removal significantly at high degrees. Toxicity was completely removed for each concentration of RB5 at optimum removal conditions.  相似文献   
999.
Guibaud G  Comte S  Bordas F  Dupuy S  Baudu M 《Chemosphere》2005,59(5):629-638
This paper provides information on the metal complexation potential of extracellular polymeric substances (EPS), extracted from activated sludges and from eight pure cultures of bacteria isolated from the same activated sludge. The EPS extracted from pure bacteria cultures are mainly composed of proteins and low quantities of polysaccharides and uronic acids in comparison with EPS extracted from activated sludges. The EPS studied present two apparent pK(a) and the IR spectra show the presence of the same functional groups on all the EPS studied. The ability of EPS to complex Cd, Pb and Ni, was studied at pH 7 with Chau and Ruzic's models using polarography titration. All of the EPS exhibited a greater ability to complex Pb than Ni, Cd showing the weakest affinity overall. The EPS extracted from the pure cultures of bacteria were less able to complex the metals than that extracted from activated sludges. Literature data, IR data and EPS phosphorous content, supported by the EPS pK(a), revealed that carboxylic and phosphoric groups may play a major role in binding to metals at pH 7. This study underlines the importance of metal exposure in order for bacteria to secrete or modify EPS. After exposure, the EPS then exhibit the greatest capacity to bind metal in order to protect bacteria from harmful effects of heavy metals.  相似文献   
1000.
An experiment was carried out to decompose chlorinated dioxins (PCDDs, PCDFs) Chlorobenzenes, NOx and odourous compounds (H2S, CH4S, C2H6S2, C8H8, C2H6S, C2H4O, NH3) simultaneously using a catalyst in the MSW incineration plant. The experiments were conducted at temperatures from 200°C to 400°C and from 3000h−1 to 6000h−1 at space velocity. A catalyst containing V2O5 and WO3 on the basis of TiO2 is used, an oxidizing catalyst of the honeycomb type. The average decomposition efficiencis were 95%, 98%, 92% for PCDDs(48CDDs), PCDFs(48CDFs) and Chlorobenzenes(36CLBs) at a reaction temperature of 350°C and a space velocity of 3000h−1, more than 90% for NOx at a reactiont temperature of 300°C and more than 80% for odourous compounds at the reaction temperature of 300°C and a space velocity of 6000h−1. All those compounds were decomposed successfully with increasing contact time and surface. The rate-determing step was the chemical reaction of catalyst surface.  相似文献   
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