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Five cases of intestinal atresia were diagnosed using real-time ultrasonography following clinical evidence of polyhydramnios. No correlation was noted between ultrasound findings and the severity of the lesions. Two of the five babies died at 35 and 77 days respectively. Prematurity and presence of other abnormalities were factors in the deaths. 相似文献
265.
Patrick R. Zimmerman Maribeth Price Changhui Peng William J. Capehart Karen Updegraff Patrick Kozak Lee Vierling Elaine Baker Fred Kopp Genet Duke Chandan Das 《Mitigation and Adaptation Strategies for Global Change》2005,10(2):307-331
The C-Lock system was developed to address the need for an improved method of quantifying and certifying project-level carbon emission reduction credits (CERC). It was designed to enable individual landowners to efficiently quantify, certify, pool, market and trade CERCs generated by agricultural management practices. We provide a general overview of the C-Lock system as it has been implemented for the USA State of South Dakota. C-Lock is comprised of four linked components: a web interface, a client database, a Geographic Information System (GIS) database of soil, climate and generalized land use history parameters, and the CENTURY soil carbon model. The user-friendly interface elicits generalized land-use and crop history information from the client from 1900 through 1989, then explicit annual information from 1990 onward. A climate-zone level landuse and crop management database is used to fill in gaps in the client-provided data. These data are used to drive the CENTURY model, which estimates annual changes in soil carbon stocks. Monte Carlo simulation is used to estimate uncertainty bounds, and these are applied to the CENTURY outputs in order to provide probabilistic estimates of accrued CERCs in a manner that is transparent and verifiable. In a demonstration application, CERCs are estimated for three different land-use scenarios on a representative field in eastern South Dakota: reduced tillage or conservation (no-till) management of a corn (maize)/wheat/soybean rotation, and enrollment in the Conservation Reserve Program, which entails establishing permanent grass cover. The credits are based on a business-asusual scenario of conventional tillage. 相似文献
266.
This study demonstrates that ultrasound rapidly degrades the energetic compounds RDX (cyclo-1,3,5-trinitramine-2,4,6-trimethylene) and ADN (ammonium dinitramide) in aqueous microheterogeneous media. The conditions for effective degradation of these nitramines, as monitored by UV absorption spectroscopy, were determined by varying sonication time, the heterogeneous phase and its suspension density, and the concentration of NaOH. In the presence of 5 mg/ml of aluminum powder and at pH approximately 12 (10 mM NaOH), 74% of the RDX and 86% of the ammonium dinitramide (ADN) in near-saturated solutions decompose within the first 20 min of sonication (20 kHz; 50 W; < or =5 degrees C). Sonication without Al powder and base yields minimal degradation of either RDX and ADN (approximately 5-10%) or the nitrite/nitrate ions that are expected byproducts during RDX and ADN degradation. Sonication at high pH in the presence of dispersed aluminosilicate zeolite, alumina, or titanium dioxide also yields minimal degradation. Preliminary electrochemical studies and product analyses indicate that in situ ultrasonic generation of metallic aluminum and/or aluminum hydride drives reductive denitration of the nitramines. Sonochemical treatment in the presence of a reductant offers an effective and rapid waste remediation option for energetic waste compounds. 相似文献
267.
Niagolova N McElmurry SP Voice TC Long DT Petropoulos EA Havezov I Chou K Ganev V 《Environmental pollution (Barking, Essex : 1987)》2005,134(2):229-237
This study explored two hypotheses relating elevated concentrations of nitrogen species in drinking water and the disease Balkan Endemic Nephropathy (BEN). Drinking water samples were collected from a variety of water supplies in both endemic and non-endemic villages in the Vratza and Montana districts of Bulgaria. The majority of well water samples exceeded US drinking water standards for nitrate + nitrite. No statistically significant difference was observed for any of the nitrogen species between villages classified as endemic and non-endemic. Other constituents (sodium, potassium and chloride) known to be indicators of anthropogenic pollution were also found at elevated concentrations and all followed the order wells > springs > taps. This ordering coincides with the proximity of human influences to the water sources. Our results clearly establish an exposure pathway between anthropogenic activity and drinking water supplies, suggesting that the causative agent for BEN could result from surface contamination. 相似文献
268.
Photochemical transformations (lambda-254 nm) of 2,4-dinitrotoluene (2,4-DNT) in aqueous solutions containing the cationic surfactant cetyltrimethylammonium (CTA) and the anionic nucleophile borohydride (BH4-) were investigated. The overall decay rate was enhanced at CTA concentrations above the critical micelle concentration (cmc) when stoichiometric excess BH4- was present in solution. A kinetic model that separates the overall reaction rate into micellar and aqueous pseudo-phase components indicates transformation in micelles is 17 times faster that in the homogeneous water phase under those conditions investigated. Intermediate products were identified by comparing the HPLC retention times and ultraviolet-visible absorption spectra of product peaks to those of analytical standards. 2-Methyl-5-nitroaniline, 4-nitrotoluene, 2-nitrotoluene, 4-methyl-3-nitroaniline, 2,4-diaminotoluene, o-toluidine, 1,3-dinitrobenzene, 3-nitroaniline, p-cresol, and 2,4-diaminophenol were identified as photo-transformation intermediates or products. 相似文献
269.
Hoff PT Van Campenhout K Van de Vijver K Covaci A Bervoets L Moens L Huyskens G Goemans G Belpaire C Blust R De Coen W 《Environmental pollution (Barking, Essex : 1987)》2005,137(2):324-333
A perfluorooctane sulfonic acid (PFOS) assessment was conducted on gibel carp (Carassius auratus gibelio), carp (Cyprinus carpio), and eel (Anguilla anguilla) in Flanders (Belgium). The liver PFOS concentrations in fish from the Ieperlee canal (Boezinge, 250-9031 ng/g wet weight, respectively) and the Blokkersdijk pond (Antwerp, 633-1822 ng/g wet weight) were higher than at the Zuun basin (Sint-Pieters-Leeuw, 11.2-162 ng/g wet weight) and among the highest in feral fish worldwide. Eel from the Oude Maas pond (Dilsen-Stokkem) and Watersportbaan basin (Ghent) had PFOS concentrations ranging between 212 and 857 ng/g wet weight. The hepatic PFOS concentration was significantly and positively related with the serum alanine aminotransferase activity, and negatively with the serum protein content in eel and carp. The hepatic PFOS concentration in carp correlated significantly and negatively with the serum electrolyte concentrations whereas a significant positive relation was found with the hematocrit in eel. Although 13 organochlorine pesticides, 22 polychlorinated biphenyl (PCB) congeners and 7 polybrominated diphenyl ethers (PBDEs) were also measured in the liver tissue, only PCB 28, PCB 74, gamma-hexachlorocyclohexane (gamma-HCH) and hexachlorobenzene (HCB) were suggested to contribute to the observed serological alterations in eel. 相似文献
270.
D.H.?WardropEmail author J.A.?Bishop M.?Easterling K.?Hychka W.?Myers G.P.?Patil Charles?Taillie 《Environmental and Ecological Statistics》2005,12(2):209-223
The Atlantic Slope Consortium (ASC) is a project designed to develop and test a set of indicators in coastal systems that are ecologically appropriate, economically reasonable, and relevant to society. The suite of indicators will produce integrated assessments of the condition, health and sustainability of aquatic ecosystems based on ecological and socioeconomic information compiled at the scale of estuarine segments and small watersheds. The research mandate of the ASC project is the following:
Using a universe of watersheds, covering a range of social choices, we ask two questions:
As a basis for compiling ecological indicators, a watershed classification system was required for the experimental design. The goal was to develop approximately five categories of watersheds for each physiographic province, utilizing landscape and land use parameters that would be predictive of aquatic resource condition. All 14-digit Hydrologic Unit Code (HUC) watersheds in the Mid-Atlantic region would then be classified according to the regime. Five parameters were utilized for the classification: three land cover categories, consisting of forested, agricultural, and urban, median slope or median elevation, and total variance of land covers in 1-km-radius circles positioned on all stream convergence points in a specified 14-digit?HUC watershed. Cluster analysis utilizing these five parameters resulted in approximately five well-defined watershed classes per physiographic province. The distribution of all watersheds in the Mid-Atlantic region across these categories provides a unique report on the probable condition of watersheds in the region. 相似文献
- ? How “good” can the environment be, given those social choices?
- ? What is the intellectual model of condition within those choices, i.e., what are the causes of condition and what are the steps for improvement?