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51.
Montane Meadows as Indicators of Environmental Change 总被引:1,自引:0,他引:1
Diane M. Debinski Mark E. Jakubauskas Kelly Kindscher 《Environmental monitoring and assessment》2000,64(1):213-225
We used a time series of satellite multispectral imagery for mapping and monitoring six classes of montane meadows arrayed along a moisture gradient (from hydric to mesic to xeric). We hypothesized that mesic meadows would support the highest species diversity of plants, birds, and butterflies because they are more moderate environments. We also hypothesized that mesic meadows would exhibit the greatest seasonal and interannual variability in spectral response across years. Field sampling in each of the meadow types was conducted for plants, birds, and butterflies in 1997 and 1998. Mesic meadows supported the highest plant species diversity, but there was no significant difference in bird or butterfly species diversity among meadow types. These data show that it may be easier to detect significant differences in more species rich taxa (e.g., plants) than taxa that are represented by fewer species (e.g., butterflies and birds). Mesic meadows also showed the greatest seasonal and interannual variability in spectral response. Given the rich biodiversity of mesic montane meadows and their sensitivity to variations in temperature and moisture, they may be important to monitor in the context of environmental change 相似文献
52.
53.
Michael A. Mallin Mary I. Haltom Bongkeun Song Mary E. Tavares Stephen P. Dellies 《Journal of environmental management》2010,91(12):2748-2753
Fecal contamination of water bodies causes a public health problem and economic loss. To control such contamination management actions need to be guided by sound science. From 2007–2009 a study was undertaken to determine the sources of fecal bacteria contamination to the marine waters adjoining the Town of Wrightsville Beach, North Carolina, USA. The research effort included sampling for fecal coliform and Enterococcus bacteria, sampling for optical brighteners, dye studies, and use of molecular bacterial source tracking techniques including polymerase chain reaction (PCR) and terminal restriction fragment polymorphism (T-RFLP) fingerprinting of the Bacteroides–Prevotella group. Of the 96 samples collected from nine locations during the study, the water contact standard for Enterococcus was exceeded on 13 occasions. The T-RFLP fingerprint analyses demonstrated that the most widespread source of fecal contamination was human, occurring in 38% of the samples, with secondary ruminant and avian sources also detected. Optical brightener concentrations were low, reflecting a lack of sewage line leakage or spills. A lack of sewer leaks and lack of septic systems in the town pointed toward discharge from boat heads into the marine waters as the major cause of fecal contamination; this was supported by dye studies. Based on these data, the Town initiated action to have the U.S. Environmental Protection Agency declare the coastal waters (out to 3 nautical miles), the nearby Atlantic Intracoastal Waterway and its tributaries a no-discharge zone (NDZ) to alleviate the human fecal pollution. The Town garnered supporting resolutions from other local communities who jointly petitioned the North Carolina Department of Environmental and Natural Resources. This State regulatory agency supported the local government resolutions and sent an application for an NDZ to the EPA in April 2009. The EPA concurred, and in February 2010 the coastal waters of New Hanover County, NC, became the first marine area on the U.S. eastern seaboard between Delaware and the Florida Keys to be declared a no-discharge zone. 相似文献
54.
Gabriel Meneghetti Faé Gomes Talita Furlanetto Mendes Keiko Wada 《Journal of Cleaner Production》2011,19(9-10):1096-1103
This paper focuses on the improvement of a secondary lead recycling processing plant, giving special attention to the generation of lead slag. The study was conducted using two different industrial rotary furnaces that together produce three different slag types, which depend on charge composition and lead-containing raw material obtained from a lead-acid battery recycling process. First, characterization of three slag types from different batches was performed, and such characterization included chemical, mineralogical, and structural analyses. By analyzing these data and the operational conditions of the process, it was possible to identify certain deficiencies in the recycling process and implement modifications in order to improve it. A reduction of up to 25% in the quantity of slag generated could be achieved with certain charges. In addition to this process improvement, it was possible to reduce the toxicity of the slag produced when processing a charge containing the same proportion of paste and grid as the lead-acid battery. This improvement lessens the overall environmental impact of the process. By applying this methodology, it was possible to determine some principles of cleaner production in the lead recycling process. So, waste generation could be reduced via improvements in the process and slag characteristics were modified to decrease its toxicity (as determined by lead content in leaching tests). 相似文献
55.
Elaine S. Carvalho Rubén J. Sánchez Maria I. B. Tavares álano C. Lam?nica 《Journal of Polymers and the Environment》2010,18(4):661-667
The chemical modification of Acrylamidomethyl Cellulose Acetate Propionate (AMCAP) was carried out by radical addition of
acrylic acid. The structural modification was confirmed with the aid of FTIR, MS and NMR techniques. Thermal properties of
hydrophilic cellulose derivative (AMCAP–H2O2) such as glass transition (Tg 153 °C) and thermal stability (372.7 °C) were determined by DSC and TGA techniques, respectively. These thermal properties
confirmed the introduction of carboxylic groups into AMCAP structure, which causes an impact in their properties. The AMCAP–H2O2 shows minor contact angle compared to AMCAP, giving a more hydrophilic characteristic, due to acrylic acid addition into
the side chains of AMCAP polymer. 相似文献
56.
Predictive value of cardiovascular parameters in stages 1 and 2 of twin-to-twin transfusion syndrome
57.
Kelly M. Cobourn Hannah J. Burrack Rachael E. Goodhue Jeffrey C. Williams Frank G. Zalom 《Journal of Environmental Economics and Management》2011,62(2):278-289
A modeler must often rely on highly simplified representations of complex physical systems when analyzing associated economic issues. Herein, we consider a management problem in which a bioeconomic system exhibits simultaneity in processes governing productivity and damage. In this case, it may benefit the producer to sacrifice productivity to reduce the costs associated with increased damage. We specify empirically a structural damage relationship that explains the biological process by which an invasive species damages a host and estimate the structural model and its reduced form with an exceptional dataset on infestation of olives by the olive fruit fly. We contrast the results of these models with the approach typically taken in the economic literature, which expresses damage as a function of pest density. The population-based approach introduces significantly greater bias into the individual grower's choice of damage-control inputs than estimates based on the structural model. 相似文献
58.
Kelly A. Stiver Stephen H. Wolff Suzanne H. Alonzo 《Behavioral ecology and sociobiology》2012,66(6):855-864
While extensive empirical and theoretical work has focused on the evolution of costly cooperation (particularly in group-living species), less attention has been paid to more low-risk or immediately beneficial forms of cooperation. In some non-group-living darters, alloparental care (or allocare) by subordinates has been noted to result from by-product benefits as small territorial (subordinate) males adopt and provide care to the abandoned eggs of large territorial (dominant) males. In the tessellated darter (Etheostoma olmstedi), allocare also results from sneak fertilization. However, information on the rate of allocare by tessellated darters is contradictory: prior behavioral work suggested that it is very common, while a genetic examination showed males to primarily care for their own young. We found behavioral and genetic evidence of very high levels of allocare at our study location. The relative size of the assigned fathers of young to the alloparental male is consistent with the idea that initial allocare primarily results from sneak fertilization (“cuckoldry-based allocare”), but later allocare results from subordinate males caring at previously abandoned nests (“adoption-based allocare”). Larger males appeared to breed more frequently at different nests, but did not father more individual offspring than smaller males. Finally, low relatedness between abandoning and alloparenting males suggests that kin selection does not contribute to alloparental care. We discuss how variation in nest availability may explain the inconsistent findings of the rate of alloparental care in the tessellated darter, and how increased research in this and similar systems can expand our understanding of the evolution of cooperation. 相似文献
59.
60.
Vitas M Smith KE Plavec J Kesselmeier J Pajic T Ferlan A Zigon RD Kelly SL Komel R 《Chemosphere》1999,38(4):853-863
We investigated the hypothesis that the endogenous role of the commercially important inducible steroid hydroxylase cytochrome P450s of fungi was in defense against plant toxophores/secondary metabolites. Two plant defense compounds, the aglycones tomatidine and solanidine, the steroidal glycoalkaloid alpha-tomatine and the triterpene saponin beta-escin were tested as inducers of 11beta/14alpha-steroid hydroxylase in the filamentous fungus Cochliobolus lunatus. The extracts of saponins from the roots of Primula veris and green oat leaves were also tested as inducers of 11beta/14alpha-hydroxylation activity in progesterone biotransformation with the same fungus. Induction of steroid hydroxylase and inhibition of activity in some cases support our hypothesis that their endogenous function is in biochemical defence against secondary metabolites. 4-Pregnene-3,11,20-trione was added as a substrate for biotransformation with C. lunatus. We isolated from culture broth 14alpha-hydroxy-4-pregnene-3,11,20-trione, and the hitherto unreported compounds, 7alpha,14alpha-dihydroxy-4-pregnene-3,11,20-trione and 7alpha-hydroxy-pregna-4,8(14)-diene-3,11,20-trione. 相似文献