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91.
Trends in Hydrological Parameters of a Southern Brazilian Watershed and its Relation to Human Induced Changes 总被引:5,自引:1,他引:4
Moraes Jorge M. Pellegrino Giampaolo Q. Ballester Maria V. Martinelli Luiz A. Victoria Reynaldo L. Krusche Alex V. 《Water Resources Management》1998,12(4):295-311
The Piracicaba river basin is a subtropical watershed located in the southeastern region of Brazil. With an area of 12 400 km2, the basin is a typical example of new landscape resulting from development in tropical and sub-tropical regions: establishment of intensive industrial and agricultural processes were followed by significant population growth and water management. This scenario has led to significant increase in water demand and decrease in water quality. The main objective of this study is the detection of changes in the patterns of flow and precipitation in the basin, and its possible relation to man-induced changes. Statistical analyses were performed on records of precipitation, evapotranspiration and streamflow, from 1947 to 1991. Precipitation and evapotranspiration totals showed significant increasing trends for the entire basin. From eight streamflow gauge stations, half showed significant decreasing trend. The most probable cause of such trends is the export of water from the basin to the metropolitan region of São Paulo city. 相似文献
92.
Corporate investment myopia: a horserace of the theories 总被引:3,自引:0,他引:3
This paper tests two theories of corporate investment myopia which predict a distortion in investment policy with respect to the standard net present value rule. The theories are confronted with the empirical evidence, allowing the theories to compete to explain investment behavior. Research and development expense is used to proxy for long-term investment in a pooled, cross-sectional time-series regression. I find that research and development expense is decreasing in the age of the Chief Executive Officer. Results are consistent with the hypothesis that agency costs are lower when the firm invests myopically, rather than follow a standard net present value rule. 相似文献
93.
Stephen L. Liedtka 《Journal of Business Finance & Accounting》2002,29(7&8):1105-1121
This research extends the literature on nonfinancial performance measures (NFPMs) by assessing (1) the information content of a broader set of NFPMs and (2) whether NFPMs provide information not provided by financial performance measures (FPMs) from all previously identified FPM categories, rather than just earnings and book value. Specifically, exploratory and confirmatory factor analysis results presented in this paper demonstrate that nineteen NFPMs of major airlines capture seven underlying constructs not captured by eighteen common FPMs. Additionally, this research develops reliable composite measures of the identified performance measure constructs, which prior research argues are superior to individual performance measures. 相似文献
94.
Nitrification kinetics are important for process design, optimization, and capacity rating of activated sludge wastewater treatment plants. A Water Environment Research Foundation (WERF) project on Methods for Wastewater Characterization in Activated Sludge Modeling (WERF, 2003) focused significantly on the development of procedures for measuring the nitrifier maximum specific growth rate, micro(AUT). In addition, the importance of (and lack of data for) the nitrifier decay rate, b(AUT), was identified. This paper describes three bench-scale methods for measuring micro(AUT): the Low F/M SBR, Washout and High F/M methods. During the WERF project, the importance of pH and temperature control was investigated briefly; this paper summarizes further experimental work performed to address these issues. A summary of micro(AUT) measurements in a number of locations and using the different measurement techniques is provided. 相似文献
95.
P Navarro J Sarasa D Sierra S Esteban J L Ovelleiro 《Water science and technology》2005,51(1):113-120
Wine industry wastewaters contain a high concentration of organic biodegradable compounds as well as a great amount of suspended solids. These waters are difficult to treat by conventional biological processes because they are seasonal and a great flow variation exists. Photocatalytic advanced oxidation is a promising technology for waters containing high amounts of organic matter. In this study we firstly investigated the application of H2O2 as oxidant combined with light (artificial or natural) in order to reduce the organic matter in samples from wine industry effluents. Secondly, we studied its combination with heterogeneous catalysts: titanium dioxide and clays containing iron minerals. The addition of photocatalysts to the system reduces the required H2O2 concentration. Although the H2O2/TiO2 system produces higher efficiencies, the H2O2/clays system requires a H2O2 dosage between three and six times lower. 相似文献
96.
Performance of a combined eco-system of ponds and constructed wetlands for wastewater reclamation and reuse. 总被引:1,自引:0,他引:1
An on-site study on the operational performance of a combined eco-system of ponds and SF constructed wetland for municipal wastewater treatment and reclamation/reuse in Donging City, Shandong, China was carried out from January 2001 through October 2003. The removal efficiencies for various main parameters were: TSS 84.8 +/- 7.3%, BOD5 87.2 +/- 5.3%, CODCr 70.2 +/- 18.6%, TP 52.3 +/- 23.1%, and NH(3)-N 54.8 +/- 23.9% with effluent concentration of TSS 9.12 +/- 5.12 mg/l, BOD5 6.44 +/- 4.58 mg/l, CODCr, 42.8 +/- 6.7 mg/l, TP 0.94 +/- 0.27 mg/l and NH(3)-N 7.95 +/- 2.36 mg/l. In addition, the removal efficiencies for faecal coliforms and total bacteria were > 99.97% and > 99.998% respectively, which well meet Chinese National standards for effluent quality of municipal wastewater treatment plants. The composition of TSS was closely related to CODCr and BOD5 variations, and nitrification-denitrification is the major mechanism of nitrogen removal both in ponds and in wetlands. In addition, sedimentation also played an important role in the removal of TSS, nitrogen, phosphorus and BOD5. The removal efficiencies of various parameters, the number of species and biomass of biological community in the system increased gradually with the ecological maturation. 相似文献
97.
Ponds following anaerobic reactors, such as Upflow Anaerobic Sludge Blanket (UASB) reactors, have been termed polishing ponds in the literature. The present paper analyses the removal of E. coli and helminth eggs in five UASB-polishing pond systems in Brazil. Since there were ponds in series, the total number of ponds was 10. The ponds had average retention times varying from 2 to 21 days, and depths ranging from 0.40 to 2.00 m. The shallow ponds in series, even with low retention times, were able to produce effluents complying with the coliform WHO guidelines for unrestricted irrigation (< or = 1000 MPN/100 ml). An equation for the coliform decay coefficient was proposed: Kb (dispersed flow) = 0.710H(-0955) (20 degrees C). The equation highlights the inverse relationship between the pond depth and the decay coefficient. All polishing pond systems were able to produce effluents with helminth eggs concentrations predominantly equal to zero, and satisfying the WHO guidelines for unrestricted and restricted irrigation (< or = 1 egg/L, arithmetic mean). The approximate range of helminth eggs removal efficiency was predicted satisfactorily. 相似文献
98.
99.
100.
Summary. Combining a strategy model, an inference procedure and a new experimental design, we map sequences of observed actions in repeated games to unobserved strategies that reflect decision-makers’ plans. We demonstrate the method by studying two institutional settings with distinct theoretical predictions. We find that almost all strategies inferred are best responses to one of the inferred strategies of other players, and in one of the settings almost all of the inferred strategies, which include triggers to punish non-cooperators, are consistent with equilibrium strategies. By developing a method to infer unobserved repeated-game strategies from actions, we take a step toward making game theory a more applied tool, bridging a gap between theory and observed behavior.Received: 23 December 2002, Revised: 19 April 2005, JEL Classification Numbers:
C72, C80, C90.The authors are indebted for discussions with Ray Battalio, David Cooper, Robin Dubin, John Duffy, Ellen Garbarino, Susan Helper, Margaret Meyer, John Miller, Jim Rebitzer, Mari Rege, Al Roth, and John Van Huyck. The authors also benefited from discussants at economic department seminars at Case Western Reserve, McMaster and McGill University, University of Pittsburgh, SUNY-Stony Brook, and Texas A&M, and participants at the 2002 European Winter Meeting of the Econometric Society. We are grateful for the financial support provided by the Department of Economics at the University of Pittsburgh and Case Western Reserve University. 相似文献