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1.
Employing in-depth, elite interviews, this empirical research contributes to understanding the dynamics among policy windows, policy change, and organizational learning. First, although much of the research on agenda setting—how issues attract enough attention that action is taken to address them—has been conducted at the national scale, this work explores the subnational, regional scale. With decentralization, regional-scale environmental decision-making has become increasingly important. Second, this research highlights the role of policy windows and instances of related organizational learning identified by natural resources managers. Having practitioners identify focusing events contrasts with the more typical approach of the researcher identifying a particular focusing event or events to investigate. A focusing event is a sudden, exceptional experience that, because of how it leads to harm or exposes the prospect for great devastation, is perceived as the impetus for policy change.  相似文献   
2.
Wild rodents were collected using live snap traps in pistachio gardens of Kerman Province, Southeast Iran from 2007 to 2009, then some physiological parameters of them were measured. The samples were identified as follow: Nesokia indica, Meriones persicus, Meriones lybicus and Tatera indica. Blood samples were obtained from the heart, then the blood parameters (glucose, cholesterol, triglyceride, total protein, HDL, red and white blood cell number) in wild species of rodents and laboratory rat were compared. The results showed that there were no significant differences in serum glucose, triglyceride, HDL and total protein levels among different experimental groups. The concentration of cholesterol in T. indica was more than that in N. indica (P < 0.01). The total numbers of red blood cells also showed significant difference between wild garden rodent species and laboratory rat (P < 0.01), while the numbers of white blood cells showed no significant difference.  相似文献   
3.
Microzooplankton was sampled during two cruises (Galápagos Vents, March 1985; Tongue of the Ocean and western edge of the Sargasso Sea, October/November 1985) by various collection methods (Niskin bottles, plankton nets, divers) to determine the vertical distribution and abundance of Acantharia. The larger size classes of Protozoa are dominated by the sarcodines, and Acantharia are frequently the most abundant of these in mesotrophic and oligotrophic oceans. The absolute densities of Acantharia have been consistently underestimated in many previous studies for two reasons: their skeletons dissolve in preserved samples, and they are undersampled by fine-meshed plankton nets. The previously identified dissolution problem may be less severe for concentrated samples because the dissolution of a portion of the Acantharia will raise the dissolved strontium concentration in the sample. Twenty five and 160 m-mesh plankton nets consistently underestimate the abundance of net plankton by one to two orders of magnitude. Possible reasons for this significant error are discussed. In the Equatorial Pacific Ocean, Acantharia were found at densities as high as 30 liter-1 and integrated abundances of 1.58 to 5.34x105 Acantharia m-2. Up to 90% were concentrated near the surface; their abundance declined sharply below 20 m. At two stations in the Atlantic, peak densities reached 6.4 liter-1. Wind-mixing may spread individuals more evenly through the euphotic zone, but they reestablish their surface maximum during period of calm. Acantharia generally have relatively few, but large symbionts. Small individuals average about 6 symbionts per host, larger hosts average 40 symbionts, and some individuals may have thousands of algal cells. Acantharia symbionts made up less than 1% of the chlorophyll in the water column, even at their host's peak abundances of 30 liter-1. However, production estimates, using published sarcodine-symbiont production-rates, suggest that Acantharia could occasionally account for up to 20% or more of the carbon fixation in the upper euphotic zone of oligotrophic oceans.  相似文献   
4.
Confronting socially generated uncertainty in adaptive management   总被引:1,自引:0,他引:1  
As more and more organizations with responsibility for natural resource management adopt adaptive management as the rubric in which they wish to operate, it becomes increasingly important to consider the sources of uncertainty inherent in their endeavors. Without recognizing that uncertainty originates both in the natural world and in human undertakings, efforts to manage adaptively at the least will prove frustrating and at the worst will prove damaging to the very natural resources that are the management targets. There will be more surprises and those surprises potentially may prove at the very least unwanted and at the worst devastating. We illustrate how acknowledging uncertainty associated with the natural world is necessary but not sufficient to avoid surprise using case studies of efforts to manage three wildlife species; Hector's Dolphins, American Alligators and Pallid Sturgeon. Three characteristics of indeterminism are salient to all of them; non-stationarity, irreducibility and an inability to define objective probabilities. As an antidote, we recommend employing a holistic treatment of indeterminism, that includes recognizing that uncertainty originates in ecological systems and in how people perceive, interact and decide about the natural world of which they are integral players.  相似文献   
5.
Release of14C-labelled carbon dioxide from uniformly labelled cells was used to measure respiration by individual ciliates in 2-h incubations in 1989 and 1990. In a strictly heterotrophic ciliate,Strobilidium spiralis (Leegaard, 1915), release of labelled carbon dioxide was equivalent to ca. 2.8% of cell C h–1 at 20°C, and there was no difference between rates in the dark and light. In the chloroplast-retaining ciliatesLaboea strobila Lohmann, 1908,Strombidium conicum (Lohmann, 1908) Wulff, 1919 andStrombidium capitatum (Leegaard, 1915) Kahl, 1932, release of labelled carbon dioxide was less in the light than in the dark in experiments done at 15°C. InL. strobila release of radiolabel as carbon dioxide was equivalent to ca. 2.4% of cell C h–1 in the dark but ca. 1% at 50µE m–2 s–1, an irradiance limiting to photosynthesis. InS. conicum release of radiolabel as carbon dioxide was equivalent to ca. 4.4% of cell C h–1 in the dark, but at an irradiance saturating to photosynthesis (250 to 300µE m–2 s–1) there was no detectable release of labelled carbon dioxide. InS. capitatum release of radiolabel as carbon dioxide was equivalent to ca. 4.3% of cell C h–1 in the dark but at an irradiance saturating to photosynthesis was ca. 2.4% of cell C h–1. These data, combined with data from photosynthetic uptake experiments, indicate that14C uptake underestimates the total benefit of photosynthesis by 50% or more in chloroplastretaining ciliates.Contribution no. 7510 from the Woods Hole Oceanographic Institution  相似文献   
6.
The benefits of utilizing intermediaries to broker understanding between environmental scientists and policy makers have become widely touted. Yet little is known about the tasks boundary spanners undertake to develop environmental policy solutions and how these tasks fit into frameworks intended to advance public policy decision making. Such frameworks may be constructed to aid decision makers in differentiating between the types of environmental policy issues that confront them or the policy settings in which they are operating. Consequently, this paper examines how six different knowledge brokering strategies; informing, consulting, matchmaking, engaging, collaborating and building capacity might be employed in responding to different types of environmental policy problems or policy settings identified in decision aiding frameworks. Using real world examples, four frameworks are reviewed. They are; Lindquist's [Lindquist, E.A., 1988. What do decision models tell us about information use? Knowledge in Society 1 (2), 86–111; Lindquist, E.A., 1990. The third community, policy inquiry, and social scientists. In: Stephen Brooks, S., Gagnon, A. (Eds.), Social Scientists, Policy and the State. Praeger, New York; Lindquist, E.A., 2001. Discerning policy influence: framework for a strategic evaluation of IDRC-Supported research] decision regimes, Turnhout et al.’s [Turnhout, E., Hisschemoller, M., Eijsackers, H., 2007. Ecological indicators: between the two fires of science and policy. Ecological Indicators 7 (2), 215–228] science policy typology, Holling's [Holling, C.S., 1995. What barriers? What bridges? In: Gunderson, L.H., Holling, C.S. (Eds.), Barriers and Bridges to the Renewal of Ecosystems and Institutions. Columbia University Press, New York, pp. 3–34] adaptive cycle and Kurtz and Snowden's [Kurtz, C.F., Snowden, D.J., 2003. The new dynamics of strategy: sense-making in a complex and complicated world. IBM Systems Journal 42 (3), 462–483] Cynefin domains. For the different problem types or policy settings described in the decision aiding frameworks primary knowledge brokering strategies are identified. While the frameworks differ in their conceptual constructions, the applicability of specific knowledge brokering strategies serve as a commonality across particular problem types and policy settings.  相似文献   
7.
Spatial and temporal variation of resource limitation in Chesapeake Bay   总被引:7,自引:0,他引:7  
We report nutrient addition bioassays at 18 stations in Chesapeake Bay (USA) to assess resources limiting phytoplankton growth. Data were pooled from several sampling programs conducted from 1989 to 1994. Spatially, light and P limitation declined from low salinity regions to high salinity regions, as N limitation increased. This spatial pattern was driven primarily by freshwater inflows with high N/P and seawater inflows with low N/P. Seasonally, there was a marked progression of winter light limitation, spring P limitation, and summer N limitation at mesohaline and polyhaline stations. The seasonal pattern appeared to be caused by temperature, mixing, river discharge, and sediment P fluxes. At high salinity stations, we also observed winter N limitation (caused by DIN depletion prior to spring nitrate delivery), and at lower salinity stations there was fall P limitation (caused by reaeration of bottom sediments). At tidal fresh stations, turbidity and nutrient concentrations resulted in continuous light limitation, except at some stations in summer. Interannual decreases in light limitation and increases in N and P limitation appear to represent improvements in water quality. Received: 31 October 1997 / Accepted: 18 December 1998  相似文献   
8.
Policy windows are transitory opportunities during which the likelihood of adopting new policy or legislative proposals is greater than usual. Accepted wisdom has held that natural disasters serve as focusing events that generate policy windows in their wake. This paper highlights the need for a more circumscribed understanding of when and where policy windows occur based on the experiences of three US regional planning organizations: a hand-picked commission of community leaders, a council of governments, and a special-purpose substate organization. The first operated in the San Francisco Bay Area of California following the Loma Prieta earthquake (October 1989), and the other two in South Carolina's Atlantic coastal plain after Hurricane Hugo (September 1989). The analysis concludes that natural disasters did not transform the agenda or mission of these entities. Policy windows were neither automatic outcomes of focusing events nor did they ensure the adoption of pertinent policy within the organizations investigated. Several conditions are minimally necessary for using policy windows to bring about hazard mitigation: comprehensive institutional conceptualization of hazards management, institutional strength and flexibility, and well-placed, effective policy entrepreneurs.  相似文献   
9.
Obligate mixotrophy inLaboea strobila,a ciliate which retains chloroplasts   总被引:2,自引:0,他引:2  
The planktonic ciliateLaboea strobila Lohmann sequesters photosynthetically functional chloroplasts derived from ingested algae. The chloroplasts lie free in the cytoplasm and are most abundant just under the pellicle of the ciliate. The maximum rate of photosynthesis (Pmax) was 925 pg C ciliate-1h-1 (3.7 pg C pg chl.a -1h-1). At saturating irradiance, the amount of carbon fixed h-1 equaled 12.6% of the body carbon of the ciliate. To grow,L. strobila requires both light and algal food. In the absence of food, survival ofL. strobila is significantly longer in the light than in the dark. Based on ingestion rate and photosynthetic rate, we calculate that photosynthesis can make an important contribution to this ciliate's carbon budget even when algal food is plentiful.  相似文献   
10.
This study models and assesses the significance of risks to health potentially posed to individuals exposed to volatile organic compounds (VOCs) due to being occupationally engaged in cleaning petroleum storage tanks. Exposure processes include hydrocarbon vapor inhalation, ingestion via hand-to-mouth contact, and dermal exposure. Under confined space entry regulations, tank cleaners must wear protective clothing and a breathing apparatus. However, such regulations are recent and sometimes violated. Several factors were found to influence exposure of unprotected individuals cleaning tanks. One factor is climate. This paper reports on a study of tanks in south Texas, which is sunny and hot during most of the year. Solar irradiation of metal surfaces may elevate internal temperatures above ambient air temperatures. Vaporization then elevates airborne hydrocarbon concentrations, and ventilation reduces them, producing a dynamic equilibrium. Human entry, however, disturbs this equilibrium by agitating petroleum residuals. Based upon the above considerations, we have modeled petroleum fuel storage tank dynamics in a case study. We considered three cases: manways closed, manways open, and manways actively ventilated. For CASE I, the concentration of each pollutant in the vapor phase was calculated using Raoult's Law. CASE II and CASE III applied Raoult's Law and also evaluated a mass balance via a mass transfer coefficient derived using the Reynolds Number and the Schmidt Number. Based upon empirical data, the velocity of the air within the tank was assumed to be 1.6 mph. Outputs of the case study included the steady-state concentration of each constituent and time required to reach it. Health risk assessment was conducted to quantify non-cancer risks posed by individual substances (the hazard quotient, HQ) and by simultaneous and/or sequential exposure to multiple substances (the hazard index, HI). During hot months, gross exceedances of acceptability criteria for acute and chronic exposures to mixed solvent vapors occurred. The HI exceeded the acceptability criterion by more than three orders of magnitude. The HI for chronic occupational neurological risks exceeded the acceptability criterion by more than two orders of magnitude. This result is consistent with observed neurological deficits among tank cleaners, such as depression of performance on memory tests among crew members who had worked during hot months. Finally, in such instances, eight-hour time-weighted average mixed-solvent vapor concentrations can exceed half of lethal levels, suggesting that tank cleaners can potentially approach lethal exposure routinely during hot seasons.  相似文献   
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