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41.
ABSTRACTLessons from the literature on multi-stakeholder dialogue (MSD) that are relevant to the debate on climate engineering (CE) are examined. MSDs have been used to prod slow-to-develop intergovernmental regulatory processes on a range of transnational and global controversies. A CEMSD might push forward anticipatory governance of CE by promoting social learning, sharpening and legitimizing governance norms, and starting to arrange the political space for governance by states. However, significant challenges and risks are also identified, including questions about the ripeness of the issue for stakeholder dialogue; difficult trade-offs in the design of dialogues, particularly around issues of participation and knowledge-power; and inherent tensions in the various purposes a CEMSD might serve. Given these challenges, steps forward that would better prepare a space for legitimate and effective dialogue are recommended. 相似文献
42.
Wilkins K Larsen K Simkus M 《Environmental science and pollution research international》2003,10(4):206-208
Since volatile mold metabolites are used for the detection of mold growth in buildings, it was interesting to determine whether different indoor mold species show different affinity for the major components of wood, a common building material. Growth and volatile metabolites were studied when Aspergillus versicolor, Penicillium chrysogenum, and P. palitans were grown on laboratory substrates containing the major wood constituents cellulose, xylan and lignin. Microbial volatile organic compounds (MVOCs) were characterized by thermal desorption/gas chromatography/mass spectroscopy. Growth and volatile metabolites varied considerably and there appeared to be complementary substrate specificities for P. chrysogenum, and P. palitans grown on cellulose and xylan. The failure of A. versicolor to produce characteristic MVOCs when grown on media containing wood constituents suggests that systems using volatile metabolites to detect microbial growth in buildings may be fundamentally unreliable for the detection of this species. 相似文献
43.
Nine amino acids, i.e., alanine, threonine, cysteine, glutamic acid, arginine, proline, tryptophan, phenylalanine and tyrosine, were irradiated with UV light in water containing nitrite or nitrate ion under neutral conditions. The mutagenicities of the ether extracts and the residual water layers of the reaction mixtures were assayed with and without S-9 mix using TA98 and TA100. Three aromatic amino acids, tryptophan, phenylalanine and tyrosine, were found to give direct-acting and frameshift mutagens by irradiation in aqueous nitrite solution. Among them, the ether extract of tryptophan exhibited the strongest mutagenicity toward TA98. In the case of irradiation in aqueous nitrate solution, only the ether extract of tryptophan exhibited weak mutagenicity toward TA98 without S-9 mix. The effects of nitrite concentration, irradiation time and pH on mutagen formation from tryptophan and some characteristics of the produced mutagens were examined. 相似文献
44.
Zhu J Cao XL Pigeon R Mitchell K 《Journal of the Air & Waste Management Association (1995)》2003,53(1):67-76
Three diesel fuels, one oil sand-derived (OSD) diesel serving as base fuel, one cetane-enhanced base fuel, and one oxygenate [diethylene glycol dimethyl ether (DEDM)]-blended base fuel, were tested for their emission characterizations in vehicle exhaust on a light-duty diesel truck that reflects the engine technology of the 1994 North American standard. Both the cetane-enhanced and the oxygenate-blended fuels were able to reduce regulated [CO, particulate matter (PM), total hydrocarbon (THC)] and nonregulated [polyaromatic hydrocarbons (PAHs), carbonyls, and other volatile organic chemicals] emissions, except for nitrogen oxides (NO(x)), compared with the base fuel. Although burning a fuel that contains oxygen could conceivably yield more oxygenated compounds in emissions, the oxygenate-blended diesel fuel resulted in reduced emissions of formaldehyde along with hydrocarbons such as benzene, 1,3-butadiene, and PAHs. Reductions in nitro-PAH emissions have been observed in both the cetane-enhanced and oxygenated fuels. This further demonstrates the benefits of using a cetane enhancer and the oxygenated fuel component. 相似文献
45.
Chris R. Pavey Chris J. Burwell Gerhard Körtner Fritz Geiser 《Die Naturwissenschaften》2009,96(6):679-683
One of the energetic benefits of daily torpor over prolonged hibernation is that it enables animals to regularly forage and,
therefore, replenish food reserves between bouts of torpor. However, little is known about the diet of predators undergoing
torpor or whether differences in prey composition among individuals influence torpor characteristics. Here, we test the hypothesis
that prey composition affects winter torpor use and patterns of a population of carnivorous marsupial, the brush-tailed mulgara
(Dasycercus blythi), in the Great Sandy Desert, Australia. Mulgaras in the study population captured a wide range of prey including vertebrates
(mammals, reptiles, birds), seven insect orders, spiders and centipedes. The proportion of vertebrates in the diet was negatively
correlated with both frequency of torpor use and maximum bout duration. This variation in torpor use with diet can be explained
by the higher energetic content of vertebrates as well as their larger size. Even assuming uniform intake of prey biomass
among individuals, those that subsisted on an invertebrate-dominated diet during winter apparently suffered energetic shortages
as a result of the scarcity of invertebrate taxa with high energy content (such as insect larvae). Our study is the first
to demonstrate a link between diet composition and daily torpor use in a free-ranging mammal. 相似文献
46.
Ken Sasaki Kazuhisa Yamasaki Koji Tsuchida Takashi Nagao 《Die Naturwissenschaften》2009,96(5):625-629
In social insects, biogenic amines are thought to play regulatory roles in the transition between reproductive states in females.
To determine the effect of dopamine on the reproductive development of workers in primitively eusocial societies, isolated
workers of the paper wasp Polistes chinensis were supplied with oral dopamine. Ovarian development was accelerated in dopamine-fed workers as compared to control workers
of the same age fed only sucrose solution. Oral dopamine increased brain levels of dopamine and its metabolite (N-acetyldopamine). Brain levels of tyramine or octopamine were also increased by dopamine application in one of two colonies;
levels of the tyramine metabolite N-acetyltyramine were unchanged. These results indicate that dopamine plays a gonadotropic role in isolated workers in the
primitively eusocial wasp, similar to the gonadotropic role previously reported for juvenile hormone. This is the first study
to report effects of dopamine on ovarian development in workers of the paper wasp. 相似文献
47.
48.
Physical and Chemical Connectivity of Streams and Riparian Wetlands to Downstream Waters: A Synthesis 下载免费PDF全文
Ken M. Fritz Kate A. Schofield Laurie C. Alexander Michael G. McManus Heather E. Golden Charles R. Lane William G. Kepner Stephen D. LeDuc Julie E. DeMeester Amina I. Pollard 《Journal of the American Water Resources Association》2018,54(2):323-345
Streams, riparian areas, floodplains, alluvial aquifers, and downstream waters (e.g., large rivers, lakes, and oceans) are interconnected by longitudinal, lateral, and vertical fluxes of water, other materials, and energy. Collectively, these interconnected waters are called fluvial hydrosystems. Physical and chemical connectivity within fluvial hydrosystems is created by the transport of nonliving materials (e.g., water, sediment, nutrients, and contaminants) which either do or do not chemically change (chemical and physical connections, respectively). A substantial body of evidence unequivocally demonstrates physical and chemical connectivity between streams and riparian wetlands and downstream waters. Streams and riparian wetlands are structurally connected to downstream waters through the network of continuous channels and floodplain form that make these systems physically contiguous, and the very existence of these structures provides strong geomorphologic evidence for connectivity. Functional connections between streams and riparian wetlands and their downstream waters vary geographically and over time, based on proximity, relative size, environmental setting, material disparity, and intervening units. Because of the complexity and dynamic nature of connections among fluvial hydrosystem units, a complete accounting of the physical and chemical connections and their consequences to downstream waters should aggregate over multiple years to decades. 相似文献
49.
Sediment-laden turbulent flows are commonly encountered in natural and engineered environments. It is well known that turbulence generates fluctuations to the particle motion, resulting in modulation of the particle settling velocity. A novel stochastic particle tracking model is developed to predict the particle settling out and deposition from a sediment-laden jet. Particle velocity fluctuations in the jet flow are modelled from a Lagrangian velocity autocorrelation function that incorporates the physical mechanism leading to a reduction of settling velocity. The model is first applied to study the settling velocity modulation in a homogeneous turbulence field. Consistent with basic experiments using grid-generated turbulence and computational fluid dynamics (CFD) calculations, the model predicts that the apparent settling velocity can be reduced by as much as 30 % of the stillwater settling velocity. Using analytical solution for the jet mean flow and semi-empirical RMS turbulent velocity fluctuation and dissipation rate profiles derived from CFD predictions, model predictions of the sediment deposition and cross-sectional concentration profiles of horizontal sediment-laden jets are in excellent agreement with data. Unlike CFD calculations of sediment fall out and deposition from a jet flow, the present method does not require any a priori adjustment of particle settling velocity. 相似文献
50.
Andy M. Reynolds Patrick Schultheiss Ken Cheng 《Behavioral ecology and sociobiology》2013,67(8):1219-1226
Honeybees (Apis mellifera) are regularly faced with the task of navigating back to their hives from remote food sources. They have evolved several methods to do this, including compass-directed “vector” flights and the use of landmarks. If these hive-centered mechanisms are disrupted, bees revert to searching for the hive, using an optimal Lévy flight searching strategy. The same strategy is adopted when a food source at a known location ceases to be available. Here, we show that the programming for this Lévy strategy does not need to be very sophisticated or clever on the bee’s part, as Lévy flight patterns can be derived from the Weber–Fechner law in a bee’s odometer. Odometry errors of a different kind occur in desert ants (Cataglyphis spp., Melophorus bagoti). The searching behaviors of these ants are very similar in overall structure to that of honeybees but do not display any Lévy flight characteristics. We suggest that errors in the estimation of distance can be implicitly involved in shaping the structure of systematic search behavior and should not be regarded as merely deficiencies in the odometer. 相似文献