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121.
122.
Derek Lovejoy 《Natural resources forum》1992,16(2):102-110
More than 2000 million people, mostly in developing countries, live in rural areas without access to grid connected power. Conventional approaches to supplying power, whether through extension of existing grids or through stand-alone 'minigrids' based on diesel generator sets, or even on renewable energy minigrids, require large investments which are unlikely to receive priority in competition with more economically and politically attractive investments in urban areas. Domestic PV lighting and broadcast reception kits (DLKs), comprising, typically, a 30–60 W panel, an automotive battery, a charge indicator, and dc fluorescent lamps can be furnished and installed for about $500. DLKs are now used in the Dominican Republic, Kenya, Sri Lanka and many other countries. DLKs provide a minimum essential service with low overheads. Given the necessary credit facilities, they can give better service at comparable costs in comparison with kerosene lamps and dry cell powered radios. They also permit a substantial degree of local manufacture, thus saving on foreign exchange. This movement is starting in many countries on a purely commercial basis. The process could be greatly accelerated if 'seed money' in the form of revolving funds could be made available. 相似文献
123.
Dromaeosaurids from the Maastrichtian of North America have a poor fossil record and are known largely from isolated teeth, which have typically been referred to taxa based on more complete material from earlier Campanian strata. An almost complete maxilla with well-preserved dentition and an associated dentary from the Hell Creek Formation of Montana are used to establish a new dromaeosaurid taxon in the latest Maastrichtian, immediately prior to the end-Cretaceous extinction event. Acheroraptor temertyorum gen. et sp. nov. is differentiated from other dromaeosaurids on the basis of a hypertrophied postantral wall that projects posteriorly into the antorbital fenestra, a maxillary fenestra positioned low in the antorbital fossa and directly posterior to the promaxillary fenestra, and distinctive dentition with marked apicobasal ridges. The new material allows a dromaeosaurid from the Maastrichtian of North America to be placed within a phylogenetic framework for the first time. Phylogenetic analysis suggests Acheroraptor is a velociraptorine that is more closely related to Asian dromaeosaurids, including Tsaagan and Velociraptor, than it is to Dromaeosaurus, Saurornitholestes, or any other taxon from North America. As part of the Lancian Tyrannosaurus–Triceratops fauna, A. temertyorum is the latest occurring dromaeosaurid. Its relationships and occurrence suggest a complex historical biogeographic scenario that involved multiple, bi-directional faunal interchanges between Asia and North America during the Late Cretaceous. 相似文献
124.
125.
Derek Winstanley Stanley A. Changnon 《Journal of the American Water Resources Association》1999,35(6):1421-1427
ABSTRACT: An analysis of historical relationships between seasonal weather conditions and water resource conditions in Illinois provides insights to the challenges of projecting such relationships under conditions of climate change. In Illinois for 1901–1997 there were major temporal shifts in types of seasonal conditions that have positive and negative effects on surface water and ground water supplies and their quality. Major seasonal effects came in the spring and summer seasons and when either wet-and-warm or dry-and-warm weather conditions prevailed in either season. Sixty percent of the summer seasons creating negative impacts occurred during only 40 years: 1911–1940 and 1951–1960. Seasons creating impacts relate well to the frequency of cyclone passages and to the incidence of El Niño or La Niña conditions. This reveals that future climate fluctuations that shift the frequency of cyclones and/or ENSO events will have profound effects on Midwestern seasonal conditions that affect water resources. Projecting future effects of climate change on water resources will need to consider how shifts in water use and water management technologies act to re-define the seasonal weather conditions that are critical. 相似文献
126.
An Empirical Evaluation of Private Landowner Participation in Voluntary Forest Conservation Programs
The use of voluntary programs targeting resource conservation on private land has become increasingly prevalent in environmental
policy. Voluntary programs potentially offer significant benefits over regulatory and market-based approaches. This article
examines the factors affecting landowner participation in voluntary forest conservation programs using a combination of parcel-level
GIS and remotely sensed data and semi-structured interviews of landowners in Monroe County, Indiana. A logistic regression
model is applied to determine the probability of participation based on landowner education, membership in other non-forest
voluntary programs, dominant land use activity, parcel size, distance from urban center, land resource portfolios, and forest
cover. Both land use activity and the spatial configuration of a landholder’s resource portfolio are found to be statistically
significant with important implications for the design and implementation of voluntary programs.
相似文献
Derek KauneckisEmail: |
127.
Hg and legacy POPs were analysed in muscle tissue of a landlocked Arctic char (Salvelinus alpinus) population from a small lake in southwest Greenland. Hg concentrations were available for six years and OC concentrations for five years during the period 1994 to 2008. For two years, stable isotope values of nitrogen (δ(15)N) were analysed in muscle tissue in order to infer trophic effects. Hg, Σ10-PCB, ΣDDT and trans-nonachlor concentrations (OC on wet weight basis) showed an increase with increasing fish length, which had to be accounted for when assessing temporal trends. δ(15)N values had a narrow range, and there was no indication of increasing δ(15)N values with char length confirming the sampled char did not vary in trophic morphs as often seen in Arctic lakes. Length-adjusted Hg concentrations showed a significantly increasing trend during the period 1994 to 2008, while Σ10-PCB, ΣDDT, ΣHCH and trans-nonachlor showed a significantly decreasing trend when expressed on wet weight, and decreasing but not significantly when expressed on lipid weight. The reason for this was that the lipid content of muscle showed a significantly decreasing trend with time. The sum of mean monthly air temperature during May to August measured at a nearby meteorological station showed an increasing trend during the study period, and changing temperature conditions probably influenced the temporal trend of especially Hg concentrations and the lipid content. 相似文献
128.
Innovative work behavior and sex‐based stereotypes: Examining sex differences in perceptions and evaluations of innovative work behavior 下载免费PDF全文
Building on role congruity theory, we predict that innovative work behaviors are stereotypically ascribed to men more than to women. Because of this bias, women who innovate may not receive better performance evaluations than those who do not innovate, whereas engaging in innovative work behaviors is beneficial for men. These predictions were supported across 3 complementary field and experimental studies. The results of an experiment (Study 1; N = 407) revealed that innovative work behaviors are stereotypically associated with men more than women. In Studies 2 and 3, using multisource employee evaluation data (N = 153) and by experimentally manipulating innovative work behaviors (N = 232), respectively, we found that favorable performance evaluations were associated with innovative work behaviors for men but not for women. These studies highlight a previously unidentified form of sex bias and are particularly important for those wishing to increase innovative behaviors in the workplace: We need to address this phenomenon of “think innovation‐think male.” 相似文献
129.
Peter I. Macreadie Paul H. York Craig D. H. Sherman Michael J. Keough D. Jeff Ross Aurora M. Ricart Timothy M. Smith 《Marine Biology》2014,161(12):2939-2944
Seagrass meadows are among the most efficient and long-term carbon sinks on earth, but disturbances could threaten this capacity, so understanding the impacts of disturbance on carbon stored within seagrass meadows—‘blue carbon’—is of prime importance. To date, there have been no published studies on the impacts of seagrass loss on ‘blue carbon’ stocks. We experimentally created several kinds of small-scale disturbances, representative of common grazer and boating impacts, within seagrass (Zostera nigracaulis) meadows in Port Phillip Bay (Australia) and measured the impacts on sediment organic carbon stocks (‘C org’, and other geochemical variables—%N, δ13C, δ15N). Disturbance had no detectable effect on C org levels within seagrass sediments, even for high-intensity disturbance treatments, which remained bare (i.e. no seagrass recovery) for 2 years after the disturbance. These findings challenge the widely held assumption that disturbance and concomitant loss of seagrass habitat cause release of carbon, at least for small-scale disturbances. We suggest that larger (e.g. meadow scale) disturbances may be required to trigger losses of ‘blue carbon’ from seagrass meadows. 相似文献
130.
Changing the Course of Rivers in an Asian City: Linking Landscapes to Human Benefits through Iterative Modeling and Design 下载免费PDF全文
Derek Vollmer Diogo Costa Ervine Shengwei Lin Yazid Ninsalam Kashif Shaad Michaela F. Prescott Senthil Gurusamy Federica Remondi Rita Padawangi Paolo Burlando Christophe Girot Adrienne Grêt‐Regamey Joerg Rekittke 《Journal of the American Water Resources Association》2015,51(3):672-688
Concerns over water scarcity, climate change, and environmental health risks have prompted some Asian cities to invest in river rehabilitation, but deciding on the end goals of rehabilitation is a complex undertaking. We propose a multidisciplinary framework linking riparian landscape change to human well‐being, providing information relevant to decision makers, in a format that facilitates stakeholder involvement. We illustrate this through a case study of the densely settled, environmentally degraded, and flood prone Ciliwung River flowing through metropolitan Jakarta, Indonesia. Our methodology attempts to respond to this complexity through an iterative approach, strongly based on conceptualization and mathematical modeling. Nested hydrologic, hydrodynamic, and water quality models provide outputs at catchment‐, corridor‐, and localized site‐scales. Advanced 3‐D landscape modeling is used for procedural design and precise visualization of proposed changes and their impacts, as predicted by the mathematical models. Finally, participatory planning and design methods allow us to obtain critical stakeholder feedback in shaping a socially acceptable approach. Our framework aims at demonstrating that a change in paradigm in river rehabilitation is possible, and providing future scenarios that balance concerns over flooding, water quality, and ecology, with the realities of a rapidly growing megacity. 相似文献