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81.
The important role that non-motorised transport plays in urban sustainability is discussed with particular reference to the developing world and to the links between environmental and poverty issues. The significance of non-motorised transport in terms of reduced pollution, income maintenance for the poor and providing transport for vulnerable groups is stressed and placed within the general context of sustainable development. More specifically, evidence is presented for rickshaws in Calcutta, which demonstrates the vital role that non-motorised transport must play if sustainable development objectives are to be met. This evidence indicates that if rickshaws were to disappear from Calcutta's streets there would not only be significant increases in air pollution but also a substantial increase in the numbers of people living in poverty. 相似文献
82.
Massimo Barbeni Edmondo Pramauro Ezio Pelizzetti Enrico Borgarello Nick Serpone 《Chemosphere》1985,14(2):195-208
The heterogeneous photocatalytic degradation of pentachlorophenol (PCP) in aqueous solutions containing a suspension of TiO2 leads to the quantitative formation of CO2 and HC1. The photodegradation has also been studied in other semiconductor dispersions such as ZnO, CdS, WO3, and SnO2. TiO2 appears the most efficient. Oxygen and water are essential ingredients in the complete mineralization of this pollutant found near pulp and paper industries. Experiments with sunlight show a promising route for the water treatment processes; the half life of PCP (initial concentration 4.5 × 10?5M) is about 8 minutes, in the presence of 2 g/l of TiO2. 相似文献
83.
84.
Genetic structure and phylogeography of the lined shore crab, Pachygrapsus crassipes, along the northeastern and western Pacific coasts 总被引:1,自引:0,他引:1
Marine invertebrates with high larval dispersal capacity typically exhibit low degrees of population differentiation, which reflects both contemporary and historical processes. We sampled 346 individuals from seven populations of the lined shore crab, Pachygrapsus crassipes Randall, along the northeastern Pacific Coast and Korea during summer 2003. DNA sequence analysis of 613 bp of the mitochondrial COI gene showed that overall gene diversity (h) was high (0.92±0.01), whereas overall nucleotide diversity (π) was low (0.009±0.005). A total of 154 mtDNA haplotypes were identified; however, 114 were present in only one individual. Analysis of molecular variance revealed significant genetic structuring at Point Conception, CA, USA, that is likely due to the oceanographic circulation patterns, which result in asymmetrical migration of haplotypes. However, genetic variation among eastern Pacific populations was generally low, probably because of high contemporary gene flow and recent common ancestry of haplotypes. Mismatch analysis and nested clade analysis suggested that the population history of this region is characterized by two contiguous northwards range expansions, which are congruent with Late Pleistocene glacial cycles. Highly significant genetic differentiation was detected between eastern Pacific populations and Korea, indicating transpacific gene flow is restricted. Time of divergence between the two transpacific lineages was estimated between 0.8 and 1.2 Myrs ago. The small, recently founded population of P. crassipes at Bamfield, BC, Canada, did not appear to have undergone a founder effect. 相似文献
85.
The morphology and behavior of dimorphic males in Perdita portalis (Hymenoptera : Andrenidae) 总被引:4,自引:0,他引:4
Bryan N. Danforth 《Behavioral ecology and sociobiology》1991,29(4):235-247
Summary In Perdita portalis, a ground nesting, communal bee, males are clearly dimorphic. The two male morphs are easily distinguished based on head size and shape into (1) a flight-capable, small-headed (SH) morph that resembles the males of other closely related species and (2) a flightless, large-headed (LH) morph that possesses numerous derived traits, such as reduced compound eyes, enlarged facial foveae and fully atrophied indirect flight muscles. The SH morph occurs exclusively on flowers while the LH morph is found only in nests with females. While on flowers, SH males are aggressive, fighting with conspecific males and heterospecific male and female bees, and they mate frequently with foraging females. Using artificial observation nests placed in the field, I observed the behavior of females and LH males within their subterranean nests. LH males are aggressive fighters; males attacked each other with mandibles agape, and male-male fights always ended in the death of one male. LH males are highly attentive to the reproductive behavior of females; they spend increasing amounts of time near open cells during cell provisioning, and mating only takes place immediately prior to oviposition when females are forming the accumulated pollen and nectar into a ball. Based on larvae reared to adulthood in the laboratory, the two male morphs occur in equal proportions. The behavior of males in closely related species, especially P. texana, and the origin and maintenance of male dimorphism are discussed. 相似文献
86.
Bernd Markert Rainer Steinbeck Karl-Josef Nick Karl-Georg Bernhardt 《Environmental geochemistry and health》1990,12(3):239-244
The concentrations of Ag, Al, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, K, La, Li, Mg, Mn, Mo, Na, Ni, P, Pb, Rb, Sr, Ti, V and Zn were determined by AES/ICP inMolinia caerulea andEriophorum vaginatum grown in the Leegmoor, which is in reinstatement. In the soil substrate analytical detection limits were obtained for Ag, Co, Li, Mo and Rb and additionally for Al, Be, Cd, Cr, La, Li, Ni, Pb, Ti and V in plants. Compared with mineral soils, the concentration of elements in peat is low. The elements K and P were enriched byMolinia caerulea andEriophorum vaginatum, and in addition Mn and Zn byEriophorum vaginatum. Altogether the ability of accumulation essential elements seem to be more efficient byEriophorum vaginatumthan byMolinia caerulea, which can be an ecophysiological advantage on peats, whereMolinia caerulea is normally not distributed. 相似文献
87.
Snapping turtles are capable of storing extremely high concentration of organochlorine compounds in their fat without any apparent detrimental effect. This tolerance, to high bioconcentration, permits a wide gradation between the extremes in pollution levels and facilitates the detection of extremely toxic substances present in trace amounts. Consequently snapping turtles provide an excellent biological screen for these compounds. 相似文献
88.
Christopher P. Loughner Melanie B. Follette-Cook Bryan N. Duncan Jennifer Hains Kenneth E. Pickering Justin Moy 《Journal of the Air & Waste Management Association (1995)》2020,70(2):193-205
ABSTRACTUsing the Community Multiscale Air Quality (CMAQ) model and the Benefits Mapping and Analysis Program – Community Edition (BenMAP-CE) tool, we estimate the benefits of anthropogenic emission reductions between 2002 and 2011 in the Eastern United States (US) with respect to surface ozone concentrations and ozone-related health and economic impacts, during a month of extreme heat, July 2011. Based on CMAQ simulations using emissions appropriate for 2002 and 2011, we estimate that emission reductions since 2002 likely prevented 10– 15 ozone exceedance days (using the 2011 maximum 8-hr average ozone standard of 75 ppbv) throughout the Ohio River Valley and 5– 10 ozone exceedance days throughout the Washington, DC – Baltimore, MD metropolitan area during this extremely hot month. CMAQ results were fed into the BenMAP-CE tool to determine the health and health-related economic benefits of anthropogenic emission reductions between 2002 and 2011. We estimate that the concomitant health benefits from the ozone reductions were significant for this anomalous month: 160–800 mortalities (95% confidence interval (CI): 70–1,010) were avoided in July 2011 in the Eastern U.S, saving an estimated $1.3–$6.6 billion (CI: $174 million–$15.5 billion). Additionally, we estimate that emission reductions resulted in 950 (CI: 90–2,350) less hospital admissions from respiratory symptoms, 370 (CI: 180–580) less hospital admissions for pneumonia, 570 (CI: 0–1650) less Emergency Room (ER) visits from asthma symptoms, 922,020 (CI: 469,960–1,370,050) less minor restricted activity days (MRADs), and 430,240 (CI: ?280,350–963,190) less symptoms of asthma exacerbation during July 2011.Implications: We estimate the benefits of air pollution emission reductions on surface ozone concentrations and ozone-related impacts on human health and the economy between 2002 and 2011 during an extremely hot month, July 2011, in the eastern United States (US) using the CMAQ and BenMAP-CE models. Results suggest that, during July 2011, emission reductions prevented 10-15 ozone exceedance days in the Ohio River Valley and 5-10 ozone exceedance days in the Mid Atlantic; saved 160-800 lives in the Eastern US, saving $1.3 - $6.5 billion; and resulted in 950 less hospital admissions for respiratory symptoms, 370 less hospital admissions for pneumonia, 570 less Emergency Room visits for asthma symptoms, 922,020 less minor restricted activity days, and 430,240 less symptoms of asthma exacerbation. 相似文献
89.
We investigated the relative roles of natural factors and shoreline harvest leading to recent declines of the black leather chiton (Katharina tunicata) on the outer Kenai Peninsula, Alaska (U.S.A.). This intertidal mollusk is a strongly interacting grazer and a culturally important subsistence fishery for Sugpiaq (Chugach Alutiiq) natives. We took multiple approaches to determine causes of decline. Field surveys examined the significant predictors of Katharina density and biomass across 11 sites varying in harvest pressure, and an integrated analysis of archaeological faunal remains, historical records, traditional ecological knowledge, and contemporary subsistence invertebrate landings examined changes in subsistence practices through time. Strong evidence suggests that current spatial variation in Katharina density and biomass is driven by both human exploitation and sea otter (Enhydra lutris) predation. Traditional knowledge, calibrated by subsistence harvest data, further revealed that several benthic marine invertebrates (sea urchin, crab, clams, and cockles) have declined serially beginning in the 1960s, with reduced densities and sizes of Katharina being the most recent. The timing of these declines was coincident with changes in human behavior (from semi-nomadic to increasingly permanent settlement patterns, improved extractive technologies, regional commercial crustacean exploitation, the erosion of culturally based season and size restrictions) and with the reestablishment of sea otters. We propose that a spatial concentration in shoreline collection pressure through time, increased harvest efficiency, and the serial depletion of alternative marine invertebrate prey have led to intensified per capita predator impacts on Katharina and thus its recent localized decline. 相似文献
90.
Jane Bryan Phil Shearman Julian Ash J.B. Kirkpatrick 《Journal of environmental management》2010,91(4):995-1001
Reduction of carbon emissions from tropical deforestation and forest degradation is being considered a cost-effective way of mitigating the impacts of global warming. If such reductions are to be implemented, accurate and repeatable measurements of forest cover change and biomass will be required. In Papua New Guinea (PNG), which has one of the world's largest remaining areas of tropical forest, we used the best available data to estimate rainforest carbon stocks, and emissions from deforestation and degradation. We collated all available PNG field measurements which could be used to estimate carbon stocks in logged and unlogged forest. We extrapolated these plot-level estimates across the forested landscape using high-resolution forest mapping. We found the best estimate of forest carbon stocks contained in logged and unlogged forest in 2002 to be 4770 Mt (±13%). Our best estimate of gross forest carbon released through deforestation and degradation between 1972 and 2002 was 1178 Mt (±18%). By applying a long-term forest change model, we estimated that the carbon loss resulting from deforestation and degradation in 2001 was 53 Mt (±18%), rising from 24 Mt (±15%) in 1972. Forty-one percent of 2001 emissions resulted from logging, rising from 21% in 1972. Reducing emissions from logging is therefore a priority for PNG. The large uncertainty in our estimates of carbon stocks and fluxes is primarily due to the dearth of field measurements in both logged and unlogged forest, and the lack of PNG logging damage studies. Research priorities for PNG to increase the accuracy of forest carbon stock assessments are the collection of field measurements in unlogged forest and more spatially explicit logging damage studies. 相似文献