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41.
/ The Florida Keys National Marine Sanctuary (FKNMS), created by Congress in 1990, addressed the issue of resource protection partly by proposing 26 "no-take" zones. These areas, discussed in the 1995 Draft Management Plan, disallowed all extractive activities, and four of the zones also prohibited diving and snorkeling. Furthermore, the Draft Management Plan considered recreational carrying capacity, proposing that use densities be studied and eventually limited in high-use and sensitive areas. Conducted with 62 commercial dive operators from the Florida Keys in 1995-96, this study uses geographic information systems (GIS) to determine the extent of FKNMS zone use by dive operators, assess the regional importance of FKNMS zones to operators, and compare management strategies by which to allow use while minimizing impacts to the coral reef resource. Dive operators took almost 70% of their total trips and 77% of their total divers to FKNMS zones in 1995. Although zone use is generally related to the proximity of dive locations, dive operators do rely disproportionately on single sites in certain regions. The resulting profiles demonstrate that management strategies need to consider disproportionate use, as well as the average number of users per trip, to effectively protect the region's environmental resources. In addition to implementing a carrying capacity plan, the FKNMS should consider a limited-entry system for dive operators.  相似文献   
42.
This paper deals with energy management in hybrid electric vehicles. Use of radial basis function neural network (RBFNN) for the problem of energy management gains importance in the present decade. Use of genetic algorithm (GA) and particle swarm optimization (PSO) as optimization algorithms for parameter estimation is also well known. However, none of the researchers in the area tried to use GA and PSO as training algorithms for the problem. Hence in this paper, we propose two novel methods, based on RBFNN. The difference between RBFNN-based approaches in the literature and those used in this paper is the use of GA and PSO (i.e. optimising algorithms) as training algorithm to train RBFNNs. Interestingly, it is seen that the proposed approaches of this paper outperform RBFNN-based approaches in the literature with traditional training.  相似文献   
43.
Significant accumulation of heavy metals in soils and flora exists around the abandoned Barbadalhos Pb mine in Central Portugal. Soil and plant samples [49 species] were collected from two line transects, LT 1 and LT 2, in the mineralized and non-mineralized area, respectively to gain a comprehensive picture of heavy metals in soils and flora to assess its potential for phytoremediation. Phytosociological inventories of the vegetation were made using the Braun-Blanquet cover-abundance scale. Metal concentrations in soil ranged from (in mg kg?1): 98–9330 [Pb], 110–517 [Zn], 7.1–50 [Co], 69–123 [Cr], 31–193 [Cu], 33 400–98 500 [Fe], 7.7–51 [Ni], 0.95–13 [Ag], 2.8–208 [As], and 71–2220 [Mn] along LT 1; and 24–93 [Pb], 30–162 [Zn], 3.7–34 [Co], 61–196 [Cr], 21–46 [Cu], 24 100–59 400 [Fe], 17–87 [Ni], 0.71–1.9 [Ag], 4.3–12 [As], and 44–1800 [Mn] along LT 2. Plant metal content ranged from (in mg kg?1): 1.11–548 [Pb], 7.06–1020 [Zn], 0.08–2.09 [Co], 0.09–2.03 [Cr], 2.63–38.5 [Cu], 10.4–4450 [Fe], 0.38–8.9 [Ni], and 0.03–1.9 [Ag] along LT 1; and 0.94–11.58 [Pb], 2.83–96.5 [Zn], 0.12–1.44 [Co], 0.21–1.49 [Cr], 1.61–22.7 [Cu], 4.6–2050 [Fe], 0.51–4.81 [Ni], and 0.02–0.31 [Ag] along LT 2. Plants with highest uptake of metals were: Cistus salvifolius (548 mg Pb kg?1), Digitalis purpurea (1017 mg Zn kg?1 and 4450 mg Fe kg?1). Mentha suavolens and Ruscus ulmifolius were seen to hyperaccumulate Ag (1.9 and 1 mg Ag kg?1, respectively). More metals and higher concentrations were traced in plants from LT 1, especially for Pb and Zn.  相似文献   
44.
Blends of poly-3-hydroxybutyrate with an elastomeric medium-chain-length poly-3-hydroxyalkanoate (MCL-PHA), containing 98 mol% 3-hydroxyoctanoate and 2 mol% 3-hydroxyhexanoate (referred to as PHO), were prepared by melt compounding. Coarsening of the droplet-matrix morphology of the blends was noted as the PHO content increased beyond 5 wt%; this was attributed to the significant viscosity mismatch between the components. Addition of PHO improved the thermal stability of the blends, reduced their crystallinity and resulted in shifts in their melting and crystallization temperatures. The blends had improved tensile strain at break. The unnotched impact strength showed a threefold increase at 30 wt% PHO content. Cross-linking of PHO using a peroxide initiator increased its viscosity, thus improving the morphology and mechanical properties of the blends.  相似文献   
45.
Atenolol is a β-blocker drug and an identified emerging pollutant. Advanced oxidation processes (AOPs) utilise the reaction of a highly oxidising species (hydroxyl radicals, ?OH) for the mineralisation of emerging pollutants since conventional treatment methodologies generally fail to degrade these compounds. In the present work, degradation of atenolol was carried out using ultrasound with frequencies ranging from 200 kHz to 1 MHz as a source of hydroxyl radical. The degradation was monitored by HPLC, total organic carbon (TOC) and chemical oxygen demand (COD) reduction and ion chromatography (IC). Nearly 90 % of degradation of atenolol was observed with ultrasound having 350 kHz. Both frequency and power of ultrasound affect the efficiency of degradation. Nearly 100 % degradation was obtained at a pH of 4. Presence of various additives such as sodium dodecyl sulphate, chloride, sulphate, nitrate, phosphate and bicarbonate was found to reduce the efficiency of degradation. Although nearly 100 % degradation of atenolol was observed under various experimental conditions, only about 62 % mineralisation (from TOC and COD measurements) was obtained. Nearly eight intermediate products were identified using high-resolution mass spectrometry (LC-Q-TOF). These products were understood as the results of hydroxyl radical addition to atenolol. The degradation studies were also carried out in river water which also showed a similar degradation profile. A mechanism of degradation and mineralisation is presented.  相似文献   
46.
SoilTrEC: a global initiative on critical zone research and integration   总被引:1,自引:0,他引:1  
Soil is a complex natural resource that is considered non-renewable in policy frameworks, and it plays a key role in maintaining a variety of ecosystem services (ES) and life-sustaining material cycles within the Earth's Critical Zone (CZ). However, currently, the ability of soil to deliver these services is being drastically reduced in many locations, and global loss of soil ecosystem services is estimated to increase each year as a result of many different threats, such as erosion and soil carbon loss. The European Union Thematic Strategy for Soil Protection alerts policy makers of the need to protect soil and proposes measures to mitigate soil degradation. In this context, the European Commission-funded research project on Soil Transformations in European Catchments (SoilTrEC) aims to quantify the processes that deliver soil ecosystem services in the Earth's Critical Zone and to quantify the impacts of environmental change on key soil functions. This is achieved by integrating the research results into decision-support tools and applying methods of economic valuation to soil ecosystem services. In this paper, we provide an overview of the SoilTrEC project, its organization, partnerships and implementation.  相似文献   
47.
This paper reports the bioefficacy of selected insecticides against thrips and their pre-harvest intervals (PHI) in onion pertaining to their recommended application rates and maximum residue limits. Profenophos, methomyl and imidacloprid showed comparatively higher bioefficacy against thrips. GC-MS and LC-MS/MS-based residue analysis methods in onion bulbs and composite matrix of bulbs+leaves were thoroughly validated. The residue data for bulb+leaves was assessed with reference to the EU-MRLs applicable for spring onion. Dimethoate was the most stable chemical with PHI of 52.5 days, followed by monocrotophos (24 days) and carbofuran (20.5 days). The PHIs of profenophos, chlorpyrifos, methomyl and cypermethrin were similar and within the range of 10–13 days. Imidacloprid and λ-cyhalothrin had similar PHI of 4.5 days. Spinosad was the fastest-degrading chemical with PHI of 2 days. The combined bioefficacy and residue dynamics information will support label-claim of these insecticides for the management of thrips in onion, help in scheduling their applications in pest management program as per relative PHIs and minimize the residue accumulations at harvest. The dietary exposure was less than the maximum permissible intake for most of the insecticides on all sampling days except for dimethoate and monocrotophos.  相似文献   
48.
Pesticide spraying operation is associated with the increased risk of adverse health effects among sprayers who do not follow safe farm work practices. A study was conducted among pesticide sprayers in North India to evaluate the clinical and subclinical variations in their vital health parameters before and after the pesticide spraying season. Blood cholinesterase levels, pulmonary function test, nerve conduction velocity and self-reported symptoms were studied among 18 eligible and consenting male sprayers. Mean acetylcholinesterase activity was reduced by 55 % in the post-exposure assessment (P?<?0.001) as compared to pre-exposure levels. Mean forced expiratory volume in 1 s was 20 % lower in the post-exposure assessment as compared to the pre-exposure level (P?<?0.05). No significant change was observed in the motor and sensory nerve conduction velocity in the median nerve of sprayers before and after the spraying activity. Also, no significant variation was observed with respect to self-reported symptoms except weakness in arms and legs (P?<?0.05). The significant decline in lung function and acetylcholinesterase level after pesticide exposure reflects the strongly negative effect of exposure to pesticides during spraying activity. More longitudinal studies among pesticide sprayers must be undertaken to further substantiate the cause–effect relationship between pesticide exposure and its subclinical effects. There is a strong necessity to minimise the exposure through the use of personal protective equipment in pesticide sprayers.  相似文献   
49.
Every year, during the pre-monsoon period (March–May), a pronounced increase in aerosol optical depth (AOD) is observed over the eastern Arabian Sea, which is attributed to the transport of continental aerosols. This paper presents the altitude distribution of tropospheric aerosols, characteristics of elevated aerosol layers and aerosol radiative heating of the atmosphere during the pre-monsoon season over Trivandrum (8.5°N, 77°E), a station located at the southwest coast of Indian peninsula which is covered by the eastern Arabian Sea plume. Altitude profiles of aerosol backscatter coefficient (βa) and linear depolarization ratio (LDR) reveal two distinct aerosol layers persisting between 0–2 km and 2–4 km. The layer at 2–4 km, which contributes about 25% of the AOD during polluted conditions, contains significant amount of non-spherical aerosols. This layer is prominent only when the advection of dry airmass occurs from the northern parts of the Indian subcontinent and northern Arabian Sea. Role of long-range transport in the development of this aerosol layer is further confirmed using latitude–altitude cross-section of βa observed by CALIPSO. Aerosol content in the layer below 2 km is large when advection of air occurs from the north and east Arabian Sea and is significantly small when it occurs from the southwest Arabian Sea or Indian Ocean. During the highly polluted conditions, aerosols tend to increase the diurnal mean atmospheric radiative heating rate by ~0.8 K day?1 at 500 m and 0.3 K day?1 at 3 km, which are about 80% and 30% of the respective radiative heating in the aerosol-free atmosphere.  相似文献   
50.
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