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181.
Rodolfo Sousa Marcello Veiga Dirk Van Zyl Kevin Telmer Sam Spiegel Jeff Selder 《Journal of Cleaner Production》2011,19(6-7):742-750
In Brazil, artisanal and small-scale gold mining (ASGM) produces in the range of 6 tonnes of gold (Au) per annum, and employs approximately 200,000 people. Most of this mining activity is in the Amazon region, where miners have been extracting gold for more than 40 years. In the Tapajos River Basin, assessments indicate that around 99% of miners operate without the environmental and mining permits required by law. This is a result of a combination of unrealistic or lack of proper policies and regulations, lack of political will, lack of infra-structure to enforce the existing regulations and lack of incentives to miners to comply with legal requirements.In this article, we analyze a group of 20 laws, decrees and resolutions in Brazil, focusing on how idiosyncrasies in these regulations reveal gaps between policy and reality in ASGM areas. Artisanal miners operate in vast and remote areas and the government lacks the resources (personnel, vehicles, information and materials) to enforce the laws. Our analysis emphasizes the need for creating new government commitments and identifying priority areas where government agents can focus their efforts.There is no single solution for the environmental, health, technical and socio-economic problems associated with ASGM. However, a realistic approach should consider improving the level of education of miners, creating government programs to provide technical assistance in the field, simplifying administrative procedures and ensuring adequate measures for enforcement. 相似文献
182.
Stefan Aerts Dirk Lips Stuart Spencer Eddy Decuypere Johan De Tavernier 《Journal of Agricultural and Environmental Ethics》2006,19(1):67-76
When making an assessment of animal welfare, it is important to take environmental (housing) or animal-based parameters into
account. An alternative approach is to focus on the behavior and appearance of the animal, without making actual measurements
or quantifying this. None of these tell the whole story. In this paper, we suggest that it is possible to find common ground
between these (seemingly) diametrically opposed positions and argue that this may be the way to deal with the complexity of
animal welfare. The model will have to be acceptable for the different parties that will be affected by it and real benefits
for the animal should result from it. This will be the basis of a practical ethical approach. All this can be condensed into
a model that essentially is made up out of three basic elements: the classical welfare analysis with an existing welfare assessment
tool, an assessment of the stockholder, and an implementation of the Free Choice Profiling technique. This new framework does
not pretend to be a different or better animal welfare matrix; it is intended to integrate existing knowledge and to provide
a practical tool to improve animal welfare. It identifies whether there are welfare problems on a farm, if present whether
these problems are caused by the housing system or the stockholder, and what can be done to improve the situation. 相似文献
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Stephanie Hans Sandra Fehsenfeld Jason R. Treberg Dirk Weihrauch 《Marine Biology》2014,161(5):1179-1193
Homeostatic regulation allows organisms to secure basic physiological processes in a varying environment. To counteract fluctuations in ambient carbonate system speciation due to elevated seawater pCO2 (hypercapnia), many aquatic crustaceans excrete/accumulate acid–base equivalents through their gills; however, not much is known about the role of ammonia in this response. The present study investigated the effects of hypercapnia on acid–base and ammonia regulation in the Dungeness crab, Metacarcinus magister on the whole animal and isolated gill levels. Hemolymph pCO2 and [HCO3 ?] increased in M. magister acclimated to elevated pCO2 (330 Pa), while pH remained stable. Additionally, hemolymph [Na+], [Ca2+], and [SO4 2?] were significantly increased. When challenged with varying pH during gill perfusion, the pH of the artificial hemolymph remained relatively unchanged. Overall, ammonia production and excretion, as well as oxygen consumption, were reduced in crabs acclimated to elevated pCO2, demonstrating that either (amino acid) oxidation is reduced in response to this particular stress, or nitrogenous wastes are excreted in an alternative form. 相似文献
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Selenium and nano-selenium in plant nutrition 总被引:1,自引:0,他引:1
Hassan El-Ramady Neama Abdalla Hussein S. Taha Tarek Alshaal Ahmed El-Henawy Salah E.-D. A. Faizy Mohamed S. Shams Sarwat M. Youssef Tarek Shalaby Yousry Bayoumi Nevien Elhawat Said Shehata Attila Sztrik József Prokisch Miklós Fári Éva Domokos-Szabolcsy Elizabeth A. Pilon-Smits Dirk Selmar Silvia Haneklaus Ewald Schnug 《Environmental Chemistry Letters》2016,14(1):123-147
Selenium (Se) is a naturally occurring metalloid element which occurs nearly in all environments. Se is considered as a finite and non-renewable resource on the Earth. The common sources of Se in earth’s crust occur in association with sulfide minerals such as metal selenide, whereas it is rarely found in elemental form (Se0). While there is no evidence of Se need for higher plants, several reports show that when Se added at low concentrations, Se exerts beneficial effects on plant growth. Se may act as quasi-essential micronutrient through altering different physiological and biochemical traits. Thus, plants vary considerably in their physiological and biochemical response to Se. This review focusses on the physiological importance of Se forms as well as different Se fertilizers for higher plants, especially plant growth, uptake, transport, and metabolism. 相似文献
188.
Susanne Foitzik Ilka Maria Kureck Markus Hannes Rüger Dirk Metzler 《Behavioral ecology and sociobiology》2010,64(10):1641-1654
The ant Hypoponera opacior exhibits alternative reproductive morphs of males and females associated with distinct sexual behaviours. Our long-term study
reports strong seasonality in sexual production with a mating season in early and one in late summer. Winged (alate) reproductives
emerge in June, swarm during the monsoon season and establish new colonies independently. In contrast, wingless worker-like
(ergatoid) reproductives that appear in late August mate within their natal or adjacent nests and either do not disperse or
establish new nests close by. These divergent dispersal patterns allowed us to analyse the impact of local factors on investment
strategies by comparing sex allocation between and within the two reproductive events. The optimal sex ratio for ergatoid
reproductives should be influenced both by competition for matings between brothers (local mate competition) and rivalry among
young locally dispersing queens for workers, nest sites or food (local resource competition). The greater importance of local
resource competition was demonstrated both by a male-biased sex ratio for wingless sexuals and a stronger increase in the
number of males with total sexual production than for the number of queens. Microsatellite analysis revealed that inter-nest
variation in relatedness asymmetry cannot explain split sex ratios in the August generation. Instead, nests with related ergatoid
males raised a male-biased sex ratio contrary to the expectations under local mate competition. In conclusion, male bias in
wingless H. opacior indicates that local mate competition is less strong than local resource competition among ergatoid queens over the help
of workers during nest foundation. 相似文献
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