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151.
/ The Itapiranga Sustainable Logging Plan provides an example of how Brazil's licensing system functions for logging companies in the state of Amazonas. Two questions need to be dealt with: "How sustainable can logging in the Amazon be?" and "What and how effective are existing legal mechanisms to deal with logging projects?" The environmental impact assessment (EIA) and environmental impact statement (EIS, known as the RIMA in Brazil), present relatively detailed accounts of biodiversity and the need to adopt conservation strategies to protect it. However, social and health impacts are only superficially addressed. The economic sustainability of the operation over multiple cycles is not demonstrated. The multidisciplinary teams responsible for the EIA and EIS (RIMA) reports are hired by the project proponent, an arrangement inherently carrying the risk of biasing the result. Logging reduces biodiversity, releases greenhouse gases and inflicts social and health costs. These impacts reduce the ability of Amazonian forests to provide environmental services and to supply food and livelihood security to local populations. The reports inflate positive effects such as employment: the estimated number of jobs was cut by more than half in a revision made after the EIA and EIS (RIMA) had been approved. Not only do the reports need to be more realistic in assessing both positive and negative consequences of proposed projects, but better means are needed to ensure that promised mitigatory measures are enforced in practice. Many of the lessons that can be drawn from the Itapiranga Plan are not unique to logging projects and apply to licensing of development activites generally in Brazil and elsewhere.  相似文献   
152.
Sicyos polyacanthus is one of the most important weed in sugarcane crops of Tucumán (Argentina). The objective of this work was to establish strategies that would decrease the weed incidence in the crop to a minimum level. The study was carried out during 1998--2003 at five localities of sugarcane production of Tucumán (Argentina). The plots were 20 m long (192 m2) with 6 furrows and each plot was replicated five times. Treatments were: (i) Mechanical-chemical cultivation without fire; (ii) Mechanical-chemical culltivation with fire; (iii) Mechanical cultivation with handle pulled and with fire; (iv) Mechanical cultivation with handle pulled without fire; (v) Mechanical and chemical variants with fertilization and without fertilization; (vi) Mechanical and chemical variants with watering and without watering; (vii) Fallow and rotation, at the sugarcane crop renovation; (viii) Mechanical and chemical variants for plant cane and ratoon cane; and (ix) Mulching of harvest rests. The results suggest that besides the use of preemergent herbicides, fire marks the entry point of control, influencing fluxes and seed viability. It appears that fallow, mulching, and rotation of crops is fundamental for eliminating seeds that live short time in the soil and increase the mortality rate of species.  相似文献   
153.
A number of models have been proposed to calculate overpressure and impulse from accidental industrial explosions. When the blast is produced by explosives, pyrotechnics or unstable substances, the TNT equivalent model is widely used. From the curves given by this model, data are fitted to obtain equations showing the relationship between overpressure, impulse and distance. These equations, referred to here as characteristic curves, can be fitted by means of power equations, which depend on the TNT equivalent mass. Characteristic curves allow determination of overpressure and impulse at each distance.  相似文献   
154.
The Amazonian forest is, due to its great size, carbon storage capacity and present-day variability in carbon uptake and release, an important component of the global carbon cycle. Paleo-environmental reconstruction is difficult for Amazonia due to the scarcity of primary palynological data and the mis-interpretation of some secondary data. Studies of lacustrine sediment records have shown that Amazonia has known periods in which the climate was drier than it is today. However, not all geomorphological features such as dunes, and slope erosion, which are thought to indicate rainforest regression, date from the time of the Late Glacial Maximum (LGM) and these features do not necessarily correspond to episodes of forest regression. There is also uncertainty concerning LGM carbon storage due to rainforest soils and biomass estimates. Soil carbon content may decrease moderately during the LGM, whereas rainforest biomass may change considerably in response to changes in the global environment. Biomass per unit area in Amazonia has probably been reduced by the cumulative effects of low CO2 concentration, a drier climate and lower temperatures. As few paleo-vegetation data are available, there is considerable uncertainty concerning the amount of carbon stored in Amazonia during the LGM, which may have corresponded to 44-94% of the carbon currently stored in biomass and soils.  相似文献   
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Leadership is considered an essential element in guaranteeing the safe running of organizations. The purpose of the present study is to find out how leader behaviours influence employees’ safety behaviours (perceived safety behaviours) in the nuclear field. In an attempt to answer this question, the authors of this research have considered the way this influence is exercised, taking into consideration some important factors like safety culture and safety climate. To achieve this, the empowerment leadership model, based on a behavioural approach to leadership, was used. The sample was made up of 566 employees from a Spanish nuclear power plant. The results indicated that when safety culture was strong, leader behaviour generated a higher safety climate among the members, which predicted their perceived safety behaviours. Support was found for a structural model linking leadership and safety behaviour to safety culture and safety climate. The implications of these findings for the theory of safety and the way they can be put into practice are outlined.  相似文献   
159.
A wet air oxidation (WAO) process was applied to four selected pharmaceuticals (metoprolol, naproxen, amoxicillin, and phenacetin) individually dissolved in ultra-pure water, varying the temperature and oxygen pressure. Due to the moderate (amoxicillin) or low (metoprolol, naproxen, and phenacetin) efficiency found in the oxidation of these pollutants, a catalytic wet air oxidation (CWAO) process was then tested using a platinum catalyst supported on multi-walled carbon nanotubes (CNT). In this CWAO process, the pharmaceuticals were dissolved together in ultra-pure water and in four natural water matrices—a reservoir water, a groundwater, and two waters from different municipal wastewater treatment plants. On the basis of the measurements of their removals, a discussion is given of the influence of the main operating variables: the presence or absence of catalyst, type of catalyst (the synthesized Pt/CNT or a commercial Pt/AC), catalyst dosage (0.005–0.050 g), temperature (120–140 °C), and oxygen pressure (20–40 bar). In most experiments, the removals were in the sequence: amoxicillin > naproxen > phenacetin. In addition, total organic carbon (TOC) removal measurements were made of some of the natural waters tested.  相似文献   
160.
Litter materials from forested watersheds can be a significant source of dissolved organic matter (DOM) to surface waters that can contribute to the formation of carcinogenic disinfection by-products (DBPs) during drinking-water chlorination. This study characterized the reactivity of DOM from litter leachates of representative vegetation in oak woodlands, a major plant community in the Foothill Region of California. Leachates from fresh and decomposed litter (duff) from two oak species, pine, and annual grasses were collected for an entire rainy season to evaluate their reactivity to form DBPs on chlorination. Relationships among specific ultraviolet absorbance (SΔUVA), fluorescence index (FI), specific differential ultraviolet absorbance (SΔUVA), specific chlorine demand (SCD), and the dissolved organic carbon:dissolved organic nitrogen (DOC:DON) ratio to the specific DBP formation potential (SDBP-FP) were examined. The DOM derived from litter materials had considerable reactivity in forming trihalomethanes (THMs) (1.80-3.49 mmol mol), haloacetic acid (HAAs) (1.62-2.76 mmol mol(-1)), haloacetonitriles (HANs) (0.12-0.37 mmol mol(-1)), and chloral hydrate (CHD) (0.16-0.28 mmol mol). These values are comparable to other identified watershed sources of DBP precursors reported for the California Delta, such as wetlands and organic soils. Vegetation type and litter decomposition stage (fresh litter versus 1-5 yr-old duff) were key factors that determined characteristics of DOM and their reactivity to form DBPs. Pine litter had significantly lower specific THM formation potential compared with oak and grass, and decomposed duff had a greater DON content, which is a precursor of HANs and other nitrogenous DBPs. The SΔUVA and SDBP-FP were temporally variable and dependent on vegetation type, degree of decomposition, and environmental conditions. Among the optical properties of DOM, SΔUVA was the only parameter that was consistently correlated with SDBP-FP.  相似文献   
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