罗布泊野骆驼国家级自然保护区野骆驼的栖息环境及适应特征

野骆驼是世界上骆驼科真驼属唯存的野生种,目前全世界只分布在我国新疆和蒙古国的中蒙边境地区,在世界上仅存730~880头左右,是比大熊猫更为珍稀的野生动物,濒临灭绝。野骆驼的生存环境非常恶劣,气候十分干旱,荒漠化十分严重,蒸发量远远大于降雨量,空气非常干燥,日夜温差极大。分布区的植物也非常稀少,没有淡水,只有零星散布的又苦又咸的盐泉,大部分地区寸草不生,只有在盐泉附近长着稀稀拉拉的盐生草、沙拐枣、骆驼刺等。野骆驼能在严酷的荒漠半荒漠地区生活,对恶劣气候环境有很强的适应性,具有耐饥渴抗风暴等抵抗恶劣环境的能力,是动物界中任何一种动物无可比拟的。     

Pesticide residue removal in classic domestic processing of tomato and its effects on product quality

This study was undertaken to evaluate the effectiveness of several household practices (washing with water or acidic, alkaline, and oxidizing solutions, and peeling) in minimizing pesticide residue contamination of tomatoes, as well as the impact on the quality of the treated fruit. Tests were performed using two systemic fungicides (azoxystrobin and difenoconazole) and one contact fungicide (chlorothalonil). Solid-liquid extraction with low temperature partition (SLE/LTP) and liquid-liquid extraction with low temperature partition (LLE/LTP) were used to prepare the samples for pesticides determination by gas chromatography. Washing the tomatoes with water removed approximately 44% of chlorothalonil, 26% of difenoconazole, and 17% of azoxystrobin. Sodium bicarbonate (5%) and acetic acid (5%) solutions were more efficient, removing between 32 and 83% of the residues, while peeling removed from 68 to 88% of the pesticides. The washing solutions altered some fruit quality parameters, including acidity and chroma, and also caused weight loss. Acetic acid (0.15 and 5%) and hypochlorite (1%) solutions had the greatest effect on these parameters.     

Sand as a relevant fraction in geochemical studies in intertidal environments

Soil and sediment samples from several intertidal environment exposed to different types of contamination were studied to investigate the importance of grain size in relation to the capacity of the substrates to retain trace metals. The unfractionated samples (referred to as bulk samples) were separated into the following grain/size fractions: fine–coarse sand (2?0.100 mm), very fine sand (0.100?0.050 mm), silt (0.050?0.002 mm), and clay (0.002 mm). The sample into its fractions was carried out was in a glove box under high-purity N₂ atmosphere in order to minimize any alterations to the samples. The bulk samples were characterized in terms of physicochemical properties such as pH, redox potential, and grain size. The total organic carbon (TOC), total sulfur (S), iron (Fe) pyrite, Fe, and manganese (Mn), and trace metals lead (Pb), mercury (Hg), chromium (Cr), and nickel (Ni) were analyzed in the bulk samples and in each fraction. The sand fractions were also examined by scanning electron microscopy (SEM). Comparisons of the above parameters were made between fractions and between each fraction and the corresponding bulk sample. The fine–coarse sand fraction contained high levels of the primary elements of the geochemical processes that occur in marine sedimentary environments such as TOC, total Fe, Mn, and S. The net concentrations of these four elements were higher in the fine-coarse sand fraction than in the very fine sand fraction and were similar to the net concentrations in the silt and clay fractions. Detailed SEM analysis of the sand coarse fraction revealed the presence of Fe and aluminum oxyhydroxide coatings in the oxic layers, whereas the framboidal pyrites and coatings observed in the anoxic layers were Fe sulfides. The presence of the various coatings explains why the trace metal concentrations in the sand fine–coarse fraction were similar to those in the clay fraction and higher than those in the very fine sand fraction. The present results highlight the importance of the sand fraction, which is generally disregarded in geochemical and environmental studies of sedimentary layers.     

CHEMICAL ANALYSIS OF CO2 REMOVAL IN TRAY AERATORS1

ABSTRACT: This paper presents a discussion of the chemistry of CO₂ removal in tray aerators, and different sets of equations that are applicable to several initial water chemical conditions are proposed. These chemical equations and a statistical model to predict the kinetic constant were tested with field data observed by other researchers in pilot units and in a full scale plant. The water temperature in their experiments was around 15°C.     

Cryo-comminution of plastic waste

Recycling of plastics is a big issue in terms of environmental sustainability and of waste management. The development of proper technologies for plastic recycling is recognised as a priority. To achieve this aim, the technologies applied in mineral processing can be adapted to recycling systems. In particular, the improvement of comminution technologies is one of the main actions to improve the quality of recycled plastics. The aim of this work is to point out suitable comminution processes for different types of plastic waste. Laboratory comminution tests have been carried out under different conditions of temperature and sample pre-conditioning adopting as refrigerant agents CO2 and liquid nitrogen. The temperature has been monitored by thermocouples placed in the milling chamber. Also different internal mill screens have been adopted. A proper procedure has been set up in order to obtain a selective comminution and a size reduction suitable for further separation treatment. Tests have been performed on plastics coming from medical plastic waste and from a plant for spent lead batteries recycling. Results coming from different mill devices have been compared taking into consideration different indexes for representative size distributions. The results of the performed tests show as cryo-comminution improves the effectiveness of size reduction of plastics, promotes liberation of constituents and increases specific surface size of comminuted particles in comparison to a comminution process carried out at room temperature.     

Response of Ceriodaphnia dubia to ionic silver: discrepancies among model predictions, measured concentrations and mortality

Silver thiosulfate, often a waste product of photoprocessing, is less bioavailable or toxic to aquatic organisms than is ionic silver. We conducted duplicate 48-h Ceriodaphnia dubia tests in reconstituted laboratory water using treatments of 92.7 nM Ag+ with various concentrations of thiosulfate. Expected Ag+ concentrations were generated for thiosulfate treatment levels using MINEQL + chemical equilibrium modeling. Ag+ concentrations in treatments were determined using a novel silicon-based sensor. Based on predicted Ag+ and published 48-h LC50 values for C. dubia, we did not expect to observe adverse effects. Yet, 100% mortality was observed at low thiosulfate treatments, whereas > 85% and > 95% survival was observed at higher thiosulfate treatment levels, respectively. Our results indicate that biotic responses match the sensor-based Ag+ concentrations. However, there is a discrepancy between these empirical results and responses expected to occur with Ag+ concentrations as predicted by MINEQL + chemical modeling. By correlating silicon sensor data with toxicity results obtained from our laboratory, our work clearly relates a specific chemical form (Ag+) to toxicity results.     

Climate change mitigation policy paradigms—national objectives and alignments

The aim of this paper is to assess how policy goals in relation to the promotion of green growth, energy security, pollution control and greenhouse gas (GHG) emissions reductions have been aligned in policies that have been implemented in selected countries during the last decades as a basis for discussing how a multi objective policy paradigm can contribute to future climate change mitigation. The paper includes country case studies from Brazil, Canada, China, the European Union (EU), India, Japan, Mexico, Nigeria, South Africa, South Korea and the United States covering renewable energy options, industry, transportation, the residential sector and cross-sectoral policies. These countries and regions together contribute more than two thirds of global GHG emissions. The paper finds that policies that are nationally driven and that have multiple objectives, including climate-change mitigation, have been widely applied for decades in both developing countries and industrialised countries. Many of these policies have a long history, and adjustments have taken place based on experience and cost effectiveness concerns. Various energy and climate-change policy goals have worked together in these countries, and in practice a mix of policies reflecting specific priorities and contexts have been pursued. In this way, climate-change mitigation has been aligned with other policy objectives and integrated into broader policy packages, though in many cases specific attention has not been given to the achievement of large GHG emission reductions. Based on these experiences with policy implementation, the paper highlights a number of key coordination and design issues that are pertinent to the successful joint implementation of several energy and climate-change policy goals.     

A screening procedure to measure the effect of uncertainty in air emission estimates

Mitigation and Adaptation Strategies for Global Change - Emission inventories are compiled at regional level. When these sources of information are used, uncertainty of emission estimates is never...     

Intraventricular haemorrhage in a fetus with cerebral cytomegalovirus infection

Cytomegalovirus (CMV) is the leading infectious cause of prenatal neurological damage, which is particularly severe when primary maternal infection occurs during the first 16 weeks of gestation, at the time of organ development and neuronal migration. Vascular involvement has been suggested to be among thepossible pathogenic mechanisms of virus-induced pathology, in addition to direct viral effects. We report on a fetus with cerebral CMV infection, which had intraventricular haemorrhage, together with oligohydramnios and hyperechogenic bowel, following maternal primary CMV infection. Copyright © 2002 John Wiley & Sons, Ltd.