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91.
The Swedish coastal zone is a scene of conflicting interests about various goods and services provided by nature. Open-access conditions and the public nature of many services increase the difficulty in resolving these conflicts. "Sustainability" is a vague but widely accepted guideline for finding reasonable trade-offs between different interests. The UN view of sustainable development suggests that coastal zone management should aim at a sustainable ecological, economic, and social-cultural development. Looking closer at economic sustainability, it is observed that economic analyses about whether changes in society imply a gain or a loss should take into account the economic value of the environment. Methods used for making such economic valuation in the context of the Swedish coastal zone are briefly reviewed. It is noted that the property rights context matters for the results of a valuation study. This general background is followed by a concise presentation of the design and results of four valuation studies on Swedish coastal zone issues. One study is on the economic value of an improved bathing water quality in the Stockholm archipelago. The other studies are a travel cost study about the economic value of improved recreational fisheries in the Stockholm archipelago, a replacement cost study on the value of restoring habitats for sea trout, and a choice experiment study on the economic value of improved water quality along the Swedish westcoast.  相似文献   
92.
在环境监测中,监测系统在非预期事件出现时能够发出早期预警是很重要的.这些事件具有突发,或者难以观测到的性质.在设计这类监测系统时,必须在成本和风险之间达到一个适当的平衡.传统意义上有两类和早期预警系统相关联的风险,即没有检测到重要变化的风险和错误预警的风险.本文的目的是阐述一种在考虑了传统类型的风险和成本的情况下来比较不同监测系统性能的方法.这个方法被试用于地衣植被的监测中,并采用预期效应作为性能的度量标准.在估计事件的概率时,应用了空间微观模拟技术(spatial microsimulation)和蒙特卡罗模拟技术.所评估的监测计划基于卫星图像、航空照片、野外采样和土地覆被图.研究的主要结论是,标准化质量度量在环境监测方法可用性的评估中是极为有用的.另外,空间微观模拟技术在效益和成本估计中是可用的.不过要改进算法,还需要应用宏观约束(macroconstraints)来修正模拟模型.  相似文献   
93.
本文利用非侵入计算层析X射线摄影法(pQCT)研究了雄性波罗的海灰海豹(4~23岁龄)骨组织的矿物密度(mg/cm3).资料按照收集的年份分组.A组1850~1955年,有机氯(OCs)大量引入之前的时期;B组1965~1985年,OC污染十分严重的时期;C组1986~1997年,OCs浓度逐渐减小的时期.测量结果的复现性良好,变异系数(CV)为0.1%~2.1%.1986~1997年收集的标本中桡骨小梁的矿物密度比1965~1985年收集的标本的明显要高(p<0.05).1986~1997年收集的标本中,下颌骨的皮层骨矿物密度明显地低于1850~1955年收集的标本(p<0.05).这些结果表明小梁和皮层骨在一段时间内的不同响应.在OC污染非常严重的时期(1965~1985年),小梁骨矿物密度最低,而在1985~1997年收集的标本中,皮层骨密度最低,该时段是一个OC污染程度相当低的时期.有关这些效应背后的机制目前尚不知道.但是,可以假定这里涉及到OCs.由于目前缺乏有关研究个体中OCs残留水平的资料,因此不可能评估OCs在这方面的影响.  相似文献   
94.
Individual male sand lizards meet repeatedly during mate search and engage in costly interactions. If males can recognize rivals, the number of costly fights with a predictable outcome may be reduced. In staged contests between males, second interactions are on average significantly shorter than first ones, suggesting individual recognition. When aggressive behavior differs substantially between the sexes, the more aggressive sex may be predicted to have more variation in skin traits located on the parts of the body displayed during contests; this would facilitate individual recognition. Male (aggressive) sand lizards are more variable in two of three lateral skin traits displayed during males' contests, while females (non-aggressive) are more variable in one dorsal skin trait; in four other dorsal traits there was no difference in variability between the sexes.  相似文献   
95.
A screening life cycle assessment (LCA) of tomato ketchup has been carried out. The purpose was to identify ‘hot-spots', that is parts of the life-cycle that are important to the total environmental impact. The system investigated includes agricultural production, industrial refining, packaging, transportation, consumption and waste management. Energy use and emissions were quantified and some of the potential environmental effects assessed. Packaging and food processing were found to be hot-spots for many, but not all, of the impact categories investigated. For primary energy use, the storage time in a refrigerator (household phase) was found to be a critical parameter.  相似文献   
96.
We provide evidence that male lizards can use chemosensory cues to identify individual females and probably therefore maintain long-term associations with these females in the wild. In the laboratory, males preferentially followed the scent trail of their vitellogenic female “partner” rather than that of another vitellogenic female. Our 5-year field study of the small viviparous scincid lizard (Niveoscincus microlepidotus) in alpine Tasmania showed that sexually mature males and females commonly formed “pairs” for long periods (on average 29 days). These pairs occurred primarily during the mating season, always involved one adult male and one adult female, and usually involved vitellogenic rather than gravid females. Our laboratory experiments suggest that a significant factor in maintaining those prolonged partnerships is male scent trailing of partners. Received: 28 October 1997 / Accepted after revision: 28 May 1998  相似文献   
97.
Objective Cell free foetal DNA (cff DNA) extracted from maternal plasma is now recognized as a potential source for prenatal diagnosis but the methodology is currently not well standardized. To evaluate different manual and automated DNA extraction methods with a view to developing standards, an International Workshop was performed. Methods Three plasma pools from RhD-negative pregnant women, a DNA standard, real-time-PCR protocol, primers and probes for RHD were sent to 12 laboratories and also to one company (Qiagen, Hilden, Germany). In pre-tests, pool 3 showed a low cff DNA concentration, pool 1 showed a higher concentration and pool 2 an intermediate concentration. Results The QIAamp DSP Virus Kit, the High Pure PCR Template Preparation Kit, an in-house protocol using the QIAamp DNA Blood Mini Kit, the CST genomic DNA purification kit, the Magna Pure LC, the MDx, the M48, the EZ1 and an in-house protocol using magnetic beads for manual and automated extraction were the methods that were able to reliably detect foetal RHD. The best results were obtained with the QIAamp DSP Virus Kit. The QIAamp DNA Blood Mini Kit showed very comparable results in laboratories that followed the manufacturer's protocol and started with ≥ 500 µL plasma. One participant using the QIAamp DNA Blood Midi Kit failed to detect reliably RHD in pool 3. Conclusions This workshop initiated a standardization process for extraction of cff DNA in maternal plasma. The highest yield was obtained by the QIAamp DSP Virus Kit, a result that will be evaluated in more detail in future studies. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   
98.
Tyler G  Olsson T 《Chemosphere》2006,65(2):250-260
The amounts of sixty elements in developing, maturing, senescent and wilting leaves, and in the wintering dead leaves attached to the branches, are reported for a beech (Fagus sylvatica) forest on mor Podzol in south Sweden, a site with no local sources of pollution or geological anomalies. The amounts (contents per leaf) of K (potassium), Rb (rubidium), Cs (caesium), Cu (copper) and P (phosphorus) were highest in young leaves, decreasing throughout the growing season and usually in the subsequent winter. The entirely opposite pattern with a continuous, mostly even increase of the amounts was measured with Be (beryllium), Ba (barium), Hg (mercury), Al (aluminium), Tl (thallium), Pb (lead), Bi (bismuth), V (vanadium), W (tungsten), As (arsenic), Sb (antimony), and Se (selenium). Amounts of rare-earth elements and some transition metals, such as Co (cobalt), Ti (titanium), and the actinides Th (thorium) and U (uranium) were more stable during the growing season, after an initial increase in early summer, but increased greatly in the winter. This winter increase in dead attached leaves has to be accounted for by uptake from long-distance transported constituents in dry and wet deposition. It was similar to deposition rate estimates using moss carpets from the same locality. A passive uptake was positively related to ionic charge and atomic mass. However, the amounts of several, mainly non-essential elements, such as Ni (nickel), Sc (scandium), Zr (zirconium), Cr (chromium), Ag (silver), and Cd (cadmium) were not much lower in the young or maturing leaves than in the wintered dead leaves of this deciduous (hardwood) forest and a proportion apparently originated from internal translocation in the trees. Seasonal fluxes or cycling of many of the scarce or rare elements reported here have never been studied before in forest ecosystems.  相似文献   
99.
The reproduction of white-tailed sea eagles was monitored in 1964-1999 in 3 differently contaminated sub-populations: Baltic Sea coast (Bp), inland central Sweden (Ip) and Lapland (Lp). 249 dead eggs from 205 clutches were obtained for analyses of DDE and PCBs and for eggshell measurements. A desiccation index (Di) value was calculated for each egg as a measure of water loss through the shell. In the highly contaminated Bp, p,p'-DDE concentrations in the eggs decreased continuously and 5-fold during the study period and PCB concentrations decreased 3-fold from the mid 1980s. The PCB pattern changed slightly over time towards more high-chlorinated congeners but the relative toxicity of the PCB mixture, expressed as 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TEQ), remained constant and TEQ can be assumed to have decreased in a similar way as PCB over time. Productivity (P), shell thickness (St), shell index (Si) and Di increased over time in the Bp but no change in Di or productivity occurred in the Lp, where residue concentrations were 5-8 times lower. P of the Bp was not correlated to St or Si but was negatively correlated to Di, DDE and PCB. An S-shaped dose-response relationship was indicated between P and DDE. After 1988, when the PCB/DDE ratio was considerably higher than previously, PCB but not DDE concentrations were significantly higher in eggs with dead embryos as compared to undeveloped eggs, implying lethal concentrations of PCB, and a LOEL of 320 pg g-1 TEQ is suggested for embryo mortality. In a subset of 21 eggs, representing productive and unproductive females, analyzed for a selection of coplanar PCB congeners, tris(4-chlorophenyl) methanol and bis(4-chlorophenyl) sulphone, there was no evidence for a correlation between P and any of these compounds. A reduction in residue concentrations in old females did not lead to increased P or improved Di-values, indicating a remaining effect from a previous, higher exposure to contaminants. The inability to reproduce included a high rate of undeveloped eggs, indicating effects at a prezygotic stage. P showed the strongest correlation with Di, and Di was most strongly correlated to DDE. Thus, the remaining effect of previous exposure resulted in a stronger correlation to the symptom (Di) rather than to the suggested causative agent (DDE). LOEL values for depressed P were estimated at 120 micrograms g-1 DDE and 500 micrograms g-1 PCB (lipid basis). It is concluded that the major reason for depressed P during the study period was DDE, but that effects also from PCB were largely concealed by the effects from DDE.  相似文献   
100.
肉产品的技术、营养和感官品质在屠宰前后可能会受到多种交互作用因素的影响.从文献来看,以创造猪肉可持续生产体系为目标的各种变革,通常对肉的最终pH值没有影响或影响较小.一些研究表明,可持续生产体系降低了猪肉的持水能力.与常规饲养体系相比,户外生产被认为更能增加猪肉的剪切力值.肉色的影响因素很多,这些因素可能导致猪肉颜色更暗、色素含量增加,或猪肉颜色更浅淡、结构有所变化.在使用含有多不饱和脂肪酸饲料的生产体系中,肉产品所含类脂的不饱和性更强,肉产品的营养价值更高.一句话,必须考虑各因素间的组合效应如:饲养、生产体系、遗传型、性别和宰前处理等对肉品质量的影响.  相似文献   
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