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51.
Good genes are genetic elements that contribute to lifetime reproductive success, regardless of an individuals additional genotype. Their existence is debated, and most work has targeted their viability benefits to the offspring of choosy females. In the present study, we analyze a case of potential good genes effects in adult male sand lizards (Lacerta agilis). We show that males with a particular RFLP (Restriction Fragment Length Polymorphism) MHC genotype (O-males), as opposed to those that lack this genetic element (NO-males), have less ectoparasites under increasing physiological stress (indexed by baseline corticosterone level), and are not constrained by parasites at production of status coloration. Furthermore, O-males are more successful at mate acquisition and guard their partners longer. Ultimately, they have a higher genetic reproductive success as assigned by microsatellites.Communicated by W. Cooper  相似文献   
52.
Light duty vehicles, i.e. passenger cars and light trucks, account for approximately half of global transportation energy demand and, thus, a major share of carbon dioxide and other emissions from the transport sector. Energy consumption in the transport sector is expected to grow in the future, especially in developing countries. Cars with alternative powertrains to internal combustion engines (notably battery, hybrid and fuel-cell powertrains), in combination with potentially low carbon electricity or alternative fuels (notably hydrogen and methanol), can reduce energy demand by at least 50%, and carbon dioxide and regulated emissions much further. This article presents a comparative technical and economic assessment of promising future fuel/vehicle combinations. There are several promising technologies but no obvious winners. However, the electric drivetrain is a common denominator in the alternative powertrains and continued cost reductions are important for widespread deployment in future vehicles. Development paths from current fossil fuel based systems to future carbon-neutral supply systems appear to be flexible and a gradual phasing-in of new powertrains and carbon-neutral fluid fuels or electricity is technically possible. Technology development drivers and vehicle manufacturers are found mainly in industrialised countries, but developing countries represent a growing market and may have an increasingly important role in shaping the future.  相似文献   
53.
Plant species distributions are expected to shift and diversity is expected to decline as a result of global climate change, particularly in the Arctic where climate warming is amplified. We have recorded the changes in richness and abundance of vascular plants at Abisko, sub-Arctic Sweden, by re-sampling five studies consisting of seven datasets; one in the mountain birch forest and six at open sites. The oldest study was initiated in 1977-1979 and the latest in 1992. Total species number increased at all sites except for the birch forest site where richness decreased. We found no general pattern in how composition of vascular plants has changed over time. Three species, Calamagrostis lapponica, Carex vaginata and Salix reticulata, showed an overall increase in cover/frequency, while two Equisetum taxa decreased. Instead, we showed that the magnitude and direction of changes in species richness and composition differ among sites.  相似文献   
54.
The session on energy efficiency had no formal presentations and was organized as a panel discussion with four panelists. It was concluded that energy efficiency and saving measures on the short term is the most effective way to contribute to a sustainable energy system. Measures to improve and encourage energy efficiency should be implemented at all levels; municipal/local, national and super-national. Prices can be an effective instrument but need to be combined with systemic level measures. The transport sector was identified as the one with largest near future potential for increased energy efficiency. Agriculture and food is also an area with very large energy consumption and large potential for increased energy efficiency. The global population issue is yet another relevant, challenging and complex issue. It was noted that energy audits for end users in business and society increase awareness and insights into what they pay for, and they are likely to promote actions to save energy. Many measures are believed to suffer from Jevin’s paradox, i.e., that more efficient use of energy just leads to more energy consumption somewhere else. Many examples were given, however, where this does not happen. Another point put forward was that measures to make the energy system more efficient do not only mean constraints and regulations but also create great opportunities for market actors and societies.  相似文献   
55.
56.
在瑞典斯卡格拉克海峡沿岸,大叶藻(Zostera marina)是一种生长在浅水软海底上的优势显花植物.大叶藻场是许多甲壳动物和鱼类,不管是洄游种或是稳定种的重要群落生境.在20世纪80年代期间,作为海岸带管理的基础,对瑞典西海岸有大叶藻生长的沿岸浅水区的资源进行了调查.在这次研究中我们再次考察了斯卡格拉克海峡200km沿岸的5个沿海地区中的2000hm2大叶藻场.资源调查的方法(水下测量镜)与80年代的一样,但通过使用全球定位系统(GPS)增加了绘图的精确度.这次研究的结果表明,在10~15年的时间里,大叶藻的区域延伸面积减少了58%,且地区变化很大.大叶藻的减少主要限于大叶藻场的浅水部分.本文探讨了原因和生态后果.  相似文献   
57.
Environmental Science and Pollution Research - The sediments in the Grenland fjords in southern Norway are heavily contaminated by large emissions of dioxins and mercury from historic industrial...  相似文献   
58.
Besides gamma rays from 137Cs emanating from the Chernobyl accident, gamma rays from natural radionuclides are a dominant source of radiation exposure to the public. Since people spend much more time indoors than outdoors the radiation dose obtained inside dwellings contributes greatly to individual and collective doses. Dose rate measurements were made at 20 locations within the city of Göteborg and at further 22 reference sites within a radius of 100 km. Measurements were also made at Gävle and Lund. The dose rates were measured with RNI intensimeters, TLD (LiF) meters and in in situ measurements using an HPGe. The ground cover was grass, asphalt, concrete slates or paving-stones. The dose rates varied between 0.05 and 0.25 μSv/h. Also performed in different ways, measurements made inside and outside buildings at both Göteborg and Gävle showed inside dose rates higher than outside dose rates.  相似文献   
59.
Stern S  Sonesson U  Gunnarsson S  Oborn I  Kumm KI  Nybrant T 《Ambio》2005,34(4-5):402-407
To study future, sustainable production systems, a step-wise method was used to create three future scenarios for pig production based on different sustainability goals. The first scenario focused on animal welfare and the natural behavior of the animals. The second targeted low impacts on the environment and the efficient use of natural resources. The third scenario aimed at product quality and safety. Each scenario fulfilled different aspects of sustainability, but there were goal conflicts because no scenario fulfilled all sustainability goals. The scenarios were then parameterized. The environmental impact was calculated using the life-cycle assessment (LCA) methodology, and the economic cost was calculated from the same data set. The cost per kilo of pork was highest for the animal welfare scenario and similar for the other two scenarios. The environmental scenario had the lowest environmental impact, and the product-quality scenario the highest. The results are discussed based on different future priorities.  相似文献   
60.
Growing juveniles of the spruce-living spider Pityohyphantes phrygianus were sprayed with water of different acidity--pH approximately 7 (control), 4.0 (acid rain) and 2.2-in a 2.5-month laboratory experiment. The growth rates did not differ between control and pH 4.0, while there was a significant growth reduction at pH 2.2. A low mortality occurred only in the pH 2.2 group. P. phrygianus seems to be resistant against acid rain although negative long-term effects cannot be ruled out.  相似文献   
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