Groundwater resources are at risk from pollution, climate change and land-management practices. Long-term forecast is a tool to demonstrate future development and to support decisions on measures which can be implemented, controlled and eventually corrected. As the basis for preventive action, a forecast can be viewed as a key to groundwater protection. The soil zone plays a vital role in groundwater protection. Research on soil and groundwater trends, as affected by change of climate and/or land-management practices, is on the agenda. Integrated research is necessary to develop numerical soil-water system models reflecting all relevant transport processes at various scales. Even relatively simple problems like forecasting pollutant release from contaminated materials are difficult to resolve. Batch tests may be sufficient in low-risk cases. At higher risk when contaminated substrates are chosen for deposition on a large scale, a thorough characterization of the materials is necessary covering all aspects of stability and possible changes of the environment. 相似文献
We analyzed how offspring sex ratio varies with maternal condition in order to obtain evidence on the population structure in two aphid species with different life cycles. When fitness returns per unit investment differ for the production of daughters and sons, selection will favor an increasing investment into the sex with the higher returns. Therefore, the offspring sex ratios of individual mothers should become more biased towards the sex with the higher fitness returns as their condition or fecundity improves. The pattern of sex ratio adjustment we found in Uroleucon cirsii indicates local mate competition among males, while the pattern we found in Rhopalosiphum padi suggests local resource competition among sexual females. This might be the first evidence for local resource competition among females in an invertebrate species. Local mate competition means that fitness returns are limited by the availability of females as mates within local breeding groups, whereas local resource competition means that fitness returns are limited by the availability of resources for females competing within local groups. We discuss how the life cycles of both species fit to these hypotheses.
Joachim L. DaggEmail: Phone: +49-551-393730Fax: +49-551-3912105
Chemical orientation of the European cockchafer, Melolontha melolontha L., a serious pest in agriculture and horticulture, was investigated by field tests and electrophysiological experiments using plant volatiles. In total, 16 typical plant volatiles were shown to elicit electrophysiological responses in male cockchafers. Funnel trap field bioassays revealed that green leaf alcohols (i.e. (Z)-3-hexen-1-ol, (E)-2-hexen-1-ol and 1-hexanol) attracted males, whereas the corresponding aldehydes and acetates were behaviourally inactive. Furthermore, male cockchafers were attracted by volatiles from mechanically damaged leaves of Fagus sylvatica L., Quercus robur L. and Carpinus betulus L. However, volatiles emitted by damaged leaves of F. sylvatica attracted significantly more males than those from the other host plants. Odour from intact F. sylvatica leaves was not attractive to M. melolontha males. Females were not attracted by any of the tested volatile sources. The results suggest that plant volatiles play a similar role as a sexual kairomone in mate finding of M. melolontha, as has been shown for the forest cockchafer, Melolontha hippocastani F. Nevertheless, both species show remarkable differences in their reaction to green leaf alcohols. 相似文献
Although studies on the evolution and function of female ornaments have become more numerous in the last years, the majority
of these studies were carried out in cases where female ornaments were a smaller and duller version of the ornaments found
in males. There are substantially fewer studies on species with female-specific ornaments. However, no study so far investigated
the potential of female-specific colouration as a quality signal in birds with conventional sex roles. We studied female-specific
ornamentation in a strongly sexually dichromatic species, the upland goose Chloephaga picta leucoptera, in two consecutive years. Male upland geese have white head and breast feathers and black legs, whereas females have reddish-brown
head and breast feathers and conspicuous yellow-orange legs. We found that female-specific colouration in upland geese can
reliably indicate different aspects of female phenotypic quality. Females with more orange coloured legs and more red-like
head colours had higher clutch and egg volumes than females with a paler leg and head colouration, and a more reddish plumage
colouration was related to a higher body condition. These relationships provide the theoretic possibility for males to assess
female phenotypic quality on the basis of colouration. Furthermore, the females with a more orange-like tarsus colouration
had higher plasma carotenoid levels. Both tarsus colouration and carotenoid concentrations of individual females were highly
correlated across years, indicating that tarsus colour is a stable signal. Despite this correlation, small individual differences
in plasma carotenoid concentrations between the two study years were related to differences in tarsus colouration. We thus
show for the first time in a wild bird and under natural conditions that carotenoid-based integument colouration remains consistent
between individuals in consecutive years and is also a dynamic trait reflecting individual changes in carotenoid levels. In
this species, where pairs form life-long bonds, the honesty of the carotenoid-based integument colouration suggests that it
may be a sexually selected female ornament that has evolved through male mate choice. 相似文献
Objective: Norway introduced a “Vision Zero” strategy in 2001, using multiple approaches, aiming toward a future in which no one will be killed or seriously injured in road traffic crashes (RTCs). Official statistics show that the number of fatally injured road users has declined substantially from 341 deaths in 2000 to 117 in 2015. In-depth crash investigations of all fatal RTCs started in Norway in 2005. The aim of this study was to investigate whether fatal crash characteristics, vehicle safety features, and prevalence of drugs and/or alcohol among fatally injured drivers and riders has changed during 2005–2015, accompanying the reduction in road fatalities.
Methods: Data on all car/van drivers and motorcycle/moped riders fatally injured in RTCs during 2005–2015 were extracted from Norwegian road traffic crash registries and combined with forensic toxicology data.
Results: The proportion of cars and motorcycles with antilock braking systems and cars with electronic stability control, increased significantly during the study period. The prevalence of nonuse of seat belts/helmets and speeding declined among both fatally injured drivers and riders. In addition, the prevalence of alcohol declined, though no significant change in the total prevalence of other substances was noted.
Conclusion: The observed changes toward more safety installations in cars and motorcycles and lower prevalence of driver-related risk factors like alcohol use, speeding, and nonuse of seat belts/helmets among fatally injured drivers/riders may have contributed to the decrease in road traffic deaths. 相似文献
Conformity assessment procedures prescribed by European legislation are presented and their concrete implementation is illustrated by the example of personal protective equipment (PPE). The different categories of PPE defined by Council Directive 89/686/EEC are explained with reference to the applicable conformity assessment elements. Quality assurance of production is presented as the central element of the conformity assessment procedure for complex PPE. Special emphasis is put on the necessity of having a regular exchange of views and information among notified bodies in Europe. Ways in which third countries can eventually carry out conformity assessment on the basis of a contract with the European Community Commission are explained. 相似文献