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61.
OBJECTIVES: The horizontal distance between the back of the head and the frontal of the head restraint (backset) and rearward head movement relative to the torso (cervical retraction) were studied in different occupant postures and positions in a modern car. METHODS: A stratified randomized population of 154 test subjects was studied in a Volvo V70 year model 2003 car, in driver, front passenger, and rear passenger position. In each position, the subjects adopted (i) a self-selected posture, (ii) a sagging posture, and (iii) an erect posture. Cervical retraction, backset, and vertical distance from the top of the head restraint to the occipital protuberance in the back of the head of the test subject were measured. These data were analyzed using repeated measures ANOVA and linear regression analysis with a significance level set to p < 0.05. RESULTS: In the self-selected posture, the average backset was 61 mm for drivers, 29 mm for front passengers, and 103 mm for rear passengers (p < 0.001). Women had lower mean backset (40 mm) than men (81 mm), particularly in the self-selected driving position. Backset was larger and cervical retraction capacity lower in the sagging posture than in the self-selected posture for occupants in all three occupant positions. Rear passengers had the largest backset values. Backset values decreased with increased age. The average cervical retraction capacity in self-selected posture was 35 mm for drivers, 30 mm for front passengers, and 33 mm for rear passengers (p < 0.001). CONCLUSIONS: Future design of rear-end impact protection may take these study results into account when trying to reduce backset before impact. Our results might be used for future development and use of BioRID manikins and rear-end tests in consumer rating test programs such as Euro-NCAP. 相似文献
62.
Some western Norwegian fjords host extraordinarily abundant and persistent populations of the mesopelagic, coronate scyphomedusa,
Periphylla periphylla. In these environments, from late autumn to spring, the medusae undertake regular diel vertical migrations into surface waters.
From unique observations obtained with a remotely operated vehicle (ROV), including observations made without artificial light,
we observed that 90% of the medusae swam with their tentacles in aboral position. Stomach content analyses of surface-collected
specimens revealed that the medusae ate mainly calanoid copepods, but ostracods and large euphausiids were also prominent
components of their diets. The clearance rate potential of P. periphylla, assessed from in situ observations and stomach contents, was comparable to that of similar-sized, epipelagic gelatinous
species. Our findings suggest that P. periphylla behave as active predators in surface waters. 相似文献
63.
Maximilian Berthold Ulf Karsten Mario von Weber Alexander Bachor Rhena Schumann 《Ambio》2018,47(1):146-158
The EU-water framework directive aims at nutrient reductions, since anthropogenically induced eutrophication is a major threat for coastal waters. However, phytoplankton biomass in southern Baltic Sea coastal water bodies (CWB) remains high and the underlying mechanisms are not well understood. Therefore, a CWB data set was analysed regarding changes in phytoplankton biomass and nutrient concentration of nitrogen (N) and phosphorus (P) from 2000 to 2014. It was expected to find imbalances between produced phytoplankton biomass and total nutrient concentrations. Inner CWB were cyanobacteria-dominated and showed up to five times higher chlorophyll a-concentrations compared to outer CWB with similar total phosphorus-concentrations. Phytoplankton tended to be P-limited during spring and N-limited during summer. Phytoplankton biomass and nutrient concentrations were even higher during very humid years, which indicated a close coupling of the CWB with their catchment areas. This study suggests that re-mesotrophication efforts need to consider the importance of changed phytoplankton composition and nutrient availabilities. 相似文献
64.
Henne Paul D. Bigalke Moritz Büntgen Ulf Colombaroli Daniele Conedera Marco Feller Urs Frank David Fuhrer Jürg Grosjean Martin Heiri Oliver Luterbacher Jürg Mestrot Adrien Rigling Andreas Rössler Ole Rohr Christian Rutishauser This Schwikowski Margit Stampfli Andreas Szidat Sönke Theurillat Jean-Paul Weingartner Rolf Wilcke Wolfgang Tinner Willy 《Regional Environmental Change》2018,18(1):205-221
Regional Environmental Change - Planning for the future requires a detailed understanding of how climate change affects a wide range of systems at spatial scales that are relevant to humans.... 相似文献
65.
Ongoing marine monitoring programs are seldom designed to detect changes in the environment between different years, mainly due to the high number of samples required for a sufficient statistical precision. We here show that pooling over time (time integration) of seasonal measurements provides an efficient method of reducing variability, thereby improving the precision and power in detecting inter-annual differences. Such data from weekly environmental sensor profiles at 21 stations in the northern Bothnian Sea was used in a cost-precision spatio-temporal allocation model. Time-integrated averages for six different variables over 6 months from a rather heterogeneous area showed low variability between stations (coefficient of variation, CV, range of 0.6–12.4%) compared to variability between stations in a single day (CV range 2.4–88.6%), or variability over time for a single station (CV range 0.4–110.7%). Reduced sampling frequency from weekly to approximately monthly sampling did not change the results markedly, whereas lower frequency differed more from results with weekly sampling. With monthly sampling, high precision and power of estimates could therefore be achieved with a low number of stations. With input of cost factors like ship time, labor, and analyses, the model can predict the cost for a given required precision in the time-integrated average of each variable by optimizing sampling allocation. A following power analysis can provide information on minimum sample size to detect differences between years with a required power. Alternatively, the model can predict the precision of annual means for the included variables when the program has a pre-defined budget. Use of time-integrated results from sampling stations with different areal coverage and environmental heterogeneity can thus be an efficient strategy to detect environmental differences between single years, as well as a long-term temporal trend. Use of the presented allocation model will then help to minimize the cost and effort of a monitoring program. 相似文献
66.
The Application of IUCN Red List Criteria at Regional Levels 总被引:13,自引:1,他引:12
Ulf Gärdenfors†‡§ Craig Hilton-Taylor†‡§ Georgina M. Mace†‡§ Jon Paul Rodríguez†‡§ 《Conservation biology》2001,15(5):1206-1212
This paper represents a work in progress by the World Conservation Union (IUCN). Earlier drafts of the work have appeared in IUCN publications, but the "International Issues" section of Conservation Biology seems an appropriate and important place to publish the penultimate version of the document. Comments on this issue in general or on the approach taken by the IUCN should be sent to the authors directly.
Joshua Ginsburg 相似文献
Joshua Ginsburg 相似文献
67.
By mainly targeting larger predatory fish, commercial fisheries have indirectly promoted rapid increases in densities of their
prey; smaller predatory fish like sprat, stickleback and gobies. This process, known as mesopredator release, has effectively
transformed many marine offshore basins into mesopredator-dominated ecosystems. In this article, we discuss recent indications
of trophic cascades on the Atlantic and Baltic coasts of Sweden, where increased abundances of mesopredatory fish are linked
to increased nearshore production and biomass of ephemeral algae. Based on synthesis of monitoring data, we suggest that offshore
exploitation of larger predatory fish has contributed to the increase in mesopredator fish also along the coasts, with indirect
negative effects on important benthic habitats and coastal water quality. The results emphasize the need to rebuild offshore
and coastal populations of larger predatory fish to levels where they regain their control over lower trophic levels and important
links between offshore and coastal systems are restored. 相似文献
68.
Johan Eriksson Ulf Skyllberg 《Environmental pollution (Barking, Essex : 1987)》2009,157(11):3010-3015
Aniline and 2,4,6-trinitrotoluene (TNT) were equilibrated with particulate (POM) and dissolved organic matter (DOM) from an organic soil at different compositions of adsorbed major cations (Na, Al) and pH (aniline: 3.7–5.1, TNT: 4.8–5.0). After separation of POM, concentrations of 14C-labelled aniline and TNT* (including TNT degradation products) were determined in DOM size fractions using size-exclusion chromatography (SEC) and UV-detection. Concentrations in the <3.5 kDa size fraction were 2.8–6.0 and 8.5–9.5 times higher for aniline and TNT*, respectively, as compared to the >40 kDa fraction. Thus, both aniline and TNT* were preferentially associated to the smallest DOM size fraction. The significant binding to DOM (similar extent as to POM) and the fact that the <3.5 kDa DOM fraction was less susceptible to flocculation by major metals suggests that the mobility of aniline and TNT is highly affected by the solubility of soil organic matter. 相似文献
69.
Ingrid Öborn Jan Bengtsson Fredrik Hedenus Lotta Rydhmer Maria Stenström Katarina Vrede Charles Westin Ulf Magnusson 《Ambio》2013,42(7):823-839
To increase the awareness of society to the challenges of global food security, we developed five contrasting global and European scenarios for 2050 and used these to identify important issues for future agricultural research. Using a scenario development method known as morphological analysis, scenarios were constructed that took economic, political, technical, and environmental factors into account. With the scenarios as a starting point future challenges were discussed and research issues and questions were identified in an interactive process with stakeholders and researchers. Based on the outcome of this process, six socioeconomic and biophysical overarching challenges for future agricultural were formulated and related research issues identified. The outcome was compared with research priorities generated in five other research programs. In comparison, our research questions focus more on societal values and the role of consumers in influencing agricultural production, as well as on policy formulation and resolving conflicting goals, areas that are presently under-represented in agricultural research. The partly new and more interdisciplinary research priorities identified in Future Agriculture compared to other programs analyzed are likely a result of the methodological approach used, combining scenarios and interaction between stakeholders and researchers. 相似文献
70.
A Dynamic Simulation Model of Land-Use, Population, and Rural Livelihoods in the Central Rift Valley of Ethiopia 总被引:1,自引:0,他引:1
The dynamic interactions between society and land resources have to be taken into account when planning and managing natural
resources. A computer model, using STELLA software, was developed through active participation of purposively selected farm
households from different wealth groups, age groups and gender within a rural community and some members of Kebelle council.
The aim of the modeling was to study the perceived changes in land-use, population and livelihoods over the next 30 years
and to improve our understanding of the interactions among them. The modeling output is characterized by rapid population
growth, declining farm size and household incomes, deteriorating woody vegetation cover and worsening land degradation if
current conditions remain. However, through integrated intervention strategies (including forest increase, micro-finance,
family planning, health and education) the woody vegetation cover is likely to increase in the landscape, population growth
is likely to slow down and households’ income is likely to improve. A validation assessment of the simulation model based
on historical data on land-use and population from 1973 to 2006 showed that the model is relatively robust. We conclude that
as a supporting tool, the simulation model can contribute to the decision making process. 相似文献