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981.
Controlling invasive species is critical for conservation but can have unintended consequences for native species and divert resources away from other efforts. This dilemma occurs on a grand scale in the North American Great Lakes, where dams and culverts block tributary access to habitat of desirable fish species and are a lynchpin of long‐standing efforts to limit ecological damage inflicted by the invasive, parasitic sea lamprey (Petromyzon marinus). Habitat restoration and sea‐lamprey control create conflicting goals for managing aging infrastructure. We used optimization to minimize opportunity costs of habitat gains for 37 desirable migratory fishes that arose from restricting sea lamprey access (0–25% increase) when selecting barriers for removal under a limited budget (US$1–105 million). Imposing limits on sea lamprey habitat reduced gains in tributary access for desirable species by 15–50% relative to an unconstrained scenario. Additional investment to offset the effect of limiting sea‐lamprey access resulted in high opportunity costs for 30 of 37 species (e.g., an additional US$20–80 million for lake sturgeon [Acipenser fulvescens]) and often required ≥5% increase in sea‐lamprey access to identify barrier‐removal solutions adhering to the budget and limiting access. Narrowly distributed species exhibited the highest opportunity costs but benefited more at less cost when small increases in sea‐lamprey access were allowed. Our results illustrate the value of optimization in limiting opportunity costs when balancing invasion control against restoration benefits for diverse desirable species. Such trade‐off analyses are essential to the restoration of connectivity within fragmented rivers without unleashing invaders.  相似文献   
982.
Species reintroductions are increasingly used as means of mitigating biodiversity loss. Besides habitat quality at the site targeted for reintroduction, the choice of source population can be critical for success. The butterfly Melanargia russiae (Esper´s marbled white) was extirpated from Hungary over 100 years ago, and a reintroduction program has recently been approved. We used museum specimens of this butterfly, mitochondrial DNA data (mtDNA), endosymbiont screening, and climatic‐similarity analyses to determine which extant populations should be used for its reintroduction. The species displayed 2 main mtDNA lineages across its range: 1 restricted to Iberia and southern France (Iberian lineage) and another found throughout the rest of its range (Eurasian lineage). These 2 lineages possessed highly divergent wsp alleles of the bacterial endosymbiont Wolbachia. The century‐old Hungarian specimens represented an endemic haplotype belonging to the Eurasian lineage, differing by one mutation from the Balkan and eastern European populations. The Hungarian populations of M. russiae occurred in areas with a colder and drier climate relative to most sites with extant known populations. Our results suggest the populations used for reintroduction to Hungary should belong to the Eurasian lineage, preferably from eastern Ukraine (genetically close and living in areas with the highest climatic similarity). Materials stored in museum collections can provide unique opportunities to document historical genetic diversity and help direct conservation.  相似文献   
983.
In this study, indoor and outdoor radon (222Rn) surveys were carried out in the summer and winter seasons in homes of one hundred lung cancer patients in the year 2013–2014. The aim was to investigate the relationship between radon and cancer patients. Lung cancer patients completed a questionnaire concerning their living environment, various physical parameters and living habits. Pearson correlation and t tests revealed no meaningful results between radon concentrations, on one hand, and environmental and personal living habits, on the other hand. Consequently, the BEIR VI model was adapted and 222Rn exposure was estimated to be responsible for about 12% of the lung cancer incidences in the winter season and around 5% in the summer season in the Rize Province. However, due to the limited number of data and numerous parameters that could lead to lung cancer, the estimations done with the model should be taken very lightly. The annual effective doses due to inhalation of indoor and outdoor 222Rn were estimated to be, respectively, 1.43 and 0.94 mSv y?1. The indoor and outdoor annual effective doses were, respectively, close and below the world annual effective dose (1.3 mSv y?1). At the district level, the indoor annual effective dose equivalent in the ?yidere district was 4.52 mSv y?1, which was 3.5 times greater than the world average. The number of patients in the majority of the houses in this district was more than one.  相似文献   
984.
Climate change induces non-linear and unevenly distributed changes, such rising sea levels and extreme weather events that materialise on the regional level and considerably contribute to changes in the social fabric of regions, communities and places. Because of the need for societal responses, an in-depth understanding of individual and collective forms of engagement with climate change is of growing relevance. To contribute to close this gap, this paper applies a place-based approach for investigating how people’s place attachments and meanings inform individual and collective engagement with climate change. As a case study, the district of North Frisia (Germany) was chosen, a region between climate-change vulnerability and renewable-energy potential. Qualitative interviews and a household survey with coastal dwellers of the municipality of Reußenköge have been conducted, a group discussion with the Country Youth (Landjugend) and further interviews with experts from government, companies and associations spread over North Frisia and in Kiel. The results reveal two main findings: firstly, place-dependent attachments and meanings play a pivotal role for understanding people’s engagement with climate change, and secondly, the behavioural dimension of engagement involves diverse adaptation and mitigation measures adopted on individual and collective level. In sum, the findings conceptually and empirically reveal the importance of memories, experiences, knowledge and creativity for how people engage with climate change, but also exhibit the importance of policies mobilising community-based actions.  相似文献   
985.
After the deceleration of the postglacial marine transgression, the German North Sea coast was subject to deposition of a complex pattern of subtidal to terrestrial facies. This study aims at reconstructing these facies changes in the ‘Land Wursten’ region (Lower Saxony) by focussing on so-called dwog horizons (incipient soil horizons of the pre-engineered salt marshes). We explore their implications for relative sea-level reconstructions and their indication for early settlement activities. Archive drilling data (1960, provided by the ‘Landesamt für Bergbau, Energie und Geologie’) were analysed to create five high-resolution stratigraphic cross sections. Three new drilling records were subjected to sedimentological and microfaunal investigations and interpreted to verify and calibrate the archive data. Two dwog horizons were found and 14C-AMS dated. We found basal salt marsh deposits inundated by a high-energy event and covered by tidal flat sediments. The thick tidal flat unit is again overlain by salt marsh deposits indicating the transition from a shallow marine to a terrestrial environment where dwogs were developed and covered by episodic marine incursions. The ages of the dwogs (1128–969 cal BC; cal AD 1426–1467) do not correlate with known layers of adjacent settlement sites and are critically discussed. However, we show that they correlate with phases of stagnant regional relative sea level (RSL) and can be used as RSL indicators. The combined archive and modern data provide valuable information for the RSL reconstruction and palaeoenvironmental changes. However, further research is recommended to accomplish more detailed information about coastal response during the Holocene sea-level changes and implications for settlement dynamics.  相似文献   
986.
Spherical TiO2 nanoparticles (npTiO2) were prepared by controlled hydrolysis of tetraethoxy orthotitanate under a nitrogen atmosphere. ZnO nanoparticles (npZnO) were prepared using hydrothermal methods. The crystal structure, chemical, thermal and morphological properties of npZnO and npTiO2 were characterised using Fourier Transform Infrared Spectrometer, enery-dispersive X-ray spectroscopy, X-ray diffraction, and scanning electron microscope techniques. The short- and long-term experiments were started with neonates taken from the same culture and laboratory condition. In the acute experiments, npTiO2, npZnO, and cocktail concentrations were applied. 96h-LC50 values were 1.8, 0.7, and 0.1?mg?L?1, respectively (p?<?.05). For the chronic experiments, different npTiO2 concentrations were performed. 21d-LC50 value was 1.0?mgL?1 (p?<?.05). Morphometry became progressively worse in concentrations of more than 1?mgL?1 npTiO2. Neonate and young individuals were more sensitive to death because of their low tolerance. This result was affected by population progeny and growth rates (p?<?.05). While control and 0.5?mgL?1 npTiO2 groups were determined as growing population, 1.5 and 2?mgL?1 npTiO2 groups had decreased population size as R0 values. Consequently, the relationships between nanoparticle accumulation within Daphnia magna and its population structure and body morphometry for each concentration were important indicators. Its tolerance level to nanoparticles under laboratory conditions reflected its replacement and behaviour in the ecosystem.  相似文献   
987.
988.
To study the effect of flow velocity on drinking water distribution systems, bulk water quality was monitored over 28 days, biomass was measured, and 16S rDNA was sequenced on the 28th day using a water distribution simulation system. The relationship between bulk water quality and biofilm was statistically analyzed. Flow velocity of 0.5 m/s yielded the most total organic carbon (TOC) (5.26 ± 0.17 mg/L) in the bulk water, the most bulk water bacteria (lg (n+1/mL-1) = 4.79 ± 0.02), the worst bulk water quality, and the most biofilm bacteria (lg (n+1/cm-2) = 5.48 ± 0.06). A Pearson correlation analysis showed the total number of biofilm bacteria was positively correlated with conductivity (R = 0.73, P < 0.01), turbidity (R = 0.87, P < 0.001), TOC (R = 0.94, P < 0.001), and total bacteria (R = 0.92, P < 0.001), and was negatively correlated with residual chlorine (R = -0.68, P < 0.05). Biofilm diversity was high under the low (0.1 m/s) and high (2.5 m/s) flow rates, but the bacterial diversity of biofilm was the lowest at the 0.5 m/s flow rate, in which Proteobacteria dominated the biofilm community structure. These results suggest that flow velocity affects bulk water quality and biofilm population structure, and water quality and biofilm population structure are interrelated, which provides the theoretical basis for research on biofilms in drinking water distribution systems. © 2018 Science Press. All rights reserved.  相似文献   
989.
Tamarix is widely distributed in semiarid saline regions of the upper Yellow River. The community of Tamarix affects the spatial distribution of soil water and salinity. It is important to explore the dynamic response relationship of Tamarix community and spatial distribution of soil water and salinity in order to evaluate the effects of vegetation community construction and ecological restoration in this region. The natural Tamarix community in the secondary saline-alkali land of the Ningxia Yellow River Irrigation Area was investigated in July 2016. Classical statistics and geostatistics were used to analyze the spatial distribution characteristics of soil water and salinity. The results showed that the soil water content was relatively low (1.98%-7.55%), whereas the soil salinity was high (average conductivity 10.28-25.38 mS/cm) in the study area. The variability coefficient range of soil water and salinity was 36.1%-83.7%, both with moderate variations. Furthermore, the variation degree of soil salinity decreased with the increase in soil depth. The soil water and salinity had obvious spatial structure characteristics, which was mainly affected by structural factors or structural factors associated with stochastic factors. The coefficients of nugget were 0.04%-49.88%, indicating the strong spatial correlation. The spatial distribution of soil water and salinity in Tamarix community showed a patchy pattern; the soil water and salinity distribution in the areas with high Tamarix growing density were considerably high. The correlation analysis showed that there was a positive correlation between soil water and salinity in the study area. In conclusion, soil water and salinity restrict the distribution and growth of Tamarix. Furthermore, the distribution and growth of Tamarix enhanced the spatial variability of soil water and salinity. Keywords. © 2018 Science Press. All rights reserved.  相似文献   
990.
The European Union Guideline 2001/58/EG (safety data sheet guideline) states that the safety data sheet shall enable professional users to take the necessary measures for the protection of health and safety at the workplace as well as of the environment. According to this guideline, the employer should be in the position to determine whether hazardous chemical agents do exist at the workplace, and to assesses the risk to health and safety of workers arising from their use. Can the employer actually rely on the safety data sheet? Have the present data sheets really instructed how to safely handle and manage dangerous compounds? Are the numerously arising occupational illnesses by dangerous substances just a consequence of a careless handling? This question is also important in the discussion on REACH, the new European Chemicals Policy. This paper reveals the strengths and the weaknesses as well as the potential of manufacturer information.  相似文献   
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