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1.
The Cambro-Ordovician anomalocaridids are large ecdysozoans commonly regarded as ancestors of the arthropods and apex predators. Predation is indicated partly by the presence of an unusual “peytoia”-type oral cone, which is a tetraradial outer ring of 32 plates, four of which are enlarged and in perpendicular arrangement. This oral cone morphology was considered a highly consistent and defining characteristic of well-known Burgess Shale taxa. It is here shown that Anomalocaris has a different oral cone, with only three large plates and a variable number of smaller and medium plates. Its functional morphology suggests that suction, rather than biting, was used for food ingestion, and that anomalocaridids in general employed a range of different scavenging and predatory feeding strategies. Removing anomalocaridids from the position of highly specialized trilobite predators forces a reconsideration of the ecological structure of the earliest marine animal communities in the Cambrian.  相似文献   

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Farmers in rural Africa use a number of adaptive strategies to cope with observed climatic changes and their impacts on agriculture. Most studies on adaptive capacity focus on socio-economic parameters (such as poverty or education), and few provide detailed analysis on the role played by different institutions at local level, and the effects of how these institutions are perceived on farmers’ adaptation. Semi-structured interviews were conducted among 46 households from seven villages in southern Benin (West Africa), and among representatives of several institutions at the local level. Half the participants were involved in Non Governmental Organizations (NGOs) development projects and half were independent farmers. Results indicate that independent farmers mostly use non-agricultural coping strategies (loans, work in town) while project farmers mainly use agricultural adaptive strategies (improved seed varieties). Lack of adaptive capacity of independent farmers is linked to weak State institutions at the local level. Due to their lack of efficiency and high corruption rates, local State representatives are mistrusted. NGOs are trusted and seek for help, even by independent farmers. Even if NGOs do not have climate change adaptation in their agendas, they promote activities, which help reduce farmers’ vulnerability. Although our results are limited to south-western Benin, they question the way adaptation is promoted today, for instance through the United Nations Framework Convention for Climate Change (through the National Adaptation Programmes of Action).  相似文献   

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High genetic variability may increase metabolic efficiency and thus allows responding to environmental challenges as limits to adaptation are approached. Therefore, it has been suggested that high genetic variability contributes strongly to the fitness of an individual. Survival to high age may thus depend on high genetic variability, and genetically variable individuals may have a higher survival rate to high ages in comparison to less variable sympatric conspecifics. Such a heterozygosity × age relationship might be more readily detectable in stressful as compared to benign environments. For testing the relationship between age and heterozygosity, we genetically analyzed 71 individuals of the frog species Rana perezi from a total of seven populations at 13 allozyme loci. The age of the individuals was determined by skeletochronology. We found effects on age of both environment and allozyme heterozygosity, especially in populations with high stress regimes. A significant heterozygosity × age relationship has so far rarely been shown in natural populations. The result of our analysis suggests that more heterozygous individuals have a higher longevity and may be an important source of genetic variability of a population, likely contributing to a stabilization of the effective population size.  相似文献   

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The authors use β-phase pulmonary clearance data in conjunction with a pharmacokinetic model to estimate average background ambient level benzene exposure and resultant body burden. The pharmacokinetic model is also used to estimate the absorbed dose of benzene for cigarette smoking.  相似文献   

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China’s 2007 Open Government Information Regulations is widely considered as a milestone in the country’s information policy history and is praised as a “sunshine program”. The Environmental Information Disclosure Decree was the first to operationalize these general regulations into a sectoral information disclosure system on environment. This study assessed the implementation of the environmental information disclosure system about six months after the Decree took e ect on May 1, 2008. Through reviewing the websites of all 31 provincial Environmental Protection Bureaus and the Ministry of Environmental Protection, conducting an experiment with actual information disclosure request, and through interviews with all provincial Environmental Protection Bureaus, this article concluded that the implementation of the environmental information disclosure system still falls short. Future improvements should focus on further publicity of the regulations and decree to enhance public participation, the establishment of an independent evaluation and supervision system for information disclosure, the exchange of experiences and best practices among provincial Environmental Protection Bureaus, and on strengthening the legal status of environmental information disclosure.  相似文献   

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The study provides insight into the combined effect of sorbent surface functionalities and microporosity on2,2 ′,4,4 ′-tetrabromodiphenyl ether (BDE-47) sorption onto biochars. A series of biochars prepared underdifferent conditionswere used to test their sorption behaviorswith BDE-47. The extents of sorption behaviorswere parameterized in terms of the single-point adsorption equilibrium constant (Koc ) at three equilibrium concentration (C e ) levels (0.001Sw (solubility), 0.005Sw , and 0.05Sw )whichwasdetermined using the Freundlich model. To elucidate the concentration-dependentdominant mechanisms for BDE-47 sorption onto biochars, K ocwas correlatedwith four major parameters using multiple parameter linear analysis accompaniedwith significance testing. The results indicated that at low concentration (Ce = 0.001Sw ), the surface microporosity term,which represented a pore-filling mechanism, contributed significantly to this relationship,while as concentrationwas increased to higher levels, surface functionality related to surface adsorption began to take thedominant role,whichwas further confirmed by the results of Polanyi-based modeling. Given the above results, adual mode model based on Dubinin-Radushkevich andde Boer-Zwikker equationswas adopted to quantitatively assess the changes of significance of surface adsorption aswell as that of pore fillingwith sorption processdevelopment. In addition, UV spectra of four typical aromatic compoundswhich represented the key structural fragments of biochars before and after interactionswith BDE-47were analyzed todetermine the active functional groups and supply complementary evidence for thedominant interaction force for surface adsorption, based onwhich π-π electron-donor-acceptor interactionwas proposed to contribute greatly to surface adsorption.  相似文献   

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Although it is common practice for resource managers to focus on processes by which human activity in the environment may be adapted to ensure the sustainability of natural ecosystems, we often forget that our perceptions of who we are given where we live greatly influence the political context for regional ecosystem management. These shared ‘senses of selves-in-place’ serve as potent mediators in the process of attending to or embracing conservation-oriented practices. The authors argue that citizens’ senses of selves-in-place form the major link between how people appraise communication appeals and how they behave in the environment. Discussion focuses on the significance of the association between a sense of place, how the self gets related to the environment, and sense making related to conservation-oriented advocacy. Past and contemporary empirical studies reveal various elements of the sense of self-in-place construct. In turn, the analysis focuses on the tension that often develops given the desires of local stakeholders in competition with land-use advocates from afar (e.g. industrialists, nongovernmental organizations) by exploring three case studies of regional natural resource conflicts. Conclusions address how a sense of self-in-place analysis could be incorporated into and add value to ongoing natural resource management efforts.  相似文献   

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Aerosol leads to 30% reduction in solar radiation reaching the earth’s surface, and a similar reduction in crops yield for both wheat and rice. To determine the effect of aerosol wet deposition on crops, aerosol samples were collected in September, 2006 at Xi’an urban suburb (34?44 N, 109?49 E), and wheat seedlings were treated with aerosol of different concentrations in laboratory conditions. Changes in physiological and biochemical parameters of wheat seedlings were measured. In comparison with the control, the activities of superoxide dismudase (SOD) and catalase (CAT) and the concentration malondialdehyde (MDA) and oxidized glutathione (GSSG) of wheat seedlings increased progressively with increasing concentrations of added aerosol, while the opposite trend was seen for the activities of nitric oxide synthase (NOS), the concentrations of glutathione (GSH) and nitric oxide (NO), and the ratio of GSH/GSSG. When the seedlings were treated with the aerosol of 1 and 2 mg/L, the coleoptile elongation, shoot elongation and biomass accumulation were increased, the effect at treatment of 2 mg/L was most significant. However, aerosol treatments with rates of 3 and 4 mg/L resulted in a decrease in coleoptile elongation, shoot elongation and biomass accumulation in seedlings, and significant effect was for the treatment of 4 mg/L. Hence, lower concentrations of aerosol wet deposition were in favor of crops growth, but its higher concentrations could result in deleterious effects for crops and decreased crops growth.  相似文献   

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In 1968, excavations in the Climente II cave in the Iron Gates gorge of the River Danube in southwest Romania unearthed the skeleton of an adult male. The burial was assumed to be of Late Pleistocene age because of the presence of Late Upper Palaeolithic (LUP) artefacts in the cave. However, there was no strong supporting stratigraphic evidence, and the body position is reminiscent of Early Neolithic burial practice in the region. Here, we report the results of radiocarbon and stable isotope analyses of the Climente II skeleton, which show that the skeleton dates to the Bølling–Allerød Interstadial ~14,500 cal BP. This is several millennia older than any previously dated human remains from the Iron Gates region and confirms its status as the oldest known burial from Romania. The stable isotope results indicate a diet with an emphasis on aquatic resources, contrary to the commonly held view that the LUP inhabitants of the Iron Gates subsisted mainly by hunting large land mammals.  相似文献   

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Increasingly, Native American and non-Native governments, institutions and individuals are searching for cooperative ways to address environmental problems. While such approaches can offer substantial benefits over top-down or unilateral efforts, there are also potential pitfalls, especially when considering the needs and interests of the Native parties. Among these are threats to their status as sovereign nations, and to their political, economic and cultural autonomy. Given such concerns, many Indian Nations are seeking models for collaboration which protect their unique status based on indigenous and treaty rights, while respecting their cultural identity, values, and indigenous knowledge. In this paper we explore how one Native group in particular, a coalition of Haudenosaunee Nations in the US and Canada, has dealt with these complex issues. We show how positive relationships with outside agencies and researchers have been made possible through the use of mechanisms and processes based on traditional Haudenosaunee concepts and values. Finally, we explore how one item in particular, a 17th century treaty belt called the Kaswentha, offers a powerful symbol for forming relationships which respect Haudenosaunee autonomy while allowing collaborative partnerships to address critical environmental concerns.  相似文献   

13.
Reversible double water in oil in water (W/O/W) emulsions were developed to contain subsurface hydrocarbon spills during their remediation using surfactant flushing. Double emulsions were prepared by emulsifying CaCl2 solutions in canola oil, and subsequently by emulsifying the W/O emulsions in aqueous sodium alginate solutions. The formation of double emulsions was confirmed with confocal and optical microscopy. The double emulsions reversed and gelled when mixed with the surfactants sodium dodecyl sulfate (SDS) and cocamidopropyl betaine (CPB). Gels can act as ‘emulsion locks’ to prevent spreading of the hydrocarbon plume from the areas treated with surfactant flushing, as shown in sand column tests. Shear rheology was used to quantify the viscoelastic moduli increase (gelation) upon mixing the double emulsion with SDS and CPB. SDS was more effective than CPB in gelling the double emulsions. CPB and SDS could adsorb at the interface between water and model hydrocarbons (toluene and motor oil), lowering the interfacial tension and rigidifying the interface (as shown with a Langmuir trough). Bottle tests and optical microscopy showed that SDS and CPB produced W/O and O/W emulsions, with either toluene or motor oil and water. The emulsification of motor oil and toluene in water with SDS and CPB facilitated their flow through sand columns and their recovery. Toluene recovery from sand columns was quantitated using Gas-Chromatography Mass-Spectroscopy (GC-MS). The data show that SDS and CPB can be used both for surfactant flushing and to trigger the gelation of ‘emulsion locks’. Ethanol also gelled the emulsions at 100 mL/L.  相似文献   

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The risks related to global climate change are seen as threats to companies, taking into consideration their impact on the return on investment. In order to mitigate climate risk and introduce new opportunities to financiers, companies need to identify, manage, and report climate risks. The purpose of this paper is to investigate the climate risks disclosed by the 100 largest companies in the world, according to the Bloomberg and Price Waterhouse Coopers (PwC 2015) classification, and identify some characteristics of these companies that explain the disclosure level of such information. Preliminary results revealed that of the companies investigated, 14% did not disclose any climate risk information in the Carbon Disclosure Program (CDP) report. Also, from the companies that disclosed information according to the Global Reporting Initiative (GRI), 9.9% did not provide information regarding policies, actions, and strategies for mitigating the risks related to climate change. The results shown by the content analysis suggested that, in general, there is still a low level of disclosure about climate risks by these companies. The final results through econometric instruments and statistical tests indicate that the size of the company or the fact that corporations are from developed countries do not necessarily explain the level of information disclosed. However, the activity sector, the continent, and the efficiency of the Board of Directors are factors that strongly explain the level of climate risk disclosure. We conclude that more effort is needed to encourage an engaging attitude from corporations to develop actions, policies, and strategies to mitigate climate change risks and threats. In addition, the world’s largest companies should make a greater investment in climate risk disclosure.  相似文献   

16.
A proactive strategy to respond effectively to health impacts related to climate variability, particularly within vulnerable populations, is of vital importance. Such a strategy can be attained if health officials have a deep understanding of how climate variability affects human health and if the resources available for the health care sector are sufficient. This study assessed the perceptions and preparedness of health officials toward climate variability and health impacts in the Somali region of Ethiopia. The resources available for the health care sector were also assessed. The results show that approximately 80% of health officials were aware of the relationship between climate variability and human health impacts, but the majority of them were unable to project the future trend of related health problems in the region. The results also show an inadequate availability of health care resources, particularly in regards to infrastructure, numbers of health professionals, and training on climate variability and health. The results further revealed problems with poor living conditions, such as access to sanitation and safe water, for the majority of people in the study area. Climate variability is thus one of the many factors exacerbating the increasing trend of human health problems in the Somali region. Besides improving training to increase health officials’ knowledge of climate variability and human health impacts, the government should also address other factors that currently hinder a successful response to increasing disease prevalence.  相似文献   

17.
This paper examines significant and unjustifiable differences arising under the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA, Pub. L. No. 96-510, 94 Stat. at Large 2767, codified as amended at 42 USC §§ 9601-9675) in the way in which the Superfund may be used to remediate "orphaned" National Priorities List (NPL) sites and "orphaned" brownfield sites. Under both the existing law and numerous proposals for the reauthorization of CERCLA, while the Superfund may be used for the remediation of orphaned NPL sites, it may not be used for the remediation of orphaned brownfield sites. In each situation, however, an absent, insolvent, defunct, bankrupt or judgment-proof party has created a situation in which remediation costs must be borne by the public. The study concludes that there is no fundamental policy reason for treating these orphans differently and presents recommendations to facilitate the remediation and redevelopment of both NPL sites and brownfield sites.  相似文献   

18.
An appropriate system of laws and regulations and a suitable institutional structure for administration are important requirements for the effective management of small-scale mines. Over the last twenty years, township and village coal mines in China have made a large contribution to the country’s supply of energy. Yet at the same time they have had substantial negative impacts, such as wastage of coal resources, a high casualty rate amongst miners, and a wide range of environmental damage. Two reasons for the magnitude of these externalities are the highly complex nature of the institutional structure for regulating small-scale coal mines, and the excessive and incoherent burden of applicable laws and regulations.  相似文献   

19.
It is thought that young homing pigeons are able to use information acquired en route for their initial homeward orientation. However, the cues involved and mechanisms utilised are under discussion. Blocking light-dependent route-specific information during the first leg of an outward journey detour, together with analysis of pigeons that were raised under different loft conditions, allowed us to correctly evaluate the functioning of this mechanism and, more generally, the navigational map of birds. Pigeons from the same stock were raised and kept in two different lofts. The birds in the experimental groups were transported to the release sites via detours, and light-dependent information was denied during the first half of the outward journey (no compass information was available). Control birds were transported by the most direct route and had access to all available information. In general, the results showed that the low-loft birds preferred to use magnetic compass cues, whereas the high-loft birds preferred to use navigational map cues to collect information of the first part of the outward journey. The impairments observed in the homing performances of the experimental groups highlight the reliability of information collected inside the map area. Relevant to an understanding of the route-reversal mechanism was the evidence that this mechanism is able to function in the absence of compass information (birds raised in a wind-exposed loft show a detour effect). In systems where directional information could be provided by multiple sources, processing and extracting accurate course trajectories through a common mechanism may prove more efficient and reliable.  相似文献   

20.
Predation is an unavoidable and dangerous fact in the lifetime of prey animals and some sign of the proximity of a predator may be enough to trigger a response in the prey. We investigated whether different degrees of predation risk by red foxes (Vulpes vulpes) evoke behavioural and physiological stress responses in wood mice (Apodemus sylvaticus). We examined the variation in mice responses due to individual factors (sex and reproductive status) and related them to the concentration of the volatile compounds from fox faeces over time. In our experiment, we introduced predation cues into four plots, each subjected to a different concentration treatment (0, 10, 50 and 100% concentration of fresh faeces of red fox), based on the following outline: initial odourless phase 0, phase1 in which predation treatment was renewed daily, and phase 2 in which we renewed the treatment only on the first day. Wood mice were live trapped during all three phases and the physiological response was measured non-invasively by analysing faecal corticosterone metabolites (FCM) in freshly collected faeces. Data were analysed by Generalized Linear Mixed Models. Overall, males were trapped less often than females, and reproductively active individuals from both sexes avoided traps more than non-reproductively active individuals, especially in medium- and high- concentration plots. Variations in FCM concentrations were explained by plot, the interaction between plot and treatment phase, and the interaction between the treatment phase and the reproductive status. During phase 1, we detected a significant rise in FCM levels that increased with predator faecal odour concentration. Additionally, reproductively active individuals showed a strong physiological response during both phases 1 and 2 in all plots, except the control plot. Our results indicated that wood mice are able to discriminate different degrees of predation risk, which allows them to trigger gradual changes in their behavioural and physiological stress responses.  相似文献   

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