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471.
The controversial family Adapisoriculidae, a group of shrew-sized Paleocene mammals, had proposed relationships with insectivores,
marsupials and more recently to plesiadapiforms. Adapisoriculid remains are numerous in the early Paleocene locality of Hainin,
Belgium, and allow us a test of these different phylogenetic hypotheses. Here, we identify the first tarsal bones of adapisoriculid
mammals. The highly specialised bones indicate an arboreal mode of life with euarchontan affinity. Moreover, the tarsal bones
are morphologically very close to those of the late Cretaceous Deccanolestes from the Deccan intertrappean beds of India, and also share several characters with the Paleocene plesiadapiforms and the
extant cynocephalid dermopterans. The adapisoriculid affinities of Deccanolestes are also confirmed by tooth morphology, indicating that Deccanolestes is a primitive member of this family. These phylogenetic affinities suggest a paleobiogeographic scenario for the family
with dispersal either via East Africa or across the Tethys area. 相似文献
472.
Eduardo A. Pedace Eric B. Sansone 《Journal of the Air & Waste Management Association (1995)》2013,63(5):348-351
Experimental relationships between the mass concentration of suspended particulate matter and the optical density of particulates collected on paper tape have been determined for the atmospheric aerosol and for aerosols of constant optical properties. Simultaneous samples were obtained on membrane filters (for gravimetric analysis) and on Whatman No. 4 paper tape (for optical evaluation). Sampling procedures were adopted which ensured that the efficiency of sampling was the same in both cases. Consistent relationships between mass concentrations of suspended particulate matter and optical density expressed in terms of per cent transmittance or per cent reflectance were found for dispersions of coal, limestone, fly ash, and a coal-limestone mixture. For atmospheric aerosol samples collected on the roof of the Graduate School of Public Health, University of Pittsburgh, the relationship between mass concentration and per cent transmittance or per cent reflectance was found to be linear over the range of values observed. The correlation coefficients were ?0.93 (for concentration versus per cent transmittance) and ?0.89 (for concentration versus per cent reflectance). 相似文献
473.
Eric Tabacchi Anne‐Marie Planty Tabacchi 《Journal of the American Water Resources Association》2001,37(6):1629-1637
ABSTRACT: This paper analyzes the spatial patterns of plant species richness observed in 1989 and in 1999 alongside the Adour River (Southwest France), focussing on: (1) upstream‐to‐down‐stream changes, (2) mid‐term changes, and (3) differences in observed patterns among various plant functional groups. The purpose of the research was to analyze how the proportions of invading species and/or ruderal species within riparian corridors can be related to regional environmental settings. About half of native and exotic species were ruderals. However, the proportion of competitors was higher within the native pool. No correlation was found between exotic and native functional groups. The longitudinal distribution of native and exotic ruderal species were correlated together, but they were not correlated with the total species richness. Converse to observations at the local scale in other studies, these patterns seem to be driven more by factors co‐varying with the size of the river and by climatic factors than by hydrological disturbance‐related factors. The role of the various plant groups studied and potential consequences on ecosystem function are discussed in the context of an increasing susceptibility of our ripanan corridors to invasions by nonriparian species. Management perspectives are discussed for the purpose of biodiversity conservation. 相似文献
474.
Peggy A. Johnson Eric R. Brown 《Journal of the American Water Resources Association》2001,37(5):1225-1236
ABSTRACT: The designs of stream channel naturalization, rehabilitation, and restoration projects are inherently fraught with uncertainty. Although a systematic approach to design can be described, the likelihood of success or failure of the design is unknown due to uncertainties within the design and implementation process. In this paper, a method for incorporating uncertainty in decision‐making during the design phase is presented that uses a decision analysis method known as Failure Modes and Effects Analysis (FMEA). The approach is applied to a channel rehabilitation project in north‐central Pennsylvania. FMEA considers risk in terms of the likelihood of a component failure, the consequences of failure, and the level of difficulty required to detect failure. Ratings developed as part of the FMEA can provide justification for decision making in determining design components that require particular attention to prevent failure of the project and the appropriate compensating actions to be taken. 相似文献
475.
Wen Yinghao Lichtfouse Eric Sharma Virender K. Ma Xingmao 《Environmental Chemistry Letters》2023,21(1):15-20
Environmental Chemistry Letters - The persistence of recalcitrant pollutants in water is a major health issue calling for advanced and green techniques to clean polluted waters. For instance,... 相似文献
476.
Verónica P. Martino Eric Pollet Luc Avérous 《Journal of Polymers and the Environment》2011,19(4):819-826
The swelling capability of chitosan was explored in order to use water both, as volatile plasticizer and as pore-forming agent.
Chitosan powder was swelled in acidic aqueous solution and melt blended with poly(ε-caprolactone) (PCL). After stabilization
at 57% RH and 25 °C, samples suffered a water mass loss of around 30 wt% without dimensions variation. Despite the low miscibility
of these biopolymers, quite homogeneous dispersion of chitosan within the polyester matrix was obtained. Some interactions
between both biopolymers could be observed. To obtain chitosan phase with a thermoplastic-like behaviour, the plasticization
effect was also studied by the addition of 25 wt% glycerol as non volatile plasticizer. The equilibrium moisture content of
samples increased with the incorporation of glycerol due to its hydrophilic nature. Morphology, thermal and mechanical properties
of the blends were determined after stabilization. The preparation of rich PCL blends allowed the formation of macroporous
structures since samples were not contracted after water loss and stabilization. These biomaterials with such a porous structure
could be used for biomedical applications. 相似文献
477.
This article provides a case-study of variability in children's independent access to their local environments in the New Zealand city of Christchurch. It is based on research with children in middle childhood, parents and teachers in four schools in Christchurch, each selected on the basis of variables hypothesised to impact on children's access to their local areas. The paper outlines why such independent access is of value, not only for children, but also for adults responsible for their safety, for the wider environment and for the local community. Variability within Christchurch is related to the socio-spatial nature of local environments. International comparisons are also made, drawing out the implications of differing cultural contexts for the pursuit of child-friendly cities. The article explores the role of social traps in impeding the creation of a more sustainable, child-friendly city. 相似文献
478.
Eric de Noronha Vaz Agnieszka Walczynska Peter Nijkamp 《Regional Environmental Change》2013,13(1):33-42
Coastal change and coastal erosion have been a long-existing source of environmental changes. Traditionally, regional changes in wetland systems and their relations to agriculture, industry and urbanization are a major cause for concern. Nowadays, coastal distress has reached even global proportions: the problems of coastal change are strongly linked to the loss of fragile ecosystems, eutrophication and loss of biodiversity. Given that over 70 % of all human activity is in coastal areas, it is clear that many environmental and socio-economic changes occur at a local level and manifest themselves in a spatial context. The physical effect on the geographic morphology is evident in the related consequences for land use. A deep understanding of the changes in land use, and simultaneously in coastal erosion, calls for the integrated monitoring of the most relevant effects in fragile regions. The Ria Formosa wetland system is a unique and very special wetland system in the Algarve (Portugal) and has been integrated in the NATURA 2000 network. The strong symbiosis between nature, agriculture and fisheries, as well as tourism, in the Algarve has led to spatial-ecological synergy. By using coastal recession analysis techniques by means of remote-sensed imagery from 1987, 1989, 2000 and 2007 and by combining this information with available data sets on surface erodibility, a cost surface on multitemporal transitions of land-use classes from the CORINE Land Cover data allows us to assess and integrate a decision-making framework by means of GIS. The novelty of this combined approach to land-use management is the blend of spatial analysis and remote-sensing techniques that share important information on ecosystems at risk. Our findings suggest a growing concern to the area brought by anthropogenic activity. This is studied to a spatial accounting of the distribution of land changes and transitions, where (1) a significant loss of coastal area is witnessed along the Ria Formosa, leading in particular to loss of agricultural land. (2) This loss is underpinned by an increase in leisure facilities to respond to the tourism demand of the region of the Algarve, while landscape metrics suggest that these areas are more volatile for coastal erosion. (3) Simulation through Markov chains on the land use and effects of urban, agricultural, forest and wetland dynamics suggests that by 2026, it is expected to continue to have an increase in urban land, leading to an augmented vulnerability of coastal erosion processes brought by the loss of forest areas which protect from erosion given the root system that directly protects from the existing wave energy and helps sedimentation processes. The above methodology and the availability of data that are freely available render such a combined approach interesting for many other regions of the world, where tourism, coastal change and regional balance are of the utmost importance for sustainable development. The advanced research tools presented here are of critical importance for coastal zone degradation management. 相似文献
479.
The recognition that resilience is a critical aspect of infrastructure security has caused the national and homeland security communities to ask “How does one ensure infrastructure resilience?” Previous network resilience analysis methods have generally focused on either pre-disruption prevention investments or post-disruption recovery strategies. This paper expands on those methods by introducing a stochastic optimization model for designing network infrastructure resilience that simultaneously considers pre- and post-disruption activities. The model seeks investment–recovery combinations that minimize the overall cost to a distribution network across a set of disruption scenarios. A set of numerical experiments illustrates how changes to disruption scenarios probabilities affect the optimal resilient design investments. 相似文献
480.
Infrastructure resilience has become a primary objective for homeland and national security organizations over the past decade. Recent initiatives have focused on resilient building design, and one approach under consideration is a voluntary resilience certification program for commercial buildings. The intent of this program would be to encourage the adoption of resilient design practices in construction and planning of the buildings. While resilience may be a frequently discussed concept within the security communities, its level of awareness within the construction, design, insurance, and building owner communities is not well known. Given the voluntary nature of the certification program under consideration, program development requires a comprehensive understanding of resilience as defined by the commercial building stakeholders. Toward this end, Sandia National Laboratories conducted a study of stakeholder perspectives on resilience to ascertain factors that would serve as motivation for participation in the resilience certification program. This paper describes how Sandia performed the study and the resulting conclusions. One of the key conclusions that the study found is that the term resilience is unfamiliar to many and inconsistently defined across the industries. Those familiar with the term frequently linked it to sustainability concepts. The study also found that increased participation in the resilience certification program is very likely affected by demonstrable returns on resilience investments and a public–private partnership model for program administration. 相似文献