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Possible Loss (possible + loss)
Selected AbstractsTesting for criticality in ecosystem dynamics: the case of Amazonian rainforest and savanna fireECOLOGY LETTERS, Issue 7 2010Salvador Pueyo Ecology Letters (2010) 13: 793,802 Abstract We test for two critical phenomena in Amazonian ecosystems: self-organized criticality (SOC) and critical transitions. SOC is often presented in the complex systems literature as a general explanation for scale invariance in nature. In particular, this mechanism is claimed to underlie the macroscopic structure and dynamics of terrestrial ecosystems. These would be inextricably linked to the action of fire, which is conceived as an endogenous ecological process. We show that Amazonian savanna fires display the scale-invariant features characteristic of SOC but do not display SOC. The same is true in Amazonian rainforests subject to moderate drought. These findings prove that there are other causes of scale invariance in ecosystems. In contrast, we do find evidence of a critical transition to a megafire regime under extreme drought in rainforests; this phenomenon is likely to determine the time scale of a possible loss of Amazonian rainforest caused by climate change. [source] Optimal use of high-resolution topographic data in flood inundation modelsHYDROLOGICAL PROCESSES, Issue 3 2003P. D. Bates Abstract In this paper we explore the optimum assimilation of high-resolution data into numerical models using the example of topographic data provision for flood inundation simulation. First, we explore problems with current assimilation methods in which numerical grids are generated independent of topography. These include possible loss of significant length scales of topographic information, poor representation of the original surface and data redundancy. These are resolved through the development of a processing chain consisting of: (i) assessment of significant length scales of variation in the input data sets; (ii) determination of significant points within the data set; (iii) translation of these into a conforming model discretization that preserves solution quality for a given numerical solver; and (iv) incorporation of otherwise redundant sub-grid data into the model in a computationally efficient manner. This processing chain is used to develop an optimal finite element discretization for a 12 km reach of the River Stour in Dorset, UK, for which a high-resolution topographic data set derived from airborne laser altimetry (LiDAR) was available. For this reach, three simulations of a 1 in 4 year flood event were conducted: a control simulation with a mesh developed independent of topography, a simulation with a topographically optimum mesh, and a further simulation with the topographically optimum mesh incorporating the sub-grid topographic data within a correction algorithm for dynamic wetting and drying in fixed grid models. The topographically optimum model is shown to represent better the ,raw' topographic data set and that differences between this surface and the control are hydraulically significant. Incorporation of sub-grid topographic data has a less marked impact than getting the explicit hydraulic calculation correct, but still leads to important differences in model behaviour. The paper highlights the need for better validation data capable of discriminating between these competing approaches and begins to indicate what the characteristics of such a data set should be. More generally, the techniques developed here should prove useful for any data set where the resolution exceeds that of the model in which it is to be used. Copyright © 2002 John Wiley & Sons, Ltd. [source] Association between blood flow and inflammatory state in a T-cell transfer model of inflammatory bowel disease in miceINFLAMMATORY BOWEL DISEASES, Issue 5 2010Norman R. Harris PhD Abstract Background: Adoptive transfer of naive T-lymphocyte subsets into lymphopenic mice initiates chronic gut inflammation that mimics several aspects of inflammatory bowel disease (IBD). Patients with IBD can have profound alterations in intestinal blood flow, but whether the same is true in the T-cell transfer model has yet to be determined. Methods: In the current study, chronic intestinal inflammation was induced in recombinase-activating gene-1-deficient (RAG,/,) mice by adoptive transfer of CD4+ T-lymphocytes obtained from interleukin-10 deficient (IL-10,/,) mice. Results: Four weeks later, widespread colonic inflammation was observed in the reconstituted recipients, in contrast to 2 control sets of mice injected with a different subset of lymphocytes or with vehicle alone. We observed that the resulting pathology induced in the reconstituted RAG,/, mice was divided distinctly into 2 subsets: 1 with blood flow near normal with very high inflammation scores, and the other with severely attenuated blood flow but with much lower signs of inflammation. Colonic and ileal blood flow rates in the latter subset of CD4+ mice averaged only ,30% compared to the mice with higher inflammation scores. The lower blood flow rates were associated with greatly reduced red blood cell concentrations in the tissue, suggesting a possible loss of vascular density. Conclusions: In this model of chronic intestinal inflammation, mild inflammation was associated with significant decreases in blood flow. Inflamm Bowel Dis 2009 [source] Transcoding media for bandwidth constrained mobile devicesINTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 2 2005Kevin Curran Bandwidth is an important consideration when dealing with streaming media. More bandwidth is required for complex data such as video as opposed to a simple audio file. When delivering streaming media, sufficient bandwidth is required to achieve an acceptable level of performance. If the information streamed exceeds the bandwidth capacity of the client the result will be ,choppy' and incomplete with possible loss of transmission. Transcoding typically refers to the adaptation of streaming content. Typical transcoding scenarios exploit content-negotiation to negotiate between different formats in order to obtain the most optimal combination of requested quality and available resources. It is possible to transcode media to a lesser quality or size upon encountering adverse bandwidth conditions. This can be accomplished without the need to encode multiple versions of the same file at differing quality levels. This study investigates the capability of transcoding for coping with restrictions in client devices. In addition, the properties of transcoded media files are examined and evaluated to determine their applicability for streaming in relation to a range of broad device types capable of receiving streaming media.,Copyright © 2005 John Wiley & Sons, Ltd. [source] Risk as a Window to Agency: A Case Study of Three DecoratorsJOURNAL OF INTERIOR DESIGN, Issue 1 2008Nancy H. Blossom M.A. ABSTRACT This paper explores the idea of "risk" by examining the role of three women in interior design in the twentieth century (Elsie de Wolfe, 1865,1950; Dorothy Draper, 1888,1969; and Sister Parish, 1929,1994). Women's roles as arbiters of taste were consistent with the social construction of the female gender at the turn of the century; that these roles involved risk,the perception of possible loss or injury,is, for the most part, overlooked by social historians. Our theoretical framework is built upon three keywords from the vocabularies of postmodern social history and women's history: discourse, experience, and agency. These three terms represent the important recognition that the collective understanding of history is not static, but is dependent on the social constructs of the period, as well as (1) how individuals experienced, interpreted, and acted within these constructs and (2) how historians understand and interpret the individual actions in the context of the same constructs. These concepts suggest that individual characters have agency (i.e., power or choice) in framing or reframing an event, based on their unique view of the world. It is through agency that we explore unique qualities of de Wolfe, Draper, and Parish. The stories of de Wolfe, Draper, and Parish demonstrate that risk of traditional values, risk of public persona, and risk of financial security all influenced the ways that they navigated the social and economic circumstances that surrounded them. Each risk, whether imposed on or undertaken by our protagonists, was a seed of change that ultimately affected the social and professional construct of the field of interior design. [source] Impact of improved phosphite hydrolytic stability on the processing stabilization of polypropyleneJOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 4 2005Brian Johnson It is well known that some high-performance phosphite antioxidants are particularly sensitive to hydrolysis. This process has two principal consequences: 1) the creation of potential handling issues, as the product can become sticky, and 2) a possible loss in the performance of this type of antioxidant. In this article both of these are addressed. First, changes in the hydrolytic stability of a high-performance phosphite are examined by formulating with co-additives of different chemical natures. Second, changes in the hydrolytic stability of the phosphite when using different additive physical forms are investigated. Third, the influence of hydrolysis on the processing stabilization performance of the high-performance phosphite is evaluated. It is seen that the rate of hydrolysis of the high-performance phosphite is drastically reduced both by altering the physical form of the additive package and by the correct selection of the co-additive package. This selection not only extends the storage life of the high-performance phosphite but also minimizes the risk of any handling issues. Furthermore, it is concluded that hydrolysis does not necessarily mean a loss in performance but, contrary to general perception, can actually lead to an enhancement of the processing stability. The final conclusion of this study is that the hydrolysis mechanism of the phosphite is strongly influenced by the physical form of the additive package and by the chemical nature of the co-additives. This difference in mechanism is responsible for a different level of processing performance but is not discussed in detail in this publication. J. VINYL. ADDIT. TECHNOL. 11:136,142, 2005. © 2005 Society of Plastics Engineers. [source] Probabilistic risk modeling at the wildland urban interface: the 2003 Cedar FireENVIRONMETRICS, Issue 6 2009D. R. Brillinger Abstract The October 2003 Cedar Fire in San Diego County was a tragedy involving 15 deaths, the burning of some 280,000,acres of land, the destruction of approximately 2227 homes, and costs of suppression near $30 million. It was the largest fire in California history. The data associated with the fire, however, do provide an opportunity to carry out probabilistic risk modeling of a wildland-urban interface (WUI) event. WUI's exist where humans and their development interface with wildland fuel. As home building expands from urban areas to nearby forest areas, these homes become more likely to burn. Wildfires are an exceedingly complex phenomenon with uncertainty and unpredictability abounding, hence a statistical approach to gaining insight appears useful. In this research, spatial stochastic models are developed. These relate risk probabilities and losses measures to a variety of available explanatory quantities. There is a consideration of economic aspects and a discussion of the difficulties that arose in developing the data and of carrying out the analyses. Purposes of the work include highlighting a statistical method, developing variates associated with a destruction probability and employing the fitted risk probability to estimate future and possible losses. Copyright © 2008 John Wiley & Sons, Ltd. [source] | ||||||||||