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Search Results: 1 - 10 of 17949 matches for " Mark Leighton "
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The Impact of Land Use Change for Greenhouse Gas Inventories and State-Level Climate Mediation Policy: A GIS Methodology Applied to Connecticut  [PDF]
Linda Powers Tomasso, Mark Leighton
Journal of Environmental Protection (JEP) , 2014, DOI: 10.4236/jep.2014.517149
Abstract: Greenhouse gas (GHG) inventories conducted at state and regional levels serve to quantify long-term emissions trends and set benchmarks against which to evaluate the effectiveness of state government-mandated emissions reductions. GHG inventories which incompletely account for land use, land change, and forestry (LUCF) due to insufficient measurement tools discount the value of terrestrial carbon (C) sinks. In consequence, sink preservation is often omitted from regional land use planning. This paper proposes an accounting methodology which estimates foregone C sequestration derived LUCF change in the southern New England State of Connecticut (CT). The Natural Capital Project’s InVEST program provided a template for modeling C storage and sequestration for CT’s land class categories. LandSat mapping of long-term land cover patterns in CT conducted by CLEAR at the University of CT served as input data for InVEST computer modeling of C sequestration, both realized and foregone due to LUCF. The results showed that: 1) Land converted from high C density forestland to low density C land cover classes reduced the rate of C sequestration loss at 4.62 times the rate of forest reduction. Forest loss of 3.83% over twenty-five years was responsible for foregone C sequestration equivalent to 17.68% of total 2010 sequestration. 2) Accumulating C stocks pushed total annual sequestration from a 1985 baseline level of 866 MMTCO2 to 1116 MMTCO2 by 2010—a 250 MMTCO2 increment. 3) C sequestration from forest loss since 1985 would have yielded additional sequestration of 53.74 MMTCO2 by 2010. By 2002, foregone yield surpassed CT’s annual fossil fuel emissions, currently at 40 MMTCO2. 4) Preservation of forest C stocks over time becomes the determining factor for influencing biomass C sequestration levels. Deciduous forests have a preponderant influence on CO2 budgets. The ground-up methodology to quantify land-based C sequestration presented here demonstrates the influence of forest biomass in state-level C mitigation efforts useful to climate-oriented policy makers.
Update on the Pharmaceutical Industry
Leighton McDonald
Southern African Journal of HIV Medicine , 2004,
Abstract: The Sunday Times Business Times published a supplement on the pharmaceutical industry on 30 November 2003. This has been an extremely dynamic environment and one that will be affected by impending legislative change. The objective of the survey was to provide some insight into the current status of the industry – special attention was paid to costs of medication, generic medication and antiretroviral therapy. This article aims to provide a summary of the publication and provide background information where necessary. Southern African Journal of HIV Medicine Vol. 5 (1) 2004: 46-47
CIENCIA, VINO Y SALUD
F Leighton
Biological Research , 2004,
Abstract:
Polifenoles Vegetales, Ciencia y Bienestar
FEDERICO LEIGHTON
Biological Research , 2000,
Abstract:
Plant Polyphenol Antioxidants and Oxidative Stress
URQUIAGA,INES; LEIGHTON,FEDERICO;
Biological Research , 2000, DOI: 10.4067/S0716-97602000000200004
Abstract: in recent years there has been a remarkable increment in scientific articles dealing with oxidative stress. several reasons justify this trend: knowledge about reactive oxygen and nitrogen species metabolism; definition of markers for oxidative damage; evidence linking chronic diseases and oxidative stress; identification of flavonoids and other dietary polyphenol antioxidants present in plant foods as bioactive molecules; and data supporting the idea that health benefits associated with fruits, vegetables and red wine in the diet are probably linked to the polyphenol antioxidants they contain.in this review we examine some of the evidence linking chronic diseases and oxidative stress, the distribution and basic structure of plant polyphenol antioxidants, some biological effects of polyphenols, and data related to their bioavailability and the metabolic changes they undergo in the intestinal lumen and after absorption into the organism.finally, we consider some of the challenges that research in this area currently faces, with particular emphasis on the contributions made at the international symposium "biology and pathology of free radicals: plant and wine polyphenol antioxidants" held july 29-30, 1999, at the catholic university, santiago, chile and collected in this special issue of biological research
Plant Polyphenol Antioxidants and Oxidative Stress
INES URQUIAGA,FEDERICO LEIGHTON
Biological Research , 2000,
Abstract: In recent years there has been a remarkable increment in scientific articles dealing with oxidative stress. Several reasons justify this trend: knowledge about reactive oxygen and nitrogen species metabolism; definition of markers for oxidative damage; evidence linking chronic diseases and oxidative stress; identification of flavonoids and other dietary polyphenol antioxidants present in plant foods as bioactive molecules; and data supporting the idea that health benefits associated with fruits, vegetables and red wine in the diet are probably linked to the polyphenol antioxidants they contain.In this review we examine some of the evidence linking chronic diseases and oxidative stress, the distribution and basic structure of plant polyphenol antioxidants, some biological effects of polyphenols, and data related to their bioavailability and the metabolic changes they undergo in the intestinal lumen and after absorption into the organism.Finally, we consider some of the challenges that research in this area currently faces, with particular emphasis on the contributions made at the International Symposium "Biology and Pathology of Free Radicals: Plant and Wine Polyphenol Antioxidants" held July 29-30, 1999, at the Catholic University, Santiago, Chile and collected in this special issue of Biological Research
The Relative Effectiveness of Signaling Systems: Relying on External Items Reduces Signaling Accuracy while Leks Increase Accuracy
Gavin M. Leighton
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0091725
Abstract: Multiple evolutionary phenomena require individual animals to assess conspecifics based on behaviors, morphology, or both. Both behavior and morphology can provide information about individuals and are often used as signals to convey information about quality, motivation, or energetic output. In certain cases, conspecific receivers of this information must rank these signaling individuals based on specific traits. The efficacy of information transfer associated within a signal is likely related to the type of trait used to signal, though few studies have investigated the relative effectiveness of contrasting signaling systems. I present a set of models that represent a large portion of signaling systems and compare them in terms of the ability of receivers to rank signalers accurately. Receivers more accurately assess signalers if the signalers use traits that do not require non-food resources; similarly, receivers more accurately ranked signalers if all the signalers could be observed simultaneously, similar to leks. Surprisingly, I also found that receivers are only slightly better at ranking signaler effort if the effort results in a cumulative structure. This series of findings suggests that receivers may attend to specific traits because the traits provide more information relative to others; and similarly, these results may explain the preponderance of morphological and behavioral display signals.
Optimizing XML Compression
Gregory Leighton,Denilson Barbosa
Computer Science , 2009, DOI: 10.1007/978-3-642-03555-5_8
Abstract: The eXtensible Markup Language (XML) provides a powerful and flexible means of encoding and exchanging data. As it turns out, its main advantage as an encoding format (namely, its requirement that all open and close markup tags are present and properly balanced) yield also one of its main disadvantages: verbosity. XML-conscious compression techniques seek to overcome this drawback. Many of these techniques first separate XML structure from the document content, and then compress each independently. Further compression gains can be realized by identifying and compressing together document content that is highly similar, thereby amortizing the storage costs of auxiliary information required by the chosen compression algorithm. Additionally, the proper choice of compression algorithm is an important factor not only for the achievable compression gain, but also for access performance. Hence, choosing a compression configuration that optimizes compression gain requires one to determine (1) a partitioning strategy for document content, and (2) the best available compression algorithm to apply to each set within this partition. In this paper, we show that finding an optimal compression configuration with respect to compression gain is an NP-hard optimization problem. This problem remains intractable even if one considers a single compression algorithm for all content. We also describe an approximation algorithm for selecting a partitioning strategy for document content based on the branch-and-bound paradigm.
Unconditionally stable time splitting methods for the electrostatic analysis of solvated biomolecules
Leighton Wilson,Shan Zhao
Quantitative Biology , 2014,
Abstract: This work introduces novel unconditionally stable operator splitting methods for solving the time dependent nonlinear Poisson-Boltzmann (NPB) equation for the electrostatic analysis of solvated biomolecules. In a pseudo-transient continuation solution of the NPB equation, a long time integration is needed to reach the steady state. This calls for time stepping schemes that are stable and accurate for large time increments. The existing alternating direction implicit (ADI) methods for the NPB equation are known to be conditionally stable, although being fully implicit. To overcome this difficulty, we propose several new operator splitting schemes, in both multiplicative and additive styles, including locally one-dimensional (LOD) schemes and additive operator splitting (AOS) schemes. The proposed schemes become much more stable than the ADI methods, and some of them are indeed unconditionally stable in dealing with solvated proteins with source singularities and non-smooth solutions. Numerically, the orders of convergence in both space and time are found to be one. Nevertheless, the precision in calculating the electrostatic free energy is low, unless a small time increment is used. Further accuracy improvements are thus considered. After acceleration, the optimized LOD method can produce a reliable energy estimate by integrating for a small and fixed number of time steps. Since one only needs to solve a tridiagonal linear system in each independent one dimensional process, the overall computation is very efficient. The unconditionally stable LOD method scales linearly with respect to the number of atoms in the protein studies, and is over 20 times faster than the conditionally stable ADI methods.
Forest Fruit Production Is Higher on Sumatra Than on Borneo
Serge A. Wich, Erin R. Vogel, Michael D. Larsen, Gabriella Fredriksson, Mark Leighton, Carey P. Yeager, Francis Q. Brearley, Carel P. van Schaik, Andrew J. Marshall
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0021278
Abstract: Background Various studies have shown that the population densities of a number of forest vertebrates, such as orangutans, are higher on Sumatra than Borneo, and that several species exhibit smaller body sizes on Borneo than Sumatra and mainland Southeast Asia. It has been suggested that differences in forest fruit productivity between the islands can explain these patterns. Here we present a large-scale comparison of forest fruit production between the islands to test this hypothesis. Methodology/Principal Findings Data on fruit production were collated from Sumatran and Bornean sites. At six sites we assessed fruit production in three forest types: riverine, peat swamp and dryland forests. We compared fruit production using time-series models during different periods of overall fruit production and in different tree size classes. We examined overall island differences and differences specifically for fruiting period and tree size class. The results of these analyses indicate that overall the Sumatran forests are more productive than those on Borneo. This difference remains when each of the three forest types (dryland, riverine, and peat) are examined separately. The difference also holds over most tree sizes and fruiting periods. Conclusions/Significance Our results provide strong support for the hypothesis that forest fruit productivity is higher on Sumatra than Borneo. This difference is most likely the result of the overall younger and more volcanic soils on Sumatra than Borneo. These results contribute to our understanding of the determinants of faunal density and the evolution of body size on both islands.
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