521 research outputs found
The Geology and Deformation History of the Southern Part of the Matapedia Zone and Its Relationship to the Miramichi Zone and Canterbury Basin
Guidebook to the geology of Northeastern Maine and neighboring New Brunswick: The 72nd annual meeting of the New England Intercollegiate Geological Conference, Presque Isle, Maine, October 10-13, 1980: Trip B-1
The influence of African air pollution on regional and global tropospheric chemistry
International audienceWe investigate the relative importance of African biomass burning, biogenic volatile organic compounds (VOC), lightning and anthropogenic emissions to the tropospheric ozone budget over Africa and globally using a coupled global chemistry climate model. Our model studies indicate that the photochemical surface ozone concentration may rise by up to 50 ppbv in the burning region during the biomass burning seasons. Biogenic VOCs contribute between 5?20 ppbv to the near surface ozone concentration over the tropical African region. The impact of lightning on surface ozone is negligible, while anthropogenic emissions contribute a maximum of 10 ppbv to the surface ozone over Nigeria, South-Africa and Egypt. The annual average of the surface and column ozone over Africa shows that biomass burning is the single most important emission source affecting the African region, while biogenic emissions have the highest contribution during the rainy seasons. The contributions of African emissions to global tropospheric ozone burden (TOB) are about 9 Tg, 13 Tg, 8 Tg and 4 Tg for African biomass burning, biogenic VOC, lightning and anthropogenic emissions respectively. These correspond to 2.4%, 3.4%, 2.1% and 1% of the global tropospheric ozone budget respectively. Over Africa itself, the contribution of each of these emission types is only 2.4 Tg, 2.2 Tg, 1.4 Tg and 0.8 Tg respectively. Outside the continent, African biogenic VOC emissions yield the highest contribution to the TOB. Our model calculations suggest that about 70% of the tropospheric ozone produced from emissions in Africa is found outside the continent, thus exerting a noticeable influence on a large part of the tropical troposphere. Latin America experiences the highest impact of African emissions, followed by southeast and south-central Asia, Oceania, and the Middle East for all the emission categories; while Canada, the United States, Russia, Mongolia, China and Europe experience the least impact of African emissions
Computational Modeling of Electromagnetically Induced Heating of Magnetic Nanoparticle Materials for Hyperthermic Cancer Treatment
Abstract-We present work on the computational modeling of electromagnetically induced heating in the hyperthermic treatment of cancer using fluid-dispersed magnetic nanoparticles. Magnetic nanoparticle hyperthermia can be used as a complement to chemotherapy or for direct targeting and destruction of tumors through heat treatment. The ability of nanoscale materials to provide an extremely localized therapeutic effect is a major advantage over traditional methods of treatment. When an AC magnetic field is applied to a ferrofluid, Brownian rotation and NĆ©el relaxation of induced magnetic moments result in power dissipation. In order to achieve appreciable volumetric heating, while maintaining safe values of frequency and magnetic field strength, and to reduce the risk of spot heating of healthy tissue, it is necessary to determine an ideal range of input parameters for the driving magnetic field as well as the complex susceptibility of the ferrofluid. We do this by the coupling of the solution of Maxwell's equations in a model of the tumor and surrounding tissue as input to the solution to the Pennes' Bioheat Equation (PBE). In this study, we solve both sets of equations via the Finite Difference Time Domain (FDTD) method as implemented in the program SEMCAD X (by SPEAG, Schmid & Partner Engineering). We use a multilayer model of the human head made up of perfused dermal and skeletal layers and a grey-matter region surrounding a composite region of tumor tissue and the magnetic nanoparticle fluid. The tumor/ferrofluid composite material properties are represented as mean values of the material properties of both constituents, assuming homogeneity of the region. The AC magnetic excitation of the system (within 100 kHz-2 MHz frequency range) is provided by square Helmholtz coils, which provide a uniform magnetic field in the region of interest. The power density derived from the electromagnetic field calculation serves as an input term to the bioheat equation and therefore determines the heating due to the ferrofluid. Results for several variations of input parameters will be presented
Programming Model to Develop Supercomputer Combinatorial Solvers
Ā© 2017 IEEE. Novel architectures for massively parallel machines offer better scalability and the prospect of achieving linear speedup for sizable problems in many domains. The development of suitable programming models and accompanying software tools for these architectures remains one of the biggest challenges towards exploiting their full potential. We present a multi-layer software abstraction model to develop combinatorial solvers on massively-parallel machines with regular topologies. The model enables different challenges in the design and optimization of combinatorial solvers to be tackled independently (separation of concerns) while permitting problem-specific tuning and cross-layer optimization. In specific, the model decouples the issues of inter-node communication, n ode-level scheduling, problem mapping, mesh-level load balancing and expressing problem logic. We present an implementation of the model and use it to profile a Boolean satisfiability solver on simulated massively-parallel machines with different scales and topologies
The Critical Science Plan for DKIST
The 4-meter Daniel K. Inouye Solar Telescope is nearing completion on Haleakala, Maui, with ļ¬rst light expected in 2020. In preparation for early science, the National Solar Observatory is reaching out to the solar community in order to deļ¬ne the critical science goals for the ļ¬rst two years of DKIST operations. The overall aim of this āCritical Science Planā is to be ready, by start of operations, to execute a set of observations that take full advantage of the DKIST capabilities to address critical compelling science
Nonānative species have multiple abundanceāimpact curves
The abundanceāimpact curve is helpful for understanding and managing the impacts of nonānative species. Abundanceāimpact curves can have a wide range of shapes (e.g., linear, threshold, sigmoid), each with its own implications for scientific understanding and management. Sometimes, the abundanceāimpact curve has been viewed as a property of the species, with a single curve for a species. I argue that the abundanceāimpact curve is determined jointly by a nonānative species and the ecosystem it invades, so that a species may have multiple abundanceāimpact curves. Models of the impacts of the invasive mussel Dreissena show how a single species can have multiple, noninterchangeable abundanceāimpact curves. To the extent that ecosystem characteristics determine the abundanceāimpact curve, abundanceāimpact curves based on horizontal designs (spaceāforātime substitution) may be misleading and should be used with great caution, it at all. It is important for scientists and managers to correctly specify the abundanceāimpact curve when considering the impacts of nonānative species. Diverting attention from the invading species to the invaded ecosystem, and especially to the interaction between species and ecosystem, could improve our understanding of how nonānative species affect ecosystems and reduce uncertainty around the effects of management of populations of nonānative species.The abundanceāimpact curve is a useful tool for understanding and managing the impacts of invasive species. Using models based on the impacts of the zebra mussel, I show that a single invasive species can have radically different abundanceāimpact curves in different habitats. This means that managers must be careful to use the correct abundanceāimpact curve and that scientists should avoid using spaceāforātime substitution to understand the impacts of invaders.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/156222/2/ece36364.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156222/1/ece36364_am.pd
A modified version of the Bayley Scales of Infant Development-II for cognitive matching of infants with and without Down syndrome
Background Many measures of infants' early cognitive development, including the BSID-II (The Bayley Scales of Infant Development), mix together test items that assess a number of different developmental domains including language, attention, motor functioning and social abilities, and some items contribute to the assessment of more than one domain. Consequently, the scales may lead to under- or over-estimates of cognitive abilities in some clinical samples and may not be the best measure to use for matching purposes.
Method To address this issue we created a modified form of the BSID-II (the BSID-M) to provide a āpurerā assessment of the general cognitive capacities in infants with Down syndrome (DS) from 6 to 18 months of age. We excluded a number of items that implicated language, motor, attentional and social functioning from the original measure. This modified form was administered to 17 infants with Down syndrome when 6, 12 and 18 months old and to 41 typically developing infants at 4, 7 and 10 months old.
Results The results suggested that the modified form continued to provide a meaningful and stable measure of cognitive functioning and revealed that DS infants may score marginally higher in terms of general cognitive abilities when using this modified form than they might when using the standard BSID-II scales.
Conclusions This modified form may be useful for researchers who need a āpurerā measure with which to match infants with DS and other infants with intellectual disabilities on cognitive functioning
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Low level waste shipment accident lessons learned
On October 1, 1994 a shipment of low-level waste from the Fernald Environmental Management Project, Fernald, Ohio, was involved in an accident near Rolla, Missouri. The accident did not result in the release of any radioactive material. The accident did generate important lessons learned primarily in the areas of driver and emergency response communications. The shipment was comprised of an International Standards Organization (ISO) container on a standard flatbed trailer. The accident caused the low-level waste package to separate from the trailer and come to rest on its top in the median. The impact of the container with the pavement and median inflicted relatively minor damage to the container. The damage was not substantial enough to cause failure of container integrity. The success of the package is attributable to the container design and the packaging procedures used at the Fernald Environmental Management Project for low-level waste shipments. Although the container survived the initial wreck, is was nearly breached when the first responders attempted to open the ISO container. Even though the container was clearly marked and the shipment documentation was technically correct, this information did not identify that the ISO container was the primary containment for the waste. The lessons learned from this accident have DOE complex wide applicability. This paper is intended to describe the accident, subsequent emergency response operations, and the lessons learned from this incident
Supporting Earth-Observation Calibration and Validation: A new generation of tools for crowdsourcing and citizen science
Citizens are providing vast amounts of georeferenced data in the form of in situ data collections as well as interpretations and digitization of Earth-observation (EO) data sets.
These new data streams have considerable potential for supporting the calibration and validation of current and future products derived from EO. We provide a general introduction to this growing area of interest and review existing crowdsourcing and citizen science (CS) initiatives of relevance to EO. We then draw upon our own experiences to provide case studies that highlight different types of data collection and citizen engagement and discuss the various barriers to adoption.
Finally, we highlight opportunities for how citizens can become part of an integrated EO monitoring system in the framework of the European Union (EU) space program, including Copernicus and other monitoring initiatives
Dioxygenolytic cleavage of aryl ether bonds: 1,10-dihydro-1,10-dihydroxyfluoren-9-one, a novel arene dihydrodiol as evidence for angular dioxygenation of dibenzofuran
Two dibenzofuran degrading bacteria, Brevibacterium strain DPO 1361 and strain DPO 220, were found to utilize fluorene as sole source of carbon and energy. Cells which were grown on dibenzofuran, transformed fluorene into a number of products. For five of the seven metabolites isolated, the structure could be established unequivocally. Accumulation of one metabolite, 1,10-dihydroxy-1, 10-dihydrofluoren-9-one, indicated the presence of a novel type of dioxygenase, attacking polynuclear aromatic systems in the unusual angular position. Dibenzofuran degradation is proposed to likewise proceed via initial angular dioxygenation. Only aryl oxygen ether bond, which normally is extremely stable, is thus transformed to a hemiacetal. After spontaneous cleavage and subsequent rearomatization by dehydration, 2,2′,3-trihydroxybiphenyl [3-(2-hydroxyphenyl)-catechol] thus results as the immediate product of the first enzymatic reaction in the degradation sequence
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