Soft-bottom benthic assemblages and levels of contaminants in sediments and biota at Gray's Reef National Marine Sanctuary and nearby shelf waters off the coast of Georgia (2000 and 2001)

A series of studies was initiated to assess the condition of benthic macroinfauna and chemical contaminant levels in sediments and biota of the Gray’s Reef National Marine Sanctuary (GRNMS) and nearby shelf waters off the coast of Georgia. Four key objectives of the research are (1) to document existing environmental conditions within the sanctuary in order to provide a quantitative benchmark for tracking any future changes due to either natural or human disturbances; (2) to examine broader cross-shelf spatial patterns in benthic fauna and sediment contaminant concentrations and to identify potential controlling factors associated with the observed patterns; (3) to assess any between-year temporal variability in benthic fauna; and (4) to evaluate the importance of benthic fauna as prey for higher trophic levels. Such questions are being addressed to help fulfill long-term science and management goals of the GRNMS. However, it is anticipated that the information will be of additional value in broadening our understanding of the surrounding South Atlantic Bight (SAB) ecosystem and in bringing the knowledge to bear on related resourcemanagement issues of the region. We have begun to address the first three of these objectives with data from samples collected in spring 2000 at stations within GRNMS, and in spring 2001 at stations within the sanctuary and along three cross-shelf transects extending from the mouths of Sapelo, Doboy, and Altamaha Sounds out to sanctuary depths (about 17-20 m). This report provides a description of baseline conditions within the sanctuary, based on results of the spring 2000 survey (Section II), and uses data from both 2000 and 2001 to examine overall spatial and temporal patterns in biological and chemical variables within the sanctuary and surrounding inner-shelf environment (Section III). (PDF contains 65 pages)

Distribution and sighting frequency of reef fishes in the Florida Keys National Marine Sanctuary

This study analyzed species richness, distribution, and sighting frequency of selected reef fishes to describe species assemblage composition, abundance, and spatial distribution patterns among sites and regions (Upper Keys, Middle Keys, Lower Keys, and Dry Tortugas) within the Florida Keys National Marine Sanctuary (FKNMS) barrier reef ecosystem. Data were obtained from the Reef Environmental Education Foundation (REEF) Fish Survey Project, a volunteer fish-monitoring program. A total of 4,324 visual fish surveys conducted at 112 sites throughout the FKNMS were used in these analyses. The data set contained sighting information on 341 fish species comprising 68 families. Species richness was generally highest in the Upper Keys sites (maximum was 220 species at Molasses Reef) and lowest in the Dry Tortugas sites. Encounter rates differed among regions, with the Dry Tortugas having the highest rate, potentially a result of differences in the evenness in fishes and the lower diversity of habitat types in the Dry Tortugas region. Geographic coverage maps were developed for 29 frequently observed species. Fourteen of these species showed significant regional variation in mean sighting frequency (%SF). Six species had significantly lower mean %SF and eight species had significantly higher mean %SF in the Dry Tortugas compared with other regions. Hierarchical clustering based on species composition (presence-absence) and species % SF revealed interesting patterns of similarities among sites that varied across spatial scales. Results presented here indicate that phenomena affecting reef fish composition in the FKNMS operate at multiple spatial scales, including a biogeographic scale that defines the character of the region as a whole, a reef scale (~50-100 km) that include meso-scale physical oceanographic processes and regional variation in reef structure and associated reef habitats, and a local scale that includes level of protection, cross-shelf location and a suite of physical characteristics of a given reef. It is likely that at both regional and local scales, species habitat requirements strongly influence the patterns revealed in this study, and are particularly limiting for species that are less frequently observed in the Dry Tortugas. The results of this report serve as a benchmark for the current status of the reef fishes in the FKNMS. In addition, these data provide the basis for analyses on reserve effects and the biogeographic coupling of benthic habitats and fish assemblages that are currently underway. (PDF contains 61 pages.)

Large-eddy simulation of turbulent collision of heavy particles in isotropic turbulence

The small-scale motions relevant to the collision of heavy particles represent a general challenge to the conventional large-eddy simulation (LES) of turbulent particle-laden flows. As a first step toward addressing this challenge, we examine the capability of the LES method with an eddy viscosity subgrid scale (SGS) model to predict the collision-related statistics such as the particle radial distribution function at contact, the radial relative velocity at contact, and the collision rate for a wide range of particle Stokes numbers. Data from direct numerical simulation (DNS) are used as a benchmark to evaluate the LES using both a priori and a posteriori tests. It is shown that, without the SGS motions, LES cannot accurately predict the particle-pair statistics for heavy particles with small and intermediate Stokes numbers, and a large relative error in collision rate up to 60% may arise when the particle Stokes number is near St_K=0.5. The errors from the filtering operation and the SGS model are evaluated separately using the filtered-DNS (FDNS) and LES flow fields. The errors increase with the filter width and have nonmonotonic variations with the particle Stokes numbers. It is concluded that the error due to filtering dominates the overall error in LES for most particle Stokes numbers. It is found that the overall collision rate can be reasonably predicted by both FDNS and LES for St_K>3. Our analysis suggests that, for St_K<3, a particle SGS model must include the effects of SGS motions on the turbulent collision of heavy particles. The spectral analysis of the concentration fields of the particles with different Stokes numbers further demonstrates the important effects of the small-scale motions on the preferential concentration of the particles with small Stokes numbers.

Extending Distance-based Ranking Models In Estimation of Distribution Algorithms

Recently, probability models on rankings have been proposed in the field of estimation of distribution algorithms in order to solve permutation-based combinatorial optimisation problems. Particularly, distance-based ranking models, such as Mallows and Generalized Mallows under the Kendall’s-t distance, have demonstrated their validity when solving this type of problems. Nevertheless, there are still many trends that deserve further study. In this paper, we extend the use of distance-based ranking models in the framework of EDAs by introducing new distance metrics such as Cayley and Ulam. In order to analyse the performance of the Mallows and Generalized Mallows EDAs under the Kendall, Cayley and Ulam distances, we run them on a benchmark of 120 instances from four well known permutation problems. The conducted experiments showed that there is not just one metric that performs the best in all the problems. However, the statistical test pointed out that Mallows-Ulam EDA is the most stable algorithm among the studied proposals.

High Order Multi-Moment Constrained Finite Volume Method. Part I: Basic Formulation

A new high-order finite volume method based on local reconstruction is presented in this paper. The method, so-called the multi-moment constrained finite volume (MCV) method, uses the point values defined within single cell at equally spaced points as the model variables (or unknowns). The time evolution equations used to update the unknowns are derived from a set of constraint conditions imposed on multi kinds of moments, i.e. the cell-averaged value and the point-wise value of the state variable and its derivatives. The finite volume constraint on the cell-average guarantees the numerical conservativeness of the method. Most constraint conditions are imposed on the cell boundaries, where the numerical flux and its derivatives are solved as general Riemann problems. A multi-moment constrained Lagrange interpolation reconstruction for the demanded order of accuracy is constructed over single cell and converts the evolution equations of the moments to those of the unknowns. The presented method provides a general framework to construct efficient schemes of high orders. The basic formulations for hyperbolic conservation laws in 1- and 2D structured grids are detailed with the numerical results of widely used benchmark tests. (C) 2009 Elsevier Inc. All rights reserved.

Unilateral vs. Bilateral link-formation: Bridging the gap

We provide a model that bridges the gap between two benchmark models of strategic network formation: Jackson and Wolinsky' s model based on bilateral formation of links, and Bala and Goyal's two-way fl ow model, where links can be unilaterally formed. In the model introduced and studied here a link can be created unilaterally. When it is only supported by one of the two players the fl ow through the link suffers a certain decay, but when it is supported by both the fl ow runs without friction. When the decay in links supported by only one player is maximal (i.e. there is no flow) we have Jackson and Wolinsky 's connections model without decay, while when flow in such links is perfect we have Bala and Goyal' s two-way flow model. We study Nash, strict Nash and pairwise stability for the intermediate models. Efficiency and dynamics are also examined.

Laser action from 1,3,5,7-tetramethyl-2,6-diethyl-8-n-propyl pyrromethene-BF2

We measured spectroscopic and laser action properties of a novel 8-position substituted pyrromethene-BF2, namely 1,3,5,7-tetramethyl-2,6-diethyl-8-n-propyl pyrromethene-BF2 complex. The laser action was performed with the corresponding dye solution in ethanol, which was placed in a Littman-type laser cavity pumped by the second harmonic of a Q-switched Nd:YAG laser. The spectroscopic measurements clearly indicated that the corresponding dye solution in ethanol exhibited intense absorption in the visible spectral region with large fluorescence quantum yield. It possesses rather low triplet-triplet absorption in the spectral region 460-550 nm and almost negligible triplet-triplet absorption in the lasing spectral region. As a consequence, it lases nearly as efficiently as commercially available benchmark laser dyes such as Rhodamine-6G and outperformed them in wavelength tunability in our laser cavity and pump geometry. (C) 2002 Optical Society of America.

From bilateral two-way to unilateral one-way flow link-formation

Documento de trabajo

Probabilistic robust control : theory and applications

In this work, the development of a probabilistic approach to robust control is motivated by structural control applications in civil engineering. Often in civil structural applications, a system's performance is specified in terms of its reliability. In addition, the model and input uncertainty for the system may be described most appropriately using probabilistic or "soft" bounds on the model and input sets. The probabilistic robust control methodology contrasts with existing H∞/μ robust control methodologies that do not use probability information for the model and input uncertainty sets, yielding only the guaranteed (i.e., "worst-case") system performance, and no information about the system's probable performance which would be of interest to civil engineers.

The design objective for the probabilistic robust controller is to maximize the reliability of the uncertain structure/controller system for a probabilistically-described uncertain excitation. The robust performance is computed for a set of possible models by weighting the conditional performance probability for a particular model by the probability of that model, then integrating over the set of possible models. This integration is accomplished efficiently using an asymptotic approximation. The probable performance can be optimized numerically over the class of allowable controllers to find the optimal controller. Also, if structural response data becomes available from a controlled structure, its probable performance can easily be updated using Bayes's Theorem to update the probability distribution over the set of possible models. An updated optimal controller can then be produced, if desired, by following the original procedure. Thus, the probabilistic framework integrates system identification and robust control in a natural manner.

The probabilistic robust control methodology is applied to two systems in this thesis. The first is a high-fidelity computer model of a benchmark structural control laboratory experiment. For this application, uncertainty in the input model only is considered. The probabilistic control design minimizes the failure probability of the benchmark system while remaining robust with respect to the input model uncertainty. The performance of an optimal low-order controller compares favorably with higher-order controllers for the same benchmark system which are based on other approaches. The second application is to the Caltech Flexible Structure, which is a light-weight aluminum truss structure actuated by three voice coil actuators. A controller is designed to minimize the failure probability for a nominal model of this system. Furthermore, the method for updating the model-based performance calculation given new response data from the system is illustrated.

Mecanizado por torneado en duro

[ES]Los objetivos del siguiente trabajo consisten en analizar e optimizar el proceso del torneado en duro del acero ASP-23 indagando de especial manera en la realización de diferentes soluciones para brochas. En este caso, este proyecto nace de la importancia de reducir así como los costes económicos y los costes temporales de fabricación de elementos basados en el acero ASP-23 mediante el torneado en duro; proceso de mecanizado, cuya importancia cada vez es mayor como en las industrias de automoción o aeronáutica. El desarrollo del proyecto es fruto de la necesidad de EKIN S. Coop, uno de los líderes en los procesos de máquina-herramienta de alta precisión para el brochado, de desarrollar un proceso de mecanizado más eficaz de las brochas que produce. Así en el aula máquina-herramienta (ETSIB) se han intentado demostrar los beneficios que tiene el torneado en duro en el mecanizado del ASP-23. Hoy en día, con el rápido desarrollo de nuevos materiales, los procesos de fabricación se están haciendo cada vez más complejos, por la amplia variedad de maquinas con las que se realizan los procesos, por la variedad de geometría/material de las herramientas empleadas, por las propiedades del material de la pieza a mecanizar, por los parámetros de corte tan variados con los que podemos implementar el proceso (profundidad de corte, velocidad, alimentación...) y por la diversidad de elementos de sujeción utilizados. Además debemos ser conscientes de que tal variedad implica grandes magnitudes de deformaciones, velocidades y temperaturas. He aquí la justificación y el gran interés en el proyecto a realizar. Por ello, en este proyecto intentamos dar un pequeño paso en el conocimiento del proceso del torneado en duro de aceros con poca maquinabilidad, siendo conscientes de la amplia variedad y dificultad del avance en la ingeniería de fabricación y del mucho trabajo que queda por hacer.

Serviço social e saúde da família: perspectivas de inserção e prática profissional

O presente trabalho tem como objetivo reconhecer as experiências de inserção do assistente social na Saúde da Família e as tendências da prática profissional nessa área. Diante das repercussões da contrarreforma na política e nas práticas de saúde, questionamos como o Serviço Social tem pautado suas experiências de inserção frente às contradições da Saúde da Família. Para isso, a pesquisa é baseada no referencial crítico dialético, em que utilizamos a metodologia da pesquisa documental com levantamento quanti-qualitativo. A análise foi realizada a partir das comunicações com referência à Saúde da Família do Congresso Brasileiro de Assistentes Sociais (CBAS) e Congresso Nacional de Serviço Social em Saúde (CONASSS) entre os anos de 2000 a 2009. Nos trabalhos foram identificados três eixos temáticos: Análise da Estratégia, Relato de experiência e Reflexão das possibilidades de inserção. A partir desses eixos buscamos reconhecer a dimensão teórico-metodológica, ético-política e técnico-operativa. Os resultados apontam que os assistentes sociais têm ocupado predominantemente funções de suporte em equipes de referência e que esta tem se apresentado como a possibilidade de inserção oficial através do NASF. Nas abordagens reconhecemos que as experiências pautadas na perspectiva crítica contam com histórico de articulação com os movimentos sociais, com referência à Reforma Sanitária e as discussões da categoria, e na prática, esses conceitos direcionam o processo de trabalho. Verificamos que há uma tendência majoritária de incorporação do discurso do Ministério da Saúde quanto à estrutura e processo de trabalho em Saúde da Família, o que tem contribuído para a incorporação de instrumentais construídos pela Estratégia na prática profissional. Essa tendência aponta que a inserção dos assistentes sociais na Saúde da Família tem recebido influências de vertentes neoconservadoras e sofrido os impactos da contrarreforma na política de saúde.

Models in the implementation of the Water Framework Directive - benchmarking as part of the modelling proccess

The Water Framework Directive (WFD; European Commission 2000) is a framework for European environmental legislation that aims at improving water quality by using an integrated approach to implement the necessary societal and technical measures. Assessments to guide, support, monitor and evaluate policies, such as the WFD, require scientific approaches which integrate biophysical and human aspects of ecological systems and their interactions, as outlined by the International Council for Science (2002). These assessments need to be based on sound scientific principles and address the environmental problems in a holistic way. End-users need help to select the most appropriate methods and models. Advice on the selection and use of a wide range of water quality models has been developed within the project Benchmark Models for the Water Framework Directive (BMW). In this article, the authors summarise the role of benchmarking in the modelling process and explain how such an archive of validated models can be used to support the implementation of the WFD.

A variational framework for spectral discretization of the density matrix in Kohn Sham density functional theory

Kohn-Sham density functional theory (KSDFT) is currently the main work-horse of quantum mechanical calculations in physics, chemistry, and materials science. From a mechanical engineering perspective, we are interested in studying the role of defects in the mechanical properties in materials. In real materials, defects are typically found at very small concentrations e.g., vacancies occur at parts per million, dislocation density in metals ranges from $10^{10} m^{-2}$ to $10^{15} m^{-2}$, and grain sizes vary from nanometers to micrometers in polycrystalline materials, etc. In order to model materials at realistic defect concentrations using DFT, we would need to work with system sizes beyond millions of atoms. Due to the cubic-scaling computational cost with respect to the number of atoms in conventional DFT implementations, such system sizes are unreachable. Since the early 1990s, there has been a huge interest in developing DFT implementations that have linear-scaling computational cost. A promising approach to achieving linear-scaling cost is to approximate the density matrix in KSDFT. The focus of this thesis is to provide a firm mathematical framework to study the convergence of these approximations. We reformulate the Kohn-Sham density functional theory as a nested variational problem in the density matrix, the electrostatic potential, and a field dual to the electron density. The corresponding functional is linear in the density matrix and thus amenable to spectral representation. Based on this reformulation, we introduce a new approximation scheme, called spectral binning, which does not require smoothing of the occupancy function and thus applies at arbitrarily low temperatures. We proof convergence of the approximate solutions with respect to spectral binning and with respect to an additional spatial discretization of the domain. For a standard one-dimensional benchmark problem, we present numerical experiments for which spectral binning exhibits excellent convergence characteristics and outperforms other linear-scaling methods.

Mondragon Taldea: Hazkunde-bide ezberdinak

Hurrengo lanean, Mondragon Korporazio Kooperatiboaren parte diren BATZ, S.Coop. eta DANOBAT S.Coop. enpresak aztertuko dira, batez ere hazkunde prozesuan zentratuz. Azterketa hau burutu ahal izateko, lehendabizi sarrera labur bat egingo da gaian kokatzeko eta lan honen bidez lortu nahi diren helburuak finkatuko dira bertan. Era berean, enpresen azterketa hasi baino lehen hauek kokatuta dauden ingurunearen azterketa burutuko da, jardueran eragina izango duten faktore ekonomikoak, politikoak eta abar identifikatzeko. Lanean zehar analizatuko diren bi enpresek azterketa puntu berdinak izango dituzte. Lehendabizi enpresaren ezaugarriak eta historia laburra aztertuko dira. Aurkezpen orokor honen ondoren, ingurune bereziaren azterketa gauzatuko da, enpresak sektore konkretu batean kokatuz eta sektore honen ezaugarriak identifikatuz. Kanpo analisiarekin bukatuz, enpresaren barne analisian aurkitzen diren arlo funtzionala eta baliabide eta gaitasunen azterketa burutuko da eta AMIA analisia gauzatuko da enpresaren ezaugarri espezifikoak ezagutzeko. Enpresaren ezaugarrien analisiarekin bukatu ondoren, hazkunde estrategia izango da aztergai, bertan korporazio estrategia, kanpo hazkundea, barne hazkundea eta lankidetza akordioak ikertuko dira. Azkenik, enpresa bakoitzaren azterketa burutu ondoren ondorio nagusiak aurkituko dira, bertan hasiera batean finkatutako helburuak bete diren ikusi ahal izango da, eta analisiaren ondorioz enpresen hazkundeari buruzko ideia nagusiak aurkituko dira. Erabilitako informazio guztiaren iturriak bibliografia apartatuan ikusi ahal izango dira.