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Sample records for feminino precisa sair

  1. Locomotion and body proportions of the Saint-Césaire 1 Châtelperronian Neandertal

    PubMed Central

    Trinkaus, Erik; Ruff, Christopher B.; Churchill, Steven E.; Vandermeersch, Bernard

    1998-01-01

    The initial Upper Paleolithic (Châtelperronian) of western Europe was associated with late European Neandertals, best known through the Saint-Césaire 1 partial skeleton. Biomechanical cross-sectional analysis of the Saint-Césaire 1 femoral diaphysis at the subtrochanteric and midshaft levels, given the plasticity of mammalian diaphyseal cortical bone, provides insights into the habitual levels and patterns of loading on the lower limbs from body mass, proportions, and locomotion. The overall robustnesses of the femoral diaphyses of European Neandertals and early modern humans are similar once contrasts in body proportions are incorporated into the body size scaling. Saint-Césaire 1 matches these samples only if it is provided with Neandertal-like hyperarctic body proportions. And the rounded proximal femoral diaphysis of Saint-Césaire 1 is similar to those of earlier Neandertals, likely also reflecting similar cold-adapted broad pelvic regions. However, although morphologically similar to those of archaic Homo, the Saint-Césaire 1 femoral midshaft exhibits the anteroposterior reinforcement characteristic of early modern humans. Consequently, Saint-Césaire 1 appears as a morphological Neandertal with hyperarctic body proportions who nonetheless had shifted locomotor patterns to more closely resemble those of other Upper Paleolithic humans. PMID:9576971

  2. A Robust Reweighted L₁-Minimization Imaging Algorithm for Passive Millimeter Wave SAIR in Near Field.

    PubMed

    Zhang, Yilong; Li, Yuehua; Zhu, Shujin; Li, Yuanjiang

    2015-01-01

    The Compressive Sensing (CS) approach has proven to be useful for Synthetic Aperture Interferometric Radiometer (SAIR) imaging because it provides the same high-resolution capability while using part of interferometric observations compared to traditional methods using the entirety. However, it cannot always obtain the sparsest solution and may yield outliers with the non-adaptive random measurement matrix adopted by current CS models. To solve those problems, this paper proposes a robust reweighted L₁-minimization imaging algorithm, called RRIA, to reconstruct images accurately by combining the sparsity and prior information of SAIR images in near field. RRIA employs iterative reweighted L₁-minimization to enhance the sparsity to reconstruct SAIR images by computing a new weight factor in each iteration according to the previous SAIR images. Prior information estimated by the energy functional of SAIR images is introduced to RRIA as an additional constraint condition to make the algorithm more robust for different complex scenes. Compared to the current basic CS approach, our simulation results indicate that RRIA can achieve better recovery with the same amount of interferometric observations. Experimental results of different scenes demonstrate the validity and robustness of RRIA. PMID:26404282

  3. A Robust Reweighted L1-Minimization Imaging Algorithm for Passive Millimeter Wave SAIR in Near Field

    PubMed Central

    Zhang, Yilong; Li, Yuehua; Zhu, Shujin; Li, Yuanjiang

    2015-01-01

    The Compressive Sensing (CS) approach has proven to be useful for Synthetic Aperture Interferometric Radiometer (SAIR) imaging because it provides the same high-resolution capability while using part of interferometric observations compared to traditional methods using the entirety. However, it cannot always obtain the sparsest solution and may yield outliers with the non-adaptive random measurement matrix adopted by current CS models. To solve those problems, this paper proposes a robust reweighted L1-minimization imaging algorithm, called RRIA, to reconstruct images accurately by combining the sparsity and prior information of SAIR images in near field. RRIA employs iterative reweighted L1-minimization to enhance the sparsity to reconstruct SAIR images by computing a new weight factor in each iteration according to the previous SAIR images. Prior information estimated by the energy functional of SAIR images is introduced to RRIA as an additional constraint condition to make the algorithm more robust for different complex scenes. Compared to the current basic CS approach, our simulation results indicate that RRIA can achieve better recovery with the same amount of interferometric observations. Experimental results of different scenes demonstrate the validity and robustness of RRIA. PMID:26404282

  4. Diet and behavior of the Saint-Césaire Neanderthal inferred from biogeochemical data inversion.

    PubMed

    Balter, Vincent; Simon, Laurent

    2006-10-01

    Biogeochemistry is a powerful tool for dietary reconstruction, and mixing equations can be used to quantify the contribution of multiple sources to an individual's diet. The goals of this paper are: 1) to generalize the inverse method to dietary mixtures; and 2) to reconstruct the diet of the Saint-Césaire Neanderthal using Sr/Ca and Ba/Ca data of the mineral fraction of bone (hydroxylapatite), and with published delta13C and delta15N data of the associated organic fraction of bone (collagen). A new method is proposed to calculate the maximum diagenetic contribution of the Sr/Ba ratio, assuming that the soil soluble fraction is the diagenetic end-member and, for a given fraction of diagenesis, allows the restoration of the original Sr/Ba ratio. Considering the Saint-Césaire Châtelperronian mammalian assemblage as the meat source, and on the basis of available Sr, Ba, and Ca contents of plants, the results indicate that the percentage of plants in the Neanderthal's diet must have been close to zero for realistic Sr and Ba impoverishment between diet and hydroxylapatite. Contrary to previous studies, it is shown that fish could constitute a significant proportion (30%) of the diet of the Saint-Césaire Neanderthal. However, this mass balance solution is not supported by the zooarchaeological data. When the entire faunal assemblage is considered as the dietary source, the calculation shows that bovids (except reindeer) represent the greatest percentage of consumed meat (58%), followed by horses/rhinoceros (22%), reindeer (13%), and mammoths (7%). These respective percentages are in close accordance with zooarchaeological records, suggesting that the faunal assemblage associated with the Neanderthal of Saint-Césaire reliably reflects what he ate during the last few years of his life. In behavioral terms, this result supports the hypothesis that this Neanderthal carried the foodstuffs back to the Saint-Césaire shelter before their consumption. PMID:16908051

  5. La diaphyse fémorale droite du squelette néandertalien de Saint-Césaire (Charente, France)The right femoral shaft of the Neanderthal skeleton of Saint-Césaire (Charente, France)

    NASA Astrophysics Data System (ADS)

    Del Prete, Aurélie; Vandermeersch, Bernard

    2001-07-01

    The Neanderthal skeleton from Saint-Césaire (France) shows a fragmentary right femora. We have decided to study the morphology and the metric proportions of this fragment. We have made a comparison with the other Neanderthal femora and with a sample of recent humans ( N=181) from European collections. It seems that this fragment of femora is clearly identical to other Neanderthal femora.

  6. spxA2, encoding a regulator of stress resistance in Bacillus anthracis, is controlled by SaiR, a new member of the Rrf2 protein family

    PubMed Central

    Nakano, Michiko M.; Kominos-Marvell, Wren; Sane, Bhagyashree; Nader, Yaldah Mohammad; Barendt, Skye M.; Jones, Marcus B.; Zuber, Peter

    2014-01-01

    Summary Spx, a member of the ArsC (arsenate reductase) protein family, is conserved in Gram-positive bacteria, and interacts with RNA polymerase to activate transcription in response to toxic oxidants. In Bacillus anthracis str. Sterne, resistance to oxidative stress requires the activity of two paralogues, SpxA1 and SpxA2. Suppressor mutations were identified in spxA1 mutant cells that conferred resistance to hydrogen peroxide. The mutations generated null alleles of the saiR gene and resulted in elevated spxA2 transcription. The saiR gene resides in the spxA2 operon and encodes a member of the Rrf2 family of transcriptional repressors. Derepression of spxA2 in a saiR mutant required SpxA2, indicating an autoregulatory mechanism of spxA2 control. Reconstruction of SaiR-dependent control of spxA2 was accomplished in Bacillus subtilis, where deletion analysis uncovered two cis-elements within the spxA2 regulatory region that are required for repression. Mutations to one of the sequences of dyad symmetry substantially reduced SaiR binding and SaiR-dependent repression of transcription from the spxA2 promoter in vitro. Previous studies have shown that spxA2 is one of the most highly induced genes in a macrophage infected with B. anthracis. The work reported herein uncovered a key regulator, SaiR, of the Spx system of stress response control. PMID:25231235

  7. Radiocarbon dates from the Grotte du Renne and Saint-Césaire support a Neandertal origin for the Châtelperronian

    PubMed Central

    Hublin, Jean-Jacques; Talamo, Sahra; Julien, Michèle; David, Francine; Connet, Nelly; Bodu, Pierre; Vandermeersch, Bernard; Richards, Michael P.

    2012-01-01

    The transition from the Middle Paleolithic (MP) to Upper Paleolithic (UP) is marked by the replacement of late Neandertals by modern humans in Europe between 50,000 and 40,000 y ago. Châtelperronian (CP) artifact assemblages found in central France and northern Spain date to this time period. So far, it is the only such assemblage type that has yielded Neandertal remains directly associated with UP style artifacts. CP assemblages also include body ornaments, otherwise virtually unknown in the Neandertal world. However, it has been argued that instead of the CP being manufactured by Neandertals, site formation processes and layer admixture resulted in the chance association of Neanderthal remains, CP assemblages, and body ornaments. Here, we report a series of accelerator mass spectrometry radiocarbon dates on ultrafiltered bone collagen extracted from 40 well-preserved bone fragments from the late Mousterian, CP, and Protoaurignacian layers at the Grotte du Renne site (at Arcy-sur-Cure, France). Our radiocarbon results are inconsistent with the admixture hypothesis. Further, we report a direct date on the Neandertal CP skeleton from Saint-Césaire (France). This date corroborates the assignment of CP assemblages to the latest Neandertals of western Europe. Importantly, our results establish that the production of body ornaments in the CP postdates the arrival of modern humans in neighboring regions of Europe. This new behavior could therefore have been the result of cultural diffusion from modern to Neandertal groups. PMID:23112183

  8. Complexity of the Earth's space-atmosphere interaction region (SAIR) response to the solar flux at 10.7 cm as seen through the evaluation of five solar cycle two-line element (TLE) records

    NASA Astrophysics Data System (ADS)

    Molaverdikhani, Karan; Ajabshirizadeh, Ali; Davoudifar, Pantea; Lashkanpour, Majid

    2016-09-01

    Orbital debris are long-standing threats to space systems. They also contribute to the flux of macroscopic particles into the Earth's atmosphere and eventually affects environmental processes across several other related regions. As impactful space debris may be, debris along with other Low Earth Orbit (LEO) orbiting objects, also serve as valuable long-monitoring probes to deduce the properties of geospace environment in-situ. We define the Daily Decay Rate (DDR) as a suitable indicator of how the Earth's space-atmosphere interaction region (SAIR) responds to solar activity and how solar activity directly affects the orbital evolution of a LEO orbiter. We present a computationally simplified technique that simultaneously solves the motion equations for DDR and cross-sectional area to mass ratio (A/m) from consecutive TLE records. By evaluating more than 50 million TLE records we estimate A/m of 15,307 NORAD-indexed objects and determine how DDR varies. We observe the thermospheric "natural thermostat" in our results, consistent with previous studies. We compare the observed DDRs with two models based on NRLMSISE-00 and DTM-2013, and present evidence the models display a systemic altitudinal bias. We propose several possibilities to explain this altitudinal bias including the overestimated CD at low altitudes in our models (presumably due to the despinning effect of perturbing forces on the orbiting objects), and incomplete and limited coverage of in-situ observations at high solar activity. We conclude that the density models do not reliably reproduce the densities and atmospheric-thermospheric behaviors at high solar active conditions, especially for F10.7 cm above 300 sfu.

  9. Interest in Evening Courses: Survey Analysis. SAIR Conference Paper.

    ERIC Educational Resources Information Center

    Bottomley, Wayne N.; And Others

    Student interest in increased evening courses at Daytona Beach Campus of Embry-Riddle Aeronautical University (ERAU) was investigated. The proportion of students employed while attending ERAU and student attitudes concerning evening or Saturday courses were also determined. Of the 3,312 students preregistered for fall 1982, 862 completed a…

  10. Not Your Average Data Base. SAIR Conference Paper.

    ERIC Educational Resources Information Center

    Bloom, Allan M.; Winstead, Wayland H.

    The development of an unusual database at Virginia Polytechnic Institute and State University (Virginia Tech) is described. The Student Census-date Report File (STUCENFL) was designed to meet both internal and external data recipients' needs for student-related information. Attention is directed to needs for the database, underlying design…

  11. Strategic Planning vs. Disjointed Incrementalism: An Institutional Research Perspective. SAIR Conference Paper.

    ERIC Educational Resources Information Center

    Jean, Paul M.; And Others

    Strategic planning in higher education is discussed from the perspective of institutional research. Attention is directed to: institutional mission, institutional assessment, institutional leadership, environmental assessment, market analysis, and competitive position. Strategic planning merges incrementalism, which focuses on flexibility,…

  12. Producing "Service to Non-Major" Reports Without an ICLM via NCHEMS. SAIR Conference Paper.

    ERIC Educational Resources Information Center

    McCord, Michael T.; Ingle, Robert

    The procedures for producing a report on departmental service to nonmajors are described in detail. The objective was to provide information for decision-making needs without reliance on the standardized pre-packaged models. An alternative to the Induced Course Load Matrix (ICLM) of the Resource Requirements Prediction Model (RRPM) package of the…

  13. Predicting Attrition in Admissions Using a Discriminant Model. SAIR Conference Paper.

    ERIC Educational Resources Information Center

    Yost, Michael

    A mathematical model designed to identify admitted college applicants who pay a tuition deposit but fail to attend the college was tested. A two-group discriminant model was built using 486 Trinity University students who paid deposits and enrolled as freshmen during the 1983-1984 academic year, and 72 persons who paid tuition deposits but did not…

  14. A Longitudinal Evaluation of the Rate of Flow of Freshman Applications and Freshman Tuition Deposits. SAIR Conference Paper.

    ERIC Educational Resources Information Center

    Yost, Michael

    Freshmen recruitment and admissions trends at Trinity University, a small, independent Texas university, are described. Attention is directed to the weekly rates at which freshman applications and tuition deposits were received over a 4-year time period. The patterns of the receipt of applications and deposits were consistent across years. The…

  15. Grambling State University's Planning/Budgeting Model: An Integral Component of a Decision Support System. SAIR Conference Paper.

    ERIC Educational Resources Information Center

    Lundy, Harold W.

    The development of a planning/budgeting model as an integral component of a decision support system is described. The case study approach is used to describe how Grambling State University (GSU) developed the model to improve its financial planning and budgeting processes. The model can be used for tactical and/or strategic planning. The model is…

  16. Les Néandertaliens étaient-ils essentiellement carnivores ? Résultats préliminaires sur les teneurs en Sr et en Ba de la paléobiocénose mammalienne de Saint-CésaireWere Neandertalians essentially carnivores? Sr and Ba preliminary results of the mammalian palaeobiocoenosis of Saint-Césaire

    NASA Astrophysics Data System (ADS)

    Balter, Vincent; Person, Alain; Labourdette, Nathalie; Drucker, Dorothée; Renard, Maurice; Vandermeersch, Bernard

    2001-01-01

    Strontium-calcium (Sr/Ca) and barium-calcium (Ba/Ca) ratios are reduced constantly between diet and bioapatite in mammal organisms. This phenomenon leads to a reduction in the Sr/Ca and Ba/Ca ratios at higher trophic level in predator-prey mammalian communities, and is applied here to the reconstruction of a castelperronian food web, which includes a Neanderthal specimen. Adapted chemical pretreatment allows to isolate bioapatite from diagenetic compounds for analysis of Ca, Sr and Ba. Sr/Ca and Ba/Ca results of the fauna are consistent with trophic predictions. Initial results for the Neandertal suggest that he was mostly carnivorous. Distribution of Ba/Ca values of bones of herbivorous taxa reveals that ruminant animals can be distinguished from non-ruminants. The biosegregation model predicts that the diet of the Neandertal was composed by about 97 % in weight of meat with a weak contribution of vegetable or fish, and that the association of fish and plant is excluded in any proportion.

  17. The Future of Institutional Research. Proceedings of the Annual Conference of the Southern Association for Institutional Research (Orlando, Florida, October 24-26, 1979).

    ERIC Educational Resources Information Center

    Salley, Charles D., Ed.; And Others

    Proceedings of the 1979 conference of the Southern Association for Institutional Research (SAIR) are presented. The conference theme was the future of institutional research. Contents include reports of preconference workshops, speeches, panel reports, abstracts of papers, and reports pertaining to the affairs of the SAIR. Documents and authors…

  18. The Practice of Institutional Research. Proceedings of a Joint Conference of the Southern Association for Institutional Research and the North Carolina Association for Institutional Research (Charlotte, North Carolina, October 29-30, 1981).

    ERIC Educational Resources Information Center

    Martin, Mary P., Ed.; Staman, E. Michael, Ed.

    Proceedings of a 1981 joint conference sponsored by the Southern Association for Institutional Research (SAIR) and the North Carolina Association for Institutional Research are presented. The conference theme was the practice of institutional research. Contents include preconference workshop reports, speeches, abstracts of papers, and reports of…

  19. The Characteristics, Roles and Functions of Institutional Research Professionals in the Southern Association for Institutional Research.

    ERIC Educational Resources Information Center

    Harrington, Charles; Chen, HongYu

    A study was done on the variation in characteristics, roles, and functions of institutional research professionals affiliated with the Southern Association for Institutional Research (SAIR). The study examined professional role identity, location of offices in the organizational hierarchy, breadth of institutional research activities undertaken,…

  20. Information Management for a Large Multidisciplinary Project

    NASA Technical Reports Server (NTRS)

    Jones, Kennie H.; Randall, Donald P.; Cronin, Catherine K.

    1992-01-01

    In 1989, NASA's Langley Research Center (LaRC) initiated the High-Speed Airframe Integration Research (HiSAIR) Program to develop and demonstrate an integrated environment for high-speed aircraft design using advanced multidisciplinary analysis and optimization procedures. The major goals of this program were to evolve the interactions among disciplines and promote sharing of information, to provide a timely exchange of information among aeronautical disciplines, and to increase the awareness of the effects each discipline has upon other disciplines. LaRC historically has emphasized the advancement of analysis techniques. HiSAIR was founded to synthesize these advanced methods into a multidisciplinary design process emphasizing information feedback among disciplines and optimization. Crucial to the development of such an environment are the definition of the required data exchanges and the methodology for both recording the information and providing the exchanges in a timely manner. These requirements demand extensive use of data management techniques, graphic visualization, and interactive computing. HiSAIR represents the first attempt at LaRC to promote interdisciplinary information exchange on a large scale using advanced data management methodologies combined with state-of-the-art, scientific visualization techniques on graphics workstations in a distributed computing environment. The subject of this paper is the development of the data management system for HiSAIR.

  1. The Response of the Institution to External Forces: Proactive or Reactive? Conference Proceedings of the Southern Association for Institutional Research (Virginia Beach, Virginia, October 30-November 1, 1985).

    ERIC Educational Resources Information Center

    Orahood, Mary Alyce, Ed.

    The proceedings of the 1985 conference of the Southern Association for Institutional Research (SAIR) is presented. The focus was preparing colleges to anticipate and respond to the demand of accrediting bodies, federal agencies, and state legislatures. Contents include: a conference agenda; a keynote address, summaries of pre-conference workshops,…

  2. Predictability and Ensemble Modeling of the Space-Atmosphere Interaction Region

    NASA Astrophysics Data System (ADS)

    Matsuo, T.; Fuller-Rowell, T. J.; Akmaev, R. A.; Wang, H.; Fang, T. W.; Ide, K.; Kleist, D. T.; Whitaker, J. S.; Yue, X.; Codrescu, M.; Richmond, A. D.; Immel, T. J.; Anderson, B. J.; Paxton, L. J.; Liu, J. Y.

    2014-12-01

    The Space-Atmosphere Interaction Region (SAIR), encompassing the mesosphere, thermosphere and ionosphere, is an intersection between geospace and the Earth's atmosphere, and is exposed to vacillating conditions of both space and terrestrial weather. Recent observational and modeling studies have revealed clear reaches of terrestrial weather far beyond the mesosphere lower-thermosphere region into the topside ionosphere. At the same time, the region lends itself to forcing originating from the Sun and solar-wind magnetosphere interactions. The predictability of the SAIR is a fundamental question in Heliophysics, and calls for a paradigm shift from a deterministic to a probabilistic modeling framework. To meet with this contemporary modeling and simulation challenge, we will systematically compare and combine ensemble simulations of a comprehensive whole atmosphere model, coupled with an ionosphere and plasmasphere model called the Integrated Dynamics in Earth's Atmosphere (IDEA) with global Earth and geospace observations. Building on the National Weather Service's operational ensemble forecasting and data assimilation systems as well as our earlier efforts, we will construct an ensemble forecasting and data assimilation system that will ultimately be capable of assimilating observations from the ground to SAIR. We will present the project overview along with some initial results from our new interdisciplinary initiatives.

  3. OASIS 1.0: Very Large-Aperture High-Power Lidar for Exploring Geospace

    NASA Astrophysics Data System (ADS)

    Chu, X.; Smith, J. A.; Chen, C.; Zhao, J.; Yu, Z.; Gardner, C. S.

    2015-12-01

    A new initiative, namely OASIS (the Observatory for Atmosphere Space Interaction Studies), has called for a very large-aperture high-power (VLAHP) lidar as its first step forward to acquire the unprecedented measurement capabilities for exploring the space-atmosphere interaction region (SAIR). Currently, there exists a serious observational gap of the Earth's neutral atmosphere above 100 km. Information on neutral winds and temperatures and on the plasma-neutral coupling in the SAIR, especially between 100 and 200 km, is either sparse or nonexistent. Fully exploring the SAIR requires measurements of the neutral atmosphere to complement radar observations of the plasma. Lidar measurements of neutral winds, temperatures and species can enable these explorations. Many of these topics will be addressed with the VLAHP lidar. Discoveries of thermospheric neutral Fe, Na and K layers up to nearly 200 km at McMurdo, Antarctica and other locations on Earth, have opened a new door to observing the neutral thermosphere with ground-based instruments. These neutral metal layers provide the tracers for resonance Doppler lidars to directly measure the neutral temperatures and winds in the thermosphere, thus enabling the VLAHP lidar dream! Because the thermospheric densities of these metal atoms are many times smaller than the layer peak densities near 90 km, high power-aperture product lidars, like the VLAHP lidar, are required to derive scientifically useful measurements. Furthermore, several key technical challenges for VLAHP lidar have been largely resolved in the last a few years through the successful development of Fe and Na Doppler lidars at Boulder. By combining Rayleigh and Raman with resonance lidar techniques and strategically operating the VLAHP lidar next to incoherent scatter radar and other complementary instruments, the VLAHP lidar will enable new cutting-edge exploration of the geospace. These new concepts and progresses will be introduced in this paper.

  4. A Web Application For Visualizing Empirical Models of the Space-Atmosphere Interface Region: AtModWeb

    NASA Astrophysics Data System (ADS)

    Knipp, D.; Kilcommons, L. M.; Damas, M. C.

    2015-12-01

    We have created a simple and user-friendly web application to visualize output from empirical atmospheric models that describe the lower atmosphere and the Space-Atmosphere Interface Region (SAIR). The Atmospheric Model Web Explorer (AtModWeb) is a lightweight, multi-user, Python-driven application which uses standard web technology (jQuery, HTML5, CSS3) to give an in-browser interface that can produce plots of modeled quantities such as temperature and individual species and total densities of neutral and ionized upper-atmosphere. Output may be displayed as: 1) a contour plot over a map projection, 2) a pseudo-color plot (heatmap) which allows visualization of a variable as a function of two spatial coordinates, or 3) a simple line plot of one spatial coordinate versus any number of desired model output variables. The application is designed around an abstraction of an empirical atmospheric model, essentially treating the model code as a black box, which makes it simple to add additional models without modifying the main body of the application. Currently implemented are the Naval Research Laboratory NRLMSISE00 model for neutral atmosphere and the International Reference Ionosphere (IRI). These models are relevant to the Low Earth Orbit environment and the SAIR. The interface is simple and usable, allowing users (students and experts) to specify time and location, and choose between historical (i.e. the values for the given date) or manual specification of whichever solar or geomagnetic activity drivers are required by the model. We present a number of use-case examples from research and education: 1) How does atmospheric density between the surface and 1000 km vary with time of day, season and solar cycle?; 2) How do ionospheric layers change with the solar cycle?; 3 How does the composition of the SAIR vary between day and night at a fixed altitude?

  5. The T. Mort. Chaplaincy at ground zero: presence and privilege on holy ground.

    PubMed

    Swain, Storm

    2011-09-01

    Drawing on interviews with the chaplains and archival material from Disaster Chaplaincy Services--NY, this article discusses the formation of the chaplaincy at the Temporary Mortuary at Ground Zero after the terrorist attacks on September 11, 2001. It describes the initial chaplaincy response in New York by local clergy and the SAIR team of the American Red Cross. The first 6 weeks of chaplaincy at Ground Zero are explored highlighting the significant contributions of the Archdiocese of New York and Episcopal Diocese of New York out of St. Paul's Chapel. The mission and impact of the Temporary Mortuary chaplains' ministry of presence and blessing is discussed with some final reflections for the future of Disaster Chaplaincy. PMID:21850560

  6. Improved design of a passive millimeter-wave synthetic aperture interferometric imager for indoor applications

    NASA Astrophysics Data System (ADS)

    Yao, Xianxun; Liu, Kai; Hu, Anyong; Miao, Jungang

    2015-10-01

    A passive millimeter-wave imager prototype based on synthetic aperture interferometric radiometer (SAIR) technique is developing at Beihang University. It is designed for concealed contraband detection on human body in indoor environment at video imaging rate. The radiometric sensitivity requirements have been discussed in details, and the performance requirements of the digital processing subsystem have been analytically determined. A novel distributed digital correlator array architecture is proposed by using FPGA array, which results in reduction of hardware complexity and cost of the digital processing subsystem. In the proposed architecture, multistage pipeline technique is introduced for the reuse of logical resource that in turn results in decrease of transmission rate requirements for each FPGA, so that the feasibility of the digital processing subsystem can be greatly enhanced.

  7. A New 2-Dimensional Millimeter Wave Radiation Imaging System Based on Finite Difference Regularization

    NASA Astrophysics Data System (ADS)

    Zhu, Lu; Liu, Yuanyuan; Chen, Suhua; Hu, Fei; Chen, Zhizhang (David)

    2015-04-01

    Synthetic aperture imaging radiometer (SAIR) has the potential to meet the spatial resolution requirement of passive millimeter remote sensing from space. A new two-dimensional (2-D) imaging radiometer at millimeter wave (MMW) band is described in this paper; it uses a one-dimensional (1-D) synthetic aperture digital radiometer (SADR) to obtain an image on one dimension and a rotary platform to provide a scan on the second dimension. Due to the ill-posed inverse problem of SADR, we proposed a new reconstruction algorithm based on Finite Difference (FD) regularization to improve brightness temperature images. Experimental results show that the proposed 2-D MMW radiometer can give the brightness temperature images of natural scenes and the FD regularization reconstruction algorithm is able to improve the quality of brightness temperature images.

  8. Inventario mundial de la calidad del carbon mineral (WoCQI) [The world coal quality inventory (WoCQI)

    USGS Publications Warehouse

    Finkelman, R.B.; Lovern, V.S.

    2001-01-01

    Los oficiales encargados de la politica comercial de cada pais requieren informacion clara y precisa sobre el recurso del carbon mineral, particularmente sobre sus propiedades y caracteristicas, para tomar decisiones bien fundamentadas con respecto al mejor uso de los recursos naturales, necesidades de importacion y oportunidades de exportacion, objetivos de politica interna y externa, oportunidades de transferencia tecnologica, posibilidades de inversion externa, estudios ambientales y de salud, y asuntos relacionados con el uso de productos secundarios y su disposicion.

  9. Lidar Observations and Numerical Modeling Studies of Thermospheric Metal Layers and Solar Effects on Mesospheric Fe Layers

    NASA Astrophysics Data System (ADS)

    Yu, Zhibin

    By blocking extreme hazards from space and regulating radio wave propagation, the space-atmosphere interaction region (SAIR) -- our window to open space -- is essential for life on Earth and modern society. However, the physical and chemical processes governing the SAIR are not sufficiently understood due to the woefully incomplete measurements of neutral properties in this region, especially between 100 and 200 km altitude. Thermospheric Fe layers extending from ~70 to 170 km discovered by the Fe Boltzmann lidar at McMurdo, Antarctica have opened a new door to observing the neutral thermosphere and mesosphere. This thesis is aimed at revealing such new discoveries, and advancing our understanding of the thermospheric Fe layer formation, through analyzing the lidar data collected by the author in Antarctic winter and developing the first thermospheric Fe/Fe+ model. A one-dimensional high-latitude Fe/Fe+ model based on physical and chemical first principles has been developed to quantitatively explore the source, formation and evolution of thermospheric Fe layers. We demonstrate that the observed Fe layers are produced by neutralization of converged Fe+, mainly through the direct electron-Fe+ recombination. We find that the polar electric field is capable of uplifting Fe+ ions from the main deposition region into the thermosphere, supplying the source of neutral Fe. Both gravity-wave-induced wind shears and the polar electric field can converge Fe+ layers. Vertical wind plays a key role in transporting Fe to form the observed wave structures, but horizontal divergence can largely offset the vertical convergence effects. These theoretical studies lay the foundation for exploring the thermosphere by resonance lidars. The diurnal variations of Fe layers in the mesopause region are characterized with our lidar observations at McMurdo. A new finding is the solar effect on the Fe layer bottomside --- daytime downward extension and nighttime upward contraction. We explain

  10. High-definition computed tomography for coronary artery stents: image quality and radiation doses for low voltage (100 kVp) and standard voltage (120 kVp) ECG-triggered scanning.

    PubMed

    Lee, Ji Won; Kim, Chang Won; Lee, Han Cheol; Wu, Ming-Ting; Hwangbo, Lee; Choo, Ki Seok; Kim, June Hong; Lee, Ki-Nam; Kim, Jin You; Jeong, Yeon Joo

    2015-06-01

    The noninvasive assessment of coronary stents by coronary CT angiography (CCTA) is an attractive method. However, the radiation dose associated with CCTA remains a concern for patients. The purpose of this study is to compare the radiation doses and image qualities of CCTA performed using tube voltages of 100 or 120 kVp for the evaluation of coronary stents. After receiving institutional review board approval, 53 consecutive patients with previously implanted stents (101 stents) underwent 64-slice CCTA. Patients were divided into three different protocol groups, namely, prospective ECG triggering at 100 kVp, prospective ECG triggering at 120 kVp, or retrospective gating at 100 kVp. Two reviewers qualitatively scored the quality of the resulting images for coronary stents and determined levels of artificial lumen narrowing (ALN), stent lumen attenuation increase ratio (SAIR), image noise, and radiation dose parameters. No significant differences were found between the three protocol groups concerning qualitative image quality or SAIR. Coronary lumen attenuation and in-stent attenuation of 100 kVp prospective CCTA (P-CCTA) were higher than in the 120 kVp P-CCTA protocol (all Ps < 0.001). Mean ALN was significantly lower for 100 kVp P-CCTA than for 100 kVp retrospective CCTA (R-CCTA, P = 0.007). The mean effective radiation dose was significantly lower (P < 0.001) for 100 kVp P-CCTA (3.3 ± 0.4 mSv) than for the other two protocols (100 kVp R-CCTA 6.7 ± 1.0 mSv, 120 kVp P-CCTA 4.6 ± 1.2 mSv). We conclude that the use of 100 kVp P-CCTA can reduce radiation doses for patients while maintaining the imaging quality of 100 kVp R-CCTA and 120 kVp P-CCTA for the evaluation of coronary stents. PMID:26022439

  11. The modern human colonization of western Eurasia: when and where?

    NASA Astrophysics Data System (ADS)

    Hublin, Jean-Jacques

    2015-06-01

    Dating the timing of the replacement of local Neandertal populations by modern humans in western Eurasia at the dawn of the Upper Palaeolithic remains challenging due to the scarcity of the palaeontological evidence and to the complexity of the archaeological record. Furthermore, key specimens have been discovered in the course of excavations that unfortunately did not meet today's archaeological standards. The importance of site-formation processes in the considered time period makes it sometimes difficult to precisely assign fragmentary remains a posteriori to distinct techno-complexes. The improvements in dating methods have however allowed for the clarification of many chronological issues in the past decade. Archaeological and palaeontological evidence strongly suggest that the initial modern colonization of eastern Europe and central Asia should be related to the spread of techno-complexes assigned to the Initial Upper Palaeolithic. This first expansion may have started as early as 48 ka cal BP. The earliest phases of the Aurignacian complex (Protoaurignacian and Early Aurignacian) seem to represent another modern wave of migrations, starting in the Levant area. The expansion of this techno-complex throughout Europe completed the modern colonization of the continent. The interpretation of a third group of industries referred to as "transitional assemblages" in western and central Europe is much debated. At least in part, these assemblages might have been produced by Neandertal groups that may have survived until c. 41 ka cal BP, according to the directly dated Neandertal specimens of Saint-Césaire (France) and Spy (Belgium).

  12. Possible Interbreeding in Late Italian Neanderthals? New Data from the Mezzena Jaw (Monti Lessini, Verona, Italy)

    PubMed Central

    Condemi, Silvana; Mounier, Aurélien; Giunti, Paolo; Lari, Martina; Caramelli, David; Longo, Laura

    2013-01-01

    In this article we examine the mandible of Riparo Mezzena a Middle Paleolithic rockshelter in the Monti Lessini (NE Italy, Verona) found in 1957 in association with Charentian Mousterian lithic assemblages. Mitochondrial DNA analysis performed on this jaw and on other cranial fragments found at the same stratigraphic level has led to the identification of the only genetically typed Neanderthal of the Italian peninsula and has confirmed through direct dating that it belongs to a late Neanderthal. Our aim here is to re-evaluate the taxonomic affinities of the Mezzena mandible in a wide comparative framework using both comparative morphology and geometric morphometrics. The comparative sample includes mid-Pleistocene fossils, Neanderthals and anatomically modern humans. This study of the Mezzena jaw shows that the chin region is similar to that of other late Neanderthals which display a much more modern morphology with an incipient mental trigone (e.g. Spy 1, La Ferrassie, Saint-Césaire). In our view, this change in morphology among late Neanderthals supports the hypothesis of anatomical change of late Neanderthals and the hypothesis of a certain degree of interbreeding with AMHs that, as the dating shows, was already present in the European territory. Our observations on the chin of the Mezzena mandible lead us to support a non abrupt phylogenetic transition for this period in Europe. PMID:23544098

  13. [Community ecology of metazoan parasites of Cyphocharax gilbert (Quoy e Gaimard, 1824) (Characiformes: Curimatidae) from Guandu river, State of Rio de Janeiro, Brazil].

    PubMed

    Abdallah, Vanessa D; de Azevedo, Rodney K; Luque, José L

    2005-01-01

    Sixty specimens of Sairú Cyphocharax gilbert (Quoy and Gaimard, 1824) from River Guandu, (22 degrees 48'32'S, 43 degrees 37'35''"W), State of Rio de Janeiro, Brazil were studied for their metazoan parasites during May 2004 and February 2005. A total of seven species of metazoan parasites were collected and identified: Sphinctero- diplostomum musculosum (metacercariae), Diplostomum (A.) compactum (metacercariae), Zonocotyloides haroltravassosi, Cosmoxynemoides aguirrei, Travnema araujoi, Raphidascaris sp. (larval) and Placobdella sp. Sphincterodiplostomum musculosum (Diplostomidae) founded in the eyes, was the more prevalent (40%) with highest mean intensity value (11.2). The nematodes C. aguirrei and T. araujoi (Pharyngodonidae) showed prevalence higher than 10%. Only S. musculosum showed significant correlation between the host total length and the parasite abundance. The parasite species richness showed a mean value of 0.9 + 0.88 (0-3). The evaluation of the effect of host sex on parasite prevalence and abundance not showed significant results. The metazoan parasite community of C. gilbert is characterized by the low species diversity and for dominance of species with low values of prevalence. PMID:16445872

  14. From Bretonneau to therapeutic antibodies, from specificity to specific remedies, Saint-Cyr-Sur-Loire, France, November 19, 2012

    PubMed Central

    Marchand, Claire; Nouat, Romaric; Watier, Hervé

    2013-01-01

    Held on November 19, 2012 in Saint-Cyr-sur-Loire, France, the symposium “From Bretonneau to therapeutic antibodies, from specificity to specific remedies” focused on the historical development of antibodies as therapeutics, with an emphasis on the seminal work of the French physician Pierre-Fidèle Bretonneau (1778–1862). The morning session was devoted to discussion of the evolution of the concept of specificity in medicine, which started with an epistemological definition. The contributions of Bretonneau to the emergence of the concept of specificity, notably with his studies on diphtheria, and the subsequent development of antidiphtheric serotherapy in Europe during the period 1894–1898 were then presented in detail. The afternoon session began with a presentation on the role of French physiologists during the years 1860–1890 in establishing the basic concepts of specific immunity and the principles of serotherapy. The history of antivenom serotherapy, particularly its discovery by Césaire Phisalix, and the development of antilymphocyte globulins as successful transplantation drugs were then discussed. The symposium ended with the inauguration of a stele representing Bretonneau, who lived in Saint-Cyr-sur-Loire and died 150 y ago. PMID:23924799

  15. Paths to the discovery of antivenom serotherapy in France.

    PubMed

    Bochner, Rosany

    2016-01-01

    The current study presents a descriptive chronological survey of the articles published by Césaire Auguste Phisalix and Albert Calmette on snake poison, with the aim of shedding a light on the areas of research and reasoning followed by these scientists, leading up to their simultaneous discovery of antivenom serotherapy in 1894. The path taken by Phisalix is revealed in 15 articles that demonstrate the motivation of a naturalist and the way he confronted the puzzle of immunity against snake venom. In the case of Calmette, two articles preceded the discovery; microbiology was his theoretical base and the Pasteurian spirit of solving health problems his driving force. These two researchers followed distinct paths, mobilized by different motivations, but produced one single result. It is incontestable that the discovery of antivenom serotherapy was the work of two groups of researchers who deserve equal recognition, but who, in fact, did not receive it. Following the discovery both Calmette and Phisalix returned to their previous motivations. Calmette put the discovery into practice and began to produce antivenom serum in Lille. He came to be generally considered as the sole discoverer of antivenom serotherapy and was the recipient of a number of prestigious prizes. Phisalix, on the other hand, received little recognition and returned to his original interests, devoting himself to research on natural immunity. In Brazil, the discovery of antivenom serum therapy had a profound impact on the work of Vital Brazil Mineiro da Campanha, a researcher known worldwide for his scientific discoveries and for the evidence of the specificity of antivenom serums. PMID:27279829

  16. The Châtelperronian conundrum: Blade and bladelet lithic technologies from Quinçay, France.

    PubMed

    Roussel, M; Soressi, M; Hublin, J-J

    2016-06-01

    The discovery of an almost complete Neanderthal skeleton in a Châtelperronian context at Saint-Césaire 35 years ago changed our perspective on the beginning of the Upper Paleolithic in western Europe. Since then, the Châtelperronian has generally been considered a "transitional" industry rather than an Upper or a Middle Paleolithic industry because of its chronological position, and the association of Neanderthal remains with blades, bone tools and personal ornaments. Several competing hypotheses have been proposed to explain the association between Neanderthals and these types of artefacts including post-depositional mixing, acculturation from anatomically modern human populations, or an independent technological evolution by local Neanderthal populations. Quinçay Cave is the only Châtelperronian site where personal ornaments have been found that does not contain an overlying Upper Paleolithic layer. This means that the post-depositional mixing of later elements into the Châtelperronian may not be used as an explanation for the presence of these materials. We report here on a detailed technological analysis of lithic artefacts from the three Châtelperronian layers at Quinçay Cave. We compare our results with the technology of Mousterian blade industries dating to OIS (oxygen isotope stage) 5, the Mousterian of Acheulian Tradition type B, and the Proto-Aurignacian. We show that the Châtelperronian is sufficiently divergent from the Middle Paleolithic to be classified as a fully Upper Paleolithic industry, with a focus on blade and bladelet production. We also show that the Quinçay Châtelperronian includes retouched bladelets that resemble those found in the Proto-Aurignacian, but were produced in a different manner. We argue that a technological convergence cannot account for these behaviors, since the specific type of retouched bladelet associated with the Châtelperronian was also regularly used by Proto-Aurignacian of neighboring regions. We suggest

  17. [In Process Citation].

    PubMed

    Hernández-Morante, Juan José; Galindo-Muñoz, Joaquín Santiago; Barberá-Ortega, María Del Carmen

    2016-01-01

    Introducción: actualmente el tratamiento dietético de la obesidad no suele ser efectivo en muchos casos, probablemente porque se diseña fundamentalmente teniendo en cuenta el gasto energético mientras que otros aspectos relevantes, como los ritmos de hambre/saciedad, apenas son considerados. Los nuevos dispositivos móviles (smartphones) podrían ayudar a este respecto. Objetivo: desarrollar una aplicación para smartphones con el fin de analizar variables subjetivas relacionadas con el apetito de forma precisa y fiable.  Métodos: se analizaron las sensaciones subjetivas de apetito de 15 voluntarios sanos mediante dos métodos: papel-lápiz (P-P) y una nueva aplicación para smartphones. Las sensaciones de apetito se analizaron cada 30 minutos durante 4 horas en dos situaciones: desayuno alto en carbohidratos (HC) y alto en grasas (HF). Además, los sujetos completaron la aplicación cada 30 minutos en condiciones ambientales. Resultados: los datos derivados del ANOVA indican que no existieron diferencias respecto al método (P-P vs. aplicación) o comida (HC vs. HF) (p > 0.05) para las puntuaciones de hambre, deseo de comer y saciedad. Los coeficientes de regresión mostraron una elevada concordancia (R 2 : 0.94-0.98). El test de Bland-Altman también reveló una alta reciprocidad entre ambos métodos. Además, la aplicación fue capaz de medir las variaciones subjetivas de apetito en condiciones ambientales. Conclusión: la aplicación para smartphones fue capaz de determinar de forma fiable y precisa las variables subjetivas de apetito tanto en condiciones de laboratorio como ambientales, lo que confirma la idoneidad de esta aplicación para llevar a cabo futuros estudios en los que se evalúe la regulación del apetito en humanos. PMID:27238807

  18. Estudio multiespectral del remanente de supernova W 28

    NASA Astrophysics Data System (ADS)

    Dubner, G.; Velázquez, P.; Castelletti, G.

    Se presentan observaciones en continuo de radio con muy alta resolución angular y sensibilidad del remanente de supernova (RSN) W28. Las observaciones fueron realizadas con el interferómetro Very Large Array (Estados Unidos), en las configuraciones C y D, en 1415 y 324 MHz. Por la gran extensión de este remanente (diámetro ~ 1o), las observaciones en 1415 MHz se realizaron en modo mosaico, combinando 48 apuntamientos diferentes en una única imagen. En ambas frecuencias los datos se procesaron con el agregado de observaciones de menor resolución angular, a fin de recuperar información en todas las frecuencias espaciales y obtener estimaciones precisas de densidad de flujo. Las imágenes resultantes muestran por primera vez la presencia de extensiones con forma de arco, cuya naturaleza se investiga. Las observaciones en radio se comparan con una imagen óptica de W28, y con la emisión en rayos X, observada con el satélite ROSAT. Este remanente muestra una clara morfología híbrida, tipo cáscara en frecuencias de radio y de centro lleno en las bandas óptica y de rayos X blandos.

  19. Modelo analítico del efecto de PRS sobre satélites GPS

    NASA Astrophysics Data System (ADS)

    Meza, A.; Brunini, C.; Usandivaras, J. C.

    El sistema GPS (Global Position System) es, hoy en día, la herramienta de navegación y posicionamiento más potente y lo será sin duda en la próxima década. Gran parte de su valiosa utilidad se debe a la alta precisión que permite lograr y ésta, a su vez, depende, entre otras causas, de la precisión con que se conocen las órbitas de los satélites. La presión de radiación solar (PRS) fija el límite de la precisión con que pueden calcularse en la actualidad las efemérides satelitarias. El objetivo de este trabajo es proponer una mejor resolución de este fenómeno. El modelo analítico aquí presentado, se basa en el análisis del comportamiento de los residuos de un ajuste por mínimos cuadrados en el que se utiliza el modelo de PRS propuesto por Beutler. El mismo consiste en un modelo determinista del fenómeno con dos parámetros libres. Los resultados obtenidos ponen de manifiesto que, aún después de aplicar dichos parámetros, prevalecen en los residuos efectos semidiurnos en las componentes radial,tangencial y normal. Estos resultados obtenidos se comparan con los de un trabajo desarrollado por el Instituto de Berne (Beutler et al., 1994), en el que se utilizaron como pseudo-observaciones las órbitas precisas del IGS (CODE). El intervalo de integración escogido por este centro fueron las semanas 680 y 681. En resumen se tienen arcos de 14 días para todos los satélites, donde las efemérides precisas de los mismos para los 14 días fueron utilizados como pseudo-observaciones. El modelo de fuerza que empleó dicho centro fue básicamente el tradicional en lo que respecta al modelo de las fuerzas gravitacionales, y para la PRS utilizo el modelo standard de Beutler. Los parámetros de este modelo junto con las 6 condiciones iniciales (posición y velocidad) fueron ajustados por el método general de mínimos cuadrados. Los residuos en la componente radial, tangencial y normal, para los satélites con un buen comportamiento, presentan una

  20. [In Process Citation].

    PubMed

    Calleja Fernández, Alicia; Vidal Casariego, Alfonso; Cano Rodríguez, Isidoro; Ballesteros Pomar, María D

    2016-01-01

    Introducción: la cuantificación y registro de la ingesta alimentaria del paciente hospitalizado es clave dentro del plan de cuidado nutricional. Objetivo: evaluar la validez de un cuestionario semicuantitativo de valoración del consumo comparado con una técnica de registro de alimentos por observación y pesada de los platos incluidos en la dieta hospitalaria. Métodos: estudio transversal realizado en condiciones de práctica clínica habitual. Las técnicas de valoración del consumo que se compararon fueron un registro por doble pesada y un cuestionario semicuantitativo por observación de la ingesta de cinco categorías (todo [> 80%], casi todo [80-60%], la mitad [60-40%], casi nada [40-20%] o nada [< 20%]), ambas realizadas por un dietista-nutricionista. La comparación entre ambas herramientas fue realizada con el índice kappa con ponderación cuadrática e intervalo de confianza del 95%. Resultados: fueron realizadas un total de 1.980 valoraciones. Se observó con el cuestionario semicuantitativo que en el 50% de los casos se ingirió todo, en el 19% casi todo, en el 13% la mitad, en el 9% menos de la mitad y en el 9% nada. La mediana de la ingesta por doble pesada de alimentos fue de 76,8 (RIC 45,8)%. Se observó que existió un acuerdo satisfactorio entre la técnica de doble pesada y la valoración visual del consumo con un valor κ = 0,907 (IC 95% 0,894-0,925). Conclusión: la escala visual empleada en este estudio permite cuantificar la ingesta real del paciente de forma precisa y adecuada por personal cualificado. PMID:27238794

  1. Análisis del futuro marco de referencia internacional

    NASA Astrophysics Data System (ADS)

    Cionco, G. R.; Arias, E. F.

    La técnica de interferometría de muy larga línea de base (VLBI) se aplica hoy a la astrometría para el cálculo de posiciones precisas de radiofuentes extragalácticas. Por tratarse de objetos lejanos, sus movimientos propios aparentes pueden considerarse nulos; esta propiedad hace que los catálogos de radiofuentes extragalácticas VLBI constituyan la mejor materialización de un sistema de referencia celeste inercial definido cinemáticamente. La Unión Astronómica Internacional (IAU) recomendó la adopción de un nuevo sistema de referencia celeste internacional materializado por las coordenadas ecuatoriales de objetos extragalácticos observados con le técnica VLBI. Para superar la precisión astrométrica actual es necesaria una mejora en la modelización de aquellos fenómenos que pueden introducir desviaciones sistemáticas en el marco de referencia celeste. El objetivo de este trabajo es poner de manifiesto las sistematicidades presentes en los distintos marcos de referencia elaborados con el próposito de materializar el nuevo sistema de referencia celeste de la IAU. Para la comparación de los distintos marcos de referencia se propone un modelo de tres rotaciones diferenciales más un término lineal que procura absorber los efectos sistemáticos presentes en las coordenadas. Se analiza igualmente la estabilidad de la solución cuando se utilizan distintos conjuntos de objetos de definición.

  2. El Sistema de Referencia Celeste convencional de la IAU

    NASA Astrophysics Data System (ADS)

    Arias, E. F.

    La Unión Astronómica Internacional (IAU) recomendó la adopción de un nuevo sistema de referencia celeste baricéntrico cuyo plano fundamental y origen de ascensiones rectas estén próximos, respectivamente, al ecuador y equinoccio dinámicos J2000.0. El nuevo sistema de referencia estará materializado por las posiciones J2000.0 de radiofuentes extragalácticas determinadas con la técnica de interferometría de larga línea de base (VLBI). El Working Group on Reference Frames de la IAU (WGRF) decidió adoptar (Grasse, 1995) al sistema de referencia celeste extragaláctico del Servicio Internacional de la Rotación Terrestre (IERS) como futuro sistema de referencia celeste convencional bajo el nombre International Celestial Reference System (ICRS) y encomendó su mantenimiento futuro al IERS. El marco de referencia que materializará al ICRS contiene posiciones precisas J2000.0 de más de 600 radiofuentes extragalácticas. Las coordenadas fueron ajustadas en una única solución VLBI en la cual se incluyeron todas las observaciones realizadas hasta octubre de 1995 con la técnica de adquisición de datos VLBI Mark III. Para minimizar los errores sistemáticos que pueden afectar la calidad del marco de referencia se introdujeron mejoras sustanciales en la modelización y en la selección de datos. Un subconjunto de objetos del marco de referencia se utilizó para referir las posiciones estelares determinadas con el satélite astrométrico Hipparcos al ICRS.

  3. Teorí­as de primer y segundo orden sobre el potencial de ciertas figuras de equilibrio de cuerpos celestes

    NASA Astrophysics Data System (ADS)

    Gumbau, Manuel Forner

    2010-11-01

    Uno de los problemas que aborda la Mecánica Celeste es la determinación de las figuras de equilibrio de los cuerpos celestes. Para investigar su solución mediante métodos directos, se precisa evaluar el potencial generado por su autogravitación, el generado por su fuerza centrí­fuga y el generado por la fuerza de atracción entre los cuerpos. Los métodos clásicos de Finlay y Kopal que afrontan estos problemas, para determinar el potencial autogravitatorio en las configuraciones de equilibrio, emplean desarrollos en serie de los potenciales interior y exterior del potencial autogravitatorio. Estos métodos incurren en el error de suponer la convergencia en capas donde resulta cuestionable dicha convergencia para estos desarrollos en serie. En este trabajo se han elaborado unos algoritmos que contemplan toda la casuí&stica y que permiten una manipulación efic iente del producto de polinomios de Legendre, del producto de funciones asociada s de Legendre y del producto de armónicos esféricos como combinacióon lineal de ellos mismos, respectivamente. Se han obtenido, para primer y segundo orden en las amplitudes, los desarrollos correctos para los potencial es interior y exterior del potencial autogravitatorio para configuraciones de equilibrio aisladas, y , en primer orden de amplitudes, los mismos potenciales para los sistemas binarios próximos. Se ha elaborado un método analítico, en primer orden respecto de las amplitudes, para la determinación del potencial de marea en sistemas binarios próximos en el cual se manifiesta la forma de la componente secundaria del sistema

  4. Variaciones seculares de período en las RR Lyrae de ω~Centauri

    NASA Astrophysics Data System (ADS)

    Marraco, H. G.; Milesi, G. E.

    Utilizando 689 observaciones de 35 estrellas RR Lyrae del cúmulo globular ω Centauri hemos obtenido nuevas determinaciones de sus períodos y sus correspondientes variaciones seculares. Las observaciones fueron obtenidas de la literatura con la excepción de un grupo 66 determinaciones que se presentan por vez primera aquí. Utilizando el parámetro testigo σ descripto en Marraco & Muzzio (Publ. Astron. Soc. Pacific 92, 700, 1980), hemos realizado un ajuste bidimensional en P y β (donde β es la variación secular del período). Con este fin la totalidad de las 689 observaciones fueron llevadas a un sistema fotométrico común. Para esto se realizó un cuidadoso análisis de los numerosos errores en la identificación de las estrellas de las series de comparación. Los resultados de los ajustes bidimensionales fueron analizados utilizando técnicas de procesamiento de imágenes. Con este fin el parámetro de ajuste σ fue representado como función de P y β. En las imágenes resultantes se buscaron los mínimos y al menor de ellos se lo aceptó como período instantáneo verdadero y su variación secular β. La determinación precisa de cada parámetro se realizó mediante ajuste de gaussianas y se determinaron sus errores. A modo de ejemplo la variable #8 fue analizada en una matriz de 501 × 501 elementos representando el parámetro σ para valores comprendidos entre 0,521034 < P < 0,521534 dias y -150×10-10 < β < +150×10-10 dias/dia. El mejor período instantáneo (correspondiente a la época DJ=2.426.908) y su variación secular son P = 0,5212859±0,0000001 días y β 14,012±,010×10-10 días/día respectivamente. Con estos valores el parámetro testigo resulta σ= 0,127 . Si no se tiene en cuenta la variación secular del período y se busca aquél de mejor ajuste para β = 0, se obtiene P = 0,5212960 días, pero entonces el parámetro de ajuste resulta tan alto como σ = 0,23 .

  5. Variação temporal do gradiente radial de o/h a partir de uma amostra de nebulosas planetárias

    NASA Astrophysics Data System (ADS)

    Maciel, W. J.; Costa, R. D. D.; Uchida, M. M. M.

    2003-08-01

    Gradientes radiais de abundância são observados no disco de nossa Galáxia e também em outras galáxias espirais. No caso da Galáxia, o principal problema relativo aos gradientes é sua variação temporal, que constitui um dos principais vínculos aos modelos de evolução química da Galáxia. As nebulosas planetárias são particularmente interessantes no estudo dos gradientes e suas variações, tanto espaciais como temporais. São objetos brilhantes, podendo ser observadas a grandes distâncias, e têm abundâncias relativamente precisas de diversos elementos químicos. Além disso, sendo originadas de estrelas com massas entre 0.8 e 8 massas solares na sequência principal, incluem objetos com idades e populações diferentes, o que as torna especialmente interessantes ao estudo da variação temporal dos gradientes. Neste trabalho, apresentamos resultados recentes sobre a variação temporal do gradiente de O/H a partir de uma amostra contendo cerca de 200 nebulosas, para as quais obtivemos distâncias por métodos estatísticos. As abundâncias foram parcialmente obtidas a partir de observações em Itajubá e La Silla, sendo as restantes obtidas da literatura. Os resultados mostram, pela primeira vez, evidências de um achatamento do gradiente de O/H, de -0.11 dex/kpc para -0.06 dex/kpc nos últimos 9 giga-anos ou de -0.08 dex/kpc para -0.06 dex/kpc nos últimos 5 giga-anos. Esses valores apresentam um bom acordo com alguns modelos recentes para a evolução química da Galáxia. (FAPESP/CNPq)

  6. BSSDATA - um programa otimizado para filtragem de dados em radioastronomia solar

    NASA Astrophysics Data System (ADS)

    Martinon, A. R. F.; Sawant, H. S.; Fernandes, F. C. R.; Stephany, S.; Preto, A. J.; Dobrowolski, K. M.

    2003-08-01

    A partir de 1998, entrou em operação regular no INPE, em São José dos Campos, o Brazilian Solar Spectroscope (BSS). O BSS é dedicado às observações de explosões solares decimétricas com alta resolução temporal e espectral, com a principal finalidade de investigar fenômenos associados com a liberação de energia dos "flares" solares. Entre os anos de 1999 e 2002, foram catalogadas, aproximadamente 340 explosões solares classificadas em 8 tipos distintos, de acordo com suas características morfológicas. Na análise detalhada de cada tipo, ou grupo, de explosões solares deve-se considerar a variação do fluxo do sol calmo ("background"), em função da freqüência e a variação temporal, além da complexidade das explosões e estruturas finas registradas superpostas ao fundo variável. Com o intuito de realizar tal análise foi desenvolvido o programa BSSData. Este programa, desenvolvido em linguagem C++, é constituído de várias ferramentas que auxiliam no tratamento e análise dos dados registrados pelo BSS. Neste trabalho iremos abordar as ferramentas referentes à filtragem do ruído de fundo. As rotinas do BSSData para filtragem de ruído foram testadas nos diversos grupos de explosões solares ("dots", "fibra", "lace", "patch", "spikes", "tipo III" e "zebra") alcançando um bom resultado na diminuição do ruído de fundo e obtendo, em conseqüência, dados onde o sinal torna-se mais homogêneo ressaltando as áreas onde existem explosões solares e tornando mais precisas as determinações dos parâmetros observacionais de cada explosão. Estes resultados serão apresentados e discutidos.

  7. Otimização de procedimento de manobra para indução de reentrada de um satélite retornável

    NASA Astrophysics Data System (ADS)

    Schulz, W.; Suarez, M.

    2003-08-01

    Veículos espaciais que retornam à Terra passam por regimes de velocidade e condições de vôo distintos. Estas diferenças dificultam sua concepção aerodinâmica e o planejamento de seu retorno. A partir de uma proposta de um veículo orbital retornável (satélite SARA, em desenvolvimento no IAE/CTA) para realização de experimentos científicos e tecnológicos em ambiente de baixa gravidade, surge a necessidade de realizarem-se estudos considerando-se os aspectos relativos à sua aerodinâmica. Após o lançamento, o veículo deve permanecer em órbita pelo tempo necessário para a condução de experimentos, sendo depois direcionado à Terra e recuperado em solo. A concepção aerodinâmica é de importância para o vôo em suas diversas fases e deve considerar aspectos relativos à estabilização Aerodinâmica e ao arrasto atmosférico, sendo este último de importância crucial na análise do aquecimento a ser enfrentado. A manobra de retorno inclui considerações sobre as condições atmosféricas e dinâmica de reentrada, devendo ser calculada de forma mais precisa possível. O trabalho proposto avalia estudos da dinâmica de vôo de um satélite recuperável considerando aspectos relativos à determinação orbital com GPS, técnica utilizada com sucesso na CONAE, e seu comportamento aerodinâmico em vôo balístico de retorno, com ênfase em sua fase de reentrada atmosférica. Busca-se otimizar a manobra de reentrada de tal forma que a utilização do sistema GPS garanta minimizar a área de impacto com o solo.

  8. El uso de la neuromodulación para el tratamiento del temblor

    PubMed Central

    Bendersky, Damián; Ajler, Pablo; Yampolsky, Claudio

    2014-01-01

    Introducción: El temblor puede ser un desorden incapacitante y el tratamiento de primera línea para estos pacientes es farmacológico. Sin embargo, este tratamiento puede llevar a una reducción satisfactoria del temblor en sólo el 50% de los pacientes con temblor esencial. La talamotomía era el tratamiento de elección para el temblor refractario al tratamiento médico hasta que comenzó a utilizarse la estimulación cerebral profunda (ECP) del núcleo ventral intermedio (Vim) del tálamo. En la actualidad, raramente se realiza la talamotomía. Métodos: Este artículo es una revisión no sistemática de las indicaciones, resultados, parámetros de programación y técnica quirúrgica de la ECP del Vim para el tratamiento del temblor. Resultados: Aunque los resultados clínicos son similares usando la talamotomía o la ECP del Vim, la primera causa más efectos adversos que la última. Además, la ECP puede ser usada bilateralmente, mientras que la talamotomía tiene un alto riesgo de causar disartria cuando se realiza de ambos lados. La ECP del Vim logró una adecuada mejoría del temblor en varias series de pacientes con temblor causado por temblor esencial, enfermedad de Parkinson o esclerosis múltiple. Además del Vim, hay otros blancos que están siendo usados por varios autores, tales como la zona incerta y las radiaciones prelemniscales. Conclusión: La ECP del Vim es un tratamiento útil para el temblor incapacitante refractario al tratamiento médico. Es esencial realizar una precisa selección de pacientes, así como utilizar una técnica quirúrgica correcta. Aún se desconoce el mejor blanco estereotáctico para el temblor, aunque el Vim es el más usado. PMID:25165613

  9. [Not Available].

    PubMed

    Martínez de Victoria, Emilio

    2016-01-01

    El calcio (Ca) es el elemento mineral más abundante en nuestro organismo, ya que forma parte importante del esqueleto y los dientes. Supone alrededor del 2% del peso corporal. Las funciones del calcio son: a) funciones esqueléticas y b) funciones reguladoras. El hueso está formado por una matriz proteica que se mineraliza de forma mayoritaria con calcio (el más abundante), fosfato y magnesio; para ello es imprescindible un correcto aporte dietético de Ca, fósforo y vitamina D. El Ca iónico (Ca2+) es un componente celular imprescindible para mantener y/o realizar las diferentes funciones especializadas de prácticamente todas las células del organismo. Debido a sus importantes funciones, el Ca2+ debe estar estrechamente regulado, manteniéndose sus concentraciones plasmáticas dentro de unos rangos estrechos. Para ello existe una respuesta precisa frente a la hipocalcemia o la hipercalcemia, en la que intervienen la parathormona, el calcitriol, la calcitonina y la vitamina K. Las ingestas de Ca en la población española son bajas en un porcentaje significativo de la población, especialmente en adultos mayores, sobre todo en las mujeres. La principal fuente de Ca en la dieta son la leche y todos sus derivados. Las verduras de hoja verde, frutas y legumbres pueden tener importancia como fuentes de Ca en un patrón alimentario mediterráneo. La biodisponibilidad del Ca de la dieta depende de factores fisiológicos y dietéticos. Los fisiológicos incluyen la edad, situación fisiológica (gestación y lactación), el estatus de Ca y vitamina D y la enfermedad. Diversos estudios relacionan la ingesta de Ca en la dieta y distintas enfermedades, como osteoporosis, cáncer, enfermedades cardiovasculares y obesidad. PMID:27571860

  10. Estimation of the depth to the fresh-water/salt-water interface from vertical head gradients in wells in coastal and island aquifers

    NASA Astrophysics Data System (ADS)

    Izuka, Scot K.; Gingerich, Stephen B.

    gradients verticaux de charge à partir des mesures de niveau piézométrique faites en cours de foration d'un puits incomplet; le gradient est alors utilisé pour estimer la profondeur de l'interface. L'application de cette méthode à un système eau douce - eau salée simulé numériquement montre que la méthode est la plus précise lorsque le gradient est mesuré dans un puits pénétrant profondément dans l'aquifère. Même en utilisant un puits peu profond, la méthode estime la position de l'interface avec plus de précision que ne le fait la relation de Ghyben-Herzberg lorsqu'il existe un gradient vertical de charge bien marqué. L'application de la méthode à des données de terrain montre que la foration, les méthodes de mesure de niveau et les hétérogénéités au sein de l'aquifère peuvent être la cause de difficultés, mais que les effets de ces difficultés peuvent être réduits. Resumen Para la estimación de la productividad de pozos en acuíferos costeros y en islas es necesaria una estimación precisa de la profundidad de la interfaz teórica entre agua dulce y agua salada. La relación de Ghyben-Herzberg, usada habitualmente para estimar la profundidad de la interfaz, puede subestimar o sobrestimar el espesor de agua dulce, al asumir la ausencia de flujos y gradientes verticales. La estimación de la profundidad de la interfaz debe considerar tanto estos gradientes verticales, como la posible anisotropía del acuífero. En este artículo se presenta un método para calcular los gradientes verticales de niveles a partir de las medidas obtenidas durante la perforación de un pozo parcialmente penetrante para, a partir de este gradiente, estimar la profundidad de la interfaz. La aplicación del método a un sistema de agua dulce/agua salada simulado numéricamente muestra que el método es más preciso cuando el gradiente se mide en un pozo profundo. Incluso en el caso de un pozo superficial, el método permite una estimación más precisa de la

  11. Classificação geométrica de galáxias bianeladas através do metódo CART (Classification And Regression Trees)

    NASA Astrophysics Data System (ADS)

    Ormeño, M. I.; Faúndez-Abans, M.; Cavada, G.

    2003-08-01

    A importância deste trabalho deve-se à seleção de objetos ainda não tratados particularmente como uma família e ao emprego de procedimento estatístico robusto que não precisa de pressupostos ou condições de contorno. Contribui, assim, ao melhor entendimento do cenário das Galáxias Aneladas do diagrama de Hubble via classificação e estudo de subclasses. Selecionaram-se 100 galáxias possuidoras de dois anéis do Catalog of Southern Ringed Galaxies compilado por Ronald Buta, de modo a construir uma amostra completa em termos de conhecimento dos semi-eixos dos anéis interno e externo projetados no plano do céu. Visando uma possível classificação destas galáxias aneladas normais em famílias de acordo com as características geométricas dos anéis, empregou-se primeiramente a Análise de Aglomerados (ferramenta de classificação: medições de semelhança em um espaço bidimensional) para explorar a possível existência de famílias. As variáveis analisadas foram: os diâmetros interiores menores d(I) e maiores D(I), os diâmetros exteriores menores d(E) e maiores D(E), e os ângulos de inclinação dos semi-eixos maiores interiores q(I) e exteriores q(E) dos anéis. Como metodologia de discriminação, empregou-se a construção de Árvores de Classificação. As árvores de classificação constituem um método de discriminação alternativo aos modelos clássicos, tais como a Análise Discriminante e a Regressão Logística, onde uma base de dados é dividida em partições (subgrupos) da árvore por ação de um predictor (variável específica). Os pacotes estatísticos utilizados para o processamento da informação foram: SAS versão 8.0 (Statistical Analisys System) e CART versão 3.6.3. Esta análise estatística sugere a existência de três possíveis famílias de galáxias bianeladas, com base apenas na geometria dos anéis. Como forma exploratória inicial deste resultado, a construção de um diagrama BT (magnitude total) versus o

  12. Elastoplasticidad anisotropa de metales en grandes deformaciones

    NASA Astrophysics Data System (ADS)

    Caminero Torija, Miguel Angel

    El objetivo de este trabajo es el desarrollo de modelos y algoritmos numericos que simulen el comportamiento del material bajo estas condiciones en el contexto de programas de elementos finitos, dando como resultado predicciones mas precisas de los procesos de conformado y deformacion plastica en general. Para lograr este objetivo se han desarrollado diversas tareas destinadas a mejorar las predicciones en tres aspectos fundamentales. El primer aspecto consiste en la mejora de la descripcion del endurecimiento cinematico anisotropo en pequenas deformaciones, lo cual se ha realizado a traves de modelos y algoritmos implicitos de superficies multiples. Ha sido estudiada la consistencia de este tipo de modelos tanto si estan basados en una regla implicita similar a la de Mroz o en la regla de Prager. Ademas se han simulado los ensayos de Lamba y Sidebottom, obteniendo, en contra de la creencia general, muy buenas predicciones con la regla de Prager. Dichos modelos podrian ser extendidos de forma relativamente facil para considerar grandes deformaciones a traves de procedimientos en deformaciones logaritmicas, similares a los desarrollados en esta tesis y detallados a continuacion. El segundo aspecto consiste en la descripcion de la anisotropia elastoplastica inicial. Esto se ha conseguido mediante el desarrollo de modelos y algoritmos para plasticidad anisotropa en grandes deformaciones, bien ignorando la posible anisotropia elastica, bien considerandola simultaneamente con la anisotropia plastica. Para ello ha sido necesario desarrollar primero un nuevo algoritmo de elastoplasticidad anisotropa en pequenas deformaciones consistentemente linealizado y sin despreciar ningun termino, de tal forma que se conserve la convergencia cuadratica de los metodos de Newton. Este algoritmo en pequenas deformaciones ha servido para realizar la correccion plastica de dos algoritmos en grandes deformaciones. El primero de estos algoritmos es una variacion del clasico algoritmo de

  13. Astronomy in the Classroom: Why? (Spanish Title: Astronomía en la Clase: ¿Por Qué?) Astronomia na Sala de Aula: Por Quê?

    NASA Astrophysics Data System (ADS)

    Daros Gama, Leandro; Bagdonas Henrique, Alexandre

    2010-07-01

    particular, é foco deste ensaio: a astronomia. Em que sentido e em que medida valeria a pena abordá-la em aulas, seja de ciências, seja de astronomia especificamente, ou em disciplinas afins? Discutimos neste texto alguns aspectos das vantagens de se tratar essa área do conhecimento nas escolas, levando em conta as dimensões epistemológica e axiológica da astronomia, à luz da visão da ciência como um diálogo inteligente com o mundo, de Bachelard, além da proposta de problematização do conhecimento, de Paulo Freire. Proporemos que de fato a astronomia não precisa ser vista como apenas um novo conjunto de conteúdos a serem ensinados, mas figura como conjunto de temas motivadores para discussões histórico-filosóficas, além de permitir a abordagem de conceitos típicos de outras disciplinas.

  14. Um Projeto de Intervenção nos Espaços de Exposições do Planetário do Parque do Ibirapuera

    NASA Astrophysics Data System (ADS)

    Elias, D. S.; Amaral, L. H.; de Araújo, C. F., Jr.; Matsuura, O. T.; Voelzke, M. R.

    2005-08-01

    Cada vez mais a humanidade, em sua imensa maioria, está alheia às próprias conquistas. A insatisfação com esta realidade tem levado muitos pesquisadores, instituições, empresas e governos a procurar formas alternativas de acompanhar e transmitir todo este acervo científico cultural à sociedade, buscando a melhoria da qualidade da divulgação científica e contribuindo para o processo de cultura e alfabetização científica. Não há tempo nem espaço nos limitados planos curriculares do ensino médio e mesmo nos programas de ensino que propiciem a cultura científica e o acompanhamento do vertiginoso progresso científico e tecnológico atual. Neste sentido, a educação formal escolar precisa ser complementada ou acrescida de uma educação informal, extra-escolar, que possa oferecer à sociedade o que a escola não pode oferecer. A interação do público com museus, feiras de ciências, planetários, exposições científicas e/ou culturais é de grande importância para a aquisição e difusão de conhecimentos relacionados ao mundo científico. Reconhecidamente como um modelo de alfabetização científica esses ambientes promovem uma interação social capaz de propiciar de forma efetiva uma melhor relação ensino-aprendizagem com o público. Partindo desta realidade a Universidade Cruzeiro do Sul e a Escola Municipal de Astronomia (EMA) vêm desenvolvendo um projeto de intervenção no espaço em torno do Planetário do Parque do Ibirapuera com o objetivo de se implantar um ambiente de aprendizagem motivador e desafiador que promova a popularização de conteúdos relacionados à astronomia, astrofísica e cosmologia. Busca-se, também, a aproximação e interação do público com exposições que estão sendo implementadas no planetário. Considerando que se trata de um projeto de mestrado em fase inicial o objetivo do presente trabalho é apresentar a concepção básica e os critérios que estão sendo utilizados do ponto de vista pedag

  15. Climate change impacts on groundwater resources: modelled deficits in a chalky aquifer, Geer basin, Belgium

    NASA Astrophysics Data System (ADS)

    Brouyère, Serge; Carabin, Guy; Dassargues, Alain

    'eau du bassin du Geer en Belgique. Le modèle de nappe est décrit en détail et les résultats sont discutés en terme d'impact du changement climatique sur l'évolution des réserves souterraines. Les premiers résultats indiquent que des déficits d'eau souterraine peuvent apparaître dans le futur en Belgique. Se ha desarrollado un modelo hidrológico integrado (MOHISE) para estudiar el impacto del cambio climático en el ciclo hidrológico de cuencas representativas en Bélgica. Este modelo considera todos los procesos hidrológicos de forma coherente, especialmente en relación con los flujos de aguas subterráneas, que son modelados por medio de un enfoque de elementos finitos espacialmente distribuidos. Gracias a esta herramienta numérica precisa, y tras una calibración y validación detalladas, se puede obtener interpretaciones cuantitativas de los resultados del modelo del acuífero. Considerando escenarios de cambio climático IPCC, se ha aplicado el enfoque integrado a la evaluación del impacto de dicho cambio climático en el ciclo hidrológico de la cuenca del Geer. Se describe los detalles y resultados del modelo de las aguas subterráneas en términos del impacto del cambio climático en la evolución de las reservas de los acuíferos. Los resultados preliminares indican que es posible esperar déficits de aguas subterráneas en un futuro en Bélgica.

  16. Cálculos ab initio con correlación electrónica

    NASA Astrophysics Data System (ADS)

    Merchán Bonete, M.

    Estamos entrando en una era donde la ortogonalidad entre las investigaciones de carácter experimental y de naturaleza teórica se irá difuminando progresivamente y la problemática a resolver quedará en escena como el único actor principal de la obra. Como premisa para una cooperación teórico-experimental de igual a igual, la metodología químico-cuántica utilizada debe ser capaz de ofrecer resultados de carácter predictivo. Sin duda, esta madurez en la metodología químico-cuántica ya la hemos alcanzado hace algunos años, tal y como muestra entre otras muchas, la labor que nuestro grupo ha realizado en el transcurso de la última década, dentro del campo de la Espectroscopía Teórica. Los estudios realizados comprenden una amplia gama de sistemas, variando tanto en tamaño como en complejidad, abordando problemáticas espectroscópicas consideradas tradicionalmente como especialmente controvertidas. Nuestra contribución científica más relevante reside en el carácter cuantitativo de las asignaciones espectroscópicas que hemos propuesto en base a resultados ab initio. Recordemos que en los años noventa los resultados ab initio solían presentar para las energías de excitación de sistemas de tamaño molecular moderado, como el benceno, errores de más de 1 eV. En comparación con el éxito relativo de los métodos semiempíricos, la frustración de la metodología ab initio quedaba todavía más patente. Los estudios que hemos presentado representan una comprensión profunda de los espectros electrónicos en sistemas orgánicos claves, mostrando el camino a seguir para obtener asignaciones espectroscópicas precisas (entre 0.1-0.2 eV). La naturaleza del método CASPT2 junto al diseño de estrategias computacionales nos ha permitido alcanzar el carácter cuantitativo con el que se caracterizan nuestras contribuciones[1,2]. Por todo ello, algunos de los trabajos publicados se consideran clásicos dentro del campo, pues en cierto modo definen el

  17. Elastoplasticidad anisotropa de metales en grandes deformaciones

    NASA Astrophysics Data System (ADS)

    Caminero Torija, Miguel Angel

    El objetivo de este trabajo es el desarrollo de modelos y algoritmos numericos que simulen el comportamiento del material bajo estas condiciones en el contexto de programas de elementos finitos, dando como resultado predicciones mas precisas de los procesos de conformado y deformacion plastica en general. Para lograr este objetivo se han desarrollado diversas tareas destinadas a mejorar las predicciones en tres aspectos fundamentales. El primer aspecto consiste en la mejora de la descripcion del endurecimiento cinematico anisotropo en pequenas deformaciones, lo cual se ha realizado a traves de modelos y algoritmos implicitos de superficies multiples. Ha sido estudiada la consistencia de este tipo de modelos tanto si estan basados en una regla implicita similar a la de Mroz o en la regla de Prager. Ademas se han simulado los ensayos de Lamba y Sidebottom, obteniendo, en contra de la creencia general, muy buenas predicciones con la regla de Prager. Dichos modelos podrian ser extendidos de forma relativamente facil para considerar grandes deformaciones a traves de procedimientos en deformaciones logaritmicas, similares a los desarrollados en esta tesis y detallados a continuacion. El segundo aspecto consiste en la descripcion de la anisotropia elastoplastica inicial. Esto se ha conseguido mediante el desarrollo de modelos y algoritmos para plasticidad anisotropa en grandes deformaciones, bien ignorando la posible anisotropia elastica, bien considerandola simultaneamente con la anisotropia plastica. Para ello ha sido necesario desarrollar primero un nuevo algoritmo de elastoplasticidad anisotropa en pequenas deformaciones consistentemente linealizado y sin despreciar ningun termino, de tal forma que se conserve la convergencia cuadratica de los metodos de Newton. Este algoritmo en pequenas deformaciones ha servido para realizar la correccion plastica de dos algoritmos en grandes deformaciones. El primero de estos algoritmos es una variacion del clasico algoritmo de

  18. Aquifer overexploitation: what does it mean?

    NASA Astrophysics Data System (ADS)

    Custodio, Emilio

    2002-02-01

    ón hidrodinámica precisa. Para adoptar medidas de gestión y de protección se necesita la evaluación cuantitativa de la evolución del acuífero y sus efectos, que se derivan de estudios de detalle en un contexto multidisciplinar y de datos fiables.