6,549 research outputs found

    Sealing Capability and SEM Observation of the Implant-Abutment Interface

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    To evaluate the sealing capability of external hexagon implant systems and assess the marginal fit, two groups (n = 10 each) were employed: SIN (Sistema de Implantes Nacional, Brazil) and Osseotite, (Biomet 3i, USA). Sealing capability was determined by placing 0.7 μL of 1% acid-red solution in the implant wells before the torque of their respective abutments. Specimens were then placed into 2.5 mL vials filled with 1.3 mL of distilled water with the implant-abutment interface submerged. Three samples of 100 μL water were collected at previously determinate times. The absorbance was measured with a spectrophotometer, and the data were analyzed by Two-way ANOVA (P < .05) and Tukey's test. Marginal fit was determined using SEM. Leakage was observed for both groups at all times and was significantly higher at 144 hrs. SEM analysis depicted gaps in the implant-abutment interface of both groups. Gaps in the implant-abutment interface were observed along with leakage increased at the 144 hrs evaluation period

    Por uma nova cultura da água no ensino básico

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    A presente comunicação centra-se na apresentação à comunidade científica de um Projecto de investigação em Educação que tem como finalidade produzir contributos para o Ensino Básico, no âmbito do que se designa como uma Nova Cultura da Água. Com esta iniciativa pretendemos não só alertar para a pertinência e importância de estudos em ordem a uma temática cada vez mais emergente, mas também recolher contributos significativos de uma comunidade mais alargada. O referido projecto centra-se pois no bem Água. Começará por procurar conhecer melhor como ele é evocado e tratado no Ensino Básico. Destina-se a aprofundar e promover teorias, conhecimentos, competências, valores, atitudes e práticas que potenciem o bom uso e a protecção daquele bem, e de um modo mais geral uma alteração de posturas culturais e mesmo civilizacionais. Fá-lo-á segundo perspectivas científicas, pedagógicas, didácticas e sociais em parte já construídas e em parte a construir, e que justificadamente se considerem adequadas. O Projecto assume estar à partida marcado por saberes, perspectivas, ideais, dilemas e objectivos dos elementos da equipa do Projecto e por outras visões que, globalmente e de um modo aproximativo, aglomeramos sob a designação Nova Cultura da Água. Simultaneamente, assume que pretende contribuir para que tal Nova Cultura da Água seja mais bem compreendida e especificada, e em particular para que ela seja mais enriquecida com contributos portugueses. O âmbito central de intervenção do Projecto é o Ensino Básico, mas desde logo isso implica a sua intersecção com a Formação (Inicial e Contínua) de Professores, e portanto com o Ensino Superior. Além disso, pela natureza do tema, do bem, em estudo, o Projecto intersecta-se também com os mundos das Ciências e das Tecnologias. Intersecta-se também com a Sociedade em geral, e designadamente com a formação para a cidadania de cidadão portugueses que são também cidadãos da Península Ibérica, da Europa e do Mundo. O Projecto terá pois múltiplas incidências e mesmo, previsivelmente, contributos de vários tipos e âmbitos, designadamente a nível de divulgação científica e a um nível pedagógico geral. Mas é essencialmente um Projecto do âmbito da Didáctica. Tem a sua focagem na Escola, portanto em ambientes de ensino e aprendizagem formais, e incide sobre meios e métodos relacionados com ambientes de aula (em sentido lato)

    Método para determinação de umidade de plantas aromáticas.

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    Materias necessários; Reagentes; Equipamentos e vidrarias; Protocolo do método de determinação de umidade; Destilação da amostra; Obtenção do destilado; Determinação do teor de umidade.bitstream/CNPAT-2010/11962/1/cotb-136.pd

    ITC's strategic plan for Open Science 2021-2025:towards an open future

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    Open Science (OS) is an umbrella term comprising principles to increase the transparency of research. Besides Open Access to scientific articles, these principles contain public availability of reusable methods (e.g., code and tools), data, and educational materials. This document outlines a plan to achieve the transition towards OS. ITC’s Strategic Plan for OS 2021-2025 - Towards an Open Future contains five initiatives: 1.OS at ITC aims to provide guidelines and OS capacity development to address the obstacles ITC researchers encounter when doing OS. 2.The ITC Knowledge Hub will provide services and tools to access, create, and publish open research, including scientific results based on qualitative/quantitative analyses using computational workflows. 3.Open Educational Resources will be addressed by exploring options to realise Open Educational Resources at ITC and providing lecturers with guidelines and support to create them. 4.The OS Community Twente serves as an inter-disciplinary, bottom-up community to promote, learn, share, and discuss OS practices. 5.Research & Funding aims to address challenges in OS through innovative developments and user studies. A further output is to generate funding to realise the ambitious aims presented in the plan. For a successful OS transition, the initiatives aim to address the Rewards & Recognition system, valorise Sharing & Collaboration, develop OS Knowledge & Skills, and foster Cultural change & Societal impact

    New Results from the Cryogenic Dark Matter Search Experiment

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    Using improved Ge and Si detectors, better neutron shielding, and increased counting time, the Cryogenic Dark Matter Search (CDMS) experiment has obtained stricter limits on the cross section of weakly interacting massive particles (WIMPs) elastically scattering from nuclei. Increased discrimination against electromagnetic backgrounds and reduction of neutron flux confirm WIMP-candidate events previously detected by CDMS were consistent with neutrons and give limits on spin-independent WIMP interactions which are >2X lower than previous CDMS results for high WIMP mass, and which exclude new parameter space for WIMPs with mass between 8-20 GeV/c^2.Comment: 4 pages, 4 figure

    Exclusion limits on the WIMP-nucleon cross-section from the Cryogenic Dark Matter Search

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    The Cryogenic Dark Matter Search (CDMS) employs low-temperature Ge and Si detectors to search for Weakly Interacting Massive Particles (WIMPs) via their elastic-scattering interactions with nuclei while discriminating against interactions of background particles. For recoil energies above 10 keV, events due to background photons are rejected with >99.9% efficiency, and surface events are rejected with >95% efficiency. The estimate of the background due to neutrons is based primarily on the observation of multiple-scatter events that should all be neutrons. Data selection is determined primarily by examining calibration data and vetoed events. Resulting efficiencies should be accurate to about 10%. Results of CDMS data from 1998 and 1999 with a relaxed fiducial-volume cut (resulting in 15.8 kg-days exposure on Ge) are consistent with an earlier analysis with a more restrictive fiducial-volume cut. Twenty-three WIMP candidate events are observed, but these events are consistent with a background from neutrons in all ways tested. Resulting limits on the spin-independent WIMP-nucleon elastic-scattering cross-section exclude unexplored parameter space for WIMPs with masses between 10-70 GeV c^{-2}. These limits border, but do not exclude, parameter space allowed by supersymmetry models and accelerator constraints. Results are compatible with some regions reported as allowed at 3-sigma by the annual-modulation measurement of the DAMA collaboration. However, under the assumptions of standard WIMP interactions and a standard halo, the results are incompatible with the DAMA most likely value at >99.9% CL, and are incompatible with the model-independent annual-modulation signal of DAMA at 99.99% CL in the asymptotic limit.Comment: 40 pages, 49 figures (4 in color), submitted to Phys. Rev. D; v.2:clarified conclusions, added content and references based on referee's and readers' comments; v.3: clarified introductory sections, added figure based on referee's comment

    Radiogenic and Muon-Induced Backgrounds in the LUX Dark Matter Detector

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    The Large Underground Xenon (LUX) dark matter experiment aims to detect rare low-energy interactions from Weakly Interacting Massive Particles (WIMPs). The radiogenic backgrounds in the LUX detector have been measured and compared with Monte Carlo simulation. Measurements of LUX high-energy data have provided direct constraints on all background sources contributing to the background model. The expected background rate from the background model for the 85.3 day WIMP search run is (2.6±0.2stat±0.4sys)×103(2.6\pm0.2_{\textrm{stat}}\pm0.4_{\textrm{sys}})\times10^{-3}~events~keVee1_{ee}^{-1}~kg1^{-1}~day1^{-1} in a 118~kg fiducial volume. The observed background rate is (3.6±0.4stat)×103(3.6\pm0.4_{\textrm{stat}})\times10^{-3}~events~keVee1_{ee}^{-1}~kg1^{-1}~day1^{-1}, consistent with model projections. The expectation for the radiogenic background in a subsequent one-year run is presented.Comment: 18 pages, 12 figures / 17 images, submitted to Astropart. Phy

    Search for inelastic dark matter with the CDMS II experiment

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    Results are presented from a reanalysis of the entire five-tower data set acquired with the Cryogenic Dark Matter Search (CDMS II) experiment at the Soudan Underground Laboratory, with an exposure of 969 kg-days. The analysis window was extended to a recoil energy of 150 keV, and an improved surface-event background-rejection cut was defined to increase the sensitivity of the experiment to the inelastic dark matter (iDM) model. Three dark matter candidates were found between 25 keV and 150 keV. The probability to observe three or more background events in this energy range is 11%. Because of the occurrence of these events the constraints on the iDM parameter space are slightly less stringent than those from our previous analysis, which used an energy window of 10-100 keV.Comment: 10 pages, 10 figures, minor changes to match published version, conclusion unchange
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