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Desenvolvimento ponderal, características da carcaça e eficiência da nutrição energética e protéica no metabolismo ruminal de búfalos e produção de gases in vitro; Growth rate, carcass characteristics and efficiency of nutritional energy and protein metabolism in rumen of buffalo and gas production in vitro

Alves, Teresa Cristina
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 01/07/2010 Português
Relevância na Pesquisa
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Com o objetivo de estudar a espécie bubalina quanto ao desempenho de machos bubalinos do nascimento ao abate em regime de pastejo e as características de carcaça em dois pesos de abate, assim como o metabolismo ruminal de dietas com diferentes níveis de proteína e energia e a produção de gases in vitro, o presente trabalho apresenta-se avaliações feitas em quatro partes. A parte 1 foi realizada com búfalos em crescimento criados à pasto, do nascimento até atingirem dois pesos distintos de abate (517 e 568 kg). Avaliações do desempenho foram realizadas com medição do peso vivo, perímetro torácico, altura de cernelha e comprimento corporal e as avaliações das características da carcaça e carne com determinação do rendimento de carcaça quente e fria, perda no resfriamento, peso da gordura, peso do fígado, temperatura e pH da carcaça, área de olho de lombo, espessura de gordura subcutânea, marmorização, maciez e coloração. A segunda parte avaliou dietas com três níveis de proteína (9%, 12% e 15%) no metabolismo ruminal. Os Itens analisados foram: consumo de nutrientes, pH, amônia e ácidos graxos voláteis no rúmen e degradabilidade in situ. Na parte 3, foram avaliadas dietas com dois níveis de proteína (9 e 15%) e dois de energia (65 e 69% NDT) no metabolismo ruminal. Além dos Itens avaliados na parte 2 foram ainda analisados a digestibilidade com uso de marcador...

Limites críticos topográficos de feições erosivas lineares em Piratininga (SP); Topographical threshold of gully erosions in Piratininga (SP)

Stabile, Rodrigo Augusto
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 30/01/2013 Português
Relevância na Pesquisa
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Considerando a importância de se definir as condições críticas para a deflagração, desenvolvimento e estabilização das voçorocas e outras feições erosivas lineares, e tendo em conta as poucas abordagens nesse sentido realizadas no Brasil, o objetivo geral desta pesquisa é avaliar os limites críticos topográficos para o desenvolvimento das formas resultantes da erosão linear em Piratininga (SP). Os procedimentos metodológicos envolveram a identificação e caracterização das feições erosivas por meio de fotografias aéreas e in situ; a mensuração da declividade (S) em campo e com diversas resoluções de Modelo Digital de Terreno (MDT) e da Área de Contribuição (A) também a partir do MDT; e, a definição dos limites críticos topográficos na forma da seguinte Função Potência: S = a × . A linha do limite crítico foi ajustada no limite inferior dos dados, paralelamente à inclinação linha ortogonal de regressão de S e A. As feições erosivas foram categorizadas em 4 classes e 13 subclasses de acordo com seus aspectos morfométricos e indicadores dos processos atuantes. A mensuração de S e A por diferentes métodos resultou em algumas variações significativas nos dados gerados, sobretudo na comparação entre os valores obtidos em campo e pelo MDT. Foi obtido o seguinte limite crítico topográfico: S = 0...

Correções na determinção do nivel de potencia sonora obtido atraves da tecnica da intensimetria; Corrections in the determination of the sound power level obtained through intensimetry technique

Luiz Antonio Perrone Ferreira de Brito
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 02/07/2006 Português
Relevância na Pesquisa
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Várias cidades brasileiras estão enfrentando problemas de poluição sonora. O ruído de tráfego é a principal causa de incômodo seguido pelo ruído gerado pelos equipamentos utilizados na construção civil. É imperativo que sejam criados parâmetros para controlar a emissão e propagação do ruído gerado pela construção civil para manter uma certa qualidade de vida nas grandes cidades. O nível de potência sonora é um importante parâmetro para análise da propagação sonora no meio ambiente. Pode-se determinar o nível de potência sonora através da medição de intensidade sonora, ín sítu, mesmo na presença de outras fontes de ruído. Assim não é necessária a remoção do equipamento analisado para câmaras anecóicas ou reverberantes. Este trabalho estuda as correções na determinação do nível de potência sonora obtido através da técnica da intensimetria. Deve-se destacar a compilação do estado da arte sobre o assunto. Foram selecionados uma norma e um sistema de medição que possam ser utilizados nos canteiros de obras e indústrias ligadas a construção civil. Os resultados das medições do nível de potência sonora de uma furadeira elétrica, com e sem ruído de fundo, obtidos através da norma ISO 9614-2 (1995) foram comparados aos obtidos em uma camara reverberante através da norma ISO 3741 (1999). Esta comparação permitiu o estudo de três novos indices de campo...

Características biométricas testiculares em carneiros Santa Inês submetidos a diferentes regimes de suplementação protéica e tratamentos anti-helmínticos; Testicular biometric characteristics in Santa Inês sheep submitted to protein supplementation

Louvandini, Helder; Pimentel, Concepta Margaret McManus; Martins, Rodrigo Duarte; Lucci, Carolina Madeira; Corrêa, Patrícia Spoto
Fonte: Universidade de Brasília Publicador: Universidade de Brasília
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
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Para avaliar as características biométricas testiculares de carneiros da raça Santa Inês, 24 cordeiros machos, inteiros, com peso médio inicial de 24,5 kg ± 2,88, aos quatro meses de idade, foram distribuídos em quatro tratamentos: APv (animais vermifugados + concentrado com alta proteína), APn (animais não-vermifugados + concentrado com alta proteína), BPv (animais vermifugados + concentrado com baixa proteína), BPn (animais não vermifugados + concentrado com baixa proteína) durante 8 meses e meio. Antes do abate, realizaram-se as medições testiculares in situ: perímetro escrotal (PE), comprimento (COMP), largura testicular (LARG) e a forma dos testículos, bem como o volume testicular (cilindro e prolato esferóide). Após o abate, determinaram- se o volume testicular real (VOLR), o comprimento (COMPV) e a largura testicular (LARGV). Observou-se que os testículos dos animais eram simétricos e que o uso do paquímetro é uma forma altamente confiável para se realizar as medições testiculares in situ. O formato dos testículos afetou diretamente seu volume. O valor médio das equações do prolato esferóide e cilíndrica é a forma mais acurada para se estimar o volume testicular real em ovinos Santa Inês. O alto teor de proteína da dieta e o tratamento antiparasitário possibilitaram uma melhoria do peso corporal dos ovinos...

In situ pulse respirometric methods for the estimation of kinetic and stoichiometric parameters in aerobic microbial communities

Oliveira, Catarina S.; Ordaz, Alberto; Ferreira, E. C.; Alves, M. M.; Thalasso, Frédéric
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em //2011 Português
Relevância na Pesquisa
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In situ pulse respirometry was applied in an activated sludge bubble column treating synthetic wastewater for the estimation of the (i) maximum specific oxygen consumption rate, (ii) substrate affinity constant, (iii) biomass growth yield, (iv) maintenance coefficient, and (v) specific endogenous respiration rate. Parameters obtained through respirometry were compared to those obtained by the chemostat method, based on substrate and biomass measurements, under several dilution rates. The low sensitivity of substrate measurement methods and the difficulties of sampling heterogeneous biomass suspension are critical issues limiting the applicability of the chemostat method. Additionally, the extensive time consuming nature of this method allows concluding that chemostat method presents several disadvantages in comparison with in situ pulse respirometric techniques. Parameters were obtained from respirograms by fitting ASM1 and ASM3 models, and from experiments performed by injecting pulses of increasing substrate concentration. The injection of pulses of increasing concentration was the most adequate method, with several advantages such as a simpler experimental data interpretation and results with better confidence. Considering the assessment and comparison of the experimental and calculation methods presented...

Shape determinations of ribosomal proteins in situ.

Nierhaus, K H; Lietzke, R; May, R P; Nowotny, V; Schulze, H; Simpson, K; Wurmbach, P; Stuhrmann, H B
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /05/1983 Português
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45.61%
Ribosomes are heterogeneous for neutrons because RNA and proteins have different neutron-scattering-length densities. This heterogeneity is an obstacle to the shape determination of single ribosomal components within the ribosome. Therefore, we homogenized (matched) the neutron-scattering-length densities of RNA and proteins. 23S and 5S RNA from the large ribosomal subunit were isolated from cells grown in a medium containing 76% 2H2O. The total protein fraction of the large ribosomal subunit was isolated from cells grown in a medium containing 84% 2H2O. When these constituents were used for total reconstitution of 50S subunits, neutron scattering measurements of the reconstituted particles revealed excellent matching near 100% 2H2O. A three-step reconstitution procedure was developed that allowed the reconstitution of 50S subunits from deuterated RNA, deuterated total (i.e., unfractionated) proteins, and single protonated proteins. The reconstituted particles contain one protonated protein or two in a matched ribosomal matrix and were used for shape determination or distance measurement of mass centers of gravity, respectively. The signal/noise ratio is high enough to allow measurement in solutions containing nearly 100% 2H2O at concentrations of only 300-500 A260 nm units/ml. Our experiments have proved the feasibility of our biochemical strategy. The shape determinations of ribosomal proteins in situ gave radii of gyration for L1...

Direct Measurement of Turgor and Osmotic Potential in Individual Epidermal Cells 1: Independent Confirmation of Leaf Water Potential as Determined by in Situ Psychrometry

Shackel, Kenneth A.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /04/1987 Português
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The pressure probe, which is routinely used to measure the turgor potential (Ψp) of individual epidermal cells in Tradescantia virginiana (L.), has also been used to sample small volumes of vacuolar fluid from these same cells (as low as 0.02 nl) for measurement of cellular solute (osmotic) potential (Ψs) in a micro freezing point osmometer. The water potential components Ψp and Ψo have been used to calculate the total water potential of individual epidermal cells (Ψcell) which has then been directly compared to the total leaf water potential (Ψleaf) measured psychrometrically. The relation of Ψleaf and Ψcell to leaf transpiration indicates that in T. virginiana, a relatively straightforward relation exists between the level of water flow through the leaf tissue, and the ΔΨ within the leaf, between two points along the water flow pathway. Substantial agreement was found between the two independent, in situ methods of measuring Ψ when extrapolated to zero transpiration conditions. These results are discussed with respect to the thermodynamics of water transport in plant tissues.

Characterization of a rapid cellular-fractionation technique for hepatocytes. Application in the measurement of mitochondrial membrane potential in situ.

Shears, S B; Kirk, C J
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 15/04/1984 Português
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A rapid cellular-fractionation technique [ Hoek , Nicholls & Williamson (1980) J. Biol. Chem. 255, 1458-1464] was further characterized by using hepatocytes. Of the mitochondrial marker-enzyme activity, 80% was routinely separated from 71-98% of the total cell activities of marker enzymes for plasma membranes, Golgi-membranes, endoplasmic reticulum, lysosomes and cytosol. The mitochondria were contaminated with 53% of cell nuclei. [3H]Triphenylmethylphosphonium ion (TPMP+) was added to hepatocytes in an attempt to measure cellular transmembrane electrical potentials. After rapid cell fractionation the electrical potential between mitochondria in situ and the incubation medium was found to be 202 mV. This value was slightly increased when hepatocytes were treated with oligomycin, but substantially decreased by oligomycin plus an uncoupler of oxidative phosphorylation. Although estimates of TPMP+ binding were obtained, substantial difficulties prevented the accurate measurement of the electrical potential across the plasma membrane. It is concluded that TPMP+ may be employed to demonstrate the integrity of mitochondria during the fractionation procedures. However, the cation is inadequate for the determination of the separate components of the electrical potential between the mitochondrial matrix and the incubation medium.

A new principle for rapid immunoassay of proteins based on in situ precipitate-enhanced ellipsometry.

Robers, M; Rensink, I J; Hack, C E; Aarden, L A; Reutelingsperger, C P; Glatz, J F; Hermens, W T
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /05/1999 Português
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45.61%
A new technique is presented that allows measurement of protein concentrations in the picomolar range with an assay time of only 10-20 min. The method is an enzyme-linked immunosorbent assay (ELISA), but uses in-situ ellipsometric measurement of a precipitating enzyme product instead of the usual colorimetric detection of accumulating enzyme product in solution. Quantitative validation was obtained by use of annexin V, a protein with high binding affinity for phosphatidylserine-containing phospholipid membranes, resulting in a transport-limited adsorption rate. This property was exploited to obtain a range of low surface concentrations of annexin V by timed exposures of phospholipid bilayers to known concentrations of annexin V. Using polyvinylchloride (PVC)-coated and silanized silicon slides, various versions of this technique were used for the rapid assay of fatty acid-binding protein (FABP), a recently introduced early marker for acute myocardial infarction with a normal plasma concentration below 1 nmol/l, interleukin 6 (IL-6), a cytokine with normal plasma concentrations below 1 pmol/l, and again, annexin V. A possible future application of the method in the development of a one-step ELISA is discussed.

Platform for in situ real-time measurement of protein-induced conformational changes of DNA

Spuhler, Philipp S.; Knežević, Jelena; Yalçin, Ayça; Bao, Qiuye; Pringsheim, Erika; Dröge, Peter; Rant, Ulrich; Ünlü, M. Selim
Fonte: National Academy of Sciences Publicador: National Academy of Sciences
Tipo: Artigo de Revista Científica
Português
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45.61%
A platform for in situ and real-time measurement of protein-induced conformational changes in dsDNA is presented. We combine electrical orientation of surface-bound dsDNA probes with an optical technique to measure the kinetics of DNA conformational changes. The sequence-specific Escherichia coli integration host factor is utilized to demonstrate protein-induced bending upon binding of integration host factor to dsDNA probes. The effects of probe surface density on binding/bending kinetics are investigated. The platform can accommodate individual spots of microarrayed dsDNA on individually controlled, lithographically designed electrodes, making it amenable for use as a high throughput assay.

In Situ Roughness Measurements for the Solar Cell Industry Using an Atomic Force Microscope

González-Jorge, Higinio; Alvarez-Valado, Victor; Valencia, Jose Luis; Torres, Soledad
Fonte: Molecular Diversity Preservation International (MDPI) Publicador: Molecular Diversity Preservation International (MDPI)
Tipo: Artigo de Revista Científica
Publicado em 20/04/2010 Português
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45.61%
Areal roughness parameters always need to be under control in the thin film solar cell industry because of their close relationship with the electrical efficiency of the cells. In this work, these parameters are evaluated for measurements carried out in a typical fabrication area for this industry. Measurements are made using a portable atomic force microscope on the CNC diamond cutting machine where an initial sample of transparent conductive oxide is cut into four pieces. The method is validated by making a comparison between the parameters obtained in this process and in the laboratory under optimal conditions. Areal roughness parameters and Fourier Spectral Analysis of the data show good compatibility and open the possibility to use this type of measurement instrument to perform in situ quality control. This procedure gives a sample for evaluation without destroying any of the transparent conductive oxide; in this way 100% of the production can be tested, so improving the measurement time and rate of production.

Analysis of MicroRNA Niches: Techniques to Measure Extracellular MicroRNA and Intracellular MicroRNA In Situ

Parikh, Victoria N.; Chan, Stephen Y.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em //2013 Português
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MicroRNA (miRNA) are small, non-coding RNA molecules that negatively regulate gene expression and control a wide range of cellular processes. Extracellular forms of miRNA circulating in the bloodstream (circulating miRNA, c-miRNA) are of increasing interest for their potential as biomarkers and long-range physiological signaling molecules. Precise measurement of intracellular miRNA expression is possible but can be challenging, especially in the context of specialized tissue niches in vivo. The accurate measurement of extracellular miRNA presents other obstacles stemming from their low concentrations and confounding sources of intracellular miRNA that contaminate RNA extraction protocols. Here, we describe multiple methods to isolate extracellular miRNA from cell culture media, serum, and plasma in order to accurately measure their variable expression under different conditions. We additionally describe an in situ staining protocol designed not only to quantify, but also to localize miRNA in formalin-fixed paraffin-embedded (FFPE) tissue, that may prove useful in describing the action of c-miRNA before they leave their tissue of origin and after they potentially arrive at their target destination.

Tensile Strain Measurement Using Mechanical and in Situ Optical Techniques in Bi-metallic Ni-base Superalloys

ABBADI Mohammed; DE HAAN FREDERICUS; HAEHNER PETER
Fonte: ELSEVIER SCI LTD Publicador: ELSEVIER SCI LTD
Tipo: Articles in Journals Formato: Printed
Português
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The mechanical performance in terms of tensile properties of a nickel-base superalloy bi-material was investigated, to study the tensile strength of the joint. The results of strain measurement and control by means of usual clip-on extensometry, which gives the overall strain, cannot reveal the local deformation. To have more detail about the local strain fields, particularly in the vicinity of the interface which remains the most brittle part of the bi-metal, an in situ image capture and processing technique adapted from particle image velocimetry was used. The two techniques showed a perfect correlation with the peculiarity of a precise assessment of the local strain in the case of the optical method. Tensile curves obtained at constant strain rate showed serrated yielding associated with inhomogeneous plastic flow at high temperatures. This instability of strain rate softening type (strain localization) was well detected by means of the optical technique.; JRC.F.3-High Flux and Future Reactors

Top Quark Mass Measurement in the lepton+jets Channel Using a Matrix Element Method and in situ Jet Energy Calibration

Aaltonen, Terhi; Álvarez González, Bárbara; Amerio, Silvia; Amidei, Dante; Anastassov, Anton; Annovi, Alberto; Antos, Jaroslav; Apollinari, Giorgio; Appel, Jeffrey A.; Apresyan, Artur; Casal Laraña, Bruno; Cuevas Maestro, Francisco Javier; Gómez Gram
Fonte: American Physical Society Publicador: American Physical Society
Tipo: info:eu-repo/semantics/article; publishedVersion
Português
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A precision measurement of the top quark mass mt is obtained using a sample of tt̅ events from pp̅ collisions at the Fermilab Tevatron with the CDF II detector. Selected events require an electron or muon, large missing transverse energy, and exactly four high-energy jets, at least one of which is tagged as coming from a b quark. A likelihood is calculated using a matrix element method with quasi-Monte Carlo integration taking into account finite detector resolution and jet mass effects. The event likelihood is a function of mt and a parameter ΔJES used to calibrate the jet energy scale in situ. Using a total of 1087 events in 5.6  fb-1 of integrated luminosity, a value of mt=173.0±1.2  GeV/c2 is measured.

Dislocation Loop Formation and Growth under In Situ Laser and/or Electron Irradiation

Yang, Zhanbing; Sakaguchi, Norihito; Watanabe, Seiichi; Kawai, Masayoshi
Fonte: Nature Publishing Group Publicador: Nature Publishing Group
Tipo: Artigo de Revista Científica
Publicado em 12/12/2011 Português
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Vacancies and interstitial atoms are primary lattice (point) defects that cause observable microstructural changes, such as the formation of dislocation loops and voids in crystalline solids. These defects' diffusion properties determine the phase stability and environmental resistibility of macroscopic materials under ambient conditions. Although in situ methods have been proposed for measuring the diffusion energy of point defects, direct measurement has been limited. In this study, we propose an alternative in situ method to measure the activation energy for vacancy migration under laser irradiation using a pulsed laser beam from a laser-equipped high-voltage electron microscope (laser-HVEM). We made in situ observations that revealed the formation and growth of vacancy dislocation loops in an austenitic stainless steel during laser irradiation. These loops continued to grow when thermal annealing was performed after laser irradiation at the same temperature. We anticipate that laser-HVEM will provide a new method for investigating lattice defects.

Self-heterodyne detection of the {\it in-situ} phase of an atomic-SQUID

Mathew, Ranchu; Kumar, Avinash; Eckel, Stephen; Jendrzejewski, Fred; Campbell, Gretchen K.; Edwards, Mark; Tiesinga, Eite
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
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We present theoretical and experimental analysis of an interferometric measurement of the {\it in-situ} phase drop across and current flow through a rotating barrier in a toroidal Bose-Einstein condensate (BEC). This experiment is the atomic analog of the rf-superconducting quantum interference device (SQUID). The phase drop is extracted from a spiral-shaped density profile created by the spatial interference of the expanding toroidal BEC and a reference BEC after release from all trapping potentials. We characterize the interferometer when it contains a single particle, which is initially in a coherent superposition of a torus and reference state, as well as when it contains a many-body state in the mean-field approximation. The single-particle picture is sufficient to explain the origin of the spirals, to relate the phase-drop across the barrier to the geometry of a spiral, and to bound the expansion times for which the {\it in-situ} phase can be accurately determined. Mean-field estimates and numerical simulations show that the inter-atomic interactions shorten the expansion time scales compared to the single-particle case. Finally, we compare the mean-field simulations with our experimental data and confirm that the interferometer indeed accurately measures the {\it in-situ} phase drop.; Comment: 8 pages...

Top-Quark Mass Measurement in the Dilepton Channel Using {\it in situ} Jet Energy Scale Calibration

Lee, Hyun Su
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 03/08/2012 Português
Relevância na Pesquisa
45.61%
We employ a top-quark mass measurement technique in the dilepton channel with {\it in situ} jet energy scale calibration. Three variables having different jet energy scale dependences are used simultaneously to extract not only the top-quark mass but also the energy scale of the jet from a single likelihood fit. Monte Carlo studies with events corresponding to an integrated luminosity of 5 fb$^{-1}$ proton-proton collisions at the Large Hadron Collider $\sqrt{s} = 7$ TeV are performed. Our analysis suggests that the overall jet energy scale uncertainty can be significantly reduced and the top-quark mass can be determined with a precision of less than 1 GeV/c$^2$, including jet energy scale uncertainty, at the Large Hadron Collider.; Comment: Submitted to Phys. Rev. D

In-Situ Measurements of the Secondary Electron Yield in an Accelerator Environment: Instrumentation and Methods

Hartung, W. H.; Asner, D. M.; Conway, J. V.; Dennett, C. A.; Greenwald, S.; Kim, J. -S.; Li, Y.; Moore, T. P.; Omanovic, V.; Palmer, M. A.; Strohman, C. R.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 10/12/2014 Português
Relevância na Pesquisa
45.61%
The performance of a particle accelerator can be limited by the build-up of an electron cloud (EC) in the vacuum chamber. Secondary electron emission from the chamber walls can contribute to EC growth. An apparatus for in-situ measurements of the secondary electron yield (SEY) in the Cornell Electron Storage Ring (CESR) was developed in connection with EC studies for the CESR Test Accelerator program. The CESR in-situ system, in operation since 2010, allows for SEY measurements as a function of incident electron energy and angle on samples that are exposed to the accelerator environment, typically 5.3 GeV counter-rotating beams of electrons and positrons. The system was designed for periodic measurements to observe beam conditioning of the SEY with discrimination between exposure to direct photons from synchrotron radiation versus scattered photons and cloud electrons. The samples can be exchanged without venting the CESR vacuum chamber. Measurements have been done on metal surfaces and EC-mitigation coatings. The in-situ SEY apparatus and improvements to the measurement tools and techniques are described.; Comment: 16 pages, 18 figures; this paper is a condensed version of arXiv:1407.0772

Top Quark Mass Measurement in the Lepton + Jets Channel Using a Matrix Element Method and in situ Jet Energy Calibration

al., T. Aaltonen et
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
45.61%
A precision measurement of the top quark mass m_t is obtained using a sample of ttbar events from ppbar collisions at the Fermilab Tevatron with the CDF II detector. Selected events require an electron or muon, large missing transverse energy, and exactly four high-energy jets, at least one of which is tagged as coming from a b quark. A likelihood is calculated using a matrix element method with quasi-Monte Carlo integration taking into account finite detector resolution and jet mass effects. The event likelihood is a function of m_t and a parameter DJES to calibrate the jet energy scale /in situ/. Using a total of 1087 events, a value of m_t = 173.0 +/- 1.2 GeV/c^2 is measured.; Comment: 7 pages, 3 figures. Edited in response to referee comments and resubmitted to Phys. Rev. Lett

Quantitatively Measuring In situ Flows using a Self-Contained Underwater Velocimetry Apparatus (SCUVA)

Katija, Kakani; Colin, Sean P.; Costello, John H.; Dabiri, John O.
Fonte: JoVE Publicador: JoVE
Tipo: Article; PeerReviewed Formato: application/pdf; video/quicktime
Publicado em 31/10/2011 Português
Relevância na Pesquisa
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The ability to directly measure velocity fields in a fluid environment is necessary to provide empirical data for studies in fields as diverse as oceanography, ecology, biology, and fluid mechanics. Field measurements introduce practical challenges such as environmental conditions, animal availability, and the need for field-compatible measurement techniques. To avoid these challenges, scientists typically use controlled laboratory environments to study animal-fluid interactions. However, it is reasonable to question whether one can extrapolate natural behavior (i.e., that which occurs in the field) from laboratory measurements. Therefore, in situ quantitative flow measurements are needed to accurately describe animal swimming in their natural environment. We designed a self-contained, portable device that operates independent of any connection to the surface, and can provide quantitative measurements of the flow field surrounding an animal. This apparatus, a self-contained underwater velocimetry apparatus (SCUVA), can be operated by a single scuba diver in depths up to 40 m. Due to the added complexity inherent of field conditions, additional considerations and preparation are required when compared to laboratory measurements. These considerations include...