840 research outputs found
Refractive index inhomogeneity within an aerogel block
Evaluating local inhomogeneities of the refractive index inside aerogel blocks to be used as Cherenkov radiator is important for a high energy physics experiment where angular resolution is crucial. Two approaches are described and compared. The first one is based on the bending of a laser beam induced by refractive index gradients along directions normal to the unperturbed optical path. The second method exploits the Cherenkov effect itself by shooting an ultra-relativistic collimated electron beam through different points of the aerogel surface. Local refractive index variations result in sizable differences in the Cherenkov photons distribution. © 2005 Elsevier B.V. All rights reserved
Estimating additive and dominance variances for complex traits in pigs combining genomic and pedigree information
Knowledge of dominance effects should improve ge-netic evaluations, provide the accurate selection of purebred animals, and enable better breeding strategies, including the exploitation of het-erosis in crossbreeds. In this study, we combined genomic and pedi-gree data to study the relative importance of additive and dominance genetic variation in growth and carcass traits in an F2 pig population. Two GBLUP models were used, a model without a polygenic effect (ADM) and a model with a polygenic effect (ADMP). Additive effects played a greater role in the control of growth and carcass traits than did dominance effects. However, dominance effects were important for all traits, particularly in backfat thickness. The narrow-sense and broad-sense heritability estimates for growth (0.06 to 0.42, and 0.10 to 0.51, respectively) and carcass traits (0.07 to 0.37, and 0.10 to 0.76, respec-tively) exhibited a wide variation. The inclusion of a polygenic effect in the ADMP model changed the broad-sense heritability estimates only for birth weight and weight at 21 days of age
Brasil y sus intereses en la construcción de Cachuela Esperanza, Bolivia
La necesidad de energía obliga a los países a reflexionar sobre las formas de obtener este recurso más limpio y más barato. Como alternativa a esto se promueven intentos de integración entre los diferentes países. El Complejo Madeira tiene un gran potencial para la producción de energía hidroeléctrica, como resultado de caídas y rápido flujo de agua en los afluentes del río Madeira, en especial el río Beni, donde se planea construir una central hidroeléctrica en Cachuela Esperanza, como resultado de la alianza entre Brasil y Bolivia. El proyecto hidroeléctrico está rodeado por controversias y afecta la imagen de Brasil pues éste puede ser considerado como un país oportunista, ya que la mayoría de los impactos negativos de la construcción no se exportarán, y el país se beneficiará de la venta de energía a bajo costo por Bolivia.The energy requirement obliges countries to think on ways to get this resource cleanly and cheaply. Alternative to this are the attempts of integration between different countries. The Madeira Complex has great potential for hydroelectric generation as a result of falls and rapid flow of water in the tributaries of the Madeira river, especially the Beni river, where building a hydroelectric plant in Cachuela Esperanza is planned, as a result of the partnership between Brazil and Bolivia. The hydroelectric project is surrounded by controversy and affects the image of Brazil as opportunistic, since most of the negative impacts resulting from the construction will not be exported, and the country will benefit from the sale of low-cost energy through Bolivia.A necessidade de energia exige aos países a refletir sobre as formas de obter esse recurso mais limpo e mais barato. Como alternativa a isto se promovem esforços de integração entre os diferentes países. O Complexo Madeira tem um grande potencial para a produção de energia hidroelétrica, como resultado de quedas e rápido fluxo de água nos afluentes do rio Madeira, em especial o Rio Beni, onde se planeja construir uma usina hidrelétrica em Cachuela Esperanza, como resultado da aliança entre Brasil e Bolívia. O projeto da hidrelétrica é cercada de polêmicas e afeta a imagem do Brasil, pois este país pode ser considerado como um país oportunista, já que a maioria dos impactos negativos da construção não será exportada, e o país se beneficiará com a venda de energia a baixo custo por parte de Bolívia
Serotyping and evaluation of the virulence in mice of Streptococcus suis strains isolated from diseased pigs
A total of 110 strains of Streptococcus suis, isolated from diseased pigs in Brazil were serotyped and analyzed for virulence. Serotyping of the strains resulted in the following classification: 42 strains of serotype 2 (38.2%), 10 strains of serotype 14 (9.1%), seven strains of serotype 9 (6.4%), three strains each of serotype 7 and 11 (2.7%), two strains each of serotype 1 and 8 (1.8%) and one strain each of serotypes ½, 3, 5, 6 and 10 (0.9%). Cross reactions among serotypes 1, 14 and 7 were observed in 21 strains (19.1%). Only 41.9% of the strains were lethal for mice using the pathogenicity test.Um total of 110 amostras de Streptococcus suis isoladas de suínos doentes, no Brasil foram sorotipificadas e analisadas para a virulência. Sorotipificação das amostras resultou na seguinte classificação: 42 amostras do sorotipo 2 (38,2%), 10 amostras do sorotipo 14 (9,1%), sete amostras do sorotipo 9 (6,4%), três amostras de cada sorotipo, 7 e 11 (2,7%), duas amostras de cada sorotipo, 1 e 8 (1,8%) e uma amostra de cada um dos sorotipos, ½, 3, 5, 6 e 10 (0,9%). Reações cruzadas entre os sorotipos 1, 14 e 7 foram observadas em 21 amostras (19,1%). Somente 41,9% das amostras foram patogênicas para camundongos
Fragmentation Experiment and Model for Falling Mercury Drops
The experiment consists of counting and measuring the size of the many
fragments observed after the fall of a mercury drop on the floor. The size
distribution follows a power-law for large enough fragments. We address the
question of a possible crossover to a second, different power-law for small
enough fragments. Two series of experiments were performed. The first uses a
traditional film photographic camera, and the picture is later treated on a
computer in order to count the fragments and classify them according to their
sizes. The second uses a modern digital camera. The first approach has the
advantage of a better resolution for small fragment sizes. The second, although
with a poorer size resolution, is more reliable concerning the counting of all
fragments up to its resolution limit. Both together clearly indicate the real
existence of the quoted crossover.
The model treats the system microscopically during the tiny time interval
when the initial drop collides with the floor. The drop is modelled by a
connected cluster of Ising spins pointing up (mercury) surrounded by Ising
spins pointing down (air). The Ising coupling which tends to keep the spins
segregated represents the surface tension. Initially the cluster carries an
extra energy equally shared among all its spins, corresponding to the coherent
kinetic energy due to the fall. Each spin which touches the floor loses its
extra energy transformed into a thermal, incoherent energy represented by a
temperature used then to follow the dynamics through Monte Carlo simulations.
Whenever a small piece becomes disconnected from the big cluster, it is
considered a fragment, and counted. The results also indicate the existence of
the quoted crossover in the fragment-size distribution.Comment: 6 pages, 3 figure
Independent Eigenstates of Angular Momentum in a Quantum N-body System
The global rotational degrees of freedom in the Schr\"{o}dinger equation for
an -body system are completely separated from the internal ones. After
removing the motion of center of mass, we find a complete set of
independent base functions with the angular momentum . These are
homogeneous polynomials in the components of the coordinate vectors and the
solutions of the Laplace equation, where the Euler angles do not appear
explicitly. Any function with given angular momentum and given parity in the
system can be expanded with respect to the base functions, where the
coefficients are the functions of the internal variables. With the right choice
of the base functions and the internal variables, we explicitly establish the
equations for those functions. Only (3N-6) internal variables are involved both
in the functions and in the equations. The permutation symmetry of the wave
functions for identical particles is discussed.Comment: 24 pages, no figure, one Table, RevTex, Will be published in Phys.
Rev. A 64, 0421xx (Oct. 2001
ERP correlates of error processing during performance on the HalsteadCategory Test
The Halstead Category Test (HCT) is a neuropsychological test that measures a person's ability to formulate and
apply abstract principles. Performance must be adjusted based on feedback after each trial and errors are
common until the underlying rules are discovered. Event-related potential (ERP) studies associated with the HCT
are lacking. This paper demonstrates the use of amethodology inspired on Singular SpectrumAnalysis (SSA) applied
to EEG signals, to remove high amplitude ocular andmovement artifacts during performance on the test. This filtering
technique introduces no phase or latency distortions, with minimum loss of relevant EEG information. Importantly,
the test was applied in its original clinical format, without introducing adaptations to ERP recordings. After
signal treatment, the feedback-related negativity (FRN) wave, which is related to error-processing, was identified.
This component peaked around 250ms, after feedback, in fronto-central electrodes. As expected, errors elicited
more negative amplitudes than correct responses. Results are discussed in terms of the increased clinical potential
that coupling ERP informationwith behavioral performance data can bring to the specificity of theHCT in diagnosing
different types of impairment in frontal brain function.info:eu-repo/semantics/publishedVersio
Energy optimization of supplied flows from multiple pumping stations in water distributions networks
[EN] One of the most important concerns within the field of urban hydraulic engineers is the right management of water resources. When there is more than one water source, there is a question that must be answered: How much water should be provided by each water
source according to the demand curve of the network? This work proposes a methodology that solves this question. It involves an
energy analysis of the water network based on the concept of the setpoint curve. The setpoint curve gives, for every supplied flow,
the minimum head needed to satisfy pressure requirements in the network. In this sense, the setpoint curve of every source relates
two variables: supplied flow and minimum required head. Energy consumption in every source is evaluated by means of the product
of these two variables. Then flow distribution among sources is optimized and minimum heads are obtained from the setpoint
curve. The optimization process has been validated in two different ways. On one hand, a discrete method has been used, where a predefined combination of flow distributions are evaluated. On the other hand, the solution is found by means of Hooke-Jeeves and Nelder-Mead optimization algorithms. To apply these methods EPANET and its Toolkit has been applied to the mathematical model of the network. The optimization process can be applied to networks models with and without leakages. Finally, the
methodology is applied to two cases, one academic network and real network where maximum flow limitations of every source were also taken into account.León Celi, CF.; Iglesias Rey, PL.; Martínez-Solano, FJ. (2017). Energy optimization of supplied flows from multiple pumping stations in water distributions networks. Procedia Engineering. 186:93-100. doi:10.1016/j.proeng.2017.03.214S9310018
Synthesis of Chromen[4,3-b]pyrrolidines by Intramolecular 1,3-Dipolar Cycloadditions of Azomethine Ylides: An Experimental and Computational Assessment of the Origin of Stereocontrol
Azomethine ylides, generated from imine-derived O-cinnamyl or O-crotonyl salicylaldeyde and α-amino acids, undergo intramolecular 1,3-dipolar cycloaddition, leading to chromene[4,3-b]pyrrolidines. Two reaction conditions are used: (a) microwave-assisted heating (200 W, 185 °C) of a neat mixture of reagents, and (b) conventional heating (170 °C) in PEG-400 as solvent. In both cases, a mixture of two epimers at the α-position of the nitrogen atom in the pyrrolidine nucleus was formed through the less energetic endo-approach (B/C ring fusion). In many cases, the formation of the stereoisomer bearing a trans-arrangement into the B/C ring fusion was observed in high proportions. Comprehensive computational and kinetic simulation studies are detailed. An analysis of the stability of transient 1,3-dipoles, followed by an assessment of the intramolecular pathways and kinetics are also reported.Financial support was provided by the Brasilian Universiade Federal do Rio de Janeiro (UFRJ), the Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ) and the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), by the Spanish Ministerio de Ciencia e Innovación (MICINN) (projects CTQ2010-20387, Consolider Ingenio 2010, CSD2007-00006), the Spanish Ministerio de Economía y Competitividad (MINECO) (projects CTQ2013-43446-P, CTQ2014-51912-REDC, and CTQ2013-45415-P), the Fondos Europeos para el Desarrollo Regional (FEDER), the Generalitat Valenciana (PROMETEO 2009/039 and PROMETEOII/2014/017), the Basque Government (GV/EJ, grant IT-324-07), and the Universities of Alicante and of the Basque Country (UPV/EHU) (UFI11/22 QOSYC)
USE OF COMBINATION OF FLUORESCENT PROBES TO IDENTIFY SPERM SUBPOPULATIONS FOR QUALITY ASSESSMENT OF FRESH AND CRYOPRESERVED CANINE SEMEN. PRELIMINARY RESULTS
The use of fluorescent markers in the evaluation of sperm morphophysiology allows a better accuracy, compared to the subjective nature of some routine tests in semen qualification. In this study was used the combination of fluorescence probes: propionate iodide, Hoechst 33342 and FITC-PSA in fresh and thawed dog semen, to the identification of the following morphological subpopulations: II (intact plasma and acrosomal membranes), IL (intact plasma membrane and lesioned acrosomal membrane), LI (lesioned plasma membrane and intact acrosomal membrane) and LL (both membranes lesioned). When comparing the results obtained with the results of the tests used conventionally in semen evaluation (sperm motility and vigor, hypoosmotic test and morphological alterations), little correlation was observed. The II population declined from fresh semen to thawed, while LL population increased (p <0.05). The IL population was composed of extremely small numbers of cells but increased (p <0.05) from fresh semen to thawed semen. In the thawed semen the major defects had a positive correlation with the LL population (p <0.01). For the thawed semen, the results of the hypoosmotic test (number of cells that reacted to the medium) correlated positively with population II (p <0.025), that is, different from that observed in fresh semen. Although all tests were able to detect decrease in sperm quality post-thawing (p <0.05). The use of this fluorescent probe association allowed qualification and more accurately quantification of plasma membrane and acrosomal insults mediated by cryopreservation. El uso de marcadores fluorescentes en la evaluación de la morfofisiología espermática permite una mayor precisión, comparada con la naturaleza subjetiva de algunas pruebas de rutina en la valoración del semen. En este estudio se usó la combinación de pruebas fluorescentes: yoduro de propidio; Hoechst 33342 y FITC-PSA en semen fresco y descongelado de perro, para la identificación de las siguientes subpoblaciones morfológicas: II (membranas plasmática y acrosomal intactas), IL (membrana plasmática intacta y membrana acrosomal dañada), LI (membrana plasmática dañada y membrana acrosomal intacta) y LL (ambas membranas dañadas). Cuando se comparan los resultados obtenidos con los resultados de las pruebas usadas convencionalmente en la evaluación seminal (motilidad y vigor espermáticos, prueba hipoosmótica y alteraciones morfológicas), se observó poca correlación. La población II disminuyó desde el semen fresco al descongelado, mientras que la población LL se incrementó (p<0.05). la población IL estuvo compuesta por un número extremadamente pequeño de células, pero incremento (p<0.05) desde el semen fresco al descongelado. En el semen descongelado los defectos mayores tuvieron una correlación positiva con la población LL (p<0.01). En el semen descongelado, los resultados de la prueba hipoosmótica (número de células que reaccionan al medio) se correlacionaron positivamente con la población II (p<0.05). El uso de esta asociación de pruebas fluorescentes permitió la valoración y la cuantificación más precisa de los daños a la membrana plasmática y acrosomal mediados por la criopreservación.
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