Globular clusters and galaxy halos

International Nuclear Information System (INIS)

Van Den Bergh, S.

1984-01-01

Using semipartial correlation coefficients and bootstrap techniques, a study is made of the important features of globular clusters with respect to the total number of galaxy clusters and dependence of specific galaxy cluster on parent galaxy type, cluster radii, luminosity functions and cluster ellipticity. It is shown that the ellipticity of LMC clusters correlates significantly with cluster luminosity functions, but not with cluster age. The cluter luminosity value above which globulars are noticeably flattened may differ by a factor of about 100 from galaxy to galaxy. Both in the Galaxy and in M31 globulars with small core radii have a Gaussian distribution over luminosity, whereas clusters with large core radii do not. In the cluster systems surrounding the Galaxy, M31 and NGC 5128 the mean radii of globular clusters was found to increase with the distance from the nucleus. Central galaxies in rich clusters have much higher values for specific globular cluster frequency than do other cluster ellipticals, suggesting that such central galaxies must already have been different from normal ellipticals at the time they were formed

Desempenho de motor ciclo Diesel em bancada dinamométrica utilizando misturas diesel/biodiesel Performance of cycle Diesel engine in dynamometer using diesel/biodiesel mixtures

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Marcio Castellanelli

2008-03-01

Full Text Available Diante da previsão de escassez do petróleo, o éster etílico (biodiesel tem-se apresentado como excelente opção de combustível alternativo para motores ciclo Diesel. As características do biodiesel são semelhantes às do diesel em termos de viscosidade e poder calorífico, podendo ser utilizado sem adaptações nos motores. Para a realização deste trabalho, utilizou-se de motor ciclo Diesel, de injeção direta, com quatro cilindros, sem adaptações. O motor foi acoplado a um dinamômetro e sistemas de aquisição de dados auxiliares. Avaliaram-se os desempenhos de torque, de potência e de consumo específico de combustível para as seguintes misturas diesel/éster etílico de soja: B2, B5, B10, B20, B50, B75 e B100. O melhor desempenho registrado deu-se com a mistura B20.Given the prediction of the scarcity of oil, the ethyl ester (biodiesel has presented as an excellent alternative fuel option for cycle diesel engine. The characteristics of biodiesel are similar of diesel in terms of viscosity and the calorific power, being able to be used without adaptations in the engines. For the accomplishment of this work it was used a cycle diesel engine, of direct injection with four cylinders, without adaptations. The engine was connected to a dynamometer and acquisition systems of auxiliary data. The performances of torque, power and specific fuel consumption for the following mixtures diesel/soy ethyl ester had been evaluated: B2, B5, B10, B20, B50, B75 and B100. The best registered performance was given with the B20 mixture.

MISTURAS DE HERBICIDAS: EFEITOS DE ADJUVANTES NO CONTROLE DE PLANTAS INFESTANTES NA CULTURA DA SOJA

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VALDEMIR ANTONIO PERESSIN

1997-01-01

Full Text Available Estudaram-se efeitos de misturas de graminicidas com latifolicidas, aplicados em pós-emergência, acrescidos ou não de seus respectivos adjuvantes, no controle de plantas infestantes na cultura da soja (Glycine max (L. Merrill cv. IAC-8, em condições de campo. Os tratamentos consistiram em quatro graminicidas (haloxifop-metil, HM; sethoxydim, S; quizalofop-etil, QE e fluazifop-p-butil, FpB e quatro latifolicidas (chlorimuron-etil, CE; fomesafen, Fom; fluoroglycofen, Flu e lactofen, Lac, aplicados isoladamente e em misturas, além das testemunhas com e sem convivência da cultura com a comunidade infestante. Os resultados mostraram que os adjuvantes, de maneira geral, intensificaram a injúria dos herbicidas. Os graminicidas mais eficazes, aplicados isoladamente ou em misturas, no controle de Eleusine indica e de monocotiledôneas, foram HM, QE e FpB. Não houve diferenças significativas no controle de Digitaria horizontalis entre os quatro graminicidas isolados; porém, as melhores misturas foram as que utilizaram os graminicidas QE ou HM. Para controle de Mollugo verticillata, os melhores tratamentos foram obtidos com Lac aplicado isoladamente e com as misturas de QE, S ou HM com Fom e seus respectivos adjuvantes. As misturas de tanque apresentaram efeitos predominantemente antagonísticos no controle de E. indica, D. horizontalis e monocotiledôneas. Efeitos estatis-ticamente antagonísticos e sinergísticos no controle de M. verticillata foram obtidos, respec-tivamente, nas misturas de tanque com Lac e com Fom. Uma possível interação entre os adjuvantes e as misturas de herbicidas ocorreu nas avaliações de controle para E. indica, quando as misturas de S ou de HM foram usadas com ou sem adjuvantes. Os tratamentos com herbicidas não influíram na produção do cultivar de soja IAC-8.Mixtures of narrowleaf and broadleaf herbicides, with or without their respective surfactants, were evaluated as to postemergence selectivity for weed

Pregalactic formation of globular clusters in cold dark matter

International Nuclear Information System (INIS)

Faber, S.M.; Blumenthal, G.R.; Rosenblatt, E.I.

1988-01-01

The pregalactic hypothesis for the formation of globular clusters is reconsidered in the light of Zinn's (1985) discovery of a two-component globular population in the Milky Way. For a cold dark matter spectrum, high-sigma fluctuations of 10 to the 5th - 10 to the 6th solar masses are assumed to be the progenitors of the spheroidal population of globular clusters. The mass fraction of globular clusters in galaxies then requires that perturbations above roughly 2.8 sigma survive as globulars, and their observed radii require baryonic collapse factors of order 10. Such an absolute density threshold for globular cluster formation achieves adequate fits to observed cluster radii and densities, the mass fraction of globulars versus Hubble type, the radial density profile of globulars within galaxies, and the globular luminosity function. However, a fixed density threshold criterion for cluster survival lacks convincing physical justification and does not by itself explain the homogeneous metallicities within clusters or the large metallicity variations from cluster to cluster and from galaxy to galaxy. 33 references

Globular Clusters for Faint Galaxies

Science.gov (United States)

Kohler, Susanna

2017-07-01

The origin of ultra-diffuse galaxies (UDGs) has posed a long-standing mystery for astronomers. New observations of several of these faint giants with the Hubble Space Telescope are now lending support to one theory.Faint-Galaxy MysteryHubble images of Dragonfly 44 (top) and DFX1 (bottom). The right panels show the data with greater contrast and extended objects masked. [van Dokkum et al. 2017]UDGs large, extremely faint spheroidal objects were first discovered in the Virgo galaxy cluster roughly three decades ago. Modern telescope capabilities have resulted in many more discoveries of similar faint galaxies in recent years, suggesting that they are a much more common phenomenon than we originally thought.Despite the many observations, UDGs still pose a number of unanswered questions. Chief among them: what are UDGs? Why are these objects the size of normal galaxies, yet so dim? There are two primary models that explain UDGs:UDGs were originally small galaxies, hence their low luminosity. Tidal interactions then puffed them up to the large size we observe today.UDGs are effectively failed galaxies. They formed the same way as normal galaxies of their large size, but something truncated their star formation early, preventing them from gaining the brightness that we would expect for galaxies of their size.Now a team of scientists led by Pieter van Dokkum (Yale University) has made some intriguing observations with Hubble that lend weight to one of these models.Globulars observed in 16 Coma-cluster UDGs by Hubble. The top right panel shows the galaxy identifications. The top left panel shows the derived number of globular clusters in each galaxy. [van Dokkum et al. 2017]Globulars GaloreVan Dokkum and collaborators imaged two UDGs with Hubble: Dragonfly 44 and DFX1, both located in the Coma galaxy cluster. These faint galaxies are both smooth and elongated, with no obvious irregular features, spiral arms, star-forming regions, or other indications of tidal interactions

Biodegradabilidade e propriedades mecânicas de novas misturas poliméricas

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Rosa Derval S.

2001-01-01

Full Text Available O plástico tem sido cada vez mais usado em nosso cotidiano em diversos tipos de produtos: garrafas, embalagens, automóveis, etc. Diversas alternativas têm sido buscadas para minimizar o impacto ambiental causado pelos polímeros convencionais. Uma importante alternativa é o uso de polímeros biodegradáveis, que podem ser degradados pela ação de microorganismos, tais como bactérias, fungos ou algas. As aplicações tecnológicas de polímeros biodegradáveis normalmente requerem melhorias nas suas propriedades mecânicas. Neste contexto, novas misturas poliméricas vêm sendo obtidas para aplicações inovadoras e mais baratas. Neste trabalho, será apresentada a metodologia de preparação de novas misturas poliméricas, contendo diferentes teores de amido, com Policaprolactona (PCL, Polihidróxibutirato (PHB e um copolímero Poli(hidróxibutirato-co-valerato (PHBV. A resistência à tração das blendas com 50% em massa de amido é 35% e 60% menor do que a dos polímeros PCL e PHBV puros, respectivamente. Quando expostas a microorganismos em lodo ativado, as misturas de PCL ou PHBV com maiores dosagens de amido apresentam maiores taxas de degradação.

Desempenho de misturas de areia asfalto usinadas a quente com o uso de ligantes mais consistentes

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Daniel Rodrigues Aldigueri

2009-12-01

Full Text Available

Neste trabalho são apresentados resultados de uma pesquisa realizada em laboratório sobre o comportamento mecânico de uma areia asfalto usinada a quente, utilizada no revestimento de uma rodovia no estado do Ceará. A areia asfalto é uma mistura freqüentemente usada nas regiões Norte e Nordeste. Este tipo de mistura pode apresentar um desempenho similar aos concretos asfálticos recomendados para revestimentos de pavimentos em vias com alto volume de tráfego. Necessita-se, para tanto, observar sua graduação, forma de grãos e tipo e teor de ligante asfáltico a ser empregado para garantir durabilidade e resistência adequadas. As misturas pesquisadas no presente estudo têm o mesmo tipo de agregado e graduação, diferindo no teor e tipo de ligante.

Gamma-ray Emission from Globular Clusters

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Pak-Hin T. Tam

2016-03-01

Full Text Available Over the last few years, the data obtained using the Large Area Telescope (LAT aboard the Fermi Gamma-ray Space Telescope has provided new insights on high-energy processes in globular clusters, particularly those involving compact objects such as MilliSecond Pulsars (MSPs. Gamma-ray emission in the 100 MeV to 10 GeV range has been detected from more than a dozen globular clusters in our galaxy, including 47 Tucanae and Terzan 5. Based on a sample of known gammaray globular clusters, the empirical relations between gamma-ray luminosity and properties of globular clusters such as their stellar encounter rate, metallicity, and possible optical and infrared photon energy densities, have been derived. The measured gamma-ray spectra are generally described by a power law with a cut-off at a few gigaelectronvolts. Together with the detection of pulsed γ-rays from two MSPs in two different globular clusters, such spectral signature lends support to the hypothesis that γ-rays from globular clusters represent collective curvature emission from magnetospheres of MSPs in the clusters. Alternative models, involving Inverse-Compton (IC emission of relativistic electrons that are accelerated close to MSPs or pulsar wind nebula shocks, have also been suggested. Observations at >100 GeV by using Fermi/LAT and atmospheric Cherenkov telescopes such as H.E.S.S.-II, MAGIC-II, VERITAS, and CTA will help to settle some questions unanswered by current data.

CVs and millisecond pulsar progenitors in globular clusters

Science.gov (United States)

Grindlay, J. E.; Cool, A. M.; Bailyn, C. D.

1991-01-01

The recent discovery of a large population of millisecond pulsars in globular clusters, together with earlier studies of both low luminosity X-ray sources and LMXBs in globulars, suggest there should be significant numbers of CVs in globulars. Although they have been searched for without success in selected cluster X-ray source fields, systematic surveys are lacking and would constrain binary production and both stellar and dynamical evolution in globular clusters. We describe the beginnings of such a search, using narrow band H-alpha imaging, and the sensitivities it might achieve.

Globular Clusters Shine in a Galaxy Lacking Dark Matter

Science.gov (United States)

Kohler, Susanna

2018-04-01

You may have seen recent news about NGC 1052DF2, a galaxy that was discovered to have little or no dark matter. Now, a new study explores what NGC 1052DF2 does have: an enigmatic population of unusually large and luminous globular clusters.Keck/LRIS spectra (left and right) and HST images (center) of the 11 clusters associated with NGC 1052DF2. The color images each span 1 1. [van Dokkum et al. 2018]An Unusual DwarfThe ultra-diffuse galaxy NGC 1052DF2, originally identified with the Dragonfly Telescope Array, has puzzled astronomers since the discovery that its dynamical mass determined by the motions of globular-cluster-like objects spotted within it is essentially the same as its stellar mass. This equivalence implies that the galaxy is strangely lacking dark matter; the upper limit set on its dark matter halo is 400 times smaller than what we would expect for such a dwarf galaxy.Led by Pieter van Dokkum (Yale University), the team that made this discovery has now followed up with detailed Hubble Space Telescope imaging and Keck spectroscopy. Their goal? To explore the objects that allowed them to make the dynamical-mass measurement: the oddly bright globular clusters of NGC 1052DF2.Sizes (circularized half-light radii) vs. absolute magnitudes for globular clusters in NGC1052DF2 (black) and the Milky Way (red). [Adapted from van Dokkum et al. 2018]Whats Up with the Globular Clusters?Van Dokkum and collaborators spectroscopically confirmed 11 compact objects associated with the faint galaxy. These objects are globular-cluster-like in their appearance, but the peak of their luminosity distribution is offset by a factor of four from globular clusters of other galaxies; these globular clusters are significantly brighter than is typical.Using the Hubble imaging, the authors determined that NGC 1052DF2s globular clusters are more than twice the size of the Milky Ways globular clusters in the same luminosity range. As is typical for globular clusters, they are an old

Misturas binárias e ternárias de gorduras hidrogenadas e óleo de soja

OpenAIRE

SIMÕES,Ilka Sumiyoshi; GIOIELLI,Luiz Antonio; OLIVEIRA,Maricê Nogueira

1997-01-01

Na formulação de produtos gordurosos, é comum a mistura de óleos e gorduras, para se alcançar as especificações do produto final. As interações que ocorrem entre os triacilgliceróis nas misturas promovem alterações nas propriedades físicas das gorduras. Comparado às técnicas tradicionais, os experimentos planejados poupam tempo e recursos, identificam pontos ótimos verdadeiros, e permitem que os efeitos das variáveis individuais ou interações entre elas sejam determinados. O objetivo do traba...

Incompatibilidade física de misturas entre herbicidas e inseticidas Physical incompatibility of herbicide and insecticide mixtures

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F.A. Petter

2012-06-01

Full Text Available Objetivou-se, com este trabalho, avaliar a interação física entre misturas em tanque de diferentes classes de defensivos agrícolas. O experimento foi conduzido no laboratório de Química da Universidade do Estado de Mato Grosso, no período de junho a agosto de 2010. Os tratamentos foram constituídos pelas misturas de seis herbicidas (glyphosate SC, glyphosate WG, lactofen CE, fomesafen SC, haloxifop-R CE e fluazifop-pbutil EW com seis inseticidas (methomyl CS, clorpirifós CE, teflubenzuron SC, triflumuron SC, cipermetrina CE e tiametoxam + lambda-cialotrina SC na ausência e presença de dois redutores de pH (ácido pirolenhoso e ácido bórico, com quatro repetições. Utilizou-se escala de 1 a 5, visando avaliar o grau de incompatibilidade, em que 1 é a separação imediata da mistura e recomenda-se não aplicar e 5 é a homogeneidade das misturas. As maiores incompatibilidades físicas nas misturas de herbicidas e inseticidas foram observadas na presença dos herbicidas glyphosate na formulação WG e lactofen CE. O ácido pirolenhoso e o ácido bórico demonstraram ser boas alternativas, como redutores de pH, no preparo de calda de pulverização com misturas de herbicidas e inseticidas. Devem-se evitar misturas em tanque de glyphosate na formulação SC + clorpirifós CE e lactofen CE + clorpirifós CE.The objective ofthis study was to evaluate the physical interaction between simulated tank mixtures of different classes of pesticides. The experiment was conducted at the Chemistry Laboratory of the University of Mato Grosso, Brazil, from June to August 2010. The treatments consisted of mixtures of six herbicides (glyphosate SC, glyphosate WG, lactofen CE, fomesafen SC, haloxifop-R CE, and fluazifop-p-butyl EW with six types of insecticide (methomyl CS, clorpirifos CE, teflubenzuron SC, triflumuron SC, cipermetrin CE, and tiametoxam + lambda-cialotrin SC in the absence and presence oftwo pH reducers (pyroligneous acid and boric acid

Reconstructing galaxy histories from globular clusters.

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West, Michael J; Côté, Patrick; Marzke, Ronald O; Jordán, Andrés

2004-01-01

Nearly a century after the true nature of galaxies as distant 'island universes' was established, their origin and evolution remain great unsolved problems of modern astrophysics. One of the most promising ways to investigate galaxy formation is to study the ubiquitous globular star clusters that surround most galaxies. Globular clusters are compact groups of up to a few million stars. They generally formed early in the history of the Universe, but have survived the interactions and mergers that alter substantially their parent galaxies. Recent advances in our understanding of the globular cluster systems of the Milky Way and other galaxies point to a complex picture of galaxy genesis driven by cannibalism, collisions, bursts of star formation and other tumultuous events.

Nova-driven winds in globular clusters

International Nuclear Information System (INIS)

Scott, E.H.; Durisen, R.H.

1978-01-01

Recent sensitive searches for Hα emission from ionized intracluster gas in globular clusters have set upper limits that conflict with theoretical predictions. We suggest that nova outbursts heat the gas, producing winds that resolve this discrepancy. The incidence of novae in globular clusters, the conversion of kinetic energy of the nova shell to thermal energy of the intracluster gas, and the characteristics of the resultant winds are discussed. Calculated emission from the nova-driven models does not conflict with any observations to date. Some suggestions are made concerning the most promising approaches for future detection of intracluster gas on the basis of these models. The possible relationship of nova-driven winds of globular cluster X-ray sources is also considered

Avaliação de processos de misturas de concretos com agregados graúdos reciclados

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Luciana de Nazaré Pinheiro Cordeiro

Full Text Available Resumo A reutilização dos resíduos de construção civil vem sendo uma estratégia do setor para alcançar a sustentabilidade, mesmo sendo aplicada em um pequeno volume de obras. A variabilidade do resíduo de concreto é uma condição inerente do produto, que precisa ser levada em consideração, e o controle do processo produtivo de concretos produzidos com resíduos de concreto pode ser uma maneira de majorar a qualidade do compósito final. Nesse sentido, este artigo tem por objetivo avaliar a eficiência do processo de mistura e do tipo de misturador ante a fragilidade do desempenho de concretos com agregados graúdos reciclados de concreto e verificar a influência na resistência à compressão. Como objetivo específico tem-se o efeito do misturador no desempenho do concreto. O agregado graúdo reciclado de concreto foi usado em substituição total ao agregado graúdo natural. E os resultados mostraram que não há diferença significativa entre os concretos produzidos a partir de diferentes ordens de misturas; ambas promoveram resultados satisfatórios de resistência à compressão na idade de 28 dias. Porém, as misturas realizadas em misturador de eixo vertical se mostraram mais eficientes que as misturas produzidas em betoneiras de eixo inclinado, uma vez que os concretos produzidos pelas primeiras se mostram com menor coeficiente de variação. Acredita-se que as características do equipamento contribuíram para uma melhor homogeneidade, levando à menor variabilidade nos resultados do concreto.

Shaping Globular Clusters with Black Holes

Science.gov (United States)

Kohler, Susanna

2018-03-01

How many black holes lurk within the dense environments of globular clusters, and how do these powerful objects shape the properties of the cluster around them? One such cluster, NGC 3201, is now helping us to answer these questions.Hunting Stellar-Mass Black HolesSince the detection of merging black-hole binaries by the Laser Interferometer Gravitational-Wave Observatory (LIGO), the dense environments of globular clusters have received increasing attention as potential birthplaces of these compact binary systems.The central region of the globular star cluster NGC 3201, as viewed by Hubble. The black hole is in orbit with the star marked by the blue circle. [NASA/ESA]In addition, more and more stellar-mass black-hole candidates have been observed within globular clusters, lurking in binary pairs with luminous, non-compact companions. The most recent of these detections, found in the globular cluster NGC 3201, stands alone as the first stellar-mass black hole candidate discovered via radial velocity observations: the black holes main-sequence companion gave away its presence via a telltale wobble.Now a team of scientists led by Kyle Kremer (CIERA and Northwestern University) is using models of this system to better understand the impact that black holes might have on their host clusters.A Model ClusterThe relationship between black holes and their host clusters is complicated. Though the cluster environment can determine the dynamical evolution of the black holes, the retention rate of black holes in a globular cluster (i.e., how many remain in the cluster when they are born as supernovae, rather than being kicked out during the explosion) influences how the host cluster evolves.Kremer and collaborators track this complex relationship by modeling the evolution of a cluster similar to NGC 3201 with a Monte Carlo code. The code incorporates physics relevant to the evolution of black holes and black-hole binaries in globular clusters, such as two-body relaxation

Dinamical properties of globular clusters: Primordial or evolutional?

Science.gov (United States)

Surdin, V. G.

1995-04-01

Some observable relations between globular cluster parameters appear as a result of dynamical evolution of the cluster system. These relations are inapplicable to the studies of the globular cluster origin

GLOBULAR CLUSTERS AS CRADLES OF LIFE AND ADVANCED CIVILIZATIONS

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Stefano, R. Di [Harvard-Smithsonian Center for Astrophysics (United States); Ray, A., E-mail: rdistefano@cfa.harvard.edu, E-mail: akr@tifr.res.in [Tata Institute of Fundamental Research (India)

2016-08-10

Globular clusters are ancient stellar populations in compact dense ellipsoids. There is no star formation and there are no core-collapse supernovae, but several lines of evidence suggest that globular clusters are rich in planets. If so, and if advanced civilizations can develop there, then the distances between these civilizations and other stars would be far smaller than typical distances between stars in the Galactic disk, facilitating interstellar communication and travel. The potent combination of long-term stability and high stellar densities provides a globular cluster opportunity. Yet the very proximity that promotes interstellar travel also brings danger, as stellar interactions can destroy planetary systems. We find, however, that large portions of many globular clusters are “sweet spots,” where habitable-zone planetary orbits are stable for long times. Globular clusters in our own and other galaxies are, therefore, among the best targets for searches for extraterrestrial intelligence (SETI). We use the Drake equation to compare the likelihood of advanced civilizations in globular clusters to that in the Galactic disk. We also consider free-floating planets, since wide-orbit planets can be ejected to travel through the cluster. Civilizations spawned in globular clusters may be able to establish self-sustaining outposts, reducing the probability that a single catastrophic event will destroy the civilization. Although individual civilizations may follow different evolutionary paths, or even be destroyed, the cluster may continue to host advanced civilizations once a small number have jumped across interstellar space. Civilizations residing in globular clusters could therefore, in a sense, be immortal.

GLOBULAR CLUSTERS AS CRADLES OF LIFE AND ADVANCED CIVILIZATIONS

International Nuclear Information System (INIS)

Stefano, R. Di; Ray, A.

2016-01-01

Globular clusters are ancient stellar populations in compact dense ellipsoids. There is no star formation and there are no core-collapse supernovae, but several lines of evidence suggest that globular clusters are rich in planets. If so, and if advanced civilizations can develop there, then the distances between these civilizations and other stars would be far smaller than typical distances between stars in the Galactic disk, facilitating interstellar communication and travel. The potent combination of long-term stability and high stellar densities provides a globular cluster opportunity. Yet the very proximity that promotes interstellar travel also brings danger, as stellar interactions can destroy planetary systems. We find, however, that large portions of many globular clusters are “sweet spots,” where habitable-zone planetary orbits are stable for long times. Globular clusters in our own and other galaxies are, therefore, among the best targets for searches for extraterrestrial intelligence (SETI). We use the Drake equation to compare the likelihood of advanced civilizations in globular clusters to that in the Galactic disk. We also consider free-floating planets, since wide-orbit planets can be ejected to travel through the cluster. Civilizations spawned in globular clusters may be able to establish self-sustaining outposts, reducing the probability that a single catastrophic event will destroy the civilization. Although individual civilizations may follow different evolutionary paths, or even be destroyed, the cluster may continue to host advanced civilizations once a small number have jumped across interstellar space. Civilizations residing in globular clusters could therefore, in a sense, be immortal.

Interactions between globular proteins and F-actin in isotonic saline solution.

Science.gov (United States)

Lakatos, S; Minton, A P

1991-10-05

Solutions of each of three different globular proteins (cytochrome c, chromophorically labeled serum albumin, and chromophorically labeled aldolase), mixed with another unlabeled globular protein or with fibrous actin, were prepared in pH 8.0 Tris-HCl buffer containing 0.15 M NaCl. Each solution was centrifuged at low speed, at 5 degrees C, until unassociated globular protein in solution achieved sedimentation equilibrium. Individual absorbance gradients of both macrosolutes in the mixtures subsequent to centrifugation were obtained via optical scans of the centrifuge tubes at two wavelengths. The gradients of each macrosolute in mixtures of two globular proteins revealed no association of globular proteins under the conditions of these experiments, but perturbation of the gradients of serum albumin, aldolase, and cytochrome c in the presence of F-actin indicated association of all three globular proteins with F-actin. Perturbation of actin gradients in the presence of serum albumin and aldolase suggested partial depolymerization of the F-actin by the globular protein. Analysis of the data with a simple phenomenological model relating free globular protein, bound globular protein, and total actin concentration provided estimates of the respective equilibrium constants for association of serum albumin and aldolase with F-actin, under the conditions of these experiments, of the order of 0.1 microM-1.

Search for optical millisecond pulsars in globular clusters

International Nuclear Information System (INIS)

Middleditch, J.H.; Imamura, J.N.; Steiman-Cameron, T.Y.

1988-01-01

A search for millisecond optical pulsars in several bright, compact globular clusters was conducted. The sample included M28, and the X-ray clusters 47 Tuc, NGC 6441, NGC 6624, M22, and M15. The globular cluster M28 contains the recently discovered 327 Hz radio pulsar. Upper limits of 4 sigma to pulsed emission of (1-20) solar luminosities were found for the globular clusters tested, and 0.3 solar luminosity for the M28 pulsar for frequencies up to 500 Hz. 8 references

Misturas de forrageiras anuais e perenes para sucessão à soja em sistemas de integração lavoura‑pecuária

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Luís Armando Zago Machado

2012-04-01

Full Text Available O objetivo deste trabalho foi avaliar a produção de forragem de espécies perenes e de suas misturas com espécies anuais, durante a estação seca, e a produtividade de grãos de soja cultivada em sucessão. Os experimentos foram realizados em 2007 e 2008, em Dourados e em São Gabriel do Oeste, MS. Em 2007, foram avaliadas as espécies Urochloa brizantha ('Xaraés' e Megathyrsus maximus ('Tanzânia', em cultivos solteiros ou em misturas com Eleusine coracana (capim‑pé‑de‑galinha, Pennisetum glaucum (milheto e Sorghum bicolor (sorgo forrageiro. Em 2008, foram avaliados U. decumbens e as cultivares Xaraés e Tanzânia em cultivos solteiros ou em misturas com milheto e sorgo forrageiro. As forrageiras foram avaliadas sob sucessivos cortes, durante a estação seca, e a soja no verão, no cultivo em sucessão. As misturas de espécies anuais e perenes não aumentam a produção de forragem, mas melhoram sua distribuição ao longo da estação seca. As forrageiras anuais têm maior participação na produção de forragem das misturas no início da estação seca, e as perenes no final dessa estação. A relação folha/colmo das forrageiras perenes individuais é maior do que a das misturas. Os tratamentos avaliados não têm efeito sobre a soja cultivada em sucessão.

New VVV Survey Globular Cluster Candidates in the Milky Way Bulge

Energy Technology Data Exchange (ETDEWEB)

Minniti, Dante; Gómez, Matías [Departamento de Física, Facultad de Ciencias Exactas, Universidad Andrés Bello, Av. Fernandez Concha 700, Las Condes, Santiago (Chile); Geisler, Douglas; Fernández-Trincado, Jose G. [Departamento de Astronomía, Casilla 160-C, Universidad de Concepción, Casilla 160-C, Concepción (Chile); Alonso-García, Javier; Beamín, Juan Carlos; Borissova, Jura; Catelan, Marcio; Ramos, Rodrigo Contreras; Kurtev, Radostin; Pullen, Joyce [Instituto Milenio de Astrofísica, Santiago (Chile); Palma, Tali; Clariá, Juan J. [Observatorio Astronómico, Universidad Nacional de Córdoba, Laprida 854, Córdoba (Argentina); Cohen, Roger E. [Space Telescope Science Institute, 2700 San Martin Drive, Baltimore (United States); Dias, Bruno [European Southern Observatory, Alonso de Cordova 3107, Vitacura, Santiago (Chile); Hempel, Maren [Pontificia Universidad Católica de Chile, Instituto de Astrofísica, Av. Vicuña Mackenna 4860, Santiago (Chile); Ivanov, Valentin D. [European Southern Observatory, Karl-Schwarszchild-Str. 2, D-85748 Garching bei Muenchen (Germany); Lucas, Phillip W. [Dept. of Astronomy, University of Hertfordshire, Hertfordshire (United Kingdom); Moni-Bidin, Christian; Alegría, Sebastian Ramírez [Instituto de Astronomía, Universidad Católica del Norte, Antofagasta (Chile); and others

2017-11-10

It is likely that a number of Galactic globular clusters remain to be discovered, especially toward the Galactic bulge. High stellar density combined with high and differential interstellar reddening are the two major problems for finding globular clusters located toward the bulge. We use the deep near-IR photometry of the VISTA Variables in the Vía Láctea (VVV) Survey to search for globular clusters projected toward the Galactic bulge, and hereby report the discovery of 22 new candidate globular clusters. These objects, detected as high density regions in our maps of bulge red giants, are confirmed as globular cluster candidates by their color–magnitude diagrams. We provide their coordinates as well as their near-IR color–magnitude diagrams, from which some basic parameters are derived, such as reddenings and heliocentric distances. The color–magnitude diagrams reveal well defined red giant branches in all cases, often including a prominent red clump. The new globular cluster candidates exhibit a variety of extinctions (0.06 < A {sub Ks} < 2.77) and distances (5.3 < D < 9.5 kpc). We also classify the globular cluster candidates into 10 metal-poor and 12 metal-rich clusters, based on the comparison of their color–magnitude diagrams with those of known globular clusters also observed by the VVV Survey. Finally, we argue that the census for Galactic globular clusters still remains incomplete, and that many more candidate globular clusters (particularly the low luminosity ones) await to be found and studied in detail in the central regions of the Milky Way.

Photometric studies of globular clusters in the Andromeda nebula

International Nuclear Information System (INIS)

Sharov, A.S.; Lyutyj, V.M.

1983-01-01

The comparison of the frequency distribution of Bergh Q and Racine R metallicity parameters for globular clusters in the Galaxy and M31 is given. Mean values of the parameters are: in the Galaxy anti Q=-0.31 and anti R=0.40, in M31 anti Q=-0.32 and anti R=0.42. Hence the mean metallicity of globular clusters in two galaxies is identical. The differences in the observed frequency distribution of the parameters, in particular in the limits of general metallicity, are related to the random errors of photometrical measurements of globular clusters, considerably greater in the case of M31. Thereby the preference should be given to Hanes conclusion that globular clusters form a uniform population at least in two close systems. It should not be excepted that in other galaxies mean colour characteristics and hence metallicity of clusters may be of other type. Thus globular clusters related to the M31-NGC 205 satellite have somewhat minor B-V colour factors

TOWARDS THE CONCEPT OF GLOBULAR PEARLITE

OpenAIRE

A. G. Anisovich; M. K. Stepankova; A. A. Andrushevich

2016-01-01

Explanatory imprecisions of concept of globular pearlite and ferrite-carbide-mixture are considered. The need of concept binding of globular pearlite to specific grain with 0.8% carbon content is explained with the assistance of exemplary data obtained at the present metallographic equipment. The question of educational material presentation concerning the process of teaching of discipline «Materials and construction materials technology» is discussed in relation to the educational process of...

THE PRODUCTION RATE OF SN Ia EVENTS IN GLOBULAR CLUSTERS

International Nuclear Information System (INIS)

Washabaugh, Pearce C.; Bregman, Joel N.

2013-01-01

In globular clusters, dynamical evolution produces luminous X-ray emitting binaries at a rate about 200 times greater than in the field. If globular clusters also produce SN Ia at a high rate, it would account for many of the SN Ia production in early-type galaxies and provide insight into their formation. Here we use archival Hubble Space Telescope (HST) images of nearby galaxies that have hosted an SN Ia to examine the rate at which globular clusters produce these events. The location of the SN Ia is registered on an HST image obtained before the event or after the supernova (SN) faded. Of the 36 nearby galaxies examined, 21 had sufficiently good data to search for globular cluster hosts. None of the 21 SNe have a definite globular cluster counterpart, although there are some ambiguous cases. This places an upper limit to the enhancement rate of SN Ia production in globular clusters of about 42 at the 95% confidence level, which is an order of magnitude lower than the enhancement rate for luminous X-ray binaries. Even if all of the ambiguous cases are considered as having a globular cluster counterpart, the upper bound for the enhancement rate is 82 at the 95% confidence level, still a factor of several below that needed to account for half of the SN Ia events. Barring unforeseen selection effects, we conclude that globular clusters are not responsible for producing a significant fraction of the SN Ia events in early-type galaxies.

TOWARDS THE CONCEPT OF GLOBULAR PEARLITE

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A. G. Anisovich

2016-01-01

Full Text Available Explanatory imprecisions of concept of globular pearlite and ferrite-carbide-mixture are considered. The need of concept binding of globular pearlite to specific grain with 0.8% carbon content is explained with the assistance of exemplary data obtained at the present metallographic equipment. The question of educational material presentation concerning the process of teaching of discipline «Materials and construction materials technology» is discussed in relation to the educational process of technical universities, in particular, the Belarusian State Agrarian Technical University.

Desempenho de motor diesel com misturas de biodiesel de óleo de girassol Performance of diesel engine fuelled with sunflower biodiesel blends

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Ila Maria Corrêa

2008-06-01

Full Text Available Objetivou-se, neste trabalho avaliar o uso de misturas de biodiesel de girassol (Helianthus annuus L. e diesel no desempenho de um motor de ignição por compressão, injeção direta. Os ensaios foram realizados em bancada dinamométrica utilizando-se as misturas B5, B10, B20 e B100 em comparação ao diesel (D. Foi analisado o desempenho do motor através da tomada de potência (TDP com cada combustível, e analisado o óleo lubrificante do motor antes e após 96 horas de uso com B100. Os resultados obtidos foram: D (40,7 kW; 271 g/kW.h; B5 (40,3 kW; 271 g/kW.h; B10 (39,8 kW; 277 g/kW.h; B20 (40,0 kW; 277 g/kW.h e B100 (39,8 kW; 291 g/kW.h. Concluiu-se que o uso das misturas B5, B10, B20 e B100 proporcionou redução de no máximo 2,2 % na potência na TDP e um aumento máximo de 7,3 %, no consumo específico de combustível. A análise do óleo lubrificante, antes e após o uso com B100, detectou alterações aceitáveis, sendo a viscosidade, a presença de água e o teor de ferro os parâmetros mais expressivamente alterados.This work aimed to evaluate the use of sunflower biodiesel (Helianthus annuus L. blends in a CI engine, direct injection. The test procedure was carried out in a dynamometer bench that determined the performance of engine through power take-off (PTO with use of diesel and sunflower biodiesel blends (B5, B10, B20 and B100. The lubricating oil was analyzed before and after period of 96 hours. The results were: D (40,7 kW; 271 g/kW.h; B5 (40,3 kW; 271 g/kW.h; B10 (39,8 kW; 277 g/kW.h; B20 (40,0 kW; 277 g/kW.h e B100 (39,8 kW; 291 g/kW.h. One conclude that the use of blends B5, B10, B20 and B100 decreased the power of PTO max. 2,2% and increased the fuel consumption max. 7, 3%. The analysis of the lubricating oil before and after the use of B100 showed acceptable alterations and the viscosity, water content and level of iron were the most affected parameters.

Caracterização físico-química de misturas de óleos vegetais para fins alimentares.

OpenAIRE

ALMEIDA, K. M. de; MEDEIROS, E. P. de; GOMES, J. P.; SOUSA, E. P. de; SANTOS, J. W. dos

2014-01-01

Objetivou-se, com este trabalho, a elaboração e caracterização de misturas especiais de óleos vegetais para fins alimentícios, com base nos óleos de amendoim, gergelim, maracujá e soja. Os óleos de amendoim e gergelim foram extraídos de sementes das cultivares BRS-Havana e BRS-Seda, respectivamente, cedidas pela Embrapa Algodão enquanto o óleo de maracujá foi adquirido no comércio de São Paulo e o de soja no de Campina Grande. As misturas foram elaboradas com base em uma matriz de planejament...

Estabilização química do subleito de estradas: influência do tempo decorrido entre a mistura e a compactação na resistência mecânica de misturas solo-RBI Grade 81 Chemical stabilization of road subgrade: influence of elapsed time between mixture and compaction on mechanical strength of soil-RBI Grade 81 mixtures

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Tiago Pinto da Trindade

2005-06-01

Full Text Available Este artigo aborda o estudo da influência do tempo decorrido entre mistura e compactação na resistência mecânica de três solos da Zona da Mata Norte de Minas Gerais, Brasil, quando estabilizados com 4% de RBI Grade 81, em relação ao peso de solo seco. Um solo residual maduro (solo 1 e dois solos residuais jovens (solos 2 e 3 de gnáisse foram utilizados no presente estudo. O programa de ensaios de laboratório englobou: (i tempos decorridos entre mistura e compactação: 0, 4, 8 e 24 horas; (ii energia de compactação: Proctor Modificado; (iii período de cura das misturas: 7 dias; e (iv determinação da resistência mecânica: média de três determinações da resistência à compressão não-confinada. Os resultados desta pesquisa indicam que: (i o tempo decorrido entre mistura e compactação dos corpos-de-prova influenciou significativamente o parâmetro resistência à compressão não confinada das misturas; (ii 4 horas foi o tempo ótimo entre mistura e compactação para as misturas dos solos 1 e 2 com RBI Grade 81; e (iii no solo 3, foi observado um melhor resultado para a compactação imediatamente após a mistura.This paper describes the study of the influence of time between mixture and compaction in the mechanical strength of three soils from ";Zona da Mata Norte";, Minas Gerais, Brazil, stabilized with 4% of RBI Grade 81. One mature (soil 1 and two young (soils 2 and 3 gneiss residual soils were used throughout the study. The laboratory testing program consisted of the following steps: (i elapsed times between mixture and compaction: 0, 4, 8 and 24 hours; (ii mixture specimen compaction effort: Modified Proctor; (iii mixture specimen curing time: 7 days in acclimatized room; (iv determination of mechanical strength: average of three determinations of unconfined compression strength. The testing data supported that: (i the elapsed time between mixture and specimen compaction affected significantly the mixture mechanical

Pulsar-irradiated stars in dense globular clusters

Science.gov (United States)

Tavani, Marco

1992-01-01

We discuss the properties of stars irradiated by millisecond pulsars in 'hard' binaries of dense globular clusters. Irradiation by a relativistic pulsar wind as in the case of the eclipsing millisecond pulsar PSR 1957+20 alter both the magnitude and color of the companion star. Some of the blue stragglers (BSs) recently discovered in dense globular clusters can be irradiated stars in binaries containing powerful millisecond pulsars. The discovery of pulsar-driven orbital modulations of BS brightness and color with periods of a few hours together with evidence for radio and/or gamma-ray emission from BS binaries would valuably contribute to the understanding of the evolution of collapsed stars in globular clusters. Pulsar-driven optical modulation of cluster stars might be the only observable effect of a new class of binary pulsars, i.e., hidden millisecond pulsars enshrouded in the evaporated material lifted off from the irradiated companion star.

Possible systematic decreases in the age of globular clusters

Energy Technology Data Exchange (ETDEWEB)

Shi, X. [Univ. of Chicago, Chicago, IL (United States); Schramm, D. N. [Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Univ. of Chicago, Chicago, IL (United States); Dearborn, D. S.P. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Truran, J. W. [Univ. of Chicago, Chicago, IL (United States)

1994-03-01

The ages of globular clusters inferred from observations depends sensitively on assumptions like the initial helium abundance and the mass loss rate. A high helium abundance (e.g., Y\\approx0.28) or a mass loss rate of \\sim10^{-11}M_\\odot yr^{-1} near the main sequence turn-off region lowers the current age estimate from 14 Gyr to about 10--12 Gyr, significantly relaxing the constraints on the Hubble constant, allowing values as high as 60km/sec/Mpc for a universe with the critical density and 90km/sec/Mpc for a baryon-only universe. Possible mechanisms for the helium enhancement in globular clusters are discussed, as are arguments for an instability strip induced mass loss near the turn-off. Ages lower than 10 Gyr are not possible even with the operation of both of these mechanisms unless the initial helium abundance in globular clusters is >0.30, which would conflict with indirect measurements of helium abundances in globular clusters.

Glyphosate em mistura com herbicidas alternativos para o manejo de plantas daninhas Glyphosate combined with alternative herbicides for vegetation management

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P.A. Monquero

2001-12-01

Full Text Available O uso intensivo de glyphosate como herbicida não-seletivo tem selecionado espécies de plantas daninhas tolerantes. Dessa forma, é importante que sejam estudadas misturas de tanque com herbicidas de mecanismos de ação alternativos e que apresentem efeitos sinergísticos ou aditivos. Por essa razão, foi instalado um experimento inteiramente casualizado, composto por 13 tratamentos e 4 repetições, em casa de vegetação da Universidade de São Paulo - ESALQ/USP, Piracicaba-SP, com as plantas daninhas Richardia brasiliensis, Commelina benghalensis, Amaranthus hybridus, Galinsoga parviflora e Ipomoea grandifolia em misturas de tanque dos herbicidas chlorimuron-ethyl, sulfentrazone, carfentrazone, bentazon ou flumioxazin com glyphosate. As interações foram aditivas para as plantas daninhas I. grandifolia e C. benghalensis, e os herbicidas flumioxazin, sulfentrazone e carfentrazone aplicados isoladamente e em mistura com glyphosate foram os que proporcionaram os melhores níveis de controle. A interação de glyphosate com sulfentrazone foi antagônica em R. brasiliensis; a mistura de glyphosate com os demais herbicidas estudados foi aditiva, sendo os tratamentos com mistura de glyphosate e chlorimuron-ethyl ou flumioxazin os mais eficazes. Em A. hybridus, os tratamentos que apresentaram melhores níveis de controle foram o glyphosate e carfentrazone, aplicados isoladamente, e a mistura de glyphosate com flumioxazin, sulfentrazone, chlorimuron-ethyl e bentazon, sendo estes interações aditivas. No caso de G. parviflora, os tratamentos com flumioxazin e sulfentrazone apresentaram controle total, o mesmo acontecendo com as misturas de glyphosate com carfentrazone, flumioxazin, sulfentrazone, chlorimuron-ethyl ou bentazon.The intensive use of glyphosate as a non-selective herbicide for weed vegetation management has selected some tolerant weed species. Thus, it is important to study the synergistic or antagonic or additive effects of tank

Effect of the horizontal branch on the colours of globular clusters

Energy Technology Data Exchange (ETDEWEB)

Sil' chenko, O K [Moskovskij Gosudarstvennyj Univ. (USSR). Gosudarstvennyj Astronomicheskij Inst. ' ' GAISh' '

1963-05-01

The influence of the horizontal branch (HB) on the integral UBV colours of globular clusters is studied by means of statistical analysis of the colour-magnitude diagram catalogue for globular clusters of our Galaxy. The colour correction for HB is shown to be always negative. It turns out to be small for m. tal-rich globular clusters ((Fe/H)>-1.1) and independent on the HB shape for metal-poor ones.

Effect of the horizontal branch on the colours of globular clusters

International Nuclear Information System (INIS)

Sil'chenko, O.K.

1963-01-01

The influence of the horizontal branch (HB) on the integral UBV colours of globular clusters is studied by means of statistical analysis of the colour-magnitude diagram catalogue for globular clusters of our Galaxy. The colour correction for HB is shown to be always negative. It turns out to be small for m. tal-rich globular clusters ([Fe/H]>-1.1) and independent on the HB shape for metal-poor ones

The WAGGS project - I. The WiFeS Atlas of Galactic Globular cluster Spectra

Science.gov (United States)

Usher, Christopher; Pastorello, Nicola; Bellstedt, Sabine; Alabi, Adebusola; Cerulo, Pierluigi; Chevalier, Leonie; Fraser-McKelvie, Amelia; Penny, Samantha; Foster, Caroline; McDermid, Richard M.; Schiavon, Ricardo P.; Villaume, Alexa

2017-07-01

We present the WiFeS Atlas of Galactic Globular cluster Spectra, a library of integrated spectra of Milky Way and Local Group globular clusters. We used the WiFeS integral field spectrograph on the Australian National University 2.3 m telescope to observe the central regions of 64 Milky Way globular clusters and 22 globular clusters hosted by the Milky Way's low-mass satellite galaxies. The spectra have wider wavelength coverage (3300-9050 Å) and higher spectral resolution (R = 6800) than existing spectral libraries of Milky Way globular clusters. By including Large and Small Magellanic Cloud star clusters, we extend the coverage of parameter space of existing libraries towards young and intermediate ages. While testing stellar population synthesis models and analysis techniques is the main aim of this library, the observations may also further our understanding of the stellar populations of Local Group globular clusters and make possible the direct comparison of extragalactic globular cluster integrated light observations with well-understood globular clusters in the Milky Way. The integrated spectra are publicly available via the project website.

Propriedades físicas de lipídios estruturados obtidos de misturas de gordura do leite e óleo de milho

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Rodrigues Juliana Neves

2003-01-01

Full Text Available Através da mistura e interesterificação de óleos e gorduras podem ser obtidos lipídios estruturados, que são compostos que apresentam características físicas, químicas e nutricionais diferentes das dos lipídios que lhes deram origem. Esses novos compostos podem apresentar capacidade de reduzir o risco de doenças, sendo então chamados de "alimentos funcionais". O objetivo deste estudo foi avaliar as propriedades físicas de lipídios estruturados obtidos por interesterificação química a partir de misturas de gordura do leite e óleo de milho. Foram preparadas quatro misturas, nas proporções de 80:20, 60:40, 40:60 e 20:80 de gordura do leite e óleo de milho, respectivamente. As amostras foram submetidas à interesterificação química com catalisador metóxido de sódio. As misturas e os lipídios estruturados obtidos foram avaliados quanto à consistência, conteúdo de gordura sólida e composição em ácidos graxos. Foram obtidos lipídios estruturados contendo teores de até 22% de ácido linoléico pela adição de até 40% de óleo de milho à gordura do leite, que originalmente possuía apenas cerca de 2% deste ácido graxo. A consistência e o conteúdo de gordura sólida foram dependentes da gordura do leite e da interação desta com o óleo de milho. Os coeficientes relativos às interações entre os componentes das misturas foram negativos, demonstrando efeito antagônico, característico de interações eutéticas entre gorduras. Os resultados mostraram relação linear significativa entre o conteúdo de gordura sólida e a consistência das amostras.

Millisecond radio pulsars in globular clusters

Science.gov (United States)

Verbunt, Frank; Lewin, Walter H. G.; Van Paradijs, Jan

1989-01-01

It is shown that the number of millisecond radio pulsars, in globular clusters, should be larger than 100, applying the standard scenario that all the pulsars descend from low-mass X-ray binaries. Moreover, most of the pulsars are located in a small number of clusters. The prediction that Teran 5 and Liller 1 contain at least about a dozen millisecond radio pulsars each is made. The observations of millisecond radio pulsars in globular clusters to date, in particular the discovery of two millisecond radio pulsars in 47 Tuc, are in agreement with the standard scenario, in which the neutron star is spun up during the mass transfer phase.

Globular cluster metallicity scale: evidence from stellar models

International Nuclear Information System (INIS)

Demarque, P.; King, C.R.; Diaz, A.

1982-01-01

Theoretical giant branches have been constructed to determine their relative positions for metallicities in the range -2.3 0 )/sub 0,g/ based on these models is presented which yields good agreement over the observed range of metallicities for galactic globular clusters and old disk clusters. The metallicity of 47 Tuc and M71 given by this calibration is about -0.8 dex. Subject headings: clusters, globular: stars: abundances: stars: interiors

Supra-galactic colour patterns in globular cluster systems

Science.gov (United States)

Forte, Juan C.

2017-07-01

An analysis of globular cluster systems associated with galaxies included in the Virgo and Fornax Hubble Space Telescope-Advanced Camera Surveys reveals distinct (g - z) colour modulation patterns. These features appear on composite samples of globular clusters and, most evidently, in galaxies with absolute magnitudes Mg in the range from -20.2 to -19.2. These colour modulations are also detectable on some samples of globular clusters in the central galaxies NGC 1399 and NGC 4486 (and confirmed on data sets obtained with different instruments and photometric systems), as well as in other bright galaxies in these clusters. After discarding field contamination, photometric errors and statistical effects, we conclude that these supra-galactic colour patterns are real and reflect some previously unknown characteristic. These features suggest that the globular cluster formation process was not entirely stochastic but included a fraction of clusters that formed in a rather synchronized fashion over large spatial scales, and in a tentative time lapse of about 1.5 Gy at redshifts z between 2 and 4. We speculate that the putative mechanism leading to that synchronism may be associated with large scale feedback effects connected with violent star-forming events and/or with supermassive black holes.

Curvas de desempenho motor de um trator agrícola utilizando diferentes proporções de biodiesel de soja

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Vanderson Rabelo de Paula

2015-07-01

Full Text Available A crise energética, associada ao aumento da demanda por combustíveis e à crescente preocupação com o meio ambiente, tem levado à busca por fontes alternativas de energia. Além disso, a entrada de novos equipamentos e máquinas agrícolas altamente competitivos, em termos de custo, vem despertando o interesse dos agricultores. No entanto, tais equipamentos, pela sua recente inserção no mercado, ainda não apresentam parâmetros que os remetam à confiabilidade. Nesse contexto, este estudo visou ao ensaio dinamométrico de tomada de potência (TDP de um trator agrícola da marca Green Horse, modelo 204, para obtenção de suas curvas de desempenho, utilizando como combustível misturas de óleo diesel e biodiesel de soja, nas proporções B2, B5, B20 e B100. Os resultados mostraram que o trator apresentou desempenho motor compatível com outros modelos de mesma potência utilizados no país, apresentando o melhor desempenho com o uso do combustível B5.

Claro e confuso: a mistura de imagens no cinema

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Jacques Aumont

2008-11-01

Full Text Available No cinema, a mistura de imagens é um procedimento narrativo que pode ser obtido a partir da superposição de dois ou mais planos filmados. Este recurso vem sendo utilizado desde a fase do cinema mudo até os cineastas de vanguarda; pode ser facilmente observado tanto em filmes hollywoodianos quanto experimentais. Ao superpor imagens num mesmo quadro, o cinema nos obriga a pensar no estatuto e na "lógica" da imagem em movimento, estimulando-nos a entender, em última instância, o próprio processo de percepção e de constituição do sentido a partir de sua articulação no interior do plano ou entre planos. É da problemática da instauração e da apreensão perceptual e conceitual dessas imagens "misturadas" que este artigo se ocupa, valendo-se das relações possí­veis entre cinema, pintura e fotografia. Palavras-chave cinema, imagem, mistura, percepção, sentido Abstract In cinema, the dissolving of one image into another is a narrative procedure that is obtained through the juxtaposition of two or more shots. This resource has been utilized ever since the silent film era through to the vanguard filmmakers. It is present as much in Hollywood blockbusters as in experimental films. In superimposing images within a single frame, the cinema obliges us to in perceive the logic of the images in movement, leading us eventually to understand the actual process of perception and constitution of meaning through its articulation either within a single shot or between shots. This article is concerned with the issue of establishing these blended images and their perceptual, conceptual comprehension, exploring the possible relations between cinema, painting and phothograpy. Key words cinema, image, dissolve, perception, meaning

Images in the rocket ultraviolet - UV fluxes of M31 globular clusters

International Nuclear Information System (INIS)

Bohlin, R.C.; Cornett, R.H.; Hill, J.K.; Hill, R.S.; Stecher, T.P.

1988-01-01

Images obtained by a rocket-borne UV imaging telescope are used here to determine near-UV fluxes for 17 sources in M31 that are optical globular-cluster candidates and for the bright open cluster vdB0 in M31. Far-UV fluxes or flux limits are determined for the same clusters. The m(NUV)-V colors for M31 clusters are similar to those of Galactic clusters, except for the high-metallicity M31 cluster Bo 171. Four of the detected clusters have optical, m(NUV) - V, and m(FUV) - V colors indicating ages of about 100 million years. These four clusters are probably similar to the so-called 'blue globular' clusters of the LMC. The existence of young LMC-type blue globulars and the possible existence of middle-aged metal-rich globulars may indicate that M31 has continued to form globular clusters throughout its life. 39 references

Statistical interior properties of globular proteins

International Nuclear Information System (INIS)

Zhou-Ting, Jiang; Tai-Quan, Wu; Lin-Xi, Zhang; Ting-Ting, Sun

2009-01-01

The character of forming long-range contacts affects the three-dimensional structure of globular proteins deeply. As the different ability to form long-range contacts between 20 types of amino acids and 4 categories of globular proteins, the statistical properties are thoroughly discussed in this paper. Two parameters N C and N D are defined to confine the valid residues in detail. The relationship between hydrophobicity scales and valid residue percentage of each amino acid is given in the present work and the linear functions are shown in our statistical results. It is concluded that the hydrophobicity scale defined by chemical derivatives of the amino acids and nonpolar phase of large unilamellar vesicle membranes is the most effective technique to characterise the hydrophobic behavior of amino acid residues. Meanwhile, residue percentage P i and sequential residue length L i of a certain protein i are calculated under different conditions. The statistical results show that the average value of P i as well as L i of all-α proteins has a minimum among these 4 classes of globular proteins, indicating that all-α proteins are hardly capable of forming long-range contacts one by one along their linear amino acid sequences. All-β proteins have a higher tendency to construct long-range contacts along their primary sequences related to the secondary configurations, i.e. parallel and anti-parallel configurations of β sheets. The investigation of the interior properties of globular proteins give us the connection between the three-dimensional structure and its primary sequence data or secondary configurations, and help us to understand the structure of protein and its folding process well. (cross-disciplinary physics and related areas of science and technology)

Exploring the Internal Dynamics of Globular Clusters

Science.gov (United States)

Watkins, Laura L.; van der Marel, Roeland; Bellini, Andrea; Luetzgendorf, Nora; HSTPROMO Collaboration

2018-01-01

Exploring the Internal Dynamics of Globular ClustersThe formation histories and structural properties of globular clusters are imprinted on their internal dynamics. Energy equipartition results in velocity differences for stars of different mass, and leads to mass segregation, which results in different spatial distributions for stars of different mass. Intermediate-mass black holes significantly increase the velocity dispersions at the centres of clusters. By combining accurate measurements of their internal kinematics with state-of-the-art dynamical models, we can characterise both the velocity dispersion and mass profiles of clusters, tease apart the different effects, and understand how clusters may have formed and evolved.Using proper motions from the Hubble Space Telescope Proper Motion (HSTPROMO) Collaboration for a set of 22 Milky Way globular clusters, and our discrete dynamical modelling techniques designed to work with large, high-quality datasets, we are studying a variety of internal cluster properties. We will present the results of theoretical work on simulated clusters that demonstrates the efficacy of our approach, and preliminary results from application to real clusters.

Mistura reativa de poliamida 6 e policarbonato: reatividade do copolímero formado "in situ" Polyamide 6 and polycarbonate reactive blends: reactivity of the copolymer formed "in situ"

Directory of Open Access Journals (Sweden)

Dilma A. Costa

2004-01-01

Full Text Available As misturas físicas de poliamida 6 (PA6 e policarbonato (PC processadas a 240 ºC, durante 10, 30 e 60 minutos formam um copolímero de PA6-PC. A alta temperatura e o longo tempo de processamento podem causar modificações nas propriedades dessas misturas e degradar o copolímero, originando grupos isocianato e subseqüentemente CO2 e grupos NH2 terminais. A quantidade de copolímero PA6-PC formado durante o processo de mistura é maior com o aumento da proporção de PC na mistura. As ligações uretânicas de polímeros termoplásticos exibem mais baixas estabilidades térmica e oxidativa, resultando no aumento da concentração de grupos terminais NH2. A reatividade dessas misturas foi investigada através do torque durante o processo de mistura, da titulação potenciométrica dos grupos NH2 terminais e por microscopia eletrônica de varredura.Polyamide 6 (PA6 and polycarbonate (PC blends processed at 240 °C, during 10, 30 and 60 minutes produced a copolymer of PA6-PC. The high temperature and long processing time can cause modifications on the properties of these blends and degradation of the copolymer. It can also form isocyanate groups and subsequently CO2 and NH2 "end groups". The amount of PA6-PC copolymer formed during the blending process was found to increase when the PC content is increased. The thermoplastic urethanes normally exhibit smaller thermal and oxidative stability, resulting in an increase in the concentration of NH2 terminal groups. The reactivity of the blends was investigated by monitoring the torque during the blending, potentiometer titration of NH2 terminal groups and scanning electronic microscopy (SEM.

DARK MATTER HALOS IN GALAXIES AND GLOBULAR CLUSTER POPULATIONS

Energy Technology Data Exchange (ETDEWEB)

Hudson, Michael J.; Harris, Gretchen L. [Department of Physics and Astronomy, University of Waterloo, Waterloo, ON N2L 3G1 (Canada); Harris, William E., E-mail: mjhudson@uwaterloo.ca [Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1 (Canada)

2014-05-20

We combine a new, comprehensive database for globular cluster populations in all types of galaxies with a new calibration of galaxy halo masses based entirely on weak lensing. Correlating these two sets of data, we find that the mass ratio η ≡ M {sub GCS}/M {sub h} (total mass in globular clusters, divided by halo mass) is essentially constant at (η) ∼ 4 × 10{sup –5}, strongly confirming earlier suggestions in the literature. Globular clusters are the only known stellar population that formed in essentially direct proportion to host galaxy halo mass. The intrinsic scatter in η appears to be at most 0.2 dex; we argue that some of this scatter is due to differing degrees of tidal stripping of the globular cluster systems between central and satellite galaxies. We suggest that this correlation can be understood if most globular clusters form at very early stages in galaxy evolution, largely avoiding the feedback processes that inhibited the bulk of field-star formation in their host galaxies. The actual mean value of η also suggests that about one-fourth of the initial gas mass present in protogalaxies collected into giant molecular clouds large enough to form massive, dense star clusters. Finally, our calibration of (η) indicates that the halo masses of the Milky Way and M31 are (1.2 ± 0.5) × 10{sup 12} M {sub ☉} and (3.9 ± 1.8) × 10{sup 12} M {sub ☉}, respectively.

RETENTION OF STELLAR-MASS BLACK HOLES IN GLOBULAR CLUSTERS

International Nuclear Information System (INIS)

Morscher, Meagan; Umbreit, Stefan; Farr, Will M.; Rasio, Frederic A.

2013-01-01

Globular clusters should be born with significant numbers of stellar-mass black holes (BHs). It has been thought for two decades that very few of these BHs could be retained through the cluster lifetime. With masses ∼10 M ☉ , BHs are ∼20 times more massive than an average cluster star. They segregate into the cluster core, where they may eventually decouple from the remainder of the cluster. The small-N core then evaporates on a short timescale. This is the so-called Spitzer instability. Here we present the results of a full dynamical simulation of a globular cluster containing many stellar-mass BHs with a realistic mass spectrum. Our Monte Carlo simulation code includes detailed treatments of all relevant stellar evolution and dynamical processes. Our main finding is that old globular clusters could still contain many BHs at present. In our simulation, we find no evidence for the Spitzer instability. Instead, most of the BHs remain well mixed with the rest of the cluster, with only the innermost few tens of BHs segregating significantly. Over the 12 Gyr evolution, fewer than half of the BHs are dynamically ejected through strong binary interactions in the cluster core. The presence of BHs leads to long-term heating of the cluster, ultimately producing a core radius on the high end of the distribution for Milky Way globular clusters (and those of other galaxies). A crude extrapolation from our model suggests that the BH-BH merger rate from globular clusters could be comparable to the rate in the field.

Avaliação da competição intergenotipica em misturas de cultivares de soja Evaluation o f intergenotypic competition in soybean cultivars blends

Directory of Open Access Journals (Sweden)

Dilson Antonio Bisognin

1995-01-01

Full Text Available Para avaliar os efeitos da competição intergenotípica em misturas de cultivares de soja - Glycine max (L. Merrill - foi conduzido um experimento em Capão do Leão, RS, no ano agrícola de 1989/90. Os tratamentos foram os estandes puros de IAS 5, Ivorá, Bragg, BR 8 - Pelotas e Ivaí e as combinações de Bragg com os demais cultivares, nas proporções de 20, 35, 50, 65 e 80%. O delineamento experimental foi o látice parcialmente balanceado 5x5, com quatro repetições. A competição intergenotípica foi quantificada pela variação percentual = 100 (PM - PEP/ PEP, onde PM é a média do caráter em mistura e PEP é a média do caráter em estande puro. As misturas produziram, em média, 3,8% mais que a média dos componentes em estande puro. Duas misturas, IAS 5 + Bragg e BR 8-Pelotas + Bragg, proporcionaram acréscimos no rendimento em todas as proporções de misturas. Concluiu-se que a competição intergenotípica pode ser utilizada no melhoramento da soja, visando a obtenção de misturas com rendimento e desempenho superior. Respostas diferenciadas à competição intergenotípica foram observadas em diferentes misturas e proporções e, proporção e características contrastantes entre os cultivares como capacidade de ramificação, altura de planta, ciclo de maturação e período de florescimento devem ser consideradas para a formação de misturas superiores.Intergenotypic competition effects on soybean -Glycine max (L. Merrill - cultivar blends was evaluated in an experiment carried out along the 1989/90 crop season, in Capão do Leão county, RS. Five cultivars, IAS 5, Ivorá, Bragg, Ivaí and BR 8-Pelotas in pure stand and the blends of Bragg with every cultivar, in the proportions of 20, 35, 50, 65 and 80%, were alocated to a partially balanced 5 x 5 lattice design with four repetitions. Intergenotypic competition was quantified by percent vanation 1 (PM - PEP/PEP, where PM stands for the vanable mean in the blend and PEP

Infrared dust emission from globular clusters

International Nuclear Information System (INIS)

Angeletti, L.; Capuzzo-Dolcetta, R.; Giannone, P.; Blanco, A.; Bussoletti, E.

1982-01-01

The implications of the presence of a central cloud in the cores of globular clusters were investigated recently. A possible mechanism of confinement of dust in the central region of our cluster models was also explored. The grain temperature and infrared emission have now been computed for rather realistic grain compositions. The grain components were assumed to be graphite and/or silicates. The central clouds turned out to be roughly isothermal. The wavelengths of maximum emission came out to be larger than 20 μm in all studied cases. An application of the theoretical results to five globular clusters showed that the predictable infrared emission for 47 Tuc, M4 and M22 should be detectable by means of present instrumentation aboard flying platforms. (author)

Infrared dust emission from globular clusters

Energy Technology Data Exchange (ETDEWEB)

Angeletti, L; Capuzzo-Dolcetta, R; Giannone, P. (Rome Univ. (Italy). Osservatorio Astronomico); Blanco, A; Bussoletti, E [Lecce Univ. (Italy). Ist. di Fisica

1982-05-01

The implications of the presence of a central cloud in the cores of globular clusters were investigated recently. A possible mechanism of confinement of dust in the central region of our cluster models was also explored. The grain temperature and infrared emission have now been computed for rather realistic grain compositions. The grain components were assumed to be graphite and/or silicates. The central clouds turned out to be roughly isothermal. The wavelengths of maximum emission came out to be larger than 20 ..mu..m in all studied cases. An application of the theoretical results to five globular clusters showed that the predictable infrared emission for 47 Tuc, M4 and M22 should be detectable by means of present instrumentation aboard flying platforms.

Nanofibers made of globular proteins.

Science.gov (United States)

Dror, Yael; Ziv, Tamar; Makarov, Vadim; Wolf, Hila; Admon, Arie; Zussman, Eyal

2008-10-01

Strong nanofibers composed entirely of a model globular protein, namely, bovine serum albumin (BSA), were produced by electrospinning directly from a BSA solution without the use of chemical cross-linkers. Control of the spinnability and the mechanical properties of the produced nanofibers was achieved by manipulating the protein conformation, protein aggregation, and intra/intermolecular disulfide bonds exchange. In this manner, a low-viscosity globular protein solution could be modified into a polymer-like spinnable solution and easily spun into fibers whose mechanical properties were as good as those of natural fibers made of fibrous protein. We demonstrate here that newly formed disulfide bonds (intra/intermolecular) have a dominant role in both the formation of the nanofibers and in providing them with superior mechanical properties. Our approach to engineer proteins into biocompatible fibrous structures may be used in a wide range of biomedical applications such as suturing, wound dressing, and wound closure.

Integrated photometry of globular star clusters in the Vilnius system

International Nuclear Information System (INIS)

Zdanavichyus, K.V.

1983-01-01

Integrated colour indices in the Vilnius photometric system and newly determined colour excesses Esub(B-V) for 39 globular clusters are presented. It is shown that the coincidence of integrated spectral types are not a sufficient criterion for the identity of intrinsic colour indices of globular clusters. Relation of integrated colour indices with the slope of the giant branch S and with the horizontal branch morphological type D is investigated. Integrated colour indices of clusters with a blue horizontal branch show no correlation with either D or S. The increase of colour indices of the clusters of types D >= 4 correlates with the distribution of stars along the horizontal branch. Integrated photometry of globular star clusters in the Vilnius multicoloured photometric system permits to determine their colour excesses from some Q diagrams and normal colour index. Integral normal colour indexes and Q parameters for I globular star clusters of the Mironov group display small changes as compared to clusters of group 2. Colour indexes among star clusters having only red horizontal branches (D=7) change most considerably

Cold gelation of globular proteins

NARCIS (Netherlands)

Alting, A.C.

2003-01-01

Keywords : globular proteins, whey protein, ovalbumin, cold gelation, disulfide bonds, texture, gel hardnessProtein gelation in food products is important to obtain desirable sensory and textural properties. Cold gelation is a novel method to produce protein-based gels. It is a two step process in

Near infrared photometry of globular clusters

International Nuclear Information System (INIS)

Evans, T.L.; Menzies, J.W.

1977-01-01

Photographic photometry on the V, Isub(K) system has been obtained for giant stars in the metal-rich globular clusters NGC 5927, 6171, 6352, 6356, 6388, 6522, 6528, 6712 and 6723. Colour-magnitude diagrams are presented. These data, with earlier observations of NGC 104 (47 Tuc), yield new parameters to describe the giant branch. These are the colour of the red variables, represented by their mean colour (V - Isub(K)) 0 or by the colour (V - Isub(K))sub(BO) of the bluest red variable on the giant branch of a cluster, and ΔV' which is the magnitude difference between the horizontal branch and the highest point on the giant branch. The latter is independent of reddening, since the giant branch of the most metal-rich clusters passes through a maximum in the V, V - Isub(K) plane. These parameters are correlated with the metal content, deduced from integrated photometry: the red variables are redder and the giant branch fainter the higher the metal content. Comparison with theoretical evolutionary tracks suggests that the range in metal content of these clusters is at most a factor of 10, the most metal-rich clusters possibly approaching the solar value. The cluster giant branches and those of open clusters, groups and field stars of the old disk population are compared. The assumption that all the globular clusters have an absolute magnitude on the horizontal branch of Msub(v) = + 0.9, as found recently for 47 Tuc, gives good agreement between the magnitudes of giant stars in the most metal rich of the globular clusters and those of field stars deduced from statistical parallaxes and moving group parallaxes. The values of the parameters ΔV' and (V - Isub(k))sub(BO) also approach those in the moving groups. The globular clusters have a longer horizontal branch, however, and the subgiants are bluer even when the values of ) 7Fe/H{ appear to be the same. (author). )

On the evolution of globular clusters and the origin of galactic halo stars

International Nuclear Information System (INIS)

Surdin, V.G.

1978-01-01

Evolution of globular clusters of galactic halo is considered. It is shown that evolution of massive globular clusters with a greater degree of probability takes place under the effect of dynamic friction, which brings about the cluster fall on the center of galactic and their destruction by tidal forces. Evolution of small massive cluster takes place under the effect of dissipation. All the other reasons, causing the destruction of globular clusters (gravitational tidal forces, mutual cluster collision, outflow of gas from red gigant atmospheres, the change of the radius of the cluster orbit at the expense of the change of the galaxy mass inside the cluster orbit) play a secondary role. The whole mass of the stars lost by globular clusters does not exceed 10 7 M sun. It is concluded that the origin of the star population of galactic halo field can not be explained by destruction of already formed only astral globular clusters

Modular organization of proteins containing C1q-like globular domain.

Science.gov (United States)

Kishore, U; Reid, K B

1999-05-01

The first step in the activation of the classical pathway of complement cascade by immune complexes involves the binding of the six globular heads of C1q to the Fc regions of immunoglobulin G (IgG) or immunoglobulin M (IgM). The globular heads of C1q are located C-terminal to the six triple-helical stalks present in the molecule, each head is considered to be composed of the C-terminal halves (3 x 135 residues) of one A-, one B- and one C-chain. It is not known if the C-terminal globular regions, present in each of the three types of chains, are independently folded modules (with each chain having distinct binding properties towards immunoglobulins) or whether the different binding functions of C1q are dependent upon a globular structure which relies on contributions from all three chains. Recent reports of recombinant production and characterisation of soluble globular head regions of all the three chains indicate that the globular regions of C1q may adopt a modular organization, i.e., each globular head of C1q may be composed of three, structurally and functionally, independent domains, thus retaining multivalency in the form of a heterotrimer. Modules of the same type as the C1q C-terminal module are also found in a variety of noncomplement proteins that include the C-terminal regions of the human type VIII and type X collagens, precerebellin, the chipmunk hibernation proteins, the human endothelial cell protein, multimerin, the serum protein, Acrp-30 which is secreted from mouse adipocytes, and the sunfish inner-ear specific structural protein. The C1q molecule is the only one of these proteins for which, to date, a function has been ascribed to the module. The existence of a shared structural region between C1q and certain collagens may suggest an evolutionarily common ancestral precursor. Various structural and biochemical data suggest that these modules may be responsible for multimerisation through patches of aromatic residues within them.

Analytical Solution for Stellar Density in Globular Clusters MA Sharaf

Indian Academy of Sciences (India)

Introduction. A globular cluster is a spherical collection of stars that orbits a galactic core as a satellite. They are generally composed of hundreds of thousands of low-metal, old stars. The types of stars found in a globular cluster are similar to those in the bulge of a spiral galaxy but confined to a volume of only a few cubic ...

Thermal and pasting properties of cassava starch-dehydrated orange pulp blends Propriedades térmicas e de pasta de misturas de fécula de mandioca e polpa cítrica

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Magali Leonel

2011-06-01

Full Text Available Instant mixtures are easy to prepare and frequently present functional appeals. A quality parameter for instant mixtures is their rheological behavior. This study aimed at evaluating the effects of extrusion parameters on the pasting properties of cassava (Manihot esculenta L. starch and dehydrated orange (Citrus sinensis (L. Osbeck pulp mixtures. The variable parameters were moisture of mixtures (12.5 to 19%, barrel temperature (40 to 90ºC and screw rotation (170 to 266 rpm. The extruded mixtures did not show gelatinization enthalpy. Moisture had the greatest effect on paste properties. The initial pasting viscosity (before heating of RVA (Rapid visco analyzer is the most relevant parameter to instant mixtures. The highest cold viscosity values were obtained when mixtures were extruded under high moisture and high screw speed. High moisture (19.5%, intermediate temperature (65ºC and screw speed (218 rpm led to extruded mixtures production with low component degradation.Misturas instantâneas apresentam-se como produtos de fácil preparo e muitas vezes com apelos funcionais. Um parâmetro de qualidade nestas misturas é o comportamento reológico. Avaliou-se o efeito de parâmetros de extrusão sobre as propriedades de pasta de misturas de fécula de mandioca (Manihot esculenta L. e polpa de laranja (Citrus sinensis (L. Osbeck desidratada. A umidade das misturas (12.5 a 19%, a temperatura de extrusão (40 a 90ºC e a rotação da rosca (170 a 266 rpm foram considerados parâmetros variáveis. As misturas extrusadas não apresentaram entalpia de gelatinização. A umidade foi o fator de maior efeito sobre as propriedades de pasta. A viscosidade inicial (antes do aquecimento no RVA (Rapid visco analyzer é um dos parâmetros mais importantes para misturas instantâneas. Nas condições de elevada umidade e rotação da rosca são observadas as maiores viscosidades a frio. Condições de elevada umidade das misturas (19,5%, temperatura (65ºC e

A New Globular Cluster in the Area of VVVX

Science.gov (United States)

Bica, E.; Minniti, D.; Bonatto, C.; Hempel, M.

2018-06-01

We communicate the discovery of a new globular cluster in the Galaxy that was first detected on WISE/2MASS images and is now confirmed with VVVX photometry. It is a Palomar-like cluster projected at ℓ = 359.15°, b = 5.73°, and may be related to the bulge. We derive an absolute magnitude of MV ≈ -3.3, thus being an underluminous globular cluster. Our analyses provide a reddening of E(B - V) = 1.08 ± 0.18 and a distance to the Sun d⊙ = 6.3 ± 1 kpc, which implies a current position in the bulge volume. The estimated metallicity is [Fe/H] = -1.5 ± 0.25. It adds to the recently discovered faint globular cluster (Minniti 22) and candidates found with VVV, building up expectations of ≈50 globular clusters yet to be discovered in the bulge. We also communicate the discovery of an old open cluster in the same VVVX tile as the globular cluster. The VVVX photometry provided E(B - V) = 0.62 ± 0.1, d⊙ = 7.6 ± 1 kpc, and an age of 1.5 ± 0.3 Gyr. With a height from the plane of ≈0.8 kpc, it adds to nine Gyr-class clusters recently discovered within 0.8 ⩽ Z ⩽ 2.2 kpc, as recently probed in the single VVV tile b201. We suggest that these findings may be disclosing the thick disk at the bulge, which so far has no open cluster counterpart, and hardly any individual star. Thus, the VVV and VVVX surveys are opening new windows for follow-up studies, to employ present and future generations of large aperture telescopes.

Systematic main sequence photometry of globular cluster stars for age determination

International Nuclear Information System (INIS)

Alcaino, G.; Liller, W.

1984-01-01

The individual photometric study of the coeval stars in globular clusters presents one of the best observational tests of the stellar evolution theory. Our own globular cluster system provides fundamental clues to the dynamical and chemical evolutionary history of the galaxy, and the study of their ages give a lower limit to the age of the galaxy as well as to that of the universe. The authors have undertaken a systematic research program, and discuss the ages deduced by fitting main sequence photometry to theoretical isochrones of six galactic globular clusters: M4, M22, M30, NGC 288, NGC 3201 and NGC 6397. (Auth.)

EVIDENCE FOR AN ACCRETION ORIGIN FOR THE OUTER HALO GLOBULAR CLUSTER SYSTEM OF M31

International Nuclear Information System (INIS)

Mackey, A. D.; Huxor, A. P.; Ferguson, A. M. N.; Irwin, M. J.; Chapman, S. C.; Tanvir, N. R.; McConnachie, A. W.; Ibata, R. A.; Lewis, G. F.

2010-01-01

We use a sample of newly discovered globular clusters from the Pan-Andromeda Archaeological Survey (PAndAS) in combination with previously cataloged objects to map the spatial distribution of globular clusters in the M31 halo. At projected radii beyond ∼30 kpc, where large coherent stellar streams are readily distinguished in the field, there is a striking correlation between these features and the positions of the globular clusters. Adopting a simple Monte Carlo approach, we test the significance of this association by computing the probability that it could be due to the chance alignment of globular clusters smoothly distributed in the M31 halo. We find that the likelihood of this possibility is low, below 1%, and conclude that the observed spatial coincidence between globular clusters and multiple tidal debris streams in the outer halo of M31 reflects a genuine physical association. Our results imply that the majority of the remote globular cluster system of M31 has been assembled as a consequence of the accretion of cluster-bearing satellite galaxies. This constitutes the most direct evidence to date that the outer halo globular cluster populations in some galaxies are largely accreted.

Seeing deconvolution of globular clusters in M31

International Nuclear Information System (INIS)

Bendinelli, O.; Zavatti, F.; Parmeggiani, G.; Djorgovski, S.

1990-01-01

The morphology of six M31 globular clusters is examined using seeing-deconvolved CCD images. The deconvolution techniques developed by Bendinelli (1989) are reviewed and applied to the M31 globular clusters to demonstrate the methodology. It is found that the effective resolution limit of the method is about 0.1-0.3 arcsec for CCD images obtained in FWHM = 1 arcsec seeing, and sampling of 0.3 arcsec/pixel. Also, the robustness of the method is discussed. The implications of the technique for future studies using data from the Hubble Space Telescope are considered. 68 refs

Caracterização físico-química de misturas de óleos vegetais para fins alimentares

Directory of Open Access Journals (Sweden)

Katcilanya Menezes Almeida

2013-05-01

Full Text Available Objetivou-se, com este trabalho, a elaboração e caracterização de misturas especiais de óleos vegetais para fins alimentícios, com base nos óleos de amendoim, gergelim, maracujá e soja. Os óleos de amendoim e gergelim foram extraídos de sementes das cultivares BRS-Havana e BRS-Seda, respectivamente, cedidas pela Embrapa Algodão enquanto o óleo de maracujá foi adquirido no comércio de São Paulo e o de soja no de Campina Grande. As misturas foram elaboradas com base em uma matriz de planejamento experimental e, em seguida, submetidas aos ensaios físico-químicas (umidade, índice de acidez, índice de iodo, índice de refração, densidade e viscosidade segundo a metodologia do IAL (2008. Os resultados foram submetidos à análise de variância (ANOVA por delineamento inteiramente casualizado com 17 tratamentos e 6 variáveis pelo software ASSISTAT versão 7.6 beta. Todas as misturas diferiram estatisticamente entre si a nível de 1% pelo teste de Tukey e apresentaram-se aptas para fins alimentares, com influência da significante quantidade de ácidos graxos insaturados em todas as medidas físico-quimicas. Os óleos de maracujá e soja são quimicamente semelhantes.

Observations of CO and OI in stars in globular clusters

International Nuclear Information System (INIS)

Wallerstein, G.; Pilachowski, C.

1978-01-01

Since studies at classification dispersion and early analyses of high dispersion spectra have yielded little quantitative data on the abundances of C, N, and O in globular clusters the authors have been endeavoring to establish their abundances in stars in several clusters. The problem has been approached in two ways, by observing the 2.3 micron CO bands and the 6300 A [OI] line in individual stars in globular clusters. (Auth.)

The gamma-ray pulsar population of globular clusters: implications for the GeV excess

Energy Technology Data Exchange (ETDEWEB)

Hooper, Dan [Fermi National Accelerator Laboratory, Center for Particle Astrophysics, Batavia, IL 60510 (United States); Linden, Tim, E-mail: dhooper@fnal.gov, E-mail: linden.70@osu.edu [Ohio State University, Center for Cosmology and AstroParticle Physcis (CCAPP), Columbus, OH 43210 (United States)

2016-08-01

It has been suggested that the GeV excess, observed from the region surrounding the Galactic Center, might originate from a population of millisecond pulsars that formed in globular clusters. With this in mind, we employ the publicly available Fermi data to study the gamma-ray emission from 157 globular clusters, identifying a statistically significant signal from 25 of these sources (ten of which are not found in existing gamma-ray catalogs). We combine these observations with the predicted pulsar formation rate based on the stellar encounter rate of each globular cluster to constrain the gamma-ray luminosity function of millisecond pulsars in the Milky Way's globular cluster system. We find that this pulsar population exhibits a luminosity function that is quite similar to those millisecond pulsars observed in the field of the Milky Way (i.e. the thick disk). After pulsars are expelled from a globular cluster, however, they continue to lose rotational kinetic energy and become less luminous, causing their luminosity function to depart from the steady-state distribution. Using this luminosity function and a model for the globular cluster disruption rate, we show that millisecond pulsars born in globular clusters can account for only a few percent or less of the observed GeV excess. Among other challenges, scenarios in which the entire GeV excess is generated from such pulsars are in conflict with the observed mass of the Milky Way's Central Stellar Cluster.

A Science Portal and Archive for Extragalactic Globular Cluster Systems Data

Science.gov (United States)

Young, Michael; Rhode, Katherine L.; Gopu, Arvind

2015-01-01

For several years we have been carrying out a wide-field imaging survey of the globular cluster populations of a sample of giant spiral, S0, and elliptical galaxies with distances of ~10-30 Mpc. We use mosaic CCD cameras on the WIYN 3.5-m and Kitt Peak 4-m telescopes to acquire deep BVR imaging of each galaxy and then analyze the data to derive global properties of the globular cluster system. In addition to measuring the total numbers, specific frequencies, spatial distributions, and color distributions for the globular cluster populations, we have produced deep, high-quality images and lists of tens to thousands of globular cluster candidates for the ~40 galaxies included in the survey.With the survey nearing completion, we have been exploring how to efficiently disseminate not only the overall results, but also all of the relevant data products, to the astronomical community. Here we present our solution: a scientific portal and archive for extragalactic globular cluster systems data. With a modern and intuitive web interface built on the same framework as the WIYN One Degree Imager Portal, Pipeline, and Archive (ODI-PPA), our system will provide public access to the survey results and the final stacked mosaic images of the target galaxies. In addition, the astrometric and photometric data for thousands of identified globular cluster candidates, as well as for all point sources detected in each field, will be indexed and searchable. Where available, spectroscopic follow-up data will be paired with the candidates. Advanced imaging tools will enable users to overlay the cluster candidates and other sources on the mosaic images within the web interface, while metadata charting tools will allow users to rapidly and seamlessly plot the survey results for each galaxy and the data for hundreds of thousands of individual sources. Finally, we will appeal to other researchers with similar data products and work toward making our portal a central repository for data

Obtenção de cermet por tecnologia do pó a partir da utilização da cinza leve proveniente da queima do carvão mineral em termoelétrica

OpenAIRE

Andréia Brogni

2013-01-01

Este trabalho busca produzir cermet (Cinza-Fe) pela tecnologia do pó utilizando cinza leve produzida com a queima do carvão mineral em termoelétrica para uma possível utilização e aplicação na usinagem. Esse estudo tem como objetivo específico caracterizar e analisar as propriedades mecânicas e metalúrgicas das amostras obtidas a partir das misturas. Utilizouse o ferro como componente da mistura em função do baixo custo e vasta disponibilidade. Após a obtenção da cinza leve, determinou-se o t...

Two stellar-mass black holes in the globular cluster M22.

Science.gov (United States)

Strader, Jay; Chomiuk, Laura; Maccarone, Thomas J; Miller-Jones, James C A; Seth, Anil C

2012-10-04

Hundreds of stellar-mass black holes probably form in a typical globular star cluster, with all but one predicted to be ejected through dynamical interactions. Some observational support for this idea is provided by the lack of X-ray-emitting binary stars comprising one black hole and one other star ('black-hole/X-ray binaries') in Milky Way globular clusters, even though many neutron-star/X-ray binaries are known. Although a few black holes have been seen in globular clusters around other galaxies, the masses of these cannot be determined, and some may be intermediate-mass black holes that form through exotic mechanisms. Here we report the presence of two flat-spectrum radio sources in the Milky Way globular cluster M22, and we argue that these objects are black holes of stellar mass (each ∼10-20 times more massive than the Sun) that are accreting matter. We find a high ratio of radio-to-X-ray flux for these black holes, consistent with the larger predicted masses of black holes in globular clusters compared to those outside. The identification of two black holes in one cluster shows that ejection of black holes is not as efficient as predicted by most models, and we argue that M22 may contain a total population of ∼5-100 black holes. The large core radius of M22 could arise from heating produced by the black holes.

Spectroscopic confirmation of the first symbiotic star in a globular cluster

Science.gov (United States)

Zurek, David

2013-10-01

We have recently discovered an 18-minute period in the ultraviolet of a star in the globular cluster NGC 1851. In the redder optical bands, this star is red and bright, while it shows a clear UV excess relative to other stars at similar positions in the HR diagram. The system is most likely a symbiotic binary, composed of a cool evolved star and a white dwarf, with an 18 minute spin period, accreting the cool star's wind. The binary would be the first such object ever found in a globular cluster, and only the third in the Galaxy where the white dwarf spin period is measured. The only viable alternatives are that the two components are a chance superposition - something with a nontrivial chance of happening in a globular cluster core. In such a case, the 18 minute period would most likely be the spin period of a magnetic white dwarf in an intermediate polar cataclysmic variable {this would be the first confirmed magnetic CV in a globular cluster}, or the orbital period of a double-degenerate AM CVn binary. Each of these three possibilities show unique {and very different} emission line spectra in the blue wavelength range. Two orbits of HST with STIS/G430L will produce a spectrum of sufficient signal-to-noise to distinguish between these 3 scenarios. The result will be an important constraint on N-body models of globular clusters.

The Blue Hook Populations of Massive Globular Clusters

Science.gov (United States)

Brown, Thomas

2006-07-01

Blue hook stars are a class of hot { 35,000 K} subluminous horizontal branch stars that have been recently discovered using HST ultraviolet images of the globular clusters omega Cen and NGC 2808. These stars occupy a region of the HR diagram that is unexplained by canonical stellar evolution theory. Using new theoretical evolutionary and atmospheric models, we have shown that the blue hook stars are very likely the progeny of stars that undergo extensive internal mixing during a late helium core flash on the white dwarf cooling curve. This "flash mixing" produces an enormous enhancement of the surface helium and carbon abundances, which suppresses the flux in the far ultraviolet. Although flash mixing is more likely to occur in stars that are born with high helium abundances, a high helium abundance, by itself, does not explain the presence of a blue hook population - flash mixing of the envelope is required. We propose ACS ultraviolet {SBC/F150LP and HRC/F250W} observations of the five additional globular clusters for which the presence of blue hook stars is suspected from longer wavelength observations. Like omega Cen and NGC 2808, these five targets are also among the most massive globular clusters, because less massive clusters show no evidence for blue hook stars. Because our targets span 1.5 dex in metallicity, we will be able to test our prediction that flash-mixing should be less drastic in metal-rich blue hook stars. In addition, our observations will test the hypothesis that blue hook stars only form in globular clusters massive enough to retain the helium-enriched ejecta from the first stellar generation. If this hypothesis is correct, then our observations will yield important constraints on the chemical evolution and early formation history in globular clusters, as well as the role of helium self-enrichment in producing blue horizontal branch morphologies and multiple main sequence turnoffs. Finally, our observations will provide new insight into the

Evolution of redback radio pulsars in globular clusters

Science.gov (United States)

Benvenuto, O. G.; De Vito, M. A.; Horvath, J. E.

2017-02-01

Context. We study the evolution of close binary systems composed of a normal, intermediate mass star and a neutron star considering a chemical composition typical of that present in globular clusters (Z = 0.001). Aims: We look for similarities and differences with respect to solar composition donor stars, which we have extensively studied in the past. As a definite example, we perform an application on one of the redbacks located in a globular cluster. Methods: We performed a detailed grid of models in order to find systems that represent the so-called redback binary radio pulsar systems with donor star masses between 0.6 and 2.0 solar masses and orbital periods in the range 0.2-0.9 d. Results: We find that the evolution of these binary systems is rather similar to those corresponding to solar composition objects, allowing us to account for the occurrence of redbacks in globular clusters, as the main physical ingredient is the irradiation feedback. Redback systems are in the quasi-RLOF state, that is, almost filling their corresponding Roche lobe. During the irradiation cycle the system alternates between semi-detached and detached states. While detached the system appears as a binary millisecond pulsar, called a redback. Circumstellar material, as seen in redbacks, is left behind after the previous semi-detached phase. Conclusions: The evolution of binary radio pulsar systems considering irradiation successfully accounts for, and provides a way for, the occurrence of redback pulsars in low-metallicity environments such as globular clusters. This is the case despite possible effects of the low metal content of the donor star that could drive systems away from redback configuration.

The Most Massive Star Clusters: Supermassive Globular Clusters or Dwarf Galaxy Nuclei?

Science.gov (United States)

Harris, William

2004-07-01

Evidence is mounting that the most massive globular clusters, such as Omega Centauri and M31-G1, may be related to the recently discovered "Ultra-Compact Dwarfs" and the dense nuclei of dE, N galaxies. However, no systematic imaging investigation of these supermassive globular clusters - at the level of Omega Cen and beyond - has been done, and we do not know what fraction of them might bear the signatures {such as large effective radii or tidal tails} of having originated as dE nuclei. We propose to use the ACS/WFC to obtain deep images of 18 such clusters in NGC 5128 and M31, the two nearest rich globular cluster systems. These globulars are the richest star clusters that can be found in nature, the biggest of them reaching 10^7 Solar masses, and they are likely to represent the results of star formation under the densest and most extreme conditions known. Using the profiles of the clusters including their faint outer envelopes, we will carry out state-of-the-art dynamical modelling of their structures, and look for any clear evidence which would indicate that they are associated with stripped satellites. This study will build on our previous work with STIS and WFPC2 imaging designed to study the 'Fundamental Plane' of globular clusters. When our new work is combined with Archival WFPC2, STIS, and ACS material, we will also be able to construct the definitive mapping of the Fundamental Plane of globular clusters at its uppermost mass range, and confirm whether or not the UCD and dE, N objects occupy a different structural parameter space.

An observational study of disk-population globular clusters

International Nuclear Information System (INIS)

Armandroff, T.E.

1988-01-01

Integrated-light spectroscopy was obtained for twenty-seven globular clusters at the Ca II infrared triplet. Line strengths and radial velocities were measured from the spectra. For the well-studied clusters in the sample, the strength of the CA II lines is very well correlated with previous metallicity estimates obtained using a variety of techniques. The greatly reduced effect of interstellar extinction at these wavelengths compared to the blue region of the spectrum has permitted observations of some of the most heavily reddened clusters in the Galaxy. For several such clusters, the Ca II triplet metallicities are in poor agreement with metallicity estimates from infrared photometry by Malkan. Color-magnitude diagrams were constructed for six previously unstudied metal-rich globular clusters and for the well-studied cluster 47 Tuc. The V magnitudes of the horizontal branch stars in the six clusters are in poor agreement with previous estimates based on secondary methods. The horizontal branch morphologies and reddenings of the program clusters were also determined. Using the improved set of metallicities, radial velocities, and distance moduli, the spatial distribution, kinematics, and metallicity distribution of the Galactic globulars were analyzed. The revised data supports Zinn's conclusion that the metal-rich clusters form a highly flattened, rapidly rotating disk system, while the metal-poor clusters make up the familiar, spherically distributed, slowly rotating halo population. The scale height, metallicity distribution, and kinematics of the metal-rich globulars are in good agreement with those of the stellar thick disk. Luminosity functions were constructed, and no significant difference is found between disk and halo samples. Metallicity gradients seem to be present in the disk cluster system. The implications of these results for the formation and evol

Rates of collapse and evaporation of globular clusters

Science.gov (United States)

Hut, Piet; Djorgovski, S.

1992-01-01

Observational estimates of the dynamical relaxation times of Galactic globular clusters are used here to estimate the present rate at which core collapse and evaporation are occurring in them. A core collapse rate of 2 +/- 1 per Gyr is found, which for a Galactic age of about 12 Gyr agrees well with the fact that 27 clusters have surface brightness profiles with the morphology expected for the postcollapse phase. A destruction and evaporation rate of 5 +/- 3 per Gyr is found, suggesting that a significant fraction of the Galaxy's original complement of globular clusters have perished through the combined effects of mechanisms such as relaxation-driven evaporation and shocking due to interaction with the Galactic disk and bulge.

Effect of radiation pressure in the cores of globular clusters

Energy Technology Data Exchange (ETDEWEB)

Angeletti, L; Capuzzo-Dolcetta, R; Giannone

1981-10-01

The possible effects of a presence of a dust cloud in the cores of globular clusters was investigated. Two cluster models were considered together with various models of clouds. The problem of radiation transfer was solved under some simplifying assumptions. Owing to a differential absorption of the star light in the cloud, radiation pressure turned out be inward-directed in some cloud models. This fact may lead to a confinement of some dust in the central regions of globular clusters.

Globular clusters as a source of X-ray emission from the neighbourhood of M87

International Nuclear Information System (INIS)

Fabian, A.C.; Pringle, J.E.; Rees, M.J.

1976-01-01

It is stated that the X-ray emission from globular clusters may be attributable to accretion on to compact objects, the accreting material being supplied from binary companions, or gas trapped in the potential well of the cluster. Counts of objects in the vicinity of the M87 have revealed that it has an extensive halo of globular clusters, the number of which may exceed 10,000 within a radius of 23 arc min. Most of these clusters may be explicable as a population effect, and the similarity of their optical properties to those of cluster in our own Galaxy suggests that they may also contain X-ray sources. The brighter globular clusters in M87 may, however, be substantially more X-ray luminous, and there may be proportionally more gas available in globular clusters in M87 compared with our Galaxy. The average X-ray luminosity of individual globular clusters may be of the order of 10 38 erg/sec., which raises the possibility that the integrated globular cluster emission may account for a substantial fraction of the X-ray emission observed from the region of M87. In support of this it is noted that the extended X-ray emission from the Virgo cluster is centered on M87, which lies approximately 45 arc min from the cluster centroid, and it is expected that the general X-ray emission from the globular cluster will appear to be smoothly and symmetrically distributed about M87 at moderate spatial resolution. A similar situation may apply to the elliptical galaxy NGC 3311 in Abell 1060 which, as a cluster, has been suggested as the identification for the X-ray source 3 U 1044-40, and it seems possible that that galaxy is surrounded by a similar globular cluster population to that of M87. (U.K.)

Chemical Abundances of Giants in Globular Clusters

Science.gov (United States)

Gratton, Raffaele G.; Bragaglia, Angela; Carretta, Eugenio; D'Orazi, Valentina; Lucatello, Sara

A large fraction of stars form in clusters. According to a widespread paradigma, stellar clusters are prototypes of single stellar populations. According to this concept, they formed on a very short time scale, and all their stars share the same chemical composition. Recently it has been understood that massive stellar clusters (the globular clusters) rather host various stellar populations, characterized by different chemical composition: these stellar populations have also slightly different ages, stars of the second generations being formed from the ejecta of part of those of an earlier one. Furthermore, it is becoming clear that the efficiency of the process is quite low: many more stars formed within this process than currently present in the clusters. This implies that a significant, perhaps even dominant fraction of the ancient population of galaxies formed within the episodes that lead to formation the globular clusters.

The evoluation of the galactic globular clusters; I Metal abundance calibrations

International Nuclear Information System (INIS)

Lee, S.W.; Park, N.K.

1984-01-01

Five different calibrations of metal abundances of globular clusters are examined and these are compared with metallicity ranking parameters such as (Sp)sub(c), , Q39 and IR-indices. Except for the calibration *(Fe/H*)sub(H) by the high dispersion echelle analysis, the other calibration scales are correlated with the morphological parameters of red giant branch. In the *(Fe/H*)sub(Hsup(-))scale, the clusters later than approx.F8 have nearly a constant metal abundance, *(Fe/H*)sub(H)approx.-1.05, regardless of morphological characteristics of horizontal branch and red giant branch. By the two fundamental calibration scales of *(Fe/H*)sub(L) (derived by the low dispersion analysis), and *(Fe/H*)sub(delta S) (derived by the spectral analysis of RR Lyrae stars), the globular clusters are divided into the halo clusters with *(Fe/H*)<-1.0 and the disk clusters confined within the galactocentric distance rsub(G)=10 kpc and galactic plane distance absolute z=3 kpc. In this case the abundance gradient is given by d*(Fe/H*)/drsub(G)approx.-0.05kpcsup(-1) and d*(Fe/H*)/d absolute z approx. -0.08 kpcsup(-1) within rsub(G)=20 kpc and absolute z=10 kpc, respectively. According to these characteristics of the spatial distribution of globular clusters, the chemical evolution of the galactic globular clusters can be accounted for by the two-zone (disk-halo) slow collapse model when the *(Fe/H*)sub(Lsup(-)) or *(Fe/H*)sub(DELTA Ssup(-))scale is applied. In the case of *(Fe/H*)sub(Hsup(-))scale, the one-zone fast collapse model is preferred for the evolution of globular clusters. (Author)

A catalogue of masses, structural parameters and velocity dispersion profiles of 112 Milky Way globular clusters

Science.gov (United States)

Baumgardt, H.; Hilker, M.

2018-05-01

We have determined masses, stellar mass functions and structural parameters of 112 Milky Way globular clusters by fitting a large set of N-body simulations to their velocity dispersion and surface density profiles. The velocity dispersion profiles were calculated based on a combination of more than 15,000 high-precision radial velocities which we derived from archival ESO/VLT and Keck spectra together with ˜20, 000 published radial velocities from the literature. Our fits also include the stellar mass functions of the globular clusters, which are available for 47 clusters in our sample, allowing us to self-consistently take the effects of mass segregation and ongoing cluster dissolution into account. We confirm the strong correlation between the global mass functions of globular clusters and their relaxation times recently found by Sollima & Baumgardt (2017). We also find a correlation of the escape velocity from the centre of a globular cluster and the fraction of first generation stars (FG) in the cluster recently derived for 57 globular clusters by Milone et al. (2017), but no correlation between the FG star fraction and the global mass function of a globular cluster. This could indicate that the ability of a globular cluster to keep the wind ejecta from the polluting star(s) is the crucial parameter determining the presence and fraction of second generation stars and not its later dynamical mass loss.

Binary Black Hole Mergers from Globular Clusters: Implications for Advanced LIGO.

Science.gov (United States)

Rodriguez, Carl L; Morscher, Meagan; Pattabiraman, Bharath; Chatterjee, Sourav; Haster, Carl-Johan; Rasio, Frederic A

2015-07-31

The predicted rate of binary black hole mergers from galactic fields can vary over several orders of magnitude and is extremely sensitive to the assumptions of stellar evolution. But in dense stellar environments such as globular clusters, binary black holes form by well-understood gravitational interactions. In this Letter, we study the formation of black hole binaries in an extensive collection of realistic globular cluster models. By comparing these models to observed Milky Way and extragalactic globular clusters, we find that the mergers of dynamically formed binaries could be detected at a rate of ∼100 per year, potentially dominating the binary black hole merger rate. We also find that a majority of cluster-formed binaries are more massive than their field-formed counterparts, suggesting that Advanced LIGO could identify certain binaries as originating from dense stellar environments.

Misturas de herbicidas para o controle de plantas daninhas do gênero Commelina Herbicide mixtures to control weeds of the genus Commelina

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C.P. Ronchi

2002-08-01

Full Text Available Este trabalho teve como objetivo avaliar a eficiência de misturas de herbicidas no controle de duas espécies de trapoeraba, Commelina diffusa e Commelina benghalensis. Para isso, segmentos de caule dessas espécies foram transplantados em vasos contendo 12 L de substrato. Após 120 dias, foram aplicados os seguintes tratamentos: carfentrazone-ethyl (30 g ha¹ em mistura com glyphosate (720 g ha-1 e/ou glyphosate potássico (720 g ha-1; glyphosate (720 g ha-1 em mistura com flumioxazin (60 g ha-1 e/ou 2,4-D (670 g ha-1 e/ou metsulfuron methyl (4 g ha-1; oxyfluorfen em mistura com sulfentrazone (480 + 375 g ha¹; aplicações seqüenciais, com intervalo de 21 dias, de [(paraquat + diuron / (carfentrazone-ethyl + glyphosate] [(200+400/(30+720] e de [(paraquat + diuron / (paraquat + diuron] [(200+400/(200+400]; e testemunha sem aplicação de herbicida. Cada espécie constituiu um experimento, sendo ambos conduzidos no delineamento em blocos casualizados, com quatro repetições. Foram feitas avaliações de controle das trapoerabas e da biomassa fresca da parte aérea. Os tratamentos mais eficientes no controle das trapoerabas foram as aplicações seqüenciais, com intervalo de 21 dias, de (paraquat + diuron / (carfentrazone-ethyl + glyphosate e de (paraquat + diuron / (paraquat + diuron, seguidas das misturas em tanque de 2,4-D + glyphosate e de carfentrazone-ethyl + glyphosate e/ou glyphosate potássico.This research was conducted to evaluate the efficiency of herbicide mixtures in the control of two dayflower species, Commelina diffusa and Commelina benghalensis. These species were grown from stem segments in 12 L pots during 120 days. Subsequently, a randomized complete block design with four replicates was performed for each species. The treatments were carfentrazone-ethyl combined to either glyphosate or glyphosate-potassium salt (30 + 720 g ha-1; glyphosate (720 g ha-1 combined to flumioxazin (60 g ha-1, or 2.4-D (670 g ha-1 or

On tidal radius determination for a globular cluster

International Nuclear Information System (INIS)

Ninkovic, S.

1985-01-01

A tidal radius determination for a globular cluster based on its density minimum, which is caused by the galactic tidal forces and derivable from a model of the Galaxy, is proposed. Results obtained on the basis of the Schmidt model for two clusters are in a satisfactory agreement with those obtained earlier by means of other methods. A mass determination for the clusters through the tidal radius, when the latter one is identified with the cluster perigalactic distance, yields unusually large mass values. Probably, the tidal radius should be identified with the instantaneous galactocentric distance. Use of models more recent than the Schmidt one indicates that a globular cluster may contain a significant portion of an invisible interstellar matter. (author)

Globular Cluster Candidates for Hosting a Central Black Hole

Science.gov (United States)

Noyola, Eva

2009-07-01

We are continuing our study of the dynamical properties of globular clusters and we propose to obtain surface brightness profiles for high concentration clusters. Our results to date show that the distribution of central surface brightness slopes do not conform to standard models. This has important implications for how they form and evolve, and suggest the possible presence of central intermediate-mass black holes. From our previous archival proposals {AR-9542 and AR-10315}, we find that many high concentration globular clusters do not have flat cores or steep central cusps, instead they show weak cusps. Numerical simulations suggest that clusters with weak cusps may harbor intermediate-mass black holes and we have one confirmation of this connection with omega Centauri. This cluster shows a shallow cusp in its surface brightness profile, while kinematical measurements suggest the presence of a black hole in its center. Our goal is to extend these studies to a sample containing 85% of the Galactic globular clusters with concentrations higher than 1.7 and look for objects departing from isothermal behavior. The ACS globular cluster survey {GO-10775} provides enough objects to have an excellent coverage of a wide range of galactic clusters, but it contains only a couple of the ones with high concentration. The proposed sample consists of clusters whose light profile can only be adequately measured from space-based imaging. This would take us close to completeness for the high concentration cases and therefore provide a more complete list of candidates for containing a central black hole. The dataset will also be combined with our existing kinematic measurements and enhanced with future kinematic studies to perform detailed dynamical modeling.

Desenvolvimento de nanocompósitos a partir de um elastômero termoplástico

OpenAIRE

Hugo Mauricio Tiggemann

2012-01-01

Elastômeros termoplásticos baseados em misturas SEBS/PP/Óleo emcontram aplicação em diversas áreas. Visando a obtenção de melhores propriedades mecânicas e boa processabilidade, foram preparados nanocompósitos utilizando um TPE à base de SEBS/PP/Óleo juntamente com 2, 5 e 7 phr de três argilas organicamente modificadas e wollastonita. Os nanocompósitos foram preparados através da intercalação no estado fundido em câmara de mistura e analisados através de suas propriedades mecânicas, reológica...

Sobrevivência de Bradyrhizobium e Azorhizobium em misturas de solo contaminadas com metais pesados

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A. Matsuda

2002-03-01

Full Text Available Estudos foram realizados no Departamento de Ciência do Solo da Universidade Federal de Lavras (MG, no período de novembro/1999 a janeiro/2000, com o objetivo de avaliar a sobrevivência de estirpe e isolados de rizóbio em solo contaminado com metais pesados e verificar a relação entre tolerância do rizóbio a metais pesados em meio de cultura e sua sobrevivência em solo contaminado. Foram utilizados os dois microrganismos mais tolerantes [BR-4406 (estirpe recomendada para Enterolobium spp. e UFLA-01-457 (isolado de solo contaminado, ambos pertencentes ao gênero Bradyrhizobium ] e os dois mais sensíveis (UFLA-01-486 e UFLA-01-510, isolados de solo contaminado, pertencentes ao gênero Azorhizobium , todos selecionados de um grupo de 60estirpes/isolados em estudos prévios deste laboratório, em meio de cultura suplementado com metais pesados.Empregaram-se misturas de um Latossolo Vermelho-Escuro (LE que continham 0, 15 e 45% (v/v de um Latossolo Vermelho-Amarelo plíntico contaminado com Zn, Cd, Pb e Cu. As misturas de solo contaminado foram inoculadas com 20mL de cultura em YM na fase log das estirpes mencionadas, as quais foram testadas separadamente com três repetições. A avaliação do número de células viáveis no solo, realizada aos 0, 7, 14, 21 e 28dias de incubação, pelo método das diluições sucessivas e inoculação em placas com meio YMA, revelou comportamento diferenciado entre os organismos estudados. O número médio de células que sobreviveram ao final de 28 dias de incubação foi de (em UFCg-1de solo: 10(10,36, 10(10,29 e 10(9,70, para Bradyrhizobium, e 10(9,36, 10(7,54 e 0, para Azorhizobium em misturas de 0, 15 e 45% de solo contaminado, respectivamente. Portanto, houve maior sobrevivência de Bradyrhizobium do que de Azorhizobium , indicando maior tolerância a metais pesados do primeiro gênero.Como Bradyrhizobium foi também mais tolerante "in vitro", os resultados indicam haver relação entre o

Produtos extrusados expandidos de misturas de canjiquinha e soja para uso como petiscos.

OpenAIRE

FERNANDES, M. dos S.; WANG, S.; ASCHERI, J.L.R.; OLIVEIRA, M.F. de; COSTA, S.A.J.

2003-01-01

O objetivo deste trabalho foi estudar o efeito da temperatura de barril (TB) do extrusor no índice de expansão (IE) e no índice de solubilidade em água (ISA) dos produtos extrusados expandidos de misturas de canjiquinha e soja (80:20 e 70:30), e verificar suas características sensoriais, quando aromatizado para uso como petiscos. Foi usado o extrusor Brabender de dupla-rosca, com velocidade de alimentação constante de 20,8 kg/h, velocidade da rotação de parafuso de 100 rpm e diâmetro de matri...

HUBBLE PINPOINTS WHITE DWARFS IN GLOBULAR CLUSTER

Science.gov (United States)

2002-01-01

Peering deep inside a cluster of several hundred thousand stars, NASA's Hubble Space Telescope uncovered the oldest burned-out stars in our Milky Way Galaxy. Located in the globular cluster M4, these small, dying stars - called white dwarfs - are giving astronomers a fresh reading on one of the biggest questions in astronomy: How old is the universe? The ancient white dwarfs in M4 are about 12 to 13 billion years old. After accounting for the time it took the cluster to form after the big bang, astronomers found that the age of the white dwarfs agrees with previous estimates for the universe's age. In the top panel, a ground-based observatory snapped a panoramic view of the entire cluster, which contains several hundred thousand stars within a volume of 10 to 30 light-years across. The Kitt Peak National Observatory's 0.9-meter telescope took this picture in March 1995. The box at left indicates the region observed by the Hubble telescope. The Hubble telescope studied a small region of the cluster. A section of that region is seen in the picture at bottom left. A sampling of an even smaller region is shown at bottom right. This region is only about one light-year across. In this smaller region, Hubble pinpointed a number of faint white dwarfs. The blue circles pinpoint the dwarfs. It took nearly eight days of exposure time over a 67-day period to find these extremely faint stars. Globular clusters are among the oldest clusters of stars in the universe. The faintest and coolest white dwarfs within globular clusters can yield a globular cluster's age. Earlier Hubble observations showed that the first stars formed less than 1 billion years after the universe's birth in the big bang. So, finding the oldest stars puts astronomers within arm's reach of the universe's age. M4 is 7,000 light-years away in the constellation Scorpius. Hubble's Wide Field and Planetary Camera 2 made the observations from January through April 2001. These optical observations were combined to

Identification of Hard X-ray Sources in Galactic Globular Clusters: Simbol-X Simulations

Science.gov (United States)

Servillat, M.

2009-05-01

Globular clusters harbour an excess of X-ray sources compared to the number of X-ray sources in the Galactic plane. It has been proposed that many of these X-ray sources are cataclysmic variables that have an intermediate magnetic field, i.e. intermediate polars, which remains to be confirmed and understood. We present here several methods to identify intermediate polars in globular clusters from multiwavelength analysis. First, we report on XMM-Newton, Chandra and HST observations of the very dense Galactic globular cluster NGC 2808. By comparing UV and X-ray properties of the cataclysmic variable candidates, the fraction of intermediate polars in this cluster can be estimated. We also present the optical spectra of two cataclysmic variables in the globular cluster M 22. The HeII (4868 Å) emission line in these spectra could be related to the presence of a magnetic field in these objects. Simulations of Simbol-X observations indicate that the angular resolution is sufficient to study X-ray sources in the core of close, less dense globular clusters, such as M 22. The sensitivity of Simbol-X in an extended energy band up to 80 keV will allow us to discriminate between hard X-ray sources (such as magnetic cataclysmic variables) and soft X-ray sources (such as chromospherically active binaries).

Integrated-light spectroscopy of globular clusters at the infrared Ca II lines

Science.gov (United States)

Armandroff, Taft E.; Zinn, Robert

1988-01-01

Integrated-light spectroscopy has been obtained for 27 globular clusters at the Ca II IR triplet. Line strengths and radial velocities have been measured from the spectra. For the well-studied clusters in the sample, the strength of the Ca II lines is very well correlated with previous metallicity estimates. Thus, the triplet is useful as a metallicity indicator in globular cluster integrated-light spectra. The greatly reduced effect of interstellar extinction at these wavelengths (compared to the blue region of the spectrum) has permitted observations of some of the most heavily reddened clusters in the Galaxy. For several such clusters, the Ca II triplet metallicities are in poor agreement with metallicity estimates from IR photometry by Malkan (1981). The strength of an interstellar band at 8621A has been used to estimate the amount of extinction towards these clusters. Using the new metallicity and radial-velocity data, the metallicity distribution, kinematics, and spatial distribution of the disk globular cluster system have been analyzed. Results very similar to those of Zinn (1985) have been found. The relation of the disk globulars to the stellar thick disk is discussed.

Disrupted globular clusters and the gamma-ray excess in the Galactic Centre

Science.gov (United States)

Fragione, Giacomo; Antonini, Fabio; Gnedin, Oleg Y.

2018-04-01

The Fermi Large Area Telescope has provided the most detailed view towards the Galactic Centre (GC) in high-energy gamma-rays. Besides the interstellar emission and point source contributions, the data suggest a residual diffuse gamma-ray excess. The similarity of its spatial distribution with the expected profile of dark matter has led to claims that this may be evidence for dark matter particle annihilation. Here, we investigate an alternative explanation that the signal originates from millisecond pulsars (MSPs) formed in dense globular clusters and deposited at the GC as a consequence of cluster inspiral and tidal disruption. We use a semi-analytical model to calculate the formation, migration, and disruption of globular clusters in the Galaxy. Our model reproduces the mass of the nuclear star cluster and the present-day radial and mass distribution of globular clusters. For the first time, we calculate the evolution of MSPs from disrupted globular clusters throughout the age of the Galaxy and consistently include the effect of the MSP spin-down due to magnetic-dipole braking. The final gamma-ray amplitude and spatial distribution are in good agreement with the Fermi observations and provide a natural astrophysical explanation for the GC excess.

The ellipticities of a sample of globular clusters in M31

International Nuclear Information System (INIS)

Lupton, R.H.

1989-01-01

Images for a sample of 18 globular clusters in M31 have been obtained. The mean ellipticity on the sky in the range 7-14 pc (2-4 arcsec) is 0.08 + or - 0.02 and 0.12 + or - 0.01 in the range 14-21 pc (4-6 arcsec), with corresponding true ellipticities of 0.12 and 0.18. The difference between the inner and outer parts is significant at a 99 percent level. The flattening of the inner parts is statistically indistinguishable from that of the Galactic globular clusters, while the outer parts are flatter than the Galactic clusters at a 99.8 percent confidence level. There is a significant anticorrelation of ellipticity with line strength; such a correlation may in retrospect also be seen in the Galactic globular cluster system. For the M31 data, this anticorrelation is stronger in the inner parts of the galaxy. 30 refs

Avaliação da reação de mitsuda em pacientes virchovianos inativos antes e após imunoterapia

Directory of Open Access Journals (Sweden)

Maria Sueli Parreira de Arruda

1995-09-01

Full Text Available Neste estudo investigou-se o potencial imunomodulador do levamisole e da mistura BCG/Mycobacterium leprae em pacientes virchovianos inativos, utilizando como parâmetro a reação de Mitsuda. Vinte pacientes, classificados como Mitsuda histologicamente negativos há 10 anos, foram divididos em três grupos: cinco pacientes que foram somente reavaliados frente a mitsudina: oito pacientes que receberam levamisole e, sete que receberam a mistura de BCG vivo mais M. leprae morto. Os resultados mostraram que: 1 o levamisole não alterou a reatividade à mitsudina em nenhum dos casos estudados; 2 as modificações da reatividade verificadas com o uso da mistura (tres casos ou aquelas que ocorreram espontaneamente (tres casos foram sempre de pequena amplitude e refletiram variações próprias de pacientes com algum grau de resistência ao Mycobacterium leprae.

The Frequency of Binary Stars in the Globular Cluster M71

Science.gov (United States)

Barden, S. C.; Armandroff, T. E.; Pryor, C. P.

1994-12-01

The frequency of binary stars is a fundamental property of a stellar population. A comparison of the frequency of binaries in globular clusters with those in the field halo and disk populations tests the similarity of star formation in those environments. Binary stars in globular clusters also act as an energy source which ``heats" the cluster through super-elastic encounters with other stars and binaries. Such encounters can not only profoundly affect the dynamical evolution of the cluster, they can disrupt the widely separated binaries and catalyze the formation of exotic objects such as blue stragglers, x-ray binaries, and milli-second pulsars. We have used the KPNO 4-m and the multi-fiber instruments Nessie and Hydra to measure radial velocities at 4 epochs over two years for a sample of 126 stars in the globular cluster M71. Velocity errors are under 1 km s(-1) for the brighter stars and under 2 km s(-1) for the majority of our data set. These velocities will be valuable for studying the kinematics of M71, but here we focus on searching for binaries. The faintest stars are at V=17, or just above the main sequence turnoff. Our sample is thus deeper than any published globular cluster binary search utilizing spectroscopic techniques. By observing smaller stars, we double the number of decades of binary periods sampled compared to previous studies and come within a factor of 4 of the shortest possible periods for turnoff stars. This wider period window has produced the largest known sample of binaries in a globular cluster. Four stars show velocity ranges larger than 20 km s(-1) , nine have ranges larger than 10 km s(-1) , and others are clearly variable. We will compare the radial distribution of these stars to that predicted by theory and derive the main-sequence binary fraction.

BtcA, A class IA type III chaperone, interacts with the BteA N-terminal domain through a globular/non-globular mechanism.

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Chen Guttman

Full Text Available Bordetella pertussis, the etiological agent of "whooping cough" disease, utilizes the type III secretion system (T3SS to deliver a 69 kDa cytotoxic effector protein, BteA, directly into the host cells. As with other T3SS effectors, prior to its secretion BteA binds BtcA, a 13.9 kDa protein predicted to act as a T3SS class IA chaperone. While this interaction had been characterized for such effector-chaperone pairs in other pathogens, it has yet to be fully investigated in Bordetella. Here we provide the first biochemical proof that BtcA is indeed a class IA chaperone, responsible for the binding of BteA's N-terminal domain. We bring forth extensive evidence that BtcA binds its substrate effector through a dual-interface binding mechanism comprising of non-globular and bi-globular interactions at a moderate micromolar level binding affinity. We demonstrate that the non-globular interactions involve the first 31 N-terminal residues of BteA287 and their removal leads to destabilization of the effector-chaperone complex and lower binding affinities to BtcA. These findings represent an important first step towards a molecular understanding of BteA secretion and cell entry.

Interdependence of the rad50 hook and globular domain functions.

Science.gov (United States)

Hohl, Marcel; Kochańczyk, Tomasz; Tous, Cristina; Aguilera, Andrés; Krężel, Artur; Petrini, John H J

2015-02-05

Rad50 contains a conserved Zn(2+) coordination domain (the Rad50 hook) that functions as a homodimerization interface. Hook ablation phenocopies Rad50 deficiency in all respects. Here, we focused on rad50 mutations flanking the Zn(2+)-coordinating hook cysteines. These mutants impaired hook-mediated dimerization, but recombination between sister chromatids was largely unaffected. This may reflect that cohesin-mediated sister chromatid interactions are sufficient for double-strand break repair. However, Mre11 complex functions specified by the globular domain, including Tel1 (ATM) activation, nonhomologous end joining, and DNA double-strand break end resection were affected, suggesting that dimerization exerts a broad influence on Mre11 complex function. These phenotypes were suppressed by mutations within the coiled-coil and globular ATPase domains, suggesting a model in which conformational changes in the hook and globular domains are transmitted via the extended coils of Rad50. We propose that transmission of spatial information in this manner underlies the regulation of Mre11 complex functions. Copyright © 2015 Elsevier Inc. All rights reserved.

The Age of Globular Clusters in Light of Hipparcos: Resolving the Age Problem?

Science.gov (United States)

Chaboyer, Brian; Demarque, P.; Kernan, Peter J.; Krauss, Lawrence M.

1998-02-01

We review five independent techniques that are used to set the distance scale to globular clusters, including subdwarf main-sequence fitting utilizing the recent Hipparcos parallax catalog. These data together all indicate that globular clusters are farther away than previously believed, implying a reduction in age estimates. We now adopt a best-fit value Mv (RR Lyrae stars) = 0.39 +/- 0.08 (statistical) at [Fe/H] = -1.9 with an additional uniform systematic uncertainty of +0.13-0.18. This new distance scale estimate is combined with a detailed numerical Monte Carlo study (previously reported by Chaboyer et al.) designed to assess the uncertainty associated with the theoretical age-turnoff luminosity relationship in order to estimate both the absolute age and uncertainty in age of the oldest globular clusters. Our best estimate for the mean age of the oldest globular clusters is now 11.5 +/- 1.3 Gyr, with a one-sided 95% confidence level lower limit of 9.5 Gyr. This represents a systematic shift of over 2 σ compared to our earlier estimate, owing completely to the new distance scale--a shift which we emphasize results not only from the Hipparcos data. This now provides a lower limit on the age of the universe that is consistent with either an open universe or with a flat matter-dominated universe (the latter requiring H0 explicitly quantifies how remaining uncertainties in the distance scale and stellar evolution models translate into uncertainties in the derived globular cluster ages. Simple formulae are provided that can be used to update our age estimate as improved determinations for various quantities become available. Formulae are also provided that can be used to derive the age and its uncertainty for a globular cluster, given the absolute magnitude of the turnoff or the point on the subgiant branch 0.05 mag redder than the turnoff.

Measuring age differences among globular clusters having similar metallicities - A new method and first results

International Nuclear Information System (INIS)

Vandenberg, D.A.; Bolte, M.; Stetson, P.B.

1990-01-01

A color-difference technique for estimating the relative ages of globular clusters with similar chemical compositions on the basis of their CM diagrams is described and demonstrated. The theoretical basis and implementation of the procedure are explained, and results for groups of globular clusters with m/H = about -2, -1.6, and -1.3, and for two special cases (Palomar 12 and NGC 5139) are presented in extensive tables and graphs and discussed in detail. It is found that the more metal-deficient globular clusters are nearly coeval (differences less than 0.5 Gyr), whereas the most metal-rich globular clusters exhibit significant age differences (about 2 Gyr). This result is shown to contradict Galactic evolution models postulating halo collapse in less than a few times 100 Myr. 77 refs

A spectroscopic and photometric study of MSP companions in Galactic Globular Clusters

OpenAIRE

Cocozza, Gabriele

2008-01-01

This Thesis is devoted to the study of the optical companions of Millisecond Pulsars in Galactic Globular Clusters (GCs) as a part of a large project started at the Department of Astronomy of the Bologna University, in collaboration with other institutions (Astronomical Observatory of Cagliari and Bologna, University of Virginia), specifically dedicated to the study of the environmental effects on passive stellar evolution in galactic GCs. Globular Clusters are very efficien...

Is age really the second parameter in globular clusters?

International Nuclear Information System (INIS)

Vandenberg, D.A.; Durrell, P.R.

1990-01-01

From the close similarity of the magnitude difference between the tip of the red giant branch and the turnoff in the Fe/H = about -1.3 globular cluster NGC 288, NGC 362, and M5, it is inferred that the ages of these three systems (and Palomar 5, whose horizonal branch is used to define its distance relative to the others) are not detectably different. An identical conclusion, by similar means, is reached for the Fe/H = about -2.1 globular clusters M15, M30, M68, and M92. Several recent claims that age is responsible for the wide variation in horizontal-branch morphology among clusters of the same metal abundance are not supported. 73 refs

Ruprecht 106 - A young metal-poor Galactic globular cluster

International Nuclear Information System (INIS)

Buonanno, R.; Buscema, G.; Fusi Pecci, F.; Richer, H.B.; Fahlman, G.G.

1990-01-01

The first CCD photometric survey in the Galactic globular cluster Ruprecht 106 has been performed. The results show that Ruprecht 106 is a metal-poor cluster with (Fe/H) about -2 located at about 25 kpc from the Galactic center. A sizable, high centrally concentrated population of blue stragglers was detected. Significant differences in the positions of the turnoffs in the color-magnitude diagram are found compared to those in metal-poor clusters. The cluster appears younger than other typical metal-poor Galactic globulars by about 4-5 Gyr; if true, this object would represent the first direct proof of the existence of a significant age spread among old, very metal-poor clusters. 51 refs

Color maps of X-ray globular clusters

International Nuclear Information System (INIS)

Bailyn, C.D.; Grindlay, J.E.; Cohn, H.; Lugger, P.M.

1988-01-01

The results of a search for optical counterparts to X-ray sources in six globular clusters, 47 Tuc, NGC 1851, NGC 6441, NGC 6624, NGC 6712, and M15, are reported. Maps of the U-B color of the central regions of the clusters were prepared. A candidate for the optical counterpart of the source in NGC 6712 was found, along with a blue region near the X-ray source in 47 Tuc. Upper limits on the colors and magnitudes of possible optical counterparts are reported for the other three clusters. The use of color maps to determine color gradients in globular clusters is explored. It is found that, while such gradients do exist and vary from cluster to cluster, they can be explained by crowding effects. Crude limits are placed on the excess populations of blue objects such as CVs, which have been postulated to be concentrated in the centers of dense clusters. 32 references

Human diploid fibroblasts have receptors for the globular domain of C1Q

International Nuclear Information System (INIS)

Bordin, S.; Page, R.C.

1986-01-01

The authors showed that mass cultures of fibroblasts grown from gingival explants in DB medium with 10% human serum are enriched in a phenotype that binds C1q with an affinity much higher than the rest of the population. Because of potential biologic importance of C1q receptors, the authors studied whether the interaction between C1q and this phenotype was mediated by the globular or collagenous domains of the molecule. Globular fragments were prepared by digesting C1q with collagenase, and collagenous fragments obtained after pepsin treatment. C1q binding on cells in suspension was determined by reaction with 125 I-C1q as reported. Competition experiments were performed under conditions in which intact 125 I-C1q binding saturated all available receptors. The results showed that collagenous fragments inhibited 20% of the 125 I-C1q binding to high affinity receptors, whereas inhibition by globular fragments was 70%. Unlabeled intact C1q and collagen type 1 were used as controls, and inhibited 92% and 17% of C1q binding, respectively. These studies show that C1q interacts with the fibroblast phenotype expressing high affinity receptors through its globular domain. The authors suggest that at sites of trauma, native C1 may bind to the surface of these cells via the globular domain of C1q, and that this unique phenotype may play an important role in tissue repair

Misturas NR/SBR: modos de preparação e propriedades

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Visconte Leila L. Y.

2001-01-01

Full Text Available Aplicações de artefatos de borracha muitas vezes requerem um conjunto de propriedades que não podem ser fornecidas por um único elastômero sendo, então necessário, que misturas de dois ou mais polímeros sejam empregadas. Nesses casos, os demais ingredientes que normalmente são adicionados, distribuem-se de modo diferente dependendo de sua afinidade com cada uma das borrachas. O grau de dispersão de cada um desses ingredientes em cada fase elastomérica irá influenciar a velocidade e o grau de vulcanização e, certamente, terá conseqüências sobre o desempenho do composto final. Neste trabalho, a borracha natural (NR foi misturada ao elastômero de butadieno-estireno (SBR na proporção de 1:1 em peso. As composições foram preparadas em misturador de cilindros, segundo a norma ASTM D 3182, empregando-se quatro maneiras distintas para a incorporação dos aditivos. Após a vulcanização foram estudadas propriedades mecânicas, como resistências à tração e ao rasgamento e dureza, propriedades termo-dinâmico-mecânicas e a morfologia de cada uma das composições. As propriedades mecânicas foram avaliadas de acordo com as normas ASTM específicas para cada ensaio. Os resultados mostram que, apesar de se usar a mesma formulação, o modo de preparo tem grande influência sobre as propriedades, o que é detectável pelas propriedades mecânicas e pela análise morfológica, e evidenciado através de testes sensíveis, como o dinâmico-mecânico. No caso da mistura NR/SBR as melhores propriedades são obtidas quando é favorecida a vulcanização da borracha que, isoladamente, apresenta propriedades inferiores.

Competição de misturas de herbicidas nas principais regiões algodoeiras (Gossypium hirsutum L. no E. de Minas Gerais

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J.P. del C. Laca-Buendia

1978-09-01

Full Text Available Com a finalidade de testar misturas de herbicidas, aplicados em pré-plantio incorporado e préemergência na cultura algodoeira, instalaram-se no ano agrícola 74/75, três ensaios. Usaram-se no plantio as cultivares IAC-13-1 (Triângulo e Norte e Minas Dona Beja (Metalúrgica. Acanthospermum australe foi a planta daninha de mais difícil controle. Somente a mistura de tanque de alachlor a 2,00 kg/ha e linuron a 0,75 kg/ha foi eficiente no seu controle. No Triângulo Mineiro, para o total das plantas daninhas somente houve controle até os 30 dias, sendo as melhores misturas: dinitramine + diuron; dinitroanilin + prometryne e pendimethalin + diuron, sendo esse controle de 96,2%, 92,5% e 96,2% respectivamente. Com relação aos rendimentos, o melhor tratamento foi pendimetalin + diuron, com 1962 kg/ha contra 1130 kg/ha da testemunha sem capina. No Norte de Minas Gerais, para o total das plantas daninhas, as melhores misturas foram pendimethalin + diuron com controle de 86,4% aos 30 dias, 83,6% aos 50 dias e 70,3% aos 80 dias após a aplicação. Com relação aos rendimentos as misturas de dinitramine + fluometuron e dinitroanilin + fluometuron produziram respectivamente 1532 kg/ha e 1451 kg/ha contra 229 kg/ha da testemunha sem capina. Na Região Metalúrgica, para o controle total das plantas daninhas a mistura mais eficiente foi dinitramine + diuron, com controle de 67% até os 30 dias após a aplicação. Depois de 50 dias, seu efeito não foi satisfatório. Com relação ao rendimento, a mistura dinitramine + fluometuron produziu 831 kg/ha, contra 145 kg/ha da testemunha sem capina. Em todos os locais a altura das plantas foi afetada pela competição das plantas daninhas. O peso do tapulho e de 100 sementes foram efetados somente na região Metalúrgica, para os tratamentos sem controle sobre as mesmas. Para índice de fibra, percentagem de fibra, comprimento da fibra, índice Pressle y, índice Micronaire e maturidade da fibra em nenhuma

Keck Spectroscopy of Globular Clusters in the Elliptical Galaxy NGC 3610

OpenAIRE

Strader, Jay; Brodie, Jean P.; Schweizer, Francois; Larsen, Soeren S.; Seitzer, Patrick

2002-01-01

We present moderate-resolution Keck spectra of nine candidate globular clusters in the possible merger-remnant elliptical galaxy NGC 3610. Eight of the objects appear to be bona fide globular clusters of NGC 3610. We find that two of the clusters belong to an old metal-poor population, five to an old metal-rich population, and only one to an intermediate-age metal-rich population. The estimated age of the intermediate-age cluster is 1-5 Gyr, which is in agreement with earlier estimates of the...

Equilibrio liquido-liquido-vapor de misturas ternarias : algoritimo de calculo e aspectos termodinamicos

OpenAIRE

Maria Helena Cano de Andrade

1991-01-01

Resumo: Este trabalho é uma contribuição ao estudo de processos de separação envolvendo fases em equilibrio liquido-liquido-vapor. Os seguintes aspectos são abordados: (1) desenvolvimento de um algoritmo eficiente de cálculo de flash liquido-liquido-vapor e sua aplicação para gerar diagramas de fases e em cálculos de destilação; (2) avaliação da utilização de parâmetros binários do modelo UNIQUAC obtidos de dados bifásicos em cálculos trifásicos de misturas ternárias; (3) medidas experimentai...

Speckle imaging of globular clusters

International Nuclear Information System (INIS)

Sams, B.J. III

1990-01-01

Speckle imaging is a powerful tool for high resolution astronomy. Its application to the core regions of globular clusters produces high resolution stellar maps of the bright stars, but is unable to image the faint stars which are most reliable dynamical indicators. The limits on resolving these faint, extended objects are physical, not algorithmic, and cannot be overcome using speckle. High resolution maps may be useful for resolving multicomponent stellar systems in the cluster centers. 30 refs

Globular cluster seeding by primordial black hole population

Energy Technology Data Exchange (ETDEWEB)

Dolgov, A. [ITEP, Bol. Cheremushkinsaya ul., 25, 117218 Moscow (Russian Federation); Postnov, K., E-mail: dolgov@fe.infn.it, E-mail: kpostnov@gmail.com [Sternberg Astronomical Institute, Moscow M.V. Lomonosov State University, Universitetskij pr., 13, Moscow 119234 (Russian Federation)

2017-04-01

Primordial black holes (PBHs) that form in the early Universe in the modified Affleck-Dine (AD) mechanism of baryogenesis should have intrinsic log-normal mass distribution of PBHs. We show that the parameters of this distribution adjusted to provide the required spatial density of massive seeds (≥ 10{sup 4} M {sub ⊙}) for early galaxy formation and not violating the dark matter density constraints, predict the existence of the population of intermediate-mass PBHs with a number density of 0∼ 100 Mpc{sup −3}. We argue that the population of intermediate-mass AD PBHs can also seed the formation of globular clusters in galaxies. In this scenario, each globular cluster should host an intermediate-mass black hole with a mass of a few thousand solar masses, and should not obligatorily be immersed in a massive dark matter halo.

Misturas binárias e ternárias de gorduras hidrogenadas e óleo de soja Binary and ternary blends of hydrogenated fats and soybean oil

Directory of Open Access Journals (Sweden)

Ilka Sumiyoshi SIMÕES

1997-12-01

Full Text Available Na formulação de produtos gordurosos, é comum a mistura de óleos e gorduras, para se alcançar as especificações do produto final. As interações que ocorrem entre os triacilgliceróis nas misturas promovem alterações nas propriedades físicas das gorduras. Comparado às técnicas tradicionais, os experimentos planejados poupam tempo e recursos, identificam pontos ótimos verdadeiros, e permitem que os efeitos das variáveis individuais ou interações entre elas sejam determinados. O objetivo do trabalho foi estudar interações que ocorrem em misturas binárias e ternárias de duas gorduras hidrogenadas (FATGILL PF38 e FATGILL PF42 e um óleo de soja, analisando suas propriedades físicas e químicas. Foram elaboradas 10 misturas, representadas por 3 amostras individuais, 3 misturas binárias e 4 misturas ternárias. As amostras foram analisadas quanto aos ácidos graxos, índices de iodo e saponificação, pontos de amolecimento e fusão, viscosidade cinemática, dureza e consistência. Aplicou-se, para algumas respostas, um modelo de regressão múltipla do tipo cúbico especial. A análise dos resultados indicou que as interações entre os três componentes não foram significativas. A dureza dependeu apenas da gordura hidrogenada FATGILL PF42. Por outro lado, a viscosidade foi dependente dos três componentes, enquanto os pontos de fusão e amolecimento foram decorrentes das gorduras hidrogenadas. Os coeficientes negativos para a propriedade de dureza demonstraram um efeito antagônico, característico das interações eutéticas entre gorduras. Estabeleceram-se, ainda, diagramas triangulares, onde foram indicadas curvas de nível. Um modelo perfeito de mistura foi evidenciado para a viscosidade e pontos de amolecimento e de fusão.In the formulation of fat products, it is an usual practice the blending of oils and fats, to meet final product specifications. Alterations in fat mixtures properties are advanced by triacylglycerols

New bound on neutrino dipole moments from globular-cluster stars

Science.gov (United States)

Raffelt, Georg G.

1990-01-01

Neutrino dipole moments mu(nu) would increase the core mass of red giants at the helium flash by delta(Mc) = 0.015 solar mass x mu(nu)/10 to the -12th muB (where muB is the Bohr magneton) because of enhanced neutrino losses. Existing measurements of the bolometric magnitudes of the brightest red giants in 26 globular clusters, number counts of horizontal-branch stars and red giants in 15 globular clusters, and statistical parallax determinations of field RR Lyr luminosities yield delta(Mc) = 0.009 + or - 0.012 solar mass, so that conservatively mu(nu) is less than 3 x 10 to the -12th muB.

MOCK OBSERVATIONS OF BLUE STRAGGLERS IN GLOBULAR CLUSTER MODELS

International Nuclear Information System (INIS)

Sills, Alison; Glebbeek, Evert; Chatterjee, Sourav; Rasio, Frederic A.

2013-01-01

We created artificial color-magnitude diagrams of Monte Carlo dynamical models of globular clusters and then used observational methods to determine the number of blue stragglers in those clusters. We compared these blue stragglers to various cluster properties, mimicking work that has been done for blue stragglers in Milky Way globular clusters to determine the dominant formation mechanism(s) of this unusual stellar population. We find that a mass-based prescription for selecting blue stragglers will select approximately twice as many blue stragglers than a selection criterion that was developed for observations of real clusters. However, the two numbers of blue stragglers are well-correlated, so either selection criterion can be used to characterize the blue straggler population of a cluster. We confirm previous results that the simplified prescription for the evolution of a collision or merger product in the BSE code overestimates their lifetimes. We show that our model blue stragglers follow similar trends with cluster properties (core mass, binary fraction, total mass, collision rate) as the true Milky Way blue stragglers as long as we restrict ourselves to model clusters with an initial binary fraction higher than 5%. We also show that, in contrast to earlier work, the number of blue stragglers in the cluster core does have a weak dependence on the collisional parameter Γ in both our models and in Milky Way globular clusters

Discovery of a ~205 Hz X-ray pulsar in the globular cluster NGC 6440

NARCIS (Netherlands)

Altamirano, D.; Strohmayer, T.E.; Heinke, C.O.; Markwardt, C.B.; Swank, J.H.; Pereira, D.; Smith, E.; Wijnands, R.; Linares, M.; Patruno, A.; Casella, P.; van der Klis, M.

2009-01-01

Discovery of a 205 Hz X-ray pulsar in the globular cluster NGC 6440 The globular cluster NGC 6440 was observed by the PCA instrument aboard RXTE on August 30, 2009 at 01:42 (UTC). The observation lasted for approximately 3000 seconds and the source was detected with an intensity of ~7 mCrab (2-10

VARIABLE STARS IN LARGE MAGELLANIC CLOUD GLOBULAR CLUSTERS. II. NGC 1786

International Nuclear Information System (INIS)

Kuehn, Charles A.; Smith, Horace A.; De Lee, Nathan; Catelan, Márcio; Pritzl, Barton J.; Borissova, Jura

2012-01-01

This is the second in a series of papers studying the variable stars in Large Magellanic Cloud globular clusters. The primary goal of this series is to study how RR Lyrae stars in Oosterhoff-intermediate systems compare to their counterparts in Oosterhoff I/II systems. In this paper, we present the results of our new time-series B–V photometric study of the globular cluster NGC 1786. A total of 65 variable stars were identified in our field of view. These variables include 53 RR Lyraes (27 RRab, 18 RRc, and 8 RRd), 3 classical Cepheids, 1 Type II Cepheid, 1 Anomalous Cepheid, 2 eclipsing binaries, 3 Delta Scuti/SX Phoenicis variables, and 2 variables of undetermined type. Photometric parameters for these variables are presented. We present physical properties for some of the RR Lyrae stars, derived from Fourier analysis of their light curves. We discuss several different indicators of Oosterhoff type which indicate that the Oosterhoff classification of NGC 1786 is not as clear cut as what is seen in most globular clusters.

A 5.75-millisecond pulsar in the globular cluster 47 Tucanae

International Nuclear Information System (INIS)

Manchester, R.N.; Lyne, A.G.; Johnston, S.; D'Amico, N.; Lim, J.; Kniffen, D.A.

1990-01-01

Millisecond pulsars are generally believed to be old pulsars that have been spun up ('recycled') as a result of accretion of matter from a companion in a low-mass X-ray binary system. As there is a high incidence of such systems in globular clusters, these are good places to search for millisecond pulsars; so far, ten globular-cluster pulsars have been detected unambiguously. Using the Parkes radiotelescope in Australia, we have found a pulsar with a period of 5.75 ms and a dispersion measure of 25 cm -3 pc in the direction of 47 Tucanae. Despite its probable origin as a member of a binary system, timing measurements show that the pulsar is now single. The observed dispersion measure is consistent with the pulsar lying outside the galactic electron layer and within 47 Tucanae; but it is very different from the value of 67 cm -3 pc for the pulsars that were reported recently as being in this globular cluster, and we suggest that the latter pulsars probably do not in fact lie within 47 Tucanae. (author)

THE SIZE DIFFERENCE BETWEEN RED AND BLUE GLOBULAR CLUSTERS IS NOT DUE TO PROJECTION EFFECTS

International Nuclear Information System (INIS)

Webb, Jeremy J.; Harris, William E.; Sills, Alison

2012-01-01

Metal-rich (red) globular clusters in massive galaxies are, on average, smaller than metal-poor (blue) globular clusters. One of the possible explanations for this phenomenon is that the two populations of clusters have different spatial distributions. We test this idea by comparing clusters observed in unusually deep, high signal-to-noise images of M87 with a simulated globular cluster population in which the red and blue clusters have different spatial distributions, matching the observations. We compare the overall distribution of cluster effective radii as well as the relationship between effective radius and galactocentric distance for both the observed and simulated red and blue sub-populations. We find that the different spatial distributions does not produce a significant size difference between the red and blue sub-populations as a whole or at a given galactocentric distance. These results suggest that the size difference between red and blue globular clusters is likely due to differences during formation or later evolution.

The Size Difference between Red and Blue Globular Clusters is not due to Projection Effects

Science.gov (United States)

Webb, Jeremy J.; Harris, William E.; Sills, Alison

2012-11-01

Metal-rich (red) globular clusters in massive galaxies are, on average, smaller than metal-poor (blue) globular clusters. One of the possible explanations for this phenomenon is that the two populations of clusters have different spatial distributions. We test this idea by comparing clusters observed in unusually deep, high signal-to-noise images of M87 with a simulated globular cluster population in which the red and blue clusters have different spatial distributions, matching the observations. We compare the overall distribution of cluster effective radii as well as the relationship between effective radius and galactocentric distance for both the observed and simulated red and blue sub-populations. We find that the different spatial distributions does not produce a significant size difference between the red and blue sub-populations as a whole or at a given galactocentric distance. These results suggest that the size difference between red and blue globular clusters is likely due to differences during formation or later evolution.

Efeito compatibilizante de copolímeros contendo segmentos líquido-cristalinos em misturas com poli(tereftalato de etileno e um poliéster líquido-cristalino termotrópico (TLCP

Directory of Open Access Journals (Sweden)

Novack Kátia M.

1999-01-01

Full Text Available Uma série de copolímeros com segmentos líquido-cristalinos foram sintetizados por policondensação em solução a alta temperatura e misturados com poli(tereftalato de etileno (PET e um poliéster líquido-cristalino termotrópico (TLCP, previamente sintetizado. Os copolímeros foram utilizados com sucesso como compatibilizantes nas misturas PET/TLCP. As técnicas de caloria diferencial de varredura, análises dinâmico-mecânicas, análises térmicas e microscopia eletrônica (SEM foram utilizadas na caracterização dos polímeros. Foi verificada boa processabilidade e diminuição da velocidade de cristalização das misturas. As micrografias das superfícies fraturadas das amostras, obtidas das análises de SEM, mostraram melhor miscibilidade para as misturas com maior teor de copolímero.

NGC 6273: Towards Defining A New Class of Galactic Globular Clusters?

Science.gov (United States)

Johnson, Christian I.; Rich, Robert Michael; Pilachowski, Catherine A.; Caldwell, Nelson; Mateo, Mario L.; Ira Bailey, John; Crane, Jeffrey D.

2016-01-01

A growing number of observations have found that several Galactic globular clusters exhibit abundance dispersions beyond the well-known light element (anti-)correlations. These clusters tend to be very massive, have >0.1 dex intrinsic metallicity dispersions, have complex sub-giant branch morphologies, and have correlated [Fe/H] and s-process element enhancements. Interestingly, nearly all of these clusters discovered so far have [Fe/H]~-1.7. In this context, we have examined the chemical composition of 18 red giant branch (RGB) stars in the massive, metal-poor Galactic bulge globular cluster NGC 6273 using high signal-to-noise, high resolution (R~27,000) spectra obtained with the Michigan/Magellan Fiber System (M2FS) and MSpec spectrograph mounted on the Magellan-Clay 6.5m telescope at Las Campanas Observatory. We find that the cluster exhibits a metallicity range from [Fe/H]=-1.80 to -1.30 and is composed of two dominant populations separated in [Fe/H] and [La/Fe] abundance. The increase in [La/Eu] as a function of [La/H] suggests that the increase in [La/Fe] with [Fe/H] is due to almost pure s-process enrichment. The most metal-rich star in our sample is not strongly La-enhanced, but is α-poor and may belong to a third "anomalous" stellar population. The two dominant populations exhibit the same [Na/Fe]-[Al/Fe] correlation found in other "normal" globular clusters. Therefore, NGC 6273 joins ω Centauri, M 22, M 2, and NGC 5286 as a possible new class of Galactic globular clusters.

Mistura em tanque de boro e herbicidas em semeadura convencional de girassol Tank-mix of boron and herbicides on conventional sunflower sowing

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C. Castro

2002-04-01

Full Text Available Os objetivos deste experimento foi avaliar a resposta do girassol às aplicações de boro (B, isoladas ou em mistura com herbicidas, e o controle de plantas daninhas por meio de experimento conduzido na Embrapa Soja, Londrina-PR. Os tratamentos foram acetochlor (1,92 kg i.a. ha-1, oxyfluorfen (0,36 kg i.a. ha-1, sulfentrazone (0,35 kg i.a.ha-1, trifluralin (1,80 kg i.a. ha-1 e as testemunhas capinada e sem capina. Todos os tratamentos foram aplicados, isoladamente ou em mistura, com 2 kg ha-1 de B (Na2B4O7.10H2 0 - bórax e H3BO3 - ácido bórico. O tratamento mais eficiente foi acetochlor mais ácido bórico; essa combinação resultou em solução mais homogênea da calda de pulverização, quando comparada com os herbicidas mais bórax. O herbicida acetochlor aplicado isoladamente ou em mistura com as duas fontes de B foi eficiente no controle da trapoeraba (Commelina benghalensis, do picão-preto (Bidens pilosa e da corda-de-viola (Ipomoea grandifolia. Os herbicidas oxyfluorfen e sulfentrazone, aplicados isoladamente ou em misturas com as duas fontes de B, foram eficientes no controle do amendoim-bravo (Euphorbia heterophylla e da corda-de-viola, respectivamente. É viável a aplicação de boro juntamente com os herbicidas testados nesta pesquisa em mistura em tanque, evitando a deficiência desse micronutriente e controlando as plantas daninhas na cultura do girassol.The objectives of this study were to determine the response of sunflower to application of boron (B fertilizer and herbicides, alone or in combination, and to determine its weed control. A field experiment was carried out at Embrapa Soja, Londrina, Parana, Brazil. The treatments were acetochlor (1.92 kg a.i. ha-1, oxyfluorfen (0.36 kg a.i. ha-1, sulfentrazone (0.35 kg a.i. ha-1, trifluralin (1.80 kg a.i. ha-1 and two controls (with and without hoeing. All treatments were applied alone or in combination with 2 kg ha-1 of B (Na2B4O7.10H2 0 - borax and H3BO3 - boric acid

Edades relativas de cúmulos globulares

Science.gov (United States)

Miller Bertolami, M.; Forte, J. C.

El trabajo de Rossemberg et al (1999), estudia las edades relativas de cúmulos globulares galácticos mediante el análisis de ciertos parámetros morfológicos de los diagramas color-magnitud de dichos cúmulos. Este trabajo se centra en tres puntos: analizar la consistencia de los resultados obtenidos por Rossemberg et al (1999) al emplear observaciones en el sistema fotométrico de Washington, más precisamente, las magnitudes C y T1 en lugar de las magnitudes V e I utilizadas por dichos autores. De la existencia de colores integrados, metalicidad y edad (relativa) para 21 de los cúmulos utilizados en dicho trabajo, se analiza la consistencia de estos resultados con las dependencias de color integrado como función de la edad y la metalicidad que se desprenden de los modelos teóricos de luz integrada por Worthey (1994), Schulz (2002) y Lee et al (2002). Por último se lleva a cabo una breve comparación de la morfología de los diagramas color-magnitud de los cúmulos globulares y de las isocronas utilizadas, a fin de intentar identificar algunas de las posibles causas de las diferencias observadas en los incisos anteriores.

Theoretical stellar luminosity functions and globular cluster ages and compositions

International Nuclear Information System (INIS)

Ratcliff, S.J.

1985-01-01

The ages and chemical compositions of the stars in globular clusters are of great interest, particularly because age estimates from the well-known exercise of fitting observed color-magnitude diagrams to theoretical predictions tend to yield ages in excess of the Hubble time (an estimate to the age of the Universe) in standard cosmological models, for currently proposed high values of Hubble's constant (VandenBerg 1983). Relatively little use has been made of stellar luminosity functions of the globular clusters, for which reliable observations are now becoming available, to constrain the ages or compositions. The comparison of observed luminosity functions to theoretical ones allows one to take advantage of information not usually used, and has the advantage of being relatively insensitive to our lack of knowledge of the detailed structure of stellar envelopes and atmospheres. A computer program was developed to apply standard stellar evolutionary theory, using the most recently available input physics (opacities, nuclear reaction rates), to the calculation of the evolution of low-mass Population II stars. An algorithm for computing luminosity functions from the evolutionary tracks was applied to sets of tracks covering a broad range of chemical compositions and ages, such as may be expected for globular clusters

Otimização dos tempos de mistura e decantação no processo de coagulação/floculação da água bruta por meio da Moringa oleifera Lam = Otimizing mixture and decantation times in the process of coagulation/flocculation of raw water using Moringa oleifera Lam

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Karina Cordeiro Cardoso

2008-07-01

Full Text Available Diversos coagulantes/floculantes estão sendo estudados ao que se refere à remoção de cor e turbidez da água bruta, entretanto, os coagulantes naturais têm demonstrado vantagens em relação aos químicos. A Moringa oleifera Lam é um polímero natural que vemganhando destaque no tratamento de água, pois atua como agente clarificante pela presença de uma proteína catiônica que desestabiliza as partículas contidas na água em meio líquido. Estetrabalho propõe a otimização dos tempos de coagulação, floculação e decantação, utilizando como coagulante diferentes concentrações da solução extraída da polpa da semente de Moringa oleifera Lam, para verificar a eficiência de remoção da cor e turbidez da água. Os ensaios foram realizados em “Jar Test”, utilizando diferentes tempos de mistura e decantação, com várias concentrações do biopolímero. Verificou-se que o tempo para propiciar a mistura rápida elenta, assim como a concentração do coagulante influenciaram a remoção dos parâmetros durante a coagulação/floculação/sedimentação.Several natural coagulants/flocculants are being studied to remove color and turbidity from raw water; however, natural coagulants have demonstrated advantages over chemical ones. Moringa oleifera Lam is a natural polymer that has become an important alternative in watertreatment, acting as a clarifying agent due to the presence of a cationic protein that destabilizes the particles contained in water in liquid form. This work proposes the optimization of the coagulation, flocculation and decantation times, using differentconcentrations of the solution extracted from the pulp of Moringa oleifera Lam seeds as coagulant, in order to verify its efficiency in removing color and turbidity from water. Jar tests were carried out, using different mixture and decantation times, with varyingconcentrations of the biopolymer. It was verified that the time required to achieve a fast and slow

The Observational and Theoretical Tidal Radii of Globular Clusters in M87

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Webb, Jeremy J.; Sills, Alison; Harris, William E.

2012-02-01

Globular clusters have linear sizes (tidal radii) which theory tells us are determined by their masses and by the gravitational potential of their host galaxy. To explore the relationship between observed and expected radii, we utilize the globular cluster population of the Virgo giant M87. Unusually deep, high signal-to-noise images of M87 are used to measure the effective and limiting radii of approximately 2000 globular clusters. To compare with these observations, we simulate a globular cluster population that has the same characteristics as the observed M87 cluster population. Placing these simulated clusters in the well-studied tidal field of M87, the orbit of each cluster is solved and the theoretical tidal radius of each cluster is determined. We compare the predicted relationship between cluster size and projected galactocentric distance to observations. We find that for an isotropic distribution of cluster velocities, theoretical tidal radii are approximately equal to observed limiting radii for R gc < 10 kpc. However, the isotropic simulation predicts a steep increase in cluster size at larger radii, which is not observed in large galaxies beyond the Milky Way. To minimize the discrepancy between theory and observations, we explore the effects of orbital anisotropy on cluster sizes, and suggest a possible orbital anisotropy profile for M87 which yields a better match between theory and observations. Finally, we suggest future studies which will establish a stronger link between theoretical tidal radii and observed radii.

THE OBSERVATIONAL AND THEORETICAL TIDAL RADII OF GLOBULAR CLUSTERS IN M87

International Nuclear Information System (INIS)

Webb, Jeremy J.; Sills, Alison; Harris, William E.

2012-01-01

Globular clusters have linear sizes (tidal radii) which theory tells us are determined by their masses and by the gravitational potential of their host galaxy. To explore the relationship between observed and expected radii, we utilize the globular cluster population of the Virgo giant M87. Unusually deep, high signal-to-noise images of M87 are used to measure the effective and limiting radii of approximately 2000 globular clusters. To compare with these observations, we simulate a globular cluster population that has the same characteristics as the observed M87 cluster population. Placing these simulated clusters in the well-studied tidal field of M87, the orbit of each cluster is solved and the theoretical tidal radius of each cluster is determined. We compare the predicted relationship between cluster size and projected galactocentric distance to observations. We find that for an isotropic distribution of cluster velocities, theoretical tidal radii are approximately equal to observed limiting radii for R gc < 10 kpc. However, the isotropic simulation predicts a steep increase in cluster size at larger radii, which is not observed in large galaxies beyond the Milky Way. To minimize the discrepancy between theory and observations, we explore the effects of orbital anisotropy on cluster sizes, and suggest a possible orbital anisotropy profile for M87 which yields a better match between theory and observations. Finally, we suggest future studies which will establish a stronger link between theoretical tidal radii and observed radii.

Pyroelectricity in globular protein lysozyme films

Science.gov (United States)

Stapleton, A.; Noor, M. R.; Haq, E. U.; Silien, C.; Soulimane, T.; Tofail, S. A. M.

2018-03-01

Pyroelectricity is the ability of certain non-centrosymmetric materials to generate an electric charge in response to a change in temperature and finds use in a range of applications from burglar alarms to thermal imaging. Some biological materials also exhibit pyroelectricity but the examples of the effect are limited to fibrous proteins, polypeptides, and tissues and organs of animals and plants. Here, we report pyroelectricity in polycrystalline aggregate films of lysozyme, a globular protein.

Short-term X-ray variability of the globular cluster source 4U 1820 - 30 (NGC 6624)

Science.gov (United States)

Stella, L.; Kahn, S. M.; Grindlay, J. E.

1984-01-01

Analytical techniques for improved identification of the temporal and spectral variability properties of globular cluster and galactic bulge X-ray sources are described in terms of their application to a large set of observations of the source 4U 1820 - 30 in the globular cluster NGC 6624. The autocorrelation function, cross-correlations, time skewness function, erratic periodicities, and pulse trains are examined. The results are discussed in terms of current models with particular emphasis on recent accretion disk models. It is concluded that the analyzed observations provide the first evidence for shot-noise variability in a globular cluster X-ray source.

Tidal stripping stellar substructures around four metal-poor globular clusters in the galactic bulge

International Nuclear Information System (INIS)

Chun, Sang-Hyun; Kang, Minhee; Jung, DooSeok; Sohn, Young-Jong

2015-01-01

We investigate the spatial density configuration of stars around four metal-poor globular clusters (NGC 6266, NGC 6626, NGC 6642, and NGC 6723) in the Galactic bulge region using wide-field deep J, H, and K imaging data obtained with the Wide Field Camera near-infrared array on the United Kingdom Infrared Telescope. A statistical weighted filtering algorithm for the stars on the color–magnitude diagram is applied in order to sort cluster member candidates from the field star contamination. In two-dimensional isodensity contour maps of the clusters, we find that all four of the globular clusters exhibit strong evidence of tidally stripped stellar features beyond the tidal radius in the form of tidal tails or small density lobes/chunks. The orientations of the extended stellar substructures are likely to be associated with the effect of dynamic interaction with the Galaxy and the cluster's space motion. The observed radial density profiles of the four globular clusters also describe the extended substructures; they depart from theoretical King and Wilson models and have an overdensity feature with a break in the slope of the profile at the outer region of clusters. The observed results could imply that four globular clusters in the Galactic bulge region have experienced strong environmental effects such as tidal forces or bulge/disk shocks of the Galaxy during the dynamical evolution of globular clusters. These observational results provide further details which add to our understanding of the evolution of clusters in the Galactic bulge region as well as the formation of the Galaxy.

Mistura, Identidade e Memória na Alimentação de Imigrantes Brasileiros em Barcelona

OpenAIRE

da Silva, Marilda Checcucci Gonçalves

2013-01-01

Resumo: no artigo se apresentam resultados de pesquisa com imigrantes brasileiros em Barcelona (ES) sobre seu processo de adaptação alimentar. Nela constatou-se que a comida além de se constituir em um marcador identitário, ao diferenciar a comida de ??um prato só?? (espanhola) da comida brasileira, que ??mistura tudo??, se encontra vinculada com a memória e a saudade das relações familiares que ocorrem em torno da comida. Palavras-chave: Comida. Identidade. Memória. Imigrantes brasi...

Testing modified gravity with globular clusters: the case of NGC 2419

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Llinares, Claudio

2018-05-01

The dynamics of globular clusters has been studied in great detail in the context of general relativity as well as with modifications of gravity that strongly depart from the standard paradigm such as Modified Newtonian Dynamics. However, at present there are no studies that aim to test the impact that less extreme modifications of gravity (e.g. models constructed as alternatives to dark energy) have on the behaviour of globular clusters. This Letter presents fits to the velocity dispersion profile of the cluster NGC 2419 under the symmetron-modified gravity model. The data show an increase in the velocity dispersion towards the centre of the cluster which could be difficult to explain within general relativity. By finding the best-fitting solution associated with the symmetron model, we show that this tension does not exist in modified gravity. However, the best-fitting parameters give a model that is inconsistent with the dynamics of the Solar system. Exploration of different screening mechanisms should give us the chance to understand if it is possible to maintain the appealing properties of the symmetron model when it comes to globular clusters and at the same time recover the Solar system dynamics properly.

Desempenho comparativo de um motor de ciclo diesel utilizando diesel e misturas de biodiesel Comparative performance of a cycle diesel engine using diesel and biodiesel mixtures

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Ronald Leite Barbosa

2008-10-01

Full Text Available Os atuais elevados preços do barril de petróleo no mercado internacional, a possibilidade de geração de postos de trabalho e renda com a conseqüente fixação do homem no campo, as excelentes e variadas condições climáticas e os tipos de relevo fazem com que o Brasil, com suas extensas áreas agricultáveis, destaque-se no cenário mundial em relação à sua grande potencialidade de geração de combustíveis alternativos. A situação ambiental faz com que o ser humano trabalhe no desenvolvimento de alternativas energéticas, destacando-se aquelas oriundas de fontes renováveis e biodegradáveis de caráter eminentemente sustentável. Assim, objetivou-se com este trabalho avaliar o desempenho de um motor ciclo diesel, funcionando em momentos distintos com diesel mineral e misturas deste com biodiesel nas proporções equivalentes a B2 (98% de diesel mineral e 2% de biodiesel, B5 (95% de diesel mineral e 5% de biodiesel, B20 (80% de diesel mineral e 20% de biodiesel e B100 (100% de biodiesel. Para a realização dos ensaios, foi utilizado um motor ciclo diesel de um trator VALMET 85 id, de 58,2kW (78 cv, de acordo com metodologia estabelecida pela norma NBR 5484 da ABNT (1985 que se refere ao ensaio dinamométrico de motores de ciclo Otto e Diesel. Concluiu-se que a potência do motor ao se utilizar biodiesel foi inferior àquela quando se utilizou diesel mineral. Observou-se que, em algumas rotações, as misturas B5 e B20 apresentaram potência igual ou até superior, em algumas situações, àquela quando se utilizou diesel mineral. A melhor eficiência térmica do motor foi verificada na rotação de 540 rpm da TDP equivalente a 1720 rpm do motor.It is considered that, in a close future, the petroleum reservations economically viable will tend to the shortage. Besides it, the exacerbated current price levels of the petroleum barrel in the international market, the possibility of employment generation and income with the consequent

Determinações simultaneas de acidos em misturas por titulações potenciometricas e suas aplicações a analises de antiacidos, sucos de uva e vinhos

OpenAIRE

Nilson Evelazio Souza

1985-01-01

Resumo: Os vários métodos matemáticos e gráficos usados no tratamento dos dados de titulações potenciométricas são discutidos. Um método algébrico linear foi utilizado na deterninação de várias misturas sintéticas visando a aplicação em matrizes reais. Foram estudadas as determinações simultâneas dos ácidos em várias misturas dos ácidos clorídrico, tartárico, málico, succínico e cítrico. Os valores de pKa destes ácidos foram determinados em meio 1,0 M de NaNO3, tendo em vista o ajuste de forç...

Herbal extracts and symbiotic mixture replacing antibiotics in piglets at the initial phase Extratos herbais e mistura simbiótica em substituição aos antibióticos para suínos na fase inicial

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Márcio Gilberto Zangeronimo

2011-05-01

peso inicial de 7,4 ± 1,1 kg, desmamados aos 20 dias, durante 50 dias. O delineamento experimental foi o de blocos casualizados (peso inicial com cinco tratamentos e cinco repetições com cinco animais por unidade experimental. As dietas experimentais foram uma ração basal, sem aditivo, e outras quatro, uma contendo antibiótico (colistina + óxido de zinco; outra com 0,3% de uma mistura simbiótica; outra com 0,3% da mistura simbiótica e 0,05% de uma mistura herbal (extrato de plantas e óleos essenciais microencapsulados e outra com 0,3% da mistura simbiótica e 0,10% da mistura herbal. Foi observado que o uso da mistura simbiótica associada a 0,05% da mistura herbal teve resultados positivos e semelhantes aos obtidos com as dietas contendo antibióticos quanto ao peso final, ganho de peso, consumo médio diário, pH do estômago e incidência de diarreia. O uso de simbióticos promoveu menor relação vilosidade:cripta, exceto quando associado a 0,1% da mistura herbal, que se assemelhou à dieta sem aditivos. Não houve diferenças na conversão alimentar, na contagem de coliformes e lactobacilus no jejuno e no ceco e no pH do ceco. O uso de uma mistura herbal associada a simbióticos é uma alternativa viável para substituição ao uso de antibióticos como promotores de crescimento para suínos na fase inicial. No entanto, a concentração da mistura herbal é um fator importante a ser considerado.

Gravitational microlensing by low-mass objects in the globular cluster M22.

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Sahu, K C; Casertano, S; Livio, M; Gilliland, R L; Panagia, N; Albrow, M D; Potter, M

2001-06-28

Gravitational microlensing offers a means of determining directly the masses of objects ranging from planets to stars, provided that the distances and motions of the lenses and sources can be determined. A globular cluster observed against the dense stellar field of the Galactic bulge presents ideal conditions for such observations because the probability of lensing is high and the distances and kinematics of the lenses and sources are well constrained. The abundance of low-mass objects in a globular cluster is of particular interest, because it may be representative of the very early stages of star formation in the Universe, and therefore indicative of the amount of dark baryonic matter in such clusters. Here we report a microlensing event associated with the globular cluster M22. We determine the mass of the lens to be 0.13(+0.03)(-0.02) solar masses. We have also detected six events that are unresolved in time. If these are also microlensing events, they imply that a non-negligible fraction of the cluster mass resides in the form of free-floating planetary-mass objects.

The Luminosity Functions of Old and Intermediate-Age Globular Clusters in NGC 3610

OpenAIRE

Whitmore, B. C.; Schweizer, F.; Kundu, A.; Miller, B. W.

2002-01-01

The WFPC2 Camera on board HST has been used to obtain high-resolution images of NGC 3610, a dynamically young elliptical galaxy. These observations supersede shorter, undithered HST observations where an intermediate-age population of globular clusters was first discovered. The new observations show the bimodal color distribution of globular clusters more clearly, with peaks at (V-I)o = 0.95 and 1.17. The luminosity function (LF) of the blue, metal-poor population of clusters in NGC 3610 turn...

Trazando la materia oscura con cúmulos globulares

Science.gov (United States)

Forte, J. C.

Se describe la estrategia adoptada para mapear la distribución de materia oscura y bariónica en galaxias elípticas cuyos cúmulos globulares están siendo observados con los telescopios VLT y Gemini. Se ejemplifican los resultados con los datos obtenidos en el cúmulo de Fornax.

Dating the Tidal Disruption of Globular Clusters with GAIA Data on Their Stellar Streams

Science.gov (United States)

Bose, Sownak; Ginsburg, Idan; Loeb, Abraham

2018-05-01

The Gaia mission promises to deliver precision astrometry at an unprecedented level, heralding a new era for discerning the kinematic and spatial coordinates of stars in our Galaxy. Here, we present a new technique for estimating the age of tidally disrupted globular cluster streams using the proper motions and parallaxes of tracer stars. We evolve the collisional dynamics of globular clusters within the evolving potential of a Milky Way-like halo extracted from a cosmological ΛCDM simulation and analyze the resultant streams as they would be observed by Gaia. The simulations sample a variety of globular cluster orbits, and account for stellar evolution and the gravitational influence of the disk of the Milky Way. We show that a characteristic timescale, obtained from the dispersion of the proper motions and parallaxes of stars within the stream, is a good indicator for the time elapsed since the stream has been freely expanding away due to the tidal disruption of the globular cluster. This timescale, in turn, places a lower limit on the age of the cluster. The age can be deduced from astrometry using a modest number of stars, with the error on this estimate depending on the proximity of the stream and the number of tracer stars used.

Remoção da cor no tratamento combinado de lixiviado de aterro sanitário e esgoto doméstico via processo PACT®

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Ángel Santiago Fernández Bou

2018-03-01

Full Text Available RESUMO Misturas diferentes de lixiviado de aterro sanitário e esgoto doméstico foram aplicadas em 16 reatores em batelada usando o processo PACT® (lodos ativados com adição de carvão ativado em pó - CAP. O objetivo do trabalho foi representar a remoção de cor utilizando dois ajustes matemáticos: o primeiro combinou as variáveis concentração de CAP (0 a 6 g.L-1 e mistura lixiviado/esgoto (0 a 10%, em volume; e o segundo, a concentração de CAP e a cor da mistura (276 a 1.199 uH. A metodologia de superfície de resposta (MSR foi escolhida para representar a resposta dos ajustes. Os resultados indicaram que, conforme a concentração de lixiviado aumentou até 5%, a adição de CAP resultou em um maior percentual de remoção de cor. No entanto, para a mistura com 10% de lixiviado, os reatores perderam eficácia, com exceção do reator com 6 g.L-1 de CAP, que apresentou os melhores resultados de remoção de cor.

Misturas de herbicidas para o controle de plantas daninhas anuais na cultura de citrus (Citrus sinensis (L. Osbeck Herbicides mixtures for the control of annual weeds in citrus crop (Citrus sinensis (L, Osbeck

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A.J.B. Galli

1985-12-01

Full Text Available Com o objetivo de se avaliar a eficiência das misturas de glyphosate com diuron ou simazine para o controle de plantas daninhas anuais na cultura de citrus, foram conduzidos dois experimentos durante o ano agrícola 83/84, sendo um em Jaguariúna e outro em Catanduva, ambos no estado de São Paulo. Os resultados obtidos mostraram que, embora todos os tratamentos tenham sido altamente eficientes, o controle de Digitaria horizontalis, Brachiaria plantaginea e portulaca oleracea aos 10 DAT foi um pouco inferior quando se aplicou as misturas de tanque (glyphosate + diuron ou simazine, em relação à aplicação seqüencial desses mesmos produtos. A adição do sulfato de amônio nas misturas de tanque minimizou esse problema, o qual não foi observado na avaliação realizada aos 30 DAT. Ainda com relação às misturas, o controle das gramíneas foi superior quando se utilizou diuron em relação à simazine. As misturas de herbicidas residuais com glyphosate proporcionaram melhor controle aos 60 DAT quando comparados às aplicações de glyphosate isoladamente.With the aim of evaluating the efficiency of glyphosate mixtures with diuron and simazine, in the control of annual weeds in citrus, two experiments were conducted in Catanduva and Jaguariúna, SP, during the 83/84 season. The results showed high efficiency of all treatments, but the control of Digitaria horizontalis, Brachiaria plantaginea and Portulaca oleracea at 10 DAT, has been slightly inferior when tank mistures were applied, in contrast with the sequencial application of these products. The addition of ammonium sulphate to the tank mixtures minimized the problem which was not observed at 30 DAT. Concerning mixtures, grass control was better with diuron than simazine. The use of glyphosate in mixtures with residuals offered better control at 60 DAT when compared to Glyphosate alone.

Comportamento de espécies herbáceas em misturas de solo com diferentes graus de contaminação com metais pesados

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Carneiro Marco Aurélio Carbone

2002-01-01

Full Text Available O objetivo deste trabalho foi avaliar, em casa de vegetação, o comportamento de espécies herbáceas em relação ao excesso de Cd e Zn no solo. O gradiente de contaminação foi estabelecido a partir de mistura de solo contaminado com solo sem contaminação em diferentes proporções. As sementes foram semeadas em tubetes contendo 250 mL de solo, e após 90 dias as plantas foram colhidas e avaliadas. A maioria das espécies apresentou redução no crescimento com aumento da contaminação do solo e elevadas concentrações de Cd e Zn na matéria seca da parte aérea (MSPA, na mistura com 15% de solo contaminado. A espécie Pffafia sp. mostrou-se tolerante à contaminação, crescendo em misturas de solo contendo até 90 mg kg-1 de Cd e 1.450 mg kg-1 de zinco. Além disso, apresentou concentração superior a 100 mg kg-1 de Cd na MSPA, sendo considerada hiperacumuladora desse metal. Sida glaziovii, Bidens pilosa, Rhynchelytrum repens, Cenchrus echinatus e Nicandra physaloides, por sua vez, foram severamente afetadas pela contaminação, ao contrário de Trifolium repens, Euchlaena mexicana, Cynodon dactylon, Avena strigosa, Cenchrus ciliares e Cyperus sp. que apresentaram crescimento satisfatório. As espécies avaliadas mostram-se promissoras para estudos adicionais sobre a reabilitação de áreas contaminadas com metais pesados.

TIME-SERIES PHOTOMETRY OF GLOBULAR CLUSTERS: M62 (NGC 6266), THE MOST RR LYRAE-RICH GLOBULAR CLUSTER IN THE GALAXY?

International Nuclear Information System (INIS)

Contreras, R.; Catelan, M.; Smith, H. A.; Kuehn, C. A.; Pritzl, B. J.; Borissova, J.

2010-01-01

We present new time-series CCD photometry, in the B and V bands, for the moderately metal-rich ([Fe/H] ≅ -1.3) Galactic globular cluster M62 (NGC 6266). The present data set is the largest obtained so far for this cluster and consists of 168 images per filter, obtained with the Warsaw 1.3 m telescope at the Las Campanas Observatory and the 1.3 m telescope of the Cerro Tololo Inter-American Observatory, in two separate runs over the time span of 3 months. The procedure adopted to detect the variable stars was the optimal image subtraction method (ISIS v2.2), as implemented by Alard. The photometry was performed using both ISIS and Stetson's DAOPHOT/ALLFRAME package. We have identified 245 variable stars in the cluster fields that have been analyzed so far, of which 179 are new discoveries. Of these variables, 133 are fundamental mode RR Lyrae stars (RRab), 76 are first overtone (RRc) pulsators, 4 are type II Cepheids, 25 are long-period variables (LPVs), 1 is an eclipsing binary, and 6 are not yet well classified. Such a large number of RR Lyrae stars places M62 among the top two most RR Lyrae-rich (in the sense of total number of RR Lyrae stars present) globular clusters known in the Galaxy, second only to M3 (NGC 5272) with a total of 230 known RR Lyrae stars. Since this study covers most but not all of the cluster area, it is not unlikely that M62 is in fact the most RR Lyrae-rich globular cluster in the Galaxy. In like vein, thanks to the time coverage of our data sets, we were also able to detect the largest sample of LPVs known so far in a Galactic globular cluster. We analyze a variety of Oosterhoff type indicators for the cluster, including mean periods, period distribution, Bailey diagrams, and Fourier decomposition parameters (as well as the physical parameters derived therefrom). All of these indicators clearly show that M62 is an Oosterhoff type I system. This is in good agreement with the moderately high metallicity of the cluster, in spite of its

Close stellar encounters in globular clusters

International Nuclear Information System (INIS)

Bailyn, C.D.

1989-01-01

Stellar encounters are expected to produce a variety of interesting objects in the cores of globular clusters, either through the formation of binaries by tidal capture, or direct collisions. Here, I describe several attempts to observe the products of stellar encounters. In particular, the use of color maps has demonstrated the existence of a color gradient in the core of M15, which seems to be caused by a population of faint blue objects concentrated towards the cluster center. (author)

Color Gradients Within Globular Clusters: Restricted Numerical Simulation

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Young-Jong Sohn

1997-06-01

Full Text Available The results of a restricted numerical simulation for the color gradients within globular clusters have been presented. The standard luminosity function of M3 and Salpeter's initial mass functions were used to generate model clusters as a fundamental population. Color gradients with the sample clusters for both King and power law cusp models of surface brightness distributions are discussed in the case of using the standard luminosity function. The dependence of color gradients on several parameters for the simulations with Salpeter's initial mass functions, such as slope of initial mass functions, cluster ages, metallicities, concentration parameters of King model, and slopes of power law, are also discussed. No significant radial color gradients are shown to the sample clusters which are regenerated by a random number generation technique with various parameters in both of King and power law cusp models of surface brightness distributions. Dynamical mass segregation and stellar evolution of horizontal branch stars and blue stragglers should be included for the general case of model simulations to show the observed radial color gradients within globular clusters.

Simulação tridimensional adaptativa da separação das fases de uma mistura bifásica usando a equação de Cahn-Hilliard

OpenAIRE

Nós, R.L.; Ceniceros, H.D.; Roma, A.M.

2012-01-01

Simulamos a separação dos componentes de uma mistura bifásica com a equação de Cahn-Hilliard. Esta equação contém intrincados termos não lineares e derivadas de alta ordem. Além disso, a delgada região de transição entre os componentes da mistura requer muita resolução. Assim, determinar a solução numérica da equação de Cahn-Hilliard não é uma tarefa fácil, principalmente em três dimensões. Conseguimos a resolução exigida no tempo usando uma discretização semi-implícita de segunda ordem. No e...

Comportamento de blocos cerâmicos estruturais produzidos a partir da mistura de lama vermelha e argila

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Alcebíades Negrão Macêdo

Full Text Available A utilização de novas técnicas de aproveitamento de resíduos tem-se tornado cada vez mais importante na construção civil, principalmente quando se trata da utilização de resíduos de outros segmentos industriais e da redução de consumo de matérias-primas naturais. O objetivo deste estudo foi avaliar a utilização da lama vermelha, resíduo proveniente da produção de alumina metalúrgica, na produção de blocos cerâmicos vazados estruturais. A produção dos blocos foi realizada em uma indústria cerâmica, a partir de uma mistura de 60% de lama vermelha (LV e de 40% de argila. Após a produção dos blocos, realizaram-se ensaios de acordo com as normas técnicas, tais como absorção de água e compressão axial simples. A partir da análise dos resultados, observou-se que os blocos estruturais produzidos a partir da mistura de LV e argila atenderam aos parâmetros normativos quanto ao índice de absorção de água e de resistência à compressão, e que as resistências médias e características desses blocos foram superiores às dos blocos cerâmicos de referência.

The structure of the Myo4p globular tail and its function in ASH1 mRNA localization.

Science.gov (United States)

Heuck, Alexander; Fetka, Ingrid; Brewer, Daniel N; Hüls, Daniela; Munson, Mary; Jansen, Ralf-Peter; Niessing, Dierk

2010-05-03

Type V myosin (MyoV)-dependent transport of cargo is an essential process in eukaryotes. Studies on yeast and vertebrate MyoV showed that their globular tails mediate binding to the cargo complexes. In Saccharomyces cerevisiae, the MyoV motor Myo4p interacts with She3p to localize asymmetric synthesis of HO 1 (ASH1) mRNA into the bud of dividing cells. A recent study showed that localization of GFP-MS2-tethered ASH1 particles does not require the Myo4p globular tail, challenging the supposed role of this domain. We assessed ASH1 mRNA and Myo4p distribution more directly and found that their localization is impaired in cells expressing globular tail-lacking Myo4p. In vitro studies further show that the globular tail together with a more N-terminal linker region is required for efficient She3p binding. We also determined the x-ray structure of the Myo4p globular tail and identify a conserved surface patch important for She3p binding. The structure shows pronounced similarities to membrane-tethering complexes and indicates that Myo4p may not undergo auto-inhibition of its motor domain.

The fragmentation of proto-globular clusters. I. Thermal instabilities

International Nuclear Information System (INIS)

Murray, S.D.; Lin, D.N.C.

1989-01-01

The metal abundances among the stars within a typical globular cluster are remarkably homogeneous. This indicates that star formation in these systems was a globally coordinated event which occurred over a time span less than or comparable to the collapse time scale of the cluster. This issue is addressed by assuming that the fragmentation of a proto-globular cluster cloud proceeded in two steps. In the first step, thermal instability led to the rapid growth of initial fluctuations. This led to a large contrast in the dynamical time scales between the perturbations and the parent cloud, and the perturbations then underwent gravitational instabilities on short time scales. This process is modeled using one-dimensional hydrodynamic simulations of clouds both with and without external heat sources and self-gravity. The models include the effects of a non-equilibrium H2 abundance. The results indicate that fragmentation can occur on time scales significantly less than the dynamical time scale of the parent cloud. 21 refs

Globular hepatic amyloid is highly sensitive and specific for LECT2 amyloidosis.

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Chandan, Vishal S; Shah, Sejal S; Lam-Himlin, Dora M; Petris, Giovanni De; Mereuta, Oana M; Dogan, Ahmet; Torbenson, Michael S; Wu, Tsung-Teh

2015-04-01

Globular hepatic amyloid (GHA) is rare, and its clinical significance remains unclear. Recently, leukocyte chemotactic factor-associated amyloidosis (ALECT2) has been reported to involve the liver, showing a globular pattern. We reviewed 70 consecutive cases of hepatic amyloidosis to determine the prevalence and morphology of hepatic amyloid subtypes, especially ALECT2 and its association with GHA. Each case was reviewed for amyloid subtype (immunohistochemistry and/or mass spectrometry), its pattern (linear or globular), and distribution (vascular, perisinusoidal, or stromal). In addition, 24 cases of confirmed hepatic ALECT2 on mass spectrometry from our consultation files were also reviewed. LECT2 immunostaining was performed in 49 cases. Of the 70 cases, immunoglobulin light chain (AL) type was most common with 41 cases (59%), followed by transthyretin (ATTR) 15 cases (22%), 3 cases each of fibrinogen A (AFib) (4%), serum amyloid A (AA) (4%), and ALECT2 (4%), 2 cases of apolipoproteins (AApoA1) (3%), and 3 cases (4%) were unclassified. Three of our 70 cases (4%), with ALECT2, and all 24 cases (100%) of mass spectrometry-confirmed hepatic ALECT2 showed only GHA deposits in the hepatic sinusoids and portal tracts. Three (4%) other cases of AL type showed a focal globular pattern admixed with prominent linear amyloid. None of the other amyloid subtypes showed GHA. LECT2 immunostain was positive in all 27 cases (100%) of ALECT2 and negative in the other 22 non-ALECT2 cases (100%) (14 AL, 5 ATTR, 1 AA, 1 AFib, 1 AApoA1). Pure GHA is uncommon (4%) but is highly specific for ALECT2, and LECT2 immunostain is helpful in confirming this amyloid type.

Globular Cluster Variable Stars—Atlas and Coordinate Improvement using AAVSOnet Telescopes (Abstract)

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Welch, D.; Henden, A.; Bell, T.; Suen, C.; Fare, I.; Sills, A.

2015-12-01

(Abstract only) The variable stars of globular clusters have played and continue to play a significant role in our understanding of certain classes of variable stars. Since all stars associated with a cluster have the same age, metallicity, distance and usually very similar (if not identical reddenings), such variables can produce uniquely powerful constraints on where certain types of pulsation behaviors are excited. Advanced amateur astronomers are increasingly well-positioned to provide long-term CCD monitoring of globular cluster variable star but are hampered by a long history of poor or inaccessible finder charts and coordinates. Many of variable-rich clusters have published photographic finder charts taken in relatively poor seeing with blue-sensitive photographic plates. While useful signal-to-noise ratios are relatively straightforward to achieve for RR Lyrae, Type 2 Cepheids, and red giant variables, correct identification remains a difficult issue—particularly when images are taken at V or longer wavelengths. We describe the project and report its progress using the OC61, TMO61, and SRO telescopes of AAVSOnet after the first year of image acquisition and demonstrate several of the data products being developed for globular cluster variables.

Parâmetros astrofísicos de estrelas gigantes do aglomerado globular 47 Tucanae

Science.gov (United States)

Alves-Brito, A.; Barbuy, B.

2003-08-01

Os aglomerados globulares são considerados laboratórios astrofísicos para a verificação da teoria de evolução estelar, bem como a trajetória químio-dinâmica das galáxias hospedeiras. Em particular, 47 Tucanae (NGC 104) configura-se como um dos mais extensivamente estudados aglomerados globulares da Galáxia devido a relativa proximidade ao Sol (R¤ = 4.5 kpc) e alta latitute galáctica (b = -44°,89). Neste trabalho, apresentamos a velocidade radial heliocêntrica e os parâmetros atmosféricos (Teff, logg, [Fe/H]) de 5 estrelas gigantes do aglomerado globular 47 Tucanae. Os espectros foram obtidos pelo espectrógrafo UVES (Ultaviolet Visual Echelle Spectrograph) de alta resolução (R = 60000) e alta razão sinal-ruído (S/N > 200), acoplado ao telescópio de 8,2m Kueyen do VLT (Very Large Telescope). Nós encontramos = -22,43 +/- 3,97 km/s, [Fe/H] ~ -0.7, 1,2 estrelas cobrem um intervalo de magnitude 12,2 < V < 14,2. Os parâmetros atmosféricos são fundamentais para a construção de espectros sintéticos de outros aglomerados globulares ricos em metais. Trabalho financiado pela FAPESP e pelo CNPq.

Evidence from stellar abundances for a large age difference between two globular clusters

International Nuclear Information System (INIS)

Dickens, R.J.; Croke, B.F.W.; Cannon, R.D.; Bell, R.A.

1991-01-01

The globular clusters NGC288 and NGC362 are central to recent claims of large age differences (∼3 Gyr) between globular clusters associated with our Galaxy. According to standard models for the formation of the Galaxy, the system of globular clusters formed during the dynamical collapse of the protogalactic cloud, a process which should have lasted no more than 1 Gyr. But the claimed age differences are derived from stellar evolution models using assumed CNO abundances, and uncertainty in the actual CNO abundances of about a factor of three could account for an apparent 2-Gyr age difference. We have accurately measured abundances in red giants in NGC288 and NGC362, and find that the Fe abundance and the sum of the C, N and O abundances are essentially the same in every star studied. By eliminating compositional differences and thus confirming the reality of the age difference, these results imply a cluster formation period that is hard to reconcile with the standard collapse model. (author)

Efeito da ordem de adição de componentes nas propriedades de misturas NR/BR Properties of NR/BR mixtures and their dependence on the preparation mode

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Daniele F. Castro

2007-03-01

Full Text Available Misturas de elastômeros vêm sendo largamente utilizadas na indústria de borracha com a finalidade de se conseguir propriedades específicas, sem a necessidade de sintetizar novos polímeros. O polibutadieno puro (BR não apresenta boas características de processamento e de resistência à tração e ao rasgamento sendo, por essa razão, normalmente utilizado em misturas com outros elastômeros, principalmente NR e SBR. Tais misturas são amplamente utilizadas na indústria de pneus. Neste trabalho o polibutadieno (BR foi misturado à borracha natural (NR na proporção de 1:1 em peso. As composições foram preparadas em misturador de cilindros, empregando-se quatro maneiras distintas de incorporação dos aditivos. Após a vulcanização, foram estudadas as propriedades mecânicas (resistência à tração, ao rasgamento e dureza e a morfologia das composições. Os resultados mostram que, apesar de apresentarem a mesma formulação, as propriedades das misturas são bastante influenciadas pelo modo de preparo.Elastomer Blends have been widely used in the rubber industry with the purpose of reaching specific properties without the need of synthesizing new polymers. Polybutadiene rubber (BR presents poor stress and tear strengths, which is the main reason why BR is usually blended with NR and SBR. These blends are extensively used in the manufacture of tyres. In this work natural rubber (NR was mixed to polybutadiene rubber (BR in a 50:50 w/w ratio. The compositions were prepared in a two-roll mill employing four different modes of introducing the additives. After vulcanization, the mixtures were studied with evaluation of their mechanical (stress and tear strengths and hardness properties and morphology. The results show that the properties varied even using the same NR/BR formulations due to the different preparation techniques.

The SLUGGS survey: globular cluster stellar population trends from weak absorption lines in stacked spectra

Science.gov (United States)

Usher, Christopher; Forbes, Duncan A.; Brodie, Jean P.; Romanowsky, Aaron J.; Strader, Jay; Conroy, Charlie; Foster, Caroline; Pastorello, Nicola; Pota, Vincenzo; Arnold, Jacob A.

2015-01-01

As part of the SAGES Legacy Unifying Globulars and GalaxieS (SLUGGS) survey, we stack 1137 Keck DEIMOS (Deep Imaging Multi-Object Spectrograph) spectra of globular clusters from 10 galaxies to study their stellar populations in detail. The stacked spectra have median signal-to-noise ratios of ˜90 Å-1. Besides the calcium triplet, we study weaker sodium, magnesium, titanium and iron lines as well as the Hα and higher order Paschen hydrogen lines. In general, the stacked spectra are consistent with old ages and a Milky Way-like initial mass function. However, we see different metal line index strengths at fixed colour and magnitude, and differences in the calcium triplet-colour relation from galaxy to galaxy. We interpret this as strong evidence for variations in the globular cluster colour-metallicity relation between galaxies. Two possible explanations for the colour-metallicity relation variations are that the average ages of globular clusters vary from galaxy to galaxy or that the average abundances of light elements (i.e. He, C, N and O) differ between galaxies. Stacking spectra by magnitude, we see that the colours become redder and metal line indices stronger with brighter magnitudes. These trends are consistent with the previously reported `blue tilts' being mass-metallicity relations.

Structure and Dynamics of the Globular Cluster Palomar 13

Science.gov (United States)

Bradford, J. D.; Geha, M.; Muñoz, R. R.; Santana, F. A.; Simon, J. D.; Côté, P.; Stetson, P. B.; Kirby, E.; Djorgovski, S. G.

2011-12-01

We present Keck/DEIMOS spectroscopy and Canada-France-Hawaii Telescope/MegaCam photometry for the Milky Way globular cluster Palomar 13. We triple the number of spectroscopically confirmed members, including many repeat velocity measurements. Palomar 13 is the only known globular cluster with possible evidence for dark matter, based on a Keck/High Resolution Echelle Spectrometer 21 star velocity dispersion of σ = 2.2 ± 0.4 km s-1. We reproduce this measurement, but demonstrate that it is inflated by unresolved binary stars. For our sample of 61 stars, the velocity dispersion is σ = 0.7+0.6 -0.5 km s-1. Combining our DEIMOS data with literature values, our final velocity dispersion is σ = 0.4+0.4 -0.3 km s-1. We determine a spectroscopic metallicity of [Fe/H] = -1.6 ± 0.1 dex, placing a 1σ upper limit of σ[Fe/H] ~ 0.2 dex on any internal metallicity spread. We determine Palomar 13's total luminosity to be MV = -2.8 ± 0.4, making it among the least luminous known globular clusters. The photometric isophotes are regular out to the half-light radius and mildly irregular outside this radius. The outer surface brightness profile slope is shallower than typical globular clusters (Σvpropr η, η = -2.8 ± 0.3). Thus at large radius, tidal debris is likely affecting the appearance of Palomar 13. Combining our luminosity with the intrinsic velocity dispersion, we find a dynamical mass of M 1/2 = 1.3+2: 7 -1.3 × 103 M ⊙ and a mass-to-light ratio of M/LV = 2.4+5.0 -2.4 M ⊙/L ⊙. Within our measurement errors, the mass-to-light ratio agrees with the theoretical predictions for a single stellar population. We conclude that, while there is some evidence for tidal stripping at large radius, the dynamical mass of Palomar 13 is consistent with its stellar mass and neither significant dark matter, nor extreme tidal heating, is required to explain the cluster dynamics. The data presented herein were obtained at the W. M. Keck Observatory, which is operated as a

The SUMO project I. A survey of multiple populations in globular clusters

Science.gov (United States)

Monelli, M.; Milone, A. P.; Stetson, P. B.; Marino, A. F.; Cassisi, S.; del Pino Molina, A.; Salaris, M.; Aparicio, A.; Asplund, M.; Grundahl, F.; Piotto, G.; Weiss, A.; Carrera, R.; Cebrián, M.; Murabito, S.; Pietrinferni, A.; Sbordone, L.

2013-05-01

We present a general overview and the first results of the SUMO project (a SUrvey of Multiple pOpulations in Globular Clusters). The objective of this survey is the study of multiple stellar populations in the largest sample of globular clusters homogeneously analysed to date. To this aim we obtained high signal-to-noise (S/N > 50) photometry for main sequence stars with mass down to ˜0.5 M⊙ in a large sample of clusters using both archival and proprietary U, B, V and I data from ground-based telescopes. In this paper, we focus on the occurrence of multiple stellar populations in 23 clusters. We define a new photometric index, cU, B, I = (U - B) - (B - I), which turns out to be very effective for identifying multiple sequences along the red giant branch (RGB). We found that in the V-cU, B, I diagram all clusters presented in this paper show broadened or multimodal RGBs, with the presence of two or more components. We found a direct connection with the chemical properties of different sequences, which display different abundances of light elements (O, Na, C, N and Al). The cU, B, I index is also a powerful tool for identifying distinct sequences of stars along the horizontal branch and, for the first time in the case of NGC 104 (47 Tuc), along the asymptotic giant branch. Our results demonstrate that (i) the presence of more than two stellar populations is a common feature amongst globular clusters, as already highlighted in previous work; (ii) multiple sequences with different chemical contents can be easily identified by using standard Johnson photometry obtained with ground-based facilities; (iii) in the study of globular cluster multiple stellar populations the cU, B, I index is an alternative to spectroscopy, and has the advantage of larger statistics.

Análises físico-químicas de pré-misturas de pães de queijo e produção de pães de queijo com adição de okara Physicochemical analyses of commercial samples of cheese bread premix and production of cheese breads with addition of okara

Directory of Open Access Journals (Sweden)

Krischina Singer Aplevicz

2007-10-01

Full Text Available Okara, ou resíduo de soja, é um subproduto do processamento do extrato aquoso de soja e do tofu. Pão de queijo é um produto assado ao forno obtido a partir da mistura de polvilho com água ou leite, queijo, sal e gordura, podendo ser utilizados polvilho doce, azedo ou a mistura deles. Objetivou-se com este trabalho caracterizar pré-misturas comerciais de pão de queijo por intermédio de análises físico-químicas e também avaliar a qualidade de pães de queijo produzidos com a adição de subproduto da obtenção do extrato aquoso de soja. As características de qualidade de pães de queijo suplementados com 5, 10 e 15% de okara foram investigadas. Os pães de queijo suplementados com subproduto okara apresentaram teores de proteínas e de fibras alimentares superiores ao controle. Os produtos panificados foram submetidos à análise sensorial de aceitabilidade utilizando-se a escala hedônica de nove pontos, com provadores não-treinados. Amostras de pães de queijo com 5, 10 e 15% de okara não foram consideradas diferentes significativamente em nível de 5% e tiveram boa aceitação.Okara, or soy residue, is a byproduct of soy aqueous extract and tofu manufacturing. Cheese bread is a Brazilian specialty made by blending cassava starch (cassava starch or sour cassava starch water or milk, cheese, salt and fat and is baked on oven. This study has the objective of characterizing cheese breads made with addition of okara. Additionally in this work commercial samples of cheese bread premix were compared in terms of physicochemical properties. The quality characteristics of cheese breads supplemented with 5, 10 and 15% of okara were investigated. The results showed that the cheese breads supplemented with the byproduct okara had an increase in the protein and dietary fiber contents. The samples were submitted to an acceptability sensory evaluation with a nine point hedonic scale, involving untrained panelists. The cheese breads made with 5

[Study of beta-turns in globular proteins].

Science.gov (United States)

Amirova, S R; Milchevskiĭ, Iu V; Filatov, I V; Esipova, N G; Tumanian, V G

2005-01-01

The formation of beta-turns in globular proteins has been studied by the method of molecular mechanics. Statistical method of discriminant analysis was applied to calculate energy components and sequences of oligopeptide segments, and after this prediction of I type beta-turns has been drawn. The accuracy of true positive prediction is 65%. Components of conformational energy considerably affecting beta-turn formation were delineated. There are torsional energy, energy of hydrogen bonds, and van der Waals energy.

A NEW DISTANT MILKY WAY GLOBULAR CLUSTER IN THE PAN-STARRS1 3π SURVEY

International Nuclear Information System (INIS)

Laevens, Benjamin P. M.; Martin, Nicolas F.; Sesar, Branimir; Rix, Hans-Walter; Schlafly, Edward F.; Bernard, Edouard J.; Ferguson, Annette M. N.; Slater, Colin T.; Bell, Eric F.; Burgett, William S.; Chambers, Kenneth C.; Denneau, Larry; Kaiser, Nicholas; Kudritzki, Rolf-Peter; Magnier, Eugene A.; Morgan, Jeffrey S.; Sweeney, William E.; Draper, Peter W.; Metcalfe, Nigel; Price, Paul A.

2014-01-01

We present a new satellite in the outer halo of the Galaxy, the first Milky Way satellite found in the stacked photometric catalog of the Panoramic Survey Telescope and Rapid Response System 1 (Pan-STARRS1) Survey. From follow-up photometry obtained with WFI on the MPG/ESO 2.2 m telescope, we argue that the object, located at a heliocentric distance of 145 ± 17 kpc, is the most distant Milky Way globular cluster yet known. With a total magnitude of M V = –4.3 ± 0.2 and a half-light radius of 20 ± 2 pc, it shares the properties of extended globular clusters found in the outer halo of our Galaxy and the Andromeda galaxy. The discovery of this distant cluster shows that the full spatial extent of the Milky Way globular cluster system has not yet been fully explored

NO EVIDENCE FOR INTERMEDIATE-MASS BLACK HOLES IN GLOBULAR CLUSTERS: STRONG CONSTRAINTS FROM THE JVLA

International Nuclear Information System (INIS)

Strader, Jay; Chomiuk, Laura; Maccarone, Thomas J.; Miller-Jones, James C. A.; Seth, Anil C.; Heinke, Craig O.; Sivakoff, Gregory R.

2012-01-01

With a goal of searching for accreting intermediate-mass black holes (IMBHs), we report the results of ultra-deep Jansky Very Large Array radio continuum observations of the cores of three Galactic globular clusters: M15, M19, and M22. We reach rms noise levels of 1.5-2.1 μJy beam –1 at an average frequency of 6 GHz. No sources are observed at the center of any of the clusters. For a conservative set of assumptions about the properties of the accretion, we set 3σ upper limits on IMBHs from 360 to 980 M ☉ . These limits are among the most stringent obtained for any globular cluster. They add to a growing body of work that suggests either (1) IMBHs ∼> 1000 M ☉ are rare in globular clusters or (2) when present, IMBHs accrete in an extraordinarily inefficient manner.

No Evidence for Intermediate-mass Black Holes in Globular Clusters: Strong Constraints from the JVLA

Science.gov (United States)

Strader, Jay; Chomiuk, Laura; Maccarone, Thomas J.; Miller-Jones, James C. A.; Seth, Anil C.; Heinke, Craig O.; Sivakoff, Gregory R.

2012-05-01

With a goal of searching for accreting intermediate-mass black holes (IMBHs), we report the results of ultra-deep Jansky Very Large Array radio continuum observations of the cores of three Galactic globular clusters: M15, M19, and M22. We reach rms noise levels of 1.5-2.1 μJy beam-1 at an average frequency of 6 GHz. No sources are observed at the center of any of the clusters. For a conservative set of assumptions about the properties of the accretion, we set 3σ upper limits on IMBHs from 360 to 980 M ⊙. These limits are among the most stringent obtained for any globular cluster. They add to a growing body of work that suggests either (1) IMBHs >~ 1000 M ⊙ are rare in globular clusters or (2) when present, IMBHs accrete in an extraordinarily inefficient manner.

ANÁLISE DA CORRELAÇÃO ENTRE AS VARIÁVEIS DE DENSIFICAÇÃO DO COMPACTADOR GIRATÓRIO SUPERPAVE E A RESISTÊNCIA À DEFORMAÇÃO PERMANENTE EM MISTURAS ASFÁLTICAS CONVENCIONAIS E COM UTILIZAÇÃO DE RESÍDUOS

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Felipe Coutinho Onofre

2011-09-01

Full Text Available

Quando se comparam as metodologias de dosagem Superpave e Marshall de misturas asfálticas, uma das vantagens da primeira é a obtenção do gráfico de compactação. Tem sido verificado para misturas densas e contínuas do tipo Concreto Asfáltico (CA que determinadas áreas observadas nesse gráfico podem diferenciar estas misturas quanto à trabalhabilidade e à resistência à deformação permanente. No presente estudo, os parâmetros Compaction Densification Index (CDI e Traffic Densification Index (TDI foram utilizados como indicadores da compactabilidade. Desenvolveu-se um estudo de correlação entre estas variáveis e a resistência à deformação permanente de misturas asfálticas. Foram avaliadas três misturas asfálticas contendo: (i apenas agregados graníticos, (ii 50% de agregados graníticos e 50% de escória de aciaria e (iii 50% de agregados graníticos e 50% de Resíduo de Construção e Demolição (RCD. As variáveis escolhidas para determinação da resistência à deformação permanente foram o ensaio uniaxial de carga repetida (amostras compactadas para dois percentuais de Volume de vazios e o ensaio com um simulador de tráfego do tipo LCPC. Foi utilizado também o Processamento Digital de Imagens (PDI para a determinação da esfericidade dos agregados estudados, propriedade que influencia na resistência à deformação permanente. Os resultados indicam que as variáveis CDI e TDI podem ser usadas como parâmetros de estudo para prever a resistência à deformação permanente, mesmo para misturas com utilização de resíduos. A caracterização pela técnica do PDI mostrou que o agregado de origem granítica possui uma forma menos próxima a uma esfera em relação aos res

An AO-assisted Variability Study of Four Globular Clusters

Science.gov (United States)

Salinas, R.; Contreras Ramos, R.; Strader, J.; Hakala, P.; Catelan, M.; Peacock, M. B.; Simunovic, M.

2016-09-01

The image-subtraction technique applied to study variable stars in globular clusters represented a leap in the number of new detections, with the drawback that many of these new light curves could not be transformed to magnitudes due to severe crowding. In this paper, we present observations of four Galactic globular clusters, M 2 (NGC 7089), M 10 (NGC 6254), M 80 (NGC 6093), and NGC 1261, taken with the ground-layer adaptive optics module at the SOAR Telescope, SAM. We show that the higher image quality provided by SAM allows for the calibration of the light curves of the great majority of the variables near the cores of these clusters as well as the detection of new variables, even in clusters where image-subtraction searches were already conducted. We report the discovery of 15 new variables in M 2 (12 RR Lyrae stars and 3 SX Phe stars), 12 new variables in M 10 (11 SX Phe and 1 long-period variable), and 1 new W UMa-type variable in NGC 1261. No new detections are found in M 80, but previous uncertain detections are confirmed and the corresponding light curves are calibrated into magnitudes. Additionally, based on the number of detected variables and new Hubble Space Telescope/UVIS photometry, we revisit a previous suggestion that M 80 may be the globular cluster with the richest population of blue stragglers in our Galaxy. Based on observations obtained at the Southern Astrophysical Research (SOAR) telescope, which is a joint project of the Ministério da Ciência, Tecnologia, e Inovação (MCTI) da República Federativa do Brasil, the U.S. National Optical Astronomy Observatory (NOAO), the University of North Carolina at Chapel Hill (UNC), and Michigan State University (MSU).

BVRI CCD photometry of the globular cluster NGC 2808

International Nuclear Information System (INIS)

Alcaino, G.; Liller, W.; Alvarado, F.; Wenderoth, E.

1990-01-01

As a part of a continuing program, CCD color-magnitude diagrams are presented for the bright globular cluster NGC 2808 in the four colors comprising BVRI. From a comparison of four different CMDs with theoretical isochrones, an age of 16 + or - 2 Gyr is obtained, assuming a value for Fe/H near -1.3. 28 refs

A variabilidade química da plagioclase no plutonito de Reguengos de Monsaraz (OMZ): testemunhos de mistura de magmas

OpenAIRE

Antunes, A.; Santos, J. F.; Azevedo, M. R.

2010-01-01

Os dados de química mineral obtidos em plagioclases dos diferentes tipos litológicos presentes no plutonito de Reguengos de Monsaraz (gabro-dioritos, tonalitos e granodioritos) mostram que os cristais de maiores dimensões são caracterizados por uma grande diversidade de padrões de zonamento (normal, oscilatório e complexo) e um espectro composicional variando de bytownite a andesina (An83 a An40), o que parece reflectir os efeitos de processos de mistura de magmas. Em contrapartida, a variabi...

From Globular Clusters to Tidal Dwarfs: Structure Formation in Tidal Tails

Science.gov (United States)

Knierman, K.; Hunsberger, S.; Gallagher, S.; Charlton, J.; Whitmore, B.; Hibbard, J.; Kundu, A.; Zaritsky, D.

1999-12-01

Galaxy interactions trigger star formation in tidal debris. How does this star formation depend on the local and global physical conditions? Using WFPC2/HST images, we investigate the range of structure within tidal tails of four classic ``Toomre Sequence'' mergers: NGC 4038/9 (``Antennae''), NGC 7252 (``Atoms for Peace''), NGC 3921, and NGC 3256. These tails contain a variety of stellar associations with sizes from globular clusters up to dwarf Irregulars. We explore whether there is a continuum between the two extremes. Our eight fields sample seven tidal tails at a variety of stages in the evolutionary sequence. Some of these tails are rich in HI while others are HI poor. Large tidal dwarfs are embedded in three of the tails. Using V and I WFPC2 images, we measure luminosities and colors of substructures within the tidal tails. The properties of globular cluster candidates in the tails will be contrasted with those of the hundreds of young clusters in the central regions of these mergers. We address whether globular clusters form and survive in the tidal tails and whether tidal dwarfs are composed of only young stars. By comparing the properties of structures in the tails of the four mergers with different ages, we examine systematic evolution of structure along the evolutionary sequence and as a function of HI content. We acknowledge support from NASA through STScI, and from NSF for an REU supplement for Karen Knierman.

Structural insights into the globular tails of the human type v myosins Myo5a, Myo5b, And Myo5c.

Directory of Open Access Journals (Sweden)

Hana Velvarska

Full Text Available Vertebrate type V myosins (MyoV Myo5a, Myo5b, and Myo5c mediate transport of several different cargoes. All MyoV paralogs bind to cargo complexes mainly by their C-terminal globular domains. In absence of cargo, the globular domain of Myo5a inhibits its motor domain. Here, we report low-resolution SAXS models for the globular domains from human Myo5a, Myo5b, and Myo5c, which suggest very similar overall shapes of all three paralogs. We determined the crystal structures of globular domains from Myo5a and Myo5b, and provide a homology model for human Myo5c. When we docked the Myo5a crystal structure into a previously published electron microscopy density of the autoinhibited full-length Myo5a, only one domain orientation resulted in a good fit. This structural arrangement suggests the participation of additional region of the globular domain in autoinhibition. Quantification of the interaction of the Myo5a globular domain with its motor complex revealed a tight binding with dissociation half-life in the order of minutes, suggesting a rather slow transition between the active and inactive states.

Chemical analysis of eight giant stars of the globular cluster NGC 6366

Science.gov (United States)

Puls, Arthur A.; Alves-Brito, Alan; Campos, Fabíola; Dias, Bruno; Barbuy, Beatriz

2018-05-01

The metal-rich Galactic globular cluster NGC 6366 is the fifth closest to the Sun. Despite its interest, it has received scarce attention, and little is known about its internal structure. Its kinematics suggests a link to the halo, but its metallicity indicates otherwise. We present a detailed chemical analysis of eight giant stars of NGC 6366, using high-resolution and high-quality spectra (R > 40 000, S/N > 60) obtained at the VLT (8.2 m) and CFHT (3.6 m) telescopes. We attempted to characterize its chemistry and to search for evidence of multiple stellar populations. The atmospheric parameters were derived using the method of excitation and ionization equilibrium of Fe I and Fe II lines and from those atmospheric parameters we calculated the abundances for other elements and found that none of the elements measured presents star-to-star variation greater than the uncertainties. We compared the derived abundances with those of other globular clusters and field stars available in the literature. We determined a mean [Fe/H] = -0.60 ± 0.03 for NGC 6366 and found some similarity of this object with M 71, another inner halo globular cluster. The Na-O anticorrelation extension is short and no star-to-star variation in Al is found. The presence of second generation stars is not evident in NGC 6366.

Hydrophobicity diversity in globular and nonglobular proteins measured with the Gini index.

Science.gov (United States)

Carugo, Oliviero

2017-12-01

Amino acids and their properties are variably distributed in proteins and different compositions determine all protein features, ranging from solubility to stability and functionality. Gini index, a tool to estimate distribution uniformity, is widely used in macroeconomics and has numerous statistical applications. Here, Gini index is used to analyze the distribution of hydrophobicity in proteins and to compare hydrophobicity distribution in globular and intrinsically disordered proteins. Based on the analysis of carefully selected high-quality data sets of proteins extracted from the Protein Data Bank (http://www.rcsb.org) and from the DisProt database (http://www.disprot.org/), it is observed that hydrophobicity is distributed in a more diverse way in intrinsically disordered proteins than in folded and soluble globular proteins. This correlates with the observation that the amino acid composition deviates from the uniformity (estimate with the Shannon and the Gini-Simpson indices) more in intrinsically disordered proteins than in globular and soluble proteins. Although statistical tools tike the Gini index have received little attention in molecular biology, these results show that they allow one to estimate sequence diversity and that they are useful to delineate trends that can hardly be described, otherwise, in simple and concise ways. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

THE IMPACT OF CONTAMINATED RR LYRAE/GLOBULAR CLUSTER PHOTOMETRY ON THE DISTANCE SCALE

Energy Technology Data Exchange (ETDEWEB)

Majaess, D.; Turner, D.; Lane, D. [Department of Astronomy and Physics, Saint Mary' s University, Halifax, NS B3H 3C3 (Canada); Gieren, W., E-mail: dmajaess@ap.smu.ca [Departamento de Astronomia, Universidad de Concepcion, Casilla 160-C, CL Concepcion (Chile)

2012-06-10

RR Lyrae variables and the stellar constituents of globular clusters are employed to establish the cosmic distance scale and age of the universe. However, photometry for RR Lyrae variables in the globular clusters M3, M15, M54, M92, NGC 2419, and NGC 6441 exhibit a dependence on the clustercentric distance. For example, variables and stars positioned near the crowded high-surface brightness cores of the clusters may suffer from photometric contamination, which invariably affects a suite of inferred parameters (e.g., distance, color excess, absolute magnitude, etc.). The impetus for this study is to mitigate the propagation of systematic uncertainties by increasing awareness of the pernicious impact of contaminated and radial-dependent photometry.

Dimensionamento do eixo do impelidor em sistemas de agitação e mistura para processos industriais

OpenAIRE

Eduardo Jose Barbosa

2004-01-01

Resumo: O objetivo deste trabalho é desenvolver uma metodologia de cálculo, de uso simples, porém de caráter robusto, a ser utilizado na seleção de sistemas de agitação e mistura, que englobam: Cálculo/dimensionamento do eixo do agitador para torção e flexão tipo "eixo vazado" para conjunto unico e de multiplos impelidores; Verificação da Rotação Crítica para sistemas de agitação que possuem eixos em balanço; Estimar a potência consumi da em sistemas agitados que utilizam impelidor( es) para ...

M31 GLOBULAR CLUSTER STRUCTURES AND THE PRESENCE OF X-RAY BINARIES

International Nuclear Information System (INIS)

Agar, J. R. R.; Barmby, P.

2013-01-01

The Andromeda galaxy, M31, has several times the number of globular clusters found in the Milky Way. It contains a correspondingly larger number of low-mass X-ray binaries (LMXBs) associated with globular clusters, and as such can be used to investigate the cluster properties that lead to X-ray binary formation. The best tracer of the spatial structure of M31 globulars is the high-resolution imaging available from the Hubble Space Telescope (HST), and we have used HST data to derive structural parameters for 29 LMXB-hosting M31 globular clusters. These measurements are combined with structural parameters from the literature for a total of 41 (of 50 known) LMXB clusters and a comparison sample of 65 non-LMXB clusters. Structural parameters measured in blue bandpasses are found to be slightly different (smaller core radii and higher concentrations) than those measured in red bandpasses; this difference is enhanced in LMXB clusters and could be related to stellar population differences. Clusters with LMXBs show higher collision rates for their mass compared to clusters without LMXBs, and collision rates estimated at the core radius show larger offsets than rates estimated at the half-light radius. These results are consistent with the dynamical formation scenario for LMXBs. A logistic regression analysis finds that, as expected, the probability of a cluster hosting an LMXB increases with increasing collision rate and proximity to the galaxy center. The same analysis finds that probability of a cluster hosting an LMXB decreases with increasing cluster mass at a fixed collision rate, although we caution that this could be due to sample selection effects. Metallicity is found to be a less important predictor of LMXB probability than collision rate, mass, or distance, even though LMXB clusters have a higher metallicity on average. This may be due to the interaction of location and metallicity: a sample of M31 LMXBs with a greater range in galactocentric distance would

LITHIUM-RICH GIANTS IN GLOBULAR CLUSTERS

Energy Technology Data Exchange (ETDEWEB)

Kirby, Evan N.; Cohen, Judith G. [California Institute of Technology, 1200 E. California Boulevard, MC 249-17, Pasadena, CA 91125 (United States); Guhathakurta, Puragra [UCO/Lick Observatory and Department of Astronomy and Astrophysics, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States); Zhang, Andrew J. [The Harker School, 500 Saratoga Avenue, San Jose, CA 95129 (United States); Hong, Jerry [Palo Alto High School, 50 Embarcadero Road, Palo Alto, CA, 94301 (United States); Guo, Michelle [Stanford University, 450 Serra Mall, Stanford, CA 94305 (United States); Guo, Rachel [Irvington High School, 41800 Blacow Road, Fremont, CA 94538 (United States); Cunha, Katia [Observatório Nacional, São Cristóvão Rio de Janeiro (Brazil)

2016-03-10

Although red giants deplete lithium on their surfaces, some giants are Li-rich. Intermediate-mass asymptotic giant branch (AGB) stars can generate Li through the Cameron–Fowler conveyor, but the existence of Li-rich, low-mass red giant branch (RGB) stars is puzzling. Globular clusters are the best sites to examine this phenomenon because it is straightforward to determine membership in the cluster and to identify the evolutionary state of each star. In 72 hours of Keck/DEIMOS exposures in 25 clusters, we found four Li-rich RGB and two Li-rich AGB stars. There were 1696 RGB and 125 AGB stars with measurements or upper limits consistent with normal abundances of Li. Hence, the frequency of Li-richness in globular clusters is (0.2 ± 0.1)% for the RGB, (1.6 ± 1.1)% for the AGB, and (0.3 ± 0.1)% for all giants. Because the Li-rich RGB stars are on the lower RGB, Li self-generation mechanisms proposed to occur at the luminosity function bump or He core flash cannot explain these four lower RGB stars. We propose the following origin for Li enrichment: (1) All luminous giants experience a brief phase of Li enrichment at the He core flash. (2) All post-RGB stars with binary companions on the lower RGB will engage in mass transfer. This scenario predicts that 0.1% of lower RGB stars will appear Li-rich due to mass transfer from a recently Li-enhanced companion. This frequency is at the lower end of our confidence interval.

The deposition of globular polypyrrole and polypyrrole nanotubes on cotton textile

Czech Academy of Sciences Publication Activity Database

Bober, Patrycja; Stejskal, Jaroslav; Šeděnková, Ivana; Trchová, Miroslava; Martinková, L.; Marek, J.

2015-01-01

Roč. 356, 30 November (2015), s. 737-741 ISSN 0169-4332 R&D Projects: GA TA ČR(CZ) TE01020022 Institutional support: RVO:61389013 Keywords : conducting textile * cotton * globular polypyrrole Subject RIV: CG - Electrochemistry Impact factor: 3.150, year: 2015

Deep CCD photometry in globular clusters III. M15

International Nuclear Information System (INIS)

Fahlman, G.G.; Richer, H.B.; Vandenberg, D.A.

1985-01-01

CCD photometry in U, B, and V is presented for a 5' x 3' field in the globular cluster M15. The location of the main sequence in the color-magnitude diagram is found here to be significantly bluer than previous studies have indicated. The luminosity function of the cluster is studied down to V = 22.8 (Mroughly-equal7.5) and shown to be consistent with a power-law mass function, n(M) = QM/sup -alpha/ with α = 2.5 +- 1.0, to the limit of our data. The field star population brighter than V = 21.5, is examined in some detail. There appears to be about 50% more stars belonging to the disk in the field as compared with the Bahcall-Soneira standard galaxy model. The reddening to the cluster is found to be E(B-V) = 0.11 +- 0.04 from nine bright field stars. A new value for the ultraviolet excess of the cluster main-sequence stars is obtained, delta(0.6) = 0.25 +- 0.02, and confirms the well-known fact that M15 is among the metal poorest of the globular clusters

An Archival Search For Young Globular Clusters in Galaxies

Science.gov (United States)

Whitmore, Brad

1995-07-01

One of the most intriguing results from HST has been the discovery of ultraluminous star clusters in interacting and merging galaxies. These clusters have the luminosities, colors, and sizes that would be expected of young globular clusters produced by the interaction. We propose to use the data in the HST Archive to determine how prevalent this phenomena is, and to determine whether similar clusters are produced in other environments. Three samples will be extracted and studied in a systematic and consistent manner: 1} interacting and merging galaxies, 2} starburst galaxies, 3} a control sample of ``normal'' galaxies. A preliminary search of the archives shows that there are at least 20 galaxies in each of these samples, and the number will grow by about 50 observations become available. The data will be used to determine the luminosity function, color histogram , spatial distribution, and structural properties of the clusters using the same techniques employed in our study of NGC 7252 {``Atoms -for-Peace'' galaxy} and NGC 4038/4039 {``The Antennae''}. Our ultimate goals are: 1} to understand how globular clusters form, and 2} to use the clusters as evolutionary tracers to unravel the histories of interacting galaxies.

Deep radio synthesis images of globular clusters

International Nuclear Information System (INIS)

Kulkarni, S.R.; Goss, W.M.; Wolszczan, A.; Middleditch, J.

1990-01-01

Results are reported from a program of high-resolution and high-sensitivity imaging of globular clusters at 20 cm. The findings indicate that there is not a large number of pulsars in compact binaries which have escaped detection in single-dish pulse searches. Such binaries have been postulated to result from tidal captures of single main-sequence stars. It is suggested that most tidal captures involving neutron stars ultimately result in the formation of a spun-up single pulsar and the complete disruption of the main-sequence star. 27 refs

Variable Stars in Large Magellanic Cloud Globular Clusters. II. NGC 1786

Science.gov (United States)

Kuehn, Charles A.; Smith, Horace A.; Catelan, Márcio; Pritzl, Barton J.; De Lee, Nathan; Borissova, Jura

2012-12-01

This is the second in a series of papers studying the variable stars in Large Magellanic Cloud globular clusters. The primary goal of this series is to study how RR Lyrae stars in Oosterhoff-intermediate systems compare to their counterparts in Oosterhoff I/II systems. In this paper, we present the results of our new time-series B-V photometric study of the globular cluster NGC 1786. A total of 65 variable stars were identified in our field of view. These variables include 53 RR Lyraes (27 RRab, 18 RRc, and 8 RRd), 3 classical Cepheids, 1 Type II Cepheid, 1 Anomalous Cepheid, 2 eclipsing binaries, 3 Delta Scuti/SX Phoenicis variables, and 2 variables of undetermined type. Photometric parameters for these variables are presented. We present physical properties for some of the RR Lyrae stars, derived from Fourier analysis of their light curves. We discuss several different indicators of Oosterhoff type which indicate that the Oosterhoff classification of NGC 1786 is not as clear cut as what is seen in most globular clusters. Based on observations taken with the SMARTS 1.3 m telescope operated by the SMARTS Consortium and observations taken at the Southern Astrophysical Research (SOAR) telescope, which is a joint project of the Ministério da Ciência, Tecnologia, e Inovação (MCTI) da República Federativa do Brasil, the U.S. National Optical Astronomy Observatory (NOAO), the University of North Carolina at Chapel Hill (UNC), and Michigan State University (MSU).

The "Globularization Hypothesis" of the Language-ready Brain as a Developmental Frame for Prosodic Bootstrapping Theories of Language Acquisition.

Science.gov (United States)

Irurtzun, Aritz

2015-01-01

In recent research (Boeckx and Benítez-Burraco, 2014a,b) have advanced the hypothesis that our species-specific language-ready brain should be understood as the outcome of developmental changes that occurred in our species after the split from Neanderthals-Denisovans, which resulted in a more globular braincase configuration in comparison to our closest relatives, who had elongated endocasts. According to these authors, the development of a globular brain is an essential ingredient for the language faculty and in particular, it is the centrality occupied by the thalamus in a globular brain that allows its modulatory or regulatory role, essential for syntactico-semantic computations. Their hypothesis is that the syntactico-semantic capacities arise in humans as a consequence of a process of globularization, which significantly takes place postnatally (cf. Neubauer et al., 2010). In this paper, I show that Boeckx and Benítez-Burraco's hypothesis makes an interesting developmental prediction regarding the path of language acquisition: it teases apart the onset of phonological acquisition and the onset of syntactic acquisition (the latter starting significantly later, after globularization). I argue that this hypothesis provides a developmental rationale for the prosodic bootstrapping hypothesis of language acquisition (cf. i.a. Gleitman and Wanner, 1982; Mehler et al., 1988, et seq.; Gervain and Werker, 2013), which claim that prosodic cues are employed for syntactic parsing. The literature converges in the observation that a large amount of such prosodic cues (in particular, rhythmic cues) are already acquired before the completion of the globularization phase, which paves the way for the premises of the prosodic bootstrapping hypothesis, allowing babies to have a rich knowledge of the prosody of their target language before they can start parsing the primary linguistic data syntactically.

The globularization hypothesis of the language-ready brain as a developmental frame for prosodic bootstrapping theories of language acquisition

Directory of Open Access Journals (Sweden)

Aritz eIrurtzun

2015-12-01

Full Text Available In recent research Boeckx & Benítez-Burraco (2014a,b have advanced the hypothesis that our species-specific language-ready brain should be understood as the outcome of developmental changes that occurred in our species after the split from Neanderthals-Denisovans, which resulted in a more globular braincase configuration in comparison to our closest relatives, who had elongated endocasts. According to these authors, the development of a globular brain is an essential ingredient for the language faculty and in particular, it is the centrality occupied by the thalamus in a globular brain that allows its modulatory or regulatory role, essential for syntactico-semantic computations. Their hypothesis is that the syntactico-semantic capacities arise in humans as a consequence of a process of globularization, which significantly takes place postnatally (cf. Neubauer et al. (2010. In this paper, I show that Boeckx & Benítez-Burraco’s hypothesis makes an interesting developmental prediction regarding the path of language acquisition: it teases apart the onset of phonological acquisition and the onset of syntactic acquisition (the latter starting significantly later, after globularization. I argue that this hypothesis provides a developmental rationale for the prosodic bootstrapping hypothesis of language acquisition (cf. i.a. Gleitman & Wanner (1982; Mehler et al. (1988, et seq.; Gervain & Werker (2013, which claim that prosodic cues are employed for syntactic parsing. The literature converges in the observation that a large amount of such prosodic cues (in particular, rhythmic cues are already acquired before the completion of the globularization phase, which paves the way for the premises of prosodic bootstrapping hypothesis, allowing babies to have a rich knowledge of the prosody of their target language before they can start parsing the primary linguistic data syntactically.

Formulações e mistura de glyphosate sobre endossimbioses e o desempenho agronômico da soja Roundup Ready®

OpenAIRE

Gonçalves, Clebson Gomes

2014-01-01

Objetivou-se avaliar o efeito de diferentes formulações comerciais de glyphosate e os efeitos do glyphosate isolado e em mistura com chlorimuron-ethyl, flumioxazin e lactofen sobre microrganismos endossimbiontes e sobre o desempenho agronômico de soja resistente ao glyphosate. Para as diferentes formulações, instalaram-se experimentos a campo nos anos agrícolas 2010/2011 e 2011/2012. Os tratamentos constituíram-se da aplicação das formulações sal de isopropilamina (Roundup Original, Trop); sa...

Most Massive Globular Cluster in Our Galaxy

Science.gov (United States)

1994-05-01

Far down in the southern sky, in the constellation of Centaurus, a diffuse spot of light can be perceived with the unaided eye. It may be unimpressive, but when seen through a telescope, it turns out to be a beautiful, dense cluster of innumerable stars [1]. Omega Centauri, as this object is called, is the brightest of its type in the sky. We refer to it as a "globular cluster", due to its symmetric form. It belongs to our Milky Way galaxy and astrophysical investigations have shown that it is located at a distance of about 16,500 light-years (1 light-year = 9,460,000,000,000 km). Nobody knows for sure how many individual stars it contains, but recent estimates run into the millions. Most of these stars are more than 10,000 million years old and it is generally agreed that Omega Centauri has a similar age. Measurements of its motion indicate that Omega Centauri plows through the Milky Way in an elongated orbit. It is not easy to understand how it has managed to keep its stars together during such an extended period. MEASURING STELLAR VELOCITIES IN OMEGA CENTAURI A group of astronomers [2] have recently carried through a major investigation of Omega Centauri. After many nights of observations at the ESO La Silla observatory, they now conclude that not only is this globular cluster the brightest, it is indeed by far the most massive known in the Milky Way. The very time-consuming observations were made during numerous observing sessions over a period of no less than 13 years (1981-1993), with the photoelectric spectrometer CORAVEL mounted on the 1.5-m Danish telescope at La Silla. The CORAVEL instrument (COrelation RAdial VELocities) was built in a joint effort between the Geneva (Switzerland) and Marseilles (France) observatories. It functions according to the cross-correlation technique, by means of which the spectrum of the observed star is compared with a "standard stellar spectrum" [3]. HOW HEAVY IS OMEGA CENTAURI? In the present study, a total of 1701

BVRI main-sequence photometry of the globular cluster M4

International Nuclear Information System (INIS)

Alcaino, G.; Liller, W.

1984-01-01

We present BV and RI photographic photometry of 1421 and 189 stars, respectively, in the intermediate metallicity globular cluster M4 (NGC 6121). This investigation includes the first results of RI main-sequence photometry of a globular cluster. The use of longer wavelengths and longer color baselines provides the potential of improved isochrone fittings and underscores the urgent need for calculations of RI synthetic isochrones to be compared with observations. The Pickering-Racine wedge was used with the ESO 3.6 m telescope, the Las Campanas 2.5 m du Pont telescope, and the CTIO 1 m Yale telescope to extend the photoelectric limit from Vroughly-equal16.1 to Vroughly-equal19.1. We have determined the position of the main-sequence turnoff to lie at V = 16.6 +- 0.2 (m.e.) and B-V = 0.80 +- 0.03 (m.e.). A comparison of our BV observations with the CCD data of Richer and Fahlman shows excellent agreement: the two fifucial main sequences agree at all points to within 0.025 mag and, on average, to 0.013 mag. For the cluster we derive a distance modulus (m-M)/sub V/ = 12.52 +- 0.2 and reddening E(B-V) = 0.44 +- 0.03, results which confirm that at a distance of 2 kpc, M4 is the closest globular clusters to the Sun. Using the isochrones of VandenBerg, we deduce an age 13 +- 2 Gyr. As noted in several other investigations, there is a striking deficiency of stars in certain parts of the color-magnitude diagram; in M4 we find a pronounced gap over approx.0.6 mag at the base of the subgiant branch

USO DA EQUAÇÃO DE ESTADO DE PENG-ROBINSON COM REGRA DE MISTURA DEPENDENTE DA COMPOSIÇÃO NA PREDIÇÃO DO EQUILÍBRIO DE FASES DO SISTEMA TERNÁRIO CO2-LIMONENO-CITRAL

Directory of Open Access Journals (Sweden)

Alessandra Lopes de OLIVEIRA

1997-12-01

Full Text Available Dados de equilíbrio de fases a pressões elevadas dos sistemas binários CO2-Limoneno e CO2-Citral e do sistema ternário CO2-Limoneno-Citral foram coletados da literatura e usados na modelagem termodinâmica que emprega a equação de estado de PENG-ROBINSON [1] com: 1 Regra de mistura clássica; 2 Regra de mistura dependente da composição de STRYJEK & VERA [2]. Os parâmetros de interação binária entre CO2-Limoneno e CO2-Citral foram obtidos pelo ajuste dos modelos a dados experimentais, fazendo uso de dois programas computacionais, os quais envolvem a minimização de uma função objetivo, pelo método Simplex de NELDER & MEAD (3, que foi escrita em termos dos desvios relativos entre os pontos experimentais e os calculados pelos modelos. O equilíbrio de fases do sistema ternário foi calculado utilizando-se os parâmetros de interação binária ajustados previamente e considerando parâmetros nulos entre os componentes Limoneno e Citral. A análise dos resultados indica, para as condições supercríticas, que os dois modelos foram capazes de predizer qualitativamente o sistema ternário, fornecendo resultados compatíveis, em ordem de grandeza, com os valores experimentais.Phase equilibrium data at high pressures for CO2-Limonene and CO2-Citral binary systems and for CO2-Limonene-Citral ternary systems were collected from literature and employed in a thermodynamic modelling that uses the PENG-ROBINSON equation of state with: (1 classical mixture rule; (2 STRYJEK & VERA composition dependant mixture rule. The binary interaction parameters for the CO2-Limonene and CO2-Citral systems were obtained by fitting the models to the experimental data using two computational programmes that involved the minimisation of an objective function by the simplex method as suggested by NELDER & MEAD, written as a function of the deviation between experimental and calculated data. The phase equilibrium for the ternary systems was calculated using the

A period-luminosity relation for Mira variables in globular clusters and its impact on the distance scale

International Nuclear Information System (INIS)

Menzies, J.W.; Whitelock, P.A.

1985-01-01

JHKL photometry is presented for 31 red variables in 15 galactic globular clusters. The photometry of the Mira variables is used to find absolute bolometric magnitudes and an Msub(bol)-log P relation which differs from the one found for LMC Miras. This can be understood only if there is some systematic error in the globular cluster and/or LMC distance scales or if there is some fundamental difference between the cluster Miras and those in the LMC. (author)

Electrorheological properties of suspensions of hollow globular titanium oxide/polypyrrole particles

Czech Academy of Sciences Publication Activity Database

Sedlačík, M.; Mrlík, M.; Pavlínek, V.; Sáha, P.; Quadrat, Otakar

2012-01-01

Roč. 290, č. 1 (2012), s. 41-48 ISSN 0303-402X R&D Projects: GA ČR GA202/09/1626 Institutional research plan: CEZ:AV0Z40500505 Keywords : electrorheology * titanium oxide * hollow globular clusters Subject RIV: JI - Composite Materials Impact factor: 2.161, year: 2012

Tracing dust in old stellar populations : the mid-infrared spectrum of globular cluster AGB stars

International Nuclear Information System (INIS)

Richter, H.

2010-01-01

Asymptotic Giant Branch (AGB) stars are considered to be the main stellar dust producers in the universe. Their dusty circumstellar shells leave fingerprints in the mid-infrared (MIR) spectra of AGB stars and in unresolved old stellar populations. Bressan et al. (2007) showed that co-added MIR-spectra of AGB stars of known luminosity, metallicity and age (like those found in the Galactic globular cluster NGC104) can be used to model the dust excess in early-type galaxies. This work aims to improve our understanding of the MIR-spectra of old stellar populations with respect to their metallicities by studying a large sample of AGB stars in Galactic globular clusters. A sample of AGB stars (taken from Lebzelter et al. 2006 and Sloan et al. 2010) is used to produce co-added MIR-spectra of globular cluster combinations for three metallicity groups. Each group consists of several globular clusters with similar age and metallicity. Combining the clusters leads to a higher number of AGB stars with available Spitzer spectra in each group. The low metallicity group (Z=0.0038) consists of five globular clusters with 18 AGB star spectra, the intermediate (Z=0.0058) and high (Z=0.01) metallicity groups both include three clusters with eight and seven available MIR-spectra, respectively. Stars within the 90% mass radius of each globular cluster are used to generate 2MASS Color- Magnitude diagrams (CMDs) of each cluster combination. Binning the stars in the CMDs with respect to their MK-values results in Luminosity Functions (LFs) for the cluster combinations. The LFs based on 2MASS data are compared to LFs obtained using theoretical isochrones from the Padova group (Bertelli et al. 2008, Marigo et al. 2008). Using the 2MASS LFs integrated MIR-spectra of the three globular cluster combinations are derived by weighting the existing spectra with the total number of AGB stars within each MK-bin of the LFs along the upper giant branch. This relies on the assumption that stars that

Estudo de misturas asf?lticas com res?duo de constru??o e demoli??o oriundo do munic?pio de Manaus-AM.

OpenAIRE

Melo, Diego Meneses de

2010-01-01

A disserta??o ora apresentada tem por objetivo realizar estudo sobre a utiliza??o de res?duos de constru??es e demoli??es (RCD) como agregado gra?do em concreto asf?ltico, buscando solu??o t?cnica e ambiental para a car?ncia hist?rica de agregados p?treos no munic?pio de Manaus-AM. A pesquisa exp?e caracter?sticas peculiares do material alternativo, comparando com o seixo rolado, elemento usual nas misturas asf?lticas utilizadas regionalmente. Realizouse a dosagem de uma mistur...

Intrachromosomal exchange aberrations predicted on the basis of globular interphase chromosome model

International Nuclear Information System (INIS)

Andreev, S.G.; Eidelman, Yu.A.

2002-01-01

One of the key questions in understanding mechanisms of chromosome aberration production is how does interphase chromosome structure affect aberration formation. To explore this a modelling approach is presented which combines Monte Carlo simulation of both a particle track and interphase chromosome structure. The structural state of interphase chromosome influences a dose-effect relationship for intrachromosomal exchange aberrations (intrachanges). It is shown that intrachanges are induced frequently by both X rays and a particles if the chromosome is in the condensed globular but not in the decondensed coiled state. Truly simple intra-arm intrachanges induced by X rays are dose squared in coiled chromosomes, but exhibit linear dose dependence in globular chromosomes. Experimental data on interarm intrachanges obtained by dual arm chromosome painting are analysed by means of the technique presented. Results of analysis support the conclusion about the arms proximity of chromosome 1 in human lymphocytes. (author)

Properties of the disk system of globular clusters

International Nuclear Information System (INIS)

Armandroff, T.E.

1989-01-01

A large refined data sample is used to study the properties and origin of the disk system of globular clusters. A scale height for the disk cluster system of 800-1500 pc is found which is consistent with scale-height determinations for samples of field stars identified with the Galactic thick disk. A rotational velocity of 193 + or - 29 km/s and a line-of-sight velocity dispersion of 59 + or - 14 km/s have been found for the metal-rich clusters. 70 references

Chemical Abundances of Red Giant Branch Stars in the Globular Clusters NGC 6333 and NGC 6366

Science.gov (United States)

Johnson, Christian I.; Rich, R. M.; Pilachowski, C. A.; Kunder, A. M.

2013-01-01

We present chemical abundances and radial velocities for >20 red giant branch (RGB) stars in the Galactic globular clusters NGC 6333 ([Fe/H]≈-1.8) and NGC 6366 ([Fe/H]≈-0.6). The results are based on moderate resolution (R=18,000), high signal-to-noise ratio (>100) spectra obtained with the Hydra multifiber positioner and bench spectrograph on the WIYN 3.5m telescope at Kitt Peak National Observatory. Both objects are likely associated with the Galactic bulge globular cluster system, and we therefore compare the cluster abundance patterns with those of nearby bulge field stars. Additionally, we investigate differences in the O-Na anticorrelation and neutron-capture element dispersion between the two clusters, and compare their abundance patterns with those of similar metallicity halo globular clusters. This material is based upon work supported by the National Science Foundation under award No. AST-1003201 to C.I.J. C.A.P. gratefully acknowledges support from the Daniel Kirkwood Research Fund at Indiana University. R.M.R. acknowledges support from NSF grant AST-0709479 and AST-121120995.

Chemical Compositions of Stars in the Globular Cluster NGC 3201: Tracers of Multi-Epoch Star Formation

Science.gov (United States)

Simmerer, Jennifer A.; Ivans, I. I.; Filler, D.

2012-01-01

The retrograde halo globular cluster NGC 3201 contains stars of substantially different iron abundance ([Fe/H]), a property that puts it at odds with the vast majority of the Galactic cluster system. Though its unusual orbit prompted speculation that NGC 3201 was the remnant of a captured object, much like the multi-metallicity globular cluster Omega Centauri, NGC 3201 is much less massive than Omega Centauri and all of the other halo globular clusters that have internal metallicity variations. We present the abundances of 21 elements in 24 red giant branch stars in NGC 3201 based on high-resolution (R 40,000), high signal-to-noise (S/N 70) spectra. We find that the detailed abundance pattern of NGC 3201 is unique amongst multi-metallicity halo clusters. Unlike M22, Omega Centauri, and NGC 1851, neither metal-poor nor metal-rich stars show any evidence of s-process enrichment (a product of the advanced evolution of low- and intermediate-mass stars). We find that while Na, O, and Al vary from star to star as is typical in globular clusters, there is no systematic difference between the abundance pattern in the metal-poor cluster stars and that of the metal-rich cluster stars. Furthermore, we find that the metallicity variations in NGC 3201 are independent of the well-known Na-O anticorrelation, which separates it from every other multi-metallicity cluster. In the context of a multi-episode star formation model, this implies that NGC 3201 began life with the [Fe/H] variations we measure now.

Microstructure and rheology of globular protein gels in the presence of gelatin

NARCIS (Netherlands)

Ersch, C.; Meinders, M/B.J.; Bouwman, W.G.; Nieuwland, M.; Linden, E. van der; Venema, P.; Martin, A.H.

2016-01-01

The microstructure and rheological response of globular protein gels (whey protein isolate (WPI) and soy protein isolate (SPI)) in the presence of gelatin (type A, type B and hydrolyzed type A) was investigated. Microstructural information was obtained using a combination of confocal laser scanning

Medium Resolution Spectroscopy and Chemical Composition of Galactic Globular Clusters

Directory of Open Access Journals (Sweden)

Khamidullina D. A.

2014-12-01

Full Text Available We used integrated-light medium-resolution spectra of six Galactic globular clusters and model stellar atmospheres to carry out population synthesis and to derive chemical composition and age of the clusters. We used medium-resolution spectra of globular clusters published by Schiavon et al. (2005, as well as our long-slit observations with the 1.93 m telescope of the Haute Provence Observatory. The observed spectra were fitted to the theoretical ones interactively. As an initial approach, we used masses, radii and log g of stars in the clusters corresponding to the best fitting isochrones in the observed color-magnitude diagrams. The computed synthetic blanketed spectra of stars were summed according to the Chabrier mass function. To improve the determination of age and helium content, the shape and depth of the Balmer absorption lines was analysed. The abundances of Mg, Ca, C and several other elements were derived. A reasonable agreement with the literature data both in chemical composition and in age of the clusters is found. Our method might be useful for the development of stellar population models and for a better understanding of extragalactic star clusters.

The Age of the Inner Halo Globular Cluster NGC 6652

Science.gov (United States)

Chaboyer, Brian; Sarajedini, Ata; Armandroff, Taft E.

2000-01-01

Hubble Space Telescope (HST) (V,I) photometry has been obtained for the inner halo globular cluster NGC 6652. The photometry reaches approximately 4 mag below the turn-off and includes a well populated horizontal branch (HB). This cluster is located close to the Galactic center at RGC approximately equal to 2.0 kpc with a reddening of E(V-I) = 0.15 +/- 0.02 and has a metallicity of [Fe/H] approximately equal to -0.85. Based upon DELTA V (sup SGB) (sub HB), NGC 6652 is 11.7 plus or minus 1.6 Gyr old. Using A HB precise differential ages for 47 Tuc (a thick disk globular), M107 and NGC 1851 (both halo clusters) were obtained. NGC 6652 appears to be the same age as 47 Tuc and NGC 1851 (within +/- 1.2 Gyr), while there is a slight suggestion that M107 is older than NGC 6652 by 2.3 +/- 1.5 Gyr. As this is a less than 2 sigma result, this issue needs to be investigated further before a definitive statement regarding the relative age of M107 and NGC 6652 may be made.

Medium resolution spectroscopy and chemical composition of Galactic globular clusters

Science.gov (United States)

Khamidullina, D. A.; Sharina, M. E.; Shimansky, V. V.; Davoust, E.

We used integrated-light medium-resolution spectra of six Galactic globular clusters and model stellar atmospheres to carry out population synthesis and to derive chemical composition and age of the clusters. We used medium-resolution spectra of globular clusters published by Schiavon et al. (2005), as well as our long-slit observations with the 1.93 m telescope of the Haute Provence Observatory. The observed spectra were fitted to the theoretical ones interactively. As an initial approach, we used masses, radii and log g of stars in the clusters corresponding to the best fitting isochrones in the observed color-magnitude diagrams. The computed synthetic blanketed spectra of stars were summed according to the Chabrier mass function. To improve the determination of age and helium content, the shape and depth of the Balmer absorption lines was analysed. The abundances of Mg, Ca, C and several other elements were derived. A reasonable agreement with the literature data both in chemical composition and in age of the clusters is found. Our method might be useful for the development of stellar population models and for a better understanding of extragalactic star clusters.

Dynamical Friction in Multi-component Evolving Globular Clusters

Science.gov (United States)

Alessandrini, Emiliano; Lanzoni, Barbara; Miocchi, Paolo; Ciotti, Luca; Ferraro, Francesco R.

2014-11-01

We use the Chandrasekhar formalism and direct N-body simulations to study the effect of dynamical friction on a test object only slightly more massive than the field stars, orbiting a spherically symmetric background of particles with a mass spectrum. The main goal is to verify whether the dynamical friction time (t DF) develops a non-monotonic radial dependence that could explain the bimodality of the blue straggler radial distributions observed in globular clusters. In these systems, in fact, relaxation effects lead to a mass and velocity radial segregation of the different mass components, so that mass-spectrum effects on t DF are expected to be dependent on radius. We find that in spite of the presence of different masses, t DF is always a monotonic function of radius, at all evolutionary times and independently of the initial concentration of the simulated cluster. This is because the radial dependence of t DF is largely dominated by the total mass density profile of the background stars (which is monotonically decreasing with radius). Hence, a progressive temporal erosion of the blue straggler star (BSS) population at larger and larger distances from the cluster center remains the simplest and the most likely explanation of the shape of the observed BSS radial distributions, as suggested in previous works. We also confirm the theoretical expectation that approximating a multi-mass globular cluster as made of (averaged) equal-mass stars can lead to significant overestimations of t DF within the half-mass radius.

Constraints from stellar models on mixing as a viable explanation of abundance anomalies in globular clusters

International Nuclear Information System (INIS)

Vandenberg, D.A.; Smith, G.H.

1988-01-01

Published observational data on changes in the surface abundances of evolving stars in globular clusters are compiled and compared with the predictions of theoretical evolutionary sequences (for stars of mass 0.8 solar mass and metallicity Z = 0.0001 or mass 0.9 solar mass and Z = 0.006) and of models incorporating enhanced envelope-interior mixing at various evolutionary phases. The results are presented in graphs and characterized in detail. It is found that mixing models of CN bimodality in globular-cluster stars can encounter difficulties when abundance anomalies appear early in the evolution of the star. 63 references

Globular cluster neutron stars and the determination of the dense matter equation of state

Science.gov (United States)

Guillot, Sebastien

2016-09-01

Combining measurements of the mass and radius of multiple neutron stars (NSs) represents the most promising way to determine the equation of state of dense NS matter. NSs in quiescent low-mass x-ray binaries (qLMXB) located in globular clusters have placed useful constraints on the equation of state. The statistical approaches combining measurements from multiple NSs can be further improved by the addition of more NS observations. We propose here to obtain a high signal to noise spectrum of the qLMXB in M30, the only low-absorption globular cluster qLMXBs that does not have deep X-ray observations, and which requires Chandra unmatched angular resolution. The 300 ks proposed observation will permit measurement of the NS radius with 12-15% uncertainties.

Simulação do comportamento mecânico de misturas asfálticas usando um modelo computacional multi-escala

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Flávio Vasconcelos de Souza

2009-10-01

Full Text Available As misturas asfálticas, por serem materiais heterogêneos, possuem comportamento global dependente do comportamento dos constituintes individuais, de suas frações volumétricas e das interações físico-químicas entre os constituintes, dentre outros fatores. Deste modo, para que se possa compreender melhor o comportamento desses materiais, é necessário o uso de metodologias capazes de considerar as características e fenômenos ocorrentes nas escalas menores. Uma metodologia que vem sendo bastante estudada e aplicada na comunidade científica internacional são os chamados modelos multi-escala. O objetivo do presente trabalho é descrever um modelo computacional multi-escala e aplicá-lo à simulação de ensaios comumente usados em misturas asfálticas, quais sejam, os ensaios de compressão diametral e de fadiga por flexão em viga. Para o caso de compressão diametral, os resultados numéricos se mostraram em concordância com os resultados observados experimentalmente. Para o caso de carregamento cíclico, não foi feita uma comparação com experimentos, mas os resultados numéricos mostram a capacidade do modelo em simular qualitativamente os fenômenos de trincamento por fadiga e acúmulo de deformações permanentes.

Microwave-enhanced folding and denaturation of globular proteins

DEFF Research Database (Denmark)

Bohr, Henrik; Bohr, Jakob

2000-01-01

It is shown that microwave irradiation can affect the kinetics of the folding process of some globular proteins, especially beta-lactoglobulin. At low temperature the folding from the cold denatured phase of the protein is enhanced, while at a higher temperature the denaturation of the protein from...... its folded state is enhanced. In the latter case, a negative temperature gradient is needed for the denaturation process, suggesting that the effects of the microwaves are nonthermal. This supports the notion that coherent topological excitations can exist in proteins. The application of microwaves...

Synthetic properties of models of globular clusters

Energy Technology Data Exchange (ETDEWEB)

Angeletti, L; Dolcetta, R; Giannone, P. (Rome Univ. (Italy). Osservatorio Astronomico)

1980-05-01

Synthetic and projected properties of models of globular clusters have been computed on the basis of stellar evolution and time changes of the dynamical cluster structure. Clusters with five and eight stellar groups (each group consisting of stars with the same mass) were studied. Mass loss from evolved stars was taken into account. Observational features were obtained at ages of 10-19 x 10/sup 9/ yr. The basic importance of the horizontal- and asymptotic-branch stars was pointed out. A comparison of the results with observed data of M3 is discussed with the purpose of obtaining general indications rather than a specific fit.

Synthetic properties of models of globular clusters

International Nuclear Information System (INIS)

Angeletti, L.; Dolcetta, R.; Giannone, P.

1980-01-01

Synthetic and projected properties of models of globular clusters have been computed on the basis of stellar evolution and time changes of the dynamical cluster structure. Clusters with five and eight stellar groups (each group consisting of stars with the same mass) were studied. Mass loss from evolved stars was taken into account. Observational features were obtained at ages of 10-19 x 10 9 yr. The basic importance of the horizontal- and asymptotic-branch stars was pointed out. A comparison of the results with observed data of M3 is discussed with the purpose of obtaining general indications rather than a specific fit. (orig.)

Estudo químico e granulométrico das misturas de fosforita de olinda e apatita do araxá com superfosfato simples Chemical and mechanical study of fosforita de olinda and apatita do araxa mixtures (rock phosphates with ordinary superphosphate

Directory of Open Access Journals (Sweden)

Francisco da Costa Verdade

1960-01-01

Full Text Available Misturas de superfosfato simples, com apatita do Araxá e com fosforita de Olinda, foram estudadas em função do tempo de contato dos componentes e dos teores de P2O5, solúvel em água, ácido cítrico a 2% (Wagner e citrato de amônro. O efeito da moagem, na porcentagem de P2O5 solúvel na água e os índices de pH resultantes das misturas, foram também analisados, bem como a granulometria do material e as variações do seu teor de umidade. Verificou-se que a fosforita de Olinda causa uma insolubilizaçao do P2O5 solúvel em água do superfosfato, quando este adubo participa das misturas nas menores proporções, e que este fenômeno se estabiliza aos 135 dias de contato dos componentes. Aumentando a porcentagem de superfosfato nas misturas, em linhas gerais o fenômeno se desenvolveu de maneira idêntica, não obstante tenha sido verificado aumento de solu-bilidade nas dosagens iniciais. Em todas as misturas com apatita do Araxá, o teor de P(20(5 solúvel em água mostrou-se inicialmente igual ou superior ao teor teórico que deveriam apresentar as misturas, se não ocorresse interação entre seus componentes. Aumentando, porém, o tempo de contato, verificou-se retrogradação crescente desta fração solúvel, sem evidência de estabilização do processo dentro do período de controle da experiência. De um modo geral, o teor de fósforo extraído pelo ácido cítrico, menos a fração solúvel em água das misturas, com ambos os fosfatos naturais cresce com o tempo de contato, inversamente ao que acontece com o P20(5 solúvel em água. A solubilidade das misturas com fosforita em citrato de amônio também aumentou em função do tempo de contato dos componentes, parecendo atingir o ponto de equilíbrio aos 135 dias. Com as misturas de apatita os resultados se mostraram erráticos.Mixtures of ordinary superphosphate with fosforita tie Olinda (sedimentary origin and apatita do Araxá (apatite type were studied by chemical and

Brain asymmetry in the white matter making and globularity

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Constantina eTheofanopoulou

2015-09-01

Full Text Available Recent studies from the field of language genetics and evolutionary anthropology have put forward the hypothesis that the emergence of our species-specific brain is to be understood not in terms of size, but in light of developmental changes that gave rise to a more globular braincase configuration after the split from Neanderthals-Denisovans. On the grounds that (i white matter myelination is delayed relative to other brain structures and in humans is protracted compared with other primates and (ii neural connectivity is linked genetically to our brain/skull morphology and language-ready brain, I take it that one significant evolutionary change in Homo sapiens’ lineage is the interhemispheric connectivity mediated by the Corpus Callosum. The size, myelination and fiber caliber of the Corpus Callosum presents an anterior-to-posterior increase, in a way that inter-hemispheric connectivity is more prominent in the sensory motor areas, whereas high- order areas are more intra-hemispherically connected. Building on evidence from language-processing studies that account for this asymmetry (‘lateralization’ in terms of brain rhythms, I present an evo-devo hypothesis according to which the myelination of the Corpus Callosum, Brain Asymmetry and Globularity are conjectured to make up the angles of a co-evolutionary triangle that gave rise to our language-ready brain.

Study of the spray to globular transition in gas metal arc welding: a spectroscopic investigation

International Nuclear Information System (INIS)

Valensi, F; Pellerin, S; Castillon, Q; Zielinska, S; Boutaghane, A; Dzierzega, K; Pellerin, N; Briand, F

2013-01-01

The gas metal arc welding (GMAW) process is strongly influenced by the composition of the shielding gas. In particular, addition of CO 2 increases the threshold current for the transition from unstable globular to more stable spray transfer mode. We report on the diagnostics—using optical emission spectroscopy—of a GMAW plasma in pure argon and in mixtures of argon, CO 2 and N 2 while operated in spray and globular transfer modes. The spatially resolved plasma parameters are obtained by applying the Abel transformation to laterally integrated emission data. The Stark widths of some iron lines are used to determine both electron density and temperature, and line intensities yield relative contents of neutral and ionized iron to argon. Our experimental results indicate a temperature drop on the arc axis in the case of spray arc transfer. This drop reduces with addition of N 2 and disappears in globular transfer mode when CO 2 is added. Despite the temperature increase, the electron density decreases with CO 2 concentration. The highest concentration of iron is observed in the plasma column upper part (close to the anode) and for GMAW with CO 2 . Our results are compared with recently published works where the effect of non-homogeneous metal vapour concentration has been taken into account. (paper)

Individual globular domains and domain unfolding visualized in overstretched titin molecules with atomic force microscopy.

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Zsolt Mártonfalvi

Full Text Available Titin is a giant elastomeric protein responsible for the generation of passive muscle force. Mechanical force unfolds titin's globular domains, but the exact structure of the overstretched titin molecule is not known. Here we analyzed, by using high-resolution atomic force microscopy, the structure of titin molecules overstretched with receding meniscus. The axial contour of the molecules was interrupted by topographical gaps with a mean width of 27.7 nm that corresponds well to the length of an unfolded globular (immunoglobulin and fibronectin domain. The wide gap-width distribution suggests, however, that additional mechanisms such as partial domain unfolding and the unfolding of neighboring domain multimers may also be present. In the folded regions we resolved globules with an average spacing of 5.9 nm, which is consistent with a titin chain composed globular domains with extended interdomain linker regions. Topographical analysis allowed us to allocate the most distal unfolded titin region to the kinase domain, suggesting that this domain systematically unfolds when the molecule is exposed to overstretching forces. The observations support the prediction that upon the action of stretching forces the N-terminal ß-sheet of the titin kinase unfolds, thus exposing the enzyme's ATP-binding site and hence contributing to the molecule's mechanosensory function.

The properties of the disk system of globular clusters

Science.gov (United States)

Armandroff, Taft E.

1989-01-01

A large refined data sample is used to study the properties and origin of the disk system of globular clusters. A scale height for the disk cluster system of 800-1500 pc is found which is consistent with scale-height determinations for samples of field stars identified with the Galactic thick disk. A rotational velocity of 193 + or - 29 km/s and a line-of-sight velocity dispersion of 59 + or - 14 km/s have been found for the metal-rich clusters.

Photoelectric UBVRI sequences in the Galactic globular clusters NGC 6752 and NGC 6864

International Nuclear Information System (INIS)

Alvarado, F.; Wenderoth, E.; Alcaino, G.; Liller, W.

1990-01-01

UBVRI photoelectric sequences for the Galactic globular clusters NGC 6752 and NGC 6864 are presented. Both of them include fields suitable for CCD exposures. From five UBV sequences in NGC 6572, only five stars are in common with the previous works. 15 refs

Estado de mistura e dispersão da fase borrachosa em blendas PVC/NBR Phase separation and rubber phase dispersion in PVC/NBR blends

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Fábio R. Passador

2006-01-01

Full Text Available Termoplásticos modificados com elastômeros têm despertado grande interesse de pesquisadores e de indústrias devido à atraente relação custo/benefício e a possibilidade de aumento significativo da tenacidade sob impacto de polímeros frágeis com a incorporação de uma fase borrachosa dispersa. Este artigo mostra a relação entre o estado de mistura e a dispersão da fase borrachosa em blendas de poli (cloreto de vinila (PVC com borracha nitrílica (NBR. O estado de mistura de blendas poliméricas é um fator muito importante a ser considerado no desenvolvimento destes tipos de materiais, uma vez que determina o nível de mistura molecular das blendas. A característica estrutural do PVC é responsável pela morfologia das blendas PVC/NBR, sendo que há uma otimização de propriedades mecânicas quando as partículas de borracha formam a morfologia "pseudo-network", ou seja, quando as partículas de borracha estão randomicamente dispersas entre as partículas primárias do PVC.Thermoplastics modified with elastomers have attracted great interest of researchers and industries due to the low cost/benefit relationship and the possibility of significant increase in the toughness of brittle polymers through the incorporation of a dispersed rubber phase. This article shows the relationship between the interaction between phases and rubber phase dispersion in poly (vinyl chloride/nitrile rubber blends. The interaction between components in polymer blends is an important factor to be considered in the development of this kind of materials because it determines the level of the mixture at the molecular level. The particulate nature of PVC and the degree of nitrile groups in the NBR are responsible to the PVC/NBR blends morphologies leading to an optimization of the mechanical properties when the rubber particles form a pseudo-network morphology with the rubber particles randomly dispersed in between the PVC primary particles.

La galaxia NGC 6876 y su sistema de cúmulos globulares

Science.gov (United States)

Ennis, A. I.; Bassino, L. P.; Caso, J. P.

2017-10-01

We present preliminary results of the deep photometric study of the elliptical galaxy NGC6876, located at the center of the Pavo group, and its globular cluster system. We use images obtained with the GMOS camera mounted on the Gemini South telescope, in the and bands, with the purpose of disentangling the evolutionary history of the galaxy on the basis of their characteristics.

Synthetic horizontal branch models for globular clusters - the luminosity of the horizontal branch and the Oosterhoff effect

International Nuclear Information System (INIS)

Lee, Y.W.; Demarque, P.; Zinn, R.

1987-01-01

The variation of horizontal-branch (HB) luminosities with metal abundances is analyzed on the basis of HB models synthesized from theoretical HB evolutionary tracks. The focus is on the Oosterhoff effect, as related to period shifts in globular-cluster RR Lyr variables. The construction of the models and the Oosterhoff period groups is explained in detail, and the implications for globular-cluster ages are considered. The ratio of Delta M(bol) (RR) to Delta Fe/H for the HB is calculated as 0.24, slightly steeper than that found by Sandage (1981 and 1982). 35 references

Comparing Chemical Compositions of Dwarf Elliptical Galaxies and Globular Clusters

Science.gov (United States)

Chu, Jason; Sparkman, Lea; Toloba, Elisa; Guhathakurta, Puragra

2015-01-01

Because of their abundance in cluster environments and fragility due to their low mass, dwarf elliptical galaxies (dEs) are excellent specimens for studying the physical processes that occur inside galaxy clusters. These studies can be used to expand our understanding of the process of galaxy (specifically dE) formation and the role of dark matter in the Universe. To move closer to better understanding these topics, we present a study of the relationship between dEs and globular clusters (GCs) by using the largest sample of dEs and GC satellites to date. We focus on comparing the ages and chemical compositions of dE nuclei with those of satellite GCs by analyzing absorption lines in their spectra. To better view the spectral features of these relatively dim objects, we employ a spectral co-addition process, where we add the fluxes of several objects to produce a single spectrum with high signal-to-noise ratio. Our finding that dE nuclei are younger and more metal rich than globular clusters establishes important benchmarks that future dE formation theories will consider. We also establish a means to identify GCs whose parent galaxies are uncertain, which allows us to make comparisons between this GC group and the satellite GCs.

Possibilidade de aplicação de misturas de herbicidas de ação total com Jato dirigido em mamoneira de porte anão Possibility of applaying total action herbicide tank mixture using direct sprayer on dwarf internode castor bean

Directory of Open Access Journals (Sweden)

C.D.G. Maciel

2008-06-01

Full Text Available Com o objetivo de avaliar os efeitos da aplicação em jato dirigido com e sem proteção do bico de pulverização através de chapéu-de-napoleão para misturas de herbicidas de ação total na cultura da mamoneira de porte anão, na safra 2004/2005, um experimento foi conduzido no município de Garça-SP, utilizando-se o híbrido Lyra e espaçamento de 1,0 x 0,5 m. O delineamento experimental utilizado foi o de blocos casualizados, com tratamentos em esquema fatorial 2 x 10, com quatro repetições, em que o primeiro fator representou a forma de aplicação de jato dirigido com e sem uso de chapéu-de-napoleão e o segundo os herbicidas: glyphosate (0,72 kg ha-1; glyphosate + 2,4-D (0,72 + 0,35 kg ha-1; glyphosate + flumioxazin (0,72 + 0,025 kg ha-1; glyphosate + carfentrazone-ethyl (0,72 + 0,016 kg ha-1; glyphosate + diuron (0,72 + 0,75 kg ha-1; MSMA + diuron (1,44+ 0,75 kg ha-1; paraquat + diuron (0,9 kg ha-1; paraquat + diquat (0,20 + 0,20 kg ha-1; paraquat + bentazon (0,40 + 0,48 kg ha-1; e testemunha capinada. A aplicação dos herbicidas foi feita em pós-emergência das plantas daninhas, nas entrelinhas da cultura, utilizando-se pulverizador costal pressurizado com CO2, com uma ponta XR 8002-VS para o uso de chapéu-de-napoleão e duas pontas XR 11002-VS, espaçadas de 50 cm, para condição sem proteção, ambas com consumo de calda equivalente a 200 L ha-1. O herbicida glyphosate e as misturas de paraquat + bentazon, glyphosate + 2,4-D e paraquat + diquat proporcionaram os maiores níveis de produtividade da mamoneira Lyra quando aplicados em jato dirigido e com auxílio de chapéu-de-napoleão. As misturas paraquat + bentazon (0,40 + 0,48 kg ha-1 e paraquat + diquat (0,20 + 0,20 kg ha-1 demonstraram ser as mais indicadas para aplicação em jato dirigido com proteção do bico de pulverização.An experiment was carried out in Garca-SP to evaluate the effects of application using a direct sprayer with and without "Napoleons's hat

Caracterização tecnológica de misturas solo-grits para pavimentos de estradas florestais: influência do tratamento térmico do grits na resistência mecânica das misturas Technological characterization of soil-grits mixtures for forest road pavements: influence of grits thermal treatment on the mechanical strength of mixtures

Directory of Open Access Journals (Sweden)

Carlos Cardoso Machado

2007-01-01

Full Text Available Analisou-se a influência do tratamento térmico do resíduo grits na resistência mecânica de misturas solo-grits para aplicações em pavimentos de estradas florestais. O programa de ensaios de laboratório englobou: (i dois solos residuais de gnaisse da Zona da Mata Norte de Minas Gerais; (ii um resíduo da indústria da celulose denominado grits, que é composto de cal não-hidratada e areia, entre outros produtos; (iii amostras de grits submetidas ao tratamento térmico em mufla sob temperaturas de 600, 700, 800 e 900 ºC antes da moldagem dos corpos-de-prova das misturas solo-grits; (iv corpos-de-prova das misturas preparadas com o grits tratado termicamente, com 24% de grits em relação ao peso seco dos solos, compactados nas energias dos ensaios Proctor intermediário e modificado e curados por 7 e 28 dias em câmara úmida, sob condições de aproximadamente 22 ºC de temperatura e 100% de umidade relativa do ar; e (v imersão completa dos corpos-de-prova das misturas solo-grits em água, pelo período de quatro horas, antes da determinação de suas resistências em ensaios de compressão não-confinada. Os resultados do programa de ensaios de laboratório indicaram que o tratamento térmico produziu amostras de grits mais reativas, podendo-se associar melhor desempenho mecânico às temperaturas de 800 e 900 ºC para o solo 1 e 800 ºC para o solo 2.The objective of this paper was to analyze the influence of grits thermal treatment on the mechanical strength of soil-grits mixtures. The laboratory testing program included: (i two residual gneiss soils from the Zona da Mata, Northern Minas Gerais; (ii waste from the cellulose industry, namely grits, composed by non-hydrated lime and sand, among others by-products; (iii grits samples submitted to thermal treatment in a muffle at the temperatures of 600, 700, 800 and 900 ºC before soils-grits specimens preparation; (iv soils-grits specimens containing 24% of treated grits in relation

Extragalactic globular clusters. I. The metallicity calibration

International Nuclear Information System (INIS)

Brodie, J.P.; Huchra, J.P.

1990-01-01

The ability of absorption-line strength indices, measured from integrated globular cluster spectra, to predict mean cluster metallicity is explored. Statistical criteria, are used to identify the six best indices out of about 20 measured in a large sample of Galactic and M31 cluster spectra. Linear relations between index and metallicity have been derived along with new calibrations of infrared colors (V - K, J - K, and CO) versus Fe/H. Estimates of metallicity from the six spectroscopic index-metallicity relations have been combined in three different ways to identify the most efficient estimator and the minimum bias estimator of Fe/H - the weighted mean. This provides an estimate of Fe/H accurate to about 15 percent. 37 refs

Multiple populations along the asymptotic giant branch of the globular cluster M 4

NARCIS (Netherlands)

Lardo, C.; Salaris, M.; Savino, A.; Donati, P.; Stetson, P. B.; Cassisi, S.

2016-01-01

Nearly all Galactic globular clusters host stars that display characteristic abundance anti-correlations, like the O-rich/Na-poor pattern typical of field halo stars, together with O-poor/Na-rich additional components. A recent spectroscopic investigation questioned the presence of O-poor/Na-rich

A Wide-Field Photometric Survey for Extratidal Tails Around Five Metal-Poor Globular Clusters in the Galactic Halo

Science.gov (United States)

Chun, Sang-Hyun; Kim, Jae-Woo; Sohn, Sangmo T.; Park, Jang-Hyun; Han, Wonyong; Kim, Ho-Il; Lee, Young-Wook; Lee, Myung Gyoon; Lee, Sang-Gak; Sohn, Young-Jong

2010-02-01

Wide-field deep g'r'i' images obtained with the Megacam of the Canada-France-Hawaii Telescope are used to investigate the spatial configuration of stars around five metal-poor globular clusters M15, M30, M53, NGC 5053, and NGC 5466, in a field-of-view ~3°. Applying a mask filtering algorithm to the color-magnitude diagrams of the observed stars, we sorted cluster's member star candidates that are used to examine the characteristics of the spatial stellar distribution surrounding the target clusters. The smoothed surface density maps and the overlaid isodensity contours indicate that all of the five metal-poor globular clusters exhibit strong evidence of extratidal overdensity features over their tidal radii, in the form of extended tidal tails around the clusters. The orientations of the observed extratidal features show signatures of tidal tails tracing the clusters' orbits, inferred from their proper motions, and effects of dynamical interactions with the Galaxy. Our findings include detections of a tidal bridge-like feature and an envelope structure around the pair of globular clusters M53 and NGC 5053. The observed radial surface density profiles of target clusters have a deviation from theoretical King models, for which the profiles show a break at 0.5-0.7rt , extending the overdensity features out to 1.5-2rt . Both radial surface density profiles for different angular sections and azimuthal number density profiles confirm the overdensity features of tidal tails around the five metal-poor globular clusters. Our results add further observational evidence that the observed metal-poor halo globular clusters originate from an accreted satellite system, indicative of the merging scenario of the formation of the Galactic halo. Based on observations carried out at the Canada-France-Hawaii Telescope, operated by the National Research Council of Canada, the Centre National de la Recherche Scientifique de France, and the University of Hawaii. This is part of the

Ages of Globular Clusters from HIPPARCOS Parallaxes of Local Subdwarfs

Science.gov (United States)

Gratton, Raffaele G.; Fusi Pecci, Flavio; Carretta, Eugenio; Clementini, Gisella; Corsi, Carlo E.; Lattanzi, Mario

1997-12-01

We report here initial but strongly conclusive results for absolute ages of Galactic globular clusters (GGCs). This study is based on high-precision trigonometric parallaxes from the HIPPARCOS satellite coupled with accurate metal abundances ([Fe/H], [O/Fe], and [α/Fe]) from high-resolution spectroscopy for a sample of about thirty subdwarfs. Systematic effects due to star selection (Lutz-Kelker corrections to parallaxes) and the possible presence of undetected binaries in the sample of bona fide single stars are examined, and appropriate corrections are estimated. They are found to be small for our sample. The new data allow us to reliably define the absolute location of the main sequence (MS) as a function of metallicity. These results are then used to derive distances and ages for a carefully selected sample of nine globular clusters having metallicities determined from high-dispersion spectra of individual giants according to a procedure totally consistent with that used for the field subdwarfs. Very precise and homogeneous reddening values have also been independently determined for these clusters. Random errors for our distance moduli are +/-0.08 mag, and systematic errors are likely of the same order of magnitude. These very accurate distances allow us to derive ages with internal errors of ~12% (+/-1.5 Gyr). The main results are: 1. HIPPARCOS parallaxes are smaller than corresponding ground-based measurements, leading, in turn, to longer distance moduli (~0.2 mag) and younger ages (~2.8 Gyr). 2. The distance to NGC 6752 derived from our MS fitting is consistent with that determined using the white dwarf cooling sequence. 3. The relation between the zero-age HB (ZAHB) absolute magnitude and metallicity for the nine program clusters is MV(ZAHB)=(0.22+/-0.09)([Fe/H]+1.5)+(0.49+/-0.04) . This relation is fairly consistent with some of the most recent theoretical models. Within quoted errors, the slope is in agreement with that given by the Baade-Wesselink (BW

EFEITO DOS PARÂMETROS DE EXTRUSÃO NAS PROPRIEDADES FÍSICAS DE EXTRUSADOS DE MISTURAS DE FÉCULA DE MANDIOCA E POLPA CÍTRICA

Directory of Open Access Journals (Sweden)

L. B. SOUZA

2008-11-01

Full Text Available

Neste trabalho buscou-se avaliar os efeitos das condições operacionais de extrusão na produção de snacks ricos em fibras a partir de fécula de mandioca e polpa cítrica. Foi avaliado o efeito da umidade, porcentagem de fibras e temperatura de extrusão sobre as propriedades físicas dos extrusados. Os resultados mostraram que a temperatura de extrusão influenciou de forma significativa o volume específico, o qual variou de 1,71 mL/g a 8,54mL/g, e o índice de solubilidade em água, o qual variou de 44,03% a 68,45%. O índice de expansão dos extrusados foi afetado pela porcentagem de fibras e variou de 2.21 a 3.49. O teor de umidade das misturas e a porcentagem de fibras tiveram efeito sobre a cor dos produtos. Para a produção de produtos expandidos, a base de fécula de mandioca e polpa de laranja tiveram as melhores condições operacionais: 10% de fibras e 14% de umidade na mistura com temperatura de extrusão de 95ºC.

THE CENTRAL BLUE STRAGGLER POPULATION IN FOUR OUTER-HALO GLOBULAR CLUSTERS

Energy Technology Data Exchange (ETDEWEB)

Beccari, Giacomo; Luetzgendorf, Nora [European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching bei Muenchen (Germany); Olczak, Christoph [Astronomisches Rechen-Institut (ARI), Zentrum fuer Astronomie Universitaet Heidelberg, Moenchhofstrasse 1214, 69120 Heidelberg (Germany); Ferraro, Francesco R.; Lanzoni, Barbara [Dipartimento di Astronomia, Universita degli Studi di Bologna, via Ranzani 1, I-40127 Bologna (Italy); Carraro, Giovanni; Boffin, Henri M. J. [European Southern Observatory, Alonso de Cordova 3107, Santiago de Chile (Chile); Stetson, Peter B. [National Research Council of Canada, Herzberg Institute of Astrophysics, 5071 West Saanich Road, Victoria, BC V9E 2E7 (Canada); Sollima, Antonio [INAF-Osservatorio Astronomico di Padova, Vicolo dell' Osservatorio 5, 35122 Padova (Italy)

2012-08-01

Using Hubble Space Telescope/Wide Field Planetary Camera 2 data, we have performed a comparative study of the Blue Straggler Star (BSS) populations in the central regions of the globular clusters (GCs) AM 1, Eridanus, Palomar 3, and Palomar 4. Located at distances R{sub GC} > 50 kpc from the Galactic center, these are (together with Palomar 14 and NGC 2419) the most distant clusters in the halo. We determine their color-magnitude diagrams and centers of gravity. The four clusters turn out to have similar ages (10.5-11 Gyr), significantly smaller than those of the inner-halo globulars, and similar metallicities. By exploiting wide-field ground-based data, we build the most extended radial density profiles from resolved star counts ever published for these systems. These are well reproduced by isotropic King models of relatively low concentration. BSSs appear to be significantly more centrally segregated than red giants in all GCs, in agreement with the estimated core and half-mass relaxation times which are smaller than the cluster ages. Assuming that this is a signature of mass segregation, we conclude that AM 1 and Eridanus are slightly dynamically more evolved than Pal 3 and Pal 4.

THE METALLICITY BIMODALITY OF GLOBULAR CLUSTER SYSTEMS: A TEST OF GALAXY ASSEMBLY AND OF THE EVOLUTION OF THE GALAXY MASS-METALLICITY RELATION

International Nuclear Information System (INIS)

Tonini, Chiara

2013-01-01

We build a theoretical model to study the origin of the globular cluster metallicity bimodality in the hierarchical galaxy assembly scenario. The model is based on empirical relations such as the galaxy mass-metallicity relation [O/H]-M star as a function of redshift, and on the observed galaxy stellar mass function up to redshift z ∼ 4. We make use of the theoretical merger rates as a function of mass and redshift from the Millennium simulation to build galaxy merger trees. We derive a new galaxy [Fe/H]-M star relation as a function of redshift, and by assuming that globular clusters share the metallicity of their original parent galaxy at the time of their formation, we populate the merger tree with globular clusters. We perform a series of Monte Carlo simulations of the galaxy hierarchical assembly, and study the properties of the final globular cluster population as a function of galaxy mass, assembly and star formation history, and under different assumptions for the evolution of the galaxy mass-metallicity relation. The main results and predictions of the model are the following. (1) The hierarchical clustering scenario naturally predicts a metallicity bimodality in the galaxy globular cluster population, where the metal-rich subpopulation is composed of globular clusters formed in the galaxy main progenitor around redshift z ∼ 2, and the metal-poor subpopulation is composed of clusters accreted from satellites, and formed at redshifts z ∼ 3-4. (2) The model reproduces the observed relations by Peng et al. for the metallicities of the metal-rich and metal-poor globular cluster subpopulations as a function of galaxy mass; the positions of the metal-poor and metal-rich peaks depend exclusively on the evolution of the galaxy mass-metallicity relation and the [O/Fe], both of which can be constrained by this method. In particular, we find that the galaxy [O/Fe] evolves linearly with redshift from a value of ∼0.5 at redshift z ∼ 4 to a value of ∼0.1 at

The Case of the Missing Cyanogen-rich AGB Stars in Galactic Globular Clusters

DEFF Research Database (Denmark)

Campbell, S. W.; Yong, D.; Wylie-de Boer, E. C.

2012-01-01

The handful of available observations of AGB stars in Galactic Globular Clusters suggest that the GC AGB populations are dominated by cyanogen-weak stars (eg. Norris et al. 1981; Sneden et al. 2000). This contrasts strongly with the distributions on the RGB (and other) populations, which generall...

Infrared and laser-Raman spectroscopic studies of thermally-induced globular protein gels.

Science.gov (United States)

Clark, A H; Saunderson, D H; Suggett, A

1981-03-01

Infrared and laser-Raman spectroscopy have been used to follow secondary structure changes during the heat-set gelation of a number of aqueous (D2O) globular protein solutions. Measurements of the infrared Amide I' absorption band around 1650 cm-1, for BSA gels of varying clarity and texture, have shown that the very considerable variations in network structure underlying these materials are not reflected in obvious differences in secondary structure. In all cases aggregation is accompanied by development of beta-sheet of a kind common in fibrous protein systems, but for BSA at least this does not appear to vary significantly in amount from one gel type to another. Infrared studies of gels formed from other protein systems have confirmed this tendency for beta-sheet to develop during aggregation, and the tendency is further substantiated by laser-Raman evidence which provides the extra information that in most of the examples studied alpha-helix content simultaneously falls. From these, and other observations, some generalisations are made about the thermally-induced sol-to-gel transformations of globular proteins.

THE DYNAMICAL EFFECTS OF WHITE DWARF BIRTH KICKS IN GLOBULAR STAR CLUSTERS

International Nuclear Information System (INIS)

Fregeau, John M.; Richer, Harvey B.; Rasio, Frederic A.; Hurley, Jarrod R.

2009-01-01

Recent observations of the white dwarf (WD) populations in the Galactic globular cluster NGC 6397 suggest that WDs receive a kick of a few km s -1 shortly before they are born. Using our Monte Carlo cluster evolution code, which includes accurate treatments of all relevant physical processes operating in globular clusters, we study the effects of the kicks on their host cluster and on the WD population itself. We find that in clusters whose velocity dispersion is comparable to the kick speed, WD kicks are a significant energy source for the cluster, prolonging the initial cluster core contraction phase significantly so that at late times the cluster core-to-half-mass radius ratio is a factor of up to ∼10 larger than in the no-kick case. WD kicks thus represent a possible resolution of the large discrepancy between observed and theoretically predicted values of this key structural parameter. Our modeling also reproduces the observed trend for younger WDs to be more extended in their radial distribution in the cluster than older WDs.

A Fossil Bulge Globular Cluster Revealed by very Large Telescope Multi-conjugate Adaptive Optics

Czech Academy of Sciences Publication Activity Database

Ortolani, S.; Barbuy, B.; Momany, Y.; Saviane, I.; Bica, E.; Jílková, L.; Salerno, G.M.; Jungwiert, Bruno

2011-01-01

Roč. 737, č. 1 (2011), 31/1-31/9 ISSN 0004-637X Institutional research plan: CEZ:AV0Z10030501 Keywords : galaxy * globular clusters Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 6.024, year: 2011

No Evidence for Multiple Stellar Populations in the Low-mass Galactic Globular Cluster E 3

Science.gov (United States)

Salinas, Ricardo; Strader, Jay

2015-08-01

Multiple stellar populations are a widespread phenomenon among Galactic globular clusters. Even though the origin of the enriched material from which new generations of stars are produced remains unclear, it is likely that self-enrichment will be feasible only in clusters massive enough to retain this enriched material. We searched for multiple populations in the low mass (M˜ 1.4× {10}4 {M}⊙ ) globular cluster E3, analyzing SOAR/Goodman multi-object spectroscopy centered on the blue cyanogen (CN) absorption features of 23 red giant branch stars. We find that the CN abundance does not present the typical bimodal behavior seen in clusters hosting multistellar populations, but rather a unimodal distribution that indicates the presence of a genuine single stellar population, or a level of enrichment much lower than in clusters that show evidence for two populations from high-resolution spectroscopy. E3 would be the first bona fide Galactic old globular cluster where no sign of self-enrichment is found. Based on observations obtained at the Southern Astrophysical Research (SOAR) Telescope, which is a joint project of the Ministério da Ciência, Tecnologia, e Inovação (MCTI) da República Federativa do Brasil, the US National Optical Astronomy Observatory (NOAO), the University of North Carolina at Chapel Hill (UNC), and Michigan State University (MSU).

Sensibilidade de cultivares de cana-de-açúcar à mistura trifloxysulfuron-sodium + ametryn Sensitivity of sugarcane cultivars to trifloxysulfuron sodium + ametryn mixture

Directory of Open Access Journals (Sweden)

E.A. Ferreira

2005-03-01

Full Text Available O trabalho constou de dois ensaios e teve como objetivo avaliar a sensibilidade de 11 cultivares (SP80-1842, SP79-1011, SP81-3250, SP80-1816, RB855113, RB835486, RB845210, RB867515, RB928064, RB72454 e RB855536 e quatro clones (RB947643, RB855002, RB957712 e RB957689 de cana-de-açúcar à mistura pré-formulada dos herbicidas trifloxysulfuron-sodium (18,5 g kg-1 + ametryn (731,5 g kg-1, denominada Krismat®. Os cultivares e os clones foram cultivados em vasos em ambiente não-protegido. Em ambos os ensaios a mistura herbicida foi aplicada aos 60 dias após a brotação (DAB. No ensaio 1, a mistura herbicida foi aplicada em dose única de 2,00 kg ha-1 sobre todos os cultivares e clones, enquanto no ensaio 2 a mistura foi aplicada nas doses de 1,00, 2,00 e 6,00 kg ha¹ sobre os cultivares RB855113 e RB867515. Após a aplicação do herbicida e aos 45 dias após a aplicação dos tratamentos (DAT, por ocasião da colheita, foram feitas avaliações semanais de fitotoxicidade, avaliando-se também a biomassa seca da parte aérea dos 11 cultivares e dos quatro clones. As variáveis altura da planta, número de folhas, área foliar e biomassa seca da parte aérea e do caule foram avaliadas no segundo ensaio. O cultivar RB855113 apresentou alta sensibilidade à mistura herbicida; os genótipos SP80-1842, SP801816, SP79-1011 e RB957689 apresentaram sensibilidade média; e os demais mostraram boa tolerância a esse produto. Para o cultivar RB855113, o maior índice de toxidez foi observado no período de 20 a 27 DAT. Nesse período observou-se redução da altura da planta, do número de folhas, da área foliar e da biomassa seca da parte aérea e do caule com o aumento das doses do produto. O cultivar RB867515 apresentou-se tolerante às menores doses do herbicida, porém, na maior dose testada, ele se mostrou sensível, observando-se redução nas características avaliadas.The objective of this study was to evaluate the sensitivity of 11 cultivars

Características físicas e mecânicas de misturas de solo, cimento e cinzas de bagaço de cana-de-açúcar Physical and mechanical characteristics of soil-cement-bagasse ash mixtures

Directory of Open Access Journals (Sweden)

Martha Del C. Mesa Valenciano

2004-12-01

Full Text Available Este trabalho teve por finalidade analisar algumas características de misturas de solo, cimento e cinzas de bagaço de cana-de-açúcar para sua possível utilização na fabricação de materiais alternativos de construção. Para tal, amostras de cinzas de bagaço de cana-de-açúcar foram submetidas a um tratamento prévio que consistia de peneiramento e moagem, antes de serem incorporadas às misturas de solo e cimento. Diferentes combinações de cimento-cinzas foram estudadas, determinando-se, para cada uma delas, a consistência normal e a resistência à compressão simples, aos 7 e 28 dias. Posteriormente, corpos-de-prova moldados com tais misturas de solo-cimento-cinzas foram submetidos a ensaios de compactação, compressão simples e absorção de água. Os resultados indicaram a possibilidade de substituir até 20% do cimento Portland, na mistura, por cinzas de bagaço de cana-de-açúcar, sem prejuízo da resistência à compressão simples.This work was done with the objective of studying some physical and mechanical characteristics of the sugarcane bagasse ash added to a soil-cement mixture, in order to obtain an alternative construction material. The sugarcane bagasse ash pre-treatment included both sieving and grinding, before mixing with soil and cement. Different proportions of cement-ash were tested by determining its standard consistence and its compressive resistance at 7 and 28 days age. The various treatments were subsequently applied to the specimens molded with different soil-cement-ash mixtures which in turns were submitted to compaction, unconfined compression and water absorption laboratory tests. The results showed that it is possible to replace up to 20% of Portland cement by sugarcane bagasse ash without any damage to the mixture's compressive strength.

Dynamics of proteins at low temperatures: fibrous vs. globular

Science.gov (United States)

Foucat, L.; Renou, J.-P.; Tengroth, C.; Janssen, S.; Middendorf, H. D.

We have measured quasielastic neutron scattering from H2O-hydrated collagen and haemoglobin at Tτ>10 ps. Relative to haemoglobin, the 200-K dynamic transition is shifted upward by 20-25 K in collagen, and the T-dependence of m.-sq. displacements derived from Sqe(Q;T) suggests that in triple-helical systems there are three rather than two regimes: one up to around 120K (probably purely harmonic), an intermediate quasiharmonic region with a linear dependence up to 240K, followed by a steeper nonlinear rise similar to that in globular proteins.

Imprint of galaxy formation and evolution on globular cluster properties

OpenAIRE

Bekki, Kenji

2006-01-01

We discuss the origin of physical properties of globular cluster systems (GCSs) in galaxies in terms of galaxy formation and evolution processes. Based on numerical simulations of dynamical evolution of GCSs in galaxies, we particularly discuss (1) the origin of radial density profiles of GCSs, (2) kinematics of GCSs in elliptical galaxies, (3) transformation from nucleated dwarf galaxies into GCs (e.g., omega Centauri), and (4) the origin of GCSs in the Large Magellanic Cloud (LMC).

Understanding the central kinematics of globular clusters with simulated integrated-light IFU observations

Science.gov (United States)

Bianchini, Paolo; Norris, Mark A.; van de Ven, Glenn; Schinnerer, Eva

2015-10-01

The detection of intermediate-mass black holes in the centres of globular clusters is highly controversial, as complementary observational methods often deliver significantly different results. In order to understand these discrepancies, we develop a procedure to simulate integral field unit (IFU) observations of globular clusters: Simulating IFU Star Cluster Observations (SISCO). The inputs of our software are realistic dynamical models of globular clusters that are then converted in a spectral data cube. We apply SISCO to Monte Carlo cluster simulations with a realistic number of stars and concentrations. Using independent realizations of a given simulation we are able to quantify the stochasticity intrinsic to the problem of observing a partially resolved stellar population with integrated-light spectroscopy. We show that the luminosity-weighted IFU observations can be strongly biased by the presence of a few bright stars that introduce a scatter in the velocity dispersion measurements up to ≃40 per cent around the expected value, preventing any sound assessment of the central kinematic and a sensible interpretation of the presence/absence of an intermediate-mass black hole. Moreover, we illustrate that, in our mock IFU observations, the average kinematic tracer has a mass of ≃0.75 M⊙, only slightly lower than the mass of the typical stars examined in studies of resolved line-of-sight velocities of giant stars. Finally, in order to recover unbiased kinematic measurements we test different masking techniques that allow us to remove the spaxels dominated by bright stars, bringing the scatter down to a level of only a few per cent. The application of SISCO will allow us to investigate state-of-the-art simulations as realistic observations.

Hubble Space Telescope Observations of cD Galaxies and Their Globular Cluster Systems

Science.gov (United States)

Jordán, Andrés; Côté, Patrick; West, Michael J.; Marzke, Ronald O.; Minniti, Dante; Rejkuba, Marina

2004-01-01

We have used WFPC2 on the Hubble Space Telescope (HST) to obtain F450W and F814W images of four cD galaxies (NGC 541 in Abell 194, NGC 2832 in Abell 779, NGC 4839 in Abell 1656, and NGC 7768 in Abell 2666) in the range 5400 km s-1cluster (GC) systems reveals no anomalies in terms of specific frequencies, metallicity gradients, average metallicities, or the metallicity offset between the globular clusters and the host galaxy. We show that the latter offset appears roughly constant at Δ[Fe/H]~0.8 dex for early-type galaxies spanning a luminosity range of roughly 4 orders of magnitude. We combine the globular cluster metallicity distributions with an empirical technique described in a series of earlier papers to investigate the form of the protogalactic mass spectrum in these cD galaxies. We find that the observed GC metallicity distributions are consistent with those expected if cD galaxies form through the cannibalism of numerous galaxies and protogalactic fragments that formed their stars and globular clusters before capture and disruption. However, the properties of their GC systems suggest that dynamical friction is not the primary mechanism by which these galaxies are assembled. We argue that cD's instead form rapidly, via hierarchical merging, prior to cluster virialization. Based on observations with the NASA/ESA Hubble Space Telescope obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555 Based in part on observations obtained at the European Southern Observatory, for VLT program 68.D-0130(A).

New cataclysmic variables and other exotic binaries in the globular cluster 47 Tucanae*

Science.gov (United States)

Rivera Sandoval, L. E.; van den Berg, M.; Heinke, C. O.; Cohn, H. N.; Lugger, P. M.; Anderson, J.; Cool, A. M.; Edmonds, P. D.; Wijnands, R.; Ivanova, N.; Grindlay, J. E.

2018-04-01

We present 22 new (+3 confirmed) cataclysmic variables (CVs) in the non-core-collapsed globular cluster 47 Tucanae (47 Tuc). The total number of CVs in the cluster is now 43, the largest sample in any globular cluster so far. For the identifications we used near-ultraviolet (NUV) and optical images from the Hubble Space Telescope, in combination with X-ray results from the Chandra X-ray Observatory. This allowed us to build the deepest NUV CV luminosity function of the cluster to date. We found that the CVs in 47 Tuc are more concentrated towards the cluster centre than the main-sequence turn-off stars. We compared our results to the CV populations of the core-collapsed globular clusters NGC 6397 and NGC 6752. We found that 47 Tuc has fewer bright CVs per unit mass than those two other clusters. That suggests that dynamical interactions in core-collapsed clusters play a major role creating new CVs. In 47 Tuc, the CV population is probably dominated by primordial and old dynamically formed systems. We estimated that the CVs in 47 Tuc have total masses of ˜1.4 M⊙. We also found that the X-ray luminosity function of the CVs in the three clusters is bimodal. Additionally, we discuss a possible double degenerate system and an intriguing/unclassified object. Finally, we present four systems that could be millisecond pulsar companions given their X-ray and NUV/optical colours. For one of them we present very strong evidence for being an ablated companion. The other three could be CO or He white dwarfs.

Elaboração de bebida composta por mistura de garapa parcialmente clarificada-estabilizada e sucos de frutas ácidas Elaboration of beverage composed by blends of clarified-stabilized sugar cane and juice's acid fruits

Directory of Open Access Journals (Sweden)

Patricia Prati

2005-03-01

Full Text Available O Brasil é grande produtor e consumidor de sucos de frutas, além de ser o maior produtor mundial de cana-de-açúcar. O caldo de cana, também conhecido popularmente como garapa, é uma bebida de grande aceitação pelo consumidor brasileiro, e nos vendedores ambulantes, normalmente é comercializada em misturas com sucos de frutas ácidas. O trabalho teve como objetivo avaliar físico-química e sensorialmente as misturas de garapa parcialmente clarificada-estabilizada com sucos de limão, abacaxi e maracujá, e posteriormente eleger a bebida preferida do ponto de vista sensorial. Foram realizados Testes Sensoriais de Aceitação e de Intenção de Compra. As outras determinações foram pH, ºBrix, acidez, relação ºBrix/Acidez, teor de ácido ascórbico, cor e turbidez. Os resultados das análises sensoriais indicaram que a mistura preferida foi aquela elaborada com garapa clarificada e 5% de suco de maracujá, seguida da mistura que continha 10% de suco de abacaxi. No entanto, pelo Teste de Intenção de Compra a maioria dos consumidores afirmaram que "possivelmente compraria" todas as misturas avaliadas. Todos os produtos apresentaram boa retenção nos níveis de vitamina C após o tratamento térmico. Microbiologicamente todas as bebidas apresentaram-se adequadas para consumo.Brazil is a great producer and consumer of fruit juices, in addition to being the World's largest producer of sugar cane. Sugar cane juice, popularly known as garapa, is a beverage highly appreciated by the Brazilian population and the street vendors usually sell it in mixtures with acid fruit juices. The objective of this study was the sensory and physical-chemical evaluation of partially clarified-stabilized sugar cane juice in mixtures with lemon, pineapple and passion fruit juices, aimed at choosing the most appreciated beverage from the sensory point of view. The sensory analyses were those of acceptance and intention to buy and the remaining determinations

Production of surfactants from bio-materials

OpenAIRE

Fonseca, Tiago Gonçalves da

2009-01-01

Este trabalho foi desenvolvido no âmbito de um projecto europeu, BIOPRODUCTION, tendo em vista o desenvolvimento de dois tipos de biomaterias funcionais: ésteres de açúcares com ácidos gordos (SFAE) e metacrilatos funcionais. A síntese laboratorial do biosurfactante SFAE foi efectuada utilizando como matérias-primas diferentes sacáridos, nomeadamente sacarose, glucose e melaço de cana-de-açúcar (mistura de polissacáridos), e ésteres metílicos de ácidos gordos (FAME) de óleos vegetais, tai...

Produção de biscoitos extrusados de polvilho azedo com fibras: efeito de parâmetros operacionais sobre as propriedades físicas

OpenAIRE

Camargo,Karina Fernandes de; Leonel,Magali; Mischan,Martha Maria

2008-01-01

Neste trabalho buscou-se avaliar o efeito de parâmetros operacionais do processo de extrusão no desenvolvimento de biscoitos de polvilho com fibras, utilizando como matérias-primas o polvilho azedo e o farelo de mandioca. O processamento foi realizado em um extrusor mono-rosca, sendo considerados parâmetros variáveis: temperatura na 3ª zona de extrusão, umidade e porcentagem de fibras na mistura. Para analisar o efeito combinado das variáveis independentes nas características tecnológicas dos...

Influência da temperatura na solubilidade de beta-caroteno em solventes orgânicos à pressão ambiente

OpenAIRE

Três,Marcus Vinícius; Francheschi,Elton; Borges,Gustavo Rodrigues; Dariva,Cláudio; Corazza,Fernanda de Castilhos; Oliveira,José Vladimir; Corazza,Marcos Lúcio

2007-01-01

O presente trabalho reporta dados experimentais de solubilidade em pressão ambiente de beta-caroteno em solventes orgânicos puros (etanol, acetona, acetato de etila e diclorometano) e em misturas de tais solventes no intervalo de temperatura de 10 a 60 °C. Para este fim, adotou-se o método gravimétrico para a determinação da solubilidade, utilizando células encamisadas de equilíbrio. Os resultados mostraram que valores mais elevados de solubilidade são obtidos quando foram empregados solvente...

SEARCH FOR RED DWARF STARS IN GLOBULAR CLUSTER NGC 6397

Science.gov (United States)

2002-01-01

Left A NASA Hubble Space Telescope image of a small region (1.4 light-years across) in the globular star cluster NGC 6397. Simulated stars (diamonds) have been added to this view of the same region of the cluster to illustrate what astronomers would have expected to see if faint red dwarf stars were abundant in the Milky Way Galaxy. The field would then contain 500 stars, according to theoretical calculations. Right The unmodified HST image shows far fewer stars than would be expected, according to popular theories of star formation. HST resolves about 200 stars. The stellar density is so low that HST can literally see right through the cluster and resolve far more distant background galaxies. From this observation, scientists have identified the surprising cutoff point below which nature apparently doesn't make many stars smaller that 1/5 the mass of our Sun. These HST findings provide new insights into star formation in our Galaxy. Technical detail:The globular cluster NGC 6397, one of the nearest and densest agglomerations of stars, is located 7,200 light-years away in the southern constellation Ara. This visible-light picture was taken on March 3, 1994 with the Wide Field Planetary Camera 2, as part the HST parallel observing program. Credit: F. Paresce, ST ScI and ESA and NASA

Variable Stars in Large Magellanic Cloud Globular Clusters. III. Reticulum

Science.gov (United States)

Kuehn, Charles A.; Dame, Kyra; Smith, Horace A.; Catelan, Márcio; Jeon, Young-Beom; Nemec, James M.; Walker, Alistair R.; Kunder, Andrea; Pritzl, Barton J.; De Lee, Nathan; Borissova, Jura

2013-06-01

This is the third in a series of papers studying the variable stars in old globular clusters in the Large Magellanic Cloud. The primary goal of this series is to look at how the characteristics and behavior of RR Lyrae stars in Oosterhoff-intermediate systems compare to those of their counterparts in Oosterhoff-I/II systems. In this paper we present the results of our new time-series BVI photometric study of the globular cluster Reticulum. We found a total of 32 variables stars (22 RRab, 4 RRc, and 6 RRd stars) in our field of view. We present photometric parameters and light curves for these stars. We also present physical properties, derived from Fourier analysis of light curves, for some of the RR Lyrae stars. We discuss the Oosterhoff classification of Reticulum and use our results to re-derive the distance modulus and age of the cluster. Based on observations taken with the SMARTS 1.3 m telescope operated by the SMARTS Consortium and observations taken at the Southern Astrophysical Research (SOAR) telescope, which is a joint project of the Ministério da Ciência, Tecnologia, e Inovação (MCTI) da República Federativa do Brasil, the U.S. National Optical Astronomy Observatory (NOAO), the University of North Carolina at Chapel Hill (UNC), and Michigan State University (MSU).

VLT/UVES abundances of individual stars in the Fornax dwarf spheroidal globular clusters

NARCIS (Netherlands)

Letarte, B.; Hill, V.; Jablonka, P.; Tolstoy, E.; Randich, S; Pasquini, L

2006-01-01

We present high resolution abundance analysis of nine stars belonging to three of the five globular clusters (GCs) of the Fornax dwarf galaxy. The spectra were taken with UVES at a resolution of 43 000. We find them to be slightly more metal-poor than what was previously calculated with other

Search for continuous gravitational waves from neutron stars in globular cluster NGC 6544

NARCIS (Netherlands)

Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M. R.; Acernese, F.; Ackley, K.; Adams, C.; Phythian-Adams, A.T.; Addesso, P.; Adhikari, R. X.; Adya, V. B.; Affeldt, C.; Agathos, M.; Agatsuma, K.; Aggarwal, N.T.; Aguiar, O. D.; Aiello, L.; Ain, A.; Allen, B.; Allocca, A.; Altin, P. A.; Anderson, S. B.; Anderson, W. G.; Arai, K.; Araya, M. C.; Arceneaux, C. C.; Areeda, J. S.; Arnaud, N.; Arun, K. G.; Ascenzi, S.; Ashton, G.; Ast, M.; Aston, S. M.; Astone, P.; Aufmuth, P.; Aulbert, C.; Babak, S.; Bacon, P.; Bader, M. K. M.; Baker, P. T.; Baldaccini, F.; Ballardin, G.; Ballmer, S. W.; Barayoga, J. C.; Barclay, S. E.; Barish, B. C.; Barker, R.D.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Barta, D.; Bartlett, J.; Bartos, I.; Bassiri, R.; Basti, A.; Batch, J. C.; Baune, C.; Bavigadda, V.; Bazzan, M.; Bejger, M.; Bell, A. S.; Berger, B. K.; Bergmann, G.; Berry, C. P. L.; Bersanetti, D.; Bertolini, A.; Betzwieser, J.; Bhagwat, S.; Bhandare, R.; Bilenko, I. A.; Billingsley, G.; Birch, M.J.; Birney, R.; Biscans, S.; Bisht, A.; Bitossi, M.; Biwer, C.; Bizouard, M. A.; Blackburn, J. K.; Blair, C. D.; Blair, D. G.; Blair, R. M.; Bloemen, A.L.S.; Bock, O.; Boer, M.; Bogaert, J.G.; Bogan, C.; Bohe, A.; Bond, T.C; Bondu, F.; Bonnand, R.; Boom, B. A.; Bork, R.; Boschi, V.; Bose, S.; Bouffanais, Y.; Bozzi, A.; Bradaschia, C.; Brady, P. R.; Braginsky, V. B.; Branchesi, M.; Brau, J. E.; Briant, T.; Brillet, A.; Brinkmann, M.; Brisson, V.; Brockill, P.; Broida, J. E.; Brooks, A. F.; Brown, A.D.; Brown, D.; Brown, N. M.; Brunett, S.; Buchanan, C. C.; Buikema, A.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Buskulic, D.; Buy, C.; Byer, R. L.; Cabero, M.; Cadonati, L.; Cagnoli, G.; Cahillane, C.; Bustillo, J. Calderon; Callister, T. A.; Calloni, E.; Camp, J. B.; Cannon, K. C.; Cao, J.; Capano, C. D.; Capocasa, E.; Carbognani, F.; Caride, S.; Diaz, J. Casanueva; Casentini, C.; Caudill, S.; Cavaglia, M.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cepeda, C. B.; Baiardi, L. Cerboni; Cerretani, G.; Cesarini, E.; Chamberlin, S. J.; Chan, M.; Chao, D. S.; Charlton, P.; Chassande-Mottin, E.; Cheeseboro, B. D.; Chen, H. Y.; Chen, Y; Cheng, C.; Chincarini, A.; Chiummo, A.; Cho, H. S.; Cho, M.; Chow, J. H.; Christensen, N.; Chu, Qian; Chua, S. S. Y.; Chung, E.S.; Ciani, G.; Clara, F.; Clark, J. A.; Cleva, F.; Coccia, E.; Cohadon, P. -F.; Colla, A.; Collette, C. G.; Cominsky, L.; Constancio, M., Jr.; Conte, A.; Conti, L.; Cook, D.; Corbitt, T. R.; Cornish, N.; Corsi, A.; Cortese, S.; Costa, A.C.; Coughlin, M. W.; Coughlin, S. B.; Coulon, J. -P.; Countryman, S. T.; Couvares, P.; Cowan, E. E.; Coward, D. M.; Cowart, M. J.; Coyne, D. C.; Coyne, R.; Craig, K.; Creighton, J. D. E.; Creighton, T. D.; Cripe, J.; Crowder, S. G.; Cumming, A.; Cunningham, Laura; Cuoco, E.; Dal Canton, T.; Danilishin, S. L.; D'Antonio, S.; Danzmann, K.; Darman, N. S.; Dasgupta, A.; Costa, C. F. Da Silva; Dattilo, V.; Dave, I.; Davier, M.; Davies, G. S.; Daw, E. J.; Day, R.; De, S.; Debra, D.; Debreczeni, G.; Degallaix, J.; De laurentis, M.; Deleglise, S.; Del Pozzo, W.; Denker, T.; Dent, T.; Dergachev, V.A.; Rosa, R.; DeRosa, R. T.; DeSalvo, R.; Devine, R. C.; Dhurandhar, S.; Diaz, M. C.; Di Fiore, L.; Giovanni, M. Di; Di Girolamo, T.; Di Lieto, A.; Di Pace, S.; Di Palma, I.; Di Virgilio, A.; Dolique, V.; Donovan, F.; Dooley, K. L.; Doravari, S.; Douglas, R.; Downes, T. P.; Drago, M.; Drever, R. W. P.; Driggers, J. C.; Ducrot, M.; Dwyer, S. E.; Edo, T. B.; Edwards, M. C.; Effler, A.; Eggenstein, H. -B.; Ehrens, P.; Eichholz, J.; Eikenberry, S. S.; Engels, W.; Essick, R. C.; Etzel, T.; Evans, T. M.; Evans, T. M.; Everett, R.; Factourovich, M.; Fafone, V.; Fair, H.; Fan, X.M.; Fang, Q.; Farinon, S.; Farr, B.; Farr, W. M.; Favata, M.; Fays, M.; Fehrmann, H.; Fejer, M. M.; Fenyvesi, E.; Ferrante, I.; Ferreira, E. C.; Ferrini, F.; Fidecaro, F.; Fiori, I.; Fiorucci, D.; Fisher, R. P.; Flaminio, R.; Fletcher, M; Fournier, J. -D.; Frasca, S.; Frasconi, F.; Frei, Z.; Freise, A.; Frey, R.; Frey, V.; Fritschel, P.; Frolov, V. V.; Fulda, P.; Fyffe, M.; Gabbard, H. A. G.; Gair, J. R.; Gammaitoni, L.; Gaonkar, S. G.; Garufi, F.; Gaur, G.; Gehrels, N.; Gemme, G.; Geng, P.; Genin, E.; Gennai, A.; George, J.; Gergely, L.; Germain, V.; Ghosh, Abhirup; Ghosh, Archisman; Ghosh, S.; Giaime, J. A.; Giardina, K. D.; Giazotto, A.; Gill, K.P.; Glaefke, A.; Goetz, E.; Goetz, R.; Gondan, L.; Gonzalez, Idelmis G.; Castro, J. M. Gonzalez; Gopakumar, A.; Gordon, N. A.; Gorodetsky, M. L.; Gossan, S. E.; Lee-Gosselin, M.; Gouaty, R.; Grado, A.; Graef, C.; Graff, P. B.; Granata, M.; Grant, A.; Gras, S.; Gray, C.M.; Greco, G.; Green, A. C.; Groot, P.; Grote, H.; Grunewald, S.; Guidi, G. M.; Guo, X.; Gupta, A.; Gupta, M. K.; Gushwa, K. E.; Gustafson, E. K.; Gustafson, R.; Hacker, J. J.; Buffoni-Hall, R.; Hall, E. D.; Hammond, G.L.; Haney, M.; Hanke, M. M.; Hanks, J.; Hanna, C.; Hanson, P.J.; Hardwick, T.; Harms, J.; Harry, G. M.; Harry, I. W.; Hart, M. J.; Hartman, M. T.; Haster, C. -J.; Haughian, K.; Heidmann, A.; Heintze, M. C.; Heitmann, H.; Hello, P.; Hemming, G.; Hendry, M.; Heng, I. S.; Hennig, J.; Henry, J.A.; Heptonstall, A. W.; Heurs, M.; Hild, S.; Hoak, D.; Hofman, D.; Holt, K.; Holz, D. E.; Hopkins, P.; Hough, J.; Houston, E. A.; Howell, E. J.; Hu, Y. M.; Huang, S.; Huerta, E. A.; Huet, D.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh-Dinh, T.; Indik, N.; Ingram, D. R.; Inta, R.; Isa, H. N.; Isac, J. -M.; Isi, M.; Isogai, T.; Iyer, B. R.; Izumi, K.; Jacqmin, T.; Jang, D.H.; Jani, K.; Jaranowski, P.; Jawahar, S.; Jian, L.; Jimenez-Forteza, F.; Johnson, W.; Jones, I.D.; Jones, R.; Jonker, R. J. G.; Ju, L.; Haris, K.; Kalaghatgi, C. V.; Kalogera, V.; Kandhasamy, S.; Kang, G.H.; Kanner, J. B.; Kapadia, S. J.; Karki, S.; Karvinen, K. S.; Kasprzack, M.; Katsavounidis, E.; Katzman, W.; Kaufer, S.; Kaur, T.; Kawabe, K.; Kefelian, F.; Kehl, M. S.; Keitel, D.; Kelley, D. B.; Kells, W.; Kennedy, R.E.; Key, J. S.; Khalili, F. Y.; Khan, I.; Khan., S.; Khan, Z.; Khazanov, E. A.; Kijbunchoo, N.; Kim, Chi-Woong; Kim, Chunglee; Kim, J.; Kim, K.; Kim, Namjun; Kim, W.; Kim, Y.M.; Kimbrell, S. J.; King, E. J.; King, P. J.; Kissel, J. S.; Klein, B.; Kleybolte, L.; Klimenko, S.; Koehlenbeck, S. M.; Koley, S.; Kondrashov, V.; Kontos, A.; Korobko, M.; Korth, W. Z.; Kowalska, I.; Kozak, D. B.; Kringel, V.; Krishnan, B.; Krolak, A.; Krueger, C.; Kuehn, G.; Kumar, P.; Kumar, R.; Kuo, L.; Kutynia, A.; Lackey, B. D.; Landry, M.; Lange, J.; Lantz, B.; Lasky, P. D.; Laxen, M.; Lazzaro, C.; Leaci, P.; Leavey, S.; Lebigot, E. O.; Lee, C.H.; Lee, K.H.; Lee, M.H.; Lee, K.; Lenon, A.; Leonardi, M.; Leong, J. R.; Leroy, N.; Letendre, N.; Levin, Y.; Lewis, J. B.; Li, T. G. F.; Libson, A.; Littenberg, T. B.; Lockerbie, N. A.; Lombardi, A. L.; London, L. T.; Lord, J. E.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Lough, J. D.; Lueck, H.; Lundgren, A. P.; Lynch, R.; Ma, Y.; Machenschalk, B.; MacInnis, M.; Macleod, D. M.; Magana-Sandoval, F.; Zertuche, L. Magana; Magee, R. M.; Majorana, E.; Maksimovic, I.; Malvezzi, V.; Man, N.; Mandic, V.; Mangano, V.; Mansell, G. L.; Manske, M.; Mantovani, M.; Marchesoni, F.; Marion, F.; Marka, S.; Marka, Z.; Markosyan, A. S.; Maros, E.; Martelli, F.; Martellini, L.; Martin, I. W.; Martynov, D. V.; Marx, J. N.; Mason, K.; Masserot, A.; Massinger, T. J.; Masso-Reid, M.; Mastrogiovanni, S.; Matichard, F.; Matone, L.; Mavalvala, N.; Mazumder, N.; McCarthy, R.; McClelland, D. E.; McCormick, S.; McGuire, S. C.; McIntyre, G.; McIver, J.; McManus, D. J.; McRae, T.; McWilliams, S. T.; Meacher, D.; Meadors, G. D.; Meidam, J.; Melatos, A.; Mendell, G.; Mercer, R. A.; Merilh, E. L.; Merzougui, M.; Meshkov, S.; Messenger, C.; Messick, C.; Metzdorff, R.; Meyers, P. M.; Mezzani, F.; Miao, H.; Michel, C.; Middleton, H.; Mikhailov, E. E.; Milano, L.; Miller, A. L.; Miller, A. L.; Miller, B.; Miller, J.; Millhouse, M.; Minenkov, Y.; Ming, J.; Mirshekari, S.; Mishra, C.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Moggi, A.; Mohan, M.; Mohapatra, S. R. P.; Montani, M.; Moore, B.C.; Moore, J.C.; Moraru, D.; Gutierrez Moreno, M.; Morriss, S. R.; Mossavi, K.; Mours, B.; Mow-Lowry, C. M.; Mueller, G.; Muir, A. W.; Mukherjee, Arunava; Mukherjee, S.D.; Mukherjee, S.; Mukund, N.; Mullavey, A.; Munch, J.; Murphy, D. J.; Murray, P.G.; Mytidis, A.; Nardecchia, I.; Naticchioni, L.; Nayak, R. K.; Nedkova, K.; Nelemans, G.; Nelson, T. J. N.; Gutierrez-Neri, M.; Neunzert, A.; Newton-Howes, G.; Nguyen, T. T.; Nielsen, A. B.; Nissanke, S.; Nitz, A.; Nocera, F.; Nolting, D.; Normandin, M. E. N.; Nuttall, L. K.; Oberling, J.; Ochsner, E.; O'Dell, J.; Oelker, E.; Ogin, G. H.; Oh, J.; Oh, S. H.; Ohme, F.; Oliver, M. B.; Oppermann, P.; Oram, Richard J.; O'Reilly, B.; O'Shaughnessy, R.; Ottaway, D. J.; Overmier, H.; Owen, B. J.; Pai, A.; Pai, S. A.; Palamos, J. R.; Palashov, O.; Palomba, C.; Pal-Singh, A.; Pan, H.; Pankow, C.; Pannarale, F.; Pant, B. C.; Paoletti, F.; Paoli, A.; Papa, M. A.; Paris, H. R.; Parker, W.S; Pascucci, D.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Patel, P.; Patricelli, B.; Patrick, Z.; Pearlstone, B. L.; Pedraza, M.; Pedurand, R.; Pekowsky, L.; Pele, A.; Penn, S.; Perreca, A.; Perri, L. M.; Phelps, M.; Piccinni, O. J.; Pichot, M.; Piergiovanni, F.; Pierro, V.; Pillant, G.; Pinard, L.; Pinto, I. M.; Pitkin, M.; Poe, M.; Poggiani, R.; Popolizio, P.; Post, A.; Powell, J.; Prasad, J.; Predoi, V.; Prestegard, T.; Price, L. R.; Prijatelj, M.; Principe, M.; Privitera, S.; Prix, R.; Prodi, G. A.; Prokhorov, L. G.; Puncken, O.; Punturo, M.; Puppo, P.; Puerrer, M.; Qi, H.; Qin, J.; Qiu, S.; Quetschke, V.; Quintero, E. A.; Quitzow-James, R.; Raab, F. J.; Rabeling, D. S.; Radkins, H.; Raffai, P.; Raja, S.; Rajan, C.; Rakhmanov, M.; Rapagnani, P.; Raymond, V.; Razzano, M.; Re, V.; Read, J.; Reed, C. M.; Regimbau, T.; Rei, L.; Reid, S.; Reitze, D. H.; Rew, H.; Reyes, S. D.; Ricci, F.; Riles, K.; Rizzo, D.M.; Robertson, N. A.; Robie, R.; Robinet, F.; Rocchi, A.; Rolland, L.; Rollins, J. G.; Roma, V. J.; Romano, R.; Romanov, G.; Romie, J. H.; Rosinska, D.; Rowan, S.; Ruediger, A.; Ruggi, P.; Ryan, K.A.; Sachdev, Perminder S; Sadecki, T.; Sadeghian, L.; Sakellariadou, M.; Salconi, L.; Saleem, M.; Salemi, F.; Samajdar, A.; Sammut, L.; Sanchez, E. J.; Sandberg, V.; Sandeen, B.; Sanders, J. R.; Sassolas, B.; Saulson, P. R.; Sauter, O. E. S.; Savage, R. L.; Sawadsky, A.; Schale, P.; Schilling, R.; Schmidt, J; Schmidt, P.; Schnabel, R.B.; Schofield, R. M. S.; Schoebeck, A.; Schreiber, K.E.C.; Schuette, D.; Schutz, B. F.; Scott, J.; Scott, M.S.; Sellers, D.; Sengupta, A. S.; Sentenac, D.; Sequino, V.; Sergeev, A.; Setyawati, Y.; Shaddock, D. A.; Shaffer, T. J.; Shahriar, M. S.; Shaltev, M.; Shapiro, B.; Shawhan, P.; Sheperd, A.; Shoemaker, D. H.; Shoemaker, D. M.; Siellez, K.; Siemens, X.; Sieniawska, M.; Sigg, D.; Silva, António Dias da; Singer, A; Singer, L. P.; Singh, A.; Singh, R.; Singhal, A.; Sintes, A. M.; Slagmolen, B. J. J.; Smith, R. J. E.; Smith, N.D.; Smith, R. J. E.; Son, E. J.; Sorazu, B.; Sorrentino, F.; Souradeep, T.; Srivastava, A. K.; Staley, A.; Steinke, M.; Steinlechner, J.; Steinlechner, S.; Steinmeyer, D.; Stephens, B. C.; Stone, J.R.; Strain, K. A.; Straniero, N.; Stratta, G.; Strauss, N. A.; Strigin, S. E.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Sun, L.; Sunil, S.; Sutton, P. J.; Swinkels, B. L.; Szczepanczyk, M. J.; Tacca, M.D.; Talukder, D.; Tanner, D. B.; Tapai, M.; Tarabrin, S. P.; Taracchini, A.; Taylor, W.R.; Theeg, T.; Thirugnanasambandam, M. P.; Thomas, E. G.; Thomas, M.; Thomas, P.; Thorne, K. A.; Thrane, E.; Tiwari, S.; Tiwari, V.; Tokmakov, K. V.; Toland, K.; Tomlinson, C.; Tonelli, M.; Tornasi, Z.; Torres, C. V.; Torrie, C. I.; Toyra, D.; Travasso, F.; Traylor, G.; Trifiro, D.; Tringali, M. C.; Trozzo, L.; Tse, M.; Turconi, M.; Tuyenbayev, D.; Ugolini, D.; Unnikrishnan, C. S.; Urban, A. L.; Usman, S. A.; Vahlbruch, H.; Vajente, G.; Valdes, G.; van Bakel, N.; Van Beuzekom, Martin; van den Brand, J. F. J.; Van Den Broeck, C.F.F.; Vander-Hyde, D. C.; van der Schaaf, L.; van Heijningen, J. V.; van Veggel, A. A.; Vardaro, M.; Vass, S.; Vasuth, M.; Vaulin, R.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P.J.; Venkateswara, K.; Verkindt, D.; Vetrano, F.; Vicere, A.; Vinciguerra, S.; Vine, D. J.; Vinet, J. -Y.; Vitale, S.; Vo, T.; Vocca, H.; Vorvick, C.; Voss, D. V.; Vousden, W. D.; Vyatchanin, S. P.; Wade, A. R.; Wade, L. E.; Wade, MT; Walker, M.; Wallace, L.; Walsh, S.; Wang, G.; Wang, H.; Wang, M.; Wang, X.; Wang, Y.; Ward, R. L.; Warner, J.; Was, M.; Weaver, B.; Wei, L. -W.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Wen, L.M.; Wessels, P.; Westphal, T.; Wette, K.; Whelan, J. T.; Whiting, B. F.; Williams, D.R.; Williamson, A. R.; Willis, J. L.; Willke, B.; Wimmer, M. H.; Winkler, W.; Wipf, C. C.; Wittel, H.; Woan, G.; Woehler, J.; Worden, J.; Wright, J.L.; Wu, D.S.; Wu, G.; Yablon, J.; Yam, W.; Yamamoto, H.; Yancey, C. C.; Yu, H.; Yvert, M.; Zadrozny, A.; Zangrando, L.; Zanolin, M.; Zendri, J. -P.; Zevin, M.; Zhang, L.; Zhang, M.; Zhang, Y.; Zhao, C.; Zhou, M.; Zhou, Z.; Zhu, X. J.; Zucker, M. E.; Zuraw, S. E.; Zweizig, J.; Sigurdsson, S.

2017-01-01

We describe a directed search for continuous gravitational waves in data from the sixth initial LIGO science run. The target was the nearby globular cluster NGC 6544 at a distance of approximate to 2.7 kpc. The search covered a broad band of frequencies along with first and second frequency

A fast pulsar candidate in the globular cluster M28

International Nuclear Information System (INIS)

Mahoney, M.J.; Erickson, W.C.

1985-01-01

Recent work on radio sources in globular clusters, using the very large Array telescope at 1,465 MHz, revealed a source within the core of M28. Observations of this source at 30.9 and 57.5 MHz have also been carried out, by the authors, using the Clark lake TPT synthesis telescope. The observations show that the source has a spectral index of -2.44. Only pulsars have well-documented spectra which are as steep as this. (U.K.)

Three Ancient Halo Subgiants: Precise Parallaxes, Compositions, Ages, and Implications for Globular Clusters

DEFF Research Database (Denmark)

VandenBerg, Don A.; Bond, Howard E.; Nelan, Edmund P.

2014-01-01

very soon after the Big Bang. (Stellar models that neglect diffusive processes seem to be ruled out as they would predict that HD 140283 is ~1.5 Gyr older than the universe.) The field halo subgiants appear to be older than globular clusters of similar metallicities: if distances close to those implied...

Consumo e digestibilidade de novilhos Nelore sob pastagem suplementados com misturas múltiplas Intake and digestibility of Nelore steers grazing pasture and supplemented with multiple mixture

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L.O.F. Oliveira

2004-02-01

Full Text Available Estudou-se o efeito da suplementação com misturas múltiplas sobre o consumo, digestibilidade e desempenho de novilhos Nelore, em pastagens de Brachiaria brizantha Cv. Marandu, submetidos a quatro tratamentos. No tratamento um (T1, cada animal recebeu 800g/dia de suplemento contendo uréia como fonte de nitrogênio não protéico (NNP; no tratamento dois (T2, recebeu 800g/dia de mistura na qual a uréia foi substituída por amiréia como fonte de NNP; no tratamento três (T3, recebeu 1500g/dia de uma mistura com amiréia; e no tratamento quatro (T4= controle, recebeu sal mineral. Seis animais por tratamento foram utilizados para se medir o consumo pela técnica de indicador externo (óxido crômico, e 10 animais foram usados na avaliação de ganho de peso. Foram utilizados dois animais canulados no esôfago para coleta de amostra de extrusa. Os animais suplementados obtiveram ganhos de peso superiores (PThe effect of three multiple mixtures supplementation on intake, digestibility and performance of Nelore steers grazing pasture of Brachiaria decumbens CV Marandu was studied. The multiple mixtures (treatments - T were defined as: T1 - 800g of supplement with urea as crude protein source, T2 - 800g of mixture in which urea was replaced by starea, T3 - 1500g of starea, and T4 - mineral salt fed ad libitum as a control group. Six animals per treatment were given chromic oxide as a marker to measure intake and 10 animals per treatment were used to evaluate their performance. Two esophageal fistulated steers were used to collect samples of extruse. The animals fed on supplement diets showed higher weight gains (335, 419, 467g/animal than those from the control group (271g/animal. Dry matter digestibility were 56.7, 49.8, 48.9 and 45.5%, respectively, for T1, T2, T3 and T4. A positive correlation between dry matter digestibility and in vitro dry matter digestibility (P<0.05 was observed. Supplementation with multiple mixtures increased dry matter

ON THE SERENDIPITOUS DISCOVERY OF A Li-RICH GIANT IN THE GLOBULAR CLUSTER NGC 362

Energy Technology Data Exchange (ETDEWEB)

D’Orazi, Valentina; Gratton, Raffaele G.; Lucatello, Sara; Momany, Yazan [INAF—Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, I-35122, Padova (Italy); Angelou, George C. [Max Planck Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, D-37077 Göttingen (Germany); Bragaglia, Angela; Carretta, Eugenio; Sollima, Antonio [INAF—Osservatorio Astronomico di Bologna, via Ranzani 1, I-40127, Bologna (Italy); Lattanzio, John C., E-mail: valentina.dorazi@oapd.inaf.it [Monash Centre for Astrophysics (MoCA), Monash University, Melbourne, VIC 3800 (Australia)

2015-03-10

We have serendipitously identified the first lithium-rich giant star located close to the red giant branch bump in a globular cluster. Through intermediate-resolution FLAMES spectra we derived a lithium abundance of A(Li) = 2.55 (assuming local thermodynamical equilibrium), which is extremely high considering the star’s evolutionary stage. Kinematic and photometric analysis confirm the object as a member of the globular cluster NGC 362. This is the fourth Li-rich giant discovered in a globular cluster, but is the only one known to exist at a luminosity close to the bump magnitude. The three previous detections are clearly more evolved, located close to, or beyond, the tip of their red giant branch. Our observations are able to discard the accretion of planets/brown dwarfs, as well as an enhanced mass-loss mechanism as a formation channel for this rare object. While the star sits just above the cluster bump luminosity, its temperature places it toward the blue side of the giant branch in the color–magnitude diagram. We require further dedicated observations to unambiguously identify the star as a red giant: we are currently unable to confirm whether Li production has occurred at the bump of the luminosity function or if the star is on the pre-zero-age horizontal branch. The latter scenario provides the opportunity for the star to have synthesized Li rapidly during the core helium flash or gradually during its red giant branch ascent via some extra mixing process.

Suco de uva enriquecido com soro: elaboração e aceitabilidade sensorial

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Simone Vilela Talma

2010-04-01

Full Text Available Estudos têm sido realizados em diversos países visando oferecer ao mercado novas formas de utilização do soro de leite. O objetivo deste trabalho foi desenvolver suco de uva enriquecido com soro lácteo e avaliar a aceitação sensorial utilizando a escala hedônica facial e a técnica Mapa de Preferência. As diferentes formulações foram avaliadas por 111 crianças com idade entre 7 e 11 anos, no período de setembro a novembro de 2009, em uma escola pública do município de Rio Pomba, MG. Para o preparo da bebida foram adicionados 250 mL de suco de uva concentrado em 1750 mL da mistura de água e soro nas proporções de 40%, 60%, 80% e 100% de soro e 7% de açúcar. As amostras que continham 40% e 60% de soro na mistura de água e soro foram classificadas pelas crianças entre os termos hedônicos "gostei extremamente" e "gostei moderadamente", respectivamente, indicando a boa aceitação pela maioria dos consumidores. Entretanto, do total de provadores, 44 classificaram a amostra contendo 100% de soro na mistura entre os termos hedônicos "desgostei moderadamente" e "desgostei extremamente" indicando rejeição.

Another non-segregated Blue Straggler population in a globular cluster: the case of NGC 2419.

Science.gov (United States)

Dalessandro, E.; Lanzoni, B.; Ferraro, F. R.; Vespe, F.; Bellazzini, M.; Rood, R. T.

We have used a combination of ACS-HST high-resolution and wide-field SUBARU data in order to study the Blue Straggler Star (BSS) population over the entire extension of the remote Galactic globular cluster NGC 2419. The radial distribution of the selected BSS is the same as that of the other cluster stars. In this sense the BSS radial distribution is like that of omega Centauri and unlike that of all Galactic globular clusters studied to date, which have highly centrally segregated distributions and in most cases a pronounced upturn in the external regions. As in the case of omega Centauri, this evidence indicates that NGC 2419 is not yet relaxed even in the central regions. This observational fact is in agreement with estimated half-mass relaxation time, which is of the order of the cluster age.

Giant Rapid X-ray Flares in Extragalactic Globular Clusters

Science.gov (United States)

Irwin, Jimmy

2018-01-01

There is only one known class of non-destructive, highly energetic astrophysical object in the Universe whose energy emission varies by more than a factor of 100 on time scales of less than a minute -- soft gamma repeaters/anomalous X-ray pulsars, whose flares are believed to be caused by the energy release from the cracking of a neutron star's surface by very strong magnetic fields. All other known violent, rapid explosions, including gamma-ray bursts and supernovae, are believed to destroy the object in the process. Here, we report the discovery of a second class of non-destructive, highly energetic rapidly flaring X-ray object located within two nearby galaxies with fundamentally different properties than soft gamma repeaters/anomalous X-ray pulsars. One source is located within a suspected globular cluster of the host galaxy and flared one time, while the other source is located in either a globular cluster of the host galaxy or the core of a stripped dwarf companion galaxy that flared on six occasions over a seven year time span. When not flaring, the sources appear as normal accreting neutron star or black hole X-ray binaries, indicating that the flare event does not significantly disrupt the host system. While the nature of these sources is still unclear, the discovery of these sources in decade-old archival Chandra X-ray Observatory data illustrates the under-utilization of X-ray timing as a means to discover new classes of explosive events in the Universe.

SPACE VELOCITIES OF SOUTHERN GLOBULAR CLUSTERS. VII. NGC 6397, NGC 6626 (M28), AND NGC 6656 (M22)

Energy Technology Data Exchange (ETDEWEB)

Casetti-Dinescu, Dana I.; Girard, Terrence M.; Van Altena, William F. [Astronomy Department, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States); Jilkova, Lucie [Department of Theoretical Physics and Astrophysics, Faculty of Science, Masaryk University, Kotlarska 2, CZ-61137 Brno (Czech Republic); Podesta, Federico; Lopez, Carlos E., E-mail: dana.casetti@yale.edu, E-mail: terry.girard@yale.edu, E-mail: william.vanaltena@yale.edu, E-mail: jilkoval@physics.muni.cz [Universidad National de San Juan, Observatorio Astronomico ' ' Felix Aguilar' ' and Yale Southern Observatory, Chimbas, 5413 San Juan (Argentina)

2013-08-01

We have measured the absolute proper motions of globular clusters NGC 6397, NGC 6626 (M22), and NGC 6656 (M28) as part of our ongoing Southern Proper-Motion Program. The reference system is the ICRS via Hipparcos stars for these three low-Galactic-latitude clusters. Formal errors range between {approx}0.3 and 0.7 mas yr{sup -1}. Notable is the result for NGC 6397, which differs by 2.5 mas yr{sup -1} from two Hubble Space Telescope determinations while agreeing with previous ground-based ones. We determine orbits for all three clusters in an axisymmetric and barred model of the Galaxy and discuss these in the context of globular-cluster formation. M22 is a well-known cluster with an iron abundance spread; such clusters are now believed to have formed in massive parent systems that can retain ejecta of core-collapsed supernovae. We find that the five currently accepted globular clusters with iron/calcium abundance spread show orbits unrelated to each other, thus suggesting at least five independent, massive progenitors that have contributed to the build-up of the Milky-Way halo.

Avaliação do comportamento hidrodinâmico de reator anaeróbio de manta de lodo e fluxo ascendente com diferentes configurações do sistema de distribuição do afluente utilizando fluidodinâmica computacional

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Diego Bongiorno Cruz

Full Text Available RESUMO Compreender o comportamento hidrodinâmico de reatores biológicos pode auxiliar na detecção de problemas associados a falhas operacionais e de projeto, situações que prejudicam a eficiência do tratamento. Neste artigo, realizaram-se simulações da fluidodinâmica computacional (CFD de escoamento de duas fases sólida-líquida de um reator anaeróbio de manta de lodo e fluxo ascendente (UASB, em escala piloto (160 L, com tempo de detenção hidráulica (TDH de 10 h e vazão de 16 L.h-1. Um modelo Euler-Euler simplificado foi formulado para simular o comportamento hidrodinâmico da zona de reação, influenciada pela configuração do sistema de distribuição do afluente. Foram avaliadas quatro configurações do sistema de distribuição do afluente no reator: uma entrada na parte central (1 e duas entradas centrais (2, de fluxo ascendente; duas entradas nas laterais (3, de fluxo radial; e três entradas de fluxo descendente (4, utilizando geometrias bidimensionais e tridimensionais para verificar a formação de zonas mortas, curtos-circuitos hidráulicos e caminhos preferenciais. As melhores características hidrodinâmicas e a melhor distribuição do afluente foram verificadas na configuração 4, com melhor perfil de mistura do lodo com a fase líquida, na comparação com as demais configurações. Foi notada formação de vórtices na parte inferior do reator com maior concentração do lodo anaeróbio nessa configuração e de caminhos preferenciais nas laterais do reator na configuração 3, indicando mistura ineficiente do afluente com o lodo anaeróbio. O modelo demonstrou que a configuração do sistema de distribuição do afluente influencia significativamente o comportamento hidrodinâmico do reator UASB.

Effect of a low-frequency magnetic field on the structure of globular blood proteins

Science.gov (United States)

Zalesskaya, G. A.; Ulashchik, V. S.; Mit'kovskaya, N. P.; Laskina, O. V.; Kuchinskii, A. V.

2007-09-01

We used IR Fourier absorption spectra of blood to study changes in the structure of globular blood proteins with extracorporeal autohemomagnetotherapy, used to treat ischemic heart disease. We compare the spectra of blood before and after magnetotherapy in the regions: amide I (1655 cm-1), amide II (1545 cm-1), amide III (1230-1350 cm-1), amide IV and amide V (400-700 cm-1). We have shown that pronounced changes in the spectra in the indicated regions on direct exposure of blood in vivo to a low-frequency pulsed magnetic field are connected with conformational changes in the secondary structure of globular blood proteins, which are apparent in the increase in the contribution of the α-helix conformation. We discuss the magnetotherapy-initiated appearance of new IR absorption bands at 1018 and 1038 cm-1 and an increase in the intensity of a number of other bands located in the 1000-1200 cm-1 region, which suggests a change in the concentration of some blood components.

Chemical Abundances of Red Giant Branch Stars in the Globular Cluster NGC 288

Science.gov (United States)

Hsyu, Tiffany; Johnson, C. I.; Pilachowski, C. A.; Lee, Y.; Rich, R. M.

2013-01-01

We present chemical abundances and radial velocities for ~30 red giant branch (RGB) stars in the globular cluster NGC 288. The results are based on moderate resolution (R≈18,000) and moderate signal-to-noise ratio 50-75) obtained with the Hydra multi-object spectrograph on the Blanco 4m telescope. NGC 288 has been shown to exhibit two separate RGBs and we investigate possible differences in metallicity and/or light element abundances between stars on each branch. We present a new filter tracing for the CTIO Calcium HK narrow band filter and explore its effects on previous globular cluster color-magnitude diagrams. We also compare the light element abundance patterns of NGC 288 to those of other similar metallicity halo clusters. This material is based upon work supported by the National Science Foundation under award No.AST-1003201 to C.I.J. C.A.P. gratefully acknowledges support from the Daniel Kirkwood Research Fund at Indiana University. R.M.R. acknowledges support from NSF grants AST-0709479 and AST-121120995.

Effects of main-sequence mass loss on the turnoff ages of globular clusters

International Nuclear Information System (INIS)

Guzik, J.A.

1989-01-01

Willson, Bowen, and Struck-Marcell have proposed that globular cluster main-sequence turnoff ages can be reconciled with the lower ages of the Galaxy and universe deduced from other methods by incorporating an epoch of early main-sequence mass-loss by stars of spectral types A through early-F. The proposed mass loss is pulsation-driven, and facilitated by rapid rotation. This paper presents stellar evolution calculations of Pop. II (Z = 0.001) mass-losing stars of initial mass 0.8 to 1.6 M circle dot , with exponentially-decreasing mass loss rates of e-folding times 0.5 to 2.0 Gyr, evolving to a final mass of 0.7 M circle dot . The calculations indicate that a globular cluster with apparent turnoff age 18 Gyr could have an actual age as low as ∼12 Gyr. Observational implications that may help to verify the hypothesis, e.g. low C/N abundance ratios among red giants following first dredge-up, blue stragglers, red giant deficiencies, and signatures in cluster mass/luminosity functions, are also discussed.25 refs., 4 figs., 3 tabs

VizieR Online Data Catalog: Tidal radii of 7 globular clusters (Lehmann+ 1997)

Science.gov (United States)

Lehmann, I.; Scholz, R.-D.

1998-02-01

We present new tidal radii for seven Galactic globular clusters using the method of automated star counts on Schmidt plates of the Tautenburg, Palomar and UK telescopes. The plates were fully scanned with the APM system in Cambridge (UK). Special account was given to a reliable background subtraction and the correction of crowding effects in the central cluster region. For the latter we used a new kind of crowding correction based on a statistical approach to the distribution of stellar images and the luminosity function of the cluster stars in the uncrowded area. The star counts were correlated with surface brightness profiles of different authors to obtain complete projected density profiles of the globular clusters. Fitting an empirical density law (King 1962AJ.....67..471K) we derived the following structural parameters: tidal radius rt, core radius rc and concentration parameter c. In the cases of NGC 5466, M 5, M 12, M 13 and M 15 we found an indication for a tidal tail around these objects (cf. Grillmair et al., 1995AJ....109.2553G). (1 data file).

LISA Sources in Milky Way Globular Clusters

Science.gov (United States)

Kremer, Kyle; Chatterjee, Sourav; Breivik, Katelyn; Rodriguez, Carl L.; Larson, Shane L.; Rasio, Frederic A.

2018-05-01

We explore the formation of double-compact-object binaries in Milky Way (MW) globular clusters (GCs) that may be detectable by the Laser Interferometer Space Antenna (LISA). We use a set of 137 fully evolved GC models that, overall, effectively match the properties of the observed GCs in the MW. We estimate that, in total, the MW GCs contain ˜21 sources that will be detectable by LISA. These detectable sources contain all combinations of black hole (BH), neutron star, and white dwarf components. We predict ˜7 of these sources will be BH-BH binaries. Furthermore, we show that some of these BH-BH binaries can have signal-to-noise ratios large enough to be detectable at the distance of the Andromeda galaxy or even the Virgo cluster.

Uso de EVA Modificado com Grupos Mercaptana na Compatibilização de Misturas NBR/EPDM The Use of Mercapto-Modified EVA as Compatibilizing Agent for NBR/EPDM Blends

Directory of Open Access Journals (Sweden)

Marcia G. Oliveira

2002-10-01

Full Text Available Copolímeros de etileno - acetato de vinila com diferentes teores de acetato de vinila - foram funcionalizados com grupos mercaptana e utilizados como agentes compatibilizantes reativos em misturas envolvendo borracha nitrílica e copolímeros de etileno-propileno-dieno (EPDM. Foi investigada a influência das características estruturais dos copolímeros funcionalizados no processo de vulcanização, propriedades mecânicas e dinâmico-mecânicas bem como resistência ao envelhecimento. A adição de pequena porção desses copolímeros resultou em tempos de cura menores. Copolímeros funcionalizados, obtidos a partir da transesterificação de EVA com ácido mercaptoacético (EVASH, apresentaram desempenho melhor como compatibilizante do que aquele obtido a partir da esterificação de EVA hidrolisado com o mesmo ácido (EVALSH. As misturas compatibilizadas com o primeiro sistema apresentaram melhores propriedades mecânicas além de uma morfologia mais refinada e uniforme. A presença dos grupos mercaptana nesses agentes compatibilizantes resultou em uma melhora na resistência ao envelhecimento das misturas.Ethylene-vinyl acetate (EVA copolymers with different amounts of vinyl acetate have been functionalized with mercapto groups and these reactive compounds were used as compatibilizing agent for nitrile rubber (NBR/ ethylene-propylene-diene rubber (EPDM blends. The effects from the structural properties of mercapto-modified EVA compounds on the vulcanizing characteristics, mechanical properties, aging resistance and dynamic-mechanical properties were investigated. The addition of low amounts of mercapto-modified EVA resulted in a decrease of curing time. The functionalized copolymer obtained through transesterification reaction between mercaptoacetic acid and EVA (EVASH presented better compatibilizing action than that obtained from esterification of hydrolyzed EVA and mercaptoacetic acid (EVALSH. Blends compatibilized with the former

Estabilidade da pré-mistura de bolo elaborada com 60% de farinha de banana verde Stability of cake pre-mixture made with 60% of green banana flour

Directory of Open Access Journals (Sweden)

Antonia de Maria Borges

2010-02-01

Full Text Available Objetivou-se, neste trabalho, avaliar a estabilidade físico-química e microbiológica da pré-mistura de bolo elaborada com 60% de farinha de banana em substituição à farinha de trigo, durante 120 dias de armazenamento. O delineamento experimental utilizado foi o inteiramente casualizado, com cinco tratamentos (tempo de armazenamento - 0, 30, 60, 90 e 120 dias e cinco repetições. Durante o armazenamento, a cada 30 dias foram realizadas as determinações de umidade, pH, acidez total titulável (ATT, vitamina C, coliformes a 45ºC, Bacillus cereus, Salmonella sp., fungos filamentosos e leveduras. A avaliação físico-química da pré-mistura manteve suas características com pequenas variações durante o armazenamento em temperatura ambiente. A variação mais expressiva foi observada quanto aos parâmetros pH e ATT. A pré-mistura não apresentou alterações durante o armazenamento com relação ao desenvolvimento dos patógenos: coliformes a 45ºC, Bacillus cereus, Salmonella sp., fungos filamentosos e leveduras.The objective of work was to evaluate the physicochemical and microbiological stability of a cake pre-mixture made with 60% of green banana flour instead of wheat flour during a storage period of 120 days. The experimental delineation utilized was entirely randomized, with 5 treatments (time of storage - 0, 30, 60, 90 and 120 days and 5 repetitions. During storage, the following determinations were made for each 30-day period: moisture, pH, total titratable acidity (TTA, vitamin C, coliforms at 45ºC, Bacillus cereus, Salmonella sp., filamentous fungi and yeasts. The physical-chemical evaluation showed that the pre-mixture kept its characteristics with small variations during storage at room temperature. The most expressive variation was observed in the pH and TTA parameters. The pre-mixture remained without alterations during the storage with regard to the growth of the pathogens: coliforms at 45ºC, Bacillus cereus

THE INFLUENCE OF POTASSIUM DICHROMATE Cr (VI ADMINISTRATION DURATION ON GLOBULAR RESISTANCE IN FEMALE RATS

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LETIŢIA STANA

2009-05-01

Full Text Available The „in vivo” experiment has had as aim the study of different Cr(VI doses administration on globular resistance in female rats related to administration duration. Study was carried out on 56 female rats divided in 8 groups, 6 experimental and 2 control that received potassium dichromate in drinking water in doses of 25 ppm, 50 ppm and 75ppm Cr(VI, for 3 months, respectively, 6 months. Decrease of globular resistance (in terms of haemolysis degree in hypotonic solutions at increasing dose (up to 0.8% NaCl at 75 ppm dose in all experimental groups, in direct relation with the duration of administration was registered. Control groups were in physiological limits. The results of the present study revealed the affecting of erythrocyte membrane in function of administration duration and chromium intake level, because of oxidative lesions produced by it.

Comportamento geotécnico de misturas granulométricas de solo-grits Mechanical behavior of the differents soil-grits granulometrics mixtures

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Carlos Cardoso Machado

2009-06-01

Full Text Available Neste artigo, analisa-se a influência das diversas frações granulométricas do resíduo grits nos parâmetros ótimos de compactação, resistência mecânica e expansão, quando em misturas com dois solos típicos da Zona da Mata Norte de Minas Gerais, Brasil, com fins de aplicação em estradas florestais. Os teores de resíduo empregados nas misturas foram de 4, 8, 12, 16, 20, 24 e 28%, em relação à massa seca de solos, trabalhando-se com as energias de compactação dos ensaios Proctor intermediário e modificado. As frações de resíduo estudadas foram as equivalentes à argila e silte (d This paper addresses the influence of size distribution of the industrial waste named grits on the optimum compaction parameters, mechanical strength and swelling of two typical soils from the North Forest Zone of Minas Gerais State, Brazil, for forest road applications. Specimens compacted at the intermediate and modified Proctor compaction effort and waste contents of 4, 8, 12, 16, 20, 24 and 28 % regarding soil dry unit weights were used throughout the study. Waste sizes analyzed in the laboratory testing program were those equivalent to clay (d 2 mm and gravel (2 mm < d < 76 mm sizes in accordance to the DNIT technical standard (DNIT, 1996. Soils and mixtures bearing capacity and swelling were evaluated by the CBR test. Data from the laboratory testing program support that the waste's clay and gravel size portions were responsible, respectively, for higher and lower increases in soils bearing capacity.

The Age of the Inner Halo Globular Cluster NGC 6652

OpenAIRE

Chaboyer, Brian; Sarajedini, Ata; Armandroff, Taft E.

2000-01-01

HST (V,I) photometry has been obtained for the inner halo globular cluster NGC 6652. The photometry reaches approximately 4 mag below the turn-off and includes a well populated horizontal branch. This cluster is located close to the Galactic center at a galactocentric distance of approximately 2.0 kpc with a reddening of E(V-I) = 0.15 +/- 0.02 and has a metallicity of [Fe/H] approximately -0.85. Based upon Delta(V) between the point on the sub-giant branch which is 0.05 mag redder than the tu...

Fukuyoa paulensis gen. et sp. nov., a new genus for the globular species of the dinoflagellate Gambierdiscus (Dinophyceae.

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Fernando Gómez

Full Text Available The marine epiphytic dinoflagellate Gambierdiscus is a toxicologically important genus responsible for ciguatera fish poisoning, the principal cause of non-bacterial illness associated with fish consumption. The genus currently contains species exhibiting either globular or anterior-posteriorly compressed morphologies with marked differences in cell shape and plate arrangement. Here we report a third globular, epiphytic and tychoplanktonic species from the coasts of Ubatuba, Brazil. The new species can be distinguished from G. yasumotoi and G. ruetzleri by its broader first apical plate that occupies a larger portion of the epitheca. Accordingly, phylogenetic trees from small subunit (SSU and large subunit (LSU ribosomal DNA sequences also showed strongly supported separation of the new species from the G. yasumotoi/G. ruetzleri group albeit with short distance. The molecular phylogenies, which included new sequences of the planktonic species Goniodoma polyedricum, further indicated that the globular species of Gambierdiscus formed a tight clade, clearly separated (with strong bootstrap support from the clade of lenticular species including the type for Gambierdiscus. The morphological and molecular data in concert support the split of Gambierdiscus sensu lato into two genera. Gambierdiscus sensu stricto should be reserved for the species with lenticular shapes, highly compressed anterioposteriorly, with short-shank fishhook apical pore plate, large 2' plate, low and ascending cingular displacement, and pouch-like sulcal morphology. The new genus name Fukuyoa gen. nov. should be applied to the globular species, slightly laterally compressed, with long-shank fishhook apical pore plate, large 1' plate, greater and descending cingular displacement, and not pouch-like vertically-oriented sulcal morphology. Fukuyoa contains the new species Fukuyoa paulensis gen. et sp. nov., and F. yasumotoi comb. nov. and F. ruetzleri comb. nov.

The globular cluster systems of 54 Coma ultra-diffuse galaxies: statistical constraints from HST data

Science.gov (United States)

Amorisco, N. C.; Monachesi, A.; Agnello, A.; White, S. D. M.

2018-04-01

We use data from the HST Coma Cluster Treasury program to assess the richness of the globular cluster systems (GCSs) of 54 Coma ultra-diffuse galaxies (UDGs), 18 of which have a half-light radius exceeding 1.5 kpc. We use a hierarchical Bayesian method tested on a large number of mock data sets to account consistently for the high and spatially varying background counts in Coma. These include both background galaxies and intra-cluster globular clusters (ICGCs), which are disentangled from the population of member globular clusters (GCs) in a probabilistic fashion. We find no candidate for a GCS as rich as that of the Milky Way, our sample has GCSs typical of dwarf galaxies. For the standard relation between GCS richness and halo mass, 33 galaxies have a virial mass Mvir ≤ 1011 M⊙ at 90 per cent probability. Only three have Mvir > 1011 M⊙ with the same confidence. The mean colour and spread in colour of the UDG GCs are indistinguishable from those of the abundant population of ICGCs. The majority of UDGs in our sample are consistent with the relation between stellar mass and GC richness of `normal' dwarf galaxies. Nine systems, however, display GCSs that are richer by a factor of 3 or more (at 90 per cent probability). Six of these have sizes ≲1.4 kpc. Our results imply that the physical mechanisms responsible for the extended size of the UDGs and for the enhanced GC richness of some cluster dwarfs are at most weakly correlated.

Tratamento de águas contaminadas por diesel/biodiesel utilizando processo Fenton Treatment of water contaminated by diesel/biodiesel using Fenton process

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Teofani Koslides Mitre

2012-06-01

Full Text Available A contaminação de águas por misturas diesel/biodiesel pode causar grandes impactos ambientais, relacionados à presença de compostos orgânicos recalcitrantes e tóxicos, inviabilizando o uso de processos biológicos de tratamento. A avaliação da biodegradabilidade, nas proporções B0, B25, B50, B75 e B100 (os números especificam o percentual em massa de biodiesel na mistura, indicou que a adição de biodiesel em teores acima de 50% aumenta a biodegradabilidade, alcançando 60 e 80% para B50 e B75, respectivamente. Na aplicação do processo Fenton, a remoção da matéria orgânica foi superior a 80% em todas as misturas, exceto para B0, que apresentou remoção máxima de 50%. A oxidação por Fenton se ajustou a um modelo cinético de pseudo-segunda ordem em relação à concentração de matéria orgânica, e resultou em aumento da biodegradabilidade de até 150%.Waters contaminated with diesel/biodiesel and their blends can cause major environmental impacts, due to the presence of toxic and recalcitrant organic compounds, which invalidate the use of biological treatment processes. Evaluation of biodegradability of the blends B0, B25, B50, B75 and B100 (the numbers specify the mass percentage of biodiesel in the blend indicated that the addition of biodiesel at concentrations above 50% increased biodegradation, reaching 60 and 80% for B50 and B75, respectively. When the Fenton process was used, removal of organic matter was greater than 80 % in all blends, except for B0, which showed maximum removal of 60%. Oxidation by Fenton was fitted with a pseudo-second order kinetic model in relation to the concentration of organic matter and resulted in increased biodegradation of up to 150%.

MORE REMOTE GLOBULAR CLUSTERS IN THE OUTER HALO OF M31

International Nuclear Information System (INIS)

Di Tullio Zinn, Graziella; Zinn, Robert

2013-01-01

We searched the Sloan Digital Sky Survey for outer halo globular clusters (GCs) around M31. Our search of non-stellar objects, within the limits of 0.3 ≤ (g – i) 0 ≤ 1.5 and 14.0 ≤ r 0 ≤ 19.0 concentrated in some remote areas of the extended halo, to a maximum projected distance of 240 kpc, for a total of approximately 200 deg 2 . Another ∼50 deg 2 , ∼5-75 kpc from M31, were surveyed as test areas. In these areas, we identified 39 GCs and 2 GC candidates, 84% of the previously known GCs (93% of the 'classical GCs' and 40% of the 'halo extended clusters', on the cluster classification scheme of Huxor et al.). For the entire survey, we visually inspected 78,516 objects for morphological evidence of cluster status, and we identified 18 new clusters, and 75 candidate clusters. The new clusters include 15 classical globulars and 3 clusters of lower density. Six of the clusters reside in the remote areas of the outer halo, beyond projected distances of 100 kpc. Previously, only MGC1 was found beyond this limit at 117 kpc. The farthest cluster discovered in this survey lies at a projected radius of 158 kpc from M31, assuming that the M31 distance is 780 kpc.

Constraints on H(0) from globular clusters

International Nuclear Information System (INIS)

Vandenberg, D.A.

1988-01-01

On the basis of canonical stellar evolutionary computations, the maximum age of the globular clusters is suggested to be near either 14 Gyr or 18 Gyr, depending on how (O/Fe) varies with (Fe/H) in the cluster stars. The lower estimate requires that H(0) = 65 km/s/Mpc or less, for all Omega(0) = O or greater, if the standard Big-Bang cosmological theory is correct - while the higher age value similarly constrains the Hubble constant to be smaller than 46 km/s/Mpc. Some reduction in the upper limit to cluster ages and a consequent increase in H(0) may be expected if helium diffusion is important in Population II stars; nevertheless, values of H(0) greater than 75 km/s/Mpc still appear to be precluded unless the cosmological constant is nonzero. 51 refs

On the blind use of statistical tools in the analysis of globular cluster stars

Science.gov (United States)

D'Antona, Francesca; Caloi, Vittoria; Tailo, Marco

2018-04-01

As with most data analysis methods, the Bayesian method must be handled with care. We show that its application to determine stellar evolution parameters within globular clusters can lead to paradoxical results if used without the necessary precautions. This is a cautionary tale on the use of statistical tools for big data analysis.

Curve-of-growth analysis of a red giant in the globular cluster M13

International Nuclear Information System (INIS)

Griffin, R.

1979-01-01

A coude spectrogram of a red giant (L973) in the globular cluster M13 is analysed, with respect to α Boo, by the differential curve-of-growth technique. The overall metal abundance is found to be approximately one-tenth of that of α Boo, or one-fortieth that of the Sun. (author)

Blue straggler stars in the globular cluster NGC 5053

International Nuclear Information System (INIS)

Nemec, J.M.; Cohen, J.G.

1989-01-01

A study of the low central concentration globular cluster NGC 5053 based on photometry to 23 mag is reported. Deep C-M diagrams are presented, a mean metal abundance for the cluster is derived from the color of the RGB at the level of the horizontal branch, and theoretical isochrones are used to derive a distance modulus of (m - M0) = 16.05 + or - 0.14 mag and an age of 18 + or - 3 Gyr. A luminosity function based on subgiant and upper main-sequence stars is also constructed. A total of 24 blue stragglers in NGC 5053 are identified and their properties are studied. 65 references

Neutron star/red giant encounters in globular clusters

International Nuclear Information System (INIS)

Bailyn, C.D.

1988-01-01

The author presents a simple expression for the amount by which xsub(crit) is diminished as a star evolves xsub(crit) Rsub(crit)/R*, where Rsub(crit) is the maximum distance of closest approach between two stars for which the tidal energy is sufficient to bind the system, and R* is the radius of the star on which tides are being raised. Also it is concluded that tidal capture of giants by neutron stars resulting in binary systems is unlikely in globular clusters. However, collisions between neutron stars and red giants, or an alternative process involving tidal capture of a main-sequence star into an initially detached binary system, may result either in rapidly rotating neutron stars or in white dwarf/neutron star binaries. (author)

Dynamics of globular molecules: moisture effect on the Rayleigh scattering spectrum of the Moessbauer radiation

International Nuclear Information System (INIS)

Chesskaya, T.Yu.

1998-01-01

The Rayleigh scattering spectrum of the Moessbauer radiation is plotted on the model simulating globular macromolecules. The modeling results are compared with experimental data on the spectra of the Rayleigh scattering of the Moessbauer radiation for various moisture content and hydratation dependence of the elastic scattering portion

NEAR-IR PHOTOMETRIC PROPERTIES OF HB, MSTO, AND SGB FOR METAL POOR GALACTIC GLOBULAR CLUSTERS

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J.-W. Kim

2007-03-01

Full Text Available We report photometric features of the HB, MSTO, and SGB for a set of metal-poor Galactic globular clusters on the near-IR CMDs. The magnitude and color of the MSTO and SGB are measured on the fiducial normal points of the CMDs by applying a polynomial fit. The near-IR luminosity functions of horizontal branch stars in the classical second parameter pair M3 and M13 indicate that HB stars in M13 are dominated by hot stars that are rotatively faint in the infrared, whereas HB stars in M3 are brighter than those in M13. The luminosity functions of HB stars in the observed bulge clusters, except for NGC 6717, show a trend that the fainter hot HB stars are dominated in the relatively metal-poor clusters while the relatively metal-rich clusters contain the brighter HB stars. It is suggestive that NGC 6717 would be an extreme example of the second-parameter phenomenon for the bulge globular clusters.

The Hot Stellar Content and HB morphology of the massive globular cluster G1

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Rich, R.

2010-09-01

We propose to obtain deep WFC3 imagery of the Local Group's most luminous globular cluster, G1. Our primary aim is to define the hot stellar content and the extent of what appears to be a multimodal horizontal branch, analogous to those known in Omega Cen and NGC 2808. G1 is 40 kpc distant in the M31, and it would have been highly unlikely that collision with a giant molecular clould would be responsible for the complex populations which must therefore be the result of self-enrichment. We will obtain data very similar to those obtained for the known Galactic multimodal globular clusters NGC 6388 and 6441, and compare the stellar distribution on the horizontal branch with models. We can constrain the fraction of helium-enriched stars, if present, and search for supra-horizontal branch and other anomalous hot, evolved, stars. Parallel ACS observations will be the deepest ever obtained in the adjacnt field to G1, and will help to constrain whether G1 was the nucleus of a now disrupted galaxy.

The small angle x-ray scattering of globular proteins in solution during heat denaturation

Science.gov (United States)

Banuelos, Jose; Urquidi, Jacob

2008-10-01

The ability of proteins to change their conformation in response to changes in their environment has consequences in biological processes like metabolism, chemical regulation in cells, and is believed to play a role in the onset of several neurodegenerative diseases. Factors such as a change in temperature, pressure, and the introduction of ions into the aqueous environment of a protein can give rise to the folding/unfolding of a protein. As a protein unfolds, the ratio of nonpolar to polar groups exposed to water changes, affecting a protein's thermodynamic properties. Using small angle x-ray scattering (SAXS), we are currently studying the intermediate protein conformations that arise during the folding/unfolding process as a function of temperature for five globular proteins. Trends in the observed intermediate structures of these globular proteins, along with correlations with data on protein thermodynamics may help elucidate shared characteristics between all proteins in the folding/unfolding process. Experimental design considerations will be discussed and preliminary results for some of these systems will be presented.

Processing and characterization of an extruded snack made from broken rice flour and broken common bean flour

OpenAIRE

CARVALHO, Ana Vânia; BASSINELLO, Priscila Zaczuk; MATTIETTO, Rafaella de Andrade; CARVALHO, Rosângela Nunes; RIOS, Alessandro de Oliveira; SECCADIO, Lara Lima

2012-01-01

Este trabalho teve por objetivo desenvolver nova formulação de snack por extrusão termoplástica a partir de mistura de farinhas de quirera de arroz e de bandinha de feijão, bem como avaliar o potencial nutricional, tecnológico e sensorial do novo produto. A farinha de bandinha de feijão carioca foi incorporada à farinha de quirera de arroz na proporção de 30%. O snack foi produzido em extrusora monorrosca, escala piloto. Os parâmetros de extrusão foram fixos, utilizando-se três zonas de extru...

Diseño e implementación de un sitio web utilizando Drupal 7

OpenAIRE

PONS TUR, MARÍA JOSÉ

2012-01-01

En el presente proyecto se mostrará el diseño e implementación de un sitio web utilizando Drupal 7. El proyecto será una página web de un gimnasio llamado Nova Forme, con la finalidad de tener al alcance toda la información de todos los servicios de belleza ofrecidos por el gimnasio, informaciones de todas las actividades y horarios impartidas en el gimnasio, e información de las entradas del hammam entre otras. Pons Tur, MJ. (2012). Diseño e implementación de un sitio web utilizando Drupa...

Efeito da compatibilização da mistura NBR/EVA sobre sua morfologia de fase co-contínua Effect of the compatibilization of NBR/EVA blends on co-continuous morphology

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Bluma G. Soares

2003-01-01

Full Text Available O objetivo deste trabalho foi investigar a influência do poli (etileno-co-acetato de vinila funcionalizado com grupos mercaptana (EVALSH nas propriedades reológicas, morfológicas e dinamico-mecânicas de misturas envolvendo borracha nitrílica (NBR e copolímero de etileno - acetato de vinila (EVA. Experiências envolvendo extração seletiva da fase NBR associadas à análise de microscopia eletrônica de varredura indicaram que estruturas do tipo co-contínuas são formadas em uma faixa de composição de 30 a 60 % em massa de EVA. A adição de EVALSH não afetou esta faixa de co-continuidade, porém deslocou o limiar de percolação para menores teores de EVA. Este comportamento foi mais pronunciado em misturas ricas em NBR. A faixa de co-continuidade também foi evidenciada a partir de análise dinamico-mecânica. Dados reológicos revelaram também que a adição de EVALSH aumentou a viscosidade do sistema para misturas ricas em NBR.The influence of ethylene-vinyl acetate copolymer functionalized with mercapto groups (EVALSH on rheological, morphological and dynamic mechanical properties of nitrilic rubber (NBR/ ethylene - vinyl acetate copolymer (EVA blends has been investigated. Selective extraction experiments of NBR phase and scanning electron micrography suggest that co-continuous morphologies were formed in a range of blend compositions from 30 to 60 wt% of EVA. The addition of EVALSH did not affect the co-continuous range but shifted the percolation threshold of NBR-richer blends towards lower amount of EVA. The co-continuous range was also evidenced by dynamic mechanical analysis. Rheological data also revealed that the presence of EVALSH increased the viscosity of the blends containing higher amounts of NBR.

A Revised Velocity for the Globular Cluster GC-98 in the Ultra Diffuse Galaxy NGC 1052-DF2

Science.gov (United States)

van Dokkum, Pieter; Cohen, Yotam; Danieli, Shany; Romanowsky, Aaron; Abraham, Roberto; Brodie, Jean; Conroy, Charlie; Kruijssen, J. M. Diederik; Lokhorst, Deborah; Merritt, Allison; Mowla, Lamiya; Zhang, Jielai

2018-06-01

We recently published velocity measurements of luminous globular clusters in the galaxy NGC1052-DF2, concluding that it lies far off the canonical stellar mass - halo mass relation. Here we present a revised velocity for one of the globular clusters, GC-98, and a revised velocity dispersion measurement for the galaxy. We find that the intrinsic dispersion $\\sigma=5.6^{+5.2}_{-3.8}$ km/s using Approximate Bayesian Computation, or $\\sigma=7.8^{+5.2}_{-2.2}$ km/s using the likelihood. The expected dispersion from the stars alone is ~7 km/s. Responding to a request from the Editors of ApJ Letters and RNAAS, we also briefly comment on the recent analysis of our measurements by Martin et al. (2018).

CONSTRAINTS ON HELIUM ENHANCEMENT IN THE GLOBULAR CLUSTER M3 (NGC 5272): THE HORIZONTAL BRANCH TEST

International Nuclear Information System (INIS)

Catelan, M.; Valcarce, A. A. R.; Cortes, C.; Grundahl, F.; Sweigart, A. V.

2009-01-01

It has recently been suggested that the presence of multiple populations showing various amounts of helium enhancement is the rule, rather than the exception, among globular star clusters. An important prediction of this helium enhancement scenario is that the helium-enhanced blue horizontal branch (HB) stars should be brighter than the red HB stars which are not helium enhanced. In this Letter, we test this prediction in the case of the Galactic globular cluster M3 (NGC 5272), for which the helium-enhancement scenario predicts helium enhancements of ∼>0.02 in virtually all blue HB stars. Using high-precision Stroemgren photometry and spectroscopic gravities for blue HB stars, we find that any helium enhancement among most of the cluster's blue HB stars is very likely less than 0.01, thus ruling out the much higher helium enhancements that have been proposed in the literature.

The globular cluster ω Centauri and its RR Lyrae variables

International Nuclear Information System (INIS)

Dickens, R.J.

1989-07-01

The significance of some of the unusual characteristics of the globular cluster ωCentauri in various fundamental problems is explored. Interest is centred on the properties of the cluster RR Lyraes, and what they can contribute to studies of early cluster chemical enrichment, stellar pulsation, the distance scale, stellar evolution, stellar ages and the Oosterhoff period-shift problem. This article, which is intended to highlight problems and progress rather than give a comprehensive review, includes new results based on photometry of the RR Lyraes, red giants, subgiants, horizontal-branch and main sequence stars in the cluster. (author)

UTILIZAÇÃO DE MISTURAS DE CAVACOS INDUSTRIAIS COM RESÍDUOS DE SERRARIA PROVENIENTES DE MADEIRAS DE Eucalyptus grandis DE DIFERENTES IDADES PARA PRODUÇÃO DE PASTA KRAFT

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Angelina Maron

2004-01-01

Full Text Available Este trabalho estuda a viabilidade técnica do uso conjunto de resíduos de serraria (costaneiras dentre outros e topos de árvores de Eucalyptus grandis com 15 anos de idade, destinadas à produção de madeira sólida, com madeira de árvores de plantio industrial, com 7 anos de idade, destinadas à produção de pasta kraft. São apresentados modelos úteis à realização de estimativas de alturas total e comercial e de volumes de madeira comercial e adequadas para serraria, todos baseados no DAP. São fornecidos dados anatômicos, de densidade básica e de composição química de misturas desses tipos de materiais. Mostra-se que é tecnicamente viável realizar deslignificações kraft com misturas contendo madeira comercial de Eucalyptus grandis 7 anos com resíduo de serraria ou topos de árvores. A deslignificação kraft de resíduos de serraria resulta em perda rápida de rendimento, mas a pasta produzida sob as mesmas condições apresenta número Kappa menor que a de Eucalyptus grandis com 7 anos. A deslignificação de topos de árvores resulta em perda de rendimento bruto, mas o consumo específico de madeira é menor. Conforme aumenta a madeira de topo nas misturas, ocorre um aumento na densidade básica, o comprimento médio das fibras fica praticamente o mesmo e um pequeno aumento no teor de lignina; há diminuição nos extrativos em etanol, em água quente e na solubilidade em NaOH 1%. Diminui um pouco o rendimento bruto em pasta, mas praticamente não afeta o número Kappa, caindo sensivelmente o consumo específico de madeira. Com o aumento de madeira de resíduo de serraria das árvores nas misturas, praticamente não há efeito sobre a densidade básica, mas o comprimento médio das fibras aumenta, ocorrendo também um pequeno aumento no teor de lignina. Os extrativos em etanol, em água quente e na solubilidade em NaOH 1% diminuem. O rendimento bruto em pasta cai um pouco, mas com uma queda sensível no número Kappa

AVALIAÇÃO EXPERIMENTAL DA SENSIBILIDADE DO BIODIESEL B5 EM FROTAS DE ÔNIBUS URBANO E INTERURBANO UTILIZANDO MOTOR DIESEL

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M. F. Oliveira Filho

2012-06-01

Full Text Available O objetivo deste estudo é investigar a consolidação do uso do biodiesel em motores de duas frotas de ônibus, uma urbana e uma interurbana. Entende-se serem necessários estudos para se observar, do ponto de vista tecnológico, se o uso do biodiesel apresenta problemas quanto ao desgaste das peças diretamente envolvidas com o combustível e também observar as flutuações, para mais ou para menos, do consumo específico desse combustível. O diesel fóssil – tipo D (interior ou marítmo – e Biodiesel B5 foram analisados analiticamente, investigando-se também o teor de enxofre presente. Duas frotas de ônibus urbana e interurbana, sediadas em Natal/RN – Brasil, possuíam 41 e 13 veículos, respectivamente. Foram analisadas as planilhas de cada veículo no período de três anos (2008 a 2010 e entrevistados os responsáveis pela manutenção e condução da frota para observar os relatos dos mesmos quanto aos aspectos resultantes da política brasileira ambientalmente amigável para substituição do óleo diesel pelo B5. Segundo uma avaliação do consumo de combustível, houve um aumento não-linear (cerca de 5 % quando da substituição do diesel pelo biodiesel B5, mas não foi observada qualquer manutenção adicional relacionada com a sua utilização; todavia foi compensado pela redução de emissões de compostos químicos de dióxido de nitrogênio e teor de enxofre, como medido por Fernandes, 2011. Além disso, a funcionalidade ea vida residual em serviço dos ônibus utilizando misturas diesel são discutidos.

Ambientes virtuales de aprendizaje utilizando realidad aumentada

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Diana Nancy Martínez García

2018-03-01

Full Text Available Realidad aumentada o Augmented reality es una nueva tecnología que al combinarla con espacios físicos permite ampliar el espectro de la información relacionada con dichos espacios; esto se hace a través de la superposición de imágenes, información o material audiovisual específico aplicado a cualquier área de conocimiento. Los ambientes virtuales de aprendizaje basados en realidad aumentada prometen innovación debido a que transforman los escenarios de aprendizaje real mediante el uso de nuevas tecnologías aplicadas al ámbito educativo, complementando de esta manera la percepción e interacción con el mundo real; logrando el acceso a nuevos contenidos prescindiendo de recursos físicos. En cuanto al uso de la realidad aumentada aplicada al área de enfermería, existe un sinnúmero de herramientas para complementar una clase magistral y enriquecer el proceso de aprendizaje. Sin embargo, la mayoría de los desarrollos realizados utilizando realidad aumentada proviene de contextos diferentes al nuestro, por lo que resulta importante fomentar el uso de este tipo de herramientas para que suscite el interés de los desarrolladores locales de tecnologías aplicadas al ámbito educativo y más específicamente el de salud. El objetivo de la presente revisión fue fundamentar teóricamente acerca de los ambientes virtuales de aprendizaje utilizando aplicaciones basadas en realidad aumentada.

Ghosts of Milky Way's past: the globular cluster ESO 37-1 (E 3)

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de la Fuente Marcos, R.; de la Fuente Marcos, C.; Moni Bidin, C.; Ortolani, S.; Carraro, G.

2015-09-01

Context. In the Milky Way, most globular clusters are highly conspicuous objects that were found centuries ago. However, a few dozen of them are faint, sparsely populated systems that were identified largely during the second half of the past century. One of the faintest is ESO 37-1 (E 3) and as such it remains poorly studied, with no spectroscopic observations published so far although it was discovered in 1976. Aims: We investigate the globular cluster E 3 in an attempt to better constrain its fundamental parameters. Spectroscopy of stars in the field of E 3 is shown here for the first time. Methods: Deep, precise VI CCD photometry of E 3 down to V ~ 26 mag is presented and analysed. Low-resolution, medium signal-to-noise ratio spectra of nine candidate members are studied to derive radial velocity and metallicity. Proper motions from the UCAC4 catalogue are used to explore the kinematics of the bright members of E 3. Results: Isochrone fitting indicates that E 3 is probably very old, with an age of about 13 Gyr; its distance from the Sun is nearly 10 kpc. It is also somewhat metal rich with [Fe/H] = -0.7. Regarding its kinematics, our tentative estimate for the proper motions is (μα cosδ,μδ) = (-7.0 ± 0.8, 3.5 ± 0.3) mas yr-1 (or a tangential velocity of 382 ± 79 km s-1) and for the radial velocity 45 ± 5 km s-1 in the solar rest frame. Conclusions: E 3 is one of the most intriguing globular clusters in the Galaxy. Having an old age and being metal rich is clearly a peculiar combination, only seen in a handful of objects like the far more conspicuous NGC 104 (47 Tucanae). In addition, its low luminosity and sparse population make it a unique template for the study of the final evolutionary phases in the life of a star cluster. Unfortunately, E 3 is among the most elusive and challenging known globular clusters because field contamination severely hampers spectroscopic studies. This research note is based on observations made with the ESO VLT at the

AGB sodium abundances in the globular cluster 47 Tucanae (NGC 104)

Energy Technology Data Exchange (ETDEWEB)

Johnson, Christian I. [Harvard–Smithsonian Center for Astrophysics, 60 Garden Street, MS-15, Cambridge, MA 02138 (United States); McDonald, Iain; Zijlstra, Albert A., E-mail: cjohnson@cfa.harvard.edu, E-mail: iain.mcdonald-2@manchester.ac.uk, E-mail: albert.zijlstra@manchester.ac.uk [Jodrell Bank Centre for Astrophysics, Alan Turing Building, Manchester M13 9PL (United Kingdom); and others

2015-02-01

A recent analysis comparing the [Na/Fe] distributions of red giant branch (RGB) and asymptotic giant branch (AGB) stars in the Galactic globular cluster NGC 6752 found that the ratio of Na-poor to Na-rich stars changes from 30:70 on the RGB to 100:0 on the AGB. The surprising paucity of Na-rich stars on the AGB in NGC 6752 warrants additional investigations to determine if the failure of a significant fraction of stars to ascend the AGB is an attribute common to all globular clusters. Therefore, we present radial velocities, [Fe/H], and [Na/Fe] abundances for 35 AGB stars in the Galactic globular cluster 47 Tucanae (47 Tuc; NGC 104), and compare the AGB [Na/Fe] distribution with a similar RGB sample published previously. The abundances and velocities were derived from high-resolution spectra obtained with the Michigan/Magellan Fiber System and MSpec spectrograph on the Magellan–Clay 6.5 m telescope. We find the average heliocentric radial velocity and [Fe/H] values to be 〈RV{sub helio.}〉 = −18.56 km s{sup −1} (σ = 10.21 km s{sup −1}) and 〈[Fe/H]〉 = −0.68 (σ = 0.08), respectively, in agreement with previous literature estimates. The average [Na/Fe] abundance is 0.12 dex lower in the 47 Tuc AGB sample compared to the RGB sample, and the ratio of Na-poor to Na-rich stars is 63:37 on the AGB and 45:55 on the RGB. However, in contrast to NGC 6752, the two 47 Tuc populations have nearly identical [Na/Fe] dispersion and interquartile range values. The data presented here suggest that only a small fraction (≲20%) of Na-rich stars in 47 Tuc may fail to ascend the AGB, which is a similar result to that observed in M13. Regardless of the cause for the lower average [Na/Fe] abundance in AGB stars, we find that Na-poor stars and at least some Na-rich stars in 47 Tuc evolve through the early AGB phase. The contrasting behavior of Na-rich stars in 47 Tuc and NGC 6752 suggests that the RGB [Na/Fe] abundance alone is insufficient for predicting if a star will

Diferentes Misturas de Substrato com Lodo de Esgoto Compostado Enriquecido e Substrato Comercial em Quaresmeira

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Thomaz Figueiredo Lobo

2018-04-01

Full Text Available Tibouchina granulosa (Quaresmeira é utilizada em projetos de reflorestamento devido ao seu crescimento rápido. Para garantir melhores resultados, alternativas viáveis como o lodo de esgoto vêm sendo procurada, pois oferece qualidade às mudas, além disso, contribui para o ambiente por ser uma substância reutilizada. Avaliamos aqui os efeitos do substrato com lodo de esgoto. No delineamento experimental foram utilizados 5 tratamentos com diferentes misturas de substratos de lodo de esgoto compostado e comerciais e 4 repetições. A irrigação foi realizada 3 vezes ao dia, por período de 2,5 minutos. Os resultados revelaram que os melhores tratamentos em altura foram 75% LC + 25% SC, 50% LC + 50% SCe 25% LC + 75% BSC para o diâmetro do coleto foram 75% LC + 25% SCe 50% LC + 50% SCe na avaliação nutricional 75% LC + 25% SC. Para a produção de mudas de T. granulosa é recomendado a utilização da combinação de lodo de esgoto e substrato comercial.

Portal WEB 2.0. utilizando Framework Struts

OpenAIRE

Palacín Mateo, Manuel

2007-01-01

El propósito de este proyecto es la implementación de un portal interactivo de contactos utilizando las tecnologías J2EE mediante Struts y siguiendo la tendencia Web 2.0. Previo a esta implementación se ha hecho una valoración del mercado actual de los portales de contactos y se han evaluado los servicios que ofrecen para posteriormente añadirlos a la demostración tecnológica. Tras esto se ha explicado lo que es la tendencia Web 2.0. Finalmente se han evaluado las diferentes opciones o tec...

LISA Sources in Milky Way Globular Clusters.

Science.gov (United States)

Kremer, Kyle; Chatterjee, Sourav; Breivik, Katelyn; Rodriguez, Carl L; Larson, Shane L; Rasio, Frederic A

2018-05-11

We explore the formation of double-compact-object binaries in Milky Way (MW) globular clusters (GCs) that may be detectable by the Laser Interferometer Space Antenna (LISA). We use a set of 137 fully evolved GC models that, overall, effectively match the properties of the observed GCs in the MW. We estimate that, in total, the MW GCs contain ∼21 sources that will be detectable by LISA. These detectable sources contain all combinations of black hole (BH), neutron star, and white dwarf components. We predict ∼7 of these sources will be BH-BH binaries. Furthermore, we show that some of these BH-BH binaries can have signal-to-noise ratios large enough to be detectable at the distance of the Andromeda galaxy or even the Virgo cluster.

Globular conformation of some ribosomal proteins in solution

International Nuclear Information System (INIS)

Serdyuk, I.N.; Spirin, A.S.

1978-01-01

The possibility that such RNA-binding proteins of the 30 S subparticle as S4, S7, S8 and S16 exist in the form of compact globules in solution has been explored experimentally. These proteins have been studied in D 2 O solution by neutron scattering to measure their radii of gyration. This type of radiation using D 2 O as a solvent provides the maximum 'contrast', that is the maximum difference between the scattering of the protein and the solvent. It allowed measurements to be made using protein at <= 1.5 mg/ml. The radii of gyration for the ribosomal proteins S4, S7, S8 and S16 were found to be relatively small corresponding to the radii of gyration of compact globular proteins of the same molecular weights. (Auth.)

BVRI CCD photometry of the metal-poor globular cluster M68 (NGC 4590)

International Nuclear Information System (INIS)

Alcaino, G.; Liller, W.; Alvarado, F.; Wenderoth, E.

1990-01-01

BVRI photometry of the low metallicity globular cluster M68 (NGC 4590) was obtained with a CCD camera and the 2.2-m ESO telescope. The resulting BV color-magnitude diagrams are compared with the observations of McClure et al. (1987). The observations are also compared with theoretical isochrones, yielding a cluster age of 13 Gyr with a likely external uncertainty of 2 or 3 Gyr. 25 refs

Distribución en gran escala de los cúmulos globulares en Fornax

Science.gov (United States)

Ostrov, P. G.

Para analizar los cúmulos globulares azules y rojos de NGC 1399 asociados con NGC 1399 en particular, o si los cúmulos azules representaban un sistema asociado con el cúmulo de Fornax en general, se obtuvieron imágenes CCD de gran formato con el telescopio de 4m del CTIO, en las bandas C y T1. Se describe el método empleado y lo encontrado.

New Target for an Old Method: Hubble Measures Globular Cluster Parallax

Science.gov (United States)

Hensley, Kerry

2018-05-01

Measuring precise distances to faraway objects has long been a challenge in astrophysics. Now, one of the earliest techniques used to measure the distance to astrophysical objects has been applied to a metal-poor globular cluster for the first time.A Classic TechniqueAn artists impression of the European Space Agencys Gaia spacecraft. Gaia is on track to map the positions and motions of a billion stars. [ESA]Distances to nearby stars are often measured using the parallax technique tracing the tiny apparent motion of a target star against the background of more distant stars as Earth orbits the Sun. This technique has come a long way since it was first used in the 1800s to measure the distance to stars a few tens of light-years away; with the advent of space observatories like Hipparcos and Gaia, parallax can now be used to map the positions of stars out to thousands of light-years.Precise distance measurements arent only important for setting the scale of the universe, however; they can also help us better understand stellar evolution over the course of cosmic history. Stellar evolution models are often anchored to a reference star cluster, the properties of which must be known precisely. These precise properties can be readily determined for young, nearby open clusters using parallax measurements. But stellar evolution models that anchor on themore-distant, ancient, metal-poor globular clusters have been hampered by theless-precise indirect methods used tomeasure distance to these faraway clusters until now.Top: An image of NGC 6397 overlaid with the area scanned by Hubble (dashed green) and the footprint of the camera (solid green). The blue ellipse represents the parallax motion of a star in the cluster, exaggerated by a factor of ten thousand. Bottom: An example scan from this field. [Adapted from Brown et al. 2018]New Measurement to an Old ClusterThomas Brown (Space Telescope Science Institute) and collaborators used the Hubble Space Telescope todetermine the

GeraÃÃo de biogÃs utilizando cama de aviÃrio e manipueira

OpenAIRE

Ana Beatryz Prenzier Suzuki

2012-01-01

A procura por energia tÃm se mostrado cada vez maior e para suprir essa demanda à necessÃrio buscar fontes alternativas de energia. O presente trabalho teve como objetivo verificar a produÃÃo de biogÃs atravÃs da mistura da cama de aviÃrio com manipuiera para obtenÃÃo de biogÃs e analisando seus efluentes e verificando a reduÃÃo de carga orgÃnica. Tentando assim resolver a questÃo ambiental da destinaÃÃo dos mesmos e produzindo energia limpa e renovÃvel contribuindo para a matr...

Levels of mineral mixture and urea in supplementation of crossbred heifers, with Gyr predominance, reared at pasture during the dry season Níveis de mistura mineral e ureia na suplementação de dietas para novilhas mestiças, com predominância de Gir, recriadas a pasto durante o período da seca

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Bruno Pietsch Cunha Mendonça

2010-10-01

Full Text Available It was evaluated several levels of mineral mixture and urea for crossbred heifers, with Gyr predominance, in the dry season period in Zona da Mata region in Minas Gerais. The experiment was carried out in a Brachiaria decumbens pasture area, divided in five paddocks of 3.5 hectares. It was used 35 heifers distributed in a 2 õ 2 + 1 factorial scheme, composed of two levels of urea (10 and 25%, two levels of mineral salt (10 and 25% and a control diet (only mineral salt, totaling five diets, each one evaluated with seven replicates. The supplements were based on ground corn, urea, ammonia sulfate and mineral mixture with 32 to 72% crude protein, and they composed the following diets: MM ( mineral mix, 10:10 (10% mineral mix, 10% urea and 80% corn; 10:25 (10% mineral mix, 25% urea and 65% corn; 25:10 (25% mineral mix, 10% urea and 65% corn, and 25:25 (25% mineral mix, 25% urea and 50% corn. Urea and mineral salt are effective in controlling supplement intake by bovines growing on pastures during dry season because the higher their levels, the lower the intake of supplements. Diets with 25% urea and 10% mineral salt provided higher daily weight gain and higher weight gain:supplemment intake ratio.Avaliaram-se diversos níveis de mistura mineral e ureia para novilhas mestiças, com predominância de Gir, no período da seca na região da Zona da Mata de Minas Gerais. O experimento foi realizado em uma área de pastagem formada de Brachiaria decumbens, dividida em cinco piquetes de 3,5 ha. Utilizaram-se 35 novilhas distribuídas em um esquema fatorial tipo 2 õ 2 + 1, composto de dois níveis de ureia (10 e 25%, dois níveis de sal mineral (10 e 25% e uma dieta controle (somente sal mineral, totalizando cinco dietas, cada uma avaliada com sete repetições. Os suplementos foram à base de milho moído, ureia, sulfato de amônia e mistura mineral, com 32 a 72% de proteína bruta, e compuseram as seguintes dietas: MM (mistura mineral; 10:10 (10% de

Modeling and Analysis of a Spectrum of the Globular Cluster NGC 2419

OpenAIRE

Sharina, M. E.; Shimansky, V. V.; Davoust, E.

2012-01-01

NGC 2419 is the most distant massive globular cluster in the outer Galactic halo. It is unusual also due to the chemical peculiarities found in its red giant stars in recent years. We study the stellar population of this unusual object using spectra obtained at the 1.93-m telescope of the Haute-Provence Observatory. At variance with commonly used methods of high-resolution spectroscopy applicable only to bright stars, we employ spectroscopic information on the integrated light of the cluster....

HERRAMIENTAS GEOMÉTRICAS PARA EL DISEÑO BÁSICO DE COLUMNAS DE DESTILACIÓN CON MEZCLAS AZEOTRÓPICAS HETEROGÉNEAS TERNARIAS: I. CÁLCULO DEL REFLUJO MÍNIMO FERRAMENTAS GEOMÉTRICAS PARA O DESENHO BÁSICO DE COLUNAS DE DESTILACÃO COM MISTURAS AZEOTRÓPICAS HETEROGÊNEAS TERNARIAS: I. CÁLCULO DO REFLUXO MÍNIMO GEOMETRICAL TOOLS FOR THE BASIC DESIGN OF DISTILLATION COLUMNS WITH TERNARY HETEROGENEOUS AZEOTROPIC MIXTURES: I. MINIMUM REFLUX CALCULATION

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César Augusto Sánchez

2012-12-01

Full Text Available En este trabajo se presentan herramientas numéricas útiles para calcular el reflujo mínimo en torres infinitas. Como eje de los argumentos se consideran dos elementos geométricos: los ramales de puntos pinch (RPP y la estructura determinada por la binodal y la línea de vapor. El interés principal consiste en la integración de estos elementos con las fronteras de destilación a reflujo total, con el fin de explorar el problema del diseño conceptual. Se demuestra la utilidad de estos elementos resolviendo el problema del reflujo mínimo (PRM para tres ejemplos que involucran las deshidrataciones de mezclas acuosas de ácido acético utilizando n-amilacetato y de etanol utilizando benceno. Se evidencia que la estructura de las líneas de destilación a reflujo mínimo para las separaciones agudas satisface las regularidades observadas en los sistemas homogéneos.Neste trabalho apresentam-se ferramentas numéricas úteis para calcular o refluxo mínimo em torres infinitas. Como eixo dos argumentos se consideram dois elementos geométricos: os ramais de pontos pinch (RPP e a estrutura determinada pela binodal e a linha de vapor. O interesse principal consiste na integração destes elementos com as fronteiras de destilação a refluxo total com o fim de explorar o problema do desenho conceitual. Demonstra-se a utilidade destes elementos resolvendo o problema do refluxo mínimo (PRM para três exemplos que envolvem as desidratações de misturas aquosas de ácido acético utilizando n-amilacetato e de etanol utilizando benzeno. Evidencia-se que a estrutura das linhas de destilação a refluxo mínimo para as separações agudas satisfaz as regularidades observadas nos sistemas homogêneos.Useful numerical tools to calculate the minimum reflux for infinite towers with heterogeneous azeotropic ternary mixtures are presented. For this, two geometrical elements are involved: the pinch point branches (PPB and the structure defined by the binodal

The gravitational waveforms of white dwarf collisions in globular clusters

International Nuclear Information System (INIS)

Loren-Aguilar, P; Garcia-Berro, E; Lobo, J A; Isern, J

2009-01-01

In the dense central regions of globular clusters close encounters of two white dwarfs are relatively frequent. The estimated frequency is one or more strong encounters per star in the lifetime of the cluster. Such encounters should be then potential sources of gravitational wave radiation. Thus, it is foreseeable that these collisions could be either individually detected by LISA or they could contribute significantly to the background noise of the detector. We compute the pattern of gravitational wave emission from these encounters for a sufficiently broad range of system parameters, namely the masses, the relative velocities and the distances of the two white dwarfs involved in the encounter.

Efeito do processamento em misturas de alumina/ligantes orgânicos usadas na moldagem por injeção em baixa pressão Effect of processing variables in alumina/organic binders mixtures used in low-pressure injection molding

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P . A. Ourique

2013-03-01

Full Text Available A moldagem por injeção em baixa pressão (MIBP é uma técnica que já vem sendo empregada na produção de peças cerâmicas com formas e geometrias complexas. A homogeneidade da mistura de ligantes orgânicos e pós cerâmicos é um fator determinante que deve ser controlado para minimizar a formação de imperfeições no processamento de feedstocks para MIBP. Defeitos típicos de processamento por MIBP, como bolhas de ar e aglomerados, geram gradientes de densidade nas misturas que, após conformação, possuem poucas possibilidades de remoção. Essas imperfeições comprometem o desempenho dos produtos obtidos por essa técnica. Este trabalho está focado na avaliação dessas heterogeneidades e como elas podem ser correlacionadas com a variação da densidade aparente e com o comportamento reológico dessas misturas. Para tanto, aluminas submicrométricas, como recebida e desaglomerada, foram adicionadas a uma mistura fundida de ligantes a base de parafinas, ceras e aditivos e processada em dois tipos diferentes de misturadores, com e sem o auxílio de vácuo. Foi observada a presença de aglomerados existentes na alumina como recebida, possivelmente gerados durante a etapa de calcinação. Também foi observado que o tipo de misturador e a aplicação ou não de vácuo durante a etapa final do processamento têm grande influência no tempo de mistura necessário para reduzir a viscosidade do feedstock para a injeção.The low-pressure injection molding (LPIM is a technique already being used in the production of ceramic parts with complex shapes and geometries. The homogeneity of the mixture of organic binder and ceramic powder is a determining factor which must be controlled to minimize defects formation while feedstock processing to LPIM. Typical defects of LPIM processing, such as air bubbles and agglomerates, generate density gradients in the mixtures, which, after shaping, have little possibility of removal. These imperfections

The pulsation mode and period-luminosity relationship of cool variables in globular clusters

International Nuclear Information System (INIS)

Whitelock, P.A.

1986-01-01

The period-luminosity-temperature relationship for globular cluster red and yellow variables is examined. The results suggest that the higher temperature, more metal-deficient cluster variables pulsate in the fundamental mode, while the lower temperature more metal-rich variables pulsate in the first overtone. On the assumption that this is correct, a relationship between fundamental period and bolometric magnitude is derived for cluster variables with observed periods of between 1 and 300 days. (author)

Tensão superficial estática de misturas em tanque de glyphosate + chlorimuron-ethyl isoladas ou associadas com adjuvantes Static superficial tension of glyphosate and chlorimuron-ethyl tank mixtures with or without adjuvants

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C.D.G. Maciel

2010-01-01

Full Text Available Objetivou-se neste estudo avaliar a tensão superficial estática, o pH e a produção da espuma de misturas em tanque de glyphosate + chlorimuron-ethyl, associadas ou não com adjuvantes. Dois trabalhos foram realizados, sendo a primeira etapa desenvolvida em delineamento inteiramente casualizado com seis tratamentos e 20 repetições, representados por soluções dos herbicidas glyphosate (540,0 g e.a. ha-1 e chlorimuron-ethyl (7,5 g ha-1, isolados e em mistura em tanque nas formulações: Polaris®; Roundup Ready®; Classic®; Polaris® + Classic®; Roundup Ready® + Classic® e testemunha (água. Na segunda etapa foram estudados em DIC 70 tratamentos e 20 repetições, em fatorial 2 x 5 x 7, constituído por duas misturas de glyphosate com chlorimuron-ethyl (Polaris® + Classic® e Roundup Ready ® + Classic®, cinco adjuvantes (Joint Oil®; Nimbus®; Assist®; Natur' Oil® e Agr' Óleo® e sete doses dos adjuvantes (0,000; 0,031; 0,062; 0,125; 0,250; 0,500 e 1,000% de v/v. As soluções de Polaris® e Roundup Ready®; isoladas ou em misturas com Classic®; caracterizaram-se por tensões superficiais estáticas de 43,2 e 35,9 mN m-1 e pH médios em torno de 4,5 a 4,6, respectivamente. As misturas de Polaris®+Classic®; Roundup Ready®+Classic® e Classic® apresentaram a maior quantidade e persistência da espuma ao longo do tempo, quando comparadas às formulações de Polaris® e Roundup Ready®. Os adjuvantes promoveram redução da tensão superficial quando associados às misturas de Polaris® + Classic® e Roundup Ready® + Classic®; caracterizando-se em termos de eficiência pela ordem decrescente: Nimbus® (36,5% e 25,8% This work aimed to evaluate static superficial tension, pH and foam production in glyphosate + chlorimuron-ethyl tank mixtures with or without adjuvants. The experiment consisted of two stages, with the first stage being arranged in a complete randomized design, with six treatments and 20 replications, represented

Utilização de NBR modificada com grupos 2-oxazolina em misturas de NBR/EVA Utilization of 2-oxazoline modified NBR in NBR/EVA blends

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Mauricio S. M. Almeida

2003-06-01

Full Text Available Misturas envolvendo borracha nitrílica e copolímeros de etileno-acetato de vinila na proporção 70:30 % em peso, foram preparadas na presença de borracha nitrílica funcionalizada com 2-oxazolina isoladamente ou combinada com EVA funcionalizado com grupos hidroxila, carboxila ou mercaptana. A reação entre os grupos funcionais foi verificada por análise de FTIR da fração insolúvel de amostras não vulcanizadas e pelo decréscimo nos valores de tan delta nos ensaios dinâmico-mecânicos. A utilização desses copolímeros funcionalizados não influenciou significativamente as propriedades mecânicas, provavelmente devido à proporção da mistura utilizada (rica em NBR o que facilita a localização da NBR funcionalizada no interior da fase elastomérica.Nitrile rubber/ethylene-vinyl acetate copolymer (NBR/EVA blends with ratio of 70/30 wt% were prepared in the presence of functionalized NBR with 2-oxazoline groups. This functionalized copolymer was employed alone or in combination with EVA copolymer functionalized with hydroxyl, carboxyl or mercaptan groups. The reaction between the functional groups was confirmed by FTIR analysis of the unvulcanized samples insoluble fraction, and by the decrease in the tan delta values. The mechanical properties were not substantially affected by the presence of these functionalized copolymers, probably due to the proportion of blend composition (with high amount of NBR, thus forcing the location of functionalized NBR inside the elastomer phase.

Transiently disordered tails accelerate folding of globular proteins.

Science.gov (United States)

Mallik, Saurav; Ray, Tanaya; Kundu, Sudip

2017-07-01

Numerous biological proteins exhibit intrinsic disorder at their termini, which are associated with multifarious functional roles. Here, we show the surprising result that an increased percentage of terminal short transiently disordered regions with enhanced flexibility (TstDREF) is associated with accelerated folding rates of globular proteins. Evolutionary conservation of predicted disorder at TstDREFs and drastic alteration of folding rates upon point-mutations suggest critical regulatory role(s) of TstDREFs in shaping the folding kinetics. TstDREFs are associated with long-range intramolecular interactions and the percentage of native secondary structural elements physically contacted by TstDREFs exhibit another surprising positive correlation with folding kinetics. These results allow us to infer probable molecular mechanisms behind the TstDREF-mediated regulation of folding kinetics that challenge protein biochemists to assess by direct experimental testing. © 2017 Federation of European Biochemical Societies.

Influence of non-thermal plasma on structural and electrical properties of globular and nanostructured conductive polymer polypyrrole in water suspension.

Science.gov (United States)

Galář, Pavel; Khun, Josef; Kopecký, Dušan; Scholtz, Vladimír; Trchová, Miroslava; Fučíková, Anna; Jirešová, Jana; Fišer, Ladislav

2017-11-08

Non-thermal plasma has proved its benefits in medicine, plasma assisted polymerization, food industry and many other fields. Even though, the ability of non-thermal plasma to modify surface properties of various materials is generally known, only limited attention has been given to exploitations of this treatment on conductive polymers. Here, we show study of non-thermal plasma treatment on properties of globular and nanostructured polypyrrole in the distilled water. We observe that plasma presence over the suspension level doesn't change morphology of the polymer (shape), but significantly influences its elemental composition and physical properties. After 60 min of treatment, the relative concentration of chloride counter ions decreased approximately 3 and 4 times for nanostructured and globular form, respectively and concentration of oxygen increased approximately 3 times for both forms. Simultaneously, conductivity decrease (14 times for globular and 2 times for nanostructured one) and changes in zeta potential characteristics of both samples were observed. The modification evolution was dominated by multi-exponential function with time constants having values approximately 1 and 10 min for both samples. It is expected that these time constants are related to two modification processes connected to direct presence of the spark and to long-lived species generated by the plasma.

VLT/UVES spectroscopy of individual stars in three globular clusters in the Fornax dwarf spheroidal galaxy

NARCIS (Netherlands)

Letarte, B; Hill, [No Value; Jablonka, P; Tolstoy, E; Francois, P; Meylan, G

We present a high resolution ( R similar to 43 000) abundance analysis of a total of nine stars in three of the five globular clusters associated with the nearby Fornax dwarf spheroidal galaxy. These three clusters ( 1, 2 and 3) trace the oldest, most metal-poor stellar populations in Fornax. We

Photometric analyses of abundances in dwarf spheroidal galaxies and globular clusters

International Nuclear Information System (INIS)

Light, R.M.

1988-01-01

This study investigated the abundance characteristics of several dwarf spheroidal galaxies. The chemical properties of stars in these galaxies are tracers of the origin and evolution of their stellar populations, and thus can provide constraints on the theories of their formation. To derive this abundance information, photometric observations of stars in a sample of globular clusters, covering a large range in metallicity, were analyzed. Parameters describing the position of the red giant branch were found to correlate very well with cluster metallicity over a large range in abundance. These measurements, made in the Thuan-Gunn photometry system, provide ranking schemes which are, with accurate photometry, more sensitive to changes in metallicity than similar broadband BV parameters. The relations were used to derive an improved estimate of the metallicity of cluster NGC 5053. These metallicity relations were used to analyze the Thuan-Gunn system photometry produced for the Sculptor, Ursa Minor, and Carina galaxies. The excellent agreement between their metallicities and those from other previous studies indicates that globular cluster red giant branch parameters are very useful in ranking dwarf spheroidal populations by metallicity. Together with other galaxian data, strong correlations can be seen between the mean metallicities and dispersions in metallicity and the luminosities of the dwarf spheroidal galaxies. These trends also seem to apply to members of the dwarf elliptical class of galaxies. The ramifications that these correlations and the existence of a metallicity gradient in Sculptor have on the formation of the dwarf spheroidals are discussed

Statistical method for determining ages of globular clusters by fitting isochrones

International Nuclear Information System (INIS)

Flannery, B.P.; Johnson, B.C.

1982-01-01

We describe a statistical procedure to compare models of stellar evolution and atmospheres with color-magnitude diagrams of globular clusters. The isochrone depends on five parameters: m-M, age, [Fe/H], Y, and α, but in practice we can only determine m-M and age for an assumed composition. The technique allows us to determine parameters of the model, their uncertainty, and to assess goodness of fit. We test the method, and evaluate the effect of assumptions on an extensive set of Monte Carlo simulations. We apply the method to extensive observations of NGC 6752 and M5, and to smaller data sets for the clusters M3, M5, M15, and M92. We determine age and m-M for two assumed values of helium Y = (0.2, 0.3), and three values of metallicity with a spread in [Fe/H] of +- 0.3 dex. These result in a spread in age of 5-8 Gyr (1 Gyr = 10 9 yr), and a spread in m-M of 0.5 mag. The mean age is generally younger by 2-3 Gyr than previous estimates. Likely uncertainty associated with an individual fit can be small as 0.4 Gyr. Most importantly, we find that two uncalibratable sources of systematic error make the results suspect. These are uncertainty in the stellar temperatures induced by choice of mixing length, and known errors in stellar atmospheres. These effects could reduce age estimates by an additional 5 Gyr. We conclude that observations do not preclude ages as young as 10 Gyr for globular clusters

Detección de fraude bancario en tiempo real utilizando tecnologías de procesamiento distribuido

OpenAIRE

Mansilla Montero, Javier

2016-01-01

En este Trabajo de Fin de Máster se desarrollará un sistema de detección de fraude en pagos con tarjeta de crédito en tiempo real utilizando tecnologías de procesamiento distribuido. Concretamente se considerarán dos tecnologías: TIBCO, un conjunto de herramientas comerciales diseñadas para el procesamiento de eventos complejos, y Apache Spark, un sistema abierto para el procesamiento de datos en tiempo real. Además de implementar el sistema utilizando las dos tecnologías propuestas, un objet...

Annotating and quantifying pri-miRNA transcripts using RNA-Seq data of wild type and serrate-1 globular stage embryos of Arabidopsis thaliana

Directory of Open Access Journals (Sweden)

Daniel Lepe-Soltero

2017-12-01

Full Text Available The genome annotation for the model plant Arabidopsis thaliana does not include the primary transcripts from which MIRNAs are processed. Here we present and analyze the raw mRNA sequencing data from wild type and serrate-1 globular stage embryos of A. thaliana, ecotype Columbia. Because SERRATE is required for pri-miRNA processing, these precursors accumulate in serrate-1 mutants, facilitating their detection using standard RNA-Seq protocols. We first use the mapping of the RNA-Seq reads to the reference genome to annotate the potential primary transcripts of MIRNAs expressed in the embryo. We then quantify these pri-miRNAs in wild type and serrate-1 mutants. Finally, we use differential expression analysis to determine which are up-regulated in serrate-1 compared to wild type, to select the best candidates for bona fide pri-miRNAs expressed in the globular stage embryos. In addition, we analyze a previously published RNA-Seq dataset of wild type and dicer-like 1 mutant embryos at the globular stage [1]. Our data are interpreted and discussed in a separate article [2].

Annotating and quantifying pri-miRNA transcripts using RNA-Seq data of wild type and serrate-1 globular stage embryos of Arabidopsis thaliana.

Science.gov (United States)

Lepe-Soltero, Daniel; Armenta-Medina, Alma; Xiang, Daoquan; Datla, Raju; Gillmor, C Stewart; Abreu-Goodger, Cei

2017-12-01

The genome annotation for the model plant Arabidopsis thaliana does not include the primary transcripts from which MIRNAs are processed. Here we present and analyze the raw mRNA sequencing data from wild type and serrate-1 globular stage embryos of A. thaliana , ecotype Columbia. Because SERRATE is required for pri-miRNA processing, these precursors accumulate in serrate-1 mutants, facilitating their detection using standard RNA-Seq protocols. We first use the mapping of the RNA-Seq reads to the reference genome to annotate the potential primary transcripts of MIRNAs expressed in the embryo. We then quantify these pri-miRNAs in wild type and serrate-1 mutants. Finally, we use differential expression analysis to determine which are up-regulated in serrate-1 compared to wild type, to select the best candidates for bona fide pri-miRNAs expressed in the globular stage embryos. In addition, we analyze a previously published RNA-Seq dataset of wild type and dicer-like 1 mutant embryos at the globular stage [1]. Our data are interpreted and discussed in a separate article [2].

The galactic globular cluster NGC 1851: its dynamical and evolutionary properties

Science.gov (United States)

Saviane, I.; Piotto, G.; Fagotto, F.; Zaggia, S.; Capaccioli, M.; Aparicio, A.

1998-05-01

We have completely mapped the Galactic globular cluster NGC 1851 with large-field, ground-based VI CCD photometry and pre-repair HST/WFPC1 data for the central region. The photometric data set has allowed a V vs. (V-I) colour-magnitude diagram for ~ 20500 stars to be constructed. >From the apparent luminosity of the horizontal branch (HB) we derive a true distance modulus (m-M)_0 = 15.44 +/- 0.20. An accurate inspection of the cluster's bright and blue objects confirms the presence of seven ``supra-HB'' stars, six of which are identified as evolved descendants from HB progenitors. The HB morphology is found to be clearly bimodal, showing both a red clump and a blue tail, which are not compatible with standard evolutionary models. Synthetic Hertzsprung-Russell (HR) diagrams demonstrate that the problem could be solved by assuming a bimodal efficiency of the mass loss along the red giant branch (RGB). With the aid of Kolmogorov-Smirnov statistics we find evidence that the radial distribution of the blue HB stars is different from that of the red HB and sub-giant branch (SGB) stars. We give the first measurement of the mean absolute I magnitude for 22 known RR Lyr variables ( = 0.12 +/- 0.20 mag at a metallicity [Fe/H] = -1.28). The mean absolute V magnitude is = 0.58 +/- 0.20 mag, and we confirm that these stars are brighter than those of the zero-age HB (ZAHB). Moreover, we found seven new RR Lyr candidates (six ab type and one c type). With these additional variables the ratio of the two types is now N_c/Nab = 0.38. >From a sample of 25 globular clusters a new calibration for Delta V_bump() HB as a function of cluster metallicity is derived. NGC 1851 follows this general trend fairly well. From a comparison with the theoretical models, we also find some evidence for an age-metallicity relation among globular clusters. We identify 13 blue straggler stars, which do not show any sign of variability. The blue stragglers are less concentrated than the subgiant branch

Evaluation of potential use of the wood of Schizolobium amazonicum "Paricá" and Cecropia hololeuca "Embaúba" to particleboard manufacture

OpenAIRE

Iwakiri, Setsuo; Zeller, Florian; Pinto, Juliana Afonso; Ramirez, Maria Guadalupe Lomeli; Souza, Marina Moura; Seixas, Rodrigo

2010-01-01

Esta pesquisa teve por objetivo avaliar o potencial de utilização de madeira de Schizolobium amazonicum (Paricá) e Cecropia hololeuca (Embaúba) para produção de painéis aglomerados. Foram produzidos painéis experimentais com densidade nominal de 0,70 g/cm³, utilizando a resina uréia-formaldeído e partículas de madeira de Paricá e Embaúba, e mistura destas, em proporções de 75, 50 e 25%. A madeira de Pinus taeda foi utilizada como testemunha. Os painéis foram prensados com pressão específica d...

Sulphur in the metal poor globular cluster NGC 6397

Science.gov (United States)

Koch, A.; Caffau, E.

2011-10-01

Sulphur (S) is a non-refractory α-element that is not locked into dust grains in the interstellar medium. Thus no correction to the measured, interstellar sulphur abundance is needed and it can be readily compared to the S content in stellar photospheres. Here we present the first measurement of sulphur in the metal poor globular cluster (GC) NGC 6397, as detected in a MIKE/Magellan high signal-to-noise, high-resolution spectrum of one red giant star. While abundance ratios of sulphur are available for a larger number of Galactic stars down to an [Fe/H] of ~ -3.5 dex, no measurements in globular clusters more metal poor than -1.5 dex have been reported so far. We find aNLTE, 3-D abundance ratio of [S/Fe] = +0.52 ± 0.20 (stat.) ± 0.08 (sys.), based on theS I, Multiplet 1 line at 9212.8 Å. This value is consistent with a Galactic halo plateau as typical of other α-elements in GCs and field stars, but we cannot rule out its membership with a second branch of increasing [S/Fe] with decreasing [Fe/H], claimed in the literature, which leads to a large scatter at metallicities around - 2 dex. The [S/Mg] and [S/Ca] ratios in this star are compatible with a Solar value to within the (large) uncertainties. Despite the very large scatter in these ratios across Galactic stars between literature samples, this indicates that sulphur traces the chemical imprints of the other α-elements in metal poor GCs. Combined with its moderate sodium abundance ([S/Na]NLTE = 0.48), the [S/Fe] ratio in this GC extends a global, positive S-Na correlation that is not seen in field stars and might indicate that proton-capture reactions contributed to the production of sulphur in the (metal poor) early GC environments. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.

X-Ray and optical study of low core density globular clusters NGC6144 and E3

NARCIS (Netherlands)

Lan, S.-H.; Kong, A.K.H.; Verbunt, F.W.M.; Lewin, W.H.G.; Bassa, C.G.; Anderson, S.F.; Pooley, D.

2010-01-01

We report on the Chandra X-ray Observatory and Hubble Space Telescope (HST) observations of two low coredensity globular clusters, NGC6144 and E3. By comparing the number of X-ray sources inside the half-mass radius to those outside, we found six X-ray sources within the half-mass radius of NGC6144,

Multiple populations within globular clusters in Early-type galaxies Exploring their effect on stellar initial mass function estimates

Science.gov (United States)

Chantereau, W.; Usher, C.; Bastian, N.

2018-05-01

It is now well-established that most (if not all) ancient globular clusters host multiple populations, that are characterised by distinct chemical features such as helium abundance variations along with N-C and Na-O anti-correlations, at fixed [Fe/H]. These very distinct chemical features are similar to what is found in the centres of the massive early-type galaxies and may influence measurements of the global properties of the galaxies. Additionally, recent results have suggested that M/L variations found in the centres of massive early-type galaxies might be due to a bottom-heavy stellar initial mass function. We present an analysis of the effects of globular cluster-like multiple populations on the integrated properties of early-type galaxies. In particular, we focus on spectral features in the integrated optical spectrum and the global mass-to-light ratio that have been used to infer variations in the stellar initial mass function. To achieve this we develop appropriate stellar population synthesis models and take into account, for the first time, an initial-final mass relation which takes into consideration a varying He abundance. We conclude that while the multiple populations may be present in massive early-type galaxies, they are likely not responsible for the observed variations in the mass-to-light ratio and IMF sensitive line strengths. Finally, we estimate the fraction of stars with multiple populations chemistry that come from disrupted globular clusters within massive ellipticals and find that they may explain some of the observed chemical patterns in the centres of these galaxies.

EGRET upper limits to the high-energy gamma-ray emission from the millisecond pulsars in nearby globular clusters

Science.gov (United States)

Michelson, P. F.; Bertsch, D. L.; Brazier, K.; Chiang, J.; Dingus, B. L.; Fichtel, C. E.; Fierro, J.; Hartman, R. C.; Hunter, S. D.; Kanbach, G.

1994-01-01

We report upper limits to the high-energy gamma-ray emission from the millisecond pulsars (MSPs) in a number of globular clusters. The observations were done as part of an all-sky survey by the energetic Gamma Ray Experiment Telescope (EGRET) on the Compton Gamma Ray Observatory (CGRO) during Phase I of the CGRO mission (1991 June to 1992 November). Several theoretical models suggest that MSPs may be sources of high-energy gamma radiation emitted either as primary radiation from the pulsar magnetosphere or as secondary radiation generated by conversion into photons of a substantial part of the relativistic e(+/-) pair wind expected to flow from the pulsar. To date, no high-energy emission has been detected from an individual MSP. However, a large number of MSPs are expected in globular cluster cores where the formation rate of accreting binary systems is high. Model predictions of the total number of pulsars range in the hundreds for some clusters. These expectations have been reinforced by recent discoveries of a substantial number of radio MSPs in several clusters; for example, 11 have been found in 47 Tucanae (Manchester et al.). The EGRET observations have been used to obtain upper limits for the efficiency eta of conversion of MSP spin-down power into hard gamma rays. The upper limits are also compared with the gamma-ray fluxes predicted from theoretical models of pulsar wind emission (Tavani). The EGRET limits put significant constraints on either the emission models or the number of pulsars in the globular clusters.

MONTE CARLO SIMULATIONS OF GLOBULAR CLUSTER EVOLUTION. V. BINARY STELLAR EVOLUTION

International Nuclear Information System (INIS)

Chatterjee, Sourav; Umbreit, Stefan; Rasio, Frederic A.; Fregeau, John M.

2010-01-01

We study the dynamical evolution of globular clusters containing primordial binaries, including full single and binary stellar evolution using our Monte Carlo cluster evolution code updated with an adaptation of the single and binary stellar evolution codes SSE and BSE from Hurley et al. We describe the modifications that we have made to the code. We present several test calculations and comparisons with existing studies to illustrate the validity of the code. We show that our code finds very good agreement with direct N-body simulations including primordial binaries and stellar evolution. We find significant differences in the evolution of the global properties of the simulated clusters using stellar evolution compared with simulations without any stellar evolution. In particular, we find that the mass loss from the stellar evolution acts as a significant energy production channel simply by reducing the total gravitational binding energy and can significantly prolong the initial core contraction phase before reaching the binary-burning quasi-steady state of the cluster evolution. We simulate a large grid of models varying the initial cluster mass, binary fraction, and concentration parameter, and we compare properties of the simulated clusters with those of the observed Galactic globular clusters (GGCs). We find that simply including stellar evolution in our simulations and assuming the typical initial cluster half-mass radius is approximately a few pc independent of mass, our simulated cluster properties agree well with the observed GGC properties such as the core radius and the ratio of the core radius to the half-mass radius. We explore in some detail qualitatively different clusters in different phases of their evolution and construct synthetic Hertzsprung-Russell diagrams for these clusters.

The first two transient supersoft X-ray sources in M 31 globular clusters and the connection to classical novae

Czech Academy of Sciences Publication Activity Database

Henze, M.; Pietsch, W.; Haberl, F.; Sala, G.; Quimby, R.; Hernanz, M.; Della Valle, M.; Milne, P.; Williams, G.G.; Burwitz, V.; Greiner, J.; Stiele, H.; Hartmann, D. H.; Kong, A. K. H.; Hornoch, Kamil

2009-01-01

Roč. 500, č. 2 (2009), s. 769-779 ISSN 0004-6361 Institutional research plan: CEZ:AV0Z10030501 Keywords : M 31 * novae * globular clusters Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.179, year: 2009

The gravitational wave emission from white dwarf interactions in globular clusters

International Nuclear Information System (INIS)

Loren-Aguilar, P; Garcia-Berro, E; Lobo, J A; Isern, J

2009-01-01

In the dense central regions of globular clusters close encounters of two white dwarfs are relatively frequent. The estimated frequency is one or more strong encounters per star in the lifetime of the cluster. Such encounters should be then potential sources of gravitational wave radiation. Thus, it is foreseeable that these collisions could be either individually detected by LISA or they could contribute significantly to the background noise of the detector. We compute the pattern of gravitational wave emission from these encounters for a sufficiently broad range of system parameters, namely the masses, the relative velocities and the distances of the two white dwarfs involved in the encounter.

Modelagem da formação e propagação de trincas em misturas asfálticas

Directory of Open Access Journals (Sweden)

Jorge Barbosa Soares

2009-12-01

Full Text Available

O trincamento da camada asfáltica em pavimentos é apontado como o principal defeito das rodovias brasileiras. Estudos experimentais e numéricos sobre este fenômeno vêm sendo realizados considerando o material como homogêneo. Este artigo apresenta uma abordagem numérica baseada na Teoria da Mecânica da Fratura na qual considera-se a heterogeneidade do material, sendo o ligante e os agregados tratados separadamente. As simulações realizadas são verificadas e calibradas através de ensaios laboratoriais simples e convencionais. O estudo trata da formação e propagação de trincas sob carregamentos monotônicos e aponta para uma nova forma de simulação do fenômeno de fadiga de misturas. É ainda discutida a utilização de uma abordagem multi-escala, na qual o dano observado na forma da propagação de trincas na escala local pode ser considerado numa escala global compatível com o pavimento real.

Search for Formation Criteria for Globular Cluster Systems

Science.gov (United States)

Nuritdinov, S. N.; Mirtadjieva, K. T.; Tadjibaev, I. U.

2005-01-01

Star cluster formation is a major mode of star formation in the extreme conditions of interacting galaxies and violent starbursts. By studying ages and metallicities of young metal-enhanced star clusters in mergers / merger remnants we can learn about the violent star formation history of these galaxies and eventually about galaxy formation and evolution. We will present a new set of evolutionary synthesis models of our GALEV code specially developed to account for the gaseous emission of presently forming star clusters and an advanced tool to compare large model grids with multi-color broad-band observations becoming presently available in large amounts. Such observations are an ecomonic way to determine the parameters of young star clusters as will be shown in the presentation. First results of newly-born clusters in mergers and starburst galaxies are presented and compared to the well-studied old globulars and interpreted in the framework of galaxy formation / evolution.

Deep and accurate near-infrared photometry of the Galactic globular cluster omega Cen .

Science.gov (United States)

Calamida, A.; Bono, G.; Corsi, C. E.; Stetson, P. B.; Prada Moroni, P. G.; Degl'Innocenti, S.; Marchetti, E.; Amico, P.; Ferraro, I.; Iannicola, G.; Monelli, M.; Buonanno, R.; Caputo, F.; Dall'Ora, M.; Freyhammer, L. M.; Koester, D.; Nonino, M.; Piersimoni, A. M.; Pulone, L.; Romaniello, M.

We present deep and accurate Near-Infrared (NIR) photometry of the Galactic Globular Cluster omega Cen . Data were collected using the Multi-Conjugate Adaptive Optics Demonstrator (MAD) mounted on the VLT (ESO). We combined the NIR photometry with optical space data collected with the Advanced Camera for Surveys (ACS) for the same region of the cluster. Our deep optical-NIR CMD indicates that the spread in age among the different stellar populations in omega Cen is at most of the order of 2 Gyr.

Características físicas e mecânicas de misturas de solo, cimento e casca de arroz Physical and mechanical characteristics of soil-cement and rice husk mixtures

Directory of Open Access Journals (Sweden)

Ana P. S. Milani

2006-04-01

Full Text Available Na presente pesquisa, estudaram-se os efeitos da adição da casca de arroz nas propriedades físico-mecânicas da mistura de solo-cimento, visando a obter composições de solo-cimento-casca de arroz com potencialidade para fabricação de materiais alternativos de construção. Foram realizados o fracionamento, o peneiramento e o pré-tratamento em solução de cal da casca de arroz. Foram determinadas as características físicas do solo e da casca de arroz, sendo executados ensaios de dosagem das misturas de solo-cimento-casca de arroz, aplicando-se às mesmas os ensaios de compactação normal de Proctor e o de compressão simples. Posteriormente, as composições de solo-cimento-casca de arroz foram submetidas aos ensaios de compressão simples e de tração na compressão diametral, aos 7 e aos 28 dias de idade, e de absorção d'água. Depois de determinadas as principais características físicas e mecânicas, pôde-se concluir que as misturas de solo + teor de 12% de combinações de cimento e casca de arroz se apresentaram como materiais promissores para a fabricação de elementos construtivos, a serem utilizados em construções e instalações rurais.The main objective of this work is the study of the effect of rice husk addition on the physical and mechanical properties of soil-cement, in order to obtain an alternative construction material. The rice husk preparation consisted of grinding, sieving, and the pre-treatment with lime solution. The physical characteristics of the soil and of the rice husk were determined. Different amounts of soil, cement and rice husk were tested by compaction and unconfined compression. The specimens molded according to the treatments applied to the mixtures were subsequently submitted to compression testing and to tensile splitting cylinder testing at 7 and 28 days of age and to water absorption testing. After determining its physical and mechanical characteristics, the best results were obtained

Neutron-Capture Element Abundances in the Globular Cluster M15.

Science.gov (United States)

Sneden; Johnson; Kraft; Smith; Cowan; Bolte

2000-06-20

High-resolution, high signal-to-noise ratio, blue-violet spectra of three red giant branch tip stars in M15 have been obtained with the Keck I High-Resolution Echelle Spectrograph. These spectra have been analyzed to determine the abundances of several neutron-capture elements, including the radioactive chronometer element thorium. There are two principal results of this study. First, the abundances of the heavier (Z>/=56) elements for each of the three stars is well matched by a scaled solar system r-process abundance distribution. Second, a weighted mean-observed Th/Eu ratio for the stars implies an age for the neutron-capture material in M15 stars of 14+/-3 Gyr, in reasonable agreement with other recent age estimates for Galactic globular clusters.

Globular adiponectin ameliorates metabolic insulin resistance via AMPK-mediated restoration of microvascular insulin responses

Science.gov (United States)

Zhao, Lina; Fu, Zhuo; Wu, Jing; Aylor, Kevin W; Barrett, Eugene J; Cao, Wenhong; Liu, Zhenqi

2015-01-01

Abstract Hypoadiponectinaemia is closely associated with endothelial dysfunction and insulin resistance, and microvasculature plays a critical role in the regulation of insulin action in muscle. Here we tested whether adiponectin replenishment could improve metabolic insulin sensitivity in male rats fed a high-fat diet (HFD) via the modulation of microvascular insulin responses. Male Sprague–Dawley rats were fed either a HFD or low-fat diet (LFD) for 4 weeks. Small resistance artery myograph changes in tension, muscle microvascular recruitment and metabolic response to insulin were determined. Compared with rats fed a LFD, HFD feeding abolished the vasodilatory actions of globular adiponectin (gAd) and insulin on pre-constricted distal saphenous arteries. Pretreatment with gAd improved insulin responses in arterioles isolated from HFD rats, which was blocked by AMP-activated protein kinase (AMPK) inhibition. Similarly, HFD abolished microvascular responses to either gAd or insulin and decreased insulin-stimulated glucose disposal by ∼60%. However, supplementing gAd fully rescued insulin’s microvascular action and significantly improved the metabolic responses to insulin in HFD male rats and these actions were abolished by inhibition of either AMPK or nitric oxide production. We conclude that HFD induces vascular adiponectin and insulin resistance but gAd administration can restore vascular insulin responses and improve insulin’s metabolic action via an AMPK- and nitric oxide-dependent mechanism in male rats. Key points Adiponectin is an adipokine with anti-inflammatory and anti-diabetic properties. Hypoadiponectinaemia is closely associated with endothelial dysfunction and insulin resistance in obesity and diabetes. Insulin resistance is present in muscle microvasculature and this may contribute to decreased insulin delivery to, and action in, muscle. In this study we examined whether adiponectin ameliorates metabolic insulin resistance by affecting muscle

BVI CCD photometry of the globular cluster M4

International Nuclear Information System (INIS)

Alcaino, G.; Liller, W.; Alvarado, F.

1988-01-01

CCD BV1 main-sequence (MS) photometry of M4, the globular cluster closest to the sun, is presented. The photometry is matched to the BVI isochrones of VandenBerg and Bell (1985). The MS turnoffs are found to be at V = 16.90 + or - 0.05, B-V = 0.81 + or - 0.02, V-I = 0.96 + or - 0.02, and B - I = 1.77 + or - 0.02. The magnitude difference between the MS turnoff and the horizontal branch is Delta M(V) = 3.52 + or - 0.1 for all three color indices. Using Y = 0.2, (Fe/H) = - 1.27, and alpha = 1.65, with a distance modulus of (m-M)V = 12.7 and E(B-V) = 0.41, a consistent age for M4 is deduced in all three color indices of 17 + or - 1.5 Gyr. 34 references

Cyanogen strengths of globular cluster post-main-sequence stars

International Nuclear Information System (INIS)

Hesser, J.E.; Hartwick, F.D.A.; McClure, R.D.

1976-01-01

CN strengths in the peculiar clusters ω Cen and M22 and the metal-rich clusters 47 Tuc, M71, and NGC 6352 are found to vary markedly from star to star. The strong variations in CN strength found earlier for ω Cen by Norris and Bessell and by Dickens and Bell are shown to extend to fainter stars, although expected correlations of CN strength with position in the color-magnitude (C-M) diagram are less evident in our sample. Several CN and metal-strong stars were also observed in M22. We conclude that CN, once it appears in globular clusters, can vary much more than it does in equivalent Population I samples, a result we briefly examine in light of current understanding regarding physical processes in the stars themselves and of models of galactic chemical evolution

Estudo da durabilidade de misturas solo-RBI grade 81 com vistas à aplicação em estradas florestais e camadas de pavimentos convencionais Study of durability of soil-RBI grade 81 mixtures for application in forest roads and convencional pavement layers

Directory of Open Access Journals (Sweden)

Tiago Pinto da Trindade

2005-08-01

Full Text Available O presente artigo foi dirigido à caracterização, para fins rodoviários, do parâmetro durabilidade de três misturas solo-RBI Grade 81, a partir dos resultados dos ensaios de durabilidade por molhagem e secagem. Trabalhou-se com um solo residual maduro (solo 1 e dois solos residuais jovens (solos 2 e 3 de gnaisse da Zona da Mata Norte de Minas Gerais, Brasil. O programa de ensaios de laboratório envolveu: (i teor de RBI Grade 81: 6% em relação ao peso de solo seco; (ii energias de compactação: Proctor Normal, Intermediário e Modificado; e (iii período de cura: 7 dias em câmara úmida. Os resultados do programa de ensaios apontaram que: (i apenas as misturas dos solos 1 e 3 compactadas na energia do ensaio Proctor Intermediário e dos solos 2 e 3 compactadas na energia do ensaio Proctor Modificado resistiram a todos os ciclos do ensaio de durabilidade por secagem e molhagem; (ii as misturas do solo 3 compactadas na energia do ensaio Proctor Modificado apresentaram as menores perdas de massa (inferiores a 13%; e (iii quanto ao aspecto durabilidade, as misturas solo-RBI Grade 81 exibem bom potencial para emprego como material de construção rodoviária.This paper addresses the characterization of three soil-RBI Grade 81 mixtures for road engineering applications using laboratory testing data from wetting and drying durability tests. One mature (soil 1 and two young (soils 2 and 3 gneiss residual soils from the Zona da Mata Norte de Minas Gerais, Brazil, were used throughout the study. The laboratory testing program comprised the following steps: (i RBI Grade 81 content: 6% regarding soil dry mass; (ii compaction efforts: Standard, Intermediate and Modified Proctor; (iii mixture specimens curing time: 7 days in acclimatized room. The testing program data supported that: (i only tested mixtures of soils 1 and 3 compacted at the Intermediate compaction effort, and of soils 2 and 3 compacted at the Modified compaction effort endured all

A KINETIC MODEL FOR MONO-LAYER GLOBULAR PROTEIN ADSORPTION ON SOLID/LIQUID INTERFACES

Directory of Open Access Journals (Sweden)

Kamal I. M. Al-Malah

2012-12-01

Full Text Available A kinetic model was derived for globular protein adsorption. The model takes into account the three possible scenarios of a protein molecule in solution, being exposed to an interface: adsorption step from the solution to the interface; the possible desorption back into the solution; and the surface-induced unfolding or spreading of the protein unto the substrate surface. A globular protein molecule is visualized as a sphere with radius D. In addition to the general case of protein adsorption, which portrays either the surface coverage (Theta or surface concentration (� as a function of the adsorption time, special cases, like equilibrium condition, lowsurface coverage, irreversible, and Langmuirian were also presented and treated in light of the derived model. The general model was simplified for each of the subset cases. The irreversibility versus reversibility of protein adsorption was discussed. The substrate surface energetics or effects are accounted for via the proposition of the percent relative change in D/V ratio for the adsorbing protein, called (D/VPRC parameter. (D/VPRC is calculated with respect to the monolayer surface concentration of protein, where the latter is given by D/Vratio. This can be used as a landmark to protein adsorption isotherms or even kinetics. This is visualized as an indicator for solid substrate effects on the adsorbing proteins. (D/VPRC can be zero (fresh monolayer, negative (aged monolayer, or positive (multi-layer. The reference surface concentration is reported for some selected proteins.

Globular adiponectin induces a pro-inflammatory response in human astrocytic cells

International Nuclear Information System (INIS)

Wan, Zhongxiao; Mah, Dorrian; Simtchouk, Svetlana; Klegeris, Andis; Little, Jonathan P.

2014-01-01

Highlights: • Adiponectin receptors are expressed in human astrocytes. • Globular adiponectin induces secretion of IL-6 and MCP-1 from cultured astrocytes. • Adiponectin may play a pro-inflammatory role in astrocytes. - Abstract: Neuroinflammation, mediated in part by activated brain astrocytes, plays a critical role in the development of neurodegenerative disorders, including Alzheimer’s disease (AD). Adiponectin is the most abundant adipokine secreted from adipose tissue and has been reported to exert both anti- and pro-inflammatory effects in peripheral tissues; however, the effects of adiponectin on astrocytes remain unknown. Shifts in peripheral concentrations of adipokines, including adiponectin, could contribute to the observed link between midlife adiposity and increased AD risk. The aim of the present study was to characterize the effects of globular adiponectin (gAd) on pro-inflammatory cytokine mRNA expression and secretion in human U373 MG astrocytic cells and to explore the potential involvement of nuclear factor (NF)-κB, p38 mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinase (ERK)1/2, c-Jun N-terminal kinase (JNK) and phosphatidylinositide 3-kinases (PI3 K) signaling pathways in these processes. We demonstrated expression of adiponectin receptor 1 (adipoR1) and adipoR2 in U373 MG cells and primary human astrocytes. gAd induced secretion of interleukin (IL)-6 and monocyte chemoattractant protein (MCP)-1, and gene expression of IL-6, MCP-1, IL-1β and IL-8 in U373 MG cells. Using specific inhibitors, we found that NF-κB, p38MAPK and ERK1/2 pathways are involved in gAd-induced induction of cytokines with ERK1/2 contributing the most. These findings provide evidence that gAd may induce a pro-inflammatory phenotype in human astrocytes

Globular adiponectin induces a pro-inflammatory response in human astrocytic cells

Energy Technology Data Exchange (ETDEWEB)

Wan, Zhongxiao; Mah, Dorrian; Simtchouk, Svetlana [School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, BC (Canada); Klegeris, Andis [Department of Biology, University of British Columbia Okanagan, Kelowna, BC (Canada); Little, Jonathan P., E-mail: jonathan.little@ubc.ca [School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, BC (Canada)

2014-03-28

Highlights: • Adiponectin receptors are expressed in human astrocytes. • Globular adiponectin induces secretion of IL-6 and MCP-1 from cultured astrocytes. • Adiponectin may play a pro-inflammatory role in astrocytes. - Abstract: Neuroinflammation, mediated in part by activated brain astrocytes, plays a critical role in the development of neurodegenerative disorders, including Alzheimer’s disease (AD). Adiponectin is the most abundant adipokine secreted from adipose tissue and has been reported to exert both anti- and pro-inflammatory effects in peripheral tissues; however, the effects of adiponectin on astrocytes remain unknown. Shifts in peripheral concentrations of adipokines, including adiponectin, could contribute to the observed link between midlife adiposity and increased AD risk. The aim of the present study was to characterize the effects of globular adiponectin (gAd) on pro-inflammatory cytokine mRNA expression and secretion in human U373 MG astrocytic cells and to explore the potential involvement of nuclear factor (NF)-κB, p38 mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinase (ERK)1/2, c-Jun N-terminal kinase (JNK) and phosphatidylinositide 3-kinases (PI3 K) signaling pathways in these processes. We demonstrated expression of adiponectin receptor 1 (adipoR1) and adipoR2 in U373 MG cells and primary human astrocytes. gAd induced secretion of interleukin (IL)-6 and monocyte chemoattractant protein (MCP)-1, and gene expression of IL-6, MCP-1, IL-1β and IL-8 in U373 MG cells. Using specific inhibitors, we found that NF-κB, p38MAPK and ERK1/2 pathways are involved in gAd-induced induction of cytokines with ERK1/2 contributing the most. These findings provide evidence that gAd may induce a pro-inflammatory phenotype in human astrocytes.

A Deep X-ray Survey of the Globular Cluster Omega Centauri

Science.gov (United States)

Henleywillis, Simon; Cool, Adrienne M.; Haggard, Daryl; Heinke, Craig; Callanan, Paul; Zhao, Yue

2018-03-01

We identify 233 X-ray sources, of which 95 are new, in a 222 ks exposure of Omega Centauri with the Chandra X-ray Observatory's ACIS-I detector. The limiting unabsorbed flux in the core is fX(0.5-6.0 keV) ≃ 3×10-16 erg s-1 cm-2 (Lx ≃ 1×1030 erg s-1 at 5.2 kpc). We estimate that ˜60 ± 20 of these are cluster members, of which ˜30 lie within the core (rc = 155 arcsec), and another ˜30 between 1-2 core radii. We identify four new optical counterparts, for a total of 45 likely identifications. Probable cluster members include 18 cataclysmic variables (CVs) and CV candidates, one quiescent low-mass X-ray binary, four variable stars, and five stars that are either associated with ω Cen's anomalous red giant branch, or are sub-subgiants. We estimate that the cluster contains 40 ± 10 CVs with Lx > 1031 erg s-1, confirming that CVs are underabundant in ω Cen relative to the field. Intrinsic absorption is required to fit X-ray spectra of six of the nine brightest CVs, suggesting magnetic CVs, or high-inclination systems. Though no radio millisecond pulsars (MSPs) are currently known in ω Cen, more than 30 unidentified sources have luminosities and X-ray colours like those of MSPs found in other globular clusters; these could be responsible for the Fermi-detected gamma-ray emission from the cluster. Finally, we identify a CH star as the counterpart to the second-brightest X-ray source in the cluster and argue that it is a symbiotic star. This is the first such giant/white dwarf binary to be identified in a globular cluster.

Efeito de produtos alternativos para o controle do bolor verde (Penicillium digitatum em pós-colheita de citros Effect of the alternative products for control of green mold (Penicillium digitatum in post-harvest citrus fruit

Directory of Open Access Journals (Sweden)

DANIEL ANDRADE DE SIQUEIRA FRANCO

2002-08-01

Full Text Available O objetivo do trabalho foi verificar a ocorrência de sinergismo entre misturas de produtos alternativos aos fungicidas, para o controle do bolor verde (Penicillium digitatum em pós-colheita de citros. Foram testados dez produtos individualmente e trinta e cinco combinações destes produtos dois a dois, em comparação com tiabendazole e testemunha, com e sem inoculação. Os produtos testados não apresentaram efeito de sinergismo, exceto a mistura carbonato de Na + ácido bórico. Carbonato de Na e ácido bórico controlaram a doença em 78 e 87%, respectivamente, e, utilizando a mistura, o controle foi de 93%. Destacaram-se, ainda no controle da doença, o bicarbonato de Na, metabissulfito de Na e as misturas de bicarbonato de sódio + ácido bórico, carbonato de Na + carbonato de K, carbonato de Na + sorbato de K, bicarbonato de Na + carbonato de Na, controlando 92; 77; 81; 77; 75 e 71%, respectivamente. O tiabendazole utilizado como padrão controlou totalmente a doença.The objective of this work was verify the ocurrence of synergism of mixtures for alternative products to the fungicides for the control of the green mold (Penicillium digitatum in post-harvest citrus fruits. The efficiency of ten products, tested individually, and thirty five combinations among them, in pairs, were compared to thiabendazole and control, with and without inoculation. The products didn't present a synergism effect, except the mixture sodium carbonate + boric acid, that had a disease control of 93%. The products, sodium carbonate and boric acid controled 78 and 87%, respectively. The sodium bicarbonate, sodium methabisulphite and the mixtures of sodium bicarbonate + boric acid, sodium carbonate + potassium carbonate, sodium carbonate + potassium sorbate, sodium bicarbonate + sodium carbonate had a disease control of 92%, 77%, 81%, 77%, 75% and 71%, respectively. The fungicide treatment with thiabendazole used by standard had a whole disease control.

Discovery of a 205.89 Hz accreting millisecond X-ray pulsar in the globular cluster NGC 6440

NARCIS (Netherlands)

Altamirano, D.; Patruno, A.; Heinke, C.O.; Markwardt, C.; Strohmayer, T.E.; Linares, M.; Wijnands, R.; van der Klis, M.; Swank, J.H.

2010-01-01

We report on the discovery of the second accreting millisecond X-ray pulsar (AMXP) in the globular cluster NGC 6440. Pulsations with a frequency of 205.89 Hz were detected with RXTE on 2009 August 30, October 1 and October 28, during the decays of less than or similar to 4 day outbursts of a newly

Color-magnitude diagrams for six metal-rich, low-latitude globular clusters

Science.gov (United States)

Armandroff, Taft E.

1988-01-01

Colors and magnitudes for stars on CCD frames for six metal-rich, low-latitude, previously unstudied globular clusters and one well-studied, metal-rich cluster (47 Tuc) have been derived and color-magnitude diagrams have been constructed. The photometry for stars in 47 Tuc are in good agreement with previous studies, while the V magnitudes of the horizontal-branch stars in the six program clusters do not agree with estimates based on secondary methods. The distances to these clusters are different from prior estimates. Redding values are derived for each program cluster. The horizontal branches of the program clusters all appear to lie entirely redwards of the red edge of the instability strip, as is normal for their metallicities.

WHERE ARE MOST OF THE GLOBULAR CLUSTERS IN TODAY’S UNIVERSE?

Energy Technology Data Exchange (ETDEWEB)

Harris, William E., E-mail: harris@physics.mcmaster.ca [Department of Physics and Astronomy, McMaster University, Hamilton, ON (Canada)

2016-04-15

The total number of globular clusters (GCs) in a galaxy rises continuously with the galaxy luminosity L, while the relative number of galaxies decreases with L following the Schechter function. The product of these two very nonlinear functions gives the relative number of GCs contained by all galaxies at a given L. It is shown that GCs, in this universal sense, are most commonly found in galaxies within a narrow range around L{sub ⋆}. In addition, blue (metal-poor) GCs outnumber the red (metal-richer) ones globally by 4 to 1 when all galaxies are added, pointing to the conclusion that the earliest stages of galaxy formation were especially favorable to forming massive, dense star clusters.

The X-ray globular cluster NGC 1851

CERN Document Server

Alcaino, G

1976-01-01

A BV photometric investigation of the Southern Globular Cluster NGC 1851, was carried out using the 1 m telescope of Cerro La Silla (ESO) for the photoelectric work and the 1 m telescope of Cerro Las Campanas (CARSO) for the photographic work. Nineteen stars were observed photoelectrically, the limiting magnitude being V=16.18. Using this sequence, 156 stars were measured photographically. The derived apparent distance modulus is (m-M)/sub app/=15/sup m/.50. The reddening is E(B-V)=0/sup m/.10. The true distance modulus is (m-M) /sub 0/=15/sup m/.20. The distance is 11 kpc from the sun, 6 kpc from the galactic plane and 17 kpc from the galactic centre. The main features of the colour-magnitude diagram are: a well defined horizontal branch abundant in red stars and deficient in blue stars, a rich subgiant and asymptotic branch and a moderately populated red giant branch of medium steepness rising to Delta V=2/sup m/.5 at (B-V) /sub 0/=1.4. At the distance of 11 kpc the maximum observed luminosity of the X-ray ...

CENTRAL ROTATIONS OF MILKY WAY GLOBULAR CLUSTERS

International Nuclear Information System (INIS)

Fabricius, Maximilian H.; Rukdee, Surangkhana; Saglia, Roberto P.; Bender, Ralf; Hopp, Ulrich; Thomas, Jens; Williams, Michael J.; Noyola, Eva; Opitsch, Michael

2014-01-01

Most Milky Way globular clusters (GCs) exhibit measurable flattening, even if on a very low level. Both cluster rotation and tidal fields are thought to cause this flattening. Nevertheless, rotation has only been confirmed in a handful of GCs, based mostly on individual radial velocities at large radii. We are conducting a survey of the central kinematics of Galactic GCs using the new Integral Field Unit instrument VIRUS-W. We detect rotation in all 11 GCs that we have observed so far, rendering it likely that a large majority of the Milky Way GCs rotate. We use published catalogs of GCs to derive central ellipticities and position angles. We show that in all cases where the central ellipticity permits an accurate measurement of the position angle, those angles are in excellent agreement with the kinematic position angles that we derive from the VIRUS-W velocity fields. We find an unexpected tight correlation between central rotation and outer ellipticity, indicating that rotation drives flattening for the objects in our sample. We also find a tight correlation between central rotation and published values for the central velocity dispersion, most likely due to rotation impacting the old dispersion measurements

SHRINKING THE BRANEWORLD: BLACK HOLE IN A GLOBULAR CLUSTER

International Nuclear Information System (INIS)

Gnedin, Oleg Y.; Maccarone, Thomas J.; Psaltis, Dimitrios; Zepf, Stephen E.

2009-01-01

Large extra dimensions have been proposed as a possible solution to the hierarchy problem in physics. In one of the suggested models, the RS2 braneworld model, black holes may evaporate by Hawking radiation faster than in general relativity, on a timescale that depends on the black hole mass and on the asymptotic radius of curvature of the extra dimensions. Thus the size of the extra dimensions can be constrained by astrophysical observations. Here we point out that the black hole, recently discovered in an extragalactic globular cluster, places the strongest upper limit on the size of the extra dimensions in the RS2 model, L ∼< 0.003 mm. This black hole has the virtues of old age and relatively small mass. The derived upper limit is within an order of magnitude of the absolute limit afforded by astrophysical observations of black holes.

A Stochastic mesoscopic model for predicting the globular grain structure and solute redistribution in cast alloys at low superheat

International Nuclear Information System (INIS)

Nastac, Laurentiu; El Kaddah, Nagy

2012-01-01

It is well known that casting at low superheat has a strong influence on the solidification morphology and macro- and microstructures of the cast alloy. This paper describes a stochastic mesoscopic solidification model for predicting the grain structure and segregation in cast alloy at low superheat. This model was applied to predict the globular solidification morphology and size as well as solute redistribution of Al in cast Mg AZ31B alloy at superheat of 5°C produced by the Magnetic Suspension Melting (MSM) process, which is an integrated containerless induction melting and casting process. The castings produced at this low superheat have fine globular grain structure, with an average grain size of 80 μm, which is about 3 times smaller than that obtained by conventional casting techniques. The stochastic model was found to reasonably predict the observed grain structure and Al microsegregation. This makes the model a useful tool for controlling the structure of cast magnesium alloys.

A SPECTROSCOPIC ANALYSIS OF THE GALACTIC GLOBULAR CLUSTER NGC 6273 (M19)

Energy Technology Data Exchange (ETDEWEB)

Johnson, Christian I.; Caldwell, Nelson [Harvard–Smithsonian Center for Astrophysics, 60 Garden Street, MS-15, Cambridge, MA 02138 (United States); Rich, R. Michael [Department of Physics and Astronomy, UCLA, 430 Portola Plaza, Box 951547, Los Angeles, CA 90095-1547 (United States); Pilachowski, Catherine A. [Astronomy Department, Indiana University Bloomington, Swain West 319, 727 East 3rd Street, Bloomington, IN 47405-7105 (United States); Mateo, Mario; Bailey, John I. III [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States); Crane, Jeffrey D., E-mail: cjohnson@cfa.harvard.edu, E-mail: ncaldwell@cfa.harvard.edu, E-mail: rmr@astro.ucla.edu, E-mail: catyp@astro.indiana.edu, E-mail: mmateo@umich.edu, E-mail: baileyji@umich.edu, E-mail: crane@obs.carnegiescience.edu [The Observatories of the Carnegie Institution for Science, Pasadena, CA 91101 (United States)

2015-08-15

A combined effort utilizing spectroscopy and photometry has revealed the existence of a new globular cluster class. These “anomalous” clusters, which we refer to as “iron-complex” clusters, are differentiated from normal clusters by exhibiting large (≳0.10 dex) intrinsic metallicity dispersions, complex sub-giant branches, and correlated [Fe/H] and s-process enhancements. In order to further investigate this phenomenon, we have measured radial velocities and chemical abundances for red giant branch stars in the massive, but scarcely studied, globular cluster NGC 6273. The velocities and abundances were determined using high resolution (R ∼ 27,000) spectra obtained with the Michigan/Magellan Fiber System (M2FS) and MSpec spectrograph on the Magellan–Clay 6.5 m telescope at Las Campanas Observatory. We find that NGC 6273 has an average heliocentric radial velocity of +144.49 km s{sup −1} (σ = 9.64 km s{sup −1}) and an extended metallicity distribution ([Fe/H] = −1.80 to −1.30) composed of at least two distinct stellar populations. Although the two dominant populations have similar [Na/Fe], [Al/Fe], and [α/Fe] abundance patterns, the more metal-rich stars exhibit significant [La/Fe] enhancements. The [La/Eu] data indicate that the increase in [La/Fe] is due to almost pure s-process enrichment. A third more metal-rich population with low [X/Fe] ratios may also be present. Therefore, NGC 6273 joins clusters such as ω Centauri, M2, M22, and NGC 5286 as a new class of iron-complex clusters exhibiting complicated star formation histories.

Produtos extrusados expandidos de misturas de canjiquinha e soja para uso como petiscos

Directory of Open Access Journals (Sweden)

Fernandes Marilene dos Santos

2002-01-01

Full Text Available O objetivo deste trabalho foi estudar o efeito da temperatura de barril (TB do extrusor no índice de expansão (IE e no índice de solubilidade em água (ISA dos produtos extrusados expandidos de misturas de canjiquinha e soja (80:20 e 70:30, e verificar suas características sensoriais, quando aromatizado para uso como petiscos. Foi usado o extrusor Brabender de dupla-rosca, com velocidade de alimentação constante de 20,8 kg/h, velocidade da rotação de parafuso de 100 rpm e diâmetro de matriz de 5 mm. As temperaturas de barril do extrusor foram constantes na zona 1 (60masculineC e na zona 2 (90masculineC e variáveis na zona 3 (90, 110, 130 e 150masculineC e na zona 4 (110, 130 e 150masculineC. O IE e o ISA dos produtos extrusados expandidos aumentaram com o aumento da TB na zona 3 até 110masculineC; acima desta temperatura, observou-se diminuição desses índices. O aumento da TB na zona 4 resultou em aumento no IE e ISA, exceto quando os produtos haviam sido submetidos a 130 e 150masculineC na zona 3. O produto extrusado expandido contendo 80% de canjiquinha e 20% de soja, submetido às temperaturas de barril de 60, 90, 110 e 150masculineC e aromatizado com cebola, apresentou melhor aparência, textura e sabor, e foi preferido pelos consumidores. Não houve atividade do inibidor de tripsina nos produtos estudados.

Avaliação do processo de coagulação-floculação de lixiviado de aterro sanitário pré-tratado biologicamente utilizando quitosana e sulfato de alumínio como coagulantes

Directory of Open Access Journals (Sweden)

Inara Do Carmo Oliveira Nascimento

2015-12-01

Full Text Available Os lixiviados de aterros sanitários apresentam elevadas concentrações de nitrogênio amoniacal, matéria orgânica biodegradável e compostos recalcitrantes, que não permitem seu descarte no meio ambiente sem tratamento prévio. Como alternativa complementar ao tratamento biológico desse efluente, diferentes processos físico-químicos têm sido desenvolvidos para reduzir as concentrações de matéria orgânica recalcitrante presentes nos lixiviados de aterro sanitário. Para tanto, a presente pesquisa buscou avaliar a eficiência do processo de coagulação-floculação quanto à remoção dessa matéria orgânica presente em lixiviado pré-tratado biologicamente utilizando quitosana e sulfato de alumínio como coagulantes. Durante a realização dos ensaios, o efluente coletado de um sistema de lodo ativado operado em bateladas seqüenciais em escala piloto, instalado na área do Aterro Sanitário Integrado Camaçari e Dias D’avila, foi submetido ao tratamento físico-químico com os coagulantes quitosana e sulfato de alumínio (Al2(SO43.14 H2O em equipamento de testes de jarros. Para avaliar a eficiência do processo físico-químico, foi aplicada a metodologia estatística de planejamento experimental, a fim de obter as melhores condições de processo que fornecessem eficiências de remoção significativas da matéria orgânica recalcitrante por meio dos parâmetros cor verdadeira e turbidez. Posteriormente, foram realizados alguns ensaios de toxicidade aguda com Lemna minor e Poecilia reticulata. Os resultados mostraram que, nas faixas testadas, apenas as variáveis de controle concentração de coagulante (C e o valor do pH de dosagem foram significativas para o processo, uma vez que as condições de mistura (Gmr, Gf, Tmr e Tf não influenciaram nas variáveis respostas. Utilizando a quitosana como coagulante, alcançou-se valores médios de eficiência de remoção de cor verdadeira e turbidez iguais a 73% e 94

Uma Abordagem de Monitoração de Tráfego de Rede utilizando Lógica Difusa

OpenAIRE

Silveira, Enio Rovere; Universidade Federal de Santa Catarina; Dantas, M. A.R.; Universidade Federal de Santa Catarina

2005-01-01

Neste artigo, apresentamos um trabalho de pesquisa de monitoração de tráfego de rede utilizando uma abordagem de lógica difusa. Nossa contribuição está focada na criação de um protótipo que pudesse ser avaliado em uma configuração real de produção de uma grande organização, utilizando-se de hardware e software existentes na empresa. Resultados experimentais obtidos através de estudos de casos reais no ambiente, indicam o sucesso da abordagem na melhoria da monitoração de tráfego da rede....

THE HUBBLE SPACE TELESCOPE UV LEGACY SURVEY OF GALACTIC GLOBULAR CLUSTERS. VII. IMPLICATIONS FROM THE NEARLY UNIVERSAL NATURE OF HORIZONTAL BRANCH DISCONTINUITIES

Energy Technology Data Exchange (ETDEWEB)

Brown, T. M.; Bellini, A.; Anderson, J. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Cassisi, S.; Pietrinferni, A. [INAF-Osservatorio Astronomico di Teramo, Via Mentore Maggini s.n.c., I-64100 Teramo (Italy); D’Antona, F. [INAF-Osservatorio Astronomico di Roma, Via Frascati 33, I-00040 Monteporzio Catone, Roma (Italy); Salaris, M. [Astrophysics Research Institute,Liverpool John Moores University, Liverpool Science Park, IC2 Building, 146 Brownlow Hill, Liverpool L3 5RF (United Kingdom); Milone, A. P. [Research School of Astronomy and Astrophysics, The Australian National University, Cotter Road, Weston, ACT, 2611 (Australia); Dalessandro, E. [Dipartimento di Fisica e Astronomia, Università degli Studi di Bologna, Viale Berti Pichat 6/2, I-40127 Bologna (Italy); Piotto, G.; Ortolani, S.; Nardiello, D. [Dipartimento di Fisica e Astronomia “Galileo Galilei,”Università di Padova, Vicolo dell’Osservatorio 3, I-35122 Padova (Italy); Renzini, A.; Bedin, L. R. [INAF-Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, I-35122 Padova (Italy); Sweigart, A. V. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Sarajedini, A. [Department of Astronomy, University of Florida, 211 Bryant Space Science Center, Gainesville, FL 32611 (United States); Aparicio, A., E-mail: tbrown@stsci.edu, E-mail: jayander@stsci, E-mail: bellini@stsci.edu, E-mail: cassisi@oa-teramo.inaf.it, E-mail: pietrinferni@oa-teramo.inaf.it, E-mail: dantona@oa-roma.inaf.it, E-mail: M.Salaris@ljmu.ac.uk, E-mail: milone@mso.anu.edu.au [Instituto de Astrofísica de Canarias. Calle Vía Láctea s/n. E38200 — La Laguna, Tenerife, Canary Islands (Spain)

2016-05-01

The UV-initiative Hubble Space Telescope Treasury survey of Galactic globular clusters provides a new window into the phenomena that shape the morphological features of the horizontal branch (HB). Using this large and homogeneous catalog of UV and blue photometry, we demonstrate that the HB exhibits discontinuities that are remarkably consistent in color (effective temperature). This consistency is apparent even among some of the most massive clusters hosting multiple distinct sub-populations (such as NGC 2808, ω Cen, and NGC 6715), demonstrating that these phenomena are primarily driven by atmospheric physics that is independent of the underlying population properties. However, inconsistencies arise in the metal-rich clusters NGC 6388 and NGC 6441, where the discontinuity within the blue HB (BHB) distribution shifts ∼1000–2000 K hotter. We demonstrate that this shift is likely due to a large helium enhancement in the BHB stars of these clusters, which in turn affects the surface convection and evolution of such stars. Our survey also increases the number of Galactic globular clusters known to host blue-hook stars (also known as late hot flashers) from 6 to 23 clusters. These clusters are biased toward the bright end of the globular cluster luminosity function, confirming that blue-hook stars tend to form in the most massive clusters with significant self-enrichment.

Seletividade de cultivares de soja RR® submetidos a misturas em tanque de glyphosate + chlorimuron-ethyl associadas a óleo mineral e inseticidas selectivity of soybean RR® genotypes submitted to glyphosate + chlorimuron-ethyl tank mixtures associated to mineral oil and insecticides

Directory of Open Access Journals (Sweden)

C.D.G. Maciel

2009-01-01

Full Text Available O uso de glyphosate para o controle de plantas daninhas em soja RR® apresenta características essenciais no conceito de praticabilidade. Entretanto, apesar de não permitido na legislação brasileira, tem-se aumentado a associação com outros herbicidas para manejo de espécies de difícil controle, assim como a sua mistura em tanque em combinação com inseticidas e adjuvantes. Com o objetivo de avaliar a seletividade de cultivares de soja RR® submetidos a misturas em tanque de formulações de glyphosate (Polaris®, Roundup Ready® e Roundup WG® com chlorimuron-ethyl (Classic®, e suas associações com óleo mineral (Joint Oil® e inseticidas novaluron (Gallaxy 100 EC®, permethrin (Piredan® e methomyl (Lannate BR®, um experimento foi conduzido a campo na cidade de Maracaí-SP, na safra 2006/2007. O delineamento experimental utilizado foi o de blocos ao acaso, com quatro repetições, em esquema fatorial 16 x 4, sendo 16 as associações das misturas em tanque entre as formulações de glyphosate, óleo mineral e inseticidas e quatro cultivares: Monsoy 7210RR®, Monsoy 7979RR®, BRS 245RR® e CD 214RR®. Sintomas visuais de intoxicação inicial dos cultivares estudados foram caracterizados por clorose e encarquilhamento nas folhas para todas as misturas em tanque das formulações de glyphosate + chlorimuron-ethyl, associadas ou não ao óleo mineral e inseticidas novaluron, permethrin e methomyl. Todas as misturas em tanque não promoveram reduções significativas de produtividade para os cultivares Monsoy 7210RR®, Monsoy 7979RR® e BRS 245RR® e controlaram Ipomoea spp. com eficácia apenas satisfatória a partir dos 21 DAA (dias após aplicação.The use of glyphosate for weed control in soybean RR® presents essential practical characteristics. However, although not allowed by the current Brazilian legislation, the association with other herbicides has been increasing for species of difficult control, as well as the use of tank

HUBBLE SPACE TELESCOPE PROPER MOTION (HSTPROMO) CATALOGS OF GALACTIC GLOBULAR CLUSTERS. I. SAMPLE SELECTION, DATA REDUCTION, AND NGC 7078 RESULTS

Energy Technology Data Exchange (ETDEWEB)

Bellini, A.; Anderson, J.; Van der Marel, R. P.; Watkins, L. L. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); King, I. R. [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); Bianchini, P. [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Chanamé, J. [Instituto de Astrofísica, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, Macul 782-0436, Santiago (Chile); Chandar, R. [Department of Physics and Astronomy, The University of Toledo, 2801 West Bancroft Street, Toledo, OH 43606 (United States); Cool, A. M. [Department of Physics and Astronomy, San Francisco State University, 1600 Holloway Avenue, San Francisco, CA 94132 (United States); Ferraro, F. R.; Massari, D. [Dipartimento di Fisica e Astronomia, Università di Bologna, via Ranzani 1, I-40127 Bologna (Italy); Ford, H., E-mail: bellini@stsci.edu [Department of Physics and Astronomy, The Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States)

2014-12-20

We present the first study of high-precision internal proper motions (PMs) in a large sample of globular clusters, based on Hubble Space Telescope (HST) data obtained over the past decade with the ACS/WFC, ACS/HRC, and WFC3/UVIS instruments. We determine PMs for over 1.3 million stars in the central regions of 22 clusters, with a median number of ∼60,000 stars per cluster. These PMs have the potential to significantly advance our understanding of the internal kinematics of globular clusters by extending past line-of-sight (LOS) velocity measurements to two- or three-dimensional velocities, lower stellar masses, and larger sample sizes. We describe the reduction pipeline that we developed to derive homogeneous PMs from the very heterogeneous archival data. We demonstrate the quality of the measurements through extensive Monte Carlo simulations. We also discuss the PM errors introduced by various systematic effects and the techniques that we have developed to correct or remove them to the extent possible. We provide in electronic form the catalog for NGC 7078 (M 15), which consists of 77,837 stars in the central 2.'4. We validate the catalog by comparison with existing PM measurements and LOS velocities and use it to study the dependence of the velocity dispersion on radius, stellar magnitude (or mass) along the main sequence, and direction in the plane of the sky (radial or tangential). Subsequent papers in this series will explore a range of applications in globular-cluster science and will also present the PM catalogs for the other sample clusters.

HST Proper Motions of Distant Globular Clusters: Constraining the Formation & Mass of the Milky Way

Science.gov (United States)

Sohn, S. Tony; van der Marel, Roeland P.; Deason, Alis; Bellini, Andrea; Besla, Gurtina; Watkins, Laura

2018-04-01

Proper motions (PMs) are required to calculate accurate orbits of globular clusters (GCs) in the Milky Way (MW) halo. We present our HST program to create a PM database for 20 GCs at distances of R GC = 10-100 kpc. Targets are discussed along with PM measurement methods. We also describe how our PM results can be used for Gaia as an external check, and discuss the synergy between HST and Gaia as astrometric instruments in the coming years.

An updated survey of globular clusters in M 31. III. A spectroscopic metallicity scale for the Revised Bologna Catalog

Science.gov (United States)

Galleti, S.; Bellazzini, M.; Buzzoni, A.; Federici, L.; Fusi Pecci, F.

2009-12-01

Aims. We present a new homogeneous set of metallicity estimates based on Lick indices for the old globular clusters of the M 31 galaxy. The final aim is to add homogeneous spectroscopic metallicities to as many entries as possible of the Revised Bologna Catalog of M 31 clusters, by reporting Lick index measurements from any source (literature, new observations, etc.) on the same scale. Methods: New empirical relations of [Fe/H] as a function of [MgFe] and Mg2 indices are based on the well-studied galactic globular clusters, complemented with theoretical model predictions for -0.2≤ [Fe/H]≤ +0.5. Lick indices for M 31 clusters from various literature sources (225 clusters) and from new observations by our team (71 clusters) have been transformed into the Trager et al. system, yielding new metallicity estimates for 245 globular clusters of M 31. Results: Our values are in good agreement with recent estimates based on detailed spectral fitting and with those obtained from color magnitude diagrams of clusters imaged with the Hubble Space Telescope. The typical uncertainty on individual estimates is ≃±0.25 dex, as resulted from the comparison with metallicities derived from color magnitude diagrams of individual clusters. Conclusions: The metallicity distribution of M 31 globular cluster is briefly discussed and compared with that of the Milky Way. Simple parametric statistical tests suggest that the distribution is probably not unimodal. The strong correlation between metallicity and kinematics found in previous studies is confirmed. The most metal-rich GCs tend to be packed into the center of the system and to cluster tightly around the galactic rotation curve defined by the HI disk, while the velocity dispersion about the curve increases with decreasing metallicity. However, also the clusters with [Fe/H]<-1.0 display a clear rotation pattern, at odds with their Milky Way counterparts. Based on observations made at La Palma, at the Spanish Observatorio del Roque

Efeitos de misturas de dinitramine e diuron em pré-plantio incorporado na cultura do algodão (Gossypium hirsutum L. Effects of dinitramine and diuron mixtures applied pre-planting incorporated on cotton (Gossypium hirsutum L.

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R. Victoria Filho

1982-06-01

Full Text Available Com o objetivo de se verificar o comportamento de misturas de dinitramine e diuron no controle de plantas daninhas na cultura do algodão, foram conduzidos dois experimentos de campo nos municípios paulistas de Casa Branca e Jaboticabal, em solo argiloso (3,6% m.o. e barrento (2,3% m.o., respectivamente. A variedade de algodão semeada foi a IAC -13-1 em Casa Branca (05-11-75 e a RM-4A em Jaboticabal (03-12-75. O delineamento experimental adotado foi o de blocos ao acaso com os tratamentos de dinitramine a 0,25 kg; 0,40 kg; 0,50 kg/ha; de diuron a 1,20 kg; 1,50 kg; 1,80 kg/ha, e das misturas de dinitramine e diuron nas combinações possíveis com essas doses além do tratamento de trifluralin a 1,00 kg/ha ou mistura com diuron a 1,20 kg/ha. Constou do experimento também um tratamento sem aplicação de herbicida, mantido no limpo por meios mecânicos. Quando foi considerado o controle geral das plantas daninhas, no ensaio de Casa Branca, os melhores resultados foramobtidos pelas misturas em comparação com as aplicações isoladas de dinitramine e de diuron sobre capim-colchão (Digitaria sanguinalis (L. Scop., capimpé-de-galinha (Eleusine indica (L. Gaertn., carrapicho-rasteiro (Acanthospermum australe (Loef O. Kúntze, poaia (Borreria alata (Aubl. D.C., poaia -branca (Richardia brasiliensis Gomez e guanxuma (Sida spp. Porém, no experimento de Jaboticabal, onde as plantas daninhas mais frequentes foram capim-colchão, capim-carrapicho (Cenchrus echinatus L., capim-oferecido (Pennisetum setosum L. Rich. Pers. carrapicho-rasteiro, poaia e guanxuma, os melhores índices de controle foram obtidos com trifluralin + diuron e com dinitramine a 0,25 kg; 0,40 kg; 0,50 kg/ha em mistura com diuron a 1,80 kg/ha. Não foram observados sintomas fitotóxicos à cultura na fase inicial de desenvolvimento; e, não houve diferença significativa na produção de algodão em caroço obtida.A field research was conducted to evaluate the effects of

Adição de inulina em géis de amido e leite utilizando planejamento experimental de misturas Addition of inulin to starch and milk gels using an experimental mixture design

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Luciana Pereira Lobato

2012-06-01

Full Text Available O objetivo deste estudo foi investigar o efeito combinado de inulina, amido e leite nas características texturais de géis e de propriedades de pastas empregando o planejamento experimental de misturas. Foram avaliados o perfil viscoamilográfico e a firmeza dos géis. Em todos os parâmetros avaliados, os modelos ajustados mostraram-se influenciados pela presença de inulina, amido e leite, assim como de algumas interações desses ingredientes. A viscosidade máxima e a viscosidade final foram influenciadas positivamente pela concentração de amido e negativamente pelas interações deste com leite e com inulina. A firmeza dos géis aumentou com o aumento do teor de amido, mas a interação amido-inulina foi antagônica, contribuindo para diminuir essa característica. O efeito da interação entre amido e inulina pode ser explicado pelo fato de que a inulina possui maior afinidade pela água, em relação ao amido, ou, ainda, por agir como diluente, fazendo com que haja menor contato entre os grânulos e/ou cadeias de amido. A partir dos resultados encontrados neste estudo, verifica-se que a inclusão da inulina em sistemas amido-leite pode influenciar nas características texturais e de viscosidade, possivelmente refletindo-se nas características sensoriais. Com isso, a avaliação das interações com outros ingredientes da formulação torna-se essencial.The objective of this work was to investigate the combined effect of milk, starch and inulin on the textural characteristics of gels and on the pasting properties, using an experimental mixture design. Gel firmness and the amylographic profile were evaluated. For all the parameters evaluated, the fitted models were shown to be influenced by the presence of inulin, starch and milk, as also some of the interactions between the ingredients. The maximum viscosity and final viscosity were positively influenced by the starch concentration and negatively by interactions between the starch and

GLOBULAR CLUSTER FORMATION EFFICIENCIES FROM BLACK HOLE X-RAY BINARY FEEDBACK

Energy Technology Data Exchange (ETDEWEB)

Justham, Stephen [The Key Laboratory of Optical Astronomy, National Astronomical Observatories, The Chinese Academy of Sciences, Datun Road, Beijing 100012 (China); Peng, Eric W. [Department of Astronomy, Peking University, Beijing 100871 (China); Schawinski, Kevin, E-mail: sjustham@nao.cas.cn [Institute for Astronomy, ETH Zurich, Wolfgang-Pauli-Strasse 27, 8093 Zurich (Switzerland)

2015-08-10

We investigate a scenario in which feedback from black hole X-ray binaries (BHXBs) sometimes begins inside young star clusters before strong supernova (SN) feedback. Those BHXBs could reduce the gas fraction inside embedded young clusters while maintaining virial equilibrium, which may help globular clusters (GCs) to stay bound when SN-driven gas ejection subsequently occurs. Adopting a simple toy model with parameters guided by BHXB population models, we produce GC formation efficiencies consistent with empirically inferred values. The metallicity dependence of BHXB formation could naturally explain why GC formation efficiency is higher at lower metallicity. For reasonable assumptions about that metallicity dependence, our toy model can produce a GC metallicity bimodality in some galaxies without a bimodality in the field-star metallicity distribution.

Standard globular cluster giant branches in the (MI/V-IO) plane

International Nuclear Information System (INIS)

Da Costa, G.S.; Armandroff, T.E.

1990-01-01

CCD photometry in the V, I (Cousins) bandpasses is presented for a large number of giants in eight galactic globular clusters. The (V-I) O color of the giant branch accurately ranks clusters in metal abundance, and can accordingly be used to ascertain both metal abundances and abundance dispersions in old stellar populations. A relation is derived that yields the bolometric correction to the I magnitude for red giants as a function of (V-I) O color. With this relation, and the assumption of the LDZ distance scale, the bolometric magnitudes of the brightest red giants in the clusters were determined; good agreement is obtained with the predictions of stellar evolution theory for the luminosity of the He core flash. 63 refs

Cúmulos globulares como trazadores de bimodalidad estelar en galaxias cD

Science.gov (United States)

Forte, J. C.

Se muestra que tanto la forma de los perfiles de brillo como de color observados en dos galaxias arquetípicas de tipo cD (NGC 1399 y NGC 4486) son compatibles con la presencia de poblaciones estelares bi-modales que comparten la misma distribución espacial y composición química de las familias dominantes de cúmulos globulares asociadas con ellas. El modelo resultante también predice una variación de la frecuencia específica de los cúmulos como función del radio galactocéntrico. Se discute este resultado en el contexto de una variedad de escenarios astrofísicos que intentan describir la formación de galaxias cD.

Chemical Abundances of Red Giant Stars in the Globular Cluster M107 (NGC 6171)

Science.gov (United States)

O'Connell, Julia E.; Johnson, Christian I.; Pilachowski, Catherine A.; Burks, Geoffrey

2011-10-01

We present chemical abundances of Al and several Fe-Peak and neutron-capture elements for 13 red giant branch stars in the Galactic globular cluster NGC 6171 (M107). The abundances were determined using equivalent width and spectrum synthesis analyses of moderate-resolution ( R ˜ 15,000), moderate signal-to-noise ratio ( ˜ 80) spectra obtained with the WIYN telescope and Hydra multifiber spectrograph. A comparison between photometric and spectroscopic effective temperature estimates seems to indicate that a reddening value of E(B - V) = 0.46 may be more appropriate for this cluster than the more commonly used value of E(B - V) = 0.33. Similarly, we found that a distance modulus of (m - M)V ≈ 13.7 provided reasonable surface gravity estimates for the stars in our sample. Our spectroscopic analysis finds M107 to be moderately metal-poor with = -0.93 and also exhibits a small star-to-star metallicity dispersion (σ = 0.04). These results are consistent with previous photometric and spectroscopic studies. Aluminum appears to be moderately enhanced in all program stars ( = +0.39, σ = 0.11). The relatively small star-to-star scatter in [Al/Fe] differs from the trend found in more metal-poor globular clusters, and is more similar to what is found in clusters with [Fe/H] ≳ -1. The cluster also appears to be moderately r-process-enriched with = +0.32 (σ = 0.17).

The direct piezoelectric effect in the globular protein lysozyme

Science.gov (United States)

Stapleton, A.; Noor, M. R.; Sweeney, J.; Casey, V.; Kholkin, A. L.; Silien, C.; Gandhi, A. A.; Soulimane, T.; Tofail, S. A. M.

2017-10-01

Here, we present experimental evidence of the direct piezoelectric effect in the globular protein, lysozyme. Piezoelectric materials are employed in many actuating and sensing applications because they can convert mechanical energy into electrical energy and vice versa. Although originally studied in inorganic materials, several biological materials including amino acids and bone, also exhibit piezoelectricity. The exact mechanisms supporting biological piezoelectricity are not known, nor is it known whether biological piezoelectricity conforms strictly to the criteria of classical piezoelectricity. The observation of piezoelectricity in protein crystals presented here links biological piezoelectricity with the classical theory of piezoelectricity. We quantify the direct piezoelectric effect in monoclinic and tetragonal aggregate films of lysozyme using conventional techniques based on the Berlincourt Method. The largest piezoelectric effect measured in a crystalline aggregate film of lysozyme was approximately 6.5 pC N-1. These findings raise fundamental questions as to the possible physiological significance of piezoelectricity in lysozyme and the potential for technical applications.

Aplicações de misturas solo-"grits" em estradas florestais: resistência mecânica via CBR Application of soil-grits mixtures in forest roads: mechanical strength via CBR test

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Reginaldo Sérgio Pereira

2006-08-01

Full Text Available Analisaram-se as potencialidades de emprego do resíduo sólido industrial "grits", oriundo da indústria de celulose, como agente estabilizante de dois solos da Zona da Mata Norte de Minas Gerais, Brasil, para fins de emprego em estradas florestais. Os solos estudados englobaram um residual maduro, de textura argilo-areno-siltosa, e um residual jovem, de textura areno-silto-argilosa. Para tanto, prepararam-se misturas envolvendo solos e o resíduo nos quantitativos de 4, 8, 12, 16, 20, 24 e 28% em relação às massas de solo seco. Fez-se uso do ensaio CBR para avaliar as características de resistência e expansão das misturas. A avaliação dos resultados do estudo permite concluir que o resíduo "grits" apresentou potencial significativo como estabilizante dos solos, observando-se que: (i a adição de "grits" aos solos foi responsável por ganhos nas suas resistências mecânicas, obtendo-se melhores resultados com o solo de textura areno-silto-argilosa; (ii com relação à expansão medida no ensaio CBR, observaram-se pequenos acréscimos para o solo de textura argilo-areno-siltosa e decréscimos para o solo de textura areno-silto-argilosa, com aumentos no teor de "grits"; e (iii as misturas solo-"grits" não responderam bem ao aumento da energia de compactação, quanto aos parâmetros CBR e expansãoCBR.This paper is directed to forest road engineering applications, and address the potentialities of using an industrial solid waste from the cellulose industry, named grits, in the stabilization process of two soils from Zona da Mata Norte of Minas Gerais States, Brazil. Soil types tested comprised a mature residual silty-sandy-clay and a young residual clayey-silty-sand. Soil-grits mixtures were prepared at 4, 8, 12, 16, 20, 24 and 28 % stabilizer contents referred to soil dry masses. Mechanical strength and swelling parameters were determined by CBR (California Bearing Ratio tests. The laboratory testing program data supported that

Influência da cera de carnaúba no comportamento reológico de misturas usadas na moldagem por injeção em baixa pressão

OpenAIRE

P. A. Ourique; R. C. D. Cruz; J. E. Zorzi

2015-01-01

A moldagem por injeção em baixa pressão (MIBP) tem algumas vantagens sobre outros métodos de conformação de peças cerâmicas com formas complexas. Dentre as vantagens estão os menores custos na produção de lotes pequenos e médios e o menor desgaste de moldes e equipamento. Neste trabalho, foi estudado o efeito de um dos aditivos orgânicos usados na MIBP, a cera de carnaúba, no comportamento reológico da mistura (feedstock). O pó cerâmico utilizado foi uma alumina, com tamanho de partícula em t...

AVALIAÇÃO MICROBIOLÓGICA DAS MISTURAS DE TEMPEROS PRONTOS PARA USO EM PRODUTOS DE CARNE

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Fernando Leite HOFFMANN

2009-07-01

Full Text Available

RESUMO: Foram realizadas análises microbiológicas, para determinar o número e os principais tipos ou grupos de microorganismos contidos em diferentes misturas de temperos prontos, para uso em produtos à base de carne (salsicha, lingüiça, mortadela e hambúrguer, através das seguintes determinações: enumeração de bactérias aeróbias mesófilas, enumeração de bolores e leveduras, determinação do número mais provável de coliformes totais e de coliformes fecais, pesquisa de Escherichia coli e pesquisa de Salmonella sp. Após a análise dos resultados obtidos e da comparação dos mesmos com a legislação em vigor, foi verificado que das doze amostras de condimentos analisadas, oito apresentaram contagens de bolores e leveduras acima do padrão estabelecido; sete estavam contaminadas por Salmonella; duas apresentaram coliformes façais; quatro apresentaram coliformes totais e em todas elas foi constatada a presença de bactérias aeróbias mesófilas. Das doze amostras analisadas, apenas duas estavam de acordo com os padrões vigentes, e poderiam ser utilizadas na elaboração de alimentos. PALAVRAS-CHAVE: Condimentos; avaliação microbiológica.

Sistemas microfluídicos amperométricos utilizando enzimas imobilizadas

OpenAIRE

Luís Marcos Cerdeira Ferreira

2011-01-01

Este trabalho descreve o desenvolvimento de um sistema microfluídico, contendo, como componente principal, um reator enzimático constituído de um microcanal fabricado em substrato de poli(metacrilato de metila) e um sistema amperométrico como detector. Para a construção de microcanais foi utilizando equipamento de usinagem a laser de CO2 para escavar os microcanais, que a seguir foram selados termicamente. A superfície interna desse microcanal foi submetida à modificação química com poli(etil...

On the radial distribution of white dwarfs in the Galactic globular cluster omega Cen

Science.gov (United States)

Calamida, A.; Corsi, C. E.; Bono, G.; Stetson, P. B.; Prada Moroni, P. G.; Degl'Innocenti, S.; Ferraro, I.; Iannicola, G.; Koester, D.; Pulone, L.; Monelli, M.; Amico, P.; Buonanno, R.; Freyhammer, L. M.; Marchetti, E.; Nonino, M.; Romaniello, M.

We present deep and accurate photometry (F435W, F625W, F658N) of the Galactic Globular Cluster omega Cen collected with the Advanced Camera for Surveys (ACS) on board the Hubble Space Telescope (HST). We identified ≈ 6,500 white dwarf (WD) candidates and compared their radial distribution with that of Main Sequence (MS) stars. We found a mild evidence that young WDs ( 0.1 ≲ t ≲ 0.6 Gyr) are less centrally concentrated when compared to MS stars in the magnitude range 25 < F435W < 26.5.

ALMA reveals sunburn: CO dissociation around AGB stars in the globular cluster 47 Tucanae

OpenAIRE

McDonald, Iain; Zijlstra, Albert A.; Lagadec, Eric; Sloan, Gregory C.; Boyer, Martha L.; Matsuura, Mikako; Smith, Rowan J.; Smith, Christina L.; Yates, Jeremy A.; van Loon, Jacco Th.; Jones, Olivia C.; Ramstedt, Sofia; Avison, Adam; Justtanont, Kay; Olofsson, Hans

2015-01-01

Atacama Large Millimetre Array observations show a non-detection of carbon monoxide around the four most luminous asymptotic giant branch (AGB) stars in the globular cluster 47 Tucanae. Stellar evolution models and star counts show that the mass-loss rates from these stars should be similar to 1.2-3.5x10(-7) M-circle dot yr(-1). We would naively expect such stars to be detectable at this distance (4.5 kpc). By modelling the ultraviolet radiation field from post-AGB stars and white dwarfs in 4...

Avaliação das propriedades de misturas de poliestireno com oligômeros de poli(Óxido de Propileno e poliestireno Property relationships in blends based on polystyrene

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Maria Andréa P. R. Torres

1998-01-01

Full Text Available Misturas poliméricas de poliestireno (PS1 com poli(óxido de propileno (PPO e de poliestireno (PS1 com poliestireno de baixíssima massa molecular (PS2, foram preparadas, em diversas composições, para avaliação das propriedades térmicas, mecânicas e de escoamento. As propriedades térmicas foram avaliadas por calorimetria diferencial de varredura (DSC e as propriedades mecânicas e de escoamento foram determinadas através de ensaios de tração e monitoração do valor do torque durante o processamento das misturas, respectivamente. Foi observado que o PPO atua como plastificante do poliestireno enquanto que o PS2 não apresenta este comportamento. Entretanto, a adição de ambos os componentes produz mudança no empacotamento molecular, originando o aparecimento de fissuras na superfície dos materiais.Poly(propylene oxide (PPO and polystyrene of lower molecular weight were added to commercial polystyrene. These blends were prepared in a Haake internal mixer and the properties of polystyrene/poly(propylene oxide and polystyrene/polystyrene of lower molecular weight blends were evaluated using tensile testing, differential scanning calorimetry and torque curves obtained during the process. The results obtained show that PPO acts as a plasticizer for polystyrene, decreasing significantly its torque value and the glass transition temperature. The addition of polystyrene of lower molecular weight to polystyrene causes subtle modifications. However, the addition of both PPO and polystyrene of lower molecular weight to polystyrene probably accelerates crazes formation and it is usually detrimental to the mechanical properties.

REFRIGERAÇÃO UTILIZANDO PASTILHAS DE EFEITO PELTIER

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Antonio Luiz P. S. Campos

2010-06-01

Full Text Available Pastilhas de Peltier são dispositivos baseados no efeito Peltier e são aplicadas para produzir efeito refrigerador ou aquecedor. Este trabalho aborda conceitos envolvidos na fabricação e funcionamento desses dispositivos tais como: histórico do efeito Peltier e desenvolvimento de placas de efeito Peltier. É feito um estudo de eficiência da refrigeração de água utilizando uma placa de efeito Peltier existente no Campus Natal – Zona Norte. Para isso, é implementada uma estrutura de refrigeração de água e são feitas medições para determinar a eficiência de sistema. Por fim, são apresentadas conclusões sobre o estudo desenvolvido.

The accretion-heated crust of the transiently accreting 11-Hz X-ray pulsar in the globular cluster Terzan 5

NARCIS (Netherlands)

Degenaar, N.; Wijnands, R.

2011-01-01

We report on a Chandra Director’s Discretionary Time observation of the globular cluster Terzan 5, carried out ∼7 weeks after the cessation of the 2010 outburst of the newly discovered transiently accreting 11-Hz X-ray pulsar. We detect a thermal spectrum that can be fitted with a neutron star

Leaching of hexazinone and mixture hexazinone + diuron in columns of soils with distinct textures. = Lixiviação do hexazinone e da mistura hexazinone + diuron em colunas de solos com texturas distintas.

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Kassio Ferreira Mendes

2013-08-01

Full Text Available Objective to evaluate the leaching of the hexazinone and admixed with diuron, in soil of contrasting textures, in soil columns under different rainfall. The following soils were used: Red Latosol - LV, of clay texture and Quartzarenic Neosol - NQ, sandy texture. The experimental units were constituted by PVC columns filled with soil, at rates of hexazinone (LV - 375 g ha -1 and NQ - 225 g ha -1 and hexazinone + diuron (LV - 396 + 1,404 g ha -1 and NQ - 264 + 936 g ha-1 . The factorial 6 x 6 in randomized block design, with three replications was adopted. Factor A evaluated the precipitation of 0, 20, 40, 60, 80, and 100 mm; factor B analyzed the depths (0-5, 5-10, 10-15, 15-20, 20-25 and 25-30 cm column. Posteriorly the rain simulation the columns were longitudinally opened and along these were sown Cucumis sativus. Independent of soil texture, the hexazinoneand mixture hexazinone + diuron did not exceed 10-15 cm layer of soil, the layer of 0 mm. The hexazinone and diuron + hexazinone mixture showed phytotoxicity of species bioindicator in the layer of 20-25 cm in LV, and reaching up to 25-30 cm in NQ, the greatest layer simulated. It was concluded that there was no difference in leaching potential of hexazinone when mixture with diuron in soils with distinct textures, however the clay textural composition, organic matter content of soil and rainfall influenced the leaching. = Objetivou-se avaliar a lixiviação do hexazinone isoladamente e da mistura com o diuron, em solos de texturas contrastantes, em colunas de solos sob diferentes precipitações. Utilizou-se um Latossolo Vermelho – LV, de textura argilosa e um Neossolo Quartzarênico – NQ, de textura arenosa. As unidades experimentais foram constituídas por colunas de PVC preenchidas com solos, nas doses de hexazinone (LV - 375 g ha -1 e NQ - 225 g ha -1 e hexazinone + diuron (LV - 396 + 1.404 g ha -1 e NQ - 264 + 936 g ha -1 . Adotou-se o esquema fatorial 6 x 6 no delineamento em

Nuevo criterio de complejidad utilizando una medida de eficiencia

OpenAIRE

Munduate del Río, Arantza; Pérez Prados, Antonio; Cano Sevilla, Francisco J.

1995-01-01

Centrado en el campo de los árboles de decisión, este trabajo estudia la forma de selección de un árbol óptimo entre los posibles árbo1es obtenidos a partir del análisis de un conjunto de datos, utilizando para ello una cantidad criterio que combina linealmente dos medidas de la calidad de un árbol: el error de resustitución y la eficiencia. Analizando el efecto de un proceso de poda en la cantidad criterio se obtiene una sucesión finita de subárboles rnínimos óptimamente podados del árbol má...

Central Rotations of Milky Way Globular Clusters

Science.gov (United States)

Fabricius, Maximilian H.; Noyola, Eva; Rukdee, Surangkhana; Saglia, Roberto P.; Bender, Ralf; Hopp, Ulrich; Thomas, Jens; Opitsch, Michael; Williams, Michael J.

2014-06-01

Most Milky Way globular clusters (GCs) exhibit measurable flattening, even if on a very low level. Both cluster rotation and tidal fields are thought to cause this flattening. Nevertheless, rotation has only been confirmed in a handful of GCs, based mostly on individual radial velocities at large radii. We are conducting a survey of the central kinematics of Galactic GCs using the new Integral Field Unit instrument VIRUS-W. We detect rotation in all 11 GCs that we have observed so far, rendering it likely that a large majority of the Milky Way GCs rotate. We use published catalogs of GCs to derive central ellipticities and position angles. We show that in all cases where the central ellipticity permits an accurate measurement of the position angle, those angles are in excellent agreement with the kinematic position angles that we derive from the VIRUS-W velocity fields. We find an unexpected tight correlation between central rotation and outer ellipticity, indicating that rotation drives flattening for the objects in our sample. We also find a tight correlation between central rotation and published values for the central velocity dispersion, most likely due to rotation impacting the old dispersion measurements. This Letter includes data taken at The McDonald Observatory of The University of Texas at Austin.

Proteolytic activities of kiwifruit actinidin (Actinidia deliciosa cv. Hayward) on different fibrous and globular proteins: a comparative study of actinidin with papain.

Science.gov (United States)

Chalabi, Maryam; Khademi, Fatemeh; Yarani, Reza; Mostafaie, Ali

2014-04-01

Actinidin, a member of the papain-like family of cysteine proteases, is abundant in kiwifruit. To date, a few studies have been provided to investigate the proteolytic activity and substrate specificity of actinidin on native proteins. Herein, the proteolytic activity of actinidin was compared to papain on several different fibrous and globular proteins under neutral, acidic and basic conditions. The digested samples were subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and densitometry to assess the proteolytic effect. Furthermore, the levels of free amino nitrogen (FAN) of the treated samples were determined using the ninhydrin colorimetric method. The findings showed that actinidin has no or limited proteolytic effect on globular proteins such as immunoglobulins including sheep IgG, rabbit IgG, chicken IgY and fish IgM, bovine serum albumin (BSA), lipid transfer protein (LTP), and whey proteins (α-lactalbumin and β-lactoglobulin) compared to papain. In contrast to globular proteins, actinidin could hydrolyze collagen and fibrinogen perfectly at neutral and mild basic pHs. Moreover, this enzyme could digest pure α-casein and major subunits of micellar casein especially in acidic pHs. Taken together, the data indicated that actinidin has narrow substrate specificity with the highest enzymatic activity for the collagen and fibrinogen substrates. The results describe the actinidin as a mild plant protease useful for many special applications such as cell isolation from different tissues and some food industries as a mixture formula with other relevant proteases.

Direcionadores de preferencia para nectares de uva comerciais tradicionais e "lights" utilizando regressão por minimos quadrados parciais (PLSR).

OpenAIRE

Leonardo Rangel Alves

2008-01-01

Resumo: Este estudo objetivou Identificar direcionadores de preferência de oito amostras comerciais de néctar de uva (tradicionais e "light") utilizando metodologias estatísticas avançadas para relacionar dados de perfil sensorial, físico-químicos e aceitabilidade. Oito amostras comerciais de néctares de uva (quatro tradicionais e suas respectivas versões "light") foram analisadas. Um teste de Aceitação utilizando a escala hedônica híbrida foi realizado com 114 consumidores. Quatorze termos d...

Uso do resíduo industrial grits em pavimentos de estradas florestais: influência do período de cura na resistência mecânica e expansão de misturas solo-grits compactadas Use of industrial grits in forest road pavements: influence of curing times on the mechanical strength and swelling of compacted soil-grits mixtures

Directory of Open Access Journals (Sweden)

Reginaldo Sérgio Pereira

2006-10-01

Full Text Available Analisou-se a influência do teor de estabilizante, da energia de compactação e do período de cura na resistência mecânica e expansão de dois solos da Zona da Mata Norte de Minas Gerais. As amostras de solos residuais de gnaisse coletadas na cidade de Viçosa, MG, Brasil, respectivamente, de texturas argilo-areno-siltosa e areno-argilo-siltosa, foram denominadas solos 1 e 2. Empregou-se como estabilizante químico o resíduo "grits" fornecido pela empresa de Celulose Nipo Brasileira (CENIBRA; os teores, em massa, de 4, 8, 12, 16, 20, 24 e 28% desse resíduo foram utilizados nas misturas solo-"grits". Corpos-de-prova das misturas solo-"grits" foram compactados nos teores ótimos de umidade relativos às energias de compactação dos ensaios Proctor intermediário e modificado e curados por 0, 7, 28 e 90 dias. Avaliou-se a resistência mecânica dos solos e misturas através dos seguintes parâmetros: (a índice de suporte Califórnia (ISC ou CBR, resistência à compressão não confinada (RCNC e resistência à tração em compressão diametral (Rt. Os resultados permitiram concluir que todos os parâmetros considerados na análise influenciaram, significativamente, a resistência mecânica das misturas solo-"grits", sendo o comportamento das misturas solo 1-"grits" influenciado, também, pelo teor de sódio presente na constituição química do "grits".This paper addresses the influence of stabilizer content, compaction effort and curing time on the mechanical strength and swelling of two soils from the "Zona da Mata Norte" region, State of Minas Gerais, Brazil. Two residual gneiss soils from the municipality of Viçosa, Brazil, silt-sand-clay and silt-clay-sandy soils named soils 1 and 2, respectively, were used in this study. Industrial grits provided by Celulose Nipo Brasileira - CENIBRA was used as stabilizer, with contents ranging from 4 to 28 % regarding soil dry mass. Specimens of soil-grits mixtures were compacted at the

Propriedades físicas de misturas para sherbet de mangaba Physical properties of mixes to mangaba sherbet

Directory of Open Access Journals (Sweden)

Alessandra Lopes de Oliveira

2005-06-01

Full Text Available O objetivo deste trabalho foi avaliar a viscosidade, a quantidade de água não congelada (w nc e a temperatura de transição vítrea da fração maximamente crioconcentrada (Tg' de misturas para sherbet, e a incorporação de ar (IAr dos sherbets, com diferentes concentrações de goma guar (0,2% a 0,5% e polpa de mangaba (21,1%, 25,8% e 28,6%. A viscosidade aparente variou de 85,8 a 286,1 cP, aumentando com as concentrações de goma guar e mangaba. As análises térmicas com calorímetro diferencial de varredura mostraram que a w nc variou entre 12% e 20%, diminuindo com o aumento da concentração de polpa. A Tg' variou de -57,65ºC a -53,45ºC e não apresentou diferença entre as amostras. A IAr foi de 20,01% a 40,59%. Sherbets com a mesma concentração de polpa apresentaram valores diferentes desta variável, mas uma relação entre o aumento da quantidade de goma guar e maior IAr foi observada somente para os sherbets com 25,8% de polpa. O estabilizante interfere na viscosidade da mistura e IAr, e a concentração de polpa influencia as propriedades térmicas. O aumento de IAr proporciona melhor maciez ao produto. Maior quantidade de polpa diminui a w nc, assim o produto terá menos água disponível para migrar e formar cristais de gelo maiores durante as oscilações na temperatura, diminuindo a qualidade do produto.Viscosity, unfrozen water (w nc and glass transition temperature of the maximally freeze-concentrated material (Tg' of sherbet mixtures and the overrum of the sherbets with different concentrations of guar gum (from 0.2% to 0.5% and mangaba pulp (21.1%, 25.8% and 28.5% were evaluated. Apparent viscosity ranged from 85.8 to 286.1 cP, increasing with guar gum concentration and mangaba pulp. Thermal analysis using differential scanning calorimetry of sherbets mixture showed that w nc was from 12% to 20%, decreasing with the increasing of mangaba pulp concentration. The Tg' ranged from -57.65ºC to -53.45ºC and was not

Degradação de poliolefinas utilizando catalisadores zeolíticos

OpenAIRE

Valle,Maria Letícia M.; Guimarães,Maria José O. C.; Sampaio,Cristiane M. S.

2004-01-01

Neste trabalho foi estudada a degradação de alguns dos principais constituintes dos rejeitos plásticos (polietileno de alta densidade (HDPE), polietileno de baixa densidade (LDPE) e polipropileno (PP)), empregando-se um catalisador exausto de unidades de craqueamento de fluidos (FCC) e um catalisador zeolítico (ADZ3) sintetizado em laboratório. Utilizando técnicas de termogravimetria (TG-DTG) e cromatografia gasosa (CG), foi possível avaliar os produtos gerados no craqueamento destas poliolef...

ON THE RR LYRAE STARS IN GLOBULARS. IV. ω CENTAURI OPTICAL UBVRI PHOTOMETRY

Energy Technology Data Exchange (ETDEWEB)

Braga, V. F.; Bono, G.; Buonanno, R. [Department of Physics, Università di Roma Tor Vergata, via della Ricerca Scientifica 1, I-00133 Roma (Italy); Stetson, P. B. [NRC-Herzberg, Dominion Astrophysical Observatory, 5071 West Saanich Road, Victoria BC V9E 2E7 (Canada); Dall’Ora, M. [INAF-Osservatorio Astronomico di Capodimonte, Salita Moiariello 16, I-80131 Napoli (Italy); Ferraro, I.; Iannicola, G.; Castellani, M. [INAF-Osservatorio Astronomico di Roma, via Frascati 33, I-00040 Monte Porzio Catone (Italy); Fiorentino, G. [INAF-Osservatorio Astronomico di Bologna, Via Ranzani 1, I-40127 Bologna (Italy); Freyhammer, L. M. [Jeremiah Horrocks Institute of Astrophysics, University of Central Lancashire, Preston PR1 2HE (United Kingdom); Marengo, M.; Neeley, J. [Department of Physics and Astronomy, Iowa State University, Ames, IA 50011 (United States); Valenti, E. [European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching bei Munchen (Germany); Calamida, A. [National Optical Astronomy Observatory, 950 N Cherry Avenue, Tucson, AZ 85719 (United States); Da Silva, R.; Fabrizio, M.; Giuffrida, G. [ASDC, via del Politecnico snc, I-00133 Roma (Italy); Degl’Innocenti, S. [INFN, Sezione di Pisa, Largo Pontecorvo 3, I-56127, Pisa (Italy); Di Cecco, A. [INAF-Osservatorio Astronomico di Teramo, Via Mentore Maggini snc, Loc. Collurania, I-64100 Teramo (Italy); Freedman, W. L. [Department of Astronomy and Astrophysics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); and others

2016-12-01

New accurate and homogeneous optical UBVRI photometry has been obtained for variable stars in the Galactic globular cluster ω Cen (NGC 5139). We secured 8202 CCD images covering a time interval of 24 years and a sky area of 84 × 48 arcmin. The current data were complemented with data available in the literature and provided new, homogeneous pulsation parameters (mean magnitudes, luminosity amplitudes, periods) for 187 candidate ω Cen RR Lyrae (RRLs). Among them we have 101 RRc (first overtone) and 85 RRab (fundamental) variables, and a single candidate RRd (double-mode) variable. Candidate Blazhko RRLs show periods and colors that are intermediate between the RRc and RRab variables, suggesting that they are transitional objects. A comparison of the period distribution and the Bailey diagram indicates that RRLs in ω Cen show a long-period tail not present in typical Oosterhoff II (OoII) globulars. The RRLs in dwarf spheroidals and in ultra-faint dwarfs have properties between Oosterhoff intermediate and OoII clusters. Metallicity plays a key role in shaping the above evidence. These findings do not support the hypothesis that ω Cen is the core remnant of a spoiled dwarf galaxy. Using optical period–Wesenheit relations that are reddening-free and minimally dependent on metallicity we find a mean distance to ω Cen of 13.71 ± 0.08 ± 0.01 mag (semi-empirical and theoretical calibrations). Finally, we invert the I -band period–luminosity–metallicity relation to estimate individual RRLs’ metal abundances. The metallicity distribution agrees quite well with spectroscopic and photometric metallicity estimates available in the literature.

An Extremely Lithium-rich Bright Red Giant in the Globular Cluster M3

Science.gov (United States)

Kraft, Robert P.; Peterson, Ruth C.; Guhathakurta, Puragra; Sneden, Christopher; Fulbright, Jon P.; Langer, G. Edward

1999-06-01

We have serendipitously discovered an extremely lithium-rich star on the red giant branch of the globular cluster M3 (NGC 5272). An echelle spectrum obtained with the Keck I High-Resolution Echelle Spectrograph reveals a Li I λ6707 resonance doublet of 520 mÅ equivalent width, and our analysis places the star among the most Li-rich giants known: logε(Li)~=+3.0. We determine the elemental abundances of this star, IV-101, and three other cluster members of similar luminosity and color and conclude that IV-101 has abundance ratios typical of giants in M3 and M13 that have undergone significant mixing. We discuss mechanisms by which a low-mass star may be so enriched in Li, focusing on the mixing of material processed by the hydrogen-burning shell just below the convective envelope. While such enrichment could conceivably happen only rarely, it may in fact regularly occur during giant-branch evolution but be rarely detected because of rapid subsequent Li depletion. Based on observations obtained with the Keck I Telescope of the W. M. Keck Observatory, which is operated by the California Association for Research in Astronomy (CARA), Inc., on behalf of the University of California and the California Institute of Technology. This Letter is dedicated to the memory of our beloved colleague Ed Langer, who died after a brief illness on February 16, 1999. Ed brought a unique theoretical perspective to our globular cluster abundance studies. His career truly embodied the academic ideals of inspiration in both teaching and research. He made friends wherever he traveled, and was an inspiration to students. We will miss him greatly.

Therapeutic effects of globular adiponectin in diabetic rats with nonalcoholic fatty liver disease.

Science.gov (United States)

Ma, Hong; Cui, Fan; Dong, Jing-Jing; You, Guo-Ping; Yang, Xiang-Jiu; Lu, Hua-Dong; Huang, Yan-Ling

2014-10-28

To explore the therapeutic role of globular adiponectin (gAd) in high-fat diet/streptozotocin (STZ)-induced type 2 diabetic rats with nonalcoholic fatty liver disease (NAFLD). Seven rats were fed a basic diet (normal control group; NC) during the experiment. Experimental rats (14 rats) were given a high-fat diet for 4 wk and were then injected with STZ to induce type 2 diabetes mellitus (T2DM) and NAFLD. Half of the T2DM/NAFLD rats were randomly injected intraperitoneally with gAd for 7 d (gAd-treated group), while the other 7 rats (T2DM/NAFLD group) received 0.9% saline. Plasma biochemical parameters and insulin concentrations were measured. Liver histopathology was examined by hematoxylin-eosin staining. Insulin receptor expression in the liver was analyzed by immunohistochemical staining, Western blot and quantitative real-time reverse transcription polymerase chain reaction analysis. Compared to the control group, the T2DM/NAFLD group had increased levels of glucolipid and decreased levels of insulin. Plasma glucose and lipid levels were decreased in the gAd-treated group, while serum insulin levels increased. The expression of insulin receptor in the T2DM/NAFLD group increased compared with the NC group, and gAd downregulated insulin receptor expression in the livers of T2DM/NAFLD rats. Steatosis of the liver was alleviated in the gAd-treated group compared to the T2DM/NAFLD group (NAS 1.39 ± 0.51 vs 1.92 ± 0.51, P Globular adiponectin exerts beneficial effects in T2DM rats with NAFLD by promoting insulin secretion, mediating glucolipid metabolism, regulating insulin receptor expression and alleviating hepatic steatosis.

Co-evolutionary constraints of globular proteins correlate with their folding rates.

Science.gov (United States)

Mallik, Saurav; Kundu, Sudip

2015-08-04

Folding rates (lnkf) of globular proteins correlate with their biophysical properties, but relationship between lnkf and patterns of sequence evolution remains elusive. We introduce 'relative co-evolution order' (rCEO) as length-normalized average primary chain separation of co-evolving pairs (CEPs), which negatively correlates with lnkf. In addition to pairs in native 3D contact, indirectly connected and structurally remote CEPs probably also play critical roles in protein folding. Correlation between rCEO and lnkf is stronger in multi-state proteins than two-state proteins, contrasting the case of contact order (co), where stronger correlation is found in two-state proteins. Finally, rCEO, co and lnkf are fitted into a 3D linear correlation. Copyright © 2015 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Omnipresence of the polyproline II helix in fibrous and globular proteins.

Science.gov (United States)

Esipova, Natalia G; Tumanyan, Vladimir G

2017-02-01

Left-handed helical conformation of a polypeptide chain (PPII) is the third type of the protein backbone structure. This conformation universally exists in fibrous, globular proteins, and biologically active peptides. It has unique physical and chemical properties determining a wide range of biological functions, from the protein folding to the tissue differentiation. New examples of the structure have been appearing in spite of difficulties in their detection and investigation. The annotation and prediction of the PPII was also a challenging task. Recently, many PPII motifs with new and/or unexpected functions are being accumulated in databases. In this review we describe the major structural and dynamic forms of PPII, the diversity of its functions, and the role in different biological processes. Copyright © 2016 Elsevier Ltd. All rights reserved.

Globular adiponectin controls insulin-mediated vasoreactivity in muscle through AMPKα2

DEFF Research Database (Denmark)

de Boer, Michiel P; Meijer, Rick I; Richter, Erik

2016-01-01

Decreased tissue perfusion increases the risk of developing insulin resistance and cardiovascular disease in obesity, and decreased levels of globular adiponectin (gAdn) have been proposed to contribute to this risk. We hypothesized that gAdn controls insulin's vasoactive effects through AMP......-activated protein kinase (AMPK), specifically its α2 subunit, and studied the mechanisms involved. In healthy volunteers, we found that decreased plasma gAdn levels in obese subjects associate with insulin resistance and reduced capillary perfusion during hyperinsulinemia. In cultured human microvascular...... endothelial cells (HMEC), gAdn increased AMPK activity. In isolated muscle resistance arteries gAdn uncovered insulin-induced vasodilation by selectively inhibiting insulin-induced activation of ERK1/2, and the AMPK inhibitor compound C as well as genetic deletion of AMPKα2 blunted insulin...

VizieR Online Data Catalog: NGC3115 & NGC1399 VEGAS-SSS globular clusters (Cantiello+, 2018)

Science.gov (United States)

Cantiello, M.; D'Abrusco, R.; Spavone, M.; Paolillo, M.; Capaccioli, M.; Limatola, L.; Grado, A.; Iodice, E.; Raimondo, G.; Napolitano, N.; Blakeslee, J. P.; Brocato, E.; Forbes, D. A.; Hilker, M.; Mieske, S.; Peletier, R.; van de Ven, G.; Schipani, P.

2017-11-01

Photometric catalogs for globular cluster (GC) candidates over the the 1 sq. degree area around NGC3115 and NGC1399 (ngc3115.dat and ngc1399.dat). The catalogues are based on u-, g- and i- band images from the VST elliptical galaxies survey (VEGAS). Aperture magnitudes, corrected for aperture correction are reported. We also provide the full catalogs of matched sources, which also include the matched background and foreground sources in the frames (ngc3115_full.dat and ngc1399_full.dat). (4 data files).

FRACIONAMENTO DE ÓLEOS DE CITROS UTILIZANDO FLUIDOS SUPERCRÍTICOS

Directory of Open Access Journals (Sweden)

Marisa MENDES

1997-12-01

Full Text Available O objetivo deste trabalho é o estudo sobre o fracionamento do óleo de laranja. Neste sentido, o limoneno e o linalol foram considerados os componentes-chaves do óleo de laranja, representando os terpenos e compostos oxigenados, respectivamente. Para modelar os dados de equilíbrio de fases foi usada a equação de estado de Peng-Robinson, juntamente com as regras de mistura de van der Waals, uni e biparamétrica, e de Panagiotopoulos e Reid. O uso desses modelos termodinâmicos permitiu determinar as condições de temperatura e pressão que levaram aos melhores valores do par seletividade-capacidade.The objective of this work is to study the fractionation of the citrus oils, especially orange oil. The orange oil is considered to be a mixture of two main components, limonene and linalool, which represent the terpenes and oxygenated group fractions, respectively. The Peng-Robinson equation of state using the van der Waals, with one or two parameters, and Panagiotopoulos and Reid mixing rules, were used to correlate and predict the binary and ternary high pressure phase equilibria of CO2 containing systems . The use of thermodynamic models to predict the phase equilibria allowed to establish the conditions of temperature and pressure, which led to the best results of selectivities and capacities of the extraction.

Chemical abundances of globular clusters in NGC 5128 (Centaurus A)

Science.gov (United States)

Hernandez, Svea; Larsen, Søren; Trager, Scott; Kaper, Lex; Groot, Paul

2018-06-01

We perform a detailed abundance analysis on integrated-light spectra of 20 globular clusters (GCs) in the early-type galaxy NGC 5128 (Centaurus A). The GCs were observed with X-Shooter on the Very Large Telescope (VLT). The cluster sample spans a metallicity range of -1.92 poor GCs in NGC 5128 is genuine, it could hint at a chemical enrichment history different than that experienced by the MW. We also measure Na abundances in 9 out of 20 GCs. We find evidence for intracluster abundance variations in six of these clusters where we see enhanced [Na/Fe] > +0.25 dex. We obtain the first abundance measurements of Cr, Mn, and Ni for a sample of the GC population in NGC 5128 and find consistency with the overall trends observed in the MW, with a slight enhancement (<0.1 dex) in the Fe-peak abundances measured in the NGC 5128.

Changes in physical properties of extruded sour cassava starch and quinoa flour blend snacks Mudanças nas propriedades físicas de snacks extrusados de misturas de polvilho azedo e farinha de quinoa

Directory of Open Access Journals (Sweden)

Lívia Giolo Taverna

2012-12-01

Full Text Available Given the broad acceptance of sour cassava starch biscuits in Brazil and the nutritional quality of quinoa flour, this study aimed to evaluate the effect of extrusion temperature, screw speed, moisture, and amount of quinoa flour on the physical properties of puffed snacks. Extrusion process was carried out using a single-screw extruder in a factorial central composite design with four factors. Effects of moisture and amount of quinoa flour on the expansion index and specific volume of snacks were observed. There was a pronounced increase in water solubility index of blends with the extrusion process with significant effects of all process parameters on the WSI. Higher water absorption index (WAI was observed under high temperature, low moisture, and lower quinoa flour amount. Temperature and amount of quinoa flour influenced the color of the snacks. A positive quadratic effect of quinoa flour on hardness of products was observed. Blends of sour cassava starch and quinoa flour have good potential for use as raw material in production of extruded snacks with good physical properties.Dada a ampla aceitação do biscoito de polvilho azedo no Brasil e a qualidade nutricional da farinha de quinoa, este trabalho objetivou avaliar o efeito da temperatura de extrusão, rotação da rosca, umidade e porcentagem de farinha de quinoa sobre as propriedades físicas de snacks expandidos. O processo foi realizado em extrusor monorrosca, seguindo o delineamento central composto rotacional para quatro fatores. Foi observado o efeito da umidade e da porcentagem de farinha de quinoa sobre o índice de expansão e volume específico. Houve um aumento pronunciado na solubilidade das misturas com o processo de extrusão, com efeitos significativos de todos os parâmetros de processo no ISA. Maior índice de absorção de água (IAA foi observado em alta temperatura, baixa umidade e menor porcentagem de farinha de quinoa. Temperatura e porcentagem de farinha de

An intermediate-mass black hole in the centre of the globular cluster 47 Tucanae.

Science.gov (United States)

Kızıltan, Bülent; Baumgardt, Holger; Loeb, Abraham

2017-02-08

Intermediate-mass black holes should help us to understand the evolutionary connection between stellar-mass and super-massive black holes. However, the existence of intermediate-mass black holes is still uncertain, and their formation process is therefore unknown. It has long been suspected that black holes with masses 100 to 10,000 times that of the Sun should form and reside in dense stellar systems. Therefore, dedicated observational campaigns have targeted globular clusters for many decades, searching for signatures of these elusive objects. All candidate signatures appear radio-dim and do not have the X-ray to radio flux ratios required for accreting black holes. Based on the lack of an electromagnetic counterpart, upper limits of 2,060 and 470 solar masses have been placed on the mass of a putative black hole in 47 Tucanae (NGC 104) from radio and X-ray observations, respectively. Here we show there is evidence for a central black hole in 47 Tucanae with a mass of solar masses when the dynamical state of the globular cluster is probed with pulsars. The existence of an intermediate-mass black hole in the centre of one of the densest clusters with no detectable electromagnetic counterpart suggests that the black hole is not accreting at a sufficient rate to make it electromagnetically bright and therefore, contrary to expectations, is gas-starved. This intermediate-mass black hole might be a member of an electromagnetically invisible population of black holes that grow into supermassive black holes in galaxies.

Uso de resíduos em pavimentos de estradas florestais: caracterização de solos e misturas solo-grits Application of waste in forest road pavements: characterization of soils and soil-grits mixtures

Directory of Open Access Journals (Sweden)

Reginaldo Sérgio Pereira

2006-08-01

Full Text Available Este artigo aborda uma etapa preliminar de um estudo direcionado às propriedades de engenharia de misturas de solos e aditivos químicos, para fins de aplicação em estradas florestais. Trabalhou-se com amostras de dois solos da Zona da Mata Norte de Minas Gerais, Brasil, de texturas arenosa e argilosa, estabilizadas com o resíduo industrial denominado "grits" proveniente de indústria de celulose. Foram realizados ensaios geotécnicos nos solos e nas misturas solo-aditivo químico, como se segue: análise granulométrica, peso específico dos sólidos, limites de Atterberg e compactação. Os resultados encontrados dos ensaios de laboratório revelaram que o resíduo apresentou bom desempenho como agente estabilizante, alterando significativamente a plasticidade e os parâmetros de compactação dos solos analisados.This paper addresses data from a research program in development on engineering properties of soil-chemical stabilizer mixtures for forest road application. Soil samples from sandy and clayey soils from the Zona da Mata Norte of Minas Gerais, Brazil, stabilized with grits (waste from cellulose industries were used throughout the study. The laboratory-testing program comprised the following geotechnical tests: sieve analysis, density of solid particles, Atterberg limits and compaction. Data supported the good behavior of waste as stabilizer agent changing significantly soil plasticity and compaction parameters.

Strong Keratin-like Nanofibers Made of Globular Protein

Science.gov (United States)

Dror, Yael; Makarov, Vadim; Admon, Arie; Zussman, Eyal

2008-03-01

Protein fibers as elementary structural and functional elements in nature inspire the engineering of protein-based products for versatile bio-medical applications. We have recently used the electrospinning process to fabricate strong sub-micron fibers made solely of serum albumin (SA). This raises the challenges of turning a globular non-viscous protein solution into a polymer--like spinnable solution and producing keratin-like fibers enriched in inter S-S bridges. A stable spinning process was achieved by using SA solution in a rich trifluoroethanol-water mixture with β-mercaptoethanol. The breakage of the intra disulfide bridges, as identified by mass spectrometry, together with the denaturing alcohol, enabled a pronounced expansion of the protein. This in turn, affects the rheological properties of the solution. X-ray diffraction pattern of the fibers revealed equatorial orientation, indicating the alignment of structures along the fiber axis. The mechanical properties reached remarkable average values (Young's modulus of 1.6GPa, and max stress of 36MPa) as compared to other fibrous protein nanofibers. These significant results are attributed to both the alignment and inter disulfide bonds (cross linking) that were formed by spontaneous post-spinning oxidation.

Projeto de acopladores ópticos utilizando algoritmo genético

OpenAIRE

Jaqueline Oliveira Zampronio

2016-01-01

Resumo: Este projeto é uma proposta de um novo acoplador óptico para a aplicação em circuitos ópticos integrados. O dispositivo foi desenvolvido utilizando o método dos elementos finitos vetorial 3D associado com o algoritmo genético e leva em consideração guias de onda com diferentes altura, largura e índices de refração. O comprimento total do acoplador óptico é de apenas 4,22 µm e o seu funcionamento é baseado em pequenos segmentos cilíndricos que interferem na propagação da onda eletromag...

Produção de hidromel utilizando mel de Melipona scutellaris

OpenAIRE

Peixoto, Samira; Carvalho, Carlos Alfredo; Estevinho, Leticia M.

2014-01-01

Atualmente, existe uma crescente procura de bebidas fermentadas por parte dos consu-midores, particularmente de hidromel, produzido empiricamente desde a antiguidade. De acordo com a literatura, este bebida tem excelentes efeitos na digestão e metabolismo e é benéfico para doentes com anemia crónica e doenças do trato gastrointestinal [1].Esta bebida é geralmente produzida utilizando mel de Apis mellifera, no entanto, no Brasil existe também mel de abelhas sem ferrão, como Melipona scutellaris...

A 'Rosetta Stone' to Interpret the UV-HST Photometry of Multiple Stellar Populations in Globular Clusters

Science.gov (United States)

Renzini, Alvio

2011-10-01

In this proposal we intend to firmly identify the chemical species responsible for the UV and UV-optical color differences exhibited by the multiple stellar populations harboured by two Galactic globular clusters: omega Centauri and 47 Tucanae, one with highly helium enriched sub-populations {omega Centauri}, the other not.We plan to collect ultraviolet STIS spectra for stars in the crowded cores of the clusters, where HST photometry is already available for thousands of stars in more than 10 filters, from F225W to F850LP. This WFC3+ACS photometric database has allowed us to show that UV colors are remarkably effective in separating the different cluster sub-populations, and with the proposed STIS spectroscopy we can quantify the chemical abundance differences among such sub-populations, most notably in Nitrogen and Oxygen. The resulting calibration of the UV colors in terms of CNO abundances will provide a new effective tool for the chemical characterization of large numbers of globular cluster stars belonging to the various sub-populations in each cluster, and to better isolate the specific role of the helium abundance.The plan is to observe at least one star for each of the main principal stellar sub-populations in each of the two clusters. These objects are selected on the basis of their accurate photometry and astrometry already in hand, based on existing UV-HST images.

Constraints on helium enhancement in the globular cluster M4 (NGC 6121): The horizontal branch test

Energy Technology Data Exchange (ETDEWEB)

Valcarce, A. A. R.; De Medeiros, J. R. [Universidade Federal do Rio Grande do Norte, Departamento de Física, 59072-970 Natal, RN (Brazil); Catelan, M. [Pontificia Universidad Católica de Chile, Centro de Astroingeniería, Av. Vicuña Mackena 4860, 782-0436 Macul, Santiago (Chile); Alonso-García, J. [Pontificia Universidad Católica de Chile, Instituto de Astrofísica, Facultad de Física, Av. Vicuña Mackena 4860, 782-0436 Macul, Santiago (Chile); Cortés, C. [Universidad Metropolitana de Ciencias de la Educación, Facultad de Ciencias Básicas, Departamento de Física, Av. José Pedro Alessandri 774, Santiago (Chile)

2014-02-20

Recent pieces of evidence have revealed that most, and possibly all, globular star clusters are composed of groups of stars that formed in multiple episodes with different chemical compositions. In this sense, it has also been argued that variations in the initial helium abundance (Y) from one population to the next are also the rule, rather than the exception. In the case of the metal-intermediate globular cluster M4 (NGC 6121), recent high-resolution spectroscopic observations of blue horizontal branch (HB) stars (i.e., HB stars hotter than the RR Lyrae instability strip) suggest that a large fraction of blue HB stars are second-generation stars formed with high helium abundances. In this paper, we test this scenario by using recent photometric and spectroscopic data together with theoretical evolutionary computations for different Y values. Comparing the photometric data with the theoretically derived color-magnitude diagrams, we find that the bulk of the blue HB stars in M4 have ΔY ≲ 0.01 with respect to the cluster's red HB stars (i.e., HB stars cooler than the RR Lyrae strip)—a result which is corroborated by comparison with spectroscopically derived gravities and temperatures, which also favor little He enhancement. However, the possible existence of a minority population on the blue HB of the cluster with a significant He enhancement level is also discussed.

Preparation and evaluation of highly drug-loaded fine globular granules using a multi-functional rotor processor.

Science.gov (United States)

Iwao, Yasunori; Kimura, Shin-Ichiro; Ishida, Masayuki; Mise, Ryohei; Yamada, Masaki; Namiki, Noriyuki; Noguchi, Shuji; Itai, Shigeru

2015-01-01

The manufacture of highly drug-loaded fine globular granules eventually applied for orally disintegrating tablets has been investigated using a unique multi-functional rotor processor with acetaminophen, which was used as a model drug substance. Experimental design and statistical analysis were used to evaluate potential relationships between three key operating parameters (i.e., the binder flow rate, atomization pressure and rotating speed) and a series of associated micromeritics (i.e., granule mean size, proportion of fine particles (106-212 µm), flowability, roundness and water content). The results of multiple linear regression analysis revealed several trends, including (1) the binder flow rate and atomization pressure had significant positive and negative effects on the granule mean size value, Carr's flowability index, granular roundness and water content, respectively; (2) the proportion of fine particles was positively affected by the product of interaction between the binder flow rate and atomization pressure; and (3) the granular roundness was negatively and positively affected by the product of interactions between the binder flow rate and the atomization pressure, and the binder flow rate and rotating speed, respectively. The results of this study led to the identification of optimal operating conditions for the preparation of granules, and could therefore be used to provide important information for the development of processes for the manufacture of highly drug-loaded fine globular granules.

Constraints on helium enhancement in the globular cluster M4 (NGC 6121): The horizontal branch test

International Nuclear Information System (INIS)

Valcarce, A. A. R.; De Medeiros, J. R.; Catelan, M.; Alonso-García, J.; Cortés, C.

2014-01-01

Recent pieces of evidence have revealed that most, and possibly all, globular star clusters are composed of groups of stars that formed in multiple episodes with different chemical compositions. In this sense, it has also been argued that variations in the initial helium abundance (Y) from one population to the next are also the rule, rather than the exception. In the case of the metal-intermediate globular cluster M4 (NGC 6121), recent high-resolution spectroscopic observations of blue horizontal branch (HB) stars (i.e., HB stars hotter than the RR Lyrae instability strip) suggest that a large fraction of blue HB stars are second-generation stars formed with high helium abundances. In this paper, we test this scenario by using recent photometric and spectroscopic data together with theoretical evolutionary computations for different Y values. Comparing the photometric data with the theoretically derived color-magnitude diagrams, we find that the bulk of the blue HB stars in M4 have ΔY ≲ 0.01 with respect to the cluster's red HB stars (i.e., HB stars cooler than the RR Lyrae strip)—a result which is corroborated by comparison with spectroscopically derived gravities and temperatures, which also favor little He enhancement. However, the possible existence of a minority population on the blue HB of the cluster with a significant He enhancement level is also discussed.

Efeito compatibilizante de copolímeros contendo segmentos líquido-cristalinos em misturas com poli(tereftalato de etileno) e um poliéster líquido-cristalino termotrópico (TLCP).

OpenAIRE

Novack, Kátia Monteiro; Stellet, Carla Andrade; Gomes, Ailton de Souza

1999-01-01

Uma série de copolímeros com segmentos líquido-cristalinos foram sintetizados por policondensação em solução a alta temperatura e misturados com poli(tereftalato de etileno) (PET) e um poliéster líquido-cristalino termotrópico (TLCP), previamente sintetizado. Os copolímeros foram utilizados com sucesso como compatibilizantes nas misturas PET/TLCP. As técnicas de caloria diferencial de varredura, análises dinâmico-mecânicas, análises térmicas e microscopia eletrônica (SEM) foram utilizad...

Deep CCD photometry in globular clusters. VII. M30

International Nuclear Information System (INIS)

Richer, H.B.; Fahlman, G.G.; Vandenberg, D.A.

1988-01-01

New UBV CCD photometry in a single field of the globular cluster M30 was obtained, and the data were used to obtain the color magnitude diagram (CMD) of the cluster, its luminosity function, and to derive fundamental cluster parameters. No blue stragglers were found, nor any evidence of a binary sequence in the data even though the field under study is only 21 core radii from the cluster center. The cluster reddening is observed to be 0.068 + or - 0.035, significantly higher than that adopted in most current papers on M30. An intercomparison of the CMDs of three very metal-poor clusters clearly shows that there is no evidence for any age difference between them. The age of M30 itself is found to be about 14 Gyr. The luminosity function of M30 is determined to be M(V) = 8. Comparison of this function with one found by Bolte (1987) at 65 core radii shows clear evidence of mass segregation in the low-mass stars. 44 references

The nature of the globular- to fibrous-actin transition.

Science.gov (United States)

Oda, Toshiro; Iwasa, Mitsusada; Aihara, Tomoki; Maéda, Yuichiro; Narita, Akihiro

2009-01-22

Actin plays crucial parts in cell motility through a dynamic process driven by polymerization and depolymerization, that is, the globular (G) to fibrous (F) actin transition. Although our knowledge about the actin-based cellular functions and the molecules that regulate the G- to F-actin transition is growing, the structural aspects of the transition remain enigmatic. We created a model of F-actin using X-ray fibre diffraction intensities obtained from well oriented sols of rabbit skeletal muscle F-actin to 3.3 A in the radial direction and 5.6 A along the equator. Here we show that the G- to F-actin conformational transition is a simple relative rotation of the two major domains by about 20 degrees. As a result of the domain rotation, the actin molecule in the filament is flat. The flat form is essential for the formation of stable, helical F-actin. Our F-actin structure model provides the basis for understanding actin polymerization as well as its molecular interactions with actin-binding proteins.

THE DISCOVERY OF REMOTE GLOBULAR CLUSTERS IN M33

International Nuclear Information System (INIS)

Huxor, A.; Ferguson, A. M. N.; Barker, M. K.; Tanvir, N. R.; Irwin, M. J.; Chapman, S. C.; Ibata, R.; Lewis, G.

2009-01-01

We present the discovery of four remote star clusters in M33, one of which is of an extended nature. Three of the clusters were discovered using survey data from the Isaac Newton Telescope Wide-Field Camera while one was discovered serendipitously in a deep image taken with the Hubble Space Telescope's Advanced Camera for Surveys. With projected radii of 38-113 arcmin (9.6-28.5 kpc for an assumed M33 distance of 870 kpc), these clusters lie significantly beyond all but one of the currently confirmed clusters in M33. The clusters have magnitudes and colors consistent with their being old to intermediate-age globular clusters (GCs). Indeed, they bear a strong resemblance to the outer halo GC population of the Milky Way and M31 in terms (V - I) 0 color. The three outermost clusters are projected on the far side of M33 with respect to M31, an asymmetry that could suggest tidal interactions have affected M33's GC distribution at large radii.

The luminosity function for globular clusters, 4: M3

International Nuclear Information System (INIS)

Simoda, Mahiro; Fukuoka, Takashi

1976-01-01

The subgiant-turnoff portion (V = 17.2 - 20.0 mag) of the luminosity function for the globular cluster M3 has been determined from photometry of the stars within the annuli 3'-8' and 6'-8' for V = 17.2 - 19.0 mag and 19.0 - 20.0 mag, respectively, by using plates taken with the Kitt Peak 2.1-m reflector. Our result shows that the luminosity function for M3 has a similar steep rise in the subgiant portion as other clusters so far studied (M5, M13, and M92), in direct conflict with the result by SANDAGE (1954, 1957). A probable cause of this discrepancy is given. Comparison with theoretical luminosity functions by SIMODA and IBEN (1970) suggests that theory and observation are not inconsistent if the initial helium abundance of M3 stars is taken to be about 20 percent. It is suggested that M13 has a larger helium abundance than M3 and M92 from the intercomparison of their luminosity functions and color-magnitude diagrams. (auth.)

Controle de plantas daninhas com cyanazine aplicado em mistura com outros herbicidas, na cultura do algodão (Gossypium hirsutum L. Weed control in cotton (Gossypium hirsutum L. with cyanazine and other herbicides

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Julio Pedro Laca-Buendia

1985-12-01

Full Text Available Com a finalidade de estudar a mistura de tanque mais eficiente com cyanazine em aplicação de pré-emergência na cultura algodoeira (Gossypium hirsutum L. , foram estudados os seguintes tratamentos: cyanazine + diuron nas doses de 0,8 + 0,8 kg i.a/ha e 1,0 + 1,0 kg i.a/ha; cyanazine+ oryzalin , nas do sés de 1,2 + 0,8 kg i.a/ha e 1,6 + 1,2 kg i.a/h a; cyanazyne + metol a chlor, nas doses de 1,4 + 2,0 kg i.a/ha e 1,75 + 2,52 kg i.a/ ha;cianazine na dose de 1,75 kg i.a /ha; oryzalin na dose de 1,12 kg i.a/ha; metol achlor na dose de 2,52 kg i.a /ha e diuron na dose de 1,6 kg i.a /ha. Para efeito de comparação, utilizou-se uma testemunha sem capina e outra com capina manual. Nenhum tratamento apresentou injúria para as plantas de algodão e não houve diferenças significativas para o "stand" inicial. Já no "stand" final, a testemunha sem capina apresentou o menor número de plantas, sendo que não houve diferenças significativas dos outros tratamentos com a testemunha capinada. Para o rendimento, a mistura cyanazine + metolachior em ambas as doses estudadas, não apresentaram diferenças significativas da testemunha capinada. Quanto à altura da planta, peso de 100 sementes, porcentagem e índice de fibras não houve diferenças significativas entre os tratamentos estudados, somente o peso do capulho foi afetado pelo oryzalin. Pela avaliação visual (EWRC 1 a 9*, os herbicidas apres entaram um controle satisfatório somente até os 30 dias após aplicação, sendo que a mistura cyanazine + metolachlor foi efici ente quanto a testemunha capinada. No controle da Portulaca oleracea , a mistura cyanazine + oryzalin na maior dose e oryzalin apresentaram 71,4% de controle ate os 30 dias e 79,4% e 82,4%, respectivamente, até 45 dias da aplicação. Para Amaranthus sp., à exceção da cyanazine e cyanazine + diuron nas doses menores, não apresentaram nenhum controle, sendo que os outros herbicidas controlaram com eficiência superior a 70

Data Analysis of Globular Cluster Harris Catalogue in View of the King Models and Their Dynamical Evolution. I. Theoretical model

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Marco Merafina

2014-12-01

Full Text Available We discuss the possibility to analyze the problem of gravothermal catastrophe in a new way, by obtaining thermodynamical equations to apply to a selfgravitating system. By using the King distribution function in the framework of statistical mechanics we treat the globular clusters evolution as a sequence of quasi-equilibrium thermodynamical states.

Young globular clusters in NGC 1316

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Sesto, Leandro A.; Faifer, Favio R.; Smith Castelli, Analía V.; Forte, Juan C.; Escudero, Carlos G.

2018-05-01

We present multi-object spectroscopy of the inner zone of the globular cluster (GC) system associated with the intermediate-age merger remnant NGC 1316. Using the multi-object mode of the GMOS camera, we obtained spectra for 35 GCs. We find pieces of evidence that the innermost GCs of NGC 1316 rotate almost perpendicular to the stellar component of the galaxy. In a second stage, we determined ages, metallicities and α-element abundances for each GC present in the sample, through the measurement of different Lick/IDS indices and their comparison with simple stellar population models. We confirmed the existence of multiple GC populations associated with NGC 1316, where the presence of a dominant subpopulation of very young GCs, with an average age of 2.1 Gyr, metallicities between -0.5 < [Z/H] < 0.5 dex and α-element abundances in the range -0.2 < [α/Fe] < 0.3 dex, stands out. Several objects in our sample present subsolar values of [α/Fe] and a large spread of [Z/H] and ages. Some of these objects could actually be stripped nuclei, possibly accreted during minor merger events. Finally, the results have been analyzed with the aim of describing the different episodes of star formation and thus provide a more complete picture about the evolutionary history of the galaxy. We conclude that these pieces of evidence could indicate that this galaxy has cannibalized one or more gas-rich galaxies, where the last fusion event occurred about 2 Gyr ago.

DETAILED CHEMICAL ABUNDANCES OF FOUR STARS IN THE UNUSUAL GLOBULAR CLUSTER PALOMAR 1

International Nuclear Information System (INIS)

Sakari, Charli M.; Venn, Kim A.; Irwin, Mike; Aoki, Wako; Arimoto, Nobuo; Dotter, Aaron

2011-01-01

Detailed chemical abundances for 21 elements are presented for four red giants in the anomalous outer halo globular cluster Palomar 1 (R GC = 17.2 kpc, Z = 3.6 kpc) using high-resolution (R = 36, 000) spectra from the High Dispersion Spectrograph on the Subaru Telescope. Pal 1 has long been considered unusual because of its low surface brightness, sparse red giant branch, young age, and its possible association with two extragalactic streams of stars. This paper shows that its chemistry further confirms its unusual nature. The mean metallicity of the four stars, [Fe/H] = -0.60 ± 0.01, is high for a globular cluster so far from the Galactic center, but is low for a typical open cluster. The [α/Fe] ratios, though in agreement with the Galactic stars within the 1σ errors, agree best with the lower values in dwarf galaxies. No signs of the Na/O anticorrelation are detected in Pal 1, though Na appears to be marginally high in all four stars. Pal 1's neutron-capture elements are also unusual: its high [Ba/Y] ratio agrees best with dwarf galaxies, implying an excess of second-peak over first-peak s-process elements, while its [Eu/α] and [Ba/Eu] ratios show that Pal 1's contributions from the r-process must have differed in some way from normal Galactic stars. Therefore, Pal 1 is unusual chemically, as well in its other properties. Pal 1 shares some of its unusual abundance characteristics with the young clusters associated with the Sagittarius dwarf galaxy remnant and the intermediate-age LMC clusters, and could be chemically associated with the Canis Majoris overdensity; however, it does not seem to be similar to the Monoceros/Galactic Anticenter Stellar Stream.

The globular cluster system of NGC 1316. II. The extraordinary object SH2

Science.gov (United States)

Richtler, T.; Kumar, B.; Bassino, L. P.; Dirsch, B.; Romanowsky, A. J.

2012-07-01

Context. SH2 has been described as an isolated HII-region, located about 6.5' south of the nucleus of NGC 1316 (Fornax A), a merger remnant in the the outskirts of the Fornax cluster of galaxies. Aims: We give a first, preliminary description of the stellar content and environment of this remarkable object. Methods: We used photometric data in the Washington system and HST photometry from the Hubble Legacy Archive for a morphological description and preliminary aperture photometry. Low-resolution spectroscopy provides radial velocities of the brightest star cluster in SH2 and a nearby intermediate-age cluster. Results: SH2 is not a normal HII-region, ionized by very young stars. It contains a multitude of star clusters with ages of approximately 108 yr. A ring-like morphology is striking. SH2 seems to be connected to an intermediate-age massive globular cluster with a similar radial velocity, which itself is the main object of a group of fainter clusters. Metallicity estimates from emission lines remain ambiguous. Conclusions: The present data do not yet allow firm conclusions about the nature or origin of SH2. It might be a dwarf galaxy that has experienced a burst of extremely clustered star formation. We may witness how globular clusters are donated to a parent galaxy. Based on observations taken at the European Southern Observatory, Cerro Paranal, Chile, under the programmes 082.B-0680, on observations taken at the Interamerican Observatory, Cerro Tololo, Chile. Furthermore based on observations made with the NASA/ESA Hubble Space Telescope (HST, PI: A. Sandage, Prop.ID: 7504), and obtained from the Hubble Legacy Archive, which is a collaboration between the Space Telescope Science Institute (STScI/NASA), the Space Telescope European Coordinating Facility (ST-ECF/ESA) and the Canadian Astronomy Data Centre (CADC/NRC/CSA).

Chemical abundances of giant stars in NGC 5053 and NGC 5634, two globular clusters associated with the Sagittarius dwarf spheroidal galaxy?

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Sbordone, L.; Monaco, L.; Moni Bidin, C.; Bonifacio, P.; Villanova, S.; Bellazzini, M.; Ibata, R.; Chiba, M.; Geisler, D.; Caffau, E.; Duffau, S.

2015-07-01

Context. The tidal disruption of the Sagittarius dwarf spheroidal galaxy (Sgr dSph) is producing the most prominent substructure in the Milky Way (MW) halo, the Sagittarius Stream. Aside from field stars, it is suspected that the Sgr dSph has lost a number of globular clusters (GC). Many Galactic GC are thought to have originated in the Sgr dSph. While for some candidates an origin in the Sgr dSph has been confirmed owing to chemical similarities, others exist whose chemical composition has never been investigated. Aims: NGC 5053 and NGC 5634 are two of these scarcely studied Sgr dSph candidate-member clusters. To characterize their composition we analyzed one giant star in NGC 5053, and two in NGC 5634. Methods: We analyze high-resolution and signal-to-noise spectra by means of the MyGIsFOS code, determining atmospheric parameters and abundances for up to 21 species between O and Eu. The abundances are compared with those of MW halo field stars, of unassociated MW halo globulars, and of the metal-poor Sgr dSph main body population. Results: We derive a metallicity of [Fe ii/H] = -2.26 ± 0.10 for NGC 5053, and of [Fe i/H] = -1.99 ± 0.075 and -1.97 ± 0.076 for the two stars in NGC 5634. This makes NGC 5053 one of the most metal-poor globular clusters in the MW. Both clusters display an α enhancement similar to the one of the halo at comparable metallicity. The two stars in NGC 5634 clearly display the Na-O anticorrelation widespread among MW globulars. Most other abundances are in good agreement with standard MW halo trends. Conclusions: The chemistry of the Sgr dSph main body populations is similar to that of the halo at low metallicity. It is thus difficult to discriminate between an origin of NGC 5053 and NGC 5634 in the Sgr dSph, and one in the MW. However, the abundances of these clusters do appear closer to that of Sgr dSph than of the halo, favoring an origin in the Sgr dSph system. Appendix A is available in electronic form at http

Avaliação da reação de mitsuda em pacientes virchovianos inativos antes e após imunoterapia

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Maria Sueli Parreira de Arruda

1995-09-01

Full Text Available Neste estudo investigou-se o potencial imunomodulador do levamisole e da mistura BCG/Mycobacterium leprae em pacientes virchovianos inativos, utilizando como parâmetro a reação de Mitsuda. Vinte pacientes, classificados como Mitsuda histologicamente negativos há 10 anos, foram divididos em três grupos: cinco pacientes que foram somente reavaliados frente a mitsudina: oito pacientes que receberam levamisole e, sete que receberam a mistura de BCG vivo mais M. leprae morto. Os resultados mostraram que: 1 o levamisole não alterou a reatividade à mitsudina em nenhum dos casos estudados; 2 as modificações da reatividade verificadas com o uso da mistura (tres casos ou aquelas que ocorreram espontaneamente (tres casos foram sempre de pequena amplitude e refletiram variações próprias de pacientes com algum grau de resistência ao Mycobacterium leprae.In this study the immunopotentiator levamisole as well as a mixture of BCGMycobacterium leprae were investigated in inactive lepromatous leprosy patients by using the Mitsuda reaction as a parameter. Twenty lepromatous patients ten years ago classified as histologically negative for Mitsuda's test were divided into three groups: five patients that were only retested with Mitsuda antigen; eight patients that received oral levamisol and seven patients that received a mixture of alive BCG plus autoclaved M. leprae.The results indicated that: 1 the levamisole did not alter the reactivity to lepromin in any of the patients studied 2 neither the changes in the reactivity to lepromin by using the mixture (3 cases nor those that occurred spontaneously (3 cases were clear. They properly reflected the natural variation of patients with some degree of resistance to Mycobacterium leprae.

La resolución de problemas geométricos en Matemática utilizando la computadora

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Osmany Guzmán-Simón

2017-11-01

Full Text Available Se presenta un análisis donde se plantean los fundamentos psicopedagógicos que sustentan el desarrollo de habilidades en la resolución de problemas geométricos en la asignatura Matemática, utilizando la computadora.

Development of globular embryos from the hybridization between 'Pêra Rio' sweet orange and 'Poncã' mandarin Desenvolvimento de embriões globulares de citros provenientes de hibridação entre laranjeira 'Pêra Rio' x tangerineira 'Poncã'

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Edvan Alves Chagas

2003-12-01

Full Text Available This research was undertaken to study the influence of different concentrations of the MT medium, sucrose, vitamins, activated charcoal and gibberellic acid (GA3 on the culture of immature embryos from the crossing between 'Pêra Rio' sweet orange and 'PONCÃ' mandarin. The embryos were excised under aseptic conditions and inoculated in 15 mL of the MT medium according to the following experiments: 1 MT concentrations (0%, 50%, 100%, 150% and 200% supplemented with 0, 30, 60 and 90 g.L-1 of sucrose; 2 vitamins concentrations of the MT (0%, 50%, 100%, 150% and 200% supplemented with 0, 30, 60 and 90 g.L-1 of sucrose; 3 activated charcoal concentrations (0, 0.5, 1, 1.5 and 2 g.L-1 supplemented with GA3 (0, 0.01, 0.1; 1 and 10 mg.L-1. After the inoculation, the embryos were kept in a growth room for 90 days at 27 ± 1ºC, in a 16-hour photoperiod with 32 µmol.m-2.s-1 of irradiance. The best development of embryos at the globular stage was achieved using 50% and 100% of the MT medium plus 60 g.L-1 and 90 g.L-1 of sucrose, respectively, supplemented with 0.01 mg.L-1 of GA3. The addition of activated charcoal or vitamins in the MT medium has shown to be unnecessary to the development of globular embryos.Objetivou-se estudar a influência de diversas concentrações do meio MT, sacarose, vitaminas, carvão ativado e ácido giberélico no cultivo de embriões imaturos oriundos do cruzamento entre laranjeira 'Pêra Rio' x tangerineira 'PONCÃ' . Os embriões foram excisados sob condições assépticas e inoculados em 15 mL do meio de cultura MT, de acordo com cada experimento a seguir: 1 concentrações do meio de cultura MT (0%, 50%, 100%, 150% e 200% combinados com 0, 30, 60 e 90 g.L-1 de sacarose; 2 concentrações de vitaminas do meio MT (0%, 50%, 100%, 150% e 200% combinados com 0, 30, 60 e 90 g.L-1 de sacarose e; 3 concentrações de carvão ativado (0; 0.5; 1; 1.5 e 2 g.L-1 combinados com GA3 (0; 0.01; 0.1; 1 e 10 mg.L-1. Após a inoculação, os

Análise do desenvolvimento morfológico da blenda polimérica PBT/ABS durante as etapas de mistura por extrusão e moldagem por injeção Analysis of the morphological development of PBT/ABS blends during the extrusion and injection molding processes

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Edson N. Ito

2004-06-01

Full Text Available O enfoque principal deste trabalho foi observar o desenvolvimento da morfologia de fases da blenda binária PBT/ABS e desta blenda compatibilizada pela adição de um copolímero acrílico reativo, durante a etapa de mistura por extrusão e de moldagem por injeção. A evolução da morfologia das blendas, durante a etapa de mistura, foi analisada através do uso de amostras coletadas de uma extrusora de rosca dupla co-rotacional, com acessório especialmente projetado para coleta in line. A morfologia observada nas amostras obtidas por injeção foi realizada utilizando amostras retiradas de corpos de prova moldados. As amostras obtidas por extrusão e por moldagem por injeção foram posteriormente preparadas através de crio-ultramicrotomia e observadas através de microscopia eletrônica de transmissão (TEM. Uma "Função Dispersão" foi desenvolvida neste trabalho para comparar as diversas morfologias sob diferentes condições de processamento e de compatibilização. A adição de compatibilizante favorece a formação de uma morfologia de domínios de ABS dispersos em PBT, ao longo do canhão da extrusora, e previne satisfatoriamente o fenômeno de coalescência destes domínios durante o processo de moldagem por injeção. A função dispersão foi utilizada principalmente para mostrar a tendência da evolução morfológica e mostrou um bom desempenho para tal.The aim of this work was to observe the development of the phase morphology of the PBT/ABS blends during their extrusion mixing and injection molding steps. The evolution of the blend morphology during the mixing stage was analyzed using a specially designed co-rotational twin-screw extruder with a collecting device located along the barrel. Blend samples were collected in-line along the length of the extruder barrel during the blending process. Blend morphology was also observed from specimens molded through injection molding. All the samples were observed by transmission

A single population of red globular clusters around the massive compact galaxy NGC 1277

Science.gov (United States)

Beasley, Michael A.; Trujillo, Ignacio; Leaman, Ryan; Montes, Mireia

2018-03-01

Massive galaxies are thought to form in two phases: an initial collapse of gas and giant burst of central star formation, followed by the later accretion of material that builds up their stellar and dark-matter haloes. The systems of globular clusters within such galaxies are believed to form in a similar manner. The initial central burst forms metal-rich (spectrally red) clusters, whereas more metal-poor (spectrally blue) clusters are brought in by the later accretion of less-massive satellites. This formation process is thought to result in the multimodal optical colour distributions that are seen in the globular cluster systems of massive galaxies. Here we report optical observations of the massive relic-galaxy candidate NGC 1277—a nearby, un-evolved example of a high-redshift ‘red nugget’ galaxy. We find that the optical colour distribution of the cluster system of NGC 1277 is unimodal and entirely red. This finding is in strong contrast to other galaxies of similar and larger stellar mass, the cluster systems of which always exhibit (and are generally dominated by) blue clusters. We argue that the colour distribution of the cluster system of NGC 1277 indicates that the galaxy has undergone little (if any) mass accretion after its initial collapse, and use simulations of possible merger histories to show that the stellar mass due to accretion is probably at most ten per cent of the total stellar mass of the galaxy. These results confirm that NGC 1277 is a genuine relic galaxy and demonstrate that blue clusters constitute an accreted population in present-day massive galaxies.

New 2MASS near-infrared photometry for globular clusters in M31

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Wang, Song; Ma, Jun; Wu, Zhenyu; Zhou, Xu, E-mail: majun@nao.cas.cn [Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)

2014-07-01

We present Two Micron All Sky Survey JHK {sub s} photometry for 913 star clusters and candidates in the field of M31, which are selected from the latest Revised Bologna Catalog of M31 globular clusters (GCs) and candidates. The photometric measurements in this paper supplement this catalog, and provide the most comprehensive and homogeneous photometric catalog for M31 GCs in the JHK {sub s} bandpasses. In general, our photometry is consistent with previous measurements. The globular cluster luminosity function (GCLF) peaks for the confirmed GCs derived by fitting a t {sub 5} distribution using the maximum likelihood method are J{sub 0}=15.348{sub −0.208}{sup +0.206}, H{sub 0}=14.703{sub −0.180}{sup +0.176}, and K{sub s0}=14.534{sub −0.146}{sup +0.142}, all of which agree well with previous studies. The GCLFs are different between metal-rich (MR) and metal-poor (MP), and between inner and outer subpopulations, as MP clusters are fainter than their MR counterparts and the inner clusters are brighter than the outer ones, which confirm previous results. The NIR colors of the GC candidates are on average redder than those of the confirmed GCs, which leads to an obscure bimodal distribution of color indices. The relation of (V – K {sub s}){sub 0} and metallicity shows a notable departure from linearity, with a shallower slope toward the redder end. The color-magnitude diagram (CMD) and color-color diagram show that many GC candidates are located out of the evolutionary tracks, suggesting that some of them may be false M31 GC candidates. The CMD also shows that the initial mass function of M31 GCs covers a large range, and the majority of the clusters have initial masses between 10{sup 3} and 10{sup 6} M {sub ☉}.

Ação de acibenzolar-s-methyl isolado e em mistura com fungicidas no controle da requeima da batata Action of acibenzolar-S-methyl, isolated and in a mixture with fungicides on potato late blight control

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Jesus G. Töfoli

2005-07-01

Full Text Available Visando avaliar o desempenho de acibenzolar-S-methyl (BTH isolado e em mistura com os fungicidas mancozeb, chlorothalonil e metaxyl-M+chlorothalonil no controle da requeima da batata, foram realizados dois experimentos em cultivos comerciais nos municípios paulistas de Pilar do Sul (cv. Baraka e Bragança Paulista (cv. Asterix, de maio a agosto e agosto a outubro de 2001, respectivamente. O delineamento experimental foi o de blocos ao acaso com 4 repetições, com cada parcela medindo 25 m². Durante os experimentos foram realizadas um total de 10 pulverizações, a intervalos de 5 a 10 dias com pulverizador costal munido de barra de aplicação contendo 5 bicos TXKV26, pressão constante (4 bar e volume médio de 800 L/ha. Avaliou-se a severidade nas folhas (0 a 100%, nas hastes ( escala de notas de 1 a 5 e a produtividade comercial de tubérculos. O BTH apresentou efeitos significativos de controle quando utilizado isolado e em mistura com fungicidas de contato e sistêmico. Os maiores aumentos relativos de produtividade foram verificados para as misturas de BTH com mancozeb e chlorothalonil.To evaluate the performance of acibenzolar-S-methyl (BTH, alone and mixed with mancozeb, chlorothalonil and metaxyl-M+chlorothalonil, for the control of potato late blight, two experiments were carried out in commercial crops in the counties of Pilar do Sul (cv. Baraka and Bragança Paulista (cv. Asterix, state of São Paulo, Brazil, from May to August and August to October 2001, respectively. The experimental design was of randomized blocks with four replications, with each plot measuring 25 m². A total of 10 sprayings was done at 5- to 10-day intervals with a backpack sprayer using a 5-nozzle (TXKV26 spray wand, constant pressure of 4 bars (58 psi and average volume of 800 L/ha. Evaluations were done in regard to the severity on the leaves (0 to 100%, on the stems (score from 1 to 5 and the commercial yield of tubers. BTH presented expressive effects

Access to gram scale amounts of functional globular adiponectin from E. coli inclusion bodies by alkaline-shock solubilization.

Science.gov (United States)

Heiker, John T; Klöting, Nora; Blüher, Matthias; Beck-Sickinger, Annette G

2010-07-16

The adipose tissue derived protein adiponectin exerts anti-diabetic, anti-inflammatory and anti-atherosclerotic effects. Adiponectin serum concentrations are in the microgram per milliliter range in healthy humans and inversely correlate with obesity and metabolic disorders. Accordingly, raising circulating adiponectin levels by direct administration may be an intriguing strategy in the treatment of obesity-related metabolic disorders. However production of large amounts of recombinant adiponectin protein is a primary obstacle so far. Here, we report a novel method for large amount production of globular adiponectin from E. coli inclusion bodies utilizing an alkaline-shock solubilization method without chaotropic agents followed by precipitation of the readily renaturing protein. Precipitation of the mildly solubilized protein capitalizes on advantages of inclusion body formation. This approach of inclusion body protein recovery provides access to gram scale amounts of globular adiponectin with standard laboratory equipment avoiding vast dilution or dialysis steps to neutralize the pH and renature the protein, thus saving chemicals and time. The precipitated protein is readily renaturing in buffer, is of adequate purity without a chromatography step and shows biological activity in cultured MCF7 cells and significantly lowered blood glucose levels in mice with streptozotocin induced type 1 diabetes. Copyright 2010 Elsevier Inc. All rights reserved.

FURTHER DEFINITION OF THE MASS-METALLICITY RELATION IN GLOBULAR CLUSTER SYSTEMS AROUND BRIGHTEST CLUSTER GALAXIES

International Nuclear Information System (INIS)

Cockcroft, Robert; Harris, William E.; Wehner, Elizabeth M. H.; Whitmore, Bradley C.; Rothberg, Barry

2009-01-01

We combine the globular cluster (GC) data for 15 brightest cluster galaxies and use this material to trace the mass-metallicity relations (MMRs) in their globular cluster systems (GCSs). This work extends previous studies which correlate the properties of the MMR with those of the host galaxy. Our combined data sets show a mean trend for the metal-poor subpopulation that corresponds to a scaling of heavy-element abundance with cluster mass Z ∼ M 0.30±0.05 . No trend is seen for the metal-rich subpopulation which has a scaling relation that is consistent with zero. We also find that the scaling exponent is independent of the GCS specific frequency and host galaxy luminosity, except perhaps for dwarf galaxies. We present new photometry in (g',i') obtained with Gemini/GMOS for the GC populations around the southern giant ellipticals NGC 5193 and IC 4329. Both galaxies have rich cluster populations which show up as normal, bimodal sequences in the color-magnitude diagram. We test the observed MMRs and argue that they are statistically real, and not an artifact caused by the method we used. We also argue against asymmetric contamination causing the observed MMR as our mean results are no different from other contamination-free studies. Finally, we compare our method to the standard bimodal fitting method (KMM or RMIX) and find our results are consistent. Interpretation of these results is consistent with recent models for GC formation in which the MMR is determined by GC self-enrichment during their brief formation period.

BVI CCD photometry of the broad main-sequence globular cluster NGC 1851

International Nuclear Information System (INIS)

Alcaino, G.; Liller, W.; Alvarado, F.; Wenderoth, E.

1990-01-01

Three-color CCD C-M diagrams are presented for the globular cluster NGC 1851, showing an extreme breadth of the main-sequence, similar to that of Omega Centauri. It is found that the main-sequence turnoff points are located at V(TO) = 19.44 + or - 0.10, with colors at B-V = 0.54 + or - 0.02, V-I = 0.61 + or - 0.02, and B-I = 1.15 + or - 0.03. The best fit to the VandenBerg and Bell (1985) isochrones is shown to be all C-M diagrams with Y = 0.20, Fe/H abundance ratio = -1.27, and (m-M)v = 15.45. It is concluded that NGC 1851 has a Delta V(TO - HB) = 3.34 + or - 0.10 and an age of 16 + or - 2 Gyr. 29 refs

A spectroscopic study of chemical abundances in the globular cluster Omega Centauri

International Nuclear Information System (INIS)

Caldwell, S.P.

1987-10-01

Blue spectra at a resolution of 0.5 A of red giants in the globular clusters Omega Centauri and NGCs 288, 362, 6397 and 6809 (M55) have been obtained with the Anglo-Australian Telescope. The observations were made to test Sweigart and Mengel's [Astrophy S. J. 229, 624] theory of mixing of nuclearly-processed material to the star's surface, and to elucidate the relationship between primordial and evolutionary origins for the range in abundance within Omega Cen. The Omega Cen stars were chosen in two groups either side of the giant branch, covering the luminosity range where the onset of mixing was predicted to occur. Abundances of C, N, Fe and other heavy elements have been determined by fitting synthetic spectra, calculated from model atmospheres, to the observational data. (author)

Isolated ellipticals and their globular cluster systems. III. NGC 2271, NGC 2865, NGC 3962, NGC 4240, and IC 4889

Science.gov (United States)

Salinas, R.; Alabi, A.; Richtler, T.; Lane, R. R.

2015-05-01

As tracers of star formation, galaxy assembly, and mass distribution, globular clusters have provided important clues to our understanding of early-type galaxies. But their study has been mostly constrained to galaxy groups and clusters where early-type galaxies dominate, leaving the properties of the globular cluster systems (GCSs) of isolated ellipticals as a mostly uncharted territory. We present Gemini-South/GMOS g'i' observations of five isolated elliptical galaxies: NGC 3962, NGC 2865, IC 4889, NGC 2271, and NGC 4240. Photometry of their GCSs reveals clear color bimodality in three of them, but remains inconclusive for the other two. All the studied GCSs are rather poor with a mean specific frequency SN ~ 1.5, independently of the parent galaxy luminosity. Considering information from previous work as well, it is clear that bimodality and especially the presence of a significant, even dominant, population of blue clusters occurs at even the most isolated systems, which casts doubts on a possible accreted origin of metal-poor clusters, as suggested by some models. Additionally, we discuss the possible existence of ultra-compact dwarfs around the isolated elliptical NGC 3962. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Science and Technology Facilities Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciência, Tecnologia e Inovação (Brazil) and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina).Globular cluster photometry is available in electronic form at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/577/A59Appendices are available in

Multicolor photometric study of M31 globular clusters

International Nuclear Information System (INIS)

Fan Zhou; Ma Jun; Zhou Xu

2009-01-01

We present the photometry of 30 globular clusters (GCs) and GC candidates in 15 intermediate-band filters covering the wavelength region from ∼3000 to ∼10000 A using the archival CCD images of M31 observed as part of the Beijing - Arizona - Taiwan - Connecticut (BATC) Multicolor Sky Survey. We transform these intermediate-band photometric data into the photometry in the standard U BV RI broad-bands. These M31 GC candidates are selected from the Revised Bologna Catalog (RBC V.3.5), and most of these candidates do not have any photometric data. Therefore, the presented photometric data are a supplement to the RBC V.3.5. We find that 4 out of 61 GCs and GC candidates in RBC V.3.5 do not show any signal on the BATC images at their locations. By applying a linear fit of the distribution in the color-magnitude diagram of blue GCs and GC candidates using data from the RBC V.3.5, in this study, we find the 'blue-tilt' of blue M31 GCs with a high confidence at 99.95% or 3.47σ for the confirmed GCs, and > 99.99% or 4.87σ for GCs and GC candidates. (research papers)

Aplicação de misturas de diuron com MSMA, e com paraquat, no controle de plantas daninhas de folhas largas em cultura de algodão (Gossypium hirsutum L. Mixture of diuron whit MSMA and with paraquat for broadleaved weeds control in cotton

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L. S. P. Cruz

1978-01-01

Full Text Available Em ensaio de campo conduzido em 1975/76 procurou-se avaliar a ação de misturas de MSMA com diuron e de paraquat com diuron, aplicadas em pós-emergência, em jato dirigido, em duas épocas diferentes, no controle de algumas plantas daninhas de folhas largas em algodão: carrapicho- do-campo (Acanthospermum australe (Loef O. Kuntze , falsa-poaia (Borreria ala ta (Aubl DC, poaia-branca (Richardia brasiliensis Gomez e guanxuma (Sida spp . A vegetação natural da área do ensaio era formada ainda pela gramínea capim-de-colchão (Digitaria sanguinalis (L. Scop . Os resultados mostraram que as misturas de 2,00 kg e 2,70 kg/ha de MSMA com, respectivamente 0,30 kg e 0,40 kg/ha de diuron, e a mistura de 0.60 kg/ha de paraquat com 0,60 kg/ ha de diuron, foram eficientes no co ntro le daquelas dicotiledôneas, e também no da gramínea. Todos os tratamentos provocaram leves sintomas de fitotoxicidade nos algodoeiros, mas desapareceram depois e não prejudicaram o desenvolvimento vegetativo das plantas, assim como a produção de algodão em caroço.In a field trial carried out in 1975/76, a diuron mixtu re with MSMA and another with paraquat was tested on broadleaved weeds in cotton crops. The applications were done in postemergence, directed-spray, in two different periods. The broadleaved weeds observed in the trial were Acanthospermum australe , Borreria alata, Richardia brasiliensis, and Sida spp, also the grass Digitaria sanguinalis. Best results were obtained with the mixture of 0,60 kg/ha of paraquat with 0,60 kg/ha of diuron, and 2,70 kg/ha of MSMA with 0,40 kg/ ha of diuron, or 2,00 kg/ha of MSMA with 0,30 kg/ha of diuron. All the treatments caused sl ight symptons of toxic ity in cotton, which disappeared later and did not damage the production.

SEARCH FOR PULSED {gamma}-RAY EMISSION FROM GLOBULAR CLUSTER M28

Energy Technology Data Exchange (ETDEWEB)

Wu, J. H. K.; Kong, A. K. H.; Huang, R. H. H.; Tam, P. H. T. [Institute of Astronomy and Department of Physics, National Tsing Hua University, Hsinchu, Taiwan (China); Hui, C. Y. [Department of Astronomy and Space Science, Chungnam National University, Daejeon (Korea, Republic of); Wu, E. M. H.; Takata, J.; Cheng, K. S., E-mail: wuhkjason@gmail.com, E-mail: cyhui@cnu.ac.kr [Department of Physics, University of Hong Kong, Pokfulam Road (Hong Kong)

2013-03-10

Using the data from the Large Area Telescope on board the Fermi Gamma-ray Space Telescope, we have searched for {gamma}-ray pulsations from the direction of the globular cluster M28 (NGC 6626). We report the discovery of a signal with a frequency consistent with that of the energetic millisecond pulsar (MSP) PSR B1821-24 in M28. A weighted H-test test statistic of 28.8 is attained, which corresponds to a chance probability of {approx}10{sup -5} (4.3{sigma} detection). With a phase-resolved analysis, the pulsed component is found to contribute {approx}25% of the total observed {gamma}-ray emission from the cluster. However, the unpulsed level provides a constraint for the underlying MSP population and the fundamental plane relations for the scenario of inverse Compton scattering. Follow-up timing observations in radio/X-ray are encouraged to further investigate this periodic signal candidate.

Novas raças, novas doenças: a possibilidade colonizadora por meio da mistura racial em History of Brazil (1810-1819 de Robert Southey

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Flávia Florentino Varella

Full Text Available Resumo A possibilidade de o clima alterar o temperamento de pessoas não nativas de determinada região era crença difundida desde antes do descobrimento da América. As mudanças de ar, temperatura e alimentação, acreditava-se, poderiam contribuir decisivamente para a degeneração ou o florescimento das raças. No Novo Mundo, as raças negra, europeia e indígena foram mescladas, reconfigurando doenças europeias. Exploro neste artigo como, na avaliação do historiador Robert Southey, essa mistura de raças foi tida como bastante positiva, principalmente a do indígena com a do português, que gerava o mameluco. Os paulistas, que eram mamelucos, foram apresentados em History of Brazil como herdeiros do temperamento empreendedor português e da infatigabilidade indígena.

Síntese enzimática de ascorbil oleato utilizando tecnologias alternativas

OpenAIRE

Balen, Manuela

2016-01-01

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia de Alimentos, Florianópolis, 2016. A produção enzimática de ascorbil oleato utilizando como substratos Lascórbico e ácido oleico necessita da total solubilização entre substratos a fim de se obter maiores rendimentos. Contudo, o ácido L-ascórbico e ácido oleico não são totalmente miscíveis por possuírem polaridades bastante distintas. Assim, este trabalho objetivou bus...

Optimization of extrusion process for production of nutritious pellets Otimização do processo de extrusão para a produção de pellets nutricional

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Ernesto Aguilar-Palazuelos

2012-03-01

Full Text Available A blend of 50% Potato Starch (PS, 35% Quality Protein Maize (QPM, and 15% Soybean Meal (SM were used in the preparation of expanded pellets utilizing a laboratory extruder with a 1.5 × 20.0 × 100.0 mm die-nozzle. The independent variables analyzed were Barrel Temperature (BT (75-140 °C and Feed Moisture (FM (16-30%. The effect of extrusion variables was investigated in terms of Expansion Index (EI, apparent density (ApD, Penetration Force (PF and Specific Mechanical Energy (SME, viscosity profiles, DSC, crystallinity by X-ray diffraction, and Scanning Electronic Microscopy (SEM. The PF decreased from 30 to 4 kgf with the increase of both independent variables (BT and FM. SME was affected only by FM, and decreased with the increase in this variable. The optimal region showed that the maximum EI was found for BT in the range of 123-140 °C and 27-31% for FM, respectively. The extruded pellets obtained from the optimal processing region were probably not completely degraded, as shown in the structural characterization. Acceptable expanded pellets could be produced using a blend of PS, QPM, and SM by extrusion cooking.Neste trabalho foram elaborados pellets expandidos a partir da mistura de 50% de Amido de Batata (AB, 35% de Milho de Qualidade Protéica (MQP e 15% de Farelo de Soja (FS, utilizando extrusor de laboratório com matriz de 1,5 × 20,0 × 100,0 mm. As variáveis independentes analisadas foram: Temperatura de Extrusão (TE (75-140 °C e Umidade da Mistura (UM (16-30%. O efeito das variáveis de extrusão foram estudadas quanto ao Índice de Expansão (IE, a densidade aparente (DA, força de penetração (FP, Energia Mecânica Específica (EME, perfil de viscosidade, DSC, cristalinidade através de difração de raio X e Microscopia Eletrônica de Varredura (MEV. A PF diminuiu de 30 para 4 kgf com o aumento de ambas as variáveis independentes (TE e UM. EME foi afetada somente pela UM, diminuindo com o aumento desta variável. A regi

Anti-helium flux as a signature for antimatter globular clusters in our galaxy

International Nuclear Information System (INIS)

Belotskij, K.M.; Golubkov, Yu.A.; Khlopov, M.Yu.; Konoplich, R.V.; Sakharov, A.S.

2000-01-01

The alpha magnetic spectrometer experiment is shown to be sensitive to test the hypothesis on the existence of antimatter globular cluster in our Galaxy. The hypothesis follows from the analysis of possible tests for the mechanisms of baryosynthesis and uses antimatter domain in the matter domain Universe as the probe for the physics underlaying the origin of the matter. The interval of masses for the antimatter in our Galaxy is fixed from below by the condition of antimatter domain survival in the matter dominated Universe and from above by the observed gamma-ray flux. For this interval the expected fluxes of anti-helium-3 and anti-helium-4 are calculated with the account of their interaction with the matter in the Galaxy [ru

Anti-helium flux as a signature for antimatter globular clusters in our galaxy

International Nuclear Information System (INIS)

Belotsky, K.M.; Golubkov, Yu.A.; Khlopov, M.Yu.; Konoplich, R.V.; Sakharov, A.S.

2000-01-01

The Alpha Magnetic Spectrometer experiment is shown to be sensitive to test the hypothesis on the existence of antimatter globular cluster in our Galaxy. The hypothesis follows from the analysis of possible tests for the mechanisms of baryosynthesis and uses antimatter domains in the matter-dominated Universe as the probe for the physics underlying the origin of matter. The interval of masses for the antimatter in our Galaxy is fixed from below by the condition of antimatter domain survival in the matter-dominated Universe and from above by the observed gamma-ray flux. For this interval, the expected fluxes of anti-helium-3 and anti-helium-4 are calculated with account for their interaction with the matter in the Galaxy

A binary origin for 'blue stragglers' in globular clusters.

Science.gov (United States)

Knigge, Christian; Leigh, Nathan; Sills, Alison

2009-01-15

Blue stragglers in globular clusters are abnormally massive stars that should have evolved off the stellar main sequence long ago. There are two known processes that can create these objects: direct stellar collisions and binary evolution. However, the relative importance of these processes has remained unclear. In particular, the total number of blue stragglers found in a given cluster does not seem to correlate with the predicted collision rate, providing indirect support for the binary-evolution model. Yet the radial distributions of blue stragglers in many clusters are bimodal, with a dominant central peak: this has been interpreted as an indication that collisions do dominate blue straggler production, at least in the high-density cluster cores. Here we report that there is a clear, but sublinear, correlation between the number of blue stragglers found in a cluster core and the total stellar mass contained within it. From this we conclude that most blue stragglers, even those found in cluster cores, come from binary systems. The parent binaries, however, may themselves have been affected by dynamical encounters. This may be the key to reconciling all of the seemingly conflicting results found to date.

KINEMATICS OF OUTER HALO GLOBULAR CLUSTERS IN M31

International Nuclear Information System (INIS)

Veljanoski, J.; Ferguson, A. M. N.; Bernard, E. J.; Peñarrubia, J.; Mackey, A. D.; Huxor, A. P.; Irwin, M. J.; Chapman, S. C.; Côté, P.; Tanvir, N. R.; McConnachie, A.; Ibata, R. A.; Martin, N. F.; Fardal, M.; Lewis, G. F.

2013-01-01

We present the first kinematic analysis of the far outer halo globular cluster (GC) population in the Local Group galaxy M31. Our sample contains 53 objects with projected radii of ∼20-130 kpc, 44 of which have no previous spectroscopic information. GCs with projected radii ∼> 30 kpc are found to exhibit net rotation around the minor axis of M31, in the same sense as the inner GCs, albeit with a smaller amplitude of 79 ± 19 km s –1 . The rotation-corrected velocity dispersion of the full halo GC sample is 106 ± 12 km s –1 , which we observe to decrease with increasing projected radius. We find compelling evidence for kinematic coherence among GCs that project on top of halo substructure, including a clear signature of infall for GCs lying along the northwest stream. Using the tracer mass estimator, we estimate the dynamical mass of M31 within 200 kpc to be M M31 = (1.2-1.5) ± 0.2 × 10 12 M ☉ . This value is highly dependent on the chosen model and assumptions within.

N-body modeling of globular clusters: detecting intermediate-mass black holes by non-equipartition in HST proper motions

Science.gov (United States)

Trenti, Michele

2010-09-01

Intermediate Mass Black Holes {IMBHs} are objects of considerable astrophysical significance. They have been invoked as possible remnants of Population III stars, precursors of supermassive black holes, sources of ultra-luminous X-ray emission, and emitters of gravitational waves. The centers of globular clusters, where they may have formed through runaway collapse of massive stars, may be our best chance of detecting them. HST studies of velocity dispersions have provided tentative evidence, but the measurements are difficult and the results have been disputed. It is thus important to explore and develop additional indicators of the presence of an IMBH in these systems. In a Cycle 16 theory project we focused on the fingerprints of an IMBH derived from HST photometry. We showed that an IMBH leads to a detectable quenching of mass segregation. Analysis of HST-ACS data for NGC 2298 validated the method, and ruled out an IMBH of more than 300 solar masses. We propose here to extend the search for IMBH signatures from photometry to kinematics. The velocity dispersion of stars in collisionally relaxed stellar systems such as globular clusters scales with main sequence mass as sigma m^alpha. A value alpha = -0.5 corresponds to equipartition. Mass-dependent kinematics can now be measured from HST proper motion studies {e.g., alpha = -0.21 for Omega Cen}. Preliminary analysis shows that the value of alpha can be used as indicator of the presence of an IMBH. In fact, the quenching of mass segregation is a result of the degree of equipartition that the system attains. However, detailed numerical simulations are required to quantify this. Therefore we propose {a} to carry out a new, larger set of realistic N-body simulations of star clusters with IMBHs, primordial binaries and stellar evolution to predict in detail the expected kinematic signatures and {b} to compare these predictions to datasets that are {becoming} available. Considerable HST resources have been invested in

Diseño de la ampliación de la red de comunicación de EMELNORTE utilizando fibra óptica y tecnología inalámbrica

OpenAIRE

Román Vásquez, Roberto Xavier; Hidalgo Lascano, Pablo William

2010-01-01

El presente proyecto de titulación aborda la descripción de las técnicas de transmisión de datos utilizando fibra óptica y tecnología inalámbrica. Presenta además, el diseño detallado de la ampliación de la red utilizando enlaces de comunicación requeridos por EMELNORTE para la integración de sus estaciones operativas que se encuentran distribuidas en toda su área de concesión utilizando los medios de transmisión citados. Los enlaces se dimensionan de manera que soporten la transmisión de da...

A simple model for electrical charge in globular macromolecules and linear polyelectrolytes in solution

Science.gov (United States)

Krishnan, M.

2017-05-01

We present a model for calculating the net and effective electrical charge of globular macromolecules and linear polyelectrolytes such as proteins and DNA, given the concentration of monovalent salt and pH in solution. The calculation is based on a numerical solution of the non-linear Poisson-Boltzmann equation using a finite element discretized continuum approach. The model simultaneously addresses the phenomena of charge regulation and renormalization, both of which underpin the electrostatics of biomolecules in solution. We show that while charge regulation addresses the true electrical charge of a molecule arising from the acid-base equilibria of its ionizable groups, charge renormalization finds relevance in the context of a molecule's interaction with another charged entity. Writing this electrostatic interaction free energy in terms of a local electrical potential, we obtain an "interaction charge" for the molecule which we demonstrate agrees closely with the "effective charge" discussed in charge renormalization and counterion-condensation theories. The predictions of this model agree well with direct high-precision measurements of effective electrical charge of polyelectrolytes such as nucleic acids and disordered proteins in solution, without tunable parameters. Including the effective interior dielectric constant for compactly folded molecules as a tunable parameter, the model captures measurements of effective charge as well as published trends of pKa shifts in globular proteins. Our results suggest a straightforward general framework to model electrostatics in biomolecules in solution. In offering a platform that directly links theory and experiment, these calculations could foster a systematic understanding of the interrelationship between molecular 3D structure and conformation, electrical charge and electrostatic interactions in solution. The model could find particular relevance in situations where molecular crystal structures are not available or

Diseño de multiplicador de 64 bits utilizando la técnica de barrido superpuesto

OpenAIRE

Montalvo Ramírez, Luis

1987-01-01

Se presenta el desarrollo del novel algoritmo de multiplicación por barrido superpuesto de 3-bits, así como también los aspectos importantes del diseño de la arquitectura, redes lógicas y layout de un multiplicador de 64-bits utilizando como caso de estudio.

Tratamento de resíduo líquido de laticínios utilizando Caixas de Gordura e Reator Anaeróbio Compartimentado seguido de Leitos Cultivados

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Ana Cristina Ferreira Moreira da Silva

2014-10-01

Full Text Available Neste trabalho foram avaliados o desempenho e a eficiência de um sistema de tratamento de resíduos líquidos de laticínios na remoção da carga orgânica do resíduo em uma indústria de laticínios, utilizando um sistema composto por caixas de gordura, reator anaeróbio compartimentado e leitos cultivados de fluxo subsuperficial vegetado com Typha sp. e utilizando como meio suporte brita #1, sob diferentes tempos de detenção hidráulica (3 e 5 dias nos leitos cultivados. Como média geral na remoção de DBO e de DQO, o tratamento utilizando tempo de detenção de 3 dias conseguiu remover 98,87% de DBO e  99,77% de DQO, enquanto o tratamento utilizando 5 dias de detenção hidráulica removeu, em média, 99,51% de DBO e 99,56% de DQO. Os resultados indicam que o sistema foi eficiente no tratamento de resíduos líquidos de laticínios.

Tratamiento del lactosuero utilizando la técnica de electrodiálisis

OpenAIRE

Ávila G., Rita M.; Medina, Ana Luisa; Cadenas A., Reinaldo A.

2006-01-01

Tratamiento del lactosuero utilizando la técnica de electrodiálisis (Ávila G., Rita M.; Cadenas A., Reinaldo A. y Medina, Ana Luisa) Resumen El lactosuero es un subproducto de la elaboración de quesos y mantequillas. Este subproducto contiene una cantidad importante de proteínas y calcio, entre otros componentes, que hacen atractivo su tratamiento con el objeto de adecuarlo para su comercialización directa o para elaborar bebidas lácteas. Los sueros ácidos y/o salados no son ap...

Análisis de paneles solares térmicos utilizando software gratuito

OpenAIRE

Castellanos Cordeiro-Crespo, Antonio

2009-01-01

El objetivo de este proyecto es la evaluación de dos programas que trabajan en la simulación de paneles termosolares: KOLEKTOR Y CODEPRO. Para la valoración de dichos software tomaremos datos en el panel solar con el que cuenta la Universidad Politécnica de Cracovia. Después simularemos, utilizando las aplicaciones a estudio, introduciendo las mismas condiciones de la toma de datos, y compararemos los resultados obtenidos en ambos procedimientos. Lo más positivo es que ambos software son bast...

Avaliação de oxigenadores de sangue utilizando principios de transferencia de massa e tecnica de perda de carga

OpenAIRE

Luis Melchert Faber Schmutzler

2004-01-01

Resumo: Oxigenadores de sangue tipo de membrana são construídos para trocarem gases de respiração através de uma área de contato, a sua chamada área de troca. Devido a características do processo de fabricação, esta área pode softer variações. Neste trabalho procurou-se desenvolver métodos de avaliação da variação desta área, por meio da medição da transferência de massa e da perda de carga. A técnica utilizando transferência de massa gerou dois métodos de avaliação, um utilizando como fase l...

Produção de mudas do tipo rebentão, utilizando coroas de três cultivares de abacaxi inoculadas com fungos micorrízicos

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Paulo Cesar dos Santos

2011-09-01

Full Text Available Um dos principais gargalos para o desenvolvimento da abacaxicultura no Brasil tem sido a ausência tanto de mudas em quantidade quanto em qualidade, para propagação. Entre as alternativas, verifica-se a obtenção de mudas a partir da brotação de gemas de coroas dos frutos, que são, normalmente, descartadas pelo consumidor. Além disso, a utilização de fungos micorrízicos arbusculares (FMAs pode ser uma alternativa para melhorar a produção das mudas, visto que estes fungos podem abreviar o tempo de formação de mudas de diversas frutíferas. O objetivo deste trabalho foi avaliar a produção de mudas do tipo rebentão, através do método de destruição do meristema apical da coroa de cultivares do abacaxizeiro inoculadas com FMAs. Utilizou-se o delineamento em blocos casualizados, num fatorial 3x3, com três cultivares de abacaxi ('Smooth Cayenne', 'Pérola' e 'Jupi' e três tratamentos microbiológicos (Sem inoculação, inoculação com Glomus etunicatum e inoculação com uma mistura dos fungos Glomus clarum e Gigaspora margarita, com quatro repetições. As primeiras emissões foram registradas aos 30; 60 e 90 dias após o plantio para as cultivares 'Smooth Cayenne', 'Pérola' e 'Jupi', respectivamente. O abacaxizeiro 'Smooth Cayenne' produziu 80 e 69% de mudas a mais do que as cultivares 'Pérola' e 'Jupi', respectivamente. Coroas de abacaxi inoculadas com a mistura de fungos micorrízicos apresentaram maior número de emissão de brotações quando comparadas com aquelas inoculadas apenas com G. etunicatum. Nas avaliações nutricionais das coroas, a inoculação com a mistura de dois fungos micorrizicos promoveu, em folhas da coroa do abacaxizeiro, incrementos de 85 e 66% nos teores de P; de 22 e 13% para os de N, e de 6 e 19% para os de K, em relação aos tratamentos G. etunicatum e sem inoculação, respectivamente. Conclui-se que a produção de rebentos oriundos de coroas cuja gema principal foi decapitada é uma

Operação periódica de um leito gotejante de carvão ativado para redução da emissão do poluente atmosférico SO2 com geração de ácido sulfúrico.

OpenAIRE

Sandro Megale Pizzo

2003-01-01

O desempenho dos modos periódico e contínuo de operação para o tratamento de uma mistura gasosa de SO2 em ar foi analisado utilizando-se um reator de aço inox, em escala de bancada de 77,92mm de diâmetro interno, contendo leito fixo de carvão ativado de 80,00mm de altura, com partículas de 2,00 a 2,36mm. Foram obtidas as eficiências médias de remoção do gás e as concentrações de ácido sulfúrico produzido nas soluções líquidas de saída, em função da concentração inicial de SO2 (500, 1.000 e 1....

Evolution of highly compact binary stellar systems in globular clusters

International Nuclear Information System (INIS)

Krolik, J.H.; Meiksin, A.; Joss, P.C.

1984-01-01

We have calculated the secular evolution of a highly compact binary stellar system, composed of a collapsed object and a low-mass secondary star, in the core of a globular cluster. The binary evolves under the combined influences of (i) gravitational radiation losses from the system, (ii) the evolution of the secondary star, (iii) the resultant gradual mass transfer, if any, from the secondary to the collapsed object, and (iv) occasional encounters with passing field stars. We calculate all these effects in detail, utilizing some simplifying approximations appropriate to low-mass secondaries. The times of encounters with field stars, and the initial parameter specifying those encounters, were chosen by use of a Monte Carlo technique; the subsequent gravitational interactions were calculated utilzing a three-body integrator, and the changes in the binary orbital parmeters were thereby determined. We carried out a total of 20 such evolutionary calculations for each of two cluster core densities (1 and 3 x 10 3 stars pc -3 ). Each calculation was continued until the binary was disrupted or until 2 x 10 10 yr had elapsed

Spectroscopy of chromospheric lines of giants in the globular cluster

Science.gov (United States)

Dupree, A. K.; Hartmann, Lee; Smith, Graeme H.; Rodgers, A. W.; Roberts, W. H.; Zucker, D. B.

1994-01-01

Spectroscopic observations of chromospheric transitions (Mg II, H-alpha, and Ca II K) from two red giants (A31 and A59) in the globular cluster NGC 6572 were made with the Goddard High Resolution Spectrograph on the Hubble Space Telescope and the coude spectrograph of the 1.9 m telescope at the Mount Stromlo Observatory. These measurements give evidence for chromospheric activity and outward motions within the atmospheres. The surface flux of the Mg II emission is comparable to that in disk population giants of similar (B-V) color. The Mg II profiles are asymmetric, which is most likely caused by absorption in an expanding stellar atmosphere and/or by possible interstellar features. Notches are found in the core of the H-alpha line of A59, which are similar to those found in Cepheids. This suggests that shocks are present in the atmosphere of A59 and indicates that hydrodynamic phenomena are influencing the levvel of chromospheric emission and producing upper atmospheric motions which may lead to mass loss.

Immunochemical and autoantigenic properties of the globular domain of basement membrane collagen (type IV).

Science.gov (United States)

von der Mark, H; Oberbäumer, I; Timpl, R; Kemler, R; Wick, G

1985-02-01

Polyclonal rabbit antibodies raised against the globular domain NC1 of collagen IV from human placenta and a mouse tumor react with conformational antigenic determinants present on the NC1 hexamers and also with the three major subunits obtained after dissociation. The antibodies recognized unique structures within basement membranes and showed a broad tissue reactivity but only limited species cross-reactivity. Using these antibodies, it was possible to detect small amounts of collagen IV antigens from cell cultures and in serum. Monoclonal rat antibodies against mouse NC1 revealed a similar reaction potential. Autoantibodies could be produced in mice against mouse NC1 which react with kidney and lung basement membranes in a pathological manner, mimicking Goodpasture syndrome.

Estudo de misturas asfálticas com ligante modificado pelo polímero EVA para pavimentos urbanos de Manaus - AM Study of asphalt mixtures containing a binder modified with EVA polymer for use in urban pavements in Manaus

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Daniela M. G. D'Antona

2011-01-01

Full Text Available A presente pesquisa buscou soluções com materiais alternativos visando à construção de pavimentos urbanos para Manaus (AM com maior vida útil e condizente com as suas condições de serviço, em particular, o seu desempenho mecânico frente às temperaturas regionais. Estudou-se o ligante regional, CAP 50/70, misturado com 4% do polímero EVA, e como partícipe em compósitos asfálticos. A incorporação do mencionado polímero teve como objetivo melhorar suas propriedades reológicas e, por conseguinte, o comportamento mecânico desse compósito - concreto asfáltico, empregado como revestimento nas vias urbanas da Capital do Estado do Amazonas. Os ligantes (virgem e modificado foram caracterizados conforme a especificação da ANP e a metodologia Superpave. As misturas asfálticas foram avaliadas pelo ensaio de fluência por compressão axial, com carregamento dinâmico à temperatura de 40 ºC. O material asfáltico modificado com EVA (AMP EVA demonstrou melhores propriedades reológicas ou equivalentes ao asfalto convencional (REMAN, ao longo de todos os ensaios de caracterização. As misturas alternativas compostas com o CAP modificado (SEVA obtiveram desempenho mecânico superior ao de misturas com cimento asfáltico habitualmente comercializado na região (SMAN.In this research we investigated alternative materials to build urban pavements in Manaus, seeking for pavements with longer lifetime for usage and suitable mechanical properties to withstand the local temperatures. The asphaltic mixtures contained a regional binder, namely CAP 50/70, mixed with 4% of EVA polymer. The incorporation of the latter polymer was aimed at improving the rheological properties of asphaltic concrete used in roads in the Amazonas' capital. The asphalt binders (original and modified were characterized in accordance with the ANP (National Petroleum Agency specification and the Superpave methodology. The asphalt mixtures had their mechanical properties

The SAGES Legacy Unifying Globulars and Galaxies survey (SLUGGS): sample definition, methods, and initial results

Energy Technology Data Exchange (ETDEWEB)

Brodie, Jean P.; Romanowsky, Aaron J.; Jennings, Zachary G.; Pota, Vincenzo; Kader, Justin; Roediger, Joel C.; Villaume, Alexa; Arnold, Jacob A.; Woodley, Kristin A. [University of California Observatories, 1156 High Street, Santa Cruz, CA 95064 (United States); Strader, Jay [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Forbes, Duncan A.; Pastorello, Nicola; Usher, Christopher; Blom, Christina; Kartha, Sreeja S. [Centre for Astrophysics and Supercomputing, Swinburne University, Hawthorn, VIC 3122 (Australia); Foster, Caroline; Spitler, Lee R., E-mail: jbrodie@ucsc.edu [Australian Astronomical Observatory, P.O. Box 915, North Ryde, NSW 1670 (Australia)

2014-11-20

We introduce and provide the scientific motivation for a wide-field photometric and spectroscopic chemodynamical survey of nearby early-type galaxies (ETGs) and their globular cluster (GC) systems. The SAGES Legacy Unifying Globulars and GalaxieS (SLUGGS) survey is being carried out primarily with Subaru/Suprime-Cam and Keck/DEIMOS. The former provides deep gri imaging over a 900 arcmin{sup 2} field-of-view to characterize GC and host galaxy colors and spatial distributions, and to identify spectroscopic targets. The NIR Ca II triplet provides GC line-of-sight velocities and metallicities out to typically ∼8 R {sub e}, and to ∼15 R {sub e} in some cases. New techniques to extract integrated stellar kinematics and metallicities to large radii (∼2-3 R {sub e}) are used in concert with GC data to create two-dimensional (2D) velocity and metallicity maps for comparison with simulations of galaxy formation. The advantages of SLUGGS compared with other, complementary, 2D-chemodynamical surveys are its superior velocity resolution, radial extent, and multiple halo tracers. We describe the sample of 25 nearby ETGs, the selection criteria for galaxies and GCs, the observing strategies, the data reduction techniques, and modeling methods. The survey observations are nearly complete and more than 30 papers have so far been published using SLUGGS data. Here we summarize some initial results, including signatures of two-phase galaxy assembly, evidence for GC metallicity bimodality, and a novel framework for the formation of extended star clusters and ultracompact dwarfs. An integrated overview of current chemodynamical constraints on GC systems points to separate, in situ formation modes at high redshifts for metal-poor and metal-rich GCs.

Adiabatic invariants in stellar dynamics, 3: Application to globular cluster evolution

Science.gov (United States)

Weinberg, Martin D.

1994-01-01

The previous two companion papers demonstrate that slowly varying perturbations may not result in adiabatic cutoffs and provide a formalism for computing the long-term effects of time-dependent perturbations on stellar systems. Here, the theory is implemented in a Fokker-Planck code and a suite of runs illustrating the effects of shock heating on globular cluster evolution are described. Shock heating alone results in considerable mass loss for clusters with R(sub g) less than or approximately 8 kpc: a concentration c = 1.5 cluster with R(sub g) kpc loses up to 95% of its initial mass in 15 Gyr. Only those with concentration c greater than or approximately 1.3 survive disk shocks inside of this radius. Other effects, such as mass loss by stellar evolution, will decrease this survival bound. Loss of the initial halo together with mass segregation leads to mass spectral indices, x, which may be considerably larger than their initial values.

Image processing of globular clusters - Simulation for deconvolution tests (GlencoeSim)

Science.gov (United States)

Blazek, Martin; Pata, Petr

2016-10-01

This paper presents an algorithmic approach for efficiency tests of deconvolution algorithms in astronomic image processing. Due to the existence of noise in astronomical data there is no certainty that a mathematically exact result of stellar deconvolution exists and iterative or other methods such as aperture or PSF fitting photometry are commonly used. Iterative methods are important namely in the case of crowded fields (e.g., globular clusters). For tests of the efficiency of these iterative methods on various stellar fields, information about the real fluxes of the sources is essential. For this purpose a simulator of artificial images with crowded stellar fields provides initial information on source fluxes for a robust statistical comparison of various deconvolution methods. The "GlencoeSim" simulator and the algorithms presented in this paper consider various settings of Point-Spread Functions, noise types and spatial distributions, with the aim of producing as realistic an astronomical optical stellar image as possible.

SANS study of understanding mechanism of cold gelation of globular proteins

International Nuclear Information System (INIS)

Chinchalikar, A. J.; Kumar, Sugam; Aswal, V. K.; Wagh, A. G.; Kohlbrecher, J.

2014-01-01

Small-angle neutron scattering (SANS) has been used to probe the evolution of interaction and the resultant structures in the cold gelation of globular proteins. The cold gelation involves two steps consisting of irreversible protein deformation by heating followed by some means (e.g. increasing ionic strength) to bring them together at room temperature. We have examined the role of different salts in cold gelation of preheated aqueous Bovine Serum Albumin (BSA) protein solutions. The interactions have been modeled by two Yukawa potential combining short-range attraction and long-range repulsion. We show that in step 1 (preheated temperature effect) the deformation of protein increases the magnitude of attractive interaction but not sufficient to induce gel. The attractive interaction is further enhanced in step 2 (salt effect) to result in gel formation. The salt effect is found to be strongly depending on the valency of the counterions. The gel structure has been characterized by the mass fractals

CHEMICAL ABUNDANCE EVIDENCE OF ENDURING HIGH STAR FORMATION RATES IN AN EARLY-TYPE GALAXY: HIGH [Ca/Fe] IN NGC 5128 GLOBULAR CLUSTERS

International Nuclear Information System (INIS)

Colucci, Janet E.; Durán, María Fernanda; Bernstein, Rebecca A.; McWilliam, Andrew

2013-01-01

We present [Fe/H], ages, and Ca abundances for an initial sample of 10 globular clusters in NGC 5128 obtained from high-resolution, high signal-to-noise ratio echelle spectra of their integrated light. All abundances and ages are obtained using our original technique for high-resolution integrated light abundance analysis of globular clusters. The clusters have a range in [Fe/H] between –1.6 and –0.2. In this sample, the average [Ca/Fe] for clusters with [Fe/H] <–0.4 is +0.37 ± 0.07, while the average [Ca/Fe] in our Milky Way (MW) and M31 GC samples is +0.29 ± 0.09 and +0.24 ± 0.10, respectively. This may imply a more rapid chemical enrichment history for NGC 5128 than for either the MW or M31. This sample provides the first quantitative picture of the chemical history of NGC 5128 that is directly comparable to what is available for the MW. Data presented here were obtained with the MIKE echelle spectrograph on the Magellan Clay Telescope

CHEMICAL ABUNDANCE EVIDENCE OF ENDURING HIGH STAR FORMATION RATES IN AN EARLY-TYPE GALAXY: HIGH [Ca/Fe] IN NGC 5128 GLOBULAR CLUSTERS

Energy Technology Data Exchange (ETDEWEB)

Colucci, Janet E.; Duran, Maria Fernanda; Bernstein, Rebecca A. [Department of Astronomy and Astrophysics, 1156 High Street, UCO/Lick Observatory, University of California, Santa Cruz, CA 95064 (United States); McWilliam, Andrew, E-mail: jcolucci@ucolick.org [Observatories of the Carnegie Institute of Washington, 813 Santa Barbara Street, Pasadena, CA 91101-1292 (United States)

2013-08-20

We present [Fe/H], ages, and Ca abundances for an initial sample of 10 globular clusters in NGC 5128 obtained from high-resolution, high signal-to-noise ratio echelle spectra of their integrated light. All abundances and ages are obtained using our original technique for high-resolution integrated light abundance analysis of globular clusters. The clusters have a range in [Fe/H] between -1.6 and -0.2. In this sample, the average [Ca/Fe] for clusters with [Fe/H] <-0.4 is +0.37 {+-} 0.07, while the average [Ca/Fe] in our Milky Way (MW) and M31 GC samples is +0.29 {+-} 0.09 and +0.24 {+-} 0.10, respectively. This may imply a more rapid chemical enrichment history for NGC 5128 than for either the MW or M31. This sample provides the first quantitative picture of the chemical history of NGC 5128 that is directly comparable to what is available for the MW. Data presented here were obtained with the MIKE echelle spectrograph on the Magellan Clay Telescope.

CARACTERIZACIÓN DINÁMICA DE UNA MEZCLA ASFÁLTICA SOMETIDA A LAS CONDICIONES AMBIENTALES DE BOGOTÁ CARACTERIZAÇÃO DINÂMICA DE UMA MISTURA ASFÁLTICA SUBMETIDA Às CONDIÇÕES AMBIENTAIS DE BOGOTÁ DYNAMIC CHARACTERIZATION OF AN ASPHALT MIXTURE EXPOSED TO ENVIRONMENTAL CONDITIONS OF BOGOTÁ

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Hugo Alexander Rondón

2010-12-01

Full Text Available El artículo presenta el cambio que experimentan el módulo resiliente, la deformación vertical permanente y la ley de fatiga de una mezcla de concreto asfáltico cuando es expuesta a las condiciones climáticas de la ciudad de Bogotá D.C. (Colombia durante 29 meses. La tendencia de la mezcla con el tiempo de exposición es a producirse un aumento en los valores de rigidez, debido principalmente a procesos de endurecimiento por envejecimiento del ligante asfáltico. Este aumento en rigidez genera incremento de la resistencia a la deformación permanente y disminución de la vida de fatiga de la mezcla analizada. Con base en la evolución del módulo resiliente con el tiempo de exposición al medio ambiente se propone una ecuación para predecir de manera aproximada el cambio que ocurre en la vida a la fatiga de la mezcla.O artigo apresenta a mudança que experimentam o módulo de resiliência, a deformação vertical permanente e a lei de fadiga de uma mistura de concreto asfáltico quando é exposta às condições climáticas da cidade de Bogotá D.C. (Colômbia durante 29 meses. A tendência da mistura com o tempo de exposição é a produzir-se um aumento nos valores de rigidez, devido principalmente a processos de endurecimento por envelhecimento do ligante asfáltico. Este aumento em rigidez gera incremento da resistência à deformação permanente e diminuição da vida de fadiga da mistura analisada. Com base na evolução do módulo de resiliência com o tempo de exposição ao médio ambiente propõe-se uma equação para predizer de maneira aproximada a mudança que ocorre na vida à fadiga da mistura.The paper presents the evolution of the resilient modulus, permanent vertical deformation, and fatigue law of hot mix asphalt (HMA when exposed to the weather conditions in the city of Bogotá D.C. (Colombia for 29 months. The trend of mixture with the exposure time is to experience an increase in stiffness values, mainly due to age

TESTING STELLAR POPULATION SYNTHESIS MODELS WITH SLOAN DIGITAL SKY SURVEY COLORS OF M31's GLOBULAR CLUSTERS

International Nuclear Information System (INIS)

Peacock, Mark B.; Zepf, Stephen E.; Maccarone, Thomas J.; Kundu, Arunav

2011-01-01

Accurate stellar population synthesis models are vital in understanding the properties and formation histories of galaxies. In order to calibrate and test the reliability of these models, they are often compared with observations of star clusters. However, relatively little work has compared these models in the ugriz filters, despite the recent widespread use of this filter set. In this paper, we compare the integrated colors of globular clusters in the Sloan Digital Sky Survey (SDSS) with those predicted from commonly used simple stellar population (SSP) models. The colors are based on SDSS observations of M31's clusters and provide the largest population of star clusters with accurate photometry available from the survey. As such, it is a unique sample with which to compare SSP models with SDSS observations. From this work, we identify a significant offset between the SSP models and the clusters' g - r colors, with the models predicting colors which are too red by g - r ∼ 0.1. This finding is consistent with previous observations of luminous red galaxies in the SDSS, which show a similar discrepancy. The identification of this offset in globular clusters suggests that it is very unlikely to be due to a minority population of young stars. The recently updated SSP model of Maraston and Stroembaeck better represents the observed g - r colors. This model is based on the empirical MILES stellar library, rather than theoretical libraries, suggesting an explanation for the g - r discrepancy.

Aproximaciones al valor de la integral definida utilizando una calculadora graficadora

OpenAIRE

Ansola, Esther; Rodríguez, Eugenio Carlos; Hernández, Nelson; Gómez, Pablo Ignacio; Alfonso, Débora Oliva; Sánchez, Danelia

2008-01-01

Este trabajo muestra una experiencia llevada a cabo con un grupo de estudiantes de primer año de ingeniería a través de un curso facultativo en el que se retomó el cálculo de integrales definidas, utilizando la tecnología, con el propósito de:• Consolidar el concepto de integral definida a través de su definición y de su interpretación geométrica. • Mostrar otras formas de calcular una integral definida mediante aproximaciones numéricas y su interpretación geométrica. El recurso tecnológic...

Control de velocidad de un motor de inducción utilizando un controlador Fuzzy

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Madelín Lima Álvarez

2011-03-01

Full Text Available Se realiza la simulación del sistema de control de velocidad del motor de inducción. Se parte del enfoquevectorial y de un sistema de coordenadas adecuado a su futura utilización, utilizando para esto el lenguaje desimulación de sistemas dinámicos Simulink. En cuanto a la simulación del método de control vectorial porcampo orientado se ha empleado el denominado método de control vectorial indirecto. El control de la velocidaddel motor se simuló utilizando un controlador Fuzzy, comparándose posteriormente estos resultados con losobtenidos mediante la utilización de un controlador PI digital.  This work carries out the simulation of speed control of induction motor. It is based on the field orientation theoryand on a system of coordinates adapted to its future use. The language that has been used for the simulation ofdynamics systems is Simulink. The indirect method of the field orientation control theory was used in themathematical analysis of the induction motor. The speed control of the induction motor was simulated using aFuzzy controller and these results were compared with those obtained by means of the use of a PI digitalcontroller.

Caracterização microestrutural e comportamento mecânico das ligas de alumínio AA2139 T3 e T8 soldadas por fricção rotativa com mistura Microstructural characterization and mechanical behavior of an AA2139 T3 and T8 aluminum alloy joined by friction stir welding (FSW

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Vinícius Toledo Saccon

2010-12-01

Full Text Available Este trabalho visou analisar a caracterização microestrutural e o comportamento mecânico das ligas de alumínio AA2139 T3 e T8 quando são soldadas pelo processo Soldagem por Fricção Rotativa com Mistura, o qual é realizado na fase sólida. A análise microestrutural foi realizada utilizando microscopia óptica e eletrônica de varredura, e o comportamento mecânico foi avaliado através de medidas de microdureza e ensaio de tração convencional complementado pelo sistema ARAMIS. As ligas foram soldadas nos mesmos parâmetros de soldagem e com a mesma ferramenta, a fim de avaliar a qualidade da junta soldada para as duas condições de tratamento térmico, T3 e T8. Os resultados obtidos mostraram soldas resistentes para ambos os tratamentos térmicos, porém com melhores propriedades mecânicas para a liga AA2139 T3.This work aimed to study the microstructural characterization and mechanical behavior of AA2139 T3 and T8 aluminum alloys joined by FSW - Friction Stir Welding. The microstructural analysis has been done using optical microscope and scanning electron microscopy, and the mechanical analysis were evaluate through microhardness testing and conventional tensile test using the ARAMIS system . Each alloy were welded using the same welding parameters and the same tool in order to evaluate the joint quality for both heat treatment used for this work, T3 and T8. The result showed sounds joints for both heat treatments, although with better mechanical properties for the alloy AA2139 T3.

High-resolution abundance analysis of red giants in the globular cluster NGC 6522

Science.gov (United States)

Barbuy, B.; Chiappini, C.; Cantelli, E.; Depagne, E.; Pignatari, M.; Hirschi, R.; Cescutti, G.; Ortolani, S.; Hill, V.; Zoccali, M.; Minniti, D.; Trevisan, M.; Bica, E.; Gómez, A.

2014-10-01

Context. The [Sr/Ba] and [Y/Ba] scatter observed in some galactic halo stars that are very metal-poor and in a few individual stars of the oldest known Milky Way globular cluster NGC 6522 have been interpreted as evidence of early enrichment by massive fast-rotating stars (spinstars). Because NGC 6522 is a bulge globular cluster, the suggestion was that not only the very-metal poor halo stars, but also bulge stars at [Fe/H] ~ -1 could be used as probes of the stellar nucleosynthesis signatures from the earlier generations of massive stars, but at much higher metallicity. For the bulge the suggestions were based on early spectra available for stars in NGC 6522, with a medium resolution of R ~ 22 000 and a moderate signal-to-noise ratio. Aims: The main purpose of this study is to re-analyse the NGC 6522 stars reported previously by using new high-resolution (R ~ 45 000) and high signal-to-noise spectra (S/N > 100). We aim at re-deriving their stellar parameters and elemental ratios, in particular the abundances of the neutron-capture s-process-dominated elements such as Sr, Y, Zr, La, and Ba, and of the r-element Eu. Methods: High-resolution spectra of four giants belonging to the bulge globular cluster NGC 6522 were obtained at the 8m VLT UT2-Kueyen telescope with the UVES spectrograph in FLAMES-UVES configuration. The spectroscopic parameters were derived based on the excitation and ionization equilibrium of Fe i and Fe ii. Results: Our analysis confirms a metallicity [Fe/H] = -0.95 ± 0.15 for NGC 6522 and the overabundance of the studied stars in Eu (with +0.2 < [Eu/Fe] < + 0.4) and alpha-elements O and Mg. The neutron-capture s-element-dominated Sr, Y, Zr, Ba, and La now show less pronounced variations from star to star. Enhancements are in the range 0.0 < [Sr/Fe] < +0.4, +0.23 < [Y/Fe] < +0.43, 0.0 < [Zr/Fe] < +0.4, 0.0 < [La/Fe] < +0.35, and 0.05 < [Ba/Fe] < +0.55. Conclusions: The very high overabundances of [Y/Fe] previously reported for the four studied

Metallicity Spreads in M31 Globular Clusters

Science.gov (United States)

Bridges, Terry

2003-07-01

Our recent deep HST photometry of the M31 halo globular cluster {GC} Mayall II, also called G1, has revealed a red-giant branch with a clear spread that we attribute to an intrinsic metallicity dispersion of at least 0.4 dex in [Fe/H]. The only other GC exhibiting such a metallicity dispersion is Omega Centauri, the brightest and most massive Galactic GC, whose range in [Fe/H] is about 0.5 dex. These observations are obviously linked to the fact that both G1 and Omega Cen are bright and massive GC, with potential wells deep enough to keep part of their gas, which might have been recycled, producing a metallicity scatter among cluster stars. These observations dramatically challenge the notion of chemical homogeneity as a defining characteristic of GCs. It is critically important to find out how common this phenomenon is and how it can constrain scenarios/models of GC formation. The obvious targets are other bright and massive GCs, which exist in M31 but not in our Galaxy where Omega Cen is an isolated giant. We propose to acquire, with ACS/HRC, deep imaging of 3 of the brightest M31 GCs for which we have observed velocity dispersion values similar to those observed in G1 and Omega Cen. A sample of GCs with chemical abundance dispersions will provide essential information about their formation mechanism. This would represent a major step for the studies of the origin and evolution of stellar populations.

Computational and theoretical studies of globular proteins

Science.gov (United States)

Pagan, Daniel L.

Protein crystallization is often achieved in experiment through a trial and error approach. To date, there exists a dearth of theoretical understanding of the initial conditions necessary to promote crystallization. While a better understanding of crystallization will help to create good crystals suitable for structure analysis, it will also allow us to prevent the onset of certain diseases. The core of this thesis is to model and, ultimately, understand the phase behavior of protein particles in solution. Toward this goal, we calculate the fluid-fluid coexistence curve in the vicinity of the metastable critical point of the modified Lennard-Jones potential, where it has been shown that nucleation is increased by many orders of magnitude. We use finite-size scaling techniques and grand canonical Monte Carlo simulation methods. This has allowed us to pinpoint the critical point and subcritical region with high accuracy in spite of the critical fluctuations that hinder sampling using other Monte Carlo techniques. We also attempt to model the phase behavior of the gamma-crystallins, mutations of which have been linked to genetic cataracts. The complete phase behavior of the square well potential at the ranges of attraction lambda = 1.15 and lambda = 1.25 is calculated and compared with that of the gammaII-crystallin. The role of solvent is also important in the crystallization process and affects the phase behavior of proteins in solution. We study a model that accounts for the contribution of the solvent free-energy to the free-energy of globular proteins. This model allows us to model phase behavior that includes solvent.

Small-angle X-ray scattering studies of thermally-induced globular protein gels

International Nuclear Information System (INIS)

Clark, A.H.; Tuffnell, C.D.

1980-01-01

Small-angle X-ray scattering has been applied to gels formed by heating globular proteins, in aqueous solution, above their unfolding temperatures. A number of BSA gels, previously characterised by electron microscopy, have been studied, and by setting up theoretical models for the scattering process, the X-ray data have been shown to be consistent with the microscope conclusions regarding network structure. It is concluded that the networks form by a linearly-directed aggregation of unfolded, disc-like, protein molecules, three-dimensional geometry being achieved by occasional branching, and/or cross-linking. Long-range inhomogeneities in network structure, easily observed by electron microscopy, and correlated with variations in pH or ionic strength, have an effect on X-ray scattering, and hence the X-ray method is sensitive not only to different network strand thicknesses, but to different degrees of uniformity as well. (author)

Violência urbana e privatização do policiamento no Brasil: uma mistura invisível

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Martha Knisely Huggins

Full Text Available Este artigo argumenta que grande parte da violência policial no mundo, em especial no Brasil, tem se tornado invisível, a despeito do caráter público dos homicídios policiais. As ideologias sobre raça e criminalidade ocultam mortes de pobres e negros sob a justificativa de que elas são uma resposta ao aumento do crime entre certos grupos da população. As organizações policiais, mediante operações militares nas favelas, caracterizam essa violência como uma "guerra contra o crime", em que os delinquentes são mais numerosos e armados que os "bons" policiais e cidadãos. A mistura entre policiamento público e privado torna difícil determinar qual das entidades de controle social provocou essas mortes, particularmente por conta da participação de policiais em serviço e fora de serviço nas empresas de segurança privada. Nesse processo, a segurança tem se convertido em uma mercadoria que separa os pobres dos ricos e os criminosos dos não-criminosos. Apesar de os pobres precisarem mais dos serviços da polícia do que os ricos, eles são percebidos como classes perigosas a serem controladas. Por sua vez, os ricos que podem comprar segurança privada utilizam-na para se proteger daqueles que são vitimizados pela segurança pública.

Emission of particulate matter from ternary blends consisting of biodiesel, ethanol and vegetable oil: a comparison with conventional dieselEmissão de material particulado por misturas ternárias compostas de biodiesel, etanol e óleo vegetal: uma comparação com o óleo diesel convencional

Directory of Open Access Journals (Sweden)

Murilo Daniel de Melo Innocentini

2011-12-01

Full Text Available The purpose of this study was to quantify the particulate matter emission from ternary blends comprehending biodiesel, ethanol and vegetable oil in a Diesel cycle engine, and an identical engine working with petrol diesel as control. To compare the fuels’ emissions, the particulate matter from the engine’s exhaust was collected, using a fiberglass circular filter paper, which was coupled by means of a steel flange at the end of the exhaust pipe. The results with ternary blends showed expressive reduction of particulate matter level exhausted by the engine, in its maximum load. We can conclude that the utilization of ternary blends, with the methods and conditions of this experiment, was efficient to reduce the emission of particulate matter contained in the exhaust gases of Diesel cycle engine.O objetivo deste trabalho foi quantificar a emissão de material particulado de misturas ternárias compostas de biodiesel, etanol e óleo vegetal em um motor de ciclo Diesel, tendo como testemunha um motor idêntico funcionando com óleo diesel de petróleo. Para a comparação da emissão dos dois combustíveis, foi realizada a coleta de material particulado proveniente dos escapamentos dos motores com um filtro circular confeccionado de fibra de vidro, que foi acoplado com um flange de aço, no final da tubulação de escape. Os resultados obtidos com a utilização das misturas ternárias de biocombustíveis indicaram uma redução expressiva no nível de material particulado emitido pelo motor em sua carga máxima. Pode-se concluir que a utilização das misturas ternárias, nas condições e métodos de realização do experimento, foi eficiente na redução de emissão de material particulado presente nos gases de exaustão do motor de ciclo Diesel.

Mistura de biodiesel de sebo bovino em motor diesel durante 600 horas Blend of biodiesel from beef tallow in a diesel engine during 600 hours of tests

Directory of Open Access Journals (Sweden)

Ila Maria Corrêa

2011-07-01

Full Text Available O biodiesel de sebo bovino é considerado uma alternativa de baixo custo e de grande disponibilidade por ser resíduo da produção agropecuária brasileira, que é uma das maiores do mundo. Raros são os trabalhos que mostram a utilização do biodiesel de sebo bovino em motores diesel. Assim, o objetivo deste trabalho foi verificar o efeito da mistura de biodiesel bovino na proporção de 5% ao óleo diesel comercial no desempenho do motor, possíveis consequências internas no motor e nas características do óleo lubrificante após o uso prolongado em motor diesel. Foram realizados ensaios em bancada dinamométrica utilizando um trator agrícola. O desempenho do motor foi determinado através da tomada de potência (TDP. O motor foi operado por 600h durante as quais foi determinada a potência, o consumo de combustível e analisadas as amostras de óleo lubrificante a cada 100h. Ao final do ensaio, o motor foi aberto e inspecionado. A análise do óleo lubrificante mostrou nível de contaminação crítico a partir das 400h, mas a inspeção visual do motor não detectou nenhum desgaste interno. O motor funcionou normalmente, embora tenha ocorrido tendência de redução na potência e aumento de consumo de combustível ao longo das 600h.Biodiesel from beef tallow has been considered a low-cost and high availability alternative due to be residue from the Brazilian livestock production, one of the world's largest. Papers that show the use of biodiesel from beef tallow in diesel engine are rare. The aim of this study was to investigate the effect of blend of biodiesel from beef tallow (B5 in commercial diesel oil on engine performance, analyzing possible internal consequences and characteristics of lubricating oil after the prolonged use in a diesel engine. Engine performance was evaluated through tractor power take off (PTO tests. The engine was operated for 600 hours. Power and fuel consumption were measured. Samples of lubricating oil were

Desenvolvimento de misturas instantâneas de mandioca e caseína: efeito do teor de proteína e parâmetros de extrusão sobre a viscosidade Development of instant blends of cassava flour and casein: effect of protein contents and extrusion parameters on viscosity

Directory of Open Access Journals (Sweden)

Beatriz Helena Borges Lustosa

2010-09-01

Full Text Available O interesse da indústria de alimentos por produtos desenvolvidos a partir de farinhas acrescidas de proteína não se deve somente às suas características nutricionais, senão também às suas propriedades funcionais e reológicas, as quais definem as suas aplicações comerciais. Este trabalho teve por objetivo avaliar o efeito de parâmetros operacionais do processo de extrusão sobre as propriedades de pasta de misturas de farinha de mandioca e caseína. O processo de extrusão seguiu o delineamento 'central composto rotacional' para três fatores: teor de proteína (2,5 a 9,5%, umidade (14,5 a 19,5% e temperatura de extrusão (65 a 135 ºC. As misturas antes e após a extrusão foram analisadas no Rapid Visco Analyser (RVA quanto a: viscosidade inicial, pico de viscosidade, quebra de viscosidade, viscosidade final e tendência à retrogradação. Os resultados obtidos nas misturas antes da extrusão mostraram aumento dos valores de viscosidade com o aumento da concentração de proteína até o ponto central (6% e, nos teores mais elevados de proteína, ocorreu redução destes. Após a extrusão, observou-se que o teor de proteína foi a variável de maior efeito sobre as propriedades de pasta, seguida pela umidade das misturas.The interest of the food industry in products developed from flours added with protein is not due only to their nutritional characteristics, but also due to their functional and rheological properties, which define their commercial applications. This study aimed to evaluate the effect of operational parameters of the extrusion process on the paste properties of cassava flour and casein blends. The process of extrusion followed the central composed rotational design with three factors: protein content (2.5 to 9.5%, moisture (14.5 to 19.5%, and extrusion temperature (65 to 135 ºC. Before and after extrusion, the blends were analyzed on a Rapid Visco Analyser using the following parameters: initial viscosity, peak

MODELAGEM DE PROCESSOS UTILIZANDO O BPMN NA FACULDADE CATÓLICA RAINHA DO SERTÃO

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Antonio Neuton da Silva Júnior

2014-06-01

Full Text Available O presente artigo apresenta o gerenciamento de negócios por processos, suas perspectivas atuais, suas vantagens, o desenvolvimento do projeto Modelagem de Processos utilizando BPMN implementado na Faculdade Católica Rainha do Sertão, as ferramentas utilizadas no projeto, a metodologia e os resultados obtidos a partir do mesmo. Ainda foi descrito os setores utilizados, a modelagem resultante das pesquisas e entrevistas e as sugestões para as melhorias dos processos modelados.

Avaliação das Tensões Residuais em Juntas Soldadas de Inconel 625 Obtidas Através da Soldagem por Fricção e Mistura Mecânica

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Guilherme Vieira Braga Lemos

Full Text Available Resumo A utilização de materiais nobres é requisito básico em aplicações onde existe um ambiente agressivo como na indústria do petróleo e nuclear. Neste panorama, a liga Inconel 625 é frequentemente utilizada como material de cladeamento no revestimento interno de dutos rígidos. Assim, as superligas de níquel exercem papel fundamental nos campos de exploração de águas profundas e, por isso, o conhecimento de métodos modernos de soldagem aplicados a estas ligas e suas consequências nos estados de tensões residuais é importante. Portanto, o presente trabalho faz uma avaliação das tensões residuais após a Soldagem por Fricção e Mistura Mecânica (SFMM em chapas soldadas de Inconel 625. A união das chapas foi realizada com rotação da ferramenta 200 e 1200 rpm e velocidade de soldagem constante (1mm/s. As medições de tensões residuais na superfície das juntas soldadas foram investigadas através da técnica de difração de raios-X. Além disso, foram avaliadas as macroestruturas e o aporte térmico de acordo com os parâmetros de soldagem empregados. Embora não existam muitos trabalhos relacionados ao processo SFMM para ligas de Inconel, provavelmente devido à sua dificuldade de soldagem, tem sido percebido um aumento na aplicação da soldagem no estado sólido como excelente alternativa para as superligas à base de níquel. Os resultados mostraram que diferentes parâmetros de processo produziram juntas soldadas distintas e, consequentemente, variações na distribuição de tensões residuais. Por fim, um aumento na velocidade de rotação da ferramenta ocasionou um aumento nas tensões residuais na zona de mistura.

Predicción de la epidemia del virus sincitial respiratorio en Bogotá, D.C., utilizando variables climatológicas

Directory of Open Access Journals (Sweden)

Gilberto González-Parra

2016-09-01

Full Text Available Introducción. El virus sincitial respiratorio es uno de los principales causantes de mortalidad de niños y adultos mayores en el mundo. Objetivo. Predecir las semanas de inicio de los brotes de infección por el virus sincitial respiratorio en Bogotá entre 2005 y 2010, utilizando variables climatológicas como variables de predicción. Materiales y métodos. Se establecieron las fechas de inicio de los brotes en niños menores de cinco años ocurridas entre 2005 y 2010, en Bogotá D.C., Colombia. Se seleccionaron las variables climatológicas utilizando una matriz de correlación y, posteriormente, se construyeron 1.020 modelos resultado de la combinación de las distintas variables climatológicas y las semanas de antelación al inicio del brote. Se seleccionaron los modelos utilizando los datos correspondientes a periodos de seis (2005-2010, cuatro (2005-2008 y dos años (2009-2010. Se determinaron los mejores modelos y las variables climatológicas más relevantes, utilizando clasificadores bayesanos ingenuos y curvas características de operación del receptor (Receiver Operating Characteristic, ROC. Resultados. Los mejores resultados se obtuvieron con los modelos que utilizaron el periodo de dos años (2009-2010 y la semana 0, con 52 y 60 % de aciertos, respectivamente. La humedad mínima fue la variable que más apareció en los mejores modelos (62 %. Los clasificadores bayesanos ingenuos permitieron establecer cuáles eran los mejores modelos para predecir la semana de inicio del brote. Conclusiones. Los resultados sugieren que los modelos en que se utilizaron la humedad mínima, la velocidad del viento y la temperatura mínima serían los modelos de predicción más eficaces.

Conformational and functional analysis of the C-terminal globular head of the reovirus cell attachment protein.

Science.gov (United States)

Duncan, R; Horne, D; Strong, J E; Leone, G; Pon, R T; Yeung, M C; Lee, P W

1991-06-01

We have been investigating structure-function relationships in the reovirus cell attachment protein sigma 1 using various deletion mutants and protease analysis. In the present study, a series of deletion mutants were constructed which lacked 90, 44, 30, 12, or 4 amino acids from the C-terminus of the 455-amino acid-long reovirus type 3 (T3) sigma 1 protein. The full-length and truncated sigma 1 proteins were expressed in an in vitro transcription/translation system and assayed for L cell binding activity. It was found that the removal of as few as four amino acids from the C-terminus drastically affected the cell binding function of the sigma 1 protein. The C-terminal-truncated proteins were further characterized using trypsin, chymotrypsin, and monoclonal and polyclonal antibodies. Our results indicated that the C-terminal portions of the mutant proteins were misfolded, leading to a loss in cell binding function. The N-terminal fibrous tail of the proteins was unaffected by the deletions as was sigma 1 oligomerization, further illustrating the discrete structural and functional roles of the N- and C-terminal domains of sigma 1. In an attempt to identify smaller, functional peptides, full-length sigma 1 expressed in vitro was digested with trypsin and subsequently with chymotrypsin under various conditions. The results clearly demonstrated the highly stable nature of the C-terminal globular head of sigma 1, even when separated from the N-terminal fibrous tail. We concluded that: (1) the C-terminal globular head of sigma 1 exists as a compact, protease-resistant oligomeric structure; (2) an intact C-terminus is required for proper head folding and generation of the conformationally dependent cell binding domain.

THE HUBBLE SPACE TELESCOPE UV LEGACY SURVEY OF GALACTIC GLOBULAR CLUSTERS. VIII. PRELIMINARY PUBLIC CATALOG RELEASE

Energy Technology Data Exchange (ETDEWEB)

Soto, M.; Bellini, A.; Anderson, J.; Van der Marel, R. P.; Brown, T. M. [Space Telescope Science Institute, San Martin Drive 3700, Baltimore, MD 21218 (United States); Piotto, G.; Granata, V.; Ortolani, S.; Nardiello, D. [Dipartimento di Fisica e Astronomia Galileo Galilei, Università di Padova, Vicolo dell’Osservatorio 3, I-35122 Padova (Italy); Bedin, L. R. [INAF-Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, I-35122 Padova (Italy); Milone, A. P. [Research School of Astronomy and Astrophysics, The Australian National University, Cotter Road, Weston, ACT, 2611 (Australia); Cool, A. M. [Department of Physics and Astronomy, San Francisco State University, 1600 Holloway Avenue, San Francisco, CA 94132 (United States); King, I. R. [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195-1580 (United States); Sarajedini, A. [Department of Astronomy, University of Florida, 211 Bryant Space Science Center, Gainesville, FL 32611 (United States); Cassisi, S. [Osservatorio Astronomico di Teramo, Via Mentore Maggini s.n.c., I-64100 Teramo (Italy); Aparicio, A.; Hidalgo, S., E-mail: mario.soto@uda.cl [Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife, Canary Islands (Spain)

2017-01-01

The Hubble Space Telescope (HST) UV Legacy Survey of Galactic Globular Clusters (GO-13297) has been specifically designed to complement the existing F606W and F814W observations of the Advanced Camera for Surveys (ACS) Globular Cluster Survey (GO-10775) by observing the most accessible 47 of the previous survey’s 65 clusters in three WFC3/UVIS filters F275W, F336W, and F438W. The new survey also adds super-solar metallicity open cluster NGC 6791 to increase the metallicity diversity. The combined survey provides a homogeneous 5-band data set that can be used to pursue a broad range of scientific investigations. In particular, the chosen UV filters allow the identification of multiple stellar populations by targeting the regions of the spectrum that are sensitive to abundance variations in C, N, and O. In order to provide the community with uniform preliminary catalogs, we have devised an automated procedure that performs high-quality photometry on the new UV observations (along with similar observations of seven other programs in the archive). This procedure finds and measures the potential sources on each individual exposure using library point-spread functions and cross-correlates these observations with the original ACS-Survey catalog. The catalog of 57 clusters we publish here will be useful to identify stars in the different stellar populations, in particular for spectroscopic follow-up. Eventually, we will construct a more sophisticated catalog and artificial-star tests based on an optimal reduction of the UV survey data, but the catalogs presented here give the community the chance to make early use of this HST Treasury survey.

Evolution of long-lived globular cluster stars. III. Effect of the initial helium spread on the position of stars in a synthetic Hertzsprung-Russell diagram

Science.gov (United States)

Chantereau, W.; Charbonnel, C.; Meynet, G.

2016-08-01

Context. Globular clusters host multiple populations of long-lived low-mass stars whose origin remains an open question. Several scenarios have been proposed to explain the associated photometric and spectroscopic peculiarities. They differ, for instance, in the maximum helium enrichment they predict for stars of the second population, which these stars can inherit at birth as the result of the internal pollution of the cluster by different types of stars of the first population. Aims: We present the distribution of helium-rich stars in present-day globular clusters as it is expected in the original framework of the fast-rotating massive stars scenario (FRMS) as first-population polluters. We focus on NGC 6752. Methods: We completed a grid of 330 stellar evolution models for globular cluster low-mass stars computed with different initial chemical compositions corresponding to the predictions of the original FRMS scenario for [Fe/H] = -1.75. Starting from the initial helium-sodium relation that allows reproducing the currently observed distribution of sodium in NGC 6752, we deduce the helium distribution expected in that cluster at ages equal to 9 and 13 Gyr. We distinguish the stars that are moderately enriched in helium from those that are very helium-rich (initial helium mass fraction below and above 0.4, respectively), and compare the predictions of the FRMS framework with other scenarios for globular cluster enrichment. Results: The effect of helium enrichment on the stellar lifetime and evolution reduces the total number of very helium-rich stars that remain in the cluster at 9 and 13 Gyr to only 12% and 10%, respectively, from an initial fraction of 21%. Within this age range, most of the stars still burn their hydrogen in their core, which widens the MS band significantly in effective temperature. The fraction of very helium-rich stars drops in the more advanced evolution phases, where the associated spread in effective temperature strongly decreases. These

Sugestões de práticas de ensino de geometria utilizando origami modular

OpenAIRE

Marília Pelinson Tridapalli

2017-01-01

O presente trabalho contém sugestões de práticas de ensino, utilizando o origami modular, que podem ser aplicadas nas aulas de geometria do Ensino Fundamental. As práticas foram desenvolvidas de maneira que o professor possa enriquecer suas aulas gastando pouco tempo no preparo, e apresentam objetos manipuláveis que tornam o processo de ensino-aprendizagem mais atrativo e significativo. Apresentamos todo o processo de elaboração dos módulos e seus respectivos encaixes para a construção, usand...

Polpação de palha de milho, utilizando-se diferentes processos organosolv

OpenAIRE

Maria Lucia Bianchi

1995-01-01

Resumo: A disponibilidade de palha de milho e a crescente procura de matérias primas alternativas que substituam a madeira na fabricação de papel, levaram à investigação da possibilidade de polpação da palha de milho, utilizando-se diferentes processos Organosolv. A palha de milho foi analisada, apresentando cerca de 13% de umidade, 1% de cinzas, 7% de extrativos, 24% de lignina Klason, 54% de celulose e 16% de polioses (por diferença), com um total de 71% de holocelulose. A análise elementar...

educARción: Desarrollo de Herramientas para el Aprendizaje Utilizando Realidad Aumentada

OpenAIRE

Guerrero Juk, Julián

2013-01-01

Se presenta un sistema para apoyar en la enseñanza de balanceo de ecuaciones químicas sencillas utilizando realidad aumentada (AR). El sistema combina elementos físicos con gráficos sintéticos para hacer tangible un proceso abstracto, y así permitir que el alumno experimente directamente el proceso de balanceo de ecuaciones, en contraste con métodos tradicionales que utilizan ecuaciones escritas en papel. Dado que el equipo que se propone para su implementación (visores, HMD) no es de uso com...

THE PECULIAR CHEMICAL INVENTORY OF NGC 2419: AN EXTREME OUTER HALO 'GLOBULAR CLUSTER'

International Nuclear Information System (INIS)

Cohen, Judith G.; Kirby, Evan N.; Huang Wenjin

2011-01-01

NGC 2419 is a massive outer halo Galactic globular cluster (GC) whose stars have previously been shown to have somewhat peculiar abundance patterns. We have observed seven luminous giants that are members of NGC 2419 with Keck/HIRES at reasonable signal-to-noise ratio. One of these giants is very peculiar, with an extremely low [Mg/Fe] and high [K/Fe] but normal abundances of most other elements. The abundance pattern does not match the nucleosynthetic yields of any supernova model. The other six stars show abundance ratios typical of inner halo Galactic GCs, represented here by a sample of giants in the nearby GC M30. Although our measurements show that NGC 2419 is unusual in some respects, its bulk properties do not provide compelling evidence for a difference between inner and outer halo GCs.

HUBBLE SPACE TELESCOPE PHOTOMETRY OF GLOBULAR CLUSTERS IN M81

International Nuclear Information System (INIS)

Nantais, Julie B.; Huchra, John P.; Zezas, Andreas; Gazeas, Kosmas; Strader, Jay

2011-01-01

We perform aperture photometry and profile fitting on 419 globular cluster (GC) candidates with m V ≤ 23 mag identified in Hubble Space Telescope/Advanced Camera for Surveys BVI imaging, and estimate the effective radii of the clusters. We identify 85 previously known spectroscopically confirmed clusters, and newly identify 136 objects as good cluster candidates within the 3σ color and size ranges defined by the spectroscopically confirmed clusters, yielding a total of 221 probable GCs. The luminosity function peak for the 221 probable GCs with estimated total dereddening applied is V ∼ (20.26 ± 0.13) mag, corresponding to a distance of ∼3.7 ± 0.3 Mpc. The blue and red GC candidates, and the metal-rich and metal-poor spectroscopically confirmed clusters, respectively, are similar in half-light radius. Red confirmed clusters are about 6% larger in median half-light radius than blue confirmed clusters, and red and blue good GC candidates are nearly identical in half-light radius. The total population of confirmed and 'good' candidates shows an increase in half-light radius as a function of galactocentric distance.

Chemical Abundance Evidence of Enduring High Star Formation Rates in an Early-type Galaxy: High [Ca/Fe] in NGC 5128 Globular Clusters

Science.gov (United States)

Colucci, Janet E.; Fernanda Durán, María; Bernstein, Rebecca A.; McWilliam, Andrew

2013-08-01

We present [Fe/H], ages, and Ca abundances for an initial sample of 10 globular clusters in NGC 5128 obtained from high-resolution, high signal-to-noise ratio echelle spectra of their integrated light. All abundances and ages are obtained using our original technique for high-resolution integrated light abundance analysis of globular clusters. The clusters have a range in [Fe/H] between -1.6 and -0.2. In this sample, the average [Ca/Fe] for clusters with [Fe/H] <-0.4 is +0.37 ± 0.07, while the average [Ca/Fe] in our Milky Way (MW) and M31 GC samples is +0.29 ± 0.09 and +0.24 ± 0.10, respectively. This may imply a more rapid chemical enrichment history for NGC 5128 than for either the MW or M31. This sample provides the first quantitative picture of the chemical history of NGC 5128 that is directly comparable to what is available for the MW. Data presented here were obtained with the MIKE echelle spectrograph on the Magellan Clay Telescope. This Letter includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.

Very Broad [O III] λλ4959, 5007 Emission from the NGC 4472 Globular Cluster RZ 2109 and Implications for the Mass of Its Black Hole X-Ray Source

Science.gov (United States)

Zepf, Stephen E.; Stern, Daniel; Maccarone, Thomas J.; Kundu, Arunav; Kamionkowski, Marc; Rhode, Katherine L.; Salzer, John J.; Ciardullo, Robin; Gronwall, Caryl

2008-08-01

We present Keck LRIS spectroscopy of the black hole-hosting globular cluster RZ 2109 in the Virgo elliptical galaxy NGC 4472. We find that this object has extraordinarily broad [O III] λ5007 and [O III] λ4959 emission lines, with velocity widths of approximately 2000 km s-1. This result has significant implications for the nature of this accreting black hole system and the mass of the globular cluster black hole. We show that the broad [O III] λ5007 emission must arise from material driven at high velocity from the black hole system. This is because the volume available near the black hole is too small by many orders of magnitude to have enough [O III]-emitting atoms to account for the observed L([O III] λ5007) at high velocities, even if this volume is filled with oxygen at the critical density for [O III] λ5007. The Balmer emission is also weak, indicating the observed [O III] is not due to shocks. We therefore conclude that the [O III] λλ4959, 5007 is produced by photoionization of material driven across the cluster. The only known way to drive significant material at high velocity is for a system accreting mass near or above its Eddington limit, which indicates a stellar-mass black hole. Since it is dynamically implausible to form an accreting stellar-mass black hole system in a globular cluster with an intermediate-mass black hole (IMBH), it appears this massive globular cluster does not have an IMBH. We discuss further tests of this conclusion, and its implications for the MBH - Mstellar and MBH - σ relations. Based on observations made at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

The globular cluster-dark matter halo connection

Science.gov (United States)

Boylan-Kolchin, Michael

2017-12-01

I present a simple phenomenological model for the observed linear scaling of the stellar mass in old globular clusters (GCs) with z = 0 halo mass in which the stellar mass in GCs scales linearly with progenitor halo mass at z = 6 above a minimum halo mass for GC formation. This model reproduces the observed MGCs-Mhalo relation at z = 0 and results in a prediction for the minimum halo mass at z = 6 required for hosting one GC: Mmin(z = 6) = 1.07 × 109 M⊙. Translated to z = 0, the mean threshold mass is Mhalo(z = 0) ≈ 2 × 1010 M⊙. I explore the observability of GCs in the reionization era and their contribution to cosmic reionization, both of which depend sensitively on the (unknown) ratio of GC birth mass to present-day stellar mass, ξ. Based on current detections of z ≳ 6 objects with M1500 10 are strongly disfavoured; this, in turn, has potentially important implications for GC formation scenarios. Even for low values of ξ, some observed high-z galaxies may actually be GCs, complicating estimates of reionization-era galaxy ultraviolet luminosity functions and constraints on dark matter models. GCs are likely important reionization sources if 5 ≲ ξ ≲ 10. I also explore predictions for the fraction of accreted versus in situ GCs in the local Universe and for descendants of systems at the halo mass threshold of GC formation (dwarf galaxies). An appealing feature of the model presented here is the ability to make predictions for GC properties based solely on dark matter halo merger trees.

Fermi Detection of a Luminous gamma-ray Pulsar in a Globular Cluster

Science.gov (United States)

Freire, P. C. C.; Abdo, A. A.; Ajello, M.; Allafort, A.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Blandford, R. D.;

DUST PRODUCTION AND MASS LOSS IN THE GALACTIC GLOBULAR CLUSTER 47 TUCANAE

International Nuclear Information System (INIS)

McDonald, I.; Zijlstra, A. A.; Boyer, M. L.; Van Loon, J. Th.

2011-01-01

Dust production among post-main-sequence stars is investigated in the Galactic globular cluster 47 Tucanae (NGC 104) based on infrared photometry and spectroscopy. We identify metallic iron grains as the probable dominant opacity source in these winds. Typical evolutionary timescales of asymptotic giant branch stars suggest the mass-loss rates we report are too high. We suggest that this is because the iron grains are small or elongated and/or that iron condenses more efficiently than at solar metallicity. Comparison to other works suggests metallic iron is observed to be more prevalent toward lower metallicities. The reasons for this are explored, but remain unclear. Meanwhile, the luminosity at which dusty mass loss begins is largely invariant with metallicity, but its presence correlates strongly with long-period variability. This suggests that the winds of low-mass stars have a significant driver that is not radiation pressure, but may be acoustic driving by pulsations.

Slow Cooling in Low Metallicity Clouds: An Origin of Globular Cluster Bimodality?

Science.gov (United States)

Fernandez, Ricardo; Bryan, Greg L.

2018-05-01

We explore the relative role of small-scale fragmentation and global collapse in low-metallicity clouds, pointing out that in such clouds the cooling time may be longer than the dynamical time, allowing the cloud to collapse globally before it can fragment. This, we suggest, may help to explain the formation of the low-metallicity globular cluster population, since such dense stellar systems need a large amount of gas to be collected in a small region (without significant feedback during the collapse). To explore this further, we carry out numerical simulations of low-metallicity Bonner-Ebert stable gas clouds, demonstrating that there exists a critical metallicity (between 0.001 and 0.01 Z⊙) below which the cloud collapses globally without fragmentation. We also run simulations including a background radiative heating source, showing that this can also produce clouds that do not fragment, and that the critical metallicity - which can exceed the no-radiation case - increases with the heating rate.

Fermi detection of a luminous γ-ray pulsar in a globular cluster.

Science.gov (United States)

2011-11-25

We report on the Fermi Large Area Telescope's detection of γ-ray (>100 mega-electron volts) pulsations from pulsar J1823-3021A in the globular cluster NGC 6624 with high significance (~7 σ). Its γ-ray luminosity, L(γ) = (8.4 ± 1.6) × 10(34) ergs per second, is the highest observed for any millisecond pulsar (MSP) to date, and it accounts for most of the cluster emission. The nondetection of the cluster in the off-pulse phase implies that it contains <32 γ-ray MSPs, not ~100 as previously estimated. The γ-ray luminosity indicates that the unusually large rate of change of its period is caused by its intrinsic spin-down. This implies that J1823-3021A has the largest magnetic field and is the youngest MSP ever detected and that such anomalous objects might be forming at rates comparable to those of the more normal MSPs.

Desarrollo de apio minimamente procesado fortificado con vitamina e, utilizando la ingenieria de matrices

OpenAIRE

MARTELO CASTAÑO, YISELL JOHAN; CORTES RODRIGUEZ, MISAEL; SUAREZ MAHECHA, HÉCTOR

2011-01-01

El objetivo de este trabajo fue desarrollar un producto minimamente procesado fortificado con vitamina E, a partir de apio (Apium graveolens L. var.dulce), utilizando la ingenieria de matrices como metodologia de obtencion de alimentos funcionales. Trozos de apio impregnados al vacio con dl¿¿tocoferol acetato emulsificado en una solucion isotonica al vegetal de NaCl, 1,2%, fueron evaluados en funcion del tiempo de almacenamiento y el envasado (con y sin vacio), en terminos de la cuantificacio...

Self-assembly dynamics for the transition of a globular aggregate to a fibril network of lysozyme proteins via a coarse-grained Monte Carlo simulation

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R. B. Pandey

2015-09-01

Full Text Available The self-organizing dynamics of lysozymes (an amyloid protein with 148 residues with different numbers of protein chains, Nc = 1,5,10, and 15 (concentration 0.004 – 0.063 is studied by a coarse-grained Monte Carlo simulation with knowledge-based residue-residue interactions. The dynamics of an isolated lysozyme (Nc = 1 is ultra-slow (quasi-static at low temperatures and becomes diffusive asymptotically on raising the temperature. In contrast, the presence of interacting proteins leads to concentration induced protein diffusion at low temperatures and concentration-tempering sub-diffusion at high temperatures. Variation of the radius of gyration of the protein with temperature shows a systematic transition from a globular structure (at low T to a random coil (high T conformation when the proteins are isolated. The crossover from globular to random coil becomes sharper upon increasing the protein concentration (i.e. with Nc = 5,10, with larger Rg at higher temperatures and concentration; Rg becomes smaller on adding more protein chains (e.g. Nc = 15 a non-monotonic response to protein concentration. Analysis of the structure factor (S(q provides an estimate of the effective dimension (D ≥ 3, globular conformation at low temperature, and D ∼ 1.7, random coil, at high temperatures of the isolated protein. With many interacting proteins, the morphology of the self-assembly varies with scale, i.e. at the low temperature (T = 0.015, D ∼ 2.9 on the scale comparable to the radius of gyration of the protein, and D ∼ 2.3 at the large scale over the entire sample. The global network of fibrils appears at high temperature (T = 0.021 with D ∼ 1.7 (i.e. a random coil morphology at large scale involving tenuous distribution of micro-globules (at small scales.

Elaboración y caracterización estructural de fibras de tereftalato de polietileno (PET) dopadas con nanocobre (0) utilizando proceso de extrusión

OpenAIRE

Guzman, A.; Cárcamo, H.; León, O.

2015-01-01

El presente estudio describe la elaboración y caracterización de una fibra sintética bactericida compuesta por Tereftalato de Polietileno reciclado (rPET) y nanopartículas de cobre (0), mediante un proceso de extrusión utilizando una extrusora monohusillo. Las nanopartículas empleadas fueron elaboradas utilizando radiación microondas y ultrasonido. Para la elaboración de la fibra se produce un masterbatch de rPET con polvo de cobre nanométrico empleando un solvente de alto punto de fusión (tr...

VizieR Online Data Catalog: HST photometry of M31 globular clusters (Federici+, 2012)

Science.gov (United States)

Federici, L.; Cacciari, C.; Bellazzini, M.; Fusi Pecci, F.; Galleti, S.; Perina, S.

2013-01-01

Tables g58.dat, g108.dat, g105.dat, g219.dat, b468.dat, g1.dat, g64.dat, g87.dat, g119.dat, g287.dat, g302.dat, g11.dat, g33.dat, g76.dat, g312.dat, g319.dat, g322.dat present the photometry of the individual stars of 17 M31 globular clusters observed with the WFPC2 on board of the HST, employing the F555W/F814W filters (Fusi Pecci et al. 1996AJ....112.1461F (FFP96), Rich et al. 2005AJ....129.2670R (R05)). The data reduction has been performed using ROMAFOT (Buonanno et al. 1983A&A...126..278B), a multicomponent fitting package purposely adapted to handle HST data, that provides as output the magnitudes and the pixel positions of the detected sources. The CTE-corrected photometric data were converted to the Johnson-Cousins V,I magnitudes according to Holtzman et al (1995PASP..107..156H). Table g351.dat presents the photometry of the individual stars of the M31 globular cluster B405-G351 observed with the HST/COSTAR-corrected FOC + the F430W/F480LP filters. The data reduction has been performed using ROMAFOT; the photometric data were converted to the Johnson-Cousins system B,V magnitudes (see FFP96). Tables gc1.dat, gc2.dat, gc3.dat, gc5.dat, gc6.dat, gc7.dat, gc8.dat, gc9.dat, gc10.dat, gc4.dat, ec1.dat, ec2.dat, ec3.dat, ec4.dat present the photometry of the individual stars of 14 M31 globular clusters observed with the WFC/ACS on board of the HST + F435W/F606W filters (see Galleti et al., 2006ApJ...650L.107G; Mackey et al., 2007ApJ...655L..85M; Mackey et al., 2006ApJ...653L.105M). The data reduction has been performed using the ACS module of DOLPHOT, a point spread function-fitting package specifically devoted to the photometry of HST data, that provides as output the magnitudes and the pixel positions of the detected sources, and a number of quality parameters for a suitable sample selection. The tables present, for the ACS chip holding the cluster, all the stars with valid measurements in both passbands, global quality flag=1, crowding parameter 23.5,and noise

Influência da adubação com torta de café na germinação do algodoeiro Efect of coffee pomace on cotton germination

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C. A. Menezes Ferraz

1963-01-01

Full Text Available São apresentados os resultados de três ensaios com a finalidade de estudar o efeito da adubação com torta de café, na germinação do algodoeiro. Oa ensaios foram instalados em estufa, em 1961, utilizando-se a torta de café isoladamente e em combinação com fosforita de Olinda ou cloreto de potássio. Num dos ensaios foi testada uma mistura que continha 75%, em pêso, de torta de café e 25% de cloreto de potássio, em comparação com cloreto de potássio isoladamente. De modo geral, houve efeito prejudicial na aplicação da mistura de torta e cloreto de potássio, salvo no caso em que foi aplicada ao lado e abaixo do nível das sementes. O cloreto de potássio, isoladamente, não prejudicou a germinação. Num segundo ensaio foi estudada a mistura tendo 50% de torta de café e 50% de fosforita de Olinda. O efeito prejudicial foi menor que no ensaio anterior a presente mistura causou maiores prejuízos à germinação quando em contacto com as sementes; o mesmo não ocorreu quando aplicada ao lado do sulco de semeação. No terceiro ensaio foram testadas diversas épocas de aplicação, com as duas misturas acima citadas e torta de café. Notou-se uma tendência de melhoria na germinação quando os adubos foram aplicados com antecedência à semeação do algodoeiro.The effect of coffee pomace alone or mixed with other fertilizers on cotton germination was studied in three experiments. In a first experiment a mixture of coffee pomace (75% plus potassium chloride (25%. was compared with the latter alone. The pomace mixture reduced germination comiderably when it was: placed near the cotton seeds. When applied about 2 inches from this seed and 1 inch, below the seed level, gave good results. Potassium chloride alotte did not reduce germination. In the second experiment coffee pomace (50% mixed with Olinda rock phosphate (50% was compared with the latter alone. Damage to germination was of a lesser degree than in the first experiment

Caracterização Agronômica E Fenológica De Genótipos De Arroz Irrigado Para Determinação De Mistura Varietal

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Jaiza Francisca Ribeiro Chagas

2018-07-01

Full Text Available Este trabalho objetivou identificar genótipos semelhantes quanto à características agronômicas e fenológicas para a formação de uma mistura varietal. O experimento foi realizado no campus de Gurupi, Universidade Federal do Tocantins. O delineamento utilizado foi o inteiramente casualizado (DIC com três repetições. Os tratamentos consistiram de 37 genótipos de arroz irrigado. As características avaliadas foram germinação, floração, altura da planta, peso das panículas, comprimento das panículas, peso de 100 grãos, forma do grão, classe do grão, presença da arista e cor das glumelas. Os resultados foram submetidos à análise de variância e as médias avaliadas pelo teste de agrupamento de Scott-Knott, ao nível de 5 % de probabilidade e análise multivariada. Evidenciou-se diferença significativa para a maioria das características estudadas, indicando variabilidade entre os genótipos. O genótipo Irri 344 chegou a floração aos 74 dias após o plantio, seguido dos cultivares Javaé e Irga 417 com 79 dias. O genótipo Eloni e o Mutante Multiespigueta da Embrapa foram os que apresentaram o ciclo mais tardio. Os genótipos com maior altura foram: Tetep com 131,3 cm e o Basmati com 128,3 cm. Para a classe do grão a maioria dos genótipos foi classificada como longo fino. Na análise multivariada houve a formação de 7 grupos. A floração foi à característica que mais influenciou na determinação dos grupos, exceto para o grupo 1 composto pelos genótipos Tetep e Basmati, que se distanciaram também em relação à altura. Os genótipos CNAI 5287, CNAI 9930 e Irri 344 não foram incluídos em nenhuma dos grupos, sendo a característica classe de grãos que determinou a maior dissimilaridade em relação aos demais grupos.  Palavras-chave: Oryza sativa, descritores morfológicos, brusone, mistura de cultivares.