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Electron collisions with the CH(2)O-H(2)O complex

FREITAS, T. C.; LIMA, M. A. P.; Canuto, Sylvio Roberto Accioly; BETTEGA, M. H. F.
Fonte: AMER PHYSICAL SOC Publicador: AMER PHYSICAL SOC
Tipo: Artigo de Revista Científica
Português
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We report cross sections for elastic collisions of low-energy electrons with the CH(2)O-H(2)O complex. We employed the Schwinger multichannel method with pseudopotentials in the static-exchange and in the static-exchange-polarization approximations for energies from 0.1 to 20 eV. We considered four different hydrogen-bonded structures for the complex that were generated by classical Monte Carlo simulations. Our aim is to investigate the effect of the water molecule on the pi* shape resonance of formaldehyde. Previous studies reported a pi* shape resonance for CH(2)O at around 1 eV. The resonance positions of the complexes appear at lower energies in all cases due to the mutual polarization between the two molecules. This indicates that the presence of water may favor dissociation by electron impact and may lead to an important effect on strand breaking in wet DNA by electron impact.; FINEP; Fundacao Araucaria; CNPq under the NSF/CNPq program[490415/2007-5]

Electrochemical investigation of the dimeric oxo-bridged ruthenium complex in aqueous solution and its incorporation within a cation-exchange polymeric film on the electrode surface for electrocatalytic activity of hydrogen peroxide oxidation

Teixeira, Marcos F. S.; Cincotto, Fernando H.; Raymundo-Pereira, Paulo A.
Fonte: Pergamon-Elsevier B.V. Ltd Publicador: Pergamon-Elsevier B.V. Ltd
Tipo: Artigo de Revista Científica Formato: 6804-6811
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Processo FAPESP: 05/01296-4; Processo FAPESP: 08/07298-7; Electrochemical behavior of oxo-bridged dinuclear ruthenium(III) complex ([(bpy)2(H(2)O)Ru(III)-O-Ru(III)(H(2)O)(bpy)2](4+)) has been studied in aqueous solution (KCl 0.5 mol L(-1)) by both cyclic and rotating disk electrode (ROE) voltammetry in order to identify and elucidate the reaction mechanism. Modified electrode containing the oxo-bridged ruthenium complex incorporated into a cation-exchange polymeric film deposited onto platinum electrode surface was studied. Cyclic voltammetry at the modified electrode in KCl solution showed a single-electron reduction/oxidation of the couple Ru(III)-O-Ru(III)/Ru(III)-O-Ru(IV). The modified electrode exhibited electrocatalytic property toward hydrogen peroxide oxidation in KCl solution with a decrease of the overpotential of 340 mV compared with the platinum electrode. The Tafel plot analyses have been used to elucidate the kinetics and mechanism of the hydrogen peroxide oxidation. The first at low overpotential region there is no significant change in the Tafel slope (similar to 0.130 V dec(-1)) with varying peroxide concentration. The second region at higher overpotential the slope values (0.91-0.47V dec(-1)) were depended on the peroxide concentration. The apparent reaction order for H(2)O(2) varies from 0.16 to 0.50 in function of the applied potential. The apparent reaction order (at constant potential) with respect to H. concentration of 10(-5) to 10(-1) mol L(-1) was 0.25. A plot of the anodic current vs. the H(2)O(2) concentration for chronoamperometry (potential fixed = +0.61 V) at the modified electrode was linear in the 1.0 x 10(-5) to 2.5 x 10(-4) mol L(-1) concentration range. (C) 2011 Elsevier Ltd. All rights reserved.

Search for the Higgs boson H-2(0) at LHC in 3-3-1 model

Cieza Montalvo, J. E.; Gil Ramirez, R. J.; Ramirez Ulloa, G. H.; Rivasplata Mendoza, A. I.; Tonasse, M. D.
Fonte: Amer Physical Soc Publicador: Amer Physical Soc
Tipo: Artigo de Revista Científica Formato: 9
Português
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Processo FAPESP: 09/02272-2; present an analysis of production and signature of neutral Higgs boson (H-2(0)) on the version of the 3-3-1 model containing heavy leptons at the Large Hadron Collider. We studied the possibility to identify it using the respective branching ratios. Cross section are given for the collider energy, root S = 14 TeV. Event rates and significances are discussed for two possible values of integrated luminosity, 300 fb(-1) and 3000 fb(-1).

O uso do software de edição áudio Audacity 2.0.5: aprendizagens decorrentes da sua utilização

Simões, Carlos Vicente Roupeta
Fonte: Universidade Nova de Lisboa Publicador: Universidade Nova de Lisboa
Tipo: Dissertação de Mestrado
Publicado em /10/2014 Português
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Contém CD com áudio como anexo; O presente documento é resultado e reflexo da Prática de Ensino Supervisionada (PES) na Escola sede do Agrupamento de Escolas Pedro Jacques de Magalhães, em Alverca do Ribatejo, durante o ano letivo de 2013-2014 sob a orientação do Professor Paulo Cairrão. Os relatos, e respetivas reflexões criticas são referentes ao acompanhamento da turma F do 5.º ano, das turmas G, F e H do 7.º ano de escolaridade, assim como aprendizagens e reflexões sobre o acompanhamento e participação no Clube de Teatro. É apresentado em três partes: na Parte 1 aponto assuntos respeitantes à PES, onde refiro aulas observadas e lecionadas e uma breve incursão bibliográfica sobre as atividades extracurriculares, onde o Clube de Teatro se insere; na Parte 2 apresento um panorama geral do modo como se ensina oficialmente Música em Portugal; na Parte 3 explano o Projeto de Investigação que denominei de “O uso do software de edição áudio Audacity 2.0.5: aprendizagens decorrentes da sua utilização”. Justifico esta temática por a achar pertinente, próxima e apelativa aos alunos e pela inexistência de trabalhos académicos que apresentem provas de aprendizagens musicais decorrentes da manipulação sonora...

Um estudo de caso do diagnose virtual na web 2.0.

MASSRUHÁ, S. M. F. S.; LIMA, H. P. de; EVANGELISTA, S. R. M.; ASSAD, E. D.; PINTO, G. E. M.
Fonte: In: CONGRESSO BRASILEIRO DE AGROINFORMÁTICA, 7., 2009, Viçosa, MG. Anais... Viçosa, MG: UFV, 2009. Publicador: In: CONGRESSO BRASILEIRO DE AGROINFORMÁTICA, 7., 2009, Viçosa, MG. Anais... Viçosa, MG: UFV, 2009.
Tipo: Artigo em anais de congresso (ALICE) Formato: Não paginado.
Português
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Neste trabalho são apresentados os resultados obtidos na integração do módulo produtor do Diagnose Virtual ao portal WebAgritec visando garantir a interoperabilidade do mesmo. O projeto WebAgritec tem como objetivo desenvolver uma infra-estrutura, concretizada na forma de um website, que integrará vários sistemas desenvolvidos na Embrapa Informática Agropecuária. Um dos principais requisitos deste projeto é interface baseada nos conceitos de interatividade da Web 2.0. Além desse conceito, tecnologias e padrões de projeto próprios para o desenvolvimento de aplicações web e plataformas, bem como comunicação entre seus componentes são investigados. Outros requisitos não funcionais como desempenho e escalabilidade também devem ser analisados.; 2009; SBIAgro 2009.

About the difference in the quadrupole splitting of water between cationic and anionic nematic lyotropic liquid crystals. H-2-NMR and molecular dynamics study

Ahumada, H.; Montecino, R.; Martínez, R.; Araya Maturana, R.; Weiss López, B. E.
Fonte: SOCIEDAD CHILENA DE QUIMICA Publicador: SOCIEDAD CHILENA DE QUIMICA
Tipo: Artículo de Revista
Português
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Indexación: Scielo; Deuterium quadrupole splittings, of deuterated water, Deltav, in anionic discotic nematic lyomesophases are always much larger than in cationic mesophases. To explore the possible origins of this difference, Deltav and T-1 relaxation times of HDO (H2O 0.2% D2O) and decanol (DeOH 14% alpha-d(2)), in solutions of cationic and anionic discotic lyotropic nernatic liquid crystals, were measured using H-2-NMR. The four component mesophases were prepared based on tetradecyltrimethylammonium bromide, (TTAB/DeOH/NaBr/H2O), and cesium N-dodecanoyl-L-alaninate, (CsDAla/DeOH/KCI/H2O), amphiphiles with cationic and anionic head-groups, respectively. For a better understanding of the experimental results, 15 ns molecular dynamics (MD) trajectories of both systems were calculated. The results suggest that the large difference observed in the quadrupole splittings of the solvent can be mainly attributed to a preferential orientation of the water molecules, induced by the strong electric field generated by the electrical bilayer formed at the interface of the anionic mesophase. Restrictions to solvent reorientational dynamics or differences in the thickness of the interface do not seem to play a significant role to explain the observed difference.

Método de análise de conteúdo para estruturar um modelo de boas práticas sociais na biblioteca pública 2.0

Alvim, Luísa; Casa de Camilo-Museu. Centro de Estudos; Calixto, José António; Biblioteca Pública de Évora CIDEHUS-UÉ (Centro Interdisciplinar de História, Culturas e Sociedades da Universidade de Évora) FCSH-UNL (Faculdade de Ciências Sociais e H
Fonte: Actas do Congresso Nacional de Bibliotecários, Arquivistas e Documentalistas Publicador: Actas do Congresso Nacional de Bibliotecários, Arquivistas e Documentalistas
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; article Formato: application/pdf
Publicado em 18/10/2012 Português
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Esta comunicação apresenta uma reflexão teórica e uma revisão crítica sobre a questão de como conceber um modelo de análise que permita observar, recolher e quantificar dados a observar nas páginas do Facebook de bibliotecas públicas sobre o desempenho social das mesmas e a contribuição dos utilizadores, para que se crie uma estrutura que defina boas práticas na biblioteca pública 2.0. A revisão de literatura sobre o tópico métodos de análise de conteúdo para a construção de um modelo original para esta investigação é o foco central deste artigo. O trabalho futuro visa aprofundar a questão da função social da biblioteca pública, para discernir quais os constructos sociais que definem esta missão e quais os que deverão ser selecionados para o modelo de análise. A biblioteca pública desempenha um papel social importante no espaço público físico e online permitindo o encontro e o relacionamento social entre pessoas e comunidades, possibilitando aos seus utilizadores reais e virtuais a constituição de uma experiência social que poderá ser positiva. A oferta de serviços pelas tecnologias de informação e comunicação são a nova porta de entrada a todos os utilizadores, alargada a uma comunidade mais ampla e enriquecida pelas capacidades da Web social. Este estudo aborda uma breve revisão bibliográfica sobre métodos de análise e consequentes modelos CSCL...

Conformational dynamics of substituted N-acetyl-N-phenylbenzylamines. H-1-DNMR and AM1-MO study

Jullian, Carolina; Araya Maturana, Ramiro Juan; Pessoa, H.; Valderrama, J.; Saitz B., C.; Weiss López, Boris Enrique
Fonte: SOCIEDAD CHILENA DE QUIMICA Publicador: SOCIEDAD CHILENA DE QUIMICA
Tipo: Artículo de revista
Português
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Activation parameters for the rotation around the methylene-nitrogen single bond found in a series of four 2,2'-disubstituted N-acetyl-N-phenylbenzylamines, dissolved in DMSO-d(6), were measured employing the temperature dependence of the H-1-NMR spectrum lineshape between 340 and 400 K. The results are (I) 2 - [N-acetyl -N- (2-acetamidophenyl) aminomethyl] phenyl acetate DeltaG(not equal) =79.9 +/-2.0 kJ/mol (370K), DeltaH(not equal) =96.2 +/-6.0 kJ/mol and DeltaS(not equal) =+45 +/- 20 J/Kmol; (II) 2 [N - acetyl - N - (2-acetyioxybenzyl)amino]benzylacetate DeltaG(not equal) =82.0 +/-2.0 kJ/mol (370K), DeltaH(not equal) =79.1 +/-6.0 kcal/mol and DeltaS(not equal) =8 +/- 20 J/Kmol; (III) 2 - [N - Acetyl - N - (2-nitrobenzyl)amino]benzylacetate DeltaG(not equal) =80.8 +/-2.0 kJ/mol (380K), DeltaH(not equal) =60.7 +/-6.0 kcal/mol and DeltaS(not equal) =53 +/- 20 J/Kmol; (IV) 2-[N-Acetyl-N-(2-acetyloxybenzyl)amino]phenylacetate DeltaG(not equal) =77.0 +/-2.0 kJ/mol (370K), DeltaH(not equal) =65.3 +/-6.0 kJ/mol and DeltaS(not equal) =-32 +/- 20 J/Kmol. Substitution at positions 2 and 2' with bulky groups appears to be essential to freeze the gauche structure at room temperature and consequently, the main contribution to the barrier arises from the steric hindrance between these two groups. Structure I shows an anomalous behavior...

About the difference in the quadrupole splitting of water between cationic and anionic nematic lyotropic liquid crystals. H-2-NMR and molecular dynamics study

Montecinos, R.; Weiss López, Boris Enrique; Martínez, R.; Araya Maturana, Ramiro Juan; Ahumada, H.
Fonte: SOCIEDAD CHILENA DE QUIMICA Publicador: SOCIEDAD CHILENA DE QUIMICA
Tipo: Artículo de revista
Português
Relevância na Pesquisa
76.398984%
Deuterium quadrupole splittings, of deuterated water, Deltav, in anionic discotic nematic lyomesophases are always much larger than in cationic mesophases. To explore the possible origins of this difference, Deltav and T-1 relaxation times of HDO (H2O 0.2% D2O) and decanol (DeOH 14% alpha-d(2)), in solutions of cationic and anionic discotic lyotropic nernatic liquid crystals, were measured using H-2-NMR. The four component mesophases were prepared based on tetradecyltrimethylammonium bromide, (TTAB/DeOH/NaBr/H2O), and cesium N-dodecanoyl-L-alaninate, (CsDAla/DeOH/KCI/H2O), amphiphiles with cationic and anionic head-groups, respectively. For a better understanding of the experimental results, 15 ns molecular dynamics (MD) trajectories of both systems were calculated. The results suggest that the large difference observed in the quadrupole splittings of the solvent can be mainly attributed to a preferential orientation of the water molecules, induced by the strong electric field generated by the electrical bilayer formed at the interface of the anionic mesophase. Restrictions to solvent reorientational dynamics or differences in the thickness of the interface do not seem to play a significant role to explain the observed difference.

H_2 Pure Rotational Lines in the Orion Bar

Allers, K. N.; Jaffe, D. T.; Lacy, J. H.; Draine, B. T.; Richter, M. J.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 31/05/2005 Português
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Using the Texas Echelon Cross Echelle Spectrograph (TEXES) we mapped emission in the H_2 v = 0-0 S(1) and S(2) lines toward the Orion Bar PDR at 2" resolution. We also observed H_2 v = 0-0 S(4) at selected points toward the front of the PDR. Our maps cover a 12" by 40" region of the bar where H_2 ro-vibrational lines are bright. The distributions of H_2 0-0 S(1), 0-0 S(2), and 1-0 S(1) line emission agree in remarkable detail. The high spatial resolution (0.002 pc) of our observations allows us to probe the distribution of warm gas in the Orion Bar to a distance approaching the scale length for FUV photon absorption. We use these new observational results to set parameters for the PDR models described in a companion paper (Draine et al. 2005, in prep). The best-fit model can account for the separation of the H_2 emission from the ionization front and the intensities of the ground state rotational lines as well as the 1-0 S(1) and 2-1 S(1) lines. This model requires significant adjustments to the commonly used values for the dust UV attenuation cross section and the photoelectric heating rate.; Comment: 35 pages, 6 figures ApJ, accepted

SUSY and the decay H_2^0-->gg

König, Heinz
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 14/06/1996 Português
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In this talk I present a detailed SUSY QCD calculation of the decay rate of the lightest Higgs boson $H^0_2$\ into two gluons, where all quarks and scalar quarks are taken within the relevant loop diagrams. I include the mixing of all the three generations of the scalar partners of the left and right handed quarks and show that their contribution is comparable to the quark contribution in the MSSM for small values of the soft SUSY breaking parameter $m_S$. Furthermore in the MSSM the contribution from the bottom quark becomes as large as the top quark contribution for large $\tan\beta$\ and large Higgs masses. As a result, the two gluon decay rate of $H_2^0$\ is much larger than the two gluon decay rate of an equal mass standard model Higgs boson. I further compare the decay mode of $H^0_2\rightarrow gg$\ to the similar decay modes of $H^0_2\rightarrow c\overline c$\ including one loop QCD corrections and show that in some cases $\Gamma(H^0_2\rightarrow gg)$\ is even higher than $\Gamma(H^0_2\rightarrow c\overline c)$.; Comment: 7 pages (plain TeX), 6 figures (not included, available under request), talk presented at the MRST-96 conference at University of Toronto, May 9-10, 1996

On the Tate and Mumford-Tate conjectures in codimension one for varieties with h^{2,0}=1

Moonen, Ben
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
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We prove the Tate conjecture for divisor classes and the Mumford-Tate conjecture for the cohomology in degree 2 for varieties with $h^{2,0}=1$ over a finitely generated field of characteristic 0, under a mild assumption on their moduli. As an application of this general result, we prove the Tate and Mumford-Tate conjectures for some classes of algebraic surfaces with $p_g=1$.; Comment: Minor corrections, improvements to the exposition. 44 pages, 1 figure

ISO-SWS Observations of OMC-1: H_2 and Fine Structure Lines

Rosenthal, Dirk; Bertoldi, Frank; Drapatz, Siegfried
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 24/02/2000 Português
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Using the Short-Wavelength-Spectrometer on the Infrared Space Observatory (ISO), we obtained near- and mid-infrared spectra toward the brightest H_2 emission peak of the Orion OMC-1 outflow. A wealth of emission and absorption features were detected, dominated by 56 H_2 ro-vibrational and pure rotational lines reaching from H_2 0-0 S(1) to 0-0 S(25). The spectra also show a number of H I recombination lines, atomic and ionic fine structure lines, and molecular lines of CO and H_2O. Between 6 and 12 mu the emission is dominated by PAH features. The H_2 level column density distribution shows no signs of fluorescent excitation or a deviation from an ortho-to-para ratio of three. It shows an excitation temperature which increases from about 600 K for the lowest rotational and vibrational levels to about 3200 K at level energies E(v,J)/k > 14 000 K. No single steady state shock model can reproduce the observed H_2 excitation. The higher energy H_2 levels may be excited either thermally in non-dissociative J-shocks, through non-thermal collisions between fast ions and molecules with H_2 in C-shocks, or they are pumped by newly formed H_2 molecules. The highest rotational levels may be populated by yet another mechanism, such as the gas phase formation of H_2 through H^-.; Comment: 22 pages...

D/H in a new Lyman limit quasar absorption system at z=3.256 towards PKS1937-1009

Crighton, N. H. M.; Webb, J. K.; Ortiz-Gil, A.; Fernandez-Soto, A.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
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56.80394%
We have identified a new Lyman limit absorption system towards PKS1937-1009, with log N(HI)=18.25 +/- 0.02 at z=3.256. It is suitable for measuring D/H, and we find a 68.3% confidence range for D/H of 1.6^{+0.25}_{-0.30} \times 10^{-5}, and a 95.4% range of 1.6^{+0.5}_{-0.4} \times 10^{-5}. The metallicity of the cloud where D/H was measured is low, [Si/H] = -2.0 +/- 0.5. At these metallicities we expect that D/H will be close to the primordial value. Our D/H disagrees at a level of 99.4% with the predicted D/H using the baryon density calculated from the cosmic background radiation measured by WMAP, 2.60^{+0.19}_{-0.17} \times 10^{-5}. Our result also exacerbates the scatter in D/H values around the mean primordial D/H.; Comment: 13 pages, accepted by MNRAS. Version 2: corrected typos. Version 3: Final accepted version. Includes new section comparing this result to other QSO D/H results

Detection of OH$^+$ and H$_2$O$^+$ towards Orion~KL

Gupta, H.; Rimmer, P.; Pearson, J. C.; Yu, S.; Herbst, E.; Harada, N.; Bergin, E. A.; Neufeld, D. A.; Melnick, G. J.; Bachiller, R.; Baechtold, W.; Bell, T. A.; Blake, G. A.; Caux, E.; Ceccarelli, C.; Cernicharo, J.; Chattopadhyay, G.; Comito, C.; Cabrit,
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 08/09/2010 Português
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We report observations of the reactive molecular ions OH$^+$, H$_2$O$^+$, and H$_3$O$^+$ towards Orion KL with Herschel/HIFI. All three $N=1-0$ fine-structure transitions of OH$^+$ at 909, 971, and 1033GHz and both fine-structure components of the doublet {\it ortho}-H$_2$O$^+$ $1_{11}-0_{00}$ transition at 1115 and 1139GHz were detected; an upper limit was obtained for H$_3$O$^+$. OH$^+$ and H$_2$O$^+$ are observed purely in absorption, showing a narrow component at the source velocity of 9 kms$^{-1}$, and a broad blueshifted absorption similar to that reported recently for HF and {\it para}-H$_{2}^{18}$O, and attributed to the low velocity outflow of Orion KL. We estimate column densities of OH$^+$ and H$_2$O$^+$ for the 9 km s$^{-1}$ component of $9 \pm 3 \times 10^{12}$cm$^{-2}$ and $7 \pm 2 \times 10^{12}$cm$^{-2}$, and those in the outflow of $1.9 \pm 0.7 \times 10^{13}$cm$^{-2}$ and $1.0 \pm 0.3 \times 10^{13}$cm$^{-2}$. Upper limits of $2.4\times 10^{12}$cm$^{-2}$ and $8.7\times 10^{12}$cm$^{-2}$ were derived for the column densities of {\it ortho} and {\it para}-H$_3$O$^+$ from transitions near 985 and 1657GHz. The column densities of the three ions are up to an order of magnitude lower than those obtained from recent observations of W31C and W49N. The comparatively low column densities may be explained by a higher gas density despite the assumption of a very high ionization rate.; Comment: 5 pages...

First spectrally-resolved H$_2$ observations towards HH 54 / Low H$_2$O abundance in shocks

Santangelo, G.; Antoniucci, S.; Nisini, B.; Codella, C.; Bjerkeli, P.; Giannini, T.; Lorenzani, A.; Lundin, L. K.; Cabrit, S.; Calzoletti, L.; Liseau, R.; Neufeld, D.; Tafalla, M.; van Dishoeck, E. F.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 09/09/2014 Português
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Context: Herschel observations suggest that the H$_2$O distribution in outflows from low-mass stars resembles the H$_2$ emission. It is still unclear which of the different excitation components that characterise the mid- and near-IR H$_2$ distribution is associated with H$_2$O. Aim: The aim is to spectrally resolve the different excitation components observed in the H$_2$ emission. This will allow us to identify the H$_2$ counterpart associated with H$_2$O and finally derive directly an H$_2$O abundance estimate with respect to H$_2$. Methods: We present new high spectral resolution observations of H$_2$ 0-0 S(4), 0-0 S(9), and 1-0 S(1) towards HH 54, a bright nearby shock region in the southern sky. In addition, new Herschel-HIFI H$_2$O (2$_{12}$$-$1$_{01}$) observations at 1670~GHz are presented. Results: Our observations show for the first time a clear separation in velocity of the different H$_2$ lines: the 0-0 S(4) line at the lowest excitation peaks at $-$7~km~s$^{-1}$, while the more excited 0-0 S(9) and 1-0 S(1) lines peak at $-$15~km~s$^{-1}$. H$_2$O and high-$J$ CO appear to be associated with the H$_2$ 0-0 S(4) emission, which traces a gas component with a temperature of 700$-$1000 K. The H$_2$O abundance with respect to H$_2$ 0-0 S(4) is estimated to be $X$(H$_2$O)$<$1.4$\times$10$^{-5}$ in the shocked gas over an area of 13$^{\prime\prime}$. Conclusions: We resolve two distinct gas components associated with the HH 54 shock region at different velocities and excitations. This allows us to constrain the temperature of the H$_2$O emitting gas ($\leq$1000 K) and to derive correct estimates of H$_2$O abundance in the shocked gas...

Broad-band photometric colors and effective temperature calibrations for late-type giants. II. Z<0.02

Kucinskas, A.; Hauschildt, P. H.; Brott, I.; Vansevicius, V.; Lindegren, L.; Tanabe, T.; Allard, F.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 16/03/2006 Português
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(Abridged) We investigate the effects of metallicity on the broad-band photometric colors of late-type giants, and make a comparison of synthetic colors with observed photometric properties of late-type giants over a wide range of effective temperatures (T_eff=3500-4800 K) and gravities (log g=0.0-2.5), at [M/H]=-1.0 and -2.0. The influence of metallicity on the synthetic photometric colors is generally small at effective temperatures above \~3800 K, but the effects grow larger at lower T_eff, due to the changing efficiency of molecule formation which reduces molecular opacities at lower [M/H]. To make a detailed comparison of the synthetic and observed photometric colors of late type giants in the T_eff--color and color--color planes, we derive a set of new T_eff--log g--color relations based on synthetic photometric colors, at [M/H]=-0.5, -1.0, -1.5, and -2.0. While differences between the new T_eff--color relations and those available from the literature are typically well within ~100 K, effective temperatures predicted by the scales based on synthetic colors tend to be slightly higher than those resulting from the T_eff--color relations based on observations, with the offsets up to ~100 K. This is clearly seen both at [M/H]=-1.0 and -2.0...

On the Possibility of Observing the Double Emission Line Feature of H$_2$ and HD from Primordial Molecular Cloud Cores

Kamaya, H.; Silk, J.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
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We study the prospects for observing H$_2$ and HD emission during the assembly of primordial molecular cloud cores. The primordial molecular cloud cores, which resemble those at the present epoch, can emerge around $1+z \sim 20$ according to recent numerical simulations. A core typically contracts to form the first generation of stars and the contracting core emits H$_2$ and HD line radiation. These lines show a double peak feature. The higher peak is the H$_2$ line of the $J=2-0$ (v=0) rotational transition, and the lower peak is the HD line of the $J=4-3$ (v=0) rotational transition. The ratio of the peaks is about 20, this value characterising the emission from primordial galaxies. The expected emission flux at the redshift of $1+z \sim 20$ (e.g. $\Omega_m = 0.3$ and $\Omega_\Lambda =0.7$), in the $J=2-0$ (v=0) line of H$_2$ occurs at a rate $\sim 2 \times 10^{-7}$ Jy, and in the $J=4-3$ (v=0) line of HD at a rate $\sim 4 \times 10^{-9}$ Jy. The former has a frequency of 5.33179$\times 10^{11}$ Hz and the latter is at 5.33388 $\times 10^{11}$Hz, respectively. Since the frequency resolution of ALMA is about 40 kHz, the double peak is resolvable. While an individual object is not observable even by ALMA, the expected assembly of primordial star clusters on subgalactic scales can result in fluxes at the 2000-50 $\mu$Jy level. These are marginally observable. The first peak of H$_2$ is produced when the core gas cools due to HD cooling...

Search for the Higgs Boson $H_2^0$ at LHC in 3-3-1 Model

Montalvo, J. E. Cieza; Ramírez, R. J. Gil; Ulloa, G. H. Ramírez; Mendoza, A. I. Rivasplata
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
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76.402656%
We present an analysis of production and signature of neutral Higgs boson ($H_{2}^{0}$) on the version of the 3-3-1 model containing heavy leptons at the Large Hadron Collider. We studied the possibility to identify it using the respective branching ratios. Cross section are given for the collider energy, $\sqrt{s} =$ 14 TeV. Event rates and significances are discussed for two possible values of integrated luminosity, 300 fb$^{-1}$ and 3000 fb$^{-1}$.; Comment: 17 pages 7 figures. arXiv admin note: substantial text overlap with arXiv:1205.4042

Detection of Powerful Mid-IR H_2 Emission in the Bridge between the Taffy Galaxies

Peterson, B. W.; Appleton, P. N.; Helou, G.; Guillard, P.; Jarrett, T. H.; Cluver, M. E.; Ogle, P.; Struck, C.; Boulanger, F.
Fonte: American Astronomical Society Publicador: American Astronomical Society
Tipo: Article; PeerReviewed Formato: application/pdf
Publicado em 20/05/2012 Português
Relevância na Pesquisa
56.81589%
We report the detection of strong, resolved emission from warm H_2 in the Taffy galaxies and bridge. Relative to the continuum and faint polyclic aromatic hydrocarbon (PAH) emission, the H_2 emission is the strongest in the connecting bridge, approaching L(H_2)/L(PAH 8 μm) = 0.1 between the two galaxies, where the purely rotational lines of H_2 dominate the mid-infrared spectrum in a way very reminiscent of the group-wide shock in the interacting group Stephan's Quintet (SQ). The surface brightness in the 0-0 S(0) and S(1) H_2 lines in the bridge is more than twice that observed at the center of the SQ shock. We observe a warm H2 mass of 4.2 × 10^8 M_☉ in the bridge, but taking into account the unobserved bridge area, the total warm mass is likely to be twice this value. We use excitation diagrams to characterize the warm molecular gas, finding an average surface mass of ~5 × 10^6 M_☉ kpc^(–2) and typical excitation temperatures of 150-175 K. H_2 emission is also seen in the galaxy disks, although there the emission is more consistent with normal star-forming galaxies. We investigate several possible heating mechanisms for the bridge gas but favor the conversion of kinetic energy from the head-on collision via turbulence and shocks as the main heating source. Since the cooling time for the warm H_2 is short (~5000 yr)...