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Fitoterapia aplicada à prevenção e tratamento de infecções urinárias

Teixeira, Ana Catarina de Jesus
Fonte: [s.n.] Publicador: [s.n.]
Tipo: Dissertação de Mestrado
Publicado em //2012 POR
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16.79%
Projeto de Pós-Graduação/Dissertação apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Mestre em Ciências Farmacêuticas; A crescente insatisfação referente à ineficácia de algumas terapêuticas convencionais, o grande número de efeitos secundários associados a fármacos de síntese química, bem como o desenvolvimento científico e técnico, estimularam o mercado dos medicamentos e produtos à base de plantas e consequentemente, verifica-se um aumento nos pedidos de orientação farmacêutica e clínica, para a qual os profissionais de saúde devem estar capacitados. A informação transmitida aos consumidores deve ser sustentada no conhecimento científico, através de estudos clínicos. Só promovendo o uso racional de medicamentos à base de plantas, se conseguirá enquadrar devidamente a Fitoterapia na terapêutica convencional. O presente trabalho de revisão bibliográfica aborda vários aspectos relacionados com o uso racional de plantas medicinais com fins preventivos e/ou terapêuticos em infecções urinárias, em associação ou não com fármacos de síntese química (por exemplo, sumo de arando americano e antibióticos β-lactâmicos), fundamentando-os com estudos clínicos actualmente disponíveis. São inúmeras as plantas que podem ser usadas com fins terapêuticos no âmbito das infecções urinárias. Algumas delas credenciaram-se pelo seu uso tradicional ao longo dos séculos. Outras...

Assessment of strategies to increase chondrocyte viability in cryopreserved human osteochondral allografts: evaluation of the glycosylated hydroquinone, arbutin

Rosa, Susana Carvalho; Gonçalves, Juliana; Judas, Fernando; Lopes, Celeste; Mendes, Alexandrina Ferreira
Fonte: Osteoarthritis Research Society International. Published by Elsevier Ltd. Publicador: Osteoarthritis Research Society International. Published by Elsevier Ltd.
Tipo: Artigo de Revista Científica
ENG
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Objective: Allogeneic cartilage is used to repair damaged areas of articular cartilage, requiring the presence of living chondrocytes. So far, no preservation method can effectively meet that purpose. Identification of more effective cryoprotective agents (CPAs) can contribute to this goal. The aim of this study was to determine whether the glycosylated hydroquinone, arbutin, alone or in combination with low concentrations of other CPAs, has cryoprotective properties towards human articular cartilage. Material and methods: Human tibial plateaus were procured from multi-organ donors, with the approval of the Ethics Committee of the University Hospital of Coimbra. The tibial plateaus were treated with or without arbutin (50 or 100 mM), alone or in combination with various concentrations of dimethyl sulfoxide (DMSO) and glycerol, for 0.5e1.5 h/37 C, then frozen at 20 C and 24 h later transferred to a biofreezer at 80 C. Two to 3 months later, thawing was achieved by immersion in cell culture medium at 37 C/1 h. Chondrocyte viability was assessed before and after freezeethawing using a colorimetric assay based on the cell’s metabolic activity and fluorescent dyes to evaluate cell membrane integrity. Results: Before freezing, chondrocyte metabolic activity was identical in all the conditions tested. After freezeethawing...

Ação antioxidante de extratos de especiarias e suas misturas binárias e ternárias sobre a estabilidade oxidativa de óleo de soja; Antioxidant activity of spices extracts and their binary and ternary mixtures on soybean oil oxidative stability

Shimano, Marilis Yoshie Hayashi
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 01/10/2012 PT
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A oxidação de lipídeos produz compostos indesejáveis que alteram as características organolépticas de alimentos lipídicos e reduzem a qualidade nutricional. Nas indústrias alimentícia, cosmética e farmacêutica são adicionados antioxidantes sintéticos para retardar ou prevenir a deterioração lipídica. Devido aos estudos sobre a possível toxicidade dos antioxidantes sintéticos e ao apelo por compostos ativos naturais, o uso de antioxidantes naturais presentes em ervas e especiarias representa uma alternativa promissora. No presente trabalho foram estudadas as condições de obtenção de extratos hidroalcoólicos de especiarias e sua aplicação em óleo de soja refinado em teste acelerado. O estudo do efeito da temperatura e do grau de hidratação do etanol sobre o teor de compostos fenólicos totais dos extratos de alecrim, orégano, sálvia e tomilho foi realizado com aplicação de planejamento experimental e metodologia de superfícies de resposta. As condições para uma extração eficiente dos compostos fenólicos de alecrim e tomilho desidratados foram o uso de etanol 50% (v/v) e temperatura entre 45 a 50°C. Extrato de sálvia com maiores concentrações em fenólicos totais foram obtidos com etanol 50% (v/v) em uma faixa de temperatura de 57...

Estudo químico de chás brasileiros

Andrade, Fábio Donisete Pezzuto de
Fonte: Universidade Estadual Paulista (UNESP) Publicador: Universidade Estadual Paulista (UNESP)
Tipo: Tese de Doutorado Formato: ix, 110 f. : il. + anexo
POR
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Pós-graduação em Química - IQ; Neste trabalho apresentamos o estudo químico de plantas que são popularmente utilizadas na forma de infusão. Como parte de nosso projeto, estudamos espécies usadas no tratamento de úlceras gástricas: Quassia amara (Simaroubaceae), Alchornea castaneifolia (Euphorbiaceae), Curatella americana (Dilleniaceae) e Hancornea speciosa (Apocynaceae). Os extratos foram avaliados farmacológicamente em diferente modelos indutores de úlcera para avaliar suas atividades. Os extratos ativos foram fracionados por técnicas cromatograficas e as substâncias identificadas por métodos espectrométricos. Em Quassia amara foram identificados principalmente esteróides e quassinóides; em C. americana foram identificados taninos, catequinas, terpenos e ácidos fenólicos; em A. castaneifolia foram encontrados flavonóides glicosilados e em H. speciosa foram identificados a catequina e o ácido clorogênico. Os extratos contendo essas substâncias apresentam atividade antiúlcera comprovada dando suporte para o uso das plantas pela população. Apresentamos também o estudo fitoquímico de Ilex amara e Ilex theezans, duas plantas da família Aquifoliaceae...

Aloenxertos criopreservados no tratamento de defeitos osteocartilagíneos

Judas, F; Mendes, AF
Fonte: Banco de Tecidos dos HUC, Clínica Universitária de Ortopedia dos HUC; Faculdade de Farmácia e Grupo de Imunologia Celular do Centro de Neurociências e Biologia Celular, Universidade de Coimbra Publicador: Banco de Tecidos dos HUC, Clínica Universitária de Ortopedia dos HUC; Faculdade de Farmácia e Grupo de Imunologia Celular do Centro de Neurociências e Biologia Celular, Universidade de Coimbra
Tipo: Relatório
Publicado em //2009 POR
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A reparação cirúrgica dos defeitos da cartilagem articular representa uma das situações mais difíceis de tratar em Ortopedia. Os aloenxertos osteocartilagíneos devem ser reservados para a reconstrução de defeitos significativos envolvendo cartilagem e osso (> 3 cm de diâmetro e 1 cm de profundidade), isto é, nas lesões demasiado extensas para serem corrigidas através de outras técnicas. Os aloenxertos osteocartilagíneos criopreservados apresentam vantagens em relação aos frescos, que incluem uma maior segurança microbiológica, menor capacidade imunogénica ligada ao tecido ósseo e estão disponíveis em maior número. No entanto, os aloenxertos osteocartilagíneos frescos mantêm uma maior viabilidade condrocitária e, por isso, oferecem um melhor desempenho clínico. Embora permita recuperar um maior número de condrócitos vivos, a utilização de crioprotectores está ainda longe de originar a protecção completa e eficaz de todos os condrócitos presentes na cartilagem articular, o que compromete significativamente o desempenho clínico a médio ou a longo termo dos aloenxertos osteocartilagíneos criopreservados. A combinação de um potente agente crioprotector como parece ser a arbutina, com meios mecânicos capazes de exercer uma pressão adequada poderá ser a chave para se alcançar uma percentagem significativa de condrócitos vivos após o processo de descongelação da cartilagem criopreservada e...

488 The Effect of Specific Immunotherapy on the Clinical Response in Patients with Grass-pollen Induced Rhinoconjunctivitis

Arsovski, Zoran; Kaeva, Biserka Jovkovska; Gavrilovski, Miroslav; Stefanovski, Tome; Pejkovska, Sava; Arbutina, Suzana; Ismaili, Irfan; Caparoska, Tatjana; Dokic, Dejan
Fonte: World Allergy Organization Journal Publicador: World Allergy Organization Journal
Tipo: Artigo de Revista Científica
Publicado em 17/02/2012 EN
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Desenvolvimento de metodologias para identificação de proteínas e metabólitos durante o desenvolvimento de frutos de café (Coffea arabica L.)

Fonte: UNIVERSIDADE FEDERAL DE LAVRAS; PPBV - Programa de Pós-graduação em Biotecnologia Vegetal; UFLA; BRASIL Publicador: UNIVERSIDADE FEDERAL DE LAVRAS; PPBV - Programa de Pós-graduação em Biotecnologia Vegetal; UFLA; BRASIL
Tipo: Tese de Doutorado
PT_BR
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Tese apresentada à Universidade Federal de Lavras, como parte das exigências do Programa de Pós-Graduação em Biotecnologia Vegetal, área de concentração em Biotecnologia Vegetal, para a obtenção do título de Doutor.; Financiadora de Estudos e Projetos (FINEP); Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA)

Screening of polyphenolic compounds in Piper trioicum (Roxb.) extracts

Sathis Kumar, Dinakaran; Harani, Avasarala; David, Banji; Veena, Mandarapu
Fonte: Universidad de Granada, Facultad de Farmacia Publicador: Universidad de Granada, Facultad de Farmacia
Tipo: Artigo de Revista Científica
ENG
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We are grateful to the Management, Nalanda College of Pharmacy, Nalgonda, Andhra Pradesh for their valuable support.; Aims: Present study aims to reveal the polyphenol content in Piper trioicum (Roxb.) extracts. Materials and methods: In the present study, the phenolic content of the ethanol and water extracts of Piper trioicum (Roxb.) plants was determined by chromatography techniques like Thin layer chromatography, high performance thin layer Chromatography, high performance liquid chromatography and Gas chromatography with Mass spectrometric detection. Total phenol was determined by UV method. Results: All the results of analytical methods were compared with standard phenolic compounds. The ethanol extract contained maximum total phenolic content (2.323mg GAE/g) than the water extract. 13 compounds identified by chromatography techniques. The results suggested Arbutin, quercetin, caffeic acid, Ferulic acid, chlorogenic acid, Gallic acid and its derivatives may be present in ethanolic and water extracts of Piper trioicum. Conclusions: The water and ethanol could extract the highest concentration of polyphenols from the Piper trioicum (Roxb) plant; these extracts may have a good pharmacological potency due to the presence of polyphenols compounds.; Objetivo: El presente estudio tiene como objetivo revelar el contenido de polifenoles en extractos de Piper trioicum ( Roxb. ). Materiales y m??todos: El contenido de fenoles totales en los extractos etan??licos y acuosos de Piper trioicum ( Roxb. ) se determin?? mediante t??cnicas cromatograf??as...

On calibration of some distance scales in astrophysics

Vukotic, B.; Jurkovic, M.; Urosevic, D.; Arbutina, B.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
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We present a method for distance calibration without using standard fitting procedures. Instead we use random resampling to reconstruct the probability density function (PDF) of calibration data points in the fitting plane. The resulting PDF is then used to estimate distance-related properties. The method is applied to samples of radio surface brightness to diameter (\Sigma-D) data for the Galactic supernova remnants (SNRs) and planetary nebulae (PNe), and period-luminosity (PL) data for the Large Magellanic Cloud (LMC) fundamental mode classical Cepheids. We argue that resulting density maps can provide more accurate and more reliable calibrations than those obtained by standard linear fitting procedures. For the selected sample of the Galactic SNRs, the presented PDF method of distance calibration results in a smaller average distance fractional error of up to $\approx 16$ percentage points. Similarly, the fractional error is smaller for up to $\approx 8$ and $\approx 0.5$ percentage points, for the samples of Galactic PNe and LMC Cepheids, respectively. In addition, we provide a PDF-based calibration data for each of the samples.; Comment: 11 pages, 3 figures, corrected for mistakenly considering working data as absolute instead of apparent magnitude...

Optical Observations of M81 Galaxy Group in Narrow Band [SII] and H_alpha Filters: Holmberg IX

Arbutina, B.; Ilic, D.; Stavrev, K.; Urosevic, D.; Vukotic, B.; Onic, D.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 26/12/2009
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We present observations of the nearby tidal dwarf galaxy Holmberg IX in M81 galaxy group in narrow band [SII] and H$\alpha$ filters, carried out in March and November 2008 with the 2m RCC telescope at NAO Rozhen, Bulgaria. Our search for resident supernova remnants (identified as sources with enhanced [SII] emission relative to their H$\alpha$ emission) in this galaxy yielded no sources of this kind, besides M&H 10-11 or HoIX X-1. Nevertheless, we found a number of objects with significant H$\alpha$ emission that probably represent uncatalogued HII regions.; Comment: 8 pages, 5 figures

Relativistic Non-Thermal Bremsstrahlung Radiation

Zeković, Vladimir; Arbutina, Bojan; Dobardzić, Aleksandra; Pavlović, Marko
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 21/10/2013
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By applying a method of virtual quanta we derive formulae for relativistic non-thermal bremsstrahlung radiation from relativistic electrons as well as from protons and heavier particles with power-law momentum distribution $N(p)dp = k p^{-q} dp.$ We show that emission which originates from an electron scattering on an ion, represents the most significant component of relativistic non-thermal bremsstrahlung. Radiation from an ion scattering on electron, known as inverse bremsstrahlung, is shown to be negligible in overall non-thermal bremsstrahlung emission. These results arise from theory refinement, where we introduce the dependence of relativistic kinetic energy of an incident particle, upon the energy of scattered photon. In part, it is also a consequence of a different mass of particles and relativistic effects.; Comment: 17 pages, 1 figure, accepted for publication in IJMPA

Optical supernova remnants in nearby galaxies and their influence on star formation rates derived from H$\alpha$ emission

Vucetic, M. M.; Arbutina, B.; Urosevic, D.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
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In this paper we present the most up-to-date list of nearby galaxies with optically detected supernova remnants (SNRs). We discuss the contribution of the H{\alpha} flux from the SNRs to the total H{\alpha} flux and its influence on derived star formation rate (SFR) for 18 galaxies in our sample. We found that the contribution of SNRs' flux to the total H{\alpha} flux is 5 $\pm$ 5 per cent. Due to the observational selection effects, the SNRs contamination of SFRs derived herein represents only a lower limit.; Comment: 18 pages, 4 figures, 3 tables + appendix; accepted by MNRAS

Modified equipartition calculation for supernova remnants

Arbutina, B.; Urosevic, D.; Andjelic, M. M.; Pavlovic, M. Z.; Vukotic, B.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 23/11/2011
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Determination of the magnetic field strength in the interstellar medium is one of the most complex tasks of contemporary astrophysics. We can only estimate the order of magnitude of the magnetic field strength by using a few very limited methods. Besides Zeeman effect and Faraday rotation, the equipartition or the minimum-energy calculation is a widespread method for estimating magnetic field strength and energy contained in the magnetic field and cosmic ray particles by using only the radio synchrotron emission. Despite of its approximate character, it remains a useful tool, especially when there is no other data about the magnetic field in a source. In this paper we give a modified calculation which we think is more appropriate for estimating magnetic field strengths and energetics in supernova remnants (SNRs). Finally, we present calculated estimates of the magnetic field strengths for all Galactic SNRs for which the necessary observational data are available. The web application for calculation of the magnetic field strength of SNRs is available at http://poincare.matf.bg.ac.rs/~arbo/eqp/.; Comment: 19 pages, 4 figures, 1 table, accepted for publication in ApJ; for associated web application, see http://poincare.matf.bg.ac.rs/~arbo/eqp/

Radial Dependence of Extinction in Parent Galaxies of Supernovae

Arbutina, Bojan
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 17/07/2007
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The problem of extinction is the most important issue to be dealt with in the process of obtaining true absolute magnitudes of core-collapse supernovae (SNe). The plane-parallel model which gives absorption dependent on galaxy inclination, widely used in the past, was shown not to describe extinction adequately. We try to apply an alternative model which introduces radial ependence of extinction. A certain trend of dimmer SNe with decreasing radius from the center of a galaxy was found, for a chosen sample of stripped-envelope SNe.; Comment: 4 pages, 1 table, 2 figures, 6th SCSLSA Proc

The Sigma-D Relation for Planetary Nebulae: Preliminary Analysis

Urosevic, D.; Vukotic, B.; Arbutina, B.; Ilic, D.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
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An analysis of the relation between radio surface brightness and diameter, so-called Sigma-D relation, for planetary nebulae (PNe) is presented: i) the theoretical Sigma-D relation for the evolution of bremsstrahlung surface brightness is derived; ii) contrary to the results obtained earlier for the Galactic supernova remnant (SNR) samples, our results show that the updated sample of Galactic PNe does not severely suffer from volume selection effect - Malmquist bias (same as for the extragalactic SNR samples) and; iii) we conclude that the empirical Sigma-D relation for PNe derived in this paper is not useful for valid determination of distances for all observed PNe with unknown distances.; Comment: 4 pages, 2 figures

On the magnetic field evolution in shell-like supernova remnants

Vukotic, Branislav; Arbutina, Bojan; Urosevic, Dejan
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
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In this paper we apply and discuss a method for the determination of the magnetic field ($H$) evolution in supernova remnants (SNRs) from radio luminosity at given frequency $\nu$ to diameter ($L_\mathrm{\nu}-D$) correlation. We assumed that $H$ evolves as $H\propto D^{-\delta}$, where $D$ is the diameter of the remnant. Value $\delta\approx1.2$ is obtained under the equipartition assumption from the equations for revised equipartition calculation (REC) and by using the data sample from the nearby starburst galaxy M82. We try to investigate whether or not SNRs in M82 are in the equipartition state. This is done by comparison of our empirically obtained $\delta$ with the theoretical value expected for the equipartition conditions. Inconsistence between the value obtained for equipartition conditions and adiabatic expansion $(\delta=1.5)$ and the value empirically obtained herein, can be explained mainly by the influence of sensitivity selection effects which tend to flatten the slope of the $L_\nu-D$ relations for extragalactic samples.; Comment: Accepted by RevMexAA to be published on April 2007. 11 pages, 1 figure

The radio surface brightness to diameter relation for galactic supernova remnants: sample selection and robust analysis with various fitting offsets

Pavlovic, M. Z.; Urosevic, D.; Vukotic, B.; Arbutina, B.; Goker, U. D.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 16/10/2012
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In this paper we present new empirical radio surface brightness-to-diameter ({\Sigma} - D) relations for supernova remnants (SNRs) in our Galaxy. We also present new theoretical derivations of the {\Sigma} - D relation based on equipartition or on constant ratio between cosmic rays and magnetic field energy. A new calibration sample of 60 Galactic SNRs with independently determined distances is created. Instead of (standard) vertical regression, used in previous papers, different fitting procedures are applied to the calibration sample in the log {\Sigma} - log D plane. Non-standard regressions are used to satisfy the requirement that values of parameters obtained from the fitting of {\Sigma} - D and D - {\Sigma} relations should be invariant within estimated uncertainties. We impose symmetry between {\Sigma} - D and D - {\Sigma} due to the existence of large scatter in both D and {\Sigma}. Using four fitting methods which treat {\Sigma} and D symmetrically, different {\Sigma} - D slopes {\beta} are obtained for the calibration sample. Monte Carlo simulations verify that the slopes of the empirical {\Sigma} - D relation should be determined by using orthogonal regression, because of its good performance for data sets with severe scatter. The slope derived here ({\beta} = 4.8) is significantly steeper than those derived in previous studies. This new slope is closer to the updated theoretically predicted surface brightness-diameter slope in the radio range for the Sedov phase. We also analyze the empirical {\Sigma} - D relations for SNRs in the dense environment of molecular clouds and for SNRs evolving in lower-density interstellar medium. Applying the new empirical relation to estimate distances of Galactic SNRs results in a dramatically changed distance scale.; Comment: 43 pages...

On the existence of "radio thermally active" Galactic supernova remnants

Onic, D.; Urosevic, D.; Arbutina, B.; Leahy, D.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 07/07/2012
Relevância na Pesquisa
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In this paper, we investigate the possibility of significant production of thermal bremsstrahlung radiation at radio continuum frequencies that could be linked to some Galactic supernova remnants (SNRs). The main targets for this investigation are SNRs expanding in high density environments. There are several indicators of radio thermal bremsstrahlung radiation from SNRs, such as a flattening at higher frequencies and thermal absorption at lower frequencies intrinsic to an SNR. In this work we discuss the radio continuum properties of 3 SNRs that are the best candidates for testing our hypothesis of significant thermal emission. In the case of SNRs IC443 and 3C391, thermal absorption has been previously detected. For IC443, the contribution of thermal emission at 1 GHz, from our model fit is 3-57%. It is similar to the estimate obtained from the thermal absorption properties (10-40% at 1 GHz). In the case of the 3C391 the conclusions are not so clear. The results from our model fit (thermal emission contribution of 10-25% at 1 GHz) and results obtained from the low frequency absorption (thermal contribution of 0.15-7% at 1 GHz) do not overlap. For the SNR 3C396 we suggest that if previously detected thermal absorption could be intrinsic to the SNR then the thermal emission (<47% at 1 GHz from our model fit) could be significant enough to shape the radio continuum spectrum at high frequencies. Polarization observations for these SNRs can constrain the strength of a thermal component. Reliable observations at low frequencies (<100 MHz) are needed as well as more data at high radio frequencies (>1 GHz)...

Constraints on the Massive Supernova Progenitors

Arbutina, Bojan
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 24/02/2007
Relevância na Pesquisa
16.79%
Generally accepted scheme distinguishes two main classes of supernovae (SNe): Ia resulting from the old stellar population (deflagration of a white dwarf in close binary systems), and SNe of type II and Ib/c whose ancestors are young massive stars (died in a core-collapse explosion). Concerning the latter, there are suggestions that the SNe II are connected to early B stars, and SNe Ib/c to isolated O or Wolf-Rayet (W-R) stars. However, little or no effort was made to further separate SNe Ib from Ic. We have used assumed SN rates for different SN types in spiral galaxies in an attempt to perform this task. If isolated progenitor hypothesis is correct, our analysis indicates that SNe Ib result from stars of main-sequence mass $23 \mathcal{M}_{\odot} \lesssim \mathcal{M} \lesssim 30 \mathcal{M}_{\odot}$, while the progenitors of SNe Ic are more massive stars with $\mathcal{M} \gtrsim 30 \mathcal{M}_{\odot}$. Alternatively, if the majority of SNe Ib/c appear in close binary systems (CBs) then they would result from the same progenitor population as most of the SNe II, i.e. early B stars with initial masses of order $\mathcal{M} \sim 10 \mathcal{M}_{\odot}$. Future observations of SNe at high-redshift ($z$) and their rate will provide us with unique information on SN progenitors and star-formation history of galaxies. At higher-$z$ (deeper in the cosmic past) we expect to see the lack of type Ia events...

The orthogonal fitting procedure for determination of the empirical {\Sigma} - D relations for supernova remnants: application to starburst galaxy M82

Urosevic, D.; Vukotic, B.; Arbutina, B.; Sarevska, M.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
16.79%
The radio surface brightness-to-diameter ({\Sigma} - D) relation for supernova remnants (SNRs) in the starburst galaxy M82 is analyzed in a statistically more robust manner than in the previous studies that mainly discussed sample quality and related selection effects. The statistics of data fits in log {\Sigma} - log D plane are analyzed by using vertical (standard) and orthogonal regressions. As the parameter values of D - {\Sigma} and {\Sigma} - D fits are invariant within the estimated uncertainties for orthogonal regressions, slopes of the empirical {\Sigma} - D relations should be determined by using the orthogonal regression fitting procedure. Thus obtained {\Sigma} - D relations for samples which are not under severe influence of the selection effects could be used for estimating SNR distances. Using the orthogonal regression fitting procedure {\Sigma} - D slope {\beta} \approx 3.9 is obtained for the sample of 31 SNRs in M82. The results of implemented Monte Carlo simulations show that the sensitivity selection effect does not significantly influence the slope of M82 relation. This relation could be used for estimation of distances to SNRs that evolve in denser interstellar environment, with number denisty up to 1000 particles per cm3 .; Comment: 14 pages...