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Percentagem de plaquetas reticuladas : um parâmetro útil no diagnóstico da Púrpura Trombocitopénica Imune Primária

Pinheiro, Ana Cristina da Costa Abrantes
Fonte: Universidade de Coimbra Publicador: Universidade de Coimbra
Tipo: Dissertação de Mestrado
POR
Relevância na Pesquisa
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A Púrpura Trombocitopénica Imune (PTI) é uma doença auto-imune que se caracteriza pela presença de auto-anticorpos contra as glicoproteínas plaquetares, que levam à destruição das plaquetas no sistema reticulo-endotelial. Para o diagnóstico diferencial entre trombocitopenias por hiperdestruição periférica, como a PTI, ou por hipoprodução medular (aplasia ou invasão medular por proliferação celular anormal) é necessário, frequentemente, fazer a observação morfológica da medula óssea. As plaquetas reticuladas (rP – reticulated platelet) são plaquetas recentemente libertadas da medula óssea, têm um maior volume, são mais densas e têm ácido ribonucleico (RNA – ribonucleic acid) residual. A percentagem de rP (%rP) é um novo parâmetro plaquetar do CELL-DYN® Sapphire que utiliza o marcador de fluorescência CD4K-530. Objectivo: O objectivo principal deste trabalho é determinar a fiabilidade da %rP na avaliação da actividade trombopoiética da medula óssea, com o intuito de vir a substituir o medulograma na abordagem diagnóstica da maioria dos casos de PTI primária. Material e métodos: Em 139 amostras de sangue periférico, colhidas em ácido etilenodiaminotetracético tripotássico (EDTA K3 – ethylenediaminetetraacetic acid tripotassic)...

Avaliação dos danos por fluência no superaquecedor da caldeira de CO da REFAP S/A segundo API STD 530

Winck Junior, João Carlos
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Dissertação Formato: application/pdf
POR
Relevância na Pesquisa
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A capacidade de avaliar de forma segura a vida remanescente de componentes que operam na zona de fluência, garantindo a integridade estrutural entre inspeções, tornou-se um fator de extrema importância na operação de caldeiras que já operam há muitos anos, freqüentemente já tendo suplantado a vida de projetos. O superaquecedor da caldeira de CO da REFAP que já opera há 30 anos dentro da zona de fluência, foi avaliado baseado na metodologia proposta no API STD 530 para determinação da sua vida remanescente, com o objetivo de garantir a sua continuidade operacional de forma segura. Foram utilizadas duas abordagens para o tratamento dos dados de temperatura e pressão ao longo dos anos: uma baseada em intervalos de inspeção, e outra, baseada em uma metodologia de árvore de decisões, separando os dados em faixas de temperatura. As duas abordagens foram analisadas e mostraram resultados semelhantes. Com base nos resultados, pode-se afirmar que, respeitadas às condições de projeto, não é esperado que o superaquecedor da caldeira de CO da REFAP venha a falhar por fluência nos próximos anos.; The ability to assess correctly the remaining life of components operating in the creep range, ensuring integrity between inspections intervals...

Vibrational analysis of d-PCL(530)/siloxane based hybrids doped with two lithium salts

Ferreira, C. B.; Fernandes, M.; Rodrigues, L. C.; Silva, Maria Manuela; Smith, Michael John; Bermudez, V. de Zea
Fonte: Springer-Verlag Publicador: Springer-Verlag
Tipo: Artigo de Revista Científica
Publicado em /05/2013 ENG
Relevância na Pesquisa
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Published online: 22 May 2013; The present study has been focused on environmentally friendly sol-gel derived electrolytes based on a di-urethane cross-linked d-PCL(530)/siloxane network (where d represents di, PCL identifies the poly(ε–caprolactone) biopolymer and 530 is the average molecular weight in g.mol-1) doped with a wide range of concentration of lithium perchlorate (LiClO4) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). Fourier Transform Infrared and Raman (FT-IR and FT-Raman, respectively) spectroscopies have been applied to evaluate the extent of ionic association. Characteristic bands of the PCL(530) segments, of the urethane cross-links and of the anions have been examined to gain insight into the cation/biopolymer, cation/anion and cation/cross-link interactions. In both electrolyte systems “free” ions and contact ions have been identified. The addition of salt modifies the hydrogen-bonded array of the host matrix, causing the destruction/formation of the urethane/urethane aggregates.; Fundação para a Ciência e a Tecnologia (FCT)

Structural changes in the 530 loop of Escherichia coli 16S rRNA in mutants with impaired translational fidelity.

Van Ryk, D I; Dahlberg, A E
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 11/09/1995 EN
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The higher order structure of the functionally important 530 loop in Escherichia coli 16S rRNA was studied in mutants with single base changes at position 517, which significantly impair translational fidelity. The 530 loop has been proposed to interact with the EF-Tu-GTP-aatRNA ternary complex during decoding. The reactivity at G530, U531 and A532 to the chemical probes kethoxal, CMCT and DMS respectively was increased in the mutant 16S rRNA compared with the wild-type, suggesting a more open 530 loop structure in the mutant ribosomes. This was supported by oligonucleotide binding experiments in which probes complementary to positions 520-526 and 527-533, but not control probes, showed increased binding to the 517C mutant 70S ribosomes compared with the non-mutant control. Furthermore, enzymatic digestion of 70S ribosomes with RNase T1, specific for single-stranded RNA, substantially cleaved both wild-type and mutant rRNAs between G524 and C525, two of the nucleotides involved in the 530 loop pseudoknot. This site was also cleaved in the 517C mutant, but not wild-type rRNA, by RNase V1. Such a result is still consistent with a more open 530 loop structure in the mutant ribosomes, since RNase V1 can cut at appropriately stacked single-stranded regions of RNA. Together these data indicate that the 517C mutant rRNA has a rather extensively unfolded 530 loop structure. Less extensive structural changes were found in mutants 517A and 517U...

A mutation in the 530 loop of Escherichia coli 16S ribosomal RNA causes resistance to streptomycin.

Melançon, P; Lemieux, C; Brakier-Gingras, L
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 25/10/1988 EN
Relevância na Pesquisa
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Oligonucleotide-directed mutagenesis was used to introduce an A to C transversion at position 523 in the 16S ribosomal RNA gene of Escherichia coli rrnB operon cloned in plasmid pKK3535. E. coli cells transformed with the mutated plasmid were resistant to streptomycin. The mutated ribosomes isolated from these cells were not stimulated by streptomycin to misread the message in a poly(U)-directed assay. They were also restrictive to the stimulation of misreading by other error-promoting related aminoglycoside antibiotics such as neomycin, kanamycin or gentamicin, which do not compete for the streptomycin binding site. The 530 loop where the mutation in the 16S rRNA is located has been mapped at the external surface of the 30S subunit, and is therefore distal from the streptomycin binding site at the subunit interface. Our results support the conclusion that the mutation at position 523 in the 16S rRNA does not interfere with the binding of streptomycin, but prevents the drug from inducing conformational changes in the 530 loop which account for its miscoding effect. Since this effect primarily results from a perturbation of the translational proofreading control, our results also provide evidence that the 530 loop of the 16S rRNA is involved in this accuracy control.

African Swine Fever Virus Multigene Family 360 and 530 Genes Affect Host Interferon Response

Afonso, C. L.; Piccone, M. E.; Zaffuto, K. M.; Neilan, J.; Kutish, G. F.; Lu, Z.; Balinsky, C. A.; Gibb, T. R.; Bean, T. J.; Zsak, L.; Rock, D. L.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /02/2004 EN
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African swine fever virus (ASFV) multigene family 360 and 530 (MGF360/530) genes affect viral growth in macrophage cell cultures and virulence in pigs (L. Zsak, Z. Lu, T. G. Burrage, J. G. Neilan, G. F. Kutish, D. M. Moore, and D. L. Rock, J. Virol. 75:3066-3076, 2001). The mechanism by which these novel genes affect virus-host interactions is unknown. To define MGF360/530 gene function, we compared macrophage transcriptional responses following infection with parental ASFV (Pr4) and an MGF360/530 deletion mutant (Pr4Δ35). A swine cDNA microarray containing 7,712 macrophage cDNA clones was used to compare the transcriptional profiles of swine macrophages infected with Pr4 and Pr4Δ35 at 3 and 6 h postinfection (hpi). While at 3 hpi most (7,564) of the genes had similar expression levels in cells infected with either virus, 38 genes had significantly increased (>2.0-fold, P < 0.05) mRNA levels in Pr4Δ35-infected macrophages. Similar up-regulation of these genes was observed at 6 hpi. Viral infection was required for this induced transcriptional response. Most Pr4Δ35 up-regulated genes were part of a type I interferon (IFN) response or were genes that are normally induced by double-stranded RNA and/or viral infection. These included monocyte chemoattractant protein...

CNTO 530 functions as a potent EPO mimetic via unique sustained effects on bone marrow proerythroblast pools

Sathyanarayana, Pradeep; Houde, Estelle; Marshall, Deborah; Volk, Amy; Makropoulos, Dorie; Emerson, Christine; Pradeep, Anamika; Bugelski, Peter J.; Wojchowski, Don M.
Fonte: American Society of Hematology Publicador: American Society of Hematology
Tipo: Artigo de Revista Científica
Publicado em 14/05/2009 EN
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Anemia as associated with numerous clinical conditions can be debilitating, but frequently can be treated via administration of epoetin-alfa, darbepoietin-alfa, or methoxy-PEG epoetin-beta. Despite the complexity of EPO-EPO receptor interactions, the development of interesting EPO mimetic peptides (EMPs) also has been possible. CNTO 530 is one such novel MIMETIBODY Fc-domain dimeric EMP fusion protein. In a mouse model, single-dose CNTO 530 (unlike epoetin-alfa or darbepoietin-alfa) bolstered red cell production for up to 1 month. In 5-fluorouracil and carboplatin-paclitaxel models, CNTO 530 also protected against anemia with unique efficiency. These actions were not fully accounted for by half-life estimates, and CNTO 530 signaling events therefore were studied. Within primary bone marrow erythroblasts, kinetics of STAT5, ERK, and AKT activation were similar for CNTO 530 and epoetin-alfa. p70S6K activation by CNTO 530, however, was selectively sustained. In vivo, CNTO 530 uniquely stimulated the enhanced formation of PODXLhighCD71high (pro)erythroblasts at frequencies multifold above epoetin-alfa or darbepoietin-alfa. CNTO 530 moreover supported the sustained expansion of a bone marrow–resident KitnegCD71highTer119neg progenitor pool. Based on these distinct erythropoietic and EPOR signaling properties...

CNTO 530 Increases Expression of HbA and HbF in Murine Models of β-Thalassemia and Sickle Cell Anemia

Makropoulos, Dorie A; Achuthanandam, Ram; Avery, Justin; Wilson, Krista; Brosnan, Kerry; Miller, Andrew; Nesspor, Thomas; Chroscinski, Denise; Walker, Mindi; Egenolf, Devon; Huang, ChiChi; Bugelski, Peter J
Fonte: Bentham Science Publishers Publicador: Bentham Science Publishers
Tipo: Artigo de Revista Científica
EN
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CNTO 530 is an erythropoietin receptor agonist MIMETIBODYTM construct. CNTO 530 has been shown to be active in a number of rodent models of acquired anemia (e.g. renal insufficiency and chemotherapy induced anemia). We investigated the efficacy of CNTO 530 in murine models of β-thalassemia and sickle cell anemia (Berkeley mice). β- thalassemic mice are deficient in expression of α-globin chain and heterozygous mice are characterized by a clinical syndrome similar to the human β-thalassemia intermedia. Berkeley mice are knocked out for murine alpha and beta globin and are transgenic for human alpha, beta (sickle) and gamma globin genes. Berkeley mice thus express human sickle hemoglobin A (HbS) and can also express human fetal hemoglobin. These mice express a severe compensated hypochromic microcytic anemia and display the sickle cell phenotype. To test the effectiveness of CNTO 530, mice from both genotypes received a single subcutaneous (s.c.) dose of CNTO 530 or darbepoetin-α (as a comparator) at 10,000 U/kg, a dose shown to cause a similar increase in reticulocytes and hemoglobin in normal mice. Hematologic parameters were evaluated over time. CNTO 530, but not darbepoetin-α, increased reticulocytes, red blood cells and total hemoglobin in β- thalassemic mice. In Berkeley mice CNTO 530 showed an increase in reticulocytes...

Csk-Induced Phosphorylation of Src at Tyrosine 530 is Essential for H2O2-Mediated Suppression of ERK1/2 in Human Umbilical Vein Endothelial Cells

Jeon, Bo Kyung; Kwon, Kihwan; Kang, Jihee Lee; Choi, Youn-Hee
Fonte: Nature Publishing Group Publicador: Nature Publishing Group
Tipo: Artigo de Revista Científica
Publicado em 03/08/2015 EN
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Mitogen-activated protein kinases (MAPKs) are key signal transducers involved in various cellular events such as growth, proliferation, and differentiation. Previous studies have reported that H2O2 leads to phosphorylation of extracellular signal-regulated kinase (ERK), one of the MAPKs in endothelial cells. The current study shows that H2O2 suppressed ERK1/2 activation and phosphorylation at specific concentrations and times in human umbilical vein endothelial cells but not in immortalized mouse aortic endothelial cells or human astrocytoma cell line CRT-MG. Phosphorylation of other MAPK family members (i.e., p38 and JNK) was not suppressed by H2O2. The decrease in ERK1/2 phosphorylation induced by H2O2 was inversely correlated with the level of phosphorylation of Src tyrosine 530. Using siRNA, it was found that H2O2-induced suppression of ERK1/2 was dependent on Csk. Physiological laminar flow abrogated, but oscillatory flow did not affect, the H2O2-induced suppression of ERK1/2 phosphorylation. In conclusion, H2O2-induced Csk translocation to the plasma membrane leads to phosphorylation of Src at the tyrosine 530 residue resulting in a reduction of ERK1/2 phosphorylation. Physiological laminar flow abrogates this effect of H2O2 by inducing phosphorylation of Src tyrosine 419. These findings broaden our understanding of signal transduction mechanisms in the endothelial cells against oxidative stress.

A Ação Direta de Inconstitucionalidade nº 4.530 e a regulamentação dos serviços

Godoy, Arnaldo Sampaio de Moraes
Fonte: Superior Tribunal de Justiça do Brasil Publicador: Superior Tribunal de Justiça do Brasil
Tipo: Artigo de Revista Científica
PT_BR
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Argumenta em favor da lei regulamentadora dos serviços de mototaxi e de motofrete no contexto da ADI nº 4.530.

Milho verde e feijão-caupi cultivados em consórcio sob diferentes lâminas de irrigação e doses de fósforo.

BLANCO, F. F.; CARDOSO, M. J.; FREIRE FILHO, F. R.; VELOSO, M. E. da C.; NOGUEIRA, C. C. P.; DIAS, N. da S.
Fonte: Pesquisa Agropecuária Brasileira, Brasília, v. 46, n. 5, p. 524-530, maio, 2011. Publicador: Pesquisa Agropecuária Brasileira, Brasília, v. 46, n. 5, p. 524-530, maio, 2011.
Tipo: Artigo em periódico indexado (ALICE)
PT_BR
Relevância na Pesquisa
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O objetivo deste trabalho foi avaliar a resposta de milho verde (Zea mays) e de feijão-caupi (Vigna unguiculata), cultivados em consórcio, a lâminas de irrigação e doses de fósforo. Os experimentos foram realizados em 2008 e 2009, em delineamento de blocos ao acaso, com 25 tratamentos e quatro repetições. Os tratamentos consistiram de cinco lâminas de irrigação, a 70, 110, 140, 180 e 220% da evapotranspiração da cultura, e de cinco doses de P2O5 a 0, 50, 100, 150 e 200% da dose de P recomendada. O milho foi semeado no espaçamento 0,80x0,40 m, e o feijão-caupi foi semeado dentro das linhas entre as plantas de milho. Não houve efeito das doses de P2O5; porém, a resposta às lâminas de irrigação foi quadrática em milho e linear em feijão-caupi. As máximas produtividades técnicas de espigas de milho verde com palha (10,76 Mg ha-1) e sem palha (7,62 Mg ha-1) foram obtidas com a lâmina de 530 mm, intermediária às lâminas referentes a 180 e 220% da evapotranspiração da cultura. A maior produtividade de grãos verdes de feijão-caupi (3,40 Mg ha-1) foi obtida com a maior lâmina de água aplicada, de 644 mm.; 2011

Milho verde e feijão-caupi cultivados em consórcio sob diferentes lâminas de irrigação e doses de fósforo.

BLANCO, F.F.; CARDOSO, M.J.; FILHO, F.R.F.; VELOSO, M.E. da C.; NOGUEIRA, C.C.P.; DIAS, N. da S.
Fonte: Pesquisa Agropec. bras., Brasília, v.46, n.5, p.524-530, maio 2011 Publicador: Pesquisa Agropec. bras., Brasília, v.46, n.5, p.524-530, maio 2011
Tipo: Artigo em periódico indexado (ALICE)
PT_BR
Relevância na Pesquisa
26.534775%
O objetivo deste trabalho foi avaliar a resposta de milho verde (Zea mays) e de feijão-caupi (Vigna unguiculata), cultivados em consórcio, a lâminas de irrigação e doses de fósforo. Os experimentos foram realizados em 2008 e 2009, em delineamento de blocos ao acaso, com 25 tratamentos e quatro repetições. Os tratamentos consistiram de cinco lâminas de irrigação, a 70, 110, 140, 180 e 220% da evapotranspiração da cultura, e de cinco doses de P2O5 a 0, 50, 100, 150 e 200% da dose de P recomendada. O milho foi semeado no espaçamento 0,80x0,40 m, e o feijão-caupi foi semeado dentro das linhas entre as plantas de milho. Não houve efeito das doses de P2O5; porém, a resposta às lâminas de irrigação foi quadrática em milho e linear em feijão-caupi. As máximas produtividades técnicas de espigas de milho verde com palha (10,76 Mg ha-1) e sem palha (7,62 Mg ha-1) foram obtidas com a lâmina de 530 mm, intermediária às lâminas referentes a 180 e 220% da evapotranspiração da cultura. A maior produtividade de grãos verdes de feijão-caupi (3,40 Mg ha-1) foi obtida com a maior lâmina de água aplicada, de 644 mm.; 2011

Sonates; Sonatas, organ BWV 525-530; Oeuvres complètes pour orgue At head of title:

Bach, Johann Sebastian (1685 - 1750); Fauré, Gabriel (1845 - 1924); Bonnet, Joseph (1884 - 1944)
Fonte: Durand & Cie. Publicador: Durand & Cie.
Tipo: Musical Score Formato: Number of Pages:iii, 74 p. of music; Dimensions:27 x 35 cm
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Pref. and notes in French and English. --- Sonata I [BWV 525] -- Sonata II [BWV 526] -- Sonata III [BWV 527] -- Sonata IV [BWV 528] -- Sonata V [BWV 529] -- Sonata VI [BWV 530].

Beobachtung von kompakten Objekten mit XMM und RXTE. Der anormale Pulsar 1E 1048.1-5937 und der Polar RX J1940.1-1025; Observation of compact objects with XMM and RXTE. The AXP 1E 1048.1-5937 and the Polar RX J1940.1-1025

Göhler, Eckart
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Dissertação
DE_DE
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1E 1048.1-5937 gehört zur Klasse der anormalen Röntgenpulsare (AXP), die sich durch eine Periode um 8 sec und ein sehr weiches Röntgenspektrum auszeichnen. Im allgemeinen geht man davon aus, dass diese Pulsare rotierende Neutronensterne ohne Begleiter sind, die ihre Abstrahlungsenergie entweder aus einer Akkretion oder dem Abbau sehr starker Magnetfelder beziehen. Im Januar 2001 wurde 1E 1048.1-5937 mit dem Röntgensatelliten XMM-Newton beobachtet, und eine mit früheren Beobachtungen konsistente Periode von 6.45252(4) sec, ein Spektrum, welches aus einem Potenzgesetz und einer Schwarzkörperkomponente mit einem Photonenindex von Gamma = 3.0(5) und einer Schwarzkörpertemperatur von KT = 0.64(5) keV gefunden. Mit verschiedenen Auswerteverfahren wurde die Position auf einen mit einer Chandra-Beobachtung konsistenten Wert von = 10h 50m 7.s14, = 59 530 21.004 (2000) bestimmt (Wang & Chakrabarty, 2002). Für eine Untersuchung der spektrale Variation, die Hinweise auf die Natur des Objekts liefern kann (vgl. Özel et al., 2001), wurden die spektralen Parameter sowie die Flüsse der spektralen Komponenten in vier verschiedenen Phasenbins bestimmt. Die Schwarzkörper und Potenzgesetzkomponente legen eine Korrelation nahe. Es konnte eine nahezu konstante Schwarzkörpertemperatur...

Endoscopic sphincterotomy in choledocholithiasis: analysis of an experience of 530 interventions.; Esfincterotomia endoscópica na coledocolitíase: análise de uma experiência de 530 intervenções.

Ginestal-Cruz, A; Serviço de Medicina 2, Hospital de Santa Maria/Faculdade de Medicina de Lisboa.; Grima, N; Correia, A P; Duarte, V; Correia, J P
Fonte: Ordem dos Médicos Publicador: Ordem dos Médicos
Tipo: info:eu-repo/semantics/article; article; article; info:eu-repo/semantics/publishedVersion Formato: application/pdf
Publicado em 30/06/1990 POR
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We report the experience of 530 consecutive cases of choledocolithiasis treated through Endoscopic Sphincterotomy (ES) between January 1980 and January 1988 (74% of total patients submitted to ES in the same period). 73% had more than 60 years and 47% more than 70 years. A slight majority (52%) had previous cholecystectomy (1/3 still with T-tube drainage) and the remaining had gallbladders insitu (lithiasic in 82%). Therapeutic goals (achieved drainage and complete stone removal) have been achieved in 95% of patients with a low immediate morbidity (9%) and mortality (1%). Delayed mortality, until 30th day (3%) includes 6 cases of obstructive cholangitis with sepsis, unaltered by emergent ES. Follow-up showed a 3% incidence of reintervention from restenosed ES. Patients with lithiasic gallbladder had a 33% cholecistectomy rate, mostly elective during first month post-ES. Our experience confirms ES as an efficient and safe routine treatment for choledocolithiasis. It should be the first choice in patients with previous cholecystectomy or alithiasic gallbladder and a largely applicable tool in those with associated gallbladder stones. Decision about post-ES cholecystectomy in these patients must be weighed on clinical grounds and according to surgical risk groups.; We report the experience of 530 consecutive cases of choledocolithiasis treated through Endoscopic Sphincterotomy (ES) between January 1980 and January 1988 (74% of total patients submitted to ES in the same period). 73% had more than 60 years and 47% more than 70 years. A slight majority (52%) had previous cholecystectomy (1/3 still with T-tube drainage) and the remaining had gallbladders insitu (lithiasic in 82%). Therapeutic goals (achieved drainage and complete stone removal) have been achieved in 95% of patients with a low immediate morbidity (9%) and mortality (1%). Delayed mortality...

Centro de investigaciones agronómicas, Maracay. Sección de zootecnia. Novillo Aureola. Nº 530

Hruskovec, Martín
Fonte: Maracay; Venezuela; Aragua Publicador: Maracay; Venezuela; Aragua
ES
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Centro de Investigaciones Agronómicas. Novillo Aureola. Nº 530

Periodic Radio Variability in NRAO 530: Phase Dispersion Minimization Analysis

Lu, Jun-Chao; Wang, Jun-Yi; An, Tao; Lin, Ji-Ming; Qiu, Hong-Bing
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 17/02/2012
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In this paper, a periodicity analysis of the radio light curves of the blazar NRAO 530 at 14.5, 8.0, and 4.8 GHz is presented employing an improved Phase Dispersion Minimization (PDM) technique. The result, which shows two persistent periodic components of $ \sim 6$ and $ \sim 10$ years at all three frequencies, is consistent with the results obtained with the Lomb-Scargle periodogram and weighted wavelet Z-transform algorithms. The reliability of the derived periodicities is confirmed by the Monte Carlo numerical simulations which show a high statistical confidence. (Quasi-)Periodic fluctuations of the radio luminosity of NRAO 530 might be associated with the oscillations of the accretion disk triggered by hydrodynamic instabilities of the accreted flow. \keywords{methods: statistical -- galaxies: active -- galaxies: quasar: individual: NRAO 530}; Comment: 8 pages, 5 figures, accepted by RAA

High-frequency very long baseline interferometry studies of NRAO 530

Lu, R. -S.; Krichbaum, T. P.; Zensus, J. A.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
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NRAO 530 is an optically violent variable source and has been studied with multi-epoch multi-frequency high-resolution VLBI observations. NRAO 530 was monitored with the VLBA at three frequencies (22, 43 and 86 GHz) on 10 consecutive days in 2007 May during observations of the Galactic Center (Sgr A*). Furthermore, analysis of archival data of NRAO 530 at 15 GHz over the last ten years allows us to study its detailed jet kinematics. We identified the compact component located at the southern-end of the jet as the VLBI core, consistent with previous studies. The 10-d monitoring data at the 3 high frequencies were shown to produce high quality and self-consistent measurements of the component positions, from which we detected for the first time a two-dimensional frequency-dependent position shift. In addition, the repeated measurements also permit us to investigate the interday flux density and structure variability of NRAO 530. We find that it is more variable for the inner jet components than those further out. We obtained apparent velocities for eight jet components with $\beta_{\rm app} ranging from 2 to 26 c. Accordingly, we estimated physical jet parameters with the minimum Lorentz factor of 14 and Doppler factors in the range of 14--28 (component f). The changes in the morphology of NRAO 530 were related to the motion of separate jet components with the most pronounced changes occurring in the regions close to the core. For NRAO 530...

Time delay and lens redshift for the doubly imaged BAL quasar SBS1520+530

Burud, I.; Hjorth, J.; Courbin, F.; Cohen, J. G.; Magain, P.; Jaunsen, A. O.; Kaas, A. A.; Faure, C.; Letawe, G.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 05/06/2002
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We present optical R-band light curves of the gravitationally lensed quasar SBS1520+530 derived from data obtained at the Nordic Optical Telescope. A time delay of 130+/-3 days (1 sigma) is determined from the light curves. In addition, spectra of SBS1520+530 obtained at the Keck Observatory are spatially deconvolved in order to extract the spectrum of the faint lensing galaxy, free of any contamination by the light from the bright quasar images. This spectrum indicates a lens redshift z=0.717, in agreement with one of the absorption systems found in the quasar spectra. The best mass model of the system includes a second nearby galaxy and a cluster of galaxies in addition to the main lensing galaxy. Adopting this model and an Omega=0.3, Lambda=0.7 cosmology, our time-delay measurement yields a Hubble constant of H_0=51+/- 9, km/s/Mpc (1 sigma error).; Comment: 7 pages, accepted for publication in A&A

Multiple periodic oscillations in the radio light curves of NRAO 530

Xie, Mingjie; Wang, Junyi; An, Tao; Zheng, Lin; Han, Xu
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 13/09/2012
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In this paper, the time series analysis method CLEANest is employed to search for characteristic periodicities in the radio light curves of the blazar NRAO 530 at 4.8, 8.0 and 14.5 GHz over a time baseline of three decades. Two prominent periodicities on time scales of about 6.3 and 9.5 yr are identified at all three frequencies, in agreement with previous results derived from different numerical techniques, confirming the multiplicity of the periodicities in NRAO 530. In addition to these two significant periods, there is also evidence of shorter-timescale periodicities of about 5.0 yr, 4.2 yr, 3.4 yr and 2.8 yr showing lower amplitude in the periodograms. The physical mechanisms responsible for the radio quasi-periodic oscillations and the multiplicity of the periods are discussed.; Comment: accepted for publication in SCIENCE CHINA (Physics, Mechanics & Astronomy), 8 pages, 7 figures