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Estudo sobre a sensibilidade dos parâmetros do método SCS na determinação de hidrogramas de cheia em bacias urbanas; Study on the SCS method parameter sensitivity in determination of flood hydrographs in urban basin

Paulino, Paloma Fernandes
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 30/09/2014 PT
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Para simular o comportamento da bacia hidrográfica diante de eventos chuvosos e, a partir da quantificação das vazões de cheias, encontrar soluções para os problemas causados pelas enchentes, é essencial a utilização de modelos de transformação chuva-vazão. Há diferentes métodos para o cálculo do deflúvio superficial ou precipitação excedente para uma dada bacia hidrográfica. Entre estes, um dos mais utilizados pela comunidade técnica é o método desenvolvido pelo Departamento de Conservação do Solo norte-americano: SCS (Soil Conservation Service, atual National Resources Conservation Service), aplicável principalmente quando não se dispõe de séries históricas de dados hidrológicos. A utilização deste método depende da seleção do parâmetro CN (Curve Number), que por sua vez requer o conhecimento das características da bacia hidrográfica em estudo, como: tipos de solo, cobertura vegetal, uso da terra, teor de umidade do solo anterior à chuva. A partir da precipitação excedente total do evento chuvoso, para se construir um hidrograma de cheia, é necessário distribuir a chuva ao longo do tempo, ou seja, construir o hietograma da precipitação excedente. O SCS também propõe um método baseado no hidrograma unitário triangular sintético para gerar o hidrograma de cheia a partir de um certo hietograma. O parâmetro básico para se obter esse hidrograma sintético é o tempo de concentração da bacia hidrográfica (tc). Para a determinação deste parâmetro existem diversas fórmulas empíricas baseadas nas características físicas da bacia hidrográfica...

Síntese de manganita dopada com estrôncio e cobaltita dopada com antimônio e caracterização microestrutural

Tarragó, Diego Pereira
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Dissertação Formato: application/pdf
POR
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A grande variedade de propriedades dos óxidos com estrutura perovskita permite sua aplicação em diversas áreas da tecnologia. Em especial, as propriedades eletroquímicas e a estabilidade térmica de alguns destes compostos faz destes materiais os mais usados em cátodos de dispositivos para geração de energia como as células a combustível de óxido sólido (SOFC). As SOFC são dispositivos que podem atingir altas eficiências na conversão de energia elétrica e são passíveis de utilização na geração de energia sustentável e distribuída. Para estas células, as perovskitas compostas de manganita de lantânio dopada com estrôncio (LSM) preenche a maioria dos requisitos para aplicação como cátodos da SOFC. Nas células a combustível de óxido sólido de temperatura intermediária (IT-SOFC) há a possibilidade de construir a célula com filmes finos dos materiais cerâmicos suportados em um interconector metálico. No entanto, para os cátodos das IT-SOFC as manganitas não possuem bom desempenho eletroquímico devido à menor temperatura de operação do dispositivo, sendo necessário o desenvolvimento de condutores mistos para aumentar os sítios reativos para reação de redução do O2. Assim, o desenvolvimento de cátodos utilizando a perovskita cobaltita de estrôncio dopada com antimônio (SCS) tem sido proposto para esta aplicação. Portanto...

Design e caracterização de junções ScS em nióbio; Design and characterization of ScS junctions in niobium

Felipe Gustavo da Silva Santos
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 10/05/2013 PT
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Dispositivos baseados em junções Josephson tem desempenhado um papel importante tanto em ciências básicas quanto aplicadas. Neste trabalho, descrevemos a fabricação e caracterização DC de junções Josephson do tipo ScS (superconductor-constrição-supercondutor). Os dispositivos exibem uma característica VI que concorda com o bem conhecido modelo RSJ (resistência nula abaixo de uma corrente crítica mas constante e não nula acima dessa corrente) para temperaturas ~ 2 K. Para temperaturas um pouco maiores, observamos vários estados resistivos na curva VI, os quais são tipicamente atribuídos ao fluxo de vórtices de Abrikosov no interior da constrição. As medidas, porém, também sugerem que este pode não ser o caso nesses dispositivos devido à pequena magnitude do campo magnético autoinduzido na constrição, se comparado aos campos típicos que a levariam ao estado misto; Josephson junction devices have played a role in fundamental and applied sciences. In this work, we report the fabrication and DC characterization of niobium Josephson junctions of the ScS (superconductor-constriction-superconductor) type. The devices exhibit a VI characteristic in accordance with the well known RSJ model (vanishing resistance below a critical current and constant nonzero resistance above it) for temperatures ~ 2 K. For slightly higher temperatures...

Síntese e caracterização de nano emissores de YAG : Dy para LEDs

Forte, Paulo Manuel Figueiras
Fonte: Universidade de Aveiro Publicador: Universidade de Aveiro
Tipo: Dissertação de Mestrado
POR
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Este trabalho teve como objetivo principal a utilização de uma técnica de síntese eficiente e de baixo custo para a produção de nano emissores de granada de ítrio e alumínio (YAG) dopado com iões trivalentes de disprósio (YAG:Dy). A técnica adotada foi a síntese por auto combustão em solução (SCS) com combinação de combustíveis. Numa primeira fase estudou-se a influência dos combustíveis (ureia, glicina e a combinação dos dois) na qualidade estrutural e ótica do material produzido, neste caso YAG dopado com térbio, com vista a identificar o método de produção mais eficaz. Estudou-se de seguida a influência da percentagem da dopagem de disprósio na qualidade dos materiais produzidos usando uma combinação de ureia e glicina em quantidades estequiométricas. Durante a síntese identificou-se que o processo dava origem a materiais com diferentes propriedades em função da sua localização no reator, pelo que foi igualmente realizado um estudo comparativo destes dois materiais e como as suas propriedades eram influenciadas por tratamentos térmicos pós-síntese. Também a influência do tipo de reator, forno ou placa de aquecimento, nas referidas propriedades foi estudada para os materiais produzidos. Foram utilizadas técnicas de difração de raios-X...

The Zw5 protein, a component of the scs chromatin domain boundary, is able to block enhancer–promoter interaction

Gaszner, Miklos; Vazquez, Julio; Schedl, Paul
Fonte: Cold Spring Harbor Laboratory Press Publicador: Cold Spring Harbor Laboratory Press
Tipo: Artigo de Revista Científica
Publicado em 15/08/1999 EN
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The scs and scs′ elements were proposed to function as chromatin domain boundaries for the 87A7 heat shock locus in Drosophila melanogaster. Here we report the identification and characterization of SBP (scs binding protein), a component of the scs nucleoprotein complex. SBP binds specifically to a 24-bp region of scs in vitro and is associated with scs in vivo. Multiple copies of an oligonucleotide containing the SBP recognition sequence are capable of blocking enhancer–promoter interactions in transgene assays. Mutations in the oligonucleotide that disrupt SBP binding in vitro also eliminate enhancer-blocking activity in vivo. We show that SBP is encoded by the zeste-white 5 gene and that mutations in zeste-white 5 reduce the enhancer-blocking activity of the multimerized oligonucleotides.

Studies of the Role of the Drosophila scs and scs′ Insulators in Defining Boundaries of a Chromosome Puff

Kuhn, Emily J.; Hart, Craig M.; Geyer, Pamela K.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /02/2004 EN
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Insulators are DNA elements that establish independent transcriptional domains within eukaryotic genomes. The Drosophila scs and scs′ insulators localize near the borders of a structural domain in the polytene chromosomes, known as a puff, produced by transcription of the 87A heat shock protein (hsp) genes. It has been suggested that scs and scs′ are boundary elements that delimit this decondensed chromatin domain, reflecting the mechanism by which these sequences act to constrain regulatory interactions. This model was tested using transposons that carried a yellow gene to assess enhancer blocking and an hsp70-lacZ gene to examine the structure of a heat shock puff in the presence and absence of insulators. We found that although scs and scs′ blocked enhancer function, these sequences did not prevent the spread of decondensation resulting from hsp70-lacZ transcription. Further analysis of the endogenous 87A locus demonstrated that scs and scs′ reside within, not at, the borders of the puff. Taken together, our studies suggest that scs and scs′ are not boundary elements that block the propagation of an altered chromatin state associated with puff formation. We propose that these insulators may have a direct role in limiting regulatory interactions in the gene-dense 87A region.

Detailed mapping of the species cytoplasm-specific (scs) gene in durum wheat.

Simons, Kristin J; Gehlhar, Sarah B; Maan, Shivcharan S; Kianian, Shahryar F
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /12/2003 EN
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The compatibility-inducing action of the scs(ti) (species cytoplasm-specific gene derived from Triticum timopheevii) and Vi (vitality) genes can be observed when a durum (T. turgidum) nucleus is placed in T. longissimum cytoplasm. These two genes restore compatibility between an otherwise incompatible nucleus and cytoplasm. The objective of this study was to localize the scs(ti) gene on a linkage map of chromosome 1A, which could eventually be used to clone the gene. The mapping population consisted of 110 F2 individuals derived from crossing a Langdon-T. dicoccoides chromosome 1A substitution line with a euplasmic (normal cytoplasm) line homozygous for the scs(ti) gene. Through a series of testcrosses the genotypes of the 110 individuals were determined: 22 had two copies, 59 had one copy, and 29 had no copy of the scs(ti) gene. Data from RFLP, AFLP, and microsatellite analysis were used to create a linkage map. The flanking marker loci found for the scs(ti) gene were Xbcd12 and Xbcd1449-1A.2 with distances of 2.3 and 0.6 cM, respectively. Nearly 10% of individuals in this population were double recombinant for a genetic interval of <3 cM. A blistering phenotype reminiscent of the phenotype observed in maize brittle-1 mutable was also evident in these individuals. The higher frequency of double recombination within this region and seed-blistering phenotype could be an indication of a transposable element(s) in this locus.

Transplantation of expanded bone marrow-derived very small embryonic-like stem cells (VSEL-SCs) improves left ventricular function and remodelling after myocardial infarction

Zuba-Surma, Ewa K; Guo, Yiru; Taher, Hisham; Sanganalmath, Santosh K; Hunt, Greg; Vincent, Robert J; Kucia, Magda; Abdel-Latif, Ahmed; Tang, Xian-Liang; Ratajczak, Mariusz Z; Dawn, Buddhadeb; Bolli, Roberto
Fonte: Blackwell Publishing Ltd Publicador: Blackwell Publishing Ltd
Tipo: Artigo de Revista Científica
EN
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Adult bone marrow-derived very small embryonic-like stem cells (VSEL-SCs) exhibit a Sca-1+/Lin–/CD45– phenotype and can differentiate into various cell types, including cardiomyocytes and endothelial cells. We have previously reported that transplantation of a small number (1 × 106) of freshly isolated, non-expanded VSEL-SCs into infarcted mouse hearts resulted in improved left ventricular (LV) function and anatomy. Clinical translation, however, will require large numbers of cells. Because the frequency of VSEL-SCs in the marrow is very low, we examined whether VSEL-SCs can be expanded in culture without loss of therapeutic efficacy. Mice underwent a 30 min. coronary occlusion followed by reperfusion and, 48 hrs later, received an intramyocardial injection of vehicle (group I, n= 11), 1 × 105 enhanced green fluorescent protein (EGFP)-labelled expanded untreated VSEL-SCs (group II, n= 7), or 1 × 105 EGFP-labelled expanded VSEL-SCs pre-incubated in a cardiogenic medium (group III, n= 8). At 35 days after myocardial infarction (MI), mice treated with pre-incubated VSEL-SCs exhibited better global and regional LV systolic function and less LV hypertrophy compared with vehicle-treated controls. In contrast, transplantation of expanded but untreated VSEL-SCs did not produce appreciable reparative benefits. Scattered EGFP+ cells expressing α-sarcomeric actin...

A frequency-based linguistic approach to protein decoding and design: Simple concepts, diverse applications, and the SCS Package

Motomura, Kenta; Nakamura, Morikazu; Otaki, Joji M.
Fonte: Research Network of Computational and Structural Biotechnology (RNCSB) Organization Publicador: Research Network of Computational and Structural Biotechnology (RNCSB) Organization
Tipo: Artigo de Revista Científica
Publicado em 29/03/2013 EN
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Protein structure and function information is coded in amino acid sequences. However, the relationship between primary sequences and three-dimensional structures and functions remains enigmatic. Our approach to this fundamental biochemistry problem is based on the frequencies of short constituent sequences (SCSs) or words. A protein amino acid sequence is considered analogous to an English sentence, where SCSs are equivalent to words. Availability scores, which are defined as real SCS frequencies in the non-redundant amino acid database relative to their probabilistically expected frequencies, demonstrate the biological usage bias of SCSs. As a result, this frequency-based linguistic approach is expected to have diverse applications, such as secondary structure specifications by structure-specific SCSs and immunological adjuvants with rare or non-existent SCSs. Linguistic similarities (e.g., wide ranges of scale-free distributions) and dissimilarities (e.g., behaviors of low-rank samples) between proteins and the natural English language have been revealed in the rank-frequency relationships of SCSs or words. We have developed a web server, the SCS Package, which contains five applications for analyzing protein sequences based on the linguistic concept. These tools have the potential to assist researchers in deciphering structurally and functionally important protein sites...

A physiologically motivated sparse, compact, and smooth (SCS) approach to EEG source localization

Cao, Cheng; Akalin Aca, Zeynep; Kreutz-Delgado, Kenneth; Makeig, Scott
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em //2012 EN
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Here, we introduce a novel approach to the EEG inverse problem based on the assumption that principal cortical sources of multi-channel EEG recordings may be assumed to be spatially sparse, compact, and smooth (SCS). To enforce these characteristics of solutions to the EEG inverse problem, we propose a correlation-variance model which factors a cortical source space covariance matrix into the multiplication of a pre-given correlation coefficient matrix and the square root of the diagonal variance matrix learned from the data under a Bayesian learning framework. We tested the SCS method using simulated EEG data with various SNR and applied it to a real ECOG data set. We compare the results of SCS to those of an established SBL algorithm.

Aspectos metodol??gicos sobre o emprego do m??todo do SCS com aux??lio de ferramentas de geoprocessamento no projeto de estruturas de drenagem de uma rodovia

Tassi, Rutin??ia; Bastos, Cezar Augusto Burkert; Miranda, Talita Caroline
Fonte: Universidade Federal do Rio Grande Publicador: Universidade Federal do Rio Grande
Tipo: Artigo de Revista Científica
POR
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Como nem sempre encontramos dados observados que permitam a obten????o da vaz??o m??xima para o dimensionamento de obras hidr??ulicas de drenagem, ?? necess??rio utilizar m??todos hidrol??gicos que representem os principais processos da transforma????o da precipita????o em vaz??o. O presente artigo apresenta a compara????o entre o dimensionamento hidr??ulico de estruturas de drenagem de um trecho de rodovia, utilizando para obten????o das vaz??es de projeto o M??todo Racional e o Hidrograma Unit??rio Sint??tico (HUS) combinado com o m??todo do Curve Number (CN), estabelecido pelo Soil Conservation Service (SCS). Verificou-se que a economia obtida com o dimensionamento das estruturas segundo os m??todos do SCS seria, em m??dia, superior a 60% em rela????o ao uso do M??todo Racional. Tamb??m discute-se como podem ser utilizadas ferramentas de geoprocessamento na aplica????o das metodologias citadas, destacando as vantagens encontradas nesse processo.; The engineer frequently has not observed flow data, allowing the correct design of hydraulics drainage system, so it is necessary to use hydrologic methods to reproduce the transformation process precipitation in flow (runoff). Due your simplicity, the Rational Method still is used in these cases...

Uma Contribuição Metodológica, através da FTA para a Melhoria do Desempenho do SCS da CHESF

do Socorro Cavalcanti de Melo, Maria; Mariano Pires dos Santos, Cícero (Orientador)
Fonte: Universidade Federal de Pernambuco Publicador: Universidade Federal de Pernambuco
Tipo: Outros
PT_BR
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O presente trabalho tem como objetivo estabelecer diretrizes que possibilitem obter uma melhor disponibilidade do Sistema de Controle e Supervisão - SCS da Companhia Hidro Elétrica do São Francisco - CHESF. Para tanto, utilizou insumos provenientes de dados históricos do SCS, armazenados em Sistemas de Informação da CHESF, e insumos provenientes de relatórios técnicos gerados por dois grupos de trabalho, um criado internamente à CHESF e outro composto por representantes das empresas do grupo ELETROBRÁS. Esses grupos foram formados visando o levantamento de problemas que afetam os Sistemas de Controle e Supervisão das empresas do setor elétrico, o estabelecimento de critérios de manutenção e a definição de indicadores referenciais de disponibilidade desses sistemas. Com base nos insumos colhidos foi utilizado o método Análise da Árvore de Falhas - FTA para determinar as causas de indisponibilidades no SCS. Os resultados dessa análise além de permitir identificar as principais causas de indisponibilidade do SCS, conduziram à elaboração de diretrizes com vistas à priorização das ações gerenciais a serem adotadas na solução dos problemas levantados. Considerando a importância, cada vez maior, dos Sistemas de Controle e Supervisão...

SUBSTITUIÇÃO DA SILAGEM DE CANA-DE-AÇÚCAR PELA SILAGEM DOS RESTOS CULTURAIS DO ABACAXIZEIRO NA ALIMENTAÇÃO DE RUMINANTES; Substitute of sugar cane silage + 0,5 urea (SCS) by pineapple stalk silage (PSS) on the feed ruminants

SANTOS, Sandro de Castro
Fonte: Universidade Federal de Goiás; BR; UFG; Mestrado em Ciência Animal; Ciências Agrárias - Veterinaria Publicador: Universidade Federal de Goiás; BR; UFG; Mestrado em Ciência Animal; Ciências Agrárias - Veterinaria
Tipo: Dissertação Formato: application/pdf
POR
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The objective of this trial was to study the substitution of sugar cane silage + 0,5% urea (SCS) by the pineapple stalk silage (PSS) on the feed ruminants. The trial was done in Goiânia-GO and lasted 95 days. Five non castrated male lambs from Santa Inês breed were utilized, with an average age of eight months and live weight of 30,2kg ± 4,8kg. The experimental design was a 5x5 Latin Square, the diets were isoproteic (13,5% CP) and isoenergetic (63% TDN) and the forage:concentrate ratio was 60:40. The parameters evaluated were the dry matter intake (DMI) and relative voluntary intake (RVI), apparent digestibility of nutrients, nutritive value index, physically effective fiber, rumen pH and rumen kinetics. The treatments were the following: 100% PSS:0% SCS (100P); 75% PSS:25% SCS (75P); 50% PSS:50% SCS (50P); 25% PSS:75% SCS (25P) and 0% PSS:100% SCS (0P). There were no differences (P>0,05) among treatments for the DMI (597,27 g/day) and RVI (58,41 g of MSU/day). The dry matter digestibility (DMD) and neutral detergent fiber digestibility (NDFD) did not differ (P>0,05) among diets. The crude protein digestibility (CPD) increased when SCS was linearly added, whose values were 68,09%; ,57%; 70,68%; 73,06% and 78,05%, respectively for the treatments 100P...

Elektroanalytische Untersuchung von Pd-S-Pincer-Komplexen; Electroanalytical Investigation of Pd-SCS-pincer complexes

Eil, Sebastian
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Masterarbeit
DE_DE
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In dieser Arbeit wurden drei ausgesuchte Pd-S-Pincer-Komplexe elektroanalytisch untersucht. Um die elektrochemischen Eigenschaften dieser Komplexe zu bestimmen wurden zwei elektroanalytische Methoden eingesetzt, die cyclische Voltammetrie und die Elektrolyse. Die mit Hilfe der Cyclovoltammetrie bestimmten Redoxeigenschaften der Pd-S-Pincer-Komplexe 1, 2 und 3 waren sehr ähnlich. Bei allen drei Komplexen wurden Oxidationspeaks beobachtet, wobei kein entsprechender Rückpeak zu sehen war. Im negativen Potentalbereich konnten keine Reduktionssignale festgestellt werden. In Abhängigkeit von der Konzentration und der Spannungsvorschubgeschwindigkeit wurde ein etwas abweichendes Aussehen der Cyclovoltammogramme, aber dennoch übereinstimmende Ergebnisse erhalten. Die Auswertung der erhaltenen Ergebnisse erwiesen sich als schwierig und für den Reaktionsmechanismus konnte nur eine Hypothese aufgestellt werden (ECE-Mechanismus). Folgereaktionen zu elektrochemisch aktiven oder inaktiven Produkten sind genauso möglich wie die Abspaltung des Metalls und die damit verbundene Entstehung der Liganden. Eine Dissoziation des Chlorids in den Komplexen findet nicht statt. Die aus der Elektrolyse der drei Komplexe erhaltenen Ergebnisse waren ebenfalls nicht eindeutig zu interpretieren. Im Vergleich zu anderen untersuchten Systemen wie zum Beispiel Ferrocen/Ferroceniumion wurden keine typischen steady-state-Voltammogramme erhalten. Die mit der Elektrolyse bestimmte Zahl der übertragenen Elektronen war für jeden der Komplexe 1 - 3 anders und konnte nur für eine Vermutung der tatsächlich beteiligten Elektronen dienen. Insgesamt waren die Ergebnisse der elektrochemischen Charakterisierung eher ungewöhnlich und schwer auszuwerten...

A Study to Determine Impacts on Cost and Readiness Of Variations in the Development and Release Cycle of the F/A-18 EF and EA-18G Software Configuration Set (SCS)

Carr, Timothy; Chebi, Carl; Cook, Gerald; Coons, Russell; Prevost, Mike
Fonte: Monterey, California. Naval Postgraduate School. Publicador: Monterey, California. Naval Postgraduate School.
Tipo: Tese de Doutorado
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EMBA Project Report; EXECUTIVE SUMMARY: This project was completed by Patuxent River EMBA Cohort Consulting Team, on behalf of PMA-265, and facilitated through the Naval Postgraduate School Executive MBA program. The three main objectives of the project were: (1) Determine impacts on cost and readiness of variations in the development and release cycle of the F/A-18 E/F and EA-18G System Configuration Set (SCS); (2) Provide the F/A-18 Program Office with a clearer picture of the current trends associated with varying the SCS release cycle; (3) Provide the program office with a means to evaluate cost and readiness impacts of the SCS release cycle. This project focused on four main areas of interest: (1) Identification of fixed and variable costs incurred in the development and fielding of the F/A-18 SCS for use in the identification of cost impacts due to variation in SCS release interval; (2) Programmatic and schedule impacts on external stakeholders due to variations in SCS release interval (3) F/A-18 Fleet training and readiness impacts due to variation in SCS release interval; (4) Determining SCS release plan that balances capability, schedule, costs and impacts to the war fighter to ensure delivery of the right readiness, at the right time...

The activity of the scs and scs' insulator elements is not dependent on chromosomal context.

Dunaway, M; Hwang, J Y; Xiong, M; Yuen, H L
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /01/1997 EN
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Sequence elements that protect a reporter gene from chromosomal position effects or that block enhancer-activated transcription are called insulators. Using a plasmid-based microinjection assay with Xenopus laevis oocytes, we show that the heterologous Drosophila melanogaster scs and scs' insulator elements do not require chromosomal context to block enhancer-activated transcription. A single insulator element partially blocks enhancer-activated transcription, indicating that each element operates independently rather than as part of a pair. Deletion analysis of the 1.8-kb scs element identified a 220-bp fragment from one of the DNase I-hypersensitive regions that has full blocking activity in the oocyte assay. This fragment corresponds to the critical region of the scs mapped in previous studies with Drosophila. A time course of transcription shows that the scs blocks enhancer-activated transcription as early as transcription can be detected, about 30 min after injection. Complete assembly of the DNA template into nucleosomes requires 4 h. The scs and scs' sequences do not block site-specific recombination by FLP recombinase, implying that insulators do not operate by a general mechanism that physically sequesters the DNA. These data are most consistent with a model for insulator action in which direct interaction between the insulator and either the enhancer or promoter confers directionality to enhancer-activated transcription.

Sequences required for enhancer blocking activity of scs are located within two nuclease-hypersensitive regions.

Vazquez, J; Schedl, P
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 15/12/1994 EN
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The Drosophila 87A7 heat shock locus is bordered, on the proximal and distal sides, by two special chromatin structures, scs and scs'. Each structure is characterized by two sets of nuclease-hypersensitive sites, located within moderately G/C-rich DNA, flanking an A/T-rich nuclease-resistant region. scs and scs' have been shown to insulate a white reporter gene from position effects and to prevent enhancer-promoter interactions. These and other properties suggest scs and scs' might function as chromatin domain boundaries. To identify the DNA sequences which are essential for the insulating activity of scs we used an enhancer blocking assay based on the white gene. Sequences capable of suppressing activation of white by its upstream enhancer elements reside within a 900 bp DNA fragment corresponding to the scs chromatin structure. Within this region, DNA fragments associated with the two nuclease-hypersensitive regions are essential for full enhancer blocking activity, while the central A/T-rich region is dispensable. Deletions which remove part of the hypersensitive regions result in intermediate levels of white activity. Insulating activity can, however, be reconstituted by multimerizing DNA fragments from either hypersensitive region. Our results suggest that the scs boundary is assembled from a discrete number of functionally redundant DNA sequences located within both hypersensitive regions and that boundaries act by decreasing the frequency of enhancer-promoter interactions. We also show that certain types of position effects...

Stochastic resonance in an RF SQUID with shunted ScS junction

Turutanov, O. G.; Golovanevskiy, V. A.; Lyakhno, V. Yu.; Shnyrkov, V. I.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
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Using a point (superconductor-constriction-superconductor, ScS) contact in a single-Josephson-junction superconducting quantum interference device (RF SQUID) provides stochastic resonance conditions at any arbitrary small value of loop inductance and contact critical current, unlike SQUIDs with more traditional tunnel (superconductor-insulator-superconductor, SIS) junctions. This is due to the unusual potential energy of the ScS RF SQUID which always has a barrier between two wells thus making the device bistable. This paper presents the results of a numerical simulation of the stochastic dynamics of the magnetic flux in an ScS RF SQUID loop affected by band-limited white Gaussian noise and low-frequency sine signals of small and moderate amplitudes. The difference in stochastic amplification of RF SQUID loops incorporating ScS and SIS junctions is discussed.; Comment: 9 pages, 6 figures, published in Physica A. Some changes and additions are made to the text, Fig.3 is changed, mistypings are excluded in version 2

Clinical and cost-effectiveness analysis of an open label, single-centre, randomised trial of Spinal Cord Stimulation (SCS) versus Percutaneous Myocardial Laser Revascularisation (PMR) in patients with Refractory Angina Pectoris: the SPiRiT trial

Dyer, Matthew T.; Goldsmith, Kimberley A.; Khan, Sadia N.; Sharples, Linda D.; Freeman, C.; Hardy, I.; Buxton, Martin J.; Schofield, Peter M.
Fonte: Universidade de Cambridge Publicador: Universidade de Cambridge
Tipo: Artigo de Revista Científica
EN
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RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are.; Abstract Background Patients with refractory angina have significant morbidity. This study aimed to compare two of the treatment options, Spinal Cord Stimulation (SCS) and Percutaneous Myocardial Laser Revascularisation (PMR) in terms of clinical outcomes and cost-effectiveness. Methods Eligible patients were randomised to PMR or SCS and followed up for exercise tolerance time (ETT), Canadian Cardiovascular Society (CCS) classification and the quality of life measures SF-36, Seattle Angina Questionnaire and the EuroQoL at 3, 12 and 24 months. Utilities were calculated using the EQ-5D and these and costs were compared between groups. The incremental cost-effectiveness ratio (ICER) per QALY for SCS compared to PMR was also calculated. Results At 24 months post-randomisation...

An iterative algorithm for separation of S and ScS waves of great earthquakes

Yu, Zhulin; Ni, Sidao; Wei, Shengji; Zeng, Xiangfang; Wu, Wenbo; Li, Zhiwei
Fonte: Royal Astronomical Society Publicador: Royal Astronomical Society
Tipo: Article; PeerReviewed Formato: application/pdf; application/zip
Publicado em /11/2012
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Teleseismic SH waves are essential for imaging the rupture processes of large earthquakes. However, for great earthquakes (M8+) such as the 2004 Sumatra earthquake, the 2008 Wenchuan earthquake and the recent Tohoku-Oki earthquake, the source duration is very long (>100 s). Thus the direct SH waves are overlapped with ScS waves for epicentral distances larger than 60°, leaving contaminated S waves for source processes modelling. Therefore artefacts in finite fault models of large earthquake could be produced with such contaminated body waves. We propose an iterative algorithm based on the slowness information of S and ScS waves and stacking technique, to separate S and ScS waves with records from a regional seismic network. Tests on various synthetic data sets show that the algorithm is effective in retrieving teleseismic SH waveforms from complicated wave trains containing both S and ScS. Separation of waveforms for the 2008 Wenchuan earthquake with our algorithm clearly demonstrates the influence of ScS energy, suggesting necessity of recovering S waves.