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EFEITO DE RESERVATÓRIO DE APROVEITAMETO DE ÁGUA DA CHUVA SOBRE REDES DE DRENAGEM PLUVIAL / EFFECT OF RAINWATER HARVESTING RESERVOIRS OVER URBAN DRAINAGE NETWORKSHentges, Sara Ceron 28 August 2013 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The urban growth and the disordered occupation of cities have increased the frequency and severity of
flooding in urban areas, which occur mainly due to the modification on rainwater natural infiltration, as a result
of soil imperviousness increase. The use of compensatory techniques (CT) for stormwater control has been
encouraged through public polices, attempting to apply for sustainable solutions to mitigate the urbanization´s
impact. An alternative already widespread in some Brazilian cities is the use of micro reservoirs (MR), which
temporarily store volumes from impervious areas, and gradually emptying the water stored. Along this
requirement, implementation of Rainwater Harvesting Reservoirs (RHR) to non-potable purposes is often
encouraged in order to reduce the consumption of drinking water for less noble purposes, and to preserve the
fountainheads. Some bibliographies suggest that in addition to these benefits, the RHR can be considered a CT
also, once it stores the stormwater runoff, and therefore, in some cities where the MR is required, many buildings
are already using the RHR to replace it. However, there are not many conclusive studies related to the real
benefits and impacts that capturing rainwater and its use have on micro drainage networks, and specifically if
such technique can be considered as a compensatory one. Thus, the main objective of this research was to
evaluate whether RHR can be considered as an alternative to promote the quantitative stormwater control. For
that, a comparative analysis was made between the impact that RHR use generates on micro drainage flows and
networks, and the impact generated on a MR containing system. Such analysis was performed through a
modeling of a urban watershed from Porto Alegre / RS, with 977 ha, 30.720 standard lots and around 70 km of
micro drainage networks. The simulated MRs were designed according to the Decree No. 15.371/06 of the city
of Porto Alegre, which aim to control the runoff at the source and it resulted in volumes of 3.13 m³ and 3.75 m³
for rainfall project with return period of 5 and 10 years (CP-CP-TR5 and TR10), respectively, answering to the
allowable flow restriction at the lot outlet (VR = 0.624 L / s). The micro drainage networks were designed for
both situations, with and without MRs, for CP-TR5 and CP-TR10. For sizing of the RHRs a continuous
simulation of 12 years of precipitation data and demands series for non-potable uses data was performed, both
with time step equal 5 minutes, resulting in volumes of 5.000, 10.000 and 15.000 liters due to the achieved
service guarantee. These volumes of RHRs replaced the MRs and new modeling were performed considering
observed rainfall data real from the continuum time series. It was found that the RHRs were not effective to
maintain the VR at lots outlet, and the restriction value was exceeded for several times. For the simulated time
seriess only the volume of 750 m³ would be appropriate to ensure only one offense within 10 years of simulation.
That occurs because must have sufficient volume to store the expected drained volume, without spillage,
regardless of the reservoir storage condition. However, if there is a very large storage capacity and demands are
comparatively small, the reservoir does not empty. It was found, therefore, that exists an antagonism when trying
to use the RHR for two functions: runoff control and water supply for non-potable purposes demand, since the
attempt to ensure the fulfillment to the first function prevents the deployment of such large volumes.
Overtopping of RHRs to 12 critical simulated events committed the microdrainage networks capacity, generating
flooding in the streets along several drainage network ranges. Considering the same 12 critical events and MRs
in lots were identified only four overflowing and lower overflows, which ended up committing a lower extent of
drainage networks. Therefore, based on analysis of the continuous simulation with RHRs, it was found that it is
not possible to consider it an equivalent technique to the MRs for storm water runoff control, unless the
reservation volumes are extremely high, which would make its implementation on a few square meters lot
impossible. / O crescimento urbano e a ocupação desordenada das cidades têm aumentado a frequência e a severidade das
enchentes em áreas urbanas, que ocorrem, principalmente, devido à modificação nas condições naturais de infiltração
das águas pluviais, decorrentes do aumento da impermeabilização do solo. Em busca de soluções sustentáveis para
mitigar os impactos da urbanização, as políticas públicas vêm incentivando o uso de técnicas compensatórias (TC)
para o controle do escoamento superficial. Uma alternativa já difundida em algumas cidades brasileiras é o uso de
microrreservatório (MR), que armazena temporariamente os volumes oriundos do escoamento das áreas impermeáveis,
esvaziando gradativamente a água armazenada. Paralelamente a essa exigência, a implementação de reservatórios para
o aproveitamento da água da chuva (RAAC) com fins não potáveis vem sendo incentivada, com o intuito de reduzir o
consumo de água tratada para fins menos nobres e preservar os mananciais. Algumas bibliografias sugerem que além
desses benefícios, o RAAC pode ser considerado igualmente uma TC, já que armazenaria o escoamento pluvial, e por
essa razão, em algumas cidades onde o MR é exigido, muitas edificações já estão utilizando o RAAC em substituição a
este. No entanto, verifica-se uma falta de estudos conclusivos a respeito dos reais benefícios e impactos que a captação
da água da chuva e seu aproveitamento têm sobre as redes de microdrenagem pluvial e, especificamente, se esta
técnica pode ser considerada como compensatória. Assim, o principal objetivo desta pesquisa foi avaliar se os RAACs
podem ser considerados como medidas para o controle quantitativo do escoamento pluvial. Para isso, foi realizada uma
análise comparativa do impacto que a sua utilização gera sobre as vazões e redes de microdrenagem, com o impacto
gerado em um sistema com MR. A análise foi realizada mediante modelagem matemática de uma bacia hidrográfica
urbana da cidade de Porto Alegre/RS, com 977 ha, 30.720 lotes padrão e cerca de 70 km de redes de microdrenagem.
Os MRs simulados foram dimensionados de acordo com o Decreto n° 15.371/06 da cidade de Porto Alegre para o
controle do escoamento na fonte, resultando em volumes de 3,13 m³ e 3,75 m³, para chuvas de projeto com 5 e 10 anos
de período de recorrência (CP-TR5 e CP-TR10), respectivamente, atendendo à vazão de restrição permissível na saída
do lote (VR = 0,624 L/s). As redes de microdrenagem foram dimensionadas para as situações que contemplaram os
MRs e para a situação sem os MRs, para CP-TR5 e CP-TR10. Para o dimensionamento dos RAACs foi realizada uma
simulação contínua de 12 anos de dados de chuvas e série de demandas para fins não potáveis, ambas com intervalo de
tempo de 5 minutos, tendo sido determinados os volumes de 5.000, 10.000 e 15.000 litros como os mais adequados
para a edificação, em razão da garantia de atendimento atingida. Esses volumes de RAACs substituíram os MRs e
novas modelagens foram realizadas considerando tanto eventos de projeto, como as chuvas reais da série contínua.
Verificou-se que os RAACs não são eficientes na manutenção da VR na saída dos lotes, sendo que ao longo da série
história simulada a mesma foi infringida várias vezes. Para a série histórica simulada apenas um volume de 750 m³
seria adequado para garantir apenas uma infração em 10 anos da simulação. Isso ocorre porque deve haver volume de
espera suficiente para armazenar os volumes escoados, sem que haja vertimento, independentemente da condição de
armazenamento do reservatório; no entanto, se existe uma capacidade de armazenamento muito grande, e as demandas
são comparativamente pequenas, o reservatório não esvazia. Constatou-se, dessa forma, que existe um antagonismo
quando se pretende utilizar o RAAC para as duas funções: controle de escoamento superficial e garantia de
atendimento à demanda com fins não potáveis, visto que a tentativa de garantir o cumprimento da primeira função
inviabiliza a implantação de volumes tão grandes. O extravasamento dos RAACs para 12 eventos críticos simulados
comprometeu a capacidade das redes de microdrenagem, gerando armazenamento de água nas ruas ao longo de vários
trechos. Considerando os mesmos 12 eventos críticos e os MRs nos lotes foram identificados apenas 4
extravasamentos e menores vazões extravasadas, o que acabou comprometendo uma menor extensão das redes de
drenagem. Portanto, com base nas análises da simulação contínua com os RAACs, verificou-se que não é possível
considerá-lo uma técnica equivalente aos MRs para o controle do escoamento pluvial, a menos que os volumes de
reservação sejam extremamente elevados, o que tornaria impossível a sua implementação em um lote de poucos
metros quadrados.
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Variabilidade interanual do clima de ondas e sua influência no litoral Sudeste e Sul do Brasil / Interanual wave climate variability and its influence on the south and southeast coast of Brazil, numericalTalitha de Souza Lourenço 04 December 2012 (has links)
As ondas geradas por tempestades causam as alterações mais significativas na costa arenosa. Este trabalho avaliou a influência da variabilidade interanual do clima de ondas nos processos costeiros do litoral Sudeste e Sul do Brasil. O clima de ondas foi determinado a partir de resultados entre 1997 e 2010 do modelo numérico NOAA WAVEWATCH III (NWW3) com seis pontos de água profunda. O modelo numérico MIKE 21 SW foi utilizado para verificar o efeito destas ondas na Enseada de Massaguaçu (SP) e no trecho Sul de Imbituba (SC). Foram simuladas as direções de ondas mais frequentes e foi calculado o transporte longitudinal de sedimentos gerado por elas. As ondas do quadrante Sul foram mais energéticas e não foi identificado um padrão na variação interanual do clima de ondas. Em São Paulo, as direções de onda mais frequentes (Sul e Sul-Sudoeste) não geraram quantidade efetiva de transporte de sedimentos, e foram as ondas de Leste-Sudeste a Sudeste-Sul que geraram a maior quantidade de transporte longitudinal de sedimentos. Em Santa Catarina foram as ondas de Leste a Sul que geraram maior transporte longitudinal de sedimentos. / The coastal dynamics is mainly controlled by waves, being the energetic storm waves the most influential. This study aims to assess the wave climate influence on coastal processes in the South and Southeastern coast of Brazil. The wave climate was defined through NOAA WAVEWATCH III (NWW3) numerical model results for six offshore points, from 1997 to 2010. In order to propagate the waves onshore the Spectral Wave FM from MIKE 21 numerical model has been applied on Massaguaçu bay (SP) and Imbituba (SC). Most frequent storm waves have been simulated for each year and sector and sediment longshore transport along each sector was calculated. Waves from the South are the most energetic. There is no clear interanual pattern in the time-series. For SP, the most frequent directions (South and South-Southwest) do not generate considerable longshore sediment transport, with East-Southeast to Southeast-South waves generating most sediment transport, which was northwards for all beaches. In SC the sediment transport was northwards in Vila and Vila Nova beaches and southwards on Itapirubá beach, with waves from Eastern and Southern quadrants generating more longshore sediment transport.
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La forêt des Landes de Gascogne comme patrimoine naturel? Echelles, enjeux, valeurs. / The forest of Landes de Gascogne as a natural heritage ? Scales, stakes, valuesPottier, Aude, Marie-Emilie 08 December 2012 (has links)
Ce travail de thèse en Géographie Humaine a pour objectif d’identifier et d’analyser les valeurs qui font entrer le massif forestier des Landes de Gascogne dans un processus dit de patrimonialisation au travers des discours et actions de ses acteurs. Affecter des valeurs à un espace forestier, le patrimonialiser ne correspond plus simplement à la mise en place d’espaces protégés où le « exceptionnel » est adoubé. Le processus ne se définit plus par la simple protection officielle qui soustrait à l’action humaine des éléments jugés remarquables : des objets et des espaces de plus en plus communs et quotidiens sont également appropriés par des groupes sociaux variés tout autant spécialistes qu’ « amateurs ». Le massif forestier des Landes de Gascogne constitue, selon nous, un espace exemplaire pour traiter de cette appropriation d’un espace forestier « ordinaire », qui n’a, a priori, rien de « remarquable », du moins, selon les critères de la patrimonialisation institutionnelle. Forêt d’origine artificielle à vocation de production en grande majorité privée, le massif forestier landais a toujours été plus ou moins décrié pour sa gestion intensive remettant en cause sa capacité à être porteuse de valeurs autres qu’économique et pouvant aller jusqu’à remettre en question son statut de forêt. Pour autant, bien que la vocation productive de ce massif soit sa raison d’être, la forêt landaise est aussi porteuse de valeurs culturelles, naturalistes et sensibles qui la font entrer dans une volonté de préservation qui dépasse, et parfois se confronte, à sa simple importance économique. La dernière tempête Klaus de Janvier 2009, a permis d’à la fois révéler et catalyser ses valeurs qui, face à un tel bouleversement, s’exacerbent. Aborder la patrimonialisation de cet objet forestier à part entière, partagé entre nature et culture, permet ainsi de questionner l’idée même de patrimoine naturel et le processus qui le sous-tend. La thèse s’appuie sur l’analyse d’une centaine d’entretiens semi-directifs effectués auprès de différents acteurs du massif (sphère forestière privée et publique, élus, collectivités territoriale, Parc Naturel Régional, milieu associatif) et menés selon une double échelle d’analyse (de l’échelle « massif » à l’analyse plus localisée de quatre terrains d’étude). / This thesis in Human Geography aims to identify and analyze the values which imply an heritage process through the words and actions of its actors. To associate a forest with values, to launch an heritage process does not mean only to set it as a protected area where the exceptional character of this area is acknowledged. This process cannot be reduced to official protection, preserving from human activities some elements considered as remarkable: more and more common areas and elements are equally owned by different social groups, specialists just as much as amateurs. With this regards, the forest of Landes de Gascogne constitutes a good example of heritage process of a common and ordinary forest, with nothing “remarkable” at first sight, at least according to the usual criteria of institutional natural heritage. This artificial forest has a production purpose and is privatized for its vast majority. Therefore, this forest has always been more or less pointed out for its intensive exploitation, questioning its ability to circulate values outside economic ones, and even the legitimacy of its status as a forest. Nevertheless, and however its production purpose is its first determination, this forest is also carrying cultural, natural and sensible values which generate a willingness of preservation going beyond, or even confronting the simple economic concern. The last storm in January 2009, Klaus, enabled to unveil and catalyze those valued, which, in front of such an event, became clearer. To consider the heritage process of this forest as a whole, shared between nature and culture, also allows pondering over the idea of natural heritage in itself and the process behind. This thesis has been written thanks to the analysis of a hundred of semi-structured interviews of different actors of the forest (private and public areas, elected representatives, local communities, Regional Natural Parc, associations) and realized according to a double-scale analysis (from the whole forest scale to the more localized analysis of four different field studies).
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Práticas amorosas e normas socioculturais nas narrativas epistolares de Emilia e Joaquim Fontes (1890-1895)Matias, Joelma Dias 30 March 2017 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This research analyzed the practices of love in Sergipe in the XIX century based on the
experience of the couple Emilia and Joaquim Fontes, who bequeathed in the letters published
in the literary work Luz na tormenta (1948) by Emilia Fontes, the love story lived by the two.
We also understood how sociocultural rules controlled the practices of love in in the XIX
Brazil, as well as the impressions built by Brazilian society of that century on the norms that
regulated these practices. We also perceived femine behavior in the face of sociocultural rules
that controlled the practices of love in Brazil in the XIX century. We use as main source the
literay work Luz natormenta. We talk with the theories of Bourdieu (2002), Certeau (1994),
Elias (2005) and Pais (2007) to understand that everyday life is marked by the coexistence of
normativity and contingency, by a kind of unstable equilibrium of order. We found that
Sergipe Emilia Fontes had a good part of her life controlled by the forces of a patriarchal
power and, defying social conventions, opposed and resisted the rules that governed the
loving practices of her time, employing procedures that favored her loving relationship with
Joaquim. Therefore, we consider these positions of opposition and resistance to the norms
presented by Emilia as a vestige of change in the behavior of the Aracajunian society about
the norms that guided the practices of love in the late XIX century. / Esta pesquisa analisou as práticas amorosas em Sergipe em fins do século XIX, partindo da
experiência do casal Emilia e Joaquim Fontes, que legaram nas cartas editadas na obra Luz na
tormenta (1948) de Emilia Fontes, a história de amor vivida pelos dois. Compreendemos
ainda como as regras socioculturais controlavam as práticas amorosas no Brasil da década de
1890, além das impressões construídas pela sociedade brasileira desse século acerca das
normas que regulamentavam essas práticas. Percebemos, também, o comportamento feminino
diante das regras socioculturais que controlavam essas práticas amorosas no Brasil no século
XIX. Utilizamos como fonte principal a obra Luz na tormenta. Fazemos uso de conceitos
difundidos por Bourdieu (2002), Certeau (1994), Elias (2005) e Pais (2007) para entender que
o cotidiano é marcado pela coexistência da normatividade e da contingência, por uma espécie
de equilíbrio instável da ordem. Verificamos que a sergipana Emilia Fontes teve boa parte de
sua vida controlada pelas forças de um poder patriarcal e, desafiando as convenções sociais,
opôs-se e resistiu às regras que orientavam as práticas amorosas de sua época, empregando
procedimentos que favoreceram seu relacionamento amoroso com Joaquim. Portanto,
consideramos essas posturas de oposição e resistência às normas apresentadas por Emilia
como um vestígio de mudança no comportamento da sociedade aracajuana acerca das normas
que orientavam as práticas amorosas no final do século XIX.
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Análise da eficiência de métodos de controle de Enchentes na atenuação de picos de cheias utilizando o modelo computacional SWMM Storm Water managemente model / Analysis of the efficiency of flood control methods for the attenuation of peak flow using the SWMM - Storm water management modelSILVA, Karla Alcione da 31 August 2007 (has links)
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Previous issue date: 2007-08-31 / This research presents an evaluation of the eficiency of four flood control measures applied to an
urban basin in the city of Goiânia, State of Goiás, Brazil. Goiânia shows frequent flooding
problems. The following factors have been identified as causes of the floodings: (1) significant
number of impervious areas (2) lack of green areas, (3) insuficient capacity of the pipe network
to convey the produced water volume. Small detention basins, infiltration trenches and the
increase of permeable areas (30-50%) within parcels have been evaluated as flood control
measures as well as the use of the Lago do Bosque dos Buritis as a detention basin. For this
purpose, the Stormwater Management Model SWMM has been applied for evaluating 11
hypothetic management measures in the water basin. The later control measures were evaluated
individually as combined. In determining the impervious area index of the studied area, field
visits have been carried out, which showed high imperviousness. (86.16%). A synthetic rainfall
time series, derived from the equation proposed by Costa e Brito (1999) with recurrence of 2
years, has been used in the simulations. Horton`s equation was applied to represent infiltration
with parameters presented in Moura (2005). The scenario which combines the use of infiltration
trenches and the increase of pervious areas to 50% has shown to be the best solution in reducing
peak flow with 43% eficiency. On the other hand, the scenario using detention basins presented
the smallest efficiency (3%). / O presente trabalho apresenta a avaliação da eficiência de quatro métodos de controle de
enchentes em uma bacia urbana localizada na cidade de Goiânia, que apresenta graves problemas
de inundação. Estes alagamentos devem-se a alguns fatores que foram levantados, tais como:
muitas áreas impermeabilizadas, poucas áreas verdes e rede com dimensões pequenas e
insuficientes para o escoamento de todo o volume produzido. Foram analisadas a implantação de
microservatórios de detenção, trincheira de infiltração, o aumento da área permeável no interior
do lotes (de 30% e 50%) e o uso dos lagos do Bosque dos Buritis como dispositivo de controle.
Para tanto, procederam-se simulações no modelo computacional SWMM Storm Water
Management Model em que foram avaliados 11 cenários hipotéticos na bacia, que consistiram
na aplicação dos dispositivos de forma individual e em conjunto. Para a determinação do índice
de impermeabilização da área estudada foi necessário realizar um levantamento em uma área
amostra, o qual demonstrou uma média de 86.16% de impermeabilização em cada lote. A
precipitação utilizada foi uma série sintética, determinada por meio da equação de chuva
desenvolvida por Costa e Brito (1999) com tempo de recorrência adotado de 2 anos. Para
representar a infiltração, optou-se por trabalhar com a equação de infiltração de Horton, segundo
os parâmetros de Moura (2005). O cenário simulado com a implantação de trincheira de
infiltração e o aumento da área permeável em 50% apresentou aproximadamente 43% de
eficiência na redução da vazão de pico, indicando que essa poderia ser a melhor solução para o
problema analisado, enquanto que o cenário com microreservatórios apresentou a menor
eficiência, aproximadamente 3%.
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Prevalência de tempestade elétrica em pacientes chagásicos portadores de cardioversor desfibrilador implantável / Prevalence of electrical storm in patients Chagas patients with CDILima , Antônio Malan Cavalcanti 12 December 2011 (has links)
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Previous issue date: 2011-12-12 / Background: Chagas’s heart disease remains a major public health problem in Brazil. Sudden death is the leading cause of decease, because of that, the implantable cardioverter defibrillator (ICD) has become an important therapeutic option in this disease. Objective: To define the prevalence and predictors of electrical storm (ES) in patients with Chronic Chagas Heart Disease (CCh) with an ICD. Methods: We retrospectively studied 81 consecutive patients with CCh in whom an ICD was implanted between January 2004 to December 2007, with a mean follow up of 45,9 ± 15 months. Patients were classified into two groups according to the presence of ES episodes. We compared baseline and funcional characteristics. p values less than 0,05 were considered statistically significant. Results: Thirty five patients (43,2%) developed TE during follow up. By univariate analysis, QRS width ≥ 150 ms (p=0,001), previous pacemaker (p=0,001), ventricular tachycardia (VT) for indication of ICD (p=0,001) and cumulative percent ventricular pacing (C%VP) > 40%/80%) were all predictors of TE. However, by multivariate analysis only the indication of ICD for VT (odds ratio (OR) = 9.16, 95% CI: 1.98 to 42.78, p = 0.005) and C%VP > 40%/80% (OR = 6.30, 95% CI: 1.56 to 25.49, p = 0.010) were independent predictors of TE. Conclusion: 1- ES is very frequent in subjects with CCh and ICD; 2- Indication of ICD for VT and C%VP > 40%/80% were independent predictors of TE. / Fundamento: A Cardiopatia Chagásica ainda é um importante problema de saúde pública no Brasil. A morte súbita é a principal causa de óbito, por isto, o cardioversor desfibrilador implantável (CDI) tornou-se importante opção terapêutica nesta doença. Objetivos: Avaliar a prevalência e fatores preditores da tempestade arritmogênica ou elétrica (TA ou TE) em pacientes chagásicos portadores de CDI. Metodologia: Estudo retrospectivo de uma coorte de 81 pacientes chagásicos submetidos a implante de CDI entre Janeiro de 2004 a Dezembro de 2007, com seguimento médio de 45,9 ± 15 meses.Os pacientes foram classificados em dois grupos de acordo com a presença ou não de TE. Comparou-se as características basais e funcionais da amostra utilizando-se testes estastísticos (t student, qui-quadrado e, quando necessário, Fisher). Resultados: A idade foi de 57,0 ± 9,5 anos, sexo masculino 60 (74,1%), a fração de ejeção (FE) média foi de 43,8 ± 7,6. Dos 81 casos da amostra, 35 (43,2%) apresentaram pelo menos um episódio de TE. Estes tiveram um total de 378 TE com média de 10,8 ± 11,6. Em análise univariada, identificou-se que a indicação do CDI por taquicardia ventricular sustentada espontanea (TVSE) (p=0,001), duração do QRS (dQRS) ≥ 150ms (p= 0,001), ser portador de marcapasso (MP) (p=0,001) , percentagem de estímulo de ventrículo direito (PEVD) > 40%/80% (p= 0,001) e classe funcional (CF) final III/IV (p= 0,015), foram fatores preditores de TE nesta coorte. Porém, a análise multivariada demonstrou que apenas a indicação de CDI por TVSE ( odds ratio (OR)= 9,16; IC 95%: 1,98- 42,78; p= 0,005) e PEVD > 40%/80% ( OR=6,30; IC 95%: 1,56-25,49; p=0,010 ) foram fatores preditores independentes para TE. Conclusão: Nos pacientes chagásicos portadores de CDI, houve elevada prevalência de TE (43,3%). Os fatores preditores independentes para TE foram: TVS (TVSE) prévia e PEVD > 40%/80%.
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Dinâmica sedimentar e resiliência às marés meteorológicas em ambientes costeiros da baixada santista: abordagem numérica / Storm surge resilience and sedimentar dynamic in Santos\'s coastal environment: numerical approachTito Conte 14 October 2016 (has links)
Dentre os ambientes costeiros, os estuários são as principais fontes de sedimento para os oceanos. Sua dinâmica sensível é amplamente suscetível a modificações de origem natural e antrópica impactando no balanço sedimentar destes ambientes. O presente trabalho busca compreender a importância da maré meteorológica causada por frentes frias sobre os processos sedimentares do complexo estuarino de Santos aplicando o modelo numérico XBeach com três cenários. O primeiro foi forçado apenas pela maré astronômica outro representando uma condição de frente fria média e um terceiro representando uma frente fria extrema. Buscou-se detectar as frentes utilizando dados de reanálise do NCEP/NCAR. Foram extraídos os cinco dias mais intensos das frentes escolhidas e aplicaram-se ao inicio da série de dados de input do modelo para os ensaios numéricos. Os resultados permitiram compreender que os sistemas frontais atuam como agentes essenciais no balanço sedimentar tendo um papel erosivo compensando os processos deposicionais atuantes no período sem frentes. Frentes muito intensas agravam as feições erosivas e deposicionais, desbalanceando o sistema além da sua capacidade de recuperação. / Among the coastal environments, the estuaries are the main sediment source for oceans. Its sensible dynamic is widely susceptible to changes of natural and anthropogenic impacts the sediment balance of those environments. This work applies the Xbeach numerical model in Santos estuary to understand the storm surges forced by cold fronts on the sediment transport through three scenarios. The first scenario input was astronomic tide sea surface high, the second scenario input was the median cold front and the last scenario input was an extreme cold front. To get the cold front condition we use the NCEP/NCAR reanalysis data. We applied the five most intense days from each cold front condition in the beginning astronomic tide series. With the numerical model results we could understand the erosive action from the cold fronts and how it compensates the depositional period without any cold fronts. The extreme cold fronts intensify the depositional/erosion process unbalancing the system beyond the resilience capacity.
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Evolution des composantes du niveau marin à partir d'observations de marégraphie effectuées depuis la fin du 18ème siècle en Charente-Maritime / Changes in sea level components from tide gauge data since the end of the 18th century along the Charente-Maritime French Atlantic coastGouriou, Thomas 26 March 2012 (has links)
Les estimations de la remontée générale du niveau de la mer, de l’ordre de 17 ± 2 cm sur le siècle dernier, masquent une réalité très variable d’une région à l’autre. Qu’en est-il du littoral charentais ? Des séries temporelles de plus de 40-50 ans sont souvent indispensables pour tirer des tendances fiables à long terme sur les composantes du niveau marin : niveau moyen de la mer, ondes de marée et effets météorologiques. Or, de nombreux lots de mesures marégraphiques du littoral charentais « sommeillaient » dans les centres d’archive français, i.e. : La Rochelle-Vieux port (1775-1892), La Rochelle-La Pallice (1885-auj.), île d’Aix (1824-auj.), fort Enet (1859-1873), fort Boyard(1873-1909) et Cordouan (1812-1994). Les objectifs de nos travaux de recherche étaient multiples : inventorier,sauvegarder et numériser des lots de mesures historiques du niveau marin, puis construire des séries temporelles recomposées à partir de ces lots de mesures hétérogènes, temporellement et spatialement, et enfin les exploiter pour mieux décrire et comprendre l’évolution à long terme du niveau de la mer. La qualité des trois séries construites (LaRochelle : 1775-auj. ; Aix-Enet-Boyard : 1824-auj. ; et Cordouan : 1812-1994) a ensuite été éprouvée en détail afin d’évaluer le niveau de précision de notre reconstruction. A partir de ces séries inédites, nous avons pu étudier l’évolution des composantes du niveau marin. Suite à ces travaux, nous fournissons un inventaire le plus exhaustif possible détaillant les mesures de 25 observatoires de Charente-Maritime, de 1775 à aujourd’hui. Les données des séries temporelles ainsi que des éléments permettant d’apprécier leur qualité seront bientôt disponibles en ligne sur REFMAR (refmar.shom.fr), SONEL (www.sonel.org) et au PSMSL (www.psmsl.org). Nos résultats positifs nous ont permis de reconstruire une série encore plus globale, celle du pertuis d’Antioche, à partir des moyennes mensuelles du niveau marin des séries de La Rochelle et d’Aix-Enet-Boyard. Parmi les résultats marquants obtenus,le niveau moyen de la mer s’est élevé de +1,38 ± 0,08 mm/an dans le pertuis d’Antioche sur la période 1860-2010.Ce résultat est cohérent avec Liverpool (+1,2 ± 0,1 mm/an sur la période 1858-1997 [Woodworth, 1999a]) et avec les récents résultats suggérant que l’élévation du niveau marin sur les côtes atlantiques européennes est moins importante qu’au niveau mondial (+1,7 ± 0,3 mm/an sur la période 1870-2004 [Church & White, 2006]). / Global sea level rise, which is estimated at 17 ± 2 cm over the last century, does not reflect the differences of the sealevel evolution between places across the world. What is the situation along the Charente-Maritime French Atlanticcoast? Time series covering a period of at least 40-50 years are vital to establish reliable long-term trends of sealevel components: mean sea level, tidal constituents and meteorological effects. Many tide gauge data sets of the Charente-Maritime coast have recently been rediscovered in archives: La Rochelle-Vieux port (1775-1892), La Rochelle-La Pallice (1885-today), île d’Aix (1824-today), fort Enet (1859-1873), fort Boyard (1873-1909) and Cordouan (1812-1994). The aims of this thesis were firstly to inventory, to rescue and to digitize historical sea leveldata sets. Secondly, those data sets were put back together in order to construct continuous time series, which have been analysed and led to a better description of long-term sea level changes. In this way, three time series were constructed (La Rochelle: 1775-today; Aix-Enet-Boyard: 1824-today; and Cordouan: 1812-1994) and have been deeply examined to assess the construction validity and quality. From these new time series, we could estimate changes of sea level components. Thanks to this research work, we have been able to provide an inventory as exhaustive as possible, with detailed measurements of twenty five Charente-Maritime’s stations from 1775 to nowadays. All those data will be soon available on REFMAR (refmar.shom.fr), SONEL (www.sonel.org) and PSMSL (www.psmsl.org) websites. From those positive results, we have been able to reconstruct a more global time series (Pertuis d’Antioche) from the monthly mean sea levels of La Rochelle and Aix-Enet-Boyard. Among our results, we can high light that the mean sea level trend on Pertuis d’Antioche is estimated at +1.38 ± 0.08 mm/year, from 1860 to 2010. This result is consistent with Liverpool’s trend (+1.2 ± 0.1 mm/year from 1858 to 1997[Woodworth, 1999a]) and also with recent results suggesting that sea level rise along the European Atlantic coasts isslower than global sea level rise (+1.7 ± 0.3 mm/year from 1870 to 2004 [Church & White, 2006]).
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Impact des processus humides sur les dépressions des latitudes tempérées / Impact of moist processes on midlatitude cyclonesCoronel, Benoît 25 November 2015 (has links)
Les objectifs de cette thèse sont d'analyser l'influence des processus humides sur les dépressions des moyennes latitudes en s'intéressant plus particulièrement aux déplacements des dépressions et à la formation des vents forts près de la surface. Ces recherches ont été effectuées à l'aide de simulations idéalisées du modèle de méso-échelle Méso-NH. La première étude s'est focalisée sur l'effet des processus humides sur le déplacement des dépressions dans la direction perpendiculaire à l'axe du courant-jet, c'est à dire principalement le déplacement vers les pôles. Le mécanisme expliquant ce déplacement est dû à l'advection non-linéaire de la dépression de surface par les anomalies cyclonique et anticyclonique d'altitude se trouvant de part et d'autre de la dépression de surface. En présence d'humidité, l'anomalie anticyclonique d'altitude se renforce du fait du dégagement de chaleur latente dans les zones d'ascendances, et ainsi le déplacement perpendiculairement à l'axe du jet et vers les pôles s'accélère. On montre aussi que le déplacement vers l'est des dépressions s'accélère en incluant les processus humides. La seconde étude porte sur la formation des vents forts près de la surface et notamment sur ce qu'on appelle les "sting jets". Les "sting jets" sont des jets dont les masses d'air associées descendent rapidement du milieu de la troposphère au niveau de la tête du nuage jusqu'au sommet de la couche limite et peuvent déclencher des vents dévastateurs en surface. Ceux-ci se forment lorsque le front chaud se déplace à l'arrière de la dépression et qu'une fracture frontale apparaît. Les simulations montrent que, lorsqu'une dépression traverse l'axe du courant-jet de son côté chaud à son côté froid, le retour en arrière du front chaud se produit tandis qu'une dépression naissant côté froid du courant-jet possède un front chaud beaucoup moins actif. Ainsi, la formation d'un " sting jet " n'apparaît que dans le premier cas , moyennant une résolution verticale élevée. C'est la présence d'un forçage géostrophique dans un environnement neutre vis-à-vis de l'instabilité symétrique qui facilite la descente des masses d'air et la formation du " sting jet ". / The objective of this thesis is to analyze the influence of moist processes on mid-latitude cyclones, and specifically the tracks of cyclones and the formation of strong winds near the surface. These researches have been made using idealized simulations of the mesoscale model Méso-NH. The first study focused on the effects of moist processes on the motion perpendicularly to the zonal jet axis, poleward. The main mechanism explaining this motion involves the nonlinear advection of the surface cyclone by the upper-level cyclonic and anticyclonic perturbations located on both sides of the surface cyclone. In the presence of humidity, the upper-level anticyclonic anomaly strengthens due to the latent heat release in the ascent zones, and the poleward motion is reinforced. The eastward motion of the cyclone is also reinforced with the inclusion of moist processes. The second study focuses on the formation of near-surface strong winds which are triggered by the so-called " sting-jets ". These jets correspond to descending air masses from the mid-troposphere near the cloud head down to the top of the boundary layer, and can trigger devastating surface winds. In the case where synoptic perturbations are initialized south of the baroclinic zonal jet, the bent-back warm front phase occurs, whereas when they are initialized on the zonal jet axis, the surface cyclone has a less active warm front. Thus, the formation of a sting-jet only occurs in the first case, and with a high vertical resolution. It is the geostrophic forcing in a globally neutral environment relative to conditional symmetric instability which facilitates the airstreams descent and the formation of the sting-jet.
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Analyse du bruit microsismique associé à la houle dans l'océan Indien / Analysis of the swell-related microseismic noise in the Indian oceanDavy, Céline 26 November 2015 (has links)
Les données sismologiques enregistrées sur les îles océaniques offrent l'opportunité d'analyser la houle via sa signature dans le "bruit" microsismique. Nous avons d'abord analysé les sources de bruit « secondaires », qui sont générées par l'interaction entre des vagues de même période dans une tempête, un cyclone ou par le phénomène de réflexion des vagues sur la côte. L'analyse des « microséismes secondaires », à l'échelle du bassin océanique, permet d'assurer un suivi spatio-temporel de la source qui les génère, même si elle est distante de plusieurs milliers de km des stations sismiques d'enregistrement. À plus long terme, leur étude permet d'assurer un suivi climatique global de l'activité des vagues dans une région donnée. Nous avons également étudié les sources de bruit « primaires », qui sont générées par l'interaction directe de la houle avec la côte. L'analyse des « microséismes primaires » permet de caractériser la houle localement par son amplitude, sa période et sa direction de propagation. Il est alors possible d'utiliser un capteur sismique comme substitut d'un houlographe. Dans le contexte des îles Éparses et de La Réunion, nous avons étudié plusieurs épisodes de houles extrêmes qui les touchent fréquemment et qui peuvent avoir d'importantes répercutions sociales ou environnementales. Enfin, en utilisant un réseau temporaire de stations sismologiques à La Réunion, nous avons analysé les variations du niveau de bruit microsismique pour caractériser l'impact des houles extrêmes sur les différentes façades de l'île. Cette étude permet d'identifier les sites les plus exposés aux vagues qui présentent un intérêt pour la récupération de cette énergie renouvelable encore trop sous-exploitée. / Seismic data recorded on oceanic islands can be used to analyze the swell through its signature in the microseismic noise. We first analysed the "secondary" noise sources, which are generated by the interaction of ocean waves with similar period within a storm, a cyclone or by the reflection phenomena off the coast. By analyzing secondary microseisms at the scale of the oceanic basin, we first performed a spatio-temporal tracking of the source, even localized thousands km off the recording seismic stations. Secondly, in the long-term, they can be used to follow the global climate change related to the ocean waves activity in a specific region. We also studied the "primary" seismic noise sources, which are created by the direct interaction of ocean waves with the coast. By analyzing these primary microseisms, we succeeded to characterize ocean waves locally in terms of amplitude, period, and, sometimes, direction of propagation. This showed that it is possible to use a seismic station as an ocean waves gauge to get precious swell data, particularly in remote and poorly instrumented areas. In the context of the Iles Éparses and of La Réunion Island, we studied a few extreme swells, which occur there frequently and can have strong social and environmental consequences. Finally, by using a temporary network of seismic stations installed in La Reunion, we studied the spatial variations of the seismic noise level across the island to characterize the swell impact on the different coasts. This study enables us to identify the most exposed spots to the swell, which may be attractive for generating renewable energy with this powerful resource yet underexploited.
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