• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 29
  • 1
  • 1
  • 1
  • Tagged with
  • 37
  • 8
  • 8
  • 8
  • 5
  • 5
  • 5
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 3
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Caracterização química e efeitos farmacológicos de produtos derivados de Palicourea rigida Kunth (Rubiaceae)

Pinheiro, Rafael Pimentel 30 July 2015 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-03-10T14:07:49Z No. of bitstreams: 1 rafaelpimentelpinheiro.pdf: 5642312 bytes, checksum: c0018e11016a4083a03c156be84fe1ad (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-03-13T19:16:19Z (GMT) No. of bitstreams: 1 rafaelpimentelpinheiro.pdf: 5642312 bytes, checksum: c0018e11016a4083a03c156be84fe1ad (MD5) / Made available in DSpace on 2017-03-13T19:16:19Z (GMT). No. of bitstreams: 1 rafaelpimentelpinheiro.pdf: 5642312 bytes, checksum: c0018e11016a4083a03c156be84fe1ad (MD5) Previous issue date: 2015-07-30 / Palicourea rigida Kunth, pertencente à família Rubiaceae, tem sido utilizada na medicina popular para o tratamento de inflamações e infecções do trato urinário, do aparelho reprodutor feminino e para doenças da pele. Do ponto de vista químico, triterpenos, iridoides, flavonoides e alcaloides têm sido identificados na espécie. O objetivo do presente trabalho foi realizar uma caracterização química e avaliar as atividades anti-inflamatória tópica e cicatrizante de P. rigida. Folhas secas e pulverizadas foram extraídas em etanol P.A. por maceração estática seguida de rota-evaporação para obtenção do extrato etanólico (EEPR). EEPR foi submetido à partição líquido/líquido, adquirindo as frações hexânica, diclorometânica, em acetato de etila e butanólica. EEPR foi analisado por CLUE-UV-EM, enquanto a fração hexânica por CG-EM. A fração em acetato de etila foi fracionada por cromatografia em coluna de Sephadex LH-20 e a substância isolada foi elucidada por RMN 1H e 13C e espectrometria de massas. A partir de EEPR, foi desenvolvido uma formulação de creme à base Lanette® (cEEPR). A atividade antiinflamatória tópica de EEPR foi avaliada pelos modelos de edema de orelha em camundongos Swiss empregando óleo de cróton, ácido araquidônico, capsaicina e fenol. A atividade cicatrizante de EEPR e cEEPR foi investigada em ratos Wistar através do modelo de lesões por excisão cutânea. Análises histopatológicas e as atividades das enzimas mieloperoxidase (MPO) e N-acetil-β-d-glucoronidase (NAG) foram também determinadas. Loganina e quercetina 3-6- O-acetil-β-glicosídeo foram identificadas no EEPR por CLUE-UV-EM, enquanto ácido palmítico, fitol, ácido linoleico, esqualeno, gama tocoferol, vitamina E, campesterol, estigmasterol e gama sitosterol foram caracterizadas na fração hexânica por CG-EM. A partir da fração em acetato de etila, o flavonoide quercetina 3-O-β-D-glicosídeo foi isolado e sua estrutura elucidada. EEPR apresentou atividade anti-inflamatória tópica nos diferentes modelos através da redução da massa e espessura do edema, assim como pela diminuição do processo inflamatório observado pelas análises histopatológicas e inibição das atividades de MPO e NAG. EEPR e cEEPR demonstraram atividade cicatrizante pela diminuição da área da lesão e aumento do grau de contração, bem como pela estimulação do processo de cicatrização e redução das atividades de MPO e NAG. Os resultados indicam que P. rigida é rica em substâncias bioativas que podem ser responsáveis pelas atividades anti-inflamatória e cicatrizante. / Palicourea rigida Kunth, belonging to the Rubiaceae family, has been used in folk medicine for the treatment of inflammation and infections of the urinary tract, female reproductive tract and skin conditions. From the chemical point of view, triterpenes, iridoids, flavonoids and alkaloids have been identified in species. The aim of this study was to perform a chemical characterization and evaluate the topical anti-inflammatory and wound healing activities of P. rigida. Dried and powdered leaves were extracted in ethanol PA by static maceration followed by rota-evaporation for obtaining ethanol extract (EEPR). EEPR was subjected to partition liquid/liquid to obtain the hexane, dichloromethane, ethyl acetate and butanol fractions. EEPR was analyzed by UPLC-UV-MS, while the hexane fraction by GC-MS. The ethyl acetate fraction was separated by column chromatography with Sephadex LH-20 and the isolated compound was elucidated by 1H and 13C NMR and mass spectrometry. From the EEPR, a dermatological formulation was developed using the cream-based Lanette® (cEEPR). The topical anti-inflammatory activity of EEPR was evaluated by the ear edema models in mice Swiss using croton oil, arachidonic acid, capsaicin and phenol. The wound healing activity of EEPR and cEEPR was investigated in Wistar rats through the model of skin lesions. Histopathological analysis and activity of the enzyme myeloperoxidase (MPO) and N-acetyl- β-D-glucuronidase (NAG) were also determined. Loganin and quercetin 3-6-O-acetyl-β- glucoside were identified in EEPR by UPLC-UV-MS, while palmitic acid, phytol, linoleic acid, squalene, gamma tocopherol, vitamin E, campesterol, stigmasterol and sitosterol were characterized in the hexane fraction by GC-MS. From the fraction in ethyl acetate, the flavonoid quercetin 3-O-β-D-glucoside was isolated and its structure elucidated. EEPR showed topical anti-inflammatory activity in different models by reducing the the mass and thickness of the edema, as well as through the decrease in the inflammatory process observed by histopathological analysis and inhibition of the MPO and NAG activities. EEPR and cEEPR demonstrated wound healing activity by decrease the area of lesion and increase the contraction degree, as well as stimulate the healing process and reduce the MPO and NAG activities. The results indicate that P. rigida is rich in bioactive substances which may be responsible for the anti-inflammatory and wound healing activities.
22

Caractérisation structurale et fonctionnelle des métabolites de l'algue verte Ulva Rigida au moyen d'une approche protéomique / Structural and functional characterization of the metabolites of the green alga Ulva rigida using a proteomic approach

Zehlila, Amel 30 June 2017 (has links)
Les molécules naturelles de différentes origines et essentiellement celles issues des algues marines conçoivent une panoplie de principes bioactifs naturels à fort potentiel thérapeutique. Actuellement, plusieurs recherches sont consacrées à l’isolement de nouveaux composés bioactifs à partir des ressources marines qui renferment des effets bénéfiques prometteurs pour la santé. Parmi les ressources marines, les composés bioactifs présents dans de nombreuses espèces d’algues ont des propriétés nutritionnelles et pharmaceutiques particulièrement intéressantes. Cette thèse s’intéresse aux effets bénéfiques de l’algue Ulva rigida. Elle concerne plus particulièrement les activités des extraits protéiques de l’algue verte Ulva rigida. En effet, dans la présente étude, nous avons étudié l'effet préventif d'un extrait de protéine (PE) d'Ulva rigida contre les dommages cellulaires induits par les UVB. Nous avons démontré qu'un traitement des astrocytes corticaux avec 50 μg de PE induit un fort effet glioprotecteur et supprime les effets nocifs des rayonnements UVB, augmentant en particulier la viabilité cellulaire. D’autres essais supplémentaires nous ont permis d’affirmer que cet extrait stimule l'activité de la catalase et de la superoxyde dismutase et inhibe la production de marqueurs de stress, tels que le H2O2 ou la peroxydation lipidique. Par ailleurs, la digestion protéolytique ou le traitement thermique de l'extrait d'algue ont inhibé cet effet préventif, plaidant pour le rôle prédominant de la fraction protéique. Par la suite, des études protéomiques ont permis d'identifier plusieurs protéines de l'extrait, parmi lesquelles la calmoduline s'est avérée représenter un contributeur important aux activités de protection observées à la fois sur des cultures d’astrocytes que sur des neurones en grain. / Natural molecules from different origins present a high therapeutic potential. Among them, molecules extracted from marine algae are particularly interesting. Several studies are currently being devoted to the isolation of new bioactive compounds from marine resources that have promising health benefits. Among the marine resources, the bioactive compounds present in many species of algae have particularly interesting nutritional and pharmaceutical properties. This thesis deals with the beneficial effects of the alga Ulva rigida. It relates more particularly to the activities of the protein extract of the green alga Ulva rigida. In this study, we studied the preventive effect of a protein extract (PE) of Ulva rigida against UVB-induced cell damage. We have demonstrated that treatment of cortical astrocytes with 50 μg of PE induces a strong glioprotective effect and suppresses the harmful effects of UVB radiation, in particular increasing cell viability. Other extra tests allowed us to say that this extract stimulates the activity of catalase and superoxide dismutase and inhibits the production of stress markers such as H2O2 or lipid peroxidation. Moreover, the proteolytic digestion or the heat treatment of the algal extract inhibited this preventive effect, arguing for the predominant role of the protein fraction. Subsequently, proteomic studies have identified several proteins in the extract, of which calmodulin has been shown to be an important contributor to the protective activities observed on both astrocyte and neuron cultures.
23

CaracterizaÃÃo quÃmica, atividade antioxidante e seguranÃa de uso de sementes de Licania rigida Benth / Chemical, antioxidant activity and safety Licania seed use rigid Benth

Igor Parra Pessoa 24 April 2015 (has links)
CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Radicais livres tÃm sido associados à etiologia e à progressÃo de diversas patologias crÃnico-degenerativas, e constituem um dos fatores de deterioraÃÃo da qualidade de alimentos. Existe um crescente interesse em encontrar fontes naturais e seguras de antioxidantes capazes de neutralizar esses agentes nocivos sem alterar de forma negativa caracterÃsticas sensoriais dos alimentos. Dentro deste contexto, extratos de plantas ricos em polifenÃis tÃm sido investigados para esse fim. Este estudo objetivou caracterizar a composiÃÃo fenÃlica do extrato etanÃlico (EELr) e fraÃÃes derivadas de sementes de Licania rigida (aquosa, FALr; metanÃlica, FMLr; acetato de etila, FAELr; clorofÃrmica, FCLr; hexÃnica, FHLr), estimar a capacidade antioxidante total e, paralelamente, avaliar a seguranÃa de uso atravÃs de testes de toxicidade in vitro e in vivo. Foram detectadas atravÃs de prospecÃÃo fitoquÃmica qualitativa trÃs classes de metabÃlitos secundÃrios no extrato: taninos, flavonoides e saponinas. AlÃm disso, foi determinada a quantidade de fenÃis totais, flavonoides e taninos do EELr e das fraÃÃes FAELr, FALr e FMLr (de 3,815 a 6,452; 0,006 a 0,135; 0,147 a 0,294 equivalentes em micrograma de Ãcido gÃlico, quercetina e Ãcido tÃnico por grama de amostra, respectivamente). Onze compostos fenÃlicos distintos, classificados como Ãcidos fenÃlicos e flavonoides, foram identificados via CLAE. O Ãcido cafeico e o Ãcido clorogÃnico foram os majoritÃrios dentre os Ãcidos fenÃlicos, e a quercetina e o kaempferol dentre os flavonoides. Em geral, o EELr, FALr, FAELr e FMLr mostraram atividade antioxidante no ensaio DPPH com CN50 variando de 2,79 a 196,6 Âg/mL. Em relaÃÃo ao ensaio de inibiÃÃo da peroxidaÃÃo lipÃdica (usando TBARS), a FALr foi capaz de prevenir peroxidaÃÃo lipÃdica tanto em condiÃÃes normais como na presenÃa de indutor de estresse (ferro). Houve tambÃm uma clara relaÃÃo positiva entre o conteÃdo de taninos das amostras e o bom desempenho nas atividades antioxidantes. Flavonoides como a quercetina, quercitrina e catequina correlacionaram-se positivamente com o resultado do teste DPPH e do TBARS sem induÃÃo de estresse por ferro. Jà os Ãcidos fenÃlicos, como Ãcido clorogÃnico, mostraram-se mais importantes quando o ferro foi usado. EELr, FALr, FAELr e FMLr mostraram perfil fenÃlico promissor com potente atividade antioxidante total. A composiÃÃo natural das sementes dessa planta pode ser explorada na indÃstria farmacÃutica para produzir nutracÃuticos. De forma geral, o EELr apresentou baixa ou nenhuma toxicidade de acordo com os ensaios utilizados. No entanto, abordagens mais sensÃveis como a toxicogenÃmica e ensaios de toxicidade crÃnica em animais devem ser feitos a fim de garantir a sua seguranÃa de uso. / Free radicals have been associated to the etiology and the progression of various chronic-degenerative diseases, and constitute one of the factors that affect food quality deterioration. There is a growing interest in finding natural and safe sources of antioxidants that are able to neutralize those damaging agents without negatively altering food sensorial characteristics. In this context, plant extracts rich in polyphenols have been investigated to this end. This study aimed to characterize the phenolic composition of the ethanolic extract (EELr) and derived fractions from Licania rigida seeds (aqueous, FALr; methanol, FMLr; ethyl acetate, FAELr; chloroform, FCLr; hexane, FHLr), to estimate the total antioxidant capacity and, at the same time, to evaluate the safe use through in vitro and in vivo toxicity tests. Phytochemical screening has detected three secondary metabolite classes from EELr: tannins, flavonoids and saponins. Moreover, it was determined the amount of total phenols, flavonoids and tannins (from 3.815 to 6.452; 0.006 to 0.135; 0.147 to 0.294 gallic acid, quercetin and tannic acid equivalents in micrograms per gram of sample, respectively). Eleven distinct phenolic compounds, classified as phenolic acids and flavonoids, were identified by HPLC. The caffeic and chlorogenic acid were the major compounds among the phenolic acids, and quercetin and kaempferol among the flavonoids. In general, the EELr, FALr, FAELr and FMLr showed antioxidant activity towards the DPPH free radical with SC50 ranging from 2.79 to 196.6 Âg/mL. Regarding the inhibition of lipid peroxidation assay (using TBARS), FALr was capable of preventing lipid peroxidation both in normal conditions and in the presence of stress inducer (iron). There was a clear positive relation between the samplesâ tannin content and a good performance in the antioxidant activities. Flavonoids as quercetin, quercitrin and catechin correlated positively with the results of DPPH assay and TBARS assay without iron as a stress-inducer. In the other hand, the phenolic acids, such as chlorogenic acid, showed to be more preponderant when iron was used. EELr, FALr, FAELr and FMLr showed a promising phenolic profile with potent antioxidant activity. The natural composition of L. rigida seeds can be explored in the pharmaceutical industries to produce nutraceuticals. Generally, the EELr presented low toxicity accordingly to the assays used. Nevertheless, more sensitive approaches like toxicogenomics and non-acute toxicity assays with animals must be performed to guarantee its safe use.
24

Atividade antimicrobiana e antioxidante de Licania rigida e Turnera ulmifolia

Morais, Leandro Vin?cius Fernandes de 30 March 2015 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-08-16T21:49:55Z No. of bitstreams: 1 LeandroViniciusFernandesDeMorais_DISSERT.pdf: 1776137 bytes, checksum: 5be63e56c13449063a3882ed83b373a2 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-08-19T23:34:37Z (GMT) No. of bitstreams: 1 LeandroViniciusFernandesDeMorais_DISSERT.pdf: 1776137 bytes, checksum: 5be63e56c13449063a3882ed83b373a2 (MD5) / Made available in DSpace on 2016-08-19T23:34:37Z (GMT). No. of bitstreams: 1 LeandroViniciusFernandesDeMorais_DISSERT.pdf: 1776137 bytes, checksum: 5be63e56c13449063a3882ed83b373a2 (MD5) Previous issue date: 2015-03-30 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Licania rigida Benth e a Turnera ulmifolia Linn. var. elegans s?o esp?cies de plantas regionais do semi?rido empregadas no tratamento de diversas doen?as. Objetivos: O intuito desse trabalho foi caracterizar quimicamente os extratos e fra??es e investigar o potencial antimicrobiano e antioxidante. Metodologia: Para a an?lise qu?mica foram realizadas a quantifica??o total de compostos fen?licos por espectrofotometria e a caracteriza??o cromatogr?fica dos extratos e fra??es. A avalia??o da atividade antioxidante foi realizada pela determina??o da capacidade de sequestro do radical DPPH?. A atividade antimicrobiana foi avaliada pelos ensaios de difus?o em ?gar, microdilui??o em caldo e cin?tica de morte. Resultados: Os extratos e fra??es de L. rigida e T. ulmifolia apresentaram elevado conte?do fen?lico, com a presen?a de flavonoides, dos quais foram determinados como marcadores qu?micos. Observou-se que os extratos de ambas as esp?cies agiram como agentes sequestradores no ensaio da atividade antioxidante in vitro. O extrato da L. rigida foi a ?nica ativa contra cepas de S. aureus, S. aureus meticilina resistente, S. epidermidis, e as leveduras, Candida albicans, Candida dubliniensis, Candida tropicalis, Candida parapsilosis, Candida rugosa, Candida krusei eTrichosporon asahii. Conclus?o: Com base nesses resultados ? poss?vel afirmar que atividade antioxidante e antimicrobiana possivelmente ? atribu?da a presen?a de polifen?licos e flavonoides evidenciados nos extratos e fra??es. / Introduction: Licania rigida Benth and Turnera ulmifolia Linn. var. elegans are species of semi-arid regional plants used in the treatment of various diseases. Objectives: The purpose of this study was chemically characterize the extracts and fractions and investigate the antimicrobial and antioxidant potential. Methods: For chemical analysis, were performed spectrophotometric quantification of the total phenolic and characterization of the extracts by chromatographic analysis. Evaluation of antioxidant activity was done by determining the radical scavenging capacity DPPH ?. Antimicrobial activity was evaluated by agar diffusion, broth microdilutionand time-kill assays. Results: The extracts and fractions L. rigid and T. ulmifolia showed a high phenolic content, the presence of flavonoids, which were determined as chemical markers. It was observed that the extracts of both species performed as sequestering agents in the trial of antioxidant activity in vitro. The L. rigida extract was the only active front strains of S. aureus 33591 (methicillin-resistant), S. aureus 29213, S. epidermidis 12228, and also against the yeast, Candida albicans, Candida dubliniensis, Candida tropicalis, Candida parapsilosis, Candida rugosa, Candida krusei eTrichosporon asahii. Conclusions: Based on these results it is possibly affirm the antioxidant and antimicrobial activity of L. rigida and attributed the presence of polyphenolic flavonoid like responsible.
25

Padronização do teste de tetrazólio para avaliação da viabilidade de sementes de três espécies florestais /

Fogaça, Cristiane Alves. January 2003 (has links)
Resumo: Este trabalho teve como objetivos padronizar a metodologia do teste de tetrazólio e avaliar a aplicabilidade deste para a determinação da viabilidade de sementes de Astronium graveolens, Jacaranda cuspidifolia e Parapiptadenia rigida. Inicialmente, procedeu-se à descrição morfológica de sementes e plântulas das espécies em estudo. Para a padronização do teste de tetrazólio foram avaliados diferentes condições de preparo e coloração das sementes, analisando os aspectos dos tecidos, bem como a intensidade e uniformidade de coloração. A partir dessa análise, foram elaborados diagramas de classes de viabilidade para cada espécie. A eficiência das várias condições empregadas para o teste de tetrazólio foi avaliada comparando os resultados destas com os do teste de germinação. Com relação ao teste de tetrazólio concluiu-se que diferentes condições foram eficientes na obtenção de coloração satisfatória, permitindo a diferenciação dos tecidos, mostrando-se adequadas para avaliação da viabilidade de sementes das espécies estudadas, quando comparadas com o teste de germinação. Fica a critério do analista, a escolha das condições de preparo e de coloração, conforme a praticidade operacional, economicidade do processo e urgência dos resultados. / Abstract: This work had objective to verify the aplicability of tetrazolium test in the evaluation of viability of Astronium graveolens, Jacaranda cuspidifolia and Parapiptadenia rigida seeds. Initialy, were realized morphological study of seeds and seedlings of these species. For the standardization of tetrazolium test were evaluated different conditions of prepare and coloration of the seeds, analyzing the aspects of the tissues and the intensity and uniformity of coloration. Were elaborated viability class diagrams for each specie. The efficiency of tetrazolium test were evaluated comparing the results of that with of the germination test. Concluded that different conditions of tetrazolium test were efficient in the obtaintion of satisfactory coloration, permitting to differentiation of the tissues, showing been adapted for evaluation of viability of Astronium graveolens, Jacaranda cuspidifolia and Parapiptadenia rigida seeds, when compared with the germination test. The choice from the prepare and of the coloration conditions, stayed to criterion of the analyst of seeds, in fuction of the facility operational and urgency of the results. / Orientador: Rinaldo César de Paula / Coorientadora: Teresinha de Jesus Deléo Rodrigues / Banca: Ivor Bergemann de Aguiar / Banca: Maria Cristina de Figueiredo e Albuquerque / Mestre
26

Padronização do teste de tetrazólio para avaliação da viabilidade de sementes de três espécies florestais

Fogaça, Cristiane Alves [UNESP] 13 February 2003 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:28:28Z (GMT). No. of bitstreams: 0 Previous issue date: 2003-02-13Bitstream added on 2014-06-13T18:57:41Z : No. of bitstreams: 1 fogaca_ca_me_jabo.pdf: 777526 bytes, checksum: 28864861958f22814141f733a5229a08 (MD5) / Este trabalho teve como objetivos padronizar a metodologia do teste de tetrazólio e avaliar a aplicabilidade deste para a determinação da viabilidade de sementes de Astronium graveolens, Jacaranda cuspidifolia e Parapiptadenia rigida. Inicialmente, procedeu-se à descrição morfológica de sementes e plântulas das espécies em estudo. Para a padronização do teste de tetrazólio foram avaliados diferentes condições de preparo e coloração das sementes, analisando os aspectos dos tecidos, bem como a intensidade e uniformidade de coloração. A partir dessa análise, foram elaborados diagramas de classes de viabilidade para cada espécie. A eficiência das várias condições empregadas para o teste de tetrazólio foi avaliada comparando os resultados destas com os do teste de germinação. Com relação ao teste de tetrazólio concluiu-se que diferentes condições foram eficientes na obtenção de coloração satisfatória, permitindo a diferenciação dos tecidos, mostrando-se adequadas para avaliação da viabilidade de sementes das espécies estudadas, quando comparadas com o teste de germinação. Fica a critério do analista, a escolha das condições de preparo e de coloração, conforme a praticidade operacional, economicidade do processo e urgência dos resultados. / This work had objective to verify the aplicability of tetrazolium test in the evaluation of viability of Astronium graveolens, Jacaranda cuspidifolia and Parapiptadenia rigida seeds. Initialy, were realized morphological study of seeds and seedlings of these species. For the standardization of tetrazolium test were evaluated different conditions of prepare and coloration of the seeds, analyzing the aspects of the tissues and the intensity and uniformity of coloration. Were elaborated viability class diagrams for each specie. The efficiency of tetrazolium test were evaluated comparing the results of that with of the germination test. Concluded that different conditions of tetrazolium test were efficient in the obtaintion of satisfactory coloration, permitting to differentiation of the tissues, showing been adapted for evaluation of viability of Astronium graveolens, Jacaranda cuspidifolia and Parapiptadenia rigida seeds, when compared with the germination test. The choice from the prepare and of the coloration conditions, stayed to criterion of the analyst of seeds, in fuction of the facility operational and urgency of the results.
27

[pt] CULTURA, RISCO, PACIÊNCIA E SUAS RELAÇÕES COM INDICADORES ECONÔMICOS, DEMOGRÁFICOS E DE SAÚDE / [en] CULTURE, RISK, PATIENCE AND ITS RELATIONSHIPS WITH ECONOMIC, DEMOGRAPHIC AND HEALTH INDICATORS

CYNTIA LOPES DE OLIVEIRA 21 May 2021 (has links)
[pt] O campo de pesquisa que busca entender a relação entre cultura e as preferências ao risco e tempo tem se desenvolvido nos últimos dez anos. No entanto, o número de trabalhos que utilizam uma amostra significativa de países, tornando possível a comparação através das nações, ainda é pequeno. Ademais, os trabalhos existentes utilizam o mesmo construto de cultura, o de Hofstede (2001). Sendo assim, este estudo teve o objetivo de identificar, através de uma análise cross-country de 24 nações, se o construto de cultura de Gelfand et al (2001) se relaciona com as preferências ao risco e tempo. Além disso, foram investigadas as relações entre cultura, risco e paciência com indicadores econômicos, demográficos e de saúde. Para atingir a finalidade proposta foram utilizados os dados sobre risco e paciência de Falk et al (2018), o construto de culturas rígidas e tolerantes proposto por Gelfand et al (2011) e indicadores coletados nos sites do World Bank e Transparency International. Após a análise dos resultados não foi encontrada relação entre o construto de cultura de Gelfand com os índices de risco e paciência. No entanto, foram detectadas associações entre o tipo de cultura, rígida ou tolerante, com taxa de mortalidade geral, taxa de mortalidade infantil e índice de gravidez na adolescência. Ao examinar a paciência observa-se que este índice se associa com o PIB per capita, conforme os resultados de Falk et al (2018) e Wang et al (2016), e com a taxa de mortalidade geral. / [en] The field of research that seeks to understand the relationship between culture and preferences for risk and time has developed over the past ten years. However, the number of studies using a significant sample of countries, making it possible to compare across nations, is still small. Furthermore, the existing works use the same culture construct, that of Hofstede (2001). Thus, this study aimed to identify, through a cross-country analysis of 24 nations, whether the culture construct of Gelfand et al (2001) is related to risk and time preferences. In addition, the relationship between culture, risk and patience with economic, demographic and health indicators were investigated. In order to achieve the goal, the data on risk and patience from Falk et al (2018), the construct of tight and loose cultures proposed by Gelfand et al (2011) and indicators collected on the World Bank and Transparency International websites were used. After analyzing the results no relationship was found between the Gelfand culture construct and patience or risk taking. However, associations were detected between the type of culture, tight or loose, with general mortality rate, infant mortality rate and teenage pregnancy rate. When examining patience, it is observed that this index is associated with GDP per capita, according to the results of Falk et al (2018) and Wang et al (2016), and with the overall mortality rate.
28

[en] SEMI-RIGID CONNECTIONS FOR BUILDING SYSTEMS / [es] SISTEMAS CONSTRUCTIVOS SEMI-RÍGIDOS MIXTOS PARA EDIFICACIONES / [pt] SISTEMAS CONSTRUTIVOS SEMI-RÍGIDOS MISTOS PARA EDIFICAÇÕES

LEON TOLSTOI SALLES FERREIRA 09 October 2001 (has links)
[pt] Este trabalho teve como objetivo propor um sistema construtivo misto eficiente e econômico para edificações. Foram concebidos dois detalhes de ligação semi-rígida mista, o primeiro para colunas de extremidade, e o segundo para colunas intermediárias, executados no eixo de maior inércia da coluna. A ligação de extremidade motivou o desenvolvimento de um novo elemento de ligação: o conector T-rib. Sua principal função é transmitir a resultante das barras de armadura de flexão nas regiões de momento negativo para a mesa das colunas de extremidade. O presente trabalho também envolveu uma investigação de dois modelos para ligações semi-rígidas: o modelo analítico simplificado de Kishi-Chen, [CHEN93], e o modelo mecânico do Anexo J do EUROCODE3, [EURO98], gerando duas alternativas para modelos semi-rígidos mistos. O primeiro modelo de cálculo, desenvolvido a partir do modelo de Kishi e Chen, [CHEN93], permite o cálculo dos dois detalhes de ligação citados anteriormente. O segundo modelo proposto foi concebido a partir da incorporação das contribuições do conector T-rib, das cantoneiras de alma e das barras de armadura existentes nos dois detalhes de ligação citados anteriormente, já que o modelo original do EUROCODE3, não considera estas componentes. Uma calibração dos modelos propostos foi executada a partir de uma comparação com valores obtidos experimentalmente no presente trabalho. Uma solução alternativa para conectores de cisalhamento de vigas mistas de concreto e aço também foi desenvolvida. Esta solução consistiu na adaptação do conector de cisalhamento perfobond rib utilizado em pontes mistas para uso em edificações correntes. Esta investigação resultou na criação de um novo layout para este tipo de ensaio. Este novo ensaio permitiu a determinar a contribuição dos cilindros de concreto e barras de armadura nos furos do conector perfobond rib e aferiu, pela primeira vez na literatura, a fórmula de resistência ao cisalhamento para este conector proposta por Oguejiofor e Hosain, [OGUE94]. Para caracterizar os possíveis estados de ruína do conector T-rib uma série de seis ensaios foi executada. Esta etapa de trabalho compreendeu o desenvolvimento de um novo tipo de ensaio de arrancamento projetado especialmente para esta investigação. Para avaliar o desempenho global do sistema construtivo proposto foi construído e ensaiado um pórtico plano semi-rígido misto em escala real, executado de modo a permitir a aferição do comportamento real das ligações, do comportamento do conjunto das viga-mistas e das vigas- colunas da estrutura. Este ensaio permitiu a determinação de curva carga versus. Rotação, uma estimativa dos esforços máximos de flexão nas ligações, etc. / [en] This work focused on the development of an efficient and economic composite building system. This was accomplished by the conception of two new composite major axis connection details for external and intermediate columns. The external column connection detail motivated the creation of a new connection element: the T-rib connector. The main purpose of this element is to transmit the reinforcement bars forces directly to the external columns in negative moment regions The present study also comprehended an nvestigation of two semi-rigid connections design models:the simplified analytical model of Kishi-Chen, [CHEN93], and the Eurocode 3 mechanical model,[EURO98], leading to further developments in both structural models. The first proposal extends the Kishi-Chen model, [CHEN93], for the external and intermediate columns connections investigated in this work. The second proposal incorporated the contributions of the T-rib connector, the web angles and the reinforcement bars on the EUROCODE3 model, since they were not originally taken into account. Both model were calibrated against the experimental results produced in the present investigation. An alternative solution for composite beams shear connectors was also developed. This solution consisted of an adaptation of the perfobond rib shear connector, generally used in composite bridges, to residential or commercial building construction. This investigation resulted in the development of a new test layout for the required experiments. These experiments enabled the determination of the individual contribution of the concrete dowels and reinforcement bars used in the perfobond rib connector holes. As far as it is known, these tests enable the calibration and evaluation V of each individual term of the perfobond rib resistance formula proposed by Oguejiofor and Hosain, [OGUE94]. A set of six tests was also made to characterise the T-Rib connector ultimate limit states. This procedure also required the development of a new pullout test procedure and layout especially designed for this purpose. To evaluate the global performance of the proposed building system a full-scale composite semi-rigid portal frame was built and tested up to collapse. The experimental programme provided information on real structural behaviour where the influence of connections, beam as beam column behaviour ads second order efectswere full investigated. This experimental research enabled the determination of: load versus rotation curves, an estimation of the maximum connection s bending forces, etc. / [es] Este trabajo tiene como objetivo proponer un sistema constructivo mixto eficiente y económico para edificaciones. Fueron concebidos dos detalles de llamada semi-rígida-mixta, el primero para columnas de extremidad, y el segundo para columnas intermediárias, ejecutados en el eje de mayor inercia de la columna. La llamada de extremidad motivó el desarrollo de un nuevo elemento de llamada: el conector T rib. Su principal función es transmitir la resultante de las barras de armadura de flexión en las regiones de momento negativo para la mesa de las columnas de extremidad. Este trabajo también investiga dos modelos para conexiones semi rígidas: el modelo analítico simplificado de Kishi Chen, [CHEN93], y el modelo mecánico del Anexo J del EUROCODE3, [EURO98], generando dos alternativas para modelos semi rígidos mixtos. El primer modelo de cálculo, desarrollado la partir del modelo de Kishi y Chen, [CHEN93], permite el cálculo de los dos detalles de llamada citados anteriormente. El segundo modelo propuesto fue concebido a partir de la incorporación de las contribuciones del conector T rib, de las esquineras de alma y de las barras de armadura existentes en los dos detalles de llamada citados anteriormente, ya que el modelo original del EUROCODE3, no considera estas componentes. Los modelos propuestos fueron calibrados a partir de una comparación con valores obtenidos experimentalmente en el presente trabajo. Una solución alternativa para conectores de cisallamento de vigas mixtas de concreto y acero también fue desarrollada. Esta solución consistió en la adaptación del conector de cisallamento perfobond rib utilizado en puentes mixtas para uso en edificaciones corrientes. Esta investigación tuvo como resultado la creación de un nuevo layout para este tipo de ensayo. Este nuevo ensayo permitio determinar la contribución de los cilindros de concreto y barras de armadura en las perforaciones del conector perfobond rib y ajustó, por primera vez en la literatura, la fórmula de resistencia al cisallamento para este conector propuesta por Oguejiofor y Hosain, [OGUE94]. Para caracterizar los posibles estados de ruina del conector T rib, se ejecutó una série de seis ensayos. Esta etapa del trabajo comprendió el desarrollo de un nuevo tipo de ensayo de arranque proyectado especialmente para esta investigación. Para evaluar el desempeño global del sistema constructivo propuesto, fue construido un pórtico plano semirígido mixto en escala real, ejecutado de tal modo que permita el ajuste del comportamiento real de las conexiones, del comportamiento del conjunto de las viga mixtas y de las vigas columnas de la extructura. Este ensayo permitió la determinación de curva carga versus Rotación, una estimativa de los esfuerzos máximos de flexión en las conexiones, etc.
29

WARM STRATIFICATION INCREASES GERMINATION OF DENDROMECON RIGIDA AND EHRENDORFERIA CHRYSANTHA

Garcia, Cesar 01 June 2019 (has links)
We explored the seasonal factors that might play a role in triggering germination of Dendromecon rigidaand Ehrendorferia chrysantha.D. rigida and E. chrysantha have been found difficult to germinate using common greenhouse techniques, Keeley and Fotheringham successfully germinated both species after storing their seeds in the field over a year and treating them with smoke. Identifying the specific seasonally changing factors that stimulated germination could have implications for understanding germination requirements for these and other hard-to-germinate chaparral species. Dendromecon rigidaand Ehrendorferia chrysanthaare part of the Papaveraceae family and both are found in the chaparral environment in Southern California. Both species are known to increase in numbers after fire events. Both are believed to have morphophysiological dormancy based on their miniscule embryo and increase in seedling presence after fire events. Climate within the chaparral environment consists of hot, dry summers and cold, wet winters. Storing seeds of D. rigidaand E. chrysantha in the field over winter and spring months resulted in increasing germination for D. rigida seeds that were imbibed in smoke-water. Germination of D. rigidaseeds occurred within six weeks and no further germination was noted beyond that. Ehrendorferia chrysanthaseeds failed to germinate in the field. Lab studies tested effects of stratification at different temperatures (5ºC, 10ºC, 18ºC, 25ºC and 30ºC), stratification for different durations (0, 2, 4, 8, and 12 weeks), heat-shock, and fluctuating moisture and temperature conditions on a weekly time scale, on germination of both species. Of all these treatments the only combination that was effective in germinating seeds of D. rigidaand E. chrysanthawas warm stratification at 30ºC for 8 weeks following smoke-water imbibition. Under these conditions seeds of D. rigidaand E. chrysanthagerminated to 10% and 9.3%, respectively. Further studies on D. rigidaindicated a stratification temperature optimum between 30-40ºC with germination increasing with lack of light. These tested conditions corresponded to the daily peak soil temperatures measured at shallow depth in an area of chaparral inhabited by D. rigida. The period immediately after the first rain event after a fire may provide the chemical cues and warm stratification required to germinate buried seeds in this species.
30

Biodiversity along a gradient of modification : plant invertebrates and reptile diversity in mid-altitude tall tussock (Chionochloa rigida) grasslands, eastern Central Otago, New Zealand

Dixon, Katherine Marguerite, n/a January 2005 (has links)
This thesis set out to examine the soils, plants, lichens, invertebrates and common skinks along a gradient of habitat modification. This gradient was represented by ten study sites, of varying management histories, in a mid altitude tall tussock (Chionochloa spp.) grassland in eastern Central Otago. One extreme of the gradient was represented by intact tall tussock plants with a high density of inter tussock vegetation. The other extreme was represented by intensively managed exotic pasture. Native plants, invertebrates and reptiles were present along the entire gradient of modification and there was a clear threshold in the diversity of native plants along the gradient. This threshold was reached after the management practice of ploughing was applied to a site. Sites that had not been ploughed were found to be similar in their native plant diversity, and all unploughed sites had significantly higher native plant diversity than unploughed sites. There was considerable variation in the abundance of individual plant and Coleoptera species along the modification gradient. The most intensively modified sites had the lowest plant diversity, the lowest abundance and diversity of Orthoptera, as well as the lowest abundance of common skinks. Sites with low levels of modification contained a higher abundance of common skinks, and, native forbs, lichens and bryophytes than the more intensively modified sites. With regard to individual plant and Coleoptera species recorded, there were generally not clear thresholds for their presence and absence along the modification gradient. Rather, there was a gradual turnover for most species along the gradient such that the plant and Coleoptera community at opposing ends of the gradient had less species in common sites of similar modification levels. A high proportion of the Coleoptera species observed were present in all sites, suggesting that disturbance has selected for an adaptive generalist life trait, and that the species remaining comprise the resilient portion of the Coleoptera fauna. The relationship between Coleoptera communities and the gradient of modification was scale dependent, with the strongest relationship being observed at the largest scale measured. The hypothesis that faunal diversity and abundance would be best predicted by the structural diversity of the vegetation rather than by plant species diversity was tested. Structural diversity was strongly correlated (p < 0.01) with Coleoptera diversity, and Coleoptera abundance whereas plant species diversity was not. However, plant species diversity was a stronger correlate of common skink abundance than plant structural diversity. The structural diversity of the vegetation has the potential to be measured remotely and could be a correlate for faunal diversity and abundance when undertaking landscape scale studies. This thesis demonstrates that native biota exists within the agricultural environment of the mid-altitude tall tussock (Chionochloa rigida) grasslands of eastern Central Otago despite intensive modification in some areas. The findings suggest that it is possible to integrate the objectives of agriculture and the conservation of some faunal groups especially for the more resilient species. However, this study also indicates that relatively unmodified sites are valuable reservoirs of biodiversity in the mid altitude zone and it is recommended that the limited number of lightly modified sites that remain in the mid altitude zone be conserved.

Page generated in 0.0462 seconds