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  • 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.
151

Análise de caminhos de transferência de energia no projeto de sistemas de controle / Transfer path analysis in the design of active control system

Melo, Fábio Xavier de 11 April 2013 (has links)
A análise de caminhos de transferência de energia (TPA na sigla em inglês para Transfer Path Analysis) corresponde a um grupo de métodos numérico/experimental para análise e solução de problemas vibro-acústicos de sistemas lineares invariantes no tempo, sendo seu principal campo de aplicação a indústria automotiva. A TPA é uma técnica que identifica as principais fontes de vibração e ruído, e os caminhos estruturais e acústicos pelos quais são transmitidas para determinados locais de interesse. Conhecendo as fontes de ruído e vibração e os caminhos de propagação é possível propor modificações eficientes em minimizar o ruído/vibração nas regiões de interesse, ou atribuir características desejáveis para tais componentes, envolvendo técnicas de controle passivo e ativo. Este trabalho apresenta um estudo numérico e experimental das técnicas de TPA, utilizando métodos diretos e inversos de determinação de forças operacionais. Estes estudos foram realizados em um mockup de um veículo, com o objetivo de determinar o caminho de maior contribuição para o ruído no interior do protótipo, e a partir deste resultado, propor um sistema de controle ativo para minimizar este ruído interno. / The Transfer Path Analysis (TPA) is a group of numerical/experimental tools for the analysis and troubleshooting of noise and vibration problems in linear time invariant vibroacoustic systems, being the automotive sector its major user. TPA consists of a numerical/experimental analysis that allows the identification of the main noise and vibration sources and the structural/acoustic transfer paths to the Target points. Based on the sources and paths, it is possible to propose modifications that efficiently minimize noise and vibration at the target positions. By means of active control it is possible to modify noise and vibration in order to change, rather than minimize noise and vibration, achieving certain design targets. This work presents a numerical and experimental study of TPA techniques, using direct and inverse operational loads determination methods. These studies were performed on a vehicle mockup, in order to determine the path of greatest contribution to the noise inside the prototype, and from this result, propose an active control system to minimize this internal noise.
152

Dialelo completo e associação entre caracteres de rendimento em trigo (Triticum aestivum L.) / Full diallel and association among yield traits in wheat (Triticum aestivum L.)

Pelegrin, Alan Junior de 03 August 2017 (has links)
Submitted by Gabriela Lopes (gmachadolopesufpel@gmail.com) on 2017-08-23T13:47:55Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertação TopCD.pdf: 1350439 bytes, checksum: 0566d9ec824051dc45f1ae413a77db95 (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2017-09-01T19:22:13Z (GMT) No. of bitstreams: 2 Dissertação TopCD.pdf: 1350439 bytes, checksum: 0566d9ec824051dc45f1ae413a77db95 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-09-01T19:22:13Z (GMT). No. of bitstreams: 2 Dissertação TopCD.pdf: 1350439 bytes, checksum: 0566d9ec824051dc45f1ae413a77db95 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-08-03 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / O objetivo deste trabalho foi avaliar a capacidade combinatória em um dialelo completo de trigo na geração F2, como critério para seleção de genitores promissores, bem como, revelar as associações de causa e efeito entre os componentes e o rendimento de grãos em função de diferentes manejos de nitrogênio. Foram realizados dois experimentos no campo experimental da Universidade Federal de Santa Maria Campus Frederico Westphalen. No primeiro experimento foram utilizados cinco genótipos de trigo (Tbio Mestre, Mirante, Quartzo, Pampeano e Fundacep Horizonte), submetidos a cruzamentos artificiais no ano de 2013, conforme modelo dialélico completo. Em 2015, as 20 populações F2’s e os cinco genitores foram conduzidos em blocos aumentados de Federer, e os genitores dispostos em quatro repetições. Os caracteres avaliados foram: massa de grãos por planta, altura de inserção da espiga, estatura de planta, número de afilhos férteis, espaçamento entre espigueta na espiga, número de espiguetas e comprimento da espiga. Foram realizadas as análises de capacidade geral e específica de combinação, efeito recíproco materno e não-materno. O segundo experimento foi conduzido em blocos ao acaso, sob esquema de parcelas subdivididas, com três genótipos (Fundacep 52, TBIO Mestre e TBIO Itaipu), duas fontes nitrogenadas (Ureia e Nitrato de amônia) e quatro manejos de nitrogênio (I: ausência de nitrogênio, II: 100% no afilhamento, III: 50% no afilhamento e 50% no emborrachamento e VI: 33,3% no afilhamento, 33,3% no emborrachamento e 33,3% no florescimento). Os caracteres avaliados foram: massa de mil grãos, número de grãos por espiga, massa de grãos na espiga principal, rendimento de grãos, estatura de planta, número de afilhos férteis e comprimento da espiga. Foram realizadas a análise de variância conjunta e posteriormente a correlação linear de Pearson e análise de trilha individual para cada manejo de nitrogênio. O genitor Cep Horizonte apresenta elevada capacidade de combinação para massa de grãos por planta. Quartzo e Mirante maximizaram o número de espiguetas por espiga e comprimento de espiga, respectivamente, e Tbio Mestre mostrou-se promissor para redução da altura de inserção da espiga, estatura de planta e espaçamento entre espiguetas na espiga. Para os cruzamentos realizados existem combinações híbridas favoráveis para pelo menos, uma das características avaliadas com base da capacidade específica de combinação. O efeito recíproco demostra-se presente nos caracteres avaliados. O manejo nitrogenado altera as relações de causa e efeito entre os componentes de rendimento de grãos nos genótipos estudados. A adoção do manejo sem nitrogênio aplicado em cobertura (manejo I), indica a relação de causa e efeito entre o número de afilhos férteis e o rendimento de grãos do trigo. A adoção de qualquer um dos outros manejos de nitrogênio, revela que a massa de grãos da espiga principal e o número de afilhos férteis possui relação de causa e efeito com o rendimento de grãos do trigo. / The aim of this work was to evaluate the combining ability of a wheat F2 generation through a full diallel, as a criterion for selecting promising genitors, as well as to reveal the associations of cause and effect between components and grain yield as function of different nitrogen management. Two experiments were carried out in the experimental field of the Federal University of Santa Maria, Campus Frederico Westphalen. Five wheat genotypes (Tbio Mestre, Mirante, Quartzo, Pampeano e Fundacep Horizonte) were used in the first experiment, which were subjected to artificial crosses in the year of 2013, according to the full diallel model. In 2015, the twenty F2 populations and the five genitors were conducted in Federer´s augmented blocks, with genitors arranged in four repetitions. The evaluated traits were: mass of grains per plant, spike insertion height, plant height, number of fertile tillers, spikelets spacing in the spike, number of spikelets and spike length. There were performed the analyses of general and specific combining ability, maternal and non-maternal reciprocal effects. The second experiment was conducted in randomized blocks, under subdivided plots, with three genotypes (Fundacep 52, TBIO Mestre and TBIO Itaipu), two nitrogen sources (urea and ammonium nitrate) and four nitrogen managements (I: absence of nitrogen, II: 100% at tilling stage, III: 50% at tilling stage, and 50% at booting stage, VI: 33.3% at tilling, 33.3% at booting and 33.3% at flowering. The evaluated traits were: mass of a thousand grains, number of grains per spike, mass of grains in the main spike, grain yield, plant height, number of fertile tillers and spike length. It was performed the analysis of joint variance followed by Pearson´s linear correlation and individual path analysis for each nitrogen management. The genitor Cep Horizonte presents high combining ability for mass of grains per plant. Quartzo and Mirante maximized the number of spikelets per spike and spike length, respectively, and Tbio Mestre presented itself promising for reduction of spike insertion height, plant height and spikelet spacing in the spike. Regarding the crosses performed, there are favorable hybrid combinations for at least one of the evaluated traits based on the specific combining ability. The reciprocal effect is present in the evaluated traits. Nitrogen management alters the relation of cause and effect among grain yield and its components. The adoption of no nitrogen on topdressing (management I) indicates the cause and effect relationship between number of fertile tillers and grain yield of wheat. The adoption of any other nitrogen managements reveals that mass of grains in the main spike and number of fertile tillers present cause and effect relationship with grain yield.
153

Efeitos diretos e indiretos de características de plantas sobre a similaridade na composição de insetos herbívoros e parasitoides associados à Asteraceae / Direct and indirect effects of plant characteristics on the herbivores and parasitoids compositional similarities associated with Asteraceae

Alvarenga, Vinícius Silva de 15 March 2018 (has links)
Submitted by Franciele Moreira (francielemoreyra@gmail.com) on 2018-04-12T12:45:11Z No. of bitstreams: 2 Dissertação - Vinícius Silva de Alvarenga - 2018.pdf: 1904835 bytes, checksum: bbe0e840d010a67f148c91a849dbbf10 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2018-04-13T11:08:09Z (GMT) No. of bitstreams: 2 Dissertação - Vinícius Silva de Alvarenga - 2018.pdf: 1904835 bytes, checksum: bbe0e840d010a67f148c91a849dbbf10 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-04-13T11:08:09Z (GMT). No. of bitstreams: 2 Dissertação - Vinícius Silva de Alvarenga - 2018.pdf: 1904835 bytes, checksum: bbe0e840d010a67f148c91a849dbbf10 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-03-15 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Understanding how interactions between trophic levels structure species composition is one of the main goals of ecological studies. Mechanisms that explain the compositional structure of parasitoid insects usually neglect the direct and indirect effects of plants’ characteristics, which can also determine the compositional structure of their host herbivore insects. In this context, our goal was to evaluate how plants’ characteristics (abundance, floral phenology, and phylogenetic distance) and herbivores’ compositional similarity determine parasitoids’ compositional similarity. As study system, we used Asteraceae species, flower-head feeding insects, and parasitoids. Using path analysis, we considered parasitoids and herbivores’ similarities, in qualitative (Sørensen similarity), quantitative (Bray-Curtis similarity), and phylogenetic proximity (taxonomic Sørensen similarity) terms. In general, we demonstrated that herbivores’ similarity is the major predictor of parasitoids’ similarity. Even though the effects of plants’ characteristics explained the smallest part of the variation in parasitoids’ similarity, these characteristics had inconsistent relative importance among the similarity indexes used here. Thus, our results indicate that although plant species constitute a potential additional barrier for the parasitoids of endophagous herbivores to find their insect hosts, herbivore parasitoids in flower heads of Asteraceae do not see the plant species in this way. The parasitoids respond mainly to the compositional variation of their insect hosts in the plant species that the latter consume. Therefore, we show how the composition of the upper trophic levels in this tri-trophic system is structured directly and indirectly by antagonistic interactions. / Entender quais fatores influenciam a variação na composição de espécies em sistemas multitróficos é um objetivo fundamental em ecologia. Entretanto, estudos sobre a composição local de insetos parasitoides geralmente negligenciam a importância relativa das características de plantas consumidas por seus insetos herbívoros hospedeiros. Neste contexto, nosso objetivo foi avaliar os efeitos diretos e indiretos, mediados pela similaridade de herbívoros, da distância filogenética, da sincronia do período de floração e da similaridade de abundância das plantas sobre a similaridade de parasitoides. Como sistema de estudo, usamos espécies de Asteraceae, herbívoros endófagos de capítulos e insetos parasitoides. Usando análises de rotas, consideramos as similaridades de herbívoros e parasitoides entre pares de espécies de plantas em termos qualitativos (similaridade de Sørensen), quantitativos (similaridade de Bray-Curtis) e filogenéticos (similaridade de Sørensen taxonômica). Em geral, demonstramos que a similaridade de herbívoros é o principal determinante da similaridade de parasitoides. Mesmo que as características das plantas tenham explicado a menor parte da variação na similaridade de parasitoides, essas características tiveram importâncias relativas inconsistentes entre os índices de similaridade usados. Dessa forma, nossos resultados indicam que, apesar das espécies de plantas constituírem uma barreira adicional potencial para os parasitoides de herbívoros endófagos encontrarem os seus hospedeiros, os parasitoides de herbívoros em capítulos de Asteraceae não as enxergam dessa forma. Estes parasitoides respondem principalmente à variação composicional dos seus hospedeiros nas plantas que estes últimos consumem. Logo, demonstramos como as composições dos níveis tróficos superiores nesse sistema tri-trófico é estruturado diretamente e indiretamente por interações antagônicas.
154

Relações hídricas, trocas gasosas e atividade enzimática de Urochloa ruziziensis inoculada com Azospirillum brasilense, sob déficit hídrico / Water relations, gas exchange and enzymatic activity of Urochloa ruziziensis inoculated with Azospirillum brasilense, to drought

Bulegon, Lucas Guilherme 19 February 2016 (has links)
Made available in DSpace on 2017-07-10T17:37:13Z (GMT). No. of bitstreams: 1 Lucas Guilherme Bulegon.pdf: 2078794 bytes, checksum: ccb242a3255f730bf9153212913cc026 (MD5) Previous issue date: 2016-02-19 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The water deficit causes the plant physiological and biochemical disarray, so is sought ways to reduce these effects and increase the tolerance of plants to water stress. Thus, the present study aimed to evaluate the physiological behavior and biochemical Urochloa ruziziensis inoculated with Azospirillum brasilense via seed and leaf (foliar spray) in conditions induced and controlled water deficit. We used the randomized block design and the treatments, control, inoculation of A. brasilense in seeds, foliar spay application of A. brasilense, combination of seed inoculation and foliar spay application of A. brasilense, segmented into four steps. I - factorial scheme 2x2x13, presence and absence of inoculated seeds, presence and absence of water deficit, and light levels, evaluating gas exchange in moderate drought, severe and rehydration. II - 2x4 factorial scheme, the presence and absence of drought, and the four treatments by assessing daily relative water content, soil moisture and gas exchange. III - was used treatments in drought and irrigated control, being determined, the soluble protein content and the activity of superoxide dismutase, peroxidase (SOD) and catalase, and the contents of chlorophyll a and b, and carotenoid. IV - was the analysis of correlations, track and major components for the plants kept in water restriction and irrigated maintained. The results showed that the use of A. brasilense via seed, makes the culture reach greater photosynthetic activity, less point compensation in severe stress conditions. For water relations, gas exchange and enzyme activity, A. brasilense, inferred positively, especially foliar application, with pronounced effects on stomatal regulation and enzymatic action. By observing the variables linked to maintenance of photosynthesis stood out stomatal conductance (moderate and severe) and SOD (severe). In rehydrating the A. brasilense acted in stomatal and enzymatic regulation, leading to a recovery in order to not harm the plant. It follows that the use of A. brasilense regardless of the form increases the tolerance to water deficit in U. ruziziensis, however foliar application has pronounced effect in relation to the main variables associated with the maintenance of photosynthesis and greater prospect of use / O déficit hídrico causa na planta um descontrole fisiológico e bioquímico, assim busca-se formas para reduzir esses efeitos e aumentar a tolerância das plantas a restrição hídrica. Desta forma, o presente estudo objetivou, avaliar o comportamento fisiológico e bioquímico de Urochloa ruziziensis inoculada com Azospirillum brasilense via semente e foliar, em condições de déficit hídrico induzido e controlado. Utilizou-se o delineamento em blocos casualizados e os tratamentos, controle, inoculação de A. brasilense nas sementes, aplicação foliar de A. brasilense, combinação entre inoculação das sementes e aplicação foliar de A. brasilense, segmentado em quatro etapas. I - Esquema fatorial 2x2x13, presença e ausência da inoculação nas sementes, presença e ausência de déficit hídrico, e níveis de luminosidade, avaliando as trocas gasosas em déficit hídrico moderado, severo e reidratação. II - Esquema fatorial 2x4, a presença e ausência do déficit hídrico, e os quatro tratamentos, avaliando-se diariamente teor relativo de água, umidade do solo e as trocas gasosas. III- Utilizou-se os tratamentos em déficit hídrico e o controle irrigado, determinando-se, o teor de proteínas solúveis e a atividade das enzimas superóxido dismutase, peroxidase (SOD) e catalase, e os teores de clorofila a e b, e carotenoides. IV - consistiu na análise de correlações, trilha e de componentes principais para as plantas mantidas em restrição hídrica e mantidas irrigadas. Os resultados mostraram que o uso de A. brasilense via semente, faz com que a cultura alcance maior atividade fotossintética, com menor ponto de compensação em condições de déficit severo. Para as relações hídricas, trocas gasosas e atividade enzimática, o A. brasilense, inferiu positivamente, se destacando a aplicação foliar, com efeitos pronunciados na regulação estomática e ação enzimática. Ao observar as variáveis ligadas a manutenção da fotossíntese destacou-se a condutância estomática (moderado e severo) e a SOD (severo). Na reidratação o A. brasilense atuou na regulação estomática e enzimática, levando a uma recuperação de forma a não prejudicar a planta. Conclui-se que o uso de A. brasilense independente da forma eleva a tolerância ao déficit hídrico em U. ruziziensis, contudo a aplicação foliar tem efeito pronunciado em relação as principais variáveis ligadas a manutenção da fotossíntese, além de maior perspectiva de uso
155

民意代表網站瀏覽者行為之實證研究 / An empirical study of visitors' behavior on a political website

楊堯燦, Yang, Yao-Tsan Unknown Date (has links)
全球上網人數不斷增加,沒有電腦、沒有網路的生活對現今的許多人,尤其是資訊相關產業的工作者來說,實在難以想像。就像以前的人應也很難想像現在電腦網路所帶來的便利,這樣巨大的改變已完全形成現代人生活上的改變。許多企業因此不得不E化,即使E化所能帶來的好處尚難以估計,為了不輸在起跑點,投注大筆資金E化的企業並不在少數。 民意代表雖屬非營利組織,但其表現需接受選民定期的檢驗,用投票來反應,不是零就是一百的績效衡量方式,比一般企業所面臨的損益來得殘酷。為了拉近與選民的距離,以網際網路做為媒介是個不錯的選擇。究竟民意代表經營網站能為其帶來多少支持的選民,甚而轉化為支持的選票,值得探討。上民意代表網站的瀏覽者行為特性如何,網站經營者可如何發揮以吸引瀏覽者,增加瀏覽人次? 本研究以Howard的消費者決策模式(CDM)為基礎,配合本研究題目的特定範圍加以修正,利用路徑分析(Path Analysis)探討瀏覽者行為在數個構面上的影響關係,再以單因子變異數分析(1-way ANOVA)界定各構面在年齡、職業及區域上的差異,最後形成策略意涵。 根據研究結果,做成以下建議:以長期來看,民意代表經營專屬網站有助於爭取更多支持的選民;爭取學生族群的認同;台北市南區的候選人,目前適合搭配專屬網站作為整體的競選文宣。 / Nowadays there are more and more people going online. It’s unimaginable how people could live without Internet, especially for those who do their job using computer frequently through Internet. Just as we could not imagine what utilities Internet bring hundreds of years ago. It goes without saying that Internet has changed our lives. That’s why lots of business go online to be an E-business. Though the benefit brought by going on line can’t be clearly estimated, lots of corporate spend much money constructing their E-business because of avoiding lost in the beginning. Political websites are all nonprofit organizations. The way their performances are evaluated is election. It’s cruel that you are a survivor or getting nothing but crash otherwise. The Candidates want to be more closer to ’customers’, so they choose to setup a website and provide service. But How can they be sure that they are more possible to win the final campaign? The answer is in this paper. It is going to find out the behavior of those who visit the websites and make some suggestion about the strategies to promote the websites. The structure of this research is based on the CDM(Consumer Decision-Making) Model with some specific modification. The related dimensions are connected using Path Analysis, then the interactive relationship of these dimensions are clear. Accompanied by 1-way ANOVA, we can find the characteristics of the visitors’ on these dimensions, say age, occupation and where they live. According to the outcome, our suggestions are : it’s helpful for the candidates to win the campaign in the long run by providing services on websites ; ‘Student’ is apparently the group which is worth targeting when you want to promote yourself ; it’s now appropriate to concentrate on website if you are a candidate in the south area of Taipei.
156

The planning of the Castle Peak 'B' power station project /

Lam, Wan-chung, Jimmy. January 1900 (has links)
Thesis (M.B.A.)--University of Hong Kong, 1983.
157

經濟投票之路徑分析:2012年總統選舉之研究 / Economic Voting in Taiwan: A Path Analysis of the 2012 Presidential Election

林政宇, Lin, Cheng Yu Unknown Date (has links)
經濟投票研究逐漸重視內因問題,國外的研究對於資料上和方法上均展開革新。相較之下,台灣的經濟投票研究受限於資料和方法,一直無法對認知性與資料性的內因問題進行有效的處理。資料的侷限不是一時能獲得改善的。但方法的反思和修正,正是研究者與方法對話讓方法實用的開始(黃紀 2000b)。處理經濟投票的二個內因問題,本文引用Menard(2010, 145-168)所提出的PALR方法。它保留路徑分析的優點,並讓類別變數能夠在路徑分析方法中被估計;同時結合Heckman因果效應模型的概念,亦能處理資料性的內因問題。 2012年總統選舉「九二共識」和「台灣共識」的交鋒,最後是由主打透過「九二共識」提振台灣經濟的執政黨獲勝。面對前一個任期表現差強人意的執政黨,選民沒有對它進行處罰,反倒再給它執政的機會。這樣的選舉結果讓人聯想是否還有其他因素影響經濟評估。透過PALR希望能一窺2012年總統選舉的全貌。 研究發現,2012年總統選舉存在社會前瞻經濟投票,卻不存在社會回溯經濟投票。政黨認同對社會回溯型經濟評估有直接影響,對社會前瞻型經濟評估則是有間接影響;而且對投票選擇的影響不只存在直接影響力,透過候選人形象評估和社會前瞻型經濟評估,政黨認同對於投票選擇也有相當的間接影響力。這表示選民不僅是有立場地對執政黨2008年到2012年的表現進行評估;對台灣未來的展望同樣存在政黨認同的影響。選民不僅有立場地評估代表二個「共識」的候選人,也有立場地看待台灣未來可能的發展。
158

Traits de personnalité, événements de vie et troubles psychopathologiques associés à l’idéation suicidaire chez les étudiants de licence / Personality traits, life events and psychopathological disorders related to suicide ideation among undergraduate students

Mahr, Safia 30 January 2015 (has links)
Objectif. L’idéation suicidaire est la première étape dans la spirale infernale du comportement suicidaire. Pour mieux prévenir l’idéation suicidaire, le but de notre étude est d’investiguer ses prédicteurs chez des étudiants de licence : traits de personnalité, stress lié aux événements devie, troubles psychopathologiques, estime de soi, satisfaction de la vie et relations interpersonnelles.Méthode. L’étude s’est déroulée { l’Université Paris Ouest Nanterre la Défense entre 2008 et 2010, et nous avons recueilli les données auprès d’un échantillon de 855 étudiants (âge moyen de 23 ans, écart-type de 5,5 ans; H = 198, F = 657) provenant de plusieurs filières de licence, mais avec une forte surreprésentation de la filière de psychologie (n=614). Nous avons utilisé une batterie d’instruments pour mesurer les variables cibles.Résultats. Les résultats des analyses en pistes causales avec médiation montrent que seulementquelques variables prédictrices expliquent plus de la moitié de la variance de l’idéation suicidaire (52%). Les prédicteurs les plus efficaces en termes de significativité sont l’agréabilité (β entre -0,06 à -0,18), l’estime de soi (β entre -0,08 à -0,52), la présence de l’anxiété-l’insomnie (β entre 0,17 { 0,37), le dysfonctionnement social (β entre 0,09 { 0,23), le trait d’être renfermé (en retrait, introverti) (β entre 0,08 { 0,29), les troubles de pensée (β entre 0,16 { 0,40) et le comportement transgressif (β entre 0,14 { 0,31).Discussion. Malgré les limitations de notre étude, nous constatons qu’un petit nombre de prédicteurs expliquent une variance importante de l’idéation suicidaire et que les prédicteurs ne se comportent pas de façon identique pour les différents sous-groupes ; hommes/femmes, appartenance à la filière psychologie/autres. / Objective. Suicide ideation is the first stage that leads to the vicious circle of suicidal behaviours.Thus, the objective of our research is to investigate the association between suicide ideation andits predictor variables (personality traits, stress related to life events, psychopathological disorders, self esteem, satisfaction with life and interpersonal relationships) amongst undergraduate university students.Method. This study was conducted at the Université Paris Ouest Nanterre la Défence between2008 and 2010. We have collected data from a sample of 855 students (average age of 23 yearsand standard deviation of 5 years and 6 months; M = 198, F = 657) composed of different disciplines but with an overrepresentation of psychology undergraduates (n = 614 with an average age of 23 years; σ = 6). We used a battery of instruments to measure the variables of interest.Results. The results of path analysis show that only a few predictor variables explain more than half of the variance in suicidal ideation (52%). The most effective predictors in terms of significance are: agreeableness (β between -0.06 to -0.18), self-esteem (β between -0.08 to -0.52), comorbidity of anxiety-insomnia (β between 0.17 to 0.37), social dysfunction (β between 0.09 to 0.23), withdrawal (β between 0.08 to 0.29), thought disorders (schizophrenia) (β between 0.16 to 0.40) and rule breaking behaviour (β between 0.14 to 0.31). Discussion. In spite of the limitations of our study, we have found that a relatively small number of predictors explains a significant amount of variance in predicting suicidal ideation. Moreover, predictor variables are not identical for different subgroups.
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An ecological mixed methods study of youth with learning disabilities: exploring personal and familial influences on mental health

Lawrence, Breanna Catherine 27 August 2018 (has links)
There is a notable overlap and co-occurrence of mental health and learning challenges among school-aged youth. Existing research highlights associations between learning disabilities (LD) and mental health problems; however, there has been little exploration of additional variables, such as familial influences, that represent multiple levels of influence (Cen & Aytac, 2016). From a developmental relational systems framework (Overton, 2015), advancing the understanding of familial influences on youth development is crucial. Using a mixed methods design, the present study examined the influences of parent depression, parenting behaviours, family functioning, and youth social and emotional competencies on symptoms of anxiety and depression among youth with LD. Addressing two hypotheses, the quantitative Study 1 aimed to identify factors associated with mediating effects on internalized distress in 14- and 15-year-old youth with LD using secondary analysis of a cross-sectional national sample of youth and their parents. Youth social and emotional competencies and parental monitoring were found to be the most significant buffering influences in reducing symptoms of anxiety and depression. The qualitative Study 2 built on the results from Study 1, to expand the quantitative findings. In Study 2, youth at the end of middle school and their parents were interviewed to gain deeper understanding about the experiences of co-occurring LD and mental health problems from a family perspective. Data analysis identified youth fatigue, youth self-efficacy, and family relationships as central themes related to the challenges youth and their families experienced. Integrating the findings of the two studies illustrated the complex psychological, social, and educational implications for youth with LD in a family context. The interplay of factors embedded in the relation between the LD and mental health problems underscores this complexity, suggesting the relation cannot be completely understood without considering the multiple levels of influences. Implications for theory, research, and practice are described with an emphasis on ecological approaches and building school-family relationships. / Graduate
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Violência entre parceiros íntimos: um fator de risco para a insegurança alimentar domiciliar? / Intimate partner violence: Is it a risk factor for household food insecurity?

Emanuele Souza Marques 25 March 2014 (has links)
Conselho Nacional de Desenvolvimento Científico e Tecnológico / O primeiro objetivo da Tese consistiu na identificação e caracterização dos instrumentos de aferição epidemiológicos que vêm sendo propostos para a abordagem de IA domiciliar, bem como na síntese de suas propriedades psicométricas. Para tal, realizou-se busca sistemática em três bases de dados eletrônicas: MEDLINE, LILACS e SciELO. Não houve delimitação do período de publicação. Os resultados são apresentados no artigo intitulado Household food insecurity: a systematic review of the measuring instruments used in epidemiological studies. Foram identificados 24 instrumentos, todos breves e de fácil aplicação. A maioria foi desenvolvida nos Estados Unidos. O instrumento HFSSM apresentou o maior número de estudos de utilização e psicométricos, podendo ser recomendado sem hesitação. O segundo e principal objetivo desta Tese foi avaliar se a ocorrência de violência psicológica e física entre parceiros íntimos pode ser considerada um fator de risco para a ocorrência de Insegurança Alimentar (IA) domiciliar. As informações que subjazem a pesquisa originaram-se de um inquérito domiciliar realizado no Distrito de Campos Elíseos, Município de Duque de Caxias, entre abril a novembro de 2010. A população de estudo foi selecionada por meio de amostragem por conglomerados em três estágios (setor censitário, domicílio, indivíduo) com técnicas de amostragem inversa para a seleção dos domicílios. A amostra do estudo incluiu 849 mulheres que no período da entrevista relataram possuir algum relacionamento amoroso nos 12 meses anteriores. As informações foram obtidas por meio de entrevista utilizando-se um questionário estruturado, contendo instrumentos previamente validados, como a Revised Conflict Tatics Scales (CTS2) para a mensuração das violências e a Escala Brasileira de Insegurança Alimentar (EBIA) para a IA domiciliar. Utilizou-se a análise de caminhos (Path Analysis) na análise de dados o que permitiu explorar as relações entre as violências, entre estas e o Transtorno Mental Comum (TMC), este último e a IA, bem como as relações mais distais do modelo teórico. Os resultados são apresentados no artigo intitulado Violência entre parceiros íntimos, transtornos mentais comuns e insegurança alimentar: modelagem de equações estruturais. A hipótese central deste estudo foi corroborada, na medida em que tanto a violência psicológica, como a violência física se mostraram importantes fatores de risco para a IA, via a ocorrência de TMC. Contrariamente ao esperado, notou-se um maior efeito da violência psicológica do que da violência física na ocorrência do desfecho. Espera-se que a divulgação dos resultados desta Tese auxilie os profissionais e gestores na área de segurança alimentar e nutricional, bem como pesquisadores da área na tomada de decisões em relação ao instrumento de aferição a ser utilizado para a caracterização das situações e ampliem o olhar sobre o problema, incorporando outros fatores de risco, tais como as violências entre parceiros íntimos, aqueles estritamente econômicos, habitualmente considerados no debate sobre os determinantes e estratégias de enfrentamento da IA. / The first goal of the Thesis that consisted of identifying and characterizing the epidemiological measurement instruments that have been proposed for addressing HFI and synthesis of its psychometric properties. To this end, we performed a systematic search of three electronic databases: MEDLINE, LILACS and SciELO. There was no definition of the publication period. The results are presented in the article entitled "Household food insecurity: a systematic review of the measuring instruments used in epidemiological studies". Twenty-four instruments were identified; all brief and of easy application. The majority were devised in the United States. The HFSSM instrument had the largest number of use studies and psychometric and can be recommended without hesitation. The second and main objective of this Thesis was to evaluate the occurrence of physical intimate partner violence (IPV) of psychological type and can be considered a risk factor for the occurrence of household food insecurity (HFI). The information underlying the research originated from a household survey conducted in the District of Campos Elíseos, in the city of Duque de Caxias, between April and November 2010. The study population was selected using cluster sampling in three stages (census tract, household, individual) with inverse sampling techniques to the selection of households. The study sample included 849 women (82.03% of the interviews for the study background) than during the interview reported having a romantic relationship in the last 12 months. Information was obtained through interviews using a structured questionnaire containing previously validated instruments such as the Revised Conflict Tactics Scales (CTS2) to measure the IPV and Brazilian Food Insecurity Scale (EBIA) for HFI. The results are presented in the article titled "Intimate partner violence, common mental disorders and food insecurity: a survey- based structural equation modeling analysis". The central hypothesis of this study was corroborated, and IPV psychological presented both as direct kick in the occurrence of HFI effect, while the physical type of IPV only had indirect effect via CMD . It is hoped that the dissemination of the results of this thesis assists professionals and managers in the area of food security as well as researchers in the field in making decisions regarding the measurement instrument to be used for the characterization of situations and broaden the look about the problem, incorporating other risk factors such as intimate partner violence, strictly economic ones usually considered in the debate on the determinants and coping strategies of food insecurity.

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