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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.
281

Evaluation of the screening and brief intervention for risky alcohol use in Sibasa Primary Health Care Clinic in Thulamela Municipality

Ramarumo, Mpho 11 February 2015 (has links)
Department of Psychology / PhD (Psychology)
282

Factors associated with risky sexual behaviour amongst students at Venda Technical Vocational Education and Training College in Limpopo Province, South Africa

Murudi, Nthuseni Sharon 05 1900 (has links)
MPH / Department of Public Health / Multiple sexual partners, unprotected sex and transactional sex are considered risky sexual behaviour worldwide and continue to pose risks of sexual transmitted infections, unwanted pregnancy as well as increased termination of pregnancy amongst young people. The reported study was aimed at describing factors associated with risky sexual behaviour amongst students at Vhembe Technical Vocational Education and Training College. Within the quantitative paradigm, the study adopted a descriptive, cross-sectional survey design to describe factors associated with risky sexual behaviour amongst students. The targeted population were all the registered students at Vhembe Technical Vocational Education and Training College, Mashamba Campus. Self-administered questionnaires with close ended questions were administered to 307 students whom were sampled using a simple random technique. Out of 307 students, 217(70.3%) were females and 90 (29.3%) were males. The Statistical Package for Social Sciences version 23.0 was used to manage and analyse data. The study results revealed that demographic factors such as gender, age and sexual orientation contributed to students in engaging in risky sexual behaviour. A majority of the male students 64 (61.2%) were found to be having multiple sexual partners as compared to 107(54.2%) female students. Students aged 21-24 years 98(31.9%) were having multiple sexual partners. The study further revealed that sexual orientation contributes to students engaging in risky sexual behaviour. The students who reported that they were bisexual, gay or lesbian 33 (84.6%) were not using condoms. Environmental factors such as staying alone in a rental place contributed to students engaging in risky sexual behaviour. A majority 97(51.2%) of college students who were staying at a rental place were engaging in unprotected sex. In this study, socio-economic factors such as depending on National Financial Aid Scheme have been identified as the main driver of transactional sex. About 131(49%) students who depend on National Financial Aid Scheme reported were found to be prone to engaging in transactional sex. The study recommends that the Department of Health and Department of Education initiate strategies such as having a clinic inside the Technical Vocational Educational and Training College and peer educators to expand knowledge of students on risky sexual behaviour and on lesbian, gay, bisexual transgender and intersex.
283

Le rôle de l’insula dans la prise de décision risquée : apports de l’évaluation clinique suite à une résection focale unilatérale et de la neuroimagerie fonctionnelle

Von Siebenthal, Zorina 12 1900 (has links)
L'insula a longtemps été considérée essentiellement comme une partie du « cerveau viscéral » du fait de son rôle dans le traitement des réponses physiologiques et viscérales. Or, depuis l’avènement de l’imagerie cérébrale fonctionnelle, son implication dans divers aspects du fonctionnement neuropsychologique est devenue bien établie. De plus en plus d’études suggèrent que le cortex insulaire joue un rôle clé dans les circuits responsables de la prise de décision risquée. L’hypothèse des marqueurs somatiques suggère que les émotions influencent nos décisions aux moyens de changements physiologiques internes et viscéraux. Il a été proposé que l'insula participe à la prise de décision risquée en représentant les états somatiques de la situation chargée émotionnellement et en projetant ces informations au cortex préfrontal ventro-médian, constituant ainsi une structure clé dans les circuits responsables de la prise de décision. Les théories actuelles avancent que l’insula serait davantage impliquée dans la prise de risque lorsque l’individu fait face à une perte potentielle plutôt qu'à un gain. Toutefois, bien que plusieurs études supportent un rôle dans le processus décisionnel, la contribution spécifique du cortex insulaire demeure énigmatique. Les études qui composent cette thèse visent à mieux comprendre la façon dont l'insula participe à la prise de risque aux moyens de tâches neuropsychologiques de gambling qui permettent de simuler des situations de prise de décision de la vie quotidienne. La première étude neurocomportementale examine les conséquences d’une résection au cortex insulaire sur la capacité à prendre des décisions face à un risque potentiel, chez des patients épileptiques réfractaires à la médication qui ont subi une résection unilatérale de cette région. Leurs performances à deux tâches de gambling sont comparées à celles d’un groupe de patients ayant subi une chirurgie de l'épilepsie du lobe temporal (épargnant l’insula) et d’un groupe d’individus contrôles en santé. Les résultats mettent en évidence une altération du patron de prise de risque chez les patients avec résection insulaire, qui se traduit par une difficulté à ajuster leur choix en fonction de la valeur attendue (EV) (c’est-à-dire le ratio entre la magnitude et les probabilités des résultats possibles) de l’option risquée en condition de perte. Cette étude appuie l’idée selon laquelle la prise de décision risquée implique différents processus neuronaux selon si le risque implique un gain ou une perte potentielle. La seconde visée de cette thèse porte sur l’évaluation spécifique de la valence, de l’ampleur, de la probabilité et de l’EV de l’option risquée à l’activité insulaire au cours d’une prise de décision. Au moyen de l’imagerie par résonnance magnétique fonctionnelle, l’activité cérébrale d’individus en santé a été enregistrée, alors qu’ils complétaient une tâche de jeu de hasard. Les résultats de l’étude suggèrent un rôle prédominant de l’insula dans l’ajustement des décisions risquées en fonction de l’EV. De plus, l’activité de l’insula pendant la prise de décision était influencée par la sensibilité à la punition des participants. En somme, les données de cette thèse contribuent à une meilleure compréhension du rôle spécifique de l’insula à la prise de décision risquée et conduisent à une réflexion sur l’évaluation neuropsychologique des atteintes insulaires. / The insula has long been considered primarily as part of the « visceral brain » because of its role in the treatment of physiological and visceral responses. However, since the advent of functional brain imaging, its involvement in various aspects of neuropsychological functioning has become well established. More and more studies suggest that the insular cortex plays a key role in the circuits responsible for risky decision-making. The somatic marker hypothesis suggests that emotions influence our decisions by means of internal and visceral physiological changes. It has been proposed that the insula participates in risky decision-making by representing the somatic states of the emotionally charged situation and projecting this information to the ventromedian prefrontal cortex, thus constituting a key structure in the circuits responsible for decision. Current theories argue that the insula would be more involved in risk taking when the individual faces a potential loss rather than a gain. However, although several studies support a role in the decision-making process, the specific contribution of the insular cortex remains enigmatic. The studies that make up this thesis aim to better understand how the insula participates in risk taking with neuropsychological tasks of gambling that can simulate decision-making situations of everyday life. The first neurobehavioral study examines the consequences of insular cortex resections on the ability to make decisions about potential risk in drug-refractory epileptic patients who have undergone unilateral resection of this region. Their performance in two gambling tasks is compared to a group of patients who had surgery for temporal lobe epilepsy (sparing the insula) and a group of healthy control. The results highlight an alteration of risk taking in patients with insular resection, which results in difficulty in adjusting their choice according to the expected value (EV) (i.e. the ratio between the magnitude and probabilities of possible outcomes) of the risky option in the loss condition. This study supports the idea that risky decision making involves different neural processes depending on whether the risk involves a potential gain or loss. The second aim of this thesis deals with the specific assessment of the valence, magnitude, probability and EV of the risky option to insula activity during a decision-making process. Using functional magnetic resonance imaging, the brain activity of healthy individuals was recorded as they completed a gambling task. The results of the study suggest a predominant role of the insula in adjusting risky decisions based on EV. In addition, the activity of the insular cortex during decision-making was influenced by the participants' sensitivity to punishment. In sum, the data from this thesis contribute to a better understanding of the specific role of the insula in risky decision-making and lead to a reflection on the neuropsychological evaluation of insular lesions.
284

Les relations d'attachement et d'activation parent-enfant et l’anxiété chez les enfants d'âge préscolaire

David, Sophie 10 1900 (has links)
Les troubles anxieux sont les troubles psychologiques les plus prévalents chez les enfants et les adolescents. Les symptômes apparaissent rapidement dans le développement de l’enfant et persistent souvent jusqu’à l’âge adulte. Plusieurs recherches ont été réalisées sur les prédicteurs de l’anxiété. Certaines font ressortir une association entre l’attachement insécurisant et l’anxiété, particulièrement les attachements ambivalent et désorganisé. Depuis quelques années, un nouveau concept est utilisé pour évaluer la relation parent-enfant, la relation d’activation. Cette dernière est complémentaire à la relation d’attachement, car elle considère les dimensions de la discipline et de la stimulation à la prise de risque, alors que l’attachement est basé sur la dimension du réconfort. Plusieurs recherches ont aussi trouvé des associations entre l’anxiété et l’activation. De ce fait, le premier objectif de cette recherche est de déterminer quelle association est plus forte avec l’anxiété entre la relation d’attachement ou la relation d’activation. Le deuxième objectif est de vérifier si le sexe du parent est un modérateur de l’association entre l’anxiété et les deux relations. L'échantillon est composé de 38 parents et de leurs enfants, âgés de 3 à 5 ans. Les instruments de mesure utilisés sont l’échelle d’anxiété/dépression du questionnaire CBCL pour les scores d’anxiété, la situation étrangère pour l’attachement et la situation risquée pour la relation d'activation. Les résultats montrent que la relation d’activation est associée à l’anxiété, alors que ce n’est pas le cas pour la relation d’attachement. De plus, le sexe du parent n’est pas un modérateur des associations entre l’anxiété et les relations. / Anxiety disorders are the most prevalent disorders in children and adolescents. The symptoms appear quickly in the child's development and often persist into adulthood. Many researches have been conducted on the predictors of anxiety. Several studies show that there is an association between insecure attachment and anxiety, particularly ambivalent and disorganized attachment. In recent years, a new concept has been used to evaluate the parent-child relationship, the activation relationship. This new measure is complementary to the attachment relationship because it considers the dimensions of discipline and stimulation to risk taking, while attachment is based on the dimension of comfort. Several studies have also found associations between anxiety and activation. As a result, the primary goal of this research is to determine which association is stronger with anxiety: attachment or activation. The second objective is to understand if the parent's sex is a moderator of the association between anxiety and the two relationships. The sample is composed of 38 parents and their children, aged 3 to 5 years. The measuring instruments used are the anxiety/depression scale of the CBCL questionnaire for the anxiety scores, the strange situation for attachment and for the activation relationship, the risky situation. The results show that the activation relationship is associated with anxiety, whereas this is not the case for the attachment relationship. In addition, the parent's gender is not a moderator of the associations between anxiety and attachment or activation relationships.
285

Uplatnění adiktologa v dětských domovech Ústeckého kraje / Role of addiction specialist in children's home in the Ústí nad Labem region

Králová, Tereza January 2020 (has links)
Background: Studies situated in an institutional care environment point to the fact that addiction issues in institutional care are a topic that deserves special attention, even with regard to the fact that the children of these institutions are considered vulnerable to risky behavior. The Ústí nad Labem Region has long been in the first places in the prevalence of substance use and is also specific in the occurrence of a number of negative social factors. In the whole region there is 1 addiction treatment outpatient clinic focused on the target group of children and adolescents, which during its operation registered repeated demand for specialized help that originates from children's homes. Aim: The main aim of the study is to identify the opportunity of applying an addiction specialist in the children's home in the Ústí nad Labem region. The partial aims of the study are to map the current state of addiction issues in these children's homes and to describe the possible form of cooperation of these facilities and addiction specialist with regard to the identification of barriers to this cooperation. Methods: The research is based on a qualitative approach. The research sample was obtained by a combination of selective sampling method and self-selection method. All 17 children's homes in the Ústí...
286

Consommation de cannabis, impulsivité et comportements routiers à risque chez les jeunes conducteurs

Cordelier, Noémie 04 1900 (has links)
Malgré de nombreux efforts de prévention, les jeunes conducteurs sont surreprésentés dans les accidents routiers. Certaines études ont visé à mettre en évidence les facteurs pouvant influencer les jeunes conducteurs à adopter des comportements risqués. La consommation de cannabis et l’impulsivité ont été identifiées comme des facteurs importants. L’objectif de cette thèse vise à mieux comprendre les liens entre la consommation de cannabis et les comportements routiers risqués, tout en tenant compte de l’impulsivité. Pour ce faire, cette thèse se divise en deux articles. Le premier article vise à vérifier si la fréquence de consommation de cannabis prédit la prise de risque des jeunes conducteurs au-delà de l’effet de leur impulsivité. 209 participants âgés de 17 à 25 ans ont rempli des questionnaires sur leurs comportements routiers, leur impulsivité, et leur fréquence de consommation de cannabis. Les résultats montrent que la fréquence de consommation de cannabis prédit la prise de risque des jeunes conducteurs au-delà de l’effet de l’impulsivité. De plus, l’urgence positive est la seule facette de l’impulsivité qui prédit la prise de risque, indépendamment des habitudes de consommation. Plusieurs hypothèses pouvant expliquer ces résultats ont été proposées dont une qui nous semblait particulièrement pertinente : la probabilité de prendre le volant après avoir consommé est plus élevée dans le cas d’une consommation plus fréquente, ainsi l’effet direct de la substance pourrait expliquer les comportements risqués. C’est pourquoi dans notre deuxième étude, nous avons voulu vérifier si la consommation de cannabis était associée aux comportements risqués même lorsque le consommateur n’est pas sous l’effet du cannabis. Comme une consommation fréquente peut être symptomatique d’un trouble d’utilisation du cannabis (TUC), nous avons voulu vérifier son impact sur les comportements risqués. Le deuxième article compare donc un groupe de consommateurs ayant un TUC avec un groupe n’en ayant pas sur des comportements risqués tout en tenant compte de leur impulsivité. Pour ce faire, 76 participants masculins, consommateurs de cannabis, âgés de 18 à 25 ans, ont complété une tâche de simulation de conduite ainsi qu’une tâche stop-signal, s’étant abstenus de 6 consommer du cannabis dans les 12 heures précédant l’expérimentation. Ils ont aussi rempli des questionnaires sur les habitudes de consommation de cannabis, les traits d’impulsivité et la prise de risque. Les consommateurs ayant un TUC ont manifesté plus de comportements risqués dans le simulateur que ceux n’en ayant pas, quel que soit leur niveau d’impulsivité et sans être sous l’effet de la substance. Plusieurs explications ont été proposées : difficulté d’adaptation à la conduite sans l’effet de la substance; présence d’une autre variable confondante que l’impulsivité sous-jacente à la consommation et aux comportements risqués; effet résiduel de la substance, non détecté par la tâche stop-signal, qui influencerait les comportements routiers. En résumé, il ressort de cette thèse que la consommation de cannabis est un facteur contribuant aux comportements risqués des jeunes conducteurs, et ce indépendamment de l’impulsivité. De plus, les consommateurs ne constituent pas un groupe homogène, d’où la pertinence de cibler particulièrement les consommateurs problématiques dans les campagnes de prévention. / Despite many prevention efforts, young drivers are overrepresented in road crashes. Some studies show that cannabis use and impulsivity are significant predictors of risky driving behaviour among young drivers. The aim of this thesis is to better understand the association between cannabis use and risky driving behaviour, while considering the driver’s impulsivity. For this purpose, this thesis is divided into two articles. The first article aims to verify whether the frequency of cannabis use predicts risk-taking over and above the impulsivity traits of young drivers. 209 participants aged between 17 and 25 completed questionnaires on their driving behaviours, impulsivity, and frequency of cannabis use. Results show that the frequency of cannabis use is a significant predictor of risky driving over and above the five impulsivity traits. Furthermore, positive urgency is the only impulsivity trait which predicts risky driving, regardless of the frequency of cannabis use. Several explanations of these results are proposed, including one we found particularly relevant: the probability of driving under the influence is higher with more frequent use, so the substance effects could explain risky driving behaviour. Therefore, in our second study, we wanted to test whether cannabis use was associated with risky driving behaviour even if the user was not driving under the influence. Moreover, since frequent use can be symptomatic of a cannabis use disorder (CUD), we wanted to verify its impact on risky behaviours. The second article, therefore, compares two groups of cannabis users (with or without CUD) on several driving behaviours, while considering their impulsivity. A sample of 76 male participants, cannabis users, aged 18 to 25, completed a driving simulation task and a stop-signal task, abstaining from cannabis use in the 12 hours preceding the experiment. They also completed questionnaires about their cannabis use patterns, impulsivity traits and risk-taking. Results show that users with a CUD displayed more risky behaviours in the simulator than users without a CUD, regardless of their impulsivity level and without being under the effects of the substance. Several explanations have been proposed: difficulty adjusting to driving without the influence of the substance for users with a CUD; presence of a confounding variable different from the impulsivity; or residual effects of cannabis, not detected by the stop-signal task. In summary, this thesis emphasizes that cannabis use is a contributing factor to young drivers’ risky behaviours, regardless of their impulsivity. Moreover, cannabis users are not a homogeneous group, which is why it is important to specifically target problematic users in prevention campaigns.
287

Prise de risque à l'adolescence : l'influence du niveau d'incertitude et du contexte socio-émotionnel / Risk-taking in adolescence : influence of uncertainty level and socio-emotional context

Osmont, Anaïs 30 November 2015 (has links)
Afin de rendre compte de la spécificité des comportements à risque des adolescents, les modèles neurocognitifs récents ont proposé d'envisager la compétition entre deux systèmes caractérisés par des trajectoires développementales différentes : un système socio-émotionnel et un système de contrôle cognitif. En effet, l'engagement des adolescents dans des conduites à risque pourrait s'expliquer par une hypersensibilité émotionnelle exacerbée par des contextes sociaux saillant comme la présence de pairs, auquel s'ajoute une immaturité des processus de contrôle nécessaires à la régulation de ces émotions. Toutefois, l'ensemble de ces modèles négligent l'influence du niveau d'incertitude associées aux situations de prise de risque, alors même que les travaux de psychologie du développement témoignent de capacités différentes dans les situations de prise de décision à risque et les situations de prise de décision sous ambiguïté chez les adolescents. Ces derniers semblent en effet parfaitement capables d'intégrer des informations probabilistes et les enjeux associés aux différentes options, mais présentent des difficultés à décider avantageusement dès lors que ces informations ne sont plus directement disponibles mais doivent être inférées sur la base de leur propre expérience. Ainsi, l'objectif général de ce travail de thèse consistait à examiner l'influence du niveau d'incertitude et du contexte social sur la prise de risque à l'adolescence. Après avoir démontré dans une première étude que les adultes étaient massivement aversifs face aux situations associées à un manque d'information probabiliste, nous avons examiné la trajectoire développementale fine de ce phénomène d'aversion à l'ambiguïté chez l'enfant, l'adolescent et l'adulte. Cette étude contribue à définir l'aversion à l'ambiguïté comme une stratégie intuitive apparaissant progressivement au début de l'adolescence et mais suggère une aversion à l'ambiguïté aussi marquée chez les adolescents de 14-16 ans que chez les adultes. Ensuite, notre troisième étude avait pour objectif de clarifier l'impact du niveau d'information sur l'engagement des adolescents dans la prise de risque, à travers une comparaison directe entre des situations dites informées et non informées. Nos résultats démontrent que les adolescents présentent des difficultés à ajuster leurs réponses au niveau de risque dans les situations non-informées alors que la simple disponibilité d'indices concernant le niveau de risque les conduit à des performances similaires à celles des adultes. La réunion de nos trois premières études suggère ainsi que la prise de risque exacerbée des adolescents résulte davantage d'un déficit d'apprentissage basé sur les feedbacks, plutôt que d'une tendance générale à explorer les situations risquées ambigües. Face à ce constat, la quatrième étude visait à clarifier l'impact d'une influence sociale risquée ou prudente sur l'engagement des adolescents dans la prise de risque selon le niveau d'incertitude de la situation. Cette dernière étude nous a ainsi permis de souligner l'influence positive de l'expérience des pairs sur les conduites à risque des adolescents et de mettre en exergue le rôle spécifique de l'expérience d'autrui comme une information de nature sociale susceptible de compenser leur difficulté à apprendre sur la base de leur propre expérience. / In order to account for the characteristics of risk-taking specific to adolescence, new neurocognitive models presuppose a competition between two systems with distinct developmental trajectories: an emotional system and a top-down control system. Indeed, heightened risk-taking in adolescence could result from increased emotional sensitivity in socio-emotional contexts, including the presence of peers, combined with immature control processes underlying emotional regulation. Unfortunately, these models ignore the potential impact of varying levels of uncertainty in risky situations, despite advances in developmental psychology that suggest adolescent's capacities differ between risky decision-making and decision-making under ambiguity. Although adolescents are fully competent at evaluating probabilities and entertaining outcome likelihoods, they fail to make advantageous choices when such information is not directly available but must be inferred from their own experience. Thus, the overall aim of this thesis is to examine the impact of both the information level regarding risks and of the social-emotional context on risk-taking during adolescence. After showing in a first study that adults are largely ambiguity-averse in situations in which information is missing, we investigated the exact developmental trajectory of such ambiguity aversion in children, adolescents and adults. This second study characterizes ambiguity aversion as an affective strategy that gradually develops at the beginning of adolescence, while demonstrating that adolescents display an ambiguity aversion as much as adults. Then, study 3 aimed to clarify the influence of information level on adolescents' risk-taking behaviors by directly comparing informed and uninformed situations. Results showed that adolescents exhibit a suboptimal ability to adjust risk-taking to the risk level in the non-informed condition, but are efficient in making advantageous choices when explicit information is provided. Taken together, the first three studies suggest that heightened risk-taking in adolescence does not result from an increased ambiguity tolerance but rather from a specific impairment of feedback-based learning. Given adolescents' learning impairments in ambiguous situations, study 4 aimed to specify the impact of cautious or risky social influence on risk-taking behaviors, depending on the level of uncertainty. This final study underlies the potential positive influence of peers on risky behaviors. Peers4 experiences could play a particular role by providing social information that is likely to balance the difficulties adolescents have learning from their own experience.
288

How the quality of the early mother-infant relationship Influences decision making in risky situations later in life

Keane, Melissa 01 January 2014 (has links)
The present study examined attachment disorganization and executive function as predictors of adolescent risky behavior. Additionally, the present study examined how attachment disorganization and executive function may differentially predict adolescent risky behavior for males and females. Measures of executive function, mother-infant attachment, adolescent risky behavior, family income, and gender were obtained from adolescent participants of the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development (NICHD-SECCYD). Data was analyzed through structural equation modeling (SEM). Executive function, attachment, and risky behavior were unrelated in the study sample. Income was a significant predictor of attachment for females, but not males. Income was an equal and significant predictor of executive function for both males and females. Income was also a significant predictor of risky behavior for males and females, though a stronger predictor for females. Limitations and ideas for future research were discussed.
289

Criminal Involvement, Risky Sexual Behavior, Relationship Formation, and Fertility Outcomes

Ganser, Brittany 11 August 2023 (has links)
No description available.
290

[pt] ENSAIOS DE POLÍTICA MONETÁRIA COM ATIVOS ARRISCADOS / [en] ESSAYS IN MONETARY POLICY WITH RISKY ASSETS

EDUARDO GONCALVES COSTA AMARAL 29 December 2021 (has links)
[pt] Esta dissertação é composta por três capítulos que abordam questões relacionadas à política monetária. O Capítulo 1 avalia o problema de conduzir política monetária com ativos arriscados em um simples modelo neo-Wickselliano. Eu mostro que a potência da política monetária com relação a preços e inflação se reduz uma vez que ela só pode ser condicionalmente ativa na presença de risco subjacente ao ativo de política monetária. Além disso, prêmio de risco não compensado induz viés inflacionário, e há correlação positiva entre probabilidade de calote e inflação, do mesmo sinal que se costuma encontrar em dados empíricos. Esses resultados constituem um argumento novo em favor de uma política monetária mais vigilante em caso de crise fiscal ou política, o que ajuda a explicar o conservadorismo da política monetária em economias arriscadas. O capítulo 2 endogeniza risco no ativo de política monetária como risco fiscal e estuda sua transmissão. Eu desenvolvo um modelo novo-Keynesiano de dois agentes (TANK) com limites fiscais endógenos no qual o banco central opera através de títulos com risco de calote, e calibro para uma grande economia emergente, Brasil. Eu encontro que, ao ignorar o risco subjacente ao ativo de política monetária, o banco central reforça a coincidência desagradável de taxas mais altas de juros real, nominal e inflação na distribuição de equilíbrio do modelo, o que surge como o resultado de expectativas endógenas de recessões severas em caso de calote. Outrossim, acomodar risco de ativo de política induz correlação positiva entre risco de calote e inflação. Do ponto de vista de política, esses resultados lançam dúvidas quanto à correta avaliação da rigidez da política monetária em economias com risco de calote soberano, enquanto também lançam nova luz sobre a antiga discussão de por que a taxa básica de juros foi excepcionalmente alta no Brasil após o Plano Real. Finalmente, o Capítulo 3 responde à controvérsia recente sobre a presença, de fato, de um canal de transmissão de taxa de juros real nos modelos novo-Keynesianos, uma vez que adição de capital endógeno é consistente com a taxa real se movendo em qualquer direção após um choque monetário positivo. Eu mostro que esse problema de identificação pode ser contornado pela inclusão de outro ingrediente tão comum em modelos de tamanho médio quanto o próprio capital: suavização de taxa de juros. / [en] This dissertation presents three chapters addressing issues pertaining to monetary policy. Chapter 1 evaluates the problem of conducting monetary policy with risky assets in a simple neo-Wicksellian monetary model. I show that monetary policy s power w.r.t prices and inflation reduces as it can only be conditionally active in the presence of policy-asset risk. Moreover, uncompensated risk premium induces an inflationary bias, as well as default probability and inflation are positively correlated, the same sign of empirical correlations usually found. These results constitute a novel argument in favor of a more hawkish stance in case of a fiscal or political crisis, which helps to explain monetary policy conservatism in risky economies. Chapter 2 endogenizes policy-asset risk as a fiscal risk and studies its transmission. I lay out a two-agent New-Keynesian (TANK) model with endogenous fiscal limits in which the central bank operates through defaultable bonds, and then calibrate it to a large emerging economy, Brazil. I find that by ignoring policy-asset risk the central bank reinforces the unpleasant coincidence of higher inflation, real, and nominal interest rates in the equilibrium distribution of the model, what emerges as the result of endogenous expectations of a severe recession in case of default. Additionally, accommodating policy-asset risk induces positive correlation between default risk and inflation. From a policy perspective, these results raise serious concerns about the evaluation of monetary policy stance in default-risky economies, while shed new light on the long-standing discussion about why policy rates have been exceptionally high in Brazil after the Real Plan. Finally, Chapter 3 responds to a recent controversy on the actual presence of a real interest rate transmission channel in New-Keynesian models, as the addition of endogenous capital is consistent with real rates moving in any direction after a monetary shock. I show that this identification problem can be circumvented by the inclusion of another ingredient as prevalent as capital itself in middle-scale models: interest-rate smoothing.

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