De Invloed van Altruïsme op de Samenhang tussen Leeftijd en Mentale Veerkracht

Het primaire doel van deze studie was meer helderheid te krijgen over de invloed van altruïsme op de positieve associatie tussen leeftijd en mentale veerkracht. Het secundaire doel was een factor te kunnen aanwijzen die de positieve relatie tussen leeftijd en mentale veerkracht zou mediëren of anderszins verklaren. Meer begrip over factoren die samenhangen met mentale veerkracht, zou kunnen leiden tot de ontwikkeling en verfijning van trainingen ter bevordering van mentale veerkracht. De studie kende een cross-sectionele opzet met één meetmoment. Van de 92 oudere deelnemers werden er 66 met hulp van sleuteldeelnemers in het netwerk van de onderzoeker gevonden. De overige 26 zijn oudere deelnemers uit de database van de OU. Alle jongvolwassenen zijn afkomstig uit de database van de OU. In totaal zijn er 160 deelnemers geïncludeerd in deze studie, waarvan 68 jongvolwassenen tussen de 18 en 45 en 92 oudere volwassenen van 60 jaar of ouder. De uitgevoerde regressie analyses waren gericht op de veronderstelde mediërende verklaring door altruïsme van de relatie tussen leeftijd en mentale veerkracht. Mentale veerkracht werd gemeten met de Resilience Scale (RS-nl; Portzky, 2010). De Nederlandse vertaling van de NEO Five Factor Inventory (NEO-FFI; Hoekstra, Ormel & Fruyt, 1996) werd gebruikt om altruïsme te meten. Van de RS-nl is de totaalscore geanalyseerd, van de NEO zijn alleen de vragen met betrekking tot altruïsme geanalyseerd. De mediatie-analyse is uitgevoerd middels de 4 stappen methode van Baron en Kenny (beschreven in Verboon, 2010). De hypothese betreffende de positieve samenhang tussen leeftijd en mentale veerkracht werd bevestigd (b = .12, t(153) = 3.91, p < .001). Er werd geen samenhang tussen leeftijd en altruïsme of tussen altruïsme en mentale veerkracht gevonden. Hierdoor kon er geen sprake zijn van mediatie door altruïsme op de relatie tussen leeftijd en mentale veerkracht.

De Relatie tussen Angst- en Stemmingsklachten en Self-disclosure: het Effect van Emotie-inhibitie en Mindfulness

Angst- en stemmingsklachten worden geassocieerd met verminderde self-disclosure. Met self-disclosure wordt zelfonthulling van ervaren emoties bedoeld. Dit speelt een rol bij zelfacceptatie en zelfinzicht, en is belangrijk bij gesprekstherapie. Deze studie onderzocht of emotie-inhibitie de negatieve relatie tussen angst- en stemmingsklachten en self-diclosure verklaart, en of de relatie gunstig te beïnvloeden is door mindfulness. Het effect van mindfulness op deze relatie was nog niet eerder onderzocht. Deelnemers waren 99 vrouwen van 24 t/m 74 jaar (M = 44.60, SD = 10.55) en 26 mannen van 26 t/m 77 jaar (M = 48.27, SD = 12.68), afkomstig uit de normale Nederlands populatie. Het onderzoeksontwerp betrof een cross-sectioneel online vragenlijstonderzoek, waarbij gebruik gemaakt werd van de Symptom Checklist (Arrindel & Ettema, 1986), Emotional Self-Disclosure Scale (Snell, Miller, & Belk, 1988), Emotion Regulation Questionnaire (Gross & John, 2003) en Five Factor Mindfulness Questionnaire – Short Form (Bohlmeijer, Ten Klooster, Fledderus, Veehof, & Baer, 2011). Resultaten tonen, conform bestaande literatuur, dat angst- en stemmingsklachten negatief samenhangen met self-disclosure. Emotie-inhibitie heeft echter géén mediatie-effect en mindfulness heeft géén moderatie-effect op de negatieve relatie tussen angst- en stemmingsklachten en self-disclosure. Mindfulness heeft wel mediatie-effect op deze relatie. Mindfulness hangt hierbij positief samen met self-disclosure. De relevantie van de bevindingen is vooral praktisch: om mensen met angst- en stemmingsklachten te stimuleren over hun emoties te praten zou mindfulness aangewend kunnen worden.

Testing the psychometric properties of Kidscreen-27 with Irish children of low socio-economic status

Background

Kidscreen-27 was developed as part of a cross-cultural European Union-funded project to standardise the measurement of children’s health-related quality of life. Yet, research has reported mixed evidence for the hypothesised 5-factor model, and no confirmatory factor analysis (CFA) has been conducted on the instrument with children of low socio-economic status (SES) across Ireland (Northern and Republic).

Method

The data for this study were collected as part of a clustered randomised controlled trial. A total of 663 (347 male, 315 female) 8–9-year-old children (M = 8.74, SD = .50) of low SES took part. A 5- and modified 7-factor CFA models were specified using the maximum likelihood estimation. A nested Chi-square difference test was conducted to compare the fit of the models. Internal consistency and floor and ceiling effects were also examined.

Results

CFA found that the hypothesised 5-factor model was an unacceptable fit. However, the modified 7-factor model was supported. A nested Chi-square difference test confirmed that the fit of the 7-factor model was significantly better than that of the 5-factor model. Internal consistency was unacceptable for just one scale. Ceiling effects were present in all but one of the factors.

Conclusions

Future research should apply the 7-factor model with children of low socio-economic status. Such efforts would help monitor the health status of the population.

Méthodes de Bootstrap pour les modèles à facteurs

Cette thèse développe des méthodes bootstrap pour les modèles à facteurs qui sont couram- ment utilisés pour générer des prévisions depuis l'article pionnier de Stock et Watson (2002) sur les indices de diffusion. Ces modèles tolèrent l'inclusion d'un grand nombre de variables macroéconomiques et financières comme prédicteurs, une caractéristique utile pour inclure di- verses informations disponibles aux agents économiques. Ma thèse propose donc des outils éco- nométriques qui améliorent l'inférence dans les modèles à facteurs utilisant des facteurs latents extraits d'un large panel de prédicteurs observés. Il est subdivisé en trois chapitres complémen- taires dont les deux premiers en collaboration avec Sílvia Gonçalves et Benoit Perron. Dans le premier article, nous étudions comment les méthodes bootstrap peuvent être utilisées pour faire de l'inférence dans les modèles de prévision pour un horizon de h périodes dans le futur. Pour ce faire, il examine l'inférence bootstrap dans un contexte de régression augmentée de facteurs où les erreurs pourraient être autocorrélées. Il généralise les résultats de Gonçalves et Perron (2014) et propose puis justifie deux approches basées sur les résidus : le block wild bootstrap et le dependent wild bootstrap. Nos simulations montrent une amélioration des taux de couverture des intervalles de confiance des coefficients estimés en utilisant ces approches comparativement à la théorie asymptotique et au wild bootstrap en présence de corrélation sérielle dans les erreurs de régression. Le deuxième chapitre propose des méthodes bootstrap pour la construction des intervalles de prévision permettant de relâcher l'hypothèse de normalité des innovations. Nous y propo- sons des intervalles de prédiction bootstrap pour une observation h périodes dans le futur et sa moyenne conditionnelle. Nous supposons que ces prévisions sont faites en utilisant un ensemble de facteurs extraits d'un large panel de variables. Parce que nous traitons ces facteurs comme latents, nos prévisions dépendent à la fois des facteurs estimés et les coefficients de régres- sion estimés. Sous des conditions de régularité, Bai et Ng (2006) ont proposé la construction d'intervalles asymptotiques sous l'hypothèse de Gaussianité des innovations. Le bootstrap nous permet de relâcher cette hypothèse et de construire des intervalles de prédiction valides sous des hypothèses plus générales. En outre, même en supposant la Gaussianité, le bootstrap conduit à des intervalles plus précis dans les cas où la dimension transversale est relativement faible car il prend en considération le biais de l'estimateur des moindres carrés ordinaires comme le montre une étude récente de Gonçalves et Perron (2014). Dans le troisième chapitre, nous suggérons des procédures de sélection convergentes pour les regressions augmentées de facteurs en échantillons finis. Nous démontrons premièrement que la méthode de validation croisée usuelle est non-convergente mais que sa généralisation, la validation croisée «leave-d-out» sélectionne le plus petit ensemble de facteurs estimés pour l'espace généré par les vraies facteurs. Le deuxième critère dont nous montrons également la validité généralise l'approximation bootstrap de Shao (1996) pour les regressions augmentées de facteurs. Les simulations montrent une amélioration de la probabilité de sélectionner par- cimonieusement les facteurs estimés comparativement aux méthodes de sélection disponibles. L'application empirique revisite la relation entre les facteurs macroéconomiques et financiers, et l'excès de rendement sur le marché boursier américain. Parmi les facteurs estimés à partir d'un large panel de données macroéconomiques et financières des États Unis, les facteurs fortement correlés aux écarts de taux d'intérêt et les facteurs de Fama-French ont un bon pouvoir prédictif pour les excès de rendement.

Estudo Preliminar das Propriedades Psicométricas do Inventário de Lateralidade de Edinburgh numa Amostra de Adultos da População Portuguesa

Introdução: A lateralidade é a diferença na capacidade de controlo entre os dois lados do corpo. Os métodos utilizados para avaliar a lateralidade manual incluem a observação efetiva do uso do membro dominante ou a aplicação de inventários respondidos pelo próprio indivíduo avaliado. O Inventário de Lateralidade de Edinburgh (EHI) é o instrumento mais utilizado para avaliar a lateralidade manual. Apesar do seu uso amplo, em Portugal não existem estudos que avaliem a sua validade e fidedignidade. Objetivos: Estudar as propriedades psicométricas do Inventário de Lateralidade de Edinburgh numa amostra da população portuguesa. Métodos: A amostra é constituída por 290 pessoas (135 homens e 155 mulheres), com idades compreendidas entre os 18 e os 65 anos. Todos os participantes preencheram uma declaração de consentimento informado e uma bateria de testes neuropsicológicos Resultados: A média no EHI foi de 62,36 (DP = 38,00). Os resultados demonstraram que das seis variáveis sociodemográficas (idade, sexo, escolaridade, zona de residência, regiões e profissão) três apresentaram ter influência significativa nas pontuações do EHI: idade, zona de residência e regiões. A confiabilidade e a estabilidade temporal do EHI apresentaram resultados adequados. A análise fatorial confirmatória mostrou que o modelo não é melhor explicado por um fator. Para dois fatores o modelo continua a não ser adequado. Conclusão: Apesar de termos obtido uma boa consistência interna não nos é possível considerar este teste como o mais adequado para medir o constructo da lateralidade. / Introduction: The handedness is the difference in the control capacity between the two sides of the body. The methods used to evaluate the manual handedness include the effective observation of the use of dominant member or application of inventories answered by the person assessed. The Edinburgh Handedness Inventory (EHI) is the most used to evaluate manual handedness. Even though being widely used, in Portugal there are no studies that measure its validity and reliability. Objective: To study the psychometric properties of Edinburgh Handedness Inventory in a Portuguese sample. Methods: The sample consists of 290 people (135 men and 155 women), aged between 18 and 65 years. All participants filled an informed consent form and a battery of neuropsychological tests. Results: The average in EHI was 62.36 (SD = 38.00). The results showed that 3 of 6 sociodemographic variables showed significant influence in EHI scores. The reliability and temporal stability of EHI were adequate. Confirmatory factor analysis showed that the model is not better explained by one factor. A two-factor model was not also suitable. Conclusion: Even though we got a good internal consistency we cannot consider this test as the most appropriate for measuring the handedness construct.

A Personalidade e os Sintomas Psicopatológicos numa Amostra de Estudantes de Psicologia

Atualmente, as investigações acerca da personalidade e dos sintomas psicopatológicos, nos estudantes de Psicologia, parecem ser escassas. De modo a que nos pareceu interessante perceber um pouco mais sobre estas personalidades e sobre os sintomas psicopatológicos adjacentes aos mesmos. Assim sendo, o presente estudo teve como objetivo definir o perfil dos estudantes de Psicologia, explorando as variáveis: personalidade, sintomas psicopatológicos e a relação destas com as variáveis sociodemográficas sexo e anos de curso. Para que este estudo se pudesse realizar, foram inquiridos 240 estudantes, do primeiro e segundo ciclo de Psicologia, pertencentes a Instituições de Ensino Públicas e Privadas do Centro e Norte do País. O questionário foi enviado pelas escolas, sob a forma de hiperligação e foi composto pelo Inventário dos Cinco Fatores de Personalidade (NEO-FFI), pelo Inventário dos Sintomas Psicopatológicos (BSI) e pelo Questionário Sociodemográfico, formulado pelo investigador. No NEO-FFI, verificámos que a Conscienciosidade é a dimensão da personalidade mais predominante. E no BSI, averiguámos que a Depressão e o Psicoticismo foram os sintomas psicopatológicos que apresentaram valores médios mais elevados. Na comparação entre sexos pudemos observar que existem diferenças significativas na dimensão da personalidade Abertura à Experiência (NEO-FFI) e na Sensibilidade Interpessoal e Ideação Paranóide (BSI). Em ambos os instrumentos, pudemos observar, também, que o sexo masculino tende a apresentar valores mais elevados em comparação ao sexo feminino. Em suma, neste projeto de investigação encontrámos alguns resultados similares a estudos anteriores e, também, alguns dados que nos despertam a curiosidade e suscitam interesse para futuras investigações. / Nowadays, investigations about personality and psychopathological symptoms on Psychology students seem to be scarce. Because of that it seemed interesting to us to learn more about these personalities and about the psychopathological symptoms behind them. For that reason, the main purpose of the present study was to explore the profile of psychology students in what concerns personality, psychopathological symptoms and their relation with gender and years of graduation. We inquired 240 students, studying in public and private institutions from the centre and north of Portugal, and used three instruments: the NEO Five-Factor Inventory (NEO-FFI), The Brief Symptoms Inventory (BSI) and a Social-Demographic Questionnaire created by the investigator. The results showed that in the NEO-FFI, Conscientiousness was the most predominant dimension. Regarding the BSI, we found that Depression and Psychoticism were the symptoms that presented higher values. In what concerns gender, there was significant differences in the dimension Openness to Experience (NEO-FFI) and in Interpersonal Sensitivity and Paranoid Ideation (BSI). In both instruments there was a tendency to male students score higher than female students. In conclusion, we found some results that are similar to previous studies and also found some indicators that raise curiosity for further investigation on the profile of psychology students.

Estudo Preliminar das Propriedades Psicométricas e dos Dados Normativos da Forma Geral das Matrizes Progressivas de Raven numa Amostra da Comunidade

Objetivo: Estudar as propriedades psicométricas e os dados normativos da Forma Geral das Matrizes Progressivas de Raven numa amostra da comunidade da população portuguesa. Método: A amostra é constituída por 697 pessoas (314 homens e 383 mulheres), com idades compreendidas entre os 12 e os 90 anos. Todos os participantes preencheram uma declaração de consentimento informado e uma bateria de testes neuropsicológicos, incluindo a Forma Geral das Matrizes Progressivas de Raven (FG-MPR), Teste de Memória de 15-Item de Rey, Escala de Autoavaliação de Ansiedade de Zung, Bateria de Avaliação Frontal e Figura Complexa de Rey. Resultados: A média na FG-MPR foi de 44,47 (DP = 10,78). Os resultados demonstraram que todas as variáveis sociodemográficas (idade, sexo, escolaridade, profissão, regiões e tipologia de áreas urbanas), exceto o estado civil, apresentaram ter influência significativa nas pontuações da FG-MPR. A confiabilidade e a estabilidade temporal da FG-MPR revelaram-se adequadas. A análise fatorial exploratória e confirmatória mostrou que o modelo para um fator não é adequado. Um modelo a quatro fatores continua a não ser adequado. Conclusão: Os dados do presente estudo sugerem que se trata de um instrumento com potencialidades na sua utilização junto da população portuguesa. / Purpose: To study the psychometric properties and date normative of the Raven’s Standard Progressive Matrices in a Portuguese community sample. Method: The sample consists of 697 people (314 men and 383 women), aged between 12 and 90 years. All participants filled an informed consent form and a battery of neuropsychological tests, which included Raven’s Standard Progressive Matrices (RSPM), Rey 15-Item Memory Test, Zung Self-Rating Anxiety Scale, Frontal Assessment Battery, and Rey Complex Figure Test. Results: The average in RSPM was 44.47 (SD = 10.78). The results showed that all of the sociodemographic variables (age, sex, education, profession, region, and typology of urban areas), with the exception of civil status, showed significant influence on RSPM scores. The reliability and temporal stability of RSPM were adequate. Exploratory and Confirmatory factor analysis showed that the model is not better explained by one factor. A two-factor model was not also suitable. Conclusion: The data from this study suggest that it is an instrument with potential for its use among the Portuguese population.

Future Earnings Growth Volatility and the Value Premium

The value premium is well established in empirical asset pricing, but to date there is little understanding as to its fundamental drivers. We use a stochastic earnings valuation model to establish a direct link between the volatility of future earnings growth and firm value. We illustrate that risky earnings growth affects growth and value firms differently. We provide empirical evidence that the volatility of future earnings growth is a significant determinant of the value premium. Using data on individual firms and characteristic-sorted test portfolios, we also find that earnings growth volatility is significant in explaining the cross-sectional variation of stock returns. Our findings imply that the value premium is the rational consequence of accounting for risky earnings growth in the firm valuation process.

Validation Française de l’Échelle de la Personnalité Temporelle (French Validation of the Time Personality Indicator)

RÉSUMÉ Certains auteurs ont développé un intérêt pour la compréhension des aptitudes associées à la gestion du temps. Ainsi, plusieurs définitions théoriques ont été proposées afin de mieux cerner ce concept et une multitude de questionnaires a été développée afin de le mesurer. La présente étude visait à valider la traduction française d’un de ces outils, soit le Time Personality Indicator (TPI). Des analyses exploratoires et confirmatoires ont été effectuées sur l’ensemble des données recueillies auprès de 1 267 étudiants et employés de l’Université Laval ayant complété la version française du TPI ainsi que d’autres mesures de la personnalité. Les résultats ont révélé qu’une solution à huit facteurs permet de mieux décrire les données de l’échantillon. La discussion présente les raisons pour lesquelles la version française du TPI est valide, identifie certaines limites de la présente étude et souligne l’utilité de cet outil pour la recherche sur la gestion du temps. (ABSTRACT: Numerous authors have developed an interest towards the understanding of the abilities related to time management. As a consequence, multiple theoretical definitions have been proposed to explain time management. Likewise, several questionnaires have been developed in order to measure this concept. The aim of this study was to validate a French version of one of these tools, namely the Time Personality Indicator (TPI). The French version of the TPI and other personality questionnaires were completed by 1267 students and employees of Université Laval. The statistical approach used included exploratory and confirmatory analyses. Results revealed that an eight factor model provided a better adjustment to the data. The discussion provides arguments supporting the validity of the French version of the TPI and underlines the importance of such a tool for the research on time management)

Strategisk kompetensutveckling : En organisations strategiska förhållningssätt till kompetensutveckling

I denna fallstudie undersöks hur en kompetensbaserad personalstrategi ter sig inom en organisation. Då det är ett brett område har en avgränsning gjorts och det är enbart kompetensutveckling som berörs. Syftet är att skapa förståelse för det strategiska förhållningssättet till kompetensutveckling inom en organisation. Inom ramen för våra forskningsfrågor undersöks också de verktyg och metoder som en organisation använder sig av för att utveckla rätt kompetens samt de hinder och utmaningar som finns. Det har av tidigare forskning framkommit att ett strategiskt förhållningssätt är avgörande för en organisations överlevnad och framgång. Det finns en samstämmighet kring att organisationer vid valet av kompetensutvecklingsinsatser behöver utgå från verksamhetens behov, kundkrav och framtida mål för att bli gynnsamma. Syftet för insatserna blir därmed avgörande och en central del i det strategiska förhållningssättet till kompetensutveckling. Studien utgår från en fenomenologisk ansats och insamling av data har skett med hjälp av sju semi-strukturerade intervjuer med öppna frågor som utgått från tydliga teman. Studiens intervjuer har genomförts i en politiskt styrd organisation med cirka 5000 anställda och analysen av dessa intervjuer har skett enligt en femstegsmodell där vi avsett att synliggöra de mest väsentliga beståndsdelarna av fenomenet. Studien har tydliggjort hur organisationens strategiska förhållningssätt ser ut och också tydligt påvisat faktorer som gör det svårt att upprätthålla. De verktyg och metoder organisationen använder sig av är exempelvis webbaserad utbildning, ständiga förbättringar, nätverk, händelsehanteringssystem, en utbildningsplattform samt ett formulär för utbildningsförfrågningar. De hinder och utmaningar som synliggjorts är exempelvis utomstående faktorer, ekonomi, ansvarsfördelning och samverkan. Vår studie har också bidragit till en insikt i hur viktigt det är att noga överväga vilken metod som bör användas vid olika typer av kompetensutvecklingsinsatser. Det är viktigt att inte låta fokus hamna på att genomföra det minst kostsamma, utan låta valet av metod syfta till att ge det mest effektiva lärandet. Det är viktigt att i varje skede göra strategiska avvägningar som inte enbart har sin grund i ekonomiska perspektiv vad gäller besparingar och minskade kostnader. Ett intressant område till vidare forskning ser vi i chefsperspektivet. Vi finner detta intressant då det både genom tidigare forskning och genom vår egen studie tydligt har framgått att chefer har en nyckelroll och det finns därför ett intresse att närmre undersöka den roll som chefer delegeras i kompetensutvecklingsinsatser och vilka möjligheter de har i arbetet med dessa frågor.

Musik - påverkan vid demenssjukdom : En litteraturöversikt

Bakgrund: Demens är en progressiv sjukdom och antalet personer som får en demensdiagnos kommer inom några årtionden öka drastiskt. Sjukvården behöver komma fram med nya icke-farmakologiska metoder för att kunna hantera den stora ökningen av personer med demenssjukdom. Syfte: Syftet var att beskriva om och på vilket sätt musiken påverkar personer med demens. Metod: Litteraturöversikt med induktiv ansats där artiklar med kvalitativ och kvantitativ metodik sammanställdes. Artikelsökning gjordes i databaserna Cinahl samt PsychInfo. De kvalitativa artiklarna analyserades med hjälp av Fribergs femstegsmodell och statistiken från de kvantitativa artiklarna sammanställdes i en tabell. Resultat: Det kvantitativa resultatet visade att musik hade en effekt med statistiskt signifikant skillnad på flera av de undersökta variablerna. Agitation och oro/ ångest minskade medan positivt engagemang/ deltagande ökade. Det kvalitativa resultatet genererade tre teman: kommunikation, sinnesstämning samt indirekt påverkan. Kommunikationen förbättrades, personer med demens upplevde glädje och personalen påverkades positivt av musiken vilket ledde till indirekt påverkan på personer med demens. Slutsats: Musik är en enkel och kostnadseffektiv intervention att använda sig av när det gäller personer med demens. Olika musikinterventioner kan användas vid olika situationer för att få den effekt som önskas. Det är även ett enkelt sätt att komma personer med demens närmare och få en större förståelse.

Stigmatisering - Personers upplevelser av att leva med HIV/AIDS

Bakgrund: HIV är en infektionssjukdom som kan överföras vid bland annat oskyddade samlag, via blod och transplanterad vävnad. Då det idag finns antivirala läkemedel ses HIV inte längre som en dödlig utan en kronisk sjukdom. Personer med HIV/AIDS upplever att sjukdomen påverkar den fysiska och psykiska hälsan negativt. Sjuksköterskor har bristande kunskaper om sjukdomen samt är ovilliga att ge omvårdnad till dessa personer. Syfte: Syftet med litteraturöversikten var att beskriva personers upplevelser av att leva med HIV/AIDS. Metod: Litteraturöversikten baserades på 13 artiklar med kvalitativ design som analyserades enligt Fribergs femstegsmodell. En induktiv ansats användes. Resultat: Huvudtemat stigmatisering identifierades tillsammans med temat transition med tillhörande fem underteman samt temat rädsla med tillhörande tre underteman. Slutsats: Personerna med HIV/AIDS upplevde sig stigmatiserade av närstående, i samhället och i kontakt med hälso- och sjukvården. För att stigmatiseringen ska upphöra behöver sjuksköterskor mer kunskap om HIV/AIDS. För att nå ett personcentrerat förhållningssätt behöver sjuksköterskor se personerna bakom sjukdomen samt medvetandegöra sina attityder och förutfattade meningar mot personerna som lever med HIV/AIDS.

Essays on the term structure of interest rates

This PhD thesis contains three main chapters on macro finance, with a focus on the term structure of interest rates and the applications of state-of-the-art Bayesian econometrics. Except for Chapter 1 and Chapter 5, which set out the general introduction and conclusion, each of the chapters can be considered as a standalone piece of work. In Chapter 2, we model and predict the term structure of US interest rates in a data rich environment. We allow the model dimension and parameters to change over time, accounting for model uncertainty and sudden structural changes. The proposed timevarying parameter Nelson-Siegel Dynamic Model Averaging (DMA) predicts yields better than standard benchmarks. DMA performs better since it incorporates more macro-finance information during recessions. The proposed method allows us to estimate plausible realtime term premia, whose countercyclicality weakened during the financial crisis. Chapter 3 investigates global term structure dynamics using a Bayesian hierarchical factor model augmented with macroeconomic fundamentals. More than half of the variation in the bond yields of seven advanced economies is due to global co-movement. Our results suggest that global inflation is the most important factor among global macro fundamentals. Non-fundamental factors are essential in driving global co-movements, and are closely related to sentiment and economic uncertainty. Lastly, we analyze asymmetric spillovers in global bond markets connected to diverging monetary policies. Chapter 4 proposes a no-arbitrage framework of term structure modeling with learning and model uncertainty. The representative agent considers parameter instability, as well as the uncertainty in learning speed and model restrictions. The empirical evidence shows that apart from observational variance, parameter instability is the dominant source of predictive variance when compared with uncertainty in learning speed or model restrictions. When accounting for ambiguity aversion, the out-of-sample predictability of excess returns implied by the learning model can be translated into significant and consistent economic gains over the Expectations Hypothesis benchmark.

Essays on the term structure of interest rates

This PhD thesis contains three main chapters on macro finance, with a focus on the term structure of interest rates and the applications of state-of-the-art Bayesian econometrics. Except for Chapter 1 and Chapter 5, which set out the general introduction and conclusion, each of the chapters can be considered as a standalone piece of work. In Chapter 2, we model and predict the term structure of US interest rates in a data rich environment. We allow the model dimension and parameters to change over time, accounting for model uncertainty and sudden structural changes. The proposed time-varying parameter Nelson-Siegel Dynamic Model Averaging (DMA) predicts yields better than standard benchmarks. DMA performs better since it incorporates more macro-finance information during recessions. The proposed method allows us to estimate plausible real-time term premia, whose countercyclicality weakened during the financial crisis. Chapter 3 investigates global term structure dynamics using a Bayesian hierarchical factor model augmented with macroeconomic fundamentals. More than half of the variation in the bond yields of seven advanced economies is due to global co-movement. Our results suggest that global inflation is the most important factor among global macro fundamentals. Non-fundamental factors are essential in driving global co-movements, and are closely related to sentiment and economic uncertainty. Lastly, we analyze asymmetric spillovers in global bond markets connected to diverging monetary policies. Chapter 4 proposes a no-arbitrage framework of term structure modeling with learning and model uncertainty. The representative agent considers parameter instability, as well as the uncertainty in learning speed and model restrictions. The empirical evidence shows that apart from observational variance, parameter instability is the dominant source of predictive variance when compared with uncertainty in learning speed or model restrictions. When accounting for ambiguity aversion, the out-of-sample predictability of excess returns implied by the learning model can be translated into significant and consistent economic gains over the Expectations Hypothesis benchmark.

Diversity and path coefficient analysis of Southern African maize hybrids

Detailed knowledge on genetic diversity among germplasm is important for hybrid maize ( Zea mays L.) breeding. The objective of the study was to determine genetic diversity in widely grown hybrids in Southern Africa, and compare effectiveness of phenotypic analysis models for determining genetic distances between hybrids. Fifty hybrids were evaluated at one site with two replicates. The experiment was a randomized complete block design. Phenotypic and genotypic data were analyzed using SAS and Power Marker respectively. There was significant (p < 0.01) variation and diversity among hybrid brands but small within brand clusters. Polymorphic Information Content (PIC) ranged from 0.07 to 0.38 with an average of 0.34 and genetic distance ranged from 0.08 to 0.50 with an average of 0.43. SAH23 and SAH21 (0.48) and SAH33 and SAH3 (0.47) were the most distantly related hybrids. Both single nucleotide polymorphism (SNP) markers and phenotypic data models were effective for discriminating genotypes according to genetic distance. SNP markers revealed nine clusters of hybrids. The 12-trait phenotypic analysis model, revealed eight clusters at 85%, while the five-trait model revealed six clusters. Path analysis revealed significant direct and indirect effects of secondary traits on yield. Plant height and ear height were negatively correlated with grain yield meaning shorter hybrids gave high yield. Ear weight, days to anthesis, and number of ears had highest positive direct effects on yield. These traits can provide good selection index for high yielding maize hybrids. Results confirmed that diversity of hybrids is small within brands and also confirm that phenotypic trait models are effective for discriminating hybrids.