The main idea of this thesis is studying the importance of the carry-over effects and interaction effects in statistical models. To investigate it, a hand-milking experiment in Burkina Faso was studied. In many no electricity access countries, such as Burkina Faso, the amount of milk and milk compositions are still highly  relying on hand-milking techniques and milkers. Moreover, the time effects also plays a important role in stockbreeding system. Therefore, falling all effects, carry-over effects and interaction effects into a linear mixed effects model, it is concluded that the carry-over effects of milker and hand-milking techniques cannot be neglected, and the interaction effects among hand-milking techniques, different milkers, days and periods can be substantial.

This paper contributes to the field of research on entrepreneurship and self-employment. More explicitly, it contributes to the research regarding heterogeneity by studying the ‘necessity’ self-employed. In this paper, we question the notion of ‘necessity’ and its connection to weak labour market attainment by measuring individual’s human capital in relation to local labour market structures. The used data derives from relevant labour market data combined with data from a postal survey study conducted in 2011, containing self-employed between the age 25–64. The results show no connection between labour market attainment and ‘necessity’ self-employment. The results however indicate a correlation between sociodemographic-aspects and ‘necessity’ self-employment.

Denna studie och uppsats har behandlat och fokuserats på att synliggöra interaktionseffekten som uppstår när ett informationssystems gränssnitt är avskalat. Fallstudien i denna uppsats utgår ifrån ett webbaserat skrivverktyg vid namn Writer. Syftet med studien har varit att tydliggöra interaktionseffekten vid personligt handlande i en interaktiv användningssituation och hur det i sin tur påverkar användarupplevelsen. Studiens teoretiska område och ramverk är Handlingsbarhet där fokus har varit på den interaktiva handlingsnivån i koppling till den grundläggande interaktionsloopen. Den grundläggande interaktionsloopen består av fyra steg där en användare frågar, gör får ett svar och sedan utvärderar. I koppling till teorin har fem interkationskriterier för teorin inkorporerats som dessa är; Tydlig handlingsrepertoar, Känd & begriplig vokabulär, Handlingstransparens, Tydlig feedback och Ändringsbarhet . Dessa fem kriterier har varit tematiseringen för det empiriska arbetet. Genom både det målinriktade urvalet och snöbollsurvalet har sex journalister/skribenter involverats för att samla in data. I metodarbetet genomfördes användartest på skrivverktyget med uppgifter som utformats i enlighet med de fem interaktionskriterierna. Efter detta användartest fick samtliga informanter utvärdera upplevelsen och göra tretton ställningstaganden utifrån ett användarupplevelse-frågeformulär där begrepp såsom lätt att lära sig/inte lätt att lära sig och effektiv/ineffektiv efterfrågades. Efter dessa två moment utfördes semistrukturerade intervjuer med femton framtagna frågor som också dem baserats på de fem interaktionskriterierna. För att analysera den insamlade datan tillämpades metoden innehållsanalys som resulterade i 25 kategorier med tillhörande beskrivningar och citat. Utifrån innehållsanalysen och dess resultat analyserades kategorierna i jämförelse med modellen D.EU.PS och dess 18 klasser baserat på deras definition. Detta mynnade i sin tur ut i tio stycken interaktionseffekter baserat på sju klasser. Resultatet och de tio effekterna är: Säkerhet, Tidigare referenser, Terminologi, Igenkännelse, Förståelse för sekvens/handling, Uppfattning, Enkelhet, Effektivitet Tillgänglighet och Gruppering (närhet). Utifrån det personliga handlandet som perspektiv är dessa effekter ett resultat av ett avskalat skrivverktyg som bidrar till en god användarupplevelse. / This thesis and report has addressed and focused on identifying the interaction effect that occurs when an information system's interface is scaled off and is minimalistic. This case study is based on a web-based writing tool called Writer. The purpose of the research has been to clarify the personal interaction effect in an interactive usage situation and how it in turn affects the user experience. The theoretical field and framework of the study is Actability , focusing on the interactive action level in connection with The Elementary InterAction Loop . The Elementary InterAction Loop consists of four steps where the user asks, does, gets an answer and then evaluates. In conjunction with the theory, five interaction criteria have been incorporated, which are; Clear Action Repertoire , Intelligible Vocabulary , Action Transparency , Clear Feedback , and Amendability . These five criteria have been the thematization of the empirical work. Through both targeted selection and snowball sampling, six journalists/writers have been involved in collecting data. In the method work, user test was performed on the writing tool with tasks formulated in accordance to the five interaction criteria. In the method work, user tests was performed on the writing tool. Thereafter the tasks was formed according to the five interaction criteria from the theoretical framework. All informants evaluated their experience and made thirteen statements based on a user experience questionnaire where concepts such as easy to learn/not easy to learn and effective/ineffective were asked for. Following these two steps in the empirical study, semi-structured interviews were conducted with fifteen questions based on the five interaction qualities. In order to analyze the collected data, the content analysis method was applied which resulted in 25 categories with descriptions and quotes. Based on a content analysis and its results, the categories were then analyzed using the D.EU.PS model and its 18 classes. The analysis resulted in ten interaction effects placed in seven different classes. The result and the ten interaction effects are: Security, Previous references, Terminology, Recognition, Understanding of sequence/action, Perception, Simplicity, Efficiency Availability and Grouping (proximity). Based on personal behavior as a perspective, these effects are the result of a minimalistic writing tool that contributes to a good user experience.

I samband med åldrandet ses ofta en försämring av människors kognitiva förmågor, däribland det episodiska minnet, vilket är avgörande för vardagligt fungerande och livskvalitén för äldre. Livsstilsfaktorer som fysisk aktivitet (FA) och övervikt har tidigare kopplats till hälsosamt åldrande och visat sig påverka graden av försämring. Hur FA och övervikt interagerar på lång sikt för att påverka det episodiska minnet för äldre behöver dock fortfarande utredas. Denna studie undersökte både de enskilda effekterna av FA och övervikt på det episodiska minnet, samt hur dessa faktorer interagerar på lång sikt. Därtill undersöktes skillnader mellan sjuka och friska äldre deltagare. Data från deltagare (n = 5 287) i the English Longitudinal Study on Aging i åldrarna 50 och äldre användes i ett longitudinellt upplägg. Självskattade mått på FA och viktstatus från en tidpunkt användes för att predicera poäng på ett minnestest vid en tidpunkt fyra år senare, med och utan kontrollvariabler. Statistiskt signifikanta effekter av FA på minne kunde ses både med och utan kontrollvariabler, men tydliga effekter av övervikt kunde inte ses. Interaktioner mellan övervikt och FA kunde endast upptäckas i modeller utan kontrollvariabler, och inte alls i modeller med enbart sjuka deltagare. Slutsatser om överviktens påverkan på det episodiska minnet kunde inte dras, men resultatet ger vidare stöd till att FA hjälper till att bevara minnet i åldrandet. Sammantaget förklarades dock mer av variansen i episodiskt minne av kontrollvariabler som ålder och utbildningsnivå. / With aging often comes declining cognitive function, with episodic memory being one of the declining factors crucial for everyday functioning and quality of life among the elderly. Lifestyle factors such as physical activity (PA) and overweight have been associated with healthy aging and the trajectory of the decline. How PA and overweight interact in affecting episodic memory over time among the elderly is, however, still in need of further investigation. The present thesis investigated both the direct effects of PA and overweight on episodic memory, and how the interaction between these factors affect episodic memory. Furthermore, differences in the effects between participants with or without illnesses were examined. Data from participants (n = 5 287) in the English Longitudinal Study on Aging aged 50 and older were used in a longitudinal design. Self-reported measures of PA as well as measures of weight- status from time point 1 was used to predict scores on a memory test at a second time point, four years later, with and without control variables. Statistically significant effects of PA on memory score were detected, both with and without control variables. No statistically significant effects of overweight were detected. Interactions between overweight and PA could only be detected in models without control variables, and not at all among participants with illnesses. Conclusions on the effect of overweight on episodic memory could not be reached, but further support is lent to PA’s role in preserving memory function in aging. In closing more of the variance in episodic memory was attributed to other factors such as increasing age and higher education levels.

Thesis (PhD)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Mycobacterium tuberculosis, the causative agent of tuberculosis disease, contains five copies of the ESAT-6 gene cluster, each encoding a dedicated ESX protein secretion system which has been defined as a novel Type-VII secretion system. The ESX have been implicated in virulence and survival of M. tuberculosis, and as such present a promising target for novel treatment interventions. This study has investigated the evolution, regulation, functions and substrates of the ESX secretion systems. The evolutionary history of the ESX secretion systems was established using in silico and phylogenetic analyses of the sequenced mycobacteria, closely related actinomycetes and WXG-FtsK clusters from other bacteria. The ESX-4 gene cluster appears to have evolved with the start of the evolution of the mycomembrane, followed by the duplication of ESX-3, which marks the evolution of the genus Mycobacterium. The ESX-1 duplication occurred next, followed by ESX-2 and ESX-5 which occur only in the slow growing mycobacteria. Five additional ESX gene clusters were newly identified and named ESX-P1 to - P5. These additional ESX clusters occur, or are predicted to occur, on plasmid DNA, and appear to be progenitors of the genomic ESX-1 to -5 gene clusters, possibly indicating a plasmid-mediated mechanism of ESX duplication and evolution. The promoters expressing the M. tuberculosis ESX-1 to ESX-5 secretion systems were investigated using a promoter probe assay, and characterised using in silico analyses. Promoters were identified for ESX-1, -2, -3 and -5. The functions of the mycobacterial ESX secretion systems were investigated using whole proteomic, secretomic and metabolomic analyses of the fast growing, non-pathogenic M. smegmatis, which contains three of the ESX secretion systems, ESX-1, 3, and 4. ESX knockout strains of M. smegmatis were generated and used in comparative analyses with wild-type M. smegmatis. ESX-1 was highly expressed in wild-type M. smegmatis, however no specific pathways showed considerable variation when ESX-1 was deleted. Deletion of ESX-3 resulted in substantial variation to multiple cellular pathways, including amino acid, carbohydrate and fatty acid metabolism and oxidative stress. These and other differences indicate possible perturbed polyamine metabolism in the absence of ESX-3. Although no ESX-4 protein components were detected in wild type M. smegmatis, the ESX-4 knockout displayed substantial proteomic variation. Reduced levels of ESX-3 component proteins in the ESX-4 knockout suggest that ESX-4 influences ESX-3 expression. Other variation linked ESX-4 to cell division and molybdenum metabolism. Secretomic analyses of wild-type and ESX knockout M. smegmatis strains were used to search for novel substrates of the M. smegmatis ESX secretion systems. No prototype ESX substrates were identified in the culture filtrates, however 10 possible substrates of the ESX-1, -3 and -4 secretion systems, containing the general ESX secretion signal, YxxxD/E, were identified. The functions of some of these proteins correlate with the ESX functions identified in the proteomic and metabolomic analyses. This study sets the groundwork for future work in understanding the functional roles and expression patterns of these ESX secretion systems and in using global proteomic and metabolomic analyses to understand cellular changes in response to specific signals or genomic changes. / AFRIKAANSE OPSOMMING: Mycobacterium tuberculosis, die veroorsakende agent van tuberkulose, bevat vyf kopieë van die ESAT-6 geengroep, wat elk 'n toegewyde ESX proteïen sekresiesisteem, omskryf as 'n nuwe Tipe-VII sekresiestelsel, kodeer. Die ESX sekresiesisteme is betrokke by virulensie en oorlewing van M. tuberculosis, en is dus belowende teikens vir nuwe behandelings. Hierdie studie het die evolusie, regulasie, funksies en substrate van die ESX sekresiesisteme ondersoek. Die evolusionêre geskiedenis van die ESX sekresiesisteme is bepaal met behulp van in silico en filogenetiese analises van die volgordebepaalde mikobakterieë, nouverwante actinomisete en WXG-FtsK groepe van ander bakterieë. Die ESX-4 geengroep het saam met die evolusie van die mikomembraan ontwikkel, gevolg deur die duplisering van ESX-3, wat die evolusie van die genus Mycobacterium merk. Die ESX-1 duplisering het volgende plaasgevind, gevolg deur ESX-2 en ESX-5, wat slegs in die stadiggroeiende mikobakterieë voorkom. Vyf addisionele ESX geengroepe is nuut geïdentifiseer in hierdie studie en is ESX-P1 tot -P5 genoem. Hierdie addisionale ESX groepe is op, of word voorspel om op, plasmied DNS voor te kom, en mag voorlopers van die genomiese ESX-1 tot -5 geengroepe wees, wat moontlik dui op 'n plasmied-gemedieërde meganisme van ESX duplisering en evolusie. Die promoters wat verantwoordelik is vir die uitdrukking van die M. tuberculosis ESX-1 tot ESX-5 sekresiesisteme is ondersoek deur middel van 'n promoter aktiwiteitstoets, en gekarakteriseer deur in silico analises. Promoters is geidentifiseer vir ESX-1, -2, -3 en -5. Die funksies van die mikobakteriële ESX sekresiesisteme is ondersoek deur proteomiese, sekretomiese en metabolomiese analises van die vinnig-groeiende, nie-patogeniese mikobakterium M. smegmatis, wat ESX- 1, -3 en -4 sekresiesisteme besit. ESX uitslaanmutante van M. smegmatis is gegenereer en gebruik in die vergelykende analises met die wilde-tipe M. smegmatis. ESX-1 is hoogs uitgedruk in wilde-tipe M. smegmatis, maar geen spesifieke metabolise weë het aansienlike variasie getoon wanneer ESX-1 verwyder is. Delesie van ESX-3 het gelei tot aansienlike variasie in verskeie sellulêre weë, insluitend aminosuur-, koolhidraat- en vetsuur-metabolisme en oksidatiewe stres. Hierdie en ander verskille dui op moontlike versteurde poli-amien metabolisme in die afwesigheid van ESX-3. Hoewel geen ESX-4 proteïenkomponente opgespoor is in wilde-tipe M. smegmatis nie, vertoon die ESX-4 uitslaanmutant aansienlike proteomiese variasie. Laer vlakke van ESX-3 proteïne dui daarop dat ESX-4 die uitdrukking van ESX-3 beinvloed. Baie van die proteomiese variasie kan geassosieer word met verlaagde ESX-3 uitdrukking, maar ander variasie mag ESX-4 koppel met seldeling en molibdeen metabolisme. Sekretomiese analises van wilde-tipe en ESX uitslaanmutant M. smegmatis stamme is gebruik om nuwe substrate van die M. smegmatis ESX sekresiesisteme te identifiseer. Geen prototipe ESX substrate is geïdentifiseer in die kultuurfiltraat, maar 10 moontlike substrate van die ESX-1, -3 en -4 sekresiesisteme, met die algemene ESX sekresiesein, YxxxD/E, is geïdentifiseer. Die funksies van sommige van hierdie proteïene korreleer met die funksies geïdentifiseer in die proteomiese en metabolomiese analises. Hierdie studie stel die grondslag vir toekomstige werk in die begrip van die funksionele rol en uitdrukkingspatrone van die ESX sekresiesisteme en in die gebruik van globale proteomiese en metabolomiese analises om sellulêre veranderinge in reaksie op spesifieke seine of genomiese veranderinge te verstaan. / The National Research Foundation / German Academic Exchange Service (DAAD), / The Harry Crossley Foundation / The Ernst and Ethel Erikson Trust / Stellenbosch University

Le but de cette thèse est d’expliquer la délinquance prolifique de certains délinquants. Nous avançons la thèse que la délinquance prolifique s’explique par la formation plus fréquente de situations criminogènes. Ces situations réfèrent au moment où un délinquant entre en interaction avec une opportunité criminelle dans un contexte favorable au crime. Plus exactement, il s’agit du moment où le délinquant fait face à cette opportunité, mais où le crime n’a pas encore été commis. La formation de situations criminogènes est facilitée par l’interaction et l’interdépendance de trois éléments : la propension à la délinquance de la personne, son entourage criminalisé et son style de vie. Ainsi, la délinquance prolifique ne pourrait être expliquée adéquatement sans tenir compte de l’interaction entre le risque individuel et le risque contextuel. L’objectif général de la présente thèse est de faire la démonstration de l’importance d’une modélisation interactionnelle entre le risque individuel et le risque contextuel afin d’expliquer la délinquance plus prolifique de certains contrevenants. Pour ce faire, 155 contrevenants placés sous la responsabilité de deux établissements des Services correctionnels du Québec et de quatre centres jeunesse du Québec ont complété un protocole d’évaluation par questionnaires auto-administrés. Dans un premier temps (chapitre trois), nous avons décrit et comparé la nature de la délinquance autorévélée des contrevenants de notre échantillon. Ce premier chapitre de résultats a permis de mettre en valeur le fait que ce bassin de contrevenants est similaire à d’autres échantillons de délinquants en ce qui a trait à la nature de leur délinquance, plus particulièrement, au volume, à la variété et à la gravité de leurs crimes. En effet, la majorité des participants rapportent un volume faible de crimes contre la personne et contre les biens alors qu’un petit groupe se démarque par un lambda très élevé (13,1 % des délinquants de l’échantillon sont responsables de 60,3% de tous les crimes rapportés). Environ quatre délinquants sur cinq rapportent avoir commis au moins un crime contre la personne et un crime contre les biens. De plus, plus de 50% de ces derniers rapportent dans au moins quatre sous-catégories. Finalement, bien que les délinquants de notre échantillon aient un IGC (indice de gravité de la criminalité) moyen relativement faible (médiane = 77), près de 40% des contrevenants rapportent avoir commis au moins un des deux crimes les plus graves recensés dans cette étude (décharger une arme et vol qualifié). Le second objectif spécifique était d’explorer, au chapitre quatre, l’interaction entre les caractéristiques personnelles, l’entourage et le style de vie des délinquants dans la formation de situations criminogènes. Les personnes ayant une propension à la délinquance plus élevée semblent avoir tendance à être davantage entourées de personnes criminalisées et à avoir un style de vie plus oisif. L’entourage criminalisé semble également influencer le style de vie de ces délinquants. Ainsi, l’interdépendance entre ces trois éléments facilite la formation plus fréquente de situations criminogènes et crée une conjoncture propice à l’émergence de la délinquance prolifique. Le dernier objectif spécifique de la thèse, qui a été couvert dans le chapitre cinq, était d’analyser l’impact de la formation de situations criminogènes sur la nature de la délinquance. Les analyses de régression linéaires multiples et les arbres de régression ont permis de souligner la contribution des caractéristiques personnelles, de l’entourage et du style de vie dans l’explication de la nature de la délinquance. D’un côté, les analyses de régression (modèles additifs) suggèrent que l’ensemble des éléments favorisant la formation de situations criminogènes apporte une contribution unique à l’explication de la délinquance. D’un autre côté, les arbres de régression nous ont permis de mieux comprendre l’interaction entre les éléments dans l’explication de la délinquance prolifique. En effet, un positionnement plus faible sur certains éléments peut être compensé par un positionnement plus élevé sur d’autres. De plus, l’accumulation d’éléments favorisant la formation de situations criminogènes ne se fait pas de façon linéaire. Ces conclusions sont appuyées sur des proportions de variance expliquée plus élevées que celles des régressions linéaires multiples. En conclusion, mettre l’accent que sur un seul élément (la personne et sa propension à la délinquance ou le contexte et ses opportunités) ou leur combinaison de façon simplement additive ne permet pas de rendre justice à la complexité de l’émergence de la délinquance prolifique. En mettant à l’épreuve empiriquement cette idée généralement admise, cette thèse permet donc de souligner l’importance de considérer l’interaction entre le risque individuel et le risque contextuel dans l’explication de la délinquance prolifique. / The purpose of this dissertation is to explain the prolific delinquency of certain offenders. We suggest that prolific delinquency is explained by the formation of a greater number of criminogenic situations. A criminogenic situation makes reference to situations wherein an offender may interact with a criminal opportunity in an environment which is conducive to crime. More precisely, a criminogenic situation is the moment when an offender faces this opportunity, but the crime has not yet been committed. The formation of criminogenic situations facilitated by the interaction and interdependence of three elements: criminal propensity, criminal social environment and deviant lifestyle. Thus, prolific delinquency cannot be adequately explained without accounting for the interaction between individual and contextual risk. The overall objective of this dissertation is to demonstrate the importance of a model based on the interaction between individual and contextual risk to explain the prolific delinquency of some offenders. To accomplish this objective, one hundred and fifty-five offenders, under the responsibility of Services Correctionels du Québec and four Centres Jeunesse, completed an evaluation through self-administered questionnaires. The first objective of this study was to describe and compare, in Chapter Three, the delinquent nature of the offenders in our sample. Our results revealed that our sample of offenders is similar to that of other samples of delinquents; we found this with respect to the nature of their delinquency, and in particular, the volume, diversity and severity of their crimes. Indeed, the majority of the participants reported a small volume of crimes against a person and property. A small group distinguished themselves with a very high lambda (13.1% of offenders in the sample are responsible for 60.3 % of all crimes reported). Additionally, more than four out of five offenders reported having committed at least one crime against a person and one crime against property. Moreover, 50 % reported having committed crimes in at least four subcategories. Finally, although the offenders in our sample have a relatively low IGC (gravity scale) mean (median = 77), nearly 40 % of the offenders reported having committed at least one of the two most serious crimes identified in this study (discharging firearm and robbery). The second specific objective was to explore, in Chapter four, the interaction between personal characteristics, social environment and the lifestyle of offenders which may lead to criminogenic situation. People with a higher propensity to crime tend to be surrounded by other criminalized people and have a more idle lifestyle. The criminalized social environment tends to also influence the lifestyle of these offenders. Thus, the interdependence between these three elements can lead to criminogenic situations and can create a climate conducive to the emergence of prolific delinquency. The last specific objective of this dissertation, covered in Chapter Five, is to analyze the impact of factors leading to situational crime on the nature of the delinquency. Analyses of multiple linear regression and regression trees highlighted the contribution of personal characteristics, social environment and lifestyle in explaining the nature of the crime. On the one hand, regression analyses (additive models) suggest that all the elements leading to situational crime make a unique contribution to the explanation of delinquency. However, on the other hand, regression trees allowed us to better understand the interaction between the elements which underlie prolific delinquency. For example, a lower position on certain items may be offset by a higher position on others. Moreover, the accumulation of risk factors which lead to situational crime does not happen in a linear fashion. These conclusions are supported by the proportions of explained variance which were higher for the regression trees than for the multiple linear regressions. In conclusion, focusing simply on one element (the person and their criminal propensity or the context and its opportunities) or on their combination in a simply additive manner does not represent the reality of criminal phenomenon. This dissertation therefore serves to highlight the importance of considering the interaction between the individual risk and the contextual risk in explaining prolific delinquency.

<p>This dissertation consists of four self-contained essays.</p><p>Essay I (with Cecilia Enström Öst) investigates whether housing allowance affects recipients’ tenure choice in Sweden. A two-stage conditional maxi-mum likelihood probit (2SCMLP) model is applied in a panel data setting to simultaneously control for individual heterogeneity, state dependence and endogeneity. The empirical study is based on administrative data of housing allowance recipients between the years 1994 and 2002. Our results indicate that the housing allowance positively affects recipients’ homeownership propensity in Sweden. </p><p>Essay II investigates whether the Swedish housing allowance system creates dependence on welfare in recipients. Using longitudinal data from Swedish micro database-LINDA, this paper found that there is no evidence of nega-tive duration dependence among the Swedish housing allowance spells. This finding is consistent across different model specifications and various con-trols of the heterogeneity issue. </p><p>Essay III analyzes the impacts of the 1997 reform of Swedish housing al-lowance system on affected recipients’ exit hazards using the DD (differ-ence-in-difference) estimation strategy. This paper found strong evidence that the 1997 reform positively shifted up the conditional exiting probability of the couple with children recipient group, and the estimated magnitude of impact is sizable.</p><p>Essay IV extends the VECM (Vector Error Correction Cointegration Model) and PT (permanent-transitory) variance decomposition framework proposed by Lettau & Ludvigson (2004) to a situation in which total wealth is disag-gregated into housing wealth and financial wealth. The empirical studies are based on the Swedish aggregate quarterly data spanning from 1980q1 to 2004q4. We found strong statistical evidence that the movements of total consumption expenditures, disposable income, housing wealth and financial wealth are tied together. It is also shown that the movements of housing wealth in Sweden contain a large proportion of transitory component. </p>

This dissertation consists of four self-contained essays. Essay I (with Cecilia Enström Öst) investigates whether housing allowance affects recipients’ tenure choice in Sweden. A two-stage conditional maxi-mum likelihood probit (2SCMLP) model is applied in a panel data setting to simultaneously control for individual heterogeneity, state dependence and endogeneity. The empirical study is based on administrative data of housing allowance recipients between the years 1994 and 2002. Our results indicate that the housing allowance positively affects recipients’ homeownership propensity in Sweden. Essay II investigates whether the Swedish housing allowance system creates dependence on welfare in recipients. Using longitudinal data from Swedish micro database-LINDA, this paper found that there is no evidence of nega-tive duration dependence among the Swedish housing allowance spells. This finding is consistent across different model specifications and various con-trols of the heterogeneity issue. Essay III analyzes the impacts of the 1997 reform of Swedish housing al-lowance system on affected recipients’ exit hazards using the DD (differ-ence-in-difference) estimation strategy. This paper found strong evidence that the 1997 reform positively shifted up the conditional exiting probability of the couple with children recipient group, and the estimated magnitude of impact is sizable. Essay IV extends the VECM (Vector Error Correction Cointegration Model) and PT (permanent-transitory) variance decomposition framework proposed by Lettau &amp; Ludvigson (2004) to a situation in which total wealth is disag-gregated into housing wealth and financial wealth. The empirical studies are based on the Swedish aggregate quarterly data spanning from 1980q1 to 2004q4. We found strong statistical evidence that the movements of total consumption expenditures, disposable income, housing wealth and financial wealth are tied together. It is also shown that the movements of housing wealth in Sweden contain a large proportion of transitory component.

Le but de cette thèse est d’expliquer la délinquance prolifique de certains délinquants. Nous avançons la thèse que la délinquance prolifique s’explique par la formation plus fréquente de situations criminogènes. Ces situations réfèrent au moment où un délinquant entre en interaction avec une opportunité criminelle dans un contexte favorable au crime. Plus exactement, il s’agit du moment où le délinquant fait face à cette opportunité, mais où le crime n’a pas encore été commis. La formation de situations criminogènes est facilitée par l’interaction et l’interdépendance de trois éléments : la propension à la délinquance de la personne, son entourage criminalisé et son style de vie. Ainsi, la délinquance prolifique ne pourrait être expliquée adéquatement sans tenir compte de l’interaction entre le risque individuel et le risque contextuel. L’objectif général de la présente thèse est de faire la démonstration de l’importance d’une modélisation interactionnelle entre le risque individuel et le risque contextuel afin d’expliquer la délinquance plus prolifique de certains contrevenants. Pour ce faire, 155 contrevenants placés sous la responsabilité de deux établissements des Services correctionnels du Québec et de quatre centres jeunesse du Québec ont complété un protocole d’évaluation par questionnaires auto-administrés. Dans un premier temps (chapitre trois), nous avons décrit et comparé la nature de la délinquance autorévélée des contrevenants de notre échantillon. Ce premier chapitre de résultats a permis de mettre en valeur le fait que ce bassin de contrevenants est similaire à d’autres échantillons de délinquants en ce qui a trait à la nature de leur délinquance, plus particulièrement, au volume, à la variété et à la gravité de leurs crimes. En effet, la majorité des participants rapportent un volume faible de crimes contre la personne et contre les biens alors qu’un petit groupe se démarque par un lambda très élevé (13,1 % des délinquants de l’échantillon sont responsables de 60,3% de tous les crimes rapportés). Environ quatre délinquants sur cinq rapportent avoir commis au moins un crime contre la personne et un crime contre les biens. De plus, plus de 50% de ces derniers rapportent dans au moins quatre sous-catégories. Finalement, bien que les délinquants de notre échantillon aient un IGC (indice de gravité de la criminalité) moyen relativement faible (médiane = 77), près de 40% des contrevenants rapportent avoir commis au moins un des deux crimes les plus graves recensés dans cette étude (décharger une arme et vol qualifié). Le second objectif spécifique était d’explorer, au chapitre quatre, l’interaction entre les caractéristiques personnelles, l’entourage et le style de vie des délinquants dans la formation de situations criminogènes. Les personnes ayant une propension à la délinquance plus élevée semblent avoir tendance à être davantage entourées de personnes criminalisées et à avoir un style de vie plus oisif. L’entourage criminalisé semble également influencer le style de vie de ces délinquants. Ainsi, l’interdépendance entre ces trois éléments facilite la formation plus fréquente de situations criminogènes et crée une conjoncture propice à l’émergence de la délinquance prolifique. Le dernier objectif spécifique de la thèse, qui a été couvert dans le chapitre cinq, était d’analyser l’impact de la formation de situations criminogènes sur la nature de la délinquance. Les analyses de régression linéaires multiples et les arbres de régression ont permis de souligner la contribution des caractéristiques personnelles, de l’entourage et du style de vie dans l’explication de la nature de la délinquance. D’un côté, les analyses de régression (modèles additifs) suggèrent que l’ensemble des éléments favorisant la formation de situations criminogènes apporte une contribution unique à l’explication de la délinquance. D’un autre côté, les arbres de régression nous ont permis de mieux comprendre l’interaction entre les éléments dans l’explication de la délinquance prolifique. En effet, un positionnement plus faible sur certains éléments peut être compensé par un positionnement plus élevé sur d’autres. De plus, l’accumulation d’éléments favorisant la formation de situations criminogènes ne se fait pas de façon linéaire. Ces conclusions sont appuyées sur des proportions de variance expliquée plus élevées que celles des régressions linéaires multiples. En conclusion, mettre l’accent que sur un seul élément (la personne et sa propension à la délinquance ou le contexte et ses opportunités) ou leur combinaison de façon simplement additive ne permet pas de rendre justice à la complexité de l’émergence de la délinquance prolifique. En mettant à l’épreuve empiriquement cette idée généralement admise, cette thèse permet donc de souligner l’importance de considérer l’interaction entre le risque individuel et le risque contextuel dans l’explication de la délinquance prolifique. / The purpose of this dissertation is to explain the prolific delinquency of certain offenders. We suggest that prolific delinquency is explained by the formation of a greater number of criminogenic situations. A criminogenic situation makes reference to situations wherein an offender may interact with a criminal opportunity in an environment which is conducive to crime. More precisely, a criminogenic situation is the moment when an offender faces this opportunity, but the crime has not yet been committed. The formation of criminogenic situations facilitated by the interaction and interdependence of three elements: criminal propensity, criminal social environment and deviant lifestyle. Thus, prolific delinquency cannot be adequately explained without accounting for the interaction between individual and contextual risk. The overall objective of this dissertation is to demonstrate the importance of a model based on the interaction between individual and contextual risk to explain the prolific delinquency of some offenders. To accomplish this objective, one hundred and fifty-five offenders, under the responsibility of Services Correctionels du Québec and four Centres Jeunesse, completed an evaluation through self-administered questionnaires. The first objective of this study was to describe and compare, in Chapter Three, the delinquent nature of the offenders in our sample. Our results revealed that our sample of offenders is similar to that of other samples of delinquents; we found this with respect to the nature of their delinquency, and in particular, the volume, diversity and severity of their crimes. Indeed, the majority of the participants reported a small volume of crimes against a person and property. A small group distinguished themselves with a very high lambda (13.1% of offenders in the sample are responsible for 60.3 % of all crimes reported). Additionally, more than four out of five offenders reported having committed at least one crime against a person and one crime against property. Moreover, 50 % reported having committed crimes in at least four subcategories. Finally, although the offenders in our sample have a relatively low IGC (gravity scale) mean (median = 77), nearly 40 % of the offenders reported having committed at least one of the two most serious crimes identified in this study (discharging firearm and robbery). The second specific objective was to explore, in Chapter four, the interaction between personal characteristics, social environment and the lifestyle of offenders which may lead to criminogenic situation. People with a higher propensity to crime tend to be surrounded by other criminalized people and have a more idle lifestyle. The criminalized social environment tends to also influence the lifestyle of these offenders. Thus, the interdependence between these three elements can lead to criminogenic situations and can create a climate conducive to the emergence of prolific delinquency. The last specific objective of this dissertation, covered in Chapter Five, is to analyze the impact of factors leading to situational crime on the nature of the delinquency. Analyses of multiple linear regression and regression trees highlighted the contribution of personal characteristics, social environment and lifestyle in explaining the nature of the crime. On the one hand, regression analyses (additive models) suggest that all the elements leading to situational crime make a unique contribution to the explanation of delinquency. However, on the other hand, regression trees allowed us to better understand the interaction between the elements which underlie prolific delinquency. For example, a lower position on certain items may be offset by a higher position on others. Moreover, the accumulation of risk factors which lead to situational crime does not happen in a linear fashion. These conclusions are supported by the proportions of explained variance which were higher for the regression trees than for the multiple linear regressions. In conclusion, focusing simply on one element (the person and their criminal propensity or the context and its opportunities) or on their combination in a simply additive manner does not represent the reality of criminal phenomenon. This dissertation therefore serves to highlight the importance of considering the interaction between the individual risk and the contextual risk in explaining prolific delinquency.

Syfte Studien avser att undersöka ägarstrukturens modererande effekt på sambandet mellan kapitalstruktur och företagsvärde. Utifrån resultatet presenterat i denna studie nås en djupare förståelse för hur företagetsstyrning av ägarstruktur och kapitalstruktur påverkar företagsvärdet. Metod Undersökningen är gjord enligt kvantitativ forskningsmetod. Studien baseras på 263 företag noterade vid main market på Nasdaq Stockholm, sett över åren 2017–2019. Sekundärdata hämtas och analyseras med hjälp av statistiska modeller. Resultat diskuteras med stöd av teoretisk referensram. Slutsats Studiens empiriska resultat visar att ägarstruktur och kapitalstruktur har en signifikant negativ inverkan på företagsvärde. Däremot har ägarstrukturen en icke-signifikant effekt på sambandet mellan kapitalstruktur och företagsvärde. Studien kan därför inte bekräfta att kontrollägare har en väsentlig inverkan på ledningens finansieringsbeslut.  Studiens bidrag Studien visar att ägarstruktur och kapitalstruktur var för sig kan användas som styrmedel för att nå ett högt företagsvärde. Området är outforskat för företag noterade vid main market på Nasdaq Stockholm. Studien ger därför empiriskt underlag för hur dessa företag i praktiken bör styra ägarstruktur och kapitalstruktur för att maximera företagsvärdet. Studien finner dock inget bevis för ägarstrukturens modererande effekt på sambandet mellan kapitalstruktur och företagsvärde. / Purpose The study aims to examine the moderating effect of ownership structure on the relationship between capital structure and firm value. Based on the results presented in this study, a deeper understanding is reached of how companies' governance of ownership structure and capital structure affects firm value. Method The survey is conducted according to a quantitative research method. The study is based on 263 companies listed on the main market on Nasdaq Stockholm over the years 2017-2019. Secondary data is retrieved and analyzed using statistical models. Results are discussed on the basis of a theoretical frame of reference. Conclusion The empirical results of this study show that ownership structure and capital structure have a significant negative effect on firm value. On the other hand, ownership structure has a non-significant effect on the relationship between capital structure and firm value. Therefore, this study can not confirm that control owners have a significant impact on financing decisions made by management. Contribution This study shows that ownership structure and capital structure separately can be used as instruments to achieve high firm value. This is an unexplored area for companies listed on the main market on Nasdaq Stockholm. Therefore, this study provides an empirical basis for how these companies in practice should govern ownership structure and capital structure in order to maximize firm value. However, the study found no evidence of the moderating effect of ownership structure on the relationship between capital structure and firm value.