Background The point of departure in this thesis is that unemployment is a recognised determinant of health, which may vary between different ages and among men and women. Despite governmental policies to tackle unemployment and ease its effects on health, unemployment continues to bea growing public health problem. Aim The objective of the thesis was to analyse, from a gender perspective, the relationships between ill health and unemployment as well as other unstable labour market positions in the transition from youth to adulthood. The aim of each paper was: I. Does the association between ill health and unemployment differ between young people and adults? II. Is the transition from an unstable labour market position to permanent paid job health-protective? III. Is participation in labour market programmes related to mental health? IV. What is the association between ill health among men and women and how could it be analysed with a relational theory of gender? Methods The longitudinal study was carried out in Luleå - a medium-sized industrial town in the Northern Sweden. The cohort, consisting of all 1083 pupils (506 girls and 577 boys) aged 16 who attended the last year of compulsory school in 1981, was followed up at the ages of 16, 18, 21 and 30. The response rates were high e.g. 96.4% at 14 years follow-up. The cohort was followed with extensive and well-validated questionnaires. Multivariate logistic regression was used in all papers, while propensity score matchingwas used in Paper III. Results Paper I. Health effects of long-term unemployment differed between young people and adults. Long-term unemployment was more related to psychological ill health and smoking in young people than in adults. Paper II. The results indicated that after controlling for gender as well as for an indicator of health-related selection, possible confounders and mediators transition from an unstable labour market position to permanent employment could be health-promoting. Paper III. No association was found between participation in active labour market programmes and psychological symptoms. Due to methodological shortages the results have to be interpreted with caution. Adjustment for either all background selection variables or the propensity score in multivariate logistic regression showed similar associations suggesting that propensity score could be used to adjust for background selection variables. Paper IV. A strong association between unemployment and suboptimal self-rated health among women and high alcohol consumption among men was found and a theory of structural relations was used to discuss the gendered patterns for ill health. Conclusion The thesis indicated gendered patterns of relations between unemployment and the health outcomes, in the transition from youth to adulthood. The policy implications of my thesis are that full employment policies should be promoted to reduce the health inequalities associated with unemployment. / The Northern Swedish Cohort study

Las Bebidas con Aroma a Limón sufren cambios significativos con el paso del tiempo, que son asociados a deterioro por los consumidores. En la presente Tesis Doctoral se identificaron las causas de la inestabilidad de los Aromas de Limón. Para lograr la aparición de los defectos en forma acelerada se prepararon Bebidas con Aroma a Limón y se expusieron a alta temperatura. La identificación del defecto se realizó en primera instancia mediante técnicas de Evaluación Sensorial, conformando un Panel de Evaluadores Expertos, entrenados con Descriptores Sensoriales y una Rueda del Aroma Limón diseñados en este trabajo. Por otra parte se llevaron a cabo análisis de Cromatografía Gaseosa acoplada a Espectroscopía de Masas, para identificar los cambios químicos que experimentan los Aromas de Limón. La comparación de ambas metodologías presentó resultados que permitieron diseñar Aromas de Limón para uso en Bebidas, estables y con un alto nivel de aceptación por los consumidores. / Lemon Beverages experience significant changes over time, which are perceived as deterioration by consumers. This PhD thesis identifies the causes of Lemon Flavours instability. To achieve the quick appearance of the defects, Lemon Flavoured Beverages were prepared and exposed to high temperature. The identification of the defects was first performed by Sensory Evaluation techniques, training an Expert Panel of Evaluators, with tailor made Sensory Descriptors and a Lemon Flavour Wheel. Moreover analytical methods were performed using Gas Chromatography with Mass Spectroscopy, to identify the chemical changes experienced by Lemon Flavours. The comparison of both methodologies showed results that allowed the design Lemon Flavours to use in beverages, stable and with a high level of consumer acceptance.

The procedures and results of experimental and/or theoretical studies of four transient molecules, GeO, WO, BeH, and MgH are reported in the thesis. Two of them, GeO and WO, are diatomic molecules composed of relatively heavy atoms, and the other two are diatomic molecules with hydrogen as one of their component atoms. The GeO species was generated using a high temperature furnace. The rovibrational spectrum of five isotopomers were detected in emission using a Bruker IFS 120 HR Fourier transform spectrometer. Combined-isotopomer Dunham-type molecular constants have been derived for GeO using the DSParFit computer program. Analysis shows that the Born-Oppenheimer approximation is valid, as expected, for a molecule containing heavy atoms. The WO molecule was generated using a microwave discharge cell, and the spectra of electronic transitions of various systems were detected in emission using both the Bruker IFS 120 HR Fourier transform spectrometer at Waterloo and the McMath Pierce One-Meter Fourier transform spectrometer at the National Solar Observatory in Arizona. The ground electronic state has been confirmed to be X³Σ^- based on the analysis of seven 0-0 bands. BeH and MgH are typical molecules with hydrogen as one of their component atoms, and the effects of Born-Oppenheimer breakdown were expected. Both of these molecules have rotational perturbations in their excited electronic states. A 'new' method of data processing was used, i. e. , treating the electronic data as if they were from fluorescence series. Thus the harmful influence of the perturbed upper electronic states on the ground electronic state molecular constants is eliminated. By using the DSParFit computer program, accurate sets of combined-isotopomer Dunham-type molecular constants have been derived for the ground electronic states of the two molecules, and Born-Oppenheimer breakdown correction terms have been obtained.

Rotordynamic instability can be disastrous for the operation of high speed turbomachinery in the industry. Most ??instabilities?? are due to de-stabilizing cross coupled forces from variable fluid dynamic pressure around a rotor component, acting in the direction of the forward whirl and causing subsynchronous orbiting of the rotor. However, all subsynchronous whirling is not unstable and methods to diagnose the potentially unstable kind are critical to the health of the rotor-bearing system. The objective of this thesis is to explore means of diagnosing whether subsynchronous vibrations are benign or have the potential to become unstable. Several methods will be detailed to draw lines of demarcation between the two. Considerable focus of the research has been on subharmonic vibrations induced from non-linear bearing stiffness and the study of vibration signals typical to such cases. An analytical model of a short-rigid rotor with stiffness non-linearity is used for numerical simulations and the results are verified with actual experiments. Orbits filtered at the subsynchronous frequency are shown as a diagnostic tool to indicate benign vibrations as well as ??frequency tracking?? and agreement of the frequency with known eigenvalues. Several test rigs are utilized to practically demonstrate the above conclusions. A remarkable finding has been the possibility of diagnosing instability using the synchronous phase angle. The synchronous phase angle ?? is the angle by which the unbalance vector leads the vibration vector. Experiments have proved that ?? changes appreciably when there is a de-stabilizing cross coupled force acting on the rotor as compared to when there is none. A special technique to calculate the change in ?? with cross-coupling is outlined along with empirical results to exemplify the case. Subsequently, a correlation between the synchronous phase angle and the phase angle measured with most industrial balancing instruments is derived so that the actual measurement of the true phase angle is not a necessity for diagnosis. Requirements of advanced signal analysis techniques have led to the development of an extremely powerful rotordynamic measurement teststand ?? ??LVTRC??. The software was developed in tandem with this thesis project. It is a stand-alone application that can be used for field measurements and analysis by turbomachinery companies.

This thesis deals with high angle of attack behaviour of a generic delta wing model aircraft. A high angle of attack wind tunnel database has been generated for this aircraft and based upon the bifurcation analysis of the data and the results of extensive simulations, it has been shown in the thesis that the post stall behaviour of this aircraft is both unstable and unpredictable. Unpredictability of aircraft behaviour arises from the fact that the aircraft response is oscillatory and divergent; the aircraft state trajectories do not settle down to any stable limit set and very often exceed valid aerodynamic database limits. This unpredictability of behaviour raises a major difficulty in the design of a procedure to recover the aircraft to normal flight regime in case the aircraft stalls and departs accidentally. A new methodology has been presented in this thesis to recover such unstable aircraft. In this methodology, a nonlinear controller is first designed at high angles of attack. This controller is connected by the pilot after the departure of the aircraft and the controller drives the aircraft to a well-defined spin condition. Thus, the controller makes the post stall aircraft behaviour predictable. Then a set of automatic recovery inputs is designed to reduce aircraft rotations and to lower the angle of attack. The present aircraft model is unstable at low angle of attack flight conditions as well and therefore to stabilize the aircraft to a low angle of attack level flight, another controller is designed. The high angle of attack controller is disconnected and the low angle of attack controller is connected automatically during the recovery process. The entire methodology is tested using extensive non-linear six degree-of-freedom simulations and the efficacy of the technique is established. The nonlinear controller that stabilizes the aircraft to a spin condition is designed using feedback linearization. The stability of a closed loop system obtained using feedback linearization is determined by the stability of the zero dynamics of the open loop plant. It has been shown in literature that the eigenvalues of the linearized zero dynamics are the same as the transmission zeros of the linearized plant at the equilibrium point. It is also well known that the location of transmission zeros of a linear system can be changed by the choice of outputs. In this thesis it is shown that if it is possible to reassign the outputs, then the feedback linearization based design for a linear system becomes very similar to a controller design for eigenvalue assignment. This thesis presents a new two-step procedure to obtain a locally stable and optimally robust closed loop system using feedback linearization. In the first step of this procedure optimal locations of the transmission zeros are found and in the second step, optimal outputs are constructed to place the system transmission zeros at these locations. The same outputs can then be used to construct nonlinear feedback for the nonlinear system and the resultant closed loop system is guaranteed to be locally robustly stable. The high angle of attack controller is designed using this procedure and its performance is presented in the thesis. The stabilized spin equilibrium point of the closed loop system is also shown to have a large domain of attraction. Having designed a locally robust stabilizing controller, the thesis addresses the problem of the evaluation of robustness of the stability of the equilibrium point in a nonlinear framework. The thesis presents a general method to construct bounds on the additive perturbations of the system vector field over a large region in the domain of attraction of a stable equilibrium point using Lyapunov functions. If the system perturbations lie within these bounds, the system is guaranteed to be stable. The thesis first proposes a method to numerically construct a Lyapunov function over a large region in the domain of attraction. In this method a sequence of Lyapunov functions are constructed such that each function in the sequence gives a larger estimate of the domain of attraction than the previous one. The seminal idea for this method is obtained from the existing literature and this idea is considerably generalized. Using this method, it is possible to numerically obtain a Lyapunov function value at each point in the domain of attraction, but the Lyapunov function does not have an analytical form. Hence, it is proposed to represent this function using neural networks. The thesis then discusses a new method to construct perturbation bounds. It is shown that the perturbation bounds obtained over a large region in the domain of attraction using a single Lyapunov function is too conservative. Using the concept of sequence of Lyapunov functions, the thesis proposes three methods to obtain the least conservative bounds for an initial local Lyapunov function. These general ideas are then applied to the aircraft example and the bounds on the perturbation of the aerodynamic database are presented.

Diss. (sammanfattning) Umeå : Umeå universitet, 2009. / Härtill 4 uppsatser. Även tryckt utgåva.

An Inverted double pendulum is a combination of two individual pendulums which represents an example of a nonlinear and unstable dynamic system and it is also a good example of a physical system which can exhibit chaotic behavior.This document contains a first analysis of the model and the control of this system. Also presented is the installation of the electrical materials needed to control the system contain instrumenting the motor, current measurement system, motor shaft angle sensor, vision systemand MYRIO which is an embedded hardware device created by National Instruments will be used for data acquisition and control the system

Η αθηροσκλήρυνση είναι μια παθολογική διαδικασία η οποία λαμβάνει χώρα στις μεγάλες αρτηρίες και αποτελεί την υποκείμενη αιτία καρδιαγγειακών συμβαμάτων, εγκεφαλικών επεισοδίων και περιφερικής αρτηριακής νόσου. Η τυπική αθηροσκληρυντική βλάβη αποτελείται από έναν λιπιδικό πυρήνα που καλύπτεται από ινώδες περίβλημα. Ορισμένοι «ευάλωτοι» ασθενείς εμφανίζουν σε μεγάλο ποσοστό τις λεγόμενες «ασταθείς» βλάβες. Αυτές είναι αλλοιώσεις που έχουν την τάση να ρήγνυνται με αποτέλεσμα το σχηματισμό θρόμβου ο οποίος μερικά ή ολικά αποφράσσει την κυκλοφορία. Στην εργασία αυτή μελετώνται η παθοφυσιολογία του φαινομένου και οι παράγοντες που σχετίζονται με την τοπική και συστηματική βιολογία και συμμετέχουν στην αστάθεια και ρήξη της πλάκας. / Atherosclerosis is a pathological process that takes place in the large arteries and constitutes the amenable cause of cardiovascular events, cerebrovascular accidents and peripheral arterial disease. The typical atherosclerotic lesion is constituted by ljpid core that is covered by fibrous cap. Certain \"sensitive\" patients have the predisposition to develop the so - called \"unstable\" lesions. These are alterations that have the tendency to rupture resulting to the formation of clot which occludes the vessel partially or totally. This work studies the pathophysiology of phenomenon and the factors that are related with the local and systematic biology and participate in the instability and rupture of plaque.

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Families lacking adequate housing are increasingly becoming a concern for social services throughout Sweden, challenging a key promise of the social democratic universalist welfare-state. This raises questions about experiences of parenthood under the threat of facing homelessness or while living in temporary and inadequate residence in the Swedish context. A qualitative, explorative interview study among parents without access to the housing market and housed by social services is proposed for this investigation. Interview-analysis using an inductive thematic framework-based model with content-analysis and interpretation suggests that the sample groups perceptions of reality revolves around four main interconnected themes or categories; housing history, mental processes, child-parent relationship, adaptation. These categories each accommodates subthemes such as process, exclusion, depression, repetitive thinking, closeness. Participants housing history is viewed as a process encompassing experiences of inadequacy and their mental processes seems to be dominated by different dimensions and levels of stress, depression and cognitive malfunctioning associated with future plans and living space. The study indicates that these experiences forge a strong and close parent-child relationship and seems to affect participants’ way of viewing their position in society. Observing the results through a theoretical lens concludes that concepts drawn from systems theory, social constructivist ideas such as social representation and positioning theory widens our understanding of how participants situation. Results are also in line with previous qualitative as well as quantitative studies, and can be used to construct concepts and hypothesises regarding identity, class, exclusion and family relations that needs to be tested in further research. Finally, results suggest a careful approach within a social work context towards families living under studied living conditions. It seems pivotal to be aware of how unstable housing can affect mental processes, self-identity and family relationships but keeping in mind that these individual factors are linked to societal structures that lie at the core of homeless or at risk homeless parents’ situation.