PhD / Abstract Low back pain is a significant public health problem in many countries of the world being one of the major causes of work absence and disability. Although the outlook for evidence-based management of low back pain has greatly improved over the past decades, many questions remain. Questions related to treatment options, underlying mechanisms of treatment effects and optimal assessment of low back pain have yet to be fully addressed by researchers. The broad aim of this thesis therefore was to contribute to a better understanding of the contemporary management of low back pain by performing studies in these key research areas. Most clinical practice guidelines recommend exercise as an effective treatment option for chronic low back pain. However the evidence for this recommendation comes from trials that are not placebo-controlled and so this may potentially provide biased estimates of the effects of exercise. Therefore a randomised controlled trial testing the effect of motor control exercise versus placebo in patients with chronic low back pain was conducted. Chapters 2 and 3 describe the trial protocol and the report of the trial respectively. A total of 154 patients with chronic low back pain were randomised to receive a motor control exercise program, or placebo (i.e. detuned short-wave therapy and detuned ultrasound therapy). Primary outcomes were pain, function, and the patient’s global impression of recovery measured at 2 months. The exercise intervention improved function and patient’s global impression of recovery, but not pain, at 2 months. The mean effect of exercise on function was 1.1 points (95%CI, 0.3 to 1.8), the mean effect on global impression of recovery was 1.5 points (95%CI, 0.4 to 2.5) and the mean effect on pain was 0.9 points (95%CI, - 0.01 to 1.8), all measured on 11 point scales. Secondary outcomes also favoured motor control exercise. This is the first study ever to demonstrate that motor control exercise is better than placebo for patients with chronic low back pain. Most of the treatment effects were maintained at 6 and 12 months follow-up. These results suggest that this intervention should be considered for patients with chronic low back pain in order to improve disability, function, and global impression of recovery, and to improve pain intensity in the long term, but not in the short term. Rehabilitative ultrasound imaging (RUSI) has been increasingly used by physiotherapists in order to identify impairments in motor control as well as to monitor progress of patients with low back pain. As with any other clinical measure it is important to know how reproducible the RUSI measures are, and although there are some reproducibility studies in the literature, no systematic review on this topic has been conducted. Therefore a systematic review was performed with the objective of assessing the reproducibility studies of RUSI for abdominal wall muscles (Chapter 4). Eligible studies were indentified via searches in CINAHL, EMBASE and MEDLINE with citation tracking via the Web of Science Index. A total of 21 studies were included. Due to heterogeneity of the studies’ designs, pooling the data for a meta-analysis was not possible. RUSI measures of thickness of abdominal wall muscles were found to be reliable. Few studies analysed the reliability for the measurement of thickness changes (reflecting the muscle activity) finding good to poor results. Evidence for the reproducibility of the difference in thickness changes over time (necessary to evaluate improvements in muscle activity with treatment) was not available. A limitation of the existing literature is that studies typically had suboptimal designs and analysis. The current evidence for the reproducibility of RUSI for measuring abdominal muscle activity is mainly based upon studies with suboptimal designs that included mostly healthy subjects, making generalisability to clinical settings uncertain. Some questions about the reproducibility of RUSI measures of abdominal wall muscles are still unanswered; this is mainly due to design issues, such as inadequate statistics, inadequate sampling and lack of control of sources of bias (e.g. blinding and absence of controlling for ordering effects). In addition the clinically important questions about the reproducibility of thickness changes (reflecting the muscle activity) and differences in thickness changes over time (reflecting the improvement or deterioration of muscle activity) have not been adequately investigated. Therefore a reproducibility study that aimed to answer these questions was performed (Chapter 5). Thirty-five patients seeking care for chronic low back pain participated in this study. RUSI measures were taken at baseline and eight weeks post-baseline. Replicate measures of thickness, thickness changes and differences in thickness changes over time were analysed. The reproducibility of static images (thickness) was excellent (ICC2,1 = 0.97, 95%CI = 0.96-0.97, Standard Error of the Measurement (SEM) = 0.04cm, Smallest Detectable Change (SDC) = 0.11cm), the reproducibility of thickness changes was moderate (ICC2,1 = 0.72, 95%CI 0.65-0.76 SEM = 15%, SDC 41%), while the reproducibility of differences in thickness changes over time was poor. Improvements in the test protocol should be undertaken in order to enhance the reproducibility of RUSI measures, especially for differences in thickness chang over time. Self-report outcome measures (questionnaires) are widely used by health care providers for measuring patient’s health status or treatment outcomes. Most of the questionnaires related to low back pain were developed in English and therefore their usefulness in non-English speaking countries is considerably limited. Cross-cultural adaptation and clinimetric testing are possibly the most efficient methods for solving this problem. Although there are many publications on the topic, a simple guide on how to perform a cross-cultural adaptation and clinimetric testing was not available. Therefore a “clinician-friendly” narrative review for Brazilian physical therapists (Chapter 6) was written. This review aimed firstly to explain the concepts and the relevance of cross-cultural adaptation and clinimetrics testing, secondly to summarise the current guidelines on the topic, thirdly to provide advice on how to choose a relevant questionnaire and finally how to evaluate the quality of an adapted questionnaire. Some examples of cross-cultural adaptations and clinimetrics testing of relevant low back pain questionnaires in the Brazilian-Portuguese language were also provided. Although the number of international versions of low back questionnaires is growing, to date it is unclear which questionnaires have been cross-culturally adapted and into which specific language. To answer these questions a systematic review was conducted in order to describe the available cross-cultural adaptations of low back pain self-report outcome measures and the clinimetric testing that has occurred for each adaptation (Chapter 7). Searches were performed in MEDLINE, EMBASE, CINALH and LILACS; these searches were supplemented with information from experts in the field of low back pain from 27 different countries to ensure that the results were comprehensive. Sixty-one adaptations were identified. While there are a large number of low back pain questionnaires available, very few have been adapted into other languages, particularly commonly spoken languages such as Mandarin, Hindi and Portuguese. The quality and comprehensiveness of clinimetric testing varied considerably, with the evaluation of reliability and construct validity most common. Further cross-cultural adaptation and clinimetric studies are clearly needed and special consideration must be given to study designs for clinimetric testing. The final aim of this thesis was to cross-culturally adapt self-report instruments relevant to the management of low back pain in Brazil. This was achieved by two independent studies. The first study (Chapter 8) aimed to cross-culturally adapt the Functional Rating Index (FRI) into Brazilian-Portuguese and to test the clinimetric properties of the FRI and also of an existing Brazilian-Portuguese version of the Roland Morris Disability Questionnaire (RMDQ) which was not fully evaluated in the original study. Both instruments were tested for internal consistency, reliability, construct validity, ceiling and floor effects and internal responsiveness in 140 chronic low back patients presenting for physiotherapy treatment in Brazil. Both instruments were considered reliable and valid for the measurement of disability in Brazilian-Portuguese speakers with low back pain, no ceiling or floor effects were detected, but the internal responsiveness of both instruments was considered small. The second study (Chapter 9) aimed to cross-culturally adapt the Patient-Specific Functional Scale (PSFS) and to perform a head-to-head comparison of the clinimetric properties of the PSFS, RMDQ and FRI. All instruments were tested for internal consistency, reliability, construct validity, ceiling and floor effects, internal and external responsiveness in 99 acute low back patients presenting for physiotherapy treatment in Brazil. In order to fully test the construct validity and external responsiveness, it was necessary to cross-culturally adapt the Pain Numerical Rating Scale and the Global Perceived Effect Scale. The results of this study demonstrate that the Brazilian-Portuguese versions of the RMDQ, FRI and PSFS have similar clinimetric properties to each other and to the original English versions; however the PSFS was the most responsive instrument. The results from the studies in Chapters 8 and 9 will benefit the understanding of low back pain by enabling international comparisons between studies conducted in Brazil and English speaking countries. In addition it will encourage researchers to include Brazilian- Portuguese speakers in their future clinical trials. Overall, the studies included in this thesis have provided an important contribution to the contemporary management of low back pain. Firstly the use of motor control exercise could be considered for patients with chronic low back pain as it produces improvements in global impression of recovery, function, disability and pain. Secondly RUSI measures of abdominal wall muscles in patients with low back pain were considered reproducible for the measurement of muscle activity, but not as an outcome measure to detect improvement/deterioration of muscle activity over the course of treatment. Thirdly just a few high-quality cross-cultural adaptations and clinimetrics testing for self-report outcome measures relevant to the management of low back pain are available, and clearly more studies in this area are needed. Finally the Brazilian-Portuguese versions of the Functional Rating Index, the Roland Morris Disability Questionnaire and the Patient-Specific Functional Scale have acceptable clinimetric properties and could be used in clinical practice as well as in research studies in Brazil.

Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.

<p>Low-Cost Housing Projects is an essential part in the line of developing sustainable solutions for the provision of shelter for ordinary people in the third world. In poor countries severe problems like population growth, uncontrolled urbanisation processes, deforestation and erosion are present as a result of misuse of all different kinds of resources; this is the fact also in Ethiopia. This degree project is a sub-project integrated in a larger research project at Halmstad University concerning Sustainable Low Cost Housing for the Kambaata Region, Ethiopia. The purpose of this sub-project is to plan and design two dwellings as when erected will serve as a demonstration project in Durame the main urban area of the Kambaata region.</p><p>The houses will be constructed from the two suitable low cost building materials; Adobe</p><p>blocks and CSSB (Cement Stabilized Soil Blocks).</p>

A steady state, axial flow thermal conductivity test apparatus was designed and constructed to operate between room temperature and approximately 4 Kelvin, and to be compatible with existing electronic instrumentation and a continuous flow cryostat. The test design included a radiation shield that had its temperature profile matched to that of the sample to minimize radiation heat transfer losses. The cryostat was used to provide the controllable, low temperature test environment in which the test apparatus would operate. A special wiring bundle was constructed to ensure proper connection of the test device to the required electronic instrumentation, which was controlled from a computer by custom written software. Once assembled, the thermal conductivity of a high purity copper sample was measured over the temperature range from 45 to 300 Kelvin and compared to literature recommended values. The test was performed a second time to check repeatability of the measurements over a range of temperature. Next, the thermal conductivity of a high purity niobium sample was measured and compared to literature recommended values. This test was also performed twice. When completed, these tests had demonstrated the accuracy and repeatability of the measurement of thermal conductivity by the test apparatus over the range of temperatures specified and over a range of conductivities. Finally, the thermal conductivity of a sample of the bulk metallic glass Vitreloy 1 was measured over the same temperature range. As far as was known, this was the first time the thermal conductivity of this particular material had been tested below 400 Kelvin. / Graduation date: 2003

This dissertation investigates the constraints which arise when switched-capacitor (SC) delta-sigma modulators are designed for low-voltage operation, targeting also low power dissipation, and proposes methods of improving the performance and optimizing for low power dissipation. This is accomplished by identifying critical elements whose performance can lead to increased power dissipation, as well as the fundamental limitations of available analog circuit techniques. A prototype was designed and fabricated, which reflected these findings, and therefore exhibited good performance and nearly optimum power dissipation. One of the key performance parameters is the dc gain of the amplifier in the first stage; it should be high. This is necessary for high linearity and low quantization noise leakage. In low-voltage operation, it may become impractical to use conventional topologies employing cascoding techniques (e.g., folded-cascode) which provide high gain in one single stage. Rather, cascaded structures have to be used. The disadvantage of the latter is the necessity for frequency compensation which results in increased power dissipation. Hence, another objective of this work is to exploit techniques which compensate for the open-loop gain characteristic of the amplifier (dc gain and nonlinearity), thus permitting the utilization of single-stage low-gain topologies. Predictive correlated double sampling is one of such techniques and is analyzed in detail. / Graduation date: 1998

Graduation date: 1997

Finding an explanation for the rise and persistence of European unemployment has been one of the main research programmes of labour economists during the last decade. In this doctoral thesis, we contribute to this literature by questioning the causes of unemployment persistence in Belgium. To that purpose, we conduct an in-depth econometric analysis of the flows out of unemployment in this country. In Chapters 2 and 3, we study the behaviour of the exit rate out of unemployment over duration and calendar time. In Chapter 3, we investigate whether this behaviour differs according to the place of living and the skill level, as measured by the level of education. Finally, in Chapter 4, we determine to what extent the divergences in the rate of flowing from unemployment between workers with different levels of education can be explained by a skill mismatch phenomenon and/or by a job competition story. By refining the causes of unemployment persistence in Belgium, our doctoral research also contributes to the design of more effective labour market policies.

One of the key challenges in face perception lies in determining the contribution of different cues to face identification. In this study, we focus on the role of color cues. Although color appears to be a salient attribute of faces, past research has suggested that it confers little recognition advantage for identifying people. Here we report experimental results suggesting that color cues do play a role in face recognition and their contribution becomes evident when shape cues are degraded. Under such conditions, recognition performance with color images is significantly better than that with grayscale images. Our experimental results also indicate that the contribution of color may lie not so much in providing diagnostic cues to identity as in aiding low-level image-analysis processes such as segmentation.

Inquiry skills in young low-income children may be an important point of intervention for promoting school readiness and later academic achievement. The current study aimed to investigate and measure the inquiry skills of low-income preschoolers. In a newly-designed, game-based assessment (the Inquiry Game), children were instructed to ask questions to determine a target picture among an array of pictures varying by color and object type. Asking constraint-seeking questions that use color and object type to eliminate multiple pictures is a more efficient strategy (and thus evidence of greater inquiry skills), in comparison to asking about a specific picture. One hundred and sixty Head Start preschoolers’ inquiry skills were assessed using the Inquiry Game at three time points. Data on children’s problem solving, math, language, and literacy skills were also collected to examine concurrent and predictive validity of the measure. Results revealed that asking about one picture at a time was the most popular strategy at all time points; however, children asked more efficient questions in the winter and spring when compared to performance in the fall. Analyses revealed a relationship between inquiry skills and vocabulary, verbal reasoning, and matrix reasoning ability. Results, as well as future directions, are presented and discussed.

Transition edge sensors are the detectors of choice for a wide range of applications; from dark matter search, neutrino search, to cosmic radiation detection from near infrared to millimeter wavelengths. We are developing transition edge sensors using superconducting iridium thin films and we are proposing their use for future dark matter and neutrino search experiments. Our Ir films are deposited using an radio frequency (RF) magnetron sputtering and photolithographic techniques and measured using an adiabatic refrigerator capable of reaching temperatures of a few tens of mK. This thesis presents a detailed description of superconducting iridium thin films from the fabrication process to the characterization of the film properties at room temperature and low temperature. Alternative options for the bias circuit used to read out the TES signals will be discussed, we are proposing the use of RLC resonant circuits and transformers instead of SQUIDS.