We aim to develop an implantable, optical neural imaging device by fabricating lasers and photodiodes onto a gallium arsenide substrate. Some studies suggest that lasers exhibit higher noise than light emitting diodes (LEDs) due to coherence effects – my studies aim to quantify this noise and to guide device development. To this end, I developed a model of a fluorescent imaging device which agreed with experiment. Noise analysis performed in phantom showed that laser sources exhibit temporal and spatial noise up to 10x higher than LED sources, and in vivo noise analysis also demonstrated this trend. I studied a neural injury model called cortical spreading depression in vitro in mouse brain slices and in vivo in the rat brain using laser and LED sources. Signal magnitudes in vitro are on the order of 10% and in vivo results are inconclusive. Future work will aim to reduce coherence related noise.

A stochastic leaky integrate-and-fire neuron model was implemented in this study to simulate the spiking activity of the electrosensory "P-unit" receptor neurons of the weakly electric fish Apteronotus leptorhynchus. In the context of sensory coding, these cells have been previously shown to respond in experiment to natural random narrowband signals with either a linear or nonlinear coding scheme, depending on the intrinsic firing rate of the cell in the absence of external stimulation. It was hypothesised in this study that this duality is due to the relation of the stimulus to the neuron's excitation threshold. This hypothesis was validated with the model by lowering the threshold of the neuron or increasing its intrinsic noise, or randomness, either of which made the relation between firing rate and input strength more linear. Furthermore, synchronous P-unit firing to a common input also plays a role in decoding the stimulus at deeper levels of the neural pathways. Synchronisation and desynchronisation between multiple model responses for different types of natural communication signals were shown to agree with experimental observations. A novel result of resonance-induced synchrony enhancement of P-units to certain communication frequencies was also found.

In laser materials processing, the direct measurement and characterization of material and process depth is traditionally a diffcult task. This is particularly difficult when such information needs to be obtained in real-time for feedback and dynamic analysis applications. This thesis outlines a novel method and apparatus for real-time depth measurement during laser processes such as welding, drilling, cutting and ablation called inline coherent imaging (ICI). The approach borrows the coherent imaging ideas from the primarily medical field of optical coherence tomography and adapts them to the new application. Without requirements for flawless image quality and limitations on sample exposure the design is free to emphasize speed in acquisition and processing. Furthermore, the imaging optics are specialized for compatibility with off-the-shelf beam delivery systems. Several generations of the imaging technique and relevant design equations are described and shown and realized. Also described is the design and construction of two laser processing stations used for testing ICI in macro- and micro-processing applications. A variety of applications for ICI in the understanding of percussion drilling and welding of metals and other industrial materials are discussed. The imaging technique is further extended to provide manual and fully automatic closed-loop control of drilling and ablation processes in industrial materials. Finally, some important applications of ICI in the processing of bone in both open and closed-loop configurations are demonstrated. / Thesis (Ph.D, Physics, Engineering Physics and Astronomy) -- Queen's University, 2012-11-04 15:34:14.379

Bakgrund: Kvinnor har högre sjukfrånvaro än män och inom undersköterskeyrket, som är kvinnodominerat, märks detta tydligare. Det finns därmed anledning att uppmärksamma och kartlägga vad som upplevs främja kvinnors arbetsnärvaro och arbetsförmåga i detta yrke. Syfte: Syftet med studien var att utforska äldre kvinnliga undersköterskors upplevelser av betydelse för bibehållen arbetsförmåga inom kommunal äldreomsorg. Metod: Studien genomfördes som en beskrivande kvalitativ intervjustudie med kvalitativ manifest innehålls-analys. Sex friska undersköterskor mellan 55-58 år i kommunal äldreomsorg valdes genom ändamålsenligt urval till semistrukturerade individuella djupintervjuer. Fynd: Under-sköterskorna har förmåga att identifiera och verkställa egna behov. De gör anpassningar, framför allt i privatlivet, och når välbefinnande genom meningsfull tillvaro. Deras beteende kan kopplas till känsla av sammanhang, empowerment och intern känsla av kontroll. Nio kategorier identifierades: Hälsa och fysisk aktivitet, Fysisk arbetsmiljö, Organisation, Samverkan och kommunikation, Medveten anpassning, Arbetstillfredsställelse, Meningsfull tillvaro, Inställning och attityd samt Samhällsnivå. Konklusion: Det är huvudsakligen aspekter av psykosocial karaktär, med inslag av fysisk aktivitet, som upplevs främja arbets-förmåga hos de kvinnliga undersköterskorna. Fynden kan skapa underlag för hälsostödjande arbete där ett beteendemedicinskt synsätt kan vara av värde för förståelsen av hur biopsyko-sociala faktorer samverkar för bibehållen arbetsförmåga. / Background: Women have higher sickness absence rates than men especially within the female dominated profession of assistant nurses. Hence, there is reason to draw attention to and identify what is perceived to promote women’s work attendance and work ability within this profession. Aim: The aim of the study was to explore older female assistant nurses’ experiences of importance for the maintenance of work ability in municipal elderly care. Methods: A descriptive qualitative interview study was conducted and analysed with qualitative manifest content analysis. Six healthy assistant nurses between 55-58 years in municipal elderly care were selected through purposive sampling for semi-structured in-depth interviews. Findings: The assistant nurses are able to identify and implement needs of their own. They adapt, mainly in the private life, and achieve well-being through a meaningful existence. Their behavior can be linked to sence of coherence, empowerment and internal locus of control. Nine categories were identified: Health and physical activity, Physical work environment, Organisation, Collaboration and communication, Intentional adaptions, Work satisfaction, Meaningful existence, Preference and attitude and Societal level. Conclusion: Mainly aspects of psychosocial nature, with elements of physical activity, are perceived to promote work ability by the female assistant nurses. The findings can contribute to form a basis for promotional work where a behavioral medicine approach can be of value in the understanding of how biopsychosocial factors interact for the maintenance of work ability.

Bas van Fraassen argues that inference to the best explanation (IBE) is a probabilistically incoherent rule (1989). Anyone following IBE is open to being Dutch booked. According to one of the most interesting and popular responses to van Fraassen’s argument, van Fraassen misrepresents IBE in probabilistic terms. With the proper probabilistic representation, it is claimed, IBE is not inconsistent with Bayesian rationality constraints. Building on the work of IBE’s proponents, I first propose a minimal account of what makes one explanation better than another. I then argue that, even on this minimal account, the alternative probabilistic model of IBE does not work, and hence fails to successfully respond to van Fraassen’s argument.

Syftet med föreliggande studie var att undersöka hur det kommer sig att vissa personer med ätstörningar väljer att starta en ätstörningsblogg samt hur de upplever sitt bloggande. Respondenterna bestod av fem kvinnor i åldrarna 23-35 år som bloggar om sina ätstörningar. En kvalitativ metod användes där semistrukturerade intervjuer genomfördes över telefon. Resultaten analyserades och tolkades med hjälp av känslan av sammanhang (KASAM) och copingteori. Resultaten visade att anledningarna till att starta en blogg var många, bl.a. kände respondenterna ett behov av en plats att ventilera sina tankar på, och att de genom att blogga om sina erfarenheter såg en möjlighet att hjälpa andra. Bloggen sågs också som ett sätt att kommunicera med sina anhöriga utan att behöva sitta ansikte mot ansikte. Bloggen upplevs medföra ökad social acceptans och den ses som ett positivt stöd i sjukdomen. Resultaten pekar på att bloggande kan ses som ett copingverktyg och att bloggen kan fungera som ett redskap för att begripa, hantera och se mening i ätstörningarna enligt komponenterna i KASAM. / The aim of the following study was to examine why some individuals who have been affected by eating disorders choose to write blogs and how they feel about this experience. The group of respondents consisted of five women aged 23-35, who currently write blogs about their eating disorders. A qualitative method was utilized by means of semi-structured interviews conducted over the telephone and then analyzed using sense of coherence and coping theory. The results showed that the main reasons to start a blog were seeing it as an outlet to vent emotions, a way to help others suffering from eating disorders and a means to communicate about problems without having to do so face to face. Furthermore the blog was viewed as a positive resource to deal with eating disorders and as a way of gaining social support. Blogging can thus be viewed as a coping tool and as a way to increase comprehensibility, manageability and meaningfulness according to the sense of coherence.

Every year a great amount of unaccompanied children flee their homelands without their parents or guardians. This means a journey filled with danger and difficulties. The difficulties don’t only exist during the road ahead but also when the children arrive to the new country. Even if Sweden’s work in receiving refugees is one of the best in the world, it still exist problems. The support work with unaccompanied children is done on different levels in society. The work performed nearest to the individuals takes place at the asylum- permanent residence accommodation where the youth are placed after the decision if they can stay in the country or not. We will in this essay illustrate how the support work with unaccompanied children in the age 13-18 looks like and what effect social support has on the adolescent’s identity development. By visiting two agencies that have asylum- permanent residence accommodation we carried out four interviews with professionals who work on a daily base with the young people. Based on the informant’s narratives and interpretations of the young people’s experiences, we seek to gain knowledge of their situation, both physically and psychologically. We investigated the circumstances behind the feeling of security, how reliance is formed and how social support can help the children’s sense of coherence. We use both crises theory, identity theory and the theory of SOC (sense of coherence) to analyze the informants´ stories. The results of this study show that social support is highly important for a child’s identity development. It is the professional who work on a daily base closely to the children who often symbolize the essence of social support. It’s through their work a safe environment is established and upheld. Identity is shaped through social relationships within groups where solidarity and a mutual confidence exist. We have also acknowledged some deficiencies in the structure of the support work, for example regarding which premises are the young individuals expected to adapt to the Swedish society. The adaption and adjustment has become an obligation for the young individuals rather than for the society.

Syftet med denna uppsats var att undersöka hur en ADHD diagnos sent i livet kan upplevas. Det är en kvalitativ studie utförd genom intervjuer av fyra kvinnor, efter en förutbestämd intervjuguide. Antonovskys teori om KASAM och Lasarus copingstrategier tillämpades på resultaten. Intervjuerna visade att alla kvinnor har haft svårigheter i sin barndom och skola på grund av sin ADHD och deras självkänsla har påverkats negativt. De välkomnade alla diagnosen, som de tyckte gav förklaringar till några av deras problem samt en bättre självkänsla och förståelse av sig själva. Resultaten visade att växa upp med odiagnostiserad ADHD kan påverka självkänslan och leda till psykiska problem, och att utan en diagnos är det svårt att få adekvat hjälp, stöd och förståelse från omgivningen. Vidare visade studien att kvinnornas självkänsla blev bättre efter diagnosen. / The purpose of this study was to investigate how a ADHD diagnosis late in life can be experienced. It is a qualitative study performed by interviewing four women, with a prearranged interview guide. I applied Antonovskys sense of coherence theory and Lazarus coping strategies to the answers received. The interviews indicated that all of the women have had difficulties in their childhood and school because of their ADHD, and their self-esteem has been negatively affected. Indeed, they all welcomed the diagnosis, giving them explanations for some of their problems and a better self-esteem and understanding of themselves.  The results showed that growing up with ADHD but without a proper diagnosis, can affect self-esteem and also cause mental difficulties, and without a diagnosis it appears difficult to get adequate help, support and understanding from the surroundings. Further, it also made clear that the womens self-esteem increased after the diagnosis.

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<p>Developmental biology is a field in which explorations are made to answer how an organism transforms from a single cell to a complex system made up of trillions of highly organized and highly specified cells. This field, however, is not just for discovery, it is crucial for unlocking factors that lead to diseases, defects, or malformations. The one key ingredient that contributes to the success of studies in developmental biology is the technology that is available for use. Optical coherence tomography (OCT) is one such technology. OCT fills a niche between the high resolution of confocal microscopy and deep imaging penetration of ultrasound. Developmental studies of the chicken embryo heart are of great interest. Studies in mature hearts, zebrafish animal models, and to a more limited degree chicken embryos, indicate a relationship between blood flow and development. It is believed that at the earliest stages, when the heart is still a tube, the purpose of blood flow is not for convective transport of oxygen, nutrients and waster, bur rather to induce shear-related gene expressions to induce further development. Yet, to this date, the simple question of "what makes blood flow?" has not been answered. This is mainly due limited availability to adequate imaging and blood flow measurement tools. Earlier work has demonstrated the potential of OCT for use in studying chicken embryo heart development, however quantitative measurement techniques still needed to be developed. In this dissertation I present technological developments I have made towards building an OCT system to study chick embryo heart development. I will describe: 1) a swept-source OCT with extended imaging depth; 2) a spectral domain OCT system for non-invasive small animal imaging; 3) Doppler flow imaging and techniques for quantitative blood flow measurement in living chicken embryos; and 4) application of the OCT system that was developed in the Specific Aims 2-5 to test hypotheses generated by a finite element model which treats the embryonic chick heart tube as a modified peristaltic pump.</p> / Dissertation