• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 284
  • 266
  • 95
  • 49
  • 11
  • 9
  • 8
  • 8
  • 8
  • 6
  • 6
  • 6
  • 6
  • 6
  • 6
  • Tagged with
  • 890
  • 225
  • 147
  • 114
  • 103
  • 90
  • 88
  • 86
  • 85
  • 76
  • 72
  • 63
  • 60
  • 55
  • 52
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
281

Stroke with a focus in the elderly : from a gender and socioeconomic perspective

Löfmark, Ulrika January 2007 (has links)
Stroke is one of the leading causes of death and disability in Sweden and in the Western world. Despite this, stroke with focus on elderly is a field where few studies have been conducted from a gender and socioeconomic perspective. The objectives in this thesis were to analyse from a gender, age and socioeconomic perspective how women were affected by stroke compared with men. The focus was on what it meant for elderly women and men to live with stroke and to explore various gender constructions among men and women. The study also included aspects such as incidence, medical treatment and case fatality after stroke. Both quantitative and qualitative methods were used. During a two-year period (15 October 2000–14 October 2002), uniform information was collected for all cases of first-ever and recurrent (>28 days) stroke occurring in people of all ages living the region of Umeå, admitted to the University Hospital. Five different registers were used to achieve maximum coverage; the Riks-Stroke (RS) register, the Hospital Discharge Register (HDR), the Cause of Death Register, the northern Sweden WHO MONICA study, and one case-finding study in nursing homes and homes for elderly performed for this thesis. For the qualitative study a maximum variation sampling procedure was used to retrieve participants for in-depth interviews in a follow-up study. Nine women and seven men were interviewed about their experiences of treatment and care after suffering a stroke, as well as about their perceptions and experiences of help from others (health care personnel, relatives and home help personnel). The first-ever incidence of stroke was higher among low-educated than high educated men and women. Our study showed that there was an education-related age-dependent difference in stroke incidence, where elderly women had the highest incidence of stroke. The 28-day case fatality was shown to be associated with low educational level in patients above 75 years, after controlling for sex, risk factors and acute care variables. The elderly stroke patients experienced subordination in their contacts with health care personnel and the medical context. The participants used different ways to negotiate in the subordinate position, and some of these negotiations were interpreted as being gendered. We have also shown how the elderly stroke patients minimized their own needs of help, strove for independence and accepted help. The men and the women differed in their perceptions and experiences of help from others. Also, the participants expressed multiple types of needs. The elderly stroke patients’ perceptions and experiences of help from others must be studied in relation to their life circumstances and expectations from society. Further analyses of the patients’ perceptions and experiences of help from others were interpreted as being different examples of constructions of masculinities and femininities. Stroke with a focus on the elderly is a field where few studies have been conducted from a gender and socioeconomic perspective. With further community-based stroke incidence studies including elderly men and women and with the development of appropriately targeted interventions, the burden of stroke in the population could be reduced. More research is needed where both qualitative and quantitative methods are used, as this can provide a richer and perhaps more authentic description of the issue under investigation.
282

A Nationwide Study of Asthma and Allergy in Swedish Preschool Children : with Special Reference to Environment, Daycare, Prevalence, Co-ocurrence and Incidence

Bröms, Kristina January 2010 (has links)
Aim: The aim of this project was to study the age and sex specific occurrence of atopic and non-atopic asthma and other atopic manifestations in a nationwide sample of Swedish pre-school children. Methods: All 70 allergen avoidance day-care centres (AADC) with 84 sections and 140 matched ordinary day-care centres with 440 sections in 62 municipalities across Sweden were sampled. In 2000 the staff at each section responded to a questionnaire on indoor and outdoor environment at the section. In 2002 parents of 5,886 children attending the AADCs and ODCs responded to a postal questionnaire regarding symptoms indicating prevalent asthma, allergic rhinitis, eczema, and food, furred pet and pollen allergy and other data in their children. In 2007, parents of 4255 children responded to an almost identical follow-up questionnaire. Results: The AADCs had far more strict rules than ODCs on furred pets and smoking at home and on perfume use, and the indoor environment was better, owing to better cleaning. The age specific asthma prevalence was curvilinear with a peak at age 3 of 11.4% among boys and 9.8% among girls. In addition the prevalence increased by municipality population density, a proxy for degree of urbanisation. There was a highly significant co-occurrence between all asthma-atopic manifestations, but there was no evidence of ordered sequence of manifestation onset. The asthma incidence was highly dependent on presence or absence of co-occurrence variables. Given the variable mix in the present study population, the annual asthma incidence ranged from 0.6% to 1.2%. Conclusions: AADCs had more strict rules and a better indoor environment than ODCs. The asthma prevalence was affected by age, sex and degree of urbanisation. There was close co-occurrence between all asthma and atopic manifestations but no evidence of ordered sequence of onsets. The annual asthma incidence was strongly dependent of co-occurrence conditions.
283

Spasticity after first-ever stroke

Lundström, Erik January 2009 (has links)
The prevalence of spasticity after first-ever stroke is approximately 20%, but there are no data on the prevalence of disabling spasticity.The reported prevalence of pain after stroke varies between 19% and 74%, whether pain is associated with spasticity is not known. Until now, there is no health economic analysis of patients with spasticity after stroke. Methods: Two groups of patients were studied. Cohort I was a cross-sectional survey. A representative sample of 140 patients was investigated 1 year after their first-ever stroke. Spasticity was defined as ≥ 1 score on the modified Ashworth scale, disabling spasticity was defined as spasticity having such an impact that intervention, e.g. intensive physiotherapy, orthoses or pharmacological treatment, should be offered. Pain was assesed with the Visual Analogue Scale. All direct costs during one year were identified and converted into Purchasing Power Parities US dollar (PPP$). Cohort II was a prospective cohort study. Forty-nine patients were examined at day 2–10, at one month, and at six months after their first-ever stroke. Assessment and definitions were similar as for cohort I. Results: Spasticity occurs within 1 month and disabling spasticity occur within 6 months. After one year, the prevalence of spasticity was 17% and that of  disabling spasticity 4%. Disabling spasticity was more frequent in the upper extremity. There was an independent effect of severe upper extremity paresis (OR 22, CI 3.9–125) and age below 65 years (OR 9.5, CI 1.5–60). The prevalence of stroke-related pain was 21% after one year. Stroke-related pain was associated with paresis (OR 3.1, 95% CI 1.2–7.7), sensory disturbance (OR 3.1, 95% CI 1.1–8.9) and depression (OR 4.1, 95% CI 1.4–13), but not with spasticity as an independent variable. The majority of the direct costs for one year (78%) were associated with hospitalization, whereas 20% was associated with municipality services. Only 1% of all direct costs were related to primary health care and 1% to medication. The mean (median, inter-quartile range) direct cost for stroke patients with spasticity was PPP$ 84 195 (72 116, 53 707) compared to PPP$ 21 842 (12 385, 17 484) for stroke patients without spasticity (P < 0.001).
284

Pathways into ecstasy use: The role of prior cannabis use and ecstasy availability

Zimmermann, Petra, Wittchen, Hans-Ulrich, Waszak, Florian, Nocon, Agnes, Höfler, Michael, Lieb, Roselind 10 April 2013 (has links) (PDF)
Aim: To explore the role of cannabis use for the availability of ecstasy as a potential pathway to subsequent first ecstasy use. Methods: Baseline and 4-year follow-up data from a prospective-longitudinal community study of originally 3021 adolescents and young adults aged 14–24 years at baseline were assessed using the standardized M-CIDI and DSM-IV criteria. Results: Baseline cannabis users reported at follow-up more frequent access to ecstasy than cannabis non-users. Higher cannabis use frequencies were associated with increased ecstasy availability reports. Logistic regression analyses revealed that cannabis use and availability of ecstasy at baseline are predictors for incident ecstasy use during the follow-up period. Testing simultaneously the impact of prior cannabis use and ecstasy availability including potential confounders, the association with cannabis use and later ecstasy use was confirmed (OR = 6.3; 95% CI = 3.6–10.9). However, the association with ecstasy availability was no longer significant (OR = 1.2; 95% CI = 0.3–3.9). Conclusions: Results suggest that cannabis use is a powerful risk factor for subsequent first onset of ecstasy use and this relation cannot be sufficiently explained by availability of ecstasy in the observation period.
285

Aspects of Tax Spillovers: Is There a "Worldwide" Tax Burden?

Bhattacharya, Sandeep 18 August 2010 (has links)
The objective of this dissertation is to develop a model to examine the concept of a “worldwide” tax burden. The notion is that due to differential mobility of factors developed nations may be passing on a share of their tax burden to less developed countries while effectively indulging in a form of tax competition. This is important for many reasons especially since it may affect the distribution of income between countries, and influence the flow of capital. As globalization increases, “the race to the bottom” in taxation (which implies tax-cutting) suggests that these spillovers should be reduced over time. The traditional view of taxation implies that taxation imposes an excess burden and increasing most types of taxes will increase this burden. But for whom does this burden increase? Are developed countries passing on a burden to locations that are less able to shift the burden forward? If this phenomenon of tax spillovers can be quantified, we can examine the extent and nature of shifting of the tax burden. Using a version of the famous general equilibrium model first developed by Prof Harberger in 1962, we analyze the extent of tax spillovers in the presence of a public input in an open economy setting. We model two different taxes, the Capital Income Tax and a Consumption Tax and two different types of expenditure patterns, a government input and a transfer payment. The dissertation answers the following research questions: • Can the extent of tax spillovers be quantified using a general equilibrium model that is not dependent on functional forms? • Does the extent of spillovers depend on the type of tax used? • Does the extent of spillovers depend on the use to which the taxes are put? • What are the policy implications? We find that the tax cutting economy can gain from cutting a distorting tax only when the expenditure pattern is neutral, while imposing a cost to the rest of the world in terms of sources and uses of GDP. When revenues are used to provide productive public goods; neither country gains from tax cuts that lower inputs.
286

Epidemiology and prevention of football injuries

Hägglund, Martin January 2007 (has links)
The aims of this thesis were to study the incidence, severity and pattern of injury in male and female elite football players; to study time trends in injury risk; to identify risk factors for injury; and to test the effectiveness of an intervention programme aimed at preventing re-injury. All studies followed a prospective design using standardised definitions and data collection forms. Individual training and match exposure was registered for all players participating. Time loss injuries were documented by each team’s medical staff. The amount of training increased by 68% between the 1982 and 2001 Swedish top male division seasons, reflecting the shift from semi-professionalism to full professionalism. No difference in injury incidence or injury severity was found between seasons. The injury incidence was 4.6 vs. 5.2/1000 training hours and 20.6 vs. 25.9/1000 match hours. The incidence of severe injury (absence >4 weeks) was 0.8/1000 hours in both seasons. The Swedish and Danish top male divisions were followed during the spring season of 2001. A higher risk for training injury (11.8 vs. 6.0/1000 hours, p<0.01) and severe injury (1.8 vs. 0.7/1000 hours, p=0.002) was observed among the Danish players. Re-injury accounted for 30% and 24% of injuries in Denmark and Sweden respectively. The Swedish top male division was studied over two consecutive seasons, 2001 and 2002, and comparison of training and match injury incidences between seasons showed similar results. Players who were injured in the 2001 season were at greater risk for injury in the following season compared to non-injured players (relative risk 2.7; 95% CI 1.7-4.3). Players with a previous hamstring injury, groin injury and knee joint trauma were two to three times more likely to suffer an identical injury to the same limb in the following season, but no such relationship was found for ankle sprain. Age was not associated with an increased injury risk. The effectiveness of a coach-controlled rehabilitation programme on the rate of re-injury was studied in a randomised controlled trial at amateur male level. In the control group, 23 of 79 injured players suffered a recurrence during the season compared to 10 of 90 players in the intervention group. There was a 75% lower re-injury risk in the intervention group for lower limb injuries (relative risk 0.25; 95% CI 0.11-0.57). The preventive effect was greatest during the first weeks after return to play. Both the male and female Swedish top divisions were followed during the 2005 season. Male elite players had a higher risk for training injury (4.7 vs. 3.8/1000 hours, p<0.05) and match injury (28.1 vs. 16.1/1000 hours, p<0.001) than women. However, no difference was observed in the rate of severe injury (0.7/1000 hours in both groups). The thigh was the most common site of injury in both men and women, while injury to the hip/groin was more frequent in men and to the knee in women. Knee sprain accounted for 31% and 37% of the time lost from training and match play in men and women respectively. / Serienumret i serien Linköping University medical dissertation är fel. Det korrkta numret är 988. The serial number in the series Linköping University medical dissertation is incorrect. The correct number is 988.
287

Clinical and Epidemiological Studies of Wegener´s Granulomatosis

Knight, Ann January 2007 (has links)
Wegener´s granulomatosis (WG) is an unusual, serious, systemic vasculitis with specific clinical findings. The studies in this thesis aim at broadening our understanding of the aetiology and outcome of WG. Patients with WG were identified in the In-patient Register 1975-2001. During this time the incidence increased three-fold, and neither ANCA-related increased awareness, nor diagnostic drift, seem to fully explain this trend, but it is still unclear if a true rise in incidence exists. Anti- neutrophil cytoplasmic antibodies (ANCA) have been presented as highly specific for vasculitis. In a series of consecutive cANCA/PR3-ANCA positive patients, we investigated the positive predictive value for ANCA, and the outcome of patients with a positive cANCA/PR3-ANCA but not vasculitis. These patients have a low future risk of developing vasculitis, possibly indicating that ANCA, in this setting, reflects neutrophil activating properties not specific to vasculitis. By linkage of the WG-cohort, and randomly selected population controls, to the Multi-generation register, we identified all first-degree relatives and spouses of patients and controls, totally encompassing some 2,000 patients and 70,000 relatives. Familial aggregation of WG was the exception, with absolute risks of < 1 per 1000.However, relative risks in first-grade relatives amounted to 1.56 (95% CI 0.35-6.90) such that a moderate familial aggregation cannot be excluded. In the WG-cohort, cancer occurrence and risk was compared to that of the general population. Patients with WG have an overall doubled risk of cancer, with particularly increased risks of bladder-cancer, haematopoietic cancers including lymphomas and squamous skin-cancer. In a case-control study nested within the WG-cohort, treatment with cyclophosphamide was compared among bladder-cancer patients and matched cancer-free controls. Absolute risk of bladder cancer as high as 10% some years after diagnosis were found, and this risk can partly be attributed to cyclophosphamide-treatment, with a dose-response relationship.
288

Theoretical Investigation And Design For X-ray Lasers And Their Lithographic Application

Demir, Pinar 01 July 2008 (has links) (PDF)
Grazing incidence pumping (GRIP) is a scheme to produce x-ray lasers and extreme ultraviolet lithography is a means of lithographic production which requires soft x-rays with a bandwidth of 2% centred at 13,5 nm. In this work firstly a grazing incidence pumping of Ni-like Mo and Ne-like Ti x-ray laser media were simulated by using EHYBRID and a post-processor code coupled to it. The required atomic data were obtained from the Cowan code. Besides, the timing issue needed for amplification purpose in a Ti:Sapphire laser system has been described theoretically. Afterwards, in order to produce soft x-ray lasers for extreme ultraviolet lithographic applications, emission of soft x-rays in the 2% bandwidth centred at 13.5 nm emitted from Sn XII and Sn XIII ions were simulated by using the EHYBRID code for a laser operating at 1064 nm with 1 J of pulse energy and 6 ns of pulse duration. The intensity range that has been investigated is between 1-5 x 1012 W/cm2. Ion fractions of tin ions and line intensities corresponding to different electron temperatures were calculated by using the collisional radiative code NeF.
289

Modèles de regression en présence de compétition

Latouche, Aurélien 20 December 2004 (has links) (PDF)
L'analyse de survie concerne la modélisation des délais de réalisation d'un unique événement. Dans de nombreuses situations cependant, les individus sont soumis à plusieurs causes d'événement exclusives, définissant un cadre dit de risques concurrents ou compétitifs. <br />Ce travail de thèse a porté sur l'étude de modèles de régression dans ce cadre. Deux approches ont été envisagéés, l'une basée sur la fonction de risque instantané cause-spécifique et l'autre sur la <br />fonction de risque instantané associée à la fonction d'incidence cumulée (ou fonction de risque de sous-répartition). Dans les deux cas, nous avons considéré une formulation à risques proportionnels, c'est à dire un modèle de Cox dans le premier cas, et un modèle de Fine & Gray dans le second cas. <br />Dans un premier temps, l'implication d'un choix de modélisation a été étudiée dans le cadre de la planification d'un essai clinique ou d'une étude pronostique. Nous avons alors developpé<br />une formule de calcul du nombre de sujets nécessaire pour le modèle de Fine & Gray. <br />Puis, les conséquences d'un modèle mal spécifié pour la fonction de risque de sous répartition ont été evaluées, en étudiant l'influence sur l'estimation du paramètre de régression dans le modèle de Fine & Gray quand le vrai modèle est un modèle à risques proportionnels pour la fonction de risque cause- <br />spécifique. Nous avons ensuite étudié les implications de l'inclusion de covariables dépendantes du <br />temps dans le modèle de Fine & Gray. <br />Enfin, nous avons présenté une synthèse didactique sur la <br />stratégie d'utilisation des approches présentées dans ce travail de thèse.
290

The Natural History of Human Papillomavirus Related Condyloma In a Multinational Cohort of Men

Anic, Gabriella 01 January 2011 (has links)
Human papillomavirus (HPV) is the most common sexually transmitted infection in the United States, but few studies have examined the progression from HPV infection to disease in men. Genital condyloma are the most common clinical manifestation of HPV infection. Though not associated with mortality, condyloma are a source of emotional distress, and treatment is often painful with a high recurrence rate. The aims of this study were to examine the distribution of HPV types present on the surface of condyloma, estimate the incidence of condyloma overall and after type-specific HPV infections, assess the sociodemographic and sexual behavior factors independently associated with incident condyloma, and examine the concordance between HPV types detected on the surface and in the tissue of condyloma. Participants included 2,487 men from the United States, Brazil, and Mexico who were enrolled in the prospective HPV in Men (HIM) Study and followed every six months for up to four years. At each study visit men completed a computer-assisted-self-administered risk factor questionnaire and samples of healthy penile skin were obtained to test for HPV DNA. A trained clinician examined men for the presence of condyloma and swabbed the surface of lesions to test for HPV DNA. Men were followed for a median of 17.9 months and 112 incident condyloma were identified. Thirty-four external genital lesions were also biopsied to test for HPV within the lesion tissue. PCR was used to test for HPV DNA and Linear Array was used to genotype 13 oncogenic and 24 non-oncogenic HPV types in samples obtained from swabbing the lesion surface. The LiPa assay was used to genotype 20 HPV types in biopsy samples. The Kaplan-Meier method was used to estimate incidence and Cox proportional hazards models were used to examine factors independently associated with incident condyloma. Using biopsy samples as the gold standard, sensitivity and specificity were calculated to examine concordance between HPV types detected on the surface and within the tissue of condyloma. Condyloma incidence was 2.35 per 1,000 person-years. HPV 6 (43.8%), 11 (10.7%), and 16 (9.8%) were the most common types detected on condyloma. The probability of developing condyloma within 24-months of an incident HPV 6/11 infection was 14.6% (95% confidence interval (CI): 7.5-21.1). The median time to condyloma development was 17.1 months (95% CI: 12.4-19.3), with the shortest time to detection observed among men with incident HPV infections with types 6/11 only (6.2 months; 95% CI: 5.6-24.2). Factors associated with condyloma were incident HPV 6/11 infection (hazard ratio (HR) = 12.42; 95% CI: 3.78-40.77), younger age (HR = 0.43; 95% CI: 0.26-0.77; 45-70 vs. 18-30 years), high lifetime number of female partners (HR = 5.69; 95% CI: 1.80-17.97); 21 or greater vs. 0), and sexual behaviors in the previous three months including infrequent condom use (HR = 2.44; 95% CI: 1.16-5.14;

Page generated in 0.0689 seconds