Showing papers by "Linköping University published in 2005"

Radical prostatectomy versus watchful waiting in early prostate cancer.

Abstract: BACKGROUND: In 2008, we reported that radical prostatectomy, as compared with watchful waiting, reduces the rate of death from prostate cancer. After an additional 3 years of follow-up, we now repo ...

Computerized Training of Working Memory in Children With ADHD-A Randomized, Controlled Trial

Abstract: Objective Deficits in executive functioning, including working memory (WM) deficits, have been suggested to be important in attention-deficit/hyperactivity disorder (ADHD). During 2002 to 2003, the authors conducted a multicenter, randomized, controlled, double-blind trial to investigate the effect of improving WM by computerized, systematic practice of WM tasks. Method Included in the trial were 53 children with ADHD (9 girls; 15 of 53 inattentive subtype), aged 7 to 12 years, without stimulant medication. The compliance criterion (>20 days of training) was met by 44 subjects, 42 of whom were also evaluated at follow-up 3 months later. Participants were randomly assigned to use either the treatment computer program for training WM or a comparison program. The main outcome measure was the span-board task, a visuospatial WM task that was not part of the training program. Results For the span-board task, there was a significant treatment effect both post-intervention and at follow-up. In addition, there were significant effects for secondary outcome tasks measuring verbal WM, response inhibition, and complex reasoning. Parent ratings showed significant reduction in symptoms of inattention and hyperactivity/impulsivity, both post-intervention and at follow-up. Conclusions This study shows that WM can be improved by training in children with ADHD. This training also improved response inhibition and reasoning and resulted in a reduction of the parent-rated inattentive symptoms of ADHD.

Body size in ecological networks

Abstract: Body size determines a host of species traits that can affect the structure and dynamics of food webs, and other ecological networks, across multiple scales of organization. Measuring body size provides a relatively simple means of encapsulating and condensing a large amount of the biological information embedded within an ecological network. Recently, important advances have been made by incorporating body size into theoretical models that explore food web stability, the patterning of energy fluxes, and responses to perturbations. Because metabolic constraints underpin body-size scaling relationships, metabolic theory offers a potentially useful new framework within which to develop novel models to describe the structure and functioning of ecological networks and to assess the probable consequences of biodiversity change.

Marginalized particle filters for mixed linear/nonlinear state-space models

Abstract: The particle filter offers a general numerical tool to approximate the posterior density function for the state in nonlinear and non-Gaussian filtering problems. While the particle filter is fairly easy to implement and tune, its main drawback is that it is quite computer intensive, with the computational complexity increasing quickly with the state dimension. One remedy to this problem is to marginalize out the states appearing linearly in the dynamics. The result is that one Kalman filter is associated with each particle. The main contribution in this paper is the derivation of the details for the marginalized particle filter for a general nonlinear state-space model. Several important special cases occurring in typical signal processing applications will also be discussed. The marginalized particle filter is applied to an integrated navigation system for aircraft. It is demonstrated that the complete high-dimensional system can be based on a particle filter using marginalization for all but three states. Excellent performance on real flight data is reported.

Fear of re-injury: a hindrance for returning to sports after anterior cruciate ligament reconstruction

Abstract: Unrestricted participation in sports activities and return to the pre-injury level is often reported as an indicator of the success of ACL reconstruction. The athletes’ choice not to return to their pre-injury level may depend on the knee function, but some times, social reasons or psychological hindrances such as fear of re-injury may influence their return to sports. The aim of this study was to investigate whether fear of re-injury due to movement is of significance for returning to previous level of activity in patients who have undergone anterior cruciate ligament reconstruction. The Tampa Scale of Kinesiophobia (TSK), the Knee Injury and Osteoarthritis Outcome Score (KOOS) and some general questions were mailed to 87 patients who underwent ACL reconstruction 3–4 years before the study was conducted. Sixty-two patients (74%) answered the questionnaires (34 men and 28 women). Fifty-three percent of the patients returned to their pre-injury activity level. The patients who did not return to their pre-injury activity level had more fear of re-injury, which was reflected in the TSK. In addition, high fear of re-injury was correlated with low knee-related quality of life. Fear of re-injury must be considered in the rehabilitation and evaluation of the effects of an ACL reconstruction.

The Multiple-Sets Split Feasibility Problem and Its Applications for Inverse Problems

Abstract: The multiple-sets split feasibility problem requires finding a point closest to a family of closed convex sets in one space such that its image under a linear transformation will be closest to another family of closed convex sets in the image space. It can be a model for many inverse problems where constraints are imposed on the solutions in the domain of a linear operator as well as in the operator's range. It generalizes the convex feasibility problem as well as the two-sets split feasibility problem. We propose a projection algorithm that minimizes a proximity function that measures the distance of a point from all sets. The formulation, as well as the algorithm, generalize earlier work on the split feasibility problem. We offer also a generalization to proximity functions with Bregman distances. Application of the method to the inverse problem of intensity-modulated radiation therapy treatment planning is studied in a separate companion paper and is here only described briefly.

Methods for epidemiological study of injuries to professional football players: developing the UEFA model

Abstract: A problem with epidemiological studies of football injuries is the inconsistent manner in which injury is defined and data are collected. Projects have been initiated to study the incidence and causes of injury in football, but there is no uniformly accepted reporting system. In this report, some common pitfalls encountered in the recording of injury are addressed, and practical guidelines for epidemiological studies are provided. An injury reporting system developed for the UEFA Football Safety Project for studies on professional footballers is used as a starting point for a general discussion on injury registration and compared with other existing reporting systems. The recording definition of injury may vary between studies depending on its purpose. A time loss injury definition is practical for all playing levels, and, as a minimum, results on time loss injuries should therefore always be reported separately to allow direct comparisons between studies. There is a need to agree on a uniform sports injury classification system with corresponding diagnostic criteria, as well as standardised return to play criteria after injury.

Guidelines for standardization of radiostereometry (RSA) of implants

Abstract: There is a need for standardization of radiostereometric (RSA) investigations to facilitate comparison of outcome reported from different research groups. In this document, 6 research centers have ...

Internet-based self-help for depression : randomised controlled trial

Abstract: Background Major depression can be treated by means of cognitive – behavioural therapy, but as skilled therapists are in short supply there is a need for self-help approaches. Many individuals with depression use the internet for discussion of symptoms and to share their experience. Aims To investigate the effects of an internet-administered self-help programme including participation in a monitored, web-based discussion group, compared with participation in web-based discussion group only. Method A randomised controlled trial was conducted to compare the effects of internet-based cognitive–behavioural therapy with minimal therapist contact (plus participation in a discussion group) with the effects of participation in a discussion group only. Results Internet-based therapy with minimal therapist contact, combined with activity in a discussion group, resulted in greater reductions of depressive symptoms compared with activity in a discussion group only (waiting-list control group). At 6 months’ follow-up, improvement was maintained to a large extent. Conclusions Internet-delivered cognitive cognitive–behavioural therapy should be pursued further as a complement or treatment alternative for mild-to-moderate depression.

The Innovating Region: Toward a Theory of Knowledge-Based Regional Development

Abstract: This paper sets forth a model of knowledge-based regional development conceived as a set of multi-linear dynamics, based on alternative technological paradigms. Utilizing longitudinal data from a Swedish region, and international comparisons, four stages of development are identified: Inception, Implementation, Consolidation and Renewal. Innovation policy is created 'bottom-up' as an outcome of 'collective entrepreneurship' through collaboration among business, government and academic actors - the 'triple helix'. The key event is the creation of an entrepreneurial university, whether from an existing academic base or a new foundation, which takes initiatives together with government and industry to create a support structure for firm formation and regional growth. The result of these initiatives is a self-sustaining dynamic in which the role of academia and government appears to recede as industrial actors come to the fore and a lineage of firms is created. Nevertheless, as one technological paradigm is exhausted and another one is needed as the base for new economic activity, the role of academia and government comes to the fore again in creating the conditions for the next wave of innovation.

Mechanical properties and machining performance of Ti1−xAlxN-coated cutting tools

Abstract: The mechanical properties and machining performance of Ti 1− x Al x N-coated cutting tools have been investigated. Processing by arc evaporation using cathodes with a range of compositions was performed to obtain coatings with compositions x =0, x =0.25, x =0.33, x =0.50, x =0.66 and x =0.74. As-deposited coatings with x ≤0.66 had metastable cubic structures, whereas x =0.74 yielded two-phase coatings consisting of cubic and hexagonal structures. The as-deposited and isothermally annealed coatings were characterised by nanoindentation, scanning electron microscopy (SEM) and X-ray diffraction (XRD). Cutting tests revealing tool wear mechanisms were also performed. Results show that the Al content, x , promotes a (200) preferred crystallographic orientation and has a large influence on the hardness of as-deposited coatings. The high hardness (∼37 GPa) and texture of the as-deposited Ti 1− x Al x N coatings are retained for annealing temperatures up to 950 °C, which indicates a superior stability of this system compared to TiN and Ti(C,N) coatings. We propose that competing mechanisms are responsible for the effectively constant hardness: softening by residual stress relaxation through lattice defect annihilation is balanced by hardening from formation of a coherent nanocomposite structure of c-TiN and c-AlN domains by spinodal decomposition. This example of secondary-phase transformation (age-) hardening is proposed as a new route for advanced surface engineering, and for the development of future generation hard coatings.

Identification of the Yellow Skin Gene Reveals a Hybrid Origin of the Domestic Chicken

Abstract: Yellow skin is an abundant phenotype among domestic chickens and is caused by a recessive allele (W*Y) that allows deposition of yellow carotenoids in the skin. Here we show that yellow skin is caused by one or more cis-acting and tissue-specific regulatory mutation(s) that inhibit expression of BCDO2 (beta-carotene dioxygenase 2) in skin. Our data imply that carotenoids are taken up from the circulation in both genotypes but are degraded by BCDO2 in skin from animals carrying the white skin allele (W*W). Surprisingly, our results demonstrate that yellow skin does not originate from the red junglefowl (Gallus gallus), the presumed sole wild ancestor of the domestic chicken, but most likely from the closely related grey junglefowl (Gallus sonneratii). This is the first conclusive evidence for a hybrid origin of the domestic chicken, and it has important implications for our views of the domestication process.

Knowledge Communities and Knowledge Collectivities: A Typology of Knowledge Work in Groups*

Abstract: The notion of a 'community-of-practice' (CmP) has become a highly influential way of conceptualizing how decentralized sub-units or groups within firms or organizations operate. CmPs refer to 'tightly knit' groups that have been practising together long enough to develop into a cohesive community with relationships of mutuality and shared understandings. The CmP notion, however, does not fit squarely with how temporary organizations or project organizations operate. Typically these kinds of groups consist of diversely skilled individuals, most of whom have not met before, who have to solve a problem or carry out a pre-specified task within tightly set limits as to time and costs. As a result they tend to become less well-developed groups, operating on a minimal basis of shared knowledge and understandings. Such a group, I suggest, constitutes a 'collectivity-of-practice' (ClP). Mirroring the above distinctions, two ideal-type notions of epistemology are developed. The one inspired from the CmP literature is discussed in a 'knowledge community' terminology, whereas the one associated with ClPs is conceived of as a 'knowledge collectivity'. Finally, I outline some new options for organizational analysis made possible by recognizing these as two different and complementary notions. © Blackwell Publishing Ltd 2005.

UEFA Champions League study: a prospective study of injuries in professional football during the 2001–2002 season

Abstract: Background: No previous study on adult football involving several different countries has investigated the incidence and pattern of injuries at the highest club competitive level. Objective: To investigate the risk exposure, risk of injury, and injury pattern of footballers involved in UEFA Champions League and international matches during a full football season. Method: Eleven top clubs (266 players) in five European countries were followed prospectively throughout the season of 2001–2002. Time-lost injuries and individual exposure times were recorded during all club and national team training sessions and matches. Results: A total of 658 injuries were recorded. The mean (SD) injury incidence was 9.4 (3.2) injuries per 1000 hours (30.5 (11.0) injuries per 1000 match hours and 5.8 (2.1) injuries per 1000 training hours). The risk of match injury was significantly higher in the English and Dutch teams than in the teams from France, Italy, and Spain (41.8 (3.3) v 24.0 (7.9) injuries per 1000 hours; p = 0.008). Major injuries (absence >4 weeks) constituted 15% of all injuries, and the risk of major injury was also significantly higher among the English and Dutch teams (p = 0.04). National team players had a higher match exposure, with a tendency towards a lower training injury incidence than the rest of the players (p = 0.051). Thigh strain was the most common injury (16%), with posterior strains being significantly more common than anterior ones (67 v 36; p Conclusions: The risk of injury in European professional football is high. The most common injury is the thigh strain typically involving the hamstrings. The results suggest that regional differences may influence injury epidemiology and traumatology, but the factors involved are unclear. National team players have a higher match exposure, but no higher risk of injury than other top level players.

Risk and case characteristics of tuberculosis in rheumatoid arthritis associated with tumor necrosis factor antagonists in Sweden.

Abstract: Objective. Because treatment with tumor necrosis factor (TNF) antagonists may increase the risk of tuberculosis (TB), and because knowledge of the risk of TB in rheumatoid arthritis (RA) not treated with biologics is scarce and of uncertain generalizability to low-risk populations, this study sought to determine the risk of TB among Swedish patients with RA. Methods. Using data from Swedish nationwide and population-based registers and data from an ongoing monitoring program of TNF antagonists, the relative risks of TB in patients with RA (versus the general population) and of TB associated with TNF antagonists (versus RA patients not treated with biologics) were determined by comparing the incidence of hospitalization for TB in 3 RA cohorts and 2 general population cohorts from 1999 to 2001. We also reviewed the characteristics of all reported cases of TB in RA patients treated with TNF antagonists in Sweden and calculated the incidence of TB per type of TNF antagonist between 1999 and 2004. Results. During 1999-2001, RA patients who were not treated with TNF antagonists were at increased risk of TB versus the general population (relative risk 2.0, 95% confidence interval [95% CI] 1.2-3.4). RA patients treated with TNF antagonists had a 4-fold increased risk of TB (relative risk 4.0, 95% CI 1.3-12) versus RA patients not treated with TNF antagonists. The reported TB cases during 1999-2004 in RA patients exposed to TNF antagonists (9 infliximab, 4 etanercept, 2 both) were predominantly pulmonary. TB occurred up to 3 years following the start of treatment. Conclusion. Irrespective of whether TNF antagonists are administered, Swedish patients with RA are at increased risk of TB. During 1999-2001, TNF antagonists were associated with an increased risk of TB, up to 4-fold in magnitude. This increased risk may persist over time during treatment and is related to both infliximab and etanercept.

Ecosystem subsidies: terrestrial support of aquatic food webs from 13c addition to contrasting lakes

Abstract: Whole-lake additions of dissolved inorganic C-13 were used to measure allochthony (the terrestrial contribution of organic carbon to aquatic consumers) in two unproductive lakes (Paul and Peter Lakes in 2001), a nutrient-enriched lake (Peter Lake in 2002), and a dystrophic lake (Tuesday Lake in 2002). Three kinds of dynamic models were used to estimate allochthony: a process-rich, dual-isotope flow model based on mass balances of two carbon isotopes in 12 carbon pools; simple univariate time-series models driven by observed time courses of delta(13)CO(2); and multivariate autoregression models that combined information from time series of delta(13)C in several interacting carbon pools. All three models gave similar estimates of allochthony. In the three experiments without nutrient enrichment, flows of terrestrial carbon to dissolved and particulate organic carbon, zooplankton, Chaoborus, and fishes were substantial. For example, terrestrial sources accounted for more than half the carbon flow to juvenile and adult largemouth bass, pumpkinseed sunfish, golden shiners, brook sticklebacks, and fathead minnows in the unenriched experiments. Allochthony was highest in the dystrophic lake and lowest in the nutrient-enriched lake. Nutrient enrichment of Peter Lake decreased allochthony of zooplankton from 0.34-0.48 to 0-0.12, and of fishes from 0.51-0.80 to 0.25-0.55. These experiments show that lake ecosystem carbon cycles, including carbon flows to consumers, are heavily subsidized by organic carbon from the surrounding landscape.

The innovating region: toward a theory of knowledge‐based regional development

Abstract: This paper sets forth a model of knowledge-based regional development conceived as a set of multi-linear dynamics, based on alternative technological paradigms. Utilizing longitudinal data from a Swedish region, and international comparisons, four stages of development are identified: Inception, Implementation, Consolidation and Renewal. Innovation policy is created ‘bottom-up’ as an outcome of ‘collective entrepreneurship’ through collaboration among business, government and academic actors – the ‘triple helix’. The key event is the creation of an entrepreneurial university, whether from an existing academic base or a new foundation, which takes initiatives together with government and industry to create a support structure for firm formation and regional growth. The result of these initiatives is a self-sustaining dynamic in which the role of academia and government appears to recede as industrial actors come to the fore and a lineage of firms is created. Nevertheless, as one technological paradigm is exhausted and another one is needed as the base for new economic activity, the role of academia and government comes to the fore again in creating the conditions for the next wave of innovation.

Soil CN ratio as a scalar parameter to predict nitrous oxide emissions

Abstract: Forested histosols have been found in some cases to be major, and in other cases minor, sources of the greenhouse gas nitrous oxide (N2O). In order to estimate the total national or global emission ...

Face to Face Collaborative AR on Mobile Phones

Abstract: Mobile phones are an ideal platform for augmented reality. In this paper we describe how they also can be used to support face to face collaborative AR applications. We have created a custom port of the ARToolKit library to the Symbian mobile phone operating system and then developed a sample collaborative AR game based on this. We describe the game in detail and user feedback from people who have played it. We also provide general design guidelines that could be useful for others who are developing mobile phone collaborative AR applications.

Immunology of Preeclampsia

Abstract: Preeclampsia is a placenta-dependent disorder with both local and systemic anomalies with neonatal and maternal morbidity. It is manifested late in pregnancy, but the onset is during early stages of

The crucial role of patient education in heart failure

Abstract: Background: Deterioration of heart failure causes and complicates many hospital admissions in people aged over 65 years. Frequent readmissions cause an immense burden on the individual, the family ...

Autophagy in cardiac myocyte homeostasis, aging, and pathology

Abstract: Autophagy, an intralysosomal degradation of cells' own constituents that includes macro-, micro-, and chaperone-mediated autophagy, plays an important role in the renewal of cardiac myocytes. This cell type is represented by long-lived postmitotic cells with very poor (if any) replacement through differentiation of stem cells. Macroautophagy, the most universal form of autophagy, is responsible for the degradation of various macromolecules and organelles including mitochondria and is activated in response to stress, promoting cell survival. This process is also involved in programmed cell death when injury is irreversible. Even under normal conditions, autophagy is somewhat imperfect, underlying gradual accumulation of defective mitochondria and lipofuscin granules within aging cardiac myocytes. Autophagy is involved in the most important cardiac pathologies including myocardial hypertrophy, cardiomyopathies, and ischemic heart disease, a fact that has led to increasing attention to this process.

Polymer solar cells based on a low-bandgap fluorene copolymer and a fullerene derivative with photocurrent extended to 850 nm

Abstract: Polymer solar cells were fabricated from a low band-gap alternating polyfluorene copolymer, APFO-Green2, combined with [6,6]-phenyl-C61-butyric acid Me ester (PCBM), from org. solns. External quantum efficiencies of the solar cells show an onset at 850 nm and a peak of >10% located at 650 nm, which corresponds to the extended absorption spectrum of the polymer. A photocurrent of 3.0 mA/cm2, photovoltage of 0.78 V, and power conversion efficiency of 0.9% were obtained with solar cells based on this new low-bandgap polymer under an illumination of AM 1.5 (1000 W/m2) from a solar simulator. [on SciFinder (R)]