Umeå, Sweden


Umeå, Sweden
Time filter
Source Type

Sundin K.,UmeaUniversity | Bruce E.,UmeaUniversity | Barremo A.-S.,Vasternorrland County Council
International Journal of Qualitative Studies on Health and Well-being | Year: 2010

Heart failure is a chronic syndrome that has physiological, psychological and social effects. The aim of the study was to illuminate the meanings of support as experienced by elderly women with chronic heart failure. Narrative interviews were conducted with five elderly women with chronic heart failure. A phenomenological hermeneutic method of interpretation was used. The meanings of support were experienced by the women out of two perspectives, that is, when support is present and when there is a lack of support. The findings were revealed in two themes: "Feeling confident means support" and "Feeling abandoned". The women do not wish to be a burden. They want to be independent as much as possible to defend their dignity. An important support to the women is that they are understood and confirmed in their illness. Supportive relations are most valuable, that is, a relationship that supports the women's independence. If there is no supportive relationship, they feel like a burden to others and they feel lonely; this loneliness creates suffering and counteracts wellbeing and health. © 2010 K. Sundin et al.

Holme P.,UmeaUniversity | Holme P.,Sungkyunkwan University | Holme P.,University of Stockholm | Saramaki J.,Aalto University
Physics Reports | Year: 2012

A great variety of systems in nature, society and technology-from the web of sexual contacts to the Internet, from the nervous system to power grids-can be modeled as graphs of vertices coupled by edges. The network structure, describing how the graph is wired, helps us understand, predict and optimize the behavior of dynamical systems. In many cases, however, the edges are not continuously active. As an example, in networks of communication via e-mail, text messages, or phone calls, edges represent sequences of instantaneous or practically instantaneous contacts. In some cases, edges are active for non-negligible periods of time: e.g.,the proximity patterns of inpatients at hospitals can be represented by a graph where an edge between two individuals is on throughout the time they are at the same ward. Like network topology, the temporal structure of edge activations can affect dynamics of systems interacting through the network, from disease contagion on the network of patients to information diffusion over an e-mail network. In this review, we present the emergent field of temporal networks, and discuss methods for analyzing topological and temporal structure and models for elucidating their relation to the behavior of dynamical systems. In the light of traditional network theory, one can see this framework as moving the information of when things happen from the dynamical system on the network, to the network itself. Since fundamental properties, such as the transitivity of edges, do not necessarily hold in temporal networks, many of these methods need to be quite different from those for static networks. The study of temporal networks is very interdisciplinary in nature. Reflecting this, even the object of study has many names-temporal graphs, evolving graphs, time-varying graphs, time-aggregated graphs, time-stamped graphs, dynamic networks, dynamic graphs, dynamical graphs, and so on. This review covers different fields where temporal graphs are considered, but does not attempt to unify related terminology-rather, we want to make papers readable across disciplines. © 2012 Elsevier B.V.

Baskar J.,UmeaUniversity | Lindgren H.,UmeaUniversity
Communications in Computer and Information Science | Year: 2014

This paper proposes a cognitive architecture of an intelligent agent that can have a dialogue with a human agent on health-related topics. This architecture consists of four main components, namely, the Belief Base, the Dialogue Manager, the Task Manager and the Plan Generator. Each component has sub-components that perform a set of tasks for the purpose to enable the agent to be enrolled in a dialogue. In this paper the particular sub-component of the Dialogue Manager, the Dialogue Strategy has been discussed in detail. A notion of scheme is introduced, which functions as a template with variables that are instantiated each time a state is entered. The agent's dialogue strategy is implemented as a combination of the schemes and the state transitions that the agent makes in response to the human's request. We used a combination of finite-state and agent-based dialogue strategies for dialogue management. This combined dialogue strategy enables a multi-topic dialogue between a human and an agent. © Springer International Publishing Switzerland 2014.

Larsen C.,UmeaUniversity | Barzegar H.R.,UmeaUniversity | Nitze F.,UmeaUniversity | Wagberg T.,UmeaUniversity | Edman L.,UmeaUniversity
Nanotechnology | Year: 2012

Flexible and high-aspect-ratio C 60 nanorods are synthesized using a liquid-liquid interfacial precipitation process. As-grown nanorods are shown to exhibit a hexagonal close-packed single-crystal structure, with m-dichlorobenzene solvent molecules incorporated into the crystalline structure in a C 60:m-dichlorobenzene ratio of 3:2. An annealing step at 200°C transforms the nanorods into a solvent-free face-centred-cubic polycrystalline structure. The nanorods are deposited onto field-effect transistor structures using two solvent-based techniques: drop-casting and dip-coating. We find that dip-coating deposition results in a preferred alignment of non-bundled nanorods and a satisfying transistor performance. The latter is quantified by the attainment of an electron mobility of 0.08cm 2V 1s 1 and an on/off ratio of >10 4 for a single-crystal nanorod transistor, fabricated with a solution-based and low-temperature process that is compatible with flexible substrates. © 2012 IOP Publishing Ltd.

Mann I.,UmeaUniversity | Meyer-Vernet N.,University Paris Diderot | Czechowski A.,Polish Academy of Sciences
Physics Reports | Year: 2014

Cosmic dust particles are small solid objects observed in the solar planetary system and in many astronomical objects like the surrounding of stars, the interstellar and even the intergalactic medium. In the solar system the dust is best observed and most often found within the region of the orbits of terrestrial planets where the dust interactions and dynamics are observed directly from spacecraft. Dust is observed in space near Earth and also enters the atmosphere of the Earth where it takes part in physical and chemical processes. Hence space offers a laboratory to study dust-plasma interactions and dust dynamics. A recent example is the observation of nanodust of sizes smaller than 10 nm. We outline the theoretical considerations on which our knowledge of dust electric charges in space plasmas are founded. We discuss the dynamics of the dust particles and show how the small charged particles are accelerated by the solar wind that carries a magnetic field. Finally, as examples for the space observation of cosmic dust interactions, we describe the first detection of fast nanodust in the solar wind near Earth orbit and the first bi-static observations of PMSE, the radar echoes that are observed in the Earth ionosphere in the presence of charged dust. © 2013 Elsevier B.V.

Arlestig L.,UmeaUniversity | Mullazehi M.,Uppsala University | Kokkonen H.,UmeaUniversity | Rocklov J.,UmeaUniversity | And 2 more authors.
Annals of the Rheumatic Diseases | Year: 2012

Background: Rheumatoid factors (RFs) and antibodies against cyclic citrullinated peptides (CCPs) of IgG, IgA and IgM isotype have been shown to precede disease onset by years. Objective: To evaluate serological risk markers in first-degree relatives from multicase families in relation to genetic and environmental risk factors. Methods: 51 multicase families consisting of 163 individuals with rheumatoid arthritis (RA) (mean±SD age, 60±14 years; disease duration 21 years; 71.8% female) and with 157 first-degree relatives unaffected by RA (54±17 years; 59.9% female) were recruited. Isotypes of antibodies against CCPs (IgG, IgA and IgM) and RFs (IgM and IgA) were determined using automated enzyme immunoassays. Cut-off levels were established using receiver operating characteristic curves based on values for 100 unrelated healthy controls. Results: The concentrations and frequencies of all anti-CCP and RF isotypes were significantly increased in first-degree relatives and patients with RA compared with unrelated healthy controls. The relative distribution of IgA and IgM isotypes was higher than IgG in the relatives, whereas the IgG isotype dominated in patients with RA. The patients carried human leucocyte antigenshared epitope (HLA-SE) significantly more often than the relatives (71.4% vs 53.9%, p=0.01), while the frequency of the PTPN22 T variant was similar. HLA-SE, combined with smoking, was significantly related to all combinations of anti-CCP and RF isotypes in patients with RA. No such relationships were found for the first-degree relatives. Conclusions: All anti-CCP and RF isotypes analysed occurred more commonly in unaffected first-degree relatives from multicase families than in controls, but with different isotype distribution from patients with RA.

Panchuk A.,Ukrainian Academy of Sciences | Puu T.,UmeaUniversity
Mathematics and Computers in Simulation | Year: 2015

The aim of the present paper is to investigate an oligopoly market, modelled by using CES production function in combination with the isoelastic demand function. It is supposed that the competitors act not under constant, but eventually decaying returns, and thus, from time to time they need to renew their capital equipment, choosing its optimal amount according to the current market situation. It is shown that the asymptotic trajectories depend essentially on the value of the global capital durability, and are also sensitive to the initial choice of individual inactivity times. In particular, the firms may merge into different groups renewing their capitals simultaneously, which lead to distinct dynamical patterns. It is also studied how the capital wearing out rate influences the system behaviour. © 2013 IMACS.

Wadbro E.,UmeaUniversity | Engstrom C.,Statistics Sweden
Computer Methods in Applied Mechanics and Engineering | Year: 2015

Metallic nano-antennas are devices used to concentrate the energy in light into regions that are much smaller than the wavelength. These structures are currently used to develop new measurement and printing techniques, such as optical microscopy with sub-wavelength resolution, and high-resolution lithography. Here, we analyze and design a nano-antenna in a two-dimensional setting with the source being a planar TE-polarized wave. The design problem is to place silver and air in a pre-specified design region to maximize the electric energy in a small given target region. At optical frequencies silver exhibits extreme dielectric properties, having permittivity with a negative real part. We prove existence and uniqueness of solutions to the governing non-standard Helmholtz equation with absorbing boundary conditions. To solve the design optimization problem, we develop a two-stage procedure. The first stage uses a material distribution parameterization and aims at finding a conceptual design without imposing any a priori information about the number of shapes of components comprising the nano-antenna. The second design stage uses a domain variation approach and aims at finding a precise shape. Both of the above design problems are formulated as non-linear mathematical programming problems that are solved using the method of moving asymptotes. The final designs perform very well and the electric energy in the target region is several orders of magnitude larger than when there is only air in the design region. The performance of the optimized designs is verified with a high order interior penalty method. © 2015 Elsevier B.V.

Futter M.N.,Swedish University of Agricultural Sciences | Klaminder J.,UmeaUniversity | Lucas R.W.,Swedish University of Agricultural Sciences | Laudon H.,Swedish University of Agricultural Sciences | Kohler S.J.,Swedish University of Agricultural Sciences
Environmental Research Letters | Year: 2012

Precise and accurate estimates of silicate mineral weathering rates are crucial when setting policy targets for long-term forest sustainability, critical load calculations and assessing consequences of proposed geo-engineering solutions to climate change. In this paper, we scrutinize 394 individual silicate mineral weathering estimates from 82 sites on three continents. We show that within-site differences of several hundred per cent arise when different methods are used to estimate weathering rates, mainly as a result of uncertainties related to input data rather than conceptually different views of the weathering process. While different methods tend to rank sites congruently from high to low weathering rates, large within-site differences in estimated weathering rate suggest that policies relying on quantitative estimates based upon a single method may have undesirable outcomes. We recommend the use of at least three independent estimates when making management decisions related to silicate mineral weathering rates. © 2012 IOP Publishing Ltd.

Lindgren H.,UmeaUniversity | Eriksson S.,Northern Sweden University Hospital
Studies in Health Technology and Informatics | Year: 2010

The need for improving dementia care has driven the development of the clinical decision support system DMSS (Dementia Management and Support System). A sociotechnical approach to design and development has been applied, with an activity-centered methodology and user participation throughout the process. Prototypes have been developed based on the characteristics of clinical practice and domain knowledge, while clinical practice has been subjected to different efforts for development such as education and organizational change. This paper addresses the lessons learned and role and impact DMSS has had, and is expected to have on the clinical assessment of dementia in different clinics in Sweden, South Korea and Japan. Furthermore, it will be described in what way the development of DMSS and the development of dementia care in these three areas are interlinked. Results indicate that the most important contribution of DMSS at the point of care, is the educational support that DMSS provides, part from the tailored explanatory support related to a patient case. This effect was partly manifested in a change of routines in the encounter with patients. © 2010 The authors and IOS Press. All rights reserved.

Loading UmeaUniversity collaborators
Loading UmeaUniversity collaborators