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| 15. |
- El Marghani, Ahmed M., et al.
(författare)
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High MAPK p38 activity and low level of IL-10 in intermittent claudication as opposed to stable angina
- 2010
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Ingår i: International Journal of Angiology. - Torino : Minerva Medica. - 0392-9590 .- 1827-1839. ; 29:4, s. 331-337
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Tidskriftsartikel (refereegranskat)abstract
- AIM:The aim of the present pilot study was to relate the activity of MAPK p38 with the levels of pro- and anti-inflammatory cytokines in a small cohort of patients with either stable angina (N=5) or intermittent claudication (N=5) compared to healthy controls (N=10).METHODS:The activity of MAPK p38 was determined in peripheral blood mononuclear cells, isolated from whole blood by western blot using phospho-specific anti-MAPK p38 antibodies. Cytokine levels of 11 pro- and anti-inflammatory cytokines were determined from the serum using flow cytometry.RESULTS:We found a significant elevation of the MAPK p38 activity in the intermittent claudication group (P=0.0027) compared with the healthy control group whereas the stable angina group showed similar MAPK p38 activity as the healthy control group. The IL-10 level in serum found in the stable angina group was significantly higher compared with both the healthy control group (P=0.0116) and the intermittent claudication group (P=0.0317).CONCLUSION:Our results imply that there is a casual relationship between increased levels of the anti-inflammatory cytokines IL-10 and IL-4 and the activity of the MAPK p38. Possibly has IL-10 a protective role that down-regulates the activity of MAPK p38 and thereby further inflammatory processes in stable angina patients.
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| 16. |
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| 17. |
- Kalia, Lorraine V, et al.
(författare)
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Clinical Correlations With Lewy Body Pathology in LRRK2-Related Parkinson Disease.
- 2015
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Ingår i: JAMA Neurology. - : American Medical Association (AMA). - 2168-6157 .- 2168-6149. ; 72:1, s. 100-105
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Tidskriftsartikel (refereegranskat)abstract
- Mutations in leucine-rich repeat kinase 2 (LRRK2) are the most common cause of genetic Parkinson disease (PD) known to date. The clinical features of manifesting LRRK2 mutation carriers are generally indistinguishable from those of patients with sporadic PD. However, some PD cases associated with LRRK2 mutations lack Lewy bodies (LBs), a neuropathological hallmark of PD. We investigated whether the presence or absence of LBs correlates with different clinical features in LRRK2-related PD.
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| 18. |
- Laine, Romain F., et al.
(författare)
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NanoJ : a high-performance open-source super-resolution microscopy toolbox
- 2019
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Ingår i: Journal of Physics D. - : IOP Publishing. - 0022-3727 .- 1361-6463. ; 52:16
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Forskningsöversikt (refereegranskat)abstract
- Super-resolution microscopy (SRM) has become essential for the study of nanoscale biological processes. This type of imaging often requires the use of specialised image analysis tools to process a large volume of recorded data and extract quantitative information. In recent years, our team has built an open-source image analysis framework for SRM designed to combine high performance and ease of use. We named it NanoJ-a reference to the popular ImageJ software it was developed for. In this paper, we highlight the current capabilities of NanoJ for several essential processing steps: spatio-temporal alignment of raw data (NanoJ-Core), super-resolution image reconstruction (NanoJ-SRRF), image quality assessment (NanoJ-SQUIRREL), structural modelling (NanoJ-VirusMapper) and control of the sample environment (NanoJ-Fluidics). We expect to expand NanoJ in the future through the development of new tools designed to improve quantitative data analysis and measure the reliability of fluorescent microscopy studies.
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| 22. |
- Appelgren, Patrik, et al.
(författare)
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Parametric studies of an electrohydrodynamic plasma actuator for boundary layer flow control
- 2009
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Ingår i: PPC '09. IEEE Pulsed Power Conference, 2009. - : IEEE. - 9781424440658 ; , s. 1069-1074
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Konferensbidrag (refereegranskat)abstract
- An electrohydrodynamic plasma actuator can be used as an aerodynamic flow control device. A plasma actuator is realised as a surface-mounted dielectric barrier discharge (DBD) that transfers directed energy from ions in the discharge to the surrounding air. Parametric studies have been performed in order to investigate the relative efficiency in terms of electrical power into the actuator versus mechanical power in the generated boundary flow. The parametric study includes variations of the applied driving voltage and frequency as well as different electrode and dielectric materials. It is found that, within the range tested, for each value of electrical power into the actuator there exists an optimum driving frequency in terms of boundary layer flow velocity. It is also found that the same trend seems to be true when analyzing electric to mechanical efficiency of the device, i.e. for a given input power there exists an optimum driving frequency that produces the highest efficiency. However, this peak in efficiency of the actuator lies on the edge of the parametric space tested so that further experiments are needed to validate these results.
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| 23. |
- Appelgren, Patrik, et al.
(författare)
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Small helical magnetic flux compression generators : Experiments and analysis
- 2007
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Ingår i: PPPS-2007 - Pulsed Power Plasma Science 2007. - : IEEE. - 1424409144 - 9781424409143 ; , s. 1151-1154
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Konferensbidrag (refereegranskat)abstract
- This paper presents experimental results with helical magnetic flux-compression generators (FCGs). FCGs convert the chemical energy bond in explosives into electric energy. The generator had an initial inductance of 23 μH and was operated into a load of 0.2 μH. The generator is charged with 0.27 kg of high-explosives (PBXN-5). Various types of diagnostics were used to monitor the operation of the generator, including current probes, optical fibres, and piezo gauges. The results are analysed and the expansion of the armature compared with hydrodynamic simulations.
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| 24. |
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| 25. |
- Appelgren, Patrik, et al.
(författare)
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Small Helical Magnetic Flux-Compression Generators : Experiments and Analysis
- 2008
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Ingår i: IEEE Transactions on Plasma Science. - 0093-3813 .- 1939-9375. ; 36:5, s. 2673-2683
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Tidskriftsartikel (refereegranskat)abstract
- In order to gain experience in explosive pulsed power and to provide experimental data for modeling, a small high-explosive-driven helical magnetic flux-compression generator (FCG) was designed at the Swedish Defence Research Agency (FOI). The generator, of which three have been built, has an overall length of 300 mm and a diameter of 70 mm. It could serve as the energy source in a pulse-forming network to generate high power pulses for various loads. This paper presents the design of, and tests with, this helical FCG. The generator had an initial inductance of 23 mu H and was operated into a load of 0.2 mu H. The generator is charged with 0.27 kg of high explosives (PBXN-5). Various types of diagnostics were used to monitor the operation of the generator, including current probes, optical fibers, and piezo gauges. With seed currents of 5.7 and 11.2 kA, final currents of 269 and 436 kA were obtained, corresponding to current amplification factors of 47 and 39. The peak of the current was reached about 30 mu s after the time of crowbar. The two generators showed only small losses in terms of 2 pi-clocking. Using signals from optical fibers, the deflection angle of the armature could be determined to be 10 degrees in good agreement with hydrodynamic simulations of the detonation process and the detonation velocity to be 8.7 km/s in agreement with tabulated value.
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| 26. |
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| 27. |
- Byskov, Jens, et al.
(författare)
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A systems perspective on the importance of global health strategy developments for accomplishing today’s Sustainable Development Goals
- 2019
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Ingår i: Health Policy and Planning. - : Oxford University Press. - 0268-1080 .- 1460-2237. ; 34:9, s. 635-645
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Tidskriftsartikel (refereegranskat)abstract
- Priority setting within health systems has not led to accountable, fair and sustainable solutions to improving population health. Providers, users and other stakeholders each have their own health and service priorities based on selected evidence, own values, expertise and preferences. Based on a historical account, this article analyses if contemporary health systems are appropriate to optimize population health within the framework of cross cutting targets of the Sustainable Development Goals (SDGs). We applied a scoping review approach to identify and review literature of scientific databases and other programmatic web and library-based documents on historical and contemporary health systems policies and strategies at the global level. Early literature supported the 1977 launching of the global target of Health for All by the year 2000. Reviewed literature was used to provide a historical overview of systems components of global health strategies through describing the conceptualizations of health determinants, user involvement and mechanisms of priority setting over time, and analysing the importance of historical developments on barriers and opportunities to accomplish the SDGs. Definitions, scope and application of health systems-associated priority setting fluctuated and main health determinants and user influence on global health systems and priority setting remained limited. In exploring reasons for the identified lack of SDG-associated health systems and priority setting processes, we discuss issues of accountability, vested interests, ethics and democratic legitimacy as conditional for future sustainability of population health. To accomplish the SDGs health systems must engage beyond their own sector boundary. New approaches to Health in All Policies and One Health may be conducive for scaling up more democratic and inclusive priority setting processes based on proper process guidelines from successful pilots. Sustainable development depends on population preferences supported by technical and managerial expertise.
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| 28. |
- Byskov, Jens, et al.
(författare)
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The accountability for reasonableness approach to guide priority setting in health systems within limited resources : findings from action research at district level in Kenya, Tanzania, and Zambia
- 2014
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Ingår i: Health Research Policy and Systems. - : BioMed Central. - 1478-4505. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Background: Priority-setting decisions are based on an important, but not sufficient set of values and thus lead to disagreement on priorities. Accountability for Reasonableness (AFR) is an ethics-based approach to a legitimate and fair priority-setting process that builds upon four conditions: relevance, publicity, appeals, and enforcement, which facilitate agreement on priority-setting decisions and gain support for their implementation. This paper focuses on the assessment of AFR within the project REsponse to ACcountable priority setting for Trust in health systems (REACT). Methods: This intervention study applied an action research methodology to assess implementation of AFR in one district in Kenya, Tanzania, and Zambia, respectively. The assessments focused on selected disease, program, and managerial areas. An implementing action research team of core health team members and supporting researchers was formed to implement, and continually assess and improve the application of the four conditions. Researchers evaluated the intervention using qualitative and quantitative data collection and analysis methods. Results: The values underlying the AFR approach were in all three districts well-aligned with general values expressed by both service providers and community representatives. There was some variation in the interpretations and actual use of the AFR in the decision-making processes in the three districts, and its effect ranged from an increase in awareness of the importance of fairness to a broadened engagement of health team members and other stakeholders in priority setting and other decision-making processes. Conclusions: District stakeholders were able to take greater charge of closing the gap between nationally set planning and the local realities and demands of the served communities within the limited resources at hand. This study thus indicates that the operationalization of the four broadly defined and linked conditions is both possible and seems to be responding to an actual demand. This provides arguments for the continued application and further assessment of the potential of AFR in supporting priority-setting and other decision-making processes in health systems to achieve better agreed and more sustainable health improvements linked to a mutual democratic learning with potential wider implications.
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| 29. |
- Byskov, Jens, et al.
(författare)
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The Need for Global Application of the Accountability for Reasonableness Approach to Support Sustainable Outcomes Comment on "Expanded HTA Enhancing Fairness and Legitimacy"
- 2017
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Ingår i: International Journal of Health Policy and Management. - : Kerman University of Medical Sciences. - 2322-5939. ; 6:2, s. 115-118
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Tidskriftsartikel (refereegranskat)abstract
- The accountability for reasonableness (AFR) concept has been developed and discussed for over two decades. Its interpretation has been studied in several ways partly guided by the specific settings and the researchers involved. This has again influenced the development of the concept, but not led to universal application. The potential use in health technology assessments (HTAs) has recently been identified by Daniels et al as yet another excellent justification for AFR-based process guidance that refers to both qualitative and a broader participatory input for HTA, but it has raised concerns from those who primarily support the consistency and objectivity of more quantitative and reproducible evidence. With reference to studies of AFR-based interventions and the through these repeatedly documented motivation for their consolidation, we argue that it can even be unethical not to take AFR conditions beyond their still mainly formative stage and test their application within routine health systems management for their expected support to more sustainable health improvements. The ever increasing evidence and technical expertise are necessary but at times contradictory and do not in isolation lead to optimally accountable, fair and sustainable solutions. Technical experts, politicians, managers, service providers, community members, and beneficiaries each have their own values, expertise and preferences, to be considered for necessary buy in and sustainability. Legitimacy, accountability and fairness do not come about without an inclusive and agreed process guidance that can reconcile differences of opinion and indeed differences in evidence to arrive at a by all understood, accepted, but not necessarily agreed compromise in a current context -until major premises for the decision change. AFR should be widely adopted in projects and services under close monitoring and frequent reviews.
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| 30. |
- Ehn, A., et al.
(författare)
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Investigations of microwave stimulation of a turbulent low-swirl flame
- 2017
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Ingår i: Proceedings of the Combustion Institute. - : Elsevier BV. - 1540-7489. ; 36:3, s. 4121-4128
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Tidskriftsartikel (refereegranskat)abstract
- Irradiating a flame by microwave radiation is one of several plasma-assisted combustion (PAC) technologies that can be used to modify the combustion chemical kinetics in order to improve flame-stability and to delay lean blow-out. One practical implication is that engines may be able to operate with leaner fuel mixtures and have an improved fuel flexibility capability including biofuels. In addition, this technology may assist in reducing thermoacoustic instabilities that may severely damage the engine and increase emission production. To examine microwave-assisted combustion a combined experimental and computational study of microwave-assisted combustion is performed for a lean, turbulent, swirl-stabilized, stratified flame at atmospheric conditions. The objectives are to demonstrate that the technology increases both the laminar and turbulent flame speeds, and modifies the chemical kinetics, enhancing the flame-stability at lean mixtures. The study combines experimental investigations using hydroxyl (OH) and formaldehyde (CH2O) Planar Laser-Induced Fluorescence (PLIF) and numerical simulations using finite rate chemistry Large Eddy Simulations (LES). The reaction mechanism is based on a methane (CH4)-air skeletal mechanism expanded with sub-mechanisms for ozone, singlet oxygen, chemionization, electron impact dissociation, ionization and attachment. The experimental and computational results show similar trends, and are used to demonstrate and explain some significant aspects of microwave-enhanced combustion. Both simulation and experimental studies are performed close to lean blow off conditions. In the simulations, the flame is gradually subjected to increasing reduced electric field strengths, resulting in a wider flame that stabilizes nearer to the burner nozzle. Experiments are performed at two equivalence ratios, where the leaner case absorbs up to more than 5% of the total flame power. Data from experiments reveal trends similar to simulated results with increased microwave absorption.
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| 33. |
- Fureby, C., et al.
(författare)
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Investigations of microwave stimulation of turbulent flames with implications to gas turbine combustors
- 2017
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Ingår i: AIAA SciTech Forum - 55th AIAA Aerospace Sciences Meeting. - Reston, Virginia : American Institute of Aeronautics and Astronautics. - 9781624104473
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Konferensbidrag (refereegranskat)abstract
- Efficient and clean production of electrical energy and mechanical (shaft) energy for use in industrial and domestic applications, surface- and ground transportation and aero-propulsion is currently of significant general concern. Fossil fuels are mainly used for transportation and aero-propulsion, but also for power generation. Combustion of fossil fuels typically give rise to undesired emissions such as unburned hydrocarbons, carbon dioxide, carbon monoxide, soot and nitrogen oxides. The most widespread approach to minimize these is to apply various lean-burn technologies, and sometimes also dilute the fuel with hydrogen. Although efficient in reducing emissions, lean-burn often results in combustion instabilities and igniteon issues, and thus become challenging itself. Another desired aspect of today’s engines is to increase the fuel flexibility. One possible technique that may be useful for circumventing these issues is plasma-assisted combustion, i.e. to supply a small amount of electric energy to the flame to stimulate the chemical kinetics. Although not new, this approach has not yet been fully explored, partly because of it’s complexity, and partly because of apparent sufficiency. Recently, however, several research studies of this area have emerged. This paper attempts to provide a brief summary of microwave-assisted combustion, in which microwaves are utilized to supply the electrical energy to the flame, and to demonstrate that this method is useful to enhance flame stabilization, delay lean blow-off, and to increase combustion efficiency. The main effect of microwaves (or electrical energy) is to enhance the chemical kinetics, resulting in increased reactivity and laminar and turbulent flame speeds. Here we will demonstrate that this will improve the performance of gas turbine combustors.
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| 34. |
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| 35. |
- Gunell, H., et al.
(författare)
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Numerical experiments on plasmoids entering a transverse magnetic field
- 2009
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Ingår i: Physics of Plasmas. - : AIP Publishing. - 1070-664X .- 1089-7674. ; 16:11
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Tidskriftsartikel (refereegranskat)abstract
- Plasma from the Earth's magnetosheath has previously been observed inside the magnetosphere. Inhomogeneities in the magnetosheath plasma, here called plasmoids, can impact the magnetopause and doing so set up a polarizing field that allows it to penetrate the magnetopause and enter the magnetosphere. A set of simulations of plasmoids with different dimensions is presented in this paper. For plasmoids that are longer than those previously published, waves propagating upstream from the barrier are found. It is also found that the penetration process causes the part of the plasmoid that is upstream of the barrier to rotate. The role of plasmoid width and cross sectional shape in penetration is studied, and for plasmoids that are less than half an ion gyroradius wide, the plasmoid is compressed to obtain a vertically oriented elliptical cross section, regardless of the initial shape. When the initial plasmoid width exceeds the ion gyroradius, the plasmoid still penetrates through a mechanism involving a potential that propagates upstream from the magnetic barrier.
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| 36. |
- Gunell, H., et al.
(författare)
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Simulations of a plasmoid penetrating a magnetic barrier
- 2008
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Ingår i: Plasma Physics and Controlled Fusion. - : IOP Publishing. - 0741-3335 .- 1361-6587. ; 50:7
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Tidskriftsartikel (refereegranskat)abstract
- Plasma structures, here typified by the term 'plasmoids', in the solar wind impacting on the magnetopause, i. e. the boundary between the solar wind and the Earth's magnetosphere, can penetrate this boundary and be injected into the magnetosphere. This can happen either by expulsion of the magnetic field from the structure and subsequent diffusion of the magnetic field into the structure or by the formation of a polarization electric field that lets the plasma structure E x B- drift into the earth's magnetic field. In both cases a collisionless resistivity is required at some stage of the process. While magnetic expulsion requires electromagnetic models for its description, polarization can be modelled electrostatically and both processes can be, and have been, studied in laboratory experiments. We present three-dimensional electrostatic particle-in-cell simulations that reproduce large-amplitude waves, in the lower-hybrid range, that have been observed in laboratory experiments. Lower-hybrid waves have also been seen at the magnetopause of the earth. We consider the implications for spacecraft-based studies of magnetopause penetration, and suggest that the search for penetrating plasma structures should emphasize cases in which the interplanetary magnetic field is oriented northwards, as this configuration is less likely for reconnection. The application of theoretical predictions to the magnetopause environment shows that a plasma structure penetrating via polarization needs to be small, i. e. less than 10-100 km wide for typical parameters, and that wave processes at the magnetopause are needed to create such small structures. A larger structure can penetrate by means of magnetic expulsion.
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| 37. |
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| 38. |
- Hurtig, Per, 1980-, et al.
(författare)
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Early Retransmit for TCP and Stream Control Transmission Protocol (SCTP)
- 2010
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Ingår i: Internet Engineering Task Force. - : Internet Engineering Task Force. - 2070-1721. ; , s. 1-15
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Tidskriftsartikel (refereegranskat)abstract
- This document proposes a new mechanism for TCP and Stream Control Transmission Protocol (SCTP) that can be used to recover lost segments when a connection's congestion window is small. The "Early Retransmit" mechanism allows the transport to reduce, in certain special circumstances, the number of duplicate acknowledgments required to trigger a fast retransmission. This allows the transport to use fast retransmit to recover segment losses that would otherwise require a lengthy retransmission timeout
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| 39. |
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| 40. |
- Kalengayi, Faustine K Nkulu, et al.
(författare)
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'It is a dilemma' : perspectives of nurse practitioners on health screening of newly arrived migrants
- 2015
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Ingår i: Global Health Action. - : Informa UK Limited. - 1654-9716 .- 1654-9880. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Background: Screening newly arrived migrants from countries with high burden of communicable diseases of public health significance is part of the Swedish national strategy against the spread of these diseases. However, little is known about its implementation. Objective: This study aimed at exploring caregivers' experiences in screening newly arrived migrants to generate knowledge that could inform policy and clinical practice. Design: Using an interpretive description framework, we conducted semistructured interviews between November and December 2011 in four Swedish counties, with 15 purposively selected nurses with experience in screening migrants. Data were analyzed using thematic analysis. Results: Participants described a range of challenges including discordant views between migrants and the nurses about medical screening, inconsistencies in rules and practices, and conflicting policies. Participants indicated that sociocultural differences resulted in divergent expectations with migrants viewing the participants as agents of migration authorities. They also expressed concern over being given a new assignment without training and being expected to share responsibilities with staff from other agencies without adequate coordination. Finally, they indicated that existing policies can be confusing and raise ethical issues. All these were compounded by language barriers, making their work environment extremely complex and stressful. Conclusions: These findings illuminate complex challenges that could limit access to, uptake, and delivery of health screening and undermine public health goals, and highlight the need for a multilevel approach. This entails avoiding the conflation of migration with health issues, harmonizing existing policies to make health care services more accessible and acceptable to migrants, and facilitating health professionals' work in promoting public health, improving interagency collaboration and the skills of all staff involved in understanding and effectively responding to migrants' needs, and improving migrants' health literacy through community outreach interventions.
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| 41. |
- Klasson-Heggebø, L., et al.
(författare)
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Graded associations between cardiorespiratory fitness, fatness, and blood pressure in children and adolescents
- 2006
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Ingår i: British Journal of Sports Medicine. - : BMJ. - 0306-3674 .- 1473-0480. ; 40:1, s. 25-29; discussion 25
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE:To measure the graded relation between cardiorespiratory fitness and sum of skinfolds, waist circumference, and blood pressure in children and adolescents participating in the European youth heart study.METHODS:The participants were 4072 children and adolescents (aged 9 and 15) from Denmark, Portugal, Estonia, and Norway. Cardiorespiratory fitness was indirectly determined using a maximal ergometer cycle test. The sum of four skinfolds, waist circumference, and blood pressure were assessed with a standardised protocol. Linear regression analysis was used to test the graded relation between cardiorespiratory fitness and the dependent variables adjusted for pubertal stage, sex, and country.RESULTS:A significant curvilinear graded relation was found between cardiorespiratory fitness and waist circumference and sum of skinfolds (partial r2 for cardiorespiratory fitness was 0.09-0.26 for the different sexes and age groups). Systolic and diastolic blood pressure also showed a curvilinear relation with cardiorespiratory fitness, and fitness explained 2% of the variance in systolic blood pressure. The difference in systolic blood pressure between the least and most fit was 6 mm Hg.CONCLUSION:A curvilinear graded relation was found between cardiorespiratory fitness and waist circumference, sum of skinfolds, and systolic blood pressure. The greatest difference in these health variables was observed between low and moderate fitness levels.
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| 42. |
- Larsson, A., et al.
(författare)
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Skeletal Methane-Air Reaction Mechanism for Large Eddy Simulation of Turbulent Microwave-Assisted Combustion
- 2017
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Ingår i: Energy and Fuels. - : American Chemical Society (ACS). - 0887-0624 .- 1520-5029. ; 31:2, s. 1904-1926
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Tidskriftsartikel (refereegranskat)abstract
- Irradiating a flame via microwave radiation is a plasma-assisted combustion (PAC) technology that can be used to modify the combustion chemical kinetics in order to improve flame stability and to delay lean blow-out. One practical implication is that combustion engines may be able to operate with leaner fuel mixtures and have an improved fuel flexibility capability including biofuels. Furthermore, this technology may assist in reducing thermoacoustic instabilities, which is a phenomenon that may severely damage the engine and increase NOX production. To further understand microwave-assisted combustion, a skeletal kinetic reaction mechanism for methane-air combustion is developed and presented. The mechanism is detailed enough to take into account relevant features, but sufficiently small to be implemented in large eddy simulations (LES) of turbulent combustion. The mechanism consists of a proposed skeletal methane-air reaction mechanism accompanied by subsets for ozone, singlet oxygen, chemionization, and electron impact reactions. The baseline skeletal methane-air mechanism contains 17 species and 42 reactions, and it predicts the ignition delay time, flame temperature, flame speed, major species, and most minor species well, in addition to the extinction strain, compared to the detailed GRI 3.0 reaction mechanism. The amended skeletal reaction mechanism consists of 27 species and 80 reactions and is developed for a reduced electric field E/N below the critical field strength (of ∼125 Td) for the formation of a microwave breakdown plasma. Both laminar and turbulent flame simulation studies are carried out with the proposed skeletal reaction mechanism. The turbulent flame studies consist of propagating planar flames in homogeneous isotropic turbulence in the reaction sheets and the flamelets in eddies regimes, and a turbulent low-swirl flame. A comparison with experimental data is performed for a turbulent low-swirl flame. The results suggest that we can influence both laminar and turbulent flames by nonthermal plasmas, based on microwave irradiation. The laminar flame speed increases more than the turbulent flame speed, but the radical pool created by the microwave irradiation significantly increases the lean blow-out limits of the turbulent flame, thus making it less vulnerable to thermoacoustic combustion oscillations. Apart from the experimental results from low-swirl flame presented here, experimental data for validation of the simulated trends are scarce, and conclusions build largely on simulation results. Analysis of chemical kinetics from simulations of laminar flames and LES on turbulent flames reveal that singlet oxygen molecule is of key importance for the increased reactivity, accompanied by production of radicals such as O and OH.
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| 43. |
- Lindblom, A., et al.
(författare)
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First Trials with a 45 GW Cable-Based Pulsed-Power Generator
- 2009
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Ingår i: Acta Physica Polonica. A. - 0587-4246 .- 1898-794X. ; 115:6, s. 976-977
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Tidskriftsartikel (refereegranskat)abstract
- The output from narrow-band high-power microwave (HPM) sources, such as the virtual cathode oscillator (vircator) and the magnetically insulated line oscillator (MILO), is strongly dependent on the voltage pulse feed. A rectangular, flat-top voltage pulse can be achieved by the use of a transmission line as a pulse-forming unit. The development in high-voltage cable technology has made them useful as parts of high-voltage and high-power generator systems. The generator is designed to deliver a 200 ns voltage pulse of 500 kV into a 10 Omega unmatched load with an electric power of 25 GW. The generator has an impedance of 2 Q. The primary energy storage of the generator consists of a 50 kV, 20 U capacitor bank. The 50 kV is discharged into a transformer that charges a pulse-forming line to 550 kV. When charged, the pulse-forming line is discharged into the load via a spark gap. This paper presents results from initial testing of the generator.
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| 44. |
- Lindblom, Adam, et al.
(författare)
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High-voltage pulsed-power cable generator
- 2009
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Ingår i: IEEE Transactions on Plasma Science. - USA : IEEE. - 0093-3813 .- 1939-9375. ; 37:1, s. 236-242
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Tidskriftsartikel (refereegranskat)abstract
- A cable-based 25-GW pulsed-power generator with output impedance of 2 is presented. It is designed to deliver a 200-ns-long 500-kV pulse into a 10 load. The primary energy storage of the generator consists of a 50-kV 20-kJ capacitor bank. The 50-kV capacitor bank is discharged into a 1 : 12 transformer. The transformer is designed to charge a pulse-forming line (PFL) to 600 kV. When charged, the PFL is discharged into a load via a spark gap. The spark gap is located in a coaxial system containing deionized water together with the cable endings of the PFL and transformer. The electric field at the cable endings is refractively graded by the high permittivity of the surrounding water. The primary and secondary windings consist of high-voltage cables that are interleaved and wound together. The PFL consists of eight 40-m-long 110-kV coaxial cables with both ends connected to the load. Each cable screen is grounded in the middle and connected in parallel. The cables have a characteristic impedance of 30 . The parallel cable setup gives the PFL an impedance of 2 . The total length, height, and width of the pulse generator are 4, 2, and 1.2 m, respectively.
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| 45. |
- Novac, Bucur M., et al.
(författare)
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A 10-GW pulsed power supply for HPM sources
- 2006
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Ingår i: IEEE TRANS PLASMA SCI. ; , s. 1814-1821
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Konferensbidrag (refereegranskat)abstract
- A research activity involving the detailed consideration of novel high-voltage transformers for pulsed-power applications has recently begun at Loughborough University. Although the main goal is the demonstration of a compact and lightweight unit employing magnetic insulation under vacuum conditions, the initial stage of the work is directed toward the development of a conventional air-cored transformer as a main component in a compact power supply for high power microwave sources. In cooperation with the Swedish Defence Research Agency (FOI), the power supply has been tested with a microwave source of the vircator type. The power generator for the system uses a 70-kJ/25-kV capacitor bank and an exploding wire array to generate a 150-kV voltage pulse in the primary circuit of a transformer. A pressurized SF6 spark gap in the secondary circuit sharpens the high-voltage output so that pulses approaching 500 kV and with a rise time well below 100 ns are generated on a 20-Omega high-power resistors With the peak power in excess of 10 GW. Experimental results are presented from final testing of the system, where a reflex triode vircator replaces the 20-Omega resistor. Measurements of the microwave emission using free-field sensors are presented, and comments are made with the microwave emission from the same vircator when powered by a Marx generator at FOI.
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| 46. |
- Nyamhanga, T, et al.
(författare)
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Achievements and challenges of resource allocation for health in a decentralized system in Tanzania : perspectives of national and district level officers
- 2013
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Ingår i: East African Journal of Public Health. - 0856-8960. ; 10:2, s. 417-428
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The goal of this study was to identify the achievements and challenges of a resource allocation process in a decentralized health system in Tanzania as they are perceived by national and district level officers.Methodology: This study was conducted between May 2011 and July 2012 in two districts of Dodoma region: Kongwa and Bahi. Data were collected from 25 key people involved in policy, planning and management aspects for the allocation of financial resources from the central government to local government districts. Thus, the recruitment of the study participants was purposive, as it took account of their positions and experience in health resource allocation and management. The data were collected through conversation in face-to-face in-depth interviews with the officers concerned. The data were analysed manually using qualitative content analysis.Results: The study has identified the achievements and challenges of resource allocation in a decentralized health system of Tanzania. The achievements include: the design and use of a needs-based resource allocation formula; reduced resource allocation inequalities between rural and urban districts; and a wide discretion by the district council to mobilize and utilize health insurance funds and user fees. On the other hand, the challenges are: the disbursed funds fall far short of centrally determined budget ceilings, and the funds are sent late; Council Health Management Teams (CHMT) develop budgets but are restricted on the percentage they can allocate to different areas – so there is severe under-funding of disease prevention and health promotion initiatives at the community level.Conclusion: This study has identified achievements that should be further nurtured and challenges that should be worked on for the improvement of the decentralized health system. Thus, as a way forward, it is recommended that the equitable allocation of resources should go beyond the recurrent costs for the delivery of health services.
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| 47. |
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| 48. |
- Ortega, F. B., et al.
(författare)
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Role of socio-cultural factors on changes in fitness and adiposity in youth : A 6-year follow-up study
- 2013
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Ingår i: NMCD. Nutrition Metabolism and Cardiovascular Diseases. - : Elsevier BV. - 0939-4753 .- 1590-3729. ; 23:9, s. 883-890
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND AIMS: Optimal cardio-respiratory fitness and adiposity levels are tightly related to health in youth. We analysed changes in fitness and adiposity in young individuals from two countries, and examined the role of maternal education in these changes.METHODS AND RESULTS: A 6-year follow-up study was conducted on 483 Estonian children (9 years) and 466 Swedish children (9-10 years) and adolescents (15 years). Fitness was assessed by a maximal bike test, and total and central adiposity were indirectly estimated by skinfolds (Slaughter's equation for fat mass) and waist circumference. At follow-up, fitness and adiposity had increased in the children cohort (P ≤ 0.001), while small or no change occurred in the adolescent cohort. In the children cohort, Estonian participants had a lower increase in fitness and a higher increase in adiposity (total and central) than Swedish participants. Higher maternal education increased the odds of remaining fit (top quartile) by half and reduced the risk of remaining fat (top quartile) by half; odds ratios = 1.56 (1.00-2.43), 0.50 (0.32-0.77) and 0.61 (0.39-0.94) for fitness, total and central adiposity, respectively.CONCLUSIONS: Our data suggest that the socioeconomic situation of a country might influence key cardiovascular risk factors (fitness and adiposity), being at higher risk for a low-middle income country (Estonia) than a higher income country (Sweden). The findings stress the role of socioeconomic status, particularly maternal education, in the maintenance of healthy fitness and adiposity levels from childhood into later life. Preventive efforts have to be taken from early age.
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| 49. |
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| 50. |
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