| 1. |
- Jonsson, Ulf G, et al.
(författare)
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Modeling the high-frequency complex modulus of a silicone rubber using standing lamb waves and an inverse finite element method
- 2014
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Ingår i: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control. - : IEEE Press. - 0885-3010 .- 1525-8955. ; 61:12, s. 2106-2120
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Tidskriftsartikel (refereegranskat)abstract
- To gain an understanding of the high-frequency elastic properties of silicone rubber, a finite element model of a cylindrical piezoelectric element, in contact with a silicone rubber disk, was constructed. The frequency dependent elastic modulus of the silicone rubber was modeled by a four parameter fractional derivative viscoelastic model in the 100 kHz to 250 kHz frequency range. The calculations were carried out in the range of the first radial resonance frequency of the sensor. At the resonance, the hyperelastic effect of the silicone rubber was modeled by a hyperelastic compensating function. The calculated response was matched to the measured response by using the transitional peaks in the impedance spectrum that originates from the switching of standing Lamb wave modes in the silicone rubber. To validate the results, the impedance responses of three 5 mm thick silicone rubber disks, with different radial lengths, were measured. The calculated and measured transitional frequencies have been compared in detail. The comparison showed very good agreement, with average relative differences of 0.7 %, 0.6 %, and 0.7 % for the silicone rubber samples with radial lengths of 38.0 mm, 21.4 mm, and 11.0 mm, respectively. The average, complex, elastic modulus of the samples were: (0.97 + 0.009i) GPa at 100 kHz and (0.97 + 0.005i) GPa at 250 kHz.
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| 2. |
- Morgan, G., et al.
(författare)
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Mental state language and quality of conversational experience in deaf and hearing children
- 2014
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Ingår i: Cognitive development. - : Elsevier BV. - 0885-2014. ; 29:1, s. 41-49
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Tidskriftsartikel (refereegranskat)abstract
- Deaf children of hearing parents show a protracted delay in performance on 'theory of mind' measures that suggests they encounter difficulties in acquiring knowledge of false beliefs and other mental states. Considerable evidence indicates that children's early experience of adults' mental state talk predicts their later social-cognitive development. However, no previous study has analyzed very young deaf children's access to conversation about mental states. We compared the conversational turn-taking and input of hearing parents to deaf and hearing children aged 17-35 months in the UK and Sweden. Mothers of hearing children used far more cognitive mental state language with their infants and their conversations were characterized by more communicatively effective turn-taking than mothers of deaf children. Across two different cultures, these findings indicate that conversations differ significantly in these aspects of interaction thought to be crucial for later social-cognitive development. © 2013 Elsevier Inc.
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| 3. |
- Röijezon, Ulrik, et al.
(författare)
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Nordic Dedication to Musicians' Health and Performance : A Successful Launch of the First Nordic Conference
- 2014
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Ingår i: Medical problems of performing artists. - : Science and Medicine, Inc.. - 0885-1158 .- 1938-2766. ; 29:4, s. 243-245
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Tidskriftsartikel (refereegranskat)abstract
- Within the last 30 years performing arts medicine has grown internationally as a scientific and clinical specialty for investigation, examination, treatment, and prevention of disorders among performing arts professionals and amateurs, i.e., dancers, singers, musicians, actors, and others engaged in performing arts. In the Nordic countries, clinical specialization and research regarding the health situation of musicians and other performing artists has been relatively sparse. However, this has gained speed in the last decade and is today a growing field. Musicians' Health and Performance 1st Nordic Conference 2013 took place June 13-14, 2013, at the Acusticum Concert Hall in Piteå in the northern part of Sweden, close to the Arctic circle
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| 4. |
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| 5. |
- Evertsson, Maria, et al.
(författare)
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Multimodal Detection of Iron Oxide Nanoparticles in Rat Lymph Nodes Using Magnetomotive Ultrasound Imaging and Magnetic Resonance Imaging
- 2014
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Ingår i: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control. - 0885-3010. ; 61:8, s. 1276-1283
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Tidskriftsartikel (refereegranskat)abstract
- Detection and removal of sentinel lymph nodes (SLN) is important in the diagnosis and treatment of cancer. The SLN is the first regional lymph node draining the primary tumor, and if the cancer has spread, it is most likely to find metastases in the SLN. In this study, we have for the first time been able to image the very same contrast agent, superparamagnetic iron oxide nanoparticles (SPIO-NPs), in rat SLNs by using both our frequency-and phase-gated magnetomotive ultrasound (MMUS) algorithm and conventional magnetic resonance imaging (MRI); MMUS post mortem, MRI in vivo. For both higher NP-concentration and smaller NPs, we found that the MMUS data showed a larger magnetomotive displacement (1.56 +/- 0.43 and 1.94 +/- 0.54 times larger, respectively) and that the MR-images were affected to a higher degree. The MMUS displacement also increased with lower excitation frequency (1.95 +/- 0.64 times larger for 5 Hz compared with 15 Hz) and higher excitation voltage (2.95 +/- 1.44 times larger for 30 V compared with 10 V). The results show that MMUS has potential to be used as bedside guidance during SLN surgery, imaging the same particles that were used in prior staging with other imaging techniques.
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| 6. |
- Gustafsson, Stefan, et al.
(författare)
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Electromagnetic dispersion modeling and measurements for HVDC power cables
- 2014
-
Ingår i: IEEE Transactions on Power Delivery. - : IEEE Press. - 0885-8977 .- 1937-4208. ; 29:6, s. 2439-2447
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Tidskriftsartikel (refereegranskat)abstract
- This paper provides a general framework for electromagnetic (EM) modeling, sensitivity analysis, computation, and measurements regarding the wave propagation characteristics of high-voltage direct-current (HVDC) power cables. The modeling is motivated by the potential use with transient analysis, partial-discharge measurements, fault localization and monitoring, and is focused on very long (10 km or more) HVDC power cables with transients propagating in the low-frequency regime of about 0-100 kHz. An exact dispersion relation is formulated together with a discussion on practical aspects regarding the computation of the propagation constant. Experimental time-domain measurement data from an 80-km-long HVDC power cable are used to validate the electromagnetic model, and a mismatch calibration procedure is devised to account for the connection between the measurement equipment and the cable. Quantitative sensitivity analysis is devised to study the impact of parameter uncertainty on wave propagation characteristics. The sensitivity analysis can be used to study how material choices affect the propagation characteristics, and to indicate which material parameters need to be identified accurately in order to achieve accurate fault localization. The analysis shows that the sensitivity of the propagation constant due to a change in the conductivity in the three metallic layers (the inner conductor, the intermediate lead shield, and the outer steel armor) is comparable to the sensitivity with respect to the permittivity of the insulating layer. Hence, proper modeling of the EM fields inside the metallic layers is crucial in the low-frequency regime of 0-100 kHz.
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| 7. |
- Jung, Kyungsub, et al.
(författare)
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Arc Stability Control of a High-Power Thyristor Rectifier System in a DC Arc Furnace
- 2014
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Ingår i: IEEE Transactions on Power Electronics. - 0885-8993. ; 29:12, s. 6342-6351
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Tidskriftsartikel (refereegranskat)abstract
- Fundamental features of the arc stability in a dc arc furnace of 720 V/100 kA/72 MW have been investigated. The Cassie-Mayr arc model has been employed and applied for the target dc arc furnace. In order to characterize the parameters of the Cassie-Mayr arc model and the behavior of unstable arc dynamics, the advanced arc simulations of magneto-hydrodynamics (MHD) have been performed. From the results of MHD simulation, the dc arc dynamic resistance is proposed to be an effective arc stability function reflecting the instability of dynamic arc behavior. A control strategy of the 12-pulse thyristor rectifier system to regulate the arc stability function is also proposed in this paper. The simulation and experimental results confirm the usefulness of the proposed dynamic arc resistance as the arc stability function along with the active control strategy. The proposed arc stability function can be regarded as an effective criterion for the overall power conversion system to maintain highly stable arcing operation leading to better productivity and reliability in a dc arc furnace.
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| 8. |
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| 9. |
- Borris, Matthias, et al.
(författare)
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Modelling the effects of changes in rainfall event characteristics on TSS loads in urban runoff
- 2014
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Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 28:4, s. 1787-1796
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Tidskriftsartikel (refereegranskat)abstract
- The effect of changes in rainfall event characteristics on urban stormwater quality, which was described by total suspended solids (TSS), was studied by means of computer simulations conducted with the Storm Water Management Model for a climate change scenario for northern Sweden. The simulation results showed that TSS event loads depended mainly on rainfall depth and intensity, but not on antecedent conditions. Storms with low-to-intermediate depths and intensities showed the highest sensitivity to changes in rainfall input, both for percentage and absolute changes in TSS wash-off loads, which was explained by the contribution of pervious areas and supply limitations. This has significant implications for stormwater management, because those relatively frequent events generally carry a high percentage of the annual pollutant load
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| 10. |
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| 11. |
- Göransson, Kerstin, et al.
(författare)
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Conceptual diversities and empirical shortcomings - a critical analysis of research on inclusive education
- 2014
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Ingår i: European Journal of Special Needs Education. - : Taylor & Francis. - 0885-6257 .- 1469-591X. ; 29:3, s. 265-280
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this paper is to critically analyse research about inclusive education.Prior reviews and the outcome of a recent search of databases are analysedwith regard to (a) how inclusion is defined and (b) what empirical knowledgethere is regarding factors that make schools and classrooms more inclusive. Ourpoint of departure is that we regard inclusion as an idea about what school systems,schools and classrooms should accomplish, and as such, an expression ofan educational philosophy. Four different understandings of inclusive educationwere found: (a) inclusion as the placement of pupils with disabilities in mainstreamclassrooms, (b) inclusion as meeting the social/academic needs of pupilswith disabilities, (c) inclusion as meeting the social/academic needs of all pupilsand (d) inclusion as creation of communities. Under a strict definition of inclusiveeducation, hardly any research was found which reliably identified factorsthat give rise to inclusive processes. The outcome of our analyses are discussedfrom the perspective that different understandings of inclusion should be seen, toa large extent, as expressions of different views of what schools should accomplish.We also propose that some of the adherents to inclusion as creation ofcommunities can be placed in the grand educational tradition reaching back toDewey that tries to establish new ideals for school systems in a society in whichindividualism is perhaps the main ideology. The main conclusions are that theoperative meaning of inclusion in reviews and empirical research should bemuch more clearly defined and that new types of studies are needed.
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| 12. |
- Herkner, Birgitta, 1951-, et al.
(författare)
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Early identification or broken promises? : a comparison of literacy assessment performance in 112 Swedish third graders
- 2014
-
Ingår i: European Journal of Special Needs Education. - : Taylor & Francis Group. - 0885-6257 .- 1469-591X. ; 29:2, s. 237-246
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Tidskriftsartikel (refereegranskat)abstract
- The national standardised literacy assessment (NSLA) for Swedish Language was introduced in 2009 as a grade-three compulsory assessment and includes the assessment of reading ability. It was introduced as a measure of relatively early identification of reading difficulties among nine-years old students. The primary objective of this study was to examine whether the NSLA is able to identify students with word decoding problems from a sample of third graders (N = 112; n = 57 girls; n = 55 boys) attending six schools in a Swedish municipality. Eleven students (10%) performed below the cut-off value for word decoding ability in students of this age group. Only three of these students were identified as not achieving the goals posed by the NSLA. In contrast, eight students with low word decoding ability managed to meet the NSLA requirements. Gender differences were observed, since all of the students who passed the NSLA, notwithstanding having low performance in WD, were boys. Although the NSLA was specifically introduced at this level to identify weakness in reading at an early stage, the results of this study indicate that approximately three quarters of students with poor word decoding ability may remain unidentified by the NSLA. These findings call into question the validity of the NSLA in recognising pupils in need of additional support in reading.
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| 13. |
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| 14. |
- Kothapalli, Veera Venkata Satya Naray, 1985-, et al.
(författare)
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Unique pumping-out fracturing mechanism of a polymer-shelled contrast agent : An acoustic characterization and optical visualization
- 2014
-
Ingår i: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control. - 0885-3010 .- 1525-8955. ; 62:3, s. 451-462
-
Tidskriftsartikel (refereegranskat)abstract
- This work describes the fracturing mechanism of air-filled microbubbles (MBs) encapsulated by a cross-linked poly(vinyl alcohol) (PVA) shell. The radial oscillation and fracturing events following the ultrasound exposure were visualized with an ultrahigh-speed camera, and backscattered timedomain signals were acquired with the acoustic setup specific for harmonic detection. No evidence of gas emerging from defects in the shell with the arrival of the first insonation burst was found. In optical recordings, more than one shell defect was noted, and the gas core was drained without any sign of air extrusion when several consecutive bursts of 1 MPa amplitude were applied. In acoustic tests, the backscattered peak-to-peak voltage gradually reached its maximum and exponentially decreased when the PVA-based MB suspension was exposed to approximately 20 consecutive bursts arriving at pulse repetition frequencies of 100 and 500 Hz. Taking into account that the PVA shell is porous and possibly contains large air pockets between the cross-linked PVA chains, the aforementioned acoustic behavior might be attributed to pumping gas from these pockets in combination with gas release from the core through shell defects. We refer to this fracturing mechanism as pumping-out behavior, and this behavior could have potential use for the local delivery of therapeutic gases, such as nitric oxide.
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| 15. |
- Krabbe, Elsbeth, et al.
(författare)
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Birth month as predictor of ADHD medication use in Dutch school classes
- 2014
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Ingår i: European Journal of Special Needs Education. - : Informa UK Limited. - 0885-6257 .- 1469-591X. ; 29:4, s. 571-578
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Tidskriftsartikel (refereegranskat)abstract
- Several international studies have shown that pupils who are comparatively young within their year group have a greater likelihood of being diagnosed with ADHD and receiving ADHD medication. The findings suggest that compara- tively young but age-appropriate behaviour some pupils show in school may be confused with ADHD. This study investigates whether this noted association between birth month and ADHD medication is also found in the Netherlands; and if so, whether GPs (general practitioners) and teachers are aware of this association. Over 2000 birth dates of children between the ages of 5 and 12 were collected from GP client files. The data included whether children are prescribed methylphenidate, the most commonly used medication for ADHD. These data were analysed by descriptive statistics (graphs) and evaluative statistics (logistic regression analysis and relative risk). GPs and teachers were invited by question- naire to report whether they knew of the association between birth month and ADHD. A significant correlation between birth month and methylphenidate pre- scription are found. Relatively young pupils are 2.43 times more likely to be pre- scribed methylphenidate than their older classmates. A majority of GPs and teachers report not being aware of an association between birth month and ADHD medication.
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| 16. |
- Milanovic, J. V., et al.
(författare)
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International Industry Practice on Power Quality Monitoring
- 2014
-
Ingår i: IEEE Transactions on Power Delivery. - 0885-8977 .- 1937-4208. ; 29:2, s. 934-941
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Tidskriftsartikel (refereegranskat)abstract
- Monitoring of voltages and currents at system buses gives the network operators information about the performance of their network, both for the system as a whole and for individual locations and customers. There is also demand from the customers and the regulatory agencies to provide information on the actual power-quality (PQ) level. Developments in enabling technology have made it possible to monitor at a large scale and to record virtually any PQ parameter of interest. While many network operators are installing monitoring equipment and while more and more monitors are available, there is a lack of knowledge and agreement on a number of aspects of the monitoring process and on processing the recorded data. As a response to this lack of uniformity in approach, data acquisition, and processing, in February 2011, CIGRE and CIRED established the Joint Working Group C4.112: “Guidelines for Power quality monitoring—measurement locations, processing and presentation of data.” In order to identify the current international industry practice on PQ monitoring, the group carried out a survey in 43 countries across the world. This paper summarizes the key findings from 114 responses to the questionnaire and identifies prevalent industrial practice in PQ monitoring around the world.
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| 17. |
- Nasri, Amin, et al.
(författare)
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Minimizing Wind Power Spillage Using an OPF With FACTS Devices
- 2014
-
Ingår i: IEEE Transactions on Power Systems. - : IEEE Press. - 0885-8950 .- 1558-0679. ; 29:5, s. 2150-2159
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Tidskriftsartikel (refereegranskat)abstract
- This paper proposes an optimal power flow (OPF) model with flexible AC transmission system (FACTS) devices to minimize wind power spillage. The uncertain wind power production is modeled through a set of scenarios. Once the balancing market is cleared, and the final values of active power productions and consumptions are assigned, the proposed model is used by the system operator to determine optimal reactive power outputs of generating units, voltage magnitude and angles of buses, deployed reserves, and optimal setting of FACTS devices. This system operator tool is formulated as a two-stage stochastic programming model, whose first-stage describes decisions prior to uncertainty realization, and whose second-stage represents the operating conditions involving wind scenarios. Numerical results from a case study based on the IEEE RTS demonstrate the usefulness of the proposed tool.
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| 18. |
- Nordström, Lars, et al.
(författare)
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A Multi-Disciplinary Course Portfolio on Computer Applications in Power Systems
- 2014
-
Ingår i: IEEE Transactions on Power Systems. - 0885-8950 .- 1558-0679. ; 29:4, s. 1919-1927
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Tidskriftsartikel (refereegranskat)abstract
- As a response to the new requirements posed by the shift towards Smartgrids, there have been many initiatives worldwide to develop and update power engineering education curricula. This paper reports efforts to develop courses with the purpose to cross the gap between the disciplines of power engineering and information communication technology at KTH-the Royal Institute of Technology in Sweden. The course portfolio is engineered to complement several master programs offered by the university, and the intended audience are students and practitioners both with and without the power engineering background. This paper primarily focuses on details of a keystone course, Computer Applications in Power Systems, and its connection with the other courses in the portfolio. To prove the popularity and relevance of the reported course portfolio, increasingly positive feedback from students, recognition from industry partners, and accomplishments in terms of meeting several strategic goals in education set by the IEEE Power & Energy Society are also reported by this paper.
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| 19. |
- Nursebo, Shemsedin, 1983, et al.
(författare)
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Optimizing Wind Power Hosting Capacity of Distribution Systems Using Cost Benefit Analysis
- 2014
-
Ingår i: IEEE Transactions on Power Delivery. - : Institute of Electrical and Electronics Engineers (IEEE). - 0885-8977 .- 1937-4208. ; 29:3, s. 1436-1445
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Tidskriftsartikel (refereegranskat)abstract
- The penetration of wind power into the electricity grid is growing significantly. A significant portion of this wind power is being installed in distribution systems, of which most are passively operated. Under this operating practice, wind power can only be admitted based on minimum load and maximum generation consideration. This severely limits the wind power hosting capacity of the system. Hence, the use of active-management strategies (AMSs) has been proposed to increase the hosting capacity of distribution systems. This paper incorporates AMSs into two optimization models whose objectives are to maximize the net benefit of distribution system operator and wind farm owner, respectively. The AMSs considered are wind energy curtailment, coordinated on-load tap changer voltage control, and reactive power compensation. The models development is based on a typical medium-voltage distribution system in Sweden although it can easily be adapted to other cases. The application of the model to a distribution system in Sweden shows an increase in hosting capacity of the distribution system by 78% with mere 2.6% curtailed energy. That is, the hosting capacity of the distribution system has almost been doubled by using AMSs.
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| 20. |
- Peftitsis, Dimosthenis, et al.
(författare)
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Self-Powered Gate Driver for Normally-ON SiC JFETs : Design Considerations and System Limitations
- 2014
-
Ingår i: IEEE transactions on power electronics. - 0885-8993 .- 1941-0107. ; 29:10, s. 5129-5135
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Tidskriftsartikel (refereegranskat)abstract
- A circuit solution to the normally-ON property of the normally-ON silicon carbide junction field-effect transistor, namely the self-powered gate driver, has been recently proposed. This letter sheds some light on the design process of the self-powered gate driver concept as well as limitations from the system perspective. It is experimentally shown that the parameters of the self-powered gate driver must be chosen taking into account a tradeoff between a fast response and stable operation of the driver. Moreover, the influence of the shoot-through current in the fast activation of the self-powered gate driver is also presented.
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| 21. |
- Samadi, Afshin, 1982-, et al.
(författare)
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Coordinated Active Power-Dependent Voltage Regulation in Distribution Grids With PV Systems
- 2014
-
Ingår i: IEEE Transactions on Power Delivery. - 0885-8977 .- 1937-4208. ; 29:3, s. 1454-1464
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Tidskriftsartikel (refereegranskat)abstract
- High penetrations of photovoltaic (PV) systems in distribution grids have brought about new challenges such as reverse power flow and voltage rise. One of the proposed remedies for voltage rise is reactive power contribution by PV systems. Recent German Grid Codes (GGC) introduce an active power dependent (APD) standard characteristic curve, Q(P), for inverter-coupled distributed generators. This study utilizes the voltage sensitivity matrix and quasi-static analysis in order to locally and systematically develop a coordinated Q(P) characteristic for each PV system along a feeder. The main aim of this paper is to evaluate the technical performance of different aspects of proposed Q(P) characteristics. In fact, the proposed method is a systematic approach to set parameters in the GGC Q(P) characteristic. In the proposed APD method the reactive power is determined based on the local feed-in active power of each PV system. However, the local voltage is also indirectly taken into account. Therefore, this method regulates the voltage in order to keep it under the upper steady-state voltage limit. Moreover, several variants of the proposed method are considered and implemented in a simple grid and a complex utility grid. The results demonstrate the voltage-regulation advantages of the proposed method in contrast to the GGC standard characteristic.
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| 22. |
- Sturk, Christopher, et al.
(författare)
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Coherency-Independent Structured Model Reduction of Power Systems
- 2014
-
Ingår i: IEEE Transactions on Power Systems. - 0885-8950 .- 1558-0679. ; 29:5, s. 2418-2426
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Tidskriftsartikel (refereegranskat)abstract
- This paper proposes a new model reduction algorithm for power systems based on an extension of balanced truncation. The algorithm is applicable to power systems which are divided into a study area which requires a high-fidelity model and an external area, making up most of the power system, which is to be reduced. The division of the power system can be made arbitrarily and does not rely on the identification of coherent generators. The proposed algorithm yields a reduced order system with a full non-linear description of the study area and a reduced linear model of the external area.
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| 23. |
- Tjernberg, Catharina, et al.
(författare)
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Inclusion in practice : a matter of school culture
- 2014
-
Ingår i: European Journal of Special Needs Education. - : Taylor & Francis. - 0885-6257 .- 1469-591X. ; 29:2, s. 247-256
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Tidskriftsartikel (refereegranskat)abstract
- The main aim of this study was to find out how reading and writing education can work successfully in practice without being exclusive. The teachers preferred heterogenous groups and emphasised the importance of various teaching methods and approaches so as to be able to deal with student diversity. They had a good theoretical foundation and the ability to link-up their theoretical knowledge with what they learned from experience to create action-oriented knowledge. The importance of each student being challenged in the next development zone was stressed. The teachers’ positive belief in their students’ ability and their commitment to the pedagogical process were other central factors. The successful results of the teachers’ work showed the importance of mentorship, co-operation with colleagues and continuous pedagogical discussions, led by a researching teacher, so as to promote the teachers’ own reflective ability. This created an inclusive school culture in which all the students felt they were competent, valued and never excluded.
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| 24. |
- Tohidi, Yaser, et al.
(författare)
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Multi-Regional Transmission Planning as a Non-Cooperative Decision-Making
- 2014
-
Ingår i: IEEE Transactions on Power Systems. - 0885-8950 .- 1558-0679. ; 29:6, s. 2662-2671
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Tidskriftsartikel (refereegranskat)abstract
- This paper discusses the transmission planning problem in a transmission network with multiple transmission planners. Each transmission planner is responsible for a region of the transmission network and maximizes its own region social welfare taking into account the transmission planning decisions of other transmission planners. The mathematical formulation of non-cooperative transmission planning problem is proposed. This problem is modeled using the multiple-leaders single-follower game in applied mathematics. The solution concept of the worst-Nash equilibrium is introduced to solve the set-up game. Different mathematical techniques are employed to formulate the worst-Nash equilibrium solution as a mixed-integer linear programming problem. A discussion on two possible applications of the derived mathematical structure is provided. The computational complexity is also discussed. The Three-Region IEEE-RTS96 example system is employed and modified to suit the purpose of analysis. The cooperative solution where the transmission planners merge into one single transmission planner is assumed as the benchmark in this study. The cooperative transmission planning is formulated in Appendix A of the paper. The results demonstrate the utility of the proposed solution in multi-regional transmission planning.
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| 25. |
- von Ahlefeld Nisser, Désirée, 1953-, et al.
(författare)
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Consultation in special needs education in Sweden and Finland : a comparative approach
- 2014
-
Ingår i: European Journal of Special Needs Education. - : Routledge. - 0885-6257 .- 1469-591X. ; 29:3, s. 297-312
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Tidskriftsartikel (refereegranskat)abstract
- The article compares the conditions and implementation of special education professionals’ consulting task in Sweden and Finland. The article first describes the background of the consulting teacher role and special education in Sweden and in Finland. Two different perspectives in the continuum on consultation are presented, followed by a description of how the consulting task is implemented and described in educational policy papers, and in research in the two countries. The analysis shows that while there are differences between the implementation of the consulting task in Sweden and Finland, there are also several similarities regarding the challenges faced. Differences can be understood according to traditions, education, and educational policy papers. The similarities shows that the consulting task must be clearly defined in policy documents, highlighted in education, and understood as a complex activity where both advice and reflection strategies are used. The consulting task can be more successful if the consultation is characterized by collaborative dialogues where the classroom teachers’ knowledge and the context are also taken in account.
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| 26. |
- Vorobiev, Andrei, 1963, et al.
(författare)
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Impact of the electrode material and shape on performance of intrinsically tunable ferroelectric FBARs
- 2014
-
Ingår i: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control. - 0885-3010. ; 61:5, s. 840-848
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Tidskriftsartikel (refereegranskat)abstract
- Experiment-based analysis of losses in tunable ferroelectric xBiFeO 3-(1-x)BaTiO3 (BF-BT) film bulk acoustic wave resonators (FBARs) is reported. The Q-factors, effective coupling coefficients, and tunabilities are considered as functions of surface roughness of the ferroelectric film, the acoustic impedance and shape of the electrodes/ interconnecting strips, leakage of acoustic waves into the substrate via Bragg reflector, and the relative thicknesses of the electrodes and ferroelectric film. Compared with Al, the high acoustic impedance of Pt electrodes provides higher Q-factor, coupling coefficient, and tunability. However, using Pt in the interconnecting strips results in reduction of the Q-factor.
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| 27. |
- Warda, Peter
(författare)
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Labor demand: the role of imports in production
- 2014
-
Ingår i: The international trade journal. - : Informa UK Limited. - 0885-3908 .- 1521-0545. ; 28:4, s. 363-386
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Tidskriftsartikel (refereegranskat)abstract
- Can import quality affect firms’ labor demand? In this article I analyze how high- and low-quality imports affect labor demand in importing firms in Swedish manufacturing. The largest variation is observed in medium- and large-sized firms. In large firms, an increase in high-quality imports on average reduces the demand for highly educated labor—a substitution effect in production. In medium-sized firms, the effect is the opposite, thus indicating production complementarities. The largest effect, however, is observed in micro-sized firms, where a 1% increase in high-quality imports on average increases the amount of highly educated labor by 0.021%. High- and low-quality imports tend to affect the demand for low-educated labor positively in all firm size categories, hence favoring complementarity effects in production.
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| 28. |
- Åge, Lars-Johan, 1966-, et al.
(författare)
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Editorial
- 2014
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Ingår i: Journal of business & industrial marketing. - 0885-8624 .- 2052-1189. ; 29:7/8, s. 561-
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Contemporary managers regularly face complex multifunctional problems. Unfortunately, researchers are not always there to help them. The research conducted within the business-to-business (B2B) field is often of a high quality and magnitude, but does not always seem to reach managers to a great extent. There are also signs that the gap between managers and researchers could be especially significant when it comes to industrial marketing (Brennan and Turnbull, 2000, 2002; Ankers and Brennan, 2002). We believe that this development could jeopardize the long-term health of the B2B marketing field and that further elaboration is called for; hence, this special issue. We are not alone −82 per cent of B2B marketing researchers believe it is “important” or “very important” for research to be of potential value to managers (Brennan and Turnbull, 2000).Despite the fact that almost all published articles have a section on how results could be of use for managers, these managerial implications are somehow out of reach for most managers. This special issue is dedicated to exploring and enhancing the understanding of the gap between managers and researchers – why it is there, what it consists of – and presenting various perspectives on how it can be bridged, or at least narrowed.The first two articles serve as introductions to the discussion of this issue, by giving a feel for what managerial implications typically look like in contemporary articles within our field. The first article, by Salminen, Oinonen and Haimala, provides insights into the character of managerial implications in articles on the theme of solution business; it does this by applying Jaworski’s (2011) framework for role-relevant research to classify the implications. Baraldi, La Rocca and Perna’s article assesses the characteristics of managerial implications in 60 most-cited articles within B2B marketing. The implications are classified in terms of features that the authors believe have an impact on the ready to use quality of findings for managers (e.g. how easy is it to find implications in the text, the extent to which scientific language is used and how concrete the implications are, etc.).While these first two articles concern the researcher side of the gap – that is, the characteristics of what is “posted to managers” under the managerial implications headline – the third article, by Kusuula, Närvänen, Saarijärvi and Yrjölä, accounts for the manager side of the gap; that is, top executives’ perceptions regarding academia’s results, as addressed to them. Using these opinions as a backdrop, the authors list the relevance challenges for B2B marketing by using a framework developed by Arndt (1985) regarding scientific balance.The six remaining articles in this special issue focus on how the gap between managers and researchers can be narrowed. Brennan, Tzempelikos and Wilson’s article takes a process view of research and lists critical structural elements and communication areas in which further improvement is needed for academia to reach out to managers. Their recommendations concern four groups of stakeholders: researchers, practitioners, policymakers and academic managers.The next five articles have a distinct common theme: one of the major reasons for the widening division between researchers and practitioners is the fact that managers’ realities are characterized by an immense complexity that research has not been able to keep up with. The authors of these articles are unanimous in arguing that the relevance of our research will increase if it manages to embrace complexity to a greater extent, rather than reducing it at early stages in the research process. These articles also underscore the need to reconsider the nature of the methodological approach that researchers use.The first in this set of articles, by Guiette, Matthyssens and Vandenbempt, argues that complexity calls for a more mindful approach to organizing (by both researchers and practitioners) to better understand and manage strategic change processes. By this, they mean that (business) marketing on a strategic level has little to offer in the way of guidance, taking complexity, interdependence and emergence into account. The next two articles emphasize the need for broader, more condensed and abstract conceptualizations to grasp this complexity, which will enhance the relevance for managers. For better real-world-based theories, Gummesson argues that we should strive to establish comprehensive and abstract theories that have the potential to “boil down” complexity to its core, and that this can be accomplished by case theory, and more involved (action) research.Based on the grounded theory methodology, Gustavsson and Åge deliver further recommendations for research in terms of how to create abstract conceptualizations that are able to capture core processes, and they also discuss the possible intricacies involved in such endeavors. The study by Åge shows how managers in three different companies have actually used such abstract conceptualizations as creative devices to tackle challenges. Cederlund emphasizes the role of managerial relevance in the research process – an underrated opportunity for theoretical developments within B2B marketing – which ties together the discussions in the preceding four articles. By placing practice in a research process perspective, she highlights the epistemological remedies for closing the relevance gap and illustrates why managerial relevance is not prioritized on the research agenda.In total, the nine contribute to this special issue’s aim of providing a more nuanced picture of what managerial relevance is and why it is needed. Our aim is to create the platform for a discussion that favors the development of the B2B marketing filed.
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| 29. |
- Meena, Raveesh, et al.
(författare)
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Data-driven models for timing feedback responses in a Map Task dialogue system
- 2014
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Ingår i: Computer speech & language (Print). - : Elsevier BV. - 0885-2308 .- 1095-8363. ; 28:4, s. 903-922
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Tidskriftsartikel (refereegranskat)abstract
- Traditional dialogue systems use a fixed silence threshold to detect the end of users' turns. Such a simplistic model can result in system behaviour that is both interruptive and unresponsive, which in turn affects user experience. Various studies have observed that human interlocutors take cues from speaker behaviour, such as prosody, syntax, and gestures, to coordinate smooth exchange of speaking turns. However, little effort has been made towards implementing these models in dialogue systems and verifying how well they model the turn-taking behaviour in human computer interactions. We present a data-driven approach to building models for online detection of suitable feedback response locations in the user's speech. We first collected human computer interaction data using a spoken dialogue system that can perform the Map Task with users (albeit using a trick). On this data, we trained various models that use automatically extractable prosodic, contextual and lexico-syntactic features for detecting response locations. Next, we implemented a trained model in the same dialogue system and evaluated it in interactions with users. The subjective and objective measures from the user evaluation confirm that a model trained on speaker behavioural cues offers both smoother turn-transitions and more responsive system behaviour.
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| 30. |
- Chung, Sun Ju, et al.
(författare)
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Alpha-Synuclein Repeat Variants and Survival in Parkinson's Disease
- 2014
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Ingår i: Movement Disorders. - : Wiley. - 0885-3185. ; 29:8, s. 1053-1057
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To determine whether alpha-synuclein dinucleotide repeat (REP1) genotypes are associated with survival in Parkinson's disease (PD). Methods: Investigators from the Genetic Epidemiology of Parkinson's Disease Consortium provided REP1 genotypes and baseline and follow-up clinical data for cases. The primary outcome was time to death. Cox proportional hazards regression models were used to assess the association of REP1 genotypes with survival. Results: Twenty-one sites contributed data for 6,154 cases. There was no significant association between alpha-synuclein REP1 genotypes and survival in PD. However, there was a significant association between REP1 genotypes and age at onset of PD (hazard ratio: 1.06; 95% confidence interval: 1.01-1.10; P value = 0.01). Conclusions: In our large consortium study, alpha-synuclein REP1 genotypes were not associated with survival in PD. Further studies of alpha-synuclein's role in disease progression and long-term outcomes are needed. (C) 2014 International Parkinson and Movement Disorder Society
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| 31. |
- Kalliolia, Eirini, et al.
(författare)
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Plasma Melatonin Is Reduced in Huntington's Disease
- 2014
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Ingår i: Movement Disorders. - : Wiley. - 0885-3185 .- 1531-8257. ; 29:12, s. 1511-1515
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Tidskriftsartikel (refereegranskat)abstract
- This study was undertaken to determine whether the production of melatonin, a hormone regulating sleep in relation to the light/dark cycle, is altered in Huntington's disease. We analyzed the circadian rhythm of melatonin in a 24-hour study of cohorts of control, premanifest, and stage II/III Huntington's disease subjects. The mean and acrophase melatonin concentrations were significantly reduced in stage II/III Huntington's disease subjects compared with controls. We also observed a nonsignificant trend toward reduced mean and acrophase melatonin in premanifest Huntington's disease subjects. Onset of melatonin rise was significantly more temporally spread in both premanifest and stage II/III Huntington's disease subjects compared with controls. A nonsignificant trend also was seen for reduced pulsatile secretion of melatonin. Melatonin concentrations are reduced in Huntington's disease. Altered melatonin patterns may provide an explanation for disrupted sleep and circadian behavior in Huntington's disease, and represent a biomarker for disease state. Melatonin therapy may help the sleep disorders seen in Huntington's disease. (c) 2014 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.
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| 32. |
- Aarsland, D, et al.
(författare)
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Psychiatric issues in cognitive impairment
- 2014
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Ingår i: Movement disorders : official journal of the Movement Disorder Society. - : Wiley. - 1531-8257. ; 29:5, s. 651-662
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Tidskriftsartikel (refereegranskat)
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| 33. |
- Abdulahovic, Tarik, 1976, et al.
(författare)
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Voltage Stress in a Transformer Winding During Very Fast Transients Caused by Breaker Closing Event
- 2014
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Ingår i: IEEE Transactions on Power Delivery. - 0885-8977 .- 1937-4208. ; 29:4, s. 1946-1954
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Tidskriftsartikel (refereegranskat)abstract
- Transformers connected at the medium-voltage level in cable grids, such as wind park collection grids and industrial grids, are exposed to the stress of very fast transients. These electric transients are mainly generated during breaker switching operations and the rise time of the transient voltage in such systems is much shorter compared to the rise times of transients generated in transmission systems at a high-voltage level. In this paper, the internal voltage stress is studied during very fast transients generated during transformer energization. Instead of using a breaker, the energizing tests are performed using a low-impedance pulse generator that can generate lightning impulse-shaped waveforms and voltage steps with rise times varying between 35 and 500 ns. Experiments show that during very fast transients with a 35-ns rise time and 1-p.u. magnitude, the interturn voltage exceeds the level obtained with a lightning impulse-shaped voltage waveform of 4.4 pu. Furthermore, during a specific switching scenario with delta-connected transformers, where the winding is excited from both ends, the same 1-p.u./35-ns voltage step generates an interturn voltage that exceeds the 1-p.u. level, which is more than 2.5 times higher voltage stress than during a lightning impulse test.
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| 34. |
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| 35. |
- Alexanderson, Simon, et al.
(författare)
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Animated Lombard speech : Motion capture, facial animation and visual intelligibility of speech produced in adverse conditions
- 2014
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Ingår i: Computer speech & language (Print). - : Elsevier BV. - 0885-2308 .- 1095-8363. ; 28:2, s. 607-618
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we study the production and perception of speech in diverse conditions for the purposes of accurate, flexible and highly intelligible talking face animation. We recorded audio, video and facial motion capture data of a talker uttering a,set of 180 short sentences, under three conditions: normal speech (in quiet), Lombard speech (in noise), and whispering. We then produced an animated 3D avatar with similar shape and appearance as the original talker and used an error minimization procedure to drive the animated version of the talker in a way that matched the original performance as closely as possible. In a perceptual intelligibility study with degraded audio we then compared the animated talker against the real talker and the audio alone, in terms of audio-visual word recognition rate across the three different production conditions. We found that the visual intelligibility of the animated talker was on par with the real talker for the Lombard and whisper conditions. In addition we created two incongruent conditions where normal speech audio was paired with animated Lombard speech or whispering. When compared to the congruent normal speech condition, Lombard animation yields a significant increase in intelligibility, despite the AV-incongruence. In a separate evaluation, we gathered subjective opinions on the different animations, and found that some degree of incongruence was generally accepted.
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| 36. |
- Almquist, Martin, et al.
(författare)
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Atmospheric Sound Propagation Over Large-Scale Irregular Terrain
- 2014
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Ingår i: Journal of Scientific Computing. - : Springer Science and Business Media LLC. - 0885-7474 .- 1573-7691. ; 61:2, s. 369-397
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Tidskriftsartikel (refereegranskat)abstract
- A benchmark problem on atmospheric sound propagation over irregular terrain has been solved using a stable fourth-order accurate finite difference approximation of a high-fidelity acoustic model. A comparison with the parabolic equation method and ray tracing methods is made. The results show that ray tracing methods can potentially be unreliable in the presence of irregular terrain.
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| 37. |
- Alonso, Fabiola, et al.
(författare)
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Comparison of deep brain stimulation systems
- 2014
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Ingår i: Poster Presentations. - : Wiley. ; , s. 1173-1173
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Objective: To quantitatively compare the electric field generated by voltage and current controlled deep brain stimulation systems.Background: Traditionally deep brain stimulation (DBS) systems have used voltage control however more recently, current controlled systems have been approved to treat Parkinson's disease and related movement disorders. In the endeavor of understanding the behavior of DBS systems a common approach is the use of computer models suitable to simulate the electric field, current density and other related electric parameters.Methods: 2D finite element models based on commercially available DBS systems have been built for each system: I. Model 3389, Medtronic Inc., USA for voltage control; and II. Model 6142, St Jude Medical Inc. USA for current control. The brain tissue has been simplified to homogeneous and isotropic medium. The electric settings correspond to a monopolar configuration, using one of the four contacts available as the active electrode and the outer boundary of the tissue as the reference. Three simulations were performed to mimic different stages of the leads implantation: a) an original stage where the brain tissue is considered as pure gray matter, b) an acute stage that simulates the leakage of cerebral spinal fluid immediately after the electrodes' insertion; and c) a chronic stage mimicking fibrous tissue created around the electrodes some weeks after implantation. Both systems were submitted to the same conditions using as active electrode the third contact from the tip of the lead. The comparison is based on the maximal distance reached by the isopotential of 0.2 V/mm.Results: The simulations showed that voltage controlled stimulation systems are more susceptible to changes in the electrical conductivity of the medium i.e. change over time of the tissue around the electrode. This agrees with the adjustment of the stimulation amplitude often necessary a few weeks postoperatively. Current controlled stimulation in turn, presented a linear behavior of the distance reached at different stimulation amplitudes at all stages.Conclusions: Current controlled stimulation might be a good option due to its linear behavior over time, nevertheless more studies including a more realistic brain model, different designs of DBS electrodes and different electric parameter, are needed to encourage the use of this type of systems.
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| 38. |
- Alvehag, Karin, et al.
(författare)
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Impact of Reward and Penalty Scheme on the Incentives for Distribution System Reliability
- 2014
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Ingår i: IEEE Transactions on Power Systems. - 0885-8950 .- 1558-0679. ; 29:1, s. 386-394
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Tidskriftsartikel (refereegranskat)abstract
- Performance-based regulations accompanied by quality regulations are gaining ground in the electricity distribution business. Several European countries apply quality regulations with reward and penalty schemes (RPSs), where the distribution system operator (DSO) is rewarded (or penalized) when fulfilling (or not fulfilling) an adequate level of reliability to its customers. This paper develops a method that the regulator can use before enforcing a regulation to get an understanding of the impact different RPS design solutions have on the DSO's financial risk and incentives to invest in reliability. The proposed method also includes a sensitivity analysis to identify which are the most important parameters in an RPS. The new method is applied to three regulatory challenges to evaluate their RPS design solutions. Results show that the choice of scheme design and cost model used to decide the incentive rate have a large impact on the DSO's financial risk and incentive to invest.
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| 39. |
- Andersen, Martin S., et al.
(författare)
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Reduced-Complexity Semidefinite Relaxations of Optimal Power Flow Problems
- 2014
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Ingår i: IEEE Transactions on Power Systems. - : Institute of Electrical and Electronics Engineers (IEEE). - 0885-8950 .- 1558-0679. ; 29:4, s. 1855-1863
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Tidskriftsartikel (refereegranskat)abstract
- We propose a new method for generating semidefinite relaxations of optimal power flow problems. The method is based on chordal conversion techniques: by dropping some equality constraints in the conversion, we obtain semidefinite relaxations that are computationally cheaper, but potentially weaker, than the standard semidefinite relaxation. Our numerical results show that the new relaxations often produce the same results as the standard semidefinite relaxation, but at a lower computational cost.
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| 40. |
- Anvari, Ebrahim, et al.
(författare)
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The H-1-Receptor Antagonist Cetirizine Protects Partially Against Cytokine- and Hydrogen Peroxide-Induced beta-TC6 Cell Death In Vitro
- 2014
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Ingår i: Pancreas. - 0885-3177 .- 1536-4828. ; 43:4, s. 624-629
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Tidskriftsartikel (refereegranskat)abstract
- Objective It has been proposed that the histamine 1 (H-1) receptor not only promotes allergic reactions but also modulates autoimmune diseases, such as type 1 diabetes. In line with this, it has recently been reported that the H-1-receptor antagonist cetirizine can counteract the activation of signals/factors pertinent to the pathogenesis of type 1 diabetes and cytokine-induced beta-cell destruction. Therefore, the overall aim of this study was to determine whether H-1-receptor antagonists affect cytokine-induced beta-cell death and signaling in vitro. Methods The insulin-producing cell line beta-TC6 was exposed to the proinflammatory cytokines interleukin 1 beta(+) interferon gamma, or hydrogen peroxide. The H-1-receptor antagonists desloratadine and cetirizine were added to the cell cultures and cell viability; macrophage inhibitory factor levels, c-Jun N-terminal kinase phosphorylation, c-Jun expression, and beta-catenin levels were analyzed by flow cytometry, real-time polymerase chain reaction, and immunoblotting. Results Cetirizine protected partially against both cytokine- and hydrogen peroxide-induced cell death. This effect was paralleled by an inhibition of cytokine-induced c-Jun N-terminal kinase phosphorylation, c-Jun induction, and a restoration of macrophage inhibitory factor contents. Cetirizine also increased the beta-TC6 cell contents of beta-catenin at basal conditions. Conclusions Our results indicate a protective effect of a specific H-1-receptor antagonist.
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| 41. |
- Arving, Cecilia, et al.
(författare)
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Registered Nurses' Thoughts on Blended Learning in a Postgraduate Course in Cancer care : Content Analyses of Web Surveys and a Focus Group Interview
- 2014
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Ingår i: Journal of Cancer Education. - : Springer Science and Business Media LLC. - 0885-8195 .- 1543-0154. ; 29:2, s. 278-283
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Tidskriftsartikel (refereegranskat)abstract
- Purpose of the research was to describe registered nurses' (RNs) (n = 53) thoughts on the blended learning format in a 'specialist nursing programme in cancer care'. The study was conducted in autumn 2007 and 2008. A content analysis of answers to open-ended questions in a web-based questionnaire and a focus group interview were carried out. The analysis revealed that the RNs appreciated blended learning. The web lectures facilitated learning and gave RNs access to the education at any time. However, according to the RNs, knowledge is gained through interaction between RNs and teachers, and this aspect needed to be improved. The RNs also thought that the content of the seminars on campus should focus on evidence-based nursing knowledge and practical skills, not just taught as stable facts and procedures. The result from the present study could help to improve the design and content of advanced nursing courses using a blended learning format.
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| 42. |
- Bahmani, Amin, 1985, et al.
(författare)
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An Accurate Pseudoempirical Model of Winding Loss Calculation in HF Foil and Round Conductors in Switchmode Magnetics
- 2014
-
Ingår i: IEEE Transactions on Power Electronics. - 0885-8993 .- 1941-0107. ; 29:8, s. 4231 - 4246
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Tidskriftsartikel (refereegranskat)abstract
- When operating higher up in frequency, the copper losses in transformer windings will significantly rise due to enhanced skin and proximity effect. This leads to a high need to develop new methods to accurately evaluate winding losses at higher frequencies. This paper investigates the effect of different geometrical parameters at a wide range of frequencies in order to propose a pseudoempirical formula for winding loss calculation in high-frequency transformers. A comprehensive analysis of the edge effect and ac resistance is done by performing more than 12 300 2-D finite element simulations on foil and round conductors. Unlike previous studies which mostly focused on specific case studies with limited applications, this model provides very high accuracy, especially where the most common analytical models drastically underestimate the winding losses, with a wide-range applicability which could be of interest for designers to avoid time consuming FEM simulation without compromising with the accuracy. Several transformers are built and the model is experimentally verified with a good agreement.
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| 43. |
- Baraldi, Enrico, et al.
(författare)
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Good for science, but which implications for business? : An analysis of the managerial implications in high-impact B2B marketing articles published between 2003 and 2012
- 2014
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Ingår i: Journal of business & industrial marketing. - 0885-8624 .- 2052-1189. ; 29:7-8, s. 574-592
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Tidskriftsartikel (refereegranskat)abstract
- Purpose - The purpose of the article is to identify and analyze the challenges of B2B research relevance from the point of view of top executives.Design/methodology/approach - Ten in-depth interviews with top executives from different B2B industries were conducted and analyzed by using Arndt’s (1985) elements of a healthy discipline, i.e. Knowledge, Problems, and Instruments.Findings - The findings reveal 12 challenges that characterize contemporary B2B research relevance from a top executive perspective.Research limitations/implications - The research offers genuine top executive insight. More research from different perspectives is needed to broaden the understanding of B2B research relevance.Originality/value - Reflecting B2B research with the identified challenges can contribute to better research designs, narrowing the gap between B2B scholars and practitioners. Altogether, it contributes to the health of the B2B discipline. The study also introduces a new approach to analysing research relevance by using the elements of scientific balance.
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| 44. |
- Barkarmo, Sargon, et al.
(författare)
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Enhanced bone healing around nanohydroxyapatite-coated polyetheretherketone implants : An experimental study in rabbit bone
- 2014
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Ingår i: Journal of biomaterials applications. - : Sage Publications. - 0885-3282 .- 1530-8022. ; 29:5, s. 737-747
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To investigate the bone response to threaded polyetheretherketone (PEEK) implants coated with nanohydroxyapatite. Materials and methods: A total of 39 PEEK implants were coated with nanocrystalline hydroxyapatite and 39 uncoated implants were used as controls. The implant surface was characterized by optical interferometry and scanning electron microscope. The implants were inserted in the tibia and femur of 13 rabbits. After 6 weeks of healing, quantitative and qualitative analyses were performed. Results: The test implants showed significantly higher removal torque test values compared with the control group. Histomorphometric evaluation demonstrated higher bone-to-implant contact for the test implants; however, there were no differences in bone area between the groups. Qualitative histological analyses demonstrated inflammatory cellular reactions in close vicinity of both implant surfaces. A two-cell layer of foreign body giant cells was observed irrespective of sample type. Conclusion: Our findings demonstrate that implants with a threaded design render good stability to PEEK in both coated and uncoated implants. Nanohydroxyapatite-coated PEEK implants demonstrated improved bone formation compared with uncoated controls.
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| 45. |
- Bengtsson, Lars, et al.
(författare)
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Long- term change of daily and multi- daily precipitation in southern Sweden
- 2014
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Ingår i: Hydrological Processes. - : Wiley. - 1099-1085 .- 0885-6087. ; 28:6, s. 2897-2911
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Tidskriftsartikel (refereegranskat)abstract
- Daily rain series from southern Sweden with records dating back to the 1870s have been analysed to investigate the trends of daily and multi-day precipitation of different return periods with emphasis on the extremes. Probabilities of extreme storms were determined as continuously changing values based on 25 years of data. An extra set of data was used to investigate changes in Skane, the southernmost peninsula of Sweden. Another 30-year data set of more than 200 stations of a dense gauge network in Skane was used to investigate the relation between very large daily rainfall and annual precipitation. The annual precipitation has increased significantly all over southern Sweden due to increased winter precipitation. There is a trend of increasing maximum annual daily precipitation at only one station, where the annual maximum often occurs in winter. The number of events with a short return period is increasing, but the number of more extreme events has not increased. Daily and multi-daily design storms of long return periods determined from extreme value analysis with updating year by year are not higher today than during the last 100 years. The largest daily storms are not related to stations with annual rainfall but seem to occur randomly. Copyright (c) 2013 John Wiley & Sons, Ltd.
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| 46. |
- Bergman, Anders, et al.
(författare)
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Enabling DC-Side Metering in HVDC Stations
- 2014
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Ingår i: IEEE Transactions on Power Delivery. - : Institute of Electrical and Electronics Engineers (IEEE). - 0885-8977 .- 1937-4208. ; 29:1, s. 370-377
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Tidskriftsartikel (refereegranskat)abstract
- HVDC power transmission is now being considered not only for point-to-point interties, but also as true grids where several operators may tie into the grid, each having its own economic sphere. In this new situation, it is important that transmitted energy be distinguished from losses incurred in the converter stations, to enable a fair distribution of costs for grid operation. To this end, a metrology infrastructure is needed where high-current and high-voltage transducers must be possible to calibrate traceably, and where dc electricity meters can be calibrated and approved. A research project is currently working with these questions in a concerted European research effort, funded by the European Commission. The present publication highlights important aspects of this work.
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| 47. |
- Beven, Keith J., et al.
(författare)
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GLUE : 20 years on
- 2014
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Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 28:24, s. 5897-5918
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Forskningsöversikt (refereegranskat)abstract
- This paper reviews the use of the Generalized Likelihood Uncertainty Estimation (GLUE) methodology in the 20 years since the paper by Beven and Binley in Hydrological Processes in (1992), which is now one of the most highly cited papers in hydrology. The original conception, the on-going controversy it has generated, the nature of different sources of uncertainty and the meaning of the GLUE prediction uncertainty bounds are discussed. The hydrological, rather than statistical, arguments about the nature of model and data errors and uncertainties that are the basis for GLUE are emphasized. The application of the Institute of Hydrology distributed model to the Gwy catchment at Plynlimon presented in the original paper is revisited, using a larger sample of models, a wider range of likelihood evaluations and new visualization techniques. It is concluded that there are good reasons to reject this model for that data set. This is a positive result in a research environment in that it requires improved models or data to be made available. In practice, there may be ethical issues of using outputs from models for which there is evidence for model rejection in decision making. Finally, some suggestions for what is needed in the next 20 years are provided.
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| 48. |
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| 49. |
- Blomqvist, Johanna, et al.
(författare)
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Temperature-dependent changes in the microbial storage flora of birch and spruce sawdust
- 2014
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Ingår i: Biotechnology and Applied Biochemistry. - : Wiley. - 0885-4513 .- 1470-8744. ; 61, s. 58-64
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Tidskriftsartikel (refereegranskat)abstract
- Sawdust can be used to make pellets (biofuel) and particle boards and as a potential lignocellulose feedstock in bioethanol production. Microbial activity can affect sawdust quality; hence, we monitored the microbial population in birch- and spruce sawdust after 3 months' storage at various temperatures. Species composition was similar on both materials but was strongly influenced by temperature. Bacteria were present on all materials at all conditions: on birch, 2.8x10(8), 1.1x10(8), and 8.8x10(6), and on spruce, 4.1x10(8), 5.6x10(7), and 1.5x10(8)CFU/g DM, at 2, 20, and 37 degrees C, respectively. Dominant bacteria at 2, 20, and 37 degrees C were Pseudomonas spp. (some Enterobacteriaceae spp. present), Luteibacter rhizovicinus, and Fulvimonas sp., respectively. Pseudomonas spp. were absent at 20 degrees C. Among microfungi, yeasts dominated at 2 degrees C but were absent at 37 degrees C, whereas molds dominated at 20 and 37 degrees C. Common yeasts included Cystofilobasidium capitatum, Cystofilobasidium infirmominiatum, Candida saitoana, Candida oregonensis, and Candida railenensis. Ophiostoma quercus was a common mold at 2 and 20 degrees C, whereas the human pathogens Aspergillus fumigatus and Paecilomyces variotii dominated at 37 degrees C. Attempts to influence the microflora by addition of the biocontrol yeasts, Wickerhamomyces anomalus and Scheffersomyces stipitis, were unsuccessful, as their growth in sawdust was poor to absent.
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| 50. |
- Bou-Francis, Antony, et al.
(författare)
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Assessing cement injection behaviour in cancellous bone : An in vitro study using flow models
- 2014
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Ingår i: Journal of biomaterials applications. - : SAGE Publications. - 0885-3282 .- 1530-8022. ; 29:4, s. 582-594
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Tidskriftsartikel (refereegranskat)abstract
- Understanding the cement injection behaviour during vertebroplasty and accurately predicting the cement placement within the vertebral body is extremely challenging. As there is no standardized methodology, we propose a novel method using reproducible and pathologically representative flow models to study the influence of cement properties on injection behaviour. The models, confined between an upper glass window and a lower aluminium plate, were filled with bone marrow substitute and then injected (4, 6 and 8min after cement mixing) with commercially available bone cements (SimplexP, Opacity+, OsteopalV and Parallax) at a constant flow rate (3mL/min). A load cell was used to measure the force applied on the syringe plunger and calculate the peak pressure. A camera was used to monitor the cement flow during injection and calculate the following parameters when the cement had reached the boundary of the models: the time to reach the boundary, the filled area and the roundness. The peak pressure was comparable to that reported during clinical vertebroplasty and showed a similar increase with injection time. The study highlighted the influence of cement formulations and model structure on the injection behaviour and showed that cements with similar composition/particle size had similar flow behaviour, while the introduction of defects reduced the time to reach the boundary, the filled area and the roundness. The proposed method provides a novel tool for quick, robust differentiation between various cement formulations through the visualization and quantitative analysis of the cement spreading at various time intervals.
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