Showing papers by "Kjeld Møller Pedersen published in 2017"
112 citations
TL;DR: The multifaceted implementation strategy was cost saving when compared with the usual strategy for implementing LBP clinical practice guidelines in general practice, and the estimate was sensitive to uncertainty.
Abstract: In connection with the publication of a clinical practice guideline on the management of low back pain (LBP) in general practice in Denmark, a cluster randomised controlled trial was conducted. In this trial, a multifaceted guideline implementation strategy to improve general practitioners' treatment of patients with LBP was compared with a usual implementation strategy. The aim was to determine whether the multifaceted strategy was cost effective, as compared with the usual implementation strategy. The economic evaluation was conducted as a cost-utility analysis where cost collected from a societal perspective and quality-adjusted life years were used as outcome measures. The analysis was conducted as a within-trial analysis with a 12-month time horizon consistent with the follow-up period of the clinical trial. To adjust for a priori selected covariates, generalised linear models with a gamma family were used to estimate incremental costs and quality-adjusted life years. Furthermore, both deterministic and probabilistic sensitivity analyses were conducted. Results showed that costs associated with primary health care were higher, whereas secondary health care costs were lower for the intervention group when compared with the control group. When adjusting for covariates, the intervention was less costly, and there was no significant difference in effect between the 2 groups. Sensitivity analyses showed that results were sensitive to uncertainty. In conclusion, the multifaceted implementation strategy was cost saving when compared with the usual strategy for implementing LBP clinical practice guidelines in general practice. Furthermore, there was no significant difference in effect, and the estimate was sensitive to uncertainty.
41 citations
TL;DR: GPs understand defensive actions to be carried out as a result of succumbing to various sources of pressure deriving from the system, the patients, the GPs themselves and peers.
Abstract: Objectives Recent years have witnessed a progressive increase in defensive medicine (DM) in several Western welfare countries. In Danish primary and secondary care, documentation on the extent of DM is lacking. Before investigating the extent of DM, we wanted to explore how the phenomenon is understood and experienced in the context of general practice in Denmark. The objective of the study was to describe the phenomenon of DM as understood and experienced by Danish general practitioners (GPs). Design A qualitative methodology was employed and data were generated through six focus group interviews with three to eight GPs per group (n=28) recruited from the Region of Southern Denmark. Data were analysed using a thematic content analysis inspired by a hermeneutic-phenomenological focus on understanding and meaning. Results DM is understood as unnecessary and meaningless medical actions, carried out mainly because of external demands that run counter to the GP’s professionalism. Several sources of pressure to act defensively were identified by the GPs: the system’s pressure to meet external regulations, demands from consumerist patients and a culture among GPs and peers of infallibility and zero-risk tolerance. Conclusions GPs understand DM as unnecessary and meaningless actions driven by external demands instead of a focus on the patient’s problem. GPs consider defensive actions to be carried out as a result of succumbing to various sources of pressure deriving from the system, the patients, the GPs themselves and peers.
39 citations
TL;DR: In this paper, a plasmonic hot-spot engineering method was proposed for the detection of probe molecules at ultralow concentrations, even at the single-molecule level.
Abstract: The detection of probe molecules at ultralow concentrations, even at the single-molecule level, can be addressed with the breakthrough concept of plasmonic hot-spot engineering. In view of that, the fabrication of nanostructures endowed with sub-10 nm gaps and extremely large near-field enhancement has gained increasing attention, becoming a key-condition for improved sensitivity. The present work demonstrates a new perspective in ultrasensitive detection by engineering every individual plasmonic nanostructure with a giant electric field confinement and superior hot-spot densities, thus eliminating the need for extremely narrow interparticle separations.
35 citations
TL;DR: It is shown that evaluation models using known methods assessing cost-effectiveness are most prevalent in early assessment, but seems ill-suited for early assessment in hospitals.
17 citations
01 Oct 2017
TL;DR: In this paper, a power cycling test of a discrete GaN power device employing a laminated embedded packaging technology subjected to 125 degrees Celsius junction temperature swing is presented, where failure modes are described with collected electrical characteristics and measured temperature data under the test.
Abstract: A GaN-on-Si power device is a strong candidate to replace power components based on silicon in high-end market for low-voltage applications, thanks to its electrical characteristics. To maximize opportunities of the GaN device in field applications, a package technology plays an important role in a discrete GaN power device. A few specialized package technologies having very lower stray inductance and higher thermal conductivity have been proposed for discrete GaN-on-Si power devices. Despite their superior performance, there has been little discussion of their reliability. The paper presents a power cycling test of a discrete GaN power device employing a laminated embedded packaging technology subjected to 125 degrees Celsius junction temperature swing. Failure modes are described with collected electrical characteristics and measured temperature data under the test. In conclusion, physical degradation of a solder layer between a tested discrete chip and an aluminum print circuit board is represented by a scanning acoustic microscope and a scanning electron microscope. A drain-to-source leakage current increase after the failure is reported in resemblance with previous studies.
16 citations
01 Jun 2017
TL;DR: In this article, a double point monitoring concept of the on-state voltage is presented as a means to identify the failure mode early in a power module lifetime, which is carried out in a simple accelerated test setup, however, it is argued that the concepts should be possible in field.
Abstract: A double point monitoring concept of the on-state voltage is presented as a means to identify the failure mode early in a power module lifetime The monitoring approach is carried out in a simple accelerated test setup, however, it is argued that the concepts should be possible in field Additionally, by carrying out the monitoring in calibration conditions it is shown that it is possible to identify the fracture rate of the bond wire fatigue failure mechanism The curve shape of the degradation rate is in accordance with expected fracture theory
16 citations
TL;DR: A large number of bond interfaces are analyzed and they are found to follow conventional accepted fracture laws like Paris-Erdogan, which could enable the possibility of obtaining empirical parameters to be used in actual physics based lifetime laws.
15 citations
TL;DR: Analysis revealed that case management led to a positive incremental QALY, but were more costly than usual care, as the highly uncertain ICER somewhat exceeds the threshold value used by the National Institute of Health and Care Excellence (NICE).
Abstract: To analyse the cost effectiveness of community-based case management for patients suffering from chronic obstructive pulmonary disease (COPD). The study took place in the third largest municipality in Denmark and was conducted as a randomised controlled trial with 12 months of follow-up. A total of 150 patients with COPD were randomised into two groups receiving usual care and case management in addition to usual care. Case management included among other things self care proficiency, medicine compliance, and care coordination. Outcome measure for the analysis was the incremental cost-effectiveness ratio (ICER) as cost per quality-adjusted life year (QALY) from the perspective of the healthcare sector. Costs were valued in British Pounds (£) at price level 2016. Scenario analyses and probabilistic sensitivity analyses were conducted in order to assess uncertainty of the ICER estimate. The intervention resulted in a QALY improvement of 0.0146 (95% CI −0.0216; 0.0585), and a cost increase of £494 (95% CI −1778; 2766) per patient. No statistically significant difference was observed either in costs or effects. The ICER was £33,865 per QALY gained. Scenario analyses confirmed the robustness of the result and revealed slightly lower ICERs of £28,100–£31,340 per QALY. Analysis revealed that case management led to a positive incremental QALY, but were more costly than usual care. The highly uncertain ICER somewhat exceeds for instance the threshold value used by the National Institute of Health and Care Excellence (NICE). No formally established Danish threshold value exists. ClinicalTrials.gov Identifier: NCT01512836.
9 citations
TL;DR: In this article, an approximately 90-100nm thick SiC buffer layer is synthesized using the reaction between Si substrate and CO gas, which reveals sharp crystalline interfaces with epitaxial relationship between SiC/Si and AlN/SiC layers.
Abstract: We report a novel approach for metal organic vapor phase epitaxy of (Al)GaN heterostructures on Si substrates. An approximately 90–100 nm thick SiC buffer layer is synthesized using the reaction between Si substrate and CO gas. High-resolution transmission electron microscopy reveals sharp crystalline interfaces with epitaxial relationship between SiC/Si and AlN/SiC layers. Optimization of SiC morphology and AlN seed layer thickness facilitates the growth of GaN layers free of pits (v-defects). It is also found that Si doping eliminates these defects in the case of growth on SiC templates with non-optimized surface morphology. Thus, synthesis of thin SiC buffer layer is suggested as a solution for the interface problems at the initial stage of III-N on Si epitaxy.
5 citations
TL;DR: Even though a majority of GPs associate SHI with overtreatment and inequality in health, many GPs feel under pressure to refer patients holding SHI for treatments or examinations that are not medically warranted.
Abstract: Background Supplemental health insurances (SHI) cover 38% of the Danish population. SHI can give faster access to, and additional treatment from, private health providers. However, this is contingent on a referral from the general practitioner (GP), further complicating clinical decision-making. Objectives To describe GPs' attitudes to SHI and their experiences with patients holding SHI. Moreover, we analysed associations between different GP characteristics; e.g. gender, age, practice type, own SHI status and their attitudes to and experiences with SHI. Methods A questionnaire was mailed to 3321 GPs focusing on three issues: (i) Attitudes towards the public health care system. (ii) Perceptions of the impact of SHI. (iii) Experiences with patients holding SHIs. Results The response rate was 64%. Overall, GPs found that SHIs contribute to inequality (83%) and overtreatment (90%). However, 46% often feel under pressure to refer SHI patients to specialist care, even though not medically indicated, while 11% always or often refer SHI patients unconditionally. Both groups perceive SHI patients more insistent on getting referrals than patients without SHI. Conclusion Even though a majority of GPs associate SHI with overtreatment and inequality in health, many GPs feel under pressure to refer patients holding SHI for treatments or examinations that are not medically warranted. Some GPs even refer these patients without further examination or questioning. Insistent SHI patients may partly explain this paradox. Future research should illuminate SHI patients' courses in the private as well as the public healthcare system with regards to medical indications and health outcome measures focusing on inequality and overtreatment.
TL;DR: In this paper, the authors proposed amorphous Al2O3 thin film coatings for n-and p-type SiC due to the value of the band gap and the position of its band edges with respect to the band edges of the underlying sem...
Abstract: The development of SiC wafers with properties suitable for electronic device fabrication is now well established commercially. A critical issue for developing metal–oxide–semiconductor field effect transistor devices of SiC is the choice of dielectric materials for surface passivation and insulating coatings. Although SiO2 grown thermally on SiC is a possibility for the gate dielectric, this system has a number of problems related to the higher band gap of SiC, which energetically favors more interface states than for SiO2 on Si, and the low dielectric constant of SiO2 leading to 2.5× higher electric fields across the oxide than in the surface of SiC, and to a premature breakdown at the higher fields and higher temperatures that SiC devices are designed to operate under. As a replacement for SiO2, amorphous Al2O3 thin film coatings have some strong advocates, both for n- and p-type SiC, due to the value of its band gap and the position of its band edges with respect to the band edges of the underlying sem...
TL;DR: In this article, the authors investigated the effect of Fe doping on the nonlinear optical properties and thus indirectly on crystal properties, and found that Fe doping strongly reduces nonlinear luminescence.
Abstract: Unintentionally doped and semi-insulating Fe-doped GaN crystals grown by hydride vapor phase epitaxy have been investigated with two-photon photoluminescence and second-harmonic generation spectroscopy to reveal doping effects on the nonlinear optical properties and thus indirectly on crystal properties. Like for linear luminescence, it is found that Fe doping strongly reduces nonlinear luminescence. Recording of second-harmonic generation spectra in transmission probing bulk properties shows no significant difference between doped and un-doped crystals. Reflected second-harmonic generation probing 50–100 nm at the surface, on the other hand, shows significantly lower signal from the doped sample. Secondary ion mass spectroscopy shows that the Fe concentration is higher at the surface than in the bulk of the doped crystal. It is suggested that this causes higher defect density and degraded order in the surface region, thus reducing the second-harmonic signal.
TL;DR: The article proposes the use of LCA because it is believed to have the potential to enable more appropriate targeting of complex care strategies and indicate that researchers evaluating patient-tailored complex interventions need to address both supply-side variation and demand-side heterogeneity to link findings with outcome.
TL;DR: In this article, the authors theoretically studied how the optics of multiple grooves in a metal change as the number of grooves gradually increased from a single groove to infinitely many arranged in a periodic array.
Abstract: This paper theoretically studies how the optics of multiple grooves in a metal change as the number of grooves gradually increased from a single groove to infinitely many arranged in a periodic array. In the case of a single groove, the out-of-plane scattering (OUP) cross section at resonance can significantly exceed the groove width. On the other hand, a periodic array of identical grooves behaves radically different and is a near-perfect absorber at the same wavelength. When illuminating multiple grooves with a plane wave, the OUP cross section is found to scale roughly linearly with the number of grooves and is comparable with the physical array width even for widths of many wavelengths. The normalized OUP cross section per groove even exceeds that of a single groove, which is explained as a consequence of surface plasmon polaritons generated at one groove being scattered out of the plane by other grooves. In the case of illuminating instead with a Gaussian beam and observing the limit as the incident beam narrows and is confined within the multiple-groove array, it is found that the total reflectance becomes very low and that there is practically no OUP. The well-known result for periodic arrays is thus recovered. All calculations were carried out using Green’s function surface integral equation methods taking advantage of the periodic nature of the structures. Both rectangular and tapered grooves are considered.
TL;DR: In this paper, the authors studied how the optics of multiple grooves in a metal change as the number of grooves is increased gradually from a single groove to infinitely many arranged in a periodic array.
Abstract: This paper studies theoretically how the optics of multiple grooves in a metal change as the number of grooves is increased gradually from a single groove to infinitely many arranged in a periodic array. In the case of a single groove the out-of-plane scattering (OUP) cross section at resonance can significantly exceed the groove width. On the other hand a periodic array of identical grooves behaves radically different and is a near-perfect absorber at the same wavelength. When illuminating multiple grooves with a plane wave the OUP cross section is found to scale roughly linearly with the number of grooves and is comparable to the physical array width even for widths of many wavelengths. The normalized OUP cross section per groove even exceeds that of a single groove, which is explained as a consequence of surface plasmon polaritons generated at one groove being scattered out-of-the-plane by other grooves. In the case of illuminating instead with a Gaussian beam, and observing the limit as the incident beam narrows and is confined within the multiple-groove array, it is found that the total reflectance becomes very low and that there is practically no out-of-plane scattering. The well-known result for periodic arrays is thus recovered. All calculations were carried out using Greens function surface integral equation methods taking advantage of the periodic nature of the structures. Both rectangular and tapered grooves are considered.
Posted Content•
TL;DR: To explore how far the traditional but costly tool used to assess presenteeism behaviour, a questionnaire, could advantageously be replaced by a statistical approach that relies on easily available information on sickness, a zero-inflated binomial regression analysis (ZINB) is used.
Abstract: Presenteeism occurs when an employee attends work while sick or unwell. It is a major Human Resource and organizational issue: in addition to productivity losses, presenteeism is believed to increase sickness absence and decrease self-rated health. However, by its very nature, presenteeism cannot be monitored in the same manner as sickness absence. We show how the probability of presenteeism can be estimated from simple absence data by means of a zero-inflated binomial regression analysis (ZINB). The approach is validated on a Danish data set that contains self-reported sickness absence and presenteeism, whereas causality and reliability are verified by conducting Monte-Carlo simulations. The objective of paper was to explore how far the traditional but costly tool used to assess presenteeism behaviour, a questionnaire, could advantageously be replaced by a statistical approach that relies on easily available information on sickness. We show that the ZINB model captures presenteeism well via the inflation process and delivers insight on both absenteeism and presenteeism. Using Monte Carlo simulations, we further highlight that the model can be used to compute a global indicator, propensity for presenteeism, even when important assumptions are violated.
01 Jan 2017
TL;DR: In this article, a physics-based finite element model of KPFM measurements on dielectrics was developed to investigate the impact of tip-induced polarization on the potential profiles obtained by KPFM.
Abstract: Kelvin probe force microscopy (KPFM) is widely used as characterization tool on functional heterostructures and components but it often suffers from measurement artifacts on such structures because the presence of the biased cantilever tip transforms the actual surface potential. In this work we have developed a physics-based finite element model of KPFM measurements on dielectrics in order to investigate the impact of tip-induced polarization. The model is compared with experiments on film capacitors, where it is found that tip-induced polarization is a significant contributor to the potential profiles obtained by KPFM.