52 resultados para design-based survey sampling
Resumo:
BACKGROUND Despite the increasing interest in medical education in the German-speaking countries, there is currently no information available on the challenges which medical educators face. To address this problem, we carried out a web-based survey among the members of the Association for Medical Education (Gesellschaft für medizinische Ausbildung, GMA). METHODS A comprehensive survey was carried out on the need for further qualifications, expertise and the general conditions of medical educators in Germany. As part of this study, the educators were asked to list the three main challenges which they faced and which required urgent improvement. The results were analysed by means of qualitative content analysis. RESULTS The questionnaire was completed by 147 of the 373 members on the GMA mailing list (response rate: 39%). The educators named a total of 346 challenges and emphasised the following areas: limited academic recognition for engagement in teaching (53.5% of educators), insufficient institutional (31.5%) and financial support (28.4%), a curriculum in need of reform (22.8%), insufficient time for teaching assignments (18,9%), inadequate teacher competence in teaching methods (18.1%), restricted faculty development programmes (18.1%), limited networking within the institution (11.0%), lack of teaching staff (10.2%), varying preconditions of students (8.7%), insufficient recognition and promotion of medical educational research (5.5%), extensive assessment requirements (4.7%), and the lack of role models within medical education (3.2%). CONCLUSION The medical educators found the biggest challenges which they faced to be limited academic recognition and insufficient institutional and financial support. Consequently, improvements should be implemented to address these issues.
Resumo:
A compact adjustable focusing system for a 2 MeV H- RFQ Linac is designed, constructed and tested based on four permanent magnet quadrupoles (PMQ). A PMQ model is realised using finite element simulations, providing an integrated field gradient of 2.35 T with a maximal field gradient of 57 T/m. A prototype is constructed and the magnetic field is measured, demonstrating good agreement with the simulation. Particle track simulations provide initial values for the quadrupole positions. Accordingly, four PMQs are constructed and assembled on the beam line, their positions are then tuned to obtain a minimal beam spot size of (1.2 x 2.2) mm^2 on target. This paper describes an adjustable PMQ beam line for an external ion beam. The novel compact design based on commercially available NdFeB magnets allows high flexibility for ion beam applications.
Resumo:
This research examines the impact of relationship status on self-rated health (SRH) by taking into account intrapersonal and social resources. Data stem from a Swiss-based survey of 1355 participants aged 40-65 years. Three groups are compared: continuously married (n = 399), single divorcees (n = 532) and repartnered divorcees (n = 424). Linear regression models are used to examine the predictive role of relationship status on SRH and to investigate the moderating role of intrapersonal and social resources on SRH. Single divorcees show the lowest SRH scores, whereas their repartnered counterparts reported scores comparable to the continuously married – even after controlling for socio-demographic and economic variables. Although single divorcees reported higher levels of loneliness and agreeableness in addition to lower levels of resilience when compared with the other groups, none of these variables had a significant modification effect on SRH. Our results underscore the positive effect of relationship status on SRH, and contribute new insights on the impact of later-life divorce. Given the growing number of divorcees, related public health challenges are likely to increase.
Resumo:
Oscillations between high and low values of the membrane potential (UP and DOWN states respectively) are an ubiquitous feature of cortical neurons during slow wave sleep and anesthesia. Nevertheless, a surprisingly small number of quantitative studies have been conducted only that deal with this phenomenon’s implications for computation. Here we present a novel theory that explains on a detailed mathematical level the computational benefits of UP states. The theory is based on random sampling by means of interspike intervals (ISIs) of the exponential integrate and fire (EIF) model neuron, such that each spike is considered a sample, whose analog value corresponds to the spike’s preceding ISI. As we show, the EIF’s exponential sodium current, that kicks in when balancing a noisy membrane potential around values close to the firing threshold, leads to a particularly simple, approximative relationship between the neuron’s ISI distribution and input current. Approximation quality depends on the frequency spectrum of the current and is improved upon increasing the voltage baseline towards threshold. Thus, the conceptually simpler leaky integrate and fire neuron that is missing such an additional current boost performs consistently worse than the EIF and does not improve when voltage baseline is increased. For the EIF in contrast, the presented mechanism is particularly effective in the high-conductance regime, which is a hallmark feature of UP-states. Our theoretical results are confirmed by accompanying simulations, which were conducted for input currents of varying spectral composition. Moreover, we provide analytical estimations of the range of ISI distributions the EIF neuron can sample from at a given approximation level. Such samples may be considered by any algorithmic procedure that is based on random sampling, such as Markov Chain Monte Carlo or message-passing methods. Finally, we explain how spike-based random sampling relates to existing computational theories about UP states during slow wave sleep and present possible extensions of the model in the context of spike-frequency adaptation.
Resumo:
Objectives This research examines the impact of relationship status on self-rated health (SRH) by taking into account intrapersonal and social resources. Methods Data stem from a Swiss-based survey of 1355 participants aged 40–65 years. Three groups are compared: continuously married (n = 399), single divorcees (n = 532) and repartnered divorcees (n = 424). Linear regression models are used to examine the predictive role of relationship status on SRH and to investigate the moderating role of intrapersonal and social resources on SRH. Results Single divorcees show the lowest SRH scores, whereas their repartnered counterparts reported scores comparable to the continuously married—even after controlling for socio-demographic and economic variables. Although single divorcees reported higher levels of loneliness and agreeableness in addition to lower levels of resilience when compared with the other groups, none of these variables had a significant moderation effect on SRH. Conclusions Our results underscore the positive effect of relationship status on SRH, and contribute new insights on the impact of later-life divorce. Given the growing number of divorcees, related public health challenges are likely to increase.
Resumo:
STUDY QUESTION: What is the effect of the minimally invasive surgical treatment of endometriosis on health and on quality of work life (e.g. working performance) of affected women? SUMMARY ANSWER: Absence from work, performance loss and the general negative impact of endometriosis on the job are reduced significantly by the laparoscopic surgery. WHAT IS KNOWN ALREADY: The benefits of surgery overall and of the laparoscopic method in particular for treating endometriosis have been described before. However, previous studies focus on medical benchmarks without including the patient's perspective in a quantitative manner. STUDY DESIGN, SIZE, DURATION: A retrospective questionnaire-based survey covering 211 women with endometriosis and a history of specific laparoscopic surgery in a Swiss university hospital, tertiary care center. Data were returned anonymously and were collected from the beginning of 2012 until March 2013. PARTICIPANTS/MATERIALS, SETTING, METHODS: Women diagnosed with endometriosis and with at least one specific laparoscopic surgery in the past were enrolled in the study. The study investigated the effect of the minimally invasive surgery on health and on quality of work life of affected women. Questions used were obtained from the World Endometriosis Research Foundation (WERF) Global Study on Women's Health (GSWH) instrument. The questionnaire was shortened and adapted for the purpose of the present study. MAIN RESULTS AND THE ROLE OF CHANCE: Of the 587 women invited to participate in the study, 232 (232/587 = 40%) returned the questionnaires. Twenty-one questionnaires were excluded due to incomplete data and 211 sets (211/587 = 36%) were included in the study. Our data show that 62% (n = 130) of the study population declared endometriosis as influencing the job during the period prior to surgery, compared with 28% after surgery (P < 0.001). The mean (maximal) absence from work due to endometriosis was reduced from 2.0 (4.9) to 0.5 (1.4) hours per week (P < 0.001). The mean (maximal) loss in working performance after the surgery averaged out at 5.7% (12.6%) compared with 17.5% (30.5%) before this treatment (P < 0.001). LIMITATIONS, REASONS FOR CAUTION: The mediocre response rate of the study weakens the representativeness of the investigated population. Considering the anonymous setting a non-responder investigation was not performed. A bias due to selection, information and negativity effects within a retrospective survey cannot be excluded, although study-sensitive questions were provided in multiple ways. The absence of a control group (sham group; e.g. patients undergoing specific diagnostic laparoscopy without treatment) is a further limitation of the study. WIDER IMPLICATIONS OF THE FINDINGS: Our study shows that indicated minimally invasive surgery has a clear positive effect on the wellbeing and working performance of women suffering from moderate to severe endometriosis. Furthermore, national net savings in indirect costs with the present number of surgeries is estimated to be €10.7 million per year. In an idealized setting (i.e. without any diagnosis delay) this figure could be more than doubled. STUDY FUNDING/COMPETING INTERESTS: The study was performed on behalf of the University Hospital of Bern (Inselspital) as one of the leading Swiss tertiary care centers. The authors do not declare any competing interests.
Resumo:
AIMS Our aim was to report on a survey initiated by the European Association of Percutaneous Cardiovascular Interventions (EAPCI) collecting the opinion of the cardiology community on the invasive management of acute coronary syndrome (ACS), before and after the MATRIX trial presentation at the American College of Cardiology (ACC) 2015 Scientific Sessions. METHODS AND RESULTS A web-based survey was distributed to all individuals registered on the EuroIntervention mailing list (n=15,200). A total of 572 and 763 physicians responded to the pre- and post-ACC survey, respectively. The radial approach emerged as the preferable access site for ACS patients undergoing invasive management with roughly every other responder interpreting the evidence for mortality benefit as definitive and calling for a guidelines upgrade to class I. The most frequently preferred anticoagulant in ACS patients remains unfractionated heparin (UFH), due to higher costs and greater perceived thrombotic risks associated with bivalirudin. However, more than a quarter of participants declared the use of bivalirudin would increase after MATRIX. CONCLUSIONS The MATRIX trial reinforced the evidence for a causal association between bleeding and mortality and triggered consensus on the superiority of the radial versus femoral approach. The belief that bivalirudin mitigates bleeding risk is common, but UFH still remains the preferred anticoagulant based on lower costs and thrombotic risks.
Resumo:
AIMS Our aim was to report on a survey initiated by the European Association of Percutaneous Cardiovascular Interventions (EAPCI) concerning opinion on the evidence relating to dual antiplatelet therapy (DAPT) duration after coronary stenting. METHODS AND RESULTS Results from three randomised clinical trials were scheduled to be presented at the American Heart Association Scientific Sessions 2014 (AHA 2014). A web-based survey was distributed to all individuals registered in the EuroIntervention mailing list (n=15,200) both before and after AHA 2014. A total of 1,134 physicians responded to the first (i.e., before AHA 2014) and 542 to the second (i.e., after AHA 2014) survey. The majority of respondents interpreted trial results consistent with a substantial equipoise regarding the benefits and risks of an extended versus a standard DAPT strategy. Two respondents out of ten believed extended DAPT should be implemented in selected patients. After AHA 2014, 46.1% of participants expressed uncertainty about the available evidence on DAPT duration, and 40.0% the need for clinical guidance. CONCLUSIONS This EAPCI survey highlights considerable uncertainty within the medical community with regard to the optimal duration of DAPT after coronary stenting in the light of recent reported trial results. Updated recommendations for practising physicians to guide treatment decisions in routine clinical practice should be provided by international societies.
Resumo:
BACKGROUND Little is known about medical educators' self-definition. AIMS The aim of this study is to survey an international community of medical educators focusing on the medical educators' self-definition. METHODS Within a comprehensive, web-based survey, an open question on the participants' views of how they would define a "medical educator" was sent to 2200 persons on the mailing list of the Association for Medical Education in Europe. The free text definitions were analysed using qualitative thematic analysis. RESULTS Of the, 200 medical educators invited to participate, 685 (31.1%) provided a definition of a "medical educator". The qualitative analysis of the free text definitions revealed that medical educators defined themselves in 13 roles, primarily as "Professional Expert", "Facilitator", "Information Provider", "Enthusiast", "Faculty Developer", "Mentor", "Undergraduate and Postgraduate Trainer", "Curriculum Developer", "Assessor and Assessment Creator", and "Researcher". CONCLUSIONS Our survey revealed that medical educators predominantly define themselves as "Professional Experts" and identified 12 further self-defined roles of a medical educator, several of which not to have been reported previously. The results can be used to further the understanding of our professional identity.
Resumo:
BACKGROUND Uncertainty about the presence of infection results in unnecessary and prolonged empiric antibiotic treatment of newborns at risk for early-onset sepsis (EOS). This study evaluates the impact of this uncertainty on the diversity in management. METHODS A web-based survey with questions addressing management of infection risk-adjusted scenarios was performed in Europe, North America, and Australia. Published national guidelines (n=5) were reviewed and compared to the results of the survey. RESULTS 439 Clinicians (68% were neonatologists) from 16 countries completed the survey. In the low-risk scenario, 29% would start antibiotic therapy and 26% would not, both groups without laboratory investigations; 45% would start if laboratory markers were abnormal. In the high-risk scenario, 99% would start antibiotic therapy. In the low-risk scenario, 89% would discontinue antibiotic therapy before 72 hours. In the high-risk scenario, 35% would discontinue therapy before 72 hours, 56% would continue therapy for five to seven days, and 9% for more than 7 days. Laboratory investigations were used in 31% of scenarios for the decision to start, and in 72% for the decision to discontinue antibiotic treatment. National guidelines differ considerably regarding the decision to start in low-risk and regarding the decision to continue therapy in higher risk situations. CONCLUSIONS There is a broad diversity of clinical practice in management of EOS and a lack of agreement between current guidelines. The results of the survey reflect the diversity of national guidelines. Prospective studies regarding management of neonates at risk of EOS with safety endpoints are needed.
Resumo:
The impact of nanoparticles (NPs) in medicine and biology has increased rapidly in recent years. Gold NPs have advantageous properties such as chemical stability, high electron density and affinity to biomolecules, making them very promising candidates as drug carriers and diagnostic tools. However, diverse studies on the toxicity of gold NPs have reported contradictory results. To address this issue, a triple cell co-culture model simulating the alveolar lung epithelium was used and exposed at the air-liquid interface. The cell cultures were exposed to characterized aerosols with 15 nm gold particles (61 ng Au/cm2 and 561 ng Au/cm2 deposition) and incubated for 4 h and 24 h. Experiments were repeated six times. The mRNA induction of pro-inflammatory (TNFalpha, IL-8, iNOS) and oxidative stress markers (HO-1, SOD2) was measured, as well as protein induction of pro- and anti-inflammatory cytokines (IL-1, IL-2, IL-4, IL-6, IL-8, IL-10, GM-CSF, TNFalpha, INFgamma). A pre-stimulation with lipopolysaccharide (LPS) was performed to further study the effects of particles under inflammatory conditions. Particle deposition and particle uptake by cells were analyzed by transmission electron microscopy and design-based stereology. A homogeneous deposition was revealed, and particles were found to enter all cell types. No mRNA induction due to particles was observed for all markers. The cell culture system was sensitive to LPS but gold particles did not cause any synergistic or suppressive effects. With this experimental setup, reflecting the physiological conditions more precisely, no adverse effects from gold NPs were observed. However, chronic studies under in vivo conditions are needed to entirely exclude adverse effects.
Resumo:
Glycan-binding antibodies form a significant subpopulation of both natural and acquired antibodies and play an important role in various immune processes. They are for example involved in innate immune responses, cancer, autoimmune diseases, and neurological disorders. In the present study, a microsphere-based flow-cytometric immunoassay (suspension array) was applied for multiplexed detection of glycan-binding antibodies in human serum. Several approaches for immobilization of glycoconjugates onto commercially available fluorescent microspheres were compared, and as the result, the design based on coupling of end-biotinylated glycopolymers has been selected. This method requires only minute amounts of glycans, similar to a printed glycan microarray. The resulting glyco-microspheres were used for detection of IgM and IgG antibodies directed against ABO blood group antigens. The possibility of multiplexing this assay was demonstrated with mixtures of microspheres modified with six different ABO related glycans. Multiplexed detection of anti-glycan IgM and IgG correlated well with singleplex assays (Pearson's correlation coefficient r = 0.95-0.99 for sera of different blood groups). The suspension array in singleplex format for A/B trisaccharide, H(di) and Le(x) microspheres corresponded well to the standard ELISA (r > 0.94). Therefore, the described method is promising for rapid, sensitive, and reproducible detection of anti-glycan antibodies in a multiplexed format.
Resumo:
Content-centric networking is a novel paradigm for the Future Internet that treats content as a first class citizen. This paper argues that content-centric networking should be generalized towards a service-centric networking scheme. We propose a service-centric networking design based on an object-oriented approach, in which content and services are considered objects. We show implementation architectures for example services and how these can benefit from service-oriented networking.
Resumo:
Hepatocyte growth factor (HGF) is involved in development and regeneration of the lungs. Human HGF, which was expressed specifically by alveolar epithelial type II cells after gene transfer, attenuated the bleomycin-induced pulmonary fibrosis in an animal model. As there are also regions that appear morphologically unaffected in fibrosis, the effects of this gene transfer to normal lungs is of interest. In vitro studies showed that HGF inhibits the formation of the basal lamina by cultured alveolar epithelial cells. Thus we hypothesized that, in the healthy lung, cell-specific expression of HGF induces a remodeling within septal walls. Electroporation of a plasmid of human HGF gene controlled by the surfactant protein C promoter was applied for targeted gene transfer. Using design-based stereology at light and electron microscopic level, structural alterations were analyzed and compared with a control group. HGF gene transfer increased the volume of distal air spaces, as well as the surface area of the alveolar epithelium. The volume of septal walls, as well as the number of alveoli, was unchanged. Volumes per lung of collagen and elastic fibers were unaltered, but a marked reduction of the volume of residual extracellular matrix (all components other than collagen and elastic fibers) and interstitial cells was found. A correlation between the volumes of residual extracellular matrix and distal air spaces, as well as total surface area of alveolar epithelium, could be established. Cell-specific expression of HGF leads to a remodeling of the connective tissue within the septal walls in the healthy lung, which is associated with more pronounced stretching of distal air spaces at a given hydrostatic pressure during instillation fixation.
Resumo:
OBJECTIVE: To describe and evaluate psychosocial factors in nonorganic voice disorders (NVDs). Nonorganic voice disorders are presumed to be the result of increased muscular tension that is caused to varying extents by vocal misuse and emotional stress. It is therefore necessary to include both of these in the diagnosis and treatment of patients with voice disorders. DESIGN: Clinical survey. SETTING: Academic tertiary referral center. PATIENTS: To evaluate psychosocial factors in NVDs, a sample of 74 patients with NVDs was examined psychologically using the Giessen Test and Picture Frustration Test. The results were compared with a control group of 19 patients with an organic dysphonia (vocal cord paralysis). MAIN OUTCOME MEASURES: Six scales of the Giessen Test (social response, dominance, control, underlying mood, permeability, and social potency), 3 reaction types of the Picture Frustration Test (obstacle dominance, ego defense, and need persistence), and 3 aggression categories of the Picture Frustration Test (extrapunitivity, intropunitivity, and impunitivity). RESULTS: The most striking significant difference between the 2 groups was that in conflict situations, patients with NVDs sought a quick solution or expected other people to provide one, which prevented them from understanding the underlying causes of the conflict. CONCLUSIONS: Only if the psychosocial aspects are taken into account can patients with NVD be offered a therapy that treats the causes of the voice disorder. It must be decided individually whether and when a voice training approach or a more psychological-psychotherapeutical approach is preferable.