124 research outputs found

    Quantitative EEG (QEEG) Measures Differentiate Parkinson`s Disease Patients from Healthy Controls

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    Objectives: To find out which Quantitative EEG (QEEG) parameters could best distinguish patients with Parkinson's disease (PD) with and without Mild Cognitive Impairment from healthy individuals and to find an optimal method for feature selection. Background: Certain QEEG parameters have been seen to be associated with dementia in Parkinson's and Alzheimer's disease. Studies have also shown some parameters to be dependent on the stage of the disease. We wanted to investigate the differences in high-resolution QEEG measures between groups of PD patients and healthy individuals, and come up with a small subset of features that could accurately distinguish between the two groups. Methods: High-resolution 256-channel EEG were recorded in 50 PD patients (age 68.8 ± 7.0 year; female/male 17/33) and 41 healthy controls (age 71.1 ± 7.7 year; female/male 20/22). Data was processed to calculate the relative power in alpha, theta, delta, beta frequency bands across the different regions of the brain. Median, peak frequencies were also obtained and alpha1/theta ratios were calculated. Machine learning methods were applied to the data and compared. Additionally, penalized Logistic regression using LASSO was applied to the data in R and a subset of best-performing features was obtained. Results: Random Forest and LASSO were found to be optimal methods for feature selection. A group of six measures selected by LASSO was seen to have the most effect in differentiating healthy individuals from PD patients. The most important variables were the theta power in temporal left region and the alpha1/theta ratio in the central left region. Conclusion: The penalized regression method applied was helpful in selecting a small group of features from a dataset that had high multicollinearity. Keywords: Parkinson's disease, QEEG, cognitive decline, Parkinson's disease dementia, neurodegenerative disorders, machine learnin

    Fast 2D/3D object representation with growing neural gas

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    This work presents the design of a real-time system to model visual objects with the use of self-organising networks. The architecture of the system addresses multiple computer vision tasks such as image segmentation, optimal parameter estimation and object representation. We first develop a framework for building non-rigid shapes using the growth mechanism of the self-organising maps, and then we define an optimal number of nodes without overfitting or underfitting the network based on the knowledge obtained from information-theoretic considerations. We present experimental results for hands and faces, and we quantitatively evaluate the matching capabilities of the proposed method with the topographic product. The proposed method is easily extensible to 3D objects, as it offers similar features for efficient mesh reconstruction

    Dynamic Power Management for Reactive Stream Processing on the SCC Tiled Architecture

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    This article is distributed under the terms of the Creative Commons Attribution 4.0 International License(http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.Dynamic voltage and frequency scaling} (DVFS) is a means to adjust the computing capacity and power consumption of computing systems to the application demands. DVFS is generally useful to provide a compromise between computing demands and power consumption, especially in the areas of resource-constrained computing systems. Many modern processors support some form of DVFS. In this article we focus on the development of an execution framework that provides light-weight DVFS support for reactive stream-processing systems (RSPS). RSPS are a common form of embedded control systems, operating in direct response to inputs from their environment. At the execution framework we focus on support for many-core scheduling for parallel execution of concurrent programs. We provide a DVFS strategy for RSPS that is simple and lightweight, to be used for dynamic adaptation of the power consumption at runtime. The simplicity of the DVFS strategy became possible by sole focus on the application domain of RSPS. The presented DVFS strategy does not require specific assumptions about the message arrival rate or the underlying scheduling method. While DVFS is a very active field, in contrast to most existing research, our approach works also for platforms like many-core processors, where the power settings typically cannot be controlled individually for each computational unit. We also support dynamic scheduling with variable workload. While many research results are provided with simulators, in our approach we present a parallel execution framework with experiments conducted on real hardware, using the SCC many-core processor. The results of our experimental evaluation confirm that our simple DVFS strategy provides potential for significant energy saving on RSPS.Peer reviewe

    The Organic Food Premium: A Local Assessment in the UK

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    The present study combines stated and revealed preferences in order to estimate the hypothetical bias of a sample of organic food consumers from Canterbury in the UK. It uses contingent valuation and hedonic pricing to compare stated and revealed preferences and employs the Almost Ideal Demand System to estimate the elasticity of organic products. The results show that the average price premium is fairly large (approximately 10%). They also demonstrate, crucially, that the size of this estimate is encouragingly similar whether a willingness-to-pay or hedonic pricing method is used. The estimated elasticity of organic products is on average above one, suggesting an elastic response to pricing policy in the present sample. Desirable next steps and potential policy applications for future research are also discussed

    Vorhersage von Psychosen durch stufenweise Mehrebenenabklärung - Das Basel FePsy (Früherkennung von Psychosen)-Projekt

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    Hintergrund: In Basel haben wir verschiedene Studien zur Verbesserung der Methodik zur Früherkennung von Psychosen (FePsy) durchgeführt. Methodik: Vom 01.03.2000 bis 29.02.2004 wurden 234 Individuen mithilfe des Basler Screening Instruments für Psychosen (BSIP) gescreent. Bei 10 6 Patienten konnte ein Risikostatus für Psychosen diagnostiziert werden, 53 davon konnten bis zu 7 Jahre (Mittel 5. 4 Jahre) nachuntersucht werden. Die weiteren Untersuchungen erfolgten u.a. mit einem spezifisch entwickelten Anamnese - Instrument, verschiedenen Skalen zur Psychopathologie, Untersuchungen der Neuropsychologie u n d Feinmotorik , klinische m und quantitative m EEG, MRI des Gehirns, Labor. Ergebnisse: Allein auf der Basis des BSIP konnte eine relativ zuverlässige Vorher sage getroffen werden: 21 (39.6 % ) der als „ Risikopatienten “Identifizierten entwickelten innerhalb der Beobachtungszeit tatsächlich eine Psychose. Post hoc konnte durch spezifischere Gewichtung der Psychopathologie und Einbezug neuropsychologischer Untersuchungen die Vorhersagegenauigkeit auf 81 % gesteigert werden. Die anderen oben genannten Verfahren können offensichtlich zur weiteren Verbesserung der Prädiktion beitragen. Schlussfolgerungen: Die Risikoabklärung für Psychose sollte stufenweise und unter Einbezug verschiedener Untersuchungsebenen erfolgen. Background: We have conducted various studies in Basel with the aim of improving the methods for the early detection of psychosis (Fruherkennung von Psychosen, FePsy).Methods: From 1.3.2000 to 29.2.2004 234 individuals were screened using the Basel Screening Instrument for Psychosis (BSIP). 106 patients were identified as at risk for psychosis; out of these 53 remained in follow-up for up to 7 years (mean 5.4 years). The assessments were done with a specifically developed instrument for history taking, various scales for the psychopathology, assessments of neuropsychology and fine motor functioning, clinical and quantitative EEG, MRI of the brain, laboratory etc.Results: Based on the BSIP alone, a relatively reliable prediction was possible: 21 (39.6 %) of the individuals identified as at risk developed psychosis within the follow-up time. Post-hoc prediction could be improved to 81 % by weighting psychopathology and including neuropsychology. Including the other domains obviously allows further improvements of prediction.Conclusions: The risk for psychosis should be assessed in a stepwise procedure. In a first step, a clinically oriented screening should be conducted. If an at-risk status is found, further assessments in various domains should be done in a specialised centre

    Guidance for the Management of Patients with Vascular Disease or Cardiovascular Risk Factors and COVID-19: Position Paper from VAS-European Independent Foundation in Angiology/Vascular Medicine .

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    COVID-19 is also manifested with hypercoagulability, pulmonary intravascular coagulation, microangiopathy, and venous thromboembolism (VTE) or arterial thrombosis. Predisposing risk factors to severe COVID-19 are male sex, underlying cardiovascular disease, or cardiovascular risk factors including noncontrolled diabetes mellitus or arterial hypertension, obesity, and advanced age. The VAS-European Independent Foundation in Angiology/Vascular Medicine draws attention to patients with vascular disease (VD) and presents an integral strategy for the management of patients with VD or cardiovascular risk factors (VD-CVR) and COVID-19. VAS recommends (1) a COVID-19-oriented primary health care network for patients with VD-CVR for identification of patients with VD-CVR in the community and patients' education for disease symptoms, use of eHealth technology, adherence to the antithrombotic and vascular regulating treatments, and (2) close medical follow-up for efficacious control of VD progression and prompt application of physical and social distancing measures in case of new epidemic waves. For patients with VD-CVR who receive home treatment for COVID-19, VAS recommends assessment for (1) disease worsening risk and prioritized hospitalization of those at high risk and (2) VTE risk assessment and thromboprophylaxis with rivaroxaban, betrixaban, or low-molecular-weight heparin (LMWH) for those at high risk. For hospitalized patients with VD-CVR and COVID-19, VAS recommends (1) routine thromboprophylaxis with weight-adjusted intermediate doses of LMWH (unless contraindication); (2) LMWH as the drug of choice over unfractionated heparin or direct oral anticoagulants for the treatment of VTE or hypercoagulability; (3) careful evaluation of the risk for disease worsening and prompt application of targeted antiviral or convalescence treatments; (4) monitoring of D-dimer for optimization of the antithrombotic treatment; and (5) evaluation of the risk of VTE before hospital discharge using the IMPROVE-D-dimer score and prolonged post-discharge thromboprophylaxis with rivaroxaban, betrixaban, or LMWH

    Exploring Predictors of Outcome in the Psychosis Prodrome: Implications for Early Identification and Intervention

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    Functional disability is a key component of many psychiatric illnesses, particularly schizophrenia. Impairments in social and role functioning are linked to cognitive deficits, a core feature of psychosis. Retrospective analyses demonstrate that substantial functional decline precedes the onset of psychosis. Recent investigations reveal that individuals at clinical-high-risk (CHR) for psychosis show impairments in social relationships, work/school functioning and daily living skills. CHR youth also demonstrate a pattern of impairment across a range of cognitive domains, including social cognition, which is qualitatively similar to that of individuals with schizophrenia. While many studies have sought to elucidate predictors of clinical deterioration, specifically the development of schizophrenia, in such CHR samples, few have investigated factors relevant to psychosocial outcome. This review integrates recent findings regarding cognitive and social-cognitive predictors of outcome in CHR individuals, and proposes potential directions for future research that will contribute to targeted interventions and improved outcome for at-risk youth

    Extensive use of peripheral angioplasty, particularly infrapopliteal, in the treatment of ischaemic diabetic foot ulcers : clinical results of a multicentric study of 221 consecutive diabetic subjects

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    OBJECTIVE: To evaluate the feasibility, technical effectiveness and limb salvage potential of percutaneous transluminal angioplasty (PTA), particularly infrapopliteal, in diabetic subjects with ischaemic foot ulcer. DESIGN: Intervention study with PTA in consecutive series. SETTING: Six Diabetology Foot Centres and one Cardiovascular Catheterization Laboratory in Italy. SUBJECTS: Two hundred and twenty-one consecutive diabetic subjects hospitalized for ischaemic foot ulcer. INTERVENTION: Peripheral arterial occlusive disease (PAOD) was investigated by means of foot pulses assessment, ankle-brachial-index (ABI), transcutaneous oxygen tension (TcPO2) and duplex scanning. If non-invasive parameters suggested PAOD, angiography was performed and a PTA was carried out during the same session. MAIN OUTCOME MEASURES: PTA feasibility, improvement of ABI and TcPO2, limb salvage rate, clinical recurrence. RESULTS: On angiography, two patients had stenoses which were 50%, even when longer than 10 cm and/or multiple/calcified. In 11 patients (5.8%) PTA was performed in the proximal axis exclusively, in 81 (42.4%) patients in the infrapopliteal axis exclusively and in 99 (51.8%) in both the femoropopliteal and infrapopliteal axis. Both ABI and TcPO2 improved significantly after PTA (P < 0.0001). Clinical recurrence occurred in 14 subjects: 10 of whom underwent a second successful PTA. Of the 191 patients who underwent PTA, 10 (5.2%) underwent an above-the-ankle amputation. CONCLUSIONS: PTA, including infrapopliteal, is feasible in most diabetic subjects with ischaemic foot ulcer and is effective for foot revascularization. Clinical recurrence was infrequent and the procedure could successfully be repeated in most cases. In subjects treated successfully with PTA the above-the-ankle amputation rate was low. PTA should be considered as the revascularization treatment of first choice in all diabetic subjects with foot ulcer and PAOD
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