Quantizations on the circle and coherent states

We present a possible construction of coherent states on the unit circle as configuration space. Our approach is based on Borel quantizations on S^1 including the Aharonov-Bohm type quantum description. The coherent states are constructed by Perelomov's method as group related coherent states generated by Weyl operators on the quantum phase space Z x S^1. Because of the duality of canonical coordinates and momenta, i.e. the angular variable and the integers, this formulation can also be interpreted as coherent states over an infinite periodic chain. For the construction we use the analogy with our quantization and coherent states over a finite periodic chain where the quantum phase space was Z_M x Z_M. The coherent states constructed in this work are shown to satisfy the resolution of unity. To compare them with canonical coherent states, also some of their further properties are studied demonstrating similarities as well as substantial differences.Comment: 15 pages, 4 figures, accepted in J. Phys. A: Math. Theor. 45 (2012) for the Special issue on coherent states: mathematical and physical aspect

Risk Factors for Hospital Malpractice Exposure: Implications for Managers and Insurers

The possibility of identifying certain variables that might serve as predictors of above- or below-average medical malpractice claims experience was explored. Results showed that it is possible to identify significant risk factors

Coherent states on the circle

We present a possible construction of coherent states on the unit circle as configuration space. In our approach the phase space is the product Z x S^1. Because of the duality of canonical coordinates and momenta, i.e. the angular variable and the integers, this formulation can also be interpreted as coherent states over an infinite periodic chain. For the construction we use the analogy with our quantization over a finite periodic chain where the phase space was Z_M x Z_M. Properties of the coherent states constructed in this way are studied and the coherent states are shown to satisfy the resolution of unity.Comment: 7 pages, presented at GROUP28 - "28th International Colloquium on Group Theoretical Methods in Physics", Newcastle upon Tyne, July 2010. Accepted in Journal of Physics Conference Serie

Gene silencing and a novel monoallelic expression pattern in distinct CD177 neutrophil subsets

CD177 presents antigens in allo- and autoimmune diseases on the neutrophil surface. Individuals can be either CD177-deficient or harbor distinct CD177(neg) and CD177(pos) neutrophil subsets. We studied mechanisms controlling subset-restricted CD177 expression in bimodal individuals. CD177(pos), but not CD177(neg) neutrophils, produced CD177 protein and mRNA. Haplotype analysis indicated a unique monoallelic CD177 expression pattern, where the offspring stably transcribed either the maternal or paternal allele. Hematopoietic stem cells expressed both CD177 alleles and silenced one copy during neutrophil differentiation. ChIP and reporter assays in HeLa cells with monoallelic CD177 expression showed that methylation reduced reporter activity, whereas demethylation caused biallelic CD177 expression. HeLa cell transfection with c-Jun and c-Fos increased CD177 mRNA. Importantly, CD177(pos) human neutrophils, but not CD177(neg) neutrophils, showed a euchromatic CD177 promoter, unmethylated CpGs, and c-Jun and c-Fos binding. We describe epigenetic mechanisms explaining the two distinct CD177 neutrophil subsets and a novel monoallelic CD177 expression pattern that does not follow classical random monoallelic expression or imprinting

Classifying Cognitive Profiles Using Machine Learning with Privileged Information in Mild Cognitive Impairment

Early diagnosis of dementia is critical for assessing disease progression and potential treatment. State-or-the-art machine learning techniques have been increasingly employed to take on this diagnostic task. In this study, we employed Generalized Matrix Learning Vector Quantization (GMLVQ) classifiers to discriminate patients with Mild Cognitive Impairment (MCI) from healthy controls based on their cognitive skills. Further, we adopted a "Learning with privileged information" approach to combine cognitive and fMRI data for the classification task. The resulting classifier operates solely on the cognitive data while it incorporates the fMRI data as privileged information (PI) during training. This novel classifier is of practical use as the collection of brain imaging data is not always possible with patients and older participants. MCI patients and healthy age-matched controls were trained to extract structure from temporal sequences. We ask whether machine learning classifiers can be used to discriminate patients from controls and whether differences between these groups relate to individual cognitive profiles. To this end, we tested participants in four cognitive tasks: working memory, cognitive inhibition, divided attention, and selective attention. We also collected fMRI data before and after training on a probabilistic sequence learning task and extracted fMRI responses and connectivity as features for machine learning classifiers. Our results show that the PI guided GMLVQ classifiers outperform the baseline classifier that only used the cognitive data. In addition, we found that for the baseline classifier, divided attention is the only relevant cognitive feature. When PI was incorporated, divided attention remained the most relevant feature while cognitive inhibition became also relevant for the task. Interestingly, this analysis for the fMRI GMLVQ classifier suggests that (1) when overall fMRI signal is used as inputs to the classifier, the post-training session is most relevant; and (2) when the graph feature reflecting underlying spatiotemporal fMRI pattern is used, the pre-training session is most relevant. Taken together these results suggest that brain connectivity before training and overall fMRI signal after training are both diagnostic of cognitive skills in MCI.PT and YS were supported by EPSRC grant no EP/L000296/1 “Personalized Medicine through Learning in the Model Space.” This work was supported by grants to ZK from the Biotechnology and Biological Sciences Research Council (H012508), the Leverhulme Trust (RF-2011-378), and the (European Community's) Seventh Framework Programme (FP7/2007-2013) under agreement PITN-GA-2011-290011

External Validation of the Early Prediction of Functional Outcome After Stroke Prediction Model for Independent Gait at 3 Months After Stroke

INTRODUCTION: The Early Prediction of Functional Outcome after Stroke (EPOS) model for independent gait is a tool to predict between days 2 and 9 poststroke whether patients will regain independent gait 6 months after stroke. External validation of the model is important to determine its clinical applicability and generalizability by testing its performance in an independent cohort. Therefore, this study aimed to perform a temporal and geographical external validation of the EPOS prediction model for independent gait after stroke but with the endpoint being 3 months instead of the original 6 months poststroke. METHODS: Two prospective longitudinal cohort studies consisting of patients with first-ever stroke admitted to a Swiss hospital stroke unit. Sitting balance and strength of the paretic leg were tested at days 1 and 8 post-stroke in Cohort I and at days 3 and 9 in Cohort II. Independent gait was assessed 3 months after symptom onset. The performance of the model in terms of discrimination (area under the receiver operator characteristic (ROC) curve; AUC), classification, and calibration was assessed. RESULTS: In Cohort I [N = 39, median age: 74 years, 33% women, median National Institutes of Health Stroke Scale (NIHSS) 9], the AUC (95% confidence interval (CI)] was 0.675 (0.510, 0.841) on day 1 and 0.921 (0.811, 1.000) on day 8. For Cohort II (N = 78, median age: 69 years, 37% women, median NIHSS 8), this was 0.801 (0.684, 0.918) on day 3 and 0.846 (0.741, 0.951) on day 9. DISCUSSION AND CONCLUSION: External validation of the EPOS prediction model for independent gait 3 months after stroke resulted in an acceptable performance from day 3 onward in mild-to-moderately affected patients with first-ever stroke without severe prestroke disability. The impact of applying this model in clinical practice should be investigated within this subgroup of patients with stroke. To improve the generalizability of patients with recurrent stroke and those with more severe, neurological comorbidities, the performance of the EPOS model within these patients should be determined across different geographical areas

Schlaganfall aus der Perspektive des Neurologen (Teil 3): Neues in der Sekundärprävention

In dieser dritten Ausgabe über den Schlaganfall wird die Sekundärprävention besprochen. Nach der Akutphase mit ihren Massnahmen zur Wiedereröffnung eines verschlossenen Hirngefässes schenkt man der Prävention eines erneuten Schlaganfalls und wenn möglich der Frührehabilitation die volle Aufmerksamkeit. Aus der Perspektive des Neurologen ist eine systematische Diagnostik, eine erweiterte Abklärung der (nicht-)modifizierbaren Risikofaktoren und eine mit der Klinik und Bildgebung integrierte präventive Therapie dringend erforderlich. Neben der optimalen Einstellung der wichtigen therapierbaren Risikofaktoren wie arterielle Hypertonie, Vorhofflimmern, Diabetes mellitus und Dyslipidämie sind auch die Behandlung des obstruktiven Schlafapnoe-Syndroms und komplexer Atheromatosen (komplexe Plaque der Aorta >4 mm [1]) als eigenständige Risikofaktoren erwiesen. Die Suche nach der Ätiologie geht meist nach der Definition der Wahrscheinlichkeit verschiedener Ursachen. Die wahrscheinlichste wird dann als Ursache angenommen. Nur in seltenen Fällen findet sich keine Ursache. Dann kann das Läsionsmuster helfen, zumindest zwischen embolischem und thrombotischem Ereignis zu unterscheiden. In this third edition the secondary prevention of stroke will be discussed. After the acute phase in which recanalization of an occluded brain artery is in the focus, the risks for a recurrent stroke have to be minimized and rehabilitation should be started. A systematic workup, an extended evaluation of (non-) modifiable risk factors and the clinical-radiological findings are the source of an effective preventive therapy. Risk assessment of the major risk factors such as arterial hypertension, atrial fibrillation, diabetes and dyslipidemia is established. The obstructive sleep apnea syndrome and the complex atheromatosis with a complex structure are independent risk factors for stroke. The search for an etiology is usually a definition of probabilities. The most probable cause of stroke is assumed