71 research outputs found
Particles with anomalous magnetic moment in external e.m. fields: the proper time formulation
In this paper we evaluate the expression for the Green function of a
pseudo-classical spinning particle interacting with constant electromagnetic
external fields by taking into account the anomalous magnetic and electric
moments of the particle. The spin degrees of freedom are described in terms of
Grassmann variables and the evolution operator is obtained through the
Fock-Schwinger proper time method.Comment: 10 page
Intelligent Health Monitoring of Machine Bearings Based on Feature Extraction
This document is the Accepted Manuscript of the following article: Mohammed Chalouli, Nasr-eddine Berrached, and Mouloud Denai, ‘Intelligent Health Monitoring of Machine Bearings Based on Feature Extraction’, Journal of Failure Analysis and Prevention, Vol. 17 (5): 1053-1066, October 2017. Under embargo. Embargo end date: 31 August 2018. The final publication is available at Springer via DOI: https://doi.org/10.1007/s11668-017-0343-y.Finding reliable condition monitoring solutions for large-scale complex systems is currently a major challenge in industrial research. Since fault diagnosis is directly related to the features of a system, there have been many research studies aimed to develop methods for the selection of the relevant features. Moreover, there are no universal features for a particular application domain such as machine diagnosis. For example, in machine bearing fault diagnosis, these features are often selected by an expert or based on previous experience. Thus, for each bearing machine type, the relevant features must be selected. This paper attempts to solve the problem of relevant features identification by building an automatic fault diagnosis process based on relevant feature selection using a data-driven approach. The proposed approach starts with the extraction of the time-domain features from the input signals. Then, a feature reduction algorithm based on cross-correlation filter is applied to reduce the time and cost of the processing. Unsupervised learning mechanism using K-means++ selects the relevant fault features based on the squared Euclidian distance between different health states. Finally, the selected features are used as inputs to a self-organizing map producing our health indicator. The proposed method is tested on roller bearing benchmark datasets.Peer reviewe
Duodenal carcinoma at the ligament of Treitz. A molecular and clinical perspective
Background
There is very small occurrence of adenocarcinoma in the small bowel. We present a case of primary duodenal adenocarcinoma and discuss the findings of the case diagnostic modalities, current knowledge on the molecular biology behind small bowel neoplasms and treatment options.
Case
The patient had a history of iron deficiency anemia and occult bleeding with extensive workup consisting of upper endoscopy, colonoscopy, capsule endoscopy, upper gastrointestinal series with small bowel follow through and push enteroscopy. Due to persistent abdominal pain and iron deficiency anemia the patient underwent push enteroscopy which revealed adenocarcinoma of the duodenum. The patient underwent en-bloc duodenectomy which revealed T3N1M0 adenocarcinoma of the 4th portion of the duodenum.
Conclusions
Primary duodenal carcinoma, although rare should be considered in the differential diagnosis of occult gastrointestinal bleeding when evaluation of the lower and upper GI tract is unremarkable. We discuss the current evaluation and management of this small bowel neoplasm
Functional MRI evidence for the decline of word retrieval and generation during normal aging
International audienceThis fMRI study aimed to explore the effect of normal aging on word retrieval and generation. The question addressed is whether lexical production decline is determined by a direct mechanism, which concerns the language operations or is rather indirectly induced by a decline of executive functions. Indeed, the main hypothesis was that normal aging does not induce loss of lexical knowledge, but there is only a general slowdown in retrieval mechanisms involved in lexical processing , due to possible decline of the executive functions. We used three tasks (verbal fluency, object naming , and semantic categorization). Two groups of participants were tested (Young, Y and Aged, A), without cognitive and psychiatric impairment and showing similar levels of vocabulary. Neuropsychological testing revealed that older participants had lower executive function scores, longer processing speeds, and tended to have lower verbal fluency scores. Additionally, older participants showed higher scores for verbal automa-tisms and overlearned information. In terms of behav-ioral data, older participants performed as accurate as younger adults, but they were significantly slower for the semantic categorization and were less fluent for verbal fluency task. Functional MRI analyses suggested that older adults did not simply activate fewer brain regions involved in word production, but they actually showed an atypical pattern of activation. Significant correlations between the BOLD (Blood Oxygen Level Dependent) signal of aging-related (A > Y) regions and cognitive scores suggested that this atypical pattern of the activation may reveal several compensatory mechanisms (a) to overcome the slowdown in retrieval, due to the decline of executive functions and processing speed and (b) to inhibit verbal automatic processes. The BOLD signal measured in some other aging-dependent regions did not correlate with the behavioral and neuro-psychological scores, and the overactivation of these uncorrelated regions would simply reveal dedifferentia-tion that occurs with aging. Altogether, our results suggest that normal aging is associated with a more difficult access to lexico-semantic operations and representations by a slowdown in executive functions, without any conceptual loss
Real-time diagnosis of three-phase induction machine using Arduino-Uno card based on Park’s circle method
The main role of diagnosis is the real-time detection of the different types of faults on the physical system. Induction motors are nowadays used more frequently than any other electric motor in various kinds of electric drives. Incipient fault diagnosis is very important because if the fault is undetected, small motor failure can lead to serious motor failure. The objective of this work is the study and the realization of a diagnosis based on signal processing by the Park method of a wound rotor induction machine (in real-time). We have chosen for the realization of this diagnostic strategy the Arduino-UNO board and the ACS-720 current sensor as a signal acquisition system. The results obtained in practice show that this method of diagnosis is a very powerful and very sensitive technique for signaling and identifying the different types of faults and achieving the desired objectives
Procédures interventionnelles percutanées abdominales et pelviennes sous contrôle TDM à l’aide d’un système de guidage fluoroscopique intégré à 21 mA : analyse de 99 cas
Revista Portuguesa de Órgão Oficial da Sociedade Portuguesa de Cirurgia Intra-operative cholangiography is not necessary in avoiding bile duct injury (ten years review) Colangiografia intraoperatória não é necessária para evitar lesões da via biliar (revi
RESUMO A discussão acerca da colangiografia peroperatória (CPO) de rotina durante a colecistectomia laparoscópica (CL) continua ainda em aberto. As lesões da via biliar principal continuam a ser a principal complicação deste procedimento. A questão é: como evitar a mais temida complicação da CL? Os autores relatam um estudo retrospectivo de 1111 CL executadas no seu departamento nos últimos dez anos. A CPO não foi feita na maior parte dos casos devido à realização pré-operatória de ecografias e colangioRMN. Obtiveram bons resultados técnicos apesar disso. Por isso, a sua experiência permite-lhes afirmar que aquele exame radiológico não é necessário durante a intervenção cirúrgica na maior parte dos doentes com cálculos biliares. Palavras chave: lesões da via biliar, colecistectomia laparoscópica, prevenção ABSTRACT The debate about routine intra-operative cholangiography (IOC) during laparoscopic cholecystectomy (LC) is still open. Bile duct injuries remain the main complication of this procedure. The question is: how to avoid the most feared complication of LC? The authors report a retrospective study of 1111 LC underwent in their department the last ten years. IOC wasn't done in most cases due to pre operative performances of ultrasound and bili-MRI. Their own technique has given them good results despite this. Their experience allows them to declare that this x-ray exam is not necessary during the procedure in most of patients presenting gallstone disease
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