88 research outputs found

    Preliminary results of a paleoseismological analysis along the Sahel fault (Algeria): New evidence for historical seismic events

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    International audienceThe ∼60 km-long Sahel ridge west of Algiers (Tell Atlas, north Algeria) is considered as an ENE-WSW fault-propagation fold running along the Mediterranean coast and associated with a north-west dipping thrust. Its proximity with Algiers makes this structure a potential source of destructive earthquakes that could hit the capital city, as occurred in 1365 AD and 1716 AD. The first paleoseismologic investigation on the Sahel ridge was conducted in order to detect paleo-ruptures related to active faulting and to date them. From the first investigations in the area, a first trench was excavated across bending-moment normal faults induced by flexural slip folding in the hanging wall of the Sahel anticline thrust ramp. Paleoseismological analyses recognize eight rupture events affecting colluvial deposits. 14C dating indicates that these events are very young, six of them being younger than 778 AD. The first sedimentary record indicates two ruptures before 1211 AD, i.e. older than the first historical earthquake documented in the region. Three events have age ranges compatible with the 1365, 1673 and 1716 Algiers earthquakes, whereas three other ones depict very recent ages, i.e. younger than 1700 AD. Potential of these secondary extrados faults for determining paleoseismic events and thrust behaviour is discussed

    Do case-only designs yield consistent results across design and different databases? A case study of hip fractures and benzodiazepines.

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    BACKGROUND: The case-crossover (CXO) and self-controlled case series (SCCS) designs are increasingly used in pharmacoepidemiology. In both, relative risk estimates are obtained within persons, implicitly controlling for time-fixed confounding variables. OBJECTIVES: To examine the consistency of relative risk estimates of hip/femur fractures (HFF) associated with the use of benzodiazepines (BZD) across case-only designs in two databases (DBs), when a common protocol was applied. METHODS: CXO and SCCS studies were conducted in BIFAP (Spain) and CPRD (UK). Exposure to BZD was divided into non-use, current, recent and past use. For CXO, odds ratios (OR; 95%CI) of current use versus non-use/past were estimated using conditional logistic regression adjusted for co-medications (AOR). For the SCCS, conditional Poisson regression was used to estimate incidence rate ratios (IRR; 95%CI) of current use versus non/past-use, adjusted for age. To investigate possible event-exposure dependence the relative risk in the 30 days prior to first BZD exposure was also evaluated. RESULTS: In the CXO current use of BZD was associated with an increased risk of HFF in both DBs, AORBIFAP = 1.47 (1.29-1.67) and AORCPRD = 1.55 (1.41-1.70). In the SCCS, IRRs for current exposure was 0.79 (0.72-0.86) in BIFAP and 1.21 (1.13-1.30) in CPRD. However, when we considered separately the 30-day pre-exposure period, the IRR for current period was 1.43 (1.31-1.57) in BIFAP and 1.37 (1.27-1.47) in CPRD. CONCLUSIONS: CXO designs yielded consistent results across DBs, while initial SCCS analyses did not. Accounting for event-exposure dependence, estimates derived from SCCS were more consistent across DBs and designs

    Intelligent Health Monitoring of Machine Bearings Based on Feature Extraction

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    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

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    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

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    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

    Textile Dyes Removal From Wastewater Using Recent Promising Composites: A Review

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    Dyes are widely used in many fields such as textiles, leather, paper, plastics… These industries consume a large amount of water, and in some textile dyeing operations, as much as 15-20% of dyes used do not attach to the fibers, so they are lost to wastewater, and the resulting colored effluents can represent a serious water pollution problem due to their color content and toxic components which, over time, are directly involved in the degradation of our ecosystem. The usual effluent treatment involves biological systems like activated sludge; however, conventional treatment has not efficiently removed the effluent dye due to the recalcitrant nature of the dyes and the diverse composition of the effluent. Some conventional methods which have been largely used to eliminate dyes ions from various industrial effluents are often costly, especially in removing dye ions from dilute solutions. Adsorption is considered quite attractive in terms of its efficiency of removal from dilute solutions. Recently, various composites have received wide attention due to their outstanding properties in wastewater treatment. However, non-biodegradable synthetic polymers are largely applied as the organic components of these composites, leading to negative environmental impacts. In this paper, after a brief description of textile dyes, their toxicity and the conventional physic-chemical processes used in the degradation of dyes, we have focused on some of the work published over the past 5 years using the most promising composites for environmental purposes. Overall, the biopolymers and magnetic-based composites have demonstrated outstanding removal capabilities for a large range of dyes
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