72 research outputs found

    Numerical experiments with two smoothing type-algorithms for nonlinear complementarity problems

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    In this paper we deal with the numerical experiments of two smoothing descent-type algorithms for solving nonlinear complementarity problems (NCP). The first algorithm is due to Kanzow and the second one is due to Peng. These algorithms are both based on the reformulation of (NCP) as unconstrained minimization problems by using some smoothing merit functions including the so-called (NCP)-functions. Under suitable conditions they both showed that any stationary point of these problems are solutions of (NCP). For their numerical performances many strategies are used. Finally, these algorithms are applied to some problems of (NCP) found in the literature

    Particles with anomalous magnetic moment in external e.m. fields: the proper time formulation

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    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

    Searching for the seafloor signature of the 21 May 2003 Boumerdès earthquake offshore central Algeria

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    Shaking by moderate to large earthquakes in the Mediterranean Sea has proved in the past to potentially trigger catastrophic sediment collapse and flow. On 21 May 2003, a magnitude 6.8 earthquake located near Boumerdès (central Algerian coast) triggered large turbidity currents responsible for 29 submarine cable breaks at the foot of the continental slope over ~150 km from west to east. Seafloor bathymetry and backscatter imagery show the potential imprints of the 2003 event and of previous events. Large slope scarps resulting from active deformation may locally enhance sediment instabilities, although faults are not directly visible at the seafloor. Erosion is evident at the foot of the margin and along the paths of the numerous canyons and valleys. Cable breaks are located at the outlets of submarine valleys and in areas of turbiditic levee overspilling and demonstrate the multi-source and multi-path character of the 2003 turbiditic event. Rough estimates of turbidity flow velocity are not straightforward because of the multiple breaks along the same cable, but seem compatible with those measured in other submarine cable break studies elsewhere. <br><br> While the signature of the turbidity currents is mostly erosional on the continental slope, turbidite beds alternating with hemipelagites accumulate in the distal reaches of sediment dispersal systems. In perspective, more chronological work on distal turbidite successions offshore Algeria offers promising perspectives for paleoseismology reconstructions based on turbidite dating, if synchronous turbidites along independent sedimentary dispersal systems are found to support triggering by major earthquakes. Preliminary results on sediment core PSM-KS23 off Boumerdès typically show a 800-yr interval between turbidites during the Holocene, in accordance with the estimated mean seismic cycle on land, even if at this stage it is not yet possible to prove the earthquake origin of all the turbidites

    Incidence, risk factors and re-exacerbation rate of severe asthma exacerbations in a multinational, multidatabase pediatric cohort study

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    Background: There are sparse real-world data on severe asthma exacerbations (SAE) in children. This multinational cohort study assessed the incidence of and risk factors for SAE and the incidence of asthma-related rehospitalization in children with asthma. Methods: Asthma patients 5-17 years old with ≥1 year of follow-up were identified in six European electronic databases from the Netherlands, Italy, the UK, Denmark and Spain in 2008-2013. Asthma was defined as ≥1 asthma-specific disease code within 3 months of prescriptions/dispensing of asthma medication. Severe asthma was defined as high-dosed inhaled corticosteroids plus a second controller. SAE was defined by systemic corticosteroids, emergency department visit and/or hospitalization all for reason of asthma. Risk factors for SAE were estimated by Poisson regression analyses. Results: The cohort consisted of 212 060 paediatric asthma patients contributing to 678 625 patient-years (PY). SAE rates ranged between 17 and 198/1000 PY and were higher in severe asthma and highest in severe asthma patients with a history of exacerbations. Prior SAE (incidence rate ratio 3-45) and younger age increased the SAE risk in all countries, whereas obesity, atopy and GERD were a risk factor in some but not all countries. Rehospitalization rates were up to 79% within 1 year. Conclusions: In a real-world setting, SAE rates were highest in children with severe asthma with a history of exacerbations. Many severe asthma patients were rehospitalized within 1 year. Asthma management focusing on prevention of SAE is important to reduce the burden of asthma

    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

    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

    A Maude-Based Tool for Simulating DIMA Model

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