1,127 research outputs found

    Quantum hypercomputation based on the dynamical algebra su(1,1)

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    An adaptation of Kieu's hypercomputational quantum algorithm (KHQA) is presented. The method that was used was to replace the Weyl-Heisenberg algebra by other dynamical algebra of low dimension that admits infinite-dimensional irreducible representations with naturally defined generalized coherent states. We have selected the Lie algebra su(1,1)\mathfrak{su}(1,1), due to that this algebra posses the necessary characteristics for to realize the hypercomputation and also due to that such algebra has been identified as the dynamical algebra associated to many relatively simple quantum systems. In addition to an algebraic adaptation of KHQA over the algebra su(1,1)\mathfrak{su}(1,1), we presented an adaptations of KHQA over some concrete physical referents: the infinite square well, the infinite cylindrical well, the perturbed infinite cylindrical well, the P{\"o}sch-Teller potentials, the Holstein-Primakoff system, and the Laguerre oscillator. We conclude that it is possible to have many physical systems within condensed matter and quantum optics on which it is possible to consider an implementation of KHQA.Comment: 25 pages, 1 figure, conclusions rewritten, typing and language errors corrected and latex format changed minor changes elsewhere and

    Lysyl oxidases regulate fibrillar collagen remodelling in idiopathic pulmonary fibrosis.

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    Idiopathic pulmonary fibrosis (IPF) is a progressive scarring disease of the lung with few effective therapeutic options. Structural remodelling of the extracellular matrix [i.e. collagen cross-linking mediated by the lysyl oxidase (LO) family of enzymes (LOX, LOXL1-4)] might contribute to disease pathogenesis and represent a therapeutic target. This study aimed to further our understanding of the mechanisms by which LO inhibitors might improve lung fibrosis. Lung tissues from IPF and non-IPF subjects were examined for collagen structure (second harmonic generation imaging) and LO gene (microarray analysis) and protein (immunohistochemistry and western blotting) levels. Functional effects (collagen structure and tissue stiffness using atomic force microscopy) of LO inhibitors on collagen remodelling were examined in two models, collagen hydrogels and decellularized human lung matrices. LOXL1/LOXL2 gene expression and protein levels were increased in IPF versus non-IPF. Increased collagen fibril thickness in IPF versus non-IPF lung tissues correlated with increased LOXL1/LOXL2, and decreased LOX, protein expression. β-Aminoproprionitrile (β-APN; pan-LO inhibitor) but not Compound A (LOXL2-specific inhibitor) interfered with transforming growth factor-β-induced collagen remodelling in both models. The β-APN treatment group was tested further, and β-APN was found to interfere with stiffening in the decellularized matrix model. LOXL1 activity might drive collagen remodelling in IPF lungs. The interrelationship between collagen structural remodelling and LOs is disrupted in IPF lungs. Inhibition of LO activity alleviates fibrosis by limiting fibrillar collagen cross-linking, thereby potentially impeding the formation of a pathological microenvironment in IPF

    Producing cereal seeds for organic agriculture

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    This tool is a data sheet that can be used by French farmers who produce or want to produce cereal seeds in organic conditions. It provides advice starting from the contract signing to the seed drying, going through the specificities of the crop, the sowing, specific pests and their management, and the harvest

    Treatment of asymptomatic carotid artery disease: Similar early outcomes after carotid stenting for high-risk patients and endarterectomy for standard-risk patients

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    BackgroundThe role of carotid angioplasty and stenting (CAS) in the treatment of asymptomatic patients with carotid disease remains controversial. The purpose of this report is to compare outcomes in asymptomatic patients treated with CAS and carotid endarterectomy (CEA). This was the initial experience performing CAS for most of the surgeons. For comparison, we also report our outcomes in standard-risk patients treated concurrently with CEA during the same period of time.MethodsA retrospective, nonrandomized review of asymptomatic patients undergoing CEA or CAS at Washington University Medical Center in St. Louis was done. Patients with >70% asymptomatic carotid stenosis treated between September 2003 and April 2005 were identified. CEA was the first therapeutic consideration in all patients. CAS was reserved for high-risk patients. Thirty-day outcomes of stroke or death were recorded. During this time interval, 248 patients were treated including with 93 CAS and with 145 CEA. Symptomatic or clinically detected adverse outcomes such as myocardial infarction (MI), arrhythmia, renal failure, or pulmonary complications were noted but were not the primary end points of this review. This study addresses only the periprocedural outcomes of CEA and CAS in asymptomatic patients. No data >30-day follow-up are included.ResultsDuring this period, 93 CAS and 145 CEA procedures were done in asymptomatic patients. Patient characteristics in both groups were similar. Carotid protection devices were used in 91.4% of CAS patients. The results in the CAS group showed one death (1.1%) and one stroke (1.1%). In the CEA group, three strokes occurred (2.1%, P = 0.9999), one associated with death (0.7%, P = 0.9999). The CAS group had 1.34 ± 0.83 risk factors vs 0.39 ± 0.58 in the CEA group (P < .0001). Median CAS and CEA length of stay was 1 day.ConclusionsCAS for asymptomatic carotid stenosis demonstrated equivalent outcomes compared with CEA, despite CAS being reserved for use in a disadvantaged subset of high-risk patients owing to anatomic risk factors or medical comorbidities. These results suggest CAS should be considered a reasonable treatment option in the high-risk but asymptomatic patient. Enthusiasm for CAS should be tempered by the recognition that long-term outcomes in CAS-treated asymptomatic patients remain unknown

    Droit de la construction : de la jurisprudence à la pratique notariale

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    "Parce que le contentieux de la construction concerne les notaires à bien des égards, cette nouvelle chronique, rédigée par des universitaires et des praticiens, a pour objectif premier de brosser un panorama des décisions importantes rendues au cours de l\u27année 2012 en la matière. Les signataires de ces lignes ont ensuite cherché, dans le cadre de cette collaboration entre chercheurs et notaires, à enrichir leurs commentaires de conseils pratiques. Ainsi, au cours de l\u27année écoulée, la Cour de cassation s\u27est prononcée sur des questions générales d\u27organisation de l\u27immeuble, précisant la liberté de choix entre le statut de la copropriété et la division en volumes ou revenant sur les règles applicables aux travaux réalisés sur un mur mitoyen. Des précisions ont également été apportées sur le champ d\u27application de la responsabilité décennale des constructeurs, puisqu\u27il a été rappelé que le vendeur même non professionnel d\u27un immeuble rénové peut, à certaines conditions, engager sa responsabilité décennale, de même que cette cause de responsabilité est également susceptible de s\u27appliquer lorsque les dommages affectant un immeuble neuf causent des préjudices à des tiers ou se matérialisent par un simple risque d\u27écroulement, sans que la catastrophe ne soit encore survenue. Un arrêt important précise en outre, dans le domaine des assurances, la distinction entre la faute lourde, couverte, et celle intentionnelle, dont l\u27assureur ne répondra pas. On relèvera finalement trois décisions importantes en matière de vente d\u27immeubles à construire. Deux concernent la rédaction des actes, quant à la distinction entre les notions d\u27achèvement et de livraison d\u27une part, puis relativement aux clauses d\u27allongement de délai de livraison pour intempéries, d\u27autre part. Le dernier revient sur la question importante la rénovation en précisant l\u27étendue de la responsabilité du notaire dans le choix entre le modèle de la vente en l\u27état futur d\u27achèvement et celui de la vente d\u27immeuble à rénover." Gwenaëlle Durand-Pasquie

    Molecular simulations unravel the molecular principles that mediate selective permeability of carboxysome shell protein

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    Bacterial microcompartments (BMCs) are nanoscale proteinaceous organelles that encapsulate enzymes from the cytoplasm using an icosahedral protein shell that resembles viral capsids. Of particular interest are the carboxysomes (CBs), which sequester the CO 2 -fixing enzymes ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) to enhance carbon assimilation. The carboxysome shell serves as a semi-permeable barrier for passage of metabolites in and out of the carboxysome to enhance CO 2 fixation. How the protein shell directs influx and efflux of molecules in an effective manner has remained elusive. Here we use molecular dynamics and umbrella sampling calculations to determine the free-energy profiles of the metabolic substrates, bicarbonate, CO 2 and ribulose bisphosphate and the product 3-phosphoglycerate associated with their transition through the major carboxysome shell protein CcmK2. We elucidate the electrostatic charge-based permeability and key amino acid residues of CcmK2 functioning in mediating molecular transit through the central pore. Conformational changes of the loops forming the central pore may also be required for transit of specific metabolites. The importance of these in-silico findings is validated experimentally by site-directed mutagenesis of the key CcmK2 residue Serine 39. This study provides insight into the mechanism that mediates molecular transport through the shells of carboxysomes, applicable to other BMCs. It also offers a predictive approach to investigate and manipulate the shell permeability, with the intend of engineering BMC-based metabolic modules for new functions in synthetic biology

    Impact of mineral dust on short wave and long wave radiation: evaluation of different vertically resolved parameterization sin 1-D radiative transfer computations

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    Aerosol radiative properties are investigated in southeastern Spain during a dust event on 16–17 June 2013 in the framework of the ChArMEx/ADRIMED (Chemistry-Aerosol Mediterranean Experiment/Aerosol Direct Radiative Impact on the regional climate in the MEDiterranean region) campaign. Particle optical and microphysical properties from ground-based sun/sky photometer and lidar measurements, as well as in situ measurements on board the SAFIRE ATR 42 French research aircraft, are used to create a set of different levels of input parameterizations, which feed the 1-D radiative transfer model (RTM) GAME (Global Atmospheric ModEl). We consider three datasets: (1) a first parameterization based on the retrievals by an advanced aerosol inversion code (GRASP; Generalized Retrieval of Aerosol and Surface Properties) applied to combined photometer and lidar data, (2) a parameterization based on the photometer columnar optical properties and vertically resolved lidar retrievals with the two-component Klett–Fernald algorithm, and (3) a parameterization based on vertically resolved optical and microphysical aerosol properties measured in situ by the aircraft instrumentation. Once retrieved, the outputs of the RTM in terms of both shortwave and longwave radiative fluxes are compared against ground and in situ airborne measurements. In addition, the outputs of the model in terms of the aerosol direct radiative effect are discussed with respect to the different input parameterizations. Results show that calculated atmospheric radiative fluxes differ no more than 7 % from the measured ones. The three parameterization datasets produce a cooling effect due to mineral dust both at the surface and the top of the atmosphere. Aerosol radiative effects with differences of up to 10 W m−2 in the shortwave spectral range (mostly due to differences in the aerosol optical depth) and 2 W m−2 for the longwave spectral range (mainly due to differences in the aerosol optical depth but also to the coarse mode radius used to calculate the radiative properties) are obtained when comparing the three parameterizations. The study reveals the complexity of parameterizing 1-D RTMs as sizing and characterizing the optical properties of mineral dust is challenging. The use of advanced remote sensing data and processing, in combination with closure studies on the optical and microphysical properties from in situ aircraft measurements when available, is recommended.This work is part of the ChArMEx project supported by CNRS-INSU, ADEME, Météo-France, and CEA in the framework of the multidisciplinary program MISTRALS (Mediterranean Integrated STudies at Regional And Local Scales; http://mistrals-home.org/, last access: 15 January 2018). Lidar measurements were supported by the ACTRIS (Aerosols, Clouds, and Trace Gases Research Infrastructure Network) Research Infrastructure Project funded by the European Union's Horizon 2020 research and innovation program under grant agreement no. 654109. The Barcelona team acknowledges the Spanish Ministry of Economy and Competitiveness (project TEC2015-63832-P) and EFRD (European Fund for Regional Development); the Department of Economy and Knowledge of the Catalan autonomous government (grant 2014 SGR 583) and the Unidad de Excelencia Maria de Maeztu (project MDM-2016-0600) financed by the Spanish Agencia Estatal de Investigación. The authors also thank the Spanish Ministry of Science, Innovation and Universities (ref. CGL2017-90884-REDT). This work was also supported by the Juan de la Cierva-Formación program (grant FJCI-2015-23904). Paola Formenti and Cyrielle Denjean acknowledge the support of the French National Research Agency (ANR) through the ADRIMED program (contract ANR-11-BS56-0006)

    Overt ischemic colitis after endovascular repair of aortoiliac aneurysms

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    AbstractObjectiveControversy exists as to the cause of ischemic colitis complicating endovascular aneurysm repair. Occlusion of the hypogastric arteries (HAs) during endovascular repair of aortoiliac aneurysms (AIAs) results in a significant incidence of buttock claudication, and has been suggested as a causative factor in the development of postprocedural colonic ischemia, in addition to factors such as systemic hypotension, embolization of atheromatous debris, and interruption of inferior mesenteric artery inflow. To analyze the relationship between perioperative HA occlusion and postoperative ischemic colitis, we reviewed our experience over 2 years with Food and Drug Administration–approved endovascular graft devices for treatment of AIAs.MethodsElective repair of AIAs with bifurcated endovascular grafts was performed in 233 patients over a 2-year period. These included 184 AneuRx grafts, 17 Ancure grafts, and 32 Excluder grafts. During the experience, 44 patients (18.9%) underwent unilateral perioperative HA occlusion (28 right, 16 left) during the course of endovascular AIA repair, and 1 patient (0.4%) underwent bilateral HA occlusion.ResultsIn 4 patients (1.7%) signs and symptoms of ischemic colitis developed 2.0 ± 1.4 days postoperatively. In all patients the diagnosis was confirmed at sigmoidoscopy, and initial treatment included bowel rest, hydration, and intravenous antibiotic agents. Three patients with bilateral patent HAs required colonic resection 14.7 ± 9.7 days after the initial diagnosis, and 2 of these 3 patients died in the postoperative period. Pathologic findings confirmed the presence of atheroemboli in the colonic vasculature in all 3 patients who underwent colonic resection. The fourth patient had undergone multiple manipulations of the left HA in an unsuccessful attempt to preserve patency of this vessel during AIA repair. This patient recovered completely with nonoperative management. Perioperative unilateral HA occlusion was not associated with a significantly higher incidence of postoperative ischemic colitis.ConclusionPerioperative HA occlusion during aortoiliac open or endovascular surgery may contribute to development of the rare but potentially lethal complication of ischemic colitis. However, our extensive experience suggests that embolization of atheromatous debris to the HA tissue beds during endovascular manipulations, rather than proximal HA occlusion, is the primary cause of clinically significant ischemic colitis after endovascular aneurysm repair

    Study of the correlation between columnar aerosol burden, suspended matter at ground and chemical components in a background European environment

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    Although routinely monitored by ground based air quality networks, the particulate matter distribution could be eventually better described with remote sensing techniques. However, valid relationships between ground level and columnar ground based quantities should be known beforehand. In this study we have performed a comparison between particulate matter measurements at ground level at different cut sizes (10, 2.5 and 1.0 mm), and the aerosol optical depth obtained by means of a ground based sunphotometer during a multiinstrumental field campaign held in El Arenosillo (Huelva, Spain) from 28 June to 4 July 2006. All the PM fractions were very well correlated with AOD with correlation coefficients that ranged from 0.71 to 0.81 for PM10, PM2.5 and PM1. Furthermore, the influence of the mixing layer height in the correlations was explored. The improvement in the correlation when the vertical distribution is taken into account was significant for days with a homogeneous mixing layer. Moreover, the chemical analysis of the individual size fractions allowed us to study the origin of the particulate matter. Secondary components were the most abundant and also well correlated in the three size fractions; but for PM10 fraction, chemical species related to marine origin were best correlated. Finally, we obtained a relationship between MODIS L3 AOD from collection 5.1 and the three PM cut sizes. In spite of being a relatively clean environment, all the techniques were able to capture similar day to day variations during this field campaign.Peer ReviewedPostprint (published version

    Genetic Studies of Sulfadiazine-resistant and Methionine-requiring \u3cem\u3eNeisseria\u3c/em\u3e Isolated From Clinical Material

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    Deoxyribonucleate (DNA) preparations were extracted from Neisseria meningitidis (four isolates from spinal fluid and blood) and N. gonorrhoeae strains, all of which were resistant to sulfadiazine upon primary isolation. These DNA preparations, together with others from in vitro mutants of N. meningitidis and N. perflava, were examined in transformation tests by using as recipient a drug-susceptible strain of N. meningitidis (Ne 15 Sul-s Met+) which was able to grow in a methionine-free defined medium. The sulfadiazine resistance typical of each donor was introduced into the uniform constitution of this recipient. Production of p-aminobenzoic acid was not significantly altered thereby. Transformants elicited by DNA from the N. meningitidis clinical isolates were resistant to at least 200 μg of sulfadiazine/ml, and did not show a requirement for methionine (Sul-r Met+). DNA from six strains of N. gonorrhoeae, which were isolated during the period of therapeutic use of sulfonamides, conveyed lower degrees of resistance and, invariably, a concurrent methionine requirement (Sul-r/Met−). The requirement of these transformants, and that of in vitro mutants selected on sulfadiazine-agar, was satisfied by methionine, but not by vitamin B12, homocysteine, cystathionine, homoserine, or cysteine. Sul-r Met+ and Sul-r/Met− loci could coexist in the same genome, but were segregated during transformation. On the other hand, the dual Sul-r/Met− properties were not separated by recombination, but were eliminated together. DNA from various Sul-r/Met− clones tested against recipients having nonidentical Sul-r/Met− mutant sites yielded Sul-s Met+ transformants. The met locus involved is genetically complex, and will be a valuable tool for studies of genetic fine structure of members of Neisseria, and of genetic homology between species
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