161 research outputs found

    Non-cellulosic polysaccharides from cotton fibre are differently impacted by textile processing.

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    Cotton fibre is mainly composed of cellulose, although non-cellulosic polysaccharides play key roles during fibre development and are still present in the harvested fibre. This study aimed at determining the fate of non-cellulosic polysaccharides during cotton textile processing. We analyzed non-cellulosic cotton fibre polysaccharides during different steps of cotton textile processing using GC-MS, HPLC and comprehensive microarray polymer profiling to obtain monosaccharide and polysaccharide amounts and linkage compositions. Additionally, in situ detection was used to obtain information on polysaccharide localization and accessibility. We show that pectic and hemicellulosic polysaccharide levels decrease during cotton textile processing and that some processing steps have more impact than others. Pectins and arabinose-containing polysaccharides are strongly impacted by the chemical treatments, with most being removed during bleaching and scouring. However, some forms of pectin are more resistant than others. Xylan and xyloglucan are affected in later processing steps and to a lesser extent, whereas callose showed a strong resistance to the chemical processing steps. This study shows that non-cellulosic polysaccharides are differently impacted by the treatments used in cotton textile processing with some hemicelluloses and callose being resistant to these harsh treatments

    On the Dirac delta as initial condition for nonlinear Schr\"odinger equations

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    In this article we will study the initial value problem for some Schr\"odinger equations with Diraclike initial data and therefore with infinite L2 mass, obtaining positive results for subcritical nonlinearities. In the critical case and in one dimension we prove that after some renormalization the corresponding solution has finite energy. This allows us to conclude a stability result in the defocusing setting. These problems are related to the existence of a singular dynamics for Schr\"odinger maps through the so called Hasimoto transformation.Comment: 17 pages, to appear in in AnIHP Ann Non Li

    Local well-posedness and blow up in the energy space for a class of L2 critical dispersion generalized Benjamin-Ono equations

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    We consider a family of dispersion generalized Benjamin-Ono equations (dgBO) which are critical with respect to the L2 norm and interpolate between the critical modified (BO) equation and the critical generalized Korteweg-de Vries equation (gKdV). First, we prove local well-posedness in the energy space for these equations, extending results by Kenig, Ponce and Vega concerning the (gKdV) equations. Second, we address the blow up problem in the spirit of works of Martel and Merle on the critical (gKdV) equation, by studying rigidity properties of the (dgBO) flow in a neighborhood of solitons. We prove that when the model is close to critical (gKdV), solutions of negative energy close to solitons blow up in finite or infinite time in the energy space. The blow up proof requires in particular extensions to (dgBO) of monotonicity results for localized versions of L2 norms by pseudo-differential operator tools.Comment: Submitte

    The sources and dynamics of fine-grained sediment degrading the Freshwater Pearl Mussel (Margaritifera margaritifera) beds of the River Torridge, Devon, UK

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    The Freshwater Pearl Mussel (Margaritifera margaritifera) is an endangered organism across its entire range. It has a complex life cycle and stringent habitat requirements and is therefore an indicator species for the general ecosystem health of host rivers. Whereas historical intensive pearl fishing contributed to population declines, excess nutrient and sediment loss associated with current land use pressures in host river catchments, including modern intensive farming practices, are now highlighted as primary contributory factors. Accordingly, this study investigated the sources and dynamics of fine-grained sediment sampled in the mussel beds of the River Torridge, SW England. Sediment source fingerprinting using a combination of colorimetric and radiometric tracers to construct different composite signatures revealed the importance of roads both as a sediment source and delivery pathway for fine-grained sediment mobilised from fields predominantly supporting lowland livestock farming. Grassland fields with evidence of soil poaching were highlighted as important sediment sources, but equally, riparian woodland was also identified as important, especially during the latter stages of consecutive runoff events when its rainfall buffering capacity was exceeded. Bed sediment storage levels (median up to 393 g m−2) were found to be low (41st percentile) compared to typical values reported by a recent strategic scale survey across England and Wales, whereas elevated turbidity peaks were shown to be long duration (days) in conjunction with consecutive days of rainfall and corresponding runoff events. Hysteresis patterns varied but were generally clockwise during the largest runoff events associated with consecutive rain days; again, suggesting mobilisation of sediment from proximal woodland sources following exceedance of rainfall buffering capacity. In combination, the data assembled by this study provides a basis for planning sediment control measures for protecting the Freshwater Pearl Mussel (FPM) beds from excessive fine-grained sediment inputs associated with the intensive use of primarily grazing land

    Quantum Zakharov Model in a Bounded Domain

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    We consider an initial boundary value problem for a quantum version of the Zakharov system arising in plasma physics. We prove the global well-posedness of this problem in some Sobolev type classes and study properties of solutions. This result confirms the conclusion recently made in physical literature concerning the absence of collapse in the quantum Langmuir waves. In the dissipative case the existence of a finite dimensional global attractor is established and regularity properties of this attractor are studied. For this we use the recently developed method of quasi-stability estimates. In the case when external loads are C∞C^\infty functions we show that every trajectory from the attractor is C∞C^\infty both in time and spatial variables. This can be interpret as the absence of sharp coherent structures in the limiting dynamics.Comment: 27 page

    Travelling waves for the Gross-Pitaevskii equation II

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    The purpose of this paper is to provide a rigorous mathematical proof of the existence of travelling wave solutions to the Gross-Pitaevskii equation in dimensions two and three. Our arguments, based on minimization under constraints, yield a full branch of solutions, and extend earlier results, where only a part of the branch was built. In dimension three, we also show that there are no travelling wave solutions of small energy.Comment: Final version accepted for publication in Communications in Mathematical Physics with a few minor corrections and added remark

    Immune responses during COVID-19 infection

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    Over the past 16 years, three coronaviruses (CoVs), severe acute respiratory syndrome CoV (SARS-CoV) in 2002, Middle East respiratory syndrome CoV (MERS-CoV) in 2012 and 2015, and SARS-CoV-2 in 2020, have been causing severe and fatal human epidemics. The unpredictability of coronavirus disease-19 (COVID-19) poses a major burden on health care and economic systems across the world. This is caused by the paucity of in-depth knowledge of the risk factors for severe COVID-19, insufficient diagnostic tools for the detection of SARS-CoV-2, as well as the absence of specific and effective drug treatments. While protective humoral and cellular immune responses are usually mounted against these betacoronaviruses, immune responses to SARS-CoV2 sometimes derail towards inflammatory tissue damage, leading to rapid admissions to intensive care units. The lack of knowledge on mechanisms that tilt the balance between these two opposite outcomes poses major threats to many ongoing clinical trials dealing with immunostimulatory or immunoregulatory therapeutics. This review will discuss innate and cognate immune responses underlying protective or deleterious immune reactions against these pathogenic coronaviruses

    Construire des pratiques participatives dans les bibliothèques

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    Participer et faire participer les citoyens, les publics ? Qui participe, comment et jusqu’où ? Que devient le professionnel avec ce nouveau paradigme ? Comment emporter l’adhésion des habitants ? De plus en plus de bibliothèques s’engagent activement dans la participation, selon des modalités et des niveaux d’implication variés. Cette mutation des pratiques renouvelle les réflexions engagées autour des publics : ne plus seulement mettre les publics au centre du cercle mais créer les conditions pour les accompagner à dessiner ce cercle. Empowerment, co-construction, crowdsourcing, savoirs partagés, participation démocratique… cet ouvrage permet de clarifier les notions attachées aux dynamiques participatives et propose un cadre de réflexion qui permettra aux bibliothécaires de construire leurs modes d’action entre PirateBox, BiblioRemix, comités d’usagers, design de service et autres formes de projets participatifs. Organisé en trois parties - Repenser la bibliothèque ensemble, Partager les savoirs, Décider ensemble ? – ce volume présente également un ensemble de témoignages de praticiens du sujet, en France et aux États-Unis, de la préfiguration d’une bibliothèque à son réaménagement, en passant par la création de plateformes collaboratives et de nouveaux services. L’expérience d’un musée et l’aventure d’un centre social viennent enrichir le panorama

    Co-bedding as a Comfort measure For Twins undergoing painful procedures (CComForT Trial)

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    <p>Abstract</p> <p>Background</p> <p>Co-bedding, a developmental care strategy, is the practice of caring for diaper clad twins in one incubator (versus separating and caring for each infant in separate incubators), thus creating the opportunity for skin-to-skin contact and touch between the twins. In studies of mothers and their infants, maternal skin-to-skin contact has been shown to decrease procedural pain response according to both behavioral and physiological indicators in very preterm neonates. It is uncertain if this comfort is derived solely from maternal presence or from stabilization of regulatory processes from direct skin contact. The intent of this study is to compare the comfort effect of co-bedding (between twin infants who are co-bedding and those who are not) on infant pain response and physiologic stability during a tissue breaking procedure (heelstick).</p> <p>Methods/Design</p> <p>Medically stable preterm twin infants admitted to the Neonatal Intensive Care Unit will be randomly assigned to a co-bedding group or a standard care group. Pain response will be measured by physiological and videotaped facial reaction using the Premature Infant Pain Profile scale (PIPP). Recovery from the tissue breaking procedure will be determined by the length of time for heart rate and oxygen saturation to return to baseline. Sixty four sets of twins (n = 128) will be recruited into the study. Analysis and inference will be based on the intention-to-treat principle.</p> <p>Discussion</p> <p>If twin contact while co-bedding is determined to have a comforting effect for painful procedures, then changes in current neonatal care practices to include co-bedding may be an inexpensive, non invasive method to help maintain physiologic stability and decrease the long term psychological impact of procedural pain in this high risk population. Knowledge obtained from this study will also add to existing theoretical models with respect to the exact mechanism of comfort through touch.</p> <p>Trial registration</p> <p>NCT00917631</p
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