594 research outputs found

    Experiments on wind-perturbed rogue wave hydrodynamics using the Peregrine breather model

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    Being considered as a prototype for description of oceanic rogue waves, the Peregrine breather solution of the nonlinear Schrödinger equation has been recently observed and intensely investigated experimentally in particular within the context of water

    Spectral up- and downshifting of Akhmediev breathers under wind forcing

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    We experimentally and numerically investigate the effect of wind forcing on the spectral dynamics of Akhmediev breathers, a wave-type known to model the modulation instability. We develop the wind model to the same order in steepness as the higher order modifcation of the nonlinear Schroedinger equation, also referred to as the Dysthe equation. This results in an asymmetric wind term in the higher order, in addition to the leading order wind forcing term. The derived model is in good agreement with laboratory experiments within the range of the facility's length. We show that the leading order forcing term amplifies all frequencies equally and therefore induces only a broadening of the spectrum while the asymmetric higher order term in the model enhances higher frequencies more than lower ones. Thus, the latter term induces a permanent upshift of the spectral mean. On the other hand, in contrast to the direct effect of wind forcing, wind can indirectly lead to frequency downshifts, due to dissipative effects such as wave breaking, or through amplification of the intrinsic spectral asymmetry of the Dysthe equation. Furthermore, the definitions of the up- and downshift in terms of peak- and mean frequencies, that are critical to relate our work to previous results, are highlighted and discussed.Comment: 30 pages, 11 figure

    Experiments on wind-perturbed rogue wave hydrodynamics using the Peregrine breather model

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    International audienceBeing considered as a prototype for description of oceanic rogue waves (RWs), the Peregrine breather solution of the nonlinear Schrodinger equation (NLS) has been recently observed and intensely investigated experimentally in particular within the context of water waves. Here, we report the experimental results showing the evolution of the Peregrine solution in the presence of wind forcing in the direction of wave propagation. The results show the persistence of the breather evolution dynamics even in the presence of strong wind and chaotic wave eld generated by it. Furthermore, we have shown that characteristic spectrum of the Peregrine breather persists even at the highest values of the generated wind velocities thus making it a viable characteristic for prediction of rogue waves

    What they fill in today, may not be useful tomorrow: Lessons learned from studying Medical Records at the Women hospital in Tabriz, Iran

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    <p>Abstract</p> <p>Background</p> <p>The medical record is used to document patient's medical history, illnesses and treatment procedures. The information inside is useful when all needed information is documented properly. Medical care providers in Iran have complained of low quality of Medical Records. This study was designed to evaluate the quality of the Medical Records at the university hospital in Tabriz, Iran.</p> <p>Methods</p> <p>In order to get a background of the quality of documentation, 300 Medical Records were randomly selected among all hospitalized patient during September 23, 2003 and September 22, 2004. Documentation of all records was evaluated using checklists. Then, in order to combine objective data with subjective, 10 physicians and 10 nurses who were involved in documentation of Medical Records were randomly selected and interviewed using two semi structured guidelines.</p> <p>Results</p> <p>Almost all 300 Medical Records had problems in terms of quality of documentation. There was no record in which all information was documented correctly and compatible with the official format in Medical Records provided by Ministry of Health and Medical Education. Interviewees believed that poor handwriting, missing of sheets and imperfect documentation are major problems of the Paper-based Medical Records, and the main reason was believed to be high workload of both physicians and nurses.</p> <p>Conclusion</p> <p>The Medical Records are expected to be complete and accurate. Our study has unveiled that the Medical Records are not documented properly in the university hospital where the Medical Records are also used for educational purposes. Such incomplete Medical Records are not reliable resources for medical care too. Some influencing factors external to the structure of the Medical Records (i.e. human factors and work conditions) are involved.</p

    Immunogenicity of an additional mRNA-1273 SARS-CoV-2 vaccination in people with HIV with hyporesponse after primary vaccination

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    Background:The COVIH study is a prospective coronavirus disease 2019 (COVID-19) vaccination study in 1154 people with HIV (PWH), of whom 14% showed reduced antibody levels after primary vaccination. We evaluated whether an additional vaccination boosts immune responses in these hyporesponders. Methods: The primary end point was the increase in antibodies 28 days after additional mRNA-1273 vaccination. Secondary end points included neutralizing antibodies, S-specific T-cell and B-cell responses, and reactogenicity. Results:Of the 66 participants, 40 previously received 2 doses ChAdOx1-S, 22 received 2 doses BNT162b2, and 4 received a single dose Ad26.COV2.S. The median age was 63 years (interquartile range [IQR], 60–66), 86% were male, and median CD4 + T-cell count was 650/μL (IQR, 423–941). The mean S1-specific antibody level increased from 35 binding antibody units (BAU)/ mL (95% confidence interval [CI], 24–46) to 4317 BAU/mL (95% CI, 3275–5360) (P &lt; .0001). Of all participants, 97% showed an adequate response and the 45 antibody-negative participants all seroconverted. A significant increase in the proportion of PWH with ancestral S-specific CD4 + T cells (P = .04) and S-specific B cells (P = .02) was observed. Conclusions:An additional mRNA-1273 vaccination induced a robust serological response in 97% of PWH with a hyporesponse after primary vaccination.</p

    An optimised assay for quantitative, high-throughput analysis of polysialyltransferase activity

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    YesThe polysialyltransferases are biologically important glycosyltransferase enzymes responsible for the biosynthesis of polysialic acid, a carbohydrate polymer that plays a critical role in the progression of several diseases, notably cancer. Having improved the chemical synthesis and purification of the fluorescently-labelled DMB-DP3 acceptor, we report optimisation and validation of a highly sensitive cell-free high-throughput HPLC-based assay for assessment of human polysialyltransferase activity

    Le partage de la ressource en eau sur la Durance en 2050 : vers une Ă©volution du mode de gestion des grands ouvrages duranciens ?

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    Congrès SHF: Water Tensions in Europe and in the Mediterranean: water crisis by 2050?, Paris, FRA, 08-/10/2015 - 09/10/2015International audienceUne vision prospective de la gestion de l'eau du bassin de la Durance et des territoires alimentés par ses eaux à l'horizon 2050 a été élaborée, appuyée par une chaine de modèles incluant des représentations du climat, de la ressource naturelle, des demandes en eau et du fonctionnement des grands ouvrages hydrauliques (Serre-Ponçon, Castillon et Sainte-Croix), sous contraintes de respect des débits réservés, de cotes touristiques dans les retenues et de restitution d'eau stockée pour des usages en aval. Cet ensemble, validé en temps présent, a été alimenté par des projections climatiques et paramétré pour intégrer les évolutions du territoire décrites par des scénarios de développement socio-économique avec une hypothèse de conservation des règles de gestion actuelles. Les résultats suggèrent à l'horizon 2050 : une hausse de la température moyenne de l'air impactant l'hydrologie de montagne ; une évolution incertaine des précipitations ; une réduction des stocks de neige et une fonte avancée dans l'année qui induisent une réduction des débits au printemps ; une diminution de la ressource en eau en période estivale ; une diminution de la demande globale en eau à l'échelle du territoire, cette demande étant fortement conditionnée par les scénarios territoriaux élaborés ici ; la satisfaction des demandes en eau en aval des ouvrages considérées comme prioritaires, au détriment de la production d'énergie en hiver (flexibilité moindre en période de pointe) et du maintien de cotes touristiques en été ;une diminution de la production d'énergie due notamment à la réduction des apports en amont des ouvrages hydroélectriques
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