Automotive leathers – evaluating the performance limits (part II)

Content: Consumers perceive leather as a durable and natural product. To support this positive image, car manufacturers have set demanding performance profiles addressing wear, emissions and sustainable manufacture. Poor performance of auto leather becomes visible as the polymeric finishing coat wears off or cracks over time. Therefore ageing property is seen as a representative key performance parameter and is determined by checking how flexible and strong a polymer coating remains after leather has been exposed to light, heat and humidity for a given time. Ageing of leather is complex to determine and depends on various parameters and requires a full system approach . In a first step different type of crusts (wet-blue, wet-white) were prepared and finished with a standard polyurethane coating. It turned out that the selection of the right fat liquors and tanning agents as well as the presence of vegetable tannins play an important role. On top of this the effective use of proper protective chemicals like anti-oxidants is needed. In a second approach the polymer coating itself was studied and optimized with regard to aged flexing and abrasion. Parameters like polymer type, crosslinking, application technology, coating thickness and impact of additives were investigated and tested when applied on the best crust leathers selected from part 1 of this work. Results show that not only is the right selection of polymers critical but also so is the way the coat is being applied . Furthermore coating thickness greatly defines wear (abrasion), lightfastness and ageing properties. Additives like dulling agents, levelers, feel agents, waxes ,fillers although needed can weaken the integrity of the polymer matrix and consequently reduce physical and chemical fastness properties. This may also apply to a certain extent to protective additives such as anti-oxidants and UV stabilizers, but when used properly their advantages outweigh the potential disadvantages. As to application, special emphasis is given to transfer coating technology which can provide advantages in application and quality consistency but also with regards to fastness properties such as wear and ageing. Take-Away: - crust leather has a critical impact on performance of finishing coat of automotive leathers and requires careful selction of products and use of protective chemical - polymer selection and use of protective chemical play an important role for achieving good aged flexing performance - type of application of finishing coat on auto leather further determines the performance of coatin

Dynamical charge density fluctuations pervading the phase diagram of a Cu-based high-Tc superconductor

Charge density waves are a common occurrence in all families of high critical temperature superconducting cuprates. Although consistently observed in the underdoped region of the phase diagram and at relatively low temperatures, it is still unclear to what extent they influence the unusual properties of these systems. Using resonant x-ray scattering we carefully determined the temperature dependence of charge density modulations in (Y,Nd)Ba$_2$Cu$_3$O$_{7-{\delta}}$ for three doping levels. We discovered short-range dynamical charge density fluctuations besides the previously known quasi-critical charge density waves. They persist up to well above the pseudogap temperature T*, are characterized by energies of few meV and pervade a large area of the phase diagram, so that they can play a key role in shaping the peculiar normal-state properties of cuprates.Comment: 34 pages, 4 figures, 11 supplementary figure

Developing a questionnaire evaluating knowledge, attitudes and behaviors on audit & feedback among general practitioners. A mixed methods study

Background: Audit and Feedback (A&F) is one of the most common strategies used to improve quality in healthcare. However, there is still lack of awareness regarding the enabling factors and barriers that could influence its effectiveness. The aim of this study was to develop a questionnaire to measure the knowledge, attitudes and behaviors of general practitioners (GPs) regarding A&F. The study was performed in the context of the EASY-NET program (project code NET-2016-02364191). Methods: The survey was developed according to two steps. Firstly, a scoping review was performed in order to map the literature on the existing similar instruments with the aim of identifying the sub-domains and possible items to include in a preliminary version of the questionnaire. In the second phase, the questionnaire was reviewed by a multidisciplinary group of experts and administrated to a convenience sample in a pilot survey. Results: Ten papers were included in the scoping review. The survey target and development methodology were heterogenous among the studies. The knowledge, attitudes and behaviors domains were assessed in six, nine and seven studies, respectively. In the first step, 126 pertinent items were extracted and categorized as follows: 8 investigated knowledge, 93 investigated attitudes, and 25 investigated behaviors. Then, 2 sub-domains were identified for knowledge, 14 for attitudes and 7 for behavior. Based on these results, a first version of the survey was developed via consensus among two authors and then revised by the multidisciplinary group of experts in the field of A&F. The final version of the survey included 36 items: 8 in the knowledge domain, 19 in the attitudes domain and 9 in the behaviors domain. The results of the pilot study among 15 GPs suggested a good acceptability and item relevance and accuracy, with positive answers totaling 100% and 93.3% in the proposed questions. Conclusions: The methodology used has shown to be a good strategy for the development of the survey. The survey will be administrated before and after the implementation of an A&F intervention to assess both baseline characteristics and changes after the intervention

Flowing Between Fermionic Fixed Points

We study holographic Wilsonian renormalization group flows for bulk spinor fields in AdS. We use this to compute the all-loop beta function for fermionic double trace operators in the dual conformal field theory.Comment: 21 pages. V2: Acknowledgement added; v3: Typo correcte

Predictors of Mortality and Cardiovascular Outcome at 6 Months after Hospitalization for COVID-19

Clinical outcome data of patients discharged after Coronavirus disease 2019 (COVID-19) are limited and no study has evaluated predictors of cardiovascular prognosis in this setting. Our aim was to assess short-term mortality and cardiovascular outcome after hospitalization for COVID-19. A prospective cohort of 296 consecutive patients discharged after COVID-19 from two Italian institutions during the first wave of the pandemic and followed up to 6 months was included. The primary endpoint was all-cause mortality. The co-primary endpoint was the incidence of the composite outcome of major adverse cardiac and cerebrovascular events (MACCE: cardiovascular death, myocardial infarction, stroke, pulmonary embolism, acute heart failure, or hospitalization for cardiovascular causes). The mean follow-up duration was 6 ± 2 months. The incidence of all-cause death was 4.7%. At multivariate analysis, age was the only independent predictor of mortality (aHR 1.08, 95% CI 1.01–1.16). MACCE occurred in 7.2% of patients. After adjustment, female sex (aHR 2.6, 95% CI 1.05–6.52), in-hospital acute heart failure during index hospitalization (aHR 3.45, 95% CI 1.19–10), and prevalent atrial fibrillation (aHR 3.05, 95% CI 1.13–8.24) significantly predicted the incident risk of MACCE. These findings may help to identify patients for whom a closer and more accurate surveillance after discharge for COVID-19 should be considered

Holographic Wilsonian flows and emergent fermions in extremal charged black holes

We study holographic Wilsonian RG in a general class of asymptotically AdS backgrounds with a U(1) gauge field. We consider free charged Dirac fermions in such a background, and integrate them up to an intermediate radial distance, yielding an equivalent low energy dual field theory. The new ingredient, compared to scalars, involves a `generalized' basis of coherent states which labels a particular half of the fermion components as coordinates or momenta, depending on the choice of quantization (standard or alternative). We apply this technology to explicitly compute RG flows of charged fermionic operators and their composites (double trace operators) in field theories dual to (a) pure AdS and (b) extremal charged black hole geometries. The flow diagrams and fixed points are determined explicitly. In the case of the extremal black hole, the RG flows connect two fixed points at the UV AdS boundary to two fixed points at the IR AdS_2 region. The double trace flow is shown, both numerically and analytically, to develop a pole singularity in the AdS_2 region at low frequency and near the Fermi momentum, which can be traced to the appearance of massless fermion modes on the low energy cut-off surface. The low energy field theory action we derive exactly agrees with the semi-holographic action proposed by Faulkner and Polchinski in arXiv:1001.5049 [hep-th]. In terms of field theory, the holographic version of Wilsonian RG leads to a quantum theory with random sources. In the extremal black hole background the random sources become `light' in the AdS_2 region near the Fermi surface and emerge as new dynamical degrees of freedom.Comment: 37 pages (including 8 pages of appendix), 10 figures and 2 table

Efficacy of the treatment of developmental language disorder: A systematic review

Background. Language disorder is the most frequent developmental disorder in childhood and it has a significant negative impact on children’s development. The goal of the present review was to systematically analyze the effectiveness of interventions in children with developmental language disorder (DLD) from an evidence-based perspective. Methods. We considered systematic reviews, meta-analyses of randomized controlled trials (RCTs), control group cohort studies on any type of intervention aimed at improving children’s skills in the phono-articulatory, phonological, semantic-lexical, and morpho-syntactic fields in preschool and primary school children (up to eight years of age) that were diagnosed with DLD.We identified 27 full-length studies, 26 RCT and one review. Results. Early intensive intervention in three- and four-year-old children has a positive effect on phonological expressive and receptive skills and acquisitions are maintained in the medium term. Less evidence is available on the treatment of expressive vocabulary (and no evidence on receptive vocabulary). Intervention on morphological and syntactic skills has effective results on expressive (but not receptive) skills; however, a number of inconsistent results have also been reported. Only one study reports a positive effect of treatment on inferential narrative skills. Limited evidence is also available on the treatment of meta-phonological skills. More studies investigated the effectiveness of interventions on general language skills, which now appears as a promising area of investigation, even though results are not all consistent. Conclusions. The effectiveness of interventions over expressive and receptive phonological skills, morpho-syntactic skills, as well as inferential skills in narrative context underscores the importance that these trainings be implemented in children with DLD

Performance Of A Liquid Argon Time Projection Chamber Exposed To The WANF Neutrino Beam

We present the results of the first exposure of a Liquid Argon TPC to a multi-GeV neutrino beam. The data have been collected with a 50 liters ICARUS-like chamber located between the CHORUS and NOMAD experiments at the CERN West Area Neutrino Facility (WANF). We discuss both the instrumental performance of the detector and its capability to identify and reconstruct low multiplicity neutrino interactions.Comment: 14 pages, 12 figures. Submitted for publication to Physical Review

Suzaku measurement of Abell 2204's intracluster gas temperature profile out to 1800 kpc

Context: Measurements of intracluster gas temperatures out to large radii are important for the use of clusters for precision cosmology and for studies of cluster physics. Previous attempts to measure robust temperatures at cluster virial radii failed. Aims: The goal of this work is to measure the temperature profile of the very relaxed galaxy cluster Abell 2204 out to large radii, possibly reaching the virial radius. Methods: Taking advantage of its low particle background due to its low-Earth orbit, Suzaku data are used to measure the outer temperature profile of Abell 2204. These data are combined with Chandra and XMM-Newton data of the same cluster in order to make the connection to the inner regions, unresolved by Suzaku, and to determine the smearing due to Suzaku's PSF. Results: The temperature profile of Abell 2204 is determined from 10 kpc to 1800 kpc, close to an estimate of r200 (the approximation to the virial radius). The temperature rises steeply from below 4 keV in the very center up to more than 8 keV in the intermediate range and then decreases again to about 4 keV at the largest radii. Varying the measured particle background normalization artificially by +-10 percent does not change the results significantly. Predictions for outer temperature profiles based on hydrodynamic simulations show good agreement. In particular, we find the observed temperature profile to be slightly steeper but consistent with a drop of a factor of 0.6 from 0.3 r200 to r200, as predicted by simulations. Conclusions: Temperature measurements up to the virial radius seem feasible with Suzaku, when a careful analysis of the different background components and the effects of the PSF is performed. The result obtained here indicates that numerical simulations capture the intracluster gas physics well in cluster outskirts.Comment: 7 pages; Astronomy and Astrophysics, accepted; additional systematic effects have been quantified, results unchanged; also available at http://www.reiprich.ne