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We present here an experimental study of the influence of the aeroelastic coupling between the combustion chamber walls and the acoustic fluid field on the onset and development of thermoacoustic instabilities in stoichiometric propane-air premixed flames. A horizontal quasi-two-dimensional Hele–Shaw chamber formed by two parallel plates separated a small distance h is used. The flames are ignited at the open end, in contact with the atmosphere, and propagate towards the opposite closed end. The experiments reveal three distinct propagation regimes determined by the stiffness of the plates and the evolution of the pressure perturbation generated during ignition: (i) for sufficiently rigid plates, we observed secondary acoustic instabilities with large amplitude oscillations in the direction of propagation of the flame; for flexible enough walls to be compliant with ignition-related pressure changes, (ii) the propagation of the flame undergoes small-amplitude oscillations (primary acoustic instabilities) along the channel or (iii) it is smooth with no oscillations whatsoever. The flexural rigidity of the plate is modified experimentally by changing both the width W and thickness h w of the top plate of the Hele–Shaw cell. The data recorded by the pressure transducer and the accelerometer is used to plot a stability map in the W − h w parametric space to define the combination of structural parameters that triggers the onset of thermoacoustic instabilities. Our experimental measurements, supplemented with results from a theoretical analysis of the walls vibration modes, indicated that deformation-induced volume changes of around 0.1% of the volume of the Hele–Shaw cell are sufficient to suppress thermoacoustic instabilities. [ABSTRACT FROM AUTHOR]

In this paper, we study the effect of gravity, or buoyancy forces, on the structure of flames propagating in horizontal channels. It is shown that there are two mechanisms for the appearance of non-symmetric flames. The first, more obvious, is related to buoyancy, when a hotter gas of lower density tends to be located in the upper half of the channel. However, there is a second mechanism associated with the intrinsic flame instabilities, which also can cause the loss of flame symmetry. This mechanism can, at certain values of the parameters, act in the opposite direction, when hotter gases are enclosed in the lower part of the channel. In this case, two stable non-symmetric solutions may exist in the presence of gravitational forces and the establishment of one or another configuration depends on the initial conditions. The stability of these solutions is demonstrated by time-dependent computations. [ABSTRACT FROM AUTHOR]

In this work, a computational study on nearly two-dimensional reacting fronts under canonical configurations is proposed. Specifically, a quasi-2D description of the conservation equations with a one-step irreversible Arrhenius chemical model is used to simulate ultra-lean hydrogen-air premixed flames that slowly propagate over streams of reactants that are confined between plates and are subject to conductive heat losses. Under these conditions, recent previous experiments identified two unprecedented stable flame configurations: two-headed and circular isolated flames. This study identified buoyancy and the relative importance of conductive heat losses as the two parameters controlling the formation of these isolated flames. The numerical evaluation of the different terms ascertains the physical mechanisms that drive the formation of two-headed or circular flames. Additionally, the systematic variation of the controlling parameters depicts the maps of stable solutions that determine the capability of the two flame configurations to emerge. In particular, the existence of a range of parametric values in which both flame configurations are stable proves, also, that initial conditions are crucial to determine which of the two configurations prevails. [ABSTRACT FROM AUTHOR]

Copyright of Revista Catalana de Dret Ambiental is the property of Universitat Rovira I Virgili and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Catalana de Dret Ambiental is the property of Universitat Rovira I Virgili and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Human Review is the property of Eagora Science and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Prepolarized MRI (PMRI) is a long‐established technique conceived to counteract the loss in signal‐to‐noise ratio (SNR) inherent to low‐field MRI systems. When it comes to hard biological tissues and solid‐state matter, PMRI is severely restricted by their ultra‐short characteristic relaxation times. Here we demonstrate that efficient hard‐tissue prepolarization is within reach with a special‐purpose 0.26 T scanner designed for ex vivo dental MRI and equipped with suitable high‐power electronics. We have characterized the performance of a 0.5 T prepolarizer module, which can be switched on and off in 200 μs. To this end, we have used resin, dental and bone samples, all with T1 times of the order of 20 ms at our field strength. The measured SNR enhancement is in good agreement with a simple theoretical model, and deviations in extreme regimes can be attributed to mechanical vibrations due to the magnetic interaction between the prepolarization and main magnets. [ABSTRACT FROM AUTHOR]

A common recommendation when designing for disassembly is to develop more modular products. The common belief is that an increase in modularity will systematically reduce the time required in order to disassemble the product, reducing the cost of the process. This paper studies the statistical relationship between these two concepts by comparing 15 different electrical products. Modularity and disassembly performance are assessed by different indicators each and their correlation is analyzed. The results show that the aforementioned relationship cannot be statistically proven and, for some of the cases, even inverse correlation is found. Factors such as product structure or selected end-of-life strategy are more important than modularity in end-of-life performance. Systematic modularization can even result in products with a worse behavior: For most electrical equipment, generating modules from a functional or manufacturing point of view will most probably result in worse end-of-life performance. It is only for modules with very specific properties that performance can be guaranteed. [DOI: 10.1115/1.4000641] Keywords: product development, design theory and methodology, multiobjective optimization, systems engineering, fasteners

The paper focus on rare diseases as a challenge to the Welfare State, particularly for the effectiveness of the right to health protection; a situation derived from the scientific uncertainty, intensifying the budgetary restrictions, but which can improve thanks to technological progress, specifically big data (studies). In order to find some legal remedy, the work deeps in the application of the notion of human dignity as a pillar of the human rights and all the public intervention in the Society; an option that seems conceptually clearer in Spain than in the European Union legal system. Particularly, given the framework of competences applicable in matters of public health and the controversial nature of the notion of human dignity. Finally, it is verified that the use of this notion is not fully supported by Spanish jurisprudence either. [ABSTRACT FROM AUTHOR]

Use of interleukin (IL-6) inhibitors has become one of the most complicated clinical issues in treating coronavirus disease 2019 (COVID-19). Recently, randomized open-label platform trials have found that IL-6 inhibitors have a beneficial effect on mortality in severe COVID-19. However, several questions arise around their mechanism of action in this disease, as well as how, when, and at which dose they should be used. IL-6 has both proinflammatory and anti-inflammatory effects, which may modulate the course of COVID-19, whose immunopathogenesis is driven by the innate immune system, autoantibodies, and interferon. Given that patients with delayed seroconversion against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein would be at the highest risk of complications beyond the second week of disease, we propose that considering patient serostatus at admission could optimize the use of IL-6 inhibitors in COVID-19. We predict that the net treatment benefits could be higher in the subgroup of patients with delayed seroconversion as compared to those who seroconvert more rapidly after SARS-CoV-2 infection. [ABSTRACT FROM AUTHOR]

Copyright of Revista Catalana de Dret Ambiental is the property of Universitat Rovira I Virgili and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Catalana de Dret Ambiental is the property of Universitat Rovira I Virgili and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Today's society faces great global challenges, but none more pressing than eradicating the inequalities that are present everywhere on the planet. The effort being made by the international community with the implementation of the Sustainable Development Goals (SDGs) is notorious. Education, in this global context, becomes one of the essential instruments that will allow a solution to these new challenges. The University, from its three main functions, teaching, research and innovation, must play a key role in leading social change in this regard. SDG 4, under the rubric of "quality education", poses a tremendously ambitious challenge: to ensure inclusive and equitable quality education and promote lifelong learning opportunities for all. This lofty aspirational goal focuses its efforts on minimum targets to alleviate the enormous global inequalities in education. From this perspective, it ties in with other sustainable development goals such as ending poverty (SDG 1) or gender equality (SDG 5). Formal education is essential to change people's attitudes and to train them in a critical awareness that enables them to assess the problems, address them and use the necessary tools to reverse them. In this research, the work carried out by the Department of Social Practices of the Francisco de Vitoria University, promoting inclusive, sustainable and egalitarian education through the active participation of students in their own learning, is presented and analysed. The results obtained show that comprehensive training and the implementation of activities in vulnerable social contexts improve students' commitment to society, while they are trained in plurality, diversity and multiculturalism. [ABSTRACT FROM AUTHOR]

Copyright of Revista de Estudios de la Administración Local y Autonómica is the property of Instituto Nacional de Administracion Publica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Deleterious mutations continuously accumulate in populations, building up a burden that can threaten their survival, particularly in small populations when inbreeding exposes recessive deleterious effects. Notwithstanding, this process also triggers genetic purging, which can reduce the deleterious burden and mitigate fitness inbreeding depression. Here, we analyzed 20 whole genomes from the endangered Iberian lynx and 28 from the widespread Eurasian lynx, sister species which constitute a good model to study the dynamics of deleterious mutation burden under contrasting demographies, manifested in the consistently smaller population size and distribution area of the Iberian lynx. We also derived analytical predictions for the evolution of the deleterious burden following a bottleneck. We found 11% fewer derived alleles for the more putatively deleterious missense category in the Iberian lynx than in the Eurasian lynx, which, in light of our theoretical predictions, should be ascribed to historical purging. No signs of purging were found in centromeres nor in the X chromosome, where selection against recessive deleterious alleles is less affected by demography. The similar deleterious burden levels for conspecific populations despite their contrasting recent demographies also point to sustained differences in historical population sizes since species divergence as the main driver of the augmented purging in the Iberian lynx. Beyond adding to the ongoing debate on the relationship between deleterious burden and population size, and on the impact of genetic factors in endangered species viability, this work contributes a whole-genome catalog of deleterious variants, which may become a valuable resource for future conservation efforts. [ABSTRACT FROM AUTHOR]

This study investigated experts' understanding of sports clothing quality, the quality attributes they consider, and their views on the evaluation process. Twenty-two experts working in different sports clothing development and evaluation functions participated in semi-structured expert interviews. A thematic analysis highlighted three different views on quality, real-world problems in the evaluation process, and facilitated a sports clothing quality framework. Experts saw sports clothing quality as the fulfilment of use-case requirements, an immediate impression, or an individual perception. With the established sports clothing quality framework, it was possible to break down the overall quality impression in attributes and assign evaluation methods to it. Several challenges and suggestions for the evaluation process were detected. This ranged from the lack of measurability of attributes to solutions such as digitalisation. [ABSTRACT FROM AUTHOR]

This paper presents an experimental study of the influence of heat losses on the onset of thermoacoustic instabilities in methane-air premixed flames propagating in a horizontal tube of diameter, D = 10 mm. Flames are ignited at the open end of the tube and propagate towards the closed end undergoing strong oscillations of different features owing to the interaction with acoustic waves. The frequency of oscillation and its axial location are controlled through the tube length L and the intensity of heat losses. These parameters are respectively modified in the experiments by a moveable piston and a circulating thermal bath of water prescribing temperature conditions. Main experimental observations show that classical one-dimensional predictions of the oscillation frequency do not accurately describe the phenomena under non-adiabatic real scenarios. In addition to the experimental measurements, a quasi-one-dimensional analysis of the burnt gases is provided, which introduces the effect of heat losses at the wall of the tube on the interplay between the acoustic field and the reaction sheet. As a result, this analysis provides an improved description of the interaction and accurately predicts the excited flame-oscillation harmonics through the eigenvalues of the non-adiabatic acoustics model. Unlike the original one-dimensional analysis, the comparison between the flame oscillation frequency provided by the non-adiabatic extended theory and the frequencies measured in our experiments is in excellent agreement in the whole range of temperatures considered. This confirms the importance of heat losses in the modulation of the instabilities and the transition between different flame oscillation regimes. [ABSTRACT FROM AUTHOR]

We present a magnet and high-power electronics for prepolarized magnetic resonance imaging (PMRI) in a homemade, special-purpose preclinical system designed for simultaneous visualization of hard and soft biological tissues. The sensitivity of magnetic resonance imaging (MRI) systems grows with field strength, but so do their costs. PMRI can boost the signal-to-noise ratio (SNR) in affordable low-field scanners by means of a long and strong magnetic pulse. However, this must be rapidly switched off prior to the imaging pulse sequence, in timescales shorter than the spin relaxation (or $T_{1}$) time of the sample. We have operated our prepolarizer at up to 0.5 T and demonstrated enhanced magnetization, image SNR, and tissue contrast with PMRI of tap water and an ex vivo mouse brain and food samples. These have $T_{1}$ times ranging from hundreds of milli-seconds to single seconds, while the preliminary high-power electronics setup employed in this work can switch off the prepolarization field in tens of milli-seconds. In order to make this system suitable for solid-state matter and hard tissues, which feature $T_{1}$ times as short as 10 ms, we are developing new electronics, which can cut switching times to $\sim {300} {\mu{\mathrm {s}}}$. This does not require changes in the prepolarizer module, opening the door to the first experimental demonstration of PMRI on hard biological tissues. [ABSTRACT FROM AUTHOR]

Stratosphere–troposphere exchange (STE) is an important source of tropospheric ozone, affecting all of atmospheric chemistry, climate, and air quality. The study of impacts needs STE fluxes to be resolved by latitude and month, and for this, we rely on global chemistry models, whose results diverge greatly. Overall, we lack guidance from model–measurement metrics that inform us about processes and patterns related to the STE flux of ozone (O 3). In this work, we use modeled tracers (N 2 O and CFCl 3), whose distributions and budgets can be constrained by satellite and surface observations, allowing us to follow stratospheric signals across the tropopause. The satellite-derived photochemical loss of N 2 O on annual and quasi-biennial cycles can be matched by the models. The STE flux of N 2 O-depleted air in our chemistry transport model drives surface variability that closely matches observed fluctuations on both annual and quasi-biennial cycles, confirming the modeled flux. The observed tracer correlations between N 2 O and O 3 in the lowermost stratosphere provide a hemispheric scaling of the N 2 O STE flux to that of O 3. For N 2 O and CFCl 3 , we model greater southern hemispheric STE fluxes, a result supported by some metrics, but counter to the prevailing theory of wave-driven stratospheric circulation. The STE flux of O 3 , however, is predominantly northern hemispheric, but evidence shows that this is caused by the Antarctic ozone hole reducing southern hemispheric O 3 STE by 14 %. Our best estimate of the current STE O 3 flux based on a range of constraints is 400 Tg(O 3) yr -1 , with a 1σ uncertainty of ± 15 % and with a NH : SH ratio ranging from 50:50 to 60:40. We identify a range of observational metrics that can better constrain the modeled STE O 3 flux in future assessments. [ABSTRACT FROM AUTHOR]