Numerical study of the aerodynamics of sound sources in a bass-reflex port

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.The aim of this paper is to study the aerodynamics phenomena of a bass-reflex port that causes noise in the audible frequency range. After discarding structural and mechanical vibration issues, the hypothesis considered is that vortex shedding is the source of the noise. Experimental and numerical evidences of the vortex, an analysis of its noise and the similarities between real and simulated performance are presented. The numerically simulated cases with the original geometry are excited at different frequencies and with modifications of the port geometry. Likewise, the internal performance of an enclosure with a closed port was simulated. The simulations have been performed with axisymmetrical geometries using the open-source OpenFOAM® toolbox. Moreover, experimental measurements were carried out. First, acoustic signal experiments were done to analyse the response of the bass-reflex ports. Secondly, a structure vibration measurement was conducted in order to exclude the cabinet structure vibration as a source of the noise in question. A good agreement was found between numerical and experimental results, especially in the frequency band of the detected noise, i.e. the 1000–1500 Hz range. Despite no remarkable improvement being made with the geometry changes explored, the presented CFD approach has proved a useful and cost-effective tool to address this kind of phenomenon.Peer ReviewedPostprint (published version

El metabolismo social. Historia, métodos y principales aportaciones

El concepto de Metabolismo Social ha cobrado una gran importancia dentro de los estudios que tratan de comprender las interacciones entre la sociedad y el medio ambiente. Desde la década de 1990 su impacto ha crecido de manera exponencial siendo utilizado por numerosos autores provenientes de diferentes disciplinas científicas. El objetivo de este trabajo es ofrecer un estado de la cuestión de este enfoque. Se revisan los orígenes y la historia del concepto, su reciente éxito, las herramientas metodológicas que se han utilizado en el marco de sus estudios, así como los principales resultados que ha generado.El concepto de Metabolismo Social ha cobrado una gran importancia dentro de los estudios que tratan de comprender las interacciones entre la sociedad y el medio ambiente. Desde la década de 1990 su impacto ha crecido de manera exponencial siendo utilizado por numerosos autores provenientes de diferentes disciplinas científicas. El objetivo de este trabajo es ofrecer un estado de la cuestión de este enfoque. Se revisan los orígenes y la historia del concepto, su reciente éxito, las herramientas metodológicas que se han utilizado en el marco de sus estudios, así como los principales resultados que ha generado.El concepto de Metabolismo Social ha cobrado una gran importancia dentro de los estudios que tratan de comprender las interacciones entre la sociedad y el medio ambiente. Desde la década de 1990 su impacto ha crecido de manera exponencial siendo utilizado por numerosos autores provenientes de diferentes disciplinas científicas. El objetivo de este trabajo es ofrecer un estado de la cuestión de este enfoque. Se revisan los orígenes y la historia del concepto, su reciente éxito, las herramientas metodológicas que se han utilizado en el marco de sus estudios, así como los principales resultados que ha generado.The concept of Social Metabolism has gained a growing importance among the studies that try to understand human-nature interactions. Its impact has grown exponentially since the 1990s, being used by many authors representing different scientific disciplines. The main goal of this paper is to  provide a review of the state of the art concerning the social metabolism approach. We reconstruct the origins and history of the concept, its recent success, the methodological tools used and the principal findings it has generated

ESPRESSO: The next European exoplanet hunter

The acronym ESPRESSO stems for Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations; this instrument will be the next VLT high resolution spectrograph. The spectrograph will be installed at the Combined-Coud\'e Laboratory of the VLT and linked to the four 8.2 m Unit Telescopes (UT) through four optical Coud\'e trains. ESPRESSO will combine efficiency and extreme spectroscopic precision. ESPRESSO is foreseen to achieve a gain of two magnitudes with respect to its predecessor HARPS, and to improve the instrumental radial-velocity precision to reach the 10 cm/s level. It can be operated either with a single UT or with up to four UTs, enabling an additional gain in the latter mode. The incoherent combination of four telescopes and the extreme precision requirements called for many innovative design solutions while ensuring the technical heritage of the successful HARPS experience. ESPRESSO will allow to explore new frontiers in most domains of astrophysics that require precision and sensitivity. The main scientific drivers are the search and characterization of rocky exoplanets in the habitable zone of quiet, nearby G to M-dwarfs and the analysis of the variability of fundamental physical constants. The project passed the final design review in May 2013 and entered the manufacturing phase. ESPRESSO will be installed at the Paranal Observatory in 2016 and its operation is planned to start by the end of the same year.Comment: 12 pages, figures included, accepted for publication in Astron. Nach

Paraprofessionals in private preschools : how are they being prepared to include children with disabilities?

Qualitative research methods were used to examine the training needs of inclusion paraprofessionals employed at private preschools. Five qualifying preschool sites were located, and three individual interviews were conducted from one selected inclusion classroom setting at each site. Interviewees consisted of parents of children with disabilities, general education teachers, and inclusion paraprofessionals. Results indicated that inclusion paraprofessionals in the private sector might not be receiving adequate preparation for effective inclusion of preschool age children with disabilities. General education teachers in the same settings also stated feeling unprepared to meet the needs of young children with disabilities who are enrolled in their classrooms. There was a marked difference in training need perceptions between parents who were interviewed and inclusion paraprofessionals who worked with their children. Parents requested training for specific disabilities, while inclusion paraprofessionals requested training on behavior management, preschool curriculum, and strategies for effective inclusion of children with disabilities in typical preschool settings. Implications indicate a reform in policy for teacher and paraprofessional preparation programs to meet the demands of the growing population of children with disabilities who are being enrolled in typical private preschool settings.California State University, Northridge. Department of Education.Includes bibliographical references (leaves 68-76

El metabolismo social : historia, métodos y principales aportaciones

El concepto de Metabolismo Social ha cobrado una gran importancia dentro de los estudios que tratan de comprender las interacciones entre la sociedad y el medio ambiente. Desde la década de 1990 su impacto ha crecido de manera exponencial siendo utilizado por numerosos autores provenientes de diferentes disciplinas científicas. El objetivo de este trabajo es ofrecer un estado de la cuestión de este enfoque. Se revisan los orígenes y la historia del concepto, su reciente éxito, las herramientas metodológicas que se han utilizado en el marco de sus estudios, así como los principales resultados que ha generado.The concept of Social Metabolism has gained a growing importance among the studies that try to understand human-nature interactions. Its impact has grown exponentially since the 1990s, being used by many authors representing different scientific disciplines. The main goal of this paper is to  provide a review of the state of the art concerning the social metabolism approach. We reconstruct the origins and history of the concept, its recent success, the methodological tools used and the principal findings it has generated

Towards an integrated evaluation framework for xai: an experimental study

Increasing prevalence of opaque black-box AI has highlighted the need for explanations of their behaviours, for example, via explanation artefacts/proxy models. The current paper presents a paradigm for human-grounded experiments to evaluate the relationship between explanation fidelity, human learning performance, understanding and trust in a black-box AI by manipulating the complexity of an explanatory artefact. Decision trees were used in the current experiment as exemplar interpretable surrogate models, providing explanations approximating black-box behaviour, by means of explanation by simplification. Consistent with our hypotheses: 1) explanatory artefacts brought about better learning, while greater decision tree depths led to greater interpretability of the AI's performance and greater trust in the AI; and 2) explanatory artefacts facilitated learning and task performance even after they were withdrawn. Findings are discussed in terms of the interplay between human understanding, trust and AI system performance, highlighting the simplifying assumption of a monotonic relationship between explanation fidelity and interpretability

Case Report: Localized bullous pemphigoid induced by local triggers: a case series and a proposal for diagnostic criteria based on a literature review

IntroductionLocalized bullous pemphigoid (LBP) is an infrequent bullous pemphigoid (BP) variant restricted to a body region. According to the most compelling evidence, LBP occurs in patients with pre-existent serum antibodies against the basement membrane zone, which occasionally acquire the capacity to induce disease after the influence of different local factors acting as triggers.MethodsWe hereby present a multicenter cohort of 7 patients with LBP developed after local triggers: radiotherapy, thermal burns, surgery, rosacea, edema and a paretic leg. In addition, we conducted a review of the literature, and we propose a set of diagnostic criteria for LBP, also based on our case series and the 2022 BP guidelines from the European Academy of Dermatology and Venereology.ResultsDuring follow-up, three of the patients from our series evolved to a generalized BP, with only one requiring hospitalization. Our literature search retrieved 47 articles including a total of 108 patients with LBP, with a 63% with a potential local precipitating factor previous to their diagnosis. LBP mostly affected older females, and a subsequent generalized progression occurred in 16.7% of the cases. The most frequently involved areas were the lower limbs. Radiation therapy and surgery were responsible for the inducement of nearly 2 in 3 cases of LBP. We observed a significantly higher risk of generalization in cases where the trigger led to the developing of LBP earlier (p=0.016). Our statistical analysis did not detect any other prognosis factor for generalization when assessing direct immunofluorescence, histological and serological results, or other patient related factors.ConclusionLBP should be suspected in patients with recurrent localized bullous eruptions. The presence of a trauma history in the same anatomic area is reported in most cases