616 research outputs found

    On the Low-Frequency Dynamics of Turbulent Separation Bubbles

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    The low-frequency modal and non-modal stability characteristics of an incompressible, pressure-gradient-induced turbulent separation bubble (TSB) are investigated with the objective of studying the mechanism responsible for the low-frequency contraction and expansion (breathing) commonly observed in experimental studies. The configuration of interest is a TSB generated on a flat test surface by a succession of adverse and favourable pressure gradients. The base flow selected for the analysis is the average TSB from the direct numerical simulation of Coleman et al. (J. Fluid Mech., vol. 847, 2018). Global linear stability analysis reveals that the flow is globally stable for wavenumbers. The mode closest to the stability threshold appears to occur at zero frequency and low, non-zero spanwise wavenumber. Resolvent analysis is then employed to examine the forced dynamics of the flow. At low frequency, a region of low, non-zero spanwise wavenumber is also discernible, where the receptivity appears to be driven by the identified weakly damped global mode. The results from resolvent analysis are compared to the unsteady experimental database of Le Floc'h et al. (J. Fluid Mech., vol. 902, 2020) in a similar TSB flow. The alignment between the optimal response and the first spectral proper orthogonal decomposition mode computed from the experiments is shown to exceed 95 %, while the spanwise wavenumber of the optimal response is consistent with that of the low-frequency breathing motion captured experimentally. This indicates that the fluctuations observed experimentally at low frequency closely match the response computed from resolvent analysis. Based on these results, we propose that the forced dynamics of the flow, driven by the weakly damped global mode, serve as a plausible mechanism for the origin of the low-frequency breathing motion commonly observed in experimental studies of TSBs

    La riforma dei servizi ispettivi in materia di lavoro e previdenza sociale. Commentario al decreto legislativo 23 aprile 2004, n. 124

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    Il presente volume nasce dalla volontà di contribuire alla diffusione dei contenuti di una riforma – quella dei servizi ispettivi e delle attività di vigilanza prevista dal d.lgs. n. 124/2004 – di cui ancora troppo poco si parla e discute, e che pure potrebbe risultare decisiva per il progetto di modernizzazione del nostro mercato del lavoro delineato con la c.d. legge Biagi. L’effettività delle regole del diritto del lavoro è, in effetti, la condizione primaria per una più efficiente tutela dei diritti dei lavoratori e, al tempo stesso, è anche garanzia di leale competizione tra le imprese

    Apprendistato: quadro comparato e buone prassi

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    Il volume affronta da un punto di vista comparato gli aspetti principali connessi al contratto di apprendistato. Il punto di partenza sono le analisi e gli spunti offerti dalle istituzioni comunitarie per una maggiore diffusione dei rapporti di apprendistato, in un’ottica di aumento dell’occupazione giovanile e di contrasto alla dispersione scolastica. La pubblicazione mette in relazione cinque aspetti: definizione e ruolo dell’apprendistato; soggetti regolatori; retribuzione; durata del percorso; monte ore formativo. Per ciascuna di queste voci si evidenziano le peculiarità dei sistemi in vigore in Italia, Francia, Spagna, Regno Unito, Germania, Danimarca e Svezia

    Los mármoles comerciales “Marrón Imperial” y “Marrón Emperador” (S.E. España). Caracterización petrológica y criterios de exploración

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    Los mármoles comerciales "Marrón Imperial" y "Marrón Emperador" son dolomías brechoides que de acuerdo con la clasificación del MIA pertenece al Grupo C de mármoles comerciales. Se determinan sus parámetros petrofísicos según la norma UNE. Sus rasgos petrológicos se estudian mediante microscopio petrográfico de luz transmitida y microscopio electrónico de barrido (MEB) (en modo de electrones secundarios y electrones retrodispersados). Estas rocas son básicamente dolomías mesocristalinas con abundantes vénulas calcíticas politexturales relacionadas con procesos de brechificación y de dolomitización. Rasgos kársticos aumentan la complejidad petrológica de estas rocas ornamentales cuyo litosoma son las dolomías masivas del Cretácico Superior (¿Turoniense?) del dominio Prebético Externo. El material explotado pertenece a una alineación morfoestructural que va desde Jumilla hasta el NE de Caudete y está relacionado con la falla Jumilla-Yecla-Caudete-Font de la Figuera. La relación entre esta falla y las dolomías turonienses son el principal criterio de exploración de estas rocas ornamentales.The "Marrón Imperial" and the "Marrón Emperador" commercial marble are brecciated dolomite rocks that, in agree with the soundness classification of MIA, belongs to the Group C of the commercial marbles. Petrophysical parameters of stones has been obtained using de UNE NORM (Spanish normalised test). The petrologic features have been defined from light microscopy and SEM data (secondary electrons and back scattered electrons modes). "Marrón Imperial" and "Marrón Emperador" are mesocrystalline dolostones with a reticulate of calcite veins, which are polytextural and are related to both brecciation and dedolomitization processes. Karstic features increase the petrologic complexity of this dimensional stone. The host lithosomes of "Marrón Imperial" and "Marrón Emperador" marbles are the massive dolostones of Upper Cretaceous (Turonian?) age of Outer Prebetic Domain. The quarried material outcrops from Jumilla to NE Caudete; Villena-La Encina, Jumilla (Fuente and Cingla Mountains) Yecla (Magdalena Mountains). Caudete and Yecla are the most important areas for extraction at the moment. The tectofacies that are the main responsible of the aesthetic properties of the Marrón Imperial and Marrón Emperador commercial marbles which main outcrops are probably related to the Jumilla-Yecla-Caudete-Font de la Figuera near strike-slip fault and associated events. The main exploration criteria from this type of commercial marble are the fault line distribution, and their influence over Turonian dolostones.Este trabajo forma parte del Proyecto AMB 93-0019 subvencionado por la CICYT

    Real world data in primary care: validation of diagnosis of atrial fibrillation in primary care electronic medical records and estimated prevalence among consulting patients

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    Primary care electronic medical records contain clinical-administrative information on a high percentage of the population. Before this information can be used for epidemiological purposes, its quality must be verified. This study aims to validate diagnoses of atrial fibrillation (AF) recorded in primary care electronic medical records and to estimate the prevalence of AF in the population attending primary care consultations. Methods: We performed a cross-sectional validation study of all diagnoses of AF recorded in primary care electronic medical records in Madrid (Spain). We also performed simple random sampling of diagnoses of AF (ICPC-2 code K78) registered by 55 physicians and random age- and sex-matched sampling of the records that included a diagnosis of AF. Electrocardiograms, echocardiograms, and hospital discharge or cardiology clinic reports were matched. Sensitivity, specificity, positive and negative predictive values (PPV and NPV), and overall agreement were calculated using the kappa statistic (κ). The prevalence of AF in the community of Madrid was estimated considering the sensitivity and specificity obtained in the validation. All calculations were performed overall and by sex and age groups. Results: The degree of agreement was very high (κ = 0.952), with a sensitivity of 97.84%, specificity of 97.39%, PPV of 97.37%, and NPV of 97.85%. The prevalence of AF in the population aged over 18 years was 2.41% (95%CI 2.39–2.42% [2.25% in women and 2.58% in men]). This increased progressively with age, reaching 16.95% in those over 80 years of age (15.5% in women and 19.44% in men). Conclusions: The validation results obtained enable diagnosis of AF recorded in primary care to be used as a tool for epidemiological studies. A high prevalence of AF was found, especially in older patientsThis study forms part of research funded by the FIS (Fondo de Investigaciones Sanitarias—Health Research Fund, Instituto de Salud Carlos III) grants no. PI13/00632, and co-funded by the European Union through the Fondo Europeo de Desarrollo Regional (FEDER, “A way of shaping Europe”. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

    Geodiversidad mineralógica y petrológica del diapiro de Pinoso y su interés como patrimonio geológico

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    El diapiro de Pinoso, también denominado Cerro o Cabeҫo de la Sal, está situado al W de la provincia de Alicante, (38º24’ N- 01º02”O), de forma elíptica con eje mayor (NW-SE) de 7,5 km y altura máxima de 893 m, 350 m por encima de la superficie erosiva colindante. Constituido por materiales de facies Keuper, presenta un núcleo de halita que ha sido objeto de explotación, tanto por minería subterránea como por evaporación (extracción y comercialización de sal manantial). También, a principios del siglo XX, aguas procedentes del Cabeҫo fueron utilizadas en un balneario, previo calentamiento del agua. Desde 1973 se explota por disolución y la salmuera extraída es llevada a Torrevieja mediante un salmueroducto y allí pasa a formar parte del proceso de evaporación de explotación de las salinas. La variedad de las litologías presentes en él, así como su riqueza en patrimonio mineral mueble, algunos de los cuales son minerales autigénicos característicos de las facies Keuper, confieren al Cabeҫo de la Sal un notable valor como Patrimonio Geológico, este carácter patrimonial se ve aumentado por los rasgos geomorfológicos asociados al exokarst en materiales yesíferos hipergénicos que genera formas erosivas cualitativa y cuantitativamente muy importantes
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