62 research outputs found
Episyenites within the Tauern Window metagranitoids: unpredictable?
The core of the Tauern tectonic window (Eastern Alps) consists of dominant pre-Alpine granitoids (⌠295 Ma) that were metamorphosed and deformed during the Alpine orogenesis (at ⌠30 Ma). Ductile deformation at peak conditions (550-600 ÌC and 0.5-0.7 GPa) was followed by cataclastic faulting (Pennacchioni and Mancktelow, 2007). Both deformation phases occurred in a fluid-rich environment with formation of veins filled with quartz-calcite-biotite-feldspar and quartz-chlorite-epidote-adularia-calcite, respectively. Faults are typically low displacement strike-slip structures (offset < 1m) organized in en-echelon arrays at different scales with a stepping geometry consistent with the sense of fault slip (e.g. left-stepping for dextral slip). Fault stepovers include pervasive fracturing dominated by a set of antithetic faults (Pennacchioni and Mancktelow, 2013). These faults were locally exploited by episyenitic alteration which represented the "last" event of fluid-rock interaction in the Tauern meta-granitoids. Episyenites within metagranodiorites have a macroscopic porosity in the range between 25 and 35% volume (determined by microtomography), mostly derived from dissolution of multi-mm-sized quartz. Recent glacier-polished outcrops provide a unique opportunity to investigate the relationships between episyenites and overprinted faults. Detailed field mapping of a selected outcrop indicates that episyenites: (i) are spatially linked to precursor faults and statically overprinted all previous structures; (ii) occur discontinuously along faults; (iii) have a thickness (of as much as a few meters) that does not correlate with either the amount of fault slip or the density of the fracture network; (iv) developed independently of rock type (passing "undisturbed" lithologic boundaries with conspicuous variations of quartz grain size of the protolith lithology). Although the faults in the studied outcrop are extensively decorated by relatively large volumes of episyenite, occurrences of episyenite in the Tauern granitoids are generally rare. This study indicates that there is not a simple way to predict the location and the extent of episyenite alteration from the geometry and fracturing patterns of the network of precursor cataclastic faults. The dominant quartz dissolution during episyenitization was accompanied and/or followed by: (i) pervasive substitution of oligoclase and chlorite/biotite of the metagranodiorite by albite and clay-minerals, respectively, and (ii) limited precipitation of new adularia, anatase, calcite, hematite and zeolite within pores. Isotopic data from calcite filling the episyenite porosity suggest a meteoric source of the fluids (ÎŽ18 O (SMOW) â -2 per mil). In contrast, fluids synkinematic with previous episodes of fluid-rock interaction during faulting and ductile shearing had a deeper origin (ÎŽ18O (SMOW) â 8-9 per mil). References Pennacchioni, G., Mancktelow, N.S., 2007. J. Struct. Geol. 29, 1757-1780. Pennacchioni, G., Mancktelow, N.S., 2013. Geol. Soc. Am. Bull. 125, 1468-1483
Soluble collagen dissolution and assembling in pressurized carbon dioxide water solutions
Dissolution and gelation procedures have a great influence on gelation time, microstructure and mechanical properties of reconstituted collagen products. We have investigated the dissolution of atelocollagen in CO2/water solutions at low temperature (4 degrees C) at different CO2 pressures (0.3-0.9 MPa), as well as gelation kinetics and physico-chemical properties of the hydrogel obtained after CO2 removal. Compared to conventional methods, the CO2-assisted technique resulted in faster soluble collagen dissolution and faster gelation into transparent gels characterized by thin 10 nm fibrils. Electrophoresis and CD spectroscopy demonstrated that the process did not denature the soluble collagen. The possibility to obtain collagen dissolution and gelation without the use of chemical agent other than water and CO2 makes this process particularly appealing for biomedical applications
Alongamento no Programa de Atividade FĂsica para Terceira Idade (PROFIT): promovendo a melhora da capacidade funcional em idosas
Several studies have reported physical and psychosocial benefi ts of regular physical activity.Stretching exercises, once they are easy to apply and learn, become a simple and effective way to improve functionalcapacity and quality of life of elderly individuals. In 2009 was created an activity within the extensionproject Physical Activity Program for Elderly (PROFIT), called Stretching group. It aims to present the technical/administrative organizational aspects involved in implementing a stretching group within the university extensionproject and to illustrate the applicability of this type of intervention in the elderly. The group is directed towardwomen, aged 60 years or older who do not engage in systematic physical activity. Due to the support provided bythe university and the ease understanding and applicability of the exercises performed in the stretching group, itseems to be a relatively simple alternative to be implemented within a university extension project. In addition,there was a positive change in the Global functional fi tness index (IAFG) of elderly participants. Thus, the implementationof other groups in different places should be encouraged. It is noteworthy that the multidisciplinaryparticipation in health (physiotherapists, occupational therapists, psychologists, etc.) would enrich the benefi tsprovided by this type of intervention for the elderly.Diversos estudos tĂȘm apresentado os benefĂcios fĂsicos e psicossociais da prĂĄtica regularde atividade fĂsica. ExercĂcios de alongamento, por serem de fĂĄcil aplicação e aprendizagem,tornam-se uma opção simples e efi caz na melhora da capacidade funcional e qualidade de vida deindivĂduos idosos. Em 2009 foi criada uma atividade dentro do projeto de extensĂŁo Programa deAtividade FĂsica para Terceira Idade (PROFIT), o Grupo de alongamento. Objetiva-se apresentaros aspectos organizacionais tĂ©cnico/administrativos envolvidos na implementação de um grupode alongamento em um projeto de extensĂŁo universitĂĄria e exemplifi car a aplicabilidade deste tipode intervenção, em idosos. O grupo Ă© voltado para mulheres, com 60 anos ou mais que nĂŁo pratiquematividade fĂsica sistematizada. Devido ao apoio fornecido pela universidade e a facilidade decompreensĂŁo e aplicabilidade dos exercĂcios realizados no grupo de alongamento, este surge comouma alternativa relativamente simples a ser implantada em um projeto de extensĂŁo universitĂĄria.AlĂ©m disso, observou-se uma alteração positiva no Ăndice de aptidĂŁo funcional geral (IAFG) dasidosas participantes. Dessa forma a implementação de outros grupos, em diferentes locais deve serincentivada. Vale ressaltar que a participação multidisciplinar em saĂșde (fi sioterapeutas, terapeutasocupacionais, psicĂłlogos, etc) enriqueceria ainda mais os benefĂcios proporcionados por esse tipode intervenção para indivĂduos idosos
Allelic Variants of ARMC5 in Patients With Adrenal Incidentalomas and in Patients With Cushing's Syndrome Associated With Bilateral Adrenal Nodules
COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study
Background:
The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms.
Methods:
International, prospective observational study of 60â109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms.
Results:
âTypicalâ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (â€â18 years: 69, 48, 23; 85%), older adults (â„â70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each Pâ<â0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country.
Interpretation:
This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men
Forme dell\u2019identit\ue0 multiculturale adolescenziale femminile. Una ricerca sulle scuole medie superiori
Il saggio illustra i risultati di una ricerca, realizzata nelle scuole medie superiori che ha coinvolto delle adolescenti, immigrate di prima generazione, di seconda generazione (con i genitori stranieri e nate o trasferite dalla primissima infanzia in Italia) e bi-culturali (con un genitore straniero). Le adolescenti coinvolte provengono da aree geografiche con culture diverse da quella italiana (paesi islamici dell\u2019Africa settentrionale e del Medio Oriente, Europa orientale, Africa centrale, Estremo oriente). Attraverso l\u2019uso di strumenti qualitativi (interviste semistrutturate audioregistrate), la ricerca ha permesso di analizzare i modi di costruzione sociale e le forme risultanti dell\u2019identit\ue0 multiculturale adolescenziale femminile nella comunicazione interculturale con riferimento alle dinamiche di inclusione ed esclusione. L\u2019esclusione sociale si dimostra poco rilevante nel sistema educativo, con l\u2019eccezione parziale dell\u2019esperienza della scuola media inferiore, ma in tale sistema le adolescenti osservano diffusi stereotipi e pregiudizi nei confronti delle loro culture di origine. Nel gruppo amicale, le relazioni sono considerate positivamente, ma si osserva anche una diffusa superficialit\ue0 nelle comunicazioni interculturali, basata su pregiudizi e stereotipi, che si accompagna ad un processo di auto-esclusione, determinato dalle condizioni familiari, pi\uf9 restrittive di quelle subite dalle coetanee. L\u2019auto-esclusione concerne anche i rapporti sentimentali, mentre nei confronti della famiglia di origine si produce ambivalenza, molto pi\uf9 spesso che scontro o adesione. L\u2019inclusione in comunit\ue0 religiose ed etniche \ue8 diffusa soltanto tra le ragazze di prima generazione, mentre i legami con i paesi di origine, soprattutto con la famiglia allargata, vengono generalmente mantenuti. Per questo insieme di aspetti, nonostante la scarsa frequentazione di comunit\ue0 esclusive, le ragazze si considerano culturalmente diverse dalle coetanee italiane e vivono un\u2019inclusione sociale ambivalente.Questa doppia tendenza \ue8 confermata dal fatto che, nonostante l\u2019ampia diffusione di prospettive personalizzate accompagnate dal senso di autonomia rispetto alle culture di origine, il senso di appartenenza culturale \ue8 considerato rilevante da quasi tutte le adolescenti. Tra le ragazze bi-culturali, prevale un\u2019assimilazione all\u2019identit\ue0 culturale italiana venata da ambivalenze che portano ad un\u2019auto-osservazione di diversit\ue0. Le ragazze di prima generazione assumono prospettive differenziate: assimilazione senza rinnegare le origini culturali, identit\ue0 culturale originaria, anche con tendenza all\u2019auto-esclusione, prospettiva tendenzialmente cosmopolita che porta a tagliare le radici culturali e a creare una cittadinanza globale. Le adolescenti di seconda generazione dichiarano un\u2019affiliazione paradossale problematica (doppia appartenenza, senza integrazione in un\u2019identit\ue0 unitaria transculturale), oppure una doppia negazione dell\u2019identit\ue0 culturale, che produce un senso di smarrimento rispetto all\u2019anelito all\u2019appartenenza e finisce col portare verso un forzato modernismo cosmopolita. L\u2019intento comunicativo nei confronti della diversit\ue0 \ue8 legato ad una preferenza generalizzata per la condivisione transculturale dei valori realizzata attraverso il dialogo, soprattutto tra le adolescenti bi-culturali e di seconda generazione, oppure una prospettiva modernista ed insieme etnocentrica, caratterizzata dalla tolleranza, soprattutto tra le adolescenti di prima generazione e biculturali.In sintesi, la ricerca evidenzia che: 1) la variet\ue0 delle forme di identit\ue0 culturale non \ue8 riconducibile ai modelli presentati in letteratura (la stessa idea di \u201cmeticciato\u201d appare insufficiente); 2) le ambivalenze segnano fortemente le forme dell\u2019identit\ue0 culturale, rendendo quest\u2019ultima problematica, sia per la costruzione di un\u2019identit\ue0 personale, sia per la comunicazione interculturale
Solid-fluid Transition in Granular Flows: MPM Simulations with a New Constitutive Approach
Many natural phenomena (rock or snow avalanches, and debris flows) as well as industrial processes are characterized by the flow of solid particles. A key issue in the development of a numerical tool for the study of this problem is the implementation of a suitable constitutive model, capable of capturing the complex rheological behaviour of the granular material in a wide range of strain rates. At the micro-scale level, the grains interacts by enduring frictional contacts or by nearly instantaneous collisions. The first mechanism prevails at low shear rates, when the material behaves like a solid (quasi-static conditions); the latter prevails at high shear rates, when it behaves like a fluid or a granular gas (collisional conditions). This paper presents a new constitutive model able to describe the behaviour of granular materials from quasi-static to collisional conditions and the transition in between. The stress tensor is assumed to be the sum of a quasi-static and a collisional contribution: the former one is modelled by adopting an elasto-plastic model incorporating the critical state concept, whereas the latter stems from the kinetic theory of granular gases. The features of the constitutive model are illustrated with a volume element test; moreover the model has been implemented in the MPM code Anura3D and applied to the simulation of triaxial tests
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