760 research outputs found
The extensive age gradient of the Carina dwarf galaxy
The evolution of small systems such as dwarf spheroidal galaxies (dSph) is
likely to have been a balance between external environmental effects and
internal processes within their own relatively shallow potential wells.
Assessing how strong such environmental interactions may have been is therefore
an important element in understanding the baryonic evolution of dSphs and their
derived dark matter distribution.
Here we present results from a wide-area CTIO/MOSAIC II photometric survey of
the Carina dSph, reaching down to about two magnitudes below the oldest main
sequence turn-off (MSTO). This data-set enables us to trace the structure of
Carina in detail out to very large distances from its center, and as a function
of stellar age.
We observe the presence of an extended structure made up primarily of ancient
MSTO stars, at distances between 25arcmin-60arcmin from Carina's center,
confirming results in the literature that Carina extends well beyond its
nominal tidal radius.
The large number statistics of our survey reveals features such as isophote
twists and tails that had gone undetected in other previous shallower surveys.
This is the first time that such unambiguous signs of tidal disruption have
been found in a Milky Way "classical" dwarf other than Sagittarius.
We also demonstrate the presence of a negative age gradient in Carina
directly from its MSTOs, and trace it out to very large distances from the
galaxy center. The signs of interaction with the Milky Way make it unclear
whether the age gradient was already in place before Carina underwent tidal
disruption.Comment: Accepted for publication in The Astrophysical Journal Letter
Simulation of free-surface flows by a finite element interface capturing technique
Transient free-surface (FS) flows are numerically simulated by a finite element interface capturing method based on a level set approach. The methodology consists of the solution of two-fluid viscous incompressible flows for a single domain, where the liquid phase is identified by the positive values of the level set function, the gaseous phase by negative ones, and the FS by the zero level set. The numerical solution at each time step is performed in three stages: (i) a two-fluid Navier-Stokes stage, (ii) an advection stage for the transport of the level set function and (iii) a bounded reinitialisation with continuous penalisation stage for keeping smoothness of the level set function. The proposed procedure, and particularly the renormalisation stage, is evaluated in three typical two- and threedimensional problems.Fil: Battaglia, Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Storti, Mario Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: D'elia, Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentin
Nonprofit foundations spur translational research
Every year, hundreds of promising basic discoveries in the pharmacological field are lost and will never have a chance to be exploited for patients due to difficulties in clinical translation. This is especially true for most neurodegenerative disorders lacking disease-modifying therapies. Here we present the current scenario and our vision of a 'collective-impact' multistakeholder approach to expedite the development of new drugs
Asthma in the elderly: A different disease?
Asthma is a chronic airway disease that affects all ages, but does this definition also include the elderly? Traditionally, asthma has been considered a disease of younger age, but epidemiological studies and clinical experience support the concept that asthma is as prevalent in older age as it is in the young. With the ever-increasing elderly population worldwide, the detection and proper management of the disease in old age may have a great impact from the public health perspective. Whether asthma in the elderly maintains the same characteristics as in young populations is an interesting matter. The diagnostic process in older individuals with suspected asthma follows the same steps, namely a detailed history supported by clinical examination and laboratory investigations; however, it should be recognised that elderly patients may partially lose reversibility of airway obstruction. The correct interpretation of spirometric curves in the elderly should take into account the physiological changes in the respiratory system. Several factors contribute to delaying the diagnosis of asthma in the elderly, including the age-related impairment in perception of breathlessness. The management of asthma in advanced age is complicated by the comorbidities and polypharmacotherapy, which advocate for a comprehensive approach with a multidimensional assessment. It should be emphasised that older age frequently represents an exclusion criterion for eligibility in clinical trials, and current asthma medications have rarely been tested in elderly asthmatics. Ageing is associated with pharmacokinetic changes of the medications. As a consequence, absorption, distribution, metabolism and excretion of antiasthmatic medications can be variably affected. Similarly, drug-to-drug interactions may reduce the effectiveness of inhaled medications and increase the risk of side-effects. For this reason, we propose the term “geriatric asthma” be preferred to the more generic “asthma in the elderly”
La colecistectomia videolaparoscopica elettiva: i limiti di un sogno ormai realtà
La tecnica laparoscopica per la colecistectomia elettiva è il capolinea di un’evoluzione volta a ridurre ai minimi termini la via d’accesso.
Abbiamo analizzato dal 1° gennaio 2004 al 31 dicembre 2006 un totale di 5515 interventi di colecistectomia, di cui 4877 laparoscopici e 635 in tecnica tradizionale. Le complicanze e le diagnosi aggiuntive sono state codificate ricercandole nel database delle SDO della Regione Lombardia. La morbilità è stata di 82 casi (12.9%) con la tecnica tradizionale e da 109 casi (2.23%) con la tecnica laparoscopica; la mortalità è stata di 11 casi (1.73%) con la tecnica tradizionale e di 1 caso (0.02%) con la tecnica laparoscopia. Le giornate di degenza media sono state 14.40 con la tecnica tradizionale e 4.75 con la tecnica laparoscopia
La morbilità nella tecnica open è sei volte superiore rispetto alla tecnica laparoscopica. Questo divario tra le due tecniche è presente in tutte le casistiche mondiali ed è il risultato della mini-invasività della laparoscopia rispetto all’incisione laparotomica, condizione che spiega e giustifica anche la differenza per quanto riguarda i giorni di degenza media in favore ovviamente della tecnica laparoscopia. La mortalità così alta nella tecnica tradizionale rispetto alla laparoscopia è da attribuirsi ai casi selezionati
La prima importante osservazione è che nei nostri ospedali, come in tutti i migliori del mondo, la colecistectomia laparoscopica è diventata il gold standard di trattamento della colelitiasi e la seconda è che sempre di più la tecnica open è riservata alla patologia complicata della litiasi della colecisti e questo quindi ne giustifica l’importante divario, rispetto alla tecnica laparoscopica, per quanto concerne le giornate di degenza, la morbilità e la mortalità
Steps towards collective sustainability in biomedical research
The optimism surrounding multistakeholder research initiatives does not match the clear view of policies that are needed to exploit the potential of these collaborations. Here we propose some action items that stem from the integration between research advancements with the perspectives of patient-advocacy organizations, academia, and industry
Prevalenza della sclerosi multipla nell'isola d'Elba
Introduzione Le variazioni temporali e geografiche della frequenza di Sclerosi Multipla (SM) sono state molto studiate. Negli ultimi 30 anni, gli studi epidemiologici hanno evidenziato come la distribuzione della malattia nei paesi dell’area mediterranea, anche in Italia, sia più complessa di quanto ritenuto in passato quando era comunemente accettato il modello correlato alla latitudine (1, 2). Scarsi sono i dati di prevalenza relativi all’Italia centrale e in particolare ad oggi non sono noti dati pubblicati sulla dimensione di questa patologia nella popolazione dell’isola d’Elba.
Obiettivi Calcolare la prevalenza della SM nell’isola d’Elba dal momento che non ci sono dati disponibili in letteratura.
Metodi L'isola d'Elba è l’isola più grande dell'Arcipelago Toscano e la terza più grande d'Italia dopo la Sicilia e la Sardegna (223 km²). Al giorno di prevalenza, ovvero il 31/12/2010, la popolazione residente nell’isola era pari a 31.943 abitanti.
I casi di SM sono stati identificati consultando le cartelle cliniche dell’ospedale e dell’ambulatorio di riferimento neurologico dell’isola. Sono stati arruolati nello studio tutti i pazienti con diagnosi di SM secondo i criteri di McDonald, residenti nell’isola al giorno di prevalenza.
Sono stati calcolati i tassi di prevalenza grezzi e specifici (sesso e età) e il tasso standardizzato rispetto alla popolazione italiana del 2001. Gli intervalli di confidenza al 95% dei tassi di prevalenza sono stati calcolati assumendo una distribuzione di Poisson.
Risultati Al giorno di prevalenza erano residenti nell’isola 42 soggetti con SM. Di questi il 59,5% era nato ed era tutt’ora residente nell’isola, mentre il 40,5% era nato fuori dall’isola. Tra i 42 soggetti con SM, 4 avevano origine sarda.
Il rapporto F:M è risultato pari a 2,8: infatti il 73,8% era di sesso femminile rispetto al 26,2% di sesso maschile. L’età media dei soggetti era di 49,8±12,6 anni e non si osservano differenze significative tra i sessi riguardo all’età (M: 52,9±10,7, F: 48,7±12,6; p = 0,329).
Per quanto riguarda le forme di malattia, il 16,7% dei pazienti aveva una forma CIS, il 61,9% una RR, il 16,7% una SP e il 4,8% una PP. Il grado di disabilità (EDSS) è risultato correlato (trend crescente) con la forma di malattia: EDSS pari a 1,5 per le forme CIS, 2,0 per le forme RR e 6,0 per le forme SP e PP. La durata di malattia, in media, era di 15,0±9,8 anni, con un range tra 0 e 37 anni. La durata media di malattia è risultata più alta per i maschi (19,3±9,5 anni) rispetto alle femmine (13,6±9,6 anni) ma tale differenza non è statisticamente rilevante (p = 0,109).
Il tasso di prevalenza grezzo è risultato pari a 131,5 (IC 95%: 99,8-177,7) per 100.000 (maschi 70,7; femmine 189,2 per 100.000). Il tasso di prevalenza standardizzato è risultato pari a 131,5 (IC 95%: 91,8-171,2) per 100.000.
Il tasso di prevalenza sesso età specifico mostra un picco, per entrambi i sessi, nella classe di età tra 45-54 anni, mentre non ci sono casi prima dei 15 anni
Home respiratory muscle training in patients with chronic obstructive pulmonary disease
The benefits of inspiratory muscle strength training in decreasing symptoms, disability or handicap of patients affected by COPD are not well established. The objective of this study was to assess the efficacy of the constant use of a new flow-volumetric inspiratory exerciser, named Respivol™, in improving respiratory functional parameters in COPD patients. Twenty consecutive ambulatory patients affected by COPD were enrolled. Each patient was assessed, before and after 3 and 6 months inspiratory exercise with Respivol™, for the following clinical parameters: maximal inspiratory pressure, maximal expiratory pressure, dyspnoea grade, quality of life by a self-administered St George questionnaire and a 6-min walking test. After a brief progressive ambulatory training programme, inspiratory exercise with Respivol™ was performed at home for 6 months. All patients used Respivol™ together with medical treatment. Maximal inspiratory pressure and maximal expiratory pressure values were significantly increased after 3 and 6 months of exercise. Dyspnoea grade was significantly reduced and the 6-min walking test showed an increase in effort tolerance, after 6 months of home training. Quality of life assessment showed an improvement, associated with a decrease of respiratory disease symptoms. Inspiratory muscle strength training with Respivol™ seems to be efficient in reducing symptoms and improving quality of life in adults with COPD
Presenting evidence-based health information for people with multiple sclerosis : the IN-DEEP project protocol
Background - Increasingly, evidence-based health information, in particular evidence from systematic reviews, is being made available to lay audiences, in addition to health professionals. Research efforts have focused on different formats for the lay presentation of health information. However, there is a paucity of data on how patients integrate evidence-based health information with other factors such as their preferences for information and experiences with information-seeking. The aim of this project is to explore how people with multiple sclerosis (MS) integrate health information with their needs, experiences, preferences and values and how these factors can be incorporated into an online resource of evidence-based health information provision for people with MS and their families.Methods - This project is an Australian-Italian collaboration between researchers, MS societies and people with MS. Using a four-stage mixed methods design, a model will be developed for presenting evidence-based health information on the Internet for people with MS and their families. This evidence-based health information will draw upon systematic reviews of MS interventions from The Cochrane Library. Each stage of the project will build on the last. After conducting focus groups with people with MS and their family members (Stage 1), we will develop a model for summarising and presenting Cochrane MS reviews that is integrated with supporting information to aid understanding and decision making. This will be reviewed and finalised with people with MS, family members, health professionals and MS Society staff (Stage 2), before being uploaded to the Internet and evaluated (Stages 3 and 4).Discussion - This project aims to produce accessible and meaningful evidence-based health information about MS for use in the varied decision making and management situations people encounter in everyday life. It is expected that the findings will be relevant to broader efforts to provide evidence-based health information for patients and the general public. The international collaboration also permits exploration of cultural differences that could inform international practice.<br /
Cross-validation of active and passive microwave snowfall products over the continental United States
Surface snowfall rate estimates from the Global Precipitation Measurement (GPM) mission’sCoreObservatorysensors and theCloudSatradar are compared to those from the Multi-Radar Multi-Sensor (MRMS) radarcomposite product over the continental United States during the period from November 2014 to September 2020. Theanalysis includes the Dual-Frequency Precipitation Radar (DPR) retrieval and its single-frequency counterparts, the GPMCombined Radar Radiometer Algorithm (CORRA), theCloudSatSnow Profile product (2C-SNOW-PROFILE), and twopassive microwave retrievals, i.e., the Goddard Profiling algorithm (GPROF) and the Snow Retrieval Algorithm for GMI(SLALOM). The 2C-SNOW retrieval has the highest Heidke skill score (HSS) for detecting snowfall among the productsanalyzed. SLALOM ranks second; it outperforms GPROF and the other GPM algorithms, all detecting only 30% of thesnow events. Since SLALOM is trained with 2C-SNOW, it suggests that the optimal use of the information content in theGMI observations critically depends on the precipitation training dataset. All the retrievals underestimate snowfall ratesby a factor of 2 compared to MRMS. Large discrepancies (RMSE of 0.7–1.5 mm h21) between spaceborne and ground-based snowfall rate estimates are attributed to the complexity of the ice scattering properties and to the limitations of theremote sensing systems: the DPR instrument has low sensitivity, while the radiometric measurements are affected by theconfounding effects of the background surface emissivity and of the emission of supercooled liquid droplet layers
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