220 research outputs found

    Experimental Investigation of Gully Formation Under Low Pressure and Low Temperature Conditions

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    International audienceIntroduction: A large morphological diversity of gullies is observed on Earth and on Mars. Debris flow – a non-newtonian flow comprising a sediment-water mix – is a common process attributed to gully formation on both planets [1, 2]. Many variables can influence the morphology of debris flows (grainsizes, discharge , slope, soil moisture, etc) and their respective influences are difficult to disentangle in the field. Furthermore effects specific to the martian environment have not yet been explored in detail. Some preliminary laboratory simulations have already been performed that isolate some of these variables. Cold room experiments [3] were already perfomed to test the effect of a melted surface layer on the formation of linear gullies over sand dunes. Low pressure experiments [4] were performed to test the effect of the atmospheric pressure on erosional capacity and runout distance of the flows. Our aim is to develop a new set of experiments both under Martian atmospheric pressure and terrestrial atmospheric pressure in order to reproduce the variability of the observed morphologies under well constrained experimental conditions

    Adaptive changes of human islets to an obesogenic environment in the mouse

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    Routing protocols in wireless sensor networks (WSN) face two main challenges: first, the challenging environments in which WSNs are deployed negatively affect the quality of the routing process. Therefore, routing protocols for WSNs should recognize and react to node failures and packet losses. Second, sensor nodes are battery-powered, which makes power a scarce resource. Routing protocols should optimize power consumption to prolong the lifetime of the WSN. In this paper, we present a new adaptive routing protocol for WSNs, we call it M^2RC. M^2RC has two phases: mesh establishment phase and data forwarding phase. In the first phase, M^2RC establishes the routing state to enable multipath data forwarding. In the second phase, M^2RC forwards data packets from the source to the sink. Targeting hop-by-hop reliability, an M^2RC forwarding node waits for an acknowledgement (ACK) that its packets were correctly received at the next neighbor. Based on this feedback, an M^2RC node applies multiplicative-increase/additive-decrease (MIAD) to control the number of neighbors targeted by its packet broadcast. We simulated M^2RC in the ns-2 simulator and compared it to GRAB, Max-power, and Min-power routing schemes. Our simulations show that M^2RC achieves the highest throughput with at least 10-30% less consumed power per delivered report in scenarios where a certain number of nodes unexpectedly fail.National Science Foundation (ITR ANI-0205294, EIA-0202067, ANI-0095988, ANI-9986397

    The use of pocket-size imaging devices: a position statement of the European Association of Echocardiography.

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    Pocket-size imaging devices are a completely new type of echo machines which have recently reached the market. They are very cheap, smartphone-size hand-held echo machines with limited technical capabilities. The aim of this European Association of Echocardiography (EAE) position paper is to provide recommendations on the use of pocket-size imaging devices in the clinical arena by profiling the educational needs of potential users other than cardiologists experts in echo. EAE recommendations about pocket-size imaging devices can be summarized in: (1) pocket-size imaging devices do not provide a complete diagnostic echocardiographic examination. The range of indications for their use is therefore limited. (2) Imaging assessment with pocket-size imaging devices should be reported as part of the physical examination of the patient. Image data should be stored according to the applicable national rules for technical examinations. (3) With the exception of cardiologists who are certified for transthoracic echocardiography according to national legislation, specific training and certification is recommended for all users. The certification should be limited to the clinical questions that can potentially be answered by pocket-size devices. (4) The patient has to be informed that an examination with the current generation of pocket-size imaging devices does not replace a complete echocardiogram.Peer reviewe

    Water and Sodium in Heart Failure: A Spotlight on Congestion.

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    Despite all available therapies, the rates of hospitalization and death from heart failure (HF) remain unacceptably high. The most common reasons for hospital admission are symptoms related to congestion. During hospitalization, most patients respond well to standard therapy and are discharged with significantly improved symptoms. Post-discharge, many patients receive diligent and frequent follow-up. However, rehospitalization rates remain high. One potential explanation is a persistent failure by clinicians to adequately manage congestion in the outpatient setting. The failure to successfully manage these patients post-discharge may represent an unmet need to improve the way congestion is both recognized and treated. A primary aim of future HF management may be to improve clinical surveillance to prevent and manage chronic fluid overload while simultaneously maximizing the use of evidence-based therapies with proven long-term benefit. Improvement in cardiac function is the ultimate goal and maintenance of a ‘‘dry’’ clinical profile is important to prevent hospital admission and improve prognosis. This paper focuses on methods for monitoring congestion, and strategies for water and sodium management in the context of the complex interplay between the cardiac and renal systems. A rationale for improving recognition and treatment of congestion is also proposed

    Right Heart Pulmonary Circulation Unit Response to Exercise in Patients with Controlled Systemic Arterial Hypertension: Insights from the RIGHT Heart International NETwork (RIGHT-NET)

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    Background. Systemic arterial hypertension (HTN) is the main risk factor for the development of heart failure with preserved ejection fraction (HFpEF). The aim of the study was was to assess the trends in PASP, E/E’ and TAPSE during exercise Doppler echocardiography (EDE) in hypertensive (HTN) patients vs. healthy subjects stratified by age. Methods. EDE was performed in 155 hypertensive patients and in 145 healthy subjects (mean age 62 ± 12.0 vs. 54 ± 14.9 years respectively, p < 0.0001). EDE was undertaken on a semi-recumbent cycle ergometer with load increasing by 25 watts every 2 min. Left ventricular (LV) and right ventricular (RV) dimensions, function and hemodynamics were evaluated. Results. Echo-Doppler parameters of LV and RV function were lower, both at rest and at peak exercise in hypertensives, while pulmonary hemodynamics were higher as compared to healthy subjects. The entire cohort was then divided into tertiles of age: at rest, no significant differences were recorded for each age group between hypertensives and normotensives except for E/E’ that was higher in hypertensives. At peak exercise, hypertensives had higher pulmonary artery systolic pressure (PASP) and E/E’ but lower tricuspid annular plane systolic excursion (TAPSE) as age increased, compared to normotensives. Differences in E/E’ and TAPSE between the 2 groups at peak exercise were explained by the interaction between HTN and age even after adjustment for baseline values (p < 0.001 for E/E’, p = 0.011 for TAPSE). At peak exercise, the oldest group of hypertensive patients had a mean E/E’ of 13.0, suggesting a significant increase in LV diastolic pressure combined with increased PASP. Conclusion. Age and HTN have a synergic negative effect on E/E’ and TAPSE at peak exercise in hypertensive subjects

    Linee guida di idrogeologia: approccio ai progetti

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    Da Cap. Introduzione: Lavorare in idrogeologia significa studiare il moto delle acque sotterranee, la geometria degli acquiferi, la dinamica dell’interazione fra acque sotterranee di differenti acquiferi e fra queste e le acque superficiali; non solo, significa anche comprendere come e perché opere antropiche, sia intenzionalmente che involontariamente, interagiscono con la risorsa acqua e conoscere metodologie e tecniche per progettare in modo ecosostenibile e nel rispetto della risorsa stessa. Nessun progetto di opera che interagisce, intenzionalmente o meno, poco o tanto, con le acque sotterranee può prescindere da un adeguato studio idrogeologico. I capitoli che seguono non pretendono il titolo di manuale, né aspirano a quello di “Bignami” di idrogeologia; le stesse parole “linee guida” presenti nel titolo, lungi dal presumere ogni valore normatorio, hanno solo carattere esplicativo, non una regola, ma piuttosto una traccia, anche perché la “dinamicità” con cui i quadri normativi comunitari, nazionali, regionali e locali si sono recentemente evoluti non permette di confrontarsi con un ambito di leggi e consuetudini collaudato e consolidato. Scopo esclusivo del documento è quello di fornire una guida ai colleghi, liberi professionisti o funzionari che siano, alle prese con la preparazione di studi, relazioni, istruttorie, controlli in materia di risorsa idrica. La prima parte dell’elaborato sintetizza i metodi e gli strumenti dell’idrogeologia (dal rilievo geologico alla geofisica, alla geochimica, ai metodi modellistici), puntualizzando i contenuti indispensabili e opzionali della relazione idrogeologica e della carta idrogeologica; la seconda parte tratta, più specificamente, di normativa e supporto idrogeologico per alcuni selezionati campi di attività (siti inquinati e discariche, viabilità ed infrastrutture lineari, ricerca idrica, pianificazione, attività estrattive). Il documento, privo di qualsiasi pretesa di esaustività sulle problematiche trattate, ha mirato comunque, approfittando della ricchezza di punti di vista derivante dalla vasta gamma di ruoli svolti nella professione dai colleghi della commissione, ad armonizzare le posizioni in un documento tecnico, forse dissonante nello stile, ma univoco negli scopi. Il capitolo 9 “Viabilità ed infrastrutture lineari” tratta del supporto idrogeologico per viabilità, in galleria o meno, di una certa rilevanza regionale; gli stessi approfondimenti, ovviamente tarati sull’importanza dell’opera, sono validi anche per le viabilità Provinciali e Comunali e per le minori. Un accenno a parte per il capitolo 10 “Ricerca idrica ed opere di approvvigionamento idrico” dove è stato ripreso in toto il documento della Commissione Pozzi del 2005, aggiornandolo ed aggiungendo un capitolo relativo alle sorgenti ed un capitolo su problematiche ambientali in cui fra l’altro si è affrontato il critico argomento, purtroppo in Italia ad oggi sottostimato (garbatissimo eufemismo), della definizione, mantenimento e ripristino della separazione fra falde idriche naturalmente distinte. Per quanto concerne le sorgenti, la trattazione tecnico-scientifica è stata privilegiata rispetto a quella burocratico-procedurale, soprattutto perché, nel 90% dei casi, l’iter burocratico per autorizzazioni e concessioni per le sorgenti è identico a quello per i pozzi, alla cui trattazione quindi si rimanda. Riguardo alla Pianificazione (capitolo 11), si è scelto di trattare a grandi linee solo la pianificazione a scala comunale nella Regione Toscana. Il settore pianificazione idrogeologica, che non poteva ovviamente essere omesso in un documento che tratta di idrogeologia, è un settore che in Italia è stato sviluppato, con un certo grado di approfondimento, solo in alcune regioni del nord, regioni che hanno dovuto affrontare gravi emergenze; per il resto, in genere, esso è sempre considerato, quando sia preso in considerazione, come appendice della pianificazione urbanistico-edilizia. La mancanza di norme specifiche in materia rende necessario un approccio di tipo scientifico-tecnico ed una trattazione ben più vasta ed articolata di quella necessaria per semplici linee guida quali sono, o per lo meno vorrebbero essere, quelle che seguono

    Stress echo 2020: The international stress echo study in ischemic and non-ischemic heart disease

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    Abstract Background Stress echocardiography (SE) has an established role in evidence-based guidelines, but recently its breadth and variety of applications have extended well beyond coronary artery disease (CAD). We lack a prospective research study of SE applications, in and beyond CAD, also considering a variety of signs in addition to regional wall motion abnormalities. Methods In a prospective, multicenter, international, observational study design, > 100 certified high-volume SE labs (initially from Italy, Brazil, Hungary, and Serbia) will be networked with an organized system of clinical, laboratory and imaging data collection at the time of physical or pharmacological SE, with structured follow-up information. The study is endorsed by the Italian Society of Cardiovascular Echography and organized in 10 subprojects focusing on: contractile reserve for prediction of cardiac resynchronization or medical therapy response; stress B-lines in heart failure; hypertrophic cardiomyopathy; heart failure with preserved ejection fraction; mitral regurgitation after either transcatheter or surgical aortic valve replacement; outdoor SE in extreme physiology; right ventricular contractile reserve in repaired Tetralogy of Fallot; suspected or initial pulmonary arterial hypertension; coronary flow velocity, left ventricular elastance reserve and B-lines in known or suspected CAD; identification of subclinical familial ..

    Competency-based cardiac imaging for patient-centred care. A statement of the European Society of Cardiology (ESC). With the contribution of the European Association of Cardiovascular Imaging (EACVI), and the support of the Association of Cardiovascular Nursing & Allied Professions (ACNAP), the Association for Acute CardioVascular Care (ACVC), the European Association of Preventive Cardiology (EAPC), the European Association of Percutaneous Cardiovascular Interventions (EAPCI), the European Heart Rhythm Association (EHRA), and the Heart Failure Association (HFA) of the ESC.

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    Imaging plays an integral role in all aspects of managing heart disease and cardiac imaging is a core competency of cardiologists. The adequate delivery of cardiac imaging services requires expertise in both imaging methodology-with specific adaptations to imaging of the heart-as well as intricate knowledge of heart disease. The European Society of Cardiology (ESC) and the European Association of Cardiovascular Imaging have developed and implemented a successful education and certification programme for all cardiac imaging modalities. This programme equips cardiologists to provide high quality competency-based cardiac imaging services ensuring they are adequately trained and competent in the entire process of cardiac imaging, from the clinical indication via selecting the best imaging test to answer the clinical question, to image acquisition, analysis, interpretation, storage, repository, and results dissemination. This statement emphasizes the need for competency-based cardiac imaging delivery which is key to optimal, effective and efficient, patient care

    Quality control of B-lines analysis in stress Echo 2020

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    Background The effectiveness trial “Stress echo (SE) 2020” evaluates novel applications of SE in and beyond coronary artery disease. The core protocol also includes 4-site simplified scan of B-lines by lung ultrasound, useful to assess pulmonary congestion. Purpose To provide web-based upstream quality control and harmonization of B-lines reading criteria. Methods 60 readers (all previously accredited for regional wall motion, 53 B-lines naive) from 52 centers of 16 countries of SE 2020 network read a set of 20 lung ultrasound video-clips selected by the Pisa lab serving as reference standard, after taking an obligatory web-based learning 2-h module ( http://se2020.altervista.org ). Each test clip was scored for B-lines from 0 (black lung, A-lines, no B-lines) to 10 (white lung, coalescing B-lines). The diagnostic gold standard was the concordant assessment of two experienced readers of the Pisa lab. The answer of the reader was considered correct if concordant with reference standard reading ±1 (for instance, reference standard reading of 5 B-lines; correct answer 4, 5, or 6). The a priori determined pass threshold was 18/20 (≥ 90%) with R value (intra-class correlation coefficient) between reference standard and recruiting center) > 0.90. Inter-observer agreement was assessed with intra-class correlation coefficient statistics. Results All 60 readers were successfully accredited: 26 (43%) on first, 24 (40%) on second, and 10 (17%) on third attempt. The average diagnostic accuracy of the 60 accredited readers was 95%, with R value of 0.95 compared to reference standard reading. The 53 B-lines naive scored similarly to the 7 B-lines expert on first attempt (90 versus 95%, p = NS). Compared to the step-1 of quality control for regional wall motion abnormalities, the mean reading time per attempt was shorter (17 ± 3 vs 29 ± 12 min, p < .01), the first attempt success rate was higher (43 vs 28%, p < 0.01), and the drop-out of readers smaller (0 vs 28%, p < .01). Conclusions Web-based learning is highly effective for teaching and harmonizing B-lines reading. Echocardiographers without previous experience with B-lines learn quickly.info:eu-repo/semantics/publishedVersio

    Randomized trial on the effects of a combined physical/cognitive training in aged MCI subjects: the Train the Brain study

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    Age-related cognitive impairment and dementia are an increasing societal burden. Epidemiological studies indicate that lifestyle factors, e.g. physical, cognitive and social activities, correlate with reduced dementia risk; moreover, positive effects on cognition of physical/cognitive training have been found in cognitively unimpaired elders. Less is known about effectiveness and action mechanisms of physical/cognitive training in elders already suffering from Mild Cognitive Impairment (MCI), a population at high risk for dementia. We assessed in 113 MCI subjects aged 65-89 years, the efficacy of combined physical-cognitive training on cognitive decline, Gray Matter (GM) volume loss and Cerebral Blood Flow (CBF) in hippocampus and parahippocampal areas, and on brain-blood-oxygenation-level-dependent (BOLD) activity elicited by a cognitive task, measured by ADAS-Cog scale, Magnetic Resonance Imaging (MRI), Arterial Spin Labeling (ASL) and fMRI, respectively, before and after 7 months of training vs. usual life. Cognitive status significantly decreased in MCI-no training and significantly increased in MCI-training subjects; training increased parahippocampal CBF, but no effect on GM volume loss was evident; BOLD activity increase, indicative of neural efficiency decline, was found only in MCI-no training subjects. These results show that a non pharmacological, multicomponent intervention improves cognitive status and indicators of brain health in MCI subjects
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