84 research outputs found
Alteration of volcanic deposits in the ANDRILL AND-1B core: Influence of paleodeposition, eruptive style, and magmatic composition
Alteration minerals, assemblages, and textures were studied in a 175-m-thick volcanic sequence found between 759.32 and 584.19 m below seafloor within the 1285-m-long ANDRILL (Antarctic Geological Drilling project) McMurdo Ice Shelf core (MIS AND-1B). Three main alteration zones were identified through the application of different analytical methods (optical and scanning electron microscopy, electron microprobe, and X-ray diffraction). Alteration zoning is guided by the texture of the volcanic deposits, which is in turn determined by the eruptive style, transport mechanisms, and paleodepositional conditions. In particular, alteration reflects the evolution of paleodepositional conditions from submarine or shallow water to subaerial due to the growth of a nearby volcanic edifice. The general alteration trend is also influenced by the contribution of volcanogenic sediments derived from the reworking of silica-rich pyroclasts from earlier volcanic activity
The relationship between volatile content and the eruptive style of basaltic magma: the Etna case
Fourier Transform Infrared (FT-IR) spectroscopic analyses of melt inclusions from four explosive eruptions of Etna (Italy) were conducted to determine pre-eruptive dissolved volatile concentrations. The studied eruptions include the 3930 BP subplinian, the 122 B.C. plinian, and the 4 January 1990 and the 23 December 1995 fountain fire eruptions. Preliminary results indicate that H2O varies between 3.13 and 1.02 wt% and CO2 between 1404 and 200 ppm. The most basic products (3930 BP tephra) contain the highest concentrations of CO2 (1404 ppm), whereas fire fountain hawaiitic tephra present the lowest values (< 200 ppm) indicating a continuous degassing process during the differentiation and rising of the magma. Generally, similar behavior has been found for water, characterized by a decreasing content during the differentiation that is mainly found in the 3930 BP eruption, 1990 and 1995 fire fountain products. Considering the relevance of volatile content and behaviour in determining the eruptive style, we made some inferences on the eruptive mechanisms based on the initial high volatile content and the degassing dynamics inside the plumbing system. These two factors suggest the cause of the high explosive activity in this basaltic volcano
From hot rocks to glowing avalanches: Numerical modelling of gravity-induced pyroclastic density currents and hazard maps at the Stromboli volcano (Italy)
Gravity-induced pyroclastic density currents (PDCs) can be produced by the collapse of volcanic crater rims or due to the gravitational instability of materials deposited in proximal areas during explosive activity. These types of PDCs, which are also known as âglowing avalanchesâ, have been directly observed, and their deposits have been widely identified on the flanks of several volcanoes that are fed by mafic to intermediatemagmas. In this research, the suitability of landslide numerical models for simulating gravity-induced PDCs to provide hazard assessmentswas tested. This work also presents the results of a back-analysis of three events that occurred in 1906, 1930 and 1944 at the Stromboli volcano by applying a depth-averaged 3Dnumerical code named DAN-3D. The model assumes a frictional internal rheology and a variable basal rheology (i.e., frictional, Voellmy and plastic). The numerical modelling was able to reproduce the gravity-induced PDCs' extension and deposit thicknesses to an order ofmagnitude of that reported
in the literature. The best resultswhen comparedwith field datawere obtained using a Voellmymodelwith a
frictional coefficient of f=0.19 and a turbulence parameter Ο=1000 m sâ1. The results highlight the suitability of this numerical code,which is generally used for landslides, to reproduce the destructive potential of these events in volcanic environments and to obtain information on hazards connected with explosive-related, mass-wasting phenomena in Stromboli Island and at volcanic systems characterized by similar phenomena.Published93-1065V. Dinamica dei processi eruttivi e post-eruttiviJCR Journa
Cardiovascular risk profile and lifestyle habits in a cohort of Italian cardiologists. Results of the SOCRATES survey
Objectives. To offer a snapshot of the personal health habits of Italian cardiologists, the Survey on Cardiac Risk Profile and Lifestyle Habits in a Cohort of Italian Cardiologists (SOCRATES) study was undertaken. Background. Cardiologists' cardiovascular profile and lifestyle habits are poorly known worldwide. Methods. A Web-based electronic self-reported survey, accessible through a dedicated website, was used for data entry, and data were transferred via the web to a central database. The survey was divided in 4 sections: baseline characteristics, medical illnesses and traditional cardiovascular risk factors, lifestyle habits and selected medication use. The e-mail databases of three national scientific societies were used to survey a large and representative sample of Italian cardiologists. Results. During the 3-month period of the survey, 1770 out of the 5240 cardiologists contacted (33.7%) completed and returned one or more sections of the questionnaire. More than 49% of the participants had 1 out of 5 classical risk factors (e.g. hypertension, hypercholesterolemia, active smoking, diabetes and previous vascular events). More than 28% of respondents had 2 to 5 risk factors and only 22.1% had none and therefore, according to age and sex, could be considered at low-intermediate risk. Despite the reported risk factors, more than 90% of cardiologists had a self-reported risk perception quantified as mild, such as low or intermediate. Furthermore, overweight/obesity, physical inactivity and stress at work or at home were commonly reported, as well as a limited use of cardiovascular drugs, such as statins or aspirin. Conclusions. The average cardiovascular profile of Italian cardiologist is unlikely to be considered ideal or even favorable according to recent statements and guidelines regarding cardiovascular risk. Thus, there is a large room for improvement and a need for education and intervention
From risk charts to guidelines: tools for evaluation and management of cardiovascular risk
Despite the wide improvement of diagnostic techniques and the introduction of effective pharmacological and instrumental therapeutic strategies aimed to the treatment of cardiovascular diseases, their incidence and lethality are still elevated, with economic implications increasingly less sustainable by the public medical systems. The modern practice of cardiovascular prevention requires, thus, that diagnostic and therapeutic interventions, both at population level and on the single patient, should be more and more precise, effective, and appropriate. From this point of view, a correct global cardiovascular risk stratification assumes a preponderant relevance, in order to allow an adequate therapeutical response. For this purpose several work instruments, as risk charts and guidelines, namely dedicated to arterial hypertension and dyslipidemias, were developed and offered to clinicians interested in cardiovascular prevention. The aim of this review is to illustrate, in synthesis, those instruments, aiming to facilitate their implementation, thus reducing the actual gap between theoretical indications and the real world
Awareness and appropriateness of the management of preclinical heart failure in outpatient clinics in Italy: Insights from the VASTISSIMO study - EValuation of the AppropriateneSs of The preclInical phase (Stage A and Stage B) of Heart FaIlure Management in Outpatient Clinics in Italy
A key factor in cardiovascular prevention is the detection and appropriate management of preclinical heart failure (HF), but information on the subject is scarce. We designed VASTISSIMO as a prospective, observational study to investigate Outpatient Clinic Cardiologistsâ skills in detecting and managing preclinical HF in Italy. Quality scores were used to assess the appropriateness of clinical management according to guideline recommendations. The feasibility of making a diagnosis of preclinical HF in a cardiology outpatient clinical setting, cardiologistsâ awareness of preclinical HF and consistency between physicianâs perceived risk of HF and the patientâs classiïŹcation into the preclinical HF Stages A [(SAHF) or B (SBHF)] have been investigated. Consistency was defined acceptable if the concordance between perceived risk and actual risk was >70%. Out of 3322 patients included in the study data necessary for identifying SBHF were collected in 2106 (63.4%). Many SBHF patients had their risk underestimated: 16.2% of those with previous acute myocardial infarction (AMI), 23.1% with left ventricular hypertrophy (LVH) at ECG/echocardiography, 30% with systolic/diastolic dysfunction, and 14.3% with valve disease. Cardiologistsâ awareness of preclinical HF in the outpatient setting should be improved. This is a critical area of cardiovascular prevention that requires attention to improve good clinical practice and adherence to guidelines
After ACC/AHA and ESC Guidelines Pre-operative cardiological evaluation in non-cardiac surgery: certainties, controversial areas and opportunities for a team approach
A standardized and evidence-based approach to the cardiological management of patients undergoing noncardiac surgery has been recently defined by Task Forces of the American Heart Association (AHA), American College of Cardiology (ACC) and the European Society of Cardiology (ESC) that published their guidelines in 2007 and 2009, respectively. Both the recommendations moved from risk indices to a practical, stepwise approach of the patient, which integrates clinical risk factors and test results with the estimated stress of the planned surgical procedure. In the present paper the main topics of the guidelines are discussed, and moreover, emphasis is placed on four controversial issues such as the use of prophylactic coronary revascularization in patients with myocardial ischemia, the perioperative management of patients with congestive heart failure, the routine use of betablockers and statins, and, finally, the management of antiplatelet therapies in patients with coronary stents. In addition to promoting an improvement of immediate perioperative care, the preoperative cardiological evaluation should be a challenge for identifying subjects with enhanced risk of cardiovascular events, who should be treated and monitored during a long-term follow-up
Ischemic wound revascularization by the stromal vascular fraction relies on host-donor hybrid vessels
Nonhealing wounds place a significant burden on both quality of life of affected patients and health systems. Skin substitutes are applied to promote the closure of nonhealing wounds, although their efficacy is limited by inadequate vascularization. The stromal vascular fraction (SVF) from the adipose tissue is a promising therapy to overcome this limitation. Despite a few successful clinical trials, its incorporation in the clinical routine has been hampered by their inconsistent results. All these studies concluded by warranting pre-clinical work aimed at both characterizing the cell types composing the SVF and shedding light on their mechanism of action. Here, we established a model of nonhealing wound, in which we applied the SVF in combination with a clinical-grade skin substitute. We purified the SVF cells from transgenic animals to trace their fate after transplantation and observed that it gave rise to a mature vascular network composed of arteries, capillaries, veins, as well as lymphatics, structurally and functionally connected with the host circulation. Then we moved to a human-in-mouse model and confirmed that SVF-derived endothelial cells formed hybrid human-mouse vessels, that were stabilized by perivascular cells. Mechanistically, SVF-derived endothelial cells engrafted and expanded, directly contributing to the formation of new vessels, while a population of fibro-adipogenic progenitors stimulated the expansion of the host vasculature in a paracrine manner. These data have important clinical implications, as they provide a steppingstone toward the reproducible and effective adoption of the SVF as a standard care for nonhealing wounds
Cardiac Prevention and Rehabilitation â3.0â: From acute to chronic phase. Position Paper of the ltalian Association for Cardiovascular Prevention and Rehabilitation (GICR-IACPR)
Cardiac rehabilitation (CR) is the subspecialty of clinical cardiology dedicated to the treatment of cardiac patients, early and in the long term after an acute event. The aim of CR is to improve both quality of life and prognosis through prognostic stratification, clinical stabilization and optimization of therapy (pharmacological and non), management of comorbidities, treatment of disability, as well as through the provision and reinforcement of secondary prevention interventions and maintenaince of adherence to treatment.
The mission of CR has changed over time. Once centered on the acute phase, aimed primarily at short-term survival, the healthcare of cardiac patients now increasingly involves the chronic phase where the challenge is to guarantee continuity and quality of care in the medium and long-term. The aim of the present position paper is to provide the state-of-the-art of CR in Italy, discussing its trengths and weaknesses as well as future perspectives
Holocene eruptive history of the Stromboli volcano: Constraints from paleomagnetic dating
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