1,174 research outputs found

    PSI-based methodology to land subsidence mechanism recognition

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    Abstract. A methodology based on Persistent Scatterer Interferometry (PSI) is proposed in order to disentangle the contribution of different processes that act at different spatio-temporal scales in land subsidence (i.e. vadose zone processes as swelling/shrinkage of clay soils, soil consolidation and fluid extraction). The methodology was applied in different Italian geological contexts characterized by natural and anthropic processes (i.e. a Prealpine valley and the Po Plain in northern Italy)

    Using the Sound Card as a Timer

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    Experiments in mechanics can often be timed by the sounds they produce. In such cases, digital audio recordings provide a simple way of measuring time intervals with an accuracy comparable to that of photogate timers. We illustrate this with an experiment in the physics of sports: to measure the speed of a hard-kicked soccer ball.Comment: 3 pages, 4 figures, Late

    High Energy Break and Reflection Features in the Seyfert Galaxy MCG+8-11-11

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    We present the results from ASCA and OSSE simultaneous observations of the Seyfert 1.5 galaxy MCG+8-11-11 performed in August-September 1995. The ASCA observations indicate a modest flux increase (20%) in 3 days, possibly correlated to a softening of the 0.6-9 keV spectrum. The spectrum is well described by a hard power law (Gamma=1.64) absorbed by a column density slightly larger than the Galactic value, with an iron line at 6.4 keV of EW=400 eV. The simultaneous OSSE data are characterized by a much softer power law with photon index Gamma=3.0, strongly suggesting the presence of a spectral break in the hard X/soft gamma-ray band. A joint fit to OSSE and ASCA data clearly shows an exponential cut-off at about 300 keV, and strong reflection component. MCG+8-11-11 features a spectral break in the underlying continuum unambiguously. This, together with the inferred low compactness of this source, favours thermal or quasi-thermal electron Comptonization in a structured Corona as the leading process of high energy radiation production.Comment: 13 pages, + 4 figure.ps AAS LateX [11pt,aasms4]{article} To be published in ApJ, Main Journa

    Regular vs. classical M\"obius transformations of the quaternionic unit ball

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    The regular fractional transformations of the extended quaternionic space have been recently introduced as variants of the classical linear fractional transformations. These variants have the advantage of being included in the class of slice regular functions, introduced by Gentili and Struppa in 2006, so that they can be studied with the useful tools available in this theory. We first consider their general properties, then focus on the regular M\"obius transformations of the quaternionic unit ball B, comparing the latter with their classical analogs. In particular we study the relation between the regular M\"obius transformations and the Poincar\'e metric of B, which is preserved by the classical M\"obius transformations. Furthermore, we announce a result that is a quaternionic analog of the Schwarz-Pick lemma.Comment: 14 page

    Flotation Sludges from Precious Metal Recovery Processes: From Waste to Secondary Raw Material in Ceramics

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    In this study, we investigated flotation muds (FM) deriving from the recovery processes of precious metals contained in e-waste (wastes from electronics) and exhausted catalysts. FM consist of an amorphous phase, corresponding to a Ca- and Al-rich silicatic glass, potentially usable as a secondary raw material (SRM) to obtain a final ceramic product (CFM). A high FM amount was used in our ceramic tests, and suitably mixed with variable percentages of other phases. Chemical analysis, phase composition, microstructure, pore pattern and technological properties of the new ceramic products were determined using different analytical techniques, including bulk XRF, XRD, SEM-EDS and µCT. The CFM product predominantly consists of nepheline, pyroxene and wollastonite as the main crystalline phases, with a minor amorphous phase occurring as a compact interstitial matrix. The ceramic product has a porous interconnected microstructure. Nevertheless, this microstructure does not negatively affect the mechanical properties of the ceramic product, as testified by the geo-mechanical tests, revealing good properties in terms of bending and uniaxial strength. These preliminary results point out that FM recycling is feasible, at least at the laboratory scale

    Detección de adulteraciones en grasa láctea a través del tratamiento por regresión lineal múltiple de perfiles de ácidos grasos totales

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    The total fatty acids profile of a genuine milk fat from an important milk producing area of Argentina was determined together with the total fatty acids profiles of sunflower, soybean and coconut oils and bovine and porcine fats. These results were used for characterization of the fatty acid profile of genuine milk fat and for detection of the adulteration of milk fat with those oils and fats. Triglycerides were transesterified in an acid medium with ethanol – sulfuric acid. Ethyl esters were quantified by gas chromatography using two internal standards (C7:0 and C17:0 ) added to the anhydrous fat. The most characteristic fatty acids were determined. The fatty acids profiles of mixtures of milk fat with vegetable and animal fats were mathematically calculated. Vegetable oils were added from 2 to 10 %, while animal fats were added up to 15 %. In this way different data matrices were obtained. Stepwise multiple regression analysis was applied to these matrices with the aim of obtaining a relation between adulteration percentage and the total fatty acids profile for each fat selected as adulterant. Good correlation coefficients were obtained for analyzed matrices. Equations were validated by employing the cross validation method, and were applied to genuine samples of milk fat and to mixtures by mass balances of these milk fats with the different adulterant fats. A good prediction of adulterations was obtained with the application of equations.Se determinó el perfil de ácidos grasos totales de muestras de grasa láctea genuina de una importante cuenca lechera de la República Argentina obtenidas durante un año (2002-2003), y de aceites de girasol, soja, coco y sebos vacuno y porcino, con el objetivo de estudiar el perfil característico de la grasa láctea y poder detectar adulteraciones de la misma con las grasas mencionadas. Se empleó el método de transesterificación de los triglicéridos en medio ácido, utilizando etanol-ácido sulfúrico, y se cuantificaron los ésteres etílicos por cromatografía de gases empleando dos estándares internos que se adicionaron a la grasa anhidra (C7:0 y C17:0 ). Se cuantificaron los ácidos grasos más característicos de las grasas estudiadas . Se obtuvieron matemáticamente los perfiles de mezclas de las grasas lácteas con las distintas materias grasas mencionadas, cubriendo un rango del 2 al 10 % de adición (porcentaje de adulteración) para los aceites y grasas vegetales y hasta el 15 % para las grasas de origen animal. De esta manera se obtuvieron diferentes matrices de datos a las que se les aplicó el método de regresión lineal múltiple con selección por stepwise con el propósito de obtener una función que relacionara el porcentaje de adulteración con los perfiles de ácidos grasos totales para cada materia grasa ensayada como adulterante. Se obtuvieron buenos coeficientes de correlación para las matrices de datos analizadas. Las ecuaciones se validaron con el empleo del método de validación interna o cruzada, con muestras genuinas de grasa láctea y con mezclas preparadas por balances de masa de dichas grasas lácteas con las distintas materias grasas adulterantes. Las ecuaciones obtenidas mostraron un buen ajuste para la predicción de las adulteraciones estudiadas

    Focus on the use of resveratrol in bladder cancer

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    Bladder cancer is the most common tumor of the urinary system, with a high incidence in the male population. Surgery and intravesical instillations can eradicate it, although recurrences are very common, with possible progression. For this reason, adjuvant therapy should be considered in all patients. Resveratrol displays a biphasic dose response both in vitro and in vivo (intravesical application) with an antiproliferative effect at high concentrations and antiangiogenic action in vivo (intraperitoneal application) at a low concentration, suggesting a potential role for it in clinical management as an adjuvant to conventional therapy. In this review, we examine the standard therapeutical approach to bladder cancer and the preclinical studies that have investigated resveratrol in xenotransplantation models of bladder cancer. Molecular signals are also discussed, with a particular focus on the STAT3 pathway and angiogenic growth factor modulation

    Role of computed tomography in predicting critical disease in patients with covid-19 pneumonia: a retrospective study using a semiautomatic quantitative method

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    Background: So far, only a few studies evaluated the correlation between CT features and clinical outcome in patients with COVID-19 pneumonia. Purpose: To evaluate CT ability in differentiating critically ill patients requiring invasive ventilation from patients with less severe disease. Methods: We retrospectively collected data from patients admitted to our institution for COVID-19 pneumonia between March 5th-24th. Patients were considered critically ill or non-critically ill, depending on the need for mechanical ventilation. CT images from both groups were analyzed for the assessment of qualitative features and disease extension, using a quantitative semiautomatic method. We evaluated the differences between the two groups for clinical, laboratory and CT data. Analyses were conducted on a per-protocol basis. Results: 189 patients were analyzed. PaO2/FIO2 ratio and oxygen saturation (SaO2) were decreased in critically ill patients. At CT, mixed pattern (ground glass opacities (GGO) and consolidation) and GGO alone were more frequent respectively in critically ill and in non-critically ill patients (p < 0.05). Lung volume involvement was significantly higher in critically ill patients (38.5 % vs. 5.8 %, p < 0.05). A cut-off of 23.0 % of lung involvement showed 96 % sensitivity and 96 % specificity in distinguishing critically ill patients from patients with less severe disease. The fraction of involved lung was related to lactate dehydrogenase (LDH) levels, PaO2/FIO2 ratio and SaO2 (p < 0.05). Conclusion: Lung disease extension, assessed using quantitative CT, has a significant relationship with clinical severity and may predict the need for invasive ventilation in patients with COVID-19
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