Studio sulle varietà a due dimensioni appartenenti a unS 4 euclideo

Sunto Si studiano le varietà a due dimensioni immerse in unS ₄ euclideo. Definite certe due normali principali, si esaminano le proprietà delle superficie nell'intorno di un punto, le curvature, e le sue linee più caratteristiche. Infine si dà sotto forma esplicita ed espressiva un gruppo di formule fondamentali relative all'impiego delle tre forme differenziali quadratiche atte a definire la varietà considerata.     

Bayesian Nonparametric Estimation for Reinforced Markov Renewal Processes

Starting from the definitions and the properties of reinforced renewal processes and reinforced Markov renewal processes, we characterize, via exchangeability and de Finetti’s representation theorem, a prior that consists of a family of Dirichlet distributions on the space of Markov transition matrices and beta-Stacy processes on distribution functions. Then, we show that this family is conjugate and give some estimate results.

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Surface chemical composition and fibrinogen adsorption-retention of fluoropolymer films deposited from an RF glow discharge

Fluoropolymer films have been deposited in the glow and afterglow regions of radio frequency glow discharges fed with C₂F₆−H₂ mixtures. Structure, growth rate, composition, and wettability of the films have been investigated by means of atomic force microscopy, electron spectroscopy for chemical analysis, secondary ion mass spectrometry, and water contact angle measurements.¹²⁵I labeled baboon fibrinogen in baboon plasma has been used to study the adsorption of the protein onto the films. Protein retention, i.e., the binding affinity of the adsorbed protein, has been examined by elution with a sodium dodecyl sulfate solution. Adsorption and retention of fibrinogen were correlated using multivariate statistical methods with the wettability, the degree of film fluorination, and the CF _x (1≤x≤3) group distribution of the coatings. This correlation identified the influence of each variable on the adsorption and retention of fibrinogen onto these substrates. These variables or surface properties can be easily balanced by properly tuning the experimental conditions of the glow discharge deposition process.