1,349 research outputs found
I traccianti nelle ricerche sul Timavo
The aim of this work is the collection in an organic ensemble of the data scattered throughout a vast bibliography, on the basis of which the characteristics of Timavo’s underground hydrography are outlined.
The study of connections between inputs and outflows and the hydrochemical and isotopic analysis have characterized and differentiated the different water bodies that contribute to feed the headwater region of the “Classical Karst”, a natural laboratory for excellence of these studies, from which they have indeed taken the name of the Karst, the Karst phenomena in general and in particular the same Karst hydrology.
How many will want to continue on this way, will find in this overview the most significant numerical data collected in different surveys, linked by the thread of the interpretations developed by the authors of the researches; my remarks are given between brackets in the text or in footnotes.Lo scopo di questo lavoro è la raccolta in un insieme organico dei dati sparsi in una vasta bibliografia, sulla base dei quali sono descritte le caratteristiche dell'idrografia sotterranea di Timavo. Lo studio delle connessioni tra gli ingressi e i deflussi e l'analisi idrochimica e isotopica ha caratterizzato e differenziato i diversi corpi idrici che contribuiscono a nutrire la regione delle acque glauche del "Carso classico", un laboratorio naturale per eccellenza di questi studi, da cui hanno infatti preso il nome di Carso i fenomeni carsici in generale e in particolare la stessa idrologia carsica. Quanti vogliono continuare in questo modo, troveranno in questa panoramica i dati numerici più significativi raccolti in diverse indagini, legati dal filo delle interpretazioni sviluppate dagli autori delle ricerche; le mie osservazioni sono date tra parentesi nel testo o nelle note a piè di pagina
On the relative abundance of LiH and LiH+ molecules in the early universe: new results from quantum reactions
The relative efficiencies of the chemical pathways that can lead to the
destruction of LiH and LiH+ molecules, conjectured to be present in the
primordial gas and to control molecular cooling processes in the gravitational
collapse of the post-recombination era, are revisited by using accurate quantum
calculations for the several reactions involved. The new rates are employed to
survey the behavior of the relative abundance of these molecules at redshifts
of interest for early universe conditions. We find significant differences with
respect to previous calculations, the present ones yielding LIH abundances
higher than LiH+ at all redshifts.Comment: The Astrophysical Journal, in pres
A demonstrator for bolometric interferometry
Bolometric Interferometry (BI) is one of the most promising techniques for
precise measurements of the Cosmic Microwave Background polarization. In this
paper, we present the results of DIBO (Demonstrateur d'Interferometrie
Bolometrique), a single-baseline demonstrator operating at 90 GHz, built to
proof the validity of the BI concept applied to a millimeter-wave
interferometer. This instrument has been characterized in the laboratory with a
detector at room temperature and with a 4 K bolometer. This allowed us to
measure interference patterns in a clean way, both (1) rotating the source and
(2) varying with time the phase shift among the two interferometer's arms.
Detailed modelisation has also been performed and validated with measurements.Comment: 15 pages, 14 figure
A Pipelined Tracer-Aware Approach for Lesion Segmentation in Breast DCE-MRI
The recent spread of Deep Learning (DL) in medical imaging is pushing researchers to explore its suitability for lesion segmentation in Dynamic Contrast-Enhanced Magnetic-Resonance Imaging (DCE-MRI), a complementary imaging procedure increasingly used in breast-cancer analysis. Despite some promising proposed solutions, we argue that a “naive” use of DL may have limited effectiveness as the presence of a contrast agent results in the acquisition of multimodal 4D images requiring thorough processing before training a DL model. We thus propose a pipelined approach where each stage is intended to deal with or to leverage a peculiar characteristic of breast DCE-MRI data: the use of a breast-masking pre-processing to remove non-breast tissues; the use of Three-Time-Points (3TP) slices to effectively highlight contrast agent time course; the application of a motion-correction technique to deal with patient involuntary movements; the leverage of a modified U-Net architecture tailored on the problem; and the introduction of a new “Eras/Epochs” training strategy to handle the unbalanced dataset while performing a strong data augmentation. We compared our pipelined solution against some literature works. The results show that our approach outperforms the competitors by a large margin (+9.13% over our previous solution) while also showing a higher generalization ability
Vibrational level population of H and H in the early Universe
We formulate a vibrationally resolved kinetics for molecular hydrogen and its
cation in the primordial Universe chemistry. Formation, destruction and
relaxation processes for each vibrational level are studied and included as
chemical pathways of the present model. The fractional abundance of each
vibrational level as a function of the redshift is given: a strong deviation
from the Boltzmann distribution is found at low . A discussion of the
results is provided, also evaluating the effects of relaxation processes on the
level populations. Analytical fits for some LTE rate coefficients are given in
the Appendix.Comment: 12 pages, 14 figures, 3 tables; published on ApJS 2011, 193,
Electrical conductivity as a tool to evaluate the various recharges of a karst aquifer
Karst, hydrogeology, electrical conductivity, Classical Karst Region
Endograft repair for pseudoaneurysms and penetrating ulcers of the ascending aorta
OBJECTIVE: The aim of this paper is to report midterm results of thoracic endovascular aortic repair (TEVAR) for ascending aortic pseudoaneurysms (AAPs) and penetrating aortic ulcers (PAUs) of the ascending aorta. METHODS: This study was retrospective and performed at tertiary centers. Eight patients with AAPs (n = 5) and PAUs (n = 3) received total endovascular repair of the ascending aorta. Patients with a history of type A aortic dissection or fusiform aneurysm were excluded. All patients analyzed were considered to be at high risk for open repair at the time of presentation. RESULTS: Urgent intervention was performed in 6 (75%) cases. Primary clinical success was achieved in 7 (87.5%) cases. A low-flow type 3 endoleak remained asymptomatic and was managed conservatively. No TEVAR-related in-hospital mortality, primary conversion, cerebrovascular accidents, valve impairment, or myocardial infarction occurred. All patients were discharged home, alive and independent, after a median length of stay of 6 (range: 5-24) days. No patient was lost at a mean follow-up of 40 \ub1 33 (range: 4-93) months. Ongoing primary clinical success was maintained in all but 1 patient (type 3 endoleak): aortically related reintervention was never required. No endograft breakage or migration was observed. At 1-year follow-up, 7 (87.5%) aortic lesions had significant reduction in diameter ( 655 mm). CONCLUSIONS: Ascending TEVAR was feasible, safe, and effective for AAPs and PAUs. In a very select subset of lesions, midterm results were favorable, with both standard and custom-designed endografts
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