178,921 research outputs found
Molecular dissociation in hot, dense hydrogen
No full textWe present a path-integral Monte Carlo study of dissociation in dense hydrogen (1.75 less than or equal to r(s) less than or equal to 2.2 with r(s) the Wigner sphere radius). As the temperature is lowered from 10(5) to 5000 K, a molecular hydrogen gas forms spontaneously from a neutral system of protons and electrons. At high density, r(s) < 2.0, thermally activated dissociation is accompanied by decreasing pressure, signaling the presence of a first order transition and critical point. The decrease in electron kinetic energy during dissociation is responsible for the pressure decrease and transition. At lower density the phase transition disappears
UN APPROCCIO GRID NELL’ANALISI E NELLA RICERCA DI LESIONI IN UN DATABASE DI IMMAGINI MAMMOGRAFICHE DISTRIBUITE
No full textOrbit determination of space debris using a bi-static radar configuration with a multiple-beam receiver
No full textIn this work the use of a multi-beaming radar system is analyzed and a possible setup of a closed loop system (i.e. from measurement and data acquisition to orbit determination) is described. The Orbit Determination (OD) algorithms are specialized for a bistatic radar configuration where the Medicina Northern Cross radio-telescope (owned by the University of Bologna-Italy) is considered as a receiver. The Northern Cross is composed of two perpendicular arms: the E/W arm is 564 m long and consists in a single cylindrical antenna with a width of 29.4 m, whereas the N/S arm is made of 64 parallel antennas with a length of 22.6 m and a width of 7.5 m. The collecting area reaches 27,400 sqm and, by considering a complete upgrade of the radar with the installation of new receivers on the focal lines, up to 22,880 possible theoretical independent beams could cover the field-of-view of 55.47 (E/W) deg x 1.8 (N/S) deg. By looking at the sequence of beams that are illuminated, it is thus possible to estimate, with an higher level of detail with respect to the single-beam system, the ground track of the transiting object. Given this peculiar system, tailored orbit determination algorithms have to be developed. The orbit determination algorithm receives as input the data processed by the acquisition system, that digitally assembles measured radar echoes, using Fast Fourier Transform, to provide the signal for each beam. These inputs are the measured Doppler shift, time delay, the illumination time and measured power intensity associated to each beam. By combining these information with the knowledge of beam distribution and pointing it is possible to refine the orbital parameters of known objects or to perform a preliminary OD. A few LEO objects are considered to generate simulated data that are then used to feed the developed OD algorithms. In this way the performances of the algorithms can be tested and the effectiveness of this innovative configuration for space debris measurements, that couples a bistatic radar and a multi-beaming receiver, can be assessed
Diagnostic utility of cyclin D1 in the diagnosis of small round blue cell tumors in children and adolescents: beware of cyclin D1 expression in clear cell sarcoma of the kidney and CIC-DUX4 fusion–positive sarcomas. Comment on Magro et al (2016)—reply
No full textAppropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Bayesian Network Based Classification of Mammography Structured Reports
No full textn modern medical domain, documents are created directly in electronic form and stored on huge databases contain- ing documents, text in integral form and images. Retrieving right informations from these servers is challenging and, sometimes, this is very time consuming. Current medical technology do not provide a smart methodology classification of such documents based on their content. In this work the radiological structured reports are analysed classified and assigning an appropriate label. The text classifier is used to label a mammographic structured report. The experimental data are real clinical report coming from a hospital server. Analysing the structured report content, the classifier labels the patient structured report as healthy or pathological. The present work uses Information Retrieval techniques to improve the classification process. These technique provide a light semantic analysis to remove negative terms, a removing stop-word step and, finally, a thesaurus is used to uniform used words. The structured reports are classified using a Bayes Naive Classifier. The experimental results provide interesting performance in terms of specificity and sensibility. Others two indexes are computed in order to assess system’s robustness: these are the Az (Area under Curve ROC) and σAz (Az standard error)
A novel web service for mammography images indexing
No full textMedical community needs to extract precise information from a large amount of data. These data are a collection of different types such as text documents, images and video. Currently medical technology do not provide an intelligent methodology for documents recovery and classification of such documents based on their content. In this work the radiological structured reports are analysed with the corresponding mammographic images. The presented system is composed of an Indexing Engine and a Searching Engine, based on innovative methods for IR (Information Retrieval). The proposed work is useful for physicians as support diagnosis system, for students as learning support system, and finally, for epidemiological studies. The system allows for submitting a query through a web interface, consulting a structured report and showing associated mammographic images. The dataset is composed of both healthy and pathological patients. The proposed architecture achieved satisfactory results in terms of Sensitivity and Specificity. Three scenarios are presented and described. © 2013 IEEE
Indagini archeologiche e topografiche nella villa romana di contrada Castellito di Ramacca (Catania). Risultati preliminari delle ricerche 2019/2020
No full textL'articolo presenta i risultati preliminari della ricerca archeologica avviata nella villa romana di contrada Castellito, ampia area che si estende nel settore nord orientale del territorio di Ramacca (Catania, Sicilia orientale). Il sito costituisce uno dei pochi contesti riconducibili a una ricca residenza di età imperale situata nei margini occidentali della Piana di Catania. La villa occupa la sommità di un basso poggio (106 m slm) situato nei pressi del fiume Dittaino, che scorre immediatamente a est; a nord, ai piedi di un’altra collina, era stata in passato segnalata la presenza di tombe a fossa rivestite di scaglie di pietra, probabilmente pertinenti a una necropoli coeva alla villa romana; le ricognizioni recentemente condotte nell’area non hanno consentito, tuttavia, di identificare le sepolture, probabilmente obliterate dalla coltivazione di una cava di calcarenite avviata nell’area negli ultimi decenni. L'articolo fornisce una dettagliata relazione sullo stato dei mosaici e delle strutture, analizzando il sito nel suo contesto topografico
Enzyme-iron nanoparticle direct interactions: complex formation and application for a coulometric biosensor for aminoaldehydes
No full textRecombinant aminoaldehyde dehydrogenase from tomato (LeAMADH1) was used as a model protein for studying the intimate interaction at the interface between proteins and surface active maghemite nanoparticles (SAMNs). SAMNs represent a new class of maghemite nanoparticles, displaying great colloidal behavior and specific surface chemical properties, as well as, peculiar electrochemical characteristics and specificity toward protein binding [1-2]. A potential anchor zone was individuated in a carboxylic rich surface area of the protein structure by molecular modeling. LeAMADH1 was successfully bound to the surface of bare SAMNs and its enzymatic activity was preserved, leading to a magnetic drivable enzymatic hybrid (SAMN@LeAMADH1). The catalytic parameters of SAMN@LeAMADH1 were determined, and exploited for the construction of a coulometric biosensor for the determination of aminoaldehydes in alcoholic beverages. A suspension of SAMN@LeAMADH1, used inside a low volume (1 μL) electrochemical flow cell, fabricated in-house, led to the complete oxidation of aminoaldehydes, producing a correspondent amount of NADH. The hybrid nanomaterial was magnetically removed after the enzymatic reaction allowing its reutilization. At the same time, a SAMN modified carbon paste electrode, inserted in the microcell was used for the direct electro-oxidation of NADH, leading to the coulometric determination of NADH produced during the enzymatic process. The novel biosensor showed a series of peculiarities: a) SAMN modified carbon paste electrode was used for NADH electro-oxidation; b) the complete enzymatic oxidation of sample aminoaldehydes, producing NADH, was carried out in a colloidal suspension, inside a low volume electrochemical flow cell, optimizing reactant diffusion; c) NADH, produced during the complete enzymatic oxidation of aminoaldehydes, was coulometrically determined at the SAMN modified lectrode; d) the capture of the hybrid, by the application of an external magnet, makes it reusable. 1)Baratella et al., Biosensors and Bioelectronics, 2013, 45, 13–18. 2)Magro et al., Biosensors and Bioelectronics, 2014, 52, 159–165
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
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