445 research outputs found
Elementos Arquiteturais do Substrato da Lagoa dos Patos Revelados por SĂsmica de Alta Resolução
A high-resolution seismic survey was performed on the Lagoa dos Patos, southern Brazil. The survey was conducted aboard the research vessel LARUS of the Fundação Universidade Federal do Rio Grande. The seismic profiles were obtained using a 3.5 kilohertz frequency, which provided a rather good penetration depth and resolution of the records. Results of the seismic records allowed the determination and mapping of seismic facies and seismic sequences, as well as related architectural elements, which were identified basically through the configuration patterns of the seismic reflectors. The analysis of the seismic records allowed the identification of the architectural elements that build up the sedimentary pile accumulated in the coastal prism of the State of Rio Grande do Sul, contributing to a better understanding of the geological evolution of the southern Brazilian coastal plain during the Quaternary period.Fil: Weschenfelder, Jair. Universidade Federal do Rio Grande do Sul; BrasilFil: CorrĂȘa, Iran C. S.. Universidade Federal do Rio Grande do Sul; BrasilFil: Aliotta, Salvador. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto Argentino de OceanografĂa. Universidad Nacional del Sur. Instituto Argentino de OceanografĂa; Argentin
Progetto di una banca dati multidisciplinare: il progetto europeo VOLUME come caso di studio
Il presente lavoro si pone come obiettivo la realizzazione di una banca dati multi-parametrica in grado
di archiviare diverse tipologie di dato strumentale. Il sistema proposto, accessibile dal portale dellâINGV
della sezione di Catania al link âaltre INGV-CTâ del menĂč âBanche datiâ, studiato e collaudato allâinterno
del progetto europeo VOLUME (http://www.volume-project.net/), consente la fruizione dei dati messi a
disposizione dalle diverse unitĂ funzionali dellâINGV della sezione di Catania coinvolte nel progetto. I dati,
disponibili ai partner del progetto, sono accessibili previa registrazione e successiva validazione dellâutente.
Lâobiettivo principale di tale progetto Ăš quello di studiare le dinamiche vulcaniche in modo da
identificare e caratterizzare fenomeni che possano essere interpretati come possibili precursori di eruzioni.
Per perseguire tale obiettivo occorre analizzare ed integrare diverse tipologie di misure, da quelle geofisiche
a quelle geochimiche, con il fine di raggiungere una migliore comprensione dei processi in atto allâinterno
delle aree caratterizzate da vulcanismo attivo. Sebbene i dati archiviati siano relativi al solo vulcano Etna ed
il periodo analizzato Ăš relativo agli anni 2002-2003 , il sistema proposto puĂČ essere impiegato per la gestione
di dati relativi ad altri vulcani e attinenti a qualsiasi intervallo temporale. Il sistema Ăš stato realizzato in modo
da fornire una interfaccia web user friendly che permetta agli utenti la navigazione, la visualizzazione e il
download dei dati memorizzati allâinterno della banca dati.
Nei paragrafi successivi verrĂ presentata una panoramica delle funzionalitĂ implementate per la
navigazione del database. In particolare, i dati trattati nel presente report sono stati prodotti e forniti dalle
unitĂ funzionali dellâINGV della sezione di Catania (http://www.ct.ingv.it) che hanno partecipato al progetto
VOLUME:
âą UnitĂ Funzionale Sismologia;
âą UnitĂ Funzionale Vulcanologia e Geochimica;
âą UnitĂ Funzionale Gravimetria e Magnetismo;
âą UnitĂ Funzionale Deformazione e Geodesia
Role of virtual break-up of projectile in astrophysical fusion reactions
We study the effect of virtual Coulomb break-up, commonly known as the dipole
polarizability, of the deuteron projectile on the astrophysical fusion reaction
3He(d,p)4He. We use the adiabatic approximation to estimate the potential shift
due to the E1 transition to the continuum states in the deuteron, and compute
the barrier penetrability in the WKB approximation. We find that the
enhancement of the penetrability due to the deuteron break-up is too small to
resolve the longstanding puzzle observed in laboratory measurements that the
electron screening effect is surprisingly larger than theoretical prediction
based on an atomic physics model. The effect of the 3He break-up in the
3He(d,p)4He reaction, as well as the 7Li break-up in the 7Li(p,alpha)4He
reaction is also discussed.Comment: 9 pages, 2 eps figure
Influence of tumor microenvironment and fibroblast population plasticity on melanoma growth, therapy resistance and immunoescape
Cutaneous melanoma (CM) tissue represents a network constituted by cancer cells and tumor microenvironment (TME). A key feature of CM is the high structural and cellular plasticity of TME, allowing its evolution with disease and adaptation to cancer cell and environmental alter-ations. In particular, during melanoma development and progression each component of TME by interacting with each other and with cancer cells is subjected to dramatic structural and cellular modifications. These alterations affect extracellular matrix (ECM) remodelling, phenotypic profile of stromal cells, cancer growth and therapeutic response. The stromal fibroblast populations of the TME include normal fibroblasts and melanomaâassociated fibroblasts (MAFs) that are highly abun-dant and flexible cell types interacting with melanoma and stromal cells and differently influencing CM outcomes. The shift from the normal microenvironment to TME and from normal fibroblasts to MAFs deeply sustains CM growth. Hence, in this article we review the features of the normal mi-croenvironment and TME and describe the phenotypic plasticity of normal dermal fibroblasts and MAFs, highlighting their roles in normal skin homeostasis and TME regulation. Moreover, we dis-cuss the influence of MAFs and their secretory profiles on TME remodelling, melanoma progres-sion, targeted therapy resistance and immunosurveillance, highlighting the cellular interactions, the signalling pathways and molecules involved in these processes
Neutron Tomography at INES: First experimental results
A neutron tomography apparatus has been designed and installed at the Italian neutron experimental station (INES) at ISIS (UK). The instrument has a double aim: an additional opportunity for the INES users and a âbench testâ for an instrument component that will be proposed for installation on some of the new neutron scattering instruments of Target Station 2 (TS2) of ISIS. Here, we present the first experimental results achieved with this apparatus
Fusion rate enhancement due to energy spread of colliding nuclei
Experimental results for sub-barrier nuclear fusion reactions show cross
section enhancements with respect to bare nuclei which are generally larger
than those expected according to electron screening calculations. We point out
that energy spread of target or projectile nuclei is a mechanism which
generally provides fusion enhancement. We present a general formula for
calculating the enhancement factor and we provide quantitative estimate for
effects due to thermal motion, vibrations inside atomic, molecular or crystal
system, and due to finite beam energy width. All these effects are marginal at
the energies which are presently measurable, however they have to be considered
in future experiments at still lower energies. This study allows to exclude
several effects as possible explanation of the observed anomalous fusion
enhancements, which remain a mistery.Comment: 17 pages with 3 ps figure included. Revtex styl
Data mining in the context of monitoring Mt Etna, Italy
The persistent volcanic activity of Mt Etna makes the continuous monitoring of multidisciplinary data a ïŹrst-class
issue. Indeed, the monitoring systems rapidly accumulate huge quantity of data, arising speciïŹc problems of an-
dling and interpretation. In order to respond to these problems, the INGV staff has
developed a number of software tools for data mining. These tools have the scope of identifying structures in the
data that can be related to volcanic activity, furnishing criteria for the identiïŹcation of precursory scenarios. In
particular, we use methods of clustering and classiïŹcation in which data are divided into groups according to a-
priori-deïŹned measures of similarity or distance. Data groups may assume various shapes, such as convex clouds
or complex concave bodies.The âKKAnalysisâ software package is a basket of clustering methods. Currently, it is
one of the key techniques of the tremor-based automatic alarm systems of INGV Osservatorio Etneo. It exploits
both Self-Organizing Maps and Fuzzy Clustering. Beside seismic data, the software has been applied to the geo-
chemical composition of eruptive products as well as a combined analysis of gas-emission (radon) and seismic
data.
The âDBSCANâ package exploits a concept based on density-based clustering. This method allows discovering
clusters with arbitrary shape. Clusters are deïŹned as dense regions of objects in the data space separated by re-
gions of low density. In DBSCAN a cluster grows as long as the density within a group of objects exceeds some
threshold. In the context of volcano monitoring, the method is particularly promising in the recognition of ash par-
ticles as they have a rather irregular shape. The âMOTIFâ software allows us to identify typical waveforms in time
series, outperforming methods like cross-correlation that entail a high computational effort. MOTIF can recognize
the non-imilarity of two patterns on a small number of data points without going through the whole length of data
vectors.
All the developments aforementioned come along with modules for feature extraction and post-processing. Spe-
ciïŹc attention is devoted to the obustness of the feature extraction to avoid misinterpretations due to the presence
of disturbances from environmental noise or other undesired signals originating from the source, which are not
relevant for the purpose of volcano surveillance
Measurement of the 18Ne(a,p_0)21Na reaction cross section in the burning energy region for X-ray bursts
The 18Ne(a,p)21Na reaction provides one of the main HCNO-breakout routes into
the rp-process in X-ray bursts. The 18Ne(a,p_0)21Na reaction cross section has
been determined for the first time in the Gamow energy region for peak
temperatures T=2GK by measuring its time-reversal reaction 21Na(p,a)18Ne in
inverse kinematics. The astrophysical rate for ground-state to ground-state
transitions was found to be a factor of 2 lower than Hauser-Feshbach
theoretical predictions. Our reduced rate will affect the physical conditions
under which breakout from the HCNO cycles occurs via the 18Ne(a,p)21Na
reaction.Comment: 5 pages, 3 figures, accepted for publication on Physical Review
Letter
Properties and skin compatibility of films based on poly(lactic acid) (PLA) bionanocomposites incorporating chitin nanofibrils (CN)
Nanobiocomposites suitable for preparing skin compatible films by flat die extrusion were prepared by using plasticized poly(lactic acid) (PLA), poly(butylene succinate-co-adipate) (PBSA), and Chitin nanofibrils as functional filler. Chitin nanofibrils (CNs) were dispersed in the blends thanks to the preparation of pre-nanocomposites containing poly(ethylene glycol). Thanks to the use of a melt strength enhancer (Plastistrength) and calcium carbonate, the processability and thermal properties of bionanocomposites films containing CNs could be tuned in a wide range. Moreover, the resultant films were flexible and highly resistant. The addition of CNs in the presence of starch proved not advantageous because of an extensive chain scission resulting in low values of melt viscosity. The films containing CNs or CNs and calcium carbonate resulted biocompatible and enabled the production of cells defensins, acting as indirect anti-microbial. Nevertheless, tests made with Staphylococcus aureus and Enterobacter spp. (Gram positive and negative respectively) by the qualitative agar diffusion test did not show any direct anti-microbial activity of the films. The results are explained considering the morphology of the film and the different mechanisms of direct and indirect anti-microbial action generated by the nanobiocomposite based films
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