1,654 research outputs found
Navier-Stokes analysis of transonic cascade flow
A new kind of C-type grid is proposed, this grid is non-periodic on the wake and allows minimum skewness for cascades with high turning and large camber. Reynolds-averaged Navier-Stokes equations are solved on this type of grid using a finite volume discretization and a full multigrid method which uses Runge-Kutta stepping as the driving scheme. The Baldwin-Lomax eddy-viscosity model is used for turbulence closure. A detailed numerical study is proposed for a highly loaded transonic blade. A grid independence analysis is presented in terms of pressure distribution, exit flow angles, and loss coefficient. Comparison with experiments clearly demonstrates the capability of the proposed procedure
Multigrid calculation of three-dimensional viscous cascade flows
A 3-D code for viscous cascade flow prediction was developed. The space discretization uses a cell-centered scheme with eigenvalue scaling to weigh the artificial dissipation terms. Computational efficiency of a four stage Runge-Kutta scheme is enhanced by using variable coefficients, implicit residual smoothing, and a full multigrid method. The Baldwin-Lomax eddy viscosity model is used for turbulence closure. A zonal, nonperiodic grid is used to minimize mesh distortion in and downstream of the throat region. Applications are presented for an annular vane with and without end wall contouring, and for a large scale linear cascade. The calculation is validated by comparing with experiments and by studying grid dependency
N=1* model superpotential revisited (IR behaviour of N=4 limit)
The one-loop contribution to the superpotential, in particular the
Veneziano-Yankielowicz potential in N=1 supersymmetric Yang-Mills model is
discussed from an elementary field theory method and the matrix model point of
view. Both approaches are based on the Renormalization Group variation of the
superconformal N=4 supersymmetric Yang-Mills model.Comment: 31 page
The Role of Guarantees in support of Entrepreneurial Microcredit in Italy.
This paper proposes an empirical analysis of the microcredit initiatives promoted by local and cooperative credit banks trying to take advantage of any differences in the initiatives promoted by other types of operators in terms of default rates of loans. The differences are analyzed on the basis of distinctive features to identify a possible way of developing microcredit in Italy. The empirical analysis verifies the existence of a statically significant correlation between characteristics of the entrepreneurial microcredit programs and their default risk. The presence of credit guarantee schemes and the role of banking intermediaries as promoters reduce significantly the risk of default on these initiatives. The Italian microcredit programs do not show territorial differences.
A new species of Bolbelasmus Boucomont, 1911 (Insecta Coleoptera Geotrupidae) from Sicily (Italy).
Authors have examined all available sicilian specimens belonging to the genus Bolbelasmus, collected between 1893 and 2010, previously identified as B. gallicus e B. unicornis. They conclude that both species have to be excluded from the sicilian fauna and describe the new species B. romanorum, which is characterized by peculiar punctures on the clypeus, the head and the pronotum, and by the shape of the clypeus, the head and the aedeagus sclerites. They compare the new species with all the taxa currently known in the Mediterranean. Further, they show oscillograms of both sexes of the new species, which, as other Bolbelasmus, stridulates vigorously; they also detect for the first time the pars stridens, consisting in a series of small bristles on the lower outer border of wings; the insect emits its sound moving actively the abdomen, the friction of the wing on the first abdominal tergite, particularly swollen, produces the stridulation
Bio-logic: gene expression and the laws of combinatorial logic
Original article can be found at: http://www.mitpressjournals.org/ Copyright MIT Press DOI: 10.1162/artl.2008.14.1.121At the heart of the development of fertilized eggs into fully formed organisms and the adaptation of cells to changed conditions are genetic regulatory networks (GRNs). In higher multi-cellular organisms, signal selection and multiplexing is performed at the cis-regulatory domains of genes, where combinations of transcription factors (TFs) regulate the rates at which the genes are transcribed into mRNA. To be able to act as activators or repressors of gene transcription, TFs must first bind to target sequences on the regulatory domains. Two TFs that act in concert may bind entirely independently of each other, but more often binding of the first one will alter the affinity of the other for its binding site. This paper presents a systematic investigation into the effect of TF binding dependencies on the predicted regulatory function of this “bio-logic”. Four extreme scenarios, commonly used to classify enzyme activation and inhibition patterns, for the binding of two TFs were explored: independent (the TFs bind without affecting each other’s affinities), competitive (the TFs compete for the same binding site), ordered (the TFs bind in a compulsory order), and joint binding (the TFs either bind as a preformed complex, or binding of one is virtually impossible in the absence of the other). The conclusions are: 1) the laws of combinatorial logic hold only for systems with independently binding TFs; 2) systems formed according to the other scenarios can mimic the functions of their Boolean logical counterparts, but cannot be combined or decomposed in the same way; and 3) the continuously scaled output of systems consisting of competitively binding activators and repressors can be more robustly controlled than that of single TF or (quasi-) logical multi-TF systems. Keywords: Transcription regulation, Genetic regulatory networks, Enzyme kinetics, Combinatorial logic, Non-Boolean continuous logic, Modelling.Peer reviewe
Il ruolo delle banche locali e del relationship lending in scenari economici in profondo cambiamento
Lo scopo di questo lavoro \ue8 quello di esaminare la relazione tra banca locale e impresa in un contesto
economico in profondo cambiamento. L\u2019obiettivo \ue8 comprendere se e come l\u2019orientamento all\u2019attivit\ue0 di finanziamento
delle banche locali (pi\uf9 radicate nel territorio e pi\uf9 vicine ai principi del relationship lending) sia cambiato in seguito
allo scoppio della crisi finanziaria
EUROPE 2020 SI-LAB: A New Center for Economic and Social Development in Sicily
The debate on the determinants of regional and local development has been stimulated
recently by the European strategy for smart, sustainable and inclusive growth defined as Europe 2020.
We present the objectives and structure of a new laboratory (SI-LAB) for the development of Sicilian
economy promoted by the University of Palermo. In particular, we highlight the fundamental issues
related to the incoming functioning of the Lab as a new oganization devoted to analyzing public
policy issues, and fostering new ways of entrepreurship at the local level
Colour, copies and confinement
In this paper we construct a wide class of Gribov copies in Coulomb gauge
SU(2) gauge theory. Infinitesimal copies are studied in some detail and their
non-perturbative nature is made manifest. As an application it is shown that
the copies prevent a non-perturbative definition of colour charge.Comment: 25 pages, 10 figures. Minor changes, two references added. Published
versio
The genus Bolbelasmus in the western and southern regions of the Mediterranean Basin (Coleoptera: Geotrupidae: Bolboceratinae)
The Bolbelasmus Boucomont, 1911 species of the western and southern
regions of the Mediterranean Basin (Northern Africa, Iberian Peninsula and
France) are revised. The following three new species are described: Bolbelasmus
brancoi Hillert & Král sp. nov. and Bolbelasmus howdeni Hillert & Král sp. nov.,
both from Spain and Gibraltar, and Bolbelasmus nikolajevi Hillert, Arnone, Král &
Massa sp. nov. from Egypt, Libya and Tunisia. Bolbelasmus vaulogeri (Abeille de
Perrin, 1898) stat. restit. is removed from synonymy with B. bocchus (Erichson,
1841) and reinstated as a separate species. Bolbelasmus romanorum Arnone &
Massa, 2010 is considered a junior subjective synonym of B. vaulogeri. Lectotypes
for Bolboceras bocchus Erichson, 1841 and Bolboceras vaulogeri Abeille
de Perrin, 1898 are designated. Relevant diagnostic characters (head, pronotum,
elytron, external male genitalia) are illustrated. Identifi cation keys for both males
and females, and an annotated list of the Western Palaearctic representatives of the
genus Bolbelasmus are presented. Finally, fi rst records are given for B. gallicus
(Mulsant, 1842) from Corsica and the Midi-Pyrénées region of France, B. keithi
Miessen & Trichas, 2011 from the Greek island of Rhodes, and B. unicornis
(Schrank von Paula, 1789) from the Tuscany province of Italy
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