1,527 research outputs found
La lavorazione della lana nella bassa pianura del Po: dai pesi da telaio al paesaggio di etĂ romana
The archaeological discoveries of the Roman age in the Lower Po Valley (from Mantova to Rovigo and from Brescello to Ferrara) emphasize the great number of fictile loom weights, which testify the wool manufacture in this territory on the edge of the centuriations and occupied by a landscape with grass, wood and marshes.
The loom weights of the land around the Po river have often a face with a decoration impressed by a mould.
This decoration consists in a figurative iconography, whose significance is dealt with in this paper. In some weights it is possible to identify the wool weaver at the loom, and particularly the vertical loom with the warp-yarns and other accessory elements.
In many weights the decoration is an inscription in capital letters, with an onomastic formula: names of ingenui or slaves. Sometimes they are referred to as figuli, “potters”; their role in the textile production is discussed in this paper.
The distribution of the discoveries and the rural character of the settlement lead us to assume that in this territory the textile activity was mainly intended for the domestic requirements
Spontaneous polarization and piezoelectricity in boron nitride nanotubes
Ab initio calculations of the spontaneous polarization and piezoelectric
properties of boron nitride nanotubes show that they are excellent
piezoelectric systems with response values larger than those of piezoelectric
polymers. The intrinsic chiral symmetry of the nanotubes induces an exact
cancellation of the total spontaneous polarization in ideal, isolated nanotubes
of arbitrary indices. Breaking of this symmetry by inter-tube interaction or
elastic deformations induces spontaneous polarization comparable to those of
wurtzite semiconductors.Comment: 5 pages in PRB double column format, 3 figure
First principle theory of correlated transport through nano-junctions
We report the inclusion of electron-electron correlation in the calculation
of transport properties within an ab initio scheme. A key step is the
reformulation of Landauer's approach in terms of an effective transmittance for
the interacting electron system. We apply this framework to analyze the effect
of short range interactions on Pt atomic wires and discuss the coherent and
incoherent correction to the mean-field approach.Comment: 5 pages, 3 figure
Cochlear Implant Outcomes and Genetic Mutations in Children with Ear and Brain Anomalies
Background. Specific clinical conditions could compromise cochlear implantation outcomes and drastically reduce the chance of an acceptable development of perceptual and linguistic capabilities. These conditions should certainly include the presence of inner ear malformations or brain abnormalities. The aims of this work were to study the diagnostic value of high resolution computed tomography (HRCT) and magnetic resonance imaging (MRI) in children with sensorineural hearing loss who were candidates for cochlear implants and to analyse the anatomic abnormalities of the ear and brain in patients who underwent cochlear implantation. We also analysed the effects of ear malformations and brain anomalies on the CI outcomes, speculating on their potential role in the management of language developmental disorders. Methods. The present study is a retrospective observational review of cochlear implant outcomes among hearing-impaired children who presented ear and/or brain anomalies at neuroimaging investigations with MRI and HRCT. Furthermore, genetic results from molecular genetic investigations (GJB2/GJB6 and, additionally, in selected cases, SLC26A4 or mitochondrial-DNA mutations) on this study group were herein described. Longitudinal and cross-sectional analysis was conducted using statistical tests. Results. Between January 1, 1996 and April 1, 2012, at the ENT-Audiology Department of the University Hospital of Ferrara, 620 cochlear implantations were performed. There were 426 implanted children at the time of the present study (who were <18 years). Among these, 143 patients (64 females and 79 males) presented ear and/or brain anomalies/lesions/malformations at neuroimaging investigations with MRI and HRCT. The age of the main study group (143 implanted children) ranged from 9 months and 16 years (average = 4.4; median = 3.0). Conclusions. Good outcomes with cochlear implants are possible in patients who present with inner ear or brain abnormalities, even if central nervous system anomalies represent a negative prognostic factor that is made worse by the concomitant presence of cochlear malformations. Common cavity and stenosis of the internal auditory canal (less than 2 mm) are negative prognostic factors even if brain lesions are absent
Variance Reduction with Monte Carlo Estimates of Error Rates in Multivariate Classification
In this paper, control variates are proposed to speed up Monte Carlo Simulations to estimate expected error rates in multivariate classification
Evidence for pseudogap and phase-coherence gap separation by Andreev reflection experiments in Au/La_{2-x}Sr_{x}CuO_4 point-contact junctions
We present new Au/La_{2-x}Sr_{x}CuO_{4} (LSCO) point-contact conductance
measures as a function of voltage and temperature in samples with 0.08 <= x <=
0.2. Andreev reflection features disappear at about the bulk Tc, giving no
evidence of gap for T > Tc. The fit of the normalized conductance at any T < Tc
supports a (s + d)-wave symmetry of the gap, whose dominant low-T s component
follows the Tc(x) curve in contrast with recent angle-resolved photoemission
spectroscopy and quasiparticle tunneling data. These results prove the
separation between pseudogap and phase-coherence superconducting gap in LSCO at
x <= 0.2.Comment: 4 pages, 4 eps figures, 1 table (RevTeX). Labels added to Fig. 1;
Fig. 3 resized; references added; short discussion about ballistic contact
regime adde
Surface nano-patterning through styrene adsorption on Si(100)
We present an ab initio study of the structural and electronic properties of
styrene molecules adsorbed on the dimerized Si(100) surface at different
coverages, ranging from the single-molecule to the full monolayer. The
adsorption mechanism primarily involves the vinyl group via a [2+2]
cycloaddition process that leads to the formation of covalent Si-C bonds and a
local surface derelaxation, while it leaves the phenyl group almost
unperturbed. The investigation of the functionalized surface as a function of
the coverage (e.g. 0.5 -- 1 ML) and of the substrate reconstruction reveals two
major effects. The first results from Si dimer-vinyl interaction and concerns
the controlled variation of the energy bandgap of the interface. The second is
associated to phenyl-phenyl interactions, which gives rise to a regular pattern
of electronic wires at surface, stemming from the pi-pi coupling. These
findings suggest a rationale for tailoring the surface nano-patterning of the
surface, in a controlled way.Comment: 19 pages (preprint), 4 figures, supplementary materia
High availability using virtualization - 3RC
High availability has always been one of the main problems for a data center.
Till now high availability was achieved by host per host redundancy, a highly
expensive method in terms of hardware and human costs. A new approach to the
problem can be offered by virtualization. Using virtualization, it is possible
to achieve a redundancy system for all the services running on a data center.
This new approach to high availability allows the running virtual machines to
be distributed over a small number of servers, by exploiting the features of
the virtualization layer: start, stop and move virtual machines between
physical hosts. The 3RC system is based on a finite state machine, providing
the possibility to restart each virtual machine over any physical host, or
reinstall it from scratch. A complete infrastructure has been developed to
install operating system and middleware in a few minutes. To virtualize the
main servers of a data center, a new procedure has been developed to migrate
physical to virtual hosts. The whole Grid data center SNS-PISA is running at
the moment in virtual environment under the high availability system.Comment: 10 page
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