541 research outputs found
Mobile classroom recorder
Nel progetto Mobile Classroom Recorder si sviluppato un supporto
informatico per la registrazione audio e video delle lezioni universitarie
senza l\u2019intervento di un tecnico di regia e con limitata post-produzione. Si
presenta l\u2019architettura hardware e software del sistema che consente di
registrare e comprimere in tempo reale il video di una lezione. Il sistema \ue8
facilmente trasportabile da un aula all\u2019altra in diversi momenti della
didattica dei corsi di laurea. Il progetto \ue8 orientato all\u2019archiviazione delle
lezioni registrate, per la loro successiva fruizione, a vantaggio degli
studenti: in particolare di studenti disabili, studenti lavoratori, malattie,
carenze di mezzi di trasporto ecc
Subtelomeric I-scei-mediated Double-strand Breaks Are Repaired By Homologous Recombination In Trypanosoma Cruzi
Fundação de Amparo Ă Pesquisa do Estado de SĂŁo Paulo (FAPESP)Fundação de Amparo Ă Pesquisa do Estado de SĂŁo Paulo (FAPESP)Conselho Nacional de Desenvolvimento CientĂfico e TecnolĂłgico (CNPq)Trypanosoma cruzi chromosome ends are enriched in surface protein genes and pseudogenes (e.g., trans-sialidases) surrounded by repetitive sequences. It has been proposed that the extensive sequence variability among members of these protein families could play a role in parasite infectivity and evasion of host immune response. In previous reports we showed evidence suggesting that sequences located in these regions are subjected to recombination. To support this hypothesis we introduced a double-strand break (DSB) at a specific target site in a T. cruzi subtelomeric region cloned into an artificial chromosome (pTAC). This construct was used to transfect T. cruzi epimastigotes expressing the I-SceI meganuclease. Examination of the repaired sequences showed that DNA repair occurred only through homologous recombination (HR) with endogenous subtelomeric sequences. Our findings suggest that DSBs in subtelomeric repetitive sequences followed by HR between them may contribute to increased variability in T. cruzi multigene families. Š 2016 Chiurillo, Moraes Barros, Souza, Marini, Antonio, Cortez, Curto, Lorenzi, Schijman, Ramirez and da Silveira.7DEC11/51475-3, FAPESP, Fundação de Amparo Ă Pesquisa do Estado de SĂŁo Paulo11/51693-0, FAPESP, Fundação de Amparo Ă Pesquisa do Estado de SĂŁo Paulo306591/2015-4, CNPq, Conselho Nacional de Desenvolvimento CientĂfico e TecnolĂłgicoFundação de Amparo Ă Pesquisa do Estado de SĂŁo Paulo (FAPESP)Fundação de Amparo Ă Pesquisa do Estado de SĂŁo Paulo (FAPESP)Conselho Nacional de Desenvolvimento CientĂfico e TecnolĂłgico (CNPq
Multi-gap superconductivity in a BaFe1.84Co0.16As2 film from optical measurements at terahertz frequencies
We measured the THz reflectance properties of a high quality epitaxial thin
film of the Fe-based superconductor BaFeCoAs with
T=22.5 K. The film was grown by pulsed laser deposition on a DyScO
substrate with an epitaxial SrTiO intermediate layer. The measured
spectrum, i.e. the reflectivity ratio between the superconducting and
normal state reflectance, provides clear evidence of a superconducting gap
close to 15 cm. A detailed data analysis shows that a
two-band, two-gap model is absolutely necessary to obtain a good description of
the measured spectrum. The low-energy gap results to be
well determined (=15.50.5 cm), while the value of the
high-energy gap is more uncertain (=557 cm).
Our results provide evidence of a nodeless isotropic double-gap scenario, with
the presence of two optical gaps corresponding to 2 values close
to 2 and 7.Comment: Published Versio
Measurement of (anti)deuteron and (anti)proton production in DIS at HERA
The first observation of (anti)deuterons in deep inelastic scattering at HERA
has been made with the ZEUS detector at a centre-of-mass energy of 300--318 GeV
using an integrated luminosity of 120 pb-1. The measurement was performed in
the central rapidity region for transverse momentum per unit of mass in the
range 0.3<p_T/M<0.7. The particle rates have been extracted and interpreted in
terms of the coalescence model. The (anti)deuteron production yield is smaller
than the (anti)proton yield by approximately three orders of magnitude,
consistent with the world measurements.Comment: 26 pages, 9 figures, 5 tables, submitted to Nucl. Phys.
Forward jet production in deep inelastic ep scattering and low-x parton dynamics at HERA
Differential inclusive jet cross sections in neutral current deep inelastic
ep scattering have been measured with the ZEUS detector. Three phase-space
regions have been selected in order to study parton dynamics where the effects
of BFKL evolution might be present. The measurements have been compared to the
predictions of leading-logarithm parton shower Monte Carlo models and
fixed-order perturbative QCD calculations. In the forward region, QCD
calculations at order alpha_s^1 underestimate the data up to an order of
magnitude at low x. An improved description of the data in this region is
obtained by including QCD corrections at order alpha_s^2, which account for the
lowest-order t-channel gluon-exchange diagrams, highlighting the importance of
such terms in parton dynamics at low x.Comment: 25 pages, 4 figure
Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV
Results are presented from a search for a W' boson using a dataset
corresponding to 5.0 inverse femtobarns of integrated luminosity collected
during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV.
The W' boson is modeled as a heavy W boson, but different scenarios for the
couplings to fermions are considered, involving both left-handed and
right-handed chiral projections of the fermions, as well as an arbitrary
mixture of the two. The search is performed in the decay channel W' to t b,
leading to a final state signature with a single lepton (e, mu), missing
transverse energy, and jets, at least one of which is tagged as a b-jet. A W'
boson that couples to fermions with the same coupling constant as the W, but to
the right-handed rather than left-handed chiral projections, is excluded for
masses below 1.85 TeV at the 95% confidence level. For the first time using LHC
data, constraints on the W' gauge coupling for a set of left- and right-handed
coupling combinations have been placed. These results represent a significant
improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe
Search for new physics in events with opposite-sign leptons, jets, and missing transverse energy in pp collisions at sqrt(s) = 7 TeV
A search is presented for physics beyond the standard model (BSM) in final
states with a pair of opposite-sign isolated leptons accompanied by jets and
missing transverse energy. The search uses LHC data recorded at a
center-of-mass energy sqrt(s) = 7 TeV with the CMS detector, corresponding to
an integrated luminosity of approximately 5 inverse femtobarns. Two
complementary search strategies are employed. The first probes models with a
specific dilepton production mechanism that leads to a characteristic kinematic
edge in the dilepton mass distribution. The second strategy probes models of
dilepton production with heavy, colored objects that decay to final states
including invisible particles, leading to very large hadronic activity and
missing transverse energy. No evidence for an event yield in excess of the
standard model expectations is found. Upper limits on the BSM contributions to
the signal regions are deduced from the results, which are used to exclude a
region of the parameter space of the constrained minimal supersymmetric
extension of the standard model. Additional information related to detector
efficiencies and response is provided to allow testing specific models of BSM
physics not considered in this paper.Comment: Replaced with published version. Added journal reference and DO
Silicon and Germanium Nanostructures for Photovoltaic Applications: Ab-Initio Results
Actually, most of the electric energy is being produced by fossil fuels and great is the search for viable alternatives. The most appealing and promising technology is photovoltaics. It will become truly mainstream when its cost will be comparable to other energy sources. One way is to significantly enhance device efficiencies, for example by increasing the number of band gaps in multijunction solar cells or by favoring charge separation in the devices. This can be done by using cells based on nanostructured semiconductors. In this paper, we will present ab-initio results of the structural, electronic and optical properties of (1) silicon and germanium nanoparticles embedded in wide band gap materials and (2) mixed silicon-germanium nanowires. We show that theory can help in understanding the microscopic processes important for devices performances. In particular, we calculated for embedded Si and Ge nanoparticles the dependence of the absorption threshold on size and oxidation, the role of crystallinity and, in some cases, the recombination rates, and we demonstrated that in the case of mixed nanowires, those with a clear interface between Si and Ge show not only a reduced quantum confinement effect but display also a natural geometrical separation between electron and hole
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