1,495 research outputs found
Antiproton annihilation on light nuclei at very low energies
The recent experimental data obtained by the OBELIX group on D and
He total annihilation cross sections are analyzed. The combined
analysis of these data with existing antiprotonic atom data allows, for the
first time, the imaginary parts of the S-wave scattering lengths for the two
nuclei to be extracted. The obtained values are: for D and for He. This
analysis indicates an unexpected behaviour of the imaginary part of the
-nucleus S-wave scattering length as a function of the atomic weight
A: (p) > (D) > (He).Comment: 13 pages, 5 figure
Duo: a general program for calculating spectra of diatomic molecules
Duo is a general, user-friendly program for computing rotational,
rovibrational and rovibronic spectra of diatomic molecules. Duo solves the
Schr\"{o}dinger equation for the motion of the nuclei not only for the simple
case of uncoupled, isolated electronic states (typical for the ground state of
closed-shell diatomics) but also for the general case of an arbitrary number
and type of couplings between electronic states (typical for open-shell
diatomics and excited states). Possible couplings include spin-orbit, angular
momenta, spin-rotational and spin-spin. Corrections due to non-adiabatic
effects can be accounted for by introducing the relevant couplings using
so-called Born-Oppenheimer breakdown curves.
Duo requires user-specified potential energy curves and, if relevant, dipole
moment, coupling and correction curves. From these it computes energy levels,
line positions and line intensities. Several analytic forms plus interpolation
and extrapolation options are available for representation of the curves. Duo
can refine potential energy and coupling curves to best reproduce reference
data such as experimental energy levels or line positions. Duo is provided as a
Fortran 2003 program and has been tested under a variety of operating systems
Avaliação de genótipos de milho no municÃpio de Brasiléia-Acre.
A cultura do milho no municÃpio de Brasiléia, assume significa tiva relevância sócio-econômica, contribuindo com 20,65% na produção global do Estado (CEPA/1988). Além de ser utilizado na alimentação humana e ração animal, o excedente da produção tem sido comercializado no mercado local, em Rio Branco e Cobija, cidade frobteiriça (Bolivia). A cultura apresenta problemas diversos: cultivares pouco produtivas, cultivo em consorcio, grandes espaçamentos entre plantas, cultivares de grande porte, Ãndices elevados de acamamento, doenças, ocorrência de baixa produtividade. Estes problemas têm constituÃdo em fatores limitantes a oferta de milho ao mercado, além de resultar no baixo retorno econômico da pequena produção. Com o objetivo de selecionar cultivares mais produtivas e resistentes aos principais problemas da região, a UEPAE de Rio Branco vem desenvolvendo trabalhos no Núcleo de Pesquisa -Quixadá, localizado em Brasiléia.bitstream/item/117388/1/1158.pd
Distance measurement by delayed optical feedback in a ring laser
We numerically study the behavior of a semiconductor ring laser subject to bidirectional
delayed optical feedback, when the isolated laser is in the quasi-unidirectional regime.
The optical feedback, provided by two external refectors located in front of the ring output waveguides, can modify the laser regime produced by the cross-saturation between
the clockwise and the counter-clockwise mode. Thus, the system exhibits new diferent regimes, most of which are asymmetric and bidirectional, with alternating dominant
mode. Two of these regimes are of special interest in view of applications, because the
laser switching period, between the clockwise and the counter-clockwise mode, is linearly
related to the time of fight from the laser to one or both refectors. In these operating conditions, the laser is thus suitable to implement a telemeter. A convenient electrical output
signal is obtained by a photodiode located behind one (partially refecting) fxed mirror,
or by measuring the voltage drop across the laser junction. Simulations are performed by
mathematical models based on rate-equations, assuming typical literature parameters for a
1 mW ring laser
World Workshop on Oral Medicine VII : What participants perceive as important
Our objective was to identify which aspects of World Workshop on Oral Medicine (WWOM) participation were perceived as significant for participants\u2019 professional development. Online survey was sent to previous WWOM participants. Qualitative analysis of participants\u2019 responses to an open-ended question was performed. Fifty-two WWOM participants responded. Nearly three quarters of respondents (72.3%) felt that participation in the WWOM helped their career. A high percentage of respondents (67.3%) provided answers that fell under the domains of international collaboration, followed by personal academic benefits (48%). Overall, the results indicate that WWOM participation played an important role in individual's professional development. We identified aspects of WWOM involvement that the participants perceived as important. This information will be used for the development of an objective instrument for measuring impact of WWOM on participant's professional path
ArCo: the Italian Cultural Heritage Knowledge Graph
ArCo is the Italian Cultural Heritage knowledge graph, consisting of a
network of seven vocabularies and 169 million triples about 820 thousand
cultural entities. It is distributed jointly with a SPARQL endpoint, a software
for converting catalogue records to RDF, and a rich suite of documentation
material (testing, evaluation, how-to, examples, etc.). ArCo is based on the
official General Catalogue of the Italian Ministry of Cultural Heritage and
Activities (MiBAC) - and its associated encoding regulations - which collects
and validates the catalogue records of (ideally) all Italian Cultural Heritage
properties (excluding libraries and archives), contributed by CH administrators
from all over Italy. We present its structure, design methods and tools, its
growing community, and delineate its importance, quality, and impact
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