8,174 research outputs found
The current status of dental education and the dental profession in Chile
Indexación: Scopus.Objective: To describe the current situation of the dental profession in Chile, including training and workforce issues. Material and Methods: Data were collected from different national institutions, which included information regarding number of current registered dentists, university of graduation, geographical distribution, professional position, additional specialty certifications obtained, the number and characteristics of dental surgeons who work in the public and private sectors, the traditional character of the university, the accreditation status of the undergraduate dental programs and the general population number. Results: Currently there are 32 schools of Dentistry in Chile, of which 21 have their quality certified. There are 19,100 Chilean dentists and 1,727 foreign dentists registered. The number of graduates from private universities has increased significantly. Currently, 2,164 dentists work for MINSAL. Less than a third hold a specialty certification. Forty-five percent of the dental specialists obtained their certification from universities. The current professional ratio is 104 dentists per 100,000 habitants. Conclusion: The number of dentists in Chile has increased progressively during the last years, mainly associated with the opening of new dental schools. Only 28% of the Chilean dental schools have certified their quality for the total duration of the undergraduate program. Regarding the workforce, there is a public/private and geographical inequities in dentists’ distribution.http://revista.uepb.edu.br/index.php/pboci/article/view/3875/pd
Exact infinite-time statistics of the Loschmidt echo for a quantum quench
The equilibration dynamics of a closed quantum system is encoded in the
long-time distribution function of generic observables. In this paper we
consider the Loschmidt echo generalized to finite temperature, and show that we
can obtain an exact expression for its long-time distribution for a closed
system described by a quantum XY chain following a sudden quench. In the
thermodynamic limit the logarithm of the Loschmidt echo becomes normally
distributed, whereas for small quenches in the opposite, quasi-critical regime,
the distribution function acquires a universal double-peaked form indicating
poor equilibration. These findings, obtained by a central limit theorem-type
result, extend to completely general models in the small-quench regime.Comment: 4 pages, 2 figure
The spin glass transition of the three dimensional Heisenberg spin glass
It is shown, by means of Monte Carlo simulation and Finite Size Scaling
analysis, that the Heisenberg spin glass undergoes a finite-temperature phase
transition in three dimensions. There is a single critical temperature, at
which both a spin glass and a chiral glass orderings develop. The Monte Carlo
algorithm, adapted from lattice gauge theory simulations, makes possible to
thermalize lattices of size L=32, larger than in any previous spin glass
simulation in three dimensions. High accuracy is reached thanks to the use of
the Marenostrum supercomputer. The large range of system sizes studied allow us
to consider scaling corrections.Comment: 4 pages, 4 Postscript figures, version to be published in Physical
Review Letter
The Assembly of the LHC Short Straight Sections at CERN: Work Organization, Quality Assurance and Lessons Learned
After 4 years of activity, the assembly of approximately 500 Short Straight Sections (SSS) for the LHC has come to an end at the beginning of 2007. This activity, which was initially foreseen in European industry, was in-sourced at CERN because of the insolvency of the prime contractor. While the quadrupole cold masses were produced in industry, the assembly within their cryostats was transferred to CERN and executed by an external company under a result-oriented contract. CERN procured cryostat components, set up a dedicated 2000 m2 assembly hall with all the specific assembly equipment and tooling and defined the assembly and testing procedures. The contractor took up responsibility for the delivery, on time, of assemblies according to the required quality. A dedicated CERN production and quality assurance team was constituted. A specific quality assurance plan was set up involving 2 additional contractors responsible for weld inspections on a total of about 20'000 assembly welds and the execution of about 3300 leak detection tests. This paper presents the organizational aspects of the activity and the experience gained throughout the production. The learning curves and statistics by type of non-conformities detected and general quality assurance aspects are presented and discussed. The main lessons learnt are summarized, in an attempt to draw some conclusions which could be useful in making strategic choices for the cryostat assembly in future large-scale accelerators
New properties of scalar field dynamics in brane isotropic cosmological models
Several aspects of scalar field dynamics on a brane which differs from
corresponding regimes in the standard cosmology are investigated. We consider
asymptotic solution near a singularity, condition for inflation and bounces and
some detail of chaotic behavior in the brane model. Each results are compared
with those known in the standard cosmology.Comment: 13 pages with 2 eps figures, submitted to Astronomy Letter
Gestion du grand gibier dans les systèmes agroforestiers méditerranéens du sud-ouest de l'Espagne.
2011-06-14T13:09:33
Leak-Tight Welding Experience from the Industrial Assembly of the LHC Cryostats at CERN
The assembly of the approximately 1700 LHC main ring cryostats at CERN involved extensive welding of cryogenic lines and vacuum vessels. More than 6 km of welding requiring leak tightness to a rate better than 1.10-9Â mbar.l.s-1 on stainless steel and aluminium piping and envelopes was made, essentially by manual welding but also making use of orbital welding machines. In order to fulfil the safety regulations related to pressure vessels and to comply with the leak-tightness requirements of the vacuum systems of the machine, welds were executed according to high qualification standards and following a severe quality assurance plan. Leak detection by He mass spectrometry was extensively used. Neon leak detection was used successfully to locate leaks in the presence of helium backgrounds. This paper presents the quality assurance strategy adopted for welds and leak detection. It presents the statistics of non-conformities on welds and leaks detected throughout the entire production and the advances in the use of alternative leak detection methods in an industrial environment
Historic Appraisal Review and Geometric Characterization of Old Masonry Buildings in Lisbon for Seismic Risk Assessment
The Metropolitan Area of Lisbon (MAL) has the highest population and building density in Portugal, and is exposed to medium to high magnitude earthquakes due to its geographical location. Currently, the MAL housing stock is constituted by approximately 35% of masonry residential buildings with a large variability of materials and construction techniques, as a result of many centuries of history. Most of these buildings were built before the introduction of the first design code for building safety against earthquakes (RSSCS) in Citation1958 and therefore were only designed to support gravity loads. Given the presence of these buildings in areas of significant seismicity, a comprehensive research is needed to assess the seismic risk and define mitigation policies for this population of unreinforced masonry buildings. The main purpose of this work is thus to geometrically characterize these typologies, through an exhaustive survey of dozens of masonry buildings collected from original drawings and identify the most important aspects that can influence their seismic behavior. After a compressive historical background, the information collected is statistically analyzed and expressed through probability distributions that can be used for the development of numerical models and derive seismic vulnerability functions, fundamental to conduct seismic risk analyses.info:eu-repo/semantics/publishedVersio
Avaliação de cultivares de Coffea arabica L. ao parasitismo de Meloidogyne exigua.
Os nematóides podem causar grandes danos em cafezais no Brasil, dependendo da espécie e do tipo de solo. A espécie Meloidogyne exigua é a mais disseminada nas regiões cafeeiras, especialmente em lavouras mais velhas do Sul de Minas Gerais. As áreas com nematóides mostram redução tanto no desenvolvimento das plantas como na produção. Dentre as medidas de controle do nematóide, a que tem-se mostrado mais adequada é o uso de cultivares resistentes. O objetivo deste ensaio foi avaliar o comportamento de diferentes cultivares de Coffea arabica L. quando inoculados com M. exigua, visando a identificação de fontes de resistência. O ensaio foi instalado no setor de Nematologia da UFLA /Lavras-MG, em casa de vegetação, sob delineamento experimental de blocos ao acaso, com quatro repetições e três plantas por parcela. Foram avaliadas 22 cultivares, utilizando-se a cultivar Acaiá 474/19 e IAPAR 59, como padrões de suscetibilidade e de resistência, respsctivamente. Cada planta foi inoculada 80 dias após transplantio com 5000 ovos de M. exigua e avaliadas 40 e 120 dias após inoculação quanto ao número de galhas por grama de raiz. A cultivar IAPAR 59 confirmou ser imune, já que nenhuma galha foi observada em seu sistema radicular. As cultivares Catucaí Vermelho 785/15 e Acauã apresentaram segregação sendo algumas plantas resistentes e outras de reduzida susceptibilidade. As cultivares Catucaí Vermelho 36/6, Siriema, Soledade, Bem-te-vi Amarelo, Catucaí Vermelho 20/15- cv 395, Catucaí Amarelo 3-5, Cultivar oriunda de Franca, Catucaí Vermelho 36/6- cv 470, Catucaí Amarelo 24/137, Sabiá Tardio, Catucaí Amarelo 2SL- cv 446, Catucaí Amarelo 3 SM, Catucaí Amarelo 20/15- 479, Icatu IAC 2944, IBC-Palma II, Canário, Catucaí Açu Vermelho, IBC-Palma I e Acaiá-IAC 474/19 foram classificadas como susceptíveis, embora tivessem apresentado na primeira avaliação baixos índices de infestação, quando comparadas a cultivar Acaiá-IAC 474/19, o que indica a possibilidade de diferentes níveis de susceptibilidade entre as mesmas
Determining R-parity violating parameters from neutrino and LHC data
In supersymmetric models neutrino data can be explained by R-parity violating
operators which violate lepton number by one unit. The so called bilinear model
can account for the observed neutrino data and predicts at the same time
several decay properties of the lightest supersymmetric particle. In this paper
we discuss the expected precision to determine these parameters by combining
neutrino and LHC data and discuss the most important observables. We show that
one can expect a rather accurate determination of the underlying R-parity
parameters assuming mSUGRA relations between the R-parity conserving ones and
discuss briefly also the general MSSM as well as the expected accuracies in
case of a prospective e+ e- linear collider. An important observation is that
several parameters can only be determined up to relative signs or more
generally relative phases.Comment: 13 pages, 13 figure
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