3,462 research outputs found
INSTITUTIONAL CHANGE AND ECONOMIC TRANSFORMATION IN BRAZIL, 1945-2004 - FROM INDUSTRIAL CATCHING-UP TO FINANCIAL FRAGILITY
This paper tries to explain the dynamics of Brazilian industrial catch-up in the last 60 years by discussing its background institutional conditions as well as its main macroeconomic features. After a brief introduction, the second section describes how after the institutional innovations introduced during the Vargas's and Kubitschek's administrations, a Brazilian version of the Developmental State was created, releasing the growth potential of the economy during the 1950s. The third section analyses the inflationary crisis and institutional inertia of the mid-1960s, and its solution through the introduction of a new of wave of institutional innovations and conflict management devices, which lead to the Brazilian growth miracle, until the debt crisis of early 1980s signaled its end. The fourth section analyses why the financial crisis, coupled with ineffective institutional changes and unsuccessful macroeconomic stabilization plans lead growth to a halt. It also includes an analysis of the pro-market reforms from the early 1990s onwards. The fifth section concludes the paper offering a brief sketch on how the analytical narrative fits the conceptual framework within which it was carried.
The dependence of the viscosity-parameter on the disk scale height profile
It is shown that the height scale for accretion disks is a constant whenever
hydrostatic equilibrium and sub-sonic turbulence regime hold in the disk. In
order to have a variable height scale, processes that do contribute with an
extra term to the continuity equation are needed. This makes the viscosity
parameter much greater in the outer region and much smaller in the inner
region. Under these circumstances, turbulence is a presumable source of
viscosity in the disk.Comment: 8 pages, submitted to Apj
Paracoccidioidomicose em crianças, com comprometimento ósseo distinto
The rarity of paracoccidioidomycosis in childhood prompted us to report two cases with different clinical and radiological skeletal involvement. The number of osteolytic lesions, the presence of periosteal reaction and the finding of Paracoccidioides brasiliensis in biopsy specimens, were distinctive features in both cases.São apresentados dois casos de paracoccidioidomicose óssea, cujas diferenças eram em relação ao número das lesões, ao aspecto radiológico e à presença do fungo em biópsia das lesões. O relato se deve à raridade desta doença em crianças
A simple mathematical model underlying Keller's individualized teaching method
Keller's article entitled ``Good-bye teacher...'' [J. Appl. Behav. Anal.
\textbf{1}, 79-89 (1968)] was fundamental for the development and dissemination
of Keller's Personalized System of Instruction (PSI), which was one of the
central issues in the discussions on psychology and education in the 1970s and
1980s, and nowadays has attracted attention in the context of the increasing
use of online education. Belonging to a class of approaches usually named as
mastery learning, PSI and modified PSI courses (Keller-type courses) present
several interesting results, such as final grade distributions where the
majority of students achieve the highest grades. Here, we present a simple
mathematical model underlying Keller-type individualized teaching methods,
describing, in terms of average characteristic parameters, the time evolution
of the distribution of students per unit of content, and that most students
achieve the highest grades at the end of the course. By applying this model to
a real case of an introductory electromagnetism Keller-type course, we obtained
its characteristic parameters with which we showed good agreement between the
predictions and observations. The model presented here results in a simple
formula, which is very accessible for use by a wide audience interested in
planning or investigating Keller-type or other mastering learning methods.Comment: 15 pages, 5 figure
Glueball Regge trajectories from gauge/string duality and the Pomeron
The spectrum of light baryons and mesons has been reproduced recently by
Brodsky and Teramond from a holographic dual to QCD inspired in the AdS/CFT
correspondence. They associate fluctuations about the AdS geometry with four
dimensional angular momenta of the dual QCD states. We use a similar approach
to estimate masses of glueball states with different spins and their
excitations. We consider Dirichlet and Neumann boundary conditions and find
approximate linear Regge trajectories for these glueballs. In particular the
Neumann case is consistent with the Pomeron trajectory.Comment: In this revised version we made some additional remarks on the text.
We also included 2 more references. The glueball spectrum and Regge
trajectories are unchanged. 10 pages, 2 eps figure
Anti-de Sitter boundary in Poincare coordinates
We study the space-time boundary of a Poincare patch of Anti-de Sitter (AdS)
space. We map the Poincare AdS boundary to the global coordinate chart and show
why this boundary is not equivalent to the global AdS boundary. The Poincare
AdS boundary is shown to contain points of the bulk of the entire AdS space.
The Euclidean AdS space is also discussed. In this case one can define a
semi-global chart that divides the AdS space in the same way as the
corresponding Euclidean Poincare chart.Comment: In this revised version we add a discussion of the physical
consequences of the choice of a coordinate system for AdS space. We changed
figure 1 and added more references. Version to be published in Gen. Relat.
Grav
Black-hole quasinormal modes and scalar glueballs in a finite-temperature AdS/QCD model
We use the holographic AdS/QCD soft-wall model to investigate the spectrum of
scalar glueballs in a finite temperature plasma. In this model, glueballs are
described by a massless scalar field in an AdS_5 black hole with a dilaton
soft-wall background. Using AdS/CFT prescriptions, we compute the boundary
retarded Green's function. The corresponding thermal spectral function shows
quasiparticle peaks at low temperatures. We also compute the quasinormal modes
of the scalar field in the soft-wall black hole geometry. The temperature and
momentum dependences of these modes are analyzed. The positions and widths of
the peaks of the spectral function are related to the frequencies of the
quasinormal modes. Our numerical results are found employing the power series
method and the computation of Breit-Wigner resonances.Comment: Revision: Results unchanged. More discussions on the model and on the
results. References added. 28 pages, 7 figures, 5 table
Study of poly(o-Ethoxyaniline) interactions with herbicides and evaluation of conductive polymer potential used in electrochemical sensors
Interactions of four aromatic nitrogen-heterocyclic herbicides (atrazine, imazaquin, metribuzin and paraquat) with the conductive polymer poly(o-ethoxyaniline)-POEA, were studied with atomic force microscopy (AFM), UV-visible spectrophotometry (UV-Vis) and electrochemical impedance spectroscopy. AFM profiles of self-assembled (SA) films of POEA revealed that the polymer surface became rougher (on the nanoscale) when exposed to atrazine, imazaquin and metribuzin, but slightly smoother in contact with paraquat. This suggested that specific chemical interactions, possibly electroscopic, have occurred between nitrogen atoms in the polymer chain and the dissimilar groups in the various herbicide molecules, during adsorption of the latter onto the film. The UV-Vis analyses indicated a stronger interaction of POEA in solution with imazaquin, that has a special importance for the intended application. Sensors produced by coating microelectrodes with SA films of POEA were used to perform impedance spectroscopy in aqueous solutions of each herbicide. With the resulting data, it was possible to distinguish and set detection limits for each herbicide in water, corroborating AFM and UV-Vis results
f-Oscillators and Nonlinear Coherent States
The notion of f-oscillators generalizing q-oscillators is introduced. For
classical and quantum cases, an interpretation of the f-oscillator is provided
as corresponding to a special nonlinearity of vibration for which the frequency
of oscillation depends on the energy. The f-coherent states (nonlinear coherent
states) generalizing q-coherent states are constructed. Applied to quantum
optics, photon distribution function, photon number means, and dispersions are
calculated for the f-coherent states as well as the Wigner function and
Q-function. As an example, it is shown how this nonlinearity may affect the
Planck distribution formula.Comment: Latex, 32 pages, accepted by Physica Script
The microbial culture collections of the Federal University of Pernambuco (UFPE) and the new consortium towards the establishment of BRC-UFPE
The UFPE from Recife in Brazil hosts a bacterial (UFPEDA) and a fungal (URM) collections since 1951 and 1954, respectively. The UFPEDA was established by Prof. Oswaldo Gonçalves de Lima and is register in WDCM as 114. It is hosted at Antibiotic Department (DA) of UFPE and started out with 200 species mainly of the genus Streptomyces. Nowadays this collection holds 4000 strains of actinomycetes isolated from all the Brazilian places and from the International Streptomyces Project (ISP). The URM – University of Recife Mycology was established by Prof. Augusto Chaves Batista and is register in WDCM as 604. Actual it holds 9000 identified species including 1400 yeasts and 7600 filamentous fungi. All major fungal taxonomic groups are cover by this collection. The collections preserve each strain at least by two different techniques. Water and mineral oil storage were used for long operation time while freeze-drying and freezing at -80 ºC become the main techniques used at this stage. Special care is taken to test whether cultures recovered from preserved material conform to the original deposit. These collections have a range of services which are acceptance of free and confidential deposits, supply strains for academia, industry and services, support research and education (graduate and post-graduate students, as well as advanced training courses), identification services and confidential contracts (e.g. fungal medical diagnosis, starters for agro-industry companies, etc.). The OECD initiative related to guidance for the operation of Biological Resource Centres (BRC) is now a key reference for these collections. The right management of biological resources and their associate information including quality control are perused by these collections. The recent national projects, with reasonable budgets to support their activities, either on networking activities or requalification and management create a new breath and responsibilities to these collections. Taking advantage of good and well equipped premises of LIKA these collections are now open new avenues working in consortium to improve the quality control of their holdings using new tools from molecular biology and spectral analysis (MALDI-TOF) to achieve in the future a certified BRC for the UFPE microbial culture collections
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