Dynamics of micro-entrepeneurial activities

This paper generates and organizes stylized facts related to the dynamics of selfemployment activities in Brazil. The final purpose is to help the design of policies to assist micro-entrepreneurial units. The 'first part of the paper uses as a main tool of analysis transitional data constructed from household surveys. The longitudinal information used covers three transition horizons: 1-month, 12-month and 5-year periods. Quantitative flows analysis assesses the main origins, destinies and various types of risks assumed by microentrepreneurial activities. Complementarily, logistic regressions provides evidence on the main characteristics and resources of micro-entrepreneurial units. In particular, we use the movements from self-employment to employer activities as measures of entrepreneurial success. We also use these transitions as measures of employment creation intensity within the self-employed segment.The second part of the paper explores various data sources. First, we attempt to analyze the life-cycle trajectories and determinants of self-employment. We use cohort data constructed from PME and qualitative data on financial and work history factors related to the opening of small bussiness from the informal firms survey implemented during 1994. Second, we apply a standart Mincerian wage equation approach to self-employment profits. This exerci se attempts to capture the correlation patterns between micro-entrepreneurial performance and a variety of firms leveI variables present in the 1994 Informal Survey. Finally, we use a a survey on the poor enterpreneurs of Rocinha favela as a laboratory to study poor entrepreneurs resources and behavior.In sum, the main questions pursued in the paper are: i) who are the Brazilian selfemployed?; ii) in particular: what is relative importance among the self-employed of subsistence activities versus those activities with growth and capital accumulation potential?; iii) what are the main static and dynamic determinants ofmicro-entrepreneurial success?; iv) what is the degree ofrisk associated with micro-entrepreneurial activities in Brazil?; v) What is the life-cycle profile of self-employment?; vi) what are the main constraints on poor entrepreneurs activities?.

Welfare characterization of monetary-applied models and three implications

This paper demonstrates that the applied monetary mo deIs - the Sidrauski-type models and the cash-in-advance models, augmented with a banking sector that supplies money substitutes services - imply trajectories which are P8,reto-Optimum restricted to a given path of the real quantity of money. As a consequence, three results follow: First, Bailey's formula to evaluate the wclfare cost of inflation is indeed accurate, if the long-run capital stock does not depend on the inflation rate and if the compensate demand is considered. Second, the relevant money demand concept for this issue - the impact of inflation on welfare - is the monetary base, Third, if the long-run capital stock depends on the inflation rate, this dependence has a second-order impact ou wclfare, and, conceptually, it is not a distortion from tite social point of vicw. These three implications moderatc some evaluations of the wclfare cost of the perfect predicted inflation.

Windows of opportunities and knowledge networks: implications for the catch-up in developing countries

This document represents a doctoral thesis held under the Brazilian School of Public and Business Administration of Getulio Vargas Foundation (EBAPE/FGV), developed through the elaboration of three articles. The research that resulted in the articles is within the scope of the project entitled “Windows of opportunities and knowledge networks: implications for catch-up in developing countries”, funded by Support Programme for Research and Academic Production of Faculty (ProPesquisa) of Brazilian School of Public and Business Administration (EBAPE) of Getulio Vargas Foundation.

Irregular satellites of Jupiter: capture configurations of binary-asteroids

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

5S rDNA chromosomal mapping and COI sequence analysis reveal differentiation among distinct populations of a characid fish Serrapinnus notomelas

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

de Sitter geodesics: reappraising the notion of motion

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effects of oscillatory behavior of the dipole function on the dissociation dynamics of the classical driven Morse oscillator

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of robust torus on the dynamical transport

In the present work, we quantify the fraction of trajectories that reach a specific region of the phase space when we vary a control parameter using two symplectic maps: one non-twist and another one twist. The two maps were studied with and without a robust torus. We compare the obtained patterns and we identify the effect of the robust torus on the dynamical transport. We show that the effect of meandering-like barriers loses importance in blocking the radial transport when the robust torus is present.

Possibility of collision between co-orbital asteroids and the Earth

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Alternative paths for insertion of probes into high inclination lunar orbits

The dynamics of the restricted three-body Earth-Moon-particle problem predicts the existence of direct periodic orbits around the Lagrangian equilibrium point L1. From these orbits, we derive a set of trajectories that form links between the Earth and the Moon and are capable of performing transfers between terrestrial and lunar orbits, in addition to defining an escape route from the Earth-Moon system. When we consider a more complex and realistic dynamical system - the four-body Sun-Earth-Moon-particle (probe) problem - the trajectories have an expressive gain of inclination when they penetrate in the lunar influence sphere, thus allowing the insertion of probes into low-altitude lunar orbits with high inclinations, including polar orbits. In this study, we present these links and investigate some possibilities for performing an Earth-Moon transfer based on these trajectories. (C) 2007 COSPAR. Published by Elsevier Ltd. All rights reserved.

Metamorphic evolution of a subduction complex, South Shetland Islands, Antarctica

A subduction complex composed of ocean floor material mixed with arc-derived metasediments crops out in the Elephant Island group and at Smith Island, South Shetland Islands, Antarctica, with metamorphic ages of 120-80 Ma and 58-47 Ma? respectively. Seven metamorphic zones (I-VII) mapped on Elephant Island delineate a gradual increase in metamorphic grade from the pumpellyite-actinolite facies, through the crossite-epidote blueschist facies, to the lower amphibolite facies. Geothermometry in garnet-amphibole and garnet-biotite pairs yields temperatures of about 350 degrees C in zone III to about 525 degrees C in zone VII. Pressures were estimated on the basis of Si content in white mica, Al2O3 content in alkali amphibole, Na-M4/Al-IV in sodic-calcic and calcic amphibole, Al-VI/Si in calcic amphibole, and jadeite content in clinopyroxene. Mean values vary from about 6-7.5 kbar in zone II to about 5 kbar in zone VII. Results from the other islands of the Elephant Island group are comparable to those from the main island; Smith Island yielded slightly higher pressures, up to 8 kbar, with temperatures estimated between 300 and 350 degrees C. Zoned minerals and other textural indications locally enable inference of P-T-t trajectories, all with a clockwise evolution. A reconstruction in space and time of these P-T-t paths allows an estimate of the thermal structure in the upper crust during the two ductile deformation phases (D-1 & D-2) that affected the area. This thermal structure is in good agreement with the one expected for a subduction zone. The arrival and collision of thickened oceanic crust may have caused the accretion and preservation of the subduction complex. In this model, D-1 represents the subduction movements expressed by the first vector of the clockwise P-T-t path, D-2 reflects the collision corresponding to the second vector with increasing temperature and decreasing pressure, and D-3 corresponds to isostatic uplift accompanied by erosion, under circumstances of decreasing temperature and pressure.

The end magnets of the IFUSP race-track microtron booster

The end magnets of the IFUSP race-track microtron booster, second stage of the electron accelerator under construction at the Linear Accelerator Laboratory, are presented. They deflect, focus and return the beam to the accelerating section. Details about the project are discussed, Poisson code was used to give the final geometry of the end magnets. The end magnets incorporate auxiliary pole pieces (clamps) which create a reverse fringe field region that avoids the beam vertical defocusing and reduces the horizontal displacement produced by extended fringe fields (EFF). The small gap height used for the clamps provided reverse field distributions with fringe fields of short extensions, avoiding the traditional use of inactive clamps. Measurements and calculations concerning particle trajectories and reverse field distribution are presented. The floating wire technique, employing an original procedure to register orbits, was used to corroborate the calculated beam trajectories and represents a good experimental option in the lack of the accelerator beam. The experimental results showed agreement of about 0.1% with the calculations.

Prevalence of different types of accessory canals in the furcation area of third molars

Background: Although there are several studies that show the prevalence and diameter of accessory root canals in the furcation area, there is a scarceness of studies that observe the trajectory and different types of cavo-interradicular canals. The aim of this study was to verify the prevalence of the different morphologic types of accessory canals in the furcation region in an attempt to show their trajectories.Methods: Forty submerged mandibular third molars were used, which were extracted and decalcified so that the microtomy procedure in the mesio-distal axial plane could be performed, obtaining semiserial sections with thicknesses of 5 mu m. The sections were stained with hematoxylin and eosin and observed under optical microscopy.Results: All of the morphologic types were found, whereas the proper accessory canals, type-A canals, were present in 10% of the specimens. The most prevalent canals were the sealed ones (type D), with a prevalence of 87.5%, followed by the blind ones (type B), with a prevalence of 75%. The loop accessory canals (type C), observed in only 5% of the teeth, were the least prevalent ones.Conclusions: Different morphologic types of accessory canals were found in the furcation area of submerged mandibular molars. The histologic method was effective to show the canal trajectories.

Simple generalization of Wisdom's perturbative method

A simple generalization of Wisdom's perturbative method, as originally proposed by Wisdom (1985), is obtained. Any number of resonant cosines can be handled and the method can also accommodate more involved disturbing functions. Averaged trajectories are easily obtained by drawing level curves of the action. Here, the method is first tested for simple models of 3:1 and 2:1 resonant problems. Comparisons with numerical integration and surface-section curves show very good agreements.

Effects of the eccentricity on the primaries in the gravitational capture phenomenon

Gravitational capture is a characteristic of some dynamical systems in celestial mechanics, as in the elliptic restricted three-body problem that is considered in this paper. The basic idea is that a spacecraft (or any particle with negligible mass) can change a hyperbolic orbit with a small positive energy around a celestial body into an elliptic orbit with a small negative energy without the use of any propulsive system. The force responsible for this modification in the orbit of the spacecraft is the gravitational force of the third body involved in the dynamics. In this way, this force is used as a zero cost control, equivalent to a continuous thrust applied in the spacecraft. One of the most important applications of this property is the construction of trajectories to the Moon. The objective of the present paper is to study in some detail the effects of the eccentricity of the primaries in this maneuver.