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?.

Wealth composition, endogenous fertility and the dynamics of income inequality

This paper analyzes how differences in the composition of wealth between human and physical capital among families affect fertility choices. These in tum influence the dynamics of wealth and income inequality across generations through a tradeoffbetween quantity and quality of children. Wealth composition affects fertility because physical capital has only a wealth effect on number of children, whereas human capital increases the time cost of child-rearing in addition to the wealth effect. I construct a model combining endogenous fertility with borrowing constraints in human capital investments, in which weaIth composition is determined endogenously. The model is calibrated to the PNAD, a Brazilian household survey, and the main findings of the paper can be summarized as follows. First, the model implies that the crosssection relationship between fertility and wealth typically displays a U-shaped pattem, reflecting differences in wealth composition between poor and rich families. Also, the quantity-quality tradeoff implies a concave cross-section relationship between investments per child and wealth. Second, as the economy develops and families overcome their bOlTowing constraints, the negative effect of weaIth on fertility becomes smaller, and persistence of inequality declines accordingly. The empirical evidence presented in this paper is consistent with both implications .

Dynamics of some limnological characteristics in pacu (Piaractus mesopotamicus) culture tanks as function of handling

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

Reproductive migration and population dynamics of the blue crab Callinectes danae in an estuary in southeastern Brazil

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

Effects of corn particle size and physical form of the diet on the gastrointestinal structures of broiler chickens

The objective of this experiment was to investigate the effects of different particle sizes, expressed as Geometric Mean Diameter (GMD) of corn (0.336mm, 0.585mm, 0.856mm and 1.12mm) of mash and pelleted broiler chicken diets on the weight of the gizzard, duodenum and jejunum+ileum; on the pH of the gizzard and small intestine and on the characteristics of the duodenal mucous layer (number and height of villi and crypt depth) in 42-day-old broilers. The physical form and the particle size of the diet had no significant effect on gizzard and intestine pH (p > 0.05). A greater gizzard weight was seen in the birds receiving pelleted diet and particle size of 0.336mm (p < 0.008). However, for the particle sizes of 0.856 and 1.12 mm, a greater weight was found in birds that received mash diet (p < 0.039 and p < 0.006, respectively). Also, gizzard weight was greater with increasing corn GMD independent of the physical form of the diet. In the mash diet, the increase in particle size promoted a quadratic response in the weight of duodenum and jejunum + ileum. The pelleted diet promoted a greater number of villi per transverse duodenum cut (p < 0.007) and greater crypt depth (p < 0.05). As the particle size increased, there was a linear increase of villus height and crypt depth in the duodenum, irrespective of the physical form of the diet.

The succession dynamics of a macroalgal community after a flood disturbance in a tropical stream from São Paulo State, southeastern Brazil

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

Ultrafast dynamics of bis (n-butylimido) perylene thin films excited by two-photon absorption

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

Global dynamics of the Rikitake system

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

GLOBAL DYNAMICS of THE LORENZ SYSTEM WITH INVARIANT ALGEBRAIC SURFACES

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

On the global dynamics of the Rabinovich system

In this paper by using the Poincare compactification in R(3) make a global analysis of the Rabinovich system(x) over dot = hy - v(1)x + yz, (y) over dot = hx - v(2)y - xz, (z) over dot = -v(3)z + xy,with (x, y, z) is an element of R(3) and ( h, v(1), v(2), v(3)) is an element of R(4). We give the complete description of its dynamics on the sphere at infinity. For ten sets of the parameter values the system has either first integrals or invariants. For these ten sets we provide the global phase portrait of the Rabinovich system in the Poincare ball (i.e. in the compactification of R(3) with the sphere S(2) of the infinity). We prove that for convenient values of the parameters the system has two families of singularly degenerate heteroclinic cycles. Then changing slightly the parameters we numerically found a four wings butterfly shaped strange attractor.