Testing linear cointegration against smooth-transition cointegration

This paper studies a smooth-transition (ST) type cointegration. The proposed ST cointegration allows for regime switching structure in a cointegrated system. It nests the linear cointegration developed by Engle and Granger (1987) and the threshold cointegration studied by Balke and Fomby (1997). We develop F-type tests to examine linear cointegration against ST cointegration in ST-type cointegrating regression models with or without time trends. The null asymptotic distributions of the tests are derived with stationary transition variables in ST cointegrating regression models. And it is shown that our tests have nonstandard limiting distributions expressed in terms of standard Brownian motion when regressors are pure random walks, while have standard asymptotic distributions when regressors contain random walks with nonzero drift. Finite-sample distributions of those tests are studied by Monto Carlo simulations. The small-sample performance of the tests states that our F-type tests have a better power when the system contains ST cointegration than when the system is linearly cointegrated. An empirical example for the purchasing power parity (PPP) data (monthly US dollar, Italy lira and dollar-lira exchange rate from 1973:01 to 1989:10) is illustrated by applying the testing procedures in this paper. It is found that there is no linear cointegration in the system, but there exits the ST-type cointegration in the PPP data.

Healthcare providers balancing norms and practice : challenges and opportunities in providing contraceptive counselling to young people in Uganda - a qualitative study

BACKGROUND: Pregnancies among young women force girls to compromise education, resulting in low educational attainment with subsequent poverty and vulnerability. A pronounced focus is needed on contraceptive use, pregnancy, and unsafe abortion among young women. OBJECTIVE: This study aims to explore healthcare providers' (HCPs) perceptions and practices regarding contraceptive counselling to young people. DESIGN: We conducted 27 in-depth interviews with doctors and midwives working in seven health facilities in central Uganda. Interviews were open-ended and allowed the participant to speak freely on certain topics. We used a topic guide to cover areas topics of interest focusing on post-abortion care (PAC) but also covering contraceptive counselling. Transcripts were transcribed verbatim and data were analysed using thematic analysis. RESULTS: The main theme, HCPs' ambivalence to providing contraceptive counselling to sexually active young people is based on two sub-themes describing the challenges of contraceptive counselling: A) HCPs echo the societal norms regarding sexual practice among young people, while at the same time our findings B) highlights the opportunities resulting from providers pragmatic approach to contraceptive counselling to young women. Providers expressed a self-identified lack of skill, limited resources, and inadequate support from the health system to successfully provide appropriate services to young people. They felt frustrated with the consultations, especially when meeting young women seeking PAC. CONCLUSIONS: Despite existing policies for young people's sexual and reproductive health in Uganda, HCPs are not sufficiently equipped to provide adequate contraceptive counselling to young people. Instead, HCPs are left in between the negative influence of social norms and their pragmatic approach to address the needs of young people, especially those seeking PAC. We argue that a clear policy supported by a clear strategy with practical guidelines should be implemented alongside in-service training including value clarification and attitude transformation to equip providers to be able to better cater to young people seeking sexual and reproductive health advice.

On a uniform turnpike of the third kind in the Robinson-Solow-Srinivasan model

On using McKenzie’s taxonomy of optimal accumulation in the longrun, we report a “uniform turnpike” theorem of the third kind in a model original to Robinson, Solow and Srinivasan (RSS), and further studied by Stiglitz. Our results are presented in the undiscounted, discrete-time setting emphasized in the recent work of Khan-Mitra, and they rely on the importance of strictly concave felicity functions, or alternatively, on the value of a “marginal rate of transformation”, ξσ, from one period to the next not being unity. Our results, despite their specificity, contribute to the methodology of intertemporal optimization theory, as developed in economics by Ramsey, von Neumann and their followers.

A roughly smooth optimal consumption path: smoothing the rough annuity puzzle

A inconsistência entre a teoria e o comportamento empírico dos agentes no que tange ao mercado privado de pensões tem se mostrado um dos mais resistentes puzzles presentes na literatura econômica. Em modelos de otimização intertemporal de consumo e poupança sob incerteza em relação ao tempo de vida dos agentes, anuidades são ativos dominantes, anulando ou restringindo fortemente a demanda por ativos cujos retornos não estão relacionados à probabilidade de sobrevivência. Na prática, entretanto, consumidores são extremamente céticos em relação às anuidades. Em oposição ao seguro contra longevidade oferecido pelas anuidades, direitos sobre esses ativos - essencialmente ilíquidos - cessam no caso de morte do titular. Nesse sentido, choques não seguráveis de liquidez e a presença de bequest motives foram consideravelmente explorados como possíveis determinantes da baixa demanda verificada. Apesar dos esforços, o puzzle persiste. Este trabalho amplia a dominância teórica das anuidades sobre ativos não contingentes em mercados incompletos; total na ausência de bequest motives, e parcial, quando os agentes se preocupam com possíveis herdeiros. Em linha com a literatura, simulações numéricas atestam que uma parcela considerável do portfolio ótimo dos agentes seria constituída de anuidades mesmo diante de choques de liquidez, bequest motives, e preços não atuarialmente justos. Em relação a um aspecto relativamente negligenciado pela academia, mostramos que o tempo ótimo de conversão de poupança em anuidades está diretamente relacionado à curva salarial dos agentes. Finalmente, indicamos que, caso as preferências dos agentes sejam tais que o nível de consumo ótimo decaia com a idade, a demanda por anuidades torna-se bastante sensível ao sobrepreço (em relação àquele atuarialmente justo) praticado pela indústria, chegando a níveis bem mais compatíveis com a realidade empírica.

A tendência de flexibilização da imunidade de jurisdição frente a graves violações de direitos humanos

O enfoque do presente Trabalho de Conclusão de Curso repousa sobre tendência de flexibilização da Imunidade de Jurisdição Estatal em casos de graves violações a Direitos Humanos, tendo em vista o teor das decisões de cortes nacionais e internacionais. A problemática reside no fato de que, em algumas situações, a Imunidade de Jurisdição Estatal, norma utilizada para preservação da soberania estatal, contrapõe-se a direitos fundamentais do cidadão, sujeito de Direito Internacional Público. Nesse sentido, o presente trabalho traz à baila a discussão sobre a tendência de flexibilização dessas normas consoante a observância de normas imperativas relativas à proteção de graves violações de Direitos Humanos. A hipótese do presente trabalho consiste em averiguar a tendência de flexibilização da Imunidade de Jurisdição Estatal quando contraposta a graves violações de Direitos Humanos. Observar-se-á, para tanto, o comportamento das cortes nacionais e internacionais, amparados pelos ensinamentos jurídico-doutrinários a respeito da normatização dos direitos em conflito. O intuito dessa explanação consiste não só em um (i) argumento de hierarquia, o qual enseja o questionamento da supremacia jurídica das normas de jus cogens sobre as demais, não se limitando ao Direito dos Tratados, mas também a (ii) no argumento de que a própria imunidade de jurisdição que nasceu de um costume internacional, i.e., prática reiterada uniforme e constante, pode estar-se diante de nova tendência de flexibilização da norma porquanto o surgimento de novo costume internacional, qual seja, a proteção legítima de graves violações de Direitos Humanos.

Social norms and money

In an economy where there is no double coincidence of wants and without recordkeeping of past transactions, money is usually seen as the only mechanism that can support exchange. In this paper, we show that, as long as the population is finite and agents are sufficiently patient, a social norm establishing gift-exchange can substitute for money. Notwithstanding, for a given discount factor, the growth of the population size eventually leads to the breakdown of the social norm, while money still works. 1 Introduction

Tree-structured smooth transition models

The goal of this paper is to introduce a class of tree-structured models that combines aspects of regression trees and smooth transition regression models. The model is called the Smooth Transition Regression Tree (STR-Tree). The main idea relies on specifying a multiple-regime parametric model through a tree-growing procedure with smooth transitions among different regimes. Decisions about splits are entirely based on a sequence of Lagrange Multiplier (LM) tests of hypotheses.

AVALIAÇÃO DE PLANTAS MATRIZES DE ABACAXIZEIRO CULTIVAR SMOOTH CAYENNE UTILIZANDO MARCADORES RAPD E PADRÕES ISOENZIMÁTICOS

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

Avaliação por RAPD de plantas de abacaxizeiro cultivar Smooth Cayenne derivadas do seccionamento do talo e cultura de tecidos

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

A fully adaptive multiresolution scheme for shock computations

The scheme is based on Ami Harten's ideas (Harten, 1994), the main tools coming from wavelet theory, in the framework of multiresolution analysis for cell averages. But instead of evolving cell averages on the finest uniform level, we propose to evolve just the cell averages on the grid determined by the significant wavelet coefficients. Typically, there are few cells in each time step, big cells on smooth regions, and smaller ones close to irregularities of the solution. For the numerical flux, we use a simple uniform central finite difference scheme, adapted to the size of each cell. If any of the required neighboring cell averages is not present, it is interpolated from coarser scales. But we switch to ENO scheme in the finest part of the grids. To show the feasibility and efficiency of the method, it is applied to a system arising in polymer-flooding of an oil reservoir. In terms of CPU time and memory requirements, it outperforms Harten's multiresolution algorithm.The proposed method applies to systems of conservation laws in 1Dpartial derivative(t)u(x, t) + partial derivative(x)f(u(x, t)) = 0, u(x, t) is an element of R-m. (1)In the spirit of finite volume methods, we shall consider the explicit schemeupsilon(mu)(n+1) = upsilon(mu)(n) - Deltat/hmu ((f) over bar (mu) - (f) over bar (mu)-) = [Dupsilon(n)](mu), (2)where mu is a point of an irregular grid Gamma, mu(-) is the left neighbor of A in Gamma, upsilon(mu)(n) approximate to 1/mu-mu(-) integral(mu-)(mu) u(x, t(n))dx are approximated cell averages of the solution, (f) over bar (mu) = (f) over bar (mu)(upsilon(n)) are the numerical fluxes, and D is the numerical evolution operator of the scheme.According to the definition of (f) over bar (mu), several schemes of this type have been proposed and successfully applied (LeVeque, 1990). Godunov, Lax-Wendroff, and ENO are some of the popular names. Godunov scheme resolves well the shocks, but accuracy (of first order) is poor in smooth regions. Lax-Wendroff is of second order, but produces dangerous oscillations close to shocks. ENO schemes are good alternatives, with high order and without serious oscillations. But the price is high computational cost.Ami Harten proposed in (Harten, 1994) a simple strategy to save expensive ENO flux calculations. The basic tools come from multiresolution analysis for cell averages on uniform grids, and the principle is that wavelet coefficients can be used for the characterization of local smoothness.. Typically, only few wavelet coefficients are significant. At the finest level, they indicate discontinuity points, where ENO numerical fluxes are computed exactly. Elsewhere, cheaper fluxes can be safely used, or just interpolated from coarser scales. Different applications of this principle have been explored by several authors, see for example (G-Muller and Muller, 1998).Our scheme also uses Ami Harten's ideas. But instead of evolving the cell averages on the finest uniform level, we propose to evolve the cell averages on sparse grids associated with the significant wavelet coefficients. This means that the total number of cells is small, with big cells in smooth regions and smaller ones close to irregularities. This task requires improved new tools, which are described next.