On learnability of E–stable equilibria

While under recursive least squares learning the dynamics of the economy converges to rational expectations equilibria (REE) which are E–stable, some recent examples propose that E–stability is not a sufficient condition for learnability. In this paper, we provide some further evidence on the conditions under which E–stability of a particular equilibrium might fail to imply its stochastic gradient (SG) or generalized SG learnability. We also claim that the requirement on the speed of convergence of the learning process imposed by [4] also implies that E–stable equilibria are likely to be GSG learnable. We show this in a simple â€New Keneysian†model of optimal monetary policy design in which the stability of REE under SG learning. In this case, the paper gives the conditions which are necessary for reversal of learnabilityAdaptive learning, E–stability, stochastic gradient, learnability

Learning Hyperinflations

Emprical studies of hyperinflations reveal that the rational expectations hypothesis fails to hold. To address this issue, we study a model of hyperinflation and learning in an attempt to better understand the volatility in movements of expectations, money, and prices. The findings surprisingly imply that the dynamics under neural network learning appear to support the outcome achieved under least squares learning reported in the earlier literature. Relaxing the assumption that inflationary expectations are rational, however, is essential since it improves the fit of the model to actual data from episodes of severe hyperinflation. Simulations provide ample evidence that if equilibrium in the model exists, then the inflation rate converges to the low inflation rational expectations equilibrium. This suggests a classical result: a permanent increase in the government deficit raises the stationary inflation rate (Marcet and Sargent, 1989)

Learning Hyperinflations

Emprical studies of hyperinflations reveal that the rational expectations hypothesis fails to hold. To address this issue, we study a model of hyperinflation and learning in an attempt to better understand the volatility in movements of expectations, money, and prices. The findings surprisingly imply that the dynamics under neural network learning appear to support the outcome achieved under least squares learning reported in the earlier literature. Relaxing the assumption that inflationary expectations are rational, however, is essential since it improves the fit of the model to actual data from episodes of severe hyperinflation. Simulations provide ample evidence that if equilibrium in the model exists, then the inflation rate converges to the low inflation rational expectations equilibrium. This suggests a classical result: a permanent increase in the government deficit raises the stationary inflation rate (Marcet and Sargent, 1989)Hyperinflation, Learning, Rational Expectations Equlibria, Neural Networks

Trade liberalization and employment effects in Ukraine

This paper addresses the important issue of the effects of trade liberalization on labor market job flows. It studies the case of Ukraine where we view the sudden openness of the economy to trade as a quasi-natural experiment. We use disaggregated data on manufacturing industries and customs data on trade flows taking account of shifting trade patterns after the disintegration of CMEA trade regime. We provide some first evidence that 3-digit NACE sector job flows are predominantly driven by idiosyncratic factors within industries. Other things equal, there is increased labor shedding as larger non-state share in industry relates to less job creation and more job destruction. Trade openness does affect job flows in Ukrainian manufacturing disproportionately according to trade orientation. We find that while trade with CIS decreases job destruction, trade with the EU increases excess reallocation mainly through job creation

ПРОУЧВАНЕ ВЛИЯНИЕТО НА СУХ ЕКСТРАКТ ОТ TRIBULUS TERRESTRIS ВЪРХУ ОСНОВНИ БИОХИМИЧНИ И ХЕМАТОЛОГИЧНИ ПОКАЗАТЕЛИ НА КРЪВТА ПРИ ТОКАЧКИ (NUMIDA MELEAGRIS)

The aim of the present research was to investigate the effect of Bulgarian additive Vemoherb-T (dry extract of the annual plant Tribulus terrestris – L), produced by Vemo 99 Ltd Company, Sofia on main biochemical characteristics and hematological parameters of the blood in guinea fowl (Numida meleagris). An experiment was carried out with 30 Pearl-gray Guinea fowl (32 weeks old), distributed in two groups – a control and an experimental, 12 female and 3 male each. All birds were fed the same mixture for breeder guinea fowl. Vemoherb-T was supplemented to the compound feed of the experimental group in a daily dose of 10 mg/kg body weight for a period of 12 weeks. The tested product decreased significantly the levels of total triglycerides (P < 0.05), total cholesterol (P <0.01) and glucose (P < 0.01; P < 0.001 in male and female birds respectively) in the blood serum. It was established significantly higher total protein- ((P < 0.001) and calcium (P<0.01) values in the blood serum of the treated birds. The addition of Vemoherb-T increased significantly hemoglobin level, the number of erythrocytes and leukocytes and decreased the number of eosinophils in guinea fowl from the both sexes.Целта на настоящото изследване беше да се установи влиянието на Българския продукт Vemoherb-T (сух екстракт от едногодишното растение Tribulus terrestris-L), произведен от фирма Вемо 99 ООД, София, върху основни биохимични характеристики и хематологични показатели на кръвен серум при токачки (Numida meleagris). Беше проведен научен експеримент с 30 Бисерносиви токачки (на 32 седмична възраст), разпределени в две групи – опитна и контролна, 12 женски и 3 мъжки всяка. Всички птици получаваха една и съща смеска за разплодни токачки. Vemoherb-T беше добавян към комбинирания фураж на опитната група ежедневно в доза 10 mg/kg жива маса в продължение на 12 седмици. Изпитваният продукт понижава достоверно нивата на общите триглицериди (P < 0.05), общия холестерол (P <0.01) и глюкозата (P < 0.01; P < 0.001 съответно за мъжките и женски птици) в кръвния серум. Бяха установени достоверно по- високи стойности на общия протеин ((P < 0.001) и на калция (P < 0.01) в кръвния серум на третираните птици. Добавката на Vemoherb-T повишава достоверно нивото на хемоглобина, броя на еритроцитите и лeвкоцитите, и понижава броя на еозинофилните левкоцити при токачките и от двата пола

The Hyperinflation Model of Money Demand (or Cagan Revisited): Some New Empirical Evidence from the 1990s

This paper employs cointegration techniques to examine three recent hyperinflationary episodes in transition economies, which, with the exception of Russia (1992-1994), have been largely overlooked in the literature. More specifically, these episodes include Bulgaria during 1995-1997 and Ukraine during 1993-1995. We use the well-known maximum likelihood estimator due to Johansen (1988, 1991) and Stock and Watson's (1993) dynamic ordinary least squares (DOLS) estimator to complement each other and obtain consistent estimates of the semi-elasticity of real money demand with respect to inflation. The empirical results obtained in this study support the Cagan model of money demand in the East European hyperinflation experiences of the 1990s. However, our results do not indicate that the rational expectations hypothesis holds during these episodes. In addition, we also test the hypothesis that monetary policy in these three hyperinflations was conducted with the sole intent of maximizing the inflation tax revenue for the government.Cagan, cointegration, inflation tax, transition economies, stabilizations