Free radicals in alcoholic myopathy: Indices of damage and preventive studies

Chronic alcoholic myopathy affects up to two-thirds of all alcohol misusers and is characterized by selective atrophy of Type If (glycolytic, fast-twitch, anaerobic) fibers. In contrast, the Type I fibers (oxidative, slow-twitch, aerobic) are relatively protected. Alcohol increases the concentration of cholesterol hydroperoxides and malondialdehyde-protein adducts, though protein-carbonyl concentration levels do not appear to be overtly increased and may actually decrease in some studies. In alcoholics, plasma concentrations of a-tocopherol may be reduced in myopathic patients. However, a-tocopherol supplementation has failed to prevent either the loss of skeletal muscle protein or the reductions in protein synthesis in alcohol-dosed animals. The evidence for increased oxidative stress in alcohol-exposed skeletal muscle is thus inconsistent. Further work into the role of ROS in alcoholic myopathy is clearly warranted. (C) 2002 Elsevier Science Inc.

Vorgaenge im Oozytenkern von Nasutitermes sp

Es werden die Vorgaenge in den generativen Kernen des Ovariums der Termite Nasutitermes sp. beginneng mit den juengsten OOgonien im Germarium bis zum reifen, nicht befruchteten Ei im Eileiter untersucht, wobei di Art Syntermes dirus zum Vergleich herngezogen wird. Es ergeben sich als Hauptresultate: 1. Germarium und Endfaden sind durch eine bindegewebige Scheidewand von einander getrennt, so dass die zentrale Kernreihe des letzteren nichts mit der Oogoniengeneration des Germariums gemeinsam hat. 2. Das Wachstum der Oogonien, Oozyten, Kernen und Nukleolen geht aus den Kurven der graphischen Darstellung der Figur 32 hervor. In den Oogonienkernen laufen die typischen Chromatinveraenderungen einer meiotischen Teilung bis zum Tetradenstadium ab. Waehrend dessen erleidet der Nukleolus nur geringfuegige Veraenderungen, bleibt waehrend der ganzen Prophasenvorgaenge erhalten und waechst, waehrend sich die Tetraden wieder aufloesen, etwa im gleichen Verhaeltnis wie der Kern (Tabelle 2). 4. Der Oozytenkern wird nicht am Ende der Dotterbildung aufgeloest und spaeter wieder in perpher Lage neu gebildet, wie von anderen Autoren mitgeteilt; er ist in jedem Stadium bis zum gereiften Ei im Ovidukt als solcher zu bobachten. 5. Es wird vermutet, dass die vorsvnaptischen Vorgaenge de Nukleolus und sein Weiterbestehen in Synapsis und Postsynapsis die zu erwartende Bildung einer meiotishchen Spindel unterbindet.

Expectations, Learning and Monetary Policy: An Overview of Recent Research

Expectations about the future are central for determination of current macroeconomic outcomes and the formulation of monetary policy. Recent literature has explored ways for supplementing the benchmark of rational expectations with explicit models of expectations formation that rely on econometric learning. Some apparently natural policy rules turn out to imply expectational instability of private agents’ learning. We use the standard New Keynesian model to illustrate this problem and survey the key results about interest-rate rules that deliver both uniqueness and stability of equilibrium under econometric learning. We then consider some practical concerns such as measurement errors in private expectations, observability of variables and learning of structural parameters required for policy. We also discuss some recent applications including policy design under perpetual learning, estimated models with learning, recurrent hyperinflations, and macroeconomic policy to combat liquidity traps and deflation.

A Model of Near-Rational Exuberance

We study how the use of judgement or “add-factors” in forecasting may disturb the set of equilibrium outcomes when agents learn using recursive methods. We isolate conditions under which new phenomena, which we call exuberance equilibria, can exist in a standard self-referential environment. Local indeterminacy is not a requirement for existence. We construct a simple asset pricing example and find that exuberance equilibria, when they exist, can be extremely volatile relative to fundamental equilibria.

Does Ricardian Equivalence Hold When Expectations are not Rational?

This paper considers the Ricardian Equivalence proposition when expectations are not rational and are instead formed using adaptive learning rules. We show that Ricardian Equivalence continues to hold provided suitable additional conditions on learning dynamics are satisfied. However, new cases of failure can also emerge under learning. In particular, for Ricardian Equivalence to obtain, agents’ expectations must not depend on government’s financial variables under deficit financing.

Notes on Agents’ Behavioral Rules Under Adaptive Learning and Studies of Monetary Policy

These notes try to clarify some discussions on the formulation of individual intertemporal behavior under adaptive learning in representative agent models. First, we discuss two suggested approaches and related issues in the context of a simple consumption-saving model. Second, we show that the analysis of learning in the NewKeynesian monetary policy model based on “Euler equations” provides a consistent and valid approach.

Fiscal Policy and Learning

Using the standard real business cycle model with lump-sum taxes, we analyze the impact of fiscal policy when agents form expectations using adaptive learning rather than rational expectations (RE). The output multipliers for government purchases are significantly higher under learning, and fall within empirical bounds reported in the literature (in sharp contrast to the implausibly low values under RE). Effectiveness of fiscal policy is demonstrated during times of economic stress like the recent Great Recession. Finally it is shown how learning can lead to dynamics empirically documented during episodes of 'fiscal consolidations.'

Baysian Model Averaging, Learning and Model Selection

Agents have two forecasting models, one consistent with the unique rational expectations equilibrium, another that assumes a time-varying parameter structure. When agents use Bayesian updating to choose between models in a self-referential system, we find that learning dynamics lead to selection of one of the two models. However, there are parameter regions for which the non-rational forecasting model is selected in the long-run. A key structural parameter governing outcomes measures the degree of expectations feedback in Muth's model of price determination.