937 resultados para Grazing cycles
Resumo:
This paper examines sources of cyclical movements in output, inflation and the term structure of interest rates. It employs a novel identification approach which uses the sign of the cross correlation function in response to shocks to catalog orthogonal disturbances. We find that demand shocks are the dominant source output, inflation and term structure fluctuations in six of the G-7 countries. Within the class of demand disturbances, nominal shocks are dominant, but their importance declined after 1982. Furthermore, there are no significant differences in the proportion of term structure variability explained by different structural sources at different horizons.
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In this paper we study the macroeconomic effects of an inflow oflow-skilled workers into an economy where there is capital accumulation and two types of agents. We find that there are substantial dynamic effects following unexpected migrations with adjustments that resemble those triggered by a sudden disruption of the capital stock. We look at the interrelations between these dynamic effects and three different fiscal systems for the redistribution of income and find that these schemes can change the dynamics and lead to prolonged periods of adjustments. Theaggregate welfare implications are sensitive to the welfare system: while there are welfare gains without redistribution, these gains may be turned into costs when the state engages in redistribution.
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This paper studies the generation and transmission of international cycles in a multi-country model with production and consumption interdependencies. Two sources of disturbance are considered and three channels of propagation are compared. In the short run the contemporaneous correlation of disturbances determines the main features of the transmission. In the medium run production interdependencies account for the transmission of technology shocks and consumption interdependencies account for the transmission of government shocks. Technology disturbances, which are mildly correlated across countries, are more successful than government expenditure disturbances in reproducing actual data. The model also accounts for the low cross country consumption correlations observed in the data.
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We study the contribution of money to business cycle fluctuations in the US,the UK, Japan, and the Euro area using a small scale structural monetary business cycle model. Constrained likelihood-based estimates of the parameters areprovided and time instabilities analyzed. Real balances are statistically importantfor output and inflation fluctuations. Their contribution changes over time. Models giving money no role provide a distorted representation of the sources of cyclicalfluctuations, of the transmission of shocks and of the events of the last 40 years.
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The aim of this paper is to test formally the classical business cyclehypothesis, using data from industrialized countries for the timeperiod since 1960. The hypothesis is characterized by the view that the cyclical structure in GDP is concentrated in the investment series: fixed investment has typically a long cycle, while the cycle in inventory investment is shorter. To check the robustness of our results, we subject the data for 15 OECD countries to a variety of detrending techniques. While the hypothesis is not confirmed uniformly for all countries, there is a considerably high number for which the data display the predicted pattern. None of the countries shows a pattern which can be interpreted as a clear rejection of the classical hypothesis.
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This paper theoretically and empirically documents a puzzle that arises when an RBC economy with a job matching function is used to model unemployment. The standard model can generate sufficiently large cyclical fluctuations in unemployment, or a sufficiently small response of unemployment to labor market policies, but it cannot do both. Variable search and separation, finite UI benefit duration, efficiency wages, and capital all fail to resolve this puzzle. However, either sticky wages or match-specific productivity shocks can improve the model's performance by making the firm's flow of surplus more procyclical, which makes hiring more procyclical too.
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This paper explains why trade liberalizations occur in developing countries,and why they are often reversed. It does so by focusing on the use oflobbying for protection by import competing firms as a means to postponecostly product quality upgrades to keep up with foreign competitors. Giventhe availability of a political market for import tariffs, domestic firmswill lobby for a sequence of tariffs that insulate domestic profits from awidening quality gap, thereby allowing adjustment to be postponed. But asthe contributions required by the government grow with the size of thequality gap, it will be optimal to adjust quality and to decrease thelobbying effort at some time, leading to liberalization and technologicalcatch-up. But then the equilibrium tariff will again be small and "cheap",and it will pay to start lobbying anew, until the next quality adjustment.Therefore, cycles in protection will occur as a result of the use oflobbying as a substitute for innovation. The model thus sheds new light onthe impact of the costs of protection on the effectiveness of the lobbyingeffort over time, and on their implications for the timing and the timehorizon of trade reforms in developing countries.
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The paper reports results on the effects of stylized stabilization policies on endogenously created fluctuations. A simple monetary model with intertemporally optimizing agents is considered. Fluctuations in output may occur due to fluctuations in labor supply which are again caused by volatile expectations which are ``self fulfilling'', i.e. correct given the model. It turns out that stabilization policies that are sufficiently countercyclical in the sense that government spending (on transfers or demand) depends sufficiently strongly negatively on GNP-increases can stabilize the economy at a monetary steadystate for an arbitrarily low degree of distortion of that steady state. Such stabilization has unambiguously good welfare effects and can be achieved without features such as positive lump sum taxation or negative income taxation as part of the stabilization policy.
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Business cycles are both less volatile and more synchronized with the world cycle in rich countries than in poor ones. We develop two alternative explanations based on the idea that comparative advantage causes rich countries to specialize in industries that use new technologies operated by skilled workers, while poor countries specialize in industries that use traditional technologies operated by unskilled workers. Since new technologies are difficult to imitate, the industries of rich countries enjoy more market power and face more inelastic product demands than those of poor countries. Since skilled workers are less likely to exit employment as a result of changes in economic conditions, industries in rich countries face more inelastic labour supplies than those of poor countries. We show that either asymmetry in industry characteristics can generate cross-country differences in business cycles that resemble those we observe in the data.
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We study the effects that the Maastricht treaty, the creation of the ECB, andthe Euro changeover had on the dynamics of European business cycles using a panelVAR and data from ten European countries - seven from the Euro area and threeoutside of it. There are changes in the features of European business cycles and in thetransmission of shocks. They precede the three events of interest and are more linkedto a general process of European convergence and synchronization.
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Estudio de la cantidad de alimento ingerido para tres generos de copepodos con el fin de determinar la profundidad y la hora del día que se da el máximo y mínimo de actividad alimentaria.
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Rock-paper-scissors (RPS) dynamics, which maintain genetic polymorphisms over time through negative frequency-dependent (FD) selection, can evolve in short-lived species with no generational overlap, where they produce rapid morph frequency cycles. However, most species have overlapping generations and thus, rapid RPS dynamics are thought to require stronger FD selection, the existence of which yet needs to be proved. Here, we experimentally demonstrate that two cumulative selective episodes, FD sexual selection reinforced by FD selection on offspring survival, generate sufficiently strong selection to generate rapid morph frequency cycles in the European common lizard Zootoca vivipara, a multi-annual species with major generational overlap. These findings show that the conditions required for the evolution of RPS games are fulfilled by almost all species exhibiting genetic polymorphisms and suggest that RPS games may be responsible for the maintenance of genetic diversity in a wide range of species.
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This paper focuses on the connection between the Brauer group and the 0-cycles of an algebraic variety. We give an alternative construction of the second l-adic Abel-Jacobi map for such cycles, linked to the algebraic geometry of Severi-Brauer varieties on X. This allows us then to relate this Abel-Jacobi map to the standard pairing between 0-cycles and Brauer groups (see [M], [L]), completing results from [M] in this direction. Second, for surfaces, it allows us to present this map according to the more geometrical approach devised by M. Green in the framework of (arithmetic) mixed Hodge structures (see [G]). Needless to say, this paper owes much to the work of U. Jannsen and, especially, to his recently published older letter [J4] to B. Gross.
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A monoclonal antibody CC92 (IgM), raised against a fraction of rat liver enriched in Golgi membranes, recognizes a novel Endo H-resistant 74-kD membrane glycoprotein (gp74). The bulk of gp74 is confined to the cis-Golgi network (CGN). Outside the Golgi gp74 is found in tubulovesicular structures and ER foci. In cells incubated at 37 degrees C the majority of gp74 is segregated from the intermediate compartment (IC) marker p58. However, in cells treated with organelle perturbants such as low temperature, BFA, and [AIF4]- the patterns of the two proteins become indistinguishable. Both proteins are retained in the Golgi complex at 20 degrees C and in the IC at 15 degrees C. Incubation of cells with BFA results in relocation of gp74 to p58 positive IC elements. [AIF4]- induces the redistribution of gp74 from the Golgi to p58-positive vesicles and does not retard the translocation of gp74 to IC elements in cells treated with BFA. Disruption of microtubules by nocodazol results in the rapid disappearance of the Golgi elements stained by gp74 and redistribution of the protein into vesicle-like structures. The responses of gp74 to cell perturbants are in sharp contrast with those of cis/middle and trans-Golgi resident proteins whose location is not affected by low temperatures or [AIF4]-, are translocated to the ER upon addition of BFA, and stay in slow disintegrating Golgi elements in cells treated with nocodazol. The results suggest that gp74 is an itinerant protein that resides most of the time in the CGN and cycles through the ER/IC following the pathway used by p58.