On post-instability processes in adiabatic shear in hot rolled steel

EXPERIMENTS carried out using a split Hopkinson torsional bar have shown that only one shear band develops in specimens of hot rolled steel which break during testing. We observed, however, that in specimens which were not deformed to failure, several fine shear bands appeared. We believe that these formed during the loading cycle before the appearance of the final shear band and were not due to the effect of unloading. So we developed a numerical model to study the evolution of shear banding from several finite amplitude disturbances (FADs) in both temperature and strain rate. This numerical model reveals the detailed processes by which the FADs evolve into a fully developed shear band and suggests that beyond instability, the so-called shear banding process consists of two stages: inhomogeneous shearing and true shear-banding. The latter is characterized by the collapse of the stress and an abrupt increase of the local shear strain rate.

New Keynesian Model Features that Can Reproduce Lead, Lag and Persistence Patterns

This paper uses a new method for describing dynamic comovement and persistence in economic time series which builds on the contemporaneous forecast error method developed in den Haan (2000). This data description method is then used to address issues in New Keynesian model performance in two ways. First, well known data patterns, such as output and inflation leads and lags and inflation persistence, are decomposed into forecast horizon components to give a more complete description of the data patterns. These results show that the well known lead and lag patterns between output and inflation arise mostly in the medium term forecasts horizons. Second, the data summary method is used to investigate a rich New Keynesian model with many modeling features to see which of these features can reproduce lead, lag and persistence patterns seen in the data. Many studies have suggested that a backward looking component in the Phillips curve is needed to match the data, but our simulations show this is not necessary. We show that a simple general equilibrium model with persistent IS curve shocks and persistent supply shocks can reproduce the lead, lag and persistence patterns seen in the data.

Profit and Cost in "Modern" Post-Marxian Profit Theory: A Case Study from Varian's "Intermediate Microeconomics"

In this paper, I examine the treatment of competitive profit of professor Varian in his textbook on Microeconomics, as a representative of the “modern” post-Marxian view on competitive profit. I show how, on the one hand, Varian defines profit as the surplus of revenues over cost and, thus, as a part of the value of commodities that is not any cost. On the other hand, however, Varian defines profit as a cost, namely, as the opportunity cost of capital, so that, in competitive conditions, the profit or income of capital is determined by the opportunity cost of capital. I argue that this second definition contradicts the first and that it is based on an incoherent conception of opportunity cost.

The New Keynesian Monetary Model: Does it Show the Comovement Between Output and Inflation in the U.S.?

Published as article in: Journal of Economic Dynamics and Control (2008), 32(May), pp. 1466-1488.

How Does the New Keynesian Monetary Model Fit in the U.S. and the Eurozone? an Indirect Inference Approach

This paper estimates a standard version of the New Keynesian monetary (NKM) model under alternative specifications of the monetary policy rule using U.S. and Eurozone data. The estimation procedure implemented is a classical method based on the indirect inference principle. An unrestricted VAR is considered as the auxiliary model. On the one hand, the estimation method proposed overcomes some of the shortcomings of using a structural VAR as the auxiliary model in order to identify the impulse response that defines the minimum distance estimator implemented in the literature. On the other hand, by following a classical approach we can further assess the estimation results found in recent papers that follow a maximum-likelihood Bayesian approach. The estimation results show that some structural parameter estimates are quite sensitive to the specification of monetary policy. Moreover, the estimation results in the U.S. show that the fit of the NKM under an optimal monetary plan is much worse than the fit of the NKM model assuming a forward-looking Taylor rule. In contrast to the U.S. case, in the Eurozone the best fit is obtained assuming a backward-looking Taylor rule, but the improvement is rather small with respect to assuming either a forward-looking Taylor rule or an optimal plan.

The Comovement between Monetary and Fiscal Policy Instruments during the Post-War Period in the U.S.

This paper empirically studies the dynamic relationship between monetary and fiscal policies by analyzing the comovements between the Fed funds rate and the primary deficit/output ratio. Simple economic thinking establishes that a negative correlation between Fed rate and deficit arises whenever the two policy authorities share a common stabilization objective. However, when budget balancing concerns lead to a drastic deficit reduction the Fed may reduce the Fed rate in order to smooth the impact of fiscal policy, which results in a positive correlation between these two policy instruments. The empirical results show (i) a significant negative comovement between Fed rate and deficit and (ii) that deficit and output gap Granger-cause the Fed funds rate during the post-Volcker era, but the opposite is not true.

Markov Switching Risk Premium and the term structure of interest rates. Empirical evidence from US post-war interest rates

This paper considers the basic present value model of interest rates under rational expectations with two additional features. First, following McCallum (1994), the model assumes a policy reaction function where changes in the short-term interest rate are determined by the long-short spread. Second, the short-term interest rate and the risk premium processes are characterized by a Markov regime-switching model. Using US post-war interest rate data, this paper finds evidence that a two-regime switching model fits the data better than the basic model. The estimation results also show the presence of two alternative states displaying quite different features.

The changing behaviour of the term structure of post-war US

Using U.S. interest rate data covering the period 1950:1-1992:7, this paper tests the rational expectations model of the term structure of interest rates. We show evidence that the rational expectations model of the term structure is supported by the data during the seventies and a period lasting from the mid-eighties to the end of the sample. However, during the …fties, sixties and a period that covers most of the Volcker’s office term (from September 1979 to April 1986) the term structure model is rejected by the data. Moreover, wefind evidence of regime changes in the short-term rate process and the term structure of interest rates. These regime switches roughly coincide with changes in the Federal Reserve chairman. The switches in monetary policy taking place when the chairmanship of the Federal Reserve changes therefore seem to play an important role in characterizing the term structure of interest rates.

Switching Regimes in the Term Structure of Interest Rates During U.S. Post-War: A case for the Lucas proof equilibrium?

Published as an article in: Studies in Nonlinear Dynamics & Econometrics, 2004, vol. 8, issue 1, pages 5.

Aquaculture Asia, Vol.13, No.2, pp.1-56, April-June 2008

Peter Edwards writes on rural aquaculture: From integrated carp polyculture to intensive monoculture in the Pearl River Delta, South China. Better management practices for Vietnamese catfish. Ipomoea aquatica – an aquaculture friendly macrophyte. A status overview of fisheries and aquaculture development in Pakistan with context to other Asian countries. The changing face of post-grad education in aquaculture: contributing to soaring production and sustainable practices. Hatchery management in Bangladesh. Production of Cirrhinus molitorella and Labeo chrysophekadion for culture based fisheries development in Lao PDR Part I: Captive spawning. Application of ipil-ipil leaf meal as feed Ingredient for monosex tilapia fry (Oreochromis niloticus) in terms of growth and economics. Fermented feed ingredients as fish meal replacer in aquafeed production Aquaculture and fishing management in coastal zone demarcation: the case of Thailand. Reservoir fisheries of freshwater prawn – success story of an emerging culture-based giant freshwater prawn fishery at Malampuzha Dam in Kerala, India. Determining and locating sea cage production area for sustainable tropical aquaculture. SPC Pacific-Asia marine fish mariculture technical workshop: “Farming Marine Fishes for our Future”. Developing Better Management Practices for Marine Finfish Aquaculture. Breeding and seed production of silver pompano (Trachinotus blochii, Lacepede) at the Mariculture Development Center of Batam. Potential of silver pomfret (Pampus argenteus) as a new candidate species for aquaculture. NACA Newsletter.

Beach monitoring project Sand Key Phase II Beach nourishment program (North Redington Beach and Redington Shores) Post-Nourishment Report Part II Offshore Profiles and Wave Data

This study presents the third post-nourishment survey (January 1989) results for the Sand Key Phase II beach nourishment project carried out in June, 1988. The monitoring program to this beach nourishment project is a joint effort between the University of South Florida and University of Florida. The field surveys include a total of 26 profiles, encompassing approximately 3 miles of shoreline extending from DNR R-96 to R-1ll. The total calculated volume loss of sand in the nourished segment (from R-99G to R-107) between the July 88 and January 89 surveys is 51,113 cubic yards, which is a loss about 9.7 percent of 529,150 cubic yards actually placed in the nourishment project. The total loss of sand computed in the entire survey area is 26,796 cubic yards, which is only 5.1 percent of the sand placed in the nourishment project. It is stressed that a part of these net volume reductions is due to the background erosion and not due to spreading losses induced by the nourishment project. (PDF contains 168 pages.)

Aquatic Vegetation, Largemouth Bass and Water Quality Responses to Low-Dose Fluridone Two Years Post Treatment

Whole-lake techniques are increasingly being used to selectively remove exotic plants, including Eurasian watermilfoil ( Myriophyllum spicatum L.). Fluridone (1-methyl-3-phenyl- 5-[3-(trifluoromethyl)phenyl]-4(1 H )-pyridinone), a systemic whole-lake herbicide, is selective for Eurasian watermilfoil within a narrow low concentration range. Because fluridone applications have the potential for large effects on plant assemblages and lake food webs, they should be evaluated at the whole-lake scale. We examined effects of low-dose (5 to 8 ppb) fluridone applications by comparing submersed plant assemblages, water quality and largemouth bass ( Micropterus salmoides ) growth rates and diets between three reference lakes and three treatment lakes one- and two-years post treatment. In the treatment lakes, fluridone reduced Eurasian watermilfoil cover without reducing native plant cover, although the duration of Eurasian watermilfoil reduction varied among treatment lakes. (PDF has 11 pages.)

The Effect of Data Revisions on the Basic New Keynesian Model

This paper proposes an extended version of the basic New Keynesian monetary (NKM) model which contemplates revision processes of output and inflation data in order to assess the importance of data revisions on the estimated monetary policy rule parameters and the transmission of policy shocks. Our empirical evidence based on a structural econometric approach suggests that although the initial announcements of output and inflation are not rational forecasts of revised output and inflation data, ignoring the presence of non well-behaved revision processes may not be a serious drawback in the analysis of monetary policy in this framework. However, the transmission of inflation-push shocks is largely affected by considering data revisions. The latter being especially true when the nominal stickiness parameter is estimated taking into account data revision processes.

An Estimated New-Keynesian Model with Unemployment as Excess Supply of Labor

Wage stickiness is incorporated to a New-Keynesian model with variable capital to drive endogenous unemployment uctuations de ned as the log di¤erence between aggregate labor supply and aggregate labor demand. We estimated such model using Bayesian econometric techniques and quarterly U.S. data. The second-moment statistics of the unemployment rate in the model give a good t to those observed in U.S. data. Our results also show that wage-push shocks, demand shifts and monetary policy shocks are the three major determinants of unemployment fl uctuations. Compared to an estimated New-Keynesian model without unemployment (Smets and Wouters, 2007): wage stickiness is higher, labor supply elasticity is lower, the slope of the New-Keynesian Phillips curve is flatter, and the importance of technology innovations on output variability increases.