The Adjusted Solow Residual and Asset Returns

The purpose of this study is to examine the effects of a measured aggregate productivity shock on asset returns. To achieve this, a simple equilibrium business cycle model is presented to show that an aggregate productivity shock can be identi?ed as a factor affecting asset returns. The paper uses the Solow residual to measure productivity changes, but deviates from standard practice by incorporating variations in capital utilization rates. The paper ?rst develops the theoretical link between productivity shocks and asset returns with no adjustment costs, and then tests that link with the two measures of productivity, the Solow residual with and without variation in capital utilization. Results based on U.S post-war data show signi?cant differences in the dynamic impacts of these two measures of productivity. The VAR evidence suggests that technology changes, measured with variation in capital utilization, have a delayed impact on asset returns, a distinct ?nding. Finally, policy implications of the ?ndings are discussed.

"Precautionary Saving under LiquidityConstraints: Evidence from Rural Pakistan"

This paper investigates precautionary saving under liquidity constraints in Pakistan using household panel data. In particular, while we estimates Kimball's (1990) prudence parameter, we deviate from Dynan's (1993) framework by explicitly considering liquidity constraints, as in Zeldes (1989). By doing so,we attempt to diffeerentiate the standard precautionary saving caused by uncertainty from the oneduetoliquidity constraints. Furthermore, endogenous liquidity constraints are considered to resolve issues of selection biases. In this study, we document substantial evidence of the presence of precautionary saving in Pakistan. More specifically, the estimated prudence is significantly higher for liquidity-constrainedhouse-holds as compared with unconstrained ones. The results support the emerging view that facilitating saving may often be more important than finding better ways of lending to the poor.

"The Degree of Precautionary Saving: A Reexamination"

Extending Dynan's methodology (1993), we show that a significant frac tion of the prudence parameter puzzle can be explained by a downward omitted variable bias. Further, the estimated prudence is substantially higher for liquidity-constrained households.

Reactive modification and crystallization behavior of foamed poly(butylene terephthalate)

The objective of this study is to investigate the feasibility of preparing low density foams based on poly(butylene terephthalate) (PBT) through modification of its molecular structure and rheological characteristics by reactive extrusion. The scientific and/or engineering interpretation of the experimental data was based on fundamentals of extrusion, crystallization mechanisms, as well as information on reactivity and tendency toward degradation of PBT. As a preliminary study, the extrusion foaming behavior of a commercial linear semi-crystalline PBT with a chemical blowing agent (CBA) was investigated. Foam characteristics were functions of extrusion operational variables, such as die set temperature and screw speed. Gas solubility and CBA decomposition kinetics were found to be key elements for controlling and optimizing the quality of the foamed polymer. Initially, the linear PBT polymer was reactively modified using a tri-functional epoxide in a batch mixer to produce a branched structure with a higher molecular weight (MW) and a broader molecular weight distribution (MWD) as evidenced by rheological analysis. These experiments provided information on the PBT/modifier reaction kinetics. Chain branching was then carried out by single screw extrusion, where the competing degradative chain scission reaction needed to be taken into account. Applications of fundamentals of extrusion theory to the reactive extrusion process enabled the optimization of the extrusion operational conditions. The optimization led to the production of a branched polymer with viscoelastic characteristics suitable for low density extrusion foaming by injection of a physical blowing agent (PBA). The branched product made under the optimized conditions could be foamed to densities as low as 0.33 g/cc and showed high expansion ratio of 4.0 and cell structure resistant to coalescence. The possibility of overlap of the polymer crystal formation with the nucleation/growth of gaseous cells was investigated based on theoretical predictions. Slow pressure drop rate was shown to decrease cell nucleation rate. Fast crystallization rate stabilized cell morphology. The occurrence of flow induced crystallization during bubble formation was investigated, to our knowledge, for the first time. Smaller size spherulitic structures at the bubble walls of the branched PBT compared with the linear polymer, suggested longer crystal nuclei lifetime, which may indicate that the formation of the crystalline structures was affected by the bi-axial deformation occurring during bubble growth

"The Adjusted Solow Residual and Asset Returns"

The purpose of this study is to examine the effects of a measured aggregate productivity shock on asset returns. To achieve this, a simple equilibrium business cycle model is presented to show that an aggregate productivity shock can be identified as a factor affecting asset returns. The paper uses the Solow residual to measure productivity changes, but deviates from standard practice by incorporating variations in capital utilization rates. The paper first develops the theoretical link between productivity shocks and asset returns with no adjustment costs, and then tests that link with the two measures of productivity, the Solow residual with and without variation in capital utilization. Results based on U.S post-war data show significant differences in the dynamic impacts of these two measures of productivity. The VAR evidence suggests that technology changes, measured with variation in capital utilization, have a delayed impact on asset returns, a distinct finding. Finally, policy implications of the findings are discussed.

The Adjusted Solow Residual and Asset Returns (Subsequently published in "Eastern Economic Journal", 2007, 33,(2), pp. 231-255. )

The purpose of this study is to examine the effects of a measured aggregate productivity shock on asset returns. To achieve this, a simple equilibrium business cycle model is presented to show that an aggregate productivity shock can be identified as a factor affecting asset returns. The paper uses the Solow residual to measure productivity changes, but deviates from standard practice by incorporating variations in capital utilization rates. The paper first develops the theoretical link between productivity shocks and asset returns with no adjustment costs, and then tests that link with the two measures of productivity, the Solow residual with and without variation in capital utilization. Results based on U.S post-war data show significant differences in the dynamic impacts of these two measures of productivity. The VAR evidence suggests that technology changes, measured with variation in capital utilization, have a delayed impact on asset returns, a distinct finding. Finally, policy implications of the findings are discussed.

Phosphorylated claspin interacts with a phosphate-binding site in the kinase domain of Chk1 during ATR-mediated activation

Claspin is essential for the ATR-dependent activation of Chk1 in Xenopus egg extracts containing incompletely replicated or UV-damaged DNA. The activated form of Claspin contains two repeated phosphopeptide motifs that mediate its binding to Chk1. We show that these phosphopeptide motifs bind to Chk1 by means of its N-terminal kinase domain. The binding site on Chk1 involves a positively charged cluster of amino acids that contains lysine 54, arginine 129, threonine 153, and arginine 162. Mutagenesis of these residues strongly compromises the ability of Chk1 to interact with Claspin. These amino acids lie within regions of Chk1 that are involved in various aspects of its catalytic function. The predicted position on Chk1 of the phosphate group from Claspin corresponds to the location of activation-loop phosphorylation in various kinases. In addition, we have obtained evidence that the C-terminal regulatory domain of Chk1, which does not form a stable complex with Claspin under our assay conditions, nonetheless has some role in Claspin-dependent activation. Overall, these results indicate that Claspin docks with a phosphate-binding site in the catalytic domain of Chk1 during activation by ATR. Phosphorylated Claspin may mimic an activating phosphorylation of Chk1 during this process

Did the Credit Crunch in Japan Affect Household Welfare? An Augmented Euler Equation Approach Using Type 5 Tobit Model

We investigate whether the credit crunch in Japan affected household welfare and the manner in which it did. We augment the theoretical framework of a consumption Euler equation with endogenous credit constraints and estimate it with household panel data for 1993-1999, generating several empirical findings. First, a small portion of the people faced credit constraints in Japan before and after the financial crisis in 1997. Accordingly, our results reject the standard consumption Euler equation. Second, the credit crunch affected household welfare negatively, albeit not seriously, after 1997. Our results corroborate that the credit crunch in Japan was supply-driven.