2,422 research outputs found
The Calibration of CES Production Functions
This note addresses some issues that arise when using 'normalized' CES production functions, an approach that has become popular in the literature. The results of Klump and de La Grandville (2000) provide a simple way to calibrate the parameters of the CES production function when the necessary data are available. But some of the other applications of normalized CES production functions appear problematic, especially when used to argue that productivity is increasing in the elasticity of substitution.CES production functions, elasticity of substitution, normalization
Finite-Time Singularity Signature of Hyperinflation
We present a novel analysis extending the recent work of Mizuno et al. [2002]
on the hyperinflations of Germany (1920/1/1-1923/11/1), Hungary
(1945/4/30-1946/7/15), Brazil (1969-1994), Israel (1969-1985), Nicaragua
(1969-1991), Peru (1969-1990) and Bolivia (1969-1985). On the basis of a
generalization of Cagan's model of inflation based on the mechanism of
``inflationary expectation'' or positive feedbacks between realized growth rate
and people's expected growth rate, we find that hyperinflations can be
characterized by a power law singularity culminating at a critical time .
Mizuno et al.'s double-exponential function can be seen as a discrete time-step
approximation of our more general nonlinear ODE formulation of the price
dynamics which exhibits a finite-time singular behavior. This extension of
Cagan's model, which makes natural the appearance of a critical time , has
the advantage of providing a well-defined end of the clearly unsustainable
hyperinflation regime. We find an excellent and reliable agreement between
theory and data for Germany, Hungary, Peru and Bolivia. For Brazil, Israel and
Nicaragua, the super-exponential growth seems to be already contaminated
significantly by the existence of a cross-over to a stationary regime.Comment: Latex 21 pages including 2 tables and 7 eps figure
Genomic and proteomic profiling of responses to toxic metals in human lung cells.
Examining global effects of toxic metals on gene expression can be useful for elucidating patterns of biological response, discovering underlying mechanisms of toxicity, and identifying candidate metal-specific genetic markers of exposure and response. Using a 1,200 gene nylon array, we examined changes in gene expression following low-dose, acute exposures of cadmium, chromium, arsenic, nickel, or mitomycin C (MMC) in BEAS-2B human bronchial epithelial cells. Total RNA was isolated from cells exposed to 3 M Cd(II) (as cadmium chloride), 10 M Cr(VI) (as sodium dichromate), 3 g/cm2 Ni(II) (as nickel subsulfide), 5 M or 50 M As(III) (as sodium arsenite), or 1 M MMC for 4 hr. Expression changes were verified at the protein level for several genes. Only a small subset of genes was differentially expressed in response to each agent: Cd, Cr, Ni, As (5 M), As (50 M), and MMC each differentially altered the expression of 25, 44, 31, 110, 65, and 16 individual genes, respectively. Few genes were commonly expressed among the various treatments. Only one gene was altered in response to all four metals (hsp90), and no gene overlapped among all five treatments. We also compared low-dose (5 M, noncytotoxic) and high-dose (50 M, cytotoxic) arsenic treatments, which surprisingly, affected expression of almost completely nonoverlapping subsets of genes, suggesting a threshold switch from a survival-based biological response at low doses to a death response at high doses
Perturbed Spherically Symmetric Dust Solution of the Field Equations in Observational Coordinates with Cosmological Data Functions
Using the framework for solving the spherically symmetric field equations in
observational coordinates given in Araujo and Stoeger (1999), their formulation
and solution in the perturbed FLRW sperically symmetric case with observational
data representing galaxy redshifts, number counts and observer area distances,
both as functions of redshift on our past light cone, are presented. The
importance of the central conditions, those which must hold on our world line
C, is emphasized. In detailing the solution for these perturbations, we discuss
the gauge problem and its resolution in this context, as well as how errors and
gaps in the data are propagated together with the genuine perturbations. This
will provide guidance for solving, and interpreting the solutions of the more
complicated general perturbation problem with observational data on our past
light cone.Comment: Latex 23 pages, no figures, submitted to Astrophysical Journa
Suicidal Ideation and Psychological Dating Violence Victimization-A Short Report
As the second leading cause of death among Americans aged 10 to 34, suicide is a serious public health concern. One potential predictor of suicidality is dating violence (DV) victimization, such as any physical, psychological, or sexual abuse by a current or former intimate partner. However, little longitudinal data exists on the relationship between suicidal ideation and DV. To address this gap in knowledge, we leverage data from two years of our longitudinal stud
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