17,651 research outputs found
Individual and Aggregate Money Demands
I construct a model in which money and bond holdings are consistent with individual decisions and aggregate variables such as production and interest rates. The agents are infinitely-lived, have constant-elasticity preferences, and receive a fraction of their income in money. Each agent solves a Baumol-Tobin money management problem. Markets are segmented because financial frictions make agents trade bonds for money at different times. Trading frequency, consumption, government decisions and prices are mutually consistent. An increase in inflation, for example, implies higher trading frequency, more bonds sold to account for seigniorage, and lower real balances. JEL codes:E3, E4, E5money demand, cash management, inventory problem, market segmentation
Taxes and Labor Supply: Portugal, Europe, and the United States
I relate hours worked with taxes on consumption and labor for Portugal, France, Spain, United Kingdom and United States. From 1986 to 2001, hours per worker in Portugal decreased from 35.1 to 32.6. With the parameters for Portugal, the model predicts hours worked in 2001 with an error of only 12 minutes from the actual hours. Across countries, most predictions differ from the data by one hour or less. The model is not sensible to special assumptions on the parameters. I calculate the long run effects of taxes on consumption, hours, capital and welfare for Portugal. I extend the model to discuss implications for Social Security. I discuss the steady state and the transition from a pay-as-yougo to a fully funded system. JEL codes:E6, H3labor supply, consumption tax, labor income tax
Taxes and Labor Supply: Portugal, Europe, and the United States (Conference Version)
I relate hours worked with taxes on consumption and labor. I propose a model and compare its predictions for Portugal, France, Spain, United Kingdom and United States. Hours per worker in Portugal decreased from 35.1 in 1986 to 32.6 in 2001. With only the parameters and the taxes for Portugal, the model predicts the hours worked in 2001 with an error of only 12 minutes from the actual hours. Across countries, most predictions differ from the data by one hour or less. The model is able to explain the trend in hours with only the changes in taxes. JEL codes:labor supply, consumption tax, labor income tax
Thermodynamic cost of external control
Artificial molecular machines are often driven by the periodic variation of
an external parameter. This external control exerts work on the system of which
a part can be extracted as output if the system runs against an applied load.
Usually, the thermodynamic cost of the process that generates the external
control is ignored. Here, we derive a refined second law for such small
machines that include this cost, which is, for example, generated by free
energy consumption of a chemical reaction that modifies the energy landscape
for such a machine. In the limit of irreversible control, this refined second
law becomes the standard one. Beyond this ideal limiting case, our analysis
shows that due to a new entropic term unexpected regimes can occur: The control
work can be smaller than the extracted work and the work required to generate
the control can be smaller than this control work. Our general inequalities are
illustrated by a paradigmatic three-state system.Comment: 11 pages, 3 figure
Coherence of Biochemical Oscillations is Bounded by Driving Force and Network Topology
Biochemical oscillations are prevalent in living organisms. Systems with a
small number of constituents cannot sustain coherent oscillations for an
indefinite time because of fluctuations in the period of oscillation. We show
that the number of coherent oscillations that quantifies the precision of the
oscillator is universally bounded by the thermodynamic force that drives the
system out of equilibrium and by the topology of the underlying biochemical
network of states. Our results are valid for arbitrary Markov processes, which
are commonly used to model biochemical reactions. We apply our results to a
model for a single KaiC protein and to an activator-inhibitor model that
consists of several molecules. From a mathematical perspective, based on strong
numerical evidence, we conjecture a universal constraint relating the imaginary
and real parts of the first non-trivial eigenvalue of a stochastic matrix.Comment: 12 pages, 13 figure
Basalt depths in lunar basins using impact craters as stratigraphic probes: Evaluation of a method using orbital geochemical data
A rare look at the chemical composition of subsurface stratigraphy in lunar basins filled with mare basalt is possible at fresh impact craters. Mg/Al maps from orbital X-ray flourescence measurements of mare areas indicate chemical anomalies associated with materials ejected by large post-mare impacts. A method of constraining the wide-ranging estimates of mare basalt depths using the orbital MG/Al data is evaluated and the results are compared to those of investigators using different indirect methods. Chemical anomalies at impact craters within the maria indicate five locations where higher Mg/Al basalt compositions may have been excavated from beneath the surface layer. At eight other locations, low Mg/Al anomalies suggest that basin-floor material was ejected. In these two cases, the stratigraphic layers are interpreted to occur at depths less than the calculated maximum depth of excavation. In five other cases, there is no apparent chemical change between the crater and the surrounding mare surface. This suggests homogeneous basalt compositions that extend down to the depths sampled, i.e., no anorthositic material that might represent the basin floor was exposed
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