Tight-fill fruit packing /

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Specialization and the skill premium in the 20th century

The skill premium fell substantially in the first part of the 20th century, and then rose at the end of the century. I argue that these changes are connected to the organization of production. When production is organized into large plants, jobs become routinized, favoring less skilled workers. Building on the notion that numerically controlled machines made capital more “flexible” at the end of the century, the model allows for changes in the ability of capital to do a wide variety of tasks. When calibrated to data on the distribution of plant sizes, the model can account for between half and two-thirds of the movement in the skill premium over the century. It is also in accord with a variety of industry level evidence.Technological innovations

The scale of production in technological revolutions

Many manufacturing industries, including the computer industry, have seen large increases in productivity growth rates and have experienced a reduction in average establishment size and a decrease in the variance of the sizes of plants. A vintage capital model is introduced where learning increases productivity on any given technology and firms choose when to adopt a new vintage. In the model, a rise in the rate of technological change leads to a decrease in both the mean and variance of the size distribution.Productivity

Attitude control for spacecraft Patent

Attitude control device for space vehicle

The Potential of Spaced-based High-Energy Neutrino Measurements via the Airshower Cherenkov Signal

Future space-based experiments, such as OWL and JEM-EUSO, view large atmospheric and terrestrial neutrino targets. With energy thresholds slightly above 10^19 eV for observing airshowers via air fluorescence, the potential for observing the cosmogenic neutrino flux associated with the GZK effect is limited. However, the forward Cherenkov signal associated with the airshower can be observed at much lower energies. A simulation was developed to determine the Cherenkov signal strength and spatial extent at low-Earth orbit for upward-moving airshowers. A model of tau neutrino interactions in the Earth was employed to determine the event rate of interactions that yielded a tau lepton which would induce an upward-moving airshower observable by a space-based instrument. The effect of neutrino attenuation by the Earth forces the viewing of the Earth's limb to observe the nu_tau-induced Cherenkov airshower signal at above the OWL Cherenkov energy threshold of ~10^16.5 eV for limb-viewed events. Furthermore, the neutrino attenuation limits the effective terrestrial neutrino target area to ~3x10^5 km^2 at 10^17 eV, for an orbit of 1000 km and an instrumental full Field-of-View of 45 degrees. This translates into an observable cosmogenic neutrino event rate of ~1/year based upon two different models of the cosmogenic neutrino flux, assuming neutrino oscillations and a 10% duty cycle for observation.Comment: Contribution to the 32nd ICRC, Beijing, China, August 2011; Paper#1331, 4 pages, 4 figure

Informationally Efficient Trade Barriers

Why are trade barriers often used to protect home producers, even at the cost of introducing deadweight losses from higher commodity prices? We add an informational friction to the standard textbook argument in favor of free trade, and show that trade restrictions may be a more effcient policy than a lump sum transfer to the displaced producers. Trade barriers, while generating deadweight losses, have the benefit that they do not generate a need for compensation. When the policy maker does not know the amount that should be transferred, the risk of over- compensating may make trade barrier more efficient.Trade barriers, Distortionary policies

Innovation Fertility and Patent Design

It may be advantageous to provide a variety of kinds of patent protection to heterogenous innovations. Innovations which benefit society largely through their use as building blocks to future inventions may require a different scope of protection in order to be encouraged. We model the problem of designing an optimal patent menu (scope and length) when the fertility of an innovation in generating more innovations cannot be observed. The menu of patent scope can be implemented with mandated buyout fees. Evidence of heterogeneous fertility and patent obsolescence, keys to the model, are presented using patent data from the US.

A Theory of Factor Allocation and Plant Size

In this paper we develop a theory of how factors interact at the plant level. The theory has implications for: (1) the micro foundations for capital skill complementarity (2) the relationship between factor allocation and plant size and (3) the effects of trade and growth on the skill premium. The theory is consistent with certain facts about factor allocation and factor price changes in the 19th and 20th centuries.