Multiplex electric discharge gas laser system

A multiple pulse electric discharge gas laser system is described in which a plurality of pulsed electric discharge gas lasers are supported in a common housing. Each laser is supplied with excitation pulses from a separate power supply. A controller, which may be a microprocessor, is connected to each power supply for controlling the application of excitation pulses to each laser so that the lasers can be fired simultaneously or in any desired sequence. The output light beams from the individual lasers may be combined or utilized independently, depending on the desired application. The individual lasers may include multiple pairs of discharge electrodes with a separate power supply connected across each electrode pair so that multiple light output beams can be generated from a single laser tube and combined or utilized separately

A Preliminary Check-List of the Marine Algae of the Moss Landing Jetty: An Annotated Floristic Compilation. Annual Report, Part 7, 1973

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How legislators respond to localized economic shocks: evidence from Chinese import competition

We explore the effects of localized economic shocks from trade on roll-call behavior and electoral outcomes in the US House, 1990–2010. We demonstrate that economic shocks from Chinese import competition—first studied by Autor, Dorn, and Hanson—cause legislators to vote in a more protectionist direction on trade bills but cause no change in their voting on all other bills. At the same time, these shocks have no effect on the reelection rates of incumbents, the probability an incumbent faces a primary challenge, or the partisan control of the district. Though changes in economic conditions are likely to cause electoral turnover in many cases, incumbents exposed to negative economic shocks from trade appear able to fend off these effects in equilibrium by taking strategic positions on foreign-trade bills. In line with this view, we find that the effect on roll-call voting is strongest in districts where incumbents are most threatened electorally. Taken together, these results paint a picture of responsive incumbents who tailor their roll-call positions on trade bills to the economic conditions in their districts

There is no MacWilliams identity for convolutional codes

An example is provided of two convolutional codes that have the same transmission gain but whose dual codes do not. This shows that no analog of the MacWilliams identity for block codes can exist relating the transmission gains of a convolutional code and its dual

Toward a Minimum Branching Fraction for Dark Matter Annihilation into Electromagnetic Final States

Observational limits on the high-energy neutrino background have been used to place general constraints on dark matter that annihilates only into standard model particles. Dark matter particles that annihilate into neutrinos will also inevitably branch into electromagnetic final states through higher-order tree and loop diagrams that give rise to charged leptons, and these charged particles can transfer their energy into photons via synchrotron radiation or inverse Compton scattering. In the context of effective field theory, we calculate the loop-induced branching ratio to charged leptons and show that it is generally quite large, typically >1%, when the scale of the dark matter mass exceeds the electroweak scale, M_W. For a branching fraction >3%, the synchrotron radiation bounds on dark matter annihilation are currently stronger than the corresponding neutrino bounds in the interesting mass range from 100 GeV to 1 TeV. For dark matter masses below M_W, our work provides a plausible framework for the construction of a model for "neutrinos only" dark matter annihilations.Comment: 18 pages, 4 figures, discussion added, matches version in Phys. Rev.

The majority-party disadvantage: revising theories of legislative organization

Dominant theories of legislative organization in the U.S. rest on the notion that the majority party arranges legislative matters to enhance its electoral fortunes. Yet, we find little evidence for a short-term electoral advantage for the majority party in U.S. state legislatures. Furthermore, there appears to be a pronounced downstream majority-party disadvantage. To establish these findings, we propose a technique for aggregating the results of close elections to obtain as-if random variation in majority-party status. We argue that the results from this approach are consistent with a phenomenon of inter-temporal balancing, which we link to other forms of partisan balancing in U.S. elections. The article thus necessitates revisions to our theories of legislative organization, offers new arguments for balancing theories, and lays out an empirical technique for studying the effects of majority-party status in legislative contexts

Do Labor Markets Provide Enough Short Hour Jobs? An Analysis of Work Hours and Work Incentives

This paper examines the role that work incentives play in the determination of work hours. Following previous research by Lang (1989), we use a conventional efficiency wage model to analyze how firms respond to worker preferences regarding wage-hours packages. We find that when workers are homogeneous, the role of worker preferences in determining work hours is similar to the simple neoclassical model of labor supply. For instance, if worker preferences shift in favor of shorter hours, firms will respond by offering jobs entailing shorter hours. When workers have heterogeneous preferences, however, employers will want to use a worker's hours preferences as a signal for the responsiveness of the worker to the work incentives used by the firm, and workers in turn may not reveal their hours preferences. Our key finding in this instance is that the labor market equilibrium may be characterized by a sub-optimal number of short-hour jobs. This shortage of short-hour jobs is likely to be found in high wage labor markets.

"When Knowledge is an Asset: Explaining the Organizational Structure of Large Law Firms"

We study the economics of employment relationships through theoretical and empirical analyses of an unusual set of firms, large law firms. Our point of departure is the "property rights" approach that emphasizes the centrality of ownership's legal rights to control important, nonhuman assets of the enterprise. From this perspective, large law firms are an interesting and potentially important object of study, because the most valuable assets of these firms take the form of knowledge--particularly knowledge of the needs and interests of clients. We argue that the two most distinctive organizational features of large law firms, the use of "up or out" promotion contests and the practice of having winners become residual claimants in the firm, emerge naturally in this setting. In addition to explaining otherwise anomalous features of the up-or-out partnership system, this paper suggests a general framework for analyzing organizations where assets reside in the brains of employees.