Sample holder support for microscopes

A sample filter holder is disclosed for use with a microscope for holding the filter in a planar condition on the stage of the microscope so that automatic focusing of the microscope can be performed on particle samples dispersed on the filter. The holder includes a base having a well that communicates with an inlet port which is connected to a suction pump. A screen assembly is positioned within the well. The screen assembly includes a disk having a screen positioned on its top surface and secured to the disk at the peripheral edge of the screen. Small bores allow the outer surface of the screen to communicate with the well. The filter is placed on the screen and is held in a flat disposition by the suction forces

Gillraker analysis and speciation in the thread herring genus Opisthonema

ENGLISH: The thread herrings, genus Opisthonema, family Clupeidae, are marine fishes that occur only in tropical and subtropical waters off both coasts of the American continent. The genus is composed of one Atlantic species and four Pacific species. Opisthonema oglinum (LeSueur), the single species in the western Atlantic Ocean, occurs from Brazil to Massachusetts, at Bermuda, and throughout the West Indies. Opisthonema libertate (Günther), Opisthonema bulleri (Regan), and Opisthonema medirastre, new species, are Pacific coastal species which occur together from Peru to Mexico (with at least one occasionally in California). Opisthonema berlangai, new species, is confined to the vicinity of the Galapagos Islands. SPANISH: Los arenques de hebra, género Opisthonema, familia Clupeidae, son peces marinos que se encuentran sólo en aguas tropicales y subtropicales cerca a ambas costas del continente americano. El género está compuesto de una especie en el Atlántico y de cuatro en el Pacifico. Opisthonema oglinum (LeSueur), única especie que medra el Océano Atlántico occidental, se encuentra del Brasil a Massachusetts, en Bermuda, y las Indias Occidentales. Opisthonema libertate (Günther), Opisthonema bulleri (Regan), y Opisthonema medirastre, especie nueva, son especies costaneras del Pacífico que aparecen entremezcladas del Perú a México (ocasionalmente por lo menos una de ellas en California). Opisthonema berlangai, especie nueva, está confinada a la vecindad de las Islas Galápagos

Long-Range Spectral Statistics of Classically Integrable Systems --Investigation along the Line of the Berry-Robnik Approach--

Extending the argument of Ref.\citen{[4]} to the long-range spectral statistics of classically integrable quantum systems, we examine the level number variance, spectral rigidity and two-level cluster function. These observables are obtained by applying the approach of Berry and Robnik\cite{[0]} and the mathematical framework of Pandey \cite{[2]} to systems with infinitely many components, and they are parameterized by a single function $\bar{c}$, where $\bar{c}=0$ corresponds to Poisson statistics, and $\bar{c}\not=0$ indicates deviations from Poisson statistics. This implies that even when the spectral components are statistically independent, non-Poissonian spectral statistics are possible.Comment: 13 pages, 4 figure

Adaptive Quantum Measurements of a Continuously Varying Phase

We analyze the problem of quantum-limited estimation of a stochastically varying phase of a continuous beam (rather than a pulse) of the electromagnetic field. We consider both non-adaptive and adaptive measurements, and both dyne detection (using a local oscillator) and interferometric detection. We take the phase variation to be \dot\phi = \sqrt{\kappa}\xi(t), where \xi(t) is \delta-correlated Gaussian noise. For a beam of power P, the important dimensionless parameter is N=P/\hbar\omega\kappa, the number of photons per coherence time. For the case of dyne detection, both continuous-wave (cw) coherent beams and cw (broadband) squeezed beams are considered. For a coherent beam a simple feedback scheme gives good results, with a phase variance \simeq N^{-1/2}/2. This is \sqrt{2} times smaller than that achievable by nonadaptive (heterodyne) detection. For a squeezed beam a more accurate feedback scheme gives a variance scaling as N^{-2/3}, compared to N^{-1/2} for heterodyne detection. For the case of interferometry only a coherent input into one port is considered. The locally optimal feedback scheme is identified, and it is shown to give a variance scaling as N^{-1/2}. It offers a significant improvement over nonadaptive interferometry only for N of order unity.Comment: 11 pages, 6 figures, journal versio

Positive dc to positive dc converter Patent

Conversion of positive dc voltage to positive dc voltage of lower amplitud

Implementation of multipartite unitary operations with limited resources

A general method for implementing weakly entangling multipartite unitary operations using a small amount of entanglement and classical communication is presented. For the simple Hamiltonian \sigma_z\otimes\sigma_z this method requires less entanglement than previously known methods. In addition, compression of multiple operations is applied to reduce the average communication required.Comment: 7 pages, 4 figures, comments welcom

System analysis and integration studies for a 15-micron horizon radiance measurement experiment

Systems analysis and integration studies for 15-micron horizon radiance measurement experimen

Taxes and Entrepreneurial Activity: Theory and Evidence for the U.S.

Entrepreneurial activity is presumed to generate important spillovers, potentially justifying tax subsidies. How does the tax law affect individual incentives? How much of an impact has it had in practice? We first show theoretically that taxes can affect the incentives to be an entrepreneur due simply to differences in tax rates on business vs. wage and salary income, due to differences in the tax treatment of losses vs. profits through a progressive rate structure and through the option to incorporate, and due to risk-sharing with the government. We then provide empirical evidence using U.S. individual tax return data that these aspects of the tax law have had large effects on actual behavior.

Description of the three axis low-g accelerometer package

The three axis low-g accelerometer package designed for use on the Space Processing Application Rocket (SPAR) Program is described. The package consists of the following major sections: (1) three Kearfott model 2412 accelerometers mounted in an orthogonal triad configuration on a temperature controlled, thermally isolated cube, (2) the accelerometer servoelectronics (printed circuit cards PC-6 through PC-12), and (3) the signal conditioner (printed circuit cards PC-15 and PC-16). The measurement range is 0 + or - 0.031 g with a quantization of 1.1 x 10 to the 7th power g. The package was flown successfully on six SPAR launches with the Black Brant booster. These flights provide approximately 300 s of free fall or zero-g environment