Computer programs for antenna feed system design and analysis

Fourteen computer programs have been developed for antenna feed system design and analysis. The programs cover a large spectrum of feed design problems, from primary feed pattern synthesis to the farfield pattern of the main reflector, including analyses of structural distortions

[Review of] Gill Bottomley and Marie de Lepervanche, eds. Ethnicity, Class and Gender in Australia

North American social scientists can benefit from comparing immigration in their own countries to immigration in Australia, another former English colony bordering on the Pacific Ocean. Bottomley and de Lepervanche have assembled a very useful set of theoretical discussions and data-based studies which provide a starting point for such comparisons. The collection focuses on the relationship of immigrants to the institutions and ideologies of the dominant culture in Australia. The underlying perspective is Marxist, although this is not made explicit by every contributor. In addition to a historical review of immigration policies, the authors present critiques of policies and the social science theories that go with them, as well as descriptive and analytical accounts of immigrants in particular institutional contexts such as labor, law and education

High-gain antenna with singly-curved reflector

Reflector collects energy over large region of space and focuses it toward small region where antenna feed is located. When incident energy is in form of plane wave, logical choice for shape of reflecting surface is paraboloid which converts plane wave into spherical wave that converges at a point

Dual waveguide mode source having control means for adjusting the relative amplitude of two modes Patent

Dual waveguide mode source for controlling amplitudes of two mode

[Review of] Edward A. Tiryakian and Ronald Rogowski, eds. New Nationalisms of the Developed West: Toward Explanation

Tiryakian and Rogowski have edited a strong and useful collection of nine theoretical and seven comparative articles on nationalism in advanced industrial societies in the West. What is new in the presentations in this work is the systematic comparison of a number of nationalist movements that have been treated hitherto as separate cases. The writers are focusing on nationalism in advanced capitalist economies rather than in developing nations or socialist industrial states, so examples are drawn from Quebec and Western Europe. A great strength of the collection lies in the richness of the analysis produced by contributors drawn from a range of disciplines, including political science, sociology, anthropology and international relations

Radiation-hydrodynamics simulations of surface convection in low-mass stars: connections to stellar structure and asteroseismology

Radiation-hydrodynamical simulations of surface convection in low-mass stars can be exploited to derive estimates of i) the efficiency of the convective energy transport in the stellar surface layers; ii) the convection-related photometric micro-variability. We comment on the universality of the mixing-length parameter, and point out potential pitfalls in the process of its calibration which may be in part responsible for the contradictory findings about its variability across the Hertzsprung-Russell digramme. We further comment on the modelling of the photometric micro-variability in HD49933 - one of the first main COROT targets.Comment: 6 pages, 5 figures, Proceedings paper of IAU Symposium 25

Computer Programs for Antenna Feed System Design and Analysis. Volume I - Programs and Sample Cases

Computer programs and sample cases for antenna feed system design and analysi

Factor analytic reduction of the carotid-cardiac baroreflex parameters

An accepted method for measuring the responsiveness of the carotid-cardiac baroreflex to arterial pressure changes is to artificially stimulate the baroreceptors in the neck. This is accomplished by using a pressurized neck cuff which constricts and distends the carotid artery and subsequently stimulates the baroreceptors. Nine physiological responses to this type of stimulation are quantified and used as indicators of the baroreflex. Thirty male humans between the ages 27 and 46 underwent the carotid-cardiac baroreflex test. The data for the nine response parameters were analyzed by principle component factor analysis. The results of this analysis indicated that 93 percent of the total variance across all nine parameters could be explained in four dimensions. Examination of the factor loadings following an orthogonal rotation of the principle components indicated four well defined dimensions. The first two dimensions reflected location points for R-R interval and carotid distending pressure respectively. The third dimension was composed of measures reflecting the gain of the reflex. The fourth dimension was the ratio of the resting R-R interval to R-R interval during simulated hypertension. The data suggests that the analysis of all nine baroreflex parameters is redundant

3D hydrodynamical CO5BOLD model atmospheres of red giant stars: I. Atmospheric structure of a giant located near the RGB tip

We investigate the character and role of convection in the atmosphere of a prototypical red giant located close to the red giant branch (RGB) tip with atmospheric parameters, Teff=3660K, log(g)=1.0, [M/H]=0.0. Differential analysis of the atmospheric structures is performed using the 3D hydrodynamical and 1D classical atmosphere models calculated with the CO5BOLD and LHD codes, respectively. All models share identical atmospheric parameters, elemental composition, opacities and equation-of-state. We find that the atmosphere of this particular red giant consists of two rather distinct regions: the lower atmosphere dominated by convective motions and the upper atmosphere dominated by wave activity. Convective motions form a prominent granulation pattern with an intensity contrast (~18%) which is larger than in the solar models (~15%). The upper atmosphere is frequently traversed by fast shock waves, with vertical and horizontal velocities of up to Mach ~2.5 and ~6.0, respectively. The typical diameter of the granules amounts to ~5Gm which translates into ~400 granules covering the whole stellar surface. The turbulent pressure in the giant model contributes up to ~35% to the total (i.e., gas plus turbulent) pressure which shows that it cannot be neglected in stellar atmosphere and evolutionary modeling. However, there exists no combination of the mixing-length parameter and turbulent pressure that would allow to satisfactorily reproduce the 3D temperature-pressure profile with 1D atmosphere models based on a standard formulation of mixing-length theory.Comment: 13 pages, 18 figures, accepted for publication in A&