Inverse electromagnetic scattering models for sea ice

Journal ArticleInverse scattering algorithms for reconstructing the physical properties of sea ice from scattered electromagnetic field data are presented. The development of these algorithms has advanced the theory of remote sensing, particularly in the microwave region, and has the potential to form the basis for a new generation of techniques for recovering sea ice properties, such as ice thickness, a parameter of geophysical and climatological importance. Moreover, the analysis underlying the algorithms has led to significant advances in the mathematical theory of inverse problems

Incumbents and Criminals in the Indian National Legislature

Utilizing data on criminal charges lodged against candidates to the Fourteenth and Fifteenth Lok Sabha, India’s lower house of representatives, we study the conditions that resulted in approximately a quarter of members of parliament elected in 2004 and in 2009 facing or having previously faced criminal charges. Our results document that Indian political parties are more likely to select alleged criminal candidates when confronting greater electoral uncertainty and in parliamentary constituencies whose populations exhibit lower levels of literacy. We interpret the decisions of political parties to enlist known criminals as candidates as a function of the capacity of these candidates to intimidate voters. To substantiate this, we show that criminal candidates depress electoral turnout. In addition, our results suggest that India’s well-known incumbency disadvantage stems from the superior electoral performance of allegedly criminal candidates, who drive parliamentary incumbents from office. Our study raises questions for democratic theory, which claims that electoral competition improves accountability, and for the future of the Indian polity, which is experiencing a growing criminalization of the national political arena

DYNAMICS OF SELECTED TOWER DIVE TAKE-OFFS

The mechanics of platform diving, unlike those of springboard diving. have not been investigated to any great degree. Unlike the springboard, the platform provides no elastic energy to enhance the diver's momentum. At take-off the diver must achieve sufficient linear momentum to ensure the necessary height and distance to travel safely away from the platform and sufficient angular momentum to complete the required number of rotations about the transverse axis. Ground reaction forces (GRF) developed during contact with the diving platform and the body position of the diver at take-off define the magnitude and direction of the diver's momentum. The nature of rotations in springboard diving has been reported by many researchers and coaches (Fairbanks, 1963; Batterman, 1968; Stroup and Bushnell, 1969)...-tn most cases, it was felt that body Jean at take-off determined the number of rotations in the dive. Golden (1984) found that body lean at take-off increases according to the number of rotations being performed. Miller (1984) found that the height obtained in springboard diving was predominantly due to the action of the lower extremities as they accelera ted the trunk upwards. Although a number of investigators have studied springboard diving, there is an apparent Jack of information pertaining to platform diving. Furthermore, it seemes necessary to study the nature of increased rotations in platform diving. The purpose of this study was, therefore, to investigate the kinetics and kinematics of platform dive take-offs in which a rotation or multiple rotations occurred

Racial and Ethnic Differences in What Smokers Report Paying for Their Cigarettes

Smoking rates and tobacco-related health problems vary by race and ethnicity. We explore whether cigarette prices, a determinant of tobacco use, differ across racial and ethnic groups, and whether consumer behaviors influence these differences

Implications of the Optical Observations of Neutron Stars

We show that observations of pulsars with pulsed optical emission indicate that the peak flux scales according to the magnetic field strength at the light cylinder. The derived relationships indicate that the emission mechanism is common across all of the observed pulsars with periods ranging from 33ms to 385 ms and ages of 1000-300,000 years. It is noted that similar trends exist for $\gamma$ ray pulsars. Furthermore the model proposed by Pacini (1971) and developed by Pacini and Salvati (1983,1987) still has validity and gives an adequate explanation of the optical phenomena.Comment: 23 pages, 6 figures, accepted for publication in the Astrophysical Journa

Acid Vapor Weathering of Apatite and Implications for Mars

Phosphorus is an essential nutrient for terrestrial life, and therefore may be important in characterizing habitability on Mars. In addition, phosphate mobility on Mars has been postulated as an indicator of early aqueous activity [1]. Rock surfaces analyzed by the Spirit Mars Exploration Rover indicate elemental concentrations consistent with the loss of a phosphate-containing mineral [2], and the highly altered Paso Robles deposit contains ~5% P2O5, modeled as 8-10 % phosphate [3]. Depending on the pH of the solution, phosphate can exist as one of four charge states, which can affect its solubility, reactivity and mobility. Phosphate may therefore prove a useful and interesting tracer of alteration conditions on Mars. Acid vapor weathering has been previously studied as a potentially important process on Mars [4-6], and Paso Robles may have been formed by reaction of volcanic vapors with phosphate-bearing rock [3, 7]. Here we present preliminary results of acid vapor reactions in a Parr vessel [6] using fluorapatite, olivine and glass as single phases and in a mixture

A high resolution, hard x-ray photoemission investigation of La_(2-2x)Sr_(1+2x)Mn_2O_7 (0.30<x<0.50): on microscopic phase separation and the surface electronic structure of a bilayered CMR manganite

Photoemission data taken with hard x-ray radiation on cleaved single crystals of the bilayered, colossal magnetoresistant manganite La_(2-2x)Sr_(1+2x)Mn_2O_7 (LSMO) with 0.30<x<0.50 are presented. Making use of the increased bulk-sensitivity upon hard x-ray excitation it is shown that the core level footprint of the electronic structure of the LSMO cleavage surface is identical to that of the bulk. Furthermore, by comparing the core level shift of the different elements as a function of doping level x, it is shown that microscopic phase separation is unlikely to occur for this particular manganite well above the Curie temperature.Comment: 7 pages, 5 figure