Persistence of Antarctic polar stratospheric clouds

The persistence of Polar Stratospheric Clouds (PSCs) observed by the Stratospheric Aerosol Measurement (SAM) 2 satellite sensor over a 9-year period is compared and contrasted. Histograms of the SAM 2 1.0 micron extinction ratio data (aerosol extinction normalized by the molecular extinction) at an altitude of 18 km in the Antarctic have been generated for three 10-day periods in the month of September. Statistics for eight different years (1979 to 1982 and 1984 to 1987) are shown in separate panels for each figure. Since the SAM 2 system is a solar occultation experiment, observations are limited to the edge of the polar night and no measurements are made deep within the vortex where temperatures could be colder. For this reason, use is made of the NMC global gridded fields and the known temperature-extinction relationship to infer additional information on the occurrence and areal coverage of PSCs. Calculations of the daily areal coverage of the 195 K isotherm will be presented for this same period of data. This contour level lies in the range of the predicted temperature for onset of the Type 1 particle enhancement mode at 50 mb (Poole and McCormick, 1988b) and should indicate approximately when formation of the binary HNO3-H2O particles begins

Antarctic measurements of ozone, water vapor, and aerosol extinction by Sage 2 in the spring of 1987

Recent measurements of ozone, water vapor, and aerosol extinction from the spring of 1987 are presented and compared to 1985 and 1986. The observed changes to variations in meteorological conditions in the vortex for these three years are noted. March ozone data at similar latitudes for these three years will be used to investigate coupling between severity of the springtime depletion and early fall values. Researchers also investigate correlations between the measured species of water vapor, ozone, and aerosols throughout the vortex region

Depth mapping of integral images through viewpoint image extraction with a hybrid disparity analysis algorithm

Integral imaging is a technique capable of displaying 3–D images with continuous parallax in full natural color. It is one of the most promising methods for producing smooth 3–D images. Extracting depth information from integral image has various applications ranging from remote inspection, robotic vision, medical imaging, virtual reality, to content-based image coding and manipulation for integral imaging based 3–D TV. This paper presents a method of generating a depth map from unidirectional integral images through viewpoint image extraction and using a hybrid disparity analysis algorithm combining multi-baseline, neighbourhood constraint and relaxation strategies. It is shown that a depth map having few areas of uncertainty can be obtained from both computer and photographically generated integral images using this approach. The acceptable depth maps can be achieved from photographic captured integral images containing complicated object scene

Weak-wave advancement in nearly collinear four-wave mixing

We identify a new four-wave mixing process in which two nearly collinear pump beams produce phase-dependent gain into a weak bisector signal beam in a self-defocusing Kerr medium. Phase matching is achieved by weak-wave advancement caused by cross-phase modulation between the pump and signal beams. We relate this process to the inverse of spatial modulational instability and suggest a time-domain analog.Comment: 7 pages, 3 figure

Team Cognitive Ability as a Predictor of Team Performance

This manuscript presents two studies of the relationship between team cognitive ability (average Scholastic Aptitude Test score of team members) and team performance (a subjective coach\u27s evaluation and an objective measure using Sagarin\u27s Power Rankings) among NCAA Division 1 Men\u27s Basketball teams. Study 1 was conducted following the 1991-92 season whereas Study 2 was conducted during the 1993-94 season. Both studies indicated that team cognitive ability was significantly related to the coach\u27s evaluation but not to the power ranking measure, and that team strategy moderated the relationship between cognitive ability and the coach\u27s evaluation of performance. Cognitive ability moderated the relationship between team strategy and power ranking, but the nature of the interaction was different across the two studies

Strategy, Core Competence and HR Involvement as Determinants of HR Effectiveness and Refinery Performance

This study examined the impact strategy, core competence, and involvement of HR executives in strategic decision making on the refinery managers\u27 evaluation of the effectiveness of HR and refinery performance among 86 U.S. petro-chemical refineries. Survey results indicated that higher involvement of HR in organizational strategy was strongly related to perceptions of HR effectiveness, and that the relationship was strongest to the extent that refineries pursued a product innovation strategy and viewed skilled employees as their core competence. HR involvement was unrelated to refinery performance, but was actually negatively related to the extent that refineries emphasized efficient production as their core competence

The Role of Human Resource Practices in Petro-Chemical Refinery Performance

This study examined the impact of Human Resource (HR) practices (selection, training, compensation, and appraisal) and participation on the financial performance of U.S. petrochemical refineries. Survey results from HR and Operations respondents indicated that appraisal and training were significantly related to workforce skills and that training and compensation were marginally related to workforce motivation. In addition, only training was significantly related to refinery performance, although the relationship was negative. However, selection, compensation, and appraisal interacted with participation in determining refinery financial performance such that each of these practices were strongly positively related to financial performance only under highly participative systems. Implications are discussed

Photonic crystal polarizers and polarizing beam splitters

We have experimentally demonstrated polarizers and polarizing beam splitters based on microwave-scale two-dimensional photonic crystals. Using polarized microwaves within certain frequency bands, we have observed a squared-sinusoid (Malus) transmission law when using the photonic crystal as a polarizer. The photonic crystal also functions as a polarizing beamsplitter; in this configuration it can be engineered to split incident polarizations in either order, making it more versatile than conventional, Brewster-angle beamsplitters.Comment: 7 pages, 3 figures, published Journal Applied Physics 93, 9429 (2003