Satellite radar altimetry over ice. Volume 1: Processing and corrections of Seasat data over Greenland

The data-processing methods and ice data products derived from Seasat radar altimeter measurements over the Greenland ice sheet and surrounding sea ice are documented. The corrections derived and applied to the Seasat radar altimeter data over ice are described in detail, including the editing and retracking algorithm to correct for height errors caused by lags in the automatic range tracking circuit. The methods for radial adjustment of the orbits and estimation of the slope-induced errors are given

Satellite radar altimetry over ice. Volume 4: Users' guide for Antarctica elevation data from Seasat

A gridded surface-elevation data set and a geo-referenced data base for the Seasat radar altimeter data over Greenland are described. This is a user guide to accompany the data provided to data centers and other users. The grid points are on a polar stereographic projection with a nominal spacing of 20 km. The gridded elevations are derived from the elevation data in the geo-referenced data base by a weighted fitting of a surface in the neighborhood of each grid point. The gridded elevations are useful for the creating of large-scale contour maps, and the geo-referenced data base is useful for regridding, creating smaller-scale contour maps, and examinating individual elevation measurements in specific geographic areas. Tape formats are described, and a FORTRAN program for reading the data tape is listed and provided on the tape

Satellite radar altimetry over ice. Volume 2: Users' guide for Greenland elevation data from Seasat

A gridded surface-elevation data set and a geo-referenced data base for the Seasat radar altimeter data over Antarctica are described. It is intended to be a user's guide to accompany the data provided to data centers and other users. The grid points are on a polar stereographic projection with a nominal spacing of 20 km. The gridded elevations are derived from the elevation data in the geo-referenced data base by a weighted fitting of a surface in the neighborhood of each grid point. The gridded elevations are useful for the creating smaller-scale contour maps, and examining individual elevation measurements in specific geographic areas. Tape formats are described, and a FORTRAN program for reading the data tape is listed and provided on the tape

Performance and Safety of Lithium-ion Capacitors

Lithium-ion capacitors (LIC) are a recent innovation in the area of supercapacitors and ultracapacitors. With an operating voltage range similar to that of lithium-ion batteries and a very low selfdischarge rate, these can be readily used in the place of batteries especially when large currents are required to be stored safely for use at a later time

Recycling the Central City: The Development of a New Town-In Town.

In 1978 author Martin presented a detailed examination of the planning and development of Minneapolis' Cedar-Riverside project, the first federally sponsored new town. Her study includes the origins of the project through the first phase of development, along with a survey conducted after the first year of occupancy. Illustrated with many maps and photographs

Retinal oscillations carry visual information to cortex

Thalamic relay cells fire action potentials that transmit information from retina to cortex. The amount of information that spike trains encode is usually estimated from the precision of spike timing with respect to the stimulus. Sensory input, however, is only one factor that influences neural activity. For example, intrinsic dynamics, such as oscillations of networks of neurons, also modulate firing pattern. Here, we asked if retinal oscillations might help to convey information to neurons downstream. Specifically, we made whole-cell recordings from relay cells to reveal retinal inputs (EPSPs) and thalamic outputs (spikes) and analyzed these events with information theory. Our results show that thalamic spike trains operate as two multiplexed channels. One channel, which occupies a low frequency band (<30 Hz), is encoded by average firing rate with respect to the stimulus and carries information about local changes in the image over time. The other operates in the gamma frequency band (40-80 Hz) and is encoded by spike time relative to the retinal oscillations. Because these oscillations involve extensive areas of the retina, it is likely that the second channel transmits information about global features of the visual scene. At times, the second channel conveyed even more information than the first.Comment: 21 pages, 10 figures, submitted to Frontiers in Systems Neuroscienc

Assessment of culture and environment in the Adolescent Brain and Cognitive Development Study: Rationale, description of measures, and early data.

Neurodevelopmental maturation takes place in a social environment in addition to a neurobiological one. Characterization of social environmental factors that influence this process is therefore an essential component in developing an accurate model of adolescent brain and neurocognitive development, as well as susceptibility to change with the use of marijuana and other drugs. The creation of the Culture and Environment (CE) measurement component of the ABCD protocol was guided by this understanding. Three areas were identified by the CE Work Group as central to this process: influences relating to CE Group membership, influences created by the proximal social environment, influences stemming from social interactions. Eleven measures assess these influences, and by time of publication, will have been administered to well over 7,000 9-10 year-old children and one of their parents. Our report presents baseline data on psychometric characteristics (mean, standard deviation, range, skewness, coefficient alpha) of all measures within the battery. Effectiveness of the battery in differentiating 9-10 year olds who were classified as at higher and lower risk for marijuana use in adolescence was also evaluated. Psychometric characteristics on all measures were good to excellent; higher vs. lower risk contrasts were significant in areas where risk differentiation would be anticipated

A Puzzle Involving Galactic Bulge Microlensing Events

We study a sample of 16 microlensed Galactic bulge main sequence turnoff region stars for which high dispersion spectra have been obtained with detailed abundance analyses. We demonstrate that there is a very strong and highly statistically significant correlation between the maximum magnification of the microlensed bulge star and the value of the [Fe/H] deduced from the high resolution spectrum of each object. Physics demands that this correlation, assuming it to be real, be the result of some sample bias. We suggest several possible explanations, but are forced to reject them all,and are left puzzled. To obtain a reliable metallicity distribution in the Galactic bulge based on microlensed dwarf stars it will be necessary to resolve this issue through the course of additional observations.Comment: Submitted to ApJL, table 2 (quite long) will only appear in the on-line version of ApJ

Psychosocial factors influencing contraceptive use among adolescent mothers in the Volta Region of Ghana: application of the Health Belief Model

Background: Globally, complications arising from pregnancy and childbirth are the leading cause of death among pregnant women aged 15 to 19 years. This study investigated the psychosocial factors influencing contraceptive use among adolescentmothers in the Volta Region using the Health Belief Model (HBM).Methods: This was a cross-sectional study conducted among 422 adolescent mothers. An interviewer-administered structured questionnaire was used to collect data. Binary logistic regression was used to determine the strength of association between the independent and the dependent variables at a p-value less than 0.05.Results: The prevalence of contraceptive use was 18.7%. Concerning perceived susceptibility, there was a significant association between contraceptive use and the perception of being at risk of pregnancy complications (p&lt;0.001). Perceived barriers showed a significant association between fear of side-effects of contraceptives and contraceptive use (p=0.007). Concerning perceived self-efficacy, there was a significant association between contraceptive use and confidence to suggest to a partner to use contraceptives (p=0.003); confidence to ask for contraceptives from health facilities (p&lt;0.001) and confidence to use contraceptives (p&lt;0.001).Conclusion: Programmes to increase contraceptive use should aim at heightening the perception of risk of pregnancy complications, reduce barriers to contraceptive use and increase the skills in negotiating contraceptive use. Keywords: Contraceptive use; Adolescent mothers; Health Belief Model; Volta Region; Ghana

Past Choices/Present Landscapes: The Impact of Urban Renewal on the Twin Cities.

Urban renewal was designed to clean up and rebuild our deteriorating American cities. In the 1950s clearance and new construction were emphasized. In the 1960s attention turned to rehabilitation. By 1989 the program was mostly forgotten, but it left an indelible mark on the landscapes of the cities. Martin and Goddard trace the history of urban renewal in Minneapolis and St. Paul, looking at both downtown and neighborhood projects. They document the social and political processes that guided local renewal decisions, demonstrating that urban renewal in the Twin Cities was substantially different from elsewhere