Thermal and albedo mapping of the north and south polar regions of Mars

The first maps of the thermal properties of the north and south polar region of Mars are presented. The maps complete the mapping of the entire planet. The maps for the north polar region were derived from Viking Infrared Thermal Mapper (IRTM) observations obtained from 10 Jun. to 30 Sep. 1978. This period corresponds to the early summer season in the north, when the north residual water ice cap was exposed, and the polar surface temperatures were near their maximum. The maps in the south were derived from observations obtained between 24 Aug. to 23 Sep. 1977. This period corresponds to the late summer season in the south, when the seasonal polar cap had retreated to close to its residual configuration, and the second global dust storm of 1977 had largely subsided. The major results concerning the following topics are summarized: (1) surface water ice; (2) polar dune material; and (3) dust deposits

THE EFFECTS OF MARKER SIZE ON THE ACCURACY OF THE ARlEL PERFORMANCEANALYSIS SYSTEM (APASTM)

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THE EFFECTS OF MARKER SIZE ON THE ACCURACY OF THE ARlEL PERFORMANCEANALYSIS SYSTEM (APAStm)

INTRODUCTION In order to increase the efficiency of today's motion analysis systems, most systems are capable of auto digization. In order for the APAS system to auto digitize, retroreflective markers must be used for accurate tracing of the movement. During auto digization, the computer's software will search a given area for pixels that are above a pre-determined light threshold. From these threshold pixels, the software will calculate the center of the marker. To increase the accuracy of the measurements, it has been suggested that the larger the marker, the more accurate the measurement. The purpose of this study was to examine the effects of marker size on the accuracy of the APAS system. METHODS Eight retroreflective markers were placed upon an inverted T-shaped pendulum. Tbelve reference angles were calculated from these markers. Four different starting positions were used (static, a 45 deg, a 90 deg, and a 120 deg. release position) while using four different marker sizes (0.45,0.95, 1.27, and 1.91 cm.) for a total of 16 different conditions. Ten trials were done for each condition. Tbenty frames were auto-digitized from each trial. Frame 10 represented the low point of the trajectory for the dynamic conditions. Deviations were calculated by taking the average angle over the 20 frames and subtracting it from the reference angle. The data was analyzed using a Mixed Effects ANOVA. Inter-trial variability was determined by subtracting the reconstructed angle from the reference angle on a frame by frame basis. RESULTS Significance was found in the ANOVA of marker [F (3,1893) = 6.39, p < 0.00031 and position [F (3,1893) = 350.41, p < 0.00011. Contrast tests indicate that markers 1-3 were all statistically different from marker 4 (p < 0.001, p < 0.0003, p < 0.0106). The least square means of marker showed that as the marker size increased the deviation on average decreased (0.4339 deg. to 0.3883 deg.). Examination of the inter-trial variability showed that the variability increased from the static position up to the 120 deg. position. CONCLUSION Marker size was shown to have a significant effect upon the accuracy of the APAS system. Examination of the least square means seems to indicate that the smallest marker size had the most error and the largest marker size had the least error. It should be noted though that regardless of marker size the error was no greater than 0.5 degrees. For most motion analysis procedures an error of this magnitude is probably an acceptable error

Progress report on the ultra heavy cosmic ray experiment (AO178)

The Ultra Heavy Cosmic Ray Experiment (UHCRE) is based on a modular array of 192 side-viewing solid state nuclear track detector stacks. These stacks were mounted in sets of four in 48 pressure vessels employing sixteen peripheral Long Duration Exposure Facility (LDEF) trays. The extended duration of the LDEF mission has resulted in a greatly enhanced scientific yield from the UHCRE. The geometry factor for high energy cosmic ray nuclei, allowing for Earth shadowing, was 30 sq m-sr, giving a total exposure factor of 170 sq m-sr-y at an orbital inclination of 28.4 degrees. Scanning results indicate that about 3000 cosmic ray nuclei in the charge region with Z greater than 65 were collected. This sample is more than ten times the current world data in the field (taken to be the data set from the HEAO-3 mission plus that from the Ariel-6 mission) and is sufficient to provide the world's first statistically significant sample of actinide (Z greater than 88) cosmic rays. Results to date are presented including details of ultra-heavy cosmic ray nuclei, analysis of pre-flight and post-flight calibration events and details of track response in the context of detector temperature history. The integrated effect of all temperature and age related latent track variations cause a maximum charge shift of +/- 0.8 e for uranium and +/- 0.6 e for the platinum-lead group. The precision of charge assignment as a function of energy is derived and evidence for remarkably good charge resolution achieved in the UHCRE is considered. Astrophysical implications of the UHCRE charge spectrum are discussed

The LDEF ultra heavy cosmic ray experiment

The LDEF Ultra Heavy Cosmic Ray Experiment (UHCRE) used 16 side viewing LDEF trays giving a total geometry factor for high energy cosmic rays of 30 sq m sr. The total exposure factor was 170 sq m sr y. The experiment is based on a modular array of 192 solid state nuclear track detector stacks, mounted in sets of four in 48 pressure vessels. The extended duration of the LDEF mission has resulted in a greatly enhanced potential scientific yield from the UHCRE. Initial scanning results indicate that at least 1800 cosmic ray nuclei with Z greater than 65 were collected, including the world's first statistically significant sample of actinides. Post flight work to date and the current status of the experiment are reviewed

Comparing the Use of Visual Analogue Scales and Likert-type Scales in International Agricultural and Extension Education Surveys

Data collected using survey methodology is readily used to provide insight into improving international agricultural and extension education programs. The evolution of survey technology has allowed educators access to a growing number of audiences; however, the escalating quantity of surveys contributes to greater survey fatigue. Utilizing multiple forms of response, such as Likert-type scales and visual analog scales, may relieve some symptoms of survey fatigue. The use of visual analog scales may allow respondents the ability to respond more freely to questions where fractional differences can hold a wealth of information. This study examined the possible advantages of utilizing visual analog scales rather than Likert-type scales in surveys. A Web-based survey was conducted with respondents randomly assigned to one of two treatments: comparison constructs in traditional Likert-type scale presentation form using radio buttons or comparison constructs with a Visual Analog Scale presentation. Results indicated responses from visual analog scales were similar to those on Likert-type scale questions. No significant additional time to complete the constructs was found; however, a significantly lower non-response rate existed for one construct using the Likert-type scale (10% compared to 32%). Seventy-five percent of the respondents given visual analog scales utilized the freedom to select increments between the restricted points of radio buttons

A New Smartphone-Based Optic Nerve Head Biometric for Verification and Change Detection

Purpose: Lens adapted smartphones are being used regularly instead of ophthalmoscopes. The most common causes of preventable blindness in the world, which are glaucoma and diabetic retinopathy, can develop asymptomatic changes to the optic nerve head (ONH) especially in the developing world where there is a dire shortage of ophthalmologists but ubiquitous mobile phones. We developed a proof-of-concept ONH biometric (application [APP]) to use as a routine biometric on a mobile phone. The unique blood vessel pattern is verified if it maps on to a previously enrolled image. Methods: The iKey APP platform comprises three deep neural networks (DNNs) developed from anonymous ONH images: the graticule blood vessel (GBV) and the blood vessel specific feature (BVSF) DNNs were trained on unique blood vessel vectors. A non-feature specific (NFS) baseline ResNet50 DNN was trained for comparison. Results: Verification reached an accuracy of 97.06% with BVSF, 87.24% with GBV and 79.8% using NFS. Conclusions: A new ONH biometric was developed with a hybrid platform of ONH algorithms for use as a verification biometric on a smartphone. Failure to verify will alert the user to possible changes to the image, so that silent changes may be observed before sight threatening disease progresses. The APP retains a history of all ONH images. Future longitudinal analysis will explore the impact of ONH changes to the iKey biometric platform. Translational Relevance: Phones with iKey will host ONH images for biometric protection of both health and financial data. The ONH may be used for automatic screening by new disease detection DNNs

Early results from the ultra heavy cosmic ray experiment

Data extraction and analysis of the LDEF Ultra Heavy Cosmic Ray Experiment is continuing. Almost twice the pre LDEF world sample has been investigated and some details of the charge spectrum in the region from Z approximately 70 up to and including the actinides are presented. The early results indicate r process enhancement over solar system source abundances

The extreme melt across the Greenland ice sheet in 2012

The discovery of the 2012 extreme melt event across almost the entire surface of the Greenland ice sheet is presented. Data from three different satellite sensors – including the Oceansat-2 scatterometer, the Moderate-resolution Imaging Spectroradiometer, and the Special Sensor Microwave Imager/Sounder – are combined to obtain composite melt maps, representing the most complete melt conditions detectable across the ice sheet. Satellite observations reveal that melt occurred at or near the surface of the Greenland ice sheet across 98.6% of its entire extent on 12 July 2012, including the usually cold polar areas at high altitudes like Summit in the dry snow facies of the ice sheet. This melt event coincided with an anomalous ridge of warm air that became stagnant over Greenland. As seen in melt occurrences from multiple ice core records at Summit reported in the published literature, such a melt event is rare with the last significant one occurring in 1889 and the next previous one around seven centuries earlier in the Medieval Warm Period. Given its rarity, the 2012 extreme melt across Greenland provides an exceptional opportunity for new studies in broad interdisciplinary geophysical research