Accurate 3-D Morphological Measurement Using a Structured-Light Range Sensor

A single-plane structured light range-sensor was tested to establish its usefulness in acquiring 3-D measurements of fish skulls. Twenty-one distances among 22 landmark points for each of 12 neurocrania of the scorpaenid fish Neomerinthe hemingway were taken with digital calipers, with a video-based 2-D imaging system widely used in systematic studies, and with a single-plane structured-light range sensor of inexpensive and simple design. Measures taken by 3-D sensor are highly correlated with those obtained from caliper measurement (r = 0.9995, P \u3c\u3c 0.001 ), with a precision ranging from 0.08–0.43 mm. Like caliper-based measurements, they are less strongly correlated with measurements derived from projected video-imaging. Most skulls were scanned in just over 3 minutes each. Range maps, typically establishing the (x,y,z) coordinates of more than 75,000 points per scan, can be obtained in about 40–50 CPU seconds using software running on multiple platforms. Sensor data taken from different views can be merged to build a more complete 3-D reconstruction. System design, calibration, and use are discussed. By eliminating error due to perspective effects inherent in measuring from projected video images, such sensors hold considerable promise in quantifying biological shape in 3-D for comparative and functional studies

Crude Protein of Hybrid Corn Varieties Evaluated in the Kentucky Hybrid Corn Performance Tests from 1990 to 1993

Grain samples have been collected each year since 1990 from three locations of the Kentucky Hybrid Corn Performance Test and analyzed for crude protein. The objective was to provide an unbiased comparative evaluation of the crude protein content of corn hybrids sold in Kentucky. The results indicate that while management and environment at each test 1ocat i on may have significant influences, crude protein does differ among hybrid genotypes. The feeding value of specific hybrid genotypes based on their protein content may have significant influence in diet formulation for non-ruminant animals owing to the amount of supplement needed to properly balance the diet, and may be an important economic factor in animal production. Previous summaries of annual results have been published. Only crude protein data are included in this report and are summarized over locations in a year and as multiple year summaries

Comparison of Ocular Outcomes in Two 14-Day Bed Rest Studies

Reports of astronauts' visual changes have raised concern about ocular health during long-duration spaceflight. Some of these findings include globe flattening with hyperopic shifts, choroidal folds, optic disc edema, retinal nerve fiber layer (RNFL) thickening, and cotton wool spots. While the etiology remains unknown, it is hypothesized that, in predisposed individuals, hypertension in the brain may follow cephalad fluid shifts during spaceflight. This possible mechanism of ocular changes may also apply to analogous cases of idiopathic intracranial hypertension (IIH) or pseudotumor cerebri on Earth patients. Head-down t ilt (HDT) bed rest is a spaceflight analog that induces cephalad fluid shifts. Previous studies of the HDT position demonstrated body fluid shifts associated with changes in intraocular pressure (IOP) but the conditions of bed rest varied among experiments, making it difficult to compare data and draw conclusions. For these reasons, vision evaluation of bed rest subjects was implemented for NASA bed rest studies since 2010, in an attempt to monitor vision health in subjects subjected to bed rest. Vision monitoring is thus currently performed in all NASA-conducted bed rest campaign

Long Duration Head-Down Tilt Bed Rest Studies: Safety Considerations Regarding Vision Health

Visual symptoms reported in astronauts returning from long duration missions in low Earth orbit, including hyperopic shift, choroidal folds, globe flattening and papilledema, are thought to be related to fluid shifts within the body due to microgravity exposure. Because of this possible relation to fluid shifts, safety considerations have been raised regarding the ocular health of head-down tilt (HDT) bed rest subjects. HDT is a widely used ground ]based analog that simulates physiological changes of spaceflight, including fluid shifts. Thus, vision monitoring has been performed in bed rest subjects in order to evaluate the safety of HDT with respect to vision health. Here we report ocular outcomes in 9 healthy subjects (age range: 27-48 years; Male/Female ratio: 8/1) completing bed rest Campaign 11, an integrated, multidisciplinary 70-day 6 degrees HDT bed rest study. Vision examinations were performed on a weekly basis, and consisted of office-based (2 pre- and 2 post-bed rest) and in-bed testing. The experimental design was a repeated measures design, with measurements for both eyes taken for each subject at each planned time point. Findings for the following tests were all reported as normal in each testing session for every subject: modified Amsler grid, red dot test, confrontational visual fields, color vision and fundus photography. Overall, no statistically significant differences were observed for any of the measures, except for both near and far visual acuity, which increased during the course of the study. This difference is not considered clinically relevant as may result from the effect of learning. Intraocular pressure results suggest a small increase at the beginning of the bed rest phase (p=0.059) and lesser increase at post-bed rest with respect to baseline (p=0.046). These preliminary results provide the basis for further analyses that will include correlations between intraocular pressure change pre- and post-bed rest, and optical coherence tomography measurements of the retina

Association Between Cardiovascular and Intraocular Pressure Changes in a 14-day 6 deg Head Down Tilt (HDT) Bed Rest Study: Possible Implications in Retinal Anatomy

Mean IOP significantly increased while at 6deg HDT and returned towards pre-bed rest values upon leaving bed rest. While mean IOP increased during bed rest, it remained within the normal limits for subject safety. A diuretic shift and cardiovascular deconditioning occurs during in-bed rest, as expected. There was no demonstrable correlation between the largest change in IOP (pre/post) and cardiovascular measure changes (pre/post). Additional mixed effects linear regression modeling may reveal some subclinical physiological changes that might assist in describing the VIIP syndrome pathophysiology

70 Days of 6 Degrees-head Down Tilt Bed Rest and its Impact on Ocular Parameters

No abstract availabl

Comparison of Structural and Functional Ocular Outcomes Between 14- and 70-Day Bed Rest

To compare structural and functional ocular outcomes between14-and 70-day HDTBR in healthy human subjects

Ocular Outcomes Comparison Between 14- and 70-day Head-down Tilt Bed Rest

No abstract availabl

Vision Monitoring of Head-Down Tilt Bed Rest Subjects

No abstract availabl

Characterization of Knots and Links Arising From Site-specific Recombination on Twist Knots

We develop a model characterizing all possible knots and links arising from recombination starting with a twist knot substrate, extending previous work of Buck and Flapan. We show that all knot or link products fall into three well-understood families of knots and links, and prove that given a positive integer $n$, the number of product knots and links with minimal crossing number equal to $n$ grows proportionally to $n^5$. In the (common) case of twist knot substrates whose products have minimal crossing number one more than the substrate, we prove that the types of products are tightly prescribed. Finally, we give two simple examples to illustrate how this model can help determine previously uncharacterized experimental data.Comment: 32 pages, 7 tables, 27 figures, revised: figures re-arranged, and minor corrections. To appear in Journal of Physics