Interactive 3-D Visualization: A tool for seafloor navigation, exploration, and engineering

Recent years have seen remarkable advances in sonar technology, positioning capabilities, and computer processing power that have revolutionized the way we image the seafloor. The massive amounts of data produced by these systems present many challenges but also offer tremendous opportunities in terms of visualization and analysis. We have developed a suite of interactive 3-D visualization and exploration tools specifically designed to facilitate the interpretation and analysis of very large (10\u27s to 100\u27s of megabytes), complex, multi-component spatial data sets. If properly georeferenced and treated, these complex data sets can be presented in a natural and intuitive manner that allows the integration of multiple components each at their inherent level of resolution and without compromising the quantitative nature of the data. Artificial sun-illumination, shading, and 3-D rendering can be used with digital bathymetric data (DTM\u27s) to form natural looking and easily interpretable, yet quantitative, landscapes. Color can be used to represent depth or other parameters (like backscatter or sediment properties) which can be draped over the DTM, or high resolution imagery can be texture mapped on bathymetric data. When combined with interactive analytical tools, this environment has facilitated the use of multibeam sonar and other data sets in a range of geologic, environmental, fisheries, and engineering applications

Enterprise Budgets for Livestock Businesses that Use National Forest Grazing Land

Cow-calf and sheep enterprise inputs, production, costs, and returns are estimated for ranches with Forest Service grazing permits using 1982 as a base year. Budgets represent different cow and sheep herd sizes in National Forests and national Grasslands of United States.Beef cows, sheep costs and returns, Federal rangeland, Livestock Production/Industries,

Magnetic alteration of zero-age oceanic basalt

The youngest sampled submarine lava flow, which erupted June 1993 on the Juan de Fuca Ridge, provides the basis for a tight constraint on the initial or zero-age magnetization state of MORB. Detailed profiles of magnetic hysteresis parameters, Curie temperatures, and unblocking temperatures of NRM with respect to the chilled margin of a pillow fragment show evidence of significant oxidation, which preferentially affected the finest grain-size fraction and principal remanence carrier of the titanomagnetite magnetic mineralogy. The oxidation must have occurred during or immediately after initial cooling, implying that MORB is already appreciably magnetically altered before aging. Nevertheless, successful results of Thellier paleointensity experiments on the basalt sample lend support to the idea that crustal magnetization represented by MORB preserves a record of geomagnetic intensity variations that may be reflected in small-scale magnetic anomalies

Magnetic hysteresis in young mid“ocean ridge basalts: Dominant cubic anisotropy?

Magnetic hysteresis data from young mid“ocean ridge basalts include samples with saturation remanence to saturation magnetization (Mrs/Ms) ratios greater than 0.5, the theoretical limit for an assemblage of single domain grains with uniaxial anisotropy. Under the usual assumption of dominant uniaxial anisotropy, the narrow single domain grain size distribution implied by these high Mrs/Ms values is difficult to reconcile with petrographic and remanence data that suggest the presence of larger multidomain grains. Dominant cubic anisotropy provides a plausible explanation for the high Mrs/Ms ratios, and if generally valid, requires reinterpretation of granulometric and domain state inferences made from hysteresis data

Magnetic telechemistry and magmatic segmentation on the Southern East Pacific Rise

Results from axial dredges and a profile inversion of magnetic anomaly data along the axis of the East Pacific Rise (EPR) at 13-23°S provide an estimate of the average degree of fractionation for the extrusive layer at this ultrafast-spreading (∼145 mm/yr full rate) ridge. We find a high correlation (R=0.81) between dredge mean FeO* (total iron as FeO) and natural remanence for 34 axial dredges with multiple samples having coincident geochemical and magnetic data. We attribute this good correlation to detailed sampling spanning the full range of cooling-related magnetization changes within a flow and to the young age (0-6 ka) of these axial samples, which effectively minimizes time-dependent magnetization changes due to geomagnetic intensity or alteration. A composite axial magnetic anomaly profile shows large amplitude (up to 400 nT) fluctuations with wavelengths of 50-200 km, which theoretical considerations suggest can reliably be related to the magnetization directly beneath the ship. For much of the southern EPR, seismic data provide independent limits on the axial thickness (259 ± 55 m) and the pattern of off-axis thickening of the extrusive magnetic source layer. These data also provide evidence for an axial magma lens that effectively eliminates anomaly contributions from deeper magnetic sources. Inversion of the axial magnetic anomaly data utilizing these geophysical constraints yields a magnetization solution which, through use of the regression relating FeO* and natural remanence, may be related to the average degree of differentiation of the extrusive source layer. The magnetic data reveal a pattern of magmatic segmentation that closely parallels the tectonic segmentation of the ridge, suggesting that magma supply may be an important control on the average degree of differentiation of the extrusive layer

Variations in layer 2A thickness and the origin of the central anomaly magnetic high

The seismically determined off-axis thickening of the extrusive layer is apparently at odds with the magnetic anomaly high typically associated with the ridge crest. The positive magnetization contrast at the ridge crest is most likely caused by rapid alteration of the extrusive source layer which occurs over spatial scales (2-3 km) comparable to that of the proposed Layer 2A thickening. We present magnetic remanence data from basalts dredged on and near the East Pacific Rise axis at 12°N which are compatible with a rapid magnetization reduction (~20 k.y. to decay to 1/e). Together with near bottom magnetic profiles from the ultra-fast-spreading East Pacific Rise at 19.5°S, these data suggest that previous estimates of the time constant of alteration inferred from slow-spreading ridges (0.5 m.y.) may be more than an order of magnitude too high

Calibration of magnetic granulometric trends in oceanic basalts

The validity of magnetic granulometric estimates relies heavily on the ability to distinguish ultrafine particles from coarser grains. For example, populations with dominantly superparamagnetic (SP) or multidomain (MD) grains both are characterized by low remanence and coercivity, and distinguishing these endmembers may provide valuable clues to the origin of magnetization in the intervening stable single domain (SD) size range. The natural grain size variations associated with variable cooling rates in submarine lavas provide a rare opportunity for examining progressive changes in average magnetic grain size, from SP–SD mixtures in submarine basaltic glass to SD–MD mixtures in flow interiors. Based on microanalysis and rock magnetic measurements on pillow basalt samples dredged from the flanks of the Mid-Atlantic Ridge (ages < 1 Ma to 70 Ma), a model of preferential dissolution with time of the finest-grained titanomagnetites has recently been suggested as the major process contributing to long-term temporal changes in remanent intensity of mid-ocean ridge basalts. We evaluated the local and long-term temporal trends in effective magnetic grain size predicted by this model using hysteresis data from a large number of submarine basalt samples which span a range of ages from ∼0 to ∼122 Ma. Specimens were systematically taken along transects perpendicular to the chilled margin of each sample. The large number of data (∼750 loops) and the inferred progressive change in grain size approaching the chilled margin allow recognition of mixing trends between MD and SD grains and between SD and SP grains on a Day-plot. These trends in hysteresis parameters are crucial to resolving the inherent, but frequently overlooked, ambiguity in inferring grain size from hysteresis parameters. We illustrate that two additional rock magnetic tests (warming of a low-temperature isothermal remanence and hysteresis loop shapes) often used to address these ambiguities are inconclusive, requiring some independent knowledge of whether SP or MD grains are likely to be present. Even with a considerably larger data set the substantial intrasample variability in oceanic basalts precludes recognition of any systematic trend in magnetic grain size with age

Vitamin D deficiency: awareness and practice

Within the UK rickets is emerging as a national public health issue, particularly among at-risk groups. There is concern that health professionals are overlooking recommendations for vitamin supplementation and opportunities for prevention. This paper reports on a study that aimed to identify current knowledge and practice regarding vitamin D deficiency and supplementation among community midwifery and health visiting teams employed in one NHS trust. A questionnaire was distributed to all health visiting and community midwifery team members (n=96), with a 76% response rate (n=73). Results suggest varying levels of awareness about vitamin D deficiency and groups at increased risk. Only 52% reported that they were aware of health department recommendations for vitamin supplementation. Health visiting teams recommended supplements more frequently than community midwives, but overall the recommendations were implemented inconsistently. Participants identified families eligible for the government Healthy Start scheme, but fewer were recommending Healthy Start vitamins. A deeper understanding of vitamin D deficiency and health department recommendations for vitamin supplementation is required by health professionals to ensure families are advised about appropriate prevention messages and to implement recommendations effectively. Key words: Vitamin D deficiency, rickets, Healthy Start, vitamin supplements, health departmen

The Value of Literacy Practices

The concepts of literacy events and practices have received considerable attention in educational research and policy. In comparison, the question of value, that is, ‘which literacy practices do people most value?’ has been neglected. With the current trend of cross-cultural adult literacy assessment, it is increasingly important to recognise locally valued literacy practices. In this paper we argue that measuring preferences and weighting of literacy practices provides an empirical and democratic basis for decisions in literacy assessment and curriculum development and could inform rapid educational adaptation to changes in the literacy environment. The paper examines the methodological basis for investigating literacy values and its potential to inform cross-cultural literacy assessments. The argument is illustrated with primary data from Mozambique. The correlation between individual values and respondents’ socio-economic and demographic characteristics is explored

Computational Non-Destructive Evaluation Improving Ultrasonic Interrogation of Complex Geometry Composite Parts

Finite element simulation was employed in modeling the ultrasound (UT) pressure pulse propagation through a coupled liquid-composite medium to reproduce experimental data. From the simulation point of view, the proposed approach is challenging when there is a large simulation domain. For example, it is shown that a sub-micron wavelength of an ultrasonic wave requires a mesh size of several microns and this in turn requires significant computational resources, as well as special care in modeling. Some of the simulation results are presented considering that such modeling should reproduce experimental data for a healthy and faulty composite structure with complex geometry. Many possible experimental setups are simulated to demonstrate the non-destructive testing technique. This setup includes the generation of pressure pulse propagating through the tested composite plate and possible scattering by discontinuities (area of different impedance) that may be present in the panel. This scattered pulse together with the baseline pressure pulse generates a signature on the probe element which can be used to locate the position of defects in the structures