2,219 research outputs found

    Marine Neogene Samples from around Tasmania: an extension to the Miocene/Pliocene marine record in Tasmania

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    New Miocene and Quaternary foraminiferid faunas have been recovered from previously unrecorded localities onshore near Penguin and Strahan, and at nine offshore localities off northwestern, northeastern and southeastern Tasmania. Most Miocene benthic forms found in these samples are well known from other Tasmanian Tertiary sections but a few previously unreported taxa are recorded in Tasmania for the first time. Two samples from off northeastern Tasmania are Miocene. The sample from southeastern Tasmania is Early Miocene with Quaternary overlying it. Pebbles from Ocean Beach, north of Strahan, contain earliest Middle Miocene faunas. Other samples from off northeastern and northwestern Tasmania contain Quaternary faunas which probably reflect both periods of lower sea level and cool water and also periods of higher sea level and warmer water. These samples extend the range of Miocene calcareous sediments much farther south on both west and east coasts of Tasmania. They also reinforce the pattern of Tasmanian Neogene sedimentation cycles (earliest Early Miocene, latest Early-earliest Middle Miocene, midLate Pliocene) identified previously

    Virtually optimized insoles for offloading the diabetic foot: a randomized crossover study

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    Integration of objective biomechanical measures of foot function into the design process for insoles has been shown to provide enhanced plantar tissue protection for individuals at-risk of plantar ulceration. The use of virtual simulations utilizing numerical modeling techniques offers a potential approach to further optimize these devices. In a patient population at-risk of foot ulceration, we aimed to compare the pressure offloading performance of insoles that were optimized via numerical simulation techniques against shape-based devices. Twenty participants with diabetes and at-risk feet were enrolled in this study. Three pairs of personalized insoles: one based on shape data and subsequently manufactured via direct milling; and two were based on a design derived from shape, pressure, and ultrasound data which underwent a finite element analysis-based virtual optimization procedure. For the latter set of insole designs, one pair was manufactured via direct milling, and a second pair was manufactured through 3D printing. The offloading performance of the insoles was analyzed for forefoot regions identified as having elevated plantar pressures. In 88% of the regions of interest, the use of virtually optimized insoles resulted in lower peak plantar pressures compared to the shape-based devices. Overall, the virtually optimized insoles significantly reduced peak pressures by a mean of 41.3 kPa (p < 0.001, 95% CI [31.1, 51.5]) for milled and 40.5 kPa (p < 0.001, 95% CI [26.4, 54.5]) for printed devices compared to shape-based insoles. The integration of virtual optimization into the insole design process resulted in improved offloading performance compared to standard, shape-based devices.Full Tex

    Classifying multispectral data by neural networks

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    Several energy functions for synthesizing neural networks are tested on 2-D synthetic data and on Landsat-4 Thematic Mapper data. These new energy functions, designed specifically for minimizing misclassification error, in some cases yield significant improvements in classification accuracy over the standard least mean squares energy function. In addition to operating on networks with one output unit per class, a new energy function is tested for binary encoded outputs, which result in smaller network sizes. The Thematic Mapper data (four bands were used) is classified on a single pixel basis, to provide a starting benchmark against which further improvements will be measured. Improvements are underway to make use of both subpixel and superpixel (i.e. contextual or neighborhood) information in tile processing. For single pixel classification, the best neural network result is 78.7 percent, compared with 71.7 percent for a classical nearest neighbor classifier. The 78.7 percent result also improves on several earlier neural network results on this data

    The Very Highly Ionized Broad Absorption Line System of the QSO SBS1542+541

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    We have analyzed the broad absorption line system of the bright (V=16.5) high-redshift (z=2.361) QSO SBS1542+541 using UV spectra from the HST FOS along with optical data from the MMT and the Steward Observatory 2.3m telescope. These spectra give continuous wavelength coverage from 1200 to 8000 Angstroms, corresponding to 340 to 2480 Angstroms in the QSO rest frame. This object therefore offers a rare opportunity to study broad absorption lines in the rest-frame extreme UV. We find that the absorption system is dominated by very high-ionization species, including O VI, NeVIII, and SiXII. We also identify apparently saturated broad Lyman-series lines of order Ly-gamma and higher. There is strong evidence for partial occultation of the QSO emission source, particularly from the higher-order Lyman lines which indicate a covered fraction less than 0.2. Overall, the data suggest a correlation between a larger covered fraction and a higher state of ionization. We suggest that the different covered fractions can be explained by either a special line of sight through a disk-like geometry or by the existence of density fluctuations of a factor >2 in the BAL gas. Our photoionization models of the system indicate a large column density and high ionization state similar to that found in X-ray ``warm absorbers''.Comment: 31 pages, 13 figures, to be published in Ap

    Highly Ionized Collimated Outflow from HE 0238 - 1904

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    We present a detailed analysis of a highly ionized, multiphased and collimated outflowing gas detected through O V, O VI, Ne VIII and Mg X absorption associated with the QSO HE 0238 - 1904 (z_em ~ 0.629). Based on the similarities in the absorption line profiles and estimated covering fractions, we find that the O VI and Ne VIII absorption trace the same phase of the absorbing gas. Simple photoionization models can reproduce the observed N(Ne VIII), N(O VI) and N(Mg X) from a single phase whereas the low ionization species (e.g. N III, N IV, O IV) originate from a different phase. The measured N(Ne VIII)/N(O VI) ratio is found to be remarkably similar (within a factor of ~ 2) in several individual absorption components kinematically spread over ~ 1800 km/s. Under photoionization this requires a fine tuning between hydrogen density (nH) and the distance of the absorbing gas from the QSO. Alternatively this can also be explained by collisional ionization in hot gas with T > 10^{5.7} K. Long-term stability favors the absorbing gas being located outside the broad line region (BLR). We speculate that the collimated flow of such a hot gas could possibly be triggered by the radio jet interaction.Comment: Minor revision (accepted for publication in MNRAS letter

    Let me Google that for you:a time series analysis of seasonality in internet search trends for terms related to foot and ankle pain

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    BACKGROUND: The analysis of internet search traffic may present the opportunity to gain insights into general trends and patterns in information seeking behaviour related to medical conditions at a population level. For prevalent and widespread problems such as foot and ankle pain, this information has the potential to improve our understanding of seasonality and trends within these conditions and their treatments, and may act as a useful proxy for their true incidence/prevalence characteristics. This study aimed to explore seasonal effects, general trends and relative popularity of internet search terms related to foot and ankle pain over the past decade. METHODS: We used the Google Trends tool to obtain relative search engine traffic for terms relating to foot and ankle pain and common treatments from Google search and affiliated pages for major northern and southern hemisphere English speaking nations. Analysis of overall trends and seasonality including summer/winter differences was carried out on these terms. RESULTS: Searches relating to general foot pain were on average 3.4 times more common than those relating to ankle pain, and twice as common as searches relating to heel pain. Distinct seasonal effects were seen in the northern hemisphere, with large increases in search volumes in the summer months compared to winter for foot (p = 0.004, 95 % CI [22.2–32.1]), ankle (p = 0.0078, 95 % CI [20.9–35.5]), and heel pain (p = 0.004, 95 % CI [29.1–45.6]). These seasonal effects were reflected by data from Australia, with the exception of ankle pain. Annual seasonal effects for treatment options were limited to terms related to foot surgery and ankle orthoses (p = 0.031, 95 % CI [3.5–20.9]; p = 0.004, 95 % CI [7.6–25.2] respectively), again increasing in the summer months. CONCLUSIONS: A number of general trends and annual seasonal effects were found in time series internet search data for terms relating to foot and ankle pain. This data may provide insights into these conditions at population levels. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13047-015-0074-9) contains supplementary material, which is available to authorized users

    Radiative Transfer Effects on the Lya Forest

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    Strong observational evidence for a fluctuating ultraviolet background (UVB) has been accumulating through a number of studies of the HI and HeII Lya forest as well as accurate IGM metallicity measurements. UVB fluctuations could arise both from the inhomogeneous distribution of the ionizing sources and/or from radiative transfer (RT) through the filamentary IGM. In this study we investigate, via numerical simulations, the role of RT effects such as shadowing, self-shielding and filtering of the ionizing radiation, in giving raise to a fluctuating UVB. We focus on possible detectable signatures of these effects on quantities derived from Lya forest spectra, as photoionization rate fluctuations, eta parameter (the HeII to HI column density ratio) distributions and the IGM temperature at redshift about 3. We find that RT induces fluctuations up to 60% in the UVB, which are tightly correlated to the density field. The UVB mean intensity is progressively suppressed toward higher densities and photon energies above 4 Ryd, due to the high HeII opacity. Shielding of overdense regions (Delta > 5) from cosmic HeII ionizing radiation, produces a decreaseing trend of eta with overdensity. Furthermore we find that the mean eta value inferred from HI-HeII Lya forest observations can be explained only by properly accounting for the actual IGM opacity. We outline and discuss several implications of our findings.Comment: 13 pages, 10 figures, Accepted for publication in MNRA
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