2,520 research outputs found

    A Bayesian method to estimate the depth and the range of phonating sperm whales using a single hydrophone

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    Some bioacousticians have used a single hydrophone to calculate the depth/range of phonating diving animals. The standard one-hydrophone localization method uses multipath transmissions (direct path, sea surface, and seafloor reflections) of the animal phonations as a substitute for a vertical hydrophone array. The standard method requires three multipath transmissions per phonation. Bioacousticians who study foraging sperm whales usually do not have the required amount of multipath transmissions. However, they usually detect accurately (using shallow hydrophones towed by research vessels) direct path transmissions and sea surface reflections of sperm whale phonations (clicks). Sperm whales emit a few thousand clicks per foraging dive, therefore researchers have this number of direct path transmissions and this number of sea surface reflections per dive. The author describes a Bayesian method to combine the information contained in those acoustic data plus visual observations. The author’s tests using synthetic data show that the accurate estimation of the depth/range of sperm whales is possible using a single hydrophone and without using any seafloor reflections. This method could be used to study the behavior of sperm whales using a single hydrophone in any location no matter what the depth, the relief, or the constitution of the seafloor might be

    Working with OpenCL to Speed Up a Genetic Programming Financial Forecasting Algorithm: Initial Results

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    The genetic programming tool EDDIE has been shown to be a successful financial forecasting tool, however it has suffered from an increase in execution time as new features have been added. Speed is an important aspect in financial problems, especially in the field of algorithmic trading, where a delay in taking a decision could cost millions. To offset this performance loss, EDDIE has been modified to take advantage of multi-core CPUs and dedicated GPUs. This has been achieved by modifying the candidate solution evaluation to use an OpenCL kernel, allowing the parallel evaluation of solutions. Our computational results have shown improvements in the running time of EDDIE when the evaluation was delegated to the OpenCL kernel running on a multi-core CPU, with speed ups up to 21 times faster than the original EDDIE algorithm. While most previous works in the literature reported significantly improvements in performance when running an OpenCL kernel on a GPU device, we did not observe this in our results. Further investigation revealed that memory copying overheads and branching code in the kernel are potentially causes of the (under-)performance of the OpenCL kernel when running on the GPU device

    Economics of boar taint prevention without surgical castration in the pork chain

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    An economic analyses of boar taint prevention without surgical castration is lacking. This paper explores currently feasible alternatives to surgical castration along the pork chain. The considered alternatives include genetic selection (pig breeding stage); altering management strategies (pig growing stage); slaughter at younger age and lower weight (slaughtering stage). Control measures relevant to these alternatives were designed and examined, using costeffectiveness and cost-benefit analysis. Results show that the option of single-sex raising of entire males is more cost-effective compared to the mixed-sex option. The breeding programs combining selection on boar taint and economics are more cost-effective than programs focusing on boar taint only, and also much more cost-effective than slaughtering at a younger age and lower weigh

    The effects of subcutaneous fat thickness on the production efficiency and organopeltic properties of beef

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    Eighty-four weanling Hereford steers were used in a two-year study of the effects of three pre-determined subcutaneous fat thickness levels on the production efficiency and organoleptic properties of beef. Three rations (low, medium and high energy levels) were fed to produce a fat thickness over the 12th - 13th rib of 5 mm., 8 to 10 mm. and 13 to 15 mm. for the three rations respectively, after a 150 to 185 day feeding period. Average daily gains were 1.18 lb., 1.55 lb. and 2.07 lb. The rate of fat deposition was monitored by ultrasonic means. Carcass conformation grade, marbling score and carcass grade were significantly (P\u3c.01l) increased as level of energy in the ration increased. Higher feeding levels tended to produce brighter colored, firmer, finer textured muscle. Ration had no significant effect on flavor and juiciness scores. A tendency for tenderness to decrease as feeding level increased was observed. Carcasses from steers on the highest energy level had significantly (P\u3c.01) lower tenderness scores and higher shear values. Significant (P \u3c.01) negative relationships were found between tenderness and marbling score (r = -.35) carcans grade (r = -.40) and fat thickness (r = -.41). Ultrasonic estimates of fat thickness and carcass fat thickness were highly related

    Specific gravity of the longissimus dorsl muscle from the 9-10-11 rib section as an objective measure of beef carcass eating quality

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    Specifically the objectives of this study were: 1. To determine if the specific gravity of the longissimus dorsi muscle from the 9-10-11 rib section of the beef carcass can be used as an objective measure of eating quality. 2. To determine if the specific gravity of the longissimus dorsi muscle of the 9-10-11 rib section of the beef carcass can be correlated with physical and chemical determinations of the edible portion of the beef carcass. 3. To determine eating preference among grades of beef by a trained taste panel. 4. To study cooking losses and Warner-Bratzler shear values for tenderness among grades of beef

    Does the geoid drift west?

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    In 1970 Hide and Malin noted a correlation of about 0.8 between the geoid and the geomagnetic potential at the Earth's surface when the latter is rotated eastward in longitude by about 160 degrees and the spherical harmonic expansions of both functions are truncated at degree 4. From a century of magnetic observatory data, Hide and Malin inferred an average magnetic westward drift rate of about 0.27 degrees/year. They attributed the magnetic-gravitational correlation to a core event at about 1350 A.D. which impressed the mantle's gravity pattern at long wavelengths onto the core motion and the resulting magnetic field. The impressed pattern was then carried westward 160 degrees by the nsuing magnetic westward drift. An alternative possibility is some sort of steady physical coupling between the magnetic and gravitational fields (perhaps migration of Hide's bumps on the core-mantle interface). This model predicts that the geoid will drift west at the magnetic rate. On a rigid earth, the resulting changes in sea level would be easily observed, but they could be masked by adjustment of the mantle if it has a shell with viscosity considerably less than 10 to the 21 poise. However, steady westward drift of the geoid also predicts secular changes in g, the local acceleration of gravity, at land stations. These changes are now ruled out by recent independent high-accuracy absolute measurements of g made by several workers at various locations in the Northern Hemisphere

    The scientific case for magnetic field satellites

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    To make full use of modern magnetic data and the paleomagnetic record, we must greatly improve our understanding of how the geodynamo system works. It is clearly nonlinear, probably chaotic, and its dimensionless parameters cannot yet be reproduced on a laboratory scale. It is accessible only to theory and to measurements made at and above the earth's surface. These measurements include essentially all geophysical types. Gravity and seismology give evidence for undulations in the core-mantle boundary (CMB) and for temperature variations in the lower mantle which can affect core convection and hence the dynamo. VLBI measurements of the variations in the Chandler wobble and length of day are affected by, among other things, the electromagnetic and mechanical transfer of angular momentum across the CMB. Finally, measurements of the vector magnetic field, its intensity, or its direction, give the most direct access to the core dynamo and the electrical conductivity of the lower mantle. The 120 gauss coefficients of degrees up to 10 probably come from the core, with only modest interference by mantle conductivity and crustal magnetization. By contrast, only three angular accelerations enter the problem of angular momentum transfer across the CMB. Satellite measurements of the vector magnetic field are uniquely able to provide the spatial coverage required for extrapolation to the CMB, and to isolate and measure certain magnetic signals which to the student of the geodynamo represent noise, but which are of great interest elsewhere in geophysics. Here, these claims are justified and the mission parameters likely to be scientifically most useful for observing the geodynamo system are described

    HiRes deconvolution of Spitzer infrared images

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    Spitzer provides unprecedented sensitivity in the infrared (IR), but the spatial resolution is limited by a relatively small aperture (0.85 m) of the primary mirror. In order to maximize the scientific return it is desirable to use processing techniques which make the optimal use of the spatial information in the observations. We have developed a deconvolution technique for Spitzer images. The algorithm, "HiRes" and its implementation has been discussed by Backus et al. in 2005. Here we present examples of Spitzer IR images from the Infrared Array Camera (IRAC) and MIPS, reprocessed using this technique. Examples of HiRes processing include a variety of objects from point sources to complex extended regions. The examples include comparison of Spitzer deconvolved images with high-resolution Keck and Hubble Space Telescope images. HiRes deconvolution improves the visualization of spatial morphology by enhancing resolution (to sub-arcsecond levels in the IRAC bands) and removing the contaminating sidelobes from bright sources. The results thereby represent a significant improvement over previously-published Spitzer images. The benefits of HiRes include (a) sub-arcsec resolution (~0".6-0".8 for IRAC channels); (b) the ability to detect sources below the diffraction-limited confusion level; (c) the ability to separate blended sources, and thereby provide guidance to point-source extraction procedures; (d) an improved ability to show the spatial morphology of resolved sources. We suggest that it is a useful technique to identify features which are interesting enough for follow-up deeper analysis
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