1,470 research outputs found

    Pseudo-Automorphisms of positive entropy on the blowups of products of projective spaces

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    We use a concise method to construct pseudo-automorphisms f_n of the first dynamical degree d_1(f_n) > 1 on the blowups of the projective n-space for all n > 1 and more generally on the blowups of products of projective spaces. These f_n, for n = 3 have positive entropy, and for n > 3 seem to be the first examples of pseudo-automorphisms with d_1(f_n) > 1 (and of non-product type) on rational varieties of higher dimensions.Comment: Mathematische Annalen (to appear

    Using virtual spatial audio to aide visually impaired atheletes

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    Many people with visual impairments actively play soccer, however the task of making the game accessible is met with significant challenges. These challenges include: the need to constantly talk to signify location and detecting the positions of silent objects on the field. Our work aims to discover methods to help persons with visual impairments play soccer more efficiently and safely

    Performance of Beef Replacement Heifers Supplemented With Dried Distillers Grains With Solubles Versus a Mixture of Soybean Meal and Finely Ground Sorghum Grain

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    Costs of feed, labor, and equipment to develop heifers in a traditional confined feeding system are relatively high. Producers can greatly reduce input costs by developing heifers on dormant native range; however, heifers are unable to consume sufficient protein from the forage base. Suboptimal protein intake will reduce forage digestion and result in poor performance. Supplemental protein is required during these times to increase forage intake and digestion. The most efficient way of providing supplemental protein to heifers consuming lowquality (\u3c7% crude protein) forage is by feeding high-protein supplements (\u3e30% crude protein). Producers traditionally have used high-quality oilseed meals to supplement the necessary protein, but expansion of the ethanol industry has made dried distillers grains with solubles (DDGS) a potentially less expensive supplement option for producers in corn- and sorghum-producing areas. The objective of this study was to evaluate the effects of daily supplementation of DDGS vs. a mixture of soybean meal and finely ground sorghum grain on performance of replacement heifers grazing low-quality dormant native range

    Effects of Altering Supplementation Frequency During the Pre-Partum Period of Beef Cows Grazing Dormant Native Range

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    Spring-calving beef cattle that are grazing low-quality (\u3c 7% crude protein) dormant forage typically are unable to meet their maintenance requirements for protein. Providing a protein supplement (\u3e 30% crude protein) is recommended to decrease losses of body weight and body condition. Nutrient supplementation when forage quality is poor or limited is one of the largest expenditures for forage-based beef cattle operations. The expansion of the ethanol industry has afforded many producers in corn and sorghum-producing regions an alternative to traditional oilseed-based protein supplements. The availability and nutrient profile of distiller’s grains with solubles (DDG) has made it popular as a supplement for cows that are grazing dormant lowquality forages. Decreasing supplementation frequency reduces costs for labor and fuel. Previous research has shown no difference in body weights or body condition scores of cows supplemented with distiller’s grains daily, once every three days, or once every six days; however, the proportion of cows that ate hay during the 60 minutes immediately after supplementation was less on the day of supplementation for cows supplemented once every six days compared to cows supplemented daily. The observed decrease in hay consumption following supplementation could potentially decrease total organic matter intake during late gestation. More frequent supplementation may increase organic matter intake and improve performance during the month before parturition. Therefore, the objective of this study was to evaluate effects of altering frequency of supplementing distiller’s grains during the last 28 days of gestation with respect to performance of spring-calving beef cows consuming low-quality dormant native range

    Performance of Beef Replacement Heifers Supplemented with Dried Distillers Grains or a Mixture of Soybean Meal and Ground Sorghum Grain

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    The feed, labor, and equipment costs of developing heifers in a confined feeding system are relatively high. High Plains beef producers can reduce input costs by developing heifers on dormant native range; however, heifers are typically unable to consume sufficient crude protein (CP) from the low-quality (\u3c 7% CP) forage base. Insufficient dietary protein reduces forage digestion and performance potential of growing heifers. Supplementing protein when forage quality was poor has previously been reported to increase forage intake and forage digestibility, which resulted in acceptable levels of performance. An efficient means of supplying supplemental protein to heifers consuming low-quality forage is through the use of supplements with relatively high crude protein concentrations (\u3e 30% CP). Traditionally, producers have used oilseed meals in this capacity, but with the expansion of the ethanol industry, dried distillers grains with solubles (DDG) have become widely available as an alternative protein source for producers in corn and sorghum-producing regions. Adequate heifer body weight and body condition score at first breeding are essential to minimize age at first calving and to increase lifetime productivity. Therefore, the objective of our study was to evaluate the effects of supplementation of DDG or an approximately isonitrogenous mixture of soybean meal and ground sorghum grain on growth and reproductive performance of replacement heifers grazing low-quality, dormant native range

    Effects of Altering Supplementation Frequency During the Pre-Partum Period of Beef Cows Grazing Dormant Native Range

    Get PDF
    Spring-calving beef cattle that are grazing low-quality (\u3c 7% crude protein) dormant forage typically are unable to meet their maintenance requirements for protein. Providing a protein supplement (\u3e 30% crude protein) is recommended to decrease losses of body weight and body condition. Nutrient supplementation when forage quality is poor or limited is one of the largest expenditures for forage-based beef cattle operations. The expansion of the ethanol industry has afforded many producers in corn and sorghum-producing regions an alternative to traditional oilseed-based protein supplements. The availability and nutrient profile of distiller’s grains with solubles (DDG) has made it popular as a supplement for cows that are grazing dormant low-quality forages. Decreasing supplementation frequency reduces costs for labor and fuel. Previous research has shown no difference in body weights or body condition scores of cows supplemented with distiller’s grains daily, once every three days, or once every six days; however, the proportion of cows that ate hay during the 60 minutes immediately after supplementation was less on the day of supplementation for cows supplemented once every six days compared to cows supplemented daily. The observed decrease in hay consumption following supplementation could potentially decrease total organic matter intake during late gestation. More frequent supplementation may increase organic matter intake and improve performance during the month before parturition. Therefore, the objective of this study was to evaluate effects of altering frequency of supplementing distiller’s grains during the last 28 days of gestation with respect to performance of spring-calving beef cows consuming low-quality dormant native range

    Generalised dimensions of measures on almost self-affine sets

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    We establish a generic formula for the generalised q-dimensions of measures supported by almost self-affine sets, for all q>1. These q-dimensions may exhibit phase transitions as q varies. We first consider general measures and then specialise to Bernoulli and Gibbs measures. Our method involves estimating expectations of moment expressions in terms of `multienergy' integrals which we then bound using induction on families of trees

    Edge pixel response studies of edgeless silicon sensor technology for pixellated imaging detectors

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    Silicon sensor technologies with reduced dead area at the sensor's perimeter are under development at a number of institutes. Several fabrication methods for sensors which are sensitive close to the physical edge of the device are under investigation utilising techniques such as active-edges, passivated edges and current-terminating rings. Such technologies offer the goal of a seamlessly tiled detection surface with minimum dead space between the individual modules. In order to quantify the performance of different geometries and different bulk and implant types, characterisation of several sensors fabricated using active-edge technology were performed at the B16 beam line of the Diamond Light Source. The sensors were fabricated by VTT and bump-bonded to Timepix ROICs. They were 100 and 200 μ m thick sensors, with the last pixel-to-edge distance of either 50 or 100 μ m. The sensors were fabricated as either n-on-n or n-on-p type devices. Using 15 keV monochromatic X-rays with a beam spot of 2.5 μ m, the performance at the outer edge and corners pixels of the sensors was evaluated at three bias voltages. The results indicate a significant change in the charge collection properties between the edge and 5th (up to 275 μ m) from edge pixel for the 200 μ m thick n-on-n sensor. The edge pixel performance of the 100 μ m thick n-on-p sensors is affected only for the last two pixels (up to 110 μ m) subject to biasing conditions. Imaging characteristics of all sensor types investigated are stable over time and the non-uniformities can be minimised by flat-field corrections. The results from the synchrotron tests combined with lab measurements are presented along with an explanation of the observed effects

    Algebraic entropy for semi-discrete equations

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    We extend the definition of algebraic entropy to semi-discrete (difference-differential) equations. Calculating the entropy for a number of integrable and non integrable systems, we show that its vanishing is a characteristic feature of integrability for this type of equations
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