308 research outputs found

    Drip cooling of lactating sows

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    Twenty eight sows and gilts were used to evaluate the value of drip sprinkling to reduce heat stress in lactating sows. Respiration rates for sprinkled sows were significantly lower than those of controls. Daily feed intake was significantly higher for wetted sows versus the unwetted controls. No differences were observed between groups on number of pigs born alive, dead, number weaned or pig birth weight.; Swine Day, Manhattan, KS, November 10, 198

    Detection, Quantification and Classification of Ripened Tomatoes: A Comparative Analysis of Image Processing and Machine Learning

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    In this paper, specifically for detection of ripe/unripe tomatoes with/without defects in the crop field, two distinct methods are described and compared. One is a machine learning approach, known as ‘Cascaded Object Detector’ and the other is a composition of traditional customized methods, individually known as ‘Colour Transformation’, ‘Colour Segmentation’ and ‘Circular Hough Transformation’. The (Viola Jones) Cascaded Object Detector generates ‘histogram of oriented gradient’ (HOG) features to detect tomatoes. For ripeness checking, the RGB mean is calculated with a set of rules. However, for traditional methods, color thresholding is applied to detect tomatoes either from a natural or solid background and RGB colour is adjusted to identify ripened tomatoes. In this work, Colour Segmentation is applied in the detection of tomatoes with defects, which has not previously been applied under machine learning techniques. The function modules of this algorithm are fed formatted images, captured by a camera mounted on a mobile robot. This robot was designed, built and operated in a tomato field to identify and quantify both green and ripened tomatoes as well as to detect damaged/blemished ones. This algorithm is shown to be optimally feasible for any micro-controller based miniature electronic devices in terms of its run time complexity of O(n3) for traditional method in best and average cases. Comparisons show that the accuracy of the machine learning method is 95%, better than that of the Colour Segmentation Method using MATLAB. This result is potentially significant for farmers in crop fields to identify the condition of tomatoes quickly

    Estradiol and testosterone levels in patients undergoing partial hepatectomy - A possible signal for hepatic regeneration?

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    In five adult male patients undergoing a 40-60% partial hepatectomy, serum sex hormone levels before and after hepatic resection were determined. Blood was drawn immediately prior to each surgical procedure and at specified time points postoperatively. Compared to hormone levels found prior to surgery, following major hepatic resection, estradiol levels increase at 24 and 48 hr, while testosterone levels decline, being significantly reduced at 96 and 144 hr. These data demonstrate that adult males who undergo a 40-60% partial hepatectomy experience alterations in their sex hormone levels similar to those observed in male rats following a 70% hepatectomy. These changes in sex hormone levels have been associated in animals with an alteration of the sex hormone receptor status of the liver that is thought to participate in the initiation of the regenerative response. These studies suggest, but do not prove, that in man, as in the case of the rat, sex hormones may participate in the initiation of or at least modulate in part the regenerative response that occurs following a major hepatic resection. © 1989 Plenum Publishing Corporation

    Kepler Mission Stellar and Instrument Noise Properties

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    Kepler Mission results are rapidly contributing to fundamentally new discoveries in both the exoplanet and asteroseismology fields. The data returned from Kepler are unique in terms of the number of stars observed, precision of photometry for time series observations, and the temporal extent of high duty cycle observations. As the first mission to provide extensive time series measurements on thousands of stars over months to years at a level hitherto possible only for the Sun, the results from Kepler will vastly increase our knowledge of stellar variability for quiet solar-type stars. Here we report on the stellar noise inferred on the timescale of a few hours of most interest for detection of exoplanets via transits. By design the data from moderately bright Kepler stars are expected to have roughly comparable levels of noise intrinsic to the stars and arising from a combination of fundamental limitations such as Poisson statistics and any instrument noise. The noise levels attained by Kepler on-orbit exceed by some 50% the target levels for solar-type, quiet stars. We provide a decomposition of observed noise for an ensemble of 12th magnitude stars arising from fundamental terms (Poisson and readout noise), added noise due to the instrument and that intrinsic to the stars. The largest factor in the modestly higher than anticipated noise follows from intrinsic stellar noise. We show that using stellar parameters from galactic stellar synthesis models, and projections to stellar rotation, activity and hence noise levels reproduces the primary intrinsic stellar noise features.Comment: Accepted by ApJ; 26 pages, 20 figure

    Influence of nitrogen form on the phytoextraction of cadmium by a newly discovered hyperaccumulator Carpobrotus rossii

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    Using hyperaccumulator plants is an important method to remove heavy metals from contaminated land. Carpobrotus rossii, a newly found Cd hyperaccumulator, has shown potential to remediate Cd-contaminated soils. This study examined the effect of nitrogen forms on Cd phytoextraction by C. rossii. The plants were grown for 78 days in an acid soil spiked with 20 mg Cd kg(-1) and supplied with (NH4)(2)SO4, Ca(NO3)(2), urea, and chicken manure as nitrogen (N) fertilizers. Nitrification inhibitor dicyandiamide (DCD) was applied to maintain the ammonium (NH4+) form. Nitrogen fertilization increased shoot biomass but decreased root biomass with the highest shoot biomass occurring in the manure treatment. Compared to the no-N control, urea application did not affect shoot Cd concentration, but increased Cd content by 17 % due to shoot biomass increase. Chicken manure significantly decreased CaCl2-extractable Cd in soil, and the Cd concentration and total Cd uptake in the plant. Rhizosphere pH was the highest in the manure treatment and the lowest in the NH4+ treatments. The manure and nitrate (NO3-) treatments tended to have higher rhizosphere pH than their respective bulk soil pH, whereas the opposite was observed for urea and NH4+ treatments. Furthermore, the concentrations of extractable Cd in soil and Cd in the plant correlated negatively with rhizosphere pH. The study concludes that urea significantly enhanced the Cd phytoaccumulation by C. rossii while chicken manure decreased Cd availability in soil and thus the phytoextraction efficiency

    Vortex merger near a topographic slope in a homogeneous rotating fluid

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    This work is a contribution to the PHYSINDIEN research program. It was supported by CNRS-RFBR contract PRC 1069/16-55-150001.The effect of a bottom slope on the merger of two identical Rankine vortices is investigated in a two dimensional, quasi-geostrophic, incompressible fluid. When two cyclones initially lie parallel to the slope, and more than two vortex diameters away from the slope, the critical merger distance is unchanged. When the cyclones are closer to the slope, they can merge at larger distances, but they lose more mass into filaments, thus weakening the efficiency of merger. Several effects account for this: the topographic Rossby wave advects the cyclones, reduces their mutual distance and deforms them. This along shelf wave breaks into filaments and into secondary vortices which shear out the initial cyclones. The global motion of fluid towards the shallow domain and the erosion of the two cyclones are confirmed by the evolution of particles seeded both in the cyclone sand near the topographic slope. The addition of tracer to the flow indicates that diffusion is ballistic at early times. For two anticyclones, merger is also facilitated because one vortex is ejected offshore towards the other, via coupling with a topographic cyclone. Again two anticyclones can merge at large distance but they are eroded in the process. Finally, for taller topographies, the critical merger distance is again increased and the topographic influence can scatter or completely erode one of the two initial cyclones. Conclusions are drawn on possible improvements of the model configuration for an application to the ocean.PostprintPeer reviewe

    Emerging Infectious Disease leads to Rapid Population Decline of Common British Birds

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    Emerging infectious diseases are increasingly cited as threats to wildlife, livestock and humans alike. They can threaten geographically isolated or critically endangered wildlife populations; however, relatively few studies have clearly demonstrated the extent to which emerging diseases can impact populations of common wildlife species. Here, we report the impact of an emerging protozoal disease on British populations of greenfinch Carduelis chloris and chaffinch Fringilla coelebs, two of the most common birds in Britain. Morphological and molecular analyses showed this to be due to Trichomonas gallinae. Trichomonosis emerged as a novel fatal disease of finches in Britain in 2005 and rapidly became epidemic within greenfinch, and to a lesser extent chaffinch, populations in 2006. By 2007, breeding populations of greenfinches and chaffinches in the geographic region of highest disease incidence had decreased by 35% and 21% respectively, representing mortality in excess of half a million birds. In contrast, declines were less pronounced or absent in these species in regions where the disease was found in intermediate or low incidence. Also, populations of dunnock Prunella modularis, which similarly feeds in gardens, but in which T. gallinae was rarely recorded, did not decline. This is the first trichomonosis epidemic reported in the scientific literature to negatively impact populations of free-ranging non-columbiform species, and such levels of mortality and decline due to an emerging infectious disease are unprecedented in British wild bird populations. This disease emergence event demonstrates the potential for a protozoan parasite to jump avian host taxonomic groups with dramatic effect over a short time period

    Retrospective survey for sialidase activity in Mycoplasma pneumoniae isolates from cases of community-acquired pneumonia

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    <p>Abstract</p> <p>Background</p> <p>Sialidase is a well-known virulence factor of other respiratory pathogens, but was only recently documented to occur in some species of <it>Mycoplasma</it>. The sialidase activity expressed can vary quantitatively among strains within a species of mycoplasma, from undetectable to amounts that correlate positively with strain virulence. Very few isolates of <it>Mycoplasma pneumoniae </it>had ever been examined for sialidase activity, so it was unknown whether sialidase may contribute to diseases involving this species.</p> <p>Findings</p> <p>No sialidase activity was detected by spectrofluorometric assay of 15 laboratory strains and 91 clinical isolates of <it>M. pneumoniae </it>banked over many years from patients having radiologically-confirmed, uncomplicated community-acquired pneumonia.</p> <p>Conclusions</p> <p>The annotated genome of strain M129 (GenBank <ext-link ext-link-id="NC_000912" ext-link-type="gen">NC_000912</ext-link>, <ext-link ext-link-id="ATCC29342" ext-link-type="gen">ATCC 29342</ext-link>), also isolated from a patient with pneumonia, accurately represents the absence of sialidase genes from strains of <it>M. pneumoniae </it>typically associated with uncomplicated community-acquired pneumonia. A possible involvement of sialidase in neurologic or other extra-respiratory manifestations of <it>M. pneumoniae </it>mycoplasmosis remains to be investigated.</p

    Observations of Nutrient Supply by Mesoscale Eddy Stirring and Small-Scale Turbulence in the Oligotrophic North Atlantic

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    Sustaining biological export over the open ocean requires a physical supply of nutrients to the mixed layer and thermocline. The relative importance of diapycnal mixing, diapycnal advection and isopycnal stirring by mesoscale eddies in providing this nutrient supply is explored using a field campaign in oligotrophic waters in the subtropical North Atlantic, consisting of transects over and off the mid-Atlantic ridge. Eddy stirring rates are estimated from the excess temperature variance dissipation relative to the turbulent kinetic energy dissipation, and using eddy statistics from satellite observations combined with 9-month-long mooring data. The vertical nutrient fluxes by diapycnal mixing, diapycnal advection and isopycnal mesoscale eddy stirring are assessed using nitrate measurements from observations or a climatology. Diapycnal mixing and advection provide a nutrient supply within the euphotic zone, but a loss of nutrients within the upper thermocline. Eddy stirring augments, and is comparable to, the diapycnal transfer of nutrients within the summertime upper thermocline, while also acting to replenish nutrients within the deeper parts of the thermocline. The eddy supply of nitrate is relatively small in the centre of the subtropical gyre, reaching up to 0.06 mol N m−2yr−1, but is likely to be enhanced on the flanks of the gyre due to larger isopycnal slopes and lateral nitrate gradients. The nutrient supply to the euphotic zone is achieved via a multi-stage mechanism: a diapycnal transfer of nutrients by small-scale turbulence to the euphotic zone, and an isopycnal stirring of nutrients by mesoscale eddies replenishing nutrients in the upper thermocline. Plain Language Summary Phytoplankton growth requires a supply of nutrients to the base of the euphotic zone, which is usually provided by a combination of vertical mixing or vertical upwelling of nutrients. However, in the oligotrophic waters of the central North Atlantic, it is unclear how the vertical supply of nutrients is sustained. Here we use field data to explore the roles of mixing across density surfaces, advection across density surfaces and mesoscale eddy stirring along density surfaces in supplying nutrients to some of the most nutrient-depleted surface waters in the central North Atlantic. Diapycnal mixing and advection are found to be important in supplying nutrients to the euphotic zone during summer, but at the expense of eroding the nutrients in the upper thermocline. In contrast, mesoscale eddy stirring augments the diapycnal supply of nutrients to the euphotic zone, and replenishes nutrients in the upper thermocline
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