1,097 research outputs found

    USING TIME-SERIES INTERVENTION ANALYSIS TO MODEL COW HEART RATE AFFECTED BY PROGRAMMED AUDIO AND ENVIRONMENTAL/PHYSIOLOGICAL CUES

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    This research is the first use of Box-Jenkins time-series models to describe changes in heart rate (HR) of free-ranging crossbred cows (Bos taurus) receiving both programmed audio cues from directional virtual fencing (DVFTM) devices and non-programmed environmental/physiological cues. The DVFTM device is designed to control the animal\u27s location on the landscape. Polar Accurex® devices were used to capture HR every minute between 19 and 24 March 2003, when three mature free-ranging beef cows, previously habituated to the DVFTM device, were confined to a brush-infested area of an arid rangeland paddock. Global positioning system (GPS) electronics were used to record each cow\u27s location approximately every minute while it was in a 58 ha virtual paddock (VPTM) and every second when it penetrated a virtual boundary (VBTM). The cows never escaped through the VBTM, although they penetrated it a total of 26 times in 11 different events, at which times they received programmed audio cues lasting from 1 to 56 s. Plots of these data reveal that HR spikes from programmed audio cues all fell within textbook range for cow HR (40-186 beats per minute, bpm). Heart rate spikes were analyzed using Box-Jenkins intervention analysis models, which showed that for both audio and selected environmental/physiological events, HR spikes typically returned to pre-cuing baseline levels in about one minute. However, the longest return-time to baseline (about four minutes) was for an environmental/physiological event of unknown origin. HR, animal location, weather and other electronic data should be measured at equally-spaced time intervals using a single time stamp to accurately associate HR changes with possible causes

    Effects of corn steep liquor supplementation on performance and herbivory patterns of beef

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    Increased grazing pressure on sericea lespedeza by beef cattle, the most economically relevant herbivore in the region, may slow its spread and facilitate some measure of biological control. Unfortunately, mature plants contain high levels of condensed tannins that decrease protein digestion by beef cattle, and these compounds are potent deterrents to grazing. Supplementing corn steep liquor has been shown to alleviate the negative effects associated with ingestion of condensed tannins when beef cattle are fed prairie hay contaminated with sericea lespedeza. In addition, beef cows supplemented with corn steep liquor did not discriminate between sericea lespedeza-contaminated and sericea lespedeza-free prairie hay in a preference trial. Therefore, the objective of our study was to evaluate the effects of supplemental corn steep liquor on herbivory patterns and performance of beef cows grazing native tallgrass rangeland infested with sericea lespedeza

    VARIANCE INFLATION FACTORS IN REGRESSION MODELS WITH DUMMY VARIABLES

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    Variance Inflation Factors (VIFs) are used to detect collinearity among predictors in regression models. Textbook explanation of collinearity and diagnostics such as VIFs have focused on numeric predictors as being co-linear or co-planar , with little attention paid to VIFs when a dummy variable is included in the model. This work was motivated by two regression models with high VIFs, where standard\u27 interpretations of causes of collinearity made no sense. The first was an alfalfa-breeding model with two numeric predictors and two dummy variables. The second was an economic model with one numeric predictor, one dummy and the numeric x dummy cross-product. This paper gives formulas for VIFs for several regression models with a dummy variable which indicate that these VIFs are functions of the numeric predictors\u27 means, sums of squares and sample sizes within the two dummy groups. The economic regression model is also presented to illustrate how high VIFs occurred in this data. Researchers should be cautious in using high VIFs as a reason for deleting predictors in general but especially if dummy variables are involved. It is recommended that collinearity diagnostics be applied to the numeric predictors first to check for collinearity without the influence of any dummies, then add dummy variables in one at a time to see their effect on VIFs

    Soil quality after eight years under high tunnels

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    The sustainability of soil quality under high tunnels will influence management of high tunnels currently in use and grower decisions regarding design and management of new high tunnels to be constructed. Soil quality was quantified using measures of soil pH, salinity, total carbon, and particulate organic matter (POM) carbon in a silt loam soil that had been in vegetable production under high tunnels at the research station in Olathe, KS, for eight years. Soil under high tunnels was compared with that in adjacent fields in both a conventional and an organic management system. The eight-year presence of high tunnels under the conventional management system resulted in increased soil pH and salinity but did not affect soil carbon. In the organic management system, high tunnels did not affect soil pH, increased soil salinity, and influenced soil carbon (C) pools with an increase in POM carbon. The increases in soil salinity were not enough to be detrimental to crops. These results indicate that soil quality was not adversely affected by eight years under stationary high tunnels managed with conventionally or organically produced vegetable crops

    Effects of experimental design and its role in interpretation of results

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    A total of 256 weanling pigs (PIC TR4 × 1050, initially 13.8 lb and 21 d of age) were used in a 28-d growth trial to compare allotment methods of a completely randomized design (CRD) and a randomized complete block design (RCBD). Two treatments were used to compare these designs: a negative control with no antibiotic or growth promoter and a positive control with 35 g/ton of Denagard (Novartis Animal Health), 400 g/ton of chlortetracycline, and zinc from zinc oxide at 3,000 and 2,000 ppm in Phases 1 and 2, respectively. Experimental diets were fed in 2 phases: Phase 1 from d 0 to 14 and Phase 2 from d 14 to 28. Eight replications of each dietary treatment were used for each experimental design. The first statistical model examined dietary treatment, experimental design, and the design × dietary treatment as fixed factors. With the exception of pens in the CRD having a trend for improved (P 0.11) for any responses variables, indicating that treatment means reacted similarly in each of the experimental designs. In both the CRD and the RCBD, pig weights were increased (P < 0.003) with supplementation of growth promoters on d 14 and 28. Variation of weight within pen remained the same in the CRD from d 0 to 28 at approximately 20% but increased from 3% on d 0 to 10% on d 28 for the RCBD. Dietary addition of growth promoters increased (P < 0.003) ADG and ADFI and improved F/G (P < 0.04) in both the CRD and RCBD from d 0 to 14, with lower P-values for the CRD than the RCBD. From d 14 to 28, the CRD detected an increase (P < 0.001) in ADG and ADFI with dietary addition of growth promoters, and the RCBD detected an increase (P < 0.001) only in ADFI. Over the entire 28-d trial, growth promoters increased (P < 0.001) ADG and ADFI and improved (P < 0.03) F/G in the CRD and increased (P < 0.02) ADG and ADFI in the RCBD. Lower standard errors for the difference were also estimated for ADG and F/G in the CRD than in the RCBD from d 0 to 28. The average corrected relative efficiency for each of the three periods was 2.08 for ADG, 5.05 for ADFI, and 0.80 for F/G. The gain and intake values suggest that the added variation explained by blocks in the RCBD was beneficial for achieving a more reduced estimate of σ2error compared with analyzing that particular data set as a CRD. The variance ratios of the CRD to RCBD from d 0 to 28 depict the different responses well with ADG at 0.67, ADFI at 1.70, and F/G at 0.22. When these ratios were compared with an F-test, they were well below the upper critical limit of 4.60, suggesting that the CRD offered estimates for σ2error similar to those of the RCBD. With the same estimate for σ2error, the non-centrality parameter for each design would be similar, and therefore, the increase in degrees of freedom (DF) for the error term would lead to greater power to detect differences in the CRD. Additional studies are needed to verify these results and determine whether blocking is an efficient use of error DF

    Forage selection preferences of experienced cows and naïve heifers grazing native tallgrass range during winter

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    Beef Cattle Research, 2011 is known as Cattlemen’s Day, 2011Estimating the nutritive value of a grazing animal’s diet is a significant challenge. Description of the botanical composition of a grazed diet is vital in that regard. Microhistological analysis of fecal material has been used for estimating the botanical composition of wild and domestic ungulate diets since first described by Baumgartner and Martin in 1939. Little research has been conducted on the diet selection preferences of multiparous beef cows compared to primiparous beef cows. We hypothesized that foraging strategies change as cows age. To that end, our objective was to characterize differences in diet selection between experienced multiparous and naïve primiparous beef cows grazing dormant, native tallgrass pastures during winter

    76 T dwarfs from the UKIDSS LAS : benchmarks, kinematics and an updated space density

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    We report the discovery of 76 new T dwarfs from the UKIRT Infrared Deep Sky Survey (UKIDSS) Large Area Survey (LAS). Near-infrared broad- and narrow-band photometry and spectroscopy are presented for the new objects, along with Wide-field Infrared Survey Explorer (WISE) and warm-Spitzer photometry. Proper motions for 128 UKIDSS T dwarfs are presented from a new two epoch LAS proper motion catalogue. We use these motions to identify two new benchmark systems: LHS 6176AB, a T8p+M4 pair and HD 118865AB, a T5.5+F8 pair. Using age constraints from the primaries and evolutionary models to constrain the radii, we have estimated their physical properties from their bolometric luminosity. We compare the colours and properties of known benchmark T dwarfs to the latest model atmospheres and draw two principal conclusions. First, it appears that the H - [4.5] and J - W2 colours are more sensitive to metallicity than has previously been recognized, such that differences in metallicity may dominate over differences in T-eff when considering relative properties of cool objects using these colours. Secondly, the previously noted apparent dominance of young objects in the late-T dwarf sample is no longer apparent when using the new model grids and the expanded sample of late-T dwarfs and benchmarks. This is supported by the apparently similar distribution of late-T dwarfs and earlier type T dwarfs on reduced proper motion diagrams that we present. Finally, we present updated space densities for the late-T dwarfs, and compare our values to simulation predictions and those from WISE.Peer reviewe

    A 1500 deg2 near infrared proper motion catalogue from the UKIDSS Large Area Survey

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    The United Kingdom Infrared Deep Sky Survey (UKIDSS) Large Area Survey (LAS) began in 2005, with the start of the UKIDSS programme as a 7 year effort to survey roughly 4000 deg2 at high Galactic latitudes in Y, J, H and K bands. The survey also included a significant quantity of two epoch J band observations, with an epoch baseline greater than 2 years to calculate proper motions. We present a near-infrared proper motion catalogue for the 1500 deg2 of the two epoch LAS data, which includes 135 625 stellar sources and a further 88 324 with ambiguous morphological classifications, all with motions detected above the 5σ level. We developed a custom proper motion pipeline which we describe here. Our catalogue agrees well with the proper motion data supplied for a 300 deg2 subset in the current Wide Field Camera Science Archive (WSA) 10th data release (DR10) catalogue, and in various optical catalogues, but it benefits from a larger matching radius and hence a larger upper proper motion detection limit. We provide absolute proper motions, using LAS galaxies for the relative to absolute correction. By using local second-order polynomial transformations, as opposed to linear transformations in the WSA, we correct better for any local distortions in the focal plane, not including the radial distortion that is removed by the UKIDSS pipeline. We present the results of proper motion searches for new brown dwarfs and white dwarfs. We discuss 41 sources in the WSA DR10 overlap with our catalogue with proper motions >300 mas yr−1, several of which are new detections. We present 15 new candidate ultracool dwarf binary systems

    A survey of the clinical acceptability of screening for postnatal depression in depressed and non-depressed women

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    BACKGROUND: Information on clinical acceptability is needed when making cost-utility decisions about health screening implementation. Despite being in use for two decades, most data on the clinical acceptability of the Edinburgh Postnatal Depression Scale (EPDS) come from qualitative reports, or include relatively small samples of depressed women. This study aimed to measure acceptability in a survey of a relatively large, community sample with a high representation of clinically depressed women. METHODS: Using mail, telephone and face-to-face interview, 920 postnatal women were approached to take part in a survey on the acceptability of the EPDS, including 601 women who had screened positive for depression and 245 who had received DSM-IV diagnoses of depression. Acceptability was measured on a 5-point Likert scale of comfort ranging from "Not Comfortable", through "Comfortable" to "Very Comfortable". RESULTS: The response rate was just over half for postal surveys (52%) and was 100% for telephone and face-to-face surveys (432, 21 and 26 respondents for postal, telephone and face-to-face surveys respectively) making 479 respondents in total. Of these, 81.2% indicated that screening with the EPDS had been in the range of "Comfortable" to "Very Comfortable". The other 18.8 % rated screening below the "Comfortable" point, including a small fraction (4.3%) who rated answering questions on the EPDS as "Not Comfortable" at the extreme end of the scale. Comfort was inversely related to EPDS score, but the absolute size of this effect was small. Almost all respondents (97%) felt that screening was desirable. CONCLUSION: The EPDS had good acceptability in this study for depressed and non-depressed women. Women's views on the desirability of postnatal depression screening appear to be largely independent of personal level of comfort with screening. These results should be useful to policy-makers and are broadly supportive of the Edinburgh Postnatal Depression Scale as a suitable tool for universal perinatal depression screening

    The cost of diagnostic uncertainty: a prospective economic analysis of febrile children attending an NHS emergency department.

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    BACKGROUND: Paediatric fever is a common cause of emergency department (ED) attendance. A lack of prompt and definitive diagnostics makes it difficult to distinguish viral from potentially life-threatening bacterial causes, necessitating a cautious approach. This may result in extended periods of observation, additional radiography, and the precautionary use of antibiotics (ABs) prior to evidence of bacterial foci. This study examines resource use, service costs, and health outcomes. METHODS: We studied an all-year prospective, comprehensive, and representative cohort of 6518 febrile children (aged < 16 years), attending Alder Hey Children's Hospital, an NHS-affiliated paediatric care provider in the North West of England, over a 1-year period. Performing a time-driven and activity-based micro-costing, we estimated the economic impact of managing paediatric febrile illness, with focus on nurse/clinician time, investigations, radiography, and inpatient stay. Using bootstrapped generalised linear modelling (GLM, gamma, log), we identified the patient and healthcare provider characteristics associated with increased resource use, applying retrospective case-note identification to determine rates of potentially avoidable AB prescribing. RESULTS: Infants aged less than 3 months incurred significantly higher resource use than any other age group, at £1000.28 [95% CI £82.39-£2993.37] per child, (p < 0.001), while lesser experienced doctors exhibited 3.2-fold [95% CI 2.0-5.1-fold] higher resource use than consultants (p < 0.001). Approximately 32.4% of febrile children received antibiotics, and 7.1% were diagnosed with bacterial infections. Children with viral illnesses for whom antibiotic prescription was potentially avoidable incurred 9.9-fold [95% CI 6.5-13.2-fold] cost increases compared to those not receiving antibiotics, equal to an additional £1352.10 per child, predominantly resulting from a 53.9-h increase in observation and inpatient stay (57.1 vs. 3.2 h). Bootstrapped GLM suggested that infants aged below 3 months and those prompting a respiratory rate 'red flag', treatment by lesser experienced doctors, and Manchester Triage System (MTS) yellow or higher were statistically significant predictors of higher resource use in 100% of bootstrap simulations. CONCLUSION: The economic impact of diagnostic uncertainty when managing paediatric febrile illness is significant, and the precautionary use of antibiotics is strongly associated with increased costs. The use of ED resources is highest among infants (aged less than 3 months) and those infants managed by lesser experienced doctors, independent of clinical severity. Diagnostic advances which could increase confidence to withhold antibiotics may yield considerable efficiency gains in these groups, where the perceived risks of failing to identify potentially life-threatening bacterial infections are greatest
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