9,652 research outputs found

    ANALYSIS OF THE SPATIAL DISTRIBUTION OF SUGARBEET PLANTS

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    The spatial distribution of emerged sugarbeet plants is an important aspect of the performance of sugarbeet planters. Three major components influencing the spatial distribution are the ability to drop a single seed at a time, the ability to drop the seeds a fixed distance apart, and the ability of the seed to emerge. A model has been developed to describe the distribution of the spacing between emerged sugarbeet plants. The model consists of a mixture of normal and gamma distributions. The spatial data consists of the distance between neighboring emerged plants. Spatial data was collected on 7 planters operated at 3 speeds using both pelleted and encrusted seeds. Four replicates were obtained of each treatment combination. Approximate maximum likelihood estimates of the parameters were obtained separately for each replicate of the treatment combinations

    In vitro and in vivo effects of the PPAR-alpha agonists fenofibrate and retinoic acid in endometrial cancer.

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    UNLABELLED: Fenofibrate, an agonist of PPAR-alpha, in doses above 25 microM, inhibits proliferation and induces apoptosis in Ishikawa endometrial cancer cells. We show that these effects are potentiated by retinoic acid, an agonist of the retinoid-X-receptor. DNA content analysis shows that G1/S phase progression through the cell cycle is inhibited. Independent Component Analysis of gene microarray experiments demonstrated downregulation of Cyclin D1 (CCND1) and associated changes in cell cycle gene expression. Expression of PPAR-alpha mRNA was reduced by >75% using RNA-interference but this resulted in only minor changes in biological effects. A nude mouse model of endometrial carcinoma was used to investigate the effect of fenofibrate in vivo but failed to show consistent inhibition of tumour growth. CONCLUSION: The combination of fenofibrate and retinoic acid is a potent inhibitor of Ishikawa endometrial cancer cell growth in vitro

    Cosmogenic-neutron activation of TeO2 and implications for neutrinoless double-beta decay experiments

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    Flux-averaged cross sections for cosmogenic-neutron activation of natural tellurium were measured using a neutron beam containing neutrons of kinetic energies up to ∼\sim800 MeV, and having an energy spectrum similar to that of cosmic-ray neutrons at sea-level. Analysis of the radioisotopes produced reveals that 110mAg will be a dominant contributor to the cosmogenic-activation background in experiments searching for neutrinoless double-beta decay of 130Te, such as CUORE and SNO+. An estimate of the cosmogenic-activation background in the CUORE experiment has been obtained using the results of this measurement and cross-section measurements of proton activation of tellurium. Additionally, the measured cross sections in this work are also compared with results from semi-empirical cross-section calculations.Comment: 11 pages, 5 figure

    Motor Timing Intraindividual Variability in Amnestic Mild Cognitive Impairment and Cognitively Intact Elders at Genetic Risk for Alzheimer’s Disease

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    Introduction: Intraindividual variability (IIV) in motor performance has been shown to predict future cognitive decline. The apolipoprotein E-epsilon 4 (APOE-ε4) allele is also a well-established risk factor for memory decline. Here, we present novel findings examining the influence of the APOE-ε4 allele on the performance of asymptomatic healthy elders in comparison to individuals with amnestic MCI (aMCI) on a fine motor synchronization, paced finger-tapping task (PFTT). Method: Two Alzheimer’s disease (AD) risk groups, individuals with aMCI (n = 24) and cognitively intact APOE-ε4 carriers (n = 41), and a control group consisting of cognitively intact APOE-ε4 noncarriers (n = 65) completed the Rey Auditory Verbal Learning Test and the PFTT, which requires index finger tapping in synchrony with a visual stimulus (interstimulus interval = 333 ms). Results: Motor timing IIV, as reflected by the standard deviation of the intertap interval (ITI), was greater in the aMCI group than in the two groups of cognitively intact elders; in contrast, all three groups had statistically equivalent mean ITI. No significant IIV differences were observed between the asymptomatic APOE-ε4 carriers and noncarriers. Poorer episodic memory performance was associated with greater IIV, particularly in the aMCI group. Conclusions: Results suggest that increased IIV on a fine motor synchronization task is apparent in aMCI. This IIV measure was not sensitive in discriminating older asymptomatic individuals at genetic risk for AD from those without such a genetic risk. In contrast, episodic memory performance, a well-established predictor of cognitive decline in preclinical AD, was able to distinguish between the two cognitively intact groups based on genetic risk

    Aerodynamic Parameter Estimation for the X-43A (Hyper-X) from Flight Data

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    Aerodynamic parameters were estimated based on flight data from the third flight of the X-43A hypersonic research vehicle, also called Hyper-X. Maneuvers were flown using multiple orthogonal phase-optimized sweep inputs applied as simultaneous control surface perturbations at Mach 8, 7, 6, 5, 4, and 3 during the vehicle descent. Aerodynamic parameters, consisting of non-dimensional longitudinal and lateral stability and control derivatives, were estimated from flight data at each Mach number. Multi-step inputs at nearly the same flight conditions were also flown to assess the prediction capability of the identified models. Prediction errors were found to be comparable in magnitude to the modeling errors, which indicates accurate modeling. Aerodynamic parameter estimates were plotted as a function of Mach number, and compared with estimates from the pre-flight aerodynamic database, which was based on wind-tunnel tests and computational fluid dynamics. Agreement between flight estimates and values computed from the aerodynamic database was excellent overall

    The Effect of an Oxytocin Receptor Antagonist (Retosiban, GSK221149A) on the Response of Human Myometrial Explants to Prolonged Mechanical Stretch.

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    Multiple pregnancy is a major cause of spontaneous preterm birth, which is related to uterine overdistention. The objective of this study was to determine whether an oxytocin receptor antagonist, retosiban (GSK221149A), inhibited the procontractile effect of stretch on human myometrium. Myometrial biopsies were obtained at term planned cesarean delivery (n = 12). Each biopsy specimen was dissected into 8 strips that were exposed in pairs to low or high stretch (0.6 or 2.4 g) in the presence of retosiban (1 μM) or vehicle (dimethylsulfoxide) for 24 hours. Subsequently, we analyzed the contractile responses to KCl and oxytocin in the absence of retosiban. We found that incubation under high stretch in vehicle alone increased the response of myometrial explants to both KCl (P = .007) and oxytocin (P = .01). However, there was no statistically significant effect of stretch when explants were incubated with retosiban (P = .3 and .2, respectively). Incubation with retosiban in low stretch had no statistically significant effect on the response to either KCl or oxytocin (P = .8 and >.9, respectively). Incubation with retosiban in high stretch resulted in a statistically significant reduction (median fold change, interquartile range, P) in the response to both KCl (0.74, 0.60-1.03, P = .046) and oxytocin (0.71, 0.53-0.91, P = .008). The greater the effect of stretch on explants from a given patient, the greater was the inhibitory effect of retosiban (r = -0.65, P = .02 for KCl and r= -0.73, P = .007 for oxytocin). These results suggest that retosiban prevented stretch-induced stimulation of human myometrial contractility. Retosiban treatment is a potential approach for preventing preterm birth in multiple pregnancy.This is the author accepted manuscript. The final version is available from the Endocrine Society via http://dx.doi.org/10.1210/en.2015-137

    Non-equilibrium dynamics and floral trait interactions shape extant angiosperm diversity.

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    Why are some traits and trait combinations exceptionally common across the tree of life, whereas others are vanishingly rare? The distribution of trait diversity across a clade at any time depends on the ancestral state of the clade, the rate at which new phenotypes evolve, the differences in speciation and extinction rates across lineages, and whether an equilibrium has been reached. Here we examine the role of transition rates, differential diversification (speciation minus extinction) and non-equilibrium dynamics on the evolutionary history of angiosperms, a clade well known for the abundance of some trait combinations and the rarity of others. Our analysis reveals that three character states (corolla present, bilateral symmetry, reduced stamen number) act synergistically as a key innovation, doubling diversification rates for lineages in which this combination occurs. However, this combination is currently less common than predicted at equilibrium because the individual characters evolve infrequently. Simulations suggest that angiosperms will remain far from the equilibrium frequencies of character states well into the future. Such non-equilibrium dynamics may be common when major innovations evolve rarely, allowing lineages with ancestral forms to persist, and even outnumber those with diversification-enhancing states, for tens of millions of years

    Corn Seed Spacing Uniformity as Affected by Seed Tube Condition

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    Variation in corn seed spacing from a John Deere MaxEmergeTM Plus Vacumeter planter was evaluated on the University of Nebraska Planter Test Stand in a laboratory setting for two seed tube conditions (new or worn) with two examples of corn seed shape (round or flat). Seed spacing uniformity was measured using three seed spacing uniformity parameters: Coefficient of Precision (CP3), ISO Multiples index, and ISO Miss index. Differences were detected in all three seed spacing uniformity parameters due to the seed tube condition. The new seed tubes had better seed spacing uniformity than the worn seed tubes, within each example of the seed shapes (round or flat) used in this experiment. For the seed used in this experiment, the round corn seed had better seed spacing uniformity than the flat corn seed, within each of the seed tube conditions (new or worn). A recommended schedule for seed tube replacement to maintain seed spacing uniformity has not been developed, and more research in this area is needed. Currently, sugarbeet growers in western Nebraska use one of three options: a) test one of their seed tubes on a good planter test stand every year before sugarbeet planting season and replace all tubes when results indicate it will improve seed spacing uniformity to the desired level; b) feel the inside front surface of the seed tube every year before sugarbeet planting season and change seed tubes when the feel of the surface changes from a slick plastic to a very fine sandpaper; or c) replace seed tubes before sugarbeet planting season when they have planted over approximately 150 acres of corn per planter row with their current seed tubes

    The Assessment of Physical Risk Taking: Preliminary Construct Validation of a New Behavioral Measure

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    Risk taking is a complex heterogeneous construct that has proven difficult to assess, especially when using behavioral tasks. We present an exploratory investigation of new measure–the Assessment of Physical Risk Taking (APRT). APRT produces a variety of different outcome scores and is designed as a comprehensive assessment of the probability of success and failure, and magnitude of reward and punishment of different types of simulated physically risky behaviors. Effects observed on the simulated behaviors are hypothesized to reflect similar effects on real world physical risks. Participants (N = 224) completed APRT in a laboratory setting, half of whom had a 1.5 s delay interposed between button presses. Exploratory analyses utilizing generalized estimating equations examined the main effects and two-way interactions among five within-subject factors, as well as two-way interactions between the within-subject factors and Delay across four APRT outcome scores. Results indicated that Injury Magnitude and Injury Probability exerted stronger effects than any of the other independent variables. Participants also completed several self-report measures of risk taking and associated constructs (e.g., sensation seeking), which were correlated with APRT scores to assess the preliminary convergent and divergent validity of the new measure. After correcting for multiple comparisons, APRT scores correlated with self-reported risk taking in thrilling, physically dangerous activities specifically, but only for those who did not have a delay between APRT responses. This promising exploratory investigation highlights the need for future studies comparing APRT to other behavioral risk taking tasks, examining the robustness of the observed APRT effects, and investigating how APRT may predict real-world physical risk taking

    The Registration Continuum in Personality Disorder Studies: Theory, Rationale, And Template

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    Registration is a tool to increase the rigor of personality disorder research and its ability to reduce human suffering through improving people\u27s lives. This article details the problems that exist without registrations, which revolve around a study\u27s outcomes\u27 dependence on the data rather than on the theory being tested. Registrations exist on a continuum underpinned by bipolar timing and unipolar disclosure dimensions, the latter of which poses myriad points of decisions for researchers to register. The registration process provides memory aids and guideposts for researchers through the course of a study, transparently maintains public trust in the scientific enterprise, and preserves the severity of the tests used in the study. This article provides a template for personality disorder researchers to consider and examples of how researchers can use registered flexibility to plan for contingencies that might arise during a study. It also addresses challenges in evaluating registrations and implementing registration in a research workflow
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