378 research outputs found

    Loran-C expansion: Impact on precise time/time interval

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    On 16 May 1974, it was announced that Loran-C was chosen as the navigation system to serve the U. S. Coastal Confluence Zone. At the present time, reliable CONUS Loran-C groundwave timing coverage extends westward only about as far as Boulder, CO. The groundwave hyperbolic and timing coverage which will result from the planned CONUS expansion are illustrated. Time frames are provided. A status report on the planned reduction in Loran-C PTTI tolerances is presented

    THE VALUE OF PRECONDITIONING PROGRAMS IN BEEF PRODUCTION SYSTEMS

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    Net returns to feeding were calculated for preconditioning. The added value to cattle feeders, without accounting for death loss, from purchasing preconiditioned calves over calves of unknown origin is 46.83/headand46.83/head and 49.54/head for the CPH and GT calves, respectively. As a result, a feedlot operator could pay 8.50/cwtand8.50/cwt and 9.00/cwt more per 550 pound CPH and GT feeder calves, respectively, and still maintain the same level of profit.Livestock Production/Industries,

    Gottfried Wilhelm Osann (1833, 1836) on Simultaneous Color Contrast:Translation and Commentary

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    Gottfried Wilhelm Osann (1796–1866) was a German scientist most renowned for his work in chemistry and physics. However, inspired by Goethe’s work on color, he published a paper on simultaneous color contrast in 1833 using a method that is similar to that of later authors: reflection of an achromatic spot from an angled piece of glass. He wrote at least four more papers on color contrasts, in 1836 using essentially the same method as credited to others. We provide a description and translation of Osann’s 1833 paper and the relevant part of his 1836 paper, say why these papers are interesting and important, give some biographical information about Osann, comment on the fate of Osann’s papers, and describe Osann’s other papers on color

    Sensory ERP effects in auditory distraction: did we miss the main event?

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    Event-related potentials (ERPs) offer unique insights into processes related to involuntary attention changes triggered by rare, unpredictably occurring sensory events, that is, distraction. Contrasting ERPs elicited by distracters and frequent standard stimuli in oddball paradigms allowed the formulation of a three-stage model describing distraction-related processing: first, the distracting event is highlighted by a sensory filter. Second, attention is oriented towards the event, and finally, the task-optimal attention set is restored, or task priorities are changed. Although this model summarizes how distracting stimulus information is processed, not much is known about the cost of taking this exceptional route of processing. The present study demonstrates the impact of distraction on sensory processing. Participants performed a Go/NoGo tone-duration discrimination task, with infrequent pitch distracters. In the two parts of the experiment the duration-response mapping was reversed. Contrasts of distracter and standard ERPs revealed higher P3a- and reorienting negativity amplitudes for short than for long tones, independently from response type. To understand the cause of these asymmetries, short vs. long ERP contrasts were calculated. The ERP pattern showed that short standards elicited an attention-dependent offset response, which was abolished for short distracters. That is, the apparent P3a- and RON enhancements were caused by the removal of a task-related attentional sensory enhancement. This shows that the disruption of task-optimal attention set precedes the elicitation of the P3a, which suggests that P3a does not reflect a process driving the initial distraction-related attention change

    Zur Theorie des Dellmann'schen Elektrometers

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    Tractor hydraulic power data acquisition system

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    Tractor hydraulic power is used on a wide range of agricultural implements; however, the availability of operational hydraulic data at points other than full engine throttle position is limited. Operators could utilize this hydraulic data to maximize field efficiency and minimize machinery costs when determining suitable machinery for field operations. A field usable hydraulic test apparatus capable of measuring tractor hydraulic pressure and flow rate data was developed. The goal of this study was to determine if a hydraulic flow and pressure measurement device could be installed on the rear of a tractor to provide implement hydraulic power consumption at different hydraulic hose orientations. The measurement system installed allowed hydraulic lines from the tractor hydraulic remote ports to be attached to the flowmeter and pressure sensors at multiple angles of 0°, 45°, and 90° in different configuration layouts. Tests were performed at different flows and pressures for each hose configuration. The pressures were compared across configurations to a base line reading from a hydraulic pressure and flow rate measurement apparatus used by the Nebraska Tractor Test Laboratory (NTTL). Pressure deviations from the base line were small and ranged between 10.56 kPa and 32.2 kPa. Flow rate differences (\u3c167 mL min–1) were determined to be negligible (\u3c0.5%). Calculated power differences (\u3c33 W) were less than 1% full scale power measured. This small power loss suggested that using the hydraulic measurement apparatus developed as part of this study would enable accurate measurements of tractor hydraulic power provided to implements regardless of hydraulic hose bend angles

    Natural products from resurrection plants:Potential for medical applications

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    AbstractResurrection species are a group of land plants that can tolerate extreme desiccation of their vegetative tissues during harsh drought stress, and still quickly – often within hours – regain normal physiological and metabolic functions following rehydration. At the molecular level, this desiccation tolerance is attributed to basal cellular mechanisms including the constitutive expression of stress-associated genes and high levels of protective metabolites present already in the absence of stress, as well as to transcriptome and metabolome reconfigurations rapidly occurring during the initial phases of drought stress. Parts of this response are conferred by unique metabolites, including a diverse array of sugars, phenolic compounds, and polyols, some of which accumulate to high concentrations within the plant cell. In addition to drought stress, these metabolites are proposed to contribute to the protection against other abiotic stresses and to an increased oxidative stress tolerance. Recently, extracts of resurrection species and particular secondary metabolites therein were reported to display biological activities of importance to medicine, with e.g. antibacterial, anticancer, antifungal, and antiviral activities, rendering them possible candidates for the development of novel drug substances as well as for cosmetics. Herein, we provide an overview of the metabolite composition of resurrection species, summarize the latest reports related to the use of natural products from resurrection plants, and outline their potential for medical applications

    On the Role of Attention in Binocular Rivalry: Electrophysiological Evidence

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    During binocular rivalry visual consciousness fluctuates between two dissimilar monocular images. We investigated the role of attention in this phenomenon by comparing event-related potentials (ERPs) when binocular-rivalry stimuli were attended with when they were unattended. Stimuli were dichoptic, orthogonal gratings that yielded binocular rivalry and dioptic, identically oriented gratings that yielded binocular fusion. Events were all possible orthogonal changes in orientation of one or both gratings. We had two attention conditions: In the attend-to-grating condition, participants had to report changes in perceived orientation, focussing their attention on the gratings. In the attend-to-fixation condition participants had to report changes in a central fixation target, taking attention away from the gratings. We found, surprisingly, that attending to rival gratings yielded a smaller ERP component (the N1, from 160–210 ms) than attending to the fixation target. To explain this paradoxical effect of attention, we propose that rivalry occurs in the attend-to-fixation condition (we found an ERP signature of rivalry in the form of a sustained negativity from 210–300 ms) but that the mechanism processing the stimulus changes is more adapted in the attend-to-grating condition than in the attend-to-fixation condition. This is consistent with the theory that adaptation gives rise to changes of visual consciousness during binocular rivalry
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