13 research outputs found

    Lidar technology measurements and technology: Report of panel

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    Lidar is ready to make an important contribution to tropospheric chemistry research with a variety of spaceborne measurements that complement the measurements from passive instruments. Lidar can now be considered for near-term and far-term space missions dealing with a number of scientifically important issues in tropospheric chemistry. The evolution in the lidar missions from space are addressed and details of these missions are given. The laser availability for space missions based upon the technical data is assessed

    Directly probing the mechanical properties of the spindle and its matrix

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    © The Authors, 2010. This article is distributed under the terms of the Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License. The definitive version was published in Journal of Cell Biology 188 (2010): 481-489, doi:10.1083/jcb.200907110.Several recent models for spindle length regulation propose an elastic pole to pole spindle matrix that is sufficiently strong to bear or antagonize forces generated by microtubules and microtubule motors. We tested this hypothesis using microneedles to skewer metaphase spindles in Xenopus laevis egg extracts. Microneedle tips inserted into a spindle just outside the metaphase plate resulted in spindle movement along the interpolar axis at a velocity slightly slower than microtubule poleward flux, bringing the nearest pole toward the needle. Spindle velocity decreased near the pole, which often split apart slowly, eventually letting the spindle move completely off the needle. When two needles were inserted on either side of the metaphase plate and rapidly moved apart, there was minimal spindle deformation until they reached the poles. In contrast, needle separation in the equatorial direction rapidly increased spindle width as constant length spindle fibers pulled the poles together. These observations indicate that an isotropic spindle matrix does not make a significant mechanical contribution to metaphase spindle length determination.This work was supported by National Institute of General Medicine grants to J.C. Gatlin (F32GM080049) and E.D. Salmon (GM24364). T.J. Mitchison was funded by a grant from the National Cancer Institute (CA078048-09)

    Reproducibility of the internal load and performance-based responses to simulated amateur boxing

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    This is a non-final version of an article published in final form in Thomson, E., & Lamb, K. (2017). Reproducibility of the internal load and performance-based responses to simulated amateur boxing. Journal of Strength and Conditioning Research, 31(12), 3396-3402. DOI: 10.1519/JSC.0000000000001749The aim of this study was to examine the reproducibility of the internal load and performance-based responses to repeated bouts of a three-round amateur boxing simulation protocol (BOXFIT). Twenty-eight amateur boxers completed two familiarisation trials before performing two complete trials of the BOXFIT, separated by 4-7 days. To characterise the internal load, mean (HRmean) and peak (HRpeak) heart rate, breath-by-breath oxygen uptake (V ̇O2), aerobic energy expenditure (EEaer), excess carbon dioxide production (CO2excess) and ratings of perceived exertion (RPE) were recorded throughout each round and blood lactate determined post-BOXFIT. Additionally, an indication of the performance-based demands of the BOXFIT was provided by a measure of acceleration of the punches thrown in each round. Analysis revealed there were no significant differences (P > 0.05) between repeated trials in any round for all dependent measures. The typical error (coefficient variation %) for all but one marker of internal load (CO2excess) was 1.2 – 16.5% and reflected a consistency that was sufficient for the detection of moderate changes in variables owing to an intervention. The reproducibility of the punch accelerations was high (CV% range = 2.1 – 2.7%). In general, these findings suggest that the internal load and performance-based efforts recorded during the BOXFIT are reproducible and thereby offers practitioners a method by which meaningful changes impacting on performance could be identified
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