Reliability of adjustment instrument in grade three

Thesis (Ed.M.)--Boston Universit

Serotonergic And Hypocretinergic Systems Modulate Ventilation And Hypercapnic Ventilatory Responses

Thesis (Ph.D.) University of Alaska Fairbanks, 2009Serotonergic (5-HT) cells of the medullary raphe are putative central chemoreceptors, one of multiple chemoreceptive sites in the brainstem that interact to produce the respiratory chemoreflex. This role is debated, and the importance of 5-HT neurons as chemoreceptors in relatively intact systems is unclear. The main focus of this dissertation is to provide further physiological evidence for the involvement and modulation of 5-HT neurons in CO2 chemosensitivity. This is of interest as a large number of Sudden Infant Death Syndrome (SIDS) cases report dysfunction in the 5-HT system, and CO2 may be an exogenous stressor leading to SIDS when in combination with this underlying vulnerability. Also, since SIDS occurs primarily during sleep, I also focus on the potential functional interaction between the 5-HT and hypocretinergic systems, as hypocretins play a role in arousal and also potentially in chemosensitivity. I confirm the hypothesis that the serotonergic and hypocretinergic systems modulate ventilation and hypercapnic ventilatory responses. Using the in situ preparation derived from juvenile rats and the in vitro medullary slice preparation from mice, I verify that 5-HT neurons are critical in generating a response to CO2, primarily via facilitation of the respiratory rhythm through 5-HT2 receptors. I also find evidence to support the hypothesis that hypocretins play a significant role in the neuroventilatory response to CO2 through activation of hypocretin receptors type 1. By comparing results from rhythmic medullary slice preparations from wildtype (normal 5-HT function) and Lmx1bf/f/p (lack central 5-HT neurons) neonatal mice, I attempt to identify whether changes in hypoglossal nerve output in response to acidosis are affected by hypocretin receptors, and whether this is dependent on the presence of 5-HT neurons. Frequency results from such studies are inconclusive; however, hypocretins do appear to mediate the burst duration response via serotonergic mechanisms. I also find that hypocretins facilitate baseline neural ventilatory output in part through 5-HT neurons. Thus, both the 5-HT and hypocretinergic systems are involved in modulating ventilation and hypercapnic ventilatory responses

Thermovacuum forming plastics for artistic endeavors

None provided

A longitudinal study to determine the stanine stability of a group's test-score performance in the elementary school

Thesis (Ed.D.)--Boston Universit

Laser Guide Star Adaptive Optics Integral Field Spectroscopy of a Tightly Collimated Bipolar Jet from the Herbig Ae star LkHa 233

We have used the integral field spectrograph OSIRIS and laser guide star adaptive optics at Keck Observatory to obtain high angular resolution (0.06"), moderate spectral resolution (R ~ 3800) images of the bipolar jet from the Herbig Ae star LkHa 233, seen in near-IR [Fe II] emission at 1.600 & 1.644 microns. This jet is narrow and tightly collimated, with an opening angle of only 9 degrees, and has an average radial velocity of ~ 100 km/s. The jet and counterjet are asymmetric, with the red-shifted jet much clumpier than its counterpart at the angular resolution of our observations. The observed properties are in general similar to jets seen around T Tauri stars, though it has a relatively large mass flux of (1.2e-7 +- 0.3e-7) M_sun/year, near the high end of the observed mass flux range around T Tauri stars. We also spatially resolve an inclined circumstellar disk around LkHa 233, which obscures the star from direct view. By comparison with numerical radiative transfer disk models, we estimate the disk midplane to be inclined i = 65 +- 5 degrees relative to the plane of the sky. Since the star is seen only in scattered light at near-infrared wavelengths, we detect only a small fraction of its intrinsic flux. Because previous estimates of its stellar properties did not account for this, either LkHa 233 must be located closer than the previously believed, or its true luminosity must be greater than previously supposed, consistent with its being a ~4 M_sun star near the stellar birthline.Comment: Accepted for publication in the Ap

Motor-starting characteristics of two inductor alternators

Motor starting characteristics of two inductor alternator

Spiralling out of control: 3D hydrodynamical modelling of the colliding winds in η \eta\thinspaceCarinae

Three dimensional (3D) adaptive-mesh refinement (AMR) hydrodynamical simulations of the wind-wind collision between the enigmatic super-massive star \etacar and its mysterious companion star are presented which include radiative driving of the stellar winds, gravity, optically-thin radiative cooling, and orbital motion. Simulations with static stars with a periastron passage separation reveal that the preshock companion star's wind speed is sufficiently reduced that radiative cooling in the postshock gas becomes important, permitting the runaway growth of non-linear thin shell (NTSI) instabilities which massively distort the WCR. However, large-scale simulations which include the orbital motion of the stars, show that orbital motion reduces the impact of radiative inhibition, and thus increases the acquired preshock velocities. As such, the postshock gas temperature and cooling time see a commensurate increase, and sufficient gas pressure is preserved to stabilize the WCR against catastrophic instability growth. We then compute synthetic X-ray spectra and lightcurves and find that, compared to previous models, the X-ray spectra agree much better with {\it XMM-Newton} observations just prior to periastron. The narrow width of the 2009 X-ray minimum can also be reproduced. However, the models fail to reproduce the extended X-ray mimimum from previous cycles. We conclude that the key to explaining the extended X-ray minimum is the rate of cooling of the companion star's postshock wind. If cooling is rapid then powerful NTSIs will heavily disrupt the WCR. Radiative inhibition of the companion star's preshock wind, albeit with a stronger radiation-wind coupling than explored in this work, could be an effective trigger.Comment: 25 pages, 20 figures, accepted for publication in Ap

Investigation of laser frequency stabilization

Frequency stabilization of far infrared lase