Doppler Tomography of Dwarf Nova IY UMa during Quiescence

Quiescent Doppler tomography of the newly discovered deeply-eclipsing SU UMa system IY UMa reveals properties of the region where the accretion stream from the donor impacts the edge of the disc. A very strong bright spot is produced and the Keplerian disc emission in the impact region is disrupted or obscured. The differing properties of Halpha, Hbeta and He I emission will allow physical parameters of the converging flow region to be studied.Comment: 6 pages, 5 figures. To appear in Proceedings of Astro-Tomography Workshop, Brussels, July 2000, Eds. H. Boffin, D. Steeghs, Springer-Verlag Lecture Notes in Physic

Calibration Transients In LIGO Detectors

This dissertation describes a novel method of analyzing fluctuations in the time-dependent calibration models of the LIGO interferometers to estimate their effect on strain reconstruction for gravitational-wave detections. The time-dependence of the calibration model of each detector is tracked with a set of parameters which are continuously measured while the interferometers are operating. These parameters track slow variations in the sensing function of the detectors as well as the actuators that hold the detectors in an operational state. The time-dependent parameter data during the second observation run (O2 [November 30, 2016 16:00 UTC to August 25, 2017 22:00:00 UTC]) and the first epoch of the third observation run (O3a [April 1, 2019 15:00 UTC to October 1, 2019 15:00 UTC]) were combed for significant fluctuations. A modified z-score was used as a standardized metric to identify and sort time segments which correspond to noise transients in the time-dependent calibration parameters for both detectors. The results of our search through O2 data from the LIGO Hanford Observatory (LHO) identified a set of relatively few noise transients all with negligible statistical significance, demonstrating that the behavior of the time-dependent calibration parameters at LHO were largely consistent with Gaussian noise on 30-minute or less time scales. Our search through O2 data from the LIGO Livingston Observatory (LLO) showed similar results for the parameters that track variations in actuation. Likewise, the sensing function parameters were mostly consistent with Gaussian noise as well; however, our search identified a small set of statistically significant noise transients. None of which were coincident with gravitational-wave signals, and the most significant of which were estimated to momentarily increase the strain reconstruction 1-sigma uncertainty from 1% to 3% in the regime of the interferometers\u27 most sensitive frequency band (150Hz). Like the O2 results, analysis of O3a data revealed that all the time-dependent calibration parameters at each detector were mostly consistent with Gaussian noise on 30-minute or less time scales. Our results demonstrate that overall, the time-dependent calibration parameters experienced very few significant fluctuations throughout O2 and O3a, and even largest transient we found would have minimal impact on gravitational-wave measurements

The application of deep eutectic solvent ionic liquids for environmentally-friendly dissolution and recovery of precious metals

publisher: Elsevier articletitle: The application of deep eutectic solvent ionic liquids for environmentally-friendly dissolution and recovery of precious metals journaltitle: Minerals Engineering articlelink: http://dx.doi.org/10.1016/j.mineng.2015.09.026 content_type: article copyright: Copyright © 2015 The Authors. Published by Elsevier Ltd.© 2015 Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)

Jet measurements at DO using a KT algorithm

DO has implemented and calibrated a KT jet algorithm for the first time in a ppbar collider. We present two results based on 1992-1996 data which were recently published: the subjet multiplicity in quark and gluon jets and the central inclusive jet cross section. The measured ratio between subjet multiplicities in gluon and quark jets is consistent with theoretical predictions and previous experimental values. NLO pQCD predictions of the KT inclusive jet cross section agree with the DO measurement, although marginally in the low pT range. We also present a preliminary measurement of thrust cross sections, which indicates the need to include higher than alpha_s^3 terms and resumation in the theoretical calculations.Comment: 8 pages, 10 figures, presented at the High-Energy Physics International Conference in Quantum Chromodynamics, Montpellier, France, July 2-9th 2002. To be published in Nuclear Physics

Analysis of 3D-printed metal for rapid-prototyped reflective terahertz optics

We explore the potential of 3D metal printing to realize complex conductive terahertz devices. Factors impacting performance such as printing resolution, surface roughness, oxidation, and material loss are investigated via analytical, numerical, and experimental approaches. The high degree of control offered by a 3D-printed topology is exploited to realize a zone plate operating at 530 GHz. Reflection efficiency at this frequency is found to be over 90%. The high-performance of this preliminary device suggest that 3D metal printing can play a strong role in guided-wave and general beam control devices in the terahertz range.Comment: 13 pages, 6 figures, submitted to Optics Expres

Kcne4 deletion sex- and age-specifically impairs cardiac repolarization in mice.

Myocardial repolarization capacity varies with sex, age, and pathology; the molecular basis for this variation is incompletely understood. Here, we show that the transcript for KCNE4, a voltage-gated potassium (Kv) channel β subunit associated with human atrial fibrillation, was 8-fold more highly expressed in the male left ventricle compared with females in young adult C57BL/6 mice (P < 0.05). Similarly, Kv current density was 25% greater in ventricular myocytes from young adult males (P < 0.05). Germ-line Kcne4 deletion eliminated the sex-specific Kv current disparity by diminishing ventricular fast transient outward current (Ito,f) and slowly activating K(+) current (IK,slow1). Kcne4 deletion also reduced Kv currents in male mouse atrial myocytes, by >45% (P < 0.001). As we previously found for Kv4.2 (which generates mouse Ito,f), heterologously expressed KCNE4 functionally regulated Kv1.5 (the Kv α subunit that generates IKslow1 in mice). Of note, in postmenopausal female mice, ventricular repolarization was impaired by Kcne4 deletion, and ventricular Kcne4 expression increased to match that of males. Moreover, castration diminished male ventricular Kcne4 expression 2.8-fold, whereas 5α-dihydrotestosterone (DHT) implants in castrated mice increased Kcne4 expression >3-fold (P = 0.01) to match noncastrated levels. KCNE4 is thereby shown to be a DHT-regulated determinant of cardiac excitability and a molecular substrate for sex- and age-dependent cardiac arrhythmogenesis

Abnormal infant islet morphology precedes insulin resistance in PCOS-like monkeys.

Polycystic ovary syndrome (PCOS) is prevalent in reproductive-aged women and confounded by metabolic morbidities, including insulin resistance and type 2 diabetes. Although the etiology of PCOS is undefined, contribution of prenatal androgen (PA) exposure has been proposed in a rhesus monkey model as premenopausal PA female adults have PCOS-like phenotypes in addition to insulin resistance and decreased glucose tolerance. PA female infants exhibit relative hyperinsulinemia, suggesting prenatal sequelae of androgen excess on glucose metabolism and an antecedent to future metabolic disease. We assessed consequences of PA exposure on pancreatic islet morphology to identify evidence of programming on islet development. Islet counts and size were quantified and correlated with data from intravenous glucose tolerance tests (ivGTT) obtained from dams and their offspring. Average islet size was decreased in PA female infants along with corresponding increases in islet number, while islet fractional area was preserved. Infants also demonstrated an increase in both the proliferation marker Ki67 within islets and the beta to alpha cell ratio suggestive of enhanced beta cell expansion. PA adult females have reduced proportion of small islets without changes in proliferative or apoptotic markers, or in beta to alpha cell ratios. Together, these data suggest in utero androgen excess combined with mild maternal glucose intolerance alter infant and adult islet morphology, implicating deviant islet development. Marked infant, but subtle adult, morphological differences provide evidence of islet post-natal plasticity in adapting to changing physiologic demands: from insulin sensitivity and relative hypersecretion to insulin resistance and diminished insulin response to glucose in the mature PCOS-like phenotype

Receipt, 22 December 1866

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