Study of basic bio-electrochemistry Sixth monthly progress report, 1-31 Aug. 1963

Contribution of hydrogen peroxide to electrode reaction in electrochemical cell by considering effect of catalyst on cell curren

Comparing key compositional indicators in Jupiter with those in extra-solar giant planets

Spectroscopic transiting observations of the atmospheres of hot Jupiters around other stars, first with Hubble Space Telescope and then Spitzer, opened the door to compositional studies of exoplanets. The James Webb Space Telescope will provide such a profound improvement in signal-to-noise ratio that it will enable detailed analysis of molecular abundances, including but not limited to determining abundances of all the major carbon- and oxygen-bearing species in hot Jupiter atmospheres. This will allow determination of the carbon-to-oxygen ratio, an essential number for planet formation models and a motivating goal of the Juno mission currently around JupiterComment: Submitted to the Astro2020 Decadal Survey as a white paper; thematic areas "Planetary Systems" and "Star and Planet Formation

An architecture for IEEE 802.16 MAC scheduler design

Copyright © 2007 IEEEThe scheduling algorithm for IEEE 802.16 broadband wireless access system has been left open in the standard. In this paper, we consider three criteria that we have identified as important criteria for an 802.16 scheduler: Service Type differentiation, dynamic sub-frame partition and Subscriber Station differentiation. We investigate the scheduler design from a general perspective, based on these three criteria

The Solar Twin Planet Search II. A Jupiter twin around a solar twin

Through our HARPS radial velocity survey for planets around solar twin stars, we have identified a promising Jupiter twin candidate around the star HIP11915. We characterize this Keplerian signal and investigate its potential origins in stellar activity. Our analysis indicates that HIP11915 hosts a Jupiter-mass planet with a 3800-day orbital period and low eccentricity. Although we cannot definitively rule out an activity cycle interpretation, we find that a planet interpretation is more likely based on a joint analysis of RV and activity index data. The challenges of long-period radial velocity signals addressed in this paper are critical for the ongoing discovery of Jupiter-like exoplanets. If planetary in nature, the signal investigated here represents a very close analog to the solar system in terms of both Sun-like host star and Jupiter-like planet.Comment: 8 pages, 5 figures; A&A accepted; typos corrected in this versio

Evolution of the fishtail-effect in pure and Ag-doped MG-YBCO

We report on magnetic measurements carried out in a textured YBa$_2$Cu$_3$O$_{7-\delta}$ and YBa$_2$(Cu$_{1-x}$Ag$_x$)$_3$O$_{7-\delta}$ (at $x \approx$ 0.02) crystals. The so-called fishtail-effect (FE) or second magnetization peak has been observed in a wide temperature range 0.4~$<T/T_c<$~0.8 for $\textbf{H}\parallel c$. The origin of the FE arises for the competition between surface barrier and bulk pinning. This is confirmed in a non-monotonically behavior of the relaxation rate $R$. The value $H_{max}$ for Ag-doped crystals is larger than for the pure one due to the presence of additional pinning centers, above all on silver atoms.Comment: 6 pages, 6 figure

18 Sco: a solar twin rich in refractory and neutron-capture elements. Implications for chemical tagging

We study with unprecedented detail the chemical composition and stellar parameters of the solar twin 18 Sco in a strictly differential sense relative to the Sun. Our study is mainly based on high resolution (R ~ 110 000) high S/N (800-1000) VLT UVES spectra, which allow us to achieve a precision of about 0.005 dex in differential abundances. The effective temperature and surface gravity of 18 Sco are Teff = 5823+/-6 K and log g = 4.45+/-0.02 dex, i.e., 18 Sco is 46+/-6 K hotter than the Sun and log g is 0.01+/-0.02 dex higher. Its metallicity is [Fe/H] = 0.054+/-0.005 dex and its microturbulence velocity is +0.02+/-0.01 km/s higher than solar. Our precise stellar parameters and differential isochrone analysis show that 18 Sco has a mass of 1.04+/-0.02M_Sun and that it is ~1.6 Gyr younger than the Sun. We use precise HARPS radial velocities to search for planets, but none were detected. The chemical abundance pattern of 18 Sco displays a clear trend with condensation temperature, showing thus higher abundances of refractories in 18 Sco than in the Sun. Intriguingly, there are enhancements in the neutron-capture elements relative to the Sun. Despite the small element-to-element abundance differences among nearby n-capture elements (~0.02 dex), we successfully reproduce the r-process pattern in the solar system. This is independent evidence for the universality of the r-process. Our results have important implications for chemical tagging in our Galaxy and nucleosynthesis in general.Comment: ApJ, in pres

A Simple Targeting Procedure for Lunar Trans-Earth Injection

A simple targeting algorithm for trans-Earth injection is developed. The techniques presented in this paper build on techniques developed for the Apollo program and other lunar and interplanetary missions. Presently, more sophisticated algorithms exist for solving this problem, but the simplicity of this particular algorithm makes it well-suited for on-board use during contingency and abort operations. In order to support a return from any lunar orbit with available fuel on the spacecraft the algorithm chooses between one-, two-, or three-burn return scenarios. The one- and two-burn cases are based on existing theory. For the three-burn case however, the existing theory is modified in order to provide a simple solution. Rather than attempting to create fuel-optimal trajectories, the algorithm presented in this paper focuses on computing a trajectory from low lunar orbit to direct atmospheric Earth entry that does not violate a fuel constraint. The algorithm attempts to use a minimal number of impulses to execute trans-earth injection. The algorithm can also be used to quickly generate good initial guesses for other more sophisticated targeting algorithms that can be used to find minimal fuel trajectories or optimize other parameters. This algorithm has three principle phases. First, an estimate of the hyperbolic excess velocity at the Lunar sphere of influence is generated. Second, a maneuver is computed that will transfer the craft from a lunar circular orbit to the hyperbolic escape asymptote. Finally, the effects of perturbations are eliminated by using linear state transition matrix targeting

Ultrasound diagnosis of endometrial cancer by subjective pattern recognition in women with postmenopausal bleeding: a prospective inter-rater agreement and reliability study

OBJECTIVES: The objective of our study was to assess the inter-rater agreement and reliability of using subjective pattern recognition to diagnose endometrial cancer on ultrasound in women with postmenopausal bleeding. METHODS: This was a prospective cross-sectional study at a gynaecological rapid access clinic, between Oct 2016 - Dec 2017, where consecutive women with postmenopausal bleeding and endometrial thickness of ≥4.5mm on transvaginal ultrasound scan were included. We excluded women on hormone replacement therapy, tamoxifen or with a history of primary gynaecological malignancy. Two raters independently performed ultrasound examinations, blinded to each other's findings, and classified women into having uniformly thickened endometrium, benign polyp or endometrial cancer, by subjective pattern recognition. Inter-rater reliability of the ultrasound diagnoses was assessed by using Cohen's kappa statistics. All women subsequently underwent either outpatient endometrial biopsy, hysteroscopy or hysterectomy. RESULTS: Forty women were included in the study with a median age of 61 (IQR 57-69) and a median endometrial thickness of 11.0mm (IQR 6.2-20.3). Final histological analysis confirmed 16 (40%) women with endometrial cancer, 16 (40%) endometrial polyps, 4 (10%) atrophic endometrium, 3 (7%) proliferative endometrium and 1 (3%) endometrial hyperplasia. Inter-rater agreement for the ultrasound diagnoses of uniformly thickened endometrium, polyp and cancer, were 14/16 (87.5%), 22/30 (73.3%) and 28/34 (82.4%), respectively; the inter-rater reliability was good (κ = 0.69, 95% C.I. 0.49-0.88). When the ultrasound diagnoses were combined as either cancer or no cancer, the inter-rater agreement was 85% and the inter-rater reliability was also good (κ = 0.78, 95% C.I. 0.61-0.95). Rater A correctly identified 14/16 cancers and Rater B identified 15/16. Endometrial cancers were misdiagnosed as benign polyps on ultrasound in two women by Rater A, and in one woman by Rater B. The overall accuracies of Rater A and Rater B in differentiating between benign endometrial pathologies and malignancy were 90% and 85%, respectively. CONCLUSIONS: Our results showed good inter-rater reliability of subjective pattern recognition in diagnosing uniformly thickened endometrium, polyp and cancer on ultrasound in women with postmenopausal bleeding. Our findings should facilitate wider use of subjective pattern recognition in routine clinical practice

A Discontinuous Galerkin Method for Approximating the Stationary Distribution of Stochastic Fluid-Fluid Processes

The stochastic fluid-fluid model (SFFM) is a Markov process {(Xt,Yt,φt),t≥0}, where {φt,t≥0} is a continuous-time Markov chain, the first fluid, {Xt,t≥0}, is a classical stochastic fluid process driven by {φt,t≥0}, and the second fluid, {Yt,t≥0}, is driven by the pair {(Xt,φt),t≥0}. Operator-analytic expressions for the stationary distribution of the SFFM, in terms of the infinitesimal generator of the process {(Xt,φt),t≥0}, are known. However, these operator-analytic expressions do not lend themselves to direct computation. In this paper the discontinuous Galerkin (DG) method is used to construct approximations to these operators, in the form of finite dimensional matrices, to enable computation. The DG approximations are used to construct approximations to the stationary distribution of the SFFM, and results are verified by simulation. The numerics demonstrate that the DG scheme can have a superior rate of convergence compared to other methods