170,267 research outputs found
Detectability of Self-Lensing Supermassive Black Hole Binaries in Quasars
No full text2022Active galactic nuclei (AGN) or quasars are distant and luminous objects thought to be powered accretion into supermassive black holes (SMBHs) whose luminosity rivals that of their local galaxy. Since most galaxies are thought to contain SMBHs and galaxies commonly merge, it is likely that some AGN contain two SMBHs. While a few dual-AGN or supermassive black hole binaries (SMBHB) have been discovered at parsec (pc) and kiloparsec separations, there are currently no unambiguous detection of SMBHBs (Tremblay et al. 2016; Bansal et al. 2017)[1][2]. One promising new detection technique is through gravitational self-lensing events which may be possible with upcoming observing programs. This thesis develops a method to predict the probability that a given SMBHB system will generate a detectable lensing event by varying the geometric parameters defined by gravitational lensing geometry. The probability that a SMBHB is located at a given separation is calculated by comparing timescales of the different phases of the SMBHB’s lifespan with its total lifespan. This is then combined with the lensing probability to create a probability distribution of lensing events at different separations and masses. This paper explores the effects of different parameters on the probability distribution, focusing primarily on the mass of the SMBHB, its separation distance, the inclination of the system, and the mass ratio of the two black holes. The detectable lensing events from each parameter combination are then combined to determine the overall rate of detectable lensing events that could be detected in a given population. A method is developed to predict lensing characteristics of corresponding magnification and orbital period for different system conditions. Combining the observables with the probability function allows the number of lensing events that are likely to be detected by the upcoming Vera C. Rubin observatory to be determined. Based on this study, the Rubin observatory, will detect up to ∼ 1.9 × 104 lensing events over a 10-year period. This methodology can be adapted to the specification of other datasets and is hereby presented to the quasar research community
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Mitomycin C in highly myopic eyes - Author reply
No full textOphthalmology. 2005 Feb;112(2):208-18; discussion 219.
Mitomycin C modulation of corneal wound healing after photorefractive keratectomy in highly myopic eyes.
Gambato C, Ghirlando A, Moretto E, Busato F, Midena E.
SourceRefractive Surgery Service and Antimetabolite Therapy Research Unit, Department of Ophthalmology, University of Padova, Padova, Italy.
Abstract
PURPOSE: To evaluate the role of topical mitomycin C in corneal wound healing (CWH) after photorefractive keratectomy (PRK) in highly myopic eyes.
DESIGN: Prospective, double-masked, randomized clinical trial.
PARTICIPANTS: Seventy-two eyes of 36 patients affected by high (>7 diopters) myopia.
METHODS: In each patient, one eye was randomly assigned to PRK with intraoperative topical 0.02% mitomycin C application, and the fellow eye was treated with a placebo. Postoperatively, mitomycin C-treated eyes received artificial tears (3 times daily, tapered in 3 months), whereas the fellow eye was treated with fluorometholone sodium 2% and artificial tears (3 times daily, tapered in 3 months).
MAIN OUTCOME MEASURES: Uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA), contrast sensitivity, manifest refraction, and biomicroscopy. Contrast sensitivity was determined using the Pelli-Robson chart. Corneal confocal microscopy documented CWH.
RESULTS: Mean follow-up was 18 months (range, 12-36). No side effects or toxic effects were documented. At 12-month follow-up examination, UCVAs (logarithm of the minimum angle of resolution) were 0.4+/-0.48 and 0.5+/-0.53 (P = .03) in mitomycin C-treated eyes and corticosteroid-treated eyes, respectively. At 1 year, corneal haze developed in 20% of corticosteroid-treated eyes, versus 0% of mitomycin C-treated eyes. At 12, 24, and 36 months, corneal confocal microscopy showed activated keratocytes and extracellular matrix significantly more evident in untreated eyes (Ps = 0.004, 0.024, and 0.046, respectively).
CONCLUSION: Topical intraoperative application of 0.02% mitomycin C can reduce haze formation in highly myopic eyes undergoing PRK.
Comment in
Ophthalmology. 2006 Feb;113(2):357; author reply 357-8
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
A Multi-Language Comparison of Influences on Author Verification using Character N-Grams
No full textWe create a new multi-language corpus for author verification based on Wikipedia talkpages, and evaluate the influence that differences in topic and time have on character n-gram author profiles. Topic alignment between two texts is found to increase author verification precision, and an authors writing style is found to change over time, but not more significantly after 3 years than after 1 year.Information ArchitectureWISElectrical Engineering, Mathematics and Computer Scienc
A 0.12mm<sup>2</sup> Wien-Bridge Temperature Sensor with 0.1°C (3σ) Inaccuracy from -40°C to 180°C
No full text Resistor-based temperature sensors can achieve much higher resolution and energy efficiency than conventional BJT-based sensors [1], but they typically occupy more area (> 0.25 mm 2 ) and have lower operating temperatures (le 125 {circ} {C}) [2]-[4]. This work describes a 0.12mm 2 resistor-based sensor that uses a Wien-bridge (WB) filter to achieve 0.1 {circ} {C} (3 sigma) inaccuracy from - 40 {circ} {C} to 180 {circ} {C}. Compared to a state-of-the-art WB sensor [4], it occupies 6 × less area and achieves comparable relative accuracy over a 76% wider operating range. Session 10.3 Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic InstrumentationMicroelectronic
Green Technology Diffusion: A Post-Mortem Analysis of the Eco-Patent Commons
No full textWe revisit the effect of the “Eco-Patent Commons” (EcoPC) on the diffusion of patented environmentally friendly technologies following its discontinuation in 2016, using both participant survey and data analytic evidence. Established in January 2008 by several large multinational companies, the not-for-profit initiative provided royalty-free access to 248 patents covering 94 “green” inventions. Hall and Helmers (2013) suggested that the patents pledged to the commons had the potential to encourage the diffusion of valuable environmentally friendly technologies. Our updated results now show that the commons did not increase the diffusion of pledged inventions, and that the EcoPC suffered from several structural and organizational issues. Our findings have implications for the effectiveness of patent commons in enabling the diffusion of patented technologies more broadly
Assessing the Effectiveness of the Eco-Patent Commons. A Post-mortem Analysis
No full textThe authors revisit the effect of the “Eco-Patent Commons” (EcoPC) on the diffusion of patented environmentally friendly technologies following its discontinuation in 2016. Established in January 2008 by several large multinational companies, the not-for-profit initiative provided royalty-free access to 248 patents covering 94 “green” inventions. In previous work, Bronwyn Hall and Christian Helmers (2013) suggested that the patents pledged to the commons had the potential to encourage the diffusion of valuable environmentally friendly technologies. The updated results in this paper now show that the commons did not increase the diffusion of pledged inventions, and that the EcoPC suffered from a number of structural and organizational issues. The authors hope these findings will inform future efforts to make environmentally friendly technologies more broadly available for use
Mobile Press-Register sleeve MP0072490
No full textAlabama Welcome Center, manager Thyra Cash with Paul C. Hargrave Sr., wife Laura, and Jamacia Hargrave from Louisiana / Helmers families (2) and Matherne family of Louisiana on way to Gulf Shores / (Alabama Mississippi Welcome Center, I-10
A ±25A Versatile Shunt-Based Current Sensor with 10kHz Bandwidth and ±0.25% Gain Error from -40°C to 85°C Using 2-Current Calibration
No full textAccurate current sensing is critical in many industrial applications, such as battery management and motor control. Precise shunt-based current sensors have been reported with gain errors of less than 1% over the industrial temperature range (-40°C to 85°C) [1]–[4]. However, since they are intended for coulomb counting, their bandwidth is limited to a few tens of Hz, making them unsuitable for battery impedance or motor-current sensing. This paper presents a current sensor with a wide (10kHz) bandwidth and a tunable temperature compensation scheme (TCS), which allows it to be flexibly used with different types of shunts while maintaining high accuracy. A low-cost room-temperature calibration scheme is proposed to optimize gain flatness over temperature by exploiting the shunt's self-heating at large currents. Over the industrial temperature range and a ±25A current range, it achieves state-of-the-art gain error (±0.25%) with both low-cost PCB and stable metal-alloy shunts.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic InstrumentationMicroelectronic
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