20,488 research outputs found
A 2 h periodic variation in the low-mass X-ray binary Ser X-1
No full textSpectroscopy of the low-mass X-ray binary Ser X-1 using the Gran Telescopio Canarias have revealed a ?2 h periodic variability that is present in the three strongest emission lines. We tentatively interpret this variability as due to orbital motion, making it the first indication of the orbital period of Ser X-1. Together with the fact that the emission lines are remarkably narrow, but still resolved, we show that a main-sequence K dwarf together with a canonical 1.4 M? neutron star gives a good description of the system. In this scenario, the most likely place for the emission lines to arise is the accretion disc, instead of a localized region in the binary (such as the irradiated surface or the stream-impact point), and their narrowness is due instead to the low inclination (?10°) of Ser X-1
Fixed Points of Nonexpansive Maps on Closed, Bounded, Convex Sets in l1
No full textIn 1965, W.A. Kirk proved that all reflexive Banach spaces (X, ∥·∥) with normal structure are such that for all nonempty, closed, bounded, and convex subsets C ⊆ X, every nonexpansive map T:C→C has a fixed point, i.e. (X, ∥·∥) has the fixed point property for nonexpansive mappings (FPP(n.e.)).
In 1979, K. Goebel and T. Kuczumow constructed “very irregular” closed, bounded, convex, non-weak∗-compact subsets K of l1, and showed that such K have the FPP(n.e.). We show that we may perturb the sets of Goebel and Kuczumow to construct a new and larger class of sets that have the FPP(n.e.).
Ultimately, we would like to answer the following: which isomorphic l1-basic sequences (xn)n∈N are such that their closed convex hulls have the FPP(n.e.)? Theorem 2.2.1, Theorem 2.3.15, and Theorem 2.3.18 give new and interesting isomorphic l1-basic sequences in (l1, ∥·∥1) whose closed convex hulls have the FPP(n.e.).
In 2003, W. Kaczor and S. Prus showed that under a certain assumption, the sets constructed by Goebel and Kuczumow have the fixed point property for asymptotically nonexpansive mappings and that this is equivalent to the sets having the fixed point property for mappings of asymptotically nonexpansive type.
In the second part of this thesis, we prove a theorem (Theorem 3.4.1) that provides an estimate for the l1-distance of a point to a simplex. As a corollary, we prove an interesting special case of the theorem of Kaczor and Prus.
We further calculate the best uniform-Lipschitz constant of the right shift R on one of the sets K of Goebel and Kuczumow.
We also consider another closed, bounded, convex, non-weak∗-compact subset G of the positive face of the usual unit sphere S in l1. We show that, in contrast to the sets K above, G fails to have the fixed point property for asymptotically nonexpansive mappings
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Relations between x-ray timing features and spectral parameters of galactic black hole x-ray binaries
No full textWe present a study of correlations between spectral and timing parameters for a sample of black hole X-ray binary candidates. Data are taken from GX
339-4, H 1743-322, and XTE J1650-500, as the Rossi X-ray Timing Explorer
(RXTE) observed complete outbursts of these sources. In our study we investigate outbursts that happened before the end of 2009 to make use of the high-energy coverage of the HEXTE detector and select observations that
show a certain type of quasi-periodic oscillations (type-C QPOs). The spectral parameters are derived using the empirical convolution model simpl to model the Comptonized component of the emission together with a disc blackbody for the emission of the accretion disc. Additional spectral features, namely a reflection component, a high-energy cut-off, and excess emission at 6.4 keV, are taken into account. Our investigations confirm the known positive
correlation between photon index and centroid frequency of the QPOs and reveal an anti-correlation between the fraction of up-scattered photons and the QPO frequency. We show that both correlations behave as expected in the “sombrero”
geometry. Furthermore, we find that during outburst decay the correlation between photon index and QPO frequency follow a general track, independent of individual outbursts
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Enhanced colour encoding of materials discrimination information for multiple view dual-energy x-ray imaging
No full textThis thesis reports an investigation into dual-energy X-ray discrimination techniques. These techniques are designed to provide colour-coded materials discrimination information in a sequence of perspective images exhibiting sequential parallax. The methods developed are combined with a novel 3D imaging technique employing depth from motion or kinetic depth effect (KDE). This technique when applied to X-ray images is termed KDEX imaging and was developed previously by the university team for luggage screening applications at security checkpoints. A primary motivation for this research is that the dual-energy X-ray techniques, which are routinely incorporated into ‘standard’ 2D luggage scanners, provide relatively crude materials discrimination information. In this work it was critical that robust materials discrimination and colour encoding process was implemented as the sequential parallax exhibited by the KDEX imagery may introduce colour changes, due to the different X-ray beam paths associated with each perspective image. Any introduction of ‘colour noise’ into the resultant image sequences could affect the perception of depth and hinder the ongoing assessment of the potential utility of the dual-energy KDEX technique. Two dual-energy discrimination methods have been developed, termed K-II and W-E respectively. Employing the total amount of attenuation measured at each energy level and the weight fraction of layered structures, a combination of the K-II and the W-E techniques enables the computation and extraction of a target objects’ effective atomic number (Zeff) and its surface density (ρS) in the presence of masking layers
Reynolds numbers near the ultimate state of turbulent Rayleigh-Bénard convection
No full textWe report on measurements of the mean-flow Reynolds number ReU and the rms fluctuation Reynolds number ReV in turbulent Rayleigh-Bénard convection as a function of the Rayleigh number Ra for 4 x 1011 < Ra < 2 1014 and Pr ' 0:8. Both can be described by the same power law with an effective exponent = 0:44, in agreement with predictions for ReU but in disagreement with predictions for ReV
The XMM-Newton long look of NGC 1365: uncovering of the obscured X-ray source
No full textWe present an analysis of the extreme obscuration variability observed during an XMM–Newton 5-d continuous monitoring of the active galactic nuclei (AGN) in NGC 1365. The source was in a reflection-dominated state in the first ∼1.5 d, then a strong increase in the 7–10 keV emission was observed in ∼10 h, followed by a symmetric decrease. The spectral analysis of the different states clearly shows that this variation is due to an uncovering of the X-ray source. From this observation, we estimate a size of the X-ray source DS < 1013 cm, a distance of the obscuring clouds R∼ 1016 cm and a density n∼ 1011 cm−3. These values suggest that the X-ray absorption/reflection originates from the broad-line region clouds. This is also supported by the resolved width of the iron narrow Kα emission line, consistent with the width of the broad Hβ line
Logarithmic variance profiles and the corresponding f-1 spectra of temperature fluctuations in turbulent Rayleigh-Bénard convection
No full textWe report experimental results for the temperature variance 2(z) and the corresponding frequency spectra P(f) in turbulent Rayleigh-Bénard convection (RBC) in a cylindrical sample of aspect ratioT= D/L = 1:00 (D = 1:12 m is the diameter and L = 1:12 m the height). The measurements were conducted in the Rayleigh-number range 1011 < Ra < 1:35 1014 and Pr ' 0:8. For Ra = 1:35x1014, 2(z) could be described well by a logarithmic dependence on the vertical position z in a range of z 1 < z < z 2 with z 1 ' 70 and z 2 = 0:1L. Here L=(2Nu) is the thickness of a thin thermal sublayer adjacent to the horizontal plate where the heat flux (denoted by the Nusselt number Nu) is carried mostly by thermal diffusion. In the log layer, we found that the temperature spectra had a significant frequency range over which P(f) f with close to 1. As Ra decreased, increased so that the log layer became thinner. At Ra = 2:05 1011, z 2 < z 1 and therefore there was no range for a log layer. Correspondingly, the temperature spectrum near the horizontal plate did not have the f1 scaling form either
Inclusive decays B->DX and B->D*X
No full textComplete Author List: Gibbons L, Johnson SD, Kwon Y, Roberts S, Thorndike EH, Jessop CP, Lingel K, Marsiske H, Perl ML, Schaffner SF, Ugolini D, Wang R, Zhou X, Coan TE, Fadeyev V, Korolkov I, Maravin Y, Narsky I, Shelkov V, Staeck J, Stroynowski R, Volobouev I, Ye J, Artuso M, Efimov A, Frasconi F, Gao M, Goldberg M, He D, Kopp S, Horwitz N, Moneti GC, Mountain R, Mukhin Y, Schuh S, Skwarnicki T, Stone S, Thulasidas M, Viehhauser G, Xing X, Bartelt J, Csorna SE, Jain V, Marka S, Freyberger A, Godang R, Kinoshita K, Lai IC, Pomianowski P, Schrenk S, Bonvicini G, Cinabro D, Greene R, Perera LP, Barish B, Chadha M, Chan S, Eigen G, Miller JS, OGrady C, Schmidtler M, Urheim J, Weinstein AJ, Wurthwein F, Asner DM, Bliss DW, Brower WS, Masek G, Paar HP, Sharma V, Gronberg J, Kutschke R, Lange DJ, Menary S, Morrison RJ, Nelson HN, Nelson TK, Qiao C, Richman JD, Roberts D, Ryd A, Witherell MS, Balest R, Behrens BH, Cho K, Ford WT, Park H, Rankin P, Roy J, Smith JG, Alexander JP, Bebek C, Berger BE, Berkelman K, Bloom K, Cassel DG, Cho HA, Coffman DM, Crowcroft DS, Dickson M, Drell PS, Ecklund KM, Ehrlich R, Elia R, Foland AD, Gaidarev P, Gittelman B, Gray SW, Hartill DL, Heltsley BK, Kandaswamy J, Katayama N, Kim PC, Kreinick DL, Lee T, Liu Y, Ludwig GS, Masui J, Mevissen J, Mistry NB, Ng CR, Nordberg E, Ogg M, Patterson JR, Peterson D, Riley D, Soffer A, Ward C, Athanas M, Avery P, Jones CD, Lohner M, Prescott C, Yang S, Yelton J, Zheng J, Brandenburg G, Briere RA, Gao YS, Kim DYJ, Wilson R, Yamamoto H, Browder TE, Li F, Li Y, Rodriguez JL, Bergfeld T, Eisenstein BI, Ernst J, Gladding GE, Gollin GD, Hans RM, Johnson E, Karliner I, Marsh MA, Palmer M, Selen M, Thaler JJ, Edwards KW, Bellerive A, Janicek R, MacFarlane DB, McLean KW, Patel PM, Sadoff AJ, Ammar R, Baringer P, Bean A, Besson D, Coppage D, Darling C, Davis R, Hancock N, Kotov S, Kravchenko I, Kwak N, Anderson S, Kubota Y, Lattery M, ONeill JJ, Patton S, Poling R, Riehle T, Savinov V, Smith A, Alam MS, Athar SB, Ling Z, Mahmood AH, Severini H, Timm S, Wappler F, Anastassov A, Blinov S, Duboscq JE, Fisher KD, Fujino D, Fulton R, Gan KK, Hart T, Honscheid K, Kagan H, Kass R, Lee J, Spencer MB, Sung M, Undrus A, Wanke R, Wolf A, Zoeller MM, Nemati B, Richichi SJ, Ross WR, Skubic P, Wood M, Bishai M, Fast J, Gerndt E, Hinson JW, Menon N, Miller DH, Shibata EI, Shipsey IPJ, Yurko M</p
Assessing the Relationship of Patient Reported Outcome Measures With Functional Status in Dysferlinopathy: A Rasch Analysis Approach
No full textCopyright \ua9 2022 Mayhew, James, Moore, Sutherland, Jacobs, Feng, Lowes, Alfano, Muni Lofra, Rufibach, Rose, Duong, Bello, Pedrosa-Hern\ue1ndez, Holsten, Sakamoto, Canal, S\ue1nchez-Aguilera Pr\ue1xedes, Thiele, Siener, Vandevelde, DeWolf, Maron, Gordish-Dressman, Hilsden, Guglieri, Hogrel, Blamire, Carlier, Spuler, Day, Jones, Bharucha-Goebel, Salort-Campana, Pestronk, Walter, Paradas, Stojkovic, Mori-Yoshimura, Bravver, D\uedaz-Manera, Pegoraro, Mendell and Straub.Dysferlinopathy is a muscular dystrophy with a highly variable functional disease progression in which the relationship of function to some patient reported outcome measures (PROMs) has not been previously reported. This analysis aims to identify the suitability of PROMs and their association with motor performance.Two-hundred and four patients with dysferlinopathy were identified in the Jain Foundation\u27s Clinical Outcome Study in Dysferlinopathy from 14 sites in 8 countries. All patients completed the following PROMs: Individualized Neuromuscular Quality of Life Questionnaire (INQoL), International Physical Activity Questionnaire (IPAQ), and activity limitations for patients with upper and/or lower limb impairments (ACTIVLIMs). In addition, nonambulant patients completed the Egen Klassifikation Scale (EK). Assessments were conducted annually at baseline, years 1, 2, 3, and 4. Data were also collected on the North Star Assessment for Limb Girdle Type Muscular Dystrophies (NSAD) and Performance of Upper Limb (PUL) at these time points from year 2. Data were analyzed using descriptive statistics and Rasch analysis was conducted on ACTIVLIM, EK, INQoL. For associations, graphs (NSAD with ACTIVLIM, IPAQ and INQoL and EK with PUL) were generated from generalized estimating equations (GEE). The ACTIVLIM appeared robust psychometrically and was strongly associated with the NSAD total score (Pseudo R2 0.68). The INQoL performed less well and was poorly associated with the NSAD total score (Pseudo R2 0.18). EK scores were strongly associated with PUL (Pseudo R2 0.69). IPAQ was poorly associated with NSAD scores (Pseudo R2 0.09). This study showed that several of the chosen PROMs demonstrated change over time and a good association with functional outcomes. An alternative quality of life measure and method of collecting data on physical activity may need to be selected for assessing dysferlinopathy
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