3,203 research outputs found

    A Gaussian process and image registration based stitching method for high dynamic range measurement of precision surfaces

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    Optical instruments are widely used for precision surface measurement. However, the dynamic range of optical instruments, in terms of measurement area and resolution, is limited by the characteristics of the imaging and the detection systems. If a large area with a high resolution is required, multiple measurements need to be conducted and the resulting datasets needs to be stitched together. Traditional stitching methods use six degrees of freedom for the registration of the overlapped regions, which can result in high computational complexity. Moreover, measurement error increases with increasing measurement data. In this paper, a stitching method, based on a Gaussian process, image registration and edge intensity data fusion, is presented. Firstly, the stitched datasets are modelled by using a Gaussian process so as to determine the mean of each stitched tile. Secondly, the datasets are projected to a base plane. In this way, the three-dimensional datasets are transformed to two-dimensional (2D) images. The images are registered by using an (x, y) translation to simplify the complexity. By using a high precision linear stage that is integral to the measurement instrument, the rotational error becomes insignificant and the cumulative rotational error can be eliminated. The translational error can be compensated by the image registration process. The z direction registration is performed by a least-squares error algorithm and the (x, y, z) translational information is determined. Finally, the overlapped regions of the measurement datasets are fused together by the edge intensity data fusion method. As a result, a large measurement area with a high resolution is obtained. A simulated and an actual measurement with a coherence scanning interferometer have been conducted to verify the proposed method. The stitching result shows that the proposed method is technically feasible for large area surface measurement

    Compact Nuclei in Galaxies at Moderate Redshift:II. Their Nature and Implications for the AGN Luminosity Function

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    This study explores the space density and properties of active galaxies to z=0.8. We have investigated the frequency and nature of unresolved nuclei in galaxies at moderate redshift as indicators of nuclear activity such as Active Galactic Nuclei (AGN) or starbursts. Candidates are selected by fitting imaged galaxies with multi-component models using maximum likelihood estimate techniques to determine the best model fit. We select those galaxies requiring an unresolved point-source component in the galaxy nucleus, in addition to a disk and/or bulge component, to adequately model the galaxy light. We have searched 70 WFPC2 images primarily from the Medium Deep Survey for galaxies containing compact nuclei. In our survey of 1033 galaxies, the fraction containing an unresolved nuclear component greater than 5% of the total galaxy light is 9+/-1% corrected for incompleteness. In this second of two papers in this series, we discuss the nature of the compact nuclei and their hosts. We present the upper limit luminosity function (LF) for low-luminosity AGN (LLAGN) in two redshift bins to z=0.8. Mild number density evolution is detected for nuclei at -18 -16 and this flatness, combined with the increase in number density, is inconsistent with pure luminosity evolution. Based on the amount of density evolution observed for these objects, we find that almost all present-day spiral galaxies could have hosted a LLAGN at some point in their lives. We also comment on the likely contribution of these compact nuclei to the soft X-ray background.Comment: 50 pages, 14 figures, to appear in ApJ, April 199

    Erenumab in chronic migraine: Patient-reported outcomes in a randomized double-blind study.

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    OBJECTIVE: To determine the effect of erenumab, a human monoclonal antibody targeting the calcitonin gene-related peptide receptor, on health-related quality of life (HRQoL), headache impact, and disability in patients with chronic migraine (CM). METHODS: In this double-blind, placebo-controlled study, 667 adults with CM were randomized (3:2:2) to placebo or erenumab (70 or 140 mg monthly). Exploratory endpoints included migraine-specific HRQoL (Migraine-Specific Quality-of-Life Questionnaire [MSQ]), headache impact (Headache Impact Test-6 [HIT-6]), migraine-related disability (Migraine Disability Assessment [MIDAS] test), and pain interference (Patient-Reported Outcomes Measurement Information System [PROMIS] Pain Interference Scale short form 6b). RESULTS: Improvements were observed for all endpoints in both erenumab groups at month 3, with greater changes relative to placebo observed at month 1 for many outcomes. All 3 MSQ domains were improved from baseline with treatment differences for both doses exceeding minimally important differences established for MSQ-role function-restrictive (≥3.2) and MSQ-emotional functioning (≥7.5) and for MSQ-role function-preventive (≥4.5) for erenumab 140 mg. Changes from baseline in HIT-6 scores at month 3 were -5.6 for both doses vs -3.1 for placebo. MIDAS scores at month 3 improved by -19.4 days for 70 mg and -19.8 days for 140 mg vs -7.5 days for placebo. Individual-level minimally important difference was achieved by larger proportions of erenumab-treated participants than placebo for all MSQ domains and HIT-6. Lower proportions of erenumab-treated participants had MIDAS scores of severe (≥21) or very severe (≥41) or PROMIS scores ≥60 at month 3. CONCLUSIONS: Erenumab-treated patients with CM experienced clinically relevant improvements across a broad range of patient-reported outcomes. CLINICALTRIALSGOV IDENTIFIER: NCT02066415. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that for patients with CM, erenumab treatment improves HRQoL, headache impact, and disability

    Low-Mass Baryon-Antibaryon Enhancements in B Decays

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    The nature of low-mass baryon-antibaryon enhancements seen in B decays is explored. Three possibilities include (i) states near threshold as found in a model by Nambu and Jona-Lasinio, (ii) isoscalar states with JPC=0±+J^{PC} = 0^{\pm +} coupled to a pair of gluons, and (iii) low-mass enhancements favored by the fragmentation process. Ways of distinguishing these mechanisms using angular distributions and flavor symmetry are proposed.Comment: 8 pages, LaTeX, no figures, to be submitted to Phys. Rev. D. One reference adde

    Albedos and diameters of three Mars Trojan asteroids

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    We observed the Mars Trojan asteroids (5261) Eureka and (101429) 1998 VF31 and the candidate Mars Trojan 2001 FR127 at 11.2 and 18.1 microns using Michelle on the Gemini North telescope. We derive diameters of 1.28, 0.78, and <0.52 km, respectively, with corresponding geometric visible albedos of 0.39, 0.32, and >0.14. The albedos for Eureka and 1998 VF31 are consistent with the taxonomic classes and compositions (S(I)/angritic and S(VII)/achrondritic, respectively) and implied histories presented in a companion paper by Rivkin et al. Eureka's surface likely has a relatively high thermal inertia, implying a thin regolith that is consistent with predictions and the small size that we derive.Comment: Icarus, in press. See companion paper 0709.1925 by Rivkin et al; two minor typos fixe

    The changing reality of urothelial bladder cancer: should non-squamous variant histology be managed as a distinct clinical entity?

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    Objectives To assess the effect of non-squamous differentiation (non-SQD) variant histology on survival in muscle-invasive bladder urothelial cancer (UC). Patients and Methods A cohort of 411 radical cystectomy (RC) cases performed with curative intent for muscle-invasive primary UC was identified between 2008 and June 2013. Survival analysis was evaluated using Kaplan–Meier methodology comparing non-variant (NV) + SQD histology to non-SQD variant histology (non-SQD variants). Multivariable cox proportional hazards regression assessed all-cause and disease-specific mortality. Results Of the 411 RC cases, 77 (19%) had non-SQD variant histology. The median overall survival (OS) for non-SQD variant histology was 28 months, whereas the NV+SQD group had not reached the median OS at 74 months (log-rank test P < 0.001). After adjusting for sex, age, pathological stage, and any systemic chemotherapy, patients with non-SQD variant histology at RC had a 1.57-times increased adjusted risk of all-cause mortality (P = 0.027) and 1.69-times increased risk of disease-specific mortality (P = 0.030) compared with NV+SQD patients. Conclusions While SQD behaves similarly to NV, non-SQD variant histology portends worse OS and disease-specific survival regardless of neoadjuvant or adjuvant chemotherapy and pathological stage. Non-SQD variants of UC could perhaps be considered a distinct clinical entity in UC with goals for developing new treatment algorithms through novel clinical trials

    Hyaluronan and CD44 antagonize mitogen-dependent cyclin D1 expression in mesenchymal cells

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    High molecular weight (HMW) hyaluronan (HA) is widely distributed in the extracellular matrix, but its biological activities remain incompletely understood. We previously reported that HMW-HA binding to CD44 antagonizes mitogen-induced S-phase entry in vascular smooth muscle cells (SMCs; Cuff, C.A., D. Kothapalli, I. Azonobi, S. Chun, Y. Zhang, R. Belkin, C. Yeh, A. Secreto, R.K. Assoian, D.J. Rader, and E. Puré. 2001. J. Clin. Invest. 108:1031–1040); we now characterize the underlying molecular mechanism and document its relevance in vivo. HMW-HA inhibits the mitogen-dependent induction of cyclin D1 and down-regulation of p27kip1 in vascular SMCs. p27kip1 messenger RNA levels were unaffected by HMW-HA, but the expression of Skp2, the rate-limiting component of the SCF complex that degrades p27kip1, was reduced. Rescue experiments identified cyclin D1 as the primary target of HMW-HA. Similar results were observed in fibroblasts, and these antimitogenic effects were not detected in CD44-null cells. Analysis of arteries from wild-type and CD44-null mice showed that the effects of HMW-HA/CD44 on cyclin D1 and Skp2 gene expression are detected in vivo and are associated with altered SMC proliferation after vascular injury

    The Caltech CSN project collects sensor data from thousands of personal devices for realtime response to dangerous earthquakes

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    The proliferation of smartphones and other powerful sensor-equipped consumer devices enables a new class of Web application: community sense and response (CSR) systems, distinguished from standard Web applications by their use of community-owned commercial sensor hardware. Just as social networks connect and share human-generated content, CSR systems gather, share, and act on sensory data from users' Internet-enabled devices. Here, we discuss the Caltech Community Seismic Network (CSN) as a prototypical CSR system harnessing accelerometers in smartphones and consumer electronics, including the systems and algorithmic challenges of designing, building, and evaluating a scalable network for real-time awareness of dangerous earthquakes

    Does Squamous Differentiation Portend Worse Outcomes in Urothelial Bladder Cancer?

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    Introduction Interest on the impact of variant histology in bladder cancer prognosis is increasing. Although squamous differentiation is the most well characterized, only recently have less common variants gained increased recognition. We assessed whether squamous differentiation conferred a worse prognosis than nonvariant urothelial bladder cancer in a contemporary cohort of patients treated with radical cystectomy given the increased awareness of other less common variants. Methods We identified patients with squamous differentiation or nonvariant histology on transurethral resection of bladder tumor and/or cystectomy pathology during a 10-year period. Disease specific and overall survival were evaluated using Kaplan-Meier methodology. Cox regression was used to assess variables associated with mortality. Results Between 2003 and 2013, 934 patients underwent cystectomy for urothelial bladder cancer. Overall 617 nonvariant and 118 squamous differentiation cases were identified, and the remainder was nonsquamous differentiation variant histology. Overall 75% of patients with squamous differentiation had muscle invasive disease at diagnosis compared with 59% of those with nonvariant histology (p=0.002). Nonorgan confined disease at cystectomy was more common in patients with squamous differentiation (57% vs 44%, p=0.009). Among cases on neoadjuvant chemotherapy 20% (9 of 45) of nonvariant and 13% (1 of 8) of squamous differentiation were pT0N0 (p=0.527). Median followup was 52 months. Adjusted for demographics, pathological stage and chemotherapy, squamous differentiation was not associated with an increased risk of disease specific (HR 1.35, 95% CI 0.90–2.04, p=0.150) or all cause mortality (HR 0.90, 95% CI 0.60–1.25, p=0.515). Conclusions In a contemporary cohort of urothelial bladder cancer with recognition and characterization of less commonly described variants, squamous differentiation is not associated with a worse disease specific and all cause mortality when compared to a pure nonvariant cohort
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