8,698 research outputs found

    ImageJ2: ImageJ for the next generation of scientific image data

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    ImageJ is an image analysis program extensively used in the biological sciences and beyond. Due to its ease of use, recordable macro language, and extensible plug-in architecture, ImageJ enjoys contributions from non-programmers, amateur programmers, and professional developers alike. Enabling such a diversity of contributors has resulted in a large community that spans the biological and physical sciences. However, a rapidly growing user base, diverging plugin suites, and technical limitations have revealed a clear need for a concerted software engineering effort to support emerging imaging paradigms, to ensure the software's ability to handle the requirements of modern science. Due to these new and emerging challenges in scientific imaging, ImageJ is at a critical development crossroads. We present ImageJ2, a total redesign of ImageJ offering a host of new functionality. It separates concerns, fully decoupling the data model from the user interface. It emphasizes integration with external applications to maximize interoperability. Its robust new plugin framework allows everything from image formats, to scripting languages, to visualization to be extended by the community. The redesigned data model supports arbitrarily large, N-dimensional datasets, which are increasingly common in modern image acquisition. Despite the scope of these changes, backwards compatibility is maintained such that this new functionality can be seamlessly integrated with the classic ImageJ interface, allowing users and developers to migrate to these new methods at their own pace. ImageJ2 provides a framework engineered for flexibility, intended to support these requirements as well as accommodate future needs

    Findings From Surveys on Adventism, Politics and Social Issues

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    AHSRA Presentation Proposal Abstract: The relationships between Adventism and the social political world has implications for the mission of the church and its involvement in the social issues of our time. Researches present an analysis of research conducted over several decades which explore the relationship of Adventism, politics and social issues

    Adventist Religion & Public Issues Survey

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    Critical Statistical Charge for Anyonic Superconductivity

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    We examine a criterion for the anyonic superconductivity at zero temperature in Abelian matter-coupled Chern-Simons gauge field theories in three dimensions. By solving the Dyson-Schwinger equations, we obtain a critical value of the statistical charge for the superconducting phase in a massless fermion-Chern-Simons model.Comment: 11 pages; to appear in Phys Rev

    Effect of Wavefunction Renormalisation in N-Flavour Qed3 at Finite Temperature

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    A recent study of dynamical chiral symmetry breaking in N-flavour QED3_3 at finite temperature is extended to include the effect of fermion wavefunction renormalisation in the Schwinger-Dyson equations. The simple ``zero-frequency'' truncation previously used is found to lead to unphysical results, especially as T→0T \to 0. A modified set of equations is proposed, whose solutions behave in a way which is qualitatively similar to the T=0T=0 solutions of Pennington et al. [5-8] who have made extensive studies of the effect of wavefunction renormalisation in this context, and who concluded that there was no critical NcN_c (at T=0) above which chiral symmetry was restored. In contrast, we find that our modified equations predict a critical NcN_c at T≠0T \not= 0, and an N−TN-T phase diagram very similar to the earlier study neglecting wavefunction renormalisation. The reason for the difference is traced to the different infrared behaviour of the vacuum polarisation at T=0T=0 and at T≠0T \not= 0.Comment: 17 pages + 13 figures (available upon request), Oxford preprint OUTP-93-30P, IFUNAM preprint FT94-39, LaTe

    Quenched Narrow-Line Laser Cooling of 40Ca to Near the Photon Recoil Limit

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    We present a cooling method that should be generally applicable to atoms with narrow optical transitions. This technique uses velocity-selective pulses to drive atoms towards a zero-velocity dark state and then quenches the excited state to increase the cooling rate. We demonstrate this technique of quenched narrow-line cooling by reducing the 1-D temperature of a sample of neutral 40Ca atoms. We velocity select and cool with the 1S0(4s2) to 3P1(4s4p) 657 nm intercombination line and quench with the 3P1(4s4p) to 1S0(4s5s) intercombination line at 553 nm, which increases the cooling rate eight-fold. Limited only by available quenching laser power, we have transferred 18 % of the atoms from our initial 2 mK velocity distribution and achieved temperatures as low as 4 microK, corresponding to a vrms of 2.8 cm/s or 2 recoils at 657 nm. This cooling technique, which is closely related to Raman cooling, can be extended to three dimensions.Comment: 5 pages, 4 figures; Submitted to PRA Rapid Communication

    K2-231 b: A sub-Neptune exoplanet transiting a solar twin in Ruprecht 147

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    We identify a sub-Neptune exoplanet (Rp=2.5±0.2R_p = 2.5 \pm 0.2 R⊕_\oplus) transiting a solar twin in the Ruprecht 147 star cluster (3 Gyr, 300 pc, [Fe/H] = +0.1 dex). The ~81 day light curve for EPIC 219800881 (V = 12.71) from K2 Campaign 7 shows six transits with a period of 13.84 days, a depth of ~0.06%, and a duration of ~4 hours. Based on our analysis of high-resolution MIKE spectra, broadband optical and NIR photometry, the cluster parallax and interstellar reddening, and isochrone models from PARSEC, Dartmouth, and MIST, we estimate the following properties for the host star: M⋆=1.01±0.03M_\star = 1.01 \pm 0.03 M⊙_\odot, R⋆=0.95±0.03R_\star= 0.95 \pm 0.03 R⊙_\odot, and Teff=5695±50T_{\rm eff} = 5695 \pm 50 K. This star appears to be single, based on our modeling of the photometry, the low radial velocity variability measured over nearly ten years, and Keck/NIRC2 adaptive optics imaging and aperture-masking interferometry. Applying a probabilistic mass-radius relation, we estimate that the mass of this planet is Mp=7+5−3M_p = 7 +5 -3 M⊕_\oplus, which would cause a RV semi-amplitude of K=2±1K = 2 \pm 1 m s−1^{-1} that may be measurable with existing precise RV facilities. After statistically validating this planet with BLENDER, we now designate it K2-231 b, making it the second sub-stellar object to be discovered in Ruprecht 147 and the first planet; it joins the small but growing ranks of 23 other planets found in open clusters.Comment: 24 pages, 7 figures, light curve included as separate fil

    A Scale-Separated Dynamic Mode Decomposition From Observations of the Ionospheric Electron Density Profile

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    We present a method for modeling a time series of ionospheric electron density profiles using modal decompositions. Our method is based on the Dynamic Mode Decomposition (DMD), which provides a means of determining spatiotemporal modes from measurements alone. DMD-derived models can be easily updated as new data is recorded and do not require any physics to inform the dynamics. However, in the case of ionospheric profiles, we find a wide range of oscillations, including some far above the diurnal frequency. Therefore, we propose nontrivial extensions to DMD using multiresolution analysis (MRA) via wavelet decompositions. We call this method the Scale-Separated Dynamic Mode Decomposition (SSDMD) since the MRA isolates fluctuations at different scales within the time series into separated components. We show that this method provides a stable reconstruction of the mean plasma density and can be used to predict the state of the vertical profile at future time steps. We demonstrate the SSDMD method on data sets covering periods of high and low solar activity.Comment: 26 pages, 16 figure

    Fabrication Infrastructure to Enable Efficient Exploration and Utilization of Space

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    Unlike past one-at-a-time mission approaches, system-of-systems infrastructures will be needed to enable ambitious scenarios for sustainable future space exploration and utilization. Fabrication infrastructure will be needed to support habitat structure development, tools and mechanical part fabrication, as well as repair and replacement of ground support and space mission hardware such as life support items, vehicle components and crew systems. The fabrication infrastructure will need the In Situ Fabrication and Repair (ISFR) element, which is working in conjunction with the In Situ Resources Utilization (ISRU) element, to live off the land. The ISFR Element supports the entire life cycle of Exploration by: reducing downtime due to failed components; decreasing risk to crew by recovering quickly from degraded operation of equipment; improving system functionality with advanced geometry capabilities; and enhancing mission safety by reducing assembly part counts of original designs where possible. This paper addresses the fabrication infrastructures that support efficient, affordable, reliable infrastructures for both space exploration systems and logistics; these infrastructures allow sustained, affordable and highly effective operations on the Moon, Mars and beyond
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