135 research outputs found

    A New Species of the Genus Sinomicrurus Slowinski, Boundy and Lawson, 2001 (Squamata: Elapidae) from Hainan Province, China

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    A new species of the coral snake genus Sinomicrurus is described based on four specimens from southern Hainan Island (three specimens from Tianchi, Jianfengling National Nature Reserve, one specimen from Diaoluoshan National Nature Reserve), Hainan Province, China. Morphologically, the new species is rather similar to Sinomicrurus kelloggi. However, it is distinct from S. kelloggi by the pattern on the head, the head length, head length/width, the number of infralabial scales, number of bands on dorsal body, and number of blotches on the belly

    Potential of Core-Collapse Supernova Neutrino Detection at JUNO

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    JUNO is an underground neutrino observatory under construction in Jiangmen, China. It uses 20kton liquid scintillator as target, which enables it to detect supernova burst neutrinos of a large statistics for the next galactic core-collapse supernova (CCSN) and also pre-supernova neutrinos from the nearby CCSN progenitors. All flavors of supernova burst neutrinos can be detected by JUNO via several interaction channels, including inverse beta decay, elastic scattering on electron and proton, interactions on C12 nuclei, etc. This retains the possibility for JUNO to reconstruct the energy spectra of supernova burst neutrinos of all flavors. The real time monitoring systems based on FPGA and DAQ are under development in JUNO, which allow prompt alert and trigger-less data acquisition of CCSN events. The alert performances of both monitoring systems have been thoroughly studied using simulations. Moreover, once a CCSN is tagged, the system can give fast characterizations, such as directionality and light curve

    Detection of the Diffuse Supernova Neutrino Background with JUNO

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    As an underground multi-purpose neutrino detector with 20 kton liquid scintillator, Jiangmen Underground Neutrino Observatory (JUNO) is competitive with and complementary to the water-Cherenkov detectors on the search for the diffuse supernova neutrino background (DSNB). Typical supernova models predict 2-4 events per year within the optimal observation window in the JUNO detector. The dominant background is from the neutral-current (NC) interaction of atmospheric neutrinos with 12C nuclei, which surpasses the DSNB by more than one order of magnitude. We evaluated the systematic uncertainty of NC background from the spread of a variety of data-driven models and further developed a method to determine NC background within 15\% with {\it{in}} {\it{situ}} measurements after ten years of running. Besides, the NC-like backgrounds can be effectively suppressed by the intrinsic pulse-shape discrimination (PSD) capabilities of liquid scintillators. In this talk, I will present in detail the improvements on NC background uncertainty evaluation, PSD discriminator development, and finally, the potential of DSNB sensitivity in JUNO

    Robust estimation of bacterial cell count from optical density

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    Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

    A New Microporous Lanthanide Metal–Organic Framework with a Wide Range of pH Linear Response

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    Lanthanide metal–organic frameworks (Ln-MOFs) have attracted extensive attention because of their structural adjustability and wide optical function applications. However, MOFs with a wide linear pH response and stable framework structures in acidic or alkaline solutions are rare to date. Here, we used 4,4′,4″-s-triazine-2,4,6-triyltribenzoate (H3TATB) as an organic ligand, coordinated with lanthanide ions (Eu3+/Tb3+), and synthesized a new metal–organic framework material. The material has a porous three-dimensional square framework structure and emits bright red or green fluorescence under 365 nm UV light. The carboxyl group of the ligand is prone to protonation in an acidic environment, and negatively charged OH− and ligand (TATB3−) have a competitive effect in an alkaline environment, which could affect the coordination ability of ligand. The luminescence degree of the framework decreases with the increase in the degree of acid and base. In particular, such fluorescence changes have a wide linear response (pH = 0–14), which can be used as a potential fluorescence sensing material for pH detection

    Synthesizing Efficient Dynamic Programming Algorithms

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    Dynamic programming is an important optimization technique, but designing efficient dynamic programming algorithms can be difficult even for professional programmers. Motivated by this point, we propose a synthesizer namely MetHyl, which automatically synthesizes efficient dynamic programming algorithms from a possibly inefficient program in the form of relational hylomorphism. MetHyl consists of a transformation system and efficient synthesis algorithms, where the former transforms a hylomorphism to an efficient dynamic programming algorithm via four synthesis tasks, and the latter solves these tasks efficiently. We evaluate MetHyl on 37 tasks related to 16 optimization problems collected from Introduction to Algorithm. The results show that MetHyl achieves exponential speed-ups on 97.3% tasks and the time complexity of the standard solutions on 70.3% tasks with an average time cost of less than one minute

    Microstructure evolution, mechanical response and strengthening models for TA15 titanium alloy during thermal processes: A brief review

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    TA15 titanium alloy is widely used in aerospace industry in terms of its high specific strength, good thermal stability, and excellent corrosion resistance. To further improve its mechanical properties, thermal deformation combined with heat treatment is always used, during which the microstructure evolution and mechanical response are absolutely complex leading to the difficulty in control of final mechanical properties. Therefore, in-depth research on the relationship between microstructure and mechanical response of TA15 titanium alloy during these processes is of great significance. At present, less relevant review has been reported. In this article, the effects of process parameters such as heating temperature, strain rate, deformation amount, deformation mode, deformation path, cooling method and soaking time on the microstructure and mechanical properties of TA15 alloy, namely tensile performance and damage tolerance properties have been discussed. In addition, some strengthening models suitable for TA15 titanium alloy have been analyzed. In conclusion, different microstructure morphologies formed in various processing processes will display diverse mechanical performances in which the direct relationship between the yield strength and microstructure morphology can be established through distinct calculation models but with some limitations. So, in future works, microstructure and mechanical properties should be optimized further through adjusting processing parameters. Moreover, strengthening models remains to be modified by adopting more accurate statistical methods and considering more factors. Finally, establishing the relationship between damage tolerance properties such as fracture toughness, creep performance and LCF property and microstructure features should be considered more for TA15 alloy
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