929 research outputs found

    Structure of hadron resonances with a nearby zero of the amplitude

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    We discuss the relation between the analytic structure of the scattering amplitude and the origin of an eigenstate represented by a pole of the amplitude.If the eigenstate is not dynamically generated by the interaction in the channel of interest, the residue of the pole vanishes in the zero coupling limit. Based on the topological nature of the phase of the scattering amplitude, we show that the pole must encounter with the Castillejo-Dalitz-Dyson (CDD) zero in this limit. It is concluded that the dynamical component of the eigenstate is small if a CDD zero exists near the eigenstate pole. We show that the line shape of the resonance is distorted from the Breit-Wigner form as an observable consequence of the nearby CDD zero. Finally, studying the positions of poles and CDD zeros of the KbarN-piSigma amplitude, we discuss the origin of the eigenstates in the Lambda(1405) region.Comment: 7 pages, 3 figures, v2: published versio

    Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

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    Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente

    Performance of the CMS Cathode Strip Chambers with Cosmic Rays

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    The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47 microns to 243 microns. The efficiencies for local charged track triggers, for hit and for segments reconstruction were measured, and are above 99%. The timing resolution per layer is approximately 5 ns

    Sustainable enzymatic technologies in waste animal fat and protein management.

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    Waste animal fats and proteins (WAFP) are rich in various animal by-products from food industries. On one hand, increasing production of huge amounts of WAFP brings a great challenge to their appropriate disposal, and raises severe risks to environment and life health. On the other hand, the high fat and protein contents in these animal wastes are valuable resources which can be reutilized in an eco-friendly and renewable way. Sustainable enzymatic technologies are promising methods for WAFP management. This review discussed the application of various enzymes in the conversion of WSFP to value-added biodiesel and bioactivate hydrolysates. New biotechnologies to discover novel enzymes with robust properties were proposed as well. This paper also presented the bio-utilization strategy of animal fat and protein wastes as alternative nutrient media for microorganism growth activities to yield important industrial enzymes cost-effectively

    Bioprocessing for elimination antibiotics and hormones from swine wastewater

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    © 2017 Elsevier B.V. Antibiotics and hormones in swine wastewater have become a critical concern worldwide due to the severe threats to human health and the eco-environment. Removal of most detectable antibiotics and hormones, such as sulfonamides (SAs), SMs, tetracyclines (TCs), macrolides, and estrogenic hormones from swine wastewater utilizing various biological processes were summarized and compared. In biological processes, biosorption and biodegradation are the two major removal mechanisms for antibiotics and hormones. The residuals in treated effluents and sludge of conventional activated sludge and anaerobic digestion processes can still pose risks to the surrounding environment, and the anaerobic processes’ removal efficiencies were inferior to those of aerobic processes. In contrast, membrane bioreactors (MBRs), constructed wetlands (CWs) and modified processes performed better because of their higher biodegradation of toxicants. Process modification on activated sludge, anaerobic digestion and conventional MBRs could also enhance the performance (e.g. removing up to 98% SMs, 88.9% TCs, and 99.6% hormones from wastewater). The hybrid process combining MBRs with biological or physical technology also led to better removal efficiency. As such, modified conventional biological processes, advanced biological technologies and MBR hybrid systems are considered as a promising technology for removing toxicants from swine wastewater

    Cell Nucleus-Targeting Zwitterionic Carbon Dots

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    An innovative nucleus-targeting zwitterionic carbon dot (CD) vehicle has been developed for anticancer drug delivery and optical monitoring. The zwitterionic functional groups of the CDs introduced by a simple one-step synthesis using beta-alanine as a passivating and zwitterionic ligand allow cytoplasmic uptake and subsequent nuclear translocation of the CDs. Moreover, multicolor fluorescence improves the accuracy of the CDs as an optical code. The CD-based drug delivery system constructed by non-covalent grafting of doxorubicin, exhibits superior antitumor efficacy owing to enhanced nuclear delivery in vitro and tumor accumulation in vivo, resulting in highly effective tumor growth inhibition. Since the zwitterionic CDs are highly biocompatible and effectively translocated into the nucleus, it provides a compelling solution to a multifunctional nanoparticle for substantially enhanced nuclear uptake of drugs and optical monitoring of translocation.open

    Improved measurement of the reactor antineutrino flux and spectrum at Daya Bay

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    A Search for Dark Higgs Bosons

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    Recent astrophysical and terrestrial experiments have motivated the proposal of a dark sector with GeV-scale gauge boson force carriers and new Higgs bosons. We present a search for a dark Higgs boson using 516 fb-1 of data collected with the BABAR detector. We do not observe a significant signal and we set 90% confidence level upper limits on the product of the Standard Model-dark sector mixing angle and the dark sector coupling constant.Comment: 7 pages, 5 postscript figures, published version with improved plots for b/w printin

    A critical evaluation of the fish early-life stage toxicity test for engineered nanomaterials: experimental modifications and recommendations

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    There are concerns that regulatory toxicity tests are not fit for purpose for engineered nanomaterials (ENMs) or need modifications. The aim of the current study was to evaluate the OECD 210 fish, early-life stage toxicity test for use with TiO2 ENMs, Ag ENMs, and MWCNT. Both TiO2 ENMS (≤160 mg l(-1)) and MWCNT (≤10 mg l(-1)) showed limited acute toxicity, whilst Ag ENMs were acutely toxic to zebrafish, though less so than AgNO3 (6-day LC50 values of 58.6 and 5.0 µg l(-1), respectively). Evidence of delayed hatching, decreased body length and increased muscle width in the tail was seen in fish exposed to Ag ENMs. Oedema (swollen yolk sacs) was also seen in fish from both Ag treatments with, for example, mean yolk sac volumes of 17, 35 and 39 µm(3) for the control, 100 µg l(-1) Ag ENMs and 5 µg l(-1) AgNO3 treatments, respectively. Among the problems with the standard test guidelines was the inability to maintain the test solutions within ±20 % of nominal concentrations. Pronounced settling of the ENMs in some beakers also made it clear the fish were not being exposed to nominal concentrations. To overcome this, the exposure apparatus was modified with the addition of an exposure chamber that ensured mixing without damaging the delicate embryos/larvae. This allowed more homogeneous ENM exposures, signified by improved measured concentrations in the beakers (up to 85.7 and 88.1 % of the nominal concentrations from 10 mg l(-1) TiO2 and 50 µg l(-1) Ag ENM exposures, respectively) and reduced variance between measurements compared to the original method. The recommendations include: that the test is conducted using exposure chambers, the use of quantitative measurements for assessing hatching and morphometrics, and where there is increased sensitivity of larvae over embryos to conduct a shorter, larvae-only toxicity test with the ENMs
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