2,327 research outputs found

    A New Technique for Determining the Properties of a Narrow ss-channel Resonance at a Muon Collider

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    We explore an alternative to the usual procedure of scanning for determining the properties of a narrow ss-channel resonance. By varying the beam energy resolution while sitting on the resonance peak, the width and branching ratios of the resonance can be determined. The statistical accuracy achieved is superior to that of the usual scan procedure in the case of a light SM-like Higgs boson with \mh>130\gev or for the lightest pseudogoldstone boson of a strong electroweak breaking model if \mpzero>150\gev.Comment: 4 pages, 1 figur

    Effects of Traveling Wave Ion Mobility Separation on Data Independent Acquisition in Proteomics Studies

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    qTOF mass spectrometry and traveling wave ion mobility separation (TWIMS) hybrid instruments (q- TWIMS-TOF) have recently become commercially available. Ion mobility separation allows an additional dimension of precursor separation inside the instrument, without incurring an increase in instrument time. We comprehensively investigated the effects of TWIMS on data-independent acquisition on a Synapt G2 instrument. We observed that if fragmentation is performed post TWIMS, more accurate assignment of fragment ions to precursors is possible in data independent acquisition. This allows up to 60% higher proteome coverage and higher confidence of protein and peptide identifications. Moreover, the majority of peptides and proteins identified upon application of TWIMS span the lower intensity range of the proteome. It has also been demonstrated in several studies that employing IMS results in higher peak capacity of separation and consequently more accurate and precise quantitation of lower intensity precursor ions. We observe that employing TWIMS results in an attenuation of the detected ion current. We postulate that this effect is binary; sensitivity is reduced due to ion scattering during transfer into a high pressure “IMS zone”, sensitivity is reduced due to the saturation of detector digitizer as a result of the IMS concentration effect. This latter effect limits the useful linear range of quantitation, compromising quantitation accuracy of high intensity peptides. We demonstrate that the signal loss from detector saturation and transmission loss can be deconvoluted by investigation of the peptide isotopic envelope. We discuss the origin and extent of signal loss and suggest methods to minimize these effects on q-TWIMS-TOF instrument in the light of different experimental designs and other IMS/MS platforms described previously

    Low-energy theorems of QCD and bulk viscosity at finite temperature and baryon density in a magnetic field

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    The nonperturbative QCD vacuum at finite temperature and a finite baryon density in an external magnetic field is studied. Equations relating nonperturbative condensates to the thermodynamic pressure for T≠0T\neq 0, μq≠0\mu_q \neq 0 and H≠0H\neq 0 are obtained, and low-energy theorems are derived. A bulk viscosity ζ(T,μ,H)\zeta(T, \mu, H) is expressed in terms of basic thermodynamical quantities describing the quark-gluon matter at T≠0T\neq 0, μq≠0\mu_q \neq 0, and H≠0H\neq 0. Various limiting cases are also considered.Comment: 12 pages; v2: title changed, new section about bulk viscosity and new references added; v3: new discussion adde

    Light Quark Masses in Multi-Quark Interactions

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    We suggest and discuss in detail a multi-quark three flavor Lagrangian of the Nambu -- Jona-Lasinio type, which includes a set of effective interactions proportional to the current quark masses. It is shown that within the dynamical chiral symmetry breaking regime, the masses of the pseudo Goldstone bosons and their chiral partners, members of the low lying scalar nonet, are in perfect agreement with current phenomenological expectations. The role of the new interactions is analyzed.Comment: 8 pages, published versio

    Release and adoption of improved sweetpotato varieties in Southeast and South Asia

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    In this study we close the identified gaps in the existing literature and databases by documenting release and adoption of improved sweetpotato varieties in eight major sweetpotato producing countries in Southeast, South, and East Asia. Methodologically, this study adopts a refined expert elicitation (EE) approach applied in previous projects. EE workshops were used as an inexpensive alternative to the collection of national representative adoption data. An average of 12.67 experts working in the sweetpotato value chain participated in a one-day event to elicit perceived adoption rates and to update release databases. In total, 228 experts attended in 18 workshops held during 2014-2016

    Release and adoption of improved potato varieties in Southeast and South Asia

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    In this study, we close the identified gaps in the existing literature and databases by documenting release and adoption of improved potato varieties in seven major potato producing countries in Southeast, South, and East Asia. Methodologically, this study adopts a refined expert elicitation (EE) approach applied in previous projects. EE workshops were used as an inexpensive alternative to the collection of national representative adoption data. An average of 15 experts working in the potato value chain participated in a one-day event to elicit perceived adoption rates and to update release databases. In total, 347 experts attended 23 workshops which were held during 2014-2016

    Chiral perturbation theory in a magnetic background - finite-temperature effects

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    We consider chiral perturbation theory for SU(2) at finite temperature TT in a constant magnetic background BB. We compute the thermal mass of the pions and the pion decay constant to leading order in chiral perturbation theory in the presence of the magnetic field. The magnetic field gives rise to a splitting between Mπ0M_{\pi^0} and Mπ±M_{\pi^{\pm}} as well as between Fπ0F_{\pi^0} and Fπ±F_{\pi^{\pm}}. We also calculate the free energy and the quark condensate to next-to-leading order in chiral perturbation theory. Both the pion decay constants and the quark condensate are decreasing slower as a function of temperature as compared to the case with vanishing magnetic field. The latter result suggests that the critical temperature TcT_c for the chiral transition is larger in the presence of a constant magnetic field. The increase of TcT_c as a function of BB is in agreement with most model calculations but in disagreement with recent lattice calculations.Comment: 24 pages and 9 fig

    Novel atrazine-binding biomimetics inspired to the D1 protein from the photosystem II of Chlamydomonas reinhardtii

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    Biomimetic design represents an emerging field for improving knowledge of natural molecules, as well as to project novel artificial tools with specific functions for biosensing. Effective strategies have been exploited to design artificial bioreceptors, taking inspiration from complex supramolecular assemblies. Among them, size-minimization strategy sounds promising to provide bioreceptors with tuned sensitivity, stability, and selectivity, through the ad hoc manipulation of chemical species at the molecular scale. Herein, a novel biomimetic peptide enabling herbicide binding was designed bioinspired to the D1 protein of the Photosystem II of the green alga Chlamydomonas reinhardtii. The D1 protein portion corresponding to the QB plastoquinone binding niche is capable of interacting with photosynthetic herbicides. A 50-mer peptide in the region of D1 protein from the residue 211 to 280 was designed in silico, and molecular dynamic simulations were performed alone and in complex with atrazine. An equilibrated structure was obtained with a stable pocked for atrazine binding by three H-bonds with SER222, ASN247, and HIS272 residues. Computational data were confirmed by fluorescence spectroscopy and circular dichroism on the peptide obtained by automated synthesis. Atrazine binding at nanomolar concentrations was followed by fluorescence spectroscopy, highlighting peptide suitability for optical sensing of herbicides at safety limits

    Measurement of gamma p --> K+ Lambda and gamma p --> K+ Sigma0 at photon energies up to 2.6 GeV

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    The reactions gamma p --> K+ Lambda and gamma p --> K+ Sigma0 were measured in the energy range from threshold up to a photon energy of 2.6 GeV. The data were taken with the SAPHIR detector at the electron stretcher facility, ELSA. Results on cross sections and hyperon polarizations are presented as a function of kaon production angle and photon energy. The total cross section for Lambda production rises steeply with energy close to threshold, whereas the Sigma0 cross section rises slowly to a maximum at about E_gamma = 1.45 GeV. Cross sections together with their angular decompositions into Legendre polynomials suggest contributions from resonance production for both reactions. In general, the induced polarization of Lambda has negative values in the kaon forward direction and positive values in the backward direction. The magnitude varies with energy. The polarization of Sigma0 follows a similar angular and energy dependence as that of Lambda, but with opposite sign.Comment: 21 pages, 25 figures, submitted to Eur. Phys. J.
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