6,928 research outputs found

    Predicting Broiler Breeder's Behavior Using Electronic Identification

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    Rosana G. Moreira, Editor-in-Chief; Texas A&M UniversityThis is a Technical Paper from International Commission of Agricultural Engineering (CIGR, Commission Internationale du Genie Rural) E-Journal Volume 4 (2002): F. Curto, I. Naas, D. Pereira, D. Salagado, M. Murayama and F. Behrens. Predicting Broiler Breeder's Behavior Using Electronic Identification. Vol. IV. December 2002

    Superallowed 0+ to 0+ nuclear beta decays: A new survey with precision tests of the conserved vector current hypothesis and the standard model

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    A new critical survey is presented of all half-life, decay-energy and branching-ratio measurements related to 20 0+ to 0+ beta decays. Compared with our last review, there are numerous improvements: First, we have added 27 recently published measurements and eliminated 9 references; of particular importance, the new data include a number of high-precision Penning-trap measurements of decay energies. Second, we have used the recently improved isospin symmetry-breaking corrections. Third, our calculation of the statistical rate function now accounts for possible excitation in the daughter atom. Finally, we have re-examined the systematic uncertainty associated with the isospin symmetry-breaking corrections by evaluating the radial-overlap correction using Hartree-Fock radial wave functions and comparing the results with our earlier calculations, which used Saxon-Woods wave functions; the provision for systematic uncertainty has been changed as a consequence. The new corrected Ft values are impressively constant and their average, when combined with the muon liftime, yields the up-down quark-mixing element of the Cabibbo-Kobayashi-Maskawa (CKM) matrix, V_{ud} = 0.97425(22). The unitarity test on the top row of the matrix becomes |V_{ud}|^2 + |V_{us}|^2 + |V_{ub}|^2 = 0.99995(61). Both V_{ud} and the unitarity sum have significantly reduced uncertainties compared with our previous survey, although the new value of V_{ud} is statistically consistent with the old one. From these data we also set limits on the possible existence of scalar interactions, right-hand currents and extra Z bosons. Finally, we discuss the priorities for future theoretical and experimental work with the goal of making the CKM unitarity test even more definitive.Comment: 36 pages, 11 tables, 9 figure

    B-> K photon photon via intermediate eta'

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    We examine our previous conjecture that the eta' intermediate resonance has the dominant role in the long distance contributions to B decay into two photons and a strange final state hadron. We calculate the branching ratio of the exclusive B-> K eta'-> K photon photon decay using the nonspectator mechanism for eta' production in charmless hadronic B decays. It is shown that the obtained branching ratio B^eta'(B-> K\gamma\gamma)~ 8.7 X 10^{-7} is more than twice as large as the eta_c contribution to this decay mode.Comment: 6 pages, latex, no figure

    Comparison between simulation results and DEXA investigation of the bone remodelling after implanting a cementless long stem hip prosthesis

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    Bone remodelling around a femoral prosthesis is one of the main reasons of aseptic loosening of the implant’s stem. The difference in stiffness between the bone tissue and the prosthesis leads to unload the periprosthetic bone and thus to decrease the bone mineral density (BMD), which is known as stress shielding. This paper represents a comparison between measured changes in (BMD) in a periprosthetic Femur with a cementless Bicontact stem by prospective dualenergy X-ray absorptiometry study (DEXA)and calculated changes of the (BMD) using a finite element method (FEM). As a result, it is determined that the total deviation between the two investigations is about 18%.DF

    Observation of Flux Reversal in a Symmetric Optical Thermal Ratchet

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    We demonstrate that a cycle of three holographic optical trapping patterns can implement a thermal ratchet for diffusing colloidal spheres, and that the ratchet-driven transport displays flux reversal as a function of the cycle frequency and the inter-trap separation. Unlike previously described ratchet models, the approach we describe involves three equivalent states, each of which is locally and globally spatially symmetric, with spatiotemporal symmetry being broken by the sequence of states.Comment: 4 pages, 2 figures, submitted for publication in Physical Review Letter

    Implications of Recent Measurements of Hadronic Charmless B Decays

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    Implications of recent CLEO measurements of hadronic charmless B decays are discussed. (i) Employing the Bauer-Stech-Wirbel (BSW) model for form factors as a benchmark, the B→π+π−B\to\pi^+\pi^- data indicate that the form factor F0Bπ(0)F_0^{B\pi}(0) is smaller than that predicted by the BSW model, whereas the data of B→ωπ,K∗ηB\to\omega\pi, K^*\eta imply that the form factors A0Bω(0),A0BK∗(0)A_0^{B\omega}(0), A_0^{BK^*}(0) are greater than the BSW model's values. (ii) The tree-dominated modes B→π+π−,ρ0π±,ωπ±B\to\pi^+\pi^-, \rho^0\pi^\pm, \omega\pi^\pm imply that the effective number of colors N_c(LL) for (V-A)(V-A) operators is preferred to be smaller, while the current limit on B→ϕKB\to\phi K shows that N_c(LR)>3. The data of B→Kηâ€ČB\to K\eta' and K∗ηK^*\eta clearly indicate that Nc(LR)≫Nc(LL)N_c(LR)\gg N_c(LL). (iii) In order to understand the observed suppression of π+π−\pi^+\pi^- and non-suppression of KπK\pi modes, both being governed by the form factor F0BπF_0^{B\pi}, the unitarity angle Îł\gamma is preferred to be greater than 90∘90^\circ. By contrast, the new measurement of B±→ρ0π±B^\pm\to\rho^0\pi^\pm no longer strongly favors cos⁥γ<0\cos\gamma<0. (iv) The observed pattern K^-\pi^+\sim \ov K^0\pi^-\sim {2\over 3}K^-\pi^0 is consistent with the theoretical expectation: The constructive interference between electroweak and QCD penguin diagrams in the K−π0K^-\pi^0 mode explains why {\cal B}(B^-\to K^-\pi^0)>{1\over 2}{\cal B}(\ov B^0\to K^-\pi^+). (v) The observation \nc(LL)<3<\nc(LR) and our preference for \nc(LL)\sim 2 and \nc(LR)\sim 6 are justified by a recent perturbative QCD calculation of hadronic rare B decays in the heavy quark limit.Comment: 21 pages; CLEO measurements of several charmless B decay modes are updated. Discussion of the unitarity angle gamma in the \rho\pi mode is revise

    Chirp mitigation of plasma-accelerated beams using a modulated plasma density

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    Plasma-based accelerators offer the possibility to drive future compact light sources and high-energy physics applications. Achieving good beam quality, especially a small beam energy spread, is still one of the major challenges. For stable transport, the beam is located in the focusing region of the wakefield which covers only the slope of the accelerating field. This, however, imprints a longitudinal energy correlation (chirp) along the bunch. Here, we propose an alternating focusing scheme in the plasma to mitigate the development of this chirp and thus maintain a small energy spread

    Risk of post-pregnancy hypertension in women with a history of hypertensive disorders of pregnancy: nationwide cohort study.

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    Objectives To determine how soon after delivery the risk of post-pregnancy hypertension increases in women with hypertensive disorders of pregnancy and how the risk evolves over time.Design Nationwide register based cohort study.Setting Denmark.Populations 482 972 primiparous women with a first live birth or stillbirth between 1995 and 2012 (cumulative incidence analyses), and 1 025 118 women with at least one live birth or stillbirth between 1978 and 2012 (Cox regression analyses).Main outcome measures 10 year cumulative incidences of post-pregnancy hypertension requiring treatment with prescription drugs, and hazard ratios estimated using Cox regression.Results Of women with a hypertensive disorder of pregnancy in a first pregnancy in their 20s, 14% developed hypertension in the first decade post partum, compared with 4% of women with normotensive first pregnancies in their 20s. The corresponding percentages for women with a first pregnancy in their 40s were 32% and 11%, respectively. In the year after delivery, women with a hypertensive disorder of pregnancy had 12-fold to 25-fold higher rates of hypertension than did women with a normotensive pregnancy. Rates in women with a hypertensive disorder of pregnancy were threefold to 10-fold higher 1-10 years post partum and remained twice as high even 20 or more years later.Conclusions The risk of hypertension associated with hypertensive disorders of pregnancy is high immediately after an affected pregnancy and persists for more than 20 years. Up to one third of women with a hypertensive disorder of pregnancy may develop hypertension within a decade of an affected pregnancy, indicating that cardiovascular disease prevention in these women should include blood pressure monitoring initiated soon after pregnancy

    The physical origins and dominant emission mechanisms of Lyman alpha haloes: Results from the TNG50 simulation in comparison to MUSE observations

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    Extended Lyman alpha emission is now commonly detected around high-redshift galaxies through stacking and even on individual basis. Despite recent observational advances, the physical origin of these Lyman alpha haloes (LAHs), as well as their relationships to galaxies, quasars, circumgalactic gas, and other environmental factors remains unclear. We present results from our new Lyman alpha full radiative transfer code voroiltis which runs directly on the unstructured Voronoi tessellation of cosmological hydrodynamical simulations. We make use of the TNG50 simulation and simulate LAHs from redshift z = 2 to z = 5, focusing on star-forming galaxies with 8.0 &lt; log10 (M∗ M⊙) &lt; 10.5. While TNG50 does not directly follow ionizing radiation, it includes an on-the-fly treatment for active galactic nuclei (AGNs) and ultraviolet background radiation with self-shielding, which are important processes impacting the cooling and ionization of the gas. Based on this model, we present the predictions for the stacked radial surface brightness profiles of Ly α as a function of galaxy mass and redshift. Comparison with data from the MUSE UDF at z &gt; 3 reveals a promising level of agreement. We measure the correlations of LAH size and central brightness with galaxy properties, finding that at the masses of 8.5 ≀ log10 (M∗/M⊙) ≀ 9.5, physical LAH sizes roughly double from z = 2 to z = 5. Finally, we decompose the profiles into contributions from diffuse emission and scattered photons from star-forming regions. In our simulations, we find rescattered photons from star-forming regions to be the major source in observed LAHs. Unexpectedly, we find that the flattening of LAH profiles at large radii becomes dominated by photons originating from other nearby haloes rather than diffuse emission itself

    Heterogeneous Catalysis under pressure - In-situ neutron diffraction under industrial conditions

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    The present work describes the application of a tubular reactor that allows in-situ neutron diffraction on working catalysts at high pressures. The designed reactor enables the application to a sample of industrially-relevant reaction conditions, i.e., in a temperature range up to 330° C and 60 bar pressure, coupled with online gas-analysis. Application of the cell is demonstrated by ammonia synthesis over a commercial catalyst with diffraction data obtained from the high-resolution powder diffractometer, Echidna, at the Australian Nuclear Science and Technology Organisation, ANSTO
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