8,588 research outputs found

    A new tissue test for accurate diagnosis of copper deficiency in cereals

    Get PDF
    Copper deficiency in ceereals can now be accurately diagnosed using tissue analysis

    Symptoms and treatment of copper deficiency of wheat

    Get PDF
    Copper deficiency in wheat is still common but may not be easily noticed

    Extreme alpha-clustering in the 18O nucleus

    Get PDF
    The structure of the 18O nucleus at excitation energies above the alpha decay threshold was studied using 14C+alpha resonance elastic scattering. A number of states with large alpha reduced widths have been observed, indicating that the alpha-cluster degree of freedom plays an important role in this N not equal Z nucleus. However, the alpha-cluster structure of this nucleus is very different from the relatively simple pattern of strong alpha-cluster quasi-rotational bands in the neighboring 16O and 20Ne nuclei. A 0+ state with an alpha reduced width exceeding the single particle limit was identified at an excitation energy of 9.9+/-0.3 MeV. We discuss evidence that states of this kind are common in light nuclei and give possible explanations of this feature.Comment: 4 pages, 2 figures, 1 table. Resubmission with minor changes for clarity, including removal of one figur

    Quantum Monte Carlo calculations of six-quark states

    Full text link
    The variational Monte Carlo method is used to find the ground state of six quarks confined to a cavity of diameter R_c, interacting via an assumed non-relativistic constituent quark model (CQM) Hamiltonian. We use a flux-tube model augmented with one-gluon and one-pion exchange interactions, which has been successful in describing single hadron spectra. The variational wave function is written as a product of three-quark nucleon states with correlations between quarks in different nucleons. We study the role of quark exchange effects by allowing flux-tube configuration mixing. An accurate six-body variational wave function is obtained. It has only ~13% rms fluctuation in the total energy and yields a standard deviation of ~<.1%; small enough to be useful in discerning nuclear interaction effects from the large rest mass of the two nucleons. Results are presented for three values of the cavity diameter, R_c=2, 4, and 6 fm. They indicate that the flux-tube model Hamiltonian with gluon and pion exchange requires revisions in order to obtain agreement with the energies estimated from realistic two-nucleon interactions. We calculate the two-quark probability distribution functions and show how they may be used to study and adjust the model Hamiltonian.Comment: 49 pages, 13 figures, submitted to Phys. Rev.

    Observables in the Decays of B to Two Vector Mesons

    Full text link
    In general there are nine observables in the decay of a B meson to two vector mesons defined in terms of polarization correlations of these mesons. Only six of these can be detected via the subsequent decay angular distributions because of parity conservation in those decays. The remaining three require the measurement of the spin polarization of one of the decay products.Comment: 12 pages, no figur

    Occupational balance: What tips the scales for new students?

    Get PDF
    The open question, ‘What prevents you from reaching occupational balance?’, was posed within a questionnaire aimed at exploring the meanings of occupation, health and wellbeing with a cohort of first-year occupational therapy students during their initial few weeks at university. Their written responses to the question about occupational balance were analysed and are discussed in this paper. Not surprisingly, occupational balance appeared to be achieved by only a few and more by chance than design. People, time and money factors were identified as the main impediments to achieving occupational balance, with psychological and emotional pressures being at the forefront. Interestingly, despite these barriers, the overall educational benefit of considering the occupational balance question in this way raised the students’ awareness of its relationship to health and wellbeing. This increased awareness might have longer-term health benefits, both personally and professionally, which would be worthy of further research

    An optical-IR jet in 3C133

    Get PDF
    We report the discovery of a new optical-IR synchrotron jet in the radio galaxy 3C133 from our HST/NICMOS snapshot survey. The jet and eastern hotspot are well resolved, and visible at both optical and IR wavelengths. The IR jet follows the morphology of the inner part of the radio jet, with three distinct knots identified with features in the radio. The radio-IR SED's of the knots are examined, along with those of two more distant hotspots at the eastern extreme of the radio feature. The detected emission appears to be synchrotron, with peaks in the NIR for all except one case, which exhibits a power-law spectrum throughout.Comment: ApJ accepted. 14 pages, 6 figure

    Interweaving in hybrid methodologies

    Get PDF
    The paper will consider instances of the interweaving of theory and practice within drawing research, in order to suggest potential approaches to the development of hybrid methodologies in fine art practice-led research. The paper is written from the position of two current supervisors and creative research collaborators: Deborah Harty and Phil Sawdon (aka humhyphenhum from 2007), who historically were supervisee/supervisor. The paper will make reference to Harty's experience as a Ph.D. researcher undertaking practice-led research within a fine art context (completed 2010) and supervised by Sawdon. A discussion of Harty's hybrid methodology: action theoria, will provide an instance of the interweaving of theory and practice. Action theoria incorporates the cyclical and iterative process of action research – intention; action; review – with a process of theoria – the dialogue of both practice and theory's relationship to a given subject matter. Following this, the paper will discuss the interweaving of action theoria into humhyphenhum's collaborative research methodology: meaningful play. This interwoven methodology evolved during collaborative practice-led research projects from 2005 to the present. The paper will make reference to several of humhyphenhum's projects as a means to identify the interweaving of theory and practice within collaborative research. As current supervisors (2015), the paper will conclude with a discussion of how reflection on these experiences has informed our position as supervisors. We will consider, for example, how this has impacted on our ability, as individual supervisors, to offer insights into the interweaving of theory and practice, without defaulting to the position of compelling our supervisees to adopt our methodology

    Understanding Search Trees via Statistical Physics

    Full text link
    We study the random m-ary search tree model (where m stands for the number of branches of a search tree), an important problem for data storage in computer science, using a variety of statistical physics techniques that allow us to obtain exact asymptotic results. In particular, we show that the probability distributions of extreme observables associated with a random search tree such as the height and the balanced height of a tree have a traveling front structure. In addition, the variance of the number of nodes needed to store a data string of a given size N is shown to undergo a striking phase transition at a critical value of the branching ratio m_c=26. We identify the mechanism of this phase transition, show that it is generic and occurs in various other problems as well. New results are obtained when each element of the data string is a D-dimensional vector. We show that this problem also has a phase transition at a critical dimension, D_c= \pi/\sin^{-1}(1/\sqrt{8})=8.69363...Comment: 11 pages, 8 .eps figures included. Invited contribution to STATPHYS-22 held at Bangalore (India) in July 2004. To appear in the proceedings of STATPHYS-2

    NN interaction in a Goldstone boson exchange model

    Full text link
    Adiabatic nucleon-nucleon potentials are calculated in a six-quark nonrelativistic chiral constituent quark model where the Hamiltonian contains a linear confinement and a pseudoscalar meson (Goldstone boson) exchange interaction between quarks. Calculations are performed both in a cluster model and a molecular orbital basis, through coupled channels. In both cases the potentials present an important hard core at short distances, explained through the dominance of the [51]_{FS} configuration, but do not exhibit an attractive pocket. We add a scalar meson exchange interaction and show how it can account for some middle-range attraction.Comment: 32 pages with 12 eps figures incorporated, RevTeX. Final version published in PR
    • …
    corecore