A Guide to the Zygotic Embryo Culture of Coconut Palms (Cocos nucifera L.)

Crop Production/Industries,

Properties of the Bose glass phase in irradiated superconductors near the matching field

Structural and transport properties of interacting localized flux lines in the Bose glass phase of irradiated superconductors are studied by means of Monte Carlo simulations near the matching field B_Phi, where the densities of vortices and columnar defects are equal. For a completely random columnar pin distribution in the xy-plane transverse to the magnetic field, our results show that the repulsive vortex interactions destroy the Mott insulator phase which was predicted to occur at B = B_Phi. On the other hand, for ratios of the penetration depth to average defect distance lambda/d <= 1, characteristic remnants of the Mott insulator singularities remain visible in experimentally accessible quantities as the magnetization, the bulk modulus, and the magnetization relaxation, when B is varied near B_Phi. For spatially more regular disorder, e.g., a nearly triangular defect distribution, we find that the Mott insulator phase can survive up to considerably large interaction range \lambda/d, and may thus be observable in experiments.Comment: RevTex, 17 pages, eps files for 12 figures include

Quality of Life in a Mixed Ethnic Population after Myocardial Infarction

Background: Although South Asian people are a significant ethnic group at increased risk of coronary heart disease and high mortality rates and experience greater delays with respect to diagnosis, referral and treatment, comparatively little is known about their quality of life during recovery from a myocardial infarction.Objectives: We sought to determine and compare the impact of ethnicity on quality of life after myocardial infarction (MI) in a mixed ethnic population (South Asian and white people) in the UK.Methods: A 2x2 mixed-group design with repeated measures on the second factor. The independent variables were ethnic group (white/South Asian) and time since MI (2 weeks/3 months). The dependent variables were the subscale scores on the Short-Form 36-item health survey (SF-36) and the Hospital Anxiety and Depression Scale (HADS).Results: At 2 weeks, significant differences were observed between groups on 5 of the 8 SF-36 subscale domain scores, with the white group reporting higher quality of life. Significant improvement in reported quality of life occurred in both groups over time on all domains of the SF-36, except bodily pain. There was a significantly greater improvement in favour of the white group for the role-physical domain. There was no significant difference between groups in terms of anxiety or depression at 2 weeks. Both groups showed a significant reduction in anxiety and depression by 3 months, but the degree of reduction was not significantly different between them. At 3 months, there was no significant difference between groups in terms of anxiety scores, but the South Asian group scored significantly higher on the depression scale.Conclusions: South Asian people have significantly poorer quality of life than white people after MI. While both groups showed improvement over time, South Asian people reported significantly less improvement in physical role function and were more depressed at 3 months. Identifying the factors accounting for such differences is important to develop models of care for delivering the most effective and culturally-sensitive interventions to this group

Information Presentation

The goal of the Information Presentation Directed Research Project (DRP) is to address design questions related to the presentation of information to the crew. The major areas of work, or subtasks, within this DRP are: 1) Displays, 2) Controls, 3) Electronic Procedures and Fault Management, and 4) Human Performance Modeling. This DRP is a collaborative effort between researchers at Johnson Space Center and Ames Research Center

A simple and efficient numerical scheme to integrate non-local potentials

As nuclear wave functions have to obey the Pauli principle, potentials issued from reaction theory or Hartree-Fock formalism using finite-range interactions contain a non-local part. Written in coordinate space representation, the Schrodinger equation becomes integro-differential, which is difficult to solve, contrary to the case of local potentials, where it is an ordinary differential equation. A simple and powerful method has been proposed several years ago, with the trivially equivalent potential method, where non-local potential is replaced by an equivalent local potential, which is state-dependent and has to be determined iteratively. Its main disadvantage, however, is the appearance of divergences in potentials if the wave functions have nodes, which is generally the case. We will show that divergences can be removed by a slight modification of the trivially equivalent potential method, leading to a very simple, stable and precise numerical technique to deal with non-local potentials. Examples will be provided with the calculation of the Hartree-Fock potential and associated wave functions of 16O using the finite-range N3LO realistic interaction.Comment: 8 pages, 2 figures, submitted to Eur. Phys. J.

Source population synthesis and the Galactic diffuse gamma-ray emission

Population synthesis is used to study the contribution from undetected sources to the Galactic ridge emission measured by EGRET. Synthesized source counts are compared with the 3rd EGRET catalogue at low and high latitudes. For pulsar-like populations, 5-10% of the emission >100 MeV comes from sources below the EGRET threshold. A steeper luminosity function can increase this to 20% without violating EGRET source statistics. Less luminous populations can produce much higher values without being detected. Since the unresolved source spectrum is different from the interstellar spectrum, it could provide an explanation of the observed MeV and GeV excesses above the predictions, and we give an explicit example of how this could work.Comment: Astrophysics and Space Science, in press. (Proceedings of Conference 'The multi-messenger approach to high-energy gamma-ray sources', Barcelona, 2006). Minor changes for accepted version, updated reference

Stochastic Variational Search for ΛΛ4^{4}_{\Lambda\Lambda}H

A four-body calculation of the $pn\Lambda\Lambda$ bound state, $^{\ 4}_{\Lambda\Lambda}$H, is performed using the stochastic variational method and phenomenological potentials. The$NN$,$\Lambda N$, and$\Lambda\Lambda$potentials are taken from a recent Letter by Filikhin and Gal, PRL{\bf 89}, 172502 (2002). Although their Faddeev-Yakubovsky calculation found no bound-state solution over a wide range of$\Lambda\Lambda$interaction strengths, the present variational calculation gives a bound-state energy, which is clearly lower than the$_\Lambda^3{H}+\Lambda$threshold, even for a weak$\Lambda\Lambda$interaction strength deduced from a recent experimental$B_{\Lambda\Lambda}(^{6}_{\Lambda\Lambda}{He})$value. The binding energies obtained are close to, and slightly larger than, the values obtained from the three-body$d\Lambda\Lambda$ model in the Letter.Comment: Corrected typos, added addtional calculations regarding a truncated to l=0 interaction model, 4 pages, 3 figure

Relativistic effects and quasipotential equations

We compare the scattering amplitude resulting from the several quasipotential equations for scalar particles. We consider the Blankenbecler-Sugar, Spectator, Thompson, Erkelenz-Holinde and Equal-Time equations, which were solved numerically without decomposition into partial waves. We analyze both negative-energy state components of the propagators and retardation effects. We found that the scattering solutions of the Spectator and the Equal-Time equations are very close to the nonrelativistic solution even at high energies. The overall relativistic effect increases with the energy. The width of the band for the relative uncertainty in the real part of the scattering $T$ matrix, due to different dynamical equations, is largest for backward-scattering angles where it can be as large as 40%.Comment: Accepted for publication in Phys. Rev.

Exploring the performance of the spectrometer prisma in heavy zirconium and xenon mass regions

We present results from two recent runs which illustrate the performance of the PRISMA spectrometer in the proximity of the upper limit of its operational interval, namely 96Zr + 124Sn at Elab = 500 MeV and 136Xe + 208Pb at Elab = 930 MeV. In the latter run, the γ array CLARA also allowed us to identify previously unknown γ transitions in the nuclides 136Cs and 134I