The Perceptions of Community Gardeners at Jones Valley Urban Farm and the Implications for Dietary Interventions

The purpose of this study was to assess the reasons community gardeners at Jones Valley Urban Farm in Birmingham, Alabama participate in the community garden program, as well as to explore the potential impacts such participation has on the members’ health, community, and diet. Twenty active gardeners participated in four focus groups. Gardeners reported prior experience, cost savings, taste, sustainability issues, and provision of fresh and organic food as reasons for participating. Gardeners also reported issues related to sharing, community development, mental health, personal pride, perceived health benefits, and new - found food variety as impacts of their participation. Finding s from this study will hopefully serve to guide future quantitative research evaluating community gardening as a potentially healthful dietary intervention

A product line organization using an open development method

Opening access to the source code for a product is a business strategy that is increasingly used as the basis for innovative collaborations with stakeholders. The strategy has been successful at producing a large quantity of high-quality software. A tactic in this strategy is to effectively use the efforts of many widely dispersed professionals. The processes, software tools and the communication mechanisms used to facilitate concurrent development by a large number of people are of as much interest as the software being created. In this position paper we present our view of how a software product line organization might operate if it used an open development method (ODM) but is not necessarily producing open source software. We will describe a hypothetical product line (HPL), which is part speculation, part our experience, and partly the experience of others

The first correction to the second adiabatic invariant of charged-particle motion

First correction to second adiabatic invariant of charged particle motion in magnetic fiel

Use of surface testing devices to identify potential risk factors for synthetic equestrian surfaces

Mechanical properties of sports surfaces have previously been shown to be influenced by surface drainage, moisture content and compaction but these factors have not yet been quantified for equestrian surfaces. The aim of the study was to examine the effect of three moisture levels (11.96 ± 1.63%, 17.31 ± 1.14%, 19.08 ± 0.78%) and three rates of compaction (1.647±0.02 g/cm3, 1.748±0.046 g/cm3, 1.766±0.039 g/cm3) on the functional properties of a synthetic equestrian surface constructed over two distinct drainage profiles. The surfaces with a high (19.08%) moisture content and medium density when laid on permavoid™ had the most favourable results when taking into account all of the measured parameters with regards to reducing the risk of injury yet potentially offering sufficient support to the horse for efficient locomotion

The electrostatics of a dusty plasma

The potential distribution in a plasma containing dust grains were derived where the Debye length can be larger or smaller than the average intergrain spacing. Three models were treated for the grain-plasma system, with the assumption that the system of dust and plasma is charge-neutral: a permeable grain model, an impermeable grain model, and a capacitor model that does not require the nearest neighbor approximation of the other two models. A gauge-invariant form of Poisson's equation was used which is linearized about the average potential in the system. The charging currents to a grain are functions of the difference between the grain potential and this average potential. Expressions were obtained for the equilibrium potential of the grain and for the gauge-invariant capacitance between the grain and the plasma. The charge on a grain is determined by the product of this capacitance and the grain-plasma potential difference

Correlated quantum percolation in the lowest Landau level

Our understanding of localization in the integer quantum Hall effect is informed by a combination of semi-classical models and percolation theory. Motivated by the effect of correlations on classical percolation we study numerically electron localization in the lowest Landau level in the presence of a power-law correlated disorder potential. Careful comparisons between classical and quantum dynamics suggest that the extended Harris criterion is applicable in the quantum case. This leads to a prediction of new localization quantum critical points in integer quantum Hall systems with power-law correlated disorder potentials. We demonstrate the stability of these critical points to addition of competing short-range disorder potentials, and discuss possible experimental realizations.Comment: 15 pages, 12 figure

Trajectories of charged particles trapped in Earth's magnetic field

I outline the theory of relativistic charged-particle motion in the magnetosphere in a way suitable for undergraduate courses. I discuss particle and guiding center motion, derive the three adiabatic invariants associated with them, and present particle trajectories in a dipolar field. I provide twelve computational exercises that can be used as classroom assignments or for self-study. Two of the exercises, drift-shell bifurcation and Speiser orbits, are adapted from active magnetospheric research. The Python code provided in the supplement can be used to replicate the trajectories and can be easily extended for different field geometries.Comment: 10 pages, 7 figures. Submitted to American Journal of Physic

Adiabatic Motion of a Quantum Particle in a Two-Dimensional Magnetic Field

The adiabatic motion of a charged, spinning, quantum particle in a two - dimensional magnetic field is studied. A suitable set of operators generalizing the cinematical momenta and the guiding center operators of a particle moving in a homogeneous magnetic field is constructed. This allows us to separate the two degrees of freedom of the system into a {\sl fast} and a {\sl slow} one, in the classical limit, the rapid rotation of the particle around the guiding center and the slow guiding center drift. In terms of these operators the Hamiltonian of the system rewrites as a power series in the magnetic length \lb=\sqrt{\hbar c\over eB} and the fast and slow dynamics separates. The effective guiding center Hamiltonian is obtained to the second order in the adiabatic parameter \lb and reproduces correctly the classical limit.Comment: 17 pages, LaTe