Limit cycles in the presence of convection, a first order analysis

We consider a diffusion model with limit cycle reaction functions. In an unbounded domain, diffusion spreads pattern outwards from the source. Convection adds instability to the reaction-diffusion system. We see the result of the instability in a readiness to create pattern. In the case of strong convection, we consider that the first-order approximation may be valid for some aspects of the solution behaviour. We employ the method of Riemann invariants and rescaling to transform the reduced system into one invariant under parameter change. We carry out numerical experiments to test our analysis. We find that most aspects of the solution do not comply with this, but we find one significant characteristic which is approximately first order. We consider the correspondence of the Partial Differential Equation with the Ordinary Differential Equation along rays from the initiation point in the transformed system. This yields an understanding of the behaviour

Turing pattern outside of the Turing domain

There are two simple solutions to reaction-diffusion systems with limit-cycle reaction kinetics, producing oscillatory behaviour. The reaction parameter $\mu$ gives rise to a ‘space-invariant’ solution, and $\mu$ versus the ratio of the diffusion coefficients gives rise to a ‘time-invariant’ solution. We consider the case where both solution types may be possible. This leads to a refinement of the Turing model of pattern formation. We add convection to the system and investigate its effect. More complex solutions arise that appear to combine the two simple solutions. The convective system sheds light on the underlying behaviour of the diffusive system

Near Field Communications: Features and Considerations

The increased availability of wireless technologies to transfer data and information between mobile devices is changing the service expectations of medical library customers. In response, medical librarians have investigated and implemented a variety of services that utilize the emerging wireless technologies being built into each generation of mobile devices. One such wireless technology now available on many smartphones is Near Field Communication. This column provides an overview of wireless technologies, describes the basic features of the near field communications, and discusses considerations to help guide libraries in developing their mobile strategies.Publisher allows immediate open acces

Rest Site Selection by Radio-tagged Raccoons

Daytime resting sites and behavior of 14 radio-tagged raccoons were studied from April 18 to November 27, 1965, with types and use of the sites, daytime activity and shifts at the sites, and approach movements previous to resting being analyzed. The radio system pinpointed 173 rest sites, 7 4 per cent in swamps, 17 per cent in hollow trees, and 9 per cent in squirrel or bird nests. Use of the rest sites did not correlate with habitat type or size of the home range or with distances which animals traveled during their active nightly period. Behavioral influences in selection of particular rest sites seemed to be the onset of parturition, the type of approach - whether meandering or direct - and proximity of some rest sites to swamp feeding areas. The study suggests that no predictable pattern is likely to be evident if an animal remembers and revisits a large number of rest sites

A versatile electrostatic trap

A four electrode electrostatic trap geometry is demonstrated that can be used to combine a dipole, quadrupole and hexapole field. A cold packet of 15ND3 molecules is confined in both a purely quadrupolar and hexapolar trapping field and additionally, a dipole field is added to a hexapole field to create either a double-well or a donut-shaped trapping field. The profile of the 15ND3 packet in each of these four trapping potentials is measured, and the dependence of the well-separation and barrier height of the double-well and donut potential on the hexapole and dipole term are discussed.Comment: submitted to pra; 7 pages, 9 figure

Reply to Comment on "Reevaluation of the parton distribution of strange quarks in the nucleon"

A Comment on the recently published reevaluation of the polarization-averaged parton distribution of strange quarks in the nucleon using final data on the multiplicities of charged kaons in semi-inclusive deep-inelastic scattering is reviewed. Important features of the comparison of one-dimensional projections of the multidimensional HERMES data are pointed out. A test of the leading-order extraction of xS(x) using the difference between charged-kaon multiplicities is repeated. The results are consistent with leading-order predictions within the uncertainties in the input data, and do not invalidate the earlier extraction of xS(x).Comment: Reply Comment to arXiv:1407.372

Microwave Lens for Polar Molecules

We here report on the implementation of a microwave lens for neutral polar molecules suitable to focus molecules both in low-field-seeking and in high-field-seeking states. By using the TE_11m modes of a 12 cm long cylindrically symmetric microwave resonator, Stark-decelerated ammonia molecules are transversally confined. We investigate the focusing properties of this microwave lens as a function of the molecules' velocity, the detuning of the microwave frequency from the molecular resonance frequency, and the microwave power. Such a microwave lens can be seen as a first important step towards further microwave devices, such as decelerators and traps.Comment: 4 pages, 3 figure