Diverse characteristics of UK organic direct marketing chains

In the past few years, organic direct sales in the UK have grown rapidly. Direct sales are assumed to have short or distinct marketing chains from farm gate to consumer. This paper begins by outlining some current problems with the widely accepted defi nition of organic direct sales and charts some of their diverse characteristics. It goes on to argue that the mix of organic direct and multi-farm direct sales is so diverse that a greater clarification of terms is necessary in order to progress consumer, policy and research understanding

Drifting instabilities of cavity solitons in vertical cavity surface-emitting lasers with frequency selective feedback

In this paper we study the formation and dynamics of self-propelled cavity solitons (CSs) in a model for vertical cavity surface-emitting lasers (VCSELs) subjected to external frequency selective feedback (FSF), and build their bifurcation diagram for the case where carrier dynamics is eliminated. For low pump currents, we find that they emerge from the modulational instability point of the trivial solution, where traveling waves with a critical wavenumber are formed. For large currents, the branch of self-propelled solitons merges with the branch of resting solitons via a pitchfork bifurcation. We also show that a feedback phase variation of 2\pi can transform a CS (whether resting or moving) into a different one associated to an adjacent longitudinal external cavity mode. Finally, we investigate the influence of the carrier dynamics, relevant for VCSELs. We find and analyze qualitative changes in the stability properties of resting CSs when increasing the carrier relaxation time. In addition to a drifting instability of resting CSs, a new kind of instability appears for certain ranges of carrier lifetime, leading to a swinging motion of the CS center position. Furthermore, for carrier relaxation times typical of VCSELs the system can display multistability of CSs.Comment: 11 pages, 12 figure

Does kinesiology taping of the ankles affect proprioceptive control in professional football (soccer) players?

Abstract Objective To determine whether the bilateral application of kinesiology tape (KT) to professional footballers' ankles can improve their lower limb proprioception. Design A single blind randomised crossover study. Participants were randomly assigned to complete a proprioception test in either a taped or not taped condition first. Following a wash out period, participants were then re-tested in the alternate condition. Setting A UK Championship League Football Club, mid-season. Participants Twenty male professional football players over the age of 18, currently match fit with no injuries. Outcome measure Proprioception was assessed by participants undertaking the moving target program on the balance module attached to a Kin-Com 125AP isokinetic dynamometer. A paired sample two tailed t-test was used to assess whether there was a significant difference between the participants test scores in the not taped and taped conditions. Results The bilateral application of KT to professional footballers' ankles did not bring about a significant change in participants' scores when tested with a fine movement and balance control test. Percentage accuracy score mean difference 4.2 (p = 0.285). Conclusion The results of this study do not support the use of KT when applied to the ankles of healthy footballers as a method of improving proprioception

Coupled-mode theory for photonic band-gap inhibition of spatial instabilities

We study the inhibition of pattern formation in nonlinear optical systems using intracavity photonic crystals. We consider mean-field models for singly and doubly degenerate optical parametric oscillators. Analytical expressions for the new (higher) modulational thresholds and the size of the "band gap" as a function of the system and photonic crystal parameters are obtained via a coupled-mode theory. Then, by means of a nonlinear analysis, we derive amplitude equations for the unstable modes and find the stationary solutions above threshold. The form of the unstable mode is different in the lower and upper parts of the band gap. In each part there is bistability between two spatially shifted patterns. In large systems stable wall defects between the two solutions are formed and we provide analytical expressions for their shape. The analytical results are favorably compared with results obtained from the full system equations. Inhibition of pattern formation can be used to spatially control signal generation in the transverse plane

Frequency selection by soliton excitation in nondegenerate intracavity downconversion

We show that soliton excitation in intracavity downconversion naturally selects a strictly defined frequency difference between the signal and idler fields. In particular, this phenomenon implies that if the signal has smaller losses than the idler then its frequency is pulled away from the cavity resonance and the idler frequency is pulled towards the resonance and {\em vice versa}. The frequency selection is shown to be closely linked with the relative energy balance between the idler and signal fields.Comment: 5 pages, 3 figures. To appear in Phys Rev Let

From one- to two-dimensional solitons in the Ginzburg-Landau model of lasers with frequency selective feedback

We use the cubic complex Ginzburg-Landau equation coupled to a dissipative linear equation as a model of lasers with an external frequency-selective feedback. It is known that the feedback can stabilize the one-dimensional (1D) self-localized mode. We aim to extend the analysis to 2D stripe-shaped and vortex solitons. The radius of the vortices increases linearly with their topological charge, $m$, therefore the flat-stripe soliton may be interpreted as the vortex with $m=\infty$, while vortex solitons can be realized as stripes bent into rings. The results for the vortex solitons are applicable to a broad class of physical systems. There is a qualitative agreement between our results and those recently reported for models with saturable nonlinearity.Comment: Submitted to PR

The Rising Light Curves of Type Ia Supernovae

We present an analysis of the early, rising light curves of 18 Type Ia supernovae (SNe Ia) discovered by the Palomar Transient Factory (PTF) and the La Silla-QUEST variability survey (LSQ). We fit these early data flux using a simple power-law $(f(t) = {\alpha\times t^n})$ to determine the time of first light $({t_0})$, and hence the rise-time $({t_{rise}})$ from first light to peak luminosity, and the exponent of the power-law rise ($n$). We find a mean uncorrected rise time of $18.98 {\pm} 0.54$ days, with individual SN rise-times ranging from $15.98$ to $24.7$ days. The exponent n shows significant departures from the simple 'fireball model' of $n = 2$ (or ${f(t) \propto t^2}$) usually assumed in the literature. With a mean value of $n = 2.44 {\pm} 0.13$, our data also show significant diversity from event to event. This deviation has implications for the distribution of 56Ni throughout the SN ejecta, with a higher index suggesting a lesser degree of 56Ni mixing. The range of n found also confirms that the 56Ni distribution is not standard throughout the population of SNe Ia, in agreement with earlier work measuring such abundances through spectral modelling. We also show that the duration of the very early light curve, before the luminosity has reached half of its maximal value, does not correlate with the light curve shape or stretch used to standardise SNe Ia in cosmological applications. This has implications for the cosmological fitting of SN Ia light curves.Comment: 19 pages, 19 figures, accepted for publication in MNRA

Searches for Ultra-Compact Dwarf Galaxies in Galaxy Groups

We present the results of a search for ultra-compact dwarf galaxies (UCDs) in six different galaxy groups: Dorado, NGC1400, NGC0681, NGC4038, NGC4697 and NGC5084. We searched in the apparent magnitude range 17.5 < b_j < 20.5 (except NGC5084: 19.2 < b_j < 21.0). We found 1 definite plus 2 possible UCD candidates in the Dorado group and 2 possible UCD candidates in the NGC1400 group. No UCDs were found in the other groups. We compared these results with predicted luminosities of UCDs in the groups according to the hypothesis that UCDs are globular clusters formed in galaxies. The theoretical predictions broadly agree with the observational results, but deeper surveys are needed to fully test the predictions.Comment: 8 pages, 2 figures, accepted for publication in MNRA

Which doctors and with what problems contact a specialist service for doctors? A cross sectional investigation

Background: In the United Kingdom, specialist treatment and intervention services for doctors are underdeveloped. The MedNet programme, created in 1997 and funded by the London Deanery, aims to fill this gap by providing a self-referral, face-to-face, psychotherapeutic assessment service for doctors in London and South-East England. MedNet was designed to be a low-threshold service, targeting doctors without formal psychiatric problems. The aim of this study was to delineate the characteristics of doctors utilising the service, to describe their psychological morbidity, and to determine if early intervention is achieved. Methods: A cross-sectional study including all consecutive self-referred doctors (n = 121, 50% male) presenting in 2002–2004 was conducted. Measures included standardised and bespoke questionnaires both self-report and clinician completed. The multi-dimensional evaluation included: demographics, CORE (CORE-OM, CORE-Workplace and CORE-A) an instrument designed to evaluate the psychological difficulties of patients referred to outpatient services, Brief Symptom Inventory to quantify caseness and formal psychiatric illness, and Maslach Burnout Inventory. Results: The most prevalent presenting problems included depression, anxiety, interpersonal, self-esteem and work-related issues. However, only 9% of the cohort were identified as severely distressed psychiatrically using this measure. In approximately 50% of the sample, problems first presented in the preceding year. About 25% were on sick leave at the time of consultation, while 50% took little or no leave in the prior 12 months. A total of 42% were considered to be at some risk of suicide, with more than 25% considered to have a moderate to severe risk. There were no significant gender differences in type of morbidity, severity or days off sick. Conclusion: Doctors displayed high levels of distress as reflected in the significant proportion of those who were at some risk of suicide; however, low rates of severe psychiatric illness were detected. These findings suggest that MedNet clients represent both ends of the spectrum of severity, enabling early clinical engagement for a significant proportion of cases that is of importance both in terms of personal health and protecting patient care, and providing a timely intervention for those who are at risk, a group for whom rapid intervention services are in need and an area that requires further investigation in the UK