Limits on Non-Linear Electrodynamics

In this paper we set a framework in which experiments whose goal is to test QED predictions can be used in a more general way to test non-linear electrodynamics (NLED) which contains low-energy QED as a special case. We review some of these experiments and we establish limits on the different free parameters by generalizing QED predictions in the framework of NLED. We finally discuss the implications of these limits on bound systems and isolated charged particles for which QED has been widely and successfully tested

Vacuum magnetic linear birefringence using pulsed fields: the BMV experiment

We present the current status of the BMV experiment. Our apparatus is based on an up-to-date resonant optical cavity coupled to a transverse magnetic field. We detail our data acquisition and analysis procedure which takes into account the symmetry properties of the raw data with respect to the orientation of the magnetic field and the sign of the cavity birefringence. The measurement result of the vacuum magnetic linear birefringence k_\mathrm{CM}$presented in this paper was obtained with about 200 magnetic pulses and a maximum field of 6.5\,T, giving a noise floor of about$8 \times 10^{-21}$\,T$^{-2}$at$3\sigma$ confidence level

Inverse Cotton-Mouton effect of the Vacuum and of atomic systems

In this letter we calculate the Inverse Cotton-Mouton Effect (ICME) for the vacuum following the predictions of Quantum ElectroDynamics. We compare the value of this effect for the vacuum with the one expected for atomic systems. We finally show that ICME could be measured for the first time for noble gases using state-of-the-art laser systems and for the quantum vacuum with near-future laser facilities like ELI and HiPER, providing in particular a test of the nonlinear behaviour of quantum vacuum at intensities below the Schwinger limit of 4.5x10^33 W/m^2.Comment: Submitted to EP

No light shining through a wall : new results from a photoregeneration experiment

Recently, axion-like particle search has received renewed interest. In particular, several groups have started ``light shining through a wall'' experiments based on magnetic field and laser both continuous, which is very demanding in terms of detector background. We present here the 2$\sigma$ limits obtained so far with our novel set-up consisting of a pulsed magnetic field and a pulsed laser. In particular, we have found that the axion-like particle two photons inverse coupling constant $M$ is $> 8\times 10^5$ GeV provided that the particle mass $m_\mathrm{a} \sim$ 1 meV. Our results definitively invalidate the axion interpretation of the original PVLAS optical measurements with a confidence level greater than 99.9%.Comment: Version that will appear in Physical Review Letters, Vol. 99, n. 18, (2 Nov 2007

Bouncing forward: families living with a type I diabetic child

Background: Despite the multitude of challenges that families living with a child with diabetes face, they have been found to adapt to such an extent that diabetes is viewed as a manageable condition. This study was concerned with the factors that enable these families to adapt. The internationally acclaimed Resiliency Model of Stress, Adjustment and Adaptation served as the framework to conceptualise the families’ adjustment and adaptation processes.Methods: The study was triangular in nature, with an exploratory, descriptive approach; non-probability purposive and snowball sampling techniques were employed. Sixteen families participated in the research. A biographical questionnaire, which included an open-ended question, to be completed in written format, was used in conjunction with seven structuredquestionnaires to gather relevant data. These seven structured questionnaires were an operationalisation of some of the key concepts and processes of the Resiliency Model. Descriptive statistics were used to describe the biographical information.Quantitative data were analysed by means of correlation analysis, while qualitative data were analysed by means of content analysis.Results: Various resilience factors were highlighted, including family time and routines, communication, hardiness, the acceptance of the diabetes, adherence to a treatment regimen, the obtaining of knowledge and skills, and working together as a family unit in managing the diabetes.Conclusions: Family plays a powerful role both in the treatment of chronic illness and in paediatric practice. This article highlights the central role of family in the management of type I diabetes and provides practitioners with insight into the challenges that families face, as well as the strengths that can be developed to improve their resilience in relation to this chronic illness. The identified variables are valuable, in that they can be used as a map to guide prevention and intervention efforts in helping families live with type I diabetes.Keywords: Type I diabetes; family resilience; the Resiliency Model of Family Stress, Adjustment and Adaptation; chronic illness management; family adaptation; family challeng

Circular and linear magnetic birefringences in xenon at λ=1064\lambda = 1064 nm

The circular and linear magnetic birefringences corresponding to the Faraday and the Cotton-Mouton effects, respectively, have been measured in xenon at $\lambda = 1064$ nm. The experimental setup is based on time dependent magnetic fields and a high finesse Fabry-Perot cavity. Our value of the Faraday effect is the first measurement at this wavelength. It is compared to theoretical predictions. Our uncertainty of a few percent yields an agreement at better than 1$\sigma$ with the computational estimate when relativistic effects are taken into account. Concerning the Cotton-Mouton effect, our measurement, the second ever published at $\lambda = 1064$ nm, agrees at better than $1\sigma$ with theoretical predictions. We also compare our error budget with those established for other experimental published values

Observation of the Inverse Cotton-Mouton Effect

We report the observation of the Inverse Cotton-Mouton Effect (ICME) i.e. a magnetization induced in a medium by non resonant linearly polarized light propagating in the presence of a transverse magnetic field. We present a detailed study of the ICME in a TGG crystal showing the dependence of the measured effect on the light intensity, the optical polarization, and on the external magnetic field. We derive a relation between the Cotton-Mouton and Inverse Cotton-Mouton effects that is roughly in agreement with existing experimental data. Our results open the way to applications of the ICME in optical devices

The BMV project: Search for photon oscillations into massive particles

In this contribution to PSAS08 we report on the research activities developed in our Toulouse group, in the framework of the BMV project, concerning the search for photon oscillations into massive particles, such as axion-like particles in the presence of a strong transverse magnetic field. We recall our main result obtained in collaboration with LULI at \'Ecole Polytechnique (Palaiseau, France). We also present the very preliminary results obtained with the BMV experiment which is set up at LNCMP (Toulouse, France).Comment: Proceedings of PSAS'08, to be published in Can. J. Phy

Integrative Effects of Vine Water Relations and Grape Ripeness Level of Vitis vinifera L. cv. Shiraz/Richter 99. II. Grape Composition and Wine Quality

Regulation of grapevine water status is a common practice to manipulate grape composition and winequality. In this investigation the effect of plant water status (two field water capacity-based irrigation levels,75% and 100%, applied at single and combined vine developmental stages) and ripeness level (harvestingat different soluble solid levels) on grape composition and wine quality of Vitis vinifera L. cv. Shiraz/Richter 99 was determined. Integrative effects of vine water relations and grape ripeness level, specificallyin a Mediterranean high winter rainfall area, have not yet been investigated systematically. Source:sinkmechanisms and dynamics and compositional and physical changes during both green berry and ripeningperiods (and in response to environment changes), seemed critical for the final grape composition and winequality/style. Despite relatively favourable conditions of the experiment terroir, additional water was stillrequired to obtain best grape and wine quality. Skin colour and total phenolic contents were stimulated inparticular by 75% (field water capacity) pea size (PS) irrigation, post-véraison (PV) irrigation and 75% peasize+post-véraison irrigation, until the last harvest stage. Treatments that included post-véraison irrigationwere not negative in terms of ripening parameters. Increasing total soluble solids with ripening were notfollowed in parallel by anthocyanin potential. Anthocyanin extractability increased with ripening. A late,overripe harvest may result in wines that are slightly better coloured, but highly alcoholic and tannic.Furthermore, at high ripeness level, differences between treatments largely diminished. Over-ripenessof grapes may have tempering and even negative effects on expected outcomes of seasonal cultivationefforts to produce unique wines. This would not favour economic viability. Although non-irrigated winesfailed to result in exceptional wine quality at any harvest stage, a better result in overall quality wasobtained in comparison to irrigation treatments applied at all stages. Berry and wine composition resultscorresponded with findings on wine sensorial quality. The 75% PS, PV irrigation, and 75% PS+PVirrigation consistently resulted in good quality wines. At the first harvest stage, 75% PV, 100% PV, 75%PS+V and 75% PS+PV irrigations gave most prominent wines; at the second harvest stage, vines irrigated75% at PS, 75% at PS+PV and 75% at PV delivered most prominent wines; and at the third harveststage, 75% PV, 100% PV, 75% PS and 75% PS+PV resulted in most prominent wines. These treatmentsrepresented different wine styles at each harvest stage. Restricted PS irrigation and PV irrigation, as singleor combined treatments, featured prominently in favouring grape and wine composition and wine sensorialquality. Physical and compositional changes in ripening berries and the impact on wine quality and stylewere further clarified. New perspectives on managing time of harvesting with varying vine water status aregiven. Recommendations on vine water status management strategies required to obtain different grapecomposition and wine style are made