Understanding the production of dual BEC with sympathetic cooling

We show, both experimentally and theoretically, that sympathetic cooling of $^{87}$Rb atoms in the $|F=2,m_F=2>$ state by evaporatively cooled atoms in the $|F=1,m_F=-1>$ state can be precisely controlled to produce dual or single condensate in either state. We also study the thermalization rate between two species. Our model renders a quantitative account of the observed role of the overlap between the two clouds and points out that sympathetic cooling becomes inefficient when the masses are very different. Our calculation also yields an analytical expression of the thermalization rate for a single species.Comment: 3 figure

Intercomparison of oceanic and atmospheric forced and coupled mesoscale simulations <br>Part I: Surface fluxes

International audienceA mesoscale non-hydrostatic atmospheric model has been coupled with a mesoscale oceanic model. The case study is a four-day simulation of a strong storm event observed during the SEMAPHORE experiment over a 500 × 500 km2 domain. This domain encompasses a thermohaline front associated with the Azores current. In order to analyze the effect of mesoscale coupling, three simulations are compared: the first one with the atmospheric model forced by realistic sea surface temperature analyses; the second one with the ocean model forced by atmospheric fields, derived from weather forecast re-analyses; the third one with the models being coupled. For these three simulations the surface fluxes were computed with the same bulk parametrization. All three simulations succeed well in representing the main oceanic or atmospheric features observed during the storm. Comparison of surface fields with in situ observations reveals that the winds of the fine mesh atmospheric model are more realistic than those of the weather forecast re-analyses. The low-level winds simulated with the atmospheric model in the forced and coupled simulations are appreciably stronger than the re-analyzed winds. They also generate stronger fluxes. The coupled simulation has the strongest surface heat fluxes: the difference in the net heat budget with the oceanic forced simulation reaches on average 50 Wm-2 over the simulation period. Sea surface-temperature cooling is too weak in both simulations, but is improved in the coupled run and matches better the cooling observed with drifters. The spatial distributions of sea surface-temperature cooling and surface fluxes are strongly inhomogeneous over the simulation domain. The amplitude of the flux variation is maximum in the coupled run. Moreover the weak correlation between the cooling and heat flux patterns indicates that the surface fluxes are not responsible for the whole cooling and suggests that the response of the ocean mixed layer to the atmosphere is highly non-local and enhanced in the coupled simulation

Theoretical mass sensitivity of Love wave and layer guided acoustic plate mode sensors

A model for the mass sensitivity of Love wave and layer guided shear horizontal acoustic plate mode (SH–APM) sensors is developed by considering the propagation of shear horizontally polarized acoustic waves in a three layer system. A dispersion equation is derived for this three layer system and this is shown to contain the dispersion equation for the two layer system of the substrate and the guiding layer plus a term involving the third layer, which is regarded as a perturbing mass layer. This equation is valid for an arbitrary thickness perturbing mass layer. The perturbation, Δν, of the wave speed for the two-layer system by a thin third layer of density, ρp and thickness Δh is shown to be equal to the mass per unit area multiplied by a function dependent only on the properties of the substrate and the guiding layer, and the operating frequency of the sensor. The independence of the function from the properties of the third layer means that the mass sensitivity of the bare, two-layer, sensor operated about any thickness of the guiding layer can be deduced from the slope of the numerically or experimentally determined dispersion curve. Formulas are also derived for a Love wave on an infinite thickness substrate describing the change in mass sensitivity due to a change in frequency. The consequences of the various formulas for mass sensing applications are illustrated using numerical calculations with parameters describing a (rigid) poly(methylmethacrylate) wave-guiding layer on a finite thickness quartz substrate. These calculations demonstrate that a layer-guided SH–APM can have a mass sensitivity comparable to, or higher, than that of Love waves propagating on the same substrate. The increase in mass sensitivity of the layer guided SH–APMs over previously studied SH–APM sensors is of significance, particularly for liquid sensing applications. The relevance of the dispersion curve to experiments using higher frequencies or frequency hopping and to experiments using thick guiding layers is discussed

Sorption-induced Static Bending of Microcantilevers Coated with Viscoelastic Material

Absorption of a chemical analyte into a polymercoating results in an expansion governed by the concentration and type of analyte that has diffused into the bulk of the coating. When the coating is attached to a microcantilever, this expansion results in bending of the device. Assuming that absorption (i.e., diffusion across the surface barrier into the bulk of the coating) is Fickian, with a rate of absorption that is proportional to the difference between the absorbed concentration and the equilibrium concentration, and the coating is elastic, the bending response of the coated device should exhibit a first-order behavior. However, for polymercoatings, complex behaviors exhibiting an overshoot that slowly decays to the steady-state value have been observed. A theoretical model of absorption-induced static bending of a microcantilever coated with a viscoelastic material is presented, starting from the general stress/strain relationship for a viscoelastic material. The model accounts for viscoelasticstress relaxation and possible coating plasticization. Calculated responses show that the model is capable of reproducing the same transient behavior exhibited in the experimental data. The theory presented can also be used for extracting viscoelasticproperties of the coating from the measured bending data

If you don’t take it – it can’t work: the consequences of not being treated or nonadherence to osteoporosis therapy

Osteoporosis is a growing problem worldwide, linked to an increasingly aging population. Despite the availability of a wide variety of treatments for osteoporosis, a significant number of patients are either not being prescribed treatment or discontinue therapy as early as 6 months after initiation. The reasons for a lack of adherence are many but poor adherence increases the risk of fracture and, therefore, the disease burden to the patient and society. Results from large-scale, randomized clinical studies have shown that different osteoporosis treatments are efficacious in reducing the risk of fracture. Studies assessing the effects of discontinuing osteoporosis therapies show that some treatments appear to continue to protect patients from the risk of future fracture even when treatment is stopped. However, these trials involve patients who have been compliant with treatment for between 2 and 5 years, a situation not reflective of real-world clinical practice. In reality, patients who discontinue therapy within the first 6 months may never achieve the optimum protection from fracture regardless of which treatment they have been prescribed. Clinicians need to develop management strategies to enable patients to adhere to their treatment. This will ultimately result in better prevention of fracture and a lower burden of disease to society and patients

Entanglement and squeezing in a two-mode system: theory and experiment

We report on the generation of non separable beams produced via the interaction of a linearly polarized beam with a cloud of cold cesium atoms placed in an optical cavity. We convert the squeezing of the two linear polarization modes into quadrature entanglement and show how to find out the best entanglement generated in a two-mode system using the inseparability criterion for continuous variable [Duan et al., Phys. Rev. Lett. 84, 2722 (2000)]. We verify this method experimentally with a direct measurement of the inseparability using two homodyne detections. We then map this entanglement into a polarization basis and achieve polarization entanglement.Comment: submitted to J. Opt. B for a Special Issue on Foundations of Quantum Optic

EczemaPred: a computational framework for personalised prediction of eczema severity dynamics

Background: Atopic dermatitis (AD) is a chronic inflammatory skin disease leading to substantial quality of life impairment with heterogeneous treatment responses. People with AD would benefit from personalised treatment strategies, whose design requires predicting how AD severity evolves for each individual. Objective: This study aims to develop a computational framework for personalised prediction of AD severity dynamics. Methods: We introduced EczemaPred, a computational framework to predict patient-dependent dynamic evolution of AD severity using Bayesian state-space models that describe latent dynamics of AD severity items and how they are measured. We used EczemaPred to predict the dynamic evolution of validated patient-oriented scoring atopic dermatitis (PO-SCORAD) by combining predictions from the models for the nine severity items of PO-SCORAD (six intensity signs, extent of eczema, and two subjective symptoms). We validated this approach using longitudinal data from two independent studies: a published clinical study in which PO-SCORAD was measured twice weekly for 347 AD patients over 17 weeks, and another one in which PO-SCORAD was recorded daily by 16 AD patients for 12 weeks. Results: EczemaPred achieved good performance for personalised predictions of PO-SCORAD and its severity items daily to weekly. EczemaPred outperformed standard time-series forecasting models such as a mixed effect autoregressive model. The uncertainty in predicting PO-SCORAD was mainly attributed to that in predicting intensity signs (75% of the overall uncertainty). Conclusions: EczemaPred serves as a computational framework to make a personalised prediction of AD severity dynamics relevant to clinical practice. EczemaPred is available as an R package

Elimination du fer et du manganèse d’une eau de surface par les graines de Moringa oleifera

Dans cette étude, les échantillons d’eau de la retenue d’Okpara à Parakou ont été traités par les extraits aqueux des graines de Moringa oleifera en vue de réduire les concentrations de fer et de manganèse qu’ils contenaient. Dans deux échantillons d’eau de la retenue dont les concentrations en fer sont 8,20 mg/L et 21,10 mg/L puis 0,90 mg/L et 1,60 mg/L de manganèse, les taux d’abattement aux doses optimales 64 mg/L et 48 mg/L de Moringa oleifera sont respectivement de 80% et 42% pour le fer et 77% et 45% pour le manganèse. Lorsque Moringa a été utilisé comme adjuvant de coagulation au sulfate d’aluminium, 94% de fer et 90% de manganèse ont été éliminés. Ces résultats montrent que la combinaison de Moringa oleifera avec le sulfate d’aluminium conduit à des taux d’abattement de fer et de manganèse meilleurs que ceux obtenus avec le sulfate d’aluminium ou le Moringa oleifera utilisé chacun comme coagulant primaire ; en outre, cette combinaison a l’avantage de réduire la quantité d’alun nécessaire et par conséquent le coût du traitement de l’eau brute diminue.Mot clés: Moringa oleifera - fer - manganèse adjuvant de coagulation - jar-test

The influence of reading ability on subsequent changes in verbal IQ in the teenage years

Intelligence Quotient (IQ) is regularly used in both education and employment as a measure of cognitive ability. Although an individual's IQ is generally assumed to stay constant across the lifespan, a few studies have suggested that there may be substantial variation at the individual level. Motivated by previous reports that reading quality/quantity has a positive influence on vocabulary acquisition, we hypothesised that reading ability in the early teenage years might contribute to changes in verbal IQ (VIQ) over the next few years. We found that good readers were more likely to experience relative improvements in VIQ over time, with the reverse true for poor readers. These effects were largest when there was a discrepancy between Time 1 reading ability and Time 1 VIQ. In other words, VIQ increases tended to be greatest when reading ability was high relative to VIQ. Additional analyses supported these findings by showing that variance in VIQ change associated with Time 1 behaviour was also associated with independent measurements of brain structure. Our finding that reading in the early teenage years can predict a significant proportion of the variance in subsequent VIQ change has implications for targeted education in both home and school environments