Microwave-stimulated Raman adiabatic passage in a Bose-Einstein condensate on an atom chip

We report the achievement of stimulated Raman adiabatic passage (STIRAP) in the microwave frequency range between internal states of a Bose-Einstein condensate (BEC) magnetically trapped in the vicinity of an atom chip. The STIRAP protocol used in this experiment is robust to external perturbations as it is an adiabatic transfer, and power-efficient as it involves only resonant (or quasi-resonant) processes. Taking into account the effect of losses and collisions in a non-linear Bloch equations model, we show that the maximum transfer efficiency is obtained for non-zero values of the one- and two-photon detunings, which is confirmed quantitatively by our experimental measurements

Immunogenicity and safety of 13-valent pneumococcal conjugate vaccine (PCV13) formulated with 2-phenoxyethanol in multidose vials given with routine vaccination in healthy infants: An open-label randomized controlled trial.

BACKGROUND: This open-label randomized controlled trial in infants compared safety, tolerability, and immunogenicity of the 13-valent pneumococcal conjugate vaccine (PCV13) formulated with the preservative 2-phenoxyethanol (2-PE) in a multidose vial (MDV) to the current PCV13 without 2-PE in a single-dose syringe (SDS). METHODS: Gambian infants were randomized 1:1 to receive PCV13 as either MDV or SDS at ages 2, 3, and 4months. Serotype-specific antipneumococcal antibody responses and opsonophagocytic activity ([OPA]; subset) were measured at age 5months. Noninferiority was declared if the lower bound of the 97.5% CI for the difference (MDV-SDS) in proportions of subjects achieving IgG concentrations ≥0.35μg/mL (primary endpoint) was greater than -10%. IgG geometric mean concentrations (GMCs) were noninferior if the lower limit of the two-sided 97.5% CI of the geometric mean ratio (MDV vs SDS) was greater than 0.5. Reactogenicity and other adverse events were collected. RESULTS: 500 participants were randomized and vaccinated; 489 (MDV: n=245; SDS: n=244) completed the trial. Noninferiority of MDV was demonstrated for all serotypes as measured by percentage of subjects achieving antibody responses above ≥0.35μg/mL. IgG GMCs (coprimary endpoint) also demonstrated noninferiority of MDV; OPA results supported these findings. Safety and tolerability were comparable between groups. CONCLUSIONS: PCV13 in MDV was safe and immunogenic when administered according to the routine schedule to infants. MDV was noninferior to SDS for all 13 pneumococcal serotypes. Comparable immunogenicity and safety profiles of PCV13 MDV and SDS suggest PCV13 MDV can help optimize vaccination in resource-limited settings. ClinicalTrials.gov NCT01964716 https://clinicaltrials.gov/ct2/show/NCT01964716

The Association between Midnight Salivary Cortisol and Metabolic Syndrome in Korean Adults

BackgroundThe common characteristics of metabolic syndrome (MetS) and Cushing's syndrome suggest that excess cortisol may be involved in the pathogenesis of MetS. Salivary cortisol measurements are simple and can be surrogates for plasma free cortisol, which is the most biologically active form. We evaluated the association between levels of midnight salivary cortisol and MetS in Korean adults.MethodsA total of 46 subjects, aged 20 to 70 years, who visited the Health Care Center at Konkuk University Hospital from August 2008 to August 2009 were enrolled. We compared the levels of midnight salivary cortisol in subjects with MetS with those in subjects without MetS. We analyzed the associations between midnight salivary cortisol levels and components of MetS.ResultsMidnight salivary cortisol levels were higher in the MetS group (70±42.4 ng/dL, n=12) than that in the group without MetS (48.1±36.8 ng/dL, n=34) (P=0.001). Positive correlations were observed between midnight salivary cortisol levels and waist circumference, fasting blood glucose, and homeostasis model assessment of insulin resistance. The risk for MetS was significantly higher in subjects with midnight salivary cortisol levels ≥100 ng/dL than in those with levels <50 ng/dL (odds ratio, 5.9; 95% confidence interval, 2.35 to 36.4).ConclusionThe results showed a positive correlation between midnight salivary cortisol levels and MetS, suggesting that hypercortisolism may be related to MetS

VALIDACIÓN DE UNA HERRAMIENTA INFORMÁTICA PARA EL MUESTREO DE SUPERFICIES CUBIERTAS DE PASTOS / VALIDATION OF A COMPUTER TOOL FOR THE SAMPLE Of PAST COVER SURFACES

Con el objetivo de validar, en cuanto a precisión y viabilidad, el método de Herramienta Informática para el muestreo de superficies cubiertas de pastos, comparándolo con el Método visual de determinación de área cubierta y el Método de peso, mediante separación y pesaje de la muestra, se realizó un estudio en áreas de la Universidad de Ciego de Ávila Máximo Gómez Báez, ubicada en el Km 9 ½, carretera a Morón, de la provincia de Ciego de Ávila. Para el trabajo de campo se seleccionó al azar un área de composición botánica heterogénea y se identificaron las especies de plantas presentes en la cubierta. Este procedimiento permitió obtener 30 observaciones visuales y 6 fotografías totales. Posteriormente se procesó la información de las imágenes tomadas en el campo, en una base de datos mediante la Herramienta informática. El análisis matemático y estadístico de los valores numéricos colectados de cada método, se procesaron mediante el programa Microsoft Excel y el estadístico SPSS versión 15. Los resultados indican que el método visual emplea menos tiempo para estimar la composición botánica del área al compararlo con la Herramienta Informática, mientras que la Herramienta Informática logra humanizar el trabajo del hombre y resulta más preciso

Investigation of Cortisol Dynamics in Human Sweat Using a Graphene-Based Wireless mHealth System

Prompt and accurate detection of stress is essential to the monitoring and management of mental health and human performance. Considering that current methods such as questionnaires are very subjective, we propose a highly sensitive, selective, miniaturized mHealth device based on laser-enabled flexible graphene sensor to non-invasively monitor the level of stress hormones (e.g., cortisol). We report a strong correlation between sweat and circulating cortisol and demonstrate the prompt determination of sweat cortisol variation in response to acute stress stimuli. Moreover, we demonstrate, for the first time, the diurnal cycle and stress-response profile of sweat cortisol, revealing the potential of dynamic stress monitoring enabled by this mHealth sensing system. We believe that this platform could contribute to fast, reliable, and decentralized healthcare vigilance at the metabolic level, thus providing an accurate snapshot of our physical, mental, and behavioral changes

Étude du phénomène de compression de spin dans un condensat de Bose-Einstein piégé sur microcircuit

In this manuscript, we present an experimental study of spin squeezing in a spinor Bose-Einstein condensate of ⁸⁷Rb, arising from a non-linear interaction originating from collisions between the two internal states |F=1, m_F=-1≻ and |F=2, m_F=1≻ of the 5²S_{1/2} manifold. The atoms are cooled down in a magneto-optical trap and magnetically trapped thanks to our atom-chip which acts as a top wall for our vacuum cell. The chip is also used to emit the radio-frequency field that perform the evaporative cooling leading to Bose-Einstein condensation, and the microwave field used to coherently transfer the atoms from one internal state to another.The atomic ensemble in a coherent superposition is well described by the so-called textit{one-axis-twisting} Hamiltonian that contains a term quadratic in the z-component of the spin vector S_z. the strength of this non-linear interaction, initially very weak, depends on the intra- and inter-state s-wave scattering lengths, and can be greatly enhanced by reducing the wave-function spatial overlap between the two states. We therefore place the system in a configuration (high atom number and cigar-shaped trap) for which the two states experience spontaneous relative spatial separation and recombination phases. The impact of this spatial dynamics on the mean field interaction and coherence of the system is experimentally analyzed through the study of the contrast and central frequency of a Ramsey interferometer.Theoretically, when the two states are separated, the spin noise distribution evolves from a uniform circular distribution defined by the quantum projection noise, to an elliptic one whose small axis is smaller than the standard quantum limit, under the action of the S²_z interaction. This is verified experimentally by performing the tomography of the atomic state, when the two internal modes recombine. A squeezing parameter ξ² = -1.3 ± 0.4 dB is reached for 5000 atoms and a 90% contrast. The study of the different instability sources highlights the atomic-density-dependent losses as the main limitation for both the noise reduction and the contrast of the interferometer.This work has been initiated in the context of quantum metrology and represents a step towards the production of spin squeezed states enabling the realization of atom interferometers working below the standard quantum limit. It also addresses the fundamental question of coherence of spinor Bose-Einstein condensates undergoing many elastic and inelastic collisions.Dans ce manuscrit, nous présentons une étude expérimentale du phénomène de compression de spin dans un condensat de Bose-Einstein de ⁸⁷Rb, résultant d'une interaction non-linéaire provenant de collisions entre les deux états internes |F=1, m_F=-1 ≻ et |F=2, m_F=1 ≻ de l'état fondamental 5²S_{1/2}. Les atomes sont refroidis dans un piège magnéto-optique, puis piégés magnétiquement à l'aide de notre puce à atomes jouant le rôle de parois supérieure pour notre enceinte à vide. La puce est aussi utilisée pour émettre le champ radiofréquence permettant le refroidissement évaporatif conduisant à la condensation de Bose-Einstein, ainsi que le champ micro-onde qui réalise le transfert cohérent des atomes d'un état interne à un autre.L'ensemble atomique est décrit par le Hamiltonien one-axis-twisting qui contient un terme quadratique en la composante selon l'axe z du vecteur de spin atomique S_z. L'amplitude de cette interaction non-linéaire, initialement très faible, dépend des longueurs de diffusion des états internes considérés, et peut être grandement augmentée en réduisant le recouvrement des fonctions d'onde. C'est pourquoi le système est placé dans une configuration particulière (grand nombre d'atomes et piège anisotrope de type "cigare") pour laquelle les deux états vont alterner des phases de séparation et recombinaison spatiale. L'impact de cette dynamique spatiale sur l'interaction de champ moyen et la cohérence du système est analysé expérimentalement à travers l'étude du contraste et de la fréquence centrale d'un interféromètre de Ramsey.Théoriquement, lorsque les deux états sont séparés, la distribution de spin se transforme d'une distribution circulaire régie par le bruit de projection quantique, en une ellipse dont le petit axe est inférieur à la limite quantique standard, sous l'effet de l'interaction en S²_z. Ceci est vérifié expérimentalement en réalisant la tomographie de l'état atomique au moment où les deux modes internes se recombinent. Un paramètre de compression de spin ξ² = -1.3 ± 0.4 dB est ainsi obtenu pour 5000 atomes et un contraste de 90%. L'étude des différentes sources d'instabilités a permis d'identifier les pertes atomiques comme limitation principale de la compression de spin et du contraste de l'interféromètre.Ce travail s'inscrit dans le contexte de la métrologie quantique et représente un pas vers la production d'états comprimés en spin permettant la réalisation d'interféromètres atomiques fonctionnant sous la limite quantique standard. La question de la cohérence d'un condensat bimodal soumis à de nombreuses collisions élastiques et inélastiques est aussi adressée