136 research outputs found

    Collisional properties of sympathetically cooled 39^{39}K

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    We report the experimental evidence of the sympathetic cooling of 39^{39}K with 87^{87}Rb down to 1 μ\muK, obtained in a novel tight confining magnetic trap. This allowed us to perform the first direct measurement of the elastic cross section of 39^{39}K below 50 μ\muK. The result obtained for the triplet scattering length, aT=−51(7)a_T = -51(7) Bohr radii, agrees with previous results derived from photoassociation spectra and from Feshbach spectroscopy of 40^{40}K.Comment: 7 pages, 4 figures, submitted to Phys. Rev.

    Intense slow beams of bosonic potassium isotopes

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    We report on an experimental realization of a two-dimensional magneto-optical trap (2D-MOT) that allows the generation of cold atomic beams of 39K and 41K bosonic potassium isotopes. The high measured fluxes up to 1.0x10^11 atoms/s and low atomic velocities around 33 m/s are well suited for a fast and reliable 3D-MOT loading, a basilar feature for new generation experiments on Bose-Einstein condensation of dilute atomic samples. We also present a simple multilevel theoretical model for the calculation of the light-induced force acting on an atom moving in a MOT. The model gives a good agreement between predicted and measured flux and velocity values for our 2D-MOT.Comment: Updated references, 1 figure added, 10 pages, 9 figure

    Double species condensate with tunable interspecies interactions

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    We produce Bose-Einstein condensates of two different species, 87^{87}Rb and 41^{41}K, in an optical dipole trap in proximity of interspecies Feshbach resonances. We discover and characterize two Feshbach resonances, located around 35 and 79 G, by observing the three-body losses and the elastic cross-section. The narrower resonance is exploited to create a double species condensate with tunable interactions. Our system opens the way to the exploration of double species Mott insulators and, more in general, of the quantum phase diagram of the two species Bose-Hubbard model.Comment: 4 pages, 4 figure

    Unstable regimes for a Bose-Einstein condensate in an optical lattice

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    We report on the experimental characterization of energetic and dynamical instability, two mechanisms responsible for the breakdown of Bloch waves in a Bose-Einstein condensate interacting with a 1D optical lattice. A clear separation of these two regimes is obtained performing measurements at different temperatures of the atomic sample. The timescales of the two processes have been determined by measuring the losses induced in the condensate. A simple phenomenological model is introduced for energetic instability while a full comparison is made between the experiment and the 3D Gross-Pitaevskii theory that accounts for dynamical instability

    Observation of dynamical instability for a Bose-Einstein condensate in a moving 1D optical lattice

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    We have experimentally studied the unstable dynamics of a harmonically trapped Bose-Einstein condensate loaded into a 1D moving optical lattice. The lifetime of the condensate in such a potential exhibits a dramatic dependence on the quasimomentum state. This is unambiguously attributed to the onset of dynamical instability, after a comparison with the predictions of the Gross-Pitaevskii theory. Deeply in the unstable region we observe the rapid appearance of complex structures in the atomic density profile, as a consequence of the condensate phase uniformity breakdown

    Individually Tailored Screening of Susceptibility to Sarcopenia Using p53 Codon 72 Polymorphism, Phenotypes, and Conventional Risk Factors

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    Background and Aim. p53 activity plays a role in muscle homeostasis and skeletal muscle differentiation; all pathways that lead to sarcopenia are related to p53 activities. We investigate the allelic frequency of the TP53 codon 72 in exon 4 polymorphism in the Italian female population and the association with appendicular skeletal muscle mass index in normal weight (NW), normal weight obese (NWO), and preobese-obese (Preob-Ob) subjects. Methods. We evaluated anthropometry, body composition, and p53 polymorphism in 140 women distinguished in NW, NWO, and Preob-Ob. Results. ∗Arg/∗Arg genotype increases sarcopenia risk up to 20% (∗Arg/∗Arg genotype OR = 1.20; 95% CI = 0.48–2.9; ∗proallele carriers OR = 0.83; 95% CI = 0.83–2.06). The risk of being sarcopenic for ∗Arg/∗Arg genotype in NWO and Preob-Ob is 31% higher than NW carriers of ∗proallele (RR = 0,31, 95% CI = 0,15–0,66, P = 0,0079). We developed a model able to predict sarcopenia risk based on age, body fat, and p53 polymorphism. Conclusion. Our study evidences that genotyping TP53 polymorphism could be a useful new genetic approach, in association with body composition evaluations, to assess sarcopenia risk

    Atomic fountains and optical clocks at SYRTE: status and perspectives

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    In this article, we report on the work done with the LNE-SYRTE atomic clock ensemble during the last 10 years. We cover progress made in atomic fountains and in their application to timekeeping. We also cover the development of optical lattice clocks based on strontium and on mercury. We report on tests of fundamental physical laws made with these highly accurate atomic clocks. We also report on work relevant to a future possible redefinition of the SI second

    Effects of dark chocolate in a population of Normal Weight Obese women: a pilot study.

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    BACKGROUND: Normal weight obese (NWO) syndrome is defined as an excessive body fat associated with a normal body mass index and characterized by a higher risk for cardiovascular morbidity and mortality. Recent studies have demonstrated that dark chocolate (DC) has beneficial effects in the prevention of cardiovascular diseases (CVD) due to its anti-inflammatory and antioxidant properties. AIM: The aim of the present study was to investigate the effects of DC consumption on lipid profile, inflammatory markers, biochemical parameters, and blood pressure, in NWO women. MATERIALS AND METHODS: 15 women affected by NWO syndrome, aged 20-40 years, were included in the study. After a DC-free washout period, subjects received DC (100 g/die) containing 70% cocoa for 7-days. Body composition by Dual energy-X-ray absorptiometry (DXA) was performed at baseline. Blood pressure, anthropometric measurements, biochemical parameters and plasma levels of some cytokines were measured before and after DC consumption. RESULTS: After DC consumption, we observed a significant increase in the HDL cholesterol level (Delta% = +10.41±13,53; p ≤ 0.05), a significant decrease of total cholesterol/HDL cholesterol ratio (Delta %= -11.45±7.03; p ≤ 0.05), LDL/HDL cholesterol ratio (Delta % = -11.70±8.91; p ≤ 0.05), and interleukin-1 receptor antagonist (IL-1Ra) (Delta % = -32.99±3.84; p ≤ 0.05). In addition, a reduction in abdomen circumference was observed. We also found a positive correlation between changes in atherogenic indices, and IL-1Ra, abdomen reduction. CONCLUSIONS: Our findings suggest that regular consumption of DC could be useful in maintaining a good atherogenic profile, due to the favourable effects on HDL cholesterol, lipoprotein ratios and inflammation markers

    Body composition changes and cardiometabolic benefits of a balanced Italian Mediterranean Diet in obese patients with metabolic syndrome

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    Metabolic syndrome (MS) is a cluster of metabolic alteration associated with a higher risk of cardiovascular disease and overall mortality than the single alterations alone. The Italian Mediterranean Diet (IMD) can exert a positive effect on cardiovascular risk and related morbidity and mortality. The aim was to evaluate the benefits of dietary intervention based on a typical IMD on body composition, cardiometabolic changes and reduction in cardiovascular disease in patients with MS. Eighty White Italian subjects with MS were prescribed a balanced hypocaloric IMD. We investigated dietary habits and impact of the diet on health status, blood biochemical markers, anthropometric measurements and body composition during a 6-month follow-up period. Body composition, fat mass and distribution were assessed by Dual X-ray absorptiometry. Adherence to the IMD led to a decrease in body weight (102.59 ± 16.82 to 92.39 ± 15.94 kg, p < 0.001), body mass index (BMI) (38.57 ± 6.94 to 35.10 ± 6.76, <0.001) and waist circumference (112.23 ± 12.55 vs 92.42 ± 18.17 cm, p < 0.001). A significant loss of total body fat especially in waist region was observed. The MS was resolved in 52 % of the patients. Significant improvements in systolic and diastolic blood pressure and fasting glucose occurred. Low-density lipoprotein cholesterol was reduced from 128.74 ± 33.18 to 108.76 ± 38.61 mg/dl (p < 0.001), triglycerides from 169.81 ± 80.80 to 131.02 ± 63.88 mg/dl (p < 0.001). The present results suggest that a dietary intervention based on a typical IMD effectively promotes weight loss and reduces the growing burden of cardiovascular risk factors that typifies patients with MS

    Production of Sodium Bose--Einstein condensates in an optical dimple trap

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    We report on the realization of a sodium Bose--Einstein condensate (BEC) in a combined red-detuned optical dipole trap, formed by two beams crossing in a horizontal plane and a third, tightly focused dimple trap propagating vertically. We produce a BEC in three main steps: loading of the crossed dipole trap from laser-cooled atoms, an intermediate evaporative cooling stage which results in efficient loading of the auxiliary dimple trap, and a final evaporative cooling stage in the dimple trap. Our protocol is implemented in a compact setup and allows us to reach quantum degeneracy even with relatively modest initial atom numbers and available laser power
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