656 research outputs found

    Optimized production of large Bose Einstein Condensates

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    We suggest different simple schemes to efficiently load and evaporate a ''dimple'' crossed dipolar trap. The collisional processes between atoms which are trapped in a reservoir load in a non adiabatic way the dimple. The reservoir trap can be provided either by a dark SPOT Magneto Optical Trap, the (aberrated) laser beam itself or by a quadrupolar or quadratic magnetic trap. Optimal parameters for the dimple are derived from thermodynamical equations and from loading time, including possible inelastic and Majorana losses. We suggest to load at relatively high temperature a tight optical trap. Simple evaporative cooling equations, taking into account gravity, the possible occurrence of hydrodynamical regime, Feshbach resonance processes and three body recombination events are given. To have an efficient evaporation the elastic collisional rate (in s−1^{-1}) is found to be on the order of the trapping frequency and lower than one hundred times the temperature in micro-Kelvin. Bose Einstein condensates with more than 10710^7 atoms should be obtained in much less than one second starting from an usual MOT setup.Comment: 14 page

    Observation of a resonant four-body interaction in cold cesium Rydberg atoms

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    Cold Rydberg atoms subject to long-range dipole-dipole interactions represent a particularly interesting system for exploring few-body interactions and probing the transition from 2-body physics to the many-body regime. In this work we report the direct observation of a resonant 4-body Rydberg interaction. We exploit the occurrence of an accidental quasi-coincidence of a 2-body and a 4-body resonant Stark-tuned Forster process in cesium to observe a resonant energy transfer requiring the simultaneous interaction of at least four neighboring atoms. These results are relevant for the implementation of quantum gates with Rydberg atoms and for further studies of many-body physics.Comment: 5 pages, 5 figure

    Ascaridia galli: a report of erratic migration

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    This paper describes a case of an unusual recovery of adult Ascaridia galli in hen's egg. Several data are available on this occurrence but it appears to be the first case described in Italy. The worm was identified as an adult female, 6.8 cm in length, with three trilobed lips, cervical narrow alae, oesophagus club-shaped without posterior bulb, vulva near the middle of body, with gravid uteri containing a large number of eggs. The presence of Ascaridia galli in hen's eggs cannot be considered as hazard for public health but may be cause of a potential consumer complaint. Moreover it is a sign of presence of ascaridiosis, parasitosis that still produces economic losses in modern poultry production system

    The Severe Heart Failure Questionnaire: Italian translation and linguistic validation

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    Introduction. The quality of life (QoL) is an important outcome indicator for heart failure management. As the use of a validate questionnaire in a different cultural context can affect data interpretation our main objective is the Italian translation and linguistic validation of the Severe Heart Failure Questionnaire (SHF) and its comparison with the MLHF (Minnesota Living with Heart Failure) Questionnaire. Methods. The SHF and ?The Minnesota Living with Heart Failure Questionnaire? were translated. A consensus involving parallel back-translations was established among a group of cardiologists, psychologists and biostatisticians. SHF and MLHF were both administrated to a sample of 50 patients Results. The patients? median age was 63 years. Ace inhibitors therapy was administered in 88% of cases and betablockers in 56% of cases. Finally the Italian version of SHF correlates well with MLHF for all domains, except life satisfaction SHF domain. Discussion: The Italian version of the SHF correlates well with MLHF for almost all domains and it represents a valid alterna- tive for quality of life assessment in heart failure patients

    Enhancement of the formation of ultracold 85^{85}Rb2_2 molecules due to resonant coupling

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    We have studied the effect of resonant electronic state coupling on the formation of ultracold ground-state 85^{85}Rb2_2. Ultracold Rb2_2 molecules are formed by photoassociation (PA) to a coupled pair of 0u+0_u^+ states, 0u+(P1/2)0_u^+(P_{1/2}) and 0u+(P3/2)0_u^+(P_{3/2}), in the region below the 5S+5P1/25S+5P_{1/2} limit. Subsequent radiative decay produces high vibrational levels of the ground state, X1Σg+X ^1\Sigma_g^+. The population distribution of these XX state vibrational levels is monitored by resonance-enhanced two-photon ionization through the 21Σu+2 ^1\Sigma_u^+ state. We find that the populations of vibrational levels v′′v''=112−-116 are far larger than can be accounted for by the Franck-Condon factors for 0u+(P1/2)→X1Σg+0_u^+(P_{1/2}) \to X ^1\Sigma_g^+ transitions with the 0u+(P1/2)0_u^+(P_{1/2}) state treated as a single channel. Further, the ground-state molecule population exhibits oscillatory behavior as the PA laser is tuned through a succession of 0u+0_u^+ state vibrational levels. Both of these effects are explained by a new calculation of transition amplitudes that includes the resonant character of the spin-orbit coupling of the two 0u+0_u^+ states. The resulting enhancement of more deeply bound ground-state molecule formation will be useful for future experiments on ultracold molecules.Comment: 6 pages, 5 figures; corrected author lis

    Formation of ultracold LiCs molecules

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    We present the first observation of ultracold LiCs molecules. The molecules are formed in a two-species magneto-optical trap and detected by two-photon ionization and time-of-flight mass spectrometry. The production rate coefficient is found to be in the range 10^{-18}\unit{cm^3s^{-1}} to 10^{-16}\unit{cm^3s^{-1}}, at least an order of magnitude smaller than for other heteronuclear diatomic molecules directly formed in a magneto-optical trap.Comment: 8 pages, 2 figure

    The Left Ventricular Dysfunction Questionnaire: Italian translation and validation.

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    Patients affected by heart failure have a compromised quality of life (QOL) and in the last few years "health related quality of life" has become an important outcome indicator for the evaluation of heart failure treatment. Methods: Translation into Italian of the Left Ventricular Dysfunction Questionnaire (LVD-36), a new, 36-item, disease-specific health status instrument for patients with congestive heart failure, and its subsequent validation by administration to 50 consecutive patients in our heart failure outpatient clinic. The Italian LVD-36 was compared to the "The Minnesota Living with Heart Failure Questionnaire" (MLHF). Results: The Italian version of the LVD-36 correlates well with MLHF for ejection fraction (EF), NYHA class I and II, etiology and therapy. Since, however, the LVD-36 has only one domain, it may be able to offer more synthetic information than MLHF about patients' status. Conclusions: The Italian version of the LVD-36 appears to be a reliable instrument for assessing patients' QOL and the degree of limitations imposed on them by the disease. It is short, clear and easy to complete. In patients with heart failure the LVD-36 correlates well with the MLHF and may be considered a new disease- specific instrument to estimate changes in health status, and an useful support in optimizing therapeutic options

    Test of candidate light distributors for the muon (g−-2) laser calibration system

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    The new muon (g-2) experiment E989 at Fermilab will be equipped with a laser calibration system for all the 1296 channels of the calorimeters. An integrating sphere and an alternative system based on an engineered diffuser have been considered as possible light distributors for the experiment. We present here a detailed comparison of the two based on temporal response, spatial uniformity, transmittance and time stability.Comment: accepted to Nucl.Instrum.Meth.

    Collisions of cold magnesium atoms in a weak laser field

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    We use quantum scattering methods to calculate the light-induced collisional loss of laser-cooled and trapped magnesium atoms for detunings up to 30 atomic linewidths to the red of the 1S_0-1P_1 cooling transition. Magnesium has no hyperfine structure to complicate the theoretical studies. We evaluate both the radiative and nonradiative mechanisms of trap loss. The radiative escape mechanism via allowed 1Sigma_u excitation is dominant for more than about one atomic linewidth detuning. Molecular vibrational structure due to photoassociative transitions to bound states begins to appear beyond about ten linewidths detuning.Comment: 4 pages with 3 embedded figure
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