1,005 research outputs found
Matter-wave 2D solitons in crossed linear and nonlinear optical lattices
It is demonstrated the existence of multidimensional matter-wave solitons in
a crossed optical lattice (OL) with linear OL in the direction and
nonlinear OL (NOL) in the direction, where the NOL can be generated by a
periodic spatial modulation of the scattering length using an optically induced
Feshbach resonance. In particular, we show that such crossed linear and
nonlinear OL allows to stabilize two-dimensional (2D) solitons against decay or
collapse for both attractive and repulsive interactions. The solutions for the
soliton stability are investigated analytically, by using a multi-Gaussian
variational approach (VA), with the Vakhitov-Kolokolov (VK) necessary criterion
for stability; and numerically, by using the relaxation method and direct
numerical time integrations of the Gross-Pitaevskii equation (GPE). Very good
agreement of the results corresponding to both treatments is observed.Comment: 8 pages (two-column format), with 16 eps-files of 4 figure
An inter model distance for clustering utility function
Conjoint Analysis is one of the most widely used techniques in the assessment of the consumer’s behaviors. This method allows to estimate the partial utility coefficients according to a statistical model linking the overall note of preference with the attribute
levels describing the stimuli. Conjoint analysis results are useful in new-product positioning and market segmentation. In this paper a cluster-based segmentation strategy based on a new metric has been proposed. The introduced distance is based on a convex linear combination of two Euclidean distances em bedding information both on the estimated parameters and on the model fitting. Market segments can be then defined according to the
proximity of the part-worth coecients and to the explicative power of the estimated models
Conjoint Analysis based methodologies for the ex-ante evaluation of regulatory impact
The activity of evaluation of Public Intervention, or Regulation activity, is actually considered from public administration as a strategic element of political and administrative action. This gives rise to the development of several methods for the ex-ante evaluation of the effects of normative regulations, both on citizens and enterprise activities and on organization and operation of Public Administrations. However, the proposed methodologies not taking into account the complexity and the multidimensionality of the phenomenon, often offer a partial and qualitative point of view. Here we propose several statistical methods based on the classical Conjoint Analysis model. Our aim is to measure and evaluate the sustainability and the expected benefits of regulation respect to different designed alternatives. Mainly, we propose to apply a strategy that - integrating the Conjoint Analysis with graphical factorial representations - allows getting several purposes such as to synthesize individual judgments and to underline the different evaluation preference structures expressed by several groups of judges. The developed methodologies will be applied on real data
Characterization of a two-transmon processor with individual single-shot qubit readout
We report the characterization of a two-qubit processor implemented with two
capacitively coupled tunable superconducting qubits of the transmon type, each
qubit having its own non-destructive single-shot readout. The fixed capacitive
coupling yields the \sqrt{iSWAP} two-qubit gate for a suitable interaction
time. We reconstruct by state tomography the coherent dynamics of the two-bit
register as a function of the interaction time, observe a violation of the Bell
inequality by 22 standard deviations after correcting readout errors, and
measure by quantum process tomography a gate fidelity of 90%
Emergency endoscopy during the SARS-CoV-2 pandemic in the north of Italy. Experience from St. Orsola University Hospital—Bologna
No abstract availabl
Benign blockage: gastric outlet obstruction due to a prolapsing gastric pedunculated polyp. Case report and literature review
NO ABSTRACT AVAILABLEAn 89-year-old woman was admitted to the emergency
department at “Ospedale Civile Umberto I” in Lugo
(Ravenna) for 1 month of vomiting, mild epigastric pain,
and postprandial diarrhea without fever. Main comorbidities
included chronic atrial fbrillation treated with a direct-acting oral anticoagulant, previous MI, hypertension, diabetes,
and hypercholesterolemia, though despite her age the patient
was autonomous in her daily activities. On admission, laboratory tests included normal WBC count, Hgb, and CRP.
Abdominal X-ray demonstrated a stomach flled by ingested
food (Fig. 1a) and difuse air–fuid levels accompanied by
abdominal distension (Fig. 1b). A surgical consultation was
requested; a CT scan was performed confrming gastric distension by ingested food (Fig. 2).
Since gastric outlet obstruction was suspected, the patient
was hospitalized in a medical unit, treated with NPO and
IV fuids. After 2 weeks, a second surgical consultation was
requested due to the recurrence of clinical symptoms with
unchanged laboratory tests. An upper GI series reported
normal gastric and duodenal transit (Fig. 3) while colonoscopy was negative. The patient underwent EGD that showed
a 4-cm pedunculated polyp situated in the gastric antrum;
the polyp prolapsed into the duodenal bulb creating a “ball
valve”-type intermittent obstruction. Biopsy was consistent
with a hyperplastic polyp which was endoscopically resected
(Fig. 4a–c). The fnal histological report confrmed a benign
lesion; the patient was discharged from the hospital without
any further invasive treatment in good general condition
Vortex generation in stirred binary Bose-Einstein condensates
The dynamical vortex production, with a trap-confining time-dependent stirred
potential, is studied by using mass-imbalanced cold-atom coupled Bose-Einstein
condensates (BEC). The vortex formation is explored by considering that both
coupled species are confined by a pancake-like harmonic trap, slightly modified
elliptically by a time-dependent periodic potential, with the characteristic
frequency enough larger than the transversal trap frequency. The approach is
applied to the experimentally accessible binary mixtures Rb-Cs
and Rb-Rb, which allow us to verify the effect of mass
differences in the dynamics. For both species, the time evolutions of the
respective energy contributions, together with associated velocities, are
studied in order to distinguish turbulent from non-turbulent flows. By using
the angular momentum and moment of inertia mean values, effective classical
rotation frequencies are suggested, which are further considered within
simulations in the rotating frame without the stirring potential. Spectral
analysis is also provided for both species, with the main focus being the
incompressible kinetic energies. In the transient turbulent regime, before
stable vortex patterns are produced, the characteristic Kolmogorov
behavior is clearly identified for both species at intermediate momenta
above the inverse Thomas-Fermi radial positions, further modified by the
universal scaling at momenta higher than the inverse of the respective
healing lengths.
Emerging from the mass-imbalanced comparison, relevant is to observe that, as
larger is the mass difference, much faster is the dynamical production of
stable vortices.Comment: 17 pages, 16 figure
Dissipative Dynamics of Matter Wave Soliton in Nonlinear Optical Lattice
Dynamics and stability of solitons in two-dimensional (2D) Bose-Einstein
condensates (BEC), with low-dimensional (1D) conservative plus dissipative
nonlinear optical lattices are investigated. In the case of focusing media
(with attractive atomic systems) the collapse of the wave packet is arrested by
the dissipative periodic nonlinearity. The adiabatic variation of the
background scattering length leads to metastable matter-wave solitons.
When the atom feeding mechanism is used, a dissipative soliton can exist in
focusing 2D media with 1D periodic nonlinearity. In the defocusing media
(repulsive BEC case) with harmonic trap in one dimension and one dimensional
nonlinear optical lattice in other direction, the stable soliton can exist.
This prediction of variational approach is confirmed by the full numerical
simulation of 2D Gross-Pitaevskii equation.Comment: 9 pages, 8 figure
Effect of a moderately hypoenergetic Mediterranean diet and exercise program on body cell mass and cardiovascular risk factors in obese women
Objective: To assess the effects of a moderately hypoenergetic Mediterranean diet (MHMD) and exercise program on body cell mass (BCM) and cardiovascular disease risk factors in obese women. Subjects/Methods: Forty-seven obese women, 39.7 +/- 13.2 years of age, with a body mass index (BMI) 30.7 +/- 6.0 kg/m(2), completed the study. The following were measured at baseline, 2 and 4 months: BCM, BCM index (BCMI), body weight, BMI, fat-free mass (FFM), fat mass (FM), total body water (TBW), extracellular water (ECW) and intracellular water (ICW) using bioelectrical impedance analysis; fasting blood glucose (FBG), serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and triglyceride (TG) concentrations; systolic (SBP) and diastolic (DBP) blood pressure. Results: Body weight, BMI, FM, TC and TG significantly decreased (P<0.001; P<0.002 (TG)) at 2 and 4 months. FFM, TBW, ECW, FBG and DBP significantly decreased at 2 months (P<0.05 (FFM); P<0.001). LDL-C significantly decreased (P<0.001), while HDL-C significantly increased (P<0.002) at 4 months. BCM, BCMI, ICW and SBP remained stable over time. Conclusion: BCM was preserved and cardiovascular disease risk factors improved in obese women placed on a MHMD and exercise program for 4 months
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