ABSTRACT
The Double Asteroid Redirection Test (DART) had an impact with Dimorphos (a satellite of the asteroid Didymos) on 26 September 20221. Ground-based observations showed that the Didymos system brightened by a factor of 8.3 after the impact because of ejecta, returning to the pre-impact brightness 23.7 days afterwards2. Hubble Space Telescope observations made from 15 minutes after impact to 18.5 days after, with a spatial resolution of 2.1 kilometres per pixel, showed a complex evolution of the ejecta3, consistent with other asteroid impact events. The momentum enhancement factor, determined using the measured binary period change4, ranges between 2.2 and 4.9, depending on the assumptions about the mass and density of Dimorphos5. Here we report observations from the LUKE and LEIA instruments on the LICIACube cube satellite, which was deployed 15 days in advance of the impact of DART. Data were taken from 71 seconds before the impact until 320 seconds afterwards. The ejecta plume was a cone with an aperture angle of 140 ± 4 degrees. The inner region of the plume was blue, becoming redder with increasing distance from Dimorphos. The ejecta plume exhibited a complex and inhomogeneous structure, characterized by filaments, dust grains and single or clustered boulders. The ejecta velocities ranged from a few tens of metres per second to about 500 metres per second.
ABSTRACT
A theory is developed for the emission noise at frequency ν in a quantum dot in the presence of Coulomb interactions and asymmetric couplings to the reservoirs. We give an analytical expression for the noise in terms of the various transmission amplitudes. Including the inelastic scattering contribution, it can be seen as the analog of the Meir-Wingreen formula for the current. A physical interpretation is given on the basis of the transmission of one electron-hole pair to the concerned reservoir where it emits an energy after recombination. We then treat the interactions by solving the self-consistent equations of motion for the Green functions. The results for the noise derivative versus eV show a zero value until eV=hν, followed by a Kondo peak in the Kondo regime, in good agreement with recent measurements in carbon nanotube quantum dots.
ABSTRACT
We study the effects of Kondo correlations on the transmission phase shift of a quantum dot coupled to two leads in comparison with the experimental determinations made by Aharonov-Bohm (AB) quantum interferometry. We propose here a theoretical interpretation of these results based on scattering theory combined with Bethe ansatz calculations. We show that there is a factor of 2 difference between the phase of the S-matrix responsible for the shift in the AB oscillations and the one controlling the conductance. Quantitative agreement is obtained with experimental results for two different values of the coupling to the leads.
ABSTRACT
The target of this work is to evaluate the translabial ultrasonography (US) reliability as valid alternative to chain cystography in the pre and post operative assessment of patients with stress urinary incontinence (SUI). From June 1996 to May 1999, we studied 448 patients ranging in age from 35 to 90 years old with SUI from defect of anatomic support. Patients underwent translabial ultrasonography. The translabial US was performed with the patient in lithotomic position using a linear 7.5 MHz probe. The bladder was slightly filled, and the probe positioned longitudinally at the introitus to evaluate downwards and posterior rotation of bladder neck and urethra in basal conditions as well as during the abdominal strain. The evaluation of the anterior urethral angle of the 448 patients who underwent translabial US showed that, during the abdominal strain, all the patients with SUI had a very significative rotation of the urethral axis compared to continent women. Translabial US is a quick, simple, reliable non-invasive procedure. It may be used routinely for the pre and post-operative evaluation of anti-incontinence surgery.
