1,111 research outputs found
Quantum engineering of atomic phase-shifts in optical clocks
Quantum engineering of time-separated Raman laser pulses in three-level
systems is presented to produce an ultra-narrow optical transition in bosonic
alkali-earth clocks free from light shifts and with a significantly reduced
sensitivity to laser parameter fluctuations. Based on a quantum artificial
complex-wave-function analytical model, and supported by a full density matrix
simulation including a possible residual effect of spontaneous emission from
the intermediate state, atomic phase-shifts associated to Ramsey and
Hyper-Ramsey two-photon spectroscopy in optical clocks are derived. Various
common-mode Raman frequency detunings are found where the frequency shifts from
off-resonant states are canceled, while strongly reducing their uncertainties
at the 10 level of accuracy.Comment: accepted for publication in PR
Two-point functions for N=4 Konishi-like operators
We compute the two-point function of Konishi-like operators up to one-loop
order, in N=4 supersymmetric Yang-Mills theory. We work perturbatively in N=1
superspace. We find the expression expected on the basis of superconformal
invariance and determine the normalization of the correlator and the anomalous
dimension of the operators to order g^2 in the coupling constant.Comment: 10 pages, 3 figures; added references and some clarifying comment
All-Optical Production of Chromium Bose-Einstein Condensates
We report on the production of ^52Cr Bose Einstein Condensates (BEC) with an
all-optical method. We first load 5.10^6 metastable chromium atoms in a 1D
far-off-resonance optical trap (FORT) from a Magneto Optical Trap (MOT), by
combining the use of Radio Frequency (RF) frequency sweeps and depumping
towards the ^5S_2 state. The atoms are then pumped to the absolute ground
state, and transferred into a crossed FORT in which they are evaporated. The
fast loading of the 1D FORT (35 ms 1/e time), and the use of relatively fast
evaporative ramps allow us to obtain in 20 s about 15000 atoms in an almost
pure condensate.Comment: 4 pages, 4 figure
Un metodo per riconoscere faglie attive sepolte mediante misure areali di radon dal suolo
Lo studio riassume i risultati di una campagna
di misure geochimiche e strutturali
condotte nel 2004 (Neri et al., 2011) e
riguarda la misurazione delle emissioni
di gas radon e thoron dal suolo effettuate lungo
il fianco orientale dell’Etna, in una zona caratterizzata
dalla presenza di numerose faglie attive.
Le elaborazioni statistiche effettuate hanno
permesso di riconoscere soglie di anomalia
dei dati geochimici, nonché la produzione di
mappe di distribuzione che hanno evidenziato
una significativa correlazione spaziale tra le
anomalie riscontrate e i principali lineamenti
tettonici. Entrambe le anomalie di radon e
thoron si trovavano in aree interessate da sismicitÃ
relativamente profonda, in particolare
in corrispondenza delle zone di intersezione tra
faglie differentemente orientate. Questo studio
conferma che la mappatura della distribuzione
di gas radon e thoron dal suolo può rivelare la
presenza di faglie nascoste da coperture recenti,
o faglie che non sono chiaramente visibili
in superficie
potential biomarkers of haemophilic arthropathy correlations with compatible additive magnetic resonance imaging scores
Introduction: Although biomarkers are useful diagnostic tools to assess joint damage in osteoarthritis and rheumatoid arthritis, few data exist for biomarkers of haemophilic arthropathy. Aim: To evaluate the association between biomarkers and compatible additive magnetic resonance imaging (MRI) scores in patients with severe haemophilia A. Methods: Patients aged 12–35 years with no history of factor VIII (FVIII) inhibitors were enrolled in a controlled, cross-sectional, multinational investigation. Patients received primary or secondary prophylaxis or on-demand treatment with FVIII and underwent MRI on four joints (two ankles, two knees). Soluble biomarkers of cartilage and bone degradation, inflammation, and angiogenesis were assessed (serum levels of C-terminal telopeptides of type I collagen [CTX-I], cartilage oligomeric matrix protein [COMP], chondroitin-sulphate aggrecan turnover 846 epitope [CS846], tissue inhibitor of metalloproteinase 1 [TIMP-1]; plasma levels of vascular endothelial growth factor [VEGF], matrix metalloproteinases 3 and 9 [MMP3, MMP9]). Relationships between biomarkers and MRI scores were evaluated using Spearman rank correlation. Results: Biomarkers were assessed in 117 of 118 per-protocol patients. Mean and median CTX-I, COMP, TIMP-1, MMP3, MMP9, and VEGF values were within normal ranges (reference range not available for CS846 in healthy volunteers). No correlations between biomarkers and MRI scores were found, with the exception of CS846, which showed significant correlation in a subgroup of 22 on-demand patients (r = 0.436; P = 0.04). Conclusions: Compatible additive MRI scores showed no clear correlations with any of the potential biomarkers for haemophilic arthropathy in the overall population. CS846 levels were significantly correlated with MRI scores in patients treated on demand. (Less
Un metodo per riconoscere faglie attive sepolte mediante misure areali di radon dal suolo
Lo studio riassume i risultati di una campagna
di misure geochimiche e strutturali
condotte nel 2004 (Neri et al., 2011) e
riguarda la misurazione delle emissioni
di gas radon e thoron dal suolo effettuate lungo
il fianco orientale dell’Etna, in una zona caratterizzata
dalla presenza di numerose faglie attive.
Le elaborazioni statistiche effettuate hanno
permesso di riconoscere soglie di anomalia
dei dati geochimici, nonché la produzione di
mappe di distribuzione che hanno evidenziato
una significativa correlazione spaziale tra le
anomalie riscontrate e i principali lineamenti
tettonici. Entrambe le anomalie di radon e
thoron si trovavano in aree interessate da sismicitÃ
relativamente profonda, in particolare
in corrispondenza delle zone di intersezione tra
faglie differentemente orientate. Questo studio
conferma che la mappatura della distribuzione
di gas radon e thoron dal suolo può rivelare la
presenza di faglie nascoste da coperture recenti,
o faglie che non sono chiaramente visibili
in superficie
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