The absolute frequency of the In(+) 5s(2) (1)S(0)5s5p (3)P(0) clock transition at 237 nm was measured with an accuracy of 1.8 parts in 10(13). Using a phase-coherent frequency chain, we compared the (1)S(0)(3)P(0) transition with a methane-stabilized HeNe laser at 3.39 microm, which was calibrated against an atomic cesium fountain clock. A frequency gap of 37 THz at the fourth harmonic of the HeNe standard was bridged by a frequency comb generated by a mode-locked femtosecond laser. The frequency of the In(+) clock transition was found to be 1,267,402,452,899.92 (0.23) kHz, the accuracy being limited by the uncertainty of the HeNe laser reference. This result represents an improvement in accuracy of more than 2 orders of magnitude over previous measurements of the line and now stands as what is to our knowledge the most accurate measurement of an optical transition in a single ion.s.
Antihistaminic drugs are commonly used as symptomatic therapy of atopic dermatitis in dogs. Unfortunately, their clinical benefit is largely unsubstantiated. In a double-blinded, placebo-controlled, cross-over trial, the influence of dimetinden and of a combination of chlorpheniramine and hydroxyzine on pruritus and lesions was evaluated in 19 dogs. They were treated with either product or a placebo orally for 14 days, each time followed by a 14-day washout period. Before and after each period, the dogs were examined and the Canine Atopic Dermatitis Extent and Severity Index (CADESI) determined by a clinician, and the pruritus and general condition by the owner. Dimetinden improved the pruritus significantly (P=0.014) but not the CADESI (P=0.087), the combination of hydroxyzine and chlorpheniramine improved the CADESI (P=0.049) and pruritus (P=0.05) significantly. Ten of 17 dogs improved by more than 25 per cent in pruritus with the combination of hydroxyzine and chlorpheniramine, 12 of 18 with dimetindenmaleate and only 2 of 19 with placebo. Antihistamines can help to reduce pruritus in atopic dogs, but in most cases, the improvement is limited and additional treatment may be needed.
A narrow transition of a single laser-cooled ion, stored in a radio-frequency trap, can serve as a reference for a frequency standard of very high accuracy and stability. For the implementation of such a system, we study the 5s 2 1 S 0 -5s5p 3 P 0 transition in In + , at a wavelength of 237 nm. This resonance has a linewidth of 0.8 Hz, with systematic frequency shifts expected to be at the mHz level. A fractional resolution of 1.3 × 10 −13 has been so far achieved, limited by the frequency instability of the clock laser used to excite the line. The absolute frequency of the 1 S 0 -3 P 0 transition was measured using the frequency comb of a mode-locked fs laser, and as a reference a methane-stabilized He-Ne laser at 3.4 µm, which was calibrated against an atomic caesium fountain clock. The transition frequency was determined as 1267 402 452 899.92 (0.23) kHz, the uncertainty being limited by the uncertainty of the He-Ne standard. The short-term frequency stability of the clock laser was recently greatly improved. With a new laser set-up a linewidth < 4 Hz (FWHM) for integration times up to 26 s was achieved, using laser platforms which actively isolate from external mechanical vibrations.
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