45 research outputs found
Comment on "Prospect of optical frequency standard based on a 43Ca+ ion"
A recent evaluation of the frequency uncertainty expected for an optical
frequency standard based on a single trapped Ca ion was published in
Phys. Rev. A {\bf 72} (2005) 043404. The paper contains some interesting
information like systematic frequency shifts but fails to depict their
uncertainty, leading to confuse accuracy and precision. The conclusions about
the major contribution to the frequency shift are not consistent with the
presented calculations and omit comparisons with data published previously
Long-term stabilization of the length of an optical reference cavity
To obtain a high degree of long-term length stabilisation of an optical
reference cavity, its free-spectral range is locked by means of an accurate and
stable frequency synthesizer. The locking scheme is twofold: a laser is locked
on the N mode of a reference Fabry-Perot cavity and part of the laser
light is shifted in frequency to be in resonance with the (N+1) mode of
the cavity. This shift is generated by an acousto-optical modulator (AOM)
mounted in a double-pass scheme, matching half of the free spectral range of
the reference cavity. The resulting absolute stabilization of the length of the
cavity reaches the 10 level per second, limited by the lock transfer
properties and the frequency stability of the AOM control synthesizer
Metastable level lifetimes from electron-shelving measurements with ion clouds and single ions
The lifetime of the 3d^2D_5/2-level in singly-ionized calcium has been
measured by the electron-shelving technique on different samples of rf trapped
ions. The metastable state has been directly populated by exciting the
dipole-forbidden 4S_1/2 - 3D_5/2 transition. In ion clouds, the natural
lifetime of this metastable level has been measured to be (1095+-27) ms. For
the single-ion case, we determined a lifetime of (1152+-20) ms. The
1sigma-error bars at the 2%-level have different origins for the two kinds of
experiments: data fitting methods for lifetime measurements in an ion cloud and
control of experimental parameters for a single ion. De-shelving effects are
extensively discussed. The influence of differing approaches for the processing
of the single-ion quantum jump data on the lifetime values is shown. Comparison
with recent measurements shows excellent agreement when evaluated from a given
method
Safety, tolerability and effects on cardiometabolic risk factors of empagliflozin monotherapy in drug-naĂŻve patients with type 2 diabetes: a double-blind extension of a Phase III randomized controlled trial
BACKGROUND: To investigate the long-term efficacy and safety of empagliflozin monotherapy compared with placebo and sitagliptin in drug-naĂŻve patients with type 2 diabetes mellitus. METHODS: Of 899 patients randomized to receive empagliflozin 10 mg, empagliflozin 25 mg, placebo, or sitagliptin 100 mg once daily for 24 weeks, 615 continued in a double-blind extension trial for â„52 weeks. Exploratory endpoints included changes from baseline in HbA1c, weight and blood pressure at week 76. RESULTS: Compared with placebo, adjusted mean changes from baseline in HbA1c at week 76 were â0.78 % (95 % CI â0.94, â0.63; p < 0.001) and â0.89 % (95 % CI â1.04, â0.73; p < 0.001) for empagliflozin 10 mg and 25 mg, respectively. Compared with placebo, adjusted mean changes from baseline in weight at week 76 were â1.8 kg (95 % CI â2.4, â1.3; p < 0.001) and â2.0 kg (95 % CI â2.6, â1.5; p < 0.001) for empagliflozin 10 mg and 25 mg, respectively. Empagliflozin led to reductions in systolic blood pressure (SBP) compared with placebo in the primary analysis but not in sensitivity analyses. Compared with sitagliptin, empagliflozin 25 mg reduced HbA1c and both empagliflozin doses reduced weight and SBP. Adverse events (AEs) were reported in 76.8, 78.0, 76.4 and 72.2 % of patients on empagliflozin 10 mg, empagliflozin 25 mg, placebo and sitagliptin, respectively. Confirmed hypoglycaemic AEs (glucose â€3.9 mmol/l and/or requiring assistance) were reported in two patients (0.9 %) per treatment group. CONCLUSIONS: Empagliflozin monotherapy for â„76 weeks was well tolerated and led to sustained reductions in HbA1c and weight compared with placebo
A História da Alimentação: balizas historiogråficas
Os M. pretenderam traçar um quadro da HistĂłria da Alimentação, nĂŁo como um novo ramo epistemolĂłgico da disciplina, mas como um campo em desenvolvimento de prĂĄticas e atividades especializadas, incluindo pesquisa, formação, publicaçÔes, associaçÔes, encontros acadĂȘmicos, etc. Um breve relato das condiçÔes em que tal campo se assentou faz-se preceder de um panorama dos estudos de alimentação e temas correia tos, em geral, segundo cinco abardagens Ia biolĂłgica, a econĂŽmica, a social, a cultural e a filosĂłfica!, assim como da identificação das contribuiçÔes mais relevantes da Antropologia, Arqueologia, Sociologia e Geografia. A fim de comentar a multiforme e volumosa bibliografia histĂłrica, foi ela organizada segundo critĂ©rios morfolĂłgicos. A seguir, alguns tĂłpicos importantes mereceram tratamento Ă parte: a fome, o alimento e o domĂnio religioso, as descobertas europĂ©ias e a difusĂŁo mundial de alimentos, gosto e gastronomia. O artigo se encerra com um rĂĄpido balanço crĂtico da historiografia brasileira sobre o tema
Collisional quenching and j-mixing rate constants for the 3 D levels of Ca+
International audienceno abstrac
Investigation of a Ca+ rf stored ion cloud and observation of the forbidden S-D transitions,
International audienceno abstrac
Collisional quenching and j-mixing rate constants for the 3 D levels of Ca+
International audienceno abstrac
Investigation of a Ca+ rf stored ion cloud and observation of the forbidden S-D transitions,
International audienceno abstrac