Universal three-body recombination and Efimov resonances in an ultracold Li-Cs mixture

We study Efimov resonances via three-body loss in an ultracold two-component gas of fermionic $^6$Li and bosonic $^{133}$Cs atoms close to a Feshbach resonance at 843~G, extending results reported previously [Pires \textit{et al.}, Phys. Rev. Lett. 112, 250404 (2014)] to temperatures around 120~nK. The experimental scheme for reaching lower temperatures is based upon compensating the gravity-induced spatial separation of the mass-imbalanced gases with bichromatic optical dipole traps. We observe the first and second excited Li-Cs-Cs Efimov resonance in the magnetic field dependence of the three-body event rate constant, in good agreement with the universal zero-range theory at finite temperature [Petrov and Werner, Phys. Rev. A 92, 022704 (2015)]. Deviations are found for the Efimov ground state, and the inelasticity parameter $\eta$ is found to be significantly larger than those for single-species systems

Diagnostics and control of wavenumber stability and purity of tunable diode lasers relevant to their use as local oscillators in heterodyne systems

Initial operation of the tunable diode lasers (TDL) showed that it was not possible to adjust the wavenumber to one selected a priori in the TDL tuning range. During operation, the operating point would change by 0.1/cm over the longer term with even larger changes occurring during some thermal cycles. Most changes during thermal cycling required using lower temperatures and higher currents to reach the former wavenumber (when it could be reached). In many cases, an operating point could be selected by changing TDL current and temperature to give both the desired wavenumber and most of the power in a single mode. The selection procedure had to be used after each thermal cycling. Wavenumber nonlinearities of about 10% over a 0.5 cm tuning range were observed. Diagnostics of the single mode selected by a grating monochromator showed wavenumber fine structure under certain operating conditions. The characteristics due to the TDL environment included short term wavenumber stability, the instrument lineshape function, and intermediate term wavenumber stability

Fracture risk in systemic lupus erythematosus patients over 28 years

OBJECTIVES: Chronic glucocorticoid use is complicated by osteoporosis and increases the risk of fragility fractures. EULAR guidelines on SLE management recommend reducing chronic glucocorticoid dosage to ≤7.5 mg/day to minimize this risk. We examined the relationship of glucocorticoid dose to fragility fracture risk in a cohort of SLE patients. METHODS: Retrospective analysis of SLE patients attending University College Hospital over 28 years was undertaken. Collected data included consecutive steroid dose, dual-energy X-ray absorptiometry scans and fragility fractures. RESULTS: We collected data on 250 patients with a median of 17 years' follow-up. Fragility fractures were diagnosed in 28 (11.2%) patients and the mean ± s.d. age of first fracture was 51 ± 16 years. A total of 94% received glucocorticoids, the average dose being 6.20 mg/day. Patients with fragility fractures had a lower average daily dose (5.36 vs 6.23 mg/day) but a higher median cumulative dose (25.19 vs 20.96 g). These differences were not significant (P = 0.127 and 0.229, respectively). Some 93% of patients received vitamin D, and 85% received calcium. Cox regression analysis showed older age at SLE diagnosis, osteoporosis and secondary hyperparathyroidism were associated with fragility fractures. Glucocorticoid dose was not significantly associated with the occurrence of fragility fractures. Twenty-two patients with fractures were treated with bisphosphonates, two with denosumab and two with teriparatide. CONCLUSIONS: We found no significant association between glucocorticoid treatment and fragility fractures in our group of patients; however, a prospective study including more patients not treated with CS would be necessary to confirm these results

Self-interacting dark matter and Higgs bosons in the SU(3)_C x SU(3)_L x U(1)_N model with right-handed neutrinos

We investigate the possibility that dark matter could be made from CP-even and CP- odd Higgs bosons in the SU(3)_C X SU(3)_L X U(1)_N (3-3-1) model with right-handed neutrinos. This self-interacting dark matters are stable without imposing of new symmetry and should be weak-interacting.Comment: 7 pages, Latex, To appear in Europhys. Let

Radiação fotossinteticamente ativa durante o período chuvoso em vegetação de Caatinga em regeneração na Chapada do Araripe, PE.

A radiação fotossinteticamente ativa (PAR) é importante para diferentes áreas relacionadas à fisiologia vegetal e ciências agrárias, pois está diretamente associada à produção de biomassa e a taxa de crescimento das plantas, sendo também um importante parâmetro para estudos ecológicos. Assim, o presente trabalho teve como objetivo analisar os componentes da radiação fotossinteticamente ativa (PAR) em uma área de caatinga em regeneração na Chapada do Araripe, PE. Foram utilizados dados micrometeorológicos do período de janeiro a abril de 2013 (estação chuvosa), coletados por sensores eletrônicos instalados em uma torre localizada em uma área de caatinga em regeneração em Araripina, PE. Com base nos dados medidos de radiação PAR incidente, refletida e transmitida, obteve-se a fração da radiação fotossinteticamente ativa absorvida (fPARa) e interceptada (fPARin), assim como suas relações com a radiação solar global (Rg). Observou-se que a precipitação do período foi de 473,45 mm, correspondendo a 79,62% do total anual. A radiação fotossinteticamente ativa (PARt) e a radiação global (Rg) apresentaram correlação linear, com coeficiente de determinação (r2) igual a 0,99. O valor médio de fPARa foi igual a 55%, com menor verificado em janeiro (32%) e maior no mês de abril (76%). Esses valores estão associados ao desenvolvimento vegetativo em decorrência das chuvas e podem ser utilizados para estimativa do fator de cobertura vegetal da área de estudo. Constatou-se que existe alta correlação entre a Rg e a PAR na área de caatinga em regeneração, estimando também o comportamento da fRFAi e fRAFa