1,562 research outputs found
Multichronometric evidence for an in-situ origin of the ultrahigh-pressure metamorphic terrane of Dabieshan, China
No full textU-Pb zircon data on gneisses indicate a Late Proterozoic protolith at approx. 700 Ma at Bixiling and a Late Archean to Early Proterozoic for the Shuanghe sheet within the ultrahigh-pressure metamorphic terrane of Dabieshan (China). U-Pb zircon and Sm-Nd dates on the gneisses of the Shuanghe sheet constrain a metamorphic peak at approx. 230 Ma. Rb-Sr and 40Ar-39Ar analyses of phengite from five gneisses in the Bixiling Complex yield ages at 198212 Ma, overlapping the 190220-Ma age on eclogites. The host gneisses record a similar metamorphic evolution as the coesite-bearing eclogites since both the peak and the retrograde evolution were contemporaneous. This argues for an in situ tectonic relationship
IUPAC-IUGS common definition and convention on the use of the year as a derived unit of time (IUPAC Recommendations 2011)
No full textThe units of time (both abs. time and duration) most practical to use when dealing with very long times, for example, in nuclear chem. and earth and planetary sciences, are multiples of the year, or annus (a). Its proposed definition in terms of the SI base unit for time, the second (s), for the epoch 2000.0 is 1 a = 3.1556925445 × 107 s. Adoption of this definition, and abandonment of the use of distinct units for time differences, will bring the earth and planetary sciences into compliance with quantity calculus for SI and non-SI units of time
Pharmacokinetic and pharmacodynamic (PK/PD) evaluation of cefazolin in dog
No full textThe objectives of this study were to investigate the pharmacokinetics of danofloxacin and its metabolite N-desmethyldanofloxacin and to determine their concentrations in synovial fluid after administration by the intravenous, intramuscular or intragastric routes. Six adult mares received danofloxacin mesylate administered intravenously (i.v.) or intramuscularly (i.m.) at a dose of 5 mg/kg, or intragastrically (IG) at a dose of 7.5 mg/kg using a randomized Latin square design. Concentrations of danofloxacin and N-desmethyldanofloxacin were measured by UPLC-MS/MS. After i.v. administration, danofloxacin had an apparent volume of distribution (mean ± SD) of 3.57 ± 0.26 L/kg, a systemic clearance of 357.6 ± 61.0 mL/h/kg, and an elimination half-life of 8.00 ± 0.48 h. Maximum plasma concentration (Cmax) of N-desmethyldanofloxacin (0.151 ± 0.038 μg/mL) was achieved within 5 min of i.v. administration. Peak danofloxacin concentrations were significantly higher after i.m. (1.37 ± 0.13 μg/mL) than after IG administration (0.99 ± 0.1 μg/mL). Bioavailability was significantly higher after i.m. (100.0 ± 12.5%) than after IG (35.8 ± 8.5%) administration. Concentrations of danofloxacin in synovial fluid samples collected 1.5 h after administration were significantly higher after i.v. (1.02 ± 0.50 μg/mL) and i.m. (0.70 ± 0.35 μg/mL) than after IG (0.20 ± 0.12 μg/mL) administration. Monte Carlo simulations indicated that danofloxacin would be predicted to be effective against bacteria with a minimum inhibitory concentration (MIC) ≤0.25 μg/mL for i.v. and i.m. administration and 0.12 μg/mL for oral administration to maintain an area under the curve:MIC ratio ≥50
Farmacocinetica della flumequina nella capra. Dati preliminari
No full textFlumequine kinetics, administered intravenously (i.v.) and intramuscularly (i.m.) at 20 mg.kg-1, was investigated in 6 healthy goats, and the kinetic parameters obtained related to minimal inhibitory concentrations (MIC90) reported in literature. After i.v. injection, flumequine distributed rapidly (t1/2α = 0.87 ± 0.15 h) but was eliminated slowly (t1/2β = 7.12 ± 1.27 h). After i.m. administration, peak serum level (Cmax= 7.40±0.5 μg.mL-1) and bioavailability (>90%) of the drug indicate that flumequine could have a good efficacy against systemic infections sustained by susceptible microorganisms
A Lagrangian sub-grid model for the dispersion of clouds of tracers
No full textTurbulence models are expected to satisfy the conflicting requirements of accuracy and computational efficiency. Here we discuss a new model that was recently developed in order to accurately and efficiently describe the dynamic of a clouds of tracers particles in Large Eddy Simulations of homogeneous and isotropic turbulent flows. The models incorporates the multi-scale nature of time and space turbulent velocity correlations that are essential in order to correctly reproduce the relative dispersion of multi-particle clouds. The model can be seen as an off-grid solver for the Eulerian velocity field at the positions of a given number of Lagrangian tracers that self-consistently move with it. Extensions to non homogeneous and isotropic turbulence as well as to the dynamics of particles will be discussed
Barium silicates of the Berisal Complex, Switzerland: A study in geochronology and rare-gas release systematics
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