The role of coherent vortices near the turbulent/non-turbulent interface in a planar jet.

The role of coherent vortices near the turbulent/non-turbulent (T/NT) interface in a turbulent plane jet is analysed by a direct numerical simulation (DNS). The coherent vortices near the jet edge consist of large-scale vortical structures (LSVSs) maintained by the mean shear and intense vorticity structures (IVSs) created by the background fluctuating turbulence field. The radius of the LSVS is equal to the Taylor micro-scale R(lsvs)≈λ, while the radius of the IVS is of the order of the Kolmogorov micro-scale R(ivs)~η. The LSVSs are responsible for the observed vorticity jump at the T/NT interface, being of the order of the Taylor micro-scale. The coherent vortices in the proximity of the T/NT interface are preferentially aligned with the tangent to the T/NT interface and are responsible for the viscous dissipation of kinetic energy near the T/NT interface and to the characteristic shape of the enstrophy viscous diffusion observed at that location.

[Factors related to sickness absenteeism among nursing personnel]. / Fatores relacionados ao absenteísmo por doença em profissionais de enfermagem.

OBJECTIVE: To analyze short-term leaves among the healthcare staff of a university hospital. METHODS: Study population included 965 nursing professionals active on 1 January 2000. Leaves up to 30 days in one year were analyzed. Sickness leaves (one-year aggregate), service demand, and diagnoses were described. Relative risk was estimated through multivariate analysis, using negative binomial distribution. RESULTS: About 65% of workers generated 1,988 appointments, of which 68.6% lead to absence from work. The greatest demand occurred among nursing technicians, women, and statutory workers (OR=1.61; 1.47; 1.53 respectively). Over half the studied population (57.6%) had at least one absence. This corresponds to 87.8% of workers who had physician appointments. These workers generated a total 1,364 leaves of absence--1.41 per worker--and 5,279 workdays were missed. Multivariate analysis was carried out considering each gender separately. An effect was found only for work regime (RR=1.45 e RR=2.43) for both men and women. CONCLUSIONS: A relationship exists between absenteeism and work regime. It is necessary to include other variables, such as time working for the company, shift, and number of children.