Distribution of reflection eigenvalues in many-channel chaotic cavities with absorption

The reflection matrix R=S^{\dagger}S, with S being the scattering matrix, differs from the unit one, when absorption is finite. Using the random matrix approach, we calculate analytically the distribution function of its eigenvalues in the limit of a large number of propagating modes in the leads attached to a chaotic cavity. The obtained result is independent on the presence of time-reversal symmetry in the system, being valid at finite absorption and arbitrary openness of the system. The particular cases of perfectly and weakly open cavities are considered in detail. An application of our results to the problem of thermal emission from random media is briefly discussed.Comment: 4 pages, 2 figures; (Ref.[5b] added, appropriate modification in text

Entanglement and localization of wavefunctions

We review recent works that relate entanglement of random vectors to their localization properties. In particular, the linear entropy is related by a simple expression to the inverse participation ratio, while next orders of the entropy of entanglement contain information about e.g. the multifractal exponents. Numerical simulations show that these results can account for the entanglement present in wavefunctions of physical systems.Comment: 6 pages, 4 figures, to appear in the proceedings of the NATO Advanced Research Workshop 'Recent Advances in Nonlinear Dynamics and Complex System Physics', Tashkent, Uzbekistan, 200

Steps to recovery: Body weight-supported treadmill training for critically ill patients: A randomized controlled trial

Purpose Early mobilization of critically ill patients improves functional recovery, but is often hampered by tubes, drains, monitoring devices and muscular weakness. A mobile treadmill with bodyweight support facilitates early mobilization and may shorten recovery time to independent ambulation as compared to usual care physiotherapy alone. Materials and methods Single center RCT, comparing daily bodyweight supported treadmill training (BWSTT) with usual care physiotherapy, in patients who had been or were mechanically ventilated (≥48 h) with ≥MRC grade 2 quadriceps muscle strength. BWSTT consisted of daily treadmill training in addition to usual care physiotherapy (PT). Primary outcome was time to independent ambulation measured in days, using the Functional Ambulation Categories (FAC-score: 3). Secondary outcomes included hospital length of stay and serious adverse events. Results The median (IQR) time to independent ambulation was 6 (3 to 9) days in the BWSTT group (n = 19) compared to 11 (7 to 23) days in the usual care group (n = 21, p = 0.063). Hospital length of stay was significantly different in favour of the BWSTT group (p = 0.037). No serious adverse events occurred. Interpretation BWSTT seems a promising intervention to enhance recovery of ambulation and shorten hospital length of stay of ICU patients, justifying a sufficiently powered multicenter RCT. Trial registration number: Dutch Trial Register ID: NTR6943

Gender and grade differences in upper elementary school children’s descriptive and evaluative self-statements and self-esteem

Gender and developmental differences in self-description, self-evaluation and self-esteem were investigated using 957 elementary school children in grades 3 to 7. Gender differences were found for six of the seven descriptive statements and for five of the seven evaluative statements. The major gender stereotypical findings from previous studies were replicated. Boys reported higher scores than girls on descriptive and evaluative statements about their physical abilities and mathematics, while girls reported higher scores on descriptive and evaluative statements about reading. Declines over time were noted for all self-evaluations except having good relations with peers and for global self-esteem, providing some support for the notion that the decline in self-concepts and self-esteem may be attributed to the children's perceptions of themselves becoming more accurate and less egocentric in line with their cognitive capacity to integrate external feedback realistically