The aerodynamic performance of a multi-elementhigh-lift system has a critical influence on thedirect operating cost of a subsonic civil transportaircraft. A thorough understanding of theaerodynamic characteristics of these multi-elementaerofoils and wings allows aircraft companies todesign and build more competitive aircraft withhigh-lift systems that are less complex and lighterfor given high-lift performance or that haveimproved lift and drag characteristics for givensystem complexity and weight. Flight experiments onNASA Langley's B737-100 aircraft have been conductedto further enhance the understanding of the complexflows about multi-element high-lift systems atfull-scale flight conditions. In this paper, anoverview of the flight program is provided, followedby highlights of experimental results andcomputational analysis. Measurements includedsurface pressures on the slats, main element andflap elements using flush pressure ports andpressure belts, surface shear stresses using Prestontubes, off-surface velocity distributions usingboundary layer/wake rakes, aeroelastic deformationsof the flap elements using an optical positioningsystem, and boundary layer transition detectionusing hot-film anemometers and an infrared imagingsystem. Boundary layer transition measurements onthe slat using hot-film sensors are correlated withthe flow visualisation results from an infraredimaging technique. Extensive application of severalcomputational techniques and comparisons with flightmeasurements are shown for a limited number ofcases. This program has generated an extensive setof data, much of which are still being analysed.

Let $\mathbf{A}$ be a $k$ -element algebra whose chief factor size is $c$ . We show that if $\mathbf{B}$ is in the variety generated by $\mathbf{A}$ , then any abelian chief factor of $\mathbf{B}$ that is not strongly abelian has size at most ${{c}^{k-1}}$ . This solves Problem 5 of The Structure of Finite Algebras, by D. Hobby and R. McKenzie. We refine this bound to $c$ in the situation where the variety generated by $\mathbf{A}$ omits type 1. As a generalization, we bound the size of multitraces of types 1, 2, and 3 by extending coordinatization theory. Finally, we exhibit some examples of bad behavior, even in varieties satisfying a congruence identity.

The relationship between the structure of a free ligand in solution and the structure of its bound form in a complex is of great importance to the understanding of the energetics and mechanism of molecular recognition and complex formation. In this study, we use a structure-based thermodynamic approach to study the dissociation of the complex between the toxin microcystin-LR (MLR) and the catalytic domain of protein phosphatase-1 (PP-1c) for which the crystal structure of the complex is known. We have calculated the thermodynamic parameters (enthalpy, entropy, heat capacity, and free energy) for the dissociation of the complex from its X-ray structure and found the calculated dissociation constant (4.0 × 10−11) to be in excellent agreement with the reported inhibitory constant (3.9 × 10−11). We have also calculated the thermodynamic parameters for the dissociation of 47 PP-1c:MLR complexes generated by docking an ensemble of NMR solution structures of MLR onto the crystal structure of PP-1c. In general, we observe that the lower the root-mean-square deviation (RMSD) of the docked complex (compared to the X-ray complex) the closer its free energy of dissociation (ΔG°d) is to that calculated from the X-ray complex. On the other hand, we note a significant scatter between the ΔG°d and the RMSD of the docked complexes. We have identified a group of seven docked complexes with ΔG°d values very close to the one calculated from the X-ray complex but with significantly dissimilar structures. The analysis of the corresponding enthalpy and entropy of dissociation shows a compensation effect suggesting that MLR molecules with significant structural variability can bind PP-1c and that substantial conformational flexibility in the PP-1c:MLR complex may exist in solution.

We have undertaken a study of 35 patients with i(Xq) to determine whether those that are maternally derived originate by similar mechanisms to those that are paternally derived. Isochromosome formation is not associated with increased parental age and >90% of i(Xq) contain proximal Xp sequences suggesting that centromere misdivision is not a common mechanism of formation. Our results indicate that the majority of i(Xq) originate from a single X chromosome and the usual mechanisms of formation do not appear to differ according to the parent of origin.