Wind-Tunnel Tests of the 1/9-Scale Model of the Curtiss XP-62 Airplane with Various Vertical Tail Arrangements

The effect of various vertical tail arrangements upon the stability and control characteristics of an XP-62 fighter model was investigated. Rudder-free yaw characteristics with take-off power and flaps deflected were satisfactory after dorsal fin modifications. Directional stability was obtained with all modified vertical tails. Satisfactory rudder effectiveness resulted partly because the dual-rotation propellers produced no asymmetric yawing moments. Pedal forces in sideslips were undesirably large but may be easily reduced

Modeling genetic imprinting effects of DNA sequences with multilocus polymorphism data

Single nucleotide polymorphisms (SNPs) represent the most widespread type of DNA sequence variation in the human genome and they have recently emerged as valuable genetic markers for revealing the genetic architecture of complex traits in terms of nucleotide combination and sequence. Here, we extend an algorithmic model for the haplotype analysis of SNPs to estimate the effects of genetic imprinting expressed at the DNA sequence level. The model provides a general procedure for identifying the number and types of optimal DNA sequence variants that are expressed differently due to their parental origin. The model is used to analyze a genetic data set collected from a pain genetics project. We find that DNA haplotype GAC from three SNPs, OPRKG36T (with two alleles G and T), OPRKA843G (with alleles A and G), and OPRKC846T (with alleles C and T), at the kappa-opioid receptor, triggers a significant effect on pain sensitivity, but with expression significantly depending on the parent from which it is inherited (p = 0.008). With a tremendous advance in SNP identification and automated screening, the model founded on haplotype discovery and statistical inference may provide a useful tool for genetic analysis of any quantitative trait with complex inheritance

On Zurek's derivation of the Born rule

Recently, W. H. Zurek presented a novel derivation of the Born rule based on a mechanism termed environment-assisted invariance, or "envariance" [W. H. Zurek, Phys. Rev. Lett. 90(2), 120404 (2003)]. We review this approach and identify fundamental assumptions that have implicitly entered into it, emphasizing issues that any such derivation is likely to face.Comment: 8 pages; v2: minor clarifications added; v3: reference to Zurek's quant-ph/0405161 added. To appear in Foundations of Physics (Cushing Volume

Displacements on the Imperial, Superstition Hills, and San Andreas Faults Triggered by the Borrego Mountain Earthquake

The Borrego Mountain earthquake of April 9, 1968, triggered small but consistent surface displacements on three faults far outside the source area and zone of aftershock activity. Right-lateral displacement of 1-2 1/2 cm occurred along 22, 23, and 30 km of the Imperial, Superstition Hills, and San Andreas (Banning-Mission Creek) faults, respectively, at distances of 70, 45, and 50 km from the epicenter. Although these displacements were not noticed until 4 days after the earthquake, their association with the earthquake is suggested by the freshness of the resultant en echelon cracks at that time and by the absence of creep along most of these faults during the year before or the year after the event. Dynamic strain associated with the shaking is a more likely cause of the distant displacements than is the static strain associated with the faulting at Borrego Mountain because (1) the dynamic strain was much larger and (2) the static strain at the San Andreas fault was in the wrong sense for the observed displacement. The principal surface displacements on the Imperial fault took place within 4 days of the earthquake and may have occurred simultaneously with the passage of the seismic waves, but the possibility of delayed propagation to the surface is indicated by a 1971 event on the Imperial fault in which the surface displacement followed the triggering earthquake by 3-6 days. All three of the distant faults are "active" in that they show evidence of repeated Quaternary movement, and surface displacements occurred only along those segments where the fault trace is well delineated in surface exposures, at least in uncultivated areas. This is the first documented example of fault displacement triggered by seismic shaking far from the source area, although such displacement has probably gone undetected many previous times here and in similar tectonic environments. This phenomenon forces us to be much more conservative in estimating the probabilities of damage from surface displacements along active faults in seismic regions

Endoventricular patch plasty for dyskinetic anteroapical left ventricular aneurysm increases systolic circumferential shortening in sheep

ObjectiveEndoventricular patch plasty (Dor procedure) has gained favor as a surgical treatment for heart failure associated with large anteroapical myocardial infarction. We tested the hypotheses that the Dor procedure increases systolic circumferential shortening and longitudinal shortening in noninfarcted left ventricular regions in sheep.MethodsIn 6 male Dorsett sheep, the left anterior descending coronary artery and its second diagonal branch were ligated 40% of the distance from the apex to the base. Sixteen weeks after myocardial infarction, a Dor procedure was performed with a Dacron patch that was 50% of the infarct neck dimension. Two weeks before and 2 and 6 weeks after the Dor procedure, animals underwent magnetic resonance imaging with tissue tagging in multiple short-axis and long-axis slices. Fully three-dimensional strain analyses were performed. All 6 end-systolic strain components were compared in regions 1 cm, 2 cm, 3 cm, and 4 cm below the valves, as well as in the anterior, posterior, and lateral left ventricular walls and the interventricular septum.ResultsCircumferential shortening increased from before the Dor procedure to 6 weeks after repair in nearly every left ventricular region (13/16). The greatest regional change in circumferential shortening was found in the equatorial region or 2 cm below the base and in the posterior wall (from 9.0% to 18.4%; P < .0001). Longitudinal shortening increased 2 weeks after the Dor procedure but then returned near baseline by 6 weeks after the Dor procedure.ConclusionThe Dor procedure significantly increases systolic circumferential shortening in nearly all noninfarcted left ventricular regions in sheep