The NASA Langley laminar-flow-control experiment on a swept, supercritical airfoil: Evaluation of initial perforated configuration

The initial evaluation of a large-chord, swept, supercritical airfoil incorporating an active laminar-flow-control (LFC) suction system with a perforated upper surface is documented in a chronological manner, and the deficiencies in the suction capability of the perforated panels as designed are described. The experiment was conducted in the Langley 8-Foot Transonic Pressure Tunnel. Also included is an evaluation of the influence of the proximity of the tunnel liner to the upper surface of the airfoil pressure distribution

The NASA Langley Laminar-Flow-Control Experiment on a Swept Supercritical Airfoil: Basic Results for Slotted Configuration

The effects of Mach number and Reynolds number on the experimental surface pressure distributions and transition patterns for a large chord, swept supercritical airfoil incorporating an active Laminar Flow Control suction system with spanwise slots are presented. The experiment was conducted in the Langley 8 foot Transonic Pressure Tunnel. Also included is a discussion of the influence of model/tunnel liner interactions on the airfoil pressure distribution. Mach number was varied from 0.40 to 0.82 at two chord Reynolds numbers, 10 and 20 x 1,000,000, and Reynolds number was varied from 10 to 20 x 1,000,000 at the design Mach number

Reducing the Effects of Unequal Number of Games on Rankings

Ranking is an important mathematical process in a variety of contexts such as information retrieval, sports and business. Sports ranking methods can be applied both in and beyond the context of athletics. In both settings, once the concept of a game has been defined, teams (or individuals) accumulate wins, losses, and ties, which are then factored into the ranking computation. Many settings involve an unequal number of games between competitors. This paper demonstrates how to adapt two sports rankings methods, the Colley and Massey ranking methods, to settings where an unequal number of games are played between the teams. In such settings, the standard derivations of the methods can produce nonsensical rankings. This paper introduces the idea of including a super-user into the rankings and considers the effect of this fictitious player on the ratings. We apply such techniques to rank batters and pitchers in Major League baseball, professional tennis players, and participants in a free online social game. The ideas introduced in this paper can further the scope that such methods are applied and the depth of insight they offer

Bioelectric-calcineurin signaling module regulates allometric growth and size of the zebrafish fin

AbstractThe establishment of relative size of organs and structures is paramount for attaining final form and function of an organism. Importantly, variation in the proportions of structures frequently underlies adaptive change in morphology in evolution and maybe a common mechanism underlying selection. However, the mechanism by which growth is integrated within tissues during development to achieve proper proportionality is poorly understood. We have shown that signaling by potassium channels mediates coordinated size regulation in zebrafish fins. Recently, calcineurin inhibitors were shown to elicit changes in zebrafish fin allometry as well. Here, we identify the potassium channelkcnk5bas a key player in integrating calcineurin’s growth effects, in part through regulation of the cytoplasmic C-terminus of the channel. We propose that the interaction between Kcnk5b and calcineurin acts as a signaling node to regulate allometric growth. Importantly, we find that this regulation is epistatic to inherent mechanisms instructing overall size as inhibition of calcineurin is able to bypass genetic instruction of size as seen insofand wild-type fins, however, it is not sufficient to re-specify positional memory of size of the fin. These findings integrate classic signaling mediators such as calcineurin with ion channel function in the regulation of size and proportion during growth.</jats:p

Rating the Financial Health of U.S. Production Agriculture using Synthetic Credit Rating

Agribusiness, Agricultural and Food Policy, Production Economics,

Surgical intervention is not required for all patients with subclavian vein thrombosis

AbstractPurpose: The role of thoracic outlet decompression in the treatment of primary axillary-subclavian vein thrombosis remains controversial. The timing and indications for surgery are not well defined, and thoracic outlet procedures may be associated with infrequent, but significant, morbidity. We examined the outcomes of patients treated with or without surgery after the results of initial thrombolytic therapy and a short period of outpatient anticoagulation. Methods: Patients suspected of having a primary deep venous thrombosis underwent an urgent color-flow venous duplex ultrasound scan, followed by a venogram and catheter-directed thrombolysis. They were then converted from heparin to outpatient warfarin. Patients who remained asymptomatic received anticoagulants for 3 months. Patients who, at 4 weeks, had persistent symptoms of venous hypertension and positional obstruction of the subclavian vein, venous collaterals, or both demonstrated by means of venogram underwent thoracic outlet decompression and postoperative anticoagulation for 1 month. Results: Twenty-two patients were treated between June 1996 and June 1999. Of the 18 patients who received catheter-directed thrombolysis, complete patency was achieved in eight patients (44%), and partial patency was achieved in the remaining 10 patients (56%). Nine of 22 patients (41%) did not require surgery, and the remaining 13 patients underwent thoracic outlet decompression through a supraclavicular approach with scalenectomy, first-rib resection, and venolysis. Recurrent thrombosis developed in only one patient during the immediate period of anticoagulation. Eleven of 13 patients (85%) treated with surgery and eight of nine patients (89%) treated without surgery sustained durable relief of their symptoms and a return to their baseline level of physical activity. All patients who underwent surgery maintained their venous patency on follow-up duplex scanning imaging. Conclusion: Not all patients with primary axillary-subclavian vein thrombosis require surgical intervention. A period of observation while patients are receiving oral anticoagulation for at least 1 month allows the selection of patients who will do well with nonoperative therapy. Patients with persistent symptoms and venous obstruction should be offered thoracic outlet decompression. Chronic anticoagulation is not required in these patients. (J Vasc Surg 2000;32:57-67.

Coherent Population Trapping of Electron Spins in a Semiconductor

In high-purity n-type GaAs under strong magnetic field, we are able to isolate a lambda system composed of two Zeeman states of neutral-donor bound electrons and the lowest Zeeman state of bound excitons. When the two-photon detuning of this system is zero, we observe a pronounced dip in the excited-state photoluminescence indicating the creation of the coherent population-trapped state. Our data are consistent with a steady-state three-level density-matrix model. The observation of coherent population trapping in GaAs indicates that this and similar semiconductor systems could be used for various EIT-type experiments.Comment: 5 pages, 4 figures replaced 6/25/2007 with PRL versio

Don\u27t Be Angry with Me Darling / music by H. P. Danks; words by W. L. Gardner

https://egrove.olemiss.edu/sharris_a/1010/thumbnail.jp