Effects of winglet on transonic flutter characteristics of a cantilevered twin-engine-transport wing model

A transonic model and a low-speed model were flutter tested in the Langley Transonic Dynamics Tunnel at Mach numbers up to 0.90. Transonic flutter boundaries were measured for 10 different model configurations, which included variations in wing fuel, nacelle pylon stiffness, and wingtip configuration. The winglet effects were evaluated by testing the transonic model, having a specific wing fuel and nacelle pylon stiffness, with each of three wingtips, a nonimal tip, a winglet, and a nominal tip ballasted to simulate the winglet mass. The addition of the winglet substantially reduced the flutter speed of the wing at transonic Mach numbers. The winglet effect was configuration-dependent and was primarily due to winglet aerodynamics rather than mass. Flutter analyses using modified strip-theory aerodynamics (experimentally weighted) correlated reasonably well with test results. The four transonic flutter mechanisms predicted by analysis were obtained experimentally. The analysis satisfactorily predicted the mass-density-ratio effects on subsonic flutter obtained using the low-speed model. Additional analyses were made to determine the flutter sensitivity to several parameters at transonic speeds

Slower-than-Light Spin-1/2 Particles Endowed with Negative Mass Squared

Extending in a straightforward way the standard Dirac theory, we study a quantum mechanical wave-equation describing free spinning particles --which we propose to call "Pseudotachyons" (PT's)-- which behave like tachyons in the momentum space, but like subluminal particles (v<c) in the ordinary space. This is allowed since, as it happens in every quantum theory for spin-1/2 particles, the momentum operator (that is conserved) and the velocity operator (that is not) are independent operators, which refer to independent quantities. As a consequence, at variance with ordinary Dirac particles, for PT's the average velocity is not equal to the classical velocity, but actually to the velocity "dual" of the classical velocity. The speed of PT's is therefore smaller than the speed of light. Since a lot of experimental data seems to involve a negative mass squared for neutrinos, we suggest that these particles might be PT's, travelling, because of their very small mass, at subluminal speeds very close to c. The present theory is shown to be separately invariant under the C, P, T transformations; the covariance under Lorentz transformations is also proved. Furthermore, we derive the kinematical constraints linking 4-impulse, 4-velocity and 4-polarization of free PT'sComment: LaTeX; 20 page

Ascorbic acid enhances the inhibitory effect of aspirin on neuronal cyclooxygenase-2-mediated prostaglandin E2 production.

Inhibition of neuronal cyclooxygenase-2 (COX-2) and hence prostaglandin E2 (PGE2) synthesis by non-steroidal anti-inflammatory drugs has been suggested to protect neuronal cells in a variety of pathophysiological situations including Alzheimer's disease and ischemic stroke. Ascorbic acid (vitamin C) has also been shown to protect cerebral tissue in a variety of experimental conditions, which has been attributed to its antioxidant capacity. In the present study, we show that ascorbic acid dose-dependently inhibited interleukin-1beta (IL-1beta)-mediated PGE2 synthesis in the human neuronal cell line, SK-N-SH. Furthermore, in combination with aspirin, ascorbic acid augmented the inhibitory effect of aspirin on PGE2 synthesis. However, ascorbic acid had no synergistic effect along with other COX inhibitors (SC-58125 and indomethacin). The inhibition of IL-1beta-mediated PGE2 synthesis by ascorbic acid was not due to the inhibition of the expression of COX-2 or microsomal prostaglandin E synthase (mPGES-1). Rather, ascorbic acid dose-dependently (0.1-100 microM) produced a significant reduction in IL-1beta-mediated production of 8-iso-prostaglandin F2alpha (8-iso-PGF2alpha), a reliable indicator of free radical formation, suggesting that the effects of ascorbic acid on COX-2-mediated PGE2 biosynthesis may be the result of the maintenance of the neuronal redox status since COX activity is known to be enhanced by oxidative stress. Our results provide in vitro evidence that the neuroprotective effects of ascorbic acid may depend, at least in part, on its ability to reduce neuronal COX-2 activity and PGE2 synthesis, owing to its antioxidant properties. Further, these experiments suggest that a combination of aspirin with ascorbic acid constitutes a novel approach to render COX-2 more sensitive to inhibition by aspirin, allowing an anti-inflammatory therapy with lower doses of aspirin, thereby avoiding the side effects of the usually high dose aspirin treatment

Big brother is watching - using digital disease surveillance tools for near real-time forecasting

Abstract for the International Journal of Infectious Diseases 79 (S1) (2019).https://www.ijidonline.com/article/S1201-9712(18)34659-9/abstractPublished versio

Quantitative comparisons on hand motor functional areas determined by resting state and task BOLD fMRI and anatomical MRI for pre-surgical planning of patients with brain tumors

AbstractFor pre-surgical planning we present quantitative comparison of the location of the hand motor functional area determined by right hand finger tapping BOLD fMRI, resting state BOLD fMRI, and anatomically using high resolution T1 weighted images. Data were obtained on 10 healthy subjects and 25 patients with left sided brain tumors. Our results show that there are important differences in the locations (i.e., >20mm) of the determined hand motor voxels by these three MR imaging methods. This can have significant effect on the pre-surgical planning of these patients depending on the modality used. In 13 of the 25 cases (i.e., 52%) the distances between the task-determined and the rs-fMRI determined hand areas were more than 20mm; in 13 of 25 cases (i.e., 52%) the distances between the task-determined and anatomically determined hand areas were >20mm; and in 16 of 25 cases (i.e., 64%) the distances between the rs-fMRI determined and anatomically determined hand areas were more than 20mm. In just three cases, the distances determined by all three modalities were within 20mm of each other. The differences in the location or fingerprint of the hand motor areas, as determined by these three MR methods result from the different underlying mechanisms of these three modalities and possibly the effects of tumors on these modalities

Strange Quarks Nuggets in Space: Charges in Seven Settings

We have computed the charge that develops on an SQN in space as a result of balance between the rates of ionization by ambient gammas and capture of ambient electrons. We have also computed the times for achieving that equilibrium and binding energy of the least bound SQN electrons. We have done this for seven different settings. We sketch the calculations here and give their results in the Figure and Table II; details are in the Physical Review D.79.023513 (2009).Comment: Six pages, one figure. To appear in proceedings of the 2008 UCLA coference on dark matter and dark energ