By scattering from a variety of acoustic phonons, a complete stiffness tensor has been determined for crystalline beta-HMX. The results are compared with recent experimental and theoretical determinations of the elastic constants and bulk modulus. Reasons for disagreement are discussed in terms of experimental limitations and anharmonic effects. The observed ordering of stiffness constants, C(1...

We show that there exists an infinite tower of fermionic symmetries in pure d=4, N=1 supergravity on an asymptotically flat background. The Ward identities associated with these symmetries are equivalent to the soft limit of the gravitino and to the statement of supersymmetry at every angle. Additionally, we show that these charges commute into charges associated with the (unextended) Bondi-Met...

This study compares the observed behavior of the F region ionosphere over Millstone Hill with calculations from the IZMIRAN model for solar minimum for the geomagnetically quiet period 23±25 June 1986, when anomalously low values of hmF 2…<200 km) were observed. We found that these low values of hmF 2 (seen as a G condition on ionograms) exist in the ionosphere due to a decrease of production r...

[1] Diurnal, seasonal, and solar activity variations of the bottomside electron density profile parameters B0 and B1, representing the F2 layer thickness and shape, are studied using a large incoherent scatter radar dataset for Millstone Hill covering the period 1976–2002. These results are compared with the latest IRI model. Our statistical study is characterized by morning and afternoon falls...

Chittagong Hill Tracts (CHT) is situated in the Southeast of Bangladesh covering about 10 per cent of the total land. It is the native hoe of 13 tribal communities and these communities have their own traditional knowledge for natural resource managements. This paper provides 8 traditional knowledge namely, folk classification of landform, land use zoning, community reserve for common resource ...

While Phoenician culture and trade networks had a significant impact on Western civilizations, we know little about the Phoenicians themselves. In 1994, a Punic burial crypt was discovered on Byrsa Hill, near the entry to the National Museum of Carthage in Tunisia. Inside this crypt were the remains of a young man along with a range of burial goods, all dating to the late 6th century BCE. Here ...

Determining the stable homotopy groups of spheres has been a vexing and fascinating problem in algebraic topology for the past 70 years. Recall • πn+k(S) is defined to be the set of homotopy classes of maps from S (the unit sphere in R) to S. The set has a natural abelian group structure. • πn+k(S) is known to be independent of n for n > k + 1. We denote this group by π k or πk(S ). • Here are ...

Experimental observations on cyclic splitting and bending by a flagellar doublet pair are modeled using forces obtained from a model for dynein mechanochemistry, based on ideas introduced by Andrew Huxley and Terrill Hill and extended previously for modeling flagellar movements. The new feature is elastic attachment of dynein to the A doublet, which allows movement perpendicular to the A double...

ONE might not immediately associate postage stamps with the promotion of mental health ?although philately as a strain-relieving pastime is not without its therapeutic value?but stamps have long since acquired a wider significance than Sir Rowland Hill could ever have envisaged. They have become established as miniature advertising posters, exemplifying on world-wide correspondence an immense v...