Wildness Explored

In undertaking this project our purpose was rather vague. We wanted to make a very general study of man\u27s relationship to his environment from both a practical and philosophical standpoint. Such topics as eatable wild foods, wilderness survival, and the need for wilderness preservation have been investigated. Several books have been read in each of these areas and in addition we have made several field trips. We have looked over three or four proposed wilderness areas in Arkansas and Missouri but have become most familiar with the Caney Creek area in western Arkansas. Besides making several day hikes, we camped out for four days in the Caney Creek area during the spring of 1974. The pictures in this notebook were taken while we were on this outing. The results of the project have been very broad and general and have served as a means rather then an ends in itself. In other words; our project has made us more aware of our natural surroundings and served as an initiative for our continuing to develop a healthy and meaningful relationship with our environment

Molecular dynamics simulation of mechanical behavior of nanoporous copper foams

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2006.Includes bibliographical references (leaves 43-44).Metallic foams have a variety of unique mechanical properties that make them prime candidates for many different applications. Recent developments in manufacturing have allowed for the creation of nanoporous foams but still relatively little is known about foam behavior on the nano-scale. To determine if macro-scale metallic foam theory scaled appropriately to nanoporous foams, the mechanical behavior of nanoporous copper was simulated. Molecular dynamics (MD) simulations were performed at room temperature using the Mishin potential on tetrakaidecahedron foam structures. In closed-celled foams close agreement is observed between simulated Young's moduli and constitutive theory. Nanoporous closed-celled foams also show mechanical failure mechanisms similar to those seen on the macro-scale.by Charles Cantrell.S.B

Antimycobacterial Natural Products From Higher Plants.

Two-hundred and thirty crude organic extracts from 118 plant species distributed among ten families of higher plants have been evaluated for antimycobacterial activity against Mycobacterium tuberculosis (H\sb{37}Rv) and M. avium using the BACTEC 460 radiorespirometric assay. At 100 $\mu$g/ml, twenty-four and ten of the extracts caused more than 95% inhibition of growth of M. tuberculosis and M. avium, respectively. Bioactive chromatographic fractions of Borrichia frutescens (Asteraceae) provided two new triterpenes and one known cycloartenol. In radiorespirometric bioassays against M. tuberculosis, the new (24R)-24,25-epoxycycloartan-3-one and the known (24R)-24,25-epoxycycloartan-3$\beta$-ol exhibited minimum inhibitory concentrations (MICs) of 8 $\mu$g/ml. In contrast, the new (23R)-3-oxolanosta-8,24-dien-23-ol showed no significant inhibition at 128 $\mu$g/ml. In an attempt to study the structural dependence of antimycobacterial activity of the highly active guaianolide dehydrocostus lactone (MICs of 2 and 16 $\mu$g/ml against Mycobacterium tuberculosis and M. avium, respectively) and its derivatives, and to determine configurational and possible conformational effects upon activity, m-chloroperoxybenzoic acid oxidations of dehydrocostus lactone were performed. Three new monoepoxides, one previously synthesized diepoxide, and two new diepoxides were obtained, all of which showed strongly reduced antimycobacterial activity. Antimycobacterial root extracts of Inula helenium and Rudbeckia subtomentosa were chemically investigated. Chromatographic fractions of active root extracts of I. helenium provided the known eudesmanolides alantolactone, isoalantolactone, and 11$\alpha$H, 13-dihydroisoalantolactone. Active fractions from root extracts of R. subtomentosa gave the known alloalantolactone and 3-oxoalloalantolactone. All natural and semisynthetic eudesmanolides were tested for biological activity against M. tuberculosis and demonstrated MICs ranging from 8 $\mu$g/ml for 5,6$\alpha$-epoxyalantolactone to $\u3e$128 $\mu$g/ml for 11,13-dihydroisoalantolactone and 11,13-dihydroxyalantolactone. Methanol extracts of fruits of Melia volkensii were chemically investigated and shown to contain two new triterpenes and the known triterpenoid kulonate. The structures of the new 12$\beta$-hydroxykulactone and 6$\beta$-hydroxykulactone were elucidated by 1D and 2D NMR experiments and FABMS studies. All three triterpenes exhibited significant activity against M. tuberculosis with MICs ranging from 4 $\mu$g/ml to 16 $\mu$g/ml

Evidence for a black-hole in the X-ray transient XTE J1859+226

We present the results of time-resolved optical photometry and spectroscopy of the X-ray transient XTE J1859+226 (V406 Vul). Photometric observations taken during 2000 and 2008 reveals the presence of the secondary star's ellipsoidal modulation. Further photometry obtained in 2010 shows the system ~1 mag brighter than its quiescence level and the ellipsoidal modulation diluted by strong flaring activity. Spectroscopic data obtained with the 10.4-m GTC in 2010 reveals radial velocity variations of ~500 km/s over 3 h. A simultaneous fit to the photometry and spectroscopy using sinusoids to represent the secondary star's ellipsoidal and radial velocity variations, yields an orbital period of 6.58+-0.05 h and a secondary star's radial velocity semi-amplitude of K_2= 541+-70 km/s. The implied mass function is f(M)=4.5+-0.6 Msun, significantly lower than previously reported but consistent with the presence of a black hole in XTE J1859+226. The lack of eclipses sets an upper limit to the inclination of 70 degrees which yields a lower limit to the black hole mass of 5.42 Msun.Comment: Accepted for publication in MNRAS. Contains 5 pages and 4 figure