Origins of NASA names

Names are selected for NASA spaceflight projects and programs from various sources. Some have their foundations in mythology and astrology or legend and folklore. Some have historic connotations; others are based on a description of their mission, often resulting in an acronym. Included are names of launch vehicles, spacecraft, manned spaceflight programs, sounding rockets, and NASA field installations. This study is limited to names of approved projects through 1974; it does not include names of numerous projects which have been or are being studied or projects that were canceled or postponed before reaching actual flight

Rigidity analysis of HIV-1 protease

We present a rigidity analysis on a large number of X-ray crystal structures of the enzyme HIV-1 protease using the 'pebble game' algorithm of the software FIRST. We find that although the rigidity profile remains similar across a comprehensive set of high resolution structures, the profile changes significantly in the presence of an inhibitor. Our study shows that the action of the inhibitors is to restrict the flexibility of the beta-hairpin flaps which allow access to the active site. The results are discussed in the context of full molecular dynamics simulations as well as data from NMR experiments.Comment: 4 pages, 3 figures. Conference proceedings for CMMP conference 2010 which was held at the University of Warwic

Hartree-Fock-Bogoliubov Calculations in Coordinate Space: Neutron-Rich Sulfur, Zirconium, Cerium, and Samarium Isotopes

Using the Hartree-Fock-Bogoliubov (HFB) mean field theory in coordinate space, we investigate ground state properties of the sulfur isotopes from the line of stability up to the two-neutron dripline ($^{34-52}S$). In particular, we calculate two-neutron separation energies, quadrupole moments, and rms-radii for protons and neutrons. Evidence for shape coexistence is found in the very neutron-rich sulfur isotopes. We compare our calculations with results from relativistic mean field theory and with available experimental data. We also study the properties of neutron-rich zirconium ($^{102,104}Zr$), cerium ($^{152}Ce$), and samarium ($^{158,160}Sm$) isotopes which exhibit very large prolate quadrupole deformations.Comment: 7 pages, 6 figures, 2 tables submitted to Phys. Rev.

Letter from S. E. Wells to John Muir, 1879 Jan 15.

00825 Elizabeth. New Jersey Wed. Jan 15th. 1879. John Muir- Sir- For more than twenty five years, as opportunity offered, I have as- ked returned Californians, the name of a plant found in the Prayer Book of a relative who died at Sacramento. Having made your acquaintance through the fresh, poetic &, instructive articles in “Scribner”. I take the liberty to send a leaf, & imperfect description of the flower, - which is perhaps un- necessary — and must be very [illegible], having been pressed so many years, & fastened on paper. Stem woody – leaves irregular. Caly[illegible], probably these leaved. Corolla [illegible] a petalled. more than two inches in length, with[Page 2][in margin: their own distinctive tones? Have often listened - but without coming to any conclusion. Trusting you will excuse the intrusion - I am respectfully & enquiringly - S.E. Wells 414 West [illegible] St.]longitudinal veins – [illegible] nearly half the length of Corolla, both of a reddish brown. My uncle went “around the [illegible],” or rather through the Straits of Majellan in: [49?] — having a very quick passage, they were not likely to put in at any [port?] from which I infer the plant belongs to California – Of a complete outfit, all that evr came home was his Bible, Prayer Book, & in a very coarse, dirty cloth, a quantity of pebbles, about the [ size?] of & resembling leaves. many colors, but none white & a perfect arrow head – small white, I almost translucent — I mention this, as there may be some conn[illegible] between the two – so far as location is concerned – for in the short, rough life of a miner, there might not come many woods, in which he would give his time to the careful pressing of a flower, or the selection of curious stones. Swaying in the mt tops during a gale, was the dream of my youth – therefore the more enjoyed as the experience of another.- Do other trees than [illegible] [illegible] hav

Comparative analysis of rigidity across protein families

We present a comparative study in which 'pebble game' rigidity analysis is applied to multiple protein crystal structures, for each of six different protein families. We find that the main-chain rigidity of a protein structure at a given hydrogen bond energy cutoff is quite sensitive to small structural variations, and conclude that the hydrogen bond constraints in rigidity analysis should be chosen so as to form and test specific hypotheses about the rigidity of a particular protein. Our comparative approach highlights two different characteristic patterns ('sudden' or 'gradual') for protein rigidity loss as constraints are removed, in line with recent results on the rigidity transitions of glassy networks

Drink wise, age well; reducing alcohol related harm among people over 50: a study protocol

Background: Evidence suggests that the use of alcohol among older adults (defined as those aged 50+) has increased in recent years, with people aged 55-64 now more likely to exceed the recommended weekly guidelines than any other age group. Methods/ design: This is a quasi-experimental study with a before-after design. A postal questionnaire will be sent to 76,000 people aged 50 and over registered with a general practice in five different 'demonstration' (intervention) and control areas in the UK. Multiple interventions will then be delivered in demonstration areas across the UK. At the end of the programme, a postal questionnaire will be sent to the same individuals who completed it pre-programme to establish if there has been a reduction in alcohol use, at-risk drinking and alcohol related problems. Qualitative interviews with clients and staff will explore how the interventions were experienced; how they may work to bring about change and to identify areas for practice improvements. Discussion: This study protocol describes a multi-level, multi-intervention prevention-to-treatment programme which aims to reduce alcohol-related harm in people aged 50 and over

Model-independent measurements of the sodium magneto-optical trap's excited-state population

We present model-independent measurements of the excited-state population of atoms in a sodium (Na) magneto-optical trap (MOT) using a hybrid ion-neutral trap composed of a MOT and a linear Paul trap (LPT). We photoionize excited Na atoms trapped in the MOT and use two independent methods to measure the resulting ions: directly by trapping them in our LPT, and indirectly by monitoring changes in MOT fluorescence. By measuring the ionization rate via these two independent methods, we have enough information to directly determine the population of MOT atoms in the excited-state. The resulting measurement reveals that there is a range of trapping-laser intensities where the excited-state population of atoms in our MOT follows the standard two-level model intensity-dependence. However, an experimentally determined effective saturation intensity must be used instead of the theoretically predicted value from the two-level model. We measured the effective saturation intensity to be $I_\mathrm{se}=22.9(3)\:\textrm{mW}/\textrm{cm}^2$ for the type-I Na MOT and $I_\mathrm{se}=48.9(7)\;\textrm{mW}/\textrm{cm}^2$ for the type-II Na MOT, approximately 1.7 and 3.6 times the theoretical estimate, respectively. Lastly, at large trapping-laser intensities, our experiment reveals a clear departure from the two-level model at a critical intensity that we believe is due to a state-mixing effect, whose critical intensity can be determined by a simple power broadening model.Comment: 10 pages, 8 figure