Progress and Problems in Recent Trade Bead Research

Thirty years have passed since the late Richard G. Conn presented this paper at the conference of the Canadian Archaeological Association in Winnipeg, March 8-9, 1968. It is presented here to show us how far we have come and how far we still have to go

"Relation of railway companies to state boards of health" .

16 p

AAOmega spectroscopy of 29 351 stars in fields centered on ten Galactic globular clusters

Galactic globular clusters have been pivotal in our understanding of many astrophysical phenomena. Here we publish the extracted stellar parameters from a recent large spectroscopic survey of ten globular clusters. A brief review of the project is also presented. Stellar parameters have been extracted from individual stellar spectra using both a modified version of the Radial Velocity Experiment (RAVE) pipeline and a pipeline based on the parameter estimation method of RAVE. We publish here all parameters extracted from both pipelines. We calibrate the metallicity and convert this to [Fe/H] for each star and, furthermore, we compare the velocities and velocity dispersions of the Galactic stars in each field to the Besan\c{c}on Galaxy model. We find that the model does not correspond well with the data, indicating that the model is probably of little use for comparisons with pencil beam survey data such as this.Comment: 6 pages, 5 figures, 4 tables. Accepted for publication in A&A. Data described in tables will be available on CDS (at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/530/A31) once publishe

A study to explore the use of orbital remote sensing to determine native arid plant distribution

The author has identified the following significant results. It is possible to determine, from ERTS imagery, native arid plant distribution. Using techniques of multispectral masking and extensive fieldwork, three native vegetation communities were defined and mapped in the Avra Valley study area. A map was made of the Yuma area with the aid of ground truth correlations between areas of desert pavement visible on ERTS images and unique vegetation types. With the exception of the Yuma soil-vegetation correlation phenomena, only very gross differentiations of desert vegetation communities can be made from ERTS data. Vegetation communities with obvious vegetation density differences such as saguaro-paloverde, creosote bush, and riparian vegetation can be separated on the Avra Valley imagery while more similar communities such as creosote bush and saltbush could not be differentiated. It is suggested that large differences in vegetation density are needed before the signatures of two different vegetation types can be differentiated on ERTS imagery. This is due to the relatively insignificant contribution of vegetation to the total radiometric signature of a given desert scene. Where more detailed information concerning the vegetation of arid regions is required, large scale imagery is appropriate

Gemini and Lowell observations of 67P/Churyumov−Gerasimenko during the <i>Rosetta</i> mission

We present observations of comet 67P/Churyumov−Gerasimenko acquired in support of the Rosetta mission. We obtained usable data on 68 nights from 2014 September until 2016 May, with data acquired regularly whenever the comet was observable. We collected an extensive set of near-IR J, H and Ks data throughout the apparition plus visible-light images in g', r', i' and z' when the comet was fainter. We also obtained broad-band R and narrow-band CN filter observations when the comet was brightest using telescopes at Lowell Observatory. The appearance was dominated by a central condensation and the tail until 2015 June. From 2015 August onwards, there were clear asymmetries in the coma, which enhancements revealed to be due to the presence of up to three features (i.e. jets). The features were similar in all broad-band filters; CN images did not show these features but were instead broadly enhanced in the southeastern hemisphere. Modelling using the parameters from Vincent et al. replicated the dust morphology reasonably well, indicating that the pole orientation and locations of active areas have been relatively unchanged over at least the last three apparitions. The dust production, as measured by A(0°)fρ peaked ∼30 d after perihelion and was consistent with predictions from previous apparitions. A(0°)fρ as a function of heliocentric distance was well fitted by a power law with slope −4.2 from 35 to 120 d post-perihelion. We detected photometric evidence of apparent outbursts on 2015 August 22 and 2015 September 19, although neither was discernible morphologically in this data set

Optimization of a Ribosomal Structural Domain by Natural Selection

A conserved, independently folding domain in the large ribosomal subunit consists of 58 nt of rRNA and a single protein, L11. The tertiary structure of an rRNA fragment carrying the Escherichia coli sequence is marginally stable in vitro but can be substantially stabilized by mutations found in other organisms. To distinguish between possible reasons why natural selection has not evolved a more stable rRNA structure in E. coli, mutations affecting the rRNA tertiary structure were assessed for their in vitro effects on rRNA stability and L11 affinity (in the context of an rRNA fragment) or in vivo effects on cell growth rate and L11 content of ribosomes. The rRNA fragment stabilities ranged from -4 to +9 kcal/mol relative to the wild-type sequence. Variants in the range of -4 to +5 kcal/mol had almost no observable effect in vivo, while more destabilizing mutations (\u3e7 kcal/mol) were not tolerated. The data suggest that the in vivo stability of the complex is roughly -6 kcal/mol and that any single tertiary interaction is dispensable for function as long as a minimum stability of the complex is maintained. On the basis of these data, it seems that the evolution of this domain has not been constrained by inherent structural or functional limits on stability. The estimated stability corresponds to only a few ribosomes per bacterial cell dissociated from L11 at any time; thus the selective advantage for any further increase in stability may be so small as to be outweighed by other competing selective pressures

Monellin (MNEI) at 1.15 Å resolution

The crystal structure of the sweet protein MNEI at 1.15 Å resolution reveals networks of alternate conformations and stably bound negative ions