Partial (13)C isotopic enrichment of nucleoside monophosphates: useful reporters for NMR structural studies

Analysis of the (13)C isotopic labeling patterns of nucleoside monophosphates (NMPs) extracted from Escherichia coli grown in a mixture of C-1 and C-2 glucose is presented. By comparing our results to previous observations on amino acids grown in similar media, we have been able to rationalize the labeling pattern based on the well-known biochemistry of nucleotide biosynthesis. Except for a few notable absences of label (C4 in purines and C3′ in ribose) and one highly enriched site (C1′ in ribose), most carbons are randomly enriched at a low level (an average of 13%). These sparsely labeled NMPs give less complex NMR spectra than their fully isotopically labeled analogs due to the elimination of most (13)C–(13)C scalar couplings. The spectral simplicity is particularly advantageous when working in ordered systems, as illustrated with guanosine diphosphate (GDP) bound to ADP ribosylation factor 1 (ARF1) aligned in a liquid crystalline medium. In this system, the absence of scalar couplings and additional long-range dipolar couplings significantly enhances signal to noise and resolution

Determinants of Real House Price Dynamics

We explore the dynamics of real house prices by estimating serial correlation and mean reversion coefficients from a panel data set of 62 metro areas from 1979-1995. The serial correlation and reversion parameters are then shown to vary cross sectionally with city size, real income growth, population growth, and real construction costs. Serial correlation is higher in metro areas with higher real income, population growth and real construction costs. Mean reversion is greater in large metro areas and faster-growing cities with lower construction costs. Empirically, substantial overshooting of prices can occur in high real construction cost areas, which have high serial correlation and low mean reversion, such as the coastal cities of Boston, New York, San Francisco, Los Angeles and San Diego.

Gamma–ray spectroscopy with single–carrier collection in high–resistivity semiconductors

With the standard plane–parallel configuration of semiconductor detectors, good γ–ray spectra can only be obtained when both electrons and holes are completely collected. We show by calculations (and experiments) that with contacts of hemispherical configuration one can obtain γ–ray spectra of adequate resolution and with signal heights of nearly full amplitude even when only one type of carrier is collected. Experiments with CdTe detectors for which the µτ product for electrons is about 10^(3) times that of the holes confirm these calculations. The adoption of hemispherical contacts thus widens the range of high–resistivity semiconductors potentially acceptable for γ–ray detection at room temperature

Evidence for a Galactic gamma ray halo

We present quantitative statistical evidence for a $\gamma$-ray emission halo surrounding the Galaxy. Maps of the emission are derived. EGRET data were analyzed in a wavelet-based non-parametric hypothesis testing framework, using a model of expected diffuse (Galactic + isotropic) emission as a null hypothesis. The results show a statistically significant large scale halo surrounding the center of the Milky Way as seen from Earth. The halo flux at high latitudes is somewhat smaller than the isotropic gamma-ray flux at the same energy, though of the same order (O(10^(-7)--10^(-6)) ph/cm^2/s/sr above 1 GeV).Comment: Final version accepted for publication in New Astronomy. Some additional results/discussion included, along with entirely revised figures. 19 pages, 15 figures, AASTeX. Better quality figs (PS and JPEG) are available at http://tigre.ucr.edu/halo/paper.htm

HD 152246 - a new high-mass triple system and its basic properties

Analyses of multi-epoch, high-resolution (R ~ 50.000) optical spectra of the O-type star HD 152246 (O9 IV according to the most recent classification), complemented by a limited number of earlier published radial velocities, led to the finding that the object is a hierarchical triple system, where a close inner pair (Ba-Bb) with a slightly eccentric orbit (e = 0.11) and a period of 6.0049 days revolves in a 470-day highly eccentric orbit (e = 0.865) with another massive and brighter component A. The mass ratio of the inner system must be low since we were unable to find any traces of the secondary spectrum. The mass ratio A/(Ba+Bb) is 0.89. The outer system has recently been resolved using long-baseline interferometry on three occasions. The interferometry confirms the spectroscopic results and specifies elements of the system. Our orbital solutions, including the combined radial-velocity and interferometric solution indicate an orbital inclination of the outer orbit of 112{\deg} and stellar masses of 20.4 and 22.8 solar masses. We also disentangled the spectra of components A and Ba and compare them to synthetic spectra from two independent programmes, TLUSTY and FASTWIND. In either case, the fit was not satisfactory and we postpone a better determination of the system properties for a future study, after obtaining observations during the periastron passage of the outer orbit (the nearest chance being March 2015). For the moment, we can only conclude that component A is an O9 IV star with v*sin(i) = 210 +\- 10 km/s and effective temperature of 33000 +\- 500 K, while component Ba is an O9 V object with v*sin(i) = 65 +/- 3 km/s and T_eff = 33600 +\- 600 K.Comment: 9 pages, 6 figures, accepted for publication in Astronomy and Astrophysic

The final COS-B database: In-flight calibration of instrumental parameters

A method for the determination of temporal variation of sensitivity is designed to find a set of parameters which lead to maximum consistency between the intensities derived from different observation periods. This method is briefly described and the resulting sensitivity and background variations presented

'Juggling the glass balls ...': Workplace spirituality in women leaders

This qualitative study explored workplace spirituality in women leadership in higher education institutions (HEIs). Interviews were conducted with women leaders of the Higher Education Research Service network across eight institutions. Observations were made in one organisation. Findings show that women leaders are highly aware of their spirituality and religious affiliation which influence their work and work spirituality. Workplace spirituality includes how women leaders approach life and work, how spirituality expands their concept of religion and how the interwoven concepts of spirituality and religion help them to manage their work optimally. The study was limited to a relatively small sample size of 23 women leaders and was further bound to the qualitative research methodology. This study provides valuable insights into workplace spirituality regarding women leaders in South African HEIs. The findings provide a base for future research on women leaders in organisations and for leadership training of women within HEIs.

Precise location of Sagittarius X ray sources with a rocket-borne rotating modulation collimator

Precise location of Sagittarius X ray sources with rocket-borne rotating modulation collimato