Decontextualizing contextual inversion

Contextual inversion, introduced as an analytical tool by David Lewin, is a concept of wide reach and value in music theory and analysis, at the root of neo-Riemannian theory as well as serial theory, and useful for a range of analytical applications. A shortcoming of contextual inversion as it is currently understood, however, is, as implied by the name, that the transformation has to be defined anew for each application. This is potentially a virtue, requiring the analyst to invest the transformational system with meaning in order to construct it in the first place. However, there are certainly instances where new transformational systems are continually redefined for essentially the same purposes. This paper explores some of the most common theoretical bases for contextual inversion groups and considers possible definitions of inversion operators that can apply across set class types, effectively decontextualizing contextual inversions.Accepted manuscrip

A photometric and spectroscopic investigation of star formation in the very young open cluster NGC6383

The very young open cluster NGC 6383 centered on the O-star binary HD 159176 is an interesting place for studying the impact of early-type stars with strong radiation fields and powerful winds on the formation processes of low-mass stars. To investigate this process, it is necessary to determine the characteristics (age, presence, or absence of circumstellar material) of the population of low-mass pre-main-sequence (PMS) stars in the cluster. We obtained deep U B V (R I)_c H-alpha photometric data of the entire cluster as well as medium-resolution optical spectroscopy of a subsample of X-ray selected objects. Our spectroscopic data reveal only very weak H-alpha emission lines in a few X-ray selected PMS candidates. We photometrically identify a number of H-alpha emission candidates but their cluster membership is uncertain. We find that the fainter objects in the field of view have a wide range of extinction (up to A_V = 20), one X-ray selected OB star having A_V ~ 8. Our investigation uncovers a population of PMS stars in NGC 6383 that are probably coeval with HD 159176. In addition, we detect a population of reddened objects that are probably located at different depths within the natal molecular cloud of the cluster. Finally, we identify a rather complex spatial distribution of H-alpha emitters, which is probably indicative of a severe contamination by foreground and background stars.Comment: Accepted for publication in Astronomy & Astrophysic

Apollo mission experience

Dosimetric implications for manned space flight are evaluated by analyzing the radiation field behind the heavy shielding of a manned space vehicle on a near-earth orbital mission and how it compares with actual exposure levels recorded on Apollo missions. Emphasis shifts from flux densities and energy spectra to incident radiation and absorbed doses and dose equivalents as they are recorded within the ship at locations close to crew members

Deposition of adherent Ag-Ti duplex films on ceramics in a multiple-cathode sputter deposition system

The adhesion of Ag films deposited on oxide ceramics can be increased by first depositing intermediate films of active metals such as Ti. Such duplex coatings can be fabricated in a widely used three target sputter deposition system. It is shown here that the beneficial effect of the intermediate Ti film can be defeated by commonly used in situ target and substrate sputter cleaning procedures which result in Ag under the Ti. Auger electron spectroscopy and wear testing of the coatings are used to develop a cleaning strategy resulting in an adherent film system

MATERNAL INFLUENCES ON THE DEVELOPMENT OF INFANT ORAL BIOFILM

Purpose: The purpose was to examine the maternal influences on the development of infant oral biofim and dominant bacterial strains of at risk populations. Methods: The study used a cross-sectional design to examine factors influencing biofilm colonization and the identification of bacterial strains transmitted from mother to child. Participants were enrolled in Children’s Health Involving Parents of Greater Richmond (CHIP). Plaque and saliva samples were collected from mothers and their children ages 6-36 months. The colonized oral bacteria strains of the mother infant dyads were then compared. Oral bacterial strain identification was completed using the HOMIM Forsythe microbe identification array. Examination for concordant strains was done using the statistical boot strap shuffle in Excel. Results: Forty-one CHIP families were involved in the pilot study. Participants were predominantly non-white , less than high school education 46.3%, and their average age was 29.1 years. Mothers had a caries prevalence of 87.8% and the infant’s caries rate was 26.7%. To date n=14 pairs of the n=41 samples have been processed and analyzed using the HOMIM microarray. Twelve paired samples were not processed due to non-detectable levels of bacterial DNA. Fifteen samples are currently being processed by HOMIM Forsyth. Predominate species transferred from mother to child include S. Oralis, S. parasanguinous, S. mitis, Slakia, and S. anginosis. 425 unique strains of bacteria were analyzed on the array with a maternal concurrence rate of 33%. Conclusion: When comparing total bacterial populations in the oral environment a concurrence of transmission from mother to child was 33%. Higher rates of vertical transmission were observed in S. Oralis, S. sanguinous, and Slakia

A search for rapidly modulated emission in bright X-ray sources using the HEAO A-1 data base

A search was performed in the HEAO A-1 Data Base (located at the Naval Research Laboratory in Washington, D.C.) for evidence of rapidly-rotating neutron stars that could be sources of coherent gravitational radiation. A new data analysis algorithm, which was developed, is described. The algorithm was applied to data from observations of Cyg X-2, Cyg X-3, and 1820-30. Upper limits on pulse fraction were derived and reported

Spectroscopic study of the N159/N160 complex in the Large Magellanic Cloud

We present a spectroscopic study of the N159/N160 massive-star forming region south of 30 Doradus in the Large Magellanic Cloud, classifying a total of 189 stars in the field of the complex. Most of them belong to O and early B spectral classes; we have also found some uncommon and very interesting spectra, including members of the Onfp class, a Be P Cygni star, and some possible multiple systems. Using spectral types as broad indicators of evolutionary stages, we considered the evolutionary status of the region as a whole. We infer that massive stars at different evolutionary stages are present throughout the region, favoring the idea of a common time for the origin of recent star formation in the N159/N160 complex as a whole, while sequential star formation at different rates is probably present in several subregions.Comment: 36 pages, 24 figures (127 spectra mostly OB stars, 4 field images). Published in The Astronomical Journa