Since Plio-Pleistocene time, southward migration of shortening in the eastern part of the Greater Caucasus into the Kura foreland basin has progressively formed the Kura fold–thrust belt and Alazani piggyback basin, which separates the Kura fold–thrust belt from the Greater Caucasus. Previous work argued for an eastward propagation of the Kura fold–thrust belt, but this hypothesis was based on coarse geological maps and speculative ages for units within the Kura fold–thrust belt. Here we investigate the initiation of deformation within the Gombori range in the western Kura fold–thrust belt and evaluate this eastward propagation hypothesis. Sediments exposed in the Gombori range have a Greater Caucasus source, despite the modern drainage network in the NE Gombori range, which is dominated by NE-flowing rivers. Palaeocurrent analyses of the oldest and youngest syntectonic units indicate a switch happened between ~2.7 Ma and 1 Ma from dominantly SW-directed flow to palaeocurrents more similar to the modern drainage network. A single successful 26Al–10Be burial date indicates the youngest syntectonic sediments are 1.0 ± 1.0 Ma, which, while not a precise age, is consistent with original mapping suggesting these sediments are of Akchagylian–Apsheronian (2.7–0.88 Ma) age. These results, along with recent updated dating of thrust initiation in the eastern Kura fold–thrust belt, suggest that deformation within the Kura fold–thrust belt initiated synchronously or nearly synchronously along-strike. We additionally use topographic analyses to show that the Gombori range continues to be a zone of active deformation.

Since initial applications of strontium isotope human sourcing in the early 1990s, the use of the method has steadily increased in archaeology and in anthropology more broadly. Despite this trend, the collection of necessary baseline environmental data has not been standardized and sometimes does not occur at all. A thorough environmental sampling strategy will ensure that all the variability within a selected region is documented, which is a critical step to improving the accuracy of sourcing studies. Furthermore, shared strontium baseline data collections are needed to improve the intercomparability of datasets and results. This paper provides a case study from a semiarid region in northwestern New Mexico, USA, highlighting the need for a bottom-up approach to baseline data collection (from bedrock to animal) and describes the methods of pre-field planning and collecting, including rationales for what samples to collect for Sr isotope baseline data. The authors hope that this paper will lay a foundation for the implementation and standardization of Sr isotope baseline data collecting, which does not currently exist.

Research uses of human bodies maintained by mechanical ventilation after being declared dead by neurological criteria (“heart-beating cadavers”), were first published in the early 1980s with a renewed interest in research on the newly or nearly dead occurring in about last decade. While this type of research may take many different forms, recent technologic advances in genomic sequencing along with high hopes for genomic medicine, have inspired interest in genomic research with the newly dead. For example, the Genotype-Tissue Expression (GTEx) program through the National Institutes of Health aims to collect large numbers of diverse human tissues with the eventual goal of elucidating the genetic bases of common diseases through a better understanding of the relationship between genetic variation and gene expression.

Multiple 50 mm hybrid Si-on-SiC substrates consisting of thin film [100] Si (1 μm) on bulk semi-insulating [0001] 6H-SiC wafers were fabricated using low-temperature (150°C) wafer bonding and slicing techniques. A set of samples were prepared comparing various thicknesses of SiO2 (60, 120, 190, 240 and 520 nm) as an intermediate bonding layer between the two materials. A variety of test structures such as Van der Pauw structures, linear transfer-length measurement arrays and resistors were fabricated in the Si layers using standard Si processing (such as lithography, B-diffusion, etching and oxidation) in order to characterize the robustness as well as the electrical and thermal properties of the hybrid substrates. Bulk Si and Si-on-insulator (SOI) substrates were used for comparison. We report the Si layers on the hybrid Si-on-SiC substrates to be device-grade in terms of mobility and crystal structure, and that their device-to-device electrical isolation properties are superior to those of bulk Si and comparable to those of SOI. Furthermore, electrical test structures on hybrid Si-on-SiC substrates exhibit vastly superior heat dissipation compared to equivalent devices on bulk Si or SOI. Specifically, the temperature rise can be as much as 102°C lower in resistor devices made on Si-on-SiC (Tj= 191°C) compared to on bulk Si (Tj= 293C) under high-power density operation (67 kW/cm2). We also describe the effects of intermediate oxide thickness on thermal resistance.

Lunar laser ranging (LLR) (Dickey et al., 1994) consists of measuring changes in the round-trip travel time for a laser pulse traveling between a transmitter on the Earth and a reflector on the Moon. The lunar surface reflectors are still operating normally after almost three decades of use. The ranging data exhibit a rich spectrum of change due to many effects.

We briefly review the concept of double star measurement with HST Fine Guidance Sensors (FGS) in the Transfer Function (TF) Scan mode and give results for three calibration binaries observed with FGS3. Agreement among multiple observations indicates an astrometric precision of 1 millisecond of arc (mas) per observation. We compare measured angular separations with ephemeris values from orbits based entirely on speckle observations. This comparison shows that the accuracy of binary-star astrometry with FGS3 in the TF-Scan mode is 1 mas per observation. Multiple observations can be expected to produce relative positions of binary components at sub-millisecond of arc accuracy.

The HST Astrometry Science Team is using the Fine Guidance Sensors (FGS) in the Transfer Function (TF) Scan mode to search for binaries among the faint members of the Hyades cluster. To date (March 1994), nine binaries have been discovered among 24 stars examined. The closest pair (total V=13.5) has a separation of 0.051 arcsec; the faintest (sep=0.287 arcsec) has magnitudes V=15.0 and 16.5; neither object posed a challenge to the capabilities of FGS. For another pair, two observations 152 days apart show a 13 deg change in position angle, indicating rapid orbital motion. One decade should suffice to define the orbit with angular dimensions of sub-millisecond of arc accuracy.

Clearly, this work will soon permit mass determinations for low-luminosity members of the Hyades cluster. Moreover, information on the frequency of binaries will provide insight into the role of duplicity in star formation and in the dynamic evolution of the cluster. To be truly useful, a census of binaries in the Hyades (and other clusters) must ultimately reach cluster members fainter than those currently under investigation, requiring astrometry with sub-millisecond of arc accuracy at near-infrared wavelengths.

Hubble Space Telescope Fine Guidance Sensor 3 can generate sub-milliarcsecond precision parallaxes in eighteen months. We discuss the internal precision and external accuracy of our observations of Proxima Centauri and Barnard's Star. For some classes of targets Hubble Space Telescope will remain the parallax tool of choice for years to come. It can offer 0.5 mas precision. It will remain useful by satisfying urgent needs for quick results, by offering a 13 magnitude dynamic range, and by providing an unparalleled binary dissection capability.

The astrometric capability of the Hubble Space Telescope Planetary Camera (WF/PC1) is investigated, motivated by a study of the internal velocity distribution of globular clusters. The astrometric accuracy of the HST PC will be determined ultimately by 1) the accuracy to which the aberrated images can be ‘centered’, and 2) the accuracy to which the distortions across the PC field can be modeled. A series of overlapping exposures of two clusters, NGC 6752 and M15, are utilized to examine these issues.

We have made use of maximum-likelihood image reconstruction to address the first issue, with good success. Reconstruction improves both the detectability and precision of the image centers. A preliminary exploration of the second issue, that of modeling the distortion across the PC field, is also presented, using positions derived from the multiple overlapping exposures.

The program Pickles was developed as an aid for planning HST observations using the Space Telescope Science Institute's Guide Star Catalogue, which was generated from wide-field Schmidt plates. Pickles reads the catalogue from CD-ROM and then displays a one-degree square field. The HST focal plane apertures can then be displayed singly or in any combination which is at the choice of the observer (Fig. 1). The user can generate an aperture of a different type if need be. The stars can be displayed as open or filled circles with their relative sizes indicating their magnitude. Stars or other objects can be added and saved with the field.

After briefly describing the operation of the Hubble Space Telescope Fine Guidance Sensors (HST–FGS) in the Transfer Function (TF) Scan mode, we discuss the reduction and analysis of scan data affected by HST jitter and Optical Field Angle Distortion (OFAD). We present relative positions and magnitude differences for the components of ADS 11300 = Hu 581 = WDS 18229+1458 derived from TF scans obtained on 17 February 1992. Residuals from a newly revised orbit provide a first indication of the accuracy of HST–FGS observations in the Transfer Function Scan mode.

Some 24 points are made concerning the author’s understanding of the cometary nucleus as developed in this colloquium. Comparisons with an earlier report are noted, and most of the earlier advances in concept are substantiated. The mean density of the Halley nucleus may have been underestimated. The dust/gas ratio apparently needs to be increased by as much as two times, perhaps to unity or higher. The nature of the rotation remains puzzling. CHON grains now appear to be more important sources of gas than thought earlier. A very low temperature at, and subsequent to, the formation of the nucleus continues to receive support, as does a solar-system composition. The 12C/i:3C ratio may, however, be lower than expected.

The Fine Guidance Sensors (FGSs) are the instrument of choice for most astrometric measurements with the Hubble Space Telescope (HST). The observed amount of spherical aberration in the Ritchey Chretien optical system does not affect positional measurements with perfectly aligned FGSs because they are interferometers. The FGSs combine wavefronts from points in the exit pupil with other points which are at the same radial distance from the optical axis. Asymmetric aberrations such as coma and astigmatism do affect the measured positions. The current knowledge of the HST wavefront error, the FGS operation and the implications for milliarcsecond relative astrometry are discussed. It is still planned to use the HST to tie the HIPPARCOS and VLBI Reference Frames together at the few milliarcsecond level.

Various techniques have been used to evaluate and describe coordinate system irregularities. The basic techniques have developed from simple differences to differences in coordinate “bins” to full spherical and cylindrical harmonic treatments. We are undertaking a 15-year program of minor planet observation with the express purpose of finding basic parameters of the adopted fundamental system with respect to a dynamical reference frame. The program is expected to provide a few hundred observations per year of 34 minor planets selected for their distribution of physical and orbital characteristics. The ability of the program to contribute to our knowledge of the rotation of the fundamental system and systematic irregularities within the system will depend on the accuracies of the observations and the distribution of the observations over the orbits and over the celestial sphere. We are considering the use of splines as a method of evaluating systematic corrections to the extant fundamental system. The initial development of the formalism and prospects for evaluation are presented.