Inertial measurement unit pre-processors and post-flight STS-1 comparisons

The flight results show that the relative tri-redundant Inertial Measurement Unit IMU performance throughout the entire entry flight was within the expected accuracy. Comparisons are presented which show differences in the accumulated sensed velocity changes as measured by the tri-redundant IMUs (in Mean Equator and Equinox of 1950.0), differences in the equivalent inertial Euler angles as measured with respect to the M50 system, and finally, preliminary instrument calibrations determined relative to the ensemble average measurement set. Also, differences in the derived body axes rates and accelerations are presented. Because of the excellent performance of the IMUs during the STS-1 entry, the selection as to which particular IMU would best serve as the dynamic data source for entry reconstruction is arbitrary

GRAPE - A Balloon-Borne Gamma-Ray Polarimeter Experiment

This paper reviews the development status of GRAPE (the Gamma-Ray Polarimeter Experiment), a hard X-ray Compton Polarimeter. The purpose of GRAPE is to measure the polarization of hard X-rays in the 50-300 keV energy range. We are particularly interested in X-rays that are emitted from solar flares and gamma-ray bursts (GRBs), although GRAPE could also be employed in the study of other astrophysical sources. Accurately measuring the polarization of the emitted radiation will lead to a better understating of both emission mechanisms and source geometries. The GRAPE design consists of an array of plastic scintillators surrounding a central high-Z crystal scintillator. The azimuthal distribution of photon scatters from the plastic array into the central calorimeter provides a measure of the polarization fraction and polarization angle of the incident radiation. The design of the detector provides sensitivity over a large field-of-view (>pi steradian). The design facilitates the fabrication of large area arrays with minimal deadspace. This paper presents the latest design concept and the most recent results from laboratory tests of a GRAPE science model.Comment: 6 pages; paper presented at the FRASCATI Workshop 2005 on Multifrequency Behaviour of High Energy Cosmic Sources; submitted to Chinese Journal of Astronomy and Astrophysic

The radio luminosity distribution of pulsars in 47 Tucanae

We have used the Australia Telescope Compact Array to seek the integrated radio flux from all the pulsars in the core of the globular cluster 47 Tucanae. We have detected an extended region of radio emission and have calibrated its flux against the flux distribution of the known pulsars in the cluster. We find the total 20-cm radio flux from the cluster's pulsars to be S = 2.0 +/- 0.3 mJy. This implies the lower limit to the radio luminosity distribution to be L_1400 = 0.4 mJy kpc^2 and the size of the observable pulsar population to be N < 30.Comment: 7 pages, 4 figures, MNRAS in pres

The 2000 Periastron Passage of PSR B1259-63

We report here on a sequence of 28 observations of the binary pulsar system PSR B1259-63/SS2883 at four radio frequencies made with the Australia Telescope Compact Array around the time of the 2000 periastron passage. Observations made on 2000 Sep 1 show that the pulsar's apparent rotation measure (RM) reached a maximum of $-14800 \pm 1800$ rad m$^{-2}$, some 700 times the value measured away from periastron, and is the largest astrophysical RM measured. This value, combined with the dispersion measure implies a magnetic field in the Be star's wind of 6 mG. We find that the light curve of the unpulsed emission is similar to that obtained during the 1997 periastron but that differences in detail imply that the emission disc of the Be star is thicker and/or of higher density. The behaviour of the light curve at late times is best modelled by the adiabatic expansion of a synchrotron bubble formed in the pulsar/disc interaction. The expansion rate of the bubble $\sim 12$ km s$^{-1}$ is surprisingly low but the derived magnetic field of 1.6 G close to that expected.Comment: 8 pages, 6 figures, 3 tables, LaTeX (mn.sty). Accepted for publication in the Monthly Notices of the Royal Astronomical Society. Also available at http://astronomy.swin.edu.au/staff/tconnors/publications.htm

On-Farm Forest Income in the United States, 2003–2012: Thoughts for Extension Programming

Forest-based production on U.S. farms totaled $653.2 million in 2012, admittedly a small portion of total farm wealth. However, despite the effects of the recent economic downturn, on-farm forest product revenues still approached the gate value of North Carolina timber in 2012, which was$730.6 million. Providing the research-based information, technology transfer, and educational programs farmers need to manage trees to generate income while preserving the ecosystem in a manner that is socially acceptable requires a multidimensional approach by Extension specialists working across disciplines. Two examples of multidimensional approaches, one centered on audience segmentation for targeted outreach and the other on forest economic development, are proposed and discussed

Hard X‐ray polarimetry of solar flares with BATSE

We describe a technique for measuring the polarization of hard X‐rays from solar flares based on the angular distribution of that portion of the flux which is scattered off the top of the Earth’s atmosphere. The scattering cross section depends not only on the scatter angle itself, but on the orientation of the scatter angle with respect to the incident polarization vector. Consequently, the distribution of the observed albedo flux will depend on the direction and the polarization properties (i.e., the level of polarization and polarization angle) of the source. Since the albedo component can represent a relatively large fraction (up to 40%) of the direct source flux, there will generally be sufficient signal for making such a measurement. The sensitivity of this approach is therefore dictated by the effective area and the ability of a detector system to ‘image’ the albedo flux. The 4π coverage of the BATSE detectors on the Compton Gamma‐RayObservatory provides an opportunity to measure both the direct and the albedo flux from a given solar flare event. Although the BATSE design (with its large field‐of‐view for each detector) is not optimized for albedo polarimetry, we have nonetheless investigated the feasibility of this technique using BATSE data

Environmental modeling and recognition for an autonomous land vehicle

An architecture for object modeling and recognition for an autonomous land vehicle is presented. Examples of objects of interest include terrain features, fields, roads, horizon features, trees, etc. The architecture is organized around a set of data bases for generic object models and perceptual structures, temporary memory for the instantiation of object and relational hypotheses, and a long term memory for storing stable hypotheses that are affixed to the terrain representation. Multiple inference processes operate over these databases. Researchers describe these particular components: the perceptual structure database, the grouping processes that operate over this, schemas, and the long term terrain database. A processing example that matches predictions from the long term terrain model to imagery, extracts significant perceptual structures for consideration as potential landmarks, and extracts a relational structure to update the long term terrain database is given

The design of a gamma‐ray burst polarimeter

The study of the polarization properties of the gamma‐ray bursts is the one remaining unexplored avenue of research which may help to answer some of the fundamental problems regarding the nature of these mysterious objects. We have designed an instrument to measure linear polarization in cosmic gamma‐ray bursts at energies ≳50 keV. Here we describe the design of this instrument, which we call the Gamma‐ray Burst Polarimeter Experiment (GRAPE)

Using BATSE to measure gamma-ray burst polarization

We describe a technique for measuring the polarization of hard x-rays from γ-ray bursts based on the angular distribution of that portion of the flux which is scattered off the top of the Earth’s atmosphere. The scattering cross section depends not only on the scatter angle itself, but on the orientation of the scatter angle with respect to the incident polarization vector. Consequently, the distribution of the observed albedo flux will depend on the direction and the polarization properties (i.e., the level of polarization and polarization angle) of the source. Although the BATSE design (with its large field-of-view for each detector) is not optimized for albedo polarimetry, we have nonetheless investigated the feasibility of this technique using BATSE data

Effect of Concomitant 3-Hydroxy-3-Methyl-Glutaryl-CoA Reductase Inhibitor Therapy on Creatine Phosphokinase Levels and Mortality Among Patients Receiving Daptomycin: Retrospective Cohort Study.

IntroductionThe prescribing information for daptomycin recommends discontinuing statin therapy during receipt of daptomycin. The literature supporting this recommendation is sparse. The objectives of this study were to examine the impact of 3-hydroxy-3-methyl-glutaryl-CoA (HMG-CoA) reductase inhibitors (statins) on creatine phosphokinase (CPK) elevations and mortality among patients receiving daptomycin therapy.MethodsA retrospective cohort study was performed among daptomycin recipients in the Upstate New York Veterans' Healthcare Administration from September 15, 2003 to July 1, 2013. Inclusion criteria were: (1) daptomycin for ≥48 h, (2) availability of baseline CPK value and (3) &gt;1 CPK level measurement taken while on therapy. The following were extracted from medical records: demographics, comorbidities, laboratory data, medication history (daptomycin, statins and concomitant drugs known to increase CPK), Acute Physiology and Chronic Health Evaluation (APACHE)-II score and vital status at 30 days. The exposure of interest was use of statins. The primary outcome was CPK elevation defined as a CPK value ≥3 times the upper limit of normal (ULN) if baseline CPK was normal, and ≥5 times ULN if baseline CPK was elevated. The secondary outcome was death within 30 days of commencing daptomycin.ResultsA total of 233 patients were included in this analysis. Among these patients, 53 received concomitant statin therapy. Most baseline clinical characteristics were similar between statin recipients and non-recipients. Five (2.1%) patients experienced a CPK elevation; 3/53 (5.7%) were statin recipients and 2/180 (1.1%) received daptomycin alone (p = 0.08). All patients with CPK elevations had normal baseline CPK values. No effect modification was observed by use of other concomitant medications known to increase CPK values. Death was observed more frequently among statin non-recipients (17.2%) than recipients (9.4%).ConclusionsAmong patients receiving daptomycin, no significant difference was observed in frequency of CPK elevation between statin recipients and non-recipients