Doppler Tracking

This study addresses the development of a methodology using the Doppler Effect for high-resolution, short-range tracking of small projectiles and vehicles. Minimal impact on the design of the moving object is achieved by incorporating only a transmitter in it and using ground stations for all other components. This is particularly useful for tracking objects such as sports balls that have configurations and materials that are not conducive to housing onboard instrumentation. The methodology developed here uses four or more receivers to monitor a constant frequency signal emitted by the object. Efficient and accurate schemes for filtering the raw signals, determining the instantaneous frequencies, time synching the frequencies from each receiver, smoothing the synced frequencies, determining the relative velocity and radius of the object and solving the nonlinear system of equations for object position in three dimensions as a function of time are developed and described here

Structural Dissonance in Galaxy Decomposition: The red sequence and evolutionary pathways in the Coma Cluster

The structural and photometric properties of ‘red-and-dead’ early-type galaxies provide vital clues about the evolutionary pathway which lead to their formation. Here, I use deep Canada-France-Hawaii Telescope image data to explore the multi-component internal structures of red sequence galaxies in the Coma cluster, with a particular focus on disk-dominated early-type galaxies (i.e. S0s). Galaxies are investigated across a wide range of uminosities (−17 > M_g > −22) and cluster-centric radii (0 < r_cluster < 1.3 r_200). I present the 2D structural decomposition of u, g, i imaging via GALFIT. Rigorous filtering is applied to ensure that the measured best-fit models are the most meaningful descriptions of their galaxy’s underlying stellar structures. A sample of Coma cluster members (N = 200) was identified as well described by an ‘archetypal’ S0 structure (central bulge + outer disk). Internal bulge and/or disk colour gradients were implemented by allowing component sizes to vary between bands. Such gradients are required for 30% of archetypal S0 galaxies. Bulges are characterised by n ~2 profiles with half-light radii, R_e ~1 kpc, remaining consistent in size for all but the brightest galaxies (M_g < −20.5). S0 disks are brighter (at fixed size, or smaller at fixed luminosity) than those of star-forming spirals. Similar colour-magnitude relations are found for both bulges and disks. The global red sequence for S0s in Coma hence results from a combination of both component trends. The average bulge − disk colour difference is 0.09 ± 0.01 mag in g − i, and 0.16 ± 0.01 mag in u − g. Using simple stellar population models, bulges are either ~2-3× older, or ~2× more metal-rich than disks. The trend towards bluer global S0 colours observed further from Coma’s core is driven by a significant correlation of disk colour with cluster-centric radius. An equivalent trend is detected in bulge colours at a marginal significance level. An environment-mediated mechanism of disk fading is favoured as the dominant factor in S0 formation. The decomposition analysis was then extended to encompass a wider range of structural models. This revealed a large sample of reliably-fit, symmetric multi-component galaxies in Coma (N = 478). 42±3% of Coma cluster galaxies (N = 201) are best described by a 3(+) component structure. In addition, 11% of galaxies (N = 52) feature a break in their outer profiles, indicating truncated or anti-truncated disks. Beyond the break radius, truncated disks are consistent in structure with untruncated disks, disfavouring a formation mechanism via physical truncation of exponential disks. The sizes/luminosities of bulges in antitruncated galaxies correlate strongly with galaxy luminosity, indicating a bulge-enhancement formation mechanism for anti-truncated disks. Both types of broken disk are found overwhelmingly (> 70%) in barred galaxies, suggesting that galaxy bar play an important role in formation of such structures. The wide variety of galaxy structures detected in Coma highlights the naivete of the simple ‘bulge + disk’ or ‘single spheroid’ morphological paradigm for early-type galaxies

Palaeoenvironmental research at Hawelti–Melazo (Tigray, northern Ethiopia) – insights from sedimentological and geomorphological analyses

The sites of Hawelti–Melazo in the Tigray region of the northern Ethiopian Highlands is an archaeological hotspot related to the D'mt kingdom (ca. 800–400 BCE). The existence of several monumental buildings, which have been excavated since the 1950s, underline the importance of this area in the Ethio-Sabaean period. We investigated the geomorphological and geological characteristics of the site and its surroundings and carried out sedimentological analyses, as well as direct (luminescence) and indirect (radiocarbon) sediment dating, to reconstruct the palaeoenvironmental conditions, which we integrated into the wider context of Tigray. Luminescence dating of feldspar grains from the May Agazin catchment indicate enhanced fluvial activity in the late Pleistocene, likely connected to the re-occurring monsoon after the Last Glacial Maximum (LGM). The abundance of trap basalt on the Melazo plateau, which provides the basis for the development of fertile soils, and the presumably higher groundwater level during the Ethio-Sabaean Period, provided favourable settlement conditions. The peninsula-like shape of the Melazo plateau was easily accessible only from the east and northeast, while relatively steep scarps enclose the other edges of the plateau. This adds a possible natural protective function to this site

Myriad Stands Alone

Myriad took no prisoners on its way to the top of the molecular diagnostics field. That strategy is unlikely to endure.Ope

Stem Cell Patents After the America Invents Act

Under the newly passed Leahy-Smith America Invents Act (AIA), the U.S. Patent and Trademark Office may hear new challenges to stem cell patents. Here, we explore how the new law affects challenges to stem cell patents, focusing on two recent cases, and discuss the future of stem cell patent disputes.Ope

SuperCam, a 64-pixel heterodyne imaging array for the 870 micron atmospheric window

We report on the development of SuperCam, a 64 pixel, superheterodyne camera designed for operation in the astrophysically important 870 micron atmospheric window. SuperCam will be used to answer fundamental questions about the physics and chemistry of molecular clouds in the Galaxy and their direct relation to star and planet formation. The advent of such a system will provide an order of magnitude increase in mapping speed over what is now available and revolutionize how observational astronomy is performed in this important wavelength regime. Unlike the situation with bolometric detectors, heterodyne receiver systems are coherent, retaining information about both the amplitude and phase of the incident photon stream. From this information a high resolution spectrum of the incident light can be obtained without multiplexing. SuperCam will be constructed by stacking eight, 1x8 rows of fixed tuned, SIS mixers. The IF output of each mixer will be connected to a low-noise, broadband MMIC amplifier integrated into the mixer block. The instantaneous IF bandwidth of each pixel will be ~2 GHz, with a center frequency of 5 GHz. A spectrum of the central 500 MHz of each IF band will be provided by the array spectrometer. Local oscillator power is provided by a frequency multiplier whose output is divided between the pixels by using a matrix of waveguide power dividers. The mixer array will be cooled to 4K by a closed-cycle refrigeration system. SuperCam will reside at the Cassegrain focus of the 10m Heinrich Hertz telescope (HHT). A prototype single row of the array will be tested on the HHT in 2006, with the first engineering run of the full array in late 2007. The array is designed and constructed so that it may be readily scaled to higher frequencies.Comment: 12 pages, 14 figures, to be published in the Proceedings of SPIE Vol. 6275, "Astronomical Telescopes and Instrumentation, Millimeter and Submillimeter Detectors and Instrumentation for Astronomy III

High-efficiency endovascular gene delivery via therapeutic ultrasound

AbstractOBJECTIVESWe studied enhancement of local gene delivery to the arterial wall by using an endovascular catheter ultrasound (US).BACKGROUNDUltrasound exposure is standard for enhancement of in vitro gene delivery. We postulate that in vivo endovascular applications can be safely developed.METHODSWe used a rabbit model of arterial mechanical overdilation injury. After arterial overdilation, US catheters were introduced in bilateral rabbit femoral arteries and perfused with plasmid- or adenovirus-expressing blue fluorescent protein (BFP) or phosphate buffered saline. One side received endovascular US (2 MHz, 50 W/cm2, 16 min), and the contralateral artery did not.RESULTSRelative to controls, US exposure enhanced BFP expression measured via fluorescence 12-fold for plasmid (1,502.1 ± 927.3 vs. 18,053.9 ± 11,612 μm2, p < 0.05) and 19-fold for adenovirus (877.1 ± 577.7 vs. 17,213.15 ± 3,892 μm2, p < 0.05) while increasing cell death for the adenovirus group only (26 ± 5.78% vs. 13 ± 2.55%, p < 0.012).CONCLUSIONSEndovascular US enhanced vascular gene delivery and increased the efficiency of nonviral platforms to levels previously attained only by adenoviral strategies