The frequency dependence of normal pulsar radio emission is typically observed to be a power law, with some indications of a flattening or turnover at low frequencies (≲ 100 MHz). The spectrum of the Crab pulsar’s giant pulse emission has not been examined as closely. We conducted simultaneous wideband observations of the Crab pulsar, with the Parkes radio telescope and the Murchison Widefield Array, to study the spectral behaviour of its giant pulses. Our analysis shows that the mean spectral index of Crab giant pulses flattens at low frequencies, from −2.6 ± 0.5 between the Parkes bands, to −0.7 ± 1.4 between the lowest MWA subbands.

At several times during the Quaternary, a major eastward-flowing outlet glacier of the former Patagonian Ice Sheet occupied the Lago San Martin Valley in Argentina (49°S, 72°W). We present a glacial chronology for the valley based on geomorphological mapping and cosmogenic nuclide (10 Be) exposure ages (n = 10) of boulders on moraines and lake shorelines. There are five prominent moraine belts in the Lago San Martin Valley, associated with extensive sandar (glaciofluvial outwash plains) and former lake shorelines. Cosmogenic nuclide exposure ages for boulders on these moraines indicate that they formed at 14.3 ± 1.7 ka, 22.4 ± 2.3 ka, 34.4 ± 3.4 ka to 37.6 ± 3.4 ka (and possibly 60 ± 3.5 ka), and 99 ± 11 ka (1σ). These dated glacier advances differ from published chronologies from the Lago San Martin Valley based on 14C age determinations from organic sediments and molluscs in meltwater channels directly in front of moraines or in kettleholes within end moraine ridges. The moraine boulder ages also point to possible pre-LGM glacial advances during the last glacial cycle and a key observation from our data is that the LGM glaciers were probably less extensive in the Lago San Martin Valley than previously thought.

We explore some aspects of the optimization of amorphous semiconductors as well as low- and high-dielectric-constant (low-/high-k) materials viewed purely from the perspective of percolation and topological constraint theories. We specifically illustrate how percolation, constraint theory, and mean network coordination, 〈r〉, play underlying roles in determining the electrical and mechanical properties of amorphous semiconducting and dielectric materials as well as interfaces that are important for modern micro-/nanoelectronic devices.

Experiments on the National Ignition Facility show that multi-dimensional effects currently dominate the implosion performance. Low mode implosion symmetry and hydrodynamic instabilities seeded by capsule mounting features appear to be two key limiting factors for implosion performance. One reason these factors have a large impact on the performance of inertial confinement fusion implosions is the high convergence required to achieve high fusion gains. To tackle these problems, a predictable implosion platform is needed meaning experiments must trade-off high gain for performance. LANL has adopted three main approaches to develop a one-dimensional (1D) implosion platform where 1D means measured yield over the 1D clean calculation. A high adiabat, low convergence platform is being developed using beryllium capsules enabling larger case-to-capsule ratios to improve symmetry. The second approach is liquid fuel layers using wetted foam targets. With liquid fuel layers, the implosion convergence can be controlled via the initial vapor pressure set by the target fielding temperature. The last method is double shell targets. For double shells, the smaller inner shell houses the DT fuel and the convergence of this cavity is relatively small compared to hot spot ignition. However, double shell targets have a different set of trade-off versus advantages. Details for each of these approaches are described.

Infection surveillance definitions for long-term care facilities (ie, the McGeer Criteria) have not been updated since 1991. An expert consensus panel modified these definitions on the basis of a structured review of the literature. Significant changes were made to the criteria defining urinary tract and respiratory tract infections. New definitions were added for norovirus gastroenteritis and Clostridum difficile infections.

Infect Control Hosp Epidemiol 2012;33(10):965-977

PLATO is a fully-robotic observatory designed for operation inAntarctica. It generates its own electricity (about 1 kW), heat(sufficient to keep two 10-foot shipping containers comfortably above0°C when the outside temperature is at -70°C), andconnects to the internet using the Iridium satellite system (providing~30 MB/day of data transfer). Following a successful first year ofoperation at Dome A during 2008, PLATO was upgraded withnew instruments for 2009.

In January 2005, members of a Chinese expedition team were the firsthumans to visit Dome A on the Antarctic plateau, a sitepredicted to be one of the very best astronomical sites on earth.
In 2006, the Chinese Center for Antarctic Astronomy (CCAA) was foundedto promote the development of astronomy in Antarctica, especially atDome A. CCAA has since taken part in two traverses to Dome A, organizedby the Polar Research Institute of China (PRIC), in the australsummers of 2007/2008 and 2008/2009. These traverses resulted in theinstallation of many site-testing and science instruments, supportedby the PLATO observatory. The Chinese Small Telescope ARray (CSTAR)has produced excellent results from Dome A.
Our future plans include further site-testing work, and the followingfull-scale science instruments: three 0.5-m Antarctic SchmidtTelescopes (AST3), and a proposed 4-m telescope for wide-fieldinfrared high spatial-resolution surveys. The first AST3 telescope isunder construction and is scheduled for installation in 2011.

PLATO is a 6 tonne completely self-contained robotic observatory that provides its own heat, electricity, and satellite communications. It was deployed to Dome A in Antarctica in January 2008 by the Chinese expedition team, and is now in its second year of operation. PLATO is operating four 14.5cm optical telescopes with 1k × 1k CCDs, a wide-field sky camera with a 2k × 2k CCD and Sloan g, r, i filters, a fibre-fed spectrograph to measure the UV to near-IR sky spectrum, a 0.2m terahertz telescope, two sonic radars giving 1m resolution data on the boundary layer to a height of 180m, a 15m tower, meteorological sensors, and 8 web cameras. Beginning in 2010/11 PLATO will be upgraded to support a Multi Aperture Scintillation Sensor and three AST3 0.5m schmidt telescopes, with 10k × 10 CCDs and 100TB/annum data requirements.

Rates of intake of herbage and grazing time of beef cattle are essential components of simulation models of grassland agroecosystems. We studied the effects of herbage allowance on rates of intake and ingestive behaviour of twelve 2-year-old Angus heifers (Bos taurus)(364 ± 12 kg) grazing pastures of tall fescue (Festuca arundinacea Schreb.). A balanced change-over design and a novel tethering technique were used to estimate direct, residual and permanent effects of three herbage allowances on intake per bite, rate of biting and rate of intake. Herbage dry matter (D.M.) allowances, which were established by varying tether lengths, were 5, 9 and 13 kg (1·4, 2·5 and 3·6 kg/100 kg of live weight) and made available in circular plots of 15, 27 and 38 m2, respectively, for a single measured 2 h grazing session each day. Heifers grazing Kenhy tall fescue swards, composed of vegetative tillers and free from the endophyte Acremonium coenophialum, with herbage D.M. masses (> 5 cm) of 2000 kg/ha and D.M. allowances of 9 and 13 kg/2 h per heifer, ingested D.M. at 1·9 kg/h by taking bites averaging 800 mg D.M. at 38 bites/min. Allowances of 5 kg/2 h per heifer slowed the rate of intake to 1·3 kg/h by limiting D.M. intake per bite to 654 mg and biting rate to 35/min. Rate of D.M. intake of cattle grazing vegetative temperate grass swards appears to be ca. 0.5% of live weight per hour when allowance and availability of herbage are not limiting.