A Continuous Non-demolition Measurement of the Cs Clock Transition Pseudo-spin

We demonstrate a weak continuous measurement of the pseudo-spin associated with the clock transition in a sample of Cs atoms. Our scheme uses an optical probe tuned near the D1 transition to measure the sample birefringence, which depends on the z-component of the collective pseudospin. At certain probe frequencies the differential light shift of the clock states vanishes and the measurement is non-perturbing. In dense samples the measurement can be used to squeeze the collective clock pseudo-spin, and has potential to improve the performance of atomic clocks and interferometers.Comment: 4 pages, 4 figures, ReVTeX, modified text in response to referee's comment

Defining the risk of human exposure to Australian bat lyssavirus through potential non-bat animal infection

Human infection with Australian bat lyssavirus (ABLV) was first reported in November 1996, six months after the first identification of the virus in a flying fox in May 1996. Only two human cases of ABLV infection have been described to date, although hundreds of potential human exposures to ABLV have been reported. Current public health guidance considers the risk of transmission of ABLV from a dog or cat to a person is very low. Furthermore, owners are advised that although the animal has a remote possibility of being infected with ABLV, it should be observed closely for at least three months and to report any behavioural changes that occur. The authors present two cases where the behaviour of dogs after potential exposure to ABLV posed significant questions for veterinary and public health authorities

COTS MEMS Flow-Measurement Probes

As an alternative to conventional tubing instrumentation for measuring airflow, designers and technicians at Glenn Research Center have been fabricating packaging components and assembling a set of unique probes that contain commercial off-the-shelf (COTS) microelectromechanical systems (MEMS) sensor chips. MEMS sensor chips offer some compelling advantages over standard macroscopic measurement devices. MEMS sensor technology has matured through mass production and use in the automotive and aircraft industries. At present, MEMS are the devices of choice for sensors in such applications as tire-pressure monitors, altimeters, pneumatic controls, cable leak detectors, and consumer appliances. Compactness, minimality of power demand, rugged construction, and moderate cost all contribute to making MEMS sensors attractive for instrumentation for future research. Conventional macroscopic flow-measurement instrumentation includes tubes buried beneath the aerodynamic surfaces of wind-tunnel models or in wind-tunnel walls. Pressure is introduced at the opening of each such tube. The pressure must then travel along the tube before reaching a transducer that generates an electronic signal. The lengths of such tubes typically range from 20 ft (approx.= 6 m) to hundreds of feet (of the order of 100 m). The propagation of pressure signals in the tubes damps the signals considerably and makes it necessary to delay measurements until after test rigs have reached steady-state operation. In contrast, a MEMS pressure sensor that generates electronic output can take readings continuously under dynamic conditions in nearly real time. In order to use stainless-steel tubing for pressure measurements, it is necessary to clean many tubes, cut them to length, carefully install them, delicately deburr them, and splice them. A cluster of a few hundred 1/16-in.- (approx.=1.6-mm-) diameter tubes (such clusters are common in research testing facilities) can be several inches (of the order of 10 cm) in diameter and could weigh enough that two technicians are needed to handle it. Replacing hard tubing with electronic chips can eliminate much of the bulk. Each sensor would fit on the tip of a 1/16-in. tube with room to spare. The Lucas NovaSensor P592 piezoresistive silicon pressure sensor was chosen for this project because of its cost, availability, and tolerance to extreme ambient conditions. The sensor chip is 1 mm square by 0.6 mm thick (about 0.039 by 0.039 by 0.024 in.) and includes 0.12-mm (approx.=0.005-in.) wire connection tabs. The figure shows a flow-angularity probe that was built by use of three such MEMS chips. It is planned to demonstrate this MEMS probe as an alternative to a standard tube-type "Cobra" probe now used routinely in wind tunnels and aeronautical hardware. This MEMS probe could be translated across a flow field by use of a suitable actuator, so that its accuracy and the shortness of its response time could be exploited to obtain precise dynamic measurements of a sort that cannot be made by use of conventional tubing-based instrumentation

The Ocean Observatories Initiative

Author Posting. © The Oceanography Society, 2018. This article is posted here by permission of The Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 31, no. 1 (2018): 16–35, doi:10.5670/oceanog.2018.105.The Ocean Observatories Initiative (OOI) is an integrated suite of instrumented platforms and discrete instruments that measure physical, chemical, geological, and biological properties from the seafloor to the sea surface. The OOI provides data to address large-scale scientific challenges such as coastal ocean dynamics, climate and ecosystem health, the global carbon cycle, and linkages among seafloor volcanism and life. The OOI Cyberinfrastructure currently serves over 250 terabytes of data from the arrays. These data are freely available to users worldwide, changing the way scientists and the broader community interact with the ocean, and permitting ocean research and inquiry at scales of centimeters to kilometers and seconds to decades.Funding for the OOI is provided by the National Science Foundation through a Cooperative Support Agreement with the Consortium for Ocean Leadership (OCE-1026342)

Guidelines for Developing a Place-Based Unit

Guidelines for developing a place-based ed unit. Here are some preliminary ideas I was able to brainstorm responses to how some of the place-based unit development guidelines could be addressed while creating curriculum about La Sal del Rey

Enigmatic Red Beds Exposed at Point of Rocks, Cimarron National Grassland, Morton County, Kansas: Chronostratigraphic Constraints from Uranium-Lead Dating of Detrital Zircons

Point of Rocks, a high-relief bluff overlooking the Cimarron River valley in Morton County, Kansas, is capped by distinct white beds of Neogene Ogallala Formation calcrete that overlie red beds of shale, siltstone, and sandstone. These unfossiliferous red beds are currently assigned to the Jurassic System; however, their age has long been debated due to a lack of marker beds, index fossils, and nearby correlative outcrops. As a result, geologists over the years have assigned the rocks to systems ranging from the Permian to the Cretaceous. In this study, four stratigraphic sections were measured in the red beds and three bulk samples were collected to determine the uranium-lead age distributions of detrital zircon (DZ) populations. Red-bed strata composed of fissile shale and sandstone are interpreted as alluvial overbank deposits, while dominantly trough cross-bedded and planar-laminated sandstones are interpreted as tidally influenced fluvial deposits. Detrital zircon age peaks can be grouped into at least seven subpopulations with a youngest single zircon age of 263.8 ± 12.1 Ma, a more conservative age of 293.0 ± 6.95 Ma based on the youngest grouping of three grain ages overlapping at 2σ, and a complete absence of Mesozoic age zircons. In addition, copper oxides along partings and fractures suggest that the red beds once hosted copper sulfides, a common constituent of regional Permian-Triassic red beds. The DZ data--in conjunction with the identification of the Permian Day Creek Dolomite marker bed in logs of nearby drilling tests--strongly suggest that the enigmatic red beds cropping out at the base of Point of Rocks should be assigned to the Guadalupian Big Basin Formation, the uppermost Permian unit in Kansas

A Review of the Stratigraphy of the Ogallala Formation and Revision of Neogene (“Tertiary”) Nomenclature in Kansas

The member names for the Ogallala Formation (including the Valentine, Ash Hollow, and Kimball) in Kansas of Zeller (1968) are abandoned. The Ogallala Formation in Kansas includes strata of Miocene and earliest Pliocene age, revising earlier correlation to the Pliocene only (Zeller, 1968). The Kansas Geological Survey is abandoning use of the term "Tertiary," to be replaced by the term "Neogene." International stage boundaries for the Neogene have not been established in Kansas

The effect of sodium species on methanol synthesis and water-gas shift Cu/ZnO catalysts: utilising high purity zincian georgeite

The effect of sodium species on the physical and catalytic properties of Cu/ZnO catalysts derived from zincian georgeite has been investigated. Catalysts prepared with <100 ppm to 2.1 wt% Na+, using a supercritical CO2 antisolvent technique, were characterised and tested for the low temperature water–gas shift reaction and also CO2 hydrogenation to methanol. It was found that zincian georgeite catalyst precursor stability was dependent on the Na+ concentration, with the 2.1 wt% Na+-containing sample uncontrollably ageing to malachite and sodium zinc carbonate. Samples with lower Na+ contents (<100–2500 ppm) remained as the amorphous zincian georgeite phase, which on calcination and reduction resulted in similar CuO/Cu particle sizes and Cu surface areas. The aged 2.1 wt% Na+ containing sample, after calcination and reduction, was found to comprise of larger CuO crystallites and a lower Cu surface area. However, calcination of the high Na+ sample immediately after precipitation (before ageing) resulted in a comparable CuO/Cu particle size to the lower (<100–2500 ppm) Na+ containing samples, but with a lower Cu surface area, which indicates that Na+ species block Cu sites. Activity of the catalysts for the water–gas shift reaction and methanol yields in the methanol synthesis reaction correlated with Na+ content, suggesting that Na+ directly poisons the catalyst. In situ XRD analysis showed that the ZnO crystallite size and consequently Cu crystallite size increased dramatically in the presence of water in a syn-gas reaction mixture, showing that stabilisation of nanocrystalline ZnO is required. Sodium species have a moderate effect on ZnO and Cu crystallite growth rate, with lower Na+ content resulting in slightly reduced rates of growth under reaction conditions