Identification and correction of water velocity measurement errors associated with ultrasonic Doppler flow monitoring

Ultrasonic Doppler flow monitoring (UDFM) is used to measure water flow in pipes and channels. However, a lack of scattering particles and signal noise can cause velocity errors, particularly for smaller discharges and surface water (‘clean’) flows. A post-processing methodology is presented that identifies and corrects these errors, maximising the value of existing data. Test criteria are used to identify errors. The error correction procedure defines depth-velocity relationships from cleaned ‘training data’ representing the range of flow conditions (including backed up) and uses these relationships to automatically replace erroneous velocities. UDFM velocity errors have been successfully identified and corrected in example applications. Routine use allows early identification of changes in instrument or site behaviour. The methodology is practical, consistent and updateable. This is a significant advancement on previous methods for correcting velocity errors, improving the applicability of UDFM

Evaluating Cache Coherent Shared Virtual Memory for Heterogeneous Multicore Chips

The trend in industry is towards heterogeneous multicore processors (HMCs), including chips with CPUs and massively-threaded throughput-oriented processors (MTTOPs) such as GPUs. Although current homogeneous chips tightly couple the cores with cache-coherent shared virtual memory (CCSVM), this is not the communication paradigm used by any current HMC. In this paper, we present a CCSVM design for a CPU/MTTOP chip, as well as an extension of the pthreads programming model, called xthreads, for programming this HMC. Our goal is to evaluate the potential performance benefits of tightly coupling heterogeneous cores with CCSVM

An Age Constraint for the Very Low-Mass Stellar/Brown Dwarf Binary 2MASS J03202839-0446358AB

2MASS J03202839-0446358AB is a recently identified, late-type M dwarf/T dwarf spectroscopic binary system for which both the radial velocity orbit for the primary and spectral types for both components have been determined. By combining these measurements with predictions from four different sets of evolutionary models, we determine a minimum age of 2.0+/-0.3 Gyr for this system, corresponding to minimum primary and secondary masses of 0.080 Msun and 0.053 Msun, respectively. We find broad agreement in the inferred age and mass constraints between the evolutionary models, including those that incorporate atmospheric condensate grain opacity; however, we are not able to independently assess their accuracy. The inferred minimum age agrees with the kinematics and absence of magnetic activity in this system, but not the rapid rotation of its primary, further evidence of a breakdown in angular momentum evolution trends amongst the lowest luminosity stars. Assuming a maximum age of 10 Gyr, we constrain the orbital inclination of this system to i >~ 53 degrees. More precise constraints on the orbital inclination and/or component masses of 2MASS J0320-0446AB, through either measurement of the secondary radial velocity orbit (optimally in the 1.2-1.3 micron band) or detection of an eclipse (only 0.3% probability based on geometric constraints), would yield a bounded age estimate for this system, and the opportunity to use it as an empirical test for brown dwarf evolutionary models at late ages.Comment: 8 pages, 2 figures, accepted for publication to Astonomical Journa

A Simple Approach to Project Extreme Old Age Mortality Rates and Value Mortality-Related Financial Instruments

This article shows how mortality models that involve age effects can be fitted to ages beyond the sample range using projections of age effects as replacements for age effects that might not be in the sample. This ‘projected age effect’ approach allows insurers to use age-effect mortality models to obtain valuations of financial instruments such as annuities that depend on projections of extreme old ag

The Rowland Clark (41RR77) Site, Red River County, Texas : Editor\u27s Introduction

The Rowland Clark (41RR77) and Dan Holdeman (41RR11) archaeological sites were excavated in the late 1970s and early 1980s by Gregory Perino of the Museum of Red River in Idabel, Oklahoma. Manuscripts on those investigations were prepared by Perino shortly after the conclusion of the work, but these were never published, remaining instead on file at the Museum of the Red River

A LINKED ANNUAL AND MONTHLY MODEL FOR FORECASTING ALFALFA HAY PRICES

This article develops a model to forecast monthly alfalfa hay prices before the first harvest. This is done by linking an annual model, which forecasts the initial May price, with a system of monthly equations that track the monthly seasonal price pattern, given the forecasted May price.Crop Production/Industries, Demand and Price Analysis,

Fluid mechanics of nodal flow due to embryonic primary cilia

Breaking of left–right symmetry is crucial in vertebrate development. The role of cilia-driven flow has been the subject of many recent publications, but the underlying mechanisms remain controversial. At approximately 8 days post-fertilization, after the establishment of the dorsal–ventral and anterior–posterior axes, a depressed structure is found on the ventral side of mouse embryos, termed the ventral node. Within the node, ‘whirling’ primary cilia, tilted towards the posterior, drive a flow implicated in the initial left–right signalling asymmetry. However, the underlying fluid mechanics have not been fully and correctly explained until recently and accurate characterization is required in determining how the flow triggers the downstream signalling cascades. Using the approximation of resistive force theory, we show how the flow is produced and calculate the optimal configuration to cause maximum flow, showing excellent agreement with in vitro measurements and numerical simulation, and paralleling recent analogue experiments. By calculating numerical solutions of the slender body theory equations, we present time-dependent physically based fluid dynamics simulations of particle pathlines in flows generated by large arrays of beating cilia, showing the far-field radial streamlines predicted by the theory