Theoretical study of the mechanisms of fatigue in photomultipliers, phase 2 Final report

Fatigue testing of photomultipliers with gallium phosphide dynode

Boys\u27 and Girls\u27 Club Work

What is Club Work? It is an organized effort to awaken the interest of boys and girls in agriculture and industrial problems, to induce them to increase the wealth of the community by the production and conservation of grain and meats and vegetables through club activities and to train their hands and minds by practice and instruction in various field and home projects

Fracture clinic redesign reduces the cost of outpatient orthopaedic trauma care

Objectives: “Virtual fracture clinics” have been reported as a safe and effective alternative to the traditional fracture clinic. Robust protocols are used to identify cases that do not require further review, with the remainder triaged to the most appropriate subspecialist at the optimum time for review. The objective of this study was to perform a “top-down” analysis of the cost effectiveness of this virtual fracture clinic pathway. Methods: National Health Service financial returns relating to our institution were examined for the time period 2009 to 2014 which spanned the service redesign. Results: The total staffing costs rose by 4% over the time period (from £1 744 933 to £1 811 301) compared with a national increase of 16%. The total outpatient department rate of attendance fell by 15% compared with a national fall of 5%. Had our local costs increased in line with the national average, an excess expenditure of £212 705 would have been required for staffing costs. Conclusions: The virtual fracture clinic system was associated with less overall use of staff resources in comparison to national cost data. Adoption of this system nationally may have the potential to achieve significant cost savings

Obstetrician-assessed maternal health at pregnancy predicts offspring future health

Background: We aimed to examine the association between obstetrician assessment of maternal physical health at the time of pregnancy and offspring cardiovascular disease risk.<p></p> Methods and Principal Findings: We examined this association in a birth cohort of 11,106 individuals, with 245,000 person years of follow-up. We were concerned that any associations might be explained by residual confounding, particularly by family socioeconomic position. In order to explore this we used multivariable regression models in which we adjusted for a range of indicators of socioeconomic position and we explored the specificity of the association. Specificity of association was explored by examining associations with other health related outcomes. Maternal physical health was associated with cardiovascular disease: adjusted (socioeconomic position, complications of pregnancy, birthweight and childhood growth at mean age 5) hazard ratio comparing those described as having poor or very poor health at the time of pregnancy to those with good or very good health was 1.55 (95%CI: 1.05, 2.28) for coronary heart disease, 1.91 (95%CI: 0.99, 3.67) for stroke and 1.57 (95%CI: 1.13, 2.18) for either coronary heart disease or stroke. However, this association was not specific. There were strong associations for other outcomes that are known to be related to socioeconomic position (3.61 (95%CI: 1.04, 12.55) for lung cancer and 1.28 (95%CI:1.03, 1.58) for unintentional injury), but not for breast cancer (1.10 (95%CI:0.48, 2.53)).<p></p> Conclusions and Significance: These findings demonstrate that a simple assessment of physical health (based on the appearance of eyes, skin, hair and teeth) of mothers at the time of pregnancy is a strong indicator of the future health risk of their offspring for common conditions that are associated with poor socioeconomic position and unhealthy behaviours. They do not support a specific biological link between maternal health across her life course and future risk of cardiovascular disease in her offspring.<p></p&gt

Beach and Vegetation-Line Changes at Galveston Island, Texas: Erosion, Deposition, and Recovery from Hurricane Alicia

On August 18, 1983, Hurricane Alicia crossed the Upper Texas Gulf Coast and caused extensive property damage, especially along West Beach of Galveston Island. Aerial photographs taken before and after Alicia, along with field measurements made during the first post-storm year, provide a basis for determining nearshore changes associated with a major storm and for predicting potential beach recovery. Alicia caused substantial landward retreat of both the shoreline and the vegetation line. Retreat of the vegetation line ranged from 20 to 145 ft and averaged 80 ft. Erosion was generally greatest near the Sea Isle and Bay Harbor subdivisions, where storm processes were most intense; beach erosion generally decreased away from San Luis Pass, which is near the site of storm landfall. Because erosion was so severe, surface elevations were lowered as much as 4.5 ft and many Gulf-front houses were undermined and exposed on the beach after the storm. Alicia eroded several million cubic yards of sand from West Beach. About one-tenth of that sand was deposited on the adjacent barrier flat as a washover terrace. Washover penetration was greatest to the east of the storm's eye and along developed shoreline segments. The remaining eroded beach sand was deposited offshore as shoreface bars or as storm deposits on the inner shelf. The shoreface deposits promoted rapid forebeach accretion during the first post-storm year; at the same time, the backbeach elevation remained about 3 ft lower than before the storm, and the natural post-Alicia vegetation line remained essentially unchanged. Recovery of the vegetation line 1 year after the storm was insignificant mainly because the depth of beach erosion exceeded the depth of root penetration, thus eliminating plants from some areas that were densely vegetated before the storm.Bureau of Economic Geolog

Historical Monitoring of Shoreline Changes in Corpus Christi, Nueces, and Oso Bays

Changes in the position and stability of shorelines in Corpus Christi, Nueces, and Oso Bays since the late 1800s were documented using historical monitoring techniques. This is accomplished by comparing shorelines from topographic charts (dated 1867 to 1882) and aerial photographs (taken in 1930 to 1937 and 1982), measuring the magnitude (distance) of shoreline movement at specific sites, and calculating the rates of change for particular time periods (late 1800s to 1930s, 1930s to 1982, and late 1800s to 1982). Geological interpretations of the maps and photographs are used in conjunction with meteorological data and historical records to explain the important trends revealed in the tabulated shoreline data. Unprotected sediments forming the margins of Corpus Christi, Nueces, and Oso Bays are subjected to natural processes and modified by human activities that together cause shoreline movement. These unstabilized shorelines include high clay bluffs, moderate slopes composed mainly of sand, salt-water marshes, sand and shell beaches, and newly formed areas filled by dredged material. Composition of the shoreline material and orientation of the shoreline with respect to prevailing wind directions and wave fetch largely determine the response and consequent movement of the shoreline. In some areas property owners have attempted to stabilize the shoreline and prevent further movement by building seawalls and bulkheads and using riprap to dissipate wave energy. Factors contributing to shoreline changes include (1) regional and worldwide climate, (2) local changes in relative sea-level position, (3) local alterations in sediment supply, (4) storm frequency and intensity, and (5) human activities. Historical data compiled for these various factors indicate that warming temperatures, rising sea level, decreasing sediment supply, recurring severe storms, and ongoing human activities all favor continued erosion of exposed shorelines.Bureau of Economic Geolog

Coherence of Spin Qubits in Silicon

Given the effectiveness of semiconductor devices for classical computation one is naturally led to consider semiconductor systems for solid state quantum information processing. Semiconductors are particularly suitable where local control of electric fields and charge transport are required. Conventional semiconductor electronics is built upon these capabilities and has demonstrated scaling to large complicated arrays of interconnected devices. However, the requirements for a quantum computer are very different from those for classical computation, and it is not immediately obvious how best to build one in a semiconductor. One possible approach is to use spins as qubits: of nuclei, of electrons, or both in combination. Long qubit coherence times are a prerequisite for quantum computing, and in this paper we will discuss measurements of spin coherence in silicon. The results are encouraging - both electrons bound to donors and the donor nuclei exhibit low decoherence under the right circumstances. Doped silicon thus appears to pass the first test on the road to a quantum computer.Comment: Submitted to J Cond Matter on Nov 15th, 200

Quantum computing with an electron spin ensemble

We propose to encode a register of quantum bits in different collective electron spin wave excitations in a solid medium. Coupling to spins is enabled by locating them in the vicinity of a superconducting transmission line cavity, and making use of their strong collective coupling to the quantized radiation field. The transformation between different spin waves is achieved by applying gradient magnetic fields across the sample, while a Cooper Pair Box, resonant with the cavity field, may be used to carry out one- and two-qubit gate operations.Comment: Several small corrections and modifications. This version is identical to the version published in Phys. Rev. Let

Global Optical Control of a Quantum Spin Chain

Quantum processors which combine the long decoherence times of spin qubits together with fast optical manipulation of excitons have recently been the subject of several proposals. I show here that arbitrary single- and entangling two-qubit gates can be performed in a chain of perpetually coupled spin qubits solely by using laser pulses to excite higher lying states. It is also demonstrated that universal quantum computing is possible even if these pulses are applied {\it globally} to a chain; by employing a repeating pattern of four distinct qubit units the need for individual qubit addressing is removed. Some current experimental qubit systems would lend themselves to implementing this idea.Comment: 5 pages, 3 figure

High Fidelity Single Qubit Operations using Pulsed EPR

Systematic errors in spin rotation operations using simple RF pulses place severe limitations on the usefulness of the pulsed magnetic resonance methods in quantum computing applications. In particular, the fidelity of quantum logic operations performed on electron spin qubits falls well below the threshold for the application of quantum algorithms. Using three independent techniques, we demonstrate the use of composite pulses to improve this fidelity by several orders of magnitude. The observed high-fidelity operations are limited by pulse phase errors, but nevertheless fall within the limits required for the application of quantum error correction.Comment: 4 pages, 3 figures To appear in Phys. Rev. Let