860 research outputs found

    Research Needed on Wood Durability for Residential Structures

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    Effects of drinking-water filtration on Cryptosporidium Seroepidemiology, Scotland

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    Continuous exposure to low levels of Cryptosporidium oocysts is associated with production of protective antibodies. We investigated prevalence of antibodies against the 27-kDa Cryptosporidium oocyst antigen among blood donors in 2 areas of Scotland supplied by drinking water from different sources with different filtration standards: Glasgow (not filtered) and Dundee (filtered). During 2006–2009, seroprevalence and risk factor data were collected; this period includes 2007, when enhanced filtration was introduced to the Glasgow supply. A serologic response to the 27-kDa antigen was found for ≈75% of donors in the 2 cohorts combined. Mixed regression modeling indicated a 32% step-change reduction in seroprevalence of antibodies against Cryptosporidium among persons in the Glasgow area, which was associated with introduction of enhanced filtration treatment. Removal of Cryptosporidium oocysts from water reduces the risk for waterborne exposure, sporadic infections, and outbreaks. Paradoxically, however, oocyst removal might lower immunity and increase the risk for infection from other sources

    Formosan Subterranean Termite Resistance of Borate-Modified Strandboard Manufactured From Southern Wood Species: A Laboratory Trial

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    The behavior of Formosan subterranean termites (FST) toward zinc borate (ZB) and calcium borate (CB)-treated oriented strandboard (OSB) from southern mixed hardwoods and southern yellow pine was examined in laboratory tests. Loading of ZB and CB in OSB provided protection from severe structural damage, but did not completely eliminate termite activity. The level of borate used showed significant effects on weight loss, percent termite mortality, and termite damage rating. Borate types had a significant effect on the sample weight loss and damage rating, but not on termite mortality. Wood species showed no significant effect on the termite resistance. Correlations between weight loss and damage rating and between weight loss and termite mortality for both wood species were fitted well by a decaying exponential function. A three-way regression analysis showed a significant curvilinear relationship among damage rating, weight loss, and termite mortality. Zinc and calcium borate treatment to retention levels greater than 1.0% BAE provided sufficient protection from FST attack. Additional field tests may be needed to determine whether ZB and CB treatments will protect OSB from large-scale attack by FST and if modified OSB panels will be acceptable commercially

    Calling time on Oronsay: revising settlement models around the mesolithic–neolithic transition in Western Scotland, new evidence from Port Lobh, Colonsay

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    For over 120 years, the shell middens of western Scotland and the series of open-air sites on Oronsay have been the focus of debate in European Mesolithic studies. This paper challenges the significance of Oronsay in light of results from the geophysical survey and test-excavation of a new limpet and periwinkle shell midden dated to the late 5th or start of the 4th millennium cal BC at Port Lobh, Colonsay that offers fresh evidence to re-evaluate critically the role of Oronsay and coastal resources in island settlement models ahead of the Mesolithic–Neolithic transition. Test excavations recovered a marine molluscan assemblage dominated by limpet and periwinkle shells together with crab, sea urchin, a fishbone assemblage composed mainly of Gadidae, some identifiable bird and mammal bone, carbonised macroplant remains, and pumice as well as a bipolar lithic assemblage and coarse stone implements. Novel seasonality studies of saithe otolith thin-sections suggest wintertime tidal fishing practices. At least two activity events may be discerned, dating from the late 5th millennium cal BC. The midden could represent a small number of rapidly deposited assemblages or maybe the result of stocastic events within a more extended timeframe. We argue that alternative research questions are needed to advance long-standing debates about seasonal inter island mobility versus island sedentism that look beyond Oronsay to better understand later Mesolithic occupation patterns and the formation and date of Oronsay middens. We propose alternative methodological strategies to aid identification of contemporaneous sites using geophysical techniques and lithic technological signatures

    Time trends in socioeconomic inequalities in cancer mortality: results from a 35 year prospective study in British men.

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    BACKGROUND: Socioeconomic inequalities in cancer mortality in Britain have been shown to be present in the 1990s and early 2000s. Little is known about on-going patterns in such inequalities in cancer mortality. We examined time trends in socioeconomic inequalities in cancer mortality in Britain between 1978 and 2013. METHODS: A socially representative cohort of 7489 British men with data on longest-held occupational social class, followed up for 35 years, in whom 1484 cancer deaths occurred. RESULTS: The hazard ratio for cancer mortality for manual vs. non-manual social classes remained unchanged; among men aged 50-59 years it was 1.62 (95%CI 1.17-2.24) between 1980-1990 and 1.65 (95%CI 1.14-2.40) between 1990-2000. The absolute difference (non-manual minus manual) in probability of surviving death from cancer to 70 years remained at 3% over the follow-up. The consistency of risks over time was similar for both smoking-related and non-smoking related cancer mortality. CONCLUSION: Socioeconomic inequalities in cancer mortality in Britain remain unchanged over the last 35 years and need to be urgently addressed

    High-Efficiency Resonant RF Spin Rotator with Broad Phase Space Acceptance for Pulsed Polarized Cold Neutron Beams

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    We have developed a radio-frequency resonant spin rotator to reverse the neutron polarization in a 9.5 cm x 9.5 cm pulsed cold neutron beam with high efficiency over a broad cold neutron energy range. The effect of the spin reversal by the rotator on the neutron beam phase space is compared qualitatively to RF neutron spin flippers based on adiabatic fast passage. The spin rotator does not change the kinetic energy of the neutrons and leaves the neutron beam phase space unchanged to high precision. We discuss the design of the spin rotator and describe two types of transmission-based neutron spin-flip efficiency measurements where the neutron beam was both polarized and analyzed by optically-polarized 3He neutron spin filters. The efficiency of the spin rotator was measured to be 98.0+/-0.8% on resonance for neutron energies from 3.3 to 18.4 meV over the full phase space of the beam. As an example of the application of this device to an experiment we describe the integration of the RF spin rotator into an apparatus to search for the small parity-violating asymmetry A_gamma in polarized cold neutron capture on para-hydrogen by the NPDGamma collaboration at LANSCE

    Precision Measurement of PArity Violation in Polarized Cold Neutron Capture on the Proton: the NPDGamma Experiment

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    The NPDGamma experiment at the Los Alamos Neutron Science Center (LANSCE) is dedicated to measure with high precision the parity violating asymmetry in the γ\gamma emission after capture of spin polarized cold neutrons in para-hydrogen. The measurement will determine unambiguously the weak pion-nucleon-nucleon (πNN\pi NN) coupling constant {\it fπ1^1_{\pi}}Comment: Proceedings of the PANIC'05 Conference, Santa Fe, NM, USA, October 24-28, 2005, 3 pages, 2 figure
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