Acetylsalicylic acid supplementation improves protein utilization efficiency while vitamin E supplementation reduces markers of the inflammatory response in weaned pigs challenged with enterotoxigenic E. coli

Background: This experiment was conducted to test the hypothesis that vitamin E (Vit E) and acetylsalicylic acid (ASA), a cyclooxygenase-2 (COX-2) inhibitor, will additively reduce the production of the immunosuppressive molecule prostaglandin E2 (PGE2) and hence reduce inflammatory responses in weaner pigs experimentally infected with an enterotoxigenic strain of E. coli. Methods: The experiment was conducted in a research facility with 192 individually-housed male weaner pigs (Landrace × Large White) weighing 6.6 ± 0.04 kg (mean ± SEM). The pigs were experimentally infected with an enterotoxigenic strain of E. coli and were allocated to a 2 × 3 factorial design with the respective factors being without and with 125 ppm ASA and three levels of Vit E supplementation (50, 100 or 200 IU/kg diet, dl-α-tocopheryl acetate). Results: Acetylsalicylic acid supplementation improved average daily gain (P < 0.05) and tended to improve feed:gain ratio (P < 0.10) during the first 14 d after weaning. Acetylsalicylic acid supplementation also improved (P < 0.001) amino acid utilization efficiency (as assessed by plasma urea level) and tended to decrease (P < 0.10) PGE2 production in the liver without affecting small intestinal histology and tight junction protein mRNA expression in the jejunal epithelium. Vitamin E supplementation greater than 100 IU/kg diet sustained both the plasma Vit E concentration (P < 0.001) and plasma haptoglobin content (P < 0.001) after weaning. However, there was no additive effects of the combined supplementation of ASA and Vit E on performance, intestinal barrier function and inflammatory responses of weaned pigs. Conclusions: Although ASA and vitamin E improved amino acid utilization efficiency and reduced acute inflammatory responses, ASA and vitamin E did not additively reduce production of PGE2 and inflammatory responses in weaner pigs experimentally infected with an enterotoxigenic strain of E. coli

Resonant laser tunnelling

We propose an experiment involving a gaussian laser tunneling through a twin barrier dielectric structure. Of particular interest are the conditions upon the incident angle for resonance to occur. We provide some numerical calculations for a particular choice of laser wave length and dielectric refractive index which confirm our expectations.Comment: 15 pages, 6 figure

Evaluating G2G for use in Rapid Response Catchments: Final Report

Flood impacts can be severe for rapid response catchments (RRCs). Providing targeted flood warnings is challenging using existing methodologies and on account of the typical absence of river flow gauging. The Pitt Review of the Summer 2007 floods recognised the need for new alert procedures for RRCs able to exploit the new distributed flood forecasting capability being progressed from research into operations. Work on the G2G (Grid-to-Grid) distributed hydrological model was accelerated into operational practice to support 5-day countrywide flood outlooks, a major recommendation of the Pitt Review. The present study aims to explore the potential of G2G to support more frequent and detailed alerts relevant to flood warning in RRCs. Integral to this study is the use of emerging rainfall forecast products, in deterministic and ensemble form, which allow the lead-time of G2G flow forecasts to be extended and given an uncertainty context. This Report sets down the overall scope of the project, provides an introduction to G2G by way of background and then reports on the outcomes of the R&D study. This includes extensive preparatory work on collating historical datasets to support G2G model assessment, both relating to hydrometry and new rainfall forecast products. A framework is developed for assessing G2G in both simulation-mode and forecast-mode (as a function of lead-time) targeted at the RRC requirement. Relevant to the requirement is the RRC Register of points and areas of interest compiled by the Environment Agency, and the characteristics of RRCs (occurring in isolation or in combination): small catchment area, urban/sub-urban land-cover and steep slopes. The assessment framework is first applied assuming perfect knowledge of rainfall observations for past and future times, so as not to confound the analysis with errors from rainfall forecasts. Variability of performance measures across groups of sites is summarised through box and whisker plots, groups being differentiated on size of catchment area and nature of G2G run (simulation, and with the addition of state updating and flow insertion in turn). Skill scores judge how well the model performs in detecting a flood event exceeding a flow threshold, taken as the median annual flood (as an indicator of bankfull flow exceedance for natural channels) and fractional multipliers of it. The skill scores include POD (Probability of Detection) and FAR (False Alarm Ratio). Performance maps of R2 Efficiency, indicating the variability in the observations accounted for by the model, are used to portray the spatial variability of G2G accuracy across the country. G2G performance in small catchments, relevant to the RRC requirement, is best over South West, North East and North West regions; also median performance appears robust from one year to the next. Larger catchments benefit most in forecast-mode from flow insertion, whilst smaller headwater catchments gain particularly from ARMA (AutoRegressive Moving Average) error-prediction. An assessment is made of using deterministic rainfall forecasts from NWP UKV - the Numerical Weather Prediction UK Variable Resolution form of the Met Office Unified Model - in a full emulation of G2G in real-time, and using foreknowledge of rainfall observations as a reference baseline. Forecast quality can deteriorate strongly beyond 12 hours, especially for smaller catchments, whilst for some locations good performance is maintained even for long lead-times. Diagnostic analysis reveals that the UKV rainfall forecasts have patterns of overestimation in some lowland areas (e.g. over London) and leeward of high elevation areas (e.g. north and south Pennines). Overall performance is better in Scotland although there is evidence of UKV overestimating rainfall near the coast at Edinburgh and Elgin in the north. The assessment framework is extended to include rainfall forecast ensembles and probabilistic flood forecasting, using a combination of case-study and longer-term analyses. Blended Ensemble rainfall forecasts are assessed in two forms: forecasts out to 24 hours updated 4 times a day, and nowcasts out to 7 hours updated every 15 minutes. The 24 hour forecasts generally perform well as input to G2G in the case studies, the G2G flow forecasts typically signalling a flood peak 12 to 18 hours in advance and ahead of any observed response for small catchments. New regional summary map displays of the probability of flow threshold exceedances over a forecast horizon, and for increasing levels of severity, are developed to highlight evolving hotspots of flood risk over time. The first ever continuous assessment of G2G probability flow forecasts is reported using national maps of probabilistic skill scores - Relative Operating Characteristic (ROC) Skill Score and Brier Skill Score (BSS) - to spatially assess their performance. It is noted that the short periods available for assessment - a 7½ month period over England & Wales and 4 ½ months over Scotland - limit the analyses to low return period flow thresholds. Half the median (2-year) flood is used although a regional pooled analysis allows some assessment up to 5-year. The G2G probability forecast assessed is the probability of the chosen flow threshold being exceeded at any time over the forecast horizon (taken to be 24 hours). Comparison of these scores when applied to deterministic and probabilistic forecasts from G2G provides strong evidence of the value of G2G ensemble forecasts as an indicator of flood risk over Britain. Noticeably poorer performance indicated by the BSS across Scotland is in part attributed to the short, summer-dominated assessment period. Operational tools available to FFC and the SFFS for using G2G flow ensembles are reviewed and options for improvement identified drawing on the experience and findings of the study. This leads to identifying some work of an operational nature for consideration in Phase 3 of the project. The report closes with a summary of project achievements grouped thematically, a set of recommendations both of a general nature and specific to FFC and SFFS needs, and finally some proposals for consideration under Phase 3 of the G2G for Rapid Response Catchments project. Some key benefits arising from the project are summarised below. • Evidence has been produced that shows G2G has good skill in providing strategic forecasts for RRCs. The evidence is stratified by catchment type (area, urbanisation, headwater), form of forecast (simulation or forecast mode) and nature of rainfall input (raingauge, deterministic forecast, ensemble forecast). • Strong evidence has been presented on the advantage of using an ensemble rainfall forecast as input to G2G to obtain a probabilistic flood forecast for an RRC, relative to an approach where only a single deterministic rainfall and flood forecast is obtained. This indicates better guidance can be given on forecast flood risk for RRCs, improving the level of service provision for such catchments which are currently not well served. • An improved G2G model configuration, exploiting gauged flows from 912 sites and including new locally calibrated parameters, has been delivered and made operational for the FFC with England & Wales coverage. The benefit is improved operational flood forecast accuracy. For Scotland, an enhanced configuration will be delivered to SFFS in Spring 2014. • Detailed recommendations on how the visual presentation of G2G ensemble results could be improved are set down in this report. When further developed and implemented, these will prove of benefit to the preparation of Flood Guidance Statements issued by FFC and the SFFS across Britain

Scalar Particles in Lattice QCD

We report a project to study scalar particles by lattice QCD simulations. After a brief introduction of the current situation of lattice study of the sigma meson, we describe our numerical simulations of scalar mesons, $\sigma$ and $\kappa$. We observe a low sigma mass, $m_\pi<m_\sigma\le m_\rho$, for which the disconnected diagram plays an important role. For the kappa meson, we obtain higher mass than the experimental value, i.e., $m_\kappa\sim 2m_{K^*}$.Comment: 4 figures, to be published in Proceedings of `International Symposium on Hadron Spectroscopy, Chiral Symmetry and Relativistic Description of Bound Systems' (in a series of KEK proceedings

Quantum lattice fluctuations in a frustrated Heisenberg spin-Peierls chain

As a simple model for spin-Peierls systems we study a frustrated Heisenberg chain coupled to optical phonons. In view of the anorganic spin-Peierls compound CuGeO3 we consider two different mechanisms of spin-phonon coupling. Combining variational concepts in the adiabatic regime and perturbation theory in the anti-adiabatic regime we derive effective spin Hamiltonians which cover the dynamical effect of phonons in an approximate way. Ground-state phase diagrams of these models are determined, and the effect of frustration is discussed. Comparing the properties of the ground state and of low-lying excitations with exact diagonalization data for the full quantum spin phonon models, good agreement is found especially in the anti-adiabatic regime.Comment: 9 pages, 7 figures included, submitted to Phys. Rev.

Ice-rich (periglacial) vs icy (glacial) depressions in the Argyre region, Mars: a proposed cold-climate dichotomy of landforms

On Mars, so-called “scalloped depressions” are widely observed in Utopia Planitia (UP) and Malea Planum (MP). Typically, they are rimless, metres- to decametres-deep, incised sharply, tiered inwardly, polygonised and sometimes pitted. The depressions seemingly incise terrain that is icy and possibly thermokarstic, i.e. produced by the thermal destabilisation of the icy terrain. Agewise, the depressions are thought to be relatively youthful, originating in the Late Amazonian Epoch.Here, we report the presence of similar depressions in the Argyre region (AR) (30–60° S; 290–355° E). More importantly, we separate and differentiate these landforms into two groups: (ice-rich) periglacial depressions (Type-1); and, (icy) glacial depressions (Type-2a-c). This differentiation is presented to the Mars community for the first time.Based on a suite of morphological and geological characteristics synonymous with ice-complexes in the Lena Peninsula (eastern Russia) and the Tuktoyaktuk Coastlands (Northwest Territories, Canada), we propose that the Type-1 depressions are ice-rich periglacial basins that have undergone volatile depletion largely by sublimation and as the result of thermal destabilisation. In keeping with the terms and associated definitions derived of terrestrial periglacial-geomorphology, ice-rich refers to permanently frozen-ground in which ice lenses or segregation ice (collectively referenced as excess ice) have formed.We suggest that the depressions are the product of a multi-step, cold-climate geochronology:(1) Atmospheric precipitation and surface accumulation of an icy mantle during recent high obliquities.(2) Regional or local triple-point conditions and thaw/evaporation of the mantle, either by exogenic forcing, i.e. obliquity-driven rises of aerial and sub-aerial temperatures, or endogenic forcing, i.e. along Argyre impact-related basement structures.(3) Meltwater migration into the regolith, at least to the full depth of the depressions.(4) Freeze-thaw cycling and the formation of excess ice.(5) Sublimation of the excess ice and depression formation as high obliquity dissipates and near-surface ice becomes unstable.The Type-2 depressions exhibit characteristics suggestive of (supra-glacial) dead-ice basins and snow/ice suncups observed in high-alpine landscapes on Earth, e.g. the Swiss Alps and the Himalayas. Like the Type-1 depressions, the Type-2 depressions could be the work of sublimation; however, the latter differ from the former in that they seem to develop within a glacial-like icy mantle that blankets the surface rather than within an ice-rich and periglacially-revised regolith at/near the surface.Interestingly, the Type-2 depressions overlie the Type-1 depressions at some locations. If the periglacial/glacial morphological and stratigraphical dichotomy of depressions is valid, then this points to recent glaciation at some locations within the AR being precursed by at least one episode of periglaciation. This also suggests that periglaciation has a deeper history in the region than has been thought hitherto. Moreover, if the hypothesised differences amongst the Argyre-based depressions are mirrored in Utopia Planitia and Malea Planum, then perhaps this periglacial-glacial dichotomy and its associated geochronology are as relevant to understanding late period landscape-evolution in these two regions as it is in the AR

Clastic Polygonal Networks Around Lyot Crater, Mars: Possible Formation Mechanisms From Morphometric Analysis

Polygonal networks of patterned ground are a common feature in cold-climate environments. They can form through the thermal contraction of ice-cemented sediment (i.e. formed from fractures), or the freezing and thawing of ground ice (i.e. formed by patterns of clasts, or ground deformation). The characteristics of these landforms provide information about environmental conditions. Analogous polygonal forms have been observed on Mars leading to inferences about environmental conditions. We have identified clastic polygonal features located around Lyot crater, Mars (50°N, 30°E). These polygons are unusually large (> 100 m diameter) compared to terrestrial clastic polygons, and contain very large clasts, some of which are up to 15 metres in diameter. The polygons are distributed in a wide arc around the eastern side of Lyot crater, at a consistent distance from the crater rim. Using high-resolution imaging data, we digitised these features to extract morphological information. These data are compared to existing terrestrial and Martian polygon data to look for similarities and differences and to inform hypotheses concerning possible formation mechanisms. Our results show the clastic polygons do not have any morphometric features that indicate they are similar to terrestrial sorted, clastic polygons formed by freeze-thaw processes. They are too large, do not show the expected variation in form with slope, and have clasts that do not scale in size with polygon diameter. However, the clastic networks are similar in network morphology to thermal contraction cracks, and there is a potential direct Martian analogue in a sub-type of thermal contraction polygons located in Utopia Planitia. Based upon our observations, we reject the hypothesis that polygons located around Lyot formed as freeze-thaw polygons and instead an alternative mechanism is put forward: they result from the infilling of earlier thermal contraction cracks by wind-blown material, which then became compressed and/or cemented resulting in a resistant fill. Erosion then leads to preservation of these polygons in positive relief, while later weathering results in the fracturing of the fill material to form angular clasts. These results suggest that there was an extensive area of ice-rich terrain, the extent of which is linked to ejecta from Lyot crater