Nucleon excited states on the lattice

We study the pion-nucleon system in s-wave in the framework of lattice QCD in order to gain new information on the nucleon excited states. We perform simulations for $n_f =2$ mass degenerate light quarks at a pion mass of 266 MeV. The results show that including the two-particle states drastically changes the energy levels. The variational analysis and the distillation approach play an important role in the extraction of the energy levels. The phase shift analysis allows to extract information on the resonance nature of the observed states.Comment: 6 pages, 2 figures, talk presented at Excited QCD 2013, Bjelasnica Mountain, Sarajev

Effects of electron coupling to intra- and inter-molecular vibrational modes on the transport properties of single crystal organic semiconductors

Electron coupling to intra- and inter-molecular vibrational modes is investigated in models appropriate to single crystal organic semiconductors, such as oligoacenes. Focus is on spectral and transport properties of these systems beyond perturbative approaches. The interplay between different couplings strongly affects the temperature band renormalization that is the result of a subtle equilibrium between opposite tendencies: band narrowing due to interaction with local modes, band widening due to electron coupling to non local modes. The model provides an accurate description of the mobility as function of temperature: indeed, it has the correct order of magnitude, at low temperatures, it scales as a power-law $T^{-\delta}$ with the exponent $\delta$ larger than unity, and, at high temperatures, shows an hopping behavior with a small activation energy.Comment: 3 Figures, Submitte

Effect of phospholipids and bile acids on cholesterol nucleation time and vesicular/micellar cholesterol in gallbladder bile of patients with cholesterol stones

Supersaturation and rapid nucleation of cholesterol in bile are of key importance in the pathogenesis of cholesterol gallstones. While the effects of bile acids and phospholipids on cholesterol saturation of bile have been extensively studied, their influence on the cholesterol nucleation time has not been compared. We, therefore, investigated whether increases of bile acid or phospholipid concentrations in bile by in vitro supplementation affect the cholesterol nucleation time. Bile samples were obtained at surgery from patients with cholesterol gallstones. Prior to the nucleation assay the bile samples were divided into 0.5-ml aliquots and supplemented with 1.25, 2.5, 5.0, and 10.0 mumol/ml of different phosphatidylcholines (PC-dimyristoyl, PC- dipalmitoyl, PC-distearoyl, and extracted biliary PCs) or with 5.0, 10.0, and 20.0 mumol/ml of bile acids (glycine or taurine conjugates of cholic acid, deoxycholic acid, or chenodeoxycholic acid). The increase of phosphatidylcholine or bile acid concentration decreased the mean cholesterol saturation index to a similar extent (PC: 0.1-0.3; BA: 0.1- 0.2). Supplementations of bile with increasing amounts of synthetic or biliary PCs caused a marked prolongation of the nucleation time in bile from 1.5 +/- 0.2 up to > or = 21 days or 2.5 +/- 0.7 up to > or = 21 days. Concurrently, biliary cholesterol was shifted from vesicles to mixed micelles and the cholesterol/phospholipid ratio of the remaining vesicles was progressively lowered. In contrast, the addition of bile acids to gallbladder bile did not affect the cholesterol nucleation time (2.2 +/- 0.3 days), the percentage of vesicular cholesterol, or the cholesterol/phospholipid ratio of vesicles and micelles

Photon-Photon Collisions with SuperChic

The SuperChic Monte Carlo generator provides a common platform for QCD-mediated, photoproduction and photon-induced Central Exclusive Production (CEP), with a fully differential treatment of soft survival effects. In these proceedings we summarise the processes generated, before discussing in more detail those due to photon-photon collisions, paying special attention to the correct treatment of the survival factor. We briefly consider the light-by-light scattering process as an example, before discussing planned extensions and refinements for the generator.Comment: 6 pages, 2 figures. Submitted to proceedings of the PHOTON 2017 conferenc

Horticulture in the UK: potential for meeting dietary guideline demands

Executive Summary Public health analysis suggests that many lives can be saved if the UK population actually followed dietary guidelines on fruit and vegetable daily intake. The Government’s Eatwell Plate suggests that more than a third of UK daily diets should comprise fruit and vegetables and yet currently less than a quarter of diets are taken from this source. A UK debate on the status of the horticultural industry and its potential to meet a recommended increase in consumption is long overdue. This paper, largely based on secondary sources of data, presents current national levels of fruit and vegetable production and consumption. It outlines the origins of what horticultural produce is consumed here and the potential for meeting demand should diets adapt to those suggested by government guidelines. The Briefing provides a summary of key facts on UK horticulture based on information that is publicly available. An FRC seminar is planned to take account of non-documented industry views in order to complete or correct the picture presented here but our current objective is to outline the situation as it appears from published data: • There has been a big decline in area given to horticultural production. From 1985 to 2014, there has been a decline of 27% for fruit and vegetables combined. The area growing vegetables has declined by 26% and the area growing fruit by 35%. • Fruit and vegetables are by far the greatest source of imports in the UK food system. The trade gap in horticulture has risen to £7.8 billion a year, about 37% of the UK’s total food trade gap of £21 billion in 2014. Although some growers have extensive growing operations in Southern Europe and further afield, this makes sense for them as commercial enterprises but still does not resolve the serious lack of UK horticultural output. This is important to meet the 21st century challenge of increasing production for health everywhere and to ensure that rich consumer societies do not excessively distort international trade for their purposes. • Some imports (e.g. pineapples, avocados) could not be grown in the UK (or not yet) but others which could be UK grown (e.g. brassicas, mushrooms, lettuce) have seen massive drops in production. • The proportion of the adult population (over 16 years) in the UK consuming five or more portions of fruit and vegetables per day stood at only 26% in 2013. • Only 16% of children achieved an intake of 5-a-day or more in 2013. • The Consumer Price Index for food items as a whole has shown a significant increase of 35% in 2007-2013. Within this, the price of vegetables has increased by 27% and fresh fruit by 26%, less than the average for the food sector as a whole. • Horticulture is unevenly distributed across the country, partly for climatic reasons, but areas that used to have sizeable sectors (e.g. the South West) have seen a heavy decline. A ‘re-boot’ of regional strategies is overdue to incorporate a review of planning and financial regulations and to rebuild bioregional resilience where appropriate. • Land used for horticulture is highly productive. Only 3.5% of UK croppable land is down to horticulture, yet producing £3.7 billion worth of produce. For every one hectare of land under fruit and vegetables, 4.5 hectares are used for wheat for animal feed- with the inevitably slower and less efficient energy conversion rates. • Horticultural wages for seasonal workers are low, not helped by the abolition of the Agricultural Wages Board. Horticulture occupies only 2% of the farmed area in England yet employs 12% of the agricultural labour force and at least 35% of the UK’s casual farm labour force. The Briefing makes a series of recommendations: • The Government (DEFRA) forthcoming 25 year Food Strategy should apply a ‘health lens’ to its proposed focus on ‘Brand Britain’ • Government, growers, land use specialists, industry and regional bodies should begin to plan the infrastructure needed for a massive reinvestment in, and policy support for, horticulture. • Both academics and civil society should examine the scope for encouraging demand for more home produced, sustainable horticulture and higher consumption of fruit and vegetables in the UK • Public health and environmental analysts should work more clearly on how to narrow the gap between supply of, and demand for, fruit and vegetables. Modelling studies as well as practical investigations should be funded. • A new research strand should be set up by the Government Research Councils into how to build demand for more sustainable home production. • A new more unified voice between all parties is needed to champion the British horticultural sector; this lack should be the subject of a joint inquiry by the Parliamentary Health, Environmental Audit and Environment, Food & Rural Affairs Committees