Epistemic Peer Disagreement

We offer a critical survey of the most discussed accounts of epistemic peer disagreement that are found in the recent literature. We also sketch an alternative approach in line with a pluralist understanding of epistemic rationality

Nitrate leaching and spring wheat bread making quality following cultivation of grasslands of different composition, age and management

The influence of sward botanical composition and ley age on grassland residual effects, quality of spring wheat and subsequent nitrate leaching was investigated. Grazed grasslands of different age (1, 2 and 8 production years) and composition (unfertilised grass-clover and fertilised perennial ryegrass) were ploughed and followed by spring wheat and spring barley. For reference, an adjacent field without grassland history but with the same crop sequence in 2002-2003 was treated with increasing quantities of N fertiliser. Yields and N uptake of spring wheat following grasslands always exceeded those of the reference plots with a history of cereal production. The nitrogen fertiliser replacement values of grass-clover and ryegrass were 59-100 and 72-121 kg ha-1, respectively, with the highest values representing the 8-year-old leys. Grain yield and N uptake increased while those for straw decreased with increasing ley age. There were no effects of previous grassland type (grass-clover/ryegrass) on content of protein, starch and gluten, but grassland age significantly influenced protein (P<0.05) and gluten (P<0.01) contents. It is suggested that N mineralisation following the ploughing of older grass leys occurred later than when following the 1st year ley. The protein and gluten contents of wheat following unfertilised grass-clover corresponded to those following cereals given 125-150 kg N ha-1, but the rheological properties of the gluten were different to what could be achieved using equivalent quantities of mineral fertiliser. Probably, the slow release of N from decomposition of old grassland gave a better synchrony between N release and plant demand. Nitrate leaching in year 1 after ploughing was significantly influenced by type of grassland (P<0.001) with 10 and 29 kg N ha-1 leached from grass-clover and ryegrass, respectively. Nitrate leaching following ploughing of 1-year-old leys averaged 11 kg N ha-1 which was significantly lower than the 24 kg N ha-1 following 2 or 8-year-old leys. The flow-weighted mean nitrate concentration decreased from 8.5 mg N l-1 in year 1 after grassland cultivation to 4.5 mg N l-1 in year 2. More N was released following ploughing of ryegrass swards and from grasslands of increasing age, but differences were moderate compared to the estimated N-surplus. This indicates that when organic matter in grasslands is partially decomposed and readily mineralisable N used, the remaining organic N is released only very slowly

Delayed soft X-ray emission lines in the afterglow of GRB 030227

Strong, delayed X-ray line emission is detected in the afterglow of GRB 030227, appearing near the end of the XMM-Newton observation, nearly twenty hours after the burst. The observed flux in the lines, not simply the equivalent width, sharply increases from an undetectable level (<1.7e-14 erg/cm^2/s, 3 sigma) to 4.1e-14 erg/cm^2/s in the final 9.7 ks. The line emission alone has nearly twice as many detected photons as any previous detection of X-ray lines. The lines correspond well to hydrogen and/or helium-like emission from Mg, Si, S, Ar and Ca at a redshift z=1.39. There is no evidence for Fe, Co or Ni--the ultimate iron abundance must be less than a tenth that of the lighter metals. If the supernova and GRB events are nearly simultaneous there must be continuing, sporadic power output after the GRB of a luminosity >~5e46 erg/s, exceeding all but the most powerful quasars.Comment: Submitted to ApJL. 14 pages, 3 figures with AASLaTe

Adiabatic Elimination in a Lambda System

This paper deals with different ways to extract the effective two-dimensional lower level dynamics of a lambda system excited by off-resonant laser beams. We present a commonly used procedure for elimination of the upper level, and we show that it may lead to ambiguous results. To overcome this problem and better understand the applicability conditions of this scheme, we review two rigorous methods which allow us both to derive an unambiguous effective two-level Hamiltonian of the system and to quantify the accuracy of the approximation achieved: the first one relies on the exact solution of the Schrodinger equation, while the second one resorts to the Green's function formalism and the Feshbach projection operator technique.Comment: 14 pages, 3 figure

Resveratrol given intraperitoneally does not inhibit the growth of high-risk t(4;11) acute lymphoblastic leukemia cells in a NOD/SCID mouse model.

The efficacy of resveratrol as a preventive agent against the growth of t(4;11) acute lymphoblastic leukemia (ALL) was evaluated in NOD.CB17-Prkdcscid/J mice engrafted with the human t(4;11) ALL SEM cell line. SEM cells were injected into the tail vein and engraftment was monitored by flow cytometry. Once engraftment was observed, mice were injected intraperitoneally with resveratrol (10 mg/kg body weight) dissolved in dimethylsulfoxide (DMSO) or DMSO alone (control) every other day, or vincristine (0.5 mg/kg body weight) 3 times per week for 4 weeks (n=16 per group). Comparisons of the percent of human leukemia cells in blood and survival curves showed resveratrol did not inhibit progression of the disease. Liquid chromatography-tandem mass spectrometry analyses of mouse sera showed resveratrol was rapidly metabolized to glucuronidated and sulfated forms 1 h post-injection, with low to no resveratrol or metabolites observed in sera by 24-48 h. These data indicate that in contrast to findings in in vitro models, parenterally administered resveratrol does not have potential as a preventive agent against high risk t(4;11) ALL

A repulsive reference potential reproducing the dynamics of a liquid with attractions

A well-known result of liquid state theory is that the structure of dense fluids is mainly determined by repulsive forces. The WCA potential, which cuts intermolecular potentials at their minima, is therefore often used as a reference. However, this reference gives quite wrong results for the viscous dynamics of the Kob-Andersen binary Lennard-Jones liquid [Berthier and Tarjus, Phys. Rev. Lett. 103, 170601 (2009)]. We show that repulsive inverse-power law potentials provide a useful reference for this liquid by reproducing its structure, dynamics, and isochoric heat capacity

Synthesis and analysis of jet fuel from shale oil and coal syncrudes

Thirty-two jet fuel samples of varying properties were produced from shale oil and coal syncrudes, and analyzed to assess their suitability for use. TOSCO II shale oil and H-COAL and COED syncrudes were used as starting materials. The processes used were among those commonly in use in petroleum processing-distillation, hydrogenation and catalytic hydrocracking. The processing conditions required to meet two levels of specifications regarding aromatic, hydrogen, sulfur and nitrogen contents at two yield levels were determined and found to be more demanding than normally required in petroleum processing. Analysis of the samples produced indicated that if the more stringent specifications of 13.5% hydrogen (min.) and 0.02% nitrogen (max.) were met, products similar in properties to conventional jet fuels were obtained. In general, shale oil was easier to process (catalyst deactivation was seen when processing coal syncrudes), consumed less hydrogen and yielded superior products. Based on these considerations, shale oil appears to be preferred to coal as a petroleum substitute for jet fuel production