Investigating the generality of time-local master equations

Time-local master equations are more generally applicable than is often recognised, but at first sight it would seem that they can only safely be used in time intervals where the time evolution is invertible. Using the Jaynes-Cummings model, we here construct an explicit example where two different Hamiltonians, corresponding to two different non-invertible and non-Markovian time evolutions, will lead to arbitrarily similar time-local master equations. This illustrates how the time-local master equation on its own in this case does not uniquely determine the time evolution. The example is nevertheless artificial in the sense that a rapid change in (at least) one of the Hamiltonians is needed. The change must also occur at a very specific instance in time. If a Hamiltonian is known not to have such very specific behaviour, but is "physically well-behaved", then one may conjecture that a time-local master equation also determines the time evolution when it is not invertible.Comment: 7 pages, 6 figure

Middle part of the Mendoza River : water table level : 1986-1996

El área de surgencia del tramo medio del río Mendoza, está caracterizada hidrogeológicamente por afloramientos de vertientes que originan arroyos. Es la zona hortícola mas importante de Mendoza (Argentina), productora de verduras durante todo el año. Se practican no menos de dos cultivos anuales, en el mismo terreno, de lechuga, espinaca, repollo, coliflor, apio, ajo, cebolla, tomate y papa. Los suelos son intrazonales, ricos en materia orgánica, con tendencia a la salinización. En profundidad hay capas de arcillas que impiden o retardan la percolación de las aguas de riego. La topografía es suavemente ondulada en el sentido O-E. Tiene depresiones con afloramiento de vertientes, abundante durante el invierno, disminuyendo en primavera y tendiendo a la estabilización en verano. Con los registros 1989/96 de una red de freatímetros se confeccionaron tres planos de niveles freáticos: • isobatas mínimas absolutas • isobatas medias • isohipsas medias. Con el primer plano se establecieron 16 419  ha  (47,3  %  del  área  de  la  red freatimétrica) con niveles freáticos entre 0 y 1 m  de  profundidad.  La  superfiecie  para igual profundidad freática, según las isobatas medias fue de 1 496 ha (4,4 % del área precitada). Con las isohipsas medias se demostró la dirección SO-NE del flujo y la influencia de los arroyos en la descarga hídrica. De los hidrogramas anuales no se observa una correlación completa entre los volú- menes derivados en dique Cipolletti y los niveles freáticos medios en el área de estudio. El hidrograma de la serie 1989/96 revela que las profundidades freáticas medias oscilan entre 1,4 y 2,1 m pudiéndose observar un desfasaje -o retardo- de tres meses entre los aportes de agua y los niveles freáticos medios. Se recomendó mitigar las disminuciones de los caudales de las perforaciones y afloramientos de arroyos y vertientes como consecuencia de la puesta en funcionamiento del Dique Potrerillos. Igualmente, concluir el saneamiento del colector Pescara para mejorar rendimientos de cultivos y ambientales.The artesian aquifer area is in the middle reach of the Mendoza river has hidrogeological characteristics causing drainage outcrops and originating brooks. This important zone of Mendoza (Argentina) gives whole year vegetables. The agriculture is intensive, with never less than two cultivations a year in the same ground, of green salad, spinach, white cabbage, cauliflower, celery, garlic, onion, tomato and potato. Soils are intrazonal, rich in organic material, with tendency to salinization. Deeper claybeds stop or slow down percolation of irrigation waters. The topography is slow, shafting from W to E producing drainage outcrops in these depressions, most importants in winter, reduced in spring and established in summer. With water table mesurements of a piezometer network during 1989/96 were plotted three water table plans: • absolute minimum equal deep level lines • middle equal deep level lines • water table contour lines. The first plan shows that the surface with water table deepness between 0 and 1 meter is 16 419 ha (47,3 % of the piezometer network). For the middle equal deep level line plan by same water level deepness surface is 1 496 ha (4,4 %) and the water table contour line plan shows a groundwater flow from SW to NE and the influence the brooks have as discharges on the waterflow. From the anual hidrographs there is no complete correlation between derived volumes in the Cipolletti dike and the middle water table levels of the area observed. From the 1989/96 hidrograph datas results that water table depths are between 1,4 and 2,1 m, showing a non coincidence or delay of three months between the water yields and the middle water table levels. It is recomended to alleviate the reduction of the flow rates of the drillings and of the outcrops in the brook system and drainage as a conse-quence of the Potrerillos dike in function. Also, it is recomendated to make progress with the sanitation of the Pescara collector to get a better cultivated and environmental yield.Fil: Ortiz Maldonado, Gonzalo. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Ingeniería AgrícolaFil: Gómez, Hugo W. . Mendoza. Departamento General de Irrigació

Genome Sequence of the Photoarsenotrophic Bacterium Ectothiorhodospira sp. Strain BSL-9, Isolated from a Hypersaline Alkaline Arsenic-Rich Extreme Environment.

The full genome sequence of Ectothiorhodospira sp. strain BSL-9 is reported here. This purple sulfur bacterium encodes an arxA-type arsenite oxidase within the arxB2AB1CD gene island and is capable of carrying out "photoarsenotrophy" anoxygenic photosynthetic arsenite oxidation. Its genome is composed of 3.5 Mb and has approximately 63% G+C content

The effects of condensed tannins from Desmodium intortum and Calliandra calothyrsus on protein and carbohydrate digestion in sheep and goats

A factorial experiment was conducted to study the effects of condensed tannins (CT) from the tropical legumes Desmodium intortum and Calliandra calothyrus on the digestion and utilization of protein and carbohydrate in sheep and goats. CT-free Centrosema pubescens was also fed for comparison with the CT legumes, and each legume was included (300 g/kg DM) in a basal diet of pangola grass (Digitaria decumbens). Pangola grass alone was used as a control diet. There were no significant (P > 0.05) differences between sheep and goats for the efficiency of digestion of N (0.574, se 0.013), organic matter (OM; 0.519, SE 0.010), neutral-detergent fibre (NDF; 0.524, SE 0.011) and acid-detergent fibre (ADF; 0.407, SE 0.016). Diets containing desmodium and calliandra were digested less well in the rumen (64 and 62% of total OM digested) when compared with the pangola and centrosema diets (74 and 73% of total OM digested in rumen). There was an apparent net gain of 30% in ADF across the digestive tract sheep and goats given calliandra, and this gain was ascribed to the formation of 'artifact' fibre as a result of fibre-tannin interaction. Overall, inclusion of legume at 300 g/kg in the diet significantly increased (P 0.05) since animals given CT diets absorbed more N (19%) per kg total OM digested than those given the control diets. It was concluded that whilst the low levels of CT provided in desmodium (1.0%) and calliandra (2.3%) diets protected dietary protein from degradation in the rumen, there were no overall beneficial or detrimental effects of CT in these diets for sheep or goats. A method was developed to categorize CT into fractions representative of their forms (free, protein-bound, and fibre-bound) during the digestion process. A quantitative model of CT metabolism during passage through the digestive tract was developed from the measured exchanges of CT between free, protein-bound and fibre-bound pools in the rumen and lower digestive tract. CT interchange mainly occurred in the reticulo-rumen of both animal species. Desmodium and calliandra free CT showed net losses of 68 and 78% in the rumen respectively and 57 and 68% of the fibre-bound CT was lost in the same site for sheep and goats respectively. However, protein-bound CT increased across the rumen by 73 and 56% for both animal species. Post-rumen losses of the total CT abomasal flow were 86 and 83% (free CT) for sheep and goats respectively, 70 and 66% (protein-bound CT), whilst 28% loss of fibre-bound CT occurred in sheep and goats respectively

Response versus Chain Length of Alkanethiol-Capped Au Nanoparticle Chemiresistive Chemical Vapor Sensors

Au nanoparticles capped with a homologous series of straight chain alkanethiols (containing 4−11 carbons in length) have been investigated as chemiresistive organic vapor sensors. The series of alkanethiols was used to elucidate the mechanisms of vapor detection by such capped nanoparticle chemiresistive films and to highlight the molecular design principles that govern enhanced detection. The thiolated Au nanoparticle chemiresistors demonstrated rapid and reversible responses to a set of test vapors (n-hexane, n-heptane, n-octane, iso-octane, cyclohexane, toluene, ethyl acetate, methanol, ethanol, isopropanol, and 1-butanol) that possessed a variety of analyte physicochemical properties. The resistance sensitivity to nonpolar and aprotic polar vapors systematically increased as the chain length of the capping reagent increased. Decreases in the nanoparticle film resistances, which produced negative values of the differential resistance response, were observed upon exposure of the sensor films to alcohol vapors. The response signals became more negative with higher alcohol vapor concentrations, producing negative values of the sensor sensitivity. Sorption data measured on Au nanoparticle chemiresistor films using a quartz crystal microbalance allowed for the measurement of the partition coefficients of test vapors in the Au nanoparticle films. This measurement assumed that analyte sorption only occurred at the organic interface and not the surface of the Au core. Such an assumption produced partition coefficient values that were independent of the length of the ligand. Furthermore, the value of the partition coefficient was used to obtain the particle-to-particle interfacial effective dielectric constant of films upon exposure to analyte vapors. The values of the dielectric constant upon exposure to alcohol vapors suggested that the observed resistance response changes observed were not significantly influenced by this dielectric change, but rather were primarily influenced by morphological changes and by changes in the interparticle spacing

Linearly independent pure-state decomposition and quantum state discrimination

We put the pure-state decomposition mathematical property of a mixed state to a physical test. We begin by characterizing all the possible decompositions of a rank-two mixed state by means of the complex overlap between two involved states. The physical test proposes a scheme of quantum state recognition of one of the two linearly independent states which arise from the decomposition. We find that the two states associated with the balanced pure-state decomposition have the smaller overlap modulus and therefore the smallest probability of being discriminated conclusively, while in the nonconclusive scheme they have the highest probability of having an error. In addition, we design an experimental scheme which allows to discriminate conclusively and optimally two nonorthogonal states prepared with different a priori probabilities. Thus, we propose a physical implementation for this linearly independent pure-state decomposition and state discrimination test by using twin photons generated in the process of spontaneous parametric down conversion. The information-state is encoded in one photon polarization state whereas the second single-photon is used for heralded detection.Comment: 6 pages, 5 figures, Submitted to Phys. Rev.

Incorporation of alpha-Ketoglutaric Acid as a Fixed Bed Scrubber Media for the Neutralization of Hydrazine Family Hypergolic Fuels

A candidate scrubber media, alpha-ketoglutaric acid (aKGA) adsorbed onto a silica-based substrate was examined as a potential alternative to the hydrazine-family hypergolic fuel neutralization techniques currently utilized at NASA/Kennedy Space Center (KSC). Helvenson et. al. has indicated that aKGA will react with hydrazines to produce non-hazardous, possibly biodegradable products. Furthermore, the authors have previously tested and demonstrated the use of aKGA aqueous solutions as a replacement neutralizing agent for citric acid, which is currently used as a scrubbing agent in liquid scrubbers at KSC. Specific properties examined include reaction efficiency, the loading capacity of aKGA onto various silica substrates, and the comparison of aKGA media performance to that of the citric acid vapor scrubber systems at KSC and a commercial vapor scrubber media. Preliminary investigations showed hydrophobic aerogel particles to be an ideal substrate for the deposition of the aKGA. Current studies have shown that the laboratory produced aKGA-Aerogel absorbent media are more efficient and cost effective than a commercially available fixed bed scrubber media, although much less cost effective than liquid-based citric acid scrubbers (although possibly safer and less labor intensive). A comparison of all three alternative scrubber technologies (liquid aKGA, solid-phase aKGA, and commercially available sorbent materials) is given considering both hypergolic neutralization capabilities and relative costs (as compared to the current citric acid scrubbing technology in use at NASA/KSC)