17 research outputs found

    Classification of a supersolid: Trial wavefunctions, Symmetry breakings and Excitation spectra

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    A state of matter is characterized by its symmetry breaking and elementary excitations. A supersolid is a state which breaks both translational symmetry and internal U(1) U(1) symmetry. Here, we review some past and recent works in phenomenological Ginsburg-Landau theories, ground state trial wavefunctions and microscopic numerical calculations. We also write down a new effective supersolid Hamiltonian on a lattice. The eigenstates of the Hamiltonian contains both the ground state wavefunction and all the excited states (supersolidon) wavefunctions. We contrast various kinds of supersolids in both continuous systems and on lattices, both condensed matter and cold atom systems. We provide additional new insights in studying their order parameters, symmetry breaking patterns, the excitation spectra and detection methods.Comment: REVTEX4, 19 pages, 3 figure

    Quantification of the influence of soil conditions on atrazine degradation rates

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    Atrazine degradation rates are known to vary in dependence of a range of environmental factors. In the present study we used statistical techniques to identify the major dependencies and to quantify these relationships. It was found that atrazine degradation rates can be related to depth, organic carbon content, and redox potential. Furthermore, the effects of previous treatment, carbon amendment, and saturation were quantified. The statistical models are based upon a vast number of observations, and therefore are expected to be more reliable than existing atrazine degradation models. The two major factors in atrazine degradation were identified to be the availability of substrate and the oxidation state of the soil. The here found model for redox dependent degradation of atrazine can now be incorporated into rate expressions that are used in biogeochemical transport models where the redox-state is routinely computed

    A facile enantioselective approach to neolignans

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    An enantioselective and stereoselective synthesis of 8-O-4' neolignans is reported in which a natural 8-0-4', norneolignan is enantioselectively synthesized as a single erythro isomer. Furthermore the route has been adapted to allow the enantioselective synthesis of 1,4-benzodioxane neolignans. (C) 2003 Elsevier Science Ltd. All rights reserved

    Removal of dissolved organics from produced water by forward osmosis

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    This study investigated the performance of the forward osmosis (FO) process for treating produced water. Water permeate flux and reverse salt flux (RSF) were examined at different feed pH values and operating configurations (i.e. FO, pressure retarded osmosis (PRO), and reverse osmosis (RO) modes). Acetic acid was selected as a model organic acid to present the dissolved organic fraction in produced water. Results reported here indicate that only membranes specifically designed for FO applications can be used in the FO and PRO modes. Due to the internal concentration polarization phenomenon, the PRO mode resulted in a higher water permeate flux and RSF than those in the FO mode. Acetate rejection was pH dependent in both the FO and RO modes. Furthermore, in the RO mode, acetate rejections by the FO membranes were higher than their nanofiltration counterparts. Results reported here suggest that FO can be a viable treatment option for the removal of dissolved organics from produced water

    A qualitative investigation into the characteristics and effects of music accompanying exercise

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    The purpose of the present study was to identify the characteristics of music used to accompany physical exercise and investigate the effects of such music using a qualitative approach. This work underpins the further development of a theoretical structure that is still relatively new. Semi-structured interviews were conducted with a sample of exercise participants (N = 13), seven males and six females, all with at least two years’ experience of exercising to music. An inductive content analysis of the interview data was undertaken and results contrasted with the conceptual model developed by Karageorghis et al. (1999) which describes the effects of musical and cultural factors with reference to psychophysical outcomes. The findings demonstrated the importance of musical (e.g. rhythm, lyrics, bass), contextual (e.g. time of day) and individual factors (e.g. background, personality) in determining both shortterm (e.g. mood, imagery) and long-term outcomes (e.g. heightened work-rate, endurance). The findings point towards a more expansive conceptual framework. In particular, facets of the response to music such as flow state, cognitive responses, rhythm response and anticipation are discussed. Music perceived to be motivating could lead to increases in exercise intensity and endurance during performance of self-regulated tasks. These findings have implications for the use of music in physical education settings

    Aporte de energia, composição e eficiência microbiana em bovinos alimentados com feno de capim-marandu e concentrado balanceados para diferentes ganhos de peso e potenciais de fermentação microbiana Energy aport, microbial composition and efficiency by bovines fed Brachiaria brizantha cv. Marandu hay and concentrate, balanced for different weight gains and potential of microbial fermentation

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    Um experimento foi realizado com o objetivo de avaliar o aporte de energia, a composição de bactérias e a eficiência microbiana por tourinhos Santa Gertrudes canulados no rúmen e no duodeno alimentados com dietas compostas de feno de capim-marandu e concentrado. Empregou-se o delineamento em quadrado latino 4 <FONT FACE=Symbol>&acute;</FONT> 4, no qual os tratamentos foram concentrados ajustados para ganho de peso corporal (GPC) diário de 0,5 e 1 kg/animal e potencial de fermentação microbiana (y) de 9,5 e 11 g de PB microbiana/MJ energia metabolizável fermentável. Houve diferença para as concentrações de nutrientes digestíveis totais (NDT) e energia metabolizável fermentável (EMFe) ingeridos e para a composição em matéria orgânica e mineral das bactérias ruminais para as dietas ajustadas para diferentes GPC. Houve interação significativa GPC <FONT FACE=Symbol>&acute;</FONT> y para a ingestão de NDT como porcentagem do peso corporal e a composição em PB e carboidratos totais das bactérias ruminais. Não foram encontradas diferenças para os potenciais de fermentação microbiana. A eficiência de síntese microbiana também não diferiu entre as dietas e apresentou valores de 12,7 g PB microbiana/100 g NDT e 9,2 g PB microbiana/MJ EMFe. As diferenças encontradas não justificaram o balanceamento dos concentrados para os diferentes potenciais de fermentação microbiana avaliados.<br>The experiment was carried out with the objective to evaluate the energy aport, microbial composition and efficiency of Santa Gertrudis young bulls, canulated in the rumen and duodenum, fed diets with palisadegrass hay and concentrates. A 4 x 4 latin square design was used, in which the treatments were composed by the concentrates adjusted for daily body weight gain (BWG) of 0.5 and 1 kg/animal and potential microbial fermentation (y) of 9.5 and 11 g microbial CP/MJ fermentable metabolizable energy. There were differences for the concentrations of total digestible nutrients (TDN) and fermentable metabolizable energy (FMEn) intakes, and for the composition in organic matter and mineral of ruminal bacteria for diets adjusted for different BWG. There was significant BWG x y interaction for TDN intake as percentage of body weight and in the CP and total carbohydrates composition of the ruminal bacteria. There were no differences for the potential microbial fermentation. The efficiency of microbial synthesis also did not differ among diets and showed values of 12.7 g microbial CP/100 g TDN and 9.2 g microbial CP/MJ FMEn. The observed differences did not justify the balancing of the concentrates for the different potential microbial fermentation evaluated
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