New interpretation of matter-antimatter asymmetry based on branes and possible observational consequences

Motivated by the AMS project, we assume that after the Big Bang or inflation epoch, antimatter was repelled onto one brane which is separated from our brane where all the observational matter resides. It is suggested that CP may be spontaneously broken, the two branes would correspond to ground states for matter and antimatter respectively. Generally a complex scalar field which is responsible for the spontaneous CP violation, exists in the space between the branes and causes a repulsive force against the gravitation. A possible potential barrier prevents the mater(antimatter) particles to enter the space between two branes. However, by the quantum tunnelling, a sizable anti-matter flux may come to our brane. In this work by considering two possible models, i.e. the naive flat space-time and Randall-Sundrum models and using the observational data on the visible matter in our universe as inputs, we derive the antimatter flux which would be observed by the AMS detector.Comment: 10 pages, 4 figures and 2 tables. Replaced by new versio

Do aeration conditions affect arsenic and phosphate accumulation and phosphate transporter expression in rice (Oryza sativa L.)?

Widespread contamination of rice with arsenic (As) has revealed a major exposure pathway to humans. The present study aimed to investigate the effects of oxygen in the rhizosphere on phosphate (P) transporter (for arsenate transportation) expressions, on As and P accumulation and As speciation in four rice genotypes. Oxygenation marginally increased root and shoot length. Total As concentrations in rice roots were dramatically reduced following aeration compared to stagnant treatments (p < 0.001). Aeration treatments significantly increased arsenate while reducing arsenite concentrations in roots (p < 0.001). Root arsenite concentrations were 1.5–2.5 times greater in stagnant than in aeration treatments. Total P concentrations in rice roots were dramatically increased following aeration compared to stagnant treatments. The relative abundance of phosphate transporter (inorganic phosphate transporter and phosphate/H+ symporter family protein) expressions showed downregulation in aeration treatments, particularly for SY-9586, XWX-17, and XWX-12 in inorganic phosphate transporter expressions and XWX-17 in phosphate/H+ symporter family protein expression (p < 0.05). The relative abundance of phosphate carrier protein expressions were relatively higher than the other phosphate transporters, showing upregulation in aeration treatments

Morphology-dependent enhancement of arsenite oxidation to arsenate on birnessite-type manganese oxide

Birnessite-type manganese oxide is a highly efficient oxidant that has been investigated widely for As(III) oxidation. Nevertheless As(III) oxidation rate is inevitably reduced due to favorable adsorption of coexisting ions and As(V) which passivate its surface. In this paper we explore a novel strategy to significantly improve As(III) oxidation performance by controlling birnessite morphology. The batch experiment results show that the nanoflower-like birnessite (Bir-NF) exhibits an incredible improvement in As(III) oxidation activity compared to nanowire-like (Bir-NW) and nanosheet-like (Bir-NS) birnessites. The morphology of birnessite varies from nanosheet to nanoflower not only promotes As(III) oxidation rate from 1.4 to 24.7 lmol g1 min1, but also reduces the adverse effect of adsorption of As(V) and coexisting ions on As(III) removal. The origin of morphology-dependent enhancement of As(III) removal was experimentally and theoretically studied by As(V) adsorption on birnessites, phosphate adsorption kinetics, detection of dissolved Mn2+ concentration, average Mn oxidation state, the point of zero charge, and density functional theory (DFT) calculations. The results reveal that significant enhancement of As(III) oxidation activity in Bir-NF as compared to Bir-NW and Bir-NS is attributed to its highly efficient contact between As(III) species and manganese oxide, as well as its fast charge transfer from As atom to Mn atom due to its highest oxygen vacancy defect concentration, thus significantly promoting As(III) oxidation activity

Acid transformation of bauxite residue: Conversion of its alkaline characteristics

Bauxite residue (BR) is a highly alkaline solid hazardous waste produced from bauxite processing for alumina production. Alkaline transformation appears to reduce the environmental risk of bauxite residue disposal areas (BRDAs) whilst potentially providing opportunities for the sustainable reuse and on-going management of BR. Mineral acids, a novel citric acid and a hybrid combination of acid-gypsum treatments were investigated for their potential to reduce residue pH and total alkalinity and transform the alkaline mineral phase. XRD results revealed that with the exception of andradite, the primary alkaline solid phases of cancrinite, grossular and calcite were transformed into discriminative products based on the transformation used. Supernatants separated from BR and transformed bauxite residue (TBR) displayed distinct changes in soluble Na, Ca and Al, and a reduction in pH and total alkalinity. SEM images suggest that mineral acid transformations promote macro-aggregate formation, and the positive promotion of citric acid, confirming the removal or reduction in soluble and exchangeable Na. NEXAFS analysis of Na K-edge revealed that the chemical speciation of Na in TBRs was consistent with BR. Three acid treatments and gypsum combination had no effect on Na speciation, which affects the distribution of Na revealed by sodium STXM imaging

Leaching optimization and dissolution behavior of alkaline anions in bauxite residue

Bauxite residue is a highly alkaline waste containing soluble alkaline anions, which can cause environmental concerns. The optimal leaching conditions, distribution of alkaline anions, types of pivotal alkaline anions and their dissolution behaviors were investigated based on the combination of single factors-orthogonal experiments and leaching stage experiment. Using a two-stage leaching, 86% of the soluble alkaline anions were leached with a L/S ratio of 2 mL/g, at 30 °C, over 23 h. During the first stage of leaching, approximately 88% of alkaline anions were leached from the dissolution of free alkali (NaOH, carbonate, bicarbonate, NaAl(OH)4) with the rest originating from the dissolution of alkaline minerals (calcite, cancrinite and hydrogarnet). Supernatant alkalinity was 69.78 mmol/L with accounting for 75%. Furthermore, carbonate leaching was controlled by solid film diffusion using the Stumm Model with an apparent activation energy of 10.24 kJ/mol

Dynamics of quantum dissipation systems interacting with Fermion and Boson grand canonical bath ensembles: Hierarchical equations of motion approach

A hierarchical equations of motion formalism for a quantum dissipation system in a grand canonical bath ensemble surrounding is constructed, on the basis of the calculus-on-path-integral algorithm, together with the parametrization of arbitrary non-Markovin bath that satisfies fluctuation-dissipation theorem. The influence functionals for both the Fermion or Boson bath interaction are found to be of the same path-integral expression as the canonical bath, assuming they all satisfy the Gaussian statistics. However, the equation of motion formalism are different, due to the fluctuation-dissipation theories that are distinct and used explicitly. The implications of the present work to quantum transport through molecular wires and electron transfer in complex molecular systems are discussed.Comment: 12page