Conditional negative association for competing urns

We prove conditional negative association for random variables x _j = 1 (j∈[n]:= {1…n}) , where σ(1)…σ(m) are i.i.d. from [n]. (The σ(i) 's are thought of as the locations of balls dropped independently into urns 1…n according to some common distribution, so that, for some threshold t_j, x _j is the indicator of the event that at least t_j balls land in urn j.) We mostly deal with the more general situation in which the σ(i) 's need not be identically distributed, proving results which imply conditional negative association in the i.i.d. case. Some of the results—particularly Lemma 8 on graph orientations—are thought to be of independent interest. We also give a counterexample to a negative correlation conjecture of D. Welsh, a strong version of a (still open) conjecture of G. Farr. © 2012 Wiley Periodicals, Inc. Random Struct. Alg., 2012     

Interference swapping in scattering from a nonlocal quantum target

We describe a new and distinctive interferometry in which a probe particle scatters off a superposition of locations of a single free target particle. Probe particles scattering off a single free "mirror" (in one dimension) or a single free "slit" (in two dimensions) can "swap" interference with the superposed target states. The condition for interference is loss of orthogonality of the target states and reduces, in simple examples, to transfer of orthogonality from target to probe states. We analyze experimental parameters and conditions necessary for interference to be observed.     

Radiological dose assessment of naturally occurring radioactive materials in concrete building materials

Previous studies have shown that the natural radioactivity contained in building materials have significantly influenced the dose rates in dwelling. Exposure to natural radiation in building has been of concerned since almost 80 % of our daily live are spend indoor. Thus, the aim of the study is to assess the radiological risk associated by natural radioactivity in soil based building materials to dwellers. A total of 13 Portland cement, 46 sand and 43 gravel samples obtained from manufacturers or bought directly from local hardware stores in Peninsular of Malaysia were analysed for their radioactivity concentrations. The activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K in the studied building materials samples were found to be in the range of 3.7–359.3, 2.0–370.8 and 10.3–1,949.5 Bq kg^?1 respectively. The annual radiation dose rates (μSv year^?1) received by dwellers were evaluated for 1 to 50 years of exposure using Resrad-Build Computer Code based on the activity concentration of ²²⁶Ra, ²³²Th and ⁴⁰K found in the studied building material samples. The rooms modelling were based on the changing parameters of concrete wall thickness and the room dimensions. The annual radiation dose rates to dwellers were found to increase annually over a period of 50 years. The concrete thicknesses were found to have significantly influenced the dose rates in building. The self-absorption occurred when the concrete thickness was thicker than 0.4 m. Results of this study shows that the dose rates received by the dwellers of the building are proportional to the size of the room. In general the study concludes that concrete building materials; Portland cements, sands, and gravels in Peninsular of Malaysia does not pose radiological hazard to the building dwellers.     

Zeaxanthin Production by Novel Marine Isolates from Coastal sand of India and its Antioxidant Properties

Zeaxanthin carotenoids are class of commercially important natural products and diverse biomolecules produced by plants and many microorganisms. Bacteria often produce a cocktail of polar and nonpolar carotenoids limiting their industrial applications. Marine members of the family Flavobacteriaceae are known to produce potential carotenoids such as astaxanthin and zeaxanthin. A few bacterial species have been reported for the predominant production zeaxanthin. Here, we report the molecular identification of the zeaxanthin as a major carotenoid produced by two novel bacteria (YUAB-SO-11 and YUAB-SO-45) isolated from sandy beaches of South West Coast of India and the effect of carbon sources on the production of zeaxanthin. The strains were identified based on the 16S rRNA gene sequencing as a member of genus Muricauda. The closest relatives of YUAB-SO-11 and YUAB-SO-45 were Muricauda aquimarina (JCM 11811^T) (98.9 %) and Muricauda olearia (JCM 15563^T) (99.2 %), respectively, indicating that both of these strains might represent a novel species. The highest level of zeaxanthin production was achieved (YUAB-SO-11, 1.20?±?0.11 mg g^?1) and (YUAB-SO-45, 1.02?±?0.13 mg g^?1) when cultivated in marine broth supplemented with 2 % NaCl (pH 7) and incubated at 30 °C. Addition of 0.1 M glutamic acid, an intermediate of citric acid cycle, enhanced the zeaxanthin production as 18 and 14 % by the strains YUAB-SO-11 and YUAB-SO-45 respectively. The zeaxanthin showed in vitro nitric oxide scavenging, inhibition of lipid peroxidation, and 2,2-diphenyl-1-picryl hydrazyl scavenging activities higher than the commercial zeaxanthin. The results of this study suggest that two novel strains YUAB-SO-11 and YUAB-SO-45 belonging to genus Muricauda produce zeaxanthin as a predominant carotenoid, and higher production of zeaxanthin was achieved on glutamic acid supplementation. The pigment showed good in vitro antioxidant activity, which can be exploited further for commercial applications.     

Solid state interaction between V2O5 and MoO3: specific features related to minor vanadia transfer

Vanadia transport, which is a minor reaction flux in the solid state reaction between V₂O₅ and MoO₃, was studied using chemical and neutron activation analyses and electron spectroscopy for chemical analysis. It was found that negligible quantities of vanadia were transferred in a molybdena briquette during the reaction. Vanadia was presumably localized in thin external layers of molybdena grains. The reaction potential difference U _r across a Pt|MoO₃|V₂O₅|Pt cell was studied. It was shown that in this cell U _r was produced at the molybdena briquette and was due to vanadia transport. The U _r value changed with time in two stages. The reaction potential difference U _r was constant (or diminished slightly) at the first stage and dropped abruptly at the second stage. The duration of the first stage depended on the initial thickness of the MoO₃ briquette: the thicker the briquette, the longer the U _r value was nearly constant. Causes and probable mechanisms of U _r generation are discussed in different terms: chemical reaction, variation of a _{O 2} at the boundary between the reaction product and initialoxides, or surface spreading of the minor (V₂O₅ or V₉Mo₆O₄₀) diffusant. The last mechanism, which received the least study in the general case, was shown to be the most probable one for the reaction at hand. Electronic Publication     

Conductivity and hydration of lanthanum-substituted barium calcium niobates Ba4 ? xLaxCa2Nb2O11 + 0.5x (x = 0.5; 1; 1.5)

A double perovskite Ba₄(Ca₂Nb₂)O₁₁ known as the oxygen-ionic and protonic conductor is modified by substitution of La atoms for Ba atoms in its composition. Three phases with different lanthanum contents Ba_{4 − x} La _x Ca₂Nb₂O_{11 + 0.5x} with x = 0.5; 1; 1.5 are studied. The temperature dependences of conductivity are measured and the thermogravimetric studies are carried out. The thermogravimetric curves of heating are close for all three compounds, whereas their curves of cooling strongly differ from one another. For compositions with x = 0.5 and 1.5, the dependences of conductivity on the partial oxygen pressure P_O2 P_{O_2 } and the partial water vapor pressure P_{H2 O}P_{H_2 O} are measured. The total transport numbers of ions and the transport numbers of protons are calculated. It is shown that the slope of the logs_tot ( logP_{H2 O} )_Tlog\sigma _{tot} \left( {logP_{H_2 O} } \right)_T dependence reaches 1/3 in the range of medium P_{H2 O}P_{H_2 O} under the condition of electroneutrality 2[O″ _V ] = [H* _i ], which coincides with the result obtained earlier for the Ba₄Ca₂Nb₂O₁₁ (x = 0) composition and the solid solutions on its basis with different Ba/Ca ratios. The obtained results are compared with the literature data describing the incorporation of water into Ba₂In₂O₅ and BaCe_0.89(Y_0.2)O_2.9.