in this study, the removal of cadmium and lead ions from aqueous solution by nanocrystalline magnetite was investigated. the nanocrystalline magnetite was synthesized by mechanochemical activation of hematite in a high energy planetary mill in argon atmosphere for 45 hours. the ability of the synthesized nanocrystalline magnetite for removal of cd(ii) and pb(ii) from aqueous solutions was studi...

A sequence of random variables is exchangeable if its joint distribution is invariant under variable permutations. We introduce exchangeable variable models (EVMs) as a novel class of probabilistic models whose basic building blocks are partially exchangeable sequences, a generalization of exchangeable sequences. We prove that a family of tractable EVMs is optimal under zeroone loss for a large...

Acid deposition and repeated biomass harvest have decreased soil calcium (Ca) availability in many temperate forests worldwide, yet existing methods for assessing available soil Ca do not fully characterize soil Ca forms. To account for discrepancies in ecosystem Ca budgets, it has been hypothesized that the highly insoluble biomineral Ca oxalate might represent an additional soil Ca pool that ...

A random partition of the positive integers is called partially exchangeable if for each finite sequence of positive integers n,, ... , nk, the probability that the partition breaks the first n1 + + nk integers into k particular classes, of sizes nl,.. . ., nk in order of their first elements, has the same value p(nl,...,nk) for every possible choice of classes subject to the sizes constraint. ...

Consider a (possibly infinite) exchangeable sequence X= {Xn : 1≤ n < N}, where N ∈ N ∪ {∞}, with values in a Borel space (A,A), and note Xn = (X1, . . . ,Xn). We say that X is Hoeffding decomposable if, for each n, every square integrable, centered and symmetric statistic based on Xn can be written as an orthogonal sum of n U statistics with degenerated and symmetric kernels of increasing order...

Total body potassium determined by whole-body monitoring and exchangeable body potassium estimated with (43)K were measured simultaneously in 12 patients with stable chronic renal failure. Values for the exchangeable potassium were obtained after equilibration periods of 24, 48, and 64 hours. The exchangeable body potassium, expressed as a percentage of the total body potassium (mean +/- S.E. o...

In partitioning-­‐-­‐-­‐a.k.a. clustering-­‐-­‐-­‐data, we associate each data point with one and only one of some collection of groups called clusters or partition blocks. Here, we formally establish an analogous problem, called feature allocation, for associating data points with arbitrary non-­‐negative integer numbers of groups, now called features or topics. Just as the exchangeable partit...