Detection of irradiated foods by luminescence of contaminating minerals—effect of mineral composition on luminescence intensity

Laboratory irradiated rock and mineral samples were studied for their luminescence properties. The effect of alteration of feldspars on luminescence intensity was determined by the autoradiographic method for porphyritic granodiorite planar rock samples and with the TL reader for crushed minerals. Feldspars and quartz exhibited more intensive luminescence than mafic minerals, and luminescence of fresh K feldspar was the most intense. Potassium concentration did not have any effect on luminescence intensity for K feldspars but the intensity was highly dependent on the alteration degree of the mineral. Decrease in luminescence was found without a change in the element composition of the mineral and alteration was due to sericitization of K feldspar.     

Frequency distribution, isotopic composition and physical characterization of plutonium-bearing particles from the Fig-Quince zone on Runit Island, Enewetak Atoll

Runit Island on Enewetak Atoll was very heavily impacted by the U.S. nuclear testing campaign in the northern Marshall Islands (1946–58). The primary source of contamination on Runit Island was the 1958 Quince safety test where a large quantity of device plutonium (Pu) was scattered over the area near the GZ. A second low-yield device was detonated on the same site 10 days later, further disturbing the soil and leaving behind a very heterogeneous pattern of contamination including milligram-size particles of plutonium. A limited cleanup of the Fig-Quince zone was carried out in 1979. During this period, the effectiveness of the cleanup operations was primarily evaluated on the basis of bulk soil concentration data with little consideration given to the heterogeneity and long-term material-, biological-, and environmental-specific impacts of residual high activity (hot) particle contamination. The aim of the present study was twofold; (i) to characterize the levels and distribution of residual contamination in the Fig-Quince zone, and (ii) to develop pertinent data on the frequency distribution, elemental and isotopic composition, and physico-chemical properties of hot particles isolated from surface soils from Fig-Quince with a view towards providing recommendations on the future management and possible cleanup of the site. Today, Runit Island remains under an administrative quarantine.     

Efficient current reuse for low-power transceivers

Current boosting is a method where the performance of an active circuit block is optimized by placing a constant current source in parallel with the active signal path to provide optimal biasing for different components. In this paper, a technique to replace the constant dc current source with active building blocks typically required in transceivers is proposed. By using this method the total current consumption of the transceiver can be efficiently reduced without modifying its performance. A design example where the proposed technique reduces the receiver current consumption by 45% is given.     

Linear fractional transformations of Stieltjes functions

Linear fractional transformations of Stieltjes (and inverse Stieljes) functions, which appear naturally in the extension theory of nonnegative symmetric operators with defect one in Hilbert spaces, are investigated. (© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Boundary Relations, Unitary Colligations, and Functional Models

Recently a new notion, the so-called boundary relation, has been introduced involving an analytic object, the so-called Weyl family. Weyl families and boundary relations establish a link between the class of Nevanlinna families and unitary relations acting from one Kreĭn space, a basic (state) space, to another Kreĭn space, a parameter space where the Nevanlinna family or Weyl family is acting. Nevanlinna families are a natural generalization of the class of operator-valued Nevanlinna functions and they are closely connected with the class of operator-valued Schur functions. This paper establishes the connection between boundary relations and their Weyl families on the one hand, and unitary colligations and their transfer functions on the other hand. From this connection there are various advances which will benefit the investigations on both sides, including operator theoretic as well as analytic aspects. As one of the main consequences a functional model for Nevanlinna families is obtained from a variant of the functional model of L. de Branges and J. Rovnyak for Schur functions. Here the model space is a reproducing kernel Hilbert space in which multiplication by the independent variable defines a closed simple symmetric operator. This operator gives rise to a boundary relation such that the given Nevanlinna family is realized as the corresponding Weyl family. Received: January 21, 2008., Revised: March 31, 2008.     

Tilt: major factor in sterols' ordering capability in membranes

Using extensive atomistic simulations, we show that there is a single experimentally accessible parameter--the sterol tilt--that can be used to determine a sterol's capability to induce order, and thus to promote, e.g., formation of lipid rafts. The observations also facilitate designing new effective sterols.     

Isometric approximation property of unbounded sets

We give a necessary and sufficient quantitative geometric condition for an unbounded set A ? Rⁿ to have the following property with a given c > 0: For every ε ≥ 0 and for every map f: A → Rⁿ such that , there is an isometry T: A → Rⁿ such that ¦Tx?fx¦ ≤ cε for all x ∈ A.     

Weakly compact composition operators on vector-valued BMOA

Weak compactness of the analytic composition operator f?f○φ is studied on BMOA(X), the space of X-valued analytic functions of bounded mean oscillation, and its subspace VMOA(X), where X is a complex Banach space. It is shown that the composition operator is weakly compact on BMOA(X) if X is reflexive and the corresponding composition operator is compact on the scalar-valued BMOA. A concrete example is given which shows that BMOA(X) differs from the weak vector-valued BMOA for infinite dimensional Banach spaces X.