bluuebunny/crossref_metadata_2025_split huggingface dataset:
Generation of streamflow to seasonal high waters in a freshwater delta, northwestern Canada
Authors: Peters Daniel L. , Prowse Terry D. 
Published: November 2006

AbstractShallow lakes and wetlands in the Peace‐Athabasca Delta (PAD), one of the world's largest freshwater deltas located in northwestern Canada, are dependent on occasional flooding to replenish evaporated water. The hydrology of the PAD has experienced natural and human induced changes in recent times. Since the early 1970s, there has been a desire to restore water to perched wetlands by managing inundation of the perimeter deltas. Before such plans are implemented, it is important to understand the generation of annual peak ice‐induced and open‐water floodwaters to this Nordic delta. The hydroclimatology, physiography, size, and relative locations of sub‐basins exert a strong control on the runoff response. Ice‐jam floods in the lower Athabasca and Peace Rivers are generated by large snowmelt runoff from ‘trigger tributaries’ located in the downstream (foothills and plains) portions of the basin. Flood flows during the open‐water period are primarily generated by heavy rainfall runoff originating from the more elevated foothill/mountain regions where the precipitation process is enhanced by orography. In general, storage of alpine runoff in the headwaters of the Peace River places an increased dependence on downstream tributaries of the system to produce extreme flow events to the delta. Recommendations are made for additional hydrological modelling studies to assess the potential change to generation of extreme events from additional water retention/diversion schemes, land‐use change, and a changing hydroclimate within the upstream contributing basins of the PAD. Copyright © 2006 Crown in the right of Canada. Published by John Wiley & Sons, Ltd.
A new approach to measuring the aerodynamic resistance to evaporation within a northern peatland using a modified Bellani plate atmometer
Authors: Kettridge Nicholas , Baird Andrew 
Published: November 2006

AbstractThis study considers evaporation from northern peatlands, which are important global stores of soil carbon. Evaporation is commonly simulated using the Penman–Monteith model. The model incorporates the aerodynamic resistance to vapour transfer (ra), which can currently only be measured using expensive, labour intensive micro‐meteorological methods. A new approach to measuring ra is presented. The approach involves accurately measuring the evaporation from a modified Bellani plate atmometer, of known surface resistance and temperature. With knowledge of basic meteorological parameters, ra can then be calculated. The approach is compared to modelled resistances within a northern peatland: no significant difference was found between modelled and measured ra. Copyright © 2006 John Wiley & Sons, Ltd.
Structure of a paramagnetic supermicroporous silica‐based material via a multinuclear solid‐state NMR monitoring
Authors: Bakhmutov Vladimir I. , Shpeizer Boris G. , Clearfield Abraham 
Published: November 2006

AbstractThe paramagnetic Si/Al material doped with 19.8% (weight) of Mn2+ has been characterized by the 1H, 13C, 27Al, 29Si MAS NMR spectra and the 1H, 29Si T1MAS relaxation measurements as a gel dried at 130 °C and as samples calcined at 504, 540 and 650 °C. It has been demonstrated that in spite of strong paramagnetic effects, NMR monitoring in combination with 29Si T1 relaxation experiments can be successful for structural descriptions of porous materials. Copyright © 2007 John Wiley & Sons, Ltd.
Maximum independent set for intervals by divide and conquer with pruning
Authors: Snoeyink Jack 
Published: November 2006

AbstractSuppose a given set of n intervals contains a maximum independent set of k disjoint intervals. This brief note demonstrates that “divide and conquer with pruning” produces an easy, output‐sensitive O(n log k)‐time algorithm to compute such a maximum independent set. © 2006 Wiley Periodicals, Inc. NETWORKS, Vol. 49(2), 158–159 2007
The stochastic time–cost tradeoff problem: A robust optimization approach
Authors: Cohen Izack , Golany Boaz , Shtub Avraham 
Published: November 2006

AbstractWe consider the problem of allocating resources to projects performed under given due dates and stochastic time–cost tradeoff settings. In particular, we show how to implement a state‐of‐the‐art methodology known as “robust optimization” to solve the problem. In contrast to conventional approaches, the model we develop results in management policies rather than optimal values for the original decision variables. Hence, the project manager can postpone decisions to the point of time when they are actually required and then make them according to the optimal policy (which employs cumulative data on the project progress). The solutions are guaranteed to be robust—that is, ensuring feasibility except when the uncertain parameters assume extreme values. Still, as we demonstrate through an extensive numerical example, the price we need to pay to obtain that robustness is relatively small even for high uncertainty levels. © 2006 Wiley Periodicals, Inc. NETWORKS, Vol. 49(2), 175–188 2007
Gas‐phase kinetics of the reactions of O(3P) atoms with (Z)‐CHClCHCl, CCl2CH2, CCl2CCl2 and (E/Z)‐CFClCHCl at 298 K
Authors: Blanco María B. , Cometto Pablo M. , Taccone Raúl A. , Lane Silvia I. , Teruel Mariano A. 
Published: November 2006

AbstractThe kinetics of the gas‐phase reactions of O(3P) atoms with (Z)‐CHClCHCl, CCl2CH2, CCl2CCl2 and (E/Z)‐CFClCHCl were studied at 298 K using a discharge flow tube system. The overall rate constants based on the measured afterglow reactions were (2.0 ± 0.2) × 10−13, (11.3 ± 0.9) × 10−13, (1.9 ± 0.3) × 10−13, and (1.4 ± 0.3) × 10−14, respectively, all in units of cm3 molecule−1 sec−1. The experiments were carried out under pseudo‐first‐order conditions with [O(3P)]0 ≪ [chloroethene]. Halogen substitution in the alkenes is discussed in terms of reactivity with O(3P) and its relation to the ionization potential and the reactivity with OH radicals. Copyright © 2006 John Wiley & Sons, Ltd.
Rate constants for reaction of Cl atoms with hydrofluoroethers
Authors: Dalmasso Pablo R. , Nieto Jorge D. , Taccone Raúl A. , Teruel Mariano A. , Lane Silvia I. 
Published: November 2006

AbstractThe relative rate technique was used to measure the rate constants for the reactions of Cl atoms with CHF2OCH2CF3 and CHF2OCHFCF3. Experiments were carried out at 296 ± 2 K and atmospheric pressure using nitrogen as the bath gas. Using 1,1,1‐trichloroethane and 1,1,1,2‐tetrafluoroethane as the reference compounds, the following rate coefficients were derived: k(Cl + CHF2OCH2CF3) = (1.14 ± 0.27) × 10−14 and k(Cl + CHF2OCHFCF3) = (1.20 ± 0.12) × 10−15, in units of cm3 molecule−1 s−1. The rate constants obtained are compared with the literature data. The implications of the results with regard to the atmosphere are briefly considered. Copyright © 2006 John Wiley & Sons, Ltd.
Equivalent circuit analysis of the stability diagram of a few electron triple quantum dots
Authors: Gaudreau L. , Sachrajda A. S. , Studenikin S. , Zawadzki P. , Lapointe J. , Kam A. 
Published: November 2006

AbstractRecent developments in single and double electrostatically confined quantum dots have shown that these devices are promising candidates for the implementation of quantum computation schemes in solid state systems. One of the obstacles for such an accomplishment is scalability. We present here the first realization of a triple lateral quantum dot with a few number of electrons, going down to fundamental configurations such as the vacuum state (no electrons in the system) or one electron in each quantum dot. New phenomena unseen in single or double dots are revealed involving charge and spin reconfigurations within the system, reminiscent of quantum cellular automata (QCA) functionalities. More importantly, it is necessary to understand these phenomena for they will be present in any three or more coupled quantum dots system. An equivalent circuit analysis of the system is used to reproduce these new features and to highlight some differences between experiments and the model, possibly arising from quantum phenomena not included in the circuit analysis. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Theoretical modelling of electron transport in InAs/GaAs quantum dot superlattices
Authors: Vukmirović Nenad , Ikonić Zoran , Savić Ivana , Indjin Dragan , Harrison Paul 
Published: November 2006

AbstractA theoretical model describing the electron transport in InAs/GaAs quantum dot infrared photodetectors, modelled as ideal quantum dot superlattices, is presented. The carrier wave functions and energy levels were evaluated using the strain dependent 8‐band k · p Hamiltonian and used to calculate all intra‐ and inter‐period transition rates due to interaction with phonons and electromagnetic radiation. The interaction with longitudinal acoustic phonons and electromagnetic radiation was treated perturbatively within the framework of Fermi's golden rule, while the interaction with longitudinal optical phonons was considered taking into account their strong coupling to electrons. The populations of energy levels were then found from a system of rate equations, and the electron current in the superlattice was subsequently extracted. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A hybrid model for the magneto‐optics of embedded nano‐objects
Authors: Wijers C. M. J. , Voskoboynikov O. , Liu J. L. 
Published: November 2006

AbstractThe influence of the surrounding semiconducting matrix upon the polarizability of embedded nano‐objects (nano‐rings) has been investigated using a hybrid discrete/continuum model. It describes embedded systems by excess discrete dipoles with excess polarizability against a uniform background with the host material dielectric constant. The polarizability combines the static polarizability of an ellipsoidal ring with a dynamic quantum mechanical frequency dependent term. The result of the model for the particular nano‐ring host combination investigated is an increased internal reflectance and an overall strong increment of the structure in reflectance/ellipsometric angles, displaying clearly the optical Aharonov‐Bohm effect. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
1.5 µm luminescence from InAs/GaxIn1–xNyAs1–y quantum dots grown on GaAs substrate
Authors: Richter M. , Hugues M. , Damilano B. , Massies J. , Duboz J.‐Y. , Reuter D. , Wieck A. D. 
Published: November 2006

AbstractSelf‐assembled InAs quantum dots encapsulated by Gax In1–x Ny As1–y (GINA) have been grown on GaAs (001) substrate by solid source molecular beam epitaxy. A wavelength of up to 1.52 µm is achieved for as‐grown samples with y = 1.7%. The growth temperature of the GINA cap layer and the ex‐situ annealing temperature are optimized in order to get the best photoluminescence characteristics. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Time resolved measurements on low‐density single quantum dots at 1300 nm
Authors: Zinoni C. , Alloing B. , Monat C. , Li L. H. , Lunghi L. , Gerardino A. , Fiore A. 
Published: November 2006

AbstractWe present time integrated and time resolved measurements on single In/As quantum dots (QD) emitting at 1300 nm, at 10 K, embedded in a planar microcavity. We clearly identify a standard spectroscopic signature from single QDs and to compare the exciton line width and biexciton (BX) binding energy for several QDs. We present this data for QDs spatially selected by etched mesas and metallic apertures. Time resolved photoluminescence (PL) from single electron‐hole recombination in the ground state of the QD is investigated as a function of excitation power and temperature. The measurements reveal the presence of a background emission that delays the PL of excitons in the ground state. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Temperature dependence of photoluminescence of CdSe/ZnSe quantum dots grown on GaAs and Si/Ge virtual substrates
Authors: Onishchenko Evgeny E. , Bagaev Victor S. , Kazakov Igor P. , Rzaev Murvetali M. 
Published: November 2006

AbstractWe have carried out temperature‐dependent studies of the photoluminescence properties of a set of CdSe/ZnSe quantum dot structures grown on conventionally used GaAs(100) substrates and Si(100)/Ge virtual substrates. Both single‐layer and multilayer QD structures have been studied. It was shown that the conventional MBE technique allows to grow CdSe/ZnSe QDs having the activation energy of luminescence quenching as large as 200 meV. Such issues as possible reasons of such a large activation energy and exciton migration in QD planes are discussed. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Valence band mixing in charged self‐assembled quantum dots
Authors: Léger Y. , Besombes L. , Maingault L. , Mariette H. 
Published: November 2006

AbstractWe analyze the optical emission of neutral, positively and negatively charged excitons in single II‐VI quantum dots presenting a high degree of linear polarization. This linear polarization is attributed to a valence band mixing and we show that in QDs combining both a shape anisotropy and an anisotropic in‐plane strain distribution, the linear polarization direction of the exciton are controlled by an interplay of the valence band mixing and e‐h exchange interaction. Similarly, under strong transverse magnetic field, the direction of the linearly polarized emission of the charged excitons are simultaneously controlled by the valence band mixing and the direction of the magnetic field. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Origin of asymmetric splitting of a neutral exciton in a single semiconductor quantum dot
Authors: Suemune I. , Kumano H. , Kimura S. , Sasakura H. , Adachi S. , Muto S. , Song H. Z. , Hirose S. , Usui T. 
Published: November 2006

AbstractIt is well‐recognized that exciton‐state energy splitting makes it difficult to generate entangled photon pairs (EPP) from a single quantum dot (QD). It will be shown that the splitting of the exciton states originates from not only QD anisotropy but also ionization of residual impurities. This result shows that the growth of highly pure barrier layers will be necessary for the generation of EPP. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
InN quantum dots grown on GaN (0001) by molecular beam epitaxy
Authors: Dimakis E. , Georgakilas A. , Iliopoulos E. , Tsagaraki K. , Delimitis A. , Komninou Ph. , Kirmse H. , Neumann W. , Androulidaki M. , Pelekanos N. T. 
Published: November 2006

AbstractThe growth properties of InN quantum dots on GaN (0001) surfaces by molecular beam epitaxy are being investigated. The dependence of the dimensions and density of the dots on the nucleation temperature and their evolution during growth at a constant substrate temperature are described. It is shown that both dimensions and density can be accurately controlled through nucleation temperature and deposition time. In the range from 400 °C to 450 °C, the formation of InN quantum dot structures of small dimensions and high density is feasible. InN dots with less than 3nm height, less than 22 nm diameter and with density higher than 1.7×1011 cm–2 have been obtained. Finally, vertical alignment of dots was observed for a multi‐period InN quantum dot structure in GaN matrix, grown at 430 °C. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Inserting one single Mn ion into a quantum dot
Authors: Maingault L. , Besombes L. , Léger Y. , Mariette H. , Bougerol C. 
Published: November 2006

AbstractMethod of growth to get one single Mn ion in a Quantum Dot (QD) is presented. A simple analysis and a more realistic simulation prove that a low concentration of Mn is needed in order to have a maximum of QD with only one Mn. This is reached by using a ZnTe spacer after a Zn1–xMnxTe layer: Mn segregates in the ZnTe spacer and actually incorporates into the QDs. A study of photoluminescence spectra of samples with different spacer thicknesses validates this approach. A wavefunction modelisation and its application is also presented giving proofs of the importance of Mn position into the dot. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Introducing reliability and load balancing in mobile IPv6‐based networks
Authors: Faizan Jahanzeb , EL‐Rewini Hesham , Khalil Mohamed 
Published: November 2006

AbstractMobile IPv6 is an enabling platform for creating IP mobility in the evolution path towards next generation service offerings. However, Mobile IPv6 does not provide reliability and load balancing in the network. In this paper, we introduce ‘Virtual HA Reliability Protocol.’ It is an extension to Mobile IPv6 that introduces reliability and load balancing in the Mobile IPv6‐based networks. It also provides solutions to the problems caused due to Home Agent failures in Mobile IPv6. These problems are: delayed failure detection, service interruption in the upper layer applications, increased workload on the Mobile Node, message overhead over the air interface, and IPsec Security Associations re‐establishment.We also present the results of several experiments to assess the performance of our solution. The results show that our solution provides transparent Home Agent failure detection and recovery mechanisms. As a result, there is a significant reduction in message exchange over the air interface. Also, our solution provides high service availability in the upper layer applications. Moreover, there is reduced workload on the Mobile Node. Finally, the load balancing mechanism of our solution provides efficient, dynamic, and transparent load balancing among the multiple Home Agents. Thus our solution improves the overall Mobile IPv6 and upper layer applications performance. Copyright © 2006 John Wiley & Sons, Ltd.
Optimized bandwidth allocation with fairness and service differentiation in multimedia wireless networks
Authors: Nasser Nidal , Hassanein Hossam 
Published: November 2006

AbstractIn this article we present an optimal Markov Decision‐based Call Admission Control (MD‐CAC) policy for the multimedia services that characterize the next generation of wireless cellular networks. A Markov decision process (MDP) is used to represent the CAC policy. The MD‐CAC is formulated as a linear programming problem with the objectives of maximizing the system utilization while ensuring class differentiation and providing quantitative fairness guarantees among different classes of users. Through simulation, we show that the MD‐CAC policy potentially achieves the optimal decisions. Hence our proposed MD‐CAC policy satisfies its design goals in terms of call‐class‐differentiation, fairness and system utilization. Copyright © 2006 John Wiley & Sons, Ltd.
Preparation and properties of an apoprotein derivative of human serum β‐lipoprotein
Authors: Gotto A. M. , Levy R. I. , Fredrickson D. S. 
Published: November 2006

AbstractThe aim of this study was to develop a convenient method for the preparation and study of a soluble delipidated form of human serum β‐lipoprotein. This was achieved by succinylation and delipidation with ether‐ethanol (3∶1). The succinylated apoprotein was soluble in either 0.13 M Tris‐HCl buffer, pH 8.2 (for β‐lipoprotein prepared by ultracentrifugation) or in the same Tris buffer to which 5 mM sodium decyl sulfate was added (for heparin‐Mn precipitated β‐lipoprotein). The immunological activity of β‐lipoprotein or its apoprotein were markedly altered by succinylation. Whereas the succinylated β‐lipoprotein appeared as one peak in the analytical ultracentrifuge, the succinylated apoprotein appeared as two. Under the electron microscope β‐lipoprotein and succinylated β‐lipoprotein were indistinguishable, appearing as uniform preparations of spherical particles 215 to 220 A in diamater.
Oxygenated fatty acids of oil from sunflower seeds after prolonged storage
Authors: Mikolajczak K. L. , Freidinger R. M. , Smith C. R. , Wolff I. A. 
Published: November 2006

AbstractsChemical analysis of a number of sunflower (Helianthus annuus) seed oil samples revealed a low and variable percentage of hydrogen bromide‐reactive material. To characterize the compounds responsible for this reactivity, oil was extracted from selected introductions from Uruguay, Turkey, and Yugoslavia that had been subjected to prolonged storage. Two epoxy fatty acids and two conjugated dienolic acids were isolated from the methyl esters derived from these sunflower seed oils by using a combination of column chromatography and countercurrent distribution. The epoxy acids arecis‐9,10‐epoxystearic acid (0.5%) andcis‐9,10‐epoxy‐cis‐12‐octadecenoic (coronaric) acid (2.2%). Characterization of the dienols revealed that they are 9‐hydroxy‐trans‐10,cis‐12‐octadecadienoic acid (1.2%) and 13‐hydroxy‐cis‐9,trans‐11‐octadecadienoic acid (1.3%). Fresher seed of some of these introductions contained less of the oxygenated components.Oil from recently produced seed of selected high‐oil Russian sunflower varieties, including some currently grown in the United States, contained no more than trace amounts of oxygenated acids. Though the relative contributions of genetic and environmental factors toward genesis of oxygenated acids are not established, increase of those acids in some sunflower lines as a result of storage has been demonstrated.
Constituents of the cotton bud: XII. The carotenoids in buds, seeds and other tissue
Authors: Thompson A. C. , Henson R. D. , Hedin P. A. , Minyard J. P. 
Published: November 2006

AbstractEleven carotenoid pigments were found in the bud, leaf, flower petal, seedling and seed of the cotton plant; nine were identified and quantitated. The most abundant carotenoids in the green tissue of the cotton plant were β‐carotene and lutein. Carotene hydrocarbons comprised 12% of the total carotenoids in the seed, 15% in the 1‐day‐old flower petal, 51% in the bud and 57% in green leaves. Only 5,8‐epoxy carotenoids were found in the flower petals and only 5,6‐epoxides in the other tissue but both were present in the seed. The colorless phytoene precursors to the carotenoids comprised from 20% to 38% of the total carotenoid pigment in the growing tissue of the plant.
Synthesis, purification and characterization of 7‐ketocholesterol and epimeric 7‐hydroxycholesterols
Authors: Chicoye E. , Powrie W. D. , Fennema O. 
Published: November 2006

AbstractVarious methods were assessed for the synthesis of 7‐ketocholesterol and epimeric 7‐hydroxycholesterols. Upon the oxidation of cholesteryl acetate with t‐butyl chromate, the resulting ketosterol acetate crystallized from methanol consisted of about 25% unoxidized cholesteryl acetate. After the sterol acetates were hydrolyzed in an aqueous K2CO3 medium, preparative TLC was used to fractionate the ketone from cholesterol.Of all the reducing agents employed, only LiAlH4 reduced completely the purified 7‐ketocholesterol to 7‐hydroxycholesterols without side reaction products and ketone contamination. Yields of 21.3 mg of 7α‐hydroxycholesterol and 72.6 mg of 7β‐hydroxycholesterol were obtained by preparative TLC of a diol mixture prepared by the LiAlH4‐reduction of 100 mg of 7‐ketocholesterol. To accomplish the preparative TLC separation of diol bands without overlapping, a double development of a chromatoplate with ethyl ether‐cyclohexane (90∶10, v/v) and ethyl ether was essential.Data on the melting point, optical rotation and infrared spectra, as well as TLC and GLC characteristics, were obtained for purified 7‐ketocholesterol and epimeric 7‐hydroxycholesterols.