bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nonclassical correlations in superconducting circuits
Authors: Migliore Rosanna , Scala Matteo , Guccione Marina , Sánchez‐Soto Luis L. , Messina Antonino 
Published: April 2009

AbstractA key step on the road map to solid‐state quantum information processing (and to a deeper understanding of many counterintuitive aspects of quantum mechanics) is the generation and manipulation of nonclassical correlations between different quantum systems. Within this framework, we analyze the possibility of generating maximally entangled states in a system of two superconducting flux qubits, as well as the effectof their own environments on the entanglement dynamics. The analysis reported here confirms that the phenomena of sudden birth and sudden death of the entanglement do not depend on the particular measure of the entanglement adopted (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Kondo effect in oscillating molecules
Authors: Mravlje Jernej , Ramsak Anton 
Published: April 2009

AbstractWe consider electronic transport through break‐junctions bridged by a single molecule in the Kondo regime. We describe the system by a two‐channel Anderson model. We take the tunneling matrix elements to depend on the position of the molecule. It is shown, that if the modulation of the tunneling by displacement is large, the potential confining the molecule to the central position between the leads is softened and the position of the molecule is increasingly susceptible to external perturbations that break the inversion symmetry. In this regime, the molecule is attracted to one of the leads and as a consequence the conductance is small. We argue on semi‐classical grounds why the softening occurs and corroborate our findings by numerical examples obtained by Wilson's numerical renormalization group and Schönhammer–Gunnarsson's variational method (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Addressing climate change democratically. Multi‐level governance, transnational networks and governmental structures
Authors: Lidskog Rolf , Elander Ingemar 
Published: April 2009

AbstractThe purpose of the article is to discuss the democratic implications of climate change and whether or not it is possible to harmonize basic democratic values with the challenges raised by global warming. Highlighting three central democratic mechanisms it is argued that even if participation and deliberation are crucial for addressing the challenge of climate change this must be done within a system of democratic representation. To become both efficient and democratic, climate governance has to include different spheres and levels of authority. As there is no blueprint for a new institutional order of this kind we have to build upon and better utilize the patchwork of multi‐level governance at hand. The growing number of trans‐national networks, including a great variety of coalitions between actors from formal as well as informal institutions, has a great potential as an arena for deliberation of the challenge of climate change. Copyright © 2009 John Wiley & Sons, Ltd and ERP Environment.
A socio‐metabolic transition towards sustainability? Challenges for another Great Transformation
Authors: Haberl Helmut , Fischer‐Kowalski Marina , Krausmann Fridolin , Martinez‐Alier Joan , Winiwarter Verena 
Published: April 2009

AbstractOver the last two million years, humans have colonized almost the entire biosphere on Earth, thereby creating socio‐ecological systems in which fundamental patterns and processes are co‐regulated by socio‐economic and ecological processes. We postulate that the evolution of coupled socio‐ecological systems can be characterized by a sequence of relatively stable configurations, here denoted as ‘socio‐metabolic regimes’, and comparatively rapid transitions between such regimes. We discern three fundamentally different socio‐metabolic regimes: hunter‐gatherers, agrarian societies and industrial society. Transitions between these regimes fundamentally change socio‐ecological interactions, whereas changes and variations within each regime are gradual. Two‐thirds of the world population are currently within a rapid transition from the agrarian to the industrial regime. Many current global sustainability problems are a direct consequence of this transition. The central hypothesis discussed in this article is that industrial society is at least as different from a future sustainable society as it is from the agrarian regime. The challenge of sustainability is, therefore, a fundamental re‐orientation of society and the economy, not the implementation of some technical fixes. Based on empirical data for global resource use (material and energy flows, land use), this essay questions the notion that the promotion of eco‐efficiency is sufficient for achieving sustainability, and outlines the reasons why a transition to a new socio‐metabolic regime is now required. Copyright © 2009 John Wiley & Sons, Ltd and ERP Environment.
Complementarity, capabilities, and the boundaries of the firm: the impact of within‐firm and interfirm expertise on concurrent sourcing of complementary components
Authors: Parmigiani Anne , Mitchell Will 
Published: April 2009

AbstractTheories of the firm raise conflicting arguments about how complementarities between two or more components affect firms' knowledge and production boundaries. Traditional arguments in the boundaries of the firm literature suggest that firms will tend to produce sets of complementary components internally, while more recent modularity studies argue that firms can outsource to gain flexibility. We resolve these views by examining concurrent sourcing, which arises when firms both make and buy the same components. We argue that concurrent sourcing of complementary components becomes more common in two cases: when firms have relevant knowledge about the components in conjunction with suppliers (interfirm expertise) and, perhaps more surprisingly, within the firm (within‐firm shared expertise). The results suggest that firms often need to make in order to know, but can partially outsource if they possess sufficient expertise. Copyright © 2009 John Wiley & Sons, Ltd.
Control, collaboration, and productivity in international joint ventures: theory and evidence
Authors: Li Jing , Zhou Changhui , Zajac Edward J. 
Published: April 2009

AbstractThis study analyzes the following unresolved questions: In international joint ventures (IJVs) in a developing country, how could different IJV structures address control and collaboration considerations, and what is the likely effect of such different structures on IJV productivity? Theoretically, we suggest that the ambiguity surrounding these questions reflects the tendency of researchers to view control and collaboration as opposing objectives, studying one or the other; in contrast, we provide a more integrative perspective that blends the two objectives, focusing on common underlying issues relating to enhancing partner commitment, ensuring partner knowledge contributions, and reducing partner risks. We address the most salient design consideration for IJV partners, that is, IJV ownership structure, to posit that joint consideration of the control benefit of a higher foreign ownership level in IJVs and the collaboration benefit of a more balanced IJV ownership structure results in an expected inverted U‐curve relationship between foreign ownership and IJV productivity. Additionally, we posit and test how three environmental contingencies, by affecting the need for control and collaboration in IJVs, would further influence the specific shape of the inverted U‐curve relationship. We find strong support for our theory using an extensive longitudinal dataset of over 5,000 IJVs in China from 1999–2003. We discuss the value of our approach and findings both for researchers and for IJV partners seeking the dual benefits of control and collaboration. Copyright © 2009 John Wiley & Sons, Ltd.
Thermally Activated Photoluminescence in Lead Selenide Colloidal Quantum Dots
Authors: Kigel Ariel , Brumer Maya , Maikov Georgy I. , Sashchiuk Aldona , Lifshitz Efrat 
Published: April 2009

AbstractThe thermal activation processes in PbSe colloidal quantum dots and their influence on the ground‐state exciton emission are discussed. Activation of a dark exciton occurs at 1.4–7 K, assisted by an acoustic phonon coupling. Activation of a bright exciton occurs at 100–200 K, which appears as a sudden change in the photoluminescence band intensity, energy, and full width at half maximum. This activation overcomes the dark–bright‐state splitting, when the activation temperature increases with the decrease of the dots' size. The dark exciton lifetime is found to be ≈6–12 µs at 1.4 K, while the bright exciton lifetime at 300 K evaluated as 450 ns varies slightly with the change in the size of the dots. In addition, the emission quantum yield of these dots, measured at a variety of temperatures when dissolved in various solvents, reveals information about the influence of the environment on the recombination processes.
Activin A Is Essential for Neurogenesis Following Neurodegeneration
Authors: Abdipranoto-Cowley Andrea , Park Jin Sung , Croucher David , Daniel James , Henshall Susan , Galbraith Sally , Mervin Kyle , Vissel Bryce 
Published: April 2009

Abstract
It has long been proposed that excitotoxicity contributes to nerve cell death in neurodegenerative diseases. Activin A, a member of the transforming growth factor-β superfamily, is expressed by neurons following excitotoxicity. We show for the first time that this activin A expression is essential for neurogenesis to proceed following neurodegeneration. We found that intraventricular infusion of activin A increased the number of newborn neurons in the dentate gyrus, CA3, and CA1 layers of the normal adult hippocampus and also, following lipopolysaccharide administration, had a potent inhibitory effect on gliosis in vivo and on microglial proliferation in vivo and in vitro. Consistent with the role of activin A in regulating central nervous system inflammation and neurogenesis, intraventricular infusion of follistatin, an activin A antagonist, profoundly impaired neurogenesis and increased the number of microglia and reactive astrocytes following onset of kainic acid-induced neurodegeneration. These results show that inhibiting endogenous activin A is permissive for a potent underlying inflammatory response to neurodegeneration. We demonstrate that the anti-inflammatory actions of activin A account for its neurogenic effects following neurodegeneration because co-administration of nonsteroidal anti-inflammatory drugs reversed follistatin's inhibitory effects on neurogenesis in vivo. Our work indicates that activin A, perhaps working in conjunction with other transforming growth factor-β superfamily molecules, is essential for neurogenesis in the adult central nervous system following excitotoxic neurodegeneration and suggests that neurons can regulate regeneration by suppressing the inflammatory response, a finding with implications for understanding and treating acute and chronic neurodegenerative diseases.
Disclosure of potential conflicts of interest is found at the end of this article.
Maintenance of Undifferentiated State and Self-Renewal of Embryonic Neural Stem Cells by Polycomb Protein Ring1B
Authors: Román-Trufero Mónica , Méndez-Gómez Héctor R. , Pérez Claudia , Hijikata Atsushi , Fujimura Yu-ichi , Endo Takaho , Koseki Haruhiko , Vicario-Abejón Carlos , Vidal Miguel 
Published: April 2009

AbstractCell lineages generated during development and tissue maintenance are derived from self-renewing stem cells by differentiation of their committed progeny. Recent studies suggest that epigenetic mechanisms, and in particular the Polycomb group (PcG) of genes, play important roles in controlling stem cell self-renewal. Here, we address PcG regulation of stem cell self-renewal and differentiation through inactivation of Ring1B, a histone H2A E3 monoubiquitin ligase, in embryonic neural stem cells (NSCs) from the olfactory bulb of a conditional mouse mutant line. We show that neural stem/progenitor cell proliferation in vivo and in neurosphere assays is impaired, lacking Ring1B, and their self-renewal and multipotential abilities, assessed as sphere formation and differentiation from single cells, are severely affected. We also observed unscheduled neuronal, but not glial, differentiation of mutant stem/progenitor cells under proliferating conditions, an alteration enhanced in cells also lacking Ring1A, the Ring1B paralog, some of which turned into morphologically identifiable neurons. mRNA analysis of mutant cells showed upregulation of some neuronal differentiation–related transcription factors and the cell proliferation inhibitor Cdkn1a/p21, as well as downregulation of effectors of the Notch signaling pathway, a known inhibitor of neuronal differentiation of stem/progenitor cells. In addition, differentiation studies of Ring1B-deficient progenitors showed decreased oligodendrocyte formation in vitro and enhanced neurogenesis and reduced gliogenesis in vivo. These data suggest a role for Ring1B in maintenance of the undifferentiated state of embryonic neural stem/progenitor cells. They also suggest that Ring1B may modulate the differentiation potential of NSCs to neurons and glia.Disclosure of potential conflicts of interest is found at the end of this article.
ES Cell Cycle Progression and Differentiation Require the Action of the Histone Methyltransferase Dot1L
Authors: Barry Evan R. , Krueger Winfried , Jakuba Caroline M. , Veilleux Eric , Ambrosi Dominic J. , Nelson Craig E. , Rasmussen Theodore P. 
Published: April 2009

Abstract
Mouse embryonic stem cells (ESCs) proliferate with rapid cell cycle kinetics but without loss of pluripotency. The histone methyltransferase Dot1L is responsible for methylation of histone H3 at lysine 79 (H3K79me). We investigated whether ESCs require Dot1L for proper stem cell behavior. ESCs deficient in Dot1L tolerate a nearly complete loss of H3K79 methylation without a substantial impact on proliferation or morphology. However, shortly after differentiation is induced, Dot1L-deficient cells cease proliferating and arrest in G2/M-phase of the cell cycle, with increased levels of aneuploidy. In addition, many aberrant mitotic spindles occur in Dot1L-deficient cells. Surprisingly, these mitotic and cell cycle defects fail to trigger apoptosis, indicating that mouse ESCs lack stringent cell cycle checkpoint control during initial stages of differentiation. Transcriptome analysis indicates that Dot1L deficiency causes the misregulation of a select set of genes, including many with known roles in cell cycle control and cellular proliferation as well as markers of endoderm differentiation. The data indicate a requirement for Dot1L function for early stages of ESC differentiation where Dot1L is necessary for faithful execution of mitosis and proper transcription of many genes throughout the genome.
Disclosure of potential conflicts of interest is found at the end of this article.
Modelling the response function of energy dispersive X‐ray spectrometers with silicon detectors
Authors: Scholze F. , Procop M. 
Published: April 2009

AbstractA new, analytical description of the physical processes determining the spectral response of an energy dispersive X‐ray spectrometer with a silicon detector (Si(Li) or silicon drift detector (SDD)) is presented. The model considers the detector statistical noise, the electronic noise, the incomplete charge collection (ICC) that gives rise to the peak tailing, the escape effect, the fluorescence of the front contact or the dead layer and hot photoelectrons that cause the shelf. Only five free parameters are necessary to model the response function: the electronic noise, three parameters describing the shape of the charge collection efficiency beneath the front contact and the thickness of the detector front layer. Once the five parameters are adjusted to have agreement between a measured and a calculated response function, the response function can be calculated for any other photon energy in the range from 0.1 keV to 30 keV.The algorithm is implemented in IDL and MATLAB and is available also as MATLAB stand‐alone program. It enables the determination of the optimum parameter set by fitting a calculated response function to a measured one for monochromatic radiation. A (m,n)‐type matrix can be calculated whereby m represents the number of channels for the response function and n the number of photon energies in the selected range. The matrix can be used to convolute a calculated spectrum for comparison with a measured one.The calculated response functions are in agreement with the pulse height distributions measured with monochromatic synchrotron radiation in the energy range from 0.1 keV to 10 keV for three spectrometers with detector crystals different in construction. It is shown that the improved description of the detector response enables the detection of minor components of characteristic lines in fluorescence spectra, which have been attributed earlier to the detector. Copyright © 2009 John Wiley & Sons, Ltd.
Hexakis(cyanogen)zinc(II) Hexafluoridoarsenate – Synthesis, Structure and a Raman Spectroscopic Study of an Octahedral Homoleptic Cyanogen Complex
Authors: Beck Johannes , Zink Marcus 
Published: April 2009

Abstract[Zn(NCCN)6][AsF6]2 (1) was prepared either by dissolving [Zn(SO2)6](Te6)[AsF6]6 in a SO2/(CN)2 mixture, or by the reaction of [Zn(AsF6)2(SO2)x] dissolved in liquid SO2 and cyanogen. The respective nickel complex [Ni(NCCN)x][AsF6]2 (2) was obtained from [Ni(AsF6)2(SO2)x] or from [Ni(SO2)6](Te6)[AsF6]6. Both, 1 and 2 were obtained in quantitative yield. Compound 1 crystallizes isopointally to [Ni(NCCH3)6][SbF6]2 (Leban 1987), [Fe(NCCH3)6][SbF6]2 (Brennessel 2001), [Zn(NCCH3)6][AsF6]2 (Passmore 2006) and contains only slightly distorted octahedral [Zn(NCCN)6]2+ cations and [AsF6]– anions. The linearity of the NC–CN molecules is preserved in the complexes. Raman spectra of 1 and 2 are presented and compared with the literature data. The almost identical spectra allow for the assumption that the nickel complex (2) is isostructural to the zinc complex (1).
Study of Natural Halloysite from the Dragon Mine, Utah (USA)
Authors: García Francisco J. , García Rodríguez Sergio , Kalytta Andreas , Reller Armin 
Published: April 2009

AbstractA natural sample from the Dragon Mine, Tintic District, Silver City, Utah (USA), has been characterised. It contains a mixture of halloysite and alunite. The former shows the characteristic tubularly shaped particles while the latter is found to crystallise in platy particles. The crystal structure of halloysite is stable up to 400–450 °C and before decomposition some crystallisation is observed. Amorphisation is observed with further increasing the annealing temperature. However, the halloysite particles conserve the original morphology (tubes) up to 900 °C. The size distribution of the tubes is found to be quite broad. This is argued to be responsible for the poor measured surface area.
Synthesis of Chloroalkoxy eicosanoic and docosanoic acids from meadowfoam fatty acids by oxidation with aqueous sodium hypochlorite
Authors: Mund Melissa S. , Isbell Terry A. 
Published: April 2009

AbstractChloroalkoxy substituted C20 and C22 fatty acids can be synthesized from the unsaturated fatty acids in meadow‐foam oil by reaction of the fatty acids with primary or secondary alcohols and an aqueous sodium hypochlorite solution (commercial bleach). The reactions are conducted at room temperature for 3 h. Chlorohydroxy fatty acid derivatives are formed as by‐products owing to the presence of water in the reaction mixture. Chlorinated δ‐lactones are also produced by direct reaction of sodium hypochlorite with the Δ5 unsaturated fatty acids present in meadowfoam or by ring closure of the 6‐chloro‐5‐hydroxy fatty acids. The product yield of chloroalkoxy fatty acids is dependent on the nature and volume of the alcohol used in the reaction, as well as the concentration and pH of the sodium hypochlorite solution. Primary alcohols such as methanol and butanol produce maximal yields (50–60%) of chloroalkoxy fatty acids whereas the secondary alcohol 2‐propanol gives a 30% yield. Chloroalkoxy fatty acid yields can be increased to 75–80% by elimination of water from the reaction mixture through a procedure that partitions sodium hypochlorite from water into hexane/ethyl acetate mixtures. All of the reaction products were fully characterized using nuclear magnetic resonance and gas chromatography‐mass spectrometry.
EXISTENCE AND STABILITY OF PERIODIC SOLUTIONS OF A RAYLEIGH TYPE EQUATION
Authors: WANG YONG , DAI XIAN-ZHI 
Published: April 2009

AbstractIn this work, we shall be concerned with the following forced Rayleigh type equation: Under certain assumptions, some criteria for guaranteeing the existence, uniqueness and asymptotic stability (in the Lyapunov sense) of periodic solutions of this equation are presented by applying the Manásevich–Mawhin continuation theorem, Floquet theory, Lyapunov stability theory and some analysis techniques. Moreover, an example is provided to demonstrate the applications of our results.
Subject-verb order in spoken Arabic: Morpholexical and event-based factors
Authors: Owens Jonathan , Dodsworth Robin , Rockwood Trent 
Published: April 2009

AbstractThis article explores the relationship between the global functions of variable subject-verb order and morpholexical class of subjects in the spoken Arabic of the Arabian peninsula. Using corpus-based methods, it is shown that lexical class—pronoun, pronominal, noun—definiteness, and the discourse-defined lexical specificity of a noun all correlate significantly with subject-verb or verb-subject word order. The global function of the two orders is explored using an array of measures to show that verb-subject order prototypically presents events, while subject-verb signals available referentiality. Using the quantitatively based study of Anthony Naro and Sebastiao Votre ([1999]. Discourse motivations for linguistic regularities: Verb/subject order in spoken Brazilian Portuguese.Probus11:75–100.) on Brazilian Portuguese as a point of comparison, a typological framework is developed for understanding languages with variable subject-verb order.
Universal and dialect-specific pathways of acquisition: Caregivers, children, and t/d deletion
Authors: Smith Jennifer , Durham Mercedes , Fortune Liane 
Published: April 2009

AbstractT/d deletion is one of the most widely studied variables in sociolinguistic research, and findings demonstrate universal morphological and phonological constraints across a range of dialects. Research into the acquisition of this variable suggests that articulatory constraints are learned first, followed by grammatical, and finally stylistic and social constraints. Dialect-specific constraints are also found, implicating the caregiver in the process of acquisition. In this article, we contribute to this research on the acquisition of t/d through the examination of the speech of preschool children in interaction with their primary caregivers in a community in Scotland. Our results mirror previous results on how and when particular constraints are acquired, providing further evidence for universal order of acquisition of this form. We also demonstrate dialect-specific constraints on use that can be mapped directly to caregiver speech. This provides additional evidence on how variable forms are transmitted from parent to child in these early stages.