343 research outputs found

    Why Do We Do Track Two?: Transnational Security Policy Networks and U.S. Nuclear Nonproliferation Policy

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    As globalization has accelerated, unofficial transnational (a.k.a. track-two) dialogues have proliferated. Do these networks matter? This study examines both their effects in the United States and, by focusing on nuclear nonproliferation, their potential to improve cooperative security as well as conflict resolution. Reviews of relevant theory, secondary literature, and primary materials produced by three case studies--the Council on Security Cooperation in the Asia Pacific (CSCAP), the Northeast Asian Cooperation Dialogue (NEACD), and the Program on New Approaches to Russian Security (PONARS)--supplemented and guided 67 original interviews to help answer the question: Have transnational security policy networks changed U.S. nuclear nonproliferation policies or the perceptions that shape them? These networks have improved intelligence and private as well as public diplomacy, enhancing the analytical capacity and soft power of their participants and interlocutors. They have strengthened otherwise weak ties across countries, areas of expertise, generations, and professions, particularly from inside government to nongovernmental experts, to provide blunter feedback and improve open-source intelligence analysis. These improvements are three-dimensional--delving deeper into overseas foreign policy elite, integrating across wider issues and regions, over longer periods of time--to help understand the implications of political changes, summits, and crises. Diplomatically, they have provided fora for nongovernmental experts and government officials in their private capacity to better understand and convey interests behind official talking points. Although U.S. policymakers will realistically rarely participate, they benefit from one-page or personal briefings by the most effective networks--those that have diverse members, integrate current or former government officials, and focus on ideas and information exchange. Although pressures exist to prove networks changed near-term policy decisions, the diversity that improves intelligence also impedes consensus on policy recommendations, which can be more effectively made by issue-specific cells derived from the network base. Ultimately, these networks empower their members and interlocutors with ideas and information, which enhances their soft power and builds their capacity to diagnose and agree on the root causes of contemporary threats, understand the political pressures shaping national responses to them, evaluate the merits of potential strategies to respond, and explore prospects for cooperative solutions

    Strongly truncated Dnaaf4 plays a conserved role in Drosophila ciliary dynein assembly as part of an R2TP-like co-chaperone complex with Dnaaf6

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    Axonemal dynein motors are large multi-subunit complexes that drive ciliary movement. Cytoplasmic assembly of these motor complexes involves several co-chaperones, some of which are related to the R2TP co-chaperone complex. Mutations of these genes in humans cause the motile ciliopathy, Primary Ciliary Dyskinesia (PCD), but their different roles are not completely known. Two such dynein (axonemal) assembly factors (DNAAFs) that are thought to function together in an R2TP-like complex are DNAAF4 (DYX1C1) and DNAAF6 (PIH1D3). Here we investigate the Drosophila homologues, CG14921/Dnaaf4 and CG5048/Dnaaf6. Surprisingly, Drosophila Dnaaf4 is truncated such that it completely lacks a TPR domain, which in human DNAAF4 is likely required to recruit HSP90. Despite this, we provide evidence that Drosophila Dnaaf4 and Dnaaf6 proteins can associate in an R2TP-like complex that has a conserved role in dynein assembly. Both are specifically expressed and required during the development of the two Drosophila cell types with motile cilia: mechanosensory chordotonal neurons and sperm. Flies that lack Dnaaf4 or Dnaaf6 genes are viable but with impaired chordotonal neuron function and lack motile sperm. We provide molecular evidence that Dnaaf4 and Dnaaf6 are required for assembly of outer dynein arms (ODAs) and a subset of inner dynein arms (IDAs)

    Inkjet Patterned Anodic Aluminum Oxide for Rear Metal Contacts of Silicon Solar Cells

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    AbstractLocal rear metal contacting through passivating dielectric layers has the ability to increase silicon solar cell efficiencies to over 20%. To-date most contact schemes have involved the formation of localised aluminium-alloyed regions through patterned AlOx or SiNx passivating layers. Recently electrochemically-formed anodic aluminium oxide (AAO) layers have been shown to enhance minority carrier lifetimes of phosphorus–diffused p-type CZ wafers when formed over an intervening layer of SiO2 or SiNx, suggesting that these layers may find applications as passivation layers for cells. We report here on the inkjet patterning of AAO layers formed over a thermally-grown thin oxide layer on p-type silicon surfaces. The process, which involves the inkjet printing of 50% (w/w) phosphoric acid, was used to form well-resolved arrays of holes with a diameter as small as 20-40μm in the dielectric stack. Alloying of aluminium, which was evaporated over the patterned dielectric stack, resulted in the formation of localised back surface field (BSF) regions having a thickness up to 8μm. Future work will focus on adapting this process for use in local rear metal contacting of silicon solar cells

    Studies of propene conversion over H-ZSM-5 demonstrate the importance of propene as an intermediate in methanol-to-hydrocarbons chemistry

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    Funding Information: Johnson Matthey plc. is thanked for supplying the ZSM-5 zeolite and for financial support through the provision of industrial CASE studentships in partnership with the EPSRC (APH (EP/P510506/1), AZ (EP/N509176/1)). Experiments at the ISIS Neutron and Muon Source were made possible by a beam time allocation from the Science and Technologies Facilities Council. 53 The resources and support provided by the UK Catalysis Hubviamembership of the UK Catalysis Hub consortium and funded by EPSRC grants EP/R026815/1 and EP/R026939/1 are gratefully acknowledged. This research has been performed with the use of facilities and equipment at the Research Complex at Harwell; the authors are grateful to the Research Complex for this access and support.Peer reviewedPublisher PD

    The Methyl Torsion in Unsaturated Compounds

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    The STFC Rutherford Appleton Laboratory is thanked for funding and access to neutron beam facilities. Computing resources (time on the SCARF compute cluster for the CASTEP calculations) was provided by STFC’s e-Science facility. Dr John Tomkinson (ISIS) is thanked for generously providing the INS spectra of the toluene isotopomers. A.Z. and A.P.H. would like to thank Johnson Matthey plc. For financial support through the provision of industrial CASE studentships in partnership with the EPSRC. The UK Catalysis Hub is kindly thanked for resources and support provided via our membership of the UK Catalysis Hub Consortium and funded by EPSRC grant: EP/R026939/1, EP/R026815/1, EP/R026645/1, EP/R027129/1 or EP/M013219/1(biocatalysis).Peer reviewedPublisher PD

    Investigation of the dynamics of 1-octene adsorption at 293 K in a ZSM-5 catalyst by inelastic and quasielastic neutron scattering

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    The properties of 1-octene adsorbed in zeolite ZSM-5 at 293 K are studied by means of inelastic and quasielastic neutron scattering (INS and QENS) in order to investigate interactions relevant to the zeolite solid acid catalysis of fluidised catalytic cracking reactions. The INS spectrum is compared to that recorded for the solid alkene and reveals significant changes of bonding on adsorption at ambient temperatures; the changes are attributed to the oligomerization of the adsorbed 1-octene to form a medium chain n-alkane or n-alkane cation. QENS analysis shows that these oligomers are immobilised within the zeolite pore structure but a temperature-dependant fraction is able to rotate around their long axis within the pore channels

    New Spectroscopic Insight into the Deactivation of a ZSM-5 Methanol-to-Hydrocarbons Catalyst

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    Funding Information: Johnson Matthey plc. is thanked for supplying the ZSM‐5 zeolite and for financial support through the provision of industrial CASE studentships in partnership with the EPSRC (APH (EP/P510506/1), AZ (EP/N509176/1)). Experiments at the ISIS Neutron and Muon Source were made possible by a beam time allocation from the Science and Technologies Facilities Council. The resources and support provided by the UK Catalysis Hub membership of the UK Catalysis Hub consortium and funded by EPSRC grants EP/R026815/1 and EP/R026939/1 are gratefully acknowledged. This research has been performed with the use of facilities and equipment at the Research Complex at Harwell; the authors are grateful to the Research Complex for this access and support. Dr Andrea Sauerwein and Dr Jonathan Bradley (Johnson Matthey) are thanked for their help in acquiring the Si and Al NMR spectra using the Bruker Avance Neo spectrometer.Peer reviewedPublisher PD

    Onset of propene oligomerization reactivity in ZSM-5 studied by inelastic neutron scattering spectroscopy

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    The techniques of quasi-elastic and inelastic neutron scattering (QENS and INS) are applied to investigate the oligomerization of propene over a ZSM-5 zeolite. Investigations are performed at low temperatures, allowing identification of the onset of the oligomerization reaction and observation of the low-energy spectral changes due to intermediate formation that are difficult to observe by optical methods. Oligomerization proceeds via formation of a hydrogen-bonded precursor by an interaction of the propene with an internal acid site followed by protonation and chain growth with protonation being the rate-limiting step. The use of quasi-elastic neutron scattering to observe changes in system mobility with temperature via the elastic window scan technique allows identification of the active temperature range where catalyst activity commences and permits targeting of the more time-consuming INS investigations to conditions of interest. From examination of the product’s spectrum, the structure of the resulting oligomer is deduced to be primarily linear
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