264 research outputs found
Towards cleaner production: a roadmap for predicting product end-of-life costs at early design concept
The primary objective of the research was to investigate how disposal costs were being incurred in the domain of defence electronic systems by the Original Equipment Manufacturer (OEM) and subsequently to ascertain a novel approach to prediction of their end-of-life (EOL) costs. It is intended that the OEM could utilise this method as part of a full lifecycle cost analysis at the conceptual design stage. The cost model would also serve as a useful guide to aid decision making at the conceptual design stage, so that it may lead to the design of a more sustainable product in terms of recycling, refurbishment or remanufacture with the consideration of financial impact. The novelty of this research is that it identifies the significance of disposal costs from the viewpoint of the OEM and provides a generic basis for evaluation of all the major EOL defence electronic systems. A roadmap has been proposed and developed to facilitate the prediction of disposal costs and this will be used to determine a satisfactory solution of whether the EOL parts of a defence electronic system are viable to be remanufactured, refurbished or recycled from an early stage of a design concept. A selected defence electronic system is used as a case study. Based on the findings, the proposed method offers a manageable and realistic solution so that the OEM can estimate the cost of potential EOL recovery processes at the concept design stag
Quantum spin pumping with adiabatically modulated magnetic barrier's
A quantum pump device involving magnetic barriers produced by the deposition
of ferro magnetic stripes on hetero-structure's is investigated. The device for
dc- transport does not provide spin-polarized currents, but in the adiabatic
regime, when one modulates two independent parameters of this device, spin-up
and spin-down electrons are driven in opposite directions, with the net result
being that a finite net spin current is transported with negligible charge
current. We also analyze our proposed device for inelastic-scattering and
spin-orbit scattering. Strong spin-orbit scattering and more so inelastic
scattering have a somewhat detrimental effect on spin/charge ratio especially
in the strong pumping regime. Further we show our pump to be almost noiseless,
implying an optimal quantum spin pump.Comment: 14 pages, 9 figures. Manuscript revised with additional new material
on spin-orbit scattering and inelastic scattering. Further new additions on
noiseless pumping and analytical results with distinction between weak and
strong pumping regimes. Accepted for publication in Physical Review
Magneto-transport in a quantum network: Evidence of a mesoscopic switch
We investigate magneto-transport properties of a shaped three-arm
mesoscopic ring where the upper and lower sub-rings are threaded by
Aharonov-Bohm fluxes and , respectively, within a
non-interacting electron picture. A discrete lattice model is used to describe
the quantum network in which two outer arms are subjected to binary alloy
lattices while the middle arm contains identical atomic sites. It is observed
that the presence of the middle arm provides localized states within the band
of extended regions and lead to the possibility of switching action from a high
conducting state to a low conducting one and vice versa. This behavior is
justified by studying persistent current in the network. Both the total current
and individual currents in three separate branches are computed by using
second-quantized formalism and our idea can be utilized to study magnetic
response in any complicated quantum network. The nature of localized
eigenstates are also investigated from probability amplitudes at different
sites of the quantum device.Comment: 7 pages, 9 figure
Formulae for zero-temperature conductance through a region with interaction
The zero-temperature linear response conductance through an interacting
mesoscopic region attached to noninteracting leads is investigated. We present
a set of formulae expressing the conductance in terms of the ground-state
energy or persistent currents in an auxiliary system, namely a ring threaded by
a magnetic flux and containing the correlated electron region. We first derive
the conductance formulae for the noninteracting case and then give arguments
why the formalism is also correct in the interacting case if the ground state
of a system exhibits Fermi liquid properties. We prove that in such systems,
the ground-state energy is a universal function of the magnetic flux, where the
conductance is the only parameter. The method is tested by comparing its
predictions with exact results and results of other methods for problems such
as the transport through single and double quantum dots containing interacting
electrons. The comparisons show an excellent quantitative agreement.Comment: 18 pages, 18 figures; to appear in Phys. Rev.
Explaining the Higgs Decays at the LHC with an Extended Electroweak Model
We show that the recent discovery of a new boson at the LHC, which we assume
to be a Higgs boson, and the observed enhancement in its diphoton decays
compared to the SM prediction, can be explained by a new doublet of charged
vector bosons from an extended electroweak gauge sector model with
SU(3)_C\otimesSU(3)_L\otimesU(1)_X symmetry. Our results show a good
agreement between our theoretical expected sensitivity to a 126--125 GeV Higgs
boson and the experimental significance observed in the diphoton channel at the
8 TeV LHC. Effects of an invisible decay channel for the Higgs boson are also
taken into account, in order to anticipate a possible confirmation of deficits
in the branching ratios into , , bottom quarks, and tau leptons.Comment: 16 pages, 5 figure
Short-term prognosis of breakthrough venous thromboembolism in anticoagulated patients
Background: Evidence for guideline recommendations for the treatment of venous thromboembolism (VTE) during anticoagulant therapy is scarce. We aimed to observe and to describe the management of VTE occurring during anticoagulant therapy. Methods: This prospective multi-center, observational study included patients with objectively confirmed VTE during anticoagulant therapy (breakthrough event), with a follow-up of 3 months, after the breakthrough event. Results: We registered 121 patients with a breakthrough event, with a mean age of 56 years (range, 19 to 90); 61 were male (50%). Fifty-eight patients (48%) had an active malignancy. At the time of the breakthrough event, 57 patients (47%) were treated with a vitamin K antagonist (VKA), 53 patients (44%) with low-molecular-weight heparin (LMWH) and 11 patients (9%) with direct oral anticoagulants, unfractionated heparin, or VKA plu
Cyclin E overexpression sensitizes triple negative breast cancer to Wee1 kinase Inhibition
Purpose: Poor prognosis in triple-negative breast cancer (TNBC) is due to an aggressive phenotype and lack of biomarker-driven targeted therapies. Overexpression of cyclin E and phosphorylated-CDK2 are correlated with poor survival in TNBC patients, and the absence of CDK2 desensitizes cells to inhibition of Wee1 kinase, a key cell cycle regulator. We hypothesize that cyclin E expression can predict response to therapies, which include the Wee1 kinase inhibitor, AZD1775. Experimental Design: Mono and combination therapies with AZD1775 were evaluated in TNBC cell lines and multiple patient derived xenograft (PDX) models with different cyclin E expression profiles. The mechanism(s) of cyclin E-mediated replicative stress were investigated following cyclin E induction or CRISPR/Cas9 knockout by a number of assays in multiple cells lines. Results: Cyclin E overexpression (1) is enriched in TNBCs with high recurrence rates, (2) sensitizes TNBC cell lines and PDX models to AZD1775, (3) leads to CDK2-dependent activation of DNA replication stress pathways and (4) increases Wee1 kinase activity. Moreover, treatment of cells with either CDK2 inhibitors or carboplatin leads to transient transcriptional induction of cyclin E (in cyclin E-low tumors) and result in DNA replicative stress. Such drug mediated cyclin E induction in TNBC cells and PDX models sensitizes them to AZD1775 in a sequential treatment combination strategy. Conclusions: Cyclin E is a potential biomarker of response (1) for AZD1775 as monotherapy in cyclin E high TNBC tumors and (2) for sequential combination therapy with CDK2 inhibitor or carboplatin followed by AZD1775 in cyclin E low TNBC tumors
Neutral Higgs boson pair production via collision in the minimal supersymmetric standard model at linear colliders
We investigate in detail the fusion production mechanisms of
two neutral Higgs bosons (, , and ) within
the framework of the mSUGRA-inspired minimal supersymmetric standard
model(MSSM) at an linear colliders, which provide a probe of the
trilinear Higgs self-couplings. We calculate the dependence of the production
rates on Higgs boson masses, the ratio of the vacuum expectation values and the CMS energy . We find that the cross section for the
production at LC can reach , while the cross section of
production is only under our parameters.Comment: Accepted by Phys. Rev.
A Solvable Regime of Disorder and Interactions in Ballistic Nanostructures, Part I: Consequences for Coulomb Blockade
We provide a framework for analyzing the problem of interacting electrons in
a ballistic quantum dot with chaotic boundary conditions within an energy
(the Thouless energy) of the Fermi energy. Within this window we show that the
interactions can be characterized by Landau Fermi liquid parameters. When ,
the dimensionless conductance of the dot, is large, we find that the disordered
interacting problem can be solved in a saddle-point approximation which becomes
exact as (as in a large-N theory). The infinite theory shows a
transition to a strong-coupling phase characterized by the same order parameter
as in the Pomeranchuk transition in clean systems (a spontaneous
interaction-induced Fermi surface distortion), but smeared and pinned by
disorder. At finite , the two phases and critical point evolve into three
regimes in the plane -- weak- and strong-coupling regimes separated
by crossover lines from a quantum-critical regime controlled by the quantum
critical point. In the strong-coupling and quantum-critical regions, the
quasiparticle acquires a width of the same order as the level spacing
within a few 's of the Fermi energy due to coupling to collective
excitations. In the strong coupling regime if is odd, the dot will (if
isolated) cross over from the orthogonal to unitary ensemble for an
exponentially small external flux, or will (if strongly coupled to leads) break
time-reversal symmetry spontaneously.Comment: 33 pages, 14 figures. Very minor changes. We have clarified that we
are treating charge-channel instabilities in spinful systems, leaving
spin-channel instabilities for future work. No substantive results are
change
Quel rôle peut-on imputer aux banques à charte canadiennes dans la transmission des chocs monétaires des années quatre-vingt?
Cette recherche s’inscrit dans la foulée de nombreux travaux entrepris suite aux publications de Bernanke et Blinder (1988, 1992) ayant remis à l’avant-plan le rôle joué par le système bancaire dans la transmission de la politique monétaire. Nous proposons d’examiner la dynamique inhérente à certains postes du bilan des banques à charte canadiennes suite aux mouvement des principaux taux d’intérêt, habituellement jugés révélateurs des conditions monétaires du moment. Pour ce faire, nous avons recours à un modèle VAR hebdomadaire comportant à la fois, des éléments de l’actif et du passif des banques ainsi que les taux de rendement associés à divers instruments financiers. Cependant, dans le but de bien encadrer cette analyse, nous développons un modèle formel du comportement d’une banque où les seuls changements aux postes de son bilan suite aux mouvements de taux d’intérêt sont dictés par des ajustements de portefeuille visant à tirer avantage des écarts se creusant entre ceux-ci. Ce modèle théorique est soumis aux variations de taux d’intérêt issues du modèle empirique VAR. Les mouvements observés aux postes du bilan de cette banque « témoin » fournissent un guide utile permettant d’interpréter de façon éclairée les résultats empiriques obtenus. À cet égard, l’exercice proposé montre qu’il est possible d’établir un parallèle assez étroit entre l’évolution des postes du bilan de la banque hypothétique et celle captée par le modèle VAR et ainsi apporte un certain support à l’approche traditionnelle sur le rôle joué par les banques dans la transmission des chocs monétaires.This paper can be seen as a contribution to a growing literature initiated by Bernanke and Blinder (1988, 1992) which have examined the role played by the banking system in the transmission of monetary policy. We propose to study the dynamic behaviour of the balance sheet of Canadian chartered banks following a shock to some key interest rates which are good indicators of the prevailing monetary conditions. More specifically, we estimate a weekly VAR model which comprises key asset and liabilities elements as well as rates of return on major financial instruments. However, to guide this empirical inquiry, we set up a model of a representative bank which adjusts its balance sheet elements according to the interest rate spreads arising in the financial markets. This theoretical model is then subjected to the same interest rate shocks than those imposed on the VAR model: the adjustments observed in this laboratory will prove quite useful to assess the significance of the empirical results uncovered by the VAR model. Overall, we find that both approaches give rise to quite similar dynamic responses which tends to support the traditional role of the banking sector in the transmission of monetary policy
- …