Magnetic-field-induced charge redistribution in disordered graphene double quantum dots

We have studied the transport properties of a large graphene double quantum dot under the influence of a background disorder potential and a magnetic field. At low temperatures, the evolution of the charge-stability diagram as a function of the B field is investigated up to 10 T. Our results indicate that the charging energy of the quantum dot is reduced, and hence the effective size of the dot increases at a high magnetic field. We provide an explanation of our results using a tight-binding model, which describes the charge redistribution in a disordered graphene quantum dot via the formation of Landau levels and edge states. Our model suggests that the tunnel barriers separating different electron/hole puddles in a dot become transparent at high B fields, resulting in the charge delocalization and reduced charging energy observed experimentally.This work was financially supported by the European GRAND project (ICT/FET, Contract No. 215752) and EPSRC

Imaging ballistic carrier trajectories in graphene using scanning gate microscopy

We use scanning gate microscopy to map out the trajectories of ballistic carriers in high-mobility graphene encapsulated by hexagonal boron nitride and subject to a weak magnetic field. We employ a magnetic focusing geometry to image carriers that emerge ballistically from an injector, follow a cyclotron path due to the Lorentz force from an applied magnetic field, and land on an adjacent collector probe. The local electric field generated by the scanning tip in the vicinity of the carriers deflects their trajectories, modifying the proportion of carriers focused into the collector. By measuring the voltage at the collector while scanning the tip, we are able to obtain images with arcs that are consistent with the expected cyclotron motion. We also demonstrate that the tip can be used to redirect misaligned carriers back to the collector.This work was partly supported by the EPSRC; a Grant-in-Aid for Scientific Research on Innovative Areas “Science of Atomic Layers” from the Ministry of Education, Culture, Sports, Science and Technology (MEXT); the Project for Developing Innovation Systems of MEXT; the Grants-in-Aid for Scientific Research from the Japan Society for the Promotion of Science (JSPS); and the CREST, Japan Science and Technology Agency.This is the author accepted manuscript. The final version is available from AIP via http://dx.doi.org/10.1063/1.493747

Vortex detection and quantum transport in mesoscopic graphene Josephson-junction arrays

We investigate mesoscopic Josephson junction arrays created by patterning superconducting disks on monolayer graphene, concentrating on the high-$T/T_c$ regime of these devices and the phenomena which contribute to the superconducting glass state in diffusive arrays. We observe features in the magnetoconductance at rational fractions of flux quanta per array unit cell, which we attribute to the formation of flux-quantized vortices. The applied fields at which the features occur are well described by Ginzburg-Landau simulations that take into account the number of unit cells in the array. We find that the mean conductance and universal conductance fluctuations are both enhanced below the critical temperature and field of the superconductor, with greater enhancement away from the graphene Dirac point.This work was financially supported by the Engineering and Physical Sciences Research Council, and an NPL/EPSRC Joint Postdoctoral Partnership (RG61493).This is the accepted manuscript. The final version is available at http://journals.aps.org/prb/abstract/10.1103/PhysRevB.91.245418

The Emerging Scholarly Brain

It is now a commonplace observation that human society is becoming a coherent super-organism, and that the information infrastructure forms its emerging brain. Perhaps, as the underlying technologies are likely to become billions of times more powerful than those we have today, we could say that we are now building the lizard brain for the future organism.Comment: to appear in Future Professional Communication in Astronomy-II (FPCA-II) editors A. Heck and A. Accomazz

Оцінка оновлення основних засобів за рахунок позикових коштів

Оновлення основних засобів є актуальною проблемою сьогодення. Для багатьох підприємств кредити банків є чи не єдиним джерелом коштів на модернізацію виробничих потужностей. В даній статті нами були розглянуті можливості і перспективи приватних фірм для використання з цією метою позикових засобів, оцінений ступінь прозорості банківських установ, річні ставки за інвестиційними кредитами та інші умови їхнього надання.Modernizing of the basic assets is a topical problem of the present. For many business firms bank loans are may be the only source of funds for renewal of production facilities. In the article we have considered the opportunities and prospects for use of borrowed funds by private firms for this purpose, rated the degree of transparency of banking institutions, the annual rates of investment credits and other conditions of their granting

A new two-phase dimeticone pediculicide shows high efficacy in a comparative bioassay

Background: \ud Dimeticones kill head lice by physical means. Here we assessed in a comparative bioassay the ex vivo efficacy of "NYDA® sensitiv", a new two-phase dimeticone-based pediculicide similar to a product established on the market, but without fragrances.\ud \ud Methods:\ud We compared efficacy of the new product to a positive dimeticone control group, a sample of four other insecticidal and natural head lice products marketed in Germany, and an untreated control. In a bioassay, lice were exposed ex vivo to products and examined for activity for up to 24 hours, following a standard protocol.\ud \ud Results:\ud After 6 and 24 hours, 13.7 and 88.5% of untreated control lice did not show major vital signs. In contrast, no lice showed major vital signs 5 minutes after treatment with the new product or the control dimeticone group (NYDA®). This effect persisted at all observation points (100% efficacy). Efficacy of 0.5% permethrin (Infectopedicul®) ranged between 76 and 96% in evaluations between 5 min and 6 hours. All lice treated with a coconut-based compound (mosquito® Läuseshampoo) did not show major vital signs after 5 min, but mortality was only 58% after one hour. Pyrethrum extract (Goldgeist® forte) showed an efficacy of 22 - 52% between 5 min and 3 hours after treatment; after 6 hours, 76% of lice were judged dead. An oxyphthirine®-based compound (Liberalice DUO LP-PRO®) killed 22 - 54% of lice in the first 6 hours.\ud \ud Conclusions:\ud The two-phase dimeticone compound NYDA® sensitiv is highly efficacious. The removal of fragrances as compared to an established dimeticone product did not affect in vitro efficacy

An Antiviral Response Directed by PKR Phosphorylation of the RNA Helicase A

The double-stranded RNA-activated protein kinase R (PKR) is a key regulator of the innate immune response. Activation of PKR during viral infection culminates in phosphorylation of the α subunit of the eukaryotic translation initiation factor 2 (eIF2α) to inhibit protein translation. A broad range of regulatory functions has also been attributed to PKR. However, as few additional PKR substrates have been identified, the mechanisms remain unclear. Here, PKR is shown to interact with an essential RNA helicase, RHA. Moreover, RHA is identified as a substrate for PKR, with phosphorylation perturbing the association of the helicase with double-stranded RNA (dsRNA). Through this mechanism, PKR can modulate transcription, as revealed by its ability to prevent the capacity of RHA to catalyze transactivating response (TAR)–mediated type 1 human immunodeficiency virus (HIV-1) gene regulation. Consequently, HIV-1 virions packaged in cells also expressing the decoy RHA peptides subsequently had enhanced infectivity. The data demonstrate interplay between key components of dsRNA metabolism, both connecting RHA to an important component of innate immunity and delineating an unanticipated role for PKR in RNA metabolism

Independent Regulation of Reovirus Membrane Penetration and Apoptosis by the μ1 ϕ Domain

Apoptosis plays an important role in the pathogenesis of reovirus encephalitis. Reovirus outer-capsid protein μ1, which functions to penetrate host cell membranes during viral entry, is the primary regulator of apoptosis following reovirus infection. Ectopic expression of full-length and truncated forms of μ1 indicates that the μ1 ϕ domain is sufficient to elicit a cell death response. To evaluate the contribution of the μ1 ϕ domain to the induction of apoptosis following reovirus infection, ϕ mutant viruses were generated by reverse genetics and analyzed for the capacity to penetrate cell membranes and elicit apoptosis. We found that mutations in ϕ diminish reovirus membrane penetration efficiency by preventing conformational changes that lead to generation of key reovirus entry intermediates. Independent of effects on membrane penetration, amino acid substitutions in ϕ affect the apoptotic potential of reovirus, suggesting that ϕ initiates apoptosis subsequent to cytosolic delivery. In comparison to wild-type virus, apoptosis-defective ϕ mutant viruses display diminished neurovirulence following intracranial inoculation of newborn mice. These results indicate that the ϕ domain of μ1 plays an important regulatory role in reovirus-induced apoptosis and disease