1,509 research outputs found

    Effect of varying dimension on critical currents in thin indium films

    Get PDF
    http://www.archive.org/details/effectofvaryingd00wrigU.S. Army (USA) authorU.S. Navy (USN) autho

    Beating patterns of filaments in viscoelastic fluids

    Full text link
    Many swimming microorganisms, such as bacteria and sperm, use flexible flagella to move through viscoelastic media in their natural environments. In this paper we address the effects a viscoelastic fluid has on the motion and beating patterns of elastic filaments. We treat both a passive filament which is actuated at one end, and an active filament with bending forces arising from internal motors distributed along its length. We describe how viscoelasticity modifies the hydrodynamic forces exerted on the filaments, and how these modified forces affect the beating patterns. We show how high viscosity of purely viscous or viscoelastic solutions can lead to the experimentally observed beating patterns of sperm flagella, in which motion is concentrated at the distal end of the flagella

    NuSTAR reveals the hidden nature of SS433

    Get PDF
    SS433 is the only Galactic binary system known to accrete at highly super-critical rates, analogous to tidal disruption events, and needed to explain the mass of some high redshift quasars. Probing the inner regions of SS433 in the X-rays is crucial to understanding this system, and super-critical accretion in general, but has not yet been possible due to obscuration. NuSTAR observed SS433 in the hard X-ray band across multiple phases of its super-orbital precession period. Spectral-timing tools have allowed us to confirm that the hard X-ray emission from the inner regions is scattered towards us by the walls of the wind-cone. By comparing to numerical models, we determine an intrinsic X-ray luminosity of >= 3x10^37 erg/s and that, if viewed face on, the apparent luminosity would be > 1x10^39 erg/s, confirming its long-suspected nature as an ultraluminous X-ray source (ULX). A lag due to absorption by Fe XXV/XXVI in outflowing material travelling at least 0.14-0.29c matches absorption lines seen in ULXs and - in future - will allow us to map a super-critical outflow for the first time.Comment: 24 pages, 8 figures, submitted for publicatio

    The Effect of a Brief Salivary α-Amylase Exposure During Chewing on Subsequent in Vitro Starch Digestion Curve Profiles

    Get PDF
    There is inconsistency between current in vitro digestion methods with regard to accommodation of a (salivary) α-amylase exposure during the oral phase. The effect of a salivary α-amylase pre-exposure on subsequent in vitro starch digestion curve profiles for various foods was investigated. Foods were chewed, expectorated and the boluses left to rest for 0–15 min. During pancreatic digestion, aliquots were taken and hydrolysis curves constructed for comparison against those of the same foods comminuted with a manually-operated chopper, hence spared exposure to saliva. Hydrolysate aliquots taken at T0 (time zero) of the digestion of chewed samples contained higher levels of glucose and dextrins compared with chopped samples. Pancreatin activity immediately overwhelmed differences in sugar released due to salivary amylase activity. Within 10 min no differences were detectable between hydrolysis curves for chewed and chopped foods. Salivary amylase pretreatment does not contribute to the robustness or relative accuracy of in vitro methods

    Measuring the capability to raise revenue process and output dimensions and their application to the Zambia revenue authority

    Get PDF
    The worldwide diffusion of the good governance agenda and new public management has triggered a renewed focus on state capability and, more specifically, on the capability to raise revenue in developing countries. However, the analytical tools for a comprehensive understanding of the capability to raise revenue remain underdeveloped. This article aims at filling this gap and presents a model consisting of the three process dimensions ‘information collection and processing’, ‘merit orientation’ and ‘administrative accountability’. ‘Revenue performance’ constitutes the fourth capability dimension which assesses tax administration’s output. This model is applied to the case of the Zambia Revenue Authority. The dimensions prove to be valuable not only for assessing the how much but also the how of collecting taxes. They can be a useful tool for future comparative analyses of tax administrations’ capabilities in developing countries.Die weltweite Verbreitung der Good-Governance- und New-Public-Management-Konzepte hat zu einer zunehmenden Konzentration auf staatliche Leistungsfähigkeit und, im Besonderen, auf die Leistungsfähigkeit der Steuererhebung in Entwicklungsländern geführt. Allerdings bleiben die analytischen Werkzeuge für ein umfassendes Verständnis von Leistungsfähigkeit unterentwickelt. Dieser Artikel stellt hierfür ein Modell vor, das die drei Prozess-Dimensionen „Sammeln und Verarbeiten von Informationen“, „Leistungsorientierung der Mitarbeiter“ und „Verantwortlichkeit der Verwaltung“ beinhaltet. „Einnahmeperformanz“ ist die vierte Dimension und erfasst den Output der Steuerverwaltung. Das mehrdimensionale Modell wird für die Analyse der Leistungsfähigkeit der Steuerbehörde Zambias (Zambia Revenue Authority) genutzt. Es erweist sich nicht nur für die Untersuchung des Wieviel, sondern auch des Wie des Erhebens von Steuern als wertvoll. Die vier Dimensionen können in Zukunft zur umfassenden und vergleichenden Analyse der Leistungsfähigkeit verschiedener Steuerverwaltungen in Entwicklungsländern genutzt werden

    Deep Broadband Observations of the Distant Gamma-ray Blazar PKS 1424+240

    Full text link
    We present deep VERITAS observations of the blazar PKS 1424+240, along with contemporaneous Fermi Large Area Telescope, Swift X-ray Telescope and Swift UV Optical Telescope data between 2009 February 19 and 2013 June 8. This blazar resides at a redshift of z0.6035z\ge0.6035, displaying a significantly attenuated gamma-ray flux above 100 GeV due to photon absorption via pair-production with the extragalactic background light. We present more than 100 hours of VERITAS observations from three years, a multiwavelength light curve and the contemporaneous spectral energy distributions. The source shows a higher flux of (2.1±0.3\pm0.3)×107\times10^{-7} ph m2^{-2}s1^{-1} above 120 GeV in 2009 and 2011 as compared to the flux measured in 2013, corresponding to (1.02±0.08\pm0.08)×107\times10^{-7} ph m2^{-2}s1^{-1} above 120 GeV. The measured differential very high energy (VHE; E100E\ge100 GeV) spectral indices are Γ=\Gamma=3.8±\pm0.3, 4.3±\pm0.6 and 4.5±\pm0.2 in 2009, 2011 and 2013, respectively. No significant spectral change across the observation epochs is detected. We find no evidence for variability at gamma-ray opacities of greater than τ=2\tau=2, where it is postulated that any variability would be small and occur on longer than year timescales if hadronic cosmic-ray interactions with extragalactic photon fields provide a secondary VHE photon flux. The data cannot rule out such variability due to low statistics.Comment: ApJL accepted March 17, 201

    Terrorists, rioters and crocodiles: The political symbolism of an Olympic monster

    No full text
    This is a post-peer-review, pre-copyedit version of an article published in British Politics. The definitive publisher-authenticated version - British Politics, 2014, 9(2), pp. 161-181 - is available online at: http://www.palgrave-journals.com/bp/journal/v9/n2/full/bp201317a.htmlIn August 2005, just a month after the announcement that London had succeeded in its bid to host the 2012 Olympic Games, the UK national press witnessed a brief rash of stories alleging the presence of a crocodile or similar water monster lurking beneath the surface of the River Lea – the river that runs from the town of Luton in Bedfordshire down to join the Thames adjacent to the Olympic site. This story re-emerged in November 2011 when a campaigner against the environmental impact of the Olympics on the river area claimed to have seen further evidence of crocodilian activity. This paper will explore the reasons for the proliferation of this story, in terms both of its function as a metonymic news-hook (it opened up directly related concerns as to the impact, organization and security of the Games) and of its metaphorical significance (its incarnation of a superstructure’s fears of an emerging threat of a monstrous underclass – one which might at once comprise terrorists, rioters and anti-establishment campaigners). It will conclude by suggesting that this monstrous myth might hold within it the possibility of the convergence of populist news media and popular democracy

    A transcriptomic snapshot of early molecular communication between Pasteuria penetrans and Meloidogyne incognita

    Get PDF
    © The Author(s). 2018Background: Southern root-knot nematode Meloidogyne incognita (Kofoid and White, 1919), Chitwood, 1949 is a key pest of agricultural crops. Pasteuria penetrans is a hyperparasitic bacterium capable of suppressing the nematode reproduction, and represents a typical coevolved pathogen-hyperparasite system. Attachment of Pasteuria endospores to the cuticle of second-stage nematode juveniles is the first and pivotal step in the bacterial infection. RNA-Seq was used to understand the early transcriptional response of the root-knot nematode at 8 h post Pasteuria endospore attachment. Results: A total of 52,485 transcripts were assembled from the high quality (HQ) reads, out of which 582 transcripts were found differentially expressed in the Pasteuria endospore encumbered J2 s, of which 229 were up-regulated and 353 were down-regulated. Pasteuria infection caused a suppression of the protein synthesis machinery of the nematode. Several of the differentially expressed transcripts were putatively involved in nematode innate immunity, signaling, stress responses, endospore attachment process and post-attachment behavioral modification of the juveniles. The expression profiles of fifteen selected transcripts were validated to be true by the qRT PCR. RNAi based silencing of transcripts coding for fructose bisphosphate aldolase and glucosyl transferase caused a reduction in endospore attachment as compared to the controls, whereas, silencing of aspartic protease and ubiquitin coding transcripts resulted in higher incidence of endospore attachment on the nematode cuticle. Conclusions: Here we provide evidence of an early transcriptional response by the nematode upon infection by Pasteuria prior to root invasion. We found that adhesion of Pasteuria endospores to the cuticle induced a down-regulated protein response in the nematode. In addition, we show that fructose bisphosphate aldolase, glucosyl transferase, aspartic protease and ubiquitin coding transcripts are involved in modulating the endospore attachment on the nematode cuticle. Our results add new and significant information to the existing knowledge on early molecular interaction between M. incognita and P. penetrans.Peer reviewedFinal Published versio

    Comparison of sequencing-based methods to profile DNA methylation and identification of monoallelic epigenetic modifications.

    Get PDF
    Analysis of DNA methylation patterns relies increasingly on sequencing-based profiling methods. The four most frequently used sequencing-based technologies are the bisulfite-based methods MethylC-seq and reduced representation bisulfite sequencing (RRBS), and the enrichment-based techniques methylated DNA immunoprecipitation sequencing (MeDIP-seq) and methylated DNA binding domain sequencing (MBD-seq). We applied all four methods to biological replicates of human embryonic stem cells to assess their genome-wide CpG coverage, resolution, cost, concordance and the influence of CpG density and genomic context. The methylation levels assessed by the two bisulfite methods were concordant (their difference did not exceed a given threshold) for 82% for CpGs and 99% of the non-CpG cytosines. Using binary methylation calls, the two enrichment methods were 99% concordant and regions assessed by all four methods were 97% concordant. We combined MeDIP-seq with methylation-sensitive restriction enzyme (MRE-seq) sequencing for comprehensive methylome coverage at lower cost. This, along with RNA-seq and ChIP-seq of the ES cells enabled us to detect regions with allele-specific epigenetic states, identifying most known imprinted regions and new loci with monoallelic epigenetic marks and monoallelic expression
    corecore