2,559 research outputs found

    A DSMC investigation of gas flows in micro-channels with bends

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    Pressure-driven, implicit boundary conditions are implemented in an open source direct simulation Monte Carlo (DSMC) solver, and benchmarked against simple micro-channel flow cases found in the literature. DSMC simulations are then carried out of gas flows for varying degrees of rarefaction along micro-channels with both one and two ninety-degree bends. The results are compared to those from the equivalent straight micro-channel geometry. Away from the immediate bend regions, the pressure and Mach number profiles do not differ greatly from those in straight channels, indicating that there are no significant losses introduced when a bend is added to a micro-channel geometry. It is found that the inclusion of a bend in a micro-channel can increase the amount of mass that a channel can carry, and that adding a second bend produces a greater mass flux enhancement. This increase happens within a small range of Knudsen number (0.02 Knin 0.08). Velocity slip and shear stress profiles at the channel walls are presented for the Knudsen showing the largest mass flux enhancement

    Evidence that the AGN dominates the radio emission in z ~ 1 radio-quiet quasars

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    This document is the Accepted Manuscript version of the following article: Sarah V. White, Matt J. Jarvis, Eleni Kalfoutnzou, Martin J. Hardcastle, Aprajita Verma, Mose M. Cao Orjales, and Jason Stevens, 'Evidence that the AGN dominates the radio emission in z ~ 1 radio quiet quasars', Monthly Notices of the Royal Astronomical Society, first published online 3 February 2017, DOI: https://doi.org/10.1093/mnras/stx284 Key results are presented in Table 4 and Figure 7, which illustrates where the RQQs lie in relation to the far-infrared--radio correlation © 2017 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society.In order to understand the role of radio-quiet quasars (RQQs) in galaxy evolution, we must determine the relative levels of accretion and star-formation activity within these objects. Previous work at low radio flux-densities has shown that accretion makes a significant contribution to the total radio emission, in contrast with other quasar studies that suggest star formation dominates. To investigate, we use 70 RQQs from the Spitzer-Herschel Active Galaxy Survey. These quasars are all at zz ~ 1, thereby minimising evolutionary effects, and have been selected to span a factor of ~100 in optical luminosity, so that the luminosity dependence of their properties can be studied. We have imaged the sample using the Karl G. Jansky Very Large Array (JVLA), whose high sensitivity results in 35 RQQs being detected above 2 σ\sigma. This radio dataset is combined with far-infrared luminosities derived from grey-body fitting to Herschel photometry. By exploiting the far-infrared--radio correlation observed for star-forming galaxies, and comparing two independent estimates of the star-formation rate, we show that star formation alone is not sufficient to explain the total radio emission. Considering RQQs above a 2-σ\sigma detection level in both the radio and the far-infrared, 92 per cent are accretion-dominated, and the accretion process accounts for 80 per cent of the radio luminosity when summed across the objects. The radio emission connected with accretion appears to be correlated with the optical luminosity of the RQQ, whilst a weaker luminosity-dependence is evident for the radio emission connected with star formation.Peer reviewedFinal Accepted Versio

    ハクゲイ ノ クウソウ ショウセツ テキ モチーフ オ クツガエス コト

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    この論文は「白鯨」の主人公であるイシュマエルとアハブの英雄的な性格に強調を置いて始まっている。メルビルが読者のために作り上げた物語の世界は板挟みの世界であり、時には空想小説の性格を見せ、また時には皮肉的な悲劇の性格を見せている。この論文では板挟みの世界が切り崩され、「白鯨」の物語としての背景にある真実が解明されている。物語の主人公を取り囲む登場人物は皮肉的性質を持った古典的航海物語の登場人物であり、詳細に分析されている。最後にこの論文では、儀式の悪霊化や、曖昧な比喩や、アハブの誇大妄想による強迫観念とそれに起因する不毛の犠牲を通した空想小説的モチーフを覆すことに視点が置かれている

    ハーマン・メルビル ト ケイゾク テキ タンキュウ タイピー オムー マーディ ニ オケル コテン テキ コウカイ モノガタリ ノ ブンセキ ノ ガイヨウ

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    メルビルは、ポリネシアを舞台にした自らの三作の小説『タイピー』、『オムー』、『マーディ』における全ての関連性を否定しているが、三作品の主人公が乗り出す古典的航海物語における、物語の展開の統一性が認識できると強く考えられる。『タイピー』に始まる楽園探求は『オムー』を通して継続され、『マーディ』において完結される。これら三作の物語は、人生と体験の意義を探求する一人の男の放浪を主題としている。彼は二つの目的を達成しようと板挟みに悩む人間であり、一度漂着した楽園の平安を拒絶する一方で、同時に現実の不安や自分の置かれている荒々しい状況からの解放を追求している

    Pleasure into pain: The consequences of long-term opioid use

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    Abstract One consequence of repeated drug administration is the development of adaptations in the nervous system, sometimes termed 'drug-opposite' responses. During administration, the effects of the drug are diminished by these adaptations (tolerance), while cessation of drug use results in the emergence of these drug-opposite responses as the withdrawal syndrome. Recent evidence on pain responses challenges this simple notion of withdrawal and suggests that aversive drug-opposite states may play a more important role in drug dependence than previously thought. While opioids such as heroin produce analgesia, people with a history of opioid self-administration are hypersensitive to certain kinds of pain during the time they are under the influence of the analgesic drug. This suggests that in pain systems, the drug-opposite response exceeds the pain inhibiting effect of the drug itself. This hyperalgesia is evident in people with a history of heroin use and is not modified by methadone or buprenorphine treatment but is reduced by long-term abstinence from opioids. This same pattern of the drug-opposite response exceeding the drug effect may also occur for mood. While opioids cause elevation of mood, commonly described as euphoria and reduction of emotional distress, methadone maintenance participants show significant negative mood disturbance relative to controls. Thus, for pain and mood, the chronic opioid user under the influence of the drug does not experience an opioid effect diminished by tolerance but a state opposite to the effect of the drug. Increases in drug concentration arising from administration serve only to reduce the degree of pain and mood disturbance. These aversive pain and mood states may contribute to the motivation for continued drug use and the dysfunction associated with drug dependence.

    The norovirus NS3 protein is a dynamic lipid- and microtubule-associated protein involved in viral RNA replication

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    Norovirus (NoV) infections are a significant health burden to society, yet the lack of reliable tissue culture systems has hampered the development of appropriate antiviral therapies. Here we show that the NoV NS3 protein, derived from murine NoV (MNV), is intimately associated with the MNV replication complex and the viral replication intermediate double-stranded RNA (dsRNA). We observed that when expressed individually, MNV NS3 and NS3 encoded by human Norwalk virus (NV) induced the formation of distinct vesicle-like structures that did not colocalize with any particular protein markers to cellular organelles but localized to cellular membranes, in particular those with a high cholesterol content. Both proteins also showed some degree of colocalization with the cytoskeleton marker β-tubulin. Although the distribution of MNV and NV NS3s were similar, NV NS3 displayed a higher level of colocalization with the Golgi apparatus and the endoplasmic reticulum (ER). However, we observed that although both proteins colocalized in membranes counterstained with filipin, an indicator of cholesterol content, MNV NS3 displayed a greater association with flotillin and stomatin, proteins known to associate with sphingolipid- and cholesterol-rich microdomains. Utilizing time-lapse epifluorescence microscopy, we observed that the membrane-derived vesicular structures induced by MNV NS3 were highly motile and dynamic in nature, and their movement was dependent on intact microtubules. These results begin to interrogate the functions of NoV proteins during virus replication and highlight the conserved properties of the NoV NS3 proteins among the seven Norovirus genogroups
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