737 research outputs found

    The G1 phase Cdks regulate the centrosome cycle and mediate oncogene-dependent centrosome amplification

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    Because centrosome amplification generates aneuploidy and since centrosome amplification is ubiquitous in human tumors, a strong case is made for centrosome amplification being a major force in tumor biogenesis. Various evidence showing that oncogenes and altered tumor suppressors lead to centrosome amplification and aneuploidy suggests that oncogenes and altered tumor suppressors are a major source of genomic instability in tumors, and that they generate those abnormal processes to initiate and sustain tumorigenesis. We discuss how altered tumor suppressors and oncogenes utilize the cell cycle regulatory machinery to signal centrosome amplification and aneuploidy

    Why Some Interfaces Cannot be Sharp

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    A central goal of modern materials physics and nanoscience is control of materials and their interfaces to atomic dimensions. For interfaces between polar and non-polar layers, this goal is thwarted by a polar catastrophe that forces an interfacial reconstruction. In traditional semiconductors this reconstruction is achieved by an atomic disordering and stoichiometry change at the interface, but in multivalent oxides a new option is available: if the electrons can move, the atoms don`t have to. Using atomic-scale electron energy loss spectroscopy we find that there is a fundamental asymmetry between ionically and electronically compensated interfaces, both in interfacial sharpness and carrier density. This suggests a general strategy to design sharp interfaces, remove interfacial screening charges, control the band offset, and hence dramatically improving the performance of oxide devices.Comment: 12 pages of text, 6 figure

    The global oscillation network group site survey. II. Results

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    The Global Oscillation Network Group (GONG) Project will place a network of instruments around the world to observe solar oscillations as continuously as possible for three years. The Project has now chosen the six network sites based on analysis of survey data from fifteen sites around the world. The chosen sites are: Big Bear Solar Observatory, California; Mauna Loa Solar Observatory, Hawaii; Learmonth Solar Observatory, Australia; Udaipur Solar Observatory, India; Observatorio del Teide, Tenerife; and Cerro Tololo Interamerican Observatory, Chile. Total solar intensity at each site yields information on local cloud cover, extinction coefficient, and transparency fluctuations. In addition, the performance of 192 reasonable components analysis. An accompanying paper describes the analysis methods in detail; here we present the results of both the network and individual site analyses. The selected network has a duty cycle of 93.3%, in good agreement with numerical simulations. The power spectrum of the network observing window shows a first diurnal sidelobe height of 3 × 10⁻⁴ with respect to the central component, an improvement of a factor of 1300 over a single site. The background level of the network spectrum is lower by a factor of 50 compared to a single-site spectrum

    The Victorian Newsletter (Spring 1977)

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    The Victorian Newsletter is sponsored for the Victorian Group of the Modern Language Association by New York University and Queens College, City University of New York.The Victorian View of Russian Literature / Harold Orel -- Newman and the Victorian Cult of Style / David J. DeLaura -- Contrasting Pictorial Representations of Time: The Dural Narration of Bleak House / Devra Braun Rosenberg -- Swinburne's Craft of Pure Expression / Anthony H. Harrison -- Heart of Stone: An Emblem for Conversion / C. S. Vogel -- Thomas Hardy's Correspondence with Sir George Douglas / M. D. Wilkie -- Recent Publications: A Selected List / Arthur F. Minerof -- Victorian Group New

    Introducing the national COPD resources and outcomes project

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    <p>Abstract</p> <p>Background</p> <p>We report baseline data on the organisation of COPD care in UK NHS hospitals participating in the National COPD Resources and Outcomes Project (NCROP).</p> <p>Methods</p> <p>We undertook an initial survey of participating hospitals in 2007, looking at organisation and performance indicators in relation to general aspects of care, provision of non-invasive ventilation (NIV), pulmonary rehabilitation, early discharge schemes, and oxygen. We compare, where possible, against the national 2003 audit.</p> <p>Results</p> <p>100 hospitals participated. These were typically larger sized Units. Many aspects of COPD care had improved since 2003. Areas for further improvement include organisation of acute care, staff training, end-of-life care, organisation of oxygen services and continuation of pulmonary rehabilitation.</p> <p>Conclusion</p> <p>Key Points: positive change occurs over time and repeated audit seems to deliver some improvement in services. It is necessary to assess interventions such as the Peer Review used in the NCROP to achieve more comprehensive and rapid change.</p

    Motivations and experiences of museum visitors: The case of the Imperial War Museum, United Kingdom

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    This study explores motivations of visitors to the Imperial War Museum (North and South), United Kingdom, with a view to understanding why people visit museums associated with conflicts. Though museums are part of the education and leisure industry, the distinction between education and leisure is often blurred. There are a number of reasons why people visit museums. Motives of museum visitors can be grouped into intrinsic and extrinsic factors. This study analysed the extent to which museum visitors are motivated by extrinsic and intrinsic factors. Semi-structured interviews with visitors were conducted w at the Imperial Museum of War (North and South), United Kingdom. The findings do establish that extrinsic motivations are more dominant than the intrinsic ones for visiting the Imperial War Museum. The importance of extrinsic factors in motivating museum visitors would suggest that providing an opportunity for a good day out has more appeal to the visitors than the collections in the museum for the average visitors. The experiencing of museum in its totality is more important than the individual collections or the theme of the museum to the mainstream visitor. This work has made a contribution to understanding visitor motivations, which are multi-facetted, complex and not necessarily fully understood by the visitors themselves

    Exocomets from a Solar System Perspective

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    Exocomets are small bodies releasing gas and dust which orbit stars other than the Sun. Their existence was first inferred from the detection of variable absorption features in stellar spectra in the late 1980s using spectroscopy. More recently, they have been detected through photometric transits from space, and through far-IR/mm gas emission within debris disks. As (exo)comets are considered to contain the most pristine material accessible in stellar systems, they hold the potential to give us information about early stage formation and evolution conditions of extra Solar Systems. In the Solar System, comets carry the physical and chemical memory of the protoplanetary disk environment where they formed, providing relevant information on processes in the primordial solar nebula. The aim of this paper is to compare essential compositional properties between Solar System comets and exocomets. The paper aims to highlight commonalities and to discuss differences which may aid the communication between the involved research communities and perhaps also avoid misconceptions. Exocomets likely vary in their composition depending on their formation environment like Solar System comets do, and since exocomets are not resolved spatially, they pose a challenge when comparing them to high fidelity observations of Solar System comets. Observations of gas around main sequence stars, spectroscopic observations of "polluted" white dwarf atmospheres and spectroscopic observations of transiting exocomets suggest that exocomets may show compositional similarities with Solar System comets. The recent interstellar visitor 2I/Borisov showed gas, dust and nuclear properties similar to that of Solar System comets. This raises the tantalising prospect that observations of interstellar comets may help bridge the fields of exocomet and Solar System comets.Comment: 25 pages, 3 figures. To be published in PASP. This paper is the product of a workshop at the Lorentz Centre in Leiden, the Netherland

    Resolution, Relief, And Resignation:A Qualitative Study Of Responses To Misfit At Work

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    Research has portrayed person–environment (PE) fit as a pleasant condition resulting from people being attracted to and selected into compatible work environments; yet, our study reveals that creating and maintaining a sense of fit frequently involves an effortful, dynamic set of strategies. We used a two-phase, qualitative design to allow employees to report how they become aware of and experience misfit, and what they do in response. To address these questions, we conducted interviews with 81 individuals sampled from diverse industries and occupations. Through their descriptions, we identified three broad responses to the experience of misfit: resolution, relief, and resignation. Within these approaches, we identified distinct strategies for responding to misfit. We present a model of how participants used these strategies, often in combination, and develop propositions regarding their effectiveness at reducing strain associated with misfit. These results expand PE fit theory by providing new insight into how individuals experience and react to misfit—portraying them as active, motivated creators of their own fit experience at work
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