388 research outputs found

    Energy Dependent Contrast in Atomic-Scale Spin-Polarized Scanning Tunneling Microscopy ofMn3N2(010): Experiment and First-Principles Theory

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    The technique of spin-polarized scanning tunneling microscopy is investigated for its use in determining fine details of surface magnetic structure down to the atomic scale. As a model sample, the row-wise anti-ferromagnetic Mn3N2(010) surface is studied. It is shown that the magnetic contrast in atomic-scale images is a strong function of the bias voltage around the Fermi level. Inversion of the magnetic contrast is also demonstrated. The experimental SP-STM images and height profiles are compared with simulated SP-STM images and height profiles based on spin-polarized density functional theory. The success of different tip models in reproducing the non-magnetic and magnetic STM data is explored.Comment: 15 pages, 7 figure

    Organisational Transformation as a Consequence of Software-as-a-Service Usage by Small and Medium Enterprises

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    Cloud computing, and particularly Software-as-a-Service, is now in widespread use, but how organisations are potentially transformed by Software-as-a-Service usage needs greater understanding. How do organisations, particularly Small and Medium Enterprises, change their processes and structures after a period of time of using Software-as-a-Service solutions? This study used a qualitative method of investigation. Sixteen semi-structured interviews have been conducted with participants from eleven different organisations. It was found that all the organisations experienced transformation to some extent. The types of organisational transformation observed included changes to organisational processes, changes to the structures within the organisations and also changes to the role played by IT departments. Relationships between these forms of transformation were also found. A greater understanding of these transformations can help organisations gain greater benefits from Software-as-a-Service solutions

    Exploring the Social Networks of Online Investors

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    Online trading has now become the prevalent form of stock market investing. With a large percentage of investors now online, understanding how they make use of social media to share and gather information is of major interest to service providers, regulators, researchers and to investors themselves. Previous studies have explored public online investor networks such as stock forums, but few studies have investigated investors’ private online social networks. This paper reports on a qualitative study that interviewed 26 online investors about the various forms of social networks they participate in. Some online investors continue to rely on their private, offline networks of family and friends for information and advice. Other investors have taken their social networks online, but these online networks are still private. While investors do participate in public stock forums, it was also found that private social networks exist within these public virtual communities. Forum members get to know other members outside of the forums and form personal relationships. Such private social networks are not visible to outsiders

    Synthesis of Pyridinium Amphiphiles Used for Transfection and Some Characteristics of Amphiphile/DNA Complex Formation

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    Pyridinium amphiphiles have found practical use for the delivery of DNA into cells. Starting from 4-methylpyridine, a general synthesis has been devised for the production of pyridinium amphiphiles which allows variation in both the hydrophobic part and in the headgroup area of the compounds. By means of differential scanning microcalorimetry, zeta potential, particle size measurements and cryo electron microscopy, some characteristics of the pyridinium amphiphile/ DNA complexes have been determined.

    Ventricular Pacing in Children

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75351/1/j.1540-8159.1982.tb06565.x.pd

    CIDP Diagnostic Criteria and Response to Treatment

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    AbstractIntroduction: Diagnostic criteria for CIDP have been proven useful for clinical trials. However, use of these criteria in clinics has been limited by time constraints and unknown usefulness in predicting outcomes. Methods: A retrospective chart review of CIDP patients at the University of Kansas seen between 2008 and 2014 was performed. We determined the diagnostic criteria fulfilled by each patient and assessed treatment responses. A positive response was defined by improvement sensory or motor examination as determined by a neuromuscular physician.Results: There were 38 total patients included in the study. The response rate to IVIG in patients who fulfilled EFNS/PNS criteria was 20/22 (90.1%). Among patients who fulfilled AAN criteria, 8/9 (88.9%) responded positively to IVIG. Slightly lower response rates were seen in patients fulfilling INCAT criteria and Saperstein criteria at 10/15 (66.7%) and 12/17 (70.6%), respectively.Discussion: EFNS/PNS and AAN criteria can similarly predict IVIG treatment response

    A Multivariate Treatment of Bias for Sequential Data Assimilation: Application to the Tropical Oceans

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    International audienceThis paper discusses the problems arising from the presence of system bias in ocean data assimilation taking examples from the ECMWF ocean reanalysis used for seasonal forecasting. The examples illustrate how in a biased system, the non-stationary nature of the observing system is a handicap for the reliable representation of climate variability. It is also shown how the bias can be aggravated by the assimilation process, as is the case for the temperature bias in the eastern equatorial Pacific, linked to a spurious vertical circulation generated by the data assimilation. A generalized algorithm for treatment of bias in sequential data assimilation has been implemented. The scheme allows the control variables of the bias to be different from those for the state vector. Experiments were conducted to evaluate the sensitivity of the results to the choice of bias variables. Results highlight the importance of the correct choice of variables for the bias: while correcting the bias in the pressure field reduces the bias in temperature and in the velocity field, the direct correction of the bias in the temperature field reduces the temperature bias, but significantly increases the error in the velocity field. Analysis of the error statistics reveals that the bias term is not constant in time, but exhibits large interannual fluctuations. The bias algorithm has been generalized further to include temporal variations of the bias term. A memory factor is included to allow for the slow variations of the bias, and a prescribed bias term is added to represent errors known a-priori. Several experiments have been conducted to illustrate the sensitivity of the results to the time evolution of the bias

    The distribution and characterization of HNK-1 antigens in the developing avian heart

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    The heart originates from splanchnic mesoderm and to a lesser extent from neural crest cells. The HNK-1 monoclonal antibody is a marker for early migrating neural crest cells, but reacts also with structures which are not derived from the neural crest. We investigated whether heart structures are HNK-1 positive before neural crest cells colonize these target tissues. To that end, we determined the HNK-1 antigen expression in the developing avian heart on immunohistochemical sections and on Western blots. The HNK-1 immunoreactivity in the developing chick heart is compared with data from literature cm the localization of neural crest cells in chick/quail chimeras. Structures with neural crest contribution, including parts of the early outflow tract and the related endocardial cushions, the primordia of the semilunar valve leaflets and the aorticopulmonary septum were HNK-1 positive. Furthermore, other structures were HNK-1 positive, such as the atrioventricular cushions, the wall of the sinus venosus at stage HH 15 through 21, parts of the endocardium at E3, parts of the myocardium at E6, and the extracellular matrix in the myocardial base of the semilunar valves at E14. HNK-1 expression was particularly observed in morphologically dynamic regions such as the developing valves, the outflow tract cushion, the developing conduction system and the autonomie nervous system of the heart. We observed that atrioventricular endocardial cushions are HNK-1 positive. We conclude that: a HNK-1 immunoreactivity does not always coincide with the presence of neural crest cells or their derivatives; (2) the outflow tract cushions and atrioventricular endocardial cushions are HNK-1 positive before neural crest cells are expected (stage HH 19) to enter the endocardial cushions of the outflow tract; (3) the observed spatio-temporal HNK-1 patterns observed in the developing heart correspond with various HNK-1 antigens. Apart from a constant pattern of HNK-1 antigens during development, stage-dependent HNK-1 antigens were also found

    The real foundation of fictional worlds

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    I argue that judgements of what is ‘true in a fiction’ presuppose the Reality Assumption: the assumption that everything that is (really) true is fictionally the case, unless excluded by the work. By contrast with the more familiar Reality Principle, the Reality Assumption is not a rule for inferring implied content from what is explicit. Instead it provides an array of real-world truths that can be used in such inferences. I claim that the Reality Assumption is essential to our ability to understand stories, drawing on a range of empirical evidence that demonstrates our reliance on it in narrative comprehension. However, the Reality Assumption has several unintuitive consequences, not least that what is fictionally the case includes countless facts that neither authors nor readers could (or should) ever consider. I argue that such consequences provide no reason to reject the Reality Assumption. I conclude that we should take fictions, like non-fictions, to be about the real world
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