1,263 research outputs found
Superconductor Insulator Transition in Long MoGe Nanowires
Properties of one-dimensional superconducting wires depend on physical
processes with different characteristic lengths. To identify the process
dominant in the critical regime we have studied trans- port properties of very
narrow (9-20 nm) MoGe wires fabricated by advanced electron-beam lithography in
wide range of lengths, 1-25 microns. We observed that the wires undergo a
superconductor -insulator transition that is controlled by cross sectional area
of a wire and possibly also by the thickness-to-width ratio. Mean-field
critical temperature decreases exponentially with the inverse of the wire cross
section. We observed that qualitatively similar superconductor{insulator
transition can be induced by external magnetic field. Some of our long
superconducting MoGe nanowires can be identified as localized superconductors,
namely in these wires one-electron localization length is much shorter than the
length of a wire
Controlled Tactile Exploration and Haptic Object Recognition
In this paper we propose a novel method for in-hand object recognition. The method is composed of a grasp stabilization controller and two exploratory behaviours to capture the shape and the softness of an object. Grasp stabilization plays an important role in recognizing objects. First, it prevents the object from slipping and facilitates the exploration of the object. Second, reaching a stable and repeatable position adds robustness to the learning algorithm and increases invariance with respect to the way in which the robot grasps the object. The stable poses are estimated using a Gaussian mixture model (GMM). We present experimental results showing that using our method the classifier can successfully distinguish 30 objects.We also compare our method with a benchmark experiment, in which the grasp stabilization is disabled. We show, with statistical significance, that our method outperforms the benchmark method
Land use change and the impact on greenhouse gas exchange in north Australian savanna soils
Savanna ecosystems are subjected to accelerating land use change as human
demand for food and forest products increases. Land use change has been
shown to both increase and decrease greenhouse gas fluxes from savannas and
considerable uncertainty exists about the non-CO<sub>2</sub> fluxes from the soil.
We measured methane (CH<sub>4</sub>), nitrous oxide (N<sub>2</sub>O) and carbon dioxide
(CO<sub>2</sub>) over a complete wet-dry seasonal cycle at three replicate sites
of each of three land uses: savanna, young pasture and old pasture
(converted from savanna 5–7 and 25–30 yr ago, respectively) in the
Douglas Daly region of Northern Australia. The effect of break of season
rains at the end of the dry season was investigated with two irrigation
experiments.
Land use change from savanna to pasture increased net greenhouse gas fluxes
from the soil. Pasture sites were a weaker sink for CH<sub>4</sub> than savanna
sites and, under wet conditions, old pastures turned from being sinks to a
significant source of CH<sub>4</sub>. Nitrous oxide emissions were generally very
low, in the range of 0 to 5 μg N<sub>2</sub>O-N m<sup>−2</sup> h<sup>−1</sup>, and under
dry conditions soil uptake of N<sub>2</sub>O was apparent. Break of season rains
produced a small, short lived pulse of N<sub>2</sub>O up to 20 μg N<sub>2</sub>O-N m<sup>−2</sup> h<sup>−1</sup>, most evident in pasture soil. Annual cumulative soil
CO<sub>2</sub> fluxes increased after clearing, with savanna (14.6 t CO<sub>2</sub>-C ha<sup>−1</sup> yr<sup>−1</sup>) having the lowest fluxes compared to old pasture
(18.5 t CO<sub>2</sub>-C ha<sup>−1</sup> yr<sup>−1</sup>) and young pasture (20.0 t CO<sub>2</sub>-C ha<sup>−1</sup> yr<sup>−1</sup>). Clearing savanna increased soil-based greenhouse gas
emissions from 53 to ∼ 70 t CO<sub>2</sub>-equivalents, a 30% increase
dominated by an increase in soil CO<sub>2</sub> emissions and shift from soil
CH<sub>4</sub> sink to source. Seasonal variation was clearly driven by soil water
content, supporting the emerging view that soil water content is a more
important driver of soil gas fluxes than soil temperature in tropical
ecosystems where temperature varies little among seasons
A log analysis study of 10 years of ebook consumption in academic library collections
Even though libraries have been offering eBooks for more than a decade, very little is known about eBook access and consumption in academic library collections. This paper addresses this gap with a log analysis study of eBook access at the library of the University of Waikato. This in-depth analysis covers a period spanning 10 years of eBook use at this university. We draw conclusions about the use of eBooks at this institution and compare the results with other published studies of eBook usage at tertiary institutes
Should patients with abnormal liver function tests in primary care be tested for chronic viral hepatitis: cost minimisation analysis based on a comprehensively tested cohort
Background
Liver function tests (LFTs) are ordered in large numbers in primary care, and the Birmingham and Lambeth Liver Evaluation Testing Strategies (BALLETS) study was set up to assess their usefulness in patients with no pre-existing or self-evident liver disease. All patients were tested for chronic viral hepatitis thereby providing an opportunity to compare various strategies for detection of this serious treatable disease.
Methods
This study uses data from the BALLETS cohort to compare various testing strategies for viral hepatitis in patients who had received an abnormal LFT result. The aim was to inform a strategy for identification of patients with chronic viral hepatitis. We used a cost-minimisation analysis to define a base case and then calculated the incremental cost per case detected to inform a strategy that could guide testing for chronic viral hepatitis.
Results
Of the 1,236 study patients with an abnormal LFT, 13 had chronic viral hepatitis (nine hepatitis B and four hepatitis C). The strategy advocated by the current guidelines (repeating the LFT with a view to testing for specific disease if it remained abnormal) was less efficient (more expensive per case detected) than a simple policy of testing all patients for viral hepatitis without repeating LFTs. A more selective strategy of viral testing all patients for viral hepatitis if they were born in countries where viral hepatitis was prevalent provided high efficiency with little loss of sensitivity. A notably high alanine aminotransferase (ALT) level (greater than twice the upper limit of normal) on the initial ALT test had high predictive value, but was insensitive, missing half the cases of viral infection.
Conclusions
Based on this analysis and on widely accepted clinical principles, a "fast and frugal" heuristic was produced to guide general practitioners with respect to diagnosing cases of viral hepatitis in asymptomatic patients with abnormal LFTs. It recommends testing all patients where a clear clinical indication of infection is present (e.g. evidence of intravenous drug use), followed by testing all patients who originated from countries where viral hepatitis is prevalent, and finally testing those who have a notably raised ALT level (more than twice the upper limit of normal). Patients not picked up by this efficient algorithm had a risk of chronic viral hepatitis that is lower than the general population
Avoiding obscure topics and generalising findings produces higher impact research
Much academic research is never cited and may be rarely read, indicating wasted effort from the authors, referees and publishers. One reason that an article could be ignored is that its topic is, or appears to be, too obscure to be of wide interest, even if excellent scholarship produced it. This paper reports a word frequency analysis of 874,411 English article titles from 18 different Scopus natural, formal, life and health sciences categories 2009-2015 to assess the likelihood that research on obscure (rarely researched) topics is less cited. In all categories examined, unusual words in article titles associate with below average citation impact research. Thus, researchers considering obscure topics may wish to reconsider, generalise their study, or to choose a title that reflects the wider lessons that can be drawn. Authors should also consider including multiple concepts and purposes within their titles in order to attract a wider audience
Looking Good: Mediatisation and International NGOs
Many international NGOs value those parts of their work that are suited to media representation: campaigning, advocacy, projects that produce the right sort of images. In this article I make three points about this change. First, those parts of the NGO most reliant on media – such as the campaign desk – may be becoming more powerful. This can change the internal dynamics of NGOs. Second, the increasing use of media means that NGOs, like other organisations, hold themselves accountable in new ways. Third, NGOs may appear to look more and more like media organisations. These changes have received relatively little attention in the literature on NGOs, though they reflect a broader set of debates about the role of media in society. Using a case analysis of an international NGO, I suggest that the concept of mediatisation might be a useful way to understand some of the changes observed in the NGO sector
Can Microsoft Academic be used for citation analysis of preprint archives? The case of the Social Science Research Network
This is an accepted manuscript of an article published by Springer in Scientometrics on 07/03/2018, available online: https://doi.org/10.1007/s11192-018-2704-z
The accepted version of the publication may differ from the final published version.Preprint archives play an important scholarly communication role within some fields. The impact of archives and individual preprints are difficult to analyse because online repositories are not indexed by the Web of Science or Scopus. In response, this article assesses whether the new Microsoft Academic can be used for citation analysis of preprint archives, focusing on the Social Science Research Network (SSRN). Although Microsoft Academic seems to index SSRN comprehensively, it groups a small fraction of SSRN papers into an easily retrievable set that has variations in character over time, making any field normalisation or citation comparisons untrustworthy. A brief parallel analysis of arXiv suggests that similar results would occur for other online repositories. Systematic analyses of preprint archives are nevertheless possible with Microsoft Academic when complete lists of archive publications are available from other sources because of its promising coverage and citation results
Corporate constructed and dissent enabling public spheres: differentiating dissensual from consensual corporate social responsibility
I here distinguish dissensual from consensual corporate social responsibility (CSR) on the grounds that the former is more concerned to organize (or portray) corporate-civil society disagreement than it is corporate-civil society agreement. In doing so, I first conceive of consensual CSR, and identify a positive and negative view thereof. Second, I conceive of dissensual CSR, and suggest that it can be actualized through the construction of dissent enabling, rather than consent-oriented, public spheres. Following this, I describe four actor-centred institutional theories-i.e. a sociological, ethical, transformative and economic perspective, respectively-and suggest that an economic perspective is generally well suited to explaining CSR activities at the organizational level. Accordingly, I then use the economic perspective to analyse a dissent enabling public sphere that Shell has constructed, and within which Greenpeace participated. In particular, I explain Shell's employment of dissensual CSR in terms of their core business interests; and identify some potential implications thereof for Shell, Greenpeace, and society more generally. In concluding, I highlight a number of ways in which the present paper can inform future research on business and society interactions
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