1,467 research outputs found
Diagnosing Musculoskeletal Tumours
In 1993 we became aware of a worrying increase in apparent errors in the histopathological diagnosis of musculoskeletal
tumours in our Unit. As a result all cases seen over the past 8 years were reviewed by an independent panel. Of the 1996
cases reviewed there was an error in 87. In 54 cases (2.7%) this had led to some significant change in the active management
of the patient. The main areas where errors arose were in those very cases where clinical and radiological features were not
helpful in confirming or refuting the diagnosis. The incidence of errors rose with the passage of time, possibly related to a
deterioration in the pathologist’s health. The error rate in diagnosing bone tumours in previously published series ranges
from 9 to 40%. To ensure as accurate a rate of diagnosis as possible multidisciplinary working and regular audit are essential
Impact of Unexpected Events, Shocking News and Rumours on Foreign Exchange Market Dynamics
We analyze the dynamical response of the world's financial community to
various types of unexpected events, including the 9/11 terrorist attacks as
they unfolded on a minute-by-minute basis. We find that there are various
'species' of news, characterized by how quickly the news get absorbed, how much
meaning and importance is assigned to it by the community, and what subsequent
actions are then taken. For example, the response to the unfolding events of
9/11 shows a gradual collective understanding of what was happening, rather
than an immediate realization. For news items which are not simple economic
statements, and hence whose implications are not immediately obvious, we
uncover periods of collective discovery during which collective opinions seem
to oscillate in a remarkably synchronized way. In the case of a rumour, our
findings also provide a concrete example of contagion in inter-connected
communities. Practical applications of this work include the possibility of
producing selective newsfeeds for specific communities, based on their likely
impact
Autonomous clustering using rough set theory
This paper proposes a clustering technique that minimises the need for subjective
human intervention and is based on elements of rough set theory. The proposed algorithm is
unified in its approach to clustering and makes use of both local and global data properties to
obtain clustering solutions. It handles single-type and mixed attribute data sets with ease and
results from three data sets of single and mixed attribute types are used to illustrate the
technique and establish its efficiency
Globalising assessment: an ethnography of literacy assessment, camels and fast food in the Mongolian Gobi
What happens when standardised literacy assessments travel globally? The paper presents an ethnographic account of adult literacy assessment events in rural Mongolia. It examines the dynamics of literacy assessment in terms of the movement and re-contextualisation of test items as they travel globally and are received locally by Mongolian respondents. The analysis of literacy assessment events is informed by Goodwin’s ‘participation framework’ on language as embodied and situated interactive phenomena and by Actor Network Theory. Actor Network Theory (ANT) is applied to examine literacy assessment events as processes of translation shaped by an ‘assemblage’ of human and non-human actors (including the assessment texts)
On morphological hierarchical representations for image processing and spatial data clustering
Hierarchical data representations in the context of classi cation and data
clustering were put forward during the fties. Recently, hierarchical image
representations have gained renewed interest for segmentation purposes. In this
paper, we briefly survey fundamental results on hierarchical clustering and
then detail recent paradigms developed for the hierarchical representation of
images in the framework of mathematical morphology: constrained connectivity
and ultrametric watersheds. Constrained connectivity can be viewed as a way to
constrain an initial hierarchy in such a way that a set of desired constraints
are satis ed. The framework of ultrametric watersheds provides a generic scheme
for computing any hierarchical connected clustering, in particular when such a
hierarchy is constrained. The suitability of this framework for solving
practical problems is illustrated with applications in remote sensing
Phylomemetics—Evolutionary Analysis beyond the Gene
Genes are propagated by error-prone copying, and the resulting variation provides the basis for phylogenetic reconstruction of evolutionary relationships. Horizontal gene transfer may be superimposed on a tree-like evolutionary pattern, with some relationships better depicted as networks. The copying of manuscripts by scribes is very similar to the replication of genes, and phylogenetic inference programs can be used directly for reconstructing the copying history of different versions of a manuscript text. Phylogenetic methods have also been used for some time to analyse the evolution of languages and the development of physical cultural artefacts. These studies can help to answer a range of anthropological questions. We propose the adoption of the term “phylomemetics” for phylogenetic analysis of reproducing non-genetic elements
Communicating climate knowledge proxies, processes, politics
This forum article is the product of interdisciplinary discussion at a conference on climate histories held inCambridge, United Kingdom, in early 2011, with the specific aim of building a network around the issue of communicating cultural knowledge of environmental change. The lead articles, by Kirsten Hastrup as an anthropologist and Simon Schaffer as a historian of science, highlight the role of agents and proxies. These are followed by five interdisciplinary commentaries, which engage with the lead articles through new ethnographic material, and a set of shorter commentaries by leading scholars of different disciplines. Finally, the lead authors respond to the discussion. In this debate, climate change does not emerge as a single preformed "problem." Rather, different climate knowledges appear as products of particular networks and agencies. Just as the identification of proxies creates agents (ice, mountains, informants) by inserting them into new networks, we hope that these cross-disciplinary exchanges will produce further conversations and new approaches to action. © 2012 by The Wenner-Gren Foundation for Anthropological Research
Phenetic distances in the Drosophila melanogaster-subgroup species and oviposition-site preference for food components
Oviposition-site preferences (O.S.P.) have been investigated in females of six sibling species of the Drosophila melanogaster subgroup. O.S.P. were determined for standard food components and yeast genotypes. Females of all species showed a strong preference for complete medium and avoidance of pure agar as an egg-deposition site.\ud
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Ecological trees of the species on the basis of rank correlations were constructed. In ‘no-choice’ situations they agree with phylogenetic trees obtained by different means but in ‘choice’ situations they do not agree too well.\ud
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All species showed a high egg production on live yeast compared with standard medium (with killed yeast) and D. erecta females demonstrated discrimination between yeast genotypes. Niche breadth calculated from survival on the sterol mutant yeasts correlated fairly well with phylogenetic trees
Visualizing the Anthropocene dialectically: Jessica Woodworth and Peter Brosens’ eco-crisis trilogy
The ambition of this article is to propose a way of visualizing the Anthropocene dialectically. As suggested by the Dutch atmospheric chemist Paul Crutzen and the professor of biology Eugene F. Stoermer, the term Anthropocene refers to a historical period in which humankind has turned into a geological force that transforms the natural environment in such a way that it is hard to distinguish between the human and the natural world. Crutzen and Stoermer explain that the Anthropocene has begun after the Holocene, the geological epoch that followed the last ice age and lasted until the industrial revolution. Drawing on a number of figures such as the “tenfold” increase in urbanisation, the extreme transformation of land surface by human action, the use of more than 50% of all accessible fresh water by humans, and the massive increase in greenhouse emissions, Crutzen and Stoermer conclude that the term Anthropocene describes aptly mankind's influence on ecological and geological cycles (Crutzen & Stoermer, 2000, p.17). The wager of this article is that we need to identify ways to visualize the Anthropocene dialectically and I proceed to do so using as a case study Jessica Woodworth's and Peter Brosen's trilogy on the conflict between humans and nature, which consists of Khadak (2006), Altiplano (2009), and The Fifth Season (La Cinquième Saison, 2012)
Clustering of gene expression data: performance and similarity analysis
BACKGROUND: DNA Microarray technology is an innovative methodology in experimental molecular biology, which has produced huge amounts of valuable data in the profile of gene expression. Many clustering algorithms have been proposed to analyze gene expression data, but little guidance is available to help choose among them. The evaluation of feasible and applicable clustering algorithms is becoming an important issue in today's bioinformatics research. RESULTS: In this paper we first experimentally study three major clustering algorithms: Hierarchical Clustering (HC), Self-Organizing Map (SOM), and Self Organizing Tree Algorithm (SOTA) using Yeast Saccharomyces cerevisiae gene expression data, and compare their performance. We then introduce Cluster Diff, a new data mining tool, to conduct the similarity analysis of clusters generated by different algorithms. The performance study shows that SOTA is more efficient than SOM while HC is the least efficient. The results of similarity analysis show that when given a target cluster, the Cluster Diff can efficiently determine the closest match from a set of clusters. Therefore, it is an effective approach for evaluating different clustering algorithms. CONCLUSION: HC methods allow a visual, convenient representation of genes. However, they are neither robust nor efficient. The SOM is more robust against noise. A disadvantage of SOM is that the number of clusters has to be fixed beforehand. The SOTA combines the advantages of both hierarchical and SOM clustering. It allows a visual representation of the clusters and their structure and is not sensitive to noises. The SOTA is also more flexible than the other two clustering methods. By using our data mining tool, Cluster Diff, it is possible to analyze the similarity of clusters generated by different algorithms and thereby enable comparisons of different clustering methods
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