1,822 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 pathologistâs 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
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 Goodwinâs âparticipation frameworkâ 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 âassemblageâ of human and non-human actors (including the assessment texts)
Division of Giardia isolates from humans into two genetically distinct assemblages by electrophoretic analysis of enzyme encoded at 27 loci in comparison with Giardia muris
Giardia that infect humans are known to be heterogeneous but they are assigned currently to a single species, Giardia intestinalis (syn. G. lamblia). The genetic differences that exist within G. intestinalis have not yet been assessed quantitatively and neither have they been compared in magnitude with those that exist between G. intestinalis and species that are morphologically similar (G. duodenalis) or morphologically distinct (e.g. G. muris). In this study, 60 Australian isolates of G. intestinalis were analysed electrophoretically at 27 enzyme loci and compared with G. muris and a feline isolate of G. duodenalis. Isolates of G. intestinalis were distinct genetically from both G. muris (approximately 80% fixed allelic differences) and the feline G. duodenalis isolate (approximately 75% fixed allelic differences). The G. intestinalis isolates were extremely heterogeneous but they fell into 2 major genetic assemblages, separated by fixed allelic differences at approximately 60% of loci examined. The magnitude of the genetic differences between the G. intestinalis assemblages approached the level that distinguished the G. duodenalis isolate from the morphologically distinct G. muris. This raises important questions about the evolutionary relationships of the assemblages with Homo sapiens, the possibility of ancient or contemporary transmission from animal hosts to humans and the biogeographical origins of the two clusters.G. Mayrhofer, R. H. Andrews, P. L. Ey and N. B. Chilto
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
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
Bostonia: The Boston University Alumni Magazine. Volume 10
Founded in 1900, Bostonia magazine is Boston University's main alumni publication, which covers alumni and student life, as well as university activities, events, and programs
Analysis of Agglomerative Clustering
The diameter -clustering problem is the problem of partitioning a finite
subset of into subsets called clusters such that the maximum
diameter of the clusters is minimized. One early clustering algorithm that
computes a hierarchy of approximate solutions to this problem (for all values
of ) is the agglomerative clustering algorithm with the complete linkage
strategy. For decades, this algorithm has been widely used by practitioners.
However, it is not well studied theoretically. In this paper, we analyze the
agglomerative complete linkage clustering algorithm. Assuming that the
dimension is a constant, we show that for any the solution computed by
this algorithm is an -approximation to the diameter -clustering
problem. Our analysis does not only hold for the Euclidean distance but for any
metric that is based on a norm. Furthermore, we analyze the closely related
-center and discrete -center problem. For the corresponding agglomerative
algorithms, we deduce an approximation factor of as well.Comment: A preliminary version of this article appeared in Proceedings of the
28th International Symposium on Theoretical Aspects of Computer Science
(STACS '11), March 2011, pp. 308-319. This article also appeared in
Algorithmica. The final publication is available at
http://link.springer.com/article/10.1007/s00453-012-9717-
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. Š 2012 by The Wenner-Gren Foundation for Anthropological Research
PhylomemeticsâEvolutionary 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 âphylomemeticsâ for phylogenetic analysis of reproducing non-genetic elements
- âŚ