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Search Results: 1 - 10 of 19724 matches for " Richard Atkinson "
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Extending basic principles of measurement models to the design and validation of Patient Reported Outcomes
Mark J Atkinson, Richard D Lennox
Health and Quality of Life Outcomes , 2006, DOI: 10.1186/1477-7525-4-65
Abstract: Over the past two decades, health outcomes researchers have tried to present convincing evidence to regulatory agencies and healthcare planners that Patient Reported Outcomes (PROs) provide a benefit beyond the assessment of clinical outcomes alone. This persistent belief in the added value of patients' ratings of illness and treatment has resulted in a continual refinement of PROs measures for use in clinical settings. Although conceptually and philosophically appealing, widespread acceptance of PROs has generally proved to be a challenge in regulatory and clinical environments, where a high value is placed on biomedical outcomes and where skepticism persists about the meaningfulness of such concepts such as quality of life, treatment satisfaction, and symptom distress. Contributing to such reluctance, some existing PRO measures have been openly criticized in the research literature as being inadequately conceptualized, lacking psychometric rigor, and based on inconsistently applied psychometric methods [1,2]. Such criticisms further undermine the credibility of PRO measures and tend to sideline their application in mainstream clinical research [3].Various stakeholder groups have attempted to address the situation by providing PRO development guidelines with which to evaluate and construct PRO measures. An influential example of such guidance was recently published by the Scientific Advisory Committee (SAC) of the Medical Outcomes Trust [4]. In this guidance the SAC states that PROs should be evaluated on the following seven dimensions; 1) the use of pre-specified conceptual and measurement models; 2) the strength of empirical support for the reliability and validity of the scale(s); 3) the responsiveness of PRO to clinical change; 4) the method(s) for interpreting scores; 5) the level of respondent and administrative burden; 6) the equivalence of alternative forms of administration; and 7) the rigor with which translations are adapted for use in specific cultural
Same formula, different figures: Change and persistence in class inequalities
Sociologia, Problemas e Práticas , 2010,
Abstract: many contemporary social theorists have argued that the social changes of the last few decades have shattered the hold of class over life histories, identities and politics and put in its place reflexive choice and individualism. this paper presents a summary of a recently completed research project in the uk designed to put these claims to the test. starting out from a “phenomeno-bourdieusian” model of class and deploying life history interviews it reveals not the decline of class in advanced capitalism, but its reinvention. new practices and pathways have emerged, but they represent only the shifting substance of class - the underlying structure of relational difference that defines class and produces different outcomes remains as patent as ever.
CytoJournal′s move to the new platform: More on financial model to the support open-access charter in cytopathology, publication quality indicators, and other issues
Shidham Vinod,Pitman Martha,DeMay Richard,Atkinson Barbara
CytoJournal , 2008,
An e-Infrastructure for Collaborative Research in Human Embryo Development
Adam Barker,Jano I. van Hemert,Richard A. Baldock,Malcolm P. Atkinson
Computer Science , 2009,
Abstract: Within the context of the EU Design Study Developmental Gene Expression Map, we identify a set of challenges when facilitating collaborative research on early human embryo development. These challenges bring forth requirements, for which we have identified solutions and technology. We summarise our solutions and demonstrate how they integrate to form an e-infrastructure to support collaborative research in this area of developmental biology.
Enhanced Usability of Managing Workflows in an Industrial Data Gateway
Gary A. McGilvary,Malcolm Atkinson,Sandra Gesing,Alvaro Aguilera,Richard Grunzke,Eva Sciacca
Computer Science , 2015,
Abstract: The Grid and Cloud User Support Environment (gUSE) enables users convenient and easy access to grid and cloud infrastructures by providing a general purpose, workflow-oriented graphical user interface to create and run workflows on various Distributed Computing Infrastructures (DCIs). Its arrangements for creating and modifying existing workflows are, however, non-intuitive and cumbersome due to the technologies and architecture employed by gUSE. In this paper, we outline the first integrated web-based workflow editor for gUSE with the aim of improving the user experience for those with industrial data workflows and the wider gUSE community. We report initial assessments of the editor's utility based on users' feedback. We argue that combining access to diverse scalable resources with improved workflow creation tools is important for all big data applications and research infrastructures.
Signs of selection in our genes
Nick Atkinson
Genome Biology , 2005, DOI: 10.1186/gb-spotlight-20050506-01
Abstract: Building on an earlier study, Cornell University's Rasmus Nielsen and colleagues compared over 13,000 annotated human genes and their chimp equivalents, using the ratio of synonymous to nonsynonymous mutations as evidence of positive selection. Their aim, Nielsen said, was to determine "which genes have been changing as humans and chimpanzees have evolved into their modern forms."The team subjected orthologous human–chimp gene pairs from published human data and polymerase chain reaction data obtained from a single male chimpanzee to likelihood analysis, which revealed any differences in mutation type ratio. They excluded genes with fewer than three nucleotide differences.Nielsen's team made several surprising discoveries, including increased positive selection on the X chromosome and a relative lack of positive selection on genes expressed in the brain. Many genes that showed signs of positive selection were involved in sensory perception or immune defenses, they report, and some of the strongest evidence for selection was seen in genes involved in apoptosis. The latter finding offers "a possible link between selfish mutations during spermatogenesis and cancer prevalence," Nielsen told The Scientist.Apoptosis kills a large proportion of cells during spermatogenesis. A mutation allowing a cell to avoid such a fate should spread in the population because it would confer a selective advantage. However, cancer cells are also eliminated by apoptosis, so any positive selection would be balanced against an increased risk of cancer. "Much of the same molecular machinery is used to destroy cancer cells," Nielsen explained.Justin Fay, a geneticist at Washington University's School of Medicine, said Nielsen's team has done "a great job of squeezing out any evidence for positive selection on protein coding sequences." However, he pointed to the limitations of their statistical modeling technique, which is only able to detect positive selection on a gene when it has multiple se
Little fire ant males are clones
Nick Atkinson
Genome Biology , 2005, DOI: 10.1186/gb-spotlight-20050630-01
Abstract: Denis Fournier, from Université Libre de Bruxelles in Belgium, and colleagues studied the DNA of queens, workers, males, and their sperm from 34 little ant nests in French Guiana. They expected to find a typical haplodiploidy genetic system, but instead discovered that queens possessed only maternally derived DNA, and males possessed only paternally derived DNA."If males are potentially in an evolutionary dead end, as is true in the little fire ant where workers are sterile and all queens are clonally produced, they do not have a means to transmit their genes to the next generation," said Fournier. Queens produce gynes (reproductively competent females) clonally, a strategy that denies males the opportunity to pass on their genes. Males are still required, however, in the production of workers, upon which a queen's own reproductive success depends even though males themselves gain nothing.The males' response has been to evolve their own means of clonal reproduction, Fournier and colleagues say. They propose that at some stage after fertilization, maternal genetic material is lost and a haploid male offspring, encoded solely by the sperm's DNA, develops. "We could think of the males as a separate, parasitic species that uses host eggs for its own reproduction," said Fournier."The reality with natural history is that if you look close enough, you find remarkable patterns," commented Greg Hurst, at University College London. This well-known ant species was previously thought to have a "classic bee-ant system of genetics," in which diploid females exist alongside maternally derived haploid males. But the "fascinating bit of natural history" uncovered by Fournier and colleagues tells a more complex story, in which males and females both reproduce asexually and have thus separated into distinct genetic lineages."In essence, the male-female interaction in this species has become like an obligate symbiosis—the females need the males for worker production and the males need
Lice tell mankind's story
Nick Atkinson
Genome Biology , 2004, DOI: 10.1186/gb-spotlight-20041006-01
Abstract: Modern humans - Homo sapiens - are generally thought to have passed through a tight population genetic "bottleneck" somewhere between 10,000 and 20,000 years ago. Parasites such as lice tend to be highly species specific, so by unravelling their evolutionary history it's possible to see past the bottleneck, according to the Florida Museum of Natural History's David Reed, lead author of the paper."The addition of parasite data to studies of primate and human evolutionary history is similar to having multiple camera angles recording an event," Reed told us. "We aim to create a better picture of human evolutionary history by studying lice, which might tell us something that human genetic studies alone either have not or cannot."Humans today play host to two separate genetic lineages of head and body lice. Although both occupy the same ecological niche, their most recent common ancestor lived over a million years ago, the study reports. One lineage has a global distribution, whereas the other appears to be limited to the New World.Reed and his colleagues present evidence that the New World lineage originally co-evolved with Homo erectus, but switched hosts to Homo sapiens around 25,000 years ago. The switch took place in Asia, the authors suggest, before the colonization of North America across the Bering Straits. The effective isolation of New World human populations until only a few hundred years ago allowed this second louse lineage to persist.Todd Disotell, of New York University's Department of Anthropology, was impressed by the study. "When I read this paper I was both intrigued and excited by Reed et al.'s findings," he said."I think that the conclusion that there was contact [in Asia] between remnant Homo erectus populations and modern Homo sapiens is correct, but the exact nature of that contact will be a continuing controversy," said Disotell. Physical contact certainly took place for the transmission of lice to be possible, but this doesn't necessarily equate
Platypus has 10 sex chromosomes
Nick Atkinson
Genome Biology , 2004, DOI: 10.1186/gb-spotlight-20041029-01
Abstract: "The platypus has long been known to have an unusual multiple set of sex chromosomes," said the University of Melbourne's professor Marilyn Renfree, who was not involved in the studies. However, the use of fluorescence in situ hybridization (FISH) confirmed how the ten elements segregate. "Remarkably, the five X chromosomes go into one cell, and the five Y into another," she continued. "This results in two kinds of sperm - half with XXXXX that determine female young and half with YYYYY that determine male young.""This sex chromosome system is unique in mammals," said the Australian National University's Frank Grützner, lead author of the Nature paper. "The only way to ensure that five X chromosomes end up in one sperm and five Y chromosomes in another is for all of the sex chromosomes to assemble in a certain pattern - X1Y1X2Y2X3Y3X4Y4X5Y5 - during meiosis. That's precisely what we found - a chain of alternating X and Y chromosomes."Willem Rens, lead author on paper in PNAS, said that his team used FISH to visualize each chromosome. "The paints are hybridized to metaphase cell preparations and reveal which chromosomes are present," said Rens, of Cambridge University's Resource Centre for Comparative Genomics. The technique allowed the researchers to discover how sex is determined at the chromosomal level, he told us, although at the level of the gene it remains a mystery.Peter Temple-Smith, at the University of Melbourne, met the new findings with enthusiasm. "The use of several extremely powerful, recently developed genetic techniques have unlocked some of the long-held secrets of sex determination in monotremes," he said. "The results suggest an otherwise unexpected evolutionary connection between bird and mammal sex chromosomes.""The complexity and intricacy of this system is mind-blowing," said Katherine Belov, of the Australian Museum's Evolutionary Biology Unit. "The fact that monotremes can manage such a large number of chromosomes is interesting in itself, b
Kinetics of the gas-phase reactions of OH radicals with alkanes and cycloalkanes
R. Atkinson
Atmospheric Chemistry and Physics (ACP) & Discussions (ACPD) , 2003,
Abstract: The available database concerning rate constants for gas-phase reactions of the hydroxyl (OH) radical with alkanes through early 2003 is presented over the entire temperature range for which measurements have been made (~180-2000 K). Measurements made using relative rate methods are re-evaluated using recent rate data for the reference compound (generally recommendations from this review). In general, whenever more than one study has been carried out over an overlapping temperature range, recommended rate constants or temperature-dependent rate expressions are presented. The recommended 298 K rate constants, temperature-dependent parameters, and temperature ranges over which these recommendations are applicable are listed in Table 1.
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