1,786 research outputs found
How to Measure Group Selection in Real-world Populations
Multilevel selection and the evolution of cooperation are fundamental to the formation of higher-level organisation and the evolution of biocomplexity, but such notions are controversial and poorly understood in natural populations. The theoretic principles of group selection are well developed in idealised models where a population is neatly divided into multiple semi-isolated sub-populations. But since such models can be explained by individual selection given the localised frequency-dependent effects involved, some argue that the group selection concepts offered are, even in the idealised case, redundant and that in natural conditions where groups are not well-defined that a group selection framework is entirely inapplicable. This does not necessarily mean, however, that a natural population is not subject to some interesting localised frequency-dependent effects – but how could we formally quantify this under realistic conditions? Here we focus on the presence of a Simpson’s Paradox where, although the local proportion of cooperators decreases at all locations, the global proportion of cooperators increases. We illustrate this principle in a simple individual-based model of bacterial biofilm growth and discuss various complicating factors in moving from theory to practice of measuring group selection
The development and use of novel iridium complexes as catalysts for ortho-directed hydrogen isotope exchange reactions
The preparation and application of groups of new iridium complexes are described. In particular, iridium complexes possessing phosphine ligands and a bulky N-heterocyclic carbene have been shown to be robust and readily handled species and have been applied in a range of directed hydrogen-deuterium and -tritium exchange processes and, in particular, with drug-like substrates or within ADMET-related studies. Overall, these new iridium(I) complexes are shown to be highly active catalysts and display catalytic activity far in excess of the industry standard, Crabtree's catalyst, with excellent levels of labelling being achieved over short reaction times and at low metal complex loadings, whilst tolerating a wide range of functional moieties. Furthermore and again in contrast to systems employing Crabtree's catalyst, the low catalyst loadings and short reaction times made possible by these emerging iridium carbene comple have delivered tritiated products with very good levels of labelling and without any appreciable by-product waste production
The Impact of the Cold War on Textbook Treatments of American Constitutionalism
This study attempts to explore the impact, if any, of the surrounding social and political context on the high school civics curriculum, specifically its coverage of the Constitution and Bill of Rights. The research focuses specifically on the relationship between changes in Magruder\u27s American Government and the onset of Cold War tensions between the Soviet Union and the United States
Teaching for Student Success: Practical Ideas for the Classroom
Kyle Heys shares practical suggestions for teachers about how to engage and encourage students for success in the college classroom
What do we really know about infants who attend Accident and Emergency departments?
Aims: Accident and Emergency attendances continue to rise. Infants are disproportionately represented. This study examines the clinical reasons infants attend UK Accident and Emergency departments.
Methods: A retrospective review of 6,667 infants aged less than one year attending Accident and Emergency at two district general hospitals in London from 1st April 2009 to 30th March 2010. All infants had been assigned to a diagnostic category by the medical coding department according to National Health Service (NHS) data guidelines, based on the clinical diagnoses stated in the medical records. The Accident and Emergency case notes of a random subsample of 10% of infants in each of the top five recorded diagnostic categories (n = 535) were reviewed in detail and audited against the standard national NHS data set.
Results: The top 5 clinical diagnoses were ‘infectious diseases’, ‘gastrointestinal’, ‘respiratory’, ‘unclassifiable’ and ‘no abnormality detected’ (NAD). A third of infants were originally given a diagnosis of unclassifiable (21.5%) or NAD (11.5%). After detailed case-note review, we were able to reduce this to 9.7% (95% confidence interval (CI): 9.0, 10.4) and 8.8% (95% CI: 8.1, 9.5), respectively.
Conclusion: This study demonstrates the importance of providing a clear clinical diagnosis and coding system for Accident and Emergency attendances and understanding that system fully. This would allow for better informed health service evaluation, planning and research as each of these relies on the interpretation of routine health-care data. Furthermore, the relatively high proportion (10%) of infants attending with no discernible underlying medical abnormality suggests the health needs of a significant proportion of infants attending Accident and Emergency departments may be better addressed by alternative service provision and/or improved education and support to parents
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Extraction of anthropological data with ultrasound
This thesis was submitted for the degree of Doctor of Philosophy and was awarded by Brunel University.Human body scanners used to extract anthropological data have a significant drawback, the
subject is required to undress or wear tight fitting clothing. This thesis demonstrates an
ultrasonic based alternative to the current optical systems, that can potentially operate on a fully
clothed subject. To validate the concept several experiments were performed to determine the
acoustic properties of multiple garments. The results indicated that such an approach was
possible.
Beamforming is introduced as a method by which the ultrasonic scanning area can be increased,
the concept is thoroughly studied and a clear theoretical analysis is performed. Additionally,
Matlab has been used to demonstrate graphically, the results of such analysis, providing an
invaluable tool during the simulation, experimental and results stages of the thesis.
To evaluate beamfoming as a composite part of ultrasonic body imaging, a hardware solution
was necessary. During the concept phase, both FPGA and digital signal processors were
evaluated to determine their suitability for the role. An FPGA approach was finally chosen,
which allows highly parallel operation, essential to the high acquisition speeds required by some
beamforming methodologies. In addition, analogue circuitry was also designed to provide an
interface with the ultrasonic transducers, which, included variable gain amplifiers, charge
amplifiers and signal conditioning. Finally, a digital acquisition card was used to transfer data
between the FPGA and a desktop computer, on which, the sampled data was processed and
displayed in a coherent graphical manner.
The beamforming results clearly demonstrate that imaging multiple layers in air, with
ultrasound, is a viable technique for anthroplogical data collection. Furthermore, a wavelet
based method of improving the axial resolution is also proposed and demonstrated
Attitudes of year 10 boys and girls towards coeducational physical education in a metropolitan senior high school
The purpose of this study was to examine and compare student attitudes towards coeducational physical education at a selected metropolitan government secondary school. The study examined differences in attitudes between 66 Year 10 girls and 51 Year 10 boys and ascertained whether this difference was significant. A sub-purpose of the study was to determine physical education teachers\u27 perceptions of student attitudes toward coeducational physical education. This enabled a comparison to be made between the attitudes students expressed and the attitudes teachers perceived students to have. The investigation utilised a 16 item attitudinal questionnaire to establish whether students\u27 attitudes were positive or negative, and to determine whether the attitudes were correlated to the sex of the individual. Following the questionnaire an interview with students was conducted, which enabled determination of student attitudes and revealed possible reasons why these attitudes were held. Teachers\u27 perceptions of student attitudes toward coeducational physical education were evaluated through interviews conducted with staff members. As hypothesised the students were found to have positive attitudes towards coeducation a 1 physical education. The male students had more favourable attitudes than the female students, however, the difference was not statistically significant at the 0.05 level. The physical education teachers believed the students had positive attitudes towards coeducational physical education
Cognitive Science for the Classroom
Kyle Heys shares principles of cognitive science and how they can be used in the college classroom to enhance student learning
The UK's statutory defence for victims of modern slavery and its narrow understanding of victimhood
The Council of Europe Convention on Action Against Trafficking in Human Beings stipulates a ‘non-punishment principle’ which provides for the possibility of not imposing penalties on victims for crimes they were compelled to commit. This paper investigates the UK’s iteration of this principle: the statutory defence provided by section 45 of the Modern Slavery Act.Drawing on extant literature and relevant case law, this paperinvestigates current understandings of the statutory defence and theinsights these provide into broader understandings of criminalexploitation. It demonstrates that while practitioners understand theprocesses of the legislation surrounding the defence, they are lessknowledgeable about the nuances of modern slavery which thereforeimpacts the use and effectiveness of the defence. This paper challengesthe basis upon which criminal law is applied, and its analysis makes anoriginal contribution to recognising how misunderstandings of criminalexploitation can affect fairness in the criminal justice system
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