103 research outputs found
The Roots of Radicalism: Natural Rights, Corporate Liberty, and Regional Factions in Colonial Connecticut, 1740-1766
This essay traces the roots of radicalism in Connecticut to the religious and economic upheavals of the early 1740s. Thereafter, radical ideas developed through debates over the independence of Yale College, the nature of the colony\u27s religious institutions, and the territorial expansion of a proprietary company. These debates had important similarities: All three addressed the validity of natural rights and the scope of corporate liberty, the right of groups to run themselves without outside interference. Moreover, the debates were politically bundled; the same men who held radical views on religion also held radical views on expansion. This faction led the ousters of Thomas Fitch, Governor of Connecticut, and Thomas Clap, President of Yale College. Building on its past radical arguments, this faction also provided the principal opposition to the Stamp Act. In this way, contrary to the standard history of the American Revolution, Connecticut radicalism began at home
Techniques of design optimisation for algorithms implemented in software
The overarching objective of this thesis was to develop tools for parallelising, optimising,
and implementing algorithms on parallel architectures, in particular General Purpose
Graphics Processors (GPGPUs). Two projects were chosen from different application areas
in which GPGPUs are used: a defence application involving image compression, and a
modelling application in bioinformatics (computational immunology). Each project had its
own specific objectives, as well as supporting the overall research goal.
The defence / image compression project was carried out in collaboration with the Jet
Propulsion Laboratories. The specific questions were: to what extent an algorithm designed
for bit-serial for the lossless compression of hyperspectral images on-board unmanned
vehicles (UAVs) in hardware could be parallelised, whether GPGPUs could be used to
implement that algorithm, and whether a software implementation with or without GPGPU
acceleration could match the throughput of a dedicated hardware (FPGA) implementation.
The dependencies within the algorithm were analysed, and the algorithm parallelised. The
algorithm was implemented in software for GPGPU, and optimised. During the optimisation
process, profiling revealed less than optimal device utilisation, but no further optimisations
resulted in an improvement in speed. The design had hit a local-maximum of performance.
Analysis of the arithmetic intensity and data-flow exposed flaws in the standard optimisation
metric of kernel occupancy used for GPU optimisation. Redesigning the implementation
with revised criteria (fused kernels, lower occupancy, and greater data locality) led to a new
implementation with 10x higher throughput. GPGPUs were shown to be viable for on-board
implementation of the CCSDS lossless hyperspectral image compression algorithm,
exceeding the performance of the hardware reference implementation, and providing
sufficient throughput for the next generation of image sensor as well.
The second project was carried out in collaboration with biologists at the University of
Arizona and involved modelling a complex biological system â VDJ recombination involved
in the formation of T-cell receptors (TCRs). Generation of immune receptors (T cell receptor
and antibodies) by VDJ recombination is an enormously complex process, which can
theoretically synthesize greater than 1018 variants. Originally thought to be a random
process, the underlying mechanisms clearly have a non-random nature that preferentially
creates a small subset of immune receptors in many individuals. Understanding this bias is a
longstanding problem in the field of immunology. Modelling the process of VDJ
recombination to determine the number of ways each immune receptor can be synthesized,
previously thought to be untenable, is a key first step in determining how this special
population is made. The computational tools developed in this thesis have allowed
immunologists for the first time to comprehensively test and invalidate a longstanding theory
(convergent recombination) for how this special population is created, while generating the
data needed to develop novel hypothesis
Meningitis and climate: from science to practice
Meningococcal meningitis is a climate sensitive infectious disease. The regional extent of the Meningitis Belt in Africa, where the majority of epidemics occur, was originally defined by Lapeysonnie in the 1960s. A combination of climatic and environmental conditions and biological and social factors have been associated to the spatial and temporal patterns of epidemics observed since the disease first emerged in West Africa over a century ago. However, there is still a lack of knowledge and data that would allow disentangling the relative effects of the diverse risk factors upon epidemics. The Meningitis Environmental Risk Information Technologies Initiative (MERIT), a collaborative research-to-practice consortium, seeks to inform national and regional prevention and control strategies across the African Meningitis Belt through the provision of new data and tools that better determine risk factors. In particular MERIT seeks to consolidate a body of knowledge that provides evidence of the contribution of climatic and environmental factors to seasonal and year-to-year variations in meningococcal meningitis incidence at both district and national scales. Here we review recent research and practice seeking to provide useful information for the epidemic response strategy of National Ministries of Health in the Meningitis Belt of Africa. In particular the research and derived tools described in this paper have focused at âgetting science into policy and practiceâ by engaging with practitioner communities under the umbrella of MERIT to ensure the relevance of their work to operational decision-making. We limit our focus to that of reactive vaccination for meningococcal meningitis. Important but external to our discussion is the development and implementation of the new conjugate vaccine, which specifically targets meningococcus A
Smart Moves: Effects of Relative Brain Size on Establishment Success of Invasive Amphibians and Reptiles
Brain size relative to body size varies considerably among animals, but the
ecological consequences of that variation remain poorly understood. Plausibly,
larger brains confer increased behavioural flexibility, and an ability to
respond to novel challenges. In keeping with that hypothesis, successful
invasive species of birds and mammals that flourish after translocation to a new
area tend to have larger brains than do unsuccessful invaders. We found the same
pattern in ectothermic terrestrial vertebrates. Brain size relative to body size
was larger in species of amphibians and reptiles reported to be successful
invaders, compared to species that failed to thrive after translocation to new
sites. This pattern was found in six of seven global biogeographic realms; the
exception (where relatively larger brains did not facilitate invasion success)
was Australasia. Establishment success was also higher in amphibian and reptile
families with larger relative brain sizes. Future work could usefully explore
whether invasion success is differentially associated with enlargement of
specific parts of the brain (as predicted by the functional role of the
forebrain in promoting behavioural flexibility), or with a general size increase
(suggesting that invasion success is facilitated by enhanced perceptual and
motor skills, as well as cognitive ability)
The Middle Pleistocene glacial evolution of northern East Anglia, UK: a dynamic tectonostratigraphic-parasequence approach
The Middle Pleistocene glacial history of northern East Anglia is a controversial topic with differing opinions surrounding chronology, provenance and the relative stratigraphic framework. Reconciling the stratigraphic framework of the region is an essential first step to developing onshoreâoffshore geological models and a robust event-driven chronological framework. Within this study a dynamic tectonostratigraphicâparasequence methodology is applied to deposits traditionally attributed to the Anglian Glaciation (Marine Isotope Stage 12). This approach offers an insight into ice-bed coupling during glaciation and how evolving boundary conditions influenced glacier dynamics. Six major tectonostratigraphicâparasequence assemblages (A1âA6) are recognized in northern East Anglia and correlate with successive advances into the region of North Sea or Pennine lobes of the British Ice Sheet. Individual tectonostratigraphicâparasequence assemblages are bound at their base by a sedimentary contact or, more commonly, a glacitectonic zone. The geometry and structural characteristics of these glacitectonic zones reflect temporal and spatial variations in ice-bed coupling (traction), a function of substrate rheology and, in turn, variations in lithology, porewater availability and thermo-mechanical properties. The role of permafrost may also be significant, promoting proglacial/ice-marginal thrust stacking in front of advancing ice and enhanced ice-bed decoupling during subsequent overriding and subglacial till accretio
Equilibrium Grade Inflation with Implications for Female Interest
We estimate an equilibrium model of grading policies where professors set grading policies and students register and study for classes, in part, based on these policies. Professors value enrollment, learning, and student study time, and set policies taking into account how other professors grade. Male and female students value course types, the benefits associated with higher grades, and effort costs differently. We calculate how much of the differences in grading policies across fields is driven by differences in demand for courses in those fields and how much is due to differences in professor preferences across fields. We also decompose differences in female/male course taking across fields driven by differences in i) cognitive skills, ii) valuation of grades, iii) cost of studying, and iv) field preferences. We then run counterfactual simulations to evalaute changes to grading policies. Restrictions on grading policies that equalize grade distributions across classes result in higher (lower) grades in science (non-science) fields but more (less) work being required. As women are willing to study more than men, this restriction on grading policies results in more women pursuing the sciences and more men pursuing the non-sciences
Motivation and Overview of Hydrological Ensemble Post-processing
In this introduction to this chapter on hydrologic post-processing, we discuss the different but complementary directives that the " artâ of post-processing must satisfy: the particular directive defined by specific applications and user needs; versus the general directive of making any ensemble member indistinguishable from the observations. Also discussed are the features of hydrologic post-pro- cessing that are similar and separate from meteorological post-processing, providing a tie-in to early chapters in this handbook. We also provide an overview of the different aspects the practitioner should keep in mind when developing and implementing algorithms to adequately " correct and calibrateâ ensemble fore- casts: when forecast uncertainties should be characterized separately versus maintaining a " lumpedâ approach; additional aspects of hydrological ensembles that need to be maintained to satisfy additional user requirements, such as temporal covariability in the ensemble time series, an overview of the different post-processing approaches being used in practice and in the literature, and concluding with a brief overview of more specific requirements and challenges implicit in the " artâ of post-processing
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