362 research outputs found
Information and communications technologies (ICT) in Higher Education teaching â a tale of gradualism rather than revolution
The widespread adoption of information and communications technologies (ICT) in higher education (HE) since the mid 1990s has failed to produce the radical changes in learning and teaching than many anticipated. Activity theory and Rogersâ model of the adoption of innovations provide analytic frameworks that help develop our understanding of the actual impact of ICT upon teaching practices. This paper draws on a series of large-scale surveys carried out over a 10 year period with distance education tutors at the UK Open University to explore the changing role of ICT in the work of teachers. It investigates how HE teachers in one large distance learning university have, over time, appropriated ICT applications as teaching tools, and the gradual rather than revolutionary changes that have resulted
Operation Moshtarak and the manufacture of credible, âheroicâ warfare
Richard Lance Keeble argues that Fleet Streetâs coverage of the Afghan conflict has served largely to promote the interests of the military/industrial/media complex â and marginalise the views of the public who have consistently appealed in polls for the troops to be brought back hom
Optically Mapping Multiple Bacterial Genomes Simultaneously in a Single Run
Optical mapping of bacterial chromosomes provides an unambiguous low-resolution sequence scaffold of the entire chromosome. In comparison to some techniques, such as pulse field gel electrophoresis, cost and throughput limit the application of this technique outside of genome finishing. We have demonstrated the production of multiple bacterial maps using a single set of consumables; this significantly reduces the time and expense of map production
On Convergence and Threshold Properties of Discrete Lotka-Volterra Population Protocols
In this work we focus on a natural class of population protocols whose
dynamics are modelled by the discrete version of Lotka-Volterra equations. In
such protocols, when an agent of type (species) interacts with an agent
of type (species) with as the initiator, then 's type becomes
with probability . In such an interaction, we think of as the
predator, as the prey, and the type of the prey is either converted to that
of the predator or stays as is. Such protocols capture the dynamics of some
opinion spreading models and generalize the well-known Rock-Paper-Scissors
discrete dynamics. We consider the pairwise interactions among agents that are
scheduled uniformly at random. We start by considering the convergence time and
show that any Lotka-Volterra-type protocol on an -agent population converges
to some absorbing state in time polynomial in , w.h.p., when any pair of
agents is allowed to interact. By contrast, when the interaction graph is a
star, even the Rock-Paper-Scissors protocol requires exponential time to
converge. We then study threshold effects exhibited by Lotka-Volterra-type
protocols with 3 and more species under interactions between any pair of
agents. We start by presenting a simple 4-type protocol in which the
probability difference of reaching the two possible absorbing states is
strongly amplified by the ratio of the initial populations of the two other
types, which are transient, but "control" convergence. We then prove that the
Rock-Paper-Scissors protocol reaches each of its three possible absorbing
states with almost equal probability, starting from any configuration
satisfying some sub-linear lower bound on the initial size of each species.
That is, Rock-Paper-Scissors is a realization of a "coin-flip consensus" in a
distributed system. Some of our techniques may be of independent value
Computer memories: the history of computer form
This paper looks at the computer as a truly global form. The similar beige boxes found in offices across the world are analysed from the perspective of design history rather than that of the history of science and technology. Through the exploration of an archive of computer manufacturer's catalogues and concurrent design texts, this paper examines the changes that have occurred in the production and consumption of the computer in the context of the workplace, from its inception as a room-sized mainframe operated through a console of flashing lights, to the personal computer as a 'universal' form, reproduced by many manufacturers. It shows how the computer in the past has been as diverse as any other product, and asks how and why it now appears as a standardised, sanitised object. In doing so our relationship with the office computer, past and present is explored, revealing a complex history of vicissitude.</p
Factors affecting internal standard selection for quantitative elemental bio-imaging of soft tissues by LA-ICP-MS
Element response variations under different laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) operating conditions were investigated to identify important factors for selecting an internal standard (IS) for quantitative elemental bio-imaging. Analytes covering a range of atomic masses and first ionisation potentials (FIP) were selected to investigate the signal response variation with changes in laser spot diameter, mass bias and cell sampling position. In all cases, an IS improved experimental precision regardless of a close match in element mass or FIP but optimal analyte/IS combinations depended on the difference in masses of the analyte and IS. Particular attention was paid to 13C as this isotope is typically used as an IS in elemental bio-imaging applications. Despite its non-ideal IS characteristics (often different mass and FIP to many analytes), possibility of abundance sensitivity effects and poor signal-to-background ratio, 13C was a suitable IS candidate exhibiting a linear response with respect to the mass ablated, apparent independence from the high abundance of the adjacent 14N mass peak and effective analyte normalisation after background subtraction as long as the 13C signal from the sample was at least 6% of the gross signal. © 2011 The Royal Society of Chemistry
Identifying an Experimental Two-State Hamiltonian to Arbitrary Accuracy
Precision control of a quantum system requires accurate determination of the
effective system Hamiltonian. We develop a method for estimating the
Hamiltonian parameters for some unknown two-state system and providing
uncertainty bounds on these parameters. This method requires only one
measurement basis and the ability to initialise the system in some arbitrary
state which is not an eigenstate of the Hamiltonian in question. The scaling of
the uncertainty is studied for large numbers of measurements and found to be
proportional to one on the square-root of the number of measurements.Comment: Minor corrections, Accepted for publication in Physical Review
Variation of theanine, phenolic, and methylxanthine compounds in 21 cultivars of Camellia sinensis harvested in different seasons
This is the first study to use chemometric methods to differentiate among 21 cultivars of Camellia sinensis from China and between leaves harvested at different times of the year using 30 compounds implicated in the taste and quality of tea. Unique patterns of catechin derivatives were observed among cultivars and across harvest seasons. C. sinensis var. pubilimba (You 510) differed from the cultivars of C. sinensis var. sinensis, with higher levels of theobromine, (+)-catechin, gallocatechin, gallocatechin gallate and theasinensin B, and lower levels of (â)-epicatechin, (â)-epigallocatechin (EGC) and (-)-epigallocatechin gallate (EGCG), respectively. Three cultivars of C. sinensis var. sinensis, Fuyun 7, Qiancha 7 and Zijuan contained significantly more caffeoylquinic acids than others cultivars. A Linear Discriminant Analysis model based on the abundance of 12 compounds was able to discriminate amongst all 21 tea cultivars. Harvest time impacted the abundance of EGC, theanine and afzelechin gallate
Construct-level predictive validity of educational attainment and intellectual aptitude tests in medical student selection: meta-regression of six UK longitudinal studies
Background: Measures used for medical student selection should predict future performance during training. A problem for any selection study is that predictor-outcome correlations are known only in those who have been selected, whereas selectors need to know how measures would predict in the entire pool of applicants. That problem of interpretation can be solved by calculating construct-level predictive validity, an estimate of true predictor-outcome correlation across the range of applicant abilities.
Methods: Construct-level predictive validities were calculated in six cohort studies of medical student selection and training (student entry, 1972 to 2009) for a range of predictors, including A-levels, General Certificates of Secondary Education (GCSEs)/O-levels, and aptitude tests (AH5 and UK Clinical Aptitude Test (UKCAT)). Outcomes included undergraduate basic medical science and finals assessments, as well as postgraduate measures of Membership of the Royal Colleges of Physicians of the United Kingdom (MRCP(UK)) performance and entry in the Specialist Register. Construct-level predictive validity was calculated with the method of Hunter, Schmidt and Le (2006), adapted to correct for right-censorship of examination results due to grade inflation.
Results: Meta-regression analyzed 57 separate predictor-outcome correlations (POCs) and construct-level predictive validities (CLPVs). Mean CLPVs are substantially higher (.450) than mean POCs (.171). Mean CLPVs for first-year examinations, were high for A-levels (.809; CI: .501 to .935), and lower for GCSEs/O-levels (.332; CI: .024 to .583) and UKCAT (meanâ=â.245; CI: .207 to .276). A-levels had higher CLPVs for all undergraduate and postgraduate assessments than did GCSEs/O-levels and intellectual aptitude tests. CLPVs of educational attainment measures decline somewhat during training, but continue to predict postgraduate performance. Intellectual aptitude tests have lower CLPVs than A-levels or GCSEs/O-levels.
Conclusions: Educational attainment has strong CLPVs for undergraduate and postgraduate performance, accounting for perhaps 65% of true variance in first year performance. Such CLPVs justify the use of educational attainment measure in selection, but also raise a key theoretical question concerning the remaining 35% of variance (and measurement error, range restriction and right-censorship have been taken into account). Just as in astrophysics, âdark matterâ and âdark energyâ are posited to balance various theoretical equations, so medical student selection must also have its âdark varianceâ, whose nature is not yet properly characterized, but explains a third of the variation in performance during training. Some variance probably relates to factors which are unpredictable at selection, such as illness or other life events, but some is probably also associated with factors such as personality, motivation or study skills
Effect of a polyphenol-rich dietary pattern on intestinal permeability and gut and blood microbiomics in older subjects: study protocol of the MaPLE randomised controlled trial.
BACKGROUND:
During aging, alterations of the intestinal microbial ecosystem can occur contributing to immunosenescence, inflamm-aging and impairment of intestinal barrier function (increased intestinal permeability; IP). In the context of a diet-microbiota-IP axis in older subjects, food bioactives such as polyphenols may play a beneficial modulatory role.
METHODS:
MaPLE is a project centered on a randomized, controlled cross-over dietary intervention trial [polyphenol-rich diet (PR-diet) versus control diet (C-diet)] targeted to older people ( 65 60 y) living in a well-controlled setting (i.e. nursing home). The 8-week interventions are separated by an 8-week wash-out period. Three small portions per day of selected polyphenol-rich foods are consumed during intervention in substitution of other comparable products within the C-diet. Biological samples are collected before and after each treatment period to evaluate markers related to IP, inflammation, vascular function, oxidative stress, gut and blood microbiomics, metabolomics. A sample size of 50 subjects was defined based on IP as primary outcome.
DISCUSSION:
Evidence that increasing the consumption of polyphenol-rich food products can positively affect intestinal microbial ecosystem resulting in reduced IP and decreased translocation of inflammogenic bacterial factors into the bloodstream will be provided. The integration of data from gut and blood microbiomics, metabolomics and other IP-related markers will improve the understanding of the beneficial effect of the intervention in the context of polyphenols-microbiota-IP interactions. Finally, findings obtained will provide a proof of concept of the reliability of the dietary intervention, also contributing to future implementations of dietary guidelines directed to IP management in the older and other at risk subjects.
TRIAL REGISTRATION:
The trial is registered at (ISRCTN10214981); April 28, 2017
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