397 research outputs found
Quantum teardrops
Algebras of functions on quantum weighted projective spaces are introduced,
and the structure of quantum weighted projective lines or quantum teardrops are
described in detail. In particular the presentation of the coordinate algebra
of the quantum teardrop in terms of generators and relations and classification
of irreducible *-representations are derived. The algebras are then analysed
from the point of view of Hopf-Galois theory or the theory of quantum principal
bundles. Fredholm modules and associated traces are constructed. C*-algebras of
continuous functions on quantum weighted projective lines are described and
their K-groups computed.Comment: 18 page
Determination of the cyanobacterial toxin cylindrospermopsin in algal food supplements
For the analysis of blueâgreen algal food supplements for cylindrospermopsin (CYN), a C18 solid-phase extraction column and a polygraphitized carbon solid-phase extraction column in series was an effective procedure for the clean-up of extracts. Determination of CYN was by liquid chromatography with ultraviolet light detection. At extract spiking levels of CYN equivalent to 25â500 ÎŒg gâ1, blueâgreen algal supplement recoveries were in the range 70â90%. CYN was not detected in ten samples of food supplements and one chocolate product, all containing blueâgreen algae. The limit of detection for the method was 16 ÎŒg gâ1, and the limit of quantification was 52 ÎŒg gâ1
Dissolved Phosphorus Retention in Buffer Strips: Influence of Slope and Soil Type
Phosphorus (P) contributes to eutrophication of surface waters and buffer strips may be implemented to reduce its transfer from agricultural sources to watercourses. This study was conducted to test the hypothesis that soil type and slope influence the retention of dissolved organic P and inorganic orthophosphate in agricultural runoff in 2-m-wide buffer strip soils. A solution, comprised of dissolved orthophosphate and the organic P compounds glucose-1-phosphate, RNA, and inositol hexakisphosphate (1.8 mg Lâ1 total P) and a chloride tracer, was applied as simulated overland flow to grassland soil blocks (2 m long Ă 0.5 m wide Ă 0.35 m deep), containing intact clay or loam soils, at slope angles of 2, 5, and 10°. Phosphorus forms were determined in the surface and subsurface flow from the soil blocks. Slope had no significant effect on the hydrological behavior of the soil blocks or on the retention of any form of P at the water application rate tested. The clay soil retained 60% of the unreactive P and 21% of the reactive P applied. The loam soil retained 74% of the unreactive P applied but was a net source of reactive P (the load increased by 61%). This indicates leaching of native soil P or hydrolysis of organic compounds and complicates our understanding of P retention in buffer strip soils. Our results suggest that a 2-m buffer strip may be more effective for reducing dissolved unreactive P transfers to surface waters than for reducing the eutrophication risk posed by dissolved reactive P
ESRC/SFC Scoping Study into Quantitative Methods Capacity Building in Scotland
Final report for the following ITT: "The ESRC and the Funding Councils recognise that there is a growing body of evidence that highlights the need to develop quantitative skills amongst the social science population. In particular, this needs to take place during the earliest stages of career development, to ensure that there is a sufficient supply of quantitatively trained social science researchers entering the academic, public and voluntary sectors. To meet this need the ESRC is working with the Funding Councils to develop an integrated strategy which aims to improve the supply of quantitatively trained social scientists. To inform the development of this strategy the ESRC and SFC wish to commission a scoping study to identify the particular quantitative capacity building needs in Scotland. Tenders are currently being sought from individuals or teams interested in undertaking the study."There has been widespread concern about a UK-wide deficit in quantitative skills
amongst social scientists since the 1960s, especially in relation to the rapid pace of
change within the industry and the lack of adequately trained computing scientists.
âą Despite experiencing a relatively industrious period in the late 1960s and 1970s,
Scotlandâs provision of quantitative methods within social science is now
extremely patchy and as bad, if not worse, than that in the rest of the UK.
âą Scotland has a similar demographic profile to the rest of the UK in terms of social
sciences; but Scottish Higher Educational Institutions (HEI) are under-represented
in other respects (e.g. representation at the Essex Summer School).
âą In Scotland, disciplines such as Economics, Accountancy, Business Studies and
Psychology, which already have a quantitative reputation, have better resources
for assessment, training and improvement of mathematical, statistical and general
quantitative skills of their graduate students than other disciplines.
âą Undergraduate courses are mainly focused around generic rather than specialised
quantitative methods teaching, although there is more specialist provision at
postgraduate level, but this again is centred around the âusualâ disciplines.
âą Most teaching and research involves fairly general methods and statistical
techniques, although there are a few people experienced in more âadvancedâ
methods. There is a widespread need for continuing professional development
training in Scotland across all sectors, mainly at the more advanced level. There are a few, small-scale centres of expertise in Scotland, but most quantitative
researchers are spread across a range of institutions and disciplines. There are no
large-scale networks or centres, and this is viewed as key to building capacity.
âą There are three general barriers to developing quantitative methods capacity in
Scotland. In order of importance, these are âantipathyâ (reluctance by students,
staff and HEI colleagues to engage with quantitative methods); âaccessibilityâ
(availability of/time for training); and âenablingâ (lack of funding, collaborative
opportunities and data access).
âą Scotland is a relatively âdata richâ country, with a proliferation in recent years of
Government funded surveys. However, self-reported usage of Scottish datasets is
low and there is a general failure to make the most of available data in Scotland.
âą Computing and library support services are not well tuned to the needs of
quantitative capacity building. Basic levels of support, such as finding resources
on the web and offering assistance to access these, are provided; however,
students get little extensive user support or instruction in use of datasets and staff
do not get support for statistical consultancy or teaching data analysis skills in
computer labs. Greater communication and collaboration between support and
research staff is needed.
âą There is support in Scotland for a long-term, strategic approach to building
capacity and there are good reasons for developing a specifically Scottish strategy.
âą A national strategy must include a variety of activities at a range of different
levels, such as: boosting numeracy in secondary schools; better engagement with
both undergraduate and graduate students; strengthening links between academia
and potential employers; more training through continuing professional
development; and mentoring for early career researchers. Boosting capacity will require cultural and structural changes within many
institutions and disciplinary areas. Universities and funding bodies must provide
strategic investment in order to build a strong infrastructure capable of supporting
a critical mass of quantitative trained researchers in Scotland. The recommendations from this study include creating a Scottish Centre for
Social Science Research Methods and establishing a Scottish Summer School
Commentary:Transcranial stimulation of the frontal lobes increases propensity of mind-wandering without changing meta-awareness
Commentary:Transcranial stimulation of the frontal lobes increases propensity of mind-wandering without changing meta-awareness
Disparate MgII Absorption Statistics towards Quasars and Gamma-Ray Bursts : A Possible Explanation
We examine the recent report by Prochter et al. (2006) that gamma-ray burst
(GRB) sight lines have a much higher incidence of strong MgII absorption than
quasar sight lines. We propose that the discrepancy is due to the different
beam sizes of GRBs and quasars, and that the intervening MgII systems are
clumpy with the dense part of each cloudlet of a similar size as the quasars,
i.e. < 10^16 cm, but bigger than GRBs. We also discuss observational
predictions of our proposed model. Most notably, in some cases the intervening
MgII absorbers in GRB spectra should be seen varying, and quasars with smaller
sizes should show an increased rate of strong MgII absorbers. In fact, our
prediction of variable MgII lines in the GRB spectra has been now confirmed by
Hao et al. (2007), who observed intervening FeII and MgII lines at z=1.48 to be
strongly variable in the multi-epoch spectra of z=4.05 GRB060206.Comment: 12 pages, 2 figures; substantially revised model calculation;
accepted for publication in Astrophysics & Space Science as a Lette
Post-Eocene climate change, niche conservatism, and the latitudinal diversity gradient of New World birds
Towards âlanguages for allâ in England: the state of the debate
Whether the study of languages should be a core element of a balanced and broadly based curriculum for all pupils in Englandâs 11â16 state-funded secondary schools is also part of a wider debate concerning how to harness Englandâs rich linguistic and cultural diversity and improve the quality and range of language skills of the country. While learning a second language throughout compulsory schooling is increasingly the norm across the world, fewer than 50% of 14â16 year olds in state-funded schools in England gained a modern language qualiïŹcation (General CertiïŹcation of Secondary Education or GCSE) in 2015. From 2015, recent government education policy has required the majority of pupils commencing secondary school to study a language to GCSE level, suggesting that schools who do not comply will be unable to gain the top inspection grade. This paper reviews the state of the debate examining divergent and contradictory perspectives within education policy and in the literature. It concludes by setting out six conditions for achieving this policy goal for enabling secondary schools to successfully implement a coherent and relevant languages curriculum for all young people, such that they can develop the linguistic and intercultural competencies needed to contribute to and thrive in increasingly diverse local and global communities
Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC
Measurements of inclusive jet suppression in heavy ion collisions at the LHC
provide direct sensitivity to the physics of jet quenching. In a sample of
lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated
luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with
a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the
transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the
anti-kt algorithm with values for the distance parameter that determines the
nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of
the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp.
Jet production is found to be suppressed by approximately a factor of two in
the 10% most central collisions relative to peripheral collisions. Rcp varies
smoothly with centrality as characterized by the number of participating
nucleons. The observed suppression is only weakly dependent on jet radius and
transverse momentum. These results provide the first direct measurement of
inclusive jet suppression in heavy ion collisions and complement previous
measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables,
submitted to Physics Letters B. All figures including auxiliary figures are
available at
http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02
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