10,308 research outputs found
NNLL resummation for s-channel single top quark production
I present the next-to-next-to-leading-logarithm (NNLL) resummation of soft
and collinear gluon corrections to single top quark production in the s
channel. Attaining NNLL accuracy involves the calculation of the two-loop soft
anomalous dimension for the partonic subprocesses. Finite-order expansions of
the resummed cross section are calculated through next-to-next-to-leading order
(NNLO). Numerical results are presented for s-channel single top quark
production at the Tevatron and the LHC, including the dependence of the cross
sections on the top quark mass and the uncertainties in the theoretical
prediction. The higher-order corrections are significant for energies at both
colliders and they decrease the theoretical uncertainty.Comment: 17 pages, 12 figures; added figures and discussio
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Where's the harm? A social marketing approach to reframing 'problem' drinking cultures
Alcohol consumption is often linked to a broad range of social and health problems, yet alcohol also plays a fundamental role in social bonding between people. This paper considers the potential of social marketing to contribute to alcohol consumption reduction and reframe social norms that encourage 'problem' drinking. Based on qualitative research with a variety of Scottish drinkers, the paper emphasises how and why a better understanding of the culturally bound meanings of alcohol (e.g. social identity, self-concept) are of crucial importance to inform any social marketing approach to reframing excessive drinking
Effective affinities in microarray data
In the past couple of years several studies have shown that hybridization in
Affymetrix DNA microarrays can be rather well understood on the basis of simple
models of physical chemistry. In the majority of the cases a Langmuir isotherm
was used to fit experimental data. Although there is a general consensus about
this approach, some discrepancies between different studies are evident. For
instance, some authors have fitted the hybridization affinities from the
microarray fluorescent intensities, while others used affinities obtained from
melting experiments in solution. The former approach yields fitted affinities
that at first sight are only partially consistent with solution values. In this
paper we show that this discrepancy exists only superficially: a sufficiently
complete model provides effective affinities which are fully consistent with
those fitted to experimental data. This link provides new insight on the
relevant processes underlying the functioning of DNA microarrays.Comment: 8 pages, 6 figure
Scaffolding School Pupils’ Scientific Argumentation with Evidence-Based Dialogue Maps
This chapter reports pilot work investigating the potential of Evidence-based Dialogue Mapping to scaffold young teenagers’ scientific argumentation. Our research objective is to better understand pupils’ usage of dialogue maps created in Compendium to write scientific ex-planations. The participants were 20 pupils, 12-13 years old, in a summer science course for “gifted and talented” children in the UK. Through qualitative analysis of three case studies, we investigate the value of dialogue mapping as a mediating tool in the scientific reasoning process during a set of learning activities. These activities were published in an online learning envi-ronment to foster collaborative learning. Pupils mapped their discussions in pairs, shared maps via the online forum and in plenary discussions, and wrote essays based on their dialogue maps. This study draws on these multiple data sources: pupils’ maps in Compendium, writings in science and reflective comments about the uses of mapping for writing. Our analysis highlights the diversity of ways, both successful and unsuccessful, in which dialogue mapping was used by these young teenagers
Impact of earthquakes on agriculture during the Roman–Byzantine period from pollen records of the Dead Sea laminated sediment
The Dead Sea region holds the archives of a complex relationship between an ever-changing nature and
ancient civilisations. Regional pollen diagrams show a Roman–Byzantine period standing out in the recent
millennia by its wetter climate that allowed intensive arboriculture. During that period, the Dead Sea formed
laminites that display mostly a seasonal character. A multidisciplinary study focused on two earthquakes, 31
BC and AD 363, recorded as seismites in the Ze’elim gully A unit III which has been well dated by radiocarbon
in a previous study. The sampling of the sediment was done at an annual resolution starting from a few years
before and finishing a decade after each earthquake. A clear drop in agricultural indicators (especially Olea
and cereals) is shown. These pollen indicators mostly reflect human activities in the Judean Hills and coastal
oases. Agriculture was disturbed in large part of the rift valley where earthquake damage affected irrigation
and access to the fields. It took 4 to 5 yr to resume agriculture to previous conditions. Earthquakes must be
seen as contributors to factors damaging societies. If combined with other factors such as climatic aridification,
disease epidemics and political upheaval, they may lead to civilisation collapse
Intrinsic Tunneling in Cuprates and Manganites
The most anisotropic high temperature superconductors like Bi2Sr2CaCu2O8, as
well as the recently discovered layered manganite La1.4Sr1.6Mn2O7 are layered
metallic systems where the interlayer current transport occurs via sequential
tunneling of charge carriers. As a consequence, in Bi2Sr2CaCu2O8 adjacent CuO2
double layers form an intrinsic Josephson tunnel junction while in in
La1.4Sr1.6Mn2O7 tunneling of spin polarized charge carriers between adjacent
MnO2 layers leads to an intrinsic spin valve effect. We present and discuss
interlayer transport experiments for both systems. To perform the experiments
small sized mesa structures were patterned on top of single crystals of the
above materials defining stacks of a small number of intrinsic Josephson
junctions and intrinsic spin valves, respectively.Comment: 6 pages, 8 figure
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