2,111 research outputs found
The afterlife of Laurence Sterne (1713-1768): Body snatching, dissection and the role of Cambridge anatomist Charles Collignon
This paper aims to highlight the practice of body snatching from graves in the 1700s for the purpose of providing corpses for anatomical dissection, and for stocking anatomy museums. To do this, we examine the exhumation and dissection of the famous eighteenth-century novelist Laurence Sterne and explore the involvement of Charles Collignon, Professor of Anatomy at the University of Cambridge. We also show that osteological and cut-mark analysis of a skull purported to be that of Sterne, currently housed in the Duckworth Collection at Cambridge, provides the key to solving the mystery surrounding why Sterne was resurrected
Cross Section Ratios between different CM energies at the LHC: opportunities for precision measurements and BSM sensitivity
The staged increase of the LHC beam energy provides a new class of
interesting observables, namely ratios and double ratios of cross sections of
various hard processes. The large degree of correlation of theoretical
systematics in the cross section calculations at different energies leads to
highly precise predictions for such ratios. We present in this letter few
examples of such ratios, and discuss their possible implications, both in terms
of opportunities for precision measurements and in terms of sensitivity to
Beyond the Standard Model dynamics.Comment: 19 pages, 9 figure
Diboson-Jets and the Search for Resonant Zh Production
New particles at the TeV-scale may have sizeable decay rates into boosted
Higgs bosons or other heavy scalars. Here, we investigate the possibility of
identifying such processes when the Higgs/scalar subsequently decays into a
pair of W bosons, constituting a highly distinctive "diboson-jet." These can
appear as a simple dilepton (plus MET) configuration, as a two-prong jet with
an embedded lepton, or as a four-prong jet. We study jet substructure methods
to discriminate these objects from their dominant backgrounds. We then
demonstrate the use of these techniques in the search for a heavy spin-one Z'
boson, such as may arise from strong dynamics or an extended gauge sector,
utilizing the decay chain Z' -> Zh -> Z(WW^(*)). We find that modes with
multiple boosted hadronic Zs and Ws tend to offer the best prospects for the
highest accessible masses. For 100/fb luminosity at the 14 TeV LHC, Z' decays
into a standard 125 GeV Higgs can be observed with 5-sigma significance for
masses of 1.5-2.5 TeV for a range of models. For a 200 GeV Higgs (requiring
nonstandard couplings, such as fermiophobic), the reach may improve to up to
2.5-3.0 TeV.Comment: 23 pages plus appendices, 9 figure
Cmr1/WDR76 defines a nuclear genotoxic stress body linking genome integrity and protein quality control
DNA replication stress is a source of genomic instability. Here we identify changed mutation rate 1 (Cmr1) as a factor involved in the response to DNA replication stress in Saccharomyces cerevisiae and show that Cmr1—together with Mrc1/Claspin, Pph3, the chaperonin containing TCP1 (CCT) and 25 other proteins—define a novel intranuclear quality control compartment (INQ) that sequesters misfolded, ubiquitylated and sumoylated proteins in response to genotoxic stress. The diversity of proteins that localize to INQ indicates that other biological processes such as cell cycle progression, chromatin and mitotic spindle organization may also be regulated through INQ. Similar to Cmr1, its human orthologue WDR76 responds to proteasome inhibition and DNA damage by relocalizing to nuclear foci and physically associating with CCT, suggesting an evolutionarily conserved biological function. We propose that Cmr1/WDR76 plays a role in the recovery from genotoxic stress through regulation of the turnover of sumoylated and phosphorylated proteins
Combination of electroweak and QCD corrections to single W production at the Fermilab Tevatron and the CERN LHC
Precision studies of the production of a high-transverse momentum lepton in
association with missing energy at hadron colliders require that electroweak
and QCD higher-order contributions are simultaneously taken into account in
theoretical predictions and data analysis. Here we present a detailed
phenomenological study of the impact of electroweak and strong contributions,
as well as of their combination, to all the observables relevant for the
various facets of the p\smartpap \to {\rm lepton} + X physics programme at
hadron colliders, including luminosity monitoring and Parton Distribution
Functions constraint, precision physics and search for new physics signals.
We provide a theoretical recipe to carefully combine electroweak and strong
corrections, that are mandatory in view of the challenging experimental
accuracy already reached at the Fermilab Tevatron and aimed at the CERN LHC,
and discuss the uncertainty inherent the combination. We conclude that the
theoretical accuracy of our calculation can be conservatively estimated to be
about 2% for standard event selections at the Tevatron and the LHC, and about
5% in the very high transverse mass/lepton transverse momentum tails. We
also provide arguments for a more aggressive error estimate (about 1% and 3%,
respectively) and conclude that in order to attain a one per cent accuracy: 1)
exact mixed corrections should be computed in
addition to the already available NNLO QCD contributions and two-loop
electroweak Sudakov logarithms; 2) QCD and electroweak corrections should be
coherently included into a single event generator.Comment: One reference added. Final version to appear in JHE
Predictions for Higgs production at the Tevatron and the associated uncertainties
We update the theoretical predictions for the production cross sections of
the Standard Model Higgs boson at the Fermilab Tevatron collider, focusing on
the two main search channels, the gluon-gluon fusion mechanism and
the Higgs-strahlung processes with , including all
relevant higher order QCD and electroweak corrections in perturbation theory.
We then estimate the various uncertainties affecting these predictions: the
scale uncertainties which are viewed as a measure of the unknown higher order
effects, the uncertainties from the parton distribution functions and the
related errors on the strong coupling constant, as well as the uncertainties
due to the use of an effective theory approach in the determination of the
radiative corrections in the process at next-to-next-to-leading
order. We find that while the cross sections are well under control in the
Higgs--strahlung processes, the theoretical uncertainties are rather large in
the case of the gluon-gluon fusion channel, possibly shifting the central
values of the next-to-next-to-leading order cross sections by more than
. These uncertainties are thus significantly larger than the
error assumed by the CDF and D0 experiments in their recent
analysis that has excluded the Higgs mass range 162-166 GeV at the 95%
confidence level. These exclusion limits should be, therefore, reconsidered in
the light of these large theoretical uncertainties.Comment: 40 pages, 12 figures. A few typos are corrected and some updated
numbers are provide
Gluon-gluon contributions to W+ W- production and Higgs interference effects
In this paper we complete our re-assessment of the production of W boson
pairs at the LHC, by calculating analytic results for the gg -> W+ W- -> (\nu l
l\nu) process including the effect of massive quarks circulating in the loop.
Together with the one-loop amplitudes containing the first two generations of
massless quarks propagating in the loop, these diagrams can give a significant
contribution with a large flux of gluons. One of the component parts of this
calculation is the production of a standard model Higgs boson, gg -> H and its
subsequent decay, H -> W+(-> \nu l) W-(-> l \nu). We will quantify the
importance of the interference between the Higgs boson production process and
the gluon-induced continuum production in the context of searches for the Higgs
boson at the Tevatron and the LHC. For instance, for mH < 140 GeV the effect of
the interference typically results in around a 10% reduction in the expected
number of Higgs signal events. The majority of this interference is due to
non-resonant contributions. Therefore cuts on the transverse mass such as those
currently used by the ATLAS collaboration reduce the destructive interference
to about a 1% effect. We advocate that a cut on the maximum transverse mass be
used in future Higgs searches in this channel
Lignin biomarkers as tracers of mercury sources in lakes water column
This study presents the role of specific terrigenous organic compounds as important vectors of mercury (Hg) transported from watersheds to lakes of the Canadian boreal forest. In order to differentiate the autochthonous from the allochthonous organic matter (OM), lignin derived biomarker signatures [Lambda, S/V, C/V, P/(V ? S), 3,5-Bd/V and (Ad/Al)v] were used. Since lignin is exclusively produced by terrigenous plants, this approach can give a non equivocal picture of the watershed inputs to the lakes. Moreover, it allows a characterization of the source of OM and its state of degradation. The water column of six lakes from the Canadian Shield was sampled monthly between June and September 2005. Lake total dissolved Hg concentrations and Lambda were positively correlated, meaning that Hg and ligneous inputs are linked (dissolved OM r2 = 0.62, p\0.0001; particulate OM r2 = 0.76, p\0.0001). Ratios of P/(V ? S) and 3,5-Bd/V from both dissolved OM and particulate OM of the water column suggest an inverse relationship between the progressive state of pedogenesis and maturation of the OM in soil before entering the lake, and the Hg concentrations in the water column. No relation was found between Hg levels in the lakes and the watershed flora composition—angiosperm versus gymnosperm or woody versus non-woody compounds. This study has significant implications for watershed management of ecosystems since limiting fresh terrestrial OM inputs should reduce Hg inputs to the aquatic systems. This is particularly the case for largescale land-use impacts, such as deforestation, agriculture and urbanization, associated to large quantities of soil OM being transferred to aquatic systems
Neutrino Mass and from a Mini-Seesaw
The recently proposed "mini-seesaw mechanism" combines naturally suppressed
Dirac and Majorana masses to achieve light Standard Model neutrinos via a
low-scale seesaw. A key feature of this approach is the presence of multiple
light (order GeV) sterile-neutrinos that mix with the Standard Model. In this
work we study the bounds on these light sterile-neutrinos from processes like
\mu ---> e + \gamma, invisible Z-decays, and neutrinoless double beta-decay. We
show that viable parameter space exists and that, interestingly, key
observables can lie just below current experimental sensitivities. In
particular, a motivated region of parameter space predicts a value of BR(\mu
---> e + \gamma) within the range to be probed by MEG.Comment: 1+26 pages, 7 figures. v2 JHEP version (typo's fixed, minor change to
presentation, results unchanged
Generic Algorithm to Predict the Speed of Translational Elongation: Implications for Protein Biogenesis
Synonymous codon usage and variations in the level of isoaccepting tRNAs exert a powerful selective force on translation fidelity. We have developed an algorithm to evaluate the relative rate of translation which allows large-scale comparisons of the non-uniform translation rate on the protein biogenesis. Using the complete genomes of Escherichia coli and Bacillus subtilis we show that stretches of codons pairing to minor tRNAs form putative sites to locally attenuate translation; thereby the tendency is to cluster in near proximity whereas long contiguous stretches of slow-translating triplets are avoided. The presence of slow-translating segments positively correlates with the protein length irrespective of the protein abundance. The slow-translating clusters are predominantly located down-stream of the domain boundaries presumably to fine-tune translational accuracy with the folding fidelity of multidomain proteins. Translation attenuation patterns at highly structurally and functionally conserved domains are preserved across the species suggesting a concerted selective pressure on the codon selection and species-specific tRNA abundance in these regions
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