612 research outputs found
Clinical study of the teeth in cleft palate
The first responsibility of the dental surgeon is for the
patients teeth, and observations made at the Cleft Palate
Clinic revealed many features relating to the teeth that
required further investigation. This study was undertaken as
an investigation into the abnormalities of number, form, and
structure of the teeth in a group of children with cleft
palate.
As a result of this study it was hoped that a more
complete picture would emerge of the abnormalities of the
teeth in children with cleft palate, including the relationship
of such abnormalities with the development defects and
environmental upsets found in these patients.
The study is not concerned with the skeletal and occlusal
deformities which may frequently be associated with cleft
palate
Chiral rings and GSO projection in Orbifolds
The GSO projection in the twisted sector of orbifold background is sometimes
subtle and incompatible descriptions are found in literatures. Here, from the
equivalence of partition functions in NSR and GS formalisms, we give a simple
rule of GSO projection for the chiral rings of string theory in \C^r/\Z_n,
. Necessary constructions of chiral rings are given by explicit mode
analysis.Comment: 24 page
Next-to-leading order diphoton+2-jet production at the LHC
We present results from a recent calculation of prompt photon-pair production
in association with two jets to next-to-leading order (NLO) at the LHC. The
virtual contribution is evaluated using the BlackHat library, a numerical
implementation of on-shell methods for one-loop amplitudes, in conjunction with
SHERPA. We study four sets of cuts: standard jet cuts, a set of Higgs-related
cuts suggested by ATLAS, and corresponding sets which isolate the kinematic
region where the process becomes the largest background to Higgs production via
vector-boson fusion.Comment: 10 pages, 4 figures, Presented at 11th International Symposium on
Radiative Corrections (RADCOR 2013), 22-27 September 2013, Lumley Castle
Hotel, Durham, U
Towards a Stringy Resolution of the Cosmological Singularity
We study cosmological solutions to the low-energy effective action of
heterotic string theory including possible leading order corrections
and a potential for the dilaton. We consider the possibility that including
such stringy corrections can resolve the initial cosmological singularity.
Since the exact form of these corrections is not known the higher-derivative
terms are constructed so that they vanish when the metric is de Sitter
spacetime. The constructed terms are compatible with known restrictions from
scattering amplitude and string worldsheet beta-function calculations. Analytic
and numerical techniques are used to construct a singularity-free cosmological
solution. At late times and low-curvatures the metric is asymptotically
Minkowski and the dilaton is frozen. In the high-curvature regime the universe
enters a de Sitter phase.Comment: 6 pages, 2 Figures; minor revisions; references added; REVTeX 4;
version to appear in Phys. Rev.
Subtraction terms for one-loop amplitudes with one unresolved parton
Fully differential next-to-next-to-leading order calculations require a
method to cancel infrared singularities. In a previous publication, I discussed
the general setup for the subtraction method at NNLO. In this paper I give all
subtraction terms for electron-positron annihilation associated with one-loop
amplitudes with one unresolved parton. These subtraction terms are integrated
within dimensional regularization over the unresolved one-particle phase space.
The results can be used with all variants of dimensional regularization
(conventional dimensional regularization, the 't Hooft-Veltman scheme and the
four-dimensional scheme).Comment: 27 page
Next-to-Leading Order W + 5-Jet Production at the LHC
We present next-to-leading order QCD predictions for the total cross section
and for a comprehensive set of transverse-momentum distributions in W + 5-jet
production at the Large Hadron Collider. We neglect the small contributions
from subleading-color virtual terms, top quarks and some terms containing four
quark pairs. We also present ratios of total cross sections, and use them to
obtain an extrapolation formula to an even larger number of jets. We include
the decay of the boson into leptons. This is the first such computation
with six final-state vector bosons or jets. We use BlackHat together with
SHERPA to carry out the computation.Comment: RevTex, 27 pages, 7 figures, v2 minor corrections and corrected
reference
Structures and Heats of Formation of Simple Alkaline Earth Metal Compounds II: Fluorides, Chlorides, Oxides, and Hydroxides for Ba, Sr, and Ra
Geometry parameters, vibrational frequencies, heats of formation, bond dissociation energies, cohesive energies, and selected fluoride affinities (difluorides) are predicted for the late alkaline earth (Sr, Ba and Ra) oxides, fluorides, chlorides, and hydroxides at the coupled cluster theory [CCSD(T)] level. Additional corrections (scalar relativistic and pseudopotential corrections, vibrational zero-point energies, and atomic spin-orbit effects) were included to accurately calculate the total atomization energies and heats of formation following the Feller-Peterson-Dixon methodology. The calculated values are compared to the experimental data where available. In some cases, especially for Ra compounds, there are no experimental results or the experimental energetics and geometries are not reliable or have very large error bars. All of the Sr, Ba and Ra difluorides, dichlorides and dihydroxides are bent structures with the OMO bond angles decreasing going down the group. The cohesive energy of bulk Be dihalides are predicted to be quite low while those of Ra are relatively large. The fluoride affinities show that the difluorides are moderately strong Lewis acids and that such trifluorides may form under the appropriate experimental conditions
THE AMUNDSEN SEA LOW Variability, Change, and Impact on Antarctic Climate
The Amundsen Sea low (ASL) is a climatological low pressure center that exerts considerable influence on the climate of West Antarctica. Its potential to explain important recent changes in Antarctic climate, for example, in temperature and sea ice extent, means that it has become the focus of an increasing number of studies. Here, the authors summarize the current understanding of the ASL, using reanalysis datasets to analyze recent variability and trends, as well as ice-core chemistry and climate model projections, to examine past and future changes in the ASL, respectively. The ASL has deepened in recent decades, affecting the climate through its influence on the regional meridional wind field, which controls the advection of moisture and heat into the continent. Deepening of the ASL in spring is consistent with observed West Antarctic warming and greater sea ice extent in the Ross Sea. Climate model simulations for recent decades indicate that this deepening is mediated by tropical variability while climate model projections through the twenty-first century suggest that the ASL will deepen in some seasons in response to greenhouse gas concentration increases
3D ground model development for an active landslide in Lias mudrocks using geophysical, remote sensing and geotechnical methods
A ground model of an active and complex landslide system in instability prone Lias mudrocks of North Yorkshire, UK is developed through an integrated approach, utilising geophysical, geotechnical and remote sensing investigative methods. Surface geomorphology is mapped and interpreted using immersive 3D visualisation software to interpret airborne light detection and ranging data and aerial photographs. Subsurface structure is determined by core logging and 3D electrical resistivity tomography (ERT), which is deployed at two scales of resolution to provide a means of volumetrically characterising the subsurface expression of both site scale (tens of metres) geological structure, and finer (metre to sub-metre) scale earth-flow related structures. Petrophysical analysis of the borehole core samples is used to develop relationships between the electrical and physical formation properties, to aid calibration and interpretation of 3D ERT images. Results of the landslide investigation reveal that an integrated approach centred on volumetric geophysical imaging successfully achieves a detailed understanding of structure and lithology of a complex landslide system, which cannot be achieved through the use of remotely sensed data or discrete intrusive sampling alone
- âŠ