Subleading corrections to hadronic cross-sections at high energies

The Large Hadron Collider (LHC) has provided, and will continue to provide, data for collisions at the highest energies ever seen in a particle accelerator. A strong knowledge of the properties of amplitudes for Quantum Chromodynamics in the High Energy Limit is therefore important to interpret this data. We study this limit in the context of the High Energy Jets (HEJ) formalism. This formalism resums terms in the perturbative expansion of the cross-section that behave like αn/s log (s/-t)ⁿ¯¹, which are enhanced in this limit. Understanding this region is particularly important in certain key analyses at the LHC: for example, Higgs-boson- plus-dijet analyses where cuts are applied to pick out events with a large mjj and in many searches for new physics. In this thesis, we discuss two directions in which HEJ's accuracy has been improved. Firstly, we look at adding descriptions of partonic subprocesses which are formally sub-leading in the jet cross-section but Leading Logarithmic (LL) in the particular subprocess itself. This required the derivation of new effective vertices that describe the emission of a quark/anti-quark pair in a way that is consistent with the resummation procedure. The inclusion of such processes reduces HEJ's dependence on fixed-order calculations and marks an important step towards full Next-to-Leading Logarithmic (NLL) accuracy in the inclusive dijet cross-section. The second extension was to improve our description of events involving the emission of a Higgs boson along with jets. Specifically, we derive new effective vertices which keep the full dependence on the quark mass that appears in the loops that naturally arise in such amplitudes. The formalism is also simple enough to allow for any number of extra nal state jets in the process. Therefore, HEJ is unique in its ability to provide predictions for high-multiplicity Higgs-plus-jets processes with full nite quark mass e ects. Such a calculation is far beyond the reach of any xed order approach

A case of an obstructive intramural haematoma during percutaneous coronary intervention successfully treated with intima microfenestrations utilising a cutting balloon inflation technique

During percutaneous coronary interventions (PCI), good lesion preparation with adequate balloon predilatation is a fundamental step before stent deployment in order to achieve optimal stent expansion and favourable long-term outcomes post PCI. During PCI, inadvertent vessel tearing can occur, resulting in coronary dissections and formation of intramural haematomas. The latter might be associated with compression of the vessel lumen and significant compromise of the coronary blood flow leading to myocardial ischaemia and infarction. Herein, we present a case of intramural haematoma that occurred after PCI of the left anterior descending artery resulting in occlusion of the vessel and the subsequent use of a cutting balloon inflation technique to resolve the haematoma and restore the normal coronary blood flow

Association between inflammatory biomarkers and neointimal response following elective implantation of the ABSORB bioresorbable vascular scaffold

Introduction The ABSORB bioresorbable vascular scaffold (BVS) is associated with greater neointimal proliferation and thrombotic rate than the metal stent. The role of inflammatory biomarkers on neointimal proliferation has not been studied in the setting of BVS implantation. Patients and methods Thirty patients had arterial blood sampling before elective percutaneous coronary intervention with the ABSORB BVS and at 9-months follow-up. Plasma levels of interleukin-6, soluble CD40 ligand, monocyte chemotactic protein-1 and C-reactive protein were measured using enzyme-linked immunosorbent assay. Baseline and follow-up levels were compared for each biomarker. Optical frequency domain imaging was performed at follow-up and the neointimal burden was calculated as the ratio of neointimal area to scaffold area. The levels of inflammatory mediators were correlated with the neointimal burden. Results There was no significant increase in the levels of biomarkers from baseline to follow-up. Median C-reactive protein levels changed from 1.1 [interquartile range (IQR): 0.5–2.5] to 2.2 (IQR: 0.5–3.5) μg/ml, interleukin-6 from 1.0 (IQR: 0.6–1.4) to 1.0 (95% confidence interval: 0.6–1.4) pg/ml, monocyte chemotactic protein-1 from 120.4 (IQR: 86.0–153.4) to 102.0 (IQR: 70.3–148.1) pg/ml and soluble CD40 ligand from 108.3 (IQR: 74.1–173.7) to 112.0 (IQR: 71.0–225.9) pg/ml. The average neointimal burden in the cohort was 18±6%. Baseline, follow-up and change in plasma levels of inflammatory markers between these two time points did not correlate with the neointimal burden. Conclusion Elective percutaneous coronary intervention with the ABSORB BVS does not provoke a chronic inflammatory response. The degree of neointimal proliferation after elective implantation of the ABSORB BVS is independent of the pre-existing inflammatory environment

One-Sided Position-Dependent Smoothness-Increasing Accuracy-Conserving (SIAC) Filtering Over Uniform and Non-Uniform Meshes

In this paper, we introduce a new position-dependent Smoothness-Increasing Accuracy-Conserving (SIAC) filter that retains the benefits of position dependence while ameliorating some of its shortcomings. As in the previous position-dependent filter, our new filter can be applied near domain boundaries, near a discontinuity in the solution, or at the interface of different mesh sizes; and as before, in general, it numerically enhances the accuracy and increases the smoothness of approximations obtained using the discontinuous Galerkin (dG) method. However, the previously proposed position-dependent one-sided filter had two significant disadvantages: (1) increased computational cost (in terms of function evaluations), brought about by the use of $4k+1$ central B-splines near a boundary (leading to increased kernel support) and (2) increased numerical conditioning issues that necessitated the use of quadruple precision for polynomial degrees of $k\ge 3$ for the reported accuracy benefits to be realizable numerically. Our new filter addresses both of these issues --- maintaining the same support size and with similar function evaluation characteristicsas the symmetric filter in a way that has better numerical conditioning --- making it, unlike its predecessor, amenable for GPU computing. Our new filter was conceived by revisiting the original error analysis for superconvergence of SIAC filters and by examining the role of the B-splines and their weights in the SIAC filtering kernel. We demonstrate, in the uniform mesh case, that our new filter is globally superconvergent for $k=1$ and superconvergent in the interior (e.g., region excluding the boundary) for $k\ge2$. Furthermore, we present the first theoretical proof of superconvergence for postprocessing over smoothly varying meshes, and explain the accuracy-order conserving nature of this new filter when applied to certain non-uniform meshes cases. We provide numerical examples supporting our theoretical results and demonstrating that our new filter, in general, enhances the smoothness and accuracy of the solution. Numerical results are presented for solutions of both linear and nonlinear equation solved on both uniform and non-uniform one- and two-dimensional meshes

High throughput DNA sequencing to detect differences in the subgingival plaque microbiome in elderly subjects with and without dementia

BACKGROUND: To investigate the potential association between oral health and cognitive function, a pilot study was conducted to evaluate high throughput DNA sequencing of the V3 region of the 16S ribosomal RNA gene for determining the relative abundance of bacterial taxa in subgingival plaque from older adults with or without dementia. METHODS: Subgingival plaque samples were obtained from ten individuals at least 70 years old who participated in a study to assess oral health and cognitive function. DNA was isolated from the samples and a gene segment from the V3 portion of the 16S bacterial ribosomal RNA gene was amplified and sequenced using an Illumina HiSeq1000 DNA sequencer. Bacterial populations found in the subgingival plaque were identified and assessed with respect to the cognitive status and oral health of the participants who provided the samples. RESULTS: More than two million high quality DNA sequences were obtained from each sample. Individuals differed greatly in the mix of phylotypes, but different sites from different subgingival depths in the same subject were usually similar. No consistent differences were observed in this small sample between subjects separated by levels of oral health, sex, or age; however a consistently higher level of Fusobacteriaceae and a generally lower level of Prevotellaceae was seen in subjects without dementia, although the difference did not reach statistical significance, possibly because of the small sample size. CONCLUSIONS: The results from this pilot study provide suggestive evidence that alterations in the subgingival microbiome are associated with changes in cognitive function, and provide support for an expanded analysis of the role of the oral microbiome in dementia

A class of residual distribution schemes and their relation to relaxation systems

Residual distributions (RD) schemes are a class of of high-resolution finite volume methods for unstructured grids. A key feature of these schemes is that they make use of genuinely multidimensional (approximate) Riemann solvers as opposed to the piecemeal 1D Riemann solvers usually employed by finite volume methods. In 1D, LeVeque and Pelanti [J. Comp. Phys. 172, 572 (2001)] showed that many of the standard approximate Riemann solver methods (e.g., the Roe solver, HLL, Lax-Friedrichs) can be obtained from applying an exact Riemann solver to relaxation systems of the type introduced by Jin and Xin [Comm. Pure Appl. Math. 48, 235 (1995)]. In this work we extend LeVeque and Pelanti's results and obtain a multidimensional relaxation system from which multidimensional approximate Riemann solvers can be obtained. In particular, we show that with one choice of parameters the relaxation system yields the standard N-scheme. With another choice, the relaxation system yields a new Riemann solver, which can be viewed as a genuinely multidimensional extension of the local Lax-Friedrichs scheme. This new Riemann solver does not require the use Roe-Struijs-Deconinck averages, nor does it require the inversion of an m-by-m matrix in each computational grid cell, where $m$ is the number of conserved variables. Once this new scheme is established, we apply it on a few standard cases for the 2D compressible Euler equations of gas dynamics. We show that through the use of linear-preserving limiters, the new approach produces numerical solutions that are comparable in accuracy to the N-scheme, despite being computationally less expensive.Comment: 46 pages, 14 figure

Dearth and the English revolution : the harvest crisis of 1647-50

This article reconstructs the nature and scale of dearth in the late 1640s, emphasizing the coincidence of economic distress with constitutional crisis. It reconsiders the parish register evidence for subsistence crisis; examines the responses of central and local government; analyses the role of popular agency, especially though petitioning campaigns, in prompting reluctant magistrates to regulate the grain markets along lines stipulated by the late Elizabethan and early Stuart dearth orders, which had not been proclaimed since 1630; and accordingly suggests that the late 1640s represents a missing link in the historiography of responses to harvest failure