B_{s}^{0}\rightarrow D_{s}^{(*)+}D_{s}^{(*)-} decays in the LHCb detector, and a study of radiation damage in the Vertex Locator

The Large Hadron Collider (LHC) is currently the highest energy particle accelerator in the world, and is designed to collide protons at a centre-of-mass energy up to 14TeV. The LHCb experiment is one of four main experiments situated on the LHC ring, and is designed for making precision measurements of the decays of particles containing a b quark. In order to perform these measurements, it is necessary to precisely measure production and decay vertices in the collisions, and LHCb makes use of the Vertex Locator (VELO) to do this. The need for the VELO to be very close to the proton collision point requires it to be able to withstand high levels of radiation. This thesis presents studies of the damage suffered by the VELO during the full first run period of the LHC, with comparisons to the predicted levels of damage. It is observed that the VELO is performing well despite the radiation damage, and should continue to do so until the planned end of its operation. This thesis also presents the full analysis of the measurement of the branching fraction of the B_{s}^{0}\rightarrow~D_{s}^{(\ast)+}D_{s}^{(\ast)-} decay. This measurement is of interest theoretically as it may provide information about B_{s} oscillations, a phenomenon where B_{s} mesons spontaneously change to their anti-B_{s} anti-matter counterpart, and back. The analysis is performed on the full LHCb 2011 data set, consisting of approximately 1.1fb-1 of proton-proton collisions at centre-of-mass energy of 7TeV. The branching fraction is measured relative to the decay B^{0}\rightarrow D_{s}^{+}D^{-} in order to reduce the systematic uncertainty on the result, and is found to be: \BF(B_{s}^{0}\rightarrow~D_{s}^{(\ast)+}D_{s}^{(\ast)-}) = (3.07 \pm 0.10 (stat.) \pm 0.23 (sys.) \pm 0.34 (norm.))\%. This result is consistent with, and more precise than, all previous experimental determinations, and also the theoretical prediction

Global 21cm signal experiments: a designer's guide

[Abridged] The spatially averaged global spectrum of the redshifted 21cm line has generated much experimental interest, for it is potentially a direct probe of the Epoch of Reionization and the Dark Ages. Since the cosmological signal here has a purely spectral signature, most proposed experiments have little angular sensitivity. This is worrisome because with only spectra, the global 21cm signal can be difficult to distinguish from foregrounds such as Galactic synchrotron radiation, as both are spectrally smooth and the latter is orders of magnitude brighter. We establish a mathematical framework for global signal data analysis in a way that removes foregrounds optimally, complementing spectra with angular information. We explore various experimental design trade-offs, and find that 1) with spectral-only methods, it is impossible to mitigate errors that arise from uncertainties in foreground modeling; 2) foreground contamination can be significantly reduced for experiments with fine angular resolution; 3) most of the statistical significance in a positive detection during the Dark Ages comes from a characteristic high-redshift trough in the 21cm brightness temperature; and 4) Measurement errors decrease more rapidly with integration time for instruments with fine angular resolution. We show that if observations and algorithms are optimized based on these findings, an instrument with a 5 degree beam can achieve highly significant detections (greater than 5-sigma) of even extended (high Delta-z) reionization scenarios after integrating for 500 hrs. This is in contrast to instruments without angular resolution, which cannot detect gradual reionization. Abrupt ionization histories can be detected at the level of 10-100's of sigma. The expected errors are also low during the Dark Ages, with a 25-sigma detection of the expected cosmological signal after only 100 hrs of integration.Comment: 34 pages, 30 figures. Replaced (v2) to match accepted PRD version (minor pedagogical additions to text; methods, results, and conclusions unchanged). Fixed two typos (v3); text, results, conclusions etc. completely unchange

Professional Sports Teams: Going Beyond the Core

Purpose - The addition of products to the core of matches by Professional Sports Teams (PSTs) has received much coverage. However, there has been limited work as to how their stadiums are used to stage non-sporting events. This paper investigates how clubs in the English Football League (EFL) use their venues to diversify into other markets. Design/methodology - Secondary sources were used to categorise the teams who played in the EFL by: average division turnover, stadium capacity and stadium age. Semi-structured interviews were held with a member of the commercial teams of 21 clubs. Findings - Clubs use their stadiums to supply a range of products and working with partners is commonplace. These products are targeted at a range of stakeholders, such as supporters, the local community and regionally based organisations. In addition to their own efforts, increased geographical coverage for clubs usually develops in three ways: via internal marketing by local organisations who use the facilities, agents who market the stadium for the club, and the EFL who market the league/clubs holistically. Research limitations/implications - The use of a stadium allows PSTs to diversify by providing new products for new markets. In this instance it has led to the development of capabilities in areas such as conferencing, funerals and weddings. Originality - This is one of the first papers to examine the capabilities developed by PSTs that lie outside the staging of matches

The Primary Care National electronic Library for Health (NeLH-PC): a pilot of information-centred knowledge management for primary care - www.nelh-pc.nhs.uk

Introduction: The NeLH-PC (Primary Care National electronic Library for Health) was created as part of the NHS information strategy. It is designed to deliver knowledge to primary care. The rationale for developing this library as a knowledge management tool and where it sits within the science of knowledge management are described. Method: Focus groups were used to define the questions that arise in primary care that the NeLHPC should be seeking to answer. The Primary Care Library is subject to a cyclical programme of continuous improvement. Results: A site has been developed to meet users' needs and levels of expertise.NeLH-PC attracts from 500 000 to in excess of 800 000 hits per month. Conclusions: NeLH-PC provides an exemplar of how a limited range of knowledge management tools is utilised. More investment is needed if a broader range of tools is to be provided. Greater integration is required with educationalists and other information and knowledge services if the library's full potential is to be realised

The Effect of Ambient Air Pollution during Early Pregnancy on Fetal Ultrasonic Measurements during Mid-Pregnancy

BACKGROUND: Over the past decade there has been mounting evidence that ambient air pollution during pregnancy influences fetal growth. OBJECTIVES: This study was designed to examine possible associations between fetal ultrasonic measurements collected from 15,623 scans (13–26 weeks gestation) and ambient air pollution during early pregnancy. METHODS: We calculated mothers ’ average monthly exposures over the first 4 months of pregnancy for the following pollutants: particulate matter < 10 µm aerodynamic diameter (PM10), ozone, nitrogen dioxide, and sulfur dioxide. We examined associations with fetal femur length (FL), biparietal diameter (BPD), head circumference (HC), and abdominal circumference (AC). Final analyses included scans from only those women within 2 km of an air pollution monitoring site. We controlled for long-term trend, season, temperature, gestation, mother’s age, socioeconomic status, and fetal sex. RESULTS: A reduction in fetal AC was associated with O3 during days 31–60 [–1.42 mm; 95 % confidence interval (CI), –2.74 to –0.09], SO2 during days 61–90 (–1.67 mm; 95 % CI, –2.94 to –0.40), and PM10 during days 91–120 (–0.78 mm; 95 % CI, –1.49 to –0.08). Other results showed a reduction in BPD (–0.68 mm; 95 % CI, –1.09 to –0.27) associated with SO2 during days 0–30, a reduction in HC (–1.02 mm; 95 % CI, –1.78 to –0.26) associated with PM10 during days 91–120, and a reduction in FL associated with PM10 during days 0–30 (–0.28 mm; 95 % CI, –0.48 to –0.08) and 91–120 (–0.23; 95 % CI, –0.42 to –0.04). CONCLUSION: We found strong effects of ambient air pollution on ultrasound measures. Future research, including more individually detailed data, is needed to confirm our results. KEY WORDS: air pollution, fetal growth, pregnancy, temperature, ultrasound. Environ Health Perspect 116:362–369 (2008). doi:10.1289/ehp.10720 available vi

Cosmology with the Highly Redshifted 21cm Line

In addition to being a probe of Cosmic Dawn and Epoch of Reionization astrophysics, the 21cm line at $z>6$ is also a powerful way to constrain cosmology. Its power derives from several unique capabilities. First, the 21cm line is sensitive to energy injections into the intergalactic medium at high redshifts. It also increases the number of measurable modes compared to existing cosmological probes by orders of magnitude. Many of these modes are on smaller scales than are accessible via the CMB, and moreover have the advantage of being firmly in the linear regime (making them easy to model theoretically). Finally, the 21cm line provides access to redshifts prior to the formation of luminous objects. Together, these features of 21cm cosmology at $z>6$ provide multiple pathways toward precise cosmological constraints. These include the "marginalizing out" of astrophysical effects, the utilization of redshift space distortions, the breaking of CMB degeneracies, the identification of signatures of relative velocities between baryons and dark matter, and the discovery of unexpected signs of physics beyond the $\Lambda$CDM paradigm at high redshifts.Comment: Science white paper submitted to Decadal 2020 surve