Testing the Hidden Local Symmetry Model

The aim of this thesis is to test the recently proposed effective Lagrangian for pi, rho and gamma physics, called the Hidden Local Symmetry (HLS) model, against experimental data on the process gammagamma→rhorho. To this end Chapter 1 is a general introduction, motivating the interest in studying the HLS model in particular and pointing out its relation to composite models of Higgs and W/Z bosons. It is noted that there is a crucial sector of this model that has, until now, remained untested. It is observed that this untested sector can be probed by comparing the predictions of the model with the well established data on gammagamma→rhorho; which in itself is an interesting process and in need of better theoretical understanding. Chapter 2 is an introduction to the HLS model and in section (i) the construction of the model Lagrangian is presented. The HLS model has an arbitrary parameter 'a', it is shown in section (ii) that so far the attempts to determine 'a' by some "underlying" symmetry principle fail when confronted with phenomenology. In section (iii) the pivotal role of the HLS model of vector mesons in the Skyrmion picture of baryon physics is explained. Section (iv) summarises the chapter and underlines the need to test the HLS model fully. Chapter 3 is a summary of the current experimental and theoretical status of gammagamma→V1V2 physics (V1,2=rho, o, k*, ϕ). It is emphasised that there is still room for a "conventional explanation" of the process gammagamma→rhorho. Thus the second strand of the thesis is testing the possibility of the HLS model explaining the data on gammagamma-rhorho. Chapter 4 is the first order, or tree-level, calculation of gammagamma→rhorho in the HLS model, it is found to be in disagreement with experimental data. Which leads us to consider in chapter 5 the motivation for a one loop calculation of gammagamma→rhorho; the approach taken in estimating the loop corrections, in the spirit of chiral perturbation theory, is outlined. In chapter 6 the loop diagram calculation for gammagamma→pp is presented, the results indicate that the perturbative expansion fails. It is thus necessary to check this result before proceeding any further with the loop calculation. The rho+rho- scattering amplitudes in the HLS model are shown to violate unitarity in chapter 7, this is an independent check on the loop diagram 'calculation in chapter 6. In chapter 8 it is concluded that the HLS model fails to describe gammagamma→rhorho perturbatively. The discussion of the results of this thesis includes an outline of several interesting possibilities for future work

A New Approach to Streaming Data from the Cloud

This is the final version.Available from American Meteorological Society via the DOI in this record.Environmental datasets are becoming so large that they are increasingly being hosted in the compute cloud, where they can be efficiently analyzed and disseminated. However, this necessitates new ways of efficiently delivering environmental information across the Internet to users. We visualised a big atmospheric dataset in a web page by repurposing techniques normally used to stream HD video. You can try the prototype at http://demo.3dvis.informaticslab.co.uk/ng-3d-vis/apps/desktop/ or watch a video demonstration at www.youtube.com/watch?v=pzvk1ZNMvFY

Kotzebue and Russia

Separaat väljaandest: The Germanic Review, Oct. 1930, vol. V, no. 4http://tartu.ester.ee/record=b1924703~S1*es

Can the UNAIDS modes of transmission model be improved? A comparison of the original and revised model projections using data from a setting in west Africa.

OBJECTIVE: The UNAIDS modes of transmission model (MoT) is a user-friendly model, developed to predict the distribution of new HIV infections among different subgroups. The model has been used in 29 countries to guide interventions. However, there is the risk that the simplifications inherent in the MoT produce misleading findings. Using input data from Nigeria, we compare projections from the MoT with those from a revised model that incorporates additional heterogeneity. METHODS: We revised the MoT to explicitly incorporate brothel and street-based sex-work, transactional sex, and HIV-discordant couples. Both models were parameterized using behavioural and epidemiological data from Cross River State, Nigeria. Model projections were compared, and the robustness of the revised model projections to different model assumptions, was investigated. RESULTS: The original MoT predicts 21% of new infections occur in most-at-risk-populations (MARPs), compared with 45% (40-75%, 95% Crl) once additional heterogeneity and updated parameterization is incorporated. Discordant couples, a subgroup previously not explicitly modelled, are predicted to contribute a third of new HIV infections. In addition, the new findings suggest that women engaging in transactional sex may be an important but previously less recognized risk group, with 16% of infections occurring in this subgroup. CONCLUSION: The MoT is an accessible model that can inform intervention priorities. However, the current model may be potentially misleading, with our comparisons in Nigeria suggesting that the model lacks resolution, making it challenging for the user to correctly interpret the nature of the epidemic. Our findings highlight the need for a formal review of the MoT

24 [1×12] Wavelength Selective Switches Integrated on a Single 4k LCoS Device

This article demonstrates the design, assembly, optimisation, and characterisation of 24 [1 × 12] wavelength selective switches (WSSs) based on a single set of optics and a 4k liquid crystal on silicon (LCoS) device. The average insertion loss was measured to be 8.4 dB with an average crosstalk level of 26.9 dB. To our knowledge, this module with 312 fibre ports is the highest-capacity WSS demonstrated so far. The module can be flexibly reconfigured into different switches and port counts for advanced reconfigurable optical add/drop multiplexer (ROADM) applications

Can mother-to-child transmission of HIV be eliminated without addressing the issue of stigma? Modeling the case for a setting in South Africa.

BACKGROUND: Stigma and discrimination ontinue to undermine the effectiveness of the HIV response. Despite a growing body of evidence of the negative relationship between stigma and HIV outcomes, there is a paucity of data available on the prevalence of stigma and its impact. We present a probabilistic cascade model to estimate the magnitude of impact stigma has on mother-to-child-transmission (MTCT). METHODS: The model was parameterized using 2010 data from Johannesburg, South Africa, from which loss-to-care at each stage of the antenatal cascade were available. Three scenarios were compared to assess the individual contributions of stigma, non-stigma related barriers, and drug ineffectiveness on the overall number of infant infections. Uncertainty analysis was used to estimate plausible ranges. The model follows the guidelines in place in 2010 when the data were extracted (WHO Option A), and compares this with model results had Option B+ been implemented at the time. RESULTS: The model estimated under Option A, 35% of infant infections being attributed to stigma. This compares to 51% of total infections had Option B+ been implemented in 2010. Under Option B+, the model estimated fewer infections than Option A, due to the availability of more effective drugs. Only 8% (Option A) and 9% (Option B+) of infant infections were attributed to drug ineffectiveness, with the trade-off in the proportion of infections being between stigma and non-stigma-related barriers. CONCLUSIONS: The model demonstrates that while the effect of stigma on retention of women at any given stage along the cascade can be relatively small, the cumulative effect can be large. Reducing stigma may be critical in reaching MTCT elimination targets, because as countries improve supply-side factors, the relative impact of stigma becomes greater. The cumulative nature of the PMTCT cascade results in stigma having a large effect, this feature may be harnessed for efficiency in investment by prioritizing interventions that can affect multiple stages of the cascade simultaneously