The South African Experience With Negotiated Versus Competitively Tendered Bus Contracts

Institute of Transport and Logistics Studies. Faculty of Economics and Business. The University of Sydne

The South African Experience With Negotiated Versus Competitively Tendered Bus Contracts

Institute of Transport and Logistics Studies. Faculty of Economics and Business. The University of Sydne

A Web Browsing Workload for Simulation

The simulation of packet switched networks depends on accurate web workload models as input for network models. We derived a workload model for traffic generated by an individual browsing the web. We derived the workload model by studying packet traces of web traffic generated by individuals browsing the web on a campus network. We attempted to model aggregate traffic generated by many web users browsing the web on a campus network, by decomposing the traffic into its constituent elements i.e. traffic generated by individual users. We furthermore identified elements within the traffic generated by individual users which contributed to the characteristics of the aggregate traffic stream. We identified parameters which were not directly inuenced by network specific characteristics such as latency and throughput, in order to ensure that our model was as general as possible. We found that web traffic was extremely complex. The dynamic behaviour of client and server side scripts introduced dependencies in the data. Our model was more detailed than any existing web workload model at the time the study was conducted, but did not take into account the behaviour of web client and server scripts. There is room for improvement in our model here. We tried to break down aggregate web traffic into parts which contain observations which were independent from each other. An analysis of autocorrelation between observations within parameter datasets showed that dependencies exist between observations in most of the parameter datasets. The dynamic behaviour of scripts might explain some of the dependencies in the parameter datasets. We implemented a measurement system which measured data on a campus network by extracting selected information from IP, TCP and HTTP message headers. The system extracted parameter datasets for our workload model from the captured data. The approach of capturing selected information from TCP/IP packets transmitted between web clients and servers as opposed to capturing all the data transmitted, avoided the problem of extremely large amounts of data accumulating over small periods of time. Capturing all the data transmitted between web clients and servers required large amounts of storage space and processing power which were not available to us. By using our measurement system, we were able to record data for a 30 day period, capturing web traffic generated by 6 692 hosts on a campus network. The measurement system could extract parameter datasets in real-time, or write selected data to secondary storage in order to extract parameter datasets off-line. The real-time version of the measurement system could not extract parameter datasets during peak traffic hours. We used the off-line version of the measurement system to obtain parameter datasets for the study. We believe that with certain optimisations the real-time system would be able to extract parameter datasets in real-time. We extracted parameter datasets from data recorded to secondary storage by the measurement system. We used the packet trace method to record data to secondary storage. Because of the nature of the packet trace method of measurement we did not have sufficient information in the recorded data to extract parameter datasets. We used a heuristic algorithm to extract parameter datasets from the incomplete data. The heuristic algorithm was novel as it used information from TCP, IP and HTTP package headers to recontruct a user's browsing behaviour. This had not been done before. The algorithm used a list of characteristics of web client requests which we compiled by studying packet traces of traffic generated by web users. The algorithm inferred user behaviour from the list of web client request characteristics. By using the algorithm we were able to extract parameter datasets from the incomplete measured data. We analysed the extracted parameter datasets by using visual techniques and goodness-of-fit measures. We tested several families of mathematical functions in order to find a function which fits the model parameter data well. The parameter datasets were very large. They typically contained millions of entries. The commercial statistical analysis packages we had at our disposal could not analyse datasets with millions of entries. We overcame the problem posed by the size of the datasets by implementing our analysis routines in the R statistical analysis environment. The R statistical analysis environment is a freely available open source software package. We implemented the Anderson Darling and (lambda)^2 goodness-of-fit statistics in the R statistical analysis environment for eight mathematical families of functions. We also implemented the Q-Q and P-P plots in order to visually analyse the data. We found that the Anderson Darling statistic could not be used to analyse large datasets. The Anderson Darling statistic did not have p-value tables for datasets with more than 200 observations. We used the (lambda)^2 statistic as an indicator of goodness-of-fit. The (lambda)^2 statistic indicated that there was evidence against a perfect fit between parameter datasets and any of the eight mathematical function families we tested for. At least one mathematical function did fit each dataset very well, albeit not perfectly well. The visual evidence provided by Q-Q and P-P plots corroborated this nding. We tabulated the data for each of the parameter datasets. Random values could be generated from the tabulated values

Does oral sodium bicarbonate therapy improve function and quality of life in older patients with chronic kidney disease and low-grade acidosis (the BiCARB trial)? Study protocol for a randomized controlled trial

Date of acceptance: 01/07/2015 © 2015 Witham et al. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Acknowledgements UK NIHR HTA grant 10/71/01. We acknowledge the financial support of NHS Research Scotland in conducting this trial.Peer reviewedPublisher PD

Processes Controlling Tropical Tropopause Temperature and Stratospheric Water Vapor in Climate Models

A warm bias in tropical tropopause temperature is found in the Met Office Unified Model (MetUM), in common with most models from phase 5 of CMIP (CMIP5). Key dynamical, microphysical, and radiative processes influencing the tropical tropopause temperature and lower-stratospheric water vapor concentrations in climate models are investigated using the MetUM. A series of sensitivity experiments are run to separate the effects of vertical advection, ice optical and microphysical properties, convection, cirrus clouds, and atmospheric composition on simulated tropopause temperature and lower-stratospheric water vapor concentrations in the tropics. The numerical accuracy of the vertical advection, determined in the MetUM by the choice of interpolation and conservation schemes used, is found to be particularly important. Microphysical and radiative processes are found to influence stratospheric water vapor both through modifying the tropical tropopause temperature and through modifying upper-tropospheric water vapor concentrations, allowing more water vapor to be advected into the stratosphere. The representation of any of the processes discussed can act to significantly reduce biases in tropical tropopause temperature and stratospheric water vapor in a physical way, thereby improving climate simulations

Genome-wide association study identifies loci associated with liability to alcohol and drug dependence that is associated with variability in reward-related ventral striatum activity in African- and European-Americans.

Genetic influences on alcohol and drug dependence partially overlap, however, specific loci underlying this overlap remain unclear. We conducted a genome-wide association study (GWAS) of a phenotype representing alcohol or illicit drug dependence (ANYDEP) among 7291 European-Americans (EA; 2927 cases) and 3132 African-Americans (AA: 1315 cases) participating in the family-based Collaborative Study on the Genetics of Alcoholism. ANYDEP was heritable (h 2 in EA = 0.60, AA = 0.37). The AA GWAS identified three regions with genome-wide significant (GWS; P < 5E-08) single nucleotide polymorphisms (SNPs) on chromosomes 3 (rs34066662, rs58801820) and 13 (rs75168521, rs78886294), and an insertion-deletion on chromosome 5 (chr5:141988181). No polymorphisms reached GWS in the EA. One GWS region (chromosome 1: rs1890881) emerged from a trans-ancestral meta-analysis (EA + AA) of ANYDEP, and was attributable to alcohol dependence in both samples. Four genes (AA: CRKL, DZIP3, SBK3; EA: P2RX6) and four sets of genes were significantly enriched within biological pathways for hemostasis and signal transduction. GWS signals did not replicate in two independent samples but there was weak evidence for association between rs1890881 and alcohol intake in the UK Biobank. Among 118 AA and 481 EA individuals from the Duke Neurogenetics Study, rs75168521 and rs1890881 genotypes were associated with variability in reward-related ventral striatum activation. This study identified novel loci for substance dependence and provides preliminary evidence that these variants are also associated with individual differences in neural reward reactivity. Gene discovery efforts in non-European samples with distinct patterns of substance use may lead to the identification of novel ancestry-specific genetic markers of risk

Genome-wide association scan meta-analysis identifies three Loci influencing adiposity and fat distribution.

To identify genetic loci influencing central obesity and fat distribution, we performed a meta-analysis of 16 genome-wide association studies (GWAS, N = 38,580) informative for adult waist circumference (WC) and waist-hip ratio (WHR). We selected 26 SNPs for follow-up, for which the evidence of association with measures of central adiposity (WC and/or WHR) was strong and disproportionate to that for overall adiposity or height. Follow-up studies in a maximum of 70,689 individuals identified two loci strongly associated with measures of central adiposity; these map near TFAP2B (WC, P = 1.9x10(-11)) and MSRA (WC, P = 8.9x10(-9)). A third locus, near LYPLAL1, was associated with WHR in women only (P = 2.6x10(-8)). The variants near TFAP2B appear to influence central adiposity through an effect on overall obesity/fat-mass, whereas LYPLAL1 displays a strong female-only association with fat distribution. By focusing on anthropometric measures of central obesity and fat distribution, we have identified three loci implicated in the regulation of human adiposity

A long view of liberal peace and its crisis

The ‘crisis’ of liberal peace has generated considerable debate in International Relations. However, analysis is inhibited by a shared set of spatial, cultural and temporal assumptions that rest on and reproduce a problematic separation between self-evident ‘liberal’ and ‘non-liberal’ worlds, and locates the crisis in presentist terms of the latter’s resistance to the former’s expansion. By contrast, this article argues that efforts to advance liberal rule have always been interwoven with processes of alternative order-making, and in this way are actively integral, not external, to the generation of the subjectivities, contestations, violence and rival social orders that are then apprehended as self-evident obstacles and threats to liberal peace and as characteristic of its periphery. Making visible these intimate relations of co-constitution elided by representations of liberal peace and its crisis requires a long view and an analytical frame that encompasses both liberalism and its others in the world. The argument is developed using a Foucauldian governmentality framework and illustrated with reference to Sri Lanka

Vessel-Associated Transforming Growth Factor-Beta1 (TGF-β1) Is Increased in the Bronchial Reticular Basement Membrane in COPD and Normal Smokers

BACKGROUND: Transforming growth factor-beta1 (TGF-β1) is a multipotential cytokine with angiogenic activity. There are only limited data about its role in airway remodeling in COPD. We have previously shown that the reticular basement membrane (Rbm) is hypervascular in the airways of current smokers either with or without chronic obstructive pulmonary disease (COPD). This study evaluated TGF-β1 immunostaining in the Rbm and its relationship to vascularity in smokers with or without COPD. METHODOLOGY/PRINCIPAL FINDINGS: Bronchial biopsies from 15 smokers with normal lung function, 19 current and 14 ex-smokers with COPD were immunostained for TGF-β1 antibody and compared to 17 healthy controls. The percentage area of tissue and also number and area of vessels staining positively for TGF-β1 were measured and compared between groups. Some bronchial biopsies from current smoking COPD subjects were also stained for phosphorylated (active) Smad2/3. Epithelial TGF- β1 staining was not different between COPD current smokers and normal controls. TGF-β1 stained vessels in the Rbm were increased in smokers with normal lung function, current smoking COPD and ex-smokers with COPD compared to controls [median (range) for number of vessels/mm Rbm 2.5 (0.0-12.7), 3.4 (0.0-8.1) and 1.0 (0.0-6.3) vs. 0.0 (0.0-7.0), p<0.05]. Percentage of vessels stained was also increased in these clinical groups. Preliminary data suggest that in current smoking COPD subjects endothelial cells and cells in the Rbm stain positively for phosphorylated Smad2/3 suggesting TGF-β1 is functionally active in this situation. CONCLUSIONS/SIGNIFICANCE: Vessel-associated TGF-β1 activity is increased in the bronchial Rbm in smokers and especially those with COPD