Improving the performance of HTTP over high bandwidth-delay product circuits

As the WWW continues to grow, providing adequate bandwidth to countries remote from the geographic and topological center of the network, such as those in the Asia/Pacific, becomes more and more difficult. To meet the growing traffic needs of the Internet some Network Service Providers are deploying satellite connections. Through discrete event simulation of a real HTTP workload with differing international architectures this paper is able to give guidance on the architecture that should be deployed for long distance, high capacity Internet links. We show that a significant increase in the time taken to fetch HTTP requests can be expected when traffic is moved from a long distance international terrestrial link to a satellite link. We then show several modifications to the network architecture that can be used to greatly improve the performance of a satellite link. These modifications include the use of an asymmetric satellite link, the multiplexing of multiple HTTP requests onto a single TCP connection and the use of HTTP1.1

Design of a processor to support the teaching of computer systems

Teaching computer systems, including computer architecture, assembly language programming and operating system implementation, is a challenging occupation. At the University of Waikato this is made doubly true because we require all computer science and information systems students study this material at second year. The challenges of teaching difficult material to a wide range of students have driven us to find ways of making the material more accessible. The corner stone of our strategy for delivering this material is the design and implementation of a custom CPU that meets the needs of teaching. This paper describes our motivation and these needs. We present the CPU and board design and describe the implementation of the CPU in an FPGA. The paper also includes some reflections on the use of a real CPU rather than a simulation environment. We conclude with a discussion of how the CPU can be used for advanced classes in computer architecture and a description of the current status of the project

The radial evolution of solar wind speeds

The WSA-ENLIL model predicts significant evolution of the solar wind speed. Along a flux tube the solar wind speed at 1.0 AU and beyond is found to be significantly altered from the solar wind speed in the outer corona at 0.1 AU, with most of the change occurring within a few tenths of an AU from the Sun. The evolution of the solar wind speed is most pronounced during solar minimum for solar wind with observed speeds at 1.0 AU between 400 and 500 km/s, while the fastest and slowest solar wind experiences little acceleration or deceleration. Solar wind ionic charge state observations made near 1.0 AU during solar minimum are found to be consistent with a large fraction of the intermediate-speed solar wind having been accelerated or decelerated from slower or faster speeds. This paper sets the groundwork for understanding the evolution of wind speed with distance, which is critical for interpreting the solar wind composition observations near Earth and throughout the inner heliosphere. We show from composition observations that the intermediate-speed solar wind (400-500 km/s) represents a mix of what was originally fast and slow solar wind, which implies a more bimodal solar wind in the corona than observed at 1.0 AU

Sublinear Estimation of Weighted Matchings in Dynamic Data Streams

This paper presents an algorithm for estimating the weight of a maximum weighted matching by augmenting any estimation routine for the size of an unweighted matching. The algorithm is implementable in any streaming model including dynamic graph streams. We also give the first constant estimation for the maximum matching size in a dynamic graph stream for planar graphs (or any graph with bounded arboricity) using $\tilde{O}(n^{4/5})$ space which also extends to weighted matching. Using previous results by Kapralov, Khanna, and Sudan (2014) we obtain a $\mathrm{polylog}(n)$ approximation for general graphs using $\mathrm{polylog}(n)$ space in random order streams, respectively. In addition, we give a space lower bound of $\Omega(n^{1-\varepsilon})$ for any randomized algorithm estimating the size of a maximum matching up to a $1+O(\varepsilon)$ factor for adversarial streams

Translesion Synthesis Polymerases in the Prevention and Promotion of Carcinogenesis

A critical step in the transformation of cells to the malignant state of cancer is the induction of mutations in the DNA of cells damaged by genotoxic agents. Translesion DNA synthesis (TLS) is the process by which cells copy DNA containing unrepaired damage that blocks progression of the replication fork. The DNA polymerases that catalyze TLS in mammals have been the topic of intense investigation over the last decade. DNA polymerase η (Pol η) is best understood and is active in error-free bypass of UV-induced DNA damage. The other TLS polymerases (Pol ι, Pol κ, REV1, and Pol ζ) have been studied extensively in vitro, but their in vivo role is only now being investigated using knockout mouse models of carcinogenesis. This paper will focus on the studies of mice and humans with altered expression of TLS polymerases and the effects on cancer induced by environmental agents

Health Benefits of Primary Care Social Work for Adults with Complex Health and Social Needs: A Systematic Review

The prevalence of complex health and social needs in primary care patients is growing. Furthermore, recent research suggests that the impact of psychosocial distress on the significantly poorer health outcomes in this population may have been underestimated. The potential of social work in primary care settings has been extensively discussed in both health and social work literature and there is evidence that social work interventions in other settings are particularly effective in addressing psychosocial needs. However, the evidence base for specific improved health outcomes related to primary care social work is minimal. This review aimed to identify and synthesise the available evidence on the health benefits of social work interventions in primary care settings. Nine electronic databases were searched from 1990 to 2015 and seven primary research studies were retrieved. Due to the heterogeneity of studies, a narrative synthesis was conducted. Although there is no definitive evidence for effectiveness, results suggest a promising role for primary care social work interventions in improving health outcomes. These include subjective health measures and self-management of long-term conditions, reducing psychosocial morbidity and barriers to treatment and health maintenance. Although few rigorous study designs were found, the contextual detail and clinical settings of studies provide evidence of the practice applicability of social work intervention. Emerging policy on the integration of health and social care may provide an opportunity to develop this model of care

Partisan Monetary Policies: Presidential Influence through the Power of Appointment

We investigate the channels through which partisan influence from a Presidential administration could affect monetary policy-making.Influence could be a result of direct Presidential pressure exerted on members of the Federal Open Market Committee (FOMC), or it could be a result of partisan considerations in Presidential appointments to the Board of Governors. To investigate these two channels of influence, we devise and apply a method for estimating parameters of monetary policy reaction functions that can vary across individual members of the FOMC Our results suggest that the appointments process is the primary mechanism by which partisan differences in monetary policies arise

Conservation Agriculture and Household Wellbeing: A Non-Causal Comparison among Smallholder Farmers in Mozambique

This research examines the relationship between household wellbeing and the use of conservation agriculture (CA) by smallholder farmers in Mozambique. Wellbeing indicators are regressed on household demographic attributes, farm management practices, and a variable indicating farmer adoption of CA. Findings suggest that households using CA have higher wellbeing index scores related to farm tool and implement ownership and housing material quality, but lower index scores related to livestock ownership. The findings present an encouraging, baseline picture of the association between the use of CA technologies by farmers in Mozambique and household wellbeing

Monetary Policy Preferences of Individual FOMC Members: A Content Analysis of the Memoranda of Discussion

The Memoranda of Discussion provide detailed records of Federal Open Market Committee (FOMC) meeting deliberations. Procedures are developed for coding the textual data in the Memoranda and assessing the reliability of those codings. The codings are then used in the estimation of parameters of individual FOMC members\u27 reaction functions. Data from the 1970 to 1976 period are employed in the estimation. In the future, similar methods could be used to analyze newly released transcripts of FOMC meetings held after 1976

Endogeneous Kinase Activity of Heterogeneous Ribonucleoprotein Particles

The aim of this work was to investigate a protein kinase activity found associated with hnRNP particles from rat liver nuclei. The location of this enzyme activity coupled with the known role of protein kinases in controlling other cellular events has led to the suggestion that an hnRNP associated kinase might influence the maturation of hnRNA to mRNA. HnRNP particles were isolated from purified rat liver nuclei by the method of Samarina et al., (1968) and further purified by centrifugation on 15-30% w/v sucrose density gradients. When analysed on a 2-dimensional fractionation system, which employed non-equilibrated pH gradients in the first dimension and SDS polyacrylamide gels in the second, hnRNP particles exhibited a heterogeneous protein profile dominated by the core proteins which appeared as chains of spots showing charge heterogeneity. Isolated hnRNP particles exhibited an endogenous protein kinase activity which was capable of phosphorylating added casein or histone but also phosphorylated hnRNP particle proteins. V/hen the proteins which had been subjected to in vitro phosphorylation were separated on 2-dimensional gels it was seen that the more acidic species in the chains of core proteins were phosphorylated. Evidence/ Evidence for the association of the protein kinase with 40S hnRNP particles came from the fact that a peak of kinase activity coincided with the 40S peak of hnRNP from sucrose density gradients and was still associated with the particles when hnRNP were isolated from one gradient and rerun on a second sucrose gradient. Kinase activity was still found associated with the particles even after gel filtration on a Bio Gel column although losses of kinase activity suggest that the enzyme is only loosely bound. A band of kinase activity corresponding to the stained hnRNP band was detected on non-denaturing polyacrylamide gels. The fractionation of hnRNP particle proteins to yield reasonable quantities of purified proteins is not easy as the proteins have strong affinities for each other. HnRNP particles could be completely dissociated with high salt concentrations. However dissociation was partially reversible and removal of salt led to reaggregation of a substantial percentage of the proteins. In order to try to fractionate hnRNP particle proteins, the particles were treated with 1M NaCl before being loaded on to a Sephadex G100 column in the presence of 1M NaCl. When the fractions from the column were analysed for protein kinase, 2 peaks of activity were seen - 'A' and 'B'. Both peaks contained a different set of polypeptides as seen on SDS polyacrylamide gels, and although 'A' and 'B' had similar pH, Mg2+ , time and temperature profiles their response to Mn2+ and their substrate specificity appeared to differ