Pair Formation within Multi-Agent Populations

We present a simple model for the formation of pairs in multi-agent populations of type A and B which move freely on a spatial network. Each agent of population A (and B) is labeled as Ai (and Bj) with i=1,.. NA (and j=1,..NB) and carries its own individual list of characteristics or 'phenotype'. When agents from opposite populations encounter one another on the network, they can form a relationship if not already engaged in one. The length of time for which any given pair stays together depends on the compatibility of the two constituent agents. Possible applications include the human dating scenario, and the commercial domain where two types of businesses A and B have members of each type looking for a business partner, i.e. Ai+Bj-->Rij. The pair Rij then survives for some finite time before dissociating Rij-->Ai+Bj. There are many possible generalizations of this basic setup. Here we content ourselves with some initial numerical results for the simplest of network topologies, together with some accompanying analytic analysis.Comment: Special Issue on Complex Networks, edited by Dirk Helbin

Efficacy and Cost Effectiveness of Adjuvant Chemotherapy in Women with Node-Negative Breast Cancer — A Decision-Analysis Model

Abstract BACKGROUND. In 1988 the National Cancer Institute issued a Clinical Alert that has been widely interpreted as recommending that all women with node-negative breast cancer receive adjuvant chemotherapy. Acceptance of this recommendation is controversial, since many women who would not have a recurrence would be treated. METHODS. Using a decision-analysis model, we studied the cost effectiveness of chemotherapy in cohorts of 45-year-old and 60-year-old women with node-negative breast cancer by calculating life expectancy as adjusted for quality of life. The analysis evaluated different scenarios of the benefit of therapy: improved disease-free survival for five years, with a lesser effect on overall survival (base line); a lifelong benefit from chemotherapy; and a benefit in disease-free survival with no change in overall survival by year 10. The base-line analysis assumed a 30 percent reduction in the relative risk of recurrence for five years after treatment. RESULTS. For the 45-year-old woman, the base-line analysis found an average lifetime benefit from chemotherapy of 5.1 quality-months at a cost of $15,400 per quality-year. The 60-year-old women gained 4.0 quality-months at a cost of$18,800 per quality-year. Under the more and less optimistic scenarios, the benefit of chemotherapy varied from 1.4 to 14.0 quality-months for both groups. CONCLUSIONS. Chemotherapy substantially increases the quality-adjusted life expectancy of an average woman at a cost comparable to that of other widely accepted therapies. This benefit decreases markedly if the changes in long-term survival are less than in disease-free survival. Given its uncertain duration, the benefit may be too small for many women to choose chemotherapy. Selective use of chemotherapy to maximize the benefit to individual patients may be possible with refinements in risk stratification and explicit assessment of the patients\u27 risk preferences. (N Engl J Med 1991; 324:160–8.

Modelling Social Structures and Hierarchies in Language Evolution

Language evolution might have preferred certain prior social configurations over others. Experiments conducted with models of different social structures (varying subgroup interactions and the role of a dominant interlocutor) suggest that having isolated agent groups rather than an interconnected agent is more advantageous for the emergence of a social communication system. Distinctive groups that are closely connected by communication yield systems less like natural language than fully isolated groups inhabiting the same world. Furthermore, the addition of a dominant male who is asymmetrically favoured as a hearer, and equally likely to be a speaker has no positive influence on the disjoint groups.Comment: 14 pages, 3 figures, 1 table. In proceedings of AI-2010, The Thirtieth SGAI International Conference on Innovative Techniques and Applications of Artificial Intelligence, Cambridge, England, UK, 14-16 December 201

Automatic annotation of bioinformatics workflows with biomedical ontologies

Legacy scientific workflows, and the services within them, often present scarce and unstructured (i.e. textual) descriptions. This makes it difficult to find, share and reuse them, thus dramatically reducing their value to the community. This paper presents an approach to annotating workflows and their subcomponents with ontology terms, in an attempt to describe these artifacts in a structured way. Despite a dearth of even textual descriptions, we automatically annotated 530 myExperiment bioinformatics-related workflows, including more than 2600 workflow-associated services, with relevant ontological terms. Quantitative evaluation of the Information Content of these terms suggests that, in cases where annotation was possible at all, the annotation quality was comparable to manually curated bioinformatics resources.Comment: 6th International Symposium on Leveraging Applications (ISoLA 2014 conference), 15 pages, 4 figure

Transcriptional regulation of bacterial virulence gene expression by molecular oxygen and nitric oxide

© Jeffrey Green, Matthew D Rolfe, and Laura J Smith. Molecular oxygen (O2) and nitric oxide (NO) are diatomic gases that play major roles in infection. The host innate immune system generates reactive oxygen species and NO as bacteriocidal agents and both require O2 for their production. Furthermore, the ability to adapt to changes in O2 availability is crucial for many bacterial pathogens, as many niches within a host are hypoxic. Pathogenic bacteria have evolved transcriptional regulatory systems that perceive these gases and respond by reprogramming gene expression. Direct sensors possess iron-containing co-factors (iron-sulfur clusters, mononuclear iron, heme) or reactive cysteine thiols that react with O2 and/or NO. Indirect sensors perceive the physiological effects of O2 starvation. Thus, O2 and NO act as environmental cues that trigger the coordinated expression of virulence genes and metabolic adaptations necessary for survival within a host. Here, the mechanisms of signal perception by key O2and NO-responsive bacterial transcription factors and the effects on virulence gene expression are reviewed, followed by consideration of these aspects of gene regulation in two major pathogens, Staphylococcus aureus and Mycobacterium tuberculosis

Peginterferon alfa-2a plus ribavirin for chronic hepatitis C virus infection.

BACKGROUND Treatment with peginterferon alfa-2a alone produces significantly higher sustained virologic responses than treatment with interferon alfa-2a alone in patients with chronic hepatitis C virus (HCV) infection. We compared the efficacy and safety of peginterferon alfa-2a plus ribavirin, interferon alfa-2b plus ribavirin, and peginterferon alfa-2a alone in the initial treatment of chronic hepatitis C. METHODS A total of 1121 patients were randomly assigned to treatment and received at least one dose of study medication, consisting of 180 μg of peginterferon alfa-2a once weekly plus daily ribavirin (1000 or 1200 mg, depending on body weight), weekly peginterferon alfa-2a plus daily placebo, or 3 million units of interferon alfa-2b thrice weekly plus daily ribavirin for 48 weeks. RESULTS A significantly higher proportion of patients who received peginterferon alfa-2a plus ribavirin had a sustained virologic response (defined as the absence of detectable HCV RNA 24 weeks after cessation of therapy) than of patients who received interferon alfa-2b plus ribavirin (56 percent vs. 44 percent, P CONCLUSIONS In patients with chronic hepatitis C, once-weekly peginterferon alfa-2a plus ribavirin was tolerated as well as interferon alfa-2b plus ribavirin and produced significant improvements in the rate of sustained virologic response, as compared with interferon alfa-2b plus ribavirin or peginterferon alfa-2a alone

Childhood IQ and social factors on smoking behaviour, lung function and smoking-related outcomes in adulthood: linking the Scottish Mental Survey 1932 and the Midspan studies

OBJECTIVE: To investigate the associations of childhood IQ and adult social factors, and smoking behaviour, lung function (forced expiratory volume in one second; FEV(1)), and smoking-related outcomes in adulthood. DESIGN: Retrospective cohort study. METHOD: Participants were from the Midspan prospective studies conducted on Scottish adults in the 1970s. The sample consisted of 938 Midspan participants born in 1921 who were successfully matched with their cognitive ability test results on the Scottish Mental Survey 1932. RESULTS: Structural equation modelling showed that age 11 IQ was not directly associated with smoking consumption, but that IQ and adult social class had indirect effects on smoking consumption via deprivation category. The influence of IQ on FEV(1) was partly indirect via social class. Gender influenced smoking consumption and also IQ and social class. There was a 21% higher risk of having a smoking-related hospital admission, cancer, or death during 25 years of follow-up for each standard deviation disadvantage in IQ. Adjustment for adult social class, deprivation category, and smoking reduced the association to 10%. CONCLUSION: Childhood IQ was associated with social factors which influenced lung function in adulthood, but was not associated directly with smoking consumption. In future studies, it is important to consider other pathways which may account for variance in the link between childhood IQ and health in later life

Investigating factors that influence cyclone mitigation behaviour: a pilot study

In cyclone-prone regions like North Queensland, insurance premiums are priced to reflect the high potential for economic loss from cyclone events. To address premium affordability, insurance companies (e.g., Suncorp) have begun offering their customers discounts for installing or performing mitigation measures aimed at reducing property damage. However, there is still a significant at-risk population who choose not to invest in mitigation measures. It is therefore important to further understand factors that facilitate or impede an individual's decision to invest in cyclone mitigation measures (e.g., experience, risk perception and perceptions about mitigation measures), so that preparedness messaging and incentive programs can be optimised for the population in which they are to be delivered. In 2016, James Cook University (HABITT and Cyclone Testing Station), Suncorp and the Queensland Government commenced a research project to investigate factors that influence mitigation behaviour. This presentation reviews findings from the first project study, which investigated the results from a pilot study of a self-administered questionnaire. The pilot study was delivered at an annual community cyclone awareness event in Townsville ("Cyclone Sunday"). A total of 72 respondents were recruited at the event and asked to complete the questionnaire assessing variables hypothesised to be of interest including age, homeownership, perceptions of risk and cyclone mitigation status. Preliminary data from the pilot study suggest that respondents tended to perceive future cyclone related property damage as likely but not severe. It was also found that while relatively low-cost preparedness activities were commonly performed, few respondents had installed more costly mitigation measures specifically aimed at reducing cyclone related property damage (e.g., cyclone shutters). The pilot study findings provide needed insight for the Phase I study into psychological drivers of cyclone mitigation behaviour which will take place later this year

The ‘hell of modern sound’ : a history of urban noise in modern Japan

Contemporary Japan is loud. Many scholars have argued that the Japanese have a cultural propensity to embrace urban noise. Yet little research has been done on the history of urban noise in Japan. Far from passively accepting or culturally embracing noisy cities, the Japanese have long struggled with the definition, measurement, and control of unwanted sound. Urban noise and the idea of the ‘modern’ soundscape have often worked within a feedback loop that amplifies politically driven debates about the nature of ‘modernity’, the meaning of ‘civilisation’, and the nature of the Japanese people. Since the late nineteenth century, authorities’ concern for urban noise stemmed from a fear of embarrassment because of the low level of ‘civilisation’ amongst the people. Yet rapid industrial development and urban population growth soon posed the problem of urban noise as one of technological expertise—the people were too backward to understand and the issue was best solved by the experts. As groups of scientists, engineers, and acousticians began to come together to debate solutions, they foregrounded urban noise as a problem of traffic, transport, and civic construction, not individual everyday life. Noisy neighbours, street noise, or people going about their daily business came to be heard as ‘urban music’ in contrast to ‘urban noise’. After 1945, better technological possibilities for soundproofing and an increasing focus on individual responsibility refocused urban noise as a problem of everyday life. With the end of the period of rapid economic growth in the 1970s, and the growing awareness of wider environmental problems, the noise of everyday life in the cities was gradually recast as one element of ‘urban noise’

Integral field spectroscopy of H-2 and CO emission in IRAS 18276-1431 : evidence for ongoing post-AGB mass-loss

The definitive version can be found at: http://www.wiley.com/ Copyright Wiley BlackwellWe present K-band integral field spectroscopy of the bipolar post-asymptotic giant branch (post-AGB) object IRAS 18276-1431 (OH 17.7-2.0) using SINFONI on the VLT. This allows us to image both the continuum and molecular features in this object from 1.95 to 2.45 mu m with a spatial resolution down to 70 mas and a spectral resolution of similar to 5000. We detect a range of H-2 rovibrational emission lines which are consistent with shock excitation in regions of dense (similar to 10(7) cm(-3)) gas with shock velocities in the range of 25-30 km s(-1). The distribution of H-2 emission in the bipolar lobes suggests that a fast wind is impinging on material in the cavity walls and tips. H-2 emission is also seen along a line of sight close to the obscured star as well as in the equatorial region to either side of the stellar position which has the appearance of a ring with radius 0.3 arcsec. This latter feature may be radially cospatial with the boundary between the AGB and post-AGB winds. The first overtone (CO)-C-12 bandheads are observed longward of 2.29 mu m with the v = 2-0 bandhead prominently in emission. The CO emission has the same spatial distribution as the K-band continuum and therefore originates from an unresolved central source close to the star. We interpret this as evidence for ongoing mass-loss in this object. This conclusion is further supported by a rising K-band continuum indicating the presence of warm dust close to the star, possibly down to the condensation radius. The redshifted scattered peak of the CO bandhead is used to estimate a dust velocity along the bipolar axis of 95 km s(-1) for the collimated wind. This places a lower limit of similar to 125 yr on the age of the bipolar cavities, meaning that the collimated fast wind turned on very soon after the cessation of AGB mass-loss.Peer reviewe