487 research outputs found

    Attitudes to investment risk amongst West Midland canal and railway company investors, 1760-1850

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    Attitudes to environmental and investment risk are examined to determine whether they were a defining characteristic of middle-class behaviour in the period 1760 to 1850. Approximately 6,000 investors in eleven canal companies and seven railway companies were investigated to determine whether evaluation and mitigation of investment risk is determined by socio-economic background and gender. Investment risk was defined as inadequate access to, and imperfect interpretation of, information. The effectiveness of information transfer through public and private spheres was examined and the effect of differential access to these information conduits, as a consequence of gender or socio-economic background, was investigated. Investors' response to the risk environment of early death, war and unpredictable economic cycles was examined. Each canal company and the group of railway companies was ranked according to the level of investment risk during both the construction and operating period, using a mix of quantitative and qualitative tests. The risk preferences of 'economic' and 'financial' investors were compared. The strategies used by each group of investor to mitigate risk were examined. The study provides new evidence of the effective transmission of national market sentiment by the 1770s, but reveals that the physical market in canal company shares remained local and continued its separate existence long after the institutionalised national market for railway shares was established. Perceptible differences in the risk assessment and risk mitigation strategies of different groups of investors were observed. This was attributed to differential access to information, which in turn was attributed to gender and social, political and religious affiliation. The study provides evidence that although differences in behaviour were observed amongst groups within the sample population, it shared common investment strategies and that attitudes to risk and risk mitigation should be considered as valid criteria for class differentiation

    The effects of social structure and sex-biased transmission on macroparasite infection

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    Mathematical models of disease dynamics tend to assume that individuals within a population mix at random and so transmission is random, and yet, in reality social structure creates heterogeneous contact patterns. We investigated the effect of heterogeneity in host contact patterns on potential macroparasite transmission by first quantifying the level of assortativity in a socially structured wild rodent population (Apodemus flavicollis) with respect to the directly-transmitted macroparasitic helminth, Heligmosomoides polygyrus. We found the population to be disassortatively mixed (i.e. male mice mixing with female mice more often than same sex mixing) at a constant level over time. The macroparasite H. polygyrus has previously been shown to exhibit male-biased transmission so we used a Susceptible-Infected (SI) mathematical model to simulate the effect of increasing strengths of male-biased transmission on the prevalence of the macroparasite using empirically-derived transmission networks. When transmission was equal between the sexes the model predicted macroparasite prevalence to be 73% and infection was male biased (82% of infection in the male mice). With a male-bias in transmission ten times that of the females, the expected macroparasite prevalence was 50% and was equally prevalent in both sexes, results that both most closely resembled empirical dynamics. As such, disassortative mixing alone did not produce macroparasite dynamics analogous to those from empirical observations; a strong male-bias in transmission was also required. We discuss the relevance of our results in the context of network models for transmission dynamics and control

    Developing Herd Health Education for and Assessing Risky Practices of Cow-Calf Producers

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    Bovine respiratory disease (BRD) is an often unrecognized problem in cow-calf herds. We describe a program we used to help producers identify and avoid practices that could increase their herds\u27 risk for BRD. The greatest knowledge gains occurred for the topics of costs associated with BRD, BRD risks at the feedlot, and biosecurity measures. Through producer self-assessments, we found that the number of risky practices conducted by producers ranged from none to 22 per operation, averaging 10 per operation. Extension professionals should consider combining producer self-assessment with education on management as an effective strategy for informing producers of risks in their operations

    Breaking beta: deconstructing the parasite transmission function

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    Transmission is a fundamental step in the life cycle of every parasite but it is also one of the most challenging processes to model and quantify. In most host–parasite models, the transmission process is encapsulated by a single parameterβ. Many different biological processes and interactions, acting on both hosts and infectious organisms, are subsumed in this single term. There are, however, at least two undesirable consequences of this high level of abstraction. First, nonlinearities and heterogeneities that can be critical to the dynamic behaviour of infections are poorly represented; second, estimating the transmission coefficientβfrom field data is often very difficult. In this paper, we present a conceptual model, which breaks the transmission process into its component parts. This deconstruction enables us to identify circumstances that generate nonlinearities in transmission, with potential implications for emergent transmission behaviour at individual and population scales. Such behaviour cannot be explained by the traditional linear transmission frameworks. The deconstruction also provides a clearer link to the empirical estimation of key components of transmission and enables the construction of flexible models that produce a unified understanding of the spread of both micro- and macro-parasite infectious disease agents

    Peste des petits ruminants virus transmission scaling and husbandry practices that contribute to increased transmission risk: an investigation among sheep, goats, and cattle in Northern Tanzania

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    Peste des petits ruminants virus (PPRV) causes an infectious disease of high morbidity and mortality among sheep and goats which impacts millions of livestock keepers globally. PPRV transmission risk varies by production system, but a deeper understanding of how transmission scales in these systems and which husbandry practices impact risk is needed. To investigate transmission scaling and husbandry practice-associated risk, this study combined 395 household questionnaires with over 7115 cross-sectional serosurvey samples collected in Tanzania among agropastoral and pastoral households managing sheep, goats, or cattle (most managed all three, n = 284, 71.9%). Although self-reported compound-level herd size was significantly larger in pastoral than agropastoral households, the data show no evidence that household herd force of infection (FOI, per capita infection rate of susceptible hosts) increased with herd size. Seroprevalence and FOI patterns observed at the sub-village level showed significant spatial variation in FOI. Univariate analyses showed that household herd FOI was significantly higher when households reported seasonal grazing camp attendance, cattle or goat introduction to the compound, death, sale, or giving away of animals in the past 12 months, when cattle were grazed separately from sheep and goats, and when the household also managed dogs or donkeys. Multivariable analyses revealed that species, production system type, and goat or sheep introduction or seasonal grazing camp attendance, cattle or goat death or sales, or goats given away in the past 12 months significantly increased odds of seroconversion, whereas managing pigs or cattle attending seasonal grazing camps had significantly lower odds of seroconversion. Further research should investigate specific husbandry practices across production systems in other countries and in systems that include additional atypical host species to broaden understanding of PPRV transmission

    The characteristics of solar x-class flares and CMEs: a paradigm for stellar superflares and eruptions?

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    This paper explores the characteristics of 42 solar X-class flares that were observed between February 2011 and November 2014, with data from the Solar Dynamics Observatory (SDO) and other sources. This flare list includes nine X-class flares that had no associated CMEs. In particular our aim was to determine whether a clear signature could be identified to differentiate powerful flares that have coronal mass ejections (CMEs) from those that do not. Part of the motivation for this study is the characterization of the solar paradigm for flare/CME occurrence as a possible guide to the stellar observations; hence we emphasize spectroscopic signatures. To do this we ask the following questions: Do all eruptive flares have long durations? Do CME-related flares stand out in terms of active-region size vs. flare duration? Do flare magnitudes correlate with sunspot areas, and, if so, are eruptive events distinguished? Is the occurrence of CMEs related to the fraction of the active-region area involved? Do X-class flares with no eruptions have weaker non-thermal signatures? Is the temperature dependence of evaporation different in eruptive and non-eruptive flares? Is EUV dimming only seen in eruptive flares? We find only one feature consistently associated with CME-related flares specifically: coronal dimming in lines characteristic of the quiet-Sun corona, i.e. 1 – 2 MK. We do not find a correlation between flare magnitude and sunspot areas. Although challenging, it will be of importance to model dimming for stellar cases and make suitable future plans for observations in the appropriate wavelength range in order to identify stellar CMEs consistently

    Rac1 as a therapeutic target in ovarian cancer

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    Rac1 is a high value therapeutic target for cancer based on its tumor promoting activities, yet clinical applications targeting Rac1 are in their infancy. High expression and hyperactivation of Rac1 in ovarian cancer, along with our identification of R-ketorolac as a novel Rac1 and Cdc42 selective inhibitor with translational potential, prompt us to test the hypothesis that targeting Rac1 has therapeutic utility for ovarian cancer. Ascites tumor cell samples from ovarian cancer patients in a prospective study receiving racemic ketorolac for clinically indicated use in pain relief were previously reported to show time dependent reduction of Rac1 and Cdc42 activities post-treatment. New RNA seq data of these patient samples reveals significant changes of genes involved in cell adhesion, cytokine-mediated signaling and cytokine production pathways. Conversely, the identified downregulated genes were overexpressed and associated with worse survival in ovarian cancer patients analyzed through The Cancer Genome Atlas (TCGA). Among the downregulated genes in the NOD pathway are chemokines and pro-inflammatory cytokines. Follow-up cytokine panels from patients confirm that racemic ketorolac treatment reduces the levels of immunosuppressive cytokines IL-6, IL-10 and RANTES in ascites fluids. Together, these data indicate there may be a benefit to the anti-inflammatory activity of the S- enantiomer, as well as the GTPase inhibitory activity of the R- enantiomer of ketorolac for ovarian cancer treatment
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