1,744 research outputs found

    Challenges and Benefits of Standardising Early Warning Systems: A Case Study of New Zealand’s Volcanic Alert Level System

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    Volcano early warning systems are used globally to communicate volcano-related information to diverse stakeholders ranging from specific user groups to the general public, or both. Within the framework of a volcano early warning system, Volcano Alert Level (VAL) systems are commonly used as a simple communication tool to inform society about the status of activity at a specific volcano. Establishing a VAL system that is effective for multiple volcanoes can be challenging, given that each volcano has specific behavioural characteristics. New Zealand has a wide range of volcano types and geological settings, including rhyolitic calderas capable of very large eruptions (>500 km3) and frequent unrest episodes, explosive andesitic stratovolcanoes, and effusive basaltic eruptions at both caldera and volcanic field settings. There is also a range in eruption frequency, requiring the VAL system to be used for both frequently active ‘open-vent’ volcanoes, and reawakening ‘closed-vent’ volcanoes. Furthermore, New Zealand’s volcanoes are situated in a variety of risk settings ranging from the Auckland Volcanic Field, which lies beneath a city of 1.4 million people; to Mt. Ruapehu, the location of popular ski fields that are occasionally impacted by ballistics and lahars, and produces tephra that falls in distant cities. These wide-ranging characteristics and their impact on society provide opportunities to learn from New Zealand’s experience with VAL systems, and the adoption of a standardised single VAL system for all of New Zealand’s volcanoes following a review in 2014. This chapter outlines the results of qualitative research conducted in 2010–2014 with key stakeholders and scientists, including from the volcano observatory at GNS Science, to ensure that the resulting standardised VAL system is an effective communication tool. A number of difficulties were faced in revising the VAL system so that it remains effective for all of the volcanic settings that exist in New Zealand. If warning products are standardised too much, end-user decision making and action can be limited when unusual situations occur, e.g., there may be loss of specific relevance in the alert message. Specific decision-making should be based on more specific parameters than the VAL alone, however wider VAL system standardisation can increase credibility, a known requirement for effective warning, by ensuring that warning sources are clear, trusted and widely understood. With a credible source, user groups are less likely to look for alternatives or confirmation, leading to faster action. Here we consider volcanic warnings within the wider concept of end-to-end multi-hazard early warning systems including detection, evaluation, notification, decision-making and action elements (based on Carsell et al. 2004)

    Gene expression profiling reveals different pathways related to Abl and other genes that cooperate with c-Myc in a model of plasma cell neoplasia

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    <p>Abstract</p> <p>Background</p> <p>To elucidate the genes involved in the neoplastic transformation of B cells, global gene expression profiles were generated using Affymetrix U74Av2 microarrays, containing 12,488 genes, for four different groups of mouse B-cell lymphomas and six subtypes of pristane-induced mouse plasma cell tumors, three of which developed much earlier than the others.</p> <p>Results</p> <p>Unsupervised hierarchical cluster analysis exhibited two main sub-clusters of samples: a B-cell lymphoma cluster and a plasma cell tumor cluster with subclusters reflecting mechanism of induction. This report represents the first step in using global gene expression to investigate molecular signatures related to the role of cooperating oncogenes in a model of Myc-induced carcinogenesis. Within a single subgroup, e.g., ABPCs, plasma cell tumors that contained typical T(12;15) chromosomal translocations did not display gene expression patterns distinct from those with variant T(6;15) translocations, in which the breakpoint was in the <it>Pvt-1 </it>locus, 230 kb 3' of c-<it>Myc</it>, suggesting that c-<it>Myc </it>activation was the initiating factor in both. When integrated with previously published Affymetrix array data from human multiple myelomas, the IL-6-transgenic subset of mouse plasma cell tumors clustered more closely with MM1 subsets of human myelomas, slow-appearing plasma cell tumors clustered together with MM2, while plasma cell tumors accelerated by v-Abl clustered with the more aggressive MM3-MM4 myeloma subsets. Slow-appearing plasma cell tumors expressed <it>Socs1 </it>and <it>Socs2 </it>but v-<it>Abl</it>-accelerated plasma cell tumors expressed 4–5 times as much. Both v-<it>Abl</it>-accelerated and non-v-<it>Ab</it>l-associated tumors exhibited phosphorylated STAT 1 and 3, but only v-Abl-accelerated plasma cell tumors lost viability and STAT 1 and 3 phosphorylation when cultured in the presence of the v-Abl kinase inhibitor, STI-571. These data suggest that the Jak/Stat pathway was critical in the transformation acceleration by v-Abl and that v-Abl activity remained essential throughout the life of the tumors, not just in their acceleration. A different pathway appears to predominate in the more slowly arising plasma cell tumors.</p> <p>Conclusion</p> <p>Gene expression profiling differentiates not only B-cell lymphomas from plasma cell tumors but also distinguishes slow from accelerated plasma cell tumors. These data and those obtained from the sensitivity of v-Abl-accelerated plasma cell tumors and their phosphorylated STAT proteins indicate that these similar tumors utilize different signaling pathways but share a common initiating genetic lesion, a c-<it>Myc</it>-activating chromosome translocation.</p

    Signatures of Majorana fermions in hybrid superconductor-semiconductor nanowire devices

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    Majorana fermions are particles identical to their own antiparticles. They have been theoretically predicted to exist in topological superconductors. We report electrical measurements on InSb nanowires contacted with one normal (Au) and one superconducting electrode (NbTiN). Gate voltages vary electron density and define a tunnel barrier between normal and superconducting contacts. In the presence of magnetic fields of order 100 mT we observe bound, mid-gap states at zero bias voltage. These bound states remain fixed to zero bias even when magnetic fields and gate voltages are changed over considerable ranges. Our observations support the hypothesis of Majorana fermions in nanowires coupled to superconductors.Comment: Raw data available at http://dx.doi.org/10.4121/uuid:8bf81177-2f2b-49c2-aaf5-d36739873dd

    Bilayer manganites: polarons in the midst of a metallic breakdown

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    The exact nature of the low temperature electronic phase of the manganite materials family, and hence the origin of their colossal magnetoresistant (CMR) effect, is still under heavy debate. By combining new photoemission and tunneling data, we show that in La{2-2x}Sr{1+2x}Mn2O7 the polaronic degrees of freedom win out across the CMR region of the phase diagram. This means that the generic ground state is that of a system in which strong electron-lattice interactions result in vanishing coherent quasi-particle spectral weight at the Fermi level for all locations in k-space. The incoherence of the charge carriers offers a unifying explanation for the anomalous charge-carrier dynamics seen in transport, optics and electron spectroscopic data. The stacking number N is the key factor for true metallic behavior, as an intergrowth-driven breakdown of the polaronic domination to give a metal possessing a traditional Fermi surface is seen in the bilayer system.Comment: 7 pages, 2 figures, includes supplementary informatio

    The influence of body weight on the pulmonary oxygen uptake kinetics in pre-pubertal children during moderate- and heavy intensity treadmill exercise

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    To assess the influence of obesity on the oxygen uptake (V˙O2) kinetics of pre-pubertal children during moderate- and heavy intensity treadmill exercise. We hypothesised that obese (OB) children would demonstrate significantly slower V˙O2 kinetics than their normal weight (NW) counterparts during moderate- and heavy intensity exercise. 18 OB (9.8 ± 0.5 years; 24.1 ± 2.0 kg m2) and 19 NW (9.7 ± 0.5 years; 17.6 ± 1.0 kg m2) children completed a graded-exercise test to volitional exhaustion and two submaximal constant work rate treadmill tests at moderate (90 % gas exchange threshold) and heavy (∆40 %) exercise intensities. Bodyweight significantly influenced the V˙O2 kinetics during both moderate- and heavy exercise intensities (P < 0.05). During moderate intensity exercise, the phase II τ (OB: 30 ± 13 cf. NW: 22 ± 7 s), mean response time (MRT; OB: 35 ± 16 cf. NW: 25 ± 10 s), phase II gain (OB: 156 ± 21 cf. NW: 111 ± 18 mLO2 kg−1 km−1) and oxygen deficit (OB: 0.36 ± 0.11 cf. NW: 0.20 ± 0.06 L) were significantly higher in the OB children (all P < 0.05). During heavy intensity exercise, the τ (OB: 33 ± 9 cf. NW: 27 ± 6 s; P < 0.05) and phase II gain (OB: 212 ± 61 cf. NW: 163 ± 23 mLO2 kg−1 km−1; P < 0.05) were similarly higher in the OB children. A slow component was observed in all participants during heavy intensity exercise, but was not influenced by weight status. In conclusion, this study demonstrates that weight status significantly influences the dynamic V˙O2 response at the onset of treadmill exercise in children and highlights that the deleterious effects of being obese are already manifest pre-puberty

    Treatment decisions and survival for people with small-cell lung cancer

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    Background: Chemotherapy improves survival for many patients with SCLC, and hence it is important to understand variations in practice and outcomes for this treatment strategy. Methods: We used the National Lung Cancer Audit and Hospital Episodes Statistics to determine the proportion of patients who received chemotherapy for SCLC, and assess the effects of patient and organisational factors on the odds of receiving chemotherapy and of completing four cycles. We calculated median survival and used Cox regression to determine factors that predicted survival. Results: Of 15 091 cases of SCLC, 70% received at least one cycle of chemotherapy. More deprived people were less likely to receive chemotherapy, but patients were more likely to receive chemotherapy, and to complete Xfour cycles, if they were referred to the lung cancer team by their GP. Median survival for those treated with chemotherapy was 12.9 months for limited and 7.3 months for extensive stage disease. Conclusions: The Linked NLCA and HES data provide real-life measures of survival in people treated with chemotherapy and show how this is influenced by patient and tumour characteristics. These data show the characteristics of patients who are less likely to complete a full course of treatment, an adverse predictor of survival

    The health system impact of false positive newborn screening results for medium-chain acyl-CoA dehydrogenase deficiency: A cohort study

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    Background - There is no consensus in the literature regarding the impact of false positive newborn screening results on early health care utilization patterns. We evaluated the impact of false positive newborn screening results for medium-chain acyl-CoA dehydrogenase deficiency (MCADD) in a cohort of Ontario infants. Methods - The cohort included all children who received newborn screening in Ontario between April 1, 2006 and March 31, 2010. Newborn screening and diagnostic confirmation results were linked to province-wide health care administrative datasets covering physician visits, emergency department visits, and inpatient hospitalizations, to determine health service utilization from April 1, 2006 through March 31, 2012. Incidence rate ratios (IRRs) were used to compare those with false positive results for MCADD to those with negative newborn screening results, stratified by age at service use. Results - We identified 43 infants with a false positive newborn screening result for MCADD during the study period. These infants experienced significantly higher rates of physician visits (IRR: 1.42) and hospitalizations (IRR: 2.32) in the first year of life relative to a screen negative cohort in adjusted analyses. Differences in health services use were not observed after the first year of life. Conclusions - The higher use of some health services among false positive infants during the first year of life may be explained by a psychosocial impact of false positive results on parental perceptions of infant health, and/or by differences in underlying health status. Understanding the impact of false positive newborn screening results can help to inform newborn screening programs in designing support and education for families. This is particularly important as additional disorders are added to expanded screening panels, yielding important clinical benefits for affected children but also a higher frequency of false positive findings.This study was Funded through a Canadian Institutes of Health Research (CIHR) Emerging Team Grant (TR3-119195). Maria Karaceper received a graduate scholarship through a charitable donation to the Children’s Hospital of Eastern Ontario. This study was performed at the Institute for Clinical Evaluative Sciences (ICES), which is funded by an annual grant from the Ontario Ministry of Health and Long-Term Care (MOHLTC)

    Use of horseradish peroxidase for gene-directed enzyme prodrug therapy with paracetamol

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    Gene therapy is a potential method of treating cancer with a greater degree of targeting than conventional therapies. In addition, therapy can be directed towards cells within the tumour population that are traditionally resistant to current treatment schedules. Horseradish peroxidase (HRP) can oxidise paracetamol to N-acetyl-p-benzoquinoneimine via a one-electron pathway. Incubation of human cells expressing HRP with 0.5–10 mm paracetamol reduced clonogenic survival, but had little effect on control cells. A small increase in apoptosis was seen and a decrease in the number of cells undergoing mitosis, consistent with reports in hepatocytes using higher paracetamol concentrations. The cytotoxicity was also seen under conditions of severe hypoxia (catalyst induced anoxia), indicating that the HRP/paracetamol combination may be suitable for hypoxia-targeted gene therapy
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