3,733 research outputs found

    Hydrological controls of in situ preservation of waterlogged archaeological deposits

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    Environmental change caused by urban development, land drainage, agriculture or climate change may result in accelerated decay of in situ archaeological remains. This paper reviews research into impacts of environmental change on hydrological processes of relevance to preservation of archaeological remains in situ. It compares work at rural sites with more complex urban environments. The research demonstrates that both the quantity and quality of data on preservation status, and hydrological and chemical parameters collected during routine archaeological surveys need to be improved. The work also demonstrates the necessity for any archaeological site to be placed within its topographic and geological context. In order to understand preservation potential fully, it is necessary to move away from studying the archaeological site as an isolated unit, since factors some distance away from the site of interest can be important for determining preservation. The paper reviews what is known about the hydrological factors of importance to archaeological preservation and recommends research that needs to be conducted so that archaeological risk can be more adequately predicted and mitigated. Any activity that changes either source pathways or the dominant water input may have an impact not just because of changes to the water balance or the water table, but because of changes to water chemistry. Therefore, efforts to manage threatened waterlogged environments must consider the chemical nature of the water input into the system. Clearer methods of assessing the degree to which buried archaeological sites can withstand changing hydrological conditions are needed, in addition to research which helps us understand what triggers decay and what controls thresholds of response for different sediments and types of artefact

    A further analysis of the Verde River Watershed ecovalues: Working paper series--10-04

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    Located in central Arizona, the Verde River flows 170 miles through private property, state, tribal, and National Forest land. The river is the last remaining mostly free-flowing river in otherwise arid Arizona. The challenges facing the stakeholders of the river and its watershed are numerous and complex. The issues of population and industrial growth, drought and climate change all challenge the future of the watershed. As such it is necessary for the stakeholders of the watershed to gain an understanding of the importance (or lack thereof) of the watershed to their communities. Employing a data set created by West et al. (2009a and b), this study analyzes 35 interviews of stakeholders using a methodology developed by the Millennium Ecosystem Assessment (MEA, 2003). This study conducts a strategic environmental assessment by evaluating the open ended responses with regard to how the watershed services correspond to human well being. To the authors' knowledge, this is the first application of the MEA tool to link ecosystem services to human well being. The Verde River watershed provides much more value to society in terms of contributing to human well-being than simply a source for water. The access to water for a variety of uses is vitally important to the stakeholders within the watershed; however, myriad other aspects of the watershed are also very important to the same stakeholders. As the possible threats to the Verde River and its watershed increase at an increasing rate, the stakeholders need to address these threats

    Valuing the Verde River Watershed: An Assessment: Working Paper Series--09-03

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    This valuation study is designed to be the first phase of a larger series of studies to value the ecosystem services of the Verde River and its watershed. Interviews were conducted with 35 anonymous community leaders who live in, work with, or manage some aspect of the watershed (or a combination of the three). The interviews resulted in a large list of values for the watershed and provide a starting point for more studies. This report includes preliminary analysis of the data collected from these interviews, a brief literature review on ecosystem services, and recommendations for future research

    Defining the Regional and Seasonal Climatic Response of Long Douglas-Fir Tree-Ring Chronologies in Central Mexico

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    Problems with instrumental climate data and difficulties arising from the distribution of sensitive, long-term tree-ring chronologies across Mexico\u27s complex terrain have made it difficult to model the climate signal of tree-rings in Mexico. The objective of this research is to utilize the improved long-term, high-resolution, gridded instrumental climate dataset for Mexico recently developed by Zhu and Lettenmaier (2007) to document the climate signal of Douglas-fir in central Mexico. Through correlation analysis between five Douglas-fir tree-ring chronologies created by the University of Arkansas-Fayetteville Tree-Ring Laboratory and Zhu and Lettenmaier\u27s (2007) gridded historical climate dataset, this research aims to define the regional and seasonal precipitation signal of earlywood (EW) and latewood (LW) tree-ring chronologies and to create a regionally averaged time series that could be considered as a proxy of seasonal climate for specific regions of central Mexico. Monthly and seasonal analyses between the gridded data and the EW and LW tree-ring chronologies show that spring precipitation signal in EW is the strongest, especially at Cuauhtémoc la Fragua. Summer precipitation signal in LW is apparent, though the region of strong signal is smaller than for EW and spring. Cuauhtémoc la Fragua again displayed the best results for modeling regional climate signal in the LW. There was a modest amount of seasonal overlap in climate signal between EW and LW. Also, because the tree-ring chronologies come from sites at remote, high elevations, more high-elevation climate data might contribute to better overall modeling of precipitation signal in the Douglas-fir of central Mexico

    Cost-effectiveness of initial stress cardiovascular MR, stress SPECT or stress echocardiography as a gate-keeper test, compared with upfront invasive coronary angiography in the investigation and management of patients with stable chest pain: Mid-term outcomes from the CECaT randomised controlled trial

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    Objectives: To compare outcomes and cost-effectiveness of various initial imaging strategies in the management of stable chest pain in a long-term prospective randomised trial. Setting: Regional cardiothoracic referral centre in the east of England. Participants: 898 patients (69% man) entered the study with 869 alive at 2 years of follow-up. Patients were included if they presented for assessment of stable chest pain with a positive exercise test and no prior history of ischaemic heart disease. Exclusion criteria were recent infarction, unstable symptoms or any contraindication to stress MRI. Primary outcome measures: The primary outcomes of this follow-up study were survival up to a minimum of 2 years post-treatment, quality-adjusted survival and cost-utility of each strategy. Results: 898 patients were randomised. Compared with angiography, mortality was marginally higher in the groups randomised to cardiac MR (HR 2.6, 95% CI 1.1 to 6.2), but similar in the single photon emission CT-methoxyisobutylisonitrile (SPECT-MIBI; HR 1.0, 95% CI 0.4 to 2.9) and ECHO groups (HR 1.6, 95% CI 0.6 to 4.0). Although SPECT-MIBI was marginally superior to other non-invasive tests there were no other significant differences between the groups in mortality, quality-adjusted survival or costs. Conclusions: Non-invasive cardiac imaging can be used safely as the initial diagnostic test to diagnose coronary artery disease without adverse effects on patient outcomes or increased costs, relative to angiography. These results should be interpreted in the context of recent advances in imaging technology. Trial registration: ISRCTN 47108462, UKCRN 3696

    New Evidence on the Palaeobiology of the Eureka Sound Formation, Arctic Canada

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    The Eureka Sound Formation, a thick sedimentary unit in the Canadian Arctic having a late Cretaceous and/or early Tertiary age, is known to contain plant fossils indicative of a continental origin of deposition and a relatively temperate climate. The Formation was selected for a palaeontological survey in order to determine whether it could, as suggested by distribution of fossil vertebrates in other areas and from evidence of plate tectonics, provide evidence on terrestrial migrations between North America and Europe in the Palaeogene. Fossils of plants, invertebrates and fish were found. They indicated that large parts of the Formation are marine in origin, although other parts are continental and thus could still be interpreted as representing part of a land connection between the northern landmasses

    Microtubule depolymerization by the kinesin-8 motor Kip3p: a mathematical model

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    Proteins from the kinesin-8 family promote microtubule (MT) depolymerization, a process thought to be important for the control of microtubule length in living cells. In addition to this MT shortening activity, kinesin 8s are motors that show plus-end directed motility on MTs. Here we describe a simple model that incorporates directional motion and destabilization of the MT plus end by kinesin 8. Our model quantitatively reproduces the key features of length-vs-time traces for stabilized MTs in the presence of purified kinesin 8, including length-dependent depolymerization. Comparison of model predictions with experiments suggests that kinesin 8 depolymerizes processively, i.e., one motor can remove multiple tubulin dimers from a stabilized MT. Fluctuations in MT length as a function of time are related to depolymerization processivity. We have also determined the parameter regime in which the rate of MT depolymerization is length dependent: length-dependent depolymerization occurs only when MTs are sufficiently short; this crossover is sensitive to the bulk motor concentration.Comment: 34 pages, 11 figure

    A phase Ib/II study of cabozantinib (XL184) with or without erlotinib in patients with non-small cell lung cancer.

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    PurposeCabozantinib is a multi-kinase inhibitor that targets MET, AXL, and VEGFR2, and may synergize with EGFR inhibition in NSCLC. Cabozantinib was assessed alone or in combination with erlotinib in patients with progressive NSCLC and EGFR mutations who had previously received erlotinib.MethodsThis was a phase Ib/II study (NCT00596648). The primary objectives of phase I were to assess the safety, pharmacokinetics, and pharmacodynamics and to determine maximum tolerated dose (MTD) of cabozantinib plus erlotinib in patients who failed prior erlotinib treatment. In phase II, patients with prior response or stable disease with erlotinib who progressed were randomized to single-agent cabozantinib 100 mg qd vs cabozantinib 100 mg qd and erlotinib 50 mg qd (phase I MTD), with a primary objective of estimating objective response rate (ORR).ResultsSixty-four patients were treated in phase I. Doses of 100 mg cabozantinib plus 50 mg erlotinib, or 40 mg cabozantinib plus 150 mg erlotinib were determined to be MTDs. Diarrhea was the most frequent dose-limiting toxicity and the most frequent AE (87.5% of patients). The ORR for phase I was 8.2% (90% CI 3.3-16.5). In phase II, one patient in the cabozantinib arm (N = 15) experienced a partial response, for an ORR of 6.7% (90% CI 0.3-27.9), with no responses for cabozantinib plus erlotinib (N = 13). There was no evidence that co-administration of cabozantinib markedly altered erlotinib pharmacokinetics or vice versa.ConclusionsDespite responses with cabozantinib/erlotinib in phase I, there were no responses in the combination arm of phase II in patients with acquired resistance to erlotinib. Cabozantinib did not appear to re-sensitize these patients to erlotinib

    The patient experience with shared decision-making in lung cancer: A survey of patients, significant others or care givers

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    A survey (via SurveyMonkey) was sent to lung cancer patients, their caregivers or significant others asking about their experience in making difficult treatment decisions. Of the 198 respondents, 118 (69%) indicated that they had faced a difficult decision with respect to their lung cancer treatment. Of those, 73% indicated that they would have desired that the decision be made with their physician using a shared decision-making process, and 58% perceived that such a process had occurred. In addition, only 23% of respondents indicated that they had had the right amount of information when making the decision. Fortunately, only 9% of respondents expressed regret regarding the decision they ultimately made. A Patient Decision Aid (PDA) was made available to the respondents to view, and opinions were sought regarding the usefulness of this type of format for presenting information. This format was perceived as helpful, unsure if helpful, or not helpful by 62%, 36%, and 2% of respondents, respectively. In summary, the majority of lung cancer patients want to make difficult decisions using a shared decision-making process. The patient perception is that this is not occurring often enough. Even in this fairly well-educated group of respondents, many report that they are not sure that they have all the information necessary to make that difficult decision. Physicians may need help developing their communication and shared decision-making skills. Introducing PDAs into the oncology clinic may represent a way to present complex information and improve the patient experience

    eLISA Telescope In-field Pointing and Scattered Light Study

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    The orbital motion of the three spacecraft that make up the eLISA Observatory constellation causes long-arm line of sight variations of approximately one degree over the course of a year. The baseline solution is to package the telescope, the optical bench, and the gravitational reference sensor (GRS) into an optical assembly at each end of the measurement arm, and then to articulate the assembly. An optical phase reference is exchanged between the moving optical benches with a single mode optical fiber (backlink fiber). An alternative solution, referred to as in-field pointing, embeds a steering mirror into the optical design, fixing the optical benches and eliminating the backlink fiber, but requiring the additional complication of a two-stage optical design for the telescope. We examine the impact of an in-field pointing design on the scattered light performance
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