983 research outputs found

    Component-aware Orchestration of Cloud-based Enterprise Applications, from TOSCA to Docker and Kubernetes

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    Enterprise IT is currently facing the challenge of coordinating the management of complex, multi-component applications across heterogeneous cloud platforms. Containers and container orchestrators provide a valuable solution to deploy multi-component applications over cloud platforms, by coupling the lifecycle of each application component to that of its hosting container. We hereby propose a solution for going beyond such a coupling, based on the OASIS standard TOSCA and on Docker. We indeed propose a novel approach for deploying multi-component applications on top of existing container orchestrators, which allows to manage each component independently from the container used to run it. We also present prototype tools implementing our approach, and we show how we effectively exploited them to carry out a concrete case study

    Understanding the food water nexus: Characterizing the impact of climatological anomalies on agrosystems

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    Climate variability at global and regional scales is escalating with increased atmospheric carbon and is expected to magnify the intensity and duration of meteorological extremes, especially droughts. From the many environmental stresses that diminish crop production (e.g., soil salinity, frost, soil erosion) drought is one of the most prevalent. This study focuses on the sensitivity of three key crops produced in the northwestern United States to climatological anomalies, while controlling for attribution using anomalies in price. The study differs from similar studies in that we focus on variability in production which captures both yield (tonnes/ha) and cropping area (ha), as opposed to only yield. We use multivariate linear regression to determine the timing and time-scale of precipitation and PET anomalies most correlated with annual crop production anomalies, and develop sensitivity coefficients using Markov chain Monte- Carlo. Counties with similar sensitivity to precipitation, PET, and price were then clustered using k-means analysis. Alfalfa was most sensitive to both precipitation and PET anomalies, with as much as 93% and 81% of the precipitation and PET anomalies translating to the production anomaly. Barley was least sensitive. The timing of precipitation and PET anomalies were generally most important in June- August. The time-scale of precipitation and PET anomaly best correlated to production was variable, but generally greater than similar studies focusing on yield. Sensitivity to precipitation anomalies followed gradients in precipitation, temperature, and soil moisture regimes present across the study area. Our research provides simple models of climate effects on production at the county scale using public data which can be implemented by agricultural producers and decision makers to quantify the impacts of climatological and economic fluctuations on annual crop production

    Endoscopic optical coherence tomography with a flexible fiber bundle

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    We demonstrate in vivo endoscopic optical coherence tomography (OCT) imaging in the forward direction using a flexible fiber bundle. In comparison to current conventional forward looking probe schemes, our approach simplifies the endoscope design by avoiding the integration of any beam steering components in the distal probe end due to 2D scanning of a focused light beam over the proximal fiber bundle surface. We describe the challenges that arise when OCT imaging with a fiber bundle is performed, such as multimoding or cross-coupling. The performance of different fiber bundles with varying parameters such as numerical aperture, core size and core structure was consequently compared and artifacts that degrade the image quality were described in detail. Based on our findings, we propose an optimal fiber bundle design for endoscopic OCT imaging

    A Geochemical Analysis of Tosawihi Quarries Chert Using X-Ray Fluorescence Spectrometry

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    Lithic source analysis, or “sourcing,” is a geochemical compositional analysis of lithic materials for both major and trace elements. Sourcing analysis assigns lithic sources to geochemical groups according to distinct geochemical compositions, where unique elemental signatures represent separate lithic sources. In archaeological research, sourcing informs upon mobility strategies, trade and exchange networks, and lithic conveyance studies. While obsidian sourcing is a relatively reliable and popular technique, chert sourcing is more difficult and historically less successful largely due to variability in chert formation processes. X-ray fluorescence spectrometry (XRF) offers a possible sourcing technique, and is non-destructive, as well as time and cost-effective. In this thesis, I test the reliability of XRF in determining the geochemical characterization of Tosawihi Quarries chert, a unique chert source located in the Humboldt River Basin of north-central Nevada. The Tosawihi Quarries archaeological district (26EK6624) is a significant lithic resource that has hosted human occupation and activity for millennia. The Tosawihi Quarries offers a high quality toolstone that was intensely used, as indicated by numerous quarry locales and biface tool caches. Additionally, the Tosawihi Quarries is a social identity marker for the Tosawihi band of Western Shoshone, also serving as a source of spirituality and medicine. Tosawihi chert is a distinct, white lithic material type that also has a characteristic fluorescence pattern when exposed to ultraviolet light. While these are defining attributes, they are not unique to Tosawihi chert, as they occur in other Great Basin white chert sources. Identifying Tosawihi chert has been problematic, and misidentifications may have led to erroneous interpretations of the archaeological and ethnographic records. If successful, a geochemical characterization by XRF would provide an elemental signature specific to Tosawihi chert, thus eliminating discrepancies in visual and ultraviolet fluorescence readings and permitting archaeologists to accurately asses the distribution and use of this sacred material. In this thesis research, I first conducted an XRF analysis of a source standard collection of Tosawihi Quarries chert, which yielded a preliminary methodology for identifying Tosawihi chert. This protocol was tested against two comparative collections of other Great Basin white cherts: Mono Lake Spillway located in western Nevada and Pahute Mesa (26NY1408) located in southern Nevada. The methodology, now refined, was then run against the archaeological collection, where five collections of white chert artifacts were tested for the presence of Tosawihi chert. Incorporating both the qualitative and quantitative data from XRF analysis, the results show that this proposed methodology can successfully discriminate between Tosawihi chert and other Great Basin white cherts based on its XRF signature

    Complexities in the palaeoenvironmental and archaeological interpretation of isotopic analyses of the Mud Shell Geloina erosa (Lightfoot, 1786)

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    Isotope signals derived from molluscan shell carbonates allow researchers to investigate palaeoenvironments and the timing and periodicity of depositional events. However, it cannot be assumed that all molluscan taxa provide equally useful data owing to species-specific biological and ecological traits. The Mud Shell, Geloina erosa (Lightfoot, 1786) (syn. Polymesoda coaxans, syn. Polymesoda erosa), an infaunal mangrove bivalve, is a common component of archaeological deposits along Australia's tropical north coast and throughout the Indo-West Pacific. The ubiquity of G. erosa has led to numerous researchers incorporating this taxon into interpretations of associated deposits, particularly in the generation of radiocarbon chronologies and as a palaeoenvironmental proxy. Despite this, concerns have been expressed regarding the impact of G. erosa physiology and ecology on associated geochemical signals. Adaptations allowing the survival of this species within its highly changeable mangrove environment may introduce complexities into radiocarbon and environmental data archived within its shell. This study combines local environmental and hydrological data with isotopic analysis (δ18O, δ13C, and 14C) of live-collected specimens to explore the interpretability of geochemical proxies derived from G. erosa. Results suggest a number of factors may impact geochemical markers in unpredictable ways, eroding the usefulness of associated interpretations

    Savanna in equatorial Borneo during the late Pleistocene

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    Equatorial Southeast Asia is a key region for global climate change. Here, the Indo-Pacific Warm Pool (IPWP) is a critical driver of atmospheric convection that plays a dominant role in global atmospheric circulation. However, fluctuating sea-levels during the Pleistocene produced the most drastic land-sea area changes on Earth, with the now-drowned continent of Sundaland being exposed as a contiguous landmass for most of the past 2 million years. How vegetation responded to changes in rainfall that resulted from changing shelf exposure and glacial boundary conditions in Sundaland remains poorly understood. Here we use the stable carbon isotope composition (δ13C) of bat guano and High Molecular Weight n-alkanes, from Saleh Cave in southern Borneo to demonstrate that open vegetation existed during much the past 40,000 yrs BP. This location is at the southern equatorial end of a hypothesized ‘savanna corridor’ and the results provide the strongest evidence yet for its existence. The corridor would have operated as a barrier to east-west dispersal of rainforest species, and a conduit for north-south dispersal of savanna species at times of lowered sea level, explaining many modern biogeographic patterns. The Saleh Cave record also exhibits a strong correspondence with insolation and sea surface temperatures of the IPWP, suggesting a strong sensitivity of vegetation to tropical climate change on glacial/interglacial timeframes

    Explaining the imbalance in δ13C between soil and biomass in fire-prone tropical savannas

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    Currently, models of terrestrial 13C discrimination indicate that about one quarter of the gross primary productivity (GPP - total carbon fixed as biomass by plants) by the terrestrial biosphere is attributable to tropical savanna/grassland plants that use the C, photosynthetic pathway. However, the fraction of C,-derived biomass in soil organic carbon in savanna systems is much lower than these GPP estimates imply. Determining this imbalance has significant implications for correctly interpreting soil and palaeosol carbon isotope data, and for modelling studies that use variations in the atmospheric δ13CO, record to apportion sources and sinks of carbon. Here, we present preliminary results using hydrogen pyrolysis (HyPy) for quantifying the abundance and identifying the source of pyrogenic carbon (PC) in tropical savannas of North Queensland (Australia). We collected sediment from a series of micro-catchments covering the broadest possible range of C, and C, environments, and compared the abundances and stable isotope compositions of the total organic carbon (TOC) and pyrogenic carbon (PC) fractions. Hydrogen pyrolysis (HyPy) can be used to quantify the production, fate and stable isotope composition of PC produced by vegetation burning. HyPy is pyrolysis (up to ~600°C) under high hydrogen pressures (>10 MPa) in the presence of a catalyst, and when applied to sediments, soils, or organic samples results in the reductive removal of labile organic matter. Therefore, this technique offers great potential to effectively isolate and quantify pyrogenic carbon in a rapid and cost effective manner. Moreover, comparison of the stable carbon isotope composition of PC with bulk carbon has the potential to discern if there is a dominant vegetation source contributing to burning. The results indicate that the δ13C value of PC in the sediments is up 6‰ higher than the 613C value of TOC. There is a larger difference when TOC abundances in the sediments are lowest. This suggests a significant component of C,-derived PC is present in the sediments, even when the proportion of C, biomass in the catchment is relatively low. This in turn, provides evidence for the preferential combustion and transport of C4-derived PC in tropical savannas. Savanna fires preferentially burn the grass understorey rather than large trees, leading to a bias toward the finer C,-derived PC being exported from a fire and accumulated in the sedimentary record while large particles of Crderived PC are more likely to remain at the site of burning. Our preliminary data suggest that application of HyPy in environmental studies enables accurate quantification of an essential component of the terrestrial C cycle. Moreover, the use of HyPy also enables the reliable determination of the stable carbon isotope composition of PC, which will enable deeper understanding of the dynamic role of biomass burning in the global carbon cycle

    A global carbon and nitrogen isotope perspective on modern and ancient human diet

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    Stable carbon and nitrogen isotope analyses are widely used to infer diet and mobility in ancient and modern human populations, potentially providing a means to situate humans in global food webs. We collated 13,666 globally distributed analyses of ancient and modern human collagen and keratin samples. We converted all data to a common “Modern Diet Equivalent” reference frame to enable direct comparison among modern human diets, human diets prior to the advent of industrial agriculture, and the natural environment. This approach reveals a broad diet prior to industrialized agriculture and continued in modern subsistence populations, consistent with the human ability to consume opportunistically as extreme omnivores within complex natural food webs and across multiple trophic levels in every terrestrial and many marine ecosystems on the planet. In stark contrast, isotope dietary breadth across modern nonsubsistence populations has compressed by two-thirds as a result of the rise of industrialized agriculture and animal husbandry practices and the globalization of food distribution networks
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