9,788 research outputs found

    Fire and Beyond: a Geoarchaeological Analysis of the Anthropogenic Features from Fumane Cave (NE Italy) and Hohle Fels (SW Germany)

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    Anthropogenic features provide direct evidence of human activities that took place during the occupation of a site and as such are valuable sources of information for inferring past behaviour. Their identification and interpretation is essential for archaeological research, and geoarchaeology has the potential to unravel their nature and place them into context. One of the main goals in the analysis of archaeological features is to investigate the relationship between humans and fire. A major issue in the investigation of human evolution and pyrotechnology is that fire and the ability to produce it are seen by some as one of the primary characteristics that distinguish modern humans from Neanderthals. Around this main debate, other threads open up. In fact, features like hearths can also provide insights into site maintenance, social organization, and settlement dynamics. Here I investigate the anthropogenic features from two important Palaeolithic caves in Europe, Fumane Cave (IT) and Hohle Fels (DE). Both sites cover the transition from the Middle to Upper Palaeolithic, providing the unique opportunity to explore Neanderthal and modern human settlements. First, I analysed the thin sections using micromorphology to understand the nature of the features and their link to human activities. Second, I obtained complete information by applying complementary analyses to selected samples. Third, I executed experimental work on burning bones in a controlled environment to understand better changes in bones heated at low temperatures. The results show a diverse set of anthropogenic features such as hearths, hearth bases, dumps, occupational horizons and laminated/trampled surfaces. Their presence reflects different activities, including combustion and site maintenance/use, carried out by humans within the site. Further, I infer fuel choice, occupation of sites and the mobility of the groups that inhabited them. Fumane Cave and Hohle Fels appear as a complex system of human behaviour based on a close relationship with the surrounding landscape. Finally, experimentation on charred bones reveals the potential of organic petrology in investigating fat-derived char and determining a range of combustion temperatures. This dissertation shows the importance of a micro-contextual approach within archaeological research, the potential of the investigation of anthropogenic features to reconstruct past human activities, and the need to consider them part of the cultural material. An anthropogenic feature is comparable to many other artefacts and must be treated as such to gain information on both natural processes and human behaviour

    On farm and off-farm feed utilization and improved management options: A Synthesis

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    The challenges identified in the proposal of the CGIAR Research Program (CRP) on Livestock, for enhancing livestock production and productivity, have been the shortage of quality feeds, inefficient utilization of feed resources, degradation of rangelands, and lack of knowledge and skills of stakeholders in the feed production and utilization value chains. To address these challenges, the research and development work, innovations developed and tested, results-dissemination and concerted efforts towards capacity building have been presented in the following three main sections. 1) Enlarging the feed quality resource base 2) Efficient use of feed resources 3) Rehabilitation of degraded rangeland

    Quantum walk in stochastic environment

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    We consider a quantized version of the Sinai-Derrida model for "random walk in random environment". The model is defined in terms of a Lindblad master equation. For a ring geometry (a chain with periodic boundary condition) it features a delocalization-transition as the bias in increased beyond a critical value, indicating that the relaxation becomes under-damped. Counter intuitively, the effective disorder is enhanced due to coherent hopping. We analyze in detail this enhancement and its dependence on the model parameters. The non-monotonic dependence of the Lindbladian spectrum on the rate of the coherent transitions is highlighted.Comment: 11 pages, 8 figure

    Duality in the directed landscape and its applications to fractal geometry

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    Due to the ubiquitous phenomenon of coalescence observed in random geometry, the union of interiors of all geodesics going to a fixed point tends to form a tree-like structure which is supported on a vanishing fraction of the space. Such geodesic trees exhibit intricate fractal behaviour; for instance, while almost every point in the space has only one geodesic going to the fixed point, there exists an atypical set of points which admit multiple such geodesics. In this paper, we consider the directed landscape, the recently constructed scaling limit of exponential last passage percolation (LPP), with the aim of developing tools to analyse the fractal aspects of the tree of semi-infinite geodesics in a given direction. We use the duality (Pimentel '16) between the geodesic tree and the interleaving competition interfaces in exponential LPP to obtain a duality between the geodesic tree and the corresponding dual tree in the landscape. Using this, we show that problems concerning the fractal behaviour of sets of atypical points for the geodesic tree can be transformed into corresponding problems for the dual tree, which might turn out to be easier. In particular, we use this method to show that the set of points having multiple semi-infinite geodesics in a fixed direction a.s. has Hausdorff dimension 4/34/3, thereby answering a question posed in Busani-Sepp\"{a}l\"{a}inen-Sorensen '22. We also show that the set of points admitting three semi-infinite geodesics in a fixed direction is a.s. countable.Comment: 26 pages, 5 figures; small corrections and the addition of an appendi

    Self-powered weigh-in-motion system combining vibration energy harvesting and self-sensing composite pavements

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    Overloaded vehicles are the primary cause of accelerated degradation of road infrastructures. In this context, although weigh-in-motion (WIM) systems are most efficient to enforce weight regulations, current technologies require costly investments limiting their extensive implementation. Recent advances in multifunctional composites enabled cost-efficient alternatives in the form of smart pavements. Nevertheless, the need for a stable power supply still represents a major practical limitation. This work presents a novel proof-of-concept self-sustainable WIM technology combining smart pavements and vibration-based energy harvesting (EH). The feasibility of piezoelectric bimorph cantilevered beams to harvest traffic-induced vibrations is firstly investigated, followed by the demonstration of the proposed technology under laboratory conditions. The main original contributions of this work comprise (i) the development of a new self-powered data acquisition system, (ii) a novel approach for the fabrication and electromechanical testing of the piezoresistive composite pavement, and (iii) laboratory feasibility analysis of the developed EH unit to conduct traffic load identification through electrical resistivity measurements of the smart pavement. While the presented results conclude the need for dense EH networks or combinations of different EH technologies to attain complete self-sustainability, this work represents an initial feasibility evidence paving the way towards the development of self-powered low-cost WIM systems

    Sputter deposition on composites : interplay between film and substrate properties

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    C.S. Lewis, Public Intellectual

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    Magma Chemical Evolution in the Lesser Antilles Arc Crust: Insights from Plutonic Xenoliths

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    Magmas generated beneath volcanic arcs at subduction zones must traverse the crust of the overriding plate, via “magma plumbing systems” prior to eruption. Magma plumbing systems are predominantly composed of crystal mush, where low volumes of melt are distributed throughout higher volumes of crystals. To understand processes controlling the chemical compositions of arc lavas, it is essential to constrain how magmas are chemically modified within mushy plumbing systems during storage and transit through the upper plate crust. Arc lavas often carry fragments of crystal mush, known as plutonic xenoliths, to the surface, which can be used to study the influence of crustal processes on arc magma chemical compositions. This thesis investigates plutonic xenoliths from the islands of Martinique and St Vincent in the active intra-oceanic Lesser Antilles arc. These samples are used to determine whether the majority of the trace element and isotopic variation in Lesser Antilles arc lavas can be produced by crustal processes. Strontium isotopic compositions of plagioclase, in plutonic xenoliths derived from different crustal depths, are used to demonstrate that isotopic variation and highly radiogenic isotopic compositions observed in Martinique lavas are acquired via assimilation of upper crustal sediments. Textural features and mineral trace element compositions in St Vincent plutonic xenoliths record polybaric fractional crystallization and melt-mush reaction processes. These two processes control magma chemical evolution in mushes beneath the island and consequently influence the trace element compositions of St Vincent lavas. These findings suggest that majority of trace element and radiogenic isotopic variation in Lesser Antilles arc lavas is generated within mushy magma plumbing systems in the arc crust. An important wider implication is that contributions from crustal processes must be well constrained before using trace element and isotopic compositions of arc lavas to assess subduction recycling processes and mantle source heterogeneity
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