805 resultados para Sandstone climbing


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Acknowledgements The Authors are indebted with Dr. Barbara Cerasetti, scientific coordinator of the Italian Archaeological Program in Turkmenistan (Dipartimento di Storia, Culture, Civiltà – Università di Bologna – Ministero per gli Affari Esteri – MAE), for the logistical help before and during the field activities in Turkmenistan. Our thanks to the administration of the National Institute of Deserts, Flora and Fauna, to the Turkmenistan Government and to Dr Aman Nigarov for the fruitful assistance in the field. We thank Prof. Marco Antonellini for the discussions on sandstone intrusions. The authors are indebted to the reviewers J. Peakall, P. Imbert, A. Hurst and an anonymous reviewer for the very helpful comments to the manuscript. Funding was provided by Prof. G. Gabbianelli for the field survey and by PRIN 2009 grants to Prof. Rossella Capozzi.

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Temperature and moisture conditions are key drivers of stone weathering processes in both natural and built environments. Given their importance in the breakdown of stone, a detailed understanding of their temporal and spatial variability is central to understanding present-day weathering behaviour and for predicting how climate change may influence the nature and rates of future stone decay.
Subsurface temperature and moisture data are reported from quarry fresh Peakmoor Sandstone samples exposed during summer (June–July) and late autumn / early winter (October–December) in a mid-latitude, temperate maritime environment. These data demonstrate that the subsurface thermal response of sandstone comprises numerous short-term (minutes), low magnitude fluctuations superimposed upon larger-scale diurnal heating and cooling cycles with distinct aspect-related differences. The short-term fluctuations create conditions in the outer 5–10 mm of stone that are much more ‘energetic’ in comparison to the more subdued thermal cycling that occurs deeper within the sandstone samples.
Data show that moisture dynamics are equally complex with a near-surface region (5–10 mm) in which frequent moisture cycling takes place and this, combined with the thermal dynamism exhibited by the same region may have significant implications for the nature and rate of weathering activity. Data indicate that moisture input from rainfall, particularly when it is wind-driven, can travel deep into the stone where it can prolong the time of wetness. This most often occurs during wetter winter months when moisture input is high and evaporative loss is low but can happen at any time during the year when the hydraulic connection between near-surface and deeper regions of the stone is disrupted with subsequent loss of moisture from depth slowing as it becomes reliant on vapour diffusion alone.
These data illustrate the complexity of temperature and moisture conditions in sandstone exposed to the ‘moderate’ conditions of a temperate maritime environment. They highlight differences in thermal and moisture cycling between near-surface (5–10 mm) and deeper regions within the stone and contribute towards a better understanding of the development of structural and mineralogical heterogeneity between the stone surface and substrate.

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Conventional taught learning practices often experience difficulties in keeping students motivated and engaged. Video games, however, are very successful at sustaining high levels of motivation and engagement through a set of tasks for hours without apparent loss of focus. In addition, gamers solve complex problems within a gaming environment without feeling fatigue or frustration, as they would typically do with a comparable learning task. Based on this notion, the academic community is keen on exploring methods that can deliver deep learner engagement and has shown increased interest in adopting gamification – the integration of gaming elements, mechanics, and frameworks into non-game situations and scenarios – as a means to increase student engagement and improve information retention. Its effectiveness when applied to education has been debatable though, as attempts have generally been restricted to one-dimensional approaches such as transposing a trivial reward system onto existing teaching materials and/or assessments. Nevertheless, a gamified, multi-dimensional, problem-based learning approach can yield improved results even when applied to a very complex and traditionally dry task like the teaching of computer programming, as shown in this paper. The presented quasi-experimental study used a combination of instructor feedback, real time sequence of scored quizzes, and live coding to deliver a fully interactive learning experience. More specifically, the “Kahoot!” Classroom Response System (CRS), the classroom version of the TV game show “Who Wants To Be A Millionaire?”, and Codecademy’s interactive platform formed the basis for a learning model which was applied to an entry-level Python programming course. Students were thus allowed to experience multiple interlocking methods similar to those commonly found in a top quality game experience. To assess gamification’s impact on learning, empirical data from the gamified group were compared to those from a control group who was taught through a traditional learning approach, similar to the one which had been used during previous cohorts. Despite this being a relatively small-scale study, the results and findings for a number of key metrics, including attendance, downloading of course material, and final grades, were encouraging and proved that the gamified approach was motivating and enriching for both students and instructors.

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International audience

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Trabalho apresentado no 41th IAHS World Congress, 13-16 de setembro de 2016, Albufeira, Portugal

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"This essay first appeared in the ninth volume of the 'Journal of the Linnean Society' 1865."--Pref.

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The state of Florida has one of the most severe exotic species invasion problems in the United States, but little is known about their influence on soil biogeochemistry. My dissertation research includes a cross-continental field study in Australia, Florida, and greenhouse and growth chamber experiments, focused on the soil-plant interactions of one of the most problematic weeds introduced in south Florida, Lygodium microphyllum (Old World climbing fern). Analysis of field samples from the ferns introduced and their native range indicate that L microphyllum is highly dependent on arbuscular mycorrhizal fungi (AMF) for phosphorus uptake and biomass accumulation. Relationship with AMF is stronger in relatively dry conditions, which are commonly found in some Florida sites, compared to more common wet sites where the fern is found in its native Australia. In the field, L. microphyllum is found to thrive in a wide range of soil pH, texture, and nutrient conditions, with strongly acidic soils in Australia and slightly acidic soils in Florida. Soils with pH 5.5 - 6.5 provide the most optimal growth conditions for L. microphyllum, and the growth declines significantly at soil pH 8.0, indicating that further reduction could happen in more alkaline soils. Comparison of invaded and uninvaded soil characteristics demonstrates that L. microphyllum can change the belowground soil environment, with more conspicuous impact on nutrient-poor sandy soils, to its own benefit by enhancing the soil nutrient status. Additionally, the nitrogen concentration in the leaves, which has a significant influence in the relative growth rate and photosynthesis, was significantly higher in Florida plants compared to Australian plants. Given that L. microphyllum allocates up to 40% of the total biomass to rhizomes, which aid in rapid regeneration after burning, cutting or chemical spray, hence management techniques targeting the rhizomes look promising. Over all, my results reveal for the first time that soil pH, texture, and AMF are major factors facilitating the invasive success of L. mcirophyllum. Finally, herbicide treatments targeting rhizomes will most likely become the widely used technique to control invasiveness of L. microphyllum in the future. However, a complete understanding of the soil ecosystem is necessary before adding any chemicals to the soil to achieve a successful long-term invasive species management strategy.

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Laser ablation ICP-MS U–Pb analyses have been conducted on detrital zircon of Upper Triassic sandstone from the Alentejo and Algarve basins in southwest Iberia. The predominance of Neoproterozoic, Devonian, Paleoproterozoic and Carboniferous detrital zircon ages confirms previous studies that indicate the locus of the sediment source of the late Triassic Alentejo Basin in the pre-Mesozoic basement of the South Portuguese and Ossa-Morena zones. Suitable sources for the Upper Triassic Algarve sandstone are the Upper Devonian–Lower Carboniferous of the South Portuguese Zone (Phyllite–Quartzite and Tercenas formations) and the Meguma Terrane (present-day in Nova Scotia). Spatial variations of the sediment sources of both Upper Triassic basins suggest a more complex history of drainage than previously documented involving other source rocks located outside present-day Iberia. The two Triassic basins were isolated from each other with the detrital transport being controlled by two independent drainage systems. This study is important for the reconstruction of the late Triassic paleogeography in a place where, later, the opening of the Central Atlantic Ocean took place separating Europe from North America.

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In sport climbing, athletes with vision impairments are constantly accompanied by their guides – usually trainers – both during the preparatory inspection of the routes and whilst climbing. Trainers are, so to speak, the climbers’ eyes, in the sense that they systematically put their vision in the service of the climbers’ mobility and sporting performance. The synergy between trainers and athletes is based on peculiar, strictly multimodal interactive practices that are focused on the body and on its constantly evolving sensory engagement with the materiality of routes. In this context, sensory perception and embodied actions required to plan and execute the climb are configured as genuinely interactive accomplishments. Drawing on the theoretical framework of Embodied and Situated Cognition and on the methodology of Conversation Analysis, this thesis engages in the multimodal analysis of trainer-athlete interactions in paraclimbing. The analysis is based on a corpus of video recorded climbing sessions. The major findings of the study can be summarized as follows. 1) Intercorporeality is key to interactions between trainers and athletes with visual impairments. The participants orient to perceiving the climbing space and acting in it as a ‘We’. 2) The grammar, lexicon, prosody, and timing of the trainers’ instructions are finely tuned to the ongoing corporeal experience of the climbers. 3) Climbers with visual impairments build their actions by using sensory resources that are provided by their trainers. This result is of particular importance as it shows that resources and constraints for action are in a fundamental way constituted in interaction with Others and with specific socio-material ecologies, rather than being defined a priori by the organs and functions of individuals’ body and mind. Individual capabilities are thus enhanced and extended in interaction, which encourages a more ecological view of (dis)ability.

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A case of a tinea favosa involving the scalp of a child represented in the painting Boys climbing a tree (Muchachos trepando a un árbol), by Francisco Goya y Lucientes, with pictorial representation of favic scutula and consequent alopecia.