407 research outputs found

    Dynamic Power Spectral Analysis of Solar Measurements from Photospheric, Chromospheric, and Coronal Sources

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    An important aspect in the power spectral analysis of solar variability is the quasistationary and quasiperiodic nature of solar periodicities. In other words, the frequency, phase, and amplitude of solar periodicities vary on time scales ranging from active region lifetimes to solar cycle time scales. Here, researchers employ a dynamic, or running, power spectral density analysis to determine many periodicities and their time-varying nature in the projected area of active sunspot groups (S sub act). The Solar Maximum Mission/Active Cavity Radiometer Irradiance Monitor (SMM/ACRIM) total solar irradiance (S), the Nimbus-7 MgII center-to-wing ratio (R (MgII sub c/w)), the Ottawa 10.7 cm flux (F sub 10.7), and the GOES background x ray flux (X sub b) for the maximum, descending, and minimum portions of solar cycle 21 (i.e., 1980 to 1986) are used. The technique dramatically illustrates several previously unrecognized periodicities. For example, a relatively stable period at about 51 days has been found in those indices which are related to emerging magnetic fields. The majority of solar periodicities, particularly around 27, 150 and 300 days, are quasiperiodic because they vary in amplitude and frequency throughout the solar cycle. Finally, it is shown that there are clear differences between the power spectral densities of solar measurements from photospheric, chromospheric, and coronal sources

    Whole body interaction in abstract domains

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    Whole Body Interaction appears to be a good fit of interaction style for some categories of application domain, such as the motion capture of gestures for computer games and virtual physical sports. However, the suitability of whole body interaction for more abstract application domains is less apparent, and the creation of appropriate whole body interaction designs for complex abstract areas such as mathematics, programming and musical harmony remains challenging. We argue, illustrated by a detailed case study, that conceptual metaphor theory and sensory motor contingency theory offer analytic and synthetic tools whereby whole body interaction can in principle be applied usefully to arbitrary abstract application domains. We present the case study of a whole body interaction system for a highly abstract application area, tonal harmony in music. We demonstrate ways in which whole body interaction offers strong affordances for action and insight in this domain when appropriate conceptual metaphors are harnessed in the design. We outline how this approach can be applied to abstract domains in general, and discuss its limitations

    Managed Aquifer Recharge as a Tool to Enhance Sustainable Groundwater Management in California

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    A growing population and an increased demand for water resources have resulted in a global trend of groundwater depletion. Arid and semi-arid climates are particularly susceptible, often relying on groundwater to support large population centers or irrigated agriculture in the absence of sufficient surface water resources. In an effort to increase the security of groundwater resources, managed aquifer recharge (MAR) programs have been developed and implemented globally. MAR is the approach of intentionally harvesting and infiltrating water to recharge depleted aquifer storage. California is a prime example of this growing problem, with three cities that have over a million residents and an agricultural industry that was valued at 47 billion dollars in 2015. The present-day groundwater overdraft of over 100 km3 (since 1962) indicates a clear disparity between surface water supply and water demand within the state. In the face of groundwater overdraft and the anticipated effects of climate change, many new MAR projects are being constructed or investigated throughout California, adding to those that have existed for decades. Some common MAR types utilized in California include injection wells, infiltration basins (also known as spreading basins, percolation basins, or recharge basins), and low-impact development. An emerging MAR type that is actively being investigated is the winter flooding of agricultural fields using existing irrigation infrastructure and excess surface water resources, known as agricultural MAR. California therefore provides an excellent case study to look at the historical use and performance of MAR, ongoing and emerging challenges, novel MAR applications, and the potential for expansion of MAR. Effective MAR projects are an essential tool for increasing groundwater security, both in California and on a global scale. This chapter aims to provide an overview of the most common MAR types and applications within the State of California and neighboring semi-arid regions

    Neo-Atlantis: The Netherlands under a 5-m sea level rise

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    What could happen to the Netherlands if, in 2030, the sea level starts to rise and eventually, after 100 years, a sea level of 5 m above current level would be reached? This question is addressed by studying literature, by interviewing experts in widely differing fields, and by holding an expert workshop on this question. Although most experts believe that geomorphology and current engineering skills would enable the country to largely maintain its territorial integrity, there are reasons to assume that this is not likely to happen. Social processes that precede important political decisions - such as the growth of the belief in the reality of sea level rise and the framing of such decisions in a proper political context (policy window) - evolve slowly. A flood disaster would speed up the decision-making process. The shared opinion of the experts surveyed is that eventually part of the Netherlands would be abandoned. © 2008 The Author(s)

    Loss and damage and limits to adaptation: recent IPCC insights and implications for climate science and policy

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    Recent evidence shows that climate change is leading to irreversible and existential impacts on vulnerable communities and countries across the globe. Among other effects, this has given rise to public debate and engagement around notions of climate crisis and emergency. The Loss and Damage (L&D) policy debate has emphasized these aspects over the last three decades. Yet, despite institutionalization through an article on L&D by the United Nations Framework Convention on Climate Change (UNFCCC) in the Paris Agreement, the debate has remained vague, particularly with reference to its remit and relationship to adaptation policy and practice. Research has recently made important strides forward in terms of developing a science perspective on L&D. This article reviews insights derived from recent publications by the Intergovernmental Panel on Climate Change (IPCC) and others, and presents the implications for science and policy. Emerging evidence on hard and soft adaptation limits in certain systems, sectors and regions holds the potential to further build momentum for climate policy to live up to the Paris ambition of stringent emission reductions and to increase efforts to support the most vulnerable. L&D policy may want to consider actions to extend soft adaptation limits and spur transformational, that is, non-standard risk management and adaptation, so that limits are not breached. Financial, technical, and legal support would be appropriate for instances where hard limits are transgressed. Research is well positioned to further develop robust evidence on critical and relevant risks at scale in the most vulnerable countries and communities, as well as options to reduce barriers and limits to adaptation

    Adaptation to flood risk: Results of international paired flood event studies

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    As flood impacts are increasing in large parts of the world, understanding the primary drivers of changes in risk is essential for effective adaptation. To gain more knowledge on the basis of empirical case studies, we analyze eight paired floods, that is, consecutive flood events that occurred in the same region, with the second flood causing significantly lower damage. These success stories of risk reduction were selected across different socioeconomic and hydro-climatic contexts. The potential of societies to adapt is uncovered by describing triggered societal changes, as well as formal measures and spontaneous processes that reduced flood risk. This novel approach has the potential to build the basis for an international data collection and analysis effort to better understand and attribute changes in risk due to hydrological extremes in the framework of the IAHSs Panta Rhei initiative. Across all case studies, we find that lower damage caused by the second event was mainly due to significant reductions in vulnerability, for example, via raised risk awareness, preparedness, and improvements of organizational emergency management. Thus, vulnerability reduction plays an essential role for successful adaptation. Our work shows that there is a high potential to adapt, but there remains the challenge to stimulate measures that reduce vulnerability and risk in periods in which extreme events do not occur

    Groundwater depletion embedded in international food trade

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    Recent hydrological modelling1 and Earth observations2,3 have located and quantified alarming rates of groundwater depletion worldwide. This depletion is primarily due to water withdrawals for irrigation1,2,4, but its connection with the main driver of irrigation, global food consumption, has not yet been explored. Here we show that approximately eleven per cent of non-renewable groundwater use for irrigation is embedded in international food trade, of which two-thirds are exported by Pakistan, the USA and India alone. Our quantification of groundwater depletion embedded in the world’s food trade is based on a combination of global, cropspecific estimates of non-renewable groundwater abstraction and international food trade data. A vast majority of the world’s population lives in countries sourcing nearly all their staple crop imports from partners who deplete groundwater to produce these crops, highlighting risks for global food and water security. Some countries, such as the USA, Mexico, Iran and China, are particularly exposed to these risks because they both produce and import food irrigated from rapidly depleting aquifers. Our results could help to improve the sustainability of global food production and groundwater resource management by identifying priority regions and agricultural products at risk as well as the end consumers of these products

    Exploring the short-term and maintained effects of strategic instruction on the writing of 4th grade students: should strategies be focused on the process?

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    p.1769-1790The principal aim of strategy-focused instruction is to teach students strategies to control their writing processes and achieve quality writing. For this purpose, nine 4th grade Elementary School classes from three diferent schools (N=215) were randomly allocated to two forms of strategy-focused program called cognitive selfregulation instruction (CSRI). The full-CSRI (experimental condition 1, n=72) taught students a strategic approach to set appropriate product goals along with planning strategies. However, in the brief-CSRI (experimental condition 2, n=69), the direct teaching of planning procedures was removed. These two experimental conditions were compared with a control condition (n=74). We used a pre-test/posttest design and we also collected a maintenance writing performance 7 months after the intervention. Writing performance was holistically evaluated through readerbased measures made up of aspects related to structure, coherence, and quality. Only the full-CSRI condition wrote better compare–contrast texts than the control group in both the short term and at the maintenance timepoint. The study discusses the efects of the intervention on each measure and whether or not it is necessary to train process strategiesS
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