500 research outputs found

    Stable Isotope Analysis of Japan Sea and East China Sea Sediments: Late Pleistocene Paleoceanographic Reconstructions

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    The East Asian Monsoon system is an important dynamic of East Asian climates, affecting over one-third of the world’s population. Marginal seas within East Asia are ideal environments to study past fluctuations of monsoon intensities and durations as they are sensitive to climatic and glacio-eustatic sea level changes. This study focuses on continuous sedimentary sequences collected from three Integrated Oceanic Drilling Program Expedition 346 sites; Sites U1426 and U1427 in the Japan Sea and Site U1429 in the East China Sea. Elemental concentration (%TOC, %TN, and %CaCO3) and stable isotope ratios (δ13C and δ15N) are viable proxies to reconstruct past relative productivity rates. Japan Sea sediments show clear differentiation between glacial and interglacial periods in the proxies studied with increased elemental concentrations and isotopic enrichment indicative of increased relative paleoproductivity rates occurring in interglacial periods with sea levels \u3e70 m. Glacial periods, in comparison, generally have decreased relative paleoproductivity rates with decreased elemental concentrations and isotopic depletion. Nitrogen isotopes (δ15N) do not follow the same enrichment cycles as the other geochemical proxies and generally show the most enriched values during glacial low stands, likely indicating anoxic bottom water conditions and denitrification through bacterial processes. The Mid-Pleistocene Transition (MPT) was also identified in Site U1426 sediments through the use of continuous wavelet analysis and multitaper method spectral analysis. Before the MPT, the higher frequency orbital periods of precession and obliquity dominated the paleoproductivity cyclicities while a lower frequency 100,000-year cycle developed at the MPT and dominated the cyclicity to the present. East China Sea sediments do not show clear differentiation between glacial and interglacial periods and instead have relatively constant elemental and isotopic values during the last 350,000 years with the exception of negative excursions during stadial events during Marine Isotope Stage (MIS) 5 and MIS 7. The abrupt negative excursions likely resulted from decreased flow of the Kuroshio Current and reduced upwelling of the Kuroshio Intermediate Water throughout the Okinawa Trough during periods of decreased sea levels. Reduced flow of the Kuroshio Current likely led to the deposition of gravity flow layers during these stadial events

    What can we get “help” to observe when it comes to mobile use and mobile user experience?

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    Mobile devices and mobile services have been around long enough for the research community to start thinking about the next step in studying them: larger user groups and longer periods of time. Strictly quantitative methods are not very useful when it comes to studying user experience so we need to find scalable ways to support our qualitative methods to be able to take this next step. This paper reflects on automatic gathering of context data as one such way

    Multitasking effects on individual performance : an experimental eye-tracking study

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    Purpose: The main objective of this research is to identify the impact of parallel performance of various tasks on the individual effectiveness. Moreover, a methodological goal was set for the research to explore the possibilities of using eye-tracking in the studies of multitasking. Design/Methodology/Approach: The study was conducted in the form of an experiment. All participants worked at the same computer station time was measured with Eye Tracker. Findings: It was confirmed that multitasking requires more time to accomplish tasks and deteriorates creativity, but not correctness of the answers in case of simple tasks. Interestingly, in case of multitasking under time pressure, the performance was worse. Practical Implications: Deeper understanding of the determinants and effects of multitasking on organizational and individual performance enables the adjustment of work organization and management style in order to achieve optimal results. Originality/Value: This paper brings new insights to the studies of multitasking not only in terms of the results of an experimental research, but also in terms of methodological concerns like eye-tracking as a new method of empirical diagnosis.peer-reviewe

    Data Work in a Knowledge-Broker Organization: How Cross-Organizational Data Maintenance shapes Human Data Interactions.

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    Implementing an Agent Trade Server

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    An experimental server for stock trading autonomous agents is presented and made available, together with an agent shell for swift development. The server, written in Java, was implemented as proof-of-concept for an agent trade server for a real financial exchange.Comment: 14 pages, 7 figures, intended for B/W printin

    Human-computer interaction for development (HCI4D):the Southern African landscape

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    Human-Computer interaction for development (HCI4D) research aims to maximise the usability of interfaces for interacting with technologies designed specifically for under-served, under-resourced, and under-represented populations. In this paper we provide a snapshot of the Southern African HCI4D research against the background of the global HCI4D research landscape.We commenced with a systematic literature review of HCI4D (2010-2017) then surveyed Southern African researchers working in the area. The contribution is to highlight the context- specific themes and challenges that emerged from our investigation
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