[1] Periods of high astronomically generated tides contribute to the occurrence of extreme sea levels. Over interannual time scales, two precessions associated with the orbit of the Moon cause systematic variation of high tides. A global assessment of when these tidal modulations occur allows for the prediction of periods when the enhanced risk of coastal flooding is likely in different parts of the world. This paper uses modeled tides to assess the influence of the 18.61 year lunar nodal cycle and the 8.85 year cycle of lunar perigee (which affects high tidal levels as a quasi 4.4 year cycle) on high tidal levels on a global scale. Tidal constituents from the TPXO7.2 global tidal model are used, with satellite modulation corrections based on equilibrium tide expectations, to predict multidecadal hourly time series of tides on a one-quarter degree global grid. These time series are used to determine the amplitude and phase of tidal modulations using harmonic analysis fitted to 18.61, 9.305, 8.85, and 4.425 year sinusoidal signals. The spatial variations in the range and phase of the tidal modulations are related to the global distribution of the main tidal constituents and tidal characteristics (diurnal or semidiurnal and tidal range). Results indicate that the 18.61 year nodal cycle has the greatest influence in diurnal regions with tidal ranges of >4 m and that the 4.4 year cycle is largest in semidiurnal regions where the tidal range is >6 m. The phase of the interannual tidal modulations is shown to relate to the form of the tide.
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BACKGROUNDWhile previously researching the educational impacts of single-course and cross-curricular portfolios, investigators noted that student participants described their portfolio activities as positively impacting their growing identities as engineering professionals. These impacts were seen particularly in studies regarding cross-curricular portfolios.
PURPOSE (HYPOTHESIS)This study was designed to explicitly investigate identity-related impacts of cross-curricular portfolios and to explore the processes students employed during portfolio construction to identify themselves as budding engineers and as future professionals.
DESIGN/METHODEngineering undergraduate students attended four weekly workshops where they wrote a professional statement, selected artifacts that demonstrated their engineering abilities, and wrote annotations that explained how the artifacts served as concrete examples of their claims for professional standing. Online surveys were administered at each workshop asking participants about their ongoing experiences of creating their portfolios and sharing these portfolios with their peers.
RESULTSAnalysis of the survey responses revealed that participants had two primary frames of reference for the construction of professional identity during portfolio creation. The external frame of reference focused on students' understanding of the expectations of potential employers and recruiters. The internal frame of reference, which accounted for twice as many responses as the external frame coding, focused on students' emerging realizations of their own values and interests as professional engineers.
CONCLUSIONSAs engineering educators, we often support the external frame of reference in terms of building professional identity. We need to provide students with opportunities to engage the internal frame of reference with which our participants were particularly concerned.
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