4,815 research outputs found

    Significant Population Structure and Little Connectivity in South African Rocky Shore Species: Implications for the Conservation of Regional Marine Biodiversity

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    South Africa has 3650 km of coastline that spans the boundary between the Atlantic and Indo-Pacific biomes. The coastal waters boast a remarkable array of biological diversity and high levels of species abundance and endemism. Currently around 23% of the coastline is formally protected via marine protected areas (MPA) with 9% enforced as no-take zones. Even with this relatively high level of protection (as compared to other nations globally) the MPA network is still relatively sparse with protected areas that are on average ~110 km apart and unevenly distributed with the majority of MPAs situated along the species-rich east coast. This has led to concerns that the current MPA network is not protecting a representative sample of the genetic diversity among marine species nor is it sufficiently genetically connected via dispersal and gene flow to ensure their long-term persistence. To test a number of questions regarding the distribution of genetic diversity and degree of population genetic structuring along the South African coast we analyzed mitochondrial DNA sequence data for 10 sessile rocky-shore species and one reef-fish that represent three distinct life history strategies. We find that the distribution of genetic diversity across the South African coastline closely mirrors the distribution of species richness, increasing from west to east. We also find similar levels of population genetic structure among brooders, broadcast spawners and live-bearers, demonstrating that life histories are a poor predictor of genetic connectivity for South African marine species. Finally, we find that estimates of effective dispersal distance for taxa from each of the life history categories are low (~0.5-1.5 km per generation) suggesting that populations within MPAs are reliant on populations in unprotected areas via a steppingstone model of genetic connectivity. In light of these findings, we discuss a number of recommendations to enhance the role of the existing South African MPA network and echo previous calls for the establishment of protected areas along the west coast

    Hydraulic Model Study: Wyandotte Wastewater Treatment Plant Influent Pump Station Wet Well

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    https://deepblue.lib.umich.edu/bitstream/2027.42/154185/1/39015101405044.pd

    Research Methods for Education With Technology: Four Concerns, Examples, and Recommendations

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    The success of education with technology research is in part because the field draws upon theories and methods from multiple disciplines. However, drawing upon multiple disciplines has drawbacks because sometimes the methodological expertise of each discipline is not applied when researchers conduct studies outside of their research training. The focus here is on research using methods drawn largely from psychology, for example, evaluating the impact of different systems on how students perform. The methodological concerns discussed are: low power; not using multilevel modeling; dichotomization; and inaccurate reporting of the numeric statistics. Examples are drawn from a recent set of proceedings. Recommendations, which are applicable throughout the social sciences, are made for each of these

    Improved SAR Imaging Via Cross-Learning from Camera Images

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    In this paper, we propose a novel concept of cross-learning, in order to improve SAR images by learning from the camera images. We use a multi-level abstraction approach to materialise knowledge transfer between the two modalities. We also compare the performance of other possible approaches. We provide experimental results on real data to validate the proposed concept

    A Remote Sensing-Based Tool for Assessing Rainfall-Driven Hazards

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    RainyDay is a Python-based platform that couples rainfall remote sensing data with Stochastic Storm Transposition (SST) for modeling rainfall-driven hazards such as floods and landslides. SST effectively lengthens the extreme rainfall record through temporal resampling and spatial transposition of observed storms from the surrounding region to create many extreme rainfall scenarios. Intensity-Duration-Frequency (IDF) curves are often used for hazard modeling but require long records to describe the distribution of rainfall depth and duration and do not provide information regarding rainfall space-time structure, limiting their usefulness to small scales. In contrast, Rainy Day can be used for many hazard applications with 1-2 decades of data, and output rainfall scenarios incorporate detailed space-time structure from remote sensing. Thanks to global satellite coverage, Rainy Day can be used in inaccessible areas and developing countries lacking ground measurements, though results are impacted by remote sensing errors. Rainy Day can be useful for hazard modeling under nonstationary conditions

    Imaging Moving Targets for a Forward Scanning Automotive SAR

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    The choice of response alternatives in COVID-19 social science surveys

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    Social science research is key for understanding and for predicting compliance with COVID-19 guidelines, and this research relies on survey data. While much focus is on the survey question stems, less is on the response alternatives presented that both constrain responses and convey information about the assumed expectations of the survey designers. The focus here is on the choice of response alternatives for the types of behavioral frequency questions used in many COVID-19 and other health surveys. We examine issues with two types of response alternatives. The first are vague quantifiers, like “rarely” and “frequently.” Using data from 30 countries from the Imperial COVID data hub, we show that the interpretation of these vague quantifiers (and their translations) depends on the norms in that country. If the mean amount of hand washing in a country is high, it is likely “frequently” corresponds to a higher numeric value for hand washing than if the mean in the country is low. The second type are sets of numeric alternatives and they can also be problematic. Using a US survey, respondents were randomly allocated to receive either response alternatives where most of the scale corresponds to low frequencies or where most of the scale corresponds to high frequencies. Those given the low frequency set provided lower estimates of the health behaviors. The choice of response alternatives for behavioral frequency questions can affect the estimates of health behaviors. How the response alternatives mold the responses should be taken into account for epidemiological modeling. We conclude with some recommendations for response alternatives for behavioral frequency questions in surveys
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