70 research outputs found

    Storm impact on sea surface temperature and chlorophyll α in the Gulf of Mexico and Sargasso Sea based on daily cloud-free satellite data reconstructions

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    Author Posting. © American Geophysical Union, 2016. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 43 (2016): 12,199–12,207, doi:10.1002/2016GL071178.Upper ocean responses to tropical storms/hurricanes have been extensively studied using satellite observations. However, resolving concurrent sea surface temperature (SST) and chlorophyll α (chl α) responses along storm tracks remains a major challenge due to extensive cloud coverage in satellite images. Here we produce daily cloud-free SST and chl α reconstructions based on the Data INterpolating Empirical Orthogonal Function method over a 10 year period (2003–2012) for the Gulf of Mexico and Sargasso Sea regions. Daily reconstructions allow us to characterize and contrast previously obscured subweekly SST and chl α responses to storms in the two main storm-impacted regions of the Atlantic Ocean. Statistical analyses of daily SST and chl α responses revealed regional differences in the response time as well as the response sensitivity to maximum sustained wind speed and translation speed. This study demonstrates that SST and chl α responses clearly depend on regional ocean conditions and are not as universal as might have been previously suggested.Gulf of Mexico Research Initiative/GISR Grant Number: 02-S130202; NOAA Grant Number: NA11NOS0120033; NASA Grant Numbers: NNX12AP84G, NNX13AD80G2017-06-1

    Evaluation of agronomic traits in Chinese wild grapes and screening superior accessions for use in a breeding program

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    This study was conducted to evaluate 15 agronomic traits in 67 accessions of 13 Chinese wild Vitis species. The results have been used to screen superior accessions for grape breeding in the future. Chinese wild Vitis had high diversity in economic traits among the species, such as bud-burst date, blooming date, berry ripening date, bunch weights, berry weights, berry soluble solid contents, berry acid contents, and vine production. Bunch weights of 56 Chinese wild accessions and berry weights of 12 Chinese species (except V. davidii) were much smaller than those of the two European cultivars. In our 25-year of evaluation on disease resistance and economic qualities in this Chinese germplasm, we suggest that V. quinquangularis, V. amurensis, V. yeshanensis, V. romanetii, and certain accessions in V. liubanensis be the first potential materials chosen for breeding.

    Comparison of resistance to powdery mildew and downy mildew in Chinese wild grapes

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    This research was performed under natural conditions in an effort to compare resistance within Chinese Vitis germplasm to powdery mildew and downy mildew. Sixty-six genotypes of 13 Chinese wild Vitis species were selected to evaluate disease resistance. Seven among these 13 species, V. amurensis, V. romanetii, V. piazezkii, V. davidii, V. davidii var. cyanocarpa, V. liubanensis, and V. bashanica showed resistance to powdery mildew. Three species, V. yeshanensis, V. davidii var. cyanocarpa, and V. pseudoreticulata exhibited resistance to downy mildew. Among 66 genotypes, 46 were resistant to powdery mildew, 28 were resistant to downy mildew and 19 genotypes had resistance to both diseases. Although more than half of the genotypes exhibited resistance to powdery mildew and a lesser number expressed resistance to downy mildew, resistance to both diseases in Chinese Vitis were significantly related (r = 0.395, df = 64, r0,01 = 0.325). Also, there is resistance variation regarding both diseases between the species and also, to a lesser degree, among the genotypes. The variation is not related to the geographic distribution of the germplasm. These variations should be considered when researchers collect the gemplasm on location, making every effort to obtain extensive genotypes for the breeding program.

    Relatedness of resistance to anthracnose and to white rot in Chinese wild grapes

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    Resistance to anthracnose and to white rot in 56 accessions of 13 Chinese wild Vitis species, V. amurensis, V. quinquangularis, V. romanetii, V. adstricta, V. pseudoreticulata, V. piazezkii, V. davidii, V. davidii var. cyanocarpa, V. liubanensis, V. qinlingensis, V. bashanica, V. yeshanensis and V. hankockii was evaluated under natural conditions in 1996-1998. All 56 accessions and the 13 species showed resistance to anthracnose. All nine accessions of V. quinquangularis, and one accession each of V. romanetii, V. adstricta and V. pseudoreticulata exhibited susceptibility to white rot; the remaining 44 accessions (78.57 %) and the other 9 species presented resistant to grape white rot. Two V. vinifera cultivars (‘Cabernet Sauvignon’ and ‘Chardonnay’) were susceptible to anthracnose and highly susceptible to white rot. The r-value of susceptibility indices between anthracnose and white rot in the 56 accessions is insignificant. In Chinese wild grapes, the mechanisms for producing resistance to both diseases would be very different, but inheritance of resistance to these two diseases in a certain cross is somewhat related by molecular data.

    Variational data assimilative modeling of the Gulf of Maine in spring and summer 2010

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    Author Posting. © American Geophysical Union, 2015. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 120 (2015): 3522–3541, doi:10.1002/2014JC010492.A data assimilative ocean circulation model is used to hindcast the Gulf of Maine [GOM) circulation in spring and summer 2010. Using the recently developed incremental strong constraint 4D Variational data assimilation algorithm, the model assimilates satellite sea surface temperature and in situ temperature and salinity profiles measured by expendable bathythermograph, Argo floats, and shipboard CTD casts. Validation against independent observations shows that the model skill is significantly improved after data assimilation. The data-assimilative model hindcast reproduces the temporal and spatial evolution of the ocean state, showing that a sea level depression southwest of the Scotian Shelf played a critical role in shaping the gulf-wide circulation. Heat budget analysis further demonstrates that both advection and surface heat flux contribute to temperature variability. The estimated time scale for coastal water to travel from the Scotian Shelf to the Jordan Basin is around 60 days, which is consistent with previous estimates based on in situ observations. Our study highlights the importance of resolving upstream and offshore forcing conditions in predicting the coastal circulation in the GOM.Research support was provided by National Oceanic and Atmospheric Administration (NOAA) grant NA06NOS4780245 for the Gulf of Maine Toxicity (GOMTOX) program. RH and DJM were also supported by NOAA grant NA11NOS4780023 under the PCMHAB program. YL was partly supported by Postdoctoral Scholar Program at the Woods Hole Oceanographic Institution, with funding provided by the George D. Grice Postdoctoral Scholarship.2015-11-1

    Dynamics of an intense Alexandrium catenella red tide in the Gulf of Maine: satellite observations and numerical modeling

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    © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Li, Y., Stumpf, R. P., McGillicuddy, D. J.,Jr, & He, R. Dynamics of an intense Alexandrium catenella red tide in the Gulf of Maine: satellite observations and numerical modeling. Harmful Algae, 99, (2020): 101927, doi:10.1016/j.hal.2020.101927.In July 2009, an unusually intense bloom of the toxic dinoflagellate Alexandrium catenella occurred in the Gulf of Maine. The bloom reached high concentrations (from hundreds of thousands to one million cells L−1) that discolored the water and exceeded normal bloom concentrations by a factor of 1000. Using Medium Resolution Imaging Spectrometer (MERIS) imagery processed to target chlorophyll concentrations (>2 µg L−1), patches of intense A. catenella concentration were identified that were consistent with the highly localized cell concentrations observed from ship surveys. The bloom patches were generally aligned with the edge of coastal waters with high-absorption. Dense bloom patches moved onshore in response to a downwelling event, persisted for approximately one week, then dispersed rapidly over a few days and did not reappear. Coupled physical-biological model simulations showed that wind forcing was an important factor in transporting cells onshore. Upward swimming behavior facilitated the horizontal cell aggregation, increasing the simulated maximum depth-integrated cell concentration by up to a factor of 40. Vertical convergence of cells, due to active swimming of A. catenella from the subsurface to the top layer, could explain the additional 25-fold intensification (25 × 40=1000-fold) needed to reach the bloom concentrations that discolored the water. A model simulation that considered upward swimming overestimated cell concentrations downstream of the intense aggregation. This discrepancy between model and observed concentrations suggested a loss of cells from the water column at a time that corresponded to the start of encystment. These results indicated that the joint effect of upward swimming, horizontal convergence, and wind-driven flow contributed to the red water event, which might have promoted the sexual reproduction event that preceded the encystment process.DJM gratefully acknowledges support of the Woods Hole Center for Oceans and Human Health, funded jointly by the National Science Foundation (OCE-1314642 and OCE-1840381) the National Institute of Environmental Health Sciences (P01ES021923–01 and P01 ES028938–01). RH acknowledges support made possible by NOAA grant NA15NOS4780196 and NA16NOS0120028

    Finding the Missing-half: Graph Complementary Learning for Homophily-prone and Heterophily-prone Graphs

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    Real-world graphs generally have only one kind of tendency in their connections. These connections are either homophily-prone or heterophily-prone. While graphs with homophily-prone edges tend to connect nodes with the same class (i.e., intra-class nodes), heterophily-prone edges tend to build relationships between nodes with different classes (i.e., inter-class nodes). Existing GNNs only take the original graph during training. The problem with this approach is that it forgets to take into consideration the ``missing-half" structural information, that is, heterophily-prone topology for homophily-prone graphs and homophily-prone topology for heterophily-prone graphs. In our paper, we introduce Graph cOmplementAry Learning, namely GOAL, which consists of two components: graph complementation and complemented graph convolution. The first component finds the missing-half structural information for a given graph to complement it. The complemented graph has two sets of graphs including both homophily- and heterophily-prone topology. In the latter component, to handle complemented graphs, we design a new graph convolution from the perspective of optimisation. The experiment results show that GOAL consistently outperforms all baselines in eight real-world datasets.Comment: Accepted by ICML 202

    A Survey on Fairness-aware Recommender Systems

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    As information filtering services, recommender systems have extremely enriched our daily life by providing personalized suggestions and facilitating people in decision-making, which makes them vital and indispensable to human society in the information era. However, as people become more dependent on them, recent studies show that recommender systems potentially own unintentional impacts on society and individuals because of their unfairness (e.g., gender discrimination in job recommendations). To develop trustworthy services, it is crucial to devise fairness-aware recommender systems that can mitigate these bias issues. In this survey, we summarise existing methodologies and practices of fairness in recommender systems. Firstly, we present concepts of fairness in different recommendation scenarios, comprehensively categorize current advances, and introduce typical methods to promote fairness in different stages of recommender systems. Next, after introducing datasets and evaluation metrics applied to assess the fairness of recommender systems, we will delve into the significant influence that fairness-aware recommender systems exert on real-world industrial applications. Subsequently, we highlight the connection between fairness and other principles of trustworthy recommender systems, aiming to consider trustworthiness principles holistically while advocating for fairness. Finally, we summarize this review, spotlighting promising opportunities in comprehending concepts, frameworks, the balance between accuracy and fairness, and the ties with trustworthiness, with the ultimate goal of fostering the development of fairness-aware recommender systems.Comment: 27 pages, 9 figure
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