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Articles 1171 - 1200 of 5954

Full-Text Articles in Physical Sciences and Mathematics

Impacts Of Multiple Environmental Changes On Long‐Term Nitrogen Loading From The Chesapeake Bay Watershed, Shufen Pan, Zihao Bian, Hanqin Tian, Yuanzhi Yao, Raymond G. Najjar, Marjorie A.M. Friedrichs, Eileen E. Hofmann, Rongting Xu, Bowen Zhang Jan 2021

Impacts Of Multiple Environmental Changes On Long‐Term Nitrogen Loading From The Chesapeake Bay Watershed, Shufen Pan, Zihao Bian, Hanqin Tian, Yuanzhi Yao, Raymond G. Najjar, Marjorie A.M. Friedrichs, Eileen E. Hofmann, Rongting Xu, Bowen Zhang

CCPO Publications

Excessive nutrient inputs from land, particularly nitrogen (N), have been found to increase the occurrence of hypoxia and harmful algal blooms in coastal ecosystems. To identify the main contributors of increased N loading and evaluate the efficacy of water pollution control policies, it is essential to quantify and attribute the long‐term changes in riverine N export. Here, we use a state‐of‐the‐art terrestrial–aquatic interface model to examine how multiple environmental factors may have affected N export from the Chesapeake Bay watershed since 1900. These factors include changes in climate, carbon dioxide, land use, and N inputs (i.e., atmospheric N deposition, animal …

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Measuring Winds From Space To Reduce The Uncertainty In The Southern Ocean Carbon Fluxes: Science Requirements And Proposed Mission, Joellen L. Russell, David G. Long, Paul Chang, Madeline Cowell, Enrique Curchitser, Michael S. Dinniman, Charles Fellows, Paul Goodman, Eileen Hofmann, Zorana Jelenak, John Klinck, John P. Krasting, Nicole Suzanne Lovenduski, Marcus Lofverstrom, Matthew R. Mazloff, Shelley Petroy, Anjani Polit, Ernesto Rodriguez, Oscar Schofield, Ad Stoffelen, Ronald J. Stouffer, Rik Wanninkhof, Carl Weimer, Xubin Zeng Jan 2021

Measuring Winds From Space To Reduce The Uncertainty In The Southern Ocean Carbon Fluxes: Science Requirements And Proposed Mission, Joellen L. Russell, David G. Long, Paul Chang, Madeline Cowell, Enrique Curchitser, Michael S. Dinniman, Charles Fellows, Paul Goodman, Eileen Hofmann, Zorana Jelenak, John Klinck, John P. Krasting, Nicole Suzanne Lovenduski, Marcus Lofverstrom, Matthew R. Mazloff, Shelley Petroy, Anjani Polit, Ernesto Rodriguez, Oscar Schofield, Ad Stoffelen, Ronald J. Stouffer, Rik Wanninkhof, Carl Weimer, Xubin Zeng

CCPO Publications

Strong winds in Southern Ocean storms drive air-sea carbon and heat fluxes. These fluxes are integral to the global climate system and the wind speeds that drive them are increasing. The current scatterometer constellation measuring vector winds remotely undersamples these storms and the higher winds within them, leading to potentially large biases in Southern Ocean wind reanalyses and the fluxes that derive from them. This observing system design study addresses these issues in two ways. First, we describe an addition to the scatterometer constellation, called Southern Ocean Storms -- Zephyr, to increase the frequency of independent observations, better constraining high …

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Assessment Of Tidal Range Changes In The North Sea From 1958 To 2014, Leon Jänicke, Andra Ebener, Sönke Dangendorf, Arne Arns, Michael Schindelegger, Sebastian Niehüser, Ivan D. Haigh, Philip Woodworth, Jürgen Jensen Jan 2021

Assessment Of Tidal Range Changes In The North Sea From 1958 To 2014, Leon Jänicke, Andra Ebener, Sönke Dangendorf, Arne Arns, Michael Schindelegger, Sebastian Niehüser, Ivan D. Haigh, Philip Woodworth, Jürgen Jensen

CCPO Publications

We document an exceptional large-spatial scale case of changes in tidal range in the North Sea, featuring pronounced trends between -2.3 mm/yr at tide gauges in the United Kingdom and up to 7 mm/yr in the German Bight between 1958 and 2014. These changes are spatially heterogeneous and driven by a superposition of local and large-scale processes within the basin. We use principal component analysis to separate large-scale signals appearing coherently over multiple stations from rather localized changes. We identify two leading principal components (PCs) that explain about 69% of tidal range changes in the entire North Sea including the …

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A Recirculating Eddy Promotes Subsurface Particle Retention In An Antarctic Biological Hotspot, Katherine L. Hudson, Matthew John Oliver, Josh Kohut, Michael S. Dinniman, J. M. Klinck, Carlos Moffat, Hank Statscewich, Kim S. Bernard, William Fraser Jan 2021

A Recirculating Eddy Promotes Subsurface Particle Retention In An Antarctic Biological Hotspot, Katherine L. Hudson, Matthew John Oliver, Josh Kohut, Michael S. Dinniman, J. M. Klinck, Carlos Moffat, Hank Statscewich, Kim S. Bernard, William Fraser

OES Faculty Publications

Palmer Deep Canyon is one of the biological hotspots associated with deep bathymetric features along the Western Antarctic Peninsula. The upwelling of nutrient-rich Upper Circumpolar Deep Water to the surface mixed layer in the submarine canyon has been hypothesized to drive increased phytoplankton biomass productivity, attracting krill, penguins and other top predators to the region. However, observations in Palmer Deep Canyon lack a clear in-situ upwelling signal, lack a physiological response by phytoplankton to Upper Circumpolar Deep Water in laboratory experiments, and surface residence times that are too short for phytoplankton populations to reasonably respond to any locally upwelled nutrients. …

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Constraining 20th‐Century Sea‐Level Rise In The South Atlantic Ocean, Thomas Frederikse, Surendra Adhikari, Tim J. Daley, Sönke Dangendorf, Roland Gehrels, Felix Landerer, Marta Marcos, Thomas L. Newton, Graham Rush, Aimée B.A. Slangen, Guy Wöppelmann Jan 2021

Constraining 20th‐Century Sea‐Level Rise In The South Atlantic Ocean, Thomas Frederikse, Surendra Adhikari, Tim J. Daley, Sönke Dangendorf, Roland Gehrels, Felix Landerer, Marta Marcos, Thomas L. Newton, Graham Rush, Aimée B.A. Slangen, Guy Wöppelmann

OES Faculty Publications

Sea level in the South Atlantic Ocean has only been measured at a small number of tide-gauge locations, which causes considerable uncertainty in 20th-century sea-level trend estimates in this basin. To obtain a better-constrained sea-level trend in the South Atlantic Ocean, this study aims to answer two questions. The first question is: can we combine new observations, vertical land motion estimates, and information on spatial sampling biases to obtain a likely range of 20th-century sea-level rise in the South Atlantic? We combine existing observations with recovered observations from Dakar and a high-resolution sea-level reconstruction based on salt-marsh sediments from the …

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Hybrid Models As Transdisciplinary Research Enablers, Andreas Tolk, Alison Harper, Navonil Mustafee Jan 2021

Hybrid Models As Transdisciplinary Research Enablers, Andreas Tolk, Alison Harper, Navonil Mustafee

Computational Modeling & Simulation Engineering Faculty Publications

Modelling and simulation (M&S) techniques are frequently used in Operations Research (OR) to aid decision-making. With growing complexity of systems to be modelled, an increasing number of studies now apply multiple M&S techniques or hybrid simulation (HS) to represent the underlying system of interest. A parallel but related theme of research is extending the HS approach to include the development of hybrid models (HM). HM extends the M&S discipline by combining theories, methods and tools from across disciplines and applying multidisciplinary, interdisciplinary and transdisciplinary solutions to practice. In the broader OR literature, there are numerous examples of cross-disciplinary approaches in …

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Electroosmotic Mixing Of Non-Newtonian Fluid In A Microchannel With Obstacles And Zeta Potential Heterogeneity, Lanju Mei, Defu Cui, Jiayue Shen, Diganta Dutta, Willie Brown, Lei Zhang, Ibibia K. Dabipi Jan 2021

Electroosmotic Mixing Of Non-Newtonian Fluid In A Microchannel With Obstacles And Zeta Potential Heterogeneity, Lanju Mei, Defu Cui, Jiayue Shen, Diganta Dutta, Willie Brown, Lei Zhang, Ibibia K. Dabipi

Computational Modeling & Simulation Engineering Faculty Publications

This paper investigates the electroosmotic micromixing of non-Newtonian fluid in a microchannel with wall-mounted obstacles and surface potential heterogeneity on the obstacle surface. In the numerical simulation, the full model consisting of the Navier–Stokes equations and the Poisson–Nernst–Plank equations are solved for the electroosmotic fluid field, ion transport, and electric field, and the power law model is used to characterize the rheological behavior of the aqueous solution. The mixing performance is investigated under different parameters, such as electric double layer thickness, flow behavior index, obstacle surface zeta potential, obstacle dimension. Due to the zeta potential heterogeneity at the obstacle surface, …

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Biolability Of Fresh And Photodegraded Pyrogenic Dissolved Organic Matter From Laboratory-Prepared Chars, K. W. Bostick, A. R. Zimmerman, A. I. Goranov, S. Mitra, P. G. Hatcher, A. S. Wozniak Jan 2021

Biolability Of Fresh And Photodegraded Pyrogenic Dissolved Organic Matter From Laboratory-Prepared Chars, K. W. Bostick, A. R. Zimmerman, A. I. Goranov, S. Mitra, P. G. Hatcher, A. S. Wozniak

Chemistry & Biochemistry Faculty Publications

Pyrogenic dissolved organic matter (pyDOM) is known to be an important biogeochemical constituent of aquatic ecosystems and the carbon cycle. While recent studies have examined how pyDOM production, composition, and photolability varies with parent pyrogenic solid material type, we lack an understanding of potential microbial mineralization and transformation of pyDOM in the biogeosphere. Thus, leachates of oak, charred at 400 °C and 650 °C, as well as their photodegraded counterparts were incubated with a soil‐extracted microbial consortium over 96 days. During the incubation, significantly more carbon was biomineralized from the lower versus higher temperature char leachate (45% vs. 37% lost, …

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Synthesis And Self-Assembling Properties Of Peracetylated Β-1 Triazolyl Alkyl D Glucosides And D-Galactosides, Pooja Sharma, Anji Chen, Dan Wang, Guijun Wang Jan 2021

Synthesis And Self-Assembling Properties Of Peracetylated Β-1 Triazolyl Alkyl D Glucosides And D-Galactosides, Pooja Sharma, Anji Chen, Dan Wang, Guijun Wang

Chemistry & Biochemistry Faculty Publications

Carbohydrate-based low-molecular-weight gelators (LMWGs) are useful classes of compounds due to their numerous applications. Among sugar-based LMWGs, certain peracetylated sugar beta-triazole derivatives were found to be effective organogelators and showed interesting self-assembling properties. To further understand the structural influence towards molecular assemblies and obtain new functional materials with interesting properties, we designed and synthesized a library of tetraacetyl beta-1-triazolyl alkyl-D-glucosides and D-galactosides, in which a two or three carbon spacer is inserted between the anomeric position and the triazole moiety. A series of 16 glucose derivatives and 14 galactose derivatives were synthesized and analyzed. The self-assembling properties of these new …

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Fine-Tuning Of Molecular Structures To Generate Carbohydrate Based Super Gelators And Their Applications For Drug Delivery And Dye Absorption, Jonathan Bietsch, Mary Olson, Guijun Wang Jan 2021

Fine-Tuning Of Molecular Structures To Generate Carbohydrate Based Super Gelators And Their Applications For Drug Delivery And Dye Absorption, Jonathan Bietsch, Mary Olson, Guijun Wang

Chemistry & Biochemistry Faculty Publications

Carbohydrate-based low molecular weight gelators (LMWGs) exhibit many desirable properties making them useful in various fields including applications as drug delivery carriers. In order to further understand the structural connection to gelation properties, especially the influence of halide substitutions, we have designed and synthesized a series of para-chlorobenzylidene acetal protected D-glucosamine amide derivatives. Fifteen different amides were synthesized, and their self-assembling properties were assessed in multiple organic solvents, as well as mixtures of organic solvents with water. All derivatives were found to be gelators for at least one solvent and majority formed gels in multiple solvents at concentrations lower than …

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Hidden Markov Model And Cyber Deception For The Prevention Of Adversarial Lateral Movement, Md Ali Reza Al Amin, Sachin Shetty, Laurent Njilla, Deepak K. Tosh, Charles Kamhoua Jan 2021

Hidden Markov Model And Cyber Deception For The Prevention Of Adversarial Lateral Movement, Md Ali Reza Al Amin, Sachin Shetty, Laurent Njilla, Deepak K. Tosh, Charles Kamhoua

Computational Modeling & Simulation Engineering Faculty Publications

Advanced persistent threats (APTs) have emerged as multi-stage attacks that have targeted nation-states and their associated entities, including private and corporate sectors. Cyber deception has emerged as a defense approach to secure our cyber infrastructure from APTs. Practical deployment of cyber deception relies on defenders' ability to place decoy nodes along the APT path optimally. This paper presents a cyber deception approach focused on predicting the most likely sequence of attack paths and deploying decoy nodes along the predicted path. Our proposed approach combines reactive (graph analysis) and proactive (cyber deception technology) defense to thwart the adversaries' lateral movement. The …

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Promoting Diversity In Teaching Cybersecurity Through Gicl, Yuming He, Wu He, Xiaohong Yuan, Li Yang, Theo Bastiaens (Ed.) Jan 2021

Promoting Diversity In Teaching Cybersecurity Through Gicl, Yuming He, Wu He, Xiaohong Yuan, Li Yang, Theo Bastiaens (Ed.)

Information Technology & Decision Sciences Faculty Publications

In summary, it is necessary to develop a diverse group of K-12 students’ interest and skills in cybersecurity as cyber threats continue to grow. Evidence shows that educating the next generation of cyber workers is a crucial job that should begin in elementary school. To ensure the effectiveness of cybersecurity education and equity at the K-12 level, teachers must create thoughtful plans for considering communities’ interests and needs, and to continually reconsider what’s working and how to adjust our strategies, approaches, design, and research plan to meet their specific needs, challenges, and strengths, particularly with students from under-served and underrepresented …

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A Global Ecological Classification Of Coastal Segment Units To Complement Marine Biodiversity Observation Network Assessments, Roger Sayre, Kevin Butler, Keith Van Graafeiland, Sean Breyer, Dawn Wright, Charlie Frye, Deniz Karagulle, Madeline Martin, Jill Cress, Tom Allen, Rebecca J. Allee, Rost Parsons, Bjorn Nyberg, Mark J. Costello, Peter Harris, Frank E. Muller-Karger Jan 2021

A Global Ecological Classification Of Coastal Segment Units To Complement Marine Biodiversity Observation Network Assessments, Roger Sayre, Kevin Butler, Keith Van Graafeiland, Sean Breyer, Dawn Wright, Charlie Frye, Deniz Karagulle, Madeline Martin, Jill Cress, Tom Allen, Rebecca J. Allee, Rost Parsons, Bjorn Nyberg, Mark J. Costello, Peter Harris, Frank E. Muller-Karger

Political Science & Geography Faculty Publications

A new data layer provides Coastal and Marine Ecological Classification Standard (CMECS) labels for global coastal segments at 1 km or shorter resolution. These characteristics are summarized for six US Marine Biodiversity Observation Network (MBON) sites and one MBON Pole to Pole of the Americas site in Argentina. The global coastlines CMECS classifications were produced from a partitioning of a 30 m Landsat-derived shoreline vector that was segmented into 4 million 1 km or shorter segments. Each segment was attributed with values from 10 variables that represent the ecological settings in which the coastline occurs, including properties of the adjacent …

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Anticipating And Adapting To The Future Impacts Of Climate Change On The Health, Security And Welfare Of Low Elevation Coastal Zone (Lecz) Communities In Southeastern Usa, Thomas Allen, Joshua Behr, Anamaria Bukvic, Ryan S.D. Calder, Kiki Caruson, Charles Connor, Christopher D'Elia, David Dismukes, Robin Ersing, Rima Franklin, Jesse Goldstein, Jonathon Goodall, Scott Hemmerling, Jennifer Irish, Steven Lazarus, Derek Loftis, Mark Luther, Leigh Mccallister, Karen Mcglathery, Molly Mitchell, William Moore, Charles Reid Nichols, Karinna Nunez, Matthew Reidenbach, Julie Shortridge, Robert Weisberg, Robert Weiss, Lynn Donelson Wright, Meng Xia, Kehui Xu, Donald Young, Gary Zarillo, Julie C. Zinnert Jan 2021

Anticipating And Adapting To The Future Impacts Of Climate Change On The Health, Security And Welfare Of Low Elevation Coastal Zone (Lecz) Communities In Southeastern Usa, Thomas Allen, Joshua Behr, Anamaria Bukvic, Ryan S.D. Calder, Kiki Caruson, Charles Connor, Christopher D'Elia, David Dismukes, Robin Ersing, Rima Franklin, Jesse Goldstein, Jonathon Goodall, Scott Hemmerling, Jennifer Irish, Steven Lazarus, Derek Loftis, Mark Luther, Leigh Mccallister, Karen Mcglathery, Molly Mitchell, William Moore, Charles Reid Nichols, Karinna Nunez, Matthew Reidenbach, Julie Shortridge, Robert Weisberg, Robert Weiss, Lynn Donelson Wright, Meng Xia, Kehui Xu, Donald Young, Gary Zarillo, Julie C. Zinnert

Political Science & Geography Faculty Publications

Low elevation coastal zones (LECZ) are extensive throughout the southeastern United States. LECZ communities are threatened by inundation from sea level rise, storm surge, wetland degradation, land subsidence, and hydrological flooding. Communication among scientists, stakeholders, policy makers and minority and poor residents must improve. We must predict processes spanning the ecological, physical, social, and health sciences. Communities need to address linkages of (1) human and socioeconomic vulnerabilities; (2) public health and safety; (3) economic concerns; (4) land loss; (5) wetland threats; and (6) coastal inundation. Essential capabilities must include a network to assemble and distribute data and model code to …

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Characterizing Seagrass Effects On Hydrodynamics Of Waves And Currents Through Field Measurements And Computational Modelling, Ramin Familkhalili, Navid Tahvildari Jan 2021

Characterizing Seagrass Effects On Hydrodynamics Of Waves And Currents Through Field Measurements And Computational Modelling, Ramin Familkhalili, Navid Tahvildari

Civil & Environmental Engineering Faculty Publications

Low-lying coastal and estuarine areas are among the most populated regions globally, have high economic significance, and are increasingly threatened by climate change, sea level rise, nuisance flooding, and extreme storms. Nature-based coastal protections are sustainable and sea-level resilient alternatives compared to traditional solutions such as dikes and seawalls. Submerged aquatic vegetation (SAV) or seagrasses can provide coastal flood and erosion protection by attenuating storm wave and current energy and stabilizing seabed sediments. However, more research is needed to understand the interactions between flow, SAVs, and sediments. These dynamic interactions affect flow at different scales and seagrass productivity. In this …

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Efficient Algorithms For Identifying Loop Formation And Computing Θ Value For Solving Minimum Cost Flow Network Problems, Timothy Michael Chávez, Duc Thai Nguyen Jan 2021

Efficient Algorithms For Identifying Loop Formation And Computing Θ Value For Solving Minimum Cost Flow Network Problems, Timothy Michael Chávez, Duc Thai Nguyen

Computational Modeling & Simulation Engineering Faculty Publications

While the minimum cost flow (MCF) problems have been well documented in many publications, due to its broad applications, little or no effort have been devoted to explaining the algorithms for identifying loop formation and computing the value needed to solve MCF network problems. This paper proposes efficient algorithms, and MATLAB computer implementation, for solving MCF problems. Several academic and real-life network problems have been solved to validate the proposed algorithms; the numerical results obtained by the developed MCF code have been compared and matched with the built-in MATLAB function Linprog() (Simplex algorithm) for further validation.

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The Enlightening Role Of Explainable Artificial Intelligence In Chronic Wound Classification, Salih Sarp, Murat Kuzlu, Emmanuel Wilson, Umit Cali, Ozgur Guler Jan 2021

The Enlightening Role Of Explainable Artificial Intelligence In Chronic Wound Classification, Salih Sarp, Murat Kuzlu, Emmanuel Wilson, Umit Cali, Ozgur Guler

Engineering Technology Faculty Publications

Artificial Intelligence (AI) has been among the most emerging research and industrial application fields, especially in the healthcare domain, but operated as a black-box model with a limited understanding of its inner working over the past decades. AI algorithms are, in large part, built on weights calculated as a result of large matrix multiplications. It is typically hard to interpret and debug the computationally intensive processes. Explainable Artificial Intelligence (XAI) aims to solve black-box and hard-to-debug approaches through the use of various techniques and tools. In this study, XAI techniques are applied to chronic wound classification. The proposed model classifies …

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Spatio-Temporal Modelling Of Tick Life-Stage Count Data With Spatially Varying Coefficients, Thabo Lephoto, Henry Mwambi, Oliver Bodhlyera, Holly Gaff Jan 2021

Spatio-Temporal Modelling Of Tick Life-Stage Count Data With Spatially Varying Coefficients, Thabo Lephoto, Henry Mwambi, Oliver Bodhlyera, Holly Gaff

Biological Sciences Faculty Publications

There is a vast amount of geo-referenced data in many fields of study including ecological studies. Geo-referencing is usually by point referencing; that is, latitudes and longitudes or by areal referencing, which includes districts, counties, states, provinces and other administrative units. The availability of large geo-referenced datasets for modelling has necessitated the development and application of spatial statistical methods. However, spatial varying coefficients models exploring the abundance of tick counts remain limited. In this study we used data that was collected and prepared by researchers in the Department of Biological Sciences from the Old Dominion University, Virginia, USA. We modelled …

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Contrasting Heat Stress Response Patterns Of Coral Holobionts Across The Red Sea Suggest Distinct Mechanisms Of Thermal Tolerance, Christian R. Voolstra, Jacob J. Valenzuela, Serdar Turkarslan, Anny Cárdenas, Benjamin C.C. Hume, Gabriela Perna, Carol Buitrago-López, Katherine Rowe, Monica V. Orellana, Nitin S. Baliga, Suman Paranjape, Guilhem Banc-Prandi, Jessica Bellworthy, Moaz Fine, Sarah Frias-Torres, Daniel J. Barshis Jan 2021

Contrasting Heat Stress Response Patterns Of Coral Holobionts Across The Red Sea Suggest Distinct Mechanisms Of Thermal Tolerance, Christian R. Voolstra, Jacob J. Valenzuela, Serdar Turkarslan, Anny Cárdenas, Benjamin C.C. Hume, Gabriela Perna, Carol Buitrago-López, Katherine Rowe, Monica V. Orellana, Nitin S. Baliga, Suman Paranjape, Guilhem Banc-Prandi, Jessica Bellworthy, Moaz Fine, Sarah Frias-Torres, Daniel J. Barshis

Biological Sciences Faculty Publications

Corals from the northern Red Sea, in particular the Gulf of Aqaba (GoA), have exceptionally high bleaching thresholds approaching >5℃ above their maximum monthly mean (MMM) temperatures. These elevated thresholds are thought to be due to historical selection, as corals passed through the warmer Southern Red Sea during recolonization from the Arabian Sea. To test this hypothesis, we determined thermal tolerance thresholds of GoA versus central Red Sea (CRS) Stylophora pistillata corals using multi-temperature acute thermal stress assays to determine thermal thresholds. Relative thermal thresholds of GoA and CRS corals were indeed similar and exceptionally high (~7℃ above MMM). However, …

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Central Equatorial Pacific Cooling During The Last Glacial Maximum, Minda Moriah Monteagudo, Jean Lynch-Stieglitz, Thomas M. Marchitto, Matthew W. Schmidt Jan 2021

Central Equatorial Pacific Cooling During The Last Glacial Maximum, Minda Moriah Monteagudo, Jean Lynch-Stieglitz, Thomas M. Marchitto, Matthew W. Schmidt

OES Faculty Publications

Establishing tropical sea surface temperature (SST) during the Last Glacial Maximum (LGM) is important for constraining equilibrium climate sensitivity to radiative forcing. Until now, there has been little data from the central equatorial Pacific in global compilations, with foraminiferal assemblage‐based estimates suggesting the region was within 1°C of modern temperatures during the LGM. This is in stark contrast to multi‐proxy evidence from the eastern and western Pacific and model simulations which support larger cooling. Here we present the first estimates of glacial SST in the central equatorial Pacific from Mg/Ca in Globigerinoides ruber. Our results show that the central Pacific …

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Pore Water Exchange-Driven Inorganic Carbon Export From Intertidal Salt Marshes, Joeseph J. Tamborski, Meagan Eagle, Barret L. Kurylyk, Kevin D. Kroeger, Zhaoihui Aleck Wang, Paul Henderson, Matthew A. Charette Jan 2021

Pore Water Exchange-Driven Inorganic Carbon Export From Intertidal Salt Marshes, Joeseph J. Tamborski, Meagan Eagle, Barret L. Kurylyk, Kevin D. Kroeger, Zhaoihui Aleck Wang, Paul Henderson, Matthew A. Charette

OES Faculty Publications

Respiration in intertidal salt marshes generates dissolved inorganic carbon (DIC) that is exported to the coastal ocean by tidal exchange with the marsh platform. Understanding the link between physical drivers of water exchange and chemical flux is a key to constraining coastal wetland contributions to regional carbon budgets. The spatial and temporal (seasonal, annual) variability of marsh pore water exchange and DIC export was assessed from a microtidal salt marsh (Sage Lot Pond, Massachusetts). Spatial variability was constrained from 224Ra : 228Th disequilibria across two hydrologic units within the marsh sediments. Disequilibrium between the more soluble 224Ra …

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Lagrangian Betweenness As A Measure Of Bottlenecks In Dynamical Systems With Oceanographic Examples, Enrico Ser-Giacomi, Alberto Baudena, Vincent Rossi, Mick Follows, Sophie Clayton, Ruggero Vasile, Cristóbal López, Emilio Hernández-García Jan 2021

Lagrangian Betweenness As A Measure Of Bottlenecks In Dynamical Systems With Oceanographic Examples, Enrico Ser-Giacomi, Alberto Baudena, Vincent Rossi, Mick Follows, Sophie Clayton, Ruggero Vasile, Cristóbal López, Emilio Hernández-García

OES Faculty Publications

The study of connectivity patterns in networks has brought novel insights across diverse fields ranging from neurosciences to epidemic spreading or climate. In this context, betweenness centrality has demonstrated to be a very effective measure to identify nodes that act as focus of congestion, or bottlenecks, in the network. However, there is not a way to define betweenness outside the network framework. By analytically linking dynamical systems and network theory, we provide a trajectory-based formulation of betweenness, called Lagrangian betweenness, as a function of Lyapunov exponents. This extends the concept of betweenness beyond the context of network theory relating hyperbolic …

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A Kernel-Based Change Detection Method To Map Shifts In Phytoplankton Communities Measured By Flow Cytometry, Corinne Jones, Sophie Clayton, François Ribalet, E. Virginia Armbrust, Zaid Harchaoui Jan 2021

A Kernel-Based Change Detection Method To Map Shifts In Phytoplankton Communities Measured By Flow Cytometry, Corinne Jones, Sophie Clayton, François Ribalet, E. Virginia Armbrust, Zaid Harchaoui

OES Faculty Publications

1. Automated, ship-board flow cytometers provide high-resolution maps of phytoplankton composition over large swaths of the world's oceans. They therefore pave the way for understanding how environmental conditions shape community structure. Identification of community changes along a cruise transect commonly segments the data into distinct regions. However, existing segmentation methods are generally not applicable to flow cytometry data, as these data are recorded as ‘point cloud’ data, with hundreds or thousands of particles measured during each time interval. Moreover, nonparametric segmentation methods that do not rely on prior knowledge of the number of species are desirable to map community shifts. …

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Synoptic Mesoscale To Basin Scale Variability In Biological Productivity And Chlorophyll In The Kuroshio Extension Region, Sophie Clayton, Hilary I. Palevsky, Luanne Thompson, Paul D. Quay Jan 2021

Synoptic Mesoscale To Basin Scale Variability In Biological Productivity And Chlorophyll In The Kuroshio Extension Region, Sophie Clayton, Hilary I. Palevsky, Luanne Thompson, Paul D. Quay

OES Faculty Publications

The Kuroshio current separates from the Japanese coast to become the eastward flowing Kuroshio Extension (KE) characterized by a strong latitudinal density front, high levels of mesoscale (eddy) energy, and high chlorophyll a (Chl). While satellite measurements of Chl show evidence of the impact of mesoscale eddies on the standing stock of phytoplankton, there have been very limited synoptic, spatially resolved in situ estimates of productivity in this region. Here, we present underway measurements of oxygen/argon supersaturation (ΔO2/Ar), a tracer of net biological productivity, for the KE made in spring, summer, and early autumn. We find large seasonal differences in …

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See-Trend: Secure Traffic-Related Event Detection In Smart Communities, Stephan Olariu, Dimitrie C. Popescu Jan 2021

See-Trend: Secure Traffic-Related Event Detection In Smart Communities, Stephan Olariu, Dimitrie C. Popescu

Computer Science Faculty Publications

It has been widely recognized that one of the critical services provided by Smart Cities and Smart Communities is Smart Mobility. This paper lays the theoretical foundations of SEE-TREND, a system for Secure Early Traffic-Related EveNt Detection in Smart Cities and Smart Communities. SEE-TREND promotes Smart Mobility by implementing an anonymous, probabilistic collection of traffic-related data from passing vehicles. The collected data are then aggregated and used by its inference engine to build beliefs about the state of the traffic, to detect traffic trends, and to disseminate relevant traffic-related information along the roadway to help the driving public make informed …

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Bioactive Trace Metals And Their Isotopes As Paleoproductivity Proxies: An Assessment Using Geotraces-Era Data, T. J. Horner, S. H. Little, T. W. Conway, J. R. Farmer, Jennifer E. Hertzberg, D. J. Janssen, A.J.M. Lough, J.L. Mckay, A. Tessin, S.J.G. Galer, S. L. Jaccard, F. Lacan, A. Paytan, K. Wuttig, Geotraces-Pages Biological Productivity Working Group Members Jan 2021

Bioactive Trace Metals And Their Isotopes As Paleoproductivity Proxies: An Assessment Using Geotraces-Era Data, T. J. Horner, S. H. Little, T. W. Conway, J. R. Farmer, Jennifer E. Hertzberg, D. J. Janssen, A.J.M. Lough, J.L. Mckay, A. Tessin, S.J.G. Galer, S. L. Jaccard, F. Lacan, A. Paytan, K. Wuttig, Geotraces-Pages Biological Productivity Working Group Members

OES Faculty Publications

Phytoplankton productivity and export sequester climatically significant quantities of atmospheric carbon dioxide as particulate organic carbon through a suite of processes termed the biological pump. Constraining how the biological pump operated in the past is important for understanding past atmospheric carbon dioxide concentrations and Earth's climate history. However, reconstructing the history of the biological pump requires proxies. Due to their intimate association with biological processes, several bioactive trace metals and their isotopes are potential proxies for past phytoplankton productivity, including iron, zinc, copper, cadmium, molybdenum, barium, nickel, chromium, and silver. Here, we review the oceanic distributions, driving processes, and depositional …

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Neodymium Isotope Geochemistry Of A Subterranean Estuary, Darren A. Chevis, T. Jade Mohajerin, Ningfang Yang, Jaye E. Cable, E. Troy Rasbury, Sidney R. Hemming, David J. Burdige, Jonathan B. Martin, Christopher D. White, Karen H. Johannesson Jan 2021

Neodymium Isotope Geochemistry Of A Subterranean Estuary, Darren A. Chevis, T. Jade Mohajerin, Ningfang Yang, Jaye E. Cable, E. Troy Rasbury, Sidney R. Hemming, David J. Burdige, Jonathan B. Martin, Christopher D. White, Karen H. Johannesson

OES Faculty Publications

Rare earth elements (REE) and Nd isotope compositions of surface and groundwaters from the Indian River Lagoon in Florida were measured to investigate the influence of submarine groundwater discharge (SGD) on these parameters in coastal waters. The Nd flux of the terrestrial component of SGD is around 0.7 ± 0.03 μmol Nd/day per m of shoreline across the nearshore seepage face of the subterranean estuary. This translates to a terrestrial SGD Nd flux of 4 ± 0.2 mmol/day for the entire 5,880 m long shoreline of the studied portion of the lagoon. The Nd flux from bioirrigation across the nearshore …

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Fifteen Years Of Hfc-134a Satellite Observations: Comparisons With Slimcat Calculations, Jeremy J. Harrison, Martyn P. Chipperfield, Christopher D. Boone, Sandip S. Dhomse, Peter F. Bernath Jan 2021

Fifteen Years Of Hfc-134a Satellite Observations: Comparisons With Slimcat Calculations, Jeremy J. Harrison, Martyn P. Chipperfield, Christopher D. Boone, Sandip S. Dhomse, Peter F. Bernath

Chemistry & Biochemistry Faculty Publications

The phase out of anthropogenic ozone-depleting substances such as chlorofluorocarbons under the terms of the Montreal Protocol led to the development and worldwide use of hydrofluorocarbons (HFCs) in refrigeration, air conditioning, and as blowing agents and propellants. Consequently, over recent years, the atmospheric abundances of HFCs have dramatically increased. HFCs are powerful greenhouse gases and are now controlled under the terms of the 2016 Kigali Amendment to the Montreal Protocol. HFC-134a is currently the most abundant HFC in the atmosphere, breaking the 100 ppt barrier in 2018, and can be measured in the Earth's atmosphere by the satellite remote-sensing instrument …

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Energy Renewal: Isothermal Utilization Of Environmental Heat Energy With Asymmetric Structures, James Weifu Lee Jan 2021

Energy Renewal: Isothermal Utilization Of Environmental Heat Energy With Asymmetric Structures, James Weifu Lee

Chemistry & Biochemistry Faculty Publications

Through the research presented herein, it is quite clear that there are two thermodynamically distinct types (A and B) of energetic processes naturally occurring on Earth. Type A, such as glycolysis and the tricarboxylic acid cycle, apparently follows the second law well; Type B, as exemplified by the thermotrophic function with transmembrane electrostatically localized protons presented here, does not necessarily have to be constrained by the second law, owing to its special asymmetric function. This study now, for the first time, numerically shows that transmembrane electrostatic proton localization (Type-B process) represents a negative entropy event with a local protonic entropy …

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Trichome Lengths Of The Heterocystous N2-Fixing Cyanobacteria In The Tropical Marginal Seas Of The Western North Pacific, Sing-How Tuo, Margaret R. Mulholland, Yukiko Taniuchi, Houng-Yung Chen, Wann-Neng Jane, Yen-Huei Lin, Yuh-Ling Lee Chen Jan 2021

Trichome Lengths Of The Heterocystous N2-Fixing Cyanobacteria In The Tropical Marginal Seas Of The Western North Pacific, Sing-How Tuo, Margaret R. Mulholland, Yukiko Taniuchi, Houng-Yung Chen, Wann-Neng Jane, Yen-Huei Lin, Yuh-Ling Lee Chen

OES Faculty Publications

Calothrix rhizosoleniae and Richelia intracellularis are heterocystous cyanobacteria found in the tropical oceans. C. rhizosoleniae commonly live epiphytically on diatom genera Chaetoceros (C-C) and Bacteriastrum (B-C) while R. intracellularis live endosymbiotically within Rhizosolenia (R-R), Guinardia (G-R), and Hemiaulus (H-R); although, they occasionally live freely (FL-C and FL-R). Both species have much shorter trichomes than the other marine filamentous cyanobacteria such as Trichodesmium spp. and Anabaena gerdii. We investigated the trichome lengths of C. rhizosoleniae and R. intracellularis in the South China Sea (SCS) and the Philippine …

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