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Full-Text Articles in Physical Sciences and Mathematics

Predicting Combined Effects Of Land Use And Climate Change On River And Stream Salinity, John Olson Dec 2018

Predicting Combined Effects Of Land Use And Climate Change On River And Stream Salinity, John Olson

John Olson

Agricultural, industrial and urban development have all contributed to increased salinity in streams and rivers, but the likely effects of future development and climate change are unknown. I developed two empirical models
to estimate how these combined effects might affect salinity by the end of this century (measured as electrical conductivity, EC). The first model predicts natural background from static (e.g. geology and soils) and dynamic
(i.e. climate and vegetation) environmental factors and explained 78% of the variation in EC. I then compared the estimated background EC with current measurements at 2001 sites chosen probabilistically from all conterminous USA streams. …


Generating High-Order Optical And Spin Harmonics From Ferromagnetic Monolayers, G.P. Zhang, M.S. Si, M. Murakami, Y.H. Bai, Thomas F. George Nov 2018

Generating High-Order Optical And Spin Harmonics From Ferromagnetic Monolayers, G.P. Zhang, M.S. Si, M. Murakami, Y.H. Bai, Thomas F. George

Thomas George

High-order harmonic generation (HHG) in solids has entered a new phase of intensive research, with envisioned band-structure mapping on an ultrashort time scale. This partly benefits from a flurry of new HHG materials discovered, but so far has missed an important group. HHG in magnetic materials should have profound impact on future magnetic storage technology advances. Here we introduce and demonstrate HHG in ferromagnetic monolayers. We find that HHG carries spin information and sensitively depends on the relativistic spin–orbit coupling; and if they are dispersed into the crystal momentum k space, harmonics originating from real transitions can be k-resolved and …


Intro To Command Line Coding (Fastqe & Fastp), Ray A. Enke Oct 2018

Intro To Command Line Coding (Fastqe & Fastp), Ray A. Enke

Ray Enke Ph.D.

This in class activity is designed for novices as an introduction to command line coding. The activity uses the programs FASTQE and FASTP to analyze the quality and trim Illumina FASTQ sequencing data.


Belowground Rhizomes In Paleosols: The Hidden Half Of An Early Devonian Vascular Plant, Jinzhuang Xue, Zhenzhen Deng, Pu Huang, Kangjun Huang, Michael J. Benton, Ying Cui Oct 2018

Belowground Rhizomes In Paleosols: The Hidden Half Of An Early Devonian Vascular Plant, Jinzhuang Xue, Zhenzhen Deng, Pu Huang, Kangjun Huang, Michael J. Benton, Ying Cui

Ying Cui

The colonization of terrestrial environments by rooted vascular plants had far-reaching impacts on the Earth system. However, the belowground structures of early vascular plants are rarely documented, and thus the plant−soil interactions in early terrestrial ecosystems are poorly understood. Here we report the earliest rooted paleosols (fossil soils) in Asia from Early Devonian deposits of Yunnan, China. Plant traces are extensive within the soil and occur as complex network-like structures, which are interpreted as representing long-lived, belowground rhizomes of the basal lycopsid Drepanophycus. The rhizomes produced large clones and helped the plant survive frequent sediment burial in well-drained soils …


D_Luftig_Data_Management_Slides.Pdf, David Luftig Oct 2018

D_Luftig_Data_Management_Slides.Pdf, David Luftig

David Luftig

These are the slides used for 10/24/2018 workshop "Campus Conversation: On-Campus Resources for Federal Grant Seekers."


Tiered Approaches In Analyzing Rice Field Pesticide Fate And Transport For Ecological Risk Assessment, Ruoyu Wang Jul 2018

Tiered Approaches In Analyzing Rice Field Pesticide Fate And Transport For Ecological Risk Assessment, Ruoyu Wang

Ruoyu Wang

No abstract provided.


Conjugation Of Nanomaterials And Nematic Liquid Crystals For Futuristic Applications And Biosensors, Thomas F. George, Amit Choudhary, Guoqiang Li Jul 2018

Conjugation Of Nanomaterials And Nematic Liquid Crystals For Futuristic Applications And Biosensors, Thomas F. George, Amit Choudhary, Guoqiang Li

Thomas George

The established role of nematic liquid crystals (NLCs) in the recent rapid development of displays has motivated researchers to modulate the electro-optical properties of LCs. Furthermore, adding nanomaterials into NLCs has led to enhancements of the properties of NLCs, like reduced threshold of the operating voltage, variation in pretilt angle, reduced switching time, etc. These enhanced properties, due to interfacial dynamics, are enabling wider applications of NLCs and nanomaterials. The recent literature of nanomaterial-doped NLCs is rich with various kinds of nanomaterials in a variety of NLCs. The light has been focused on the most widely used and studied gold …


Space Operations In The Suborbital Space Flight Simulator And Mission Control Center: Lessons Learned With Xcor Lynx, Pedro Llanos, Christopher Nguyen, David Williams, Kim O. Chambers Ph.D., Erik Seedhouse, Robert Davidson May 2018

Space Operations In The Suborbital Space Flight Simulator And Mission Control Center: Lessons Learned With Xcor Lynx, Pedro Llanos, Christopher Nguyen, David Williams, Kim O. Chambers Ph.D., Erik Seedhouse, Robert Davidson

Pedro J. Llanos (www.AstronauticsLlanos.com)

This study was conducted to better understand the performance of the XCOR Lynx vehicle. Because the Lynx development was halted, the best knowledge of vehicle dynamics can only be found through simulator flights. X-Plane 10 was chosen for its robust applications and accurate portrayal of dynamics on a vehicle in flight. The Suborbital Space Flight Simulator (SSFS) and Mission Control Center (MCC) were brought to the Applied Aviation Sciences department in fall 2015 at Embry-Riddle Aeronautical University, Daytona Beach campus. This academic and research tool is a department asset capable of providing multiple fields of data about suborbital simulated flights. …


Computer Vision Evidence Supporting Craniometric Alignment Of Rat Brain Atlases To Streamline Expert-Guided, First-Order Migration Of Hypothalamic Spatial Datasets Related To Behavioral Control, Arshad M. Khan, Jose G. Perez, Claire E. Wells, Olac Fuentes Apr 2018

Computer Vision Evidence Supporting Craniometric Alignment Of Rat Brain Atlases To Streamline Expert-Guided, First-Order Migration Of Hypothalamic Spatial Datasets Related To Behavioral Control, Arshad M. Khan, Jose G. Perez, Claire E. Wells, Olac Fuentes

Arshad M. Khan, Ph.D.

The rat has arguably the most widely studied brain among all animals, with numerous reference atlases for rat brain having been published since 1946. For example, many neuroscientists have used the atlases of Paxinos and Watson (PW, first published in 1982) or Swanson (S, first published in 1992) as guides to probe or map specific rat brain structures and their connections. Despite nearly three decades of contemporaneous publication, no independent attempt has been made to establish a basic framework that allows data mapped in PW to be placed in register with S, or vice versa. …


Shaping Light In Backward-Wave Nonlinear Hyperbolic Metamaterials, Thomas F. George, Alexander K. Popov, Sergey A. Myslivets, Vitaly V. Slabko, Victor A. Tkachenko Apr 2018

Shaping Light In Backward-Wave Nonlinear Hyperbolic Metamaterials, Thomas F. George, Alexander K. Popov, Sergey A. Myslivets, Vitaly V. Slabko, Victor A. Tkachenko

Thomas George

Backward electromagnetic waves are extraordinary waves with contra-directed phase velocity and energy flux. Unusual properties of the coherent nonlinear optical coupling of the phase-matched ordinary and backward electromagnetic waves with contra-directed energy fluxes are described that enable greatly-enhanced frequency and propagation direction conversion, parametrical amplification, as well as control of shape of the light pulses. Extraordinary transient processes that emerge in such metamaterials in pulsed regimes are described. The results of the numerical simulation of particular plasmonic metamaterials with hyperbolic dispersion are presented, which prove the possibility to match phases of such coupled guided ordinary and backward electromagnetic waves. Particular …


Modification Of Purine And Pyrimidine Nucleosides By Direct C-H Bond Activation, Yong Liang, Stanislaw F. Wnuk Apr 2018

Modification Of Purine And Pyrimidine Nucleosides By Direct C-H Bond Activation, Yong Liang, Stanislaw F. Wnuk

Stanislaw Wnuk

Transition metal-catalyzed modifications of the activated heterocyclic bases of nucleosides as well as DNA or RNA fragments employing traditional cross-coupling methods have been well-established in nucleic acid chemistry. This review covers advances in the area of cross-coupling reactions in which nucleosides are functionalized via direct activation of the C8-H bond in purine and the C5-H or C6-H bond in uracil bases. The review focuses on Pd/Cu-catalyzed couplings between unactivated nucleoside bases with aryl halides. It also discusses cross-dehydrogenative arylations and alkenylations as well as other reactions used for modification of nucleoside bases that avoid the use of organometallic precursors and …


Climate Change, Cattle, And The Challenge Of Sustainability In A Telecoupled System In Africa, Tara S. Easter, Alexander K. Killion, Neil H. Carter Mar 2018

Climate Change, Cattle, And The Challenge Of Sustainability In A Telecoupled System In Africa, Tara S. Easter, Alexander K. Killion, Neil H. Carter

Neil H. Carter

Information, energy, and materials are flowing over greater distances than in the past, changing the structure and feedbacks within and across coupled human and natural systems worldwide. The telecoupling framework was recently developed to understand the feedbacks and multidirectional flows characterizing social and environmental interactions between distant systems. We extend the application of the telecoupling framework to illustrate how flows in beef affect and are affected by social-ecological processes occurring between distant systems in Africa, and how those dynamics will likely change over the next few decades because of climate-induced shifts in a major bovine disease, trypanosomosis. The disease is …


Cropland Expansion Into Prairie Pothole Wetlands, 2001-2010, Carol A. Johnston Feb 2018

Cropland Expansion Into Prairie Pothole Wetlands, 2001-2010, Carol A. Johnston

Carol Johnston

No abstract provided.


Remote Sensing Of Seasonal Changes And Disturbances In Mangrove Forest: A Case Study From South Florida, Keqi Zhang, Bina Thapa, Michael S. Ross, Daniel Gann Feb 2018

Remote Sensing Of Seasonal Changes And Disturbances In Mangrove Forest: A Case Study From South Florida, Keqi Zhang, Bina Thapa, Michael S. Ross, Daniel Gann

Daniel Gann

Knowledge of the spatial and temporal changes caused by episodic disturbances and seasonal variability is essential for understanding the dynamics of mangrove forests at the landscape scale, and for building a baseline that allows detection of the effects of future environmental change. In combination with LiDAR data, we calculated four vegetation indices from 150 Landsat TM images from 1985 to 2011 in order to detect seasonal changes and distinguish them from disturbances due to hurricanes and chilling events in a mangrove-dominated coastal landscape. We found that normalized difference moisture index (NDMI) performed best in identifying both seasonal and event-driven episodic …


Lysine Biosynthesis In Bacteria: A Metallodesuccinylase As A Potential Antimicrobial Target, Danuta M. Gillner, Daniel P. Becker Ph.D., Richard C. Holz Feb 2018

Lysine Biosynthesis In Bacteria: A Metallodesuccinylase As A Potential Antimicrobial Target, Danuta M. Gillner, Daniel P. Becker Ph.D., Richard C. Holz

Richard C. Holz

In this review, we summarize the recent literature on dapE-encoded N-succinyl-l,l-diaminopimelic acid desuccinylase (DapE) enzymes, with an emphasis on structure–function studies that provide insight into the catalytic mechanism. Crystallographic data have also provided insight into residues that might be involved in substrate and hence inhibitor recognition and binding. These data have led to the design and synthesis of several new DapE inhibitors, which are described along with what is known about how inhibitors interact with the active site of DapE enzymes, including the efficacy of a moderately strong DapE inhibitor.


The Fossilized Birth-Death Model For The Analysis Of Stratigraphic Range Data Under Different Speciation Modes, Tanja Stadler, Alexandra Gavryushkina, Rachel C. M. Warnock, Alexei J. Drummond, Tracy A. Heath Feb 2018

The Fossilized Birth-Death Model For The Analysis Of Stratigraphic Range Data Under Different Speciation Modes, Tanja Stadler, Alexandra Gavryushkina, Rachel C. M. Warnock, Alexei J. Drummond, Tracy A. Heath

Tracy Heath

A birth-death-sampling model gives rise to phylogenetic trees with samples from the past and the present. Interpreting “birth” as branching speciation, “death” as extinction, and “sampling” as fossil preservation and recovery, this model – also referred to as the fossilized birth-death (FBD) model – gives rise to phylogenetic trees on extant and fossil samples. The model has been mathematically analyzed and successfully applied to a range of datasets on different taxonomic levels, such as penguins, plants, and insects. However, the current mathematical treatment of this model does not allow for a group of temporally distinct fossil specimens to be assigned …


The Role Of Environmental Filtering In Structuring Appalachian Tree Communities: Topographic Influences On Functional Diversity Are Mediated Through Soil Characteristics, Julia I. Chapman, Ryan W. Mcewan Jan 2018

The Role Of Environmental Filtering In Structuring Appalachian Tree Communities: Topographic Influences On Functional Diversity Are Mediated Through Soil Characteristics, Julia I. Chapman, Ryan W. Mcewan

Ryan McEwan

Identifying the drivers of community assembly has long been a central goal in ecology, and the development of functional diversity indices has provided a new way of detecting the influence of environmental gradients on biotic communities. For an old-growth Appalachian forest, we used path analysis to understand how patterns of tree functional diversity relate to topography and soil gradients and to determine whether topographic effects are mediated through soil chemistry. All of our path models supported the idea of environmental filtering: stressful areas (high elevation, low soil moisture, low soil nutrients) were occupied by communities of low functional diversity, which …


Fast And Space-Efficient Location Of Heavy Or Dense Segments In Run-Length Encoded Sequences, Ronald I. Greenberg Jan 2018

Fast And Space-Efficient Location Of Heavy Or Dense Segments In Run-Length Encoded Sequences, Ronald I. Greenberg

Ronald Greenberg

This paper considers several variations of an optimization problem with potential applications in such areas as biomolecular sequence analysis and image processing. Given a sequence of items, each with a weight and a length, the goal is to find a subsequence of consecutive items of optimal value, where value is either total weight or total weight divided by total length. There may also be a specified lower and/or upper bound on the acceptable length of subsequences. This paper shows that all the variations of the problem are solvable in linear time and space even with non-uniform item lengths and divisible …