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2017

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Articles 181 - 210 of 12520

Full-Text Articles in Physical Sciences and Mathematics

Assessing And Enhancing Nuclear Safety And Security Culture For Small Facilities That Handle Radioactive Material, Solymosi Máté Dec 2017

Assessing And Enhancing Nuclear Safety And Security Culture For Small Facilities That Handle Radioactive Material, Solymosi Máté

International Journal of Nuclear Security

The use of radioactive sources is expanding all over the world and abreast the necessity of the enhancement of its safe and secure application is increasing too. In the nuclear industry, the safety and security are top priorities since decades. They share the same goal, to protect humans from the negative affect of the ionizing radiation. The human component of them is a significant factor and technical solutions can protect us so far and thus the culture for safety and security become a major focus. On the other hand, there are still some contradiction between recommendations and international guidance of …


The Future Of Nuclear Security In Moroccan Territory After The Creation Of The New Moroccan Agency Of Nuclear And Radiological Safety And Security: Opportunities And Challenges, Amal Touarsi, Amina Kharchaf Dec 2017

The Future Of Nuclear Security In Moroccan Territory After The Creation Of The New Moroccan Agency Of Nuclear And Radiological Safety And Security: Opportunities And Challenges, Amal Touarsi, Amina Kharchaf

International Journal of Nuclear Security

Nowadays, a security regime for protecting nuclear and radiological material—providing an intelligent national regulatory institution and establishing national security laws—is necessary in order for a state to ensure security of nuclear and radiological materials used within its borders.

This paper focuses on discussing the opportunities and challenges facing the future of nuclear security after the creation of the new Moroccan Agency of Nuclear and Radiological Safety and Security.


System Optimization And Iterative Image Reconstruction In Photoacoustic Computed Tomography For Breast Imaging, Yang Lou Dec 2017

System Optimization And Iterative Image Reconstruction In Photoacoustic Computed Tomography For Breast Imaging, Yang Lou

McKelvey School of Engineering Theses & Dissertations

Photoacoustic computed tomography(PACT), also known as optoacoustic tomography (OAT), is an emerging imaging technique that has developed rapidly in recent years. The combination of the high optical contrast and the high acoustic resolution of this hybrid imaging technique makes it a promising candidate for human breast imaging, where conventional imaging techniques including X-ray mammography, B-mode ultrasound, and MRI suffer from low contrast, low specificity for certain breast types, and additional risks related to ionizing radiation. Though significant works have been done to push the frontier of PACT breast imaging, it is still challenging to successfully build a PACT breast imaging …


Abiotic- And Biotic-Formation Of Manganese Oxides And Their Fate In Environmental Systems, Haesung Jung Dec 2017

Abiotic- And Biotic-Formation Of Manganese Oxides And Their Fate In Environmental Systems, Haesung Jung

McKelvey School of Engineering Theses & Dissertations

Manganese (hydr)oxide (Mn (hydr)oxide) minerals are ubiquitous in aquatic and terrestrial environments. These minerals have high surface areas and are highly sorptive and redox active. From decades of accumulated knowledge about natural redox cycling, we have found that Mn (hydr)oxides play critical roles as electron donors and acceptors in elemental geochemical cycling and biological metabolisms in nature. Thus, Mn (hydr)oxides have garnered increasing interest to understand natural systems. Considering the variety of redox reactions with Mn (hydr)oxides in nature, it is also expected that there should be diverse pathways to form Mn (hydr)oxides through abiotic and biotic processes. Previous studies …


Untangling The Mechanics Of Co-Entangled Cytoskeletal Networks, Shea Ricketts Dec 2017

Untangling The Mechanics Of Co-Entangled Cytoskeletal Networks, Shea Ricketts

Undergraduate Honors Theses

Active networks of interlinked protein filaments comprising the cytoskeleton largely control cellular mechanics and cell architecture. By forming cytoskeleton networks that combine motile, semiflexible actin with rigid, supportive microtubules, cells maintain structural integrity and shape while being able to flow and move. To elucidate the complex mechanical processes that arise between interacting networks of actin and microtubules within cells, we create a suite of randomly-oriented, well mixed networks of actin and microtubules by co-polymerizing varying ratios of both proteins in situ. We use optical tweezer microrheology in order to characterize the nonlinear mesoscale mechanics of in vitro co-entangled actin-microtubule composites. …


New Implementations For Tabulating Pseudoprimes And Liars, Wuyang Liu Dec 2017

New Implementations For Tabulating Pseudoprimes And Liars, Wuyang Liu

Honors Projects

Whether it is applied to primality test or cryptography, pseudoprimes are one of the most important topics in number theory. Regarding the study of strong pseudoprimes, there are two problems which mathematicians have been working on:
1. Given a, b, find all a-spsp up to b.
2. Given an odd composite n, find all a -n such that n is an a-spsp.
where n = a-spsp means n is a strong pseudoprime to base a, and a is a strong liar of n.

The two problems are respectively referred to as …


Can Addressing Language Skills For Fifth Grade Ells In A Multiplication Curriculum Help Address The Achievement Gap In Math? A Multiplication Workbook For Big Kids, Michelle Douglas Dec 2017

Can Addressing Language Skills For Fifth Grade Ells In A Multiplication Curriculum Help Address The Achievement Gap In Math? A Multiplication Workbook For Big Kids, Michelle Douglas

Master's Projects and Capstones

Currently, the state of California has 1,332,405 students from grades k-12 who speak a language other than English at home (Caledfacts, 2016). When I started my first year teaching fifth grade with 95% of my students being English language learners (ELLs), I was surprised to see an achievement gap of two to three years in my student’s reading and math skills. I found that my student’s developmental language and math skills contributed to a lack of engagement during math time. Upon further research, I found that these three factors play a role in the wide achievement gaps between ELLs and …


Remediation Strategies For Mercury Contaminated Lakes And Reservoirs Within The State Of California, Emily Chortek Dec 2017

Remediation Strategies For Mercury Contaminated Lakes And Reservoirs Within The State Of California, Emily Chortek

Master's Projects and Capstones

Mercury is an environmental and public health concern due to its neurodegenerative effects and ubiquitous concentration within the environment. To mitigate these risks and reduce concentrations within the environment, remediation methods are necessary. The purpose of this paper is to investigate and evaluate the efficacy of a number of remediation options for mercury contaminated lakes and reservoirs in the State of California. This paper also identifies a number of challenges associated with the implementation of each method and provides recommendations for environmental managers to use when remediating mercury contaminated lakes. Hypolimnetic oxygenation (HOS) was found to be the least problematic …


Environmental Ngo-Private Sector Partnerships: A Tool To Generate Business Value And Protect The Natural World, Carolyn Nogy Nogy Dec 2017

Environmental Ngo-Private Sector Partnerships: A Tool To Generate Business Value And Protect The Natural World, Carolyn Nogy Nogy

Master's Projects and Capstones

Many environmental challenges are complicated by complex and social, cultural, economic and political interactions, which are difficult to address by a single entity. However, partnerships can offer the necessary depth and versatility to address them effectively. By working together, there is an opportunity for cross sector partners to leverage their unique expertise, while blending resources to achieve more comprehensive and sustainable solutions to existing environmental problems. This project examines the use of partnerships between environmental NGOs and the private sector to manage complex environmental problems, providing a critical assessment of the partnership attributes that generate the most mutual benefit. The …


Planning Cities, Economically Or Communally: A Comparative Study Of Amsterdam And San Francisco, Raina Dawn Whittekiend Dec 2017

Planning Cities, Economically Or Communally: A Comparative Study Of Amsterdam And San Francisco, Raina Dawn Whittekiend

Master's Theses

Globalization has spun “community” off its axis. What once defined community is no longer the current state of the community. Increased economic transactions have led to the instability of communities that once depended on one another at the local level. These communities are now dependent on systems that do not know nor understand their actors. This lack of relationship between development and subject is witnessed and highly scrutinized in developing countries all over the world and has been intensely researched in academic literature. This thesis intends to better understand why in modernized global cities these same processes of development and …


Best Practices For Test Driven Development, Timothy Tacker Dec 2017

Best Practices For Test Driven Development, Timothy Tacker

All Student Theses and Dissertations

In his award-winning book, Test-driven Development By Example, Kent Beck wrote, "Clean code that works...is the goal of Test-driven Development (TDD)." TDD is a style of software development that first begins with the creation of tests and then makes use short, iterative development cycles until all test requirements are fulfilled. In order to provide the reader with sufficient background to understand the concepts discussed, this thesis begins by presenting a detailed description of this style of development. TDD is then contrasted with other popular styles, with a focus toward highlighting the many benefits this style offers over the others. This …


Boulder Distribution Analysis Of Impact Craters In The Tharsis Region And Elysium Planitia, Mars, Nicole Button Dec 2017

Boulder Distribution Analysis Of Impact Craters In The Tharsis Region And Elysium Planitia, Mars, Nicole Button

LSU Master's Theses

Crater counting is an accepted method for dating the surface of a planetary body. An older landscape will have a higher areal density of craters due to exposure of impacts occurring over a longer time period. Since each initial impact only forms one primary crater, secondary craters need to be excluded in the crater counting method to appropriately catalog only distinct impact events. However, small primary craters may be difficult to distinguish from secondary craters. Understanding physical features of impact craters, such as the ejecta blanket, would improve the planetary community’s ability to differentiate between the two types of craters. …


Structured Illumination Diffuse Optical Tomography For Mouse Brain Imaging, Matthew Reisman Dec 2017

Structured Illumination Diffuse Optical Tomography For Mouse Brain Imaging, Matthew Reisman

Arts & Sciences Electronic Theses and Dissertations

As advances in functional magnetic resonance imaging (fMRI) have transformed the study of human brain function, they have also widened the divide between standard research techniques used in humans and those used in mice, where high quality images are difficult to obtain using fMRI given the small volume of the mouse brain. Optical imaging techniques have been developed to study mouse brain networks, which are highly valuable given the ability to study brain disease treatments or development in a controlled environment. A planar imaging technique known as optical intrinsic signal (OIS) imaging has been a powerful tool for capturing functional …


First Low-Frequency Einstein@Home All-Sky Search For Continuous Gravitational Waves In Advanced Ligo Data, B. P. Abbott, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, C. Adams, T. Adams, P. Addesso, R. X. Adhikari, V. B. Adya, C. Affeldt, M. Afrough, B. Agarwal, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, B. Allen, G. Allen, A. Allocca, P. A. Altin, A. Amato, A. Ananyeva, S. B. Anderson, W. G. Anderson, S. Antier, S. Appert, K. Arai, M. C. Araya Dec 2017

First Low-Frequency Einstein@Home All-Sky Search For Continuous Gravitational Waves In Advanced Ligo Data, B. P. Abbott, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, C. Adams, T. Adams, P. Addesso, R. X. Adhikari, V. B. Adya, C. Affeldt, M. Afrough, B. Agarwal, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, B. Allen, G. Allen, A. Allocca, P. A. Altin, A. Amato, A. Ananyeva, S. B. Anderson, W. G. Anderson, S. Antier, S. Appert, K. Arai, M. C. Araya

Physics and Astronomy Faculty Publications and Presentations

We report results of a deep all-sky search for periodic gravitational waves from isolated neutron stars in data from the first Advanced LIGO observing run. This search investigates the low frequency range of Advanced LIGO data, between 20 and 100 Hz, much of which was not explored in initial LIGO. The search was made possible by the computing power provided by the volunteers of the Einstein@Home project. We find no significant signal candidate and set the most stringent upper limits to date on the amplitude of gravitational wave signals from the target population, corresponding to a sensitivity depth of 48.7 …


A Spatio-Temporal Approach To Mitigate Automotive Radar Spoofing Attacks, Prateek Kapoor Dec 2017

A Spatio-Temporal Approach To Mitigate Automotive Radar Spoofing Attacks, Prateek Kapoor

Graduate Dissertations and Theses

Cyber-physical system (CPS) has become an integral part of human life, ranging from aircraft to health care systems. The security of these critical components ensures its wider acceptability. Traditionally, many works to secure cyber-physical system (CPS) has been done in the cyber domain, like securing inter/intra CPS communication, securing the exposed software, rebuilding control input derived from sensor data post-digitization, using sensor fusion. All of this security software suffers from a basic attack wherein an attacker compromises the physical/analog sensing system. Researchers have made some progress in mitigating such attacks on physical/analog signals of CPS, the current state of the …


First Narrow-Band Search For Continuous Gravitational Waves From Known Pulsars In Advanced Detector Data, B. P. Abbott, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, C. Adams, T. Adams, P. Addesso, R. X. Adhikari, V. B. Adya, C. Affeldt, M. Afrough, B. Agarwal, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, B. Allen, G. Allen, A. Allocca, P. A. Altin, A. Amato, A. Ananyeva, S. B. Anderson, W. G. Anderson, S. V. Angelova, S. Antier, S. Appert Dec 2017

First Narrow-Band Search For Continuous Gravitational Waves From Known Pulsars In Advanced Detector Data, B. P. Abbott, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, C. Adams, T. Adams, P. Addesso, R. X. Adhikari, V. B. Adya, C. Affeldt, M. Afrough, B. Agarwal, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, B. Allen, G. Allen, A. Allocca, P. A. Altin, A. Amato, A. Ananyeva, S. B. Anderson, W. G. Anderson, S. V. Angelova, S. Antier, S. Appert

Physics and Astronomy Faculty Publications and Presentations

Spinning neutron stars asymmetric with respect to their rotation axis are potential sources of continuous gravitational waves for ground-based interferometric detectors. In the case of known pulsars a fully coherent search, based on matched filtering, which uses the position and rotational parameters obtained from electromagnetic observations, can be carried out. Matched filtering maximizes the signal-to-noise (SNR) ratio, but a large sensitivity loss is expected in case of even a very small mismatch between the assumed and the true signal parameters. For this reason, narrow-band analysis methods have been developed, allowing a fully coherent search for gravitational waves from known pulsars …


Multiscale Imaging Of The Mouse Cortex Using Two-Photon Microscopy And Wide-Field Illumination, Jonathan Richard Bumstead Dec 2017

Multiscale Imaging Of The Mouse Cortex Using Two-Photon Microscopy And Wide-Field Illumination, Jonathan Richard Bumstead

McKelvey School of Engineering Theses & Dissertations

The mouse brain can be studied over vast spatial scales ranging from microscopic imaging of single neurons to macroscopic measurements of hemodynamics acquired over the majority of the mouse cortex. However, most neuroimaging modalities are limited by a fundamental trade-off between the spatial resolution and the field-of-view (FOV) over which the brain can be imaged, making it difficult to fully understand the functional and structural architecture of the healthy mouse brain and its disruption in disease. My dissertation has focused on developing multiscale optical systems capable of imaging the mouse brain at both microscopic and mesoscopic spatial scales, specifically addressing …


Locality-Aware Concurrency Platforms, Jordyn Chrystopher Raymond Maglalang Dec 2017

Locality-Aware Concurrency Platforms, Jordyn Chrystopher Raymond Maglalang

McKelvey School of Engineering Theses & Dissertations

Modern computing systems from all domains are becoming increasingly more parallel. Manufacturers are taking advantage of the increasing number of available transistors by packaging more and more computing resources together on a single chip or within a single system. These platforms generally contain many levels of private and shared caches in addition to physically distributed main memory. Therefore, some memory is more expensive to access than other and high-performance software must consider memory locality as one of the first level considerations.

Memory locality is often difficult for application developers to consider directly, however, since many of these NUMA affects are …


Knowledge Driven Approaches And Machine Learning Improve The Identification Of Clinically Relevant Somatic Mutations In Cancer Genomics, Benjamin John Ainscough Dec 2017

Knowledge Driven Approaches And Machine Learning Improve The Identification Of Clinically Relevant Somatic Mutations In Cancer Genomics, Benjamin John Ainscough

Arts & Sciences Electronic Theses and Dissertations

For cancer genomics to fully expand its utility from research discovery to clinical adoption, somatic variant detection pipelines must be optimized and standardized to ensure identification of clinically relevant mutations and to reduce laborious and error-prone post-processing steps. To address the need for improved catalogues of clinically and biologically important somatic mutations, we developed DoCM, a Database of Curated Mutations in Cancer (http://docm.info), as described in Chapter 2. DoCM is an open source, openly licensed resource to enable the cancer research community to aggregate, store and track biologically and clinically important cancer variants. DoCM is currently comprised of 1,364 variants …


Investigation Of Neonatal Pulmonary Structure And Function Via Proton And Hyperpolarized Gas Magnetic Resonance Imaging, Nara Savoye Higano Dec 2017

Investigation Of Neonatal Pulmonary Structure And Function Via Proton And Hyperpolarized Gas Magnetic Resonance Imaging, Nara Savoye Higano

Arts & Sciences Electronic Theses and Dissertations

Magnetic resonance imaging (MRI) is a modality that utilizes the phenomenon of nuclear magnetic resonance (NMR) to yield tomographic images of the body. Proton (1H) MRI has historically been successful in soft tissues but has suffered in the lung due to a variety of technical challenges, such as the low proton-density, rapid T2* relaxation time of the lung parenchymal tissue, and inherent physiological motion in the chest. Recent developments in radial ultrashort echo time (UTE) MRI have in part overcome these issues. In addition, there has been much progress in techniques for hyperpolarization of noble gases (3He and 129Xe) out …


Fast Monte Carlo Simulations For Quality Assurance In Radiation Therapy, Yuhe Wang Dec 2017

Fast Monte Carlo Simulations For Quality Assurance In Radiation Therapy, Yuhe Wang

Arts & Sciences Electronic Theses and Dissertations

Monte Carlo (MC) simulation is generally considered to be the most accurate method for dose calculation in radiation therapy. However, it suffers from the low simulation efficiency (hours to days) and complex configuration, which impede its applications in clinical studies. The recent rise of MRI-guided radiation platform (e.g. ViewRay’s MRIdian system) brings urgent need of fast MC algorithms because the introduced strong magnetic field may cause big errors to other algorithms. My dissertation focuses on resolving the conflict between accuracy and efficiency of MC simulations through 4 different approaches: (1) GPU parallel computation, (2) Transport mechanism simplification, (3) Variance reduction, …


The Chemistry And Biology Of Iron-Scavenging Natural Products From Pathogenic Acinetobacter Baumannii, Justin Shapiro Dec 2017

The Chemistry And Biology Of Iron-Scavenging Natural Products From Pathogenic Acinetobacter Baumannii, Justin Shapiro

Arts & Sciences Electronic Theses and Dissertations

Multidrug resistant (MDR) Gram-negative bacteria represent a global health crisis. Traditional antibiotics create selective pressure and breed resistance, making our current drugs less and less effective. Targeting of bacterial virulence factors has gained interest as an alternative strategy to potentially circumvent this problem. Virulent Acinetobacter baumannii synthesize and secrete pre-acinetobactin, a small molecule metal chelator that scavenges life-sustaining iron and is critical for establishing infection. The work described herein sheds light on the unusual properties of a non-enzymatic isomerization from pre-acinetobactin to acinetobactin and proposes a siderophore-swapping mechanism by which A. baumannii expands its pH window for virulence. Knowledge from …


New Ventures In Amidine-Based Catalyst Design, Nicholas Alan Ahlemeyer Dec 2017

New Ventures In Amidine-Based Catalyst Design, Nicholas Alan Ahlemeyer

Arts & Sciences Electronic Theses and Dissertations

Two new cascade transformations of α,β-unsaturated thioesters catalyzed by amidine-based catalysts have been developed. First, a reagent-free transformation of o-formylaryl cinnamoyl thioesters catalyzed by HBTM-2 to produce 2-substituted thiochromenes achieved high enantioselectivities and yields while forming carbon dioxide as the only byproduct. Second, a highly diastereo- and enantioselective tandem rearrangement of less reactive enone thioesters into tricyclic thiochromanes in the presence of electron-rich amidine-based catalysts was developed. These catalysts were designed with the help of DFT calculations. H-PIP, the first chiral amidine-based catalyst synthesized in our group, performed the best overall in the thiochromane synthesis.

The second chapter of this …


Land Use Land Cover Change Effects On Southern Great Plains Precipitation, Alexandra Caruthers Dec 2017

Land Use Land Cover Change Effects On Southern Great Plains Precipitation, Alexandra Caruthers

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Great Plains land use has changed substantially over the last 160 years, altering the properties of the land through increased settlement and advances in irrigation. Changing the interface between the land and atmosphere has implications for the atmospheric boundary layer, the regional circulation, the local surface energy budget and resulting precipitation patterns. Land use land cover (LULC) changes are an important topic for this region due to its heavy dependence on agriculture. This study investigates differences in Southern Great Plains precipitation patterns between four LULC scenarios: the pre-settlement, 1920’s, Dust Bowl and present day eras. Using the Weather Research and …


Fabrication And Modification Of Titania Nanotube Arrays For Harvesting Solar Energy And Drug Delivery Applications, Ahmed El Ruby Abdel Rahman Mohamed Dec 2017

Fabrication And Modification Of Titania Nanotube Arrays For Harvesting Solar Energy And Drug Delivery Applications, Ahmed El Ruby Abdel Rahman Mohamed

Electronic Thesis and Dissertation Repository

The fast diminishing of fossil fuels in the near future, as well as the global warming caused by increasing greenhouse gases have motivated the urgent quest to develop advanced materials as cost-effective photoanodes for solar light harvesting and many other photocatalytic applications. Recently, titania nanotube arrays (TNTAs) fabricated by anodization process has attracted great interest due to their excellent properties such as: high surface area, vertically oriented, highly organized, one-dimensional, nanotubular structure, photoactivity, chemical stability and biocompatibility. This unique combination of excellent properties makes TNTAs an excellent photoanode for solar light harvesting. However, the relatively wide band gap energy of …


Polarimetric Synthetic Aperture Radar (Sar) Application For Geological Mapping And Resource Exploration In The Canadian Arctic, Byung-Hun Choe Dec 2017

Polarimetric Synthetic Aperture Radar (Sar) Application For Geological Mapping And Resource Exploration In The Canadian Arctic, Byung-Hun Choe

Electronic Thesis and Dissertation Repository

The role of remote sensing in geological mapping has been rapidly growing by providing predictive maps in advance of field surveys. Remote predictive maps with broad spatial coverage have been produced for northern Canada and the Canadian Arctic which are typically very difficult to access. Multi and hyperspectral airborne and spaceborne sensors are widely used for geological mapping as spectral characteristics are able to constrain the minerals and rocks that are present in a target region. Rock surfaces in the Canadian Arctic are altered by extensive glacial activity and freeze-thaw weathering, and form different surface roughnesses depending on rock type. …


The Development Of Peptide Analogues As Potential Fluorescent And Pet Imaging Probes., Neha Sharma Dec 2017

The Development Of Peptide Analogues As Potential Fluorescent And Pet Imaging Probes., Neha Sharma

Electronic Thesis and Dissertation Repository

Molecular imaging is a non-invasive way to diagnose disease. Molecular imaging probes consist of a targeting entity that has a high affinity for a biological target and a signaling source for external detection. Multimodality imaging combines the advantages of different imaging modalities, at the same time eliminating their shortcomings, thereby providing more accurate results. This thesis focuses on the development of novel dual PET/fluorescence imaging agents based on peptides as targeting entities.

Porphyrins are suitable for multimodality imaging applications due to their innate characteristics such as an ability to fluoresce and to coordinate metals. A gallium-protoporphyrin IX(PPIX)-ghrelin based analogue was …


Similar Ultrafast Dynamics Of Several Dissimilar Dirac And Weyl Semimetals, Christopher P. Weber, Bryan S. Berggren, Madison G. Masten, Thomas C. Ogloza, Skylar Deckoff-Jones, Julien Madéo, Michael K. L. Man, Keshav M. Dani, Lingxiao Zhao, Genfu Chen, Jinyu Liu, Zhiqiang Mao, Leslie M. Schoop, Bettina V. Lotsch, Stuart S. P. Parkin, Mazhar Ali Dec 2017

Similar Ultrafast Dynamics Of Several Dissimilar Dirac And Weyl Semimetals, Christopher P. Weber, Bryan S. Berggren, Madison G. Masten, Thomas C. Ogloza, Skylar Deckoff-Jones, Julien Madéo, Michael K. L. Man, Keshav M. Dani, Lingxiao Zhao, Genfu Chen, Jinyu Liu, Zhiqiang Mao, Leslie M. Schoop, Bettina V. Lotsch, Stuart S. P. Parkin, Mazhar Ali

Physics

Recent years have seen the rapid discovery of solids whose low-energy electrons have a massless, linear dispersion, such as Weyl, line-node, and Dirac semimetals. The remarkable optical properties predicted in these materials show their versatile potential for optoelectronic uses. However, little is known of their response in the picoseconds after absorbing a photon. Here, we measure the ultrafast dynamics of four materials that share non-trivial band structure topology but that differ chemically, structurally, and in their low-energy band structures: ZrSiS, which hosts a Dirac line node and Dirac points; TaAs and NbP, which are Weyl semimetals; and Sr1–y …


U.S. - Canadian Border Traffic Prediction, Colin Middleton Dec 2017

U.S. - Canadian Border Traffic Prediction, Colin Middleton

WWU Honors College Senior Projects

Mathematical discussion and analysis of several prediction methods which use real time data to predict traffic flow at the U.S. - Canadian Border crossings.


Hodge Theory On Transversely Symplectic Foliations, Yi Lin Dec 2017

Hodge Theory On Transversely Symplectic Foliations, Yi Lin

Department of Mathematical Sciences Faculty Publications

In this paper, we develop symplectic Hodge theory on transversely symplectic foliations. In particular, we establish the symplectic dδ-lemma for any such foliations with the (transverse) s-Lefschetz property. As transversely symplectic foliations include many geometric structures, such as contact manifolds, co-symplectic manifolds, symplectic orbifolds, and symplectic quasi-folds as special examples, our work provides a unifying treatment of symplectic Hodge theory in these geometries.

As an application, we show that on compact K-contact manifolds, the s-Lefschetz property implies a general result on the vanishing of cup products, and that the cup length of a 2n+1 dimensional compact K-contact manifold with the …