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Articles 1471 - 1500 of 2456

Full-Text Articles in Physical Sciences and Mathematics

Towards The Substrate-Bound Structure Of Streptococcus Pneumoniae Sortase A, Orion Banks Jan 2017

Towards The Substrate-Bound Structure Of Streptococcus Pneumoniae Sortase A, Orion Banks

WWU Graduate School Collection

Bacterial sortases have been widely studied for their usefulness in protein modification, however, the variable substrate specificity and activity between homologs of these enzymes is not yet fully characterized. To attempt to further understand sorting signal recognition, we have made advances towards a substrate bound structure of Streptococcus pneumoniae sortase A (SrtApneu). This enzyme displays a wide tolerance for alternate amino acids within the canonical LPXTG sorting motif. Our strategy involves a non-cleavable peptide analog that can be docked into the active site, allowing for elucidation of a structure displaying the key contacts that allow the enzyme to …

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Clustering Of Epigenetic Methylation And Oxidative Damage: Effects On Duplex Dna Solution Structure, Thermodynamic Stability And Local Dynamics, David R. Gruber Jan 2017

Clustering Of Epigenetic Methylation And Oxidative Damage: Effects On Duplex Dna Solution Structure, Thermodynamic Stability And Local Dynamics, David R. Gruber

WWU Graduate School Collection

All known living organisms use DNA to store genetic templates used for development, proper function and reproduction. The structural integrity of DNA is therefore of extreme importance and cellular machinery continuously regulates our DNA either through addition of covalent molecules to regulate the transcription of genes or the removal of DNA lesions propagating from the exposure to reactive molecules. One of the most common DNA lesions, 8-oxoguanine (8OG), is a prominent, pro-mutagenic DNA adduct present at a baseline level from consistent generation of reactive oxygen species through oxidative metabolism or at greater concentrations through exposure to ionizing radiation and …

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Probing The Secondary Coordination Sphere Of Zn(Ii) And Fe(Ii) Pyridinediimine (Pdi) Complexes, Mayra Delgado Jan 2017

Probing The Secondary Coordination Sphere Of Zn(Ii) And Fe(Ii) Pyridinediimine (Pdi) Complexes, Mayra Delgado

WWU Graduate School Collection

The transformation of many small, abundant molecules is necessary both in a biological setting and in the chemical industry. In Nature, the activation of small molecules is promoted by metalloenzymes. However, many of these chemical transformations are thermodynamically demanding and consist of multi-electron redox processes. Understanding the secondary coordination sphere has played an integral role in determining the catalytic activity and selectivity of such transformations and has led to the development of bioinspired catalysts in order to mimic the native active site of the metalloenzyme. Due to its extensive modularity, the utilization of the pyridinediimine (PDI) metal complexes was targeted …

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Structural Characterization Of Factor Viii C2 Domain Activated Platelet Membrane Binding, Serena W. Wo Jan 2017

Structural Characterization Of Factor Viii C2 Domain Activated Platelet Membrane Binding, Serena W. Wo

WWU Graduate School Collection

Hemophilia A is an X-linked blood disorder that results in the inability to form proper blood clots and may also cause spontaneous bleeding in the joints or muscles. This disorder is caused by mutations in the F8 gene that attenuate or abolish the activity of its protein product, factor VIII. Blood coagulation factor VIII (fVIII) is a glycoprotein that serves as a cofactor for the serine protease factor IXa on the surface of activated platelets to form the intrinsic tenase complex, which activates factor X during hemostasis to enable blood clot formation. Previous studies have shown that the C-terminal (C2) …

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Structural And Functional Characterization Of The F-Actin Binding Headpiece Domain Of Plant Villin 4, Heather Miears Jan 2017

Structural And Functional Characterization Of The F-Actin Binding Headpiece Domain Of Plant Villin 4, Heather Miears

WWU Graduate School Collection

The villin family of proteins are filamentous actin (F-actin) regulators, which play key roles in cytoskeleton organization regulation in eukaryotes. Recently discovered villin 4, from A. thaliana has been shown to bundle F-actin in root hairs. However, previous work found that mutations to villin 4 result in shorter and sparser root hairs which lead to a weaker capacity for water absorption by A. thaliana. It is previously known that many members of the vertebrate villin protein family contain a highly conserved F-actin binding site within the C-terminal headpiece domain. In order to investigate the headpiece of villin 4, we …

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Initiation And Evolution Of Subduction: T-T-D History Of The Easton Metamorphic Suite, Northwest Washington State, Jeremy Cordova Jan 2017

Initiation And Evolution Of Subduction: T-T-D History Of The Easton Metamorphic Suite, Northwest Washington State, Jeremy Cordova

WWU Graduate School Collection

In the Northwest Cascades, results from previous workers show the Easton Metamorphic Suite contains an inverted metamorphic sequence with ultramafic rocks underlain by amphibolite and high-temperature blueschist that are juxtaposed above high-pressure low-temperature Shuksan Greenschist and Darrington Phyllite. In this study, amphibole and white mica 40Ar/39Ar geochronology is combined with cation exchange thermometry to constrain the temperature-time-deformation history of the suite. Amphibolite facies fabrics record two deformation events at 10 kbar. The oldest fabric formed at ~760 ̊C prior to 167.4 Ma (2σ). A second fabric formed at ~590 ̊C prior to 164.4 Ma. Na-amphibole schist associated …

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Elk Abundance Estimation And Road Ecology In Whatcom And Skagit Counties, Washington, Nathan C. Rice Jan 2017

Elk Abundance Estimation And Road Ecology In Whatcom And Skagit Counties, Washington, Nathan C. Rice

WWU Graduate School Collection

Chapter 1 – Elk abundance estimation using genetic mark-recapture in the South Fork Nooksack Valley, Whatcom County Washington. Non-invasive genetic mark-recapture is an increasingly useful method for estimating the abundance of elusive wildlife. This method was used to estimate the size of an elk population (Cervus canadensis) in the South Fork Nooksack River valley in northwestern Washington where dense forest cover can hamper aerial surveys. We genotyped 250 elk fecal DNA samples that were collected in a single sampling session. Only 103 samples amplified sufficiently after one PCR for genotype matching, which resulted in 49 unique genotypes. Program Capwire estimated …

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Sediment Budget Of The Middle Reach Skagit River, Washington 1937-2015 Reveals Decadal Variations In Sediment Export And Storage, Amelia Deuell Rothleutner Jan 2017

Sediment Budget Of The Middle Reach Skagit River, Washington 1937-2015 Reveals Decadal Variations In Sediment Export And Storage, Amelia Deuell Rothleutner

WWU Graduate School Collection

Evaluation of historical meandering since 1937 shows that the active floodplain of the middle reach Skagit River between Rockport and Sedro-Woolley, Washington, has periodically been a significant source of sediment to the lower Skagit River and delta. In response to recent findings that the Sauk-Suiattle on average only supplies approximately 30% of the sediment load observed at Mount Vernon, I examined the geomorphic change and potential sediment production of the middle reach to test whether it is a significant source to the lower river. I tested the hypothesis that the 20-mile (32-km) middle reach has been a net source of …

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Sea Level Change In The Gulf Islands National Park Reserve, Southern British Columbia: Implications For The Interpretation Of Nearshore Archaeological Features, Glenda J. Wyatt Dec 2016

Sea Level Change In The Gulf Islands National Park Reserve, Southern British Columbia: Implications For The Interpretation Of Nearshore Archaeological Features, Glenda J. Wyatt

Salish Sea Ecosystem Conference

Sea level along the B.C. coastline has changed dramatically over the past 10,000 years due to isostatic rebound following deglaciation from the Fra ser Glaciation (Clague & James, 2002). In the future, sea levels globally are also predicted to rise according to the Intergovernmental Panel on Climate Change (IPCC) (2014), due to climate change. Lemmen et al. (2008), suggest that in the near future some B.C. coastal communities will have to deal with changes in shorelines due to rising sea levels, and hence erosional patterns, modifications to ecosystems and habitats, and potentially an altered marine food supply. This thesis examines …

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Pacific Great Blue Heron Population Monitoring On Vancouver Island And The Surrounding Gulf Islands, Trudy A. Chatwin, Travis Heckford Dec 2016

Pacific Great Blue Heron Population Monitoring On Vancouver Island And The Surrounding Gulf Islands, Trudy A. Chatwin, Travis Heckford

Salish Sea Ecosystem Conference

The Pacific or Great Blue Heron fannini subspecies winters and breeds on Vancouver Island in locations within 5 km of the marine shoreline. Its visibility and close connection to the Salish Sea make it an important flagship species. Due to population concerns and threats associated with urban development, the Province of BC has coordinated monitoring of Great Blue Heron colonies on Vancouver Island and the adjacent Gulf Islands from 1997 through 2015. Starting in 2005, I trained volunteer stewards and technicians to use a standardized methodology to locate and assess heron colonies, count active nests, determine nest success and follow …

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Stacked Antiaromatic Porphyrins, Ryo Nozawa, Hiroko Tanaka, Won-Young Cha, Yongseok Hong, Ichiro Hisaki, Soji Shimizu, Ji-Young Shin, Tim Kowalczyk, Stephan Irle, Dongho Kim, Hiroshi Shinokubo Nov 2016

Stacked Antiaromatic Porphyrins, Ryo Nozawa, Hiroko Tanaka, Won-Young Cha, Yongseok Hong, Ichiro Hisaki, Soji Shimizu, Ji-Young Shin, Tim Kowalczyk, Stephan Irle, Dongho Kim, Hiroshi Shinokubo

Chemistry Faculty and Staff Publications

Aromaticity is a key concept in organic chemistry. Even though this concept has already been theoretically extrapolated to three dimensions, it usually still remains restricted to planar molecules in organic chemistry textbooks. Stacking of antiaromatic π-systems has been proposed to induce three-dimensional aromaticity as a result of strong frontier orbital interactions. However, experimental evidence to support this prediction still remains elusive so far. Here we report that close stacking of antiaromatic porphyrins diminishes their inherent antiaromaticity in the solid state as well as in solution. The antiaromatic stacking furthermore allows a delocalization of the π-electrons, which enhances the two-photon absorption …

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Executive Summary: Western Libraries Beta Website Usability, Rebecca M. Marrall, Nora K. Burmeister, Jon Dillon Nov 2016

Executive Summary: Western Libraries Beta Website Usability, Rebecca M. Marrall, Nora K. Burmeister, Jon Dillon

Usability & Design Working Group Documents

This brief report provides an overview of the Fall Quarter 2016 usability sessions on the Western Libraries beta website. The purpose of this report is to inform Libraries and Learning Commons personnel of our next steps with the beta website. There were 36 participants over the course of five two hour sessions.

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Most Observations Of Our Nearest Neighbor: Flares On Proxima Centauri, James R. A. Davenport, David M. Kipping, Dimitar Sasselov, Jaymie M. Matthews, Chris Cameron Oct 2016

Most Observations Of Our Nearest Neighbor: Flares On Proxima Centauri, James R. A. Davenport, David M. Kipping, Dimitar Sasselov, Jaymie M. Matthews, Chris Cameron

Physics & Astronomy

We present a study of white-light flares from the active M5.5 dwarf Proxima Centauri using the Canadian microsatellite Microvariability and Oscillations of STars. Using 37.6 days of monitoring data from 2014 to 2015, we have detected 66 individual flare events, the largest number of white-light flares observed to date on Proxima Cen. Flare energies in our sample range from 1029 to 1031.5erg. The flare rate is lower than that of other classic flare stars of a similar spectral type, such as UV Ceti, which may indicate Proxima Cen had a higher flare rate in its youth. …

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The Planet, 2016, Fall, Jesse Nichols, Huxley College Of The Environment, Western Washington University Oct 2016

The Planet, 2016, Fall, Jesse Nichols, Huxley College Of The Environment, Western Washington University

The Planet

No abstract provided.

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The Kepler Catalog Of Stellar Flares, James R. A. Davenport Sep 2016

The Kepler Catalog Of Stellar Flares, James R. A. Davenport

Physics & Astronomy

A homogeneous search for stellar flares has been performed using every available Kepler light curve. An iterative light curve de-trending approach was used to filter out both astrophysical and systematic variability to detect flares. The flare recovery completeness has also been computed throughout each light curve using artificial flare injection tests, and the tools for this work have been made publicly available. The final sample contains 851,168 candidate flare events recovered above the 68% completeness threshold, which were detected from 4041 stars, or 1.9% of the stars in the Kepler database. The average flare energy detected is ~1035 erg. …

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The Time-Domain Spectroscopic Survey: Understanding The Optically Variable Sky With Sequels In Sdss-Iii, John J. Ruan, Scott F. Anderson, Paul J. Green, Eric Morganson, Michael Eracleous, Adam D. Myers, Carles Badenes, Matthew A. Bershady, William N. Brandt, Kenneth C. Chambers, James R. A. Davenport, Kyle S. Dawson, Heather Flewelling, Timothy M. Heckman, Jedidah C. Isler, Nick Kaiser, Jean-Paul Kneib, Chelsea L. Macleod, Isabelle Paris, Nicholas P. Ross, Jessie C. Runnoe, Edward F. Schlafly, Sarah J. Schmidt, Donald P. Schneider, Axel D. Schwope, Yue Shen, Keivan G. Stassum, Paula Szkody, Christoper Z. Waters, Donald G. York Jul 2016

The Time-Domain Spectroscopic Survey: Understanding The Optically Variable Sky With Sequels In Sdss-Iii, John J. Ruan, Scott F. Anderson, Paul J. Green, Eric Morganson, Michael Eracleous, Adam D. Myers, Carles Badenes, Matthew A. Bershady, William N. Brandt, Kenneth C. Chambers, James R. A. Davenport, Kyle S. Dawson, Heather Flewelling, Timothy M. Heckman, Jedidah C. Isler, Nick Kaiser, Jean-Paul Kneib, Chelsea L. Macleod, Isabelle Paris, Nicholas P. Ross, Jessie C. Runnoe, Edward F. Schlafly, Sarah J. Schmidt, Donald P. Schneider, Axel D. Schwope, Yue Shen, Keivan G. Stassum, Paula Szkody, Christoper Z. Waters, Donald G. York

Physics & Astronomy

The Time-Domain Spectroscopic Survey (TDSS) is an SDSS-IV eBOSS subproject primarily aimed at obtaining identification spectra of ~220,000 optically variable objects systematically selected from SDSS/Pan-STARRS1 multi-epoch imaging. We present a preview of the science enabled by TDSS, based on TDSS spectra taken over ~320 deg2 of sky as part of the SEQUELS survey in SDSS-III, which is in part a pilot survey for eBOSS in SDSS-IV. Using the 15,746 TDSS-selected single-epoch spectra of photometrically variable objects in SEQUELS, we determine the demographics of our variability-selected sample and investigate the unique spectral characteristics inherent in samples selected by variability. We …

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Using Clinopyroxene Mineral Chemistry To Decipher Magma Composition Changes Over The 13 Million Year History Of The Izu-Bonin Volcanic Arc, Erin Benson Jun 2016

Using Clinopyroxene Mineral Chemistry To Decipher Magma Composition Changes Over The 13 Million Year History Of The Izu-Bonin Volcanic Arc, Erin Benson

Geology Graduate and Undergraduate Student Scholarship

International Ocean Discovery Program Expedition 350 recovered 2000 meters of volcanic rock core in spring, 2014 at the Izu-Bonin-Mariana Rear Arc. The core has been divided into seven lithostratigraphic units, from age 0 at the top to at least 13 million years at the bottom. The major and trace element geochemistry of representative mineral grains in volcaniclastic rocks throughout the core from top to bottom were analyzed and used as a proxy for interpreting magma compositional changes through time. The clinopyroxene from all units and the glass from Unit I were analyzed for major elements (by SEM and electron microprobe) …

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Surface Slip During Large Owens Valley Fault Earthquakes, Elizabeth K. Haddon, Colin B. Amos, O. Zielke, A. S. Jayko, R. Bürgmann Jun 2016

Surface Slip During Large Owens Valley Fault Earthquakes, Elizabeth K. Haddon, Colin B. Amos, O. Zielke, A. S. Jayko, R. Bürgmann

Geology Faculty Publications

The 1872 Owens Valley earthquake is the third largest known historical earthquake in California. Relatively sparse field data and a complex rupture trace, however, inhibited attempts to fully resolve the slip distribution and reconcile the total moment release. We present a new, comprehensive record of surface slip based on lidar and field investigation, documenting 162 new measurements of laterally and vertically displaced landforms for 1872 and prehistoric Owens Valley earthquakes. Our lidar analysis uses a newly developed analytical tool to measure fault slip based on cross‐correlation of sublinear topographic features and to produce a uniquely shaped probability density function (PDF) …

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Detecting Binaries Via Cross Correlation Function Subtraction, Jessica Reyna May 2016

Detecting Binaries Via Cross Correlation Function Subtraction, Jessica Reyna

Scholars Week

No abstract provided.

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Membership Survey Of The Alpha Persei Open Stellar Cluster, Graham Roberts May 2016

Membership Survey Of The Alpha Persei Open Stellar Cluster, Graham Roberts

Scholars Week

Alpha Persei is a young stellar open cluster in our Galaxy. Stellar open clusters are groups of stars that formed at the same time from a single cloud in the interstellar medium. Cluster’s well defined ages allow astronomers to calibrate stellar evolution models with measurements of constituent members, and track the history of star formation in the Milky Way. Alpha Persei is relatively young, on the scale of around 100 million years old (Shiekhi et al. 2016). Alpha Per provides a key laboratory for studying the properties, such as mass, radii, temperature, etc. of young stars. We have yet to …

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Using Clinopyroxene Mineral Chemistry To Decipher Magma Composition Changes Over 13 Million Years In The Izu-Bonin Volcanic Arc, Erin Benson, Brian Rusk, Ricardo Escobar, Luan Heywood May 2016

Using Clinopyroxene Mineral Chemistry To Decipher Magma Composition Changes Over 13 Million Years In The Izu-Bonin Volcanic Arc, Erin Benson, Brian Rusk, Ricardo Escobar, Luan Heywood

Scholars Week

International Ocean Drilling Program (IODP) Expedition 350 drilled into the relatively unexplored rear arc of the Izu-Bonin-Mariana system (see map). It recovered 2000 meters of volcanic rock core in the spring of 2014. The core has been divided into seven lithostratigraphic units, from age 0 at the top to at least 13 million years at the bottom. I analyzed the major and trace element geochemistry of representative clinopyroxene and glass (in Unit I) and just clinopyroxene (in all other units) in volcaniclastic rocks throughout the core from top to bottom and used them as a proxy for interpreting magma compositional …

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Intramolecular Reductive Heck Approach To Guaipyridine Alkaloids, Samantha Grosslight, Hope Spargo May 2016

Intramolecular Reductive Heck Approach To Guaipyridine Alkaloids, Samantha Grosslight, Hope Spargo

Scholars Week

The guaipyridine alkaloids are a family of compounds that all share an unusual carbon structure, whose source plants have been used as a traditional medicine in Southeast Asia. Members of the guaipyridine family include cananodine and the rupestines. Cananodine has been isolated from the fruits of the Canaga odorata in Indonesia, Malaysia and the Philippines. Cananodine has been used of decades as a traditional medicine for the treatment of malaria, infections and fever. Studies of cananodine’s biological activity have reveled activity against Hep G2 and Hep 2,2,15 human hepatocarcinoma cell lines, the most common types of liver cancer. Due to …

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Evaluating Nucleophile And Substrate Specificities Of Sortase A Homologs For Orthogonal Reactivity, Nicholas Horvath, Jesse Prelesnik May 2016

Evaluating Nucleophile And Substrate Specificities Of Sortase A Homologs For Orthogonal Reactivity, Nicholas Horvath, Jesse Prelesnik

Scholars Week

Enzymes have become an attractive option for protein modification chemistry due to the remarkable site-specificity they afford. Of particular interest is sortase A from taphylococcus aureus (SrtAaur), which has garnered attention for its ability to install a variety of non-natural modifications to a conserved oligopeptide substrate. In addition to SrtAaur it has become apparent that sortase A homologs exist in other bacterial strains, each of which is potentially a novel catalyst for protein engineering. Previous work has demonstrated that eight representative sortase A homologs exhibit unique specificities for synthetic peptide substrates, capable of identifying characteristic combinations of amino acids in …

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Gold Catalyzed Lactonization Of Epoxide Esters, Carlos Enciso Lopez May 2016

Gold Catalyzed Lactonization Of Epoxide Esters, Carlos Enciso Lopez

Scholars Week

Lactones are cyclic esters of varying ring size that occur naturally in organic compounds. Organic structures such as these have various useful biological activities applicable to antibacterial drugs, potential anticancer drugs, and participants of metabolic processes. Gold catalysts Au(I) and Au(III) are shown in our experiments to be effective in inducing intramolecular lactonization of epoxide esters to form desired lactone products. In our experiments gold catalysts coordinated with epoxides to develop a positive charge on the carbon nearest to the carbonyl. The result is an intramolecular lactonization of the ester via nucleophilic attack of the carbonyl oxygen onto the positive …

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The Influence Of Ectomycorrhizal Colonization On American Chestnut Trees (Castanea Dentata) With Regard To Growth, Fecundity, And Susceptibility To Chestnut Blight (Cryphonectria Parasitica)., John Adamson May 2016

The Influence Of Ectomycorrhizal Colonization On American Chestnut Trees (Castanea Dentata) With Regard To Growth, Fecundity, And Susceptibility To Chestnut Blight (Cryphonectria Parasitica)., John Adamson

Scholars Week

Ectomycorrhizal fungi (ECM) contribute to the primary productivity and biogeochemical cycling of forest ecosystems. These fungi create symbiotic relationships with plants roots, which allow for the transfer of water and nutrients to the plant and photosynthates to the fungal symbiont. The provision of water and soil nutrients are important for the establishment of seedlings in forest restoration projects. The objective of this study was to understand the relationship between ECM root colonization and tree health in disturbed soils on a reclaimed strip mine. Data were collected from 117, six-year-old trees to assess tree growth, fecundity and the tree’s susceptibility to …

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Kinetic And Equilibrium Sorption Modeling Of Arsenite And Arsenate Onto Lake Whatcom Sediments And Activated Carbon., Holly Young, Fischer L. Young, Henry T. Cade May 2016

Kinetic And Equilibrium Sorption Modeling Of Arsenite And Arsenate Onto Lake Whatcom Sediments And Activated Carbon., Holly Young, Fischer L. Young, Henry T. Cade

Scholars Week

Arsenic from anthropogenic sources and geological weathering is a contaminant of concern in sediment environments of Washington State. Legacy contamination can be attributed to extensive application of lead-arsenate pesticides and industrial smelting processes. Arsenic contamination of sediment provides an exposure pathway into groundwater and can potentially contaminate drinking water. Metal bioavailability of contaminated sediment is greatly influenced by the presence of acid volatile sulfides and organic carbon. Activated carbon (AC) has been shown to be an effective in-situ treatment for decreasing bioavailability of organic contaminants in sediment. Less is known about the applicability of AC to decrease metal mobility in …

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Solving The Molecular Structure Of Hybrid Human-Porcine Factor Viii Through X-Ray Crystallization, Mikko Sayre, Amanda Weis, Brenna Park-Egan May 2016

Solving The Molecular Structure Of Hybrid Human-Porcine Factor Viii Through X-Ray Crystallization, Mikko Sayre, Amanda Weis, Brenna Park-Egan

Scholars Week

Factor VIII (fVIII) is a protein that is involved in the coagulation cascade, a collection of reactions that is activated by injury and leads to the formation of blood clots. Deficiencies in fVIII lead to the bleeding disorder hemophilia A, a condition that occurs in 1 in 5000 births. The current treatment for hemophilia A is inefficient and costly; however, there is potential through the use of recombinant hybrid human-porcine fVIII. Hybrid fVIII shows up to 12-fold higher coagulant activity than human fVIII, and can retain its activity even in the presence of inhibitory antibodies. The primary objective of our …

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Surface-Enhanced Raman Scattering Optical Fibers As Chemical Sensors, Deanna Myers, Luke Degraaff May 2016

Surface-Enhanced Raman Scattering Optical Fibers As Chemical Sensors, Deanna Myers, Luke Degraaff

Scholars Week

There is a great need to be able to measure chemical environments at both the cellular and sub- cellular levels in real time because chemical irregularities in these environments are indicative of many disease states. In this project, a surface-enhanced Raman scattering (SERS) based optical fiber sensor is designed to monitor pH in real time. SERS spectra of reporter molecules adsorbed on the fiber are used to deliver information on the chemical composition of the environment.

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Examining The Relationships Between Colour, Teff, And [M/H] For Apogee K And M Dwarfs, Sarah J. Schmidt, Erika L. Wagoner, Jennifer A. Johnson, James R. A. Davenport, Keivan G. Stassun, Diogo Souto, Jian Ge May 2016

Examining The Relationships Between Colour, Teff, And [M/H] For Apogee K And M Dwarfs, Sarah J. Schmidt, Erika L. Wagoner, Jennifer A. Johnson, James R. A. Davenport, Keivan G. Stassun, Diogo Souto, Jian Ge

Physics & Astronomy

We present the effective temperatures (Teff), metallicities, and colours in Sloan Digital Sky Survey (SDSS), Two Micron All Sky Survey, and Wide-field Infrared Survey Explorer filters, of a sample of 3834 late-K and early-M dwarfs selected from the SDSS Apache Point Observatory Galactic Evolution Experiment (APOGEE) spectroscopic survey ASPCAP (APOGEE Stellar Parameters and Chemical Abundances Pipeline) catalogue. We confirm that ASPCAP Teff values between 3550 < Teff < 4200 K are accurate to ∼100 K compared to interferometric Teff values. In that same Teff range, ASPCAP metallicities are accurate to 0.18 dex between −1.0 <[M/H]g − r is not a good indicator of metallicity for near-solar metallicity early-M dwarfs. We confirm that J − KS colour is strongly dependent on metallicity, and find that W1 − W2 colour is a promising …

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Predicting College Students’ Online Help-Seeking Behavior: The Effect Of Learning Proficiency, Interest, Prior Knowledge, Epistemological Belief, And Problem Difficulty, Qiang Hao, Brad Barnes, Robert C. Branch, Ewan Wright Apr 2016

Predicting College Students’ Online Help-Seeking Behavior: The Effect Of Learning Proficiency, Interest, Prior Knowledge, Epistemological Belief, And Problem Difficulty, Qiang Hao, Brad Barnes, Robert C. Branch, Ewan Wright

Computer Science Faculty and Staff Publications

Help seeking has been identified as a learning strategy manifesting capacities for self-regulated learning (Aleven, et al., 2003). Nevertheless, there is evidence that students often encounter barriers in help seeking in classroom settings. This may involve difficulties in identifying helpers or hesitation in approaching helpers due to anxiety or a lack of self-confidence (Ryan & Shin, 2011). Aided by web technology, students may not need to face such barriers when seeking help. Moreover, communicating with experts online or utilizing search engines makes abundant relevant information accessible, and is arguably less intimidating than face-to-face interactions. As a result, students seeking online …

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