Digital Commons Network^™

Stromatolites And Miss—Differences Between Relatives, N. Noffke, S. M. Awramik

OES Faculty Publications

Benthic microorganisms form highly organized communities called “biofilms.” A biofilm consists of the individual cells plus their extracellular polymeric substances (EPS). In marine and non-marine environments, benthic microbial communities interact with the physical sediment dynamics and other factors in the environment in order to survive. This interaction can produce distinctive sedimentary structures called microbialites. Binding, biostabilization, baffling, and trapping of sediment particles by microorganisms result in the formation of microbially induced sedimentary structures (MISS); however, if carbonate precipitation occurs in EPS, and these processes happen in a repetitive manner, a multilayered build-up can form—stromatolites. Stromatolites and MISS are first found …

Microbially Induced Sedimentary Structures Recording An Ancient Ecosystem In The Ca. 3.48 Billion-Year-Old Dresser Formation, Pilbara, Western Australia, Nora Noffke, Daniel Christian, David Wacey, Robert M. Hazen

OES Faculty Publications

Microbially induced sedimentary structures (MISS) result from the response of microbial mats to physical sediment dynamics. MISS are cosmopolitan and found in many modern environments, including shelves, tidal flats, lagoons, riverine shores, lakes, interdune areas, and sabkhas. The structures record highly diverse communities of microbial mats and have been reported from numerous intervals in the geological record up to 3.2 billion years (Ga) old. This contribution describes a suite of MISS from some of the oldest well-preserved sedimentary rocks in the geological record, the early Archean (ca. 3.48 Ga) Dresser Formation, Western Australia. Outcrop mapping at the meter to …

Distributions Of Particulate Heme B In The Atlantic And Southern Oceans- Implications For Electron Transport In Phytoplankton, Martha Gledhill, Eric P. Achterberg, David J. Honey, Maria C. Nielsdottir, Micha J.A. Rijkenberg

OES Faculty Publications

Concentrations of heme b, the iron-containing component of b-type hemoproteins, ranged from b concentrations were enhanced in the photic zone and decreased with depth. Heme b concentrations correlated positively with chlorophyll a (chl a) in the TNA (r=0.41, pb did not correlate with chl a in the IB or SS. In the IB and SS, stations with high-chlorophyll and low-nutrient (Fe and/or Si) concentrations exhibited low heme bconcentrations relative to particulate organic carbon (< 0.1 μmolmol^-1, and high chl a:heme b ratios (> 500). High chl a:heme b ratios resulted from relative decreases in …

Synthesis And Characterization Of Thermally Stable Camphor-Based Polyimide--Clay Nanocomposites, Murat Yi̇ği̇t, Turgay Seçki̇n, Beyhan Yi̇ği̇t, Süleyman Köytepe

Turkish Journal of Chemistry

A new monomer was prepared from (1R,3S)-(+)-camphoric acid. Novel polyimide and polyimide--clay hybrid composites were developed from one-pot condensation reactions of this monomer and pyromellitic dianhyride. Polyimide-montmorillonite nanocomposites were prepared from solution of polyimide and with different weight percentages (1, 5, 10 wt %) of organo-modified montmorillonite (OM-MMT) using N-methyl-2-pyrrolidone (NMP) as aprotic solvent. The reactive organoclay was formed by using hexadecylpyridinium chloride as a swelling agent for silicate layers of montmorillonite. The polyimide--clay composites films (PI--MMT) were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD). All composites were subjected to differential scanning calorimetry …

Synthesis And Cytotoxic Activity Of Some 2-(2,3-Dioxo-2,3-Dihydro-1h-Indol-1-Yl)Acetamide Derivatives, Özlem Akgül, Ayşe Hande Tari̇koğullari, Fadi̇me Aydin Köse, Petek Ballar Kirmizibayrak, Mehmet Varol Pabuççuoğlu

Turkish Journal of Chemistry

Isatin, 1H-indoline-2,3-dione, an endogenous compound, is also a synthetically versatile molecule that possesses a diversity of biological activities including anticonvulsant, antibacterial, antifungal, antiviral, anticancer, and cytotoxic properties. Based on the promising cytotoxic activity studies on N-substituted isatin derivatives, a series of 18 derivatives of 2-(2,3-dioxo-2,3-dihydro- 1H-indol-1-yl)-N-phenylacetamide were designed, synthesized, and characterized according to their analytical and spectral data. All of the compounds were evaluated for their cytotoxic activity against MCF7, A549, HeLa, and HEK293 cell lines by real time cell analyzer. Etoposide was used as a standard compound. Briefly, ortho substitutions gave better results compared to meta and para substitutions …

A One-Pot Strategy For Regioselective Synthesis Of 6-Aryl-3-Oxo-2,3-Dihydropyridazine-4-Carbohydrazides, Mehdi Rimaz, Hossein Mousavi

Turkish Journal of Chemistry

A simple and efficient method for the synthesis of 6-aryl-3-oxo-2,3-dihydropyridazine-4-carbohydrazide derivatives was developed. The synthesis was achieved via one-pot multicomponent reaction of arylglyoxals, dialkylmalonates, and hydrazine hydrate in pyridine at room temperature. This procedure features high regioselectivity, generally good to excellent yields, the use of easily available starting materials, and operational simplicity. This chemistry provides an efficient and promising synthetic strategy for diversity-oriented construction of the 6-arylpyridazinone skeleton.

Antimicrobial Activity And Chemical Composition Of The Essential Oils Of Mosses (Hylocomium Splendens (Hedw.) Schimp. And Leucodon Sciuroides (Hedw.) Schwägr.) Growing In Turkey, Tayyi̇be Beyza Cansu, Büşra Yayli, Turan Özdemi̇r, Nevzat Batan, Şengül Alpay Karaoğlu, Nuretti̇n Yayli

Turkish Journal of Chemistry

In the present work, the volatiles of mosses [Hylocomium splendens (Hedw.) Schimp. (Hylocomiaceae) and Leucodon sciuroides (Hedw.) Schwägr. (Leucodontaceae)] have been investigated by GC-FID and GC/MS. Fifty-eight compounds in the oil of H. splendens, representing 75.4%, and 41 compounds in the oil of L. sciuroides, representing 87.6%, were identified. The major components were found to be \beta-pinene (11.6%) and \alpha-pinene (8.9%) in the oil of H. splendens, and nonanal (26.8%) and heptanal (13.7%) in the oil of L. sciuroides. The essential oil of H. splendens was rich in monoterpenes (30.8%), and aldehydes (49.9%) were the major constituents in the oil …

Potentiometric Determination Of Some Food Additives And Their Binding To A Polycationic Species Using Polyion Sensors, Nedi̇me Dürüst, Ali̇ Kayansalan

Turkish Journal of Chemistry

Polycation-sensitive membrane electrodes based on dinonylnaphthalene sulfonate (DNNS) were examined for the determination of some polyanions, namely xanthan (Xanth), alginate (Alg), carboxymethyl cellulose (CMC), and carrageenan (Carr). The potentiometric titrations of polyanionic analytes yielded sharp end points and correlative stoichiometries. After the determinations were successfully performed in saline, these polyanions were also determined in some food products consumed in Bolu (Turkey). In addition, the titration data were used to estimate the interactions between titrant and polyanionic analytes. The equilibrium constants, K_{eq}, and the number of titrant binding sites (n) per mole of analyte polyanion were calculated using Scatchard plots. The …

Application Of Experimental Design On Determination Of Aluminum Content In Saline Samples By Adsorptive Cathodic Stripping Voltammetry, Si̇nan Yilmaz, Betül Öztürk, Durmuş Özdemi̇r, Ahmet Emi̇n Eroğlu, Fatma Ni̇l Ertaş

Turkish Journal of Chemistry

Adsorptive cathodic stripping voltammetric determination of aluminum at ng mL^{-1} levels in salt samples based on the metal complexation with Calcon (1-(2-hydroxynaphthylazo)-2 naphthol-4-sulfonic acid) and the subsequent adsorptive deposition onto a hanging mercury drop electrode was studied. Central composite design was used as a design method. Several chemical and instrumental parameters (pH, ligand concentration, deposition time, deposition potential, and complexing time) were involved in the experimental design. Analytical parameters such as repeatability, linearity, and accuracy were also investigated and the detection limit was found as 0.32 ng mL^{-1}.

Study On Crystal Transformation Process Of Magnesium Carbonate Hydrate Based On Salt Lake Magnesium Resource Utilization, Juan Du, Zhen Chen, Yulong Wu, Mingde Yang, Jie Dang, Jianjun Yuan

Turkish Journal of Chemistry

The crystal transformation process of magnesium carbonate hydrate by the reaction of magnesium sulfate (MgSO_4) with ammonium carbonate [(NH_4)_2CO_3] was investigated. MgSO_4 is one of the main magnesium resources of the Lop Nur salt lake in the Xinjiang Autonomous Region of China. Magnesium carbonate hydrates with different chemical compositions were prepared. The transformation process of the 2 crystals, MgSO_4 and (NH_4)_2CO_3, was analyzed by Raman spectroscopy, and the associated changes in crystal morphology were observed by scanning electron microscopy. The needle-like MgCO_3 \cdot 3H_2O transformed into sheet-like 4MgCO_3 \cdot Mg(OH)_2 \cdot 4H_2O when the temperature was increased from 323 K …

Development And Deployment Of A Point-Source Digital Inline Holographic Microscope For The Study Of Plankton And Particles To A Depth Of 6000 M, Alexander B. Bochdansky, Manfred H. Jericho, Gerhard J. Herndl

OES Faculty Publications

Bochdansky, A. B., Jericho, M. H., & Herndl, G. J. (2013). Development and deployment of a point-source digital inline holographic microscope for the study of plankton and particles to a depth of 6000 m. Limnology and Oceanography: Methods, 11, 28-40. doi: 10.4319/lom.2013.11.28

Barriers To Implementation Of Rti At The Secondary Level, Nancy Jane Holsapple

All-Inclusive List of Electronic Theses and Dissertations

The purpose of the study was to determine if there are differences among building administrators, guidance counselors, and specialEducation directors on a perceived level of implementation of Response to Intervention (RTI) at the secondary level. The study also examined whether or not RTI serves as a predictor of students identified in specialEducation. This study did not find a significant difference between perceptions of Indiana high school counselors, Indiana high school administrators and Indiana specialEducation directors. The study also revealed the six indicators of RTI do not serve as predictors for students who are identified in specialEducation. Of the three groups …

Diatom Proteomics Reveals Unique Acclimation Strategies To Mitigate Fe Limitation, Brook L. Nunn, Jessica F. Faux, Anna A. Hippman, Maria T. Maldonado, H. Rodger Harvey, David R. Goodlett, Philip W. Boyd, Robert F. Strzepek

OES Faculty Publications

Phytoplankton growth rates are limited by the supply of iron (Fe) in approximately one third of the open ocean, with major implications for carbon dioxide sequestration and carbon (C) biogeochemistry. To date, understanding how alteration of Fe supply changes phytoplankton physiology has focused on traditional metrics such as growth rate, elemental composition, and biophysical measurements such as photosynthetic competence (Fv/Fm). Researchers have subsequently employed transcriptomics to probe relationships between changes in Fe supply and phytoplankton physiology. Recently, studies have investigated longer-term (i.e. following acclimation) responses of phytoplankton to various Fe conditions. In the present study, the coastal diatom, Thalassiosira pseudonana, …

Large-Scale Cloudscapes Using Noise, Mario Rosa

Theses

Clouds have been of particular interest in computer graphics due to the challenge they present. Clouds are considered fuzzy objects, and need specialized algorithms to model and render realistically. Many techniques exist to model and render clouds that have had much success. This research will take existing techniques in cloud modeling and rendering and create a new technique combining those with noise. The idea is that noise can be used to model large-scale repeatable 3D cloudscapes and to be able to model such cloudscapes much more quickly than current techniques. This would be beneficial to developers of virtual universes that …

Effect Of Laser Ablation Depth In Otolith Life History Scans, Renée R. Hoover, Cynthia M. Jones

OES Faculty Publications

Life history scans of fish otoliths are bringing new insight into the structure, connectivity, and movement of fish populations. Data obtained from such scans, however, possess in-herent limitations that have not yet been fully addressed or understood. For example, several investigators have noted delays in otolith elemental uptake that do not appear to reflect habitat exposure. We hypothesized that the 3-dimensional structure of otoliths may produce sampling artifacts in the results obtained from laser ablation scans. To test this hypothesis, we sampled sagittal otoliths from juvenile Atlantic croaker Micropogonias undulatus with laser ablation inductively coupled plasma mass spectrometry to obtain …

Special Education Teacher Retention: The Relationship Between Mentoring, Job Satisfaction And The Retention Of Special Education Teachers, Angela Horrison-Collier

College of Graduate Studies: Theses & Dissertations

The causes of the teacher shortage are complex; however, the retention of special education teachers is a significant contributor to this shortage. Some research has indicated that up to 9.3 % of special education teachers leave the field at the end of their first year of teaching and 7.4 % move to general education yearly. Therefore, school districts face a continuous cycle of recruitment, hiring, and induction. Because of the pivotal value of retention, school districts and site level education leaders must take proactive steps to reduce the retention rate. The research on teacher retention indicates factors such as salary, …

Concept Drift Datasets, Patrick Lindstrom

Doctoral

This zip file contains the datasets used in the PhD thesis:

Lindstrom, P., 2013. Handling Concept Drift in the Context of Expensive Labels. Technological University Dublin. For more information about the datasets please see the README file and the aforementioned thesis.

Not All That Glitters Is Gold: The Effect Of Attention And Blogs On The Investors' Investing Behaviors, Nan Hu, Yi Dong, Ling Liu, Lee J. Yao

Research Collection School Of Computing and Information Systems

This article investigates the relationship between a firm’s visibility in blogspaces, termed blog exposure, and the cross-sectional stock returns. We show that blog exposure is fundamentally different from the traditional media coverage, and securities with low blog exposure earn higher returns than stocks with high blog exposure. We further illustrate that such an effect is more prominent for stocks with low institutional ownership. Contrary to traditional media coverage, the return premium associated with blog exposure cannot be explained by either the illiquidity hypothesis or the investor recognition hypothesis based on the rational-agent framework. Instead, our results suggest that blog effect …

Total Lightning As An Indicator Of Convectively Induced Turbulence Threat To Aviation Interests, Ryan Rogers

Theses

The FAA recommends that aircraft avoid thunderstorms by a minimum of 20 nautical miles horizontally. When this buffer is not maintained the chance of an aircraft experiencing turbulence is increased. The presence of lightning in a convective cell gives some indication of its turbulence potential so locations of lightning flash initiations are used to highlight updraft regions where convectively induced turbulence is generated. Data from the North Alabama Lightning Mapping Array (NALMA) serves as a proxy for Geostationary Lightning Mapper (GLM) total lightning capability. GLM proxy data are used to investigate the impact of 8x8 km resolution on lightning-turbulence relationships. …

The Association Of Blood Lipid Levels With The Epigenetic Regulation Of The Cpt1a Gene, Nikita Patel

Theses

DNA methylation directly influences gene expression. Previous studies showed that diet and genetics influence blood lipid levels. However, the association between DNA methylation and lipid levels is unknown. This study demonstrates a link between epigenetic variation and fasting blood lipid levels, particularly in triglycerides and VLDL-C. Approximately 470,000 CpGs were evaluated in 995 individuals to find epigenome-wide associations between methylation and lipid levels. Two CpGs sites located within theCPT1A gene showed strong association with fasting triglyceride and VLDC-C levels. Furthermore there was an inverse relationship between methylation levels at the most significant CpG within CPT1Aand its fold expression levels. CPT1 …

Hyperspectral Remote Sensing Of Water Quality In Lake Atitlan, Guatemala, Africa Ixmucane Flores Cordova

Theses

Lake Atitlan in Guatemala is a vital source of drinking water. The deteriorating conditions of water quality in this lake threaten human and ecological health as well as the local and national economy. Given the sporadic and limited measurements available, it is impossible to determine the changing conditions of water quality. The goal of this thesis is to use Hyperion satellite images to measure water quality parameters in Lake Atitlan. For this purpose in situ measurements and satellite-derived reflectance data were analyzed to generate an algorithm that estimated Chlorophyll concentrations. This research provides for the first time a quantitative application …

Higher Order Sliding Mode Control Of Laser Pointing For Orbital Debris Mitigation, Arthur Palosz

Theses

This thesis explores the use of a space-based laser to clean up small orbital debris from near Earth space. This system's challenge is to quickly and precisely aim the laser beam at very small (<1cm) and distant (<10km) moving orbital debris in the presence of parametric uncertainties and external disturbances. A mathematical model is derived for the debris position sensors, a Fast Steering Mirror (FSM), and a telescope which are used to track the orbital debris and then point and focus the laser beam onto the orbital debris. A Kalman Filter (KF) is designed to accurately track the orbital debris and generate a command signal for the controller. A second order Super Twisting Sliding Mode Controller (2-SMC) is designed to follow the command signal generated by the KF and to overcome the parametric uncertainties and external disturbances. The performance of the system is validated with a computer simulation created in MATLAB and Simulink.

Generation Of Radio Frequency Induced Metastable Xenon As A Gain Medium For Diode Pumped Rare Gas Laser Systems, Jacqueline Marie Andreozzi

Theses

The pursuit of novel, hybrid methods of achieving lasing from the rare gases has recently been a topic of interest in the field of high energy laser systems. This investigation presents the construction and execution of an experimental setup designed to generate metastable xenon (Xe*) to determine its potential to perform as a high power laser gain medium in a similar capacity as the alkali metals in Diode Pumped Alkali Lasers. A capacitively coupled radio frequency discharge was used to light plasma from naturally abundant xenon, thus exciting the 6s[3/2]₂ metastable state. The metastable xenon was probed with a …

The Design Of An Apparatus For The Experimental Testing Of Nucleate Boiling In Microgravity, Eric Becnel

Theses

Nucleate and pool boiling in microgravity is an area of interest due to the increase in heat transfer that this regime provides on Earth. An apparatus to experimentally test these properties may enable an increase of use of boiling in microgravity. The design, functional testing, and re-design of an apparatus to test the properties of boiling in microgravity is presented. An uncertainty analysis provides an understanding of the confidence in the performance of the instrument. The outcome of this research has shown several areas of improvement of the apparatus.

Vision Based Control Of Autonomous Underwater Vehicles, Karansingh Thakur

Theses

Vision based control (Visual Servoing) of an autonomous 6-DOF vehicle is considered in this thesis. The vehicle is to be navigated underwater using the cameras mounted on its body. With the new developed algorithm, the need for underwater GPS, Tilt Sensors and other costly devices is eliminated. The new algorithm overcomes the shortcomings of the existing algorithms, PBVS (Position-Based Visual Servoing) and IBVS (Image-Based Visual Servoing). The underwater vehicle is navigated using the image feedback obtained from the cameras. These image features are fed to the control system on the vehicle which in turn generates the desired motion. Simulations runs …

Stability And Well-Posedness Of A Rate-Dependent Damage Model For Brittle Materials, Abraham B. Kunin

Theses

This thesis presents an analysis of the stability and well-posedness of the Dominant Crack Algorithm (DCA) model for damage in brittle materials. The DCA model's prediction for the behavior of a brittle material under uniaxial tension forms the basis of the analysis. It is shown through the perturbation analysis of a one-dimensional steady-state solution that the DCA model reflects the underlying instability of the material but is mathematically well-posed. Thus perturbations to the steady-state solution remain bounded in finite time. This result has an important implication in the numerical solution of the initial boundary-value problems implicit in the DCA model. …

Detection Of Personnel And Small Arms Fire Using Pulse Radar, Joshua Bonner

Theses

The scope is to fill in a gap of detecting targets using low power, small size radars. The main objective of this thesis is to show, through simulation, that a small, low power radar can be theoretically designed using standard radar principles to accomplish said task. The primary method used in this thesis is to ascertain the conclusion with two separate Matlab Simulations. First, the design of a radar to detect human sized targets moving along the ground and secondly, detection of small arms fire aimed towards helicopters were used as the primary examples. The results show that a human …

Natural Disaster-Risk Assessment Hinesville Georgia, Assana Magagi-Alio

Georgia Municipal Association Practicum (2013-2022)

No abstract provided.

Automated Parameter Tuning Framework For Heterogeneous And Large Instances: Case Study In Quadratic Assignment Problem, Linda Lindawati, Zhi Yuan, Hoong Chuin Lau, Feida Zhu

Research Collection School Of Computing and Information Systems

This paper is concerned with automated tuning of parameters of algorithms to handle heterogeneous and large instances. We propose an automated parameter tuning framework with the capability to provide instance-specific parameter configurations. We report preliminary results on the Quadratic Assignment Problem (QAP) and show that our framework provides a significant improvement on solutions qualities with much smaller tuning computational time.

How Strong Are The Effects Of Technological Disruption? Smartphones' Impacts On Internet And Cable Tv Services Consumption, M. R. Chang, Robert J. Kauffman, K.S. Kim

Research Collection School Of Computing and Information Systems

Emerging technologies have created disruptions in organizational, business process and industry contexts. They act as shocks to a system. We focus on a retail telecom service provider’s offerings of different bun-dles, including mobile phones, Internet and cable TV services. We conduct empirical regularities analysis for Singapore, which was affected by the emergence of smartphones in 2009. We assess the impacts on the service bundle choices of a provider’s customers. We analyze customer switching among service bundles involving three services. We compute switching proba-bilities for each of the service levels offered, as well as between bundles. We use Markov chain transition …