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2013

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Articles 421 - 450 of 11462

Full-Text Articles in Physical Sciences and Mathematics

Molecular Dynamics Simulations Using Advanced Sampling And Polarizable Force Fields, Tugba Kucukkal Dec 2013

Molecular Dynamics Simulations Using Advanced Sampling And Polarizable Force Fields, Tugba Kucukkal

All Dissertations

Molecular dynamics (MD) simulations were carried out for aqueous dipeptides, water over self-assembled monolayer (SAM) surfaces, and the nicotinic acetylcholine receptor (nAChR) ion channel. The main goal is to use advanced methods to increase the accuracy of molecular dynamics simulations while seeking solutions to problems relevant to chemistry, biophysics and materials science. In addition, activation energies of several cyclodimerization reactions were studied quantum mechanically. The simulations of the aqueous dipeptides and SAM surfaces involve modeling and detailed analysis of interfacial water, which is of interest to a range of fields from biology to materials science. For example, water has a …

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Ecology And Impacts Of Coyotes (Canis Latrans) In The Southeastern United States, Cady Etheredge Dec 2013

Ecology And Impacts Of Coyotes (Canis Latrans) In The Southeastern United States, Cady Etheredge

All Dissertations

Recent coyote (Canis latrans ) colonization of the southeastern United States has prompted speculation on the top-down effects of a new top predator on systems which have gone without a strong predator presence since the extirpation of the red wolf (Canis rufus ). This dissertation reports on the results of a series of investigations of the potential impact of coyotes on raccoons (Procyon lotor ) and other management issues related to coyotes in the Southeast. Chapters 1-3 present indirect field tests of the Mesopredator Release Hypothesis. Chapter 4 presents an overview of the current knowledge of the …

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Factors Affecting The Surface-Mediated Reduction Of Plutonium In The Presence Of Pure Mineral Phases, Amy Hixon Dec 2013

Factors Affecting The Surface-Mediated Reduction Of Plutonium In The Presence Of Pure Mineral Phases, Amy Hixon

All Dissertations

The overall objective of the research is to investigate the mechanistic and kinetic aspects of the surface-mediated reduction of plutonium. The first chapter is a critical review of plutonium sorption to pure mineral phases. The objective is to study if and how the mechanisms by which plutonium interacts with mineral surfaces are connected to mechanisms for the surface-mediated reduction of plutonium. The main conclusion of the review is that advanced spectroscopy, microscopy, and molecular modeling are needed to fully understand not only the surface structure of pure mineral phases, but also the coordination and bonding environment of plutonium surface complexes. …

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Arachidonic Acid Reverses The Pyriproxyfen And Ibuprofen Induced Toxicity In Daphnia Magna, Gautam Kumar Ginjupalli Dec 2013

Arachidonic Acid Reverses The Pyriproxyfen And Ibuprofen Induced Toxicity In Daphnia Magna, Gautam Kumar Ginjupalli

All Dissertations

Healthy reproduction and neonatal sex ratios of Daphnia are crucial to the health of the aquatic ecosystems in which Daphnia play principal roles in trophic transfer of nutrients. Combinations of environmental factors such as availability and quality of diet, overcrowding, hypoxia, reduced photoperiods and fall in ambient temperatures perturb normal parthenogeneic reproduction and induce sexual reproduction through male production. Male production provides a mechanism for overcoming specific stressors such as overcrowding and overwinter pond desiccation. However, it also induces a decrease in the Daphnia population that could have adverse implications on the pond ecosystem that depend on Daphnia . Interestingly, …

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An Investigation Into The Interactions Of Gold Nanoparticles With Aquatic Vascular Macrophytes, James Glenn Dec 2013

An Investigation Into The Interactions Of Gold Nanoparticles With Aquatic Vascular Macrophytes, James Glenn

All Dissertations

Nanomaterials (NMs) have promised lighter, stronger, smaller and more efficient products in areas such as electronics, medicines and even environmental sectors. This investigation started at the base of the food chain and characterized NMs interactions with aquatic plants. Citrate capped gold nanoparticles were used as a model nanoparticle to track fate and gain insight on factors that influence gold nanoparticle (AuNP) bioavailability and absorption. Four species of aquatic macrophytes were investigated. Azolla caroliniana, Myriophyllum simulans, Egeria densa and Myriophyllum aquaticum were selected due to growth habitat, leaf morphology and root structure. Because aquatic plants absorb the majority of their nutrients …

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Chemical Evolution Of The Neutron-Rich Iron-Group Isotopes And Implications For The Formation Of Fun Cais, Tianhong Yu Dec 2013

Chemical Evolution Of The Neutron-Rich Iron-Group Isotopes And Implications For The Formation Of Fun Cais, Tianhong Yu

All Dissertations

Calcium-aluminum-rich inclusions (CAIs) are millimeter-sized refractory objects found in primitive meteorites. CAIs are considered as some of the first solids to form in the solar system, because they are refractory. FUN CAIs, those with Fractionated and Unknown Nuclear effects, are a small subset of CAIs. These FUN CAIs show correlated excesses and deficits in the neutron-rich iron-group isotopes such as 48 Ca and 50 Ti which regular CAIs do not. Interestingly, these isotopes are most likely produced infrequently but in huge quantities in a rare class of thermonuclear (Type Ia) supernovae. I propose that the isotopic effects in the neutron-rich …

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L1 Methods For Shrinkage And Correlation, Jie Shen Dec 2013

L1 Methods For Shrinkage And Correlation, Jie Shen

All Dissertations

This dissertation explored the idea of L1 norm in solving two statistical problems including multiple linear regression and diagnostic checking in time series. In recent years L1 shrinkage methods have become popular in linear regression as they can achieve simultaneous variable selection and parameter estimation. Their objective functions containing a least squares term and an L1 penalty term which can produce sparse solutions (Fan and Li, 2001). Least absolute shrinkage and selection operator (Lasso) was the first L1 penalized method proposed and has been widely used in practice. But the Lasso estimator has noticeable bias and is inconsistent for variable …

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Tomato Worker Ergonomics: Reba Panel Evaluation Of Job Tasks Using Video., Leaann Nichole Manz Dec 2013

Tomato Worker Ergonomics: Reba Panel Evaluation Of Job Tasks Using Video., Leaann Nichole Manz

Undergraduate Honors Theses

This project tested the hypothesis that non-experts' rankings of ergonomic stressors differ from those of health professionals. Tennessee ranks fifth in the production of tomatoes, an industry in which stoop labor, hand harvesting, and packing predominate. Specific parts of tomato workers' bodies are at risk of ergonomic injury such as, shoulders (loads), backs (stoop labor), lower extremities (posture), and upper extremities (repetitive motion). Of equal importance is our expectation that the scores assigned by non-experts will correlate with those of experts, leading to a community consensus for action and practical intervention research. Video footage of harvesting and sorting was analyzed …

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Design And Synthesis Of Solid State Materials Constructed From Transition Metals And Diphosphonate Or Organoarsonate Ligands, Tiffany Marie Smith Dec 2013

Design And Synthesis Of Solid State Materials Constructed From Transition Metals And Diphosphonate Or Organoarsonate Ligands, Tiffany Marie Smith

Dissertations - ALL

This work encompasses detailed investigations of the synthesis and structures of transition metal complexes which contain xylyldiphosphonate or organoarsonate ligands. The xylyldiphosphonate families of materials which were examined were the metal(II) series of Cu, Ni, Co, Mn, Cd and Zn, with an addition of an organo-nitrogen chelate. With success in these families of materials, a secondary metal of vanadium or molybdenum was added to these metal(II) systems to increase the complexity of the structure produced. For the organoarsonate series of compounds, the chemistry of the Mo/metal(II)/organoarsonate/organo-nitrogen chelate family of materials was expanded upon and preliminary studies were conducted into the …

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Singapore Management University Wins Inaugural Teradata University Network Teaching Innovation Award, Singapore Management University Dec 2013

Singapore Management University Wins Inaugural Teradata University Network Teaching Innovation Award, Singapore Management University

SMU Press Releases

Teradata Corporation, a leading global provider of analytic data platforms, marketing applications and analytics related consulting services, announced today the winner of the 2013 Teradata University Network (TUN) Teaching Innovation Award. Associate Professor Michelle Cheong and Mr Murphy Choy from the School of Information Systems at Singapore Management University (SMU) received the Award for their teaching case on "Effective Use of Data & Decision Analytics to Improve Order Distribution in a Supply Chain".

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Mathematical Modelling Of Blood Flow Through Catheterized Artery Under The Influence Of Body Acceleration With Slip Velocity, S. U. Siddiqui, Sapna Geeta Dec 2013

Mathematical Modelling Of Blood Flow Through Catheterized Artery Under The Influence Of Body Acceleration With Slip Velocity, S. U. Siddiqui, Sapna Geeta

Applications and Applied Mathematics: An International Journal (AAM)

The flow of blood through stenosed catheterized artery with the effect of external body acceleration has been considered. The pulsatile flow behaviour of blood in an artery subjected to the pulsatile pressure gradient and slip velocity has been studied considering blood as a Newtonian fluid. The non-linear differential equations governing the fluid flow are solved using the perturbation method. The analytic expressions are derived for the velocity profile, flow rate, wall shear stress and effective viscosity. The computer codes are developed for the analysis of physiological parameters. The effects of various parameters on blood flow are discussed through graphs. It …

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Relation Between Hilbert Algebras And Be–Algebras, A. Rezaei, A. B. Saeid, R. A. Borzooei Dec 2013

Relation Between Hilbert Algebras And Be–Algebras, A. Rezaei, A. B. Saeid, R. A. Borzooei

Applications and Applied Mathematics: An International Journal (AAM)

Hilbert algebras are introduced for investigations in intuitionistic and other non - classical logics and BE -algebra is a generalization of dual BCK -algebra. In this paper, we investigate the relationship between Hilbert algebras and BE -algebras. In fact, we show that a commutative implicative BE -algebra is equivalent to the commutative self distributive BE -algebra, therefore Hilbert algebras and commutative self distributive BE -algebras are equivalent.

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Asymptotic Properties Of Solutions Of Two Dimensional Neutral Difference Systems, Thiagarajan Revathi Dec 2013

Asymptotic Properties Of Solutions Of Two Dimensional Neutral Difference Systems, Thiagarajan Revathi

Applications and Applied Mathematics: An International Journal (AAM)

In this paper we obtain sufficient conditions for the asymptotic properties of solutions of two dimensional neutral difference systems. Our result extends some existing results in the literature. An example is given to illustrate the result.

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Spread Of Malicious Objects In Computer Network: A Fuzzy Approach, Bimal K. Mishra, Apeksha Prajapati Dec 2013

Spread Of Malicious Objects In Computer Network: A Fuzzy Approach, Bimal K. Mishra, Apeksha Prajapati

Applications and Applied Mathematics: An International Journal (AAM)

We propose an e-epidemic fuzzy SEIQRS (Susceptible-Exposed-Infectious-Quarantine- Recovered-Susceptible) model for the transmission of malicious codes in a computer network. We have simulated the result for various parameters and analyzed the stability of the model. The efficiency of antivirus software and crashing of the nodes due to attack of malicious code is analyzed. Furthermore, initial simulation results illustrate the behavior of different classes for minimizing the infection in a computer network. It also reflects the positive impact of anti-virus software on malicious code propagation in a computer network. The basic reproduction number R0 f and its formulation is also discussed.

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The Imperative Of Conserving California's Foothill Oak Woodlands, Lauren Phillips Dec 2013

The Imperative Of Conserving California's Foothill Oak Woodlands, Lauren Phillips

Social Sciences

No abstract provided.

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Inferring Tidal Wetland Stability From Channel Sediment Fluxes: Observations And A Conceptual Model, Nk Ganju, Nj Nidzieko, Matthew L. Kirwan Dec 2013

Inferring Tidal Wetland Stability From Channel Sediment Fluxes: Observations And A Conceptual Model, Nk Ganju, Nj Nidzieko, Matthew L. Kirwan

VIMS Articles

Anthropogenic and climatic forces have modified the geomorphology of tidal wetlands over a range of timescales. Changes in land use, sediment supply, river flow, storminess, and sea level alter the layout of tidal channels, intertidal flats, and marsh plains; these elements define wetland complexes. Diagnostically, measurements of net sediment fluxes through tidal channels are high-temporal resolution, spatially integrated quantities that indicate (1) whether a complex is stable over seasonal timescales and (2) what mechanisms are leading to that state. We estimated sediment fluxes through tidal channels draining wetland complexes on the Blackwater and Transquaking Rivers, Maryland, USA. While the Blackwater …

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Elementary Differential Equations, William F. Trench Dec 2013

Elementary Differential Equations, William F. Trench

Faculty Authored and Edited Books & CDs

No abstract provided.

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Constraints On A Second Planet In The Wasp-3 System, G. Maciejewski, A. Niedzielski, A. Wolszczan, G. Nowak, R. Neuhäuser, J. N. Winn, B. Deka, M. Adamów, M. Górecka, M. Fernández, F. J. Aceituno, J. Ohlert, R. Errmann, M. Seeliger, D. P. Dimitrov, D. W. Latham, G. A. Esquerdo, L. Mcknight, M. J. Holman, Eric L.N. Jensen, U. Kramm, T. Pribulla, S. Raetz, T. O.B. Schmidt, C. Ginski, S. Mottola, S. Hellmich, C. Adam, H. Gilbert, M. Mugrauer, G. Saral, V. Popov, M. Raetz Dec 2013

Constraints On A Second Planet In The Wasp-3 System, G. Maciejewski, A. Niedzielski, A. Wolszczan, G. Nowak, R. Neuhäuser, J. N. Winn, B. Deka, M. Adamów, M. Górecka, M. Fernández, F. J. Aceituno, J. Ohlert, R. Errmann, M. Seeliger, D. P. Dimitrov, D. W. Latham, G. A. Esquerdo, L. Mcknight, M. J. Holman, Eric L.N. Jensen, U. Kramm, T. Pribulla, S. Raetz, T. O.B. Schmidt, C. Ginski, S. Mottola, S. Hellmich, C. Adam, H. Gilbert, M. Mugrauer, G. Saral, V. Popov, M. Raetz

Physics & Astronomy Faculty Works

There have been previous hints that the transiting planet WASP-3b is accompanied by a second planet in a nearby orbit, based on small deviations from strict periodicity of the observed transits. Here we present 17 precise radial velocity (RV) measurements and 32 transit light curves that were acquired between 2009 and 2011. These data were used to refine the parameters of the host star and transiting planet. This has resulted in reduced uncertainties for the radii and masses of the star and planet. The RV data and the transit times show no evidence for an additional planet in the system. …

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Progression Magazine, 2013 Winter, Coastal Carolina University Dec 2013

Progression Magazine, 2013 Winter, Coastal Carolina University

Progression Magazine

Magazine of the College of Science at Coastal Carolina University.

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Experimental And Theoretical Cross Sections For Molecular-Frame Electron-Impact Excitation-Ionization Of D₂, Julian C A Lower, Esam S M Ali, Susan M. Bellm, Erich Weigold, Allison L. Harris, Chuangang Ning, Don H. Madison Dec 2013

Experimental And Theoretical Cross Sections For Molecular-Frame Electron-Impact Excitation-Ionization Of D₂, Julian C A Lower, Esam S M Ali, Susan M. Bellm, Erich Weigold, Allison L. Harris, Chuangang Ning, Don H. Madison

Physics Faculty Research & Creative Works

We present both experimental and theoretical results for the dissociative ionization of D2 molecules induced by electron impact. Cross sections are determined in the molecular frame and are fully differential in the energies and emission angles of the dissociation fragments. Transitions are considered from the X1Σg+ electronic ground state of D2 to the 2sσg, 2pπu and 2pσu excited states of D2+. The experimental results are compared to calculations performed within the molecular four-body distorted-wave framework to describe the multicenter nature of the scattering process. The cross sections …

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Light Sea Fermions In Electron-Proton And Muon-Proton Interactions, Ulrich D. Jentschura Dec 2013

Light Sea Fermions In Electron-Proton And Muon-Proton Interactions, Ulrich D. Jentschura

Physics Faculty Research & Creative Works

The proton radius conundrum [Pohl, Nature 466, 213 (2010)NATUAS0028-083610. 1038/nature09250 and Antognini, Science 339, 417 (2013)SCIEAS0036-807510.1126/ science.1230016] highlights the need to revisit any conceivable sources of electron-muon nonuniversality in lepton-proton interactions within the standard model. Superficially, a number of perturbative processes could appear to lead to such a nonuniversality. One of these is a coupling of the scattered electron into an electronic vacuum-polarization loop as opposed to a muonic one in the photon exchange of two valence quarks, which is present only for electron projectiles as opposed to muon projectiles. However, we show that this effect actually is part of …

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Chemical Eor, Ibnelwaleed A. Hussein, Yujun Feng, Baojun Bai Dec 2013

Chemical Eor, Ibnelwaleed A. Hussein, Yujun Feng, Baojun Bai

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

No abstract provided.

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Assessing Trichloromethane Formation And Control In Algal-Stimulated Waters Amended With Nitrogen And Phosphorus, Clinton Mash Dec 2013

Assessing Trichloromethane Formation And Control In Algal-Stimulated Waters Amended With Nitrogen And Phosphorus, Clinton Mash

Graduate Theses and Dissertations

Nitrogen (N) and phosphorus (P) enrichments can stimulate algal growth in drinking water sources, which can cause increased production of disinfection byproduct (DBP) precursors. However, the effect of systematic N and P enrichments on DBP formation and control has not been adequately studied. In this work, we enriched samples from a drinking water source - sampled on April 5, May 30, and August 19, 2013 - with N and P to stimulate algal growth at N:P ratios covering almost five orders of magnitude (0.2-4,429). To simulate DBP-precursor removal processes at drinking water treatment plants (DWTPs), the samples were treated with …

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Reservoir Management Techniques To Enhance Biological Productivity And Protect Water Quality, Ben Alan Thompson Dec 2013

Reservoir Management Techniques To Enhance Biological Productivity And Protect Water Quality, Ben Alan Thompson

Graduate Theses and Dissertations

Three reservoirs of similar size, watershed land use, and qualitative characteristics in northwest Arkansas, USA were selected to compare the effects of chemical fertilization and pulsed artificial-upwelling on whole-lake productivity, specifically primary production and phytoplankton biomass. Numerous water quality parameters were quantified over a two year period (2011-13) with the goal of understanding how each management technique would stimulate productivity. This experiment was the first step towards a larger goal to ultimately enhance sport fish production. The first year of monitoring occurred in 2011 and served as a control year for the three lakes. Treatments were initiated in two of …

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Sedimentary Provenance Of The Wedington Member, Fayetteville Shale, From Age Relations Of Detrital Zircons, William Tyson Cains Dec 2013

Sedimentary Provenance Of The Wedington Member, Fayetteville Shale, From Age Relations Of Detrital Zircons, William Tyson Cains

Graduate Theses and Dissertations

U-Pb geochronology of detrital zircons collected from the Chesterian Wedington Sandstone allows interpretation of sediment provenance and dispersal patterns in the southern midcontinent during the Late Mississippian. Detrital zircons analyzed from six samples of Wedington Sandstone yielded a final result of 565 concordant analyses used for interpretation. Results are plotted as Probability-Density Plots to interpret the spectrum of ages. Significant peaks occurred at 350-500 Ma, 950-1250 Ma, 1300-1500 Ma, 1600-1800 Ma, 1800-2300 Ma, and >2500 Ma. These peaks are interpreted as sourced by crystalline rocks within the Laurentian craton from Taconic-Acadian, Grenville, Midcontinent Granite-Rhyolite, Yavapai-Mazatzal, Paleoproterozoic, and Superior Provinces. The …

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Assessing The Impact Of Chlorine Residual On Trihalomethane And Haloacetonitrile Formation Under Chlorination And Chloramination Disinfection Regimes, Thien Duc Do Dec 2013

Assessing The Impact Of Chlorine Residual On Trihalomethane And Haloacetonitrile Formation Under Chlorination And Chloramination Disinfection Regimes, Thien Duc Do

Graduate Theses and Dissertations

A disinfection byproduct (DBP) formation potential (FP) test can be used to indirectly measure the concentration of DBP precursors in natural waters, permitting assessment of various DBP-related treatment processes and control strategies. While these tests require a 7-day chlorine residual (CR) between 3-5 mg L-1 as Cl2, it is not well known if this recommended residual corresponds to the true DBPFP (i.e., the maximum concentrations) for trihalomethanes (THMs) and haloacetonitriles (HANs). In this study, THMs and HANs were quantified as a function of CR under three common disinfection regimes: (1) free chlorine at pH 7.0 (FC7), (2) …

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Bacterially-Mediated Formation Of Rock Coatings In Kärkevagge, Swedish Lapland: A Mineralogical And Micro-Environmental Analog For Mars, Cassandra L. Marnocha Dec 2013

Bacterially-Mediated Formation Of Rock Coatings In Kärkevagge, Swedish Lapland: A Mineralogical And Micro-Environmental Analog For Mars, Cassandra L. Marnocha

Graduate Theses and Dissertations

The search for past or present life on Mars is, for now, limited to surface environments. An often neglected surface environment that could have served as an abode for life and could presently preserve evidence of that life is that of rock coatings. Rock coatings are mineral accretions on rock surfaces. On Earth, they are widespread and occur with considerable chemical diversity. There is growing evidence for a biotic role in their formation on Earth, particularly with respect to rock varnish. As a result, rock varnish has become a target of astrobiological interest on Mars, where varnish-like coatings have been …

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Consumer Adoption Of Health Information Systems, Sankara Subramanian Srinivasan Dec 2013

Consumer Adoption Of Health Information Systems, Sankara Subramanian Srinivasan

Graduate Theses and Dissertations

At nearly 18 percent of the country's GDP, the U.S. healthcare industry continues to wrestle with growing cost and a quality of care that does not match the increased spending. The dominant focus to date has been on promoting Health IT (HIT) system implementation and digitizing health records at the provider's end, with scant attention to the role of the patient in the healthcare process. The source of inefficiency in the healthcare system is not only on account of shortcomings at the provider's end but also due to non-compliance (such as failing to adhere to medication advice and follow-up visits) …

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Long-Term Residue And Water Management Effects On Soil Respiration And Soil Aggregate Stability In A Wheat-Soybean, Double-Crop System In Eastern Arkansas, Sharon Faye Smith Dec 2013

Long-Term Residue And Water Management Effects On Soil Respiration And Soil Aggregate Stability In A Wheat-Soybean, Double-Crop System In Eastern Arkansas, Sharon Faye Smith

Graduate Theses and Dissertations

Sustainability in agriculture is paramount to assuring continued production from our most naturally fertile soils. Storing carbon (C) in soil as organic matter through sustainable agricultural management practices can both remove atmospheric C and improve soil quality. The objective of this study was to evaluate the long-term effects of water management (irrigation and dryland), residue management [burn and no-burn, conventional (CT) and no-tillage (NT)] and residue/fertility level (high and low) on soil respiration and aggregate stability in a wheat- (Triticum aestivum L.) soybean [Glycine max (L.) Merr.], double-crop system in a silt-loam soil (Aquic Fraglossudalf) in the Mississippi River Delta …

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Workforce Preparedness Of Information Systems Students: Perceptions Of Students, Alumni, And Employers, Susan Bristow Dec 2013

Workforce Preparedness Of Information Systems Students: Perceptions Of Students, Alumni, And Employers, Susan Bristow

Graduate Theses and Dissertations

Employers of newly hired higher education graduates report their new workforce is not prepared. Further research was required to discover insights to the workforce readiness gap. This concurrent mixed methods study explored what competencies influenced employer's perceptions of the work-readiness of Information Systems (ISYS) undergraduate students and discovered ISYS graduates' and current ISYS students' perceptions of their work-readiness. Participants consisted of a convenience sample including 69 ISYS program upperclassmen, 20 ISYS program alumni, and 8 employers of the ISYS program graduates. ISYS program alumni completed an online Qualtrics survey to measure the participants' perception of their workforce preparedness. ISYS program …

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