Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Life Sciences (3831)
- Physical Sciences and Mathematics (2497)
- Social and Behavioral Sciences (2273)
- Engineering (1964)
- Medicine and Health Sciences (1955)
-
- Education (1423)
- Psychology (1178)
- Arts and Humanities (999)
- Biology (873)
- Chemistry (835)
- Biochemistry, Biophysics, and Structural Biology (665)
- Computer Sciences (430)
- Sociology (406)
- Biochemistry (383)
- Animal Sciences (368)
- Public Health (359)
- Biomedical Engineering and Bioengineering (355)
- Environmental Sciences (315)
- Electrical and Computer Engineering (305)
- Medical Sciences (302)
- Mechanical Engineering (275)
- Pharmacy and Pharmaceutical Sciences (273)
- Plant Sciences (264)
- Clinical Psychology (262)
- Civil and Environmental Engineering (255)
- Earth Sciences (252)
- Physiology (247)
- Ecology and Evolutionary Biology (236)
- Microbiology (234)
- Cell and Developmental Biology (226)
- Institution
-
- Virginia Commonwealth University (3248)
- University of North Dakota (3017)
- Brigham Young University (2820)
- Mississippi State University (2632)
- University of South Carolina (1895)
-
- Air Force Institute of Technology (922)
- Rowan University (757)
- University of Texas Rio Grande Valley (703)
- American University in Cairo (607)
- Illinois State University (590)
- Florida Institute of Technology (472)
- University of Arkansas Little Rock (449)
- Pepperdine University (403)
- City University of New York (CUNY) (378)
- St. John's University (327)
- Columbus State University (185)
- Nova Southeastern University (144)
- SASTRA Deemed to be University (103)
- Texas A&M International University (79)
- University for Business and Technology in Kosovo (54)
- UAlaska System (2)
- CentraCare Health (1)
- Louisiana Tech University (1)
- Southern Methodist University (1)
- Keyword
-
- Education (154)
- Cancer (151)
- Gender (134)
- Depression (119)
- Machine learning (110)
-
- Dissertations (PsyD) -- Psychology (109)
- North Dakota (103)
- Inflammation (85)
- Autism (82)
- Mental health (80)
- Biological sciences (79)
- Dissertations (EdD) -- Organizational leadership (77)
- Stress (77)
- Utah (74)
- Women (74)
- United States (71)
- Obesity (69)
- Nanoparticles (65)
- Ecology (63)
- Trauma (63)
- Adolescents (62)
- Leadership (62)
- Anxiety (61)
- Apoptosis (60)
- Mitochondria (57)
- Proteomics (56)
- Development (55)
- Aging (54)
- Behavior (54)
- Breast cancer (54)
- Publication Year
- File Type
Articles 9691 - 9720 of 19790
Full-Text Articles in Entire DC Network
Cogongrass [Imperata Cylindrica (L.) Beauv.] Control Using Chemical Treatment With Cover Cropping Systems, Maria Leticia Moraes Zaccaro
Cogongrass [Imperata Cylindrica (L.) Beauv.] Control Using Chemical Treatment With Cover Cropping Systems, Maria Leticia Moraes Zaccaro
Theses and Dissertations
Cogongrass management generally requires multiple herbicide applications, however, success is limited if not integrated with other methods. Experiments were conducted to evaluate the use of cover cropping systems with herbicides on cogongrass control. Field studies determined that sequential glyphosate applications in the summer were necessary to achieve 80% or greater control, but a single application could be effective if weather conditions allowed early planting and good cover crop establishment of Roundup Ready soybeans. Studies also indicated that the use of ALS-resistant Italian ryegrass and white clover crop combinations showed no effect, but imazapyr applications made in May or June provided …
Cotton Growth And Developmental Responses To Multiple Environmental Stresses, David William Brand
Cotton Growth And Developmental Responses To Multiple Environmental Stresses, David William Brand
Theses and Dissertations
Individual and multiple stress factor effects of temperature on cotton growth and development were studied in four cotton cultivars. In Experiment I, seedling emergence rate and shoot and root morphological growth traits were measured on plants grown at five day/night temperatures from 20/12 to 40/32 °C. In Experiment II, multiple stress factors (CO2, temperature, UV-B radiation) and their interactions were evaluated during the seedling growth stage. Seed emergence and above- and below-ground growth and developmental traits were recorded in both experiments. Linear (TM-1 and PHY496W3R) and quadratic (DP1522B2XF and ST47447) functions best described seed emergence rate with an increase in …
Design Of An American Football Helmet Liner For Concussion Mitigation, Gustavus Alston Rush
Design Of An American Football Helmet Liner For Concussion Mitigation, Gustavus Alston Rush
Theses and Dissertations
The objective of this research was to develop an optimal design for a polymeric American football helmet liner for concussion prevention utilizing experiments and high performance. Along with well-established injury criteria (HIC, SI, and Peak acceleration), localized brain injury mechanisms were explored by employing Finite Element simulations and experimental validation. Varying strain rate experiments (monotonic and hysteresis) were conducted on modern football helmet (Rush, Rawlings, Riddell, Schutt, and Xenith) liners and new possible polymeric foam liner materials. These experiments were used to characterize each material at low strain rates (0.1/sec; Instron), intermediate strain rates (100-120/sec; NOCSAE drop tower) and high …
Evaluation Of An On-Farm Water Storage System As A Bmp For Sediment And Nutrient Reduction, Nutrient Recycling, And Irrigation In East Mississippi, Ritesh Karki
Theses and Dissertations
Evaluation of an On-Farm Water Storage (OFWS) system as a Best Management Practice (BMP) for nutrient and sediment loading control and irrigation in East Mississippi has shown that the system can effectively reduce sediment and nutrient loading as it was able to capture 46 tons of sediment and 558 kg of phosphorus over the monitoring period. The system was also able to decrease nitrogen loading as shown from the nitrogen concentration in the captured storm runoff events although an accurate estimate could not be made using AnnAGNPS because adequate model input data was not available. The system was able to …
Do Living Shorelines Contribute To The Accumulation Of Nutrients, Sediment, And Organic Matter Needed For The Maintenance Of Coastal Wetlands?, Saranee Dutta
Theses and Dissertations
Living shorelines are designed to address coastal erosion and their use is encouraged over that of hard structures such as sea walls and bulkheads because they provide habitat, improve water quality and stabilize shorelines. Objectives of this study were to: (i) Compare soil Nitrogen [N], Phosphorus [P], Organic Carbon [OC], organic matter (SOM) and soil bulk density between living, hardened and natural shoreline to determine if soil present within living shorelines is comprised of higher SOM and lower bulk density, that encourage marsh growth, as compared to hardened shorelines. (ii) Use an experimental mesocosm to test the effect of shoreline …
Effect Of Rooting Media, Cultivars And Genotype On The Propagation Of Blueberry, Tripti Saha
Effect Of Rooting Media, Cultivars And Genotype On The Propagation Of Blueberry, Tripti Saha
Theses and Dissertations
The objectives of this research were to study: 1) the effects of five different propagation media containing composted materials on the rooting of semi hardwood blueberry cuttings and 2) the effects of four cultivars and one genotype on rooting responses of these cuttings. The media used were: peat moss and horticulture grade per lite as control, composted pine bark fines with only one-time application of ammonium nitrate, pine bark fines with composted cotton gin waste, hardwood with and composted chicken litter and pine bark with composted chicken litter. There were no significant differences among the media for rooting from semi …
Thermal Variation And The Built Environment Of Jackson, Mississippi, Peter Jay Crank
Thermal Variation And The Built Environment Of Jackson, Mississippi, Peter Jay Crank
Theses and Dissertations
Urbanization and a changing climate have encouraged more discussion as to how the urban heat island affects humans and society. This research examines three temperature variables (air temperature, apparent temperature, and surface skin temperature) across the Jackson, Mississippi metropolitan area to determine if intra-city thermal variability in select neighborhoods and business districts is connected to the built environment of each location. Using hand-held observation equipment, official weather observations from nearby airports, and land cover data from the United States Geological Survey, this research suggests that the built environment is contributing to the thermal variability around the city; however, the fine …
Development Of Assisted Reproductive Technologies For Endangered North American Salamanders, Ruth Marie Marcec
Development Of Assisted Reproductive Technologies For Endangered North American Salamanders, Ruth Marie Marcec
Theses and Dissertations
Amphibians are key health indicator species and important sentinels for ecosystem health. With 32% of amphibians threatened with extinction, and an additional 25% without enough data on record to fully understand their status, amphibians are facing what is being called the Amphibian Extinction Crisis. Of caudate amphibians (salamanders/newts), 49.8% are threatened or endangered, making them currently the most threatened vertebrate taxa. As a result of the Amphibian Extinction Crisis, it is imperative that captive breeding facilities be established as a hedge against future amphibian extinctions. Unfortunately, captive assurance colonies face frequent failure due to lack of natural stimuli, which are …
Drivers Of Sustainable Agriculture In A Southern State, Casey William Odom
Drivers Of Sustainable Agriculture In A Southern State, Casey William Odom
Theses and Dissertations
This Master’s Thesis establishes what motivates a group of Mississippi farmers to participate in sustainable agriculture instead of industrial agriculture. A database of sustainable farmers was constructed in collaboration with the Gaining Ground Sustainability Institute of Mississippi. This research project used social network analysis with 28 farmers and participant observation and semi-structured interviewing with a purposively selected sample of 14 farmers. This project also explores the sustainable agricultural practices of participants. A map of the social network of sustainable agriculturalists in Mississippi is presented and shows that some farmers are well connected, some moderately connected, and others are isolated. As …
Functions Of Wetland Plant Assemblages On Water Quality Improvement, Evelyn Louise Windham
Functions Of Wetland Plant Assemblages On Water Quality Improvement, Evelyn Louise Windham
Theses and Dissertations
Studies have shown wetlands act as filters for nutrient rich waters, in part due to macrophyte properties. Differences have been found in nitrogen removal rates among plant species in studies of monocultures grown in mesocosms mimicking wastewater treatment constructed wetlands, but little research has been done on assemblages in natural or restored wetlands. This study aims to identify differences in water quality among plant assemblages in natural and restored wetlands. Thirty natural and restored wetlands in the Mississippi portion of the Mississippi Alluvial Valley were sampled four times. Water quality was measured and plant assemblages identified. Significant differences in pH, …
Influence Of Velocity On Weimaraner Trotting Mechanics, Leif Carlisle
Influence Of Velocity On Weimaraner Trotting Mechanics, Leif Carlisle
Theses and Dissertations
While Weimaraner size may assist in the performing of tasks of a sporting dog, it also makes the breed more susceptible to hip dysplasia. However, this breed has a lower rate of dysplasia. This may be due to selected gait velocity and mechanics specific to the breed, but gait analysis of Weimaraners is lacking. Study objectives were to define normal trotting mechanics and to determine the influence of velocity on gait. Dogs were trotted at a slow and fast trot and at both velocities. The trot had a diagonal footfall sequence with a 2-beat rhythm alternating between diagonal bipedal support …
Landscape Ecology Of Eastern Wild Turkeys In Mississippi, Annie Moriah Davis
Landscape Ecology Of Eastern Wild Turkeys In Mississippi, Annie Moriah Davis
Theses and Dissertations
The effects of landscape structure on wildlife populations have drawn more attention from ecologists and wildlife managers as landscapes have rapidly changed worldwide. The objectives of this study were to (1) conduct a statewide habitat suitability assessment for wild turkeys (Meleagris gallopavo) in Mississippi using machine learning methods; (2) determine landscape-abundance relationships of wild turkeys at 2 spatial scales; and (3) measure genetic distinction of wild turkey populations in Mississippi. I found that habitat suitability for wild turkeys was positively related to amount of forest cover. Wild turkey relative abundance peaked at an optimal hardwood forest proportion of 0.29 and …
Maroon And White And Read All Over Newspaper Coverage Of Desegregation Of Mississippi State Football, 1970-1973, Benjamin Joseph Downs
Maroon And White And Read All Over Newspaper Coverage Of Desegregation Of Mississippi State Football, 1970-1973, Benjamin Joseph Downs
Theses and Dissertations
This content analysis was designed to investigate newspaper coverage of the desegregation of Mississippi State varsity football through the media coverage of the first Black football players at Mississippi State University, Robert Bell and Frank Dowsing. Two hundred and three articles from three newspapers (The Starkville Daily News, Mississippi State Reflector, and Jackson Clarion-Ledger) were examined using a three-tiered qualitative analysis. That analysis resulted in 426 frame instances and 686 theme instances, or a total of 1,112 codes. The resulting data were then interpreted using Critical Race Theory (CRT) to generate understanding of the desegregation of the football program. The …
A Horticultural Therapy Program For The Elderly: Effects On Cognition, Quality Of Life, And Loneliness, Mariah Ruth Baird
A Horticultural Therapy Program For The Elderly: Effects On Cognition, Quality Of Life, And Loneliness, Mariah Ruth Baird
Theses and Dissertations
Previous studies suggest there are numerous benefits of horticultural therapy programs. The current study explored the benefits of a horticultural therapy program with elderly populations at two facilities in Bowling Green, Kentucky. Fifteen participants attended a 2-hour session on horticulture techniques once a week for four weeks. Using a pretest to posttest study design, changes in participants’ cognition, quality of life, and loneliness were assessed. The pretest was administered verbally by the researcher before the first session and the posttest, including a series of questions about satisfaction with the program, was administered after the last session. Items on each assessment …
A Novel Microextraction Method For Determining The Presence Of Pentachlorophenol In An Ongoing In-Situ Groundwater Remediation, Julianna Nicole Stratton
A Novel Microextraction Method For Determining The Presence Of Pentachlorophenol In An Ongoing In-Situ Groundwater Remediation, Julianna Nicole Stratton
Theses and Dissertations
Pentachlorophenol (penta) is a pollutant of concern worldwide. This study looks at a site that has been under remediation for the last 16 years due to penta contamination. The site has been air- and bio-sparged, phytoremediated and undergone in-situ chemical oxidation treatment in attempts to clean the ground water of penta. This thesis explores a novel microextraction method that has the promise of being more sensitive using less sample and fewer hazardous chemicals than conventional methods. Groundwater samples were extracted for phenolic compounds using a novel modified liquid microextraction protocol. Comparing our results with monitoring information from 2014, our method …
The Defense Response Of Glycine Max To Its Major Parasitic Nematode Pathogen Heterodera Glycines, Shankar R. Pant
The Defense Response Of Glycine Max To Its Major Parasitic Nematode Pathogen Heterodera Glycines, Shankar R. Pant
Theses and Dissertations
Heterodera glycines, soybean cyst nematode (SCN) causes more than one billion dollars soyben production loss in the U.S. annually. SCN is an obligate parasite of specialized feeding cells within the host root known as syncytium. The SCN resistance genes and signaling pathways in soybean have not been fully characterized. Gene expression analysis in syncytium from compatible and incompatible interactions identified candidate genes that might involve conferring resistance to SCN. This dissertation aimed to investigate the biological functions of the candidate resistance genes to confirm the roles of these genes in resistance to SCN. The study demonstrated a role of syntaxin …
The Role Of Auxin In Defense Response To Aspergillus Flavus In Zea Mays L, Seval Ozkan
The Role Of Auxin In Defense Response To Aspergillus Flavus In Zea Mays L, Seval Ozkan
Theses and Dissertations
Understanding the role of phytohormone auxin in defense responses is one of the vital tools for plant breeders to develop maize germplasm lines that exhibit high resistance to Aspergillus flavus and subsequent aflatoxin accumulation. Besides its critical role in different developmental processes throughout the life cycle of plants, auxin is also involved in the network of plant-pathogen interaction as demonstrated in previous studies. However, the actual mechanism for the auxin signaling pathway leading to resistance is unknown. Therefore, the critical gap in the knowledge base is a lack of understanding of the role of auxin signaling in pathogen resistance in …
Investigating Late Woodland-Period Aquatic Catchments Through Freshwater Mussel Assemblage Composition, Sarah K. Gilleland
Investigating Late Woodland-Period Aquatic Catchments Through Freshwater Mussel Assemblage Composition, Sarah K. Gilleland
Theses and Dissertations
During the Late Woodland Period in the American Southeast, the amount of space that any individual group could exploit began to shrink, due to the presence of other groups on the landscape. Resource expansion occurred to augment food supplies, resulting in increased exploitation of mussel beds. Because mussels can be extremely sensitive to the characteristics of the waterways they live in, the specific habitat requirements of these animals can be used to reconstruct the environments they were recovered from. In this thesis I use freshwater mussel assemblages to reconstruct hypothetical aquatic catchments and map them onto modern rivers in the …
Isotopic Study Of Diet During The Bronze And Early Iron Ages At Mitrou And Tragana Agia Triada, Greece, Stephanie Fuehr
Isotopic Study Of Diet During The Bronze And Early Iron Ages At Mitrou And Tragana Agia Triada, Greece, Stephanie Fuehr
Theses and Dissertations
The stable isotopes carbon and nitrogen from 18 skeletal and 51 dental samples from various burial contexts at the Bronze and Iron Age sites of Mitrou and Tragana Agia Triada are examined to understand diet in prehistoric central Greece. The samples are compared by cultural period, site, and burial type in order to determine if diet was affected by changes in society or by social status as determined by burial form. In addition, isotopic data from across Greece is compared to understand diet from the Neolithic to Iron Age and in different regions of the country. The results of the …
Maintaining Soil Physical Property Integrity In Turfgrass Management Systems, Jordan Michael Craft
Maintaining Soil Physical Property Integrity In Turfgrass Management Systems, Jordan Michael Craft
Theses and Dissertations
Traditional aerification programs can cause substantial damage to the playing surface resulting in prolonged recovery. A growing trend in the industry involves using aerification techniques that cause minimum surface disruption; however, despite growing interest in new and alternative aerification technology, there is a lack of information in the literature comparing new or alternative technology with traditional methods on warm season grasses. Therefore, the objective of this research was to determine the best combination of new dry-injection (DI) cultivation technology with modified traditional aerification programs to achieve minimal surface disruption without a compromise in soil physical properties. Research was conducted at …
Methodology To Measure And Compare The Efficiency Of Radiant Heaters Used In Poultry Brooding, John Emerson Linhoss
Methodology To Measure And Compare The Efficiency Of Radiant Heaters Used In Poultry Brooding, John Emerson Linhoss
Theses and Dissertations
During the first seven to ten days of life chicks are unable to maintain homeothermy, thus providing supplemental heat is critical to their livability and performance. Radiant heaters are the preferred method of providing heat during brooding because they provide a range of thermal comfort options for chicks. Infrared thermography is often used to assess the heat distribution created at the litter surface by radiant heaters. The resulting images provide a good qualitative assessment of heat distribution but do not provide any quantifiable metrics through which to compare the radiant output of heaters. Data acquisition systems were developed to measure …
Methodology To Predict Daily Groundwater Levels By The Implementation Of Machine Learning And Crop Models, Sandra Milena Guzman Gutierrez
Methodology To Predict Daily Groundwater Levels By The Implementation Of Machine Learning And Crop Models, Sandra Milena Guzman Gutierrez
Theses and Dissertations
The continuous decline of groundwater levels caused by variations in climatic conditions and crop water demands is an increased concern for the agricultural community. It is necessary to understand the factors that control these changes in groundwater levels so that we can better address declines and develop improved conservation practices that will lead to a more sustainable use of water. In this study, two machine learning techniques namely support vector regression (SVR) and the nonlinear autoregressive with exogenous inputs (NARX) neural network were implemented to predict daily groundwater levels in a well located in the Mississippi Delta Region (MDR). Results …
Novirhabdovirus Infection In Wild-Type And Rag1 Mutant Zebrafish Suggests Roles Of Lymphocytes In Resistance, Du Ngoc Nguyen
Novirhabdovirus Infection In Wild-Type And Rag1 Mutant Zebrafish Suggests Roles Of Lymphocytes In Resistance, Du Ngoc Nguyen
Theses and Dissertations
Disease development of wild-type and Rag1 mutant zebrafish was evaluated after challenge with Snakehead Rhabdovirus (SHRV), a novirhabdovirus. Rag1 mutants lack T and B lymphocytes and thus lack lymphocyte-based acquired immunity. Wild-type zebrafish became more disease resistant as they aged (4 months and older) and at an elevated temperature (28°C) but mutants remained sensitive at all ages and temperatures tested. Quantitative reverse transcription polymerase chain reaction (RT qPCR) demonstrated that interferon gamma and MxA expression significantly increased in both types of fish at 2 days post-infection with subsequent dwindling of expression. The high interferon gamma expression suggests activation of natural …
Relative Rate Of Transposable Element Insertions On The X Chromosome And Autosomes, Christopher D. Savell
Relative Rate Of Transposable Element Insertions On The X Chromosome And Autosomes, Christopher D. Savell
Theses and Dissertations
Sex chromosomes and autosomes often differ in their relative rates of evolution, with sex chromosomes generally accumulating changes more rapidly (faster-X evolution). Transposable elements (TEs) make up a significant portion of eukaryotic genomes and are some of the most rapidly evolving genetic elements. We compared relative rates of insertion on the X and autosomes for 78 families found in Drosophila melanogaster. The average X/A ratio for these TE families was 1.11, similar to the mean dS X/A ratio, indicating no male-bias in mutation rate or TE insertion. The major mode of the distribution was ~0.8, indicating stronger purifying selection on …
Rhodium Catalyzed Coupling Of In Situ Generated Alpha-Lactams With Indoles And Synthesis And Surface Immobilization Of Bis-Corannulene Molecular Receptors, K G Upul Ranjan Kumarasinghe
Rhodium Catalyzed Coupling Of In Situ Generated Alpha-Lactams With Indoles And Synthesis And Surface Immobilization Of Bis-Corannulene Molecular Receptors, K G Upul Ranjan Kumarasinghe
Theses and Dissertations
The first section of this dissertation (Chapter I-III) describes the development of new methodologies for the rhodium catalyzed C-N bond formation between sp3 hybridized carbon atom of phenyl substituted alpha-lactams and the nitrogen atom of indole derivatives. Phenyl substituted alpha-lactams generated in situ from the corresponding alpha-bromoamides reacted with indoles in the presence of rhodium catalyst to afford the ring opening products of alpha-lactams. The scope of this methodology was extended to various types of indole derivatives including electron donating and withdrawing substituents. Furthermore, a series of functionalized phenyl substituted alpha-lactams generated in situ reacted with indole to assess the …
Soybean Yield And Biomass Response To Supplemental Nitrogen Fertilization, Justin Michael Mccoy
Soybean Yield And Biomass Response To Supplemental Nitrogen Fertilization, Justin Michael Mccoy
Theses and Dissertations
Soybean (Glycine max [L.] Merr.) has become one of the main agricultural grain crops produced in the United States. Soybean production continues to increase in high-yield environments throughout the U.S. New innovations are required to sustain gains in soybean yield potential. Field experiments were conducted at the Delta Research and Extension Center in Stoneville, MS in 2014 and 2015 to evaluate soybean aboveground biomass and grain yield response to supplemental N fertilization in a high-yielding environment on two soil textures commonly cropped to soybean in Mississippi. Greenhouse studies were conducted in 2016 at the Delta Research and Extension Center in …
Spatial Correlation Between Framework Geology And Shoreline Morphology In Grand Bay, Mississippi, Asa J. Mullennex
Spatial Correlation Between Framework Geology And Shoreline Morphology In Grand Bay, Mississippi, Asa J. Mullennex
Theses and Dissertations
The Grand Bay National Estuarine Research Reserve (GBNERR) adjoins two costal embayments in the eastern Mississippi Sound, Grand Bay and Point Aux Chenes Bay, which encompass a late Pleistocene/ Holocene delta of the Pascagoula-Escatawpa fluvial system. Historical maps and aerial imagery indicate that the GBNERR shoreline has experienced long-term retreat at spatially variable rates. The research presented here investigates the relationship between the coastal geomorphological evolution of GBNERR and the underlying geological framework. Coastal morphology and stratigraphy were characterized by analyzing 85 km of chirp sonar sub-bottom seismic profiles and 45 sediment cores. Shoreline retreat rates were determined through geospatial …
Experimental-Computational Analysis Of Woodpeckers' Beaks/Hyoid Apparatus For Damping Of Stress Waves, Na Yeon Lee
Experimental-Computational Analysis Of Woodpeckers' Beaks/Hyoid Apparatus For Damping Of Stress Waves, Na Yeon Lee
Theses and Dissertations
This dissertation proposes engineering principles for stress wave dissipation found in woodpeckers. From the experimental study of a woodpecker’s beaks via electron microscopy and mechanical testing, the three main design factors were pointed out. First, a woodpecker’s beak has wavy lines inside of the beak for local shearing. The waviness of wavy lines found in the woodpecker’s beaks was 1 while chicken’s was 0.3, and toucan’s was 0.05. Second, the woodpecker showed elongated the keratin scales to the pecking direction with a dimension ratio of 3.67 (width/height) while chicken’s and toucan’s were 3 and 1, respectively. Third, a woodpecker’s beak …
From Horns To Helmets: Multi-Objective Design Optimization Considerations To Protect The Brain, Kyle Leslie Johnson
From Horns To Helmets: Multi-Objective Design Optimization Considerations To Protect The Brain, Kyle Leslie Johnson
Theses and Dissertations
This dissertation presents an investigation and design optimization of energy absorbent protective systems that protect the brain. Specifically, the energy absorption characteristics of the bighorn sheep skull-horn system were quantified and used to inform a topology optimization performed on a football helmet facemask leading to reduced values of brain injury indicators. The horn keratin of a bighorn sheep was experimentally characterized in different stress states, strain rates, and moisture contents. Horn keratin demonstrated a clear strain rate dependence in both tension and compression. As the strain rate increased, the flow stress increased. Also, increased moisture content decreased the strength and …
The Effect Of Content-Related And Unrelated Break Activities On Test Results, Ryan Gentek
The Effect Of Content-Related And Unrelated Break Activities On Test Results, Ryan Gentek
Theses and Dissertations
Researchers have recently explored using brief breaks to maintain performance during prolonged tasks (Ariga and Lleras, 2011). However, research has yet to fully explore the effect of break activity content on the performance of the primary task. The present study sought to explore the differing effects of two break activities that were respectively similar and different in content to the main task. The present researcher compared past studies of task-switching and interruption studies to theories of the vigilance decrement and hypothesized that a brief similar task should result in significantly different main-task performance than the brief dissimilar task. 20 participating …