28360 research outputs found
Sort by
A Study of Locally D-optimal Designs for the Emax Model with Heteroscedasticity
Get PDFThe classic theory of locally optimal designs is developed on the center+error model assuming Gaussianity and homoscedasticity for random error, in which, the Maximum Likelihood Estimator (MLE) turns out to be the most efficient in model parameter estimation. However, these assumptions are typically absent in practice. In this work, we study the locally D-optimal design based on our new oracle Second-order Least Square Estimator (SLSE). We compare asymptotic efficiency of locally D-optimal designs obtained via SLSE, the Maximum quasi-Likelihood Estimator (MqLE) and Maximum Gaussian Likelihood Estimator (MGLE), in the case where the underlying probability distribution of response is non-Gaussian and heteroscedastic. We find that even with less stringent assumptions, asymptotic efficiency of the locally D-optimal designs obtained via MqLE is comparable to oracle SLSE in some cases, albeit lesser in general. As a demonstration of how the locally D-optimal design is numerically found, we apply our feasibility-based particle swarm optimization algorithm to the locally D-optimal design based on the original SLSE
Are Infrared Thermography, Automated Feeding Systems, And Heart Rate Variability Measures Capable of Characterizing Group-Housed Sow Social Hierarchies?
Get PDFGroup gestation housing is becoming standard practice in commercial swine production. Although group housing promotes behavioral variability within the breeding herd, it can cause several management challenges for producers due to the establishment of the social hierarchy. Poor performance and welfare in group housed breeding stock can be attributed to the repercussions of aggression performed between dyads. The ability to quickly identify sows in the social hierarchy could be beneficial to producers for enforcing preventative actions. Precision livestock farming tools have proven to aid animal caretakers in monitoring animal health and welfare in livestock industries.The objective of this thesis was to investigate the use of infrared thermography, feeding activity obtained from an automated radiofrequency identification feeding system, and heat rate variability indices for detecting the social hierarchy within groups of gestating sows. Additionally, the relationship between observed social hierarchy, body condition scores, backfat, and reproductive performance was also explored
Study of Freezing Tolerance After Cold Acclimation Followed by Deacclimation in Winter and Spring Canola (Brassica napus L.)
Get PDFWinter canola/rapeseed (Brassica napus L.) produced 20 to 30% greater yield over spring canola. It overwinters to flower in spring. The winter type shows increased freezing tolerance after cold acclimation, which is crucial to survive in winter. However, short duration warm spells can cause canola to lose increased freezing tolerance in a process called ?deacclimation? making it again vulnerable to freezing damage. We found canola almost completely deacclimated at 13?C or more for at least two days of deacclimation. However, longer duration of deacclimation (7 & 14 days) showed increased freezing tolerance as compared to 2 & 3 days at 10?C or less. Variation was seen among winter varieties for deacclimation seems unrelated to cold acclimation ability. Previous genome wide association studies implicated VERNALIZATION INDEPENDENCE 3 (VIP3) as having a potential role in deacclimation. We demonstrated that mutations in VIP3 makes Arabidopsis more tolerant to deacclimation. Deacclimation resistant and susceptible varieties could be used for further study to better understand deacclimation on genetic and physiological level
Intra- and Inter-Specific Variation in Plant Responses to Climate Change
Get PDFPlants are sensitive to changing climates and are vulnerable to environmental conditions. In many regions, climate change is shifting temperatures and precipitation patterns, both of which affect various traits in living organisms, including those linked to survival and reproduction. Understanding how plants respond to climate change is increasingly important for conservation efforts. We addressed sources of trait variation and the responses utilized to cope with changing conditions within and among plant species in three different studies. We found evidence of local adaptation in temperature tolerance presumably due to divergent selection across geographic distance in Solanum carolinense. In the same species, we found phenotypic plasticity in reproductive traits when exposed to heat. Lastly, we determined that flowering phenology is driven by temperature in tallgrass prairie herbs rather than winter precipitation. These studies provide examples of how plant species are vulnerable to changing temperatures but have the capacity to adapt or acclimate
Adaptive Management as a Tool in the Restoration of Grassland, Wetland, and Riparian Ecosystems within the Northern Great Plains
No full textFour individual restoration projects were conducted across grassland, wetland, and riparian ecosystems in the Northern Great Plains, with common themes of adaptive management and enhancing native plant species presence. The first project, a grassland restoration, assessed interseeding treatment combinations to evaluated influences on plant community composition. The second grassland restoration focused on revegetation efforts utilizing multiple seed mixes on a highly modified site and looked to understand influences on species establishment and invasive species control. A wetland restoration project was conducted employing varying levels of treatment intensities with goals of establishing native vegetation in an invasive dominated site. The last project evaluated the potential to use riparian grazing as a means of stream restoration with goals of increasing floodplain accessibility and stream stability. Given the essential ecosystem services each system provides, it is important to conduct restoration studies to understand mechanisms supporting the continued rehabilitation of degraded systems
An Analysis of CPR Performance, Self-Efficacy, and Deliberate Feedback
Get PDFDuring sudden cardiac arrest (SCA), prompt initiation of cardiopulmonary resuscitation (CPR) by a healthcare provider or layperson is critical to a patient?s odds of survival.4 The absence of health care providers in athletic settings often leaves coaches as the primary responder in competitive or recreational athletics. The goal of this study was to determine if coaches could provide high-quality CPR. Twenty coaches completed confidence and deliberate feedback questionnaires before and after two sessions of 5 minute compression-only CPR. Data were analyzed to compare confidence pre and post CPR assessment, as well as to determine the relationship between CPR performance, self-efficacy, and deliberate feedback. After receiving feedback on the initial five minutes of compression-only CPR as well as completion of a one-minute bout of CPR with deliberate feedback, a strong, positive relationship between self-efficacy and quality of CPR performance was observed
Artificial Intelligence-Empowered Structural Health Monitoring, Damage Diagnosis, and Prognosis of Metallic Structures
Get PDFetallic structures are the key backbone of the society and economy, which are often subjected to different types of loadings resulting cracking, corrosion, and other material discontinuity, and affecting structural integrity and safety. Therefore, ultrasonic guided wave (UGW) has been widely used for structural health monitoring (SHM) to gain a deep understanding of structural performance, assess the current state of structural conditions, and avoid potential catastrophic events.
Despite advances in technologies and methods in data process, microdamage detection still posts great challenges in their detectability. Different from conventional physics-based methods, artificial intelligence and machine learning (AI/ML) has recently fueled profound automation solutions toward signal process and data fusion, thereby dramatically overcoming the limits.
Along this vein, this study aims to propose AI-empowered SHM framework by decoding the UGW to uncover complex interconnected information among data, models, uncertainty, and risk for enhanced structural diagnosis and prognosis to improve metallic structural integrity and safety. Several structural cases, from one-dimensional plates/rods to three-dimensional pipes, were deliberately selected to demonstrate the real-world applications. Three different levels of the AI/ML approaches, from shallow learning to deep learning, are used to explore the effectiveness of the data fusion and data representation. Meanwhile, noise interference and structurally initial nonlinearity as typical structural uncertainty are included in data collection to understand the effects of data quality and uncertainty on the robustness of the proposed methods.
The results showed that the proposed method was an efficient and accuracy way to identify the damage characteristics. Results from the shallow learning demonstrated that different features had certain levels of sensitivity to damage, while the feature selection method in the shallow learning revealed that time-frequency features and wavelet coefficients exhibited the highest damage-sensitivity. However, with the increase of noise level, the shallow learning failed in detectability.
By taking advantage of higher automation in feature extraction, the deep learning exhibited significant improvement in accuracy, robustness, and reliability for structural diagnosis and prognosis. Particularly, the higher-layer architecture could outperform the shallow learning in terms of higher effective and efficient data fusion, and enhanced their capability in decoding information over noise interference and structural uncertainty
Correlation Between Crack Density in Paste and Drying Shrinkage in Concrete
Get PDFConcrete shrinks during drying and chemical changes, and if this shrinkage is restrained, cracks are formed, thereby affecting the long-term durability of concrete. The conventional methods of shrinkage measurement require considerable space, materials, and resources. This research aims to explore the relationship between drying shrinkage in concrete and crack density in the cementitious paste system. A model is developed, which uses cement paste samples instead of concrete samples for testing, resulting in a potentially faster, more efficient, and convenient testing method. The model provides relationships that predict the estimated net time to crack and average stress rate in concrete by using the crack density values in cement paste. Four different cementitious combinations made from Type-IL and CG-P cement were investigated for restrained shrinkage in concrete specimens and micro-crack density in paste samples. The effects of supplementary cementitious materials, namely Silica Fume (SF) and Shrinkage Reducing Admixtures (SRA) were also investigated
Sex Differences in Response to a Large 200-Person Audience using the Trier Social Stress Test in Pre-Recorded Virtual Reality
Get PDFThe Trier Social Stress Test (TSST) induces stress in the lab by having participants complete challenging tasks in front of an audience. The TSST has been adapted to virtual reality (VR), eliminating in-person audience variability that could explain sex differences in stress responses. Furthermore, the VR-TSST facilitates the examination of factors difficult to investigate in person, such as the effect of a large, 200-person audience. This study compared male and female physiological and psychological responses to an in-person 2-person TSST and a prerecorded VRTSST with audience sizes of 2 and 200 persons. Results indicated that only males had statistically significant cortisol reactivity to the TSST and responded with more positive affect, arousal, and lower ratings of stress than females. In the VR conditions these differences were less apparent, suggesting that the sex differences may be a result, at least in part, of in-person audience variability
An Evaluation of Feeding Hempseed Cake in Finishing Cattle Diets
Get PDFUnderstanding the potential of hempseed cake to be used as a livestock feedstuff is important for both industrial hemp and beef producers. Experiment 1 evaluated the effects of hempseed cake (HEMP) on growth performance, feeding behavior, plasma metabolite concentrations across time, and carcass characteristics when fed in finishing diets to heifers in comparison to dried corn distillers grains plus solubles (DDGS). Experiment 2 investigated the effects of HEMP on diet ruminal fermentation parameters, total tract digestibility, nutrient flow, and nitrogen balance in finishing steers in comparison to DDGS and a control (CON) diet containing no byproduct. Experiment 3 explored the effects of hempseed cake on immune parameters in response to an endotoxin (lipopolysaccharide) challenge in finishing steers in comparison to DDGS and CON. In experiment 1, the HEMP diet reduced heifer growth performance and hot carcass weight while not influencing dry matter intake, feeding behavior, or other carcass characteristics. Plasma urea nitrogen (PUN) was greater for heifers fed the HEMP diet, and glucose and total amino acid concentrations were not influence by treatment. In experiment 2, ruminal ammonia and total VFA concentrations were greatest for steers fed the HEMP diet. Furthermore, organic matter (OM) intake tended to be greater, OM total tract apparent digestibility was reduced, and N digestibility was greatest for steers fed the HEMP diet, and site of digestion was influenced by treatment. Nitrogen retention was greatest in steers fed the HEMP diet, suggesting treatment influence on N metabolism. In experiment 3, there was a treatment by hour interaction for PUN, and plasma glucose and NEFA were not influenced by treatment. Plasma IL-1?, IL-36RA, and TNF-? were lowest in steers fed the HEMP diet, and all other cytokines and total amino acid plasma concentrations were not influenced by treatment. Hempseed cake negatively influences growth performance in large part because of reduced total tract apparent OM digestibility, while N total tract apparent digestibility and N retention are improved and immune response is influenced, so further understanding of these outcomes is needed to explore implications of feeding hempseed cake to finishing cattle