School of Graduate Studies and Research
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Graduate Studies and Research offers a diverse array of 16 master’s and five doctoral degree programs across four academic colleges.
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Item Open Access Child welfare training: the relationship between perceived transfer of training, retention, and educational supervision of new caseworkers(Delaware State University, 2008-12) Blakey, Donna L.In order to meet the challenges that children and families often present, public child welfare organizations need trained, competent, and confident caseworkers. This study examines new caseworker training in a public child welfare organization. New caseworkers who completed preservice training while in a training unit, or in a function based unit, were queried about their perceptions regarding three factors identified in the literature as impacting training transfer; training design, opportunities to use training on the job, and educational supervision. In addition, supervisors who had received new caseworkers were questioned about their best educative supervisory approaches, and their perceptions of the influence of training on the retention of new caseworkers. Following an analysis of the data, it was concluded that there was no statistically significant difference in the perceptions of new caseworkers regarding the training transfer factors, based on their unit assignment while attending pre-service training. Yet, overall, the perceptual indicators were positive for the transfer of training, opportunities to use training, educational supervision, and the impact of training on the retention of new caseworkers.Item Open Access An exploration of government funding, alumni giving, and private fundraising’s impact on resource generation at historically black colleges and universities:a multiple case study(2016-05-22) Pickrum, VitaFunding for institutions of higher education (IHE) currently faces particularly difficult challenges the given recent economic downturns and changing perceptions of the usefulness of a college degree. At the same time, while the colleges and universities seek to grapple with the rising expectations and expanding costs, opportunities for funding appear to be lessening. Government funding, whether through federal, state or local government, has been decreasing as a result of the economic conditions at the same time that external indicators that judge higher education institutions worthy of investment become more stringent. Historically Black Colleges and Universities (HBCUs) suffer disproportionately in this environment. The mission of these institutions is to address long-term inequities in education that African-Americans, in particular, have suffered. Current indicators of a university or college’s worthiness are increasingly based on the U.S. News and World Report rankings, yet these rankings utilize measures that cast HBCUs in an especially negative light because their mission is to serve under- v resourced and predominantly first-generation college students. Institutions of higher education, and especially HBCUs in particular, must carefully examine their current resource generation methodology and make adjustments based on current realities. This study provides an in-depth case study into two HBCUs in the mid-Atlantic region and their approach to resource generation in light of this changing paradigm. It highlights the importance of moving away from a dependence on government funding to a more sustainable and independent approach that emphasizes more creative alumni giving and private fundraising. This study builds on and contributes to a strong research base that clearly shows that institutions of higher education must seek to engage alumni earlier and more actively in committing to ongoing financial support of their alma maters while also finding ways to convince potential donors, whether private individuals, corporate sponsors, or charitable organizations, of the important role that HBCUs play in educating students who have much to contribute to the improvement of American communities but suffer especially difficult challenges in achieving a college education. This study highlights several particularly important changes that HBCUs can make in their resource generation strategies that will, ideally, guarantee their usefulness and sustainability in the future.Item Open Access Mathematical methods and algorithms for identification, tracking, and quantitative analysis in cellular BioimagingZerari Boukari, FatimaAutomated cell segmentation and tracking enables the quantification of static and dynamic cell characteristics and is significant for disease diagnosis, treatment, drug development and several other domains in health and life sciences. The topic of this dissertation is the development of techniques for fully automated cell segmentation, tracking, lineage construction, and quantification. This work concentrates on two areas; cell segmentation and cell tracking. We pursue a solution of the cell segmentation problem in the joint spatio-temporal domain to overcome weaknesses of previous works that operate only on the spatial domain of each frame. Here we propose a PDE-based formulation of spatio-temporal motion diffusion to detect the cell motion. In addition, we introduce an intensity standardization technique to address intensity variability complicating frame-to-frame analysis in differential techniques. To refine cell delineation accuracy produced by motion diffusion-based segmentation, we propose to use energy minimizing geometric active contours that assume a piece-wise constant image region model as a special case of the Mumford-Shah segmentation framework. Furthermore, we introduce temporal linking of the region-based level sets to allow for faster convergence and to resolve non-convexity that affects energy-based minimization that is typical in image analysis inverse problems. In the cell tracking part of this work we first propose a variational method for joint local-global optical flow computation to estimate the cell motion. We utilize the predicted cell motion along with cell areas in a probabilistic Maximum Likelihood decision strategy assuming Markov dependency to find cell correspondences between consecutive frames. To perform track linking and to identify the cell states in the time-lapse sequence we find the solution that minimizes a global cost function defined over the set of all cell tracks by a heuristic approach. We represent cell tracks by an acyclic graph that we use to visualize the lineage tree. We use the region centroids to display the cell trajectories. Finally, we compute morphological, motility, diffusivity, and velocity measures using the time-lapse images, the cell label maps, and the tracking data. We validate the cell segmentation and tracking stages both individually and as a joint system against reference standards that were manually generated. The image sequences and reference standards were obtained from a public database used for international cell tracking competitions. The validation measures quantify the region delineation accuracy by comparing levels of region overlapping and they calculate the cell tracking accuracy by comparison of acyclic graphs constructed from the cell tracks. The proposed techniques produce promising accuracy rates in comparison to the state-of-the-art. The ST-Diff-TCV segmentation technique yields an average DICE score of 89% over all 12 time-lapse image sequences. The automated tracking method using reference masks as input produces an average TRA score of 99%, which validates the tracking stage, and the fully automated system using both the proposed ST-Diff-TCV segmentation and tracking techniques produces an average of 89% with the 8 out of 12 sequences producing TRA > 91%.Item Open Access Developmental perturbation in early embryogenesis persist to impair neuronal function in adultsMersha, Mahlet D.Animal body plans tend to display external symmetry; however, their internal organs can be anatomically and/or functionally asymmetrical. Visceral organs such as liver, heart, and pancreas show clear anatomical asymmetry in a bilateral fashion. The right and left cerebral hemispheres are functionally asymmetric and small deviations have been correlated with pathologies such as schizophrenia and bipolar disorders. The bilateral asymmetry is genetically and developmentally defined as a third axis as are the other two axes: anterior/posterior and dorsal/ventral. The lab model Caenorhabditis elegans is particularly suited to study left/right (L/R) asymmetry. Like most other animals, C. elegans shows predominantly bilaterally symmetric external anatomy, but clear bilateral asymmetry in the viscera, a key feature being the placement of the anterior gonad towards the right. In addition to anatomical asymmetry certain neuronal pairs such as AWC-L and AWC-R also display functional asymmetry. The anatomic bilateral asymmetry is discernible during the initial cell divisions of the fertilized egg. Previous studies have suggested that PAR proteins along with Gα proteins associated with spindle positioning that play a role in anterior/posterior and dorsal-ventral are are likely to underlie the first symmetry–breaking step as well. The absence of gpa-16, a Gα protein, has been shown to yield up to 50% sinistral worms. On the contrary, wild type N2 animals invariably lead to dextral embryos. We have investigated the direct effects of disrupted asymmetry on embryonic lethality and adult behavior. Here, we show that the absence of gpa-16 results in not only sinistral embryos but also randomly dividing embryos. Surviving adults with the gpa-16 mutation are impaired in both, associative and non-associative learning. We are examining if the reversed asymmetry manifests its functional effects on behavior due to potentially atypical neuronal circuitry and looking at synaptic connectivity of gpa-16 mutants with the goal of unraveling anatomically atypical circuits.Item Open Access An Evaluation of a Northern Bobwhite (Colinus virginianus) Parent-reared Release in South CarolinaHaley, RyanNorthern bobwhites (Colinus virginianus) have experienced large, range-wide declines mainly attributed to the loss of early-successional habitat. Bobwhite population recovery is predicated on sound habitat management. Even when adequate habitat exists, low bobwhite densities and limited dispersal capabilities may limit population recovery. Restocking techniques, including release of pen-reared birds, wild bobwhite translocation, and the use of wild-strained, parent-reared captive-raised bobwhites have been explored as surrogates to natural recolonization. In this study, I evaluated survival and reproduction of parent-reared bobwhites, compared to resident bobwhites, on a private property in South Carolina from April 2009-April 2013. I used a sequential modeling approach to evaluate adult survival and nest survival using Program MARK. Bobwhite survival was best explained by temporal (annual and weekly) effects and group (parent-reared vs. resident) effects. Weekly bobwhite survival for both parent-reared and resident bobwhites was too low to produce a stable population. Parent-reared bobwhite survival was lower than resident bobwhites during the first 3 weeks post-release but similar during later weeks. Parent-reared bobwhites released in August had higher survival (S = 0.884, 95% CI = 0.862, 0.903) than birds released in early fall (S = 0.707, 95% CI = 0.621, 0.782). Nest survival and other reproductive parameters for parent-reared and resident bobwhite were similar. The viability of the parent-reared release system as a restocking technique is limited as currently constructed and future modification is needed if it is to produce a viable bobwhite populationItem Open Access Impact of authentic leadership practices of principals and the associated levels of teachers’ trustCropper, DeeaThe purpose of this comparative case analysis was to examine the authentic leadership practices of school leaders and the associated levels of teachers’ trust within the school setting. The level of trust between teachers and school administrators affects the school as a whole. “Without trust,” as Blase and Blase (2001) write, “a school cannot improve and grow into the rich, nurturing micro-society needed by children and adults alike” (p.25). Empirical qualitative literature that focuses on the leadership practices of school leaders and its effect on trust of teachers warrants further investigation. The comparative analysis addressed the following: an examination of authentic leadership, leadership practices in the public school system, the leadership practices that build trust among teachers and implications for administrators and building leaders. The findings suggest that when a principal was open, influential, articulate and credible, trust was created.Item Open Access Bat Activity on Golf Courses in DelawareWallrichs, MeganDue to landscape modifications and chemical use, golf courses have earned a negative reputation among some environmental groups, but their park-like landscapes may offer habitat for some wildlife species, especially over other land use types. In this study, I monitored bat activity using ultrasonic acoustic detectors in different small-scale habitats found on golf courses on the Delmarva Peninsula. My objective was to evaluate if and how bats are using course landscapes. I found differences in overall activity levels at the habitat level but not on different golf courses. Areas with closed canopy and open understory that were managed had significantly higher activity than other four habitats that reflected more natural habitats (open grass, dense canopy forest fragment, and open canopy forest fragment). The open understory managed areas also had significantly higher foraging activity than the other four habitats. Six of the eight bat species thought to occur on the Delmarva Peninsula were recorded, but Eptesicus fuscus and Lasiurus borealis dominated bat activity across all golf courses and habitats and had highest activity in open understory managed habitat. These findings indicate that bats are using golf courses on the Peninsula regularly as flyways and foraging grounds, and even substantially disturbed areas are used extensively. This study adds to the growing body of literature that positive partnerships can be created between wildlife and golf courses.Item Open Access In vitro Assessment of Phytoconstituents, Efficacy and Cytotoxicity of Extracts from Medicinal Plants on Prostate Cancer C4-2 CellsAsuzu, Peace ChiamakaPhenolic compounds are products of secondary plant metabolism known for their biological activity including their antimicrobial, antioxidant, analgesic, stimulant, anti-carcinogenic, and aphrodisiac properties. The main objective of this study was to assess the content and properties of bioactive phytochemicals in the extracts of Prunus africana, Pausinystalia yohimbe, Moringa oleifera, Momordica charantia and Orthero spp and determine their potency/cytotoxic effects. Total phenolics (TPC), carotenoids, anthocyanins, and flavonoids and their antioxidant properties in water, ethanol, methanol, acetone, and dichloromethane extracts of the different plant parts of these five plants were measured using the Folin-Ciocalteu, 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity (DPPH), ferric reducing antioxidant power (FRAP), and 2,2′-Azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) radical scavenging (ABTS) assays. For most of the plant samples, extraction yields were highest in ethanol or methanol extraction solvents. The highest total phenolic content (1397.33 mg GAE/g) was seen in the methanol extract of P. africana bark from Cameroon, while the acetone extract of M. charantia leaves yielded the highest total flavonoid content (217.33 mg RU/g). The FRAP values in this study ranged from 7.09 in the DCM extract of P. africana bark (Kenya) to 131.57 mM Fe2+/g in ACE extract of M. charantia leaf. The EC50 values for the acetone and methanol extracts of P. africana bark (Cameroon), methanol and ethanol extracts of P. yohimbe leaf and the methanol extract of P. yohimbe root were comparable to ascorbic acid (0.18 mg/mL). TPC showed a strong positive correlation with TFC of acetone extracts of P. yohimbe and Orthero roots, FRAP of ethanol and methanol extracts of P. africana (Cameroon) root, acetone and methanol extracts of P. africana (Cameroon) leaf, methanol extracts of P. yohimbe leaf, M. charantia leaf and the TEAC of P. africana (Cameroon) bark water extract, ethanol extracts of P. yohimbe leaf and Orthero root. Using high performance liquid chromatography (HPLC), seven phenolic acids, namely methyl 4-hydroxybenzoate, protocatechuic acid ethyl ester, trans-sinapic acid, vanillic acid, trans-ferulic acid, p-coumaric acid and caffeic acid were isolated from nine extracts of P. africana and P. yohimbe. The most abundant phenolic acids were vanillic acid (116.41 mg/g dry extract in methanol extract of P. yohimbe leaf) and trans-sinapic acid (102.22 mg/g dry extract in water extract of P. africana bark). On gas chromatographic phytosterol analysis, stigmasterol, β-sitosterol and campesterol were present in all plant parts of P. africana and P. yohimbe except for P. africana root and bark, where campesterol was not detected. β-sitosterol showed the highest concentration and variation between plant parts, ranging from 0.55-2.26 in the bark and leaf and 0.35-0.46 mg/g in the root and leaf of P. africana and P. yohimbe, respectively. Using different concentrations of P. africana extracts, prostate cancer C4-2 cells, a hormonally insensitive subline of LNCaP cells, were treated in a proliferation assay. A concentration dependent inhibition of cell growth in cells treated with P. africana bark and root extracts was present from days 1 through 3 of incubation, with the methanol extract of the bark showing the strongest effect. Compared to other plant parts, leaf extracts were significantly less cytotoxic at the same concentrations. All plant part extracts contained significant amounts of phenolic compounds and pigments with potent antioxidant activity comparable to that of ascorbic acid, in the case of P. africana, demonstrated in vitro cytotoxicity.Item Open Access Numerical solutions to paraxial wave equationsMross, Colby PierceIn this thesis, we apply various numerical methods to solve ordinary differential equations and the paraxial wave equation. The numerical methods we applied to solving paraxial wave equation are the 4th order Runge Kutta method, the Crank-Nicolson method, the Leapfrog Crank-Nicolson method, and the splitting spectrum method. The advantage of the explicit RK4 method is the high order accuracy in time. We perform detailed comparison between these numerical methods. The paraxial wave equation is derived from Maxwell's equation and we focus on the case of cubic Kerr nonlinearity presents, which is applied to study optical pulse propagation in nonlinear Kerr media. The Leapfrog Crank-Nicolson method, being an implicit method, is the most cost efficient method and when choosing small step sizes can be the most accurate when applied to paraxial wave equations.Item Open Access Magnetic Noise due to Interactions Between Bulk Impurities and Electrons in Nitrogen Vacancy Center DiamondsBarrios, BruceNitrogen vacancy centers (NV) diamonds present great interest as robust atomic-scale magnetic field sensors. One of the serious problems of NV-center diamond devices is electric and magnetic field noise. The noise can be verified by the optically detected magnetic resonance (ODMR) line-broadening; the noise reduce sensitivity of the devices. In this work we theoretically study the magnetic field noise caused by the magnetic dipole-dipole interactions between the bulk impurities of 13C, 14N and the electron in the NV-center. We use the cluster correlation expansion method to calculate the magnetic field fluctuations, and then, obtain the noise spectrum. The noise spectra is greater at lower frequencies but decrease at higher frequencies.Item Open Access Improving identification of subtle changes in wide-area sensing through dynamic zoomGreen, Michael AlvinThe past decade has seen an abundance of applications that utilize sensors to collect data. One such example is a gigapixel image, which combines a multitude of high-quality images into a panorama capable of viewing hundreds of acres. The resulting datasets can be quite large, making analysis time consuming and resource intensive. Moreover, coverage of such broad environments can mean numerous sensor feeds to which one must attend. A suitable approach for analysis and sense-making of such data is to focus on "interesting" samples of data, namely regions of interest, or ROI. ROIs are especially useful in wide-area sensing situations that return datasets that are largely similar from one instance to the next, but also possess small differences. Identifying subtle changes is relevant to certain scenarios in surveillance, such as the evidence of human activity. Several ROI detection techniques exist in the research literature. My work focuses on ROI detection tuned to subtle differences for images at varying zoom levels. My thesis consists of developing a method that identifies regions of interest for subtle changes in images. In this pursuit, my contributions will address key questions including the characterization of image information dynamics through introduction of dynamic zoom, the definition and measurement of subtlety, and an approach for scoring and selecting ROIs. This work will provide an automated attention mechanism for zoomed images, but is also applicable to domains include satellite imagery and cyber security.Item Open Access Enzyme-assisted aqueous extraction of Njangsa (Ricinidendron heudelotti) seed oilArrey, Immaculate TabeSolvent extraction methods are widely used industrially to obtain oil from plant seeds, mostly due to their high efficiencies (90-98% w/w yield). However, consideration is being given to solvent-free extraction methods due to the growing concern that residual solvent in oil could pose significant health and environmental risks. As such, enzymatic extraction methods are receiving considerable interest in the oil industry due to their high specificity. Certain enzymes such as: hemicellulase, protease, pectinase and amylase are known to hydrolyze and degrade the cell wall of oilseeds, which significantly increases oil yield and quality upon extraction. Therefore, the aim of this study was to explore the effects of these four different enzymes on Njangsa (Ricinodendron heudeulotti) seed. A control without any enzyme was run in tadem. These treatments were compared to solvent-extraction using hexane. The percent yield of the enzyme-assisted extraction (28.37 - 36.0%) were significantly (p < 0.05) higher than that of the control (19.09%) but, lower than the hexane extraction (46.40%). Quality indices of Njangsa seed oil (NSO) such as: acid, peroxide, saponification, thiobarbituric acid, para-anisidine and free fatty acid values of the enzyme-assisted extraction samples were found to be significantly (p < 0.05) lower than the solvent extraction samples. Predominant fatty acids of NSO were alpha-eleostearic acid (α- ESA), linoleic, stearic, and oleic. NSO had a high polyunsaturated fatty acid content. The use of enzymes in Njangsa seed extraction were able to improve the quality parameters of Njangsa oil.Item Open Access The effect of catholic identity on college student perception of missionMalcolm, Jacquelyn LorraineThe purpose of this comparative case study analysis was to examine the effect of Catholic identity on college student perception of mission. Much of the uncertainty of Catholic identity evolves around students’ experiences of Catholics at Catholic institutions (King, 2014). Despite the correlations that have been made between institutional mission and student outcomes, organizational behavior, and strategic management, remarkably there are few reliable and valid measures in existence that directly evaluate stakeholders’ perceptions of an institution’s mission (Ferrari et al., 2004 and Ferrari et al., 2006). The comparative case study analysis address the following: Catholic identity and its effect on college students’ perception on the level of Catholicity as shown and practiced through mission. This research study will also act as a framework for future research studies on Catholic identity as it relates to specific student populations.Item Open Access The study of bacterial communities in catfish (ictalurus punctatus) during storageAccumanno, GinaFish is a lean source of protein and abundant in vitamins and minerals. Unfortunately, fresh fish deteriorates rapidly mainly due to microbial spoilage. With consumers’ health concerns about using harsh chemical preservatives, natural antimicrobials would be a safer, alternative solution to prevent microbial spoilage. Metagenomics refers to investigating microbial communities from foods, environmental samples etc. and understanding how they interact with one another. Bacterial taxonomy, as a whole can be classified using high throughput sequencing platforms. In this study a commercial store-bought catfish and a pond-raised catfish were treated individually with three natural preservatives. From the catfish samples under refrigerated storage, DNA libraries were sequenced on the Illumina MiSeq platform. Of the 3 treatments, N#1 showed the most significant bacteria reduction at the midpoint (99%) in the store-bought fish and in the pond-raised fish in the late phase (>99%). Pseudomonas dominated the other bacteria in early phase for all sample treatments in the store-bought fish but was suppressed by the N#1 in middle phase which allowed for more diversity. In the pond-raised fish, Pseudomonas also dominated other bacteria in the sample treatments for the middle and late phases but never became the dominant bacterial species for the pond-raised N#1 samples which allowed for greater diversity overall. This knowledge can suggest effective natural preservative treatments to extend the shelf-life of fishery products.Item Open Access An examination of recreational angling for sharks in Delaware watersJohnson, SymoneRecreational angling targeting prohibited shark species (e.g. Sand Tiger (Carcharias taurus) and Sandbar (Carcharhinus plumbeus) Sharks) has increased in Delaware, raising concerns about the population status of these species. In an attempt to help address these concerns, my thesis had two objectives: to better understand recreational anglers’ perceptions of and interactions with prohibited sharks; and to explore gear modifications that result in minimizing harm to shark species caught during recreational angling. To achieve my first objective, I developed an angler survey with the goals of: 1) improving our understanding of threats to sharks, 2) identifying potential solutions to threats of shark conservation, and 3) improving fisheries management of sharks through reduced injury or mortality. The survey highlighted the need for improved accuracy in species identification and compliancy with best angling practices and/or regulations as threats to shark conservation. My findings suggest that resource managers may modify their approaches to reduce injury or mortality of sharks through increased angler education and training, K-12 education, social media campaigns, and increased enforcement. Building upon this, I examined the efficacy of experimental (blocker) longline gangions compared to control gangions for reducing damage to individual Sand Tiger and Sandbar Sharks during capture events. Over a three year period (2012-2014) comprising of 153 longline sets, I landed 493 Sand Tiger and 240 Sandbar Sharks. Overall catch rates of Sand Tigers (p = 0.024) and Sandbar Sharks (p = 0.013) were reduced on the experimental gangions. Gear type had a marked impact on hooking location (p = 0.003) for Sand Tigers as the overwhelming majority (96.3%) of gut hooked Sand Tiger individuals were encountered on control gangions. The use of blocker gangions shows much promise in minimizing risk of injury for Sand Tigers captured during longline surveys. In the case of Sandbar Sharks, there were no incidents of gut hooking in the entire study suggesting that the risk of injury from gut hooking is minimal for the species. The marked decline in gut hooking rates with Sand Tigers noted with the use of the experimental gangions underscores its potential use as a tool to reduce injury risk and to improve post-release survival prospects. It is well understood that a healthy marine environment provides direct and indirect economic awards and healthy shark populations are a key point in these environments. I hope my efforts to provide insights on angling preferences and practices in Delaware, as well as a potential tool for use in the angling community, will help foster increased recovery prospects for these important species.Item Open Access Characterization of strawberry (fragaria ananassa) by genotyping and phenotypingBiswas, AnjuStrawberry is an important fruit crop for its nutritional value and is known to have a higher amount of antioxidants. Consuming strawberries can increase dietary antioxidants. Antioxidants in strawberry can act against cardiovascular diseases, cancer, and other health issues. Recently, use of molecular markers is becoming popular in strawberry breeding programs as well as in genotyping of existing varieties. Genotyping is the process of determining genetic differences among individual plants and can be readily applied to identify genetic diversity among the germplasm. Simple sequence repeat (SSR) markers present in every living organism. Majority of the SSR markers are used for genotyping includes cultivar identification, genetic diversity analysis, taxonomic analysis, marker-assisted breeding, and cloning. It is easier to identify a trait of interest in any genotype if known SSR markers are available. Cultivated strawberries have a wide range of SSR markers available which permits to detect polymorphism of closely related genotypes as the genome of strawberries has been sequenced. In this study, we genotyped thirty-three strawberry accessions utilizing thirty-five SSR markers and phenotyped by observing leaf total antioxidant (TA) content, leaf shape, leaf trichome density and petiole size. DNA extraction, PCR, and SSR analysis were done for genotyping. We identified two distinct genetic groups from those genotypes, one group is alpine (wild or woody) type strawberry and another group is the cultivated type. In this study, we identified 120 alleles with an average of 3.43 alleles per locus. The genetic polymorphism ranged from 0.1461 for the marker ARSFL_9 to 1.6635 for the marker FG1a/b. All thirty-three accessions were grouped into clusters based on the genetic diversity analysis and found that grouping them into three clusters was provided the maximum genetic diversity. The cluster three contained more diverse genotypes among those. Leaf total antioxidant content was measured in Trolox equivalent amounts by colorimetric assays. The highest antioxidant containing genotypes were Earliglow, Wendy, Elan hybrid, Clancy, and Record. Spectrophotometer and high-resolution camera were used for phenotyping. We classified all genotypes into five groups according to the leaf shape and three groups according to the leaf trichome density and leaf petiole size. From the association, the two genotypes named Clancy and Elan hybrid contained more total antioxidant content with high trichome density. Strawberry breeding programs can utilize information from this research during cultivar development and authentication of genotypes.Item Open Access Monitoring of vibrio species in oysters crassostrea virginica and seawater of Delaware bay and molecular characterization of vibrio parahaemolyticusAlmuhaideb, EsamABSTRACT Delaware Bay is the prime oystering ground in Delaware. Oysters naturally inhabit marine environments and, as filter-feeding mollusks, they tend to accumulate different microorganisms from seawater during their filtration process. Most of the illnesses caused by the consumption of raw and undercooked oysters are strongly associated with the oysters contaminated with Vibrio spp. Vibrio spp. are Gram-negative pathogenic bacteria from the family Vibrionaceae that negatively impact aquatic systems and human health. This study aimed to identify and differentiate Vibrio spp. in oyster and seawater samples from the Delaware Bay using CHROMagarᵀᴹ Vibrio medium which provides the means for easy differentiation of Vibrio parahaemolyticus, Vibrio vulnificus, Vibrio cholerae, and Vibrio alginolyticus based on the colony color. Pathogenic Vibrio parahaemolyticus was characterized using conventional PCR which was applied for the identification of total and pathogenic V. parahaemolyticus by screening the species-specific tlh gene, and the virulent tdh, trh, toxR, and vpm genes. Vibrio spp. were differentiated and isolated, and total and pathogenic V. parahaemolyticus from oyster and seawater samples were identified. Oysters and seawater samples were collected once a month from June through October 2016, from Bowers Beach, and Lewes, Broadkill in Delaware Bay. A third site, Slaughter Beach, was added to this study from August through October 2016. Physico-chemical water quality parameters recoded on-site during samples collection include water and air temperature, salinity, pH, dissolved oxygen, turbidity, chlorophyll a, depth, conductivity, weather, wind direction, wind speed, and tide. Oyster and seawater samples were serially diluted up to (10⁻⁶), and 100 µL of each dilution from each sample were spread plated on CHROMagarᵀᴹ Vibrio medium. V. parahaemolyticus, V. vulnificus/V. cholerae, and V. alginolyticus colonies were identified based on color development (mauve, green/blue, and colorless, respectively). Average Vibrio spp. in oyster ranged from <10 CFU g-1 (non-detectable) to 2.8×104 CFU g-1, while the average of Vibrio spp. in seawater samples ranged from 1.7×10 CFU mL-1 to 4.47×103 CFU mL-1. More Vibrio colony forming units were observed during the warmer months (June through September). As anticipated, the total colony forming units of Vibrio spp. were proportional in both oyster and seawater samples. The multiple regression model indicated a significant positive relationship between Vibrio spp. and V. parahaemolyticus Log10 CFUs and water temperature, (p < 0.05). The one-way ANOVA analysis showed no statistical significant association between Vibrio spp. Log10 CFUs and the sample type, oysters and seawater (p > 0.05). A total of 165 bacterial isolates of Vibrio parahaemolyticus (mauve colonies) from oyster and seawater samples were examined for the presence of tlh, tdh, trh, toxR, and vpm genetic markers. Only 19% of the samples tested were positive for tdh and 24% were positive for trh while 83%, 65.5%, and 67% of the samples were positive for tlh, toxR, and vpm, respectively. This confirmed the specificity of tlh gene for V. parahaemolyticus species. Screening for tdh and trh genes is not sufficient for the surveillance of pathogenic or potential pathogenic V. parahaemolyticus but the reliability of toxR and vpm as gene markers is notably higher.Item Open Access A case study analysis: assessing the impact of leadership practices and training on student achievement in special education programsBecton, Veronica L.ABSTRACT Special education has mystified and alarmed educators, parents, politicians and the government for decades. Mediocre special education programs, staggering test scores and limited progress towards meeting standards have caused the federal government to require states to implement several mandates. Despite the federal and state mandates the problem has not been resolved. If anything, the problem has been acerbated. School leaders have been inundated with new responsibilities placing added pressure on themselves, educators and students. All while students with disabilities continue to struggle to meet reading and math standards. The purpose of this study was to examine the leadership style and formal training of special education school leaders to determine the impact on the academic achievement of students with special needs. A single case study from Denver, and two case studies from Florida were analyzed for this case study analysis. Results from the study showed an increasing need to improve administrative leadership certification programs to better prepare school leaders to evaluate and assess the needs of special education programs. The results also revealed that when school leaders have the education and training to lead effective inclusive schools, student achievement improves.Item Open Access Regulation of gene expression by the CD44-Intracytoplasmic domain (CD44-ICD)Shelton, Alexis S.CD44 is a major cell membrane hyaluronan receptor and cell adhesion glycoprotein. It is involved in multiple cellular processes including cell migration and invasion, apoptosis, stemness and cell proliferation. It exists in a variety of isoforms mainly due to the alternative splicing of ten of its 20 exons and posttranslational modifications. CD44 also undergoes proteolytic cleavages that generate the CD44 intracytoplasmic domain (CD44-ICD). The CD44- ICD is translocated to the nucleus where it can regulate gene expression. The CD44-ICD- dependent regulation of gene expression is likely to be mediated by protein-protein interactions (PPI) with factors of the transcriptional machinery, which makes of the CD44-ICD a transcriptional co-regulator. However, the existence of the CD44-ICD response element (CIRE) and its reported binding to it makes of the CD44-ICD a transcription factor. We hypothesize that the CD44-ICD is a novel transcriptional regulator with properties of a co-regulator and a transcription factor. To test this hypothesis we carried out PPI assays such as proximity ligation assays (PLA) and plate array PPI assays. We also analyzed the expression of genes related with CD44-associated cellular events such as apoptosis, oxidative stress and stemness using proteome profiler assays and transcription factor activation plate arrays. PLA data showed that the CD44- ICD interacts with the transcription factor Runx2 in the nucleus as well as in the cytoplasm. We also found that the CD44-ICD interacts with more transcription factors. The expression of CD44 in MCF-7 cells, which is expected to generate the CD44-ICD, inhibited the expression of Nrf2, caspase 3 and E-cadherin, important genes in oxidative stress, apoptosis and stemness, respectively. The inhibition of Nrf2 in MCF-7/CD44 cells, promoted a higher sensitivity to oxidative stress caused by hydrogen peroxide compared to MCF-7 cells. Altogether, these data iii supports that CD44 can act as a regulator of gene expression and that this regulation is in part via its intracytoplasmic domain once released into the cytoplasm and nucleus. The CD44-ICD appears to be able to act as a co-activator as well as a co-repressor. Because the CD44-ICD size of only 72 residues, the CIRE sequence to which it can bind is unusual. This type of protein- DNA interaction is usually associated with larger DNA-binding proteins such as bona fide transcription factors. The dual capacity of the CD44-ICD to interact with proteins of the transcriptional machinery as well as to interact with its own response element on promoter sequences, might place the CD44-ICD in a novel category of transcriptional regulators.Item Open Access A Study on the Numerical and Analytical Solutions of Complex-Variable Partial Differential EquationsMoore, Matthew NeilIn this work, we consider the analogue of a real-variable partial differential equation. In comparison to what has already been thoroughly investigated, recall the non-linear Schrodinger equation (NLSE). The NLSE, which is used in determining the wave equation for quantum particles, is a real-variable PDE with complex coefficients. Instead, we consider equations where both the function $\omega$ and its independent variable $z$ belong to the complex plane. We approach the complex problem by an intuitive approach of treating a one-complex variable differential equation as a two-real variable partial differential equation by analyzing the real and imaginary parts of both $\omega$ and $z$. We investigate thoroughly the first-order complex PDE case and prove the existence and uniqueness theorem for these types of equations. We also investigate the analytical solutions by considering the complex-variable Laplace transform, which can be thought of in parallel as a two-variable Laplace transform with in $\mathbb{R}^2$. Upon completion of the first-order case, we consider the higher order complex-variable PDE. We discuss both the direct way of solving higher-order equations via systems of real-variable PDE’s and also via first-order systems of complex-variable PDE’s, in which we implement the methods of the previous topics. As a direct consequence of the higher-order differential equation solution method, we also discuss an alternative method of evaluating complex contour integrals via a real-variable partial differential equation evaluation. To conclude, we consider the time-dependent complex variable PDE analogues of the advection and wave equations, we briefly discuss multi-complex variable PDE’s and methods that we plan to investigate in the near future.