Viability of Stylosanthes Seeds as Affected by Storage Duration

Tropical legumes such as members of the genus Stylosanthes (sty lo) contribute to the improvement of pastures in the tropics and sub-tropics. Stylosanthes is usually established from seed. In Florida, seed of Stylosanthes has to be produced and col­lected before the onset of the winter since occasional frosts can damage seed-bearing vegetation. Therefore, early maturing Stylosanthes varieties have been developed. In stylo seed collections maintained for breeding or seed exchange purposes, maintenances of seed viability is critical. New pests or new diseases may require a renewed screening of stored accessions. It is important, then, that the seed source of this species be renewed. It is not known about how long seed of stylo remains viable ��-hen stored under ambient temperature and humidity cond- 1tlons. Legumes seeds in general (Toole, 1986) and stylo in particular (Mott, 1969), have hard impermeable seedcoats. Consequently, they may not be as greatly affected by moisture conditions as seed of other species. Therefore, older seed sam­ples of Stylosanthes may germinate after years of storage. Seed viability can be maintained by reducing moisture content of seed and by storage at low temperature. However, moisture removal and low storage facilities may not be available in many areas where stylo is being grown and stored. The purpose of these studies was to test the viability of Stylosanthes species after seed had been stored for several years under ambient temperature and humidity conditions. The goal was to estimate the maximum storage time which could still result in satisfactory germination

Effect of Frost on Panicle Production in Dactylis glomerata

The average seed yield of cocksfoot in Finland is small. The panicle formation has often been poor although the stand has otherwise been in good condition. In the present study the importance of early summer frost on the failure of panicle for­mation in cocksfoot was studied. The cold tolerance of cocks­foot has been observed to be poor compared to other perennial grasses (Gudleifsson et al., 1986). The sensitivity of cocksfoot to frost during the growing season was observed in the exper­iment of Nikolaevskaya (1973) where a frost treatment at flowering stage of cocksfoot completely destroyed the caryopses. Results of experiments conducted at the earlier stage of cocksfoot panicle development are probably not available. Frost treatments at the late panicle formation stage in Poa pratensis significantly decreased the number of panicles produced and the freezing injury was specific for the primordia flower (Heide, 1980)

Plant Improvement using Endophytic Fungi

Endophytic fungi which grow intercellularly in many species of grasses have been a scientific curiosity for almost a century. The mycelium of many of these fungi never emerges from the plant and the fungus is disseminated by way of hyphae in the seed. Other endophytes such as Epichloe typhina form a myce­lial weft around the developing inflorescences thus preventing seed formation. Grasses infected with endophytes usually appear healthy and the presence of the fungus can only be detected by examining tissues from leaf, sheath, culms and seed for fungal mycelium. The economic importance of these fungi was first discovered by Bacon et al., (1977) when they showed that the presence of the endophyte Acremonium coenophialum in tall fescue ( Festuca arundinacea) was associated with fescue toxicosis in cattle. A similar association between the endophyte A. lolii in perennial rye grass ( Lolium perenne) and the disorder of anim­als known as ryegrass staggers was demonstrated by Fletcher and Harvey (1981). Although these fungi can be harmful to grazing animals their presence in grasses can have beneficial effects for the plant. Endophyte-infected grasses are resistant to predation from some insects, produce more herbage (Siegel et al., 1987), are less affected by drought stress (West et al., 1988) and they are more resistant to some fungal diseases (Koshino et al., 1987) and to nematodes (West et al., 1988) than are endophyte-free grasses. The toxin thought responsible for causing ryegrass staggers is lotitrem (Gallagher et al., 1984) and the compound which deters insects from feeding is peramine (Rowan et al., 1986). The factors which influence plant growth, tolerance to drought, and resistance to fungi and nematodes in grasses infected with Acremonium endophytes are not yet known. The major advantage of endophyte infection in ryegrass is the toxicity of the grass to animals. This paper describes the search for a strain of A. lolii that does not induce the pro­duction of lolitrem but still confers on the plant the many advantages of endophyte infection

The Breeding of Pasture Varieties of Alfalfa (Medicago sativa)

The work of developing new pasture varieties of alfalfa has been conducted in the All-Union Fodder Research Institute from 1975 onwards. The pasture varieties must be persistent under grazing, and must have a high competitive ability in mix­tures with grasses : meadow fescue, timothy and others

INVESTIGATING THE FITS AND FUNCTIONALITY OF THE COMMUNITY COLLEGE SURVEY OF STUDENT ENGAGEMENT USING RASCH MODELING

Student engagement is a central variable in higher education research as it influences academic achievement, retention, and the development of problem-solving skills. The Community College Survey of Student Engagement (CCSSE) is a vital tool for assessing student engagement in community colleges. Previous validation studies were mainly conducted in the mid-to-late 2000s and have used Classical Test Theory frameworks despite the known limitations of this approach. The present study seeks to evaluate the psychometric properties of the CCSSE survey using a Rasch Analysis framework. The two CCSSE datasets were obtained from the Center for Community College Student Engagement at The University of Texas at Austin. These datasets include responses from the 2019 and 2023 CCSSE cohort member colleges. Two research questions: a) To what extent do the 2019 and 2023 CCSSE survey benchmarks align with the assumptions and expectations of the Rasch model, considering issues of unidimensionality and fit? and b) How do racking and anchoring methods compare in measuring changes in item difficulty parameters of the CCSSE survey, specifically between the 2019 and 2023 survey administrations? were used to explore the fits and functionality of the survey. These research questions were addressed using Rasch analysis to examine the psychometric properties of the 2019 and 2023 CCSSE benchmarks, determining how well the items fit the assumptions of the Rasch model. Additionally, racking and anchoring techniques were applied to compare their techniques in measuring changes in item difficulty parameters over time, identifying items that exhibited significant shifts in difficulty between the 2019 and 2023 survey administrations. The Principal Component Analysis of Rasch residuals suggests that three of the five benchmarks demonstrate unidimensionality, while two show multidimensional traits. The Pearson and Disattenuated correlation coefficients further support this, indicating that two benchmarks are likely multidimensional, while three remain unidimensional. However, after examining the wording of the items that could cause potential dimensionality issues, this study concluded that all five survey benchmarks are unidimensional; however, some items may need to be revisited and reworded. The survey benchmarks showed strong item reliability and separation but weaker person reliability and separation. Infit and outfit MNSQ statistics revealed acceptable values for nearly all items, supporting the validity of the survey. Wright\u27s maps for the survey benchmarks showed a well-distributed item spread, suggesting that the survey is well-targeted to the student. However, the gaps at both ends of the Wright maps suggest that the items may not capture the range of student engagement traits in each benchmark. The anchoring and racking analyses revealed that the difficulty of most items remained stable between the two survey administrations. Overall, this study found that the CCSSE survey can be effectively used to assess various aspects of student engagement

LIVING WITH FLYING COLORS: ASSOCIATIONS AMONG LGBTQ+ IDENTITY, RELIGIOSITY, SPIRITUALITY, COMMUNITY, AND OVERALL WELL-BEING AMONG LGBTQ+ OLDER ADULTS

Experiences of discrimination and prejudice place LGBTQ+ individuals in older adulthood (i.e., 55 years old and older) at risk for poor overall well-being. This risk can be especially salient in the Southern and Midwestern U.S., where LGBTQ+ individuals enjoy fewer legal protections than in the Northeast and Western regions of the U.S. In defiance of these odds, LGBTQ+ individuals in older adulthood cultivate overall well-being through psychological-level constructs, like LGBTQ+ identity affirmation, and community-level constructs, LGBTQ+ community connection. Yet, little research has examined these avenues of strength among LGBTQ+ individuals in older adulthood. Guided by Iridescent Life Course Theory and the Flourish Index of overall well-being, the current study quantitatively investigated the impact of LGBTQ+ identity affirmation, LGBTQ+ community connection, religiosity, spirituality, and religious support on overall well-being among LGBTQ+ adults in older adulthood. Participants (N = 95) completed a 30-minute survey on their experiences with LGBTQ+ identity, the LGBTQ+ community, religiosity and spirituality, religious support, and well-being. The present study found that higher spirituality was associated with better overall well-being among the sample. Additionally, higher LGBTQ+ identity affirmation was associated with more LGBTQ+ community connection, and higher spirituality and religiosity were associated with more religious support. Findings from this study could inform cultural competency for LGBTQ+ individuals in older adulthood in healthcare settings, advocate for the needs of LGBTQ+ individuals in policy, and inform religious organizations of the unique religious and spiritual needs of LGBTQ+ individuals in older adulthood

Risks and Benefits of Prescription Psychostimulant Use among Older Adults

Prescription psychostimulant use among older adults has increased in recent years, raising important questions about their safety and efficacy in this population. Chapter 1 introduces this growing trend in the United States and highlights the need for research to inform safe prescribing practices. Chapter 2 presents a scoping review of the literature, identifying potential benefits of stimulants for on-label indications (e.g., attention-deficit/hyperactivity disorder, narcolepsy), as well as off-label uses including depression, apathy, fatigue, dementia, Parkinson’s disease, and post-stroke motor recovery. However, significant potential risks are also noted, particularly adverse cardiovascular events and neuropsychiatric complications. Chapter 3 explores the prevalence and sociodemographic characteristics of prescription stimulant use disorder among community-dwelling U.S. civilians, finding that very few individuals with stimulant use disorder were aged 65 or older. Chapter 4 uses a target trial emulation approach to compare the cardiovascular safety of amphetamines and methylphenidates—the two major stimulant classes—among older adults. Results show that methylphenidate initiation is associated with a higher risk of major adverse cardiovascular events (myocardial infarction, stroke/transient ischemic attack, ventricular arrhythmia, and mortality) compared to amphetamine initiation. Conclusions and implications for practice are discussed in Chapter 5

BACTERIA-ENGINEERED VESICLES FOR CANCER IMMUNOTHERAPY: FROM IMMUNOMODULATION IN VITRO TO ANTI-TUMOR EFFECTS IN MELANOMA MODELS

Bacterial vesicles hold immense potential in various biomedical fields. Among these, outer membrane vesicles (OMVs) produced by Gram-negative bacteria are the most extensively studied. While the exact mechanism of OMV production remains unclear, numerous environmental factors have been shown to influence both their yield and composition. In this study, we investigated the effect of three different antimicrobial families on OMV production by E. coli. Interestingly, antimicrobials within the same family did not provide the same effects on OMV yield, suggesting that OMV production may not directly correlate with the antimicrobial mechanism of action. OMVs have demonstrated tumor-inhibitory activity in multiple mouse tumor models. However, their potential toxicity poses a significant challenge, as OMVs have been shown to cause mortality in mice. To address this limitation, we developed bacteria-engineered vesicles (BEVs) as a safer alternative to OMVs. In vitro assays, BEVs effectively repolarized pro-tumor macrophages (M2) to the anti-tumor phenotype (M1) and promoted dendritic cell maturation. Additionally, BEVs were shown to serve as a versatile platform for antigen peptide display, with the displayed peptides not interfering with BEVs\u27 inherent immunomodulatory activity. We further evaluated the anti-tumor efficacy of BEVs in a B16F10 melanoma model. Intravenous administration of BEVs significantly inhibited tumor growth and elicited robust immune responses. Flow cytometry analysis of spleen and lymph node samples from BEV-treated mice revealed an anti-tumor immune response, including elevated M1/M2 macrophage ratio and an increased population of CD8+ T cells