Feather Reflectance Predicts Reproductive Success in Female Prothonotary Warblers

In many avian species, both females and males display colorful feather ornaments that in males are known to often signal individual quality and serve as the basis for mate choice. We do not know however, if the same applies for female birds. In this study, we investigated whether carotenoid content in female Prothonotary Warblers (Prothonotaria Citrea) feathers, a measure of feather quality, was correlated with annual reproductive success. Feathers from 130 female individuals over a period of four breeding seasons were collected and their reflectance was measured, along with data on annual reproductive success. We found a significant positive relationship between carotenoid content and number of young fledged, after accounting for the effect of nest initiation date, which is known to significantly influence annual reproductive success. We found that earlier and older females tend to fledge more young, but that all early arriving females are not the same. Among early breeders, the ones that go on to produce the greatest number of young have higher carotenoid content in their feathers. This same relationship was not found in later breeding females. This could indicate that males use female plumage as a signal to select higher quality females during the early portion of the breeding season when selection pressure is highest to choose a high quality mate.https://scholarscompass.vcu.edu/uresposters/1044/thumbnail.jp

Daimon

The following creative dissertation is a book of 57 poems

Spatial Analysis of Nest Productivity and Predation in Prothonotary Warblers

Generally, statistics are based off the assumption that observations are independent from each other in space. In larger ecological systems however, there can be spatial autocorrelation whereby data collected in nearby areas are not independent of one another which violates the assumption of most statistical tests. It is therefore becoming commonplace for ecological studies to study spatial autocorrelation to both eliminate error (accounting for a nuisance variable that could give false positives) and to better understand the spatial structure of their system of interest. Indeed, the mechanisms that lead to spatial autocorrelation are often associated with behaviors and/or intrinsic characteristics of our target species or community. In this study we investigated whether nest productivity and nest predation of the Prothonotary Warbler (Prothonotaria Citrea) were spatially autocorrelated at Deep Bottom Park along the lower James River, VA. Nest success and predation were measured at 66 different nest boxes over a period of four years (2009-2013). We found no spatial autocorrelation between these nest boxes when analyzing both reproductive success and nest predation events. This indicates that our observations are independent from each other in space, and spatial variables are not driving reproductive success or predation, rather individual bird quality is likely the main driver for these differences.https://scholarscompass.vcu.edu/uresposters/1171/thumbnail.jp

Can anyone be a scientist? Exploring the role of citizen science in coral reef research

Individuals lacking scientific training have made important contributions in many disciplines historically, but the role and value of public participation in modern professional research is controversial within the scientific community. Beneficially, citizen scientists provide a source of labor, a variety of skills, and capital. This link between the public and research serves as a bridge between science and education, creating a more environmentally informed populace. Through a survey of participants and scientists, this study evaluates and compares the role of both public and student-oriented citizen science (CS) in coral reef research, as well as professional scientists’ perception on citizen science’s place within the discipline. Results were analyzed using a quantitative Likert scale. Based on responses to a survey, we identified two major points that could improve CS programs: local program context should be related to coral reef studies worldwide, and the CS program should instill ways in which a participant can remain active in environmental activities beyond the program. Addressing these disconnects could optimize the effectiveness of citizen science programming, and resulting outreach within coral reef research

Sleep Challenges and Temperament Among Infants at Elevated Likelihood of Autism Spectrum Disorder

The current study used parent report in a prospective longitudinal design to examine the relationship between early sleep difficulties and temperament among infants with an older sibling diagnosed with ASD (EL-ASIB, n = 32), those born pre-term (EL-PT, n = 24) and those with no familial history of ASD (LL, n = 28) across the first year of life. At 3, 4, 6 and 12 months, caregivers completed the Short Form of the Infant Behavior Questionnaire-Revised (IBQ-R) (Putnam et al., 2014). To understand how sleep difficulties are related to temperament, a new scale of Sleep Challenges was created with items related to falling and staying asleep as had previously been done with the Very Short Form (Macduffie et al., 2020). Trajectories of sleep difficulties between EL-ASIB, EL-PT, and LL groups were determined with the use of linear mixed-effects models. In addition, associations between early sleep difficulties and IBQ-R scales were examined. From the analyses, it was determined that EL-ASIB infants in the sample experienced greater sleep challenges towards the end of their first year. Additionally, there were several nonsignificant negative associations between surgency/regulatory capacity and sleep challenges at 12 months. Lastly, EL-ASIBs with greater surgency had less sleep challenges than other EL-ASIBs. Findings of this study point to the possibility that infant siblings of autistic children may be at greater risk for sleep challenges and early predictors of sociability are related to temperamental challenges of falling and staying asleep. Additional research is needed to examine objective measures of sleep alongside temperamental measures and its relationship to clinical outcomes

Stiffness and Slip in Multi-dowel Timber Connections with Slotted-in Steel Plates

Large multi-dowel connections can provide the strength and ductility required for large, highly-loaded timber structures, but their slip under load is not well understood. This is an important gap in knowledge, because accumulated local displacements at connections represent a large part of the deformation of a timber structure. The empirical relationships used in design codes commonly scale a single-dowel stiffness by the number of dowels, so do not capture the dowel interaction effects of the multi-dowel connections used in larger structures. We present the results of an experimental test series, elastic model and probabilistic numerical analysis investigating the development of stiffness in multi-dowel timber connections with slotted-in steel plates. Novel test methods record the development of stiffness due to each individual connector to show that the stiffness of the complete connection is not proportional to the number of dowels. An elastic stress-function model shows that this is partly due to interaction of the stress field around the dowels. For the first time, this work quantitatively considers the influence of misalignment of dowels due to manufacturing tolerances, and it is shown that this may greatly reduce the overall stiffness of a multi-dowel connection. The test series is used to validate a probabilistic model of this misalignment for the stiffness of such a connection. The model incorporates the nonlinear stiffness and hole opening observed in single-dowel connections to predict the behaviour of the group. The study shows that the random misalignment of dowels in multi-dowel connections reduces the range of displacements over which the connection displays zero stiffness slightly, but that this zone is not eliminated as a result of irreversible hole opening under load, even for a connection with 35 dowels and three steel plates. We conclude that two parameters are important for the design of these connections: the unload-reload stiffness and the zero-stiffness region measured between the zero load intercept of the unload-reload linear fit. With these, a reasonable estimate can be made of the displacement at any serviceability load level in either tension or compression

The thorny issue of choosing outcome measures for aphasia therapy trials: A comparison of discourse and aphasia battery outcomes following Multi-modality and Constraint Induced aphasia therapy

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The impact of COVID-19 movement restrictions on physical activity in a low-income semi-rural population in Malaysia: a longitudinal study:a longitudinal study

BACKGROUND: The COVID-19 pandemic prompted movement restrictions in countries worldwide, impacting on physical activity (PA), a major non-communicable disease risk factor, and thus may have unintentional long-term health implications. In semi-rural areas of low-middle-income-countries (LMICs), where occupational activity is the main source of PA, changes in PA associated with COVID-19 restrictions are unknown. We investigated the impact of Movement Control Order (MCO) restrictions in a semi-rural region of Malaysia. METHODS: The South East Asia Community Observatory (SEACO) is a dynamic prospective community cohort. We contacted a random sample of 1007 adults (18+) who had previously provided PA data in 2018. We asked about PA during the MCO (March-May 2020) and at the time of interview (June 2020). RESULTS: During the MCO, PA reduced by a mean of 6.7 hours/week (95% confidence interval (CI) = 5.3, 8.0) compared to 2018, with the largest reductions among those in employment. By June, PA was 3.4 hours/week (95% CI = 2.0, 4.8) less than 2018, leaving 34% of adults currently inactive (20% in 2018). Reductions in occupational PA were not replaced with active travel or activity at home. Despite these observed reductions, most participants did not think the MCO had affected their PA. CONCLUSIONS: Movement restrictions are associated with lower PA lasting beyond the period of strict restrictions; such longer-term reductions in PA may have a detrimental impact on health. Future MCOs should encourage people to be active, but may additionally need targeted messaging for those who don’t necessarily realise they are at risk. In particular, policies developed in more affluent countries may not easily translate to LMICs