Divergence, gene flow, and the speciation continuum in trans-Beringian birds

Thesis (M.S.) University of Alaska Fairbanks, 2017Understanding the processes of divergence and speciation, particularly in the presence of gene flow, is key to understanding the generation of biodiversity. I investigated divergence and gene flow in nine lineages of birds with a trans-Beringian distribution, including pairs of populations, subspecies, and species, using loci containing ultraconserved elements (UCEs). I found that although these lineages spanned conditions from panmixia to fully biologically isolated species, they were not smoothly distributed across this continuum, but formed two discontinuous groups: relatively shallow splits with gene flow between Asian and North American populations, no fixed SNPs, and lower divergence; and relatively deeply split lineages with multiple fixed SNPs, higher divergence, and relatively low rates of gene flow. All eight lineages in which two populations were distinguishable shared the same divergence model, one with gene flow without a prolonged period of isolation. This was despite the diversity of lineages included that might not have responded in the same ways to the glacial-interglacial cycles of connection and isolation in Beringia. Together, these results highlight the role of gene flow in influencing divergence in these Beringian lineages. Sample size is a critical aspect of study design in population genomics research, yet few empirical studies have examined the impacts of small sample sizes. Using split-migration models optimized with full datasets, I subsampled the datasets from Chapter 1 at sequentially smaller sample sizes from full datasets of 6 - 8 diploid individuals per population and then compared parameter estimates and their variances. Effective population size parameters (ν) tended to be underestimated at low sample sizes (fewer than 3 diploid individuals per population), migration (m) was fairly reliably estimated until under 2 individuals per population, and no trend of over- or underestimation was found in either time since divergence (T) or Θ (4Nrefμ) . Lineages that were split above the population level (subspecies and species pairs) tended to have lower variance at smaller sample sizes than population-level splits, with many parameters reliably estimated at levels as low as 3 diploid individuals per population, whereas shallower splits (i.e., populations) often required at least 5 individuals per population for reliable demographic inferences. Although divergence levels may be unknown at the outset of study design, my results provide a framework for planning appropriate sampling, and for interpreting results if smaller sample sizes must be used

Introducing Allergenic Food into Infants\u27 Diets: Systematic Review

Purpose: The purpose of this systematic review was to explore the association between timing of introduction of potentially allergenic foods to infants and development of food allergies. Methods: CINAHL, Medline, PubMed, Science Direct, and Web of Science were searched using the terms solid food, complementary food, or infant feeding combined with allergy or hypersensitivity for articles published in English in 2000 or later. Inclusion criteria were 1) primary research articles with 2) a focus on association between introduction of complementary foods including potentially allergenic foods into diets of infants less than 12 months of age and development of food allergies. Articles were excluded if they were 1) not primary research, 2) about complementary foods only (without specifi city of allergenic foods), or 3) on allergic conditions other than food allergy (such as asthma or eczema). Results: The initial literature search yielded 533 articles; 14 articles met inclusion criteria. Level of evidence of each study was determined with the SORT criteria. Results found that delayed introduction of solid foods in general and allergenic foods in particular was not associated with decreased risk for allergic diseases among high and low-risk infants. Later introduction was associated with increased risk for allergy development. Clinical Implications: For infants at low risk for development of food allergies, providers should advise caregivers to introduce potentially allergenic foods with other solid foods between 4 and 6 months of age when children show an interest in eating solids. Infants at high risk for peanut allergy, should be evaluated by an allergy specialist prior to introduction of peanuts and work with providers to create an individualized plan for introduction of peanuts and other allergenic foods as needed

On Certiorari to the Ninth Circuit Court of Appeals : The Supreme Court\u27s Review of Ninth Circuit Cases During the October 2006 Term

Whether reversed, affirmed, vacated, or remanded, a review of the interaction between the two courts over twenty-two cases reveals several fundamental differences between the two courts on key issues. This Comment examines these differences by exploring twenty of those decisions and how they illustrate the relationship between the Ninth Circuit and Supreme Court. Part I examines the decisions that arose from the Supreme Court\u27s review of Ninth Circuit decisions. Part II ties these decisions and conclusions into a larger motif emerging between the Ninth Circuit and Supreme Court, and Part III ultimately concludes that the future is likely to continue to see disagreements between the two courts

Why are there so many birds in the tropics: using comparative approaches to investigate the confluence of landscape, ecology, and genome in the generation of Neotropical avian diversity

The Neotropics are home to an astonishing level of avian diversity, and thus naturally a focus for the study of the generation of biodiversity. Studies of tropical speciation often focus on large-scale landscape changes, such as the impacts of Pleistocene climate change, the formation of the isthmus of Panama, or the uplift of the Andes. However, the full scope of Neotropical avian diversity is not yet wholly understood, and increasing evidence suggests that other processes beyond these geographical factors contribute to speciation in tropical birds. Here, I examine genetic data, from mitochondrial markers to whole genomes, in a diverse array of Neotropical birds, to better understand the interplay between landscape, genome, and ecology in the development of reproductive isolation. In my first chapter, I use mitochondrial barcodes from over 2,000 birds to detect potential cryptic species across Panama. I find that species-level splits occur in 19% of sampled species, suggesting avian diversity in Panama is substantially underestimated. These disproportionately occurred in species with ecological characteristics associated with low dispersal ability. This is reinforced by the next chapter, in which I use reduced-representation genomic data in ten taxa of lowland Panamanian birds to test whether time is the most important predictor of the outcomes of secondary contact. I find no evidence that time plays a role in determining hybrid zone width in these taxa, and only a partial role in the generation of genomic variation. Instead, diet, which is again linked to dispersal ability as well as demographic changes, is a much better predictor. Finally, I move my focus in Chapter 3 to the Andes, using low-coverage whole genomes to examine the speciation history of the hummingbird genus Aglaeactis. This rapid radiation has significant mitonuclear discord, with completely different phylogenies reconstructed from mitochondrial and nuclear markers. In the two clades defined in the nuclear data, each made of three taxa, I then examined how divergence was distributed across the genome. The three southern taxa, all of which are in allopatry, have overall higher genomic divergence, but it is spread evenly across the genome. In the northern clade, though, I find much lower divergence punctuated by outliers of elevated differentiation. These northern taxa do have contact zones between them, and it is likely that gene flow in that geographic scenario has had a hand in shaping the genomic landscape for the development of reproductive isolation. Taken together, each of these chapters explores how reproductive isolation is the outcome of multiple facets of an organism interacting, and sheds further light on how avian biodiversity is generated

Depression Symptoms In Early Childhood Teachers: Do Personality, Social Support, And School Climate Play A Role?

Depression among early childhood teachers has received little attention within the United States. For the present study, early childhood teachers were asked to participate in an online survey to investigate the rate of high depression symptoms among teachers, and whether personality, social support, and school climate are related to teachers\u27 depression symptoms. Results showed that 32% of early childhood teachers in the sample were high in depression symptoms, which is significantly higher than rates of depression in the general population. Lower levels of neuroticism and higher levels of extroversion were related to fewer depression symptoms. Perceived social support from an administrator and other teachers\u27 openness were also related to fewer depression symptoms in early childhood teachers. The implications of these findings are important, such as effects teacher depression could have on teaching quality and students\u27 academic and psychosocial competence. Intervention options are also suggested, especially given the amount of pressure and scrutiny currently being placed on teachers in the United States

Parity at a Price: The Emerging Professional Liability of Mental Health Providers

This Article considers the issues associated with emerging professional liability claims against mental health care providers. Part II supplies background information regarding this liability, including the elements of these claims. Part III details the decreasing stigma associated with obtaining mental health services and its impact on professional liability, while Part IV summarizes advancements in mental health treatment that have enhanced the functional capacities of potential litigants. The remaining Parts explore changes in the delivery of mental health care where litigation may be focused, including the increasing use of psychotropic medications (Part V), the expanding role of primary care physicians and other health care providers with limited training and experience pertaining to the treatment of mental illness (Part VI), the surge in pediatric psychotropic prescriptions (Part VII), the emergence of the informed consent doctrine and psychiatric advance directives (Part VIII), and the continuing development of Tarasoff-related liability (Part IX)

An Intersectional Perspective on the Role of Workplace Policy Among Employed Female Caregivers During the Coronavirus Pandemic

Providing care for an older adult while working can be challenging, often leading to caregiver burden. The socioenvironmental context of the coronavirus pandemic creates additional complications for working caregivers. Women, who are the majority of informal caregivers, face unique stressors in the workplace (McKinsey & Company, 2019; Carnevale et al., 2018). Prior to and during the coronavirus pandemic, workplace policies have offered the potential of support, yet more information is needed on how working female informal caregivers of older adults of diverse identities receive, interpret, and experience these policies amidst the context of the pandemic. This study uses a phenomenological qualitative approach to explore caregiver burden from emotional, financial, physical, and work-related perspectives and caregivers’ experiences of relevant workplace policies. Interviews with 29 working female caregivers, ranging in age from 27 to 75 years old, were held between February and April 2021 via Zoom video conferencing technology. Analysis of written transcripts revealed the many facets of burden caregivers were facing during the pandemic, with an emphasis on the negative emotional impacts of this burden. Workplace policies that centered around flexibility and compensated workplace leave were identified as advantageous. Findings also pointed to the importance of a supportive supervisor and overall workplace culture as being critical factors that facilitated the use of accommodative workplace policies. From an intersectional perspective, a caregiver’s job status and rank in the workplace contributed to access to supportive workplace policies. This study highlights the necessity of creating more caring workplace cultures that conceptualize workers in the greater context of their lives outside of work. Future research would benefit by including a diverse sample of caregivers across various socioeconomic, educational, gender, and racial strata, including a quantitative component of caregiver burden, and querying more specific details of the caregiving scenario. Recommendations for workplace policies include the federal passage of a paid leave bill, tailoring workplace benefits to the needs of an organization’s workforce, allowing flexibility for all workers, and creating universal access to accommodative workplace policies to all employees at an organization, regardless of their job status

Remote Cameras Reveal Experimental Artifact in a Study of Seed Predation in a Semi-Arid Shrubland

Granivorous animals may prefer to predate or cache seed of certain plant species over others. Multiple studies have documented preference for larger, non-native seed by granivores. To accomplish this, researchers have traditionally used indirect inference by relating patterns of seed removal to the species composition of the granivorous animal community. To measure seed removal, researchers present seed to granivorous animals in the field using equipment intended to exclude certain animal taxa while permitting access to others. This approach allows researchers to differentiate patterns of seed removal among various taxa (e.g., birds, small mammals, and insects); however, it is unclear whether the animals of interest are freely using the exclusion devices, which may be a hindrance to discovering the seed dishes. We used video observation to perform a study of seed predation using a custom-built, infrared digital camera and recording system. We presented native and non-native seed mixtures in partitioned Petri dishes both within and outside of exclusion cages. The exclusion cages were intended to allow entrance by rodent taxa while preventing entrance by rabbits and birds. We documented all seed removal visits by granivorous animals, which we identified to the genus level. Genera exhibited varying seed removal patterns based on seed type (native vs. non-native) and dish type (open vs. enclosed). We documented avoidance of the enclosed dishes by all but one rodent taxa, even though these dishes were intended to be used freely by rodents. This suggests that preference for non-native seed occurs differentially among granivorous animals in this system; however, interpretation of these nuanced results would be difficult without the benefit of video observation. When feasible, video observation should accompany studies using in situ equipment to ensure incorrect assumptions do not lead to inappropriate interpretation of results

Sand & Swim Leg

Sand and Swim Leg, is addressing the clinical need of limited options for lower-limb amputees to participate in water activities. We will follow the FDA Medical Device Design Process throughout our two semester course. Initially, we created our team agreement and delegated team roles and responsibilities. Then, we conducted background research on the clinical need, competitive products, and existing patents. After compiling and discussing research amongst our team, we contacted stakeholders that would be affected by our product. Our stakeholders include our below-the-knee amputee client, an above-the-knee amputee, pediatric prosthetists, and our client’s prosthetists. We conducted interviews with our stakeholders to gain perspective on issues, successes, experiences with current prosthetics. Some issues that are present for current solutions include, uncomfortable, lack of ability to enter and exit the water, and expensive. We will follow up the User Needs stage of the process with the Design Input, Design Process, and Design Output. Our end goal for this process is a way for below-the-knee amputees to participate in water activities that is more affordable, functional, and comfortable than current options