Habitat selection and predation risk in larval lampreys

This thesis examines habitat preference and the influence of habitat on predation of larvae (ammocoetes) of the least brook lamprey (Lampetra aepyptera). The thesis comprises three chapters: (1) an introduction and literature review on the general life history of lampreys and on studies related to ammocoetes and their habitat, (2) an experimental study of habitat preference in ammocoetes of the least brook lamprey, and (3) an experimental study of the relationship between habitat availability and predation risk in ammocoetes. For the first study, we quantified substrate selection in small (\u3c 50 mm) and large (100-150 mm) ammocoetes of the least brook lamprey. In aquaria, ammocoetes were given a choice to burrow into six equally-available substrate types: small gravel (2.36-4.75 mm), coarse sand (0.5-1.4 mm), fine sand (0.125-0.5 mm), organic debris (approximately 70% decomposing leaves and stems, 15% silt, and 15% sand), an even mixture of silt, clay, and fine sand, and silt/clay (\u3c 0.063 mm). Fine sand was selected with a significantly higher probability than any other substrate. In the second study, we experimentally examined the influence of habitat availability on predation risk of ammocoetes. Ammocoetes were placed in aquaria containing a predator species (yellow bullhead, Ameiurus natalis) and one of 3 substrates: fine sand (0.125-0.5 mm), coarse sand (0.5-1.4 mm), or silt/clay (\u3c0.063 mm). Use of the three substrate types was based on a previous experiment where fine sand was determined to be the preferred benthic habitat of least brook lamprey. Based on 10 trials with each habitat type, survival of ammocoetes was highest in aquaria with fine sand (mean = 80%), and lower in those with coarse sand (mean = 58%) and silt/clay (mean = 4%). The results of both studies conducted indicate that populations of least brook lamprey ammocoetes may be limited by the availability of fine sand habitat. The first study indicated that least brook lamprey ammocoetes are habitat specialists, preferring substrates composed primarily of fine sand. The second study showed that the availability of fine sand habitat may influence the predation risk of ammocoetes, as ammocoete survival from predation was highest in fine sand, and lower in other substrates

Atypical Guillain-Barré in the Emergency Department

Guillain Barré Syndrome (GBS), although an uncommon diagnosis in the emergency department (ED), usually presents as one of the more common chief complaints—weakness. In this report we present an unusual case of weakness, initially seen in the ED and sent home only to return with worsening symptoms and ultimately found to be GBS

Codesigned Shared Decision-Making Diabetes Management Plan Tool for Adolescents With Type 1 Diabetes Mellitus and Their Parents: Prototype Development and Pilot Test

Background: Adolescents with type 1 diabetes mellitus have difficulty achieving optimal glycemic control, partly due to competing priorities that interfere with diabetes self-care. Often, significant diabetes-related family conflict occurs, and adolescents’ thoughts and feelings about diabetes management may be disregarded. Patient-centered diabetes outcomes may be better when adolescents feel engaged in the decision-making process. Objective: The objective of our study was to codesign a clinic intervention using shared decision making for addressing diabetes self-care with an adolescent patient and parent advisory board. Methods: The patient and parent advisory board consisted of 6 adolescents (teens) between the ages 12 and 18 years with type 1 diabetes mellitus and their parents recruited through our institution’s Pediatric Diabetes Program. Teens and parents provided informed consent and participated in 1 or both of 2 patient and parent advisory board sessions, lasting 3 to 4 hours each. Session 1 topics were (1) patient-centered outcomes related to quality of life, parent-teen shared diabetes management, and shared family experiences; and (2) implementation and acceptability of a patient-centered diabetes care plan intervention where shared decision making was used. We analyzed audio recordings, notes, and other materials to identify and extract ideas relevant to the development of a patient-centered diabetes management plan. These data were visually coded into similar themes. We used the information to develop a prototype for a diabetes management plan tool that we pilot tested during session 2. Results: Session 1 identified 6 principal patient-centered quality-of-life measurement domains: stress, fear and worry, mealtime struggles, assumptions and judgments, feeling abnormal, and conflict. We determined 2 objectives to be principally important for a diabetes management plan intervention: (1) focusing the intervention on diabetes distress and conflict resolution strategies, and (2) working toward a verbalized common goal. In session 2, we created the diabetes management plan tool according to these findings and will use it in a clinical trial with the aim of assisting with patient-centered goal setting. Conclusions: Patients with type 1 diabetes mellitus can be effectively engaged and involved in patient-centered research design. Teens with type 1 diabetes mellitus prioritize reducing family conflict and fitting into their social milieu over health outcomes at this time in their lives. It is important to acknowledge this when designing interventions to improve health outcomes in teens with type 1 diabetes mellitus

Influence of Environmental Stress and Anthropogenic Disturbance on the Energy Expenditure of Wintering Northern Pintails (Anas acuta)

Winter conditions impose hardships on waterfowl, impacting how they apportion energy and time. Human disturbances may affect this energetic balance, influence lipid reserves, and potentially survival. Objectives of this study were to determine effects of environmental and anthropogenic factors on energetic expenditure (kcal/day) of Northern Pintails (Anas acuta) in behaviors commonly associated with a disturbance response (alert, locomotion, and flight) during winter 2008-2009 and 2009-2010 at Bosque del Apache National Wildlife Refuge in central New Mexico, USA. The refuge is a frequently visited ecotourism destination with over 170,000 visitors each winter. Thermoregulatory cost, time-of-winter, amount of natural and anthropogenic disturbances, and forage availability were examined to determine their influence on pintail energetic response (e.g., flight, locomotion, alert behavior). Average number of pintails ranged from 7,524-15,769. Using Akaike Information Criteria, the top-ranked model indicated that increased thermoregulatory cost, and by association decreased temperature, may cause a decline in energetic response of pintails to disturbances. Modeled values for energetic response had a mean (± SE) of 175 ± 11.5 kcal/day in year 1, and 111.7 ± 7.22 kcal/day in year 2. Neither the amount of disturbance nor forage availability strongly influenced energetic response. Results of this study raise questions about the efficacy of using behavior or energy expenditure data, alone, to assess anthropogenic disturbance effects on waterfowl

Population-average mediation analysis for zero-inflated count outcomes

Mediation analysis is an increasingly popular statistical method for explaining causal pathways to inform intervention. While methods have increased, there is still a dearth of robust mediation methods for count outcomes with excess zeroes. Current mediation methods addressing this issue are computationally intensive, biased, or challenging to interpret. To overcome these limitations, we propose a new mediation methodology for zero-inflated count outcomes using the marginalized zero-inflated Poisson (MZIP) model and the counterfactual approach to mediation. This novel work gives population-average mediation effects whose variance can be estimated rapidly via delta method. This methodology is extended to cases with exposure-mediator interactions. We apply this novel methodology to explore if diabetes diagnosis can explain BMI differences in healthcare utilization and test model performance via simulations comparing the proposed MZIP method to existing zero-inflated and Poisson methods. We find that our proposed method minimizes bias and computation time compared to alternative approaches while allowing for straight-forward interpretations.Comment: 34 pages, 2 figures, 4 tables, 49 pages of Supplemental material, 2 supplemental figure

Diverse histone modifications on histone 3 lysine 9 and their relation to DNA methylation in specifying gene silencing

<p>Abstract</p> <p>Background</p> <p>Previous studies of individual genes have shown that in a self-enforcing way, dimethylation at histone 3 lysine 9 (dimethyl-H3K9) and DNA methylation cooperate to maintain a repressive mode of inactive genes. Less clear is whether this cooperation is generalized in mammalian genomes, such as mouse genome. Here we use epigenomic tools to simultaneously interrogate chromatin modifications and DNA methylation in a mouse leukemia cell line, L1210.</p> <p>Results</p> <p>Histone modifications on H3K9 and DNA methylation in L1210 were profiled by both global CpG island array and custom mouse promoter array analysis. We used chromatin immunoprecipitation microarray (ChIP-chip) to examine acetyl-H3K9 and dimethyl-H3K9. We found that the relative level of acetyl-H3K9 at different chromatin positions has a wider range of distribution than that of dimethyl-H3K9. We then used differential methylation hybridization (DMH) and the restriction landmark genome scanning (RLGS) to analyze the DNA methylation status of the same targets investigated by ChIP-chip. The results of epigenomic profiling, which have been independently confirmed for individual loci, show an inverse relationship between DNA methylation and histone acetylation in regulating gene silencing. In contrast to the previous notion, dimethyl-H3K9 seems to be less distinct in specifying silencing for the genes tested.</p> <p>Conclusion</p> <p>This study demonstrates in L1210 leukemia cells a diverse relationship between histone modifications and DNA methylation in the maintenance of gene silencing. Acetyl-H3K9 shows an inverse relationship between DNA methylation and histone acetylation in regulating gene silencing as expected. However, dimethyl-H3K9 seems to be less distinct in relation to promoter methylation. Meanwhile, a combination of epigenomic tools is of help in understanding the heterogeneity of epigenetic regulation, which may further our vision accumulated from single-gene studies.</p

Directly Comparing Handoff Protocols for Pediatric Hospitalists

BACKGROUND AND OBJECTIVES: Handoff protocols are often developed by brainstorming and consensus, and few are directly compared. We hypothesized that a handoff protocol (Flex 11) developed using a rigorous methodology would be more favorable in terms of clinicians’ attitudes, behaviors, cognitions, or time-on-task when performing handoffs compared with a prevalent protocol (Situation Background Assessment Recommendation [SBAR]). METHODS: Using a between-groups, randomized control trial design (Flex 11 versus SBAR) during a pilot study in a simulated environment, 20 clinicians (13 attending physicians and 7 residents) received 3 patient handoffs from a standardized physician, managed the patients, and handed off the patients to the same standardized physician. Participants completed surveys assessing their attitudes and cognitions, and behaviors and handoff duration were assessed through observations. RESULTS: All data were analyzed using independent samples t tests. For attitudes, “ease of use” ratings were lower for SBAR participants than Flex 11 participants (P , .01), and “being helpful” ratings were lower for SBAR participants than Flex 11 participants (P 5 .02). For behaviors, results indicate no significant difference in the information acquired between the SBAR and Flex 11 protocols. However, SBAR participants gave significantly less information than Flex 11 participants (P , .01). For cognitions, SBAR and Flex 11 participants reported similar workload except for frustration. For handoff duration, there were no significant differences between the protocols (P 5 .36). CONCLUSIONS: The results suggest that Flex 11 is an efficient, beneficial tool in a simulated environment with pediatric clinicians. Future studies should evaluate this protocol in the inpatient setting

Whole genomic sequence analysis of \u3ci\u3eBacillus infantis\u3c/i\u3e: defining the genetic blueprint of strain NRRL B-14911, an emerging cardiopathogenic microbe

Background: We recently reported the identification of Bacillus sp. NRRL B-14911 that induces heart autoimmunity by generating cardiac-reactive T cells through molecular mimicry. This marine bacterium was originally isolated from the Gulf of Mexico, but no associations with human diseases were reported. Therefore, to characterize its biological and medical significance, we sought to determine and analyze the complete genome sequence of Bacillus sp. NRRL B-14911. Results: Based on the phylogenetic analysis of 16S ribosomal RNA (rRNA) genes, sequence analysis of the 16S-23S rDNA intergenic transcribed spacers, phenotypic microarray, and matrix-assisted laser desorption ionization time-offlight mass spectrometry, we propose that this organism belongs to the species Bacillus infantis, previously shown to be associated with sepsis in a newborn child. Analysis of the complete genome of Bacillus sp. NRRL B-14911 revealed several virulence factors including adhesins, invasins, colonization factors, siderophores and transporters. Likewise, the bacterial genome encodes a wide range of methyl transferases, transporters, enzymatic and biochemical pathways, and insertion sequence elements that are distinct from other closely related bacilli. Conclusions: The complete genome sequence of Bacillus sp. NRRL B-14911 provided in this study may facilitate genetic manipulations to assess gene functions associated with bacterial survival and virulence. Additionally, this bacterium may serve as a useful tool to establish a disease model that permits systematic analysis of autoimmune events in various susceptible rodent strains