3,081 research outputs found
Using Migration Monitoring Data to Assess Bird Population Status and Behavior in a Changing Environment
Across the world, researchers use migration banding stations to document bird migration and study the phenomenon. In this dissertation, I focus on ways of analyzing bird migration banding data and the utility migrating birds as indicators of ecosystem health that make these monitoring efforts more useful to answering ecological questions and managing migratory species. In Chapter 1, we provide background on hierarchical modeling and an overview of our findings. In Chapter 2, we developed and validated new methods to estimate daily changes in migratory population size while controlling for changes in detectability due to environmental conditions. In Chapter 3, this modeling technique was then employed to evaluate the continental-scale and the local-scale determinants of migratory population size for ten species of migrants using a Key Biscayne, FL site for migratory stopover in the fall. Species showed diverse relationships between abundance and local weather conditions. Wet conditions on the breeding grounds consistently increased migratory onset and dry conditions on the non-breeding grounds from the previous winter consistently reduced population size across all species. In Chapter 4, we looked at how daily changes in migrant density influenced the stopover behavior of seven songbirds at the Key Biscayne stopover site. Density-dependence had positive and negative effects on mass gain across species, the chance of that effect being negative increased with the average daily stopover population size of the species. Density-dependence was hypothesized to be a function of overall migrant abundance at the site, with only highly abundance species showing negative effects. Finally, in Chapter 5 migrating birds are used to tell us about contaminant exposure in their breeding and non-breeding environments. We found higher amount of mercury in fall than the spring and there was evidence that fall mercury exposure was altering migratory behavior. These patterns provide the first evidence that Hg exposure alters migratory physiology in songbirds. Overall, this dissertation suggests that migration monitoring is useful for both basic and applied research and provide a tool for understanding the complicated life cycles of migratory animals
Burstiness and Stochasticity in the Malleability of Physical Activity
This study examined whether patterns of self-organization in physical activity (PA) predicted long-term success in a yearlong PA intervention. Increased moderate to vigorous PA (MVPA) was targeted in insufficiently active adults (Nā=ā512) via goal setting and financial reinforcement. The degree to which inverse power law distributions, which are reflective of self-organization, summarized (a) daily MVPA and (b) time elapsed between meeting daily goals (goal attainment interresponse times) was calculated. Goal attainment interresponse times were also used to calculate burstiness, the degree to which meeting daily goals clustered in time. Inverse power laws accurately summarized interresponse times, but not daily MVPA. For participants with higher levels of MVPA early in the study, burstiness in reaching goals was associated with long-term resistance to intervention, while stochasticity in meeting goals predicted receptiveness to intervention. These results suggest that burstiness may measure self-organizing resistance to change, while PA stochasticity could be a precondition for behavioral malleability
The effect of an Enhanced Isopentenyl Monophosphate Pool on Terpenoid Biosynthesis in vivo
Found in all living organisms, terpenoids make up the largest group of natural products and are essential compounds for many major processes, including photosynthesis, respiration, hormone production, and electron transport. Additionally, they have commercial and medical value in products including fragrances, cosmetics, and medicines. Terpenoids originate from the five-carbon building blocks isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP), which are synthesized by the mevalonic acid (MVA) and methylerithritol phosphate (MEP) pathways. An alternative MVA pathway was discovered in Archaea with the final two enzymes being phosphomevalonate decarboxylase (MPD) and isopentenyl phosphate kinase (IPK). Even though this alternative pathway is not present in plants, presence of IPK was retained. The overexpression of IPK in planta indicates that IPK plays a significant role in the MVA pathway by synthesizing IPP/DMAPP from an IP/DMAP pool for terpenoid biosynthesis. It has been suggested that this monophosphate pool regulates downstream carbon flux by inhibiting farnesyl diphosphate synthase (FPPS). By utilizing MPD from the archeabacterium Roseiflexus castenholzii, we can see how an increased isopentenyl (IP) pool affects downstream terpenoid biosynthesis. To do this, RcMPD was overexpressed in the background of Arabidopsis thaliana T-DNA insertion lines of a knockdown of IPK. These lines were tested for expression of MPD/IPK using qrt-PCR and terpenoids were analyzed via sterol extraction and scent collection. Levels of monoterpenes (MEP pathway products) and sesquiterpenes (MVA pathway products) were significantly reduced, suggesting that a larger monophosphate pool reduces downstream synthesis of farnesyl diphosphate, a precursor for sterol and sesquiterpene biosynthesis
Constraints on vacuum energy from structure formation and Nucleosynthesis
This paper derives an upper limit on the density ĻĪ of dark energy based on the requirement that cosmological structure forms before being frozen out by the eventual acceleration of the universe. By allowing for variations in both the cosmological parameters and the strength of gravity, the resulting constraint is a generalization of previous limits. The specific parameters under consideration include the amplitude Q of the primordial density fluctuations, the Planck mass Mpl, the baryon-to-photon ratio Ī·, and the density ratio Ī©M/Ī©b. In addition to structure formation, we use considerations from stellar structure and Big Bang Nucleosynthesis (BBN) to constrain these quantities. The resulting upper limit on the dimensionless density of dark energy becomes ĻĪ/Mpl4 < 10ā90, which is ~30 orders of magnitude larger than the value in our universe ĻĪ/Mpl4 ~ 10ā120. This new limit is much less restrictive than previous constraints because additional parameters are allowed to vary. With these generalizations, a much wider range of universes can develop cosmic structure and support observers. To constrain the constituent parameters, new BBN calculations are carried out in the regime where Ī· and G = Mplā2 are much larger than in our universe. If the BBN epoch were to process all of the protons into heavier elements, no hydrogen would be left behind to make water, and the universe would not be viable. However, our results show that some hydrogen is always left over, even under conditions of extremely large Ī· and G, so that a wide range of alternate universes are potentially habitable
Pan-cancer analysis reveals cooperativity of both strands of microRNA that regulate tumorigenesis and patient survival
Recently, both 5p and 3p miRNA strands are being recognized as functional instead of only one, leaving many miRNA strands uninvestigated. To determine whether both miRNA strands, which have different mRNA-targeting sequences, cooperate to regulate pathways/functions across cancer types, we evaluate genomic, epigenetic, and molecular profiles of \u3e5200 patient samples from 14 different cancers, and RNA interference and CRISPR screens in 290 cancer cell lines. We identify concordantly dysregulated miRNA 5p/3p pairs that coordinately modulate oncogenic pathways and/or cell survival/growth across cancers. Down-regulation of both strands of miR-30a and miR-145 recurrently increased cell cycle pathway genes and significantly reduced patient survival in multiple cancers. Forced expression of all four strands show cooperativity, reducing cell cycle pathways and inhibiting lung cancer cell proliferation and migration. Therefore, we identify miRNA whose 5p/3p strands function together to regulate core tumorigenic processes/pathways and reveal a previously unknown pan-cancer miRNA signature with patient prognostic power
Job-Related Burnout among Juvenile Probation Officers: Implications for Mental Health Stigma and Competency
The high demands and responsibilities of probation work, particularly with juvenile clients, may lead to burnout, which can negatively impact how probation officers work with clients, particularly individuals with behavioral health concerns. Yet, research examining burnout and related outcomes among juvenile probation officers (JPOs) is limited. We surveyed 246 JPOs in a Midwestern state to identify the prevalence, predictors, and potential outcomes of burnout. JPOs reported moderate levels of burnout; about 30% of the sample scored in the high range for emotional exhaustion and cynicism. Contrary to study hypotheses, there were no group-level differences in burnout scores across gender, race/ethnicity, age, or education. In regression models, burnout was predicted by being White (vs. minority), serving in an urban (vs. rural) county, dissatisfaction with department guidelines, job dissatisfaction, viewing job role as more treatment-oriented along the enforcementātreatment continuum, and turnover intention. JPOs with burnout were more likely to endorse mental health stigma and lack of mental health competency to address juvenile clients with behavioral health concerns. Findings suggest burnout prevention and intervention programs should be considered for JPOs to increase job satisfaction, limit job turnover, reduce burnout, and possibly increase effective practices for managing juvenile clients with behavioral health needs
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