Diversity In The Boreal Forest Of Alaska: Distribution And Impacts On Ecosystem Services

Thesis (Ph.D.) University of Alaska Fairbanks, 2012Within the forest management community, diversity is often considered as simply a list of species present at a location. In this study, diversity refers to species richness and evenness and takes into account vegetation structure (i.e. size, density, and complexity) that characterize a given forest ecosystem and can typically be measured using existing forest inventories. Within interior Alaska the largest forest inventories are the Cooperative Alaska Forest Inventory and the Wainwright Forest Inventory. The limited distribution of these inventories constrains the predictions that can be made. In this thesis, I examine forest diversity in three distinct frameworks; Recruitment, Patterns, and Production. In Chapter 1, I explore forest management decisions that may shape forest diversity and its role and impacts in the boreal forest. In Chapter 2, I evaluate and map the relationships between recruitment and species and tree size diversity using a geospatial approach. My results show a consistent positive relationship between recruitment and species diversity and a general negative relationship between recruitment and tree size diversity, indicating a tradeoff between species diversity and tree size diversity in their effects on recruitment. In Chapter 3, I modeled and mapped current and possible future forest diversity patterns within the boreal forest of Alaska using machine learning. The results indicate that the geographic patterns of the two diversity measures differ greatly for both current conditions and future scenarios and that these are more strongly influenced by human impacts than by ecological factors. In Chapter 4, I developed a method for mapping and predicting forest biomass for the boreal forest of interior Alaska using three different machine-learning techniques. I developed first time high resolution prediction maps at a 1 km2 pixel size for aboveground woody biomass. My results indicate that the geographic patterns of biomass are strongly influenced by the tree size class diversity of a given stand. Finally, in Chapter 5, I argue that the methods and results developed for this dissertation can aid in our understanding of forest ecology and forest management decisions within the boreal region

Prearchaic Adaptations in the Central Great Basin: Preliminary findings from a stratified open-air site in Grass Valley, Nevada

posterEarly Holocene occupants of the Great Basin preferentially occupied highly productive habitats surrounding pluvial lakes. While growing evidence details in the adaptations of these Prearchaic foragers in the Eastern (e.g., Madsen et al. 2015) and Western Great Basin (e.g., Jenkins et al. 2012), our understanding of the Central Great Basin remains impoverished, largely due to the limited number of stratified archaeological sites containing well preserved material suitable for faunal analysis and radiocarbon dating

In defense of quaking aspen (Populus tremuloides): the distribution and roles of phenolic glycosides and extrafloral nectaries within and among trees

Thesis (M.S.) University of Alaska Fairbanks, 2009"I studied the concentrations of phenolic glycosides (PGs) from leaves with and without extrafloral nectaries (EFNs) in Populus tremuloides during an outbreak of the aspen leaf miner, Phyllocnistis populiella, in interior Alaska. P. populiella feeds on the contents of epidermal cells from both top (adaxial) and bottom (abaxial) surfaces of P. tremuloides leaves. The objective of this study was to assess the association of chemical and biotic defenses in P. tremuloides and their interaction with the insect herbivore P. populiella. The concentration of PGs (salicortin and tremulacin) was approximately 70% greater in leaves bearing EFNs than in those without EFNs from short trees (<2.5 m); leaves with and without EFNs did not differ significantly in PG concentration for tall trees (5-8 m). Leaf mining caused the induction of the foliar PGs following eight days of mining. There was no difference in the ability of leaves with and without EFNs to induce PGs in response to mining. The extent of mining damage was significantly and negatively related to the PG concentration, whereas EFNs were not related to the extent of mining. At the site level, I found no evidence for a tradeoff between these two putative forms of defense in P. tremuloides"--Leaf iiiNational Science Foundation DEB 0543632General introduction -- Populus tremuloides -- Insect herbivores on P. tremuloides -- Secondary metabolites as a means of defense for P. tremuloides -- Extrafloral nectaries -- Defense traits within and among P. tremuloides -- Objectives of the study -- 1. The association between phenolic glycosides and extrafloral nectaries within and among individuals of Populus tremuloides -- 2. Epidermal leaf mining by Phyllocnistis populiella induces phenolic glycosides in quaking aspen -- General conclusions -- References

Release of cholesterol-rich particles from the macrophage plasma membrane during movement of filopodia and lamellipodia.

Cultured mouse peritoneal macrophages release large numbers of ~30-nm cholesterol-rich particles. Here, we show that those particles represent fragments of the plasma membrane that are pulled away and left behind during the projection and retraction of filopodia and lamellipodia. Consistent with this finding, the particles are enriched in proteins found in focal adhesions, which attach macrophages to the substrate. The release of particles is abolished by blocking cell movement (either by depolymerizing actin with latrunculin A or by inhibiting myosin II with blebbistatin). Confocal microscopy and NanoSIMS imaging studies revealed that the plasma membrane-derived particles are enriched in 'accessible cholesterol' (a mobile pool of cholesterol detectable with the modified cytolysin ALO-D4) but not in sphingolipid-sequestered cholesterol [a pool detectable with ostreolysin A (OlyA)]. The discovery that macrophages release cholesterol-rich particles during cellular locomotion is likely relevant to cholesterol efflux and could contribute to extracellular cholesterol deposition in atherosclerotic plaques

Control and Non-Payload Communications (CNPC) Prototype Radio Verification Test Report

This report provides an overview and results from the verification of the specifications that defines the operational capabilities of the airborne and ground, L Band and C Band, Command and Non-Payload Communications radio link system. An overview of system verification is provided along with an overview of the operation of the radio. Measurement results are presented for verification of the radios operation

DPP6 Localization in Brain Supports Function as a Kv4 Channel Associated Protein

The gene encoding the dipeptidyl peptidase-like protein DPP6 (also known as DPPX) has been associated with human neural disease. However, until recently no function had been found for this protein. It has been proposed that DPP6 is an auxiliary subunit of neuronal Kv4 K+ channels, the ion channels responsible for the somato-dendritic A-type K+ current, an ionic current with crucial roles in the regulation of firing frequency, dendritic integration and synaptic plasticity. This view has been supported mainly by studies showing that DPP6 is necessary to generate channels with biophysical properties resembling the native channels in some neurons. However, independent evidence that DPP6 is a component of neuronal Kv4 channels in the brain, and whether this protein has other functions in the CNS is still lacking. We generated antibodies to DPP6 proteins to compare their distribution in brain with that of the Kv4 pore-forming subunits. DPP6 proteins were prominently expressed in neuronal populations expressing Kv4.2 proteins and both types of protein were enriched in the dendrites of these cells, strongly supporting the hypothesis that DPP6 is an associated protein of Kv4 channels in brain neurons. The observed similarity in the cellular and subcellular patterns of expression of both proteins suggests that this is the main function of DPP6 in brain. However, we also found that DPP6 antibodies intensely labeled the hippocampal mossy fiber axons, which lack Kv4 proteins, suggesting that DPP6 proteins may have additional, Kv4-unrelated functions

DiagHunter and GenoPix2D: programs for genomic comparisons, large-scale homology discovery and visualization

The DiagHunter and GenoPix2D applications work together to enable genomic comparisons and exploration at both genome-wide and single-gene scales. DiagHunter identifies homologous regions (synteny blocks) within or between genomes. DiagHunter works efficiently with diverse, large datasets to predict extended and interrupted synteny blocks and to generate graphical and text output quickly. GenoPix2D allows interactive display of synteny blocks and other genomic features, as well as querying by annotation and by sequence similarity

CCD Photometry of the Classic Second Parameter Globular Clusters M3 and M13

We present high-precision V, B-V color-magnitude diagrams (CMDs) for the classic second parameter globular clusters M3 and M13 from wide-field deep CCD photometry. The data for the two clusters were obtained during the same photometric nights with the same instrument, allowing us to determine accurate relative ages. Based on a differential comparison of the CMDs using the Delta (B-V) method, an age difference of 1.7 +/- 0.7 Gyr is obtained between these two clusters. We compare this result with our updated horizontal-branch (HB) population models, which confirm that the observed age difference can produce the difference in HB morphology between the clusters. This provides further evidence that age is the dominant second parameter that influences HB morphology.Comment: 27 pages, 12 figures, Accepted for publication in A