Plant and insect-mediated invasiveness of Phragmites australis and the litter dynamics and biodiversity of six freshwater macrophytes

My thesis involves two distinct projects related to wetland plants. The first evaluates plant traits for their contribution to the success of invasive Phragmites australis in North America and their interaction with herbivores. The second investigates the relative effects of six plant species, with different growth forms, status (native v. nonnative) and tissue quality, on litter dynamics and invertebrate diversity in a New York freshwater wetland. Prevention is the most cost-effective and successful means of managing invasive plants. Predicting future invasions depends on identifying plant traits that facilitate invasive success. We investigated the influence of above-ground growth phenology and increased stem height on the success of invasive Phragmites australis in North America, using a phylogenetically-controlled comparison with a native, non-weedy P. australis subspecies. We also measured the effects of specialist stem-galling Lipara flies and a generalist aphid (Hyalopterus pruni), both nonnatives to North America, on these above-ground traits. Comparisons were made in 1) a common garden at Cornell University, Ithaca, NY, in 2003 and 2004, and 2) a field site at Montezuma National Wildlife Refuge, Seneca Falls, NY in 2003. In the garden, but not the field, nonnative P. australis leaves remained green for about a month longer (native v. nonnative: 2003 = 59.93 v. 85.5 days, P = 0.0002; 2004 = 52.29 v. 87.39 days, P = 0.02). For nonnative P. australis, leaves of the upper canopy consistently lived longer while leaf lifespan in the lower canopy was shorter or the same. Greater investment in high canopy leaves may increase carbon gain efficiency of nonnative P. australis. Nonnative P. australis grew taller in the field but this was mediated by disproportionate Lipara attack rather than plant status (native or nonnative). Lipara attack reduced stem height of all stems but only increased the lifespan of nonnative P. australis? low canopy leaves. Aphids had no significant effect on measured plant traits. Through increased carbon gain, leaf phenology may contribute to P. australis? competitive superiority over its native conspecific. Higher susceptibility of native P. australis to nonnative herbivores may also facilitate nonnative P. australis? competitive superiority. Senesced plant litter from emergent macrophytes fuels freshwater wetland productivity and nutrient cycling. Litter nitrogen content generally has a direct, positive effect on quantity and rate of resource availability to wetland biota. Since plants vary in their nitrogen content, shifts in plant community composition may alter important wetland functions. To study the consequences of changing plant dominance, we compared litter mass loss and invertebrate richness and abundance of six common macrophytes in a central New York freshwater wetland. Plants studied include Typha latifolia L. (broad leafed cattail, Typhacea), T. angustifolia L. (narrow leafed cattail), Phragmites australis (cav.) Trin ex. Steudel (common reed, Poaceae), P. australis subspecies americanus Saltonstall, P.M. Peterson & Soreng, Lythrum salicaria L. (purple loosestrife, Lythraceae), and Phalaris arundinacea L. (reed canarygrass, Poaceae). After nine months, mass loss of most plant species diverged significantly. Plant effect on invertebrate colonization was season and species-specific, with P. arundinacea almost consistently supporting higher invertebrate densities. Although %N differed among some plant species, it was not a good predictor of mass loss or invertebrate abundance and richness. Including plastic drinking straws as a treatment revealed that several invertebrates used litter for substrate rather than food. We conclude that shifts in plant dominance among the six wetland macrophytes investigated could potentially alter wetland function, by changing decomposition rates and the invertebrate community. Net quality of litter resources, which depends on the combined influence of morphology, chemical quality of specific plant organs, and feeding ecology of specific taxa, may be a better predictor of species effects on decomposition and diversity

Design of components for the NASA OCEAN project

The goal of the Fall 1993 semester of the EGM 4000 class was to design, fabricate, and test components for the 'Ocean CELSS Experimental Analog NASA' Project (OCEAN Project) and to aid in the future development of NASA's Controlled Ecological Life Support System (CELSS). The OCEAN project's specific aims are to place a human, Mr. Dennis Chamberland from NASA's Life Science Division of Research, into an underwater habitat off the shore of Key Largo, FL for three months. During his stay, he will monitor the hydroponic growth of food crops and evaluate the conditions necessary to have a successful harvest of edible food. The specific designs chosen to contribute to the OCEAN project by the EGM 4000 class are in the areas of hydroponic habitat monitoring, human health monitoring, and production of blue/green algae. The hydroponic monitoring system focused on monitoring the environment of the plants. This included the continuous sensing of the atmospheric and hydroponic nutrient solution temperatures. Methods for monitoring the continuous flow of the hydroponic nutrient solution across the plants and the continuous supply of power for these sensing devices were also incorporated into the design system. The human health monitoring system concentrated on continuously monitoring various concerns of the occupant in the underwater living habitat of the OCEAN project. These concerns included monitoring the enclosed environment for dangerous levels of carbon monoxide and smoke, high temperatures from fire, and the ceasing of the continuous airflow into the habitat. The blue/green algae project emphasized both the production and harvest of a future source of food. This project did not interact with any part of the OCEAN project. Rather, it was used to show the possibility of growing this kind of algae as a supplemental food source inside a controlled ecological life support system

Holographic QCD: Past, Present, and Future

At the dawn of a new theoretical tool based on the AdS/CFT correspondence for nonperturbative aspects of quantum chromodynamics, we give an interim review on the new tool, holographic QCD, with some of its accomplishment. We try to give an A-to-Z picture of the holographic QCD, from string theory to a few selected top-down holographic QCD models with one or two physical applications in each model. We may not attempt to collect diverse results from various holographic QCD model studies.Comment: 80 pages, 18 figures, LaTeX; references added, published version + appendi

Occupational Lymphohematopoietic Cancer in Korea

The purpose of this study was to review the existing studies on lymphohematopoietic (LHP) cancer in Korea, estimate the prevalence of workers exposed to carcinogens, and determine the population attributable fraction (PAF) of leukemia. Two case series and 4 case reports were reviewed. Using official statistics, the prevalence of benzene exposure and ionizing radiation exposure was estimated. Based on the prevalence of exposure and the relative risk, The PAF of leukemia was calculated. Between 1996 and 2005, 51 cases of LHP cancer were reported from the compensation system. Greater than 50% of occupational LHP cancer was leukemia, and the most important cause was benzene. In a cohort study, the standardized incidence ratio was 2.71 (95% CI, 0.56-7.91). The prevalence of exposure was 2.5% and 2.2% in 1995 and 2000, respectively. Using the 1995 prevalence, 3.6-4.8% and 0.1% of cases with leukemia were attributable to benzene and ionizing radiation exposure, respectively, which resulted in 39.7-51.4 cases per year. Benzene is the most important cause of occupational leukemia in Korea. Considering the estimated PAF in this study, the annual number of occupational LHP cancer (51 cases during 10-yr period), might be underreported within the compensation system

"'Asianness Under Construction:' The Contours and Negotiation of Panethnic Identity/Culture among Interethnically Married Asian Americans."

Based on life-history interviews of interethnically married U.S.-raised Asians, this article examines the meaning and dynamics of Asian American interethnic marriages, and what they reveal about the complex incorporative process of this “in-between” racial minority group into the U.S.. In particular, this article explores the connection between Asian American interethnic marriage and pan-Asian consciousness/identity, both in terms of how panethnicity shapes romantic/ marital desires of individuals and how pan-Asian culture and identity is invented and negotiated in the process of family-making. My findings indicate that while strong pan-Asian consciousness/ identity underlies the connection among intermarried couples, these unions are not simply a defensive effort to “preserve” Asian-ethnic identity and cultur against a society that still racializes Asian Americans, but a tentative and often unpremeditated effort to navigate a path toward integration into the society through an ethnically based, albeit hybrid and reconstructed identity and culture, that helps the respondents retain the integrity of “Asianness.

Porcine sapovirus Cowden strain enters LLC-PK cells via clathrin- and cholesterol-dependent endocytosis with the requirement of dynamin II.

Caliciviruses in the genus Sapovirus are a significant cause of viral gastroenteritis in humans and animals. However, the mechanism of their entry into cells is not well characterized. Here, we determined the entry mechanism of porcine sapovirus (PSaV) strain Cowden into permissive LLC-PK cells. The inhibition of clathrin-mediated endocytosis using chlorpromazine, siRNAs, and a dominant negative (DN) mutant blocked entry and infection of PSaV Cowden strain, confirming a role for clathrin-mediated internalization. Entry and infection were also inhibited by the cholesterol-sequestering drug methyl-β-cyclodextrin and was restored by the addition of soluble cholesterol, indicating that cholesterol also contributes to entry and infection of this strain. Furthermore, the inhibition of dynamin GTPase activity by dynasore, siRNA depletion of dynamin II, or overexpression of a DN mutant of dynamin II reduced the entry and infection, suggesting that dynamin mediates the fission and detachment of clathrin- and cholesterol-pits for entry of this strain. In contrast, the inhibition of caveolae-mediated endocytosis using nystatin, siRNAs, or a DN mutant had no inhibitory effect on entry and infection of this strain. It was further determined that cell entry of PSaV Cowden strain required actin rearrangements for vesicle internalization, endosomal trafficking from early to late endosomes through microtubules, and late endosomal acidification for uncoating. We conclude that PSaV strain Cowden is internalized into LLC-PK cells by clathrin- and cholesterol-mediated endocytosis that requires dynamin II and actin rearrangement, and that the uncoating occurs in the acidified late endosomes after trafficking from the early endosomes through microtubules

Quantifiable Assessment of SWNT Dispersion in Polymer Composites

NASA LaRC has established a new protocol for visualizing the nanomaterials in structural polymer matrix resins. Using this new technique and reconstructing the 3D distribution of the nanomaterials allows us to compare this distribution against a theoretically perfect distribution. Additional tertiary structural information can now be obtained and quantified with the electron tomography studies. These tools will be necessary to establish the structural-functional relationships between the nano and the bulk. This will also help define the critical length scales needed for functional properties. Field ready tool development and calibration can begin by using these same samples and comparing the response. i.e. gold standards of good and bad dispersion

In vivo biosensing via tissue-localizable near-infrared-fluorescent single-walled carbon nanotubes

Single-walled carbon nanotubes are particularly attractive for biomedical applications, because they exhibit a fluorescent signal in a spectral region where there is minimal interference from biological media. Although single-walled carbon nanotubes have been used as highly sensitive detectors for various compounds, their use as in vivo biomarkers requires the simultaneous optimization of various parameters, including biocompatibility, molecular recognition, high fluorescence quantum efficiency and signal transduction. Here we show that a polyethylene glycol ligated copolymer stabilizes near-infrared-fluorescent single-walled carbon nanotubes sensors in solution, enabling intravenous injection into mice and the selective detection of local nitric oxide concentration with a detection limit of 1 µM. The half-life for liver retention is 4 h, with sensors clearing the lungs within 2 h after injection, thus avoiding a dominant route of in vivo nanotoxicology. After localization within the liver, it is possible to follow the transient inflammation using nitric oxide as a marker and signalling molecule. To this end, we also report a spatial-spectral imaging algorithm to deconvolute fluorescence intensity and spatial information from measurements. Finally, we demonstrate that alginate-encapsulated single-walled carbon nanotubes can function as implantable inflammation sensors for nitric oxide detection, with no intrinsic immune reactivity or other adverse response for more than 400 days.National Institutes of Health (U.S.) (T32 Training Grant in Environmental Toxicology ES007020)National Cancer Institute (U.S.) (Grant P01 CA26731)National Institute of Environmental Health Sciences (Grant P30 ES002109)Arnold and Mabel Beckman Foundation (Young Investigator Award)National Science Foundation (U.S.). Presidential Early Career Award for Scientists and EngineersScientific and Technological Research Council of Turkey (TUBITAK 2211 Research Fellowship Programme)Scientific and Technological Research Council of Turkey (TUBITAK 2214 Research Fellowship Programme)Middle East Technical University. Faculty Development ProgrammeSanofi Aventis (Firm) (Biomedical Innovation Grant