Spring 2010

Solar Chimneys and Inflatable Vacuum Chambers: a new approach in renewable energy

Sean Barton
Florida State University

Hosting Dept: Physics, Astronomy and Geosciences

Abstract:  Solar chimneys, comprised of a "greenhouse", turbine, and chimney, are facilities for producing electricity from sunlight. A prototype facility operated in Spain from 1982 to 1989. For an efficient system, the chimney must be of extreme height. Thus the chimney constitutes the major construction cost of the design. A 1000-meter chimney of reinforced concrete, planned for Mildura, Australia, was estimated to cost $800 million. Despite attempts to reduce the cost, the project was finally canceled in 2009. The economics of solar chimneys remain difficult. We now suggest that the solution to these difficulties may lie in an apparently unrelated investigation, inflatable vacuum chambers. The idea dates back to 1921, possibly earlier. Some prototype "3-layer" structures were built in 1994 and instabilities were observed. In 2008, the speaker analyzed these instabilities theoretically and predicted that some "5-layer" structures would avoid these difficulties. Stable 5-layer structures have now been demonstrated. Such structures may have applications in airship design, aerospace, industry, transportation, and solar energy production. In this last potential application we find the connection with solar chimneys. Inflatable chimneys have been considered as an alternative to "brick-and-mortar" chimneys for the purpose of reducing weight, cost, and height limitations. The idealized inflatable tower is discussed. The need for compartmentalization, buoyancy, and moorings is established.

Abstract:  This talk will provide brief overviews on several research projects that are taking place this academic year. The first is the design of a nano-satellite by four students that is powered and controlled by nanotech components. Its mission is to deliver genetic material to the moon Europa. Second, three students are involved in three weather balloon launches to the top of the stratosphere. The launches are planned from different locations in south Georgia and north Florida. The payload on each launch includes electronic monitoring equipment and high tech material made at VSU that will be studied to examine the effects of extremes in radiation, pressure and temperature of the upper atmosphere (100,000 ft) on the carbon based material. Third, a student is working on a novel experiment using concentrated microwaves to make C60 or fullerenes that has been developed and is being further tested will be discussed. Two students are using multiangle laser light scattering (MALLS) to study the aqueous phase structure of DNA fragments and the aggregation of certain drugs. Also, our periodic puzzle project, a collaborative project with students in Cuba, (www.valdosta.edu/periodicpuzzles) will be outlined. Finally, the current status of our bacteria farms in the Gulf of Mexico that are producing pharmaceutical agents will be outlined.

Distributed Bipartite Matching and Its Applications to Network Switch Scheduling

Dr. Krishnendu Roy
Valdosta State University

Hosting Dept: Math and Computer Science

Abstract:  Graph theory is an important branch of Computer Science that deals with modeling various real life discrete problems. Graph matching is an important problem of graph theory. Selecting a subset of edges of a graph such that no two edges have the same end-points is known as graph matching. When a matching is computed on a special kind of graph, bipartite graph, the problem is called bipartite graph matching or simply bipartite matching. Bipartite matching is relatively easy to understand, yet one can use it to solve various complicated problems spanning different scientific disciplines including computer science, operations research, and bioinformatics. Part of my research involves using a mesh like structure of processing elements to generate bipartite matching in a distributed fashion. Generating matching is a computationally intensive task; hence distributed approaches are often preferred. In this talk I will give an overview of general graph matching, bipartite matching, and some applications of bipartite matching. Subsequently, I will present a distributed bipartite matching algorithm that we developed as a part of my doctoral research. Our algorithm runs on a distributed 2-D mesh of processing elements and is very efficient. The mesh layout of processing elements is very similar in structure to a network switch and hence is well suited for that application.

The Upward Spiral

Dr. Laura Regassa
Georgia Southern University

Hosting Dept: Biology

Abstract:  Traditional strain classification divides the genus Spiroplasma into 38 groups based on surface serology, with broad host ranges including plants, insects and crustaceans. Given the ubiquitous nature of these microbes, a methodical approach that focuses on serologically distinct isolates from a single host family is being used as an initial step in understanding spiroplasma diversity and distribution. Tabanid flies are an attractive host for a biodiversity study because they appear to be generalists with respect to spiroplasma carriage, and tabanid-associated spiroplasmas represent the most thoroughly studied group to date. This project is examining a spiroplasma field isolate collection (>200 isolates) that was obtained from tabanid flies in Costa Rica, Ecuador, Australia, and the United States. Initial serological analyses revealed the presence of 29 groups of long-form spiroplasma isolates among the novel field isolates, including 23 new serogroups (= putative new species). We are currently examining representatives of the different serogroups using phylogenetic analyses and non-genetic character mapping. The talk will detail the results of our study to date and provide information concerning the Molecular Biology Initiative Program, a unique NSF-funded opportunity for new graduate students.

Role of mitochondrial dysfunction in cardiovascular diseases

Dr. Sergey Dikalov
Director of Free Radicals in Medicine Core
Emory University School of Medicine Atlanta, GA

Hosting Dept: Chemistry

Abstract:  Mitochondria are not just an ATP cow. They are recognized regulators of cell death in and remodeling process. Mitochondrial dysfunction is associated with cardiovascular diseases (CVD) however the exact role of mitochondria is not clear. Inherited and sporadic mitochondrial diseases caused by mutations to mitochondrial genes in mitochondrial or nuclear DNA are well documented. Meanwhile, mitochondrial dysfunction can be a source and course of oxidative stress. Mitochondria and NADPH oxidases are important sources of vascular reactive oxygen species (ROS) such as O2• and H2O2. Overproduction of ROS may results in decreased bioavailability of nitric oxide (NO•) and endothelial dysfunction. We have found that stimulation of endothelial cells with angiotensin II (AngII) increases production of mitochondrial ROS and impairs mitochondrial respiration. Depletion of p22phox subunit of NADPH oxidase with siRNA inhibits AngII-induced mitochondrial dysfunction. Inhibition of mitochondrial mitoKATP or reverse electron flow diminishes mitochondrial ROS, decreases activity of NADPH oxidase and increased endothelial NO•. We suggest that AngII induced O2• production by NADPH oxidase stimulates production of mitochondrial O2• that in turn provides redox dependent feed forward stimulation of NADPH oxidase. This vicious cycle can be interrupted at the mitochondrial site by mitochondria targeted antioxidants. We have developed a mitochondria-targeted SOD mimetic, mitoTEMPO, by conjugating the lipophilic triphenylphosphonium cation to an antioxidant moiety TEMPO. As expected, inhibition of mitochondrial oxidative stress with SOD2 overexpression or supplementation with mitoTEMPO attenuates endothelial oxidative stress, restores NO• production, improves endothelium-dependent vasodilatation and reduces blood pressure in AngII infused mice. The upstream activators and downstream targets of mitochondrial oxidative stress and their potential role in cardiovascular disease will be discussed.

Adult mosquito ecology in southwestern Georgia

Eva Whitehead, Odom School of Ecology
University of Georgia

Hosting Dept: Biology

Abstract:  Understanding the ecology of mosquitoes is important for implementing control measures and explaining mosquito-borne disease prevalence. I compared mosquito population dynamics to selected weather variables and land use/ cover in a longleaf pine dominated landscape on the Gulf Coastal Plain of Georgia. Important factors for determining mosquito presence/ absence were precipitation, temperature, humidity, and drought index. Aedes albopictus and Culex spp. mosquitoes were associated with sites that had the most anthropogenic influence, while Coquillettidia perturbans and Psorophora ferox were associated with natural land cover such as wetlands and forested land.  Arbovirus testing yielded one isolation of West Nile virus and three isolations of Potosi virus. This low arbovirus prevalence is likely due to the diversity of the wildlife in the area or factors related to the bird community, which typically serves as a reservoir for arboviruses. Examination of mosquito host-feeding patterns showed the mosquitoes collected predominantly fed on white-tailed deer.

Abstract:  In 2008 over 1,200 pedestrians were admitted to hospital emergency rooms directly as a result of injuries received when they were texting while walking. While the literature is extensive on the dangers of distracted driving, relatively little is known about distracted walking. Walking is potentially dangerous. In 2008, over 4,000 pedestrians died in a variety of accidents, mostly through hit-and-run accidents. It is not known the proportion of those dead who were involved in distracted walking. The purpose of the present talk is to examine issues in the cognitive processes of distracted activities, including walking while texting.

Spring Break Week

Dr. Christine James
Valdosta State University

Hosting Dept: Department of Philosophy and Religious Studies

Abstract:  Sonar, an acronym for “sound navigation and ranging,” refers to a variety of underwater imaging technologies. Recently, the United States Navy has met with some criticism for using long-range, low frequency sonar. Environmental groups have argued that the sound disruptions caused marine mammals, especially those capable of echolocation, to beach along the Pacific Northwest. The alternative type of sonar recommended by Greenpeace was “ambient noise”, “passive” sonar, also known as acoustic daylight imaging. The research team of Michael Buckingham at Scripps Oceanographic Institution in La Jolla, California made a careful study of acoustic daylight imaging sonar. In 2005, I made a research trip to Scripps and met with Michael Buckingham to ask him about the environmental and ethical implications of the various types of sonar. By 2006, the controversy over sonar technology was back in the courts, as the Navy sought to establish training grounds for new sonar operators in shallow waters of the Atlantic and off the coast of the southeastern United States. In the fall of 2009 appellate courts and the Supreme Court handed down decisions regarding the necessity of Naval training using sonar, the importance of impact statements (a form of precautionary science). There has also been a renewed investment in research at Scripps and Woods Hole on marine mammals potentially affected by sonar.

Philosophers of science analyze underlying principles and methods used by scientists. The case of sonar technology and its history provides a rich example for a variety of key questions in philosophy of science: subject-object relationships and perception, objectivity of scientific results, the use of instrumentation to augment human senses, and the broader issues of ethics and law.

This presentation will explore the most recent developments in the courts on this case study, and will analyze the approach that the Scripps research team has taken with regard to the Navy, the courts, and the environmentally concerned citizens invested in the issue.

Biological Control of Root-Knot Nematodes

Dr. Patricia Timper
USDA-ARS Crop Protection and Management Research Unit
Tifton, GA

Hosting Dept: Biology

Abstract:  Nematodes are roundworms, often microscopic, that are abundant in our environment. Some nematodes are parasites of animals (e.g., dog heart-worm) and plants, but most are non-parasites. Root-knot nematodes are plant parasites which cause significant yield losses in a wide variety of crop plants by damaging their root systems. I am interested in understanding how crop production practices such as tillage, crop rotation, and pesticide application influence natural biological control of root-knot nematodes. Organisms that prey on or parasitize nematodes are common in soil and sometimes these organisms reach levels that suppress populations of root-knot nematodes. My ultimate goal is to identify practices that enhance the activity of these beneficial organisms. In one study, I am testing the hypothesis that some crop rotations are better than others for increasing the abundance of Pasteuria penetrans, a bacterial parasite of root-knot nematodes. In another study, I am testing the hypothesis that application of a nematicide reduces the abundance of predatory nematodes (beneficial nematodes) and that this will lead to greater populations of plant-parasitic nematodes. The concern is that root-knot nematodes may rebound faster from the nematicide, because of their higher reproductive rate, than the predatory nematodes.

A COG in the fungal machine: How mutations in two COG proteins affect growth of Aspergillus nidulans

Dr. Sara Gremillion
Department of Biology
Armstrong Atlantic State University

Hosting Dept: Biology

Abstract:  Fungi are a diverse group of organisms that play many roles in nature including decomposers, mutualists and pathogens. Knowledge of how fungi grow will lead to a better understanding of the complexity of these ecologically important organisms. Using the fungus, Aspergillus nidulans, two genetically mutated strains were identified as having abnormal growth when grown at restrictive temperatures. The swoP1 (swollen cell) and podB1 (polarity defective) mutants produce conidia that swell to approximately 1.5 times the normal diameter. Conidia of swoP1 also produce abnormally wide hyphae and establish multiple points of polarity. Genes complementing the mutations of swoP1 and podB1 have genetic sequences homologous to COG4 and COG2, respectively. In mammals and yeast, COG2 and COG4 are part of an eight-protein structure called the COG (conserved oligomeric Golgi) complex associated with retrograde transport within the Golgi apparatus. Evidence from GFP-tagged COG2 indicated a Golgi protein localization. Protein overexpression studies provided evidence of intra-complex interactions between COG2 and COG4 as well as between COG2 and COG3. A promoter replacement strategy of COG2 and COG4 revealed that, when these proteins are produced in low numbers in the cell, fungal growth is only slightly, negatively affected. These studies provide support that the COG complex is an important component of normal fungal growth.

Last week of classes