SXCWC: Student Research Symposium

Sigma Xi Columbia-Willamette Chapter announces its second annual Symposium of poster papers by undergraduate and graduate students in the sciences, social sciences, and engineering. Students affiliated with any college or university in the Portland area are encouraged to submit abstracts. The deadline for abstract submission is March 31, 2006. The Symposium will be at the Smith Memorial Student Union on Friday, April 21, 2006. Several awards will be given for the best undergraduate and graduate posters. The symposium is open to the public from 1:00 to 5:00 pm, and admission is free.

Eligibility and rules: undergraduate and graduate students in the sciences, social sciences, and engineering, from any academic institution in the Portland area. All presentations are posters. A student cannot be lead author on more than one poster. Other students and faculty may be co-authors. The lead author must be present at the symposium to answer viewers' questions.

Abstract deadline: March 31, 2006
Abstract outline:
      Lead author (first, with * and email address)
      Co-authors
      Faculty advisor (last, with email address)
      Academic affiliations
      Departments or programs (to help with classification)
      Abstract text (maximum 250 words)
         Examples of abstracts

Abstract category: please choose the general area of the reported research from the following five categories:
      Behavioral and social sciences
      Biology
      Earth and environmental science
      Engineering, computer science, and mathematics
      Physics and chemistry

Posters: Each poster display space is 6' (horizontal) by 4' (vertical). For helpful advice on how NOT to present your research, we're grateful to the American Geophysical Union.

Symposium authors' timetable:
8:00 am: Smith Ballroom doors open.
10:00 am: deadline to display posters to be included in judging for awards.
1:00-5:00 pm: poster displays open to public.
The lead author must be present at the poster from 1:00 to 3:00 pm to answer viewers' questions.
4:15 pm: results of judging announced. .

Contacts for more information:
           Andrew Fountain
           Virginia Butler
           Mitch Cruzan
           Erik Sanchez
           Linda Mantel
           Scott Burns

Sigma Xi Columbia-Willamette Chapter sponsored its first annual Symposium of poster papers by undergraduate and graduate students in the sciences, social sciences, and engineering on Thursday, April 21, 2005. About 75 poster papers were presented, with primary authors from five colleges and universities in the Portland area (Portland State University, Lewis and Clark College, Oregon Graduate Institute of OHSU, George Fox University, and Linfield College). Several awards were given for the best undergraduate posters and several for the best graduate posters. The symposium was open to the public, and admission was free.

Symposium recognizes students' research
Smith Ballroom event displays over 80 students' scientific work
Lindsay Baltus
April 22, 2005

Josh Picotte (right) discusses his research on "leaf morphological adaptation during times of drought" with Linda Mantel.

Portland State hosted the first annual research symposium of Sigma Xi's Columbia-Willamette chapter yesterday.

Eighty students from PSU and four other universities in Portland gathered to exhibit posters on research in the areas of behavioral science, biology, earth and environmental science, engineering and applied science, mathematics and physical science (which includes physics and chemistry).

Students stood near their displays, chatting with Sigma Xi judges, as well as with students and interested professors.

Posters such as "Positive and Negative Predictors of Illness Disruption: A Prospective Study" and the "Effects of Density Mediated Destruction on Cod and Salmon Remains from a Prehistoric Archaeological Site In Southwest Alaska" filled the ballroom.

Catherine Dondlinger, one of only three students from Linfield College to participate in the symposium, was excited to share her poster on "Surface-Enhanced Raman Scattering on Novel Silver Nanoparticles in Solution and Immobilized on Glass Slides."

Her study could provide a more portable way to test river water onsite, eliminating the inconvenience of having to take samples back to a lab.

It can also be applied to forensics, detecting very small quantities of blood or drugs. Dondlinger explained that the world of Surface Enhanced Raman Scattering, (SERS), is an enigmatic one.

"We're still sort of trying to figure out exactly how SERS works, but my results were pretty exciting," she said.

Sigma Xi, the organization that supported the event, is a national honor society for scientists and engineers of every discipline. The society is over 100-years-old, and 198 Nobel Prize winners have been members. The Columbia-Willamette chapter, which provided the event's cash awards, also holds public lectures and assists in national science fairs on the middle school and high school level.

Nine judges from Sigma Xi were present at the symposium. Research projects were judged on visuals, oral presentation, and significance to the scientific world, and awards were given out at the end of the night.

Students received recognition in three categories: biology and behavioral science; earth and environmental science; and physical science, mathematics and engineering.

Each category had at least one undergraduate and graduate winner, and every winner received a certificate as well as a check for $100.

Award winners for Biology and behavioral science were: Laurie Dizney (graduate), Sharon Stanton (graduate), and Trieste Dobberstein (undergraduate).

For Earth and environmental science: Ashleigh Fines (graduate) and Summer Praetorius (undergraduate).

For Physical science, mathematics, and engineering: Jan Meiss (graduate), Emma Kuo (graduate), and James Mooney (undergraduate).

Student Research Conference at Sigma Xi National Meeting, Seattle, November 2005

Four Portland-area students who won awards at our chapter's April 2005 Student Research Symposium also presented their posters at the Sigma Xi National Meeting in Seattle on November 5. The Chapter paid part of their travel and registration expenses, using income from the MacCannell Endowment. All four posters were rated very favorably by the national judges.

Healthy ecosystems are good for your health

Laurie J. Dizney, Philip D. Jones & Luis A. Ruedas

Portland State University, Dept. Biology (LJD, PDJ, LAR), Mus. Vert. Biol. (LAR); Portland, OR, USA; Oregon Public Health Lab., Portland, OR, USA (LJD)

In recent years, there has been a surge of newly emerging infectious diseases affecting humans, such as Ebola, West Nile Virus, SARS, Avian Influenza, and Hantavirus. These are all zoonotic diseases—diseases carried by wildlife—that periodically spill over and spread in human populations. As human populations expand and come into more frequent contact with wildlife, these spillovers will inevitably increase in number. Can such events be predicted or prevented? This research investigates the inverse relationship between natural biodiversity and the incidence of zoonotic disease, specifically Hantaviru s . The three–year study is being conducted in five natural areas around Portland, OR that vary in size and vegetation. Small mammals are trapped using a web sampling grid, in order to achieve accurate density measurements, as well as consistency with other studies. Blood samples are tested for hantaviral antibodies using ELISA. Population density is calculated using the program DISTANCE. Statistical analyses are undertaken using SAS and SPSS. We have sampled 5000 specimens and found Hantavirus–positive deer mice (Peromyscus maniculatus), the natural host, in all parks. Using non–linear regression, we have found a strong significant negative relationship between site biodiversity and percent infection rate: that is to say, as biodiversity decreases, the prevalence of Hantavirus in the ecosystem increases, and exponentially so when diversity becomes very low. This result has clear implications for both human health and conservation efforts: by managing natural areas to maximize biodiversity, zoonotic diseases and their associated risks to humans can be minimized.

The electrochemical fabrication of ZnO nanostructures: light-emitting diodes and solar cells as two applications

Jan Meiss, Robert Word and Rolf Könenkamp, Physics Department, Portland State University

Presented is the process of electrochemical deposition of ZnO nanostructured materials in aqueous solutions at temperatures between 70° C and 85° C on different substrates, and device fabrication using electrodeposited materials.

As a result of the electrochemical deposition process, different materials with characteristic structures on the nano- and micrometer scale were obtained: grown from additive-free ZnCl2 solutions were free-standing hexagonal nanowires or nanorods. By adding the organic red dye eosinY to the solution, a sponge-like interconnected nanoporous material was obtained. The created materials were studied using high-resolution scanning electron microscopy and transmission electron microscopy.

Two devices, a light-emitting diode and a solar cell, were fabricated using these ZnO structures as electrically active components. By using spincoated polystyrene for encapsulation and insulation, a conductive polymer as p-type hole transporting material and a thin gold film as anodic back contact, prototype working devices could be constructed and were studied and characterized.

Altogether, it could be shown that electrodeposition is an excellent tool for the creation of highly crystalline and structured materials as a comparatively inexpensive, low-temperature process. The materials are well-suited for a variety of applications and devices, as could be shown qualitatively in the current research.

A sediment record of bottom currents in the North Atlantic since the last ice age

Summer Praetorius, Jerry McManus*, Christina Hulbe, Geology Department, Portland State University and *Woods Hole Oceanographic Institute, (Summer Student Fellowship).

North Atlantic Deep Water (NADW) is a major component of the ocean’s thermohaline circulation, which is strongly linked to climate via the sea-to-air heat transfer that occurs as warm equatorial waters are transported to the high latitudes. Changes in the NADW have been implicated in abrupt climatic shifts in the past. Here we use the grain size distribution of deep-sea sediments accumulating in the North Atlantic as a proxy for current strength in order to compare changes in circulation with climate variations during the last 23,000 years. Site 984 (61°N, 24°W, 1648m) is well situated to monitor both the modern outflow of deep water over the Iceland-Scotland ridge and the intermediate depth waters of the glacial period. The sediment record indicates that the bottom current strength was of similar magnitude during the last glacial maximum and Holocene, while the deglacial period displays a decrease in current strength. This suggests that freshwater from melting glaciers can influence the rate of the overturning circulation. Current strength reached a minimum during the Younger Dryas cold oscillation, and then increased to a maximum at the time of rapid warming at the onset of the Holocene, supporting the hypothesis that shifts in circulation may induce or amplify abrupt climate changes.

The ecological relationships of dwarf mistletoe and fire in mature ponderosa pine forests of Oregon

Sharon Stanton, Dr. Keith Hadley, Robert Tinnin, Biology PhD Program, Portland State University

This research focuses on the fire ecology of old-growth ponderosa pine forests (Pinus ponderosa) infested with parasitic dwarf mistletoe (Arceuthobium campylopodum). Few studies have examined the impacts of dwarf mistletoe on the structure and function of ponderosa pine forests, and the relationships between dwarf mistletoe and other disturbances, especially fire, are poorly documented. The objective of this research is to increase our knowledge of the complex ecological relationships among dwarf mistletoe, host tree growth, and fire dynamics. Fuel composition, stand structure, and mistletoe abundance were sampled in mature ponderosa pine stands located in Crater Lake National Park and Newberry Volcanic National Monument. Fire behavior was monitored in fourteen plots during fall season prescribed burns at Crater Lake National Park. Fuel accumulation and post-fire mortality were monitored following the prescribed burns. Analysis of variance and GIS models reveal weak relationships between mistletoe infection level and fuel biomass. Ordination analyses suggest that tree density and species composition strongly influence fuel composition and fire behavior, while dwarf mistletoe infection has a weak relationship with fuels and fire intensity. Areas with severe dwarf mistletoe infestation recorded the highest temperatures during prescribed burns and have higher rates of fuel accumulation following fire. These results suggest there is a threshold infestation level in ponderosa pine forests, beyond which the high density of dwarf mistletoe alters fire ecology. The ecological role of mistletoe in shaping fire regimes and post-fire recovery is complex and unpredictable at the landscape scale.