College of Sciences E-newsletter

July 2007

In this issue:

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University of Sonora (Hermosillo, Mexico) and UNLV Sign Cooperative Agreement

On May 30, 2007 UNLV President David Ashley and University of Sonora (Hermosillo, Mexico) Rector Pedro Ortega Romero signed a cooperative agreement designed to foster increased collaboration between the two universities, including exchanges of undergraduates, graduate students, and faculty members. Under the three-year agreement, UNLV will develop joint academic and research programs with La Unison to promote scholarship in the areas of interest to both institutions. Activities outlined in the agreement include exchanges of academic personnel for the purpose of study and research as well as the exchange of scholarly information between students and faculty.

Other Sonora officials who visited UNLV and toured both College of Sciences' facilities and other campus venues included Herberto Grijalva Monteverde, vice-rector; Enrique Fdo. Velazquez Contreras, provost; Jose Cosme Guerrero Ruiz, professor of agriculture; and Jose Luis Garcia Ruiz, director of international programs. Earlier this year a group from UNLV visited the University of Sonora campus to initiate discussions.

Ron Yasbin, dean of UNLV's College of Sciences, says the partnership will not only foster cross-cultural collaboration but will help leverage the research strength of each institution, particularly in the area of the life sciences.  "Our universities share many similar characteristics, with each located in a growing urban setting and surrounded by arid lands," said Yasbin. "I’m excited to embark on this collaborative teaching and research effort that will serve to improve the work of students, faculty, and staff at both universities." This summer, two students from La Unison will participate at UNLV in a four week research project, during which they will study under professors Dale Devitt, director of UNLV’s Center for Urban Horticulture and Water Conservation (CUHWC), and Eduardo Robleto, a microbiologist who specializes in environmental microbiology and molecular biology.

Read the full text.

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National Science Foundation (NSF) Grant Awarded: "An Experimental Test of Senescence and Aging Mechanisms in a Free-living Organism," ($667,000)

Two faculty members in the School of Life Sciences, Michelle M. Elekonich, Ph.D. (principle investigator) and Stephen P. Roberts, Ph.D. (co-principle investigator) have received an NSF Grant designed to explore the biological factors relating to aging. This grant ($667,000), “An Experimental Test of Senescence and Aging Mechanisms in a Free-living Organism,” begins on August 1, 2007 and runs for three years.

Abstract: An important biological question is how age and behavior interact to determine senescence (the deterioration of physiological performance) and longevity. This research will address this question, and in doing so test major models of aging theory, by experimentally manipulating the onset, intensity and duration of a metabolically-expensive natural behavior (foraging) in a free-living organism (honey bees) whose social complexity rivals our own. The effects of these manipulations, as well as age, will be determined for impacts on locomotor ability, muscle performance, oxidative damage, anti-oxidant capacity and longevity. The oxidative-stress theory of aging and senescence predicts that early onset, high intensity and/or long duration foraging effort will accelerate senescence and decrease longevity, and that late onset, low intensity and/or short duration foraging should have the opposite effects. This research takes advantage of the experimental tractability of the honey bee model system and integrates molecular, genetic, physiological, and behavioral perspectives to advance the understanding of factors that limit lifespan. This project will promote teaching, training, learning and the participation of underrepresented groups via (1) the inclusion of a postdoctoral scholar, a graduate student, a technician and undergraduates (many of whom are members of underrepresented groups and currently working in the laboratories of the PI and co-PI), and (2) the integration of the project’s findings and perspectives into the diverse array of university courses, K-12 presentations and outreach opportunities for the general public that are routinely offered by the PI and co-PI.

Read the UNLV Press Release.

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UNLV Researchers To Study Restoration Of Native Vegetation After Wildfires: Research Will Help Land Managers Control Post-Fire Invasion Of Exotic Species ($179,000

Researchers at UNLV’s Public Lands Institute (PLI) and School of Life Sciences have been awarded a two-year, $179,000 grant from the U.S. Department of Interior’s Joint Fire Science Program to identify native species that will help improve the restoration of arid lands following uncontrolled wildfires.

PLI and School of Life Sciences Assistant Research Professor Scott Abella and School of Life Sciences Professor Stanley Smith will use the funding to identify native species that can be easily established and strongly resistant to exotic grass invasion. The collaborative research and land management team also includes Alice Newton, vegetation management specialist at Lake Mead National Recreation Area, and Christina Lund, botanist with the Las Vegas Field Office of the Bureau of Land Management.

Wildfires are occurring at greater frequency on Southwestern arid lands, such as the Mojave Desert in Southern Nevada. In 2006, wildfires burned 1.3 million acres in Nevada. The scars of the post-burn landscape often remain visible as efforts to reestablish native vegetation fail, while non-native grasses continue to grow and serve as fuel for the next lightning- or human-sparked wildfire.

This research addresses a critical issue for desert ecology in the Southwest and is of national interest. “We’re faced with the challenge of exotic annual grasses fueling wildfires and then becoming even more abundant after the fire,” says Abella. “We need to break the unnatural exotic grass-wildfire cycle. When native plants are reliably established, they can reclaim burn areas and be competitive in post-fire environments typically dominated by exotic annual grasses.”

Researchers will examine the establishment and competitive abilities of nine native perennials at a nursery facility at Lake Mead National Recreation Area and at six desert sites within Lake Mead and adjacent to Red Rock Canyon National Conservation Area. Recommendations will be presented to land managers and scientists in late 2009. The findings will be disseminated through field trips, conferences, workshops, web sites, publications and technical articles.

The Public Lands Institute was initiated in 2005 to work in collaboration with federal, state, and non-profit partners to create new knowledge, advance technology, improve education, and engage the community to enhance public lands stewardship. More information about the institute is available at http://publiclands.unlv.edu.

Read the UNLV Press Release.

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Research Award From The National Research Initiative (NRI) Competitive Grants Program, U.S. Department of Agriculture’s Cooperative State Research, Education, and Extension Service (CSREES) ($295,000)

Jeff Qingxi Shen, School of Life Sciences, has received a $295,000 three-year research award from the National Research Initiative (NRI) Competitive Grants Program, of the U.S. Department of Agriculture’s Cooperative State Research, Education, and Extension Service (CSREES) to support his research on rice, an important food crop and a significant source for biofuel production. This project, “The Role of a Rice WRKY Gene in Suppressing Gibberellin Responses in Aleurone Cells of Cereal Grains, “

Abstract: The "Green Revolution", i.e., the huge increase in grain yields after the 1960s, is the result of the introduction of new varieties of grain crops. Recent studies indicate that these varieties are mutants for the biosynthesis of or responses to a plant hormone called gibberellin (GA). The overall goal of our research is to understand how GA signals are perceived by plants to regulate their growth and development. Expression of genes at right time and with right amounts is the molecular foundation of these processes and is controlled by a set of proteins called transcription factors, which are analogous to fingers operating a light switch.  In general, there are two types of finger proteins: repressors that are analogous to the brakes of a car, and activators that serve as the car’s “accelerator pedal.” The combination of repressors and activators controls the level and timing of gene expression. In this study, we will study the structure of a brake, i.e. the OsWRKY71 repressor. How is it removed by GA so that genes can be expressed (a car can move)?   How does it work with an activator (accelerator pedal) to control levels of gene expression (speed of a car)? The knowledge gained from this study will make it possible to manipulate grain quality, to alleviate major seed crop losses due to pre-harvest sprouting and increase biomass production.  This project is in line with USDA Strategic Plan Goals 1 and 3: to enhance economic opportunities for agricultural producers and enhance the protection and safety of the nation's agriculture and food supply. It will also contribute to increasing the yield of biofeul production (by increasing biomass production).]

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National Science Foundation Grant ($950,000): Studying Gene Expression Of Desert Fruit Flies

Researchers at the University of Arkansas and University of Nevada-Las Vegas (Allen Gibbs, professor, school of life sciences) will study the genetics of fruit flies in desert habitats to determine how they developed the ability to survive under stressful conditions. Approximately 40% of the earth's landmass is classified as arid or semi-arid, and this percentage is expected to increase as a result of global climate change and human activity.  A direct approach to understanding how life on earth may adapt to these changes is to study desert organisms that already inhabit arid regions.  This requires an integrated analysis of physiological, biochemical and genetic responses to the environment.  An ideal system for study includes a desert insect, Drosophila mojavensis (fruit fly), and the host plants it uses to survive in the southwestern deserts of North America.  The ecology and physiology of Drosophila mojavensis have been well studied, and it is the only desert animal whose entire genome has been sequenced.  These factors make it uniquely suitable for the study of genetic adaptation to arid habitats.  This research will use modern techniques to study how environmental stresses (heat, lack of water, diet) affect the expression of all of the genes in Drosophila mojavensis under controlled laboratory conditions and in nature.  This information will be integrated with physiological and biochemical studies to understand how these genes interact to allow this insect to survive extreme environmental conditions.  The genes identified in these experiments will serve as candidates to predict how well other species can adapt to arid conditions within their lifespan and over generations.  Understanding how these interacting genes respond to stressful desert environments will also help us predict the survival of beneficial insect species, such as crop pollinators, as climate changes in the future.  This research represents collaboration between two laboratories and will provide integrated research training to undergraduates, graduate students and a post-doctoral researcher.

Science Daily — Researchers at the University of Arkansas and University of Nevada-Las Vegas will study the genetics of fruit flies in desert habitats to determine how they developed the ability to survive under stressful conditions.

host cactus

One of the host cactus for Drosophila mojavensis. Researchers at the University of Arkansas and the University of Nevada-Las Vegas will study the genetic variation of these tiny flies in their native habitat. (Credit: William Etges

William J. Etges, professor of biological sciences at the University of Arkansas, and Allen Gibbs, professor of biological sciences at the University of Nevada-Las Vegas, have received $950,000 for three years from the National Science Foundation to study the genetic response of the desert fruit fly, Drosophila mojavensis, to environmental stresses in the wild.

Most fruit flies live in mild climates, but a number of species such as D. mojavensis have colonized the desert, using fermenting cactus and surviving in high heat and low water conditions. The researchers plan to identify genes that have helped the fruit flies adapt to these harsh conditions. The genes identified may serve as candidates to predict how well other species can adapt to arid conditions within their lifespan and over generations. This takes on greater importance as arid and semi-arid environments increase globally.

Further, scientists have used fruit flies for genetic model systems in the laboratory for years. Because fruit flies have diversified into thousands of species, reproduce quickly and create many generations in a short time, scientists use them to study evolution, population genetics and diversification. However, laboratory work does have limitations, Etges said. “No one knows if the processes found in the lab are the same in the real world,” he said.

Since the genome of D. mojavensis has been sequenced, Gibbs and Etges will use DNA micro arrays, sometimes called “gene chips,” to determine relationships between various genes and environmental conditions in fruit flies found in the wild. A microarray contains thousands of tiny spots on a small slide, each spot representing a different gene in the fruit fly genome.

The researchers will use sensors to monitor temperature and humidity at different desert locations, and they will collect fruit flies from these locations at different times of the year under varying conditions of temperature and water availability. Then they will extract the cellular RNA from the animals, which supplies the code for all the DNA that was currently being expressed by the fruit fly. They transcribe the RNA into single-strand DNA, then wash the microarray with the fruit fly DNA solution. Copies of specific genes in the solution will hybridize with the genes on the microarray, which are modified with a fluorescent dye easily detected by the researchers. The microarray then provides a “map” of what genes are expressed and which ones are not under given circumstances. “We can look at flies at different life stages and see how genetic activity changes,” Etges said.

Determining correlations between environmental stresses and expressed genes does not necessarily indicate a cause and effect, Etges pointed out, but it does give researchers an idea of what genes they should focus on. Etges has studied the ecology, physiology and genetics of fruit fly populations for more than 20 years. The information gained in this study will add to the body of knowledge about these creatures. Integrating techniques such as microarrays into long-term studies eventually will help researchers determine the genetic process of adaptation and how new species are formed. “This is the beginning of a long series of investigations,” Etges said. Once Gibbs and Etges have determined the genes that respond to stress in D. mojavensis, they can begin to compare the responses to those found in close relatives and look for differences.

“Eventually we want to know about the larger-scale patterns that explain how species are formed,” said Etges, a professor in the J. William Fulbright College of Arts and Sciences.

Note: This story has been adapted from a news release issued by University of Arkansas, Fayetteville.


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“Energetic Homeostasis During Metamorphosis,” National Science Foundation (NSF) Grant ($518,846)

School of Life Sciences associate professor Deborah Hoshizaki, principal investigator, and assistant professor Allen Gibbs (co-principal investigator) have received a three-year, $ 518,846 grant from NSF to study energetic homeostatis during metamorphosis. Metamorphosis is a remarkable period during insect development that marks the transition from larval to adult life. The transformation of the animal during the non-feeding pupal stage is characterized by the destruction of most larval tissues and by the construction of the adult. The principle energy reserves to fuel this process reside in the pupal fat cells. The origin of these cells is unique, as they are larval fat cells which escape destruction. Upon completion of pupal development, these larval-derived fat cells continue to be an energy reservoir for the young adult. The overall goal of the research is to understand the role of the fat cells in regulating pupal development at the organismal, developmental, and cellular level. By genetic manipulations, the nutritional content of larval fat cells will be altered and the mechanisms by which the pupa adjusts to fulfill its energetic needs examined, and the energetic consequences of pupal development on the young adult determined. Genes from two cellular pathways, Ecdysone and Insulin signaling, have been identified as likely candidates important in metabolic regulation. This project will test the hypothesis that fat cells respond to the metabolic needs of the pupa and, through input from Ecdysone and Insulin signaling, monitor and regulate the release of energy to support development, while still maintaining energy reservoirs necessary for survival of the young adult. This metabolic regulation is essential for successful metamorphosis. This is a collaborative proposal between two labs with complementary expertise in developmental genetics and organismal physiology. Both labs have vigorous undergraduate research programs that have resulted in numerous conference presentations and co-authored journal articles by undergraduates. These activities will continue under this award, as will graduate training which will emphasis an interdisciplinary approach and highlight the use of cellular, molecular, and genetics techniques in understanding organismal physiology.

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President’s Research Initiative (PRA) Award

“It’s Not the Age, It's the Mileage: Influences of Activity on Aging, Longevity and Muscle Function, “ Michelle Elekonich (team leader), School of Life Sciences.

Team members: Dr. Stephen Roberts, Dr. Jason Williams, Dr. Christian Ross

Total Funding:  $49,961

Abstract: Although millions of dollars are annually spent on aging and stress research, there are precious few comprehensive studies that attempt to experimentally link (1) the onset, intensity and duration of natural behaviors, (2) senescence (the age-related decay in functional performance) and longevity and (3) the cellular and physiological mechanisms that mitigate age related stress. Ongoing research in my laboratory and that of my collaborator Dr. Stephen Roberts takes just such an approach by focusing on how age, gene expression and behavior interact to affect senescence and lifespan in an organism whose social complexity rivals our own, the honey bee (Apis mellifera). On the genetics front, we have focused to date on several stress and aging related candidate genes and their protein products: catalase, superoxide dismutase and Hsp70. The actual cellular response is likely to involve many more genes and cellular signaling pathways. The research proposed here will make use of newly available microarrays for the full honey bee genome to identify entire groups of genes involved in stress and aging. UNLV has all the necessary equipment to do this research between the Genomics, Bioinformatics and Sequencing Centers. However, there is no published research with microarrays from UNLV, and our efforts to gain panel federal level funding require that we demonstrate our capacity to do this work at UNLV.

The honey bee is an ideal model for studies of behavioral development and aging. In addition to possessing a fully sequenced genome (Honey Bee Genome Constortium 2006), its age, behavior, aerobic expenditure and associated damage, functional senescence and lifespan (due to caste or amount of foraging) can be manipulated independently. Only a partial set of these manipulations can be successfully performed with fruit flies, nematodes and mice (Arking et al 2002, Barger et al 2003, Guarente & Kenyon 2000, Kenyon 2001, Takahashi et al 2000, Tatar et al 2003, Wood et al 2004) and practically none can be accomplished for these model organisms when they are outside of the laboratory and in natural environments. Because flying honey bees have the highest aerobic metabolic rates ever measured in any animal (Roberts & Harrison 1999), their mechanisms for mitigating oxidative damage may be critically important. Age related honey bee behaviors are highly stereotypical, easily quantified and can be studied in their natural environment (Winston 1987). The honey bee system is highly tractable, with well established manipulations to separate age from behavioral state, limit or prolong naturally occurring behaviors (especially flight), measure metabolic and functional capacity and gene expression (Roberts & Elekonich 2005). Furthermore, a single hive contains upwards of 40,000 related individuals allowing easy collection of large samples. Instrumental insemination is also well developed in honey bees allowing researchers to control the genetics of a colony. Finally, the relatively short lifespan of female worker bees in contrast to the longer lifespan of queens suggests that bees may be particularly well suited to investigations of the cellular mechanisms underlying individual differences in the rate of aging (Carey 2001).

 

 

The proposed research will provide important insight into how age, gene expression and functional capacity interact with behavior to determine longevity in a species whose social complexity rivals our own, and should generate strong interest from members of the scientific community integrating ecological, evolutionary, functional, genomic and socio-biological approaches. One of our team members, Dr. Jason Williams is supported on a NIH NRSA from the Institute of Musculoskeletal and Skin Diseases to pursue further measures of the antioxidant response and muscle damage. It is our expectation that with the additional pilot data from the research proposed here we would be able to submit a RO1 to this panel as they are clearly receptive to the honey bee model. We also expect that this research will be fundable through the National Institute of Aging and The National Institute of Environmental Health Sciences which is interested in responses to environmental stressors.

“Confocal Microscopy”

Helen Wing (Life Sciences), Ernesto Abel-Santos (Chemistry) and Eduardo Robleto (Life Sciences) were awarded $6,000 to cover costs associated with graduate student use of the confocal microscope housed in the Nevada Center for Biological Imaging. Graduate students in each of these laboratories study microbial interaction with either plant or animal cells. These interactions have important implications in the fields of medicine, veterinary science, and agriculture.

The Wing Laboratory studies the bacterial pathogen Shigella flexneri, the casual agent of bacillary dysentery. Dr. Wing’s lab is interested in Shigella proteins that are found in the outer membrane of this bacterial pathogen. These proteins lie at the microbe: host interface and are likely to be involved in the modulation of the host cell, leading to pathology in the infected host. Graduate students working with Dr. Wing will use the confocal microscope to determine the location of a virulence protein in the Shigella outer membrane

The Abel –Santos Laboratory studies the interactions between human macrophages and anthrax spores. Anthrax is caused by the bacterial pathogen Bacillus anthracis. Under harsh conditions (starvation, extremes heat, radiation, or exposure to toxic chemicals) this bacterium forms a highly resistant spore, which protects the bacterium until favorable conditions return.  Following human inhalation, B. anthracis spores are phagocytosed by macrophages in the lungs of infected hosts (11). Graduate students in Dr. Abel-Santos’s laboratory will investigate specific details of these events using the confocal microscope.

The Robleto Laboratory uses Pseudomonas fluorescens, a soil and roots denizen, to study adaptations of bacteria growing in close proximity to plant roots (the rhizosphere; (20)).  P. fluorescens has been used for biocontrol of specific plants and as a plant growth promoter (1).  Use of the confocal microscope will allow graduate students in Dr. Robleto’s group to study the specific interaction of P. fluorescens and the roots of the common bean, Phaseolus vulgaris.

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“Effects of Space Flight and Hypergravity on Energy Storage in a Model Organism (Drosophila melanogaster),” NASA Nevada Space Grant Consortium ($20,000)

School of Life Sciences associate professor Deborah Hoshizaki, principal investigator, and assistant professor Allen Gibbs (co-principal investigator) have received a $ 20,000 grant from the NASA Nevada Space Grant Consortium to investigate the effects of space exploration on astronauts, one of the strategic goals outlined by NASA for 2007. Recent studies have shown spaceflight and various stresses associated with it, have effects on the distribution and number of white blood cells, decrease the proliferative responses and cytokine production of lymphocytes, and adversely affect cell-mediated immunity. These findings suggest that space flight decreases the body’s ability to fight infection. Hoshizaki and Gibbs will collaborate with Dr. Deborah Kimbrell (University of California, Davis) in experiments using the fruit fly, Drosophila melanogaster, to understand how the immune system responds to infection when exposed to a space environment. The role of the Hoshizaki and Gibbs laboratories in this collaboration is to measure the energy stores of the animal as an indicator of general health and to characterize the fat body, the primary energy storage and immune response organ, by histochemical staining. The proposed project will utilize Drosophila reared on the recent space shuttle flight initiated on July 4, 2006. Because of the shortage of room on the shuttle flight and limitations in experimental manipulations, the space flight studies are limited to the growth of Drosophila in space, and the subsequent infection of Drosophila on the ground. These experiments will provide insights into the capacity of the immune system to develop normally in space and to respond to post-flight infection.

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Exploring The Fundamental Question Of How Radiation Affects The Decomposition Of Explosives: ISS Summer Research Program

UNLV researchers are addressing critical homeland security issues this summer as part of a unique research program sponsored by the Institute for Security Studies (ISS) and Division of Educational Outreach.  The ISS Summer Research Award Program provides an opportunity for UNLV faculty to study security-related topics requested by local and federal government agencies. Representatives from the Department of Homeland Security, Department of Defense and Las Vegas Metropolitan Police Department collaborated with the ISS to determine a list of specific research areas deemed critical to advancing our understanding of homeland security.

“This program is an attempt to expand the research connections between UNLV and the local and federal government,” said Scott Smith, executive director of the ISS. “By using the scholarly resources of UNLV to shed light on the concerns of these agencies, we’re proactively forming partnerships that will ultimately benefit the security of our community and our nation.”

Through a call for proposals, three UNLV faculty members were funded a total of $60,000 to conduct research from June through August, with the results to be presented to the requesting agencies in the fall.

Health physics associate professor Phillip Patton is examining the risk to humans associated with high-energy X-ray equipment proposed to detect weapons of mass destruction at U.S. entry ports. By developing a unique computer X-ray modeling program, Patton will determine what radiological risks exist to those accidentally exposed as well as the optimal X-ray spectrum necessary for imaging incoming containers.

Assistant professor of physics Michael Pravica is exploring the fundamental question of how radiation affects the decomposition of explosives. By analyzing the decomposition rate of a single crystal of secondary explosive in the presence of a synchrotron beam, Pravica is hoping to understand how energy and crystalline orientation contribute to the crystal’s destruction. Learning about why explosives detonate, decompose and deflagrate is an essential step in understanding how to safely detect and neutralize explosives.

School of informatics assistant professor Ju-Yeon Jo is conducting a national survey of civilian-owned companies that offer services in digital forensics. Jo will assess the current state of the digital forensics workforce—how it is trained, what tools are available, and how various labs throughout the country collaborate with government agencies. Jo will also examine the current impact of the outsourcing trend in digital forensics and how the shortage of investigators can be overcome.

The ISS plans to continue and expand the Summer Research Award Program each year as part of its mission to combine the research capabilities of UNLV with outside agencies to address contemporary security concerns. Results from the three projects may serve topics for future ISS Security Forums.

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Josh Muterspaw Scholarship Endowment

The University of Nevada, Las Vegas Foundation has established the Josh Muterspaw Scholarship Endowment Fund for the College of Sciences thanks to a gift and pledge from the Andre Agassi Charitable Foundation.  The Foundation was founded in 1994 by tennis legend Andre Agassi to provide recreational and educational opportunities for at-risk children.

This fund is established to honor the memory of Josh and Jason Muterspaw, childhood friends of Agassi who shared his love for the game of tennis. Josh succumbed to cancer in 1994 at the age of 18 and Jason died in an automobile accident in 2000. Funds raised through the Muterspaw Championships national junior tennis tournament, hosted by the Andre Agassi Charitable Foundation, will be contributed to the endowment fund. The purpose of this fund is to provide assistance for deserving students with financial need who are pursuing degrees in the College of Sciences.

When the endowment matures, scholarships will be awarded to undergraduate students whose qualifications include a 3.0 GPA and who major in the College of Sciences. Preference will be given to students who are planning to pursue a career in the medical and/or health care fields.

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Geoscience Assistant Professor Adam Simon's Research on Volcanoes Could Help to Harness Cleaner, Renewable Energy in Nevada

Watch the video of geoscience assistant professor Adam Simon explaining how his research with active volcanoes in Kamchatka, Russia could help us to harness cleaner, renewable energy sources here in Nevada.  Video courtesy of UNLV Campus Connections, a television show produced by the office of Public Affairs and UNLV-TV: 

 

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KNPR Radio Interview: The Legacy of Nikola Tesla with Michael Pravica

Assistant professor of physics and astronomy Michel Pravica participated in an interview on KNPR Radio, reflecting on the life and legacy of inventor Nikola Tesla. Pravica recently delivered a University Forum lecture on this topic to a packed audience.

Listen to the KNPR interview.

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Climate Change Linked To Origins Of Agriculture In Mexico

UNLV assistant professor of geoscience Matt Lachniet is a member of the team that has published its findings in the Proceedings of the National Academy of Sciences online.

Science Daily — New charcoal and plant microfossil evidence from Mexico's Central Balsas valley links a pivotal cultural shift, crop domestication in the New World, to local and regional environmental history. Agriculture in the Balsas valley originated and diversified during the warm, wet, postglacial period following the much cooler and drier climate in the final phases of the last ice age. A significant dry period appears to have occurred at the same time as the major dry episode associated with the collapse of Mayan civilization, Smithsonian researchers and colleagues report in the Proceedings of the National Academy of Sciences online.

Iguala Valley

Cores from Laguna Tuxpan in Mexico's Iguala Valley, provided evidence for maize and squash cultivation along its edges by ~8000 B.P. and for the major dry event between 1800 and 900 B.P. (Credit: Ruth Dickau)

"Our climate and vegetation studies reveal the ecological settings in which people domesticated plants in southwestern Mexico. They also emphasize the long-term effects of agriculture on the environment," said Dolores Piperno, curator of archaeobotany and South American archaeology at the Smithsonian's National Museum of Natural History and the Smithsonian Tropical Research Institute in Panama.

Piperno's co-authors include Enrique Moreno and Irene Holst, research assistants at STRI; Jose Iriarte, lecturer in archaeology at the University of Exeter in England; Matthew Lachinet, assistant professor at the University of Nevada in Las Vegas; John Jones, assistant professor at Washington State University; Anthony Ranere, professor at Temple University; and Ron Castanzo, research collaborator at the National Museum of Natural History.

Pollen of Podocarpus, a conifer now found primarily at higher elevations, is common in the oldest strata of sediment cores taken from lakes and a swamp in the central Balsas watershed. Along with pollen from grasses and other dryland plants, the Podocarpus indicates the environment encountered by humans at the end of the last ice age (14,000-10,000 B.P.) was drier and 4 or 5 degrees Centigrade cooler than it is today.

The Balsas valley is one of the most likely sites for the domestication of corn (Zea mays) from its wild ancestor, teosinte (Zea mays ssp. parviglumis) because populations of modern teosinte from that region are genetically closest to maize. As the lakes formed beginning around 10,000 B.P., they became magnets for human populations who exploited the fertile soils and rich aquatic resources the lakes contained. The researchers found prehistoric pottery shards and other artifacts in sediments at the edges of the lakes. At one lake, phytolith data shows that maize and squash were probably planted at the fertile edges by 8000 B.P. Pollen from teosinte is indistinguishable from that of maize, but Zea pollen is consistently present in the cores since the end of the last ice age.

Pollen and phytoliths from weeds associated with crop plants become plentiful in the cores at roughly 6300 B.P Charcoal associated with agricultural burning practices also is abundant at that time. Between 1800 B.P. and 900 B.P., a major drying event occurred, corresponding to the time when a drought occurred in the region of the Classic Mayan civilization. This evidence shows that even during the Holocene, severe, short-term climatic oscillations occurred that may have had considerable importance for social change.

"We continue to find that tropical forests played a much more important role in the origin of agriculture in the New World than was once thought," Piperno said. The team will publish evidence from corresponding archaeological excavations of nearby caves and rock shelters that will begin to fill in cultural information that accompanied these changes and date them more precisely.

Piperno, D.R., Moreno, J.E., Iriarte, J., Holst, I., Lachniet, M., Jones, J.G., Ranere, A.J., and Castanzo, R. 2007. Late Pleistocene and Holocene Environmental History of the Iguala Valley, Central Balsas Watershed of Mexico. Proceedings of the National Academy of Sciences online. Funding for this study was provided by a grant from the Andrew W. Mellon Foundation and the Smithsonian Tropical Research Institute and National Museum of Natural History.

Note: This story has been adapted from a news release issued by Smithsonian Tropical Research Institute.

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New School and Department Chairs

The College of Sciences wishes to recognize and thank three individuals who have concluded their tenures as school and department chairs: Carl Reiber, School of Life Sciences, Spencer Steinberg, Chemistry, and Wanda Taylor, Geoscience. Three colleagues who have agreed to assume these responsibilities are: Dennis Bazylinski, School of Life Sciences; Dennis Lindle, Chemistry, and Michael Wells, Geoscience.

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Summer Science Institute for Middle School Science Teachers

On August 13, 2007, a group of UNLV faculty, staff, and students including Helen Wing, Mark Buttner, Patricia Cruz, Shawn Gerstenberger, Eun-Hae Kim, Linda Stetzenbach, Shyama Malwane will host approximately 60 Las Vegas 6th grade science teachers for a workshop entitled "How Do We Stop the Spread of Disease?" Cheryl Wagner of the CCSD is coordinating this event.

The workshop will assist teachers in gaining the scientific information necessary to apply to their school curriculum. Teachers will engage in both hands-on research experience and attend expert interactive lectures/discussions about such topics as disease investigation, research, public information, etc.

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REU Summer 2007 Students Arrive on Campus

Sponsors of the Southern Nevada Summer Research Experience Programs include: UNLV (HiPSEC) High Pressure Science and Engineering Center; US DOE US DOD-MURI; National Science Foundation - EPSCoR Program; National Institute of Health - (NBRIN); Nevada Biomedical Research Infrastructure Network; Desert Research Institute; University of Nevada Reno; and the UNLV College of Sciences. Dr. Neil Smatresk, Executive Vice President & Provost joined the students and faculty to offer a warm welcome to UNLV.

Student participating in this years expanded program are: John Badasci, Jason Baker, Cameron Ball, Kathryn Ball, Lauren Besquillo, Kyle Bowen, Lacie Brownell, Daniel Bricker, Brad Clarke, Kelsey Clements, Kyle Costa, Shipra De, Franco Diaz, Damian Durruty, Tamara Elliott, Crystal Erickson, Kimberly Franco, Amanada Gordon, Nick Gordon, Lora Griffin, Joy Hallmark, Toni Hodges, Paul Howse, Christina Jacovides, Noah Kapley, Dwight Kieffer, Tao Kim, Robert Kobey, Jeffrey Kroll, Amad Martin, Yalemi Morales, Joshua Olitzky, Jerralie Orwig, Vishal Patel, Zachary Quine, Momina Razaq, Stephane Ricoult, Lawrence Selvy, Annalee Sendis, Wendy Seto, Patrick Sims, Jennifer Smith, Patricia Sotolongo, Aynsley Sutherland, Tara Sutherland, Michael Treat, Anisa Valinia, and Monley Zheng.

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Lied Library Exhibit Includes Geoscience Posters

A first floor Lied Library Exhibit, “Poster Sessions,” provides an introduction to the use and value of poster sessions at academic conferences and meetings. Two examples on display are award winning posters from the recent student-run Geosymposium held on campus. “Gregarious Behavior Recorded in the Tracks of an Early Middle Jurasic Synapsid, Valley of Fire, Clark County, Nevada,” by Jennifer M, Mercante (student) and Stephen M. Rowland (faculty member) and “Petrogenesis of Extracaldera Rhyolites, Yellowstone Volcanic Field, Wyoming,” by Kathleen M. Wooton (student) and Terry Spell (faculty member) .

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Upcoming Seminars

The College of Sciences has established a listserve to better publicize and promote scientific seminars offered throughout the academic year. For more information on upcoming seminars and to subscribe to the listserve, please visit: http://cmse.unlv.edu/seminar/.

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Submit Your News Stories

The College of Sciences E-Newsletter is published on or about the first of each month. Please submit news items via email by the fifteenth of each month, for consideration. You may send your submissions to: Bill Brown, Director of Development william.brown@unlv.edu.

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