Sigma Xi Distinguished Lecturers 2004-2005 Abstracts

Nicholas K. Coch

Are America's Beaches all washed up? (P)
Extensive coastal development, lack of hurricane danger perception, modification of shorelines with engineering structures and a rising sea level have increased the danger to coastal inhabitants and their structures. This talk describes how coastal systems work and evolve naturally as well as how anthropogenic and natural changes are causing problems on our coasts. Major problems will occur as we continue to build fixed structures on a moving shoreline. What are our options?

Hurricane Hazards in the U.S. (P) Hurricanes pose a major problem for the Gulf and Atlantic coastal regions because recent research suggests that in the next decades, hurricane frequency, and possible intensity, will increase. Our coastal areas are more vulnerable to damage because of overbuilding, alterations from engineering structures and rising sea level. This talk describes the basic mechanics of hurricane damage and how these work on different types of shorelines. No major hurricane has hit a major urban coastal population in the last century - we are statistically overdue. It is vital that we develop the effective hurricane management program before the " Big One" hits the United States shoreline.

Hurricane Damage along the (New England, Mid-Atlantic, South Atlantic, Gulf) Coast. (G) The New England, Mid-Atlantic, South Atlantic, Gulf Coasts each have a different hurricane landfall frequency and potential for destruction. Any one of these regions may be chosen for discussion. The lecture will review past history, present state, specific vulnerabilities, and susceptibility to future damage.

Unique Vulnerability of New york City to Hurricane Destruction (G) The unique demographic, oceanographic, topographic, bathymetric, and geographic conditions of the New York-New Jersey Metropolitan region greatly amplify the effects of land falling hurricanes. Based on historical records, past Category 2 hurricanes have done Category 3 damage and Category 3 hurricanes caused damage equivalent to Category 4 hurricanes in the South. This talk deals with how this major urban coastal section will fate in the future. Hurricane landfalls in this area are infrequent, but their consequences can be catastrophic. What will happen when the "Big One" hits the "Big Apple?"

Forensic Hurricanology and the Reconstruction of Historic Hurricanes (S) Forensic Hurricanology utilizes information obtained from recent hurricanes to interpret damage patters in historic hurricanes. The causal mechanisms for given damage patterns is obtained from modern quantitative data. Damage descriptions from a wide variety of historic sources provides descriptions of damage patterns. These are interpreted in light of the recent data. Inferences are made about wind speed, radius of maximum winds, surge levels and translational velocities from the historical data. Areal plotting of the data makes a reconstruction of the wind field possible. Joint analysis of the data with specialists from the National Hurricane Center, make it possible to produce dynamic computer models of the 17th through 19th century hurricanes.

Dynamics of Hurricane Destruction by Wind, Waves, Surge and Inland Flooding - Facts and Fallacies (S) Hurricanes cause damage by wave attack, surge flooding and wind at the shoreline and by wind and inland flooding away from the coast. Recent studies have shown that hurricanes are not just coastal events, but can spread damage hundreds of miles inland if they make a high-angle landfall with the coast. The lecture reviews all of these types of damage and provides new insights into each from recent hurricanes. Damage mitigation measures have had mixed success in past hurricanes. It is time for new ideas and a modern perspective before the inevitable major hurricane hits one of our large urban coastal areas.

Billie Collier

Lyocell - The New "Green" Fiber. (P)
Lyocell fibers are manufactured fibers produced by dissolving cellulose in a relatively new, environmentally compatible solvent creating a lyocell solution. Extruding the solution into a water bath forms the fibers, and then the solvent is recycled. Both the cellulose and the solvent are biodegradable. The lyocell fibers are converted into premium fabrics and are marketed under the trade names Tencel® and Lyocell®. The current commercial cellulose source is a blend of two grades of dissolving pulp from wood that has been significantly treated. Our research is related to producing similar lyocell solutions and fibers from other sources including recycled material and agricultural residues, without the chemical treatment necessary to form dissolving pulp.

Green Processing of Cellulose to Value-Added Products (G)
The traditional process of converting cellulose to rayon has significant environmental problems that have led to most rayon being produced offshore. A relatively new environmentally green process for converting cellulose to a manufactured fiber with improved properties over rayon involves forming a solution of cellulose from dissolving pulp in N-methylmorpholine oxide near monohydrate, i.e. forming a lyocell solution. Extruding the solution into a water bath forms the fibers, and then the solvent is recycled. This is the lyocell process and the fibers produced are converted into premium fabrics and are marketed under the trade names Tencel® and Lyocell®. However the commercial preparation of the starting material, dissolving pulp, usually involves using the Kraft process with harsh chemicals and subsequent additional treatment. Our research is related to producing similar lyocell solutions from other sources including recycled materials and agricultural residues, without the chemical treatment necessary to form dissolving pulp.

Rheology of Lyocell Solutions Lyocell Solutions from Alternative Cellulose Sources (S)
Cellulose dissolved in N-methylmorpholine oxide near monohydrate, forming lyocell solutions, is extruded into water to form lyocell fibers and the solvent is concentrated and recycled. Fibers are produced in this lyocell process and are converted into premium fabrics, marketed under the trade names Tencel® and Lyocell®. However the preparation of dissolving pulp usually involves using the Kraft process with harsh chemicals and additional treatment. Our research is related to producing similar lyocell solutions from other sources including recycled materials and agricultural residues, without the chemical treatment necessary to form dissolving pulp that is the commercial starting material for the lyocell process. We have demonstrated that the shear and elongational rheology of some recycled materials and agricultural residues at appropriate concentrations are similar to those of the two typical grades of dissolving pulp used commercially. These alternate sources do not require the harsh treatment needed to form dissolving pulp and should be effective, lower cost, and environmentally desirable starting materials for lyocell fibers.

John Collier

Lyocell - The New "Green" Fiber. (P)
Lyocell fibers are manufactured fibers produced by dissolving cellulose in a relatively new, environmentally compatible solvent creating a lyocell solution. Extruding the solution into a water bath forms the fibers, and then the solvent is recycled. Both the cellulose and the solvent are biodegradable. The lyocell fibers are converted into premium fabrics and are marketed under the trade names Tencel® and Lyocell®. The current commercial cellulose source is a blend of two grades of dissolving pulp from wood that has been significantly treated. Our research is related to producing similar lyocell solutions and fibers from other sources including recycled material and agricultural residues, without the chemical treatment necessary to form dissolving pulp.

Green Processing of Cellulose to Value-Added Products (G)
The traditional process of converting cellulose to rayon has significant environmental problems that have led to most rayon being produced offshore. A relatively new environmentally green process for converting cellulose to a manufactured fiber with improved properties over rayon involves forming a solution of cellulose from dissolving pulp in N-methylmorpholine oxide near monohydrate, i.e. forming a lyocell solution. Extruding the solution into a water bath forms the fibers, and then the solvent is recycled. This is the lyocell process and the fibers produced are converted into premium fabrics and are marketed under the trade names Tencel® and Lyocell®. However the commercial preparation of the starting material, dissolving pulp, usually involves using the Kraft process with harsh chemicals and subsequent additional treatment. Our research is related to producing similar lyocell solutions from other sources including recycled materials and agricultural residues, without the chemical treatment necessary to form dissolving pulp.

Rheology of Lyocell Solutions Lyocell Solutions from Alternative Cellulose Sources (S)
Cellulose dissolved in N-methylmorpholine oxide near monohydrate, forming lyocell solutions, is extruded into water to form lyocell fibers and the solvent is concentrated and recycled. Fibers are produced in this lyocell process and are converted into premium fabrics, marketed under the trade names Tencel® and Lyocell®. However the preparation of dissolving pulp usually involves using the Kraft process with harsh chemicals and additional treatment. Our research is related to producing similar lyocell solutions from other sources including recycled materials and agricultural residues, without the chemical treatment necessary to form dissolving pulp that is the commercial starting material for the lyocell process. We have demonstrated that the shear and elongational rheology of some recycled materials and agricultural residues at appropriate concentrations are similar to those of the two typical grades of dissolving pulp used commercially. These alternate sources do not require the harsh treatment needed to form dissolving pulp and should be effective, lower cost, and environmentally desirable starting materials for lyocell fibers.

Carving Crazy Horse: Art and Engineering of Blasting Massive Rock Monuments (P, G, S)
When completed, Crazy Horse Memorial, an equestrian figure being carved in the round, will be the largest mountain carving in the world. Millions of tons of rock have been removed to date. The project began in 1939 when Chief Henry Standing Bear wrote to Korczak Ziolkowski asking him to carve the 600 ft. high monument in the Black Hills of South Dakota. When Korczak died in 1982, his wife Ruth and their children made the commitment to carry on his Dream, and work on the mountain continues today. This lecture describes the process of creating the monument. Project management includes financing, scheduling and public relations. Artistic considerations include replication of the prototype, sequencing of operations and final details. Blast matters involve drilling, explosive loading and initiation sequence. Rock mechanics aspects include special equipment, reinforcement, final smoothing by heating, and monitoring vibration response. The presentation includes color slides and movies and can be tailored to suit the interests of the audience. More information about the project can be found at www.crazyhorse.org.

Watching Our Infrastructure: Autonomous Surveillance of Critical Facilities and the Internet (G, S)
Internet display and digital data acquisition have revolutionized the process of monitoring the condition of critical facilities. Development of low power consumption microprocessors and storage devices now allow on site data acquisition without human intervention. Land-line modems, cell phones, and satellite communication provide the means of transmitting data from any location on the planet. Finally, internet display allows acquired information to be reviewed from any location. The Northwestern Infrastructure Technology Institute has been installing systems involving all three components to monitor bridges and other critical facilities. This lecture will describe details of these installations, as well as data acquired, its internet display and interpretation. Examples of ITI installations and activity can be found at www.iti.northwestern.edu/acm or www.iti.northwestern.edu/tdr by pressing "operational sites" on the left side bar.

Douglas J. Durian

The Physics of Foams (G)
Foams consist of gas bubbles jammed tightly together in a small amount of liquid. As a form of matter, are they solid, liquid, or gas? In fact foams possess hallmark features of all three basic states, in ways that are just now being understood. This talk will give an overview of the fascinating behavior of foams and a glimpse into current research topics considered by physicists and mathematicians.

Turning up the Heat on Effective Temperatures (S)
If left alone, materials like foam and sand are jammed -- the bubbles and grains are tightly locked into some static packing configuration and the material acts like a solid. If subjected to large forces, the packing units can unjam and the material acts like a liquid. Unlike a real liquid, though, the random grain dynamics are not controlled by thermal energy. What sort of statistics should the microscopic motions possess? In principle statistical mechanics does not apply. Surprisingly, in certain cases, it appears to hold but with a well-defined "effective temperature" that is much greater than the thermal temperature.

The Glamorous World of the Forensic Anthropologist: The True Story (P)
Television shows such as the New Detectives, Medical Detectives, CSI and even the X-Files have introduced many people to the work of forensic anthropologists. Consequently practicing professionals spend considerable time fielding questions from those who wish to make it their career. This presentation discusses a) what we do when not on television, b) what are the legal and health risks involved, and c) are there jobs in this field.

Forensic Analysis of Skeletal Trauma (G)
Bone has biomechanical properties that allow it to resist compressive and tensile forces, although to differing extents. Fracture is produced when the strength of the bone is surpassed. How the bone breaks allows forensic anthropologists to track back to the forces that produced the breaks and match them with known injury characteristics. Focusing on blunt force trauma and gunshot injuries, this presentation discusses the possibilities and limitations of skeletal analysis within the forensic context. Photographs of bone injuries and some soft tissue trauma are included.

The Legal Responsibilities of Forensic Anthropologists (S)
The skills of the skeletal biologist are the foundation upon which forensic anthropologists have built careers. How does forensic anthropology analysis differ from conducted in other contexts? What should anyone know before agreeing to take on a forensic case? What are the risks and responsibilities and how are the limitations of the field handled? May include images of decomposing bodies and soft tissue trauma.

Charles Fenimore

Picture Perfect: Motion imaging and human vision in the age of electronics (P, G)
At the intersection of electronic imaging and modern computing lies digital cinema. Movies without film are made possible by the emergence of novel electronic image presentation devices. But digital cinema is merely one example of a dramatic transformation in the production, storage, communication, and presentation of imagery. Microelectronic technology is dramatically extending the capabilities of cameras and film scanners, the basic tools for capturing pictures; it has made it possible for a desk top computer to perform the functions of an entire production studio; and it is improving the compression which is critical to communicating and preserving imagery. Its impact is felt in the ways information is conveyed in medicine, education, and entertainment.

Writing of a Cézanne still life, D. H. Lawrence notes its "physical, and even sensual qualities". This "physical quality" is akin to the modern imager's "sense of presence". The artist attempts to create that quality using available tools and technology. The engineer attempts to improve the capabilities of the technology, but confronts a fundamental challenge: the sampling of a regular array of pixel values to produce an image imposes limits on the level of detail that can be captured faithfully. Exceed the limits and one sees Moiré patterns, or other artifacts, in place of the image. Some indications of how far present-day imaging systems are from being able to present the full range of visual experience are:

• A sun-lit lake may have sparkles a million times brighter than the detail seen in shadows; yet for the best projector the brightest white is only about a thousand times brighter than the darkest black.
• The eye can see billions of colors, yet most displays present only millions, with limited range.
• Typical viewing of a high-definition display fills a small portion of a human's field of vision. And most video pictures are flashed at between 24 and 30 times per second, although humans are sensitive to distracting flicker even at rates exceeding 60 flashes per second.

With today's technology, the users of imagery are presented with new viewing experiences. The eye is stimulated in previously unknown ways and these new visual experiences challenge the understanding of human vision. The new imaging modalities transform the ways in which we receive information and entertainment and open horizons in the study of human vision. They require new conceptions of pictures and picture quality.

Measuring picture quality in high resolution, high dynamic range imagery (S)
Producing and showing high quality moving pictures without film is made possible by the emergence of novel electronic systems that work with extended pixel counts and color palettes. While the sampling theorem specifies the maximum resolution of a digital signal processing system, it does not tell the whole story on picture quality. Generally, the evaluation of picture quality is related to the response of a human viewer. For this reason, the evaluation of image processing systems, such as the recently improved MPEG compression, includes both subjective and computed (or model-based) evaluation. Contrast is the essential element in understanding changing picture quality. Its role is illustrated by examples from recent compression assessments and from preservation studies showing the tradeoffs between resolution and dynamic range.

Computing Metaphors and "E-Culture" (G)
Computational metaphors -- computer systems whose functionality intentionally mimics familiar human objects and entities -- are the foundation for many powerful computer systems. We are exploring some examples of this idea in the sciences and engineering areas. In particular, we are we are investigating different computer interfaces, whereby we look into the issue of creating information systems that reflect and support specific cultures. In this talk, I will highlight some of the issues raised by the work of the new Institute for African-American ECulture (http://www.iaaec.org).

Grid Power to the People (G)
Access to high quality distributed computing, information, and experimental resources are transforming science and the scientific community. This talk reviews the impact of distributed computing on selected scientific disciplines and projects and points to some key issues for future development.

Micromagnetic Simulations: Dynamics and Topology (S)
We review large-scale computer simulation of the Landau-Lifshitz equations which model the dynamics of magnetic materials in 3D. Of special interest is the representation of topological features of the model in discrete computer simulations.

Judith Herzfeld

The Subversiveness of Asking "Why?": Social Implications of Neuro-determinism (P)
It is common to wonder why people behave as they do. Less common is consideration of the implications of even supposing that the question might be answerable. This seminar considers causal accounts of human actions, and consequences for notions of responsibility and punishment. We find that while some traditional ideas are undermined, others are clarified and provide sufficient leeway for individual motivation and communal defense.

Crowding Induced Order: From Liquid Crystals to Cell Biology (G)
Solution non-ideality is more commonly regarded as an unpleasant fact of life than as a source of interesting phenomenology. Usually represented by simple activity coefficients overlaid on ideal descriptions, non-ideality is generally seen as quantitatively important but qualitatively insignificant. This seminar will take the opposite point of view, focusing on novel structural features and physical properties that arise from simple steric interactions between solutes in systems ranging from simple binary solutions to complex biological solutions. In the latter, the bundling of cytoskeletal proteins is shown to be driven simply by their excluded volume and the roles of cross-linking and capping proteins are necessarily reassessed.

Sensors and Pumps: Molecular Mechanisms of Retinal-Based Signal and Energy Transducers (G)
Halophilic archae produce retinal-containing membrane proteins similar to the mammalian visual pigments. These rhodopsins include energy transducers that use light to drive ion transport, as well as signal transducers that use light to stimulate phototaxis. The rhodopsins are thus light-driven analogues of the chemically-driven energy transducers (e.g., membrane ATPases) and signal transducers (e.g., hormone receptors) found in mammalian cells. In this talk we will consider how the requirements for effective sensors and pumps differ and how retinal is well suited to serve as a chromophore in both types of systems.

Pumping Ions: NMR Studies of Solar Energy Transduction in the Bacteriorhodopsin Photocycle (S)
Bacteriorhodopsin is a relatively stable membrane protein that functions as a light-driven ion pump. Interest has focused on the "gating" mechanism whereby ion release and uptake occur on opposite sides of the active site in the L-to-M and M-to-N transitions of the bacteriorhodopsin photocycle. Solid-state NMR spectra of the L, M and N photocycle intermediates have been obtained by trapping at low temperatures. Features of the spectra of these intermediates indicate that (1) "gating" is associated with the release of torsion in the chromophore and (2) the pump may be pumping hydroxyl ions into the cell rather than protons out of the cell.

Zhibing Hu

Hydrogel Opals (G, S)
Our group has recently developed a new class of nanostructured hydrogels. The central idea to first synthesize monodispersed hydrogel nanoparticles, then self-assemble them into a 3D network, and eventually covalently bond them. The covalent bonding contributes to the structural stability, while self-assembly provides crystal structures that diffract light, resulting in a striking iridescence like opal. The work reviewed in this talk will include synthesizing mono-dispersed N-isopropylacrylamide nanoparticles with functional groups attached, characterizing self-assembling processes, describing the crosslinking chemistry, modeling elastic and optical properties associated with the nano-structures, and applying such nano-structured hydrogels for controlled drug release. The new material allows us to obtain useful functionalities not only from the constituent building blocks, such as their abilities to simulate biological tissues and to swell or collapse reversibly in response to external stimuli, but also from the long-range ordering that characterizes these structures.

Smart Hydrogels (P)
Hydrogels are a unique class of macromolecular networks and are particularly useful in biomedical and pharmaceutical applications mainly due to their high water content, which is similar to natural tissue, as well as their bio-compatibility. This talk will review some recent progresses on the smart hydrogels that may be induced to swell or shrink (taking up or expelling water between the crosslinked polymer chains) in response to a variety of environmental stimuli. These stimuli include changes in pH or temperature, or the presence of a specific chemical substance. A host of researchers are now rushing to explore the applications of these smart materials, aiming for everything from biosensors to drug release devices. And since gels can exert a force when they swell, they even have potential as actuators or artificial muscles for robots or prostheses. Hydrogels get smatter as their structures are engineered by incorporating several different gels. For example, a shape memory gel that consists of a responsive polymer network and a non-responsive network can change its shapes at various temperatures. Furthermore, a nanostructured hydrogel will be described, which displays a striking iridescence like precious opal but is soft and flexible like Jell-O.

Ted Labuza

Bioterrorism and the Food Chain: What should we be doing.(P)
Since 9-11 the food industry has been made aware of the potential vulnerabilities in the food distribution system. This talk will review the basic distribution system, what potential toxins or biologic agents could be used and what are the most vulnerable points. The use of security measures will be reviewed. The use of an early warning system will be emphasized as a means for early detection so as to contain the threat.

The History of Military Feeding (P)
Military feed begins thousands of centuries ago with bands of armies following river paths. With no systems available 80% of the soldiers assigned to scavange for food. Not until the civil War did the US begin to think of prepared rations. This talk will trace some of the changes that took place since then including the famous K ration and the MREs of Vietnam and Kuwait. These principals were also put to use in designing the space food feeding systems in place today.

Before Equilibria Diagrams: Application of glass transition (DSC) and Xray diffraction to evaluate structural changes of food systems in storage (cotton candy, soft cookies and sugar snap cookies) (G)
In 1948 Schmidt and Marles stated the glass transition was important in confectionery foods like hard candy (Principles of High Polymer Theory and Practice, McGraw Hill.) This message was lost on the food industry until 1988 when Franks, Slade and Levine revived the glass transition phenomena and started a revolutionary change in understanding water relations in food especially with respect to texture. This presentation will review work that our group has been involved in related to moisture physical state changes and glass transition phenomena in confectionery and cereal based products.

The Crystallization of Sugars in Foods, Drugs and Biologics (S)
Most processing steps (drying, baking, extrusion) that involve water removal from a food system results in the formation of a glassy state for any of the sugars present. During storage as moisture is gained or temperature abuse occurs, these sugars begin to crystallized leading to caking of powders, collapse of cotton candy and the hardening of soft cookies. This process is controlled in part by the glass transition state diagram for the sugar. This talk will discuss the influence of water content on crystallization and show examples of using both Arrhenius kinetics and Williams Landau Ferry kinetics to visualize the combined effect of temperature and rrelative humidity.

The Physics and Chemistry of Water in Foods (G)
Most reactions that occur in limited moisture biological systems (seeds, drugs, biologics and foods) need a liquid phase based on water to occur in. This phase is involved in the dissolution, and mobility of the reactants and products as well as can act a participant in the The binding of water as measured by various means and is represented by it's activity (aw) at some equilibrium condition. The activity of water has an unusual influence on rates of reactions and the stability of macromolecules, with the rate increasing as the degree of binding increases (falling water activity) , reaches a maximum, and then falls to very low values at low water activity (aw). This binding involves vapor - surface binding site interactions (BET or GAB sorption principles), capillary condensation (Kelvin equation ), colligative effects (Raoult's Law) and enthalpic-entropic hydrogen binding which affects dissolution and three dimensional structural stability. The amount of solvent water also affects the free volume - temperature relation of the surrounding polymer matrix, showing the classical glass transition point with significant reductions in phase viscoelastic behavior above the Tg - solvent mass line. This talk will review water binding principles as related to both physical and biological systems and will end with how some of these principles can be applied to stabilize foods at non-thermodynamic equilibrium conditions.

Sea Level Rise and Ancient Maya Civilization (P, G )
What impact did environmental change have in the Classic Maya collapse around A.D. 900 in the tropical lowlands of Guatemala and Belize? Drought, increased rainfall, earthquake, and soil erosion have been suggested as agents in the collapse. Cataclysmic events such as the Ilopango volcanic eruption in the 5th century and Hurricane Iris in the 21st century destroyed Maya communities at other times. However, the impact of environmental change was neither uniformly felt across the Maya lowlands nor necessarily in sync with cultural changes at the end of the Classic. A model of the complex interplay between environmental change (sea-level rise) and cultural change in the Port Honduras of southern Belize is presented. Ongoing fieldwork documents a meter rise in sea level in the area that has inundated Classic Maya sites. The presentation will show the discovery and excavation of inundated sites and the evidence supporting late Holocene sea-level rise and the relationship between sea-level rise and archaeological sites in the region. Some, like the salt works in the Punta Ycacos Lagoon, were submerged and hidden from modern view. Others were inundated and are now buried under mangrove peat and living mangroves. Some, like Wild Cane Cay, continued to be occupied by the Postclassic Maya, possible in part due to the accumulation of centuries of ancient Maya trash. I evaluate the factors that led to the abandonment and continued occupation of Maya sites under the stress of sea-level rise. I argue that the abandonment of coastal salt works resulted not from their inundation by sea-level rise but from the lack of inland consumers.

Salt: White Gold of the Ancient Maya (G, P)
Salt, basic to daily human life, was scarce in the tropical rainforests of Belize and Guatemala where the Classic Maya civilization developed between A.D. 300 and 900. The prevailing interpretation is that vast quantities of salt were transported in boats from the salt flats along the north coast of Mexico's Yucatan peninsula. The discovery and excavation of shallow underwater salt works in Punta Ycacos Lagoon, in the Port Honduras of southern Belize, demonstrate there was a closer source of salt for the Classic Maya. Salt cakes were produced by boiling brine in pots over fires at the Punta Ycacos salt works. The standardized manufacture of the pots and other measures indicate specialized production of salt in workshops. The specialized production and the location of the workshops away from domestic settings and any major Maya city indicates the Maya engaged in independent craft production that was not under the direct control of the urban Maya. I will discuss the discovery, excavation, and analysis of the ancient salt works and their implications for our understanding of the ancient Maya economy and politics. Some mention will also be made of sea-level rise, which has inundated the salt works. They were on dry land at the time of their Late Classic use. This presentation can be geared to a general or public audience.

Ancient Maya Sea Traders (S)
Since Christopher Columbus' alleged encounter with a Maya trading canoe off the north coast of Honduras during his fourth voyage to the New World, scholars have debated the antiquity and importance of sea trade in the rise and fall of ancient Maya civilization. This presentation will summarize my studies of Maya sea trade, focusing on the analysis of obsidian-a volcanic glass not naturally occurring in the limestone platform of Mexico's Yucatan peninsula, Belize, and Guatemala where the Classic Maya civilization developed between A.D. 300 and 900. Quantities of obsidian were imported to make sharp cutting tools for a variety of tasks, including ritual bloodletting. The ability to chemically fingerprint the source locations of the obsidian trade goods assists in the reconstruction of ancient transportation and trade routes. I present the results of my fieldwork, including the excavation of sites in the search for obsidian and other trade goods at the Maya trading ports of Moho Cay and Wild Cane Cay in Belize, as well as regional survey in the Port Honduras of southern Belize. A variety of analyses on obsidian from these sites are presented to argue that Maya sea trade had a long and significant importance in the development of Maya civilization and in the subsequent Postclassic period. The analyses include chemical and visual identification of the sources of obsidian artifacts (XRF and NAA) as well as measures of the conservation of the raw material in the manufacture of blades (CE/M or "cutting edge to mass" index) and the relative abundance of obsidian artifacts (obsidian densities).

Robert Shepard

In Search of the Influential Scientist. (P,G)
Demographic factors have come into play in the nation's elementary and middle school grade levels. This means that America's classrooms reflect a broad spectrum of diverse backgrounds and ethnic make up. If the sine qua non of a modern economy is a well-educated, versatile workforce able to conduct R&D and to convert its results into innovative products, processes, and services, how can the U.S. produce more globally competitive scientists and engineers in the future from a talent pool that has been historically underutilized in the past? This talk discusses an option for expanding the potential talent pool from among home-grown resources.

Historically Black Colleges and Universities (HBCUs): Myths and Misunderstandings. (P,G)
Historically black colleges and universities (HBCUs) are institutions established prior to 1964, whose principal mission was, and is, the education of African Americans. The HBCUs were founded and developed in an environment unlike that of any other institutions of higher education - one of legal segregation. In the midst of such conditions, they strived to serve a population which lived under legal, social, economic, and political restrictions. These early conditions gave rise to myths and misunderstandings that seem to transcend time. This talk strikes a balance between the real and the imaginary.

Paul Sherman

Darwinian Medicine: A New Approach to Health and Disease (P)
The exciting, new interdisciplinary field of Darwinian Medicine takes an evolutionary approach to human health and disease. Whereas medical researchers traditionally study how annoying symptoms are brought about (their underlying mechanisms) and attempt to develop more effective ways to eliminate them, the Darwinian approach emphasizes asking why those symptoms occur in the first place and whether or not it is advisable to eliminate them. These two perspectives are not mutually exclusive: complete understanding of any biological phenomenon requires both mechanistic and functional analyses.

This lecture will illustrate the applicability of Darwinism to medicine, first in determining which symptoms and behaviors serve useful purposes (adaptations) and which do not (pathologies), and second in considering how to treat such symptoms as fever, anemia, pain, allergies, cravings for fat, menstruation, morning sickness, and emerging infectious diseases. Decisions about whether or not to eliminate particular symptoms will be better informed if they include consideration of whether those symptoms are aiding or hindering an individual's recovery. Thus, a Darwinian approach may complement and enhance traditional medical practices in the 21st century.

Why We Use Spices (G)
For centuries spices have been important in food preparation throughout the world. However, patterns of spice use differ considerably among cultures. This lecture will introduce the new field of Darwinian gastronomy, and address two specific questions, namely (1) what factors underlie cultural differences in spice use?, and (2) why are spices used at all? To investigate these issues, I quantified the frequency of use of all spices (n=43) in the meat-based recipes (4,578) of all countries (36) for which traditional cookbooks (93) could be located. I also compiled information on climatic variables, ranges of spice plants, and their antimicrobial properties. These data were used to investigate several alternative hypotheses, including that spices disguise the taste and smell of spoiled foods, increase perspiration and evaporative cooling, provide micronutrients, or eliminate foodborne microorganisms.

In support of the latter hypothesis, secondary compounds in all spice plants inhibit or kill foodborne bacteria, some very effectively. Within and among countries, proportions of recipes containing spices, numbers of spices per recipe, total spices used, and use of the most potent antibacterial spices all increase with increasing mean annual temperatures (an indicator of relative spoilage rates of unrefrigerated foods).

A corollary of the antimicrobial hypothesis is that, within cuisines, vegetable dishes should be less spicy than meat dishes, because cells of dead plants are better protected physically and chemically against bacterial and fungal invasions than cells of dead animals, whose immune system ceased functioning at death. As predicted, among countries, vegetable dishes called for fewer spices/recipe than meat dishes, and 38 of 41 individual spices were used less frequently in vegetable recipes. Proportions of recipes calling for >1 spice, and >1 extremely potent antimicrobial spice also are lower for vegetable than meat dishes in most countries.

Although the proximate (immediate cause) reason spices are used obviously is to enhance food palatability, the ultimate (long-term) reason most likely is to cleanse foods of bacteria and fungi. Prior to widespread availability of refrigeration and artificial food preservation, spices probably enhanced the health, longevity, and reproductive success of people who found their flavors enjoyable. This, in turn, explains why spices taste good to their descendants.

Protecting Ourselves from Food. (S)
Most of us will eat more than 75,000 meals in our lifetimes. And, for many, eating is the most dangerous thing we do, because ingesting bits and pieces of the outside world provides a free pass to the bloodstream for whatever lurks in the foodstuffs. Foodborne pathogens, especially in "leftovers," have been problematic ever since early hominids began killing game that was too large to consume immediately. This lecture will take a Darwinian approach and discuss two mechanisms, one cultural and one physiological, that serve to protect us from what we eat.

The cultural mechanism involves cooking with spices. Usually spices are considered solely as flavorings, but they also have antimicrobial properties deriving from secondary compounds that evolved in the plants as protection against their own biotic enemies. Humans use these natural pharmaceuticals to help cleanse food of pathogens and retard food spoilage. Spice use is more prominent in traditional cuisines from hot than cool climates, and more prominent in meat than vegetable dishes (the former are more conducive to bacterial growth). Prior to widespread refrigeration and artificial food preservation, spice use probably enhanced the health, longevity, and reproductive success of people who found their flavors enjoyable.

However, the very chemicals that inhibit foodborne pathogens can have negative side-effects as carcinogens, teratogens, and abortifacients. These dangers are particularly relevant for pregnant women. How can they protect themselves and their delicate embryos from the dangers of foodborne illnesses, on the one hand, and from naturally-occurring plant toxins on the other? The answer is the intricate physiological mechanism known as "morning sickness."

Food aversions during the first trimester (when embryogenesis is most sensitive to disruption), reinforced by nausea and vomiting, focus primarily on meats and strong-tasting vegetables (i.e., the most "dangerous" foodstuffs in our evolutionary past). Miscarriages and fetal deaths are less likely to occur to women who experience morning sickness than those who do not, and the greater the symptoms the better the pregnancy outcome. Traditional societies with no evidence of morning sickness rarely eat meat or strong-tasting plants, instead consuming mainly corn. Morning "sickness" apparently is a misnomer - rather it is a prophylactic mechanism the provides wellness insurance.