Spring 2014 Science Seminars

February 6    

Gang Risk Factors, Gang Membership and Academic Readiness

The current study examines middle-school-aged gang and non-gang members and informs educators, parents, and students about the risk factors of gang membership and its effect on academic achievement.  This research uses the same dataset analyzed in the Martinez, Tost, Hilgert, and Woodard-Meyers (2013) study.  Whereas, Martinez, et al, (2013) focused on risk factors related to gang membership, the current study emphasizes risk factors and gang membership as related to student academic readiness.  Results support the need for more gang surveys of the general adolescent population to clarify the extent of gang association among different racial and ethnic groups and its relationship with academic performance.  As a result of the current findings, families and community, along with teachers and school administrators are encouraged to actively engage in a strategic and systematic assessment of the risk factors associated with academic readiness which in turn can be used to facilitate program development for successful academic transition of middle school grades and on to high school.

March 13

How the method for numerical solution of polynomial equations in China evolved from the early methods of square and cube root extraction.

In the 13^th century mathematicians in China reached an unparalleled level of sophistication when they developed a method to solve any polynomial equation of degree three and higher. The method could handle positive, negative, integer and decimal numbers and the accuracy could be pushed to any required level. These techniques were entirely indigenous to China and the origin is in the mathematics created since the 6^th century BC. The most famous of these is the “Jiuzhang suanshu” or loosely translated as “Nine Chapters on the Mathematical Arts” in which the method for square and cube roots are stated. Over 1100 years Chinese algebraists grew to the point that they were able, around 1250 AD to solve any polynomial equation. We will follow the road that leads from one (Nine Chapters) to the complete solution.

April 10

Challenges to recovery of declining amphibian populations

Globally, amphibian populations are declining at a disturbing rate and are experiencing more severe losses than any other taxonomic group that has been studied thus far. I explore key obstacles to successful recovery of declining amphibian populations and identify strategies that could help overcome these obstacles. First, studies that focus on single stressor effects (e.g., UV-B, emerging diseases, climate change) are still vastly popular even though synergisms among multiple factors are now widely recognized to be the drivers of population declines. The former focus has consumed the valuable and limited commodities of time and funding and, ultimately, may have served as a distraction from a more basic issue; i.e., that habitat loss and degradation are the principle drivers of all biodiversity loss. The rates at which populations are declining are rapidly escalating. There is an urgent need to prioritize conservation efforts due to looming fiscal and logistical constraints that management agencies face. Second, monitoring is a key component of conservation and management programs as it is essential to evaluate the trends and dynamics of populations, as well as the effectiveness of management actions. Yet, long-term studies have largely been unavailable for most species of amphibians. A review of the primary literature for the southeastern U.S. revealed geographic, taxonomic and ecological disparities in efforts to monitor amphibian populations in this region. Third, the U.S. Endangered Species Act affords imperiled species a diversity of benefits, yet there can be lengthy delays in the listing process. Moreover, long time lags often exist between the time a species is listed, the time at which a recovery plan is developed and then implemented, and the timing of critical habitat designation. The consequences of delayed protection are potentially severe, allowing population declines to continue, hindering recovery efforts, and possibly contributing to species extinction events. Last, as with many taxa, amphibians often lack sufficient population-level data such as reproductive or survival rates, dispersal, and spatial dynamics, as well as basic natural and life history information. Moving forward with recovery efforts for imperiled amphibians depends upon our ability to overcome these distractions and challenges. Awareness of these data needs will hopefully guide establishment of research and monitoring priorities using an informed decision-making process, particularly with respect to species, habitats and locations that have been largely overlooked in past and ongoing studies.

April 17

Evolution and biogeography of New World venomous snakes

There are approximately 600 species of snakes, in four families, that are considered dangerously venomous; these are found both in the New and Old Worlds. Two adaptive radiations have occurred in the New World giving rise to two major radiations, of approximately 220 describes species of venomous pitvipers and coralsnakes. Understanding the evolution and biogeography of these two groups is important for venom-related research, to elucidate shared biogeographic trends, and to accomplish a stable evolutionarily-valid taxonomy. Using molecular and morphological data I will present evolutionary hypotheses for the relationships among these two groups and utilizing relaxed clock methodologies plus geological data I will discuss what processes have helped shaped the evolution and biogeography of these two venomous groups. We also determine that while pitviper taxonomy is largely congruent with phylogeny, there appear to be a number of cases in coralsnakes in which the taxonomy and phylogeny disagree.