Lead Exposure of Obligate Avian Scavengers in Eastern North America

Lead is a toxic element within the body of living organisms. Lead poisoning cases still occur in both humans and wildlife on a regular basis in the United States. Although the harmful effects of lead within the body are well known, such as decreased IQ in children, increased renal dysfunction, hypertension, anemia, and other morbid and mortal consequences in humans and wildlife, lead continues to be used in anthropogenic activities today. Through the use of lead in ammunition and fishing sinkers, and its presence in coal-fired power plant and other industrial emissions, lead is dispersed throughout modern human and natural systems. Due to the persistence of anthropogenic lead-use, it is necessary to understand the pervasiveness of this toxin in both modern ecosystems and throughout the body of individuals.;To understand the degree to which wildlife populations are chronically exposed, we quantified lead levels within American black vultures ( Coragyps atratus) and turkey vultures (Cathartes aura); two species that are useful as environmental sentinels in eastern North America. Individuals of both vulture species are known to be more resistant to the effects of lead toxicity than are many other animals. This resistance allows vultures to accumulate and harbor lead for a longer period of time than more sensitive species, thus providing us with a lifetime lead exposure history. In our study, chronic lead exposure was quantified from femur lead concentrations of 98 black vultures and 10 turkey vultures and compared to lead concentrations of liver tissues sampled from the same individuals. We found that the extent to which vultures are exposed suggests that anthropogenic lead permeates eastern North American ecosystems to a previously unrecognized degree. Discovery of an epidemic of chronic lead exposure in such widespread and common species and the failure of soft-tissue sampling to diagnose this pattern has dramatic implications for understanding modern wildlife and human health concerns.;Bone sampling, however, is difficult to replicate in living individuals. Although bone provides information regarding the depth and breadth of lead exposure, blood is most commonly sampled in live individuals. This is because phlebotomy is one of the most minimally invasive sampling techniques currently available, which makes it attractive despite the fact that blood and other soft tissues (liver, kidney) are indicative of only recent exposure to lead. However, if an individual\u27s blood (collected by phlebotomy) or muscle (collected by biopsy) lead levels could be statistically linked to the amount of lead found within its bone, it would permit use of less invasive sampling techniques to reveal total body lead burden. Therefore, to determine if soft tissue lead concentrations have a quantifiable relationship with femur lead concentrations, we collected and analyzed multiple tissues (femur, liver, kidney, breast muscle, and thigh muscle) from the 108 black and turkey vultures mentioned above. We found that although all soft tissues were poor predictors of bone lead levels, kidney lead concentrations best predicted femur lead concentrations. These poor relationships, however, between soft tissues and bone suggest that the sampling of tissues other than bone is unlikely to provide substantial insight into the long-term lead burden that birds face

Augmented Reality Chemistry: Transforming 2-D Molecular Representations into Interactive 3-D Structures

Spatial reasoning is defined as the ability to generate, retain, and manipulate abstract visual images. In chemistry, spatial reasoning skills are typically taught using 2-D paper-based models, 3-D handheld models, and computerized models. These models are designed to aid student learning by integrating information from the macroscopic, microscopic, and symbolic domains of chemistry. Research has shown that increased spatial reasoning abilities translate directly to improved content knowledge. The recent explosion in the popularity of smartphones and the development of augmented reality apps for them provide, a yet to be explored, way of teaching spatial reasoning skills to chemistry students. Augmented reality apps can use the camera on a smartphone to turn 2-D paper-based molecular models into 3-D models the user can manipulate. This paper will discuss the development, implementation, and assessment of an augmented reality app that transforms 2-D molecular representations into interactive 3-D structures

Augmented Reality Chemistry: Transforming 2D Molecular Representations into Interactive 3D Structures

Spatial reasoning is defined as the ability to generate, retain, and manipulate abstract visual images. In chemistry, spatial reasoning skills are typically taught using 2-D paper-based models, 3-D handheld models, and computerized models. Research has shown that increased spatial reasoning abilities translate directly to improved content knowledge. The recent explosion in the popularity of smartphones and the development of augmented reality apps for them provide, a yet to be explored, way of teaching spatial reasoning skills to chemistry students. Augmented reality apps utilize the camera on a smartphone to turn 2D paper-based molecular models into 3D models the user can manipulate. This presentation will discuss our development of an augmented reality app that transforms 2D molecular representations into interactive 3D structures. Attendees will participate in a series of interactive activities to demonstrate the use of the app in the collegiate chemistry classroom

Harmonic Generation from Relativistic Plasma Surfaces in Ultra-Steep Plasma Density Gradients

Harmonic generation in the limit of ultra-steep density gradients is studied experimentally. Observations demonstrate that while the efficient generation of high order harmonics from relativistic surfaces requires steep plasma density scale-lengths ($L_p/\lambda < 1$) the absolute efficiency of the harmonics declines for the steepest plasma density scale-length $L_p \to 0$, thus demonstrating that near-steplike density gradients can be achieved for interactions using high-contrast high-intensity laser pulses. Absolute photon yields are obtained using a calibrated detection system. The efficiency of harmonics reflected from the laser driven plasma surface via the Relativistic Oscillating Mirror (ROM) was estimated to be in the range of 10^{-4} - 10^{-6} of the laser pulse energy for photon energies ranging from 20-40 eV, with the best results being obtained for an intermediate density scale-length

Electronic system design for the WPI formula SAE racecar

This project is the electrical engineering portion of the formula-style racecar design team's project, organized nationally by the Society of Automotive Engineers. It describes all of the electrical components of the racecar, including basis electronics, as well as the advanced design aspects. These advanced designs were clutch-free shifting and a traction control system. Both systems use the same microcontroller circuitry with various sensors, all described in detail, with alternate options discussed. The racecar with all of its components was built and tested for competition in Michigan

Chronic lead exposure is epidemic in obligate scavenger populations in eastern North America

Lead is a prominent and highly toxic contaminant with important impacts to wildlife. To understand the degree to which wildlife populations are chronically exposed, we quantified lead levels within American black vultures (Coragyps atratus; BLVU) and turkey vultures (Cathartes aura; TUVU), two species that are useful as environmental sentinels in eastern North America. Every individual sampled (n = 108) had bone lead levels indicative of chronic exposure to anthropogenic lead (BLVU: x = 36.99 ± 55.21 mg Pb/kg tissue (± SD); TUVU: x = 23.02 ± 18.77 mg/kg). Only a few showed evidence of recent lead exposure (BLVU liver: x = 0.78 ± 0.93 mg/kg; TUVU liver: x = 0.55 ± 0.34 mg/kg). Isotopic ratios suggested multiple potential sources of lead including ammunition, gasoline, coal-fired power plants, and zinc smelting. Black and turkey vultures range across eastern North America, from Quebec to Florida and individuals may traverse thousands of kilometers annually. The extent to which vultures are exposed suggests that anthropogenic lead permeates eastern North American ecosystems to a previously unrecognized degree. Discovery of an epidemic of chronic lead exposure in such widespread and common species and the failure of soft-tissue sampling to diagnose this pattern has dramatic implications for understanding modern wildlife and human health concerns