111th Congress

This report covers the North American Free Trade Agreement (NAFTA), and U.S.-Mexico drug trafficking. It also looks at migration, environmental issues, legislation in the 111th Congress, and the relationship between the Obama Administration and Mexico

Latin America and the Caribbean: Illicit Drug Trafficking and U.S. Counterdrug Programs

This report provides an overview of the drug flows in the Americas and U.S. antidrug assistance programs in the region. It also raises some policy issues for Congress to consider as it exercises oversight of U.S. antidrug programs and policies in the Western Hemisphere

110th Congress

This report provides an overview of U.S. relations with Latin America and the Caribbean and focuses on the role of Congress and congressional concerns

Latin America and the Caribbean: U.S. Policy and Key Issues for Congress in 2012

This report provides an overview of U.S. policy toward Latin America and the Caribbean, including the Obama Administration's priorities for U.S. policy and a brief comparison of policies under the Obama and Bush Administrations. It then examines congressional interest in Latin America, first providing an overview, and then looking at selected countries and regional issues and identifying key policy issues facing Congress in 2012. The final section of the report analyzes several upcoming events in the region in 2012 that could have an impact on developments in several countries or on U.S. relations with the region

Diminution of Voltage Threshold Plays a Key Role in Determining Recruitment of Oculomotor Nucleus Motoneurons during Postnatal Development

The size principle dictates the orderly recruitment of motoneurons (Mns). This principle assumes that Mns of different sizes have a similar voltage threshold, cell size being the crucial property in determining neuronal recruitment. Thus, smaller neurons have higher membrane resistance and require a lower depolarizing current to reach spike threshold. However, the cell size contribution to recruitment in Mns during postnatal development remains unknown. To investigate this subject, rat oculomotor nucleus Mns were intracellularly labeled and their electrophysiological properties recorded in a brain slice preparation. Mns were divided into 2 age groups: neonatal (1–7 postnatal days, n = 14) and adult (20–30 postnatal days, n = 10). The increase in size of Mns led to a decrease in input resistance with a strong linear relationship in both age groups. A well-fitted inverse correlation was also found between input resistance and rheobase in both age groups. However, input resistance versus rheobase did not correlate when data from neonatal and adult Mns were combined in a single group. This lack of correlation is due to the fact that decrease in input resistance of developing Mns did not lead to an increase in rheobase. Indeed, a diminution in rheobase was found, and it was accompanied by an unexpected decrease in voltage threshold. Additionally, the decrease in rheobase co-varied with decrease in voltage threshold in developing Mns. These data support that the size principle governs the recruitment order in neonatal Mns and is maintained in adult Mns of the oculomotor nucleus; but during postnatal development the crucial property in determining recruitment order in these Mns was not the modifications of cell size-input resistance but of voltage threshold

Characterizing the scent and chemical composition of Panthera leo marking fluid using solid-phase microextraction and multidimensional gas chromatography–mass spectrometry-olfactometry

Lions (Panthera leo) use chemical signaling to indicate health, reproductive status, and territorial ownership. To date, no study has reported on both scent and composition of marking fluid (MF) from P. leo. The objectives of this study were to: 1) develop a novel method for simultaneous chemical and scent identification of lion MF in its totality (urine + MF), 2) identify characteristic odorants responsible for the overall scent of MF as perceived by human panelists, and 3) compare the existing library of known odorous compounds characterized as eliciting behaviors in animals in order to understand potential functionality in lion behavior. Solid-phase microextraction and simultaneous chemical-sensory analyses with multidimensional gas-chromatography-mass spectrometry-olfactometry improved separating, isolating, and identifying mixed (MF, urine) compounds versus solvent-based extraction and chemical analyses. 2,5-Dimethylpyrazine, 4-methylphenol, and 3-methylcyclopentanone were isolated and identified as the compounds responsible for the characteristic odor of lion MF. Twenty-eight volatile organic compounds (VOCs) emitted from MF were identified, adding a new list of compounds previously unidentified in lion urine. New chemicals were identified in nine compound groups: ketones, aldehydes, amines, alcohols, aromatics, sulfur-containing compounds, phenyls, phenols, and volatile fatty acids. Twenty-three VOCs are known semiochemicals that are implicated in attraction, reproduction, and alarm-signaling behaviors in other species

Latin America: Energy Supply, Political Developments, and U.S. Policy Approaches

This report examines Latin America’s current political environment and its apparent effect on energy production in the region. It also discusses efforts to help many Latin American and Caribbean countries dependent on energy imports, including Venezuela’s preferential oil programs, the Mexico-led Meso-American Energy Integration Program, and U.S.-Brazilian cooperation on biofuels. The report also examines policy approaches that have been proposed for increased hemispheric energy cooperation, congressional interest in the topic of hemispheric energy security, and related legislative initiatives

U.S.-Mexican Water Sharing: Background and Recent Developments

This report describes U.S.-Mexican water sharing of the Colorado and Rio Grande rivers pursuant to binational agreements. The International Boundary and Water Commission (IBWC) is charged with addressing issues that arise during application of binational water treaties