Opheodrys aestivus

Number of Pages: 14Integrative BiologyGeological Science

Distal Excurrent Ducts and Penile Morphology of the Urogenital System in the Mississippi Mud Turtle, Kinosternon subrubrum hippocrepis (Chelonia:Kinosternidae)

We examined the distal excurrent ductal morphology and penile anatomy of the urogenital system in the Mississippi Mud Turtle, Kinosternon subrubrum hippocrepis, from a small sample of individuals collected in Arkansas in order to provide additional information regarding turtle urogenital anatomy. Specifically, we focused on the basic anatomy and histology of distal excurrent ducts (ductus deferens and ureter), associated structures (urogenital papillae), and penile histology in this kinosternid turtle. In addition, we provide an overview of the gross urogenital anatomy in this turtle, given that little detailed information exists on this topic in the chelonian literature

The Emerging 'Post-Doha' Agenda and the New Regionalism in the Asia-Pacific

This paper considers emerging commercial policy challenges facing the Asia-Pacific region in light of the impasse reached at the Eighth World Trade Organization (WTO) Ministerial Meeting in December 2011. It underscores that, while marginal liberalization of trade barriers under the Doha Development Agenda may not be forthcoming in the short- or even medium-term, the WTO has been successful in erecting a rules-based system of global governance and continues to be extremely important to the future health of the international trading system. Nevertheless, one can expect the current trend toward bilateral and regional free-trade areas (FTAs) will continue, particularly since it is easier to make progress toward "deep integration" in a smaller group of like-minded countries than in the context of the general WTO membership. This paper considers how the FTA trend is developing in the Asia-Pacific region and what its prospects are in the future. It stresses that regional - as opposed to bilateral - arrangements will be essential to the region for economic (e.g., supporting regional production networks) as well as diplomatic-political goals. This "new regionalism" which has been supported by Asia-Pacific Economic Cooperation (APEC), will lead to significant reductions in the costs associated with bilateral FTAs (e.g., lower costs associated with rules of origin, improved utilization rates) and has many advantages over "noodle-bowl" bilateralism

Quantitative localized proton-promoted dissolution kinetics of calcite using scanning electrochemical microscopy (SECM)

Scanning electrochemical microscopy (SECM) has been used to determine quantitatively the kinetics of proton-promoted dissolution of the calcite (101̅4) cleavage surface (from natural “Iceland Spar”) at the microscopic scale. By working under conditions where the probe size is much less than the characteristic dislocation spacing (as revealed from etching), it has been possible to measure kinetics mainly in regions of the surface which are free from dislocations, for the first time. To clearly reveal the locations of measurements, studies focused on cleaved “mirror” surfaces, where one of the two faces produced by cleavage was etched freely to reveal defects intersecting the surface, while the other (mirror) face was etched locally (and quantitatively) using SECM to generate high proton fluxes with a 25 μm diameter Pt disk ultramicroelectrode (UME) positioned at a defined (known) distance from a crystal surface. The etch pits formed at various etch times were measured using white light interferometry to ascertain pit dimensions. To determine quantitative dissolution kinetics, a moving boundary finite element model was formulated in which experimental time-dependent pit expansion data formed the input for simulations, from which solution and interfacial concentrations of key chemical species, and interfacial fluxes, could then be determined and visualized. This novel analysis allowed the rate constant for proton attack on calcite, and the order of the reaction with respect to the interfacial proton concentration, to be determined unambiguously. The process was found to be first order in terms of interfacial proton concentration with a rate constant k = 6.3 (± 1.3) × 10–4 m s–1. Significantly, this value is similar to previous macroscopic rate measurements of calcite dissolution which averaged over large areas and many dislocation sites, and where such sites provided a continuous source of steps for dissolution. Since the local measurements reported herein are mainly made in regions without dislocations, this study demonstrates that dislocations and steps that arise from such sites are not needed for fast proton-promoted calcite dissolution. Other sites, such as point defects, which are naturally abundant in calcite, are likely to be key reaction sites