Recovery of Wolverines in the Western United States: Recent Extirpation and Recolonization or Range Retraction and Expansion?

Wolverines were greatly reduced in number and possibly extirpated from the contiguous United States (U.S.) by the early 1900s. Wolverines currently occupy much of their historical range in Washington, Idaho, Montana, and Wyoming, but are absent from Utah and only single individuals are known to occur in California and Colorado. In response, the translocation of wolverines to California and Colorado is being considered. If wolverines are to be reintroduced, managers must identify appropriate source populations based on the genetic affinities of historical and modern wolverine populations. We amplified the mitochondrial control region of 13 museum specimens dating from the late 1800s to early 1900s and 209 wolverines from modern populations in the contiguous U.S. and Canada and combined results with previously published haplotypes. Collectively, these data indicated that historical wolverine populations in the contiguous U.S. were extirpated by the early 20th century, and that modern populations in the contiguous U.S. are likely the descendants of recent immigrants from the north. The Cali1 haplotype previously identified in California museum specimens was also common in historical samples from the southern Rocky Mountains, and likely evolved in isolation in the southern ice-free refugium that encompassed most of the contiguous U.S. during the last glaciation. However, when southern populations were extirpated, these matrilines were eliminated. Several of the other haplotypes found in historical specimens from the contiguous U.S. also occur in modern North American populations, and belong to a group of haplotypes that are associated with the rapid expansion of northern wolverine populations after the last glacial retreat. Modern wolverines in the contiguous U.S. are primarily haplotype A, which is the most common and widespread haplotype in Canada and Alaska. For the translocation of wolverines to California, Colorado, and other areas in the western U.S., potential source populations in the Canadian Rocky Mountains may provide the best mix of genetic diversity and appropriate learned behavior

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

Unaccompanied status as a risk factor in Vietnamese Amerasians

This study prospectively evaluates the relationship between unaccompanied status and levels of psychological distress in a group of Vietnamese Amerasians both prior to, and during, migration. Its objective was to determine whether unaccompanied migrant status functions as an independent post-departure risk factor for psychological distress, or if unaccompanied migrants are already at increased risk for, and have higher levels of, psychological distress prior to departure and the acquisition of unaccompanied status. Seventy-five Vietnamese Amerasian youth were evaluated at two points during their migration utilizing Felsman's Personal Information Form, the Hopkins Symptom Checklist-25, and the Youth Self-Report. The first assessment was conducted prior to migration at the Amerasian Transit Center in Vietnam, and the second during migration at the Philippine Refugee Processing Center. Unaccompanied Amerasians were found to have significantly higher risk levels for, and significantly more symptoms of, psychological distress prior to migration than accompanied Amerasians. During migration the difference in levels of psychological distress between accompanied and unaccompanied Amerasians increased beyond that attributable to predeparture risk levels alone. This significant differential increase in levels of psychological distress among unaccompanied Amerasians is attributable to unaccompanied status. Unaccompanied migrant status thus appears to function both as an independent postdeparture risk factor for psychological distress and also as a marker for increased levels of risk and psychological distress prior to migration.unaccompanied migrants risk factors psychological distress