Dynorphin and vasopressin: common localization in magnocellular neurons

The opioid peptide dynorphin is widely distributed in neuronal tissue of rats. By immunocytochemical methods, it was shown previously that dynorphin-like immunoreactivity is present in the posterior pituitary and the cells of the hypothalamic neurosecretory magnocellular nuclei which also are responsible for the synthesis of oxytocin, vasopressin, and their neurophysins. By using an affinity-purified antiserum to the non-enkephalin part of the dynorphin molecule it has now been demonstrated that dynorphin and vasopressin occur in the same hypothalamic cells of rats, whereas dynorphin and oxytocin occur in separate cells. Homozygous Brattleboro rats (deficient in vasopressin) have magnocellular neurons that contain dynorphin separate from oxytocin. Thus dynorphin and vasopressin, although they occur in the same cells, appear to be under separate genetic control and presumably arise from different precursors.     

Integrating Conservation and Financial Objectives on Private Rangelands in Northern Colorado: Rancher and Practitioner Perceptions

Payments for ecosystem services and other approaches seek to expand conservation outcomes from working ranches in rangeland systems. Making these strategies attractive to ranchers and effective in achieving conservation goals requires information that is largely lacking about the human dimensions of aligning conservation, agricultural, and financial objectives on working ranches. This exploratory study addressed this knowledge gap about perceived strategies, barriers, and opportunities by interviewing a purposive sample of 23 ranchers and natural resource practitioners (e.g., government agencies, conservation nonprofits) involved in a collaborative stakeholder group in Larimer County, Colorado. Interviewees’ responses demonstrated a wide range of potential strategies for ranchers to adopt, yet their discussion of ranch-scale and regional concerns demonstrated the multiple interlinked ecological, financial, and social factors that pose challenges for mainstreaming opportunities. All interviewees expressed interest in developing a regional payment for ecosystem services program, seeing an opportunity to simultaneously support ranchers and improve conservation stewardship. However, substantial concerns were expressed regarding possible restrictions to the ranch operation, profitability, and other management and legal factors that would diminish attractiveness to ranchers. Our findings suggest that characteristics of our study system, including proximity to urban areas and the presence of a collaborative stakeholder group, contribute importantly to the opportunities and challenges perceived by interviewees. Furthermore, interviewees’ responses highlighted how factors beyond the ranch-scale can affect the viability of ranch business strategies to achieve conservation and agricultural objectives. Future research with representative populations across rangeland systems in the American West and in contexts with and without collaborative groups will build constructively upon this exploratory study.     

Rapid methods of determining cooling rates of iron and stony iron meteorites

Two rapid and simple methods have been developed for determining the approximate cooling rates of iron and stony-iron meteorites in which kamacite formed by diffusion-controlled growth along planar fronts. The first method requires only measurements of the mean kamacite bandwidth and the bulk nickel content. The second method requires the determination of the nickel composition near the taenite-kamacite interface with an electron microprobe.     

Composition and dynamics of plasma in Saturn's magnetosphere

During Cassini's initial orbit, we observed a dynamic magnetosphere composed primarily of a complex mixture of water-derived atomic and molecular ions. We have identified four distinct regions characterized by differences in both bulk plasma properties and ion composition. Protons are the dominant species outside about 9 RS (where RS is the radial distance from the center of Saturn), whereas inside, the plasma consists primarily of a corotating comet-like mix of water-derived ions with approximately 3% N+. Over the A and B rings, we found an ionosphere in which O2+ and O+ are dominant, which suggests the possible existence of a layer of O2 gas similar to the atmospheres of Europa and Ganymede.     

Ganymede: observations by radar

Radar cross-section measurements indicate that Ganymede scatters to Earth 12 percent of the power expected from a conducting sphere of the same size and distance. This compares with 8 percent for Mars, 12 percent for Venus, 6 percent for Mercury, and about 8 percent for the asteroid Toro. Furthermore, Ganymede is considerably rougher (to the scale of the wavelength used, 12.6 centimeters) than Mars, Venus, or Mercury. Roughness is made evident in this experiment by the presence of echoes away from the center of the disk. A perfectly smooth target would reflect only a glint from the center, whereas a very rough target would reflect power from over the entire disk.