Cassini encounters Enceladus: background and the discovery of a south polar hot spot

The Cassini spacecraft completed three close flybys of Saturn's enigmatic moon Enceladus between February and July 2005. On the third and closest flyby, on 14 July 2005, multiple Cassini instruments detected evidence for ongoing endogenic activity in a region centered on Enceladus' south pole. The polar region is the source of a plume of gas and dust, which probably emanates from prominent warm troughs seen on the surface. Cassini's Composite Infrared Spectrometer (CIRS) detected 3 to 7 gigawatts of thermal emission from the south polar troughs at temperatures up to 145 kelvin or higher, making Enceladus only the third known solid planetary body-after Earth and Io-that is sufficiently geologically active for its internal heat to be detected by remote sensing. If the plume is generated by the sublimation of water ice and if the sublimation source is visible to CIRS, then sublimation temperatures of at least 180 kelvin are required.     

A survey of reading, writing, and oral communication skills in North American veterinary medical colleges

In the 1989 report by the Pew National Veterinary Education Program (PNVEP), communication skills topped the list of characteristics the veterinary graduate should possess in order to function effectively in the twenty-first century. To determine the reading, writing, and oral communication requirements and opportunities in veterinary curricula in the US and Canada, and to determine the perceived communication tasks that might be commonly required of practicing veterinarians in the next century, we sent a 15-item communications skills questionnaire to the academic deans of the 31 veterinary curricula in the US and Canada. The results reinforce the importance of communication skills in veterinary medicine, as detailed by the PNVEP over 10 years ago. Based on the responses to our questionnaire and on our own experiences with veterinary medical students, we make several recommendations to enhance communication instruction in veterinary medical curricula.     

Some aspects of the biology and life history of Bothitrema bothi (Monogenea: Bothitrematidae) from the flounder Scophthalmus aquosus (Bothidae) from New Jersey, USA

Bothitrema bothi (MacCallum, 1913), a monopisthocotylean monogenean (Bothitrematidae) found on gills and occasionally on the olfactory rosette within the nares of the bothid flounder, Scophthalmus aquosus (Mitchill, 1815), is distributed along the Atlantic coast of the USA from Woods Hole, Massachusetts to Delaware Bay. This study details aspects of the morphology, microecology and biology of the oncomiracidium, juvenile and adult. Adult worms occur almost exclusively between rakers on the first and second gill arches while juveniles occupy secondary gill filaments. Analysis of variance revealed significant arch, side and position effects. Worm attachment and position is maintained largely by suction generated by a circular seal using its 54 radially arranged accessory haptoral sclerotised elements and a marginal valve. A small anterior appendix with two marginal hooks lies dorsal to a deep anteromedian cleft in the haptor, which, together with wall muscles, creates and releases the negative pressure required for attachment. Four pairs of gland openings in the ventrolateral margins of the anterior adhesive area produce secretions for attachment. Operculate eggs with four rounded protuberances and a filament are laid individually at four-minute intervals at 22 degrees C. Hatching occurs in five days at 20 degrees C. Oncomiracidia have two pairs of eyes, with the posterior pair fused, show both positive and negative phototaxis and swim at a mean rate of 5.2 mm/s at 22 degrees C. Larvae have a circle of 16 hooks and a pair of hamulus primordia. Other accessory haptoral sclerotised structures arise de novo in juveniles after attachment to the host. These data will help to resolve more clearly the relationships of the Bothitrematidae within the Monopisthocotylea.     

Hydrogen peroxide on the surface of Europa

Spatially resolved infrared and ultraviolet wavelength spectra of Europa's leading, anti-jovian quadrant observed from the Galileo spacecraft show absorption features resulting from hydrogen peroxide. Comparisons with laboratory measurements indicate surface hydrogen peroxide concentrations of about 0.13 percent, by number, relative to water ice. The inferred abundance is consistent with radiolytic production of hydrogen peroxide by intense energetic particle bombardment and demonstrates that Europa's surface chemistry is dominated by radiolysis.     

Acid rain: Threshold of leaf damage in eight plant species from a Southern Appalachian forest succession

Eight plant species were subjected to artifical acid rains of pH 2.5, 2.0, 1.5, 1.0 and 0.5 in order to determine the threshold for and symptoms of damage. The plants were Erechtites, Robinia, Pinus, Quercus, Carya, Liriodendron, Acer and Corpus from the Coweeta Hydrologic Laboratory near Franklin, North Carolina Droplets of pH 2.0 produced brown necrotic spots on all species except Pinus while droplets of pH 1.0 produced necroses on leaves of all species examined. The size of necrotic spots increased with increasing acidity. Comparison of these results with the literature suggests that developing leaves are more easily damaged than are the mature leaves used in this study. The volume weighted average rainfall pH for Coweeta is 4.6 with observations ranging from 3.2 to 5.9. Results of this study suggest that a 10-fold increase in acidity from pH 3.2 to 2.2 in a single spring or summer storm could bring damage or death to mature leaves of dominant flowering plants in the Southern Appalachians.     

Occurrence of resveratrol in edible peanuts

Resveratrol has been associated with reduced cardiovascular disease and reduced cancer risk. This phytoalexin has been reported in a number of plant species, including grapes, and may be one of the compounds responsible for the health benefits of red wine. Analytical methods for measuring resveratrol in wine and peanuts were adapted to isolate, identify, and quantify resveratrol in several cultivars of peanuts. Aqueous ethanol (80% v/v) extracts from peanuts without seed coats were purified over alumina/silica gel columns and analyzed by reversed phase HPLC using a C-18 column. Peanuts from each market type, Virginia, runner, and Spanish, produced in four different locations contained from 0.03 to 0.14 microg of resveratrol/g. Seed coats from runner and Virginia types contained approximately 0.65 microg/g of seed coat, which is equivalent to <0.04 microg/seed. Quantitative analysis of 15 cultivars representing 3 peanut market types, which had been cold stored for up to 3 years, indicated a range of 0.02-1.79 microg/g of peanut compared to 0.6-8.0 microg/mL in red wines.