Visibility of single atoms

Theoretical and experimental studies indicate that, with a high-resolution scanning electron microscope, it is now possible to obtain pictures of a single heavy atom resting on a thin carbon substrate.     

Scanning electron microscopes: is high resolution possible?

Experiments with this scanning microscope have produced extremely encouraging results so that we feel Confident in predicting high resolution and high contrast after some obvious modifications are made in the system, such as providing a good objective lens. Experience with conventional lenses indicates that the instrument behaves in a predictable manner and there is no reason to doubt that the resolution can be as good as that of a conventional microscope. The use of quadrupole lenses will depend on calculations now being performed. There is cause for optimism; high resolution may also be possible with this kind of lens. Experience with field emission shows that the technology is not difficult and that there is more than enough current available for any conceivable use. Energy-loss measurements have been made on a variety of materials. It is attractive to consider the possibility of chemical analysis of selected areas of a specimen. We believe that a very crude form of analysis may indeed be possible. The principal advantage of the use of energy-loss techniques, however, may be in the availability of another contrast mechanism. The ability to "see" small details may be considerably enhanced. Finally, we are experimenting with the possibility of using transmitted electrons of different energy losses to produce different colors on a color television display. This should add an extra element to the picture contrast which may be of some value.     

Proximity to a forest leads to higher honey yield: Another reason to conserve

Although tropical forest conservation is a top priority for human and environmental health, deforestation persists, mainly because of food and economic needs. No community will totally give up economic activities for the sake of ecological integrity, unless it is given alternative economic activities from which to draw its livelihood. Beekeeping in the forest buffer zone instead of traditional destructive honey-harvesting from forest trees is one such option at Arabuko Sokoke Forest (ASF) in Kenya. ASF is a dry coastal forest which is home to endangered and threatened fauna and is a hotspot considered a priority for conservation. In order to find out whether honey quantity and quality differed with distance from the forest, we studied honey yield per harvest (kg) and obtained samples from hives placed at varying distances from ASF in two successive years. Honey yield increased with proximity to the forest. Indeed the yield almost doubled in hives placed less than 1 km from the forest compared to those placed more than 3 km from the forest. All the honey samples met internationally required quality standards, although sugar levels were at the lower limit. This study demonstrates that the conservation of tropical forest ecosystems can have real local economic benefits. The documentation of the services provided by nearby natural areas should help make conservation of these areas a priority, even for the local communities.     

Comparison of acetate tape impression with squeezing versus skin scraping for the diagnosis of canine demodicosis

This study compared the sensitivity of acetate tape impression and skin squeezing with that of deep skin scraping for the diagnosis of demodicosis in dogs. Demodex canis was detected in 100% of acetate tape impressions obtained after skin squeezing and in 90% of deep skin scrapings. There was a significant difference (P < 0.001) between the techniques in the total number of mites detected. Acetate tape impression with skin squeezing was found to be more sensitive than deep skin scraping and is an alternative diagnostic method for canine demodicosis.     

Snake envenomation in cats and its detection by rapid immunoassay

Objective To determine the usefulness of a snake venom detection kit (SVDK) in the management of envenomed cats.
Design A clinical study.  

Animals

Twenty-two cats were investigated.
Procedure Cats injected subcutaneously with approximately 0.25 or 1.0 lethal dose (LD) of tiger snake venom or 1 or 4 LD of brown snake venom were observed for clinical symptoms of envenomation at intervals over the ensuring 24 to 48 hours(h). Blood and urine samples were taken at regular intervals and assayed in a quantitative laboratory assay for snake venoms. Selected samples were assayed in parallel in a rapid, semi-quantitative SVDK.
Results The studies showed that it was important to estimate the elapsed time from envenomation to presentation. If this time was less than 8 h, blood was the most appropriate sample and a negative result should exclude serious envenomation. If the elapsed time exceeded 8 h, it was essential that urine be sampled. Venom levels in urine were high at 8 h and approached the level of test sensitivity over 24 to 48 h; however by this time clinical signs were obvious in endangered cats.  

Conclusions

Careful use of the SVDK is a valuable aid in the management of a potentially envenomed cat.