Haymaking: A Trip down Memory Lane

On a hot day in August, I climbed into the dust-free air-conditioned cab of a new tractor to assist in a hay baling demonstration during a field day. Hay yield was low as a result of the drought, so it was important that I get everything from the small windrow. I adjusted the volume on the surround sound stereo where I had just inserted a CD of the Eagles Greatest Hits. Now we’re ready to bale – first let me check the GPS and get a check on the moisture of the hay coming into the bale chamber – moisture perfect. Now, let me pull up the local radar on my palm pilot to see if there are any “rain fronts” headed my way. Now, a quick cold drink from the cooler beside the seat and I’m ready to bale hay

Recoverin Regulates Light-dependent Phosphodiesterase Activity in Retinal Rods

The Ca2+-binding protein recoverin may regulate visual transduction in retinal rods and cones, but its functional role and mechanism of action remain controversial. We compared the photoresponses of rods from control mice and from mice in which the recoverin gene was knocked out. Our analysis indicates that Ca2+-recoverin prolongs the dark-adapted flash response and increases the rod's sensitivity to dim steady light. Knockout rods had faster Ca2+ dynamics, indicating that recoverin is a significant Ca2+ buffer in the outer segment, but incorporation of exogenous buffer did not restore wild-type behavior. We infer that Ca2+-recoverin potentiates light-triggered phosphodiesterase activity, probably by effectively prolonging the catalytic activity of photoexcited rhodopsin

Optimizing the vertebrate vestibular semicircular canal: could we balance any better?

The fluid-filled semicircular canals (SCCs) of the vestibular system are used by all vertebrates to sense angular rotation. Despite masses spanning seven decades, all mammalian SCCs are nearly the same size. We propose that the SCC represents a sensory organ that evolution has `optimally designed'. Four geometric parameters are used to characterize the SCC, and `building materials' of given physical properties are assumed. Identifying physical and physiological constraints on SCC operation, we find that the most sensitive SCC has dimensions consistent with available data.Comment: 4 pages, 3 figure

Field Emission and Nanostructure of Carbon Films

The results of field emission measurements of various forms of carbon films are reported. It is shown that the films nanostructure is a crucial factor determining the field emission properties. In particular, smooth, pulsed-laser deposited amorphous carbon films with both high and low sp3 contents are poor field emitters. This is similar to the results obtained for smooth nanocrystalline, sp2-bonded carbon films. In contrast, carbon films prepared by hot-filament chemical vapor deposition (HE-CVD) exhibit very good field emission properties, including low emission turn-on fields, high emission site density, and excellent durability. HF-CVD carbon films were found to be predominantly sp2-bonded. However, surface morphology studies show that these films are thoroughly nanostructured, which is believed to be responsible for their promising field emission properties

Binaral Rivalry in the Presence of Visual Perceptual and Semantic Influences

When two different odorants are presented simultaneously to the two nostrils, we experience alternations in olfactory percepts, a phenomenon called binaral rivalry. Little is known about the nature of such alternations. Here we investigate this issue by subjecting unstable and stable olfactory percepts to the influences of visual perceptual or semantic cues as participants engage in simultaneous samplings of either two different odorants (binaral) or a single odorant and water (mononaral), one to each nostril. We show that alternations of olfactory percepts in the binaral setting persist in the presence of visual perceptual and semantic modulations. We also show that perceptual cues have a stronger effect than semantic cues in the binaral case, whereas their effects are comparable in the mononaral setting. Our findings provide evidence that an inherent, stimulus-driven process underlies binaral rivalry despite its general susceptibility to top-down influences