Bats and frogs and animals in between: evidence for a common central timing mechanism to extract periodicity pitch

Widely divergent vertebrates share a common central temporal mechanism for representing periodicities of acoustic waveform events. In the auditory nerve, periodicities corresponding to frequencies or rates from about 10 Hz to over 1,000 Hz are extracted from pure tones, from low-frequency complex sounds (e.g., 1st harmonic in bullfrog calls), from mid-frequency sounds with low-frequency modulations (e.g., amplitude modulation rates in cat vocalizations), and from time intervals between high-frequency transients (e.g., pulse-echo delay in bat sonar). Time locking of neuronal responses to periodicities from about 50 ms down to 4 ms or less (about 20–300 Hz) is preserved in the auditory midbrain, where responses are dispersed across many neurons with different onset latencies from 4–5 to 20–50 ms. Midbrain latency distributions are wide enough to encompass two or more repetitions of successive acoustic events, so that responses to multiple, successive periods are ongoing simultaneously in different midbrain neurons. These latencies have a previously unnoticed periodic temporal pattern that determines the specific times for the dispersed on-responses.     

Spatial reflection patterns of iridescent wings of male pierid butterflies: curved scales reflect at a wider angle than flat scales

The males of many pierid butterflies have iridescent wings, which presumably function in intraspecific communication. The iridescence is due to nanostructured ridges of the cover scales. We have studied the iridescence in the males of a few members of Coliadinae, Gonepteryx aspasia, G. cleopatra, G. rhamni, and Colias croceus, and in two members of the Colotis group, Hebomoia glaucippe and Colotis regina. Imaging scatterometry demonstrated that the pigmentary colouration is diffuse whereas the structural colouration creates a directional, line-shaped far-field radiation pattern. Angle-dependent reflectance measurements demonstrated that the directional iridescence distinctly varies among closely related species. The species-dependent scale curvature determines the spatial properties of the wing iridescence. Narrow beam illumination of flat scales results in a narrow far-field iridescence pattern, but curved scales produce broadened patterns. The restricted spatial visibility of iridescence presumably plays a role in intraspecific signalling.     

Seasonal reproductive cycles in three commercially exploited fishes from the slope waters off New Zealand

Reproductive cycles were investigated in orange roughy, Hoplostethus atlanticus , smooth oreo, Pseudocyttus maculatus , and black oreo dory, Allocyttus sp., from mid-slope waters (600–1300 m) around New Zealand from 1982 to 1985. Orange roughly displayed a mid-winter spawning period in July and August, whereas both dory species spawned in November and December. In all three species, the timing of spawning was consistent from year to year. Ovarian development in orange roughy and black oreo dory was found to be synchronous, with a single clutch of oocytes being matured for each spawning season. In males, testes of a given macroscopic stage were dominated by a single gamete stage, supporting the existence of a brief rather than prolonged spawning period. The possible relationship of spawning period to seasonal changes in the productivity of the surface water is discussed.     

The posthatch physiology of the turkey poult--II. Hematology

Packed cell volume, total leukocytes, total erythrocytes, hemoglobin, mean cell volume and mean corpuscular hemoglobin concentration of the poult were analyzed daily for the first 10 days posthatch. Sexually dimorphic effects on hematological parameters were not apparent, but there was a sex X day interaction for all parameters except hemoglobin indicating that males were slower to develop/respond to critical stimuli. The study revealed a latency in production of erythrocytes and leukocytes in posthatch males and females which coincided temporally with early poult mortality.     

The effect of sodium chlorate and nitrapyrin on the nitrification mediated nitrosation process in soils

Summary The influence of total nitrification to nitrate or partial nitrification to nitrite on the soil organic nitrogen status was examined. NH ₄ ⁺ –¹⁵N was added to the soil in the absence and the presence of NaClO₃, respectively nitrapyrin. The first chemical inhibits only nitrate formation, the second inhibits total nitrification. The accumulation of nitrite nitrogen in the soil at levels up to 5 mg kg^–1 increased the loss of nitrogen. Yet, it did not increase the binding of mineral nitrogen into soil organic matter, relative to the control soil. The data suggest that the biochemistry of the nitrite formation process, rather than the levels of nitrite ions formed, are of primary importance in the role of nitrification mediated nitrosation of soil organic matter.