Social behavior in hatchling green iguanas: life at a reptile rookery

Hatchling green iguanas (Iguana iguana) emerge from the ground in small groups in a communal nesting area on a small Panamanian islet and engage in complex social interactions. Iguanas from different clutches often join together before and during departure from the nest site. They also usually move around the islet and migrate from it to the larger adjacent landmass in social groups. These and other observations indicate that the sophistication of saurian social organization and neonate behavior has been underestimated.     

Chemical signature of the superconducting phase in the nd-ce-cu-o system

The electron-doped material Nd2-xCexCuO(4) becomes superconducting with a Ce(4+) composition around 0.16, but only after removal of a minuscule amount of extraneous oxygen. This enigmatic behavior was addressed here. A small fraction of copper in the CuO(2) planes of Nd2-xCexCuO(4) was substituted by cobalt-57, which serves as a microprobe of the chemical environment. Deoxygenation brought about little change in the M?ssbauer spectra both above and below the optimal superconducting concentration; however, for x = 0.16 a change was observed. In the latter, a major fraction of the magnetically split, five-coordinate species showed itself as a paramagnetically relaxed doublet upon deoxygenation. The abundance of the paramagnetically relaxed species corresponds closely to the diamagnetic volume fraction and thus provides a microscopic signature of the superconducting phase.     

All-optical nonlinearities in organics

Recognition that organic solids possess some of the largest all-optical nonlinearities of all known materials has resulted in an interdisciplinary effort directed at both the basic understanding and exploitation of these effects. Parallel efforts on ionrganic semiconductors have already reached a mature stage whereby the origin of the effects, together with the prospects for device applications, are well known and appreciated. In this article, a unified picture of nonlinear optical phenomena in both classes of materials is presented. The specific implications for organic-based optical devices are discussed.     

Mars climatology from viking 1 after 20 sols

The results from the meteorology instruments on the Viking 1 lander are presented for the first 20 sols of operation. The daily patterns of temperature, wind, and pressure have been highly consistent during the period. Hence, these have been assembled into 20-sol composites and analyzed harmonically. Maximum temperature was 241.8 degrees K and minimum 187.2 degrees K. The composite wind vector has a mean diurnal magnitude of 2.4 meters per second with prevailing wind from the south and counterclockwise diurnal rotation. Pressure exhibits diurnal and semidiurnal oscillations. The diurnal is ascribed to a combination of effects, and the semidiurnal appears to be the solar semidiurnal tide. Similarities to Earth are discussed. A major finding is a continual secular decrease in diurnal mean pressure. This is ascribed to carbon dioxide deposition at the south polar cap.     

Relating Morphologic and RAPD Marker Varlation to Collection Site Environment in wild Populations of Red Clover (Trifolium Pratense L.)

Although genotypic and phenotypic markers are used to describe genetic diversity, describing patterns of variationattributable to geographic differentiation is complex.We examined concordance between morphologic and RAPDmarker classification of 33 wild red clover populations collected from the Caucasus Mountains, Russia andcompared how morphologic and RAPD markers differed in their correspondence to collection site attributes.Wealso examined if wild red clover populations collected from sites located in areas more conducive to gene flow (i.e.adjacent to roads, or drainage systems) had the same concordance between morphologic and RAPD markers aspopulations collected from sites less conducive to gene flow.We measured 15 morphologic traits in a commongarden and carried out a Random Amplified Polymorphic DNA (RAPD) analysis. There was a significantdifference among the 33 populations for 14 out of 15 morphological traits. Morphology clustered the populationsinto classes that corresponded to three climate regimes. Classification schemes generated by morphologic andRAPD data did not coincide. Morphologic data corresponded with site data for populations collected at all sites.RAPD data corresponded to site data for only those populations collected at sites not conducive to gene flow. Apopulation's adaptation to collection site needs to be considered in using neutral markers to effectivelydiscriminating geographic differentiation.We discuss the practical lessons of this study on the effective collection,conservation and use of plant genetic resources.     

Transient infrared spectroscopy for detection of toxigenic fungi in corn: potential for on-line evaluation

An urgent need for rapid sensors to detect contamination of food grains by toxigenic fungi such as Aspergillus flavus prompted research and development of Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS) as a highly sensitive probe for fungi growing on the surfaces of individual corn kernels. However, the photoacoustic technique has limited potential for screening bulk corn because currently available photoacoustic detectors can accommodate only a single intact kernel at a time. Transient infrared spectroscopy (TIRS), on the other hand, is a promising new technique that can acquire analytically useful infrared spectra from a moving mass of solid materials. Therefore, the potential of TIRS for on-line, noncontact detection of A. flavus contamination in a moving bed of corn kernels was explored. Early test results based on visual inspection of TIRS spectral differences predict an 85% or 95% success rate in distinguishing healthy corn from grain infected with A. flavus. Four unique infrared spectral features which identified infected corn in FTIR-PAS were also found to be diagnostic in TIRS. Although the technology is still in its infancy, the preliminary results indicate that TIRS is a potentially effective screening method for bulk quantities of corn grain.     

A Comparison of Actual and Suggested Digestible Energy Intakes of Miniature Horses Derived from Different Feeding Recommendations

Despite being largely studied as models of equine nutrition, few published data exist on actual nutritional requirements of Miniature horses. Small equines are particularly prone to obesity, insulin resistance, and the metabolic disorders for which these are risk factors. Improper feed rationing, overfeeding in particular, puts horses at risk for these metabolic problems. Feed manufacturers, however, generally supply feeding recommendations for horses weighing ≥360 kg, whereas the average Miniature horse weighs around 100 kg. Lack of nutritional guidelines for small equines makes it difficult for owners to properly estimate the amount of hay and grain to feed their Miniature horse. The purpose of this study was to determine whether feeding recommendations provided by feed manufacturers for average-sized horses could be linearly extrapolated to Miniature horses. This study surveyed nutritional management of 12 mature Miniature horses that represented the ideal body condition of the breed. Each horse’s hay, grain, and pasture intake was recorded and the average daily digestible energy (DE) intake was calculated from those data. The daily DE intake of the surveyed horses was compared with the extrapolated recommendations published by several different sources. When linearly extrapolated to fit the body weight of a Miniature horse, recommendations significantly (P < .002) misestimated the amount of daily DE that the surveyed horses were consuming. The majority of recommendations overestimated the DE consumed by the Miniature horses per day. However, one source that was designed specifically for Miniature horses, severely (P < .001) underestimated their required DE.