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The collision between a Ba atom and an Arn cluster carrying N2O molecules has been investigated under crossed molecular beam conditions. The argon cluster acts as a solvent for the Ba+N2O reaction, which is monitored through its chemiluminescent channel forming electronically excited BaO. The effects of cluster size and the number of N2O molecules per cluster have been investigated systematically as have the effects of extra molecules present upon the cluster (CH4). It has been shown that (i) the BaO reaction product either stays solvated in the cluster or is lost from the cluster; (ii) the reaction probability between Ba and N2O is approximately unity for the clusters considered here; (iii) the chemiluminescence quantum yield decreases as the number of N2O molecules per cluster is increased. The effect of a thermal bath (the argon cluster) on the dynamics of the well studied gas phase reaction Ba+N2O is discussed. [ABSTRACT FROM AUTHOR]

Water-soluble phytochemicals produced by invasive plants may represent novel elements of invaded ecosystems that can precipitate a variety of direct and indirect effects on native organisms. Phenolic compounds in particular are a common plant defense, and these compounds may have disproportionate impacts on amphibians compared to other taxa. We coupled an exploration of invasive plant extract effects on larvae of four amphibian species (the salamander Ambystoma maculatum, the toad Anaxyrus americanus, and the frogs Hyla sp. and Lithobates blairi) with behavioral observations designed to determine whether behavior can ameliorate the negative effects of exposure to invasive plant extracts. Larvae were reared in extracts of the widespread invasive Amur honeysuckle ( Lonicera maackii), mixed native leaf litter, and a water control. Anaxyrus americanus tadpoles reared in L. maackii extracts were more likely to die than tadpoles reared in native extracts, but differences in mortality following rearing in native and exotic extracts were not significant for the other three species. Anaxyrus americanus and L. blairi tadpoles made more trips to the surface in L. maackii extracts than in native extracts, consistent with the hypothesis that exotic extracts may interfere with respiratory physiology and suggesting that L. blairi can behaviorally ameliorate the negative effects of L. maackii extracts. Our study highlights both a direct and indirect pathway by which invasive plant extracts may alter the ecological dynamics of native fauna. [ABSTRACT FROM AUTHOR]

The hydroid fauna of the Galápagos Islands, Ecuador, is known largely from reports of collections made between 1932 and 1938 during several Allan Hancock Pacific Expeditions. Of some 100 nominal species (excluding Stylasteridae) reported from the archipelago overall, including species obtained during other expeditions, 81 are recognized as valid. An additional 15 species are added here, 14 of them based on collections undertaken between 1992 and 2000. Leptothecates account for 66 of the 96 species, while anthoathecates comprise the remaining 30. One previously undescribed leptothecate, Halopteris violae , sp. nov., is characterized and compared with H. tenella (Verrill, 1874) and H. minuta (Trebilcock, 1928), species it closely resembles. Gonothecae of Sertularella costata Leloup, 1940 are described for the first time. Plumularia galapagensis , nom. nov., is proposed as a replacement name for the invalid junior primary homonym Plumularia tenuissima Fraser, 1938b (not Plumularia tenuissima Totton, 1930). Under provisions of the International Code of Zoological Nomenclature, the widely used name Cladocoryne floccosa Rotch, 1871 is designated a nomen protectum and assigned precedence over its largely unknown senior synonym Hydra corynaria Bosc, 1797, which is reduced to the status of nomen oblitum. Balella irregularis (Fraser, 1938) from the Galápagos is considered conspecific with Balella mirabilis (Nutting, 1905) from Hawaii and Japan. Six new combinations are introduced: Bimeria laxa Fraser, 1938a is assigned to the genus Garveia Wright, 1859, as G . laxa (Fraser, 1938a); Tubularia integra Fraser, 1938a is assigned to Ectopleura L. Agassiz, 1862, as E . integra (Fraser, 1938a); Campanulina ramosa Fraser, 1938a is assigned to Opercularella Hincks, 1868, as O . ramosa (Fraser, 1938a); Bonneviella minor Fraser, 1938a is assigned to Scandia Fraser, 1912, as S . minor (Fraser, 1938a); Campanularia gracilicaulis Fraser, 1938a is assigned to Clytia Lamouroux... [ABSTRACT FROM AUTHOR]

Highlights the various uses of the computer, notably `desktop publishing.' How `desktop publishing' works; Author's book `Signal to Noise' was delivered to the printer on three floppy disks from which camera-ready photostats were generated; Future opportunities for artists' books; More.

The numerator relationship matrix describes the genetic relationships between individuals of a population. Its inverse is used for the prediction of breeding values, as outlined by Henderson (1975a). For large populations, the recursive method commonly used is difficult to apply because of the size of the relationship matrix. Recently Henderson (1975b) derived a method which allows computing the inverse of the numerator relationship matrix itself for a large number of animals, provided the population is non-inbred. The method presented here is an extension of Henderson's method to allow for inbreeding with large number of animals. It takes inbreeding into account and computes the numerator relationship matrix as well as its inverse. The method is particularly efficient in computer storage in that it allows handling of sets of animals larger than 5000 animals, and is almost as fast as the recursive method. [ABSTRACT FROM AUTHOR]

A series of tuned reeds are mounted so that they may be electromagnetically driven. Each reed carries a small concave mirror with which light from an illuminated slit is brought to a focus on a screen. These slit images are lined up in the order of the reed frequencies. When a current having a complex wave, such as the speech current from a microphone, is passed through the electromagnet, the reeds and in consequence the slit images on the screen will oscillate. The driving system and the reeds are so designed that the amplitude of oscillation of each image is proportional to the strength of the corresponding harmonic component in the driving current. Therefore, by observing or photographing the slit image amplitudes, the frequencies and the relative energy content of the components of a complex current may be determined. A spectrometer of this type covering a small frequency range (50 to 3109 cycles) was built for demonstration purposes. The range of such an instrument can be extended to higher and lower frequencies. [ABSTRACT FROM AUTHOR]

Motivation has long been important, if often implicit, in economic analysis. In our particular economic system, featuring the business firm, managerial motivation is of special importance. Yet, few attempts have been made to systematically study managerial motivation, to isolate the factors that may influence and condition such motivation, and to bring economic motivation into the orbit of motivation generally. Establishing managerial motivation by assumption rather than by empirical means has become somewhat difficult to justify. Evidence of a variety of managerial goals continues to accumulate. Our changing social and political institutions and attitudes have carried obvious motivational implications and the economic theory and public policy predicated upon a single simple motivation have recently been subject to critical re-examination. Meanwhile the concepts and researches of social psychology, sociology, cultural anthropology, clinical psychology, and psychiatry have made available new findings, approaches and techniques relative to motivation.

This article presents information on Light Leaf Spot disease of brassicae species, caused by the fungus Gloeosporium concentricum. The disease may occur on any above-ground part of the plant, although generally on the older leaves. Both upper and lower leaf surfaces may be attacked, principally between the veins, but the veins also may be affected. The first sign of the disease is the appearance of a number of snowy-white spots, each usually less than 1 millimeter in diameter and generally arranged in concentric circles, giving the appearance of a spray deposit. The white spots are spore masses produced by sub-cuticular acervuli. As the disease progresses and further spots are formed towards the margin of the affected area, the central part acquires a characteristic dull, bleached, fawn color.

This paper describes an improved method of recording sound magnetically on steel tape, similar in principle to that of the Poulsen telegraphone. By making use of perpendicular instead of longitudinal magnetization, the speed of the tape may be reduced as low as 8 inches per second for recording speech. The low tape speed eliminates many of the difficulties encountered with those systems which made use of longitudinal magnetization. The ratio of the signal to the background noise has been substantially reduced. The recording medium is a steel tape having a thickness of about 2 mils and a width of about 50 mils. A small recording and reproducing machine will be demonstrated. [ABSTRACT FROM AUTHOR]

This chronograph was developed for use in recording the loudness of blows from piano hammers as an artist is making an Ampico record. It records accurately the velocity of each hammer at the moment it strikes the strings. The chronograph, which is of the spark type, records on either stationary or slowly moving paper. A cylindrical drum with a spiral conductor distributes the time interval sparks at right angles to the motion of the paper. A new method of making visible the spot, where the secondary spark punctures the paper, is described. This method permits the use of a very feeble current. A secondary spark energy sufficient to puncture the paper is all that is needed. The punctured spot may be made visible regardless of its size. A simplified electrical circuit for producing the secondary spark is described. Curves and data are given showing the relationship between the velocity of the hammer and the loudness of the piano tone in sesation units. The chronograph with its auxiliary system of recording feeble sparks is applicable to many fields of scientific investigation. [ABSTRACT FROM AUTHOR]