Survey of Predators Associated With European Red Mite (\u3ci\u3ePanonychus Ulmi\u3c/i\u3e; Acari: Tetranychidae) in Ohio Apple Orchards

A survey was conducted to identify the types and relative abundance of predatory arthropods associated with Panonychus ulmi in 21 Ohio apple orchards. Mite populations were sampled by leaf brushing, and insects and spiders were sampled by limb jarring. A state-wide survey was conducted in early July and in late August 1992, and five blocks were evaluated periodically from May until August 1992 at one farm in central Ohio. Predatory mites were detected in only 27% of the blocks surveyed in early July, but in 74% of the blocks surveyed in late August. The ratio of predatory mites to motile P. ulmi was ~0.1 in 20% of blocks in July and in 26% of blocks in August. In commer­cial orchards, the predominant species was Neoseiulus (Amblyseius) fallacis (Acari: Phytoseiidae), but Agistemus fleschneri (Acari: Stigmaeidae) and Zetzellia mali (Acari: Stigmaeidae) were found in several blocks. In orchards monitored throughout the season, N. fallacis was rarely detected until July, and reached the highest density in August when P. ulmi was at a seasonal peak. Important predators of P. ulmi that were detected in limb-jarring samples were Stethorus punctum punctum (Coleoptera: Coccinellidae), green lacewings (Neuroptera: Chrysopidae), the black hunter thrips (Leptothrips mali; Thysanoptera: Phlaeothripidae), and the insidious flower bug (Orius insidiosus; Heteroptera: Anthocoridae). No regional differences were observed in types of predatory mites or insects; the same types were found in all parts of Ohio

Foreword: Animal Law: Thinking About the Future

This foreword touches on some of the challenges animal lawyers and animal advocates face today, then proposes some future directions, both for the field in general and for legal academics in particular

Giffen's Paradox and Falsifiability

This paper considers the methodological problem which the Giffen paradox poses for the economist intent on establishing the empirical status of microeconomic theory. We then turn to more general considerations of the falsifiability of economic theory based on discussions by Adolf Grünbaum. These considerations lead us to reject Louis De Alessi's proposal for rectifying the problem of the Giffen paradox. Finally, we turn to the problem of ceteris paribus as it bears on De Alessi's argument, and observe that he has not resolved this problem.Giffen Paradox, Falsifiability, Microeconomic Theory

The Influence of Carbon Dioxide on Algae Growth

In this laboratory activity students grow Closterium algae in atmospheres that are enriched with, deprived of, or have normal carbon dioxide. Growth is measured by the color intensity of the algae and the production of oxygen gas. This site contains detailed instructions and sample results. Educational levels: Middle school, High school

Ontology: Towards a new synthesis

This introduction to the second international conference on Formal Ontology and Information Systems presents a brief history of ontology as a discipline spanning the boundaries of philosophy and information science. We sketch some of the reasons for the growth of ontology in the information science field, and offer a preliminary stocktaking of how the term ‘ontology’ is currently used. We conclude by suggesting some grounds for optimism as concerns the future collaboration between philosophical ontologists and information scientists

Spatial and Temporal Variations in Interstellar Absorption toward HD 72127AB

New optical spectra of Ca II and Na I toward HD 72127AB provide additional evidence for both spatial and temporal variations in the complex interstellar absorption along the two sight lines; archival UV spectra yield information on the abundances, depletions, and physical conditions in the gas toward HD 72127A. Similarities in the strengths of various tracers of interstellar material in the two lines of sight suggest that the total hydrogen column densities [N(H) ~ 2.5 x 10^{20} cm^{-2}] and the depletions and ionization in the main components at low LSR velocities also are similar. Toward HD 72127A, the main components are relatively cool (T < 900 K), but with depletions resembling those found in warm, diffuse disc clouds; the generally weaker components at higher velocities have much milder depletions, more like those found in halo clouds. Several trace neutral species -- Ca I, Cr I, and Fe I -- are much stronger toward HD 72127B, however. The column density of Cr I, for example, is about 30 times the value determined toward zeta Oph (the only previous detection of that species in the ISM). Dielectronic recombination in warmer gas (T > 5000 K) may be largely responsible for the enhanced abundances of those trace neutral species toward HD 72127B. If the main components toward HD 72127AB are associated with material in the Vela SNR, the differences in abundances and physical conditions occur on scales of about 1100 AU.Comment: 13 pages, 4 figures, accepted to MNRA

Neutral atomic absorption lines and far-UV extinction: Possible implications for depletions and grain parameters

Researchers examine nine lines of sight within the Galaxy and one in the Large Magellanic Cloud (LMC) for which data on both neutral atomic absorption lines (Snow 1984; White 1986; Welty, Hobbs, and York 1989) and far UV extinction (Bless and Savage 1972; Jenkins, Savage, and Spitzer 1986) are available, in order to test the assumption that variations in gamma/alpha will cancel in taking ratios of the ionization balance equation, and to try to determine to what extent that assumption has affected the aforementioned studies of depletions and grain properties