This biennial Review summarizes much of particle physics. Using data from previous editions, plus 2778 new measurements from 645 papers, we list, evaluate, and average measured properties of gauge bosons, leptons, quarks, mesons, and baryons. We also summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as the Standard Model, particle detectors, probability, and statistics. Among the 108 reviews are many that are new or heavily revised including those on CKM quark-mixing matrix, Vud & Vus , Vcb & Vub , top quark, muon anomalous magnetic moment, extra dimensions, particle detectors, cosmic background radiation, dark matter, cosmological parameters, and big bang cosmology. A booklet is available containing the Summary Tables and abbreviated versions of some of the other sections of this full Review. All tables, listings, and reviews (and errata) are also available on the Particle Data Group website: http://pdg.lbl.gov

The production in hadron collisions of a pair of virtual photons, each having a large invariant mass, proceeds via two mechanisms: (a) two independent Drell-Yan-type annihilations of quark pairs in a single interaction and (b) the pair annihilation process q+y*y*.We argue that both mechanisms allow intriguing tests of constituent structure and its associated scaling laws and we show that, despite their a 4 production rate, events of this type are accessible with existing T and proton beams.(Czechoslovak Academy of Science, Institute of Physics, Prague, 1978); I,. Van Hove, SchJadming lecture 1979, Report No. TH. 2628. 4~ultiple-scattering c r o s s sections have been normalized in a similar way by A. Donnachie and P. V. Landshoff, Z. Phys. C 2, 55 (1979).

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We have investigated the dielectrophoretic assembly of colloidal gold, carbon black, and carbon nanotubes into electrical wires. The resulting microwires have diameters less than 1 microm, with lengths ranging from 5 microm to 3 mm. Current-voltage curves for these wires indicate an ohmic response, where the resistance is determined by the type of colloid and by the frequency of the alternating field used to grow the wires. The predicted frequency dependence of dielectrophoresis is confirmed by experiment. Measurements of the threshold voltage for initial wire growth are also presented. These experiments demonstrate that a variety of nanoparticles can be assembled into microwires for sensor applications.

I present data on the time of day of oviposition for 16 species of icterines to evaluate the idea that laying exceptionally early in the morning by the brood parasite, the Brown-headed Cowbird (Molothrus ater), is a specialization for parasitism. This cowbird, the earliest known layer among icterines, typically lays before sunrise (sunrise −9.14 ± 2.52 (SE) min, n = 36). Another brood parasite, the Shiny Cowbird (Molothrus bonariensis), also sometimes lays before sunrise. The best-known nonparasitic icterines, the Red-winged Blackbird (Agelaius phoeniceus) and the Common Grackle (Quisacalus quiscula), lay shortly after sunrise. Fragmentary records show that several other icterines lay within an hour or so after sunrise. Data are inadequate to conclude that early laying by Brown-headed Cowbirds has arisen as an adaptation for parasitism. The Brown-headed Cowbird at London, Ontario, lays earlier than most local passerines, as is shown by new data on oviposition by seven host species arranged in order of increasing lateness of oviposition: Agelaius phoeniceus, Dendroica petechia, Melospiza melodia, Cardinalis cardinalis, Vireo olivaceus, Dumetella carolinensis, and Turdus migratorius.

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We collected 270 female Brown-headed Cowbirds (Molothrus ater) in southern Ontario in 1976 to determine ovarian and oviducal growth during the breeding season and 188 female cowbirds in 1977 to estimate clutch size and the interval between clutches. Ovaries and oviducts grew rapidly in April, reached breeding size in early May, and remained at this size, without regression between clutches, until the end of the breeding season in early July. Ovaries and oviducts then regressed rapidly and by the end of July weighed about the same as those in early April. The clutch size averaged about 4.0-4.6 eggs, similar to clutch sizes of nonparasitic icterids. It varied greatly from 1 egg, in about 10% of the birds, to about 7 eggs. Two days without laying usually separated consecutive clutches, but some birds appeared to miss laying for only 1 day. Although atresia of large yolky follicles was common in birds between clutches, it did not always precede the end of a clutch. The long reproductive period without regression and the short interval between clutches are atypical of passerine reproduction. Rather, the laying cycle of cowbirds is similar to that of domestic chickens (Gallus gallus). The laying cycle of cowbirds seems adapted to a continuous supply of host nests; atresia may be related to a shortage of nests.