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Preliminary data on phi production in central Pb + Pb collisions at 158 GeV per nucleon are presented, measured by the NA49 experiment in the hadronic decay channel phi - K+K-. At mid-rapidity, the kaons were separated from pions and protons by combining dE/dx and time-of-flight information; in the forward rapidity range only dE/dx identification was used to obtain the rapidity distribution and a rapidity-integrated mt-spectrum. The mid-rapidity yield obtained was dN/dy = 1.85 ± 0.3 per event; the total phi multiplicity was estimated to be 5.0 ± 0.7 per event. Comparison with published pp data shows a slight, but not very significant strangeness enhancement.
Genera of Cryptognathini (Coleoptera: Coccinellidae) are discussed and a key to all recognized genera is provided. Cryptognatha is revised, and species of this genus are keyed. New species, authored by González and Hanley, are Cryptognatha pam, C. kellie, C. hannah, C. whitney, C. karla, C. celia, C. shelia, C. gayle, C. della and C. vicki. The following new synonymies are proposed: Cryptognatha simillima Sicard = Cryptognatha gemellata Mulsant, Cryptognatha fryii Crotch = Cryptognatha pudibunda Mulsant, Cryptognatha bryanti Brèthes = Cryptognatha pudibunda Mulsant. Lectotypes are here designated for Cryptognatha amicta Gorham, C. weisei Brèthes, C. pudibunda Mulsant and C. fryii Crotch.
Species of Calloeneis Grote (Coleoptera: Coccinellidae) are discussed, and a key to all recognized species is provided. New species described are C. alexandra, C. angelica, C. blanca, C. bennetti, C. bethany, C.brooke, C. francis, C. jacquelin, C. johnnie, C. kara, C. krista, C. leticia, C. lynne, C. robyn, C. marianne, C. myra,C. rosalie, C. roxanne and C. sheri, all authored by Gordon and Hanley.
Twenty new species are described in Pentilia Mulsant (Coleoptera: Coccinellidae: Scymninae: Cryptognathini) by Gordon and González: Pentilia bernadette, P. chelsea, P. dianna, P. elena, P. ernestine, P. estelle, P. kari, P. jasmine, P. jody, P. kendra. P. krystal, P. lora, P. mable, P. muriel, P. nichole, P. nadine. P. paulette, P. rachael, P. sadie and P. traci. A lectotype is here designated for Pentilia egena Mulsant.
Atmospheric aerosols and their effect on clouds are thought to be important for anthropogenic radiative forcing of the climate, yet remain poorly understood1. Globally, around half of cloud condensation nuclei originate from nucleation of atmospheric vapours2. It is thought that sulfuric acid is essential to initiate most particle formation in the atmosphere3,4, and that ions have a relatively minor role5. Some laboratory studies, however, have reported organic particle formation without the intentional addition of sulfuric acid, although contamination could not be excluded6,7. Here we present evidence for the formation of aerosol particles from highly oxidized biogenic vapours in the absence of sulfuric acid in a large chamber under atmospheric conditions. The highly oxygenated molecules (HOMs) are produced by ozonolysis of α-pinene. We find that ions from Galactic cosmic rays increase the nucleation rate by one to two orders of magnitude compared with neutral nucleation. Our experimental findings are supported by quantum chemical calculations of the cluster binding energies of representative HOMs. Ion-induced nucleation of pure organic particles constitutes a potentially widespread source of aerosol particles in terrestrial environments with low sulfuric acid pollution.
Using the NA49 main TPC, the central production of hyperons has been measured in CERN SPS Pb - Pb collisions at 158 GeV c-1. The preliminary ratio, studied at 2.0 < y < 2.6 and 1 < pT < 3 GeV c-1, equals ~ (13 ± 4)% (systematic error only). It is compatible, within errors, with the previously obtained ratios for central S + S [1], S + W [2], and S + Au [3] collisions. The fit to the transverse momentum distribution resulted in an inverse slope parameter T of 297 MeV. At this level of statistics we do not see any noticeable enhancement of hyperon production with the increased volume (and, possibly, degree of equilibration) of the system from S + S to Pb + Pb. This result is unexpected and counterintuitive, and should be further investigated. If confirmed, it will have a significant impact on our understanding of mechanisms leading to the enhanced strangeness production in heavy-ion collisions.