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Rare species have long exerted a particular fascination for many botanists. The reasons for this are discussed, as are the justifications for the scientific study of rare and threatened species. A high proportion of the threatened species currently on the Schedules of threatened species in New South Wales were first collected by the earliest botanical explorers. Possible reasons for their success in finding rare species are speculated upon.
Legislative requirements for the identification of threatened species have arisen under the Biodiversity Convention, and the particular regime established by the New South Wales Threatened Species Conservation Act 1995 is described. Features of the plants currently included on the New South Wales Schedules are discussed and the question as to whether they are affected by a variety of recording biases is examined. The consequences of listing for the long term conservation of threatened species are explored.
We report the first measurement of strange ( Lambda ) and antistrange ( Lambda -bar) baryon production from sqrt[sNN]=130 GeV Au+Au collisions at the Relativistic Heavy Ion Collider (RHIC). Rapidity density and transverse mass distributions at midrapidity are presented as a function of centrality. The yield of Lambda and Lambda -bar hyperons is found to be approximately proportional to the number of negative hadrons. The production of Lambda -bar hyperons relative to negative hadrons increases very rapidly with transverse momentum. The magnitude of the increase cannot be described by existing hadronic string fragmentation models alone.
Inclusive transverse momentum distributions of charged hadrons within 0.2<pT<6.0 GeV/c have been measured over a broad range of centrality for Au+Au collisions at sqrt[sNN]=130 GeV. Hadron yields are suppressed at high pT in central collisions relative to peripheral collisions and to a nucleon-nucleon reference scaled for collision geometry. Peripheral collisions are not suppressed relative to the nucleon-nucleon reference. The suppression varies continuously at intermediate centralities. The results indicate significant nuclear medium effects on high-pT hadron production in heavy-ion collisions at high energy.
We report STAR results on the azimuthal anisotropy parameter v2 for strange particles K0S, Lambda , and Lambda -bar at midrapidity in Au+Au collisions at sqrt[sNN]=130 GeV at the Relativistic Heavy Ion Collider. The value of v2 as a function of transverse momentum, pt, of the produced particle and collision centrality is presented for both particles up to pt~3.0 GeV/c. A strong pt dependence in v2 is observed up to 2.0 GeV/c. The v2 measurement is compared with hydrodynamic model calculations. The physics implications of the pt integrated v2 magnitude as a function of particle mass are also discussed.
Elliptic flow holds much promise for studying the early-time thermalization attained in ultrarelativistic nuclear collisions. Flow measurements also provide a means of distinguishing between hydrodynamic models and calculations which approach the low density (dilute gas) limit. Among the effects that can complicate the interpretation of elliptic flow measurements are azimuthal correlations that are unrelated to the reaction plane (nonflow correlations). Using data for Au + Au collisions at sqrt[sNN]=130 GeV from the STAR time projection chamber, it is found that four-particle correlation analyses can reliably separate flow and nonflow correlation signals. The latter account for on average about 15% of the observed second-harmonic azimuthal correlation, with the largest relative contribution for the most peripheral and the most central collisions. The results are also corrected for the effect of flow variations within centrality bins. This effect is negligible for all but the most central bin, where the correction to the elliptic flow is about a factor of 2. A simple new method for two-particle flow analysis based on scalar products is described. An analysis based on the distribution of the magnitude of the flow vector is also described.
We report the first observation of K*(892)0--> pi K in relativistic heavy ion collisions. The transverse momentum spectrum of (K*0+K*0)/2 from central Au+Au collisions at sqrt[sNN]=130 GeV is presented. The ratios of the K*0 yield derived from these data to the yields of negative hadrons, charged kaons, and phi mesons have been measured in central and minimum bias collisions and compared with model predictions and comparable e+e-, pp, and p-barp results. The data indicate no dramatic reduction of K*0 production in relativistic heavy ion collisions despite expected losses due to rescattering effects.
The STAR Collaboration reports the first observation of exclusive rho 0 photoproduction, AuAu-->AuAu rho 0, and rho 0 production accompanied by mutual nuclear Coulomb excitation, AuAu-->Au [star] Au [star] rho 0, in ultraperipheral heavy-ion collisions. The rho 0 have low transverse momenta, consistent with coherent coupling to both nuclei. The cross sections at sqrt[sNN]=130 GeV agree with theoretical predictions treating rho 0 production and Coulomb excitation as independent processes.
We present the first measurement of midrapidity vector meson phi production in Au+Au collisions at RHIC (sqrt[sNN]=130 GeV) from the STAR detector. For the 11% highest multiplicity collisions, the slope parameter from an exponential fit to the transverse mass distribution is T=379±50(stat)±45(syst) MeV, the yield dN/dy=5.73±0.37(stat)±0.69(syst) per event, and the ratio N phi /Nh- is found to be 0.021±0.001(stat)±0.004(syst). The measured ratio N phi /Nh- and T for the phi meson at midrapidity do not change for the selected multiplicity bins.
Die floristische Untersuchung epiphytischer Moose auf Stämmen der Baumfarne Cyathea arborea und Dicksonia sellowiana belegt eine große Artenvielfalt von Laub- und Lebermoosen. Von insgesamt 142 Arten wurden 20 in mehr als 10 % der Aufnahmen nachgewiesen; 77 Arten kamen nur 1 bis 3 mal vor. Es wurden fünf neue Assoziationen in zwei neuen Ordnungen beschrieben: Die Assoziationen der Ordnung Hymenodontetalia aeruginosae (Syrrhopodetum proliferi, Porotricho-Syrrhopodetum incompleti und Orthostichello-Syrrhopodetum parasitici) kommen fast ausschließlich auf Cyathea arborea vor. Sie bevorzugen luftfeuchte Habitate in Küstenregenwäldern, Nebelwäldern und in Feuchtwäldern landeinwärts der Küstengebirge. Das Campylopodetum extincti und das Campylopodetum occulti aus der neuen Ordnung Syrrhopodetetalia gaudichaudii bevorzugen Dicksonia sellowiana als Phorophyt. Daher trifft man diese Assoziationen hauptsächlich auf dem Planalto der südlichen Staaten Brasiliens an, wo Araukarienwald vorherrschend ist. In beiden Ordnungen sind die beherrschenden Wuchsformen Filze und Decken (meist Lebermoose). Die charakteristischen Elemente der Hymenodetetalia aeruginosae waren die Kurzrasen und vom Substrat abstehende Lebensformen (Bäumchen, Wedel, Schweif). Für die Ordnung Syrrhopodetetalia gaudichaudii sind dagegen die Kurzrasen-Polster-Mischform und Hochrasen typisch, die sich v.a. aus Camyplopus- und Syrrhopodon-Arten zusammensetzen.