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Biogenic organic precursors play an important role in atmospheric new particle formation (NPF). One of the major precursor species is α-pinene, which upon oxidation can form a suite of products covering a wide range of volatilities. Highly oxygenated organic molecules (HOMs) comprise a fraction of the oxidation products formed. While it is known that HOMs contribute to secondary organic aerosol (SOA) formation, including NPF, they have not been well studied in newly formed particles due to their very low mass concentrations. Here we present gas- and particle-phase chemical composition data from experimental studies of α-pinene oxidation, including in the presence of isoprene, at temperatures (−50 and −30 ∘C) and relative humidities (20 % and 60 %) relevant in the upper free troposphere. The measurements took place at the CERN Cosmics Leaving Outdoor Droplets (CLOUD) chamber. The particle chemical composition was analyzed by a thermal desorption differential mobility analyzer (TD-DMA) coupled to a nitrate chemical ionization–atmospheric pressure interface–time-of-flight (CI-APi-TOF) mass spectrometer. CI-APi-TOF was used for particle- and gas-phase measurements, applying the same ionization and detection scheme. Our measurements revealed the presence of C8−10 monomers and C18−20 dimers as the major compounds in the particles (diameter up to ∼ 100 nm). Particularly, for the system with isoprene added, C5 (C5H10O5−7) and C15 compounds (C15H24O5−10) were detected. This observation is consistent with the previously observed formation of such compounds in the gas phase. However, although the C5 and C15 compounds do not easily nucleate, our measurements indicate that they can still contribute to the particle growth at free tropospheric conditions. For the experiments reported here, most likely isoprene oxidation products enhance the growth of particles larger than 15 nm. Additionally, we report on the nucleation rates measured at 1.7 nm (J1.7 nm) and compared with previous studies, we found lower J1.7 nm values, very likely due to the higher α-pinene and ozone mixing ratios used in the present study.
Biogenic organic precursors play an important role in atmospheric new particle formation (NPF). One of the major precursor species is α-pinene, which upon oxidation can form a suite of products covering a wide range of volatilities. Highly oxygenated organic molecules (HOMs) comprise a fraction of the oxidation products formed. While it is known that HOMs contribute to secondary organic aerosol (SOA) formation, including NPF, they have not been well studied in newly formed particles due to their very low mass concentrations. Here we present gas- and particle-phase chemical composition data from experimental studies of α-pinene oxidation, including in the presence of isoprene, at temperatures (−50 and −30 ∘C) and relative humidities (20 % and 60 %) relevant in the upper free troposphere. The measurements took place at the CERN Cosmics Leaving Outdoor Droplets (CLOUD) chamber. The particle chemical composition was analyzed by a thermal desorption differential mobility analyzer (TD-DMA) coupled to a nitrate chemical ionization–atmospheric pressure interface–time-of-flight (CI-APi-TOF) mass spectrometer. CI-APi-TOF was used for particle- and gas-phase measurements, applying the same ionization and detection scheme. Our measurements revealed the presence of C8−10 monomers and C18−20 dimers as the major compounds in the particles (diameter up to ∼ 100 nm). Particularly, for the system with isoprene added, C5 (C5H10O5−7) and C15 compounds (C15H24O5−10) were detected. This observation is consistent with the previously observed formation of such compounds in the gas phase. However, although the C5 and C15 compounds do not easily nucleate, our measurements indicate that they can still contribute to the particle growth at free tropospheric conditions. For the experiments reported here, most likely isoprene oxidation products enhance the growth of particles larger than 15 nm. Additionally, we report on the nucleation rates measured at 1.7 nm (J1.7 nm) and compared with previous studies, we found lower J1.7 nm values, very likely due to the higher α-pinene and ozone mixing ratios used in the present study.
Es wird eine systematische Anleitung gegeben zur Revision der Namen von Assoziationen gemäß den Regeln des Internationalen Code der Pflanzensoziologischen Nomenklatur (ICPN, 3. Aufl. 2000). Außerdem werden die Verfahren zur gültigen Veröffentlichung von Assoziationen und Subassoziationen erläutert. Eine Übersicht über die Formen der Autorzitate und Zusätze bei syntaxonomischen Namen ist beigefügt.
Ernst Preising (1911-2007)
(2008)
Senecio inaequidens DC., eine in Mitteleuropa bislang nur von Ruderalstandorten bekannte Art, hat sich neuerdings auf den Ostfriesischen Inseln als fester Bestandteil der natürlichen Dünenvegetation (Elymo-Ammophiletum, Hippophao-Salicetum arenariae)etabliert und sich dort vom Epökophyten zum Agriophyten gewandelt. Auf entsprechenden Standorten wurde die Art bislang auf Borkum, Baltrum, Spiekeroog, Wangerooge, Oldeoog und Mellum gefunden.
Noneequilibrium models (three-fluid hydrodynamics and UrQMD) use to discuss the uniqueness of often proposed experimental signatures for quark matter formation in relativistic heavy ion collisions. It is demonstrated that these two models - although they do treat the most interesting early phase of the collisions quite differently(thermalizing QGP vs. coherent color fields with virtual particles) - both yields a reasonable agreement with a large variety of the available heavy ion data.
Rubus raduloides (ROG.) SUDRE, eine bislang nur von England, Wales und Schottland bekannte Brombeerart, ist ebenso auf dem Kontinent (in den Niederlanden, Belgien und in der Bundesrepublik Deutschland) weit verbreitet, doch hier bisher verkannt und mit anderen Arten verwechselt. Nomenklatorische Fragen, die Verbreitung und Ökologie werden behandelt, und darüber hinaus wird eine detaillierte Beschreibung mit Abbildungen dieser auch in Großbritannien oft falsch interpretierten Art gegeben, um weitere Fehldeutungen zukünftig zu verhindern.
Das Pruno-Rubetum elegantispinosi (Pruno-Rubetalia) wird als neue Gebüschgesellschaft auf kalkreicheren Böden in Hecken Niedersachsens und Westfalens beschrieben. Darüber hinaus wird die Syntaxonomie der Rhamno-Prunetea behandelt. Es wird gezeigt, daß die Rubi (Pseudo-Phanerophyta) mit ihren nur zweijährigen Schößlingen nicht in der Lage sind, sich in geschlossenen, von echten ausdauernden Sträuchern (Nano- Phanerophyta) gebildeten Gebüschen zu behaupten und daher nur als charakteristischer «ubus-Mantel dieser echten Prunetalia-Gebüsche auftreten, wo sie als eine Art "Klammergesellschaft" sowohl die echten Prunetalia wie auch die vorgelagerten Säume (Trifolio- Geranieta, Alliarietalia) zum Teil miteinander verbinden. Im Interesse einer saubereren nyntaxonomischen Fassung der (subatlantischen) Rhamno-Prunetea sind daher (besonders an breiteren Hecken und in ausgedehnteren Gebüschen) innere brombeer- und weitgehend auch krautfreie Bereiche (Prunetalia s.str.) von den äußeren Pruno-Rubetalia zu unters::: heiden, die die Mantelzone der Prunetalia s. str. darstellen, oder auch insgesamt durch schmale Hecken, Waldmänteloder durch noch offene Ptoruerstad.en der Prunetalia s. str. repräsentiert werden können.
Die in Europa vorkommenden Sommergrünen Brombeeren (Rubus subgenus Rubus sectio Rubus subsectio Rubus) werden in vier Serien untergliedert: Series Nessenses H. E. Weber ser. nov. (Typus: Rubus nessensis Hall), Series Rubus ser. nov. (Typus: Rubus fruticosus L. = R. plicatus Weihe & Nees), Series Canadenses (L.H. Bailey) H. E.Weber ser. nov. (Typus: Rubus canadensis L.) und Series Alleghenienses (L. H. Bailey) H. E. Weber ser. nov. (Typus: Rubus allegheniensis Porter). Die Series Rubus wird in zwei Subserien unterteilt: Subseries Rubus (Typus: Rubus fruticosus L.) subser. nov. und Subseries Subrhamnifolii (Focke) H. E. Weber subser. nov. (Typus: Rubus montanus Wirtgen = R. senticosus Koehler ex Weihe). Die Taxonomie und Nomenklatur dieser infragenerischen Taxa sind behandelt.