Biogenic potassium salt particles as seeds for secondary organic aerosol in the Amazon     

C Pöhlker  KT Wiedemann  B Sinha  M Shiraiwa  SS Gunthe  M Smith  H Su  P Artaxo  Q Chen  Y Cheng  W Elbert  MK Gilles  AL Kilcoyne  RC Moffet  M Weigand  ST Martin  U Pöschl  MO Andreae 《Science (New York, N.Y.)》2012,337(6098):1075-1078

The fine particles serving as cloud condensation nuclei in pristine Amazonian rainforest air consist mostly of secondary organic aerosol. Their origin is enigmatic, however, because new particle formation in the atmosphere is not observed. Here, we show that the growth of organic aerosol particles can be initiated by potassium-salt-rich particles emitted by biota in the rainforest. These particles act as seeds for the condensation of low- or semi-volatile organic compounds from the atmospheric gas phase or multiphase oxidation of isoprene and terpenes. Our findings suggest that the primary emission of biogenic salt particles directly influences the number concentration of cloud condensation nuclei and affects the microphysics of cloud formation and precipitation over the rainforest.  相似文献   

Carbon isotope constraints on the deglacial CO₂ rise from ice cores     

Schmitt J  Schneider R  Elsig J  Leuenberger D  Lourantou A  Chappellaz J  Köhler P  Joos F  Stocker TF  Leuenberger M  Fischer H 《Science (New York, N.Y.)》2012,336(6082):711-714

The stable carbon isotope ratio of atmospheric CO(2) (δ(13)C(atm)) is a key parameter in deciphering past carbon cycle changes. Here we present δ(13)C(atm) data for the past 24,000 years derived from three independent records from two Antarctic ice cores. We conclude that a pronounced 0.3 per mil decrease in δ(13)C(atm) during the early deglaciation can be best explained by upwelling of old, carbon-enriched waters in the Southern Ocean. Later in the deglaciation, regrowth of the terrestrial biosphere, changes in sea surface temperature, and ocean circulation governed the δ(13)C(atm) evolution. During the Last Glacial Maximum, δ(13)C(atm) and atmospheric CO(2) concentration were essentially constant, which suggests that the carbon cycle was in dynamic equilibrium and that the net transfer of carbon to the deep ocean had occurred before then.  相似文献   

Identification of Arcanobacterium (Trueperella) abortisuis, a novel species of veterinary importance, by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS)     

Hijazin M  Ulbegi-Mohyla H  Alber J  Lämmler C  Hassan AA  Timke M  Kostrzewa M  Prenger-Berninghoff E  Weiss R  Zschöck M 《Berliner und Münchener tier?rztliche Wochenschrift》2012,125(1-2):32-37

In the present study A. (T.) abortisuis isolated from pigs and bovines could be reliably identified by determination of phenotypic properties, genotypically by polymerase chain reaction with the help of A. (T.) abortisuis 16s-23S rDNA intergenic spacer region specific oligonucleotide primer and by Matrix-Assisted Laser Desorption Ionization-Time Of Flight mass spectrometry (MALDI-TOF MS). The latter appeared to be a promising tool for fast and cost effective identification of this species and might help to elucidate the role A. (T.) abortisuis plays in infections of pigs, bovines, possibly other animals or humans.  相似文献   

Influence of floor surface and access to pasture on claw health in dairy cows kept in cubicle housing systems     

Haufe HC  Gygax L  Wechsler B  Stauffacher M  Friedli K 《Preventive veterinary medicine》2012,105(1-2):85-92

In this study, the effects on the claw health of dairy cows of three different floor types and access to pasture were investigated on 35 farms. The farms were fitted with a given floor type in the indoor walking area of a cubicle housing system: a solid rubber, mastic asphalt or slatted concrete floor. Because we chose farms on which the given floor type was in good condition, the data presented show what can be achieved on these types of floors under ideal circumstances. Cows on half of the farms per floor type had access to pasture during the grazing period. Each farm was visited three times at approx. 6-month intervals at the end of the winter indoor-housing period and at the end of the summer period, i.e. after the period with access to pasture on half of the farms. During each visit, the claw health of the same 10 cows per farm was assessed on the occasion of routine claw trimming. The proportion of cows with haemorrhages increased from mastic asphalt to rubber and slatted concrete floors. A lower proportion of cows kept on mastic asphalt was affected by white-line fissures and needed intermittent claw-trimming, an indicator for lameness. Cows housed in cubicle systems with slatted concrete floors were at the lowest risk of having heel-horn erosions. Access to pasture was associated with a lower incidence of slight white-line fissures and dermatitis digitalis. A higher proportion of cows with sole haemorrhages and sole ulcers were found on all floor types at the end of the summer period than at the end of the winter indoor-housing period. Floor type did not influence the presence of sole ulcers and deep white-line fissures. In conclusion, the effect of floor type on claw health was slight, and none of the investigated floor types was clearly superior to the others. Access to pasture was not effective in reducing the presence of most types of claw lesions associated with the floor type used in the indoor walking area.  相似文献   

Studies of enzymatic oxidation of TMP-fibers and lignin model compounds by a Laccase–Mediator-System using different 14C and 13C techniques     

Markus Euring  Jerzy Trojanowski  Marina Horstmann  Alireza Kharazipour 《Wood Science and Technology》2012,46(4):699-708

In this work, the results of the enzymatic oxidation of TMP-fibers (thermomechanical pulp) and a well-structured lignin model compound, the dehydropolymer (DHP), were investigated by different ¹⁴C and ¹³C methods, caused by a Laccase–Mediator-System (LMS). These methods are the nuclear magnetic resonance spectroscopy (¹³C-NMR) with DHP (unmarked) and the determination of the ¹⁴CO₂ release of ¹⁴C-marked DHP and TMP-fibers. The ¹³C-NMR measurements were chosen to analyze the structural changes of the LMS-treated DHP model compounds and TMP-fibers qualitatively and quantitatively. The data of ¹⁴CO₂ release give an explanation of the demethylation of DHP and TMP-fibers. The effect of the LMS is shown by comparing the results in respect of DHP and TMP-fibers, which were only treated with laccase and of an inactivated LMS as the control. Comparing the results of the ¹³C-NMR method, in particular the use of the Mediator during the enzymatical treatment, showed significant changes in the structure of the DHP. Also, the TMP-fibers were materially influenced by the LMS. The analysis of the ¹⁴CO₂ release data of the ¹⁴C-marked DHP and TMP-fibers revealed that the rate of ¹⁴CO₂ increases in the ¹⁴C-2 atom as well as in the O¹⁴CH₃ group within the first hour of Laccase–Mediator incubation. Therefore, the ¹⁴CO₂ release from the DHP was higher than from the TMP-fibers.  相似文献   

The landscape matrix modifies the effect of habitat fragmentation in grassland butterflies   总被引：1，自引：0，他引：1  

Erik ?ckinger  Karl-Olof Bergman  Markus Franzén  Tomá? Kadlec  Jochen Krauss  Mikko Kuussaari  Juha P?yry  Henrik G. Smith  Ingolf Steffan-Dewenter  Riccardo Bommarco 《Landscape Ecology》2012,27(1):121-131

The landscape matrix is suggested to influence the effect of habitat fragmentation on species richness, but the generality of this prediction has not been tested. Here, we used data from 10 independent studies on butterfly species richness, where the matrix surrounding grassland patches was dominated by either forest or arable land to test if matrix land use influenced the response of species richness to patch area and connectivity. To account for the possibility that some of the observed species use the matrix as their main or complementary habitat, we analysed the effects on total species richness and on the richness of grassland specialist and non-specialist (generalists and specialists on other habitat types) butterflies separately. Specialists and non-specialists were defined separately for each dataset. Total species richness and the richness of grassland specialist butterflies were positively related to patch area and forest cover in the matrix, and negatively to patch isolation. The strength of the species-area relationship was modified by matrix land use and had a slope that decreased with increasing forest cover in the matrix. Potential mechanisms for the weaker effect of grassland fragmentation in forest-dominated landscapes are (1) that the forest matrix is more heterogeneous and contains more resources, (2) that small grassland patches in a matrix dominated by arable land suffer more from negative edge effects or (3) that the arable matrix constitutes a stronger barrier to dispersal between populations. Regardless of the mechanisms, our results show that there are general effects of matrix land use across landscapes and regions, and that landscape management that increases matrix quality can be a complement to habitat restoration and re-creation in fragmented landscapes.  相似文献   

Chemical profiling of Edelweiss (Leontopodium alpinum Cass.) extracts by micellar electrokinetic capillary chromatography     

Markus Ganzera  Viktoria GreifenederStefan Schwaiger  Hermann Stuppner 《Fitoterapia》2012

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Detection of antibodies to tuberculosis antigens in free-ranging lions (Panthera leo) infected with Mycobacterium bovis in Kruger National Park, South Africa     

Miller M  Joubert J  Mathebula N  De Klerk-Lorist LM  Lyashchenko KP  Bengis R  van Helden P  Hofmeyr M  Olea-Popelka F  Greenwald R  Esfandiari J  Buss P 《Journal of zoo and wildlife medicine》2012,43(2):317-323

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Redoxtrons – An experimental system to study redox processes within the capillary fringe     

Kristof Dorau  Daniel Uteau  Markus Maisch  Andreas Kappler  Stephan Peth  Tim Mansfeldt 《European Journal of Soil Science》2023,74(1):e13347

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The Haematozoa of South African Birds. III. The Carmine Bee-Eater Merops Nubicoides Des Murs and Pucheran     

J.H. Oosthuizen  M.B. Markus 《African Zoology》2013,48(1):99-100

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