| 1. |
- Aartsen, M. G., et al.
(författare)
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The IceCube Neutrino Observatory : instrumentation and online systems
- 2017
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Ingår i: Journal of Instrumentation. - : IOP PUBLISHING LTD. - 1748-0221. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- The IceCube Neutrino Observatory is a cubic-kilometer-scale high-energy neutrino detector built into the ice at the South Pole. Construction of IceCube, the largest neutrino detector built to date, was completed in 2011 and enabled the discovery of high-energy astrophysical neutrinos. We describe here the design, production, and calibration of the IceCube digital optical module (DOM), the cable systems, computing hardware, and our methodology for drilling and deployment. We also describe the online triggering and data filtering systems that select candidate neutrino and cosmic ray events for analysis. Due to a rigorous pre-deployment protocol, 98.4% of the DOMs in the deep ice are operating and collecting data. IceCube routinely achieves a detector uptime of 99% by emphasizing software stability and monitoring. Detector operations have been stable since construction was completed, and the detector is expected to operate at least until the end of the next decade.
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| 2. |
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| 3. |
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| 4. |
- Roldin, Pontus, et al.
(författare)
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Modelling the contribution of biogenic volatile organic compounds to new particle formation in the Julich plant atmosphere chamber
- 2015
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Ingår i: Atmospheric Chemistry and Physics. - : Copernicus GmbH. - 1680-7324. ; 15:18, s. 10777-10798
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Tidskriftsartikel (refereegranskat)abstract
- We used the Aerosol Dynamics gas- and particle-phase chemistry model for laboratory CHAMber studies (ADCHAM) to simulate the contribution of BVOC plant emissions to the observed new particle formation during photooxidation experiments performed in the Julich Plant-Atmosphere Chamber and to evaluate how well smog chamber experiments can mimic the atmospheric conditions during new particle formation events. ADCHAM couples the detailed gas-phase chemistry from Master Chemical Mechanism with a novel aerosol dynamics and particle phase chemistry module. Our model simulations reveal that the observed particle growth may have either been controlled by the formation rate of semi- and low-volatility organic compounds in the gas phase or by acid catalysed heterogeneous reactions between semi-volatility organic compounds in the particle surface layer (e.g. peroxyhemiacetal dimer formation). The contribution of extremely low-volatility organic gas-phase compounds to the particle formation and growth was suppressed because of their rapid and irreversible wall losses, which decreased their contribution to the nano-CN formation and growth compared to the atmospheric situation. The best agreement between the modelled and measured total particle number concentration (R-2 > 0.95) was achieved if the nano-CN was formed by kinetic nucleation involving both sulphuric acid and organic compounds formed from OH oxidation of BVOCs.
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| 5. |
- Appleton, O, et al.
(författare)
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The next-generation ARC middleware
- 2010
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Ingår i: ANNALS OF TELECOMMUNICATIONS-ANNALES DES TELECOMMUNICATIONS. - : Presses Polytechniques Romandes. - 0003-4347 .- 1958-9395. ; 65:11-12, s. 771-776
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Tidskriftsartikel (refereegranskat)abstract
- The Advanced Resource Connector (ARC) is a light-weight, non-intrusive, simple yet powerful Grid middleware capable of connecting highly heterogeneous computing and storage resources. ARC aims at providing general purpose, flexible, collaborative computing environments suitable for a range of uses, both in science and business. The server side offers the fundamental job execution management, information and data capabilities required for a Grid. Users are provided with an easy to install and use client which provides a basic toolbox for job- and data management. The KnowARC project developed the next-generation ARC middleware, implemented as Web Services with the aim of standard-compliant interoperability.
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| 8. |
- Priestley, Michael, et al.
(författare)
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Chemical characterisation of benzene oxidation products under high- and low-NOx conditions using chemical ionisation mass spectrometry
- 2021
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Ingår i: Atmospheric Chemistry and Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 21:5, s. 3473-3490
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Tidskriftsartikel (refereegranskat)abstract
- Aromatic hydrocarbons are a class of volatile organic compounds associated with anthropogenic activity and make up a significant fraction of urban volatile organic compound (VOC) emissions that contribute to the formation of secondary organic aerosol (SOA). Benzene is one of the most abundant species emitted from vehicles, biomass burning and industry. An iodide time-of-flight chemical ionisation mass spectrometer (ToF-CIMS) and nitrate ToF-CIMS were deployed at the Julich Plant Atmosphere Chamber as part of a series of experiments examining benzene oxidation by OH under high- and low-NOx conditions, where a range of organic oxidation products were detected. The nitrate scheme detects many oxidation products with high masses, ranging from intermediate volatile organic compounds (IVOCs) to extremely low volatile organic compounds (ELVOCs), including C-12 dimers. In comparison, very few species with C->= 6 and O-> 8 were detected with the iodide scheme, which detected many more IVOCs and semi-volatile organic compounds (SVOCs) but very few ELVOCs and low volatile organic compounds (LVOCs). A total of 132 and 195 CHO
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| 9. |
- Nap, M, et al.
(författare)
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Specificity and affinity of monoclonal antibodies against carcinoembryonic antigen.
- 1992
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Ingår i: Cancer Research. - 0008-5472 .- 1538-7445. ; 52:8, s. 2329-39
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Tidskriftsartikel (refereegranskat)abstract
- The binding specificities of 52 well-characterized monoclonal antibodies (Mabs) against carcinoembryonic antigen (CEA) from 12 different research groups were studied by immunohistochemistry and immuno flow cytometry. In addition, the binding constant for the interaction between Mab and CEA was determined by a solution-phase assay. Cryostat sections of colon carcinoma and normal colon, stomach, liver, pancreas, and spleen were studied by immunohistochemistry. Peripheral blood granulocytes, monocytes, and lymphocytes were assayed by immuno flow cytometry. The Mabs used here have previously been classified into five essentially nonoverlapping epitope groups (GOLD 1-5) (Cancer Res., 49: 4852-4858, 1989). Most Mabs cross-reacted with different normal tissues, ranging from highly cross-reactive Mabs (positive reaction with 8 of 9 discriminating tissues) to relatively specific Mabs (positive reaction with 1 of 9 discriminating tissues). Five Mabs (10%) were specific, reacting only with colon carcinoma, normal colon mucosa, and normal gastric foveola. There was a correlation between epitope group and binding specificity. Mabs with a high degree of CEA specificity almost exclusively belonged to epitope groups 1, 2, and 3, while highly cross-reactive Mabs belonged to epitope groups 4 and 5. There was no correlation between antibody specificity and affinity for CEA. Specific Mabs with high as well as low affinity were found.
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| 11. |
- Arino, I., et al.
(författare)
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On the relation between surface texture and gloss of injection-molded pigmented plastics
- 2005
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Ingår i: Polymer Engineering and Science. - : Wiley. - 0032-3888 .- 1548-2634. ; 45:10, s. 1343-1356
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Tidskriftsartikel (refereegranskat)abstract
- The relation between the surface topography of injection-molded plastic objects with deliberately imposed textures and their gloss, measured by means of a conventional glossmeter at incident angles of 20 degrees, 60 degrees and 85 degrees, was investigated. A modification of the general scalar Kirchhoff approximation, which accounts for geometrical features of the glossmeter, is used to describe the experimental gloss values of the textured surfaces. The agreement between the measured and the calculated values for incidence angles of 20 degrees and 60 degrees confirms the usefulness of the approach, though several of the textured surfaces used here are too rough for the Kirchhoff theory to be strictly valid. A poorer agreement, however, was noted at higher incidence angles (85 degrees in this case). For very smooth surfaces (without any texture), the classical Bennett-Porteus theory could in many cases describe the gloss level with sufficient accuracy. The influence on the measured gloss of the polymer material (in terms of its refractive index) and the color of the injection-molded object is also discussed. Light beige specimens in three different polymeric materials (acrylonitrile-butadiene-styrene, acrylonitrile-butadiene-styrene/polycarbonate blend, and polypropylene) as well as three acrylonitrile-butadiene-styrene products with different colors were used. The refractive index of the polymer had no major influence on the measured gloss. The gloss level increased slightly with increasing lightness of the specimens, which can be associated with an increased contribution from the bulk scattering. However, the surface texture governed most of the gloss variations.
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| 12. |
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| 13. |
- Geiger, Jennifer M.O., et al.
(författare)
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Molecular phylogenetic relationships of Cibotium and origin of the Hawaiian endemics
- 2013
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Ingår i: American Fern Journal. - : American Fern Society. - 0002-8444 .- 1938-422X. ; 103:3, s. 141-152
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Tidskriftsartikel (refereegranskat)abstract
- The tree fern genus Cibotium comprises nine species distributed in tropical regions of Asia, Mesoamerica, and the Hawaiian Islands. The four Hawaiian species are endemic to the Hawaiian Islands. The goals of this paper were to determine the relationships among the Cibotium species, determine whether the Hawaiian species are monophyletic, and infer the dispersal pathway likely responsible for delivering an ancestral Cibotium species to the Hawaiian Islands. Molecular phylogenetic analyses based on four coding and five non-coding plastid DNA sequences supported Hawaiian Cibotium as monophyletic, suggesting a single colonization of the Hawaiian Islands. Hawaiian Cibotium are most closely related to species in Mesoamerica. If the ancestor of Hawaiian Cibotium dispersed to the Hawaiian Islands via wind dispersed spores, our analyses suggest the trade winds or storms delivered spores from Mesoamerica or the Hawaiian Islands were colonized first by a species from Asia, followed by subsequent dispersal to Mesoamerica from Hawai'i. Our analyses do not allow us to favor one hypothesis over the other.
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| 14. |
- Lopez-Hilfiker, F. D., et al.
(författare)
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A novel method for on-line analysis of gas and particle composition: description and evaluation of a Filter Inlet for Gases and AEROsols (FIGAERO)
- 2013
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Ingår i: Atmospheric Measurement Techniques Discussions. - : Copernicus Publications. - 1867-8610. ; 6:5, s. 9347-9395
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Tidskriftsartikel (refereegranskat)abstract
- We describe a novel inlet that allows measurement of both gas and particle molecular composition when coupled to mass spectrometric, chromatographic, or optical sensors: the Filter Inlet for Gas and AEROsol (FIGAERO). The design goals for the FIGAERO are to allow unperturbed observation of ambient air while simultaneously analyzing gases and collecting particulate matter on a Teflon filter via an entirely separate sampling port. The filter is analyzed periodically by the same sensor on hourly or faster timescales using temperature-programmed thermal desorption. We assess the performance of the FIGAERO by coupling it to a high-resolution time-of-flight chemical-ionization mass spectrometer (HRToF-CIMS) in laboratory chamber studies of α-pinene oxidation and field measurements at a boreal forest location. Low instrument backgrounds give detection limits of ppt or lower for compounds in the gas-phase and in the pg m−3 range for particle phase compounds. The FIGAERO-HRToF-CIMS provides molecular information about both gases and particle composition on the 1 Hz and hourly timescales, respectively for hundreds of compounds. The FIGAERO thermal desorptions are highly reproducible (better than 10%), allowing a calibrated assessment of the effective volatility of desorbing compounds and the role of thermal decomposition during the desorption process. We show that the often multi-modal desorption thermograms arising from secondary organic aerosol (SOA) provide additional insights into molecular composition and/or particle morphology, and exhibit changes with changes in SOA formation or aging pathways.
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| 15. |
- Lopez-Hilfiker, F. D., et al.
(författare)
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A novel method for online analysis of gas and particle composition: description and evaluation of a Filter Inlet for Gases and AEROsols (FIGAERO)
- 2014
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Ingår i: Atmospheric Measurement Techniques. - : Copernicus GmbH. - 1867-1381 .- 1867-8548. ; 7:4, s. 983-1001
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Tidskriftsartikel (refereegranskat)abstract
- We describe a novel inlet that allows measurement of both gas and particle molecular composition when coupled to mass spectrometric, chromatographic, or optical sensors: the Filter Inlet for Gases and AEROsols (FIGAERO). The design goals for the FIGAERO are to allow unperturbed observation of ambient air while simultaneously analyzing gases and collecting particulate matter on a Teflon® (hereafter Teflon) filter via an entirely separate sampling port. The filter is analyzed periodically by the same sensor on hourly or faster timescales using temperature-programmed thermal desorption. We assess the performance of the FIGAERO by coupling it to a high-resolution time-of-flight chemical-ionization mass spectrometer (HRToF-CIMS) in laboratory chamber studies of α-pinene oxidation and field measurements at a boreal forest location. Low instrument backgrounds give detection limits of ppt or lower for compounds in the gas-phase and in the picogram m−3 range for particle phase compounds. The FIGAERO-HRToF-CIMS provides molecular information about both gases and particle composition on the 1 Hz and hourly timescales, respectively for hundreds of compounds. The FIGAERO thermal desorptions are highly reproducible (better than 10%), allowing a calibrated assessment of the effective volatility of desorbing compounds and the role of thermal decomposition during the desorption process. We show that the often multi-modal desorption thermograms arising from secondary organic aerosol (SOA) provide additional insights into molecular composition and/or particle morphology, and exhibit changes with changes in SOA formation or aging pathways.
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| 16. |
- McFiggans, Gordon, et al.
(författare)
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Secondary organic aerosol reduced by mixture of atmospheric vapours
- 2019
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 565:7741, s. 587-593
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Tidskriftsartikel (refereegranskat)abstract
- Secondary organic aerosol contributes to the atmospheric particle burden with implications for air quality and climate. Biogenic volatile organic compounds such as terpenoids emitted from plants are important secondary organic aerosol precursors with isoprene dominating the emissions of biogenic volatile organic compounds globally. However, the particle mass from isoprene oxidation is generally modest compared to that of other terpenoids. Here we show that isoprene, carbon monoxide and methane can each suppress the instantaneous mass and the overall mass yield derived from monoterpenes in mixtures of atmospheric vapours. We find that isoprene 'scavenges' hydroxyl radicals, preventing their reaction with monoterpenes, and the resulting isoprene peroxy radicals scavenge highly oxygenated monoterpene products. These effects reduce the yield of low-volatility products that would otherwise form secondary organic aerosol. Global model calculations indicate that oxidant and product scavenging can operate effectively in the real atmosphere. Thus highly reactive compounds (such as isoprene) that produce a modest amount of aerosol are not necessarily net producers of secondary organic particle mass and their oxidation in mixtures of atmospheric vapours can suppress both particle number and mass of secondary organic aerosol. We suggest that formation mechanisms of secondary organic aerosol in the atmosphere need to be considered more realistically, accounting for mechanistic interactions between the products of oxidizing precursor molecules (as is recognized to be necessary when modelling ozone production).
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