52 research outputs found
Spatial distribution of atmospheric PAHs and PCNs along a north-south Atlantic transect. Environ
source regions and air mass origin influence broad trends in oceanic air POPs concentrations, while diurnal cycling occurs in remote regions. 3 ). The highest PCN concentrations occurred in the European samples, but high values were also detected off the West African coast, and in the sample taken closest to South Africa. Data are presented for diurnal cycles taken in the remote South Atlantic. The day:night ratios of phenanthrene, 1-methylphenanthrene and fluoranthene were typically w1.5e2.5:1. The mechanism(s) causing this observation is/are not understood at present, but dynamic environmental process(es) is/are implicated
Aquatic Global Passive Sampling (AQUA-GAPS) Revisited – First Steps towards a Network of Networks for Organic Contaminants in the Aquatic Environment
Organic contaminants, in particular persistent organic pollutants (POPs), adversely affect water quality and aquatic food webs across the globe. As of now, there is no globally consistent information available on concentrations of dissolved POPs in water bodies. The advance of passive sampling techniques has made it possible to establish a global monitoring program for these compounds in the waters of the world, which we call the Aquatic Global Passive Sampling (AQUA-GAPS) network. A recent expert meeting discussed the background, motivations, and strategic approaches of AQUA-GAPS, and its implementation as a network of networks for monitoring organic contaminants (e.g., POPs and others contaminants of concern). Initially, AQUA-GAPS will demonstrate its operating principle via two proof-of-concept studies focused on the detection of legacy and emerging POPs in freshwater and coastal marine sites using both polyethylene and silicone passive samplers. AQUA-GAPS is set-up as a decentralized network, which is open to other participants from around the world to participate in deployments and to initiate new studies. In particular, participants are sought to initiate deployments and studies investigating the presence of legacy and emerging POPs in Africa, Central and South America
Ongoing Laboratory Performance Study on Chemical Analysis of Hydrophobic and Hydrophilic Compounds in Three Aquatic Passive Samplers
The quality of chemical analysis is an important aspect of passive sampling-based environmental assessments. The present study reports on a proficiency testing program for the chemical analysis of hydrophobic organic compounds in silicone and low-density polyethylene (LDPE) passive samplers and hydrophilic compounds in polar organic chemical integrative samplers. The median between-laboratory coefficients of variation (CVs) of hydrophobic compound concentrations in the polymer phase were 33% (silicone) and 38% (LDPE), similar to the CVs obtained in four earlier rounds of this program. The median CV over all rounds was 32%. Much higher variabilities were observed for hydrophilic compound concentrations in the sorbent: 50% for the untransformed data and a factor of 1.6 after log transformation. Limiting the data to the best performing laboratories did not result in less variability. Data quality for hydrophilic compounds was only weakly related to the use of structurally identical internal standards and was unrelated to the choice of extraction solvent and extraction time. Standard deviations of the aqueous concentration estimates for hydrophobic compound sampling by the best performing laboratories were 0.21 log units for silicone and 0.27 log units for LDPE (factors of 1.6 to 1.9). The implications are that proficiency testing programs may give more realistic estimates of uncertainties in chemical analysis than within-laboratory quality control programs and that these high uncertainties should be taken into account in environmental assessments
10Kin1day: a bottom-up neuroimaging initiative
We organized 10Kin1day, a pop-up scientific event with the goal to bring together neuroimaging groups from around the world to jointly analyze 10,000+ existing MRI connectivity datasets during a 3-day workshop. In this report, we describe the motivation and principles of 10Kin1day, together with a public release of 8,000+ MRI connectome maps of the human brain.The 10Kin1day workshop was generously sponsored by the Neuroscience and Cognition program Utrecht (NCU)
of the Utrecht University (https://www.uu.nl/en/research/neuroscience-and-cognition-utrecht), the ENIGMA consortium (http://enigma.ini.usc.edu), and personal grants: MvdH: NWOVIDI (452-16-015), MQ Fellowship; SB-C: the Wellcome Trust; Medical Research Council UK; NIHR CLAHRC for Cambridgeshire and Peterborough Foundation National Health Services Trust; Autism Research Trust; LB: New Investigator Award, Canadian Institutes of Health Research; Dara Cannon: Health Research Board (HRB), Ireland (grant code HRA-POR2013-324); SC: Research Grant Council (Hong Kong)-GRF 14101714; Eveline Crone: ERC-2010-StG-263234; UD: DFG,
grant FOR2107 DA1151/5-1, DA1151/5-2, SFB-TRR58, Project C09, IZKF, grant Dan3/012/17; SD: MRC-RFA-UFSP-01-2013 (Shared Roots MRC Flagship grant); TF: Marie Curie Programme, International Training Programme, r’Birth; DG: National Science Centre (UMO-2011/02/A/NZ5/00329); BG: National Science Centre (UMO-2011/02/A/NZ5/00329); JH: Western Sydney University Postgraduate Research Award; LH: Science Foundation Ireland, ERC; HH: Research Grant Council (Hong Kong)-GRF 14101714; LJ: Velux Stiftung, grant 369 & UZH University Research Priority Program Dynamics of Healthy Aging; AJ: DFG, grant FOR2107 JA 1890/7-1; KJ: National Science Centre (UMO-2013/09/N/HS6/02634); VK: The Russian Foundation for Basic Research (grant code 15-06-05758 A); TK: DFG, grant FOR2107 KI 588/14-1, DFG, grant FOR2107 KI 588/15-1; AK: DFG, grant FOR2107 KO 4291/4-1, DFG, grant FOR2107 KO 4291/3-1; IL: The Russian Foundation for Basic Research (grant code 15-06-05758 A); EL: Health and Medical Research Fund - 11121271; SiL: NHMRC-ARC Dementia
Fellowship 1110414, NHMRC Dementia Research Team Grant 1095127, NHMRC Project Grant 1062319; CL-J: 537-2011, 2014-849; AM: Wellcome Trust Strategic Award (104036/Z/14/Z), MRC Grant MC_PC_17209; CM: Heisenberg-Grant, German Research Foundation, DFG MO 2363/3-2; PM: Foundation for Science and Technology, Portugal - PDE/BDE/113601/2015; KN: National Science Centre (UMO-2011/02/A/NZ5/00329); PN: National Science Centre (UMO-2013/09/N/HS6/02634); JiP: NWO-Veni 451-10-007; PaR: PER and US would like to thank
the Schizophrenia Research Institute and the Chief-Investigators of the Australian Schizophrenia Research Bank V. Carr, U. Schall, R. Scott, A. Jablensky, B. Mowry, P. Michie, S. Catts, F. Henskens, and C. Pantelis; AS: National Science Centre (UMO-2011/02/A/NZ5/00329); SS: European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 707730; CS-M: Carlos III Health Institute (PI13/01958), Carlos III Health Institute (PI16/00889), Carlos III Health Institute (CPII16/00048); ES:
National Science Centre (UMO-2011/02/A/NZ5/00329); AT: The Russian Foundation for Basic Research (grant code 15-06-05758 A); DT-G: PI14/00918, PI14/00639; Leonardo Tozzi: Marie Curie Programme, International Training Programme, r’Birth; SV: IMPRS Neurocom stipend; TvE: National Center for Research Resources at the National Institutes of Health (grant numbers: NIH 1 U24 RR021992 (Function Biomedical Informatics Research Network), NIH 1 U24 RR025736-01 (Biomedical Informatics Research Network Coordinating Center; http://www.birncommunity.org) and the NIH Big Data to Knowledge (BD2K) award (U54 EB020403 to Paul
Thompson). NvH: NWO-VIDI (452-11-014); MW: National Science Centre (UMO-2011/02/A/NZ5/00329); Veronica O’Keane: Meath Foundation; AV and AW: CRC Obesity Mechanism (SFB 1052) Project A1 funded by DFG. The funding sources had no role in the study design, data collection, analysis, and interpretation of the data.
We further like to thank Joanna Goc, Veronica O’Keane, Devon Shook, and Leonardo Tozzi for their participation
and/or support of the 10K project. HCP data was provided by the Human Connectome Project, WU-Minn Consortium (Principal Investigators: David Van Essen and Kamil Ugurbil; 1U54MH091657) funded by the 16 NIH Institutes and Centers that support the NIH Blueprint for Neuroscience Research; and by the McDonnell Center for Systems Neuroscience at Washington University
On the Relationship Between the Optical Emission-Line and X-ray Luminosities in Seyfert 1 Galaxies
We have explored the relationship between the [O III] 5007 and the
2--10 keV luminosities for a sample of Broad- and Narrow-Line Seyfert 1
galaxies (BLSy1 and NLSy1, respectively). We find that both types of Seyferts
span the same range in luminosity and possess similar [O III]/X-ray ratios. The
NLSy1s are more luminous than BLSy1s, when normalized to their central black
hole masses, which is attributed to higher mass accretion rates. However, we
find no evidence for elevated [O III]/X-ray ratios in NLSy1s, which would have
been expected if they had excess EUV continuum emission compared to BLSy1s.
Also, other studies suggest that the gas in narrow-line regions (NLR) of NLSy1s
and NLSy1s span a similar range in ionization, contrary to what is expected if
those of the former are exposed to a stronger flux of EUV radiation. The
simplest interpretation is that, like BLSy1s, a large EUV bump is not present
in NLSy1s. However, we show that the [OIII]/X-ray ratio can be lowered as a
result of absorption of the ionizing continuum by gas close to the central
source, although there is no evidence that intrinsic line-of-sight absorption
is more common among NLSy1s, as would be expected if there were a larger amount
of circumnuclear gas. Other possible explanations include: 1) anisotropic
emission of the ionizing radiation, 2) higher gas densities in the NLR of
NLSy1s, resulting in lower average ionization, or 3) the presence of strong
winds in the the nuclei of NLSy1s which may drive off much of the gas in the
narrow-line region, resulting in lower cover fraction and weaker [O III]
emission.Comment: 18 pages, including 3 figures, 2 tables. Accepted for publication in
The Astrophysical Journa
10Kin1day: a bottom-up neuroimaging initiative
We organized 10Kin1day, a pop-up scientific event with the goal to bring together neuroimaging groups from around the world to jointly analyze 10,000+ existing MRI connectivity datasets during a 3-day workshop. In this report, we describe the motivation and principles of 10Kin1day, together with a public release of 8,000+ MRI connectome maps of the human brain
10Kin1day: A Bottom-Up Neuroimaging Initiative.
We organized 10Kin1day, a pop-up scientific event with the goal to bring together neuroimaging groups from around the world to jointly analyze 10,000+ existing MRI connectivity datasets during a 3-day workshop. In this report, we describe the motivation and principles of 10Kin1day, together with a public release of 8,000+ MRI connectome maps of the human brain
Exchange of solutes between sediment and water
Sediments act as sources and sinks for many compounds and elements. Trace metals and organic contaminants have a high particle affinity and can be absorbed or released by sediments; a large fraction of the elements that take part in the biological cycles (C, N, P) are mineralized in the sediment, and carbon dioxide, nitrate, and phosphate are released to the water column. Therefore, the study of fluxes between sediment and water column is important for the understanding of contaminant concentrations and eutrification levels. Solute fluxes can be studied in the laboratory bij confining a sediment sample and a volume of overlying water in a microcosm. Since the hydrodynamical conditions at the sediment water interface determine the solute exchange flux, the hydrodynamical calibration of microcosms is important. In this thesis a microcosm with calibrated hydrodynamics is evaluated. Measurements of oxygen fluxes to the sediment, and organix contaminant fluxes from the sediment are discussed. ...
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