Giles Smith, Andrew Robson, Gabriele Marcotti, David Adams, Matthew Syed, DJM, Yvonne Lowe, Neelam Verjee, George Caulkin and Oliver Kay, Nathan Williams, Andrew Fifield, Alan M. Pardoe, Adam Sherwin Media Reporter, Gary Duncan, Robert Gutfreund-Walmsley, Peter Lansley, David Wilson, Robert Thicknesse, Paul Hoggart, Mark Souster, David Rhys Jones, Richard Hobson, James Wilson (Senior News Editor), Terry Hope, Ian Winrow, Philip Howard, Clint Esston, Christine Seib, David Chater, Jean-Marie Okwo-Bele, Michael Binyon, Joanna Bale, James Ducker, Penny Wark, James Hider and Richard Beeston, Clive Davis, Alexandra Frean Social Affairs Correspondent, Richard Hobson One-Day Cricket Correspondent, Anthony Browne and Robert Thomson, Gabrielle Starkey, Carl Mortished, Alan Edwards, Rondy Cohen, Sam Marlowe, C. P. Edwards, Sam Lister, Joe Joseph, Valerie Elliott Countryside Editor, Gabriel Rozenberg and Peter Klinger, Anthony Browne, Tom Dary, Tom Bawden, Ruth Gledhill, Dominic Walsh, Debra Craine, Ronald Forrest, Wells, Somarset, Kelvin Langmead, Jill Dupleix, Toby Moore, Jonathan Gornall, Alan Hamilton, Stephen Farrell, Jan Wise, James Delingpole, Ann Jameson, Phil Gordon, Matthew Carragher, Keith Pike, David Hands, Ron Lewis, Diana Norman, Liz Chong, Bronwen Maddox Foreign Editor's Briefing, Greg Hurst, Angela Jameson, Simon Tait, Bernard Crick, Tom Kennedy, Russel Duncan, Russell Kempson, Tony Halpin Education Editor, Barbara Rowlands, Oliver Kay, Mark Atherton, John Westerby, Neil Harman, Rick Broadbent, Russell Jenkins and Laura Mannering, Mark Henderson Science Correspondent, John Barnwell, Alan Lee Racing Journalist, Simon de Bruxelles, Will Jenson, Rob Wright, Alice Olins, David Lister and David Sanderson, Neil Harman Tennis Correspondent, Raymond Keene, Mary Kenny, David Powel Athletics Correspondent, Adam Sage, Matthew Pryor, Jesper Christiansen, Kaveh Solhekol, Chris Campling, Colin Parker, Richard Owen, Lee Miller, Peter Dixon, Gabriel Rozenberg Economics Reporter, Jeffrey Titford, David Hands Rugby Correspondent, Tony Cascarino, Tom Dart, Paul Simons, James Cowling, Elizabeth Price, John Fitzgerald, Dalkeith, John Allison, William Rees-Mogg, Nick Szczepanik, James Hider and Ali al-Hamdani, Richard Beeston and Roland Watson, Philip Webster Political Editor, Glyn Edwards, Claire Turvey, Tim Hames, Ian Johns, Ashling O'connor, Tessa Thomas, Anjana Ahuja, C. Kinch, George Caulkin, L. L. Blake, Ingrid Mansell, Michael Austin, Alan Lee, Caitlin Moran, Walter Gammie, Donald Spiers, Philip Venning, Richard Beeston, Brian Glanville, Ben Webster, Carl Singer, David Sinclair, Lewis Stuart, Jason Mellor, Noel Whelan, Chris Ayres, Christopher Irvine, Carl Mortished International Business Editor, Nicola Woolcock and Ingrid Mansell, Ashling O'Connor, Stephen Farrell and Ian Mackinnon, Aki Riihilahti, John Chambers, Dr Thomas Stuttaford, Stephen Dalton, David Powell, Bill Edgar, Alyson Rudd, Julian Bennett, Michael Evans, Amir Taheri, Caryl Patterson, Robert Buckland, Edward Gorman Sailing Correspondent, Peter Klinger, Lisa Verrico, Phyllis Ward,
The Times Death-link drug to be withdrawn Ukraine's EU bid Tax challenge The Game Vaughan's victory Single issue 'The last British politician to exploit ...
2005 - Gale Group | TDA
Martin Boesgaard, Mette Vesterager, Thomas B. Pedersen, Jesper Christiansen, Ove Scavenius,
We present a new stream cipher, Rabbit, based on iterating a set of coupled non-linear functions. Rabbit is characterized by a high performance in software with a measured encryption/decryption speed of 3.7 clock cycles per byte on a Pentium III processor. We have performed detailed security analysis, in particular, correlation analysis and algebraic investigations. The cryptanalysis of Rabbit did not reveal an attack better than exhaustive key search.
Tópico(s): Coding theory and cryptography
2003 - Springer Science+Business Media | Lecture notes in computer science
We consider QCD_3 with an odd number of flavors in the mesoscopic scaling region where the field theory finite-volume partition function is equivalent to a random matrix theory partition function. We argue that the theory is parity invariant at the classical level if an odd number of masses are zero. By introducing so-called pseudo-orthogonal polynomials we are able to relate the kernel to the kernel of the chiral unitary ensemble in the sector of topological charge $\nu={1/2}$. We prove universality ...
Tópico(s): Theoretical and Computational Physics
1999 - Elsevier BV | Nuclear Physics B
Sarah Elise Sapper, Christian Juncher Jørgensen, Moritz Schroll, Frank Keppler, Jesper Riis Christiansen,
Subglacial meltwater of land-terminating glaciers in Greenland and Iceland are sources of methane (CH4) to the atmosphere, but sparse empirical data exist about the spatial distribution of subglacial CH4 production and emission from glaciers in other regions of the world. This study presents the first measurements of CH4 emissions from the subglacial meltwater of three outlet glaciers of the St. Elias Mountains in Yukon, Canada. Dissolved CH4 concentrations were highly elevated at 45, 135, and 250 ...
Tópico(s): Climate change and permafrost
2023 - Institute of Arctic and Alpine Research | Arctic Antarctic and Alpine Research
Jesper Riis Christiansen, Thomas Röckmann, María Elena Popa, Célia Sapart, Christian Juncher Jørgensen,
Abstract Direct gaseous emissions of methane (CH 4 ) and carbon dioxide (CO 2 ) from the subglacial environment under Greenland Ice Sheet (GrIS) were only recently discovered and it is yet to be determined how important it is for the panarctic carbon budget. We measured in situ net gaseous emissions of subglacial CH 4 and CO 2 , dissolved concentrations and isotopic composition of gases ( 13 C and 2 H) at the onset, near maximum, and at the end of the melt season in 2018 and 2019. We found a tight relation ...
Tópico(s): Atmospheric and Environmental Gas Dynamics
2021 - Wiley | Journal of Geophysical Research Biogeosciences
Timothy J. Clough, Philippe Rochette, S. Thomas, Mari Pihlatie, Jesper Riis Christiansen, R. E. Thorman,
Abstract Terrestrial ecosystems, both natural ecosystems and agroecosystems, generate greenhouse gases (GHGs). The chamber method is the most common method to quantify GHG fluxes from soil–plant systems and to better understand factors affecting their generation and mitigation. The objective of this study was to review and synthesize literature on chamber designs (non‐flow‐through, non‐steady‐state chamber) and associated factors that affect GHG nitrous oxide (N 2 O) flux measurement when using chamber ...
Tópico(s): Groundwater flow and contamination studies
2020 - Wiley | Journal of Environmental Quality
Jessica Carlsson, Jesper Riis Christiansen, Sabina Davidsson, Francesca Giunchi, Michelangelo Fiorentino, Pernilla Sundqvist,
Renal cell carcinoma (RCC) is the most commonly diagnosed renal tumor, consisting of ~3% of all malignancies worldwide. The prognosis of RCC can vary widely, and detecting patients at risk of recurrence at an early stage of disease may improve patient outcome. The factors presently used in a clinical setting cannot reliably predict the natural history of the disease. Therefore, there is a requirement to identify novel biomarkers that can aid in predicting patient outcome. Previous studies have indicated ...
Tópico(s): Extracellular vesicles in disease
2019 - Spandidos Publishing | Oncology Letters
Jyrki Jauhiainen, Jukka Alm, Brynhildur Bjarnadóttir, Ingeborg Callesen, Jesper Riis Christiansen, Nicholas Clarke, Lise Dalsgaard, Hongxing He, Sabine Jordan, Vaiva Kazanavičiūtė, Leif Klemedtsson, Ari Laurén, Andis Lazdiņš, Aleksi Lehtonen, Annalea Lohila, Ainārs Lupiķis, Ülo Mander, Kari Minkkinen, Åsa Kasimir, Mats Olsson, Paavo Ojanen, Hlynur Óskarsson, Bjarni D. Sigurðsson, Gunnhild Søgaard, Kaido Soosaar, Lars Vesterdal, Raija Laiho,
Abstract. Drained organic forest soils in boreal and temperate climate zones are believed to be significant sources of the greenhouse gases (GHGs) carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O), but the annual fluxes are still highly uncertain. Drained organic soils exemplify systems where many studies are still carried out with relatively small resources, several methodologies and manually operated systems, which further involve different options for the detailed design of the measurement ...
Tópico(s): Climate change and permafrost
2019 - Copernicus Publications | Biogeosciences
Jüergen Kreyling, Andreas Schweiger, Michael Bahn, Phil Ineson, Mirco Migliavacca, Thibaut Morel‐Journel, Jesper Riis Christiansen, Nicolas Schtickzelle, Klaus Steenberg Larsen,
A fundamental challenge in experimental ecology is to capture nonlinearities of ecological responses to interacting environmental drivers. Here, we demonstrate that gradient designs outperform replicated designs for detecting and quantifying nonlinear responses. We report the results of (1) multiple computer simulations and (2) two purpose-designed empirical experiments. The findings consistently revealed that unreplicated sampling at a maximum number of sampling locations maximised prediction success ( ...
Tópico(s): Rangeland and Wildlife Management
2018 - Wiley | Ecology Letters
Jesper Riis Christiansen, Christian Juncher Jørgensen,
During a 2016 field expedition to the West Greenland Ice Sheet, a striking observation of significantly elevated CH4 concentrations of up to 15 times the background atmospheric concentration were measured directly in the air expelled with meltwater at a subglacial discharge point from the Greenland Ice Sheet. The range of hourly subglacial CH4 flux rate through the discharge point was estimated to be 3.1 to 134 g CH4 hr-1. These measurements are the first observations of direct emissions of CH4 ...
Tópico(s): Atmospheric and Environmental Gas Dynamics
2018 - Nature Portfolio | Scientific Reports
Jesper Riis Christiansen, David J. Levy‐Booth, Cindy E. Prescott, S. J. Grayston,
In a changing climate, understanding how soil hydrology impacts greenhouse gas dynamics will be important for the future management of the soils in the forests on the Canadian Pacific west coast. In a laboratory study, the impact of soil hydrology on potential net methane (CH 4 ) exchange rates and the abundance of methanotrophs (CH 4 oxidation) and methanogens (CH 4 production) in upland and water-saturated wet soils were investigated. CH 4 oxidation and production rates were highest in the wet soils, ...
Tópico(s): Methane Hydrates and Related Phenomena
2017 - NRC Research Press | Canadian Journal of Forest Research
Torben O. Sonnenborg, Jesper Riis Christiansen, Bo Pang, Antoine Bruge, Simon Stisen, Per Gundersen,
Groundwater depletion occurs at a global scale but requires regional strategies for sustainable management of freshwater resources. In Denmark the groundwater quantity and quality is under pressure, and forested areas are considered to protect groundwater reservoirs. However, little is known on how afforestation or forest conversion impacts the water resource at the catchment scale. We hypothesize that the groundwater formation and streamflow is increased when water consuming conifers are replaced ...
Tópico(s): Groundwater flow and contamination studies
2017 - Elsevier BV | Agricultural and Forest Meteorology
Jesper Riis Christiansen, David J. Levy‐Booth, Cindy E. Prescott, S. J. Grayston,
Tópico(s): Soil Carbon and Nitrogen Dynamics
2016 - Springer Science+Business Media | Ecosystems
Jesper Riis Christiansen, Josh Outhwaite, Sean Smukler,
A laboratory and field experiment compared fluxes of CO2, CH4 and N2O measured with cavity ring-down spectroscopy (CRDS) and gas chromatography (GC). The comparison between CRDS and GC showed that average CO2 fluxes were significantly higher for CRDS in both the laboratory and field, but the same experimental treatments effects were detected for both techniques. Compared to CRDS, the GC technique was severely limited in detecting CH4 fluxes in both the laboratory and field. Thus, only 16% of measured ...
Tópico(s): CO2 Sequestration and Geologic Interactions
2015 - Elsevier BV | Agricultural and Forest Meteorology
Jesper Riis Christiansen, Alejandro Jose Barrera Romero, Niels O. G. Jørgensen, Mikkel A. Glaring, Christian Juncher Jørgensen, Louise Kristine Berg, Bo Elberling,
Arctic soils are known to be important methane (CH4) consumers and sources. This study integrates in situ fluxes of CH4 between upland and wetland soils with potential rates of CH4 oxidation and production as well as abundance and diversity of the methanotrophs and methanogens measured with pyrosequencing of 16S DNA and rRNA fragments in soil and permafrost layers. Here, the spatial patterns of in situ CH4 fluxes for a 2,000 years old Arctic landscape in West Greenland reveal similar CH4 uptake rates (− ...
Tópico(s): Peatlands and Wetlands Ecology
2014 - Springer Science+Business Media | Biogeochemistry
Téresa G. Bárcena, Ludovica D’Imperio, Per Gundersen, Lars Vesterdal, Anders Priemé, Jesper Riis Christiansen,
We investigated CH4 oxidation in afforested soils over a 200-year chronosequence in Denmark including different tree species (Norway spruce, oak and larch) and ages. Samples of the top mineral soil (0–5 cm and 5–15 cm depth) were incubated and analyzed for the abundance of the soil methane-oxidizing bacteria (MOB) and ammonia-oxidizing bacteria (AOB) and archaea (AOA) based on quantitative PCR (qPCR) on pmoA and amoA genes. Our study showed that CH4 oxidation rates and the abundance of MOB increased simultaneously ...
Tópico(s): Peatlands and Wetlands Ecology
2014 - Elsevier BV | Applied Soil Ecology
Mari Pihlatie, Jesper Riis Christiansen, Hermanni Aaltonen, Janne F. J. Korhonen, Annika Nordbo, Terhi Rasilo, Giuseppe Benanti, Michael Giebels, Mohamed Helmy, Jatta Sheehy, Stephanie Jones, Radosław Juszczak, Roland Klefoth, Raquel Lobo‐do‐Vale, Ana Paula Rosa, Peter Schreiber, D. Serça, Sara Vicca, Benjamin Wolf, Jukka Pumpanen,
The static chamber method (non-flow-through-non-steady-state chambers) is the most common method to measure fluxes of methane (CH4) from soils. Laboratory comparisons to quantify errors resulting from chamber design, operation and flux calculation methods are rare. We tested fifteen chambers against four flux levels (FL) ranging from 200 to 2300 μg CH4 m−2 h−1. The measurements were conducted on a calibration tank using three quartz sand types with soil porosities of 53% (dry fine sand, S1), 47% (dry ...
Tópico(s): Groundwater flow and contamination studies
2013 - Elsevier BV | Agricultural and Forest Meteorology
Jesper Riis Christiansen, Per Gundersen, Preben Frederiksen, Lars Vesterdal,
Recent research has shown that wet or hydromorphic soils in forests are hotspots for greenhouse gas (GHG) emission of methane (CH4) and nitrous oxide (N2O), and that emission of these gases may offset the mitigation potential from carbon (C) sequestration. However, quantitative evidence at the forest scale is limited. We investigated the role of hydromorphic soils for N2O and CH4 fluxes at the forest district level (Barritskov, 348 ha) by mapping the distribution of upland and hydromorphic soils, measuring ...
Tópico(s): Soil Carbon and Nitrogen Dynamics
2012 - Elsevier BV | Forest Ecology and Management
Per Gundersen, Jesper Riis Christiansen, Giorgio Alberti, Nicolas Brüggemann, Simona Castaldi, Rainer Gasché, Barbara Kitzler, Leif Klemedtsson, Raquel Lobo‐do‐Vale, Filip Moldan, Tobias Rütting, Patrick Schleppi, Per Weslien, Sophie Zechmeister‐Boltenstern,
Abstract. Forests in Europe are changing due to interactions between climate change, nitrogen (N) deposition and new forest management practices. The concurrent impact on the forest greenhouse gas (GHG) balance is at present difficult to predict due to a lack of knowledge on controlling factors of GHG fluxes and response to changes in these factors. To improve the mechanistic understanding of the ongoing changes, we studied the response of soil–atmosphere exchange of nitrous oxide (N2O) and methane ( ...
Tópico(s): Atmospheric and Environmental Gas Dynamics
2012 - Copernicus Publications | Biogeosciences
Ingeborg Callesen, Lars Ola Nilsson, Inger Kappel Schmidt, Lars Vesterdal, Per Ambus, Jesper Riis Christiansen, Peter Högberg, Per Gundersen,
Tópico(s): Soil and Water Nutrient Dynamics
2012 - Springer Science+Business Media | Plant and Soil
Jesper Riis Christiansen, Janne F. J. Korhonen, Radosław Juszczak, Michael Giebels, Mari Pihlatie,
Tópico(s): Groundwater flow and contamination studies
2011 - Springer Science+Business Media | Plant and Soil
Lars Vesterdal, Bo Elberling, Jesper Riis Christiansen, Ingeborg Callesen, Inger Kappel Schmidt,
The knowledge of tree species effects on soil organic carbon (C) turnover based on rigorous experimental designs is limited for common European deciduous tree species. We assessed soil respiration, and rates of C turnover in six tree species in a more than 30-year-old common garden experiment replicated at six sites in Denmark. The studied tree species were the broadleaves beech (Fagus sylvatica L.), pedunculate oak (Quercus robur L.), lime (Tilia cordata L.), sycamore maple (Acer pseudoplatanus L.) ...
Tópico(s): Fire effects on ecosystems
2011 - Elsevier BV | Forest Ecology and Management
Jesper Riis Christiansen, Per Gundersen,
Abstract. Afforestation of former agricultural land is a means to mitigate anthropogenic greenhouse gas emissions. The objectives of this study were (1) to assess the effect of oak (Quercus robur) and Norway spruce (Picea abies [L.] Karst.) stands of different stand ages (13–17 and 40 years after afforestation, respectively) on N2O and CH4 exchange from the soil under these species and (2) identify the environmental factors responsible for the differences in gas exchange between tree species of different ...
Tópico(s): Fire effects on ecosystems
2011 - Copernicus Publications | Biogeosciences
Jesper Riis Christiansen, Lars Vesterdal, Per Gundersen,
Tópico(s): Soil Carbon and Nitrogen Dynamics
2010 - Springer Science+Business Media | Biogeochemistry
Jesper Riis Christiansen, Lars Vesterdal, Ingeborg Callesen, Bo Elberling, Inger Kappel Schmidt, Per Gundersen,
Abstract Water and nutrient fluxes for single stands of different tree species have been reported in numerous studies, but comparative studies of nutrient and hydrological budgets of common European deciduous tree species are rare. Annual fluxes of water and inorganic nitrogen (N) were established in a 30‐year‐old common garden design with stands of common ash ( Fraxinus excelsior ), European beech ( Fagus sylvatica L.), pedunculate oak ( Quercus robur ), small‐leaved lime ( Tilia cordata Mill.), sycamore maple ( ...
Tópico(s): Forest ecology and management
2009 - Wiley | Global Change Biology
Per Gundersen, Lisbeth Sevel, Jesper Riis Christiansen, Lars Vesterdal, Karin Hansen, Annemarie Bastrup‐Birk,
The area of broadleaved forests is projected to increase in Denmark as well as in the rest of Europe. However, studies of the N leaching response to elevated N deposition have focused on coniferous stands and considerable uncertainty still remains on whether broadleaved and coniferous forests respond differently to elevated N. We studied N input–output relations for eight stands intensively monitored during 2002–2005 and literature data for 37 additional stands which together formed a comprehensive ...
Tópico(s): Peatlands and Wetlands Ecology
2009 - Elsevier BV | Forest Ecology and Management
Yunting Fang, Per Gundersen, Wei Zhang, Guoyi Zhou, Jesper Riis Christiansen, Jiangming Mo, Shaofeng Dong, Tao Zhang,
Tópico(s): Soil Carbon and Nitrogen Dynamics
2008 - Springer Science+Business Media | Plant and Soil
Jesper Riis Christiansen, Bo Elberling, Per‐Erik Jansson,
Two contrasting forest ecosystems located in close proximity to each other were selected for evaluating the importance of tree species and afforestation in relation to the water balance and the quality of the water leaving the forest root zone. Measurements included soil water content and the collection of precipitation, canopy throughfall, stem flow and soil solution on a weekly basis during 15 months (1999–2000). Soil solutions were extracted using suction probes installed at all major horizons ...
Tópico(s): Hydrology and Watershed Management Studies
2006 - Elsevier BV | Forest Ecology and Management
Jesper Skovdal Christiansen, Mette Thorsen, Thomas Clausen, Søren Hansen, Jens Christian Refsgaard,
Macropores play a significant role as a preferential flow mechanism in connection with pesticide leaching to shallow groundwater in clayey and loamy soils. A macropore description based on some of the same principles as those of the MACRO code has been added to the coupled MIKE SHE/Daisy code, enabling a physically based simulation of macropore processes in a spatially distributed manner throughout an entire catchment. Simulation results from a small catchment in Denmark suggest that although the ...
Tópico(s): Landfill Environmental Impact Studies
2004 - Elsevier BV | Journal of Hydrology
Eva Boegh, Mette Thorsen, Michael Butts, Søren Hansen, Jesper Skovdal Christiansen, Per Abrahamsen, Charlotte Bay Hasager, N.O. Jensen, Peter van der Keur, Jens Christian Refsgaard, K. Schelde, H. Soegaard, A. Thomsen,
Distributed information on land use and vegetation parameters is important for the correct predictions of evapotranspiration rate and soil water balance while, in turn, the growth and function of vegetation are also highly dependent on the soil water availability. In this study, the relationship between the soil water balance and the vegetation growth is represented by coupling a hydrological model (MIKE SHE) and a vegetation-SVAT model (Daisy) which simulates the interactions between soil, vegetation ...
Tópico(s): Hydrology and Watershed Management Studies
2004 - Elsevier BV | Journal of Hydrology