TY - JOUR A1 - Comas-Bru, Laia A1 - Harrison, Sandy P. A1 - Werner, Martin A1 - Rehfeld, Kira A1 - Scroxton, Nick A1 - Veiga-Pires, Cristina A1 - Ahmad, Syed Masood A1 - Brahim, Yassine Ait A1 - Mozhdehi, Sahar Amirnezhad A1 - Arienzo, Monica A1 - Atsawawaranunt, Kamolphat A1 - Baker, Andy A1 - Braun, Kerstin A1 - Breitenbach, Sebastian Franz Martin A1 - Burstyn, Yuval A1 - Chawchai, Sakonvan A1 - Columbu, Andrea A1 - Deininger, Michael A1 - Demeny, Attila A1 - Dixon, Bronwyn A1 - Hatvani, Istvan Gabor A1 - Hu, Jun A1 - Kaushal, Nikita A1 - Kern, Zoltan A1 - Labuhn, Inga A1 - Lachniet, Matthew S. A1 - Lechleitner, Franziska A. A1 - Lorrey, Andrew A1 - Markowska, Monika A1 - Nehme, Carole A1 - Novello, Valdir F. A1 - Oster, Jessica A1 - Perez-Mejias, Carlos A1 - Pickering, Robyn A1 - Sekhon, Natasha A1 - Wang, Xianfeng A1 - Warken, Sophie A1 - Atkinson, Tim A1 - Ayalon, Avner A1 - Baldini, James A1 - Bar-Matthews, Miryam A1 - Bernal, Juan Pablo A1 - Boch, Ronny A1 - Borsato, Andrea A1 - Boyd, Meighan A1 - Brierley, Chris A1 - Cai, Yanjun A1 - Carolin, Stacy A1 - Cheng, Hai A1 - Constantin, Silviu A1 - Couchoud, Isabelle A1 - Cruz, Francisco A1 - Denniston, Rhawn A1 - Dragusin, Virgil A1 - Duan, Wuhui A1 - Ersek, Vasile A1 - Finne, Martin A1 - Fleitmann, Dominik A1 - Fohlmeister, Jens Bernd A1 - Frappier, Amy A1 - Genty, Dominique A1 - Holzkamper, Steffen A1 - Hopley, Philip A1 - Johnston, Vanessa A1 - Kathayat, Gayatri A1 - Keenan-Jones, Duncan A1 - Koltai, Gabriella A1 - Li, Ting-Yong A1 - Lone, Mahjoor Ahmad A1 - Luetscher, Marc A1 - Mattey, Dave A1 - Moreno, Ana A1 - Moseley, Gina A1 - Psomiadis, David A1 - Ruan, Jiaoyang A1 - Scholz, Denis A1 - Sha, Lijuan A1 - Smith, Andrew Christopher A1 - Strikis, Nicolas A1 - Treble, Pauline A1 - Unal-Imer, Ezgi A1 - Vaks, Anton A1 - Vansteenberge, Stef A1 - Voarintsoa, Ny Riavo G. A1 - Wong, Corinne A1 - Wortham, Barbara A1 - Wurtzel, Jennifer A1 - Zhang, Haiwei T1 - Evaluating model outputs using integrated global speleothem records of climate change since the last glacial JF - Climate of the past : an interactive open access journal of the European Geosciences Union N2 - Although quantitative isotope data from speleothems has been used to evaluate isotope-enabled model simulations, currently no consensus exists regarding the most appropriate methodology through which to achieve this. A number of modelling groups will be running isotope-enabled palaeoclimate simulations in the framework of the Coupled Model Intercomparison Project Phase 6, so it is timely to evaluate different approaches to using the speleothem data for data–model comparisons. Here, we illustrate this using 456 globally distributed speleothem δ18O records from an updated version of the Speleothem Isotopes Synthesis and Analysis (SISAL) database and palaeoclimate simulations generated using the ECHAM5-wiso isotope-enabled atmospheric circulation model. We show that the SISAL records reproduce the first-order spatial patterns of isotopic variability in the modern day, strongly supporting the application of this dataset for evaluating model-derived isotope variability into the past. However, the discontinuous nature of many speleothem records complicates the process of procuring large numbers of records if data–model comparisons are made using the traditional approach of comparing anomalies between a control period and a given palaeoclimate experiment. To circumvent this issue, we illustrate techniques through which the absolute isotope values during any time period could be used for model evaluation. Specifically, we show that speleothem isotope records allow an assessment of a model's ability to simulate spatial isotopic trends. Our analyses provide a protocol for using speleothem isotope data for model evaluation, including screening the observations to take into account the impact of speleothem mineralogy on δ18O values, the optimum period for the modern observational baseline and the selection of an appropriate time window for creating means of the isotope data for palaeo-time-slices. Y1 - 2019 U6 - https://doi.org/10.5194/cp-15-1557-2019 SN - 1814-9324 SN - 1814-9332 VL - 15 IS - 4 SP - 1557 EP - 1579 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Aarts, Alexander A. A1 - Anderson, Joanna E. A1 - Anderson, Christopher J. A1 - Attridge, Peter R. A1 - Attwood, Angela A1 - Axt, Jordan A1 - Babel, Molly A1 - Bahnik, Stepan A1 - Baranski, Erica A1 - Barnett-Cowan, Michael A1 - Bartmess, Elizabeth A1 - Beer, Jennifer A1 - Bell, Raoul A1 - Bentley, Heather A1 - Beyan, Leah A1 - Binion, Grace A1 - Borsboom, Denny A1 - Bosch, Annick A1 - Bosco, Frank A. A1 - Bowman, Sara D. A1 - Brandt, Mark J. A1 - Braswell, Erin A1 - Brohmer, Hilmar A1 - Brown, Benjamin T. A1 - Brown, Kristina A1 - Bruening, Jovita A1 - Calhoun-Sauls, Ann A1 - Callahan, Shannon P. A1 - Chagnon, Elizabeth A1 - Chandler, Jesse A1 - Chartier, Christopher R. A1 - Cheung, Felix A1 - Christopherson, Cody D. A1 - Cillessen, Linda A1 - Clay, Russ A1 - Cleary, Hayley A1 - Cloud, Mark D. A1 - Cohn, Michael A1 - Cohoon, Johanna A1 - Columbus, Simon A1 - Cordes, Andreas A1 - Costantini, Giulio A1 - Alvarez, Leslie D. Cramblet A1 - Cremata, Ed A1 - Crusius, Jan A1 - DeCoster, Jamie A1 - DeGaetano, Michelle A. A1 - Della Penna, Nicolas A1 - den Bezemer, Bobby A1 - Deserno, Marie K. A1 - Devitt, Olivia A1 - Dewitte, Laura A1 - Dobolyi, David G. A1 - Dodson, Geneva T. A1 - Donnellan, M. Brent A1 - Donohue, Ryan A1 - Dore, Rebecca A. A1 - Dorrough, Angela A1 - Dreber, Anna A1 - Dugas, Michelle A1 - Dunn, Elizabeth W. A1 - Easey, Kayleigh A1 - Eboigbe, Sylvia A1 - Eggleston, Casey A1 - Embley, Jo A1 - Epskamp, Sacha A1 - Errington, Timothy M. A1 - Estel, Vivien A1 - Farach, Frank J. A1 - Feather, Jenelle A1 - Fedor, Anna A1 - Fernandez-Castilla, Belen A1 - Fiedler, Susann A1 - Field, James G. A1 - Fitneva, Stanka A. A1 - Flagan, Taru A1 - Forest, Amanda L. A1 - Forsell, Eskil A1 - Foster, Joshua D. A1 - Frank, Michael C. A1 - Frazier, Rebecca S. A1 - Fuchs, Heather A1 - Gable, Philip A1 - Galak, Jeff A1 - Galliani, Elisa Maria A1 - Gampa, Anup A1 - Garcia, Sara A1 - Gazarian, Douglas A1 - Gilbert, Elizabeth A1 - Giner-Sorolla, Roger A1 - Glöckner, Andreas A1 - Göllner, Lars A1 - Goh, Jin X. A1 - Goldberg, Rebecca A1 - Goodbourn, Patrick T. A1 - Gordon-McKeon, Shauna A1 - Gorges, Bryan A1 - Gorges, Jessie A1 - Goss, Justin A1 - Graham, Jesse A1 - Grange, James A. A1 - Gray, Jeremy A1 - Hartgerink, Chris A1 - Hartshorne, Joshua A1 - Hasselman, Fred A1 - Hayes, Timothy A1 - Heikensten, Emma A1 - Henninger, Felix A1 - Hodsoll, John A1 - Holubar, Taylor A1 - Hoogendoorn, Gea A1 - Humphries, Denise J. A1 - Hung, Cathy O. -Y. A1 - Immelman, Nathali A1 - Irsik, Vanessa C. A1 - Jahn, Georg A1 - Jaekel, Frank A1 - Jekel, Marc A1 - Johannesson, Magnus A1 - Johnson, Larissa G. A1 - Johnson, David J. A1 - Johnson, Kate M. A1 - Johnston, William J. A1 - Jonas, Kai A1 - Joy-Gaba, Jennifer A. A1 - Kappes, Heather Barry A1 - Kelso, Kim A1 - Kidwell, Mallory C. A1 - Kim, Seung Kyung A1 - Kirkhart, Matthew A1 - Kleinberg, Bennett A1 - Knezevic, Goran A1 - Kolorz, Franziska Maria A1 - Kossakowski, Jolanda J. A1 - Krause, Robert Wilhelm A1 - Krijnen, Job A1 - Kuhlmann, Tim A1 - Kunkels, Yoram K. A1 - Kyc, Megan M. A1 - Lai, Calvin K. A1 - Laique, Aamir A1 - Lakens, Daniel A1 - Lane, Kristin A. A1 - Lassetter, Bethany A1 - Lazarevic, Ljiljana B. A1 - LeBel, Etienne P. A1 - Lee, Key Jung A1 - Lee, Minha A1 - Lemm, Kristi A1 - Levitan, Carmel A. A1 - Lewis, Melissa A1 - Lin, Lin A1 - Lin, Stephanie A1 - Lippold, Matthias A1 - Loureiro, Darren A1 - Luteijn, Ilse A1 - Mackinnon, Sean A1 - Mainard, Heather N. A1 - Marigold, Denise C. A1 - Martin, Daniel P. A1 - Martinez, Tylar A1 - Masicampo, E. J. A1 - Matacotta, Josh A1 - Mathur, Maya A1 - May, Michael A1 - Mechin, Nicole A1 - Mehta, Pranjal A1 - Meixner, Johannes A1 - Melinger, Alissa A1 - Miller, Jeremy K. A1 - Miller, Mallorie A1 - Moore, Katherine A1 - Möschl, Marcus A1 - Motyl, Matt A1 - Müller, Stephanie M. A1 - Munafo, Marcus A1 - Neijenhuijs, Koen I. A1 - Nervi, Taylor A1 - Nicolas, Gandalf A1 - Nilsonne, Gustav A1 - Nosek, Brian A. A1 - Nuijten, Michele B. A1 - Olsson, Catherine A1 - Osborne, Colleen A1 - Ostkamp, Lutz A1 - Pavel, Misha A1 - Penton-Voak, Ian S. A1 - Perna, Olivia A1 - Pernet, Cyril A1 - Perugini, Marco A1 - Pipitone, R. Nathan A1 - Pitts, Michael A1 - Plessow, Franziska A1 - Prenoveau, Jason M. A1 - Rahal, Rima-Maria A1 - Ratliff, Kate A. A1 - Reinhard, David A1 - Renkewitz, Frank A1 - Ricker, Ashley A. A1 - Rigney, Anastasia A1 - Rivers, Andrew M. A1 - Roebke, Mark A1 - Rutchick, Abraham M. A1 - Ryan, Robert S. A1 - Sahin, Onur A1 - Saide, Anondah A1 - Sandstrom, Gillian M. A1 - Santos, David A1 - Saxe, Rebecca A1 - Schlegelmilch, Rene A1 - Schmidt, Kathleen A1 - Scholz, Sabine A1 - Seibel, Larissa A1 - Selterman, Dylan Faulkner A1 - Shaki, Samuel A1 - Simpson, William B. A1 - Sinclair, H. Colleen A1 - Skorinko, Jeanine L. M. A1 - Slowik, Agnieszka A1 - Snyder, Joel S. A1 - Soderberg, Courtney A1 - Sonnleitner, Carina A1 - Spencer, Nick A1 - Spies, Jeffrey R. A1 - Steegen, Sara A1 - Stieger, Stefan A1 - Strohminger, Nina A1 - Sullivan, Gavin B. A1 - Talhelm, Thomas A1 - Tapia, Megan A1 - te Dorsthorst, Anniek A1 - Thomae, Manuela A1 - Thomas, Sarah L. A1 - Tio, Pia A1 - Traets, Frits A1 - Tsang, Steve A1 - Tuerlinckx, Francis A1 - Turchan, Paul A1 - Valasek, Milan A1 - Van Aert, Robbie A1 - van Assen, Marcel A1 - van Bork, Riet A1 - van de Ven, Mathijs A1 - van den Bergh, Don A1 - van der Hulst, Marije A1 - van Dooren, Roel A1 - van Doorn, Johnny A1 - van Renswoude, Daan R. A1 - van Rijn, Hedderik A1 - Vanpaemel, Wolf A1 - Echeverria, Alejandro Vasquez A1 - Vazquez, Melissa A1 - Velez, Natalia A1 - Vermue, Marieke A1 - Verschoor, Mark A1 - Vianello, Michelangelo A1 - Voracek, Martin A1 - Vuu, Gina A1 - Wagenmakers, Eric-Jan A1 - Weerdmeester, Joanneke A1 - Welsh, Ashlee A1 - Westgate, Erin C. A1 - Wissink, Joeri A1 - Wood, Michael A1 - Woods, Andy A1 - Wright, Emily A1 - Wu, Sining A1 - Zeelenberg, Marcel A1 - Zuni, Kellylynn T1 - Estimating the reproducibility of psychological science JF - Science N2 - Reproducibility is a defining feature of science, but the extent to which it characterizes current research is unknown. We conducted replications of 100 experimental and correlational studies published in three psychology journals using high-powered designs and original materials when available. Replication effects were half the magnitude of original effects, representing a substantial decline. Ninety-seven percent of original studies had statistically significant results. Thirty-six percent of replications had statistically significant results; 47% of original effect sizes were in the 95% confidence interval of the replication effect size; 39% of effects were subjectively rated to have replicated the original result; and if no bias in original results is assumed, combining original and replication results left 68% with statistically significant effects. Correlational tests suggest that replication success was better predicted by the strength of original evidence than by characteristics of the original and replication teams. Y1 - 2015 U6 - https://doi.org/10.1126/science.aac4716 SN - 1095-9203 SN - 0036-8075 VL - 349 IS - 6251 PB - American Assoc. for the Advancement of Science CY - Washington ER - TY - JOUR A1 - Atsawawaranunt, Kamolphat A1 - Comas-Bru, Laia A1 - Mozhdehi, Sahar Amirnezhad A1 - Deininger, Michael A1 - Harrison, Sandy P. A1 - Baker, Andy A1 - Boyd, Meighan A1 - Kaushal, Nikita A1 - Ahmad, Syed Masood A1 - Brahim, Yassine Ait A1 - Arienzo, Monica A1 - Bajo, Petra A1 - Braun, Kerstin A1 - Burstyn, Yuval A1 - Chawchai, Sakonvan A1 - Duan, Wuhui A1 - Hatvani, Istvan Gabor A1 - Hu, Jun A1 - Kern, Zoltan A1 - Labuhn, Inga A1 - Lachniet, Matthew A1 - Lechleitner, Franziska A. A1 - Lorrey, Andrew A1 - Perez-Mejias, Carlos A1 - Pickering, Robyn A1 - Scroxton, Nick A1 - Atkinson, Tim A1 - Ayalon, Avner A1 - Baldini, James A1 - Bar-Matthews, Miriam A1 - Pablo Bernal, Juan A1 - Breitenbach, Sebastian Franz Martin A1 - Boch, Ronny A1 - Borsato, Andrea A1 - Cai, Yanjun A1 - Carolin, Stacy A1 - Cheng, Hai A1 - Columbu, Andrea A1 - Couchoud, Isabelle A1 - Cruz, Francisco A1 - Demeny, Attila A1 - Dominguez-Villar, David A1 - Dragusin, Virgil A1 - Drysdale, Russell A1 - Ersek, Vasile A1 - Finne, Martin A1 - Fleitmann, Dominik A1 - Fohlmeister, Jens Bernd A1 - Frappier, Amy A1 - Genty, Dominique A1 - Holzkamper, Steffen A1 - Hopley, Philip A1 - Kathayat, Gayatri A1 - Keenan-Jones, Duncan A1 - Koltai, Gabriella A1 - Luetscher, Marc A1 - Li, Ting-Yong A1 - Lone, Mahjoor Ahmad A1 - Markowska, Monika A1 - Mattey, Dave A1 - McDermott, Frank A1 - Moreno, Ana A1 - Moseley, Gina A1 - Nehme, Carole A1 - Novello, Valdir F. A1 - Psomiadis, David A1 - Rehfeld, Kira A1 - Ruan, Jiaoyang A1 - Sekhon, Natasha A1 - Sha, Lijuan A1 - Sholz, Denis A1 - Shopov, Yavor A1 - Smith, Andrew A1 - Strikis, Nicolas A1 - Treble, Pauline A1 - Unal-Imer, Ezgi A1 - Vaks, Anton A1 - Vansteenberge, Stef A1 - Veiga-Pires, Cristina A1 - Voarintsoa, Ny Riavo A1 - Wang, Xianfeng A1 - Wong, Corinne A1 - Wortham, Barbara A1 - Wurtzel, Jennifer A1 - Zong, Baoyun T1 - The SISAL database BT - a global resource to document oxygen and carbon isotope records from speleothems JF - Earth System Science Data N2 - Stable isotope records from speleothems provide information on past climate changes, most particularly information that can be used to reconstruct past changes in precipitation and atmospheric circulation. These records are increasingly being used to provide "out-of-sample" evaluations of isotope-enabled climate models. SISAL (Speleothem Isotope Synthesis and Analysis) is an international working group of the Past Global Changes (PAGES) project. The working group aims to provide a comprehensive compilation of speleothem isotope records for climate reconstruction and model evaluation. The SISAL database contains data for individual speleothems, grouped by cave system. Stable isotopes of oxygen and carbon (delta O-18, delta C-13) measurements are referenced by distance from the top or bottom of the speleothem. Additional tables provide information on dating, including information on the dates used to construct the original age model and sufficient information to assess the quality of each data set and to erect a standardized chronology across different speleothems. The metadata table provides location information, information on the full range of measurements carried out on each speleothem and information on the cave system that is relevant to the interpretation of the records, as well as citations for both publications and archived data. Y1 - 2018 U6 - https://doi.org/10.5194/essd-10-1687-2018 SN - 1866-3508 SN - 1866-3516 VL - 10 IS - 3 SP - 1687 EP - 1713 PB - Copernicus CY - Göttingen ER - TY - BOOK A1 - Ahlefeld, Kristin A1 - Biemer, Anna-Lena A1 - Bredendiek, Florian A1 - Dunte, Stefan A1 - Fietze, Bianca A1 - Gamradt, Rebecca A1 - Jennek, Julia A1 - Nick, Gregor A1 - Schinagl, Martin A1 - Schmidt, Karsten T1 - Ein Kiez im Wandel der Zeit : Savignyplatz - von der Wende in neue Jahrtausend Y1 - 2008 PB - Univ. CY - Potsdam ER - TY - JOUR A1 - Yang, Jie A1 - Gühr, Markus A1 - Vecchione, Theodore A1 - Robinson, Matthew Scott A1 - Li, Renkai A1 - Hartmann, Nick A1 - Shen, Xiaozhe A1 - Coffee, Ryan A1 - Corbett, Jeff A1 - Fry, Alan A1 - Gaffney, Kelly A1 - Gorkhover, Tais A1 - Hast, Carsten A1 - Jobe, Keith A1 - Makasyuk, Igor A1 - Reid, Alexander A1 - Robinson, Joseph A1 - Vetter, Sharon A1 - Wang, Fenglin A1 - Weathersby, Stephen A1 - Yoneda, Charles A1 - Centurion, Martin A1 - Wang, Xijie T1 - Diffractive imaging of a rotational wavepacket in nitrogen molecules with femtosecond megaelectronvolt electron pulses JF - Nature Communications N2 - Imaging changes in molecular geometries on their natural femtosecond timescale with sub-Angstrom spatial precision is one of the critical challenges in the chemical sciences, as the nuclear geometry changes determine the molecular reactivity. For photoexcited molecules, the nuclear dynamics determine the photoenergy conversion path and efficiency. Here we report a gas-phase electron diffraction experiment using megaelectronvolt (MeV) electrons, where we captured the rotational wavepacket dynamics of nonadiabatically laser-aligned nitrogen molecules. We achieved a combination of 100 fs root-mean-squared temporal resolution and sub-Angstrom (0.76 angstrom) spatial resolution that makes it possible to resolve the position of the nuclei within the molecule. In addition, the diffraction patterns reveal the angular distribution of the molecules, which changes from prolate (aligned) to oblate (anti-aligned) in 300 fs. Our results demonstrate a significant and promising step towards making atomically resolved movies of molecular reactions. Y1 - 2016 U6 - https://doi.org/10.1038/ncomms11232 SN - 2041-1723 VL - 7 PB - Nature Publ. Group CY - London ER - TY - GEN A1 - Yang, Jie A1 - Guehr, Markus A1 - Vecchione, Theodore A1 - Robinson, Matthew Scott A1 - Li, Renkai A1 - Hartmann, Nick A1 - Shen, Xiaozhe A1 - Coffee, Ryan A1 - Corbett, Jeff A1 - Fry, Alan A1 - Gaffney, Kelly A1 - Gorkhover, Tais A1 - Hast, Carsten A1 - Jobe, Keith A1 - Makasyuk, Igor A1 - Reid, Alexander A1 - Robinson, Joseph A1 - Vetter, Sharon A1 - Wang, Fenglin A1 - Weathersby, Stephen A1 - Yoneda, Charles A1 - Wang, Xijie A1 - Centurion, Martin T1 - Femtosecond gas phase electron diffraction with MeV electrons N2 - We present results on ultrafast gas electron diffraction (UGED) experiments with femtosecond resolution using the MeV electron gun at SLAC National Accelerator Laboratory. UGED is a promising method to investigate molecular dynamics in the gas phase because electron pulses can probe the structure with a high spatial resolution. Until recently, however, it was not possible for UGED to reach the relevant timescale for the motion of the nuclei during a molecular reaction. Using MeV electron pulses has allowed us to overcome the main challenges in reaching femtosecond resolution, namely delivering short electron pulses on a gas target, overcoming the effect of velocity mismatch between pump laser pulses and the probe electron pulses, and maintaining a low timing jitter. At electron kinetic energies above 3 MeV, the velocity mismatch between laser and electron pulses becomes negligible. The relativistic electrons are also less susceptible to temporal broadening due to the Coulomb force. One of the challenges of diffraction with relativistic electrons is that the small de Broglie wavelength results in very small diffraction angles. In this paper we describe the new setup and its characterization, including capturing static diffraction patterns of molecules in the gas phase, finding time-zero with sub-picosecond accuracy and first time-resolved diffraction experiments. The new device can achieve a temporal resolution of 100 fs root-mean-square, and sub-angstrom spatial resolution. The collimation of the beam is sufficient to measure the diffraction pattern, and the transverse coherence is on the order of 2 nm. Currently, the temporal resolution is limited both by the pulse duration of the electron pulse on target and by the timing jitter, while the spatial resolution is limited by the average electron beam current and the signal-to-noise ratio of the detection system. We also discuss plans for improving both the temporal resolution and the spatial resolution. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 326 Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-394989 ER - TY - JOUR A1 - Yang, Jie A1 - Gühr, Markus A1 - Vecchione, Theodore A1 - Robinson, Matthew Scott A1 - Li, Renkai A1 - Hartmann, Nick A1 - Shen, Xiaozhe A1 - Coffee, Ryan A1 - Corbett, Jeff A1 - Fry, Alan A1 - Gaffney, Kelly A1 - Gorkhover, Tais A1 - Hast, Carsten A1 - Jobe, Keith A1 - Makasyuk, Igor A1 - Reid, Alexander A1 - Robinson, Joseph A1 - Vetter, Sharon A1 - Wang, Fenglin A1 - Weathersby, Stephen A1 - Yoneda, Charles A1 - Wang, Xijie A1 - Centurion, Martin T1 - Femtosecond gas phase electron diffraction with MeV electrons JF - Faraday discussions N2 - We present results on ultrafast gas electron diffraction (UGED) experiments with femtosecond resolution using the MeV electron gun at SLAC National Accelerator Laboratory. UGED is a promising method to investigate molecular dynamics in the gas phase because electron pulses can probe the structure with a high spatial resolution. Until recently, however, it was not possible for UGED to reach the relevant timescale for the motion of the nuclei during a molecular reaction. Using MeV electron pulses has allowed us to overcome the main challenges in reaching femtosecond resolution, namely delivering short electron pulses on a gas target, overcoming the effect of velocity mismatch between pump laser pulses and the probe electron pulses, and maintaining a low timing jitter. At electron kinetic energies above 3 MeV, the velocity mismatch between laser and electron pulses becomes negligible. The relativistic electrons are also less susceptible to temporal broadening due to the Coulomb force. One of the challenges of diffraction with relativistic electrons is that the small de Broglie wavelength results in very small diffraction angles. In this paper we describe the new setup and its characterization, including capturing static diffraction patterns of molecules in the gas phase, finding time-zero with sub-picosecond accuracy and first time-resolved diffraction experiments. The new device can achieve a temporal resolution of 100 fs root-mean-square, and sub-angstrom spatial resolution. The collimation of the beam is sufficient to measure the diffraction pattern, and the transverse coherence is on the order of 2 nm. Currently, the temporal resolution is limited both by the pulse duration of the electron pulse on target and by the timing jitter, while the spatial resolution is limited by the average electron beam current and the signal-to-noise ratio of the detection system. We also discuss plans for improving both the temporal resolution and the spatial resolution. Y1 - 2016 U6 - https://doi.org/10.1039/c6fd00071a SN - 1359-6640 SN - 1364-5498 VL - 194 SP - 563 EP - 581 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Yang, Jie A1 - Guehr, Markus A1 - Shen, Xiaozhe A1 - Li, Renkai A1 - Vecchione, Theodore A1 - Coffee, Ryan A1 - Corbett, Jeff A1 - Fry, Alan A1 - Hartmann, Nick A1 - Hast, Carsten A1 - Hegazy, Kareem A1 - Jobe, Keith A1 - Makasyuk, Igor A1 - Robinson, Joseph A1 - Robinson, Matthew Scott A1 - Vetter, Sharon A1 - Weathersby, Stephen A1 - Yoneda, Charles A1 - Wang, Xijie A1 - Centurion, Martin T1 - Diffractive Imaging of Coherent Nuclear Motion in Isolated Molecules JF - Physical review letters N2 - Observing the motion of the nuclear wave packets during a molecular reaction, in both space and time, is crucial for understanding and controlling the outcome of photoinduced chemical reactions. We have imaged the motion of a vibrational wave packet in isolated iodine molecules using ultrafast electron diffraction with relativistic electrons. The time-varying interatomic distance was measured with a precision 0.07 angstrom and temporal resolution of 230 fs full width at half maximum. The method is not only sensitive to the position but also the shape of the nuclear wave packet. Y1 - 2016 U6 - https://doi.org/10.1103/PhysRevLett.117.153002 SN - 0031-9007 SN - 1079-7114 VL - 117 PB - American Physical Society CY - College Park ER - TY - JOUR A1 - Graae, Bente J. A1 - De Frenne, Pieter A1 - Kolb, Annette A1 - Brunet, Jorg A1 - Chabrerie, Olivier A1 - Verheyen, Kris A1 - Pepin, Nick A1 - Heinken, Thilo A1 - Zobel, Martin A1 - Shevtsova, Anna A1 - Nijs, Ivan A1 - Milbau, Ann T1 - On the use of weather data in ecological studies along altitudinal and latitudinal gradients JF - Oikos N2 - Global warming has created a need for studies along climatic gradients to assess the effects of temperature on ecological processes. Altitudinal and latitudinal gradients are often used as such, usually in combination with air temperature data from the closest weather station recorded at 1.52 m above the ground. However, many ecological processes occur in, at, or right above the soil surface. To evaluate how representative the commonly used weather station data are for the microclimate relevant for soil surface biota, we compared weather station temperatures for an altitudinal (500900 m a.s.l.) and a latitudinal gradient (4968 degrees N) with data obtained by temperature sensors placed right below the soil surface at five sites along these gradients. The mean annual temperatures obtained from weather stations and adjusted using a lapse rate of -5.5 degrees C km-1 were between 3.8 degrees C lower and 1.6 degrees C higher than those recorded by the temperature sensors at the soil surface, depending on the position along the gradients. The monthly mean temperatures were up to 10 degrees C warmer or 5 degrees C colder at the soil surface. The within-site variation in accumulated temperature was as high as would be expected from a 300 m change in altitude or from a 4 degrees change in latitude or a climate change scenario corresponding to warming of 1.63.8 degrees C. Thus, these differences introduced by the decoupling are significant from a climate change perspective, and the results demonstrate the need for incorporating microclimatic variation when conducting studies along altitudinal or latitudinal gradients. We emphasize the need for using relevant temperature data in climate impact studies and further call for more studies describing the soil surface microclimate, which is crucial for much of the biota. Y1 - 2012 U6 - https://doi.org/10.1111/j.1600-0706.2011.19694.x SN - 0030-1299 VL - 121 IS - 1 SP - 3 EP - 19 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Süsser, Diana A1 - Martin, Nick A1 - Stavrakas, Vassilis A1 - Gaschnig, Hannes A1 - Talens-Peiró, Laura A1 - Flamos, Alexandros A1 - Madrid-López, Cristina A1 - Lilliestam, Johan T1 - Why energy models should integrate social and environmental factors BT - assessing user needs, omission impacts, and real-word accuracy in the European Union JF - Energy research & social science N2 - Energy models are used to inform and support decisions within the transition to climate neutrality. In recent years, such models have been criticised for being overly techno-centred and ignoring environmental and social factors of the energy transition. Here, we explore and illustrate the impact of ignoring such factors by comparing model results to model user needs and real-world observations. We firstly identify concrete user needs for better representation of environmental and social factors in energy modelling via interviews, a survey and a workshop. Secondly, we explore and illustrate the effects of omitting non-techno-economic factors in modelling by contrasting policy-targeted scenarios with reality in four EU case study examples. We show that by neglecting environmental and social factors, models risk generating overly optimistic and potentially misleading results, for example by suggesting transition speeds far exceeding any speeds observed, or pathways facing hard-to-overcome resource constraints. As such, modelled energy transition pathways that ignore such factors may be neither desirable nor feasible from an environmental and social perspective, and scenarios may be irrelevant in practice. Finally, we discuss a sample of recent energy modelling innovations and call for continued and increased efforts for improved approaches that better represent environmental and social factors in energy modelling and increase the relevance of energy models for informing policymaking. KW - energy modelling KW - energy planning KW - energy policy KW - ecological crisis KW - social acceptance KW - environmental impacts Y1 - 2022 U6 - https://doi.org/10.1016/j.erss.2022.102775 SN - 2214-6296 VL - 92 SP - 102775 EP - 102775 PB - Elsevier CY - Amsterdam ER -