A13E:
VOC Chemistry and OH Reactivity: Known Unknowns and Unknown Unknowns III Posters


Session ID#: 8720

Session Description:
The tropospheric reactions of volatile organic compounds (VOCs), particularly biogenic VOCs, play a fundamental role in governing air quality and climate, yet remain poorly understood. Multi-faceted research is being conducted to elucidate the processes involved in VOC oxidation and their reaction products. Recent studies have identified the key contributions of peroxy radicals, organic nitrates and oxygenated VOCs to ambient hydroxyl radical (OH) reactivity, which controls atmospheric lifetimes of most compounds, influencing aerosol and ozone formation.

More such strategic studies are needed to address the failure of models to simulate production of air quality and climate-relevant species, particularly at low-NOx and varied temporal and spatial scales. Recent technological advances show promise in producing the observational data, previously too sparse or time-limited, necessary to fully constrain the chemistry in these models and account for missing OH reactivity.

This session invites presentations highlighting best practice in combining laboratory experiments, in-situ measurements and modelling.

Primary Convener:  Kirsti Ashworth, University of Michigan Ann Arbor, Ann Arbor, MI, United States
Conveners:  Tran Nguyen, California Institute of Technology, Pasadena, United States, Vinayak Sinha, IISER Mohali, Manauli Po, India and William C Porter, Department of Environmental Sciences, University of California, Riverside, United States
Chairs:  Vinayak Sinha, IISER Mohali, Manauli Po, India and Kirsti Ashworth, University of Michigan Ann Arbor, Ann Arbor, MI, United States
OSPA Liaison:  Tran Nguyen, California Institute of Technology, Pasadena, United States

Cross-Listed:
  • B - Biogeosciences
Co-Sponsor(s):
  • IGBP: International Geosphere-Biosphere Programme -
Index Terms:

0305 Aerosols and particles [ATMOSPHERIC COMPOSITION AND STRUCTURE]
0315 Biosphere/atmosphere interactions [ATMOSPHERIC COMPOSITION AND STRUCTURE]
0365 Troposphere: composition and chemistry [ATMOSPHERIC COMPOSITION AND STRUCTURE]
0490 Trace gases [BIOGEOSCIENCES]

Abstracts Submitted to this Session:

Total OH reactivity measurements aboard the Zeppelin NT during the PEGASOS campaigns 2012 and 2013: Spatial and vertical distribution and contribution of substance classes (66067)
Robert Wegener1, Julia Jäger2, Andreas Hofzumahaus1, Hendrik Fuchs3, Sebastian Gomm4, Sebastian Broch3, Rolf Häseler4, Frank Holland1, Ralf Tillmann4, Thomas F Mentel5, Astrid Kiendler-Scharr6, Andreas Wahner6, Jennifer Kaiser7, Keding Lu8, Glenn Wolfe9, Frank N Keutsch10 and Mitchell P Thayer11, (1)Forschungszentrum Jülich GmbH, Jülich 52428, Germany, (2)Scientific Analysis Laboratories Limited, Manchester, United Kingdom, (3)Forschungszentrum Jülich GmbH, Institute of Energy and Climate Research, IEK-8: Troposphere, Jülich, Germany, (4)Forschungszentrum Jülich, Institute of Energy and Climate Research, IEK-8: Troposphere, Jülich, Germany, (5)IEK-8-Troposphere, Juelich, Germany, (6)Forschungszentrum Jülich, Institute of Energy and Climate Research, Troposphere (IEK-8), Jülich, Germany, (7)Georgia Institute of Technology, School of Civil and Environmental Engineering, Atlanta, GA, United States, (8)Peking University, State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Beijing, China, (9)NASA Goddard Space Flight Center, Greenbelt, MD, United States, (10)Harvard University, School of Engineering and Applied Sciences, Department of Chemistry and Chemical Biology and Department of Earth and Planetary Sciences, Cambridge, MA, United States, (11)University of Wisconsin Madison, Chemistry, Madison, WI, United States
Summer 2015 measurements of total OH reactivity at a UK coastal site (77990)
Danny R Cryer1, Robert Woodward-Massey1, Lisa Whalley2,3, Trevor Ingham1,3, Leigh Crilley4, Louisa J Kramer5, Claire Reeves6, Grant Forster6,7, David Oram6,8, Brian Bandy6, Chris Reed9, James D Lee9,10, William Bloss5 and Dwayne E Heard1,3, (1)University of Leeds, School of Chemistry, Leeds, United Kingdom, (2)University of Leeds, School of Chemistry, Leeds, LS2, United Kingdom, (3)National Centre for Atmospheric Science, University of Leeds, Leeds, United Kingdom, (4)University of Birmingham, Birmingham, United Kingdom, (5)University of Birmingham, School of Geography, Earth and Environmental Sciences, Birmingham, United Kingdom, (6)National Centre for Atmospheric Science, Leeds, United Kingdom, (7)School for Environmental Sciences, University of East Anglia, Norwich, United Kingdom, (8)University of East Anglia, Norwich, United Kingdom, (9)Wolfson Atmospheric Chemistry Laboratories, Department of Chemistry, University of York, York, United Kingdom, (10)National Centre for Atmospheric Science, Wolfson Atmospheric Chemistry Laboratories, Department of Chemistry, University of York, York, United Kingdom
Total OH reactivity study from VOC photochemical oxidation in the SAPHIR chamber (79221)
Zhujun Yu1, Ralf Tillmann1, Thorsten Hohaus1, Hendrik Fuchs2, Anna Novelli3, Robert Wegener1, Martin Kaminski1, Sebastian H. Schmitt3, Andreas Wahner1 and Astrid Kiendler-Scharr1, (1)Institute of Energy and Climate Research, IEK-8, Forschungszentrum Jülich, Jülich, Germany, (2)Forschungszentrum Jülich GmbH, Institute of Energy and Climate Research, IEK-8: Troposphere, Jülich, Germany, (3)Forschungszentrum Jülich, Institute of Energy and Climate Research, IEK-8: Troposphere, Jülich, Germany
OH radical reactivity in an Indiana Forest: Measurements and model comparisons (79667)
Pamela Rickly1, Brandon Bottorff2, Michelle Lew3, Philip S Stevens4, Thierry Leonardis5, Nadine Locoge5, Sofia Sklaveniti6, Sebastien Dusanter7, Shuvashish Kundu8, Ezra C D Wood9 and Drew R Gentner10, (1)Indiana University Bloomington, School of Public and Environmental Affairs, Bloomington, IN, United States, (2)Indiana University Bloomington, O'Neill School of Public and Environmental Affairs, Bloomington, United States, (3)Indiana University Bloomington, Chemistry, Bloomington, IN, United States, (4)Indiana University, O'Neill School of Public and Environmental Affairs, Bloomington, United States, (5)IMT Lille Douai, Atmospheric Sciences and Environmental Engineering (SAGE), Douai, France, (6)School of Public and Environmental Affairs, Indiana University, Bloomington, IN, United States, (7)Ecole des Mines de Douai, Douai Cedex, France, (8)University of Iowa, Iowa City, IA, United States, (9)U. of Massachusetts - Amherst, Amherst, United States, (10)Yale University, Department of Chemical and Environmental Engineering, New Haven, CT, United States
Gas-Phase OH Oxidation of Cresol to Yield Highly Oxygenated Products (81364)
Rebecca Schwantes1, Hanna Lignell2, Renee McVay1, Katherine Schilling3, Matthew Mitchell Coggon4, Xuan Zhang1 and John Seinfeld5, (1)California Institute of Technology, Pasadena, CA, United States, (2)Univ California, Irvine, CA, United States, (3)U.S. Army Criminal Investigation Laboratory, Forest Park, GA, United States, (4)National Oceanic and Atmospheric Administration/U.S. Department of Commerce operative Institute for Research in Environmental Sciences/Chemical Sciences Division Boulder 80309 (United States), operative Institute for Research in Environmental Sciences/Chemical Sciences Division, Boulder, United States, (5)California Institute of Technology, Department of Chemical Engineering, Pasadena, United States
Competition between functionalization and fragmentation pathways in the OH-initiated oxidation of aqueous tartaric acid droplets: Reaction products and model simulations (64172)
Chiu Tung Cheng1, Chun Yin Chow1, Man Nin Chan2, Andreas Zuend3, Thomas Berkemeier4 and Manabu Shiraiwa5, (1)Chinese University of Hong Kong, Hong Kong, Hong Kong, (2)The Chinese University of Hong Kong, Hong Kong, China, (3)McGill University, Department of Atmospheric and Oceanic Sciences, Montreal, QC, Canada, (4)Max Planck Institute for Chemistry, Multiphase Chemistry Department, Mainz, Germany, (5)Max Planck Institute for Chemistry, Mainz, Germany
The Reactive-Diffusive Length of OH Radical in Squalane (62656)
Lance Lee and Kevin R Wilson, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
Laboratory and Ambient Measurements of Oxidized Organic Compounds in the Gas Phase Using Nitrate Ion Chemical Ionization Coupled with High Resolution Time-of-Flight Mass Spectrometry (61991)
Paola Massoli1, Harald Stark2,3, Manjula R Canagaratna1, Jordan Krechmer4, Andrew T Lambe3, Gabriel A Isaacman-VanWertz5, John B Nowak6, Joel Kimmel7, Jesse H Kroll8, John Toulson Jayne9 and Douglas R Worsnop1, (1)Aerodyne Research Inc., Billerica, MA, United States, (2)Cooperative Institute for Research in Environmental Sciences, Boulder, CO, United States, (3)Aerodyne Research Inc., Billerica, United States, (4)University of Colorado at Boulder, Boulder, United States, (5)Massachusetts Institute of Technology, Cambridge, MA, United States, (6)NASA Langley Research Center, Hampton, VA, United States, (7)Tofwerk AG, Thun, Switzerland, (8)Massachusetts Institute of Technology, Civil and Environmental Engineering, Cambridge, United States, (9)Aerodyne Research Inc, Billerica, MA, United States
Distribution of Gaseous and Particulate Organic Peroxides Formed in the Ozonolysis of α-Pinene (76500)
Huan Li1, Zhongming Chen2, Liubin Huang1 and Dao Huang1,3, (1)Peking University, Beijing, China, (2)Peking University, College of Environmental Sciences and Engineering, Beijing, China, (3)Zhejiang University, Hangzhou, China
Sources and Fate of Reactive Carbon in an Isoprene-Dominated Forest (75247)
Jennifer Kaiser1, Kate Skog2, Karsten Baumann3, Steven B Bertman4, Steven S Brown5, William H Brune6, John D Crounse7, Joost A de Gouw5, Eric S Edgerton8, Philip Allen Feiner6, Allen H Goldstein9, Abigail Koss10, Pawel K Misztal9, Tran Nguyen11, Kevin Frederick Olson9, Jason Michael St Clair12, Alex Teng13, Paul O Wennberg14, Robert J Wild15, Li Zhang16 and Frank N Keutsch17, (1)Georgia Institute of Technology, School of Civil and Environmental Engineering, Atlanta, GA, United States, (2)Picarro, Inc., Santa Clara, CA, United States, (3)Atmospheric Research and Analysis, Morrisville, NC, United States, (4)Western Michigan University, Kalamazoo, MI, United States, (5)NOAA Boulder, Boulder, CO, United States, (6)Pennsylvania State University, University Park, PA, United States, (7)California Institute of Technology, Division of Geological and Planetary Sciences, Pasadena, CA, United States, (8)Atmospheric Research & Analysis, Inc., Cary, NC, United States, (9)University of California Berkeley, Berkeley, CA, United States, (10)University of Colorado at Boulder, Boulder, CO, United States, (11)California Institute of Technology, Pasadena, United States, (12)NASA Goddard Space Flight Center, Atmospheric Chemistry and Dynamics Lab, Greenbelt, MD, United States, (13)California Institute of Technology, Pasadena, CA, United States, (14)California Institute of Technology, Division of Engineering and Applied Science, Pasadena, United States, (15)Colorado University/NOAA/ESRL, Boulder, CO, United States, (16)Pennsylvania State Univ, University Park, PA, United States, (17)Harvard University, School of Engineering and Applied Sciences, Department of Chemistry and Chemical Biology and Department of Earth and Planetary Sciences, Cambridge, MA, United States
The Global Reactive Carbon Budget of the Troposphere (67437)
Sarah Safieddine, Massachusetts Institute of Technology, Cambridge, MA, United States and Colette L Heald, Massachusetts Institute of Technology, Civil and Environmental Engineering, Cambridge, MA, United States
Kinetics Studies of the Photochemistry of Isoprene-derived 4,1-nitrooxyaldehyde (61916)
Fulizi Xiong, Purdue University, West Lafayette, IN, United States and Paul B Shepson, Stony Brook University, School of Marine and Atmospheric Sciences, Stony Brook, United States
On the Role of Organic Nitrates, RONO2, in the NOx Budget: Constraints from Measurements During SOAS (67649)
Paul Romer Present1, Kaitlin Duffey1, Robert J Wild2, Abigail Koss3, Joost A de Gouw4, Kevin Frederick Olson1, Allen H Goldstein1, Philip Allen Feiner5, Li Zhang6, William H Brune7, Juliane Fry8, Hannah M Allen9, Benjamin R Ayres10, Danielle Draper10, Steven S Brown4, Alex Teng11, Tran Nguyen12, John D Crounse9, Paul O Wennberg13, Paul J Wooldridge14 and Ronald C Cohen15, (1)University of California Berkeley, Berkeley, CA, United States, (2)Colorado University/NOAA/ESRL, Boulder, CO, United States, (3)University of Colorado at Boulder, Boulder, CO, United States, (4)NOAA Boulder, Boulder, CO, United States, (5)Pennsylvania State University Main Campus, University Park, PA, United States, (6)Pennsylvania State Univ, University Park, PA, United States, (7)Pennsylvania State University, University Park, PA, United States, (8)Reed College, Dept. of Chemistry, Portland, OR, United States, (9)California Institute of Technology, Division of Geological and Planetary Sciences, Pasadena, CA, United States, (10)Reed College, Portland, OR, United States, (11)California Institute of Technology, Pasadena, CA, United States, (12)California Institute of Technology, Pasadena, United States, (13)California Institute of Technology, Division of Engineering and Applied Science, Pasadena, United States, (14)University of California, Dept. of Chemistry, Berkeley, CA, United States, (15)University of California, Berkeley, Berkeley, United States
The Role of Organic Nitrates in the Chemistry of the Continents: An Assessment Using WRF-CHEM (75106)
Azimeh Zare1, Ronald C Cohen2 and Paul Romer Present1, (1)University of California Berkeley, Berkeley, CA, United States, (2)University of California, Berkeley, Berkeley, United States
Elevated Levels of Carbonyl Compounds in the Atmosphere of Eastern Himalaya in India (71957)
Chirantan Sarkar1, Abhijit Chatterjee2, Dipanjali Majumdar3, Sibaji Raha1, Sanjay Kumar Ghosh1 and Anjali Srivastava4, (1)Bose Institute, Kolkata, India, (2)Bose Institute, Environmental Sciences Section, Kolkata, India, (3)National Environmental Engineering Research Institute, Kolkta, India, (4)National Environmental Engineering Research Institute, New Delhi, India
Formaldehyde in the Tropical Western Pacific: Evaluation of model chemistry and emissions with in situ observations (67001)
Daniel C Anderson1, Julie M Nicely1, Ross J Salawitch2, Glenn M Wolfe3, Thomas F Hanisco4, Russell R Dickerson1, Eric C Apel5, Elliot L Atlas6, Sunil Baidar7, Nicola J Blake8, Teresa Lynn Campos9, Dexian Chen10, Barbara Dix11, Rafael Fernandez12, L Gregory Huey13, Douglas Edward Kinnison14, Theodore Konstantinos Koenig15, Samuel R Hall16, Rebecca S Hornbrook9, J F Lamarque17, Laura Pan18, Daniel D Riemer19, Alfonso Saiz-Lopez20, David Tanner21, Kirk Ullmann16, Rainer M Volkamer22, Andrew John Weinheimer23, Michael Robert Le Breton24, Carl Percival25 and Thomas Bannan24, (1)University of Maryland College Park, College Park, MD, United States, (2)University of Maryland, AOSC and Chemistry, College Park, United States, (3)NASA Goddard Space Flight Center, Greenbelt, United States, (4)NASA Goddard Space Flight Center, Greenbelt, MD, United States, (5)University Corporation for Atmospheric Research, Boulder, CO, United States, (6)University of Miami, Miami, United States, (7)CIRES, University of Colorado Boulder/NOAA Chemical Sciences Laboratory, Boulder, CO, United States, (8)University of California Irvine, Irvine, CA, United States, (9)National Center for Atmospheric Research, Atmospheric Chemistry Observations & Modeling Laboratory, Boulder, CO, United States, (10)Georgia Institute of Technology Main Campus, School of Earth and Atmospheric Sciences, Atlanta, GA, United States, (11)University of Colorado at Boulder, Boulder, CO, United States, (12)Institute of Physical Chemistry Rocasolano, CSIC, Madrid, Spain, (13)Georgia Institute of Technology Main Campus, Atlanta, GA, United States, (14)National Center for Atmospheric Research, Boulder, United States, (15)University of Colorado at Boulder, Department of Chemistry and Biochemistry, Boulder, CO, United States, (16)National Center for Atmospheric Research (NCAR), Atmospheric Chemistry Observations and Modeling Laboratory, Boulder, CO, United States, (17)National Center for Atmospheric Research, Boulder, CO, United States, (18)National Center for Atmospheric Research, Atmospheric Chemistry Observations & Modeling, Boulder, CO, United States, (19)Self Employed, Washington, DC, United States, (20)Spanish National Research Council, Department of Atmospheric Chemistry and Climate, Institute of Physical Chemistry Rocasolano (CSIC), Madrid, Spain, (21)Georgia Institute of Technology Main Campus, School of Earth and Atmospheric Sciences, Atlanta, United States, (22)University of Colorado at Boulder, Cooperative Institute for Research in Environmental Sciences (CIRES) and Department of Chemistry, Boulder, United States, (23)National Center for Atmospheric Research, Atmospheric Chemistry Observations and Modeling Laboratory, Boulder, United States, (24)University of Manchester, Manchester, M13, United Kingdom, (25)University of Manchester, Manchester, United Kingdom
Secondary Organic Aerosol Formation and Aging in a Flow Reactor in the Forested Southeast US during SOAS (63883)
Weiwei Hu1, Brett B Palm2, Lina Hacker3, Pedro Campuzano Jost4, Doug A Day5, Suzane S de Sá6, Benjamin R Ayres7, Danielle Draper7, Juliane Fry8, Amber M Ortega4, Astrid Kiendler-Scharr9, Aki Pajunoja10, Annele Virtanen10, Jordan Krechmer2, Manjula R Canagaratna11, Samantha Thompson4, Reddy L. N. Yatavelli4, Harald Stark12,13, Douglas R Worsnop11, Scot T Martin14, Delphine Farmer15, Steven S Brown16 and Jose L Jimenez4, (1)Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, China, (2)University of Colorado at Boulder, Boulder, United States, (3)Forschungszentrum Jülich GmbH, Jülich 52428, Germany, (4)University of Colorado at Boulder, Boulder, CO, United States, (5)University of Colorado at Boulder, Department of Chemistry, Boulder, United States, (6)Harvard University, School of Engineering and Applied Sciences, Cambridge, MA, United States, (7)Reed College, Portland, OR, United States, (8)Reed College, Chemistry and Environmental Studies, Portland, OR, United States, (9)Forschungszentrum Jülich GmbH, Institute of Energy and Climate Research, IEK-8: Troposphere, Jülich, Germany, (10)Department of Applied Physics, University of Eastern Finland, Joensuu, Finland, (11)Aerodyne Research Inc., Billerica, MA, United States, (12)University of Colorado at Boulder, Cooperative Institute for Research in Environmental Sciences (CIRES) and Department of Chemistry, Boulder, United States, (13)Aerodyne Research Inc., Billerica, United States, (14)Harvard University, Department of Earth and Planetary Sciences, Cambridge, MA, United States, (15)Colorado State University, Department of Chemistry, Fort Collins, United States, (16)NOAA Boulder, Boulder, CO, United States
Incremental Reactivity Effects of Anthropogenic and Biogenic Volatile Organic Compounds on Secondary Organic Aerosol Formation (63662)
Mary Kacarab1, Lijie Li2, William Samuel Carter1 and David R Cocker III1, (1)University of California Riverside, Riverside, CA, United States, (2)California Institute of Technology, Environmental Science and Engineering, Pasadena, CA, United States
Transient Absorption Spectroscopy of C1 and C2 Criegee Intermediates: UV Spectrum and Reaction Kinetics (65038)
Mica C Smith1, Wen Chao2,3, Allen Ting4, Chun-Hung Chang4, Liang-Chun Lin3,4, Kaito Takahashi5, Kristie A Boering6 and Jim Jr-Min Lin4,7, (1)University of California Berkeley, Chemistry, Berkeley, CA, United States, (2)California Institute of Technology, Pasadena, United States, (3)National Taiwan University, Chemistry, Taipei, Taiwan, (4)Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan, (5)Academia Sinica, Institute of Atomic and Molecular Sciences, Taipei, Taiwan, (6)University of California Berkeley, Chemistry and Earth & Planetary Science, Berkeley, CA, United States, (7)National Taiwan University, Department of Chemistry, Taipei, Taiwan
Role of Criegee Intermediates in Formation of Sulfuric Acid at BVOCs-rich Cape Corsica Site (71950)
Alexandre Kukui1, Sebastien Dusanter2,3, Stéphane Sauvage4, Valerie Gros5, Thierry Bourrianne6, Karine Sellegri7, Jinhe Wang8, Aurélie Colomb7, Jean-Marc Pichon7, Hui Chen8,9, Cerise Kalogridis10, Nora Zannoni10, Bernard Bonsang10, Vincent Michoud4, Nadine Locoge11 and Thiery Leonardis11, (1)Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), CNRS, Orléans, France, (2)Indiana University, School of Public and Envrionmental Affairs, Bloomington, IN, United States, (3)Mines Douai, Douai, France, (4)Centre for Energy and Environment, IMT Nord Europe, Lille, France, (5)UMR CNRS-CEA-UVSQ, IPSL, Univ. Paris-Saclay, Laboratoire des Sciences du Climat et de l'Environnement, Gif-Sur-Yvette Cedex, France, (6)Météo France, CNRS, CNRM-GAME, Toulouse, France, (7)Laboratoire de Météorologie Physique Observatoire de Physique du Globe de Clermont-Ferrand, Aubiere Cedex, France, (8)Fudan Univ, Shanghai Key Lab Atmospher Particle Pollut & Prev, Dept Environm Sci & Engn, Shanghai, China, (9)ICARE, CNRS, Orléans, France, (10)Laboratoire des Sciences du Climat et de l'Environnement, Gif-Sur-Yvette Cedex, France, (11)Mines Douai, Atmospheric Sciences and Environmental Engineering (SAGE), F-59508 Douai, France
Anthropogenic Sulfur Perturbations on Biogenic Oxidation: Impacts of Sulfur Dioxide Additions on Bulk Gas Phase OH Oxidation Products of Alpha and Beta Pinene. (65208)
Beth Friedman, Colorado State University, Department of Chemistry, Fort Collins, CO, United States, Patrick Brophy, Colorado State University, Fort Collins, CO, United States, William H Brune, Pennsylvania State University, University Park, PA, United States and Delphine Farmer, Colorado State University, Department of Chemistry, Fort Collins, United States
Aldol Condensation Products and Polyacetals in Organic Films Formed from Reactions of Propanal in Sulfuric Acid at Upper Troposphere/Lower Stratosphere (UT/LS) Aerosol Acidities (85793)
Julie Van Hong Bui1, Saul Perez-Montano1, Eric S. W. Li1, Thomas E. Nelson1, Kieu T Ha1, Linda Leong1, Laura T Iraci2 and Annalise L Van Wyngarden3, (1)San Jose State University, San Jose, CA, United States, (2)NASA Ames Research Center, Moffett Field, CA, United States, (3)San Jose State University, Department of Chemistry, San Jose, CA, United States
Investigations of Acetate Chemical Ionization Mass Spectrometry (NIPT-CIMS): Underlying Chemistry, Calibrations, and Operational Considerations for the Detection of Carboxylic Acids and Other Species (65597)
Patrick Brophy, Colorado State University, Fort Collins, CO, United States and Delphine Farmer, Colorado State University, Department of Chemistry, Fort Collins, United States

See more of: Atmospheric Sciences