Sample records for agric food chem

  1. NutriChem: a systems chemical biology resource to explore the medicinal value of plant-based foods.

    PubMed

    Jensen, Kasper; Panagiotou, Gianni; Kouskoumvekaki, Irene

    2015-01-01

    There is rising evidence of an inverse association between chronic diseases and diets characterized by rich fruit and vegetable consumption. Dietary components may act directly or indirectly on the human genome and modulate multiple processes involved in disease risk and disease progression. However, there is currently no exhaustive resource on the health benefits associated to specific dietary interventions, or a resource covering the broad molecular content of food. Here we present the first release of NutriChem, available at http://cbs.dtu.dk/services/NutriChem-1.0, a database generated by text mining of 21 million MEDLINE abstracts for information that links plant-based foods with their small molecule components and human disease phenotypes. NutriChem contains text-mined data for 18478 pairs of 1772 plant-based foods and 7898 phytochemicals, and 6242 pairs of 1066 plant-based foods and 751 diseases. In addition, it includes predicted associations for 548 phytochemicals and 252 diseases. To the best of our knowledge this database is the only resource linking the chemical space of plant-based foods with human disease phenotypes and provides a foundation for understanding mechanistically the consequences of eating behaviors on health. © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.

  2. Studies of Effects of Particle Size on The Toxicity of Insecticide Aerosols

    DTIC Science & Technology

    1976-09-01

    phosphorothioate in rats. J. Agric. Food Chem. 15:132-138. Speck, R.J. and Wolochow, H. 1957. Studies on epidemiol ,gy of respiratory infections. V111...Comparison of formulations Samples of pesticide formulations for use in the toxicological studies discussed were normally obtained direct from the manufact

  3. Enhanced Oxidative Bioremediation of cis-dichloroethene (cis-DCE) and Vinyl Chloride (VC) using Electron Shuttles

    DTIC Science & Technology

    2009-07-01

    1989) Abiotic Reduction of Nitro Aromatic Pesticides in Anaerobic Laboratory Systems. J, Agric, Food Chem, 37: 248. 13 Doménech-Carbó A., Doménech-Carbó...in general. Agricultural Use Humic acids have been used for decades as soil amendments and adjuvants for pesticide formulations for various food...necessary" to support an exception tolerance for pesticide formulations (EPA 2000, Federal Register, July 18, Vol 65, Number 138). Further, materials

  4. Non-Ionic Highly Permeable Polymer Shells for Encapsulation of Living Cells

    DTIC Science & Technology

    2011-05-01

    I would like to thank Irina Drachuk for her extensive assistance in data collection and analysis , and Drs. Veronika Kozlovskaya and Olga Shchepelina...considered complete when the intensity of the photobleached region stabilized. The quantitative analysis was performed using ImageJ software, and curve...E., Tannin -protein complexes as radical scavengers and radical sinks. J Agric Food Chem 2001, 49 (10), 4917-23. 53. Lopes, G. K.; Schulman, H. M

  5. Chemical Composition, Antifungal and Insecticidal Activities of Hedychium Essential Oils

    DTIC Science & Technology

    2013-04-11

    of wildcrafted biomass would probably have to be combined during the commercial production of a botanical pesticide . Therefore, it seems likely...S.I. Content, composition, and bioactivity of the essential of three basil genotypes as a function of harvesting. J. Agric. Food Chem. 2008, 56, 380...throughput screening method to identify potential pesticides for mosquito control. J. Med. Entomol. 2009, 46, 335–341. 28. Anderson, J.T.; Thorvilson, G.H

  6. Epigenetic Programming of Breast Cancer and Nutrition Prevention

    DTIC Science & Technology

    2012-05-01

    to control (Figure 2). Maternal dietary supplementation with Res reduced by ~60% DNMT1 occupancy on the BRCA-1 promoter, compared with TCDD exposed...2009;75:1227–30. [57] Jeuken A, Keser BJ, Khan E, Brouwer A, Koeman J, DenisonMS. Activation of the Ah receptor by extracts of dietary herbal ... supplements , vegetables, and fruits. J Agric Food Chem 2003;51:5478–87. [58] Amakura Y, Tsutsumi T, Sasaki K, Nakamura M, Yoshida T, Maitani T. Influence of

  7. Estrogen and the Dietary Phytoestrogen Resveratrol as Regulators of the Rho GTPase Rac in Breast Cancer Research

    DTIC Science & Technology

    2009-06-01

    toxicity of a red grape wine flavonoid fraction against MCF 7 cells. Breast Cancer Res Treat 85:65 79. doi:10.1023/B: BREA.0000021048.52430.c0 10...Major flavonoids in grape seeds and skins: antioxidant capacity of catechin, epicatechin, and gallic acid. J Agric Food Chem 52:255 260. doi:10.1021...The effect of the flavonoid diosmin, grape seed extract and red wine on the pul monary metastatic B16F10 melanoma. Histol Histopathol 20:1121 1129 Clin

  8. Analysis of 2-alkylcyclobutanones in cashew nut, nutmeg, apricot kernel, and pine nut samples: re-evaluating the uniqueness of 2-alkylcyclobutanones for irradiated food identification.

    PubMed

    Leung, Elvis M K; Tang, Phyllis N Y; Ye, Yuran; Chan, Wan

    2013-10-16

    2-Alkylcyclobutanones (2-ACBs) have long been considered as unique radiolytic products that can be used as indicators for irradiated food identification. A recent report on the natural existence of 2-ACB in non-irradiated nutmeg and cashew nut samples aroused worldwide concern because it contradicts the general belief that 2-ACBs are specific to irradiated food. The goal of this study is to test the natural existence of 2-ACBs in nut samples using our newly developed liquid chromatography-tandem mass spectrometry (LC-MS/MS) method with enhanced analytical sensitivity and selectivity ( Ye , Y. ; Liu , H. ; Horvatovich , P. ; Chan , W. Liquid chromatography-electrospray ionization tandem mass spectrometric analysis of 2-alkylcyclobutanones in irradiated chicken by precolumn derivatization with hydroxylamine . J. Agric. Food Chem. 2013 , 61 , 5758 - 5763 ). The validated method was applied to identify 2-dodecylcyclobutanone (2-DCB) and 2-tetradecylcyclobutanone (2-TCB) in nutmeg, cashew nut, pine nut, and apricot kernel samples (n = 22) of different origins. Our study reveals that 2-DCB and 2-TCB either do not exist naturally or exist at concentrations below the detection limit of the existing method. Thus, 2-DCB and 2-TCB are still valid to be used as biomarkers for identifying irradiated food.

  9. PubChemSR: A search and retrieval tool for PubChem

    PubMed Central

    Hur, Junguk; Wild, David J

    2008-01-01

    Background Recent years have seen an explosion in the amount of publicly available chemical and related biological information. A significant step has been the emergence of PubChem, which contains property information for millions of chemical structures, and acts as a repository of compounds and bioassay screening data for the NIH Roadmap. There is a strong need for tools designed for scientists that permit easy download and use of these data. We present one such tool, PubChemSR. Implementation PubChemSR (Search and Retrieve) is a freely available desktop application written for Windows using Microsoft .NET that is designed to assist scientists in search, retrieval and organization of chemical and biological data from the PubChem database. It employs SOAP web services made available by NCBI for extraction of information from PubChem. Results and Discussion The program supports a wide range of searching techniques, including queries based on assay or compound keywords and chemical substructures. Results can be examined individually or downloaded and exported in batch for use in other programs such as Microsoft Excel. We believe that PubChemSR makes it straightforward for researchers to utilize the chemical, biological and screening data available in PubChem. We present several examples of how it can be used. PMID:18482452

  10. Literature information in PubChem: associations between PubChem records and scientific articles.

    PubMed

    Kim, Sunghwan; Thiessen, Paul A; Cheng, Tiejun; Yu, Bo; Shoemaker, Benjamin A; Wang, Jiyao; Bolton, Evan E; Wang, Yanli; Bryant, Stephen H

    2016-01-01

    PubChem is an open archive consisting of a set of three primary public databases (BioAssay, Compound, and Substance). It contains information on a broad range of chemical entities, including small molecules, lipids, carbohydrates, and (chemically modified) amino acid and nucleic acid sequences (including siRNA and miRNA). Currently (as of Nov. 2015), PubChem contains more than 150 million depositor-provided chemical substance descriptions, 60 million unique chemical structures, and 225 million biological activity test results provided from over 1 million biological assay records. Many PubChem records (substances, compounds, and assays) include depositor-provided cross-references to scientific articles in PubMed. Some PubChem contributors provide bioactivity data extracted from scientific articles. Literature-derived bioactivity data complement high-throughput screening (HTS) data from the concluded NIH Molecular Libraries Program and other HTS projects. Some journals provide PubChem with information on chemicals that appear in their newly published articles, enabling concurrent publication of scientific articles in journals and associated data in public databases. In addition, PubChem links records to PubMed articles indexed with the Medical Subject Heading (MeSH) controlled vocabulary thesaurus. Literature information, both provided by depositors and derived from MeSH annotations, can be accessed using PubChem's web interfaces, enabling users to explore information available in literature related to PubChem records beyond typical web search results. Graphical abstractLiterature information for PubChem records is derived from various sources.

  11. Preface to Special Issue of ChemSusChem on Perovskite Optoelectronics.

    PubMed

    Bolink, Henk J; Mhaisalkar, Subodh G

    2017-10-09

    This Editorial introduces one of two companion Special Issues on "Halide Perovskites for Optoelectronics Applications" in ChemSusChem and Energy Technology following the ICMAT 2017 Conference in Singapore. More information on the other Special Issue can be found in the Editorial published in Energy Technology. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Exploiting PubChem for Virtual Screening

    PubMed Central

    Xie, Xiang-Qun

    2011-01-01

    Importance of the field PubChem is a public molecular information repository, a scientific showcase of the NIH Roadmap Initiative. The PubChem database holds over 27 million records of unique chemical structures of compounds (CID) derived from nearly 70 million substance depositions (SID), and contains more than 449,000 bioassay records with over thousands of in vitro biochemical and cell-based screening bioassays established, with targeting more than 7000 proteins and genes linking to over 1.8 million of substances. Areas covered in this review This review builds on recent PubChem-related computational chemistry research reported by other authors while providing readers with an overview of the PubChem database, focusing on its increasing role in cheminformatics, virtual screening and toxicity prediction modeling. What the reader will gain These publicly available datasets in PubChem provide great opportunities for scientists to perform cheminformatics and virtual screening research for computer-aided drug design. However, the high volume and complexity of the datasets, in particular the bioassay-associated false positives/negatives and highly imbalanced datasets in PubChem, also creates major challenges. Several approaches regarding the modeling of PubChem datasets and development of virtual screening models for bioactivity and toxicity predictions are also reviewed. Take home message Novel data-mining cheminformatics tools and virtual screening algorithms are being developed and used to retrieve, annotate and analyze the large-scale and highly complex PubChem biological screening data for drug design. PMID:21691435

  13. PubChem promiscuity: a web resource for gathering compound promiscuity data from PubChem.

    PubMed

    Canny, Stephanie A; Cruz, Yasel; Southern, Mark R; Griffin, Patrick R

    2012-01-01

    Promiscuity counts allow for a better understanding of a compound's assay activity profile and drug potential. Although PubChem contains a vast amount of compound and assay data, it currently does not have a convenient or efficient method to obtain in-depth promiscuity counts for compounds. PubChem promiscuity fills this gap. It is a Java servlet that uses NCBI Entrez (eUtils) web services to interact with PubChem and provide promiscuity counts in a variety of categories along with compound descriptors, including PAINS-based functional group detection. http://chemutils.florida.scripps.edu/pcpromiscuity southern@scripps.edu

  14. PubChem promiscuity: a web resource for gathering compound promiscuity data from PubChem

    PubMed Central

    Canny, Stephanie A.; Cruz, Yasel; Southern, Mark R.; Griffin, Patrick R.

    2012-01-01

    Summary: Promiscuity counts allow for a better understanding of a compound's assay activity profile and drug potential. Although PubChem contains a vast amount of compound and assay data, it currently does not have a convenient or efficient method to obtain in-depth promiscuity counts for compounds. PubChem promiscuity fills this gap. It is a Java servlet that uses NCBI Entrez (eUtils) web services to interact with PubChem and provide promiscuity counts in a variety of categories along with compound descriptors, including PAINS-based functional group detection. Availability: http://chemutils.florida.scripps.edu/pcpromiscuity Contact: southern@scripps.edu PMID:22084255

  15. PubChem BioAssay: 2017 update

    PubMed Central

    Wang, Yanli; Bryant, Stephen H.; Cheng, Tiejun; Wang, Jiyao; Gindulyte, Asta; Shoemaker, Benjamin A.; Thiessen, Paul A.; He, Siqian; Zhang, Jian

    2017-01-01

    PubChem's BioAssay database (https://pubchem.ncbi.nlm.nih.gov) has served as a public repository for small-molecule and RNAi screening data since 2004 providing open access of its data content to the community. PubChem accepts data submission from worldwide researchers at academia, industry and government agencies. PubChem also collaborates with other chemical biology database stakeholders with data exchange. With over a decade's development effort, it becomes an important information resource supporting drug discovery and chemical biology research. To facilitate data discovery, PubChem is integrated with all other databases at NCBI. In this work, we provide an update for the PubChem BioAssay database describing several recent development including added sources of research data, redesigned BioAssay record page, new BioAssay classification browser and new features in the Upload system facilitating data sharing. PMID:27899599

  16. AdapChem

    NASA Technical Reports Server (NTRS)

    Oluwole, Oluwayemisi O.; Wong, Hsi-Wu; Green, William

    2012-01-01

    AdapChem software enables high efficiency, low computational cost, and enhanced accuracy on computational fluid dynamics (CFD) numerical simulations used for combustion studies. The software dynamically allocates smaller, reduced chemical models instead of the larger, full chemistry models to evolve the calculation while ensuring the same accuracy to be obtained for steady-state CFD reacting flow simulations. The software enables detailed chemical kinetic modeling in combustion CFD simulations. AdapChem adapts the reaction mechanism used in the CFD to the local reaction conditions. Instead of a single, comprehensive reaction mechanism throughout the computation, a dynamic distribution of smaller, reduced models is used to capture accurately the chemical kinetics at a fraction of the cost of the traditional single-mechanism approach.

  17. Chem-2-Chem: A One-to-One Supportive Learning Environment for Chemistry

    NASA Astrophysics Data System (ADS)

    Báez-Galib, Rosita; Colón-Cruz, Héctor; Resto, Wilfredo; Rubin, Michael R.

    2005-12-01

    The Chem-2-Chem (C2C) tutoring mentoring program was developed at the University of Puerto Rico at Cayey, an undergraduate institution serving Hispanic students, to increase student retention and help students achieve successful general chemistry course outcomes. This program provides a supportive learning environment designed to address students' academic and emotional needs in a holistic way. Advanced chemistry students offered peer-led, personalized, and individualized learning experiences through tutoring and mentoring to approximately 21% of students enrolled in the general chemistry course. Final grades from official class lists of all general chemistry course sections were analyzed using Student's t -test, paired t -test, and χ 2 analysis. Results during the seven semesters studied show an increase of 29% in successful course outcomes defined as final letter grades of A, B, and C obtained by Chem-2-Chem participants. For each final grade, highly statistically significant differences between participants and nonparticipants were detected. There were also statistically significant differences between successful course outcomes obtained by participants and nonparticipants for each of the semesters studied. This research supports recent trends in chemical education to provide a social context for learning experiences. This peer-led learning strategy can serve as an effective model to achieve excellence in science courses at a wide range of educational institutions.

  18. Checking out ChemCam View

    NASA Image and Video Library

    2012-08-17

    This mosaic shows the calibration target for the Chemistry and Camera ChemCam instrument on NASA Curiosity rover, as seen by the ChemCam remote micro-imager. The 10 images incorporated in this mosaic were taken on Aug. 15.

  19. LANL Researcher Roger Wiens Discusses ChemCam

    ScienceCinema

    Wiens, Roger

    2018-01-16

    Discussion of the ChemCam instrument on the Curiosity Rover that occurred during the NASA press conference prior to launch of the Mars Science Laboratory. The ChemCam instrument was developed by Los Alamos National Laboratory and the French Space Institute. Los Alamos National Laboratory researcher Roger Wiens discusses the instrument on this video. ChemCam uses a laser to "zap" features of the Martian landscape and then uses a spectrometer to gather information about the composition of the sample. ChemCam will help the Curiosity Rover determine whether Mars is or was habitable. The Rover is expected to touch down on the Red Planet on August 5, 2012.

  20. Chem-Braze Abradable Seal Attachment

    DTIC Science & Technology

    1980-05-01

    bonding system for attaching sintered abradable seals such as FELTMETAL® to titanium -, steel- and nickel-base compressor blade tip-shrouds has been... blade tip-shrouds was developed. The improved Chem-Braze system incorporates glycerin as an inhibitor to prevent premature evaporation which prolongs...compressor blade tip-shrouds using the improved Chem-Braze system compared to attachment with gold-nickel braze. p. p. FORM . . yn

  1. LANL Researcher Roger Wiens Discusses ChemCam

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wiens, Roger

    2012-02-15

    Discussion of the ChemCam instrument on the Curiosity Rover that occurred during the NASA press conference prior to launch of the Mars Science Laboratory. The ChemCam instrument was developed by Los Alamos National Laboratory and the French Space Institute. Los Alamos National Laboratory researcher Roger Wiens discusses the instrument on this video. ChemCam uses a laser to "zap" features of the Martian landscape and then uses a spectrometer to gather information about the composition of the sample. ChemCam will help the Curiosity Rover determine whether Mars is or was habitable. The Rover is expected to touch down on the Redmore » Planet on August 5, 2012.« less

  2. A Java API for working with PubChem datasets.

    PubMed

    Southern, Mark R; Griffin, Patrick R

    2011-03-01

    PubChem is a public repository of chemical structures and associated biological activities. The PubChem BioAssay database contains assay descriptions, conditions and readouts and biological screening results that have been submitted by the biomedical research community. The PubChem web site and Power User Gateway (PUG) web service allow users to interact with the data and raw files are available via FTP. These resources are helpful to many but there can also be great benefit by using a software API to manipulate the data. Here, we describe a Java API with entity objects mapped to the PubChem Schema and with wrapper functions for calling the NCBI eUtilities and PubChem PUG web services. PubChem BioAssays and associated chemical compounds can then be queried and manipulated in a local relational database. Features include chemical structure searching and generation and display of curve fits from stored dose-response experiments, something that is not yet available within PubChem itself. The aim is to provide researchers with a fast, consistent, queryable local resource from which to manipulate PubChem BioAssays in a database agnostic manner. It is not intended as an end user tool but to provide a platform for further automation and tools development. http://code.google.com/p/pubchemdb.

  3. Readying ChemCam

    NASA Image and Video Library

    2012-08-17

    This image shows the calibration target for the Chemistry and Camera ChemCam instrument on NASA Curiosity rover. The calibration target is one square and a group of nine circles that look dark in the black-and-white image.

  4. Local Food Systems Food Safety Concerns.

    PubMed

    Chapman, Benjamin; Gunter, Chris

    2018-04-01

    Foodborne disease causes an estimated 48 million illnesses and 3,000 deaths annually (Scallan E, et al., Emerg Infect Dis 17:7-15, 2011), with U.S. economic costs estimated at $152 billion to $1.4 trillion annually (Roberts T, Am J Agric Econ 89:1183-1188, 2007; Scharff RL, http://www.pewtrusts.org/en/research-and-analysis/reports/0001/01/01/healthrelated-costs-from-foodborne-illness-in-the-united-states, 2010). An increasing number of these illnesses are associated with fresh fruits and vegetables. An analysis of outbreaks from 1990 to 2003 found that 12% of outbreaks and 20% of outbreak-related illnesses were associated with produce (Klein S, Smith DeWaal CS, Center for Science in the Public Interest, https://cspinet.org/sites/default/files/attachment/ddreport.pdf, June 2008; Lynch M, Tauxe R, Hedberg C, Epidemiol Infect 137:307-315, 2009). These food safety problems have resulted in various stakeholders recommending the shift to a more preventative and risk-based food safety system. A modern risk-based food safety system takes a farm-to-fork preventative approach to food safety and relies on the proactive collection and analysis of data to better understand potential hazards and risk factors, to design and evaluate interventions, and to prioritize prevention efforts. Such a system focuses limited resources at the points in the food system with the likelihood of having greatest benefit to public health. As shared kitchens, food hubs, and local food systems such as community supported agriculture are becoming more prevalent throughout the United States, so are foodborne illness outbreaks at these locations. At these locations, many with limited resources, food safety methods of prevention are rarely the main focus. This lack of focus on food safety knowledge is why a growing number of foodborne illness outbreaks are occurring at these locations.

  5. A Java API for working with PubChem datasets

    PubMed Central

    Southern, Mark R.; Griffin, Patrick R.

    2011-01-01

    Summary: PubChem is a public repository of chemical structures and associated biological activities. The PubChem BioAssay database contains assay descriptions, conditions and readouts and biological screening results that have been submitted by the biomedical research community. The PubChem web site and Power User Gateway (PUG) web service allow users to interact with the data and raw files are available via FTP. These resources are helpful to many but there can also be great benefit by using a software API to manipulate the data. Here, we describe a Java API with entity objects mapped to the PubChem Schema and with wrapper functions for calling the NCBI eUtilities and PubChem PUG web services. PubChem BioAssays and associated chemical compounds can then be queried and manipulated in a local relational database. Features include chemical structure searching and generation and display of curve fits from stored dose–response experiments, something that is not yet available within PubChem itself. The aim is to provide researchers with a fast, consistent, queryable local resource from which to manipulate PubChem BioAssays in a database agnostic manner. It is not intended as an end user tool but to provide a platform for further automation and tools development. Availability: http://code.google.com/p/pubchemdb Contact: southern@scripps.edu PMID:21216779

  6. Getting the Most out of PubChem for Virtual Screening

    PubMed Central

    Kim, Sunghwan

    2016-01-01

    Introduction With the emergence of the “big data” era, the biomedical research community has great interest in exploiting publicly available chemical information for drug discovery. PubChem is an example of public databases that provide a large amount of chemical information free of charge. Areas covered This article provides an overview of how PubChem’s data, tools, and services can be used for virtual screening and reviews recent publications that discuss important aspects of exploiting PubChem for drug discovery. Expert opinion PubChem offers comprehensive chemical information useful for drug discovery. It also provides multiple programmatic access routes, which are essential to build automated virtual screening pipelines that exploit PubChem data. In addition, PubChemRDF allows users to download PubChem data and load them into a local computing facility, facilitating data integration between PubChem and other resources. PubChem resources have been used in many studies for developing bioactivity and toxicity prediction models, discovering polypharmacologic (multi-target) ligands, and identifying new macromolecule targets of compounds (for drug-repurposing or off-target side effect prediction). These studies demonstrate the usefulness of PubChem as a key resource for computer-aided drug discovery and related area. PMID:27454129

  7. PubChem applications in drug discovery: a bibliometric analysis

    PubMed Central

    Cheng, Tiejun; Pan, Yongmei; Hao, Ming; Wang, Yanli; Bryant, Stephen H.

    2014-01-01

    A bibliometric analysis of PubChem applications is presented by reviewing 1132 research articles. The massive volume of chemical structure and bioactivity data in PubChem and its online services has been used globally in various fields including chemical biology, medicinal chemistry and informatics research. PubChem supports drug discovery in many aspects such as lead identification and optimization, compound–target profiling, polypharmacology studies and unknown chemical identity elucidation. PubChem has also become a valuable resource for developing secondary databases, informatics tools and web services. The growing PubChem resource with its public availability offers support and great opportunities for the interrogation of pharmacological mechanisms and the genetic basis of diseases, which are vital for drug innovation and repurposing. PMID:25168772

  8. Chemical Demilitarization Assembled Chemical Weapons Alternatives (Chem Demil-ACWA)

    DTIC Science & Technology

    2015-12-01

    Weapons Alternatives (Chem Demil-ACWA) is performing a portion of the chemical warfare materiel elimination mission. In 1996, Congress and the...Selected Acquisition Report (SAR) RCS: DD-A&T(Q&A)823-243 Chemical Demilitarization-Assembled Chemical Weapons Alternatives (Chem Demil-ACWA) As...Date Assigned: December 19, 2010 Program Information Program Name Chemical Demilitarization-Assembled Chemical Weapons Alternatives (Chem Demil

  9. PubChem3D: conformer ensemble accuracy

    PubMed Central

    2013-01-01

    Background PubChem is a free and publicly available resource containing substance descriptions and their associated biological activity information. PubChem3D is an extension to PubChem containing computationally-derived three-dimensional (3-D) structures of small molecules. All the tools and services that are a part of PubChem3D rely upon the quality of the 3-D conformer models. Construction of the conformer models currently available in PubChem3D involves a clustering stage to sample the conformational space spanned by the molecule. While this stage allows one to downsize the conformer models to more manageable size, it may result in a loss of the ability to reproduce experimentally determined “bioactive” conformations, for example, found for PDB ligands. This study examines the extent of this accuracy loss and considers its effect on the 3-D similarity analysis of molecules. Results The conformer models consisting of up to 100,000 conformers per compound were generated for 47,123 small molecules whose structures were experimentally determined, and the conformers in each conformer model were clustered to reduce the size of the conformer model to a maximum of 500 conformers per molecule. The accuracy of the conformer models before and after clustering was evaluated using five different measures: root-mean-square distance (RMSD), shape-optimized shape-Tanimoto (STST-opt) and combo-Tanimoto (ComboTST-opt), and color-optimized color-Tanimoto (CTCT-opt) and combo-Tanimoto (ComboTCT-opt). On average, the effect of clustering decreased the conformer model accuracy, increasing the conformer ensemble’s RMSD to the bioactive conformer (by 0.18 ± 0.12 Å), and decreasing the STST-opt, ComboTST-opt, CTCT-opt, and ComboTCT-opt scores (by 0.04 ± 0.03, 0.16 ± 0.09, 0.09 ± 0.05, and 0.15 ± 0.09, respectively). Conclusion This study shows the RMSD accuracy performance of the PubChem3D conformer models is operating as designed. In addition, the effect of PubChem3D

  10. Whole Plant Utilization of Sunflowers as a Renewable Source of Strategic Materials (Rubber).

    DTIC Science & Technology

    1985-04-14

    This is an important aspect in getting a strategic crop started without incurring large government subsidies . The extracted residue of sunflowers...Ontario, Canada by Minshall (1957) contained only 0.26% rubber. This could be evidence of environmental effects or of genetic variation within species...plants of Canada. Canada Dept. of Agric ., Ottawa, Ontario. Morgan, R.P. and E.B. Shultz, Jr. 1981. Fuels and chemicals from novel seed oils. Chem. Eng

  11. ChemOkey: A Game to Reinforce Nomenclature

    ERIC Educational Resources Information Center

    Kavak, Nusret

    2012-01-01

    Learning the symbolic language of chemistry is a difficult task that can be frustrating for students. This article introduces a game, ChemOkey, that can help students learn the names and symbols of common ions and their compounds in a fun environment. ChemOkey, a game similar to Rummikub, is played with a set of 106 plastic or wooden tiles. The…

  12. ChemPreview: an augmented reality-based molecular interface.

    PubMed

    Zheng, Min; Waller, Mark P

    2017-05-01

    Human computer interfaces make computational science more comprehensible and impactful. Complex 3D structures such as proteins or DNA are magnified by digital representations and displayed on two-dimensional monitors. Augmented reality has recently opened another door to access the virtual three-dimensional world. Herein, we present an augmented reality application called ChemPreview with the potential to manipulate bio-molecular structures at an atomistic level. ChemPreview is available at https://github.com/wallerlab/chem-preview/releases, and is built on top of the Meta 1 platform https://www.metavision.com/. ChemPreview can be used to interact with a protein in an intuitive way using natural hand gestures, thereby making it appealing to computational chemists or structural biologists. The ability to manipulate atoms in real world could eventually provide new and more efficient ways of extracting structural knowledge, or designing new molecules in silico. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. radEq Add-On Module for CFD Solver Loci-CHEM

    NASA Technical Reports Server (NTRS)

    McCloud, Peter

    2013-01-01

    Loci-CHEM to be applied to flow velocities where surface radiation due to heating from compression and friction becomes significant. The module adds a radiation equilibrium boundary condition to the computational fluid dynamics (CFD) code to produce accurate results. The module expanded the upper limit for accurate CFD solutions of Loci-CHEM from Mach 4 to Mach 10 based on Space Shuttle Orbiter Re-Entry trajectories. Loci-CHEM already has a very promising architecture and performance, but absence of radiation equilibrium boundary condition limited the application of Loci-CHEM to below Mach 4. The immediate advantage of the add-on module is that it allows Loci-CHEM to work with supersonic flows up to Mach 10. This transformed Loci-CHEM from a rocket engine- heritage CFD code with general subsonic and low-supersonic applications, to an aeroheating code with hypersonic applications. The follow-on advantage of the module is that it is a building block for additional add-on modules that will solve for the heating generated at Mach numbers higher than 10.

  14. Engaging Organic Chemistry Students Using ChemDraw for iPad

    ERIC Educational Resources Information Center

    Morsch, Layne A.; Lewis, Michael

    2015-01-01

    Drawing structures, mechanisms, and syntheses is a vital part of success in organic chemistry courses. ChemDraw for iPad has been used to increase classroom experiences in the preparation of high quality chemical drawings. The embedded Flick-to-Share allows for simple, real-time exchange of ChemDraw documents. ChemDraw for iPad also allows…

  15. Chem-E-Car Downunder.

    ERIC Educational Resources Information Center

    Rhodes, Martin

    2002-01-01

    Presents the Chem-E-Car competition in which students build a small car powered by a chemical reaction. Focuses on a controlled chemical reaction in which the car travels a required specific distance and stops. Requires participants to prepare poster presentations. (YDS)

  16. Searching Online Chemical Data Repositories via the ChemAgora Portal.

    PubMed

    Zanzi, Antonella; Wittwehr, Clemens

    2017-12-26

    ChemAgora, a web application designed and developed in the context of the "Data Infrastructure for Chemical Safety Assessment" (diXa) project, provides search capabilities to chemical data from resources available online, enabling users to cross-reference their search results with both regulatory chemical information and public chemical databases. ChemAgora, through an on-the-fly search, informs whether a chemical is known or not in each of the external data sources and provides clikable links leading to the third-party web site pages containing the information. The original purpose of the ChemAgora application was to correlate studies stored in the diXa data warehouse with available chemical data. Since the end of the diXa project, ChemAgora has evolved into an independent portal, currently accessible directly through the ChemAgora home page, with improved search capabilities of online data sources.

  17. AEGIS Automated Targeting for the MSL ChemCam Instrument

    NASA Astrophysics Data System (ADS)

    Estlin, T.; Anderson, R. C.; Blaney, D. L.; Bornstein, B.; Burl, M. C.; Castano, R.; Gaines, D.; Judd, M.; Thompson, D. R.; Wiens, R. C.

    2013-12-01

    The Autonomous Exploration for Gathering Increased Science (AEGIS) system enables automated science data collection by a planetary rover. AEGIS has been in use on the Mars Exploration Rover (MER) mission Opportunity rover since 2010 to provide onboard targeting of the MER Panoramic Camera based on scientist-specified objectives. AEGIS is now being applied for use with the Mars Science Laboratory (MSL) mission ChemCam spectrometer. ChemCam uses a Laser Induced Breakdown Spectrometer (LIBS) to analyze the elemental composition of rocks and soil from up to seven meters away. ChemCam's tightly-focused laser beam (350-550 um) enables targeting of very fine-scale terrain features. AEGIS is being applied in two ways to help ChemCam collect valuable science data. The first application is to enable automated targeting of ChemCam during or after or in the middle of long drives. The majority of ChemCam measurements are collected by allowing the science team to select specific targets in rover images. However this requires the rover to stay in the same area while images are downlinked, analyzed for targets, and new commands uplinked. The only data that can be acquired without this communication cycle is via blind targeting, where measurements are often of soil patches vs. instead of more valuable targets such as rocks with specific properties. AEGIS is being applied to automatically analyze images onboard and select targets for ChemCam analysis. This approach allows the rover to autonomously select and sequence targeted measurements in an opportunistic fashion at different points along the rover's drive path. Rock targets can be prioritized for measurement based on various geologically relevant features, including size, shape and albedo. A second application is to enable intelligent pointing refinement of ChemCam when acquiring data of small targets, such as veins or concretions that are only a few millimeters wide. Due to backlash and other pointing challenges, it can often

  18. Engineering Analysis in the Chem-E-Car Competition

    ERIC Educational Resources Information Center

    Lewis, Randy S.; Moshfeghian, Aliakbar; Madihally, Sundararajan V.

    2006-01-01

    The AIChE Chem-E-Car competition provides students an opportunity to demonstrate their design and teamwork skills. Engineering analysis is not required at the national competition and is often not applied. This work describes an engineering analysis of a Chem-E-Car to predict the distance traveled by the car. Engineering analysis is advantageous…

  19. The CHEM Study Story.

    ERIC Educational Resources Information Center

    Merrill, Richard J.; Ridgway, David W.

    The history of the planning, funding, preparation of preliminary materials, teacher preparation, trial teaching, evaluation, revision and final publication of the CHEM Study materials is presented. The anecdotal account points out the difficulties encountered, the solutions found and the pitfalls avoided so that the experience gained may be useful…

  20. The Another Assimilation System for WRF-Chem (AAS4WRF): a new mass-conserving emissions pre-processor for WRF-Chem regional modelling

    NASA Astrophysics Data System (ADS)

    Vara Vela, A. L.; Muñoz, A.; Lomas, A., Sr.; González, C. M.; Calderon, M. G.; Andrade, M. D. F.

    2017-12-01

    The Weather Research and Forecasting with Chemistry (WRF-Chem) community model have been widely used for the study of pollutants transport, formation of secondary pollutants, as well as for the assessment of air quality policies implementation. A key factor to improve the WRF-Chem air quality simulations over urban areas is the representation of anthropogenic emission sources. There are several tools that are available to assist users in creating their own emissions based on global emissions information (e.g. anthro_emiss, prep_chem_src); however, there is no single tool that will construct local emissions input datasets for any particular domain at this time. Because the official emissions pre-processor (emiss_v03) is designed to work with domains located over North America, this work presents the Another Assimilation System for WRF-Chem (AAS4WRF), a ncl based mass-conserving emissions pre-processor designed to create WRF-Chem ready emissions files from local inventories on a lat/lon projection. AAS4WRF is appropriate to scale emission rates from both surface and elevated sources, providing the users an alternative way to assimilate their emissions to WRF-Chem. Since it was successfully tested for the first time for the city of Lima, Peru in 2014 (managed by SENAMHI, the National Weather Service of the country), several studies on air quality modelling have applied this utility to convert their emissions to those required for WRF-Chem. Two case studies performed in the metropolitan areas of Sao Paulo and Manizales in Brazil and Colombia, respectively, are here presented in order to analyse the influence of using local or global emission inventories in the representation of regulated air pollutants such as O3 and PM2.5. Although AAS4WRF works with local emissions information at the moment, further work is being conducted to make it compatible with global/regional emissions data file format. The tool is freely available upon request to the corresponding author.

  1. ChemRad Sample Form Instructions

    EPA Pesticide Factsheets

    These instructons are intended to assist registered users of the EPA Region 8 Drinking Water Watch website who would like to create ChemRad Sample Forms for monitoring that is required during the current year.

  2. Mars Rock Rocknest 3 Imaged by Curiosity ChemCam

    NASA Image and Video Library

    2012-11-26

    This view of a rock called Rocknest 3 combines two images taken by the Chemistry and Camera ChemCam instrument on the NASA Mars rover Curiosity and indicates five spots where ChemCam had hit the rock with laser pulses to check its composition.

  3. Japan Report, Science and Technology.

    DTIC Science & Technology

    1986-12-15

    Sakamoto, "Glutathione," KODANSHA SCIENTIFIC (1985). 2. T. Tochikura, et al., J. FERMENT . TECHNOL., 45, 511 (1967). 3. Ibid., 46, 957 (1968). 4. S...Watanabe, et al., AGRIC. BIOL. CHEM., 36, 2265 (1972). 5. T. Tochikura, et al., J. FERMENT . TECHNOL., 48, 763 (1970). 6. T. Tachiki, et al., J. GEN. APPL...Tachiki and T. Tochikura, Fermentation and Industry, 41, 736, 1983). 13. K. Murata, J. Kato, and I. Senhata, Ibid., 39, 900 (1981). 14. Y. Isokazu

  4. AutoClickChem: click chemistry in silico.

    PubMed

    Durrant, Jacob D; McCammon, J Andrew

    2012-01-01

    Academic researchers and many in industry often lack the financial resources available to scientists working in "big pharma." High costs include those associated with high-throughput screening and chemical synthesis. In order to address these challenges, many researchers have in part turned to alternate methodologies. Virtual screening, for example, often substitutes for high-throughput screening, and click chemistry ensures that chemical synthesis is fast, cheap, and comparatively easy. Though both in silico screening and click chemistry seek to make drug discovery more feasible, it is not yet routine to couple these two methodologies. We here present a novel computer algorithm, called AutoClickChem, capable of performing many click-chemistry reactions in silico. AutoClickChem can be used to produce large combinatorial libraries of compound models for use in virtual screens. As the compounds of these libraries are constructed according to the reactions of click chemistry, they can be easily synthesized for subsequent testing in biochemical assays. Additionally, in silico modeling of click-chemistry products may prove useful in rational drug design and drug optimization. AutoClickChem is based on the pymolecule toolbox, a framework that may facilitate the development of future python-based programs that require the manipulation of molecular models. Both the pymolecule toolbox and AutoClickChem are released under the GNU General Public License version 3 and are available for download from http://autoclickchem.ucsd.edu.

  5. AutoClickChem: Click Chemistry in Silico

    PubMed Central

    Durrant, Jacob D.; McCammon, J. Andrew

    2012-01-01

    Academic researchers and many in industry often lack the financial resources available to scientists working in “big pharma.” High costs include those associated with high-throughput screening and chemical synthesis. In order to address these challenges, many researchers have in part turned to alternate methodologies. Virtual screening, for example, often substitutes for high-throughput screening, and click chemistry ensures that chemical synthesis is fast, cheap, and comparatively easy. Though both in silico screening and click chemistry seek to make drug discovery more feasible, it is not yet routine to couple these two methodologies. We here present a novel computer algorithm, called AutoClickChem, capable of performing many click-chemistry reactions in silico. AutoClickChem can be used to produce large combinatorial libraries of compound models for use in virtual screens. As the compounds of these libraries are constructed according to the reactions of click chemistry, they can be easily synthesized for subsequent testing in biochemical assays. Additionally, in silico modeling of click-chemistry products may prove useful in rational drug design and drug optimization. AutoClickChem is based on the pymolecule toolbox, a framework that may facilitate the development of future python-based programs that require the manipulation of molecular models. Both the pymolecule toolbox and AutoClickChem are released under the GNU General Public License version 3 and are available for download from http://autoclickchem.ucsd.edu. PMID:22438795

  6. ConfChem Conference on Flipped Classroom: Spring 2014 ConfChem Virtual Poster Session

    ERIC Educational Resources Information Center

    Belford, Robert E.; Stoltzfus, Matthew; Houseknecht, Justin B.

    2015-01-01

    This communication describes the virtual poster session of the Flipped Classroom online ConfChem conference that was hosted by the ACS CHED Committee on Computers in Chemical Education (CCCE) from May 9 to June 12, 2014. During the conference's online discussions, it became evident that multiple participants who were not presenting papers had been…

  7. Curiosity's ChemCam Checks 'Christmas Cove' Colors

    NASA Image and Video Library

    2017-11-01

    The Chemistry and Camera (ChemCam) instrument on NASA's Curiosity Mars rover examined a freshly brushed area on target rock "Christmas Cove" and found spectral evidence of hematite, an iron-oxide mineral. ChemCam sometimes zaps rocks with a laser, but can also be used, as in this case, in a "passive" mode. In this type of investigation, the instrument's telescope delivers to spectrometers the sunlight reflected from a small target point. The upper-left inset of this graphic is an image from ChemCam's Remote Micro-Imager with five labeled points that the instrument analyzed. The image covers an area about 2 inches (5 centimeters) wide, and the bright lines are fractures in the rock filled with calcium sulfate minerals. The five charted lines of the graphic correspond to those five points and show the spectrometer measurements of brightness at thousands of different wavelengths, from 400 nanometers (at the violet end of the visible-light spectrum) to 840 nanometers (in near-infrared). Sections of the spectrum measurements that are helpful for identifying hematite are annotated. These include a dip around 535 nanometers, the green-light portion of the spectrum at which fine-grained hematite tends to absorb more light and reflect less compared to other parts of the spectrum. That same green-absorbing characteristic of the hematite makes it appear purplish when imaged through special filters of Curiosity's Mast Camera and even in usual color images. The spectra also show maximum reflectance values near 750 nanometers, followed by a steep decrease in the spectral slope toward 840 nanometers, both of which are consistent with hematite. This ChemCam examination of Christmas Cove was part of an experiment to determine whether the rock had evidence of hematite under a tan coating of dust. The target area was brushed with Curiosity's Dust Removal Tool prior to these ChemCam passive observations on Sept. 17, 2017, during the 1,819th Martian day, or sol, of Curiosity's work on

  8. ChemCam Targeted Science at Gale Crater

    NASA Astrophysics Data System (ADS)

    Wiens, R. C.; Blaney, D. L.; Clark, B. C.; Bridges, N. T.; Clegg, S. M.; Maurice, S.; Newsom, H. E.; Vaniman, D. T.; Herkenhoff, K. E.; Ollila, A. M.; Gasnault, O.; Pinet, P. C.; Dromart, G.; Barraclough, B. L.; Lasue, J.

    2011-12-01

    The MSL rover, Curiosity, uses a novel remote-sensing instrument, ChemCam, which combines laser-induced breakdown spectroscopy (LIBS) with a high resolution remote micro-imager (RMI). ChemCam uses a focused, pulsed laser beam at targets up to 7 m away to excite a light-emitting plasma. Spectral analysis identifies elements present and provides rapid semi-quantitative analyses. Repeated laser pulses remove dust and weathering coatings from rock samples to depths >0.5 mm and ~0.4 mm in diameter. The RMI, with ~20x20 mrad field of view, provides a broad-band image with 100 μm resolution. LIBS yields abundances of H, Li, Be, B, C, N, O, F, Na, Mg, Al, Si, P, Cl, K, Ca, Ti, V, Cr, Fe, Ni, Zr, Rb, Sr, As, Ba, and Pb. Interference from atmospheric constituents raises the detection limits of C, N, and O (e.g., >2% wt for C). LIBS is very sensitive to alkali and alkali earth elements, with some detection limits to ~1 ppm at close range. Conversely, LIBS is insensitive to F, Cl, S, P, and N, with detection limits of several wt. %. Pointing accuracy is ~3 mrad, however relative pointing accuracy is better, so line scans and rasters will enable analyses of targeted features to ~1 mm. At Gale Crater, determination of elements not previously analyzed in-situ, i.e., H, Li, Rb, Sr, and Ba, along with other elements will constrain aqueous, hydrothermal and vapor geochemical transport processes. Initial analyses after landing will characterize air fall dust and weathering coatings on local rocks, and profile the soil and surfacial materials including bedforms to investigate compositional differences in near-surface layers. Targets within the landing ellipse include fan and inverted channel deposits derived from the crater rim, which may contain alteration minerals produced by impact hydrothermal processes. Enigmatic deposits with bright fracture fill could represent lake sediments modified by injection of deposits from groundwater. During the drive to the Gale mound, ChemCam will

  9. NARSTO EPA SS NEW YORK AIR CHEM PM MET DATA

    Atmospheric Science Data Center

    2018-04-09

    NARSTO EPA SS NEW YORK AIR CHEM PM MET DATA Project Title:  NARSTO ... Nitrogen Oxides Ozone Surface Winds Air Temperature Humidity Solar Irradiance Particulate Matter ... Data Guide Documents:  New York Air Chem Guide CPM Summary Report  (PDF) Nitrate ...

  10. Hazardous Waste Cleanup: Cycle Chem Incorporated in Elizabeth, New Jersey

    EPA Pesticide Factsheets

    Cycle Chem is located at 217 South First Street in Elizabeth, New Jersey. Cycle Chem recovers spent solvents and treats both hazardous and non-hazardous wastes in containers and tanks. The site comprises two acres in an industrial area, surrounded by

  11. Curiosity ChemCam Removes Dust

    NASA Image and Video Library

    2013-04-08

    This pair of images taken a few minutes apart show how laser firing by NASA Mars rover Curiosity removes dust from the surface of a rock. The images were taken by the remote micro-imager camera in the laser-firing Chemistry and Camera ChemCam.

  12. EarthChem: International Collaboration for Solid Earth Geochemistry in Geoinformatics

    NASA Astrophysics Data System (ADS)

    Walker, J. D.; Lehnert, K. A.; Hofmann, A. W.; Sarbas, B.; Carlson, R. W.

    2005-12-01

    The current on-line information systems for igneous rock geochemistry - PetDB, GEOROC, and NAVDAT - convincingly demonstrate the value of rigorous scientific data management of geochemical data for research and education. The next generation of hypothesis formulation and testing can be vastly facilitated by enhancing these electronic resources through integration of available datasets, expansion of data coverage in location, time, and tectonic setting, timely updates with new data, and through intuitive and efficient access and data analysis tools for the broader geosciences community. PetDB, GEOROC, and NAVDAT have therefore formed the EarthChem consortium (www.earthchem.org) as a international collaborative effort to address these needs and serve the larger earth science community by facilitating the compilation, communication, serving, and visualization of geochemical data, and their integration with other geological, geochronological, geophysical, and geodetic information to maximize their scientific application. We report on the status of and future plans for EarthChem activities. EarthChem's development plan includes: (1) expanding the functionality of the web portal to become a `one-stop shop for geochemical data' with search capability across databases, standardized and integrated data output, generally applicable tools for data quality assessment, and data analysis/visualization including plotting methods and an information-rich map interface; and (2) expanding data holdings by generating new datasets as identified and prioritized through community outreach, and facilitating data contributions from the community by offering web-based data submission capability and technical assistance for design, implementation, and population of new databases and their integration with all EarthChem data holdings. Such federated databases and datasets will retain their identity within the EarthChem system. We also plan on working with publishers to ease the assimilation

  13. Chem-Braze Abradable Seal Attachment to Aircraft Gas Turbine Compressor Components.

    DTIC Science & Technology

    1982-01-01

    seals to compressor blade tip-shrouds using the im- proved Chem-Braze system compared to attachment with gold-nickel braze. The Chem-Braze system has been...used successfully to bond abradable seals to titanium ’ cobalt, nickel and iron base alloys; however, attempts to use Chem-Braze to bond seals to...attaching FELTMETALO seals to steel, titanium , and nickel-based alloys, and ICB bonding procedures were investigated for attaching seals to selected

  14. ChemBank: a small-molecule screening and cheminformatics resource database.

    PubMed

    Seiler, Kathleen Petri; George, Gregory A; Happ, Mary Pat; Bodycombe, Nicole E; Carrinski, Hyman A; Norton, Stephanie; Brudz, Steve; Sullivan, John P; Muhlich, Jeremy; Serrano, Martin; Ferraiolo, Paul; Tolliday, Nicola J; Schreiber, Stuart L; Clemons, Paul A

    2008-01-01

    ChemBank (http://chembank.broad.harvard.edu/) is a public, web-based informatics environment developed through a collaboration between the Chemical Biology Program and Platform at the Broad Institute of Harvard and MIT. This knowledge environment includes freely available data derived from small molecules and small-molecule screens and resources for studying these data. ChemBank is unique among small-molecule databases in its dedication to the storage of raw screening data, its rigorous definition of screening experiments in terms of statistical hypothesis testing, and its metadata-based organization of screening experiments into projects involving collections of related assays. ChemBank stores an increasingly varied set of measurements derived from cells and other biological assay systems treated with small molecules. Analysis tools are available and are continuously being developed that allow the relationships between small molecules, cell measurements, and cell states to be studied. Currently, ChemBank stores information on hundreds of thousands of small molecules and hundreds of biomedically relevant assays that have been performed at the Broad Institute by collaborators from the worldwide research community. The goal of ChemBank is to provide life scientists unfettered access to biomedically relevant data and tools heretofore available primarily in the private sector.

  15. CHEM-Based Self-Deploying Spacecraft Radar Antennas

    NASA Technical Reports Server (NTRS)

    Sokolowski, Witold; Huang, John; Ghaffarian, Reza

    2004-01-01

    A document proposes self-deploying spacecraft radar antennas based on cold hibernated elastic memory (CHEM) structures. Described in a number of prior NASA Tech Briefs articles, the CHEM concept is one of utilizing open-cell shape-memory-polymer (SMP) foams to make lightweight structures that can be compressed for storage and can later be expanded, then rigidified for use. A CHEM-based antenna according to the proposal would comprise three layers of microstrip patches and transmission lines interspersed with two flat layers of SMP foam, which would serve as both dielectric spacers and as means of deployment. The SMP foam layers would be fabricated at full size at a temperature below the SMP glass-transition temperature (Tg). The layers would be assembled into a unitary structure, which, at temperature above Tg, would be compacted to much smaller thickness, then rolled up for storage. Next, the structure would be cooled to below Tg and kept there during launch. Upon reaching the assigned position in outer space, the structure would be heated above Tg to make it rebound to its original size and shape. The structure as thus deployed would then be rigidified by natural cooling to below Tg

  16. Antioxidant capacity of BO-653, 2,3-dihydro-5-hydroxy-4,6-di-tert-butyl-2,2-dipentylbenzofuran, and uric acid as evaluated by ORAC method and inhibition of lipid peroxidation.

    PubMed

    Niki, Etsuo; Fukuhara, Akiko; Omata, Yo; Saito, Yoshiro; Yoshida, Yasukazu

    2008-04-01

    The role of radical-scavenging antioxidant against oxidative stress has received much attention. The antioxidant capacity has been assessed by various methods. Above all, oxygen radical absorbance capacity (ORAC) has been frequently employed [Prior et.al., J. Agric. Food Chem.2005, 53, 4290]. In the present study, the antioxidant capacity of 2,3-dihydro-5-hydroxy-4,6-di-tert-butyl-2,2-dipentylbenzofuran (BO-653) and uric acid was assessed by ORAC method using pyranine as a reference probe and compared with that against lipid peroxidation of human plasma. It was found that BO-653 was assessed to be much less potent than uric acid by ORAC method, whereas BO-653 exerted much higher antioxidant activity than uric acid against plasma lipid peroxidation. The reason for such discrepancy is discussed. The results suggest that ORAC method is suitable for the assessment of free radical scavenging capacity, but not for the assessment of antioxidant capacity against lipid peroxidation in plasma.

  17. "CHEM"opera for Chemistry Education

    ERIC Educational Resources Information Center

    Chung, Yong Hee

    2013-01-01

    "CHEM"opera is an opera blended with demonstrations of chemical reactions. It has been produced and performed twice by chemistry undergraduate students at Hallym University in South Korea. It aims to demonstrate interesting chemical reactions to chemistry students, children and the public and to facilitate their understanding of the role…

  18. Development of the EarthChem Geochronology and Thermochronology database: Collaboration of the EarthChem and EARTHTIME efforts

    NASA Astrophysics Data System (ADS)

    Walker, J. D.; Ash, J. M.; Bowring, J.; Bowring, S. A.; Deino, A. L.; Kislitsyn, R.; Koppers, A. A.

    2009-12-01

    One of the most onerous tasks in rigorous development of data reporting and databases for geochronological and thermochronological studies is to fully capture all of the metadata needed to completely document both the analytical work as well as the interpretation effort. This information is available in the data reduction programs used by researchers, but has proven difficult to harvest into either publications or databases. For this reason, the EarthChem and EARTHTIME efforts are collaborating to foster the next generation of data management and discovery for age information by integrating data reporting with data reduction. EarthChem is a community-driven effort to facilitate the discovery, access, and preservation of geochemical data of all types and to support research and enable new and better science. EARTHTIME is also a community-initiated project whose aim is to foster the next generation of high-precision geochronology and thermochoronology. In addition, collaboration with the CRONUS effort for cosmogenic radionuclides is in progress. EarthChem workers have met with groups working on the Ar-Ar, U-Pb, and (U-Th)/He systems to establish data reporting requirements as well as XML schemas to be used for transferring data from reduction programs to database. At present, we have prototype systems working for the U-Pb_Redux, ArArCalc, MassSpec, and Helios programs. In each program, the user can select to upload data and metadata to the GEOCHRON system hosted at EarthChem. There are two additional requirements for upload. The first is having a unique identifier (IGSN) obtained either manually or via web services contained within the reduction program from the SESAR system. The second is that the user selects whether the sample is to be available for discovery (public) or remain hidden (private). Search for data at the GEOCHRON portal can be done using age, method, mineral, or location parameters. Data can be downloaded in the full XML format for ingestion back

  19. Evaluation of Chem-Crete : final report.

    DOT National Transportation Integrated Search

    1982-01-01

    Two test sections, one on new construction and the other on a maintenance resurfacing project, were installed in the fall of 1980 to evaluate the proprietary product Chem-Crete. Laboratory tests and dynaflect and density measurements were performed o...

  20. DPubChem: a web tool for QSAR modeling and high-throughput virtual screening.

    PubMed

    Soufan, Othman; Ba-Alawi, Wail; Magana-Mora, Arturo; Essack, Magbubah; Bajic, Vladimir B

    2018-06-14

    High-throughput screening (HTS) performs the experimental testing of a large number of chemical compounds aiming to identify those active in the considered assay. Alternatively, faster and cheaper methods of large-scale virtual screening are performed computationally through quantitative structure-activity relationship (QSAR) models. However, the vast amount of available HTS heterogeneous data and the imbalanced ratio of active to inactive compounds in an assay make this a challenging problem. Although different QSAR models have been proposed, they have certain limitations, e.g., high false positive rates, complicated user interface, and limited utilization options. Therefore, we developed DPubChem, a novel web tool for deriving QSAR models that implement the state-of-the-art machine-learning techniques to enhance the precision of the models and enable efficient analyses of experiments from PubChem BioAssay database. DPubChem also has a simple interface that provides various options to users. DPubChem predicted active compounds for 300 datasets with an average geometric mean and F 1 score of 76.68% and 76.53%, respectively. Furthermore, DPubChem builds interaction networks that highlight novel predicted links between chemical compounds and biological assays. Using such a network, DPubChem successfully suggested a novel drug for the Niemann-Pick type C disease. DPubChem is freely available at www.cbrc.kaust.edu.sa/dpubchem .

  1. Dust Detection by Curiosity ChemCam

    NASA Image and Video Library

    2013-04-08

    The ChemCam instrument on NASA Curiosity Mars rover fired its laser 50 times at its onboard graphite target showing spectral measurements from the first shot, which hit dust on the target, compared to spectral measurements of from the 50th shot.

  2. Chem/bio sensing with non-classical light and integrated photonics.

    PubMed

    Haas, J; Schwartz, M; Rengstl, U; Jetter, M; Michler, P; Mizaikoff, B

    2018-01-29

    Modern quantum technology currently experiences extensive advances in applicability in communications, cryptography, computing, metrology and lithography. Harnessing this technology platform for chem/bio sensing scenarios is an appealing opportunity enabling ultra-sensitive detection schemes. This is further facilliated by the progress in fabrication, miniaturization and integration of visible and infrared quantum photonics. Especially, the combination of efficient single-photon sources together with waveguiding/sensing structures, serving as active optical transducer, as well as advanced detector materials is promising integrated quantum photonic chem/bio sensors. Besides the intrinsic molecular selectivity and non-destructive character of visible and infrared light based sensing schemes, chem/bio sensors taking advantage of non-classical light sources promise sensitivities beyond the standard quantum limit. In the present review, recent achievements towards on-chip chem/bio quantum photonic sensing platforms based on N00N states are discussed along with appropriate recognition chemistries, facilitating the detection of relevant (bio)analytes at ultra-trace concentration levels. After evaluating recent developments in this field, a perspective for a potentially promising sensor testbed is discussed for reaching integrated quantum sensing with two fiber-coupled GaAs chips together with semiconductor quantum dots serving as single-photon sources.

  3. Distributed chemical computing using ChemStar: an open source java remote method invocation architecture applied to large scale molecular data from PubChem.

    PubMed

    Karthikeyan, M; Krishnan, S; Pandey, Anil Kumar; Bender, Andreas; Tropsha, Alexander

    2008-04-01

    We present the application of a Java remote method invocation (RMI) based open source architecture to distributed chemical computing. This architecture was previously employed for distributed data harvesting of chemical information from the Internet via the Google application programming interface (API; ChemXtreme). Due to its open source character and its flexibility, the underlying server/client framework can be quickly adopted to virtually every computational task that can be parallelized. Here, we present the server/client communication framework as well as an application to distributed computing of chemical properties on a large scale (currently the size of PubChem; about 18 million compounds), using both the Marvin toolkit as well as the open source JOELib package. As an application, for this set of compounds, the agreement of log P and TPSA between the packages was compared. Outliers were found to be mostly non-druglike compounds and differences could usually be explained by differences in the underlying algorithms. ChemStar is the first open source distributed chemical computing environment built on Java RMI, which is also easily adaptable to user demands due to its "plug-in architecture". The complete source codes as well as calculated properties along with links to PubChem resources are available on the Internet via a graphical user interface at http://moltable.ncl.res.in/chemstar/.

  4. ChemCam Science Objectives for the Mars Science Laboratory (MSL) Rover

    NASA Technical Reports Server (NTRS)

    Wiens, R.; Maurice, S.; Bridges, N.; Clark, B.; Cremers, D.; Herkenhoff, K.; Kirkland, L.; Mangold, N.; Manhes, G.; Mauchien, P.

    2005-01-01

    ChemCam consists of two remote sensing instruments. One, a Laser-Induced Breakdown Spectroscopy (LIBS) instrument provides rapid elemental composition data on rocks and soils within 13 m of the rover. By using laser pulses, it can remove dust or profile through weathering layers remotely. The other instrument, the Remote Micro-Imager (RMI), provides the highest resolution images between 2 m and infinity. At approximately 80 Rad field of view, its resolution exceeds that of MER Pancam by at least a factor of four. The ChemCam instruments are described in a companion paper by Maurice et al. [1]. Here we present the science objectives for the ChemCam instrument package.

  5. ChemCam Science Objectives for the Mars Science Laboratory (MSL) Rover

    NASA Technical Reports Server (NTRS)

    Wiens, R.; Maurice, S.; Bridges, N.; Clark, B.; Cremers, D.; Herkenhoff, K.; Kirkland, L.; Mangold, N.; Manhes, G.; Mauchien, P.

    2005-01-01

    ChemCam consists of two remote sensing instruments. One, a Laser-Induced Breakdown Spectroscopy (LIBS) instrument provides rapid elemental composition data on rocks and soils within 13 m of the rover. By using laser pulses, it can remove dust or profile through weathering layers remotely. The other instrument, the Remote Micro-Imager (RMI), provides the highest resolution images between 2 m and infinity. At approximately 80 Rad field of view, its resolution exceeds that of MER Pancam by at least a factor of four. The ChemCam instruments are described in a companion paper by Maurice et al. Here we present the science objectives for the ChemCam instrument package.

  6. Consequences of ChemR23 Heteromerization with the Chemokine Receptors CXCR4 and CCR7

    PubMed Central

    de Poorter, Cédric; Baertsoen, Kevin; Lannoy, Vincent; Parmentier, Marc; Springael, Jean-Yves

    2013-01-01

    Recent studies have shown that heteromerization of the chemokine receptors CCR2, CCR5 and CXCR4 is associated to negative binding cooperativity. In the present study, we build on these previous results, and investigate the consequences of chemokine receptor heteromerization with ChemR23, the receptor of chemerin, a leukocyte chemoattractant protein structurally unrelated to chemokines. We show, using BRET and HTRF assays, that ChemR23 forms homomers, and provide data suggesting that ChemR23 also forms heteromers with the chemokine receptors CCR7 and CXCR4. As previously described for other chemokine receptor heteromers, negative binding cooperativity was detected between ChemR23 and chemokine receptors, i.e. the ligands of one receptor competed for the binding of a specific tracer of the other. We also showed, using mouse bone marrow-derived dendritic cells prepared from wild-type and ChemR23 knockout mice, that ChemR23-specific ligands cross-inhibited CXCL12 binding on CXCR4 in a ChemR23-dependent manner, supporting the relevance of the ChemR23/CXCR4 interaction in native leukocytes. Finally, and in contrast to the situation encountered for other previously characterized CXCR4 heteromers, we showed that the CXCR4-specific antagonist AMD3100 did not cross-inhibit chemerin binding in cells co-expressing ChemR23 and CXCR4, demonstrating that cross-regulation by AMD3100 depends on the nature of receptor partners with which CXCR4 is co-expressed. PMID:23469143

  7. Consequences of ChemR23 heteromerization with the chemokine receptors CXCR4 and CCR7.

    PubMed

    de Poorter, Cédric; Baertsoen, Kevin; Lannoy, Vincent; Parmentier, Marc; Springael, Jean-Yves

    2013-01-01

    Recent studies have shown that heteromerization of the chemokine receptors CCR2, CCR5 and CXCR4 is associated to negative binding cooperativity. In the present study, we build on these previous results, and investigate the consequences of chemokine receptor heteromerization with ChemR23, the receptor of chemerin, a leukocyte chemoattractant protein structurally unrelated to chemokines. We show, using BRET and HTRF assays, that ChemR23 forms homomers, and provide data suggesting that ChemR23 also forms heteromers with the chemokine receptors CCR7 and CXCR4. As previously described for other chemokine receptor heteromers, negative binding cooperativity was detected between ChemR23 and chemokine receptors, i.e. the ligands of one receptor competed for the binding of a specific tracer of the other. We also showed, using mouse bone marrow-derived dendritic cells prepared from wild-type and ChemR23 knockout mice, that ChemR23-specific ligands cross-inhibited CXCL12 binding on CXCR4 in a ChemR23-dependent manner, supporting the relevance of the ChemR23/CXCR4 interaction in native leukocytes. Finally, and in contrast to the situation encountered for other previously characterized CXCR4 heteromers, we showed that the CXCR4-specific antagonist AMD3100 did not cross-inhibit chemerin binding in cells co-expressing ChemR23 and CXCR4, demonstrating that cross-regulation by AMD3100 depends on the nature of receptor partners with which CXCR4 is co-expressed.

  8. ChemTS: an efficient python library for de novo molecular generation.

    PubMed

    Yang, Xiufeng; Zhang, Jinzhe; Yoshizoe, Kazuki; Terayama, Kei; Tsuda, Koji

    2017-01-01

    Automatic design of organic materials requires black-box optimization in a vast chemical space. In conventional molecular design algorithms, a molecule is built as a combination of predetermined fragments. Recently, deep neural network models such as variational autoencoders and recurrent neural networks (RNNs) are shown to be effective in de novo design of molecules without any predetermined fragments. This paper presents a novel Python library ChemTS that explores the chemical space by combining Monte Carlo tree search and an RNN. In a benchmarking problem of optimizing the octanol-water partition coefficient and synthesizability, our algorithm showed superior efficiency in finding high-scoring molecules. ChemTS is available at https://github.com/tsudalab/ChemTS.

  9. ChemTS: an efficient python library for de novo molecular generation

    PubMed Central

    Yang, Xiufeng; Zhang, Jinzhe; Yoshizoe, Kazuki; Terayama, Kei; Tsuda, Koji

    2017-01-01

    Abstract Automatic design of organic materials requires black-box optimization in a vast chemical space. In conventional molecular design algorithms, a molecule is built as a combination of predetermined fragments. Recently, deep neural network models such as variational autoencoders and recurrent neural networks (RNNs) are shown to be effective in de novo design of molecules without any predetermined fragments. This paper presents a novel Python library ChemTS that explores the chemical space by combining Monte Carlo tree search and an RNN. In a benchmarking problem of optimizing the octanol-water partition coefficient and synthesizability, our algorithm showed superior efficiency in finding high-scoring molecules. ChemTS is available at https://github.com/tsudalab/ChemTS. PMID:29435094

  10. ChemTS: an efficient python library for de novo molecular generation

    NASA Astrophysics Data System (ADS)

    Yang, Xiufeng; Zhang, Jinzhe; Yoshizoe, Kazuki; Terayama, Kei; Tsuda, Koji

    2017-12-01

    Automatic design of organic materials requires black-box optimization in a vast chemical space. In conventional molecular design algorithms, a molecule is built as a combination of predetermined fragments. Recently, deep neural network models such as variational autoencoders and recurrent neural networks (RNNs) are shown to be effective in de novo design of molecules without any predetermined fragments. This paper presents a novel Python library ChemTS that explores the chemical space by combining Monte Carlo tree search and an RNN. In a benchmarking problem of optimizing the octanol-water partition coefficient and synthesizability, our algorithm showed superior efficiency in finding high-scoring molecules. ChemTS is available at https://github.com/tsudalab/ChemTS.

  11. Synthetic chemerin-derived peptides suppress inflammation through ChemR23

    PubMed Central

    Cash, Jenna L.; Hart, Rosie; Russ, Andreas; Dixon, John P.C.; Colledge, William H.; Doran, Joanne; Hendrick, Alan G.; Carlton, Mark B.L.; Greaves, David R.

    2008-01-01

    Chemerin is a chemotactic protein that binds to the G protein–coupled receptor, ChemR23. We demonstrate that murine chemerin possesses potent antiinflammatory properties that are absolutely dependent on proteolytic processing. A series of peptides was designed, and only those identical to specific C-terminal chemerin sequences exerted antiinflammatory effects at picomolar concentrations in vitro. One of these, chemerin15 (C15; A140-A154), inhibited macrophage (MΦ) activation to a similar extent as proteolyzed chemerin, but exhibited reduced activity as a MΦ chemoattractant. Intraperitoneal administration of C15 (0.32 ng/kg) to mice before zymosan challenge conferred significant protection against zymosan-induced peritonitis, suppressing neutrophil (63%) and monocyte (62%) recruitment with a concomitant reduction in proinflammatory mediator expression. Importantly, C15 was unable to ameliorate zymosan-induced peritonitis in ChemR23−/− mice, demonstrating that C15's antiinflammatory effects are entirely ChemR23 dependent. In addition, administration of neutralizing anti-chemerin antibody before zymosan challenge resulted in a significant exacerbation of peritoneal inflammation (up to 170%), suggesting an important endogenous antiinflammatory role for chemerin-derived species. Collectively, these results show that chemerin-derived peptides may represent a novel therapeutic strategy for the treatment of inflammatory diseases through ChemR23. PMID:18391062

  12. A History of ChemMatters Magazine

    ERIC Educational Resources Information Center

    Tinnesand, Michael J.

    2007-01-01

    ChemMatters, the chemistry magazine published since 1983, has always provided interesting topics for chemistry students. The American Chemical Society publishes the magazine and many well-known authors like Isaac Asimov, Glen Seaborg and Derek Davenport have contributed to the magazine and the magazine has succeeded in its goal of demystifying…

  13. ChemDoodle Web Components: HTML5 toolkit for chemical graphics, interfaces, and informatics.

    PubMed

    Burger, Melanie C

    2015-01-01

    ChemDoodle Web Components (abbreviated CWC, iChemLabs, LLC) is a light-weight (~340 KB) JavaScript/HTML5 toolkit for chemical graphics, structure editing, interfaces, and informatics based on the proprietary ChemDoodle desktop software. The library uses and WebGL technologies and other HTML5 features to provide solutions for creating chemistry-related applications for the web on desktop and mobile platforms. CWC can serve a broad range of scientific disciplines including crystallography, materials science, organic and inorganic chemistry, biochemistry and chemical biology. CWC is freely available for in-house use and is open source (GPL v3) for all other uses.Graphical abstractAdd interactive 2D and 3D chemical sketchers, graphics, and spectra to websites and apps with ChemDoodle Web Components.

  14. FastChem: An ultra-fast equilibrium chemistry

    NASA Astrophysics Data System (ADS)

    Kitzmann, Daniel; Stock, Joachim

    2018-04-01

    FastChem is an equilibrium chemistry code that calculates the chemical composition of the gas phase for given temperatures and pressures. Written in C++, it is based on a semi-analytic approach, and is optimized for extremely fast and accurate calculations.

  15. The PubChem chemical structure sketcher

    PubMed Central

    2009-01-01

    PubChem is an important public, Web-based information source for chemical and bioactivity information. In order to provide convenient structure search methods on compounds stored in this database, one mandatory component is a Web-based drawing tool for interactive sketching of chemical query structures. Web-enabled chemical structure sketchers are not new, being in existence for years; however, solutions available rely on complex technology like Java applets or platform-dependent plug-ins. Due to general policy and support incident rate considerations, Java-based or platform-specific sketchers cannot be deployed as a part of public NCBI Web services. Our solution: a chemical structure sketching tool based exclusively on CGI server processing, client-side JavaScript functions, and image sequence streaming. The PubChem structure editor does not require the presence of any specific runtime support libraries or browser configurations on the client. It is completely platform-independent and verified to work on all major Web browsers, including older ones without support for Web2.0 JavaScript objects. PMID:20298522

  16. Air Quality Modeling and Forecasting over the United States Using WRF-Chem

    NASA Astrophysics Data System (ADS)

    Boxe, C.; Hafsa, U.; Blue, S.; Emmanuel, S.; Griffith, E.; Moore, J.; Tam, J.; Khan, I.; Cai, Z.; Bocolod, B.; Zhao, J.; Ahsan, S.; Gurung, D.; Tang, N.; Bartholomew, J.; Rafi, R.; Caltenco, K.; Rivas, M.; Ditta, H.; Alawlaqi, H.; Rowley, N.; Khatim, F.; Ketema, N.; Strothers, J.; Diallo, I.; Owens, C.; Radosavljevic, J.; Austin, S. A.; Johnson, L. P.; Zavala-Gutierrez, R.; Breary, N.; Saint-Hilaire, D.; Skeete, D.; Stock, J.; Salako, O.

    2016-12-01

    WRF-Chem is the Weather Research and Forecasting (WRF) model coupled with Chemistry. The model simulates the emission, transport, mixing, and chemical transformation of trace gases and aerosols simultaneously with the meteorology. The model is used for investigation of regional-scale air quality, field program analysis, and cloud-scale interactions between clouds and chemistry. The development of WRF-Chem is a collaborative effort among the community led by NOAA/ESRL scientists. The Official WRF-Chem web page is located at the NOAA web site. Our model development is closely linked with both NOAA/ESRL and DOE/PNNL efforts. Description of PNNL WRF-Chem model development is located at the PNNL web site as well as the PNNL Aerosol Modeling Testbed. High school and undergraduate students, representative of academic institutions throughout USA's Tri-State Area (New York, New Jersey, Connecticut), set up WRF-Chem on CUNY CSI's High Performance Computing Center. Students learned the back-end coding that governs WRF-Chems structure and the front-end coding that displays visually specified weather simulations and forecasts. Students also investigated the impact, to select baseline simulations/forecasts, due to the reaction, NO2 + OH + M → HOONO + M (k = 9.2 × 10-12 cm3 molecule-1 s-1, Mollner et al. 2010). The reaction of OH and NO2 to form gaseous nitric acid (HONO2) is among the most influential and in atmospheric chemistry. Till a few years prior, its rate coefficient remained poorly determined under tropospheric conditions because of difficulties in making laboratory measurements at 760 torr. These activities fosters student coding competencies and deep insights into weather forecast and air quality.

  17. ChemCam rock laser for Mars Science Laboratory "Curiosity"

    ScienceCinema

    Wiens, Roger

    2018-02-06

    Los Alamos has a long history of space-related instruments, tied primarily to its role in defense-related treaty verification. Space-based detectors have helped determine the differences between signals from lightning bolts and potential nuclear explosions. LANL-developed gamma-ray detection instruments first revealed the existence of what we now know as gamma-ray bursts, an exciting area of astrophysical research. And the use of LANL instruments on varied space missions continues with such products as the ChemCam rock laser for NASA, shown here. The Engineering Model of the ChemCam Mars Science Laboratory rover instrument arrived at NASA's Jet Propulsion Laboratory on February 6, 2008. The Flight Model was shipped in August, 2010 for installation on the rover at JPL. ChemCam will use imaging and laser-induced breakdown spectroscopy (LIBS) to determine rock and soil compositions on Mars, up to 9 meters from the rover. The engineering model is being integrated into the rover test bed for the development and testing of the rover software. The actual flight model components were concurrently assembled at Los Alamos and in Toulouse, France. The Mars Science Laboratory is scheduled to launch in 2011. Animations courtesy of JPL/NASA.

  18. Torsional Angle Driver (TorAD) System for HyperChem/Excel

    NASA Astrophysics Data System (ADS)

    Starkey, Ronald

    1999-02-01

    The torsional angle driver system for HyperChem/Excel is a package of several Excel spreadsheets and macro programs to be used with HyperChem to obtain and plot information, such as total energy, for the conformations that result from a 360° rotation about a torsional angle system in a molecule. The TorAD system also includes several HyperChem scripts to facilitate its use. TorAD was developed for use in the undergraduate organic chemistry laboratory. The results obtained with TorAD could be obtained manually with HyperChem, but it would take considerable time and would not be instructive to the students. Use of the TorAD system allows students to spend their time on the more important aspect of conformation analysisinterpretation of results. The Excel spreadsheet/macro programs in TorAD include:

    · Tor_xl_a and tor_xl obtain and plot the total energy at 5° torsional-angle intervals. The calculation method, the torsional-angle restraint, and the structure to be used at each angle can be set by the user. The advanced version, tor_xl_a, which requires HyperChem 4.5 or later, also allows torsional-angle structures to be saved for later recall as individual structures or, using a HyperChem script, in a movie format. It also provides a rapid scan of the 360° rotation where only single-point calculations, rather than geometry optimizations, are performed. The tor_xl system will perform routine tasks in a manner suitable for most instructional settings. · Tor_Comp performs molecular mechanics optimizations at 5° intervals and obtains and plots four energy parameters (total, torsional, nonbonded, and bond [bend plus stretch] energy) as a function of torsional angle. The calculation method and the restraint can be specified. · TorDipol produces a plot of the total energy and the calculated dipole moment at 5° steps of the torsional angle. The default calculation is the semi-empirical AM

  19. Calibrating the ChemCam LIBS for Carbonate Minerals on Mars

    DOE R&D Accomplishments Database

    Wiens, Roger C.; Clegg, Samuel M.; Ollila, Ann M.; Barefield, James E.; Lanza, Nina; Newsom, Horton E.

    2009-01-01

    The ChemCam instrument suite on board the NASA Mars Science Laboratory (MSL) rover includes the first LIBS instrument for extraterrestrial applications. Here we examine carbonate minerals in a simulated martian environment using the LIDS technique in order to better understand the in situ signature of these materials on Mars. Both chemical composition and rock type are determined using multivariate analysis (MVA) techniques. Composition is confirmed using scanning electron microscopy (SEM) techniques. Our initial results suggest that ChemCam can recognize and differentiate between carbonate materials on Mars.

  20. Drilled Hole and ChemCam Marks at Cumberland

    NASA Image and Video Library

    2013-06-05

    The Chemistry and Camera ChemCam instrument on NASA Mars rover Curiosity was used to check the composition of gray tailings from the hole in rock target Cumberland that the rover drilled on May 19, 2013.

  1. Curiosity ChemCam Analyzes Rocks, Soils and Dust

    NASA Image and Video Library

    2013-04-08

    This diagram shows how materials analyzed by the ChemCam instrument on NASA Curiosity Mars rover during the first 100 Martian days of the mission differed with regard to hydrogen content horizontal axis and alkali vertical axis.

  2. PubChem3D: Conformer generation

    PubMed Central

    2011-01-01

    Background PubChem, an open archive for the biological activities of small molecules, provides search and analysis tools to assist users in locating desired information. Many of these tools focus on the notion of chemical structure similarity at some level. PubChem3D enables similarity of chemical structure 3-D conformers to augment the existing similarity of 2-D chemical structure graphs. It is also desirable to relate theoretical 3-D descriptions of chemical structures to experimental biological activity. As such, it is important to be assured that the theoretical conformer models can reproduce experimentally determined bioactive conformations. In the present study, we investigate the effects of three primary conformer generation parameters (the fragment sampling rate, the energy window size, and force field variant) upon the accuracy of theoretical conformer models, and determined optimal settings for PubChem3D conformer model generation and conformer sampling. Results Using the software package OMEGA from OpenEye Scientific Software, Inc., theoretical 3-D conformer models were generated for 25,972 small-molecule ligands, whose 3-D structures were experimentally determined. Different values for primary conformer generation parameters were systematically tested to find optimal settings. Employing a greater fragment sampling rate than the default did not improve the accuracy of the theoretical conformer model ensembles. An ever increasing energy window did increase the overall average accuracy, with rapid convergence observed at 10 kcal/mol and 15 kcal/mol for model building and torsion search, respectively; however, subsequent study showed that an energy threshold of 25 kcal/mol for torsion search resulted in slightly improved results for larger and more flexible structures. Exclusion of coulomb terms from the 94s variant of the Merck molecular force field (MMFF94s) in the torsion search stage gave more accurate conformer models at lower energy windows. Overall

  3. PubChem atom environments.

    PubMed

    Hähnke, Volker D; Bolton, Evan E; Bryant, Stephen H

    2015-01-01

    Atom environments and fragments find wide-spread use in chemical information and cheminformatics. They are the basis of prediction models, an integral part in similarity searching, and employed in structure search techniques. Most of these methods were developed and evaluated on the relatively small sets of chemical structures available at the time. An analysis of fragment distributions representative of most known chemical structures was published in the 1970s using the Chemical Abstracts Service data system. More recently, advances in automated synthesis of chemicals allow millions of chemicals to be synthesized by a single organization. In addition, open chemical databases are readily available containing tens of millions of chemical structures from a multitude of data sources, including chemical vendors, patents, and the scientific literature, making it possible for scientists to readily access most known chemical structures. With this availability of information, one can now address interesting questions, such as: what chemical fragments are known today? How do these fragments compare to earlier studies? How unique are chemical fragments found in chemical structures? For our analysis, after hydrogen suppression, atoms were characterized by atomic number, formal charge, implicit hydrogen count, explicit degree (number of neighbors), valence (bond order sum), and aromaticity. Bonds were differentiated as single, double, triple or aromatic bonds. Atom environments were created in a circular manner focused on a central atom with radii from 0 (atom types) up to 3 (representative of ECFP_6 fragments). In total, combining atom types and atom environments that include up to three spheres of nearest neighbors, our investigation identified 28,462,319 unique fragments in the 46 million structures found in the PubChem Compound database as of January 2013. We could identify several factors inflating the number of environments involving transition metals, with many

  4. ChemCam rock laser for Mars Science Laboratory "Curiosity"

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wiens, Roger

    2010-09-03

    Los Alamos has a long history of space-related instruments, tied primarily to its role in defense-related treaty verification. Space-based detectors have helped determine the differences between signals from lightning bolts and potential nuclear explosions. LANL-developed gamma-ray detection instruments first revealed the existence of what we now know as gamma-ray bursts, an exciting area of astrophysical research. And the use of LANL instruments on varied space missions continues with such products as the ChemCam rock laser for NASA, shown here. The Engineering Model of the ChemCam Mars Science Laboratory rover instrument arrived at NASA's Jet Propulsion Laboratory on February 6, 2008.more » The Flight Model was shipped in August, 2010 for installation on the rover at JPL. ChemCam will use imaging and laser-induced breakdown spectroscopy (LIBS) to determine rock and soil compositions on Mars, up to 9 meters from the rover. The engineering model is being integrated into the rover test bed for the development and testing of the rover software. The actual flight model components were concurrently assembled at Los Alamos and in Toulouse, France. The Mars Science Laboratory is scheduled to launch in 2011. Animations courtesy of JPL/NASA.« less

  5. ChemCam Rock Laser for the Mars Science Laboratory

    ScienceCinema

    LANL

    2017-12-09

    Los Alamos has a long history of space-related instr... Los Alamos has a long history of space-related instruments, tied primarily to its role in defense-related treaty verification. Space-based detectors have helped determine the differences between signals from lightning bolts and potential nuclear explosions. LANL-developed gamma-ray detection instruments first revealed the existence of what we now know as gamma-ray bursts, an exciting area of astrophysical research. And the use of LANL instruments on varied space missions continues with such products as the ChemCam rock laser for NASA, shown here. The Engineering Model of the ChemCam Mars Science Laboratory rover instrument arrived at NASA's Jet Propulsion Laboratory on February 6, 2008. ChemCam will use imaging and laser-induced breakdown spectroscopy (LIBS) to determine rock and soil compositions on Mars, up to 9 meters from the rover. The engineering model is being integrated into the rover test bed for the development and testing of the rover software. The actual flight model components are concurrently being assembled at Los Alamos and in Toulouse, France, and will be delivered to JPL in July. The Mars Science Laboratory is scheduled to launch in 2009. Animations courtesy of JPL/NASA.

  6. Characterising Brazilian biomass burning emissions using WRF-Chem with MOSAIC sectional aerosol

    NASA Astrophysics Data System (ADS)

    Archer-Nicholls, S.; Lowe, D.; Darbyshire, E.; Morgan, W. T.; Bela, M. M.; Pereira, G.; Trembath, J.; Kaiser, J. W.; Longo, K. M.; Freitas, S. R.; Coe, H.; McFiggans, G.

    2015-03-01

    The South American Biomass Burning Analysis (SAMBBA) field campaign took detailed in situ flight measurements of aerosol during the 2012 dry season to characterise biomass burning aerosol and improve understanding of its impacts on weather and climate. Developments have been made to the Weather Research and Forecast model with chemistry (WRF-Chem) model to improve the representation of biomass burning aerosol in the region, by coupling a sectional aerosol scheme to the plume-rise parameterisation. Brazilian Biomass Burning Emissions Model (3BEM) fire emissions are used, prepared using PREP-CHEM-SRC, and mapped to CBM-Z and MOSAIC species. Model results have been evaluated against remote sensing products, AERONET sites, and four case studies of flight measurements from the SAMBBA campaign. WRF-Chem predicted layers of elevated aerosol loadings (5-20 μg sm-3) of particulate organic matter at high altitude (6-8 km) over tropical forest regions, while flight measurements showed a sharp decrease above 2-4 km altitude. This difference was attributed to the plume-rise parameterisation overestimating injection height. The 3BEM emissions product was modified using estimates of active fire size and burned area for the 2012 fire season, which reduced the fire size. The enhancement factor for fire emissions was increased from 1.3 to 5 to retain reasonable aerosol optical depths (AODs). The smaller fire size lowered the injection height of the emissions, but WRF-Chem still showed elevated aerosol loadings between 4-5 km altitude. Over eastern cerrado (savannah-like) regions, both modelled and measured aerosol loadings decreased above approximately 4 km altitude. Compared with MODIS satellite data and AERONET sites, WRF-Chem represented AOD magnitude well (between 0.3-1.5) over western tropical forest fire regions in the first half of the campaign, but tended to over-predict them in the second half, when precipitation was more significant. Over eastern cerrado regions, WRF-Chem

  7. Characterising Brazilian biomass burning emissions using WRF-Chem with MOSAIC sectional aerosol

    NASA Astrophysics Data System (ADS)

    Archer-Nicholls, S.; Lowe, D.; Darbyshire, E.; Morgan, W. T.; Bela, M. M.; Pereira, G.; Trembath, J.; Kaiser, J. W.; Longo, K. M.; Freitas, S. R.; Coe, H.; McFiggans, G.

    2014-09-01

    The South American Biomass Burning Analysis (SAMBBA) field campaign took detailed in-situ flight measurements of aerosol during the 2012 dry season to characterise biomass burning aerosol and improve understanding of its impacts on weather and climate. Developments have been made to the Weather research and Forecast model with chemistry (WRF-Chem) model to improve the representation of biomass burning aerosol in the region by coupling a sectional aerosol scheme to the plume rise parameterisation. Brazilian Biomass Burning Emissions Model (3BEM) fire emissions are used, prepared using PREP-CHEM-SRC, and mapped to CBM-Z and MOSAIC species. Model results have been evaluated against remote sensing products, AERONET sites, and four case studies of flight measurements from the SAMBBA campaign. WRF-Chem predicted layers of elevated aerosol loadings (5-20 μg sm-3) of particulate organic matter at high altitude (6-8 km) over tropical forest regions, while flight measurements showed a sharp decrease above 2-4 km altitude. This difference was attributed to the plume-rise parameterisation overestimating injection height. The 3BEM emissions product was modified using estimates of active fire size and burned area for the 2012 fire season, which reduced the fire size. The enhancement factor for fire emissions was increased from 1.3 to 5 to retain reasonable aerosol optical depths (AOD). The smaller fire size lowered the injection height of the emissions, but WRF-Chem still showed elevated aerosol loadings between 4-5 km altitude. Over eastern Cerrado (savannah-like) regions, both modelled and measured aerosol loadings decreased above approximately 4 km altitude. Compared with MODIS satellite data and AERONET sites, WRF-Chem represented AOD magnitude well (between 0.3-1.5) over western tropical forest fire regions in the first half of the campaign, but tended to over-predict them in the second half, when precipitation was more significant. Over eastern Cerrado regions, WRF-Chem

  8. Tropospheric ozone using an emission tagging technique in the CAM-Chem and WRF-Chem models

    NASA Astrophysics Data System (ADS)

    Lupascu, A.; Coates, J.; Zhu, S.; Butler, T. M.

    2017-12-01

    Tropospheric ozone is a short-lived climate forcing pollutant. High concentration of ozone can affect human health (cardiorespiratory and increased mortality due to long-term exposure), and also it damages crops. Attributing ozone concentrations to the contributions from different sources would indicate the effects of locally emitted or transported precursors on ozone levels in specific regions. This information could be used as an important component of the design of emissions reduction strategies by indicating which emission sources could be targeted for effective reductions, thus reducing the burden of ozone pollution. Using a "tagging" approach within the CAM-Chem (global) and WRF-Chem (regional) models, we can quantify the contribution of individual emission of NOx and VOC precursors on air quality. Hence, when precursor emissions of NOx are tagged, we have seen that the largest contributors on ozone levels are the anthropogenic sources, while in the case of precursor emissions of VOCs, the biogenic sources and methane account for more than 50% of ozone levels. Further, we have extended the NOx tagging method in order to investigate continental source region contributions to concentrations of ozone over various receptor regions over the globe, with a zoom over Europe. In general, summertime maximum ozone in most receptor regions is largely attributable to local emissions of anthropogenic NOx and biogenic VOC. During the rest of the year, especially during springtime, ozone in most receptor regions shows stronger influences from anthropogenic emissions of NOx and VOC in remote source regions.

  9. Spark Generated by ChemCam Laser During Tests

    NASA Image and Video Library

    2010-09-21

    The ChemCam instrument for NASA Mars Science Laboratory mission uses a pulsed laser beam to vaporize a pinhead-size target, producing a flash of light from the ionized material plasma that can be analyzed to identify chemical elements in the target.

  10. ScrubChem: Cleaning of PubChem Bioassay Data to Create Diverse and Massive Bioactivity Datasets for Use in Modeling Applications (SOT)

    EPA Science Inventory

    The PubChem Bioassay database is a non-curated public repository with bioactivity data from 64 sources, including: ChEMBL, BindingDb, DrugBank, Tox21, NIH Molecular Libraries Screening Program, and various academic, government, and industrial contributors. However, this data is d...

  11. Calcium Sulfate Characterized by ChemCam/Curiosity at Gale Crater, Mars

    NASA Technical Reports Server (NTRS)

    Nachon, M.; Clegg, S. N.; Mangold, N.; Schroeder, S.; Kah, L. C.; Dromart, G.; Ollila, A.; Johnson, J. R.; Oehler, D. Z.; Bridges, J. C.; hide

    2014-01-01

    Onboard the Mars Science Laboratory (MSL) Curiosity rover, the ChemCam instrument consists of :(1) a Laser-Induced Breakdown Spectrometer (LIBS) for elemental analysis of the targets [1;2] and (2) a Remote Micro Imager (RMI), for the imaging context of laser analysis [3]. Within the Gale crater, Curiosity traveled from Bradbury Landing through the Rocknest region and into Yellowknife Bay (YB). In the latter, abundant light-toned fracture-fill material were seen [4;5]. ChemCam analysis demonstrate that those fracture fills consist of calcium sulfates [6].

  12. ChemCam Mast Unit Being Prepared for Laser Firing

    NASA Image and Video Library

    2010-12-23

    Researchers prepare for a test of the Chemistry and Camera ChemCam instrument that will fly on NASA Mars Science Laboratory mission; researchers are preparing the instrument mast unit for a laser firing test.

  13. ChemCalc: a building block for tomorrow's chemical infrastructure.

    PubMed

    Patiny, Luc; Borel, Alain

    2013-05-24

    Web services, as an aspect of cloud computing, are becoming an important part of the general IT infrastructure, and scientific computing is no exception to this trend. We propose a simple approach to develop chemical Web services, through which servers could expose the essential data manipulation functionality that students and researchers need for chemical calculations. These services return their results as JSON (JavaScript Object Notation) objects, which facilitates their use for Web applications. The ChemCalc project http://www.chemcalc.org demonstrates this approach: we present three Web services related with mass spectrometry, namely isotopic distribution simulation, peptide fragmentation simulation, and molecular formula determination. We also developed a complete Web application based on these three Web services, taking advantage of modern HTML5 and JavaScript libraries (ChemDoodle and jQuery).

  14. HExpoChem: a systems biology resource to explore human exposure to chemicals.

    PubMed

    Taboureau, Olivier; Jacobsen, Ulrik Plesner; Kalhauge, Christian; Edsgärd, Daniel; Rigina, Olga; Gupta, Ramneek; Audouze, Karine

    2013-05-01

    Humans are exposed to diverse hazardous chemicals daily. Although an exposure to these chemicals is suspected to have adverse effects on human health, mechanistic insights into how they interact with the human body are still limited. Therefore, acquisition of curated data and development of computational biology approaches are needed to assess the health risks of chemical exposure. Here we present HExpoChem, a tool based on environmental chemicals and their bioactivities on human proteins with the objective of aiding the qualitative exploration of human exposure to chemicals. The chemical-protein interactions have been enriched with a quality-scored human protein-protein interaction network, a protein-protein association network and a chemical-chemical interaction network, thus allowing the study of environmental chemicals through formation of protein complexes and phenotypic outcomes enrichment. HExpoChem is available at http://www.cbs.dtu.dk/services/HExpoChem-1.0/.

  15. ChemScreener: A Distributed Computing Tool for Scaffold based Virtual Screening.

    PubMed

    Karthikeyan, Muthukumarasamy; Pandit, Deepak; Vyas, Renu

    2015-01-01

    In this work we present ChemScreener, a Java-based application to perform virtual library generation combined with virtual screening in a platform-independent distributed computing environment. ChemScreener comprises a scaffold identifier, a distinct scaffold extractor, an interactive virtual library generator as well as a virtual screening module for subsequently selecting putative bioactive molecules. The virtual libraries are annotated with chemophore-, pharmacophore- and toxicophore-based information for compound prioritization. The hits selected can then be further processed using QSAR, docking and other in silico approaches which can all be interfaced within the ChemScreener framework. As a sample application, in this work scaffold selectivity, diversity, connectivity and promiscuity towards six important therapeutic classes have been studied. In order to illustrate the computational power of the application, 55 scaffolds extracted from 161 anti-psychotic compounds were enumerated to produce a virtual library comprising 118 million compounds (17 GB) and annotated with chemophore, pharmacophore and toxicophore based features in a single step which would be non-trivial to perform with many standard software tools today on libraries of this size.

  16. Chemerin15 inhibits neutrophil-mediated vascular inflammation and myocardial ischemia-reperfusion injury through ChemR23

    PubMed Central

    Cash, Jenna L; Bena, Stefania; Headland, Sarah E; McArthur, Simon; Brancaleone, Vincenzo; Perretti, Mauro

    2013-01-01

    Neutrophil activation and adhesion must be tightly controlled to prevent complications associated with excessive inflammatory responses. The role of the anti-inflammatory peptide chemerin15 (C15) and the receptor ChemR23 in neutrophil physiology is unknown. Here, we report that ChemR23 is expressed in neutrophil granules and rapidly upregulated upon neutrophil activation. C15 inhibits integrin activation and clustering, reducing neutrophil adhesion and chemotaxis in vitro. In the inflamed microvasculature, C15 rapidly modulates neutrophil physiology inducing adherent cell detachment from the inflamed endothelium, while reducing neutrophil recruitment and heart damage in a murine myocardial infarction model. These effects are mediated through ChemR23. We identify the C15/ChemR23 pathway as a new regulator and thus therapeutic target in neutrophil-driven pathologies. PMID:23999103

  17. Handheld Chem/Biosensor Using Extreme Conformational Changes in Designed Binding Proteins to Enhance Surface Plasmon Resonance (SPR)

    DTIC Science & Technology

    2016-04-01

    AFCEC-CX-TY-TR-2016-0007 HANDHELD CHEM/ BIOSENSOR USING EXTREME CONFORMATIONAL CHANGES IN DESIGNED BINDING PROTEINS TO ENHANCE SURFACE PLASMON...Include area code) 03/24/2016 Abstract 08/14/2015--03/31/2016 Handheld chem/ biosensor using extreme conformational changes in designed binding...Baltimore, Maryland on 17-21 April 2016. We propose the development of a highly sensitive handheld chem/ biosensor device using a novel class of engineered

  18. Evaluation of Lateral-Flow Clostridium botulinum Neurotoxin Detection Kits for Food Analysis

    DTIC Science & Technology

    2005-02-08

    toxic proteins. Annu. Rev. Microbiol. 53:551–575. 19. Ketema, F., C. Zeh, D. C. Edelman, R. Saville, and N. T. Constantine. 2001. Assessment of the...H. H., and F. Sun. 2001. Assessing cyanogen content in cassava -based food using the enzyme-dipstick method. Food Chem. Toxicol. 39:649–653. VOL. 71, 2005 RAPID DETECTION OF C. BOTULINUM NEUROTOXIN 3941

  19. Soil diversity and hydration as observed by ChemCam at Gale crater, Mars

    USGS Publications Warehouse

    Meslin, P.-Y.; Gasnault, O.; Forni, O.; Schroder, S.; Cousin, A.; Berger, G.; Clegg, S.M.; Lasue, J.; Maurice, S.; Sautter, V.; Le Mouélic, S.; Wiens, R.C.; Fabre, C.; Goetz, W.; Bish, D.L.; Mangold, N.; Ehlmann, B.; Lanza, N.; Harri, A.-M.; Anderson, Ryan Bradley; Rampe, E.; McConnochie, T.H.; Pinet, P.; Blaney, D.; ,; Archer, D.; Barraclough, B.; Bender, S.; Blake, D.; Blank, J.G.; Bridges, N.; Clark, B. C.; DeFlores, L.; Delapp, D.; Dromart, G.; Dyar, M.D.; Fisk, M. R.; Gondet, B.; Grotzinger, J.; Herkenhoff, K.; Johnson, J.; Lacour, J.-L.; Langevin, Y.; Leshin, L.; Lewin, E.; Madsen, M.B.; Melikechi, N.; Mezzacappa, Alissa; Mischna, M.A.; Moores, J.E.; Newsom, H.; Ollila, A.; ,; Renno, N.; Sirven, J.B.; Tokar, R.; de la Torre, M.; d'Uston, L.; Vaniman, D.; Yingst, A.

    2013-01-01

    The ChemCam instrument, which provides insight into martian soil chemistry at the submillimeter scale, identified two principal soil types along the Curiosity rover traverse: a fine-grained mafic type and a locally derived, coarse-grained felsic type. The mafic soil component is representative of widespread martian soils and is similar in composition to the martian dust. It possesses a ubiquitous hydrogen signature in ChemCam spectra, corresponding to the hydration of the amorphous phases found in the soil by the CheMin instrument. This hydration likely accounts for an important fraction of the global hydration of the surface seen by previous orbital measurements. ChemCam analyses did not reveal any significant exchange of water vapor between the regolith and the atmosphere. These observations provide constraints on the nature of the amorphous phases and their hydration.

  20. Soil diversity and hydration as observed by ChemCam at Gale crater, Mars.

    PubMed

    Meslin, P-Y; Gasnault, O; Forni, O; Schröder, S; Cousin, A; Berger, G; Clegg, S M; Lasue, J; Maurice, S; Sautter, V; Le Mouélic, S; Wiens, R C; Fabre, C; Goetz, W; Bish, D; Mangold, N; Ehlmann, B; Lanza, N; Harri, A-M; Anderson, R; Rampe, E; McConnochie, T H; Pinet, P; Blaney, D; Léveillé, R; Archer, D; Barraclough, B; Bender, S; Blake, D; Blank, J G; Bridges, N; Clark, B C; DeFlores, L; Delapp, D; Dromart, G; Dyar, M D; Fisk, M; Gondet, B; Grotzinger, J; Herkenhoff, K; Johnson, J; Lacour, J-L; Langevin, Y; Leshin, L; Lewin, E; Madsen, M B; Melikechi, N; Mezzacappa, A; Mischna, M A; Moores, J E; Newsom, H; Ollila, A; Perez, R; Renno, N; Sirven, J-B; Tokar, R; de la Torre, M; d'Uston, L; Vaniman, D; Yingst, A

    2013-09-27

    The ChemCam instrument, which provides insight into martian soil chemistry at the submillimeter scale, identified two principal soil types along the Curiosity rover traverse: a fine-grained mafic type and a locally derived, coarse-grained felsic type. The mafic soil component is representative of widespread martian soils and is similar in composition to the martian dust. It possesses a ubiquitous hydrogen signature in ChemCam spectra, corresponding to the hydration of the amorphous phases found in the soil by the CheMin instrument. This hydration likely accounts for an important fraction of the global hydration of the surface seen by previous orbital measurements. ChemCam analyses did not reveal any significant exchange of water vapor between the regolith and the atmosphere. These observations provide constraints on the nature of the amorphous phases and their hydration.

  1. Sulfur Geochemical Analysis and Interpretation with ChemCam on the Curiosity Rover

    NASA Astrophysics Data System (ADS)

    Clegg, S. M.; Anderson, R. B.; Frydenvang, J.; Forni, O.; Newsom, H. E.; Blaney, D. L.; Maurice, S.; Wiens, R. C.

    2017-12-01

    The Curiosity rover has encountered many forms of sulfur including calcium sulfate veins [1], hydrated Mg sulfates, and Fe sulfates along the traverse through Gale crater. A new SO3 calibration model for the remote Laser-Induced Breakdown Spectroscopy (LIBS) technique used by the ChemCam instrument enables improved quantitative analysis of SO3, which has not been previously reported by ChemCam on a routine or quantitative basis. In this paper, the details of this new LIBS calibration model will be described and applied to many disparate Mars targets. Among them, Mavor contains a calcium sulfate vein surrounded by bedrock. In contrast, Jake M. is a float rock, Wernecke is a bedrock, Cumberland and Windjana are drill targets. In 2015 the ChemCam instrument team completed a re-calibration of major elements based on a significantly expanded set of >500 geochemical standards using the ChemCam testbed at Los Alamos National Laboratory [2]. In addition to these standards, the SO3 compositional range was recently extended with a series of doped samples containing various mixtures of Ca- and Mg-sulfate with basalt BHVO2. Spectra from these standards were processed per [4]. Calibration and Mars spectra were converted to peak-area-summed LIBS spectra that enables the SO3 calibration. These peak-area spectra were used to generate three overlapping partial least squares (PLS1) calibration sub-models as described by Anderson et al. [3, 5]. ChemCam analysis of Mavor involved a 3x3 raster in which locations 5 and 6 primarily probed Ca-sulfate material. The new ChemCam SO3 compositions for Mavor 5 and Mavor 6 are 48.6±1.2 and 50.3±1.2 wt% SO3, respectively. The LIBS spectra also recorded the presence of other elements that are likely responsible for the departure from pure Ca-sulfate chemistry. On the low-abundance side, the remaining 7 Mavor locations, Jake M., Cumberland, Windjana, and Wernecke all contain much lower SO3, between 1.4±0.5 wt% and 2.3±0.3 wt% SO3. [1] Nachon et

  2. OrChem - An open source chemistry search engine for Oracle(R).

    PubMed

    Rijnbeek, Mark; Steinbeck, Christoph

    2009-10-22

    Registration, indexing and searching of chemical structures in relational databases is one of the core areas of cheminformatics. However, little detail has been published on the inner workings of search engines and their development has been mostly closed-source. We decided to develop an open source chemistry extension for Oracle, the de facto database platform in the commercial world. Here we present OrChem, an extension for the Oracle 11G database that adds registration and indexing of chemical structures to support fast substructure and similarity searching. The cheminformatics functionality is provided by the Chemistry Development Kit. OrChem provides similarity searching with response times in the order of seconds for databases with millions of compounds, depending on a given similarity cut-off. For substructure searching, it can make use of multiple processor cores on today's powerful database servers to provide fast response times in equally large data sets. OrChem is free software and can be redistributed and/or modified under the terms of the GNU Lesser General Public License as published by the Free Software Foundation. All software is available via http://orchem.sourceforge.net.

  3. OrChem - An open source chemistry search engine for Oracle®

    PubMed Central

    2009-01-01

    Background Registration, indexing and searching of chemical structures in relational databases is one of the core areas of cheminformatics. However, little detail has been published on the inner workings of search engines and their development has been mostly closed-source. We decided to develop an open source chemistry extension for Oracle, the de facto database platform in the commercial world. Results Here we present OrChem, an extension for the Oracle 11G database that adds registration and indexing of chemical structures to support fast substructure and similarity searching. The cheminformatics functionality is provided by the Chemistry Development Kit. OrChem provides similarity searching with response times in the order of seconds for databases with millions of compounds, depending on a given similarity cut-off. For substructure searching, it can make use of multiple processor cores on today's powerful database servers to provide fast response times in equally large data sets. Availability OrChem is free software and can be redistributed and/or modified under the terms of the GNU Lesser General Public License as published by the Free Software Foundation. All software is available via http://orchem.sourceforge.net. PMID:20298521

  4. Synergy of SAM and ChemCam instruments (Curiosity Rover) to Search for Organic Matter at Mars

    NASA Astrophysics Data System (ADS)

    Dequaire, T.; Coll, P.; Szopa, C.; Maurice, S.; Mangold, N.

    2014-07-01

    This work proposes to determine ChemCam capabilities to detect organic molecules in the martian rocks, by coupling LIBS and passive spectroscopy using the ChemCam testbed (IRAP) in order to select at best the samples analyzed by the SAM instrument.

  5. WRF/Chem-MADRID: Incorporation of an Improved Aerosol Module into WRF/Chem and Its Initial Application to the TexAQS2000 Episode

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zhang, Yang; Pan, Ying; Wang, K.

    2010-09-17

    The Model of Aerosol Dynamics, Reaction, Ionization and Dissolution (MADRID) with three improved gas/particle mass transfer approaches (i.e., bulk equilibrium (EQUI), hybrid (HYBR), and kinetic (KINE)) has been incorporated into the Weather Research and Forecast/Chemistry Model (WRF/Chem) (referred to as WRF/Chem-MADRID) and evaluated with a 5-day episode from the 2000 Texas Air Quality Study (TexAQS2000). WRF/Chem-MADRID demonstrates an overall good skill in simulating surface/aloft meteorological parameters and chemical concentrations, tropospheric O3 residuals, and aerosol optical depths. The discrepancies can be attributed to inaccuracies in meteorological predictions (e.g., overprediction in mid-day boundary layer height), inaccurate total emissions or their hourly variationsmore » (e.g., HCHO, olefins, other inorganic aerosols), and uncertainties in initial and boundary conditions for some species (e.g., other inorganic aerosols and O3) at surface and aloft. Major differences in the results among the three gas/particle mass transfer approaches occur over coastal areas, where EQUI predicts higher PM2.5 than HYBR and KINE due to improperly redistributing condensed nitrate from chloride depletion process to fine PM mode. The net direct, semi-direct, and indirect effects of PM2.5 decreased domain wide shortwave radiation by 11.2-14.4 W m-2 (or 4.1-5.6%), decreased near-surface temperature by 0.06-0.14 °C (or 0.2-0.4%), led to 125 to 796 cm-3 cloud condensation nuclei at a supersaturation of 0.1%, produced cloud droplet numbers as high as 2064 cm-3, and reduced domain wide mean precipitation by 0.22-0.59 mm day-1.« less

  6. ChemProt-2.0: visual navigation in a disease chemical biology database

    PubMed Central

    Kim Kjærulff, Sonny; Wich, Louis; Kringelum, Jens; Jacobsen, Ulrik P.; Kouskoumvekaki, Irene; Audouze, Karine; Lund, Ole; Brunak, Søren; Oprea, Tudor I.; Taboureau, Olivier

    2013-01-01

    ChemProt-2.0 (http://www.cbs.dtu.dk/services/ChemProt-2.0) is a public available compilation of multiple chemical–protein annotation resources integrated with diseases and clinical outcomes information. The database has been updated to >1.15 million compounds with 5.32 millions bioactivity measurements for 15 290 proteins. Each protein is linked to quality-scored human protein–protein interactions data based on more than half a million interactions, for studying diseases and biological outcomes (diseases, pathways and GO terms) through protein complexes. In ChemProt-2.0, therapeutic effects as well as adverse drug reactions have been integrated allowing for suggesting proteins associated to clinical outcomes. New chemical structure fingerprints were computed based on the similarity ensemble approach. Protein sequence similarity search was also integrated to evaluate the promiscuity of proteins, which can help in the prediction of off-target effects. Finally, the database was integrated into a visual interface that enables navigation of the pharmacological space for small molecules. Filtering options were included in order to facilitate and to guide dynamic search of specific queries. PMID:23185041

  7. Size, Shape, and Arrangement of Cellulose Microfibril in Higher Plant Cell Walls

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ding, S. Y.

    2013-01-01

    Plant cell walls from maize (Zea mays L.) are imaged using atomic force microscopy (AFM) at the sub-nanometer resolution. We found that the size and shape of fundamental cellulose elementary fibril (CEF) is essentially identical in different cell wall types, i.e., primary wall (PW), parenchyma secondary wall (pSW), and sclerenchyma secondary wall (sSW), which is consistent with previously proposed 36-chain model (Ding et al., 2006, J. Agric. Food Chem.). The arrangement of individual CEFs in these wall types exhibits two orientations. In PW, CEFs are horizontally associated through their hydrophilic faces, and the planar faces are exposed, forming ribbon-like macrofibrils.more » In pSW and sSW, CEFs are vertically oriented, forming layers, in which hemicelluloses are interacted with the hydrophobic faces of the CEF and serve as spacers between CEFs. Lignification occurs between CEF-hemicelluloses layers in secondary walls. Furthermore, we demonstrated quantitative analysis of plant cell wall accessibility to and digestibility by different cellulase systems at real-time using chemical imaging (e.g., stimulated Raman scattering) and fluorescence microscopy of labeled cellulases (Ding et al., 2012, Science, in press).« less

  8. Development and Performance of the Modularized, High-performance Computing and Hybrid-architecture Capable GEOS-Chem Chemical Transport Model

    NASA Astrophysics Data System (ADS)

    Long, M. S.; Yantosca, R.; Nielsen, J.; Linford, J. C.; Keller, C. A.; Payer Sulprizio, M.; Jacob, D. J.

    2014-12-01

    The GEOS-Chem global chemical transport model (CTM), used by a large atmospheric chemistry research community, has been reengineered to serve as a platform for a range of computational atmospheric chemistry science foci and applications. Development included modularization for coupling to general circulation and Earth system models (ESMs) and the adoption of co-processor capable atmospheric chemistry solvers. This was done using an Earth System Modeling Framework (ESMF) interface that operates independently of GEOS-Chem scientific code to permit seamless transition from the GEOS-Chem stand-alone serial CTM to deployment as a coupled ESM module. In this manner, the continual stream of updates contributed by the CTM user community is automatically available for broader applications, which remain state-of-science and directly referenceable to the latest version of the standard GEOS-Chem CTM. These developments are now available as part of the standard version of the GEOS-Chem CTM. The system has been implemented as an atmospheric chemistry module within the NASA GEOS-5 ESM. The coupled GEOS-5/GEOS-Chem system was tested for weak and strong scalability and performance with a tropospheric oxidant-aerosol simulation. Results confirm that the GEOS-Chem chemical operator scales efficiently for any number of processes. Although inclusion of atmospheric chemistry in ESMs is computationally expensive, the excellent scalability of the chemical operator means that the relative cost goes down with increasing number of processes, making fine-scale resolution simulations possible.

  9. New developments on ChemCam laser transmitter and potential applications for other planetology programs

    NASA Astrophysics Data System (ADS)

    Faure, Benoît; Durand, Eric; Maurice, Sylvestre; Bruneau, Didier; Montmessin, Franck

    2017-11-01

    ChemCam is a LIBS Instrument mounted on the MSL 2011 NASA mission. The laser transmitter of this Instrument has been developed by the French society Thales Optronique (former Thales Laser) with a strong technical support from CNES. The paper will first rapidly present the performance of this laser and will then describe the postChemCam developments realized on and around this laser for new planetology programs.

  10. Outreach within the Bristol ChemLabS CETL (Centre for Excellence in Teaching and Learning)

    ERIC Educational Resources Information Center

    Shallcross, Dudley E.; Harrison, Tim G.; Obey, Tim M.; Croker, Steve J.; Norman, Nick C.

    2013-01-01

    This paper presents an overview of the Bristol ChemLabS project. In particular, it describes the development and impacts of the outreach project within Bristol ChemLabS, the UK's Centre for Excellence in Teaching and Learning (CETL) in practical chemistry, and its continuation beyond the funded project. The major elements of working with both…

  11. A CNES remote operations center for the MSL ChemCam instrument

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wiens, Roger C; Lafaille, Vivian; Lorgny, Eric

    2010-01-01

    For the first time, a CNES remote operations center in Toulouse will be involved in the tactical operations of a Martian rover in order to operate the ChemCam science instrument in the framework of the NASA MSL (Mars Science Laboratory) mission in 2012. CNES/CESR and LANL have developed and delivered to JPL the ChemCam (Chemistry Camera) instrument located on the top of mast and in the body of the rover. This instrument incorporates a Laser-Induced Breakdown Spectrometer (LIBS) and a Remote Micro-Imager (RMI) for determining elemental compositions of rock targets or soil samples at remote distances from the rover (2-7more » m). An agreement has been achieved for operating ChemCam, alternatively, from Toulouse (FR) and Los Alamos (NM, USA), through the JPL ground data system in Pasadena (CA, USA) for a complete Martian year (2 years on Earth). After a brief overview of the MSL mission, this paper presents the instrument, the mission operational system and JPL organization requirements for the scientific investigators (PI and Co-Is). This paper emphasizes innovations applied on the ground segment components and on the operational approach to satisfy the requirements and constraints due to these shared and distributed operations over the world.« less

  12. ChemSource SourceBook, Version 2.0: Volume 1.

    ERIC Educational Resources Information Center

    Orna, Mary Virginia, Ed.; And Others

    ChemSource is designed as a strategy to help preservice and inservice high school chemistry teachers promote student learning more effectively. Its major premise is that well-designed laboratory investigations are an important avenue for cultivating student interest, engagement, and meaningful learning in chemistry. The SourceBook component of…

  13. ChemSource SourceBook, Version 2.0: Volume 2.

    ERIC Educational Resources Information Center

    Orna, Mary Virginia, Ed.; And Others

    ChemSource is designed as a strategy to help preservice and inservice high school chemistry teachers promote student learning more effectively. Its major premise is that well-designed laboratory investigations are an important avenue for cultivating student interest, engagement, and meaningful learning in chemistry. The SourceBook component of…

  14. ChemSource SourceBook, Version 2.0: Volume 3.

    ERIC Educational Resources Information Center

    Orna, Mary Virginia, Ed.; And Others

    ChemSource is designed as a strategy to help preservice and inservice high school chemistry teachers promote student learning more effectively. Its major premise is that well-designed laboratory investigations are an important avenue for cultivating student interest, engagement, and meaningful learning in chemistry. The SourceBook component of…

  15. iNuc-PhysChem: A Sequence-Based Predictor for Identifying Nucleosomes via Physicochemical Properties

    PubMed Central

    Feng, Peng-Mian; Ding, Chen; Zuo, Yong-Chun; Chou, Kuo-Chen

    2012-01-01

    Nucleosome positioning has important roles in key cellular processes. Although intensive efforts have been made in this area, the rules defining nucleosome positioning is still elusive and debated. In this study, we carried out a systematic comparison among the profiles of twelve DNA physicochemical features between the nucleosomal and linker sequences in the Saccharomyces cerevisiae genome. We found that nucleosomal sequences have some position-specific physicochemical features, which can be used for in-depth studying nucleosomes. Meanwhile, a new predictor, called iNuc-PhysChem, was developed for identification of nucleosomal sequences by incorporating these physicochemical properties into a 1788-D (dimensional) feature vector, which was further reduced to a 884-D vector via the IFS (incremental feature selection) procedure to optimize the feature set. It was observed by a cross-validation test on a benchmark dataset that the overall success rate achieved by iNuc-PhysChem was over 96% in identifying nucleosomal or linker sequences. As a web-server, iNuc-PhysChem is freely accessible to the public at http://lin.uestc.edu.cn/server/iNuc-PhysChem. For the convenience of the vast majority of experimental scientists, a step-by-step guide is provided on how to use the web-server to get the desired results without the need to follow the complicated mathematics that were presented just for the integrity in developing the predictor. Meanwhile, for those who prefer to run predictions in their own computers, the predictor's code can be easily downloaded from the web-server. It is anticipated that iNuc-PhysChem may become a useful high throughput tool for both basic research and drug design. PMID:23144709

  16. Benchmarking Ligand-Based Virtual High-Throughput Screening with the PubChem Database

    PubMed Central

    Butkiewicz, Mariusz; Lowe, Edward W.; Mueller, Ralf; Mendenhall, Jeffrey L.; Teixeira, Pedro L.; Weaver, C. David; Meiler, Jens

    2013-01-01

    With the rapidly increasing availability of High-Throughput Screening (HTS) data in the public domain, such as the PubChem database, methods for ligand-based computer-aided drug discovery (LB-CADD) have the potential to accelerate and reduce the cost of probe development and drug discovery efforts in academia. We assemble nine data sets from realistic HTS campaigns representing major families of drug target proteins for benchmarking LB-CADD methods. Each data set is public domain through PubChem and carefully collated through confirmation screens validating active compounds. These data sets provide the foundation for benchmarking a new cheminformatics framework BCL::ChemInfo, which is freely available for non-commercial use. Quantitative structure activity relationship (QSAR) models are built using Artificial Neural Networks (ANNs), Support Vector Machines (SVMs), Decision Trees (DTs), and Kohonen networks (KNs). Problem-specific descriptor optimization protocols are assessed including Sequential Feature Forward Selection (SFFS) and various information content measures. Measures of predictive power and confidence are evaluated through cross-validation, and a consensus prediction scheme is tested that combines orthogonal machine learning algorithms into a single predictor. Enrichments ranging from 15 to 101 for a TPR cutoff of 25% are observed. PMID:23299552

  17. Effects on Student Achievement in General Chemistry Following Participation in an Online Preparatory Course. ChemPrep, a Voluntary, Self-Paced, Online Introduction to Chemistry

    NASA Astrophysics Data System (ADS)

    Botch, Beatrice; Day, Roberta; Vining, William; Stewart, Barbara; Rath, Kenneth; Peterfreund, Alan; Hart, David

    2007-03-01

    ChemPrep was developed to be a stand-alone preparatory short-course to help students succeed in general chemistry. It is Web-based and delivered using the OWL system. Students reported that the ChemPrep materials (short information pages, parameterized questions with detailed feedback, tutorials, and answers to questions through the OWL message system) permitted them to work independently without the need for textbook or lecture. On average, students who completed ChemPrep had higher grades in the subsequent GenChem, Nursing, and Honors chemistry courses, with a greater percentage achieving a grade of C- or higher. Participation in ChemPrep was voluntary, and more women than men responded. Students in the Honors course enrolled in ChemPrep in higher percentages than students in GenChem and Nursing. SAT and departmental math placement exam scores were used as proxy measures of prior achievement and ability. Based on these, Honors chemistry ChemPrep users were on par with their peers but performed better in the course than non-users. In GenChem and Nursing chemistry courses, ChemPrep helped students of high prior achievement and ability perform better than their achievement scores would predict. Weaker or less motivated students did not respond to the voluntary offerings of ChemPrep in the same numbers as stronger or more motivated students, and we are seeking alternate ways to reach this population.

  18. Using Combustion Tracers to Estimate Surface Black Carbon Distributions in WRF-Chem

    NASA Astrophysics Data System (ADS)

    Raman, A.; Arellano, A. F.

    2015-12-01

    Black Carbon (BC) emissions significantly affect the global and regional climate, air quality, and human health. However, BC observations are currently limited in space and time; leading to considerable uncertainties in the estimates of BC distribution from regional and global models. Here, we investigate the usefulness of carbon monoxide (CO) in quantifying BC across continental United States (CONUS). We use high resolution EPA AQS observations of CO and IMPROVE BC to estimate BC/CO ratios. We model the BC and CO distribution using the community Weather Research and Forecasting model with Chemistry (WRF-Chem). We configured WRF-Chem using MOZART chemistry, NEI 2005, MEGAN, and FINNv1.5 for anthropogenic, biogenic and fire emissions, respectively. In this work, we address the following three key questions: 1) What are the discrepancies in the estimates of BC and CO distributions across CONUS during summer and winter periods?, 2) How do BC/CO ratios change for different spatial and temporal regimes?, 3) Can we get better estimates of BC from WRF-Chem if we use BC/CO ratios along with optimizing CO concentrations? We compare ratios derived from the model and observations and develop characteristic ratios for several geographical and temporal regimes. We use an independent set of measurements of BC and CO to evaluate these ratios. Finally, we use a Bayesian synthesis inversion to optimize CO from WRF-Chem using regionally tagged CO tracers. We multiply the characteristic ratios we derived with the optimized CO to obtain BC distributions. Our initial results suggest that the maximum ratios of BC versus CO occur in the western US during the summer (average: 4 ng/m3/ppbv) and in the southeast during the winter (average: 5 ng/m3/ppbv). However, we find that these relationships vary in space and time and are highly dependent on fuel usage and meteorology. We find that optimizing CO using EPA-AQS provides improvements in BC but only over areas where BC/CO ratios are close

  19. Using Q-Chem on the Peregrine System | High-Performance Computing | NREL

    Science.gov Websites

    initio quantum chemistry package with special strengths in excited state methods, non-adiabatic coupling , solvation models, explicitly correlated wavefunction methods, and cutting-edge DFT. Running Q-Chem on

  20. Viewing Spark Generated by ChemCam Laser for Mars Rover

    NASA Image and Video Library

    2010-09-21

    The ChemCam instrument for NASA Mars Science Laboratory mission uses a pulsed laser beam to vaporize a pinhead-size target, producing a flash of light from the ionized material plasma that can be analyzed to identify chemical elements in the target.

  1. 77 FR 47427 - Accreditation and Approval of Chem Gas International LLC, as a Commercial Gauger and Laboratory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-08

    ... Chem Gas International LLC, as a Commercial Gauger and Laboratory AGENCY: U.S. Customs and Border Protection, Department of Homeland Security. ACTION: Notice of accreditation and approval of Chem Gas... Gas International LLC, as commercial gauger and laboratory became effective on October 19, 2011. The...

  2. ChemNet: A Transferable and Generalizable Deep Neural Network for Small-Molecule Property Prediction

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Goh, Garrett B.; Siegel, Charles M.; Vishnu, Abhinav

    With access to large datasets, deep neural networks through representation learning have been able to identify patterns from raw data, achieving human-level accuracy in image and speech recognition tasks. However, in chemistry, availability of large standardized and labelled datasets is scarce, and with a multitude of chemical properties of interest, chemical data is inherently small and fragmented. In this work, we explore transfer learning techniques in conjunction with the existing Chemception CNN model, to create a transferable and generalizable deep neural network for small-molecule property prediction. Our latest model, ChemNet learns in a semi-supervised manner from inexpensive labels computed frommore » the ChEMBL database. When fine-tuned to the Tox21, HIV and FreeSolv dataset, which are 3 separate chemical tasks that ChemNet was not originally trained on, we demonstrate that ChemNet exceeds the performance of existing Chemception models, contemporary MLP models that trains on molecular fingerprints, and it matches the performance of the ConvGraph algorithm, the current state-of-the-art. Furthermore, as ChemNet has been pre-trained on a large diverse chemical database, it can be used as a universal “plug-and-play” deep neural network, which accelerates the deployment of deep neural networks for the prediction of novel small-molecule chemical properties.« less

  3. Sensitivity of WRF-chem predictions to dust source function specification in West Asia

    NASA Astrophysics Data System (ADS)

    Nabavi, Seyed Omid; Haimberger, Leopold; Samimi, Cyrus

    2017-02-01

    Dust storms tend to form in sparsely populated areas covered by only few observations. Dust source maps, known as source functions, are used in dust models to allocate a certain potential of dust release to each place. Recent research showed that the well known Ginoux source function (GSF), currently used in Weather Research and Forecasting Model coupled with Chemistry (WRF-chem), exhibits large errors over some regions in West Asia, particularly near the IRAQ/Syrian border. This study aims to improve the specification of this critical part of dust forecasts. A new source function based on multi-year analysis of satellite observations, called West Asia source function (WASF), is therefore proposed to raise the quality of WRF-chem predictions in the region. WASF has been implemented in three dust schemes of WRF-chem. Remotely sensed and ground-based observations have been used to verify the horizontal and vertical extent and location of simulated dust clouds. Results indicate that WRF-chem performance is significantly improved in many areas after the implementation of WASF. The modified runs (long term simulations over the summers 2008-2012, using nudging) have yielded an average increase of Spearman correlation between observed and forecast aerosol optical thickness by 12-16 percent points compared to control runs with standard source functions. They even outperform MACC and DREAM dust simulations over many dust source regions. However, the quality of the forecasts decreased with distance from sources, probably due to deficiencies in the transport and deposition characteristics of the forecast model in these areas.

  4. Curiosity ChemCam Finds High-Silica Mars Rocks

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Frydenvang, Jens

    A team of scientists, including one from Los Alamos National Laboratory, has found much higher concentrations of silica at some sites the Curiosity rover has investigated in the past seven months than anywhere else it has visited since landing on Mars 40 months ago. The first discovery was as Curiosity approached the area “Marias Pass,” where a lower geological unit contacts an overlying one. ChemCam, the rover’s laser-firing instrument for checking rock composition from a distance, detected bountiful silica in some targets the rover passed along the way to the contact zone. The ChemCam instrument was developed at Los Alamosmore » in partnership with the French IRAP laboratory in Toulouse and the French Space Agency. “The high silica was a surprise,” said Jens Frydenvang of Los Alamos National Laboratory and the University of Copenhagen, also a Curiosity science team member. “While we’re still working with multiple hypotheses on how the silica got so enriched, these hypotheses all require considerable water activity, and on Earth high silica deposits are often associated with environments that provide excellent support for microbial life. Because of this, the science team agreed to make a rare backtrack to investigate it more.”« less

  5. WRF-Chem Model Simulations of Arizona Dust Storms

    NASA Astrophysics Data System (ADS)

    Mohebbi, A.; Chang, H. I.; Hondula, D.

    2017-12-01

    The online Weather Research and Forecasting model with coupled chemistry module (WRF-Chem) is applied to simulate the transport, deposition and emission of the dust aerosols in an intense dust outbreak event that took place on July 5th, 2011 over Arizona. Goddard Chemistry Aerosol Radiation and Transport (GOCART), Air Force Weather Agency (AFWA), and University of Cologne (UoC) parameterization schemes for dust emission were evaluated. The model was found to simulate well the synoptic meteorological conditions also widely documented in previous studies. The chemistry module performance in reproducing the atmospheric desert dust load was evaluated using the horizontal field of the Aerosol Optical Depth (AOD) from Moderate Resolution Imaging Spectro (MODIS) radiometer Terra/Aqua and Aerosol Robotic Network (AERONET) satellites employing standard Dark Target (DT) and Deep Blue (DB) algorithms. To assess the temporal variability of the dust storm, Particulate Matter mass concentration data (PM10 and PM2.5) from Arizona Department of Environmental Quality (AZDEQ) ground-based air quality stations were used. The promising performance of WRF-Chem indicate that the model is capable of simulating the right timing and loading of a dust event in the planetary-boundary-layer (PBL) which can be used to forecast approaching severe dust events and to communicate an effective early warning.

  6. Justin B. Sluiter | NREL

    Science.gov Websites

    the published methods to increase LAP applicability. The adaptations must be tested to ensure the same concentrations must approximate the corresponding sugar concentrations in the sample. Methods for optimizing ;Compositional Analysis of Lignocellulosic Feedstocks. 1. Review and Description of Methods," J. Agric. Food

  7. EarthChem and SESAR: Data Resources and Interoperability for EarthScope Cyberinfrastructure

    NASA Astrophysics Data System (ADS)

    Lehnert, K. A.; Walker, D.; Block, K.; Vinay, S.; Ash, J.

    2008-12-01

    Data management within the EarthScope Cyberinfrastructure needs to pursue two goals in order to advance and maximize the broad scientific application and impact of the large volumes of observational data acquired by EarthScope facilities: (a) to provide access to all data acquired by EarthScope facilities, and to promote their use by broad audiences, and (b) to facilitate discovery of, access to, and integration of multi-disciplinary data sets that complement EarthScope data in support of EarthScope science. EarthChem and SESAR, the System for Earth Sample Registration, are two projects within the Geoinformatics for Geochemistry program that offer resources for EarthScope CI. EarthChem operates a data portal that currently provides access to >13 million analytical values for >600,000 samples, more than half of which are from North America, including data from the USGS and all data from the NAVDAT database, a web-accessible repository for age, chemical and isotopic data from Mesozoic and younger igneous rocks in western North America. The new EarthChem GEOCHRON database will house data collected in association with GeoEarthScope, storing and serving geochronological data submitted by participating facilities. The EarthChem Deep Lithosphere Dataset is a compilation of petrological data for mantle xenoliths, initiated in collaboration with GeoFrame to complement geophysical endeavors within EarthScope science. The EarthChem Geochemical Resource Library provides a home for geochemical and petrological data products and data sets. Parts of the digital data in EarthScope CI refer to physical samples such as drill cores, igneous rocks, or water and gas samples, collected, for example, by SAFOD or by EarthScope science projects and acquired through lab-based analysis. Management of sample-based data requires the use of global unique identifiers for samples, so that distributed data for individual samples generated in different labs and published in different papers can be

  8. Managing the computational chemistry big data problem: the ioChem-BD platform.

    PubMed

    Álvarez-Moreno, M; de Graaf, C; López, N; Maseras, F; Poblet, J M; Bo, C

    2015-01-26

    We present the ioChem-BD platform ( www.iochem-bd.org ) as a multiheaded tool aimed to manage large volumes of quantum chemistry results from a diverse group of already common simulation packages. The platform has an extensible structure. The key modules managing the main tasks are to (i) upload of output files from common computational chemistry packages, (ii) extract meaningful data from the results, and (iii) generate output summaries in user-friendly formats. A heavy use of the Chemical Mark-up Language (CML) is made in the intermediate files used by ioChem-BD. From them and using XSL techniques, we manipulate and transform such chemical data sets to fulfill researchers' needs in the form of HTML5 reports, supporting information, and other research media.

  9. The semantics of Chemical Markup Language (CML) for computational chemistry : CompChem.

    PubMed

    Phadungsukanan, Weerapong; Kraft, Markus; Townsend, Joe A; Murray-Rust, Peter

    2012-08-07

    : This paper introduces a subdomain chemistry format for storing computational chemistry data called CompChem. It has been developed based on the design, concepts and methodologies of Chemical Markup Language (CML) by adding computational chemistry semantics on top of the CML Schema. The format allows a wide range of ab initio quantum chemistry calculations of individual molecules to be stored. These calculations include, for example, single point energy calculation, molecular geometry optimization, and vibrational frequency analysis. The paper also describes the supporting infrastructure, such as processing software, dictionaries, validation tools and database repositories. In addition, some of the challenges and difficulties in developing common computational chemistry dictionaries are discussed. The uses of CompChem are illustrated by two practical applications.

  10. The semantics of Chemical Markup Language (CML) for computational chemistry : CompChem

    PubMed Central

    2012-01-01

    This paper introduces a subdomain chemistry format for storing computational chemistry data called CompChem. It has been developed based on the design, concepts and methodologies of Chemical Markup Language (CML) by adding computational chemistry semantics on top of the CML Schema. The format allows a wide range of ab initio quantum chemistry calculations of individual molecules to be stored. These calculations include, for example, single point energy calculation, molecular geometry optimization, and vibrational frequency analysis. The paper also describes the supporting infrastructure, such as processing software, dictionaries, validation tools and database repositories. In addition, some of the challenges and difficulties in developing common computational chemistry dictionaries are discussed. The uses of CompChem are illustrated by two practical applications. PMID:22870956

  11. ConfChem Conference on Select 2016 BCCE Presentations: Radical Awakenings--A New Teaching Paradigm Using Social Media

    ERIC Educational Resources Information Center

    Sorensen-Unruh, Clarissa

    2017-01-01

    This Communication summarizes one of the invited papers to the Select 2016 BCCE Presentations ACS CHED Committee on Computers in Chemical Education online ConfChem held from October 30 to November 22, 2016. The ConfChem paper (included within Supporting Information) focuses on the results of one instructor's incorporation of social media into her…

  12. WebChem Viewer: a tool for the easy dissemination of chemical and structural data sets

    PubMed Central

    2014-01-01

    Background Sharing sets of chemical data (e.g., chemical properties, docking scores, etc.) among collaborators with diverse skill sets is a common task in computer-aided drug design and medicinal chemistry. The ability to associate this data with images of the relevant molecular structures greatly facilitates scientific communication. There is a need for a simple, free, open-source program that can automatically export aggregated reports of entire chemical data sets to files viewable on any computer, regardless of the operating system and without requiring the installation of additional software. Results We here present a program called WebChem Viewer that automatically generates these types of highly portable reports. Furthermore, in designing WebChem Viewer we have also created a useful online web application for remotely generating molecular structures from SMILES strings. We encourage the direct use of this online application as well as its incorporation into other software packages. Conclusions With these features, WebChem Viewer enables interdisciplinary collaborations that require the sharing and visualization of small molecule structures and associated sets of heterogeneous chemical data. The program is released under the FreeBSD license and can be downloaded from http://nbcr.ucsd.edu/WebChemViewer. The associated web application (called “Smiley2png 1.0”) can be accessed through freely available web services provided by the National Biomedical Computation Resource at http://nbcr.ucsd.edu. PMID:24886360

  13. Tropospheric Emission Spectrometer (TES) for the Earth Observing System (EOS) CHEM Satellite

    NASA Technical Reports Server (NTRS)

    Beer, R.; Glavich, T.; Rider, D.

    2000-01-01

    The Tropospheric Emission Spectrometer (TES) is an imaging infrared Fourier transform spectrometer scheduled to be launched into polar sun-synchronous orbit on the Earth Observing System (EOS) CHEM satellite in December 2002.

  14. Interactive Gaussian Graphical Models for Discovering Depth Trends in ChemCam Data

    NASA Astrophysics Data System (ADS)

    Oyen, D. A.; Komurlu, C.; Lanza, N. L.

    2018-04-01

    Interactive Gaussian graphical models discover surface compositional features on rocks in ChemCam targets. Our approach visualizes shot-to-shot relationships among LIBS observations, and identifies the wavelengths involved in the trend.

  15. Curiosity ChemCam Finds High-Silica Mars Rocks

    ScienceCinema

    Frydenvang, Jens

    2018-01-16

    A team of scientists, including one from Los Alamos National Laboratory, has found much higher concentrations of silica at some sites the Curiosity rover has investigated in the past seven months than anywhere else it has visited since landing on Mars 40 months ago. The first discovery was as Curiosity approached the area “Marias Pass,” where a lower geological unit contacts an overlying one. ChemCam, the rover’s laser-firing instrument for checking rock composition from a distance, detected bountiful silica in some targets the rover passed along the way to the contact zone. The ChemCam instrument was developed at Los Alamos in partnership with the French IRAP laboratory in Toulouse and the French Space Agency. “The high silica was a surprise,” said Jens Frydenvang of Los Alamos National Laboratory and the University of Copenhagen, also a Curiosity science team member. “While we’re still working with multiple hypotheses on how the silica got so enriched, these hypotheses all require considerable water activity, and on Earth high silica deposits are often associated with environments that provide excellent support for microbial life. Because of this, the science team agreed to make a rare backtrack to investigate it more.”

  16. Incorporation of a Chemical Equilibrium Equation of State into LOCI-Chem

    NASA Technical Reports Server (NTRS)

    Cox, Carey F.

    2005-01-01

    Renewed interest in development of advanced high-speed transport, reentry vehicles and propulsion systems has led to a resurgence of research into high speed aerodynamics. As this flow regime is typically dominated by hot reacting gaseous flow, efficient models for the characteristic chemical activity are necessary for accurate and cost effective analysis and design of aerodynamic vehicles that transit this regime. The LOCI-Chem code recently developed by Ed Luke at Mississippi State University for NASA/MSFC and used by NASA/MSFC and SSC represents an important step in providing an accurate, efficient computational tool for the simulation of reacting flows through the use of finite-rate kinetics [3]. Finite rate chemistry however, requires the solution of an additional N-1 species mass conservation equations with source terms involving reaction kinetics that are not fully understood. In the equilibrium limit, where the reaction rates approach infinity, these equations become very stiff. Through the use of the assumption of local chemical equilibrium the set of governing equations is reduced back to the usual gas dynamic equations, and thus requires less computation, while still allowing for the inclusion of reacting flow phenomenology. The incorporation of a chemical equilibrium equation of state module into the LOCI-Chem code was the primary objective of the current research. The major goals of the project were: (1) the development of a chemical equilibrium composition solver, and (2) the incorporation of chemical equilibrium solver into LOCI-Chem. Due to time and resource constraints, code optimization was not considered unless it was important to the proper functioning of the code.

  17. Regional modelling of polycyclic aromatic hydrocarbons: WRF-Chem-PAH model development and East Asia case studies

    NASA Astrophysics Data System (ADS)

    Mu, Qing; Lammel, Gerhard; Gencarelli, Christian N.; Hedgecock, Ian M.; Chen, Ying; Přibylová, Petra; Teich, Monique; Zhang, Yuxuan; Zheng, Guangjie; van Pinxteren, Dominik; Zhang, Qiang; Herrmann, Hartmut; Shiraiwa, Manabu; Spichtinger, Peter; Su, Hang; Pöschl, Ulrich; Cheng, Yafang

    2017-10-01

    Polycyclic aromatic hydrocarbons (PAHs) are hazardous pollutants, with increasing emissions in pace with economic development in East Asia, but their distribution and fate in the atmosphere are not yet well understood. We extended the regional atmospheric chemistry model WRF-Chem (Weather Research Forecast model with Chemistry module) to comprehensively study the atmospheric distribution and the fate of low-concentration, slowly degrading semivolatile compounds. The WRF-Chem-PAH model reflects the state-of-the-art understanding of current PAHs studies with several new or updated features. It was applied for PAHs covering a wide range of volatility and hydrophobicity, i.e. phenanthrene, chrysene and benzo[a]pyrene, in East Asia. Temporally highly resolved PAH concentrations and particulate mass fractions were evaluated against observations. The WRF-Chem-PAH model is able to reasonably well simulate the concentration levels and particulate mass fractions of PAHs near the sources and at a remote outflow region of East Asia, in high spatial and temporal resolutions. Sensitivity study shows that the heterogeneous reaction with ozone and the homogeneous reaction with the nitrate radical significantly influence the fate and distributions of PAHs. The methods to implement new species and to correct the transport problems can be applied to other newly implemented species in WRF-Chem.

  18. Diagenetic Features Analyzed by ChemCam/Curiosity at Pahrump Hills, Gale Crater, Mars

    NASA Technical Reports Server (NTRS)

    Nachon, M.; Mangold, N.; Cousin, A.; Forni, O.; Anderson, R. B.; Blank, J. G.; Calef, F.; Clegg, S.; Fabre, C.; Fisk, M.; hide

    2015-01-01

    Onboard the Mars Science Laboratory (MSL) Curiosity rover, the ChemCam instrument consists of : (1) a Laser-Induced Breakdown Spectrometer (LIBS) for elemental analysis of targets and (2) a Remote Micro Imager (RMI), which provides imaging context for the LIBS. The LIBS/ChemCam performs analysis typically of spot sizes 350-550 micrometers in diameter, up to 7 meters from the rover. Within Gale crater, Curiosity traveled from Bradbury Landing toward the base of Mount Sharp, reaching Pahrump Hills outcrop circa sol 750. This region, as seen from orbit, represents the first exposures of lower Mount Sharp. In this abstract we focus on two types of features present within the Pahrump Hills outcrop: concretion features and light-toned veins.

  19. ChemCam Compositional Results from the Shaler Outcrop in Gale Crater, Mars (Invited)

    NASA Astrophysics Data System (ADS)

    Anderson, R. B.; Leveille, R. J.; Vaniman, D.; Williams, J.; Clegg, S. M.; Le Mouelic, S.; Wiens, R. C.; Edgar, L. A.; Newsom, H. E.; Clark, B. C.; Ollila, A.; Lewis, K. W.; Gupta, S.; Team, M.

    2013-12-01

    The Curiosity rover first visited the outcrop known as 'Shaler' on Sol 121 of the mission. The ~1 m thick outcrop is the 'type section' for the Shaler member, which forms the uppermost part of the Yellowknife Bay formation. The Shaler outcrop exhibits multiple well-exposed cross-bedded facies with typical grain sizes of 1-2 mm, most consistent with fluvial deposition. Initial results from the two Sol 121 observations of Shaler by the ChemCam instrument showed similar composition, with a mix of mafic silicates and feldspar grains. A strong correlation between iron and titanium indicates the possible presence of titanomagnetite or ilmenite. CaO shows an anticorrelation with the total of the measured major elements, suggesting that it may be related to a non-silicate phase such as a salt. The rover returned to the outcrop on Sols 309-324. Because of the rugged nature of the outcrop, much of the exposed rock was not reachable by the rover's robotic arm. However, the ChemCam instrument can collect elemental compositional information out to a range of ~7 m using laser-induced breakdown spectroscopy (LIBS), and can acquire high-resolution images at even greater range. ChemCam analyzed 29 locations using LIBS to determine chemical composition, and four additional locations were imaged with the Remote Micro Imager. The targets analyzed included both fine- and coarse-grained facies, as well as a distinct upper unit which appears darker and less red than other Shaler units in Mastcam images, and lacks the striking alternating resistant and recessive cross-bedding observed in lower Shaler. This upper unit occurs at an elevation similar to the rocks at 'Rocknest', and similar-looking rocks appear across the cratered surface to the south and east of Shaler. Several blocks apparently derived from this upper unit were analyzed by ChemCam to test the hypothesis that the unit is related to rocks observed at Rocknest. Work is ongoing to interpret the results of the ChemCam campaign

  20. Implementing marine organic aerosols into the GEOS-Chem model

    DOE PAGES

    Gantt, B.; Johnson, M. S.; Crippa, M.; ...

    2015-03-17

    Marine-sourced organic aerosols (MOAs) have been shown to play an important role in tropospheric chemistry by impacting surface mass, cloud condensation nuclei, and ice nuclei concentrations over remote marine and coastal regions. In this work, an online marine primary organic aerosol emission parameterization, designed to be used for both global and regional models, was implemented into the GEOS-Chem (Global Earth Observing System Chemistry) model. The implemented emission scheme improved the large underprediction of organic aerosol concentrations in clean marine regions (normalized mean bias decreases from -79% when using the default settings to -12% when marine organic aerosols are added). Modelmore » predictions were also in good agreement (correlation coefficient of 0.62 and normalized mean bias of -36%) with hourly surface concentrations of MOAs observed during the summertime at an inland site near Paris, France. Our study shows that MOAs have weaker coastal-to-inland concentration gradients than sea-salt aerosols, leading to several inland European cities having >10% of their surface submicron organic aerosol mass concentration with a marine source. The addition of MOA tracers to GEOS-Chem enabled us to identify the regions with large contributions of freshly emitted or aged aerosol having distinct physicochemical properties, potentially indicating optimal locations for future field studies.« less

  1. Implementing Marine Organic Aerosols Into the GEOS-Chem Model

    NASA Technical Reports Server (NTRS)

    Johnson, Matthew S.

    2015-01-01

    Marine-sourced organic aerosols (MOA) have been shown to play an important role in tropospheric chemistry by impacting surface mass, cloud condensation nuclei, and ice nuclei concentrations over remote marine and coastal regions. In this work, an online marine primary organic aerosol emission parameterization, designed to be used for both global and regional models, was implemented into the GEOS-Chem model. The implemented emission scheme improved the large under-prediction of organic aerosol concentrations in clean marine regions (normalized mean bias decreases from -79% when using the default settings to -12% when marine organic aerosols are added). Model predictions were also in good agreement (correlation coefficient of 0.62 and normalized mean bias of -36%) with hourly surface concentrations of MOA observed during the summertime at an inland site near Paris, France. Our study shows that MOA have weaker coastal-to-inland concentration gradients than sea-salt aerosols, leading to several inland European cities having > 10% of their surface submicron organic aerosol mass concentration with a marine source. The addition of MOA tracers to GEOS-Chem enabled us to identify the regions with large contributions of freshly-emitted or aged aerosol having distinct physicochemical properties, potentially indicating optimal locations for future field studies.

  2. pH-dependent interaction of rhodopsin with cyanidin-3-glucoside. 2. Functional aspects.

    PubMed

    Tirupula, Kalyan C; Balem, Fernanda; Yanamala, Naveena; Klein-Seetharaman, Judith

    2009-01-01

    Anthocyanins are a class of phytochemicals that confer color to flowers, fruits, vegetables and leaves. They are part of our regular diet and serve as dietary supplements because of numerous health benefits, including improved vision. Recent studies have shown that the anthocyanin cyanidin-3-O-glucoside (C3G) increased regeneration of the dim-light photoreceptor rhodopsin (Matsumoto et al. [2003] J. Agric. Food Chem., 51, 3560-3563). In an accompanying study (Yanamala et al. [2009] Photochem. Photobiol.), we show that C3G directly binds to rhodopsin in a pH-dependent manner. In this study, we investigated the functional consequences of C3G binding to rhodopsin. As observed previously in rod outer segments, regeneration of purified rhodopsin in detergent micelles is also accelerated in the presence of C3G. Thermal denaturation and stability studies using circular dichroism, fluorescence and UV/visible absorbance spectroscopy show that C3G exerts a destabilizing effect on rhodopsin structure while it only modestly alters G-protein activation and the rates at which the light-activated Metarhodopsin II state decays to opsin and free retinal. These results indicate that the mechanism of C3G-enhanced regeneration may be based on changes in opsin structure promoting access to the retinal binding pocket.

  3. A New WRF-Chem Treatment for Studying Regional Scale Impacts of Cloud-Aerosol Interactions in Parameterized Cumuli

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Berg, Larry K.; Shrivastava, ManishKumar B.; Easter, Richard C.

    A new treatment of cloud-aerosol interactions within parameterized shallow and deep convection has been implemented in WRF-Chem that can be used to better understand the aerosol lifecycle over regional to synoptic scales. The modifications to the model to represent cloud-aerosol interactions include treatment of the cloud dropletnumber mixing ratio; key cloud microphysical and macrophysical parameters (including the updraft fractional area, updraft and downdraft mass fluxes, and entrainment) averaged over the population of shallow clouds, or a single deep convective cloud; and vertical transport, activation/resuspension, aqueous chemistry, and wet removal of aerosol and trace gases in warm clouds. Thesechanges have beenmore » implemented in both the WRF-Chem chemistry packages as well as the Kain-Fritsch cumulus parameterization that has been modified to better represent shallow convective clouds. Preliminary testing of the modified WRF-Chem has been completed using observations from the Cumulus Humilis Aerosol Processing Study (CHAPS) as well as a high-resolution simulation that does not include parameterized convection. The simulation results are used to investigate the impact of cloud-aerosol interactions on the regional scale transport of black carbon (BC), organic aerosol (OA), and sulfate aerosol. Based on the simulations presented here, changes in the column integrated BC can be as large as -50% when cloud-aerosol interactions are considered (due largely to wet removal), or as large as +35% for sulfate in non-precipitating conditions due to the sulfate production in the parameterized clouds. The modifications to WRF-Chem version 3.2.1 are found to account for changes in the cloud drop number concentration (CDNC) and changes in the chemical composition of cloud-drop residuals in a way that is consistent with observations collected during CHAPS. Efforts are currently underway to port the changes described here to WRF-Chem version 3.5, and it is anticipated

  4. An investigation of methods for injecting emissions from boreal wildfires using WRF-Chem during ARCTAS

    NASA Astrophysics Data System (ADS)

    Sessions, W. R.; Fuelberg, H. E.; Kahn, R. A.; Winker, D. M.

    2010-11-01

    The Weather Research and Forecasting Model (WRF) is considered a "next generation" mesoscale meteorology model. The inclusion of a chemistry module (WRF-Chem) allows transport simulations of chemical and aerosol species such as those observed during NASA's Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) in 2008. The ARCTAS summer deployment phase during June and July coincided with large boreal wildfires in Saskatchewan and Eastern Russia. One of the most important aspects of simulating wildfire plume transport is the height at which emissions are injected. WRF-Chem contains an integrated one-dimensional plume rise model to determine the appropriate injection layer. The plume rise model accounts for thermal buoyancy associated with fires and the local atmospheric stability. This study compares results from the plume model against those of two more traditional injection methods: Injecting within the planetary boundary layer, and in a layer 3-5 km above ground level. Fire locations are satellite derived from the GOES Wildfire Automated Biomass Burning Algorithm (WF_ABBA) and the MODIS thermal hotspot detection. Two methods for preprocessing these fire data are compared: The prep_chem_sources method included with WRF-Chem, and the Naval Research Laboratory's Fire Locating and Monitoring of Burning Emissions (FLAMBE). Results from the simulations are compared with satellite-derived products from the AIRS, MISR and CALIOP sensors. Results show that the FLAMBE pre-processor produces more realistic injection heights than does prep_chem_sources. The plume rise model using FLAMBE provides the best agreement with satellite-observed injection heights. Conversely, when the planetary boundary layer or the 3-5 km AGL layer were filled with emissions, the resulting injection heights exhibit less agreement with observed plume heights. Results indicate that differences in injection heights produce different transport pathways. These

  5. An investigation of methods for injecting emissions from boreal wildfires using WRF-Chem during ARCTAS

    NASA Astrophysics Data System (ADS)

    Sessions, W. R.; Fuelberg, H. E.; Kahn, R. A.; Winker, D. M.

    2011-06-01

    The Weather Research and Forecasting Model (WRF) is considered a "next generation" mesoscale meteorology model. The inclusion of a chemistry module (WRF-Chem) allows transport simulations of chemical and aerosol species such as those observed during NASA's Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) in 2008. The ARCTAS summer deployment phase during June and July coincided with large boreal wildfires in Saskatchewan and Eastern Russia. One of the most important aspects of simulating wildfire plume transport is the height at which emissions are injected. WRF-Chem contains an integrated one-dimensional plume rise model to determine the appropriate injection layer. The plume rise model accounts for thermal buoyancy associated with fires and local atmospheric stability. This paper describes a case study of a 10 day period during the Spring phase of ARCTAS. It compares results from the plume model against those of two more traditional injection methods: Injecting within the planetary boundary layer, and in a layer 3-5 km above ground level. Fire locations are satellite derived from the GOES Wildfire Automated Biomass Burning Algorithm (WF_ABBA) and the MODIS thermal hotspot detection. Two methods for preprocessing these fire data are compared: The prep_chem_sources method included with WRF-Chem, and the Naval Research Laboratory's Fire Locating and Monitoring of Burning Emissions (FLAMBE). Results from the simulations are compared with satellite-derived products from the AIRS, MISR and CALIOP sensors. When FLAMBE provides input to the 1-D plume rise model, the resulting injection heights exhibit the best agreement with satellite-observed injection heights. The FLAMBE-derived heights are more realistic than those utilizing prep_chem_sources. Conversely, when the planetary boundary layer or the 3-5 km a.g.l. layer were filled with emissions, the resulting injection heights exhibit less agreement with observed plume heights

  6. Development of a Grid-Independent Geos-Chem Chemical Transport Model (v9-02) as an Atmospheric Chemistry Module for Earth System Models

    NASA Technical Reports Server (NTRS)

    Long, M. S.; Yantosca, R.; Nielsen, J. E; Keller, C. A.; Da Silva, A.; Sulprizio, M. P.; Pawson, S.; Jacob, D. J.

    2015-01-01

    The GEOS-Chem global chemical transport model (CTM), used by a large atmospheric chemistry research community, has been re-engineered to also serve as an atmospheric chemistry module for Earth system models (ESMs). This was done using an Earth System Modeling Framework (ESMF) interface that operates independently of the GEOSChem scientific code, permitting the exact same GEOSChem code to be used as an ESM module or as a standalone CTM. In this manner, the continual stream of updates contributed by the CTM user community is automatically passed on to the ESM module, which remains state of science and referenced to the latest version of the standard GEOS-Chem CTM. A major step in this re-engineering was to make GEOS-Chem grid independent, i.e., capable of using any geophysical grid specified at run time. GEOS-Chem data sockets were also created for communication between modules and with external ESM code. The grid-independent, ESMF-compatible GEOS-Chem is now the standard version of the GEOS-Chem CTM. It has been implemented as an atmospheric chemistry module into the NASA GEOS- 5 ESM. The coupled GEOS-5-GEOS-Chem system was tested for scalability and performance with a tropospheric oxidant-aerosol simulation (120 coupled species, 66 transported tracers) using 48-240 cores and message-passing interface (MPI) distributed-memory parallelization. Numerical experiments demonstrate that the GEOS-Chem chemistry module scales efficiently for the number of cores tested, with no degradation as the number of cores increases. Although inclusion of atmospheric chemistry in ESMs is computationally expensive, the excellent scalability of the chemistry module means that the relative cost goes down with increasing number of cores in a massively parallel environment.

  7. Effect of MERRA-2 initial and boundary conditions on WRF-Chem aerosol simulations over the Arabian Peninsula

    NASA Astrophysics Data System (ADS)

    Ukhov, Alexander; Stenchikov, Georgiy

    2017-04-01

    In this study, we test the sensitivity of the horizontal and vertical distributions of aerosols to the initial and boundary conditions (IC&BC) of the aerosol/chemistry. We use the WRF-Chem model configured over the Arabian Peninsula to study both dust and anthropogenic aerosols. Currently, in the WRF-Chem the aerosol/chemistry IC&BC are constructed using either default aerosol/chemistry profiles with no inflow of aerosols and chemicals through the lateral boundaries or using the aerosol/chemistry fields from MOZART, the model for ozone and related chemical tracers from the NCAR. Here, we construct aerosol/chemistry IC&BC using MERRA-2 output. MERRA-2 is a recently developed reanalysis that assimilates ground-based and satellite observations to provide the improved distributions of aerosols and chemical species. We ran WRF-Chem simulations for July-August 2015 using GOCART/AFWA dust emission and GOCART aerosol schemes. We used the EDGAR HTAP V4 dataset to calculate SO2 emissions. Comparison of three runs initiated using the same ERA-Interim reanalysis fields but different aerosol/chemistry IC&BC (default WRF-Chem, MOZART, and MERRA-2) with AERONET, Micropulse Lidar, Balloon, and satellite observations shows that the MERRA-2 IC&BC are superior.

  8. Alkali trace elements in Gale crater, Mars, with ChemCam: Calibration update and geological implications

    NASA Astrophysics Data System (ADS)

    Payré, V.; Fabre, C.; Cousin, A.; Sautter, V.; Wiens, R. C.; Forni, O.; Gasnault, O.; Mangold, N.; Meslin, P.-Y.; Lasue, J.; Ollila, A.; Rapin, W.; Maurice, S.; Nachon, M.; Le Deit, L.; Lanza, N.; Clegg, S.

    2017-03-01

    The Chemistry Camera (ChemCam) instrument onboard Curiosity can detect minor and trace elements such as lithium, strontium, rubidium, and barium. Their abundances can provide some insights about Mars' magmatic history and sedimentary processes. We focus on developing new quantitative models for these elements by using a new laboratory database (more than 400 samples) that displays diverse compositions that are more relevant for Gale crater than the previous ChemCam database. These models are based on univariate calibration curves. For each element, the best model is selected depending on the results obtained by using the ChemCam calibration targets onboard Curiosity. New quantifications of Li, Sr, Rb, and Ba in Gale samples have been obtained for the first 1000 Martian days. Comparing these data in alkaline and magnesian rocks with the felsic and mafic clasts from the Martian meteorite NWA7533—from approximately the same geologic period—we observe a similar behavior: Sr, Rb, and Ba are more concentrated in soluble- and incompatible-element-rich mineral phases (Si, Al, and alkali-rich). Correlations between these trace elements and potassium in materials analyzed by ChemCam reveal a strong affinity with K-bearing phases such as feldspars, K-phyllosilicates, and potentially micas in igneous and sedimentary rocks. However, lithium is found in comparable abundances in alkali-rich and magnesium-rich Gale rocks. This very soluble element can be associated with both alkali and Mg-Fe phases such as pyroxene and feldspar. These observations of Li, Sr, Rb, and Ba mineralogical associations highlight their substitution with potassium and their incompatibility in magmatic melts.

  9. Introduction to the Spring 2014 ConfChem on the Flipped Classroom

    ERIC Educational Resources Information Center

    Luker, Chris; Muzyka, Jennifer; Belford, Robert

    2015-01-01

    Students' active engagement is one of the most critical challenges to any successful learning environment. The blending of active engagement along with rich, meaningful content is necessary for chemical educators to re-examine the purpose of the chemistry classroom. The Spring 2014 ConfChem conference, Flipped Classroom, was held from May 9 to…

  10. Application of distance correction to ChemCam laser-induced breakdown spectroscopy measurements

    DOE PAGES

    Mezzacappa, A.; Melikechi, N.; Cousin, A.; ...

    2016-04-04

    Laser-induced breakdown spectroscopy (LIBS) provides chemical information from atomic, ionic, and molecular emissions from which geochemical composition can be deciphered. Analysis of LIBS spectra in cases where targets are observed at different distances, as is the case for the ChemCam instrument on the Mars rover Curiosity, which performs analyses at distances between 2 and 7.4 m is not a simple task. Previously, we showed that spectral distance correction based on a proxy spectroscopic standard created from first-shot dust observations on Mars targets ameliorates the distance bias in multivariate-based elemental-composition predictions of laboratory data. In this work, we correct an expandedmore » set of neutral and ionic spectral emissions for distance bias in the ChemCam data set. By using and testing different selection criteria to generate multiple proxy standards, we find a correction that minimizes the difference in spectral intensity measured at two different distances and increases spectral reproducibility. When the quantitative performance of distance correction is assessed, there is improvement for SiO 2, Al 2O 3, CaO, FeOT, Na 2O, K 2O, that is, for most of the major rock forming elements, and for the total major-element weight percent predicted. But, for MgO the method does not provide improvements while for TiO 2, it yields inconsistent results. Additionally, we observed that many emission lines do not behave consistently with distance, evidenced from laboratory analogue measurements and ChemCam data. This limits the effectiveness of the method.« less

  11. ChemBrowser: a flexible framework for mining chemical documents.

    PubMed

    Wu, Xian; Zhang, Li; Chen, Ying; Rhodes, James; Griffin, Thomas D; Boyer, Stephen K; Alba, Alfredo; Cai, Keke

    2010-01-01

    The ability to extract chemical and biological entities and relations from text documents automatically has great value to biochemical research and development activities. The growing maturity of text mining and artificial intelligence technologies shows promise in enabling such automatic chemical entity extraction capabilities (called "Chemical Annotation" in this paper). Many techniques have been reported in the literature, ranging from dictionary and rule-based techniques to machine learning approaches. In practice, we found that no single technique works well in all cases. A combinatorial approach that allows one to quickly compose different annotation techniques together for a given situation is most effective. In this paper, we describe the key challenges we face in real-world chemical annotation scenarios. We then present a solution called ChemBrowser which has a flexible framework for chemical annotation. ChemBrowser includes a suite of customizable processing units that might be utilized in a chemical annotator, a high-level language that describes the composition of various processing units that would form a chemical annotator, and an execution engine that translates the composition language to an actual annotator that can generate annotation results for a given set of documents. We demonstrate the impact of this approach by tailoring an annotator for extracting chemical names from patent documents and show how this annotator can be easily modified with simple configuration alone.

  12. PubChem BioAssay: A Decade's Development toward Open High-Throughput Screening Data Sharing.

    PubMed

    Wang, Yanli; Cheng, Tiejun; Bryant, Stephen H

    2017-07-01

    High-throughput screening (HTS) is now routinely conducted for drug discovery by both pharmaceutical companies and screening centers at academic institutions and universities. Rapid advance in assay development, robot automation, and computer technology has led to the generation of terabytes of data in screening laboratories. Despite the technology development toward HTS productivity, fewer efforts were devoted to HTS data integration and sharing. As a result, the huge amount of HTS data was rarely made available to the public. To fill this gap, the PubChem BioAssay database ( https://www.ncbi.nlm.nih.gov/pcassay/ ) was set up in 2004 to provide open access to the screening results tested on chemicals and RNAi reagents. With more than 10 years' development and contributions from the community, PubChem has now become the largest public repository for chemical structures and biological data, which provides an information platform to worldwide researchers supporting drug development, medicinal chemistry study, and chemical biology research. This work presents a review of the HTS data content in the PubChem BioAssay database and the progress of data deposition to stimulate knowledge discovery and data sharing. It also provides a description of the database's data standard and basic utilities facilitating information access and use for new users.

  13. ChemCam results from the Shaler Outcrop in Gale Crater, Mars

    USGS Publications Warehouse

    Anderson, Ryan Bradley; Edgar, L.; Bridges, J.C.; Williams, A.; Williams, J.; Ollila, A.; Forni, O.; Mangold, N.; Lanza, N.; Sautter, V.; Gupta, S.; Blaney, D.; Clark, B.; Clegg, G.; Dromart, G.; Gasnault, O.; Lasue, J.; Le Mouélic, S.; Léveillé, Richard; Lewin, E.; Lewis, K.; Maurice, S.; Nachon, Marion; Newsom, H.; Vaniman, D.; Wiens, R.C.

    2014-01-01

    The "Shaler" outcrop in Gale crater is approximately 0.7 m thick and >20 m long, and exhibits multiple well-exposed platy and cross-stratified facies [1] interpreted to be primarily fluvial sandstone deposits. The outcrop is a part of the upper Glenelg member in the Yellowknife Bay (YKB) stratigraphic section [2]. Curiosity first encountered the "Shaler" outcrop on sol 121 of the mission, and returned to the outcrop on sols 309- 324. The rugged nature of the outcrop and short time available for analysis limited opportunities for contact science, but ChemCam’s ability to remotely collect compositional and textural observations resulted in a large data set from Shaler. ChemCam conducted analyses of 29 non-soil targets at Shaler, 26 of which used laser-induced breakdown spectroscopy (LIBS) for a total of 9,180 spectra. Three observations used only the remote micro-imager (RMI). Each of the 26 LIBS targets were analyzed at between 5 and 25 points, providing a measure of the target homogeneity and in some cases transecting fine strata. 

  14. Retrieval of water vapor column abundance and aerosol properties from ChemCam passive sky spectroscopy

    NASA Astrophysics Data System (ADS)

    McConnochie, Timothy H.; Smith, Michael D.; Wolff, Michael J.; Bender, Steve; Lemmon, Mark; Wiens, Roger C.; Maurice, Sylvestre; Gasnault, Olivier; Lasue, Jeremie; Meslin, Pierre-Yves; Harri, Ari-Matti; Genzer, Maria; Kemppinen, Osku; Martínez, Germán M.; DeFlores, Lauren; Blaney, Diana; Johnson, Jeffrey R.; Bell, James F.

    2018-06-01

    We derive water vapor column abundances and aerosol properties from Mars Science Laboratory (MSL) ChemCam passive mode observations of scattered sky light. This paper covers the methodology and initial results for water vapor and also provides preliminary results for aerosols. The data set presented here includes the results of 113 observations spanning from Mars Year 31 Ls = 291° (March 30, 2013) to Mars Year 33 Ls= 127° (March 24, 2016). Each ChemCam passive sky observation acquires spectra at two different elevation angles. We fit these spectra with a discrete-ordinates multiple scattering radiative transfer model, using the correlated-k approximation for gas absorption bands. The retrieval proceeds by first fitting the continuum of the ratio of the two elevation angles to solve for aerosol properties, and then fitting the continuum-removed ratio to solve for gas abundances. The final step of the retrieval makes use of the observed CO2 absorptions and the known CO2 abundance to correct the retrieved water vapor abundance for the effects of the vertical distribution of scattering aerosols and to derive an aerosol scale height parameter. Our water vapor results give water vapor column abundance with a precision of ±0.6 precipitable microns and systematic errors no larger than ±0.3 precipitable microns, assuming uniform vertical mixing. The ChemCam-retrieved water abundances show, with only a few exceptions, the same seasonal behavior and the same timing of seasonal minima and maxima as the TES, CRISM, and REMS-H data sets that we compare them to. However ChemCam-retrieved water abundances are generally lower than zonal and regional scale from-orbit water vapor data, while at the same time being significantly larger than pre-dawn REMS-H abundances. Pending further analysis of REMS-H volume mixing ratio uncertainties, the differences between ChemCam and REMS-H pre-dawn mixing ratios appear to be much too large to be explained by large scale circulations and thus

  15. Alkali trace elements in Gale crater, Mars, with ChemCam: Calibration update and geological implications

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Payre, Valerie; Fabre, Cecile; Cousin, Agnes

    The Chemistry Camera (ChemCam) instrument onboard Curiosity can detect minor and trace elements such as lithium, strontium, rubidium, and barium. Their abundances can provide some insights about Mars' magmatic history and sedimentary processes. We focus on developing new quantitative models for these elements by using a new laboratory database (more than 400 samples) that displays diverse compositions that are more relevant for Gale crater than the previous ChemCam database. These models are based on univariate calibration curves. For each element, the best model is selected depending on the results obtained by using the ChemCam calibration targets onboard Curiosity. New quantificationsmore » of Li, Sr, Rb, and Ba in Gale samples have been obtained for the first 1000 Martian days. Comparing these data in alkaline and magnesian rocks with the felsic and mafic clasts from the Martian meteorite NWA7533—from approximately the same geologic period—we observe a similar behavior: Sr, Rb, and Ba are more concentrated in soluble- and incompatible-element-rich mineral phases (Si, Al, and alkali-rich). Correlations between these trace elements and potassium in materials analyzed by ChemCam reveal a strong affinity with K-bearing phases such as feldspars, K-phyllosilicates, and potentially micas in igneous and sedimentary rocks. However, lithium is found in comparable abundances in alkali-rich and magnesium-rich Gale rocks. This very soluble element can be associated with both alkali and Mg-Fe phases such as pyroxene and feldspar. Here, these observations of Li, Sr, Rb, and Ba mineralogical associations highlight their substitution with potassium and their incompatibility in magmatic melts.« less

  16. Alkali trace elements in Gale crater, Mars, with ChemCam: Calibration update and geological implications

    DOE PAGES

    Payre, Valerie; Fabre, Cecile; Cousin, Agnes; ...

    2017-03-20

    The Chemistry Camera (ChemCam) instrument onboard Curiosity can detect minor and trace elements such as lithium, strontium, rubidium, and barium. Their abundances can provide some insights about Mars' magmatic history and sedimentary processes. We focus on developing new quantitative models for these elements by using a new laboratory database (more than 400 samples) that displays diverse compositions that are more relevant for Gale crater than the previous ChemCam database. These models are based on univariate calibration curves. For each element, the best model is selected depending on the results obtained by using the ChemCam calibration targets onboard Curiosity. New quantificationsmore » of Li, Sr, Rb, and Ba in Gale samples have been obtained for the first 1000 Martian days. Comparing these data in alkaline and magnesian rocks with the felsic and mafic clasts from the Martian meteorite NWA7533—from approximately the same geologic period—we observe a similar behavior: Sr, Rb, and Ba are more concentrated in soluble- and incompatible-element-rich mineral phases (Si, Al, and alkali-rich). Correlations between these trace elements and potassium in materials analyzed by ChemCam reveal a strong affinity with K-bearing phases such as feldspars, K-phyllosilicates, and potentially micas in igneous and sedimentary rocks. However, lithium is found in comparable abundances in alkali-rich and magnesium-rich Gale rocks. This very soluble element can be associated with both alkali and Mg-Fe phases such as pyroxene and feldspar. Here, these observations of Li, Sr, Rb, and Ba mineralogical associations highlight their substitution with potassium and their incompatibility in magmatic melts.« less

  17. Evaluation of a regional assimilation system coupled with the WRF-chem model

    NASA Astrophysics Data System (ADS)

    Liu, Yan-an; Gao, Wei; Huang, Hung-lung; Strabala, Kathleen; Liu, Chaoshun; Shi, Runhe

    2013-09-01

    Air quality has become a social issue that is causing great concern to humankind across the globe, but particularly in developing countries. Even though the Weather Research and Forecasting with Chemistry (WRF-Chem) model has been applied in many regions, the resolution for inputting meteorology field analysis still impacts the accuracy of forecast. This article describes the application of the CIMSS Regional Assimilation System (CRAS) in East China, and its capability to assimilate the direct broadcast (DB) satellite data for obtaining more detailed meteorological information, including cloud top pressure (CTP) and total precipitation water (TPW) from MODIS. Performance evaluation of CRAS is based on qualitative and quantitative analyses. Compared with data collected from ERA-Interim, Radiosonde, and the Tropical Rainfall Measuring Mission (TRMM) precipitation measurements using bias and Root Mean Square Error (RMSE), CRAS has a systematic error due to the impact of topography and other factors; however, the forecast accuracy of all elements in the model center area is higher at various levels. The bias computed with Radiosonde reveals that the temperature and geopotential height of CRAS are better than ERA-Interim at first guess. Moreover, the location of the 24 h accumulated precipitation forecast are highly consistent with the TRMM retrieval precipitation, which means that the performance of CRAS is excellent. In summation, the newly built Vtable can realize the function of inputting the meteorology field from CRAS output into WRF, which couples the CRAS with WRF-Chem. Therefore, this study not only provides for forecast accuracy of CRAS, but also increases the capability of running the WRF-Chem model at higher resolutions in the future.

  18. PubChem3D: Shape compatibility filtering using molecular shape quadrupoles

    PubMed Central

    2011-01-01

    Background PubChem provides a 3-D neighboring relationship, which involves finding the maximal shape overlap between two static compound 3-D conformations, a computationally intensive step. It is highly desirable to avoid this overlap computation, especially if it can be determined with certainty that a conformer pair cannot meet the criteria to be a 3-D neighbor. As such, PubChem employs a series of pre-filters, based on the concept of volume, to remove approximately 65% of all conformer neighbor pairs prior to shape overlap optimization. Given that molecular volume, a somewhat vague concept, is rather effective, it leads one to wonder: can the existing PubChem 3-D neighboring relationship, which consists of billions of shape similar conformer pairs from tens of millions of unique small molecules, be used to identify additional shape descriptor relationships? Or, put more specifically, can one place an upper bound on shape similarity using other "fuzzy" shape-like concepts like length, width, and height? Results Using a basis set of 4.18 billion 3-D neighbor pairs identified from single conformer per compound neighboring of 17.1 million molecules, shape descriptors were computed for all conformers. These steric shape descriptors included several forms of molecular volume and shape quadrupoles, which essentially embody the length, width, and height of a conformer. For a given 3-D neighbor conformer pair, the volume and each quadrupole component (Qx, Qy, and Qz) were binned and their frequency of occurrence was examined. Per molecular volume type, this effectively produced three different maps, one per quadrupole component (Qx, Qy, and Qz), of allowed values for the similarity metric, shape Tanimoto (ST) ≥ 0.8. The efficiency of these relationships (in terms of true positive, true negative, false positive and false negative) as a function of ST threshold was determined in a test run of 13.2 billion conformer pairs not previously considered by the 3-D neighbor set

  19. Modelling the urban air quality in Hamburg with the new city-scale chemistry transport model CityChem

    NASA Astrophysics Data System (ADS)

    Karl, Matthias; Ramacher, Martin; Aulinger, Armin; Matthias, Volker; Quante, Markus

    2017-04-01

    Air quality modelling plays an important role by providing guidelines for efficient air pollution abatement measures. Currently, most urban dispersion models treat air pollutants as passive tracer substances or use highly simplified chemistry when simulating air pollutant concentrations on the city-scale. The newly developed urban chemistry-transport model CityChem has the capability of modelling the photochemical transformation of multiple pollutants along with atmospheric diffusion to produce pollutant concentration fields for the entire city on a horizontal resolution of 100 m or even finer and a vertical resolution of 24 layers up to 4000 m height. CityChem is based on the Eulerian urban dispersion model EPISODE of the Norwegian Institute for Air Research (NILU). CityChem treats the complex photochemistry in cities using detailed EMEP chemistry on an Eulerian 3-D grid, while using simple photo-stationary equilibrium on a much higher resolution grid (receptor grid), i.e. close to industrial point sources and traffic sources. The CityChem model takes into account that long-range transport contributes to urban pollutant concentrations. This is done by using 3-D boundary concentrations for the city domain derived from chemistry-transport simulations with the regional air quality model CMAQ. For the study of the air quality in Hamburg, CityChem was set-up with a main grid of 30×30 grid cells of 1×1 km2 each and a receptor grid of 300×300 grid cells of 100×100 m2. The CityChem model was driven with meteorological data generated by the prognostic meteorology component of the Australian chemistry-transport model TAPM. Bottom-up inventories of emissions from traffic, industry, households were based on data of the municipality of Hamburg. Shipping emissions for the port of Hamburg were taken from the Clean North Sea Shipping project. Episodes with elevated ozone (O3) were of specific interest for this study, as these are associated with exceedances of the World

  20. Guide for Teaching Chemistry-Physics Combined 1-2, 3-4 (PSSC - CHEMS).

    ERIC Educational Resources Information Center

    Millstone, H. George

    This guide is written for a combined physics-chemistry course taught over a two-year period. The subject matter contains the major ideas in Chemical Education Materials Study (CHEMS) Chemistry and Physical Science Study Committee (PSSC) Physics. The guide includes discussion of text references, laboratory experiments, films, testing and evaluation…

  1. Retrieval of water vapor column abundance and aerosol properties from ChemCam passive sky spectroscopy

    DOE PAGES

    McConnochie, Timothy H.; Smith, Michael D.; Wolff, Michael J.; ...

    2017-11-03

    In this work, we derive water vapor column abundances and aerosol properties from Mars Science Laboratory (MSL) ChemCam passive mode observations of scattered sky light. This paper covers the methodology and initial results for water vapor and also provides preliminary results for aerosols. The data set presented here includes the results of 113 observations spanning from Mars Year 31 L s = 291° (March 30, 2013) to Mars Year 33 L s= 127° (March 24, 2016). Each ChemCam passive sky observation acquires spectra at two different elevation angles. We fit these spectra with a discrete-ordinates multiple scattering radiative transfer model,more » using the correlated-k approximation for gas absorption bands. The retrieval proceeds by first fitting the continuum of the ratio of the two elevation angles to solve for aerosol properties, and then fitting the continuum-removed ratio to solve for gas abundances. The final step of the retrieval makes use of the observed CO 2 absorptions and the known CO 2 abundance to correct the retrieved water vapor abundance for the effects of the vertical distribution of scattering aerosols and to derive an aerosol scale height parameter. Our water vapor results give water vapor column abundance with a precision of ±0.6 precipitable microns and systematic errors no larger than ±0.3 precipitable microns, assuming uniform vertical mixing. The ChemCam-retrieved water abundances show, with only a few exceptions, the same seasonal behavior and the same timing of seasonal minima and maxima as the TES, CRISM, and REMS-H data sets that we compare them to. However ChemCam-retrieved water abundances are generally lower than zonal and regional scale from-orbit water vapor data, while at the same time being significantly larger than pre-dawn REMS-H abundances. Pending further analysis of REMS-H volume mixing ratio uncertainties, the differences between ChemCam and REMS-H pre-dawn mixing ratios appear to be much too large to be explained by large

  2. Retrieval of water vapor column abundance and aerosol properties from ChemCam passive sky spectroscopy

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    McConnochie, Timothy H.; Smith, Michael D.; Wolff, Michael J.

    In this work, we derive water vapor column abundances and aerosol properties from Mars Science Laboratory (MSL) ChemCam passive mode observations of scattered sky light. This paper covers the methodology and initial results for water vapor and also provides preliminary results for aerosols. The data set presented here includes the results of 113 observations spanning from Mars Year 31 L s = 291° (March 30, 2013) to Mars Year 33 L s= 127° (March 24, 2016). Each ChemCam passive sky observation acquires spectra at two different elevation angles. We fit these spectra with a discrete-ordinates multiple scattering radiative transfer model,more » using the correlated-k approximation for gas absorption bands. The retrieval proceeds by first fitting the continuum of the ratio of the two elevation angles to solve for aerosol properties, and then fitting the continuum-removed ratio to solve for gas abundances. The final step of the retrieval makes use of the observed CO 2 absorptions and the known CO 2 abundance to correct the retrieved water vapor abundance for the effects of the vertical distribution of scattering aerosols and to derive an aerosol scale height parameter. Our water vapor results give water vapor column abundance with a precision of ±0.6 precipitable microns and systematic errors no larger than ±0.3 precipitable microns, assuming uniform vertical mixing. The ChemCam-retrieved water abundances show, with only a few exceptions, the same seasonal behavior and the same timing of seasonal minima and maxima as the TES, CRISM, and REMS-H data sets that we compare them to. However ChemCam-retrieved water abundances are generally lower than zonal and regional scale from-orbit water vapor data, while at the same time being significantly larger than pre-dawn REMS-H abundances. Pending further analysis of REMS-H volume mixing ratio uncertainties, the differences between ChemCam and REMS-H pre-dawn mixing ratios appear to be much too large to be explained by large

  3. Calibration of the MSL/ChemCam/LIBS Remote Sensing Composition Instrument

    NASA Technical Reports Server (NTRS)

    Wiens, R. C.; Maurice S.; Bender, S.; Barraclough, B. L.; Cousin, A.; Forni, O.; Ollila, A.; Newsom, H.; Vaniman, D.; Clegg, S.; hide

    2011-01-01

    The ChemCam instrument suite on board the 2011 Mars Science Laboratory (MSL) Rover, Curiosity, will provide remote-sensing composition information for rock and soil samples within seven meters of the rover using a laser-induced breakdown spectroscopy (LIBS) system, and will provide context imaging with a resolution of 0.10 mradians using the remote micro-imager (RMI) camera. The high resolution is needed to image the small analysis footprint of the LIBS system, at 0.2-0.6 mm diameter. This fine scale analytical capability will enable remote probing of stratigraphic layers or other small features the size of "blueberries" or smaller. ChemCam is intended for rapid survey analyses within 7 m of the rover, with each measurement taking less than 6 minutes. Repeated laser pulses remove dust coatings and provide depth profiles through weathering layers, allowing detailed investigation of rock varnish features as well as analysis of the underlying pristine rock composition. The LIBS technique uses brief laser pulses greater than 10 MW/square mm to ablate and electrically excite material from the sample of interest. The plasma emits photons with wavelengths characteristic of the elements present in the material, permitting detection and quantification of nearly all elements, including the light elements H, Li, Be, B, C, N, O. ChemCam LIBS projects 14 mJ of 1067 nm photons on target and covers a spectral range of 240-850 nm with resolutions between 0.15 and 0.60 nm FWHM. The Nd:KGW laser is passively cooled and is tuned to provide maximum power output from -10 to 0 C, though it can operate at 20% degraded energy output at room temperature. Preliminary calibrations were carried out on the flight model (FM) in 2008. However, the detectors were replaced in 2009, and final calibrations occurred in April-June, 2010. This presentation describes the LIBS calibration and characterization procedures and results, and details plans for final analyses during rover system thermal testing

  4. Modeling of the chemical composition of fine particulate matter: Development and performance assessment of EASYWRF-Chem

    NASA Astrophysics Data System (ADS)

    Mendez, M.; Lebègue, P.; Visez, N.; Fèvre-Nollet, V.; Crenn, V.; Riffault, V.; Petitprez, D.

    2016-03-01

    The European emission Adaptation SYstem for the WRF-Chem model (EASYWRF-Chem) has been developed to generate chemical information supporting the WRF-Chem requirements from any emission inventory based on the CORINAIR methodology. Using RADM2 and RACM2 mechanisms, "emission species" are converted into "model species" thanks to the SAPRC methodology for gas phase pollutant and the PM10 and PM2.5 fractions. Furthermore, by adapting US EPA PM2.5 profiles, the processing of aerosol chemical speciation profiles separates the unspeciated PM2.5 emission into five chemical families: sulfates, nitrates, elemental carbon, organic aerosol and unspeciated aerosol. The evaluation of the model has been performed by separately comparing model outcomes with (i) meteorological measurements; (ii) NO2, O3, PM10 and PM2.5 mass concentrations from the regional air quality monitoring network; (iii) hourly-resolved data from four field campaign measurements, in winter and in summer, on two sites in the French northern region. In the latter, a High Resolution - Time of Flight - Aerosol Mass Spectrometer (HR-ToF-AMS) provided non-refractory PM1 concentrations of sulfate, nitrate and ammonium ions as well as organic matter (OM), while an aethalometer provided black carbon (BC) concentrations in the PM2.5 fraction. Meteorological data (temperature, wind, relative humidity) are well simulated for all the time series data except for specific events as wind direction changes or rainfall. For particulate matter, results are presented by considering firstly the total mass concentration of PM2.5 and PM10. EASYWRF-Chem simulations overestimated the PM10 mass concentrations by + 22% and + 4% for summer and winter periods respectively, whereas for the finer PM2.5 fraction, mass concentrations were overestimated by + 20% in summer and underestimated by - 13% in winter. Simulated sulfate concentrations were underestimated and nitrate concentrations were overestimated but hourly variations were well

  5. Nanoplatforms for Detection, Remediation and Protection Against Chem-Bio Warfare

    NASA Astrophysics Data System (ADS)

    Denkbaş, E. B.; Bayram, C.; Kavaz, D.; Çirak, T.; Demirbilek, M.

    Chemical and biological substances have been used as warfare agents by terrorists by varying degree of sophistication. It is critical that these agents be detected in real-time with high level of sensitively, specificity, and accuracy. Many different types of techniques and systems have been developed to detect these agents. But there are some limitations in these conventional techniques and systems. Limitations include the collection, handling and sampling procedures, detection limits, sample transfer, expensive equipment, personnel training, and detection materials. Due to the unique properties such as quantum effect, very high surface/volume ratio, enhanced surface reactivity, conductivity, electrical and magnetic properties of the nanomaterials offer great opportunity to develop very fast, sensitive, accurate and cost effective detection techniques and systems to detect chemical and biological (chem.-bio) warfare agents. Furthermore, surface modification of the materials is very easy and effective way to get functional or smart surfaces to be used as nano-biosensor platform. In that respect many different types of nanomaterials have been developed and used for the detection, remediation and protection, such as gold and silver nanoparticles, quantum dots, Nano chips and arrays, fluorescent polymeric and magnetic nanoparticles, fiber optic and cantilever based nanobiosensors, nanofibrillar nanostructures etc. This study summarizes preparation and characterization of nanotechnology based approaches for the detection of and remediation and protection against chem.-bio warfare agents.

  6. The ChemViz Project: Using a Supercomputer To Illustrate Abstract Concepts in Chemistry.

    ERIC Educational Resources Information Center

    Beckwith, E. Kenneth; Nelson, Christopher

    1998-01-01

    Describes the Chemistry Visualization (ChemViz) Project, a Web venture maintained by the University of Illinois National Center for Supercomputing Applications (NCSA) that enables high school students to use computational chemistry as a technique for understanding abstract concepts. Discusses the evolution of computational chemistry and provides a…

  7. Decadal application of WRF/Chem for regional air quality and climate modeling over the U.S. under the representative concentration pathways scenarios. Part 1: Model evaluation and impact of downscaling

    NASA Astrophysics Data System (ADS)

    Yahya, Khairunnisa; Wang, Kai; Campbell, Patrick; Chen, Ying; Glotfelty, Timothy; He, Jian; Pirhalla, Michael; Zhang, Yang

    2017-03-01

    An advanced online-coupled meteorology-chemistry model, i.e., the Weather Research and Forecasting Model with Chemistry (WRF/Chem), is applied for current (2001-2010) and future (2046-2055) decades under the representative concentration pathways (RCP) 4.5 and 8.5 scenarios to examine changes in future climate, air quality, and their interactions. In this Part I paper, a comprehensive model evaluation is carried out for current decade to assess the performance of WRF/Chem and WRF under both scenarios and the benefits of downscaling the North Carolina State University's (NCSU) version of the Community Earth System Model (CESM_NCSU) using WRF/Chem. The evaluation of WRF/Chem shows an overall good performance for most meteorological and chemical variables on a decadal scale. Temperature at 2-m is overpredicted by WRF (by ∼0.2-0.3 °C) but underpredicted by WRF/Chem (by ∼0.3-0.4 °C), due to higher radiation from WRF. Both WRF and WRF/Chem show large overpredictions for precipitation, indicating limitations in their microphysics or convective parameterizations. WRF/Chem with prognostic chemical concentrations, however, performs much better than WRF with prescribed chemical concentrations for radiation variables, illustrating the benefit of predicting gases and aerosols and representing their feedbacks into meteorology in WRF/Chem. WRF/Chem performs much better than CESM_NCSU for most surface meteorological variables and O3 hourly mixing ratios. In addition, WRF/Chem better captures observed temporal and spatial variations than CESM_NCSU. CESM_NCSU performance for radiation variables is comparable to or better than WRF/Chem performance because of the model tuning in CESM_NCSU that is routinely made in global models.

  8. Acute toxicity and hazard assessment of Rodeo®, X-77 Spreader®, and Chem-Trol® to aquatic invertebrates

    USGS Publications Warehouse

    Henry, C. J.; Higgins, K. F.; Buhl, K.J.

    1994-01-01

    The herbicide Rodeo® provides waterfowl managers with an effective chemical tool for creating open water habitats in wetlands if its use does not adversely affect native invertebrate communities. The survival of caged Chironomus spp. (midge), Hyalella azteca (amphipod),Stagnicola elodes (pond snail), and Nephelopsis obscura (leech) was assessed in prairie pothole wetlands treated by air with a tank mixture of Rodeo®, the surfactant X-77 Spreader®, and the drift retardant Chem-Trol® at a rate recommended for controlling cattails. Laboratory studies were then conducted to determine the acute toxicities of Rodeo®, X-77 Spreader®, and Chem-Trol®, individually and in simulated tank mixtures, to the same invertebrates and to Daphnia magna in reconstituted water representative of these wetlands. There was no difference in the survival of caged invertebrates between treated and reference wetlands after 21 days. Based on nominal concentrations of the formulations, X-77 Spreader® (LC50s=2.0–14.1 mg/L) was about 83–136 times more toxic than Rodeo® (LC50s=218–1216 mg/L) to aquatic invertebrates. Chem-Trol® killed ≤10% of the animals at 10,000 mg/L and ≤50% of the animals at 28,000 mg/L. Daphnia magna were more sensitive than the other species to X-77 Spreader®, Rodeo®, and the simulated Rodeo® tank mixture (RTM). The joint toxic action of the RTM was additive for amphipods and midges, greater than additive for leeches, and was less than additive for daphnids. X-77 Spreader® was the major toxic component in the RTM. Binary mixtures of X-77 Spreader®, Rodeo®, and Chem-Trol® at tank mixture and equitoxic ratios also showed additive toxicity to amphipods. The use of Rodeo® (applied as a tank mixture with X-77 Spreader® and Chem-Trol®) as a management tool in wetlands does not pose an acute hazard to native aquatic invertebrates because the concentrations of Rodeo®, X-77 Spreader®, and Chem-Trol® found to be acutely toxic to these invertebrates were

  9. Meteorological air quality forecasting using the WRF-Chem model during the LMOS2017 field campaign

    NASA Astrophysics Data System (ADS)

    Stanier, C. O.; Abdioskouei, M.; Carmichael, G. R.; Christiansen, M.; Sobhani, N.

    2017-12-01

    The Lake Michigan Ozone Study (LMOS 2017) occurred during May and June 2017 to address the high ozone episodes in coastal communities surrounding Lake Michigan. Aircraft, ship, mobile lab, and ground-based stations were used in this campaign to build an extensive dataset regarding ozone, its precursors, and particulate matter. The University of Iowa produced high-resolution (4x4 km2 horizontal resolution and 53 vertical levels) forecast products using the WRF-Chem modeling system in support of experimental planning during LMOS 2017. The base forecast system used WRF-Chem 3.6.1 and updated National Emission Inventory (NEI-2011v2). In the updated NEI-2011v2, we reduced the NOx emissions by 28% based on EPA's estimated NOx trends from 2011 to 2017. We ran another daily forecast (perturbed forecast) with 50% reduced NOx emission to capture the sensitivity of ozone to NOx emission and account for the impact of weekend emissions on ozone values. Preliminary in-field evaluation of model performance for clouds, on-shore flows, and surface and aircraft sampled ozone and NOx concentrations found that the model successfully captured much of the observed synoptic variability of onshore flows. The model captured the variability of O3 well, but underpredicted peak ozone during high O3 episodes. In post-campaign WRF-Chem simulations, we investigated the sensitivity of the model to the hydrocarbon emission.

  10. ChemCam passive reflectance spectroscopy of surface materials at the Curiosity landing site, Mars

    NASA Astrophysics Data System (ADS)

    Johnson, Jeffrey R.; Bell, J. F.; Bender, S.; Blaney, D.; Cloutis, E.; DeFlores, L.; Ehlmann, B.; Gasnault, O.; Gondet, B.; Kinch, K.; Lemmon, M.; Le Mouélic, S.; Maurice, S.; Rice, M.; Wiens, R. C.

    2015-03-01

    The spectrometers on the Mars Science Laboratory (MSL) ChemCam instrument were used in passive mode to record visible/near-infrared (400-840 nm) radiance from the martian surface. Using the onboard ChemCam calibration targets' housing as a reflectance standard, we developed methods to collect, calibrate, and reduce radiance observations to relative reflectance. Such measurements accurately reproduce the known reflectance spectra of other calibration targets on the rover, and represent the highest spatial resolution (0.65 mrad) and spectral sampling (<1 nm) visible/near-infrared reflectance spectra from a landed platform on Mars. Relative reflectance spectra of surface rocks and soils match those from orbital observations and multispectral data from the MSL Mastcam camera. Preliminary analyses of the band depths, spectral slopes, and reflectance ratios of the more than 2000 spectra taken during the first year of MSL operations demonstrate at least six spectral classes of materials distinguished by variations in ferrous and ferric components. Initial comparisons of ChemCam spectra to laboratory spectra of minerals and Mars analog materials demonstrate similarities with palagonitic soils and indications of orthopyroxene in some dark rocks. Magnesium-rich "raised ridges" tend to exhibit distinct near-infrared slopes. The ferric absorption downturn typically found for martian materials at <600 nm is greatly subdued in brushed rocks and drill tailings, consistent with their more ferrous nature. Calcium-sulfate veins exhibit the highest relative reflectances observed, but are still relatively red owing to the effects of residual dust. Such dust is overall less prominent on rocks sampled within the "blast zone" immediately surrounding the landing site. These samples were likely affected by the landing thrusters, which partially removed the ubiquitous dust coatings. Increased dust coatings on the calibration targets during the first year of the mission were documented by

  11. ChemCam for Mars Science Laboratory rover, undergoing pre-flight testing

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    None

    2011-10-20

    Los Alamos National Laboratory and partners developed a laser instrument, ChemCam, that will ride on the elevated mast of the Mars Science Laboratory rover Curiosity. The system allows Curiosity to "zap" rocks from a distance, reading their chemical composition through spectroscopic analysis. In this video, laboratory shaker-table testing of the instrument ensures that all of its components are solidly attached and resistant to damage from the rigors of launch, travel and landing.

  12. ChemCam for Mars Science Laboratory rover, undergoing pre-flight testing

    ScienceCinema

    None

    2018-06-06

    Los Alamos National Laboratory and partners developed a laser instrument, ChemCam, that will ride on the elevated mast of the Mars Science Laboratory rover Curiosity. The system allows Curiosity to "zap" rocks from a distance, reading their chemical composition through spectroscopic analysis. In this video, laboratory shaker-table testing of the instrument ensures that all of its components are solidly attached and resistant to damage from the rigors of launch, travel and landing.

  13. Impact of improved soil climatology and intialization on WRF-chem dust simulations over West Asia

    NASA Astrophysics Data System (ADS)

    Omid Nabavi, Seyed; Haimberger, Leopold; Samimi, Cyrus

    2016-04-01

    Meteorological forecast models such as WRF-chem are designed to forecast not only standard atmospheric parameters but also aerosol, particularly mineral dust concentrations. It has therefore become an important tool for the prediction of dust storms in West Asia where dust storms have the considerable impact on living conditions. However, verification of forecasts against satellite data indicates only moderate skill in prediction of such events. Earlier studies have already indicated that the erosion factor, land use classification, soil moisture, and temperature initializations play a critical role in the accuracy of WRF-chem dust simulations. In the standard setting the erosion factor and land use classification are based on topographic variations and post-processed images of the advanced very high-resolution radiometer (AVHRR) during the period April 1992-March 1993. Furthermore, WRF-chem is normally initialized by the soil moisture and temperature of Final Analysis (FNL) model on 1.0x1.0 degree grids. In this study, we have changed boundary initial conditions so that they better represent current changing environmental conditions. To do so, land use (only bare soil class) and the erosion factor were both modified using information from MODIS deep blue AOD (Aerosol Optical Depth). In this method, bare soils are where the relative frequency of dust occurrence (deep blue AOD > 0.5) is more than one-third of a given month. Subsequently, the erosion factor, limited within the bare soil class, is determined by the monthly frequency of dust occurrence ranging from 0.3 to 1. It is worth to mention, that 50 percent of calculated erosion factor is afterward assigned to sand class while silt and clay classes each gain 25 percent of it. Soil moisture and temperature from the Global Land Data Assimilation System (GLDAS) were utilized to provide these initializations in higher resolution of 0.25 degree than in the standard setting. Modified and control simulations were

  14. Air quality modeling for the urban Jackson, Mississippi Region using a high resolution WRF/Chem model.

    PubMed

    Yerramilli, Anjaneyulu; Dodla, Venkata B; Desamsetti, Srinivas; Challa, Srinivas V; Young, John H; Patrick, Chuck; Baham, Julius M; Hughes, Robert L; Yerramilli, Sudha; Tuluri, Francis; Hardy, Mark G; Swanier, Shelton J

    2011-06-01

    In this study, an attempt was made to simulate the air quality with reference to ozone over the Jackson (Mississippi) region using an online WRF/Chem (Weather Research and Forecasting-Chemistry) model. The WRF/Chem model has the advantages of the integration of the meteorological and chemistry modules with the same computational grid and same physical parameterizations and includes the feedback between the atmospheric chemistry and physical processes. The model was designed to have three nested domains with the inner-most domain covering the study region with a resolution of 1 km. The model was integrated for 48 hours continuously starting from 0000 UTC of 6 June 2006 and the evolution of surface ozone and other precursor pollutants were analyzed. The model simulated atmospheric flow fields and distributions of NO2 and O3 were evaluated for each of the three different time periods. The GIS based spatial distribution maps for ozone, its precursors NO, NO2, CO and HONO and the back trajectories indicate that all the mobile sources in Jackson, Ridgeland and Madison contributing significantly for their formation. The present study demonstrates the applicability of WRF/Chem model to generate quantitative information at high spatial and temporal resolution for the development of decision support systems for air quality regulatory agencies and health administrators.

  15. Liquid Chromatographic Analysis of the Free Sugars in Sweet Corn: a Method Indicative of Maturity and of Quality Changes Related to Processing Techniques

    DTIC Science & Technology

    1977-07-01

    F. Flora and R. C. Wiley, J . Food Scl., 39, 770 (1974). 2G. Rumpf, J . Mawson and H. Hansen, J . Sci. Food Agric., 23, 193 (1972). L Hough and J . K. N...Clamp, T . Bhatti and R. E. Chambers, Methods Biochem. Anal., 19, 229 (1971). 11 J . M. Richey, H. G. Richey, Jr. and R. Schraer, Analyt. Biochem., 9...C W Culpepper and C, A. Magoon, J . Agr. Res., 28, 403 (1924). -0. M Doty, G. M. Smith, J . R. Roach and J . T . Sullivan, Indiana Agr. Exp. Sta. Bull

  16. Evaluating WRF-Chem aerosol indirect effects in Southeast Pacific marine stratocumulus during VOCALS-REx

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Saide, Pablo; Spak, S. N.; Carmichael, Gregory

    2012-03-30

    We evaluate a regional-scale simulation with the WRF-Chem model for the VAMOS (Variability of the American Monsoon Systems) Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx), which sampled the Southeast Pacific's persistent stratocumulus deck. Evaluation of VOCALS-REx ship-based and aircraft observations focuses on analyzing how aerosol loading affects marine boundary layer (MBL) dynamics and cloud microphysics. We compare local time series and campaign averaged longitudinal gradients, and highlight differences in model simulations with (W) and without wet (NW) deposition processes. The higher aerosol loadings in the NW case produce considerable changes in MBL dynamics and cloud microphysics, in accordance with the established conceptualmore » model of aerosol indirect effects. These include increase in cloud albedo, increase in MBL and cloud heights, drizzle suppression, increase in liquid water content, and increase in cloud lifetime. Moreover, better statistical representation of aerosol mass and number concentration improves model fidelity in reproducing observed spatial and temporal variability in cloud properties, including top and base height, droplet concentration, water content, rain rate, optical depth (COD) and liquid water path (LWP). Together, these help to quantify confidence in WRF-Chem's modeled aerosol-cloud interactions, while identifying structural and parametric uncertainties including: irreversibility in rain wet removal; overestimation of marine DMS and sea salt emissions and accelerated aqueous sulfate conversion. Our findings suggest that WRF-Chem simulates marine cloud-aerosol interactions at a level sufficient for applications in forecasting weather and air quality and studying aerosol climate forcing, including the reliability required for policy analysis and geo-engineering applications.« less

  17. EOS CHEM: A Mission to Study Ozone and Climate

    NASA Technical Reports Server (NTRS)

    Schoeberl, Mark

    1998-01-01

    The Earth's stratosphere contains the ozone layer, which shields us from the Sun@ harmful ultraviolet (UV) radiation. Ozone is destroyed through chemical reactions involving natural and man-made nitrogen, hydrogen, bromine, and chlorine compounds. The release of chlorofluoro-carbons CFCs) has caused a dramatic decrease in the protective stratospheric ozone layer during the last two decades. Detection of stratospheric ozone depletion led to regulation and phase-out of CFC production worldwide. As a result, man-made chlorine levels in the atmosphere are slowly beginning to decrease. CHEM will be able to determine whether the stratospheric ozone layer is now recovering, as predicted by scientific models.

  18. A new WRF-Chem treatment for studying regional-scale impacts of cloud processes on aerosol and trace gases in parameterized cumuli

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Berg, L. K.; Shrivastava, M.; Easter, R. C.

    A new treatment of cloud effects on aerosol and trace gases within parameterized shallow and deep convection, and aerosol effects on cloud droplet number, has been implemented in the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) version 3.2.1 that can be used to better understand the aerosol life cycle over regional to synoptic scales. The modifications to the model include treatment of the cloud droplet number mixing ratio; key cloud microphysical and macrophysical parameters (including the updraft fractional area, updraft and downdraft mass fluxes, and entrainment) averaged over the population of shallow clouds, or a single deep convectivemore » cloud; and vertical transport, activation/resuspension, aqueous chemistry, and wet removal of aerosol and trace gases in warm clouds. These changes have been implemented in both the WRF-Chem chemistry packages as well as the Kain–Fritsch (KF) cumulus parameterization that has been modified to better represent shallow convective clouds. Testing of the modified WRF-Chem has been completed using observations from the Cumulus Humilis Aerosol Processing Study (CHAPS). The simulation results are used to investigate the impact of cloud–aerosol interactions on regional-scale transport of black carbon (BC), organic aerosol (OA), and sulfate aerosol. Based on the simulations presented here, changes in the column-integrated BC can be as large as –50% when cloud–aerosol interactions are considered (due largely to wet removal), or as large as +40% for sulfate under non-precipitating conditions due to sulfate production in the parameterized clouds. The modifications to WRF-Chem are found to account for changes in the cloud droplet number concentration (CDNC) and changes in the chemical composition of cloud droplet residuals in a way that is consistent with observations collected during CHAPS. Efforts are currently underway to port the changes described here to the latest version of WRF-Chem, and it

  19. A new WRF-Chem treatment for studying regional-scale impacts of cloud processes on aerosol and trace gases in parameterized cumuli

    DOE PAGES

    Berg, L. K.; Shrivastava, M.; Easter, R. C.; ...

    2015-02-24

    A new treatment of cloud effects on aerosol and trace gases within parameterized shallow and deep convection, and aerosol effects on cloud droplet number, has been implemented in the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) version 3.2.1 that can be used to better understand the aerosol life cycle over regional to synoptic scales. The modifications to the model include treatment of the cloud droplet number mixing ratio; key cloud microphysical and macrophysical parameters (including the updraft fractional area, updraft and downdraft mass fluxes, and entrainment) averaged over the population of shallow clouds, or a single deep convectivemore » cloud; and vertical transport, activation/resuspension, aqueous chemistry, and wet removal of aerosol and trace gases in warm clouds. These changes have been implemented in both the WRF-Chem chemistry packages as well as the Kain–Fritsch (KF) cumulus parameterization that has been modified to better represent shallow convective clouds. Testing of the modified WRF-Chem has been completed using observations from the Cumulus Humilis Aerosol Processing Study (CHAPS). The simulation results are used to investigate the impact of cloud–aerosol interactions on regional-scale transport of black carbon (BC), organic aerosol (OA), and sulfate aerosol. Based on the simulations presented here, changes in the column-integrated BC can be as large as –50% when cloud–aerosol interactions are considered (due largely to wet removal), or as large as +40% for sulfate under non-precipitating conditions due to sulfate production in the parameterized clouds. The modifications to WRF-Chem are found to account for changes in the cloud droplet number concentration (CDNC) and changes in the chemical composition of cloud droplet residuals in a way that is consistent with observations collected during CHAPS. Efforts are currently underway to port the changes described here to the latest version of WRF-Chem, and it

  20. Inclusion of biomass burning in WRF-Chem: Impact of wildfires on weather forecasts

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Grell, G. A.; Freitas, Saulo; Stuefer, Martin

    2011-06-06

    A plume rise algorithm for wildfires was included in WRF-Chem, and applied to look at the impact of intense wildfires during the 2004 Alaska wildfire season on weather forecasts using model resolutions of 10km and 2km. Biomass burning emissions were estimated using a biomass burning emissions model. In addition, a 1-D, time-dependent cloud model was used online in WRF-Chem to estimate injection heights as well as the final emission rates. It was shown that with the inclusion of the intense wildfires of the 2004 fire season in the model simulations, the interaction of the aerosols with the atmospheric radiation ledmore » to significant modifications of vertical profiles of temperature and moisture in cloud-free areas. On the other hand, when clouds were present, the high concentrations of fine aerosol (PM2.5) and the resulting large numbers of Cloud Condensation Nuclei (CCN) had a strong impact on clouds and microphysics, with decreased precipitation coverage and precipitation amounts during the first 12 hours of the integration, but significantly stronger storms during the afternoon hours.« less

  1. iNR-PhysChem: A Sequence-Based Predictor for Identifying Nuclear Receptors and Their Subfamilies via Physical-Chemical Property Matrix

    PubMed Central

    Xiao, Xuan; Wang, Pu; Chou, Kuo-Chen

    2012-01-01

    Nuclear receptors (NRs) form a family of ligand-activated transcription factors that regulate a wide variety of biological processes, such as homeostasis, reproduction, development, and metabolism. Human genome contains 48 genes encoding NRs. These receptors have become one of the most important targets for therapeutic drug development. According to their different action mechanisms or functions, NRs have been classified into seven subfamilies. With the avalanche of protein sequences generated in the postgenomic age, we are facing the following challenging problems. Given an uncharacterized protein sequence, how can we identify whether it is a nuclear receptor? If it is, what subfamily it belongs to? To address these problems, we developed a predictor called iNR-PhysChem in which the protein samples were expressed by a novel mode of pseudo amino acid composition (PseAAC) whose components were derived from a physical-chemical matrix via a series of auto-covariance and cross-covariance transformations. It was observed that the overall success rate achieved by iNR-PhysChem was over 98% in identifying NRs or non-NRs, and over 92% in identifying NRs among the following seven subfamilies: NR1thyroid hormone like, NR2HNF4-like, NR3estrogen like, NR4nerve growth factor IB-like, NR5fushi tarazu-F1 like, NR6germ cell nuclear factor like, and NR0knirps like. These rates were derived by the jackknife tests on a stringent benchmark dataset in which none of protein sequences included has pairwise sequence identity to any other in a same subset. As a user-friendly web-server, iNR-PhysChem is freely accessible to the public at either http://www.jci-bioinfo.cn/iNR-PhysChem or http://icpr.jci.edu.cn/bioinfo/iNR-PhysChem. Also a step-by-step guide is provided on how to use the web-server to get the desired results without the need to follow the complicated mathematics involved in developing the predictor. It is anticipated that iNR-PhysChem may become a useful high throughput tool

  2. ConfChem Conference on Flipped Classroom: Using a Blog to Flip a Classroom

    ERIC Educational Resources Information Center

    Haile, January D.

    2015-01-01

    This communication summarizes one of the invited papers to the Flipped Classroom ACS Division of Chemical Education Committee on Computers in Chemical Education online ConfChem held from May 18 to June 24, 2014. Just in Time Teaching is a technique in which students read the material before class and respond to a few questions. In a first-year…

  3. Air Quality Modeling for the Urban Jackson, Mississippi Region Using a High Resolution WRF/Chem Model

    PubMed Central

    Yerramilli, Anjaneyulu; Dodla, Venkata B.; Desamsetti, Srinivas; Challa, Srinivas V.; Young, John H.; Patrick, Chuck; Baham, Julius M.; Hughes, Robert L.; Yerramilli, Sudha; Tuluri, Francis; Hardy, Mark G.; Swanier, Shelton J.

    2011-01-01

    In this study, an attempt was made to simulate the air quality with reference to ozone over the Jackson (Mississippi) region using an online WRF/Chem (Weather Research and Forecasting–Chemistry) model. The WRF/Chem model has the advantages of the integration of the meteorological and chemistry modules with the same computational grid and same physical parameterizations and includes the feedback between the atmospheric chemistry and physical processes. The model was designed to have three nested domains with the inner-most domain covering the study region with a resolution of 1 km. The model was integrated for 48 hours continuously starting from 0000 UTC of 6 June 2006 and the evolution of surface ozone and other precursor pollutants were analyzed. The model simulated atmospheric flow fields and distributions of NO2 and O3 were evaluated for each of the three different time periods. The GIS based spatial distribution maps for ozone, its precursors NO, NO2, CO and HONO and the back trajectories indicate that all the mobile sources in Jackson, Ridgeland and Madison contributing significantly for their formation. The present study demonstrates the applicability of WRF/Chem model to generate quantitative information at high spatial and temporal resolution for the development of decision support systems for air quality regulatory agencies and health administrators. PMID:21776240

  4. HIV Structural Database using Chem BLAST for all classes of AIDS inhibitors

    National Institute of Standards and Technology Data Gateway

    SRD 155 HIV Structural Database using Chem BLAST for all classes of AIDS inhibitors (Web, free access)   The HIV structural database (HIVSDB) is a comprehensive collection of the structures of HIV protease, both of unliganded enzyme and of its inhibitor complexes. It contains abstracts and crystallographic data such as inhibitor and protein coordinates for 248 data sets, of which only 141 are from the Protein Data Bank (PDB).

  5. Evaluating WRF-Chem aerosol indirect effects in Southeast Pacific marine stratocumulus during VOCALS-REx

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Saide P. E.; Springston S.; Spak, S. N.

    2012-03-29

    We evaluate a regional-scale simulation with the WRF-Chem model for the VAMOS (Variability of the American Monsoon Systems) Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx), which sampled the Southeast Pacific's persistent stratocumulus deck. Evaluation of VOCALS-REx ship-based and three aircraft observations focuses on analyzing how aerosol loading affects marine boundary layer (MBL) dynamics and cloud microphysics. We compare local time series and campaign-averaged longitudinal gradients, and highlight differences in model simulations with (W) and without (NW) wet deposition processes. The higher aerosol loadings in the NW case produce considerable changes in MBL dynamics and cloud microphysics, in accordance with the established conceptualmore » model of aerosol indirect effects. These include increase in cloud albedo, increase in MBL and cloud heights, drizzle suppression, increase in liquid water content, and increase in cloud lifetime. Moreover, better statistical representation of aerosol mass and number concentration improves model fidelity in reproducing observed spatial and temporal variability in cloud properties, including top and base height, droplet concentration, water content, rain rate, optical depth (COD) and liquid water path (LWP). Together, these help to quantify confidence in WRF-Chem's modeled aerosol-cloud interactions, especially in the activation parameterization, while identifying structural and parametric uncertainties including: irreversibility in rain wet removal; overestimation of marine DMS and sea salt emissions, and accelerated aqueous sulfate conversion. Our findings suggest that WRF-Chem simulates marine cloud-aerosol interactions at a level sufficient for applications in forecasting weather and air quality and studying aerosol climate forcing, and may do so with the reliability required for policy analysis.« less

  6. ChemCam at Gale Crater: Highlights and Discoveries from Three Years of Chemical Measurements on Mars

    NASA Astrophysics Data System (ADS)

    Blaney, Diana L.; Wiens, Roger; Maurice, Sylvestre; Gasnault, Olivier; Anderson, Ryan; Bridges, John; Bridges, Nathan; Clegg, Samuel; Clark, Benton; Ehlmann, Bethany; Dyar, Melinda D.; Fisk, Martin; Francis, Raymond; Fabre, Cecile; Forni, Olivier; Frydenvang, Jens; Johnson, Jeffery; Lanza, Nina; Leveille, Richard; Lasue, Jeremie; Le Deit, Laetitia; Mangold, Nicholas; Melikechi, Noureddine; Nachon, Marion; Newsom, Horton; Payre, Valerie; Rapin, William; Sautter, Violane; Vaniman, David; Grotzinger, John; Vasavad, Ashwin; Crisp, Joy

    2015-11-01

    ChemCam has undertaken a detailed chemical investigation of the rocks and soils at Gale crater over the last three years with over six thousand separate geochemical measurements. Recent recalibration of the ChemCam data using a new library of >350 geochemical standards has enabled increased elemental accuracies over a wider compositional range. The increased accuracy combined with ChemCam’s small spot size allows for the chemistry of mineral end members including feldspars, high silica, oxide rich grains to be identified. ChemCam has observed both sedimentary and igneous compositions. Igneous compositions are generally present in conglomerates and in float rocks. Compositions show a wide range of igneous chemistry ranging from basaltic to feldspar rich assemblages.Sedimentary rocks have a wide range of compositions reflecting both differences in chemical source regions and in depositional and diagenetic histories. The “Sheepbed” mudstones cluster around Martian average crustal compositions. The “Kimberley” outcrop showed enhanced potassium reaching concentrations up to ~6 wt% K2O. More recent observations in the Murray Formation at the base of Mt. Sharp reveal mudstones that are lower in magnesium and higher in silica and aluminum than the more basaltic mudstones previously investigated. Extremely high silica (75-85 wt%) deposits have also been identified. The high silica observations were associated with increased TiO2, While the Murray mudstones are generally low in magnesium, local enhancements in magnesium have also been noted associated with resistant facies in the outcrop. Chemical trends also indicate that iron oxide phases may also be present as cements. Sandstone facies with a mafic composition are also present. Veins in the unit also show a wide range of compositions indicating fluid chemistries rich in calcium sulfate, fluorine, magnesium and iron were present. Vein chemistry could be the result of distinct fluids migrating through from a

  7. Worldwide biogenic soil NOx emission estimates from OMI NO2 observations and the GEOS-Chem model

    NASA Astrophysics Data System (ADS)

    Vinken, Geert; Boersma, Folkert; Maasakkers, Bram; Martin, Randall

    2014-05-01

    Bacteria in soils are an important source of biogenic nitrogen oxides (NOx = NO + NO2), which are important precursors for ozone (O3) formation. Furthermore NOx emissions contribute to increased nitrogen deposition and particulate matter formation. Bottom-up estimates of global soil NOx emissions range from 4 to 27 Tg N / yr, reflecting our incomplete knowledge of emission factors and processes driving these emissions. In this study we used, for the first time, OMI NO2 columns on all continents to reduce the uncertainty in soil NOx emissions. Regions and months dominated by soil NOx emissions were identified using a filtering scheme in the GEOS-Chem chemistry transport model. Consequently, we compared OMI observed NO2 observed columns to GEOS-Chem simulated columns and provide constraints for these months in 11 regions. This allows us to provide a top-down emission inventory for 2005 for soil NOx emissions from all continents. Our total global soil NOx emission inventory amounts to 10 Tg N / yr. Our estimate is 4% higher than the GEOS-Chem a priori (Hudman et al., 2012), but substantial regional differences exist (e.g. +20% for Sahel and India; and -40% for mid-USA). We furthermore observed a stronger seasonal cycle in the Sahel region, indicating directions for possible future improvements to the parameterization currently used in GEOS-Chem. We validated NO2 concentrations simulated with this new top-down inventory against surface NO2 measurements from monitoring stations in Africa, the USA and Europe. On the whole, we conclude that simulations with our new top-down inventory better agree with measurements. Our work shows that satellite retrieved NO2 columns can improve estimates of soil NOx emissions over sparsely monitored remote rural areas. We show that the range in previous estimates of soil NOx emissions is too large, and global emissions are most likely around 10 Tg N/yr, in agreement with the most recent parameterizations.

  8. Calibration of the Fluorine, Chlorine and Hydrogen Content of Apatites With the ChemCam LIBS Instrument

    NASA Technical Reports Server (NTRS)

    Meslin, P.-Y.; Cicutto, L.; Forni, O.; Drouet, C.; Rapin, W.; Nachon, M.; Cousin, A.; Blank, J. G.; McCubbin, F. M.; Gasnault, O.; hide

    2016-01-01

    Determining the composition of apatites is important to understand the behavior of volatiles during planetary differentiation. Apatite is an ubiquitous magmatic mineral in the SNC meteorites. It is a significant reservoir of halogens in these meteorites and has been used to estimate the halogen budget of Mars. Apatites have been identified in sandstones and pebbles at Gale crater by ChemCam, a Laser-Induced Breakdown Spectroscometer (LIBS) instrument onboard the Curiosity rover. Their presence was inferred from correlations between calcium, fluorine (using the CaF molecular band centered near 603 nm, whose detection limit is much lower that atomic or ionic lines and, in some cases, phosphorus (whose detection limit is much larger). An initial quantification of fluorine, based on fluorite (CaF2)/basalt mixtures and obtained at the LANL laboratory, indicated that the excess of F/Ca (compared to the stoichiometry of pure fluorapatites) found on Mars in some cases could be explained by the presence of fluorite. Chlorine was not detected in these targets, at least above a detection limit of 0.6 wt% estimated from. Fluorapatite was later also detected by X-ray diffraction (with CheMin) at a level of approx.1wt% in the Windjana drill sample (Kimberley area), and several points analyzed by ChemCam in this area also revealed a correlation between Ca and F. The in situ detection of F-rich, Cl-poor apatites contrasts with the Cl-rich, F-poor compositions of apatites found in basaltic shergottites and in gabbroic clasts from the martian meteorite NWA 7034, which were also found to be more Cl-rich than apatites from basalts on Earth, the Moon, or Vesta. The in situ observations could call into question one of the few possible explanations brought forward to explain the SNC results, namely that Mars may be highly depleted in fluorine. The purpose of the present study is to refine the calibration of the F, Cl, OH and P signals measured by the ChemCam LIBS instrument, initiated

  9. In silico genotoxicity of coumarins: application of the Phenol-Explorer food database to functional food science.

    PubMed

    Guardado Yordi, E; Matos, M J; Pérez Martínez, A; Tornes, A C; Santana, L; Molina, E; Uriarte, E

    2017-08-01

    Coumarins are a group of phytochemicals that may be beneficial or harmful to health depending on their type and dosage and the matrix that contains them. Some of these compounds have been proven to display pro-oxidant and clastogenic activities. Therefore, in the current work, we have studied the coumarins that are present in food sources extracted from the Phenol-Explorer database in order to predict their clastogenic activity and identify the structure-activity relationships and genotoxic structural alerts using alternative methods in the field of computational toxicology. It was necessary to compile information on the type and amount of coumarins in different food sources through the analysis of databases of food composition available online. A virtual screening using a clastogenic model and different software, such as MODESLAB, ChemDraw and STATISTIC, was performed. As a result, a table of food composition was prepared and qualitative information from this data was extracted. The virtual screening showed that the esterified substituents inactivate molecules, while the methoxyl and hydroxyl substituents contribute to their activity and constitute, together with the basic structures of the studied subclasses, clastogenic structural alerts. Chemical subclasses of simple coumarins and furocoumarins were classified as active (xanthotoxin, isopimpinellin, esculin, scopoletin, scopolin and bergapten). In silico genotoxicity was mainly predicted for coumarins found in beer, sherry, dried parsley, fresh parsley and raw celery stalks. The results obtained can be interesting for the future design of functional foods and dietary supplements. These studies constitute a reference for the genotoxic chemoinformatic analysis of bioactive compounds present in databases of food composition.

  10. The Chem-E-Car as a Vehicle for Service Learning through K-12 Outreach

    ERIC Educational Resources Information Center

    Chirdon, William

    2017-01-01

    This article presents the results of combining the American Institute of Chemical Engineers' (AIChE) Chem-E-Car competition activities with engineering outreach to K-12 students in a service-learning course. Survey results are presented to show how the program develops technical skills as well as leadership, teamwork, and communication skills in…

  11. Charactering biomass burning aerosol in the Weather Research and Forecasting model with Chemistry (WRF-Chem), with evaluation against SAMBBA flight data.

    NASA Astrophysics Data System (ADS)

    Archer-Nicholls, S.; Lowe, D.; Darbyshire, E.; Morgan, W.; Freitas, S. R.; Longo, K.; Coe, H.; McFiggans, G.

    2014-12-01

    The burning of forests in the Amazonia region is a globally significant source of carbonaceous aerosol, containing both absorbing and scattering components. Biomass burning aerosol (BBA) are efficient CCN, modifying cloud properties and influencing atmospheric circulation and precipitation tendencies. The impacts of BBA are highly dependent on their size distribution and composition. Studies in this region can therefore benefit greatly from the use of state-of-the-art sectional aerosol representations. A bottom-up fire emissions inventory, 3BEM, has been developed by Longo et al.1. It uses satellite products to identify fire locations, applying the emissions factors of Andrei and Merlot3 to generate daily emission maps. Flaming emissions are very buoyant, and a method for injecting emissions at altitude is needed to accurately describe the vertical profile of BBA. A parameterisation has been developed to simulate this sub-grid process4, and previously implemented in WRF-Chem using a modal aerosol scheme5. For this work we have modified the WRF-Chem model to simulate 3BEM emissions using the MOSAIC sectional aerosol scheme6. This modified version of WRF-Chem v3.4.1 has been run for September 2012 over South America (25km grid-spacing). We will present model results evaluating the modelled aerosol vertical distribution, size distribution, composition and optical properties against measurements taken by the FAAM BAe-146 research aircraft during the SAMBBA field campaign. The plume-rise parameterisation was found to inject flaming emissions too high over most fires, resulting in high modelled aerosol loadings at high altitude. We probed the behaviour of the parameterisation by developing a new SAMBBA-tuned 3BEM emissions scenario, which uses more realistic estimates of fire size. Results from high-resolution (5 and 1km) nested simulations will also be presented, in order to evaluate the impacts of explicit aerosol-cloud interactions in non-parameterised clouds. 1. K

  12. The Impact of Chemical Mechanism Design on Simulated Surface Ozone in CAM-Chem

    NASA Astrophysics Data System (ADS)

    Schwantes, R.; Emmons, L. K.; Orlando, J. J.; Tyndall, G. S.

    2017-12-01

    Many regions in the United States have poor air quality because of high levels of ozone. Global and regional chemical transport models are important tools for recommending regulatory policy directions to efficiently reduce ozone. Ozone is intrinsically hard to simulate in global and regional models because the amount of ozone present is controlled by large non-linear sources and sinks. Recent field campaigns have concluded that monoterpene chemistry is particularly important for the NOx budget and thereby O3 formation. However, many regional and global models have none or heavily reduced monoterpene chemical schemes. In this study, the chemical mechanism for isoprene and monoterpene oxidation will be significantly improved and updated in CAM-Chem (Community Atmosphere Model with chemistry), which is a component of the Community Earth System Model (CESM). In particular, the updates will focus on accurately portraying organic nitrate formation and fate. The impact of various uncertainties (e.g., nitrate yields, later generation chemistry, loss of organic nitrates to aerosols via hydrolysis, etc.) on ozone formation will be tested. This study will both improve the chemistry in CAM-Chem and reveal lingering uncertainties that have the largest impact on ozone formation.

  13. Effects on Student Achievement in General Chemistry following Participation in an Online Preparatory Course: ChemPrep, a Voluntary, Self-Paced, Online Introduction to Chemistry

    ERIC Educational Resources Information Center

    Botch, Beatrice; Day, Roberta; Vining, William; Stewart, Barbara; Rath, Kenneth; Peterfreund, Alan; Hart, David

    2007-01-01

    ChemPrep was developed to be a stand-alone preparatory short-course to help students succeed in general chemistry. It is Web-based and delivered using the OWL system. Students reported that the ChemPrep materials (short information pages, parameterized questions with detailed feedback, tutorials, and answers to questions through the OWL message…

  14. Response to ``Comment on `Slow Debye-type peak observed in the dielectric response of polyalcohols' '' [J. Chem. Phys. 134, 037101 (2011)

    NASA Astrophysics Data System (ADS)

    Bergman, R.; Jansson, H.; Swenson, J.

    2011-01-01

    In our recent article [R. Bergman et al., J. Chem. Phys. 132, 044504 (2010)] we investigated some polyalcohols, i.e., glycerol, xylitol, and sorbitol by dielectric spectroscopy. In the study, a low-frequency peak of Debye character that normally is hidden by the large low-frequency dispersion due to conductivity was revealed by analyzing the real part of the permittivity and by using a thin Teflon film to suppress the low-frequency dispersion. We agree with the comment by Paluch et al. [J. Chem. Phys. 134, 037101 (2011)] that the Teflon film setup will indeed create a peak due to the dc conductivity. However, due to the fact that the location of the peak was almost identical in measurement with and without Teflon, we unfortunately mainly showed the data measured with Teflon, despite that it could also be observed in the real part of the permittivity without using the Teflon setup, as shown in our original article [R. Bergman et al., J. Chem. Phys. 132, 044504 (2010)]. Here, we show that the low-frequency peak of Debye character can also be observed by subtracting the dc conductivity. Furthermore, we show that the modulus representation used in Paluch et al. [J. Chem. Phys. 134, 037101 (2011).] is also not suitable for detecting processes hidden by the conductivity.

  15. ChemTechLinks: Alliances for Chemical Technician Education

    NASA Astrophysics Data System (ADS)

    Nameroff, Tamara

    2003-09-01

    ChemTechLinks (CTL) is a project of the American Chemical Society (ACS) Educational and International Activities Division and funded by the National Science Foundation to support and advance chemistry-based technician education. The project aims to help improve technician education programs, foster academic-industry alliances, provide professional development opportunities for faculty, and increase student recruitment into chemical technology. The CTL Web site serves as an information clearinghouse and link to other ACS resources and programs, including a Web-based, Voluntary Industry Standards (VIS) database, the Chemistry Technician Program Approval Service, the College Chemistry Consultants Service, summer workshops for high school teachers and two-year college faculty that emphasize a technology-oriented curriculum, scholarships for two-year college faculty to attend ACS Short Courses, a self-study instructional guide for faculty to use in preparing for classroom instruction, and information and free recruitment materials about career opportunities in chemistry technology.

  16. Chemistry Provision for Primary Pupils: The Experiences of 10 Years of Bristol ChemLabs Outreach

    ERIC Educational Resources Information Center

    Harrison, Timothy G.; Shallcross, Dudley E.

    2016-01-01

    Bristol ChemLabS, the UK's Centre for Excellence in Teaching and Learning in practical chemistry, delivers numerous outreach activity days per year for thousands of primary school pupils annually. These mainly comprise demonstration assemblies and hands on workshops for pupils in the main. The activities support the UK's Key Stage 2 science…

  17. ChemVoyage: A Web-Based, Simulated Learning Environment with Scaffolding and Linking Visualization to Conceptualization

    ERIC Educational Resources Information Center

    McRae, Christopher; Karuso, Peter; Liu, Fei

    2012-01-01

    The Web is now a standard tool for information access and dissemination in higher education. The prospect of Web-based, simulated learning platforms and technologies, however, remains underexplored. We have developed a Web-based tutorial program (ChemVoyage) for a third-year organic chemistry class on the topic of pericyclic reactions to…

  18. Immunochemical detection of food-derived isothiocyanate as a lysine conjugate.

    PubMed

    Nakamura, Toshiyuki; Kitamoto, Noritoshi; Osawa, Toshihiko; Kato, Yoji

    2010-01-01

    In a previous study we prepared monoclonal antibody against allyl isothiocyanate (AITC)-modified lysine (Lys), and found that AITC reacted with Lys under physiological conditions in vitro (T. Nakamura et al., Chem. Res. Toxicol., 22, 536-542 (2009)). In the present study, antibodies against benzyl isothiocyanate (ITC), 6-methylsulfinylhexyl ITC and phenethyl ITC modified protein were prepared, and the respective monoclonal antibodies, B6C9, 6MS3D10, and PE3A10 were obtained. These antibodies were applied to ITC detection in food using shredded Wasabia japonica (wasabi) and ground Carica papaya (papaya) seed by trapping ITC with biotin-labeled bovine serum albumin. ITC formation from the wasabi and papaya seed samples was confirmed using the antibodies in a dose-dependent manner. These antibodies might be applicable in identifying food-derived ITC.

  19. Design and Analysis of a Preconcentrator for the ChemLab

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    WONG,CHUNGNIN C.; FLEMMING,JEB H.; MANGINELL,RONALD P.

    2000-07-17

    Preconcentration is a critical analytical procedure when designing a microsystem for trace chemical detection, because it can purify a sample mixture and boost the small analyte concentration to a much higher level allowing a better analysis. This paper describes the development of a micro-fabricated planar preconcentrator for the {mu}ChemLab{trademark} at Sandia. To guide the design, an analytical model to predict the analyte transport, adsorption and resorption process in the preconcentrator has been developed. Experiments have also been conducted to analyze the adsorption and resorption process and to validate the model. This combined effort of modeling, simulation, and testing has ledmore » us to build a reliable, efficient preconcentrator with good performance.« less

  20. Vertical Ozone Concentration Profiles in the Middle East: WRF-Chem Predictions vs. Balloon Measurements

    NASA Astrophysics Data System (ADS)

    Fountoukis, C.; Ayoub, M.; Ackermann, L.; Gladich, I.; Hoehn, R.

    2017-12-01

    The greater Middle Eastern area is made up by more than 20 countries with over 400 million inhabitants. Due to extensive land conversion, intense industrialization and rapid urban population growth in recent years, the region's air quality is changing. High ozone levels affected by free tropospheric subsidence, long range transport and local production in large metropolitan areas of the region are of major concern. In this study we analyze data from i) continuously (24/7) operated ground monitoring stations, and ii) an ozonesonde station, operated in Doha by the Qatar Environment and Energy Research Institute coupled with simulations using a three-dimensional regional air quality model (WRF-Chem). Ozonesondes were launched at 1300 LT (1000 UTC) weekly during a summertime month (August 2015) representative of extremely hot and humid atmospheric conditions and a wintertime period (January/February 2016) of cool and dry conditions in the area. This is the first application of WRF-Chem in the Middle East focusing on vertical ozone concentrations on the lower troposphere (0 - 6 km) combined with high frequency vertical measurement (balloon) data. A triple nested model configuration has been selected with high spatial resolution over the domain of interest (2 × 2 km2). We examine different meteorological regimes and test the sensitivity of model predictions to planetary boundary layer parameterizations. Comparison of model predictions against observations show high correlation coefficients and encouragingly low biases in all meteorological variables. During wintertime, ozone is overall well predicted (Fractional Bias = -0.1) while the summertime comparison is more challenging. We suggest that the YSU scheme is more representative of the region and should be the scheme of choice in future WRF-Chem applications in the Middle East. Furthermore, we highlight the importance of revising the available anthropogenic emission inventory to account rapidly-changing urban

  1. Application of WRF/Chem over East Asia: Part I. Model evaluation and intercomparison with MM5/CMAQ

    NASA Astrophysics Data System (ADS)

    Zhang, Yang; Zhang, Xin; Wang, Litao; Zhang, Qiang; Duan, Fengkui; He, Kebin

    2016-01-01

    In this work, the application of the online-coupled Weather Research and Forecasting model with chemistry (WRF/Chem) version 3.3.1 is evaluated over East Asia for January, April, July, and October 2005 and compared with results from a previous application of an offline model system, i.e., the Mesoscale Model and Community Multiple Air Quality modeling system (MM5/CMAQ). The evaluation of WRF/Chem is performed using multiple observational datasets from satellites and surface networks in mainland China, Hong Kong, Taiwan, and Japan. WRF/Chem simulates well specific humidity (Q2) and downward longwave and shortwave radiation (GLW and GSW) with normalized mean biases (NMBs) within 24%, but shows moderate to large biases for temperature at 2-m (T2) (NMBs of -9.8% to 75.6%) and precipitation (NMBs of 11.4-92.7%) for some months, and wind speed at 10-m (WS10) (NMBs of 66.5-101%), for all months, indicating some limitations in the YSU planetary boundary layer scheme, the Purdue Lin cloud microphysics, and the Grell-Devenyi ensemble scheme. WRF/Chem can simulate the column abundances of gases reasonably well with NMBs within 30% for most months but moderately to significantly underpredicts the surface concentrations of major species at all sites in nearly all months with NMBs of -72% to -53.8% for CO, -99.4% to -61.7% for NOx, -84.2% to -44.5% for SO2, -63.9% to -25.2% for PM2.5, and -68.9% to 33.3% for PM10, and aerosol optical depth in all months except for October with NMBs of -38.7% to -16.2%. The model significantly overpredicts surface concentrations of O3 at most sites in nearly all months with NMBs of up to 160.3% and NO3- at the Tsinghua site in all months. Possible reasons for large underpredictions include underestimations in the anthropogenic emissions of CO, SO2, and primary aerosol, inappropriate vertical distributions of emissions of SO2 and NO2, uncertainties in upper boundary conditions (e.g., for O3 and CO), missing or inaccurate model representations (e

  2. Increasing Selenium and Yellow Pigment Concentrations in Foxtail Millet (Setaria italica L.) Grain with Foliar Application of Selenite.

    PubMed

    Ning, Na; Yuan, Xiang-Yang; Dong, Shu-Qi; Wen, Yin-Yuan; Gao, Zhen-Pan; Guo, Mei-Jun; Guo, Ping-Yi

    2016-03-01

    Although addition of selenium (Se) is known to increase Se in crops, it is unclear whether exogenous Se is linked to nutritional and functional components in foxtail millet (Setaria italica L.). In this study, we examined the potential of increasing Se and yellow pigment (YP) in foxtail millet grain by foliar application of Se. Field experiments were conducted during the growing season of foxtail millet in 2013 and 2014 to assess the effects of foliar spray of sodium selenite (10-210 g Se ha(-1)) on the yield, Se uptake and accumulation, total YP, and microminerals in the grain. Average grain yields with Se application were 5.60 and 4.53 t ha(-1) in the 2 years, showing no significant differences from the unfertilized control. However, grain Se concentration increased linearly with Se application rate, by 8.92 and 6.09 μg kg(-1) in the 2 years with application of 1 g Se ha(-1) (maximum grain recovery rates of Se fertilizer, 52 and 28 %). Likewise, total grain YP concentration markedly increased by 0.038 and 0.031 mg kg(-1) in the 2 years with application of 1 g Se ha(-1). Grain Mn, Cu, Fe, and Zn concentrations were not significantly affected by Se application. This study indicated that foliar application of Se effectively and reliably increased the concentrations of Se and YP in foxtail millet grain without affecting the yield or mineral micronutrient concentrations. Thus, foliar-applied selenite has a significant potential to increase the concentrations of selenium and YP (putative lutein (Shen, J Cereal Sci 61:86-93, 2015; Abdel-Aal, Cereal Chem 79:455-457, 2002; Abdel-Aal, J Agric Food Chem 55:787-794, 2007)) of foxtail millet and, thus, the health benefits of this crop.

  3. Comment on ``The application of the thermodynamic perturbation theory to study the hydrophobic hydration'' [J. Chem. Phys. 139, 024101 (2013)

    NASA Astrophysics Data System (ADS)

    Graziano, Giuseppe

    2013-09-01

    It is shown that the behaviour of the hydration thermodynamic functions obtained in the 3D Mercedes-Benz model of water by Mohoric et al. [J. Chem. Phys. 139, 024101 (2013)] is not qualitatively correct with respect to experimental data for a solute whose diameter is 1.5-fold larger than that of a water molecule. It is also pointed out that the failure is due to the fact that the used 3D Mercedes-Benz model of water [A. Bizjak, T. Urbic, V. Vlachy, and K. A. Dill, J. Chem. Phys. 131, 194504 (2009)] does not reproduce in a quantitatively correct manner the peculiar temperature dependence of water density.

  4. Assessing the CAM5 Physics Suite in the WRF-Chem Model: Implementation, Resolution Sensitivity, and a First Evaluation for a Regional Case Study

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ma, Po-Lun; Rasch, Philip J.; Fast, Jerome D.

    A suite of physical parameterizations (deep and shallow convection, turbulent boundary layer, aerosols, cloud microphysics, and cloud fraction) from the global climate model Community Atmosphere Model version 5.1 (CAM5) has been implemented in the regional model Weather Research and Forecasting with chemistry (WRF-Chem). A downscaling modeling framework with consistent physics has also been established in which both global and regional simulations use the same emissions and surface fluxes. The WRF-Chem model with the CAM5 physics suite is run at multiple horizontal resolutions over a domain encompassing the northern Pacific Ocean, northeast Asia, and northwest North America for April 2008 whenmore » the ARCTAS, ARCPAC, and ISDAC field campaigns took place. These simulations are evaluated against field campaign measurements, satellite retrievals, and ground-based observations, and are compared with simulations that use a set of common WRF-Chem Parameterizations. This manuscript describes the implementation of the CAM5 physics suite in WRF-Chem provides an overview of the modeling framework and an initial evaluation of the simulated meteorology, clouds, and aerosols, and quantifies the resolution dependence of the cloud and aerosol parameterizations. We demonstrate that some of the CAM5 biases, such as high estimates of cloud susceptibility to aerosols and the underestimation of aerosol concentrations in the Arctic, can be reduced simply by increasing horizontal resolution. We also show that the CAM5 physics suite performs similarly to a set of parameterizations commonly used in WRF-Chem, but produces higher ice and liquid water condensate amounts and near-surface black carbon concentration. Further evaluations that use other mesoscale model parameterizations and perform other case studies are needed to infer whether one parameterization consistently produces results more consistent with observations.« less

  5. Diversity of Rock Compositions at Gale Crater Observed by ChemCam and APXS on Curiosity, and Comparison to Meteorite and Orbital Observations

    NASA Astrophysics Data System (ADS)

    Wiens, R. C.; Maurice, S.; Grotzinger, J. P.; Gellert, R.; Mangold, N.; Sautter, V.; Ollila, A.; Dyar, M. D.; Le Mouelic, S.; Ehlmann, B. L.; Clegg, S. M.; Lanza, N.; Cousin, A.; Forni, O.; Gasnault, O.; Lasue, J.; Blaney, D. L.; Newsom, H. E.; Herkenhoff, K. E.; Anderson, R. B.; D'Uston, L.; Bridges, N. T.; Fabre, C.; Meslin, P.; Johnson, J.; Vaniman, D.; Bridges, J.; Dromart, G.; Schmidt, M. E.; Team, M.

    2013-12-01

    Gale crater was selected as the Curiosity landing site because of the apparent sedimentary spectral signatures seen from orbit. Sedimentary materials on Mars have to this point showed very little expression of major element mobility, so compositions of precursor igneous minerals play a strong role in the compositions of sediments. In addition, pebbles and float rocks on Bradbury Rise (sols 0-50, > 324) appear to be mostly igneous in origin, and are assumed to have been carried down from the crater rim. Overall in the first year on Mars ChemCam obtained >75,000 LIBS spectra on > 2,000 observation points, supported by > 1,000 RMI images, and APXS obtained a significant number of observations. These show surprisingly variable compositions. The mean ChemCam compositions for Bradbury Rise dust-free rocks and pebbles (62 locations) give SiO2 = 56%, FeOT = 16% and show high alkalis consistent with Jake Matijevic (sol ~47) APXS Na2O ~6.6 wt%. ChemCam observations on the conglomerate Link (sol 27) gave Rb > 150 ppm and Sr > 1500 ppm. These compositions imply the presence of abundant alkali feldspars in the material infilling the lower parts of Gale crater. They are generally consistent with the more feldspar-rich SNC meteorites but show a radical departure from larger scale orbital observations, e.g., GRS, raising the question of how widespread these compositions are outside of Gale crater. Sedimentary materials at Yellowknife Bay encompassing the Sheepbed (sols 125-300) and Shaler (sols 121, 311-324) units, potentially including Point Lake (sols 301-310) and Rocknest (sols 57-97), appear to have incorporated varying amounts of igneous source materials. Seven rocks investigated at Rocknest show significant additions of Fe, with mean FeOT = 25% (154 locations), suggesting that FeO was a cementing agent. ChemCam observations at Shaler show varying amounts of alkali feldspar (i.e., related to Bradbury Rise), Fe-rich material (Rocknest-like), and potassium-rich material

  6. FastChem: A computer program for efficient complex chemical equilibrium calculations in the neutral/ionized gas phase with applications to stellar and planetary atmospheres

    NASA Astrophysics Data System (ADS)

    Stock, Joachim W.; Kitzmann, Daniel; Patzer, A. Beate C.; Sedlmayr, Erwin

    2018-06-01

    For the calculation of complex neutral/ionized gas phase chemical equilibria, we present a semi-analytical versatile and efficient computer program, called FastChem. The applied method is based on the solution of a system of coupled nonlinear (and linear) algebraic equations, namely the law of mass action and the element conservation equations including charge balance, in many variables. Specifically, the system of equations is decomposed into a set of coupled nonlinear equations in one variable each, which are solved analytically whenever feasible to reduce computation time. Notably, the electron density is determined by using the method of Nelder and Mead at low temperatures. The program is written in object-oriented C++ which makes it easy to couple the code with other programs, although a stand-alone version is provided. FastChem can be used in parallel or sequentially and is available under the GNU General Public License version 3 at https://github.com/exoclime/FastChem together with several sample applications. The code has been successfully validated against previous studies and its convergence behavior has been tested even for extreme physical parameter ranges down to 100 K and up to 1000 bar. FastChem converges stable and robust in even most demanding chemical situations, which posed sometimes extreme challenges for previous algorithms.

  7. The "Virtual ChemLab" Project: A Realistic and Sophisticated Simulation of Organic Synthesis and Organic Qualitative Analysis

    ERIC Educational Resources Information Center

    Woodfield, Brian F.; Andrus, Merritt B.; Waddoups, Gregory L.; Moore, Melissa S.; Swan, Richard; Allen, Rob; Bodily, Greg; Andersen, Tricia; Miller, Jordan; Simmons, Bryon; Stanger, Richard

    2005-01-01

    A set of sophisticated and realistic laboratory simulations is created for use in freshman- and sophomore-level chemistry classes and laboratories called 'Virtual ChemLab'. A detailed assessment of student responses is provided and the simulation's pedagogical utility is described using the organic simulation.

  8. The ChemCam Remote Micro-Imager at Gale crater: Review of the first year of operations on Mars

    NASA Astrophysics Data System (ADS)

    Le Mouélic, S.; Gasnault, O.; Herkenhoff, K. E.; Bridges, N. T.; Langevin, Y.; Mangold, N.; Maurice, S.; Wiens, R. C.; Pinet, P.; Newsom, H. E.; Deen, R. G.; Bell, J. F.; Johnson, J. R.; Rapin, W.; Barraclough, B.; Blaney, D. L.; Deflores, L.; Maki, J.; Malin, M. C.; Pérez, R.; Saccoccio, M.

    2015-03-01

    The Mars Science Laboratory rover, "Curiosity" landed near the base of a 5 km-high mound of layered material in Gale crater. Mounted on the rover mast, the ChemCam instrument is designed to remotely determine the composition of soils and rocks located a few meters from the rover, using a Laser-Induced Breakdown Spectrometer (LIBS) coupled to a Remote Micro-Imager (RMI). We provide an overview of the diverse imaging investigations that were carried out by ChemCam's RMI during the first year of operation on Mars. 1182 individual panchromatic RMI images were acquired from Sol 10 to Sol 360 to document the ChemCam LIBS measurements and to characterize soils, rocks and rover hardware. We show several types of derived imaging products, including mosaics of images taken before and after laser shots, difference images to enhance the most subtle laser pits, merges with color Mastcam-100 images, micro-topography using the Z-stack technique, and time lapse movies. The very high spatial resolution of RMI is able to resolve rock textures at sub-mm scales, which provides clues regarding the origin (igneous versus sedimentary) of rocks, and to reveal information about their diagenetic and weathering evolution. In addition to its scientific value over the range accessible by LIBS (1-7 m), we also show that RMI can also serve as a powerful long distance reconnaissance tool to characterize the landscape at distances up to several kilometers from the rover.

  9. Operational forecast products and applications based on WRF/Chem

    NASA Astrophysics Data System (ADS)

    Hirtl, Marcus; Flandorfer, Claudia; Langer, Matthias; Mantovani, Simone; Olefs, Marc; Schellander-Gorgas, Theresa

    2015-04-01

    The responsibilities of the national weather service of Austria (ZAMG) include the support of the federal states and the public in questions connected to the protection of the environment in the frame of advisory and counseling services as well as expert opinions. The ZAMG conducts daily Air-Quality forecasts using the on-line coupled model WRF/Chem. The mother domain expands over Europe, North Africa and parts of Russia. The nested domain includes the alpine region and has a horizontal resolution of 4 km. Local emissions (Austria) are used in combination with European inventories (TNO and EMEP) for the simulations. The modeling system is presented and the results from the evaluation of the assimilation of pollutants using the 3D-VAR software GSI is shown. Currently observational data (PM10 and O3) from the Austrian Air-Quality network and from European stations (EEA) are assimilated into the model on an operational basis. In addition PM maps are produced using Aerosol Optical Thickness (AOT) observations from MODIS in combination with model data using machine learning techniques. The modeling system is operationally evaluated with different data sets. The emphasis of the application is on the forecast of pollutants which are compared to the hourly values (PM10, O3 and NO2) of the Austrian Air-Quality network. As the meteorological conditions are important for transport and chemical processes, some parameters like wind and precipitation are automatically evaluated (SAL diagrams, maps, …) with other models (e.g. ECMWF, AROME, …) and ground stations via web interface. The prediction of the AOT is also important for operators of solar power plants. In the past Numerical Weather Prediction (NWP) models were used to predict the AOT based on cloud forecasts at the ZAMG. These models do not consider the spatial and temporal variation of the aerosol distribution in the atmosphere with a consequent impact on the accuracy of forecasts especially during clear-sky days

  10. Chemistry Outreach Project to High Schools Using a Mobile Chemistry Laboratory, ChemKits, and Teacher Workshops

    ERIC Educational Resources Information Center

    Long, Gary L.; Bailey, Carol A.; Bunn, Barbara B.; Slebodnick, Carla; Johnson, Michael R.; Derozier, Shad

    2012-01-01

    The Chemistry Outreach Program (ChOP) of Virginia Tech was a university-based outreach program that addressed the needs of high school chemistry classes in underfunded rural and inner-city school districts. The primary features of ChOP were a mobile chemistry laboratory (MCL), a shipping-based outreach program (ChemKits), and teacher workshops.…

  11. WRF and WRF-Chem v3.5.1 simulations of meteorology and black carbon concentrations in the Kathmandu Valley

    NASA Astrophysics Data System (ADS)

    Mues, Andrea; Lauer, Axel; Lupascu, Aurelia; Rupakheti, Maheswar; Kuik, Friderike; Lawrence, Mark G.

    2018-06-01

    An evaluation of the meteorology simulated using the Weather Research and Forecast (WRF) model for the region of south Asia and Nepal with a focus on the Kathmandu Valley is presented. A particular focus of the model evaluation is placed on meteorological parameters that are highly relevant to air quality such as wind speed and direction, boundary layer height and precipitation. The same model setup is then used for simulations with WRF including chemistry and aerosols (WRF-Chem). A WRF-Chem simulation has been performed using the state-of-the-art emission database, EDGAR HTAP v2.2, which is the Emission Database for Global Atmospheric Research of the Joint Research Centre (JRC) of the European Commission, in cooperation with the Task Force on Hemispheric Transport of Air Pollution (TF HTAP) organized by the United Nations Economic Commission for Europe, along with a sensitivity simulation using observation-based black carbon emission fluxes for the Kathmandu Valley. The WRF-Chem simulations are analyzed in comparison to black carbon measurements in the valley and to each other. The evaluation of the WRF simulation with a horizontal resolution of 3×3 km2 shows that the model is often able to capture important meteorological parameters inside the Kathmandu Valley and the results for most meteorological parameters are well within the range of biases found in other WRF studies especially in mountain areas. But the evaluation results also clearly highlight the difficulties of capturing meteorological parameters in such complex terrain and reproducing subgrid-scale processes with a horizontal resolution of 3×3 km2. The measured black carbon concentrations are typically systematically and strongly underestimated by WRF-Chem. A sensitivity study with improved emissions in the Kathmandu Valley shows significantly reduced biases but also underlines several limitations of such corrections. Further improvements of the model and of the emission data are needed before being

  12. Regional Modeling of Dust Mass Balance and Radiative Forcing over East Asia using WRF-Chem

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Chen, Siyu; Zhao, Chun; Qian, Yun

    The Weather Research and Forecasting model with Chemistry (WRF-Chem) is used to investigate the seasonal and annual variations of mineral dust over East Asia during 2007-2011, with a focus on the dust mass balance and radiative forcing. A variety of measurements from in-stu and satellite observations have been used to evaluate simulation results. Generally, WRF-Chem reproduces not only the column variability but also the vertical profile and size distribution of mineral dust over and near the dust source regions of East Asia. We investigate the dust lifecycle and the factors that control the seasonal and spatial variations of dust massmore » balance and radiative forcing over the seven sub-regions of East Asia, i.e. source regions, the Tibetan Plateau, Northern China, Southern China, the ocean outflow region, and Korea-Japan regions. Results show that, over the source regions, transport and dry deposition are the two dominant sinks. Transport contributes to ~30% of the dust sink over the source regions. Dust results in a surface cooling of up to -14 and -10 W m-2, atmospheric warming of up to 20 and 15 W m-2, and TOA cooling of -5 and -8 W m-2 over the two major dust source regions of East Asia, respectively. Over the Tibetan Plateau, transport is the dominant source with a peak in summer. Over identified outflow regions, maximum dust mass loading in spring is contributed by the transport. Dry and wet depositions are the comparably dominant sinks, but wet deposition is larger than dry deposition over the Korea-Japan region, particularly in spring (70% versus 30%). The WRF-Chem simulations can generally capture the measured features of dust aerosols and its radaitve properties and dust mass balance over East Asia, which provides confidence for use in further investigation of dust impact on climate over East Asia.« less

  13. Characterising Biomass Burning Aerosol in WRF-Chem using the Volatility Basis Set, with Evaluation against SAMBBA Flight Data

    NASA Astrophysics Data System (ADS)

    Lowe, D.; Topping, D. O.; Archer-Nicholls, S.; Darbyshire, E.; Morgan, W.; Liu, D.; Allan, J. D.; Coe, H.; McFiggans, G.

    2015-12-01

    The burning of forests in the Amazonia region is a globally significant source of carbonaceous aerosol, containing both absorbing and scattering components [1]. In addition biomass burning aerosol (BBA) are also efficient cloud condensation nuclei (CCN), modifying cloud properties and influencing atmospheric circulation and precipitation tendencies [2]. The impacts of BBA are highly dependent on their size distribution and composition. A bottom-up emissions inventory, the Brazilian Biomass Burning Emissions Model (3BEM) [3], utilising satellite products to generate daily fire emission maps is used. Injection of flaming emissions within the atmospheric column is simulated using both a sub-grid plume-rise parameterisation [4], and simpler schemes, within the Weather Research and Forecasting Model with Chemistry (WRF-Chem, v3.4.1) [5]. Aerosol dynamics are simulated using the sectional MOSAIC scheme [6], incorporating a volatility basis set (VBS) treatment of organic aerosol [7]. For this work we have modified the 9-bin VBS to use the biomass burning specific scheme developed by May et al. [8]. The model has been run for September 2012 over South America (at a 25km resolution). We will present model results evaluating the modelled aerosol vertical distribution, size distribution, and composition against measurements taken by the FAAM BAe-146 research aircraft during the SAMBBA campaign. The main focus will be on investigating the factors controlling the vertical gradient of the organic mass to black carbon ratio of the measured aerosol. This work is supported by the Nature Environment Research Council (NERC) as part of the SAMBBA project under grant NE/J010073/1. [1] D. G. Streets et al., 2004, J. Geophys. Res., 109, D24212. [2] M. O. Andreae et al., 2004, Science, 303, 1337-1342. [3] K. Longo et al., 2010, Atmos. Chem. Phys., 10, 5,785-5,795. [4] S. Freitas et al., 2007, Atmos. Chem. Phys., 7, 3,385-3,398. [5] S. Archer-Nicholls et al., 2015, Geosci. Model Dev., 8

  14. Spectroscopic Observations of Comet C/2013 A1 (Siding Spring) from Mars using ChemCam, OMEGA and SPICAM.

    NASA Astrophysics Data System (ADS)

    Lasue, J.; Gondet, B.; Bertaux, J. L.; Barraclough, B. L.; Beck, P.; Bender, S.; Bibring, J. P.; Bridges, N. T.; Chaufray, J. Y.; Gasnault, O.; Herkenhoff, K. E.; Langevin, Y.; Le Mouelic, S.; Lemmon, M. T.; Lewin, E.; McConnochie, T. H.; Martín-Torres, J.; Maurice, S.; Meslin, P. Y.; Ming, D. W.; Montmessin, F.; Owen, T. C.; Rapin, W.; Rocard, F.; Wiens, R. C.; Zorzano, M. P.

    2014-12-01

    Comet Siding Spring will graze Mars on Oct. 19th 2014. Its closest approach from the centre of the planet will be 135,000 km, and its predicted visual magnitude as low as -5.3 (JPL Horizons web site). The observing conditions will be ideal to attempt spectroscopic measurements of the inner coma from the UV to the IR at an unprecedented spectral resolution from the instruments located on and around Mars. ChemCam is a Laser-Induced Breakdown Spectroscopy instrument operating on-board the Mars Science Laboratory rover to analyse the chemical composition of rocks and can be used for passive spectroscopy. ChemCam is equipped with high resolution spectrometers covering the optical range (240-850 nm) with a pixel resolution of 0.05nm up to 470nm and 0.2nm in the near-IR range. The ChemCam passive spectroscopy field of view is 0.65 mrad wide and covers several 100km projected on the coma. Based on predicted magnitude and inner coma intensity variations, we expect to retrieve spectral signatures around the nucleus. Simultaneously the 7 instruments on board Mars Express will take measurements in nadir and limb modes. We will merge the results obtained with ChemCam with those of the 2 imaging spectrometers SPICAM (110-310 nm resolution of 0.6nm and 1-1.7 μm resolution of 1.5 nm) and OMEGA (457-910 nm resolution of 1.5 nm and 2.5-5.1 μm resolution of 15 nm) to obtain the composition and spatial variation of emitting molecules in the different parts of the coma. The instruments will also monitor the atmosphere before and after the encounter to detect any change. We will report on the preparations for the observations and the spectroscopy results, with emphasis on the detection of complex organic molecules and the spatial distribution of H2O and OH in the inner coma. A decision will be made on the adequacy of risk reduction activities for the spacecraft, and planned science operations may need to be cancelled by ESOC.This work is supported by NASA, ESA and CNES.

  15. Evaluation of the Chem 1 analyzer.

    PubMed

    Biosca, C; Antoja, F; Sierra, C; Aluma, A; Farre, J; Alsina, M J; Galimany, R

    1991-01-01

    The selective multitest Technicon Chem 1 analyser was evaluated according to the guidelines of the 'Comisión de Instrumentación de la Sociedad Española de Química Clínica', and the protocols of the 'European Committee for Clinical Laboratory Standards' and 'Commission de validation de techniques' of the 'Société Française de Biologie Clinique'. The evaluation was performed in three steps: evaluation in routine conditions, assessment of the interferences and study of practicability. Under routine working conditions, eighteen constituents were studied. Within-run imprecision ranged from 0.6% (CV) for gamma-GT to 4.7% (CV) for AST. Between-run imprecision ranged from 1.6% (CV) for ion sodium to 5.5% (CV) for creatinine. Specimen related carry-over was not within the samples; specimen independent carry-over was found in some of the constituents studied. The relative inaccuracy is good for all the constituents assayed. Haemoglobin (290 mumol.l1) showed a positive interference with urate at three concentration levels (low, medium and high). Bilirubin (up to 300 mumol.l-1) caused a negative interference with creatinine at three concentration levels. Turbidity (trigliceride up to 4 mumol.l-1) stated a positive interference with creatinine at three concentration levels and with AST at two concentration levels (low and medium). Turbidity also caused a negative interference with urate at three concentration levels and with urea at two concentration levels (low and medium).

  16. AerChemMIP: Quantifying the effects of chemistry and aerosols in CMIP6

    DOE PAGES

    Collins, William J.; Lamarque, Jean -François; Schulz, Michael; ...

    2017-02-09

    The Aerosol Chemistry Model Intercomparison Project (AerChemMIP) is endorsed by the Coupled-Model Intercomparison Project 6 (CMIP6) and is designed to quantify the climate and air quality impacts of aerosols and chemically reactive gases. These are specifically near-term climate forcers (NTCFs: methane, tropospheric ozone and aerosols, and their precursors), nitrous oxide and ozone-depleting halocarbons. The aim of AerChemMIP is to answer four scientific questions. 1. How have anthropogenic emissions contributed to global radiative forcing and affected regional climate over the historical period? 2. How might future policies (on climate, air quality and land use) affect the abundances of NTCFs and theirmore » climate impacts? 3.How do uncertainties in historical NTCF emissions affect radiative forcing estimates? 4. How important are climate feedbacks to natural NTCF emissions, atmospheric composition, and radiative effects? These questions will be addressed through targeted simulations with CMIP6 climate models that include an interactive representation of tropospheric aerosols and atmospheric chemistry. These simulations build on the CMIP6 Diagnostic, Evaluation and Characterization of Klima (DECK) experiments, the CMIP6 historical simulations, and future projections performed elsewhere in CMIP6, allowing the contributions from aerosols and/or chemistry to be quantified. As a result, specific diagnostics are requested as part of the CMIP6 data request to highlight the chemical composition of the atmosphere, to evaluate the performance of the models, and to understand differences in behaviour between them.« less

  17. Statistical Downscaling of WRF-Chem Model: An Air Quality Analysis over Bogota, Colombia

    NASA Astrophysics Data System (ADS)

    Kumar, Anikender; Rojas, Nestor

    2015-04-01

    Statistical downscaling is a technique that is used to extract high-resolution information from regional scale variables produced by coarse resolution models such as Chemical Transport Models (CTMs). The fully coupled WRF-Chem (Weather Research and Forecasting with Chemistry) model is used to simulate air quality over Bogota. Bogota is a tropical Andean megacity located over a high-altitude plateau in the middle of very complex terrain. The WRF-Chem model was adopted for simulating the hourly ozone concentrations. The computational domains were chosen of 120x120x32, 121x121x32 and 121x121x32 grid points with horizontal resolutions of 27, 9 and 3 km respectively. The model was initialized with real boundary conditions using NCAR-NCEP's Final Analysis (FNL) and a 1ox1o (~111 km x 111 km) resolution. Boundary conditions were updated every 6 hours using reanalysis data. The emission rates were obtained from global inventories, namely the REanalysis of the TROpospheric (RETRO) chemical composition and the Emission Database for Global Atmospheric Research (EDGAR). Multiple linear regression and artificial neural network techniques are used to downscale the model output at each monitoring stations. The results confirm that the statistically downscaled outputs reduce simulated errors by up to 25%. This study provides a general overview of statistical downscaling of chemical transport models and can constitute a reference for future air quality modeling exercises over Bogota and other Colombian cities.

  18. AerChemMIP: Quantifying the effects of chemistry and aerosols in CMIP6

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Collins, William J.; Lamarque, Jean -François; Schulz, Michael

    The Aerosol Chemistry Model Intercomparison Project (AerChemMIP) is endorsed by the Coupled-Model Intercomparison Project 6 (CMIP6) and is designed to quantify the climate and air quality impacts of aerosols and chemically reactive gases. These are specifically near-term climate forcers (NTCFs: methane, tropospheric ozone and aerosols, and their precursors), nitrous oxide and ozone-depleting halocarbons. The aim of AerChemMIP is to answer four scientific questions. 1. How have anthropogenic emissions contributed to global radiative forcing and affected regional climate over the historical period? 2. How might future policies (on climate, air quality and land use) affect the abundances of NTCFs and theirmore » climate impacts? 3.How do uncertainties in historical NTCF emissions affect radiative forcing estimates? 4. How important are climate feedbacks to natural NTCF emissions, atmospheric composition, and radiative effects? These questions will be addressed through targeted simulations with CMIP6 climate models that include an interactive representation of tropospheric aerosols and atmospheric chemistry. These simulations build on the CMIP6 Diagnostic, Evaluation and Characterization of Klima (DECK) experiments, the CMIP6 historical simulations, and future projections performed elsewhere in CMIP6, allowing the contributions from aerosols and/or chemistry to be quantified. As a result, specific diagnostics are requested as part of the CMIP6 data request to highlight the chemical composition of the atmosphere, to evaluate the performance of the models, and to understand differences in behaviour between them.« less

  19. Assessing regional scale predictions of aerosols, marine stratocumulus, and their interactions during VOCALS-REx using WRF-Chem

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Yang, Qing; Gustafson, William I.; Fast, Jerome D.

    2011-12-02

    In the recent chemistry version (v3.3) of the Weather Research and Forecasting (WRF-Chem) model, we have coupled the Morrison double-moment microphysics scheme with interactive aerosols so that full two-way aerosol-cloud interactions are included in simulations. We have used this new WRF-Chem functionality in a study focused on assessing predictions of aerosols, marine stratocumulus clouds, and their interactions over the Southeast Pacific using measurements from the VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx) and satellite retrievals. This study also serves as a detailed analysis of our WRF-Chem simulations contributed to the VOCALS model Assessment (VOCA) project. The WRF-Chem 31-day (October 15-November 16,more » 2008) simulation with aerosol-cloud interactions (AERO hereafter) is also compared to a simulation (MET hereafter) with fixed cloud droplet number concentrations assumed by the default in Morrison microphysics scheme with no interactive aerosols. The well-predicted aerosol properties such as number, mass composition, and optical depth lead to significant improvements in many features of the predicted stratocumulus clouds: cloud optical properties and microphysical properties such as cloud top effective radius, cloud water path, and cloud optical thickness, and cloud macrostructure such as cloud depth and cloud base height. These improvements in addition to the aerosol direct and semi-direct effects, in turn, feed back to the prediction of boundary-layer characteristics and energy budgets. Particularly, inclusion of interactive aerosols in AERO strengths temperature and humidity gradients within capping inversion layer and lowers the MBL depth by 150 m from that of the MET simulation. Mean top-of-the-atmosphere outgoing shortwave fluxes, surface latent heat, and surface downwelling longwave fluxes are in better agreement with observations in AERO, compared to the MET simulation. Nevertheless, biases in some of the simulated

  20. Superfund Record of Decision (EPA Region 5): Enviro-Chem (Northside Sanitary Landfill), Zionsville, IN. (First remedial action), (Amendment), June 1991. Final report

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Not Available

    The Enviro-chem site is a former waste recovery/reclamation/brokerage facility in Boone County, Indiana. Adjacent to the site is another Superfund site, the Northside Sanitary Landfill (NSL) which, prior to the Record of Decision (ROD) amendment, was to be remediated in a combined remedy for both sites. Land use in the area is agricultural and residential to the north and west. In May 1982, the State ordered Enviro-Chem to close and environmentally secure the site because it failed to reduce hazardous waste inventories. Subsequently, two emergency removal actions were conducted to remove the major sources of contamination. The ROD amends themore » 1987 ROD and provides a comprehensive site remedy for the Enviro-Chem site addressing source control instead of ground water remediation. The primary contaminants of concern affecting the soil are VOCs including PCE, TCE, toluene; and other organics including phenols. The amended remedial action for the site includes treating contaminated soil onsite using soil vapor extraction with a granulated activated carbon system to control the extracted vapor and implementing a contingent remedy for a subsurface ground water collection and treatment system.« less

  1. Top-down estimate of dust emissions through integration of MODIS and MISR aerosol retrievals with the GEOS-Chem adjoint model

    NASA Astrophysics Data System (ADS)

    Wang, Jun; Xu, Xiaoguang; Henze, Daven K.; Zeng, Jing; Ji, Qiang; Tsay, Si-Chee; Huang, Jianping

    2012-04-01

    Predicting the influences of dust on atmospheric composition, climate, and human health requires accurate knowledge of dust emissions, but large uncertainties persist in quantifying mineral sources. This study presents a new method for combined use of satellite-measured radiances and inverse modeling to spatially constrain the amount and location of dust emissions. The technique is illustrated with a case study in May 2008; the dust emissions in Taklimakan and Gobi deserts are spatially optimized using the GEOS-Chem chemical transport model and its adjoint constrained by aerosol optical depth (AOD) that are derived over the downwind dark-surface region in China from MODIS (Moderate Resolution Imaging Spectroradiometer) reflectance with the aerosol single scattering properties consistent with GEOS-chem. The adjoint inverse modeling yields an overall 51% decrease in prior dust emissions estimated by GEOS-Chem over the Taklimakan-Gobi area, with more significant reductions south of the Gobi Desert. The model simulation with optimized dust emissions shows much better agreement with independent observations from MISR (Multi-angle Imaging SpectroRadiometer) AOD and MODIS Deep Blue AOD over the dust source region and surface PM10 concentrations. The technique of this study can be applied to global multi-sensor remote sensing data for constraining dust emissions at various temporal and spatial scales, and hence improving the quantification of dust effects on climate, air quality, and human health.

  2. Application of ChemDraw NMR Tool: Correlation of Program-Generated 13C Chemical Shifts and pKa Values of para-Substituted Benzoic Acids

    NASA Astrophysics Data System (ADS)

    Wang, Hongyi

    2005-09-01

    An application of ChemDraw NMR Tool was demonstrated by correlation of program-generated 13 C NMR chemical shifts and p K a values of para-substituted benzoic acids. Experimental 13 C NMR chemical shifts were analyzed in the same way for comparison. The project can be used as an assignment at the end of the first-year organic chemistry course to review topics or explore new techniques: Hammett equation, acid base equilibrium theory, electronic nature of functional groups, inductive and resonance effects, structure reactivity relationship, NMR spectroscopy, literature search, database search, and ChemDraw software.

  3. Simulating the impacts of chronic ozone exposure on plant conductance and photosynthesis, and on the regional hydroclimate using WRF/Chem

    NASA Astrophysics Data System (ADS)

    Li, Jialun; Mahalov, Alex; Hyde, Peter

    2016-11-01

    The Noah-Multiparameterization land surface model in the Weather Research and Forecasting (WRF) with Chemistry (WRF/Chem) is modified to include the effects of chronic ozone exposure (COE) on plant conductance and photosynthesis (PCP) found from field experiments. Based on the modified WRF/Chem, the effects of COE on regional hydroclimate have been investigated over the continental United States. Our results indicate that the model with/without modification in its current configuration can reproduce the rainfall and temperature patterns of the observations and reanalysis data, although it underestimates rainfall in the central Great Plains and overestimates it in the eastern coast states. The experimental tests on the effects of COE include setting different thresholds of ambient ozone concentrations ([O3]) and using different linear regressions to quantify PCP against the COE. Compared with the WRF/Chem control run (i.e., without considering the effects of COE), the modified model at different experiment setups improves the simulated estimates of rainfall and temperatures in Texas and regions to the immediate north. The simulations in June, July and August of 2007-2012 show that surface [O3] decrease latent heat fluxes (LH) by 10-27 W m-2, increase surface air temperatures (T 2) by 0.6 °C-2.0 °C, decrease rainfall by 0.9-1.4 mm d-1, and decrease runoff by 0.1-0.17 mm d-1 in Texas and surrounding areas, all of which highly depends on the precise experiment setup, especially the [O3] threshold. The mechanism producing these results is that COE decreases the LH and increases sensible heat fluxes, which in turn increases the Bowen ratios and air temperatures. This lowering of the LH also results in the decrease of convective potential and finally decreases convective rainfall. Employing this modified WRF/Chem model in any high [O3] region can improve the understanding of the interactions of vegetation, meteorology, chemistry/emissions, and crop productivity.

  4. Twelve-month, 12 km resolution North American WRF-Chem v3.4 air quality simulation: performance evaluation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tessum, C. W.; Hill, J. D.; Marshall, J. D.

    We present results from and evaluate the performance of a 12-month, 12 km horizontal resolution year 2005 air pollution simulation for the contiguous United States using the WRF-Chem (Weather Research and Forecasting with Chemistry) meteorology and chemical transport model (CTM). We employ the 2005 US National Emissions Inventory, the Regional Atmospheric Chemistry Mechanism (RACM), and the Modal Aerosol Dynamics Model for Europe (MADE) with a volatility basis set (VBS) secondary aerosol module. Overall, model performance is comparable to contemporary modeling efforts used for regulatory and health-effects analysis, with an annual average daytime ozone (O 3) mean fractional bias (MFB) ofmore » 12% and an annual average fine particulate matter (PM 2.5) MFB of −1%. WRF-Chem, as configured here, tends to overpredict total PM 2.5 at some high concentration locations and generally overpredicts average 24 h O 3 concentrations. Performance is better at predicting daytime-average and daily peak O 3 concentrations, which are more relevant for regulatory and health effects analyses relative to annual average values. Predictive performance for PM 2.5 subspecies is mixed: the model overpredicts particulate sulfate (MFB = 36%), underpredicts particulate nitrate (MFB = −110%) and organic carbon (MFB = −29%), and relatively accurately predicts particulate ammonium (MFB = 3%) and elemental carbon (MFB = 3%), so that the accuracy in total PM 2.5 predictions is to some extent a function of offsetting over- and underpredictions of PM 2.5 subspecies. Model predictive performance for PM 2.5 and its subspecies is in general worse in winter and in the western US than in other seasons and regions, suggesting spatial and temporal opportunities for future WRF-Chem model development and evaluation.« less

  5. Twelve-month, 12 km resolution North American WRF-Chem v3.4 air quality simulation: performance evaluation

    DOE PAGES

    Tessum, C. W.; Hill, J. D.; Marshall, J. D.

    2015-04-07

    We present results from and evaluate the performance of a 12-month, 12 km horizontal resolution year 2005 air pollution simulation for the contiguous United States using the WRF-Chem (Weather Research and Forecasting with Chemistry) meteorology and chemical transport model (CTM). We employ the 2005 US National Emissions Inventory, the Regional Atmospheric Chemistry Mechanism (RACM), and the Modal Aerosol Dynamics Model for Europe (MADE) with a volatility basis set (VBS) secondary aerosol module. Overall, model performance is comparable to contemporary modeling efforts used for regulatory and health-effects analysis, with an annual average daytime ozone (O 3) mean fractional bias (MFB) ofmore » 12% and an annual average fine particulate matter (PM 2.5) MFB of −1%. WRF-Chem, as configured here, tends to overpredict total PM 2.5 at some high concentration locations and generally overpredicts average 24 h O 3 concentrations. Performance is better at predicting daytime-average and daily peak O 3 concentrations, which are more relevant for regulatory and health effects analyses relative to annual average values. Predictive performance for PM 2.5 subspecies is mixed: the model overpredicts particulate sulfate (MFB = 36%), underpredicts particulate nitrate (MFB = −110%) and organic carbon (MFB = −29%), and relatively accurately predicts particulate ammonium (MFB = 3%) and elemental carbon (MFB = 3%), so that the accuracy in total PM 2.5 predictions is to some extent a function of offsetting over- and underpredictions of PM 2.5 subspecies. Model predictive performance for PM 2.5 and its subspecies is in general worse in winter and in the western US than in other seasons and regions, suggesting spatial and temporal opportunities for future WRF-Chem model development and evaluation.« less

  6. ChemEd Bridges: Building Bridges between Two-Year College Chemistry Faculty and the National Chemical Education Community

    ERIC Educational Resources Information Center

    Ungar, Harry; Brown, David R.

    2010-01-01

    ChemEd Bridges is an NSF-funded project that provides career and professional development opportunities for chemistry faculty members who teach at two-year colleges (2YCs). We broaden the interests and the horizons of these faculty members by building bridges between them and the broader community of chemical educators. In particular, we have…

  7. Comment on ``On the Crooks fluctuation theorem and the Jarzynski equality'' [J. Chem. Phys. 129, 091101 (2008)

    NASA Astrophysics Data System (ADS)

    Adib, Artur B.

    2009-06-01

    It has recently been argued that a self-consistency condition involving the Jarzynski equality (JE) and the Crooks fluctuation theorem (CFT) is violated for a simple Brownian process [L. Y. Chen, J. Chem. Phys.129, 091101 (2008)]. This note adopts the definitions in the original formulation of the JE and CFT and demonstrates the contrary.

  8. Exploring Natural Products from the Biodiversity of Pakistan for Computational Drug Discovery Studies: Collection, Optimization, Design and Development of A Chemical Database (ChemDP).

    PubMed

    Mirza, Shaher Bano; Bokhari, Habib; Fatmi, Muhammad Qaiser

    2015-01-01

    Pakistan possesses a rich and vast source of natural products (NPs). Some of these secondary metabolites have been identified as potent therapeutic agents. However, the medicinal usage of most of these compounds has not yet been fully explored. The discoveries for new scaffolds of NPs as inhibitors of certain enzymes or receptors using advanced computational drug discovery approaches are also limited due to the unavailability of accurate 3D structures of NPs. An organized database incorporating all relevant information, therefore, can facilitate to explore the medicinal importance of the metabolites from Pakistani Biodiversity. The Chemical Database of Pakistan (ChemDP; release 01) is a fully-referenced, evolving, web-based, virtual database which has been designed and developed to introduce natural products (NPs) and their derivatives from the biodiversity of Pakistan to Global scientific communities. The prime aim is to provide quality structures of compounds with relevant information for computer-aided drug discovery studies. For this purpose, over 1000 NPs have been identified from more than 400 published articles, for which 2D and 3D molecular structures have been generated with a special focus on their stereochemistry, where applicable. The PM7 semiempirical quantum chemistry method has been used to energy optimize the 3D structure of NPs. The 2D and 3D structures can be downloaded as .sdf, .mol, .sybyl, .mol2, and .pdb files - readable formats by many chemoinformatics/bioinformatics software packages. Each entry in ChemDP contains over 100 data fields representing various molecular, biological, physico-chemical and pharmacological properties, which have been properly documented in the database for end users. These pieces of information have been either manually extracted from the literatures or computationally calculated using various computational tools. Cross referencing to a major data repository i.e. ChemSpider has been made available for overlapping

  9. ChemEngine: harvesting 3D chemical structures of supplementary data from PDF files.

    PubMed

    Karthikeyan, Muthukumarasamy; Vyas, Renu

    2016-01-01

    Digital access to chemical journals resulted in a vast array of molecular information that is now available in the supplementary material files in PDF format. However, extracting this molecular information, generally from a PDF document format is a daunting task. Here we present an approach to harvest 3D molecular data from the supporting information of scientific research articles that are normally available from publisher's resources. In order to demonstrate the feasibility of extracting truly computable molecules from PDF file formats in a fast and efficient manner, we have developed a Java based application, namely ChemEngine. This program recognizes textual patterns from the supplementary data and generates standard molecular structure data (bond matrix, atomic coordinates) that can be subjected to a multitude of computational processes automatically. The methodology has been demonstrated via several case studies on different formats of coordinates data stored in supplementary information files, wherein ChemEngine selectively harvested the atomic coordinates and interpreted them as molecules with high accuracy. The reusability of extracted molecular coordinate data was demonstrated by computing Single Point Energies that were in close agreement with the original computed data provided with the articles. It is envisaged that the methodology will enable large scale conversion of molecular information from supplementary files available in the PDF format into a collection of ready- to- compute molecular data to create an automated workflow for advanced computational processes. Software along with source codes and instructions available at https://sourceforge.net/projects/chemengine/files/?source=navbar.Graphical abstract.

  10. Lightning NOx emissions over the USA constrained by TES ozone observations and the GEOS-Chem model

    NASA Astrophysics Data System (ADS)

    Jourdain, L.; Kulawik, S. S.; Worden, H. M.; Pickering, K. E.; Worden, J.; Thompson, A. M.

    2010-01-01

    Improved estimates of NOx from lightning sources are required to understand tropospheric NOx and ozone distributions, the oxidising capacity of the troposphere and corresponding feedbacks between chemistry and climate change. In this paper, we report new satellite ozone observations from the Tropospheric Emission Spectrometer (TES) instrument that can be used to test and constrain the parameterization of the lightning source of NOx in global models. Using the National Lightning Detection (NLDN) and the Long Range Lightning Detection Network (LRLDN) data as well as the HYPSLIT transport and dispersion model, we show that TES provides direct observations of ozone enhanced layers downwind of convective events over the USA in July 2006. We find that the GEOS-Chem global chemistry-transport model with a parameterization based on cloud top height, scaled regionally and monthly to OTD/LIS (Optical Transient Detector/Lightning Imaging Sensor) climatology, captures the ozone enhancements seen by TES. We show that the model's ability to reproduce the location of the enhancements is due to the fact that this model reproduces the pattern of the convective events occurrence on a daily basis during the summer of 2006 over the USA, even though it does not well represent the relative distribution of lightning intensities. However, this model with a value of 6 Tg N/yr for the lightning source (i.e.: with a mean production of 260 moles NO/Flash over the USA in summer) underestimates the intensities of the ozone enhancements seen by TES. By imposing a production of 520 moles NO/Flash for lightning occurring in midlatitudes, which better agrees with the values proposed by the most recent studies, we decrease the bias between TES and GEOS-Chem ozone over the USA in July 2006 by 40%. However, our conclusion on the strength of the lightning source of NOx is limited by the fact that the contribution from the stratosphere is underestimated in the GEOS-Chem simulations.

  11. Exploration of Mars with the ChemCam LIBS Instrument and the Curiosity Rover

    NASA Technical Reports Server (NTRS)

    Newsom, Horton E.

    2016-01-01

    The Mars Science Laboratory (MSL) Curiosity rover landed on Mars in August 2012, and has been exploring the planet ever since. Dr. Horton E. Newsom will discuss the MSL's design and main goal, which is to characterize past environments that may have been conducive to the evolution and sustainability of life. He will also discuss Curiosity's science payload, and remote sensing, analytical capabilities, and direct discoveries of the Chemistry & Camera (ChemCam) instrument, which is the first Laser Induced Breakdown Spectrometer (LIBS) to operate on another planetary surface and determine the chemistry of the rocks and soils.

  12. Comparison of the Active Bagnold Dune Field with Other Aeolian Deposits Observed at Gale using ChemCam Data.

    NASA Astrophysics Data System (ADS)

    Cousin, A.; Dehouck, E.; Meslin, P. Y.; Williams, A. J.; Stein, N.; Gasnault, O.; Bridges, N.; Ehlmann, B. L.; Schröder, S.; Payre, V.; Rapin, W.; Pinet, P. C.; Sautter, V.; Lanza, N.; Lasue, J.; Maurice, S.; Wiens, R. C.

    2017-12-01

    The Curiosity rover at Gale crater, Mars, had the opportunity to investigate an active dune field called Bagnold Dunes for the first time on another planet. The objectives of this campaign were threefold: Understand the present-day aeolian processes on Mars by investigating the grain size of the particles and their dynamics; Understand the past aeolian processes by looking at the morphology and texture of the dunes; and Investigate the source of the dunes material by measuring their chemistry and mineralogy. The ChemCam instrument acquired a large data volume during this campaign: 18 targets on barchan dunes, 15 targets on a linear dune and then 3 targets on a mega-ripple. In this study, we compare the Bagnold Dunes data to those acquired on soil patches (Aeolis Palus soils) along the traverse corresponding to 60 targets. We have observed that the major oxide composition of the dunes is similar to that of Aeolis Palus soils, with the exception of the FeO and MnO contents that are slightly more elevated in the dunes. Moreover, the material from the dunes and more particularly the coarser particles ( 200 microns) are depleted in volatiles (mostly H) compared to the Aeolis Palus soils. The grain size analyses show that the dunes are depleted in fine-grained particles (<100 microns) compared to Aeolis Palus soils. The leading hypothesis to explain this depletion in volatiles and fine-grained particles is that the dunes, being active, have undergone physical sorting and therefore have lost their finest particles that seem to be the carrier of the volatiles (amorphous component and dust). Moreover, the dunes seem to be enriched in mafic minerals compared to the Aeolis Palus soils, as also shown by the CheMin and APXS instruments. However, thanks to the small footprint of ChemCam, we have shown that the coarsest particles were even more enriched in mafic minerals than the finer ones, in agreement with multispectral ChemCam passive and Mastcam observations. Therefore, the

  13. Accuracy Quantification of the Loci-CHEM Code for Chamber Wall Heat Transfer in a GO2/GH2 Single Element Model Problem

    NASA Technical Reports Server (NTRS)

    West, Jeff; Westra, Doug; Lin, Jeff; Tucker, Kevin

    2006-01-01

    All solutions with Loci-CHEM achieved demonstrated steady state and mesh convergence. Preconditioning had no effect on solution accuracy and typically yields a 3-5times solution speed-up. The SST turbulence model has superior performance, relative to the data in the head end region, for the rise rate and peak heat flux. It was slightly worse than the others in the downstream region where all over-predicted the data by 30-100%.There was systematic mesh refinement in the unstructured volume and structured boundary layer areas produced only minor solution differences. Mesh convergence was achieved. Overall, Loci-CHEM satisfactorily predicts heat flux rise rate and peak heat flux and significantly over predicts the downstream heat flux.

  14. Evaluating the Effectiveness of the Open-Access ChemWiki Resource as a Replacement for Traditional General Chemistry Textbooks

    ERIC Educational Resources Information Center

    Allen, Gregory; Guzman-Alvarez, Alberto; Smith, Amy; Gamage, Alan; Molinaro, Marco; Larsen, Delmar S.

    2015-01-01

    Open educational resources (OERs) provide a potential alternative to costly textbooks and can allow content to be edited and adapted to a variety of classroom environments. At the University of California, Davis, the OER "ChemWiki" project, as part of the greater STEMWiki Hyperlibrary, was developed to supplant traditional post-secondary…

  15. Trace Gases and Aerosols Simulated Over the Indian Domain: Evaluation of the Model Wrf-Chem

    NASA Astrophysics Data System (ADS)

    Michael, M.; Yadav, A.; Tripathi, S. N.; Venkataraman, C.; Kanawade, V. P.

    2012-12-01

    As the anthropogenic emissions from the Asian countries contribute substantially to the global aerosol loading, the study of the distribution of trace gases and aerosols over this region has received increasing attention in recent years. In the present work, the aerosol properties over the Indian domain during the pre-monsoon season has been addressed. The "online" meteorological and chemical transport Weather Research and Forecasting-Chemistry (WRF-Chem) model has been implemented over Indian subcontinent for three consecutive summers in 2008, 2009 and 2010.The initial and boundary conditions are obtained from NCAR reanalysis data. The global emission inventories (REanalysis of the TROpospheric chemical composition (RETRO) and Emissions Database for Global Atmospheric Research (EDGAR)) have been used and are projected for the period of study using the method provided in Ohara et al. (2007). The emission rates of sulfur dioxide, black carbon, organic carbon and PM2.5 available in the global inventory are replaced with the high resolution emission inventory developed over India for the present study. The model simulates meteorological parameters, trace gases and particulate matter. Simulated mixing ratios of trace gases (Ozone, carbon monoxide, nitrogen oxides, and SO2) are compared with ground based as well as satellite observations over India with specific focus on Indo-Gangetic Plain. Simulated aerosol optical depth are in good agreement with those observed by Aerosol Robotic Network (AERONET). The vertical profiles of extinction coefficient have been compared with the Micro Pulse Lidar Network (MPLnet) data. The simulated mass concentration of BC shows very good agreement with those observed at a few ground stations. The vertical profiles of BC have also been compared with aircraft observations carried out during summer of 2008 and 2009, resulting in good agreement. This study shows that WRF-Chem model captures many important features of the observations and

  16. Viral vectors for gene modification of plants as chem/bio sensors.

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Manginell, Monica; Harper, Jason C.; Arango, Dulce C.

    2006-11-01

    Chemical or biological sensors that are specific, sensitive, and robust allowing intelligence gathering for verification of nuclear non-proliferation treaty compliance and detouring production of weapons of mass destruction are sorely needed. Although much progress has been made in the area of biosensors, improvements in sensor lifetime, robustness, and device packaging are required before these devices become widely used. Current chemical and biological detection and identification techniques require less-than-covert sample collection followed by transport to a laboratory for analysis. In addition to being expensive and time consuming, results can often be inconclusive due to compromised sample integrity during collection and transport.more » We report here a demonstration of a plant based sensor technology which utilizes mature and seedling plants as chemical sensors. One can envision genetically modifying native plants at a site of interest that can report the presence of specific toxins or chemicals. In this one year project we used a developed inducible expression system to show the feasibility of plant sensors. The vector was designed as a safe, non-infectious vector which could be used to invade, replicate, and introduce foreign genes into mature host plants that then allow the plant to sense chem/bio agents. The genes introduced through the vector included a reporter gene that encodes for green fluorescent protein (GFP) and a gene that encodes for a mammalian receptor that recognizes a chemical agent. Specifically, GFP was induced by the presence of 17-{beta}-Estradiol (estrogen). Detection of fluorescence indicated the presence of the target chemical agent. Since the sensor is a plant, costly device packaging development or manufacturing of the sensor were not required. Additionally, the biological recognition and reporting elements are maintained in a living, natural environment and therefore do not suffer from lifetime disadvantages typical of most

  17. Comparative safety testing of genetically modified foods in a 90-day rat feeding study design allowing the distinction between primary and secondary effects of the new genetic event.

    PubMed

    Knudsen, Ib; Poulsen, Morten

    2007-10-01

    This article discusses the wider experiences regarding the usefulness of the 90-day rat feeding study for the testing of whole foods from genetically modified (GM) plant based on data from a recent EU-project [Poulsen, M., Schrøder, M., Wilcks, A., Kroghsbo, S., Lindecrona, R.H., Miller, A., Frenzel, T., Danier, J., Rychlik, M., Shu, Q., Emami, K., Taylor, M., Gatehouse, A., Engel, K.-H., Knudsen, I., 2007a. Safety testing of GM-rice expressing PHA-E lectin using a new animal test design. Food Chem. Toxicol. 45, 364-377; Poulsen, M., Kroghsbo, S., Schrøder, M., Wilcks, A., Jacobsen, H., Miller, A., Frenzel, T., Danier, J., Rychlik, M., Shu, Q., Emami, K., Sudhakar, D., Gatehouse, A., Engel, K.-H., Knudsen, I., 2007b. A 90-day safety in Wistar rats fed genetically modified rice expressing snowdrop lectin Galanthus nivalis (GNA). Food Chem. Toxicol. 45, 350-363; Schrøder, M., Poulsen, M., Wilcks, A., Kroghsbo, S., Miller, A., Frenzel, T., Danier, J., Rychlik, M., Emami, K., Gatehouse, A., Shu, Q., Engel, K.-H., Knudsen, I., 2007. A 90-day safety study of genetically modified rice expressing Cry1Ab protein (Bacillus thuringiensis toxin) in Wistar rats. Food Chem. Toxicol. 45, 339-349]. The overall objective of the project has been to develop and validate the scientific methodology necessary for assessing the safety of foods from genetically modified plants in accordance with the present EU regulation. The safety assessment in the project is combining the results of the 90-day rat feeding study on the GM food with and without spiking with the pure novel gene product, with the knowledge about the identity of the genetic change, the compositional data of the GM food, the results from in-vitro/ex-vivo studies as well as the results from the preceding 28-day toxicity study with the novel gene product, before the hazard characterisation is concluded. The results demonstrated the ability of the 90-day rat feeding study to detect the biological/toxicological effects of the

  18. Impact of Gas-Phase Mechanisms on Weather Research Forecasting Model with Chemistry (WRF/Chem) Predictions: Mechanism Implementation and Comparative Evaluation

    EPA Science Inventory

    Gas-phase mechanisms provide important oxidant and gaseous precursors for secondary aerosol formation. Different gas-phase mechanisms may lead to different predictions of gases, aerosols, and aerosol direct and indirect effects. In this study, WRF/Chem-MADRID simulations are cond...

  19. The potassic sedimentary rocks in Gale Crater, Mars, as seen by ChemCam Onboard Curiosity

    USGS Publications Warehouse

    Le Deit, Laetitia; Mangold, Nicolas; Forni, Olivier; Cousin, Agnes; Lasue, Jeremie; Schröder, Susanne; Wiens, Roger C.; Sumner, Dawn Y.; Fabre, Cecile; Stack, Katherine M.; Anderson, Ryan; Blaney, Diana L.; Clegg, Samuel M.; Dromart, Gilles; Fisk, Martin; Gasnault, Olivier; Grotzinger, John P.; Gupta, Sanjeev; Lanza, Nina; Le Mouélic, Stephane; Maurice, Sylvestre; McLennan, Scott M.; Meslin, Pierre-Yves; Nachon, Marion; Newsom, Horton E.; Payre, Valerie; Rapin, William; Rice, Melissa; Sautter, Violaine; Treiman, Alan H.

    2016-01-01

    The Mars Science Laboratory rover Curiosity encountered potassium-rich clastic sedimentary rocks at two sites in Gale Crater, the waypoints Cooperstown and Kimberley. These rocks include several distinct meters thick sedimentary outcrops ranging from fine sandstone to conglomerate, interpreted to record an ancient fluvial or fluvio-deltaic depositional system. From ChemCam Laser-Induced Breakdown Spectroscopy (LIBS) chemical analyses, this suite of sedimentary rocks has an overall mean K2O abundance that is more than 5 times higher than that of the average Martian crust. The combined analysis of ChemCam data with stratigraphic and geographic locations reveals that the mean K2O abundance increases upward through the stratigraphic section. Chemical analyses across each unit can be represented as mixtures of several distinct chemical components, i.e., mineral phases, including K-bearing minerals, mafic silicates, Fe-oxides, and Fe-hydroxide/oxyhydroxides. Possible K-bearing minerals include alkali feldspar (including anorthoclase and sanidine) and K-bearing phyllosilicate such as illite. Mixtures of different source rocks, including a potassium-rich rock located on the rim and walls of Gale Crater, are the likely origin of observed chemical variations within each unit. Physical sorting may have also played a role in the enrichment in K in the Kimberley formation. The occurrence of these potassic sedimentary rocks provides additional evidence for the chemical diversity of the crust exposed at Gale Crater.

  20. ChemHTPS - A virtual high-throughput screening program suite for the chemical and materials sciences

    NASA Astrophysics Data System (ADS)

    Afzal, Mohammad Atif Faiz; Evangelista, William; Hachmann, Johannes

    The discovery of new compounds, materials, and chemical reactions with exceptional properties is the key for the grand challenges in innovation, energy and sustainability. This process can be dramatically accelerated by means of the virtual high-throughput screening (HTPS) of large-scale candidate libraries. The resulting data can further be used to study the underlying structure-property relationships and thus facilitate rational design capability. This approach has been extensively used for many years in the drug discovery community. However, the lack of openly available virtual HTPS tools is limiting the use of these techniques in various other applications such as photovoltaics, optoelectronics, and catalysis. Thus, we developed ChemHTPS, a general-purpose, comprehensive and user-friendly suite, that will allow users to efficiently perform large in silico modeling studies and high-throughput analyses in these applications. ChemHTPS also includes a massively parallel molecular library generator which offers a multitude of options to customize and restrict the scope of the enumerated chemical space and thus tailor it for the demands of specific applications. To streamline the non-combinatorial exploration of chemical space, we incorporate genetic algorithms into the framework. In addition to implementing smarter algorithms, we also focus on the ease of use, workflow, and code integration to make this technology more accessible to the community.

  1. ChemEd X Data: Exposing Students to Open Scientific Data for Higher-Order Thinking and Self-Regulated Learning

    ERIC Educational Resources Information Center

    Eklund, Brandon; Prat-Resina, Xavier

    2014-01-01

    ChemEd X Data is an open web tool that collects and curates physical and chemical data of hundreds of substances. This tool allows students to navigate, select, and graphically represent data such as boiling and melting points, enthalpies of combustion, and heat capacities for hundreds of molecules. By doing so, students can independently identify…

  2. In Situ Detection of Boron by ChemCam on Mars

    NASA Technical Reports Server (NTRS)

    Gasda, Patrick J.; Haldeman, Ethan B.; Wiens, Roger C.; Rapin, William; Bristow, Thomas F.; Bridges, John C.; Schwenzer, Susanne P.; Clark, Benton; Herkenhoff, Kenneth; Frydenvang, Jens; hide

    2017-01-01

    We report the first in situ detection of boron on Mars. Boron has been detected in Gale crater at levels less than 0.05 wt Percent B by the NASA Curiosity rover ChemCam instrument in calcium-sulfate-filled fractures, which formed in a late-stage groundwater circulating mainly in phyllosilicate-rich bedrock interpreted as lacustrine in origin. We consider two main groundwater-driven hypotheses to explain the presence of boron in the veins: leaching of borates out of bedrock or the redistribution of borate by dissolution of borate-bearing evaporite deposits. Our results suggest that an evaporation mechanism is most likely, implying that Gale groundwaters were mildly alkaline. On Earth, boron may be a necessary component for the origin of life; on Mars, its presence suggests that subsurface groundwater conditions could have supported prebiotic chemical reactions if organics were also present and provides additional support for the past habitability of Gale crater.

  3. In Situ Detection of Boron by ChemCam on Mars

    DOE PAGES

    Gasda, Patrick J.; Haldeman, Ethan Brian; Wiens, Roger Craig; ...

    2017-09-05

    Here, we report the first in situ detection of boron on Mars. Boron has been detected in Gale crater at levels <0.05 wt % B by the NASA Curiosity rover ChemCam instrument in calcium-sulfate-filled fractures, which formed in a late-stage groundwater circulating mainly in phyllosilicate-rich bedrock interpreted as lacustrine in origin. We also consider two main groundwater-driven hypotheses to explain the presence of boron in the veins: leaching of borates out of bedrock or the redistribution of borate by dissolution of borate-bearing evaporite deposits. Our results suggest that an evaporation mechanism is most likely, implying that Gale groundwaters were mildlymore » alkaline. On Earth, boron may be a necessary component for the origin of life; on Mars, its presence suggests that subsurface groundwater conditions could have supported prebiotic chemical reactions if organics were also present and provides additional support for the past habitability of Gale crater.« less

  4. In Situ Detection of Boron by ChemCam on Mars

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gasda, Patrick J.; Haldeman, Ethan Brian; Wiens, Roger Craig

    Here, we report the first in situ detection of boron on Mars. Boron has been detected in Gale crater at levels <0.05 wt % B by the NASA Curiosity rover ChemCam instrument in calcium-sulfate-filled fractures, which formed in a late-stage groundwater circulating mainly in phyllosilicate-rich bedrock interpreted as lacustrine in origin. We also consider two main groundwater-driven hypotheses to explain the presence of boron in the veins: leaching of borates out of bedrock or the redistribution of borate by dissolution of borate-bearing evaporite deposits. Our results suggest that an evaporation mechanism is most likely, implying that Gale groundwaters were mildlymore » alkaline. On Earth, boron may be a necessary component for the origin of life; on Mars, its presence suggests that subsurface groundwater conditions could have supported prebiotic chemical reactions if organics were also present and provides additional support for the past habitability of Gale crater.« less

  5. In situ detection of boron by ChemCam on Mars

    NASA Astrophysics Data System (ADS)

    Gasda, Patrick J.; Haldeman, Ethan B.; Wiens, Roger C.; Rapin, William; Bristow, Thomas F.; Bridges, John C.; Schwenzer, Susanne P.; Clark, Benton; Herkenhoff, Kenneth; Frydenvang, Jens; Lanza, Nina L.; Maurice, Sylvestre; Clegg, Samuel; Delapp, Dorothea M.; Sanford, Veronica L.; Bodine, Madeleine R.; McInroy, Rhonda

    2017-09-01

    We report the first in situ detection of boron on Mars. Boron has been detected in Gale crater at levels <0.05 wt % B by the NASA Curiosity rover ChemCam instrument in calcium-sulfate-filled fractures, which formed in a late-stage groundwater circulating mainly in phyllosilicate-rich bedrock interpreted as lacustrine in origin. We consider two main groundwater-driven hypotheses to explain the presence of boron in the veins: leaching of borates out of bedrock or the redistribution of borate by dissolution of borate-bearing evaporite deposits. Our results suggest that an evaporation mechanism is most likely, implying that Gale groundwaters were mildly alkaline. On Earth, boron may be a necessary component for the origin of life; on Mars, its presence suggests that subsurface groundwater conditions could have supported prebiotic chemical reactions if organics were also present and provides additional support for the past habitability of Gale crater.

  6. Search for organic matter at Mars with combined measurements of the SAM and ChemCam instruments onboard the Curiosity rover

    NASA Astrophysics Data System (ADS)

    Dequaire, T.; Meslin, P. Y.; Rapin, W.; Jaber, M.; Maurice, S.; Gasnault, O.; Forni, O.; Coll, P.; Szopa, C.

    2015-10-01

    Since 2012, he Curiosity rover on Mars seeks clues of habitability in Gale crater. One of these clues is the presence of organic matter. For the moment,only a few traces of organic matter was recently found with the SAM experiment. We propose here to evaluate the capabilities for the ChemCam experiment to detect organic molecules from its elemental analysis of the Mars regolith or rocks. The first results obtained in laboratory with the ChemCam spare model and different samples show that it is possible to detect organic signatures with LIBS,focusing on atomic carbon, hydrogen and nitrogen peaks,and on a C-N molecular peak when the samples areenriched in organic molecules(100-10 wt%). We currently work with Mars representative samples to determine the instrument detection limitfor organics, in order to determine if it can be used to guide Curiosity towards interesting outcrops.

  7. Comment on “On the Crooks fluctuation theorem and the Jarzynski equality” [J. Chem. Phys. 129, 091101 (2008)

    PubMed Central

    Adib, Artur B.

    2009-01-01

    It has recently been argued that a self-consistency condition involving the Jarzynski equality (JE) and the Crooks fluctuation theorem (CFT) is violated for a simple Brownian process [L. Y. Chen, J. Chem. Phys.129, 091101 (2008)]. This note adopts the definitions in the original formulation of the JE and CFT and demonstrates the contrary. PMID:19566186

  8. pH and temperature dual-sensitive liposome gel based on novel cleavable mPEG-Hz-CHEMS polymeric vaginal delivery system

    PubMed Central

    Chen, Daquan; Sun, Kaoxiang; Mu, Hongjie; Tang, Mingtan; Liang, Rongcai; Wang, Aiping; Zhou, Shasha; Sun, Haijun; Zhao, Feng; Yao, Jianwen; Liu, Wanhui

    2012-01-01

    Background In this study, a pH and temperature dual-sensitive liposome gel based on a novel cleavable hydrazone-based pH-sensitive methoxy polyethylene glycol 2000-hydrazone-cholesteryl hemisuccinate (mPEG-Hz-CHEMS) polymer was used for vaginal administration. Methods The pH-sensitive, cleavable mPEG-Hz-CHEMS was designed as a modified pH-sensitive liposome that would selectively degrade under locally acidic vaginal conditions. The novel pH-sensitive liposome was engineered to form a thermogel at body temperature and to degrade in an acidic environment. Results A dual-sensitive liposome gel with a high encapsulation efficiency of arctigenin was formed and improved the solubility of arctigenin characterized by Fourier transform infrared spectroscopy and differential scanning calorimetry. The dual-sensitive liposome gel with a sol-gel transition at body temperature was degraded in a pH-dependent manner, and was stable for a long period of time at neutral and basic pH, but cleavable under acidic conditions (pH 5.0). Arctigenin encapsulated in a dual-sensitive liposome gel was more stable and less toxic than arctigenin loaded into pH-sensitive liposomes. In vitro drug release results indicated that dual-sensitive liposome gels showed constant release of arctigenin over 3 days, but showed sustained release of arctigenin in buffers at pH 7.4 and pH 9.0. Conclusion This research has shed some light on a pH and temperature dual-sensitive liposome gel using a cleavable mPEG-Hz-CHEMS polymer for vaginal delivery. PMID:22679372

  9. Rotational Analysis of FTIR Spectra from Cigarette Smoke: An Application of Chem Spec II Software in the Undergraduate Laboratory

    ERIC Educational Resources Information Center

    Ford, Alan R.; Burns, William A.; Reeve, Scott W.

    2004-01-01

    A version of the classic gas phase infrared experiment was developed for students at Arkansas State University based on the shortcomings of the rotationally resolved infrared experiment. Chem Spec II is a noncommercial Windows-based software package developed to aid in the potentially complicated problem of assigning quantum numbers to observed…

  10. Closure on the single scattering albedo in the WRF-Chem framework using data from the MILAGRO campaign

    NASA Astrophysics Data System (ADS)

    Barnard, J. C.; Fast, J. D.; Paredes-Miranda, G.; Arnott, W. P.

    2009-02-01

    Data from the MILAGRO field campaign, which took place in the Mexico City Metropolitan Area (MCMA) during March 2006, is used to perform a closure experiment between aerosol chemical properties and aerosol optical properties. Measured aerosol chemical properties, obtained from the MILAGRO T1 site, are fed to two different "chemical to optical properties" modules. One module uses a sectional approach and is identical to that used in the WRF-Chem model, while the other is based on a modal approach. This modal code is employed as an independent check on the WRF-Chem module. Both modules compute aerosol optical properties and, in particular, the single-scattering albedo, ϖ0, as a function of time. The single-scattering albedos are compared to independent measurements obtained from a photoacoustic spectrometer (PAS). Because chemical measurements of the aerosol coarse mode were not available, and the inlet of the PAS could not ingest aerosols larger than about 2 to 3 μm, we focus here on the fine-mode ϖ0. At 870 nm, the wavelength of the PAS measurements, the agreement between the computed (modal and WRF-Chem) and observed fine-mode ϖ0, averaged over the course of the campaign, is reasonably good. The observed ϖ0 value is 0.77, while for both modules, the calculated value was 0.75 resulting in a difference of 0.02 between observations and both computational approaches. This difference is less than the uncertainty of the observed ϖ0 values (6%, or 0.05), and therefore "closure" is achieved, at least for mean values. After adjusting some properties of black carbon absorption and mass concentration within plausible uncertainty limits, the two modules simulate well the diurnal variation of ϖ0, and the absorption coefficient, Babs, but are less successful in calculating the variation of the scattering coefficient, Bscat. This difficulty is probably caused by the presence of larger particles during the day when windblown dust is ubiquitous; this dust

  11. ChemTrove: enabling a generic ELN to support chemistry through the use of transferable plug-ins and online data sources.

    PubMed

    Day, Aileen E; Coles, Simon J; Bird, Colin L; Frey, Jeremy G; Whitby, Richard J; Tkachenko, Valery E; Williams, Antony J

    2015-03-23

    In designing an Electronic Lab Notebook (ELN), there is a balance to be struck between keeping it as general and multidisciplinary as possible for simplicity of use and maintenance and introducing more domain-specific functionality to increase its appeal to target research areas. Here, we describe the results of a collaboration between the Royal Society of Chemistry (RSC) and the University of Southampton, guided by the aims of the Dial-a-Molecule Grand Challenge, intended to achieve the best of both worlds and augment a discipline-agnostic ELN, LabTrove, with chemistry-specific functionality and using data provided by the ChemSpider platform. This has been done using plug-in technology to ensure maximum transferability with minimal effort of the chemistry functionality to other ELNs and equally other subject-specific functionality to LabTrove. The resulting product, ChemTrove, has undergone a usability trial by selected academics, and the resulting feedback will guide the future development of the underlying ELN technology.

  12. Aerosol Radiative Forcing over North India during Pre-Monsoon Season using WRF-Chem

    NASA Astrophysics Data System (ADS)

    Misra, A.; Kumar, K.; Michael, M.; Tripathi, S. N.

    2013-12-01

    Study of aerosols is important for a fair understanding of the Earth climate system. This requires knowledge of the physical, chemical, optical, and morphological properties of aerosols. Aerosol radiative forcing provides information on the effect of aerosols on the Earth radiation budget. Radiative forcing estimates using model data provide an opportunity to examine the contribution of individual aerosol species to overall radiative forcing. We have used Weather Research and Forecast with Online Chemistry (WRF-Chem) derived aerosol concentration data to compute aerosol radiative forcing over north India during pre-monsoon season of 2008, 2009, and 2010. WRF-Chem derived mass concentrations are converted to number concentrations using standard procedure. Optical Properties of Aerosol and Cloud (OPAC) software package is used to compute extinction and scattering coefficients, and asymmetry parameter. Computations are performed at different altitudes and the obtained values are integrated to get the column optical properties. Santa Barbara Discrete Ordinate Radiative Transfer (SBDART) model is used to calculate the radiative forcing at surface and top-of-atmosphere. Higher values of aerosol radiative forcing are observed over desert region in western Indian state of Rajasthan, and Punjab of Pakistan. Contribution of individual aerosol species to atmospheric radiative forcing is also assessed. Dust radiative forcing is high over western India. Radiative forcing due to BC and water-soluble (WASO) aerosols are higher over north-west Indian states of Punjab and Haryana, and the Indo-Gangetic Basin. A pool of high WASO optical depth and radiative forcing is observed over the Indo-Bangladesh border. The findings of aerosol optical depth and radiative forcing are consistent with the geography and prevailing aerosol climatology of various regions. Heating rate profiles due to total aerosols and only due to BC have been evaluated at selected stations in north India. They show

  13. Simulations of the Holuhraun eruption 2014 with WRF-Chem and evaluation with satellite and ground based SO2 measurements

    NASA Astrophysics Data System (ADS)

    Hirtl, Marcus; Arnold-Arias, Delia; Flandorfer, Claudia; Maurer, Christian; Mantovani, Simone; Natali, Stefano

    2016-04-01

    Volcanic eruptions, with gas or/and particle emissions, directly influence our environment, with special significance when they either occur near inhabited regions or are transported towards them. In addition to the well-known affectation of air traffic, with large economic impacts, the ground touching plumes can lead directly to an influence of soil, water and even to a decrease of air quality. The eruption of Holuhraun in August 2014 in central Iceland is the country's largest lava and gas eruption since the Lakagígar eruption in 1783. Nevertheless, very little volcanic ash was produced. The main atmospheric threat from this event was the SO2 pollution that frequently violated the Icelandic National Air Quality Standards in many population centers. However, the SO2 affectation was not limited to Iceland but extended to mainland Europe. The on-line coupled model WRF-Chem is used to simulate the dispersion of SO2 for this event that affected the central European regions. The volcanic emissions are considered in addition to the anthropogenic and biogenic ground sources at European scale. A modified version of WRF-Chem version 4.1 is used in order to use time depending injection heights and mass fluxes which were obtained from in situ observations. WRF-Chem uses complex gas- (RADM2) and aerosol- (MADE-SORGAM) chemistry and is operated on a European domain (12 km resolution), and a nested grid covering the Alpine region (4 km resolution). The study is showing the evaluation of the model simulations with satellite and ground based measurement data of SO2. The analysis is conducted on a data management platform, which is currently developed in the frame of the ESA-funded project TAMP "Technology and Atmospheric Mission Platform": it provides comprehensive functionalities to visualize and numerically compare data from different sources (model, satellite and ground-measurements).

  14. ChemCam results from the Shaler outcrop in Gale crater, Mars

    USGS Publications Warehouse

    Anderson, Ryan B.; Bridges, J.C.; Williams, A.; Edgar, L.; Ollila, A.; Williams, J.; Nachon, Marion; Mangold, N.; Fisk, M.; Schieber, J.; Gupta, S.; Dromart, G.; Wiens, R.; Le Mouélic, Stéphane; Forni, O.; Lanza, N.; Mezzacappa, Alissa; Sautter, V.; Blaney, D.; Clark, B.; Clegg, S.; Gasnault, O.; Lasue, J.; Léveillé, Richard; Lewin, E.; Lewis, K.W.; Maurice, S.; Newsom, H.; Schwenzer, S.P.; Vaniman, D.

    2015-01-01

    The ChemCam campaign at the fluvial sedimentary outcrop “Shaler” resulted in observations of 28 non-soil targets, 26 of which included active laser induced breakdown spectroscopy (LIBS), and all of which included Remote Micro-Imager (RMI) images. The Shaler outcrop can be divided into seven facies based on grain size, texture, color, resistance to erosion, and sedimentary structures. The ChemCam observations cover Facies 3 through 7. For all targets, the majority of the grains were below the limit of the RMI resolution, but many targets had a portion of resolvable grains coarser than ∼0.5 mm. The Shaler facies show significant scatter in LIBS spectra and compositions from point to point, but several key compositional trends are apparent, most notably in the average K2O content of the observed facies. Facies 3 is lower in K2O than the other facies and is similar in composition to the “snake,” a clastic dike that occurs lower in the Yellowknife Bay stratigraphic section. Facies 7 is enriched in K2O relative to the other facies and shows some compositional and textural similarities to float rocks near Yellowknife Bay. The remaining facies (4, 5, and 6) are similar in composition to the Sheepbed and Gillespie Lake members, although the Shaler facies have slightly elevated K2O and FeOT. Several analysis points within Shaler suggest the presence of feldspars, though these points have excess FeOT which suggests the presence of Fe oxide cement or inclusions. The majority of LIBS analyses have compositions which indicate that they are mixtures of pyroxene and feldspar. The Shaler feldspathic compositions are more alkaline than typical feldspars from shergottites, suggesting an alkaline basaltic source region, particularly for the K2O-enriched Facies 7. Apart from possible iron-oxide cement, there is little evidence for chemical alteration at Shaler, although calcium-sulfate veins comparable to those observed lower in the stratigraphic section are present. The

  15. WRF-Chem Simulations of Lightning-NOx Production and Transport in Oklahoma and Colorado Thunderstorms Observed During DC3

    NASA Technical Reports Server (NTRS)

    Cummings, Kristin A.; Pickering, Kenneth E.; Barth, M.; Bela, M.; Li, Y.; Allen, D.; Bruning, E.; MacGorman, D.; Rutledge, S.; Basarab, B.; hide

    2016-01-01

    The focus of this analysis is on lightning-generated nitrogen oxides (LNOx) and their distribution for two thunderstorms observed during the Deep Convective Clouds and Chemistry (DC3) field campaign in May-June 2012. The Weather Research and Forecasting Chemistry (WRF-Chem) model is used to perform cloud-resolved simulations for the May 29-30 Oklahoma severe convection, which contained one supercell, and the June 6-7 Colorado squall line. Aircraft and ground-based observations (e.g., trace gases, lightning and radar) collected during DC3 are used in comparisons against the model-simulated lightning flashes generated by the flash rate parameterization schemes (FRPSs) incorporated into the model, as well as the model-simulated LNOx predicted in the anvil outflow. Newly generated FRPSs based on DC3 radar observations and Lightning Mapping Array data are implemented in the model, along with previously developed schemes from the literature. The results of these analyses will also be compared between storms to investigate which FRPSs were most appropriate for the two types of convection and to examine the variation in the LNOx production. The simulated LNOx results from WRF-Chem will also be compared against other previously studied mid-latitude thunderstorms.

  16. Comparison of Mixed Layer Heights from Airborne High Spectral Resolution Lidar, Ground-based Measurements, and the WRP-Chem Model during CalNex and CARES

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Scarino, Amy Jo; Obland, Michael; Fast, Jerome D.

    2014-06-05

    The California Research at the Nexus of Air Quality and Climate Change (CalNex) and Carbonaceous Aerosol and Radiative Effects Study (CARES) field campaigns during May and June 2010 provided a data set appropriate for studying characteristics of the planetary boundary layer (PBL). The NASA Langley Research Center (LaRC) airborne High Spectral Resolution Lidar (HSRL) was deployed to California onboard the NASA LaRC B-200 aircraft to aid incharacterizing aerosol properties during these two field campaigns. Measurements of aerosol extinction (532 nm), backscatter (532 and 1064 nm), and depolarization (532 and 1064 nm) profiles during 31 flights, many in coordination with othermore » research aircraft and ground sites, constitute a diverse data set for use in characterizing the spatial and temporal distribution of aerosols, as well as the depth and variability of the daytime mixed layer (ML), which is a subset within the PBL. This work illustrates the temporal and spatial variability of the ML in the vicinity of Los Angeles and Sacramento, CA. ML heights derived from HSRL measurements are compared to PBL heights derived from radiosonde profiles, ML heights measured from ceilometers, and simulated PBL heights from the Weather Research and Forecasting Chemistry (WRF-Chem) community model. Comparisons between the HSRL ML heights and the radiosonde profiles in Sacramento result in a correlation coefficient value (R) of 0.93 (root7 mean-square (RMS) difference of 157 m and bias difference (HSRL radiosonde) of 5 m). HSRL ML heights compare well with those from the ceilometer in the LA Basin with an R of 0.89 (RMS difference of 108 m and bias difference (HSRL Ceilometer) of -9.7 m) for distances of up to 30 km between the B-200 flight track and the ceilometer site. Simulated PBL heights from WRF-Chem were compared with those obtained from all flights for each campaign, producing an R of 0.58 (RMS difference of 604 m and a bias difference (WRF-Chem HSRL) of -157 m) for Cal

  17. Comparison of mixed layer heights from airborne high spectral resolution lidar, ground-based measurements, and the WRF-Chem model during CalNex and CARES

    NASA Astrophysics Data System (ADS)

    Scarino, A. J.; Obland, M. D.; Fast, J. D.; Burton, S. P.; Ferrare, R. A.; Hostetler, C. A.; Berg, L. K.; Lefer, B.; Haman, C.; Hair, J. W.; Rogers, R. R.; Butler, C.; Cook, A. L.; Harper, D. B.

    2013-05-01

    The California Research at the Nexus of Air Quality and Climate Change (CalNex) and Carbonaceous Aerosol and Radiative Effects Study (CARES) field campaigns during May and June 2010 provided a data set appropriate for studying characteristics of the planetary boundary layer (PBL). The NASA Langley Research Center (LaRC) airborne High Spectral Resolution Lidar (HSRL) was deployed to California onboard the NASA LaRC B-200 aircraft to aid in characterizing aerosol properties during these two field campaigns. Measurements of aerosol extinction (532 nm), backscatter (532 and 1064 nm), and depolarization (532 and 1064 nm) profiles during 31 flights, many in coordination with other research aircraft and ground sites, constitute a diverse data set for use in characterizing the spatial and temporal distribution of aerosols, as well as the depth and variability of the daytime mixed layer (ML), which is a subset within the PBL. This work illustrates the temporal and spatial variability of the ML in the vicinity of Los Angeles and Sacramento, CA. ML heights derived from HSRL measurements are compared to PBL heights derived from radiosonde profiles, ML heights measured from ceilometers, and simulated PBL heights from the Weather Research and Forecasting Chemistry (WRF-Chem) community model. Comparisons between the HSRL ML heights and the radiosonde profiles in Sacramento result in a correlation coefficient value (R) of 0.93 (root-mean-square (RMS) difference of 157 m and bias difference (HSRL - radiosonde) of 57 m). HSRL ML heights compare well with those from the ceilometer in the LA Basin with an R of 0.89 (RMS difference of 108 m and bias difference (HSRL - Ceilometer) of -9.7 m) for distances of up to 30 km between the B-200 flight track and the ceilometer site. Simulated PBL heights from WRF-Chem were compared with those obtained from all flights for each campaign, producing an R of 0.58 (RMS difference of 604 m and a bias difference (WRF-Chem - HSRL) of -157 m) for Cal

  18. Chemistry of diagenetic features analyzed by ChemCam at Pahrump Hills, Gale crater, Mars

    USGS Publications Warehouse

    Nachon, Marion; Mangold, Nicolas; Forni, Olivier; Kah, Linda C.; Cousin, Agnes; Wiens, Roger C.; Anderson, Ryan; Blaney, Diana L.; Blank, Jen G.; Calef, Fred J.; Clegg, Samuel M.; Fabre, Cecile; Fisk, Martin R.; Gasnault, Olivier; Grotzinger, John P.; Kronyak, Rachel; Lanza, Nina L.; Lasue, Jeremie; Le Deit, Laetitia; Le Mouelic, Stephane; Maurice, Sylvestre; Meslin, Pierre-Yves; Oehler, D. Z.; Payre, Valerie; Rapin, William; Schroder, Susanne; Stack, Katherine M.; Sumner, Dawn

    2017-01-01

    The Curiosity rover's campaign at Pahrump Hills provides the first analyses of lower Mount Sharp strata. Here we report ChemCam elemental composition of a diverse assemblage of post-depositional features embedded in, or cross-cutting, the host rock. ChemCam results demonstrate their compositional diversity, especially compared to the surrounding host rock: (i) Dendritic aggregates and relief enhanced features, characterized by a magnesium enhancement and sulfur detection, and interpreted as Mg-sulfates; (ii) A localized observation that displays iron enrichment associated with sulfur, interpreted as Fe-sulfate; (iii) Dark raised ridges with varying Mg- and Ca-enriched compositions compared to host rock; (iv) Several dark-toned veins with calcium enhancement associated with fluorine detection, interpreted as fluorite veins. (v) Light-toned veins with enhanced calcium associated with sulfur detection, and interpreted as Ca-sulfates. The diversity of the Pahrump Hills diagenetic assemblage suggests a complex post-depositional history for fine-grained sediments for which the origin has been interpreted as fluvial and lacustrine. Assessment of the spatial and relative temporal distribution of these features shows that the Mg-sulfate features are predominant in the lower part of the section, suggesting local modification of the sediments by early diagenetic fluids. In contrast, light-toned Ca-sulfate veins occur in the whole section and cross-cut all other features. A relatively late stage shift in geochemical conditions could explain this observation. The Pahrump Hills diagenetic features have no equivalent compared to targets analyzed in other locations at Gale crater. Only the light-toned Ca-sulfate veins are present elsewhere, along Curiosity's path, suggesting they formed through a common late-stage process that occurred at over a broad area.

  19. Feasibility of Integration of Selected Aspects of (CBA) Chemistry, (CHEMS) Chemistry and (PSSC) Physics into a Two Year Physical Science Sequence.

    ERIC Educational Resources Information Center

    Fiasca, Michael Aldo

    Compared, for selected outcomes, were integrated chemistry-physics courses with chemistry and physics courses taught separately. Three classes studying integrated Physical Science Study Committee (PSSC)-Chemical Bond Approach (CBA), and three classes studying integrated Physical Science Study Committee-Chemical Education Materials Study (CHEMS)…

  20. The ChemCam Instrument Suite on the Mars Science Laboratory (MSL) Rover: Science Objectives and Mast Unit Description

    USGS Publications Warehouse

    Maurice, S.; Wiens, R.C.; Saccoccio, M.; Barraclough, B.; Gasnault, O.; Forni, O.; Mangold, N.; Baratoux, D.; Bender, S.; Berger, G.; Bernardin, J.; Berthé, M.; Bridges, N.; Blaney, D.; Bouyé, M.; Caïs, P.; Clark, B.; Clegg, S.; Cousin, A.; Cremers, D.; Cros, A.; DeFlores, L.; Derycke, C.; Dingler, B.; Dromart, G.; Dubois, B.; Dupieux, M.; Durand, E.; d'Uston, L.; Fabre, C.; Faure, B.; Gaboriaud, A.; Gharsa, T.; Herkenhoff, K.; Kan, E.; Kirkland, L.; Kouach, D.; Lacour, J.-L.; Langevin, Y.; Lasue, J.; Le Mouélic, S.; Lescure, M.; Lewin, E.; Limonadi, D.; Manhès, G.; Mauchien, P.; McKay, C.; Meslin, P.-Y.; Michel, Y.; Miller, E.; Newsom, Horton E.; Orttner, G.; Paillet, A.; Parès, L.; Parot, Y.; Pérez, R.; Pinet, P.; Poitrasson, F.; Quertier, B.; Sallé, B.; Sotin, Christophe; Sautter, V.; Séran, H.; Simmonds, J.J.; Sirven, J.-B.; Stiglich, R.; Striebig, N.; Thocaven, J.-J.; Toplis, M.J.; Vaniman, D.

    2012-01-01

    ChemCam is a remote sensing instrument suite on board the "Curiosity" rover (NASA) that uses Laser-Induced Breakdown Spectroscopy (LIBS) to provide the elemental composition of soils and rocks at the surface of Mars from a distance of 1.3 to 7 m, and a telescopic imager to return high resolution context and micro-images at distances greater than 1.16 m. We describe five analytical capabilities: rock classification, quantitative composition, depth profiling, context imaging, and passive spectroscopy. They serve as a toolbox to address most of the science questions at Gale crater. ChemCam consists of a Mast-Unit (laser, telescope, camera, and electronics) and a Body-Unit (spectrometers, digital processing unit, and optical demultiplexer), which are connected by an optical fiber and an electrical interface. We then report on the development, integration, and testing of the Mast-Unit, and summarize some key characteristics of ChemCam. This confirmed that nominal or better than nominal performances were achieved for critical parameters, in particular power density (>1 GW/cm2). The analysis spot diameter varies from 350 μm at 2 m to 550 μm at 7 m distance. For remote imaging, the camera field of view is 20 mrad for 1024×1024 pixels. Field tests demonstrated that the resolution (˜90 μrad) made it possible to identify laser shots on a wide variety of images. This is sufficient for visualizing laser shot pits and textures of rocks and soils. An auto-exposure capability optimizes the dynamical range of the images. Dedicated hardware and software focus the telescope, with precision that is appropriate for the LIBS and imaging depths-of-field. The light emitted by the plasma is collected and sent to the Body-Unit via a 6 m optical fiber. The companion to this paper (Wiens et al. this issue) reports on the development of the Body-Unit, on the analysis of the emitted light, and on the good match between instrument performance and science specifications.

  1. Identifying "known unknowns": A comparison between ChemSpider and the US EPA's CompTox Dashboard (ACS Spring National meeting) 1 of 7

    EPA Science Inventory

    Non-targeted analysis (NTA) workflows in high-resolution mass spectrometry require mechanisms for compound identification. One strategy for tentative identification is the use of online chemical databases such as ChemSpider. Databases like this use molecular formulae and monois...

  2. A statistical downscaling approach for roadside NO2 concentrations: Application to a WRF-Chem study for Berlin

    NASA Astrophysics Data System (ADS)

    Kuik, Friderike; Lauer, Axel; von Schneidemesser, Erika; Butler, Tim

    2017-04-01

    Many European cities continue to struggle with meeting the European air quality limits for NO2. In Berlin, Germany, most of the exceedances in NO2 recorded at monitoring sites near busy roads can be largely attributed to emissions from traffic. In order to assess the impact of changes in traffic emissions on air quality at policy relevant scales, we combine the regional atmosphere-chemistry transport model WRF-Chem at a resolution of 1kmx1km with a statistical downscaling approach. Here, we build on the recently published study evaluating the performance of a WRF-Chem setup in representing observed urban background NO2 concentrations from Kuik et al. (2016) and extend this setup by developing and testing an approach to statistically downscale simulated urban background NO2 concentrations to street level. The approach uses a multilinear regression model to relate roadside NO2 concentrations observed with the municipal monitoring network with observed NO2 concentrations at urban background sites and observed traffic counts. For this, the urban background NO2 concentrations are decomposed into a long term, a synoptic and a diurnal component using the Kolmogorov-Zurbenko filtering method. We estimate the coefficients of the regression model for five different roadside stations in Berlin representing different street types. In a next step we combine the coefficients with simulated urban background concentrations and observed traffic counts, in order to estimate roadside NO2 concentrations based on the results obtained with WRF-Chem at the five selected stations. In a third step, we extrapolate the NO2 concentrations to all major roads in Berlin. The latter is based on available data for Berlin of daily mean traffic counts, diurnal and weekly cycles of traffic as well as simulated urban background NO2 concentrations. We evaluate the NO2 concentrations estimated with this method at street level for Berlin with additional observational data from stationary measurements and

  3. A Study on the Bionomics of Anopheles darlingi Root (Diptera: Culicidae) in Belize, Central America

    DTIC Science & Technology

    2004-03-01

    Mosquitoes of medical importance. U.S. Dep. Agric. Agric. Handb. 152. Forattini, O.P. 1962. Entomologia medica vol. I. Faculdade de Higiene e Saude Publica...meridional do Brasil. Rev. Saude Publ., S. Paulo. 21: 291-304. Forattini, O.P. 1962. Entomologia medica vol. I. Faculdade de Higiene e Saude...152. Forattini, O.P. 1962. Entomologia medica vol. I. Faculdade de Higiene e Saude Publica, Sao Paulo, Brazil. 662 pp. Grieco, J.P. 2001. The

  4. Note: Derivation of two-photon circular dichroism—Addendum to “Two-photon circular dichroism” [J. Chem. Phys. 62, 1006 (1975)

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Friese, Daniel H., E-mail: daniel.h.friese@uit.no

    2015-09-07

    This addendum shows the detailed derivation of the fundamental equations for two-photon circular dichroism which are given in a very condensed form in the original publication [I. Tinoco, J. Chem. Phys. 62, 1006 (1975)]. In addition, some minor errors are corrected and some of the derivations in the original publication are commented.

  5. Errors and improvements in the use of archived meteorological data for chemical transport modeling: an analysis using GEOS-Chem v11-01 driven by GEOS-5 meteorology

    NASA Astrophysics Data System (ADS)

    Yu, Karen; Keller, Christoph A.; Jacob, Daniel J.; Molod, Andrea M.; Eastham, Sebastian D.; Long, Michael S.

    2018-01-01

    Global simulations of atmospheric chemistry are commonly conducted with off-line chemical transport models (CTMs) driven by archived meteorological data from general circulation models (GCMs). The off-line approach has the advantages of simplicity and expediency, but it incurs errors due to temporal averaging in the meteorological archive and the inability to reproduce the GCM transport algorithms exactly. The CTM simulation is also often conducted at coarser grid resolution than the parent GCM. Here we investigate this cascade of CTM errors by using 222Rn-210Pb-7Be chemical tracer simulations off-line in the GEOS-Chem CTM at rectilinear 0.25° × 0.3125° (≈ 25 km) and 2° × 2.5° (≈ 200 km) resolutions and online in the parent GEOS-5 GCM at cubed-sphere c360 (≈ 25 km) and c48 (≈ 200 km) horizontal resolutions. The c360 GEOS-5 GCM meteorological archive, updated every 3 h and remapped to 0.25° × 0.3125°, is the standard operational product generated by the NASA Global Modeling and Assimilation Office (GMAO) and used as input by GEOS-Chem. We find that the GEOS-Chem 222Rn simulation at native 0.25° × 0.3125° resolution is affected by vertical transport errors of up to 20 % relative to the GEOS-5 c360 online simulation, in part due to loss of transient organized vertical motions in the GCM (resolved convection) that are temporally averaged out in the 3 h meteorological archive. There is also significant error caused by operational remapping of the meteorological archive from a cubed-sphere to a rectilinear grid. Decreasing the GEOS-Chem resolution from 0.25° × 0.3125° to 2° × 2.5° induces further weakening of vertical transport as transient vertical motions are averaged out spatially and temporally. The resulting 222Rn concentrations simulated by the coarse-resolution GEOS-Chem are overestimated by up to 40 % in surface air relative to the online c360 simulations and underestimated by up to 40 % in the upper

  6. Improvements to the WRF-Chem 3.5.1 model for quasi-hemispheric simulations of aerosols and ozone in the Arctic

    NASA Astrophysics Data System (ADS)

    Marelle, Louis; Raut, Jean-Christophe; Law, Kathy S.; Berg, Larry K.; Fast, Jerome D.; Easter, Richard C.; Shrivastava, Manish; Thomas, Jennie L.

    2017-10-01

    In this study, the WRF-Chem regional model is updated to improve simulated short-lived pollutants (e.g., aerosols, ozone) in the Arctic. Specifically, we include in WRF-Chem 3.5.1 (with SAPRC-99 gas-phase chemistry and MOSAIC aerosols) (1) a correction to the sedimentation of aerosols, (2) dimethyl sulfide (DMS) oceanic emissions and gas-phase chemistry, (3) an improved representation of the dry deposition of trace gases over seasonal snow, and (4) an UV-albedo dependence on snow and ice cover for photolysis calculations. We also (5) correct the representation of surface temperatures over melting ice in the Noah Land Surface Model and (6) couple and further test the recent KF-CuP (Kain-Fritsch + Cumulus Potential) cumulus parameterization that includes the effect of cumulus clouds on aerosols and trace gases. The updated model is used to perform quasi-hemispheric simulations of aerosols and ozone, which are evaluated against surface measurements of black carbon (BC), sulfate, and ozone as well as airborne measurements of BC in the Arctic. The updated model shows significant improvements in terms of seasonal aerosol cycles at the surface and root mean square errors (RMSEs) for surface ozone, aerosols, and BC aloft, compared to the base version of the model and to previous large-scale evaluations of WRF-Chem in the Arctic. These improvements are mostly due to the inclusion of cumulus effects on aerosols and trace gases in KF-CuP (improved RMSE for surface BC and BC profiles, surface sulfate, and surface ozone), the improved surface temperatures over sea ice (surface ozone, BC, and sulfate), and the updated trace gas deposition and UV albedo over snow and ice (improved RMSE and correlation for surface ozone). DMS emissions and chemistry improve surface sulfate at all Arctic sites except Zeppelin, and correcting aerosol sedimentation has little influence on aerosols except in the upper troposphere.

  7. Interactions between volatile organic compounds and reactive halogen in the tropical marine atmosphere using WRF-Chem

    NASA Astrophysics Data System (ADS)

    Badia, Alba; Reeves, Claire E.; Baker, Alex; Volkamer, Rainer; von Glasow, Roland

    2016-04-01

    Halogen species (chlorine, bromine and iodine) are known to play an important role in the chemistry and oxidizing capacity of the troposphere, particularly in the marine boundary layer (MBL). Reactive halogens cause ozone (O3) destruction, change the HOx and NOX partitioning, affect the oxidation of volatile organic compounds (VOCs) and mercury, reduce the lifetime of methane, and take part in new particle formation. Numerical models predicted that reactive halogen compounds account for 30% of O3 destruction in the MBL and 5-20% globally. There are indications that the chemistry of reactive halogens and oxygenated VOCs (OVOCs) in the tropics are inter-related. Moreover, the presence of aldehydes, such as glyoxal (CHOCHO), has a potential impact on radical cycling and secondary organic aerosol (SOA) formation in the MBL and free troposphere (FT). Model calculations suggest aldehydes to be an important sink for bromine atoms and hence competition for their reaction with O3 forming BrO and so illustrating a link between the cycles of halogens and OVOCs in the marine atmosphere. The main objective of this contribution is to investigate the atmospheric chemistry in the tropical East Pacific with a focus on reactive halogens and OVOCs and their links using the latest version of the Weather Research and Forecasting (WRF) model coupled with Chemistry (WRF-Chem) and field data from the TORERO campaign. WRF-Chem is a highly flexible community model for atmospheric research where aerosol-radiation-cloud feedback processes are taken into account. Our current reaction mechanism in WRF-Chem is based on the MOZART mechanism and has been extended to include bromine, chlorine and iodine chemistry. The MOZART mechanism includes detailed gas-phase chemistry of CHOCHO formation as well as state-of-the-science pathways to form SOA. Oceanic emissions of aldehydes, including CHOCHO, and of organic halogens based on measurements from the TORERO campaign have been added into the model. Sea

  8. A non-targeted metabolomic approach to identify food markers to support discrimination between organic and conventional tomato crops.

    PubMed

    Martínez Bueno, María Jesús; Díaz-Galiano, Francisco José; Rajski, Łukasz; Cutillas, Víctor; Fernández-Alba, Amadeo R

    2018-04-20

    In the last decade, the consumption trend of organic food has increased dramatically worldwide. However, the lack of reliable chemical markers to discriminate between organic and conventional products makes this market susceptible to food fraud in products labeled as "organic". Metabolomic fingerprinting approach has been demonstrated as the best option for a full characterization of metabolome occurring in plants, since their pattern may reflect the impact of both endogenous and exogenous factors. In the present study, advanced technologies based on high performance liquid chromatography-high-resolution accurate mass spectrometry (HPLC-HRAMS) has been used for marker search in organic and conventional tomatoes grown in greenhouse under controlled agronomic conditions. The screening of unknown compounds comprised the retrospective analysis of all tomato samples throughout the studied period and data processing using databases (mzCloud, ChemSpider and PubChem). In addition, stable nitrogen isotope analysis (δ 15 N) was assessed as a possible indicator to support discrimination between both production systems using crop/fertilizer correlations. Pesticide residue analyses were also applied as a well-established way to evaluate the organic production. Finally, the evaluation by combined chemometric analysis of high-resolution accurate mass spectrometry (HRAMS) and δ 15 N data provided a robust classification model in accordance with the agricultural practices. Principal component analysis (PCA) showed a sample clustering according to farming systems and significant differences in the sample profile was observed for six bioactive components (L-tyrosyl-L-isoleucyl-L-threonyl-L-threonine, trilobatin, phloridzin, tomatine, phloretin and echinenone). Copyright © 2018 Elsevier B.V. All rights reserved.

  9. Validating the WRF-Chem model for wind energy applications using High Resolution Doppler Lidar data from a Utah 2012 field campaign

    NASA Astrophysics Data System (ADS)

    Mitchell, M. J.; Pichugina, Y. L.; Banta, R. M.

    2015-12-01

    Models are important tools for assessing potential of wind energy sites, but the accuracy of these projections has not been properly validated. In this study, High Resolution Doppler Lidar (HRDL) data obtained with high temporal and spatial resolution at heights of modern turbine rotors were compared to output from the WRF-chem model in order to help improve the performance of the model in producing accurate wind forecasts for the industry. HRDL data were collected from January 23-March 1, 2012 during the Uintah Basin Winter Ozone Study (UBWOS) field campaign. A model validation method was based on the qualitative comparison of the wind field images, time-series analysis and statistical analysis of the observed and modeled wind speed and direction, both for case studies and for the whole experiment. To compare the WRF-chem model output to the HRDL observations, the model heights and forecast times were interpolated to match the observed times and heights. Then, time-height cross-sections of the HRDL and WRF-Chem wind speed and directions were plotted to select case studies. Cross-sections of the differences between the observed and forecasted wind speed and directions were also plotted to visually analyze the model performance in different wind flow conditions. A statistical analysis includes the calculation of vertical profiles and time series of bias, correlation coefficient, root mean squared error, and coefficient of determination between two datasets. The results from this analysis reveals where and when the model typically struggles in forecasting winds at heights of modern turbine rotors so that in the future the model can be improved for the industry.

  10. Chemistry of diagenetic features analyzed by ChemCam at Pahrump Hills, Gale crater, Mars

    DOE PAGES

    Nachon, M.; Mangold, N.; Forni, O.; ...

    2017-09-01

    The Curiosity rover's campaign at Pahrump Hills provides the first analyses of lower Mount Sharp strata. We report ChemCam elemental composition of a diverse assemblage of post-depositional features embedded in, or cross-cutting, the host rock. ChemCam results demonstrate their compositional diversity, especially compared to the surrounding host rock: (i) Dendritic aggregates and relief enhanced features, characterized by a magnesium enhancement and sulfur detection, and interpreted as Mg-sulfates; (ii) A localized observation that displays iron enrichment associated with sulfur, interpreted as Fe-sulfate; (iii) Dark raised ridges with varying Mg- and Ca-enriched compositions compared to host rock; (iv) Several dark-toned veins withmore » calcium enhancement associated with fluorine detection, interpreted as fluorite veins. (v) Light-toned veins with enhanced calcium associated with sulfur detection, and interpreted as Ca-sulfates. The diversity of the Pahrump Hills diagenetic assemblage suggests a complex post-depositional history for fine-grained sediments for which the origin has been interpreted as fluvial and lacustrine. Assessment of the spatial and relative temporal distribution of these features shows that the Mg-sulfate features are predominant in the lower part of the section, suggesting local modification of the sediments by early diagenetic fluids. Conversely, light-toned Ca-sulfate veins occur in the whole section and cross-cut all other features. A relatively late stage shift in geochemical conditions could explain this observation. The Pahrump Hills diagenetic features have no equivalent compared to targets analyzed in other locations at Gale crater. Only the light-toned Ca-sulfate veins are present elsewhere, along Curiosity's path, suggesting they formed through a common late-stage process that occurred at over a broad area.« less

  11. Chemistry of diagenetic features analyzed by ChemCam at Pahrump Hills, Gale crater, Mars

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Nachon, M.; Mangold, N.; Forni, O.

    The Curiosity rover's campaign at Pahrump Hills provides the first analyses of lower Mount Sharp strata. We report ChemCam elemental composition of a diverse assemblage of post-depositional features embedded in, or cross-cutting, the host rock. ChemCam results demonstrate their compositional diversity, especially compared to the surrounding host rock: (i) Dendritic aggregates and relief enhanced features, characterized by a magnesium enhancement and sulfur detection, and interpreted as Mg-sulfates; (ii) A localized observation that displays iron enrichment associated with sulfur, interpreted as Fe-sulfate; (iii) Dark raised ridges with varying Mg- and Ca-enriched compositions compared to host rock; (iv) Several dark-toned veins withmore » calcium enhancement associated with fluorine detection, interpreted as fluorite veins. (v) Light-toned veins with enhanced calcium associated with sulfur detection, and interpreted as Ca-sulfates. The diversity of the Pahrump Hills diagenetic assemblage suggests a complex post-depositional history for fine-grained sediments for which the origin has been interpreted as fluvial and lacustrine. Assessment of the spatial and relative temporal distribution of these features shows that the Mg-sulfate features are predominant in the lower part of the section, suggesting local modification of the sediments by early diagenetic fluids. Conversely, light-toned Ca-sulfate veins occur in the whole section and cross-cut all other features. A relatively late stage shift in geochemical conditions could explain this observation. The Pahrump Hills diagenetic features have no equivalent compared to targets analyzed in other locations at Gale crater. Only the light-toned Ca-sulfate veins are present elsewhere, along Curiosity's path, suggesting they formed through a common late-stage process that occurred at over a broad area.« less

  12. Gaseous Chemistry and Aerosol Mechanism Developments for Version 3.5.1 of the Online Regional Model, WRF-Chem

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Archer-Nicholls, Scott; Lowe, Douglas; Utembe, Steve

    We have made a number of developments in the regional coupled model WRF-Chem, with the aim of making the model more suitable for prediction of atmospheric composition and of interactions between air quality and weather. We have worked on the European domain, with a particular focus on making the model suitable for the study of night time chemistry and oxidation by the nitrate radical in the UK atmosphere. A reduced form of the Common Reactive Intermediates gas-phase chemical mechanism (CRIv2-R5) has been implemented to enable more explicit simulation of VOC degradation. N2O5 heterogeneous chemistry has been added to the existingmore » sectional MOSAIC aerosol module, and coupled to both the CRIv2-R5 and existing CBM-Z gas phase scheme. Modifications have also been made to the sea-spray aerosol emission representation, allowing the inclusion of primary organic material in sea-spray aerosol. Driven by appropriate emissions, wind fields and chemical boundary conditions, implementation of the different developments is illustrated in order to demonstrate the impact that these changes have in the North-West European domain. These developments are now part of the freely available WRF-Chem distribution.« less

  13. ChemCam Passive Sky Spectroscopy at Gale Crater, Mars: Interannual Variability in Dust Aerosol Particle Size, Missing Water Vapor, and the Molecular Oxygen Problem

    NASA Astrophysics Data System (ADS)

    McConnochie, T. H.; Smith, M. D.; Wolff, M. J.; Bender, S. C.; Lemmon, M. T.; Wiens, R. C.; Maurice, S.; Gasnault, O.; Lasue, J.; Meslin, P. Y.; Harri, A. M.; Genzer, M.; Kemppinen, O.; Martinez, G.; DeFlores, L. P.; Blaney, D. L.; Johnson, J. R.; Bell, J. F., III; Trainer, M. G.; Lefèvre, F.; Atreya, S. K.; Mahaffy, P. R.; Wong, M. H.; Franz, H. B.; Guzewich, S.; Villanueva, G. L.; Khayat, A. S.

    2017-12-01

    The Mars Science Laboratory's (MSL) ChemCam spectrometer measures atmospheric aerosol properties and gas abundances by operating in passive mode and observing scattered sky light at two different elevation angles. We have previously [e. g. 1, 2] presented the methodology and results of these ChemCam Passive Sky observations. Here we will focus on three of the more surprising results that we have obtained: (1) depletion of the column water vapor at Gale Crater relative to that of the surrounding region combined with a strong enhancement of the local column water vapor relative to pre-dawn in-situ measurements, (2) an interannual change in the effective particle size of dust aerosol during the aphelion season, and (3) apparent seasonal and interannual variability in molecular oxygen that differs significantly from the expected behavior of a non-condensable trace gas and differs significantly from global climate model expectations. The ChemCam passive sky water vapor measurements are quite robust but their interpretation depends on the details of measurements as well as on the types of water vapor vertical distributions that can be produced by climate models. We have a high degree of confidence in the dust particle size changes but since aerosol results in general are subject to a variety of potential systematic effects our particle size results would benefit from confirmation by other techniques [c.f. 3]. For the ChemCam passive sky molecular oxygen results we are still working to constrain the uncertainties well enough to confirm the observed surprising behavior, motivated by similarly surprising atmospheric molecular oxygen variability observed by MSL's Sample Analysis at Mars (SAM) instrument [4]. REFERENCES: [1] McConnochie, et al. (2017), Icarus (submitted). [2] McConnochie, et al. (2017), abstract # 3201, The 6th International Workshop on the Mars Atmosphere: Granada, Spain. [3] Vicente-Retortillo et al. (2017), GRL, 44. [4] Trainer et al. (2017), 2017 AGU Fall

  14. Comment on “On the quantum theory of molecules” [J. Chem. Phys. 137, 22A544 (2012)

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sutcliffe, Brian T., E-mail: bsutclif@ulb.ac.be; Woolley, R. Guy

    2014-01-21

    In our previous paper [B. T. Sutcliffe and R. G. Woolley, J. Chem. Phys. 137, 22A544 (2012)] we argued that the Born-Oppenheimer approximation could not be based on an exact transformation of the molecular Schrödinger equation. In this Comment we suggest that the fundamental reason for the approximate nature of the Born-Oppenheimer model is the lack of a complete set of functions for the electronic space, and the need to describe the continuous spectrum using spectral projection.

  15. ChemCam Exploration of the rocks and soils of Gale Crater from “Rocknest” to “Yellow Knife Bay”

    NASA Astrophysics Data System (ADS)

    Blaney, Diana L.; Clegg, S. M.; Anderson, R.; Wiens, R.; Maurice, S.; Gasnault, O.; Barraclough, B.; Berger, G.; Bridges, J. C.; Bridges, N.; Clark, B.; Dyar, M. D.; Edgar, L.; Ehlmann, B.; Goetz, W.; Kah, L.; King, P.; Lanza, N.; Madsen, M.; LeMouelic, S.; Mangold, N.; Meslin, P. Y.; Newsom, H.; Ollila, A.; Rowland, S.; Schmidt, M.; Schröder, S.; Tokar, R.; MSL Science Team

    2013-10-01

    At the Rocknest location in Gale Crater, ChemCam collected measurements of the rocks surrounding the sandsheet. These rocks are potential in place outcrop related to the larger Yellowknife Bay exposure. ChemCam utilizes Laser Induced Breakdown Spectroscopy to provide elemental composition at distances up to 7 m from the rover. Analysis spot size ranges from 350 μm to 550 μm depending on range. A given analysis spot is fired upon repeatedly by the laser (generally from 30-50 laser shots) and the emission spectra from each laser shots is recorded. Elemental compositions are derived from the spectra vial a Partial Least Squares analysis model based a spectral library of ~70 certified standards collected on the flight instrument before launch. To date more than 60,000 spectra have been obtained on close to 2,000 observation points covering several hundred rock and soil samples. At Rocknest, even though each rock had a variety of textures, the chemistry of each rock varied in a similar manner. The rocks showed no evidence for widespread coatings or rinds. However, there was evidence for calcium sulfate (based on a linear relationship between CaO and SO4), and excess iron oxides (based on increased FeO not associated with SiO2 in specific rock targets). The detection of sulfates, ferric iron oxides and the overall chemistry of the rocks suggest that nearby felsic and olivine-rich material were cemented together by iron oxide cement. Results from the Rocknest area will be compared to other ChemCam results from other rocks at Yellowknife Bay and their geochemical/geological relationship will be presented. Implications for habitability of these deposits will also be discussed. Acknowledgement: This work has been conducted at the Jet Propulsion Laboratory, California Institute of Technology under a contract with the National Aeronautics and Space Administration. Funding from the Canadian Space Agency for King and Schmidt.

  16. Importance of reactive halogens in the tropical marine atmosphere using WRF-chem

    NASA Astrophysics Data System (ADS)

    Badia, Alba; Reeves, Claire E.; Baker, Alex; Volkamer, Rainer; Apel, Eric; Saiz-Lopez, Alfonso; von Glasow, Roland

    2017-04-01

    Halogen species (chlorine, bromine and iodine) are known to play an important role in the chemistry and oxidizing capacity of the troposphere, particularly in the marine boundary layer (MBL). Reactive halogens participate in catalytic reaction cycles that efficiently destroy O3, change the HOX and NOX partitioning, affect the oxidation of volatile organic compounds (VOCs) and mercury, reduce the lifetime of methane, and take part in new particle formation. Numerical models predicted that reactive halogen compounds account for 30% of O3 destruction in the MBL and 5-20% globally. Up to 34% of O3 loss in the tropical East Pacific is due to I and Br combined. Recent studies have highlighted the key role that heterogeneous chemistry plays in explaining observations of BrO and IO abundances in the tropical troposphere. The main objective of this study is to investigate the atmospheric chemistry in the tropical East Pacific with a focus on reactive halogens using the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) and field data from the TORERO campaign. Our reaction mechanism in WRF-Chem is based on the MOZART mechanism and has been extended to include bromine, chlorine and iodine chemistry. Heterogeneous recycling reactions involving sea-salt aerosol and other particles have been included into the model, along with oceanic emissions of important OVOCs and halocarbons. Sea surface emissions of inorganic iodine are calculated using the parameterisation of Carpenter et al., 2013. Focusing on TORERO observations from the ships and a selected number of flights we present the tropospheric impacts of halogens (BrO, IO) in the tropospheric chemistry of relevant species (O3, OH and OVOCS). Sensitivity runs are made in order to study the impact of heterogeneous chemistry in the iodine and bromine species partitioning. A comparison between the online calculation of Very Short Lived Halocarbons (VSLH) oceanic emissions with prescribed oceanic emissions is

  17. Formation Conditions of Basalts at Gale Crater, Mars from ChemCam Analyses

    NASA Astrophysics Data System (ADS)

    Filiberto, J.; Bridges, J.; Dasgupta, R.; Edwards, P.; Schwenzer, S. P.; Wiens, R. C.

    2015-12-01

    Surface igneous rocks shed light onto the chemistry, tectonic, and thermal state of planetary interiors. For the purpose of comparative planetology, therefore, it is critical to fully utilize the compositional diversity of igneous rocks for different terrestrial planets. For Mars, igneous float rocks and conglomerate clasts at Gale Crater, as analyzed by ChemCam [1] using a new calibration [2], have a larger range in chemistry than have been analyzed at any other landing site or within the Martian meteorite collection [3, 4]. These rocks may reflect different conditions of melting within the Martian interior than any previously analyzed basalts. Here we present new formation conditions for basaltic and trachybasalt/dioritic rocks at Gale Crater from ChemCam analyses following previous procedures [5, 6]. We then compare these estimates of basalt formation with previous estimates for rocks from the Noachian (Gusev Crater, Meridiani Planum, and a clast in the NWA 7034 meteorite [5, 6]), Hesperian (surface volcanics [7]), and Amazonian (surface volcanics and shergottites [7-8]), to calculate an average mantle potential temperature for different Martian epochs and investigate how the interior of Mars has changed through time. Finally, we will compare Martian mantle potential temperatures with petrologic estimate of cooling for the Earth. Our calculated estimate for the mantle potential temperature (TP) of rocks at Gale Crater is 1450 ± 45 °C which is within error of previous estimates for Noachian aged rocks [5, 6]. The TP estimates for the Hesperian and Amazonian, based on orbital analyses of the crust [7], are lower in temperature than the estimates for the Noachian. Our results are consistent with simple convective cooling of the Martian interior. [1] Wiens R. et al. (2012) Space Sci Rev 170. 167-227. [2] Anderson R. et al. (2015) LPSC. Abstract #7031. [3] Schmidt M.E. et al. (2014) JGRP 2013JE004481. [4] Sautter V. et al. (2014) JGRP 2013JE004472. [5] Filiberto J

  18. ConfChem Conference on Flipped Classroom: Reclaiming Face Time--How an Organic Chemistry Flipped Classroom Provided Access to Increased Guided Engagement

    ERIC Educational Resources Information Center

    Trogden, Bridget G.

    2015-01-01

    Students' active engagement is one of the most critical challenges to any successful learning environment. The blending of active engagement along with rich, meaningful content is necessary for chemical educators to re-examine the purpose of the chemistry classroom. The Spring 2014 ConfChem conference, Flipped Classroom, was held from May 9 to…

  19. Dust modeling over East Asia during the summer of 2010 using the WRF-Chem model

    NASA Astrophysics Data System (ADS)

    Zhang, B.; Huang, J.; Chen, S.

    2017-12-01

    An intense summer dust storm over East Asia during June 24-27, 2010, was systematically analyzed using the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) and a variety of in situ measurements and satellite retrievals. The results showed that the WRF-Chem model captured the spatial and temporal distributions of meteorological factors and dust aerosols over East Asia. This summer dust storm was initiated by the approach of a transverse trough in the northwestern Xinjiang. Because of the passage of the cutoff-low, a large amount of cold air was transported southward and further enhanced in the narrow valleys of the Altai and Tianshan Mountains, which resulted in higher wind speeds and huge dust emissions over the Taklimakan Desert (TD). Dust emission fluxes over the TD were as high as 54 μg m-2 s-1 on June 25th. The dust aerosols from the TD then swept across Inner Mongolia, Ningxia and Mongolia, and some were also transported eastward to Beijing, Tianjin, the Hebei region, and even South Korea and Japan. The simulations further showed that summer dust over East Asia exerts an important influence on the radiation budget in the Earth-atmosphere system. Dust heat the atmosphere at a maximum heating rate of 0.14 k day-1, effectively changing the vertical stability of the atmosphere and affecting climate change at regional and even global scales. The dust event-averaged direct radiative forcing induced by dust particles over the TD at all-sky was -6.0, -16.8 and 10.8 W m-2 at the top of the atmosphere, the surface, and in the atmosphere, respectively.

  20. Standardized toxicity testing may underestimate ecotoxicity: Environmentally relevant food rations increase the toxicity of silver nanoparticles to Daphnia.

    PubMed

    Stevenson, Louise M; Krattenmaker, Katherine E; Johnson, Erica; Bowers, Alexandra J; Adeleye, Adeyemi S; McCauley, Edward; Nisbet, Roger M

    2017-11-01

    Daphnia in the natural environment experience fluctuations in algal food supply, with periods when algal populations bloom and seasons when Daphnia have very little algal food. Standardized chronic toxicity tests, used for ecological risk assessment, dictate that Daphnia must be fed up to 400 times more food than they would experience in the natural environment (outside of algal blooms) for a toxicity test to be valid. This disconnect can lead to underestimating the toxicity of a contaminant. We followed the growth, reproduction, and survival of Daphnia exposed to 75 and 200 µg/L silver nanoparticles (AgNPs) at 4 food rations for up to 99 d and found that AgNP exposure at low, environmentally relevant food rations increased the toxicity of AgNPs. Exposure to AgNP at low food rations decreased the survival and/or reproduction of individuals, with potential consequences for Daphnia populations (based on calculated specific population growth rates). We also found tentative evidence that a sublethal concentration of AgNPs (75 µg/L) caused Daphnia to alter energy allocation away from reproduction and toward survival and growth. The present findings emphasize the need to consider resource availability, and not just exposure, in the environment when estimating the effect of a toxicant. Environ Toxicol Chem 2017;36:3008-3018. © 2017 SETAC. © 2017 SETAC.

  1. DayCent-Chem Simulations of Ecological and Biogeochemical Processes of Eight Mountain Ecosystems in the United States

    USGS Publications Warehouse

    Hartman, Melannie D.; Baron, Jill S.; Clow, David W.; Creed, Irena F.; Driscoll, Charles T.; Ewing, Holly A.; Haines, Bruce D.; Knoepp, Jennifer; Lajtha, Kate; Ojima, Dennis S.; Parton, William J.; Renfro, Jim; Robinson, R. Bruce; Van Miegroet, Helga; Weathers, Kathleen C.; Williams, Mark W.

    2009-01-01

    Atmospheric deposition of nitrogen (N) and sulfur (S) cause complex responses in ecosystems, from fertilization to forest ecosystem decline, freshwater eutrophication to acidification, loss of soil base cations, and alterations of disturbance regimes. DayCent-Chem, an ecosystem simulation model that combines ecosystem nutrient cycling and plant dynamics with aqueous geochemical equilibrium calculations, was developed to address ecosystem responses to combined atmospheric N and S deposition. It is unique among geochemically-based models in its dynamic biological cycling of N and its daily timestep for investigating ecosystem and surface water chemical response to episodic events. The model was applied to eight mountainous watersheds in the United States. The sites represent a gradient of N deposition across locales, from relatively pristine to N-saturated, and a variety of ecosystem types and climates. Overall, the model performed best in predicting stream chemistry for snowmelt-dominated sites. It was more difficult to predict daily stream chemistry for watersheds with deep soils, high amounts of atmospheric deposition, and a large degree of spatial heterogeneity. DayCent-Chem did well in representing plant and soil carbon and nitrogen pools and fluxes. Modeled stream nitrate (NO3-) and ammonium (NH4+) concentrations compared well with measurements at all sites, with few exceptions. Simulated daily stream sulfate (SO42-) concentrations compared well to measured values for sites where SO42- deposition has been low and where SO42- adsorption/desorption reactions did not seem to be important. The concentrations of base cations and silica in streams are highly dependent on the geochemistry and weathering rates of minerals in each catchment, yet these were rarely, if ever, known. Thus, DayCent-Chem could not accurately predict weathering products for some catchments. Additionally, few data were available for exchangeable soil cations or the magnitude of base cation

  2. Comment on "Simulation of Surface Ozone Pollution in the Central Gulf Coast Region Using WRF/Chem Model: Sensitivity to PBL and Land Surface Physics"

    EPA Science Inventory

    A recently published meteorology and air quality modeling study has several serious deficiencies deserving comment. The study uses the weather research and forecasting/chemistry (WRF/Chem) model to compare and evaluate boundary layer and land surface modeling options. The most se...

  3. Assessments of Potential Rock Coatings at Rocknest, Gale Crater with ChemCam

    NASA Technical Reports Server (NTRS)

    Blaney, D. L.; Anderson, R.; Berger, G.; Bridges, J.; Bridges, N.; Clark, B.; Clegg, S.; Ehlman, B.; Goetz, W.; King, P.; hide

    2013-01-01

    Many locations on Mars have low color contrast between the rocks and soils due to the rocks being "dusty"--basically having a surface that is spectrally similar to Martian soil. In general this has been interpreted as soil and/or dust clinging to the rock though either mechanical or electrostic processes. However, given the apparent mobility of thin films of water forming cemented soils on Mars and at Gale Crater, the possibility exists that some of these "dusty" surfaces may actually be coatings formed by thin films of water locally mobilizing soil/air fall material at the rock interface. This type of coating was observed by Spirit during an investigation of the rock Mazatzal which showed enhanced salts above "normal soil" and an enhancement of nano phase iron oxide that was 10 micronmeters thick. We decided to use ChemCam to investigate the possibility of similar rock coatings forming at the Rocknest site at Gale Crater.

  4. AMPTE/CCE CHEM observations of the energetic ion population at geosynchronous altitudes

    NASA Technical Reports Server (NTRS)

    Daglis, Ioannis A.; Sarris, Emmanuel T.; Wilken, Berend

    1993-01-01

    The paper presents results of a statistical study of average characteristics of the energetic ion population at geosynchronous altitudes, using energetic-ion (1-300 keV/e) measurements from the CHEM spectrometer aboard the AMPTE Charge Composition Explorer between January 1985 and June 1987. Data were sorted into four MLT groups and two extreme geomagnetic activity levels ('very quiet' for AE less than 30 nT and 'very active' for AE greater than 700 nT). A clear quiet-time dayside feature found in the measurements was a dip in H(+) and He(2+) spectra, at 6.6 keV/e in the prenoon sector and at 3.5 keV/e in the postnoon sector. During active times, the ion fluxes increased (except for He(+)), and the O(+) contribution to the total energy density increased dramatically. The pitch angle distributions were normal during quiet times and isotropic or field-aligned during active times.

  5. Chem I Supplement: Nutrition (Diet) and Athletics.

    ERIC Educational Resources Information Center

    Lineback, David R.

    1984-01-01

    Discusses various aspects related to nutrition and athletics. Examines nutritional requirements, energy use, carbohydrate loading, and myths and fallacies regarding food and athletic performance. Indicates that scientific evidence does not validate the use of any special diet by an athlete. (JN)

  6. Improvements to the WRF-Chem 3.5.1 model for quasi-hemispheric simulations of aerosols and ozone in the Arctic

    DOE PAGES

    Marelle, Louis; Raut, Jean-Christophe; Law, Kathy S.; ...

    2017-01-01

    In this study, the WRF-Chem regional model is updated to improve simulated short-lived pollutants (e.g., aerosols, ozone) in the Arctic. Specifically, we include in WRF-Chem 3.5.1 (with SAPRC-99 gas-phase chemistry and MOSAIC aerosols) (1) a correction to the sedimentation of aerosols, (2) dimethyl sulfide (DMS) oceanic emissions and gas-phase chemistry, (3) an improved representation of the dry deposition of trace gases over seasonal snow, and (4) an UV-albedo dependence on snow and ice cover for photolysis calculations. We also (5) correct the representation of surface temperatures over melting ice in the Noah Land Surface Model and (6) couple and further test the recent KF-CuP (Kain–Fritsch +more » Cumulus Potential) cumulus parameterization that includes the effect of cumulus clouds on aerosols and trace gases. The updated model is used to perform quasi-hemispheric simulations of aerosols and ozone, which are evaluated against surface measurements of black carbon (BC), sulfate, and ozone as well as airborne measurements of BC in the Arctic. The updated model shows significant improvements in terms of seasonal aerosol cycles at the surface and root mean square errors (RMSEs) for surface ozone, aerosols, and BC aloft, compared to the base version of the model and to previous large-scale evaluations of WRF-Chem in the Arctic. These improvements are mostly due to the inclusion of cumulus effects on aerosols and trace gases in KF-CuP (improved RMSE for surface BC and BC profiles, surface sulfate, and surface ozone), the improved surface temperatures over sea ice (surface ozone, BC, and sulfate), and the updated trace gas deposition and UV albedo over snow and ice (improved RMSE and correlation for surface ozone). DMS emissions and chemistry improve surface sulfate at all Arctic sites except Zeppelin, and correcting aerosol sedimentation has little influence on aerosols except in the upper troposphere.« less

  7. Improvements to the WRF-Chem 3.5.1 model for quasi-hemispheric simulations of aerosols and ozone in the Arctic

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Marelle, Louis; Raut, Jean-Christophe; Law, Kathy S.

    In this study, the WRF-Chem regional model is updated to improve simulated short-lived pollutants (e.g., aerosols, ozone) in the Arctic. Specifically, we include in WRF-Chem 3.5.1 (with SAPRC-99 gas-phase chemistry and MOSAIC aerosols) (1) a correction to the sedimentation of aerosols, (2) dimethyl sulfide (DMS) oceanic emissions and gas-phase chemistry, (3) an improved representation of the dry deposition of trace gases over seasonal snow, and (4) an UV-albedo dependence on snow and ice cover for photolysis calculations. We also (5) correct the representation of surface temperatures over melting ice in the Noah Land Surface Model and (6) couple and further test the recent KF-CuP (Kain–Fritsch +more » Cumulus Potential) cumulus parameterization that includes the effect of cumulus clouds on aerosols and trace gases. The updated model is used to perform quasi-hemispheric simulations of aerosols and ozone, which are evaluated against surface measurements of black carbon (BC), sulfate, and ozone as well as airborne measurements of BC in the Arctic. The updated model shows significant improvements in terms of seasonal aerosol cycles at the surface and root mean square errors (RMSEs) for surface ozone, aerosols, and BC aloft, compared to the base version of the model and to previous large-scale evaluations of WRF-Chem in the Arctic. These improvements are mostly due to the inclusion of cumulus effects on aerosols and trace gases in KF-CuP (improved RMSE for surface BC and BC profiles, surface sulfate, and surface ozone), the improved surface temperatures over sea ice (surface ozone, BC, and sulfate), and the updated trace gas deposition and UV albedo over snow and ice (improved RMSE and correlation for surface ozone). DMS emissions and chemistry improve surface sulfate at all Arctic sites except Zeppelin, and correcting aerosol sedimentation has little influence on aerosols except in the upper troposphere.« less

  8. A thorough analysis of a severe dust storm in the Arabian Peninsula using WRF-CHEM, satellite imagery, and ground observations

    NASA Astrophysics Data System (ADS)

    Karagulian, F.; Ghebreyesus, D. T.; Weston, M.; Krishnan, V.; Temimi, M.; Al Hammadi, F.; Al Abdooli, A.

    2017-12-01

    A strong dust event occurred over the Arabian Peninsula from 1 to 3 April 2015. The event impacted the United Arab Emirates (UAE) on 2 April 2015 in the form of a dust storm. The origin and synopsis of the event is investigated in this study together with its impact on Air Quality in the UAE. The Weather Research Forecasting model coupled with chemistry (WRF-Chem) was run for the dates of the dust event. Outputs of the model were assessed against ground measurements of Particulate Matter (PM10) from monitoring stations in the United Arab Emirates (UAE), meteorological data, and the Aerosol Optical Depth from the new 1 km Multi-Angle Implementation of Atmospheric Correction (MAIAC) algorithm for MODIS Terra and Aqua at 0.55 mm. Data from the geo-stationary satellite MSG SEVIRI was used to track the extent and the trajectory of the dust event across the Arabian Peninsula. This was supported by HYSPLIT back trajectory analysis simulated on hourly basis. The modeled results favorably agreed with ground observations of meteorological parameters at several monitoring stations in the UAE. On 2 and 3 April 2015, measurements and WRF-Chem simulations over the UAE showed northwest wind blowing within the range of 11-14 m s-1. Average surface temperature decreased from 33 to 26 ºC and the average radiance dropped by 50% during the peak time of the dust event with consequent reduction of the observed visibility down to 200 m in some UAE's cities. At local level, comparisons between modeled and estimated PM10 concentrations from monitoring stations and satellite data were somewhat biased by the saturated values recorded during the peak time of the dust event on 2 April 2015 with modeled lower limit average PM10 concentrations of 432 mg/m3 that were 25% lower than the ones from monitoring stations. On regional scale, the WRF-Chem model was able to estimate an upper limit values of PM10 concentrations during the dust event.

  9. Characterization of LIBS emission lines for the identification of chlorides, carbonates, and sulfates in salt/basalt mixtures for the application to MSL ChemCam data: LIBS OF CL, C, S IN SALT-BASALT MIXTURES

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Anderson, D. E.; Ehlmann, B. L.; Forni, O.

    Ancient environmental conditions on Mars can be probed through the identification of minerals on its surface, including water-deposited salts and cements dispersed in the pore space of sedimentary rocks. Laser-induced breakdown spectroscopy (LIBS) analyses by the Martian rover Curiosity's ChemCam instrument can indicate salts, and ChemCam surveys aid in identifying and selecting sites for further, detailed in situ analyses. Here, we performed laboratory LIBS experiments under simulated Mars conditions with a ChemCam-like instrument on a series of mixtures containing increasing concentrations of salt in a basaltic background to investigate the potential for identifying and quantifying chloride, carbonate, and sulfate saltsmore » found only in small amounts, dispersed in bulk rock with ChemCam, rather than concentrated in veins. The data then indicate that the presence of emission lines from the basalt matrix limited the number of Cl, C, and S emission lines found to be useful for quantitative analysis; nevertheless, several lines with intensities sensitive to salt concentration were identified. Detection limits for the elements based on individual emission lines ranged from ~20 wt % carbonate (2 wt % C), ~5–30 wt % sulfate (1–8 wt % S), and ~5–10 wt % chloride (3–6 wt % Cl) depending on the basaltic matrix and/or salt cation. Absolute quantification of Cl, C, and S in the samples via univariate analysis depends on the cation-anion pairing in the salt but appears relatively independent of matrices tested, following normalization. Our results are promising for tracking relative changes in the salt content of bulk rock on the Martian surface with ChemCam.« less

  10. Characterization of LIBS emission lines for the identification of chlorides, carbonates, and sulfates in salt/basalt mixtures for the application to MSL ChemCam data: LIBS OF CL, C, S IN SALT-BASALT MIXTURES

    DOE PAGES

    Anderson, D. E.; Ehlmann, B. L.; Forni, O.; ...

    2017-04-24

    Ancient environmental conditions on Mars can be probed through the identification of minerals on its surface, including water-deposited salts and cements dispersed in the pore space of sedimentary rocks. Laser-induced breakdown spectroscopy (LIBS) analyses by the Martian rover Curiosity's ChemCam instrument can indicate salts, and ChemCam surveys aid in identifying and selecting sites for further, detailed in situ analyses. Here, we performed laboratory LIBS experiments under simulated Mars conditions with a ChemCam-like instrument on a series of mixtures containing increasing concentrations of salt in a basaltic background to investigate the potential for identifying and quantifying chloride, carbonate, and sulfate saltsmore » found only in small amounts, dispersed in bulk rock with ChemCam, rather than concentrated in veins. The data then indicate that the presence of emission lines from the basalt matrix limited the number of Cl, C, and S emission lines found to be useful for quantitative analysis; nevertheless, several lines with intensities sensitive to salt concentration were identified. Detection limits for the elements based on individual emission lines ranged from ~20 wt % carbonate (2 wt % C), ~5–30 wt % sulfate (1–8 wt % S), and ~5–10 wt % chloride (3–6 wt % Cl) depending on the basaltic matrix and/or salt cation. Absolute quantification of Cl, C, and S in the samples via univariate analysis depends on the cation-anion pairing in the salt but appears relatively independent of matrices tested, following normalization. Our results are promising for tracking relative changes in the salt content of bulk rock on the Martian surface with ChemCam.« less

  11. Dust modeling over East Asia during the summer of 2010 using the WRF-Chem model

    NASA Astrophysics Data System (ADS)

    Chen, Siyu; Yuan, Tiangang; Zhang, Xiaorui; Zhang, Guolong; Feng, Taichen; Zhao, Dan; Zang, Zhou; Liao, Shujie; Ma, Xiaojun; Jiang, Nanxuan; Zhang, Jie; Yang, Fan; Lu, Hui

    2018-07-01

    An intense summer dust storm over East Asia during June 24-27, 2010, was systematically analyzed based on the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) and a variety of in situ measurements and satellite retrievals. The results showed that the WRF-Chem model captures the spatial and temporal distributions of meteorological factors and dust aerosol in summer over East Asia well. This summer dust storm is initiated by the approach of a transverse trough in the northwestern Xinjiang. Because of the passage of the cutoff-low, a large amount of cold air is transported southward and further enhanced by the narrow valleys of the Altai and Tianshan Mountains, which results in higher wind speeds and huge dust emissions over the Taklimakan Desert (TD). Dust emission fluxes over the TD areas are high as 54 μg m-2 s-1 on June 25. The dust aerosol from the TD then sweeps across Inner Mongolia, Ningxia and Mongolia, and some are also transported eastward to Beijing, Tianjin, Hebei, and even South Korea and Japan. The simulations further show that summer dust over East Asia exerts an important influence on the radiation budget in the Earth-atmosphere system. Dust heats the atmosphere at a maximum heating rate of 0.14 K day-1, effectively changing the vertical stability of the atmosphere and affecting climate change at regional and even global scales. The average direct radiative forcing induced by dust particles over the TD at all-sky is -6.0, -16.8 and 10.8 W m-2 at the top of the atmosphere, the surface, and in the atmosphere, respectively. The discussion about radiative forcing induced by summer dust provides confidence for future investigation of summer dust impact on cloud properties and precipitation efficiency in the eastern China.

  12. ConfChem Conference on Select 2016 BCCE Presentations: Changing Roles for Changing Times--Social Media and the Evolution of the Supplemental Instructor

    ERIC Educational Resources Information Center

    Alden, Emily

    2017-01-01

    This Communication summarizes one of the invited papers to the Select 2016 BCCE Presentations ACS CHED Committee on Computers in Chemical Education online ConfChem held from October 30 to November 22, 2016. The supplemental instruction (SI) model has come a long way from being a peer-assisted study sessions geared toward improving student…

  13. The AtChem On-line model and Electronic Laboratory Notebook (ELN): A free community modelling tool with provenance capture

    NASA Astrophysics Data System (ADS)

    Young, J. C.; Boronska, K.; Martin, C. J.; Rickard, A. R.; Vázquez Moreno, M.; Pilling, M. J.; Haji, M. H.; Dew, P. M.; Lau, L. M.; Jimack, P. K.

    2010-12-01

    AtChem On-line1 is a simple to use zero-dimensional box modelling toolkit, developed for use by laboratory, field and chamber scientists. Any set of chemical reactions can be simulated, in particular the whole Master Chemical Mechanism (MCM2) or any subset of it. Parameters and initial data can be provided through a self-explanatory web form and the resulting model is compiled and run on a dedicated server. The core part of the toolkit, providing a robust solver for thousands of chemical reactions, is written in Fortran and uses SUNDIALS3 CVODE libraries. Chemical systems can be constrained at multiple, user-determined timescales; this enabled studies of radical chemistry at one minute timescales. AtChem On-line is free to use and requires no installation - a web browser, text editor and any compressing software is all the user needs. CPU and storage are provided by the server (input and output data are saved indefinitely). An off-line version is also being developed, which will provide batch processing, an advanced graphical user interface and post-processing tools, for example, Rate of Production Analysis (ROPA) and chainlength analysis. The source code is freely available for advanced users wishing to adapt and run the program locally. Data management, dissemination and archiving are essential in all areas of science. In order to do this in an efficient and transparent way, there is a critical need to capture high quality metadata/provenance for modelling activities. An Electronic Laboratory Notebook (ELN) has been developed in parallel with AtChem Online as part of the EC EUROCHAMP24 project. In order to use controlled chamber experiments to evaluate the MCM, we need to be able to archive, track and search information on all associated chamber model runs, so that they can be used in subsequent mechanism development. Therefore it would be extremely useful if experiment and model metadata/provenance could be easily and automatically stored electronically

  14. Air pollution modeling over very complex terrain: An evaluation of WRF-Chem over Switzerland for two 1-year periods

    NASA Astrophysics Data System (ADS)

    Ritter, Mathias; Müller, Mathias D.; Tsai, Ming-Yi; Parlow, Eberhard

    2013-10-01

    The fully coupled chemistry module (WRF-Chem) within the Weather Research and Forecasting (WRF) model has been implemented over a Swiss domain for the years 2002 and 1991. The very complex terrain requires a high horizontal resolution (2 × 2 km2), which is achieved by nesting the Swiss domain into a coarser European one. The temporal and spatial distribution of O3, NO2 and PM10 as well as temperature and solar radiation are evaluated against ground-based measurements. The model performs well for the meteorological parameters with Pearson correlation coefficients of 0.92 for temperature and 0.88-0.89 for solar radiation. Temperature has root mean square errors (RMSE) of 3.30 K and 3.51 K for 2002 and 1991 and solar radiation has RMSEs of 122.92 and 116.35 for 2002 and 1991, respectively. For the modeled air pollutants, a multi-linear regression post-processing was used to eliminate systematic bias. Seasonal variations of post-processed air pollutants are represented correctly. However, short-term peaks of several days are not captured by the model. Averaged daily maximum and daily values of O3 achieved Pearson correlation coefficients of 0.69-0.77 whereas averaged NO2 and PM10 had the highest correlations for yearly average values (0.68-0.78). The spatial distribution reveals the importance of PM10 advection from the Po valley to southern Switzerland (Ticino). The absolute errors are ranging from - 10 to 15 μg/m3 for ozone, - 9 to 3 μg/m3 for NO2 and - 4 to 3 μg/m3 for PM10. However, larger errors occur along heavily trafficked roads, in street canyons or on mountains. We also compare yearly modeled results against a dedicated Swiss dispersion model for NO2 and PM10. The dedicated dispersion model has a slightly better statistical performance, but WRF-Chem is capable of computing the temporal evolution of three-dimensional data for a variety of air pollutants and meteorological parameters. Overall, WRF-Chem with the application of post-processing algorithms can

  15. Identification of "Known Unknowns" Utilizing Accurate Mass Data and ChemSpider

    NASA Astrophysics Data System (ADS)

    Little, James L.; Williams, Antony J.; Pshenichnov, Alexey; Tkachenko, Valery

    2012-01-01

    In many cases, an unknown to an investigator is actually known in the chemical literature, a reference database, or an internet resource. We refer to these types of compounds as "known unknowns." ChemSpider is a very valuable internet database of known compounds useful in the identification of these types of compounds in commercial, environmental, forensic, and natural product samples. The database contains over 26 million entries from hundreds of data sources and is provided as a free resource to the community. Accurate mass mass spectrometry data is used to query the database by either elemental composition or a monoisotopic mass. Searching by elemental composition is the preferred approach. However, it is often difficult to determine a unique elemental composition for compounds with molecular weights greater than 600 Da. In these cases, searching by the monoisotopic mass is advantageous. In either case, the search results are refined by sorting the number of references associated with each compound in descending order. This raises the most useful candidates to the top of the list for further evaluation. These approaches were shown to be successful in identifying "known unknowns" noted in our laboratory and for compounds of interest to others.

  16. Response to ``Comment on `Excitations in photoactive molecules from quantum Monte Carlo' '' [J. Chem. Phys. 122, 087101 (2005)

    NASA Astrophysics Data System (ADS)

    Filippi, Claudia; Buda, Francesco

    2005-02-01

    We find that regions of the excited state potential energy surface of formaldimine, which are accessible from the Franck-Condon configuration, are incorrectly described by the restricted open-shell Kohn-Sham (ROKS) approach. In these regions, the deviations of the ROKS energies from the time-dependent density functional theory results are not a simple shift. Contrary to what is argued in the Comment by Doltsinis and Fink [J. Chem. Phys.XX, XXX (2004)], these differences can play a role in the excited state molecular dynamics of formaldimine at finite temperature.

  17. University-School Partnerships: On the Impact on Students of Summer Schools (for School Students Aged 17-18) Run by Bristol ChemLabs

    ERIC Educational Resources Information Center

    Shaw, A. J.; Harrison, T. G.; Croker, S. J.; Medley, M.; Sellou, L.; Shallcross, K. L.; Williams, S, J.; Grayson, D. J.; Shallcross, D. E.

    2010-01-01

    Chemistry summer schools for 17-18 year old school students in the UK were run by Bristol ChemLabS, a Centre for Excellence in Teaching and Learning in Chemistry at the University of Bristol. Students attending were all studying Chemistry at post-16 level (A level in the UK) and experienced not only new practical techniques but also lectures on…

  18. ChemCam investigation of the John Klein and Cumberland drill holes and tailings, Gale crater, Mars

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Jackson, R. S.; Wiens, R. C.; Vaniman, D. T.

    The ChemCam instrument on the Mars Science Laboratory rover analyzed the rock surface, drill hole walls, tailings, and unprocessed and sieved dump piles to investigate chemical variations with depth in the first two martian drill holes and possible fractionation or segregation effects of the drilling and sample processing. Furthermore, the drill sites are both in Sheepbed Mudstone, the lowest exposed member of the Yellowknife Bay formation. Yellowknife Bay is composed of detrital basaltic materials in addition to clay minerals and an amorphous component. The drill tailings are a mixture of basaltic sediments and diagenetic material like calcium sulfate veins, whilemore » the shots on the drill site surface and walls of the drill holes are closer to those pure end members. The sediment dumped from the sample acquisition, processing, and handling subsystem is of similar composition to the tailings; however, due to the specifics of the drilling process the tailings and dump piles come from different depths within the hole. This then allows the ChemCam instrument to analyze samples representing the bulk composition from different depths. On the pre-drill surfaces, the Cumberland site has a greater amount of CaO and evidence for calcium sulfate veins, than the John Klein site. But, John Klein has a greater amount of calcium sulfate veins below the surface, as seen in mapping, drill hole wall analysis, and observations in the drill tailings and dump pile. In addition, the Cumberland site does not have any evidence of variations in bulk composition with depth down the drill hole, while the John Klein site has evidence for a greater amount of CaO (calcium sulfates) in the top portion of the hole compared to the middle section of the hole, where the drill sample was collected.« less

  19. ChemCam investigation of the John Klein and Cumberland drill holes and tailings, Gale crater, Mars

    DOE PAGES

    Jackson, R. S.; Wiens, R. C.; Vaniman, D. T.; ...

    2016-05-13

    The ChemCam instrument on the Mars Science Laboratory rover analyzed the rock surface, drill hole walls, tailings, and unprocessed and sieved dump piles to investigate chemical variations with depth in the first two martian drill holes and possible fractionation or segregation effects of the drilling and sample processing. Furthermore, the drill sites are both in Sheepbed Mudstone, the lowest exposed member of the Yellowknife Bay formation. Yellowknife Bay is composed of detrital basaltic materials in addition to clay minerals and an amorphous component. The drill tailings are a mixture of basaltic sediments and diagenetic material like calcium sulfate veins, whilemore » the shots on the drill site surface and walls of the drill holes are closer to those pure end members. The sediment dumped from the sample acquisition, processing, and handling subsystem is of similar composition to the tailings; however, due to the specifics of the drilling process the tailings and dump piles come from different depths within the hole. This then allows the ChemCam instrument to analyze samples representing the bulk composition from different depths. On the pre-drill surfaces, the Cumberland site has a greater amount of CaO and evidence for calcium sulfate veins, than the John Klein site. But, John Klein has a greater amount of calcium sulfate veins below the surface, as seen in mapping, drill hole wall analysis, and observations in the drill tailings and dump pile. In addition, the Cumberland site does not have any evidence of variations in bulk composition with depth down the drill hole, while the John Klein site has evidence for a greater amount of CaO (calcium sulfates) in the top portion of the hole compared to the middle section of the hole, where the drill sample was collected.« less

  20. Source apportionment of atmospheric mercury pollution in China using the GEOS-Chem model.

    PubMed

    Wang, Long; Wang, Shuxiao; Zhang, Lei; Wang, Yuxuan; Zhang, Yanxu; Nielsen, Chris; McElroy, Michael B; Hao, Jiming

    2014-07-01

    China is the largest atmospheric mercury (Hg) emitter in the world. Its Hg emissions and environmental impacts need to be evaluated. In this study, China's Hg emission inventory is updated to 2007 and applied in the GEOS-Chem model to simulate the Hg concentrations and depositions in China. Results indicate that simulations agree well with observed background Hg concentrations. The anthropogenic sources contributed 35-50% of THg concentration and 50-70% of total deposition in polluted regions. Sensitivity analysis was performed to assess the impacts of mercury emissions from power plants, non-ferrous metal smelters and cement plants. It is found that power plants are the most important emission sources in the North China, the Yangtze River Delta (YRD) and the Pearl River Delta (PRD) while the contribution of non-ferrous metal smelters is most significant in the Southwest China. The impacts of cement plants are significant in the YRD, PRD and Central China. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Modeling urban air pollution in Budapest using WRF-Chem model

    NASA Astrophysics Data System (ADS)

    Kovács, Attila; Leelőssy, Ádám; Lagzi, István; Mészáros, Róbert

    2017-04-01

    Air pollution is a major problem for urban areas since the industrial revolution, including Budapest, the capital and largest city of Hungary. The main anthropogenic sources of air pollutants are industry, traffic and residential heating. In this study, we investigated the contribution of major industrial point sources to the urban air pollution in Budapest. We used the WRF (Weather Research and Forecasting) nonhydrostatic mesoscale numerical weather prediction system online coupled with chemistry (WRF-Chem, version 3.6).The model was configured with three nested domains with grid spacings of 15, 5 and 1 km, representing Central Europe, the Carpathian Basin and Budapest with its surrounding area. Emission data was obtained from the National Environmental Information System. The point source emissions were summed in their respective cells in the second nested domain according to latitude-longitude coordinates. The main examined air pollutants were carbon monoxide (CO) and nitrogen oxides (NOx), from which the secondary compound, ozone (O3) forms through chemical reactions. Simulations were performed under different weather conditions and compared to observations from the automatic monitoring site of the Hungarian Air Quality Network. Our results show that the industrial emissions have a relatively weak role in the urban background air pollution, confirming the effect of industrial developments and regulations in the recent decades. However, a few significant industrial sources and their impact area has been demonstrated.

  2. Towards a Comprehensive Dynamic-chemistry Assimilation for Eos-Chem: Plans and Status in NASA's Data Assimilation Office

    NASA Technical Reports Server (NTRS)

    Pawson, Steven; Lin, Shian-Jiann; Rood, Richard B.; Stajner, Ivanka; Nebuda, Sharon; Nielsen, J. Eric; Douglass, Anne R.

    2000-01-01

    In order to support the EOS-Chem project, a comprehensive assimilation package for the coupled chemical-dynamical system is being developed by the Data Assimilation Office at NASA GSFC. This involves development of a coupled chemistry/meteorology model and of data assimilation techniques for trace species and meteorology. The model is being developed using the flux-form semi-Lagrangian dynamical core of Lin and Rood, the physical parameterizations from the NCAR Community Climate Model, and atmospheric chemistry modules from the Atmospheric Chemistry and Dynamics branch at NASA GSFC. To date the following results have been obtained: (i) multi-annual simulations with the dynamics-radiation model show the credibility of the package for atmospheric simulations; (ii) initial simulations including a limited number of middle atmospheric trace gases reveal the realistic nature of transport mechanisms, although there is still a need for some improvements. Samples of these results will be shown. A meteorological assimilation system is currently being constructed using the model; this will form the basis for the proposed meteorological/chemical assimilation package. The latter part of the presentation will focus on areas targeted for development in the near and far terms, with the objective of Providing a comprehensive assimilation package for the EOS-Chem science experiment. The first stage will target ozone assimilation. The plans also encompass a reanalysis (ReSTS) for the 1991-1995 period, which includes the Mt. Pinatubo eruption and the time when a large number of UARS observations were available. One of the most challenging aspects of future developments will be to couple theoretical advances in tracer assimilation with the practical considerations of a real environment and eventually a near-real-time assimilation system.

  3. Comment on "Study of dielectric relaxations of anhydrous trehalose and maltose glasses" [J. Chem. Phys. 134, 014508 (2011)].

    PubMed

    Kaminski, K; Wlodarczyk, P; Paluch, M

    2011-10-28

    Very recently Kwon et al. [H.-J. Kwon, J.-A. Seo, H. K. Kim, and Y. H. Hwang, J. Chem. Phys. 134, 014508 (2011)] published an article on the study of dielectric relaxation in trehalose and maltose glasses. They carried out broadband dielectric measurements at very wide range of temperatures covering supercooled liquid as well as glassy state of both saccharides. It is worth to mention that authors have also applied a new method for obtaining anhydrous glasses of trehalose and maltose that enables avoiding their caramelization. Four relaxation processes were identified in dielectric spectra of both saccharides. The slower one was identified as structural relaxation process the next one, not observed by the others, was assigned as Johari-Goldstein (JG) β-relaxation, while the last two secondary modes were of the same nature as found by Kaminski et al. [K. Kaminski, E. Kaminska, P. Wlodarczyk, S. Pawlus, D. Kimla, A. Kasprzycka, M. Paluch, J. Ziolo, W. Szeja, and K. L. Ngai, J. Phys. Chem. B 112, 12816 (2008)]. In this comment we show that the authors mistakenly assigned the slowest relaxation process as structural mode of disaccharides. We have proven that this relaxation process is an effect of formation of thin layer of air or water between plate of capacitor and sample. The same effect can be observed if plates of capacitor are oxidized. Thus, we concluded that their slowest mode is connected to the dc conduction process while their β JG process is primary relaxation of trehalose and maltose.

  4. Top-down Estimate of Dust Emissions Through Integration of MODIS and MISR Aerosol Retrievals With the Geos-chem Adjoint Model

    NASA Technical Reports Server (NTRS)

    Wang, Jun; Xu, Xiaoguang; Henze, Daven K.; Zeng, Jing; Ji, Qiang; Tsay, Si-Chee; Huang, Jianping

    2012-01-01

    Predicting the influences of dust on atmospheric composition, climate, and human health requires accurate knowledge of dust emissions, but large uncertainties persist in quantifying mineral sources. This study presents a new method for combined use of satellite-measured radiances and inverse modeling to spatially constrain the amount and location of dust emissions. The technique is illustrated with a case study in May 2008; the dust emissions in Taklimakan and Gobi deserts are spatially optimized using the GEOSChem chemical transport model and its adjoint constrained by aerosol optical depth (AOD) that are derived over the downwind dark-surface region in China from MODIS (Moderate Resolution Imaging Spectroradiometer) reflectance with the aerosol single scattering properties consistent with GEOS-chem. The adjoint inverse modeling yields an overall 51% decrease in prior dust emissions estimated by GEOS-Chem over the Taklimakan-Gobi area, with more significant reductions south of the Gobi Desert. The model simulation with optimized dust emissions shows much better agreement with independent observations from MISR (Multi-angle Imaging SpectroRadiometer) AOD and MODIS Deep Blue AOD over the dust source region and surface PM10 concentrations. The technique of this study can be applied to global multi-sensor remote sensing data for constraining dust emissions at various temporal and spatial scales, and hence improving the quantification of dust effects on climate, air quality, and human health.

  5. Is ozone model bias driven by errors in cloud predictions? A quantitative assessment using satellite cloud retrievals in WRF-Chem

    NASA Astrophysics Data System (ADS)

    Ryu, Y. H.; Hodzic, A.; Barré, J.; Descombes, G.; Minnis, P.

    2017-12-01

    Clouds play a key role in radiation and hence O3 photochemistry by modulating photolysis rates and light-dependent emissions of biogenic volatile organic compounds (BVOCs). It is not well known, however, how much of the bias in O3 predictions is caused by inaccurate cloud predictions. This study quantifies the errors in surface O3 predictions associated with clouds in summertime over CONUS using the Weather Research and Forecasting with Chemistry (WRF-Chem) model. Cloud fields used for photochemistry are corrected based on satellite cloud retrievals in sensitivity simulations. It is found that the WRF-Chem model is able to detect about 60% of clouds in the right locations and generally underpredicts cloud optical depths. The errors in hourly O3 due to the errors in cloud predictions can be up to 60 ppb. On average in summertime over CONUS, the errors in 8-h average O3 of 1-6 ppb are found to be attributable to those in cloud predictions under cloudy sky conditions. The contribution of changes in photolysis rates due to clouds is found to be larger ( 80 % on average) than that of light-dependent BVOC emissions. The effects of cloud corrections on O­3 are about 2 times larger in VOC-limited than NOx-limited regimes, suggesting that the benefits of accurate cloud predictions would be greater in VOC-limited than NOx-limited regimes.

  6. Pre-flight calibration and initial data processing for the ChemCam laser-induced breakdown spectroscopy instrument on the Mars Science Laboratory rover

    USGS Publications Warehouse

    Wiens, R.C.; Maurice, S.; Lasue, J.; Forni, O.; Anderson, R.B.; Clegg, S.; Bender, S.; Blaney, D.; Barraclough, B.L.; Cousin, A.; DeFlores, L.; Delapp, D.; Dyar, M.D.; Fabre, C.; Gasnault, O.; Lanza, N.; Mazoyer, J.; Melikechi, N.; Meslin, P.-Y.; Newsom, H.; Ollila, A.; Perez, R.; Tokar, R.; Vaniman, D.

    2013-01-01

    The ChemCam instrument package on the Mars Science Laboratory rover, Curiosity, is the first planetary science instrument to employ laser-induced breakdown spectroscopy (LIBS) to determine the compositions of geological samples on another planet. Pre-processing of the spectra involves subtracting the ambient light background, removing noise, removing the electron continuum, calibrating for the wavelength, correcting for the variable distance to the target, and applying a wavelength-dependent correction for the instrument response. Further processing of the data uses multivariate and univariate comparisons with a LIBS spectral library developed prior to launch as well as comparisons with several on-board standards post-landing. The level-2 data products include semi-quantitative abundances derived from partial least squares regression. A LIBS spectral library was developed using 69 rock standards in the form of pressed powder disks, glasses, and ceramics to minimize heterogeneity on the scale of the observation (350–550 μm dia.). The standards covered typical compositional ranges of igneous materials and also included sulfates, carbonates, and phyllosilicates. The provenance and elemental and mineralogical compositions of these standards are described. Spectral characteristics of this data set are presented, including the size distribution and integrated irradiances of the plasmas, and a proxy for plasma temperature as a function of distance from the instrument. Two laboratory-based clones of ChemCam reside in Los Alamos and Toulouse for the purpose of adding new spectra to the database as the need arises. Sensitivity to differences in wavelength correlation to spectral channels and spectral resolution has been investigated, indicating that spectral registration needs to be within half a pixel and resolution needs to match within 1.5 to 2.6 pixels. Absolute errors are tabulated for derived compositions of each major element in each standard using PLS regression

  7. Constraints on Eurasian ship NOx emissions using OMI NO2 observations and GEOS-Chem

    NASA Astrophysics Data System (ADS)

    Vinken, Geert C. M.; Boersma, Folkert; van Donkelaar, Aaron; Zhang, Lin

    2013-04-01

    Ships emit large quantities of nitrogen oxides (NOx = NO + NO2), important precursors for ozone (O3) and particulate matter formation. Ships burn low-grade marine heavy fuel due to the limited regulations that exist for the maritime sector in international waters. Previous studies showed that global ship NOx emission inventories amount to 3.0-10.4 Tg N per year (15-30% of total NOx emissions), with most emissions close to land and affecting air quality in densely populated coastal regions. Bottom-up inventories depend on the extrapolation of a relatively small number of measurements that are often unable to capture annual emission changes and can suffer from large uncertainties. Satellites provide long-term, high-resolution retrievals that can be used to improve emission estimates. In this study we provide top-down constraints on ship NOx emissions in major European ship routes, using observed NO2 columns from the Ozone Monitoring Instrument (OMI) and NO2 columns simulated with the nested (0.5°×0.67°) version of the GEOS-Chem chemistry transport model. We use a plume-in-grid treatment of ship NOx emissions to account for in-plume chemistry in our model. We ensure consistency between the retrievals and model simulations by using the high-resolution GEOS-Chem NO2 profiles as a priori. We find evidence that ship emissions in the Mediterranean Sea are geographically misplaced by up to 150 km and biased high by a factor of 4 as compared to the most recent (EMEP) ship emission inventory. Better agreement is found over the shipping lane between Spain and the English Channel. We extend our approach and also provide constraints for major ship routes in the Red Sea and Indian Ocean. Using the full benefit of the long-term retrieval record of OMI, we present a new Eurasian ship emission inventory for the years 2005 to 2010, based on the EMEP and AMVER-ICOADS inventories, and top-down constraints from the satellite retrievals. Our work shows that satellite retrievals can

  8. Chem I Supplement: Emphasis on Acids and Bases

    ERIC Educational Resources Information Center

    Journal of Chemical Education Staff

    1977-01-01

    Provides supplementary notes on acids and bases suitable for secondary school chemistry instruction, including acidity in solid and natural waters, acidity balance in body chemistry, acid and basic foods, pH values of common fluids, examples of drugs, and commercial preparation of nitric acid. (SL)

  9. Using sulfur stable isotopes to assess mercury bioaccumulation and biomagnification in temperate lake food webs.

    PubMed

    Clayden, Meredith G; Lescord, Gretchen L; Kidd, Karen A; Wang, Xiaowa; Muir, Derek C G; O'Driscoll, Nelson J

    2017-03-01

    Nitrogen and carbon stable isotopes (δ 15 N, δ 13 C) are commonly used to understand mercury (Hg) bioaccumulation and biomagnification in freshwater food webs. Though sulfur isotopes (δ 34 S) can distinguish between energy sources from the water column (aqueous sulfate) and from sediments to freshwater organisms, little is known about whether δ 34 S can help interpret variable Hg concentrations in aquatic species or food webs. Seven acidic lakes in Kejimkujik National Park (Nova Scotia, Canada) were sampled for biota, water, and sediments in 2009 and 2010. Fishes, zooplankton, and macroinvertebrates were analyzed for δ 34 S, δ 15 N, δ 13 C, and Hg (methyl Hg in invertebrates, total Hg in fishes); aqueous sulfate and profundal sediments were analyzed for δ 34 S. Within lakes, mean δ 34 S values in sediments and sulfate differed between 0.53‰ and 1.98‰, limiting their use as tracers of energy sources to the food webs. However, log-Hg and δ 34 S values were negatively related (slopes -0.14 to -0.35, R 2 0.20-0.39, p < 0.001-0.01) through each food web, and slopes were significantly different among lakes (analysis of covariance, lake × δ 34 S interaction term p = 0.04). Despite these relationships, multiple regression analyses within each taxon showed that biotic Hg concentrations were generally better predicted by δ 15 N and/or δ 13 C. The results indicate that δ 34 S values are predictive of Hg concentrations in these food webs, although the mechanisms underlying these relationships warrant further study. Environ Toxicol Chem 2017;36:661-670. © 2016 SETAC. © 2016 SETAC.

  10. Determination of chloramphenicol in milk powder using liquid-liquid cartridge extraction (Chem Elut) and liquid chromatography-tandem mass spectrometry.

    PubMed

    Zawadzka, Iwona; Rodziewicz, Lech

    2014-01-01

    The European Union prohibits the use of chloramphenicol (CAP) as a veterinary drug in food-producing animals. Nevertheless, CAP have been detected in milk products (liquid milk and milk powder). Therefore, it is necessary to develop sensitive methods for determining CAP residues in milk powder. The aim of this study was to develop and validate a confirmatory method for determination of CAP in milk powder. Chloramphenicol was determined in milk powder using LC-ESI-MS/MS in negative mode. After fat removing milk powder sample was extracted/cleaned-up with a Chem Elut extraction cartridge. Separation was achieved on a Phenomenex Luna C-18 column with acetonitrile-water as a mobile phase. The mass spectrometer was operated in multiple reaction monitoring mode (MRM). Four transitions were monitored m/z 321→152, 321→194, 321→257 (CAP) and 326→157 (IS CAP-d5). Linearity, accuracy, precision, decision limit (CCa), detection capability (CCb) and ruggedness were determined for m/z 321→152. The mean relative recoveries (inter standard-corrected) of CAP from whole milk powder spiked at levels 0.1, 0.2, 0.3 and 0.6 mg/kg were in the range 95 - 103%. Relative standard deviation (RSD%) of recoveries at all spiked levels were less than 14%. RSDs within-laboratory reproducibility calculated at fortification of 0.3 mg/kg was less than 16%. CCa and CCb were below 0.1 mg/kg. The developed LC-MS/MS method allows the determination of CAP in milk powder. The method was validated according to the Commission Decision No. 2002/657/EC requirements. This method can be applied to determination CAP in whole and skim milk powder.

  11. Sources, seasonality, and trends of Southeast US aerosol: an integrated analysis of surface, aircraft, and satellite observations with the GEOS-Chem chemical transport model

    NASA Astrophysics Data System (ADS)

    Kim, P. S.; Jacob, D. J.; Fisher, J. A.; Travis, K.; Yu, K.; Zhu, L.; Yantosca, R. M.; Sulprizio, M. P.; Jimenez, J. L.; Campuzano-Jost, P.; Froyd, K. D.; Liao, J.; Hair, J. W.; Fenn, M. A.; Butler, C. F.; Wagner, N. L.; Gordon, T. D.; Welti, A.; Wennberg, P. O.; Crounse, J. D.; St. Clair, J. M.; Teng, A. P.; Millet, D. B.; Schwarz, J. P.; Markovic, M. Z.; Perring, A. E.

    2015-07-01

    We use an ensemble of surface (EPA CSN, IMPROVE, SEARCH, AERONET), aircraft (SEAC4RS), and satellite (MODIS, MISR) observations over the Southeast US during the summer-fall of 2013 to better understand aerosol sources in the region and the relationship between surface particulate matter (PM) and aerosol optical depth (AOD). The GEOS-Chem global chemical transport model (CTM) with 25 km × 25 km resolution over North America is used as a common platform to interpret measurements of different aerosol variables made at different times and locations. Sulfate and organic aerosol (OA) are the main contributors to surface PM2.5 (mass concentration of PM finer than 2.5 μm aerodynamic diameter) and AOD over the Southeast US. GEOS-Chem simulation of sulfate requires a missing oxidant, taken here to be stabilized Criegee intermediates, but which could alternatively reflect an unaccounted for heterogeneous process. Biogenic isoprene and monoterpenes account for 60 % of OA, anthropogenic sources for 30 %, and open fires for 10 %. 60 % of total aerosol mass is in the mixed layer below 1.5 km, 20 % in the cloud convective layer at 1.5-3 km, and 20 % in the free troposphere above 3 km. This vertical profile is well captured by GEOS-Chem, arguing against a high-altitude source of OA. The extent of sulfate neutralization (f = [NH4+]/(2[SO42-] + [NO3-])) is only 0.5-0.7 mol mol-1 in the observations, despite an excess of ammonia present, which could reflect suppression of ammonia uptake by organic aerosol. This would explain the long-term decline of ammonium aerosol in the Southeast US, paralleling that of sulfate. The vertical profile of aerosol extinction over the Southeast US follows closely that of aerosol mass. GEOS-Chem reproduces observed total column aerosol mass over the Southeast US within 6 %, column aerosol extinction within 16 %, and space-based AOD within 21 %. The large AOD decline observed from summer to winter is driven by sharp declines in both sulfate and OA from

  12. Comment on “Frequency-domain stimulated and spontaneous light emission signals at molecular junctions” [J. Chem. Phys. 141, 074107 (2014)

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Galperin, Michael; Ratner, Mark A.; Nitzan, Abraham

    2015-04-07

    We discuss the derivation of the optical response in molecular junctions presented by U. Harbola et al. [J. Chem. Phys. 141, 074107 (2014)], which questions some terms in the theory of Raman scattering in molecular junctions developed in our earlier publications. We show that the terms considered in our theory represent the correct contribution to calculated Raman scattering and are in fact identical to those considered by Harbola et al. We also indicate drawbacks of the presented approach in treating the quantum transport part of the problem.

  13. Design and Development of ChemInfoCloud: An Integrated Cloud Enabled Platform for Virtual Screening.

    PubMed

    Karthikeyan, Muthukumarasamy; Pandit, Deepak; Bhavasar, Arvind; Vyas, Renu

    2015-01-01

    The power of cloud computing and distributed computing has been harnessed to handle vast and heterogeneous data required to be processed in any virtual screening protocol. A cloud computing platorm ChemInfoCloud was built and integrated with several chemoinformatics and bioinformatics tools. The robust engine performs the core chemoinformatics tasks of lead generation, lead optimisation and property prediction in a fast and efficient manner. It has also been provided with some of the bioinformatics functionalities including sequence alignment, active site pose prediction and protein ligand docking. Text mining, NMR chemical shift (1H, 13C) prediction and reaction fingerprint generation modules for efficient lead discovery are also implemented in this platform. We have developed an integrated problem solving cloud environment for virtual screening studies that also provides workflow management, better usability and interaction with end users using container based virtualization, OpenVz.

  14. Chem I Supplement: Effects of Ethanol on Nutrition.

    ERIC Educational Resources Information Center

    Shorey, RoseAnn L.

    1979-01-01

    Malnutrition due to alcoholism is discussed. It includes energy from the metabolism of ethanol as it contributes to obesity, the replacement of nutritious foods by sources of ethanol, inhibition of vitamins being activated, the increase in excretion of valuable minerals, and toxicity to cells of organ systems. (Author/SA)

  15. Sensitivity Analysis of PM2.5 in Seoul to Emissions and Reaction Rates Using the GEOS-Chem and its Adjoint Model

    NASA Astrophysics Data System (ADS)

    Lee, H. M.; Park, R.; Henze, D. K.; Shim, C.; Shin, H. J.; Song, I. H.; Park, J. S.; Park, S. M.; Moon, K. J.

    2015-12-01

    The sources of PM2.5 are poorly quantified in Seoul, Korea, where tens of millions of populations are daily exposed to the exceedance of PM2.5 concentrations to the air quality criteria. We used a global 3-D chemical transport model (GEOS-Chem) and its adjoint to investigate the sensitivities of PM2.5 concentrations in Seoul to emission sources, sectors, and chemical reaction rates. We first conduct forward model simulations using a nested version of GEOS-Chem with 0.25°x0.3125° spatial resolutions in East Asia for July 2012 - July 2013. We evaluated the model by comparing it with PM2.5 mass and chemical composition observations at National Institute of Environmental Research sites in Korea. The model reasonably reproduces the observed seasonal variability of PM2.5 concentrations (R=0.3-0.6), but tends to overestimate the observations in summer and underestimate them in winter. Our sensitivity analyses show the dominant contributions from local emission sources to PM2.5 concentrations in Seoul compared to the trans-boundary transport influences from the outside, which are important for long-lived tracers in spring. Other results including the model sensitivity to input parameters and the updated emissions are used to improve the model performance and to provide strategic information for the KORUS-AQ flight measurement campaign in May-June, 2016.

  16. Operational on-line coupled chemical weather forecasts for Europe with WRF/Chem

    NASA Astrophysics Data System (ADS)

    Hirtl, Marcus; Mantovani, Simone; Krüger, Bernd C.; Flandorfer, Claudia; Langer, Matthias

    2014-05-01

    Air quality is a key element for the well-being and quality of life of European citizens. Air pollution measurements and modeling tools are essential for the assessment of air quality according to EU legislation. The responsibilities of ZAMG as the national weather service of Austria include the support of the federal states and the public in questions connected to the protection of the environment in the frame of advisory and counseling services as well as expert opinions. ZAMG conducts daily Air-Quality forecasts using the on-line coupled model WRF/Chem. Meteorology is simulated simultaneously with the emissions, turbulent mixing, transport, transformation, and fate of trace gases and aerosols. The emphasis of the application is on predicting pollutants over Austria. Two domains are used for the simulations: the mother domain covers Europe with a resolution of 12 km, the inner domain includes the alpine region with a horizontal resolution of 4 km; 45 model levels are used in the vertical direction. The model runs 2 times per day for a period of 72 hours and is initialized with ECMWF forecasts. On-line coupled models allow considering two-way interactions between different atmospheric processes including chemistry (both gases and aerosols), clouds, radiation, boundary layer, emissions, meteorology and climate. In the operational set-up direct-, indirect and semi-direct effects between meteorology and air chemistry are enabled. The model is running on the HPCF (High Performance Computing Facility) of the ZAMG. In the current set-up 1248 CPUs are used. As the simulations need a big amount of computing resources, a method to safe I/O-time was implemented. Every MPI task writes all its output into the shared memory filesystem of the compute nodes. Once the WRF/Chem integration is finished, all split NetCDF-files are merged and saved on the global file system. The merge-routine is based on parallel-NetCDF. With this method the model runs about 30% faster on the SGI

  17. Photochemical Pollution Modeling of Ozone at Metropolitan Area of Porto Alegre - RS/Brazil using WRF/Chem

    NASA Astrophysics Data System (ADS)

    Cuchiara, G. C.; Carvalho, J.

    2013-05-01

    One of the main problems related to air pollution in urban areas is caused by photochemical oxidants, particularly troposphere ozone (O3), which is considered a harmful substance. The O3 precursors (carbon monoxide CO, nitrogen oxides NOx and hydrocarbons HCs) are predominantly of anthropogenic origin in these areas, and vehicles are the main emission sources. Due to the increased urbanization and industrial development in recent decades, air pollutant emissions have increased likewise, mainly by mobile sources in the highly urbanized and developed areas, such as the Metropolitan Area of Porto Alegre-RS (MAPA). According to legal regulations implemented in Brazil in 2005, which aimed at increasing the fraction of biofuels in the national energy matrix, 2% biodiesel were supposed to be added to the fuel mixture within three years, and up to 5% after eight years of implementation of these regulations. Our work performs an analysis of surface concentrations for O3, NOx, CO, and HCs through numerical simulations with WRF/Chem (Weather Research and Forecasting model with Chemistry). The model is validated against observational data obtained from the local urban air quality network for the period from January 5 to 9, 2009 (96 hours). One part of the study focused on the comparison of simulated meteorological variables, to observational data from two stations in MAPA. The results showed that the model simulates well the diurnal evolution of pressure and temperature at the surface, but is much less accurate for wind speed. Another part included the evaluation of model results of WRF/Chem for O3 versus observed data at air quality stations Esteio and Porto Alegre. Comparisons between simulated and observed O3 revealed that the model simulates well the evolution of the observed values, but on many occasions the model did not reproduce well the maximum and minimum concentrations. Finally, a preliminary quantitative sensitivity study on the impact of biofuel on the

  18. Spectroscopic studies of the reaction between bovine serum amine oxidase (copper-containing) and some hydrazides and hydrazines.

    PubMed Central

    Morpurgo, L; Befani, O; Sabatini, S; Mondovì, B; Artico, M; Corelli, F; Massa, S; Stefancich, G; Avigliano, L

    1988-01-01

    The carbonyl cofactor of bovine serum amine oxidase, recently identified as pyrroloquinoline quinone [Ameyama, Hayashi, Matsushita, Shinagawa & Adachi (1984) Agric. Biol. Chem. 48, 561-565; Lobenstein-Verbeek, Jongejan, Frank & Duine (1984) FEBS Lett. 170, 305-309], reacts stoichiometrically and irreversibly with hydrazides of phenylacetic acid and of benzoic acid. With the phenylacetic hydrazides a reversible intermediate step was detected by competition with substrate, carbonylic reagents or phenylhydrazine, a typical inhibitor of the enzyme. All hydrazides form an intense broad band with maximum absorbance in a narrow wavelength range (350-360 nm), irrespective of the acyl group, suggesting that the transition is located on the organic cofactor. A different situation is found with some phenylhydrazines, where extended conjugation can occur between the cofactor and the phenyl pi-electron system via the azo group, as shown by the lower energy and higher intensity of the transition. In this case the transition is sensitive to substituents in the phenyl ring. The c.d. spectrum of the adducts is influenced by the type of hydrazide (derived from phenylacetic acid or benzoic acid), by pH and by NN-diethyldithiocarbamate binding to copper, probably as a result of shifts of equilibria between hydrazone-azo tautomers. PMID:3146976

  19. Modeling Urban Air Quality in the Berlin-Brandenburg Region: Evaluation of a WRF-Chem Setup

    NASA Astrophysics Data System (ADS)

    Kuik, F.; Churkina, G.; Butler, T. M.; Lauer, A.; Mar, K. A.

    2015-12-01

    Air pollution is the number one environmental cause of premature deaths in Europe. Despite extensive regulations, air pollution remains a challenging issue, especially in urban areas. For studying air quality in the Berlin-Brandenburg region of Germany the Weather Research and Forecasting Model with Chemistry (WRF-Chem) is set up and evaluated against meteorological and air quality observations from monitoring stations as well as from a field campaign conducted in 2014 (incl. black carbon, VOCs as well as mobile measurements of particle size distribution and particle mass). The model setup includes 3 nested domains with horizontal resolutions of 15km, 3km, and 1km, online biogenic emissions using MEGAN 2.0, and anthropogenic emissions from the TNO-MACC-II inventory. This work serves as a basis for future studies on different aspects of air pollution in the Berlin-Brandenburg region, including how heat waves affect emissions of biogenic volatile organic compounds (BVOC) from urban vegetation (summer 2006) and the impact of selected traffic measures on air quality in the Berlin-Brandenburg area (summer 2014). The model represents the meteorology as observed in the region well for both periods. An exception is the heat wave period in 2006, where the temperature simulated with 3km and 1km resolutions is biased low by around 2°C for urban built-up stations. First results of simulations with chemistry show that, on average, WRF-Chem simulates concentrations of O3 well. However, the 8 hr maxima are underestimated, and the minima are overestimated. While NOx daily means are modeled reasonably well for urban stations, they are overestimated for suburban stations. PM10 concentrations are underestimated by the model. The biases and correlation coefficients of simulated O3, NOx, and PM10 in comparison to surface observations do not show improvements for the 1km domain in comparison to the 3km domain. To improve the model performance of the 1km domain we will include an

  20. Multiyear applications of WRF/Chem over continental U.S.: Model evaluation, variation trend, and impacts of boundary conditions

    NASA Astrophysics Data System (ADS)

    Yahya, Khairunnisa; He, Jian; Zhang, Yang

    2015-12-01

    Multiyear applications of an online-coupled meteorology-chemistry model allow an assessment of the variation trends in simulated meteorology, air quality, and their interactions to changes in emissions and meteorology, as well as the impacts of initial and boundary conditions (ICONs/BCONs) on simulated aerosol-cloud-radiation interactions over a period of time. In this work, the Weather Research and Forecasting model with Chemistry version 3.4.1 (WRF/Chem v. 3.4.1) with the 2005 Carbon Bond mechanism coupled with the Volatility Basis Set module for secondary organic aerosol formation (WRF/Chem-CB05-VBS) is applied for multiple years (2001, 2006, and 2010) over continental U.S. This work also examines the changes in simulated air quality and meteorology due to changes in emissions and meteorology and the model's capability in reproducing the observed variation trends in species concentrations from 2001 to 2010. In addition, the impacts of the chemical ICONs/BCONs on model predictions are analyzed. ICONs/BCONs are downscaled from two global models, the modified Community Earth System Model/Community Atmosphere model version 5.1 (CESM/CAM v5.1) and the Monitoring Atmospheric Composition and Climate model (MACC). The evaluation of WRF/Chem-CB05-VBS simulations with the CESM ICONs/BCONs for 2001, 2006, and 2010 shows that temperature at 2 m (T2) is underpredicted for all three years likely due to inaccuracies in soil moisture and soil temperature, resulting in biases in surface relative humidity, wind speed, and precipitation. With the exception of cloud fraction, other aerosol-cloud variables including aerosol optical depth, cloud droplet number concentration, and cloud optical thickness are underpredicted for all three years, resulting in overpredictions of radiation variables. The model performs well for O3 and particulate matter with diameter less than or equal to 2.5 (PM2.5) for all three years comparable to other studies from literature. The model is able to

  1. Study of key factors influencing dust emission: An assessment of GEOS-Chem and DEAD simulations with observations

    NASA Astrophysics Data System (ADS)

    Bartlett, Kevin S.

    Mineral dust aerosols can impact air quality, climate change, biological cycles, tropical cyclone development and flight operations due to reduced visibility. Dust emissions are primarily limited to the extensive arid regions of the world, yet can negatively impact local to global scales, and are extremely complex to model accurately. Within this dissertation, the Dust Entrainment And Deposition (DEAD) model was adapted to run, for the first known time, using high temporal (hourly) and spatial (0.3°x0.3°) resolution data to methodically interrogate the key parameters and factors influencing global dust emissions. The dependence of dust emissions on key parameters under various conditions has been quantified and it has been shown that dust emissions within DEAD are largely determined by wind speeds, vegetation extent, soil moisture and topographic depressions. Important findings were that grid degradation from 0.3ºx0.3º to 1ºx1º, 2ºx2.5º, and 4°x5° of key meteorological, soil, and surface input parameters greatly reduced emissions approximately 13% and 29% and 64% respectively, as a result of the loss of sub grid detail within these key parameters at coarse grids. After running high resolution DEAD emissions globally for 2 years, two severe dust emission cases were chosen for an in-depth investigation of the root causes of the events and evaluation of the 2°x2.5° Goddard Earth Observing System (GEOS)-Chem and 0.3°x0.3° DEAD model capabilities to simulate the events: one over South West Asia (SWA) in June 2008 and the other over the Middle East in July 2009. The 2 year lack of rain over SWA preceding June 2008 with a 43% decrease in mean rainfall, yielded less than normal plant growth, a 28% increase in Aerosol Optical Depth (AOD), and a 24% decrease in Meteorological Aerodrome Report (METAR) observed visibility (VSBY) compared to average years. GEOS-Chem captured the observed higher AOD over SWA in June 2008. More detailed comparisons of GEOS-Chem

  2. Development and application of a regional-scale atmospheric mercury model based on WRF/Chem: a Mediterranean area investigation.

    PubMed

    Gencarelli, Christian Natale; De Simone, Francesco; Hedgecock, Ian Michael; Sprovieri, Francesca; Pirrone, Nicola

    2014-03-01

    The emission, transport, deposition and eventual fate of mercury (Hg) in the Mediterranean area has been studied using a modified version of the Weather Research and Forecasting model coupled with Chemistry (WRF/Chem). This model version has been developed specifically with the aim to simulate the atmospheric processes determining atmospheric Hg emissions, concentrations and deposition online at high spatial resolution. For this purpose, the gas phase chemistry of Hg and a parametrised representation of atmospheric Hg aqueous chemistry have been added to the regional acid deposition model version 2 chemical mechanism in WRF/Chem. Anthropogenic mercury emissions from the Arctic Monitoring and Assessment Programme included in the emissions preprocessor, mercury evasion from the sea surface and Hg released from biomass burning have also been included. Dry and wet deposition processes for Hg have been implemented. The model has been tested for the whole of 2009 using measurements of total gaseous mercury from the European Monitoring and Evaluation Programme monitoring network. Speciated measurement data of atmospheric elemental Hg, gaseous oxidised Hg and Hg associated with particulate matter, from a Mediterranean oceanographic campaign (June 2009), has permitted the model's ability to simulate the atmospheric redox chemistry of Hg to be assessed. The model results highlight the importance of both the boundary conditions employed and the accuracy of the mercury speciation in the emission database. The model has permitted the reevaluation of the deposition to, and the emission from, the Mediterranean Sea. In light of the well-known high concentrations of methylmercury in a number of Mediterranean fish species, this information is important in establishing the mass balance of Hg for the Mediterranean Sea. The model results support the idea that the Mediterranean Sea is a net source of Hg to the atmosphere and suggest that the net flux is ≈30 Mg year(-1) of elemental Hg.

  3. Evaluation of UTLS Carbon Monoxide Simulations in GMI and GEOS-Chem Chemical Transport Models using Aura MLS Observations

    NASA Technical Reports Server (NTRS)

    Huang, Lei; Jiang, Jonathan H.; Murray, Lee T.; Damon, Megan R.; Su, Hui; Livesey, Nathaniel J.

    2016-01-01

    This study evaluates the distribution and variation of carbon monoxide (CO) in the upper troposphere and lower stratosphere (UTLS) during 2004-2012 as simulated by two chemical transport models, using the latest version of Aura Microwave Limb Sounder (MLS) observations. The simulated spatial distributions, temporal variations and vertical transport of CO in the UTLS region are compared with those observed by MLS. We also investigate the impact of surface emissions and deep convection on CO concentrations in the UTLS over different regions, using both model simulations and MLS observations. Global Modeling Initiative (GMI) and GEOS-Chem simulations of UTLS CO both show similar spatial distributions to observations. The global mean CO values simulated by both models agree with MLS observations at 215 and 147 hPa, but are significantly underestimated by more than 40% at 100 hPa. In addition, the models underestimate the peak CO values by up to 70% at 100 hPa, 60% at 147 hPa and 40% at 215 hPa, with GEOS-Chem generally simulating more CO at 100 hPa and less CO at 215 hPa than GMI. The seasonal distributions of CO simulated by both models are in better agreement with MLS in the Southern Hemisphere (SH) than in the Northern Hemisphere (NH), with disagreements between model and observations over enhanced CO regions such as southern Africa. The simulated vertical transport of CO shows better agreement with MLS in the tropics and the SH subtropics than the NH subtropics. We also examine regional variations in the relationships among surface CO emission, convection and UTLS CO concentrations. The two models exhibit emission-convection- CO relationships similar to those observed by MLS over the tropics and some regions with enhanced UTLS CO.

  4. The potassic sedimentary rocks in Gale Crater, Mars, as seen by ChemCam on board Curiosity: Potassic Sedimentary Rocks, Gale Crater

    DOE PAGES

    Le Deit, L.; Mangold, N.; Forni, O.; ...

    2016-05-13

    The Mars Science Laboratory rover Curiosity encountered potassium-rich clastic sedimentary rocks at two sites in Gale Crater, the waypoints Cooperstown and Kimberley. These rocks include several distinct meters thick sedimentary outcrops ranging from fine sandstone to conglomerate, interpreted to record an ancient fluvial or fluvio-deltaic depositional system. Furthermore, from ChemCam Laser-Induced Breakdown Spectroscopy (LIBS) chemical analyses, this suite of sedimentary rocks has an overall mean K 2O abundance that is more than 5 times higher than that of the average Martian crust. The combined analysis of ChemCam data with stratigraphic and geographic locations then reveals that the mean K 2Omore » abundance increases upward through the stratigraphic section. Chemical analyses across each unit can be represented as mixtures of several distinct chemical components, i.e., mineral phases, including K-bearing minerals, mafic silicates, Fe-oxides, and Fe-hydroxide/oxyhydroxides. Possible K-bearing minerals include alkali feldspar (including anorthoclase and sanidine) and K-bearing phyllosilicate such as illite. Mixtures of different source rocks, including a potassium-rich rock located on the rim and walls of Gale Crater, are the likely origin of observed chemical variations within each unit. Physical sorting may have also played a role in the enrichment in K in the Kimberley formation. The occurrence of these potassic sedimentary rocks provides additional evidence for the chemical diversity of the crust exposed at Gale Crater.« less

  5. The potassic sedimentary rocks in Gale Crater, Mars, as seen by ChemCam on board Curiosity: Potassic Sedimentary Rocks, Gale Crater

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Le Deit, L.; Mangold, N.; Forni, O.

    The Mars Science Laboratory rover Curiosity encountered potassium-rich clastic sedimentary rocks at two sites in Gale Crater, the waypoints Cooperstown and Kimberley. These rocks include several distinct meters thick sedimentary outcrops ranging from fine sandstone to conglomerate, interpreted to record an ancient fluvial or fluvio-deltaic depositional system. Furthermore, from ChemCam Laser-Induced Breakdown Spectroscopy (LIBS) chemical analyses, this suite of sedimentary rocks has an overall mean K 2O abundance that is more than 5 times higher than that of the average Martian crust. The combined analysis of ChemCam data with stratigraphic and geographic locations then reveals that the mean K 2Omore » abundance increases upward through the stratigraphic section. Chemical analyses across each unit can be represented as mixtures of several distinct chemical components, i.e., mineral phases, including K-bearing minerals, mafic silicates, Fe-oxides, and Fe-hydroxide/oxyhydroxides. Possible K-bearing minerals include alkali feldspar (including anorthoclase and sanidine) and K-bearing phyllosilicate such as illite. Mixtures of different source rocks, including a potassium-rich rock located on the rim and walls of Gale Crater, are the likely origin of observed chemical variations within each unit. Physical sorting may have also played a role in the enrichment in K in the Kimberley formation. The occurrence of these potassic sedimentary rocks provides additional evidence for the chemical diversity of the crust exposed at Gale Crater.« less

  6. Developing and validating predictive decision tree models from mining chemical structural fingerprints and high-throughput screening data in PubChem.

    PubMed

    Han, Lianyi; Wang, Yanli; Bryant, Stephen H

    2008-09-25

    Recent advances in high-throughput screening (HTS) techniques and readily available compound libraries generated using combinatorial chemistry or derived from natural products enable the testing of millions of compounds in a matter of days. Due to the amount of information produced by HTS assays, it is a very challenging task to mine the HTS data for potential interest in drug development research. Computational approaches for the analysis of HTS results face great challenges due to the large quantity of information and significant amounts of erroneous data produced. In this study, Decision Trees (DT) based models were developed to discriminate compound bioactivities by using their chemical structure fingerprints provided in the PubChem system http://pubchem.ncbi.nlm.nih.gov. The DT models were examined for filtering biological activity data contained in four assays deposited in the PubChem Bioassay Database including assays tested for 5HT1a agonists, antagonists, and HIV-1 RT-RNase H inhibitors. The 10-fold Cross Validation (CV) sensitivity, specificity and Matthews Correlation Coefficient (MCC) for the models are 57.2 approximately 80.5%, 97.3 approximately 99.0%, 0.4 approximately 0.5 respectively. A further evaluation was also performed for DT models built for two independent bioassays, where inhibitors for the same HIV RNase target were screened using different compound libraries, this experiment yields enrichment factor of 4.4 and 9.7. Our results suggest that the designed DT models can be used as a virtual screening technique as well as a complement to traditional approaches for hits selection.

  7. Advances in molecular quantum chemistry contained in the Q-Chem 4 program package

    NASA Astrophysics Data System (ADS)

    Shao, Yihan; Gan, Zhengting; Epifanovsky, Evgeny; Gilbert, Andrew T. B.; Wormit, Michael; Kussmann, Joerg; Lange, Adrian W.; Behn, Andrew; Deng, Jia; Feng, Xintian; Ghosh, Debashree; Goldey, Matthew; Horn, Paul R.; Jacobson, Leif D.; Kaliman, Ilya; Khaliullin, Rustam Z.; Kuś, Tomasz; Landau, Arie; Liu, Jie; Proynov, Emil I.; Rhee, Young Min; Richard, Ryan M.; Rohrdanz, Mary A.; Steele, Ryan P.; Sundstrom, Eric J.; Woodcock, H. Lee, III; Zimmerman, Paul M.; Zuev, Dmitry; Albrecht, Ben; Alguire, Ethan; Austin, Brian; Beran, Gregory J. O.; Bernard, Yves A.; Berquist, Eric; Brandhorst, Kai; Bravaya, Ksenia B.; Brown, Shawn T.; Casanova, David; Chang, Chun-Min; Chen, Yunqing; Chien, Siu Hung; Closser, Kristina D.; Crittenden, Deborah L.; Diedenhofen, Michael; DiStasio, Robert A., Jr.; Do, Hainam; Dutoi, Anthony D.; Edgar, Richard G.; Fatehi, Shervin; Fusti-Molnar, Laszlo; Ghysels, An; Golubeva-Zadorozhnaya, Anna; Gomes, Joseph; Hanson-Heine, Magnus W. D.; Harbach, Philipp H. P.; Hauser, Andreas W.; Hohenstein, Edward G.; Holden, Zachary C.; Jagau, Thomas-C.; Ji, Hyunjun; Kaduk, Benjamin; Khistyaev, Kirill; Kim, Jaehoon; Kim, Jihan; King, Rollin A.; Klunzinger, Phil; Kosenkov, Dmytro; Kowalczyk, Tim; Krauter, Caroline M.; Lao, Ka Un; Laurent, Adèle D.; Lawler, Keith V.; Levchenko, Sergey V.; Lin, Ching Yeh; Liu, Fenglai; Livshits, Ester; Lochan, Rohini C.; Luenser, Arne; Manohar, Prashant; Manzer, Samuel F.; Mao, Shan-Ping; Mardirossian, Narbe; Marenich, Aleksandr V.; Maurer, Simon A.; Mayhall, Nicholas J.; Neuscamman, Eric; Oana, C. Melania; Olivares-Amaya, Roberto; O'Neill, Darragh P.; Parkhill, John A.; Perrine, Trilisa M.; Peverati, Roberto; Prociuk, Alexander; Rehn, Dirk R.; Rosta, Edina; Russ, Nicholas J.; Sharada, Shaama M.; Sharma, Sandeep; Small, David W.; Sodt, Alexander; Stein, Tamar; Stück, David; Su, Yu-Chuan; Thom, Alex J. W.; Tsuchimochi, Takashi; Vanovschi, Vitalii; Vogt, Leslie; Vydrov, Oleg; Wang, Tao; Watson, Mark A.; Wenzel, Jan; White, Alec; Williams, Christopher F.; Yang, Jun; Yeganeh, Sina; Yost, Shane R.; You, Zhi-Qiang; Zhang, Igor Ying; Zhang, Xing; Zhao, Yan; Brooks, Bernard R.; Chan, Garnet K. L.; Chipman, Daniel M.; Cramer, Christopher J.; Goddard, William A., III; Gordon, Mark S.; Hehre, Warren J.; Klamt, Andreas; Schaefer, Henry F., III; Schmidt, Michael W.; Sherrill, C. David; Truhlar, Donald G.; Warshel, Arieh; Xu, Xin; Aspuru-Guzik, Alán; Baer, Roi; Bell, Alexis T.; Besley, Nicholas A.; Chai, Jeng-Da; Dreuw, Andreas; Dunietz, Barry D.; Furlani, Thomas R.; Gwaltney, Steven R.; Hsu, Chao-Ping; Jung, Yousung; Kong, Jing; Lambrecht, Daniel S.; Liang, WanZhen; Ochsenfeld, Christian; Rassolov, Vitaly A.; Slipchenko, Lyudmila V.; Subotnik, Joseph E.; Van Voorhis, Troy; Herbert, John M.; Krylov, Anna I.; Gill, Peter M. W.; Head-Gordon, Martin

    2015-01-01

    A summary of the technical advances that are incorporated in the fourth major release of the Q-Chem quantum chemistry program is provided, covering approximately the last seven years. These include developments in density functional theory methods and algorithms, nuclear magnetic resonance (NMR) property evaluation, coupled cluster and perturbation theories, methods for electronically excited and open-shell species, tools for treating extended environments, algorithms for walking on potential surfaces, analysis tools, energy and electron transfer modelling, parallel computing capabilities, and graphical user interfaces. In addition, a selection of example case studies that illustrate these capabilities is given. These include extensive benchmarks of the comparative accuracy of modern density functionals for bonded and non-bonded interactions, tests of attenuated second order Møller-Plesset (MP2) methods for intermolecular interactions, a variety of parallel performance benchmarks, and tests of the accuracy of implicit solvation models. Some specific chemical examples include calculations on the strongly correlated Cr2 dimer, exploring zeolite-catalysed ethane dehydrogenation, energy decomposition analysis of a charged ter-molecular complex arising from glycerol photoionisation, and natural transition orbitals for a Frenkel exciton state in a nine-unit model of a self-assembling nanotube.

  8. Maximum unbiased validation (MUV) data sets for virtual screening based on PubChem bioactivity data.

    PubMed

    Rohrer, Sebastian G; Baumann, Knut

    2009-02-01

    Refined nearest neighbor analysis was recently introduced for the analysis of virtual screening benchmark data sets. It constitutes a technique from the field of spatial statistics and provides a mathematical framework for the nonparametric analysis of mapped point patterns. Here, refined nearest neighbor analysis is used to design benchmark data sets for virtual screening based on PubChem bioactivity data. A workflow is devised that purges data sets of compounds active against pharmaceutically relevant targets from unselective hits. Topological optimization using experimental design strategies monitored by refined nearest neighbor analysis functions is applied to generate corresponding data sets of actives and decoys that are unbiased with regard to analogue bias and artificial enrichment. These data sets provide a tool for Maximum Unbiased Validation (MUV) of virtual screening methods. The data sets and a software package implementing the MUV design workflow are freely available at http://www.pharmchem.tu-bs.de/lehre/baumann/MUV.html.

  9. Modelling Poly-Aromatic Hydrocarbons "online" with the GEOS-Chem Europe and Asia regional models.

    NASA Astrophysics Data System (ADS)

    Ivatt, P.; Evans, M. J.

    2017-12-01

    Poly-Aromatic Hydrocarbons (PAHs) are carcinogens and so are restricted by international treaties. PAHs are mainly emitted into the atmosphere by domestic (heating and cooking), natural (forest fires burning), as well as some industrial processes (coke ovens). PAHs partition between the gas and particle phase (notably carbonaceous particles) based on their volatility. In recent years, interest has turned to the possible health effects of their oxidation products (both nitrogenated and oxygenated) as it has been suggested that these oxidation products may be even more carcinogenic than the parent PAHs. To increase our understanding of the processes controlling the regional concentrations of PAHs and their oxidation products an "online" PAH model has been developed within the GEOS-Chem framework. This provides for the representation of the coupled aerosol/gas phase chemistry of the parent PAH and its secondary oxidation products. Benzo[a]pyrene is used as an exemplar but the methodology is flexible and the approach can be used for any PAH species. Comparisons are made with observations and the sources of variability discussed.

  10. ChemCam passive reflectance spectroscopy of the Lubango, Okoruso, and Oudam drill targets in Gale Crater, Mars

    NASA Astrophysics Data System (ADS)

    Johnson, J. R.; Cloutis, E.; Fraeman, A.; Wiens, R. C.; Maurice, S.; Blaney, D. L.; Gasnault, O.

    2016-12-01

    The ChemCam laser-induced breakdown spectroscopy instrument on the MSL rover Curiosity was used in passive mode (without the laser) to obtain relative reflectance spectra (400-840 nm) of drill tailings and sieved dump piles associated with the targets Lubango, Okoruso, and Oudam between mission sols 1324-1369 near the base of Mt. Sharp. The Lubango and Okoruso drill holes were studied to compare the light-toned zones in the Stimson sandstone (Lubango; 61 wt % SiO2 from ChemCam LIBS data) with nearby unaltered materials (Okoruso; 42 wt % SiO2). Passive spectra of the Lubango tailings (derived from 1-2 cm near the surface) were 50% brighter than the sieved samples (obtained from >2 cm depths). All samples exhibited flat spectra with a slight decrease in reflectance toward the near-infrared. The presence of a weak band near 433 nm (from trace ferric materials such as ferric sulfate) was likely enhanced by the relatively transparent, silica-rich matrix. Lubango was spectrally similar to Greenhorn, another high-silica alteration zone observed in the Stimson unit (Sol 1139). Okoruso passive spectra exhibited flat but increasing reflectance towards the near-infrared with a minor downturn past 800 nm likely related to minor pyroxene. The spectra were darker than the Lubango sieved samples, with no evidence for a 433 nm band. They were similar to the spectra of Big Sky (the unaltered Stimson companion observation to Greenhorn). The Oudam drill tailings pile was observed at two locations: along its outer edge and at a more inward location. Both areas exhibited broad bands near 535 nm and 670 nm and a near-infrared dropoff consistent with hematite. Peak reflectances were near 785 nm for the edge sample but closer to 765 nm for the inner surface (similar to the hematite-bearing Confidence Hills sample from Sol 762). The difference likely results from the presence of other ferric materials in addition to hematite along the edge. This may indicate minor variations in oxidation

  11. The EnVision++ system: a new immunohistochemical method for diagnostics and research. Critical comparison with the APAAP, ChemMate, CSA, LABC, and SABC techniques.

    PubMed

    Sabattini, E; Bisgaard, K; Ascani, S; Poggi, S; Piccioli, M; Ceccarelli, C; Pieri, F; Fraternali-Orcioni, G; Pileri, S A

    1998-07-01

    To assess a newly developed immunohistochemical detection system, the EnVision++. A large series of differently processed normal and pathological samples and 53 relevant monoclonal antibodies were chosen. A chessboard titration assay was used to compare the results provided by the EnVision++ system with those of the APAAP, CSA, LSAB, SABC, and ChemMate methods, when applied either manually or in a TechMate 500 immunostainer. With the vast majority of the antibodies, EnVision++ allowed two- to fivefold higher dilutions than the APAAP, LSAB, SABC, and ChemMate techniques, the staining intensity and percentage of expected positive cells being the same. With some critical antibodies (such as the anti-CD5), it turned out to be superior in that it achieved consistently reproducible results with differently fixed or overfixed samples. Only the CSA method, which includes tyramide based enhancement, allowed the same dilutions as the EnVision++ system, and in one instance (with the anti-cyclin D1 antibody) represented the gold standard. The EnVision++ is an easy to use system, which avoids the possibility of disturbing endogenous biotin and lowers the cost per test by increasing the dilutions of the primary antibodies. Being a two step procedure, it reduces both the assay time and the workload.

  12. Representation of the Community Earth System Model (CESM1) CAM4-chem within the Chemistry-Climate Model Initiative (CCMI)

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tilmes, Simone; Lamarque, Jean -Francois; Emmons, Louisa K.

    The Community Earth System Model (CESM1) CAM4-chem has been used to perform the Chemistry Climate Model Initiative (CCMI) reference and sensitivity simulations. In this model, the Community Atmospheric Model version 4 (CAM4) is fully coupled to tropospheric and stratospheric chemistry. Details and specifics of each configuration, including new developments and improvements are described. CESM1 CAM4-chem is a low-top model that reaches up to approximately 40 km and uses a horizontal resolution of 1.9° latitude and 2.5° longitude. For the specified dynamics experiments, the model is nudged to Modern-Era Retrospective Analysis for Research and Applications (MERRA) reanalysis. We summarize the performance ofmore » the three reference simulations suggested by CCMI, with a focus on the last 15 years of the simulation when most observations are available. Comparisons with selected data sets are employed to demonstrate the general performance of the model. We highlight new data sets that are suited for multi-model evaluation studies. Most important improvements of the model are the treatment of stratospheric aerosols and the corresponding adjustments for radiation and optics, the updated chemistry scheme including improved polar chemistry and stratospheric dynamics and improved dry deposition rates. These updates lead to a very good representation of tropospheric ozone within 20 % of values from available observations for most regions. In particular, the trend and magnitude of surface ozone is much improved compared to earlier versions of the model. Furthermore, stratospheric column ozone of the Southern Hemisphere in winter and spring is reasonably well represented. In conclusion, all experiments still underestimate CO most significantly in Northern Hemisphere spring and show a significant underestimation of hydrocarbons based on surface observations.« less

  13. Representation of the Community Earth System Model (CESM1) CAM4-chem within the Chemistry-Climate Model Initiative (CCMI)

    DOE PAGES

    Tilmes, Simone; Lamarque, Jean -Francois; Emmons, Louisa K.; ...

    2016-05-20

    The Community Earth System Model (CESM1) CAM4-chem has been used to perform the Chemistry Climate Model Initiative (CCMI) reference and sensitivity simulations. In this model, the Community Atmospheric Model version 4 (CAM4) is fully coupled to tropospheric and stratospheric chemistry. Details and specifics of each configuration, including new developments and improvements are described. CESM1 CAM4-chem is a low-top model that reaches up to approximately 40 km and uses a horizontal resolution of 1.9° latitude and 2.5° longitude. For the specified dynamics experiments, the model is nudged to Modern-Era Retrospective Analysis for Research and Applications (MERRA) reanalysis. We summarize the performance ofmore » the three reference simulations suggested by CCMI, with a focus on the last 15 years of the simulation when most observations are available. Comparisons with selected data sets are employed to demonstrate the general performance of the model. We highlight new data sets that are suited for multi-model evaluation studies. Most important improvements of the model are the treatment of stratospheric aerosols and the corresponding adjustments for radiation and optics, the updated chemistry scheme including improved polar chemistry and stratospheric dynamics and improved dry deposition rates. These updates lead to a very good representation of tropospheric ozone within 20 % of values from available observations for most regions. In particular, the trend and magnitude of surface ozone is much improved compared to earlier versions of the model. Furthermore, stratospheric column ozone of the Southern Hemisphere in winter and spring is reasonably well represented. In conclusion, all experiments still underestimate CO most significantly in Northern Hemisphere spring and show a significant underestimation of hydrocarbons based on surface observations.« less

  14. Geochemistry of the Bagnold dune field as observed by ChemCam and comparison with other aeolian deposits at Gale Crater

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Agnes, Cousin; Dehouck, Erwin; Meslin, Pierre-Yves

    The Curiosity rover conducted the first field investigation of an active extraterrestrial dune. Our study of the Bagnold dunes focuses on the ChemCam chemical results and also presents findings on the grain size distributions based on the ChemCam RMI and MAHLI images. These active dunes are composed of grains that are mostly <250 μm. Their composition is overall similar to that of the aeolian deposits analyzed all along the traverse (“Aeolis Palus soils”). Nevertheless, the dunes contain less volatiles (Cl, H, S) than the Aeolis Palus soils, which appears to be due to a lower content of volatile-rich fine-grained particlesmore » (<100 μm), or a lower content of volatile-rich amorphous component, possibly as a result of: 1) a lower level of chemical alteration; 2) the removal of an alteration rind at the surface of the grains during transport; 3) a lower degree of interaction with volcanic gases/aerosols; or 4) physical sorting that removed the smallest and most altered grains. Analyses of the >150 μm grain-size dump piles have shown that coarser grains (150-250 μm) are enriched in the mafic elements Fe and Mn, suggesting a larger content in olivine compared to smaller grains (<150 μm) of the Bagnold dunes. Furthermore, the chemistry of soils analyzed in the vicinity of the dunes indicates that they are similar to the dune material. Altogether these observations suggest that the olivine content determined by X-ray diffraction of the <150 μm grain-size sample should be considered as a lower limit for the Bagnold dunes.« less

  15. Geochemistry of the Bagnold dune field as observed by ChemCam and comparison with other aeolian deposits at Gale Crater

    DOE PAGES

    Agnes, Cousin; Dehouck, Erwin; Meslin, Pierre-Yves; ...

    2017-06-27

    The Curiosity rover conducted the first field investigation of an active extraterrestrial dune. Our study of the Bagnold dunes focuses on the ChemCam chemical results and also presents findings on the grain size distributions based on the ChemCam RMI and MAHLI images. These active dunes are composed of grains that are mostly <250 μm. Their composition is overall similar to that of the aeolian deposits analyzed all along the traverse (“Aeolis Palus soils”). Nevertheless, the dunes contain less volatiles (Cl, H, S) than the Aeolis Palus soils, which appears to be due to a lower content of volatile-rich fine-grained particlesmore » (<100 μm), or a lower content of volatile-rich amorphous component, possibly as a result of: 1) a lower level of chemical alteration; 2) the removal of an alteration rind at the surface of the grains during transport; 3) a lower degree of interaction with volcanic gases/aerosols; or 4) physical sorting that removed the smallest and most altered grains. Analyses of the >150 μm grain-size dump piles have shown that coarser grains (150-250 μm) are enriched in the mafic elements Fe and Mn, suggesting a larger content in olivine compared to smaller grains (<150 μm) of the Bagnold dunes. Furthermore, the chemistry of soils analyzed in the vicinity of the dunes indicates that they are similar to the dune material. Altogether these observations suggest that the olivine content determined by X-ray diffraction of the <150 μm grain-size sample should be considered as a lower limit for the Bagnold dunes.« less

  16. Decadal application of WRF/chem for regional air quality and climate modeling over the U.S. under the representative concentration pathways scenarios. Part 2: Current vs. future simulations

    NASA Astrophysics Data System (ADS)

    Yahya, Khairunnisa; Campbell, Patrick; Zhang, Yang

    2017-03-01

    Following a comprehensive model evaluation, this Part II paper presents projected changes in future (2046-2055) climate, air quality, and their interactions under the RCP4.5 and RCP8.5 scenarios using the Weather, Research and Forecasting model with Chemistry (WRF/Chem). In general, both WRF/Chem RCP4.5 and RCP8.5 simulations predict similar increases on average (∼2 °C) for 2-m temperature (T2) but different spatial distributions of the projected changes in T2, 2-m relative humidity, 10-m wind speed, precipitation, and planetary boundary layer height, due to differences in the spatial distributions of projected emissions, and their feedbacks into climate. Future O3 mixing ratios will decrease for most parts of the U.S. under the RCP4.5 scenario but increase for all areas under the RCP8.5 scenario due to higher projected temperature, greenhouse gas concentrations and biogenic volatile organic compounds (VOC) emissions, higher O3 values for boundary conditions, and disbenefit of NOx reduction and decreased NO titration over VOC-limited O3 chemistry regions. Future PM2.5 concentrations will decrease for both RCP4.5 and RCP8.5 scenarios with different trends in projected concentrations of individual PM species. Total cloud amounts decrease under both scenarios in the future due to decreases in PM and cloud droplet number concentration thus increased radiation. Those results illustrate the impacts of carbon policies with different degrees of emission reductions on future climate and air quality. The WRF/Chem and WRF simulations show different spatial patterns for projected changes in T2 for future decade, indicating different impacts of prognostic and prescribed gas/aerosol concentrations, respectively, on climate change.

  17. Comparison of CAM-Chem with Trace Gas Measurements from Airborne Field Campaigns from 2009-2016.

    NASA Astrophysics Data System (ADS)

    Schauffler, S.; Atlas, E. L.; Kinnison, D. E.; Lamarque, J. F.; Saiz-Lopez, A.; Navarro, M. A.; Donets, V.; Blake, D. R.; Blake, N. J.

    2016-12-01

    Trace gas measurements collected during seven field campaigns, two with multiple deployments, will be compared with the NCAR CAM-Chem model to evaluate the model performance over multiple years. The campaigns include HIPPO (2009-2011) pole to pole observations in the Pacific on the NSF/NCAR GV over multiple seasons; SEAC4RS (Aug./Sept., 2013) in the central and southern U.S. and western Gulf of Mexico on the NASA ER-2 and DC8; ATTREX (2011-2015) on the NASA Global Hawk over multiple seasons and locations; CONTRAST (Jan/Feb, 2014) in the western Pacific on the NSF/NCAR GV; VIRGAS (Oct., 2015) in the south central US and western Gulf of Mexico on the NASA WB-57; ORCAS (Jan/Feb, 2016) over the southern ocean on the NSF/NCAR GV; and POSIDON (Oct, 2016) in the western Pacific on the NASA WB-57. We will focus on along the flight tracks comparisons with the model and will also examine comparisons of vertical distributions and various tracer-tracer correlations.

  18. The EnVision++ system: a new immunohistochemical method for diagnostics and research. Critical comparison with the APAAP, ChemMate, CSA, LABC, and SABC techniques.

    PubMed Central

    Sabattini, E; Bisgaard, K; Ascani, S; Poggi, S; Piccioli, M; Ceccarelli, C; Pieri, F; Fraternali-Orcioni, G; Pileri, S A

    1998-01-01

    AIM: To assess a newly developed immunohistochemical detection system, the EnVision++. METHODS: A large series of differently processed normal and pathological samples and 53 relevant monoclonal antibodies were chosen. A chessboard titration assay was used to compare the results provided by the EnVision++ system with those of the APAAP, CSA, LSAB, SABC, and ChemMate methods, when applied either manually or in a TechMate 500 immunostainer. RESULTS: With the vast majority of the antibodies, EnVision++ allowed two- to fivefold higher dilutions than the APAAP, LSAB, SABC, and ChemMate techniques, the staining intensity and percentage of expected positive cells being the same. With some critical antibodies (such as the anti-CD5), it turned out to be superior in that it achieved consistently reproducible results with differently fixed or overfixed samples. Only the CSA method, which includes tyramide based enhancement, allowed the same dilutions as the EnVision++ system, and in one instance (with the anti-cyclin D1 antibody) represented the gold standard. CONCLUSIONS: The EnVision++ is an easy to use system, which avoids the possibility of disturbing endogenous biotin and lowers the cost per test by increasing the dilutions of the primary antibodies. Being a two step procedure, it reduces both the assay time and the workload. Images PMID:9797726

  19. Microwave discharge electrodeless lamps (MDEL). III. A novel tungsten-triggered MDEL device emitting VUV and UVC radiation for use in wastewater treatment.

    PubMed

    Horikoshi, Satoshi; Miura, Takashi; Kajitani, Masatsugu; Serpone, Nick

    2008-03-01

    Exposure to low doses of the xenoestrogen bisphenol A (BPA) and to the hormonal 2,4-dichlorophenoxyacetic acid (2,4-D) herbicide, an environmental endocrine disruptor, can have serious health consequences such as the induction of mammary gland ductal hyperplasias and carcinoma (LaChapelle et al., Reprod. Toxicol., 2007, 23, 20; Murray et al., Reprod. Toxicol., 2007, 23, 383). To the extent that these toxins are present in wastewaters (Donald et al., Sci. Total Environ. 1999, 231, 173; Brotons et al., Environ. Health Perspect. 1994, 103, 608; Olea et al., Environ. Health Perspect. 1996, 104, 298; Biles et al., J. Agric. Food Chem. 1997, 45, 3541; Markey et al., J. Steroid Biochem. Mol. Biol., 2003, 83, 235), we examined their oxidative destruction in aqueous media by a novel light source. A tungsten-triggered microwave discharge electrodeless lamp (W-MDEL) was fabricated for possible use in wastewater treatment using vacuum UV-transparent quartz in which a tungsten trigger, also embedded in quartz, was attached to the MDEL to aid in the self-ignition of the lamp on irradiation at low microwave power levels. The quantity of mercury gas in the W-MDEL was optimized by monitoring the continuous radiation and peak intensities of the emitted light in the vacuum UV (VUV) and UVC regions. The usefulness of the W-MDEL device was assessed through the degradation of 2,4-D and BPA in air-equilibrated aqueous media and in oxygen-saturated aqueous media. Enhanced degradation of these two xenoestrogenic toxins was achieved by increasing the number of W-MDEL devices while keeping constant the microwave radiation feeding each W-MDEL lamp. This novel lamp provides an additional light source in the photooxidation of environmental contaminants without the need for a metal-oxide photocatalyst. Under our conditions, process dynamics using the W-MDEL light source are greater than with the more conventional photochemical methods that employ low-pressure Hg arc electrode lamps in synthetic

  20. Mechanisms of Hop Inhibition Include the Transmembrane Redox Reaction▿

    PubMed Central

    Behr, Jürgen; Vogel, Rudi F.

    2010-01-01

    In this work, a novel mechanistic model of hop inhibition beyond the proton ionophore action toward (beer spoiling) bacteria was developed. Investigations were performed with model systems using cyclic voltammetry for the determination of redox processes/conditions in connection with growth challenges with hop-sensitive and -resistant Lactobacillus brevis strains in the presence of oxidants. Cyclic voltammetry identified a transmembrane redox reaction of hop compounds at low pH (common in beer) and in the presence of manganese (present in millimolar levels in lactic acid bacteria). The antibacterial action of hop compounds could be extended from the described proton ionophore activity, lowering the intracellular pH, to pronounced redox reactivity, causing cellular oxidative damage. Accordingly, a correlation between the resistance of L. brevis strains to a sole oxidant to their resistance to hop could not be expected and was not detected. However, in connection with our recent study concerning hop ionophore properties and the resistance of hop-sensitive and -tolerant L. brevis strains toward proton ionophores (J. Behr and R. F. Vogel, J. Agric. Food Chem. 57:6074-6081, 2009), we suggest that both ionophore and oxidant resistance are required for survival under hop stress conditions and confirmed this correlation according to the novel mechanistic model. In consequence, the expression of several published hop resistance mechanisms involved in manganese binding/transport and intracellular redox balance, as well as that of proteins involved in oxidative stress under “highly reducing” conditions (cf. anaerobic cultivation and “antioxidative” hop compounds in the growth medium), is now comprehensible. Accordingly, hop resistance as a multifactorial dynamic property at least implies distinct resistance levels against two different mechanisms of hop inhibition, namely, proton ionophore-induced and oxidative stress-induced mechanisms. Beyond this specific model of

  1. Accuracy Quantification of the Loci-CHEM Code for Chamber Wall Heat Transfer in a GO2/GH2 Single Element Injector Model Problem

    NASA Technical Reports Server (NTRS)

    West, Jeff; Westra, Doug; Lin, Jeff; Tucker, Kevin

    2006-01-01

    A robust rocket engine combustor design and development process must include tools which can accurately predict the multi-dimensional thermal environments imposed on solid surfaces by the hot combustion products. Currently, empirical methods used in the design process are typically one dimensional and do not adequately account for the heat flux rise rate in the near-injector region of the chamber. Computational Fluid Dynamics holds promise to meet the design tool requirement, but requires accuracy quantification, or validation, before it can be confidently applied in the design process. This effort presents the beginning of such a validation process for the Loci-CHEM CFD code. The model problem examined here is a gaseous oxygen (GO2)/gaseous hydrogen (GH2) shear coaxial single element injector operating at a chamber pressure of 5.42 MPa. The GO2/GH2 propellant combination in this geometry represents one the simplest rocket model problems and is thus foundational to subsequent validation efforts for more complex injectors. Multiple steady state solutions have been produced with Loci-CHEM employing different hybrid grids and two-equation turbulence models. Iterative convergence for each solution is demonstrated via mass conservation, flow variable monitoring at discrete flow field locations as a function of solution iteration and overall residual performance. A baseline hybrid was used and then locally refined to demonstrate grid convergence. Solutions were obtained with three variations of the k-omega turbulence model.

  2. Accuracy Quantification of the Loci-CHEM Code for Chamber Wall Heat Fluxes in a G02/GH2 Single Element Injector Model Problem

    NASA Technical Reports Server (NTRS)

    West, Jeff; Westra, Doug; Lin, Jeff; Tucker, Kevin

    2006-01-01

    A robust rocket engine combustor design and development process must include tools which can accurately predict the multi-dimensional thermal environments imposed on solid surfaces by the hot combustion products. Currently, empirical methods used in the design process are typically one dimensional and do not adequately account for the heat flux rise rate in the near-injector region of the chamber. Computational Fluid Dynamics holds promise to meet the design tool requirement, but requires accuracy quantification, or validation, before it can be confidently applied in the design process. This effort presents the beginning of such a validation process for the Loci- CHEM CPD code. The model problem examined here is a gaseous oxygen (GO2)/gaseous hydrogen (GH2) shear coaxial single element injector operating at a chamber pressure of 5.42 MPa. The GO2/GH2 propellant combination in this geometry represents one the simplest rocket model problems and is thus foundational to subsequent validation efforts for more complex injectors. Multiple steady state solutions have been produced with Loci-CHEM employing different hybrid grids and two-equation turbulence models. Iterative convergence for each solution is demonstrated via mass conservation, flow variable monitoring at discrete flow field locations as a function of solution iteration and overall residual performance. A baseline hybrid grid was used and then locally refined to demonstrate grid convergence. Solutions were also obtained with three variations of the k-omega turbulence model.

  3. Trans-Pacific transport and evolution of aerosols: Evaluation of quasi-global WRF-Chem simulation with multiple observations

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hu, Zhiyuan; Zhao, Chun; Huang, Jianping

    A fully coupled meteorology-chemistry model (WRF-Chem, the Weather Research and Forecasting model coupled with chemistry) has been configured to conduct quasi-global simulation for 5 years (2010–2014) and evaluated with multiple observation data sets for the first time. The evaluation focuses on the simulation over the trans-Pacific transport region using various reanalysis and observational data sets for meteorological fields and aerosol properties. The simulation generally captures the overall spatial and seasonal variability of satellite retrieved aerosol optical depth (AOD) and absorbing AOD (AAOD) over the Pacific that is determined by the outflow of pollutants and dust and the emissions of marine aerosols.more » The assessment of simulated extinction Ångström exponent (EAE) indicates that the model generally reproduces the variability of aerosol size distributions as seen by satellites. In addition, the vertical profile of aerosol extinction and its seasonality over the Pacific are also well simulated. The difference between the simulation and satellite retrievals can be mainly attributed to model biases in estimating marine aerosol emissions as well as the satellite sampling and retrieval uncertainties. Compared with the surface measurements over the western USA, the model reasonably simulates the observed magnitude and seasonality of dust, sulfate, and nitrate surface concentrations, but significantly underestimates the peak surface concentrations of carbonaceous aerosol likely due to model biases in the spatial and temporal variability of biomass burning emissions and secondary organic aerosol (SOA) production. A sensitivity simulation shows that the trans-Pacific transported dust, sulfate, and nitrate can make significant contribution to surface concentrations over the rural areas of the western USA, while the peaks of carbonaceous aerosol surface concentrations are dominated by the North American emissions. Both the retrievals and simulation show

  4. Trans-Pacific transport and evolution of aerosols: Evaluation of quasi-global WRF-Chem simulation with multiple observations

    DOE PAGES

    Hu, Zhiyuan; Zhao, Chun; Huang, Jianping; ...

    2016-05-10

    A fully coupled meteorology-chemistry model (WRF-Chem, the Weather Research and Forecasting model coupled with chemistry) has been configured to conduct quasi-global simulation for 5 years (2010–2014) and evaluated with multiple observation data sets for the first time. The evaluation focuses on the simulation over the trans-Pacific transport region using various reanalysis and observational data sets for meteorological fields and aerosol properties. The simulation generally captures the overall spatial and seasonal variability of satellite retrieved aerosol optical depth (AOD) and absorbing AOD (AAOD) over the Pacific that is determined by the outflow of pollutants and dust and the emissions of marine aerosols.more » The assessment of simulated extinction Ångström exponent (EAE) indicates that the model generally reproduces the variability of aerosol size distributions as seen by satellites. In addition, the vertical profile of aerosol extinction and its seasonality over the Pacific are also well simulated. The difference between the simulation and satellite retrievals can be mainly attributed to model biases in estimating marine aerosol emissions as well as the satellite sampling and retrieval uncertainties. Compared with the surface measurements over the western USA, the model reasonably simulates the observed magnitude and seasonality of dust, sulfate, and nitrate surface concentrations, but significantly underestimates the peak surface concentrations of carbonaceous aerosol likely due to model biases in the spatial and temporal variability of biomass burning emissions and secondary organic aerosol (SOA) production. A sensitivity simulation shows that the trans-Pacific transported dust, sulfate, and nitrate can make significant contribution to surface concentrations over the rural areas of the western USA, while the peaks of carbonaceous aerosol surface concentrations are dominated by the North American emissions. Both the retrievals and simulation show

  5. Trans-Pacific transport and evolution of aerosols: evaluation of quasi-global WRF-Chem simulation with multiple observations

    NASA Astrophysics Data System (ADS)

    Hu, Zhiyuan; Zhao, Chun; Huang, Jianping; Leung, L. Ruby; Qian, Yun; Yu, Hongbin; Huang, Lei; Kalashnikova, Olga V.

    2016-05-01

    A fully coupled meteorology-chemistry model (WRF-Chem, the Weather Research and Forecasting model coupled with chemistry) has been configured to conduct quasi-global simulation for 5 years (2010-2014) and evaluated with multiple observation data sets for the first time. The evaluation focuses on the simulation over the trans-Pacific transport region using various reanalysis and observational data sets for meteorological fields and aerosol properties. The simulation generally captures the overall spatial and seasonal variability of satellite retrieved aerosol optical depth (AOD) and absorbing AOD (AAOD) over the Pacific that is determined by the outflow of pollutants and dust and the emissions of marine aerosols. The assessment of simulated extinction Ångström exponent (EAE) indicates that the model generally reproduces the variability of aerosol size distributions as seen by satellites. In addition, the vertical profile of aerosol extinction and its seasonality over the Pacific are also well simulated. The difference between the simulation and satellite retrievals can be mainly attributed to model biases in estimating marine aerosol emissions as well as the satellite sampling and retrieval uncertainties. Compared with the surface measurements over the western USA, the model reasonably simulates the observed magnitude and seasonality of dust, sulfate, and nitrate surface concentrations, but significantly underestimates the peak surface concentrations of carbonaceous aerosol likely due to model biases in the spatial and temporal variability of biomass burning emissions and secondary organic aerosol (SOA) production. A sensitivity simulation shows that the trans-Pacific transported dust, sulfate, and nitrate can make significant contribution to surface concentrations over the rural areas of the western USA, while the peaks of carbonaceous aerosol surface concentrations are dominated by the North American emissions. Both the retrievals and simulation show small

  6. Comment on 'The diatomic dication CuZn{sup 2+} in the gas phase' [J. Chem. Phys. 135, 034306 (2011)

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Fiser, Jiri; Diez, Reinaldo Pis; Franzreb, Klaus

    2013-02-21

    In this Comment, the density functional theory (DFT) calculations carried out by Diez et al. [J. Chem. Phys. 135, 034306 (2011)] are revised within the framework of the coupled-cluster single double triple method. These more sophisticated calculations allow us to show that the {sup 2}{Sigma}{sup +} electronic ground state of CuZn{sup 2+}, characterized as the metastable ground state by DFT calculations, is a repulsive state instead. The {sup 2}{Delta} and {sup 2}{Pi} metastable states of CuZn{sup 2+}, on the other hand, should be responsible for the formation mechanism of the dication through the near-resonant electron transfer CuZn{sup +}+ Ar{sup +}{yields}more » CuZn{sup 2+}+ Ar reaction.« less

  7. Evaluation of WRF-CHEM Model: A case study of Air Pollution Episode in Istanbul Metropolitan

    NASA Astrophysics Data System (ADS)

    Aydınöz, Esra; Gürer, Kemal; Toros, Hüseyin

    2014-05-01

    Istanbul is the largest city in Europe with a population of about 14 million and nearly 3.2 million registered vehicles. Considering that the city is at the junction of major transportation routes on both land and sea, emissions from all motor vehicles operating in the city and those that are in transit is the major source of pollution. The natural gas is used as the major heat source and the impact of other heating sources on the pollution episodes is not clearly known. During 19-29 December 2013 İstanbul metropolitan area experienced a severe PM10 episode with average episode concentration of 127µgm-3 . The episode was associated with a high pressure system with center pressure of 1030 mb residing over Balkans and north of Black Sea and thereby influencing Istanbul. We carried out simulations using the Weather Research and Forecasting model with Chemistry (WRF-CHEM) v3.5 to examine the meteorological conditions and to produce estimates of PM10 over Istanbul for 17-31 December 2013. The three nested domains was setup using 18, 6 and 2 km horizontal grid spacing with (90x90), (115x115) and (130x130) grid points in 1st, 2nd and 3rd domains, respectively. The each domain was run using one way nesting option after preparing the results from the mother domain as an input to subsequent inner domain. 34 vertical levels were used with the lowest layer depth of 15 m above the surface and extending to 15 km at the model top. The model was configured using the model options after many tests to find optimal model parameters and was initialized using global emissions data available publicly. The local emissions database is still in works and is not available to use in the model instead of global data. The estimated PM10 concentrations were compared against the observed conditions. This work shows the first attempt of using WRF-CHEM in Turkey to estimate the pollutant concentrations instead of using other air pollution models such as WRF/CMAQ combination. At the time of

  8. Mercury and selenium accumulation in the Colorado River food web, Grand Canyon, USA

    USGS Publications Warehouse

    Walters, David M.; E.J. Rosi-Marshall,; Kennedy, Theodore A.; W.F. Cross,; C.V. Baxter,

    2015-01-01

    Mercury (Hg) and selenium (Se) biomagnify in aquatic food webs and are toxic to fish and wildlife. The authors measured Hg and Se in organic matter, invertebrates, and fishes in the Colorado River food web at sites spanning 387 river km downstream of Glen Canyon Dam (AZ, USA). Concentrations were relatively high among sites compared with other large rivers (mean wet wt for 6 fishes was 0.17–1.59 μg g–1 Hg and 1.35–2.65 μg g–1 Se), but consistent longitudinal patterns in Hg or Se concentrations relative to the dam were lacking. Mercury increased (slope = 0.147) with δ15N, a metric of trophic position, indicating biomagnification similar to that observed in other freshwater systems. Organisms regularly exceeded exposure risk thresholds for wildlife and humans (6–100% and 56–100% of samples for Hg and Se, respectfully, among risk thresholds). In the Colorado River, Grand Canyon, Hg and Se concentrations pose exposure risks for fish, wildlife, and humans, and the findings of the present study add to a growing body of evidence showing that remote ecosystems are vulnerable to long-range transport and subsequent bioaccumulation of contaminants. Management of exposure risks in Grand Canyon will remain a challenge, as sources and transport mechanisms of Hg and Se extend far beyond park boundaries. Environ Toxicol Chem2015;9999:1–10

  9. Chemo-stratigraphy in the Murray Formation Using ChemCam

    NASA Astrophysics Data System (ADS)

    Blaney, D. L.; Anderson, R. B.; Bridges, N.; Bridges, J.; Calef, F. J., III; Clegg, S. M.; Le Deit, L.; Fisk, M. R.; Forni, O.; Gasnault, O.; Kah, L. C.; Kronyak, R. E.; Lanza, N.; Lasue, J.; Mangold, N.; Maurice, S.; Milliken, R.; Ming, D. W.; Nachon, M.; Newsom, H. E.; Rapin, W.; Stack, K.; Sumner, D. Y.; Wiens, R. C.

    2015-12-01

    Curiosity has completed a detailed chemo-stratigraphy analysis at the Pahrump exposure of the Murray formation. In total >570 chemical measurements and supporting remote micro images to classify texturally were collected. Chemical trends with both stratigraphic position and with texture were evaluated. From these data emerges a complex aqueous history where sediments have interacted with fluids with variable chemistry in distinct episodes. The ChemCam data collected at the nearby "Garden City" (GC) vein complex provides constraints on the chemical evolution of the Pahrump. GC is thought be stratigraphically above the Pahrump outcrop. Fluids producing the veins likely also migrated through the Pahrump sediments. Multiple episodes of fluids are evident at GC, forming distinct Ca sulfate, F-rich, enhanced MgO, and FeO-rich veins. These different fluid chemistries could be the result of distinct fluids migrating through the section from a distance with a pre-established chemical signature, fluids locally evolved from water rock interactions, or both. Texturally rocks have been classified into two distinct categories: fine grained or as cross-bedded sandstones. The sandstones have significantly lower SiO2, Al2O3, and K2O and higher FeO, and CaO. Fine grained rocks have further been sub-classified as resistant and recessive with other textural features such as laminations and pits noted.The strongest chemical trend in the fine-grained sandstones shows enhancements in MgO and FeO in erosion-resistant materials compared to fine grained recessive units, suggesting that increased abundance of Mg- and/or iron-rich cements may provide additional strength. The MgO and FeO variations with texture are independent of stratigraphic locations (e.g resistant material at both the bottom and top of the outcrop both are enhanced in MgO and FeO). The presence of the GC MgO and FeO rich veins provides additional evidence for fluids rich in these elements were present in the outcrop. Other

  10. Risk of POP mixtures on the Arctic food chain.

    PubMed

    Villa, Sara; Migliorati, Sonia; Monti, Gianna Serafina; Holoubek, Ivan; Vighi, Marco

    2017-05-01

    The exposure of the Arctic ecosystem to persistent organic pollutants (POPs) was assessed through a review of literature data. Concentrations of 19 chemicals or congeneric groups were estimated for the highest levels of the Arctic food chain (Arctic cod, ringed seals, and polar bears). The ecotoxicological risk for seals, bears, and bear cubs was estimated by applying the concentration addition (CA) concept. The risk of POP mixtures was very low in seals. By contrast, the risk was 2 orders of magnitude higher than the risk threshold for adult polar bears and even more (3 orders of magnitude above the threshold) for bear cubs fed with contaminated milk. Based on the temporal trends available for many of the chemicals, the temporal trend of the mixture risk for bear cubs was calculated. Relative to the 1980s, a decrease in risk from the POP mixture is evident, mainly because of international control measures. However, the composition of the mixture substantially changes, and the contribution of new POPs (particularly perfluorooctane sulfonate) increases. These results support the effectiveness of control measures, such as those promulgated in the Stockholm Convention, as well as the urgent need for their implementation for new and emerging POPs. Environ Toxicol Chem 2017;36:1181-1192. © 2017 SETAC. © 2017 SETAC.

  11. Use, Assessment, and Improvement of the Loci-CHEM CFD Code for Simulation of Combustion in a Single Element GO2/GH2 Injector and Chamber

    NASA Technical Reports Server (NTRS)

    Westra, Douglas G.; Lin, Jeff; West, Jeff; Tucker, Kevin

    2006-01-01

    This document is a viewgraph presentation of a paper that documents a continuing effort at Marshall Space Flight Center (MSFC) to use, assess, and continually improve CFD codes to the point of material utility in the design of rocket engine combustion devices. This paper describes how the code is presently being used to simulate combustion in a single element combustion chamber with shear coaxial injectors using gaseous oxygen and gaseous hydrogen propellants. The ultimate purpose of the efforts documented is to assess and further improve the Loci-CHEM code and the implementation of it. Single element shear coaxial injectors were tested as part of the Staged Combustion Injector Technology (SCIT) program, where detailed chamber wall heat fluxes were measured. Data was taken over a range of chamber pressures for propellants injected at both ambient and elevated temperatures. Several test cases are simulated as part of the effort to demonstrate use of the Loci-CHEM CFD code and to enable us to make improvements in the code as needed. The simulations presented also include a grid independence study on hybrid grids. Several two-equation eddy viscosity low Reynolds number turbulence models are also evaluated as part of the study. All calculations are presented with a comparison to the experimental data. Weaknesses of the code relative to test data are discussed and continuing efforts to improve the code are presented.

  12. A new chemistry option in WRF/Chem v. 3.4 for the simulation of direct and indirect aerosol effects using VBS: evaluation against IMPACT-EUCAARI data

    NASA Astrophysics Data System (ADS)

    Tuccella, P.; Curci, G.; Grell, G. A.; Visconti, G.; Crumeroylle, S.; Schwarzenboeck, A.; Mensah, A. A.

    2015-02-01

    A parameterization for secondary organic aerosol (SOA) production based on the volatility basis set (VBS) approach has been coupled with microphysics and radiative scheme in WRF/Chem model. The new chemistry option called "RACM/MADE/VBS" was evaluated on a cloud resolving scale against ground-based and aircraft measurements collected during the IMPACT-EUCAARI campaign, and complemented with satellite data from MODIS. The day-to-day variability and the diurnal cycle of ozone (O3) and nitrogen oxides (NOx) at the surface is captured by the model. Surface aerosol mass of sulphate (SO4), nitrate (NO3), ammonium (NH4), and organic matter (OM) is simulated with a correlation larger than 0.55. WRF/Chem captures the vertical profile of the aerosol mass in both the planetary boundary layer (PBL) and free troposphere (FT) as a function of the synoptic condition, but the model does not capture the full range of the measured concentrations. Predicted OM concentration is at the lower end of the observed mass. The bias may be attributable to the missing aqueous chemistry processes of organic compounds, the uncertainties in meteorological fields, the assumption on the deposition velocity of condensable organic vapours, and the uncertainties in the anthropogenic emissions of primary organic carbon. Aerosol particle number concentration (condensation nuclei, CN) is overestimated by a factor 1.4 and 1.7 within PBL and FT, respectively. Model bias is most likely attributable to the uncertainties of primary particle emissions (mostly in the PBL) and to the nucleation rate. The overestimation of simulated cloud condensation nuclei (CCN) is more contained with respect to that of CN. The CCN efficiency, which is a measure of the ability of aerosol particles to nucleate cloud droplets, is underestimated by a factor of 1.5 and 3.8 in the PBL and FT, respectively. The comparison with MODIS data shows that the model overestimates the aerosol optical thickness (AOT). The domain averages (for

  13. Constraints on iron sulfate and iron oxide mineralogy from ChemCam visible/near-infrared reflectance spectroscopy of Mt. Sharp basal units, Gale Crater, Mars

    DOE PAGES

    Johnson, Jeffrey R.; Bell, James F.; Bender, Steve; ...

    2016-07-01

    Relative reflectace point spectra (400–840 nm) were acquired by the Chemistry and Camera (ChemCam) instrument on the Mars Science Laboratory (MSL) rover Curiosity in passive mode (no laser) of drill tailings and broken rock fragments near the rover as it entered the lower reaches of Mt. Sharp and of landforms at distances of 2–8 km. Freshly disturbed surfaces are less subject to the spectral masking effects of dust, and revealed spectral features consistent with the presence of iron oxides and ferric sulfates. Here, we present the first detection on Mars of a ~433 nm absorption band consistent with small abundancesmore » of ferric sulfates, corroborated by jarosite detections by the Chemistry and Mineralogy (CheMin) X-ray diffraction instrument in the Mojave, Telegraph Peak, and Confidence Hills drilled samples. The disturbed materials near the Bonanza King region also exhibited strong 433 nm bands and negative near-infrared spectral slopes consistent with jarosite. ChemCam passive spectra of the Confidence Hills and Mojave drill tailings showed features suggestive of the crystalline hematite identified by CheMin analyses. The Windjana drill sample tailings exhibited flat, low relative reflectance spectra, explained by the occurrence of magnetite detected by CheMin. Passive spectra of Bonanza King were similar, suggesting the presence of spectrally dark and neutral minerals such as magnetite. Long-distance spectra of the “Hematite Ridge” feature (3–5 km from the rover) exhibited features consistent with crystalline hematite. The Bagnold dune field north of the Hematite Ridge area exhibited low relative reflectance and near-infrared features indicative of basaltic materials (olivine, pyroxene). Light-toned layers south of Hematite Ridge lacked distinct spectral features in the 400–840 nm region, and may represent portions of nearby clay minerals and sulfates mapped with orbital near-infrared observations. The presence of ferric sulfates such as

  14. Constraints on iron sulfate and iron oxide mineralogy from ChemCam visible/near-infrared reflectance spectroscopy of Mt. Sharp basal units, Gale Crater, Mars

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Johnson, Jeffrey R.; Bell, James F.; Bender, Steve

    Relative reflectace point spectra (400–840 nm) were acquired by the Chemistry and Camera (ChemCam) instrument on the Mars Science Laboratory (MSL) rover Curiosity in passive mode (no laser) of drill tailings and broken rock fragments near the rover as it entered the lower reaches of Mt. Sharp and of landforms at distances of 2–8 km. Freshly disturbed surfaces are less subject to the spectral masking effects of dust, and revealed spectral features consistent with the presence of iron oxides and ferric sulfates. Here, we present the first detection on Mars of a ~433 nm absorption band consistent with small abundancesmore » of ferric sulfates, corroborated by jarosite detections by the Chemistry and Mineralogy (CheMin) X-ray diffraction instrument in the Mojave, Telegraph Peak, and Confidence Hills drilled samples. The disturbed materials near the Bonanza King region also exhibited strong 433 nm bands and negative near-infrared spectral slopes consistent with jarosite. ChemCam passive spectra of the Confidence Hills and Mojave drill tailings showed features suggestive of the crystalline hematite identified by CheMin analyses. The Windjana drill sample tailings exhibited flat, low relative reflectance spectra, explained by the occurrence of magnetite detected by CheMin. Passive spectra of Bonanza King were similar, suggesting the presence of spectrally dark and neutral minerals such as magnetite. Long-distance spectra of the “Hematite Ridge” feature (3–5 km from the rover) exhibited features consistent with crystalline hematite. The Bagnold dune field north of the Hematite Ridge area exhibited low relative reflectance and near-infrared features indicative of basaltic materials (olivine, pyroxene). Light-toned layers south of Hematite Ridge lacked distinct spectral features in the 400–840 nm region, and may represent portions of nearby clay minerals and sulfates mapped with orbital near-infrared observations. The presence of ferric sulfates such as

  15. Quantifying errors in surface ozone predictions associated with clouds over the CONUS: a WRF-Chem modeling study using satellite cloud retrievals

    NASA Astrophysics Data System (ADS)

    Ryu, Young-Hee; Hodzic, Alma; Barre, Jerome; Descombes, Gael; Minnis, Patrick

    2018-05-01

    Clouds play a key role in radiation and hence O3 photochemistry by modulating photolysis rates and light-dependent emissions of biogenic volatile organic compounds (BVOCs). It is not well known, however, how much error in O3 predictions can be directly attributed to error in cloud predictions. This study applies the Weather Research and Forecasting with Chemistry (WRF-Chem) model at 12 km horizontal resolution with the Morrison microphysics and Grell 3-D cumulus parameterization to quantify uncertainties in summertime surface O3 predictions associated with cloudiness over the contiguous United States (CONUS). All model simulations are driven by reanalysis of atmospheric data and reinitialized every 2 days. In sensitivity simulations, cloud fields used for photochemistry are corrected based on satellite cloud retrievals. The results show that WRF-Chem predicts about 55 % of clouds in the right locations and generally underpredicts cloud optical depths. These errors in cloud predictions can lead to up to 60 ppb of overestimation in hourly surface O3 concentrations on some days. The average difference in summertime surface O3 concentrations derived from the modeled clouds and satellite clouds ranges from 1 to 5 ppb for maximum daily 8 h average O3 (MDA8 O3) over the CONUS. This represents up to ˜ 40 % of the total MDA8 O3 bias under cloudy conditions in the tested model version. Surface O3 concentrations are sensitive to cloud errors mainly through the calculation of photolysis rates (for ˜ 80 %), and to a lesser extent to light-dependent BVOC emissions. The sensitivity of surface O3 concentrations to satellite-based cloud corrections is about 2 times larger in VOC-limited than NOx-limited regimes. Our results suggest that the benefits of accurate predictions of cloudiness would be significant in VOC-limited regions, which are typical of urban areas.

  16. Assessing the Impact of Oil and Natural Gas Activities on Regional Air Quality in the Colorado Northern Front Range using WRF-Chem

    NASA Astrophysics Data System (ADS)

    Abdioskouei, M.; Carmichael, G. R.

    2017-12-01

    Recent increases in the Natural Gas (NG) production through hydraulic fracturing have questioned the climate benefit of switching from coal-fired to natural gas-fired power plants. Higher than expected levels of methane, VOCs, and NOx have been observed in areas close to oil and NG (OnG) operation facilities. High uncertainty in the OnG emission inventories and methane budget challenge the assessment of OnG impact on air quality and climate and consequently development of effective mitigation policies and control regulations. In this work, we focus on reducing the uncertainties around the OnG emissions by using high resolution (4x4 km2) WRF-Chem simulations coupled with detailed observation from the Front Range Air Pollution and Photochemistry Éxperiment (FRAPPÉ 2014) field campaign. First, we identified the optimal WRF-Chem configurations in the NFR area. We compared the performance of local and non-local Planetary Boundary Layer (PBL) schemes in predicting the PBL height and vertical mixing in the domain. We evaluated the impact of different meteorological and chemical initial and boundary conditions on the model performance. Next, simulations based on optimal configurations were used to assess the performance of the emission inventory (NEI-2011v2). To evaluate the impact of OnG emission on regional air quality and performance of NEI-2011 we tested the sensitivity of the model to the OnG emission. Comparison between simulated values and ground-based and airborne measurements shows a low bias of OnG emission in NEI-2011. Finally, inverse modeling techniques based on emission sensitivity simulations are being used to optimal scaling the OnG emission from the NEI-2011.

  17. ChemMaps: Towards an approach for visualizing the chemical space based on adaptive satellite compounds

    PubMed Central

    Naveja, J. Jesús; Medina-Franco, José L.

    2017-01-01

    We present a novel approach called ChemMaps for visualizing chemical space based on the similarity matrix of compound datasets generated with molecular fingerprints’ similarity. The method uses a ‘satellites’ approach, where satellites are, in principle, molecules whose similarity to the rest of the molecules in the database provides sufficient information for generating a visualization of the chemical space. Such an approach could help make chemical space visualizations more efficient. We hereby describe a proof-of-principle application of the method to various databases that have different diversity measures. Unsurprisingly, we found the method works better with databases that have low 2D diversity. 3D diversity played a secondary role, although it seems to be more relevant as 2D diversity increases. For less diverse datasets, taking as few as 25% satellites seems to be sufficient for a fair depiction of the chemical space. We propose to iteratively increase the satellites number by a factor of 5% relative to the whole database, and stop when the new and the prior chemical space correlate highly. This Research Note represents a first exploratory step, prior to the full application of this method for several datasets. PMID:28794856

  18. ChemMaps: Towards an approach for visualizing the chemical space based on adaptive satellite compounds.

    PubMed

    Naveja, J Jesús; Medina-Franco, José L

    2017-01-01

    We present a novel approach called ChemMaps for visualizing chemical space based on the similarity matrix of compound datasets generated with molecular fingerprints' similarity. The method uses a 'satellites' approach, where satellites are, in principle, molecules whose similarity to the rest of the molecules in the database provides sufficient information for generating a visualization of the chemical space. Such an approach could help make chemical space visualizations more efficient. We hereby describe a proof-of-principle application of the method to various databases that have different diversity measures. Unsurprisingly, we found the method works better with databases that have low 2D diversity. 3D diversity played a secondary role, although it seems to be more relevant as 2D diversity increases. For less diverse datasets, taking as few as 25% satellites seems to be sufficient for a fair depiction of the chemical space. We propose to iteratively increase the satellites number by a factor of 5% relative to the whole database, and stop when the new and the prior chemical space correlate highly. This Research Note represents a first exploratory step, prior to the full application of this method for several datasets.

  19. Food retailing and food service.

    PubMed

    Capps, Oral; Park, John L

    2003-07-01

    The food retailing and food service sector is not only an important component of the food marketing channel but is also vital to the United States economy, accounting for more than 7% of the United States gross domestic product in 2001. The business of food retailing and food service is undergoing salient change. The authors argue that the singular force driving this change is the consumer. To understand the linkages in the food marketing channel, this article provides information on the farm-to-retail price spread and the economic forces that influence their magnitude. Examples are given of farm-to-retail price spreads for red meat and dairy industries. In addition, the economics behind the provision of retail services and the growth of the food service industry are discussed. Further, the authors demonstrate that the structure of the food market channel is consumer driven, and present three characteristics of convenience (preparation, delivery, and service) and identify four food distribution channels in terms of convenience (complete convenience, traditional food service, consumer direct, and traditional retail).

  20. Do television food advertisements portray advertised foods in a 'healthy' food context?

    PubMed

    Adams, Jean; Tyrrell, Rachel; White, Martin

    2011-03-01

    Exposure to food promotion influences food preferences and diet. As food advertisements tend to promote 'less healthy' products, food advertising probably plays some role in the 'obesity epidemic'. Amid calls for increased regulation, food manufacturers are beginning to engage in a variety of health-promoting marketing initiatives. Positioning products in the context of a 'healthy', balanced diet in television advertisements is one such initiative. We explored whether the wider food context in which foods are advertised on television are 'healthier' than the advertised foods themselves. All foods shown in food advertisements broadcast during 1 week on one commercial UK channel were identified and classified as 'primary' (i.e. the focus of advertisements) or 'incidental'. The nutritional content of all foods was determined and that of primary and incidental foods were compared. Almost two-thirds of food advertisements did not include any incidental foods. When a wider food context was present, this tended to be 'healthier' than the primary foods that were the focus of food advertisements - particularly in terms of the food groups represented. It is not yet clear what effect this may have on consumers' perceptions and behaviour, and whether or not this practice should be encouraged or discouraged from a public health perspective.

  1. Seasonal and interannual variability in wetland methane emissions simulated by CLM4Me' and CAM-chem and comparisons to observations of concentrations

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Meng, L.; Paudel, R.; Hess, P. G. M.

    Understanding the temporal and spatial variation of wetland methane emissions is essential to the estimation of the global methane budget. Our goal for this study is three-fold: (i) to evaluate the wetland methane fluxes simulated in two versions of the Community Land Model, the Carbon-Nitrogen (CN; i.e., CLM4.0) and the Biogeochemistry (BGC; i.e., CLM4.5) versions using the methane emission model CLM4Me' so as to determine the sensitivity of the emissions to the underlying carbon model; (ii) to compare the simulated atmospheric methane concentrations to observations, including latitudinal gradients and interannual variability so as to determine the extent to which themore » atmospheric observations constrain the emissions; (iii) to understand the drivers of seasonal and interannual variability in atmospheric methane concentrations. Simulations of the transport and removal of methane use the Community Atmosphere Model with chemistry (CAM-chem) model in conjunction with CLM4Me' methane emissions from both CN and BGC simulations and other methane emission sources from literature. In each case we compare model-simulated atmospheric methane concentration with observations. In addition, we simulate the atmospheric concentrations based on the TransCom wetland and rice paddy emissions derived from a different terrestrial ecosystem model, Vegetation Integrative Simulator for Trace gases (VISIT). Our analysis indicates CN wetland methane emissions are higher in the tropics and lower at high latitudes than emissions from BGC. In CN, methane emissions decrease from 1993 to 2004 while this trend does not appear in the BGC version. In the CN version, methane emission variations follow satellite-derived inundation wetlands closely. However, they are dissimilar in BGC due to its different carbon cycle. CAM-chem simulations with CLM4Me' methane emissions suggest that both prescribed anthropogenic and predicted wetlands methane emissions contribute substantially to seasonal and

  2. Seasonal and interannual variability in wetland methane emissions simulated by CLM4Me' and CAM-chem and comparisons to observations of concentrations

    DOE PAGES

    Meng, L.; Paudel, R.; Hess, P. G. M.; ...

    2015-07-03

    Understanding the temporal and spatial variation of wetland methane emissions is essential to the estimation of the global methane budget. Our goal for this study is three-fold: (i) to evaluate the wetland methane fluxes simulated in two versions of the Community Land Model, the Carbon-Nitrogen (CN; i.e., CLM4.0) and the Biogeochemistry (BGC; i.e., CLM4.5) versions using the methane emission model CLM4Me' so as to determine the sensitivity of the emissions to the underlying carbon model; (ii) to compare the simulated atmospheric methane concentrations to observations, including latitudinal gradients and interannual variability so as to determine the extent to which themore » atmospheric observations constrain the emissions; (iii) to understand the drivers of seasonal and interannual variability in atmospheric methane concentrations. Simulations of the transport and removal of methane use the Community Atmosphere Model with chemistry (CAM-chem) model in conjunction with CLM4Me' methane emissions from both CN and BGC simulations and other methane emission sources from literature. In each case we compare model-simulated atmospheric methane concentration with observations. In addition, we simulate the atmospheric concentrations based on the TransCom wetland and rice paddy emissions derived from a different terrestrial ecosystem model, Vegetation Integrative Simulator for Trace gases (VISIT). Our analysis indicates CN wetland methane emissions are higher in the tropics and lower at high latitudes than emissions from BGC. In CN, methane emissions decrease from 1993 to 2004 while this trend does not appear in the BGC version. In the CN version, methane emission variations follow satellite-derived inundation wetlands closely. However, they are dissimilar in BGC due to its different carbon cycle. CAM-chem simulations with CLM4Me' methane emissions suggest that both prescribed anthropogenic and predicted wetlands methane emissions contribute substantially to seasonal and

  3. [Food allergy or food intolerance?].

    PubMed

    Maître, S; Maniu, C-M; Buss, G; Maillard, M H; Spertini, F; Ribi, C

    2014-04-16

    Adverse food reactions can be classified into two main categories depending on wether an immune mechanism is involved or not. The first category includes immune mediated reactions like IgE mediated food allergy, eosinophilic oesophagitis, food protein-induced enterocolitis syndrome and celiac disease. The second category implies non-immune mediated adverse food reactions, also called food intolerances. Intoxications, pharmacologic reactions, metabolic reactions, physiologic, psychologic or reactions with an unknown mechanism belong to this category. We present a classification of adverse food reactions based on the pathophysiologic mechanism that can be useful for both diagnostic approach and management.

  4. Analysis of the WRF-Chem simulations contributing to the AQMEII-Phase II exercise with respect to aerosol impact on precipitation

    NASA Astrophysics Data System (ADS)

    Werhahn, Johannes; Balzarini, Allessandra; Baró, Roccio; Curci, Gabriele; Forkel, Renate; Hirtl, Marcus; Honzak, Luka; Jiménez-Guerrero, Pedro; Langer, Matthias; Lorenz, Christof; Pérez, Juan L.; Pirovano, Guido; San José, Roberto; Tuccella, Paolo; Žabkar, Rahela

    2014-05-01

    Simulated feedback effects between aerosol concentrations and meteorological variables and on pollutant distributions are expected to depend on model configuration and the meteorological situation. In order to quantity these effects the second phase of the AQMEII (Air Quality Model Evaluation International Initiative; http://aqmeii.jrc.ec.europa.eu/) model inter-comparison exercise focused on online coupled meteorology-chemistry models. Among others, seven of the participating groups contributed simulations with WRF-Chem (Grell et al., 2005) for Europe. According to the common simulation strategy for AQMEII phase 2, the entire year 2010 was simulated as a sequence of 2-day time slices. For better comparability, the seven groups using WRF-Chem applied the same grid spacing of 23 km and shared common processing of initial and boundary conditions as well as anthropogenic and fire emissions. The simulations differ by the chosen chemistry option, aerosol module, cloud microphysics, and by the degree of aerosol-meteorology feedback that was considered. Results from this small ensemble are analyzed with respect to the effect of the different degrees of aerosol-meteorology feedback, i.e. no aerosol feedback, direct aerosol effect, and direct plus indirect aerosol effect, on large scale precipitation. Simulated precipitation fields were compared against daily precipitation observations as given by E-OBS 25 km resolution gridded dataset from the EU-FP6 project ENSEMBLES (http://ensembles-eu.metoffice.com) and the data providers in the ECA&D project (http://www.ecad.eu). As expected, a first analysis confirms that the average impact of aerosol feedback is only very small on the considered spatial and temporal scale, i.e. due to the fact that initial meteorological conditions were taken every 3rd day from a one day non-feedback spin-up run. However, the analysis of the correlations between simulation and observations for the first and the second day indicates for some

  5. Air quality modelling over the Eastern Mediterranean using the WRF/Chem model: Comparison of gas-phase chemistry and aerosol mechanisms

    NASA Astrophysics Data System (ADS)

    Georgiou, George K.; Christoudias, Theodoros; Proestos, Yiannis; Kushta, Jonilda; Hadjinicolaou, Panos; Lelieveld, Jos

    2017-04-01

    A comprehensive analysis of the performance of three coupled gas-phase chemistry and aerosol mechanisms included in the WRF/Chem model has been performed over the Eastern Mediterranean focusing on Cyprus during the CYPHEX campaign in 2014, using high temporal and spatial resolution. The model performance was evaluated by comparing calculations to measurements of gas phase species (O3, CO, NOx, SO2) and aerosols (PM10, PM2.5) from 13 ground stations. Initial results indicate that the calculated day-to-day and diurnal variations of the aforementioned species show good agreement with observations. The model was set up with three nested grids, downscaling to 4km over Cyprus. The meteorological boundary conditions were updated every 3 hours throughout the simulation using the Global Forecast System (GFS), while chemical boundary conditions were updated every 6 hours using the MOZART global chemical transport model. Biogenic emissions were calculated online by the the Model of Emissions of Gases and Aerosols from Nature version 2.1 (MEGAN2.1). Anthropogenic emissions were based on the EDGAR HTAP v2 global emission inventory, provided on a horizontal grid resolution of 0.1o × 0.1o. Three simulations were performed employing different chemistry and aerosol mechanisms; i) RADM2 chemical mechanism and MADE/SORGAM aerosols, ii) CBMZ chemical mechanism and MOSAIC aerosols, iii) MOZART chemical mechanism and MOSAIC aerosols. Results show that the WRF/Chem model satisfactorily estimates the trace gases relative concentrations at the background sites but not at the urban and traffic sites, while some differences appear between the simulated concentrations by the three mechanisms. The resulting discrepancies between the model outcome and measurements, especially at the urban and traffic sites, suggest that a higher resolution anthropogenic emission inventory might help improve fine resolution, regional air quality modelling. Differences in the simulated concentrations by the

  6. Potential sources of nitrous acid (HONO) and their impacts on ozone: A WRF-Chem study in a polluted subtropical region

    NASA Astrophysics Data System (ADS)

    Zhang, Li; Wang, Tao; Zhang, Qiang; Zheng, Junyu; Xu, Zheng; Lv, Mengyao

    2016-04-01

    Current chemical transport models commonly undersimulate the atmospheric concentration of nitrous acid (HONO), which plays an important role in atmospheric chemistry, due to the lack or inappropriate representations of some sources in the models. In the present study, we parameterized up-to-date HONO sources into a state-of-the-art three-dimensional chemical transport model (Weather Research and Forecasting model coupled with Chemistry: WRF-Chem). These sources included (1) heterogeneous reactions on ground surfaces with the photoenhanced effect on HONO production, (2) photoenhanced reactions on aerosol surfaces, (3) direct vehicle and vessel emissions, (4) potential conversion of NO2 at the ocean surface, and (5) emissions from soil bacteria. The revised WRF-Chem was applied to explore the sources of the high HONO concentrations (0.45-2.71 ppb) observed at a suburban site located within complex land types (with artificial land covers, ocean, and forests) in Hong Kong. With the addition of these sources, the revised model substantially reproduced the observed HONO levels. The heterogeneous conversions of NO2 on ground surfaces dominated HONO sources contributing about 42% to the observed HONO mixing ratios, with emissions from soil bacterial contributing around 29%, followed by the oceanic source (~9%), photochemical formation via NO and OH (~6%), conversion on aerosol surfaces (~3%), and traffic emissions (~2%). The results suggest that HONO sources in suburban areas could be more complex and diverse than those in urban or rural areas and that the bacterial and/or ocean processes need to be considered in HONO production in forested and/or coastal areas. Sensitivity tests showed that the simulated HONO was sensitive to the uptake coefficient of NO2 on the surfaces. Incorporation of the aforementioned HONO sources significantly improved the simulations of ozone, resulting in increases of ground-level ozone concentrations by 6-12% over urban areas in Hong Kong and

  7. Hybrid Food Preservation Program Improves Food Preservation and Food Safety Knowledge

    ERIC Educational Resources Information Center

    Francis, Sarah L.

    2014-01-01

    The growing trend in home food preservation raises concerns about whether the resulting food products will be safe to eat. The increased public demand for food preservation information led to the development of the comprehensive food preservation program, Preserve the Taste of Summer (PTTS). PTTS is a comprehensive hybrid food preservation program…

  8. Part I: Reverse-docking studies of a squaramide-catalyzed conjugate addition of a diketone to a nitro-olefin Part II: The development of ChemSort: an education game for organic chemistry

    NASA Astrophysics Data System (ADS)

    Granger, Jenna Christine

    Part 1: Reverse-docking studies of a squaramide-catalyzed conjugate addition of a diketone to a nitro-olefin. Asymmetric organocatalysis, the catalysis of asymmetric reactions by small organic molecules, is a rapidly growing field within organic synthesis. The ability to rationally design organocatalysts is therefore of increasing interest to organic chemists. Computational chemistry is quickly proving to be an extremely successful method for understanding and predicting the roles of organocatalysts, and therefore is certain to be of use in the rational design of such catalysts. A methodology for reverse-docking flexible organocatalysts to rigid transition state models of asymmetric reactions has been previously developed by the Deslongchamps group. The investigation of Rawal's squaramide-based organocatalyst for the addition of a diketone to a nitro-olefin is described, and the results of the reverse docking of Rawal's catalyst to the geometry optimized transition state models of the uncatalyzed reaction for both the R and S-product enantiomers are presented. The results of this study indicate a preference for binding of the organocatalyst to the R-enantiomer transition state model with a predicted enantiomeric excess of 99%, which is consistent with the experimental results. A plausible geometric model of the transition state for the catalyzed reaction is also presented. The success of this study demonstrates the credibility of using reverse docking methods for the rational design of asymmetric organocatalysts. Part 2: The development of ChemSort: an educational game for organic chemistry. With the advent of the millennial learner, we need to rethink traditional classroom approaches to science learning in terms of goals, approaches, and assessments. Digital simulations and games hold much promise in support of this educational shift. Although the idea of using games for education is not a new one, well-designed computer-based "serious games" are only beginning to

  9. Modeling of low-temperature plasmas generated using laser-induced breakdown spectroscopy: the ChemCam diagnostic tool on the Mars Science Laboratory Rover

    NASA Astrophysics Data System (ADS)

    Colgan, James

    2016-05-01

    We report on efforts to model the low-temperature plasmas generated using laser-induced breakdown spectroscopy (LIBS). LIBS is a minimally invasive technique that can quickly and efficiently determine the elemental composition of a target and is employed in an extremely wide range of applications due to its ease of use and fast turnaround. In particular, LIBS is the diagnostic tool used by the ChemCam instrument on the Mars Science Laboratory rover Curiosity. In this talk, we report on the use of the Los Alamos plasma modeling code ATOMIC to simulate LIBS plasmas, which are typically at temperatures of order 1 eV and electron densities of order 10 16 - 17 cm-3. At such conditions, these plasmas are usually in local-thermodynamic equilibrium (LTE) and normally contain neutral and singly ionized species only, which then requires that modeling must use accurate atomic structure data for the element under investigation. Since LIBS devices are often employed in a very wide range of applications, it is therefore desirable to have accurate data for most of the elements in the periodic table, ideally including actinides. Here, we discuss some recent applications of our modeling using ATOMIC that have explored the plasma physics aspects of LIBS generated plasmas, and in particular discuss the modeling of a plasma formed from a basalt sample used as a ChemCam standard1. We also highlight some of the more general atomic physics challenges that are encountered when attempting to model low-temperature plasmas. The Los Alamos National Laboratory is operated by Los Alamos National Security, LLC for the National Nuclear Security Administration of the U.S. Department of Energy under Contract No. DE-AC5206NA25396. Work performed in conjunction with D. P. Kilcrease, H. M. Johns, E. J. Judge, J. E. Barefield, R. C. Wiens, S. M. Clegg.

  10. Recalibration of the Mars Science Laboratory ChemCam instrument with an expanded geochemical database

    DOE PAGES

    Clegg, Samuel M.; Wiens, Roger C.; Anderson, Ryan; ...

    2016-12-24

    The ChemCam Laser-Induced Breakdown Spectroscopy (LIBS) instrument onboard the Mars Science Laboratory (MSL) rover Curiosity has obtained > 300,000 spectra of rock and soil analysis targets since landing at Gale Crater in 2012, and the spectra represent perhaps the largest publicly-available LIBS datasets. The compositions of the major elements, reported as oxides, have been re-calibrated using a laboratory LIBS instrument, Mars-like atmospheric conditions, and a much larger set of standards (408) that span a wider compositional range than previously employed. The new calibration uses a combination of partial least squares (PLS1) and Independent Component Analysis (ICA) algorithms, together with amore » calibration transfer matrix to minimize differences between the conditions under which the standards were analyzed in the laboratory and the conditions on Mars. While the previous model provided good results in the compositional range near the average Mars surface composition, the new model fits the extreme compositions far better. Examples are given for plagioclase feldspars, where silicon was previously significantly over-estimated, and for calcium-sulfate veins, where silicon compositions near zero were inaccurate. Here, the uncertainties of major element abundances are described as a function of the abundances, and are overall significantly lower than the previous model, enabling important new geochemical interpretations of the data.« less

  11. Recalibration of the Mars Science Laboratory ChemCam instrument with an expanded geochemical database

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Clegg, Samuel M.; Wiens, Roger C.; Anderson, Ryan

    The ChemCam Laser-Induced Breakdown Spectroscopy (LIBS) instrument onboard the Mars Science Laboratory (MSL) rover Curiosity has obtained > 300,000 spectra of rock and soil analysis targets since landing at Gale Crater in 2012, and the spectra represent perhaps the largest publicly-available LIBS datasets. The compositions of the major elements, reported as oxides, have been re-calibrated using a laboratory LIBS instrument, Mars-like atmospheric conditions, and a much larger set of standards (408) that span a wider compositional range than previously employed. The new calibration uses a combination of partial least squares (PLS1) and Independent Component Analysis (ICA) algorithms, together with amore » calibration transfer matrix to minimize differences between the conditions under which the standards were analyzed in the laboratory and the conditions on Mars. While the previous model provided good results in the compositional range near the average Mars surface composition, the new model fits the extreme compositions far better. Examples are given for plagioclase feldspars, where silicon was previously significantly over-estimated, and for calcium-sulfate veins, where silicon compositions near zero were inaccurate. Here, the uncertainties of major element abundances are described as a function of the abundances, and are overall significantly lower than the previous model, enabling important new geochemical interpretations of the data.« less

  12. Sources, seasonality, and trends of southeast US aerosol: an integrated analysis of surface, aircraft, and satellite observations with the GEOS-Chem chemical transport model

    NASA Astrophysics Data System (ADS)

    Kim, P. S.; Jacob, D. J.; Fisher, J. A.; Travis, K.; Yu, K.; Zhu, L.; Yantosca, R. M.; Sulprizio, M. P.; Jimenez, J. L.; Campuzano-Jost, P.; Froyd, K. D.; Liao, J.; Hair, J. W.; Fenn, M. A.; Butler, C. F.; Wagner, N. L.; Gordon, T. D.; Welti, A.; Wennberg, P. O.; Crounse, J. D.; St. Clair, J. M.; Teng, A. P.; Millet, D. B.; Schwarz, J. P.; Markovic, M. Z.; Perring, A. E.

    2015-09-01

    We use an ensemble of surface (EPA CSN, IMPROVE, SEARCH, AERONET), aircraft (SEAC4RS), and satellite (MODIS, MISR) observations over the southeast US during the summer-fall of 2013 to better understand aerosol sources in the region and the relationship between surface particulate matter (PM) and aerosol optical depth (AOD). The GEOS-Chem global chemical transport model (CTM) with 25 × 25 km2 resolution over North America is used as a common platform to interpret measurements of different aerosol variables made at different times and locations. Sulfate and organic aerosol (OA) are the main contributors to surface PM2.5 (mass concentration of PM finer than 2.5 μm aerodynamic diameter) and AOD over the southeast US. OA is simulated successfully with a simple parameterization, assuming irreversible uptake of low-volatility products of hydrocarbon oxidation. Biogenic isoprene and monoterpenes account for 60 % of OA, anthropogenic sources for 30 %, and open fires for 10 %. 60 % of total aerosol mass is in the mixed layer below 1.5 km, 25 % in the cloud convective layer at 1.5-3 km, and 15 % in the free troposphere above 3 km. This vertical profile is well captured by GEOS-Chem, arguing against a high-altitude source of OA. The extent of sulfate neutralization (f = [NH4+]/(2[SO42-] + [NO3-]) is only 0.5-0.7 mol mol-1 in the observations, despite an excess of ammonia present, which could reflect suppression of ammonia uptake by OA. This would explain the long-term decline of ammonium aerosol in the southeast US, paralleling that of sulfate. The vertical profile of aerosol extinction over the southeast US follows closely that of aerosol mass. GEOS-Chem reproduces observed total column aerosol mass over the southeast US within 6 %, column aerosol extinction within 16 %, and space-based AOD within 8-28 % (consistently biased low). The large AOD decline observed from summer to winter is driven by sharp declines in both sulfate and OA from August to October. These declines

  13. Preliminary performance assessment of biotoxin detection for UWS applications using a MicroChemLab device.

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    VanderNoot, Victoria A.; Haroldsen, Brent L.; Renzi, Ronald F.

    2010-03-01

    In a multiyear research agreement with Tenix Investments Pty. Ltd., Sandia has been developing field deployable technologies for detection of biotoxins in water supply systems. The unattended water sensor or UWS employs microfluidic chip based gel electrophoresis for monitoring biological analytes in a small integrated sensor platform. This instrument collects, prepares, and analyzes water samples in an automated manner. Sample analysis is done using the {mu}ChemLab{trademark} analysis module. This report uses analysis results of two datasets collected using the UWS to estimate performance of the device. The first dataset is made up of samples containing ricin at varying concentrations andmore » is used for assessing instrument response and detection probability. The second dataset is comprised of analyses of water samples collected at a water utility which are used to assess the false positive probability. The analyses of the two sets are used to estimate the Receiver Operating Characteristic or ROC curves for the device at one set of operational and detection algorithm parameters. For these parameters and based on a statistical estimate, the ricin probability of detection is about 0.9 at a concentration of 5 nM for a false positive probability of 1 x 10{sup -6}.« less

  14. Effects of food processing on food allergens.

    PubMed

    Sathe, Shridhar K; Sharma, Girdhari M

    2009-08-01

    Food allergies are on the rise in Western countries. With the food allergen labeling requirements in the US and EU, there is an interest in learning how food processing affects food allergens. Numerous foods are processed in different ways at home, in institutional settings, and in industry. Depending on the processing method and the food, partial or complete removal of the offending allergen may be possible as illustrated by reduction of peanut allergen in vitro IgE immunoreactivity upon soaking and blanching treatments. When the allergen is discretely located in a food, one may physically separate and remove it from the food. For example, lye peeling has been reported to produce hypoallergenic peach nectar. Protein denaturation and/or hydrolysis during food processing can be used to produce hypoallergenic products. This paper provides a short overview of basic principles of food processing followed by examples of their effects on food allergen stability. Reviewed literature suggests assessment of processing effects on clinically relevant reactivity of food allergens is warranted.

  15. Pastoral mobility and policy recommendations for livestock herding in the Borana pastoral system in southern Ethiopia

    USDA-ARS?s Scientific Manuscript database

    Livelihoods of pastoralists in the Borana Zone of southern Ethiopia have become increasingly vulnerable as a result of stressors like accelerating population growth, shrinking resource availability, sedentarization, and increased frequency and severity of drought. A research team from the USDA Agric...

  16. Application of the WRF-Chem model for the simulation of air quality over Cyprus

    NASA Astrophysics Data System (ADS)

    Kushta, Jonilda; Proestos, Yiannis; Georgiou, George; Christoudias, Theodoros; Lelieveld, Jos

    2017-04-01

    The fully coupled WRF-Chem (Weather Research and Forecasting with Chemistry) model is used to simulate air quality over Cyprus. Cyprus is an island country with complex topography, located in the eastern corner of East Mediterranean region, affected year-long by local, regional and long range transported pollution. An extensive sensitivity analysis of the model performance has been performed over the area of interest with three domains of respective grid spacing of 40, 8 and 2 km. Different configurations have been deployed regarding horizontal resolution, simulation timestep, boundary conditions, NOx emissions and speciation method of emitted NMVOCs (Non Methane Volatile Organic Compounds). The WRF-Chem model simulated hourly concentrations of air pollutants for a month-long period (July 2014) during which measurements are available over 13 stations (4 of which background stations, 1 industrial and 8 urban/traffic stations). The model was initialized with meteorological initial and boundary conditions (ICBC) using NCAR-NCEP's F Global Forecast System output (GFS) at a 1o x1o spatial resolution. The ICBC for the chemical species are derived from the MOZART global model results (2.5o x 2.5o). Both ICBCs datasets are updated every 6 hours. The emission inventory used in the study is the EDGAR-HTAP v2 dataset with a horizontal grid resolution of 0.1o × 0.1o, while an additional dataset with speciated NMVOCs (instead of summed volatile species) is also tested. The diurnal cycle of the atmospheric concentrations of ozone averaged over the island, exhibits a maximum of 114 μg/m3 when the boundary conditions are derived from MOZART and 94 μg/m3 when the boundary conditions are not included (local background and production), suggesting a constant inflow of ozone from long range transport of about 20 μg/m3. The contribution of pollution from regional sources is more pronounced at the western border due to the characteristic summer time north-northeasterly etesian flow

  17. MicroChemLab, A Novel Approach for Handheld Chemical Sensing

    NASA Astrophysics Data System (ADS)

    Lewis, Patrick

    2003-03-01

    In 1996, Sandia National Laboratories began development of a chemical sensing platform based on microfabricated components. The goal of the project was to develop a handheld system for the detection of chemical warfare (CW) agent vapors in air. The components developed for this project are analogous to devices used in analytical laboratories. The benefit of microfabrication is that the resulting components are small and require little power to operate. The key elements of MicroChemLab are a sample collector - preconcentrator, a GC column and a surface acoustic wave (SAW) array detector. The preconcentrator is a thermally isolated silicon nitride membrane with a resistive heater patterned on one side and a sorptive sol gel film deposited on the other. Since the membrane has a very small mass, the resistive heater can ballistically elevate the temperature of the sorptive film to 200° C in approximately 10 ms. The sol gel film collects target compounds efficiently, but rejects volatile industrial solvents like alcohols, ketones, etc. The GC column is a one-meter high aspect ratio spiral channel etched in silicon with an anodically bonded pyrex lid completing the channel. A heater patterned on the silicon allows the column to be temperature ramped. Analytes injected from the preconcentrator are separated in this stage. The SAW array detector contains 3 delay lines used for sensing and 1 reference delay line. Each delay line is driven by an application specific integrated circuit (ASIC) at 500 MHz. Instead of counting frequency, additional ASICs incorporate a phase comparator that delivers a DC signal proportional to the amount of phase change. The three sensing elements of the detector provide a pattern that is indicative of the class of compound detected i.e. nerve agents or blister agents. Combined, these components provide a selective and sensitive handheld solution for the detection of chemical warfare agents. We will present lab data showing the performance of

  18. Baseline levels of melamine in food items sold in Canada. II. Egg, soy, vegetable, fish and shrimp products.

    PubMed

    Tittlemier, Sheryl A; Lau, Benjamin P-Y; Ménard, Cathie; Corrigan, Catherine; Sparling, Melissa; Gaertner, Dean; Cao, Xu-Liang; Dabeka, Bob; Hilts, Carla

    2010-01-01

    A variety of egg-containing, soy-based, fish, shrimp and vegetable products sold in Canada were analysed for melamine (MEL) using a sensitive solid-phase extraction LC-MS/MS analytical method. MEL was detected above the method quantification limit of 0.004 mg/kg in 98 of the 378 samples analysed. Concentrations in the various food product groups ranged 0.00507-0.247 mg/kg (egg-containing items), 0.00408-0.0479 mg/kg (soy-based meat substitutes), 0.00409-1.10 mg/kg (fish and shrimp products), and 0.00464-0.688 mg/kg (vegetable products). MEL was detected less frequently in egg- and soy-containing products. The presence of MEL in most of the Canadian Total Diet Study shrimp composites collected after 2001 suggested the residues in shrimp were caused by a relatively recent exposure to MEL. All concentrations of MEL reported were lower than the 2.5 mg/kg interim standard established for MEL in items containing milk and milk-derived ingredients and the respective maximum residue limits for cyromazine and its metabolite, melamine, in vegetables set by the Canadian Government (2009; http://www.hc-sc.gc.ca/fn-an/securit/chem-chim/melamine/qa-melamine-qr-eng.php#8 ). The consumption of foods containing these low levels of MEL does not constitute a health risk for consumers.

  19. Ultrafine particles from power plants: Evaluation of WRF-Chem simulations with airborne measurements

    NASA Astrophysics Data System (ADS)

    Forkel, Renate; Junkermann, Wolfgang

    2017-04-01

    Ultrafine particles (UFP, particles with a diameter < 100 nm) are an acknowledged risk to human health and have a potential effect on climate as their presence affects the number concentration of cloud condensation nuclei. Despite of the possibly hazardous effects no regulations exist for this size class of ambient air pollution particles. While ground based continuous measurements of UFP are performed in Germany at several sites (e.g. the German Ultrafine Aerosol Network GUAN, Birmili et al. 2016, doi:10.5194/essd-8-355-2016) information about the vertical distribution of UFP within the atmospheric boundary layer is only scarce. This gap has been closed during the last years by regional-scale airborne surveys for UFP concentrations and size distributions over Germany (Junkermann et al., 2016, doi: 10.3402/tellusb.v68.29250) and Australia (Junkermann and Hacker, 2015, doi: 10.3402/tellusb.v67.25308). Power stations and refineries have been identified as a major source of UFP in Germany with observed particle concentrations > 50000 particles cm-3 downwind of these elevated point sources. Nested WRF-Chem simulations with 2 km grid width for the innermost domain are performed with UFP emission source strengths derived from the measurements in order to study the advection and vertical exchange of UFP from power plants near the Czech and Polish border and their impact on planetary boundary layer particle patterns. The simulations are evaluated against the airborne observations and the downward mixing of the UFP from the elevated sources is studied.

  20. [Food allergy, food intolerance or functional disorder?].

    PubMed

    Wüthrich, B

    2009-04-01

    The term "food allergy" is widely misused for all sorts of symptoms and diseases caused by food. Food allergy (FA) is an adverse reaction to food (food hypersensitivity) occurring in susceptible individuals, which is mediated by a classical immune mechanism specific for the food itself. The best established mechanism in FA is due to the presence of IgE antibodies against the offending food. Food intolerance (FI) are all non-immune-mediated adverse reactions to food. The subgroups of FI are enzymatic (e.g. lactose intolerance due to lactase deficiency), pharmacological (reactions against biogenic amines, histamine intolerance), and undefined food intolerance (e.g. against some food additives). The diagnosis of an IgE-mediated FA is made by a carefully taken case history, supported by the demonstration of an IgE sensitization either by skin prick tests or by in vitro tests, and confirmed by positive oral provocation. For scientific purposes the only accepted test for the confirmation of FA/FI is a properly performed double-blind, placebo-controlled food challenge (DBPCFC). A panel of recombinant allergens, produced as single allergenic molecules, may in future improve the diagnosis of IgE-mediated FA. Due to a lack of causal treatment possibilities, the elimination of the culprit "food allergen" from the diet is the only therapeutic option for patients with real food allergy.

  1. Overview of the diagenetic features analyzed by ChemCam onboard Curiosity

    NASA Astrophysics Data System (ADS)

    Mangold, N.; Forni, O.; Nachon, M.; Blaney, D. L.; Wiens, R. C.; Kah, L. C.; Kronyak, R. E.; Clegg, S. M.; Cousin, A.; Fisk, M. R.; Gasnault, O.; Grotzinger, J. P.; Lanza, N.; Lasue, J.; Le Deit, L.; Le Mouelic, S.; Maurice, S.; Meslin, P. Y.; Rapin, W.; Newsom, H. E.; Sumner, D. Y.

    2015-12-01

    The Curiosity rover has encountered a variety of sedimentary rocks with significant variations in both texture and composition. Most of the sandstones and mudstones are interpreted as having been deposited in a fluvio-lacustrine environment, as analyzed in details in the waypoints named Yellowknife Bay, Kimberley and Pahrump. All of these sediments have been crossed by diagenetic features of different composition. Light-toned Ca-sulfate veins observed initially at Yellowknife Bay were observed along the traverse, and in high density at the Pahrump location. As they appear in all sediments and show straight fractures, they correspond to late-stage diagenetic features, due to fluid circulation, with fractures probably due to hydraulic stress at depth. In contrast to light-toned veins, earlier-stage diagenetic features have shown variable composition in the three areas. At Yellowknife Bay, raised ridges display enriched Mg proportion, probably linked to Mg-clay whereas outcrops at Kimberley display fracture fills enriched in Mn and Zn. Pahrump displays a large variety of diagenetic features distinct from these previous examples. Mg-enriched concretions contain S and abundant Ni. Mg enrichments have also been observed in resistant zones along fractures and in resistant layers. Locally concretions also display high Fe, S-bearing material interpreted as Fe-sulfate, probably jarosite. A special location named Garden City at the top of the Parhump sequence displays a complex area with light-toned veins surrounded by darker veins. The latter display strong Ca signatures correlated with F, interpreted as fluorite. No C or S emissions were observed that could alternatively explain the high Ca abundance by carbonates or sulfates. The dark tone of the F-bearing minerals may be due to the presence of Fe. These specific dark veins could derive from the leaching of F-apatite, a mineral that has been observed both in the sandstones and in some of the igneous clasts analyzed by Chem

  2. StandFood: Standardization of Foods Using a Semi-Automatic System for Classifying and Describing Foods According to FoodEx2

    PubMed Central

    Eftimov, Tome; Korošec, Peter; Koroušić Seljak, Barbara

    2017-01-01

    The European Food Safety Authority has developed a standardized food classification and description system called FoodEx2. It uses facets to describe food properties and aspects from various perspectives, making it easier to compare food consumption data from different sources and perform more detailed data analyses. However, both food composition data and food consumption data, which need to be linked, are lacking in FoodEx2 because the process of classification and description has to be manually performed—a process that is laborious and requires good knowledge of the system and also good knowledge of food (composition, processing, marketing, etc.). In this paper, we introduce a semi-automatic system for classifying and describing foods according to FoodEx2, which consists of three parts. The first involves a machine learning approach and classifies foods into four FoodEx2 categories, with two for single foods: raw (r) and derivatives (d), and two for composite foods: simple (s) and aggregated (c). The second uses a natural language processing approach and probability theory to describe foods. The third combines the result from the first and the second part by defining post-processing rules in order to improve the result for the classification part. We tested the system using a set of food items (from Slovenia) manually-coded according to FoodEx2. The new semi-automatic system obtained an accuracy of 89% for the classification part and 79% for the description part, or an overall result of 79% for the whole system. PMID:28587103

  3. StandFood: Standardization of Foods Using a Semi-Automatic System for Classifying and Describing Foods According to FoodEx2.

    PubMed

    Eftimov, Tome; Korošec, Peter; Koroušić Seljak, Barbara

    2017-05-26

    The European Food Safety Authority has developed a standardized food classification and description system called FoodEx2. It uses facets to describe food properties and aspects from various perspectives, making it easier to compare food consumption data from different sources and perform more detailed data analyses. However, both food composition data and food consumption data, which need to be linked, are lacking in FoodEx2 because the process of classification and description has to be manually performed-a process that is laborious and requires good knowledge of the system and also good knowledge of food (composition, processing, marketing, etc.). In this paper, we introduce a semi-automatic system for classifying and describing foods according to FoodEx2, which consists of three parts. The first involves a machine learning approach and classifies foods into four FoodEx2 categories, with two for single foods: raw (r) and derivatives (d), and two for composite foods: simple (s) and aggregated (c). The second uses a natural language processing approach and probability theory to describe foods. The third combines the result from the first and the second part by defining post-processing rules in order to improve the result for the classification part. We tested the system using a set of food items (from Slovenia) manually-coded according to FoodEx2. The new semi-automatic system obtained an accuracy of 89% for the classification part and 79% for the description part, or an overall result of 79% for the whole system.

  4. Assessing regional scale predictions of aerosols, marine stratocumulus, and their interactions during VOCALS-REx using WRF-Chem

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Yang Q.; Lee Y.; Gustafson Jr., W. I.

    2011-12-02

    This study assesses the ability of the recent chemistry version (v3.3) of the Weather Research and Forecasting (WRF-Chem) model to simulate boundary layer structure, aerosols, stratocumulus clouds, and energy fluxes over the Southeast Pacific Ocean. Measurements from the VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx) and satellite retrievals (i.e., products from the MODerate resolution Imaging Spectroradiometer (MODIS), Clouds and Earth's Radiant Energy System (CERES), and GOES-10) are used for this assessment. The Morrison double-moment microphysics scheme is newly coupled with interactive aerosols in the model. The 31-day (15 October-16 November 2008) WRF-Chem simulation with aerosol-cloud interactions (AERO hereafter) is also comparedmore » to a simulation (MET hereafter) with fixed cloud droplet number concentrations in the microphysics scheme and simplified cloud and aerosol treatments in the radiation scheme. The well-simulated aerosol quantities (aerosol number, mass composition and optical properties), and the inclusion of full aerosol-cloud couplings lead to significant improvements in many features of the simulated stratocumulus clouds: cloud optical properties and microphysical properties such as cloud top effective radius, cloud water path, and cloud optical thickness. In addition to accounting for the aerosol direct and semi-direct effects, these improvements feed back to the simulation of boundary-layer characteristics and energy budgets. Particularly, inclusion of interactive aerosols in AERO strengthens the temperature and humidity gradients within the capping inversion layer and lowers the marine boundary layer (MBL) depth by 130 m from that of the MET simulation. These differences are associated with weaker entrainment and stronger mean subsidence at the top of the MBL in AERO. Mean top-of-atmosphere outgoing shortwave fluxes, surface latent heat, and surface downwelling longwave fluxes are in better agreement with

  5. A new chemistry option in WRF-Chem v. 3.4 for the simulation of direct and indirect aerosol effects using VBS: evaluation against IMPACT-EUCAARI data

    NASA Astrophysics Data System (ADS)

    Tuccella, P.; Curci, G.; Grell, G. A.; Visconti, G.; Crumeyrolle, S.; Schwarzenboeck, A.; Mensah, A. A.

    2015-09-01

    A parameterization for secondary organic aerosol (SOA) production based on the volatility basis set (VBS) approach has been coupled with microphysics and radiative schemes in the Weather Research and Forecasting model with Chemistry (WRF-Chem) model. The new chemistry option called "RACM-MADE-VBS-AQCHEM" was evaluated on a cloud resolving scale against ground-based and aircraft measurements collected during the IMPACT-EUCAARI (Intensive Cloud Aerosol Measurement Campaign - European Integrated project on Aerosol Cloud Climate and Air quality interaction) campaign, and complemented with satellite data from MODIS. The day-to-day variability and the diurnal cycle of ozone (O3) and nitrogen oxides (NOx) at the surface are captured by the model. Surface aerosol mass concentrations of sulfate (SO4), nitrate (NO3), ammonium (NH4), and organic matter (OM) are simulated with correlations larger than 0.55. WRF-Chem captures the vertical profile of the aerosol mass concentration in both the planetary boundary layer (PBL) and free troposphere (FT) as a function of the synoptic condition, but the model does not capture the full range of the measured concentrations. Predicted OM concentration is at the lower end of the observed mass concentrations. The bias may be attributable to the missing aqueous chemistry processes of organic compounds and to uncertainties in meteorological fields. A key role could be played by assumptions on the VBS approach such as the SOA formation pathways, oxidation rate, and dry deposition velocity of organic condensable vapours. Another source of error in simulating SOA is the uncertainties in the anthropogenic emissions of primary organic carbon. Aerosol particle number concentration (condensation nuclei, CN) is overestimated by a factor of 1.4 and 1.7 within the PBL and FT, respectively. Model bias is most likely attributable to the uncertainties of primary particle emissions (mostly in the PBL) and to the nucleation rate. Simulated cloud

  6. Palatable food consumption in children: interplay between (food) reward motivation and the home food environment.

    PubMed

    De Decker, Annelies; Verbeken, Sandra; Sioen, Isabelle; Van Lippevelde, Wendy; Braet, Caroline; Eiben, Gabriele; Pala, Valeria; Reisch, Lucia A; De Henauw, Stefaan

    2017-04-01

    To understand the importance of the home food environment on unhealthy food consumption in children high in reward sensitivity, this study tested the hypothesis that the home availability of unhealthy food moderates the effect of reward sensitivity on children's fast-food consumption frequency, exerted via food cue responsiveness. Children between 7.5 and 14 years (n = 174, 50.6% boys) reported on reward sensitivity and food cue responsiveness (by means of the subscale 'external eating'). Their height and weight were measured. Parents reported on their children's fast-food consumption frequency, food cue responsiveness (by means of the subscale 'food responsiveness'), and on the home availability of unhealthy foods. Two moderated mediation models were conducted, one with the parent- and one with the child-reported food cue responsiveness as mediator. Findings suggested that with a high home availability of unhealthy foods, (a) a higher fast-food consumption frequency was found in children high in reward sensitivity and (b) the relation between reward sensitivity and the fast-food consumption frequency was mediated by external eating. The findings point at the importance of the home food environment in children high in reward sensitivity. They suggest to limit the home availability of unhealthy foods. What is Known: • Reward sensitivity (RS) is positively associated with children's palatable food consumption • In adolescents, this effect is mediated by food cue responsiveness, which determines the strength of an individual's motivation to obtain food when perceiving food cues What is New: • Children high in RS may be more vulnerable to palatable food cues in their everyday food environment because of a higher food cue responsiveness • The home food environment may be an important determining factor of the palatable food consumption of these children.

  7. Fast Foods, Organic Foods, Fad Diets

    USDA-ARS?s Scientific Manuscript database

    There is no standard definition of fast food. Generally, fast food is eaten without cutlery, and fast-food restaurants have no wait staff. Failure to have a standardized definition makes it difficult to compare studies. Foods available outside the home tend to be high in energy and fat compared w...

  8. Moderate alcohol consumption stimulates food intake and food reward of savoury foods.

    PubMed

    Schrieks, Ilse C; Stafleu, Annette; Griffioen-Roose, Sanne; de Graaf, Cees; Witkamp, Renger F; Boerrigter-Rijneveld, Rianne; Hendriks, Henk F J

    2015-06-01

    The aim of this study was to investigate whether food reward plays a role in the stimulating effect of moderate alcohol consumption on subsequent food intake. In addition, we explored the role of oral and gut sensory pathways in alcohol's effect on food reward by modified sham feeding (MSF) or consumption of a preload after alcohol intake.In a single-blind crossover design, 24 healthy men were randomly assigned to either consumption of vodka/orange juice (20 g alcohol) or orange juice only, followed by consumption of cake, MSF of cake or no cake. Food reward was evaluated by actual food intake measured by an ad libitum lunch 45 min after alcohol ingestion and by behavioural indices of wanting and liking of four food categories (high fat, low fat, sweet and savoury).Moderate alcohol consumption increased food intake during the ad libitum lunch by 11% (+338 kJ, P = 0.004). Alcohol specifically increased intake (+127 kJ, P <0.001) and explicit liking (P = 0.019) of high-fat savoury foods. Moreover, moderate alcohol consumption increased implicit wanting for savoury (P = 0.013) and decreased implicit wanting for sweet (P = 0.017) before the meal. Explicit wanting of low-fat savoury foods only was higher after alcohol followed by no cake as compared to after alcohol followed by cake MSF (P = 0.009), but not as compared to alcohol followed by cake consumption (P = 0.082). Both cake MSF and cake consumption had no overall effect on behavioural indices of food reward.To conclude, moderate alcohol consumption increased subsequent food intake, specifically of high-fat savoury foods. This effect was related to the higher food reward experienced for savoury foods. The importance of oral and gut sensory signalling in alcohol's effect on food reward remains largely unclear. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Food crises, food regimes and food movements: rumblings of reform or tides of transformation?

    PubMed

    Holt Giménez, Eric; Shattuck, Annie

    2011-01-01

    This article addresses the potential for food movements to bring about substantive changes to the current global food system. After describing the current corporate food regime, we apply Karl Polanyi's 'double-movement' thesis on capitalism to explain the regime's trends of neoliberalism and reform. Using the global food crisis as a point of departure, we introduce a comparative analytical framework for different political and social trends within the corporate food regime and global food movements, characterizing them as 'Neoliberal', 'Reformist', 'Progressive', and 'Radical', respectively, and describe each trend based on its discourse, model, and key actors, approach to the food crisis, and key documents. After a discussion of class, political permeability, and tensions within the food movements, we suggest that the current food crisis offers opportunities for strategic alliances between Progressive and Radical trends within the food movement. We conclude that while the food crisis has brought a retrenchment of neoliberalization and weak calls for reform, the worldwide growth of food movements directly and indirectly challenge the legitimacy and hegemony of the corporate food regime. Regime change will require sustained pressure from a strong global food movement, built on durable alliances between Progressive and Radical trends.

  10. Ensuring Food Security Through Enhancing Microbiological Food Safety

    NASA Astrophysics Data System (ADS)

    Mikš-Krajnik, Marta; Yuk, Hyun-Gyun; Kumar, Amit; Yang, Yishan; Zheng, Qianwang; Kim, Min-Jeong; Ghate, Vinayak; Yuan, Wenqian; Pang, Xinyi

    2015-10-01

    Food safety and food security are interrelated concepts with a profound impact on the quality of human life. Food security describes the overall availability of food at different levels from global to individual household. While, food safety focuses on handling, preparation and storage of foods in order to prevent foodborne illnesses. This review focuses on innovative thermal and non-thermal technologies in the area of food processing as the means to ensure food security through improving food safety with emphasis on the reduction and control of microbiological risks. The antimicrobial efficiency and mechanism of new technologies to extend the shelf life of food product were also discussed.

  11. Recalibration of the Mars Science Laboratory ChemCam instrument with an expanded geochemical database

    USGS Publications Warehouse

    Clegg, Samuel M.; Wiens, Roger C.; Anderson, Ryan; Forni, Olivier; Frydenvang, Jens; Lasue, Jeremie; Cousin, Agnes; Payre, Valerie; Boucher, Tommy; Dyar, M. Darby; McLennan, Scott M.; Morris, Richard V.; Graff, Trevor G.; Mertzman, Stanley A; Ehlmann, Bethany L.; Belgacem, Ines; Newsom, Horton E.; Clark, Ben C.; Melikechi, Noureddine; Mezzacappa, Alissa; McInroy, Rhonda E.; Martinez, Ronald; Gasda, Patrick J.; Gasnault, Olivier; Maurice, Sylvestre

    2017-01-01

    The ChemCam Laser-Induced Breakdown Spectroscopy (LIBS) instrument onboard the Mars Science Laboratory (MSL) rover Curiosity has obtained > 300,000 spectra of rock and soil analysis targets since landing at Gale Crater in 2012, and the spectra represent perhaps the largest publicly-available LIBS datasets. The compositions of the major elements, reported as oxides (SiO2, TiO2, Al2O3, FeOT, MgO, CaO, Na2O, K2O), have been re-calibrated using a laboratory LIBS instrument, Mars-like atmospheric conditions, and a much larger set of standards (408) that span a wider compositional range than previously employed. The new calibration uses a combination of partial least squares (PLS1) and Independent Component Analysis (ICA) algorithms, together with a calibration transfer matrix to minimize differences between the conditions under which the standards were analyzed in the laboratory and the conditions on Mars. While the previous model provided good results in the compositional range near the average Mars surface composition, the new model fits the extreme compositions far better. Examples are given for plagioclase feldspars, where silicon was significantly over-estimated by the previous model, and for calcium-sulfate veins, where silicon compositions near zero were inaccurate. The uncertainties of major element abundances are described as a function of the abundances, and are overall significantly lower than the previous model, enabling important new geochemical interpretations of the data.

  12. Neighborhood fast food availability and fast food consumption.

    PubMed

    Oexle, Nathalie; Barnes, Timothy L; Blake, Christine E; Bell, Bethany A; Liese, Angela D

    2015-09-01

    Recent nutritional and public health research has focused on how the availability of various types of food in a person's immediate area or neighborhood influences his or her food choices and eating habits. It has been theorized that people living in areas with a wealth of unhealthy fast-food options may show higher levels of fast-food consumption, a factor that often coincides with being overweight or obese. However, measuring food availability in a particular area is difficult to achieve consistently: there may be differences in the strict physical locations of food options as compared to how individuals perceive their personal food availability, and various studies may use either one or both of these measures. The aim of this study was to evaluate the association between weekly fast-food consumption and both a person's perceived availability of fast-food and an objective measure of fast-food presence - Geographic Information Systems (GIS) - within that person's neighborhood. A randomly selected population-based sample of eight counties in South Carolina was used to conduct a cross-sectional telephone survey assessing self-report fast-food consumption and perceived availability of fast food. GIS was used to determine the actual number of fast-food outlets within each participant's neighborhood. Using multinomial logistic regression analyses, we found that neither perceived availability nor GIS-based presence of fast-food was significantly associated with weekly fast-food consumption. Our findings indicate that availability might not be the dominant factor influencing fast-food consumption. We recommend using subjective availability measures and considering individual characteristics that could influence both perceived availability of fast food and its impact on fast-food consumption. If replicated, our findings suggest that interventions aimed at reducing fast-food consumption by limiting neighborhood fast-food availability might not be completely effective

  13. Food Safety, Food Fraud, and Food Defense: A Fast Evolving Literature.

    PubMed

    Manning, Louise; Soon, Jan Mei

    2016-04-01

    Intentional food crime is plural in nature in terms of the types of crime and the differing levels of financial gain. Successful models of food crime are dependent on how well the crime has been executed and at what point, or even if, detection actually occurs. The aim of this paper is to undertake a literature review and critique the often contradictory definitions that can be found in the literature in order to compare and contrast existing food crime risk assessment tools and their application. Food safety, food defense, and food fraud risk assessments consider different criteria in order to determine the degree of situational risk for each criteria and the measures that need to be implemented to mitigate that risk. Further research is required to support the development of global countermeasures, that are of value in reducing overall risk even when the potential hazards may be largely unknown, and specific countermeasures that can act against unique risks. © 2016 Institute of Food Technologists®

  14. Emergency Food Supplies in Food Secure Households.

    PubMed

    Golem, Devon L; Byrd-Bredbenner, Carol

    2015-08-01

    Introduction Limited food supply paired with reduced access to food during emergency disasters can lead to malnutrition. To date, research evaluating the adequacy of household emergency food supplies relies on self-reported data from surveys and has not been measured objectively in households in the United States. The main objective of this study was to describe household calorie availability and nutrient density in a normal situation and to project changes that could occur when emergencies (eg, natural disasters) restrict replenishment of food supplies and disrupt water and/or energy needed for food preparation and storage. Hypothesis The calorie availability of the food supply within households in New Jersey (USA) is anticipated to be well above the recommended 3-day period. However, it is anticipated that the nutritional density of the food supply within these households will be negative. Additionally, the disaster-related factors that diminish the ability to consume stored food (eg, lack of water, power for cooking, and/or proper storage) will further reduce the caloric and nutritional adequacy of the household food supply. The household food supplies of 100 food secure families in New Jersey were inventoried at a non-emergency point in time. The number of days that the inventoried food supply would provide all household members 100% of the daily value (DV) for calories and other nutrients was determined. Additionally, the effects of water and power shortages on nutritional availability of household food supply were estimated. The households had an average of 33.16 days (SD=21.97; range=8.14-125.17 days) of calories at 100% DV for all household members. Lack of water, energy for cooking, or both would render a decrease in the total household calories by 28%, 35%, or 38%, respectively. Loss of power for greater than five days would reduce availability of household calories by 27%. A positive nutrient density was observed with and without the food

  15. Climate Change and Global Food Security: Food Access, Utilization, and the US Food System

    NASA Astrophysics Data System (ADS)

    Brown, M. E.; Antle, J. M.; Backlund, P. W.; Carr, E. R.; Easterling, W. E.; Walsh, M.; Ammann, C. M.; Attavanich, W.; Barrett, C. B.; Bellemare, M. F.; Dancheck, V.; Funk, C.; Grace, K.; Ingram, J. S. I.; Jiang, H.; Maletta, H.; Mata, T.; Murray, A.; Ngugi, M.; Ojima, D. S.; O'Neill, B. C.; Tebaldi, C.

    2015-12-01

    This paper will summarize results from the USDA report entitled 'Climate change, Global Food Security and the U.S. Food system'. The report focuses on the impact of climate change on global food security, defined as "when all people at all times have physical, social, and economic access to sufficient, safe, and nutritious food to meet their dietary needs and food preferences for an active and healthy life". The assessment brought together authors and contributors from twenty federal, academic, nongovernmental, intergovernmental, and private organizations in four countries to identify climate change effects on food security through 2100, and analyze the U.S.'s likely connections with that world. This talk will describe how climate change will likely affect food access and food utilization, and summarize how the U.S. food system contributes to global food security, and will be affected by climate change.

  16. [Food neophobia: impact on food habits and acceptance of healthy foods in schoolchildren].

    PubMed

    Rodríguez-Tadeo, Alejandra; Patiño Villena, Begoña; Urquidez-Romero, Rene; Vidaña-Gaytán, María Elena; Periago Caston, María Jesús; Ros Berruezo, Gaspar; González Martinez-Lacuesta, Eduardo

    2014-09-21

    In children, food neophobia may affect food choices and limit the variety of the diet as well as affect the sensory acceptance of new foods. To identify the impact of food neophobia in food habits and preferences of healthy food in school canteens users in the city of Murcia. A total of 242 children in the second and third cycle of primary education (8-12 years), were included, stratified by sex and school year. A survey of habits and food preferences, food neophobia and acceptance of foods commonly consumed in the dining room was applied. In addition, a sensory test was conducted and the consumption of salads and fruits in the room was measured by the weighing method. The prevalence of neophobia was 16%, without difference by sex, academic year, time to use service, parental origin and being overweight or underweight. Food neophobia was associated with a detrimental effect on the consumption of vegetables and fruit, the taste for vegetables and lower consumption of cereals and cereal at breakfast and preferably less fruit and vegetables (p<0.05). A higher level of neophobia less acceptance was given to foods like chicken and lentils (p<0.05), fruit, salads and legumes (p<0.001). Food neophobia did not affect the hedonic acceptance of fruit and salads consumed in the cafeteria. It is necessary to integrate this information to stakeholders to ensure an improvement in the consumption of healthy foods. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

  17. Toddlers' food preferences. The impact of novel food exposure, maternal preferences and food neophobia.

    PubMed

    Howard, Anika J; Mallan, Kimberley M; Byrne, Rebecca; Magarey, Anthea; Daniels, Lynne A

    2012-12-01

    Food preferences have been identified as a key determinant of children's food acceptance and consumption. The aim of this study was to identify factors that influence children's liking for fruits, vegetables and non-core foods. Participants were Australian mothers (median age at delivery=31years, 18-46years) and their two-year-old children (M=24months, SD=1month; 52% female) allocated to the control group (N=245) of the NOURISH RCT. The effects of repeated exposure to new foods, maternal food preferences and child food neophobia on toddlers' liking of vegetables, fruits and non-core foods and the proportion never tried were examined via hierarchical regression models; adjusting for key maternal (age, BMI, education) and child covariates (birth weight Z-score, gender), duration of breastfeeding and age of introduction to solids. Maternal preferences corresponded with child preferences. Food neophobia among toddlers was associated with liking fewer vegetables and fruits, and trying fewer vegetables. Number of repeated exposures to new food was not significantly associated with food liking at this age. Results highlight the need to: (i) encourage parents to offer a wide range of foods, regardless of their own food preferences, and (ii) provide parents with guidance on managing food neophobia. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

  18. PARAMETRIC DISTANCE WEIGHTING OF LANDSCAPE INFLUENCE ON STREAMS

    EPA Science Inventory

    We present a parametric model for estimating the areas within watersheds whose land use best predicts indicators of stream ecological condition. We regress a stream response variable on the distance-weighted proportion of watershed area that has a specific land use, such as agric...

  19. Combining the U.S. National Lake Assessment and the USGS MRB1 Sparrow Model to Estimate the Potential of Northeastern Lakes to Provide Cultural Ecosystem Serivces

    EPA Science Inventory

    Lakes provide a variety of ecosystem service benefits that are important to communities in the United States. Standard water quality indicators can be used to assess a lake’s potential to provide ecosystem services such as provisioning of water for domestic, industrial, and agric...

  20. Irrigation of floricultural and nursery crops with saline wastewaters

    USDA-ARS?s Scientific Manuscript database

    Water security has become a major concern throughout the western United States and other arid and semiarid regions worldwide. Uncertainties concerning the allocation and dependability of good quality water have led to increased interest in the use alternative, non-potable waters for irrigated agric...

  1. PESTICIDES IN DUST SAMPLES FROM HOMES AND SCHOOLS IN YUMA, ARIZONA

    EPA Science Inventory

    A pilot study was conducted in Yuma, Arizona to investigate children's exposure to pesticides as detected in urine and dust samples. The principle hypothesis of the study is that pesticide levels in young children vary with the distance children live or attend school from agric...

  2. [Review of food policy approaches: from food security to food sovereignty (2000-2013)].

    PubMed

    López-Giraldo, Luis Alirio; Franco-Giraldo, Álvaro

    2015-07-01

    Food policies have attracted special interest due to the global food crisis in 2008 and promotion of the Millennium Development Goals, leading to approaches by different fields. This thematic review aims to describe the main theoretical and methodological approaches to food security and food sovereignty policies. A search was performed in databases of scientific journals from 2000 to 2013. 320 complete articles were selected from a total of 2,699. After reading the articles to apply the inclusion criteria, 55 items were maintained for analysis. In conclusion, with the predominance of food security as a guiding policy, food sovereignty has emerged as a critical response to be included in designing and researching food policies. Food policies are essential for achieving public health goals. Public health should thus take a leading role in linking and orienting such policies.

  3. Association between food insecurity and food intake.

    PubMed

    Araújo, Melissa Luciana de; Mendonça, Raquel de Deus; Lopes Filho, José Divino; Lopes, Aline Cristine Souza

    2018-03-28

    We aim to identify the prevalence of food insecurity and to ascertain the association between food insecurity and food intake. A cross-sectional survey. The study included users of a primary healthcare service in Belo Horizonte, Brazil, from 2013 to 2014. Socioeconomic, health, and food intake data were gathered using a questionnaire and the Brazilian Food Insecurity Scale. Individuals 20 years old or older (n = 2817). The prevalence of food insecurity among families with individuals under 18 years was 41.0%, and 26.4% in other households. After adjusting for potential confounders, the households in food insecurity with members under 18 years old, the consumption of fruits and vegetables (RP = 0.70, 95%IC: 0.58-0.84), and fruits (RP = 0.74, 95%IC: 0.59-0.93) was lower; and consumption of beans was higher (RP = 1.49, 95%IC: 1.06-2.09) compared to those with food security. In households without members under 18 years old, the consumption of fruits and vegetables (RP = 0.68, 95%IC: 0.58-0.79), fruits (RP = 0.61, 95%IC: 0.50-0.74), and beans (RP = 0.78, 95%IC: 0.63-0.97) was lower; and the consumption of tubers (RP = 1.36, 95%IC: 1.03-1.79) was higher. However, the state of food insecurity did not affect the consumption of ultra-processed foods, independently of age, sex, marital status, educational level, and employed status. Food insecurity negatively affected the fruit and vegetable consumption in both types of families tested. The consumption of beans was higher in households with children and adolescents, and the consumption of tubers was higher in households without children and adolescents. However, food insecurity did not change the intake of ultraprocessed foods. Copyright © 2018 Elsevier Inc. All rights reserved.

  4. Quantifying food waste in Hawaii's food supply chain.

    PubMed

    Loke, Matthew K; Leung, PingSun

    2015-12-01

    Food waste highlights a considerable loss of resources invested in the food supply chain. While it receives a lot of attention in the global context, the assessment of food waste is deficient at the sub-national level, owing primarily to an absence of quality data. This article serves to explore that gap and aims to quantify the edible weight, economic value, and calorie equivalent of food waste in Hawaii. The estimates are based on available food supply data for Hawaii and the US Department of Agriculture's (USDA's) loss-adjusted food availability data for defined food groups at three stages of the food supply chain. At its highest aggregated level, we estimate Hawaii's food waste generation at 237,122 t or 26% of available food supply in 2010. This is equivalent to food waste of 161.5 kg per person, per annum. Additionally, this food waste is valued at US$1.025 billion annually or the equivalent of 502.6 billion calories. It is further evident that the occurrence of food waste by all three measures is highest at the consumer stage, followed by the distribution and retail stage, and is lowest at the post-harvest and packing stage. The findings suggest that any meaningful intervention to reduce food waste in Hawaii should target the consumer, and distribution and retail stages of the food supply chain. Interventions at the consumer stage should focus on the two protein groups, as well as fresh fruits and fresh vegetables. © The Author(s) 2015.

  5. 21 CFR 170.10 - Food additives in standardized foods.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Food additives in standardized foods. 170.10... (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES General Provisions § 170.10 Food additives... the Act, which proposes the inclusion of a food additive in such definition and standard of identity...

  6. 21 CFR 170.10 - Food additives in standardized foods.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Food additives in standardized foods. 170.10... (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES General Provisions § 170.10 Food additives... the Act, which proposes the inclusion of a food additive in such definition and standard of identity...

  7. 21 CFR 170.10 - Food additives in standardized foods.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Food additives in standardized foods. 170.10... (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES General Provisions § 170.10 Food additives... the Act, which proposes the inclusion of a food additive in such definition and standard of identity...

  8. 21 CFR 170.10 - Food additives in standardized foods.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Food additives in standardized foods. 170.10... (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES General Provisions § 170.10 Food additives... the Act, which proposes the inclusion of a food additive in such definition and standard of identity...

  9. 21 CFR 170.10 - Food additives in standardized foods.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Food additives in standardized foods. 170.10... (CONTINUED) FOOD ADDITIVES General Provisions § 170.10 Food additives in standardized foods. (a) The... inclusion of a food additive in such definition and standard of identity, the provisions of the regulations...

  10. Prediction of drug transport processes using simple parameters and PLS statistics. The use of ACD/logP and ACD/ChemSketch descriptors.

    PubMed

    Osterberg, T; Norinder, U

    2001-01-01

    A method of modelling and predicting biopharmaceutical properties using simple theoretically computed molecular descriptors and multivariate statistics has been investigated for several data sets related to solubility, IAM chromatography, permeability across Caco-2 cell monolayers, human intestinal perfusion, brain-blood partitioning, and P-glycoprotein ATPase activity. The molecular descriptors (e.g. molar refractivity, molar volume, index of refraction, surface tension and density) and logP were computed with ACD/ChemSketch and ACD/logP, respectively. Good statistical models were derived that permit simple computational prediction of biopharmaceutical properties. All final models derived had R(2) values ranging from 0.73 to 0.95 and Q(2) values ranging from 0.69 to 0.86. The RMSEP values for the external test sets ranged from 0.24 to 0.85 (log scale).

  11. Trace element geochemistry (Li, Ba, Sr, and Rb) using Curiosity's ChemCam: early results for Gale crater from Bradbury Landing Site to Rocknest

    USGS Publications Warehouse

    Ollila, Ann M.; Newsom, Horton E.; Clark, Benton; Wiens, Roger C.; Cousin, Agnes; Blank, Jen G.; Mangold, Nicolas; Sautter, Violaine; Maurice, Sylvestre; Clegg, Samuel M.; Gasnault, Olivier; Forni, Olivier; Tokar, Robert; Lewin, Eric; Dyar, M. Darby; Lasue, Jeremie; Anderson, Ryan; McLennan, Scott M.; Bridges, John; Vaniman, Dave; Lanza, Nina; Fabre, Cecile; Melikechi, Noureddine; Perett, Glynis M.; Campbell, John L.; King, Penelope L.; Barraclough, Bruce; Delapp, Dorothea; Johnstone, Stephen; Meslin, Pierre-Yves; Rosen-Gooding, Anya; Williams, Josh

    2014-01-01

    The ChemCam instrument package on the Mars rover, Curiosity, provides new capabilities to probe the abundances of certain trace elements in the rocks and soils on Mars using the laser-induced breakdown spectroscopy technique. We focus on detecting and quantifying Li, Ba, Rb, and Sr in targets analyzed during the first 100 sols, from Bradbury Landing Site to Rocknest. Univariate peak area models and multivariate partial least squares models are presented. Li, detected for the first time directly on Mars, is generally low (100 ppm and >1000 ppm, respectively. These analysis locations tend to have high Si and alkali abundances, consistent with a feldspar composition. Together, these trace element observations provide possible evidence of magma differentiation and aqueous alteration.

  12. Preventing food crises using a food policy approach.

    PubMed

    Timmer, C Peter

    2010-01-01

    A food crisis occurs when rates of hunger and malnutrition rise sharply at local, national, or global levels. This definition distinguishes a food crisis from chronic hunger, although food crises are far more likely among populations already suffering from prolonged hunger and malnutrition. A food crisis is usually set off by a shock to either supply or demand for food and often involves a sudden spike in food prices. It is important to remember that in a market economy, food prices measure the scarcity of food, not its value in any nutritional sense. Except in rare circumstances, the straightforward way to prevent a food crisis is to have rapidly rising labor productivity through economic growth and keep food prices stable while maintaining access by the poor. The formula is easier to state than to implement, especially on a global scale, but it is good to have both the objective, reducing short-run spikes in hunger, and the deep mechanisms, pro-poor economic growth and stable food prices, clearly in mind. A coherent food policy seeks to use these mechanisms, and others, to achieve a sustained reduction in chronic hunger over the long run while preventing spikes in hunger in the short run.

  13. Food waste and the food-energy-water nexus: A review of food waste management alternatives.

    PubMed

    Kibler, Kelly M; Reinhart, Debra; Hawkins, Christopher; Motlagh, Amir Mohaghegh; Wright, James

    2018-04-01

    Throughout the world, much food produced is wasted. The resource impact of producing wasted food is substantial; however, little is known about the energy and water consumed in managing food waste after it has been disposed. Herein, we characterize food waste within the Food-Energy-Water (FEW) nexus and parse the differential FEW effects of producing uneaten food and managing food loss and waste. We find that various food waste management options, such as waste prevention, landfilling, composting, anaerobic digestion, and incineration, present variable pathways for FEW impacts and opportunities. Furthermore, comprehensive sustainable management of food waste will involve varied mechanisms and actors at multiple levels of governance and at the level of individual consumers. To address the complex food waste problem, we therefore propose a "food-waste-systems" approach to optimize resources within the FEW nexus. Such a framework may be applied to devise strategies that, for instance, minimize the amount of edible food that is wasted, foster efficient use of energy and water in the food production process, and simultaneously reduce pollution externalities and create opportunities from recycled energy and nutrients. Characterization of FEW nexus impacts of wasted food, including descriptions of dynamic feedback behaviors, presents a significant research gap and a priority for future work. Large-scale decision making requires more complete understanding of food waste and its management within the FEW nexus, particularly regarding post-disposal impacts related to water. Copyright © 2018 Elsevier Ltd. All rights reserved.

  14. Resiliency in forage and grazinglands

    USDA-ARS?s Scientific Manuscript database

    This manuscript is a combined effort of the speakers at the 2017 C6 Forage and Grazinglands Division Symposia which was titled “Resiliency in Forage and Grazinglands.” Developing more resilient agroecosystems, including those that produce forage and livestock, will become necessary to maintain agric...

  15. 78 FR 49990 - Dean Foods Company and WhiteWave Foods Company; Filing of Food Additive Petition

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-16

    .... FDA-2013-N-0888] Dean Foods Company and WhiteWave Foods Company; Filing of Food Additive Petition... the WhiteWave Foods Company proposing that the food additive regulations be amended to provide for the expanded safe uses of vitamin D 2 and vitamin D 3 as nutrient supplements in food. DATES: The food additive...

  16. Food Supply and Food Safety Issues in China

    PubMed Central

    Lam, Hon-Ming; Remais, Justin; Fung, Ming-Chiu; Xu, Liqing; Sun, Samuel Sai-Ming

    2013-01-01

    Food supply and food safety are major global public health issues, and are particularly important in heavily populated countries such as China. Rapid industrialisation and modernisation in China are having profound effects on food supply and food safety. In this Review, we identified important factors limiting agricultural production in China, including conversion of agricultural land to other uses, freshwater deficits, and soil quality issues. Additionally, increased demand for some agricultural products is examined, particularly those needed to satisfy the increased consumption of animal products in the Chinese diet, which threatens to drive production towards crops used as animal feed. Major sources of food poisoning in China include pathogenic microorganisms, toxic animals and plants entering the food supply, and chemical contamination. Meanwhile, two growing food safety issues are illegal additives and contamination of the food supply by toxic industrial waste. China’s connections to global agricultural markets are also having important effects on food supply and food safety within the country. Although the Chinese Government has shown determination to reform laws, establish monitoring systems, and strengthen food safety regulation, weak links in implementation remain. PMID:23746904

  17. Traditional food and monetary access to market-food: correlates of food insecurity among Inuit preschoolers.

    PubMed

    Egeland, Grace M; Williamson-Bathory, Laakkuluk; Johnson-Down, Louise; Sobol, Isaac

    2011-09-01

    To evaluate correlates of food insecurity among Inuit preschoolers. Study design. Cross-sectional health survey. Correlates of food insecurity were assessed in 3-5 year old children (n=388) residing in 16 Nunavut communities (2007-2008) in whom a high prevalence of child food insecurity (56%) has been documented. A bilingual team conducted interviews, including 24-hour dietary recalls and past-year food security assessment involving monetary access to market foods. Children residing in child food insecure homes were more likely to have consumed traditional food (TF) (51.7% vs. 39.9%, p ≤ 0.01), and less likely to have consumed any milk (52.2% vs. 73.2%, p ≤ 0.001) compared to children in child food secure homes. Median healthy eating index scores were significantly lower (77.1 vs. 79.9, p ≤ 0.01) and sugar drink intake higher (429 vs. 377 g/day, p ≤ 0.05) in children from child food insecure than food secure households. Children that consumed TF had higher protein and lower carbohydrate intake (p ≤ 0.05) and tendencies for a lower prevalence of iron deficiency (plasma ferritin <12 μg/l; p ≤ 0.10) regardless of food security status. A borderline significant interaction of TF by food security status (p ≤ 0.10) was observed where the percent of anemia (hemoglobin <110 and <115 g/l for 3-4 and 5 yr. olds, respectively) was highest among children from child food insecure homes who consumed no TF. TF and market food contribute to food security and both need to be considered in food security assessments. Support systems and dietary interventions for families with young children are needed.

  18. Application of WRF/Chem over the Continental U.S. under the AQMEII Phase II: Part 2. Evaluation of 2010 Application and Responses of Air Quality and Meteorology-Chemistry Interactions to Changes in Emissions and Meteorology from 2006 to 2010

    EPA Science Inventory

    The Weather Research and Forecasting model with Chemistry (WRF/Chem) simulation with the 2005 Carbon Bond (CB05) gas-phase mechanism coupled to the Modal for Aerosol Dynamics for Europe (MADE) and the Volatility Basis Set (VBS) approach for secondary organic aerosol (SOA) (MADE/V...

  19. Food additives, food and the concept of 'food addiction': Is stimulation of the brain reward circuit by food sufficient to trigger addiction?

    PubMed

    Onaolapo, A Y; Onaolapo, O J

    2018-04-12

    In the last few years, the concept of 'food addiction' has continued to gain popularity, with human and animal studies demonstrating the differential effects of foods that are high in fat, sugar or protein on appetite, satiety, eating behaviour and the development of food addiction. However, a number of studies have disputed the occurrence of food addiction in humans. Questions have also arisen regarding the possible impacts that food additives may have on the development of food addiction or eating disorders. Also, it is known that alterations in food composition and the presence of food additives (flavour enhancers, sugars, sugar substitutes, and non-nutritive sweeteners) are factors that generally influence the sensory perception of food. Our understanding of the potential roles of central neurotransmitters (such as dopamine) and certain neuropeptides in the evolution of food addiction is also evolving; but presently, there isn't sufficient scientific evidence to consider any food ingredient, micronutrient or standard food-additive as addictive. In this review, the relevant literatures dealing with the concept of 'food addiction' are examined, and the factors which may predispose to food addiction are discussed. The possible influences that flavour-enhancers, sugars, sugar substitutes and non-nutritive sweeteners may exert on central neurotransmission, neurotransmitter/receptor interactions, appetite, satiety, conditioned- preferences and the brain reward system are also highlighted. Copyright © 2018 Elsevier B.V. All rights reserved.

  20. Healthy food access for urban food desert residents: examination of the food environment, food purchasing practices, diet and BMI.

    PubMed

    Dubowitz, Tamara; Zenk, Shannon N; Ghosh-Dastidar, Bonnie; Cohen, Deborah A; Beckman, Robin; Hunter, Gerald; Steiner, Elizabeth D; Collins, Rebecca L

    2015-08-01

    To provide a richer understanding of food access and purchasing practices among US urban food desert residents and their association with diet and BMI. Data on food purchasing practices, dietary intake, height and weight from the primary food shopper in randomly selected households (n 1372) were collected. Audits of all neighbourhood food stores (n 24) and the most-frequented stores outside the neighbourhood (n 16) were conducted. Aspects of food access and purchasing practices and relationships among them were examined and tests of their associations with dietary quality and BMI were conducted. Two low-income, predominantly African-American neighbourhoods with limited access to healthy food in Pittsburgh, PA, USA. Household food shoppers. Only one neighbourhood outlet sold fresh produce; nearly all respondents did major food shopping outside the neighbourhood. Although the nearest full-service supermarket was an average of 2·6 km from their home, respondents shopped an average of 6·0 km from home. The average trip was by car, took approximately 2 h for the round trip, and occurred two to four times per month. Respondents spent approximately $US 37 per person per week on food. Those who made longer trips had access to cars, shopped less often and spent less money per person. Those who travelled further when they shopped had higher BMI, but most residents already shopped where healthy foods were available, and physical distance from full-service supermarkets was unrelated to weight or dietary quality. Improved access to healthy foods is the target of current policies meant to improve health. However, distance to the closest supermarket might not be as important as previously thought, and thus policy and interventions that focus merely on improving access may not be effective.

  1. Nanotechnology for Food Packaging and Food Quality Assessment.

    PubMed

    Rossi, Marco; Passeri, Daniele; Sinibaldi, Alberto; Angjellari, Mariglen; Tamburri, Emanuela; Sorbo, Angela; Carata, Elisabetta; Dini, Luciana

    Nanotechnology has paved the way to innovative food packaging materials and analytical methods to provide the consumers with healthier food and to reduce the ecological footprint of the whole food chain. Combining antimicrobial and antifouling properties, thermal and mechanical protection, oxygen and moisture barrier, as well as to verify the actual quality of food, e.g., sensors to detect spoilage, bacterial growth, and to monitor incorrect storage conditions, or anticounterfeiting devices in food packages may extend the products shelf life and ensure higher quality of foods. Also the ecological footprint of food chain can be reduced by developing new completely recyclable and/or biodegradable packages from natural and eco-friendly resources. The contribution of nanotechnologies to these goals is reviewed in this chapter, together with a description of portable devices ("lab-on-chip," sensors, nanobalances, etc.) which can be used to assess the quality of food and an overview of regulations in force on food contact materials. © 2017 Elsevier Inc. All rights reserved.

  2. Characteristics of fast-food/takeaway-food and restaurant/café-food consumers among New Zealand adults.

    PubMed

    Smith, Claire; Gray, Andrew Robert; Fleming, Elizabeth Ann; Parnell, Winsome Ruth

    2014-10-01

    To investigate: (i) the percentage of the New Zealand (NZ) population reporting fast food/takeaway food and restaurant/café food per day; (ii) examine demographic factors associated with their use; (iii) quantify their contribution to energy intake; and (iv) describe the specific types of foods reported from both sources. Twenty-four hour diet recalls from the cross-sectional 2008/09 NZ Adult Nutrition Survey were used to identify fast-food and restaurant-food consumers. NZ households. Adults aged 15 years and older (n 4721). Overall 28 % reported consuming at least one fast food and 14 % a restaurant food within the 24 h diet recall. Fast-food consumption was not associated with level of education or an area-based measure of socio-economic status, but a higher education was positively associated with restaurant-food consumption. Individual factors such as ethnicity, household size, age, sex and marital status were found to be important influences on the use of fast food and restaurant food. Fast-food consumption was more prevalent among participants living in urban areas, young adults (19-30 years) and Māori compared with NZ European and Others. The most frequently reported fast foods were bread-based dishes, potatoes (including fries) and non-alcoholic beverages. Given the high reported consumption of fast food by young adults, health promotion initiatives both to improve the nutritional quality of fast-food menus and to encourage healthier food choices would likely make a large impact on the overall diet quality of this group.

  3. Who regulates food? Australians' perceptions of responsibility for food safety.

    PubMed

    Henderson, Julie; Coveney, John; Ward, Paul

    2010-01-01

    Food scares have diminished trust in public institutions to guarantee food safety. Food governance after the food scare era is concerned with institutional independence and transparency leading to a hybrid of public and private sector management and to mechanisms for consumer involvement in food governance. This paper explores Australian consumers' perceptions of who is, and should be responsible for food safety. Forty-seven participants were interviewed as part of a larger study on trust in the food system. Participants associate food governance with government, industry, and the individual. While few participants can name the national food regulator, there is a strong belief that the government is responsible for regulating the quality and safety of food. Participants are wary of the role of the food industry in food safety, believing that profit motives will undermine effective food regulation. Personal responsibility for food safety practices was also identified. While there are fewer mechanisms for consumer involvement and transparency built into the food governance system, Australian consumers display considerable trust in government to protect food safety. There is little evidence of the politicisation of food, reflecting a level of trust in the Australian food governance system that may arise from a lack of exposure to major food scares.

  4. An investigation of maternal food intake and maternal food talk as predictors of child food intake.

    PubMed

    DeJesus, Jasmine M; Gelman, Susan A; Viechnicki, Gail B; Appugliese, Danielle P; Miller, Alison L; Rosenblum, Katherine L; Lumeng, Julie C

    2018-08-01

    Though parental modeling is thought to play a critical role in promoting children's healthy eating, little research has examined maternal food intake and maternal food talk as independent predictors of children's food intake. The present study examines maternal food talk during a structured eating protocol, in which mothers and their children had the opportunity to eat a series of familiar and unfamiliar vegetables and desserts. Several aspects of maternal talk during the protocol were coded, including overall food talk, directives, pronoun use, and questions. This study analyzed the predictors of maternal food talk and whether maternal food talk and maternal food intake predicted children's food intake during the protocol. Higher maternal body mass index (BMI) predicted lower amounts of food talk, pronoun use, and questions. Higher child BMI z-scores predicted more first person pronouns and more wh-questions within maternal food talk. Mothers of older children used fewer directives, fewer second person pronouns, and fewer yes/no questions. However, maternal food talk (overall and specific types of food talk) did not predict children's food intake. Instead, the most robust predictor of children's food intake during this protocol was the amount of food that mothers ate while sitting with their children. These findings emphasize the importance of modeling healthy eating through action and have implications for designing interventions to provide parents with more effective tools to promote their children's healthy eating. Copyright © 2018 Elsevier Ltd. All rights reserved.

  5. Validation of WRF-Chem air quality simulations in the Netherlands at high resolution

    NASA Astrophysics Data System (ADS)

    Hilboll, A.; Lowe, D.; Kuenen, J. J. P.; Denier Van Der Gon, H.; Vrekoussis, M.

    2017-12-01

    Air pollution is the single most important environmental hazard for publichealth, and especially nitrogen dioxide (NO2) plays a key role in air qualityresearch. With the aim of improving the quality and reproducibility ofmeasurements of NO2 vertical distribution from MAX-DOAS instruments, theCINDI-2 campaign was held in Cabauw (NL) in September 2016.The measurement site was rural, but surrounded by several major pollutioncenters. Due to this spatial heterogeneity of emissions, as well as themeteorological conditions, high spatial and temporal variability in NO2 mixingratios were observed.Air quality models used in the analysis of the measured data must have highspatial resolution in order to resolve this fine spatial structure. Thisremains a challenge even today, mostly due to the uncertainties and largespatial heterogeneity of emission data, and the need to parameterize small-scaleprocesses.In this study, we use the state-of-the-art version 3.9 of the Weather Researchand Forecasting Model with Chemistry (WRF-Chem) to simulate air pollutantconcentrations over the Netherlands, to facilitate the analysis of the CINDI-2NO2 measurements. The model setup contains three nested domains withhorizontal resolutions of 15, 3, and 1 km. Anthropogenic emissions are takenfrom the TNO-MACC III inventory and, where available, from the Dutch PollutantRelease and Transfer Register (Emissieregistratie), at a spatial resolution of 7and 1 km, respectively. We use the Common Reactive Intermediates gas-phasechemical mechanism (CRIv2-R5) with the MOSAIC aerosol module.The high spatial resolution of model and emissions will allow us to resolve thestrong spatial gradients in the NO2 concentrations measured during theCINDI-2 campaign, allowing for an unprecedented level of detail in theanalysis of individual pollution sources.

  6. Food waste reduction practices in German food retail.

    PubMed

    Hermsdorf, David; Rombach, Meike; Bitsch, Vera

    2017-01-01

    The purpose of this paper is to investigate food retailers food waste reduction practices in Germany. The focus is on selling and redistributing agricultural produce with visual impairments and other surplus food items. In addition, drivers and barriers regarding the implementation of both waste reduction practices are explored. In total, 12 in-depth interviews with managerial actors in the food retail sector and a food bank spokesperson were recorded, transcribed and analyzed through a qualitative content analysis. In contrast to organic retailers, conventional retailers were reluctant to include agricultural produce with visual impairments in their product assortments, due to fears of negative consumer reactions. Another obstacle was EU marketing standards for specific produce. All retailers interviewed engaged in redistribution of surplus food. Logistics and the regulatory framework were the main barriers to food redistribution. The present study adds to the existing body of literature on food waste reduction practices as it explores selling produce with visual impairments and elaborates on the legal background of food redistribution in German retail. The results are the foundation for providing recommendations to policy makers and charitable food organizations.

  7. Radiative effects of black carbon aerosols on Indian monsoon: a study using WRF-Chem model

    NASA Astrophysics Data System (ADS)

    Soni, Pramod; Tripathi, Sachchida Nand; Srivastava, Rajesh

    2018-04-01

    The Weather Research and Forecasting model with Chemistry (WRF-Chem) is utilized to examine the radiative effects of black carbon (BC) aerosols on the Indian monsoon, for the year 2010. Five ensemble simulations with different initial conditions (1st to 5th December, 2009) were performed and simulation results between 1st January, 2010 to 31st December, 2010 were used for analysis. Most of the BC which stays near the surface during the pre-monsoon season gets transported to higher altitudes with the northward migration of the Inter Tropical Convergence Zone (ITCZ) during the monsoon season. In both the seasons, strong negative SW anomalies are present at the surface along with positive anomalies in the atmosphere, which results in the surface cooling and lower tropospheric heating, respectively. During the pre-monsoon season, lower troposphere heating causes increased convection and enhanced meridional wind circulation, bringing moist air from Indian Ocean and Bay of Bengal to the North-East India, leading to increased rainfall there. However, during the monsoon season, along with cooling over the land regions, a warming over the Bay of Bengal is simulated. This differential heating results in an increased westerly moisture flux anomaly over central India, leading to increased rainfall over northern parts of India but decreased rainfall over southern parts. Decreased rainfall over southern India is also substantiated by the presence of increased evaporation over Bay of Bengal and decrease over land regions.

  8. Differentiating food allergies from food intolerances.

    PubMed

    Guandalini, Stefano; Newland, Catherine

    2011-10-01

    Adverse reactions to foods are extremely common, and generally they are attributed to allergy. However, clinical manifestations of various degrees of severity related to ingestion of foods can arise as a result of a number of disorders, only some of which can be defined as allergic, implying an immune mechanism. Recent epidemiological data in North America showed that the prevalence of food allergy in children has increased. The most common food allergens in the United States include egg, milk, peanut, tree nuts, wheat, crustacean shellfish, and soy. This review examines the various forms of food intolerances (immunoglobulin E [IgE] and non-IgE mediated), including celiac disease and gluten sensitivity. Immune mediated reactions can be either IgE mediated or non-IgE mediated. Among the first group, Immediate GI hypersensitivity and oral allergy syndrome are the best described. Often, but not always, IgE-mediated food allergies are entities such as eosinophilic esophagitis and eosinophilic gastroenteropathy. Non IgE-mediated immune mediated food reactions include celiac disease and gluten sensitivity, two increasingly recognized disorders. Finally, non-immune mediated reactions encompass different categories such as disorders of digestion and absorption, inborn errors of metabolism, as well as pharmacological and toxic reactions.

  9. Characterization of bacterial diversity at different depths in the Moravia Hill landfill site at Medellin, Colombia

    USDA-ARS?s Scientific Manuscript database

    A combination of culture-dependent and culture-independent methods was used to assess bacterial diversity at different depths within a former solid waste dump in Medellín, Colombia. Sampling sites included a densely populated area, which is built upon 40 m of solid waste (domestic, industrial, agric...

  10. Effect of Atmospheric Conditions on Coverage of Fogger Applications in a Desert Surface Boundary Layer

    DTIC Science & Technology

    2012-01-01

    2007) in pecan orchards, among others. In this sparse shrub desert environment, Nappo et al. (2010) showed that, during sta- ble conditions, the...measuring water use in flood-irrigated pecans (Carya illinoinensis). Agric. Water Mgmt. 88(1-3): 181-191. Solanelles, F., E. Gregorio, R. Sanz, J. R

  11. The potential of food preservation to reduce food waste.

    PubMed

    Martindale, Wayne

    2017-02-01

    While we state it seems unthinkable to throw away nearly a third of the food we produce, we still continue to overlook that we are all very much part of this problem because we all consume meals. The amount of food wasted clearly has an impact on our view of what we think a sustainable meal is and our research suggests food waste is a universal function that can help us determine the sustainability of diets. Achieving sustainability in food systems depends on the utilisation of both culinary skills and knowledge of how foods make meals. These are overlooked by the current food waste debate that is concerned with communicating the problem with food waste rather than solutions to it. We aim to change this oversight with the research presented here that demonstrates the need to consider the role of food preservation to reduce food waste and the requirement for new marketing terms associated with sustainability actions that can be used to stimulate changes in consumption behaviours. We have chosen frozen food to demonstrate this because our research has shown that the use of frozen foods results in 47 % less household food waste than fresh food categories. This has created a step-change in how we view food consumption and has stimulated consumer movements that act across different products and supply chains to enable the consumption of the sustainable meal.

  12. Food provision among food relief agencies in rural Australia, and perceived barriers and enablers to provide healthy food.

    PubMed

    Bortolin, Natalia; Priestly, Jaqueline; Sangster, Janice

    2018-04-01

    Food insecurity affects 4-14% of Australians, and up to 82% of vulnerable groups. Food relief agencies commonly provide food parcels or food vouchers. Little research has been undertaken on food relief agencies within rural Australia. This study determined the type of food assistance provided by rural food relief agencies, and barriers and enablers to provide healthy food. Cross-sectional study, using telephone questionnaires with qualitative and quantitative aspects. Data were analysed using descriptive statistics and thematic analysis. Rural New South Wales, Australia. Representatives of 10 food relief agencies. Types of food assistance and food provided, and the barriers and enablers to provide healthy food to clients. Most agencies provided food hampers and perishable and non-perishable food. Rural food relief agencies had a greater capacity to provide non-perishable compared to perishable food. Grains, breads and cereals, and canned fruit and vegetables were most popular. Nine key themes emerged including 'Ability to purchase and provide healthy food', 'Ability to regulate food purchased or chosen by clients', 'Financial constraints of the agency' and 'Lack of storage'. There are many variables to consider in order to understand the capacity of rural food relief agencies to provide healthy food. There are also opportunities for food relief agencies to appraise current practices and make changes. Initiatives to improve storage facilities and food availability are key and include networking with local businesses, community organisations and government. Rural food relief agency clients could benefit from accessing food literacy and health programs like FoodREDi, OzHarvest NEST and SecondBite Fresh NED. © 2017 National Rural Health Alliance Inc.

  13. Food hygiene and safety measures among food handlers in street food shops and food establishments of Dessie town, Ethiopia: A community-based cross-sectional study.

    PubMed

    Adane, Metadel; Teka, Brhanu; Gismu, Yirga; Halefom, Goitom; Ademe, Muluneh

    2018-01-01

    In sub-Saharan Africa foodborne disease and foodborne disease outbreaks are frequently ascribed to poor personal hygiene of street food vendors and food handlers in food establishments. Evidence on the level of food hygiene practices and food safety measures among food handlers is required for proper planning and implementation of targeted interventions. In this study, we aimed to determine the level of food hygiene and safety measures among street food vendors and food handlers in food establishments of Dessie Town, Ethiopia. A community-based cross-sectional study was performed in Dessie town, Ethiopia from December 2013 to June 2014. Data were collected using a pre-tested structured questionnaire and an observational checklist by a trained data collector among 116 food handlers from 116 food establishments and 19 food handlers from 19 street food vendors. Multivariable logistic regression analysis with 95% confidence interval (CI) was used to identify the factors significantly associated with good level of food hygiene and safety practices. Almost three-quarter (72%; 84/116) of food handlers in food establishments had a good level of food hygiene and safety practices compared to nearly half (53%; 10/19) of street food vendors. However, this difference was not statistically significant. Average monthly income of >$21 US (adjusted odds ratio [AOR] = 3.2; 95%CI: 1.3-7.7), availability of service training (AOR = 6.7; 95%CI: 1.8-25), wearing a gown during food handling (AOR = 19; 95%CI: 6.8-51) and medical checkup (AOR = 5.2; 95%CI: 2.1-13) were significantly associated with good levels of food hygiene and safety measures. Comprehensive health education and promotion programs through continuous training on food hygiene and safety, with promotion of wearing gown during food handling, regular medical checkups of food handlers and programs that enhance the monthly income of food handlers are promising strategies for promoting proper food handling practices in Dessie

  14. Food hygiene and safety measures among food handlers in street food shops and food establishments of Dessie town, Ethiopia: A community-based cross-sectional study

    PubMed Central

    Adane, Metadel; Teka, Brhanu; Gismu, Yirga; Halefom, Goitom

    2018-01-01

    Introduction In sub-Saharan Africa foodborne disease and foodborne disease outbreaks are frequently ascribed to poor personal hygiene of street food vendors and food handlers in food establishments. Evidence on the level of food hygiene practices and food safety measures among food handlers is required for proper planning and implementation of targeted interventions. In this study, we aimed to determine the level of food hygiene and safety measures among street food vendors and food handlers in food establishments of Dessie Town, Ethiopia. Method A community-based cross-sectional study was performed in Dessie town, Ethiopia from December 2013 to June 2014. Data were collected using a pre-tested structured questionnaire and an observational checklist by a trained data collector among 116 food handlers from 116 food establishments and 19 food handlers from 19 street food vendors. Multivariable logistic regression analysis with 95% confidence interval (CI) was used to identify the factors significantly associated with good level of food hygiene and safety practices. Result Almost three-quarter (72%; 84/116) of food handlers in food establishments had a good level of food hygiene and safety practices compared to nearly half (53%; 10/19) of street food vendors. However, this difference was not statistically significant. Average monthly income of >$21 US (adjusted odds ratio [AOR] = 3.2; 95%CI: 1.3–7.7), availability of service training (AOR = 6.7; 95%CI: 1.8–25), wearing a gown during food handling (AOR = 19; 95%CI: 6.8–51) and medical checkup (AOR = 5.2; 95%CI: 2.1–13) were significantly associated with good levels of food hygiene and safety measures. Conclusion Comprehensive health education and promotion programs through continuous training on food hygiene and safety, with promotion of wearing gown during food handling, regular medical checkups of food handlers and programs that enhance the monthly income of food handlers are promising strategies for

  15. A WRF-Chem model study of the impact of VOCs emission of a huge petro-chemical industrial zone on the summertime ozone in Beijing, China

    NASA Astrophysics Data System (ADS)

    Wei, Wei; Lv, Zhao Feng; Li, Yue; Wang, Li Tao; Cheng, Shuiyuan; Liu, Huan

    2018-02-01

    In China, petro-chemical manufacturing plants generally gather in the particular industrial zone defined as PIZ in some cities, and distinctly influence the air quality of these cities for their massive VOCs emissions. This study aims to quantify the local and regional impacts of PIZ VOCs emission and its relevant reduction policy on the surface ozone based on WRF-Chem model, through the case study of Beijing. Firstly, the model simulation under the actual precursors' emissions over Beijing region for July 2010 is conducted and evaluated, which meteorological and chemical predictions both within the thresholds for satisfactory model performance. Then, according to simulated H2O2/HNO3 ratio, the nature of photochemical ozone formation over Beijing is decided, the VOCs-sensitive regime over the urban areas, NOx-sensitive regime over the northern and western rural areas, and both VOCssbnd and NOx-mixed sensitive regime over the southern and eastern rural areas. Finally, a 30% VOCs reduction scenario (RS) and a 100% VOCs reduction scenario (ZS) for Beijing PIZ are additional simulated by WRF-Chem. The sensitivity simulations imply that the current 30% reduction policy would bring about an O3 increase in the southern and western areas (by +4.7 ppb at PIZ site and +2.1 ppb at LLH station), and an O3 decrease in the urban center (by -1.7 ppb at GY station and -2.5 ppb at DS station) and in the northern and eastern areas (by -1.2 ppb at MYX station), mainly through interfering with the circulation of atmospheric HOx radicals. While the contribution of the total VOCs emission of PIZ to ozone is greatly prominent in the PIZ and its surrounding areas along south-north direction (12.7% at PIZ site on average), but slight in the other areas of Beijing (<3% in other four stations on average).

  16. Hydrostatic, uniaxial, and triaxial compression tests on unpoled "Chem-prep" PZT 95/5-2Nb ceramic within temperature range of -55 to 75 degrees C.

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zeuch, David Henry; Montgomery, Stephen Tedford; Lee, Moo Yul

    Sandia is currently developing a lead-zirconate-titanate ceramic 95/5-2Nb (or PNZT) from chemically prepared ('chem-prep') precursor powders. Previous PNZT ceramic was fabricated from the powders prepared using a 'mixed-oxide' process. The specimens of unpoled PNZT ceramic from batch HF803 were tested under hydrostatic, uniaxial, and constant stress difference loading conditions within the temperature range of -55 to 75 C and pressures to 500 MPa. The objective of this experimental study was to obtain mechanical properties and phase relationships so that the grain-scale modeling effort can develop and test its models and codes using realistic parameters. The stress-strain behavior of 'chem-prep' PNZTmore » under different loading paths was found to be similar to that of 'mixed-oxide' PNZT. The phase transformation from ferroelectric to antiferroelectric occurs in unpoled ceramic with abrupt increase in volumetric strain of about 0.7 % when the maximum compressive stress, regardless of loading paths, equals the hydrostatic pressure at which the transformation otherwise takes place. The stress-volumetric strain relationship of the ceramic undergoing a phase transformation was analyzed quantitatively using a linear regression analysis. The pressure (P{sub T1}{sup H}) required for the onset of phase transformation with respect to temperature is represented by the best-fit line, P{sub T1}{sup H} (MPa) = 227 + 0.76 T (C). We also confirmed that increasing shear stress lowers the mean stress and the volumetric strain required to trigger phase transformation. At the lower bound (-55 C) of the tested temperature range, the phase transformation is permanent and irreversible. However, at the upper bound (75 C), the phase transformation is completely reversible as the stress causing phase transformation is removed.« less

  17. Food group adherence scores assess food patterns compared to US Department of Agriculture Food Guide.

    PubMed

    Knol, Linda L; Haughton, Betsy; Fitzhugh, Eugene C

    2006-08-01

    The purpose of this study was twofold: (a) develop and test the potential usefulness of a new measure of dietary adherence to the US Department of Agriculture (USDA) Food Guide and (b) use this measure to assess the diets of children in the United States. Using 2 days of food intake data from the 1994-1996, 1998 Continuing Survey of Food Intakes by Individuals, food group adherence scores for individual food groups were calculated based on intake and recommendations from the USDA Food Guide. Two samples of children, age 2 to 3 years (n=2,815) and 4 to 8 years (n=3,769), were selected from the 1994-1996, 1998 Continuing Survey of Food Intakes by Individuals. Descriptive statistics were computed by age and sex. Linear regression analysis was used to detect significant differences in adherence scores and number of servings consumed between age groups after adjusting for factors that impact intake. Comparing the two age groups, differences in the food group adherence scores for some food groups did not mimic the differences seen in mean number of servings from the same food group. For these two age groups of children, although the number of servings from the food groups significantly increased with increasing age, the adherence scores significantly decreased, reflecting decreased adherence to the recommended food patterns by age. Results suggest adherence to the USDA Food Guide decreases with increasing age in young children in the United States. Adherence scores may be a useful tool to describe adherence to the new USDA Food Guide. These scores could be used in program evaluation, surveillance, and epidemiological studies of diet and health.

  18. Food colors: Existing and emerging food safety concerns.

    PubMed

    Oplatowska-Stachowiak, Michalina; Elliott, Christopher T

    2017-02-11

    Food colors are added to different types of commodities to increase their visual attractiveness or to compensate for natural color variations. The use of these additives is strictly regulated in the European Union, the United States, and many other countries worldwide. There is a growing concern about the safety of some commonly used legal food colorants and there is a trend to replace the synthetic forms with natural products. Additionally, a number of dyes with known or suspected genotoxic or carcinogenic properties have been shown to be added illegally to foods. Robust monitoring programs based on reliable detection methods are required to assure the food is free from harmful colors. The aim of this review is to present an up to date status of the various concerns arising from use of color additives in food. The most important food safety concerns in the field of food colors are lack of uniform regulation concerning legal food colors worldwide, possible link of artificial colors to hyperactive behavior, replacement of synthetic colors with natural ones, and the presence of harmful illegal dyes-both known but also new, emerging ones in food. The legal status of food color additives in the EU, United States, and worldwide is summarized. The reported negative health effects of both legal and illegal colors are presented. The European Rapid Alert System for Food and Feed notifications and US import alerts concerning food colors are analyzed and trends in fraudulent use of color additives identified. The detection methods for synthetic colors are also reviewed.

  19. Food Allergy

    MedlinePlus

    ... Home ▸ Conditions & Treatments ▸ Allergies ▸ Food Allergy Share | Food Allergy Overview Symptoms & Diagnosis Treatment & Management Food Allergy Overview If you have a food allergy, your ...

  20. Examining the interaction between food outlets and outdoor food advertisements with primary school food environments.

    PubMed

    Walton, Mat; Pearce, Jamie; Day, Peter

    2009-09-01

    Schools are commonly seen as a site of intervention to improve children's nutrition, and prevent excess weight gain. Schools may have limited influence over children's diets; however, with home and community environments also exerting an influence within schools. This study considered the environment of food outlets and outdoor food advertisements surrounding four case study primary schools in New Zealand, and the impact of that external environment on within-school food environments. The shortest travel route between school and home addresses, and the number of food outlets and advertisements passed on that route, was calculated for each student. Interviews with school management were conducted. The schools with a higher percentage of students passing food outlets and advertisements considered that their presence impacted on efforts within schools to improve the food environment. Limiting students' exposure to food outlets and outdoor food adverts through travel route planning, reducing advertising, or limiting the location of food outlets surrounding schools could be explored as intervention options to support schools in promoting nutrition.

  1. Instrumental Analysis in the High School Classroom: UV-Vis Spectroscopy

    ERIC Educational Resources Information Center

    Erhardt, Walt

    2007-01-01

    Note is presented on the standard lab from a second year chemistry course. The lab "Determining which of the Seven FD&C Food-Approved Dyes are Used in Making Green Skittles", familiarizes students with the operation of the CHEM2000 UV-Vis spectrophorometer.

  2. Food production & availability--essential prerequisites for sustainable food security.

    PubMed

    Swaminathan, M S; Bhavani, R V

    2013-09-01

    Food and nutrition security are intimately interconnected, since only a food based approach can help in overcoming malnutrition in an economically and socially sustainable manner. Food production provides the base for food security as it is a key determinant of food availability. This paper deals with different aspects of ensuring high productivity and production without associated ecological harm for ensuring adequate food availability. By mainstreaming ecological considerations in technology development and dissemination, we can enter an era of evergreen revolution and sustainable food and nutrition security. Public policy support is crucial for enabling this.

  3. Modeling regional air quality and climate: improving organic aerosol and aerosol activation processes in WRF/Chem version 3.7.1

    NASA Astrophysics Data System (ADS)

    Yahya, Khairunnisa; Glotfelty, Timothy; Wang, Kai; Zhang, Yang; Nenes, Athanasios

    2017-06-01

    Air quality and climate influence each other through the uncertain processes of aerosol formation and cloud droplet activation. In this study, both processes are improved in the Weather, Research and Forecasting model with Chemistry (WRF/Chem) version 3.7.1. The existing Volatility Basis Set (VBS) treatments for organic aerosol (OA) formation in WRF/Chem are improved by considering the following: the secondary OA (SOA) formation from semi-volatile primary organic aerosol (POA), a semi-empirical formulation for the enthalpy of vaporization of SOA, and functionalization and fragmentation reactions for multiple generations of products from the oxidation of VOCs. Over the continental US, 2-month-long simulations (May to June 2010) are conducted and results are evaluated against surface and aircraft observations during the Nexus of Air Quality and Climate Change (CalNex) campaign. Among all the configurations considered, the best performance is found for the simulation with the 2005 Carbon Bond mechanism (CB05) and the VBS SOA module with semivolatile POA treatment, 25 % fragmentation, and the emissions of semi-volatile and intermediate volatile organic compounds being 3 times the original POA emissions. Among the three gas-phase mechanisms (CB05, CB6, and SAPRC07) used, CB05 gives the best performance for surface ozone and PM2. 5 concentrations. Differences in SOA predictions are larger for the simulations with different VBS treatments (e.g., nonvolatile POA versus semivolatile POA) compared to the simulations with different gas-phase mechanisms. Compared to the simulation with CB05 and the default SOA module, the simulations with the VBS treatment improve cloud droplet number concentration (CDNC) predictions (normalized mean biases from -40.8 % to a range of -34.6 to -27.7 %), with large differences between CB05-CB6 and SAPRC07 due to large differences in their OH and HO2 predictions. An advanced aerosol activation parameterization based on the Fountoukis and Nenes

  4. Evaluation of aerosol optical properties of GEOS-Chem over East Asia during the DRAGON-Asia 2012 campaign

    NASA Astrophysics Data System (ADS)

    Jo, D. S.; Park, R.; Kim, J.

    2015-12-01

    A nested version of 3-D chemical transport model (GEOS-Chem v9-01-02) is evaluated over East Asia during the Distributed Regional Aerosol Gridded Observation Networks (DRAGON)-Asia 2012 campaign period, focusing on fine-mode aerosol optical depth (fAOD) and single scattering albedo (SSA). Both are important to assess the effect of anthropogenic aerosols on climate. We compare the daily mean simulated optical properties of aerosols with the observations from DRAGON-Asia campaign for March-May, 2012 (provided in level 2.0: cloud screened and quality assured). We find that the model reproduces the observed daily variability of fAOD (R=0.67), but overestimates the magnitude by 30%, which is in general consistent with other global model comparisons from ACCMIP. However, a significant high bias in the model is found compared to the observed SSA at 440 nm, which is important for determining the sign of aerosol radiative forcing. In order to understand causes for this gap we conduct several sensitivity tests by changing source magnitudes and input parameters of aerosols, affecting the aerosol optical properties under various atmospheric conditions, which allows us to reduce the gap and to find the optimal values in the model.

  5. Cross-contamination of foods and implications for food allergic patients.

    PubMed

    Taylor, Steve L; Baumert, Joseph L

    2010-07-01

    Cross-contamination presents a risk of unknown magnitude for food allergic consumers. Published cases likely represent the tip of a rather large iceberg. Cross-contamination can occur in homes, restaurants, food manufacturing plants, and on farms. The frequency of cross-contamination as the cause of accidental exposures to allergenic foods is unknown. Food allergic individuals can react to ingestion of trace levels of the offending food, although a highly variable range of threshold doses exist among populations of food allergic individuals. The magnitude of the risk posed to food allergic consumers by cross-contamination is characterized by the frequency of exposure to cross-contaminated foods, the dose of exposure, and the individual's threshold dose. The food and food service industry (and food preparers in homes as well) have the responsibility to provide and prepare foods that are safe for food allergic consumers, but quality of life may be improved with the recognition that safe (though very low) thresholds do exist.

  6. Food loss rate in food supply chain using material flow analysis.

    PubMed

    Ju, Munsol; Osako, Masahiro; Harashina, Sachihiko

    2017-03-01

    The food loss rate is a factor that represents food consumption efficiency. To improve food consumption efficiency, we need to fundamentally quantify food loss at national and global levels. This study examines food and food waste flow and calculates the food loss rate in the food supply chain by targeting Japan. We analyzed inedible food waste and avoidable food losses in wholesale, manufacturing, retail, food services, and households and considered different supply chain pathways, different food categories representing whole Japanese meals, and weight changes after cooking. The results are as follows: (1) Japan has an overall rate of avoidable food losses of approximately 15% for meals (excluding agricultural losses), (2) the supply sector with the highest food loss rate is food services, and (3) the food category with the highest food loss rate is vegetables. Finally, we proposed a model for calculating food loss rates that could be used for future analysis in Japan or other countries. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Food insecurity and diabetes self-management among food pantry clients.

    PubMed

    Ippolito, Matthew M; Lyles, Courtney R; Prendergast, Kimberly; Marshall, Michelle Berger; Waxman, Elaine; Seligman, Hilary Kessler

    2017-01-01

    To examine the association between level of food security and diabetes self-management among food pantry clients, which is largely not possible using clinic-based sampling methods. Cross-sectional descriptive study. Community-based food pantries in California, Ohio and Texas, USA, from March 2012 through March 2014. Convenience sample of adults with diabetes queuing at pantries (n 1237; 83 % response). Sampled adults were stratified as food secure, low food secure or very low food secure. We used point-of-care glycated Hb (HbA1c) testing to determine glycaemic control and captured diabetes self-management using validated survey items. The sample was 70 % female, 55 % Latino/Hispanic, 25 % white and 10 % black/African American, with a mean age of 56 years. Eighty-four per cent were food insecure, one-half of whom had very low food security. Mean HbA1c was 8·1 % and did not vary significantly by food security status. In adjusted models, very-low-food-secure participants, compared with both low-food-secure and food-secure participants, had poorer diabetes self-efficacy, greater diabetes distress, greater medication non-adherence, higher prevalence of severe hypoglycaemic episodes, higher prevalence of depressive symptoms, more medication affordability challenges, and more food and medicine or health supply trade-offs. Few studies of the health impact of food security have been able to examine very low food security. In a food pantry sample with high rates of food insecurity, we found that diabetes self-management becomes increasingly difficult as food security worsens. The efficacy of interventions to improve diabetes self-management may increase if food security is simultaneously addressed.

  8. Evaluating North Carolina Food Pantry Food Safety-Related Operating Procedures.

    PubMed

    Chaifetz, Ashley; Chapman, Benjamin

    2015-11-01

    Almost one in seven American households were food insecure in 2012, experiencing difficulty in providing enough food for all family members due to a lack of resources. Food pantries assist a food-insecure population through emergency food provision, but there is a paucity of information on the food safety-related operating procedures used in the pantries. Food pantries operate in a variable regulatory landscape; in some jurisdictions, they are treated equivalent to restaurants, while in others, they operate outside of inspection regimes. By using a mixed methods approach to catalog the standard operating procedures related to food in 105 food pantries from 12 North Carolina counties, we evaluated their potential impact on food safety. Data collected through interviews with pantry managers were supplemented with observed food safety practices scored against a modified version of the North Carolina Food Establishment Inspection Report. Pantries partnered with organized food bank networks were compared with those that operated independently. In this exploratory research, additional comparisons were examined for pantries in metropolitan areas versus nonmetropolitan areas and pantries with managers who had received food safety training versus managers who had not. The results provide a snapshot of how North Carolina food pantries operate and document risk mitigation strategies for foodborne illness for the vulnerable populations they serve. Data analysis reveals gaps in food safety knowledge and practice, indicating that pantries would benefit from more effective food safety training, especially focusing on formalizing risk management strategies. In addition, new tools, procedures, or policy interventions might improve information actualization by food pantry personnel.

  9. Identifying rural food deserts: Methodological considerations for food environment interventions.

    PubMed

    Lebel, Alexandre; Noreau, David; Tremblay, Lucie; Oberlé, Céline; Girard-Gadreau, Maurie; Duguay, Mathieu; Block, Jason P

    2016-06-09

    Food insecurity in an important public health issue and affects 13% of Canadian households. It is associated with poor accessibility to fresh, diverse and affordable food products. However, measurement of the food environment is challenging in rural settings since the proximity of food supply sources is unevenly distributed. The objective of this study was to develop a methodology to identify food deserts in rural environments. In-store evaluations of 25 food products were performed for all food stores located in four contiguous rural counties in Quebec. The quality of food products was estimated using four indices: freshness, affordability, diversity and the relative availability. Road network distance between all residences to the closest food store with a favourable score on the four dimensions was mapped to identify residential clusters located in deprived communities without reasonable access to a "good" food source. The result was compared with the food desert parameters proposed by the US Department of Agriculture (USDA), as well as with the perceptions of a group of regional stakeholders. When food quality was considered, food deserts appeared more prevalent than when only the USDA definition was used. Objective measurements of the food environment matched stakeholders' perceptions. Food stores' characteristics are different in rural areas and require an in-store estimation to identify potential rural food deserts. The objective measurements of the food environment combined with the field knowledge of stakeholders may help to shape stronger arguments to gain the support of decision-makers to develop relevant interventions.

  10. Food production & availability - Essential prerequisites for sustainable food security

    PubMed Central

    Swaminathan, M.S.; Bhavani, R.V.

    2013-01-01

    Food and nutrition security are intimately interconnected, since only a food based approach can help in overcoming malnutrition in an economically and socially sustainable manner. Food production provides the base for food security as it is a key determinant of food availability. This paper deals with different aspects of ensuring high productivity and production without associated ecological harm for ensuring adequate food availability. By mainstreaming ecological considerations in technology development and dissemination, we can enter an era of evergreen revolution and sustainable food and nutrition security. Public policy support is crucial for enabling this. PMID:24135188

  11. Food Safety-Related Aspects of Parasites in Foods.

    PubMed

    Watthanakulpanich, Dorn

    2015-01-01

    As natural foods derive from soil or water environments, they may contain the infective stages of parasites endemic to these environments. Infective stages may enter the human food supply via infected animal hosts so there is a need for increased awareness of the impact of parasites on the food supply. Safe handling of food and good kitchen hygiene can prevent or reduce the risk posed by contaminated foodstuffs. In addition, parasites cannot cause a health problem in any thoroughly cooked foods.

  12. Current-use pesticides in seawater and their bioaccumulation in polar bear-ringed seal food chains of the Canadian Arctic.

    PubMed

    Morris, Adam D; Muir, Derek C G; Solomon, Keith R; Letcher, Robert J; McKinney, Melissa A; Fisk, Aaron T; McMeans, Bailey C; Tomy, Gregg T; Teixeira, Camilla; Wang, Xiaowa; Duric, Mark

    2016-07-01

    The distribution of current-use pesticides (CUPs) in seawater and their trophodynamics were investigated in 3 Canadian Arctic marine food chains. The greatest ranges of dissolved-phase concentrations in seawater for each CUP were endosulfan sulfate (less than method detection limit (MDL) to 19 pg L(-1) ) > dacthal (0.76-15 pg L(-1) ) > chlorpyrifos (less than MDL to 8.1 pg L(-1) ) > pentachloronitrobenzene (less than MDL to 2.6 pg L(-1) ) > α-endosulfan (0.20-2.3 pg L(-1) ). Bioaccumulation factors (BAFs, water-respiring organisms) were greatest in plankton, including chlorothalonil (log BAF = 7.4 ± 7.1 L kg(-1) , mean ± standard error), chlorpyrifos (log BAF = 6.9 ± 6.7 L kg(-1) ), and α-endosulfan (log BAF = 6.5 ± 6.0 L kg(-1) ). The largest biomagnification factors (BMFs) were found for dacthal in the capelin:plankton trophic relationship (BMF = 13 ± 5.0) at Cumberland Sound (Nunvavut), and for β-endosulfan (BMF = 16 ± 4.9) and α-endosulfan (BMF = 9.3 ± 2.8) in the polar bear-ringed seal relationship at Barrow and Rae Strait (NU), respectively. Concentrations of endosulfan sulfate exhibited trophic magnification (increasing concentrations with increasing trophic level) in the poikilothermic portion of the food web (trophic magnification factor = 1.4), but all of the CUPs underwent trophic dilution in the marine mammal food web, despite some trophic level-specific biomagnification. Together, these observations are most likely indicative of metabolism of these CUPs in mammals. Environ Toxicol Chem 2016;35:1695-1707. © 2016 SETAC. © 2016 SETAC.

  13. Evaluating optimum limited irrigation management strategies for corn production in the ogallala aquifer region

    USDA-ARS?s Scientific Manuscript database

    Water is the major factor limiting crop production in the Ogallala Aquifer Region of the U.S. Central High Plains. Seasonal precipitation is highly variable, low in amount, and not enough to meet full corn water needs. The Ogallala Aquifer is the major source of irrigation water for commercial agric...

  14. Food Allergies

    MedlinePlus

    ... Staying Safe Videos for Educators Search English Español Food Allergies KidsHealth / For Kids / Food Allergies What's in ... cow's milk eggs soy wheat What Is a Food Allergy? Food allergies happen when the immune system ...

  15. "Everyone just ate good food": 'Good food' in Islamabad, Pakistan.

    PubMed

    Hasnain, Saher

    2018-08-01

    In recent years, consumption of alternatively produced foods has increased in popularity in response to the deleterious effects of rapidly globalising and industrialised food systems. Concerns over food safety in relation to these changes may result from elevated levels of risk and changing perceptions associated with food production practices. This paper explores how the middle class residents of Islamabad, Pakistan, use the concept of 'good food' to reconnect themselves with nature, changing food systems, and traditional values. The paper also demonstrates how these ideas relate to those of organic, local, and traditional food consumption as currently used in more economically developed states in the Global North. Through research based on participant observation and semi-structured interviews, this paper illustrates that besides price and convenience, purity, freshness, association with specific places, and 'Pakistani-ness' were considered as the basis for making decisions about 'good food'. The results show that while individuals are aware of and have some access to imported organic and local food, they prefer using holistic and culturally informed concepts of 'good food' instead that reconnect them with food systems. I argue that through conceptualisations of 'good food', the urban middle class in Islamabad is reducing their disconnection and dis-embeddedness from nature, the food systems, and their social identities. The paper contributes to literature on food anxieties, reconnections in food geography, and 'good food' perceptions, with a focus on Pakistan. Copyright © 2018. Published by Elsevier Ltd.

  16. Food safety regulations in Australia and New Zealand Food Standards.

    PubMed

    Ghosh, Dilip

    2014-08-01

    Citizens of Australia and New Zealand recognise that food security is a major global issue. Food security also affects Australia and New Zealand's status as premier food exporting nations and the health and wellbeing of the Australasian population. Australia is uniquely positioned to help build a resilient food value chain and support programs aimed at addressing existing and emerging food security challenges. The Australian food governance system is fragmented and less transparent, being largely in the hands of government and semi-governmental regulatory authorities. The high level of consumer trust in Australian food governance suggests that this may be habitual and taken for granted, arising from a lack of negative experiences of food safety. In New Zealand the Ministry of Primary Industries regulates food safety issues. To improve trade and food safety, New Zealand and Australia work together through Food Standards Australia New Zealand (FSANZ) and other co-operative agreements. Although the potential risks to the food supply are dynamic and constantly changing, the demand, requirement and supply for providing safe food remains firm. The Australasian food industry will need to continually develop its system that supports the food safety program with the help of scientific investigations that underpin the assurance of what is and is not safe. The incorporation of a comprehensive and validated food safety program is one of the total quality management systems that will ensure that all areas of potential problems are being addressed by industry. © 2014 Society of Chemical Industry.

  17. Food Allergy

    MedlinePlus

    ... needed to confirm an allergy. Videos: Choosing Wisely » Food Allergy Treatment & Management Proper diagnosis of food allergy or food intolerance ... patient support. The Guidelines for the Diagnosis and Management of Food Allergy in the United States: Summary for Patients, ...

  18. Healthy food access for urban food desert residents: examination of the food environment, food purchasing practices, diet, and body mass index

    PubMed Central

    Dubowitz, Tamara; Zenk, Shannon N.; Ghosh-Dastidar, Bonnie; Cohen, Deborah; Beckman, Robin; Hunter, Gerald; Steiner, Elizabeth D.; Collins, Rebecca L.

    2015-01-01

    Objective Provide a richer understanding of food access and purchasing practices among U.S. urban food desert residents and their association with diet and body mass. Design Data on food purchasing practices, dietary intake, height, and weight from the primary food shopper in randomly selected households (n=1372) was collected. Audits of all neighborhood food stores (n=24) and the most-frequented stores outside the neighborhood (n=16) were conducted. Aspects of food access and purchasing practices and relationships among them were examined and tests of their associations with dietary quality and body mass index (BMI) were conducted. Setting Two low-income predominantly African-American neighborhoods with limited access to healthy food in Pittsburgh, Pennsylvania. Subjects Household food shoppers. Results Only one neighborhood outlet sold fresh produce; nearly all respondents did major food shopping outside the neighborhood. Although the nearest full-service supermarket was an average of 2.6 km from their home, respondents shopped an average of 6.0 km from home. The average trip was by car, took approximately two hours roundtrip, and occurred two to four times per month. Respondents spent approximately $37 per person per week on food. Those who made longer trips had access to cars, shopped less often, and spent less money per person. Those who traveled further when they shopped had higher BMIs, but most residents already shopped where healthy foods were available, and physical distance from full service groceries was unrelated to weight or dietary quality. Conclusions Improved access to healthy foods is the target of current policies meant to improve health. However, distance to the closest supermarket might not be as important as previously thought and thus policy and interventions that focus merely on improving access may not be effective. PMID:25475559

  19. Economic Impact of Food Safety Outbreaks on Food Businesses

    PubMed Central

    Hussain, Malik Altaf; Dawson, Christopher O.

    2013-01-01

    A globalized food trade, extensive production and complex supply chains are contributing toward an increased number of microbiological food safety outbreaks. Moreover, the volume of international food trade has increased to become very large. All of these factors are putting pressure on the food companies to meet global demand in order to be competitive. This scenario could force manufacturers to be lenient toward food safety control intentionally, or unintentionally, and result in a major foodborne outbreak that causes health problems and economic loss. The estimated cost of food safety incidents for the economy of the United States is around $7 billion per year which comes from notifying consumers, removing food from shelves, and paying damages as a result of lawsuits. Most other countries similarly have economic losses. Much of these losses represent lost markets, loss of consumer demand, litigation and company closures. Concrete steps are needed to improve safety of foods produced for local or overseas markets to avoid unexpected food scandals and economic losses. PMID:28239140

  20. Elements affecting food waste in the food service sector.

    PubMed

    Heikkilä, Lotta; Reinikainen, Anu; Katajajuuri, Juha-Matti; Silvennoinen, Kirsi; Hartikainen, Hanna

    2016-10-01

    Avoidable food waste is produced in the food service sector, with significant ecological and economical impacts. In order to understand and explain better the complex issue of food waste a qualitative study was conducted on the reasons for its generation in restaurants and catering businesses. Research data were collected during three participatory workshops for personnel from three different catering sector companies in Finland. Based on synthesized qualitative content analysis, eight elements influencing production and reduction of food waste were identified. Results revealed the diversity of managing food waste in the food service sector and how a holistic approach is required to prevent and reduce it. It is crucial to understand that food waste is manageable and should be an integral component of the management system. The model of eight factors provides a framework for recognition and management of food waste in the food service sector. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. An urban food store intervention positively affects food-related psychosocial variables and food behaviors.

    PubMed

    Gittelsohn, Joel; Song, Hee-Jung; Suratkar, Sonali; Kumar, Mohan B; Henry, Elizabeth G; Sharma, Sangita; Mattingly, Megan; Anliker, Jean A

    2010-06-01

    Obesity and other diet-related chronic diseases are more prevalent in low-income urban areas, which commonly have limited access to healthy foods. The authors implemented an intervention trial in nine food stores, including two supermarkets and seven corner stores, in a low-income, predominantly African American area of Baltimore City, with a comparison group of eight stores in another low-income area of the city. The intervention (Baltimore Healthy Stores; BHS) included an environmental component to increase stocks of more nutritious foods and provided point-of-purchase promotions including signage for healthy choices and interactive nutrition education sessions. Using pre- and postassessments, the authors evaluated the impact of the program on 84 respondents sampled from the intervention and comparison areas. Exposure to intervention materials was modest in the intervention area, and overall healthy food purchasing scores, food knowledge, and self-efficacy did not show significant improvements associated with intervention status. However, based on adjusted multivariate regression results, the BHS program had a positive impact on healthfulness of food preparation methods and showed a trend toward improved intentions to make healthy food choices. Respondents in the intervention areas were significantly more likely to report purchasing promoted foods because of the presence of a BHS shelf label. This is the first food store intervention trial in low-income urban communities to show positive impacts at the consumer level.

  2. 21 CFR 25.32 - Foods, food additives, and color additives.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... use in food, drugs, devices, or cosmetics. (d) Testing and certification of batches of a color... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Foods, food additives, and color additives. 25.32 Section 25.32 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL...

  3. 21 CFR 25.32 - Foods, food additives, and color additives.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... use in food, drugs, devices, or cosmetics. (d) Testing and certification of batches of a color... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Foods, food additives, and color additives. 25.32 Section 25.32 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL...

  4. 21 CFR 25.32 - Foods, food additives, and color additives.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... use in food, drugs, devices, or cosmetics. (d) Testing and certification of batches of a color... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Foods, food additives, and color additives. 25.32 Section 25.32 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL...

  5. 21 CFR 25.32 - Foods, food additives, and color additives.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... use in food, drugs, devices, or cosmetics. (d) Testing and certification of batches of a color... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Foods, food additives, and color additives. 25.32 Section 25.32 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL...

  6. 21 CFR 25.32 - Foods, food additives, and color additives.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... use in food, drugs, devices, or cosmetics. (d) Testing and certification of batches of a color... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Foods, food additives, and color additives. 25.32 Section 25.32 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL...

  7. Results with Complementary Food Using Local Food Ingredients.

    PubMed

    Ahmed, Tahmeed; Islam, Munirul; Choudhury, Nuzhat; Hossain, Iqbal; Huq, Sayeeda; Mahfuz, Mustafa; Sarker, Shafiqul Alam

    2017-01-01

    Appropriate complementary food is a must for optimum growth of infants and children. The food should be diverse and be given in sufficient quantities 2-4 times a day depending upon age. Poverty, food insecurity, and lack of awareness regarding the choice of nutritious food ingredients are deterrents to optimum complementary feeding. In Bangladesh, 77% of children do not receive appropriate complementary food and, hence, the high prevalence of childhood malnutrition. We developed ready-to-use complementary foods (RUCFs) using locally available food ingredients, rice/lentil and chickpea, which conform to standard specifications. These foods were found to be acceptable by children and their mothers compared to the Pushti packet, the cereal-based supplement used in the erstwhile National Nutrition Program of Bangladesh. In a cluster-randomized community-based trial in rural Bangladesh among more than 5,000 children, the efficacy of rice/lentil- and chickpea-based RUCFs was compared with another commonly used supplementary food called wheat-soy blend++ (WSB++) and a commercial product called Plumpy'doz. Deceleration in length for age was significantly lower (by 0.02-0.04/month) in the rice/lentil, Plumpy'doz, and chickpea groups compared to the control group at 18 months of age. Weight-for-length z-score decline was lower only in Plumpy'doz and chickpea groups. WSB++ was not different from the control group. In children who received chickpea RUCF or Plumpy'doz, the prevalence of stunting was 5-6% lower at 18 months. These foods can be used to prevent or treat malnutrition among children, particularly those from food-insecure households. © 2017 Nestec Ltd., Vevey/S. Karger AG, Basel.

  8. Food concerns and support for environmental food policies and purchasing.

    PubMed

    Worsley, Anthony; Wang, Wei C; Burton, Melissa

    2015-08-01

    Consumer support for pro environmental food policies and food purchasing are important for the adoption of successful environmental policies. This paper examines consumers' views of food policy options as their predisposition to purchase pro environmental foods along with their likely demographic, educational and cognitive antecedents including food and environmental concerns and universalism values (relating to care for others and the environment). An online survey to assess these constructs was conducted among 2204 Australian adults in November 2011. The findings showed strong levels of support for both environmental food policies (50%-78% support) and pro environmental food purchasing (51%-69% intending to purchase pro environmental foods). Confirmatory factor analysis and structural equation modelling showed that different cognitive mediators exist along pathways between demographics and the two outcome variables. Support for food policy was positively related to food and environment concerns (std. Beta = 0.25), universalism (0.41), perceived control (0.07), and regulatory issues (0.64 but negatively with food security issues (-0.37). Environment purchasing intentions were positively linked to food and nutrition concerns (0.13), food and environment concerns (0.24), food safety concerns (0.19), food and animal welfare concerns (0.16), universalism (0.25), female gender (0.05), education (0.04), and perceived influence over the food system (0.17). In addition, health study in years 11 and 12 was positively related to the beginning of both of these pathways (0.07 for each). The results are discussed in relation to the opportunities that communications based on the mediating variables offer for the promotion of environmental food policies and purchasing. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Evaluating Food Safety Knowledge and Practices of Food Processors and Sellers Working in Food Facilities in Hanoi, Vietnam.

    PubMed

    Tran, Bach Xuan; DO, Hoa Thi; Nguyen, Luong Thanh; Boggiano, Victoria; LE, Huong Thi; LE, Xuan Thanh Thi; Trinh, Ngoc Bao; DO, Khanh Nam; Nguyen, Cuong Tat; Nguyen, Thanh Trung; Dang, Anh Kim; Mai, Hue Thi; Nguyen, Long Hoang; Than, Selena; Latkin, Carl A

    2018-04-01

    Consumption of fast food and street food is increasingly common among Vietnamese, particularly in large cities. The high daily demand for these convenient food services, together with a poor management system, has raised concerns about food hygiene and safety (FHS). This study aimed to examine the FHS knowledge and practices of food processors and sellers in food facilities in Hanoi, Vietnam, and to identify their associated factors. A cross-sectional study was conducted with 1,760 food processors and sellers in restaurants, fast food stores, food stalls, and street vendors in Hanoi in 2015. We assessed each participant's FHS knowledge using a self-report questionnaire and their FHS practices using a checklist. Tobit regression was used to determine potential factors associated with FHS knowledge and practices, including demographics, training experience, and frequency of health examination. Overall, we observed a lack of FHS knowledge among respondents across three domains, including standard requirements for food facilities (18%), food processing procedures (29%), and food poisoning prevention (11%). Only 25.9 and 38.1% of participants used caps and masks, respectively, and 12.8% of food processors reported direct hand contact with food. After adjusting for socioeconomic characteristics, these factors significantly predicted increased FHS knowledge and practice scores: (i) working at restaurants and food stalls, (ii) having FHS training, (iii) having had a physical examination, and (iv) having taken a stool test within the last year. These findings highlight the need of continuous training to improve FHS knowledge and practices among food processors and food sellers. Moreover, regular monitoring of food facilities, combined with medical examination of their staff, should be performed to ensure food safety.

  10. Integrating environmental management into food safety and food packaging in Malaysia: review of the food regulation 1985

    NASA Astrophysics Data System (ADS)

    Nordin, N. H.; Hara, H.; Kaida, N.

    2017-05-01

    Food safety is an important issue that is related to public safety to prevent the toxicity threats of the food. Management through legal approach has been used in Malaysia as one of the predominant approaches to manage the environment. In this regard, the Food Regulation 1985 has been one of the mechanisms of environmental management through legal approach in controlling the safety of packaged food in food packaging industry in Malaysia. The present study aims to analyse and to explain the implementation of the Food Regulation 1985 in controlling the safety of packaged food in Malaysia and to integrate the concept of environmental management into the food safety issue. Qualitative analysis on the regulation document revealed that there are two main themes, general and specific, while their seven sub themes are included harmful packages, safety packages, reuse packages, polyvinyl chloride (PVC), alcoholic bottle, toys, money and others and iron powder. The implementation of the Food Regulation 1985 in controlling the safety of packaged food should not be regarded solely for regulation purposes but should be further developed for a broader sense of food safety from overcoming the food poisoning.

  11. PROP taster status and self-perceived food adventurousness influence food preferences.

    PubMed

    Ullrich, Natalia V; Touger-Decker, Riva; O'sullivan-Maillet, Julie; Tepper, Beverly J

    2004-04-01

    To determine the influence of 6-n-propylthiouracil (PROP) taster status and food adventurousness on liking of bitter, hot, and pungent foods. Self-reported survey of food likes/dislikes for 70 foods. Subjects were classified as tasters or nontasters of PROP using a standard screening procedure. By their response to a query regarding their perceived frequency of trying unfamiliar foods, subjects were characterized as being more or less adventurous. A convenience sample of 232 healthy adults, 18 to 55 years of age, was recruited from the local community. Statistical analyses Individual foods were grouped using Principal Component Analysis. Analysis of variance was used to assess differences in liking of food groups as a function of PROP status and food adventurousness. PROP tasters who were more food adventurous liked chili peppers and hot sauce, other pungent condiments, strong alcohol, and bitter fruits and vegetables more than tasters who were less food adventurous (P< or =.05-.001). Nontasters liked most foods, and food adventurousness had little influence on food liking for these individuals. Food adventurous PROP tasters liked a wide variety of strong-tasting foods, whereas tasters who were less food adventurous showed the classic dislike of bitter, hot, and pungent foods. Previous studies might have overestimated the influence of PROP taster status on rejection of strong-tasting foods by not distinguishing individuals by food adventurousness.

  12. Food consumption data needs for food and agricultural policy.

    PubMed

    Myers, L H

    1994-09-01

    Food and agricultural policy strives to provide stable, safe, nutritional, and affordable food supplies with policies on farm income, low-income food security, food safety (including nutritional risk), and nutrition education. For each policy area, comparisons are made between food consumption data needs and information currently collected with four human nutrition monitoring system components administered by the U.S. Department of Agriculture. Identified data gaps become the basis for recommendations for future data needs. Food consumption data are essential to management of programs. However, many food safety and nutritional well-being issues require specific food product consumption data for high risk groups. Sampling procedures are often too aggregate to meet these needs. Food consumed away-from-home is not well measured, yet this market segment now accounts for about half of all consumer food expenditures. Surveys should be designed to provide complementary and additive data. A premium should be placed on standardizing household description variables to enable "splicing" together data from different surveys. Survey continuity across time is essential. Data collection should be planned with funding limitations and respondent burden in mind so that a balance is achieved between survey objectives and the practical constraints of obtaining accurate data.

  13. Low GI Food with Barley in Space Foods

    NASA Astrophysics Data System (ADS)

    Katayama, Naomi; Sugimoto, Manabu; Hashimoto, Hirofumi; Kihara, Makoto; Yamashita, Masamichi; Space Agriculture Task Force

    The construction of the life-support system to perform space, moon base, Mars emigration is demanded. The space foods will play a very important role of life support on this occasion. Particularly, in environment of the microgravity, our metabolism becomes less than the face of the Earth. The management of the blood sugar level is very important. We need to eat the meal which will be rise in blood sugar level slowly. The barley which includes much water-soluble dietary fibers is helpful to make low GI space food. After eating 30% barley with unpolished rice, blood sugar level was rise slowly. The cooking process is very important to our body in thinking about digestion and absorption. Soft foods, long-heated foods and grind-foods are easy to digest. After eating these-foods, our blood sugar level will rise, easily. We introduce the space foods with 30% wheat that the blood sugar level is hard to rising.

  14. Dust Modeling with GEOS-Chem: Evidence for Acidic Uptake on Dust Surfaces during INTEX-B

    NASA Technical Reports Server (NTRS)

    Fairlie, T. Duncan

    2007-01-01

    We use measurements of aerosol ion composition and size made from the DC8 aircraft during the 2006 INTEX-B airborne campaign to identify mineral dust signatures, and look for evidence for interaction of dust with acidic components. Coating of dust with sulfate or nitrate favors the role of dust particles as cloud condensation nucleii, can promote further uptake of SO2 and N2O5, can impact NOx/HNO3 partitioning, and can shift sulfate or nitrate towards larger sizes, affecting atmospheric lifetimes for both aerosol and gas components. Mineral dust had a pervasive presence on flights made during the Northern Pacific deployment of the INTEX-B mission. We use scatter plots of ion mixing ratios with Na+ and Ca(2+) to distinguish sea salt and mineral components of the aerosol distribution, respectively. Positive correlations of non-sea-salt sulfate and nitrate with calcium indicate that the dusty air stream is associated with polluted air masses. Sulfate-ammonium scatter plots indicate sulfate to be primarily in the form of (NH4)2SO4. A positive correlation between Ca(2+) and NO-, but little evidence of NH4NO3, suggests that NO3- may be associated with mineral dust surfaces. 3-d model simulations conducted with the GEOS-Chem chemical transport model indicate that transpacific transport from East Asia was principally responsible for the dust observed from the aircraft over the Pacific. We compare the aerosol component relationships in the model with those observed. Uptake of sulfate and nitrate on the dust is not yet represented in the model.

  15. Sensitivity of WRF-Chem model to land surface schemes: Assessment in a severe dust outbreak episode in the Central Mediterranean (Apulia Region)

    NASA Astrophysics Data System (ADS)

    Rizza, Umberto; Miglietta, Mario Marcello; Mangia, Cristina; Ielpo, Pierina; Morichetti, Mauro; Iachini, Chiara; Virgili, Simone; Passerini, Giorgio

    2018-03-01

    The Weather Research and Forecasting model with online coupled chemistry (WRF-Chem) is applied to simulate a severe Saharan dust outbreak event that took place over Southern Italy in March 2016. Numerical experiments have been performed applying a physics-based dust emission model, with soil properties generated from three different Land Surface Models, namely Noah, RUC and Noah-MP. The model performance in reproducing the severe desert dust outbreak is analysed using an observational dataset of aerosol and desert dust features that includes optical properties from satellite and ground-based sun-photometers, and in-situ particulate matter mass concentration (PM) data. The results reveal that the combination of the dust emission model with the RUC Land Surface Model significantly over-predicts the emitted mineral dust; on the other side, the combination with Noah or Noah-MP Land Surface Model (LSM) gives better results, especially for the daily averaged PM10.

  16. Spectroscopic study of food and food toxins

    NASA Astrophysics Data System (ADS)

    King, Gavin; Walsh, James E.; Martin, Suzanne

    2003-03-01

    Fungal infection of food causes billions of dollars of lost revenue per annum as well as health problems, to animals and humans, if consumed in sufficient quantities. Modern food sorting techniques rely on colour or other physical characteristics to filter diseased or otherwise unsuitable foodstuffs from healthy foodstuffs. Their speeds are such that up to 40,000 objects per second can be moved at 4 metres per second, through 1 m wide chutes that offer a wide view for colour and shape sorting. Grain type foods such as coffee or peanuts are often vulnerable to toxic infection from invading fungi. If this happens, then their texture, taste and colour can change. Up to now, only visible wavelengths and colour identification have been used to bulk-sort food, but there has been little research in the ultra violet regions of the spectrum to help identify fungus or toxin infection. This research specifically concentrated on the ultra violet (UV) spectral characteristics of food in an attempt to identify possible spectral changes that occur when healthy food items like peanuts become infected with toxin-producing fungi. Ultimately, the goal is to design, build and construct an optical detection system that can use these 'spectral fingerprints' to more quickly and efficiently detect toxically infected food items.

  17. Food Waste in the Food-Energy-Water Nexus: Energy and Water Footprints of Wasted Food

    NASA Astrophysics Data System (ADS)

    Kibler, K. M.; Sarker, T.; Reinhart, D.

    2016-12-01

    The impact of wasted food to the food-energy-water (FEW) nexus is not well conceptualized or quantified, and is thus poorly understood. While improved understanding of water and energy requirements for food production may be applied to estimate costs associated with production of wasted food, the post-disposal costs of food waste to energy and water sectors are unknown. We apply both theoretical methods and direct observation of landfill leachate composition to quantify the net energy and water impact of food waste that is disposed in landfills. We characterize necessary energy inputs and biogas production to compute net impact to the energy sector. With respect to water, we quantify the volumes of water needed to attain permitted discharge concentrations of treated leachate, as well as the gray water footprint necessary for waste assimilation to the ambient regulatory standard. We find that approximately three times the energy produced as biogas (4.6E+8 kWh) is consumed in managing food waste and treating contamination from wasted food (1.3E+9 kWh). This energy requirement represents around 3% of the energy consumed in food production. The water requirement for leachate treatment and assimilation may exceed the amount of water needed to produce food. While not a consumptive use, the existence and replenishment of sufficient quantities of water in the environment for waste assimilation is an ecosystem service of the hydrosphere. This type of analysis may be applied to create water quality-based standards for necessary instream flows to perform the ecosystem service of waste assimilation. Clearer perception of wasted food as a source/sink for energy and water within the FEW nexus could be a powerful approach towards reducing the quantities of wasted food and more efficiently managing food that is wasted. For instance, comparative analysis of FEW impact across waste management strategies (e.g. landfilling, composting, anaerobic digestion) may assist local governments

  18. Food terrorism and food defense on the Web.

    PubMed

    Taylor, Mary Kay

    2008-01-01

    Global food supplies are at risk of both accidental and deliberate contamination. As past incidents have demonstrated, food terrorism may cause social, economic, and political disruption. The United States increased its efforts to protect its food after 9/11 by broadening the roles of existing agencies, including the U.S. Department of Agriculture and the Food and Drug Administration, and by making coordination of food defense the responsibility of the Department of Homeland Security. However, weaknesses in the system remain. This article presents background information and Web sites useful for consumers, industry representatives, students, researchers, policy makers, and the librarians that serve them.

  19. AmeriFlux US-SP3 Slashpine-Donaldson-mid-rot- 12yrs

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Martin, Tim

    2016-01-01

    This is the AmeriFlux version of the carbon flux data for the site US-SP3 Slashpine-Donaldson-mid-rot- 12yrs. Site Description - Slash pine planted end of 1989 early 1990. Gholz and Clark, 2002. Agric. Forest Meteo. 112, 87 - 102; Ckark et al., 2004. Ecological Applications, 14, 1154 - 1171.

  20. The effects of television advertisements for junk food versus nutritious food on children's food attitudes and preferences.

    PubMed

    Dixon, Helen G; Scully, Maree L; Wakefield, Melanie A; White, Victoria M; Crawford, David A

    2007-10-01

    Television (TV) food advertising has attracted criticism for its potential role in promoting unhealthy dietary practices among children. Content analyses indicate junk food advertising is prevalent on Australian children's TV; healthy eating is rarely promoted. This paper presents (a) a cross-sectional survey examining associations between children's regular TV viewing habits and their food-related attitudes and behaviour; and (b) an experiment assessing the impact of varying combinations of TV advertisements (ads) for unhealthy and healthy foods on children's dietary knowledge, attitudes and intentions. The experimental conditions simulated possible models for regulating food ads on children's TV. Participants were 919 grade five and six students from schools in Melbourne, Australia. The survey showed that heavier TV use and more frequent commercial TV viewing were independently associated with more positive attitudes toward junk food; heavier TV use was also independently associated with higher reported junk food consumption. The experiment found that ads for nutritious foods promote selected positive attitudes and beliefs concerning these foods. Findings are discussed in light of methodological issues in media effects research and their implications for policy and practice. It is concluded that changing the food advertising environment on children's TV to one where nutritious foods are promoted and junk foods are relatively unrepresented would help to normalize and reinforce healthy eating.

  1. Managing uncertainty about food risks - Consumer use of food labelling.

    PubMed

    Tonkin, Emma; Coveney, John; Meyer, Samantha B; Wilson, Annabelle M; Webb, Trevor

    2016-12-01

    General consumer knowledge of and engagement with the production of food has declined resulting in increasing consumer uncertainty about, and sensitivity to, food risks. Emphasis is therefore placed on providing information for consumers to reduce information asymmetry regarding food risks, particularly through food labelling. This study examines the role of food labelling in influencing consumer perceptions of food risks. In-depth, 1-h interviews were conducted with 24 Australian consumers. Participants were recruited based on an a priori defined food safety risk scale, and to achieve a diversity of demographic characteristics. The methodological approach used, adaptive theory, was chosen to enable a constant interweaving of theoretical understandings and empirical data throughout the study. Participants discussed perceiving both traditional (food spoilage/microbial contamination) and modern (social issues, pesticide and 'chemical' contamination) risks as present in the food system. Food labelling was a symbol of the food system having managed traditional risks, and a tool for consumers to personally manage perceived modern risks. However, labelling also raised awareness of modern risks not previously considered. The consumer framing of risk presented demonstrates the need for more meaningful consumer engagement in policy decision making to ensure risk communication and management meet public expectations. This research innovatively identifies food labelling as both a symbol of, and a tool for, the management of perceived risks for consumers. Therefore it is imperative that food system actors ensure the authenticity and trustworthiness of all aspects of food labelling, not only those related to food safety. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Reducing food allergy: is there promise for food applications?

    USDA-ARS?s Scientific Manuscript database

    The incidence of food allergy has been increasing in recent years. Food allergy can be deadly, and strict avoidance of foods containing allergenic proteins is the only effective way to prevent food-induced allergic reaction. This approach poses challenges, because allergens are not always accurately...

  3. Comment on "A model for phosphate glass topology considering the modifying ion sub-network" [J. Chem. Phys. 140, 154501 (2014)

    NASA Astrophysics Data System (ADS)

    Sidebottom, David L.

    2015-03-01

    In a recent paper, Hermansen, Mauro, and Yue [J. Chem. Phys. 140, 154501 (2014)] applied the temperature-dependent constraint theory to model both the glass transition temperature, Tg, and fragility, m, of a series of binary alkali phosphate glasses of the form (R2O)x (P2 O 5) 1 - x , where R represents an alkali species. Key to their success seems to be the retention of linear constraints between the alkali ion (R+) and the non-bridging oxygens near Tg, which allows the model to mimic a supposed minimum for both Tg(x) and m(x) located near x = 0.2. However, the authors have overlooked several recent studies that clearly show there is no minimum in m(x). We argue that the retention of the alkali ion constraints at these temperatures is unjustified and question whether the model calculations can be revised to meet the actual experimental data. We also discuss alternative interpretations for the fragility based on two-state thermodynamics that can accurately account for its compositional dependence.

  4. Food insecurity among Dutch food bank recipients: a cross-sectional study.

    PubMed

    Neter, Judith E; Dijkstra, S Coosje; Visser, Marjolein; Brouwer, Ingeborg A

    2014-05-16

    To determine the prevalence of (very) low food security among Dutch food bank recipients, and to identify potential demographic, lifestyle and nutrition-related factors associated with (very) low food security. 11 of 135 Dutch food banks were selected throughout the Netherlands. 251 Dutch food bank recipients participated in the study (93 men and 158 women). Inclusion criteria for participation were: (1) at least 18 years of age, (2) sufficiently fluent in Dutch to participate in oral and written interviews, (3) recipient of a Dutch food bank for at least 1 month and (4) collect own food parcel at the food bank. A single member per household was included. Level of food security. The prevalence of food insecurity was 72.9% (N=183), of which 40.4% (N=74) reported very low food security. Of the very low food secure participants, 56.8% (N=42) reported they were ever hungry but did not eat because they could not afford enough food in the previous 3 months. Adjusted multinomial logistic regression analyses showed that households without children were less likely to experience low food security (OR 0.39 (95% CI 0.18 to 0.88)) and men (OR 0.24 (95% CI 0.11 to 0.51)) were less likely to experience very low food security, while low-educated recipients (OR 5.05 (95% CI 1.37 to 18.61)) were more likely to experience very low food security. Furthermore, recipients with high satisfaction with overall food intake (OR 0.46 (95% CI 0.27 to 0.78)), high perceived healthiness of overall food intake (OR 0.34 (95% CI 0.19 to 0.62)) or high self-efficacy of eating healthy (OR 0.62 (95% CI 0.40 to 0.96)) were less likely to experience very low food security. Our study showed high prevalence rates of food insecurity among Dutch food bank recipients, and identified subgroups at increased risk of food insecurity. More research is urgently needed on the underlying determinants of food insecurity and the effectiveness of food assistance by food banks. Published by the BMJ Publishing

  5. Food insecurity among Dutch food bank recipients: a cross-sectional study

    PubMed Central

    Neter, Judith E; Dijkstra, S Coosje; Visser, Marjolein; Brouwer, Ingeborg A

    2014-01-01

    Objective To determine the prevalence of (very) low food security among Dutch food bank recipients, and to identify potential demographic, lifestyle and nutrition-related factors associated with (very) low food security. Setting 11 of 135 Dutch food banks were selected throughout the Netherlands. Participants 251 Dutch food bank recipients participated in the study (93 men and 158 women). Inclusion criteria for participation were: (1) at least 18 years of age, (2) sufficiently fluent in Dutch to participate in oral and written interviews, (3) recipient of a Dutch food bank for at least 1 month and (4) collect own food parcel at the food bank. A single member per household was included. Primary outcome Level of food security. Results The prevalence of food insecurity was 72.9% (N=183), of which 40.4% (N=74) reported very low food security. Of the very low food secure participants, 56.8% (N=42) reported they were ever hungry but did not eat because they could not afford enough food in the previous 3 months. Adjusted multinomial logistic regression analyses showed that households without children were less likely to experience low food security (OR 0.39 (95% CI 0.18 to 0.88)) and men (OR 0.24 (95% CI 0.11 to 0.51)) were less likely to experience very low food security, while low-educated recipients (OR 5.05 (95% CI 1.37 to 18.61)) were more likely to experience very low food security. Furthermore, recipients with high satisfaction with overall food intake (OR 0.46 (95% CI 0.27 to 0.78)), high perceived healthiness of overall food intake (OR 0.34 (95% CI 0.19 to 0.62)) or high self-efficacy of eating healthy (OR 0.62 (95% CI 0.40 to 0.96)) were less likely to experience very low food security. Conclusions Our study showed high prevalence rates of food insecurity among Dutch food bank recipients, and identified subgroups at increased risk of food insecurity. More research is urgently needed on the underlying determinants of food insecurity and the effectiveness of

  6. Food Allergy Sensitization and Presentation in Siblings of Food Allergic Children

    PubMed Central

    Gupta, Ruchi; Walkner, Maddy; Greenhawt, Matthew; Lau, Claudia; Caruso, Deanna; Wang, Xiaobin; Pongracic, Jacqueline A.; Smith, Bridget

    2016-01-01

    Background Many parents of food allergic children have concerns about the development of food allergies in their other children. Objective We sought to determine prevalence of food sensitization and clinical food allergy among siblings of food allergic children. Methods Two thousand eight hundred and thirty-four children were enrolled in the Chicago Family Cohort Food Allergy study. One thousand one hundred and twenty children (ages 0–21 years) with a food allergy (defined by a reported reaction history and evidence of food-specific IgE or skin prick test) and at least one biological sibling were included in this study. Results Among siblings of children with food allergy, 33.4% had no sensitization and no clinical symptoms to food. Fifty-three percent had a positive food serum-specific IgE or skin prick test, but no reported symptoms of food allergy. Only 13.6% of siblings were both sensitized and clinically reactive to the same food. Milk allergy was the most common allergy among siblings (5.9%), followed by egg allergy (4.4%) and peanut allergy (3.7%). Conclusions In a large cohort of food allergic families, only a small proportion of siblings were both sensitized and clinically reactive to a food. Sensitization without reactivity was common among siblings. Testing for food allergy in siblings without a history of clinical reactivity appears to be unjustified. Screening may lead to negative consequences related to potential misdiagnosis and unnecessary avoidance of a food. More data are needed to determine the absolute risk of food allergy development in siblings of food allergic children. PMID:27421900

  7. Food safety concerns of fast food consumers in urban Ghana.

    PubMed

    Omari, Rose; Frempong, Godfred

    2016-03-01

    In Ghana, out-of-home ready-to-eat foods including fast food generally have been associated with food safety problems. Notwithstanding, fast food production and consumption are increasing in Ghana and therefore this study sought to determine the food safety issues of importance to consumers and the extent to which they worry about them. First, through three focus group discussions on consumers' personal opinions about food safety issues, some emergent themes were obtained, which were used to construct an open-ended questionnaire administered face-to-face to 425 respondents systematically sampled from 20 fast food restaurants in Accra. Findings showed that most fast food consumers were concerned about food hazards such as pesticide residue in vegetables, excessive use of artificial flavour enhancers and colouring substances, bacterial contamination, migrated harmful substances from plastic packages, and general unhygienic conditions under which food is prepared and sold. Consumers also raised concerns about foodborne diseases such as cholera, typhoid, food poisoning, diarrhoea, bird flu and swine flu. The logistic regression model showed that being male increased the likelihood of worrying about general food safety issues and excessive use of flavour enhancers than in females while being youthful increased the likelihood of being worried about typhoid fever than in older consumers. These findings imply that consumers in urban Ghana are aware and concerned about current trends of food safety and foodborne disease challenges in the country. Therefore, efforts targeted at improving food safety and reducing incidences of foodborne diseases should not only focus on public awareness creation but should also design more comprehensive programmes to ensure the making of food safety rules and guidelines and enforcing compliance to facilitate availability and consumers' choice of safe foods. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Analytical tools for identification of non-intentionally added substances (NIAS) coming from polyurethane adhesives in multilayer packaging materials and their migration into food simulants.

    PubMed

    Félix, Juliana S; Isella, Francesca; Bosetti, Osvaldo; Nerín, Cristina

    2012-07-01

    Adhesives used in food packaging to glue different materials can provide several substances as potential migrants, and the identification of potential migrants and migration tests are required to assess safety in the use of adhesives. Solid-phase microextraction in headspace mode and gas chromatography coupled to mass spectrometry (HS-SPME-GC-MS) and ChemSpider and SciFinder databases were used as powerful tools to identify the potential migrants in the polyurethane (PU) adhesives and also in the individual plastic films (polyethylene terephthalate, polyamide, polypropylene, polyethylene, and polyethylene/ethyl vinyl alcohol). Migration tests were carried out by using Tenax(®) and isooctane as food simulants, and the migrants were analyzed by gas chromatography coupled to mass spectrometry. More than 63 volatile and semivolatile compounds considered as potential migrants were detected either in the adhesives or in the films. Migration tests showed two non-intentionally added substances (NIAS) coming from PU adhesives that migrated through the laminates into Tenax(®) and into isooctane. Identification of these NIAS was achieved through their mass spectra, and 1,6-dioxacyclododecane-7,12-dione and 1,4,7-trioxacyclotridecane-8,13-dione were confirmed. Caprolactam migrated into isooctane, and its origin was the external plastic film in the multilayer, demonstrating real diffusion through the multilayer structure. Comparison of the migration values between the simulants and conditions will be shown and discussed.

  9. Economic Factors Impacting Food Allergen Management: Perspectives from the Food Industry.

    PubMed

    Gupta, Ruchi S; Taylor, Steve L; Baumert, Joseph L; Kao, Lauren M; Schuster, Erik; Smith, Bridget M

    2017-10-01

    Food allergies affect up to 8% of children in the United States and may occasionally lead to severe life-threatening reactions. Because there is currently no cure for food allergies, strict avoidance of the allergen-containing foods is the only means of preventing an allergic reaction. Consumers rely on food manufacturers to reliably track and declare the presence of food allergens in products. Over the past 10 to 20 years, the food industry has increasingly adopted allergen control approaches in its processing facilities. However, the major industry costs related to food allergen management have not been fully described. The objective of this study was to characterize the factors that contribute to the economic impact of food allergen control practices on the food industry. A focus group (n = 100) was conducted with food industry professionals to identify key areas of cost for food allergen management. A survey based on the domains identified was then developed and disseminated to a convenience sample (n = 50) of quality control food industry specialists with knowledge of their company's food allergen management practices. Nearly all companies (92%) produced food products containing one or more of the top eight allergenic foods recognized by the U.S. Food and Drug Administration or sesame seeds. Cleaning procedures, employee training, and the potential for a recall due to allergen cross-contact were most frequently rated as the important factors in food allergen management. Recalls due to food allergen cross-contact, cleaning procedures, equipment and premises design, and employee training were ranked as the greatest allergen management expenses. Although 96% of companies had a food allergen control plan in place, nearly half (42%) had at least one food allergen-related recall within the past 5 years. The industry appears to endorse a willingness to unify precautionary allergen labeling to communicate a clear message more effectively to consumers.

  10. Impulsive reactions to food-cues predict subsequent food craving.

    PubMed

    Meule, Adrian; Lutz, Annika P C; Vögele, Claus; Kübler, Andrea

    2014-01-01

    Low inhibitory control has been associated with overeating and addictive behaviors. Inhibitory control can modulate cue-elicited craving in social or alcohol-dependent drinkers, and trait impulsivity may also play a role in food-cue reactivity. The current study investigated food-cue affected response inhibition and its relationship to food craving using a stop-signal task with pictures of food and neutral stimuli. Participants responded slower to food pictures as compared to neutral pictures. Reaction times in response to food pictures positively predicted scores on the Food Cravings Questionnaire - State (FCQ-S) after the task and particularly scores on its hunger subscale. Lower inhibitory performance in response to food pictures predicted higher FCQ-S scores and particularly those related to a desire for food and lack of control over consumption. Task performance was unrelated to current dieting or other measures of habitual eating behaviors. Results support models on interactive effects of top-down inhibitory control processes and bottom-up hedonic signals in the self-regulation of eating behavior, such that low inhibitory control specifically in response to appetitive stimuli is associated with increased craving, which may ultimately result in overeating. © 2013.

  11. Food Allergy Sensitization and Presentation in Siblings of Food Allergic Children.

    PubMed

    Gupta, Ruchi S; Walkner, Madeline M; Greenhawt, Matthew; Lau, Claudia H; Caruso, Deanna; Wang, Xiaobin; Pongracic, Jacqueline A; Smith, Bridget

    2016-01-01

    Many parents of food allergic children have concerns about the development of food allergies in their other children. We sought to determine prevalence of food sensitization and clinical food allergy among siblings of food allergic children. Two thousand eight hundred and thirty-four children were enrolled in the Chicago Family Cohort Food Allergy study. One thousand one hundred and twenty children (ages 0-21 years) with a food allergy (defined by a reported reaction history and evidence of food-specific IgE or skin prick test) and at least 1 biological sibling were included in this study. Among siblings of children with food allergy, 33.4% had no sensitization and no clinical symptoms to food. Fifty-three percent had a positive food serum-specific IgE or skin prick test, but no reported symptoms of food allergy. Only 13.6% of siblings were both sensitized and clinically reactive to the same food. Milk allergy was the most common allergy among siblings (5.9%), followed by egg allergy (4.4%) and peanut allergy (3.7%). In a large cohort of food allergic families, only a small proportion of siblings were both sensitized and clinically reactive to a food. Sensitization without reactivity was common among siblings. Testing for food allergy in siblings without a history of clinical reactivity appears to be unjustified. Screening may lead to negative consequences related to potential misdiagnosis and unnecessary avoidance of a food. More data are needed to determine the absolute risk of food allergy development in siblings of food allergic children. Copyright © 2016 American Academy of Allergy, Asthma & Immunology. All rights reserved.

  12. Factors affecting food handling Practices among food handlers of Dangila town food and drink establishments, North West Ethiopia

    PubMed Central

    2014-01-01

    Background Food borne diseases are major health problems in developed and developing countries including Ethiopia. The problem is more noticeable in developing countries due to prevailing poor food handling and sanitation practices, inadequate food safety laws, weak regulatory systems, lack of financial resources to invest on safer equipments, and lack of education for food handlers. Methods The objective of this study was to assess food handling practice and associated factors among food handlers working in food and drinking establishments of Dangila town, North West Ethiopia. Cross-sectional quantitative study design was conducted among 406 food handlers working in 105 food and drink establishments from July to August 2013 in Dangila town. Data were collected using face to face interview with pretested structured questionnaire and physical observation. Result The mean age of the respondents was 22.7 ± 4.2 years of which 62.8% of the food handlers were females. Two hundred thirteen (52.5%) of food handlers had good food handling practices. Marital status (AOR = 7.52, 95% CI, 1.45-38.97), monthly income (AOR = 0.395, 95% CI, 0.25-0.62), knowledge about food handling (AOR = 1.69, 95% CI, 1.05-2.73), existence of shower facility (AOR = 1.89, 95% CI, 1.12-3.21) and separate dressing room (AOR = 1.97, 95% CI, 1.11-3.49) were found to be significantly associated with good food handling Practices. Conclusion Above half of food handlers had good food handling practices. Marital status, monthly income, knowledge status, existence of shower facility, existence of separate dressing room and presence of insect and rodent were factors associated with food handling Practices. PMID:24908104

  13. The Ontario Food and Nutrition Strategy: identifying indicators of food access and food literacy for early monitoring of the food environment.

    PubMed

    Boucher, Beatrice A; Manafò, Elizabeth; Boddy, Meaghan R; Roblin, Lynn; Truscott, Rebecca

    2017-09-01

    To address challenges Canadians face within their food environments, a comprehensive, multistakeholder, intergovernmental approach to policy development is essential. Food environment indicators are needed to assess population status and change. The Ontario Food and Nutrition Strategy (OFNS) integrates the food, agriculture and nutrition sectors, and aims to improve the health of Ontarians through actions that promote healthy food systems and environments. This report describes the process of identifying indicators for 11 OFNS action areas in two strategic directions (SDs): Healthy Food Access, and Food Literacy and Skills. The OFNS Indicators Advisory Group used a five-step process to select indicators: (1) potential indicators from national and provincial data sources were identified; (2) indicators were organized by SD, action area and data type; (3) selection criteria were identified, pilot tested and finalized; (4) final criteria were applied to refine the indicator list; and (5) indicators were prioritized after reapplication of selection criteria. Sixty-nine potential indicators were initially identified; however, many were individual-level rather than system-level measures. After final application of the selection criteria, one individual-level indicator and six system-level indicators were prioritized in five action areas; for six of the action areas, no indicators were available. Data limitations suggest that available data may not measure important aspects of the food environment, highlighting the need for action and resources to improve system-level indicators and support monitoring of the food environment and health in Ontario and across Canada.

  14. Adolescents’ Food Choice and the Place of Plant-Based Foods

    PubMed Central

    Ensaff, Hannah; Coan, Susan; Sahota, Pinki; Braybrook, Debbie; Akter, Humaira; McLeod, Helen

    2015-01-01

    A diet dominated by plant foods, with limited amounts of refined processed foods and animal products conveys substantial health benefits. This study sought to explore adolescents’ attitudes and perceptions towards plant-based foods. Semi-structured focus group interviews were conducted with adolescents (age 14–15 years) (n = 29) attending an inner city school in Yorkshire, UK. Using a grounded theory methodology, data analysis provided four main categories and related concepts revolving around adolescents’ perspectives on plant-based foods: food choice parameters; perceived drivers and benefits of plant-based foods; environmental food cues; barriers to plant-based food choice. In the emergent grounded theory, a clear disconnect between plant-based foods and the parameters that adolescents use to make food choices, is highlighted. Further, key barriers to adolescents adopting a plant-based diet are differentiated and considered with respect to practice and policy. The analysis offers a framework to remodel and re-present plant-based foods. In this way, it is proposed that a closer connection is possible, with consequent shifts in adolescents’ dietary behaviour towards a more plant-based diet and associated health benefits. PMID:26066012

  15. Adolescents' Food Choice and the Place of Plant-Based Foods.

    PubMed

    Ensaff, Hannah; Coan, Susan; Sahota, Pinki; Braybrook, Debbie; Akter, Humaira; McLeod, Helen

    2015-06-09

    A diet dominated by plant foods, with limited amounts of refined processed foods and animal products conveys substantial health benefits. This study sought to explore adolescents' attitudes and perceptions towards plant-based foods. Semi-structured focus group interviews were conducted with adolescents (age 14-15 years) (n = 29) attending an inner city school in Yorkshire, UK. Using a grounded theory methodology, data analysis provided four main categories and related concepts revolving around adolescents' perspectives on plant-based foods: food choice parameters; perceived drivers and benefits of plant-based foods; environmental food cues; barriers to plant-based food choice. In the emergent grounded theory, a clear disconnect between plant-based foods and the parameters that adolescents use to make food choices, is highlighted. Further, key barriers to adolescents adopting a plant-based diet are differentiated and considered with respect to practice and policy. The analysis offers a framework to remodel and re-present plant-based foods. In this way, it is proposed that a closer connection is possible, with consequent shifts in adolescents' dietary behaviour towards a more plant-based diet and associated health benefits.

  16. Terminologie alimentaire (Food Terminology).

    ERIC Educational Resources Information Center

    Pelletier, Jean-Francois

    1980-01-01

    Translations and descriptions are given in French for a number of English food terms: convenience foods, fast foods, fast foods industry, fast foods restaurant, frozen foods, deep frozen foods, fast frozen foods, quick frozen foods, dry frozen foods. (MSE)

  17. Classification of igneous rocks analyzed by ChemCam at Gale crater, Mars

    DOE PAGES

    Cousin, Agnes; Sautter, Violaine; Payré, Valérie; ...

    2017-02-09

    Several recent studies have revealed that Mars is not a simple basalt-covered planet, but has a more complex geological history. In Gale crater on Mars, the Curiosity rover discovered 59 igneous rocks. This article focuses on their textures (acquired from the cameras such as MAHLI and MastCam) and their geochemical compositions that have been obtained using the ChemCam instrument. Light-toned crystals have been observed in most of the rocks. They correspond to feldspars ranging from andesines/oligoclases to anorthoclases and sanidines in the leucocratic vesiculated rocks. Darker crystals observed in all igneous rocks (except the leucocratic vesiculated ones) were analyzed bymore » LIBS and mainly identified as Fe-rich pigeonites and Fe-augites. Iron oxides have been observed in all groups whereas F-bearing minerals have been detected only in few of them. From their textural analysis and their whole-rock compositions, all these 59 igneous rocks have been classified in five different groups; from primitive rocks i.e. dark aphanitic basalts/basanites, trachybasalts, tephrites and fine/coarse-grained gabbros/norites to more evolved materials i.e. porphyritic trachyandesites, leucocratic trachytes and quartz-diorites. The basalts and gabbros are found all along the traverse of the rover, whereas the felsic rocks are located before the Kimberley formation, i.e. close to the Peace Vallis alluvial fan deposits. This suggests that these alkali rocks have been transported by fluvial activity and could come from the Northern rim of the crater, and may correspond to deeper strata buried under basaltic regolith (Sautter et al., 2015). Some of the basaltic igneous rocks are surprisingly enriched in iron, presenting low Mg# similar to the nakhlite parental melt that cannot be produced by direct melting of the Dreibus and Wanke (1986) martian primitive mantle. The basaltic rocks at Gale are thus different from Gusev basalts. They could originate from different mantle reservoirs

  18. Classification of igneous rocks analyzed by ChemCam at Gale crater, Mars

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cousin, Agnes; Sautter, Violaine; Payré, Valérie

    Several recent studies have revealed that Mars is not a simple basalt-covered planet, but has a more complex geological history. In Gale crater on Mars, the Curiosity rover discovered 59 igneous rocks. This article focuses on their textures (acquired from the cameras such as MAHLI and MastCam) and their geochemical compositions that have been obtained using the ChemCam instrument. Light-toned crystals have been observed in most of the rocks. They correspond to feldspars ranging from andesines/oligoclases to anorthoclases and sanidines in the leucocratic vesiculated rocks. Darker crystals observed in all igneous rocks (except the leucocratic vesiculated ones) were analyzed bymore » LIBS and mainly identified as Fe-rich pigeonites and Fe-augites. Iron oxides have been observed in all groups whereas F-bearing minerals have been detected only in few of them. From their textural analysis and their whole-rock compositions, all these 59 igneous rocks have been classified in five different groups; from primitive rocks i.e. dark aphanitic basalts/basanites, trachybasalts, tephrites and fine/coarse-grained gabbros/norites to more evolved materials i.e. porphyritic trachyandesites, leucocratic trachytes and quartz-diorites. The basalts and gabbros are found all along the traverse of the rover, whereas the felsic rocks are located before the Kimberley formation, i.e. close to the Peace Vallis alluvial fan deposits. This suggests that these alkali rocks have been transported by fluvial activity and could come from the Northern rim of the crater, and may correspond to deeper strata buried under basaltic regolith (Sautter et al., 2015). Some of the basaltic igneous rocks are surprisingly enriched in iron, presenting low Mg# similar to the nakhlite parental melt that cannot be produced by direct melting of the Dreibus and Wanke (1986) martian primitive mantle. The basaltic rocks at Gale are thus different from Gusev basalts. They could originate from different mantle reservoirs

  19. Neural correlates of the food/non-food visual distinction.

    PubMed

    Tsourides, Kleovoulos; Shariat, Shahriar; Nejati, Hossein; Gandhi, Tapan K; Cardinaux, Annie; Simons, Christopher T; Cheung, Ngai-Man; Pavlovic, Vladimir; Sinha, Pawan

    2016-03-01

    An evolutionarily ancient skill we possess is the ability to distinguish between food and non-food. Our goal here is to identify the neural correlates of visually driven 'edible-inedible' perceptual distinction. We also investigate correlates of the finer-grained likability assessment. Our stimuli depicted food or non-food items with sub-classes of appealing or unappealing exemplars. Using data-classification techniques drawn from machine-learning, as well as evoked-response analyses, we sought to determine whether these four classes of stimuli could be distinguished based on the patterns of brain activity they elicited. Subjects viewed 200 images while in a MEG scanner. Our analyses yielded two successes and a surprising failure. The food/non-food distinction had a robust neural counterpart and emerged as early as 85 ms post-stimulus onset. The likable/non-likable distinction too was evident in the neural signals when food and non-food stimuli were grouped together, or when only the non-food stimuli were included in the analyses. However, we were unable to identify any neural correlates of this distinction when limiting the analyses only to food stimuli. Taken together, these positive and negative results further our understanding of the substrates of a set of ecologically important judgments and have clinical implications for conditions like eating-disorders and anhedonia. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Understanding Food Labels

    MedlinePlus

    ... Healthy eating for girls Understanding food labels Understanding food labels There is lots of info on food ... need to avoid because of food allergies. Other food label terms top In addition to the Nutrition ...