Science.gov

Sample records for tabular ascii format

  1. File-Format Program For Transferable Output ASCII Data

    NASA Technical Reports Server (NTRS)

    Bingle, Bradford

    1988-01-01

    TOAD utilities machine-independent and require minimal central memory. Transferable Output ASCII Data (TOAD) file-format computer program facilitates transfer of data files from one computer installation to another. TOAD files preferred type and record length, easy to edit, read, and write on magnetic tape or transfer across communications networks. Applications programs write TOAD files directly and conform to all ANSI FORTRAN 77 standards.

  2. Transferable Output ASCII Data (TOAD) file format description

    NASA Technical Reports Server (NTRS)

    Bingel, Bradford; Hammond, Dana

    1987-01-01

    Described is a format for writing ASCII data on a file to facilitate its transfer from one computer system to another. The TOAD format conforms to all ANSI FORTRAN 77 standards. There are two advantages in using the TOAD format. First, TOAD files are of the preferred type and record length to make them easy to edit, read from and write on magnetic tape, or transfer across communications networks. Secondly, application programs, using the TOAD format to write computational results, are more portable and the answer files easier to postprocess. TOAD utility software is listed in an appendix.

  3. GeoCSV: tabular text formatting for geoscience data

    NASA Astrophysics Data System (ADS)

    Stults, M.; Arko, R. A.; Davis, E.; Ertz, D. J.; Turner, M.; Trabant, C. M.; Valentine, D. W., Jr.; Ahern, T. K.; Carbotte, S. M.; Gurnis, M.; Meertens, C.; Ramamurthy, M. K.; Zaslavsky, I.; McWhirter, J.

    2015-12-01

    The GeoCSV design was developed within the GeoWS project as a way to provide a baseline of compatibility between tabular text data sets from various sub-domains in geoscience. Funded through NSF's EarthCube initiative, the GeoWS project aims to develop common web service interfaces for data access across hydrology, geodesy, seismology, marine geophysics, atmospheric science and other areas. The GeoCSV format is an essential part of delivering data via simple web services for discovery and utilization by both humans and machines. As most geoscience disciplines have developed and use data formats specific for their needs, tabular text data can play a key role as a lowest common denominator useful for exchanging and integrating data across sub-domains. The design starts with a core definition compatible with best practices described by the W3C - CSV on the Web Working Group (CSVW). Compatibility with CSVW is intended to ensure the broadest usability of data expressed as GeoCSV. An optional, simple, but limited metadata description mechanism was added to allow inclusion of important metadata with comma separated data, while staying with the definition of a "dialect" by CSVW. The format is designed both for creating new datasets and to annotate data sets already in a tabular text format such that they are compliant with GeoCSV.

  4. ascii2gdocs

    SciTech Connect

    Nightingale, Trever

    2011-11-30

    Enables UNIX and Mac OS X command line users to put (individually or batch mode) local ascii files into Google Documents, where the ascii is converted to Google Document format using formatting the user can specify.

  5. Elements of a next generation time-series ASCII data file format for Earth Sciences

    NASA Astrophysics Data System (ADS)

    Webster, C. J.

    2015-12-01

    Data in ASCII comma separated value (CSV) format are recognized as the most simple, straightforward and readable type of data present in the geosciences. Many scientific workflows developed over the years rely on data using this simple format. However, there is a need for a lightweight ASCII header format standard that is easy to create and easy to work with. Current OGC grade XML standards are complex and difficult to implement for researchers with few resources. Ideally, such a format should provide the data in CSV for easy consumption by generic applications such as spreadsheets. The format should use an existing time standard. The header should be easily human readable as well as machine parsable. The metadata format should be extendable to allow vocabularies to be adopted as they are created by external standards bodies. The creation of such a format will increase the productivity of software engineers and scientists because fewer translators and checkers would be required. Data in ASCII comma separated value (CSV) format are recognized as the most simple, straightforward and readable type of data present in the geosciences. Many scientific workflows developed over the years rely on data using this simple format. However, there is a need for a lightweight ASCII header format standard that is easy to create and easy to work with. Current OGC grade XML standards are complex and difficult to implement for researchers with few resources. Ideally, such a format would provide the data in CSV for easy consumption by generic applications such as spreadsheets. The format would use existing time standard. The header would be easily human readable as well as machine parsable. The metadata format would be extendable to allow vocabularies to be adopted as they are created by external standards bodies. The creation of such a format would increase the productivity of software engineers and scientists because fewer translators would be required.

  6. A Doppler-limited rubidium atlas in ascii format, 9500-12 300 cm -1

    NASA Astrophysics Data System (ADS)

    Ross, Amanda J.; Bertrand, Victor; Harker, Heather; Crozet, Patrick

    2010-11-01

    We present a Doppler-limited transmission spectrum of the rubidium dimer, suitable for frequency calibration of near infrared (e.g. Ti:sapphire) excitation experiments in the region 9500-12 300 cm -1. It provides an abundant source of reference peaks that can be used in a graphic environment to calibrate short (<1 cm -1) scans of excitation spectrum. This is a sequel to an iodine atlas in ascii format [1] that we routinely use for the same purpose in the visible spectrum. The rubidium spectrum was recorded at an instrumental resolution of 0.018 cm -1. Absolute precision is expected to be ˜0.005 cm -1, and relative precision ˜0.003 cm -1. The Rb 2 A-X transmission spectrum is available in ascii format, as supplementary material.

  7. AstroAsciiData: ASCII table Python module

    NASA Astrophysics Data System (ADS)

    Kümmel, Martin; Haase, Jonas

    2013-11-01

    ASCII tables continue to be one of the most popular and widely used data exchange formats in astronomy. AstroAsciiData, written in Python, imports all reasonably well-formed ASCII tables. It retains formatting of data values, allows column-first access, supports SExtractor style headings, performs column sorting, and exports data to other formats, including FITS, Numpy/Numarray, and LaTeX table format. It also offers interchangeable comment character, column delimiter and null value.

  8. Transferable Output ASCII Data (TOAD) gateway: Version 1.0 user's guide

    NASA Technical Reports Server (NTRS)

    Bingel, Bradford D.

    1991-01-01

    The Transferable Output ASCII Data (TOAD) Gateway, release 1.0 is described. This is a software tool for converting tabular data from one format into another via the TOAD format. This initial release of the Gateway allows free data interchange among the following file formats: TOAD; Standard Interface File (SIF); Program to Optimize Simulated Trajectories (POST) input; Comma Separated Value (TSV); and a general free-form file format. As required, additional formats can be accommodated quickly and easily.

  9. A quantitative model of ground-water flow during formation of tabular sandstone uranium deposits

    USGS Publications Warehouse

    Sanford, R.F.

    1994-01-01

    Presents a quantitative simulation of regional groundwater flow during uranium deposition in the Westwater Canyon Member and Jackpile Sandstone Member of the Upper Jurassic Morrison Formation in the San Juan basin. Topographic slope, shoreline position, and density contrasts in the lake and pore fluids controlled the directions of flow and recharge-discharge areas. The most important results for uranium ore deposit formation are that regional groundwater discharged throughout the basin, regional discharge was concentrated along the shore line or playa margin, flow was dominantly gravity driven, and compaction dewatering was negligible. A strong association is found between the tabular sandstone uranium deposits and major inferred zones of mixed local and regional groundwater discharge. -from Author

  10. Can ASCII data files be standardized for Earth Science?

    NASA Astrophysics Data System (ADS)

    Evans, K. D.; Chen, G.; Wilson, A.; Law, E.; Olding, S. W.; Krotkov, N. A.; Conover, H.

    2015-12-01

    NASA's Earth Science Data Systems Working Groups (ESDSWG) was created over 10 years ago. The role of the ESDSWG is to make recommendations relevant to NASA's Earth science data systems from user experiences. Each group works independently focusing on a unique topic. Participation in ESDSWG groups comes from a variety of NASA-funded science and technology projects, such as MEaSUREs, NASA information technology experts, affiliated contractor, staff and other interested community members from academia and industry. Recommendations from the ESDSWG groups will enhance NASA's efforts to develop long term data products. Each year, the ESDSWG has a face-to-face meeting to discuss recommendations and future efforts. Last year's (2014) ASCII for Science Data Working Group (ASCII WG) completed its goals and made recommendations on a minimum set of information that is needed to make ASCII files at least human readable and usable for the foreseeable future. The 2014 ASCII WG created a table of ASCII files and their components as a means for understanding what kind of ASCII formats exist and what components they have in common. Using this table and adding information from other ASCII file formats, we will discuss the advantages and disadvantages of a standardized format. For instance, Space Geodesy scientists have been using the same RINEX/SINEX ASCII format for decades. Astronomers mostly archive their data in the FITS format. Yet Earth scientists seem to have a slew of ASCII formats, such as ICARTT, netCDF (an ASCII dump) and the IceBridge ASCII format. The 2015 Working Group is focusing on promoting extendibility and machine readability of ASCII data. Questions have been posed, including, Can we have a standardized ASCII file format? Can it be machine-readable and simultaneously human-readable? We will present a summary of the current used ASCII formats in terms of advantages and shortcomings, as well as potential improvements.

  11. Investigation of growth of AgX tabular crystals.

    PubMed

    Larichev, T A; Kagakin, E I

    1998-07-15

    The process of tabular crystal formation during physical ripening of fine AgX (X=Br,I) emulsions is investigated. The tabular crystal growth is realized simultaneously via two mechanisms: ionic and coalescent. The relative contribution of those mechanisms to the tabular crystal growth is determined by the conditions of the physical ripening. It is possible to control the size and shape uniformity of the final AgX tabular crystals by adjusting the relative contributions of these mechanisms.

  12. SEGY to ASCII: Conversion and Plotting Program

    USGS Publications Warehouse

    Goldman, Mark R.

    1999-01-01

    This report documents a computer program to convert standard 4 byte, IBM floating point SEGY files to ASCII xyz format. The program then optionally plots the seismic data using the GMT plotting package. The material for this publication is contained in a standard tar file (of99-126.tar) that is uncompressed and 726 K in size. It can be downloaded by any Unix machine. Move the tar file to the directory you wish to use it in, then type 'tar xvf of99-126.tar' The archive files (and diskette) contain a NOTE file, a README file, a version-history file, source code, a makefile for easy compilation, and an ASCII version of the documentation. The archive files (and diskette) also contain example test files, including a typical SEGY file along with the resulting ASCII xyz and postscript files. Requirements for compiling the source code into an executable are a C++ compiler. The program has been successfully compiled using Gnu's g++ version 2.8.1, and use of other compilers may require modifications to the existing source code. The g++ compiler is a free, high quality C++ compiler and may be downloaded from the ftp site: ftp://ftp.gnu.org/gnu Requirements for plotting the seismic data is the existence of the GMT plotting package. The GMT plotting package may be downloaded from the web site: http://www.soest.hawaii.edu/gmt/

  13. SAM II Data and Information (ASCII)

    Atmospheric Science Data Center

    2016-09-01

    SAM II (ASCII) Data and Information Data obtained from the Stratospheric Aerosol Measurement (SAM) II instrument, ... Guide Documents:  Project Guide Data Set Guide Readme Files:  Data Set (Text file) ...

  14. A new model for tabular-type uranium deposits

    USGS Publications Warehouse

    Sanford, R.F.

    1992-01-01

    Tabular-type uranium deposits occur as tabular, originally subhorizontal bodies entirely within reduced fluvial sandstones of Late Silurian age or younger. This paper proposes that belts of tabular-type uranium deposits formed in areas of mixed local and regional groundwater discharge shortly after deposition of the host sediments. The general characteristics of tabular-type uranium deposits indicate that their essential feature was the formation at a density-stratified ground-water interface in areas of local and regional ground-water discharge. Reconstruction of the paleohydrogeology is the key to understanding the formation of these deposits. Geologic ground-water controls that favor discharge, such as the pinch-out of major aquifers, are also favorable for uranium ore. The combination of topographic and geologic features that both cause discharge is most favorable for ore deposition. -from Author

  15. Organic matter diagenesis as the key to a unifying theory for the genesis of tabular uranium-vanadium deposits in the Morrison Formation, Colorado Plateau

    USGS Publications Warehouse

    Hansley, P.L.; Spirakis, C.S.

    1992-01-01

    Interstitial, epigenetic amorphous organic matter is intimately associated with uranium in the Grants uranium region and is considered essential to genetic models for these deposits. In contrast, uranium minerals are intimately associated with authigenic vanadium chlorite and vanadium oxides in amorphous organic matter-poor ores of the Slick Rock and Henry Mountains mining districts and therefore, in some genetic models amorphous organic matter is not considered crucial to the formation of these deposits. Differences in organic matter content can be explained by recognizing that amorphous organic matter-poor deposits have been subjected to more advanced stages of diagenesis than amorphous organic matter-rich deposits. Evidence that amorphous organic matter was involved in the genesis of organic matter-poor, as well as organic matter-rich, deposits is described. -from Authors

  16. SEGY to ASCII Conversion and Plotting Program 2.0

    USGS Publications Warehouse

    Goldman, Mark R.

    2005-01-01

    INTRODUCTION SEGY has long been a standard format for storing seismic data and header information. Almost every seismic processing package can read and write seismic data in SEGY format. In the data processing world, however, ASCII format is the 'universal' standard format. Very few general-purpose plotting or computation programs will accept data in SEGY format. The software presented in this report, referred to as SEGY to ASCII (SAC), converts seismic data written in SEGY format (Barry et al., 1975) to an ASCII data file, and then creates a postscript file of the seismic data using a general plotting package (GMT, Wessel and Smith, 1995). The resulting postscript file may be plotted by any standard postscript plotting program. There are two versions of SAC: one version for plotting a SEGY file that contains a single gather, such as a stacked CDP or migrated section, and a second version for plotting multiple gathers from a SEGY file containing more than one gather, such as a collection of shot gathers. Note that if a SEGY file has multiple gathers, then each gather must have the same number of traces per gather, and each trace must have the same sample interval and number of samples per trace. SAC will read several common standards of SEGY data, including SEGY files with sample values written in either IBM or IEEE floating-point format. In addition, utility programs are present to convert non-standard Seismic Unix (.sux) SEGY files and PASSCAL (.rsy) SEGY files to standard SEGY files. SAC allows complete user control over all plotting parameters including label size and font, tick mark intervals, trace scaling, and the inclusion of a title and descriptive text. SAC shell scripts create a postscript image of the seismic data in vector rather than bitmap format, using GMT's pswiggle command. Although this can produce a very large postscript file, the image quality is generally superior to that of a bitmap image, and commercial programs such as Adobe Illustrator

  17. Chapter 6. Tabular data and graphical images in support of the U.S. Geological Survey National Oil and Gas Assessment-East Texas basin and Louisiana-Mississippi salt basins provinces, Jurassic Smackover interior salt basins total petroleum system (504902), Travis Peak and Hosston formations.

    USGS Publications Warehouse

    ,

    2006-01-01

    This chapter describes data used in support of the process being applied by the U.S. Geological Survey (USGS) National Oil and Gas Assessment (NOGA) project. Digital tabular data used in this report and archival data that permit the user to perform further analyses are available elsewhere on the CD-ROM. Computers and software may import the data without transcription from the Portable Document Format files (.pdf files) of the text by the reader. Because of the number and variety of platforms and software available, graphical images are provided as .pdf files and tabular data are provided in a raw form as tab-delimited text files (.tab files).

  18. Transferable Output ASCII Data (TOAD) editor version 1.0 user's guide

    NASA Technical Reports Server (NTRS)

    Bingel, Bradford D.; Shea, Anne L.; Hofler, Alicia S.

    1991-01-01

    The Transferable Output ASCII Data (TOAD) editor is an interactive software tool for manipulating the contents of TOAD files. The TOAD editor is specifically designed to work with tabular data. Selected subsets of data may be displayed to the user's screen, sorted, exchanged, duplicated, removed, replaced, inserted, or transferred to and from external files. It also offers a number of useful features including on-line help, macros, a command history, an 'undo' option, variables, and a full compliment of mathematical functions and conversion factors. Written in ANSI FORTRAN 77 and completely self-contained, the TOAD editor is very portable and has already been installed on SUN, SGI/IRIS, and CONVEX hosts.

  19. Rosetta: Ensuring the Preservation and Usability of ASCII-based Data into the Future

    NASA Astrophysics Data System (ADS)

    Ramamurthy, M. K.; Arms, S. C.

    2015-12-01

    Field data obtained from dataloggers often take the form of comma separated value (CSV) ASCII text files. While ASCII based data formats have positive aspects, such as the ease of accessing the data from disk and the wide variety of tools available for data analysis, there are some drawbacks, especially when viewing the situation through the lens of data interoperability and stewardship. The Unidata data translation tool, Rosetta, is a web-based service that provides an easy, wizard-based interface for data collectors to transform their datalogger generated ASCII output into Climate and Forecast (CF) compliant netCDF files following the CF-1.6 discrete sampling geometries. These files are complete with metadata describing what data are contained in the file, the instruments used to collect the data, and other critical information that otherwise may be lost in one of many README files. The choice of the machine readable netCDF data format and data model, coupled with the CF conventions, ensures long-term preservation and interoperability, and that future users will have enough information to responsibly use the data. However, with the understanding that the observational community appreciates the ease of use of ASCII files, methods for transforming the netCDF back into a CSV or spreadsheet format are also built-in. One benefit of translating ASCII data into a machine readable format that follows open community-driven standards is that they are instantly able to take advantage of data services provided by the many open-source data server tools, such as the THREDDS Data Server (TDS). While Rosetta is currently a stand-alone service, this talk will also highlight efforts to couple Rosetta with the TDS, thus allowing self-publishing of thoroughly documented datasets by the data producers themselves.

  20. Progress Report on the ASCII for Science Data, Airborne and Geospatial Working Groups of the 2014 ESDSWG for MEaSUREs

    NASA Astrophysics Data System (ADS)

    Evans, K. D.; Krotkov, N. A.; Mattmann, C. A.; Boustani, M.; Law, E.; Conover, H.; Chen, G.; Olding, S. W.; Walter, J.

    2014-12-01

    The Earth Science Data Systems Working Groups (ESDSWG) were setup by NASA HQ 10 years ago. The role of the ESDSWG is to make recommendations relevant to NASA's Earth science data systems from users experiences. Each group works independently focussing on a unique topic. Participation in ESDSWG groups comes from a variety of NASA-funded science and technology projects, NASA information technology experts, affiliated contractor staff and other interested community members from academia and industry. Recommendations from the ESDSWG groups will enhance NASA's efforts to develop long term data products. The ASCII for Science Data Working Group (WG) will define a minimum set of information that should be included in ASCII file headers so that the users will be able to access the data using only the header information. After reviewing various use cases, such as field data and ASCII data exported from software tools, and reviewing ASCII data guidelines documentation, this WG will deliver guidelines for creating ASCII files that contain enough header information to allow the user to access the science data. The Airborne WG's goal is to improve airborne data access and use for NASA science. The first step is to evaluate the state of airborne data and make recommendations focusing on data delivery to the DAACs (data centers). The long term goal is to improve airborne data use for Earth Science research. Many data aircraft observations are reported in ASCII format. The ASCII and Airborne WGs seem like the same group, but the Airborne WG is concerned with maintaining and using airborne for science research, not just the data format. The Geospatial WG focus is on the interoperability issues of Geospatial Information System (GIS) and remotely sensed data, in particular, focusing on DAAC(s) data from NASA's Earth Science Enterprise. This WG will provide a set of tools (GIS libraries) to use with training and/or cookbooks through the use of Open Source technologies. A progress

  1. Revisiting Bertin Matrices: New Interactions for Crafting Tabular Visualizations.

    PubMed

    Perin, Charles; Dragicevic, Pierre; Fekete, Jean-Daniel

    2014-12-01

    We present Bertifier, a web app for rapidly creating tabular visualizations from spreadsheets. Bertifier draws from Jacques Bertin's matrix analysis method, whose goal was to "simplify without destroying" by encoding cell values visually and grouping similar rows and columns. Although there were several attempts to bring this method to computers, no implementation exists today that is both exhaustive and accessible to a large audience. Bertifier remains faithful to Bertin's method while leveraging the power of today's interactive computers. Tables are formatted and manipulated through crossets, a new interaction technique for rapidly applying operations on rows and columns. We also introduce visual reordering, a semi-interactive reordering approach that lets users apply and tune automatic reordering algorithms in a WYSIWYG manner. Sessions with eight users from different backgrounds suggest that Bertifier has the potential to bring Bertin's method to a wider audience of both technical and non-technical users, and empower them with data analysis and communication tools that were so far only accessible to a handful of specialists. PMID:26356922

  2. An Uncertainty Quantification System for Tabular Equations of State

    NASA Astrophysics Data System (ADS)

    Carpenter, John; Robinson, Allen; Debusschere, Bert; Mattsson, Ann; Drake, Richard; Rider, William

    2013-06-01

    Providing analysts with information regarding the accuracy of computational models is key for enabling predictive design and engineering. Uncertainty in material models can make significant contributions to the overall uncertainty in calculations. As a first step toward tackling this large problem, we present an uncertainty quantification system for tabular equations of state (EOS). First a posterior distribution of EOS model parameters is inferred using Bayes rule and a set of experimental and computational data. EOS tables are generated for parameter states sampled from the posterior distribution. A new unstructured triangular table format allows for capturing multi-phase model behavior. A principal component analysis then reduces this set of tables to a mean table and most significant perturbations. This final set of tables is provided to hydrocodes for performing simulations using standard non-intrusive uncertainty propagation methods. A multi-phase aluminum model is used to demonstrate the system. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  3. Interpretation of Magnetic Phase Anomalies over 2D Tabular Bodies

    NASA Astrophysics Data System (ADS)

    Subrahmanyam, M.

    2016-05-01

    In this study, phase angle (inverse tangent of the ratio of the horizontal to vertical gradients of magnetic anomalies) profile over two-dimensional tabular bodies has been subjected to detailed analysis for determining the source parameters. Distances between certain characteristic positions on this phase curve are related to the parameters of two-dimensional tabular magnetic sources. In this paper, I have derived the mathematical expressions for these relations. It has been demonstrated here that for locating the origin of the 2D tabular source, knowledge on the type of the model (contact, sheet, dyke, and fault) is not necessary. A procedure is evolved to determine the location, depth, width and magnetization angle of the 2D sources from the mathematical expressions. The method is tested on real field data. The effect of the overlapping bodies is also discussed with two synthetic examples. The interpretation technique is developed for contact, sheet, dike and inclined fault bodies.

  4. Tabular water properties interface for Hydra-TH :

    SciTech Connect

    Carpenter, John H.; Belcourt, Kenneth Noel

    2013-04-01

    Completion of the CASL L3 milestone THM.CFD.P6.03 provides a tabular material properties capability to the Hydra code. A tabular interpolation package used in Sandia codes was modified to support the needs of multi-phase solvers in Hydra. Use of the interface is described. The package was released to Hydra under a government use license. A dummy physics was created in Hydra to prototype use of the interpolation routines. Finally, a test using the dummy physics verifies the correct behavior of the interpolation for a test water table. 3

  5. Min-cut segmentation of cursive handwriting in tabular documents

    NASA Astrophysics Data System (ADS)

    Davis, Brian L.; Barrett, William A.; Swingle, Scott D.

    2015-01-01

    Handwritten tabular documents, such as census, birth, death and marriage records, contain a wealth of information vital to genealogical and related research. Much work has been done in segmenting freeform handwriting, however, segmentation of cursive handwriting in tabular documents is still an unsolved problem. Tabular documents present unique segmentation challenges caused by handwriting overlapping cell-boundaries and other words, both horizontally and vertically, as "ascenders" and "descenders" overlap into adjacent cells. This paper presents a method for segmenting handwriting in tabular documents using a min-cut/max-flow algorithm on a graph formed from a distance map and connected components of handwriting. Specifically, we focus on line, word and first letter segmentation. Additionally, we include the angles of strokes of the handwriting as a third dimension to our graph to enable the resulting segments to share pixels of overlapping letters. Word segmentation accuracy is 89.5% evaluating lines of the data set used in the ICDAR2013 Handwriting Segmentation Contest. Accuracy is 92.6% for a specific application of segmenting first and last names from noisy census records. Accuracy for segmenting lines of names from noisy census records is 80.7%. The 3D graph cutting shows promise in segmenting overlapping letters, although highly convoluted or overlapping handwriting remains an ongoing challenge.

  6. Network-Based Visual Analysis of Tabular Data

    ERIC Educational Resources Information Center

    Liu, Zhicheng

    2012-01-01

    Tabular data is pervasive in the form of spreadsheets and relational databases. Although tables often describe multivariate data without explicit network semantics, it may be advantageous to explore the data modeled as a graph or network for analysis. Even when a given table design conveys some static network semantics, analysts may want to look…

  7. MCNP/X TRANSPORT IN THE TABULAR REGIME

    SciTech Connect

    HUGHES, H. GRADY

    2007-01-08

    The authors review the transport capabilities of the MCNP and MCNPX Monte Carlo codes in the energy regimes in which tabular transport data are available. Giving special attention to neutron tables, they emphasize the measures taken to improve the treatment of a variety of difficult aspects of the transport problem, including unresolved resonances, thermal issues, and the availability of suitable cross sections sets. They also briefly touch on the current situation in regard to photon, electron, and proton transport tables.

  8. Characterization of crystal defects in mixed tabular silver halide grains by conventional transmission electron microscopy and X-ray diffractometry

    NASA Astrophysics Data System (ADS)

    Goessens, C.; Schryvers, D.; Van Landuyt, J.; Amelinckx, S.; Verbeeck, A.; De Keyzer, R.

    1991-04-01

    Tabular silver bromide grains with iodide uniformly mixed in the shell were investigated with conventional transmission electron microscopy. The shell region was found to contain a large number of stacking faults parallel with the {111¯} edges and in some cases edge dislocations with a Burgers vector of 1/2 >[11¯0] type. An atomic model for the formation of the stacking faults during the growth is presented.

  9. Room temperature synthesis of silver nanowires from tabular silver bromide crystals in the presence of gelatin

    SciTech Connect

    Liu Suwen; Wehmschulte, Rudolf J. . E-mail: rwehmsch@fit.edu; Lian Guoda; Burba, Christopher M.

    2006-03-15

    Long silver nanowires were synthesized at room temperature by a simple and fast process derived from the development of photographic films. A film consisting of an emulsion of tabular silver bromide grains in gelatin was treated with a photographic developer (4-(methylamino)phenol sulfate (metol), citric acid) in the presence of additional aqueous silver nitrate. The silver nanowires have lengths of more than 50 {mu}m, some even more than 100 {mu}m, and average diameters of about 80 nm. Approximately, 70% of the metallic silver formed in the reduction consists of silver nanowires. Selected area electron diffraction (SAED) results indicate that the silver nanowires grow along the [111] direction. It was found that the presence of gelatin, tabular silver bromide crystals and silver ions in solution are essential for the formation of the silver nanowires. The nanowires appear to originate from the edges of the silver bromide crystals. They were characterized by transmission electron microscopy (TEM), SAED, scanning electron microscopy (SEM), and powder X-ray diffraction (XRD)

  10. A General-Purpose ASCII Decoder for Control of Peripheral Devices for CAI Terminals.

    ERIC Educational Resources Information Center

    Rigney, Joseph W.; Williams, Louis A.

    The ASCII (American Standard Code for Information Interchange) decoder described here accepts inputs from an acoustic coupler, or Modem, in a remote time-sharing system. On receipt of a special command character the decoder recognizes, stores, and decodes the next two decimal digits. The output can be used to access any one of 100 items. For…

  11. CAP: A Computer Code for Generating Tabular Thermodynamic Functions from NASA Lewis Coefficients

    NASA Technical Reports Server (NTRS)

    Zehe, Michael J.; Gordon, Sanford; McBride, Bonnie J.

    2001-01-01

    For several decades the NASA Glenn Research Center has been providing a file of thermodynamic data for use in several computer programs. These data are in the form of least-squares coefficients that have been calculated from tabular thermodynamic data by means of the NASA Properties and Coefficients (PAC) program. The source thermodynamic data are obtained from the literature or from standard compilations. Most gas-phase thermodynamic functions are calculated by the authors from molecular constant data using ideal gas partition functions. The Coefficients and Properties (CAP) program described in this report permits the generation of tabulated thermodynamic functions from the NASA least-squares coefficients. CAP provides considerable flexibility in the output format, the number of temperatures to be tabulated, and the energy units of the calculated properties. This report provides a detailed description of input preparation, examples of input and output for several species, and a listing of all species in the current NASA Glenn thermodynamic data file.

  12. CAP: A Computer Code for Generating Tabular Thermodynamic Functions from NASA Lewis Coefficients. Revised

    NASA Technical Reports Server (NTRS)

    Zehe, Michael J.; Gordon, Sanford; McBride, Bonnie J.

    2002-01-01

    For several decades the NASA Glenn Research Center has been providing a file of thermodynamic data for use in several computer programs. These data are in the form of least-squares coefficients that have been calculated from tabular thermodynamic data by means of the NASA Properties and Coefficients (PAC) program. The source thermodynamic data are obtained from the literature or from standard compilations. Most gas-phase thermodynamic functions are calculated by the authors from molecular constant data using ideal gas partition functions. The Coefficients and Properties (CAP) program described in this report permits the generation of tabulated thermodynamic functions from the NASA least-squares coefficients. CAP provides considerable flexibility in the output format, the number of temperatures to be tabulated, and the energy units of the calculated properties. This report provides a detailed description of input preparation, examples of input and output for several species, and a listing of all species in the current NASA Glenn thermodynamic data file.

  13. Chapter 2: Tabular Data and Graphical Images in Support of the U.S. Geological Survey National Oil and Gas Assessment - The Wind River Basin Province

    USGS Publications Warehouse

    Klett, T.R.; Le, P.A.

    2007-01-01

    This chapter describes data used in support of the process being applied by the U.S. Geological Survey (USGS) National Oil and Gas Assessment (NOGA) project. Digital tabular data used in this report and archival data that permit the user to perform further analyses are available elsewhere on this CD-ROM. Computers and software may import the data without transcription from the Portable Document Format files (.pdf files) of the text by the reader. Graphical images are provided as .pdf files and tabular data are provided in a raw form as tab-delimited text files (.tab files) because of the number and variety of platforms and software available.

  14. Summer Decay Processes in a Large Tabular Iceberg

    NASA Astrophysics Data System (ADS)

    Wadhams, P.; Wagner, T. M.; Bates, R.

    2012-12-01

    Summer Decay Processes in a Large Tabular Iceberg Peter Wadhams (1), Till J W Wagner(1) and Richard Bates(2) (1) Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA, UK (2) Scottish Oceans Institute, School of Geography and Geosciences, University of St Andrews, St. Andrews, Scotland KY16 9AL We present observational results from an experiment carried out during July-August 2012 on a giant grounded tabular iceberg off Baffin Island. The iceberg studied was part of the Petermann Ice Island B1 (PIIB1) which calved off the Petermann Glacier in NW Greenland in 2010. Since 2011 it has been aground in 100 m of water on the Baffin Island shelf at 69 deg 06'N, 66 deg 06'W. As part of the project a set of high resolution GPS sensors and tiltmeters was placed on the ice island to record rigid body motion as well as flexural responses to wind, waves, current and tidal forces, while a Waverider buoy monitored incident waves and swell. On July 31, 2012 a major breakup event was recorded, with a piece of 25,000 sq m surface area calving off the iceberg. At the time of breakup, GPS sensors were collecting data both on the main berg as well as on the newly calved piece, while two of us (PW and TJWW) were standing on the broken-out portion which rose by 0.6 m to achieve a new isostatic equilibrium. Crucially, there was no significant swell at the time of breakup, which suggests a melt-driven decay process rather than wave-driven flexural break-up. The GPS sensors recorded two disturbances during the hour preceding the breakup, indicative of crack growth and propagation. Qualitative observation during the two weeks in which our research ship was moored to, or was close to, the ice island edge indicates that an important mechanism for summer ablation is successive collapses of the overburden from above an unsupported wave cut, which creates a submerged ram fringing the berg. A model of buoyancy stresses induced by

  15. Hepatotoxicity by Dietary Supplements: A Tabular Listing and Clinical Characteristics

    PubMed Central

    García-Cortés, Miren; Robles-Díaz, Mercedes; Ortega-Alonso, Aida; Medina-Caliz, Inmaculada; Andrade, Raul J.

    2016-01-01

    Dietary supplements (DS) are extensively consumed worldwide despite unproven efficacy. The true incidence of DS-induced liver injury (DSILI) is unknown but is probably under-diagnosed due to the general belief of safety of these products. Reported cases of herbals and DS-induced liver injury are increasing worldwide. The aim of this manuscript is to report a tabular listing with a description of DS associated with hepatotoxicity as well as review the phenotype and severity of DSILI. Natural remedies related to hepatotoxicity can be divided into herbal product-induced liver injury and DS-induced liver injury. In this article, we describe different DS associated with liver injury, some of them manufactured DS containing several ingredients (Herbalife™ products, Hydroxycut™, LipoKinetix™, UCP-1 and OxyELITE™) while others have a single ingredient (green tea extract, linoleic acid, usnic acid, 1,3-Dimethylamylamine, vitamin A, Garcinia cambogia and ma huang). Additional DS containing some of the aforementioned ingredients implicated in liver injury are also covered. We have also included illicit androgenic anabolic steroids for bodybuilding in this work, as they are frequently sold under the denomination of DS despite being conventional drugs. PMID:27070596

  16. Hepatotoxicity by Dietary Supplements: A Tabular Listing and Clinical Characteristics.

    PubMed

    García-Cortés, Miren; Robles-Díaz, Mercedes; Ortega-Alonso, Aida; Medina-Caliz, Inmaculada; Andrade, Raul J

    2016-04-09

    Dietary supplements (DS) are extensively consumed worldwide despite unproven efficacy. The true incidence of DS-induced liver injury (DSILI) is unknown but is probably under-diagnosed due to the general belief of safety of these products. Reported cases of herbals and DS-induced liver injury are increasing worldwide. The aim of this manuscript is to report a tabular listing with a description of DS associated with hepatotoxicity as well as review the phenotype and severity of DSILI. Natural remedies related to hepatotoxicity can be divided into herbal product-induced liver injury and DS-induced liver injury. In this article, we describe different DS associated with liver injury, some of them manufactured DS containing several ingredients (Herbalife™ products, Hydroxycut™, LipoKinetix™, UCP-1 and OxyELITE™) while others have a single ingredient (green tea extract, linoleic acid, usnic acid, 1,3-Dimethylamylamine, vitamin A, Garcinia cambogia and ma huang). Additional DS containing some of the aforementioned ingredients implicated in liver injury are also covered. We have also included illicit androgenic anabolic steroids for bodybuilding in this work, as they are frequently sold under the denomination of DS despite being conventional drugs.

  17. Automated Generation of Tabular Equations of State with Uncertainty Information

    NASA Astrophysics Data System (ADS)

    Carpenter, John H.; Robinson, Allen C.; Debusschere, Bert J.; Mattsson, Ann E.

    2015-06-01

    As computational science pushes toward higher fidelity prediction, understanding the uncertainty associated with closure models, such as the equation of state (EOS), has become a key focus. Traditional EOS development often involves a fair amount of art, where expert modelers may appear as magicians, providing what is felt to be the closest possible representation of the truth. Automation of the development process gives a means by which one may demystify the art of EOS, while simultaneously obtaining uncertainty information in a manner that is both quantifiable and reproducible. We describe our progress on the implementation of such a system to provide tabular EOS tables with uncertainty information to hydrocodes. Key challenges include encoding the artistic expert opinion into an algorithmic form and preserving the analytic models and uncertainty information in a manner that is both accurate and computationally efficient. Results are demonstrated on a multi-phase aluminum model. *Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  18. Hepatotoxicity by Dietary Supplements: A Tabular Listing and Clinical Characteristics.

    PubMed

    García-Cortés, Miren; Robles-Díaz, Mercedes; Ortega-Alonso, Aida; Medina-Caliz, Inmaculada; Andrade, Raul J

    2016-01-01

    Dietary supplements (DS) are extensively consumed worldwide despite unproven efficacy. The true incidence of DS-induced liver injury (DSILI) is unknown but is probably under-diagnosed due to the general belief of safety of these products. Reported cases of herbals and DS-induced liver injury are increasing worldwide. The aim of this manuscript is to report a tabular listing with a description of DS associated with hepatotoxicity as well as review the phenotype and severity of DSILI. Natural remedies related to hepatotoxicity can be divided into herbal product-induced liver injury and DS-induced liver injury. In this article, we describe different DS associated with liver injury, some of them manufactured DS containing several ingredients (Herbalife™ products, Hydroxycut™, LipoKinetix™, UCP-1 and OxyELITE™) while others have a single ingredient (green tea extract, linoleic acid, usnic acid, 1,3-Dimethylamylamine, vitamin A, Garcinia cambogia and ma huang). Additional DS containing some of the aforementioned ingredients implicated in liver injury are also covered. We have also included illicit androgenic anabolic steroids for bodybuilding in this work, as they are frequently sold under the denomination of DS despite being conventional drugs. PMID:27070596

  19. Geosites inventory of the northwestern Tabular Middle Atlas of Morocco

    NASA Astrophysics Data System (ADS)

    El Wartiti, Mohamed; Malaki, Amina; Zahraoui, Mohamed; El Ghannouchi, Abdelilah; di Gregorio, Felice

    2008-07-01

    Across the northwestern Tabular Middle Atlas of Morocco there are many examples of landscapes, rocks and fossils that provide key evidence of a particular moment or period in Earth history. Such Earth heritage sites are important for educating the general public in environmental matters. They also serve as tools for demonstrating sustainable development and for illustrating methods of site conservation as well as remembering that rocks, minerals, fossils, soils, landforms form an integral part of the natural world. The significance of certain sites for aesthetic or tourism reasons is obvious. There are numerous geosites, which could contribute to effective exploitation of geotourism, often in conjunction with ecotourism. The strategy employed to such sites involves close consultation with all communities in the vicinity of the respective geosite and is not only aimed at tourism and education, but also at sustainable improvement of the infrastructure of the people of this area. Geological heritage sites, properly managed, can generate employment and new economic activities, especially in regions in need of new or additional sources of income.

  20. Analyzing Tabular and State-Transition Requirements Specifications in PVS

    NASA Technical Reports Server (NTRS)

    Owre, Sam; Rushby, John; Shankar, Natarajan

    1997-01-01

    We describe PVS's capabilities for representing tabular specifications of the kind advocated by Parnas and others, and show how PVS's Type Correctness Conditions (TCCs) are used to ensure certain well-formedness properties. We then show how these and other capabilities of PVS can be used to represent the AND/OR tables of Leveson and the Decision Tables of Sherry, and we demonstrate how PVS's TCCs can expose and help isolate errors in the latter. We extend this approach to represent the mode transition tables of the Software Cost Reduction (SCR) method in an attractive manner. We show how PVS can check these tables for well-formedness, and how PVS's model checking capabilities can be used to verify invariants and reachability properties of SCR requirements specifications, and inclusion relations between the behaviors of different specifications. These examples demonstrate how several capabilities of the PVS language and verification system can be used in combination to provide customized support for specific methodologies for documenting and analyzing requirements. Because they use only the standard capabilities of PVS, users can adapt and extend these customizations to suit their own needs. Those developing dedicated tools for individual methodologies may find these constructions in PVS helpful for prototyping purposes, or as a useful adjunct to a dedicated tool when the capabilities of a full theorem prover are required. The examples also illustrate the power and utility of an integrated general-purpose system such as PVS. For example, there was no need to adapt or extend the PVS model checker to make it work with SCR specifications described using the PVS TABLE construct: the model checker is applicable to any transition relation, independently of the PVS language constructs used in its definition.

  1. RF model of the distribution system as a communication channel, phase 2. Volume 4: Sofware source program and illustrations ASCII database listings

    NASA Technical Reports Server (NTRS)

    Rustay, R. C.; Gajjar, J. T.; Rankin, R. W.; Wentz, R. C.; Wooding, R.

    1982-01-01

    Listings of source programs and some illustrative examples of various ASCII data base files are presented. The listings are grouped into the following categories: main programs, subroutine programs, illustrative ASCII data base files. Within each category files are listed alphabetically.

  2. Preliminary investigation of the elemental variation and diagenesis of a tabular uranium deposit, La Sal Mine, San Juan County, Utah

    USGS Publications Warehouse

    Brooks, Robert A.; Campbell, John A.

    1976-01-01

    Ore in the La Sal mine, San Juan County, Utah, occurs as a typical tabular-type uranium deposit of the-Colorado Plateau. Uranium-vanadium occurs in the Salt Wash Member of the Jurassic Morrison Formation. Chemical and petrographic analyses were used to determine elemental variation and diagenetic aspects across the orebody. Vanadium is concentrated in the dark clay matrix, which constitutes visible ore. Uranium content is greater above the vanadium zone. Calcium, carbonate carbon, and lead show greater than fifty-fold increase across the ore zone, whereas copper and organic carbon show only a several-fold increase. Large molybdenum concentrations are present in and above the tabular layer, and large selenium concentrations occur below the uranium zone within the richest vanadium zone. Iron is enriched in the vanadium horizon. Chromium is depleted from above the ore and strongly enriched below. Elements that vary directly with the vanadium content include magnesium, iron, selenium, zirconium, strontium, titanium, lead, boron, yttrium, and scandium. The diagenetic sequence is as follows: (1) formation of secondary quartz overgrowths as cement; (2) infilling and lining of remaining pores with amber opaline material; (3) formation of vanadium-rich clay matrix, which has replaced overgrowths as well as quartz grains; (4) replacement of overgrowths and detrital grains by calcite; (5) infilling of pores with barite and the introduction of pyrite and marcasite.

  3. Genesis of the tabular-type vanadium-uranium deposits of the Henry Basin, Utah

    USGS Publications Warehouse

    Northrop, H.R.; Goldhaber, M.B.

    1990-01-01

    Tabular-type vanadium-uranium deposits occur in fluvial sandstones of the Salt Wash Member of the Morrison Formation of Late Jurassic age The mineralized intervals and the weakly mineralized lateral extensions are bounded both above and below by zones rich in dolomite cement. Carbon isotope values of dolomite cements indicate that at least two sources of carbon existed. One source appears to be the same as that which formed the bedded carbonates in the evaporites in the Tidwell Member of the Morrison Formation stratigraphically below the mineralized interval. The second carbon source is typical of terrestrially deposited carbonates generally associated with meteoric water-dominated environments. Oxygen isotope values of these dolomites show the same trend of isotopically light values above the mineralized interval and isotopically heavier values in and below that interval; they indicate that two isotopically distinct fluids were involved in the mineralizing process. Some aspects of the origin of gangue and ore phases are explainable on the basis of processes which occurred solely within the saline fluid, but key aspects of ore genesis involved the interaction of the saline and meteoric waters. It is postulated that the solution interface migrated vertically within the stratigraphic section. -from Authors

  4. All-optical implementation of ASCII by use of nonlinear material for optical encoding of necessary symbols

    NASA Astrophysics Data System (ADS)

    Dhar, Shantanu K.; Mukhopadhyay, Sourangshu

    2005-06-01

    We propose a simple all-optical technique for digital encoding of ASCII. The method accommodates a digital encoding system by using the optical tree architecture and a nonlinear-material-based optical switching operation.

  5. The functional role of tabular structures for large reef fishes: avoiding predators or solar irradiance?

    NASA Astrophysics Data System (ADS)

    Kerry, J. T.; Bellwood, D. R.

    2015-06-01

    Large reef fishes may often be seen sheltering under tabular structures on coral reefs. There are two principle explanations for this behaviour: avoidance of predation or avoidance of solar irradiance. This study sought supporting evidence to distinguish between these two explanations by examining the usage of tabular structures on a shallow mid-shelf reef of the Great Barrier Reef at midday and sunset. If predation avoidance is most important, usage should increase towards sunset; conversely, if avoidance of solar radiation is most important, more fishes should use cover at midday. Underwater video observations revealed that tabular structures were extensively used by large reef fishes at midday, being characterised by numerous species, especially Lutjanidae and Haemulidae. In contrast, at sunset, tabular structures were used by significantly fewer large reef fishes, being characterised mostly by species of unicornfish ( Naso spp.). Resident times of fishes using tabular structures were also significantly longer at midday (28:06 ± 5:55 min) than at sunset (07:47 ± 2:19 min). The results suggest that the primary function of tabular structures for large reef fishes is the avoidance of solar irradiance. This suggestion is supported by the position of fishes when sheltering. The majority of large reef fishes were found to shelter under the lip of tabular structure, facing outwards. This behaviour is thought to allow protection from harmful downwelling UV-B irradiance while allowing the fish to retain photopic vision and survey more of the surrounding area. These findings help to explain the importance of tabular structures for large reef fishes on coral reefs, potentially providing a valuable energetic refuge from solar irradiance.

  6. Do tabular corals constitute keystone structures for fishes on coral reefs?

    NASA Astrophysics Data System (ADS)

    Kerry, J. T.; Bellwood, D. R.

    2015-03-01

    This study examined the changes in community composition of reef fishes by experimentally manipulating the availability of shelter provided by tabular structures on a mid-shelf reef on the Great Barrier Reef. At locations where access to tabular corals ( Acropora hyacinthus and Acropora cytherea) was excluded, a rapid and sustained reduction in the abundance of large reef fishes occurred. At locations where tabular structure was added, the abundance and diversity of large reef fishes increased and the abundance of small reef fishes tended to decrease, although over a longer time frame. Based on their response to changes in the availability of tabular structures, nine families of large reef fishes were separated into three categories; designated as obligate, facultative or non-structure users. This relationship may relate to the particular ecological demands of each family, including avoidance of predation and ultraviolet radiation, access to feeding areas and reef navigation. This study highlights the importance of tabular corals for large reef fishes in shallow reef environments and provides a possible mechanism for local changes in the abundance of reef fishes following loss of structural complexity on coral reefs. Keystone structures have a distinct structure and disproportionate effect on their ecosystem relative to their abundance, as such the result of this study suggests tabular corals may constitute keystone structures on shallow coral reefs.

  7. Log ASCII Standard (LAS) Files for Geophysical (Gamma Ray) Wireline Well Logs and Their Application to Geologic Cross Section C-C' Through the Central Appalachian Basin

    USGS Publications Warehouse

    Trippi, Michael H.; Crangle, Robert D.

    2009-01-01

    U.S. Geological Survey (USGS) regional geologic cross section C-C' (Ryder and others, 2008) displays key stratigraphic intervals in the central Appalachian basin. For this cross section, strata were correlated by using descriptions of well cuttings and gamma ray well log traces. This report summarizes the procedures used to convert gamma ray curves on paper well logs to the digital Log ASCII (American Standard Code for Information Interchange) Standard (LAS) format using the third-party software application Neuralog. The procedures could be used with other geophysical wireline logs also. The creation of digital LAS files from paper well logs by using Neuralog is very helpful, especially when dealing with older logs with limited or nonexistent digital data. The LAS files from the gamma ray logs of 11 wells used to construct cross section C-C' are included in this report. They may be downloaded from the index page as a single ZIP file.

  8. Chapter 3: Tabular Data and Graphical Images in Support of the U.S. Geological Survey National Oil and Gas Assessment - Western Gulf Province, Smackover-Austin-Eagle Ford Composite Total Petroleum System (504702)

    USGS Publications Warehouse

    Klett, T.R.; Le, P.A.

    2006-01-01

    This chapter describes data used in support of the process being applied by the U.S. Geological Survey (USGS) National Oil and Gas Assessment (NOGA) project. Digital tabular data used in this report and archival data that permit the user to perform further analyses are available elsewhere on this CD-ROM. Computers and software may import the data without transcription from the Portable Document Format files (.pdf files) of the text by the reader. Because of the number and variety of platforms and software available, graphical images are provided as .pdf files and tabular data are provided in a raw form as tab-delimited text files (.tab files).

  9. Agribusiness and Natural Resources Education in Michigan. Job Competencies Needed. A Tabular Supplement to the Final Report.

    ERIC Educational Resources Information Center

    Thuemmel, William L.; And Others

    This manual contains a tabular report of the competency identification of job task analysis component (Part Two) of the research project entitled "Agribusiness and Natural Resources Education in Michigan: Employment Demand, Competencies Required, and Recommended Delivery Systems." The data is a tabular supplement to Chapter III of the final…

  10. Automated recognition and extraction of tabular fields for the indexing of census records

    NASA Astrophysics Data System (ADS)

    Clawson, Robert; Bauer, Kevin; Chidester, Glen; Pohontsch, Milan; Kennard, Douglas; Ryu, Jongha; Barrett, William

    2013-01-01

    We describe a system for indexing of census records in tabular documents with the goal of recognizing the content of each cell, including both headers and handwritten entries. Each document is automatically rectified, registered and scaled to a known template following which lines and fields are detected and delimited as cells in a tabular form. Whole-word or whole-phrase recognition of noisy machine-printed text is performed using a glyph library, providing greatly increased efficiency and accuracy (approaching 100%), while avoiding the problems inherent with traditional OCR approaches. Constrained handwriting recognition results for a single author reach as high as 98% and 94.5% for the Gender field and Birthplace respectively. Multi-author accuracy (currently 82%) can be improved through an increased training set. Active integration of user feedback in the system will accelerate the indexing of records while providing a tightly coupled learning mechanism for system improvement.

  11. Evaluation of Cathode-Ray Tube protection for the electronic tabular display subsystem (ETABS) engineering model

    NASA Astrophysics Data System (ADS)

    Wilson, A. R.

    1981-09-01

    This report describes the safety evaluation of the 25-inch (diagonal) rectangular cathode-ray tube (CRT) that is used in the engineering model of the Electronic Tabular Display Subsystem (ETABS). An evaluation of ETABS will be performed at the Federal Aviation Administration (FAA) Technical Center for possible application in FAA Air Route Traffic Control Centers (ARTCC). The safety evaluation included standard industry pressure testing and special implosion testing on 12 CRT samples. Eleven of the twelve CRT samples satisfactorily met the safety requirements for both the pressure and implosion testing. One CRT cracked when subjected to 45 pounds per square inch (psi) of air pressure; however, the CRT did not implode. The 25-inch rectangular CRT will therefore provide a high degree of safety for use in each of the two tabular displays of the ETABS engineering model.

  12. Log ASCII Standard (LAS) Files for Geophysical Wireline Well Logs and Their Application to Geologic Cross Sections Through the Central Appalachian Basin

    USGS Publications Warehouse

    Crangle, Robert D.

    2007-01-01

    Introduction The U.S. Geological Survey (USGS) uses geophysical wireline well logs for a variety of purposes, including stratigraphic correlation (Hettinger, 2001, Ryder, 2002), petroleum reservoir analyses (Nelson and Bird, 2005), aquifer studies (Balch, 1988), and synthetic seismic profiles (Kulander and Ryder, 2005). Commonly, well logs are easier to visualize, manipulate, and interpret when available in a digital format. In recent geologic cross sections E-E' and D-D', constructed through the central Appalachian basin (Ryder, Swezey, and others, in press; Ryder, Crangle, and others, in press), gamma ray well log traces and lithologic logs were used to correlate key stratigraphic intervals (Fig. 1). The stratigraphy and structure of the cross sections are illustrated through the use of graphical software applications (e.g., Adobe Illustrator). The gamma ray traces were digitized in Neuralog (proprietary software) from paper well logs and converted to a Log ASCII Standard (LAS) format. Once converted, the LAS files were transformed to images through an LAS-reader application (e.g., GeoGraphix Prizm) and then overlain in positions adjacent to well locations, used for stratigraphic control, on each cross section. This report summarizes the procedures used to convert paper logs to a digital LAS format using a third-party software application, Neuralog. Included in this report are LAS files for sixteen wells used in geologic cross section E-E' (Table 1) and thirteen wells used in geologic cross section D-D' (Table 2).

  13. A portable ultrasonic phased array device for tabular joint weld inspection of offshore platform structures

    NASA Astrophysics Data System (ADS)

    Shan, Baohua; Li, Jingan; Duan, Zhongdong; Ou, Jinping; Shen, Wei

    2012-05-01

    To meet the inspection need for complex tabular joints weld of offshore platform structures, a portable ultrasonic phased array inspection device is developed. The integrated device is small and portable. As designed, the device can implement different algorithm of the ultrasonic phased array inspection technology. With proposed inspection plan, the experiment of Y tubular joint model was performed in lab. Experiment results indicate that the possible ultrasonic phased array inspection device can detect and visualize the flaws on Y tubular joint weld, which are nearly consistent with the actual condition.

  14. Sandia Unstructured Triangle Tabular Interpolation Package v 0.1 beta

    SciTech Connect

    2013-09-24

    The software interpolates tabular data, such as for equations of state, provided on an unstructured triangular grid. In particular, interpolation occurs in a two dimensional space by looking up the triangle in which the desired evaluation point resides and then performing a linear interpolation over the n-tuples associated with the nodes of the chosen triangle. The interface to the interpolation routines allows for automated conversion of units from those tabulated to the desired output units. when multiple tables are included in a data file, new tables may be generated by on-the-fly mixing of the provided tables

  15. Hydrogeology of an ancient arid closed basin: Implications for tabular sandstone-hosted uranium deposits

    SciTech Connect

    Sanford, R.F. )

    1990-11-01

    Hydrogeologic modeling shows that tabular-type uranium deposits in the grants uranium region of the San Juan basin, New Mexico, formed in zones of ascending and discharging regional ground-water flow. The association of either lacustrine mudstone or actively subsiding structures and uranium deposits can best be explained by the occurrence of lakes at topographic depressions where ground water having different sources and compositions is likely to converge, mix, and discharge. Ascending and discharging flow also explains the association of uranium deposits with underlying evaporites and suggests a brine interface. The simulations contradict previous suggestions that ground water moved downward in the mudflat.

  16. Hydrogeology of an ancient arid closed basin: implications for tabular sandstone-hosted uranium deposits

    USGS Publications Warehouse

    Sanford, R.F.

    1990-01-01

    Hydrogeologic modeling shows that tabular-type uranium deposits in the Grants uranium region of the San Juan basin, New Mexico, formed in zones of ascending and discharging regional ground-water flow. The association of either lacustrine mudstone or actively subsiding structures and uranium deposits can best be explained by the occurrence of lakes at topographic depressions where ground water having different sources and compositions is likely to converge, mix, and discharge. Ascending and discharging flow also explains the association of uranium deposits with underlying evaporites and suggests a brine interface. The simulations contradict previous suggestions that ground water moved downward in the mudflat. -Author

  17. Sandia Unstructured Triangle Tabular Interpolation Package v 0.1 beta

    2013-09-24

    The software interpolates tabular data, such as for equations of state, provided on an unstructured triangular grid. In particular, interpolation occurs in a two dimensional space by looking up the triangle in which the desired evaluation point resides and then performing a linear interpolation over the n-tuples associated with the nodes of the chosen triangle. The interface to the interpolation routines allows for automated conversion of units from those tabulated to the desired output units.more » when multiple tables are included in a data file, new tables may be generated by on-the-fly mixing of the provided tables« less

  18. The breakup of large tabular icebergs - direct observations and theoretical considerations

    NASA Astrophysics Data System (ADS)

    Wadhams, P.

    2013-12-01

    Peter Wadhams and Till Wagner Dept. of Applied Mathematics and Theoretical Physics (DAMTP), University of Cambridge. We review the factors governing the stability, dynamics and decay of icebergs and describe areas where current models are inadequate. These include questions such as draft changes in capsizing icebergs; iceberg trajectory modelling; the melt rate of the ice underside and ways of reducing it; and wave-induced flexure and its role in the break-up of tabular icebergs. In July 2012 the authors worked on a very large (42 sq km) tabular iceberg in Baffin Bay, which had calved from the Petermann Glacier in NW Greenland. We measured incoming swell spectrum and the iceberg response; also the role of buoyancy forces due to erosion of a waterline wave cut and the creation of an underwater ram. The iceberg broke up while we were on it, allowing an instrumental measurement of the calving event. The experiments were included in the BBC-2 film 'Operation Iceberg' shown on Nov 1 2012 and repeated on Nov 18. We conclude that two processes interacted in the break-up event: increased bending stress due to buoyancy of underwater rams; and direct flexural strain due to incidence of ocean swell. Implications for icebergs in the open sea are estimated.

  19. Tabular data and graphical images in support of the U.S. Geological Survey National Oil and Gas Assessment -- San Joaquin Basin (5010): Chapter 28 in Petroleum systems and geologic assessment of oil and gas in the San Joaquin Basin Province, California

    USGS Publications Warehouse

    Klett, T.R.; Le, P.A.

    2007-01-01

    This chapter describes data used in support of the assessment process. Digital tabular data used in this report and archival data that permit the user to perform further analyses are available elsewhere on this CD–ROM. Computers and software may import the data without transcription from the portable document format (.pdf) files of the text by the reader. Because of the number and variety of platforms and software available, graphical images are provided as .pdf files and tabular data are provided in a raw form as tab-delimited text files (.tab files).

  20. Tabular data and graphical images in support of the U.S. Geological Survey National Oil and Gas Assessment--San Juan Basin Province (5022): Chapter 7 in Total petroleum systems and geologic assessment of undiscovered oil and gas resources in the San Juan Basin Province, exclusive of Paleozoic rocks, New Mexico and Colorado

    USGS Publications Warehouse

    Klett, T.R.; Le, P.A.

    2013-01-01

    This chapter describes data used in support of the process being applied by the U.S. Geological Survey (USGS) National Oil and Gas Assessment (NOGA) project. Digital tabular data used in this report and archival data that permit the user to perform further analyses are available elsewhere on this CD–ROM. Computers and software may import the data without transcription from the Portable Document Format files (.pdf files) of the text by the reader. Because of the number and variety of platforms and software available, graphical images are provided as .pdf files and tabular data are provided in a raw form as tab-delimited text files (.tab files).

  1. Chapter 3. Tabular data and graphical images in support of the U.S. Geological Survey National Oil and Gas Assessment--East Texas basin and Louisiana-Mississippi salt basins provinces, Jurassic Smackover Interior salt basins total petroleum system (504902), Cotton Valley group.

    USGS Publications Warehouse

    Klett, T.R.; Le, P.A.

    2006-01-01

    This chapter describes data used in support of the process being applied by the U.S. Geological Survey (USGS) National Oil and Gas Assessment (NOGA) project. Digital tabular data used in this report and archival data that permit the user to perform further analyses are available elsewhere on the CD-ROM. Computers and software may import the data without transcription from the Portable Document Format files (.pdf files) of the text by the reader. Because of the number and variety of platforms and software available, graphical images are provided as .pdf files and tabular data are provided in a raw form as tab-delimited text files (.tab files).

  2. An EXCEL macro for importing log ASCII standard (LAS) files into EXCEL worksheets

    NASA Astrophysics Data System (ADS)

    Özkaya, Sait Ismail

    1996-02-01

    An EXCEL 5.0 macro is presented for converting a LAS text file into an EXCEL worksheet. Although EXCEL has commands for importing text files and parsing text lines, LAS files must be decoded line-by-line because three different delimiters are used to separate fields of differing length. The macro is intended to eliminate manual decoding of LAS version 2.0. LAS is a floppy disk format for storage and transfer of log data as text files. LAS was proposed by the Canadian Well Logging Society. The present EXCEL macro decodes different sections of a LAS file, separates, and places the fields into different columns of an EXCEL worksheet. To import a LAS file into EXCEL without errors, the file must not contain any unrecognized symbols, and the data section must be the last section. The program does not check for the presence of mandatory sections or fields as required by LAS rules. Once a file is incorporated into EXCEL, mandatory sections and fields may be inspected visually.

  3. Calcium-doped ceria/titanate tabular functional nanocomposite by layer-by-layer coating method

    SciTech Connect

    Liu, Xiang W.; Devaraju, M.K.; Yin, Shu; Sato, Tsugio

    2010-07-15

    Ca-doped ceria (CDC)/tabular titanate (K{sub 0.8}Li{sub 0.27}Ti{sub 1.73}O{sub 4}, TT) UV-shielding functional nanocomposite with fairly uniform CDC coating layers was prepared through a polyelectrolyte-associated layer-by-layer (LbL) coating method. TT with lepidocrocite-like layered structure was used as the substrate, poly (diallyldimethylammonium chloride) (PDDA) was used as a coupling agent, CDC nanoparticles were used as the main UV-shielding component. CDC/TT nanocomposites with various coating layers of CDC were obtained through a multistep coating process. The phases were studied by X-ray diffraction. The morphology and coating quality were studied by scanning electron microscopy and element mapping of energy dispersive X-ray analysis. The oxidation catalytic activity, UV-shielding ability and using comfort were characterized by Rancimat test, UV-vis spectra and dynamic friction test, respectively. CDC/TT nanocomposites with low oxidation catalytic activity, high UV-shielding ability and good using comfort were finally obtained. - Graphical abstract: Through the control of surface charge of particles calcium-doped ceria/titanate composites with low oxidation catalytic activity, higher UV-shielding ability and excellent comfort was obtained by a facile layer-by-layer coating method.

  4. Ambient seismic, hydroacoustic, and flexural gravity wave noise on a tabular iceberg

    NASA Astrophysics Data System (ADS)

    MacAyeal, Douglas R.; Wang, Yitan; Okal, Emile A.

    2015-02-01

    Cross correlation of ambient seismic noise between four seismographs on tabular iceberg C16, Ross Sea, Antarctica, reveals both the source and the propagation characteristics of signals associated with icebergs. We find that noise correlation functions computed from station data are asymmetric about zero time lag, and this indicates that noise observed on the iceberg originates primarily from a compact, localized source associated with iceberg collisions between C16 and a neighboring iceberg, B15A. We additionally find two, and possibly more, distinct phases of noise propagation. We believe that flexural gravity wave propagation dominates the low-frequency noise (>10 s period) and that hydroacoustic wave propagation in the water column between the ice and seabed appears to dominate high-frequency noise (>10 Hz). Faster seismic propagation dominates the intermediate band (2-6 Hz); however, we do not have sufficient data to characterize the wave mechanisms more precisely, e.g., by identifying distinct longitudinal and shear body waves and/or surface waves. Secular changes in the amplitude and timing of ambient noise correlations, e.g., a diurnal cycle and an apparent shift in the noise correlation of fast seismic modes between two periods of the deployment, allow us to speculate that ambient noise correlation analysis may be helpful in understanding the sources and environmental controls on iceberg-generated ocean noise as well as geometric properties (such as water column thickness) of subglacial lakes.

  5. TARFOX WALLOPS MET (ASCII)

    Atmospheric Science Data Center

    2014-04-25

    ... Ground Station Instrument:  Barometer Humidity Sensor Thermometer Wind Sensor Spatial Coverage:  ... ASDC Order Tool Parameters:  Pressure Relative Humidity Temperature Wind Direction Wind Speed Order ...

  6. Structural pattern of the Saïss basin and Tabular Middle Atlas in northern Morocco: Hydrological implications

    NASA Astrophysics Data System (ADS)

    Dauteuil, O.; Moreau, F.; Qarqori, K.

    2016-07-01

    The plain of Saïss is a fertile area of great agricultural production with major economic interests. Therefore, the improved knowledge about the water supply is imperative within a context of recurrent droughts and overexploitation of the groundwater. This plain is located in the Meknes-Fes basin and between two deformed domains: the Rif and Middle Atlas. The aquifers are fed by water coming from the Tabular Middle Atlas, for which the pathways are poorly constrained. This study provides new data to determine the water pathways based on a structural map produced from a novel analysis of SPOT images and a digital elevation model. This structural map reveals two fracture sets trending NE-SW and NW-SE. The first set is well known and corresponds to a main trend that controlled the tectonic and stratigraphic evolution of the study area. On the other hand, the NW-SE set was poorly described until now: it is both diffuse and widespread on the Tabular Middle Atlas. A comparison between the regional water flow trend, drainage pattern and structural map shows that the NW-SE fractures control the water flow from the Tabular Middle Atlas to the Saïss plain. A hydrological model is discussed where the water flow is confined onto Liassic carbonates and driven by NW-SE fractures. This study explains how a detailed structural mapping shows hydrology constraints.

  7. Barometric effects on tabular iceberg drift in the Ross Sea, Antarctica

    NASA Astrophysics Data System (ADS)

    Turnbull, Ian D.

    The Inverse Barometer Effect (IBE) was observed in the nineteenth century by Sir James Clark Ross (Ross, 1854a), as deviations in sea-surface elevation in response to deviations in atmospheric pressure. This effect embodies the inverse relationship between sea-surface height (relative to long-term mean sea level) and atmospheric surface pressure. This thesis addresses the hypothesis that icebergs in the Ross Sea region of Antarctica are influenced by the same forces that create the IBE. This hypothesis is motivated by studies of icebergs in the Ross Sea, where drift data suggest that icebergs are drawn into temporary holding zones, or "Iceberg Parking Lots" situated where the surface pressure tends to display persistent, annual average low pressure. A physical explanation for the IBE's influence on icebergs is that they are often able to travel up the sea-surface slope induced by the IBE below atmospheric lows against the gravitational pull because of the pressure gradient force of the atmosphere acting on the iceberg's freeboard (the part of the iceberg that is above the waterline). Here, I evaluate the validity of the hypothesized IBE-iceberg relationship using a combined approach of data analysis and modeling. I have examined atmospheric surface pressure and wind records taken directly from the surfaces of four Ross Sea icebergs---B15A, B15K, C16, and B15J, and I have also built, and experimented with, models that predict iceberg drift response to atmospheric surface pressure and surface winds, using observed pressures and winds from B15A and B15J as model forcing. I additionally performed various experiments on a large, idealized tabular iceberg's physical sensitivity to the IBE using a model that treats atmospheric pressure and winds in an idealized, theoretical manner. I discovered that the IBE is indeed a significant influence on iceberg drift in and around Lewis Bay, just to the north of Ross Island, which will further our understanding of these icebergs

  8. Operations Support of Phase 2 Integrated Demonstration In Situ Bioremediation. Volume 2, Final report: Data in tabular form, Disks 2,3,4

    SciTech Connect

    Hazen, T.C.

    1993-09-01

    This document consists solely of data acquired during phase 2 of the integrated demonstration project concerning in situ bioremediation performed at the Savannah River Site, Aiken, South Carolina. The data is presented in tabular form.

  9. 17 CFR 232.305 - Number of characters per line; tabular and columnar information.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... information. (a) The narrative portion of a document shall not exceed 80 characters per line, including blank spaces, and shall not be presented in multi-column newspaper format. Non-narrative information...

  10. 17 CFR 232.305 - Number of characters per line; tabular and columnar information.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... information. (a) The narrative portion of a document shall not exceed 80 characters per line, including blank spaces, and shall not be presented in multi-column newspaper format. Non-narrative information...

  11. 17 CFR 232.305 - Number of characters per line; tabular and columnar information.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... information. (a) The narrative portion of a document shall not exceed 80 characters per line, including blank spaces, and shall not be presented in multi-column newspaper format. Non-narrative information...

  12. 17 CFR 232.305 - Number of characters per line; tabular and columnar information.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... information. (a) The narrative portion of a document shall not exceed 80 characters per line, including blank spaces, and shall not be presented in multi-column newspaper format. Non-narrative information...

  13. 17 CFR 232.305 - Number of characters per line; tabular and columnar information.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... information. (a) The narrative portion of a document shall not exceed 80 characters per line, including blank spaces, and shall not be presented in multi-column newspaper format. Non-narrative information...

  14. Radon constrains the transit time of springs water at the border between tabular Middle Atlas and the Sais Basin (Morocco)

    NASA Astrophysics Data System (ADS)

    Mayer, Adriano; Rouai, Mohammed; Saracco, Ginette; Dekayir, Abdelilak; Miche, Héléne

    2010-05-01

    The tabular Middle Atlas (TMA) is an important fractured karstic reservoir in northern Morocco constituted by Liassic limestones and dolomites with a nearly sub-horizontal attitude, overlying basalts, shales and evaporates of Triassic age, as well as Paleozoic anchi-metamorphic schists. The zone is characterised by relative abundant rainfall (700 mm/y) and the absence of a surface watershed, which lead to an important groundwater reservoir hosted in the karstic (k-) aquifer. TMA is bordered to the North by extensive graben-like, normal, northward, fault-systems, which burden the Karstic formations under Plio-quaternary sediments at the Sais Basin border. At this limit, several important springs of high water-quality occur at the northernmost outcropping Lias limestone, which is overlaid in some areas by quaternary travertines. Two of these springs in particular, Bittit and Ribaa springs, provide almost drinking water for the town of Meknes (0.7 Million inhabitants), for local population and agriculture. These springs experienced a significant drop in water flow-rate in the last decades. Although the main origin of this water is certainly the k-aquifer, the drop in water-table raises several questions regarding the modality of water transport (influence of fractured and karstic systems in particular) and the possible participations of other groundwater reservoirs, which may deteriorate the high water-quality. A recent study has been carried out to shed some light on these questions, by using geochemical methods (K, Mg, Na, Ca, Fe, Mn, Ba, Sr, As, Sb, Hg, HCO3, SO4, NO3, Cl, Br, delta18-O, deltaD, Rn, EC, O2, pH, Eh, Temp). Constraints on the groundwater flow-path have been obtained by using a radon- hydrochemical- isotopic characterisation of spring waters. Here we report the results of the first geochemical sample collection (November 09). Several springs in the TMA yield Mg-Ca HCO3 rich water equilibrated with limestone and dolomite, having a very similar Rn

  15. Comparison of Neural Networks and Tabular Nearest Neighbor Encoding for Hyperspectral Signature Classification in Unresolved Object Detection

    NASA Astrophysics Data System (ADS)

    Schmalz, M.; Ritter, G.; Key, R.

    Accurate and computationally efficient spectral signature classification is a crucial step in the nonimaging detection and recognition of spaceborne objects. In classical hyperspectral recognition applications using linear mixing models, signature classification accuracy depends on accurate spectral endmember discrimination [1]. If the endmembers cannot be classified correctly, then the signatures cannot be classified correctly, and object recognition from hyperspectral data will be inaccurate. In practice, the number of endmembers accurately classified often depends linearly on the number of inputs. This can lead to potentially severe classification errors in the presence of noise or densely interleaved signatures. In this paper, we present an comparison of emerging technologies for nonimaging spectral signature classfication based on a highly accurate, efficient search engine called Tabular Nearest Neighbor Encoding (TNE) [3,4] and a neural network technology called Morphological Neural Networks (MNNs) [5]. Based on prior results, TNE can optimize its classifier performance to track input nonergodicities, as well as yield measures of confidence or caution for evaluation of classification results. Unlike neural networks, TNE does not have a hidden intermediate data structure (e.g., the neural net weight matrix). Instead, TNE generates and exploits a user-accessible data structure called the agreement map (AM), which can be manipulated by Boolean logic operations to effect accurate classifier refinement algorithms. The open architecture and programmability of TNE's agreement map processing allows a TNE programmer or user to determine classification accuracy, as well as characterize in detail the signatures for which TNE did not obtain classification matches, and why such mis-matches occurred. In this study, we will compare TNE and MNN based endmember classification, using performance metrics such as probability of correct classification (Pd) and rate of false

  16. From steep feeders to tabular plutons - Emplacement controls of syntectonic granitoid plutons in the Damara Belt, Namibia

    NASA Astrophysics Data System (ADS)

    Hall, Duncan; Kisters, Alexander

    2016-01-01

    Granitoid plutons in the deeply eroded south Central Zone of the Damara Belt in Namibia commonly show tabular geometries and pronounced stratigraphic controls on their emplacement. Subhorizontal, sheet-like pluton geometries record emplacement during regional subhorizontal shortening, but the intrusion of spatially and temporally closely-related granitoid plutons at different structural levels and in distinct structural settings suggests independent controls on their levels of emplacement. We describe and evaluate the controls on the loci of the dyke-to-sill transition that initiated the emplacement of three syntectonic (560-530 Ma) plutons in the basement-cover stratigraphy of the Erongo region. Intrusive relationships highlight the significance of (1) rigidity anisotropies associated with competent sedimentary packages or pre-existing subhorizontal granite sheets and (2) rheological anisotropies associated with the presence of thick ductile marble horizons. These mechanical anisotropies may lead to the initial deflection of steep feeder conduits as well as subsequent pluton assembly by the repeated underaccretion of later magma batches. The upward displacement of regional isotherms due to the heat advection associated with granite emplacement is likely to have a profound effect on the mechanical stratification of the upper crust and, consequently, on the level at which granitoid pluton emplacement is initiated. In this way, pluton emplacement at progressively shallower crustal depths may have resulted in the unusually high apparent geothermal gradients recorded in the upper crustal levels of the Damara Belt during its later evolution.

  17. Tabular comparisons of the Flynn Creek impact crater, United States, Steinheim impact crater, Germany and Snowball explosion crater, Canada

    NASA Technical Reports Server (NTRS)

    Roddy, D. J.

    1977-01-01

    A tabular outline of comparative data is presented for 340 basic dimensional, morphological, and structural parameters and related aspects for three craters of the flat-floored, central uplift type, two of which are natural terrestrial impact craters and one is a large-scale experimental explosion crater. The three craters are part of a general class, in terms of their morphology and structural deformation that is represented on each of the terrestrial planets including the moon. One of the considered craters, the Flynn Creek Crater, was formed by a hypervelocity impact event approximately 360 m.y. ago in what is now north central Tennessee. The impacting body appears to have been a carbonaceous chondrite or a cometary mass. The second crater, the Steinheim Crater, was formed by an impact event approximately 14.7 m.y. ago in what is now southwestern Germany. The Snowball Crater was formed by the detonation of a 500-ton TNT hemisphere on flat-lying, unconsolidated alluvium in Alberta, Canada.

  18. MULSIM/PC -- a personal-computer-based structural analysis program for mine design in deep tabular deposits

    SciTech Connect

    Donato, D.A. )

    1993-01-01

    This Information Circular presents the MULSIM/PC system of numerical modeling computer programs developed by the US Bureau of Mines. This system consists of four programs: PREMUL, the preprocessor or mesh generator; MULSIM/PC, the actual numerical modeling program (number cruncher); MUL3D, a three-dimensional postprocessor; and MUL2D, a two-dimensional postprocessor. These programs were specifically designed to operate an IBM-compatible (MS-DOS-based) personal computers for easy transfer of this technology to the mining industry and academia. MULSIM/PC uses a subvariation of the boundary-element method, namely, the displacement-discontinuity technique, for linear-elastic geomechanical analysis of mine plans in one or two parallel underground tabular deposits. Results calculated by this technique include stresses and displacements as they relate to changing mine geometries and materials. In addition to describing the MULSIM/PC program and its features, and providing a detailed example model, this report also documents the associated preprocessing and postprocessing programs that are part of the MULSIM/PC system. User's guides for all the programs are contained in the appendixes following the main report.

  19. TARFOX UWC131A (ASCII)

    Atmospheric Science Data Center

    2014-04-25

    ... Scattering Coeff Cloud Condensation Nuclei Droplet Concentration Size Effective Droplet Radius Liquid Water Content Ozone (O3) Mixing Ratio Particle Number Concentration Order Data:  ASDC Order Tool:  Order Data ...

  20. BOREAS TF-1 SSA-OA Soil Characteristics Data

    NASA Technical Reports Server (NTRS)

    Black, T. Andrew; Chen, Z; Nesic, Z.; Hall, Forrest G. (Editor); Papagno, Andrea (Editor)

    2000-01-01

    The BOREAS TF-1 team collected several data sets in support of its efforts to characterize and interpret soil information at the SSA-OA tower site in 1994 as part of BOREAS. Data sets collected include soil respiration, temperature, moisture, and gravimetric data. The data are stored in tabular ASCII format.

  1. A GIS wind resource map with tabular printout of monthly and annual wind speeds for 2,000 towns in Iowa

    SciTech Connect

    Brower, M.C.; Factor, T.

    1997-12-31

    The Iowa Wind Energy Institute, under a grant from the Iowa Energy Center, undertook in 1994 to map wind resources in Iowa. Fifty-meter met towers were erected at 13 locations across the state deemed promising for utility-scale wind farm development. Two years of summarized wind speed, direction, and temperature data were used to create wind resource maps incorporating effects of elevation, relative exposure, terrain roughness, and ground cover. Maps were produced predicting long-term mean monthly and annual wind speeds on a one-kilometer grid. The estimated absolute standard error in the predicted annual average wind speeds at unobstructed locations is 9 percent. The relative standard error between points on the annual map is estimated to be 3 percent. These maps and tabular data for 2,000 cities and towns in Iowa are now available on the Iowa Energy Center`s web site (http.//www.energy.iastate.edu).

  2. The motion of the earth-moon system in modern tabular ephemerides. II - Inertial motion, mean longitude of the sun, and general precession in longitude

    NASA Technical Reports Server (NTRS)

    Stumpff, P.; Lieske, J. H.

    1984-01-01

    Properties of astronomical time scales (ET and UT) are considered, with particular emphasis on correctly determining of-date longitude as the sum of inertial mean longitude of the sun relative to the mean equinox of a fixed epoch (1950.0), and the general precession in longitude accumulated since the epoch. The inertial mean longitude and motion (relative to the mean equinox) are derived from tabular ephemerides such as the Jet Propulsion Laboratories' DE 102 and DE 96, by comparisons with subroutines based on Newcomb's perturbation theory. An unresolved inconsistency of approximately 1 second per century among the mean inertial motion of DE 102, IAU precession speed (1976), and the classical Newcomb of-date mean motion is found. Interpretation difficulties arising from the use of different systems of Ephemeris Time are also discussed.

  3. DataUp 2.0: Improving On a Tool For Helping Researchers Archive, Manage, and Share Their Tabular Data

    NASA Astrophysics Data System (ADS)

    Strasser, C.; Borda, S.; Cruse, P.; Kunze, J.

    2013-12-01

    There are many barriers to data management and sharing among earth and environmental scientists; among the most significant are a lack of knowledge about best practices for data management, metadata standards, or appropriate data repositories for archiving and sharing data. Last year we developed an open source web application, DataUp, to help researchers overcome these barriers. DataUp helps scientists to (1) determine whether their file is CSV compatible, (2) generate metadata in a standard format, (3) retrieve an identifier to facilitate data citation, and (4) deposit their data into a repository. With funding from the NSF via a supplemental grant to the DataONE project, we are working to improve upon DataUp. Our main goal for DataUp 2.0 is to ensure organizations and repositories are able to adopt and adapt DataUp to meet their unique needs, including connecting to analytical tools, adding new metadata schema, and expanding the list of connected data repositories. DataUp is a collaborative project between the California Digital Library, DataONE, the San Diego Supercomputing Center, and Microsoft Research Connections.

  4. Directory interchange format manual, version 3.0

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The Directory Interchange Format (DIF) is a data structure used to exchange directory level information about data sets among information systems. The format consists of a number of fields that describe the attributes of a directory entry and text blocks that contain a descriptive summary of and references for the directory entry. All fields and the summary are preceded by labels identifying their contents. All values are ASCII character strings. The structure is intended to be flexible, allowing for future changes in the contents of directory entries.

  5. RPF: An Extensible, Cross-Platform, Binary File Format for Radiation Physics Data

    SciTech Connect

    Ham, C L

    2002-09-10

    Lawrence Livermore National Laboratory's Radiation Technology Group (RTG) uses a number of computer codes for simulation and analysis of radiation data. The number of incompatible data formats that these data presented themselves in have continued to multiply. In the 1980's a Common Data Format (CDF, see Appendix A) was devised for internal use by the RTG. This format represented a single gamma-ray spectrum as ASCII energy/count pairs preceded by an ASCII header. The ASCII representation of the data assured that it was compatible on any computing platform and this format is still in use. In the mid 1990's it became apparent that instrument systems of greater complexity would demand a file format of larger capacity to support systems then on the drawing board, including networks of sensors collecting time series of gamma-ray spectra. These systems were in the planning stage and defined data structures were not available. It became apparent that a new storage format for nuclear measurements data would be needed and it would have to be flexible and extensible to accommodate the requirements of systems of the future. As part of an LDRD, we began to investigate what others were doing, especially in the high-energy physics community, to deal with the large volumes of data being generated. Of particular interest was the very general Hierarchical Data Format (HDF), developed and maintained by the National Center for Supercomputing Applications (NCSA), that we ultimately used to develop the Radiation Physics Format (RPF). The HDF subroutine library provides users with the ability to customize a data file format based on standard calls to the HDF subroutine library. The RPF was developed and deployed on Sun and Hewlett-Packard workstations running their proprietary versions of UNIX.

  6. Message Formats, Numeracy, Risk Perceptions of Alcohol-Attributable Cancer, and Intentions for Binge Drinking Among College Students.

    PubMed

    Chen, Yixin; Yang, Z Janet

    2015-01-01

    We conducted an experiment to examine whether risk perceptions of alcohol-attributable cancer influence college students' binge-drinking intention and to explore how message formats (text, table, and graph) and numeracy influence risk perceptions of alcohol-attributable cancer. We found that a majority of participants (87%) perceive some risks of alcohol-attributable cancer. Risk messages in tabular and graphic formats are more effective in elevating risk perceptions, but there is no significant difference between these two formats. Numeracy and its interaction with message formats, however, do not predict risk perceptions. We recommend risk messages should be delivered using tabular or graphic formats to enhance risk perceptions. We also advocate the less-is-more principle in presenting risk information. PMID:26376688

  7. Portable file management system in FORTRAN. II. The input/output routine for free-format text.

    PubMed

    Okada, M; Okada, M

    1986-04-01

    A software tool for inputing and outputing patient data (1/O routine) has been developed. Since this I/O routine is programmed exclusively in FORTRAN77, it will make a powerful tool for constructing a portable database system. Basically the routine manipulates an ASCII-coded text string that consists of lines demarcated by the CR code (13) and is terminated by the null code (0). The editing commands are preceded by one of the following ASCII characters: @, !, ], [, *, and _, and all the strings with an initial character other than these are interpreted as data to be inserted into the text. Since the routine uses two FORTRAN tools already reported, i.e. the subroutines to manipulate key files and the subroutines to manage variable length records, character strings can be stored without any restrictions in format or in size, and can be retrieved either sequentially or in an indexed manner.

  8. The roles of organic matter in the formation of uranium deposits in sedimentary rocks

    USGS Publications Warehouse

    Spirakis, C.S.

    1996-01-01

    Because reduced uranium species have a much smaller solubility than oxidized uranium species and because of the strong association of organic matter (a powerful reductant) with many uranium ores, reduction has long been considered to be the precipitation mechanism for many types of uranium deposits. Organic matter may also be involved in the alterations in and around tabular uranium deposits, including dolomite precipitation, formation of silicified layers, iron-titanium oxide destruction, dissolution of quartz grains, and precipitation of clay minerals. The diagenetic processes that produced these alterations also consumed organic matter. Consequently, those tabular deposits that underwent the more advanced stages of diagenesis, including methanogenesis and organic acid generation, display the greatest range of alterations and contain the smallest amount of organic matter. Because of certain similarities between tabular uranium deposits and Precambrian unconformity-related deposits, some of the same processes might have been involved in the genesis of Precambrian unconformity-related deposits. Hydrologic studies place important constraints on genetic models of various types of uranium deposits. In roll-front deposits, oxidized waters carried uranium to reductants (organic matter and pyrite derived from sulfate reduction by organic matter). After these reductants were oxidized at any point in the host sandstone, uranium minerals were reoxidized and transported further down the flow path to react with additional reductants. In this manner, the uranium ore migrated through the sandstone at a rate slower than the mineralizing ground water. In the case of tabular uranium deposits, the recharge of surface water into the ground water during flooding of lakes carried soluble humic material to the water table or to an interface where humate precipitated in tabular layers. These humate layers then established the chemical conditions for mineralization and related

  9. Mesotidal barrier complex, Sundance Formation, north-central Wyoming

    SciTech Connect

    Uhlir, D.M.; Vondra, C.F.; Akers, A.; Elliott, T.

    1986-08-01

    The sandstones and coquinas of the upper 20 m of the Sundance Formation are a tidal inlet, back-barrier shoal, and sandy tidal-flat sequence deposited at the close of marine Jurassic sedimentation in north-central Wyoming. The lateral migration of these interbarrier tidal inlets along the regressive shoreline of the late Sundance sea caused the coquinas and sandstones of the uppermost Sundance Formation to be deposited as tabular, laterally extensive units. Earlier models, which attach an offshore environment of deposition to this sequence, fail to explain the tabular gross geometry of the unit and its conformable stratigraphic relationship with the overlying nonmarine sediments of the Morrison Formation. Within the sandstone of the uppermost Sundance Formation, tidal bundles, sigmoidal reactivation surfaces, herringbone cross-lamination, and abundant mud drapes present considerable evidence for tidal influence during the deposition of the unit. The neap-spring cyclicity of the tidal bundles implies they were developed in a diurnal tidal setting. A meso-paleotidal range along the Late Jurassic shoreline is estimated, based on calculations of sediment transport rates during the tidal bundle development.

  10. Jargonial-Obfuscation(J-O) DISambiguation Elimination via Siegel-Baez Cognition Category-Semantics(C-S) in Siegel FUZZYICS=CATEGORYICS (Son of TRIZ)/(F=C) Tabular List-Format Dichotomy Truth-Table Matrix Analytics

    NASA Astrophysics Data System (ADS)

    Siegel, Carl Ludwig; Siegel, Edward Carl-Ludwig

    2011-03-01

    NOT "philosophy" per se but raising serious salient Arnol'd [Huygens and Barrow, Newton and Hooke(96)] questions begged is Rota empiricism Husserl VS. Frege maths-objects Dichotomy controversy: Hill-Haddock[Husserl or Frege?(00)]as manifestly-demonstrated by Hintikka[B.U.]-Critchey[Derrida Deconstruction Ethics(78)] deconstruction; Altshuler TRIZ; Siegel F=C/C-S; Siegel-Baez(UCR) Cognition C-S = "Category-theory ``+'' Cognitive-Semantics[Wierzbica-Langacker-Lakoff-Nunez[Where Maths Comes From(00)]-Fauconnier-Turner[Blending(98)]-Coulson[Semantic-Leaps (00)

  11. TOLNet Data Format for Lidar Ozone Profile & Surface Observations

    NASA Astrophysics Data System (ADS)

    Chen, G.; Aknan, A. A.; Newchurch, M.; Leblanc, T.

    2015-12-01

    The Tropospheric Ozone Lidar Network (TOLNet) is an interagency initiative started by NASA, NOAA, and EPA in 2011. TOLNet currently has six Lidars and one ozonesonde station. TOLNet provides high-resolution spatio-temporal measurements of tropospheric (surface to tropopause) ozone and aerosol vertical profiles to address fundamental air-quality science questions. The TOLNet data format was developed by TOLNet members as a community standard for reporting ozone profile observations. The development of this new format was primarily based on the existing NDAAC (Network for the Detection of Atmospheric Composition Change) format and ICARTT (International Consortium for Atmospheric Research on Transport and Transformation) format. The main goal is to present the Lidar observations in self-describing and easy-to-use data files. The TOLNet format is an ASCII format containing a general file header, individual profile headers, and the profile data. The last two components repeat for all profiles recorded in the file. The TOLNet format is both human and machine readable as it adopts standard metadata entries and fixed variable names. In addition, software has been developed to check for format compliance. To be presented is a detailed description of the TOLNet format protocol and scanning software.

  12. Attributes for MRB_E2RF1 Catchments by Major River Basins in the Conterminous United States: Basin Characteristics, 2002 Geospatial_Data_Presentation_Form: tabular digital data

    USGS Publications Warehouse

    Wieczorek, Michael E.; LaMotte, Andrew E.

    2010-01-01

    This tabular data set represents basin characteristics for the year 2002 compiled for every MRB_E2RF1 catchment of selected Major River Basins (MRBs, Crawford and others, 2006). These characteristics are reach catchment shape index, stream density, sinuosity, mean elevation, mean slope and number of road-stream crossings. The source data sets are based on a modified version of the U.S. Environmental Protection Agency's (USEPA) RF1_2 and include enhancements to support national and regional-scale surface-water quality modeling (Nolan and others, 2002; Brakebill and others, 2011) and the U.S. Census Bureau's TIGER/Line Files (U.S. Census Bureau,2006). The MRB_E2RF1 catchments are based on a modified version of the U.S. Environmental Protection Agency's (USEPA) ERF1_2 and include enhancements to support national and regional-scale surface-water quality modeling (Nolan and others, 2002; Brakebill and others, 2011). Data were compiled for every MRB_E2RF1 catchment for the conterminous United States covering New England and Mid-Atlantic (MRB1), South Atlantic-Gulf and Tennessee (MRB2), the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy (MRB3), the Missouri (MRB4), the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf (MRB5), the Rio Grande, Colorado, and the Great basin (MRB6), the Pacific Northwest (MRB7) river basins, and California (MRB8).

  13. A Tabular Approach to Titration Calculations

    ERIC Educational Resources Information Center

    Lim, Kieran F.

    2012-01-01

    Titrations are common laboratory exercises in high school and university chemistry courses, because they are easy, relatively inexpensive, and they illustrate a number of fundamental chemical principles. While students have little difficulty with calculations involving a single titration step, there is a significant leap in conceptual difficulty…

  14. Tabular Equation of State for Gold

    NASA Astrophysics Data System (ADS)

    Boettger, Jonathan; Honnell, Kevin; Peterson, Jeffrey; Greeff, Carl; Crockett, Scott

    2011-06-01

    A new, SESAME-type equation of state (EOS) is described for gold, suitable for use in hydrodynamic calculations. The EOS is tabulated on a rectangular temperature-and-density grid, spanning densities from 0 - 29 g/cc, temperatures from 0 - 85,000 K, and extending up to pressures of 1000 GPa. It is constructed using the standard decomposition of the pressure into a static-lattice cold curve, a thermal nuclear contribution, and a thermal electronic contribution. The cold curve is derived from a combination of empirical data and density functional theory, the thermal nuclear contribution from the Johnson model, and the thermal electronic contribution using Thomas-Fermi-Dirac theory. Pressures, internal energies, and Helmholtz free energies are tabulated as functions of temperature and density. Predictions for the room-temperature isotherm, principal Hugoniot, thermal expansion, heat capacity, and vapor pressure are compared with experimental data and with the EOS currently available in the SESAME library (SESAME 2700).

  15. Tabular equation of state for gold

    NASA Astrophysics Data System (ADS)

    Boettger, Jonathan; Honnell, Kevin G.; Peterson, Jeffrey H.; Greeff, Carl; Crockett, Scott

    2012-03-01

    A new, SESAME-type equation of state (EOS) , suitable for use in hydrodynamic calculations, is described for gold. Pressures, internal energies, and Helmholtz free energies are tabulated on a rectangular temperature-and-density grid, spanning densities from 0 - 36 g/cc, temperatures from 0 - 800 eV, and extending up to pressures of 800 GPa. The EOS is constructed using the standard decomposition of the pressure into a static-lattice cold curve, a thermal nuclear contribution, and a thermal electronic contribution. The cold curve is derived from existing diamond-anvil-cell measurements, the thermal nuclear contribution from the Johnson model, and the thermal electronic contribution using Thomas-Fermi-Dirac theory. Predictions of the new EOS (SESAME 2705) for the cold curve, roomtemperature isotherm, principal Hugoniot, thermal expansion, heat capacity, melt line, and vapor pressure compare favorably with experimental data and are superior to the EOS currently available in the SESAME library (SESAME 2700).

  16. A revision of the genus Paracanthonchus (Cyatholaimidae, Nematoda) with a tabular key to species and a description of P. mamubiae sp. n. from the deep North-Western Pacific

    NASA Astrophysics Data System (ADS)

    Miljutina, Maria A.; Miljutin, Dmitry M.

    2015-01-01

    The species-rich genus of marine free-living nematodes, Paracanthonchus Mikoletzky 1924 (Nematoda: Cyatholaimidae), is revised. The genus numbers 72 valid species; twenty are indicated as species inquirenda because of poor descriptions and/or doubtful placement in the genus. Species of the genus were described from all oceans and latitudes. Of valid species, 64 ones (90%) were described from the tidal or upper subtidal zones, four species were recorded from the medium or lower shelf, and three species are abyssal. Thirty one species (43%) are known from Europe and the Northern Africa; 19 and 9 ones were described from South and North America (respectively); 8 ones were recorded from Asia; and 6 ones from the Australian region. The type species, Paracanthonchus caecus Mikoletzky 1924 has been recorded by a number of authors from various oceans around the World, yet many of these specimens have only roughly resembled the type description. Evidently, this species represents a complex of closely related species. Possibly, the same situation is in some other Paracanthonchus species, the repeated findings of which have no strong resemblance to type specimens. A tabular key to species is provided. A new abyssal species Paracanthonchus mamubiae from the Zenkevich Rise (North-Western Pacific, off North Japan, 5350 m depth) is described. The new species is characterized by: the tail, which is long with a thin, cylindrical terminal section; the absence of lateral differentiation of the cuticle; the presence of two groups of lateral pores (level of posterior part of pharynx and in cloacal region); one large dorsal tooth and two pairs of small subventral teeth combined with pharyngostomal cuticular ridges forming two denticles which may appear as a third pair of subventral teeth; 3-5 indistinct tubular preanal supplements; and a massive, proximally paired gubernaculum possessing broad flattened plates on each distal end. Each flattened gubernacular plate bears numerous (50

  17. Directory interchange format manual, version 4.0

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The Directory Interchange Format (DIF) is a data structure used to exchange directory-level information about data sets among information systems. In general the format consists of a number of fields that describe the attributes of a directory entry and text blocks that contain a descriptive summary of and references for the directory entry. All fields and the summary are preceded by labels identifying their contents. All values are ASCII character strings. The structure is intended to be flexible, allowing for future changes in the contents of directory entries. The manual is structured as follows: section 1 is a general description of what constitutes a directory entry; section 2 describes the content of the individual fields within the data structure, together with some examples. Also included in the six appendices is a description of the syntax used within the examples; samples of the directory interchange format applied to different data sets; the allowable discipline keywords; a current list of valid location keywords; a list of allowable parameter keywords; a list of acronyns and a glossary of terms used; and a description of the Standard Formatted Data Unit header, which may be added to the front of a DIF file to identify the file as a registered standard format.

  18. BOREAS TF-9 SSA-OBS Branch Level Flux Data

    NASA Technical Reports Server (NTRS)

    Rayment, Mark B.; Jarvis, Paul G.; Hall, Forrest G. (Editor); Huemmrich, Karl (Editor)

    2000-01-01

    The BOREAS TF-9 team collected data that describe carbon dioxide and water vapor fluxes from foliage at the BOREAS SSA-OBS site from 07-April through 23-November-1996. The data are available in tabular ASCII files.

  19. BOREAS RSS-8 BIOME-BGC Model Simulations at Tower Flux Sites in 1994

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G. (Editor); Nickeson, Jaime (Editor); Kimball, John

    2000-01-01

    BIOME-BGC is a general ecosystem process model designed to simulate biogeochemical and hydrologic processes across multiple scales (Running and Hunt, 1993). In this investigation, BIOME-BGC was used to estimate daily water and carbon budgets for the BOREAS tower flux sites for 1994. Carbon variables estimated by the model include gross primary production (i.e., net photosynthesis), maintenance and heterotrophic respiration, net primary production, and net ecosystem carbon exchange. Hydrologic variables estimated by the model include snowcover, evaporation, transpiration, evapotranspiration, soil moisture, and outflow. The information provided by the investigation includes input initialization and model output files for various sites in tabular ASCII format.

  20. Analysis of Shublik Formation rocks from Mt. Michelson quadrangle, Alaska

    USGS Publications Warehouse

    Detterman, Robert L.

    1970-01-01

    Analysis of 88 samples from the Shublik formation on Fire Creek, Mt. Michelson Quadrangle, Alaska, are presented in tabular form. The results include the determination of elements by semiquantitative spectrographic analysis, phosphate by X-ray fluorescence, carbon dioxide by acid decomposable carbonate, total carbon by induction furnace, carbonate carbon by conversion using the conversion factor of 0.2727 for amount of carbon in carbon dioxide, and organic carbon by difference. A seven- cycle semilogarithmic chart presents the data graphically and illustrates the range, mode, and mean for some of the elements. The chart shows, also, the approximate concentration of the same elements in rocks similar to the black shale and limestone of the Shublik Formation. Each sample represents 5 feet of section and is composed of rock chips taken at 1 - foot intervals. The samples are keyed into a stratigraphic column of the formation. Rocks of the Shublik Formation contain anomalously high concentrations of some of the elements. These same elements might be expected to be high in some of the petroleum from northern Alaska if the Shublik Formation is a source for this petroleum. Several of the stratigraphic intervals may represent, also, a low-grade phosphate deposit.

  1. Depositional environments of the Santa Margarita Formation in the Miocene Santa Maria basin, Huasna syncline

    SciTech Connect

    Phillips, R.L. )

    1991-02-01

    Preliminary investigation of the depositional environments of the middle sandstone member of the late middle Miocene Santa Margarita Formation in the Huasna syncline suggests a current-dominated shallow shelf environment. Progradation of coarse-grained clastic and bioclastic-rich sediment over siltstone documents the initial stage of deposition of this sand body. Overlying the basal intensely bioturbated bioclastic sediments are large-scale tabular cross-beds, up to 16 m thick, interbedded with tabular lag deposits of barnacles, oysters, and echinoids. The tabular fossil-rich beds, which form sequences up to 6 m thick between the large-scale cross-beds, represent either deposition of bottom set beds of the large-scale cross-beds or current swept lag deposits. Increasing energy conditions are recorded vertically by a decrease in the amount of bioturbation and by an increase in large-scale cross-bed sets and cosets. however, in the northern outcrop area subtidal channels are incised into the upper bioclastic sediments suggesting local shoaling conditions. Paleocurrent data record a unidirectional southwest-directed current trend normal to the basin axis and the East Huasna fault. The coarse clastic deposition terminates with deposition of siltstone as energy conditions decreased and water depth again increased. A current-swept shallow shelf containing extensive sandwaves comprises the major depositional environments. The paleocurrent data and large-scale cross-beds suggest that the shallow shelf extended to the east of the Huasna syncline and that the currents were most likely tidal in origin.

  2. Facies architecture and depositional environments of the Upper Cretaceous Kaiparowits Formation, southern Utah

    NASA Astrophysics Data System (ADS)

    Roberts, Eric M.

    2007-04-01

    The Kaiparowits Formation is an unusually thick package of Upper Cretaceous (late Campanian) strata exposed in Grand Staircase-Escalante National Monument of southern Utah, USA. The formation was deposited within the rapidly subsiding Cordilleran foreland basin as part of a thick clastic wedge derived from sources in the Sevier orogenic belt, thrust sheets in southeastern Nevada and southern California, and the Mogollon slope in southwestern Arizona. Channel systems in the Kaiparowits Formation shifted from northeastward to southeastward flow over time, and for a short period of time, sea level rise in the Western Interior Seaway resulted in tidally influenced rivers and/or estuarine systems. Thick floodbasin pond deposits, large suspended-load channels, and poorly developed, hydromorphic paleosols dominate the sedimentary record, and all are suggestive of a relatively wet, subhumid alluvial system. This is supported by extremely rapid sediment accumulation rates (41 cm/ka), and high diversity and abundance of aquatic vertebrate and invertebrate fossils. Facies and architectural analysis was performed on the Kaiparowits Formation, resulting in the identification of nine distinct facies associations: 1) intraformational conglomerate, 2) mollusc-shell conglomerate, 3) major tabular sandstone, 4) major lenticular sandstone, 5) minor tabular and lenticular sandstone, 6) finely laminated, calcareous siltstone, 7) inclined heterolithic sandstone and mudstone, 8) sandy mudstone, and 9) carbonaceous mudstone. These facies associations are interpreted as: 1) channel lags, 2) rare channel-hosted storm beds, 3) meandering channels, 4) anastomosing channels, 5) crevasse splays and crevasse channels, 6) lakes, 7) tidally influenced fluvial and/or estuarine channels, 8) mud-dominated floodplains, and 9) swamps and oxbow lakes. Based on this analysis, the formation is subdivided into three informal units, representative of gross changes in alluvial architecture, including facies

  3. Rectangular subsonic jet flow field measurements

    NASA Technical Reports Server (NTRS)

    Morrison, Gerald L.; Swan, David H.

    1989-01-01

    Flow field measurements are presented of 3 subsonic rectangular cold air jets. The 3 cases presented had aspect ratios of 1 x 2, 1 x 4 at a Mach number of 0.09 and an aspect ratio of 1 x 2 at a Mach number of 0.9. All measurements were made using a 3-D laser Doppler anemoneter system. The presented data includes the mean velocity vector, all Reynolds stress tensor components, turbulent kinetic energy and velocity correlation coefficients. The data is presented in tabular and graphical form. No analysis of the measured data or comparison to other published data is made. All tabular data are available in ASCII format on MS-DOS compatible disks.

  4. Comet formation

    NASA Astrophysics Data System (ADS)

    Blum, J.

    2014-07-01

    There has been vast progress in our understanding of planetesimal formation over the past decades, owing to a number of laboratory experiments as well as to refined models of dust and ice agglomeration in protoplanetary disks. Coagulation rapidly forms cm-sized ''pebbles'' by direct sticking in collisions at low velocities (Güttler et al. 2010; Zsom et al. 2010). For the further growth, two model approaches are currently being discussed: (1) Local concentration of pebbles in nebular instabilities until gravitational instability occurs (Johansen et al. 2007). (2) A competition between fragmentation and mass transfer in collisions among the dusty bodies, in which a few ''lucky winners'' make it to planetesimal sizes (Windmark et al. 2012a,b; Garaud et al. 2013). Predictions of the physical properties of the resulting bodies in both models allow a distinction of the two formation scenarios of planetesimals. In particular, the tensile strength (i.e, the inner cohesion) of the planetesimals differ widely between the two models (Skorov & Blum 2012; Blum et al. 2014). While model (1) predicts tensile strengths on the order of ˜ 1 Pa, model (2) results in rather compactified dusty bodies with tensile strengths in the kPa regime. If comets are km-sized survivors of the planetesimal-formation era, they should in principle hold the secret of their formation process. Water ice is the prime volatile responsible for the activity of comets. Thermophysical models of the heat and mass transport close to the comet-nucleus surface predict water-ice sublimation temperatures that relate to maximum sublimation pressures well below the kPa regime predicted for formation scenario (2). Model (1), however, is in agreement with the observed dust and gas activity of comets. Thus, a formation scenario for cometesimals involving gravitational instability is favored (Blum et al. 2014).

  5. NASA Standard for Airborne Data: ICARTT Format ESDS-RFC-019

    NASA Astrophysics Data System (ADS)

    Thornhill, A.; Brown, C.; Aknan, A.; Crawford, J. H.; Chen, G.; Williams, E. J.

    2011-12-01

    Airborne field studies generate a plethora of data products in the effort to study atmospheric composition and processes. Data file formats for airborne field campaigns are designed to present data in an understandable and organized way to support collaboration and to document relevant and important meta data. The ICARTT file format was created to facilitate data management during the International Consortium for Atmospheric Research on Transport and Transformation (ICARTT) campaign in 2004 that involved government-agencies and university participants from five countries. Since this mission the ICARTT format has been used in subsequent field campaigns such as Polar Study Using Aircraft Remote Sensing, Surface Measurements and Models of Climates, Chemistry, Aerosols, and Transport (POLARCAT) and the first phase of Deriving Information on Surface Conditions from COlumn and VERtically Resolved Observations Relevant to Air Quality (DISCOVER-AQ). The ICARTT file format has been endorsed as a standard format for airborne data by the Standard Process Group (SPG), one of the Earth Science Data Systems Working Groups (ESDSWG) in 2010. The detailed description of the ICARTT format can be found at http://www-air.larc.nasa.gov/missions/etc/ESDS-RFC-019-v1.00.pdf. The ICARTT data format is an ASCII, comma delimited format that was based on the NASA Ames and GTE file formats. The file header is detailed enough to fully describe the data for users outside of the instrument group and includes a description of the meta data. The ICARTT scanning tools, format structure, implementations, and examples will be presented.

  6. Planet Formation

    NASA Astrophysics Data System (ADS)

    Klahr, Hubert; Brandner, Wolfgang

    2011-02-01

    1. Historical notes on planet formation Bodenheimer; 2. The formation and evolution of planetary systems Bouwman et al.; 3. Destruction of protoplanetary disks by photoevaporation Richling, Hollenbach and Yorke; 4. Turbulence in protoplanetary accretion disks Klahr, Rozyczka, Dziourkevitch, Wunsch and Johansen; 5. The origin of solids in the early solar system Trieloff and Palme; 6. Experiments on planetesimal formation Wurm and Blum; 7. Dust coagulation in protoplanetary disks Henning, Dullemond, Wolf and Dominik; 8. The accretion of giant planet cores Thommes and Duncan; 9. Planetary transits: direct vision of extrasolar planets Lecavelier des Etangs and Vidal-Madjar; 10. The core accretion - gas capture model Hubickyj; 11. Properties of exoplanets Marcy, Fischer, Butler and Vogt; 12. Giant planet formation: theories meet observations Boss; 13. From hot Jupiters to hot Neptures … and below Lovis, Mayor and Udry; 14. Disk-planet interaction and migration Masset and Kley; 15. The Brown Dwarf - planet relation Bate; 16. From astronomy to astrobiology Brandner; 17. Overview and prospective Lin.

  7. Ramp-style deposition of Oligocene Marine Vedder formation, San Joaquin Valley, California

    SciTech Connect

    Bloch, R.B.

    1986-04-01

    The Oligocene Vedder formation consists of well-sorted medium to fine-grained marine sand and shale in the subsurface of the eastern San Joaquin Valley. Updip, this formation interfingers with nonmarine/lagoonal facies known as the Walker Formation. This relationship appears to be transgressive because the marine Vedder generally overlies the Walker Formation. Downdip, the Vedder sands interfinger with middle to lower bathyal shale in a progradational manner, forming upward-coarsening patterns in well logs. Depositional water depths for the shale were determined from benthic foraminifera assemblages. The Vedder formation is approximately 750 ft thick along its updip part, and gradually thickens to 1500 ft downdip. Overall deposition geometry, determined from well-log correlations and seismic data, is generally parallel and downlapping. A prominent shelf-slope break is not evident. Rather, depositional surfaces are tabular or broadly lobate, with a depositional slope of 5/sup 0/-10/sup 0/. This geometry of constant slope between nonmarine and deep marine water depth is termed a ramp. The depositional style and geometry are similar to that of the Oligocene upper Pleito Formation, which crops out in the San Emigdio Mountains on the southern margin of the San Joaquin Valley. The Vedder formation was deposited subsequent to a period of rapid subsidence (about 50 cm/1000 years), as determined from geohistory analysis of well data on the Bakersfield arch. This rapid subsidence may have induced deposition in a ramp geometry, rather than a shelf-slope configuration.

  8. Galaxy formation.

    PubMed

    Peebles, P J

    1998-01-01

    It is argued that within the standard Big Bang cosmological model the bulk of the mass of the luminous parts of the large galaxies likely had been assembled by redshift z approximately 10. Galaxy assembly this early would be difficult to fit in the widely discussed adiabatic cold dark matter model for structure formation, but it could agree with an isocurvature version in which the cold dark matter is the remnant of a massive scalar field frozen (or squeezed) from quantum fluctuations during inflation. The squeezed field fluctuations would be Gaussian with zero mean, and the distribution of the field mass therefore would be the square of a random Gaussian process. This offers a possibly interesting new direction for the numerical exploration of models for cosmic structure formation.

  9. Galaxy formation

    PubMed Central

    Peebles, P. J. E.

    1998-01-01

    It is argued that within the standard Big Bang cosmological model the bulk of the mass of the luminous parts of the large galaxies likely had been assembled by redshift z ∼ 10. Galaxy assembly this early would be difficult to fit in the widely discussed adiabatic cold dark matter model for structure formation, but it could agree with an isocurvature version in which the cold dark matter is the remnant of a massive scalar field frozen (or squeezed) from quantum fluctuations during inflation. The squeezed field fluctuations would be Gaussian with zero mean, and the distribution of the field mass therefore would be the square of a random Gaussian process. This offers a possibly interesting new direction for the numerical exploration of models for cosmic structure formation. PMID:9419326

  10. Overview of the mineralogy of the Biwabik Iron Formation, Mesabi Iron Range, northern Minnesota.

    PubMed

    McSwiggen, Peter L; Morey, G B

    2008-10-01

    The mineralogy of the Biwabik Iron Formation changes dramatically from west to east as the formation nears the basal contact of the Duluth Complex. This reflects a contact metamorphism that took place with the emplacement of the igneous Duluth Complex at temperatures as high as 1200 degrees C. However, the mineralogy of the Biwabik Iron Formation also varies vertically through the stratigraphy of the unit. This variability in both the vertical and horizontal dimensions makes it difficult to predict exact horizons where specific minerals will occur. The iron-formation has been subdivided into four broad stratigraphic units (lower cherty, lower slaty, upper cherty, and upper slaty) and into four lateral mineralogical zones (1-4). Zone 1, the westernmost zone, is characterized by quartz, magnetite, hematite, carbonates, talc, chamosite, greenalite, minnesotaite, and stilpnomelane. The silicate mineralogy in Zone 2 of the Biwabik Iron Formation changes very little. However, the minerals begin to change dramatically in Zone 3. Most significantly, Zone 3 is characterized by the appearance of grunerite in both a tabular form and a fibrous form. In Zone 4, the original silicate minerals have completely reacted, and a new suite of minerals occupies the iron-formation. These include grunerite, hornblende, hedenbergite, ferrohypersthene (ferrosilite), and fayalite. PMID:18069109

  11. Amphiplex Formation

    NASA Astrophysics Data System (ADS)

    Petersen, Shannon; Laaser, Jennifer; Lodge, Timothy

    2015-03-01

    Polymer-micelle complexes are currently under heavy investigation due to their potential applications in targeted drug delivery and gene therapy, yet the dynamics of the complex formation is still relatively unstudied. By varying the ratios of poly(styrene sulfonate) chains and cationic poly(dimethylaminoethyl methacrylate)-b-poly(styrene) micelles and the ionic strength of the system, we created a variety of complex configurations of different sizes and charges. The complexes were characterized dynamic light scattering and zeta potential measurements which provided information regarding the hydrodynamic radius, distribution of sizes, and effective charge.

  12. Habit formation

    PubMed Central

    Smith, Kyle S.; Graybiel, Ann M.

    2016-01-01

    Habits, both good ones and bad ones, are pervasive in animal behavior. Important frameworks have been developed to understand habits through psychological and neurobiological studies. This work has given us a rich understanding of brain networks that promote habits, and has also helped us to understand what constitutes a habitual behavior as opposed to a behavior that is more flexible and prospective. Mounting evidence from studies using neural recording methods suggests that habit formation is not a simple process. We review this evidence and take the position that habits could be sculpted from multiple dissociable changes in neural activity. These changes occur across multiple brain regions and even within single brain regions. This strategy of classifying components of a habit based on different brain signals provides a potentially useful new way to conceive of disorders that involve overly fixed behaviors as arising from different potential dysfunctions within the brain's habit network. PMID:27069378

  13. Habit formation.

    PubMed

    Smith, Kyle S; Graybiel, Ann M

    2016-03-01

    Habits, both good ones and bad ones, are pervasive in animal behavior. Important frameworks have been developed to understand habits through psychological and neurobiological studies. This work has given us a rich understanding of brain networks that promote habits, and has also helped us to understand what constitutes a habitual behavior as opposed to a behavior that is more flexible and prospective. Mounting evidence from studies using neural recording methods suggests that habit formation is not a simple process. We review this evidence and take the position that habits could be sculpted from multiple dissociable changes in neural activity. These changes occur across multiple brain regions and even within single brain regions. This strategy of classifying components of a habit based on different brain signals provides a potentially useful new way to conceive of disorders that involve overly fixed behaviors as arising from different potential dysfunctions within the brain's habit network.

  14. Pattern Formation

    NASA Astrophysics Data System (ADS)

    Hoyle, Rebecca

    2006-03-01

    From the stripes of a zebra and the spots on a leopard's back to the ripples on a sandy beach or desert dune, regular patterns arise everywhere in nature. The appearance and evolution of these phenomena has been a focus of recent research activity across several disciplines. This book provides an introduction to the range of mathematical theory and methods used to analyse and explain these often intricate and beautiful patterns. Bringing together several different approaches, from group theoretic methods to envelope equations and theory of patterns in large-aspect ratio-systems, the book also provides insight behind the selection of one pattern over another. Suitable as an upper-undergraduate textbook for mathematics students or as a fascinating, engaging, and fully illustrated resource for readers in physics and biology, Rebecca Hoyle's book, using a non-partisan approach, unifies a range of techniques used by active researchers in this growing field. Accessible description of the mathematical theory behind fascinating pattern formation in areas such as biology, physics and materials science Collects recent research for the first time in an upper level textbook Features a number of exercises - with solutions online - and worked examples

  15. Barrier Formation

    PubMed Central

    Lyaruu, D.M.; Medina, J.F.; Sarvide, S.; Bervoets, T.J.M.; Everts, V.; DenBesten, P.; Smith, C.E.; Bronckers, A.L.J.J.

    2014-01-01

    Enamel fluorosis is an irreversible structural enamel defect following exposure to supraoptimal levels of fluoride during amelogenesis. We hypothesized that fluorosis is associated with excess release of protons during formation of hypermineralized lines in the mineralizing enamel matrix. We tested this concept by analyzing fluorotic enamel defects in wild-type mice and mice deficient in anion exchanger-2a,b (Ae2a,b), a transmembrane protein in maturation ameloblasts that exchanges extracellular Cl− for bicarbonate. Defects were more pronounced in fluorotic Ae2a,b−/− mice than in fluorotic heterozygous or wild-type mice. Phenotypes included a hypermineralized surface, extensive subsurface hypomineralization, and multiple hypermineralized lines in deeper enamel. Mineral content decreased in all fluoride-exposed and Ae2a,b−/− mice and was strongly correlated with Cl−. Exposure of enamel surfaces underlying maturation-stage ameloblasts to pH indicator dyes suggested the presence of diffusion barriers in fluorotic enamel. These results support the concept that fluoride stimulates hypermineralization at the mineralization front. This causes increased release of protons, which ameloblasts respond to by secreting more bicarbonates at the expense of Cl− levels in enamel. The fluoride-induced hypermineralized lines may form barriers that impede diffusion of proteins and mineral ions into the subsurface layers, thereby delaying biomineralization and causing retention of enamel matrix proteins. PMID:24170372

  16. Domino: Extracting, Comparing, and Manipulating Subsets across Multiple Tabular Datasets

    PubMed Central

    Gratzl, Samuel; Gehlenborg, Nils; Lex, Alexander; Pfister, Hanspeter; Streit, Marc

    2016-01-01

    Answering questions about complex issues often requires analysts to take into account information contained in multiple interconnected datasets. A common strategy in analyzing and visualizing large and heterogeneous data is dividing it into meaningful subsets. Interesting subsets can then be selected and the associated data and the relationships between the subsets visualized. However, neither the extraction and manipulation nor the comparison of subsets is well supported by state-of-the-art techniques. In this paper we present Domino, a novel multiform visualization technique for effectively representing subsets and the relationships between them. By providing comprehensive tools to arrange, combine, and extract subsets, Domino allows users to create both common visualization techniques and advanced visualizations tailored to specific use cases. In addition to the novel technique, we present an implementation that enables analysts to manage the wide range of options that our approach offers. Innovative interactive features such as placeholders and live previews support rapid creation of complex analysis setups. We introduce the technique and the implementation using a simple example and demonstrate scalability and effectiveness in a use case from the field of cancer genomics. PMID:26356916

  17. Developments in western Canada in 1979. [Tabular data and maps

    SciTech Connect

    Hay, P.W.

    1980-09-01

    In 1979, another all-time drilling record was set in Western Canada, with 7387 wells being drilled, an increase of 7% over 1978. Exploratory drilling decreased slightly to 2884 wells, down 5%, but development drilling reached record numbers, with 4503 wells, up 17% from 1978. The exploratory success rate was significantly higher at 63% in 1979, based on 713 oil discoveries and 1101 gas discoveries. The development success rate stayed constant at 88%, from 1597 oil discoveries and 2349 gas discoveries. Records were set in average well depths and average land prices paid in Alberta and British Columbia. The most significant event in petroleum exploration in Western Canada for many years was the massive Kopanoar oil discovery in the Beaufort Sea, with estimated flow rates of 1900 cu m/d (12,000 b/d) of 28/sup 0/ sweet crude. A major Arctic Island gas discovery was also made in the Whitefish well near Drake Point. Alberta activity shifted into the deeper Alberta basin and foothills, with oil and gas discoveries south of Calgary at Claresholm, gas discoveries in the central foothills at Erith-Hanlan, Blackstone, and Brown Creek, and oil discoveries farther north in the deep-basin area at Wembley and Beaverlodge. A record $28.2 million bonus (or $8,400/ha) was paid for a single license in the Beaverlodge Triassic oil play by Esso and Pan-Canadian. Deep-basin development drilling in the tight Cretaceous sandstones continued in the Cutbank oil play and Elmworth gas trend, with emphasis on the westward extension of Elmworth into British Columbia. In eastern Alberta, shallow gas exploration is proceeding strongly at Suffield and Primrose Lake. Major British Columbia gas strikes were made in the southwest corner of the explored area at Sukunka and Monias. In southeast Saskatchewan, a Mississippian oil strike was made at Tatagwa.

  18. [Tabular excel editor for analysis of aligned nucleotide sequences].

    PubMed

    Demkin, V V

    2010-01-01

    Excel platform was used for transition of results of multiple aligned nucleotide sequences obtained using the BLAST network service to the form appropriate for visual analysis and editing. Two macros operators for MS Excel 2007 were constructed. The array of aligned sequences transformed into Excel table and processed using macros operators is more appropriate for analysis than initial html data.

  19. Spatial data in geographic information system format on agricultural chemical use, land use, cropping practices in the United States

    USGS Publications Warehouse

    Battaglin, W.A.; Goolsby, D.A.

    1995-01-01

    The spatial data in geographic information system format described in this report consist of estimates for all counties in the conterminous United States of the annual use of 96 herbicides in 1989; annual sales of nitrogen fertilizer, in tons, for 1985-91; and agricultural expenses, land use, chemical use, livestock holdings, and cropping practices in 1987. The source information, originally in tabular form, is summarized as digital polygon attribute data in the 18 geographic information system spatial data layers (coverages) provided. The information in these coverages can be used in estimating regional agricultural-chemical use or agricultural practices and in producing visual displays and mapping relative rates of agricultural-chemical use or agricultural practices across broad regions of the United States.

  20. Formation of the enigmatic Matoush uranium deposit in the Paleoprotozoic Otish Basin, Quebec, Canada

    NASA Astrophysics Data System (ADS)

    Alexandre, Paul; Kyser, Kurt; Layton-Matthews, Daniel; Beyer, Steve R.; Hiatt, Eric E.; Lafontaine, Jonathan

    2015-10-01

    The Matoush uranium deposit is situated in the Paleoproterozoic Otish Basin, northern Quebec, Canada, and is hosted by the Indicator Formation sandstones. Its sheet-like ore bodies are closely associated with the steeply dipping Matoush Fracture, which hosts mafic dykes and minor quartz-feldspar-tourmaline pegmatites. Regional diagenesis, involving oxidizing basinal fluids (δ2H ˜-15‰, δ18O ˜8‰), produced mostly illite and possibly leached U from accessory phases in the Indicator Formation sandstones. The bimodal Matoush dyke intruded the Indicator Formation along the Matoush Fracture, and the related metasomatism produced Cr-rich dravite and muscovite in both the dyke and the proximal sandstones. Uraninite formed when U6+ in the basinal brine was reduced to U4+ in contact with the mafic dyke and by Fe2+ in Cr-dravite and Cr-muscovite, and precipitated together with eskolaite and hematite. Because of its unique characteristics, the Matoush deposit cannot be easily classified within the generally accepted classification of uranium deposits. Two of its main characteristics (unusual reduction mechanism, structural control) do not correspond to the sandstone-hosted group of deposits (unconformity type, tabular, roll front), in spite of uranium being derived from the Otish Group sandstones.

  1. Modeling of the merging, liner formation, implosion of hypervelocity plasma jets for the PLX- α project

    NASA Astrophysics Data System (ADS)

    Cassibry, Jason; Hsu, Scott; Schillo, Kevin; Samulyak, Roman; Stoltz, Peter; Beckwith, Kris

    2015-11-01

    A suite of numerical tools will support the conical and 4 π plasma-liner-formation experiments for the PLX- α project. A new Lagrangian particles (LP) method will provide detailed studies of the merging of plasma jets and plasma-liner formation/convergence. A 3d smooth particle hydrodynamic (SPH) code will simulate conical (up to 9 jets) and 4 π spherical (up to 60 jets) liner formation and implosion. Both LP and SPH will use the same tabular EOS generated by Propaceos, thermal conductivity, optically thin radiation and physical viscosity models. With LP and SPH,the major objectives are to study Mach-number degradation during jet merging, provide RMS amplitude and wave number of the liner nonuniformity at the leading edge, and develop scaling laws for ram pressure and liner uniformity as a function of jet parameters. USIM, a 3D multi-fluid plasma code, will be used to perform 1D and 2D simulations of plasma-jet-driven magneto-inertial fusion (PJMIF) to identify initial conditions in which the ``liner gain'' exceeds unity. A brief overview of the modeling program will be provided. Results from SPH modeling to support the PLX- α experimental design will also be presented, including preliminary ram-pressure scaling and non-uniformity characterization.

  2. Initial development and performance evaluation of a process for formation of dense carbon by pyrolysis of methane

    NASA Technical Reports Server (NTRS)

    Noyes, G. P.; Cusick, R. J.

    1985-01-01

    The three steps in pyrolytic carbon formation are: (1) gaseous hydrocarbon polymerization and aromatic formation; (2) gas-phase condensation and surface adsorption/impingement of polyaromatic hydrocarbon; and (3) final dehydration to carbon. The structure of the carbon in the various stages of formation is examined. The apparatuses and experimental procedures for the pyrolysis of methane in a 60 cm long quartz reactor tube at temperatures ranging from 1400-1600 K are described. The percentage of carbon converted and its density are calculated and tabularly presented. The results reveal that dense carbon formation is maximized and soot eliminated by this procedure. It is observed that conversion efficiency depends on the composition of the inlet gas and conversion increases with increasing temperature. Based on the experimental data a three-man carbon reactor subsystem (CRS) is developed; the functions of the Sabatier Methanation Reactor, two carbon formation reactors and fluid handling components of the CRS are analyzed. The CRS forms 16 kg of carbon at a rate of 0.8 kg/day for 20 days in a two percent volume density quartz wool packing at temperature of 1500-1600 K.

  3. BOREAS RSS-3 Reflectance Measured from a Helicopter-Mounted Barnes MMR

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G. (Editor); Nickeson, Jaime (Editor); Walthall, Charles L.; Loechel, Sara; deColstoun, Eric Brown

    2000-01-01

    The BOREAS RSS-3 team acquired helicopter-based radiometric measurements of forested sites with a Barnes MMR. The data were collected in 1994 during the three BOREAS IFCs at numerous tower and auxiliary sites in both the NSA and SSA. The 15-degree FOV of the MMR yielded approximately 79-m ground resolution from an altitude of 300 m. The MMR has seven spectral bands that are similar to the Landsat TM bands, ranging from the blue region to the thermal. The data are stored in tabular ASCII files. The data are stored in tabular ASCII files.

  4. Common File Formats.

    PubMed

    Mills, Lauren

    2014-03-21

    An overview of the many file formats commonly used in bioinformatics and genome sequence analysis is presented, including various data file formats, alignment file formats, and annotation file formats. Example workflows illustrate how some of the different file types are typically used.

  5. Formate Formation and Formate Conversion in Biological Fuels Production

    PubMed Central

    Crable, Bryan R.; Plugge, Caroline M.; McInerney, Michael J.; Stams, Alfons J. M.

    2011-01-01

    Biomethanation is a mature technology for fuel production. Fourth generation biofuels research will focus on sequestering CO2 and providing carbon-neutral or carbon-negative strategies to cope with dwindling fossil fuel supplies and environmental impact. Formate is an important intermediate in the methanogenic breakdown of complex organic material and serves as an important precursor for biological fuels production in the form of methane, hydrogen, and potentially methanol. Formate is produced by either CoA-dependent cleavage of pyruvate or enzymatic reduction of CO2 in an NADH- or ferredoxin-dependent manner. Formate is consumed through oxidation to CO2 and H2 or can be further reduced via the Wood-Ljungdahl pathway for carbon fixation or industrially for the production of methanol. Here, we review the enzymes involved in the interconversion of formate and discuss potential applications for biofuels production. PMID:21687599

  6. Comparison of abundances of chemical elements in mineralized and unmineralized sandstone of the Brushy Basin Member of the Morrison Formation, Smith Lake District, Grants uranium region, New Mexico

    USGS Publications Warehouse

    Pierson, C.T.; Spirakis, C.S.; Robertson, J.F.

    1983-01-01

    Statistical treatment of analytical data from the Mariano Lake and Ruby uranium deposits in the Smith Lake district, New Mexico, indicates that organic carbon, arsenic, barium, calcium, cobalt, copper, gallium, iron, lead, manganese, molybdenum, nickel, selenium, strontium, sulfur, vanadium, yttrium, and zirconium are concentrated along with uranium in primary ore. Comparison of the Smith Lake data with information from other primary deposits in the Grants uranium region and elsewhere in the Morrison Formation of the Colorado Plateau suggests that these elements, with the possible exceptions of zirconium and gallium and with the probable addition of aluminum and magnesium, are typically associated with primary, tabular uranium deposits. Chemical differences between the Ruby and Mariano Lake deposits are consistent with the interpretation that the Ruby deposit has been more affected by post-mineralization oxidizing solutions than has the Mariano Lake deposit.

  7. The Stratigraphic Expression of Formative Processes in Channels

    NASA Astrophysics Data System (ADS)

    Hubbard, S. M.; Covault, J. A.; Fildani, A.; Romans, B.

    2014-12-01

    The stratigraphic record of sinuous fluvial and deep sea channel deposits contains a wealth of information about formative sedimentary processes. For fluvial systems, deposits are considered in the context of processes observed in rivers, with the point bar facies model, as an example, representing a well-established linkage between process and product. A direct link has not been achieved in the deep sea as direct monitoring of coarse-grained sediment transport is challenging, exacerbated by the sporadic and infrequent nature of flows. Until a method for direct observation is developed and widely applied, the stratigraphic record of sediment transfer in the deep sea provides a critical perspective and unique insight into processes that shape not only ancient basin margin slopes, but also the present day seascape. Despite the obvious similarity in sinuous planforms of open, single thread fluvial and deep sea channels, outcrop characteristics, validated in many instances by experimental and theoretical work, indicate different processes. Meandering fluvial systems are most commonly represented by deposits that reflect point bar migration, a process whereby bank erosion and bar growth are genetically linked. At the bed scale, cross-stratification reflects bedload sediment transport and deposition by traction sedimentation. Single thread deep sea channel-fill strata are commonly characterized by sandstone-filled channelform bodies, which reflect both traction and suspension sedimentation. Heterolithic thin beds and cross-stratification can be locally preserved above channel bases and against channel margins, but the majority of depositional thickness comprises tabular sandstone turbidites that bi-directionally lap onto channel edges. The stratal record indicates a distinction between phases of channel maintenance (e.g., erosion, sediment bypass) and phases of substantial infilling with coarse-grained sediment - they are not contemporaneous. This is a key departure from

  8. The Format Dilemma.

    ERIC Educational Resources Information Center

    Oder, Norman

    2002-01-01

    Reports results of a survey of public libraries that investigated trends in audiovisual materials. Highlights include format issues; audiobooks; media budgets for various formats; video collections; DVDs; circulation; collection sizes; music CDs; and future possibilities. (LRW)

  9. Star Formation in Galaxies

    NASA Technical Reports Server (NTRS)

    1987-01-01

    Topics addressed include: star formation; galactic infrared emission; molecular clouds; OB star luminosity; dust grains; IRAS observations; galactic disks; stellar formation in Magellanic clouds; irregular galaxies; spiral galaxies; starbursts; morphology of galactic centers; and far-infrared observations.

  10. RAMPRF: A program for synchronous acceleration

    SciTech Connect

    Furman, M.A.

    1991-05-01

    We describe a family of standard FORTRAN programs that calculate bucket-related quantities as a function of time during acceleration, assuming it is adiabatic. The members of the family are distinguished by the type of input: One family member takes energy and total peak voltage as a function of time; another takes momentum and bucket area as a function of time, etc. The input is in free-format tabular form. The output is in standard ASCII form, in multi-column tables and x-y listings appropriate for plotting. Bunch-related quantities, such as energy spread and space-charge tune spread, are also calculated assuming that the bunches have a specified longitudinal emittance, and are small and matched to the bucket. Sample excitation curves for the SSC's low energy booster are presented. 4 refs., 2 figs.

  11. BOREAS RSS-17 Stem, Soil, and Air Temperature Data

    NASA Technical Reports Server (NTRS)

    Zimmerman, Reiner; McDonald, Kyle C.; Way, JoBea; Hall, Forrest G. (Editor); Nickeson, Jaime (Editor); Smith, David E. (Technical Monitor)

    2000-01-01

    The BOREAS RSS-17 team collected several data sets in support of its research in monitoring and analyzing environmental and phenological states using radar data. This data set consists of tree bole and soil temperature measurements from various BOREAS flux tower sites. Temperatures were measured with thermistors implanted in the hydroconductive tissue of the trunks of several trees at each site and at various depths in the soil. Data were stored on a data logger at intervals of either 1 or 2 hours. The majority of the data were acquired between early 1994 and early 1995. The primary product of this data set is the diurnal stem temperature measurements acquired for selected trees at five BOREAS tower sites. The data are provided in tabular ASCII format. The data files are available on a CD-ROM (see document number 20010000884) or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

  12. Simple Ontology Format (SOFT)

    SciTech Connect

    Sorokine, Alexandre

    2011-10-01

    Simple Ontology Format (SOFT) library and file format specification provides a set of simple tools for developing and maintaining ontologies. The library, implemented as a perl module, supports parsing and verification of the files in SOFt format, operations with ontologies (adding, removing, or filtering of entities), and converting of ontologies into other formats. SOFT allows users to quickly create ontologies using only a basic text editor, verify it, and portray it in a graph layout system using customized styles.

  13. Record Formatting: MARC AMC.

    ERIC Educational Resources Information Center

    Weber, Lisa B.

    1990-01-01

    Discusses how archivists use the MARC AMC (Archival and Manuscripts Control) format for descriptive information about archival materials. Modifications that MARC AMC introduced to the standard MARC bibliographic formats are explained, and examples of a record in AMC formats on different bibliographic utilities are given. (24 references) (LRW)

  14. Formation Conditions and Sedimentary Characteristics of a Triassic Shallow Water Braided Delta in the Yanchang Formation, Southwest Ordos Basin, China.

    PubMed

    Liu, Ziliang; Shen, Fang; Zhu, Xiaomin; Li, Fengjie; Tan, Mengqi

    2015-01-01

    A large, shallow braided river delta sedimentary system developed in the Yanchang Formation during the Triassic in the southwest of the Ordos basin. In this braided delta system, abundant oil and gas resources have been observed, and the area is a hotspot for oil and gas resource exploration. Through extensive field work on outcrops and cores and analyses of geophysical data, it was determined that developments in the Late Triassic produced favorable geological conditions for the development of shallow water braided river deltas. Such conditions included a large basin, flat terrain, and wide and shallow water areas; wet and dry cyclical climate changes; ancient water turbulence; dramatic depth cycle changes; ancient uplift development; strong weathering of parent rock; and abundant supply. The shallow water braided river delta showed grain sediment granularity, plastic debris, and sediment with mature composition and structure that reflected the strong hydrodynamic environment of large tabular cross-bedding, wedge cross-bedding, and multiple positive rhythms superimposed to form a thick sand body layer. The branch river bifurcation developed underwater, and the thickness of the sand body increased further, indicating that the slope was slow and located in shallow water. The seismic responses of the braided river delta reflected strong shallow water performance, indicated by a progradation seismic reflection phase axis that was relatively flat; in addition, the seismic reflection amplitude was strong and continuous with a low angle and extended over considerable distances (up to 50 km). The sedimentary center was close to the provenance, the width of the river was large, and a shallow sedimentary structure and a sedimentary rhythm were developed. The development of the delta was primarily controlled by tectonic activity and changes in the lake level; as a result, the river delta sedimentary system eventually presented a "small plain, big front" character. PMID

  15. Formation Conditions and Sedimentary Characteristics of a Triassic Shallow Water Braided Delta in the Yanchang Formation, Southwest Ordos Basin, China

    PubMed Central

    Liu, Ziliang; Shen, Fang; Zhu, Xiaomin; Li, Fengjie; Tan, Mengqi

    2015-01-01

    A large, shallow braided river delta sedimentary system developed in the Yanchang Formation during the Triassic in the southwest of the Ordos basin. In this braided delta system, abundant oil and gas resources have been observed, and the area is a hotspot for oil and gas resource exploration. Through extensive field work on outcrops and cores and analyses of geophysical data, it was determined that developments in the Late Triassic produced favorable geological conditions for the development of shallow water braided river deltas. Such conditions included a large basin, flat terrain, and wide and shallow water areas; wet and dry cyclical climate changes; ancient water turbulence; dramatic depth cycle changes; ancient uplift development; strong weathering of parent rock; and abundant supply. The shallow water braided river delta showed grain sediment granularity, plastic debris, and sediment with mature composition and structure that reflected the strong hydrodynamic environment of large tabular cross-bedding, wedge cross-bedding, and multiple positive rhythms superimposed to form a thick sand body layer. The branch river bifurcation developed underwater, and the thickness of the sand body increased further, indicating that the slope was slow and located in shallow water. The seismic responses of the braided river delta reflected strong shallow water performance, indicated by a progradation seismic reflection phase axis that was relatively flat; in addition, the seismic reflection amplitude was strong and continuous with a low angle and extended over considerable distances (up to 50 km). The sedimentary center was close to the provenance, the width of the river was large, and a shallow sedimentary structure and a sedimentary rhythm were developed. The development of the delta was primarily controlled by tectonic activity and changes in the lake level; as a result, the river delta sedimentary system eventually presented a “small plain, big front” character. PMID

  16. Formation Conditions and Sedimentary Characteristics of a Triassic Shallow Water Braided Delta in the Yanchang Formation, Southwest Ordos Basin, China.

    PubMed

    Liu, Ziliang; Shen, Fang; Zhu, Xiaomin; Li, Fengjie; Tan, Mengqi

    2015-01-01

    A large, shallow braided river delta sedimentary system developed in the Yanchang Formation during the Triassic in the southwest of the Ordos basin. In this braided delta system, abundant oil and gas resources have been observed, and the area is a hotspot for oil and gas resource exploration. Through extensive field work on outcrops and cores and analyses of geophysical data, it was determined that developments in the Late Triassic produced favorable geological conditions for the development of shallow water braided river deltas. Such conditions included a large basin, flat terrain, and wide and shallow water areas; wet and dry cyclical climate changes; ancient water turbulence; dramatic depth cycle changes; ancient uplift development; strong weathering of parent rock; and abundant supply. The shallow water braided river delta showed grain sediment granularity, plastic debris, and sediment with mature composition and structure that reflected the strong hydrodynamic environment of large tabular cross-bedding, wedge cross-bedding, and multiple positive rhythms superimposed to form a thick sand body layer. The branch river bifurcation developed underwater, and the thickness of the sand body increased further, indicating that the slope was slow and located in shallow water. The seismic responses of the braided river delta reflected strong shallow water performance, indicated by a progradation seismic reflection phase axis that was relatively flat; in addition, the seismic reflection amplitude was strong and continuous with a low angle and extended over considerable distances (up to 50 km). The sedimentary center was close to the provenance, the width of the river was large, and a shallow sedimentary structure and a sedimentary rhythm were developed. The development of the delta was primarily controlled by tectonic activity and changes in the lake level; as a result, the river delta sedimentary system eventually presented a "small plain, big front" character.

  17. Medical image file formats.

    PubMed

    Larobina, Michele; Murino, Loredana

    2014-04-01

    Image file format is often a confusing aspect for someone wishing to process medical images. This article presents a demystifying overview of the major file formats currently used in medical imaging: Analyze, Neuroimaging Informatics Technology Initiative (Nifti), Minc, and Digital Imaging and Communications in Medicine (Dicom). Concepts common to all file formats, such as pixel depth, photometric interpretation, metadata, and pixel data, are first presented. Then, the characteristics and strengths of the various formats are discussed. The review concludes with some predictive considerations about the future trends in medical image file formats.

  18. Medical image file formats.

    PubMed

    Larobina, Michele; Murino, Loredana

    2014-04-01

    Image file format is often a confusing aspect for someone wishing to process medical images. This article presents a demystifying overview of the major file formats currently used in medical imaging: Analyze, Neuroimaging Informatics Technology Initiative (Nifti), Minc, and Digital Imaging and Communications in Medicine (Dicom). Concepts common to all file formats, such as pixel depth, photometric interpretation, metadata, and pixel data, are first presented. Then, the characteristics and strengths of the various formats are discussed. The review concludes with some predictive considerations about the future trends in medical image file formats. PMID:24338090

  19. Interstratified arkosic and volcanic rocks of the Miocene Spanish Canyon Formation, Alvord Mountain area, California: descriptions and interpretations

    USGS Publications Warehouse

    Buesch, David C.

    2014-01-01

    The Spanish Canyon Foundation in the Alvord Mountain area, California, varies from about 50 to 120 m thick and records the interstratification of arkosic sandstone and conglomerate with tuffaceous deposits and lava flows. In the lower third of the formation, arkosic sandstone and conglomerate are interstratified with tuffaceous deposits. Some tuffs might have been deposited as primary, nonwelded to partially welded ignimbrites or fallout tephra. Many of the tuffaceous deposits represent redeposited material that formed tuffaceous sandstone, and many of these deposits contain arkosic grains that represent mixing of different source matieral. Arkosic sandstone, and especially conglomerate (some with maximum clast lengths up to 1 m), represent intermittent incursions of coarser plutoniclastic fan deposits into other finer grained and mostly volcaniclastic basin deposits. After deposition of the 18.78 Ma Peach Spring Tuff, the amount of tuffaceous material decreased. The upper two-thirds of the formation has arkosic sandstone and conglomerate interstratified with two olivine basalt lave flows. locally, conglomerate clasts in this part of the section have maximum lengths up to 1 m. Many tuffaceous and arkosic sandstone beds of the Spanish Canyon Formation have tabular to broad (low-relief) lenticular geometry, and locally, some arkosic conglomerate fills channels as much as 1.5 m deep. These bedforms are consistent with deposition in medial to distal alluvial-fan or fluvial environments; some finer-grained deposits might have formed in lacustrine environments.

  20. The digital geologic map of Colorado in ARC/INFO format, Part B. Common files

    USGS Publications Warehouse

    Green, Gregory N.

    1992-01-01

    This geologic map was prepared as a part of a study of digital methods and techniques as applied to complex geologic maps. The geologic map was digitized from the original scribe sheets used to prepare the published Geologic Map of Colorado (Tweto 1979). Consequently the digital version is at 1:500,000 scale using the Lambert Conformal Conic map projection parameters of the state base map. Stable base contact prints of the scribe sheets were scanned on a Tektronix 4991 digital scanner. The scanner automatically converts the scanned image to an ASCII vector format. These vectors were transferred to a VAX minicomputer, where they were then loaded into ARC/INFO. Each vector and polygon was given attributes derived from the original 1979 geologic map. This database was developed on a MicroVAX computer system using VAX V 5.4 nd ARC/INFO 5.0 software. UPDATE: April 1995, The update was done solely for the purpose of adding the abilitly to plot to an HP650c plotter. Two new ARC/INFO plot AMLs along with a lineset and shadeset for the HP650C design jet printer have been included. These new files are COLORADO.650, INDEX.650, TWETOLIN.E00 and TWETOSHD.E00. These files were created on a UNIX platform with ARC/INFO 6.1.2. Updated versions of INDEX.E00, CONTACT.E00, LINE.E00, DECO.E00 and BORDER.E00 files that included the newly defined HP650c items are also included. * Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Descriptors: The Digital Geologic Map of Colorado in ARC/INFO Format Open-File Report 92-050

  1. The digital geologic map of Colorado in ARC/INFO format, Part A. Documentation

    USGS Publications Warehouse

    Green, Gregory N.

    1992-01-01

    This geologic map was prepared as a part of a study of digital methods and techniques as applied to complex geologic maps. The geologic map was digitized from the original scribe sheets used to prepare the published Geologic Map of Colorado (Tweto 1979). Consequently the digital version is at 1:500,000 scale using the Lambert Conformal Conic map projection parameters of the state base map. Stable base contact prints of the scribe sheets were scanned on a Tektronix 4991 digital scanner. The scanner automatically converts the scanned image to an ASCII vector format. These vectors were transferred to a VAX minicomputer, where they were then loaded into ARC/INFO. Each vector and polygon was given attributes derived from the original 1979 geologic map. This database was developed on a MicroVAX computer system using VAX V 5.4 nd ARC/INFO 5.0 software. UPDATE: April 1995, The update was done solely for the purpose of adding the abilitly to plot to an HP650c plotter. Two new ARC/INFO plot AMLs along with a lineset and shadeset for the HP650C design jet printer have been included. These new files are COLORADO.650, INDEX.650, TWETOLIN.E00 and TWETOSHD.E00. These files were created on a UNIX platform with ARC/INFO 6.1.2. Updated versions of INDEX.E00, CONTACT.E00, LINE.E00, DECO.E00 and BORDER.E00 files that included the newly defined HP650c items are also included. * Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Descriptors: The Digital Geologic Map of Colorado in ARC/INFO Format Open-File Report 92-050

  2. The digital geologic map of Colorado in ARC/INFO format

    USGS Publications Warehouse

    Green, Gregory N.

    1992-01-01

    This geologic map was prepared as a part of a study of digital methods and techniques as applied to complex geologic maps. The geologic map was digitized from the original scribe sheets used to prepare the published Geologic Map of Colorado (Tweto 1979). Consequently the digital version is at 1:500,000 scale using the Lambert Conformal Conic map projection parameters of the state base map. Stable base contact prints of the scribe sheets were scanned on a Tektronix 4991 digital scanner. The scanner automatically converts the scanned image to an ASCII vector format. These vectors were transferred to a VAX minicomputer, where they were then loaded into ARC/INFO. Each vector and polygon was given attributes derived from the original 1979 geologic map. This database was developed on a MicroVAX computer system using VAX V 5.4 nd ARC/INFO 5.0 software. UPDATE: April 1995, The update was done solely for the purpose of adding the abilitly to plot to an HP650c plotter. Two new ARC/INFO plot AMLs along with a lineset and shadeset for the HP650C design jet printer have been included. These new files are COLORADO.650, INDEX.650, TWETOLIN.E00 and TWETOSHD.E00. These files were created on a UNIX platform with ARC/INFO 6.1.2. Updated versions of INDEX.E00, CONTACT.E00, LINE.E00, DECO.E00 and BORDER.E00 files that included the newly defined HP650c items are also included. * Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Descriptors: The Digital Geologic Map of Colorado in ARC/INFO Format Open-File Report 92-050

  3. Star Formation for Predictive Primordial Galaxy Formation

    NASA Astrophysics Data System (ADS)

    Milosavljević, Miloš; Safranek-Shrader, Chalence

    The elegance of inflationary cosmology and cosmological perturbation theory ends with the formation of the first stars and galaxies, the initial sources of light that launched the phenomenologically rich process of cosmic reionization. Here we review the current understanding of early star formation, emphasizing unsolved problems and technical challenges. We begin with the first generation of stars to form after the Big Bang and trace how they influenced subsequent star formation. The onset of chemical enrichment coincided with a sharp increase in the overall physical complexity of star forming systems. Ab-initio computational treatments are just now entering the domain of the predictive and are establishing contact with local observations of the relics of this ancient epoch.

  4. Depositional facies of the Cambrian Araba Formation in the Taba region, east Sinai, Egypt

    NASA Astrophysics Data System (ADS)

    El-Araby, A.; Abdel-Motelib, A.

    1999-10-01

    A thick succession of Cambrian sediments is exposed in the Taba region, east Sinai, and subdivided into the Araba Formation and the overlying Naqus Formation. The vertical and lateral distribution of the Araba Formation in the Taba region provides an outstanding example of an overall retrograding sequence. Three distinctive units (I, II and III) are distinguished within this succession on the basis of depositional geometries, stratified patterns, sedimentary features and petrographic examinations. They record different depositional environments and each unit is distinguished by a particular facies association, which records processes characteristic of these environments. The lower unit (I) is dominated by five depositional facies (la-le) which belong to low sinuosity braided channels associated with floodplain fines and alluvial fans. Channel deposits are represented by tabular cross-bedded and horizontally stratified pebbly coarse-grained sandstones. The middle unit (II) reveals a relative sea level rise and is composed of fine- to coarse-grained sandstone, shale and mudstone with carbonate intercalcations. From four depositional facies (Ila-Ild), recognised facies (Ila, Ilc and Ild) are comparable to upper-lower shoreface and tidal channel environments. The fourth facies (Ilb) is carbonate-dominated with trilobite tracks, and reflects deposition in the upper-middle intertidal flat. The latter facies (llb) is subjected to intea-Cambrian karstification, which is deduced from the presence of macro- and microscopic fresh water calcite fillings, botryoidal Fe and Mn oxides and terra rossa. The uppermost unit (III) is shale-dominated from the inner shelf and is represented by two facies (Illa and Illb). Despite the general rise in sea-level in the Araba Formation, the uppermost facies (Illb) points to a progradational-upward tendency in unit (III), and this is coeval with an increase in the percentage of interbedded fine-grained sandstones.

  5. The mzTab data exchange format: communicating mass-spectrometry-based proteomics and metabolomics experimental results to a wider audience.

    PubMed

    Griss, Johannes; Jones, Andrew R; Sachsenberg, Timo; Walzer, Mathias; Gatto, Laurent; Hartler, Jürgen; Thallinger, Gerhard G; Salek, Reza M; Steinbeck, Christoph; Neuhauser, Nadin; Cox, Jürgen; Neumann, Steffen; Fan, Jun; Reisinger, Florian; Xu, Qing-Wei; Del Toro, Noemi; Pérez-Riverol, Yasset; Ghali, Fawaz; Bandeira, Nuno; Xenarios, Ioannis; Kohlbacher, Oliver; Vizcaíno, Juan Antonio; Hermjakob, Henning

    2014-10-01

    The HUPO Proteomics Standards Initiative has developed several standardized data formats to facilitate data sharing in mass spectrometry (MS)-based proteomics. These allow researchers to report their complete results in a unified way. However, at present, there is no format to describe the final qualitative and quantitative results for proteomics and metabolomics experiments in a simple tabular format. Many downstream analysis use cases are only concerned with the final results of an experiment and require an easily accessible format, compatible with tools such as Microsoft Excel or R. We developed the mzTab file format for MS-based proteomics and metabolomics results to meet this need. mzTab is intended as a lightweight supplement to the existing standard XML-based file formats (mzML, mzIdentML, mzQuantML), providing a comprehensive summary, similar in concept to the supplemental material of a scientific publication. mzTab files can contain protein, peptide, and small molecule identifications together with experimental metadata and basic quantitative information. The format is not intended to store the complete experimental evidence but provides mechanisms to report results at different levels of detail. These range from a simple summary of the final results to a representation of the results including the experimental design. This format is ideally suited to make MS-based proteomics and metabolomics results available to a wider biological community outside the field of MS. Several software tools for proteomics and metabolomics have already adapted the format as an output format. The comprehensive mzTab specification document and extensive additional documentation can be found online.

  6. Tropical cyclone formation

    SciTech Connect

    Montgomery, M.T.; Farrell, B.F. )

    1993-01-15

    The physics of tropical cyclone formation is not well understood, and more is known about the mature hurricane than the formative mechanisms that produce it. It is believed part of the reason for this can be traced to insufficient upper-level atmospheric data. Recent observations suggest that tropical cyclones are initiated by asymmetric interactions associated with migratory upper-level potential vorticity disturbances and low-level disturbances. Favored theories of cyclones formation, however, focus on internal processes associated with cumulus convection and/or air-sea interaction. This work focuses on external mechanisms of cyclone formation and, using both a two- and three-dimensional moist geostrophic momentum model, investigates the role of upper-level potential vorticity disturbances on the formation process. A conceptual model of tropical cyclone formation is proposed, and implications of the theory are discussed. 71 refs., 5 figs., 1 tab.

  7. Simple Ontology Format (SOFT)

    2011-10-01

    Simple Ontology Format (SOFT) library and file format specification provides a set of simple tools for developing and maintaining ontologies. The library, implemented as a perl module, supports parsing and verification of the files in SOFt format, operations with ontologies (adding, removing, or filtering of entities), and converting of ontologies into other formats. SOFT allows users to quickly create ontologies using only a basic text editor, verify it, and portray it in a graph layoutmore » system using customized styles.« less

  8. GLOBAL STAR FORMATION REVISITED

    SciTech Connect

    Silk, Joseph; Norman, Colin E-mail: norman@stsci.edu

    2009-07-20

    A general treatment of disk star formation is developed from a dissipative multiphase model, with the dominant dissipation due to cloud collisions. The Schmidt-Kennicutt (SK) law emerges naturally for star-forming disks and starbursts. We predict that there should be an inverse correlation between Tully-Fisher law and SK law residuals. The model is extended to include a multiphase treatment of supernova feedback that leads to a turbulent pressure-regulated generalization of the star formation law and is applicable to gas-rich starbursts. Enhanced pressure, as expected in merger-induced star formation, enhances star formation efficiency. An upper limit is derived for the disk star formation rate in starbursts that depends on the ratio of global ISM to cloud pressures. We extend these considerations to the case where the interstellar gas pressure in the inner galaxy is dominated by outflows from a central active galactic nucleus (AGN). During massive spheroid formation, AGN-driven winds trigger star formation, resulting in enhanced supernova feedback and outflows. The outflows are comparable to the AGN-boosted star formation rate and saturate in the super-Eddington limit. Downsizing of both SMBH and spheroids is a consequence of AGN-driven positive feedback. Bondi accretion feeds the central black hole with a specific accretion rate that is proportional to the black hole mass. AGN-enhanced star formation is mediated by turbulent pressure and relates spheroid star formation rate to black hole accretion rate. The relation between black hole mass and spheroid velocity dispersion has a coefficient (Salpeter time to gas consumption time ratio) that provides an arrow of time. Highly efficient, AGN-boosted star formation can occur at high redshift.

  9. Lagoonal deposits in the Upper Cretaceous Rock Springs Formation (Mesaverde Group), southwest Wyoming

    USGS Publications Warehouse

    Kirschbaum, M.A.

    1989-01-01

    Most paleogeographic reconstructions of the Rock Springs Formation show shorelines having lobate to arcuate deltas. These shorelines are oriented NE-SW, with the sea to the southeast. Brackish-water bodies are usually shown in interdistributary areas or associated with abandoned delta lobes, and are open to the sea. In this study, a sedimentary sequence 30-50 m thick is interpreted as interdeltaic deposits. Brackish-water deposits within the sequence are interpreted as interdeltaic lagoons rather than interdistributary bays. Three facies associations (units) are recognized in nine measured sections of the study interval. Unit A consists of interbedded sandstone, mudrock and coal which occur in both fining- and coarsening-upward sequences less than 10 m thick. Fining-upward sequences decrease in thickness and frequency upwards in unit A and are interpreted as distributary channels. Coarsening-upward sequences associated with the channels are interpreted as crevasse splays that filled lakes or interdistributary bays. In the upper part of the unit where only minor channels are present, the coarsening-upward sequences are interpreted as bay deltas. Unit B consists of fossiliferous silty shale and bioturbated sandy siltstone. A low-diversity fauna of bivalves, gastropods, ostracods and foraminifers indicates that brackish-water conditions existed. Unit B intertongues with unit A to the northwest and with unit C to the southeast, and is interpreted as lagoonal deposits. Unit C consists of crossbedded and burrowed sandstone in beds 0.5-9 m thick. Sandstones are laterally continuous in the southeast but become tabular bodies enclosed within unit B to the northwest. Laterally continuous sandstones are interpreted as shoreface deposits on the basis of multidirectional crossbeds, marine trace fossils and continuity. Tabular sandstones are interpreted as flood-tidal deltas on the basis of NW-oriented crossbeds, pinchouts to the northwest and enclosure within unit B. Scoured

  10. BOREAS TF-5 SSA-OJP Tower Flux and Meteorological Data

    NASA Technical Reports Server (NTRS)

    Baldocchi, Dennis; Vogel, Christoph; Hall, Forrest G. (Editor); Huemmrich, Karl (Editor)

    2000-01-01

    The BOReal Ecosystem-Atmosphere Study Tower Flux (BOREAS TF-5) team collected tower flux data at the BOREAS Southern Study Area Old Jack Pine (SSA-OJP) site through the growing season of 1994. The data are available in tabular ASCII files.

  11. BOREAS TGB-1/TGB-3 CH4 Chamber Flux Data over the NSA Fen

    NASA Technical Reports Server (NTRS)

    Bubier, Jill L.; Moore, Tim R.; Hall, Forrest G. (Editor); Conrad, Sara K. (Editor)

    2000-01-01

    The BOREAS TGB-3 team collected methane (CH4) chamber flux measurements at the NSA fen site during May-September 1994 and June-October 1996. Gas samples were extracted approximately every 7 days from chambers and analyzed at the NSA lab facility. The data are provided in tabular ASCII files.

  12. BOREAS TGB-10 Volatile Organic Carbon Data over the SSA

    NASA Technical Reports Server (NTRS)

    Westberg, Hal; Hall, Forrest G. (Editor); Conrad, Sara K. (Editor); Hall, Brad; Jackson, Andrea V.

    2000-01-01

    The BOREAS TGB-10 team collected several trace gas data sets in its efforts to determine the role of biogenic hydrocarbon emissions with respect to boreal forest carbon cycles. This data set contains measured VOC concentrations. These data were obtained at the SSA-OJP site from May to September 1994. The data are stored in tabular ASCII files.

  13. BOREAS TF-8 NSA-OJP Tower Flux, Meteorological, and Soil Temperature Data

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G. (Editor); Huemmrich, Karl (Editor); Moore, Kathleen E.; Fitzjarrald, David R.

    2000-01-01

    The BOREAS TF-8 team collected energy, CO2, and water vapor flux data at the BOREAS NSA-OJP site during the growing season of 1994 and most of the year for 1996. The data are available in tabular ASCII files.

  14. BOREAS TF-4 SSA-YJP Tower Flux, Meteorological, and Canopy Condition Data

    NASA Technical Reports Server (NTRS)

    Striegl, Robert; Wickland, Kimberly; Hall, Forrest G. (Editor); Huemmrich, Karl (Editor)

    2000-01-01

    The BOReal Ecosystem-Atmosphere Study Tower Flux (BOREAS TF-4) team collected energy, carbon dioxide, and water vapor flux data at the BOREAS Southern Study Area-Young Jack Pine (SSA-YJP) site during the growing season of 1994. In addition, meteorological data were collected both above and within the canopy. The data are available in tabular ASCII files.

  15. BOREAS TF-1 SSA-OA Tower Flux, Meteorological, and Soil Temperature Data

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G. (Editor); Huemmrich, Karl (Editor); Black, T. Andrew; Chen, Z.; Nesic, Zoran

    2000-01-01

    The BOREAS TF-1 team collected energy, carbon dioxide, and momentum flux data above the canopy along with meteorological and soils data at the BOREAS SSA-OA site from mid-April to the end of the year for 1996. The data are available in tabular ASCII files.

  16. BOREAS TF-1 SSA-OA Understory Flux, Meteorological, and Soil Temperature Data

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G. (Editor); Huemmrich, Karl (Editor); Black, T. Andrew; Chen, Z.; Nesic, Zoran

    2000-01-01

    The BOREAS TF-1 team collected energy, carbon dioxide, and momentum flux data under the canopy along with meteorological and soils data at the BOREAS SSA-OA site from mid-October to mid-November of 1993 and throughout all of 1994. The data are available in tabular ASCII files.

  17. BOREAS TF-7 SSA-OBS Tower Flux and Meteorological Data

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G. (Editor); Huemmrich, Karl (Editor); Pattey, Elizabeth; Desjardins, Raymond L.

    2000-01-01

    The BOREAS TF-7 team collected meteorological data as well as energy, carbon dioxide, water vapor, methane, and nitrous oxide flux data at the BOREAS SSA-OBS site. The data were collected from 24-May to 19-Sep-1994. The data are available in tabular ASCII files.

  18. BOREAS TF-3 NSA-OBS Tower Flux, Meteorological, and Soil Temperature Data

    NASA Technical Reports Server (NTRS)

    Wofsy, Steven; Sutton, Doug; Goulden, Mike; Hall, Forrest G. (Editor); Huemmrich, Karl (Editor)

    2000-01-01

    The BOReal Ecosystem-Atmosphere Study Tower Flux (BOREAS TF-3) team collected tower flux, surface meteorological, and soil temperature data at the BOREAS Northern Study Area-Old Black Spruce (NSA-OBS) site continuously from the March 1994 through October 1996. The data are available in tabular ASCII files.

  19. BOREAS TF-6 SSA-YA Surface Energy Flux and Meteorological Data

    NASA Technical Reports Server (NTRS)

    Bessemoulin, Pierre; Puech, Dominique; Hall, Forrest G. (Editor); Huemmrich, Karl (Editor)

    2000-01-01

    The BOREAS TF-6 team collected surface energy flux and meteorology data at the SSA-YA site. The data characterize the energy flux and meteorological conditions at the site from 18-Jul to 20-Sep-1994. The data set does not contain any trace gas exchange measurements. The data are available in tabular ASCII files.

  20. BOREAS TGB-9 Above-canopy NMHC at SSA-OBS, SSA-OJP, and SSA-OA Sites

    NASA Technical Reports Server (NTRS)

    Keiser, B. N.; Niki, H.; Young, V. L.; Hall, Forrest G. (Editor); Conrad, Sara K. (Editor)

    2000-01-01

    The BOREAS TGB-9 team collected data in order to inventory and quantify the anthropogenic and biogenic NMHCs over the BOREAS study areas. This data set contains concentration and mixing ratio values for several NMHCs collected at the BOREAS SSA from 27-May-1994 to 15-Sep-1994. The data are provided in tabular ASCII files.

  1. BOREAS TF-9 SSA-OBS Tower Flux, Meteorological, and Soil Temperature Data

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G. (Editor); Huemmrich, Karl (Editor); Massheder, Jonathan M.; Moncrieff, John B.; Rayment, Mark B.; Jarvis, Paul G.

    2000-01-01

    The BOREAS TF-9 team collected energy, carbon dioxide, and water vapor flux data at the BOREAS SSA-OBS site during the growing season of 1994 and most of the year for 1996. From the winter of 1995 to 1996, soil temperature data were also collected and provided. The data are available in tabular ASCII files.

  2. Multiwell Experiment final report: 4, The fluvial interval of the Mesaverde Formation

    SciTech Connect

    Not Available

    1990-01-01

    The Department of Energy's Multiwell Experiment (MWX) is a field laboratory in the Piceance Basin of Colorado which has two overall objectives: to characterize the low permeability gas reservoirs in the Mesaverde Formation and to develop technology for their production. Different depositional environments have created distinctly different reservoirs in the Mesaverde, and MWX has addressed each of these in turn. This report presents a comprehensive summary of results from the fluvial interval which lies between 4400 ft and 600 ft at the MWX site. The reservoirs consist of heterogeneous, amalgamated point-bar sequences which form broad meanderbelts which create irregular, but roughly tabular, reservoirs with widths of 1000--2500 ft. Separate sections of this report are background and summary; site descriptions and operations; geology; log analysis; core analysis; in situ stress; well testing, stimulation, fracture diagnostics, and reservoir evaluation in two separate sandstones; stress, fracture diagnostic, and stimulation experiments in an additional sandstone; supporting laboratory studies; and a bibliography. Additional detailed data, results, analyses, and data file references are presented as appendices which are included on microfiche. The results show that stimulation of fluvial reservoirs can be successful if proper care is taken to minimize damage to the natural fracture system. Both an accelerated leakoff phenomenon and the ability to alter the in situ stress were quantified. Overall, the fluvial interval offers the highest production potential of the three nonmarine intervals studied. 141 refs., 92 figs., 33 tabs.

  3. Multiwell Experiment final report: 4, The fluvial interval of the Mesaverde Formation

    SciTech Connect

    Not Available

    1990-01-01

    The Department of Energy's Multiwell Experiment (MWX) is a field laboratory in the Piceance Basin of Colorado which has two overall objectives: to characterize the low permeability gas reservoirs in the Mesaverde Formation and to develop technology for their production. Different depositional environments have created distinctly different reservoirs in the Mesaverde, and MWX has addressed each of these in turn. This report presents a comprehensive summary of results from the fluvial interval which lies between 4400 ft and 6000 ft at the MWX site. The reservoirs consist of heterogeneous, amalgamated point-bar sequences which form broad meanderbelts which create irregular, but roughly tabular, reservoirs with widths of 1000--2500 ft. Separate sections of this report are background and summary; site descriptions and operations; geology; log analysis; core analysis; in situ stress; well testing, stimulation, fracture diagnostics, and reservoir evaluation in two separate sandstones; stress, fracture diagnostic, and stimulation experiments in an additional sandstone; supporting laboratory studies; and a bibliography. Additional detailed data, results, analyses, and data file references are presented as appendices which are included on microfiche. The results show that stimulation of fluvial reservoirs can be successful if proper care is taken to minimize damage to the natural fracture system. Both an accelerated leakoff phenomenon and the ability to alter the in situ stress were quantified. Overall, the fluvial interval offers the highest production potential of the three nonmarine intervals studied. 116 refs., 230 figs., 28 tabs.

  4. [Measuring thrombin formation].

    PubMed

    Hemker, H C

    2016-01-01

    Measurement of thrombin formation makes it possible to estimate the risk of haemorrhage or thrombosis much more accurately than by using clotting time. This new technique allows better monitoring of the effect of prophylactic and therapeutic anticoagulant therapy. Thrombin formation is, however, not yet routinely measured. PMID:27650017

  5. Ice Formation on Wings

    NASA Technical Reports Server (NTRS)

    Ritz, L

    1939-01-01

    This report makes use of the results obtained in the Gottingen ice tunnel in which the atmospheric conditions are simulated and the process of ice formation photographed. The effect of ice formation is threefold: 1) added weight to the airplane; 2) a change in the lift and drag forces; 3) a change in the stability characteristics.

  6. School Formative Feedback Systems

    ERIC Educational Resources Information Center

    Halverson, Richard

    2010-01-01

    Data-driven instructional improvement relies on developing coherent systems that allow school staff to generate, interpret, and act upon quality formative information on students and school programs. This article offers a formative feedback system model that captures how school leaders and teachers structure artifacts and practices to create…

  7. Entering the Formative Years

    ERIC Educational Resources Information Center

    Powers, Keith

    2011-01-01

    This article discusses formative assessment--classroom strategies that ensure students are understanding music concepts. Unlike summative assessments (end-of-process evaluations like final exams, SATs, or auditions), formative assessments need to be non-threatening, helpful, and most of all, effective. The process starts with a teacher…

  8. Formative Assessment Probes

    ERIC Educational Resources Information Center

    Eberle, Francis; Keeley, Page

    2008-01-01

    Formative assessment probes can be effective tools to help teachers build a bridge between students' initial ideas and scientific ones. In this article, the authors describe how using two formative assessment probes can help teachers determine the extent to which students make similar connections between developing a concept of matter and a…

  9. Intergalactic Star Formation

    NASA Astrophysics Data System (ADS)

    Boquien, Médéric

    2007-11-01

    The work presented here is about star formation in the unusual environment of collisional debris studied for the first time as such. These peculiar regions have an interstellar medium, and in particular a metallicity, similar to that of star forming regions in galactic discs while not undergoing similar environment effects such as density waves in the spiral arms for instance. This study has been conducted with a selection of exceptional systems that have ejected large quantities of gas into the intergalactic medium while also showing some intergalactic star forming regions. Principal Investigator as well as archive spectroscopy and imaging from multi-wavelength observations ranging from far ultraviolet to mid-infrared have been used. Withal a model has been built in order to reproduce the spectral energy distributions of intergalactic star forming regions and constrain the star formation histories, their extinctions and their fraction of stars coming from the parent galaxies' discs. Comparisons have been performed on the estimation of star formation rates between infrared, Halpha and ultraviolet wavelengths. This thesis has brought the following main new results: * some regions seem to be deprived of any old stellar population, and these are ideal laboratories in which to study star formation ; * the mid-infrared star formation rate estimator is as reliable as it is in spiral galaxies ; * the scatter in the estimation of star formation rates in various bands is similar to that of spiral galaxies and is mainly due to age effects ; * the combination of the extinction uncorrected Halpha line with mid-infrared yields a good estimation of the actual star formation rate ; * an important part of star formation, which can be as high as 85%, takes place in the intergalactic medium showing that in a young universe, in which this type of system is much more common than in the nearby universe, star formation from collisional debris can be an important factor of enrichment of

  10. Sparse Image Format

    2007-04-12

    The Sparse Image Format (SIF) is a file format for storing spare raster images. It works by breaking an image down into tiles. Space is savid by only storing non-uniform tiles, i.e. tiles with at least two different pixel values. If a tile is completely uniform, its common pixel value is stored instead of the complete tile raster. The software is a library in the C language used for manipulating files in SIF format. Itmore » supports large files (> 2GB) and is designed to build in Windows and Linux environments.« less

  11. Sparse Image Format

    SciTech Connect

    Eads, Damian Ryan

    2007-04-12

    The Sparse Image Format (SIF) is a file format for storing spare raster images. It works by breaking an image down into tiles. Space is savid by only storing non-uniform tiles, i.e. tiles with at least two different pixel values. If a tile is completely uniform, its common pixel value is stored instead of the complete tile raster. The software is a library in the C language used for manipulating files in SIF format. It supports large files (> 2GB) and is designed to build in Windows and Linux environments.

  12. Plant Formate Dehydrogenase

    SciTech Connect

    John Markwell

    2005-01-10

    The research in this study identified formate dehydrogenase, an enzyme that plays a metabolic role on the periphery of one-carbon metabolism, has an unusual localization in Arabidopsis thaliana and that the enzyme has an unusual kinetic plasticity. These properties make it possible that this enzyme could be engineered to attempt to engineer plants with an improved photosynthetic efficiency. We have produced transgenic Arabidopsis and tobacco plants with increased expression of the formate dehydrogenase enzyme to initiate further studies.

  13. Display formats manual

    NASA Technical Reports Server (NTRS)

    Runnels, R. L.

    1973-01-01

    The standards and procedures for the generation of operational display formats to be used in the Mission Control Center (MCC) display control system are presented. The required effort, forms, and fundamentals for the design, specifications, and production of display formats are identified. The principles of display design and system constraints controlling the creation of optimum operational displays for mission control are explained. The basic two types of MCC display systems for presenting information are described.

  14. Autonomous Formation Flight

    NASA Technical Reports Server (NTRS)

    Schkolnik, Gerard S.; Cobleigh, Brent

    2004-01-01

    NASA's Strategic Plan for the Aerospace Technology Enterprise includes ambitious objectives focused on affordable air travel, reduced emissions, and expanded aviation-system capacity. NASA Dryden Flight Research Center, in cooperation with NASA Ames Research Center, the Boeing Company, and the University of California, Los Angeles, has embarked on an autonomous-formation-flight project that promises to make significant strides towards these goals. For millions of years, birds have taken advantage of the aerodynamic benefit of flying in formation. The traditional "V" formation flown by many species of birds (including gulls, pelicans, and geese) enables each of the trailing birds to fly in the upwash flow field that exists just outboard of the bird immediately ahead in the formation. The result for each trailing bird is a decrease in induced drag and thus a reduction in the energy needed to maintain a given speed. Hence, for migratory birds, formation flight extends the range of the system of birds over the range of birds flying solo. The Autonomous Formation Flight (AFF) Project is seeking to extend this symbiotic relationship to aircraft.

  15. Positronium Formation in Muscle

    PubMed Central

    Gustafson, D. R.

    1970-01-01

    Positronium formation in muscle at +4°C and -4°C was examined by the measurement of the angular correlation of positron annihilation radiation. Since the positronium formation rate in ice is considerably higher than it is in water, there should be a comparable increase in the positronium formation rate in muscle tissue if recent speculation that cellular water is ordered in a semicrystalline icelike state is correct. Comparison of the angular correlation from muscle at +4°C with that from water at +4°C shows no enhancement of the positronium formation rate. Frozen muscle at -4°C shows an enhancement of the positronium formation rate of approximately half that found in ice at -4°C, indicating that most cellular water undergoes a normal water-ice transition when frozen. It is concluded therefore that cell water in muscle is not ordered in a hexagonal icelike structure. While the results are consistent with the hypothesis that cell water is in the liquid state, the hypothesis that cell water is ordered in an undetermined close packed structure which transforms to the hexagonal ice structure at or near 0°C cannot be ruled out. PMID:5436881

  16. Revised nomenclature and stratigraphic relationships of the Fredericksburg Complex and Quantico Formation of the Virginia Piedmont

    USGS Publications Warehouse

    Pavlides, Louis

    1980-01-01

    The Fredericksburg Complex, in part a migmatitic terrane in northeast Virginia, is subdivided on the basis of lithology, as well as aeromagnetic and aeroradiometric data, into two metamorphic suites. These suites are separated by the northeast-trending Spotsylvania lineament, a rectilinear geophysical feature that is probably the trace of an old fault zone. East of the lineament, the Po River Metamorphic Suite, of Proterozoic Z and (or) early Paleozoic age, consists dominantly of biotite gneiss, generally augen gneiss, and lesser amounts of hornblende gneiss and mica schist. West of the Spotsylvania lineament is the Ta River Metamorphic Suite, composed mostly of amphibolite and amphibole gneiss. However, to the southwest, along its strike belt, the Ta River contains abundant biotite gneiss and mica schist. Both the Ta River and Po River contain abundant foliated granitoid and pegmatoid bodies as concordant tabular masses and as crosscutting dikes; these rocks are considered part of the Ta River and Po River Metamorphic Suites. The amphibolitic Holly Corner Gneiss is interpreted to be a western allochthonous equivalent of the Ta River. Both the Ta River and Holly Corner are considered to be coeval, eastern, distal facies of the Lower Cambrian(?) Chopawamsic Formation. The Paleozoic Falls Run Granite Gneiss intrudes the Ta River Metamorphic Suite and the Holly Corner Gneiss; locally the Falls Run is interpreted to have been transported westward with the Holly Corner after intrusion. The Quantico Formation, in the core of the Quantico-Columbia synclinorium, rests with angular unconformity along its northwest and southeast limbs, respectively, on the Chopawamsic Formation and the Ta River Metamorphic Suite. The Quantico Formation is assigned the same Late Ordovician age and similar stratigraphic position as the Arvonia Slate of the Arvonia syncline. The youngest rocks of the area are the granitoid and pegmatoid bodies of the Falmouth Intrusive Suite. They consist of

  17. Planet Formation and Habitability

    NASA Astrophysics Data System (ADS)

    alibert, yann

    2016-04-01

    Extrasolar planetary systems show an extreme diversity in mass and orbital architecture, and, very likely, in habitability. Explaining this diversity is one of the key challenges for theoretical models and requires understanding the formation, composition and evolution of planetary systems from the stage of the protoplanetary disk up to the full mature planetary system. I will review in this contribution the different models of planet formation and how they can be related to planetary habitability. In a first part, I will review the main planetary system formation models, and how, from these models, the composition of planets can be predicted. In a second part, I will link the results of these early phases of planetary systems, to the potential planetary habitability. Finally, I will show how it is possible, from transit observations, to put constraints on the water content of extrasolar planets.

  18. Gaussian entanglement of formation

    SciTech Connect

    Wolf, M.M.; Giedke, G.; Krueger, O.; Werner, R. F.; Cirac, J.I.

    2004-05-01

    We introduce a Gaussian version of the entanglement of formation adapted to bipartite Gaussian states by considering decompositions into pure Gaussian states only. We show that this quantity is an entanglement monotone under Gaussian operations and provide a simplified computation for states of arbitrary many modes. For the case of one mode per site the remaining variational problem can be solved analytically. If the considered state is in addition symmetric with respect to interchanging the two modes, we prove additivity of the considered entanglement measure. Moreover, in this case and considering only a single copy, our entanglement measure coincides with the true entanglement of formation.

  19. Isolating Triggered Star Formation

    SciTech Connect

    Barton, Elizabeth J.; Arnold, Jacob A.; Zentner, Andrew R.; Bullock, James S.; Wechsler, Risa H.; /KIPAC, Menlo Park /SLAC

    2007-09-12

    Galaxy pairs provide a potentially powerful means of studying triggered star formation from galaxy interactions. We use a large cosmological N-body simulation coupled with a well-tested semi-analytic substructure model to demonstrate that the majority of galaxies in close pairs reside within cluster or group-size halos and therefore represent a biased population, poorly suited for direct comparison to 'field' galaxies. Thus, the frequent observation that some types of galaxies in pairs have redder colors than 'field' galaxies is primarily a selection effect. We use our simulations to devise a means to select galaxy pairs that are isolated in their dark matter halos with respect to other massive subhalos (N= 2 halos) and to select a control sample of isolated galaxies (N= 1 halos) for comparison. We then apply these selection criteria to a volume-limited subset of the 2dF Galaxy Redshift Survey with M{sub B,j} {le} -19 and obtain the first clean measure of the typical fraction of galaxies affected by triggered star formation and the average elevation in the star formation rate. We find that 24% (30.5 %) of these L* and sub-L* galaxies in isolated 50 (30) h{sup -1} kpc pairs exhibit star formation that is boosted by a factor of {approx}> 5 above their average past value, while only 10% of isolated galaxies in the control sample show this level of enhancement. Thus, 14% (20 %) of the galaxies in these close pairs show clear triggered star formation. Our orbit models suggest that 12% (16%) of 50 (30) h{sup -1} kpc close pairs that are isolated according to our definition have had a close ({le} 30 h{sup -1} kpc) pass within the last Gyr. Thus, the data are broadly consistent with a scenario in which most or all close passes of isolated pairs result in triggered star formation. The isolation criteria we develop provide a means to constrain star formation and feedback prescriptions in hydrodynamic simulations and a very general method of understanding the importance of

  20. Technobabble: File Formats.

    ERIC Educational Resources Information Center

    Wilson, Bradley

    1999-01-01

    Considers the confusion of over 20 different kinds of graphics programs. Briefly distinguishes between some of the more popular graphics formats (Photoshop, TIFF, JPEG, GIF, PICT, and EPS), and describes the benefits and disadvantages of each in the context of journalism education. (SC)

  1. Formation of planetesimals

    NASA Technical Reports Server (NTRS)

    Weidenschilling, Stuart J.

    1991-01-01

    Formation of planetesimals is discussed. The following subject areas are covered: (1) nebular structure; (2) aerodynamics of the solid bodies in the nebula; (3) problems with gravitational instability; (4) particle growth by coagulation; properties of fractal aggregates; and (5) coagulation and settling of fractal aggregates.

  2. Carrascolendas: A Formative Evaluation.

    ERIC Educational Resources Information Center

    Laosa, Luis M.

    A formative research project sought to test viewer reactions to two pilot programs of the Carrascolendas series. A total of 360 Puerto Rican-American, Cuban-American, Mexican-American, and Anglo-American children in grades 1, 2, and 3 were observed as they watched the programs. Results indicated that there was high eye contact during the…

  3. Formation of Freirian Facilitators.

    ERIC Educational Resources Information Center

    Noble, Phyllis

    This paper is written for people who are already familiar with the philosophy and methodology of Paulo Freire's liberatory education and are interested in creating a formation program for adult education facilitators using his ideas. The author describes the paper as "a collection of thoughts, of things to consider," when organizing such a…

  4. Formation in the Classroom

    ERIC Educational Resources Information Center

    Glennon, Fred; Jacobsen, Douglas; Jacobsen, Rhonda Hustedt; Thatamanil, John J.; Porterfield, Amanda; Moore, Mary Elizabeth

    2011-01-01

    What is the relationship between the academic knowledge of the guild and the formation of students in the classroom? This Forum gathers four essays originally presented at a Special Topics Session at the 2009 conference of the American Academy of Religion (Atlanta, Georgia), with a brief introductory essay by Fred Glennon explaining the genesis of…

  5. Concept Formation and Abstraction.

    ERIC Educational Resources Information Center

    Lunzer, Eric A.

    1979-01-01

    This paper examines the nature of concepts and conceptual processes and the manner of their formation. It argues that a process of successive abstraction and systematization is central to the evolution of conceptual structures. Classificatory processes are discussed and three levels of abstraction outlined. (Author/SJL)

  6. Common file formats.

    PubMed

    Leonard, Shonda A; Littlejohn, Timothy G; Baxevanis, Andreas D

    2007-01-01

    This appendix discusses a few of the file formats frequently encountered in bioinformatics. Specifically, it reviews the rules for generating FASTA files and provides guidance for interpreting NCBI descriptor lines, commonly found in FASTA files. In addition, it reviews the construction of GenBank, Phylip, MSF and Nexus files. PMID:18428774

  7. Kepler Planet Formation

    NASA Technical Reports Server (NTRS)

    Lissauer, Jack J.

    2015-01-01

    Kepler has vastly increased our knowledge of planets and planetary systems located close to stars. The new data shows surprising results for planetary abundances, planetary spacings and the distribution of planets on a mass-radius diagram. The implications of these results for theories of planet formation will be discussed.

  8. Generic file format

    NASA Astrophysics Data System (ADS)

    Felgate, Nick

    2002-11-01

    The Generic File Format (GFF) is a file format developed within the UK ASW community for the interchange and storage of underwater sonar data. Originally developed for the interchange of time-series data between analysis systems, it has been extended to provide for storage of processed acoustic data (e.g., power and DEMON spectrum, lofargram grey-scale), nonacoustic data (e.g., own-ship dynamics, sensor configuration) and event data (e.g., tracker output, sonar intercepts). The format employs the chunk concept, as used in the WAV and AIFF file formats, to provide extendability (including local variants) while providing a measure of backward compatability. However, the basic concept has been adapted to allow for the mixing in the one file of multiple channels of different sample-rates and data-types through the inclusion of a data frame concept and multiple data blocks. Chunk cross-referencing has been employed to ensure data consistency. A provision is made in the header of the file to store details of the sensor and processing for the data (e.g., the number of hydrophones, beam direction, FFT size) so that an analysis system does not need to know about the sensor or other system from which the data originated.

  9. The Formation of Trihalomethanes.

    ERIC Educational Resources Information Center

    Trussell, R. Rhodes; Umphres, Mark D.

    1978-01-01

    Reviewed are a number of factors important in the formation of trihalomethanes (THM) including the nature of aquatic humus and the influences of preozonation, bromide, pH, and chlorine. A brief investigation is also conducted into the kinetics of the THM reaction. Several major research needs are represented. (CS)

  10. Pattern formation today

    PubMed Central

    Chuong, Cheng-Ming; Richardson, Michael K.

    2010-01-01

    Patterns are orders embedded in randomness. They may appear as spatial arrangements or temporal series, and the elements may appear identical or with variations. Patterns exist in the physical world as well as in living systems. In the biological world, patterns can range from simple to complex, forming the basic building blocks of life. The process which generates this ordering in the biological world was termed pattern formation. Since Wolpert promoted this concept four decades ago, scientists from molecular biology, developmental biology, stem cell biology, tissue engineering, theoretical modeling and other disciplines have made remarkable progress towards understanding its mechanisms. It is time to review and re-integrate our understanding. Here, we explore the origin of pattern formation, how the genetic code is translated into biological form, and how complex phenotypes are selected over evolutionary time. We present four topics: Principles, Evolution, Development, and Stem Cells and Regeneration. We have interviewed several leaders in the field to gain insight into how their research and the field of pattern formation have shaped each other. We have learned that both molecular process and physico-chemical principles are important for biological pattern formation. New understanding will emerge through integration of the analytical approach of molecular-genetic manipulation and the systemic approach of model simulation. We regret that we could not include every major investigator in the field, but hope that this Special Issue of the Int. J. Dev. Biol. represents a sample of our knowledge of pattern formation today, which will help to stimulate more research on this fundamental process. PMID:19557673

  11. Medusae Fossae Formation

    NASA Technical Reports Server (NTRS)

    2002-01-01

    (Released 10 April 2002) The Science This THEMIS visible image was acquired near 7o S, 172o W (188o E) and shows a remarkable martian geologic deposit known as the Medusae Fossae Formation. This Formation, seen here as the raised plateau in the upper two-thirds of the image, is a soft, easily eroded deposit that extends for nearly 1,000 km along the equator of Mars. In this region the deposit has been heavily eroded by the wind to produce a series of linear ridges called yardangs. These parallel ridges point in direction of the prevailing winds that carved them, and demonstrate the power of martian winds to sculpt the dry landscape of Mars. The Medusae Fossae Formation has been completely stripped from the surface in the lower third of the image, revealing a harder layer below that is more resistant to wind erosion. The easily eroded nature of the Medusae Fossae Formation suggests that it is composed of weakly cemented particles, and was most likely formed by the deposition of wind-blown dust or volcanic ash. Several ancient craters that were once completely buried by this deposit are being exposed, or exhumed, as the overlying Medusae Formation is removed. Very few impact craters are visible on this Formation, indicating that the surface seen today is relatively young, and that the processes of erosion are likely to be actively occurring. The Story Medusa of Greek mythology fame, the name-giver to this region, had snaky locks of hair that could turn a person to stone. Wild and unruly, this monster of the underworld could certainly wreak havoc on the world of the human imagination. As scary as she was, Medusa would have no advantage over the fierce, masterful winds blowing across Mars, which once carved the streaky, terrain at the top of this image. Wild and whipping, these winds have slowly eroded away the 'topsoil,' revealing ancient craters and other surface features they once covered. The loosely cemented particles of this 'topsoil' are likely made up of dust

  12. Formation of tectonic peperites from alkaline magmas intruded into wet sediments in the Beiya area, western Yunnan, China

    NASA Astrophysics Data System (ADS)

    Xu, Xing-Wang; Cai, Xin-Ping; Zhong, Jia-You; Song, Bao-Chang; Peters, Stephen G.

    2007-08-01

    Tertiary (3.78 Ma to 3.65 Ma) biotite-K-feldspar porphyritic bodies intrude Tertiary, poorly consolidated lacustrine sedimentary rocks in the Beiya mineral district in southwestern China. The intrusives are characterized by a microcrystalline and vitreous-cryptocrystalline groundmass, by replacement of some tabular K-feldspar phenocrysts with microcrystalline chlorite and calcite, and by Fe-rich rings surrounding biotite phenocrysts. Peculiar structures, such as contemporary contact faults and slickensides, ductile shear zones and flow folds, foliation and lineations, tension fractures, and banded and boudin peperites, are developed along the contact zones of the intrusives. These features are related to the forceful intrusion of the alkaline magmas into the wet Tertiary sediments. The partially consolidated magmas were deformed and flattened by continued forceful magma intrusion that produced boudinaged and banded peperites. These peperites characterized by containing oriented deformation fabrics are classified as tectonic peperites as a new type of peperite, and formation of these tectonic peperites was related to fracturing of magmas caused by forceful intrusion and shear deformation and to contemporary migration and injection of fluidized sediments along fractures that dismembered the porphyritic magma. Emplacement of the magma into the wet sediments in the Beiya area is interpreted to be related to a large pressure difference rather than to the buoyancy force.

  13. Variations in fluvial style in Westwater Canyon member, Morrison Formation (Jurassic), southern San Juan basin, Colorado plateau

    SciTech Connect

    Miall, A.D.; Turner-Peterson, C.E.

    1988-02-01

    The large-scale architecture of fluvial strata within the Westwater Canyon Member of the Morrison Formation consists mainly of a series of tabular sheets of sandstone 5-15 m thick and hundreds of meters wide separated by thin fine-grained units. These sandstone sheets are commonly flat bedded; however, lateral accretion surfaces and channels 10-20 m deep and up to at least 250 m wide are also present. Where studied in detail, the sheets comprise a complex of elements and bounding surfaces unlike any previously described from ancient fluvial deposits. Lateral accretion deposits, typical indicators of moderate to high-sinuosity channels, coexist in the same outcrop with downstream-accreted foreset macroform deposits now thought to be typical of the sand flats of low-sinuosity, multiple-channel rivers. Broad deep channels with gently to steeply dipping margins have been mapped by carefully tracing major bounding surfaces in several of the outcrops. Fining-upward sequences are rare in the project area, contrary to earlier descriptions. Analogies with the depositional architecture of the large Indian rivers, such as the Ganga and Brahmaputra, still seem reasonable, although convincing evidence now exists for aridity and for major stage fluctuations, which differs from those modern rivers and previous interpretations.

  14. Formation of tectonic peperites from alkaline magmas intruded into wet sediments in the Beiya area, western Yunnan, China

    USGS Publications Warehouse

    Xu, X.-W.; Cai, X.-P.; Zhong, J.-Y.; Song, B.-C.; Peters, S.G.

    2007-01-01

    Tertiary (3.78 Ma to 3.65 Ma) biotite-K-feldspar porphyritic bodies intrude Tertiary, poorly consolidated lacustrine sedimentary rocks in the Beiya mineral district in southwestern China. The intrusives are characterized by a microcrystalline and vitreous-cryptocrystalline groundmass, by replacement of some tabular K-feldspar phenocrysts with microcrystalline chlorite and calcite, and by Fe-rich rings surrounding biotite phenocrysts. Peculiar structures, such as contemporary contact faults and slickensides, ductile shear zones and flow folds, foliation and lineations, tension fractures, and banded and boudin peperites, are developed along the contact zones of the intrusives. These features are related to the forceful intrusion of the alkaline magmas into the wet Tertiary sediments. The partially consolidated magmas were deformed and flattened by continued forceful magma intrusion that produced boudinaged and banded peperites. These peperites characterized by containing oriented deformation fabrics are classified as tectonic peperites as a new type of peperite, and formation of these tectonic peperites was related to fracturing of magmas caused by forceful intrusion and shear deformation and to contemporary migration and injection of fluidized sediments along fractures that dismembered the porphyritic magma. Emplacement of the magma into the wet sediments in the Beiya area is interpreted to be related to a large pressure difference rather than to the buoyancy force. ?? 2007 Elsevier Ltd. All rights reserved.

  15. Cosmological structure formation

    NASA Technical Reports Server (NTRS)

    Schramm, David N.

    1991-01-01

    A summary of the current forefront problem of physical cosmology, the formation of structures (galaxies, clusters, great walls, etc.) in the universe is presented. Solutions require two key ingredients: (1) matter; and (2) seeds. Regarding the matter, it now seems clear that both baryonic and non-baryonic matter are required. Whether the non-baryonic matter is hot or cold depends on the choice of seeds. Regarding the seeds, both density fluctuations and topological defects are discussed. The combination of isotropy of the microwave background and the recent observations indicating more power on large scales have severly constrained, if not eliminated, Gaussian fluctuations with equal power on all scales, regardless of the eventual resolution of both the matter and seed questions. It is important to note that all current structure formation ideas require new physics beyond SU(3) x SU(2) x U(1).

  16. Emptiness Formation Probability

    NASA Astrophysics Data System (ADS)

    Crawford, Nicholas; Ng, Stephen; Starr, Shannon

    2016-08-01

    We present rigorous upper and lower bounds on the emptiness formation probability for the ground state of a spin-1/2 Heisenberg XXZ quantum spin system. For a d-dimensional system we find a rate of decay of the order {exp(-c L^{d+1})} where L is the sidelength of the box in which we ask for the emptiness formation event to occur. In the {d=1} case this confirms previous predictions made in the integrable systems community, though our bounds do not achieve the precision predicted by Bethe ansatz calculations. On the other hand, our bounds in the case {d ≥ 2} are new. The main tools we use are reflection positivity and a rigorous path integral expansion, which is a variation on those previously introduced by Toth, Aizenman-Nachtergaele and Ueltschi.

  17. Tetrahedron Formation Control

    NASA Technical Reports Server (NTRS)

    Petruzzo, Charles; Guzman, Jose

    2004-01-01

    This paper considers the preliminary development of a general optimization procedure for tetrahedron formation control. The maneuvers are assumed to be impulsive and a multi-stage optimization method is employed. The stages include (1) targeting to a fixed tetrahedron location and orientation, and (2) rotating and translating the tetrahedron. The number of impulsive maneuvers can also be varied. As the impulse locations and times change, new arcs are computed using a differential corrections scheme that varies the impulse magnitudes and directions. The result is a continuous trajectory with velocity discontinuities. The velocity discontinuities are then used to formulate the cost function. Direct optimization techniques are employed. The procedure is applied to the NASA Goddard Magnetospheric Multi-Scale (MMS) mission to compute preliminary formation control fuel requirements.

  18. Prominence Formation Processes

    NASA Astrophysics Data System (ADS)

    Welsch, B. T.; DeVore, C. R.; Antiochos, S. K.

    2005-01-01

    Martens and Zwaan (ApJ v. 558 872) have proposed a prominence/ filament formation model in which differential rotation drives reconnection between two initially unconnected active regions to form helical field lines that support mass and are held down by overlying field. Using an MHD solver with adaptive refinement we simulated this process by imposing a shear flow meant to mimic differential rotation on two bipolar flux distributions meant to mimic distinct active regions. In some runs the flux systems are initially potential while in others they have been twisted by footpoint rotation to inject helicity prior to imposing the shear flow. The resulting structures are studied to understand the role of helicity in the formation of prominence-like structures.

  19. Formation of bacterial nanocells

    NASA Astrophysics Data System (ADS)

    Vainshtein, Mikhail; Kudryashova, Ekaterina; Suzina, Natalia; Ariskina, Elena; Voronkov, Vadim

    1998-07-01

    Existence of nanobacteria received increasing attention both in environmental microbiology/geomicro-biology and in medical microbiology. In order to study a production of nanoforms by typical bacterial cells. Effects of different physical factors were investigated. Treatment of bacterial cultures with microwave radiation, or culturing in field of electric current resulted in formation a few types of nanocells. The number and type of nanoforms were determined with type and dose of the treatment. The produced nanoforms were: i) globules, ii) clusters of the globules--probably produced by liaison, iii) nanocells coated with membrane. The viability of the globules is an object opened for doubts. The nanocells discovered multiplication and growth on solidified nutrient media. The authors suggest that formation of nanocells is a common response of bacteria to stress-actions produced by different agents.

  20. Galaxy Formation and Evolution

    NASA Astrophysics Data System (ADS)

    Nagamine, Kentaro; Reddy, Naveen; Daddi, Emanuele; Sargent, Mark T.

    2016-07-01

    In this chapter, we discuss the current status of observational and computational studies on galaxy formation and evolution. In particular, a joint analysis of star-formation rates (SFRs), stellar masses, and metallicities of galaxies throughout cosmic time can shed light on the processes by which galaxies build up their stellar mass and enrich the environment with heavy elements. Comparison of such observations and the results of numerical simulations can give us insights on the physical importance of various feedback effects by supernovae and active galactic nuclei. In Sect. 1, we first discuss the primary methods used to deduce the SFRs, stellar masses, and (primarily) gas-phase metallicities in high-redshift galaxies. Then, we show how these quantities are related to each other and evolve with time. In Sect. 2, we further examine the distribution of SFRs in galaxies following the `Main Sequence' paradigm. We show how the so-called `starbursts' display higher specific SFRs and SF efficiencies by an order of magnitude. We use this to devise a simple description of the evolution of the star-forming galaxy population since z ˜3 that can successfully reproduce some of the observed statistics in the infrared (IR) wavelength. We also discuss the properties of molecular gas. In Sect. 3, we highlight some of the recent studies of high-redshift galaxy formation using cosmological hydrodynamic simulations. We discuss the physical properties of simulated galaxies such as luminosity function and escape fraction of ionizing photons, which are important statistics for reionization of the Universe. In particular the escape fraction of ionizing photons has large uncertainties, and studying gamma-ray bursts (which is the main topic of this conference) can also set observational constraints on this uncertain physical parameter as well as cosmic star formation rate density.

  1. Simulations of antihydrogen formation

    SciTech Connect

    Robicheaux, F.

    2004-08-01

    The results of simulations of antihydrogen formation in a Penning trap are reported. The antihydrogen atoms are formed by three-body capture. We find that the arrested nature of the three-body capture in the trap greatly reduces the expected binding energy of the antihydrogen. Typically, the formed antihydrogen has larger velocity along the magnetic field than across the field and a binding energy below k{sub B}T.

  2. Formate-assisted pyrolysis

    DOEpatents

    DeSisto, William Joseph; Wheeler, Marshall Clayton; van Heiningen, Adriaan R. P.

    2015-03-17

    The present invention provides, among other thing, methods for creating significantly deoxygenated bio-oils form biomass including the steps of providing a feedstock, associating the feedstock with an alkali formate to form a treated feedstock, dewatering the treated feedstock, heating the dewatered treated feedstock to form a vapor product, and condensing the vapor product to form a pyrolysis oil, wherein the pyrolysis oil contains less than 30% oxygen by weight.

  3. Mesospheric cloud formations

    NASA Technical Reports Server (NTRS)

    Forbes, J. M.

    1980-01-01

    Formation of mesospheric clouds as a result of deposition of large amounts of H2O by the heavy lift launch vehicle (HLLV) of the solar power satellite system is discussed. The conditions which must be met in order to form and maintain clouds near the mesopause are described. The frequency and magnitude of H2O injections from the HLLV rocket exhaust are considered.

  4. Hail Formation in Florida

    NASA Astrophysics Data System (ADS)

    Stanley, Matthew

    Hail poses a substantial threat to life and property in the state of Florida. These losses could be minimized through better understanding of the relationships between atmospheric variables that impact hail formation in Florida. Improving hail forecasting in Florida requires analyzing a number of meteorological parameters and synoptic data related to hail formation. NOAA archive data was retrieved to create a database that was used to categorize text files of hail days. The text files were entered into the National Oceanic and Atmospheric Administration Earth System Research Laboratory website to create National Centers for Environmental Prediction/National Center for Atmospheric Research Reanalysis maps of atmospheric variables for Florida hail days as well as days leading to the hail event. These data were then analyzed to determine the relationship between variables that affect hail formation, in general, across different regions and seasons in Florida using Statistical Product and Service Solutions. The reasoning for the differing factors affecting hail formation between regions, seasons and hail sizes were discussed, as well as forecasting suggestions relating to region and month in Florida. The study found that the majority of all hail that occurs in Florida is during the wet season. A low Lifted Index, high Precipitable Water and lower than average Sea Level Pressure, in most cases, is present during hail days in Florida. Furthermore, results show that Vector Wind magnitude increases as hail size increases. Additionally, several atmospheric variables useful to studying hail events, such as Lifted Index, Precipitable Water, Sea Level Pressure, Vector Wind and Temperature have significant correlations with each other depending on the region and season being observed. Strong correlations between low Lifted Index, high Precipitable Water values and the occurrence of hail events are discussed, as well as the relationship between temperature anomalies at various

  5. Tetrahedron Formation Control

    NASA Technical Reports Server (NTRS)

    Guzman, Jose J.

    2003-01-01

    Spacecraft flying in tetrahedron formations are excellent instrument platforms for electromagnetic and plasma studies. A minimum of four spacecraft - to establish a volume - is required to study some of the key regions of a planetary magnetic field. The usefulness of the measurements recorded is strongly affected by the tetrahedron orbital evolution. This paper considers the preliminary development of a general optimization procedure for tetrahedron formation control. The maneuvers are assumed to be impulsive and a multi-stage optimization method is employed. The stages include targeting to a fixed tetrahedron orientation, rotating and translating the tetrahedron and/or varying the initial and final times. The number of impulsive maneuvers citn also be varied. As the impulse locations and times change, new arcs are computed using a differential corrections scheme that varies the impulse magnitudes and directions. The result is a continuous trajectory with velocity discontinuities. The velocity discontinuities are then used to formulate the cost function. Direct optimization techniques are employed. The procedure is applied to the Magnetospheric Multiscale Mission (MMS) to compute preliminary formation control fuel requirements.

  6. Terrestrial planet formation.

    PubMed

    Righter, K; O'Brien, D P

    2011-11-29

    Advances in our understanding of terrestrial planet formation have come from a multidisciplinary approach. Studies of the ages and compositions of primitive meteorites with compositions similar to the Sun have helped to constrain the nature of the building blocks of planets. This information helps to guide numerical models for the three stages of planet formation from dust to planetesimals (~10(6) y), followed by planetesimals to embryos (lunar to Mars-sized objects; few 10(6) y), and finally embryos to planets (10(7)-10(8) y). Defining the role of turbulence in the early nebula is a key to understanding the growth of solids larger than meter size. The initiation of runaway growth of embryos from planetesimals ultimately leads to the growth of large terrestrial planets via large impacts. Dynamical models can produce inner Solar System configurations that closely resemble our Solar System, especially when the orbital effects of large planets (Jupiter and Saturn) and damping mechanisms, such as gas drag, are included. Experimental studies of terrestrial planet interiors provide additional constraints on the conditions of differentiation and, therefore, origin. A more complete understanding of terrestrial planet formation might be possible via a combination of chemical and physical modeling, as well as obtaining samples and new geophysical data from other planets (Venus, Mars, or Mercury) and asteroids.

  7. Terrestrial planet formation.

    PubMed

    Righter, K; O'Brien, D P

    2011-11-29

    Advances in our understanding of terrestrial planet formation have come from a multidisciplinary approach. Studies of the ages and compositions of primitive meteorites with compositions similar to the Sun have helped to constrain the nature of the building blocks of planets. This information helps to guide numerical models for the three stages of planet formation from dust to planetesimals (~10(6) y), followed by planetesimals to embryos (lunar to Mars-sized objects; few 10(6) y), and finally embryos to planets (10(7)-10(8) y). Defining the role of turbulence in the early nebula is a key to understanding the growth of solids larger than meter size. The initiation of runaway growth of embryos from planetesimals ultimately leads to the growth of large terrestrial planets via large impacts. Dynamical models can produce inner Solar System configurations that closely resemble our Solar System, especially when the orbital effects of large planets (Jupiter and Saturn) and damping mechanisms, such as gas drag, are included. Experimental studies of terrestrial planet interiors provide additional constraints on the conditions of differentiation and, therefore, origin. A more complete understanding of terrestrial planet formation might be possible via a combination of chemical and physical modeling, as well as obtaining samples and new geophysical data from other planets (Venus, Mars, or Mercury) and asteroids. PMID:21709256

  8. Mars brine formation experiment

    NASA Astrophysics Data System (ADS)

    Moore, Jeffrey M.; Bullock, Mark A.; Stoker, Carol R.

    1993-09-01

    Evaporites, particularly carbonates, nitrates, and sulfates, may be major sinks of volatiles scavenged from the martian atmosphere. Mars is thought to have once had a denser, warmer atmosphere that permitted the presence of liquid surface water. The conversion of atmospheric CO2 into carbonate is hypothesized to have degraded the martian climate to its present state of a generally subfreezing, desiccated desert. The rate for such a conversion under martian conditions is poorly known, so the time scale of climate degradation by this process cannot be easily evaluated. If some models are correct, carbonate formation may have been fast at geological time scales. The experiments of Booth and Kieffer also imply fast (106 - 107 yr) removal of the missing CO2 inventory, estimated to be 1 - 5 bar, by means of carbonate formation. The timing of formation of many of the fluvial features observed on Mars is, in large part, dependent on when and how fast the atmosphere changed. A knowledge of the rate at which carbonates and nitrates formed is also essential for assessing the probability that life, or its chemical precursors, could have developed on Mars. No previous experiments have quantitatively evaluated the rate of solution for a suite of mobile anions and cations from unaltered minerals and atmospheric gases into liquid water under Mars-like conditions. Such experiments are the focus of this task.

  9. Terrestrial planet formation

    PubMed Central

    Righter, K.; O’Brien, D. P.

    2011-01-01

    Advances in our understanding of terrestrial planet formation have come from a multidisciplinary approach. Studies of the ages and compositions of primitive meteorites with compositions similar to the Sun have helped to constrain the nature of the building blocks of planets. This information helps to guide numerical models for the three stages of planet formation from dust to planetesimals (∼106 y), followed by planetesimals to embryos (lunar to Mars-sized objects; few × 106 y), and finally embryos to planets (107–108 y). Defining the role of turbulence in the early nebula is a key to understanding the growth of solids larger than meter size. The initiation of runaway growth of embryos from planetesimals ultimately leads to the growth of large terrestrial planets via large impacts. Dynamical models can produce inner Solar System configurations that closely resemble our Solar System, especially when the orbital effects of large planets (Jupiter and Saturn) and damping mechanisms, such as gas drag, are included. Experimental studies of terrestrial planet interiors provide additional constraints on the conditions of differentiation and, therefore, origin. A more complete understanding of terrestrial planet formation might be possible via a combination of chemical and physical modeling, as well as obtaining samples and new geophysical data from other planets (Venus, Mars, or Mercury) and asteroids. PMID:21709256

  10. Shallow lacustrine system of the Permian Pedra de Fogo Formation, Western Gondwana, Parnaíba Basin, Brazil

    NASA Astrophysics Data System (ADS)

    Araújo, Raphael Neto; Nogueira, Afonso César Rodrigues; Bandeira, José; Angélica, Rômulo Simões

    2016-04-01

    The Permian Period of the Parnaíba Basin, northern Brazil, represented here by deposits from the Pedra de Fogo Formation, records important events that occurred in Western Gondwana near its boundary with the Mesozoic Era. The analysis of outcrop based facies from the Permian Pedra de Fogo Formation, which is 100 m thick, carried out along the eastern and western borders of the Parnaiba Basin, allowed the identification of eleven sedimentary facies, which were grouped into three distinct facies associations (FA), representative of a shallow lacustrine system associated with mudflats and ephemeral rivers. Bioturbation, desiccation cracks, silcretes and various siliceous concretions characterize the Pedra de Fogo deposits. The FA1 mudflat deposits occur predominantly at the base of the Pedra de Fogo Formation and consist of laminated claystone/mudstone, mudcrack-bearing sandstones/mudstones and sandstones exhibiting cross-lamination, massive and megaripple bedding. Popcorn-like silicified nodules and casts indicate evaporite deposits. Other common features are silica concretions, silicified tepees and silcretes. FA2 represents nearshore deposits and consists of fine-grained sandstones with evenly parallel lamination, climbing ripple cross-lamination, massive and megaripple bedding and mudstone/siltstone showing evenly parallel lamination. FA3 refers to wadi/inundite deposits, generally organized as fining-upward cycles of metric size, composed of conglomerates and medium-grained pebbly sandstones showing massive bedding and cross-stratification, as well as claystone/siltstone showing evenly parallel to undulate lamination. Scour-and-fill features are isolated in predominantly tabular deposits composed of mudstones interbedded with fine to medium-grained sandstones showing planar to slightly undulate lamination. Silicified plant remains previously classified as belonging to the Psaronius genus found in the uppermost levels of the Pedra de Fogo Formation, near the

  11. Field-based description of rhyolite lava flows of the Calico Hills Formation, Nevada National Security Site, Nevada

    USGS Publications Warehouse

    Sweetkind, Donald S.; Bova, Shiera C.

    2015-01-01

    In the area south of the Rainier Mesa caldera, surface and subsurface geologic data are combined to interpret the overall thickness of the Calico Hills Formation and the proportion of lava flow lithology across the study area. The formation is at least 500 meters (m) thick and contains the greatest proportion of rhyolite lava flow to the northeast of Yucca Mountain in the lower part of Fortymile Canyon. The formation thins to the south and southwest where it is between 50 and 200 m thick beneath Yucca Mountain and contains no rhyolite lavas. Geologic mapping and field-based correlation of individual lava flows allow for the interpretation of the thickness and extent of specific flows and the location of their source areas. The most extensive flows have widths from 2 to 3 kilometers (km) and lengths of at least 5–6 km. Lava flow thickness varies from 150 to 250 m above interpreted source vents to between 30 and 80 m in more distal locations. Rhyolite lavas have length-to-height ratios of 10:1 or greater and, in one instance, a length-to-width ratio of 2:1 or greater, implying a tongue-shaped geometry instead of circular domes or tabular bodies. Although geologic mapping did not identify any physical feature that could be positively identified as a vent, lava flow thickness and the size of clasts in subjacent pyroclastic deposits suggest that primary vent areas for at least some of the flows in the study area are on the east side of Fortymile Canyon, to the northeast of Yucca Mountain.

  12. Isostatic gravity map and principal facts for 694 gravity stations in Yellowstone National Park and vicinity, Wyoming, Montana, and Idaho

    USGS Publications Warehouse

    Carle, S.F.; Glen, J.M.; Langenheim, V.E.; Smith, R.B.; Oliver, H.W.

    1990-01-01

    The report presents the principal facts for gravity stations compiled for Yellowstone National Park and vicinity. The gravity data were compiled from three sources: Defense Mapping Agency, University of Utah, and U.S. Geological Survey. Part A of the report is a paper copy describing how the compilation was done and presenting the data in tabular format as well as a map; part B is a 5-1/4 inch floppy diskette containing only the data files in ASCII format. Requirements for part B: IBM PC or compatible, DOS v. 2.0 or higher. Files contained on this diskette: DOD.ISO -- File containing the principal facts of the 514 gravity stations obtained from the Defense Mapping Agency. The data are in Plouff format* (see file PFTAB.TEX). UTAH.ISO -- File containing the principal facts of 153 gravity stations obtained from the University of Utah. Data are in Plouff format. USGS.ISO -- File containing the principal facts of 27 gravity stations collected by the U.S. Geological Survey in July 1987. Data are in Plouff format. PFTAB.TXT -- File containing explanation of principal fact format. ACC.TXT -- File containing explanation of accuracy codes.

  13. Model of kimberlite formation

    NASA Astrophysics Data System (ADS)

    Kostrovitsky, Sergey; Fiveyskaya, Lyudmila

    2013-04-01

    The critical goals in recognizing the nature of kimberlites are to find out: (1) the primary composition of melt of these rocks and (2) the principal processes of evolution of primary composition of kimberlites while ascending from mantle depth towards earth surface. Suppose, that the primary composition of kimberlite melt-fluid was in fact the composition of asthenosphere melt geochemically being close to alkaline-basalt (Hi-µ) saturated with high CO2. The genetic relation of kimberlites with basaltoids is indicated by a spatial and temporal affinity of their formation (Carlson et al, 2006; Lehmann et al, 2010; Tappe et al, 2012), similarity of the pattern of incompatible elements distribution, presence of megacryst minerals in alkaline basaltoids, Pyr-Alm garnet included, and finally, model calculation of parent melt composition for low-Cr megacryst minerals; it showed this composition to be typical for the alkaline basaltoid (Jones, 1980). At the asthenosphere level there was differentiation of basaltoid melt-fluid which was responsible for formation of its different parts with varying melt to fluid ratio and possibly varying content of alkalis (K2O). The outbreak of asthenosphere substance through lithosphere mantle proceeded by different scenarios: (a) With a noticeable dominance of fluid component kimberlites were formed by the capture and contamination of high-Mg, high-Cr rocks of lithosphere mantle that caused formation of high-Mg kimberlites. That corresponds to model of Russell (2012). (b) With a considerable proportion of melt phase depending on saturation in fluid there formed magnesium-ferriferous and ferriferous-titaniferous petrochemical types of kimberlites. There is no doubt that in formation of these kimberlite types the contamination of lithosphere material was the case, at the much lower level than in formation of high-Mg kimberlites. This model logically explains steady differences of petrochemistry of kimberlites making up clusters of

  14. Formation of giant planets

    NASA Astrophysics Data System (ADS)

    Magni, G.; Coradini, A.

    2003-04-01

    In this presentation we address the problem of the formation of giant planets and their regular satellites. We study in particular the problem of formation of the Jupiter System comparing the results of the model with the present characteristics of the system, in order to identify what are those better represented by our approach. In fact here, using a 3-D hydro-dynamical code, we study the modalities of gas accretion onto a solid core, believed to be the seed from which Jupiter started. To do that we have modelled three main regions: the central planet, a turbulent accretion disk surrounding it and an extended region from which the gas is collected. In the extended region we treat the gas as a frictionless fluid. Our main goal is to identify what are the characteristics of the planet during its growth and the physical parameters affecting its growth at the expenses of the nebular gas present in the feeding zone. Moreover we want to understand what are the thermodynamical parameters characterizing the gas captured by the planet and swirling around it. Finally, we check if a disk can be formed in prograde rotation around the planet and if this disk can survive the final phases of the planet formation. Due to the interaction between the accreting planet and the disk it has been necessary to develop a complete model of the Jupiter’s structure. In fact the radiation emitted by the growing planet heats up the surrounding gas. In turn the planet’s thermodynamic structure depend on the mass accretion rate onto it. When the accretion is rapid, shock waves in the gas are formed close to the planet. This region cannot be safely treated by a numerical code; for this reason we have developed a semi-analytically model of a a turbulent accretion disk to be considered as transition between the planet and the surrounding disk.

  15. What initiated planetesimal formation?

    NASA Technical Reports Server (NTRS)

    Cuzzi, J. N.; Dobrovolskis, A. R.; Hogan, R. C.

    1994-01-01

    The physical structure of primitive (chondritic) meteorites, even after some geological processing and modification, is thought by most to contain clues as to the first stage of accretion of solid matter into objects that might be called planetesimals. However, theoretical understanding of the processes responsible for this important stage is shaky. We note what we believe are fundamental obstacles for the Goldreich-Ward version of rapid and direct planetesimal formation via gravitational instability in a settled particle layer, and describe an alternative scenario which might lead from grainy nebula gas to primitive planetesimals in a way that has intriguing connections to the meteorite evidence.

  16. Modeling river delta formation.

    PubMed

    Seybold, Hansjörg; Andrade, José S; Herrmann, Hans J

    2007-10-23

    A model to simulate the time evolution of river delta formation process is presented. It is based on the continuity equation for water and sediment flow and a phenomenological sedimentation/erosion law. Different delta types are reproduced by using different parameters and erosion rules. The structures of the calculated patterns are analyzed in space and time and compared with real data patterns. Furthermore, our model is capable of simulating the rich dynamics related to the switching of the mouth of the river delta. The simulation results are then compared with geological records for the Mississippi River. PMID:17940031

  17. Ultrarelativistic black hole formation.

    PubMed

    East, William E; Pretorius, Frans

    2013-03-01

    We study the head-on collision of fluid particles well within the kinetic energy dominated regime (γ = 8 to 12) by numerically solving the Einstein-hydrodynamic equations. We find that the threshold for black hole formation is lower (by a factor of a few) than simple hoop conjecture estimates, and, moreover, near this threshold two distinct apparent horizons first form postcollision and then merge. We argue that this can be understood in terms of a gravitational focusing effect. The gravitational radiation reaches luminosities of 0.014 c(5)/G, carrying 16 ± 2% of the total energy.

  18. Adiabatic Halo Formation

    SciTech Connect

    Bazzani, A.; Turchetti, G.; Benedetti, C.; Rambaldi, S.; Servizi, G.

    2005-06-08

    In a high intensity circular accelerator the synchrotron dynamics introduces a slow modulation in the betatronic tune due to the space-charge tune depression. When the transverse motion is non-linear due to the presence of multipolar effects, resonance islands move in the phase space and change their amplitude. This effect introduces the trapping and detrapping phenomenon and a slow diffusion in the phase space. We apply the neo-adiabatic theory to describe this diffusion mechanism that can contribute to halo formation.

  19. Flexible formation configuration for terrain following flight: Formation keeping constraints

    NASA Astrophysics Data System (ADS)

    Latyshev, Simon

    This work suggests a control method for the terrain-following formation motion of a group of communicating autonomous agents. The presented approach centers on defining a suitable set of constraints for formation keeping task that shall be fulfilled while agents are negotiating an unknown terrain toward the predefined goal location. It allows agents to maintain a general geometric formation shape, while allowing each individual formation member freedom of maneuver, required for terrain collision free motion. Formation structure is defined with the use of virtual leader. Formation keeping constraints are defined with plane surfaces, specified relative to position and navigation vector of the virtual leader. Formation navigation and guidance constraints are defined using navigation vectors of formation members and the virtual leader. Alternative designs for the constraints derived with parabolic, cone, and cylindrical surfaces are considered. Formation control is derived using the Udwadia-Kalaba equation, following corresponding approach to the development of control methods for constraint based dynamical systems, including leader-follower systems defined using geometric constraints. Approach to terrain following motion requiring agents to stay within bounds of cylindrical corridor volumes built around their respective navigation vectors is assumed. Individual formation primitives and multi-level, hierarchical, formation structures are considered. Simulations, based on three degrees of freedom nonlinear model of an agent, performed using Mathematica and specifically developed combined Maya-Mathematica modeling and simulation system, demonstrate that a flexible terrain following formation motion is achieved with the presented sets of constraints.

  20. Sedimentology and lithofacies of the Eocene Skookumchuk Formation in the Centralia coal mine, southwest Washington

    SciTech Connect

    Flores, R.M.; Johnson, S.Y.

    1995-04-01

    The late middle to late Eocene Skookumchuck Formation is well exposed in highwalls of the Centralia mine, southwest Washington. Three coal zones and intervening sandstone-rich successions occur in a 220-m-thick interval that extends from below the Smith to above the Tono No. 1 coal beds. The Smith-Big Dirty, Lower-Upper Thompson, and Tono No.`s. 1-2 coal zones contain coal beds that range from 0.5 to 15 m thick. The coal beds are interbedded with coarsening-upward units of mudstone, siltstone, and sandstone that are burrowed, flaser-and lenticular-bedded, mud-draped in their lower part, and rippled, wavy bedded, and tabular crossbedded (with reactivation surfaces) in their upper part. These coarsening-upward units are commonly overlain erosionally by fining-upward beds of trough-crossbedded, rippled, burrowed, and rooted sandstones. Coal formed in low-lying peat mires above mean high tide levels. Two discrete facies occur in the sandstone-rich successions between the coal zones. The first facies consists of very fine to coarse grained sandstones that have sharply defined bases and tops and are heavily bioturbated, horizontally bedded, trough crossbedded, hummocky bedded, and rippled. The second facies of the sandstone-rich successions consists of sandstone, siltstone, and mudstone beds with common ripple lamination, lenticular and flaser bedding, trough crossbedding, biotrubation, bivalve fossils, and root marks. Upward thinning of coal beds is consistent with deposition during a major transgression. These coals formed in mires of the tidally influenced coastal plain in the Centralia mine area, in contrast to coals elsewhere in Washington that accumulated in mires of the fluvial- and distributary-channel-influenced coastal plain. The Northcraft volcanic center to the east probably deflected fluvial drainages of the coastal plain to the north and south.

  1. Late Diagenetic Cements in the Murray Formation, Gale Crater, Mars: Implications for Postdepositional Fluid Flow

    NASA Astrophysics Data System (ADS)

    Kah, L. C.; Kronyak, R. E.; Van Beek, J.; Nachon, M.; Mangold, N.; Thompson, L. M.; Wiens, R. C.; Grotzinger, J. P.; Schieber, J.

    2015-12-01

    The Murray formation in its type section at Pahrump Hills, consists of approximately 14 meters of recessive-weathering mudstone interbedded with decimeter-scale cross-bedded sandstone in the upper portions of the exposed section. Mudstone textures vary from massive, to poorly laminated, to well laminated. Unusual 3-dimensional crystal clusters and dendrites occur in the lowermost part of the section and are erosionally resistant with respect to the host rock. Crystal clusters consist of elongate lathes that occur within individual blocks of the fractured substrate. Individual lathes show tabular morphologies with a pseudo-rectangular cross-section and the three dimensional morphology of the crystal clusters cross-cut host rock lamination with little or no deformation. Dendritic structures are typically larger and show predominantly planar growth aligned with bedding planes. Individual lathes within the dendrites are elongate and pseudo-rectangular in cross-section. Unlike crystal clusters, dendritic morphologies appear to nucleate at bedrock fractures and near mineralized veins. Here we show evidence that crystal clusters and dendrites are post-depositional, potentially burial diagenetic features. Association of features with through-going fractures suggests that fractures may have been a primary transport pathway for ions responsible for dendrite growth. Even where dendrites do not occur, enhanced cementation suggests that fluids permeated the rock matrix. We suggest that growth of clusters proceeded as inter-particle crystal growth, wherein mineral growth within inter-particle spaces resulted in cementation and porosity loss, with little further effect on the rock matrix. Crystal clusters and dendrites are most likely to form when mineral saturation states are highest, for instance with initial intrusion of fracture-borne fluids and mixing with ambient pore fluids, and thus emphasize the importance of fractures in ion transport during late diagenesis.

  2. Star Formation in Irregular Galaxies.

    ERIC Educational Resources Information Center

    Hunter, Deidre; Wolff, Sidney

    1985-01-01

    Examines mechanisms of how stars are formed in irregular galaxies. Formation in giant irregular galaxies, formation in dwarf irregular galaxies, and comparisons with larger star-forming regions found in spiral galaxies are considered separately. (JN)

  3. Standard exercise report format (SERF)

    SciTech Connect

    1995-12-31

    This talk summarizes the reasons for the development of draft SERF the Standard Exercise Report Format used for reporting the results of emergency preparedness exercises, and gives a summary of the format and rational behind it.

  4. Formats for Presenting Procedural Instruction

    ERIC Educational Resources Information Center

    Blaiwes, Arthur S.

    1974-01-01

    Thirty male college students performed a mock communication controller's task under three different instructional formats, short sentences, logical tree, and coding. It was concluded that format variations mainly influence the more difficult tasks. (Author/DE)

  5. Tooth formation - delayed or absent

    MedlinePlus

    Delayed or absent tooth formation; Teeth - delayed or absent formation ... The age at which a tooth comes in varies. Most infants get their first tooth between 6 and 9 months, but it may be earlier or later. ...

  6. Fullerene formation and annealing

    SciTech Connect

    Mintmire, J.W.

    1996-04-05

    Why does the highly symmetric carbon cluster C{sub 60} form in such profusion under the right conditions? This question was first asked in 1985, when Kroto suggested that the predominance of the C{sub 60} carbon clusters observed in the molecular beam experiments could be explained by the truncated icosahedral (or soccer ball) form. The name given to this cluster, buckminsterfullerene, led to the use of the term fullerenes for the family of hollow-cage carbon clusters made up of even numbers of triply coordinated carbons arranged with 12 pentagonal rings and an almost arbitrary number of hexagonal rings. More than a decade later, we still lack a completely satisfying understanding of the fundamental chemistry that takes place during fullerene formation. Most current models for fullerene formation require a facile mechanism for ring rearrangement in the fullerene structure, but the simplest proposed mechanisms are believed to have unrealistically high activation barriers. In recent research calculations have suggested that atomic carbon in the reaction mixture could act as a catalyst and allow substantially lower activation barriers for fullerene annealing. This article discusses the background for this research and other adjunct research. 14 refs.

  7. Bubble formation in microgravity

    NASA Technical Reports Server (NTRS)

    Antar, Basil N.

    1994-01-01

    Two KC-135 flight campaigns have been conducted to date which are specifically dedicated to study bubble formation in microgravity. The first flight was conducted during March 14-18, 1994, and the other during June 20-24, 1994. The results from the June 1994 flight have not been analyzed yet, while the results from the March flight have been partially analyzed. In the first flight three different experiments were performed, one with the specific aim at determining whether or not cavitation can take place during any of the fluid handling procedures adopted in the shuttle bioprocessing experiments. The other experiments were concerned with duplicating some of the procedures that resulted in bubble formation, namely the NCS filling procedure and the needle scratch of a solid surface. The results from this set of experiments suggest that cavitation did not take place during any of the fluid handling procedures. The results clearly indicate that almost all were generated as a result of the breakup of the gas/liquid interface. This was convincingly demonstrated in the scratch tests as well as in the liquid fill tests.

  8. Holocene key coral species in the Northwest Pacific: indicators of reef formation and reef ecosystem responses to global climate change and anthropogenic stresses in the near future

    NASA Astrophysics Data System (ADS)

    Hongo, Chuki

    2012-03-01

    The geological record of key coral species that contribute to reef formation and maintenance of reef ecosystems is important for understanding the ecosystem response to global-scale climate change and anthropogenic stresses in the near future. Future responses can be predicted from accumulated data on Holocene reef species identified in drillcore and from data on raised reef terraces. The present study analyzes a dataset based on 27 drillcores, raised reef terraces, and 134 radiocarbon and U-Th ages from reefs of the Northwest Pacific, with the aim of examining the role of key coral species in reef growth and maintenance for reef ecosystem during Holocene sea-level change. The results indicate a latitudinal change in key coral species: arborescent Acropora (Acropora intermedia and Acropora muricata) was the dominant reef builder at reef crests in the tropics, whereas Porites (Porites australiensis, Porites lutea, and Porites lobata) was the dominant contributor to reef growth in the subtropics between 10,000 and 7000 cal. years BP (when the rate of sea-level rise was 10 m/ka). Acropora digitifera, Acropora hyacinthus, Acropora robusta/A. abrotanoides, Isopora palifera, Favia stelligera, and Goniastrea retiformis from the corymbose and tabular Acropora facies were the main key coral species at reef crests between 7000 and 5000 cal. years BP (when the rate of sea-level rise was 5 m/ka) and during the following period of stable sea-level. Massive Porites (P. australiensis, P. lutea, and P. lobata) contributed to reef growth in shallow lagoons during the period of stable sea level. Key coral species from the corymbose and tabular Acropora facies have the potential to build reefs and maintain ecosystems in the near future under a global sea-level rise of 2-6 m/ka, as do key coral species from the arborescent Acropora facies and massive Porites facies, which show vigorous growth and are tolerant to relatively deep-water, low-energy environments. However, these species

  9. Method for measuring pollutant formation

    NASA Technical Reports Server (NTRS)

    Annen, Kurt (Inventor); Stickler, David B. (Inventor)

    2001-01-01

    Diagnostic methods for determining an instantaneous rate of pollutant formation in a combustion system are based on measurement of chemiluminescence intensity generated simultaneously with the formation of the pollutant. The chemiluminescent signal is generated by an analog reaction which occurs in parallel with a key step in the formation of a specific pollutant of interest. The connection between the analog reaction and the pollution reaction is such that the chemiluminescent signal indicates the local, instantaneous formation rate of the pollutant of interest.

  10. Formative Assessment: Simply, No Additives

    ERIC Educational Resources Information Center

    Roskos, Kathleen; Neuman, Susan B.

    2012-01-01

    Among the types of assessment the closest to daily reading instruction is formative assessment. In contrast to summative assessment, which occurs after instruction, formative assessment involves forming judgments frequently in the flow of instruction. Key features of formative assessment include identifying gaps between where students are and…

  11. Statins and bone formation.

    PubMed

    Garrett, I R; Gutierrez, G; Mundy, G R

    2001-05-01

    The main therapy needed most in the bone field is an anabolic agent for the treatment of osteoporosis. Current drugs on the market, which included bisphosphonates, calcitonin, estrogen and related compounds, vitamin D analogues trabecular microarchitecture. Therefore, it would be desirable to have a satisfactory and universally and iprifalvone, are essentially bone resorption inhibitors that mainly act to stabilize bone mass. Patients with established osteoporosis have lost more than 50% of their bone mass at critical sites in the skeleton, and more over have marked disruption of acceptable drug that would stimulate new bone formation and correct this disturbance of trabecular microarchitecture characteristic of established osteoporosis. Recently inhibitors of the enzyme 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase, which controls the first step in the biosynthesis of cholesterol, have been shown to stimulate bone formation in rodents both in vitro and in vivo. The effect is associated with an increased expression of the bone morphogenetic protein-2 (BMP-2) gene in bone cells. These statins drugs are widely used agents for lowering cholesterol and reducing heart attacks, however they are also known to elicit numerous pleiotropic effects including inhibition of proliferation and migration of smooth muscle cells, inhibition of tumor growth and anti-inflammatory activity. Some of these effects have been attributed to not only to the reduction of cholesterol synthesis by inhibition of the HMG-CoA reductase enzyme but also by the concurrent reduction in downstream metabolites of the mevalonate pathway such as mevalonate, farnesyl pyrophosphate and geranylgeranyl pyrophosphate. The findings that statins are capable of increasing bone formation and bone mass in rodents suggests a potential new action for the statins, which may be beneficial in patients with established osteoporosis where marked bone loss has occurred. Recent clinical data suggests that they

  12. Physics of amniote formation.

    PubMed

    Fleury, Vincent; Murukutla, Ameya Vaishnavi; Chevalier, Nicolas R; Gallois, Benjamin; Capellazzi-Resta, Marina; Picquet, Pierre; Peaucelle, Alexis

    2016-08-01

    We present a detailed study of the formation of the amniotic sac in the avian embryo, and a comparison with the crocodile amniotic sac. We show that the amniotic sac forms at a circular line of stiffness contrast, separating rings of cell domains. Cells align at this boundary, and this in turn orients and concentrates the tension forces. The tissue fold which forms the amniotic sac is locked exactly along this line due to the colocalization of the stiffness contrast and of the tensile force. In addition, the tensile force plays a regenerative role when the amniotic sac is cut. The fold forming the ventral side of the embryo displays the same characteristics. This work shows that amniote embryogenesis consists of a cascade of buckling events taking place at the boundaries between regions of differing mechanical properties. Hence, amniote embryogenesis relies on a simple and robust biomechanical scheme used repeatedly, and selected ancestrally.

  13. Physics of amniote formation.

    PubMed

    Fleury, Vincent; Murukutla, Ameya Vaishnavi; Chevalier, Nicolas R; Gallois, Benjamin; Capellazzi-Resta, Marina; Picquet, Pierre; Peaucelle, Alexis

    2016-08-01

    We present a detailed study of the formation of the amniotic sac in the avian embryo, and a comparison with the crocodile amniotic sac. We show that the amniotic sac forms at a circular line of stiffness contrast, separating rings of cell domains. Cells align at this boundary, and this in turn orients and concentrates the tension forces. The tissue fold which forms the amniotic sac is locked exactly along this line due to the colocalization of the stiffness contrast and of the tensile force. In addition, the tensile force plays a regenerative role when the amniotic sac is cut. The fold forming the ventral side of the embryo displays the same characteristics. This work shows that amniote embryogenesis consists of a cascade of buckling events taking place at the boundaries between regions of differing mechanical properties. Hence, amniote embryogenesis relies on a simple and robust biomechanical scheme used repeatedly, and selected ancestrally. PMID:27627351

  14. Mechanism of GEMS formation

    SciTech Connect

    Bradley, J P; Dai, Z R

    2004-03-10

    GEMS (glass with embedded metal and sulfides) in interplanetary dust particles (IDPs) were examined using 200 keV analytical transmission electron microscopy. The morphologies and crystallography of embedded relict grains reveal that GEMS are pseudomorphs formed by irradiation processing of crystals free-floating in space. Some GEMS retain a compositional and morphological ''memory'' of the crystal from which they formed. Pseudomorphism rules out condensation, annealing, flash heating, or shock melting as alternative mechanisms of GEMS formation. A significant and often dominant fraction of the atoms in GEMS were sputtered deposited from other grains. Therefore, a normal (solar) isotopic composition is not a reliable indicator of whether GEMS formed in the solar system or in presolar interstellar or circumstellar environments.

  15. Transitions in biofilm formation

    NASA Astrophysics Data System (ADS)

    Gordon, Vernita; Thatcher, Travis; Cooley, Benjamin

    2011-03-01

    Biofilms are multicellular, dynamic communities formed by interacting unicellular organisms bound to a surface. Forming a biofilm is a developmental process, characterized by sequential changes in gene expression and behavior as bacteria and yeast progress from discrete, free-swimming cells though stages that arrive at a mature biofilm. We are developing automated metrics to identify key transitions in early biofilm formation as cells attach to a surface, populate that surface, and adhere to each other to form early microcolonies. Our metrics use high-throughput tracking and analysis of microscopy movies to localize these transitions in space and time. Each of these transitions is associated with a loss of entropy in the bacterial system and, therefore, with biological activity that drives this loss of entropy. Better understanding of these transitions will allow automated determination of the strength and turn-on of attractive cell-surface and cell-cell interactions as biofilm development progresses.

  16. DUST FORMATION IN MACRONOVAE

    SciTech Connect

    Takami, Hajime; Ioka, Kunihito; Nozawa, Takaya E-mail: kunihito.ioka@kek.jp

    2014-07-01

    We examine dust formation in macronovae (as known as kilonovae), which are the bright ejecta of neutron star binary mergers and one of the leading sites of r-process nucleosynthesis. In light of information about the first macronova candidate associated with GRB 130603B, we find that dust grains of r-process elements have difficulty forming because of the low number density of the r-process atoms, while carbon or elements lighter than iron can condense into dust if they are abundant. Dust grains absorb emission from ejecta with an opacity even greater than that of the r-process elements, and re-emit photons at infrared wavelengths. Such dust emission can potentially account for macronovae without r-process nucleosynthesis as an alternative model. This dust scenario predicts a spectrum with fewer features than the r-process model and day-scale optical-to-ultraviolet emission.

  17. Group Formation in Economics

    NASA Astrophysics Data System (ADS)

    Demange, Gabrielle; Wooders, Myrna

    2005-01-01

    Broad and diverse ranges of activities are conducted within and by organized groups of individuals, including political, economic and social activities. These activities have recently become a subject of intense interest in economics and game theory. Some of the topics investigated in this collection are models of networks of power and privilege, trade networks, co-authorship networks, buyer-seller networks with differentiated products, and networks of medical innovation and the adaptation of new information. Other topics are social norms on punctuality, clubs and the provision of club goods and public goods, research and development and collusive alliances among corporations, and international alliances and trading agreements. While relatively recent, the literature on game theoretic studies of group formation in economics is already vast. This volume provides an introduction to this important literature on game-theoretic treatments of situations with networks, clubs, and coalitions, including some applications.

  18. Physics of amniote formation

    NASA Astrophysics Data System (ADS)

    Fleury, Vincent; Murukutla, Ameya Vaishnavi; Chevalier, Nicolas R.; Gallois, Benjamin; Capellazzi-Resta, Marina; Picquet, Pierre; Peaucelle, Alexis

    2016-08-01

    We present a detailed study of the formation of the amniotic sac in the avian embryo, and a comparison with the crocodile amniotic sac. We show that the amniotic sac forms at a circular line of stiffness contrast, separating rings of cell domains. Cells align at this boundary, and this in turn orients and concentrates the tension forces. The tissue fold which forms the amniotic sac is locked exactly along this line due to the colocalization of the stiffness contrast and of the tensile force. In addition, the tensile force plays a regenerative role when the amniotic sac is cut. The fold forming the ventral side of the embryo displays the same characteristics. This work shows that amniote embryogenesis consists of a cascade of buckling events taking place at the boundaries between regions of differing mechanical properties. Hence, amniote embryogenesis relies on a simple and robust biomechanical scheme used repeatedly, and selected ancestrally.

  19. Biofilm formation by enterococci.

    PubMed

    Mohamed, Jamal A; Huang, David B

    2007-12-01

    Enterococci are an important global cause of nosocomial infections, being increasingly associated with urinary tract infections, endocarditis, intra-abdominal and pelvic infections, catheter-related infections, surgical wound infections, and central nervous system infections. The two most common enterococci species are Enterococcus faecalis and Enterococcus faecium. Both are capable of producing biofilms, which consist of a population of cells attached irreversibly on various biotic and abiotic surfaces, encased in a hydrated matrix of exopolymeric substances. Many environmental and genetic factors are associated or have been proposed to be associated with the production of biofilm. This review discusses recent advances in knowledge about the biology and genetics of biofilm formation and the role of biofilms in enterococci pathogenesis.

  20. Recipes for planet formation

    NASA Astrophysics Data System (ADS)

    Meyer, Michael R.

    2009-11-01

    Anyone who has ever used baking soda instead of baking powder when trying to make a cake knows a simple truth: ingredients matter. The same is true for planet formation. Planets are made from the materials that coalesce in a rotating disk around young stars - essentially the "leftovers" from when the stars themselves formed through the gravitational collapse of rotating clouds of gas and dust. The planet-making disk should therefore initially have the same gas-to-dust ratio as the interstellar medium: about 100 to 1, by mass. Similarly, it seems logical that the elemental composition of the disk should match that of the star, reflecting the initial conditions at that particular spot in the galaxy.

  1. Medusae Fossae Formation

    NASA Technical Reports Server (NTRS)

    2002-01-01

    (Released 16 April 2002) The Science This THEMIS visible image was acquired near 11o N, 159o W (201o E) and shows examples of the remarkable variations that can be seen in the erosion of the Medusae Fossae Formation. This Formation is a soft, easily eroded deposit that extends for nearly 1,000 km along the equator of Mars. In this region, like many others throughout the Medusae Fossae Formation, the surface has been eroded by the wind into a series of linear ridges called yardangs. These ridges generally point in direction of the prevailing winds that carved them, and demonstrate the power of martian winds to erode the landscape of Mars. The easily eroded nature of the Medusae Fossae Formation suggests that it is composed of weakly cemented particles, and was most likely formed by the deposition of wind-blown dust or volcanic ash. Within this single image it is possible to see differing amounts of erosion and stripping of layers in the Medusae Fossae Formation. Near the bottom (southern) edge of the image a rock layer with a relatively smooth upper surface covers much of the image. Moving upwards (north) in the image this layer becomes more and more eroded. At first there are isolated regions where the smooth unit has been eroded to produce sets of parallel ridges and knobs. Further north these linear knobs increase in number, and only small, isolated patches of the smooth upper surface remain. Finally, at the top of the image, even the ridges have been removed, exposing the remarkably smooth top of hard, resistant layer below. This sequence of layers with differing hardness and resistance to erosion is common on Earth and on Mars, and suggests significant variations in the physical properties, composition, particle size, and/or cementation of these martian layers. As is common throughout the Medusae Fossae Formation, very few impact craters are visible, indicating that the surface exposed is relatively young, and that the process of erosion may be active today

  2. Medusae Fossae Formation

    NASA Technical Reports Server (NTRS)

    2002-01-01

    (Released 16 April 2002) The Science This THEMIS visible image was acquired near 11o N, 159o W (201o E) and shows examples of the remarkable variations that can be seen in the erosion of the Medusae Fossae Formation. This Formation is a soft, easily eroded deposit that extends for nearly 1,000 km along the equator of Mars. In this region, like many others throughout the Medusae Fossae Formation, the surface has been eroded by the wind into a series of linear ridges called yardangs. These ridges generally point in direction of the prevailing winds that carved them, and demonstrate the power of martian winds to erode the landscape of Mars. The easily eroded nature of the Medusae Fossae Formation suggests that it is composed of weakly cemented particles, and was most likely formed by the deposition of wind-blown dust or volcanic ash. Within this single image it is possible to see differing amounts of erosion and stripping of layers in the Medusae Fossae Formation. Near the bottom (southern) edge of the image a rock layer with a relatively smooth upper surface covers much of the image. Moving upwards (north) in the image this layer becomes more and more eroded. At first there are isolated regions where the smooth unit has been eroded to produce sets of parallel ridges and knobs. Further north these linear knobs increase in number, and only small, isolated patches of the smooth upper surface remain. Finally, at the top of the image, even the ridges have been removed, exposing the remarkably smooth top of hard, resistant layer below. This sequence of layers with differing hardness and resistance to erosion is common on Earth and on Mars, and suggests significant variations in the physical properties, composition, particle size, and/or cementation of these martian layers. As is common throughout the Medusae Fossae Formation, very few impact craters are visible, indicating that the surface exposed is relatively young, and that the process of erosion may be active today

  3. Gas formation. Formation temperatures of thermogenic and biogenic methane.

    PubMed

    Stolper, D A; Lawson, M; Davis, C L; Ferreira, A A; Santos Neto, E V; Ellis, G S; Lewan, M D; Martini, A M; Tang, Y; Schoell, M; Sessions, A L; Eiler, J M

    2014-06-27

    Methane is an important greenhouse gas and energy resource generated dominantly by methanogens at low temperatures and through the breakdown of organic molecules at high temperatures. However, methane-formation temperatures in nature are often poorly constrained. We measured formation temperatures of thermogenic and biogenic methane using a "clumped isotope" technique. Thermogenic gases yield formation temperatures between 157° and 221°C, within the nominal gas window, and biogenic gases yield formation temperatures consistent with their comparatively lower-temperature formational environments (<50°C). In systems where gases have migrated and other proxies for gas-generation temperature yield ambiguous results, methane clumped-isotope temperatures distinguish among and allow for independent tests of possible gas-formation models. PMID:24970083

  4. Acromioclavicular joint cyst formation.

    PubMed

    Hiller, Andrew D; Miller, Joshua D; Zeller, John L

    2010-03-01

    Acromioclavicular joint (ACJ) cysts are an uncommon and unusual sequela associated with shoulder pathophysiology. The majority of literature on ACJ cysts consists of individual case reports with no definitive literature review currently available. In addition to a comprehensive literature review, four clinical cases are presented in this report. First described by Craig (1984), a total of 41 cases have been previously reported in the literature. Of these cases, five occurred with the rotator cuff musculature intact. The remaining 36 cases of ACJ cysts occurred in patients with a complete tear/avulsion of the rotator cuff. Previous attempts at compiling a complete record of all reported cases have combined several distinct conditions into a single category. This article presents two distinct etiologies for the pathogenesis of ACJ cyst formation. In the presence of an intact rotator cuff, a Type 1 cyst can form superficially and be limited to the ACJ. Following a massive or traumatic tear of the rotator cuff, mechanical instability of the humeral head can cause a deterioration of the inferior acromioclavicular capsule (cuff tear arthropathy) and an overproduction of synovial fluid. Overtime, a "geyser" of fluid can form between the glenohumeral and the ACJ, forming a Type 2 cyst. This differentiation and categorization is essential for appropriate classification and treatment.

  5. Nuclear ``pasta'' formation

    NASA Astrophysics Data System (ADS)

    Schneider, A. S.; Horowitz, C. J.; Hughto, J.; Berry, D. K.

    2013-12-01

    The formation of complex nonuniform phases of nuclear matter, known as nuclear pasta, is studied with molecular dynamics (MD) simulations containing 51200 nucleons. A phenomenological nuclear interaction is used that reproduces the saturation binding energy and density of nuclear matter. Systems are prepared at an initial density of 0.10fm-3 and then the density is decreased by expanding the simulation volume at different rates to densities of 0.01fm-3 or less. An originally uniform system of nuclear matter is observed to form spherical bubbles (“swiss cheese”), hollow tubes, flat plates (“lasagna”), thin rods (“spaghetti”) and, finally, nearly spherical nuclei with decreasing density. We explicitly observe nucleation mechanisms, with decreasing density, for these different pasta phase transitions. Topological quantities known as Minkowski functionals are obtained to characterize the pasta shapes. Different pasta shapes are observed depending on the expansion rate. This indicates nonequilibrium effects. We use this to determine the best ways to obtain lower energy states of the pasta system from MD simulations and to place constraints on the equilibration time of the system.

  6. Bubble formation in microgravity

    NASA Technical Reports Server (NTRS)

    Antar, Basil N.

    1996-01-01

    An extensive experimental program was initiated for the purpose of understanding the mechanisms leading to bubble generation during fluid handling procedures in a microgravity environment. Several key fluid handling procedures typical for PCG experiments were identified for analysis in that program. Experiments were designed to specifically understand how such procedures can lead to bubble formation. The experiments were then conducted aboard the NASA KC-135 aircraft which is capable of simulating a low gravity environment by executing a parabolic flight attitude. However, such a flight attitude can only provide a low gravity environment of approximately 10-2go for a maximum period of 30 seconds. Thus all of the tests conducted for these experiments were designed to last no longer than 20 seconds. Several experiments were designed to simulate some of the more relevant fluid handling procedures during protein crystal growth experiments. These include submerged liquid jet cavitation, filling of a cubical vessel, submerged surface scratch, attached drop growth, liquid jet impingement, and geysering experiments. To date, four separate KC-135 flight campaigns were undertaken specifically for performing these experiments. However, different experiments were performed on different flights.

  7. Formation of "bound

    NASA Astrophysics Data System (ADS)

    Nowak, K.; Kästner, M.; Miltner, A.

    2009-04-01

    During degradation of organic pollutants in soil, metabolites, microbial biomass, CO2and "bound" residues ("non-extractable" residues in soil organic matter) are formed. Enhanced transformation of these contaminants into "bound" residues has been proposed as an alternative remediation method for polluted soils. However, this kind of residues may pose a potential risk for the environment due to their chemical structure and possible remobilization under different conditions. Therefore particular attention is given actually to "bound" residues. Part of these non-extractable residues may be "biogenic," because microorganisms use the carbon from the pollutant to form their biomass components (fatty acids, amino acids, amino sugars), which subsequently may be incorporated into soil organic matter. Furthermore, the CO2 originating from mineralization of xenobiotics, can be re-assimilated by microorganisms and also incorporated into "biogenic residue". The hazard posed by "bound" residues may be overestimated because they are "biogenic" (contain microbial fatty acids and amino acids). The knowledge about the pathways of "biogenic residue" formation is necessary for a proper assessment of the fate of tested pollutants and their turnover in the soil environment. Moreover, these data are needed to establish the realistic degradation rates of the contaminants in soil. The main objectives of this study are: to quantify the extent of "biogenic residue" (fatty acids, amino acids, amino sugars) formation during the degradation of a model pollutant (2,4-dichlorophenoxyacetic acid = 2,4-D) and during CO2 assimilation by microorganisms and to evaluate which components are mainly incorporated into "bound" residues. To investigate the extent of "biogenic residue" formation in soil during the degradation of 2,4-D, experiments with either 14C-U-ring and 13C6-2,4-D or carboxyl-14C 2,4-D were performed. The incubation experiments were performed according to OECD test guideline 307, in the

  8. Prominence formation and oscillations

    NASA Astrophysics Data System (ADS)

    Chen, P. F.

    Prominences, or filaments, are a striking phenomenon in the solar atmosphere. Besides their own rich features and dynamics, they are related to many other activities, such as solar flares and coronal mass ejections (CMEs). In the past several years we have been investigating the prominence formation, oscillations, and eruptions through both data analysis and radiative hydrodynamic and magnetohydrodynamic (MHD) simulations. This paper reviews our progress on these topics, which includes: (1) With updated radiative cooling function, the coronal condensation becomes a little faster than previous work; (2) Once a seed condensation is formed, it can grow via siphon flow spontaneously even if the evaporation stops; (3) A scaling law was obtained to relate the length of the prominence thread to various parameters, indicating that higher prominences tend to have shorter threads, which is consistent with the fact that threads are long in active region prominences and short in quiescent prominences; (4) It was proposed that long-time prominence oscillations out of phase might serve as a precursor for prominence eruptions and CMEs; (5) An ensemble of oscillating prominence threads may explain the counter-streaming motion.

  9. Acromioclavicular joint cyst formation.

    PubMed

    Hiller, Andrew D; Miller, Joshua D; Zeller, John L

    2010-03-01

    Acromioclavicular joint (ACJ) cysts are an uncommon and unusual sequela associated with shoulder pathophysiology. The majority of literature on ACJ cysts consists of individual case reports with no definitive literature review currently available. In addition to a comprehensive literature review, four clinical cases are presented in this report. First described by Craig (1984), a total of 41 cases have been previously reported in the literature. Of these cases, five occurred with the rotator cuff musculature intact. The remaining 36 cases of ACJ cysts occurred in patients with a complete tear/avulsion of the rotator cuff. Previous attempts at compiling a complete record of all reported cases have combined several distinct conditions into a single category. This article presents two distinct etiologies for the pathogenesis of ACJ cyst formation. In the presence of an intact rotator cuff, a Type 1 cyst can form superficially and be limited to the ACJ. Following a massive or traumatic tear of the rotator cuff, mechanical instability of the humeral head can cause a deterioration of the inferior acromioclavicular capsule (cuff tear arthropathy) and an overproduction of synovial fluid. Overtime, a "geyser" of fluid can form between the glenohumeral and the ACJ, forming a Type 2 cyst. This differentiation and categorization is essential for appropriate classification and treatment. PMID:20069645

  10. Bead lightning formation

    SciTech Connect

    Ludwig, G.O.; Saba, M.M.F.

    2005-09-15

    Formation of beaded structures in triggered lightning discharges is considered in the framework of both magnetohydrodynamic (MHD) and hydrodynamic instabilities. It is shown that the space periodicity of the structures can be explained in terms of the kink and sausage type instabilities in a cylindrical discharge with anomalous viscosity. In particular, the fast growth rate of the hydrodynamic Rayleigh-Taylor instability, which is driven by the backflow of air into the channel of the decaying return stroke, dominates the initial evolution of perturbations during the decay of the return current. This instability is responsible for a significant enhancement of the anomalous viscosity above the classical level. Eventually, the damping introduced at the current channel edge by the high level of anomalous viscous stresses defines the final length scale of bead lightning. Later, during the continuing current stage of the lightning flash, the MHD pinch instability persists, although with a much smaller growth rate that can be enhanced in a M-component event. The combined effect of these instabilities may explain various aspects of bead lightning.

  11. The formation of dew

    NASA Astrophysics Data System (ADS)

    Beysens, D.

    Dew is the condensation into liquid droplets of water vapor on a substrate. The presence of a substrate is the origin of the peculiarities and richness of the phenomenon. We review the aspects related to heterogeneous nucleation and subsequent growth of water droplets. A key point is the drop interaction through drop fusion or coalescence, which leads to scaling in the growth and gives universality to the process. The effects of substrate heterogeneity and gravity effects are also considered. Coalescence events lead to temporal and spatio-temporal fluctuations in the substrate coverage, drop configuration, etc., which give rise to a very peculiar dynamics. When the substrate is a liquid or a liquid crystal, the drop pattern can exhibit special spatial orders, such as crystalline, hexatic phases and fractal contours. And condensation on a solid substrate near its melting point can make the drop jump. The applications of monitoring dew formation are manyfold. Examples can be found in nanoelectronics and optics (vapor deposition and thin films), medicine (sterilization process), agriculture (green houses). We here discuss in greater details the production of clean water by "atmospheric wells".

  12. Large Format Radiographic Imaging

    SciTech Connect

    J. S. Rohrer; Lacey Stewart; M. D. Wilke; N. S. King; S. A Baker; Wilfred Lewis

    1999-08-01

    Radiographic imaging continues to be a key diagnostic in many areas at Los Alamos National Laboratory (LANL). Radiographic recording systems have taken on many form, from high repetition-rate, gated systems to film recording and storage phosphors. Some systems are designed for synchronization to an accelerator while others may be single shot or may record a frame sequence in a dynamic radiography experiment. While film recording remains a reliable standby in the radiographic community, there is growing interest in investigating electronic recording for many applications. The advantages of real time access to remote data acquisition are highly attractive. Cooled CCD camera systems are capable of providing greater sensitivity with improved signal-to-noise ratio. This paper begins with a review of performance characteristics of the Bechtel Nevada large format imaging system, a gated system capable of viewing scintillators up to 300 mm in diameter. We then examine configuration alternatives in lens coupled and fiber optically coupled electro-optical recording systems. Areas of investigation include tradeoffs between fiber optic and lens coupling, methods of image magnification, and spectral matching from scintillator to CCD camera. Key performance features discussed include field of view, resolution, sensitivity, dynamic range, and system noise characteristics.

  13. Beach-cusp formation

    USGS Publications Warehouse

    Sallenger, A.H., Jr.

    1979-01-01

    Field experiments on beach-cusp formation were undertaken to document how the cuspate form develops and to test the edge-wave hypothesis on the uniform spacing of cusps. These involved observations of cusps forming from an initially plane foreshore. The cuspate form was observed to be a product of swash modification of an intertidal beach ridge as follows. A ridge, cut by a series of channels quasi-equally spaced along its length, was deposited onto the lower foreshore. The ridge migrated shoreward with flood tide, while the longshore positions of the channels remained fixed. On ebb tide, changes in swash circulation over the ridge allowed the upwash to flow shoreward through the channels and the channel mouths were eroded progressively wider until adjacent mouths met, effecting a cuspate shape. Measured spacings of cusps, ranging in size from less than 1 m to more than 12 m, agree well with computed spacings due to either zero-mode subharmonic or zero-mode synchronous edge waves. Edge-wave-induced longshore variations in run up will cause water ponded behind a ridge to converge at points of low swash and flow seaward as relatively narrow currents eroding channels spaced at one edge-wave wavelength for synchronous edge waves or one half wavelength for subharmonic edge waves. The channels are subsequently modified into cusp troughs as described above.

  14. The KEA image file format

    NASA Astrophysics Data System (ADS)

    Bunting, Peter; Gillingham, Sam

    2013-08-01

    There are a large number of image formats already in use within the remote sensing community but currently there is no format that provides the features of: compression, support for large file sizes, ground control points, raster attribute tables and inbuilt image pyramids. Therefore, a new image format, named KEA, after the New Zealand bird, has been proposed. The KEA format provides a full implementation of the GDAL data model and is implemented within a HDF5 file. A software library with a GDAL driver have been freely provided to the community allowing use through any GDAL based software. The new format has comparable performance with existing formats while producing smaller file sizes and is already within active use for a number of projects within Landcare Research, New Zealand, and the wider community.

  15. Gaining Insight into Star Formation: Resolved Star Formation Laws

    NASA Astrophysics Data System (ADS)

    Liebst, Kelley; Scowen, Paul A.

    2014-06-01

    Until recently astronomers have used star formation laws to measure the star formation rate and star formation efficiency of galaxies only on global scales because of the poor resolution of available data. What I am now capable of producing is a spatially resolved star formation law that can provide direct insight into the physical processes that govern star formation and assess the short-term nature of bursts of star formation and the longer-term nature of larger-scale events that can dictate the global distribution of stars and the ultimate fate of a galaxy as a whole. I am using exquisite narrowband optical data from a variety of sources, including the Hubble Space Telescope, and Kitt Peak National Observatory, etc., in conjunction with infrared data from the Spitzer Infrared Nearby Galaxy Survey and the Spitzer Local Volume Legacy survey, neutral gas data from The HI Nearby Galaxy Survey, and molecular gas data from the Berkeley-Illinois-Maryland Association Survey of Nearby Galaxies, to provide star formation rates and star formation efficiencies on previously inaccessible small spatial scales across a suite of galaxies that represent a range of star formation environments and scales. My sample includes 18 spiral galaxies ranging from 2.1 to 15.1 Mpc in distance and offers a large range of morphological types (i.e. a large range of star formation environments). I am using these data to test different models of star formation modes under a variety of physical conditions and relate the variations I observe to the known local physical conditions and the associated star formation histories for each locale within each galaxy.This is the heart of the matter - that the nature and evolution of the local physical environment intimately influences how stars can form, how quickly and how massive those stars are allowed to form, and as a result how they shape the local conditions for subsequent star formation. It is this tracking of the stellar ecology that is vital for

  16. Chapter 21: Programmatic Interfaces - STILTS

    NASA Astrophysics Data System (ADS)

    Fitzpatrick, M. J.

    STILTS is the Starlink Tables Infrastructure Library Tool Set developed by Mark Taylor of the former Starlink Project. STILTS is a command-line tool (see the NVOSS_HOME/bin/stilts command) providing access to the same functionality driving the TOPCAT application and can be run using either the STILTS-specific jar file, or the more general TOPCAT jar file (both are available in the NVOSS_HOME/java/lib directory and are included in the default software environment classpath). The heart of both STILTS and TOPCAT is the STIL Java library. STIL is designed to efficiently handle the input, output and processing of very large tabular datasets and the STILTS task interface makes it an ideal tool for the scripting environment. Multiple formats are supported (including FITS Binary Tables, VOTable, CSV, SQL databases and ASCII, amongst others) and while some tools will generically handle all supported formats, others are specific to the VOTable format. Converting a VOTable to a more script-friendly format is the first thing most users will encounter, but there are many other useful tools as well.

  17. BACTERIOPHAGE FORMATION WITHOUT BACTERIAL GROWTH

    PubMed Central

    Price, Winston H.

    1947-01-01

    1. Iodoacetate, fluoride, and azide have been found to prevent the formation of phage and to inhibit the synthesis of ATP by Staphylococcus muscae. It is suggested that energy-rich phosphate is needed for the synthesis of phage. 2. Gramicidin prevented the formation of phage. 3. No differences were found between normal bacteria and phage-infected bacteria in the inorganic phosphate, adenosinetriphosphate, ribonucleic acid, and desoxyribonucleic acid content of the cells. 4. The mechanism of phage formation is discussed. PMID:18896936

  18. Binary stars - Formation by fragmentation

    NASA Technical Reports Server (NTRS)

    Boss, Alan P.

    1988-01-01

    Theories of binary star formation by capture, separate nuclei, fission and fragmentation are compared, assessing the success of theoretical attempts to explain the observed properties of main-sequence binary stars. The theory of formation by fragmentation is examined, discussing the prospects for checking the theory against observations of binary premain-sequence stars. It is concluded that formation by fragmentation is successful at explaining many of the key properties of main-sequence binary stars.

  19. Medusae Fossae Formation

    NASA Technical Reports Server (NTRS)

    1998-01-01

    An exotic terrain of wind-eroded ridges and residual smooth surfaces are seen in one of the highest resolution images ever taken of Mars from orbit. The Medusae Fossae formation is believed to be formed of the fragmental ejecta of huge explosive volcanic eruptions. When subjected to intense wind-blasting over hundreds of millions of years, this material erodes easily once the uppermost tougher crust is breached. In the Mars Orbiter Camera (MOC) image shown on the right, the crust, or cap rock, can be seen in the upper right part of the picture. The finely-spaced ridges are similar to features on Earth called yardangs, which are formed by intense winds plucking individual grains from, and by wind-driven sand blasting particles off, sedimentary deposits.

    The MOC image was taken on October 30, 1997 at 11:05 AM PST, shortly after the Mars Global Surveyor spacecraft's 31st closest approach to Mars. The image covers an area 3.6 X 21.5 km (2.2 X 13.4 miles) at 3.6 m (12 feet) per picture element--craters only 11 m (36 feet, about the size of a swimming pool) across can be seen. The context image (left; the best Viking view of the area; VO 1 387S34) has a resolution of 240 m/pixel, or 67 times lower resolution than the MOC frame.

    Malin Space Science Systems (MSSS) and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.

  20. ANTIBODY FORMATION IN VITRO

    PubMed Central

    Fishman, M.

    1961-01-01

    Neutralizing activity against T2 bacteriophage appeared in cultures of lymph node cells from normal rats in response to their in vitro stimulation with a cell-free filtrate derived from homogenized rat macrophages which had been incubated with T2 bacteriophage. This activity was specifically directed against T2 bacteriophage. It resided in a fraction of the culture fluid which had the salting-out properties of serum globulin. Phage neutralization was inhibited by antibody specific for rat serum gamma globulin. Antibody production against T2 bacteriophage in cultures of lymph node cells from normal animals failed to occur if (a) T2 bacteriophage alone was added, (b) if the incubation period of macrophages and T2 phage was unduly shortened, (c) if the cell-free filtrate was heated at 80–100°C for 15 minutes, (d) if more than an optimal amount of T2 bacteriophage was added to the macrophages. Additional factors which prevented the formation of antibody were the heat inactivation of the lymph node cells or the addition to the culture medium of either streptomycin or ribonuclease. Finally, it was found that macrophages and lymph node cells had to be obtained from animals of one and the same species. All essential findings on the production of antibody to T2 bacteriophage in vitro could be confirmed by substitution of the chick embryo for the tissue culture medium. The results are discussed in terms of a possible mechanism of antibody production in which an RNAse-sensitive substance resulting from the interaction of macrophages and antigen is capable of stimulating antibody synthesis in lymphocytic cells. PMID:13893304

  1. Plasmapause formation at Saturn

    NASA Astrophysics Data System (ADS)

    Thomsen, M. F.; Mitchell, D. G.; Jia, X.; Jackman, C. M.; Hospodarsky, G.; Coates, A. J.

    2015-04-01

    Cassini observations during a rapid, high-latitude, dawnside pass from Saturn's lobe to inner magnetosphere on 25 June 2009 provide strong evidence for the formation of a "plasmapause" at Saturn by Vasyliunas-type nightside reconnection of previously mass-loaded flux tubes. A population of hot, tenuous plasma that lies between the lobe and the dense inner magnetospheric plasma is consistent with a region formed by very recent injection from a reconnection region in the tail, including low density, high temperature, supercorotational flow, a significant O+ content, and the near-simultaneous observation of enhanced Saturn kilometric radiation emissions. The sharp boundary between that region and the cool dense inner magnetospheric plasma thus separates flux tubes that were involved in the reconnection from those that successfully traversed the nightside without mass loss. This event demonstrates that tail reconnection can strip off inner magnetospheric plasma in to at least dipole L = 8.6. Clear evidence of flux tube interchange driven by the sharp boundary is found, both inward moving flux tubes of hotter plasma and, for the first time, the outward moving cool population. The outward moving cool regions have azimuthal sizes less than 1 RS, were probably created within the past 1.2 h, and have outflow speeds greater than about 5 km/s. At the outer edge of the reconnected region, there is also a possible signature of Dungey-type lobe reconnection following the initial Vasyliunas-type reconnection. Observations from this event are entirely consistent with previously described global MHD simulations of tail reconnection, plasmoid departure, and Saturnward injection of reconnected flux.

  2. Planet formation and searches

    NASA Astrophysics Data System (ADS)

    Montgomery, Ryan Michael

    2009-08-01

    This thesis explores the possibilities for discovery of terrestrial-mass planets in the habitable zones of their host stars. Towards this aim, we present the results of three projects and discuss another two preliminary studies of further explorations. In so doing, we explore a fairly comprehensive range of possibilities regarding the formation and detection of terrestrial- mass planets in the habitable zone. We first study the potential for terrestrial planets to form in situ in and around the habitable zones of M-dwarf stars. We proceed to explore the feasibility of searches for these planets using the transit method via Monte- Carlo simulations. We find that M-dwarfs pose an interesting challenge for study: being inherently dim, widely spread on the sky, and photometrically variable. We present results of simulated ground-based transit search campaigns as well as simulated searches from a modest satellite mission. Our second project is a straightforward extension of the previous study: a collaborative effort to search for transit signals around the nearest M-dwarf: Proxima Centauri. We describe our observations as well as the Monte-Carlo analysis used to place constraints on the possible planetary radii and periods. Our third project is a search for transiting extra-solar Jovian planets using the Rossiter-McLaughlin effect. We search through the private Keck radial- velocity datasets for undiscovered Rossiter-McLaughlin signals. We present our results in the form of both strong null-result datasets as well as potential transiting systems. We then briefly analyze these larger Jovian planets for potential to harbor potentially habitable terrestrial satellites. Our final preliminary analysis looks into the potential for the Large Synoptic Survey Telescope to detect transiting Neptune-mass planets orbiting M-dwarfs which could then lead to terrestrial-mass planet detections. The sum of these efforts is a comprehensive investigation into the likelihood and

  3. Formative Assessment Probes: Is It a Rock? Continuous Formative Assessment

    ERIC Educational Resources Information Center

    Keeley, Page

    2013-01-01

    A lesson plan is provided for a formative assessment probe entitled "Is It a Rock?" This probe is designed for teaching elementary school students about rocks through the use of a formative assessment classroom technique (FACT) known as the group Frayer Model. FACT activates students' thinking about a concept and can be used to…

  4. The Formation of Galactic Bulges

    NASA Astrophysics Data System (ADS)

    Carollo, C. Marcella; Ferguson, Henry C.; Wyse, Rosemary F. G.

    2000-03-01

    Part I. Introduction: What are galactic bulges?; Part II. The Epoch of Bulge Formation: Origin of bulges; Deep sub-mm surveys: High-z ULIRGs and the formation of spheroids; Ages and metallicities for stars in the galactic bulge; Integrated stellar populations of bulges: First results; HST-NICMOS observations of galactic bulges: Ages and dust; Inside-out bulge formation and the origin of the Hubble sequence; Part III. The Timescales of Bulge Formation: Constraints on the bulge formation timescale from stellar populations; Bulge building with mergers and winds; Role of winds, starbursts, and activity in bulge formation; Dynamical timescales of bulge formation; Part IV. Physical Processes in Bulge Formation: the role of bars for secular bulge formation; Bars and boxy/peanut-shaped bulges: an observational point of view; Boxy- and peanut-shaped bulges; A new class of bulges; The role of secondary bars in bulge formation; Radial transport of molecular gas to the nuclei of spiral galaxies; Dynamical evolution of bulge shapes; Two-component stellar systems: Phase-space constraints; Central NGC 2146 - a firehose-type bending instability?; Bulge formation: the role of the multi-phase ISM; Global evolution of a self-gravitating multi-phase ISM in the central kpc region of galaxies; Part V. Bulge Phenomenology: Bulge-disk decomposition of spiral galaxies in the near-infrared; The triaxial bulge of NGC 1371; The bulge-disk orthogonal decoupling in galaxies: NGC 4698 and NGC 4672; The kinematics and the origin of the ionized gas in NGC 4036; Optically thin thermal plasma in the galactic bulge; X-ray properties of bulges; The host galaxies of radio-loud AGN; The centers of radio-loud early-type galaxies with HST; Central UV spikes in two galactic spheroids; Conference summary: where do we stand?

  5. The formation of Pangea

    NASA Astrophysics Data System (ADS)

    Stampfli, G. M.; Hochard, C.; Vérard, C.; Wilhem, C.; vonRaumer, J.

    2013-05-01

    The making of Pangea is the result of large-scale amalgamation of continents and micro-continents, which started at the end of the Neoproterozoic with the formation of Gondwana. As pieces were added to Gondwana on its South-American, Antarctica and Australia side, ribbon-like micro-continents were detached from its African and South-Chinese side: Cadomia in the late Neoproterozoic, Avalonia and Hunia in the Ordovician, Galatia in the Devonian and Cimmeria in the Permian. Cadomia was re-accreted to Gondwana, but the other ribbon-continents were accreted to Baltica, North-China, Laurussia or Laurasia. Finding the origin of these numerous terranes is a major geological challenge. Recently, a global plate tectonic model was developed together with a large geological/geodynamic database, at the Lausanne University, covering the last 600 Ma of the Earth's history. Special attention was given to the placing of Gondwana derived terranes in their original position, using all possible constraints. We propose here a solution for the Variscan terranes, another paper deals with the Altaids. The Galatian super-terrane was detached from Gondwana in the Devonian, during the opening of Paleotethys, and was quickly separated into four sub-terranes that started to by-pass each other. The leading terranes collided at the end of the Devonian with the Hanseatic terrane detached from Laurussia. In the Carboniferous, Gondwana started to impinge onto the amalgamated terranes, creating the Variscan chain and the Pangean super-continent. East of Spain Paleotethys remained opened until the Triassic, subducting northward under Laurasia. Roll-back of the Paleotethyan slab triggered the collapse of most of the European Variscan orogen, which was replaced by series of Permian rifts, some of them becoming oceanized back-arc basins during the Triassic. Major force changes at the Pangean plate limits at the end of the Triassic provoked its break-up, through the opening of the proto

  6. An Upper Turonian fine-grained shallow marine stromatolite bed from the Muñecas Formation, Northern Iberian Ranges, Spain

    NASA Astrophysics Data System (ADS)

    Rodríguez-Martínez, M.; Sánchez, F.; Walliser, E. O.; Reitner, J.

    2012-07-01

    A fine-grained stromatolite bed, laterally continuous on the kilometer scale and with small synoptic relief, crops out in the Muñecas Formation in the Northern Iberian Ranges. The Muñecas Fm. was deposited during the late Turonian on a shallow water platform in the Upper Cretaceous intracratonic Iberian basin. The stromatolite bed has a tabular to domed biostromal macrostructure. Its internal mesostructure consists of planar, wavy to hemispherical stromatoids that display a broad spectrum of microstructures, including dense micrite, bahamite peloids, peloidal to clotted microfabrics, irregular micritic-wall tubes, which are suggestive of algae and filamentous microframeworks, which are suggestive of filamentous cyanobacteria. Various stromatolite growth stages have been linked to the dominance of different accretion processes. The accretion of the entire fine-grained stromatolite involves a complex mosaic of processes: trapping and binding of quartz-silt grains and bahamites, which form the agglutinated parts of some laminae, and microbially induced precipitation, which forms spongiostromic and micritic laminae. Tubiform and filamentous microframeworks resembling porostromatate or skeletal stromatolitic growth were also recognized. Laser ICP-MS measurements of Al, Si, Mg, Mn, Sr, S and Fe were analyzed to detect the influence of siliciclastic inputs and major trends during stromatolite accretion. Carbon and oxygen isotopic compositions from the stromatolite and associated facies were used to identify possible microbial signatures. These data describes a unique and well-preserved example of a shallow marine Upper Turonian fine-grained stromatolite.

  7. Archean deep-water depositional system: interbedded and banded iron formation and clastic turbidites in the Barberton Greenstone Belt, South Africa

    NASA Astrophysics Data System (ADS)

    Zentner, Danielle; Lowe, Donald

    2013-04-01

    The 3.23 billion year old sediments in the Barberton greenstone belt, South Africa include some of the world's oldest known deep-water deposits. Unique to this locality are turbidites interbedded with banded iron formation (BIF) and banded ferruginous chert (BFC). This unusual association may provide clues for reconstructing Archean deep-water depositional settings. For our study we examined freshly drilled core in addition to measuring ~500 m of outcrop exposures along road cuts. The stacking pattern follows an overall BIF to BFC to amalgamated turbidite succession, although isolated turbidites do occur throughout the sequence. The turbidites are predominately massive, and capped with thin, normally graded tops that include mud rip-ups, chert plates, and ripples. The lack of internal stratification and the amalgamated character suggests emplacement by surging high-density turbidity currents. Large scours and channels are absent and bedding is tabular: the flows were collapsing with little turbulence reaching the bed. In contrast, field evidence indicates the BIF and BFC most likely precipitated directly out of the water column. Preliminary interpretations indicate the deposits may be related to a pro-deltaic setting. (1) Deltaic systems can generate long-lived, high volume turbidity currents. (2) The contacts between the BIF, BFC, and turbidite successions are gradual and inter-fingered, possibly representing lateral facies relationships similar to modern pro-delta environments. (3) Putative fan delta facies, including amalgamated sandstone and conglomerate, exist stratigraphically updip of the basinal sediments.

  8. Pebbly mudstones in the Cretaceous Pigeon Point Formation, western California: a study in the transitional stages from submarine slumps to cohesive debris flows

    NASA Astrophysics Data System (ADS)

    López-Gamundí, Oscar R.

    1993-04-01

    The pebbly mudstones in the Late Cretaceous Pigeon Point Formation originated by slumping and related debris-flow processes in a submarine canyon/slope depositional system. The sedimentary characteristics of the pebbly mudstones (PM) enable the distinction of two main varieties: (a) heterogeneous or "patchy" pebbly mudstones (PPM) exhibiting irregular bed geometries and diffuse to irregular bed contacts, with maximum clast sizes in intraformational boulder-sized population, including abundant rip-up mudstone and sandstone clasts with common soft sediment deformations; (b) homogeneous pebbly mudstones (HPM) with tabular bed geometries, non-erosive and almost flat bed contacts, maximum clast sizes in extraformational pebble-sized fraction and scarce to absent soft-sediment deformations. The two varieties of pebbly mudstone represent the mechanical transition from slumps to cohesive debris flows. The presence of abundant intraformational clasts and disrupted, yet preserved slump-fold features in the PPM suggest that this facies represents a stage closer to the slump end-member. As the shear-strain progressed and a fully remolded cohesive debris flow developed, an almost complete disaggregation of the poorly consolidated sand and mud clasts and the incorporation into the remolded "matrix" phase took place.

  9. SAS FORMATS: USES AND ABUSES

    EPA Science Inventory

    SAS formats are a very powerful tool. They allow you to display the data in a more readable manner without modifying it. Formats can also be used to group data into categories for use in various procedures like PROC FREQ, PROC TTEST, and PROC MEANS (as a class variable). As ...

  10. SAS FORMATS: USES AND ABUSES

    EPA Science Inventory

    SAS formats are a very powerful tool. They allow you to display the data in a more readable manner without modifying it. Formats can also be used to group data into categories for use in various procedures like PROC FREQ, PROC TTEST, and PROC MEANS (as a class variable). As w...

  11. Portable File Format (PFF) specifications.

    SciTech Connect

    Dolan, Daniel H.,

    2015-02-01

    Created at Sandia National Laboratories, the Portable File Format (PFF) allows binary data transfer across computer platforms. Although this capability is supported by many other formats, PFF files are still in use at Sandia, particularly in pulsed power research. This report provides detailed PFF specifications for accessing data without relying on legacy code.

  12. Bibliography Formatting Software: An Update.

    ERIC Educational Resources Information Center

    Stigleman, Sue

    1993-01-01

    Discusses software used for formatting bibliographies and describes 52 programs. Information provided includes type of operating system required, publication formats, citation styles, ability to arrange by subject, use of downloaded references, network versions, costs, and plans for future changes. A directory of the programs and producers is…

  13. Formation Algorithms and Simulation Testbed

    NASA Technical Reports Server (NTRS)

    Wette, Matthew; Sohl, Garett; Scharf, Daniel; Benowitz, Edward

    2004-01-01

    Formation flying for spacecraft is a rapidly developing field that will enable a new era of space science. For one of its missions, the Terrestrial Planet Finder (TPF) project has selected a formation flying interferometer design to detect earth-like planets orbiting distant stars. In order to advance technology needed for the TPF formation flying interferometer, the TPF project has been developing a distributed real-time testbed to demonstrate end-to-end operation of formation flying with TPF-like functionality and precision. This is the Formation Algorithms and Simulation Testbed (FAST) . This FAST was conceived to bring out issues in timing, data fusion, inter-spacecraft communication, inter-spacecraft sensing and system-wide formation robustness. In this paper we describe the FAST and show results from a two-spacecraft formation scenario. The two-spacecraft simulation is the first time that precision end-to-end formation flying operation has been demonstrated in a distributed real-time simulation environment.

  14. The Apennine Bench Formation revisited

    NASA Technical Reports Server (NTRS)

    Spudis, P. D.; Hawke, B. R.

    1985-01-01

    The Apennine Bench Formation consists of pre-mare light plains materials that crop out south of the crater Archimedes, inside the Imbrium basin. This material was ascribed to either impact or volcanic origins. The characteristics of Apollo 15 KREEP basalts and the Apennine Bench Formation are reviewed to determine whether their characteristics are compatible with a volcanic origin.

  15. Star formation in the multiverse

    SciTech Connect

    Bousso, Raphael; Leichenauer, Stefan

    2009-03-15

    We develop a simple semianalytic model of the star formation rate as a function of time. We estimate the star formation rate for a wide range of values of the cosmological constant, spatial curvature, and primordial density contrast. Our model can predict such parameters in the multiverse, if the underlying theory landscape and the cosmological measure are known.

  16. Tariffs Formation on oil transportation

    NASA Astrophysics Data System (ADS)

    Glyzina, T. S.; Kolbysheva, Yu. V.; Grivtsova, I. S.; Dmitrieva, N. V.

    2016-09-01

    Oil transportation via trunk pipelines is an important part of the oil industry's activity. The main instrument of tariff regulation is the method of tariffs formation. Three methods of tariffs formation such as the method of economically justified costs (the Cost plus method), the method of economically justified return on investment capital (the RAB method), and the method of tariffs indexation were considered.

  17. Formative Assessment: A Critical Review

    ERIC Educational Resources Information Center

    Bennett, Randy Elliot

    2011-01-01

    This paper covers six interrelated issues in formative assessment (aka, "assessment for learning"). The issues concern the definition of formative assessment, the claims commonly made for its effectiveness, the limited attention given to domain considerations in its conceptualisation, the under-representation of measurement principles in that…

  18. Sibling similarity in family formation.

    PubMed

    Raab, Marcel; Fasang, Anette Eva; Karhula, Aleksi; Erola, Jani

    2014-12-01

    Sibling studies have been widely used to analyze the impact of family background on socioeconomic and, to a lesser extent, demographic outcomes. We contribute to this literature with a novel research design that combines sibling comparisons and sequence analysis to analyze longitudinal family-formation trajectories of siblings and unrelated persons. This allows us to scrutinize in a more rigorous way whether sibling similarity exists in family-formation trajectories and whether siblings' shared background characteristics, such as parental education and early childhood family structure, can account for similarity in family formation. We use Finnish register data from 1987 through 2007 to construct longitudinal family-formation trajectories in young adulthood for siblings and unrelated dyads (N = 14,257 dyads). Findings show that family formation is moderately but significantly more similar for siblings than for unrelated dyads, also after controlling for crucial parental background characteristics. Shared parental background characteristics add surprisingly little to account for sibling similarity in family formation. Instead, gender and the respondents' own education are more decisive forces in the stratification of family formation. Yet, family internal dynamics seem to reinforce this stratification such that siblings have a higher probability to experience similar family-formation patterns. In particular, patterns that correspond with economic disadvantage are concentrated within families. This is in line with a growing body of research highlighting the importance of family structure in the reproduction of social inequality.

  19. Cyanide Formation by Chromobacterium violaceum

    PubMed Central

    Michaels, Ruth; Corpe, W. A.

    1965-01-01

    Michaels, Ruth (Columbia University, New York, N.Y.), and W. A. Corpe. Cyanide formation by Chromobacterium violaceum. J. Bacteriol. 89:106–112. 1965.—The formation of cyanide by a Chromobacterium violaceum strain was studied with growing cultures and with nonproliferating cells grown in complex and chemically defined media. Most of the cyanide was produced during the log-phase growth of the organism, and accumulated in the culture supernatant fluid. A synergistic effect of glycine and methionine on cyanide formation in a chemically defined medium was observed, and the amount of cyanide formed was found to be dependent on the concentrations of the two substances. Cyanide formation by nonproliferating cells was stimulated by preincubation with glycine and methionine. Cyanide formation by adapted cells in the presence of glycine and methionine was stimulated by succinate, malate, or fumarate, and depressed by azide and 2,4-dinitrophenol. Methionine could be replaced by betaine, dimethylglycine, and choline. PMID:14255648

  20. Physics of primordial star formation

    NASA Astrophysics Data System (ADS)

    Yoshida, Naoki

    2012-09-01

    The study of primordial star formation has a history of nearly sixty years. It is generally thought that primordial stars are one of the key elements in a broad range of topics in astronomy and cosmology, from Galactic chemical evolution to the formation of super-massive blackholes. We review recent progress in the theory of primordial star formation. The standard theory of cosmic structure formation posits that the present-day rich structure of the Universe developed through gravitational amplification of tiny matter density fluctuations left over from the Big Bang. It has become possible to study primordial star formation rigorously within the framework of the standard cosmological model. We first lay out the key physical processes in a primordial gas. Then, we introduce recent developments in computer simulations. Finally, we discuss prospects for future observations of the first generation of stars.

  1. Stratigraphic sections of the Phosphoria formation in Utah, 1947-48

    USGS Publications Warehouse

    McKelvey, Vincent Ellis; Smith, L.E.; Kinney, D.M.; Huddle, J.W.; Hosford, G.F.; Sears, R.S.; Sprouse, D.P.; Steward, M.D.

    1952-01-01

    As part of a comprehensive investigation of the phosphate deposits of the western field begun in 1947, the U. S. Geological survey has measured an sampled the full thickness of the Permian Phosphoria formation and its partial correlative, the Park City formation, at many localities in Utah and other western states. Although these data will not be fully analyzed for several years, segments of the data, accompanied by little or no interpretation, will be published as preliminary reports. This report, which contains abstracts of many of the sections measured in northeastern Utah (pl. 1), is one of this series. The field and laboratory procedures adopted in these investigations are described rather fully in a companion report (McKelvey and others, 1952). A large number of people have taken part in this investigation. J. B. Collins, R. A. Gulbrandsen, R. A. Hoppin, J. A. Noel, F. W. O'Malley, O. A. Payne, J. F. Rominger, R. P. Sheldon, J. E. Smedley, and R. G. Waring participated in the description of strata and collection of samples referred to in this report. D. B. Dimick, H. A. Larsen, and T. K. Rigby assisted in the preparation of trenches and the crushing and splitting of samples in the field. The laboratory preparation of samples for chemical analysis was done in Denver, Colo., under the direction of W. P. Huleatt. Most of the chemical analyses reported herein were made for the Survey by the U. S. Bureau of Mines at the Northwest Electrodevelopment Laboratory, Albany, Oreg., under the direction of S. M. Shelton and M. L. Wright. All the samples from one locality (Brazer Canyon) were analyzed in the Chemical Laboratory of the Tennessee Valley Authority at Wilson Dam, Ala. Some of the Al2O3, Fe2O3, and loss-on-ignition analyses were made in the Trace Elements Section laboratory of the Survey in Washington, D. C., under the direction of J. C. Rabbitt by chemists I. Barlow, A Caemmerer, J. Greene, N. Guttag, and E. H. Humphrey. The spectrographic analyses were made by

  2. DataUp: A tool to help researchers describe and share tabular data

    PubMed Central

    Strasser, Carly; Kunze, John; Abrams, Stephen; Cruse, Patricia

    2014-01-01

    Scientific datasets have immeasurable value, but they lose their value over time without proper documentation, long-term storage, and easy discovery and access. Across disciplines as diverse as astronomy, demography, archeology, and ecology, large numbers of small heterogeneous datasets (i.e., the long tail of data) are especially at risk unless they are properly documented, saved, and shared. One unifying factor for many of these at-risk datasets is that they reside in spreadsheets. In response to this need, the California Digital Library (CDL) partnered with Microsoft Research Connections and the Gordon and Betty Moore Foundation to create the DataUp data management tool for Microsoft Excel. Many researchers creating these small, heterogeneous datasets use Excel at some point in their data collection and analysis workflow, so we were interested in developing a data management tool that fits easily into those work flows and minimizes the learning curve for researchers. The DataUp project began in August 2011. We first formally assessed the needs of researchers by conducting surveys and interviews of our target research groups: earth, environmental, and ecological scientists. We found that, on average, researchers had very poor data management practices, were not aware of data centers or metadata standards, and did not understand the benefits of data management or sharing. Based on our survey results, we composed a list of desirable components and requirements and solicited feedback from the community to prioritize potential features of the DataUp tool. These requirements were then relayed to the software developers, and DataUp was successfully launched in October 2012. PMID:25653834

  3. DataUp: A tool to help researchers describe and share tabular data.

    PubMed

    Strasser, Carly; Kunze, John; Abrams, Stephen; Cruse, Patricia

    2014-01-01

    Scientific datasets have immeasurable value, but they lose their value over time without proper documentation, long-term storage, and easy discovery and access. Across disciplines as diverse as astronomy, demography, archeology, and ecology, large numbers of small heterogeneous datasets (i.e., the long tail of data) are especially at risk unless they are properly documented, saved, and shared. One unifying factor for many of these at-risk datasets is that they reside in spreadsheets. In response to this need, the California Digital Library (CDL) partnered with Microsoft Research Connections and the Gordon and Betty Moore Foundation to create the DataUp data management tool for Microsoft Excel. Many researchers creating these small, heterogeneous datasets use Excel at some point in their data collection and analysis workflow, so we were interested in developing a data management tool that fits easily into those work flows and minimizes the learning curve for researchers. The DataUp project began in August 2011. We first formally assessed the needs of researchers by conducting surveys and interviews of our target research groups: earth, environmental, and ecological scientists. We found that, on average, researchers had very poor data management practices, were not aware of data centers or metadata standards, and did not understand the benefits of data management or sharing. Based on our survey results, we composed a list of desirable components and requirements and solicited feedback from the community to prioritize potential features of the DataUp tool. These requirements were then relayed to the software developers, and DataUp was successfully launched in October 2012.

  4. The Tabular Mode: Not Just Another Way To Represent a Function.

    ERIC Educational Resources Information Center

    Hines, Ellen; Klanderman, David B.; Khoury, Helen

    2001-01-01

    Reports on two investigations examining students' thinking processes with regard to functions. Concludes that students often relied on a table or some variation of a table as a cognitive link advancing the development of their reasoning about underlying function relationships. (Author/MM)

  5. Calcification, storm damage and population resilience of tabular corals under climate change.

    PubMed

    Madin, Joshua S; Hughes, Terry P; Connolly, Sean R

    2012-01-01

    Two facets of climate change--increased tropical storm intensity and ocean acidification--are expected to detrimentally affect reef-building organisms by increasing their mortality rates and decreasing their calcification rates. Our current understanding of these effects is largely based on individual organisms' short-term responses to experimental manipulations. However, predicting the ecologically-relevant effects of climate change requires understanding the long-term demographic implications of these organism-level responses. In this study, we investigate how storm intensity and calcification rate interact to affect population dynamics of the table coral Acropora hyacinthus, a dominant and geographically widespread ecosystem engineer on wave-exposed Indo-Pacific reefs. We develop a mechanistic framework based on the responses of individual-level demographic rates to changes in the physical and chemical environment, using a size-structured population model that enables us to rigorously incorporate uncertainty. We find that table coral populations are vulnerable to future collapse, placing in jeopardy many other reef organisms that are dependent upon them for shelter and food. Resistance to collapse is largely insensitive to predicted changes in storm intensity, but is highly dependent on the extent to which calcification influences both the mechanical properties of reef substrate and the colony-level trade-off between growth rate and skeletal strength. This study provides the first rigorous quantitative accounting of the demographic implications of the effects of ocean acidification and changes in storm intensity, and provides a template for further studies of climate-induced shifts in ecosystems, including coral reefs.

  6. Stratigraphic framework and estuarine depositional environments of the Miocene Bear Lake Formation, Bristol Bay Basin, Alaska: Onshore equivalents to potential reservoir strata in a frontier gas-rich basin

    USGS Publications Warehouse

    Finzel, E.S.; Ridgway, K.D.; Reifenstuhl, R.R.; Blodgett, R.B.; White, J.M.; Decker, P.L.

    2009-01-01

    The Miocene Bear Lake Formation is exposed along the coast and mountains of the central Alaska Peninsula and extends offshore as part of the Bristol Bay Basin. The Bear Lake Formation is up to 2360 m (7743 ft) thick in an offshore well and is considered to have the highest reservoir potential in this gasrich frontier basin. Our new macrofossil and palynological data, collected in the context of measured stratigraphic sections, allow us to construct the first chronostratigraphic framework for this formation. Biostratigraphic age assignments for the numerous, commonly isolated, onshore exposures of the Bear Lake Formation show that deposition initiated sometime before the middle Miocene (15 Ma) and extended to possibly the earliest Pliocene. The bulk of the Bear Lake Formation, however, was deposited during the middle and late Miocene based on our new findings. We interpret the Bear Lake Formation as the product of a regional transgressive estuarine depositional system based on lithofacies analysis. The lower part of the formation is characterized by trough cross-stratified sandstone interbedded with coal and pedogenic mudstone deposited in fluvial and swamp environments of the uppermost parts of the estuarine system. The lower-middle part of the formation is dominated by nonbioturbated, wavy- and flaser-bedded sandstone and siltstone that were deposited in supratidal flat environments. The uppermiddle part of the Bear Lake Formation is characterized by inclined heterolithic strata and coquinoid mussel beds that represent tidal channel environments in the middle and lower tracts of the estuarine system. The uppermost part of the formation consists of tabular, bioturbated sandstone with diverse marine invertebrate macrofossil faunas. We interpret this part of the section as representing the subtidal tract of the lower estuarine system and possibly the adjacent shallow inner shelf. A comparison of our depositional framework for the Bear Lake Formation with core and

  7. Dissipative processes in galaxy formation.

    PubMed Central

    Silk, J

    1993-01-01

    A galaxy commences its life in a diffuse gas cloud that evolves into a predominantly stellar aggregation. Considerable dissipation of gravitational binding energy occurs during this transition. I review here the dissipative processes that determine the critical scales of luminous galaxies and the generation of their morphology. The universal scaling relations for spirals and ellipticals are shown to be sensitive to the history of star formation. Semiphenomenological expressions are given for star-formation rates in protogalaxies and in starbursts. Implications are described for elliptical galaxy formation and for the evolution of disk galaxies. PMID:11607396

  8. Antihydrogen Formation using Cold Plasmas

    SciTech Connect

    Madsen, N.; Bowe, P.D.; Hangst, J.S.; Amoretti, M.; Carraro, C.; Macri, M.; Testera, G.; Variola, A.; Amsler, C.; Johnson, I.; Pruys, H.; Regenfus, C.; Bonomi, G.; Bouchta, A.; Doser, M.; Kellerbauer, A.; Landua, R.; Cesar, C.L.; Charlton, M.; Joergensen, L.V.

    2004-10-20

    Antihydrogen, the antimatter counterpart of the hydrogen atom, can be formed by mixing cold samples of antiprotons and positrons. In 2002 the ATHENA collaboration succeeded in the first production of cold antihydrogen. By observing and imaging the annihilation products of the neutral, non-confined, antihydrogen atoms annihilating on the walls of the trap we can observe the production in quasi-real-time and study the dynamics of the formation mechanism. The formation mechanism strongly influences the final state of the formed antihydrogen atoms, important for future spectroscopic comparison with hydrogen. This paper briefly summarizes the current understanding of the antihydrogen formation in ATHENA.

  9. Dynamics of rock varnish formation

    SciTech Connect

    Raymond, R. Jr.; Reneau, S.L.; Guthrie, G.D. Jr.; Bish, D.L.; Harrington, C.D.

    1991-01-01

    Our studies of rock varnish from the southwestern United States suggest that the Mn-phase in rock varnish has neither the chemistry nor the crystal structure of birnessite. Rather, the Mn-rich phase is non-crystalline and contains Ba, Ca, Fe, Al, and P. Unknowns concerning the formation of this non-crystalline Mn phase must be resolved before researchers are able to define chemical parameters of rock varnish formation based upon conditions of formation of the Mn phase. 6 refs., 9 figs.

  10. BOREAS TGB-4 NSA-BVP Tower Flux and Meteorological Data

    NASA Technical Reports Server (NTRS)

    Roulet, Nigel T.; Hall, Forrest G. (Editor); Huemmrich, Karl (Editor); Conrad, Sara K. (Editor)

    2000-01-01

    The BOReal Ecosystem-Atmosphere Study Trace Gas Biogeochemistry (BOREAS TGB-4) team measured the exchange of heat, water, and CO2 between a boreal forest beaver pond and the atmosphere in the Northern Study Area (NSA) for the ice-free period of BOREAS. The data cover the period of 28-May to 18-Sep-1994. The data are available in tabular ASCII files.

  11. BOREAS TGB-1 NSA SF6 Chamber Flux Data

    NASA Technical Reports Server (NTRS)

    Crill, Patrick; Varner, Ruth K.; Hall, Forrest G. (Editor); Conrad, Sara K. (Editor)

    2000-01-01

    The BOREAS TGB-1 team made several chamber and tower measurements of trace gases at sites in the BOREAS NSA. This data set contains sulfur hexafluoride (SF6) dark chamber flux measurements at the NSA-OJP and NSA-YJP sites from 16-May through 13-Sep-1994. Gas samples were extracted approximately every 7 days from dark chambers and analyzed at the NSA lab facility. The data are provided in tabular ASCII files.

  12. BOREAS TF-2 SSA-OA Tethersonde Meteorological and Ozone Data

    NASA Technical Reports Server (NTRS)

    Arnold, A. James; Mickle, Robert E.; Hall, Forrest G. (Editor); Huemmrich, Karl (Editor)

    2000-01-01

    The BOReal Ecosystem-Atmosphere Study Tower Flux-2 (BOREAS TF-2) team collected meteorological and ozone measurements from instruments mounted below a tethered balloon. These data were collected at the Southern Study Area Old Aspen (SSA-OA) site to extend meteorological and ozone measurements made from the flux tower to heights of 300 m. The tethersonde operated during the fall of 1993 and the spring, summer, and fall of 1994. The data are available in tabular ASCII files.

  13. BOREAS TF-4 CO2 and CH4 Chamber Flux Data from the SSA

    NASA Technical Reports Server (NTRS)

    Anderson, Dean; Striegl, Robert; Wickland, Kimberly; Hall, Forrest G. (Editor); Conrad, Sara (Editor)

    2000-01-01

    The BOREAS TF-4 team measured fluxes of CO2 and CH4 across the soil-air interface in four ages of jack pine forest at the BOREAS SSA during August 1993 to March 1995. Gross and net flux of CO2 and flux of CH4 between soil and air are presented for 24 chamber sites in mature jack pine forest, 20-year-old, 4-year-old, and clear cut areas. The data are stored in tabular ASCII files.

  14. BOREAS TF-1 SSA-OA Weekly Tower CH4 and N2O Flux

    NASA Technical Reports Server (NTRS)

    Thurtell, George; Edwards, Grant; Simpson, George; Hall, Forrest G. (Editor); Huemmrich, Karl (Editor)

    2000-01-01

    The BOREAS TF-1 team collected various trace gas and energy flux data in its efforts to characterize the temporal energy and gas exchanges that occurred over the SSA-OA site. This data set contains methane (CH4) and nitrous oxide (N2O) fluxes that were measured at the BOREAS SSA-OA site. These fluxes were measured from 16-Apr to 16-Sep-1994. The data were averaged to weekly values and are available in tabular ASCII files.

  15. BOREAS TGB-1 NSA CH4 and CO2 Chamber Flux Data

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G. (Editor); Conrad, Sara K. (Editor); Crill, Patrick; Varner, Ruth K.

    2000-01-01

    The BOREAS TGB-1 team made methane (CH4) and carbon dioxide (CO2) dark chamber flux measurements at the NSA-OJP, NSA-OBS, NSA-BP, and NSA-YJP sites from 16-May-1994 through 13-Sep-1994. Gas samples were extracted approximately every 7 days from dark chambers and analyzed at the NSA lab facility. The data are provided in tabular ASCII files.

  16. BOREAS TF-11 SSA-Fen Soil Surface CO2 Flux Data

    NASA Technical Reports Server (NTRS)

    Arkebauer, Timothy J.; Hall, Forrest G. (Editor); Knapp, David E. (Editor)

    2000-01-01

    The BOREAS TF-11 team gathered a variety of data to complement its tower flux measurements collected at the SSA-Fen site. These data are soil surface CO 2 flux data at the SSA-Fen site from 27- May-1994 to 23-Sep-1994 and from 13-May-1995 to 03-Oct-1995. A portable gas exchange system was used to make these measurements. The data are stored in tabular ASCII files.

  17. BOREAS TF-11 SSA-Fen 1995 Leaf Area Index Data

    NASA Technical Reports Server (NTRS)

    Arkebauer, Timothy J.; Hall, Forrest G. (Editor); Knapp, David E. (Editor)

    2000-01-01

    The BOREAS TF-11 team gathered a variety of data to complement its tower flux measurements collected at the SSA-Fen site. These data are LAI measurements made by the TF-11 team throughout the 1995 growing season. The data include the LAI of plants that fall into six categories: total, Carex spp., Betula pumila, Menyanthes trifoliata, Salix spp., and other vascular plants. The data are stored in tabular ASCII files.

  18. BOREAS TF-11 SSA-Fen Leaf Gas Exchange Data

    NASA Technical Reports Server (NTRS)

    Arkebauer, Timothy J.; Hall, Forrest G. (Editor); Knapp, David E. (Editor)

    2000-01-01

    The BOREAS TF-11 team gathered a variety of data to complement its tower flux measurements collected at the SSA-Fen site. This data set contains single-leaf gas exchange data from the SSA-Fen site during 1994 and 1995. These leaf gas exchange properties were measured for the dominant vascular plants using portable gas exchange systems. The data are stored in tabular ASCII files.

  19. BOREAS TE-22 Allometric Forest Survey Data

    NASA Technical Reports Server (NTRS)

    Shugart, H. H.; Nielsen, Eric; Hall, Forrest G. (Editor); Papagno, Andrea (Editor)

    2000-01-01

    The Boreal Ecosystem-Atmospheric Study (BOREAS) TE-22 (Terrestrial Ecology) team collected data sets in support of its efforts to characterize and interpret information on the forest structure of boreal vegetation in the Southern and Northern Study Areas (SSA and NSA) during the 1994 growing season. The data are stored in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

  20. County-based estimates of nitrogen and phosphorus content of animal manure in the United States for 1982, 1987, and 1992

    USGS Publications Warehouse

    Puckett, Larry; Hitt, Kerie; Alexander, Richard

    1998-01-01

    names that correspond to the FIPS codes. 2. Tabular component - Nine tab-delimited ASCII lookup tables of animal counts and nutrient estimates organized by 5-digit state/county FIPS (Federal Information Processing Standards) code. Another table lists the county names that correspond to the FIPS codes. The use of trade names is for identification purposes only and does not constitute endorsement by the U.S. Geological Survey.

  1. BOREAS Derived Surface Meteorological Data

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G. (Editor); Newcomer, Jeffrey A. (Editor); Twine, Tracy; Rinker, Donald; Knapp, David

    2000-01-01

    In 1995, the BOREAS science teams identified the need for a continuous surface meteorological and radiation data set to support flux and surface process modeling efforts. This data set contains actual, substituted, and interpolated 15-minute meteorological and radiation data compiled from several surface measurements sites over the BOREAS SSA and NSA. Temporally, the data cover 01-Jan-1994 to 31-Dec-1996. The data are stored in tabular ASCII files, and are classified as AFM-Staff data.

  2. BOREAS RSS-11 Ground Network of Sunphotometer Measurements

    NASA Technical Reports Server (NTRS)

    Markham, Brian L.; Hall, Forrest G. (Editor); Nickerson, Jaime (Editor); Schafer, Joel; Smith, David E. (Technical Monitor)

    2000-01-01

    The BOREAS RSS-11 team operated a network of five automated (Cimel) and two hand-held (Miami) solar radiometers from 1994 to 1996 during the BOREAS field campaigns. The data provide aerosol optical depth measurements, size distribution, phase function, and column water vapor amounts over points in northern Saskatchewan and Manitoba, Canada. The data are useful for the correction of remotely sensed aircraft and satellite images. The data are provided in tabular ASCII files.

  3. Formate dehydrogenase from Pseudomonas oxalaticus.

    PubMed

    Müller, U; Willnow, P; Ruschig, U; Höpner, T

    1978-02-01

    Formate dehydrogenase (EC 1.2.1.2) from Pseudomonas oxalaticus has been isolated and characterized. The enzyme (molecular weight 315000) is a complex flavoprotein containing 2 FMN, 18--25 non-heme iron atoms and 15--20 acid-labile sulphides. In the last step of the purification, a sucrose gradient centrifugation, a second catalytically active species has been found apparently originating from a dissociation of the enzyme into two equal subunits. The enzyme is specific toward its natural substrate formate. It transfers electrons to NAD+, oxygen, ferricyanide, and a lot of nonphysiological acceptors (dyes). In addition electrons are transferred from NADH to these acceptors. The (reversible) removal of FMN requires a reduction step. Reincorporation has been followed by the reappearance of the reactivity against formate and by fluorescence titration. The deflavo enzyme also binds FAD and riboflavin. The resulting enzyme species show characteristic catalytic abilities. Activity against formate is peculiar to the FMN species. PMID:631130

  4. Results of Aluminosilicate Formation Testing

    SciTech Connect

    Wilmarth, W.R.

    2001-09-11

    The purpose of this work was to examine several experimental parameters of the formation of aluminosilicates under several tank chemistries, examine the conversion of crystalline phases, and determine inherent solubilities of certain crystal phases.

  5. Ultraviolet Mars Reveals Cloud Formation

    NASA Video Gallery

    Images from MAVEN's Imaging UltraViolet Spectrograph were used to make this movie of rapid cloud formation on Mars on July 9-10, 2016. The ultraviolet colors of the planet have been rendered in fal...

  6. A low diversity, seasonal tropical landscape dominated by conifers and peltasperms: Early Permian Abo Formation, New Mexico

    USGS Publications Warehouse

    DiMichele, W.A.; Chaney, D.S.; Nelson, W.J.; Lucas, S.G.; Looy, C.V.; Quick, K.; Jun, W.

    2007-01-01

    Walchian conifers (Walchia piniformis Sternberg, 1825) and peltasperms similar to Supaia thinnfeldioides White and cf. Supaia anomala White dominate floodplain deposits of a narrow stratigraphic interval of the middle Abo Formation, Lower Permian of central New Mexico. The plant fossils occur in thinly bedded units up to two meters thick, consisting of coarse siltstone to very fine sandstone with clay partings. Bedding is primarily tabular, thin, and bears rare ripple marks and trough cross beds. Bedding surfaces display mud cracks, raindrop imprints, horizontal and vertical burrows of invertebrates, and footprints of terrestrial vertebrates. These features indicate intermittent and generally unchannelized stream flow, with repeated exposure to air. Channels appear to have cannibalized one another on a slowly subsiding coastal plain. Conifers are dominant at three collecting sites and at three others Supaia dominates. Although each of these genera occurs in assemblages dominated by the other, there are no truly co-dominant assemblages. This pattern suggests alternative explanations. Landscapes could have consisted of a small-scale vegetational patchwork dominated almost monospecifically in any one patch, meaning that these plants could have coexisted across the landscape. On the other hand, conifer and supaioid dominance could have been temporally distinct, occurring during different episodes of sedimentation; although in the field there are no noticeable sedimentological differences between conifer-dominated and Supaia-dominated channel deposits, they may represent slightly different climatic regimes. The considerable morphological differences between conifers and Supaia suggest that the floristic patterns are not a taphonomic effect of the loss of a significant part of the original biodiversity. In general, the climate under which this vegetation developed appears to have been relatively warm and arid, based on the geology (pervasive red color [oxidation

  7. Variations in fluvial style in the Westwater Canyon Member, Morrison formation (Jurassic), San Juan basin, Colorado plateau

    USGS Publications Warehouse

    Miall, A.D.; Turner-Peterson, C. E.

    1989-01-01

    Techniques of architectural element analysis and lateral profiling have been applied to the fluvial Westwater Canyon Member of the Morrison Formation (Jurassic) in southern San Juan Basin. On a large scale, the sandstone-body architecture consists mainly of a series of tabular sandstone sheets 5-15 m thick and hundreds of meters wide, separated by thin fine-grained units. Internally these sheets contain lateral accretion surfaces and are cut by channels 10-20 m deep and at least 250 m wide. On a more detailed scale, interpretations made from large-scale photomosaics show a complex of architectural elements and bounding surfaces. Typical indicators of moderate- to high-sinuosity channels (lateral accretion deposits) coexist in the same outcrop with downstream-accreted macroform deposits that are typical of sand flats of low-sinuosity, multiple-channel rivers. Broad, deep channels with gently to steeply dipping margins were mapped in several of the outcrops by carefully tracing major bounding surfaces. Locally thick accumulations of plane-laminated and low-angle cross-laminated sandstone lithofacies suggest rapid flow, probably transitional to upper flow regime conditions. Such a depositional style is most typical of ephemeral rivers or those periodically undergoing major seasonal (or more erratic) stage fluctuations, an interpretation consistent with independent mineralogical evidence of aridity. Fining-upward sequences are rare in the project area, contrary to the descriptions of Campbell (1976). The humid alluvial fan model of Galloway (1978) cannot be substantiated and, similarly, the architectural model of Campbell (1976) requires major revision. Comparisons with the depositional architecture of the large Indian rivers, such as the Ganges and Brahmaputra, still seem reasonable, as originally proposed by Campbell (1976), although there is now convincing evidence for aridity and for major stage fluctuations, which differs both from those modern rivers and Campbell

  8. The depositional environment and petrology of the White Rim Sandstone Member of the Permian Cutler Formation, Canyonlands National Park, Utah

    USGS Publications Warehouse

    Steele-Mallory, B. A.

    1982-01-01

    The White Rim Sandstone Member of the Cutler Formation of Permian age in Canyonlands National Park, Utah, was deposited in coastal eolian and associated interdune environments. This conclusion is based on stratigraphic relationships primary sedimentary structures, and petrologic features. The White Rim consists of two major genetic units. The first represents a coastal dune field and the second represents related interdune ponds. Distinctive sedimentary structures of the coastal dune unit include large- to medium-scale, unidirectional, tabular-planar cross-bedding; high-index ripples oriented parallel to dip direction of the foresets; coarse-grained lag layers; avalanche or slump marks; and raindrop impressions. Cross-bedding measurements suggest the dunes were deposited as transverse ridges by a dominantly northwest to southeast wind. Distinctive sedimentary structures of the interdune pond unit include wavy, horizontally laminated bedding, adhesion ripples, and desiccation polygons. These features may have been produced by alternate wetting and drying of sediment during water-table fluctuations. Evidence of bioturbation is also present in this unit. Petrologic characteristics of the White Rim helped to define the depositional environment as coastal. A crinoid fragment was identified at one location; both units are enriched in heavy minerals, and small amounts of well rounded, reworked glauconite were found in the White Rim throughout the study area. Earlier work indicates that the White Rim sandstone is late Wolfcampian to early Leonardian in age. During this time, the Canyonlands area was located in a depositional area alternately dominated by marine and nonmarine environments. Results of this study suggest the White Rim represents a coastal dune field that was deposited by predominantly on-shore winds during a period of marine transgression.

  9. Star Formation Across Galactic Environments

    NASA Astrophysics Data System (ADS)

    Young, Jason

    2013-01-01

    I present here parallel investigations of star formation in AGN-free and quasar host galaxies. These environments are both insightful; quasars are among the most violent objects known, reshaping their host galaxies, while my sample of AGN-free star-forming galaxies ranges from systems larger than the Milky Way to dwarf star-forming galaxies. The AGN-free galaxies are drawn from the KPNO International Spectroscopic Survey, an Hα-selected, volume-limited survey was designed to avoid continuum luminosity bias. This work studies the KISS galaxies in mid- and far-IR using Spitzer IRAC and MIPS photometry. These IR bands are interesting because the UV light from young stars is reprocessed into thermal emission in the far-IR (24μm MIPS) by dust and into vibrational transition features in the mid-IR (8.0μm IRAC) by polycyclic aromatic hydrocarbons (PAHs). This work examines the efficiencies of PAH and dust emission as tracers of star-formation. I find that the efficiency of PAH as a star-formation tracer varies with galactic stellar mass, while thermal dust has no systematic dependance on galactic mass. My study of quasar host galaxies utilizes images of eight PG quasars from the WFPC2 and NICMOS instruments aboard HST. I use narrow-band images centered on the Hβ, [OII]λ3727, [OIII]λ5007, and Paα emission lines to construct extinction and star formation maps. Additionally, I use line-ratio maps to distinguish AGN-powered line emission from star formation powered line emission. I find star formation, albeit at rates are lower than expected, suggesting that quasar host galaxies are dynamically more advanced than suspected. Seven of the galaxies have higher mass-specific star-formation rates. Additionally, I see evidence of shocked gas, supporting the hypotheses from earlier works that AGN activity quenches star formation in host galaxies by disrupting gas reservoirs.

  10. Cosmic strings and galaxy formation

    NASA Technical Reports Server (NTRS)

    Bertschinger, Edmund

    1989-01-01

    The cosmogonical model proposed by Zel'dovich and Vilenkin (1981), in which superconducting cosmic strings act as seeds for the origin of structure in the universe, is discussed, summarizing the results of recent theoretical investigations. Consideration is given to the formation of cosmic strings, the microscopic structure of strings, gravitational effects, cosmic string evolution, and the formation of galaxies and large-scale structure. Simulation results are presented in graphs, and several outstanding issues are listed and briefly characterized.

  11. Star formation in dwarf galaxies

    NASA Astrophysics Data System (ADS)

    Dong, Shawfeng

    In this thesis, we examine the star formation history and stellar feedback effects of dwarf galaxies under the influence of extragalactic ultraviolet radiation, as well as the evolution of residual gas within tidally-limited dwarf galaxies and globular clusters. Previous work has indicated that the background UV flux can easily ionize the gas within typical dwarf galaxies, delaying or even preventing cooling and star formation within them. Many dwarf galaxies within the Local Group are, however, observed to contain multiple generations of stars, the oldest of which formed in the early epochs of cosmic evolution, when the background UV flux was intense. In order to address this paradox, we consider the dynamical evolution of gas in dwarf galaxies using a one-dimensional, spherically symmetric, Lagrangian numerical scheme which also computes the effects of radiative transfer and photoionization. We include in the scheme a physically-motivated star formation recipe and consider the effects of feedback. This scheme allows us to follow the history of the gas and of star formation within dwarf galaxies, as influenced by both external and internal UV radiation. Our results indicate that star formation in the severe environment of dwarf galaxies is a difficult and inefficient process. In potentials with total mass less than a few 106 M⊙ , and velocity dispersion less than a few km s-1 , residual gas is efficiently photoionized by cosmic background UV radiation. For intermediate mass systems, such as the dSphs around the Galaxy, star formation can proceed within early cosmic epochs despite the intense background UV flux. Triggering processes such as merger events, collisions, and tidal disturbance can lead to density enhancements, reducing the recombination timescale, allowing gas to cool and star formation to proceed. However, the star formation and gas retention efficiency may vary widely in galaxies with similar dark matter potentials, because they depend on many

  12. Treating tar sands formations with karsted zones

    SciTech Connect

    Vinegar, Harold J.; Karanikas, John Michael

    2010-03-09

    Methods for treating a tar sands formation are described herein. The tar sands formation may have one or more karsted zones. Methods may include providing heat from one or more heaters to one or more karsted zones of the tar sands formation to mobilize fluids in the formation. At least some of the mobilized fluids may be produced from the formation.

  13. Isolated star formation: from cloud formation to core collapse.

    PubMed

    Ward-Thompson, Derek

    2002-01-01

    The formation of stars is one of the most fundamental problems in astrophysics, as it underlies many other questions, on scales from the formation of galaxies to the formation of the solar system. The physical processes involve the turbulent behavior of a partially ionized medium containing a non-uniform magnetic field. Current debate centers around the time taken for turbulence to decay and the relative importance of the roles played by magnetic fields and turbulence. Technological advances such as millimeter-wave cameras have made possible observations of the temperature and density profiles, and statistical calculations of the lifetimes, of objects collapsing under their own self-gravity and those on the verge of collapse. Increased computing power allows more complex models to be made that include magnetic and turbulent effects. No current model can reproduce all of the observations. PMID:11778038

  14. An Adaptable Seismic Data Format

    NASA Astrophysics Data System (ADS)

    Krischer, Lion; Smith, James; Lei, Wenjie; Lefebvre, Matthieu; Ruan, Youyi; de Andrade, Elliott Sales; Podhorszki, Norbert; Bozdağ, Ebru; Tromp, Jeroen

    2016-11-01

    We present ASDF, the Adaptable Seismic Data Format, a modern and practical data format for all branches of seismology and beyond. The growing volume of freely available data coupled with ever expanding computational power opens avenues to tackle larger and more complex problems. Current bottlenecks include inefficient resource usage and insufficient data organization. Properly scaling a problem requires the resolution of both these challenges, and existing data formats are no longer up to the task. ASDF stores any number of synthetic, processed or unaltered waveforms in a single file. A key improvement compared to existing formats is the inclusion of comprehensive meta information, such as event or station information, in the same file. Additionally, it is also usable for any non-waveform data, for example, cross-correlations, adjoint sources or receiver functions. Last but not least, full provenance information can be stored alongside each item of data, thereby enhancing reproducibility and accountability. Any data set in our proposed format is self-describing and can be readily exchanged with others, facilitating collaboration. The utilization of the HDF5 container format grants efficient and parallel I/O operations, integrated compression algorithms and check sums to guard against data corruption. To not reinvent the wheel and to build upon past developments, we use existing standards like QuakeML, StationXML, W3C PROV and HDF5 wherever feasible. Usability and tool support are crucial for any new format to gain acceptance. We developed mature C/Fortran and Python based APIs coupling ASDF to the widely used SPECFEM3D_GLOBE and ObsPy toolkits.

  15. The Dynamics of Latifundia Formation

    PubMed Central

    Chaves, Luis Fernando

    2013-01-01

    Land tenure inequity is a major social problem in developing nations worldwide. In societies, where land is a commodity, inequities in land tenure are associated with gaps in income distribution, poverty and biodiversity loss. A common pattern of land tenure inequities through the history of civilization has been the formation of latifundia [Zhuāngyuán in chinese], i.e., a pattern where land ownership is concentrated by a small fraction of the whole population. Here, we use simple Markov chain models to study the dynamics of latifundia formation in a heterogeneous landscape where land can transition between forest, agriculture and recovering land. We systematically study the likelihood of latifundia formation under the assumption of pre-capitalist trade, where trade is based on the average utility of land parcels belonging to each individual landowner during a discrete time step. By restricting land trade to that under recovery, we found the likelihood of latifundia formation to increase with the size of the system, i.e., the amount of land and individuals in the society. We found that an increase of the transition rate for land use changes, i.e., how quickly land use changes, promotes more equitable patterns of land ownership. Disease introduction in the system, which reduced land profitability for infected individual landowners, promoted the formation of latifundia, with an increased likelihood for latifundia formation when there were heterogeneities in the susceptibility to infection. Finally, our model suggests that land ownership reforms need to guarantee an equitative distribution of land among individuals in a society to avoid the formation of latifundia. PMID:24376597

  16. The dynamics of latifundia formation.

    PubMed

    Chaves, Luis Fernando

    2013-01-01

    Land tenure inequity is a major social problem in developing nations worldwide. In societies, where land is a commodity, inequities in land tenure are associated with gaps in income distribution, poverty and biodiversity loss. A common pattern of land tenure inequities through the history of civilization has been the formation of latifundia [Zhuāngyuán in chinese], i.e., a pattern where land ownership is concentrated by a small fraction of the whole population. Here, we use simple Markov chain models to study the dynamics of latifundia formation in a heterogeneous landscape where land can transition between forest, agriculture and recovering land. We systematically study the likelihood of latifundia formation under the assumption of pre-capitalist trade, where trade is based on the average utility of land parcels belonging to each individual landowner during a discrete time step. By restricting land trade to that under recovery, we found the likelihood of latifundia formation to increase with the size of the system, i.e., the amount of land and individuals in the society. We found that an increase of the transition rate for land use changes, i.e., how quickly land use changes, promotes more equitable patterns of land ownership. Disease introduction in the system, which reduced land profitability for infected individual landowners, promoted the formation of latifundia, with an increased likelihood for latifundia formation when there were heterogeneities in the susceptibility to infection. Finally, our model suggests that land ownership reforms need to guarantee an equitative distribution of land among individuals in a society to avoid the formation of latifundia. PMID:24376597

  17. The dynamics of latifundia formation.

    PubMed

    Chaves, Luis Fernando

    2013-01-01

    Land tenure inequity is a major social problem in developing nations worldwide. In societies, where land is a commodity, inequities in land tenure are associated with gaps in income distribution, poverty and biodiversity loss. A common pattern of land tenure inequities through the history of civilization has been the formation of latifundia [Zhuāngyuán in chinese], i.e., a pattern where land ownership is concentrated by a small fraction of the whole population. Here, we use simple Markov chain models to study the dynamics of latifundia formation in a heterogeneous landscape where land can transition between forest, agriculture and recovering land. We systematically study the likelihood of latifundia formation under the assumption of pre-capitalist trade, where trade is based on the average utility of land parcels belonging to each individual landowner during a discrete time step. By restricting land trade to that under recovery, we found the likelihood of latifundia formation to increase with the size of the system, i.e., the amount of land and individuals in the society. We found that an increase of the transition rate for land use changes, i.e., how quickly land use changes, promotes more equitable patterns of land ownership. Disease introduction in the system, which reduced land profitability for infected individual landowners, promoted the formation of latifundia, with an increased likelihood for latifundia formation when there were heterogeneities in the susceptibility to infection. Finally, our model suggests that land ownership reforms need to guarantee an equitative distribution of land among individuals in a society to avoid the formation of latifundia.

  18. Modeling of Mitochondrial Donut Formation

    PubMed Central

    Long, Qi; Zhao, Danyun; Fan, Weimin; Yang, Liang; Zhou, Yanshuang; Qi, Juntao; Wang, Xin; Liu, Xingguo

    2015-01-01

    Mitochondria are highly dynamic cell organelles. Continual cycles of fusion and fission play an important role in mitochondrial metabolism and cellular signaling. Previously, a novel mitochondrial morphology, the donut, was reported in cells after hypoxia-reoxygenation or osmotic pressure changes. However, the mechanism of donut formation remained elusive. Here, we obtained the distribution of donut diameters (D = 2R) and found that 95% are >0.8 μm. We also performed highly precise measurements of the mitochondrial tubule diameters using superresolution and electron microscopy. Then, we set up a model by calculating the mitochondrial bending energy and osmotic potential during donut formation. It shows that the bending energy is increased as the radius of curvature, R, gets smaller in the process of donut formation, especially for radii <0.4 μm, creating a barrier to donut formation. The calculations also show that osmotic potential energy release can balance the rising bending energy through volume expansion. Finally, we revealed the donut formation process in a Gibbs free-energy-dependent model combining calculations and measurements. PMID:26331247

  19. Star formation in Galactic flows

    NASA Astrophysics Data System (ADS)

    Smilgys, Romas; Bonnell, Ian A.

    2016-06-01

    We investigate the triggering of star formation in clouds that form in Galactic scale flows as the interstellar medium passes through spiral shocks. We use the Lagrangian nature of smoothed particle hydrodynamics simulations to trace how the star-forming gas is gathered into self-gravitating cores that collapse to form stars. Large-scale flows that arise due to Galactic dynamics create shocks of the order of 30 km s-1 that compress the gas and form dense clouds (n > several × 102 cm-3) in which self-gravity becomes relevant. These large-scale flows are necessary for creating the dense physical conditions for gravitational collapse and star formation. Local gravitational collapse requires densities in excess of n > 103 cm-3 which occur on size scales of ≈1 pc for low-mass star-forming regions (M < 100 M⊙), and up to sizes approaching 10 pc for higher mass regions (M > 103 M⊙). Star formation in the 250 pc region lasts throughout the 5 Myr time-scale of the simulation with a star formation rate of ≈10-1 M⊙ yr-1 kpc-2. In the absence of feedback, the efficiency of the star formation per free-fall time varies from our assumed 100 per cent at our sink accretion radius to values of <10-3 at low densities.

  20. Biofilm Formation by Candida dubliniensis

    PubMed Central

    Ramage, Gordon; Vande Walle, Kacy; Wickes, Brian L.; López-Ribot, José L.

    2001-01-01

    Candida dubliniensis is an opportunistic yeast closely related to Candida albicans that has been recently implicated in oropharyngeal candidiasis in human immunodeficiency virus-infected patients. Most manifestations of candidiasis are associated with biofilm formation, with cells in biofilms displaying properties dramatically different from free-living cells grown under normal laboratory conditions. Here, we report on the development of in vitro models of C. dubliniensis biofilms on the surfaces of biomaterials (polystyrene and acrylic) and on the characteristics associated with biofilm formation by this newly described species. Time course analysis using a formazan salt reduction assay to monitor metabolic activities of cells within the biofilm, together with microscopy studies, revealed that biofilm formation by C. dubliniensis occurred after initial focal adherence, followed by growth, proliferation, and maturation over 24 to 48 h. Serum and saliva preconditioning films enhanced the initial attachment of C. dubliniensis and subsequent biofilm formation. Scanning electron microscopy and confocal scanning laser microscopy were used to further characterize C. dubliniensis biofilms. Mature C. dubliniensis biofilms consisted of a dense network of yeasts cells and hyphal elements embedded within exopolymeric material. C. dubliniensis biofilms displayed spatial heterogeneity and an architecture showing microcolonies with ramifying water channels. Antifungal susceptibility testing demonstrated the increased resistance of sessile C. dubliniensis cells, including the type strain and eight different clinical isolates, against fluconazole and amphotericin B compared to their planktonic counterparts. C. dubliniensis biofilm formation may allow this species to maintain its ecological niche as a commensal and during infection with important clinical repercussions. PMID:11526156

  1. VLBI Data Interchange Format (VDIF)

    NASA Technical Reports Server (NTRS)

    Whitney, Alan; Kettenis, Mark; Phillips, Chris; Sekido, Mamoru

    2010-01-01

    One important outcome of the 7th International e-VLBI Workshop in Shanghai in June 2008 was the creation of a task force to study and recommend a universal VLBI data format that is suitable for both on-the-wire e-VLBI data transfer, as well as direct disk storage. This task force, called the VLBI Data Interchange Format (VDIF) Task Force, is the first part of a two-part effort, the second of which will address standardization of e-VLBI data-transmission-protocols. The formation of the VDIF Task Force was prompted particularly by increased e-VLBI activity and the difficulties encountered when data arrive at a correlator in different formats from various instruments in various parts of the world. The task force created a streaming packetized data format that may be used for real-time and non-realtime e-VLBI, as well as direct disk storage. The data may contain multiple channels of time-sampled data with an arbitrary number of channels, arbitrary #bits/sample up to 32, and real or complex data; data rates in excess of 100 Gbps are supported. Each data packet is completely self-identifying via a short header, and data may be decoded without reference to any external information. The VDIF task force has completed its work, and the VDIF standard was ratified at the 2009 e-VLBI workshop in Madrid.

  2. SW New Mexico Oil Well Formation Tops

    DOE Data Explorer

    Shari Kelley

    2015-10-21

    Rock formation top picks from oil wells from southwestern New Mexico from scout cards and other sources. There are differing formation tops interpretations for some wells, so for those wells duplicate formation top data are presented in this file.

  3. Diagenetic Microcrystalline Opal Varieties from the Monterey Formation, CA: HRTEM Study of Structures and Phase Transformation Mechanisms

    NASA Technical Reports Server (NTRS)

    Cady, Sherry L.; Wenk, H.-R.; DeVincenzi, Don (Technical Monitor)

    1994-01-01

    Microcrystalline opal varieties form as intermediary precipitates during the diagenetic transformation of biogenically precipitated non-crystalline opal (opal-A) to microquartz. With regard to the Monterey Formation of California, X-ray powder diffraction studies have shown that a decrease in the primary d-spacing of opal-CT toward that of cristobalite occurs with increasing diagenesis. The initial timing of opal-CT/quartz formation and the value of the primary opal-CT d-spacing, are influenced by the sediment. lithology. Transmission electron microscopy methods (CTEM/HRTEM) were used to investigate the structure of the diagenetic phases and establish transformation mechanisms between the varieties of microcrystalline opals in charts and porcelanites from the Monterey Formation. HRTEM images revealed that the most common fibrous varieties of microcrystalline opals contain varying amounts of structural disorder. Finite lamellar units of cristobalite-and tridymite-type. layer sequences were found to be randomly stacked in a direction perpendicular to the fiber axis. Disordered and ordered fibers were found to have coprecipitated within the same radial fiber bundles that formed within the matrix of the Most siliceous samples. HRTEM images, which reveal that the fibers within radial and lepispheric fiber bundles branch non-crystallographically, support an earlier proposal that microspheres in chert grow via a spherulitic growth mechanism. A less common variety of opal-CT was found to be characterized by non-parallel (low-angle) stacking sequences that often contain twinned lamellae. Tabular-shaped crystals of orthorhombic tridymite (PO-2) were also identified in the porcelanite samples. A shift in the primary d-spacing of opal-CT has been interpreted as an indication of solid-state ordering g toward a predominantly cristobalite structure, (opal-C). Domains of opal-C were identified as topotactically-oriented overgrowths on discrete Sections of opal-CT fibers and as

  4. Physicochemical regulation of biofilm formation

    PubMed Central

    Renner, Lars D.; Weibel, Douglas B.

    2011-01-01

    This article reviews the physical and chemical constraints of environments on biofilm formation. We provide a perspective on how materials science and engineering can address fundamental questions and unmet technological challenges in this area of microbiology, such as biofilm prevention. Specifically, we discuss three factors that impact the development and organization of bacterial communities. (1) Physical properties of surfaces regulate cell attachment and physiology and affect early stages of biofilm formation. (2) Chemical properties influence the adhesion of cells to surfaces and their development into biofilms and communities. (3) Chemical communication between cells attenuates growth and influences the organization of communities. Mechanisms of spatial and temporal confinement control the dimensions of communities and the diffusion path length for chemical communication between biofilms, which, in turn, influences biofilm phenotypes. Armed with a detailed understanding of biofilm formation, researchers are applying the tools and techniques of materials science and engineering to revolutionize the study and control of bacterial communities growing at interfaces. PMID:22125358

  5. Jet-Induced Star Formation

    SciTech Connect

    van Breugel, W; Fragile, C; Anninos, P; Murray, S

    2003-12-16

    Jets from radio galaxies can have dramatic effects on the medium through which they propagate. We review observational evidence for jet-induced star formation in low ('FR-I') and high ('FR-II') luminosity radio galaxies, at low and high redshifts respectively. We then discuss numerical simulations which are aimed to explain a jet-induced starburst ('Minkowski's Object') in the nearby FR-I type radio galaxy NGC 541. We conclude that jets can induce star formation in moderately dense (10 cm{sup -3}), warm (10{sup 4} K) gas; that this may be more common in the dense environments of forming, active galaxies; and that this may provide a mechanism for 'positive' feedback from AGN in the galaxy formation process.

  6. Bundle Formation in Biomimetic Hydrogels.

    PubMed

    Jaspers, Maarten; Pape, A C H; Voets, Ilja K; Rowan, Alan E; Portale, Giuseppe; Kouwer, Paul H J

    2016-08-01

    Bundling of single polymer chains is a crucial process in the formation of biopolymer network gels that make up the extracellular matrix and the cytoskeleton. This bundled architecture leads to gels with distinctive properties, including a large-pore-size gel formation at very low concentrations and mechanical responsiveness through nonlinear mechanics, properties that are rarely observed in synthetic hydrogels. Using small-angle X-ray scattering (SAXS), we study the bundle formation and hydrogelation process of polyisocyanide gels, a synthetic material that uniquely mimics the structure and mechanics of biogels. We show how the structure of the material changes at the (thermally induced) gelation point and how factors such as concentration and polymer length determine the architecture, and with that, the mechanical properties. The correlation of the gel mechanics and the structural parameters obtained from SAXS experiments is essential in the design of future (synthetic) mimics of biopolymer networks.

  7. Spatial competition and price formation

    NASA Astrophysics Data System (ADS)

    Nagel, Kai; Shubik, Martin; Paczuski, Maya; Bak, Per

    2000-12-01

    We look at price formation in a retail setting, that is, companies set prices, and consumers either accept prices or go someplace else. In contrast to most other models in this context, we use a two-dimensional spatial structure for information transmission, that is, consumers can only learn from nearest neighbors. Many aspects of this can be understood in terms of generalized evolutionary dynamics. In consequence, we first look at spatial competition and cluster formation without price. This leads to establishement size distributions, which we compare to reality. After some theoretical considerations, which at least heuristically explain our simulation results, we finally return to price formation, where we demonstrate that our simple model with nearly no organized planning or rationality on the part of any of the agents indeed leads to an economically plausible price.

  8. Angular momentum and star formation

    NASA Astrophysics Data System (ADS)

    Strittmatter, P. A.

    The present investigation is mainly concerned with the importance of high angular resolution observations in studies of star formation and, in particular, with elucidating the role which angular momentum plays in the process. A brief report is included on recent high angular resolution observations made with the Steward Observatory speckle camera system. A consideration of the angular momentum in interstellar clouds indicates that rotation precludes quasi-spherical contraction. A number of solutions to this angular momentum problem are examined, taking into account questions concerning the help provided by high angular resolution observations for an elucidation of the various possible scenarios of star formation. Technical aspects involved in obtaining suitable data are investigated. It is concluded that high angular resolution observations hold considerable promise for solving at least some of the problems associated with the role of angular momentum in star formation.

  9. Formation dynamics in geostationary ring

    NASA Astrophysics Data System (ADS)

    Spiridonova, Sofya

    2016-08-01

    A relative motion model for a satellite formation composed of two Earth-orbiting spacecraft located in the geostationary ring is developed taking into account major gravitational and non-gravitational forces. A previously existing model featuring perturbation due to J_2 is enhanced by the perturbations due to solar radiation pressure arising from unequal area-to-mass ratios, as well as the secular and long-periodic gravitational perturbations due to the Sun and the Moon. The extended relative motion model is validated using several typical formation geometries against a reference generated by numerical integration of the absolute orbits of the two spacecraft. The results of this work can find application in future on-orbit servicing and formation flying missions in near-geostationary orbit.

  10. Mathematical Models for Somite Formation

    PubMed Central

    Baker, Ruth E.; Schnell, Santiago; Maini, Philip K.

    2009-01-01

    Somitogenesis is the process of division of the anterior–posterior vertebrate embryonic axis into similar morphological units known as somites. These segments generate the prepattern which guides formation of the vertebrae, ribs and other associated features of the body trunk. In this work, we review and discuss a series of mathematical models which account for different stages of somite formation. We begin by presenting current experimental information and mechanisms explaining somite formation, highlighting features which will be included in the models. For each model we outline the mathematical basis, show results of numerical simulations, discuss their successes and shortcomings and avenues for future exploration. We conclude with a brief discussion of the state of modeling in the field and current challenges which need to be overcome in order to further our understanding in this area. PMID:18023728

  11. Granuloma Formation in Pulmonary Sarcoidosis

    PubMed Central

    Broos, Caroline E.; van Nimwegen, Menno; Hoogsteden, Henk C.; Hendriks, Rudi W.; Kool, Mirjam; van den Blink, Bernt

    2013-01-01

    Sarcoidosis is a granulomatous disorder of unknown cause, affecting multiple organs, but mainly the lungs. The exact order of immunological events remains obscure. Reviewing current literature, combined with careful clinical observations, we propose a model for granuloma formation in pulmonary sarcoidosis. A tight collaboration between macrophages, dendritic cells, and lymphocyte subsets, initiates the first steps toward granuloma formation, orchestrated by cytokines and chemokines. In a substantial part of pulmonary sarcoidosis patients, granuloma formation becomes an on-going process, leading to debilitating disease, and sometimes death. The immunological response, determining granuloma sustainment is not well understood. An impaired immunosuppressive function of regulatory T cells has been suggested to contribute to the exaggerated response. Interestingly, therapeutical agents commonly used in sarcoidosis, such as glucocorticosteroids and anti-TNF agents, interfere with granuloma integrity and restore the immune homeostasis in autoimmune disorders. Increasing insight into their mechanisms of action may contribute to the search for new therapeutical targets in pulmonary sarcoidosis. PMID:24339826

  12. An XML portable chart format.

    PubMed Central

    Chueh, H. C.; Raila, W. F.; Berkowicz, D. A.; Barnett, G. O.

    1998-01-01

    The clinical chart remains the fundamental record of outpatient clinical care. As this information migrates to electronic form, there is an opportunity to create standard formats for transmitting these charts. This paper describes work toward a Portable Chart Format (PCF) that can represent the relevant aspects of an outpatient chart. The main goal of the format is to provide a packaging medium for outpatient clinical charts in a transfer of care scenario. A secondary goal is to support the aggregation of comparable clinical data for outcomes analysis. The syntax used for PCF is Extended Markup Language (XML), a W3C standard. The structure of the PCF is based on a clinically relevant view of the data. The data definitions and nomenclature used are based primarily on existing clinical standards. PMID:9929315

  13. Pathophysiology of glioma cyst formation.

    PubMed

    Adn, Mahmoudreza; Saikali, Stephan; Guegan, Yvon; Hamlat, Abderrahmane

    2006-01-01

    Fluid filled cystic cavities are accompaniments of some cerebral gliomas. These tumoural cysts together with peritumoural vasogenic brain oedema add to the morbid effects of the gliomas in terms of mass effect and increased intracranial pressure. Although different mechanisms have been suggested as to the pathogenesis of glioma-associated cysts, it is still unclear why these cysts appear in only a limited number of cerebral gliomas while brain oedema, a probable precursor of glioma cysts, is a usual accompaniment of most gliomas. Here, the authors present a two-hit hypothesis of brain glioma cyst formation. We suggest that after the formation of vasogenic tumoural brain oedema, microvascular phenomena may lead to the formation of microcysts, which might later become confluent and grow to form macroscopic cysts. Progress in the understanding of pathogenesis of cerebral glioma cysts might set targets for treatment of brain edema and glioma cysts.

  14. Pattern formation in multiplex networks

    PubMed Central

    Kouvaris, Nikos E.; Hata, Shigefumi; Guilera, Albert Díaz-

    2015-01-01

    The advances in understanding complex networks have generated increasing interest in dynamical processes occurring on them. Pattern formation in activator-inhibitor systems has been studied in networks, revealing differences from the classical continuous media. Here we study pattern formation in a new framework, namely multiplex networks. These are systems where activator and inhibitor species occupy separate nodes in different layers. Species react across layers but diffuse only within their own layer of distinct network topology. This multiplicity generates heterogeneous patterns with significant differences from those observed in single-layer networks. Remarkably, diffusion-induced instability can occur even if the two species have the same mobility rates; condition which can never destabilize single-layer networks. The instability condition is revealed using perturbation theory and expressed by a combination of degrees in the different layers. Our theory demonstrates that the existence of such topology-driven instabilities is generic in multiplex networks, providing a new mechanism of pattern formation. PMID:26042606

  15. Physicochemical regulation of biofilm formation.

    PubMed

    Renner, Lars D; Weibel, Douglas B

    2011-05-01

    This article reviews the physical and chemical constraints of environments on biofilm formation. We provide a perspective on how materials science and engineering can address fundamental questions and unmet technological challenges in this area of microbiology, such as biofilm prevention. Specifically, we discuss three factors that impact the development and organization of bacterial communities. (1) Physical properties of surfaces regulate cell attachment and physiology and affect early stages of biofilm formation. (2) Chemical properties influence the adhesion of cells to surfaces and their development into biofilms and communities. (3) Chemical communication between cells attenuates growth and influences the organization of communities. Mechanisms of spatial and temporal confinement control the dimensions of communities and the diffusion path length for chemical communication between biofilms, which, in turn, influences biofilm phenotypes. Armed with a detailed understanding of biofilm formation, researchers are applying the tools and techniques of materials science and engineering to revolutionize the study and control of bacterial communities growing at interfaces.

  16. Formation of the first stars.

    PubMed

    Bromm, Volker

    2013-11-01

    Understanding the formation of the first stars is one of the frontier topics in modern astrophysics and cosmology. Their emergence signalled the end of the cosmic dark ages, a few hundred million years after the Big Bang, leading to a fundamental transformation of the early Universe through the production of ionizing photons and the initial enrichment with heavy chemical elements. We here review the state of our knowledge, separating the well understood elements of our emerging picture from those where more work is required. Primordial star formation is unique in that its initial conditions can be directly inferred from the Λ cold dark matter (ΛCDM) model of cosmological structure formation. Combined with gas cooling that is mediated via molecular hydrogen, one can robustly identify the regions of primordial star formation, the so-called minihalos, having total masses of ~10(6) M⊙ and collapsing at redshifts z ≈ 20-30. Within this framework, a number of studies have defined a preliminary standard model, with the main result that the first stars were predominantly massive. This model has recently been modified to include a ubiquitous mode of fragmentation in the protostellar disks, such that the typical outcome of primordial star formation may be the formation of a binary or small multiple stellar system. We will also discuss extensions to this standard picture due to the presence of dynamically significant magnetic fields, of heating from self-annihalating WIMP dark matter, or cosmic rays. We conclude by discussing possible strategies to empirically test our theoretical models. Foremost among them are predictions for the upcoming James Webb space telescope (JWST), to be launched ~2018, and for 'stellar archaeology', which probes the abundance pattern in the oldest, most-metal poor stars in our cosmic neighborhood, thereby constraining the nucleosynthesis inside the first supernovae.

  17. Conductive Anodic Filament (CAF) Formation

    NASA Astrophysics Data System (ADS)

    Caputo, Antonio

    Conductive anodic filament (CAF) is a failure mode in printed wiring boards (PWBs) which occurs under high humidity and high voltage gradient conditions. The filament, a copper salt, grows from anode to cathode along the epoxy-glass interface. Ready and Turbini (2000) identified this copper salt as the Cu 2(OH)3Cl, atacamite compound. This work has investigated the influence of polyethylene glycol (PEG) and polyethylene propylene glycol (PEPG) fluxing agents on the chemical nature of CAF. For coupons processed with PEPG flux, with and without chloride, a copper-chloride containing compound was formed in the polymer matrix. This compound was characterized using x-ray photoelectron spectroscopy (XPS) as CuCl and an electrochemical mechanism for the formation of the chloride-containing CAF has been proposed. For PEG flux, with and without chloride, it has been shown that CAF only formed, but no copper containing compound formed in the matrix. It appears for PEG fluxed coupons, a PEG-Cu-Cl complex forms, binds the available Cu and acts as a barrier to the formation of CuCl in the polymer matrix. Meeker and Lu Valle (1995) have previously proposed that CAF failure is best represented by two competing reactions -- the formation of a copper chloride corrosion compound (now identified as Cu2(OH)3Cl) and the formation of innocuous trapped chlorine compounds. Since no evidence of any trapped chloride compounds has been found, we propose that the formation of CAF is best represented by a single non-reversible reaction. For coupons processed with a high bromide-containing flux, bromide containing CAF was created and characterized using transmission electron microscopy (TEM) to be Cu2(OH)3Br. In addition, a copper-containing compound was formed in the polymer matrix and characterized using XPS as CuBr. An electrochemical mechanism for the formation of bromide-containing CAF has been proposed based on the XPS data.

  18. Formation of the first stars.

    PubMed

    Bromm, Volker

    2013-11-01

    Understanding the formation of the first stars is one of the frontier topics in modern astrophysics and cosmology. Their emergence signalled the end of the cosmic dark ages, a few hundred million years after the Big Bang, leading to a fundamental transformation of the early Universe through the production of ionizing photons and the initial enrichment with heavy chemical elements. We here review the state of our knowledge, separating the well understood elements of our emerging picture from those where more work is required. Primordial star formation is unique in that its initial conditions can be directly inferred from the Λ cold dark matter (ΛCDM) model of cosmological structure formation. Combined with gas cooling that is mediated via molecular hydrogen, one can robustly identify the regions of primordial star formation, the so-called minihalos, having total masses of ~10(6) M⊙ and collapsing at redshifts z ≈ 20-30. Within this framework, a number of studies have defined a preliminary standard model, with the main result that the first stars were predominantly massive. This model has recently been modified to include a ubiquitous mode of fragmentation in the protostellar disks, such that the typical outcome of primordial star formation may be the formation of a binary or small multiple stellar system. We will also discuss extensions to this standard picture due to the presence of dynamically significant magnetic fields, of heating from self-annihalating WIMP dark matter, or cosmic rays. We conclude by discussing possible strategies to empirically test our theoretical models. Foremost among them are predictions for the upcoming James Webb space telescope (JWST), to be launched ~2018, and for 'stellar archaeology', which probes the abundance pattern in the oldest, most-metal poor stars in our cosmic neighborhood, thereby constraining the nucleosynthesis inside the first supernovae. PMID:24168986

  19. Stratigraphic sections of the Phosphoria formation in Wyoming, 1947-48

    USGS Publications Warehouse

    McKelvey, Vincent Ellis; Smith, L.E.; Hoppin, R.A.; Armstrong, F.C.

    1952-01-01

    As part of a comprehensive investigation of the phosphate deposits of the western field begun in 1947, the U. S. Geological Survey has measured and sampled the Permian Phosphoria formation at many localities in Wyoming and adjacent states. Because these data will not be fully synthesized for many years, segments of the data, accompanied by little or no interpretation, will be published as preliminary reports as they are assembled. This report, which contains abstracts of some of the sections measured in western Wyoming (pl. 1), is one of this series. The field and laboratory procedures adopted in these investigations are described rather fully in a companion report (McKelvey and others, 1952a). Many people have taken part in this investigation. R. M. Campbell, R. A. Gulbrandsen, R. A. Harris, D. M. Larrabee, F. W. O'Malley, O. A. Payne, R. S. Sears, R. P. Sheldon, and R. A. Smart participated in the description of the strata and the collection of the samples referred to in this report. D. B. Dimick, H. A. Larsen, and T. K. Rigby assisted in the preparation of exposures and the crushing and splitting of samples in the field. The laboratory preparation of samples for chemical analysis was done in Denver, Colo., under the direction of W. P. Huleatt. Most of the P2O5 and acid-insoluble analyses were made for the Survey by the U. S. Bureau of Mines at the Northwest Electrodevelopment Laboratory, Albany, Oreg., under the direction of S. M. Shelton and M. L. Wright. Most of the Al2O3, Fe2O3, and loss-on-ignition analyses were made by the Trace Elements Section laboratory of the Survey in Washington, D. C., under the direction of J. C. Rabbitt by chemists I. Barlow, A. Caemmerer, J. Greene, F. S. Grimadli, N. Guttag, H. Levine, H. Mela, Jr., and R. G. Milkey, and most of the spectrographic reports were prepared in this laboratory by C. L. Waring. The samples from one locality (Coal Canyon) were analyzed for P2O5, Al2O3, Fe2O3, V2O5, F, loss on ignition, and acid insoluble

  20. Optimal Reconfiguration of Tetrahedral Formations

    NASA Technical Reports Server (NTRS)

    Huntington, Geoffrey; Rao, Anil V.; Hughes, Steven P.

    2004-01-01

    The problem of minimum-fuel formation reconfiguration for the Magnetospheric Multi-Scale (MMS) mission is studied. This reconfiguration trajectory optimization problem can be posed as a nonlinear optimal control problem. In this research, this optimal control problem is solved using a spectral collocation method called the Gauss pseudospectral method. The objective of this research is to provide highly accurate minimum-fuel solutions to the MMS formation reconfiguration problem and to gain insight into the underlying structure of fuel-optimal trajectories.

  1. Star formation and gas supply

    NASA Astrophysics Data System (ADS)

    Catinella, B.

    2016-06-01

    A detailed knowledge of how gas cycles in and around galaxies, and how it depends on galaxy properties such as stellar mass and star formation rate, is crucial to understand galaxy formation and evolution. We take advantage of the most sensitive surveys of cold gas in massive galaxies, GASS and COLD GASS, as well as of the state-of-the-art HI blind survey ALFALFA to investigate how molecular and atomic hydrogen reservoirs vary along and across the main sequence of star-forming galaxies.

  2. Magnetohydrodynamic mechanism for pedestal formation.

    PubMed

    Guazzotto, L; Betti, R

    2011-09-16

    Time-dependent two-dimensional magnetohydrodynamic simulations are carried out for tokamak plasmas with edge poloidal flow. Differently from conventional equilibrium theory, a density pedestal all around the edge is obtained when the poloidal velocity exceeds the poloidal sound speed. The outboard pedestal is induced by the transonic discontinuity, the inboard one by mass redistribution. The density pedestal follows the formation of a highly sheared flow at the transonic surface. These results may be relevant to the L-H transition and pedestal formation in high performance tokamak plasmas.

  3. Star formation and extinct radioactivities

    NASA Technical Reports Server (NTRS)

    Cameron, A. G. W.

    1984-01-01

    An assessment is made of the evidence for the existence of now-extinct radioactivities in primitive solar system material, giving attention to implications for the early stages of sun and solar system formation. The characteristics of possible disturbances in dense molecular clouds which can initiate the formation of cloud cores is discussed, with emphasis on these disturbances able to generate fresh radioactivities. A one-solar mass red giant star on the asymptotic giant branch appears to have been the best candidate to account for the short-lived extinct radioactivities in the early solar system.

  4. Pattern formation in the geosciences

    PubMed Central

    Goehring, Lucas

    2013-01-01

    Pattern formation is a natural property of nonlinear and non-equilibrium dynamical systems. Geophysical examples of such systems span practically all observable length scales, from rhythmic banding of chemical species within a single mineral crystal, to the morphology of cusps and spits along hundreds of kilometres of coastlines. This article briefly introduces the general principles of pattern formation and argues how they can be applied to open problems in the Earth sciences. Particular examples are then discussed, which summarize the contents of the rest of this Theme Issue. PMID:24191107

  5. Star formation and its triggers

    NASA Astrophysics Data System (ADS)

    Combes, F.

    2016-06-01

    The relation between star formation and gas density appears linear for galaxies on the main sequence, and when the molecular gas is considered. However, the star formation efficiency (SFE) defined as the ratio of SFR to gas surface densities, can be much higher when SF is triggered by a dynamical process such as galaxy interaction or mergers, or even secular evolution and cold gas accretion. I review recent work showing how the SFE can vary as a function of morphological type, environment, or redshift. Physical processes able to explain positive and negative feedback from supernovae or AGN are discussed.

  6. Geochemical and stable isotopic data on barren and mineralized drill core in the Devonian Popovich Formation, Screamer sector of the Betze-Post gold deposit, northern Carlin trend, Nevada

    USGS Publications Warehouse

    Christiansen, William D.; Hofstra, Albert H.; Zohar, Pamela B.; Tousignant, Gilles

    2011-01-01

    The Devonian Popovich Formation is the major host for Carlin-type gold deposits in the northern Carlin trend of Nevada. The Popovich is composed of gray to black, thin-bedded, calcareous to dolomitic mudstone and limestone deposited near the carbonate platform margin. Carlin-type gold deposits are Eocene, disseminated, auriferous pyrite deposits characterized by acid leaching, sulfidation, and silicification that are typically hosted in Paleozoic calcareous sedimentary rocks exposed in windows through siliceous sedimentary rocks of the Roberts Mountains allochthon. The Carlin trend currently is the largest gold producer in the United States. The Screamer ore zone is a tabular body on the periphery of the huge Betze-Post gold deposit. Screamer is a good place to study both the original lithogeochemistry of the Popovich Formation and the effects of subsequent alteration and mineralization because it is below the level of supergene oxidation, mostly outside the contact metamorphic aureole of the Jurassic Goldstrike stock, has small, high-grade ore zones along fractures and Jurassic dikes, and has intervening areas with lower grade mineralization and barren rock. In 1997, prior to mining at Screamer, drill core intervals from barren and mineralized Popovich Formation were selected for geochemical and stable isotope analysis. The 332, five-foot core samples analyzed are from five holes separated by as much as 2000 feet (600 meters). The samples extend from the base of the Wispy unit up through the Planar and Soft sediment deformation units into the lower part of the upper Mud unit of the Popovich Formation.

  7. The boundary layer, the land surface, and orographic precipitation: the 2012 ASCII campaign in the Sierra Madre, Wyoming

    NASA Astrophysics Data System (ADS)

    Geerts, B.; Yang, Y.; Miao, Q.; Pokharel, B.; Breed, D. W.; Rasmussen, R.

    2011-12-01

    It remains a puzzle why even rather shallow orographic clouds hugging the terrain are remarkably efficient snowfall producers, at least under typical conditions in the Rocky Mountains in winter. We provide evidence for the importance of both boundary-layer turbulence and surface-induced ice crystal production in the explanation of the efficiency of orographic precipitation. This evidence will be examined more in a field campaign to be conducted in early 2012 in the Sierra Madre in Wyoming, a campaign which will deploy airborne profiling radar and lidar, dual-pol DOW radar, radiosondes, and ground-based snow observations, in the context of ongoing research into the effect of AgI seeding of orographic clouds to enhance snowfall.

  8. Star formation across galactic environments

    NASA Astrophysics Data System (ADS)

    Young, Jason

    I present here parallel investigations of star formation in typical and extreme galaxies. The typical galaxies are selected to be free of active galactic nuclei (AGN), while the extreme galaxies host quasars (the most luminous class of AGN). These two environments are each insightful in their own way; quasars are among the most violent objects in the universe, literally reshaping their host galaxies, while my sample of AGN-free star-forming galaxies ranges from systems larger than the Milky Way to small galaxies which are forming stars at unsustainably high rates. The current paradigm of galaxy formation and evolution suggests that extreme circumstances are key stepping stones in the assembly of galaxies like our Milky Way. To test this paradigm and fully explore its ramifications, this dual approach is needed. My sample of AGN-free galaxies is drawn from the KPNO International Spectroscopic Survey. This Halpha-selected, volume-limited survey was designed to detect star-forming galaxies without a bias toward continuum luminosity. This type of selection ensures that this sample is not biased toward galaxies that are large or nearby. My work studies the KISS galaxies in the mid- and far-infrared using photometry from the IRAC and MIPS instruments aboard the Spitzer Space Telescope. These infrared bands are particularly interesting for star formation studies because the ultraviolet light from young stars is reprocessed into thermal emission in the far-infrared (24mum MIPS) by dust and into vibrational transitions features in the mid-infrared (8.0mum IRAC) by polycyclic aromatic hydrocarbons (PAHs). The work I present here examines the efficiencies of PAH and thermal dust emission as tracers of star-formation rates over a wide range of galactic stellar masses. I find that the efficiency of PAH as a star-formation tracer varies with galactic stellar mass, while thermal dust has a highly variable efficiency that does not systematically depend on galactic stellar mass

  9. What Scanner products are available?

    Atmospheric Science Data Center

    2014-12-08

    ... the ERBE scanner CD which gives all the S4G monthly mean 2.5 degree gridded data from both single satellite and combined-satellite product in ASCII format. Also, ordering the S4G HDF data online and using the ncdump utility to perform a straight ASCII dump is another ...

  10. Data Transfer Capabilities of CD-ROM Software, Part II.

    ERIC Educational Resources Information Center

    Jasco, Peter

    1991-01-01

    Describes and compares several exchange/transfer formats used to upload records into software host programs, including unstructured or plain ASCII; fixed field; delimited ASCII; tagged; MARC (Machine Readable Cataloging); and graphic. It is concluded that CD-ROM producers should strengthen the built-in output management of programs and offer…

  11. SAS FORMATS: USES AND ABUSES

    EPA Science Inventory

    SAS formats are a very powerful tool. They allow you to display the data in a more readable manner without modifying the data. They can also be used to group data into categories for use in various procedures like PROC FREQ, PROC TTEST, and PROC MEANS (as a class variable). ...

  12. Facial Prototype Formation in Children.

    ERIC Educational Resources Information Center

    Inn, Donald; And Others

    This study examined memory representation as it is exhibited in young children's formation of facial prototypes. In the first part of the study, researchers constructed images of faces using an Identikit that provided the features of hair, eyes, mouth, nose, and chin. Images were varied systematically. A series of these images, called exemplar…

  13. Chevrons formation in laminar erosion

    NASA Astrophysics Data System (ADS)

    Devauchelle, Olivier; Josserand, Christophe; Lagree, Pierre-Yves; Zaleski, Stephane; Nguyen, Khanh-Dang; Malverti, Luce; Lajeunesse, Eric

    2007-11-01

    When eroded by laminar free-surface flows, granular substrates may generate a rich variety of natural patterns. Among them are dunes, similar to the ones observed by Charru and Hinch in a Couette cell (Charru F, Hinch EJ ; Ripple formation on a particle bed sheared by a viscous liquid. Part 1. Steady flow ; JOURNAL OF FLUID MECHANICS 550: 111-121 MAR 10 2006). Chevron-shaped instabilities as those found on the sea-shore, can also be observed, sometimes in competition against dunes formation. These were first pointed out by Daerr et al. when pulling a plate covered with granular material out of a bath of water (Daerr A, Lee P, Lanuza J, et al. ; Erosion patterns in a sediment layer ; PHYSICAL REVIEW E 67 (6): Art. No. 065201 Part 2 JUN 2003). Both instabilities can grow in laminar open-channel flows, an experimental set-up which is more easily controlled. The mechanisms leading to the formation of these patterns are investigated and compared. Whereas dunes formation requires vertical inertia effects, we show that chevrons may result from the non-linear evolution of bars instability, which may grow even in purely viscous flows.

  14. Junction formation during desiccation cracking.

    PubMed

    Toga, K B; Alaca, B Erdem

    2006-08-01

    In order to provide a sound physical basis for the understanding of the formation of desiccation crack networks, an experimental study is presented addressing junction formation. Focusing on junctions, basic features of the network determining the final pattern, provides an elemental approach and imparts conceptual clarity to the rather complicated problem of the evolution of crack patterns. Using coffee-water mixtures a clear distinction between junction formation during nucleation and propagation is achieved. It is shown that for the same drying suspension, one can switch from the well-known symmetric triple junctions that are unique to the nucleation phase to propagation junctions that are purely dictated by the variations of the stress state. In the latter case, one can even manipulate the path of a propagating crack in a deterministic fashion by changing the stress state within the suspension. Clear microscopic evidence is provided for the formation of propagation junctions, and material inhomogeneity is observed to be reflected by a broad distribution of angles, in stark contrast to shrinkage cracks in homogeneous solid films.

  15. Formative Assessment in Primary Science

    ERIC Educational Resources Information Center

    Loughland, Tony; Kilpatrick, Laetitia

    2015-01-01

    This action learning study in a year three classroom explored the implementation of five formative assessment principles to assist students' understandings of the scientific topic of liquids and solids. These principles were employed to give students a greater opportunity to express their understanding of the concepts. The study found that…

  16. Laser-assisted antihydrogen formation

    SciTech Connect

    Chattopadhyay, A.; Sinha, C.

    2006-08-15

    Laser-assisted antihydrogen (H) formation cross sections (differential and total) for collisions of antiprotons with positronium (Ps) are studied in the framework of the eikonal approximation for two geometries, when the field polarization is parallel (parallel{sup L}) or perpendicular (perpendicular{sup r}) to the incident Ps momentum. The variations of the H formation cross sections with respect to the field strength and the laser photon energy are studied for the multiphoton (absorption and emission) processes. The contribution of the atomic (both Ps and H) dressing terms to the enhancement of the H formation cross section is studied for both the geometries (parallel{sup L} and (perpendicular{sup r}). The most important prediction from the present work is the enhancement of the field-free (FF) H formation cross sections particularly at lower incident energies when the system (Ps+p) is irradiated by a single mode, linearly polarized laser, the enhancement being more pronounced for a wider range of incident energy in the perpendicular{sup r} geometry than in the parallel{sup L} one.

  17. Pattern Formation in Convective Instabilities

    NASA Astrophysics Data System (ADS)

    Friedrich, R.; Bestehorn, M.; Haken, H.

    The present article reviews recent progress in the study of pattern formation in convective instabilities. After a brief discussion of the relevant basic hydrodynamic equations as well as a short outline of the mathematical treatment of pattern formation in complex systems the self-organization of spatial and spatio-temporal structures due to convective instabilities is considered. The formation of various forms of convective patterns arising in the Bénard experiment, i.e. in a horizontal fluid layer heated from below, is discussed. Then the review considers pattern formation in the Bénard instability in spherical geometries. In that case it can be demonstrated how the interaction among several convective cells may lead to time dependent as well as chaotic evolution of the spatial structures. Finally, the convective instability in a binary fluid mixture is discussed. In contrast to the instability in a single component fluid the instability may be oscillatory. In that case convection sets in in the form of travelling wave patterns which in addition to a complicated and chaotic temporal behaviour exhibit more or less spatial irregularity already close to threshold.

  18. Formative Assessment in Dance Education

    ERIC Educational Resources Information Center

    Andrade, Heidi; Lui, Angela; Palma, Maria; Hefferen, Joanna

    2015-01-01

    Feedback is crucial to students' growth as dancers. When used within the framework of formative assessment, or assessment for learning, feedback results in actionable next steps that dancers can use to improve their performances. This article showcases the work of two dance specialists, one elementary and one middle school teacher, who have…

  19. A standard audit trail format

    SciTech Connect

    Bishop, M.

    1995-02-01

    The central role of audit trails, or (more properly) logs, in security monitoring needs little description, for it is too well known for any to doubt it. Auditing, or the analysis of logs, is a central part of security not only in computer system security but also in analyzing financial and other non-technical systems. As part of this process, it is often necessary to reconcile logs from different sources. This speaks of a need for a standard logging format. A standard log format robust enough to meet the needs of heterogeneity, transportability across various network protocols, and flexibility sufficient to meet a variety of needs in very different environments must satisfy two basic properties: extensibility and portability. This report presents the author`s proposed format for a standard log record. In section 3, he shows how and where the translation should be done, and in section 4 he demonstrates how log records from several disparate systems would be put into this format. Section 5 concludes with some observations and suggestions for future work.

  20. Stereotype Formation: Biased by Association

    ERIC Educational Resources Information Center

    Le Pelley, Mike E.; Reimers, Stian J.; Calvini, Guglielmo; Spears, Russell; Beesley, Tom; Murphy, Robin A.

    2010-01-01

    We propose that biases in attitude and stereotype formation might arise as a result of learned differences in the extent to which social groups have previously been predictive of behavioral or physical properties. Experiments 1 and 2 demonstrate that differences in the experienced predictiveness of groups with respect to evaluatively neutral…

  1. The EPRDATA Format: A Dialogue

    SciTech Connect

    Hughes, III, Henry Grady

    2015-08-18

    Recently the Los Alamos Nuclear Data Team has communicated certain issues of concern in relation to the new electron/photon/relaxation ACE data format as released in the eprdata12 library. In this document those issues are parsed, analyzed, and answered.

  2. Formative Assessment: A Cybernetic Viewpoint

    ERIC Educational Resources Information Center

    Roos, Bertil; Hamilton, David

    2005-01-01

    This paper considers alternative assessment, feedback and cybernetics. For more than 30 years, debates about the bi-polarity of formative and summative assessment have served as surrogates for discussions about the workings of the mind, the social implications of assessment and, as important, the role of instruction in the advancement of learning.…

  3. Technology Enhanced Distributive Formative Evaluation

    ERIC Educational Resources Information Center

    Moore, David Richard

    2008-01-01

    Quality assurance in instructional development demands an exhaustive formative evaluation effort and applied testing. Unfortunately, this process is expensive and requires large numbers of user testers with characteristics similar to the intended audience. This article presents a procedure for increasing the efficiency of quality assurance efforts…

  4. Multiple cilia suppress tumour formation.

    PubMed

    Eberhart, Charles

    2016-04-01

    Primary cilia are cellular structures that have important functions in development and disease. The suppression of multiciliate differentiation of choroid plexus precursors, and maintenance of a single primary cilium by Notch1, is now shown to be involved in choroid plexus tumour formation. PMID:27027488

  5. Formative Considerations Using Integrative CALL.

    ERIC Educational Resources Information Center

    Callahan, Philip; Shaver, Peter

    2001-01-01

    Addresses technical and learning issues relating to a formative implementation of a computer assisted language learning (CALL) browser-based intermediate Russian program. Instruction took place through a distance education implementation and in a grouped classroom using a local-area network. Learners indicated the software was clear, motivating,…

  6. Audiences for Contemporary Radio Formats.

    ERIC Educational Resources Information Center

    Lull, James T.; And Others

    A radio audience survey of 110 sample geographic clusters in the Santa Barbara, California, area served a twofold purpose: the construction of a demographic profile of audience types according to radio format choices, and the identification and analysis of various audience subgroups. A skip interval technique of these geographic clusters resulted…

  7. Constraints on galaxy formation theories

    NASA Technical Reports Server (NTRS)

    Szalay, A. S.

    1986-01-01

    The present theories of galaxy formation are reviewed. The relation between peculiar velocities, temperature fluctuations of the microwave background and the correlation function of galaxies point to the possibility that galaxies do not form uniformly everywhere. The velocity data provide strong constraints on the theories even in the case when light does not follow mass of the universe.

  8. Amyloid Beta Mediates Memory Formation

    ERIC Educational Resources Information Center

    Garcia-Osta, Ana; Alberini, Cristina M.

    2009-01-01

    The amyloid precursor protein (APP) undergoes sequential cleavages to generate various polypeptides, including the amyloid [beta] (1-42) peptide (A[beta][1-42]), which is believed to play a major role in amyloid plaque formation in Alzheimer's disease (AD). Here we provide evidence that, in contrast with its pathological role when accumulated,…

  9. Mantle dynamics following supercontinent formation

    NASA Astrophysics Data System (ADS)

    Heron, Philip J.

    This thesis presents mantle convection numerical simulations of supercontinent formation. Approximately 300 million years ago, through the large-scale subduction of oceanic sea floor, continental material amalgamated to form the supercontinent Pangea. For 100 million years after its formation, Pangea remained relatively stationary, and subduction of oceanic material featured on its margins. The present-day location of the continents is due to the rifting apart of Pangea, with supercontinent dispersal being characterized by increased volcanic activity linked to the generation of deep mantle plumes. The work presented here investigates the thermal evolution of mantle dynamics (e.g., mantle temperatures and sub-continental plumes) following the formation of a supercontinent. Specifically, continental insulation and continental margin subduction are analyzed. Continental material, as compared to oceanic material, inhibits heat flow from the mantle. Previous numerical simulations have shown that the formation of a stationary supercontinent would elevate sub-continental mantle temperatures due to the effect of continental insulation, leading to the break-up of the continent. By modelling a vigorously convecting mantle that features thermally and mechanically distinct continental and oceanic plates, this study shows the effect of continental insulation on the mantle to be minimal. However, the formation of a supercontinent results in sub-continental plume formation due to the re-positioning of subduction zones to the margins of the continent. Accordingly, it is demonstrated that continental insulation is not a significant factor in producing sub-supercontinent plumes but that subduction patterns control the location and timing of upwelling formation. A theme throughout the thesis is an inquiry into why geodynamic studies would produce different results. Mantle viscosity, Rayleigh number, continental size, continental insulation, and oceanic plate boundary evolution are

  10. Sedimentary pyrite formation: An update

    NASA Astrophysics Data System (ADS)

    Berner, Robert A.

    1984-04-01

    Sedimentary pyrite formation during early diagenesis is a major process for controlling the oxygen level of the atmosphere and the sulfate concentration in seawater over geologic time. The amount of pyrite that may form in a sediment is limited by the rates of supply of decomposable organic matter, dissolved sulfate, and reactive detrital iron minerals. Organic matter appears to be the major control on pyrite formation in normal (non-euxinic) terrigenous marine sediments where dissolved sulfate and iron minerals are abundant. By contrast, pyrite formation in non-marine, freshwater sediments is severely limited by low concentrations of sulfate and this characteristic can be used to distinguish ancient organic-rich fresh water shales from marine shales. Under marine euxinic conditions sufficient H 2S is produced that the dominant control on pyrite formation is the availability of reactive iron minerals. Calculations, based on a sulfur isotope model, indicate that over Phanerozoic time the worldwide average organic carbon-to-pyrite sulfur ratio of sedimentary rocks has varied considerably. High C/S ratios during Permo-Carboniferous time can be explained by a shift of major organic deposition from the oceans to the land which resulted in the formation of vast coal swamps at that time. Low C/S ratios, compared to today, during the early Paleozoic can be explained in terms of a greater abundance of euxinic basins combined with deposition of a more reactive type of organic matter in the remaining oxygenated portions of the ocean. The latter could have been due to lower oceanic oxygen levels and/or a lack of transportation of refractory terrestrial organic matter to the marine environment due to the absence of vascular land plants at that time.

  11. The Black Hole Formation Probability

    NASA Astrophysics Data System (ADS)

    Clausen, Drew R.; Piro, Anthony; Ott, Christian D.

    2015-01-01

    A longstanding question in stellar evolution is which massive stars produce black holes (BHs) rather than neutron stars (NSs) upon death. It has been common practice to assume that a given zero-age main sequence (ZAMS) mass star (and perhaps a given metallicity) simply produces either an NS or a BH, but this fails to account for a myriad of other variables that may effect this outcome, such as spin, binarity, or even stochastic differences in the stellar structure near core collapse. We argue that instead a probabilistic description of NS versus BH formation may be better suited to account for the current uncertainties in understanding how massive stars die. Using the observed BH mass distribution from Galactic X-ray binaries, we investigate the probability that a star will make a BH as a function of its ZAMS mass. Although the shape of the black hole formation probability function is poorly constrained by current measurements, we believe that this framework is an important new step toward better understanding BH formation. We also consider some of the implications of this probability distribution, from its impact on the chemical enrichment from massive stars, to its connection with the structure of the core at the time of collapse, to the birth kicks that black holes receive. A probabilistic description of BH formation will be a useful input for future population synthesis studies that are interested in the formation of X-ray binaries, the nature and event rate of gravitational wave sources, and answering questions about chemical enrichment.

  12. Inside-Out Planet Formation

    NASA Astrophysics Data System (ADS)

    Tan, Jonathan; Chatterjee, Sourav

    2013-07-01

    The compact multi-transiting planet systems discovered by Kepler challenge planet formation theory. Formation in situ from disks with radial mass surface density profiles similar to the minimum mass solar nebula (MMSN) but boosted in normalization by factors >10 has been suggested. We propose that a more natural way to create these planets in the inner disk is formation sequentially from the inside-out via creation of successive gravitationally unstable rings fed from a continuous stream of small (~cm-m size) "pebbles", drifting inwards via gas drag. Pebbles collect at the pressure maximum associated with the transition from a magneto-rotational instability (MRI)-inactive ("dead zone") region to an inner MRI-active zone. A pebble ring builds up until it either becomes gravitationally unstable to form an ~1-10M_Earth planet directly or induces gradual planet formation via core accretion. The planet may undergo Type I migration into the active region, allowing a new pebble ring and planet to form behind it. Alternatively if migration is inefficient, the planet may continue to accrete from the disk until it becomes massive enough to isolate itself from the accretion flow. A variety of densities may result depending on the relative importance of residual gas accretion as the planet approaches its isolation mass. The process can repeat with a new pebble ring gathering at the new pressure maximum associated with the retreating dead zone boundary. Our simple theoretical model for this scenario of inside-out planet formation yields planetary masses, relative mass scalings with orbital radius, and minimum orbital separations consistent with those seen by Kepler. It provides an explanation of how massive planets can form with tightly-packed system architectures, starting from typical protoplanetary disk properties.

  13. Inside-out Planet Formation

    NASA Astrophysics Data System (ADS)

    Chatterjee, Sourav; Tan, Jonathan C.

    2014-01-01

    The compact multi-transiting planet systems discovered by Kepler challenge planet formation theories. Formation in situ from disks with radial mass surface density, Σ, profiles similar to the minimum mass solar nebula but boosted in normalization by factors >~ 10 has been suggested. We propose that a more natural way to create these planets in the inner disk is formation sequentially from the inside-out via creation of successive gravitationally unstable rings fed from a continuous stream of small (~cm-m size) "pebbles," drifting inward via gas drag. Pebbles collect at the pressure maximum associated with the transition from a magnetorotational instability (MRI)-inactive ("dead zone") region to an inner MRI-active zone. A pebble ring builds up until it either becomes gravitationally unstable to form an ~1 M ⊕ planet directly or induces gradual planet formation via core accretion. The planet may undergo Type I migration into the active region, allowing a new pebble ring and planet to form behind it. Alternatively, if migration is inefficient, the planet may continue to accrete from the disk until it becomes massive enough to isolate itself from the accretion flow. A variety of densities may result depending on the relative importance of residual gas accretion as the planet approaches its isolation mass. The process can repeat with a new pebble ring gathering at the new pressure maximum associated with the retreating dead-zone boundary. Our simple analytical model for this scenario of inside-out planet formation yields planetary masses, relative mass scalings with orbital radius, and minimum orbital separations consistent with those seen by Kepler. It provides an explanation of how massive planets can form with tightly packed and well-aligned system architectures, starting from typical protoplanetary disk properties.

  14. Inside-out planet formation

    SciTech Connect

    Chatterjee, Sourav; Tan, Jonathan C. E-mail: jt@astro.ufl.edu

    2014-01-01

    The compact multi-transiting planet systems discovered by Kepler challenge planet formation theories. Formation in situ from disks with radial mass surface density, Σ, profiles similar to the minimum mass solar nebula but boosted in normalization by factors ≳ 10 has been suggested. We propose that a more natural way to create these planets in the inner disk is formation sequentially from the inside-out via creation of successive gravitationally unstable rings fed from a continuous stream of small (∼cm-m size) 'pebbles', drifting inward via gas drag. Pebbles collect at the pressure maximum associated with the transition from a magnetorotational instability (MRI)-inactive ('dead zone') region to an inner MRI-active zone. A pebble ring builds up until it either becomes gravitationally unstable to form an ∼1 M {sub ⊕} planet directly or induces gradual planet formation via core accretion. The planet may undergo Type I migration into the active region, allowing a new pebble ring and planet to form behind it. Alternatively, if migration is inefficient, the planet may continue to accrete from the disk until it becomes massive enough to isolate itself from the accretion flow. A variety of densities may result depending on the relative importance of residual gas accretion as the planet approaches its isolation mass. The process can repeat with a new pebble ring gathering at the new pressure maximum associated with the retreating dead-zone boundary. Our simple analytical model for this scenario of inside-out planet formation yields planetary masses, relative mass scalings with orbital radius, and minimum orbital separations consistent with those seen by Kepler. It provides an explanation of how massive planets can form with tightly packed and well-aligned system architectures, starting from typical protoplanetary disk properties.

  15. Wintertime Haze Formation in Beijing

    NASA Astrophysics Data System (ADS)

    Levy Zamora, M. E.

    2015-12-01

    Recent severe haze events in China have attracted significant public attention due to the severely reduced visibility and unprecedentedly high pollutant concentrations. Particular attention has been given to the high concentrations of particulate matter with a diameter less than 2.5 microns (PM2.5), which can exceed several hundred micrograms per cubic meter over several days. During January and February of 2015, a suite of aerosol instruments was deployed in Beijing to directly measure a comprehensive set of aerosol properties, including the particle size distribution, effective density, and chemical composition. In this presentation, we will discuss the particulate matter formation mechanisms, the evolution of aerosol properties throughout the event, and how the winter formation mechanisms compare with the warmer seasons. We show that the periodic cycles of severe haze episodes in Beijing are largely driven by meteorological conditions. During haze events, stagnation typically develops as a result of a low planetary boundary layer and weak southerly wind from polluted industrial source regions. Stronger northerly winds were frequently observed during the clean period, which carry unpolluted air masses from the less populated northern mountainous areas. Nucleation consistently occurs on clean days, producing a high number concentration of nano particles. The particle mass concentration exceeding several hundred micrograms per cubic meter is attributed to the continuous size growth from the nucleation-mode particles (diameter less than 10 nm) over multiple days to produce a high concentration of larger particles (diameter greater than 100 nm). The particle chemical composition in Beijing is similar to those commonly measured in other urban centers, which is indicative of chemical constituents dominated by secondary aerosol formation. Our results reveal that the severe haze formation in Beijing during the wintertime is similar to the mechanism of haze formation

  16. Inside-Out Planet Formation

    NASA Astrophysics Data System (ADS)

    Tan, Jonathan Charles; Chatterjee, Sourav; Hu, Xiao; Zhu, Zhaohuan; Mohanty, Subhanjoy

    2015-08-01

    The Kepler-discovered systems with tightly-packed inner planets (STIPs), typically with several planets of Earth to super-Earth masses on well-aligned, sub-AU orbits may host the most common type of planets in the Galaxy. They pose a great challenge for planet formation theories, which fall into two broad classes: (1) formation further out followed by migration; (2) formation in situ from a disk of gas and planetesimals. I review the pros and cons of these classes, before focusing on a new theory of sequential in situ formation from the inside-out via creation of successive gravitationally unstable rings fed from a continuous stream of small (~cm-m size) "pebbles," drifting inward via gas drag. Pebbles first collect at the pressure trap associated with the transition from a magnetorotational instability (MRI)-inactive ("dead zone") region to an inner MRI-active zone. A pebble ring builds up until it either becomes gravitationally unstable to form an Earth to super-Earth-mass planet directly or induces gradual planet formation via core accretion. The planet continues to accrete until it becomes massive enough to isolate itself from the accretion flow via gap opening. The process repeats with a new pebble ring gathering at the new pressure maximum associated with the retreating dead-zone boundary. I discuss the theory’s predictions for planetary masses, relative mass scalings with orbital radius, and minimum orbital separations, and their comparison with observed systems. Finally I speculate about potential causes of diversity of planetary system architectures, i.e., STIPs versus Solar System analogs.

  17. What Is Formation? A Conceptual Discussion

    ERIC Educational Resources Information Center

    Sutphen, Molly; de Lange, Thomas

    2015-01-01

    This paper addresses the principles and connotations of the term "formation." In our discussion of formation, we draw on different disciplines in order to widen and deepen our understanding of the concept of formation. We also mirror the formation concept against comparable terms and draw on studies in which it has been applied in…

  18. 40 CFR 1502.10 - Recommended format.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 33 2011-07-01 2011-07-01 false Recommended format. 1502.10 Section... § 1502.10 Recommended format. Agencies shall use a format for environmental impact statements which will... following standard format for environmental impact statements should be followed unless the...

  19. Standard Formats for Atomic Data: the APED

    SciTech Connect

    Smith, R K; Brickhouse, N S; Liedahl, D A; Raymond, J C

    2001-06-05

    Standardized formats for atomic data used in calculating emission from a collisionally-ionized plasma are described. The formats use the astronomical-standard FITS format, and are extendible to other purposes, such as photoionization data. The formats emphasize storing references to the original data source and keeping the data in as-received form, to aid in checking against the original literature.

  20. 40 CFR 1502.10 - Recommended format.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Recommended format. 1502.10 Section... § 1502.10 Recommended format. Agencies shall use a format for environmental impact statements which will... following standard format for environmental impact statements should be followed unless the...

  1. 40 CFR 1502.10 - Recommended format.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Recommended format. 1502.10 Section... § 1502.10 Recommended format. Agencies shall use a format for environmental impact statements which will... following standard format for environmental impact statements should be followed unless the...

  2. Method of fracturing a geological formation

    DOEpatents

    Johnson, James O.

    1990-01-01

    An improved method of fracturing a geological formation surrounding a well bore is disclosed. A relatively small explosive charge is emplaced in a well bore and the bore is subsequently hydraulically pressurized to a pressure less than the formation breakdown pressure and preferably greater than the fracture propagation pressure of the formation. The charge is denoted while the bore is so pressurized, resulting in the formation of multiple fractures in the surrounding formation with little or no accompanying formation damage. Subsequent hydraulic pressurization can be used to propagate and extend the fractures in a conventional manner. The method is useful for stimulating production of oil, gas and possibly water from suitable geologic formations.

  3. ASDF: A new data format for astronomy

    NASA Astrophysics Data System (ADS)

    Greenfield, P.; Droettboom, M.; Bray, E.

    2015-09-01

    We present the case for developing a successor format for the immensely successful FITS format. We first review existing alternative formats and discuss why we do not believe they provide an adequate solution. The proposed format is called the Advanced Scientific Data Format (ASDF) and is based on an existing text format, YAML, that we believe removes most of the current problems with the FITS format. An overview of the capabilities of the new format is given along with specific examples. This format has the advantage that it does not limit the size of attribute names (akin to FITS keyword names) nor place restrictions on the size or type of values attributes have. Hierarchical relationships are explicit in the syntax and require no special conventions. Finally, it is capable of storing binary data within the file in its binary form. At its basic level, the format proposed has much greater applicability than for just astronomical data.

  4. Treating tar sands formations with dolomite

    DOEpatents

    Vinegar, Harold J.; Karanikas, John Michael

    2010-06-08

    Methods for treating a tar sands formation are described herein. The tar sands formation may include dolomite and hydrocarbons. Methods may include providing heat at less than the decomposition temperature of dolomite from one or more heaters to at least a portion of the formation. At least some of the hydrocarbon fluids are mobilized in the formation. At least some of the hydrocarbon fluids may be produced from the formation.

  5. Engineering biofilm formation and dispersal

    PubMed Central

    Wood, Thomas K.; Hong, Seok Hoon; Ma, Qun

    2011-01-01

    Anywhere water is in the liquid state, bacteria will exist as biofilms, which are complex communities of cells cemented together. Although frequently associated with disease and biofouling, biofilms are also important for engineering applications, such as bioremediation, biocatalysis and microbial fuel cells. Here we review approaches to alter genetic circuits and cell signaling toward controlling biofilm formation, and emphasize utilizing these tools for engineering applications. Based on a better understanding of the genetic basis of biofilm formation, we find that biofilms may be controlled by manipulating extracellular signals and that they may be dispersed using conserved intracellular signals and regulators. Biofilms could also be formed at specific locations where they might be engineered to make chemicals or treat human disease. PMID:21131080

  6. Rapid gas hydrate formation process

    DOEpatents

    Brown, Thomas D.; Taylor, Charles E.; Unione, Alfred J.

    2013-01-15

    The disclosure provides a method and apparatus for forming gas hydrates from a two-phase mixture of water and a hydrate forming gas. The two-phase mixture is created in a mixing zone which may be wholly included within the body of a spray nozzle. The two-phase mixture is subsequently sprayed into a reaction zone, where the reaction zone is under pressure and temperature conditions suitable for formation of the gas hydrate. The reaction zone pressure is less than the mixing zone pressure so that expansion of the hydrate-forming gas in the mixture provides a degree of cooling by the Joule-Thompson effect and provides more intimate mixing between the water and the hydrate-forming gas. The result of the process is the formation of gas hydrates continuously and with a greatly reduced induction time. An apparatus for conduct of the method is further provided.

  7. Laser beam pulse formatting method

    DOEpatents

    Daly, T.P.; Moses, E.I.; Patterson, R.W.; Sawicki, R.H.

    1994-08-09

    A method for formatting a laser beam pulse using one or more delay loops is disclosed. The delay loops have a partially reflective beam splitter and a plurality of highly reflective mirrors arranged such that the laser beam pulse enters into the delay loop through the beam splitter and circulates therein along a delay loop length defined by the mirrors. As the laser beam pulse circulates within the delay loop a portion thereof is emitted upon each completed circuit when the laser beam pulse strikes the beam splitter. The laser beam pulse is thereby formatted into a plurality of sub-pulses. The delay loops are used in combination to produce complex waveforms by combining the sub-pulses using additive waveform synthesis. 8 figs.

  8. Laser beam pulse formatting method

    DOEpatents

    Daly, Thomas P.; Moses, Edward I.; Patterson, Ralph W.; Sawicki, Richard H.

    1994-01-01

    A method for formatting a laser beam pulse (20) using one or more delay loops (10). The delay loops (10) have a partially reflective beam splitter (12) and a plurality of highly reflective mirrors (14) arranged such that the laser beam pulse (20) enters into the delay loop (10) through the beam splitter (12) and circulates therein along a delay loop length (24) defined by the mirrors (14). As the laser beam pulse (20) circulates within the delay loop (10) a portion thereof is emitted upon each completed circuit when the laser beam pulse (20) strikes the beam splitter (12). The laser beam pulse (20) is thereby formatted into a plurality of sub-pulses (50, 52, 54 and 56). The delay loops (10) are used in combination to produce complex waveforms by combining the sub-pulses (50, 52, 54 and 56) using additive waveform synthesis.

  9. Formation of Ultracold Polar Molecules

    NASA Astrophysics Data System (ADS)

    Taylor-Juarros, E.; Côté, R.; Kirby, K.

    2002-05-01

    A variety of experimental techniques have been employed to create a number of ultracold molecules, including CaH, Na_2, K_2, Cs_2, Rb2 and CO. Novel effects are predicted to occur in samples of ultracold polar molecules.(L. Santos et al.), Phys. Rev. Lett. 85, 1791 (2000). We present calculations of the formation rate of ultracold hydrides (LiH, NaH, KH, RbH, and CsH), using the most accurate molecular potentials and dipole moments available. We show that these polar molecules can be produced in selected vibrational and rotational states by stimulated radiative association in a mixture of ultracold hydrogen and alkali metal atoms. We study the properties of these atomic mixtures as well as those of the hydrides, and explore the effect of shape resonances on the formation rates. [2ex] *Supported by NSF

  10. Formation of quasiparallel Alfven solitons

    NASA Technical Reports Server (NTRS)

    Hamilton, R. L.; Kennel, C. F.; Mjolhus, E.

    1992-01-01

    The formation of quasi-parallel Alfven solitons is investigated through the inverse scattering transformation (IST) for the derivative nonlinear Schroedinger (DNLS) equation. The DNLS has a rich complement of soliton solutions consisting of a two-parameter soliton family and a one-parameter bright/dark soliton family. In this paper, the physical roles and origins of these soliton families are inferred through an analytic study of the scattering data generated by the IST for a set of initial profiles. The DNLS equation has as limiting forms the nonlinear Schroedinger (NLS), Korteweg-de-Vries (KdV) and modified Korteweg-de-Vries (MKdV) equations. Each of these limits is briefly reviewed in the physical context of quasi-parallel Alfven waves. The existence of these limiting forms serves as a natural framework for discussing the formation of Alfven solitons.

  11. The dynamics of city formation*

    PubMed Central

    Henderson, J. Vernon; Venables, Anthony J.

    2013-01-01

    This paper examines city formation in a country whose urban population is growing steadily over time, with new cities required to accommodate this growth. In contrast to most of the literature there is immobility of housing and urban infrastructure, and investment in these assets is taken on the basis of forward-looking behavior. In the presence of these fixed assets cities form sequentially, without the population swings in existing cities that arise in current models, but with swings in house rents. Equilibrium city size, absent government, may be larger or smaller than is efficient, depending on how urban externalities vary with population. Efficient formation of cities with internalization of externalities involves local government intervention and borrowing to finance development. The paper explores the institutions required for successful local government intervention. PMID:25089087

  12. Hydrogen Sulfide Inhibits Amyloid Formation

    PubMed Central

    2015-01-01

    Amyloid fibrils are large aggregates of misfolded proteins, which are often associated with various neurodegenerative diseases such as Alzheimer’s, Parkinson’s, Huntington’s, and vascular dementia. The amount of hydrogen sulfide (H2S) is known to be significantly reduced in the brain tissue of people diagnosed with Alzheimer’s disease relative to that of healthy individuals. These findings prompted us to investigate the effects of H2S on the formation of amyloids in vitro using a model fibrillogenic protein hen egg white lysozyme (HEWL). HEWL forms typical β-sheet rich fibrils during the course of 70 min at low pH and high temperatures. The addition of H2S completely inhibits the formation of β-sheet and amyloid fibrils, as revealed by deep UV resonance Raman (DUVRR) spectroscopy and ThT fluorescence. Nonresonance Raman spectroscopy shows that disulfide bonds undergo significant rearrangements in the presence of H2S. Raman bands corresponding to disulfide (RSSR) vibrational modes in the 550–500 cm–1 spectral range decrease in intensity and are accompanied by the appearance of a new 490 cm–1 band assigned to the trisulfide group (RSSSR) based on the comparison with model compounds. The formation of RSSSR was proven further using a reaction with TCEP reduction agent and LC-MS analysis of the products. Intrinsic tryptophan fluorescence study shows a strong denaturation of HEWL containing trisulfide bonds. The presented evidence indicates that H2S causes the formation of trisulfide bridges, which destabilizes HEWL structure, preventing protein fibrillation. As a result, small spherical aggregates of unordered protein form, which exhibit no cytotoxicity by contrast with HEWL fibrils. PMID:25545790

  13. THE BLACK HOLE FORMATION PROBABILITY

    SciTech Connect

    Clausen, Drew; Piro, Anthony L.; Ott, Christian D.

    2015-02-01

    A longstanding question in stellar evolution is which massive stars produce black holes (BHs) rather than neutron stars (NSs) upon death. It has been common practice to assume that a given zero-age main sequence (ZAMS) mass star (and perhaps a given metallicity) simply produces either an NS or a BH, but this fails to account for a myriad of other variables that may effect this outcome, such as spin, binarity, or even stochastic differences in the stellar structure near core collapse. We argue that instead a probabilistic description of NS versus BH formation may be better suited to account for the current uncertainties in understanding how massive stars die. We present an initial exploration of the probability that a star will make a BH as a function of its ZAMS mass, P {sub BH}(M {sub ZAMS}). Although we find that it is difficult to derive a unique P {sub BH}(M {sub ZAMS}) using current measurements of both the BH mass distribution and the degree of chemical enrichment by massive stars, we demonstrate how P {sub BH}(M {sub ZAMS}) changes with these various observational and theoretical uncertainties. We anticipate that future studies of Galactic BHs and theoretical studies of core collapse will refine P {sub BH}(M {sub ZAMS}) and argue that this framework is an important new step toward better understanding BH formation. A probabilistic description of BH formation will be useful as input for future population synthesis studies that are interested in the formation of X-ray binaries, the nature and event rate of gravitational wave sources, and answering questions about chemical enrichment.

  14. The Black Hole Formation Probability

    NASA Astrophysics Data System (ADS)

    Clausen, Drew; Piro, Anthony L.; Ott, Christian D.

    2015-02-01

    A longstanding question in stellar evolution is which massive stars produce black holes (BHs) rather than neutron stars (NSs) upon death. It has been common practice to assume that a given zero-age main sequence (ZAMS) mass star (and perhaps a given metallicity) simply produces either an NS or a BH, but this fails to account for a myriad of other variables that may effect this outcome, such as spin, binarity, or even stochastic differences in the stellar structure near core collapse. We argue that instead a probabilistic description of NS versus BH formation may be better suited to account for the current uncertainties in understanding how massive stars die. We present an initial exploration of the probability that a star will make a BH as a function of its ZAMS mass, P BH(M ZAMS). Although we find that it is difficult to derive a unique P BH(M ZAMS) using current measurements of both the BH mass distribution and the degree of chemical enrichment by massive stars, we demonstrate how P BH(M ZAMS) changes with these various observational and theoretical uncertainties. We anticipate that future studies of Galactic BHs and theoretical studies of core collapse will refine P BH(M ZAMS) and argue that this framework is an important new step toward better understanding BH formation. A probabilistic description of BH formation will be useful as input for future population synthesis studies that are interested in the formation of X-ray binaries, the nature and event rate of gravitational wave sources, and answering questions about chemical enrichment.

  15. Method for fracturing subterranean formations

    SciTech Connect

    Almond, S. W.; Conway, M. W.

    1985-11-19

    The present invention relates to a thermally stable crosslinked gel fracturing fluid for use in the treatment of subterranean formations penetrated by a well bore. The fracturing fluid comprises an aqueous liquid, a gelling agent comprising a selected modified cellulose ether, a crosslinking agent and any additional additives that may be present. The fracturing fluid is thermally stable under shear at temperatures in excess of about 200/sup 0/ F.

  16. Memory Formation Shaped by Astroglia

    PubMed Central

    Zorec, Robert; Horvat, Anemari; Vardjan, Nina; Verkhratsky, Alexei

    2015-01-01

    Astrocytes, the most heterogeneous glial cells in the central nervous system (CNS), execute a multitude of homeostatic functions and contribute to memory formation. Consolidation of synaptic and systemic memory is a prolonged process and hours are required to form long-term memory. In the past, neurons or their parts have been considered to be the exclusive cellular sites of these processes, however, it has now become evident that astrocytes provide an important and essential contribution to memory formation. Astrocytes participate in the morphological remodeling associated with synaptic plasticity, an energy-demanding process that requires mobilization of glycogen, which, in the CNS, is almost exclusively stored in astrocytes. Synaptic remodeling also involves bidirectional astroglial-neuronal communication supported by astroglial receptors and release of gliosignaling molecules. Astroglia exhibit cytoplasmic excitability that engages second messengers, such as Ca2+, for phasic, and cyclic adenosine monophosphate (cAMP), for tonic signal coordination with neuronal processes. The detection of signals by astrocytes and the release of gliosignaling molecules, in particular by vesicle-based mechanisms, occurs with a significant delay after stimulation, orders of magnitude longer than that present in stimulus–secretion coupling in neurons. These particular arrangements position astrocytes as integrators ideally tuned to support time-dependent memory formation. PMID:26635551

  17. NSDF: Neuroscience Simulation Data Format.

    PubMed

    Ray, Subhasis; Chintaluri, Chaitanya; Bhalla, Upinder S; Wójcik, Daniel K

    2016-04-01

    Data interchange is emerging as an essential aspect of modern neuroscience. In the areas of computational neuroscience and systems biology there are multiple model definition formats, which have contributed strongly to the development of an ecosystem of simulation and analysis tools. Here we report the development of the Neuroscience Simulation Data Format (NSDF) which extends this ecosystem to the data generated in simulations. NSDF is designed to store simulator output across scales: from multiscale chemical and electrical signaling models, to detailed single-neuron and network models, to abstract neural nets. It is self-documenting, efficient, modular, and scalable, both in terms of novel data types and in terms of data volume. NSDF is simulator-independent, and can be used by a range of standalone analysis and visualization tools. It may also be used to store variety of experimental data. NSDF is based on the widely used HDF5 (Hierarchical Data Format 5) specification and is open, platform-independent, and portable.

  18. Theory of Planetary System Formation

    NASA Technical Reports Server (NTRS)

    Cassen, Patrick

    1996-01-01

    Observations and theoretical considerations support the idea that the Solar System formed by the collapse of tenuous interstellar matter to a disk of gas and dust (the primitive solar nebula), from which the Sun and other components separated under the action of dissipative forces and by the coagulation of solid material. Thus, planets are understood to be contemporaneous byproducts of star formation. Because the circumstellar disks of new stars are easier to observe than mature planetary systems, the possibility arises that the nature and variety of planets might be studied from observations of the conditions of their birth. A useful theory of planetary system formation would therefore relate the properties of circumstellar disks both to the initial conditions of star formation and to the consequent properties of planets to those of the disk. Although the broad outlines of such a theory are in place, many aspects are either untested, controversial, or otherwise unresolved; even the degree to which such a comprehensive theory is possible remains unknown.

  19. The formation of star clusters

    NASA Astrophysics Data System (ADS)

    Whitmore, Bradley C.

    The ability of HST to resolve objects ten times smaller than possible from the ground has re-juvenated the study of young star clusters. A recurrent morphological theme found in nearby resolved systems is the observation of young (typically 1-10 Myr), massive (103 - 104 Msolar), compact (ρ≍105 Msolar pc-3) clusters which have evacuated the gas and dust from a spherical region around themselves. New stars are being triggered into formation along the edges of the envelopes, with pillars (similar to the Eagle Nebula) of molecular gas streaming away from the regions of star formation. The prototype for these objects is 30 Doradus. Another major theme has been the discovery of large numbers of young (typically 1-500 Myr), massive (103 - 108 Msolar), compact star clusters in merging, starbursting, and even some barred and spiral galaxies. The brightest of these clusters have all the attributes expected of protoglobular clusters, hence allowing us to study the formation of globular clusters in the local universe rather than trying to ascertain how they formed ≍14 Gyr ago. The prototype is the Antennae Galaxy.

  20. SCALE FORMATION IN CHRYSOPHYCEAN ALGAE

    PubMed Central

    Brown, R. Malcolm; Franke, Werner W.; Kleinig, Hans; Falk, Heinz; Sitte, Peter

    1970-01-01

    The cell wall of the marine chrysophycean alga Pleurochrysis scherfellii is composed of distinct wall fragments embedded in a gelatinous mass. The latter is a polysaccharide of pectic character which is rich in galactose and ribose. These wall fragments are identified as scales. They have been isolated and purified from the vegetative mother cell walls after zoospore formation. Their ultrastructure is described in an electron microscope study combining sectioning, freeze-etch, and negative staining techniques. The scales consist of a layer of concentrically arranged microfibrils (ribbons with cross-sections of 12 to 25 x 25 to 40 A) and underlying radial fibrils of similar dimensions. Such a network-plate is densely coated with particles which are assumed to be identical to the pectic component. The microfibrils are resistant to strong alkaline treatment and have been identified as cellulose by different methods, including sugar analysis after total hydrolysis, proton resonance spectroscopical examination (NMR spectroscopy) of the benzoylated product, and diverse histochemical tests. The formation and secretion of the scales can be followed along the maturing Golgi cisternae starting from a pronounced dilated "polymerization center" as a completely intracisternal process which ends in the exocytotic extrusion of the scales. The scales reveal the very same ultrastructure within the Golgi cisternae as they do in the cell wall. The present finding represents the first evidence on cellulose formation by the Golgi apparatus and is discussed in relation to a basic scheme for cellulose synthesis in plant cells in general. PMID:5513606

  1. Modeling of Dynamic FRC Formation

    NASA Astrophysics Data System (ADS)

    Mok, Yung; Barnes, Dan; Dettrick, Sean

    2010-11-01

    We have developed a 2-D resistive MHD code, Lamy Ridge, to simulate the entire FRC formation process in Tri Alpha's C2 device, including initial formation, translation, merging and settling into equilibrium. Two FRC's can be created simultaneously, and then translated toward each other so that they merge into a single FRC. The code couples the external circuits around the formation tubes to the partially ionized plasma inside. Plasma and neutral gas are treated as two fluids. Dynamic and energetic equations, which take into account ionization and charge exchange, are solved in a time advance manner. The geometric shape of the vessel is specified by a set of inputs that defines the boundaries, which are handled by a cut-cell algorithm in the code. Multiple external circuits and field coils can be easily added, removed or relocated through individual inputs. The design of the code is modular and flexible so that it can be applied to future devices. The results of the code are in reasonable agreement with experimental measurements on the C2 device.

  2. Supernova Feedback in Galaxy Formation

    NASA Astrophysics Data System (ADS)

    Dubois, Y.; Teyssier, R.

    2008-06-01

    The hierarchical model of galaxy formation is known to suffer from the ``over-cooling'' problem: the high efficiency of radiative cooling results in too much baryonic matter in a condensed phase (namely, cold gas or stars) when compared to observations. A solution proposed by many authors (see Springel & Hernquist 2003; Fujita et al. 2004; Rasera & Teyssier 2005) is feedback due to supernova (SN) driven winds or active galactic nuclei. Modeling SN feedback by direct injection of thermal energy usually turns out to be inefficient in galaxy-scale simulations, due to the quasi-instantaneous radiation of the SN energy. To avoid this effect, we have developed a new method to incorporate SN feedback in cosmological simulations: using temporary test particles, we reproduce explicitly a local Sedov blast wave solution in the gas distribution. We have performed several self-consistent runs of isolated Navarro, Frenk, & White (1996, hereafter NFW) halos with radiative cooling, star formation, SN feedback and metal enrichment using the adaptive mesh refinement code RAMSES (Teyssier 2002). We have explored the influence of SN feedback on the formation and the evolution of galaxies with different masses. We have studied the efficiency of the resulting galactic winds, as a function of the mass of the parent halo.

  3. Illusory contour formation survives crowding.

    PubMed

    Lau, Jonathan Siu Fung; Cheung, Sing-Hang

    2012-06-12

    Flanked objects are difficult to identify using peripheral vision due to visual crowding, which limits conscious access to target identity. Nonetheless, certain types of visual information have been shown to survive crowding. Such resilience to crowding provides valuable information about the underlying neural mechanism of crowding. Here we ask whether illusory contour formation survives crowding of the inducers. We manipulated the presence of illusory contours through the (mis)alignment of the four inducers of a Kanizsa square. In the inducer-aligned condition, the observers judged the perceived shape (thin vs. fat) of the illusory Kanizsa square, manipulated by small rotations of the inducers. In the inducer-misaligned condition, three of the four inducers (all except the upper-left) were rotated 90°. The observers judged the orientation of the upper-left inducer. Crowding of the inducers worsened observers' performance significantly only in the inducer-misaligned condition. Our findings suggest that information for illusory contour formation survives crowding of the inducers. Crowding happens at a stage where the low-level featural information is integrated for inducer orientation discrimination, but not at a stage where the same information is used for illusory contour formation.

  4. NSDF: Neuroscience Simulation Data Format.

    PubMed

    Ray, Subhasis; Chintaluri, Chaitanya; Bhalla, Upinder S; Wójcik, Daniel K

    2016-04-01

    Data interchange is emerging as an essential aspect of modern neuroscience. In the areas of computational neuroscience and systems biology there are multiple model definition formats, which have contributed strongly to the development of an ecosystem of simulation and analysis tools. Here we report the development of the Neuroscience Simulation Data Format (NSDF) which extends this ecosystem to the data generated in simulations. NSDF is designed to store simulator output across scales: from multiscale chemical and electrical signaling models, to detailed single-neuron and network models, to abstract neural nets. It is self-documenting, efficient, modular, and scalable, both in terms of novel data types and in terms of data volume. NSDF is simulator-independent, and can be used by a range of standalone analysis and visualization tools. It may also be used to store variety of experimental data. NSDF is based on the widely used HDF5 (Hierarchical Data Format 5) specification and is open, platform-independent, and portable. PMID:26585711

  5. Theory of Remote Image Formation

    NASA Astrophysics Data System (ADS)

    Blahut, Richard E.

    2004-11-01

    In many applications, images, such as ultrasonic or X-ray signals, are recorded and then analyzed with digital or optical processors in order to extract information. Such processing requires the development of algorithms of great precision and sophistication. This book presents a unified treatment of the mathematical methods that underpin the various algorithms used in remote image formation. The author begins with a review of transform and filter theory. He then discusses two- and three-dimensional Fourier transform theory, the ambiguity function, image construction and reconstruction, tomography, baseband surveillance systems, and passive systems (where the signal source might be an earthquake or a galaxy). Information-theoretic methods in image formation are also covered, as are phase errors and phase noise. Throughout the book, practical applications illustrate theoretical concepts, and there are many homework problems. The book is aimed at graduate students of electrical engineering and computer science, and practitioners in industry. Presents a unified treatment of the mathematical methods that underpin the algorithms used in remote image formation Illustrates theoretical concepts with reference to practical applications Provides insights into the design parameters of real systems

  6. Vortex Formation in Shallow Flows

    NASA Astrophysics Data System (ADS)

    Rockwell, Donald

    2006-11-01

    Vortical structures having a scale much larger than the depth of the flow, which arise in bluff body wakes, jets, and mixing layers generated in shallow layers, show distinctive features due to the influence of bed friction. Cinema techniques of high-image-density particle image velocimetry are employed to characterize quasi-two-dimensional and three-dimensional aspects of the vortex development in terms of: patterns of vorticity; flow topology involving definition of critical points; and global spectral and cross-spectral analyses, based on simultaneous time records at thousands of grid points of the cinema imaging. Taken together, these representations lead to an understanding of the relationship between coherent vortex development and unsteadiness along the bed and, furthermore, provide a basis for exploration of concepts generic to separated shear layers in shallow flows. These concepts include: suppression of a primary mode of vortex formation due to bed friction and emergence of another mode; resonant coupling between a gravity wave of the shallow layer and vortex formation, leading to large-scale vortices; and passive and active (open loop) control, which can either retard or enhance the onset of vortex formation. These studies suggest opportunities for further investigation on both experimental and numerical fronts. Collaboration with Haojun Fu, Alis Ekmekci, Jung-Chang Lin, and Muammer Ozgoren is gratefully acknowledged.

  7. Sedimentology and paleoenvironments of the Las Chacritas carbonate paleolake, Cañadón Asfalto Formation (Jurassic), Patagonia, Argentina

    NASA Astrophysics Data System (ADS)

    Cabaleri, Nora G.; Benavente, Cecilia A.

    2013-02-01

    The Las Chacritas Member is the lower part of the Cañadón Asfalto Formation (Jurassic). The unit is a completely continental limestone succession with volcanic contributions that were deposited during the development of the Cañadón Asfalto Rift Basin (Chubut province, Patagonia, Argentina). A detailed sedimentological analysis was performed in the Fossati depocenter to determine the paleoenvironments that developed in the context of this rift. The Las Chacritas Member represents a carbonate paleolake system with ramp-shaped margins associated with wetlands that were eventually affected by subaerial exposure and pedogenesis. This process is represented by three main subenvironments: a) a lacustrine setting sensu stricto (lacustrine limestone facies association), represented by Mudstones/Wackestones containing porifera spicules (F1), Intraclastic packstones (F6) and Tabular stromatolites (F10) in which deposition and diagenesis were entirely subaqueous; b) a palustrine setting (palustrine limestone facies association) containing Microbial Mudstones (F2), Intraclastic sandy packstone with ostracode remains (F3), Oncolitic packstone (F5), Brecciated limestone (F7) and Nodular-Mottled limestone (F8) representing shallow marginal areas affected by groundwater fluctuations and minor subaerial exposure; and c) a pedogenic paleoenvironment (pedogenic limestone facies association) including Intraclastic limestone (F4) and Packstones containing Microcodium (F9) facies displaying the major features of subaerial exposure, pedogenic diagenesis and the development of paleosols. The fluvial-palustrine-lacustrine succession shows a general shallow upward trend in which contraction-expansion cycles are represented (delimited by exposure and surface erosion). The variations in the successive formations reflect the responses to fluctuations in a combination of two major controls, the tectonic and local climatic variables. The predominance of the palustrine facies associations was

  8. Formation mechanisms of metal colloids

    NASA Astrophysics Data System (ADS)

    Halaciuga, Ionel

    Highly dispersed uniform metallic particles are widely used in various areas of technology and medicine and are likely to be incorporated into many other applications in the future. It is commonly accepted that size, shape and composition of the particles represent critical factors in most applications. Thus, understanding the mechanisms of formation of metal particles and the ways to control the physical (e.g. shape, size) and chemical (e.g. composition) properties is of great importance. In the current research, the formation of uniform silver spheres is investigated experimentally. The parameters that influence the formation of silver particles when concentrated iso-ascorbic acid and silver-polyamine complex solutions are rapidly mixed were studied in the absence of dispersants. We found that by varying the nature of the amine, temperature, concentration of reactants, silver/amine molar ratio, and the nature of the silver salt, the size of the resulting silver particles can be varied in a wide range (0.08--1.5 microm). The silver particles were formed by aggregation of nanosize subunits as substantiated by both electron microscopy and X-ray diffraction techniques and by the vivid rapid color changes during the chemical precipitation process. From the practical standpoint, the goal of this research was to prepare well dispersed spherical silver particles having a relatively smooth surface and a diameter of about 1 microm to satisfy the demands of the current electronic materials market. A two stage particle growth model previously developed to explain the narrow size distribution occurring in synthesis of gold spheres was applied to the present experimental system, and the parameters that control the size distribution characteristics were identified. The kinetic parameter required to match the final particle size was found to be in agreement with the one used previously in modeling formation of gold spheres, suggesting that similar kinetics governs the

  9. Dioxin formation from waste incineration.

    PubMed

    Shibamoto, Takayuki; Yasuhara, Akio; Katami, Takeo

    2007-01-01

    There has been great concern about dioxins-polychlorinated dibenzo dioxins (PCDDs), polychlorinated dibenzo furans (PCDFs), and polychlorinated biphenyls (PCBs)-causing contamination in the environment because the adverse effects of these chemicals on human health have been known for many years. Possible dioxin-contamination has received much attention recently not only by environmental scientists but also by the public, because dioxins are known to be formed during the combustion of industrial and domestic wastes and to escape into the environment via exhaust gases from incinerators. Consequently, there is a pressing need to investigate the formation mechanisms or reaction pathways of these chlorinated chemicals to be able to devise ways to reduce their environmental contamination. A well-controlled small-scale incinerator was used for the experiments in the core references of this review. These articles report the investigation of dioxin formation from the combustion of various waste-simulated samples, including different kinds of paper, various kinds of wood, fallen leaves, food samples, polyethylene (PE), polystyrene (PS), polyvinyl chloride (PVC), polyvinylidene chloride, polyethylene tetraphthalate (PET), and various kinds of plastic products. These samples were also incinerated with inorganic chlorides (NaCl, KCl, CuCI2, MgCl2, MnCl2, FeCl2, CoCl2, fly ash, and seawater) or organic chlorides (PVC, chlordane, and pentachlorophenol) to investigate the role of chlorine content and/or the presence of different metals in dioxin formation. Some samples, such as newspapers, were burned after they were impregnated with NaCl or PVC, as well as being cocombusted with chlorides. The roles of incineration conditions, including chamber temperatures, O2 concentrations, and CO concentrations, in dioxin formation were also investigated. Dioxins (PCDDs, PCDFs, and coplanar-PCBs) formed in the exhaust gases from a controlled small-scale incinerator, where experimental waste

  10. Core formation in silicate bodies

    NASA Astrophysics Data System (ADS)

    Nimmo, F.; O'Brien, D. P.; Kleine, T.

    2008-12-01

    Differentiation of a body into a metallic core and silicate mantle occurs most efficiently if temperatures are high enough to allow at least the metal to melt [1], and is enhanced if matrix deformation occurs [2]. Elevated temperatures may occur due to either decay of short-lived radio-isotopes, or gravitational energy release during accretion [3]. For bodies smaller than the Moon, core formation happens primarily due to radioactive decay. The Hf-W isotopic system may be used to date core formation; cores in some iron meteorites and the eucrite parent body (probably Vesta) formed within 1 My and 1-4~My of solar system formation, respectively [4]. These formation times are early enough to ensure widespread melting and differentiation by 26Al decay. Incorporation of Fe60 into the core, together with rapid early mantle solidification and cooling, may have driven early dynamo activity on some bodies [5]. Iron meteorites are typically depleted in sulphur relative to chondrites, for unknown reasons [6]. This depletion contrasts with the apparently higher sulphur contents of cores in larger planetary bodies, such as Mars [7], and also has a significant effect on the timing of core solidification. For bodies of Moon-size and larger, gravitational energy released during accretion is probably the primary cause of core formation [3]. The final stages of accretion involve large, stochastic collisions [8] between objects which are already differentiated. During each collision, the metallic cores of the colliding objects merge on timescales of a few hours [9]. Each collision will reset the Hf-W isotopic signature of both mantle and core, depending on the degree to which the impactor core re-equilibrates with the mantle of the target [10]. The re-equilibration efficiency depends mainly on the degree to which the impactor emulsifies [11], which is very uncertain. Results from N-body simulations [8,12] suggest that significant degrees of re- equilibration are required [4,10]. Re

  11. Biofilm formation by Staphylococcus haemolyticus.

    PubMed

    Fredheim, Elizabeth Gladys Aarag; Klingenberg, Claus; Rohde, Holger; Frankenberger, Stephanie; Gaustad, Peter; Flaegstad, Trond; Sollid, Johanna Ericson

    2009-04-01

    Infections due to coagulase-negative staphylococci (CoNS) most frequently occur after the implantation of medical devices and are attributed to the biofilm-forming potential of CoNS. Staphylococcus haemolyticus is the second most frequently isolated CoNS from patients with hospital-acquired infections. There is only limited knowledge of the nature of S. haemolyticus biofilms. The aim of this study was to characterize S. haemolyticus biofilm formation. We analyzed the biofilm-forming capacities of 72 clinical S. haemolyticus isolates. A detachment assay with NaIO(4), proteinase K, or DNase was used to determine the main biofilm components. Biofilm-associated genes, including the ica operon, were analyzed by PCR, and the gene products were sequenced. Confocal laser scanning microscopy (CLSM) was used to elucidate the biofilm structure. Fifty-three isolates (74%) produced biofilms after growth in Trypticase soy broth (TSB) with glucose, but only 22 (31%) produced biofilms after growth in TSB with NaCl. It was necessary to dissolve the biofilm in ethanol-acetone to measure the optical density of the full biofilm mass. DNase, proteinase K, and NaIO(4) caused biofilm detachment for 100%, 98%, and 38% of the isolates, respectively. icaRADBC and polysaccharide intercellular adhesin (PIA) production were found in only two isolates. CLSM indicated that the biofilm structure of S. haemolyticus clearly differs from that of S. epidermidis. We conclude that biofilm formation is a common phenotype in clinical S. haemolyticus isolates. In contrast to S. epidermidis, proteins and extracellular DNA are of functional relevance for biofilm accumulation, whereas PIA plays only a minor role. The induction of biofilm formation and determination of the biofilm mass also needed to be optimized for S. haemolyticus.

  12. A Fossil Group in Formation

    NASA Astrophysics Data System (ADS)

    Miller, Eric D.; Rappaport, Saul A.; McDonald, Michael; Bautz, Mark W.; Grant, Catherine E.; Veilleux, Sylvain

    2016-04-01

    In the current picture of hierarchical structure formation, galaxy groups play a vital role as the seeds from which large assemblies of matter form. Compact groups are also important environments in which to watch the fueling of star formation and AGN activity, as the conditions are ideal for galaxy-galaxy interactions. We have identified a galaxy system that may represent an intermediate or transition stage in group evolution. Shakhbazyan 1 (or SHK 1) is a remarkably compact collection of about ten massive, red-sequence galaxies within a region 100 kpc across. Several of these galaxies show signs of AGN activity, and new, deep optical observations with the Discovery Channel Telescope reveal an extended stellar envelope surrounding the galaxies. This envelope is much more extended than what would be expected from a superposition of normal galaxy envelopes, and it indicates a large amount of intra-group starlight, evidence that the galaxies in SHK 1 are dynamically interacting.We here present new Chandra spectral imaging observations of this unusual system that confirm the presence of an X-ray-emitting diffuse intra-group medium (IGM), with a temperature of 1.5 keV and X-ray luminosity of 1043 erg/s. Assuming hydrostatic equilibrium, the system is about 1/3 as massive as expected from the optical richness. In addition, three of the ten central galaxies exhibit signatures of X-ray AGN. The under-luminous IGM, high density of bright galaxies, and evidence for galaxy-galaxy interaction indicate that this system may be in a transition stage of galaxy merging, similar to that expected in the formation of a fossil group. Alternatively, SHK 1 may consist of multiple poor groups in the final stages of merging along our line of sight. We explore these scenarios and outline paths of future study for this enigmatic system.

  13. WOUND HEALING AND COLLAGEN FORMATION

    PubMed Central

    Ross, Russell; Benditt, Earl P.

    1961-01-01

    The regular sequence encountered in healing guinea pig skin wounds has been examined by methods of light and electron microscopy. Observations on cell populations, their fine structure, and fibril formation in the connective tissue have been made. Linear incisions in the skin of normal female guinea pigs weighing 300 to 350 grams were allowed to heal. The wounds were then excised, fixed with buffered 2 per cent osmium tetroxide, and postfixed in neutral buffered formalin, at 16 and 24 hours and at 3, 5, 9, and 14 days after wounding. They were then embedded in epoxy resin. In the inflammatory phase the exudate observed in the early wounds consists largely of polymorphonuclear neutrophilic leukocytes, macrophages, fibrin, and free extracellular organelles from the disrupted inflammatory cells. These organelles later appear in vacuoles in the cytoplasm of the macrophages. Fibroblasts first appear at 24 hours, and show extensive development and dilatation of the endoplasmic reticulum, which sometimes contains moderately dense flocculent material. In addition, these fibroblasts have enlarged mitochondria and condensations of filamentous material within the cytoplasm near the cell surface. Occasional myelin figures and moderately dense, 0.5 to 1.0 micron bodies are found within the cytoplasm of the early fibroblasts. Collagen fibrils are first seen at 3 days extracellularly near the cell surfaces. They appear at the later times in two populations of sizes. With increasing wound age the fibroblasts retain their morphology and the wounds decrease in cellularity concomitantly with the formation of increasing amounts of collagen. Several proposed mechanisms of collagen fibril formation are discussed in relation to the observed phenomena. The problem of correlating fibril diameter with the appearance of the periodic structure of collagen in relation to the minimal size fibril which would be anticipated to display this appearance is discussed. PMID:14494202

  14. Pattern formation in geochemical systems

    NASA Astrophysics Data System (ADS)

    Katsev, Sergei

    2002-08-01

    Compositional patterns are extremely common in natural minerals. While, in many cases, variations in the solid mineral composition reflect the external changes in the environment at the time of the mineral formation, the role of self-organization is increasingly acknowledged. For example, in reaction-transport systems, the patterns may form spontaneously from an unpatterned state at the time of crystal growth and then become preserved by being "frozen" in the solid mineral. In this work, the pattern formation by self-organization is investigated by means of model construction and computer simulations in several minerals from different geologic environments. The impact of environmental noise is investigated on a model of oscillatory zoning in plagioclase feldspar. It is shown that environmental noise can lead to pattern formation such as oscillatory zoning, even when no deterministic periodic solutions exist. Coherence resonance close to the Hopf bifurcation is observed. Oscillatory zoning in barite-celestite system is simulated to quantitatively describe the results of the previously reported nucleation and growth experiments. The zoning is thought to be formed by autocatalytic growth from an aqueous solution. In addition to the description of the reaction-diffusion system in terns of partial and ordinary differential equations, a cellular automata model is proposed for the first time for this oscillatory crystallization type of problems. A quantitative model of banding in Mississippi Valley-type sphalerite is presented. Banded ring-like patterns are shown to arise due to a self-propagating sequence of growth and dissolution (coarsening wave). A two-dimensional model is presented for the first time and the conditions for the pattern generation and preservation are discussed. A number of time series analysis techniques are applied to characterize the compositional patterns observed in natural minerals as well as in the colored rythmites found in the marine clay

  15. Mechanism of formation of hydantoins

    SciTech Connect

    Worman, J.J.; Uhrich, K.; Olson, E.; Diehl, J.; Farnum, S.; Hawthorne, S.

    1985-10-01

    Hydantoins, (I), are biologically active compounds which occur in nature and have been isolated from such sources as sugar beets and butterfly wings. Synthetic analogs have found widespread use as anticonvulsant drugs, bacteriocides, stabilizers in photographic film, and in the preparation of high temperature epoxy resins. Uses, preparation, and reactions of hydantoins have been extensively studied and are reported elsewhere. Recently a number of hydantoin isomers have been detected and identified in coal gasification condensate water from the gasification of Indian Head (ND) lignite in a slagging fixed bed gasifier. The hydantoins constitute a major portion of the organics in the condensate water. In generation the concentrations of hydantoins found in the condensate water from an ash gasifier are smaller than those found from the slagging process. Lignite coal reacting in a slagging gasifier gives the largest concentration of hydantoins in the condensate water. The major isomer in the coal gasification condensate water is 5,5-dimethylhydantoin (DMH). DMH is formed from individual species (acetone, cyanide, ammonia, and carbonate) in the condensate water and does not form directly in the gasifier. The rate of formation of DMH was first order in all of the reactants as expressed by the equation: Rate of formation of DMH = (Acetone) (HCN) (NH/sub 3/) (CO/sub 2/). This kinetic data is valuable in predicting the rate of formation of DMH in coal gasification condensate water, provided the model is applicable. A mechanism consistent with the kinetic data and partially verified by others is shown in Scheme 1. 13 refs.

  16. Biofilm formation by Staphylococcus haemolyticus.

    PubMed

    Fredheim, Elizabeth Gladys Aarag; Klingenberg, Claus; Rohde, Holger; Frankenberger, Stephanie; Gaustad, Peter; Flaegstad, Trond; Sollid, Johanna Ericson

    2009-04-01

    Infections due to coagulase-negative staphylococci (CoNS) most frequently occur after the implantation of medical devices and are attributed to the biofilm-forming potential of CoNS. Staphylococcus haemolyticus is the second most frequently isolated CoNS from patients with hospital-acquired infections. There is only limited knowledge of the nature of S. haemolyticus biofilms. The aim of this study was to characterize S. haemolyticus biofilm formation. We analyzed the biofilm-forming capacities of 72 clinical S. haemolyticus isolates. A detachment assay with NaIO(4), proteinase K, or DNase was used to determine the main biofilm components. Biofilm-associated genes, including the ica operon, were analyzed by PCR, and the gene products were sequenced. Confocal laser scanning microscopy (CLSM) was used to elucidate the biofilm structure. Fifty-three isolates (74%) produced biofilms after growth in Trypticase soy broth (TSB) with glucose, but only 22 (31%) produced biofilms after growth in TSB with NaCl. It was necessary to dissolve the biofilm in ethanol-acetone to measure the optical density of the full biofilm mass. DNase, proteinase K, and NaIO(4) caused biofilm detachment for 100%, 98%, and 38% of the isolates, respectively. icaRADBC and polysaccharide intercellular adhesin (PIA) production were found in only two isolates. CLSM indicated that the biofilm structure of S. haemolyticus clearly differs from that of S. epidermidis. We conclude that biofilm formation is a common phenotype in clinical S. haemolyticus isolates. In contrast to S. epidermidis, proteins and extracellular DNA are of functional relevance for biofilm accumulation, whereas PIA plays only a minor role. The induction of biofilm formation and determination of the biofilm mass also needed to be optimized for S. haemolyticus. PMID:19144798

  17. New Paradigms for Asteroid Formation

    NASA Astrophysics Data System (ADS)

    Johansen, A.; Jacquet, E.; Cuzzi, J. N.; Morbidelli, A.; Gounelle, M.

    Asteroids and meteorites provide key evidence on the formation of planetesimals in the solar system. Asteroids are traditionally thought to form in a bottom-up process by coagulation within a population of initially kilometer-scale planetesimals. However, new models challenge this idea by demonstrating that asteroids of sizes from 100 to 1000 km can form directly from the gravitational collapse of small particles that have organized themselves in dense filaments and clusters in the turbulent gas. Particles concentrate passively between eddies down to the smallest scales of the turbulent gas flow and inside large-scale pressure bumps and vortices. The streaming instability causes particles to take an active role in the concentration, by piling up in dense filaments whose friction on the gas reduces the radial drift compared to that of isolated particles. In this chapter we review new paradigms for asteroid formation and critically compare them against the observed properties of asteroids as well as constraints from meteorites. Chondrules of typical sizes from 0.1 to 1 mm are ubiquitous in primitive meteorites and likely represent the primary building blocks of asteroids. Chondrule-sized particles are nevertheless tightly coupled to the gas via friction and are therefore hard to concentrate in large amounts in the turbulent gas. We review recent progress on understanding the incorporation of chondrules into the asteroids, including layered accretion models where chondrules are accreted onto asteroids over millions of years. We highlight in the end 10 unsolved questions in asteroid formation where we expect that progress will be made over the next decade.

  18. Petrophysical evaluation of subterranean formations

    DOEpatents

    Klein, James D; Schoderbek, David A; Mailloux, Jason M

    2013-05-28

    Methods and systems are provided for evaluating petrophysical properties of subterranean formations and comprehensively evaluating hydrate presence through a combination of computer-implemented log modeling and analysis. Certain embodiments include the steps of running a number of logging tools in a wellbore to obtain a variety of wellbore data and logs, and evaluating and modeling the log data to ascertain various petrophysical properties. Examples of suitable logging techniques that may be used in combination with the present invention include, but are not limited to, sonic logs, electrical resistivity logs, gamma ray logs, neutron porosity logs, density logs, NRM logs, or any combination or subset thereof.

  19. Testing Magnetic Star Formation Theory

    NASA Astrophysics Data System (ADS)

    Crutcher, Richard M.; Hakobian, Nicholas; Troland, Thomas H.

    2009-02-01

    Zeeman observations of molecular clouds yield the line-of-sight component B LOS of the magnetic vector B, which makes it possible to test the two major extreme-case theories of what drives star formation—ambipolar diffusion or turbulence. However, only one of the three components of B is measurable, so tests have been statistical rather than direct, and they have not been definitive. We report here observations of the Zeeman effect in the 18 cm lines of OH in the envelope regions surrounding four molecular cloud cores toward which detections of B LOS have been achieved in the same lines, and evaluate the ratio of mass-to-magnetic flux, M/Φ, between the cloud core and envelope. This relative M/Φ measurement reduces uncertainties in previous studies, such as the angle between B and the line of sight and the value of [OH/H]. Our result is that for all four clouds, the ratios R of the core to the envelope values of M/Φ are less than 1. Stated another way, the ratios R' of the core to the total cloud M/Φ are less than 1. The extreme case or idealized (no turbulence) ambipolar diffusion theory of core formation requires the ratio of the central to total M/Φ to be approximately equal to the inverse of the original subcritical M/Φ, or R' > 1. The probability that all four of our clouds have R' > 1 is 3 × 10-7 our results are therefore significantly in contradiction with the hypothesis that these four cores were formed by ambipolar diffusion. Highly super-Alfvénic turbulent simulations yield a wide range of relative M/Φ, but favor a ratio R < 1, as we observe. Our experiment is limited to four clouds, and we can only directly test the predictions of the extreme-case "idealized" models of ambipolar-diffusion driven star formation, which have a regular magnetic field morphology. Nonetheless, our experimental results are not consistent with the "idealized" strong field, ambipolar diffusion theory of star formation. Comparisons of our results with more realistic

  20. Formation Flying and Deformable Instruments

    SciTech Connect

    Rio, Yvon

    2009-05-11

    Astronomers have always attempted to build very stable instruments. They fight all that can cause mechanical deformation or image motion. This has led to well established technologies (autoguide, active optics, thermal control, tip/tilt correction), as well as observing methods based on the use of controlled motion (scanning, micro scanning, shift and add, chopping and nodding). Formation flying disturbs this practice. It is neither possible to reduce the relative motion to very small amplitudes, nor to control it at will. Some impacts on Simbol-X instrument design, and operation are presented.

  1. Formation Flying and Deformable Instruments

    NASA Astrophysics Data System (ADS)

    Rio, Yvon

    2009-05-01

    Astronomers have always attempted to build very stable instruments. They fight all that can cause mechanical deformation or image motion. This has led to well established technologies (autoguide, active optics, thermal control, tip/tilt correction), as well as observing methods based on the use of controlled motion (scanning, micro scanning, shift and add, chopping and nodding). Formation flying disturbs this practice. It is neither possible to reduce the relative motion to very small amplitudes, nor to control it at will. Some impacts on Simbol-X instrument design, and operation are presented.

  2. Formation flight astronomical survey telescope

    NASA Astrophysics Data System (ADS)

    Tsunemi, Hiroshi

    2012-03-01

    Formation Flight Astronomical Survey Telescope (FFAST) is a project for hard X-ray observation. It consists of two small satellites; one (telescope satellite) has a super mirror covering the energy range up to 80 keV while the other (detector satellite) has an scintillator deposited CCD (SDCCD) having good spatial resolution and high efficiency up to 100 keV. Two satellites will be put into individual Kepler orbits forming an X-ray telescope with a focal length of 20 m. They will be not in pointing mode but in survey mode to cover a large sky region.

  3. Zonal flow as pattern formation

    NASA Astrophysics Data System (ADS)

    Parker, Jeffrey B.; Krommes, John A.

    2013-10-01

    Zonal flows are well known to arise spontaneously out of turbulence. We show that for statistically averaged equations of the stochastically forced generalized Hasegawa-Mima model, steady-state zonal flows, and inhomogeneous turbulence fit into the framework of pattern formation. There are many implications. First, the wavelength of the zonal flows is not unique. Indeed, in an idealized, infinite system, any wavelength within a certain continuous band corresponds to a solution. Second, of these wavelengths, only those within a smaller subband are linearly stable. Unstable wavelengths must evolve to reach a stable wavelength; this process manifests as merging jets.

  4. Electrochemical formation of field emitters

    DOEpatents

    Bernhardt, Anthony F.

    1999-01-01

    Electrochemical formation of field emitters, particularly useful in the fabrication of flat panel displays. The fabrication involves field emitting points in a gated field emitter structure. Metal field emitters are formed by electroplating and the shape of the formed emitter is controlled by the potential imposed on the gate as well as on a separate counter electrode. This allows sharp emitters to be formed in a more inexpensive and manufacturable process than vacuum deposition processes used at present. The fabrication process involves etching of the gate metal and the dielectric layer down to the resistor layer, and then electroplating the etched area and forming an electroplated emitter point in the etched area.

  5. Branch formation during organ development

    PubMed Central

    Gjorevski, Nikolce; Nelson, Celeste M.

    2010-01-01

    Invertebrates and vertebrates use branching morphogenesis to build epithelial trees to maximize the surface area of organs within a given volume. Several molecular regulators of branching have recently been discovered, a number of which are conserved across different organs and species. Signals that control branching at the cellular and tissue levels are also starting to emerge, and are rapidly unveiling the physical nature of branch development. Here we discuss the molecular, cellular and physical processes that govern branch formation and highlight the major outstanding questions in the field. PMID:20890968

  6. Zonal flow as pattern formation

    SciTech Connect

    Parker, Jeffrey B.; Krommes, John A.

    2013-10-15

    Zonal flows are well known to arise spontaneously out of turbulence. We show that for statistically averaged equations of the stochastically forced generalized Hasegawa-Mima model, steady-state zonal flows, and inhomogeneous turbulence fit into the framework of pattern formation. There are many implications. First, the wavelength of the zonal flows is not unique. Indeed, in an idealized, infinite system, any wavelength within a certain continuous band corresponds to a solution. Second, of these wavelengths, only those within a smaller subband are linearly stable. Unstable wavelengths must evolve to reach a stable wavelength; this process manifests as merging jets.

  7. The formation of interstellar jets

    NASA Technical Reports Server (NTRS)

    Tenorio-Tagle, G.; Canto, J.; Rozyczka, M.

    1988-01-01

    The formation of interstellar jets by convergence of supersonic conical flows and the further dynamical evolution of these jets are investigated theoretically by means of numerical simulations. The results are presented in extensive graphs and characterized in detail. Strong radiative cooling is shown to result in jets with Mach numbers 2.5-29 propagating to lengths 50-100 times their original widths, with condensation of swept-up interstellar matter at Mach 5 or greater. The characteristics of so-called molecular outflows are well reproduced by the simulations of low-Mach-number and quasi-adiabatic jets.

  8. Comet Formation in Collapsing Pebble Clouds: Pebble Formation

    NASA Astrophysics Data System (ADS)

    Lorek, Sebastian; Lacerda, Pedro; Blum, Jürgen

    2016-10-01

    The formation of comets by gradual growth from (sub-)micron sized ice and dust monomers to km-sized bodies suffers from growth barriers (bouncing, fragmentation, drift). Growth stalls at sizes between mm and m, rendering it considerably difficult to form km-sized objects. However, the streaming instability and subsequent gravitational collapse of clouds of pebbles (particle agglomerates) provide an alternative. The pebbles require Stokes numbers between 0.01 and 3, which corresponds to sizes between mm and dm, unless the pebbles are very porous. Furthermore, the local solid/gas density ratio must be near unity and the local total mass in solids must be >2-3x higher than the minimum mass solar nebula value (1% of gas mass). The gravitational collapse of the pebble clouds then bypasses the growth barriers, forming km-sized bodies directly. The observed bulk properties of comets, e.g. porosity near 80%, are consistent with this scenario. Okuzumi et al. (2012) showed that including porosity comets can form directly via coagulation from sub-micron monomers. However, this relies on using 0.1 micron monomers and pure sticking collisions. Krijt et al. (2015) included erosion and found that highly porous pebbles around 109 g in mass can form and might trigger the streaming instability. Drazkowska & Dullemond (2014) showed that compact coagulation can lead to triggering the streaming instability. All those studies include only ice and a simplified collision model. However, a large fraction of a comet's mass is dust. Here, we develop a pebble formation model that includes sticking, bouncing, mass transfer/erosion, and fragmentation, as well as porosity. To take dust and ice into account, we extended the collision model for the treatment of mixed pebbles by linearly interpolating the threshold velocities and compression curves between the cases of pure dust and pure ice based on the fractional abundance of dust monomers. Our simulations show that pebble formation with the full

  9. Choosing to write the paper format thesis.

    PubMed

    Morris, H M; Tipples, G

    1998-04-01

    Graduate students today may be faced with the option of writing either a traditional format thesis or a paper format thesis. In contrast to the traditional format in which the text body consists of four or five chapters, the body of the paper format thesis can be comprised of an introductory chapter, two or more papers written as publishable manuscripts, and a conclusion. In this article, an overview of the paper format thesis is presented and contrasted with the traditional format thesis. The description of the paper format thesis is followed by its advantages and disadvantages for writers and readers. It is by weighing all possible pros and cons, as well as considering one's individual situation, that the graduate student will be able to decide which format of thesis to write.

  10. SAR polar format implementation with MATLAB.

    SciTech Connect

    Martin, Grant D.; Doerry, Armin Walter

    2005-11-01

    Traditional polar format image formation for Synthetic Aperture Radar (SAR) requires a large amount of processing power and memory in order to accomplish in real-time. These requirements can thus eliminate the possible usage of interpreted language environments such as MATLAB. However, with trapezoidal aperture phase history collection and changes to the traditional polar format algorithm, certain optimizations make MATLAB a possible tool for image formation. Thus, this document's purpose is two-fold. The first outlines a change to the existing Polar Format MATLAB implementation utilizing the Chirp Z-Transform that improves performance and memory usage achieving near realtime results for smaller apertures. The second is the addition of two new possible image formation options that perform a more traditional interpolation style image formation. These options allow the continued exploration of possible interpolation methods for image formation and some preliminary results comparing image quality are given.

  11. XML Format for SESAME and LEOS

    SciTech Connect

    Durrenberger, J K; Neely, J R; Sterne, P A

    2009-04-29

    The objective of this document is to describe the XML format used by LLNL and LANL to represent the equation-of-state and related material information in the LEOS and SESAME data libraries. The primary purpose of this document is to describe a specific XML format for representing EOS data that is tailored to the nature of the underlying data and is amenable to conversion to both legacy SESAME and LEOS binary formats. The secondary purpose is to describe an XML format that lends itself to a 'natural' representation in a binary file format of the SESAME, pdb or hdf5 form so that this format and related tools can be used for the rapid and efficient development and implementation of prototype data structures. This document describes the XML format only. A working knowledge of LEOS and SESAME formats is assumed.

  12. Hydraulic fracturing in subterranean formations

    SciTech Connect

    Borchardt, J.K.

    1991-06-18

    This patent describes a process for the hydraulic fracturing of subterranean formations which comprises a step for the introduction into the formation at fracturing pressure of a fracturing fluid comprising solid particulate suspended in a fluid dispersion. It comprises water, a component selected from the group consisting of supercritical carbon dioxide and gaseous nitrogen, carbon dioxide and C{sub 1} to C{sub 3} hydrocarbons, and mixtures thereof, and one or more polysaccharide surfactants of the formula RO(R{sup 1}O){sub x}Sacc{sub z}, wherein R is a monovalent organic radical having a carbon number in the range from about 7 to 24. R{sup 1} represents a divalent hydrocarbon radical containing from about 2 to about 4 carbon atoms, x is a number having an average value in the range from 0 to about 12.0, and Saccz represents an average number z between about 0.7 and 10.0 of moieties derived from reducing saccharides containing 5 or 6 carbon atoms.

  13. Microbubble formation from plasma polymers.

    PubMed

    Shahravan, Anaram; Yelamarty, Srinath; Matsoukas, Themis

    2012-09-27

    We document the formation of liquid-like particles in a toluene glow discharge that subsequently solidify via a process that releases hydrogen to form a solid microbubble with micrometer-size diameter, nanometer-size shell thickness, and high volume fraction, in excess of 90%. Liquid-like particles are produced in a toluene plasma under conditions that promote low degree of cross-linking (low power, high pressure). When these are transferred for observation in TEM, they are seen to transform under irradiation by the electron beam into solid bubbles with diameter of about 3 μm. This transformation also takes place under laser irradiation of sufficient power and under heating. We present evidence that the formation of these microbubbles is due to solidification of the liquid-like precursor that is accompanied by release of hydrogen. This mechanism is supported by a geometric model that provides a quantitative description of the particle size before and after solidification. These unique stimuli-responsive particles exhibit the potential of using temperature, electron beam, or laser as a source to change their size and structure which may find application in thermal insulators, lightweight materials, and light scattering agents.

  14. Formation mechanism of calcium hexaluminate

    NASA Astrophysics Data System (ADS)

    Chen, Jun-hong; Chen, Hai-yang; Yan, Ming-wei; Cao, Zheng; Mi, Wen-jun

    2016-10-01

    To investigate the formation mechanism of calcium hexaluminate (CaAl12O19, CA6), the analytically pure alumina and calcia used as raw materials were mixed in CaO/Al2O3 ratio of 12.57:137.43 by mass. The raw materials were ball-milled and shaped into green specimens, and fired at 1300-1600°C. Then, the phase composition and microstructure evolution of the fired specimen were studied, and a first principle calculation was performed. The results show that in the reaction system of CaO and Al2O3, a small amount of CA6 forms at 1300°C, and greater amounts are formed at 1400°C and higher temperatures. The reaction is as follows: CaO·2Al2O3 (CA2) + 4Al2O3 → CA6. The diffusions of Ca2+ in CA2 towards Al2O3 and Al3+ in Al2O3 towards CA2 change the structures in different degrees of difficulty. Compared with the difficulty of structural change and the corresponding lattice energy change, it is deduced that the main formation mechanism is the diffusion of Ca2+ in CA2 towards Al2O3.

  15. Bar Formation from Galaxy Flybys

    NASA Astrophysics Data System (ADS)

    Holley-Bockelmann, Kelly; Lang, Meagan; Sinha, Manodeep

    2016-05-01

    Both simulations and observations reveal that flybys—fast, one-time interactions between two galaxy halos—are surprisingly common, comparable to galaxy mergers. Since these are rapid, transient events with the closest approach well outside the galaxy disk, it is unclear if flybys can transform the galaxy in a lasting way. We conduct collisionless N-body simulations of three coplanar flyby interactions between pure-disk galaxies to take a first look at the effects flybys have on disk structure, with particular focus on stellar bar formation. We find that some flybys are capable of inciting a bar; bars form in both galaxies during our 1:1 interaction and in the secondary during our 10:1 interaction. The bars formed have ellipticities >0.5, sizes on the order of the scale length of the disk, and persist to the end of our simulations, ~5 Gyr after pericenter. The ability of flybys to incite bar formation implies that many processes associated with secular bar evolution may be more closely tied with flyby interactions than previously thought.

  16. Protoporphyrin formation in Rhizobium japonicum.

    PubMed Central

    Keithly, J H; Nadler, K D

    1983-01-01

    The obligately aerobic soybean root nodule bacterium Rhizobium japonicum produces large amounts of heme (iron protoporphyrin) only under low oxygen tensions, such as exist in the symbiotic root nodule. Aerobically incubated suspensions of both laboratory-cultured and symbiotic bacteria (bacteroids) metabolize delta-aminolevulinic acid to uroporphyrin, coproporphyrin, and protoporphyrin. Under anaerobic conditions, suspensions of laboratory-cultured bacteria form greatly reduced amounts of protoporphyrin from delta-aminolevulinic acid, whereas protoporphyrin formation by bacteroid suspensions is unaffected by anaerobiosis, suggesting that bacteroids form protoporphyrin under anaerobic conditions more readily than do free-living bacteria. Oxygen is the major terminal electron acceptor for coproporphyrinogen oxidation in cell-free extracts of both bacteroids and free-living bacteria. In the absence of oxygen, ATP, NADP, Mg2+, and L-methionine are required for protoporphyrin formation in vitro. In the presence of these supplements, coproporphyrinogenase activity under anaerobic conditions is 5 to 10% of that observed under aerobic conditions. Two mechanisms for coproporphyrinogen oxidation exist in R. japonicum: an oxygen-dependent process and an anaerobic oxidation in which electrons are transferred to NADP. The significance of these findings with regard to heme biosynthesis in the microaerophilic soybean root nodule is discussed. PMID:6841317

  17. The formation of flashbulb memories.

    PubMed

    Conway, M A; Anderson, S J; Larsen, S F; Donnelly, C M; McDaniel, M A; McClelland, A G; Rawles, R E; Logie, R H

    1994-05-01

    A large group of subjects took part in a multinational test-retest study to investigate the formation of flashbulb (FB) memories for learning the news of the resignation of the British prime minister, Margaret Thatcher. Over 86% of the U.K. subjects were found to have FB memories nearly 1 year after the resignation; their memory reports were characterized by spontaneous, accurate, and full recall of event details, including minutiae. In contrast, less than 29% of the non-U.K. subjects had FB memories 1 year later; memory reports in this group were characterized by forgetting, reconstructive errors, and confabulatory responses. A causal analysis of secondary variables showed that the formation of FB memories was primarily associated with the level of importance attached to the event and level of affective response to the news. These findings lend some support to the study by R. Brown and Kulik (1977), who suggest that FB memories may constitute a class of autobiographical memories distinguished by some form of preferential encoding.

  18. Virialization Heating in Galaxy Formation

    SciTech Connect

    Wang, P.; Abel, T.

    2007-01-17

    In a hierarchical picture of galaxy formation virialization continually transforms gravitational potential energy into kinetic energies in the baryonic and dark matter. For the gaseous component the kinetic, turbulent energy is transformed eventually into internal thermal energy through shocks and viscous dissipation. Traditionally this virialization and shock heating has been assumed to occur instantaneously allowing an estimate of the gas temperature to be derived from the virial temperature defined from the embedding dark matter halo velocity dispersion. As the mass grows the virial temperature of a halo grows. Mass accretion hence can be translated into a heating term. We derive this heating rate from the extended Press Schechter formalism and demonstrate its usefulness in semi-analytical models of galaxy formation. Our method is preferable to the traditional approaches in which heating from mass accretion is only modeled implicitly through an instantaneous change in virial temperature. Our formalism can trivially be applied in all current semi-analytical models as the heating term can be computed directly from the underlying merger trees. Our analytic results for the first cooling halos and the transition from cold to hot accretion are in agreement with numerical simulations.

  19. Marcelina formation study - Maracaibo basin

    SciTech Connect

    D`Arlach, C.; Peralta, J.; Murillo, R.

    1996-08-01

    Recent development activity onshore, west of the Maracaibo Lake, has led to a better understanding of the Paleocene Marcelina formation in the basin. The Marcelina formation is divided into two sections, an upper coal dominated interval and a lower sand/claystone interval. The sandstone reservoir section consists of a number of fining upward sequences deposited in a fluvial environment. Laterally the section evolves to a shallow marine shaly and carbonatic section, or is truncated by a regional unconformity, being missing over much of the Lake area. The Marcelina sands are only commercially productive in the Alturitas Field, where oil is found in a combined stratigraphic/structural trap. This paper focuses on two aspects of the Marcelina. First, the study incorporates the field data into a regional framework to investigate the possibility of similar plays in the studied area. Second, the study integrates geology and engineering data to examine the Marcelina as a reservoir unit to optimize field development and increase the oil recovery efficiency. Information from seismic, logs, cores, reservoir pressures, and fluids is used to understand the depositional model and the field complexity. The study provides a model, supported by extensive data, which may help to develop other potential discoveries in the west coast area.

  20. Computer simulation of bubble formation.

    SciTech Connect

    Insepov, Z.; Bazhirov, T.; Norman, G.; Stegailov, V.; Mathematics and Computer Science; Institute for High Energy Densities of Joint Institute for High Temperatures of RAS

    2007-01-01

    Properties of liquid metals (Li, Pb, Na) containing nanoscale cavities were studied by atomistic Molecular Dynamics (MD). Two atomistic models of cavity simulation were developed that cover a wide area in the phase diagram with negative pressure. In the first model, the thermodynamics of cavity formation, stability and the dynamics of cavity evolution in bulk liquid metals have been studied. Radial densities, pressures, surface tensions, and work functions of nano-scale cavities of various radii were calculated for liquid Li, Na, and Pb at various temperatures and densities, and at small negative pressures near the liquid-gas spinodal, and the work functions for cavity formation in liquid Li were calculated and compared with the available experimental data. The cavitation rate can further be obtained by using the classical nucleation theory (CNT). The second model is based on the stability study and on the kinetics of cavitation of the stretched liquid metals. A MD method was used to simulate cavitation in a metastable Pb and Li melts and determine the stability limits. States at temperatures below critical (T < 0.5Tc) and large negative pressures were considered. The kinetic boundary of liquid phase stability was shown to be different from the spinodal. The kinetics and dynamics of cavitation were studied. The pressure dependences of cavitation frequencies were obtained for several temperatures. The results of MD calculations were compared with estimates based on classical nucleation theory.

  1. Beaver assisted river valley formation

    USGS Publications Warehouse

    Westbrook, C.J.; Cooper, D.J.; Baker, B.W.

    2011-01-01

    We examined how beaver dams affect key ecosystem processes, including pattern and process of sediment deposition, the composition and spatial pattern of vegetation, and nutrient loading and processing. We provide new evidence for the formation of heterogeneous beaver meadows on riverine system floodplains and terraces where dynamic flows are capable of breaching in-channel beaver dams. Our data show a 1.7-m high beaver dam triggered overbank flooding that drowned vegetation in areas deeply flooded, deposited nutrient-rich sediment in a spatially heterogeneous pattern on the floodplain and terrace, and scoured soils in other areas. The site quickly de-watered following the dam breach by high stream flows, protecting the deposited sediment from future re-mobilization by overbank floods. Bare sediment either exposed by scouring or deposited by the beaver flood was quickly colonized by a spatially heterogeneous plant community, forming a beaver meadow. Many willow and some aspen seedlings established in the more heavily disturbed areas, suggesting the site may succeed to a willow carr plant community suitable for future beaver re-occupation. We expand existing theory beyond the beaver pond to include terraces within valleys. This more fully explains how beavers can help drive the formation of alluvial valleys and their complex vegetation patterns as was first postulated by Ruedemann and Schoonmaker in 1938. ?? 2010 John Wiley & Sons, Ltd.

  2. Vascular pattern formation in plants.

    PubMed

    Scarpella, Enrico; Helariutta, Ykä

    2010-01-01

    Reticulate tissue systems exist in most multicellular organisms, and the principles underlying the formation of cellular networks have fascinated philosophers, mathematicians, and biologists for centuries. In particular, the beautiful and varied arrangements of vascular tissues in plants have intrigued mankind since antiquity, yet the organizing signals have remained elusive. Plant vascular tissues form systems of interconnected cell files throughout the plant body. Vascular cells are aligned with one another along continuous lines, and vascular tissues differentiate at reproducible positions within organ environments. However, neither the precise path of vascular differentiation nor the exact geometry of vascular networks is fixed or immutable. Several recent advances converge to reconcile the seemingly conflicting predictability and plasticity of vascular tissue patterns. A control mechanism in which an apical-basal flow of signal establishes a basic coordinate system for body axis formation and vascular strand differentiation, and in which a superimposed level of radial organizing cues elaborates cell patterns, would generate a reproducible tissue configuration in the context of an underlying robust, self-organizing structure, and account for the simultaneous regularity and flexibility of vascular tissue patterns.

  3. Early phases of star formation

    NASA Astrophysics Data System (ADS)

    Bok, B. J.

    1981-04-01

    Five broad areas of potential star formation in our galaxy and the Magellanic Clouds are presented. The role of gravitational collapse in concentrating matter into eventual stars is examined briefly. The five areas of research are: (1) giant molecular clouds with dimensions of 50 to 100 parsecs and masses equivalent to 100,000 or more suns; (2) the proximity of an H II emission nebula with an embedded or attached cluster of association of O and B stars to a large molecular cloud; (3) the larger so-called globules, notably the roundish and often isolated dark nebulae called Barnard objects, of which 200 or so have been identified within 500 parsecs of the sun; (4) close passage or collisions between interstellar clouds; and (5) supernova explosions. The Large Magellanic Clouds are also examined as an example of an area of potential star formation without the protection of a cosmic dust cloud. Finally, the likelihood that many new stars might possess planets and perhaps even life is discussed.

  4. Possible mechanisms of macrolayer formation

    SciTech Connect

    Sadasivan, P.; Chappidi, P.R.; Unal, C.; Nelson, R.A.

    1992-01-01

    The high heat flux nucleate boiling region, also called the vapor mushroom region, has been shown to have a thin liquid layer on the heater surface under the large mushroom-shaped vapor bubbles that grow from the heater surface. The name given to this liquid layer is the macrolayer to differentiate it from the microlayer that exists under the discrete bubbles found at lower heat fluxes in the nucleate boiling region. Typical thicknesses of this macrolayer range from 50 to 500 {mu}m for water on a flat horizontal boiling surface and depend upon the heat flux. Thus, the macrolayer is thicker than the wedge-shaped microlayers, found under discrete bubbles, which range in thickness from 1 to 10 {mu}m. Although the mechanism of microlayer formation and its evaporation is conceptually simple that of the macrolayer is still not understood. This paper critically compares the potential mechanisms proposed for macrolayer formation. These mechanisms include the Helmholtz instability applied to the vapor stem above active nucleation sites, liquid trapped by lateral coalescence of discrete bubbles that initially form during the mushroom bubble's waiting period, and the limitation of liquid resupply at mushroom departure as a result of vapor flow from the active nucleation sites.

  5. Possible mechanisms of macrolayer formation

    SciTech Connect

    Sadasivan, P.; Chappidi, P.R.; Unal, C.; Nelson, R.A.

    1992-05-01

    The high heat flux nucleate boiling region, also called the vapor mushroom region, has been shown to have a thin liquid layer on the heater surface under the large mushroom-shaped vapor bubbles that grow from the heater surface. The name given to this liquid layer is the macrolayer to differentiate it from the microlayer that exists under the discrete bubbles found at lower heat fluxes in the nucleate boiling region. Typical thicknesses of this macrolayer range from 50 to 500 {mu}m for water on a flat horizontal boiling surface and depend upon the heat flux. Thus, the macrolayer is thicker than the wedge-shaped microlayers, found under discrete bubbles, which range in thickness from 1 to 10 {mu}m. Although the mechanism of microlayer formation and its evaporation is conceptually simple that of the macrolayer is still not understood. This paper critically compares the potential mechanisms proposed for macrolayer formation. These mechanisms include the Helmholtz instability applied to the vapor stem above active nucleation sites, liquid trapped by lateral coalescence of discrete bubbles that initially form during the mushroom bubble`s waiting period, and the limitation of liquid resupply at mushroom departure as a result of vapor flow from the active nucleation sites.

  6. Enamel formation and amelogenesis imperfecta.

    PubMed

    Hu, Jan C-C; Chun, Yong-Hee P; Al Hazzazzi, Turki; Simmer, James P

    2007-01-01

    Dental enamel is the epithelial-derived hard tissue covering the crowns of teeth. It is the most highly mineralized and hardest tissue in the body. Dental enamel is acellular and has no physiological means of repair outside of the protective and remineralization potential provided by saliva. Enamel is comprised of highly organized hydroxyapatite crystals that form in a defined extracellular space, the contents of which are supplied and regulated by ameloblasts. The entire process is under genetic instruction. The genetic control of amelogenesis is poorly understood, but requires the activities of multiple components that are uniquely important for dental enamel formation. Amelogenesis imperfecta (AI) is a collective designation for the variety of inherited conditions displaying isolated enamel malformations, but the designation is also used to indicate the presence of an enamel phenotype in syndromes. Recently, genetic studies have demonstrated the importance of genes encoding enamel matrix proteins in the etiology of isolated AI. Here we review the essential elements of dental enamel formation and the results of genetic analyses that have identified disease-causing mutations in genes encoding enamel matrix proteins. In addition, we provide a fresh perspective on the roles matrix proteins play in catalyzing the biomineralization of dental enamel.

  7. Autophagosome formation in mammalian cells.

    PubMed

    Burman, Chloe; Ktistakis, Nicholas T

    2010-12-01

    Autophagy is a fundamental intracellular trafficking pathway conserved from yeast to mammals. It is generally thought to play a pro-survival role, and it can be up regulated in response to both external and intracellular factors, including amino acid starvation, growth factor withdrawal, low cellular energy levels, endoplasmic reticulum (ER) stress, hypoxia, oxidative stress, pathogen infection, and organelle damage. During autophagy initiation a portion of the cytosol is surrounded by a flat membrane sheet known as the isolation membrane or phagophore. The isolation membrane then elongates and seals itself to form an autophagosome. The autophagosome fuses with normal endocytic traffic to mature into a late autophagosome, before fusing with lysosomes. The molecular machinery that enables formation of an autophagosome in response to the various autophagy stimuli is almost completely identified in yeast and-thanks to the observed conservation-is also being rapidly elucidated in higher eukaryotes including mammals. What are less clear and currently under intense investigation are the mechanism by which these various autophagy components co-ordinate in order to generate autophagosomes. In this review, we will discuss briefly the fundamental importance of autophagy in various pathophysiological states and we will then review in detail the various players in early autophagy. Our main thesis will be that a conserved group of heteromeric protein complexes and a relatively simple signalling lipid are responsible for the formation of autophagosomes in mammalian cells.

  8. Coring in deep hardrock formations

    SciTech Connect

    Drumheller, D.S.

    1988-08-01

    The United States Department of Energy is involved in a variety of scientific and engineering feasibility studies requiring extensive drilling in hard crystalline rock. In many cases well depths extend from 6000 to 20,000 feet in high-temperature, granitic formations. Examples of such projects are the Hot Dry Rock well system at Fenton Hill, New Mexico and the planned exploratory magma well near Mammoth Lakes, California. In addition to these programs, there is also continuing interest in supporting programs to reduce drilling costs associated with the production of geothermal energy from underground sources such as the Geysers area near San Francisco, California. The overall progression in these efforts is to drill deeper holes in higher temperature, harder formations. In conjunction with this trend is a desire to improve the capability to recover geological information. Spot coring and continuous coring are important elements in this effort. It is the purpose of this report to examine the current methods used to obtain core from deep wells and to suggest projects which will improve existing capabilities. 28 refs., 8 figs., 2 tabs.

  9. BAR FORMATION FROM GALAXY FLYBYS

    SciTech Connect

    Lang, Meagan; Holley-Bockelmann, Kelly; Sinha, Manodeep E-mail: k.holley@vanderbilt.edu

    2014-08-01

    Recently, both simulations and observations have revealed that flybys—fast, one-time interactions between two galaxy halos—are surprisingly common, nearing/comparable to galaxy mergers. Since these are rapid, transient events with the closest approach well outside the galaxy disk, it is unclear if flybys can transform the galaxy in a lasting way. We conduct collisionless N-body simulations of three coplanar flyby interactions between pure-disk galaxies to take a first look at the effects flybys have on disk structure, with particular focus on stellar bar formation. We find that some flybys are capable of inciting a bar with bars forming in both galaxies during our 1:1 interaction and in the secondary during our 10:1 interaction. The bars formed have ellipticities ≳ 0.5, sizes on the order of the host disk's scale length, and persist to the end of our simulations, ∼5 Gyr after pericenter. The ability of flybys to incite bar formation implies that many processes associated with secular bar evolution may be more closely tied with interactions than previously thought.

  10. Protostellar formation in rotating interstellar clouds. VIII - Inner core formation

    NASA Technical Reports Server (NTRS)

    Boss, Alan P.

    1989-01-01

    The results are presented of a variety of spherically symmetric one-dimensional (1D) calculations intended to determine the robustness of the dynamical hiccup phenomenon in protostellar cores. The 1D models show that the phenomenon is relatively insensitive to changes in the equations of state, numerical resolution, initial density and temperature, and the radiative transfer approximation. In 1D, the hiccup results in an explosive destruction of the entire inner protostellar core. Inner core formation is studied with a sequence of three-dimensional models which show that rapid inner core rotation stabilizes the hiccup instability. Instead, the inner core becomes quite flat and undergoes a cycle of binary fragmentation, binary decay into a single object surrounded by a bar, breakup of the bar into a binary, etc. When lesser amounts of rotation are involved, the inner core does hiccup somewhat, but mass is ejected in only a few directions, leading to several broad streams of ejecta.

  11. Treating nahcolite containing formations and saline zones

    DOEpatents

    Vinegar, Harold J

    2013-06-11

    A method for treating a nahcolite containing subsurface formation includes removing water from a saline zone in or near the formation. The removed water is heated using a steam and electricity cogeneration facility. The heated water is provided to the nahcolite containing formation. A fluid is produced from the nahcolite containing formation. The fluid includes at least some dissolved nahcolite. At least some of the fluid is provided to the saline zone.

  12. A new PICL trace file format

    SciTech Connect

    Worley, P.H.

    1992-10-01

    A trace file format is described that will be used in future releases of the Portable Instrumented Communication Library (PICL) and ParaGraph. The new format provides improved support for tracing and profiling PICL communication primitives and user-defined events. The new format is also easily extended and may be useful in other instrumentation packages and performance visualization tools.

  13. Spiritual Formation within Christian Higher Education

    ERIC Educational Resources Information Center

    Otto, Patrick; Harrington, Michael

    2016-01-01

    The Christian university has a distinct responsibility to provide an environment devoted to the spiritual formation of students. Spiritual formation is not to be viewed as the only important goal of the university, thereby sacrificing intellectual or relational development, but rather spiritual formation is the aggregate "product" of the…

  14. Formative Assessment: Policy, Perspectives and Practice

    ERIC Educational Resources Information Center

    Clark, Ian

    2011-01-01

    Proponents of formative assessment (FA) assert that students develop a deeper understanding of their learning when the essential components of formative feedback and cultural responsiveness are effectively incorporated as central features of the formative assessment process. Even with growing international agreement among the research community…

  15. Formative Assessment: Guidance for Early Childhood Policymakers

    ERIC Educational Resources Information Center

    Riley-Ayers, Shannon

    2014-01-01

    This policy report provides a guide and framework to early childhood policymakers considering formative assessment. The report defines formative assessment and outlines its process and application in the context of early childhood. The substance of this document is the issues for consideration in the implementation of the formative assessment…

  16. 21 CFR 186.1756 - Sodium formate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ....1756 Sodium formate. (a) Sodium formate (CHNaO2, CAS Reg. No. 141-53-7) is the sodium salt of formic acid. It is produced by the reaction of carbon monoxide with sodium hydroxide. (b) The ingredient is... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Sodium formate. 186.1756 Section 186.1756 Food...

  17. Successful Student Writing through Formative Assessment

    ERIC Educational Resources Information Center

    Tuttle, Harry Grover

    2010-01-01

    Use formative assessment to dramatically improve your students' writing. In "Successful Student Writing Through Formative Assessment", educator and international speaker Harry G. Tuttle shows you how to guide middle and high school students through the prewriting, writing, and revision processes using formative assessment techniques that work.…

  18. 7 CFR 1755.407 - Data formats.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 11 2013-01-01 2013-01-01 false Data formats. 1755.407 Section 1755.407 Agriculture... TELECOMMUNICATIONS POLICIES ON SPECIFICATIONS, ACCEPTABLE MATERIALS, AND STANDARD CONTRACT FORMS § 1755.407 Data formats. The following suggested formats listed in this section may be used for recording the test...

  19. 7 CFR 1755.407 - Data formats.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 11 2014-01-01 2014-01-01 false Data formats. 1755.407 Section 1755.407 Agriculture... TELECOMMUNICATIONS POLICIES ON SPECIFICATIONS, ACCEPTABLE MATERIALS, AND STANDARD CONTRACT FORMS § 1755.407 Data formats. The following suggested formats listed in this section may be used for recording the test...

  20. 7 CFR 1755.407 - Data formats.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 11 2011-01-01 2011-01-01 false Data formats. 1755.407 Section 1755.407 Agriculture... TELECOMMUNICATIONS POLICIES ON SPECIFICATIONS, ACCEPTABLE MATERIALS, AND STANDARD CONTRACT FORMS § 1755.407 Data formats. The following suggested formats listed in this section may be used for recording the test...

  1. 7 CFR 1755.407 - Data formats.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 11 2010-01-01 2010-01-01 false Data formats. 1755.407 Section 1755.407 Agriculture... TELECOMMUNICATIONS POLICIES ON SPECIFICATIONS, ACCEPTABLE MATERIALS, AND STANDARD CONTRACT FORMS § 1755.407 Data formats. The following suggested formats listed in this section may be used for recording the test...

  2. 7 CFR 1755.407 - Data formats.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 11 2012-01-01 2012-01-01 false Data formats. 1755.407 Section 1755.407 Agriculture... TELECOMMUNICATIONS POLICIES ON SPECIFICATIONS, ACCEPTABLE MATERIALS, AND STANDARD CONTRACT FORMS § 1755.407 Data formats. The following suggested formats listed in this section may be used for recording the test...

  3. Composition and method of stimulating subterranean formations

    SciTech Connect

    Dill, W.R.; Walker, M.L.; Ford, G.F.

    1987-07-14

    This patent describes a method of treating a subterranean formation containing iron comprising contacting a subterranean formation with an aqueous fluid containing a compound consisting essentially of at least one member selected from the group consisting of: dihydroxymaleic acid, salts of dihydroxymaleic acid, glucono-deltalactone present in an amount sufficient to prevent the precipitation of ferric iron during contact with the subterranean formation.

  4. Formative Constructs Implemented via Common Factors

    ERIC Educational Resources Information Center

    Treiblmaier, Horst; Bentler, Peter M.; Mair, Patrick

    2011-01-01

    Recently there has been a renewed interest in formative measurement and its role in properly specified models. Formative measurement models are difficult to identify, and hence to estimate and test. Existing solutions to the identification problem are shown to not adequately represent the formative constructs of interest. We propose a new two-step…

  5. String Formatting Considered Harmful for Novice Programmers

    ERIC Educational Resources Information Center

    Hughes, Michael C.; Jadud, Matthew C.; Rodrigo, Ma. Mercedes T.

    2010-01-01

    In Java, "System.out.printf" and "String.format" consume a specialised kind of string commonly known as a format string. In our study of first-year students at the Ateneo de Manila University, we discovered that format strings present a substantial challenge for novice programmers. Focusing on their first laboratory we found that 8% of all the…

  6. Diet History Questionnaire II: Size Formats

    Cancer.gov

    Two serving size formats are used on the NCI versions of the DHQ as shown below. Format 1 is used for nearly all serving size questions. Format 2 is used only in special cases, where 'never' is allowed as a response.

  7. Micelle Formation in Liquid Ammonia.

    PubMed

    Griffin, Joseph M; Atherton, John H; Page, Michael I

    2015-07-17

    Perfluorinated long chain alkyl amides aggregate in liquid ammonia with increasing concentration which reflects micelle-type formation based on changes in (19)F NMR chemical shifts. The critical micelle concentrations (cmc) decrease with increasing chain length and give Kleven parameters A = 0.18 and B = 0.19. The micelles catalyze the ammonolysis of esters in liquid ammonia. The corresponding perfluorinated long chain alkyl carboxylates form ion pairs in liquid ammonia, but the equilibrium dissociation constants indicate favorable interactions between the chains in addition to the electrostatic forces. These perfluorinated carboxylates form micelles in aqueous solution, and their cmc's generate a Kleven B-value = 0.52 compared with 0.30 for the analogous alkyl carboxylates. The differences in hydrophobicity of CH2 and CF2 units in water and liquid ammonia are discussed, as is the possible relevance to life forms in liquid ammonia.

  8. Engineering Model for Ash Formation

    1994-12-02

    Ash deposition is controlled by the impaction and sticking of individual ash particles to heat transfer surfaces. Prediction of deposition therefore requires that the important factors in this process be predictable from coal and operational parameters. Coal combustion, boiler heat transfer, ash formation, ash particle aerodynamic, and ash particle sticking models are all essential steps in this process. The model described herein addresses the prediction of ash particle size and composition distributions based upon combustionmore » conditions and coal parameters. Key features of the model include a mineral redistribution routine to invert CCSEM mineralogical data, and a mineral interaction routine that simulates the conversion of mineral matter into ash during coal burning and yields ash particle size and composition distributions.« less

  9. Eyeblinks in formation of impressions.

    PubMed

    Omori, Y; Miyata, Y

    1996-10-01

    The purpose of this study was to investigate the influence of frequency of one's eyeblinks on creating a personal impression. The subjects, 102 males and 127 females, ages 15 to 60 years, rated on a 7-point semantic differential scale a rarely blinking person or a frequently blinking person described on a question-sheet. A factor analysis of the ratings yielded three factors, interpreted as Nervousness, Unfriendliness, and Lack of intelligence. The frequently blinking person was rated as more nervous and less intelligent than the rarely blinking person. Present results provided evidence that frequency of eyeblinks may play an important role on the formation of impressions. Further implications of the findings are discussed. PMID:8902035

  10. Crystal formation in furunculosis agar

    USGS Publications Warehouse

    Bullock, G.L.; Ross, A.J.

    1964-01-01

    SINCE ITS INTRODUCTION SOME MONTHS AGO, FURUNCULOSIS AGAR has been employed in the diagnosis of suspect furunculosis and also as a general purpose medium. During our work with this medium we have noticed discrete "colonies," of crystalline material, which very closely resemble microbial colonies. These crystal colonies are compact and appear on both the surface and subsurface; they occur in inoculated slants and plates incubated for long periods (2 to 3 weeks), as well as in uninoculated stored medium. As the crystal colonies could be confusing to workers using this medium, we decided to attempt to identify them and also to determine whether storage conditions and different lots of medium affect crystal formation.

  11. Foam formation in low gravity

    NASA Technical Reports Server (NTRS)

    Wessling, Francis C.; Mcmanus, Samuel P.; Matthews, John; Patel, Darayas

    1990-01-01

    An apparatus that produced the first polyurethane foam in low gravity has been described. The chemicals were mixed together in an apparatus designed for operation in low gravity. Mixing was by means of stirring the chemicals with an electric motor and propeller in a mixing chamber. The apparatus was flown on Consort 1, the first low-gravity materials payload launched by a commercial rocket launch team. The sounding rocket flight produced over 7 min of low gravity during which a polyurethane spheroidal foam of approximately 2300 cu cm was formed. Photographs of the formation of the foam during the flight show the development of the spheroidal form. This begins as a small sphere and grows to approximately a 17-cm-diam spheroid. The apparatus will be flown again on subsequent low-gravity flights.

  12. Mud Volcanoes Formation And Occurrence

    NASA Astrophysics Data System (ADS)

    Guliyev, I. S.

    2007-12-01

    Mud volcanoes are natural phenomena, which occur throughout the globe. They are found at a greater or lesser scale in Azerbaijan, Turkmenistan, Georgia, on the Kerch and Taman peninsulas, on Sakhalin Island, in West Kuban, Italy, Romania, Iran, Pakistan, India, Burma, China, Japan, Indonesia, Malaysia, New Zealand, Mexico, Colombia, Trinidad and Tobago, Venezuela and Ecuador. Mud volcanoes are most well-developed in Eastern Azerbaijan, where more than 30% of all the volcanoes in the world are concentrated. More than 300 mud volcanoes have already been recognized here onshore or offshore, 220 of which lie within an area of 16,000 km2. Many of these mud volcanoes are particularly large (up to 400 m high). The volcanoes of the South Caspian form permanent or temporary islands, and numerous submarine banks. Many hypotheses have been developed regarding the origin of mud volcanoes. Some of those hypotheses will be examined in the present paper. Model of spontaneous excitation-decompaction (proposed by Ivanov and Guliev, 1988, 2002). It is supposed that one of major factors of the movement of sedimentary masses and formation of hydrocarbon deposits are phase transitions in sedimentary basin. At phase transitions there are abnormal changes of physical and chemical parameters of rocks. Abnormal (high and negative) pressure takes place. This process is called as excitation of the underground environment with periodicity from several tens to several hundreds, or thousand years. The relationship between mud volcanism and the generation of hydrocarbons, particularly methane, is considered to be a critical factor in mud volcano formation. At high flow rates the gas and sediment develops into a pseudo-liquid state and as flow increases the mass reaches the "so-called hover velocity" where mass transport begins. The mass of fluid moves as a quasi-uniform viscous mass through the sediment pile in a piston like manner until expelled from the surface as a "catastrophic eruption

  13. On the formation of granulites

    USGS Publications Warehouse

    Bohlen, S.R.

    1991-01-01

    The tectonic settings for the formation and evolution of regional granulite terranes and the lowermost continental crust can be deduced from pressure-temperature-time (P-T-time) paths and constrained by petrological and geophysical considerations. P-T conditions deduced for regional granulites require transient, average geothermal gradients of greater than 35??C km-1, implying minimum heat flow in excess of 100 mW m-2. Such high heat flow is probably caused by magmatic heating. Tectonic settings wherein such conditions are found include convergent plate margins, continental rifts, hot spots and at the margins of large, deep-seated batholiths. Cooling paths can be constrained by solid-solid and devolatilization equilibria and geophysical modelling. -from Author

  14. Macromolecules Relevant to Stone Formation

    NASA Astrophysics Data System (ADS)

    Ryall, Rosemary L.; Cook, Alison F.; Thurgood, Lauren A.; Grover, Phulwinder K.

    2007-04-01

    Despite years of research, no single macromolecule in kidney calculi or in urine has yet been shown to fulfill a specific function in stone pathogenesis. In this paper we briefly review papers investigating the urinary excretion of individual macromolecules, their effects on calcium oxalate (CaOx) crystallization and attachment of crystals to renal epithelial cells, and the influence of lithogenic conditions on their renal expression in cultured cells and animal models. Using prothrombin fragment 1 (PTF1) and human serum albumin as examples, we show the types of patterns resulting from the binding of a fluorescently tagged protein to a specific CaOx monohydrate (COM) crystal face and its incorporation into the crystal structure. Molecular modeling is also used to illustrate how PTF1 can align with the atomic array on a COM crystal surface. We conclude that although many macromolecules are, by strict definition, relevant to stone formation, very few are probably truly influential.

  15. Polar Cap Formation on Ganymede

    NASA Technical Reports Server (NTRS)

    Pilcher, C. B.; Shaya, E. J.

    1985-01-01

    Since thermal migration is not an effective mechanism for water transport in the polar regions at the Galilean satellites, some other process must be responsible for the formation of Ganymede's polar caps. It is proposed that Ganymede's polar caps are the optical manifestation of a process that began with the distribution of an ice sheet over the surface of Ganymede. The combined processes of impact gardening and thermal migration led, in regions at latitudes less than 40 to 45 deg., to the burial of some fraction of this ice, the migration of some to the polar caps margins, and a depletion of free ice in the optical surface. At higher latitudes, no process was effective in removing ice from the optical surface, so the remanants of the sheet are visible today.

  16. Combuster. [low nitrogen oxide formation

    NASA Technical Reports Server (NTRS)

    Mckay, R. A. (Inventor)

    1978-01-01

    A combuster is provided for utilizing a combustible mixture containing fuel and air, to heat a load fluid such as water or air, in a manner that minimizes the formation of nitrogen oxide. The combustible mixture passes through a small diameter tube where the mixture is heated to its combustion temperature, while the load fluid flows past the outside of the tube to receive heat. The tube is of a diameter small enough that the combustible mixture cannot form a flame, and yet is not subject to wall quench, so that combustion occurs, but at a temperature less than under free flame conditions. Most of the heat required for heating the combustible mixture to its combustion temperature, is obtained from heat flow through the walls of the pipe to the mixture.

  17. The Science of Galaxy Formation

    NASA Astrophysics Data System (ADS)

    Gilmore, Gerard

    2009-03-01

    Our knowledge of the Universe remains discovery-led: in the absence of adequate physics-based theory, interpretation of new results requires a scientific methodology. Commonly, scientific progress in astrophysics is motivated by the empirical success of the “Copernican Principle”, that the simplest and most objective analysis of observation leads to progress. A complementary approach tests the prediction of models against observation. In practise, astrophysics has few real theories, and has little control over what we can observe. Compromise is unavoidable. Advances in understanding complex non-linear situations, such as galaxy formation, require that models attempt to isolate key physical properties, rather than trying to reproduce complexity. A specific example is discussed, where substantial progress in fundamental physics could be made with an ambitious approach to modelling: simulating the spectrum of perturbations on small scales.

  18. Electrochemical formation of field emitters

    DOEpatents

    Bernhardt, A.F.

    1999-03-16

    Electrochemical formation of field emitters, particularly useful in the fabrication of flat panel displays is disclosed. The fabrication involves field emitting points in a gated field emitter structure. Metal field emitters are formed by electroplating and the shape of the formed emitter is controlled by the potential imposed on the gate as well as on a separate counter electrode. This allows sharp emitters to be formed in a more inexpensive and manufacturable process than vacuum deposition processes used at present. The fabrication process involves etching of the gate metal and the dielectric layer down to the resistor layer, and then electroplating the etched area and forming an electroplated emitter point in the etched area. 12 figs.

  19. Statoconia formation in molluscan statocysts

    NASA Technical Reports Server (NTRS)

    Wiederhold, M. L.; Sheridan, C. E.; Smith, N. K.

    1986-01-01

    The gravity sensors of all molluscs phylogenetically below the cephalopods are spherical organs called statocysts. The wall of the sphere contains mechanosensory cells whose sensory cilia project into the lumen of the cyst. The lumen is filled with fluid and dense "stones", the statoconia or statoliths, which sink under the influence of gravity to load, and stimulate, those receptor cells which are at the bottom. The statoconia of Aplysia californica are shown to be calcified about a lamellar arrangement of membranes. Similar lamellar membrane arrangements are seen within the receptor cells, and their possible role in the formation of the statoconia is discussed. SEM of unfixed statoconia reveals plate-like crystallization on their surface. Elemental analysis shows a relatively high Sr content, which is of interest, since others have recently reported that Sr is required in the culture medium of several laboratory reared molluscs in order for the statoconia to develop.

  20. Polar frost formation on Ganymede

    NASA Technical Reports Server (NTRS)

    Johnson, R. E.

    1985-01-01

    Voyager photographs have shown the presence of polar frost on Ganymede, a satellite of Jupiter. A number of models have been proposed for the formation of this feature. The models are based on the transport of material from the equatorial to the polar regions. The present paper is concerned with a model regarding the origin and appearance of the Ganymede caps which does not depend on such a transport. The model is based on observations of the surficial changes produced by ion bombardment. It is pointed out that experiments on ion and electron bombardment of water ice at low temperatures have shown that these particles sputter significant quantities of water molecules. In addition, they also change the visual characteristics of the surface significantly. Ion bombardment competing with thermal reprocessing may be sufficient to explain the latitudinal differences observed on Ganymede.

  1. Butanol formation from gaseous substrates.

    PubMed

    Dürre, Peter

    2016-03-01

    Mostly, butanol is formed as a product by saccharolytic anaerobes, employing the so-called ABE fermentation (for acetone-butanol-ethanol). However, this alcohol can also be produced from gaseous substrates such as syn(thesis) gas (major components are carbon monoxide and hydrogen) by autotrophic acetogens. In view of economic considerations, a biotechnological process based on cheap and abundant gases such as CO and CO2 as a carbon source is preferable to more expensive sugar or starch fermentation. In addition, any conflict for use of substrates that can also serve as human nutrition is avoided. Natural formation of butanol has been found with, e.g. Clostridium carboxidivorans, while metabolic engineering for butanol production was successful using, e.g. C. ljungdahlii. Production of butanol from CO2 under photoautotrophic conditions was also possible by recombinant DNA construction of a respective cyanobacterial Synechococcus sp. PCC 7942 strain. PMID:26903012

  2. Heating tar sands formations while controlling pressure

    DOEpatents

    Stegemeier, George Leo [Houston, TX; Beer, Gary Lee [Houston, TX; Zhang, Etuan [Houston, TX

    2010-01-12

    Methods for treating a tar sands formation are described herein. Methods may include heating at least a section of a hydrocarbon layer in the formation from a plurality of heaters located in the formation. A pressure in the majority of the section may be maintained below a fracture pressure of the formation. The pressure in the majority of the section may be reduced to a selected pressure after the average temperature reaches a temperature that is above 240.degree. C. and is at or below pyrolysis temperatures of hydrocarbons in the section. At least some hydrocarbon fluids may be produced from the formation.

  3. Engram formation in psychiatric disorders

    PubMed Central

    Gebicke-Haerter, Peter J.

    2014-01-01

    Environmental factors substantially influence beginning and progression of mental illness, reinforcing or reducing the consequences of genetic vulnerability. Often initiated by early traumatic events, “engrams” or memories are formed that may give rise to a slow and subtle progression of psychiatric disorders. The large delay between beginning and time of onset (diagnosis) may be explained by efficient compensatory mechanisms observed in brain metabolism that use optional pathways in highly redundant molecular interactions. To this end, research has to deal with mechanisms of learning and long-term memory formation, which involves (a) epigenetic changes, (b) altered neuronal activities, and (c) changes in neuron-glia communication. On the epigenetic level, apparently DNA-methylations are more stable than histone modifications, although both closely interact. Neuronal activities basically deliver digital information, which clearly can serve as basis for memory formation (LTP). However, research in this respect has long time neglected the importance of glia. They are more actively involved in the control of neuronal activities than thought before. They can both reinforce and inhibit neuronal activities by transducing neuronal information from frequency-encoded to amplitude and frequency-modulated calcium wave patterns spreading in the glial syncytium by use of gap junctions. In this way, they serve integrative functions. In conclusion, we are dealing with two concepts of encoding information that mutually control each other and synergize: a digital (neuronal) and a wave-like (glial) computing, forming neuron-glia functional units with inbuilt feedback loops to maintain balance of excitation and inhibition. To better understand mental illness, we have to gain more insight into the dynamics of adverse environmental impact on those cellular and molecular systems. This report summarizes existing knowledge and draws some outline about further research in molecular

  4. Biomineralization: mineral formation by organisms

    NASA Astrophysics Data System (ADS)

    Addadi, Lia; Weiner, Steve

    2014-09-01

    Organisms form many different types of minerals, with diverse shapes and sizes. These minerals fulfill a variety of functions. Inspired by the late H A Lowenstam, Steve Weiner and Lia Addadi have addressed many questions that relate to the mechanisms by which biological organisms produce these mineral phases and how their structures relate to their functions. Addadi and Weiner have explored the manner in which macromolecules extracted from mineralized tissues can interact with some crystal planes and not others, how these macromolecules can be occluded inside the forming crystals residing preferentially on specific crystal planes, and how they can induce one polymorph of calcium carbonate and not another to nucleate. Addadi and Weiner have also identified a novel strategy used by the sea urchin to form its smooth and convoluted mineralized skeletal elements. The strategy involves the initial production by cells of a highly disordered mineral precursor phase in vesicles, and then the export of this so-called amorphous phase to the site of skeletal formation, where it crystallizes. This strategy is now known to be used by many different invertebrate phyla, as well as by vertebrates to build bones and teeth. One of the major current research aims of the Weiner--Addadi group is to understand the biomineralization pathways whereby ions are extracted from the environment, are transported and deposited inside cells within vesicles, how these disordered phases are then transferred to the site of skeletal formation, and finally how the so-called amorphous phase crystallizes. Biology has clearly evolved unique strategies for forming crystalline minerals. Despite more than 300 years of research in this field, many challenging questions still remain unanswered.

  5. Drill cuttings mount formation study

    NASA Astrophysics Data System (ADS)

    Teh, Su Yean; Koh, Hock Lye

    2014-07-01

    Oil, Gas and Energy sector has been identified as an essential driving force in the Malaysian Economic Transformation Programs (ETP). Recently confirmed discovery of many offshore oil and gas deposits in Malaysian waters has ignited new confidence in this sector. However, this has also spurred intense interest on safeguarding the health and environment of coastal waters in Malaysia from adverse impact resulting from offshore oil and gas production operation. Offshore discharge of spent drilling mud and rock cuttings is the least expensive and simplest option to dispose of large volumes of drilling wastes. But this onsite offshore disposal may have adverse environmental impacts on the water column and the seabed. It may also pose occupational health hazards to the workers living in the offshore platforms. It is therefore important to model the transport and deposition of drilling mud and rock cuttings in the sea to enable proper assessment of their adverse impacts on the environment and the workers. Further, accumulation of drill particles on the seabed may impede proper operation of pipelines on the seabed. In this paper, we present an in-house application model TUNA-PT developed to cater to local oil and gas industry needs to simulate the dispersion and mount formation of drill cuttings by offshore oil and gas exploration and production platforms. Using available data on Malaysian coastal waters, simulation analyses project a pile formation on the seabed with a maximum height of about 1 m and pile radius of around 30 to 50 m. Simulated pile heights are not sensitive to the heights of release of the cuttings as the sensitivity has been mitigated by the depth of water.

  6. Formation and Evolution of Protoatmospheres

    NASA Astrophysics Data System (ADS)

    Massol, H.; Hamano, K.; Tian, F.; Ikoma, M.; Abe, Y.; Chassefière, E.; Davaille, A.; Genda, H.; Güdel, M.; Hori, Y.; Leblanc, F.; Marcq, E.; Sarda, P.; Shematovich, V. I.; Stökl, A.; Lammer, H.

    2016-09-01

    The origin and evolution of planetary protoatmospheres in relation to the protoplanetary disk is discussed. The initial atmospheres of planets can mainly be related via two formation scenarios. If a protoplanetary core accretes mass and grows inside the gas disk, it can capture H2, He and other gases from the disk. When the gas of the disk evaporates, the core that is surrounded by the H2/He gas envelope is exposed to the high X-ray and extreme ultraviolet flux and stellar wind of the young host star. This period can be considered as the onset of atmospheric escape. It is shown that lower mass bodies accrete less gas and depending on the host stars radiation environment can therefore lose the gaseous envelope after tens or hundreds of million years. Massive cores may never get rid of their captured hydrogen envelopes and remain as sub-Neptunes, Neptunes or gas giants for their whole life time. Terrestrial planets which may have lost the captured gas envelope by thermal atmospheric escape, or which accreted after the protoplanetary nebula vanished will produce catastrophically outgassed steam atmospheres during the magma ocean solidification process. These steam atmospheres consist mainly of water and CO2 that was incorporated into the protoplanet during its accretion. Planets, which are formed in the habitable zone, solidify within several million years. In such cases the outgassed steam atmospheres cool fast, which leads to the condensation of water and the formation of liquid oceans. On the other hand, magma oceans are sustained for longer if planets form inside a critical distance, even if they outgassed a larger initial amount of water. In such cases the steam atmosphere could remain 100 million years or for even longer. Hydrodynamic atmospheric escape will then desiccate these planets during the slow solidification process.

  7. Transmissivity of a heterogeneous formation

    NASA Astrophysics Data System (ADS)

    Dykaar, Bruce B.; Kitanidis, Peter K.

    1993-04-01

    The objective of this paper is to derive the transmissivity of an equivalent homogeneous medium having the same macroscopic flow behavior as the actual heterogeneous formation. We apply generalized Taylor-Ans moment analysis in order to determine the phenomenological coefficient of transmissivity for the case of saturated flow confined in a heterogeneous permeable formation with variable thickness. The generalized Taylor-Aris moment analysis yields a two-step procedure for determining the constant two-dimensional transmissivity tensor from the three-dimensional spatially variable conductivity tensor: solve a flow problem and then perform an integration. For the special case that the conductivity is locally isotropic and the impermeable confining surfaces are parallel, the equations governing transmissivity are discretized using a pseudospectral Fourier-Galerkin scheme. The resultant system of linear algebraic equations is solved efficiently, using preconditioned conjugate gradients, in order Nt In (Nt) operations, where Nt is the number of spatial discretization points. The numerical method is used in several examples to compute the transmissivity of lognormally distributed hydraulic conductivity, and the results are compared with the transmissivity found using the usual depth-averaging approach and another method suggested in the literature. The numerical results show that the averaging volume required to obtain an effective value of transmissivity is about 10 horizontal integral scales. When the flow field has a significant three-dimensional character, the standard method of finding transmissivities by depth averaging can lead to significant errors in the prediction of global scale flows. It is shown that depth averaging consistently overestimates transmissivities. An example illustrates how in the case of tilted strata, anisotropic transmissivities arise and how the degree of transmissivity anisotropy depends on the angle of the dip and the horizontal to

  8. Multimap formation in visual cortex

    PubMed Central

    Jain, Rishabh; Millin, Rachel; Mel, Bartlett W.

    2015-01-01

    An extrastriate visual area such as V2 or V4 contains neurons selective for a multitude of complex shapes, all sharing a common topographic organization. Simultaneously developing multiple interdigitated maps—hereafter a “multimap”—is challenging in that neurons must compete to generate a diversity of response types locally, while cooperating with their dispersed same-type neighbors to achieve uniform visual field coverage for their response type at all orientations, scales, etc. Previously proposed map development schemes have relied on smooth spatial interaction functions to establish both topography and columnar organization, but by locally homogenizing cells' response properties, local smoothing mechanisms effectively rule out multimap formation. We found in computer simulations that the key requirements for multimap development are that neurons are enabled for plasticity only within highly active regions of cortex designated “learning eligibility regions” (LERs), but within an LER, each cell's learning rate is determined only by its activity level with no dependence on location. We show that a hybrid developmental rule that combines spatial and activity-dependent learning criteria in this way successfully produces multimaps when the input stream contains multiple distinct feature types, or in the degenerate case of a single feature type, produces a V1-like map with “salt-and-pepper” structure. Our results support the hypothesis that cortical maps containing a fine mixture of different response types, whether in monkey extrastriate cortex, mouse V1 or elsewhere in the cortex, rather than signaling a breakdown of map formation mechanisms at the fine scale, are a product of a generic cortical developmental scheme designed to map cells with a diversity of response properties across a shared topographic space. PMID:26641946

  9. Formation Flying for Distributed InSAR

    NASA Technical Reports Server (NTRS)

    Scharf, Daniel P.; Murray, Emmanuell A.; Ploen, Scott R.; Gromov, Konstantin G.; Chen, Curtis W.

    2006-01-01

    We consider two spacecraft flying in formation to create interferometric synthetic aperture radar (InSAR). Several candidate orbits for such in InSar formation have been previously determined based on radar performance and Keplerian orbital dynamics. However, with out active control, disturbance-induced drift can degrade radar performance and (in the worst case) cause a collision. This study evaluates the feasibility of operating the InSAR spacecraft as a formation, that is, with inner-spacecraft sensing and control. We describe the candidate InSAR orbits, design formation guidance and control architectures and algorithms, and report the (Delta)(nu) and control acceleration requirements for the candidate orbits for several tracking performance levels. As part of determining formation requirements, a formation guidance algorithm called Command Virtual Structure is introduced that can reduce the (Delta)(nu) requirements compared to standard Leader/Follower formation approaches.

  10. Fibril formation from pea protein and subsequent gel formation.

    PubMed

    Munialo, Claire Darizu; Martin, Anneke H; van der Linden, Erik; de Jongh, Harmen H J

    2014-03-19

    The objective of this study was to characterize fibrillar aggregates made using pea proteins, to assemble formed fibrils into protein-based gels, and to study the rheological behavior of these gels. Micrometer-long fibrillar aggregates were observed after pea protein solutions had been heated for 20 h at pH 2.0. Following heating of pea proteins, it was observed that all of the proteins were hydrolyzed into peptides and that 50% of these peptides were assembled into fibrils. Changes on a structural level in pea proteins were studied using circular dichroism, transmission electron microscopy, and particle size analysis. During the fibril assembly process, an increase in aggregate size was observed, which coincided with an increase in thioflavin T binding, indicating the presence of β-sheet aggregates. Fibrils made using pea proteins were more branched and curly. Gel formation of preformed fibrils was induced by slow acidification from pH 7.0 to a final pH of around pH 5.0. The ability of pea protein-based fibrillar gels to fracture during an amplitude sweep was comparable to those of soy protein and whey protein-based fibrillar gels, although gels prepared from fibrils made using pea protein and soy protein were weaker than those of whey protein. The findings show that fibrils can be prepared from pea protein, which can be incorporated into protein-based fibrillar gels.

  11. Magnetic Assisted Colloidal Pattern Formation

    NASA Astrophysics Data System (ADS)

    Yang, Ye

    Pattern formation is a mysterious phenomenon occurring at all scales in nature. The beauty of the resulting structures and myriad of resulting properties occurring in naturally forming patterns have attracted great interest from scientists and engineers. One of the most convenient experimental models for studying pattern formation are colloidal particle suspensions, which can be used both to explore condensed matter phenomena and as a powerful fabrication technique for forming advanced materials. In my thesis, I have focused on the study of colloidal patterns, which can be conveniently tracked in an optical microscope yet can also be thermally equilibrated on experimentally relevant time scales, allowing for ground states and transitions between them to be studied with optical tracking algorithms. In particular, I have focused on systems that spontaneously organize due to particle-surface and particle-particle interactions, paying close attention to systems that can be dynamically adjusted with an externally applied magnetic or acoustic field. In the early stages of my doctoral studies, I developed a magnetic field manipulation technique to quantify the adhesion force between particles and surfaces. This manipulation technique is based on the magnetic dipolar interactions between colloidal particles and their "image dipoles" that appear within planar substrate. Since the particles interact with their own images, this system enables massively parallel surface force measurements (>100 measurements) in a single experiment, and allows statistical properties of particle-surface adhesion energies to be extracted as a function of loading rate. With this approach, I was able to probe sub-picoNewton surface interactions between colloidal particles and several substrates at the lowest force loading rates ever achieved. In the later stages of my doctoral studies, I focused on studying patterns formed from particle-particle interaction, which serve as an experimental model of

  12. Lower Eocene alluvial paleosols (Willwood Formation, Northwest Wyoming, U.S.A.) and their significance for paleoecology, paleoclimatology, and basin analysis

    USGS Publications Warehouse

    Bown, T.M.; Kraus, M.J.

    1981-01-01

    The lower Eocene Willwood Formation of northwest Wyoming is a 700 m thick accumulation of alluvial floodplain and channel mudstones and sandstones, nearly all of which show paleopedogenic modifications. Pedogenesis of Willwood sandstones is indicated by taproot and vertebrate and invertebrate bioturbation, early local cementation by calcium carbonate, and thin illuviation cutans on clastic grains. Pedogenesis in Willwood mudstones is indicated by plant bioturbation, insect and other invertebrate burrow casts and lebensspuren; free iron, aluminum, and manganese mobilization, including hydromorphic gleying; sesquioxide and calcareous glaebule formation in lower parts of the solum; presence of clay-rich and organic carbon-rich zones; and well differentiated epipedons and albic and spodic horizons. Probable A horizons are also locally well developed. Occurrence of variegated paleosol units in thick floodplain mudstone deposits and their association with thin, lenticular, and unconnected fluvial sandstones in the Willwood Formation of the central and southeast Bighorn Basin suggest that these soils formed during times of rapid sediment accumulation. The tabular geometry and lateral persistence of soil units as well as the absence of catenization indicate that Willwood floodplains were broad and essentially featureless. All Willwood paleosols were developed on alluvial parent materials and are complex in that B horizons of younger paleosols were commonly superimposed upon and mask properties of suspected A and B horizons of the next older paleosols. The soils appear to be wet varieties of the Spodosol and Entisol groups (aquods and ferrods, and aquents, respectively), though thick, superposed and less mottled red, purple, and yellow paleosols resemble some ultisols. Most Willwood paleosols resemble warm temperate to subtropical alluvial soils that form today under alternating wet and dry conditions and (or) fluctuating water tables. The up-section decrease in frequency

  13. Galaxy interactions and star formation: Results of a survey of global H-alpha emission in spiral galaxies in 8 clusters

    NASA Technical Reports Server (NTRS)

    Moss, C.

    1990-01-01

    Kennicutt and Kent (1983) have shown that the global H alpha emission from a spiral galaxy is an indicator of the formation rate of massive stars. Moss, Whittle and Irwin (1988) have surveyed two clusters (Abell 347 and 1367) for galaxies with H alpha emission using a high dispersion objective prism technique. The purpose of the survey is to investigate environmental effects on star formation in spiral galaxies, and in particular to ascertain whether star formation is enhanced in cluster spirals. Approximately 20 percent of CGCG galaxies were detected in emission. Two plates of excellent quality were obtained for each of the two clusters, and galaxies were only identified to have emission if this was detected on both plates of a plate pair. In this way, plate flaws and other spurious identifications of emission could be rejected, and weak emission confirmed. The results of this survey have been discussed by Moss (1987). The detected galaxies are of types SO-a and later. The frequency with which galaxies are detected in emission increases towards later morphological type as expected (cf. Kennicutt and Kent 1983). There is no evidence of any dependence of the frequency of detected emission on the absolute magnitude of the galaxy (cf. Moss and Whittle 1990), but there is a strong correlation between a disturbed morphological appearance of the galaxy and the detection of emission. Furthermore it is found that the emission is more centrally concentrated in those galaxies which show a disturbed morphology. It may be noted that the objective prism plate gives a spectrum of a 400 A region around rest wavelength H alpha, but superposed on this is the H alpha emission from the galaxy which, because the light is essentially monochromatic, results in a true two-dimensional image of the H alpha distribution. The visual appearance of the emission on the prism plates was classified according to its diffuseness on a 5 point scale (very diffuse, diffuse, intermediate, compact, and

  14. The Growth of Magma Bodies by Amalgamation of Discrete Sheet Intrusions: Implications for the Formation of Magma Chambers

    NASA Astrophysics Data System (ADS)

    Annen, C.

    2007-12-01

    Until recently, igneous bodies (plutons and magma chambers) were commonly considered to be approximately spherical bodies, rapidly emplaced into the crust. However, field, structural, geophysical, and geochronological studies indicate that many plutons are low aspect-ratio tabular bodies (sills) that are formed by the amalgamation of successive discrete magma pulses. The thermal evolution of an igneous body that grows by accretion of thin magma sheets is fundamentally different from the evolution of a rapidly emplaced magma sphere or of a single thick magma sill. In thin sheet intrusions, the heat loss is through the walls of the sheets and the temperatures within the intrusions do not depend on the volumes injected but on the one-dimension sheets emplacement rate. The first sheets injected in a cold crust rapidly cool down and solidify. The ability of successive intrusions to stay at high temperature and eventually build up a long-lived magma chamber is controlled by the emplacement rate. Heat transfer modeling applied in the context of a volcanic arc shows that average emplacement rates of at least several centimeters per year and an incubation time of tens thousands of years are needed for a persistent magma chamber to form. During the incubation time, the intrusions solidify and when a chamber of high melt fraction magma eventually grows, the volume of eruptible magma only form a small part of the total intruded volume. The emplacement rate of plutons is controversial. Geochronological data suggest that some plutons may be emplaced over millions years. For a pluton that is assembled at a slow rate of a few millimeters per year, millions of years are needed, over which kilometric thicknesses are intruded, before a volume of magma larger than the size of a single intrusion becomes mobile and eruptible. In many cases, volcanic products may come from a deep source without being associated with a long-lived upper crust magma chamber. If volcanism is associated with

  15. Formation of lunar basin rings

    USGS Publications Warehouse

    Hodges, C.A.; Wilhelms, D.E.

    1978-01-01

    The origin of the multiple concentric rings that characterize lunar impact basins, and the probable depth and diameter of the transient crater have been widely debated. As an alternative to prevailing "megaterrace" hypotheses, we propose that the outer scarps or mountain rings that delineate the topographic rims of basins-the Cordilleran at Orientale, the Apennine at Imbrium, and the Altai at Nectaris-define the transient cavities, enlarged relatively little by slumping, and thus are analogous to the rim crests of craters like Copernicus; inner rings are uplifted rims of craters nested within the transient cavity. The magnitude of slumping that occurs on all scarps is insufficient to produce major inner rings from the outer. These conclusions are based largely on the observed gradational sequence in lunar central uplifts:. from simple peaks through somewhat annular clusters of peaks, peak and ring combinations and double ring basins, culminating in multiring structures that may also include peaks. In contrast, belts of slump terraces are not gradational with inner rings. Terrestrial analogs suggest two possible mechanisms for producing rings. In some cases, peaks may expand into rings as material is ejected from their cores, as apparently occurred at Gosses Bluff, Australia. A second process, differential excavation of lithologically diverse layers, has produced nested experimental craters and is, we suspect, instrumental in the formation of terrestrial ringed impact craters. Peak expansion could produce double-ring structures in homogeneous materials, but differential excavation is probably required to produce multiring and peak-in-ring configurations in large lunar impact structures. Our interpretation of the representative lunar multiring basin Orientale is consistent with formation of three rings in three layers detected seismically in part of the Moon-the Cordillera (basin-bounding) ring in the upper crust, the composite Montes Rook ring in the underlying

  16. Eye formation in the absence of retina

    PubMed Central

    Swindell, Eric C.; Liu, Chaomei; Shah, Rina; Smith, April N.; Lang, Richard A.; Jamrich, Milan

    2008-01-01

    Eye development is a complex process that involves the formation of the retina and the lens, collectively called the eyeball, as well as the formation of auxiliary eye structures such as the eyelid, lacrimal gland, cornea and conjunctiva. The developmental requirements for the formation of each individual structure are only partially understood. We have shown previously that the homeobox-containing gene Rx is a key component in eye formation, as retinal structures do not develop and retina-specific gene expression is not observed in Rx-deficient mice. In addition, Rx−/− embryos do not develop any lens structure, despite the fact that Rx is not expressed in the lens. This demonstrates that during normal mammalian development, retina-specific gene expression is necessary for lens formation. In this paper we show that lens formation can be restored in Rx-deficient embryos experimentally, by the elimination of β-catenin expression in the head surface ectoderm. This suggests that β-catenin is involved in lens specification either through Wnt signaling or through its function in cell adhesion. In contrast to lens formation, we demonstrate that the development of auxiliary eye structures does not depend on retina-specific gene expression or retinal morphogenesis. These results point to the existence of two separate developmental processes involved in the formation of the eye and its associated structures. One involved in the formation of the eyeball and the second involved in the formation of the auxiliary eye structures. PMID:18675797

  17. Cloud formation in Titan's Stratosphere

    NASA Astrophysics Data System (ADS)

    Barth, Erika

    2016-06-01

    In addition to the organic haze particles produced photochemically in Titan's upper atmosphere, a number of trace gases are also created. These hydrocarbon and nitrile species include C2H6, C2H2, C4H10, HCN, HC3N, C2H5CN and many more. While both Voyager and Cassini observations have found evidence for ices (e.g. C4N2, HCN) in the atmosphere above Titan's poles, these species are also likely to condense at other latitudes forming optically thin ice layers in the stratosphere. A series of simulations have been conducted using Titan CARMA, a 1-D microphysics and radiative transfer model, to explore cloud particle formation with ˜20 of Titan's trace hydrocarbon and nitrile gases. These species reach their condensation temperatures between 60 and 110 km. Most condense solely as ices, however, C3H8 will condense first near 70 km as a liquid and then freeze as the droplets descend toward the surface. C3H8 and C2H6 join CH4 as a liquid at Titan's surface. Many ices have long condensation timescales resulting in particle radii ˜1 micron or less. Several (including HCN, C3H8, C2H2) will grow 10-50 times larger. Expected condensation altitudes and particle sizes will be presented, as well as the implications for the optical properties of Titan's stratospheric aerosol particles.

  18. Pattern Formation in Excitable Media

    NASA Astrophysics Data System (ADS)

    Reynolds, William Nash

    1992-01-01

    The phenomenon of excitability is observed in a wide variety of physical and biological systems. In this work, spatially extended excitable systems are examined from several different perspectives. First, a pedagogical introduction is used to motivate the derivation of the dynamics of one dimensional excitable pulses. In the second part, coupled map techniques for numerical simulation of excitable media and other interfacial systems are described. Examples are given for both excitable media and crystal growth. The third chapter addresses the phenomenon of spiral formation in excitable media. Exact rotating solutions are found for a class of models of excitable media. The solutions consist of two regions: an outer region, consisting of the spiral proper, which exhibits a singularity at its tip, and the core region, obtained by rescaling space in the vicinity of the tip. The tip singularity is resolved in the core region, leading to a consistent solution in all of space. The stability of both the spiral and the core is investigated, with the result that the spiral is found to be stable, and the core unstable. Finally, the stability of excitable waves of the chemical cAMP traveling over aggregating colonies of the slime mold Dictyostelium discoideum is examined by coupling the excitable dynamics of the cAMP signalling system to a simple model of chemotaxis, with result that cellular motion is found to destabilize the waves, causing the initially uniform field of cells to break up into streams.

  19. Planetesimal Formation: Theory vs. Simulation

    NASA Astrophysics Data System (ADS)

    Youdin, Andrew

    2008-09-01

    Recent numerical simulations by Johansen et al. (2007, Nature) demonstrate that large ( 1000 km-sized) planetesimals can form by the gravitational collapse of many meter-sized boulders. These expensive simulations couple the turbulent magnetohydrodynamic gas to the self-gravitating, N-body evolution of particles. This talk explores how we can use analytic theories to understand these results. The goal is to extrapolate to regions of parameter space which are cosmogonically interesting, but too costly to simulate. Notably, starting with mm-sized chondrules could require unreasonably long simulations approaching a Myr. Towards this end, I present a refined theory for the gravitational collapse of solids subject to gas drag. This model includes a more detailed treatment of stirring by turbulent gas. I will explain why this (still simplistic) model gives more pessimistic results than the simulations. The answer lies in the paradox that turbulence can be both harmful and helpful for the formation of planetesimals, which has been a stumbling block for decades.

  20. Fertilization and early seed formation.

    PubMed

    Dumas, Christian; Rogowsky, Peter

    2008-10-01

    The double fertilization of flowering plants is a complex process, encompassing multiple steps. From its discovery more than a century ago, many useful descriptive approaches have been employed to better unveil specific steps/mechanisms. More recently, the development of an in vitro assay developed in our laboratory, has allowed a better understanding of this phenomenon. However, in vitro methods may show some limitations. The search for complementary strategies, especially with the search of mutants affected in the fertilization step allowed one to elucidate this critical and unique phenomenon in living organisms. Genes involved in pollen tube guidance or pollen discharge in synergids have been identified, as well as genes exhibiting differential expression in sperm, egg and central cells before and after fertilization. A calcium wave proved to correspond to the first cellular event seen after cytoplasmic fusion in the fertilized egg cell or zygote, which develops into a multi-cellular organism with an elaborate body plan. The development of the fertilized central cell into a nourishing tissue (endosperm) starts with the formation of the coenocyte, a multinuclear single cell unique in the plant kingdom, cellularization occurring later on. The balance of the paternal and maternal genomes, which is under the control of the FIS polycomb group complex, was found to be of the utmost importance for the successful development of the seed.