Sample records for tabular ascii format

  1. National Sewage Sludge Survey (NSSS), data element dictionary for the ASCII format databases

    SciTech Connect

    Not Available

    1992-11-16

    A data element dictionary including ASCII database file structures, variable naming conventions, and unique identifier variables is provided for the ASCII formats of the Questionnaire, Data Conventions, and Analytical Databases for the 1988 National Sewage Sludge Use and Disposal Survey (NSSS). Data collected in the questionnaire component of the survey are contained in the Questionnaire Database. Revised questionnaire data, including regulatory analytical use or disposal practices, followup information from the Publicly Owned Treatment Works (POTWs), and imputed values for missing or improbable responses which could not be resolved, are recorded in the Data Conventions Database. Chemical concentrations from sewage sludge samples collected just prior to disposal are recorded in the Analytical Database.

  2. 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

  3. Technical Report: CSVM format for scientific tabular data CSVM specification (CSVM-1): concept and design, guidelines, parsers.

    E-print Network

    Paris-Sud XI, Université de

    for database management systems (cf. NoSQL4 ). Later the work was extended in other scientific fields Separated Values 1 ) is a de facto industry standard to exchange tabular data from spreadsheets or databases

  4. Efficient Tabular LR Parsing

    Microsoft Academic Search

    Mark-Jan Nederhof; Giorgio Satta

    1996-01-01

    We give a new treatment of tabular LR parsing, which is an alternative to Tomita's generalized LR algorithm. The advantage is twofold. Firstly, our treatment is conceptually more attractive because it uses simpler concepts, such as grammar transformations and standard tabulation techniques also know as . Secondly, the static and dynamic complexity of parsing, both in space and time, is

  5. Geochemical properties of the water-snow-ice complexes in the area of Shokalsky glacier, Novaya Zemlya, in relation to tabular ground-ice formation

    Microsoft Academic Search

    M. O. Leibman; S. M. Arkhipov; D. D. Perednya; A. S. Savvichev; B. G. Vanshtein; H. W. Hubberten

    2005-01-01

    Tabular (massive) ground ice in periglacial areas of the Russian Arctic (Barents and Kara Sea coasts) is considered to be a remnant of past glacial epochs and is thus used as proof of the glacial extent. In this paper, we argue that the origin of these tabular ice bodies, which can be used as archives of specific climatic conditions and

  6. The NOAA Tide Predictions application provides predictions in both graphical and tabular formats, with many user selected options, for over 3000 stations broken down by key areas in each state.

    E-print Network

    The NOAA Tide Predictions application provides predictions in both graphical and tabular formats. Station Types: The NOAA Tide Predictions application provides predictions from 2 distinct categories by combining the harmonic constituents into a single tide curve. Subordinate - The high and low height values

  7. A MICROPROCESSOR ASCII CHARACTER BUFFERING SYSTEM

    EPA Science Inventory

    A microprocessor buffering system (MBS) was developed at the Environmental Monitoring and Support Laboratory -Cincinnati (EMSL-CI) to provide an efficient transfer for serial ASCII information between intelligent instrument systema and a Data General NOVA laboratory automation co...

  8. JSparklines: Making tabular proteomics data come alive.

    PubMed

    Barsnes, Harald; Vaudel, Marc; Martens, Lennart

    2015-04-01

    Perhaps the most common way of presenting proteomics data, and indeed life sciences data in general, is by using some form of tabular data. And while tables can be very informative and contain lots of information, the format can be challenging to interpret visually. An elegant and efficient solution is to extend the textual and numerical information with an additional visual layer, referred to as sparklines, making it intuitive to draw inferences about the properties of the underlying data. We here present a free and open source Java library called JSparklines (http://jsparklines.googlecode.com) that allows straightforward addition of a substantial list of customizable sparklines to tabular data representations, and we show examples of how these sparklines greatly simplify the interpretation of the tabular data. PMID:25422159

  9. 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

  10. AHDS Arts and Humanities Data Service ASCII American Standard Code for Information Interchange

    E-print Network

    Carr, Leslie

    for Information Interchange BFI British Film Institute BODC British Oceanographic Data Centre CAD Computer Aided77 APPENDIX 3 Acronyms AHDS Arts and Humanities Data Service ASCII American Standard Code Retargetable Binary Translation RLG Research Libraries Group RTF Rich Text Format SCRAN Scottish Cultural

  11. DAWN: A Novel Strategy for Detecting ASCII Worms in Networks

    E-print Network

    Chen, Shigang

    DAWN: A Novel Strategy for Detecting ASCII Worms in Networks Parbati Kumar Manna Sanjay Ranka a detection technique that would exploit those limitations. We introduce DAWN, a novel ASCII worm detection­based detection methods, DAWN is completely signature-free and therefore capable of detecting zero-day outbreak

  12. 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.

  13. 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

    U.S. Geological Survey

    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).

  14. 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

  15. Using Lexical tools to convert Unicode characters to ASCII.

    PubMed

    Lu, Chris J; Browne, Allen C; Divita, Guy

    2008-01-01

    Unicode is an industry standard allowing computers to consistently represent and manipulate text expressed in most of the worlds writing systems. It is widely used in multilingual NLP (natural language processing) projects. On the other hand, there are some NLP projects still only dealing with ASCII characters. This paper describes methods of utilizing lexical tools to convert Unicode characters (UTF-8) to ASCII (7-bit) characters. PMID:18998787

  16. Comprehensibility Improvement of Tabular Knowledge Bases

    E-print Network

    Riesenhuber, Maximilian

    to be a serious burden for the knowledge engineers who must manage knowledge bases. Purpose of this research and only method to improve the comprehensibility of a knowledge base was to simplify the conceptComprehensibility Improvement of Tabular Knowledge Bases Atsushi Sugiuray Maximilian yC&C Systems

  17. ERDDAP - A Brokering Data Server for Gridded and Tabular Datasets

    NASA Astrophysics Data System (ADS)

    Simons, R. A.; Mendelssohn, R.

    2012-12-01

    ERDDAP is an open-source data server that gives users a simple, consistent way (OPeNDAP requests) to download subsets of scientific datasets in common file formats and make graphs and maps. ERDDAP is a middle man (a broker) between users and various remote data services (and also local databases and files). Using just two internal structures for datasets (multi-dimensional grids and database-like tables) makes the problem manageable and also works well with OPeNDAP's projection constraints (for gridded data) and selection constraints (for tabular/sequence data).;

  18. Fast Mining of Massive Tabular Data via Approximate Distance Computations

    Microsoft Academic Search

    Graham Cormode; Piotr Indyk; Nick Koudas; S. Muthukrishnan

    2002-01-01

    Tabular data abound in many data stores: traditional re- lational databases store tables, and new applications also generate massive tabular datasets. For example, consider the geographic distribution of cell phone traffic at different base stations across the country or the evolution of traffic at Internet routers over time . Detecting similarity patterns in such data sets (e.g., which geographic regions

  19. ASCII Phonetic Symbols for the World's Languages: Worldbet James L. Hieronymus

    E-print Network

    Hosom, John-Paul

    ASCII Phonetic Symbols for the World's Languages: Worldbet James L. Hieronymus AT&T Bell Laboratories, Murray Hill, NJ 07974, USA Abstract A new ASCII encoding of the International Phonetic Alphabet a large number of languages with phonemic and phonetic symbols, these were found to be inadequate

  20. ASCII Phonetic Symbols for the World's Languages: Worldbet James L. Hieronymus

    E-print Network

    Penn, Gerald

    ASCII Phonetic Symbols for the World's Languages: Worldbet James L. Hieronymus AT&T Bell Laboratories, Murray Hill, NJ 07974, USA Abstract A new ASCII encoding of the International Phonetic Alphabet. When an attempt was made to label a large number of languages with phonemic and phonetic symbols

  1. BayesDB : querying the probable implications of tabular data

    E-print Network

    Baxter, Jay

    2014-01-01

    BayesDB, a Bayesian database table, lets users query the probable implications of their tabular data as easily as an SQL database lets them query the data itself. Using the built-in Bayesian Query Language (BQL), users ...

  2. Starbase Data Tables: An ASCII Relational Database for Unix

    NASA Astrophysics Data System (ADS)

    Roll, John

    2011-11-01

    Database management is an increasingly important part of astronomical data analysis. Astronomers need easy and convenient ways of storing, editing, filtering, and retrieving data about data. Commercial databases do not provide good solutions for many of the everyday and informal types of database access astronomers need. The Starbase database system with simple data file formatting rules and command line data operators has been created to answer this need. The system includes a complete set of relational and set operators, fast search/index and sorting operators, and many formatting and I/O operators. Special features are included to enhance the usefulness of the database when manipulating astronomical data. The software runs under UNIX, MSDOS and IRAF.

  3. 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.

  4. The application of short rockbolts in ultradeep tabular stoping

    Microsoft Academic Search

    M. K. C. Roberts?; R. A. Lamos; S. K. Murphy

    2004-01-01

    Most rock related fatalities and injuries in South African gold mines occur in the stope face area. These mines generally do not use rockbolts to support this area. This paper describes short rockbolt applications in the stope face area in a narrow tabular ultradeep Carbon Leader stope. The project began with the geotechnical definition of the generic Carbon Leader Reef

  5. A Distribution-Free Tabular CUSUM Chart for Autocorrelated Data

    E-print Network

    Kim, Seong-Hee

    of an autocorrelated process. The chart's average run length (ARL) is approximated by gener- alizing Siegmund's ARL. The new chart is compared with other distribution-free procedures using stationary test processes with both normal and nonnormal marginals. Key Words: Statistical Process Control; Tabular CUSUM Chart

  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 [Los Alamos National Laboratory

    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. Supporting awareness through collaborative brushing and linking of tabular data.

    PubMed

    Hajizadeh, Amir Hossein; Tory, Melanie; Leung, Rock

    2013-12-01

    Maintaining an awareness of collaborators' actions is critical during collaborative work, including during collaborative visualization activities. Particularly when collaborators are located at a distance, it is important to know what everyone is working on in order to avoid duplication of effort, share relevant results in a timely manner and build upon each other's results. Can a person's brushing actions provide an indication of their queries and interests in a data set? Can these actions be revealed to a collaborator without substantially disrupting their own independent work? We designed a study to answer these questions in the context of distributed collaborative visualization of tabular data. Participants in our study worked independently to answer questions about a tabular data set, while simultaneously viewing brushing actions of a fictitious collaborator, shown directly within a shared workspace. We compared three methods of presenting the collaborator's actions: brushing & linking (i.e. highlighting exactly what the collaborator would see), selection (i.e. showing only a selected item), and persistent selection (i.e. showing only selected items but having them persist for some time). Our results demonstrated that persistent selection enabled some awareness of the collaborator's activities while causing minimal interference with independent work. Other techniques were less effective at providing awareness, and brushing & linking caused substantial interference. These findings suggest promise for the idea of exploiting natural brushing actions to provide awareness in collaborative work. PMID:24051785

  9. 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.

  10. 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.

  11. 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.

  12. The origin and significance of large, tabular dunite bodies in the Trinity peridotite, northern California

    Microsoft Academic Search

    James E. Quick

    1982-01-01

    Kilometer-sized, tabular dunite bodies are contained within harzburgite, lherzolite and plagioclase lherzolite host rocks in the Trinity peridotite, northern California. An igneous origin for the dunite by crystal fractionation of olivine from a melt is suggested by their tabular shapes, clots of poikilitic clinopyroxene grains, chromite pods, and by analogy to dunite bodies in the Samail and Vourinos ophiolites (Hopson

  13. Consistent thermodynamic derivative estimates for tabular equations of state.

    NASA Astrophysics Data System (ADS)

    Dilts, Gary

    2005-07-01

    A valid fluid equation of state must satisfy the thermodynamic differential conditions of consistency (derivation from a free energy) and stability (positive sound speed squared). Typical software interfaces to tabular equations of state based on polynomial or rational interpolants compute derivatives of pressure and energy and may enforce the stability conditions, but do not enforce the consistency condition and its derivatives, which is important for the computation of dimensionless quantities associated with more sensitive artificial viscosities and Riemann solvers that accurately model shock structure in regions near phase transitions. We describe a new type of table interface derived from a constrained local least squares regression technique. Application to several SESAME tables shows the consistency condition can be satisfied to round-off with third-order accuracy. An improvement of 14 orders of magnitude over conventional derivatives is demonstrated, although the new method is two orders of magnitude slower, due to solving an 11-dimensional nonlinear system. The new approach can be used to construct consistent and stable tables of derivatives, however.

  14. Consistent thermodynamic derivative estimates for tabular equations of state

    NASA Astrophysics Data System (ADS)

    Dilts, Gary A.

    2006-06-01

    A valid fluid equation of state (EOS) must satisfy the thermodynamic conditions of consistency (derivation from a free energy) and stability (positive sound speed squared). Numerical simulations of compressible fluid flow for realistic materials require a tabular EOS, but typical software interfaces to such tables based on polynomial or rational interpolants may enforce the stability conditions, but do not enforce the consistency condition and its derivatives. The consistency condition is important for the computation of various dimensionless parameters of an EOS that may involve derivatives of up to second order which are important for the development of more sensitive artificial viscosities and Riemann solvers that accurately model shock structure in regions near phase transitions. We describe a table interface based on the tuned regression method, which is derived from a constrained local least-squares regression technique. It is applied to several SESAME EOS showing how the consistency and stability conditions can be satisfied to round-off while computing first and second derivatives with demonstrated second-order convergence. An improvement of 14 orders of magnitude over conventional derivatives is demonstrated, although the method is apparently two orders of magnitude slower, due to the fact that every evaluation requires solving an 11-dimensional nonlinear system. Application is made to the computation of the fundamental derivative.

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. Combining tabular, rule-based, and procedural knowledge in computer-based guidelines for childhood immunization.

    PubMed

    Miller, P L; Frawley, S J; Sayward, F G; Yasnoff, W A; Duncan, L; Fleming, D W

    1997-06-01

    IMM/Serve is a computer program which implements the clinical guidelines for childhood immunization. IMM/Serve accepts as input a child's immunization history. It then indicates which vaccinations are due and which vaccinations should be scheduled next. The clinical guidelines for immunization are quite complex and are modified quite frequently. As a result, it is important that IMM/Serve's knowledge be represented in a format that facilitates the maintenance of that knowledge as the field evolves over time. To achieve this goal, IMM/Serve uses four representations for different parts of its knowledge base: (1) Immunization forecasting parameters that specify the minimum ages and wait-intervals for each dose are stored in tabular form. (2) The clinical logic that determines which set of forecasting parameters applies for a particular patient in each vaccine series is represented using if-then rules. (3) The temporal logic that combines dates, ages, and intervals to calculate recommended dates, is expressed procedurally. (4) The screening logic that checks each previous dose for validity is performed using a decision table that combines minimum ages and wait intervals with a small amount of clinical logic. A knowledge maintenance tool, IMM/Def, has been developed to help maintain the rule-based logic. The paper describes the design of IMM/Serve and the rationale and role of the different forms of knowledge used. PMID:9281329

  20. 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).

  1. Multiple Foci Drill-Down through Tuple and Attribute Polyarchies in Tabular Data

    E-print Network

    Multiple Foci Drill-Down through Tuple and Attribute Polyarchies in Tabular Data Nathan Conklin user guided drill-down of polyarchical metadata. This metadata describes multiple hierarchical of visualizations at each level of the hierarchy. Breakdown Visualization allows users to drill-down a single

  2. 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.

  3. Formation of tabular single-domain magnetite induced by Geobacter metallireducens GS-15

    E-print Network

    at high temperatures (3). Magnetite crystals formed by magnetotactic bacteria (mag- netosomes) also have morphological characteristics of magnetite formed intra- cellularly by magnetic bacteria (magnetosome of magnetite produced extracellularly by a variety of bacteria including Geobacter metallireducens GS-15

  4. The origin and significance of large, tabular dunite bodies in the Trinity peridotite, northern California

    NASA Astrophysics Data System (ADS)

    Quick, James E.

    1982-03-01

    Kilometer-sized, tabular dunite bodies are contained within harzburgite, lherzolite and plagioclase lherzolite host rocks in the Trinity peridotite, northern California. An igneous origin for the dunite by crystal fractionation of olivine from a melt is suggested by their tabular shapes, clots of poikilitic clinopyroxene grains, chromite pods, and by analogy to dunite bodies in the Samail and Vourinos ophiolites (Hopson et al. 1981; Harkins et al. 1980; Moores 1969). However, structures and systematic variations in mineralogy and mineral chemistry suggest that at least the marginal few meters of the bodies are residues produced by extraction of a basaltic component from a plagioclase lherzolite protolith. A model is suggested in which a picritic melt ascended through the upper mantle in vertically oriented channels. Part of the dunite in the tabular bodies was produced by fractional crystallization of olivine from the melt. Additional dunite at the margins of the bodies was formed by extraction of a basaltic component from plagioclase lherzolite wall-rocks during partial assimilation by the picritic melt. The latter process is similar to the “wall-rock reaction” discussed by Green and Ringwood (1967) and is essentially zone refining of the the mantle wall rocks by the migrating melt. It is significant because it suggests a mechanism in addition to fractional crystallization for enrichment of incompatible elements in basalts.

  5. 45 CFR Appendix C to Part 1355 - Electronic Data Transmission Format

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...agency: (1) Records must be written using ASCII standard character format. (2) All elements must be comprised of integer (numeric) value(s). Element character length specifications refer to the maximum number of numeric values permitted...

  6. 45 CFR Appendix C to Part 1355 - Electronic Data Transmission Format

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...agency: (1) Records must be written using ASCII standard character format. (2) All elements must be comprised of integer (numeric) value(s). Element character length specifications refer to the maximum number of numeric values permitted...

  7. 45 CFR Appendix C to Part 1355 - Electronic Data Transmission Format

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...agency: (1) Records must be written using ASCII standard character format. (2) All elements must be comprised of integer (numeric) value(s). Element character length specifications refer to the maximum number of numeric values permitted...

  8. 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).

  9. 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).

  10. Tabular water properties interface for Hydra-TH : CASL THM.CFD.P6.03 milestone report.

    SciTech Connect

    Carpenter, John H.; Belcourt, 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

  11. The table lens: merging graphical and symbolic representations in an interactive focus+context visualization for tabular information

    Microsoft Academic Search

    Ramana Rao; Stuart K. Card

    1994-01-01

    We present a new visualization, called the Table Lens, for visualizing and making sense of large tables. The visual- ization uses a focus+context (fisheye) technique that works effectively on tabular information because it allows display of crucial label information and multiple distal focal areas. In addition, a graphical mapping scheme for depicting table contents has been developed for the most

  12. Tracking large tabular icebergs using the SeaWinds Ku-band microwave scatterometer

    NASA Astrophysics Data System (ADS)

    Stuart, K. M.; Long, D. G.

    2011-06-01

    Knowledge of iceberg locations is important for safety reasons as well as for understanding many geophysical and biological processes. Originally designed to measure wind speed and direction over the ocean, SeaWinds is a microwave scatterometer that operates at 13.4 GHz (Ku-band) on the QuikSCAT satellite. Radar measurements from SeaWinds are collected and processed on a daily basis using resolution-enhancement techniques to produce daily radar images. Because icebergs scatter microwave energy more than sea ice and sea water, icebergs are detected as high-backscatter targets surrounded by lower-backscatter regions in daily SeaWinds images. As a result, iceberg positions are determined in real-time and a time-series of iceberg positions is maintained in an Antarctic iceberg database by Brigham Young University's Microwave Earth Remote Sensing (MERS) laboratory. Since SeaWinds operates independent of both solar illumination and cloud cover and has a large daily spatial coverage, this paper demonstrates that SeaWinds is an excellent platform to detect and track large tabular icebergs. These icebergs are generally larger than 5 km and are typically characterized as a rough ice plateau above the surrounding sea water or sea ice. The number of icebergs tracked in the MERS Antarctic iceberg database is found to be generally greater than the number of icebergs tracked by the National Ice Center. The movement patterns of all icebergs detected by SeaWinds are also analyzed and 90% of icebergs are found to travel a counter-clockwise path around Antarctica and accumulate in the Weddell and Scotia Seas. Iceberg detection and tracking is demonstrated via multiple case studies that highlight icebergs C-19a and A-22a using the MERS database and through real-time operational support of the 2005, 2008, and 2009 NSF Antarctic cruises. Iceberg positions are validated by using collocated high-resolution satellite imagery and by navigating the NSF ships to physically intercept several large tabular icebergs in the Weddell and Scotia Seas.

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

    SciTech Connect

    Liu, Xiang W., E-mail: lxwluck@gmail.co [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 980-8577 Suita (Japan); Devaraju, M.K.; Yin, Shu; Sato, Tsugio [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 980-8577 Suita (Japan)

    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.

  14. 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.

  15. Dynamical Domain Tabular Collisional Radiative Equilibrium Radiation Transport Model for Argon Gas-Puff Z-Pinch Plasmas

    Microsoft Academic Search

    Y. K. Chong; J. W. Thornhill; J. P. Apruzese; J. Davis; H. D. Minor

    2005-01-01

    Summary form only given. The proper treatment of the radiation transport in the multidimensional MHD simulations of large diameter argon gas-puff Z-pinch loads is essential in understanding and predicting accurately the dynamic evolution and the radiative emission characteristics of the plasmas. The tabular collisional radiative equilibrium (TCRE) radiation transport model represents a novel approach to the realistic self-consistent treatment of

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

    Microsoft Academic Search

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

    2010-01-01

    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

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

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...or columnar format exceed 132 positions wide. (b) Paragraph (a) of this section does not apply to HTML documents, Interactive Data Files (§ 232.11) or XBRL-Related Documents (§ 232.11). [58 FR 14670, Mar. 18, 1993, as amended...

  18. 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 activity of 3000 Bq/m3, unrelated to spring altitude. Similar radon activity is also found in a deep well in the Lias-confined aquifer of the Sais Basin and is hence considered to be the steady state activity in k-aquifer. Other springs situated at lower altitude yield more mineralised water (EC = 1200 uS/cm), richer in Na, K, Cl and Rn (15000 Bq/m3). These waters partially interacted with a non-karstic aquifer, most probably the deeper underlying Paleozoic schists (p-aquifer), as suggested by hydro chemical similarity with a water sample collected from a well in these shists. Since such water springs-out of Liassic carbonates, the measured Rn activity probably differs from the equilibrium activity achieved in the underlying p-aquifer, depending on the transit time from p-aquifer and the radon half-life (3.8 days). Furthermore, three other springs have hydrochemical characteristics intermediate between p- and k-aquifers, suggesting that a binary mixing of these waters occurred, either in the k- or in the p- aquifer. In principle, if the groundwater mixing occurred in k-aquifer, unsupported Rn activity would be lower than the activity expected from the binary mixing because of the time elapsed since the mixing occurred. The data show on the contrary that the mixed water has Rn activity higher than the expected activity calculated from the mixing. This suggests that groundwater mixing occurred in the p-aquifer. The excess of radon relatively to the expected activity calculated after the mixing, is interpreted to result from Rn radioactive ingrowth during the residence time in the p-aquifer, followed by radon decay occurred during uplift from p-aquifer to the spring in the Liassic carbonates. With this simple model, the measured Rn excess constraints the total time elapsed since the beginning of interaction with the p-aquifer on a time scale of 2 weeks. Remote sensed imaging of the area evidences that these "mixed" springs lies on important tectonic alignments, which suggest that fractures system could play a role in the fast upwelling of groundwater.

  19. Tabular Summary of the Third Follow-Up Questionnaire Data. Volume 1 [and] Volume 2 [and] Volume 3 [and] Volume 4. Sponsored Report Series NCES 79-228.

    ERIC Educational Resources Information Center

    Peng, Samuel S.; And Others

    Tabular summaries of the 153 numerical responses to the Second Followup Questionnaire items of the National Longitudinal Study of the High School Class of 1972 are presented--20,872 individuals responded. These items summarize participants' educational experiences and occupational attainments from October 1973 to October 1974; continuing or…

  20. supraHex: An R/Bioconductor package for tabular omics data analysis using a supra-hexagonal map?

    PubMed Central

    Fang, Hai; Gough, Julian

    2014-01-01

    Biologists are increasingly confronted with the challenge of quickly understanding genome-wide biological data, which usually involve a large number of genomic coordinates (e.g. genes) but a much smaller number of samples. To meet the need for data of this shape, we present an open-source package called ‘supraHex’ for training, analysing and visualising omics data. This package devises a supra-hexagonal map to self-organise the input data, offers scalable functionalities for post-analysing the map, and more importantly, allows for overlaying additional data for multilayer omics data comparisons. Via applying to DNA replication timing data of mouse embryogenesis, we demonstrate that supraHex is capable of simultaneously carrying out gene clustering and sample correlation, providing intuitive visualisation at each step of the analysis. By overlaying CpG and expression data onto the trained replication-timing map, we also show that supraHex is able to intuitively capture an inherent relationship between late replication, low CpG density promoters and low expression levels. As part of the Bioconductor project, supraHex makes accessible to a wide community in a simple way, what would otherwise be a complex framework for the ultrafast understanding of any tabular omics data, both scientifically and artistically. This package can run on Windows, Mac and Linux, and is freely available together with many tutorials on featuring real examples at http://supfam.org/supraHex. PMID:24309102

  1. 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.

  2. Graphical and tabular summaries of decay characteristics for once-through PWR, LMFBR, and FFTF fuel cycle materials. [Spent fuel, high-level waste fuel can scrap

    SciTech Connect

    Croff, A.G.; Liberman, M.S.; Morrison, G.W.

    1982-01-01

    Based on the results of ORIGEN2 and a newly developed code called ORMANG, graphical and summary tabular characteristics of spent fuel, high-level waste, and fuel assembly structural material (cladding) waste are presented for a generic pressurized-water reactor (PWR), a liquid-metal fast breeder reactor (LMFBR), and the Fast Flux Test Facility (FFTF). The characteristics include radioactivity, thermal power, and toxicity (water dilution volume). Given are graphs and summary tables containing characteristic totals and the principal nuclide contributors as well as graphs comparing the three reactors for a single material and the three materials for a single reactor.

  3. 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.

  4. 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.

  5. Tabular Summary of the Second Follow-Up Questionnaire Data 2 1/2 Years After High School. Volume 1 [and] Volume 2. Sponsored Reports Series. NCES 77-263 Reprint. Reprinted February 1979.

    ERIC Educational Resources Information Center

    Peng, Samuel S.; Holt, Mary M.

    Tabular summaries of the 158 numerical responses to the Third Followup Questionnaire items of the National Longitudinal Study of the High School Class of 1972 are presented--20,092 individuals responded. These items summarize participants' educational experience and occupational attainments from October 1974 to October 1976; continuing or revised…

  6. Binary/BCD-to-ASCII data converter

    NASA Technical Reports Server (NTRS)

    Miller, A. J.

    1977-01-01

    Converter inputs multiple precision binary words, converts data to multiple precision binary-coded decimal, and routes data back to computer. Converter base can be readily changed without need for new gate structure for each base changeover.

  7. Hierarchical data format (HDF5) for Modflow, Modpath and ZoneBudget

    NASA Astrophysics Data System (ADS)

    Cosemans, A.; Batelaan, O.; Louwyck, A.; Lermytte, J.

    2012-04-01

    More and more spatially detailed time dependent groundwater models are used and hence input files for models like Modflow (USGS) are becoming larger and larger. These input files are in ASCII format and contain datasets with values for each cell, changing often for each stress period. To diminish the problem of huge ASCII files, the datasets of the input files can be stored in an HDF5 file (Hierarchical data format). HDF5 is a data model, library and file format designed by HDFgroup for storing and managing data, flexible and efficient input and output and high volume and complex data. The file has a binary format and can be compressed with different kinds of compression methods. An HDF5 file consists among others of groups and datasets, referencing a dataset in the HDF5 file is similar to referencing a file in a folder of a file system. The contents of an HDF5 file can be viewed with HDFview, a Java-based viewer. HDF5 files can be constructed manually with the help of HDFview, or with the help of programming languages like C, C++, Matlab, Fortran or Python. The goal of this contribution is to show how HDF can improve data management of Modflow. A similar HDF5 link to Modflow has been implemented in the interface Groundwater Modeling System. Modflow has been extended to be able to read datasets from the ASCII input files which contain a reference to an HDF5 file for every real 1 or 2-dimensional dataset, every 2-dimensional integer dataset and the stress lists described in the Modflow user manual as U1DREL, U2DREL, U2DINT and ULSTRD. Two other programs from USGS, Modpath and Zonebudget, are also using partly the same input files as Modflow, and have been extended to be able to read the requested datasets from the HDF5 file. The total Modflow input file size, i.e. converted ASCII files and HDF5 file, will be decimated compared to the original size. Partly this is due to 'zlib' compression, 'zlib' is a free lossless data compression library. Due to faster reading of the HDF5 data compared to the original ASCII data model the Modflow, Modpath and ZoneBudget run time decreases.

  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 alterations. In the case of Precambrian unconformity-related deposits, free thermal convection in the thick sandstones overlying the basement rocks carried uranium to concentrations of organic matter in the basement rocks.

  9. Ichnology of Lower Jurassic beach deposits in the Shemshak Formation at Shahmirzad, southeastern Alborz Mountains, Iran

    Microsoft Academic Search

    Franz T. Fürsich; Markus Wilmsen; Kazem Seyed-Emami

    2006-01-01

    A 19 m thick package of well-sorted lowermost Jurassic (Hettangian-Lower Sinemurian?) sandstones within the Shemshak Formation\\u000a of the southeastern Alborz Mountains displays features characteristic of foreshore to upper shoreface environments such as\\u000a tabular bedding, low-angle lamination, trough cross-stratification, parting lineation, and oscillation ripples. In contrast\\u000a to most other beach successions recorded in the literature the sandstones contain a trace fossil assemblage

  10. Deep seismic reflection studies in the Pacific Northwest US, CD-ROM: SEG-Y format

    SciTech Connect

    Zihlman, F.N.; Taylor, D.J.; Stanley, W.D.

    1993-04-01

    This CD-ROM contains the final stack and migrated stack seismic data, in SEG-Y format, from 7 seismic lines collected in western Washington state. Also included are ASCII text files of shot point and CDP locations in latitude/longitude decimal degrees for each line, velocity functions by CDP for both the final stack and migrated data for each line, and field recording and processing parameters for each line. The SEG-Y seismic data files may be graphically displayed on DOS or Macintosh systems using the software included on disc: PLOTSEGY for DOS platforms, or TracePlot for Macintosh platforms. Documentation is provided for all data and software included on this disc in both ASCII text and PostScript format. This CD-ROM was produced in accordance with both the ISO 9660 and Macintosh HFS standards. While the data and text files are accessible by any system recognizing one of those standards, the software is intended for use on either a DOS-based or Macintosh system, as appropriate.

  11. 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; Carl-Ludwig Siegel, Edward

    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)

  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. 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.

  14. 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…

  15. 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.

  16. Documentation for ASCII Text Data Files - SEER Datasets

    Cancer.gov

    SEER is an authoritative source of information on cancer incidence and survival in the United States. SEER currently collects and publishes cancer incidence and survival data from population-based cancer registries covering approximately 28 percent of the U.S. population.

  17. 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.

  18. 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.

  19. Sequence stratigraphic-based reservoir architecture in late Jurrassic outer-ramp carbonates, Hanifa Formation, Saudi Arabia

    SciTech Connect

    Markello, J.R.; Stockton, M.L. (Mobile E P Technical Center, Dallas, TX (United States)); McGuire, M.; Al'Shammery, M.J.; Al'Amoudi M.O. (Saudi Aramco, Dhahran (Saudi Arabia))

    1996-01-01

    The Hanifa Formation (135-160m tk; Kimmeridgian age), in our study area, comprises one 3rd-order, coarsening-upward, type 2 stratigraphic sequence. Sediments formed in outer ramp, ramp-margin and basinal environments defining a transition between the Rimthan Arch carbonate platform and adjacent Arabian intrashelf basin. Quantification of Hanifa reservoir architecture for simulation involved development of field-scale geologic models based on sequence stratigraphic principles. No seismic and biostratigraphic data were available. Sequence interpretations were based on regional facies and parasequence analysis from 32 cores and 142 gamma-ray/porosity logs. In the study area, the Hanifa Formation has basinward-thinning tabular geometry, and contains (1) a lower member of organic-rich muddy carbonates and (2) an upper reservoir member of thick, medium to coarse-grained skeletal packstones, skeletal peloidal grainstones, skeletal intraclast conglomerates, and stromatoporoid boundstones. The Hanifa reservoir consists of, from oldest to youngest: (1) a highstand systems tract: aggrading and prograding, sigmoidal-shaped parasequences and parasequence sets of grainstrines, conglomerates and boundstones, capped by a subaqueous, type 2 sequence boundary; (2) a shelf margin wedge: prograding to aggrading, sigmoidal to tabular-shaped parasequences and parasequence sets of skeletal packstones, grainstones and local boundstones showing maximum basinward progradation; and (3) a transgressive systems tract: backstepping tabular-shaped parasequences of grainstones capped by a drowning surface. All facies are interpreted to have formed in subtidal settings of water depths from 5 to 150m. No evidence was found for shoal-water bank, lagoonal or peritidal deposition or for subaerial exposure in any facies.

  20. Sequence stratigraphic-based reservoir architecture in late Jurrassic outer-ramp carbonates, Hanifa Formation, Saudi Arabia

    SciTech Connect

    Markello, J.R.; Stockton, M.L. [Mobile E & P Technical Center, Dallas, TX (United States); McGuire, M.; Al`Shammery, M.J.; Al`Amoudi M.O. [Saudi Aramco, Dhahran (Saudi Arabia)

    1996-12-31

    The Hanifa Formation (135-160m tk; Kimmeridgian age), in our study area, comprises one 3rd-order, coarsening-upward, type 2 stratigraphic sequence. Sediments formed in outer ramp, ramp-margin and basinal environments defining a transition between the Rimthan Arch carbonate platform and adjacent Arabian intrashelf basin. Quantification of Hanifa reservoir architecture for simulation involved development of field-scale geologic models based on sequence stratigraphic principles. No seismic and biostratigraphic data were available. Sequence interpretations were based on regional facies and parasequence analysis from 32 cores and 142 gamma-ray/porosity logs. In the study area, the Hanifa Formation has basinward-thinning tabular geometry, and contains (1) a lower member of organic-rich muddy carbonates and (2) an upper reservoir member of thick, medium to coarse-grained skeletal packstones, skeletal peloidal grainstones, skeletal intraclast conglomerates, and stromatoporoid boundstones. The Hanifa reservoir consists of, from oldest to youngest: (1) a highstand systems tract: aggrading and prograding, sigmoidal-shaped parasequences and parasequence sets of grainstrines, conglomerates and boundstones, capped by a subaqueous, type 2 sequence boundary; (2) a shelf margin wedge: prograding to aggrading, sigmoidal to tabular-shaped parasequences and parasequence sets of skeletal packstones, grainstones and local boundstones showing maximum basinward progradation; and (3) a transgressive systems tract: backstepping tabular-shaped parasequences of grainstones capped by a drowning surface. All facies are interpreted to have formed in subtidal settings of water depths from 5 to 150m. No evidence was found for shoal-water bank, lagoonal or peritidal deposition or for subaerial exposure in any facies.

  1. Galaxy Formation

    E-print Network

    Eric Gawiser

    2005-12-15

    I summarize current knowledge of galaxy formation with emphasis on the initial conditions provided by the Lambda CDM cosmology, integral constraints from cosmological quantities, and the demographics of high-redshift protogalaxies. Tables are provided summarizing the number density, star formation rate and stellar mass per object, cosmic star formation rate and stellar mass densities, clustering length and typical dark matter halo masses for Lyman break galaxies, Lyman alpha emitting galaxies, Distant red galaxies, Sub-millimeter galaxies, and Damped Lyman alpha absorption systems. I also discuss five key unsolved problems in galaxy formation and prognosticate advances that the near future will bring.

  2. Soil Formation

    NSDL National Science Digital Library

    Humans use soil for their daily needs but do not sufficiently take account of its slow formation and fast loss. Discover the amazing geology of soil formation and the basic rock and soil types.Although soil seems the end product from weathering rocks, it is merely a stage in the gigantic cycle of mineral recycling by the movement of tectonic plates.

  3. Regolith Formation

    NSDL National Science Digital Library

    NASA

    1997-01-01

    In this three-part activity, learners use food to determine the effects of wind, sandblasting and water on regolith (dust) formation and deposition on Earth. Then, learners simulate regolith formation on the Moon by meteorite bombardment, an activity best completed outdoors.

  4. Plasmapause formation

    NASA Astrophysics Data System (ADS)

    Lemaire, J.

    The theory of plasmapause formation is examined. Particular attention is given to the role of magnetospheric fields in the inner magnetosphere, the noon-midnight and dawn-dusk asymmetries, plasma density distribution in the plasmasphere, plasmapause positions in the nightside sector and the daytime LT sector, the LT distribution of detached plasma elements, the growth rate of interchange instability, the formation of new density knees at each new enhancement in magnetospheric convection, and diagmagnetic and finite-temperature effects. The ideal MHD theory for the formation of the plasmapause is considered.

  5. CURSA: Catalog and Table Manipulation Applications

    NASA Astrophysics Data System (ADS)

    Davenhall, A. C.

    2014-05-01

    The CURSA package manipulates astronomical catalogs and similar tabular datasets. It provides facilities for browsing or examining catalogs; selecting subsets from a catalog; sorting and copying catalogs; pairing two catalogs; converting catalog coordinates between some celestial coordinate systems; and plotting finding charts and photometric calibration. It can also extract subsets from a catalog in a format suitable for plotting using other Starlink packages such as PONGO. CURSA can access catalogs held in the popular FITS table format, the Tab-Separated Table (TST) format or the Small Text List (STL) format. Catalogs in the STL and TST formats are simple ASCII text files. CURSA also includes some facilities for accessing remote on-line catalogs via the Internet. It is part of the Starlink software collection (ascl:1110.012).

  6. Galaxy formation

    NASA Technical Reports Server (NTRS)

    Silk, J.

    1984-01-01

    Implications of the isotropy of the cosmic microwave background on large and small angular scales for galaxy formation are reviewed. In primeval adiabatic fluctuations, a universe dominated by cold, weakly interacting nonbaryonic matter, e.g., the massive photino is postulated. A possible signature of photino annihilation in our galactic halo involves production of cosmic ray antiprotons. If the density is near its closure value, it is necessary to invoke a biasing mechanism for suppressing galaxy formation throughout most of the universe in order to reconcile the dark matter density with the lower astronomical determinations of the mean cosmological density. A mechanism utilizing the onset of primordial massive star formation to strip gaseous protogalaxies is described. Only the densest, early collapsing systems form luminous galaxies.

  7. Planet Formation

    NASA Astrophysics Data System (ADS)

    Chambers, J. E.

    The origin of the Sun's planetary system is a long-standing problem but one whose solution may be in sight. Recent progress has been rapid and much has changed since the first edition of this book. This article will describe a reasonably coherent story for the formation of the planets, based on what people know today, with the obvious caveat that future discoveries are bound to change some of the details. This article outlines the various aspects of planet formation according to the current paradigm, with a particular emphasis on the origin of the Sun's planetary system.

  8. 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

  9. ANTIBODY FORMATION

    PubMed Central

    Uhr, Jonathan W.; Baumann, Joyce B.

    1961-01-01

    Diphtheria toxoid-antitoxin precipitates formed in antitoxin excess can prepare guinea pigs, rats, and rabbits for a secondary type of antitoxin response. Priming may occur without the development of detectable serum antibody. In rats, toxoid-antitoxin precipitates are more efficient than "free" toxoid in priming, whereas in guinea pigs, the magnitude of the anamnestic response varies with the precipitate employed. The possibility that priming is due to "free" antigen released from the specific precipitate rather than the precipitate itself is discussed. The anamnestic antitoxin response can be inhibited by passive antitoxin, but less efficiently than primary antitoxin formation. Partial suppression of the secondary antitoxin response was accomplished by injection of excess horse antitoxin as long as 4 days after reimmunization with toxoid. The importance of these findings for the understanding of passive-active immunization in the human is discussed. PMID:13779028

  10. 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

  11. Astropy: A community Python package for astronomy

    NASA Astrophysics Data System (ADS)

    Astropy Collaboration; Robitaille, Thomas P.; Tollerud, Erik J.; Greenfield, Perry; Droettboom, Michael; Bray, Erik; Aldcroft, Tom; Davis, Matt; Ginsburg, Adam; Price-Whelan, Adrian M.; Kerzendorf, Wolfgang E.; Conley, Alexander; Crighton, Neil; Barbary, Kyle; Muna, Demitri; Ferguson, Henry; Grollier, Frédéric; Parikh, Madhura M.; Nair, Prasanth H.; Unther, Hans M.; Deil, Christoph; Woillez, Julien; Conseil, Simon; Kramer, Roban; Turner, James E. H.; Singer, Leo; Fox, Ryan; Weaver, Benjamin A.; Zabalza, Victor; Edwards, Zachary I.; Azalee Bostroem, K.; Burke, D. J.; Casey, Andrew R.; Crawford, Steven M.; Dencheva, Nadia; Ely, Justin; Jenness, Tim; Labrie, Kathleen; Lim, Pey Lian; Pierfederici, Francesco; Pontzen, Andrew; Ptak, Andy; Refsdal, Brian; Servillat, Mathieu; Streicher, Ole

    2013-10-01

    We present the first public version (v0.2) of the open-source and community-developed Python package, Astropy. This package provides core astronomy-related functionality to the community, including support for domain-specific file formats such as flexible image transport system (FITS) files, Virtual Observatory (VO) tables, and common ASCII table formats, unit and physical quantity conversions, physical constants specific to astronomy, celestial coordinate and time transformations, world coordinate system (WCS) support, generalized containers for representing gridded as well as tabular data, and a framework for cosmological transformations and conversions. Significant functionality is under activedevelopment, such as a model fitting framework, VO client and server tools, and aperture and point spread function (PSF) photometry tools. The core development team is actively making additions and enhancements to the current code base, and we encourage anyone interested to participate in the development of future Astropy versions.

  12. 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.

  13. 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.

  14. 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

    2015-02-01

    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 (?2H ˜-15‰, ?18O ˜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.

  15. Treatment of sandstone formations

    Microsoft Academic Search

    J. A. Knox; R. M. Lasater

    1974-01-01

    A method of treating a subterranean sandstone formation with an aqueous acid solution containing hydrofluoric acid is described. The reaction rate of the acid with the formation is retarded and substantial penetration of the formation with active acid results. When the hydrofluoric acid solution contacts the sandstone formation, siliceous minerals and clay in the formation are dissolved, thereby increasing the

  16. The Format War.

    ERIC Educational Resources Information Center

    Kreamer, Jean

    1992-01-01

    Discussion of format changes in libraries focuses on managing change and phasing out older formats. Standardization is addressed, and five considerations regarding format shifts are examined: aesthetics, audience, compatibility, costs, and copyright. (MES)

  17. Design of tabular excavations in foliated rock: an integrated numerical

    E-print Network

    the intact strength of the orebody and host rock, and by the pillars that separate the open stope from previously developed openings. In addition, cable bolting techniques and the use of backfill provides extra

  18. Calving of large tabular icebergs from ice shelf rift systems

    Microsoft Academic Search

    Ian Joughin; Douglas R. MacAyeal

    2005-01-01

    We used Interferometric Synthetic Aperture Radar to study the detachment process that allowed two large icebergs to calve from the Ross Ice Shelf, Antarctica. Time series of rift geometries indicate that rift widths increased steadily, whereas rift lengths increased episodically through several discrete rift-tip propagation events. We also conducted modeling experiments constrained by the observed rift geometry. Both the observations

  19. A heuristic block coordinate descent approach for controlled tabular ...

    E-print Network

    2010-11-05

    a census), which results in sets of tables, usually with a large number of cells. NSAs are obliged by ...... English translation of the original paper ... Language for Optimal CTA, Lecture Notes in Computer Science, 5262, 1–12. [8] Chinneck, J.W.

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

    E-print Network

    Paris-Sud XI, Université de

    NORWAY POLAND PORTUGAL RUSSIA SPAIN SWEDEN UNITEDKINGDOM HOUSEHOLD INCOME WOMEN'S SUFFRAGE DATE AGAINST NOT AS A NEIGHBOUR: HOMOSEXUALS ATTEND CHURCH AT LEAST ONCE A WEEK WOMEN'S SUFFRAGE DATE CZECHREPUBLIC FINLANDPolPorRusSpaSweUni Household in Women's suf Against coha Belief in God Confidence Confidence Confidence Confidence Confidence

  1. Capital Punishment 1997

    NSDL National Science Digital Library

    1999-01-01

    Recently released by the US Department of Justice's Bureau of Justice Statistics, this report presents capital punishment data for 1997 as well as preliminary data on executions in 1998. The report finds that in 1997, 3,335 men and women were on death row in 34 states, and during the year, seventeen states executed 74 prisoners -- all male -- with half of the executions occurring in Texas. Tabular data in the report display prisoners' sex, race, education, marital status, age, and method of execution, and the time between the imposition of the death sentence and execution. The report also includes historical tables that provide data on the 4,291 prisoners executed in the US between 1930 and 1997. The report is available in .pdf and ASCII format. Spreadsheets may be downloaded as a .zip file.

  2. 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).

  3. Star Formation Processes versus Planet Formation Processes

    E-print Network

    Shiv S. Kumar

    2002-08-20

    The processes of star formation are fundamentally different from those of planet formation. Since the mass of a very-low-mass object alone doesn't allow us to uniquely determine its basic nature, we have to look at its other characteristics, such as its motion, its age, its atmospheric composition, its internal structure and composition, etc., in order to ascertain its formation mechanism.

  4. 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.

  5. Water Formatics Engineered formation of nanobubbles networks

    E-print Network

    Jacob, Eshel Ben

    Water Formatics Engineered formation of nanobubbles networks in water and aqueous solutions We present the idea that the anomalous effects of rf-treatments of water and aqueous solution resulted from-bubble exchange interactions. These exchange interactions are mediated by the ordering of the water molecules

  6. 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.

  7. The mzTab Data Exchange Format: Communicating Mass-spectrometry-based Proteomics and Metabolomics Experimental Results to a Wider Audience*

    PubMed Central

    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

    2014-01-01

    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. PMID:24980485

  8. 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. PMID:24980485

  9. 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)

  10. 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.

  11. Scenarios for galaxy formation

    NASA Technical Reports Server (NTRS)

    Silk, Joseph

    1997-01-01

    The gravitational instability theory and its application to the origin of large scale structure are reviewed. The modeling of galaxy formation is described, from forwards and backwards perspectives. The emphasis is on the interactions between stellar and galactic formation.

  12. The formation of galaxies

    NASA Technical Reports Server (NTRS)

    Efstathiou, G.; Silk, J.

    1983-01-01

    Current models of galaxy formation are examined in a review of recent observational and theoretical studies. Observational data on elliptical galaxies, disk galaxies, luminosity functions, clustering, and angular fluctuations in the cosmic microwave background are summarized. Theoretical aspects discussed include the origin and early evolution of small fluctuations, matter and radiation fluctuations, the formation of large-scale structure, dissipationless galaxy formation, galaxy mergers, dissipational galaxy formation, and the implications of particle physics (GUTs, massive neutrinos, and gravitinos) for cosmology.

  13. Autonomous formation flight

    Microsoft Academic Search

    F. Giulietti; L. Pollini; M. Innocenti

    2000-01-01

    This article describes an approach to close-formation flight of autonomous aircraft. A standard LQ-based structure was synthesized for each vehicle and for formation position error control using linearized equations of motion and a lifting line model of the aircraft wake. We also consider the definition of a formation management structure, capable of dealing with a variety of generic transmission and

  14. BOREAS RSS-2 Extracted Reflectance Factors Derived from ASAS Imagery

    NASA Technical Reports Server (NTRS)

    Russell, C.; Hall, Forrest G. (Editor); Nickerson, Jaime (Editor); Dabney, P.; Kovalick, W.; Graham, D.; Bur, Michael; Irons, James R.; Tierney, M.

    2000-01-01

    The BOREAS RSS-2 team derived atmospherically corrected bidirectional reflectance factor means from multispectral, multiangle ASAS imagery for small homogeneous areas near several BOREAS sites. The ASAS imagery was acquired from the C-130 aircraft platform in 1994 and 1996. The data are stored 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-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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. NATIONAL SURFACE WATER SURVEY: EASTERN LAKE SURVEY, PHASE 1 (ELS-1), 1984 (ASCII TAPE)

    EPA Science Inventory

    The Eastern Lake Survey-Phase I (ELS-I), conducted in the fall of 1984, was the first part of a long-term effort by the U.S. Environmental Protection Agency known as the National Surface Water Survey. It was designed to synoptically quantify the surface water quality of the Unite...

  5. Mission Summary ASCII 4 January: 15 March 2012, Battle Pass Site, Wyoming Contact: Katja Friedrich,

    E-print Network

    : 10-15 LT, 17-22 UTC (upslope event) Author: Katja Friedrich Instrument status: Disdrometer CU01 Does): No changes IOP type: Single UWKA flight IOP Double flight IOP Single-generator, single-flight IOP Blowing

  6. Mission Summary ASCII 4 January: 15 March 2012, Battle Pass Site, Wyoming Contact: Katja Friedrich,

    E-print Network

    -01-16 1230 UTC END 2012-01-16 2245 UTC Author: Evan Kalina Instrument status: Disdrometer CU01 Down). IOP type: Single UWKA flight IOP Double flight IOP Single-generator, single-flight IOP Blowing Snow

  7. Mission Summary ASCII 4 January: 15 March 2012, Battle Pass Site, Wyoming Contact: Katja Friedrich,

    E-print Network

    20120118 2145 UTC END 20120119 0400 UTC Author: Evan Kalina Instrument status: Disdrometer CU01 Down. IOP type: Single UWKA flight IOP Double flight IOP Single-generator, single-flight IOP Blowing Snow

  8. Globular Cluster Formation

    E-print Network

    Keith M. Ashman

    2002-10-27

    The discovery of young globular clusters in merging galaxies and other environments provides an opportunity to study directly the process of globular cluster formation. Empirically it appears that globular cluster formation occurs preferentially in regions in which star formation occurs at a high rate and efficiency. Further, the interstellar medium in such regions is likely to be at a higher pressure than less active star-forming environments. An additional observational clue to the globular cluster formation process is that young globular clusters have little or no mass-radius relationship. In this paper I argue that high pressure and high star-formation efficiency are responsible for current globular cluster formation. I suggest that the precursors to globular clusters are molecular clouds and that the mass-radius relationship exhibited by such clouds is wiped out by a variable star formation efficiency.

  9. IDL Week 2: What we'll cover today

    E-print Network

    . To close a file: free_lun, lun #12;ASCII text: Pros and Cons Human readable Universal common format Can Subject to formatting errors #12;Reading in a free-format file Free-format ASCII files use whitespace readf an array subscript, the array will not be modified! #12;Free-format rules Rule #1: If reading

  10. Tropical cyclone formation

    SciTech Connect

    Montgomery, M.T.; Farrell, B.F. (Harvard Univ., Cambridge, MA (United States))

    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.

  11. Flash Open File Format

    NSDL National Science Digital Library

    Macromedia has released the file format specification for its Flash (discussed in the April 11, 1997 Scout Report) multimedia web tool. Flash allows web developers to create vector based graphics and animation. By making the format (.swf) available, Macromedia hopes to establish it as a standard for vector graphics and animation. The company claims it will "submit the format specification to a recognized Internet standards organization." In addition to providing the file format specification, the site provides Flash related news releases, a Flash FAQ, and a vector graphics white paper.

  12. GLOBAL STAR FORMATION REVISITED

    SciTech Connect

    Silk, Joseph [Physics Department, University of Oxford, 1 Keble Road, Oxford OX1 3RH (United Kingdom); Norman, Colin [Physics Department, Johns Hopkins University, 2400 North Charles Street, Baltimore, MD 21218 (United States)], E-mail: silk@astro.ox.ac.uk, 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.

  13. 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…

  14. Star formation Simon Goodwin

    E-print Network

    Crowther, Paul

    Star formation Simon Goodwin Dept Physics & Astronomy, University of Sheffield, Hounsfield Road, Sheffield, S3 7RH, UK. s.goodwin@sheffield.ac.uk 1 Abstract Stars are one of the most important consituents of the Universe, and understanding their formation is crucial to many areas of astrophysics. Stars form from dense

  15. 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…

  16. The plasmapause formation

    NASA Astrophysics Data System (ADS)

    Lemaire, J.

    The theory of plasmapause formation is examined. Particular attention is given to the role of magnetospheric fields in the inner magnetosphere, the noon-midnight and dawn-dusk asymmetries, plasma density distribution in the plasmasphere, plasmapause positions in the nightside sector and the daytime LT sector, the LT distribution of detached plasma elements, the growth rate of interchange instability, the formation of new density knees at each new enhancement in magnetospheric convection, and diamagnetic and finite-temperature effects. The ideal MHD theory for the formation of the plasmapause is considered.

  17. Amyloid formation: Interface influence

    NASA Astrophysics Data System (ADS)

    Hamley, Ian W.

    2010-09-01

    The aggregation of proteins into fibrils plays a crucial role in neurological conditions such as Parkinson's disease. Further insight into fibril formation has now been gained that reveals the effect of hydrophobic surfaces, including air.

  18. Formation of Hurricanes

    NSDL National Science Digital Library

    Amber Morgan

    2012-08-10

    This is a picture inquiry based lesson for students to explore the formation of hurricanes. Groups of three students will observe and explain trends found in a picture and share ideas with their peers.

  19. Understanding Earth: Coal Formation

    NSDL National Science Digital Library

    W.H. Freeman & amp; Co. Publishing

    Supplementary material from Understanding Earth (4th ed.), this short animation guides viewers through the formation of coal and its pathway through different grades. The animation is annotated with labels.

  20. Rethinking globular clusters formation

    NASA Astrophysics Data System (ADS)

    Renzini, Alvio

    This paper is aimed at emphasizing some of the main hints, constraints and difficulties we currently have in trying to understand how globular clusters formed, along with their multiple stellar generations, an issue that must be regarded as intimately connected to the formation process itself. Thus, the topics that are addressed include i) the required mass of the progenitor, ii) how to form new stars in an environment already crowded by a previous stellar generation, iii) how photometry and spectroscopy appear to suggest different formation processes for second generation stars, iv) whether dilution with pristine material may (or may not) be necessary for the formation of second generations, v) why the few clusters with multiple iron abundances are after all not so different from those that are homogeneous, and finally vi) why special environmental conditions may not be necessary for the formation of globular clusters with multiple stellar generations.

  1. Teaching Letter Formation.

    ERIC Educational Resources Information Center

    Graham, Steve; Madan, Avi J.

    1981-01-01

    The authors describe a remedial technique for teaching letter formation to students with handwriting difficulties. The approach blends traditional procedures (modeling, physical prompts, tracing, self correction, etc.) with cognitive behavior modification principles. (CL)

  2. 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.

  3. 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.

  4. Formation control for cooperative surveillance

    E-print Network

    Woo, Sang-Bum

    2009-05-15

    Constructing and maintaining a formation is critical in applications of cooperative control of multi-agent systems. In this research we address the formation control problem of generating a formation for a group of nonholonomic mobile agents...

  5. 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.

  6. Isolating Triggered Star Formation

    E-print Network

    Elizabeth J. Barton; Jacob A. Arnold; Andrew R. Zentner; James S. Bullock; Risa H. Wechsler

    2007-08-21

    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 select galaxy pairs that are isolated in their dark matter halos with respect to other massive subhalos (N=2 halos) and 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_Bj isolated 50 (30) kpc/h pairs exhibit star formation that is boosted by a factor of >~ 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. 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 triggered star formation in a cosmological context. (Abridged.)

  7. Format-Preserving Encryption

    NASA Astrophysics Data System (ADS)

    Bellare, Mihir; Ristenpart, Thomas; Rogaway, Phillip; Stegers, Till

    Format-preserving encryption (FPE) encrypts a plaintext of some specified format into a ciphertext of identical format—for example, encrypting a valid credit-card number into a valid credit-card number. The problem has been known for some time, but it has lacked a fully general and rigorous treatment. We provide one, starting off by formally defining FPE and security goals for it. We investigate the natural approach for achieving FPE on complex domains, the “rank-then-encipher” approach, and explore what it can and cannot do. We describe two flavors of unbalanced Feistel networks that can be used for achieving FPE, and we prove new security results for each. We revisit the cycle-walking approach for enciphering on a non-sparse subset of an encipherable domain, showing that the timing information that may be divulged by cycle walking is not a damaging thing to leak.

  8. Storm lag and related facies of the bioclastic limestones of the Eze-Aku Formation (Turonian), Nigeria

    NASA Astrophysics Data System (ADS)

    Banerjee, Indranil

    1981-10-01

    The predominantly siliclastic Eze-Aku Formation (Turonian) located in the southeastern Nigerian Basin contains scattered lenses and layers of bioclastic limestone which show three distinct facies: Facies 1 — Beds (0.2-1 m thick) of sparite-cemented grainstones grading laterally into cross-bedded medium sandstones, Facies 2 — Lenses (1-2 m thick, 0.1-2 km wide) of grainstones and wackestones within fine bioturbated silty sandstones. Facies 3 — Tabular units (1-2 m thick, 2-6 km wide) of wackestone within laminated black shale. Grainstones are interpreted as storm-lag deposits accumulated either at the margins of offshore bars (facies 1) or on the wide platform of bioturbated muddy sand located below the wave base (facies 2). Wackestones of facies 3 are believed to be deposited by high-density turbidity currents carrying shallow-water shells into the deeper basin. Wackestones of facies 2 are difficult to interpret but might have been deposited by smallscale storm-generated debris flows on a shallow platform.

  9. Wotsit's File Format Collection

    NSDL National Science Digital Library

    Wotsit's File Format Collection, provided by Paul Oliver, features a very large number of file formats. These include JPEG image files, wave sound files, Rich Text files, and common database and word-processing files such as Paradox and Wordperfect. Documents collected or linked at the site are primarily either original specifications from the creator or an improved version of the original. All of the specifications are very technical and are directed towards programmers. Users can subscribe to a mailing list for notification of site updates.

  10. Formation of Galactic Disks

    E-print Network

    S. Michael Fall

    2002-03-27

    We review progress in understanding the formation of galactic disks in the standard cosmogonic scenario involving gravitational clustering of baryons and dark matter and dissipative collapse of the baryons. This scenario accounts remarkably well for the observed properties of galactic disks if they have retained most of the specific angular momentum they acquired by tidal torques. Early simulations, which included cooling of the gas but not star formation and the associated feedback, indicated instead that most of the angular momentum of the baryons would be transferred to the dark matter. Recent simulations indicate that this angular-momentum problem can be solved partially, and in some cases entirely, by feedback and other effects.

  11. Formation of galaxies

    SciTech Connect

    Szalay, A.S.

    1984-12-01

    The present theories of galaxy formation are reviewed. The relation between peculiar velocities and the correlation function of galaxies points to the possibility that galaxies do not form uniformly everywhere. Scale invariant properties of the cluster-cluster correlations are discussed. Comparing the correlation functions in a dimensionless way, galaxies appear to be stronger clustered, in contrast with the comparison of the dimensional amplitudes of the correlation functions. Theoretical implications of several observations as Lyman-..cap alpha.. clouds, correlations of faint galaxies are discussed. None of the present theories of galaxy formation can account for all facts in a natural way. 29 references.

  12. Isolating Triggered Star Formation

    SciTech Connect

    Barton, Elizabeth J.; Arnold, Jacob A.; /UC, Irvine; Zentner, Andrew R.; /KICP, Chicago /Chicago U., EFI; Bullock, James S.; /UC, Irvine; Wechsler, Risa H.; /KIPAC, Menlo

    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 triggered star formation in a cosmological context.

  13. 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.

  14. Glueball formation in chromostatics

    Microsoft Academic Search

    Kimball A. Milton; Walter Wilcox

    1983-01-01

    Confinement and bag formation is demonstrated for SU(2) static gluons in a semi-classical model in which the leading logarithm improvement to the classical lagrangian is employed. The gluons are represented by static sources in the adjoint representation, and the fields are expanded in the algebra generated by the gluon charges. Restriction is made to the singlet representation by use of

  15. Wound-Periderm Formation

    Microsoft Academic Search

    Idit Ginzberg

    Herbivores, and particularly chewing insects, cause substantial damage to the plant. In addition to lost tissue, there are great concerns of pathogen invasion and water loss at the site of the attack. One of the plant’s defense strategies is the formation of wound periderm at the boundaries of the invaded or damaged region to isolate it from non-wounded healthy tissue.

  16. Oil Formation and Trapping

    NSDL National Science Digital Library

    Stephen Marshak

    This animation shows the successive stages in the formation of an oil reserve. In View 1, organic material settles, is buried, and is transformed by heat and pressure into oil. In View 2 an oil trap is formed: the area folds into an anticline, and oil migrates and accumulates in the anticline crest.

  17. FORMATION OF PHOTOCHEMICAL AEROSOLS

    EPA Science Inventory

    The objective was to develop a better understanding of smog aerosol formation with particular reference to haze in the Southern California area. This study combined laboratory work with ambient air studies. Counting of particles by light scattering was the principle physical tech...

  18. Hair follicle Formation of

    E-print Network

    Chuong, Cheng-Ming

    Hair follicle Formation of new follicles Bud Healed skin Hair bulge Open wound Epidermis a b Dermis 1950s and help to explain the controversy. What is the origin of the cells that make up these new hair follicles? Are they derived from existing hair follicles located at the wound edge

  19. Promoting habit formation

    Microsoft Academic Search

    Phillippa Lally; Benjamin Gardner

    2011-01-01

    Habits are automatic behavioural responses to environmental cues, thought to develop through repetition of behaviour in consistent contexts. When habit is strong, deliberate intentions have been shown to have a reduced influence on behaviour. The habit concept may provide a mechanism for establishing new behaviours, and so healthy habit formation is a desired outcome for many interventions. Habits also however

  20. Queen's Garden Formations

    USGS Multimedia Gallery

    Views along the Queen's Garden Trail in Bryce Canyon National Park. Bryce Canyon is a unique sandstone formation in southern Utah. It is home to a large number of hoodoos, which are oddly shaped pillars of rock that formed due to different erosion rates for the dolomite that caps them and the sands...

  1. 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)

  2. Bacterial formate hydrogenlyase complex

    PubMed Central

    McDowall, Jennifer S.; Murphy, Bonnie J.; Haumann, Michael; Palmer, Tracy; Armstrong, Fraser A.; Sargent, Frank

    2014-01-01

    Under anaerobic conditions, Escherichia coli can carry out a mixed-acid fermentation that ultimately produces molecular hydrogen. The enzyme directly responsible for hydrogen production is the membrane-bound formate hydrogenlyase (FHL) complex, which links formate oxidation to proton reduction and has evolutionary links to Complex I, the NADH:quinone oxidoreductase. Although the genetics, maturation, and some biochemistry of FHL are understood, the protein complex has never been isolated in an intact form to allow biochemical analysis. In this work, genetic tools are reported that allow the facile isolation of FHL in a single chromatographic step. The core complex is shown to comprise HycE (a [NiFe] hydrogenase component termed Hyd-3), FdhF (the molybdenum-dependent formate dehydrogenase-H), and three iron-sulfur proteins: HycB, HycF, and HycG. A proportion of this core complex remains associated with HycC and HycD, which are polytopic integral membrane proteins believed to anchor the core complex to the cytoplasmic side of the membrane. As isolated, the FHL complex retains formate hydrogenlyase activity in vitro. Protein film electrochemistry experiments on Hyd-3 demonstrate that it has a unique ability among [NiFe] hydrogenases to catalyze production of H2 even at high partial pressures of H2. Understanding and harnessing the activity of the FHL complex is critical to advancing future biohydrogen research efforts. PMID:25157147

  3. 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.

  4. Bacterial formate hydrogenlyase complex.

    PubMed

    McDowall, Jennifer S; Murphy, Bonnie J; Haumann, Michael; Palmer, Tracy; Armstrong, Fraser A; Sargent, Frank

    2014-09-23

    Under anaerobic conditions, Escherichia coli can carry out a mixed-acid fermentation that ultimately produces molecular hydrogen. The enzyme directly responsible for hydrogen production is the membrane-bound formate hydrogenlyase (FHL) complex, which links formate oxidation to proton reduction and has evolutionary links to Complex I, the NADH:quinone oxidoreductase. Although the genetics, maturation, and some biochemistry of FHL are understood, the protein complex has never been isolated in an intact form to allow biochemical analysis. In this work, genetic tools are reported that allow the facile isolation of FHL in a single chromatographic step. The core complex is shown to comprise HycE (a [NiFe] hydrogenase component termed Hyd-3), FdhF (the molybdenum-dependent formate dehydrogenase-H), and three iron-sulfur proteins: HycB, HycF, and HycG. A proportion of this core complex remains associated with HycC and HycD, which are polytopic integral membrane proteins believed to anchor the core complex to the cytoplasmic side of the membrane. As isolated, the FHL complex retains formate hydrogenlyase activity in vitro. Protein film electrochemistry experiments on Hyd-3 demonstrate that it has a unique ability among [NiFe] hydrogenases to catalyze production of H2 even at high partial pressures of H2. Understanding and harnessing the activity of the FHL complex is critical to advancing future biohydrogen research efforts. PMID:25157147

  5. Formation-flying interferometry

    Microsoft Academic Search

    Oliver P. Lay; Gary H. Blackwood

    2003-01-01

    There are many advantages to space-based interferometry, but monolithic, single-spacecraft platforms set limits on the collecting area and baseline length. These constraints can be overcome by distributing the optical elements of the interferometer over a system of multiple spacecraft flying in precise formation, opening up new realms of angular resolution and sensitivity. While the principles of interferometry are the same

  6. 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 or volcanic ash, and are thus more susceptible to windblown erosion. The Martian winds have actually been strong and relentless enough over time to strip the land in the bottom of this image of the material that once covered it, leaving it hard and bare to the eye.

  7. 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 are likely to experience severe mortality in upcoming decades due to natural and anthropogenic stresses. Consequently, this damage will lead to a collapse in reef formation and the maintenance of reef ecosystems in the near future. This study emphasizes the need for research into the conservation of key coral species.

  8. 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).

  9. Format( )MEDIC( )Input

    NASA Astrophysics Data System (ADS)

    Foster, K.

    1994-09-01

    This document is a description of a computer program called Format( )MEDIC( )Input. The purpose of this program is to allow the user to quickly reformat wind velocity data in the Model Evaluation Database (MEDb) into a reasonable 'first cut' set of MEDIC input files (MEDIC.nml, StnLoc.Met, and Observ.Met). The user is cautioned that these resulting input files must be reviewed for correctness and completeness. This program will not format MEDb data into a Problem Station Library or Problem Metdata File. A description of how the program reformats the data is provided, along with a description of the required and optional user input and a description of the resulting output files. A description of the MEDb is not provided here but can be found in the RAS Division Model Evaluation Database Description document.

  10. Formation of interpolymer complexes

    Microsoft Academic Search

    Eishun Tsuchida; Yoshihito Osada; Hiroyuki Ohno

    1980-01-01

    Interpolymer complex formations of poly(methacrylic acid) (PMAA) or poly(acrylic acid) (PAA) with oligocations as well as poly(ethylene oxide) (PEO), and poly-(N-vinyl-2-pyrrolidone of various chain lengths were studied. For the case of complexation between PMAA and oligocations, the standard free energy change for the complexation ?G° was found to be linearly dependent on the number of interacting sites, n. The stability

  11. 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 pressure levels and the occurrence of hail events.

  12. Text formatting by demonstration

    Microsoft Academic Search

    Brad A. Myers

    1991-01-01

    In text formatters such as troff, Scribe, and TEX, users write macro procedures to specify the desired visual appearance. In What-You-See-Is-What-You-Get text formatters, such as MacWrite and Microsoft Word, the formatting is specified by directly manipulating the text. However, some important functionality is lost in these systems since they are not programmable, For example, if the user wants to change

  13. Formation of Transient Lamellipodia

    PubMed Central

    Zimmermann, Juliane; Falcke, Martin

    2014-01-01

    Cell motility driven by actin polymerization is pivotal to the development and survival of organisms and individual cells. Motile cells plated on flat substrates form membrane protrusions called lamellipodia. The protrusions repeatedly appear and retract in all directions. If a lamellipodium is stabilized and lasts for some time, it can take over the lead and determine the direction of cell motion. Protrusions traveling along the cell perimeter have also been observed. Their initiation is in some situations the effect of the dynamics of the pathway linking plasma membrane receptors to actin filament nucleation, e.g. in chemotaxis. However, lamellipodia are also formed in many cells incessantly during motion with a constant state of the signaling pathways upstream from nucleation promoting factors (NPFs), or spontaneously in resting cells. These observations strongly suggest protrusion formation can also be a consequence of the dynamics downstream from NPFs, with signaling setting the dynamic regime but not initiating the formation of individual protrusions. A quantitative mechanism for this kind of lamellipodium dynamics has not been suggested yet. Here, we present a model exhibiting excitable actin network dynamics. Individual lamellipodia form due to random supercritical filament nucleation events amplified by autocatalytic branching. They last for about 30 seconds to many minutes and are terminated by filament bundling, severing and capping. We show the relevance of the model mechanism for experimentally observed protrusion dynamics by reproducing in very good approximation the repetitive protrusion formation measured by Burnette et al. with respect to the velocities of leading edge protrusion and retrograde flow, oscillation amplitudes, periods and shape, as well as the phase relation between protrusion and retrograde flow. Our modeling results agree with the mechanism of actin bundle formation during lamellipodium retraction suggested by Burnette et al. and Koestler et al. PMID:24505300

  14. Cave Formation: Biogeochemical Cycles

    NSDL National Science Digital Library

    This video explores the role of biogeochemical cycles in the formation of caves. It discusses a radical new theory that identifies sulfuric acid as a cave-forming agent. The video, adapted from a NOVA broadcast, identifies the source of the sulfuric acid, which, unlike carbonic acid, the typical cave-forming agent, does not readily form in nature. The segment is 5 minutes and forty seconds in length.

  15. Drumlin Formation Library Work

    NSDL National Science Digital Library

    Alison M Anders

    Students will individually produce a written introduction for a paper about the presence of drumlins on Mars - this introduction describes different models for drumlin formation on earth. To prepare for this assignment, students work in groups to do library research to find and read articles. The groups summarize their findings for each other. Each student then writes an introduction incorporating material from all the groups. Designed for a geomorphology course Uses geomorphology to solve problems in other fields

  16. 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

  17. 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.

  18. Swarm formations using the general formation potential function

    Microsoft Academic Search

    Shuzhi Sam Ge; Chency-Heng Fua; Wei-ming Liew

    2004-01-01

    This paper presents a method for synthesizing classes of potential functions, which corresponds to commonly used formations, from a general formation potential function by altering the values of a fixed set of parameters. These potential functions may then be used for formation control in swarms of agents. The properties of the potential functions are also examined in this paper. In

  19. 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)

  20. 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.

  1. Cluster Formation and the ISM

    E-print Network

    Ralph E. Pudritz; Jason D. Fiege

    1999-05-12

    We review the physics of star formation, and its links with the state of the ISM in galaxies. Current obervations indicate that the preferred mode of star formation is clustered. Given that OB associations provide the dominant energy input into the ISM, deep links exist between the ISM and star formation. We present a multi-scale discussion of star formation, and attempt to create an integrated vision of these processes.

  2. 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 (? = 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. PMID:23521246

  3. Adiabatic Halo Formation

    SciTech Connect

    Bazzani, A.; Turchetti, G.; Benedetti, C.; Rambaldi, S.; Servizi, G. [Physics Department University of Bologna, INFN Bologna, via Irnerio 46 40126 Bologna Italy (Italy)

    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.

  4. The formation of life

    E-print Network

    Robert L. Kurucz

    2000-11-10

    The formation of life is an automatic stage in the consolidation of rocky or "terrestrial" planets. The organic (=carbonaceous) matter, light elements, gases, and water must "float" toward the surface and the heavier metals must sink toward the center. Random processes in the molecular soup that fills microfractures in unmelted crust eventually produce self-replicating microtubules. In an appendix I suggest that some primordial crust remains because there is not enough consolidation energy to melt the whole planet. Energy is lost when iron planetesimals first partially melt and then coalesce to form the molten iron planetary core. Stony planetesimals accrete onto the surface of an already consolidated core.

  5. Modeling river delta formation

    PubMed Central

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

    2007-01-01

    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

  6. 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…

  7. Chapter 8: Model Initialization and Preprocessing CAPS -ARPS Version 4.0 214

    E-print Network

    Droegemeier, Kelvin K.

    for ARPS system elev.dat NCAR 5' and 1° ASCII data file dma_elev.dat NCAR 30'' ASCII data file The data fi, the Barnes multi-pass technique. This scheme allows for flexible user control over the analyzed terrain field files elev.dat and dma_elev.dat are stored in ASCII format and can be obtained through NCAR Data

  8. Star Cluster Formation and Star Formation: The Role of Environment and Star Formation Efficiencies

    E-print Network

    Uta Fritze

    2008-01-15

    Analyzing global starburst properties in various kinds of starburst and post-starburst galaxies and relating them to the properties of the star cluster populations they form, I explore the conditions for the formation of massive, compact, long-lived star clusters. The aim is to find out whether the relative amount of star formation that goes into star cluster formation as opposed to field star formation, and into the formation of massive long-lived clusters in particular, is universal or scales with star formation rate, burst strength, star formation efficiency, galaxy or gas mass, and whether or not there are special conditions or some threshold for the formation of star clusters that merit to be called globular clusters a few gigayears later.

  9. 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.

  10. The Planet Formation Imager

    NASA Astrophysics Data System (ADS)

    Kraus, S.; Buscher, D. F.; Monnier, J. D.; PFI Science, the; Technical Working Group

    2014-04-01

    Among the most fascinating and hotly-debated areas in contemporary astrophysics are the means by which planetary systems are assembled from the large rotating disks of gas and dust which attend a stellar birth. Although important work is being done both in theory and observation, a full understanding of the physics of planet formation can only be achieved by opening observational windows able to directly witness the process in action. The key requirement is then to probe planet-forming systems at the natural spatial scales over which material is being assembled. By definition, this is the so-called Hill Sphere which delineates the region of influence of a gravitating body within its surrounding environment. The Planet Formation Imager project has crystallized around this challenging goal: to deliver resolved images of Hill-Sphere-sized structures within candidate planet-hosting disks in the nearest star-forming regions. In this contribution we outline the primary science case of PFI and discuss how PFI could significantly advance our understanding of the architecture and potential habitability of planetary systems. We present radiation-hydrodynamics simulations from which we derive preliminary specifications that guide the design of the facility. Finally, we give an overview about the interferometric and non-interferometric technologies that we are investigating in order to meet the specifications.

  11. Egg Formation in Lepidoptera

    PubMed Central

    Telfer, William H.

    2009-01-01

    Reproductive biology in the Twentieth Century produced comprehensive descriptions of the mechanisms of egg formation in most of the major orders of insects. While many general principles of ovarian development and physiology emerged, every order turned out to have a set of its own special motifs. Discovery of the lepidopteran motifs is summarized in this essay. The emphasis is on developmental mechanisms, beginning with the early growth and differentiation of female germ cells and ending, after many turns in morphogenesis, physiology and biosynthesis, with eggs that are filled with yolk and encased in chorions. Examples of uniquely lepidopteran traits include the cellular composition of ovarian follicles, the number of tubular ovarioles in which they mature, the functions of cell-to-cell junctional complexes in their maturation, their use of glycosaminoglycans to maintain intercellular patency during vitellogenesis, the role of proton and calcium pumps in their ion physiology, a separate postvitellogenic period of water and inorganic ion uptake, and the fine structure and protein composition of their chorions. Discovery of this combination of idiosyncracies was based on advances in the general concepts and techniques of cell and molecular biology and on insights borrowed from studies on other insects. The lepidopteran ovary in turn has contributed much to the understanding of egg formation in insects generally. PMID:20050770

  12. Urbanization and Slum Formation

    PubMed Central

    Phua, Kai Hong

    2007-01-01

    The formation of slums need not be inevitable with rapid urbanization. Such an argument appears to be contradicted by evidence of large slum populations in a large number of developing countries and particularly in rapidly urbanizing regions like Asia. The evidence discussed suggests that city authorities faced with rapid urban development lack the capacity to cope with the diverse demands for infrastructural provision to meet economic and social needs. Not only are strategic planning and intervention major issues in agenda to manage rapid urbanization, but city governments are not effectively linking the economic development trajectory to implications for urban growth and, hence, housing needs. In the following discussion, a case study is presented in support of the argument that city governments have to first recognize and then act to establish the link that is crucial between economic development, urban growth, and housing. This is the agendum that has been largely neglected by city and national governments that have been narrowly focused on economic growth with the consequent proliferation of slum formation as a housing solution. PMID:17387618

  13. Deep Water Formation

    NASA Technical Reports Server (NTRS)

    Killworth, P. D.

    1984-01-01

    Some simple arguments on plumes of dense water and filling boxes were given. What determines the time for a large-scale environment to be modified by the injection of dense water at its edge is the mass flux, not the buoyancy flux. However, it is the denser buoyancy flux, when there are several competing plumes (e.g., the Mediterranean outflow versus the Denmark Strait outflow) that determines which plume will provide the bottom water for that ocean basin. It was noted that the obvious laboratory experiment (rotate a pie-shaped annulus, and heat/cool it on the surface) had never been performed. Thus, to some extent our belief that deep convection is somehow automatic at high latitudes to close off some ill-defined meridional circulation has never been tested. A summary of deep convection was given. The two fundamental formation mechanisms were shown. Of the two, it is open-ocean convection which forms the water which supplies the Denmark Strait overflow -- in all likelihood, as formation in the Greenland Sea remains stubbornly unobserved. But it is the slope convection which finally creates North Atlantic deep water, following the Denmark Strait overspill.

  14. LISA satellite formation control

    NASA Astrophysics Data System (ADS)

    Bik, J. J. C. M.; Visser, P. N. A. M.; Jennrich, O.

    The joint ESA-NASA Laser Interferometer Space Antenna (LISA) mission consists of a triangular formation of three satellites aiming at detecting gravitational waves. In linear approximation the LISA satellites describe a circle around a reference point, maintaining a fixed position with respect to each other. The reference point, the center of the triangle, orbits the Sun in a circular orbit, trailing the Earth at twenty degrees. In reality the distance between the satellites will vary by about one to two percent and the angle between the arms of the antenna will vary by about 0.5° over the course of one year for the nominal LISA satellite configuration. For measurement accuracy it is desirable that the pointing offset of the telescopes be kept small. This makes it necessary to actuate the telescopes or to control the formation. It was assumed that the LISA satellites are equipped with six ?N engines that would allow to keep the two cubical proof masses within each satellite in almost perfect free fall. It was found that control forces up to about 700 ?N are required for maintaining the absolute triangular LISA formation, leading to unacceptable excursions of the proof masses from free fall. However, these forces compensate predominantly very low frequency variations of the arm lengths and angles of the triangle, which are then to be compensated by the telescope actuators. The variations are outside the aimed LISA measurement bandwidth (10 -4-0.1 Hz). In addition, the effect of thruster noise, orbit determination errors and orbit injection errors was examined. The effect of these error sources on the arm lengths and orientation angles between the LISA satellites was assessed both in open loop and in closed loop, where the closed loop was based on a proportional-derivative (PD) controller. It was found that orbit determination errors of the order of a few km in position and a few mm/s in velocity lead to negligible closed loop control forces. In addition, orbit injection errors of the order of 10 km in position and 1 cm/s in velocity could be eliminated after a few days when thrusting at levels of 200-500 ?N. Even for a high estimated level of thruster noise below 10 -4 Hz (equivalent to about 2 ?N random thrusts once an hour), the closed loop controller effectively reduced the effect on the angles of the triangle to below 30 nrad.

  15. Chorionic Villi Formation

    NSDL National Science Digital Library

    PhD Jack D Thatcher (West Virginia School of Osteopathic Medicine Structural Biology)

    2010-11-29

    This FlashTM animation depicts morphogenesis of chorionic villi. It begins by displaying a cross section through the three layers of the chorion, with a maternal sinusoid expanding through the syncyciotrophoblast. Clicking causes the lesson to progress through a stepwise display of the formation of stem, terminal, primary, secondary and tertiary villi, with the intervillous space and outer trophoblastic shell. The lesson ends with an explanation of how the chorionic villi of the placenta mediate diffusion between the fetal and maternal circulatory systems. A back button allows users to jump to previous scenes, a rate button allows them to toggle between fast and slow modes, and a text button allows them to toggle explanatory text on and off.

  16. Pine Island Iceberg Formation

    NSDL National Science Digital Library

    Lori Perkins

    2002-01-10

    This animation is a sequence showing the formation of the Pine Island iceberg and the glacial seaward flow upstream from the crack. It is a series of MISR images from the Terra satellite on top of the continental Radarsat view of Antarctica. The Pine Island Glacier is the largest discharger of ice in Antarctica and the continents fastest moving glacier. Even so, when a large crack formed across the glacier in mid 2000, it was surprising how fast the crack expanded, 15 meters per day, and how soon the resulting iceberg broke off, mid-November, 2001. This iceberg, called B-21, is 42 kilometers by 17 kilometers and contains seven years of glacier outflow released to the sea in a single event.

  17. Glass formation in microgravity

    NASA Technical Reports Server (NTRS)

    Ray, C. S.; Day, D. E.

    1987-01-01

    An account is given of containerless glass-forming experiments conducted aboard the Space Shuttle in 1985, using a single-axis acoustic levitator furnace apparatus. An attempt was made to obtain quantitative evidence for the suppression of heterogeneous nucleation/crystallization in containerless melts under microgravity conditions, as well as to study melt homogenization in the absence of gravity-driven convection and assess the feasibility of laser fusion target glass microsphere preparation with a microgravity apparatus of the present type. A ternary calcia-gallia-silica glass thus obtained indicated a 2-3-fold increase in glass-formation tendency for this material composition in microgravity, by comparison with 1g.

  18. Dityrosine formation in calmodulin

    SciTech Connect

    Malencik, D.A.; Anderson, S.R.

    1987-02-10

    Ultraviolet (280-nm) irradiation of bovine brain calmodulin results in calcium-dependent changes in its fluorescence emission spectrum. These consist of a decline in the intrinsic tyrosine fluorescence of the protein and the appearance of a new emission maximum at 400 nm. Chromatography of irradiated calmodulin, using Ultrogel AcA 54 and phenyl-agarose columns, yields several distinctive fractions. One of these, representing 2.8% of the total recovered protein and 53% of the total fluorescence emission at 400 nm, was selected for detailed characterization. Analyses performed on acid hydrolysates reveal the presence of dityrosine, a derivative of tyrosine known for its fluorescence near 400 nm, at the level of 0.59-0.89 mol per 16,700 g of protein. Sodium dodecyl sulfate gel electrophoresis experiments demonstrate two components of apparent molecular weights 14,000 (80%) and 16,000 (20%). Observations on the effects of UV irradiation on the thrombic fragments of calmodulin and on related calcium binding proteins (rabbit skeletal muscle troponin C, bovine cardiac troponin C, and parvalbumin) support the interpretation that dityrosine formation in calmodulin results from the intramolecular cross-linking of Tyr-99 and Tyr-138. The dityrosine-containing photoproduct of calmodulin is unable to stimulate the p-nitrophenyl phosphatase activity of calcineurin under standard assay conditions. Smooth muscle myosin light chain kinase binds the derivative about 280-fold less effectively than it binds native calmodulin. Of several metal ions tested, only Cd/sup 2 +/ approaches Ca/sup 2 +/ in its ability to promote the appearance of the 400-nm emission band during UV irradiation of calmodulin. Mn/sup 2 +/ and Cu/sup 2 +/ appear to inhibit dityrosine formation.

  19. Cellular pattern formation

    NASA Astrophysics Data System (ADS)

    Jiang, Yi

    This thesis studies the formation and evolution of cellular patterns in foams and living organisms using the extended large-Q Potts model. Specific problems include grain growth, foam drainage, foam rheology, and patterning and cell sorting in the mound phase of the slime mode Dictyostelium discoideum. In a wide range of cellular materials, surface-energy-driven diffusion leads to boundary motion which causes some grains to expend and others to shrink. Two-dimensional large-Q Potts model simulation of the evolution of a disordered cluster developed from a hexagonal grain array with a defect shows that abnormal grain growth can occur without strong anisotropy of surface energy. The grains at the boundary of the disordered cluster reach a special scaling state with no scale change. In three-dimensional liquid foams, drainage occurs due to gravity. Large-Q Potts model simulations, extended to include gravity in three dimensions, agree with both experimental and analytical results for various kinds of foam drainage, and also predict new phenomena. Foams exhibit a unique rheological transition from solid-like to fluid-like. Simulations using the large-Q Potts model, extended to apply shear to a two-dimensional foam, show three different types of hysteresis in foam's stress-strain relationship, which correspond to the elastic, viscoelastic and viscous fluid properties. This wide-ranging mechanical response depends on the structure and dynamics of local topological rearrangement of foam cells. Biological tissues resemble foams and the large-Q Potts model can also simulate sorting in biological cell aggregates. In Dictyostelium mound, two types of cells are initially randomly distributed. In time, one cell type sorts to form a tip. Simulations show that both differential adhesion and chemotaxis are required for sorted tip formation. With only differential adhesion, no tip forms. With only chemotaxis, a tip forms containing both cell types. Thus simulations can provide a method to determine the processes necessary for biological patterning.

  20. 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

  1. Fracture corridors as seal-bypass systems in siliciclastic reservoir-cap rock successions: Field-based insights from the Jurassic Entrada Formation (SE Utah, USA)

    NASA Astrophysics Data System (ADS)

    Ogata, Kei; Senger, Kim; Braathen, Alvar; Tveranger, Jan

    2014-09-01

    Closely spaced, sub-parallel fracture networks contained within localized tabular zones that are fracture corridors may compromise top seal integrity and form pathways for vertical fluid flow between reservoirs at different stratigraphic levels. This geometry is exemplified by fracture corridors found in outcrops of the Jurassic Entrada Formation in Utah (USA). These fracture corridors exhibit discolored (bleached) zones, interpreted as evidence of ancient fracture-enhanced circulation of reducing fluids within an exhumed siliciclastic reservoir-cap rock succession. Extensive structural and stratigraphic mapping and logging provided fracture data for analysis with respect to their occurrence and relationships to larger faults and folds. Three types of fracture corridors, representing end-members of a continuum of possibly interrelated structures were identified: 1) fault damage zone including segment relays; 2) fault-tip process zone; and 3) fold-related crestal-zone fracture corridors. The three types exhibit intrinsic orientations and patterns, which in sum define a local- to regional network of inferred vertical and lateral, high-permeability conduits. The results from our analysis may provide improved basis for the evaluation of trap integrity and flow paths across the reservoir-cap rock interface, applicable to both CO2 storage operations and the hydrocarbon industry.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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).

  16. “Translating” between survey answer formats?

    PubMed Central

    Dolnicar, Sara; Grün, Bettina

    2013-01-01

    Survey research remains the most popular source of market knowledge, yet researchers have not yet established one consistent technique for measuring responses. Some market research companies offer respondents two answer options; others five or seven. Some answer formats use middle points on the answer scales, others do not. Some formats verbalize all answer options, some only the endpoints. The wide variety of answer formats that market research companies and academic researchers use makes comparing results across studies virtually impossible. This study offers guidance for market researchers by presenting empirical translations for the answer formats they most commonly use, thus enabling easier comparisons of results. PMID:24926110

  17. GenBank at Los Alamos: User manual, training guide, and reference manual for the ASCII AWB

    SciTech Connect

    Reese, G.C.; Keen, G.M.; Gilna, P.; Cinkosky, M.J.

    1993-03-15

    The GenBank project at Los Alamos collects nucleotide sequence submissions from the biological research community. This work includes the processing of data received in several different forms as well as maintenance and quality control on those submissions. This manual explains the procedures involved in that work for both Los Alamos GenBank staff and off-site users. The GenBank database stores annotated DNA sequences. This manual contains the procedures for depositing these sequences into the database. There are two ways to do this. Either the sequence arrives at GenBank as a submission and is entered by the database staff or the sequence is directly entered by an off-site user. The Annotator's WorkBench (AWB), which is a database browsing and editing tool, is used in both cases. This manual is for GenBank staff and off-site users of the GenBank database at the Los Alamos National Laboratory. It contains an introduction and tutorials for AWB, as well as procedures for entering sequences either as submissions or as data directly deposited by an off-site user. Instructions for all of these are found in Chapters 2 through 4. The introduction to AWB is in Chapter 2. Instructions for submission handling are in Chapter 3. Instructions for entering sequence information are in Chapter 4. Off-site users should look at section 4.3 for instructions on entering a sequence. In addition, the manual describes various in-house curatorial tasks that are part of maintaining the database, as well as the procedures and conventions for annotating sequences. The procedures for annotation and review are in Chapters 5 and 6. The description of in-house curator's tasks is in Chapter 7. The appendices contain: Annotation conventions, two reference chapters on AWB and other utility programs, a complete list of all the forms, fields, and commands in AWB and descriptions of other (non-AWB) software utilities used by database staff.

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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 dark, at constant temp 20Ë? C (+/-2Ë? C) and with intermittent aeration. During incubation, the mineralization was quantified and soil samples were analyzed for the presence of both "biogenic residues" and remaining 2,4-D. Mineralization of 2,4-D in both experiments was very high. However, the 14CO2 evolution was higher from carboxyl-14C 2,4-D than from 14C-ring 2,4-D. After 7 days of incubation, 30% of initial amount of 14C in soil contaminated with 14C-ring 2,4-D was mineralized, whereas 40% of total radioactivity was evolved as CO2after 4 days from soil incubated with 14C-carboxyl 2,4-D. The amount of extractable 2,4-D residues was very low in both experiments (14C-ring 2,4-D: 2% and 14C-carboxyl 2,4-D: 1%). The soil incubated with 14C-ring 2,4-D contained 60% of "non-extractable" residues of 2,4-D after 7 days, while the amount of these residues in soil contaminated with 14C-carboxyl 2,4-D reached 50% of the initial radioactivity in the tested system 4 days after application. More "biogenic residues" were formed in soil spiked with 14C-U-ring 2,4-D (10%) than in soil with carboxyl 14C 2,4-D (7%). Both 2,4-D and CO2-derived C were incorporated mainly into microbial amino acids (9.5% at day 7 and 7.0% at day 4, respectively). After 7 days of incubation, 0.5% of initial applied radioactivity in system was found in microbial lipids in the soil contaminated with 14C-ring 2,4-D. Only 0.1% of the total radioactivity was incorporated into lipids in soil treated with 14C-carboxyl 2,4-D on day 4 after application. Thin Layer Chromatography identified the microbial lipids containing the radioactivity as phosphatidylethanolamine, a phospholipid typical for microorganisms. The amount of microbial lipids (which corresponds to phospholipids) in both cases decreased with time; this can be explained by the death of the microbial biomass. To the best of our knowledge, this is the first report on the formation of &qu

  3. Bead lightning formation

    SciTech Connect

    Ludwig, G.O.; Saba, M.M.F. [Associated Plasma Laboratory, National Space Research Institute, 12227-010, Sao Jose dos Campos, SP (Brazil); Division of Space Geophysics, National Space Research Institute, 12227-010, Sao Jose dos Campos, SP (Brazil)

    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.

  4. 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.

  5. 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…

  6. 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?

  7. Triglycerides and gallstone formation.

    PubMed

    Smelt, A H M

    2010-11-11

    Changes in bile acid (BA) metabolism and gallbladder function are critical factors in the pathogenesis of gallstones. Patients with hypertriglyceridemia (HTG) - often overweight and insulin resistant - are at risk for gallstone disease. The question arises whether HTG itself contributes to gallstone formation or whether gallstone disease only associates with this disorder. Triglycerides are formed in response to fluxes of non-esterified fatty acids and glucose. Hypertriglyceridemia results from either overproduction of triglycerides by the liver, impaired lipolysis or a combination of both. Hyperinsulinemia, as observed in the insulin resistant state, stimulates very low-density lipoprotein (VLDL)-triglyceride synthesis. Peroxisome proliferator-activated receptors (PPARs), liver X receptors (LXRs), farnesoid X receptor (FXR) and hepatocyte nuclear factor 4? (HNF4?) are the nuclear receptors involved in the regulation of lipogenesis. Microsomal triglyceride transfer protein (MTP) is involved in the production of VLDL and its activation is also under control of transcription factors as FXR and Forkhead box-O1 (FoxO1). Triglyceride and BA metabolism are linked. There is an inverse relationship between bile acid fluxes and pool size and VLDL production and SHP (small heterodimer partner) and FXR are the link between BAs and TG metabolism. BAs are also ligands for FXR and G-protein-coupled receptors, such as TGR5. FXR activation by BAs suppresses the expression of MTP, transcription factor sterol regulatory element binding protein (SREBP)-1c and other lipogenic genes. LXRs stimulate lipogenesis whereas FXRs inhibit the metabolic process. Synthesis of BAs from cholesterol occurs either via the classical pathway (7?-hydroxylation of cholesterol; CYP7A1) or via the alternate pathway (CYP39A1 or CYP7B1). BAs induce FXR, which inhibits CYP7A1 transcription by activation of SHP and inhibition of HNF4? transactivation. Bile composition (supersaturation with cholesterol), gallbladder dysmotility, inflammation, hypersecretion of mucin gel in the gallbladder and slow large intestinal motility and increased intestinal cholesterol absorption may contribute to the pathogenesis of cholesterol gallstones. In HTG patients supersaturated bile may be related to the presence of obesity rather than to HTG itself. Contraction and relaxation of the gallbladder are regulated by neuronal, hormonal and paracrine factors. Postprandial gallbladder emptying is regulated by cholecystokinin (CCK). Poor postprandial gallbladder contraction may be due to the magnitude of the CCK response and to the amount of CCK receptors in the gallbladder smooth muscle cells. In the fasting state gallbladder motility is associated with the intestinal migrating motor complex (MMC) activity and with elevated plasma motilin levels. Fibroblast growth factor (FGF19), produced on arrival of bile acids in the ileum, is also important for gallbladder motility. Gallbladder motility is impaired in HTG patients compared to BMI matched controls. There is evidence that the gallbladder in HTG is less sensitive to CCK and that this sensitivity improves after reversal of high serum TG levels by use of TG lowering agents. In hypertriglyceridemia TG lowering therapy (fibrates or fish-oil) is essential to prevent cardiovascular disease and pancreatitis. Fibrates, however, also increase the risk for cholelithiasis by increasing biliary cholesterol saturation and by reduction of bile acid synthesis. On the other hand fish-oil decreases biliary cholesterol saturation. Fish-oil may increase bile acid synthesis by activation of 7alpha-hydroxylase and may inhibit VLDL production and secretion through activation of nuclear factors and increased apoB degradation. In HTG patients, gallbladder motility improves during bezafibrate as well as during fish-oil therapy. The question remains whether improvement of gallbladder motility and increased lithogenicity of bile by bezafibrate therapy counteract each other or still result in gallstone formation in HTG patients. PMID:20699090

  8. The Principal as Formative Coach

    ERIC Educational Resources Information Center

    Nidus, Gabrielle; Sadder, Maya

    2011-01-01

    Formative coaching, an approach that uses student work as the foundation for mentoring and professional development, can help principals become more effective instructional leaders. In formative coaching, teaches and coaches analyze student work to determine next steps for instruction. This article shows how a principal can use the steps of the…

  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 w...

  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 ...

  11. Accretion processes in star formation

    Microsoft Academic Search

    Lee Hartmann

    1998-01-01

    This volume reviews our current knowledge of the processes governing the formation of stars, from the collapse and fragmentation of cold molecular gas clouds through the formation and evolution of disks which can form planets. It provides an especially timely reference for understanding recent discoveries of extrasolar planets and new direct evidence for protoplanetary disks around young stars. Each topic

  12. New Frontiers in Formative Assessment

    ERIC Educational Resources Information Center

    Noyce, Pendred E., Ed.; Hickey, Daniel T., Ed.

    2011-01-01

    "Formative assessment is a powerful learning tool that is too seldom, too haphazardly, and too ineffectively used in the United States," Pendred E. Noyce writes in the introduction to this volume. "The purpose of this book is to delve into why this is so and how it can be changed." Formative assessment involves constantly monitoring student…

  13. Science Sampler: Formative assessment guideposts

    NSDL National Science Digital Library

    Carlos Ayala

    2005-01-01

    A formative assessment can provide a snapshot of what a student knows and is able to do. Use this approach to close the gap between what is known and what needs to be known through informative feedback. Explore the use of formative assessments with navigational help from these six guideposts.

  14. 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. PMID:25367282

  15. Formation of the solar system

    Microsoft Academic Search

    C. Hayashi; K. Nakazawa; Y. Nakagawa

    1985-01-01

    The overall evolution of the solar system is discussed in terms of what is called the Kyoto model. Starting from the formation of the solar nebula, a multistep process is followed in detail, including growth and sedimentation of dust grains in the nebula, formation of planetesimals due to fragmentation of a dust layer, radial migration and accumulation of planetesimals to

  16. 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.

  17. Kinetic constraints on core formation

    Microsoft Academic Search

    C. Holzapfel; D. C. Rubie; D. J. Frost

    2003-01-01

    According to recent models of core formation, a metallic liquid equilibrated in an early magma ocean and subsequently descended through the crystalline lower mantle to form the protocore. In this study we are investigating the extent to which the metal would further equilibrate with crystalline material of the lower mantle given reasonable time scales of core formation. For this purpose,

  18. Brane Decay and Defect Formation

    SciTech Connect

    Stoica, Horace [Theoretical Physics, Blackett Laboratory, Imperial College, London SW7 2AZ (United Kingdom)

    2007-11-20

    Topological defects are generically expected to form in models of brane inflation. Brane-anti-brane annihilation provides a way to gracefully end inflation, and the dynamics of the tachyon field results in defect formation. The formation of defects has been studied mainly from the brane world-volume point of view, but the defects are themselves lower-dimensional branes, and as a result they couple to bulk fields. To investigate the impact of bulk fields on brane defect formation, we construct a toy model that captures the essential features of the tachyon condensation with bulk fields. In this toy model, we study the structure of defects and simulate their formation and evolution on a lattice. We find that while bulk fields do not have a significant effect on defect formation, they drastically influence the subsequent evolution of the defects, as they re-introduce long-range interactions between them.

  19. Defect formation with bulk fields

    SciTech Connect

    Moore, Guy D.; Stoica, Horace [Department of Physics, McGill University, 3600 University Street, Montreal QC H3A 2T8 (Canada)

    2006-09-15

    It has recently been realized that brane-antibrane annihilation (a possible explanation for ending inflation) may result in defect formation, due to the dynamics of the tachyon field. Studies of this possibility have generally ignored the interaction of the brane fields with fields in the bulk; recently it has been argued [G. Dvali and A. Vilenkin, J. Cosmol. Astropart. Phys. 03 (2004) 010.] that interactions with bulk fields suppress or even eliminate defect formation. To investigate the impact of bulk fields on brane defect formation, we construct a toy model that captures the essential features of the tachyon condensation with bulk fields. We study the structure of defects in this toy model, and simulate their formation and evolution on the lattice. We find that, while the energetics and interactions of defects are influenced by the size of the extra dimension and the bulk-brane coupling, the bulk-brane coupling does not prevent the formation of a defect network.

  20. 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], calcrete in paleosols, and abundant mud cracks evidencing ephemeral flow in streams) and biology (low floristic diversity, xeromorphic plant physiognomies). ?? 2006 Elsevier B.V. All rights reserved.

  1. Formation of interstellar anions

    NASA Astrophysics Data System (ADS)

    Senent, Maria Luisa

    2012-05-01

    Formation of interstellar anions: M.L. Senent. The recent detection of negative charged species in the ISM1 has instigated enthusiasm for anions in the astrophysical community2. Many of these species are new and entail characterization. How they are formed in astrophysical sources is a question of major relevance. The anion presence in ISM was first predicted theoretically on the basis of electron affinities and on the negative linear chain molecular stabilities. Although very early, they were considered in astrochemical models3-4, their discovery is so recent because their abundances seem to be relatively low. These have to be understood in terms of molecular stabilities, reaction probabilities and radiative and collisional excitations. Then, we present our theoretical work on even carbon chains type Cn and CnH (n=2,4,6) focused to the understanding of anion abundances. We use highly correlated ab initio methods. We performed spectroscopic studies of various isomers that can play important roles as intermediates5-8. In previous papers9-10, we compared C2H and C2H- collisional rates responsible for observed line intensities. Actually, we study hydrogen attachment (Cn +H ? CnH and Cn- +H ? CnH-) and associative detachment processes (Cn- +H ? CnH +e-) for 2, 4 and 6 carbon atom chains11. [1] M.C.McCarthy, C.A.Gottlieb, H.Gupta, P.Thaddeus, Astrophys.J, 652, L141 (2006) [2] V.M.Bierbaum, J.Cernicharo, R.Bachiller, eds., 2011, pp 383-389. [3] A. Dalgarno, R.A. Mc Cray, Astrophys.J,, 181, 95 (1973) [4] E. Herbst E., Nature, 289, 656 (1981); [5] H.Massó, M.L.Senent, P.Rosmus, M.Hochlaf, J.Chem.Phys., 124, 234304 (2006) [6] M.L.Senent, M.Hochlaf, Astrophys. J. , 708, 1452(2010) [7] H.Massó, M.L.Senent, J.Phys.Chem.A, 113, 12404 (2009) [8] D. Hammoutene, M.Hochlaf, M.L.Senent, submitted. [9] A. Spielfiedel, N. Feautrier, F. Najar, D. ben Abdallah, F. Dayou, M.L. Senent, F. Lique, Mon.Not.R.Astron.Soc., 421, 1891 (2012) [10] F.Dumouchel, A, Spielfieldel , M.L.Senent, N.Feautrier, Chem. Phys. Lett., 533, 6 (2012) [11] M.L.Senent, M.Hochlaf, submitted

  2. Star Formation Through Cosmic Time

    NASA Astrophysics Data System (ADS)

    Dopita, Michael A.

    2007-05-01

    I will review the literature on the star formation history of the Universe, from the first stars up to the current day. The first (population III) stars appear to be responsible for the re-ionization of the Universe, and for seeding the inter-galactic medium with heavy elements, facilitating the formation of subsequent generations. There are now many lines of evidence from sub-mm galaxies, deep surveys, and from steep-spectrum radio sources to suggest that the collapse of massive galaxies and the formation of central massive black holes occurred surprisingly early in time. These objects enjoyed galaxy-wide starbursts, were very rapidly enriched in heavy elements, and rapidly became very dusty. Relativistic jets from the active nuclei seem to have provided an important means of terminate the initial burst of star formation in these massive galaxies, though possibly accompanied by large amounts of not so quiescent shock-induced star formation. Subsequently, the massive galaxies have evolved passively (or nearly so, modulo a merger or two) to form the ellipticals and cD galaxies well distinguished by their color (`red and dead') in the SDSS data. In less dense environments, star formation proceeded more slowly through disk galaxies. With time only smaller and smaller fragments having high rates of specific star formation, until today only the dwarf irregular galaxies have high gas to star ratios. This process is frequently referred to as `down-sizing'.

  3. 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

  4. 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.

  5. Treating tar sands formations with karsted zones

    DOEpatents

    Vinegar, Harold J. (Bellaire, TX); Karanikas, John Michael (Houston, TX)

    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.

  6. Formation of the First Star Clusters

    E-print Network

    Klessen,Ralf

    Formation of the First Star Clusters Ralf Klessen Zentrum für Astronomie der Universität Heidelberg-Hsu Wang ... many collaborators abroad! #12;First star formation agenda #12;Star cluster formation First of molecular clouds Star cluster formation First star formation Magnetic fields in the primordial universe

  7. Tooth formation - delayed or absent

    MedlinePLUS

    Specific diseases can affect tooth shape, tooth color, time of appearance, or tooth absence. Delayed or absent tooth formation can result from many different conditions, including: Apert syndrome Cleidocranial ...

  8. Marmoryen Formation (marble) STORETVEIT GROUP

    E-print Network

    Fossen, Haakon

    ) STORETVEIT GROUP Minor Bergen Arc Paradis Formation (green polymict congl.) Deformed saussurite gabbro, gabbro-pegmatite, basic/acidic dykes NORDÃ?SVATN COMPLEX Fine-grained amphibolite, mylonitic in most

  9. Use-driven concept formation

    E-print Network

    Roberts, Jennifer M. (Jennifer Marie)

    2010-01-01

    When faced with a complex task, humans often identify domain-specific concepts that make the task more tractable. In this thesis, I investigate the formation of domain-specific concepts of this sort. I propose a set of ...

  10. Sandstone Formations in Capitol Reef

    USGS Multimedia Gallery

    Capitol Reef is primarily made up of sandstone formations within the Waterpocket Fold, monocline that extends nearly 100 miles. A monocline is a step-like fold in rock strata that can resemble an enormous wrinkle in the earth....

  11. Formation of the Solar System

    NSDL National Science Digital Library

    Joshua Barnes

    This chapter from an online astronomy course briefly describes the formation of the solar system from an accretionary disk. Links to additional resources, a homework assignment, and a quiz are included.

  12. Progress in Giant Planet Formation

    NASA Astrophysics Data System (ADS)

    Boss, A. P.

    Two very different mechanisms have been proposed for the formation of the gas and ice giant planets. The conventional explanation for the formation of gas giant planets, core accretion, presumes that a gaseous envelope collapses upon a roughly 10 Earth-mass, solid core that was formed by the collisional accumulation of planetary embryos orbiting in a gaseous disk. The more radical explanation, disk instability, hypothesizes that the gaseous portion of protoplanetary disks undergoes a gravitational instability, leading to the formation of self-gravitating clumps, within which dust grains coagulate and settle to form cores. Core accretion appears to require several million years or more to form a gas giant planet, implying that only long-lived disks would form gas giants. Disk instability, on the other hand, is so rapid (thousands of years), that gas giants could form in even the shortest-lived disks. Core accretion has severe difficulty in explaining the formation of the ice giant planets, unless two extra protoplanets are formed in the gas giant planet region and thereafter migrate outward. Recently, an alternative mechanism for ice giant planet formation has been proposed, based on observations of protoplanetary disks in the Orion nebula cluster: disk instability leading to the formation of four gas giant protoplanets with cores, followed by photoevaporation of the disk and gaseous envelopes of the protoplanets outside about 10 AU by a nearby OB star, producing ice giants. In this scenario, Jupiter survives unscathed, while Saturn is a transitional planet. These two basic mechanisms have very different predictions for gas and ice giant extrasolar planets, both in terms of their frequency and epoch of formation, suggesting a number of astronomical tests which could determine the dominant mechanism for giant planet formation.

  13. 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.

  14. Carbothermic formation of boron nitride

    Microsoft Academic Search

    A. Aydo?du; N. Sevinç

    2003-01-01

    Formation of boron nitride by reaction of boric oxide with carbon and nitrogen was studied. It was found from the results of experiments conducted by holding B2O3-activated C mixtures under a flowing nitrogen atmosphere that formation of boron nitride was complete in 120 min at 1500 °C. After cleaning the reaction product from the ash of the activated carbon and from

  15. The Epoch of Galaxy Formation

    Microsoft Academic Search

    C. M. Baugh; S. Cole; C. S. Frenk; C. G. Lacey

    1997-01-01

    We use a semi-analytic model of galaxy formation in hierarchical clustering\\u000atheories to interpret recent data on galaxy formation and evolution, focussing\\u000aprimarily on the recently discovered population of Lyman-break galaxies at\\u000a$z\\\\simeq 3$. For a variety of cold dark matter (CDM) cosmologies we construct\\u000amock galaxy catalogues subject to identical selection criteria to those applied\\u000ato the real data.

  16. 47 CFR 64.2329 - Format.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...telephone exchange service to a requesting directory publisher in the format the publisher...subscriber list information in the format the directory publisher specifies, the carrier shall...the publisher's request, inform the directory publisher that the requested format...

  17. 47 CFR 64.2329 - Format.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...telephone exchange service to a requesting directory publisher in the format the publisher...subscriber list information in the format the directory publisher specifies, the carrier shall...the publisher's request, inform the directory publisher that the requested format...

  18. 47 CFR 64.2329 - Format.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...telephone exchange service to a requesting directory publisher in the format the publisher...subscriber list information in the format the directory publisher specifies, the carrier shall...the publisher's request, inform the directory publisher that the requested format...

  19. 47 CFR 64.2329 - Format.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...telephone exchange service to a requesting directory publisher in the format the publisher...subscriber list information in the format the directory publisher specifies, the carrier shall...the publisher's request, inform the directory publisher that the requested format...

  20. 47 CFR 64.2329 - Format.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...telephone exchange service to a requesting directory publisher in the format the publisher...subscriber list information in the format the directory publisher specifies, the carrier shall...the publisher's request, inform the directory publisher that the requested format...

  1. Gypsum Layer in Spearfish Formation, SD

    USGS Multimedia Gallery

    Spearfish Formation near Spearfish, SD. The Spearfish Formation is a red, silty shale with interbedded red sandstone and siltstone. The formation contains massive gypsum deposits, which is the white layer in the photograph....

  2. Formative Evaluation in the Performance Context.

    ERIC Educational Resources Information Center

    Dick, Walter; King, Debby

    1994-01-01

    Reviews the traditional formative evaluation model used by instructional designers; summarizes Kirkpatrick's model of evaluation; proposes the integration of part of Kirkpatrick's model with traditional formative evaluation; and discusses performance-context formative evaluation. (three references) (LRW)

  3. 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 [Zhu?ngyuán 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

  4. Ring Formation in Magnetically Subcritical Clouds and Multiple Star Formation

    E-print Network

    Zhi-Yun Li

    2001-05-02

    We study numerically the ambipolar diffusion-driven evolution of non-rotating, magnetically subcritical, disk-like molecular clouds, assuming axisymmetry. Previous similar studies have concentrated on the formation of single magnetically supercritical cores at the cloud center, which collapse to form isolated stars. We show that, for a cloud with many Jeans masses and a relatively flat mass distribution near the center, a magnetically supercritical ring is produced instead. The supercritical ring contains a mass well above the Jeans limit. It is expected to break up, through both gravitational and possibly magnetic interchange instabilities, into a number of supercritical dense cores, whose dynamic collapse may give rise to a burst of star formation. Non-axisymmetric calculations are needed to follow in detail the expected ring fragmentation into multiple cores and the subsequent core evolution. Implications of our results on multiple star formation in general and the northwestern cluster of protostars in the Serpens molecular cloud core in particular are discussed.

  5. Constraint Lingo: A program for solving logic puzzles and other tabular constraint problems.

    E-print Network

    Truszczynski, Miroslaw

    woman 1 grapefruit ivory kate woman 4 kiwi tahiti liana woman 5 peach belgium martin man 3 lemon quebec tangelo kiwi grapefruit CLASS visits: quebec tahiti haiti martinique belgium ivory These lines declare

  6. 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. PMID:25653834

  7. Cambio climtico y diversidad de la flora vascular en las montaas tabulares de Guayana

    E-print Network

    Vegas Vlarrúbia, Teresa

    Rull Universitat Autònoma de Barcelona. Departament de Biologia Animal, Biologia Vegetal i Ecologia. Departament d'Ecologia. Facultat de Biologia Diagonal 645, 08028 Barcelona. Spain Sandra Nogué Universitat Autònoma de Barcelona. Departament de Biologia Animal, Biologia Vegetal i Ecologia. 08193 Bellaterra

  8. 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

  9. Traditional Chinese Medicine and herbal hepatotoxicity: a tabular compilation of reported cases.

    PubMed

    Teschke, Rolf; Zhang, Li; Long, Hongzhu; Schwarzenboeck, Alexander; Schmidt-Taenzer, Wolfgang; Genthner, Alexander; Wolff, Albrecht; Frenzel, Christian; Schulze, Johannes; Eickhoff, Axel

    2015-01-01

    Traditional Chinese Medicine (TCM) with its focus on herbal use became popular worldwide. Treatment was perceived as safe, with neglect of rare adverse reactions including liver injury. To compile worldwide cases of liver injury by herbal TCM, we undertook a selective literature search in the PubMed database and searched for the items Traditional Chinese Medicine, TCM, Traditional Asian Medicine, and Traditional Oriental Medicine, also combined with the terms herbal hepatotoxicity or herb induced liver injury. The search focused primarily on English-language case reports, case series, and clinical reviews. We identified reported hepatotoxicity cases in 77 relevant publications with 57 different herbs and herbal mixtures of TCM, which were further analyzed for causality by the Council for International Organizations of Medical Sciences (CIOMS) scale, positive reexposure test results, or both. Causality was established for 28/57 different herbs or herbal mixtures, Bai Xian Pi, Bo He, Ci Wu Jia, Chuan Lian Zi, Da Huang, Gan Cao, Ge Gen, Ho Shou Wu, Huang Qin, Hwang Geun Cho, Ji Gu Cao, Ji Xue Cao, Jin Bu Huan, Jue Ming Zi, Jiguja, Kudzu, Ling Yang Qing Fei Keli, Lu Cha, Rhen Shen, Ma Huang, Shou Wu Pian, Shan Chi, Shen Min, Syo Saiko To, Xiao Chai Hu Tang, Yin Chen Hao, Zexie, and Zhen Chu Cao. In conclusion, this compilation of liver injury cases establishes causality for 28/57 different TCM herbs and herbal mixtures, aiding diagnosis for physicians who care for patients with liver disease possibly related to herbal TCM. PMID:25536637

  10. Constraint Lingo: A program for solving logic puzzles and other tabular constraint problems.

    E-print Network

    Truszczynski, Miroslaw

    a speci ed number of rows and columns. The values in the table are subject to constraints, both implicit gender position soda country claude man 6 tangelo haiti jeanne woman 1 grapefruit ivory kate woman 4 kiwi position: 1 .. 6 circular CLASS soda: blueberry lemon peach tangelo kiwi grapefruit CLASS visits: quebec

  11. STAR FORMATION IN ATOMIC GAS

    SciTech Connect

    Krumholz, Mark R., E-mail: krumholz@ucolick.org [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)

    2012-11-01

    Observations of nearby galaxies have firmly established, over a broad range of galactic environments and metallicities, that star formation occurs exclusively in the molecular phase of the interstellar medium (ISM). Theoretical models show that this association results from the correlation between chemical phase, shielding, and temperature. Interstellar gas converts from atomic to molecular only in regions that are well shielded from interstellar ultraviolet (UV) photons, and since UV photons are also the dominant source of interstellar heating, only in these shielded regions does the gas become cold enough to be subject to Jeans instability. However, while the equilibrium temperature and chemical state of interstellar gas are well correlated, the timescale required to reach chemical equilibrium is much longer than that required to reach thermal equilibrium, and both timescales are metallicity-dependent. Here I show that the difference in timescales implies that, at metallicities below a few percent of the solar value, well shielded gas will reach low temperatures and proceed to star formation before the bulk of it is able to convert from atomic to molecular. As a result, at extremely low metallicities, star formation will occur in a cold atomic phase of the ISM rather than a molecular phase. I calculate the observable consequences of this result for star formation in low-metallicity galaxies, and I discuss how some current numerical models for H{sub 2}-regulated star formation may need to be modified.

  12. Review of nutrition labeling formats.

    PubMed

    Geiger, C J; Wyse, B W; Parent, C R; Hansen, R G

    1991-07-01

    This article examines nutrition labeling history as well as the findings of nine research studies of nutrition labeling formats. Nutrition labeling regulations were announced in 1973 and have been periodically amended since then. In response to requests from consumers and health care professionals for revision of the labeling system, the Food and Drug Administration initiated a three-phase plan for reform of nutrition labeling in 1990. President Bush signed the Nutrition Labeling and Education Act in November 1990. Literature analysis revealed that only nine studies with an experimental design have focused on nutrition labeling since 1971. Four were conducted before 1975, which was the year that nutrition labeling was officially implemented, two were conducted in 1980, and three were conducted after 1986. Only two of the nine studies supported the traditional label format mandated by the Code of Federal Regulations, and one study partially supported it. Four of the nine studies that evaluated graphic presentations of nutrition information found that consumer comprehension of nutrition information was improved with a graphic format for nutrition labeling: three studies supported the use of bar graphs and one study supported the use of a pie chart. Full disclosure (ie, complete nutrient and ingredient labeling) was preferred by consumers in two of the three studies that examined this variable. The third study supported three types of information disclosure dependent upon socioeconomic class. In those studies that tested graphics, a bar graph format was significantly preferred and showed better consumer comprehension than the traditional format. PMID:2071796

  13. 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

  14. Deposit formation in hydrocarbon fuels

    NASA Technical Reports Server (NTRS)

    Roback, R.; Szetela, E. J.; Spadaccini, L. J.

    1982-01-01

    The hydrocarbon fuels RP-1, commercial-grade propane, JP-7 and chemically pure propane were subjected to tests in a high pressure fuel coking apparatus in order to evaluate their thermal decomposition limits and carbon deposition rates in heated copper tubes. A fuel thermal stability parametric evaluation was conducted at 136-340 atmospheres, bulk fuel velocities of 6-30 m/sec, and tube wall temperatures of 422-811 K, and the effect of inside wall material on deposit formation was evaluated in tests using nickel-plated tubes. Results show RP-1 deposit formation at wall temperatures between 600 and 800 K, with peak deposit formation near 700 K. Substitution of deoxygenated JP-7 for RP-1 showed no improvement, and the carbon deposition rates for propane fuels were found to be higher than those of either of the kerosene fuels. Nickel plating of the tube walls significantly reduced RP-1 carbon deposition rates.

  15. Biofilm formation by Clostridium difficile

    PubMed Central

    Dapa, Tanja; Unnikrishnan, Meera

    2013-01-01

    Clostridium difficile infection (CDI) is a major healthcare-associated disease worldwide. Recurring infections and increasing antibiotic resistance have complicated treatment of CDI. While C. difficile spores are important for transmission and persistence of CDI, other factors such as gut colonization and formation of bacterial communities in the gut may also contribute to pathogenesis and persistence, but have not been well investigated. Recently, we reported that important clinical C. difficile strains are able to form composite biofilms in vitro. C. difficile biofilm formation is a complex process, modulated by several different factors, including cell surface components and regulators. We also reported that bacteria within biofilms are more resistant to high concentrations of vancomycin, the antibiotic of choice for treatment of CDI. Here we summarize our recent findings and discuss the implications of biofilm formation by this anaerobic gut pathogen in disease pathogenesis and treatment. PMID:23892245

  16. Formation of Coronal Shock Waves

    E-print Network

    Luli?, S; Žic, T; Kienreich, I W; Muhr, N; Temmer, M; Veronig, A M

    2013-01-01

    Numerical simulations of magnetosonic wave formation driven by an expanding cylindrical piston are performed to get better physical insight into the initiation and evolution of large-scale coronal waves. Several very basic initial configurations are employed to analyze intrinsic characteristics of the MHD wave formation that do not depend on specific properties of the environment. It turns out that these simple initial configurations result in piston/wave morphologies and kinematics that reproduce common characteristics of coronal waves. In the initial stage the wave and the expanding source-region cannot be clearly resolved. During the acceleration stage of the source-region inflation, the wave is driven by the piston expansion, so its amplitude and phase-speed increase, whereas the wavefront profile steepens. At a given point, a discontinuity forms in the wavefront profile. The time/distance required for the shock formation is shorter for a more impulsive source-region expansion. After the piston stops, the...

  17. 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 ? cold dark matter (?CDM) 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

  18. Formation of the first stars

    NASA Astrophysics Data System (ADS)

    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 ? cold dark matter (?CDM) 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 ˜106 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.

  19. Cosmic Star-Formation History

    NASA Astrophysics Data System (ADS)

    Madau, Piero; Dickinson, Mark

    2014-08-01

    Over the past two decades, an avalanche of new data from multiwavelength imaging and spectroscopic surveys has revolutionized our view of galaxy formation and evolution. Here we review the range of complementary techniques and theoretical tools that allow astronomers to map the cosmic history of star formation, heavy element production, and reionization of the Universe from the cosmic “dark ages” to the present epoch. A consistent picture is emerging, whereby the star-formation rate density peaked approximately 3.5 Gyr after the Big Bang, at z?1.9, and declined exponentially at later times, with an e-folding timescale of 3.9 Gyr. Half of the stellar mass observed today was formed before a redshift z = 1.3. About 25% formed before the peak of the cosmic star-formation rate density, and another 25% formed after z = 0.7. Less than ˜1% of today's stars formed during the epoch of reionization. Under the assumption of a universal initial mass function, the global stellar mass density inferred at any epoch matches reasonably well the time integral of all the preceding star-formation activity. The comoving rates of star formation and central black hole accretion follow a similar rise and fall, offering evidence for coevolution of black holes and their host galaxies. The rise of the mean metallicity of the Universe to about 0.001 solar by z = 6, one Gyr after the Big Bang, appears to have been accompanied by the production of fewer than ten hydrogen Lyman-continuum photons per baryon, a rather tight budget for cosmological reionization.

  20. Requirements for Hirano Body Formation

    PubMed Central

    Griffin, Paul; Piggott, Cleveland; Maselli, Andrew; Fechheimer, Marcus

    2014-01-01

    Hirano bodies are paracrystalline F-actin-rich structures associated with diverse conditions, including neurodegeneration and aging. Generation of model Hirano bodies using altered forms of Dictyostelium 34-kDa actin-bundling protein allows studies of their physiological function and mechanism of formation. We describe a novel 34-kDa protein mutant, E60K, with a point mutation within the inhibitory domain of the 34-kDa protein. Expression of E60K in Dictyostelium induces the formation of model Hirano bodies. The E60K protein has activated actin binding and is calcium regulated, unlike other forms of the 34-kDa protein that induce Hirano bodies and that have activated actin binding but lack calcium regulation. Actin filaments in the presence of E60K in vitro show enhanced resistance to disassembly induced by latrunculin B. Actin filaments in model Hirano bodies are also protected from latrunculin-induced depolymerization. We used nocodazole and blebbistatin to probe the role of the microtubules and myosin II, respectively, in the formation of model Hirano bodies. In the presence of these inhibitors, model Hirano bodies can form but are smaller than controls at early times of formation. The ultrastructure of model Hirano bodies did not reveal any major difference in structure and organization in the presence of inhibitors. In summary, these results support the conclusion that formation of model Hirano bodies is promoted by gain-of-function actin filament bundling, which enhances actin filament stabilization. Microtubules and myosin II contribute to but are not required for formation of model Hirano bodies. PMID:24632241

  1. Modeling Formation of Globular Clusters: Beacons of Galactic Star Formation

    Microsoft Academic Search

    Oleg Y. Gnedin

    2011-01-01

    Modern hydrodynamic simulations of galaxy formation are able to predict accurately the rates and locations of the assembly of giant molecular clouds in early galaxies. These clouds could host star clusters with the masses and sizes of real globular clusters. I describe current state-of-the-art simulations aimed at understanding the origin of the cluster mass function and metallicity distribution. Metallicity bimodality

  2. Hydrodynamic Simulations of Galaxy Formation

    E-print Network

    A. A. Thoul

    1994-12-09

    We have developed an accurate, one-dimensional, spherically symmetric, Lagrangian hydrodynamics/gravity code, designed to study the effects of radiative cooling and photo-ionization on the formation of protogalaxies. We examine the ability of collapsing perturbations to cool within the age of the universe. In contrast to some studies based on order-of-magnitude estimates, we find that cooling arguments alone cannot explain the sharp upper cutoff observed in the galaxy luminosity function. We also look at the effect of a photoionizing background on the formation of low-mass galaxies.

  3. 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

  4. South Mississippi's Hosston, Sligo formations

    SciTech Connect

    Not Available

    1981-08-24

    The Hosston and Sligo formations, of Early Cretaceous age, lie above the Cotton Valley group and below the Pine Island formation. The beds dip southwesterly and become thicker within the Mississippi Interior Salt basin, where virtually all of the Hosston/Sligo oil and gas production occurs. The 3500 ft of alternating sands and shales found at 10,000-17,000 ft depths have the attributes of fluvial deltaic sediments. The Newsom, Bowie Creek, and Seminary fields are representative of recent gas discoveries in the Hosston/Sligo.

  5. 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.

  6. 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.

  7. RESEARCH STUDY ON NEUTRON INTERACTIONS IN MATTER AS RELATED TO IMAGE FORMATION. Period Covered, October 1, 1961December 31, 1961

    Microsoft Academic Search

    1962-01-01

    Research was carried out to find optimum characteristics (sensitivity ; and resolution) of neutron image detector systems compatible with the image ; quality for various neutron radiographic objects, which may include a significant ; neutron scattering component. The characteristics of the following thermal ; neutron imaging detectors are summarized in tabular form: activation foils with x-; ray films; B¹° and

  8. 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). ...

  9. 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,…

  10. Peptide formation mediated by cyanate

    NASA Technical Reports Server (NTRS)

    Flores, J. J.; Leckie, J. O.

    1973-01-01

    An investigation has been conducted to find out whether peptide formation can be enhanced by cyanate added to hydroxyapatite or orthophosphates. The results show that diglycine is formed when glycine is heated in the presence of apatite or orthophosphates. The addition of inorganic cyanate increases the yields of diglycine but its action as a condensing agent extends only to some of the orthophosphates studied.

  11. The Physics of Star Formation

    E-print Network

    Richard B. Larson

    2003-08-17

    Our current understanding of the physical processes of star formation is reviewed, with emphasis on processes occurring in molecular clouds like those observed nearby. The dense cores of these clouds are predicted to undergo gravitational collapse characterized by the runaway growth of a central density peak that evolves toward a singularity. As long as collapse can occur, rotation and magnetic fields do not change this qualitative behavior. The result is that a very small embryonic star or protostar forms and grows by accretion at a rate that is initially high but declines with time as the surrounding envelope is depleted. Rotation causes some of the remaining matter to form a disk around the protostar, but accretion from protostellar disks is not well understood and may be variable. Most, and possibly all, stars form in binary or multiple systems in which gravitational interactions can play a role in redistributing angular momentum and driving episodes of disk accretion. Variable accretion may account for some peculiarities of young stars such as flareups and jet production, and protostellar interactions in forming systems of stars will also have important implications for planet formation. The most massive stars form in the densest environments by processes that are not yet well understood but may include violent interactions and mergers. The formation of the most massive stars may have similarities to the formation and growth of massive black holes in very dense environments.

  12. Summary: Modes of Star Formation

    E-print Network

    Richard B. Larson

    2001-01-03

    This contribution summarizes briefly the main topics covered at this wide-ranging conference. Much of the evidence presented indicates that star formation occurs in discrete episodes or bursts that produce stellar groupings of all sizes, the fossil remnants of which make up the present stellar populations of galaxies.

  13. Curriculum Vitae Format PERSONAL DATA

    E-print Network

    Niebur, Ernst

    Curriculum Vitae Format Part I PERSONAL DATA Name Office address, phone #, fax #, email Home) Proposal Review Activities External to School of Nursing Internal to School of Nursing Major resources, # of registered students for the past ten years). For clinical teaching, state the course title and size

  14. 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.…

  15. A standard audit trail format

    SciTech Connect

    Bishop, M. [Univ. of California, Davis, CA (United States). Dept. of Computer Science

    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.

  16. Stereotype Formation: Biased by Association

    Microsoft Academic Search

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

    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 information influence the extent to which participants later form

  17. Cloud Formation, Evolution and Destruction

    E-print Network

    Estalella, Robert

    Chapter 4 Cloud Formation, Evolution and Destruction We now begin to trace the journey towards a star. How long does this take? The answer is surprisingly short: a good many clouds already contain new stars and these stars tend to be young. The typical cloud cannot spend long, if any time at all

  18. Earth and Terrestrial Planet Formation

    E-print Network

    Jacobson, Seth A

    2015-01-01

    The growth and composition of Earth is a direct consequence of planet formation throughout the Solar System. We discuss the known history of the Solar System, the proposed stages of growth and how the early stages of planet formation may be dominated by pebble growth processes. Pebbles are small bodies whose strong interactions with the nebula gas lead to remarkable new accretion mechanisms for the formation of planetesimals and the growth of planetary embryos. Many of the popular models for the later stages of planet formation are presented. The classical models with the giant planets on fixed orbits are not consistent with the known history of the Solar System, fail to create a high Earth/Mars mass ratio, and, in many cases, are also internally inconsistent. The successful Grand Tack model creates a small Mars, a wet Earth, a realistic asteroid belt and the mass-orbit structure of the terrestrial planets. In the Grand Tack scenario, growth curves for Earth most closely match a Weibull model. The feeding zon...

  19. Computer simulation of bubble formation

    Microsoft Academic Search

    Z. Insepov; T. Bazhirov; G. Norman; V. Stegailov

    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.

  20. Formation of Clastic Sedimentary Rocks

    NSDL National Science Digital Library

    2010-01-01

    This animation traces the formation of sedimentary rock. It starts at a beach environment where sea water minerals cement sand grains together. The animation concludes with a real microscopic image of sandstone showing both mineral grains and cement. The animation can be paused and rewound to stress important points.

  1. Biofilm formation in Streptococcus pneumoniae

    PubMed Central

    Domenech, Mirian; García, Ernesto; Moscoso, Miriam

    2012-01-01

    Summary Biofilm?grown bacteria are refractory to antimicrobial agents and show an increased capacity to evade the host immune system. In recent years, studies have begun on biofilm formation by Streptococcus pneumoniae, an important human pathogen, using a variety of in vitro model systems. The bacterial cells in these biofilms are held together by an extracellular matrix composed of DNA, proteins and, possibly, polysaccharide(s). Although neither the precise nature of these proteins nor the composition of the putative polysaccharide(s) is clear, it is known that choline?binding proteins are required for successful biofilm formation. Further, many genes appear to be involved, although the role of each appears to vary when biofilms are produced in batch or continuous culture. Prophylactic and therapeutic measures need to be developed to fight S.?pneumoniae biofilm formation. However, much care needs to be taken when choosing strains for such studies because different S.?pneumoniae isolates can show remarkable genomic differences. Multispecies and in vivo biofilm models must also be developed to provide a more complete understanding of biofilm formation and maintenance. PMID:21906265

  2. 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…

  3. 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.

  4. The Story of Galaxy Formation

    E-print Network

    Wechsler, Risa H.

    " Spring #$$% Compton Lectures Edwin Hubble · In the &*#$+s" Hubble was busy studying ,spiral nebulaeThe Story of Galaxy Formation in Our Universe Dr! Risa H! Wechsler Hubble Fellow" Enrico Fermi:((kicp!uchicago!edu()risa(compton( Risa H! Wechsler" Spring #$$% Compton Lectures Hubble Space Telescope #12;Risa H! Wechsler" Spring

  5. Reverse hydrotropy by complex formation.

    PubMed

    Wojciechowski, Kamil; Gutberlet, Thomas; Raghuwanshi, Vikram Singh; Terry, Ann

    2015-01-14

    Self-aggregation of three di-N-alkylated diaza-18-crown-6 ethers (ACEs) was studied in non-polar solvents. The three ACEs differed by the length of the alkyl chain: n-decyl (ACE-10), n-hexadecyl (ACE-16) and n-tetracosane (ACE-24). From the previously reported interfacial tension isotherms, the formation of reverse micelles was expected above ACE concentrations of ?10(-3) M. However, the water content analysis in conjunction with Dynamic Light Scattering (DLS), Fluorescence Correlation Spectroscopy (FCS) and (1)H NMR Diffusion Ordered Spectroscopy (DOSY) do not provide any clear proof of the existence of aggregates. Only the Small Angle Neutron Scattering (SANS) of concentrated toluene ACE solutions reveals the existence of small reverse micelles (probably ACE dimers forming small cages hosting 1-2 water molecules). On the other hand, spectrophotometric and fluorescence dye dissolution studies using eosin Y, tropaeolin OO and methyl orange suggest that ACEs can dissolve these dyes without requiring the formation of aggregates. This discrepancy was interpreted assuming the dye-ACE complexation as the driving force for dye solubilisation, providing a possible mechanism of reverse hydrotropy ("lipotropy") in non-polar solvents. This example shows that special care should be taken when dye solubilisation is used to probe self-aggregation of an amphiphile in non-polar solvents. The amphiphile-dye complex formation might be responsible for false positive results and the aggregate formation should always be confirmed with other methods. PMID:25415596

  6. A Bluetooth scatternet formation algorithm

    Microsoft Academic Search

    Ching Law; Kai-Yeung Siu

    2001-01-01

    A Bluetooth ad hoc network can be formed by interconnecting piconets into scatternets. The constraints and properties of Bluetooth scatternets present special challenges in forming an ad hoc network efficiently. We present and analyse a new randomized distributed algorithm for Bluetooth scatternet formation. We prove that our algorithm achieves O(log n) time complexity and O(n) message complexity. We show that:

  7. Method of fracturing a geological formation

    DOEpatents

    Johnson, James O. (2679-B Walnut, Los Alamos, NM 87544)

    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.

  8. Peripheral Leptin Regulates Bone Formation

    PubMed Central

    Turner, Russell T.; Kalra, Satya P.; Wong, Carmen P.; Philbrick, Kenneth A.; Lindenmaier, Laurence B.; Boghossian, Stephane; Iwaniec, Urszula T.

    2012-01-01

    Substantial evidence does not support the prevailing view that leptin, acting through a hypothalamic relay, decreases bone accrual by inhibiting bone formation. To clarify the mechanisms underlying regulation of bone architecture by leptin, we evaluated bone growth and turnover in wild type (WT) mice, leptin receptor-deficient db/db mice, leptin-deficient ob/ob mice and ob/ob mice treated with leptin. We also performed hypothalamic leptin gene therapy to determine the effect of elevated hypothalamic leptin levels on osteoblasts. Finally, to determine the effects of loss of peripheral leptin signaling on bone formation and energy metabolism, we used bone marrow (BM) from WT or db/db donor mice to reconstitute the hematopoietic and mesenchymal stem cell compartments in lethally irradiated WT recipient mice. Decreases in bone growth, osteoblast-lined bone perimeter and bone formation rate were observed in ob/ob mice and greatly increased in ob/ob mice following subcutaneous administration of leptin. Similarly, hypothalamic leptin gene therapy increased osteoblast-lined bone perimeter in ob/ob mice. In spite of normal osteoclast-lined bone perimeter, db/db mice exhibited a mild but generalized osteopetrotic-like (calcified cartilage encased by bone) skeletal phenotype and greatly reduced serum markers of bone turnover. Tracking studies and histology revealed quantitative replacement of BM cells following BM transplantation. WT mice engrafted with db/db BM did not differ in energy homeostasis from untreated WT mice or WT mice engrafted with WT BM. Bone formation in WT mice engrafted with WT BM did not differ from WT mice, whereas bone formation in WT mice engrafted with db/db cells did not differ from the low rates observed in untreated db/db mice. In summary, our results indicate that leptin, acting primarily through peripheral pathways, increases osteoblast number and activity. PMID:22887758

  9. 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.

  10. 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.

  11. Modeling Formation of Globular Clusters: Beacons of Galactic Star Formation

    Microsoft Academic Search

    Oleg Y. Gnedin

    2010-01-01

    Modern hydrodynamic simulations of galaxy formation are able to predict\\u000aaccurately the rates and locations of the assembly of giant molecular clouds in\\u000aearly galaxies. These clouds could host star clusters with the masses and sizes\\u000aof real globular clusters. I describe current state-of-the-art simulations\\u000aaimed at understanding the origin of the cluster mass function and metallicity\\u000adistribution. Metallicity bimodality

  12. Cusp formation in positron scattering at the positronium formation threshold

    NASA Astrophysics Data System (ADS)

    Sullivan, James; Jones, Adric; Caradonna, Peter; Makochekanwa, Casten; Slaughter, Dan; Buckman, Stephen

    2010-03-01

    The extent to which channel coupling plays a role in positron scattering cross sections has long been debated, and recent work has suggested that a step-like feature in the elastic cross section is due to the rapid rise of the positronium formation cross section from threshold [1]. The low energy, high resolution beamline at the Australin Positron Beamline Facility provides a useful tool with which to study such effects. It provides a means to measure the grand total, positronium formation and elastic scattering cross sections in the region of interest, as well as having the capacity to make measurements of other inelastic scattering processes [2]. This talk will present measurements of positron scattering from noble gas atoms in the region of the positronium formation threshold showing cusp-like features in the elastic scattering channel for each target measured. Comparison with recent work on this phenomenon will be made and discrepancies in the two measurements discussed. [4pt] [1] Coleman et al., Phys. Rev. Lett. 102, (2009) 173201 [0pt] [2] Sullivan et al., Rev. Sci. Instr. 79 (2008) 113105

  13. 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.

  14. Concepts in CMB Anisotropy Formation

    E-print Network

    Wayne Hu

    1995-11-27

    These lecture notes form a primer on the theory of cosmic microwave background (CMB) anisotropy formation. With emphasis on conceptual aspects rather than technical issues, we examine the physical foundations of anisotropy evolution in relativistic kinetic and perturbation theory as well as the manifestation of these principles in primary and secondary anisotropies. We discuss gauge choice and gauge invariance and their use in understanding the CMB. Acoustic, gravitational redshift and ionization effects have robust signatures in the CMB spectrum and may allow determination of classical cosmological parameters as well as reveal general distinctions between models for structure formation. We develop the tight and weak coupling approximations as analytic tools to help understand these effects and the robustness of their signatures.

  15. The dynamics of city formation.

    PubMed

    Henderson, J Vernon; Venables, Anthony J

    2009-04-01

    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

  16. 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.

  17. Laser beam pulse formatting method

    DOEpatents

    Daly, Thomas P. (Livermore, CA); Moses, Edward I. (Livermore, CA); Patterson, Ralph W. (Livermore, CA); Sawicki, Richard H. (Danville, CA)

    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.

  18. Shock formation in Lovelock theories

    NASA Astrophysics Data System (ADS)

    Reall, Harvey S.; Tanahashi, Norihiro; Way, Benson

    2015-02-01

    We argue that Lovelock theories of gravity suffer from shock formation, unlike general relativity. We consider the propagation of (i) a discontinuity in curvature, and (ii) weak, high frequency, gravitational waves. Such disturbances propagate along characteristic hypersurfaces of a "background" spacetime and their amplitude is governed by a transport equation. In general relativity, the transport equation is linear. In Lovelock theories, it is nonlinear and its solutions can blow up, corresponding to the formation of a shock. We show that this effect is absent in some simple cases, e.g. a flat background spacetime, and demonstrate its presence for a plane wave background. We comment on weak cosmic censorship, the evolution of shocks, and the nonlinear stability of Minkowski spacetime, in Lovelock theories.

  19. 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

  20. Magnetic Diffusion in Star Formation

    NASA Astrophysics Data System (ADS)

    Basu, Shantanu; Dapp, Wolf B.

    2011-04-01

    Magnetic diffusion plays a vital role in star formation. We trace its influence from interstellar cloud scales down to star-disk scales. On both scales, we find that magnetic diffusion can be significantly enhanced by the buildup of strong gradients in magnetic field structure. Large scale nonlinear flows can create compressed cloud layers within which ambipolar diffusion occurs rapidly. However, in the flux-freezing limit that may be applicable to photoionized molecular cloud envelopes, supersonic motions can persist for long times if driven by an externally generated magnetic field that corresponds to a subcritical mass-to-flux ratio. In the case of protostellar accretion, rapid magnetic diffusion (through Ohmic dissipation with additional support from ambipolar diffusion) near the protostar causes dramatic magnetic flux loss. By doing so, it also allows the formation of a centrifugal disk, thereby avoiding the magnetic braking catastrophe.

  1. 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.

  2. Seminoe 3, a tidally influenced lowstand wedge and its relationships with subjacent highstand and overlying transgressive deposits, Haystack Mountains Formation, Cretaceous Western Interior, Wyoming (USA)

    NASA Astrophysics Data System (ADS)

    Mellere, Donatella

    1996-06-01

    The Campanian Haystack Mountains Formation (Wyoming, USA) consists of a series of deltaic/estuarine and shoreface sandstone tongues stacked in basinward-stepping units separated by shale intervals. Regional analysis indicates that the tongues have a distinctive two-tiered architecture: (a) a lower sandbody with bioturbated and hummocky strata of wave-dominated shoreface origin; and (b) an erosively based upper unit with bioturbated to tabular cross-bedded sandstones. This study focuses on a single tongue, Seminoe 3, which crops out in a 40 km long continuous dip-oriented exposure. In its landward reaches (westwards) the tongue consists of a thin unit of offshore-transitional to lower shoreface deposits. In the central part of the exposure it becomes thicker and consists of a cross-bedded wedge which truncates the shoreface deposits and pinches out by downlap eastwards onto a thick, westward migrating, shoreface lithosome (spit), probably developed on the margin of a wave-dominated delta. Detailed correlation and mapping of bounding surfaces indicate that the shoreface and spit lithosomes were deposited in a forced regressive mode during falling relative sea-level. The overlying cross-bedded lithosome, is a lowstand wedge which prograded over an incised topography created during the early stage of sea-level lowstand. A large embayment is suggested to have developed during the highstand/forced regressive phase, with shoreline and spit deposits prograding from opposing sides. Significant erosion and truncation occurred during the lowstand phase, as well as a basinward shift of facies onto the shelf and the pre-existing spit deposits. In the early stage of transgression the embayment was drowned, and a tide-dominated, estuarine environment was established. The resulting cross-bedded wedge displays an aggrading to prograding stacking pattern of parasequences with the uppermost portion exhibiting a retrogradational pattern, as a consequence of the reworking operated by the transgression.

  3. Divorce law and family formation

    Microsoft Academic Search

    Scott Drewianka

    2008-01-01

    Several studies have investigated whether unilateral divorce laws raised divorce rates, with mixed results. This paper asks\\u000a whether unilateral, and no-fault, divorce laws influenced family formation. Besides their interest to policy makers, such\\u000a effects may help theorists understand the mechanisms through which laws affect behavior. The results suggest that no-fault\\u000a laws slightly reduced fertility, and unilateral divorce modestly increased divorce

  4. 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.

  5. Equilibrium cluster formation and gelation

    E-print Network

    Rodrigo Sanchez; Paul Bartlett

    2005-06-22

    We study the formation and growth of equilibrium clusters in a suspension of weakly-charged colloidal particles and small non-adsorbing polymers. The effective potential is characterised by a short-range attraction and a long-range repulsion. The size, shape and local structure of the clusters are studied using three-dimensional particle microscopy. We observe a rapid growth in the mean cluster size and the average number of nearest neighbours approaching the gel boundary.

  6. Union formation in fragile families

    Microsoft Academic Search

    Marcia Carlson; Sara Mclanahan; Paula England

    2004-01-01

    In this article, we use data from a new longitudinal survey—the Fragile Families and Child Wellbeing Study—to examine union\\u000a formation among unmarried parents who have just had a child together. We used multinomial logistic regression to estimate\\u000a the effects of economic, cultural\\/interpersonal, and other factors on whether (relative to having no romantic relationship)\\u000a parents are romantically involved and living apart,

  7. Kinetic models of opinion formation

    E-print Network

    G. Toscani

    2006-05-17

    We introduce and discuss certain kinetic models of (continuous) opinion formation involving both exchange of opinion between individual agents and diffusion of information. We show conditions which ensure that the kinetic model reaches non trivial stationary states in case of lack of diffusion in correspondence of some opinion point. Analytical results are then obtained by considering a suitable asymptotic limit of the model yielding a Fokker-Planck equation for the distribution of opinion among individuals.

  8. Formation processes of framboidal pyrite

    Microsoft Academic Search

    R. T. Wilkin; H. L. Barnes

    1997-01-01

    Pyrite framboid formation may be the result of four consecutive processes: (1) nucleation and growth of initial iron monosulfide microcrystals; (2) reaction of the microcrystals to greigite (Fe3S4; (3) aggregation of uniformly sized greigite microcrystals, i.e., framboid growth; and (4) replacement of greigite framboids by pyrite. The uniform morphology, uniform size range, and ordering of the microcrystals in individual framboids,

  9. Hydrodynamics of catheter biofilm formation

    E-print Network

    Sotolongo-Costa, Oscar; Rodriguez-Perez, Daniel; Martinez-Escobar, Sergio; Fernandez-Barbero, Antonio

    2009-01-01

    A hydrodynamic model is proposed to describe one of the most critical problems in intensive medical care units: the formation of biofilms inside central venous catheters. The incorporation of approximate solutions for the flow-limited diffusion equation leads to the conclusion that biofilms grow on the internal catheter wall due to the counter-stream diffusion of blood through a very thin layer close to the wall. This biological deposition is the first necessary step for the subsequent bacteria colonization.

  10. Supershells and propagating star formation

    NASA Technical Reports Server (NTRS)

    Mccray, Richard; Kafatos, Minas

    1987-01-01

    Stellar winds and repeated supernovae from an OB association will create a cavity of coronal gas in the interstellar medium, with radius greater than 100 pc, surrounded by a dense, expanding shell of cool interstellar gas. If the association has a typical initial mass function, its supernovae explosions will inject energy into the supershell at a nearly constant rate for about 50 Myr. The supershell loses its interior pressure and enters the snowplow phase when radiative cooling becomes important or when the shell bursts through the gas disk of a galaxy, typically after a few times 10 Myr and with a radius of 100-300 pc. At approximately the same time, the supershell becomes gravitationally unstable, forming giant molecular clouds which are sites for new star formation. There is widespread evidence for supershells in the Galaxy and other spiral and irregular galaxies from 21-cm emission-line surveys, optical emission-line surveys, and studies of supernova remnants. The gravitational instability of the supershells provides a physical mechanism for induced star formation and may account for bursts of star formation, especially in irregular galaxies.

  11. The Formation of Star Clusters

    E-print Network

    Bradley C. Whitmore

    2000-12-29

    The ability of HST to resolve objects ten times smaller than possible from the ground has rejuvenated the study of young star clusters. A recurrent morphological theme found in nearby resolved sytems is the observation of young (typically 1 - 10 Myr), massive (10**3 - 10**4 M_sun), compact (rho ~ 10**5 M_sun/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 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 (10**3 - 10**7 M_sun), 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.

  12. 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.

  13. 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.

  14. Star formation in HI debris

    NASA Astrophysics Data System (ADS)

    Oliveira, Claudia

    We propose to use GALEX observations to search for evidence of star formation in the intergalatic HI clouds of nearby galaxy systems. The method, identifying starburst sources (the so called intergalactic HII regions) coincident with HI clouds, has been recently used to demonstrate significant star formation outside of galaxies in Stephan's quintet. Mendes de Oliveira et al. 2004, (see also http://www.gemini.edu/project/announcements/press/2004-7.html) found several candidates of such star-forming regions using multi-slit spectroscopy which were confirmed by the GALEX pre-release observations of this spectacular interacting group. For this proposal we chose eight nearby systems (z < 3200 km/s), most of which are interacting or merging, which contain intergalactic HI clouds. They were selected from the HI Rogues Gallery of HI maps of galaxies and groups (http://www.nrao.edu/astrores/HIrogues/). Our main goal is to measure or set limits on the UV flux for the intergalactic HII regions that may be present in intergalactic HI clouds, in order to determine their ages and masses. Finding widespread, young, star-forming regions in the eight HI intergalactic clouds, indicating `in situ' formation of these objects, will be strong evidence that this is an efficient mechanism for producing and mixing metals in the intergalactic medium. This may have been even more important in the early universe, when galaxy-galaxy interactions were more frequent and tidal debris more common.

  15. Rock Cycle: Environments of Formation

    NSDL National Science Digital Library

    National Science Teachers Association (NSTA)

    2006-11-01

    This Science Object is the second of four Science Objects in the Rocks SciPack. It provides an in-depth exploration of the conditions and environment required during the formation of igneous, sedimentary, and metamorphic rocks. Igneous rock forms from the cooling and crystallization of magma. Sometimes the magma reaches Earth's surface and cools quickly; sometimes it does not reach the surface and thus cools slowly. Rocks at Earth's surface are subjected to processes of weathering and erosion, producing sediments as they are broken down. Sedimentary rock is formed when sediments are buried and solidified through various processes. Sedimentary rock buried deep enough may be transformed into metamorphic rock or melted down to magma. Rock formed deep within the crust (either igneous or metamorphic) may be forced up again to become land surface and even mountains by the forces that drive the motion of Earth's plates. Subsequently, this new rock too will erode. Learning Outcomes:? Realize that different rocks have specific origins, and that they are the product of any number of processes.? Identify the processes through which igneous, sedimentary, and metamorphic rock form.? Explain the role of intermediary materials such as sediment and magma in the formation of different kinds of rock.? Provide an overarching description of the steps in the rock cycle, the formation of sedimentary rock, the re-forming of rock by heat and pressure, and the process by which re-formed rock can return to the surface.

  16. Galaxies within hierarchical structure formation

    NASA Astrophysics Data System (ADS)

    Munoz, Joseph Antonio

    2010-12-01

    While the structure of the Universe can typically be studied only by observing the light from luminous galaxies, the distribution of the galaxies themselves is ultimately a product of the formation of the dark matter halos that host them. This thesis explores the relationship between galaxies and the hierarchical growth of the cosmic web. Employing analytic and numerical techniques, we investigate the effects of the structure formation on observations of galaxies and use galaxy observations to constrain the underlying theoretical models. On large scales, the Lagrangian-based excursion-set formalism calculates the statistics of halos in a given survey volume, with any Eulerian evolution away from the Hubble flow described by the spherical collapse model. However, we also rely on high-resolution N-body simulations of dark matter to treat the nonlinear behavior on small-scales. We consider how the clustering of massive halos and the rapid evolution of their abundance with redshift informs the interpretation of high-redshift galaxy surveys with the Hubble Space Telescope. We further calculate the density and dynamics of the Shapley Supercluster from X-ray observations of galaxy clusters, primarily from the ROSAT satellite, and place constraints on reionization and the formation of first stars using Sloan Digital Sky Survey data from relics of the early Universe orbiting the Milky Way.

  17. Absorption and elimination of formate following oral administration of calcium formate in female human subjects

    E-print Network

    Hanzlik, Robert P.; Fowler, S. C.; Eells, Janis T.

    2005-02-01

    Published abstract: Calcium formate is a water-soluble salt of an essential mineral nutrient with potential for use as a dietary calcium supplement. Formate ion is a product of endogenous and xenobiotic metabolism, but sustained high plasma formate...

  18. Basin scale evolution of formation waters: a diagenetic and formation water study of the Triassic Chaunoy Formation, Paris Basin

    Microsoft Academic Search

    R. H Worden; M. L Coleman; J-M Matray

    1999-01-01

    Formation waters and their movements within basins are commonly attributed with responsibility for patterns of cementation and porosity-loss within reservoirs and aquifers. It is thus important to understand when and how waters move in the subsurface. We have studied the evolution and movement of formation water in the Triassic Chaunoy Formation of the Paris Basin, NW Europe to define the

  19. Formation damage in underbalanced drilling operations

    E-print Network

    Reyes Serpa, Carlos Alberto

    2003-01-01

    Formation damage has long been recognized as a potential source of reduced productivity and injectivity in both horizontal and vertical wells. From the moment that the pay zone is being drilled until the well is put on production, a formation...

  20. Gas-Phase Infrared; JCAMP Format

    National Institute of Standards and Technology Data Gateway

    SRD 35 NIST/EPA Gas-Phase Infrared; JCAMP Format (PC database for purchase)   This data collection contains 5,228 infrared spectra in the JCAMP-DX (Joint Committee for Atomic and Molecular Physical Data "Data Exchange") format.

  1. 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.

  2. NCI Best Case Summary Format-OCCAM

    Cancer.gov

    The following is a sample Case Report Format used to submit BCS Case Summaries Please adhere to the suggestions below. You may alter the format but include as much of the indicated content as possible.

  3. External Resource: The Formation of the Moon

    NSDL National Science Digital Library

    1900-01-01

    This Windows to The Universe webpage explores the formation of the Moon. Topics: Moon surface, planetismals, Period of Late Heavy Bombardment, Moon core and mantle, lunar Maria, collisional ejection theory, capture theory, co-formation theory.

  4. Dynamics and control of electromagnetic satellite formations

    E-print Network

    Ahsun, Umair, 1972-

    2007-01-01

    Satellite formation flying is an enabling technology for many space missions, especially for space-based telescopes. Usually there is a tight formation-keeping requirement that may need constant expenditure of fuel or at ...

  5. 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.

  6. Formation of the terrestrial planets from planetesimals

    NASA Technical Reports Server (NTRS)

    Wetherill, George W.

    1991-01-01

    Formation of the terrestrial planets from planetesimals is discussed. The following subject areas are covered: (1) formation of the original planetesimals; (2) growth of planetesimals into planetary embryos; and (3) growth of runaway planetary embryos into terrestrial planets.

  7. FORMATIONS EN ODONTOLOGIE POUR LES CHIRURGIENS DENTISTES

    E-print Network

    Brest, Université de

    FORMATIONS EN ODONTOLOGIE POUR LES CHIRURGIENS DENTISTES OBJECTIFS DES FORMATIONS Les journées de, néphrologie, cancérologie,...) et chirurgiens dentistes (28 mars 2013) la prise en charge de nos patients pour

  8. Negative ion formation processes: A general review

    SciTech Connect

    Alton, G.D.

    1990-01-01

    The principal negative ion formation processes will be briefly reviewed. Primary emphasis will be placed on the more efficient and universal processes of charge transfer and secondary ion formation through non-thermodynamic surface ionization. 86 refs., 20 figs.

  9. 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.

  10. Statistical physics and opinion formation

    NASA Astrophysics Data System (ADS)

    Shao, Jia

    Many complex systems can be described by networks in which the nodes are the elements of the system and the links characterize the interactions between the elements. There have been concerted efforts to understand the topological properties of model and real-life complex networks. We solve analytically the structure of shells in a randomly connected complex network. Further, we study an opinion formation model based on complex networks and show that the process of opinion formation can be mapped to a real-life physics process---invasion percolation. We define shell ? in a network as the set of nodes at distance ? with respect to a given node and define r? as the fraction of nodes outside shell ?. We derive analytically the degree distribution and average degree of the nodes residing outside shell ? as a function of r?. Further, we find that r? follows an iterative functional form r ? = ?(r?-1), where ? is expressed in terms of the generating function of the original degree distribution of the network. For real world networks the theoretical prediction of r? deviates from the empirical r?. We introduce a network correlation function c(r?) ? r ?/?(r?-1) to characterize the correlations in the networks. We find that the networks fall into two distinct classes: (i) a class of poorly-connected networks with c(r?) > 1; (ii) a class of well-connected networks with c(r ?) < 1. We also apply the concept of a percolation phase transition to the modeling of opinion formation in complex networks. We propose a "non-consensus" opinion model that allows for stable coexistence of two opinions. We find that the model displays phase transition behavior characterized by a large spanning cluster of nodes holding the same opinion appearing when the concentration of nodes holding the same opinion rises above a certain threshold. Our simulations support the hypothesis that the non-consensus opinion model appears to belong to the same universality class as invasion percolation.

  11. Sequential star formation in Cassiopeia

    NASA Astrophysics Data System (ADS)

    Velasco, S.; García, M.; Negueruela, I.

    2013-05-01

    Massive stars (M ? 9 M_{?}) are usually formed in OB associations, consisting of one or more not very massive open clusters and a halo of scattered young stars. The study of these open clusters can provide clues about how stellar formation proceeds from the parent molecular clouds. We present first results on a project to understand sequential star formation mechanisms in OB associations. We have chosen associations Cas OB4, Cas OB5 and Cas OB7, close to the Cassiopeia constellation, at l = 110°-125°. Previous determinations of their distance provided very similar values for them all, and placed them on the Perseus Arm. This study aims at improved distance and age determinations using new spectroscopic observations and existing photometry. The goal is to investigate whether the clusters in Cas OB4, Cas OB5 and Cas OB7 are separate entities or can be enclosed in a global common OB association. If associated,we will check for evidence of induced star formation. We preselected about 100 stars from 12 clusters, based on photometric criteria. Long-slit spectra were taken with the Intermediate Dispersion Spectrograph at the Isaac Newton Telescope (2.5 m), located in La Palma's Observatorio del Roque de los Muchachos. We used the R632V grating, to achieve a spectral coverage between 3500 Å and 5500 Å and spectral resolution of 0.90 Å px^{-1}. The observed spectra have been used to determine the spectral type and luminosity class of the sample stars. The spectral classification yields the stellar properties (from calibrations), and will enable the reconstruction of the HR-diagram. We present in this poster newly discovered B-type stars in two selected clusters.

  12. Electrochemical formation of field emitters

    DOEpatents

    Bernhardt, Anthony F. (Berkeley, CA)

    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.

  13. 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.

  14. Percolation-induced frost formation

    NASA Astrophysics Data System (ADS)

    Guadarrama-Cetina, J.; Mongruel, A.; González-Viñas, W.; Beysens, D.

    2013-01-01

    We report the observation of an unconventional mechanism for frost formation. On a smooth hydrophobic surface cooled much below the water freezing temperature (-9 °C), we find that, instead of the classical freezing of individual supercooled condensed droplets, frost can occur through a multi-step 2-dimensional percolation-driven mechanism. This in-plane propagation process provides a model to investigate more complex bulk phase transformations such as those occurring in atmospheric supercooled clouds. It can also lead to a new method to control and design in-plane solidification at a nanoscale level.

  15. Dust formation by failed supernovae

    NASA Astrophysics Data System (ADS)

    Kochanek, C. S.

    2014-11-01

    We consider dust formation during the ejection of the hydrogen envelope of a red supergiant during a failed supernova (SN) creating a black hole. While the dense, slow moving ejecta are very efficient at forming dust, only the very last phases of the predicted visual transient will be obscured. The net grain production consists of Md ˜ 10- 2 M? of very large grains (10-1000 ?m). This means that failed SNe could be the source of the very large extrasolar dust grains possibly identified by Ulysses, Galileo and radar studies of meteoroid re-entry trails rather than their coming from an ejection process associated with protoplanetary or other discs.

  16. The formation of terrestrial planets

    NASA Astrophysics Data System (ADS)

    Morbidelli, A.; O'Brien, D.

    Previous numerical simulations of the process of formation of the terrestrial planets led to results which typically have two problems: (i) the final orbits of the planets are too eccentric and inclined relative to the real orbits of the terrestrial planet system and (ii) the planets form too slowly with respect to the time indicated by the Hf-W chronometer for the Earth-Moon system. It is usually thought that these problems are due to the fact that the simulations do not account for a population of small planetesimals carrying cumulatively a mass comparable to the mass of the planetary embryos. We have done new simulations, starting with a system of 25 Mars-mass embryos initially distributed from 0.5 to 4 AU, embedded in a disk of 2.5 Earth masses of planetesimals, modeled with 1,000 individual equal-mass particles. We have performed 8 simulations. 4 simulations assumed Jupiter and Saturn initially on their current orbits, while the remaining 4 simulations assumed that the two giant planets had circular orbits, consistent with the `Nice model' on the origin of the late heavy bombardment (Gomes et al., 2005) and on the giant planets' orbital architecture (Tsiganis et al., 2005). The simulations starting with Jupiter on an eccentric orbit lead to the formation of a system of terrestrial planets whose angular momentum deficit is 7 times smaller than that obtained in previous simulations (Chambers, 2001), whereas the formation timescale is three times shorter. This confirms that the dynamical friction exerted by planetesimals onto the forming planets is an essential ingredient in terrestrial planet formation. Interestingly, the final terrestrial planets achieved in these simulations are dynamically colder than the real terrestrial planets. The simulations starting with Jupiter on a circular orbit still produce planets which are slightly too dynamically excited (by about 50%) and which form too slowly (by a factor of 2). These problems are expected to disappear in future simulations modeling the planetesimal disk with a larger number of particles, or accounting for the regeneration of planetesimals during giant collisions among embryos. A main difference between the planets formed in the eccentric Jupiter case with respect to the circular Jupiter case is that the former do not acquire a significant amount of mass from beyond 2.5 AU. These planets are therefore expected to be more deficient in water, possibly too dry with respect to the Earth.

  17. Zonal flow as pattern formation

    SciTech Connect

    Parker, Jeffrey B.; Krommes, John A. [Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)] [Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)

    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.

  18. Transcriptional control of adipocyte formation

    PubMed Central

    Farmer, Stephen R.

    2007-01-01

    A detailed understanding of the processes governing adipose tissue formation will be instrumental in combating the obesity epidemic. Much progress has been made in the last two decades in defining transcriptional events controlling the differentiation of mesenchymal stem cells into adipocytes. A complex network of transcription factors and cell-cycle regulators, in concert with specific transcriptional coactivators and corepressors, respond to extracellular stimuli to activate or repress adipocyte differentiation. This review summarizes advances in this field, which constitute a framework for potential antiobesity strategies. PMID:17011499

  19. Bidirectional translator between DXF and IGES formats

    Microsoft Academic Search

    1990-01-01

    Software was conceived that provided two-way CAD data exchange between AuotCAD's DXF format and the IGES format. Obstacles were found with a newly emerging DXF format, and enhancements were added to accommodate multiple DXF forms. Successful code was written using the C programming language, thus providing portability to other hardware. Future enhancements to the code were identified. 4 refs.

  20. The formation of protoplasts from Beauveria bassiana

    Microsoft Academic Search

    Tom A. Pfeifer; George G. Khachatourians

    1987-01-01

    Beauveria bassiana protoplast formation from blastospores, conidia and mycelia was studied. The method of protoplast formation involves preincubation of the fungal cells with dithiothreitol and subsequent treatment with an enzyme mixture consisting of: cellulase, chitinase, ß-glucuronidase and lysozyme. Using this procedure protoplasts were formed from blastospores and mycelia but not conidia. Formation of protoplasts from 24 hour old mycelia was

  1. Electromagnetic Formation Flight of Satellite Arrays

    E-print Network

    Electromagnetic Formation Flight of Satellite Arrays Daniel W. Kwon and David W. Miller February 2005 SSL # 2-05 #12;#12;Electromagnetic Formation Flight of Satellite Arrays By DANIEL W. KWON S;#12;Electromagnetic Formation Flight of Satellite Arrays by DANIEL W. KWON Submitted to the Department of Aeronautics

  2. Control of star formation by supersonic turbulence

    Microsoft Academic Search

    Mordecai-Mark Mac Low; Ralf S. Klessen

    2004-01-01

    Understanding the formation of stars in galaxies is central to much of modern astrophysics. However, a quantitative prediction of the star formation rate and the initial distribution of stellar masses remains elusive. For several decades it has been thought that the star formation process is primarily controlled by the interplay between gravity and magnetostatic support, modulated by neutral-ion drift (known

  3. 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…

  4. 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.…

  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. Different strategies for midline formation in bilaterians

    Microsoft Academic Search

    Hans Meinhardt

    2004-01-01

    The evolutionary emergence of the bilateral body plan and the central nervous system required the establishment of a midline organizer. The formation of a solitary, elongated but narrow organizing region for the dorsoventral (or mediolateral) axis requires rather complex molecular interactions. Different modes of midline formation evolved in vertebrates, insects and planarians, indicating that midline formation had a crucial role

  7. 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…

  8. Formation control of weak autonomous robots

    Microsoft Academic Search

    Huan Zhang; Pubudu N. Pathirana

    2011-01-01

    Formation of autonomous mobile robots to an arbitrary geometric pattern in a distributed fashion is a fundamental problem in formation control. This paper presents a new fully distributed, memoryless (oblivious) algorithm to the formation control problem via distributed optimization techniques. The optimization minimizes an appropriately defined difference function between the current robot distribution and target geometric pattern. The optimization processes

  9. 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.

  10. Improving Foreign Language Speaking through Formative Assessment

    ERIC Educational Resources Information Center

    Tuttle, Harry Grover; Tuttle, Alan Robert

    2012-01-01

    Want a quick way to get your students happily conversing more in the target language? This practical book shows you how to use formative assessments to gain immediate and lasting improvement in your students' fluency. You'll learn how to: (1) Imbed the 3-minute formative assessment into every lesson with ease; (2) Engage students in peer formative

  11. Kinetics of Film Formation by Interfacial Polycondensation

    E-print Network

    Freger, Viatcheslav "Slava"

    Kinetics of Film Formation by Interfacial Polycondensation Viatcheslav Freger* Zuckerberg Institute An approximate analytical model of film formation by interfacial polycondensation is presented. The analysis (insipient film formation, slowdown, and diffusion-limited growth) sets a different pattern of local polymer

  12. 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 very compact). In tabular form, the relation is shown between this classification and a morphologically disturbed appearance for the galaxy.

  13. Trust Assets of Financial Institutions 1996: Federal Deposit Insurance Corporation (FDIC)

    NSDL National Science Digital Library

    1996-01-01

    The US Federal Deposit Insurance Corporation has released this report, a series of 47 tables (ASCII format only) in five major categories (personal and employee benefit trust activities, collective investment funds, corporate trust activities, affiliated investment advisors, and fiduciary income.)

  14. 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

  15. Autonomous Formation Flight: Project Overview

    NASA Technical Reports Server (NTRS)

    Cole, Jennifer; Cobleigh, Brent; Vachon, Jake; Ray, Ronald J.; Ennix, Kimberly; Walsh, Kevin

    2008-01-01

    Objectives: a) Map the vortex effects; b) Formation Auto-Pilot Requirements. Two NASA F/A-18 aircraft in formation: a) NASA 845 Systems Research Aircraft; b) NASA 847 Support Aircraft. Flight Conditions: M = 0.56, 25000 feet (Subsonic condition); b) M = 0.86, 36000 feet (Transonic condition). Nose-To-Tail (N2T) Distances: 20, 55, 110 and 190 feet. Lessons learned: a) Controllable flight in vortex is possible with pilot feedback (displays); b) Position hold at best C(sub D), is attainable; c) Best drag location is close to max rolling moment; e) Drag reductions demonstrated up to 22% (WFE up to 20%); f) Induced drag results compare favorably with simple prediction model; g) "Sweet Spot" (lateral & vertical area > 25%) is larger than predicted; h) Larger wing overlaps result in sign reversals in roll, yaw; i) As predicted, favorable effects degrade gradually with increased nose-to-tail distances after peaking at 3 span lengths aft; and j) Demonstrated - over 100 N mi (>15%) range improvement and 650 lbs (14%) fuel savings on actual simulated F/A-18 cruise mission.

  16. Globular Cluster Formation in Mergers

    E-print Network

    Francois Schweizer

    2006-06-01

    Mergers of gas-rich galaxies lead to gravitationally driven increases in gas pressure that can trigger intense bursts of star and cluster formation. Although star formation itself is clustered, most newborn stellar aggregates are unbound associations and disperse. Gravitationally bound star clusters that survive for at least 10-20 internal crossing times (~20-40 Myr) are relatively rare and seem to contain globular clusters formed in present-day mergers exceed omega Cen by an order of magnitude in mass, yet appear to have normal stellar initial mass functions. In the local universe, recent remnants of major gas-rich disk mergers appear as protoelliptical galaxies with subpopulations of typically 100-1000 young metal-rich globular clusters in their halos. The evidence is now strong that these "second-generation" globular clusters formed from giant molecular clouds in the merging disks, squeezed into collapse by large-scale shocks and high gas pressure rather than by high-velocity cloud-cloud collisions. Similarly, first- generation metal-poor globular clusters may have formed during cosmological reionization from low-metallicity giant molecular clouds squeezed by the universal reionization pressure.

  17. 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.

  18. 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.

  19. Bar Formation from Galaxy Flybys

    NASA Astrophysics Data System (ADS)

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

    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.

  20. Montezuma Formation of Costa Rica

    SciTech Connect

    McKee, W.H.; Sen Gupta, B.K.

    1985-01-01

    The Montezuma Formation of the Nicoya Peninsula is one of the better known Neogene stratigraphic units of the Pacific side of Costa Rica. Past workers have reported its age to be Miocene-Pliocene or Miocene-Quaternary, and its environment of deposition to be inner shelf. The planktonic foraminiferal record of the unit in the type locality, however, places it firmly in the Lower Pliocene (Globorotalia margaritae zones). Furthermore, benthic such as Bolivina interjuncta var. bicostata, Epistominella exigua, and E. pacifica indicate that the sedimentation occurred at depths no shallower than the outermost shelf. No drastic faunal turnovers are observed within the formation; a cluster analysis of various Neogene samples from the Nicoya Peninsula and other Pacific areas of Costa Rica demonstrate an overall uniformity of the Montezuma fauna. The frequency trends of certain species, particularly of Epistominella exigua, however, suggest a transgression, the assemblage in the upper part of the section definitely representing upper bathyal depths. Judging by the present elevation of Montezuma outcrops, this part of Costa Rica has been uplifted at least 300 meters in the past 5 m.y.

  1. Virialization Heating in Galaxy Formation

    SciTech Connect

    Wang, P. (KIPAC, Menlo Park); Abel, T. (Santa Barbara, KITP)

    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.

  2. The Formation of Globular Cluster Systems

    E-print Network

    Patrick Cote

    2002-10-26

    I briefly review models for the formation of globular cluster systems, and summarize the observational properties (i.e., formation efficiencies, metallicity distributions, kinematics and ages) of the globular cluster systems of M87 and M49: two thoroughly studied elliptical galaxies. Many of the properties of the metal-poor clusters in these and other galaxies appear to be consistent with their formation in low-mass, proto-galactic fragments, as proposed by several different formation models. A number of outstanding questions concerning the formation of the metal-rich clusters in these galaxies are highlighted.

  3. A formulation of stability for spacecraft formations

    NASA Technical Reports Server (NTRS)

    Acikmese, Ahmet Behcet; Hadaegh, Fred Y.; Scharf, Daniel P.; Ploen, Scott R.

    2005-01-01

    A formulation of stability for a set of spacecraft in formation flight is presented. First, a formation is defined in a precise mathematical form in terms of control interactions. Then, stability is formulated based on input-to-output stability with respect to a partitioning of the formation dynamics. This formulation of stability is shown to be useful in characterizing disturbance propagation in the formation as a function of the partition interconnection topology, and also in analyzing the robustness of sensing, communication, and control topologies. Stability results are presented for hierarchical, cyclic, and disturbance attenuating formations.

  4. Heating tar sands formations while controlling pressure

    DOEpatents

    Stegemeier, George Leo (Houston, TX) [Houston, TX; Beer, Gary Lee (Houston, TX) [Houston, TX; Zhang, Etuan (Houston, TX) [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.

  5. Data Formats for SAR Archival and Distribution

    NASA Astrophysics Data System (ADS)

    Cunningham, K.

    2010-12-01

    Synthetic Aperture Radar (SAR) data has historically been archived and distributed in the Committee on Earth Observation Satellite (CEOS) format. CEOS has some limitations, so future SAR missions are considering using the Hierarchical Data Format (HDF) format that is more compatible with other sensors supporting the Earth Observing System (EOS). With the adoption of HDF for SAR archival, the distribution formats of SAR data products are also under consideration. As SAR becomes more important in EOS, data formats compatible with geographic information systems (GIS) are needed and the GeoTIFF image format for the distribution of SAR data is the preferred choice. By moving into a more common data format, SAR data products may appeal to a larger audience. This paper summarizes the collaboration of the Alaska Satellite Facility, the National Snow and Ice Data Center, and the Oak Ridge National Laboratory to support the growing use of SAR for terrestrial ecology, resource management, and many other applications.

  6. Iberulites and meteorological formation conditions

    NASA Astrophysics Data System (ADS)

    Díaz-Hernández, Jose Luis

    2010-05-01

    It has recently been established that iberulites are heterogeneous, complex components of the atmosphere, coexisting with other particulate matter that establishes genetic relations with them in the context of the troposphere in the vicinity of the Sahara Desert. Unlike the other particulate matter, the appearance of iberulites is a discrete phenomenon. The main period for iberulite collection is in the summer, characterised in the southern Iberian Peninsula by high temperatures and considerable decrease in precipitation. Iberulites have been obtained in this season under two main meteorological conditions: fair weather and wet deposition ("red rain" conditions). Both conditions can have in common the occasional presence of masses of air loaded with aerosols from the Sahara. Fair weather conditions are more favourable for iberulites formation. They occur in the central, hottest times of the summer. In this context iberulites have been collected under two conditions: clear days only interrupted by daytime cumulus clouds and hazy days with reduced visibility. In both cases a mixture of iberulites and aerosols was obtained. Wet deposition conditions are mainly found during the overlapping periods between spring-summer and summer-autumn (May-June and September-October), when there is a higher risk of precipitation than in summer. "Red rains" (or muddy rains) occur when these precipitations are superposed on Sahara dust plumes and they often contain iberulites among their components. The proportion of water to solid load in these precipitations is very variable, but the character of red rain can be lost with a very high proportion of water and iberulite formation can even pass unnoticed as they disintegrate. In this case, only impacts of very varied sizes and shapes water droplets loaded with aerosols would be visible, with no apparent sign of iberulites. If the proportion is more balanced, we observe impacts of droplets that vary considerably in size and solid charge, together with well-formed iberulites. In this case, all types of gradations of droplet-iberulites are visible, as well as all the final stages of iberulite evolution. Outside the periods mentioned above, the influence of the North Atlantic Oscillation (NAO) on the southern Iberian region is stronger, with the westerly and north-westerly winds providing less aerosols and more rain, cleaning the atmosphere and thus preventing the formation of iberulites.

  7. Formation of Coronal Shock Waves

    NASA Astrophysics Data System (ADS)

    Luli?, S.; Vršnak, B.; Žic, T.; Kienreich, I. W.; Muhr, N.; Temmer, M.; Veronig, A. M.

    2013-09-01

    Magnetosonic wave formation driven by an expanding cylindrical piston is numerically simulated to obtain better physical insight into the initiation and evolution of large-scale coronal waves caused by coronal eruptions. Several very basic initial configurations are employed to analyze intrinsic characteristics of MHD wave formation that do not depend on specific properties of the environment. It turns out that these simple initial configurations result in piston/wave morphologies and kinematics that reproduce common characteristics of coronal waves. In the initial stage, the wave and the expanding source region cannot be clearly resolved; i.e. a certain time is needed before the wave detaches from the piston. Thereafter, it continues to travel as what is called a "simple wave." During the acceleration stage of the source region inflation, the wave is driven by the piston expansion, so its amplitude and phase-speed increase, whereas the wavefront profile steepens. At a given point, a discontinuity forms in the wavefront profile; i.e. the leading edge of the wave becomes shocked. The time/distance required for the shock formation is shorter for a more impulsive source-region expansion. After the piston stops, the wave amplitude and phase speed start to decrease. During the expansion, most of the source region becomes strongly rarefied, which reproduces the coronal dimming left behind the eruption. However, the density increases at the source-region boundary, and stays enhanced even after the expansion stops, which might explain stationary brightenings that are sometimes observed at the edges of the erupted coronal structure. Also, in the rear of the wave a weak density depletion develops, trailing the wave, which is sometimes observed as weak transient coronal dimming. Finally, we find a well-defined relationship between the impulsiveness of the source-region expansion and the wave amplitude and phase speed. The results for the cylindrical piston are also compared with the outcome for a planar wave that is formed by a one-dimensional piston, to find out how different geometries affect the evolution of the wave.

  8. A physiological study of formate dehydrogenase, formate oxidase and hydrogenlyase from Escherichia coli K-12

    Microsoft Academic Search

    J. Ruiz-Herrera; A. Alvarez

    1972-01-01

    Escherichia coli was grown under various culture conditions. Variations in the levels of formate dehydrogenase which reacts with methylene\\u000a blue (MB) or phenazine methosulfate (PMS) (N enzyme), formate dehydrogenase which reacts with benzyl viologen (BV) (H enzyme),\\u000a formate oxidase and hydrogenlyase were analyzed. It was observed that formate dehydrogenase N and formate oxidase were induced\\u000a by nitrate and repressed by

  9. Adaptive Optics in Star Formation

    E-print Network

    Wolfgang Brandner

    2003-09-29

    Over the past ten years, the concept of adaptive optics has evolved from early experimental stages to a standard observing tool now available at almost all major optical and near-infrared telescope facilities. Adaptive optics will also be essential in exploiting the full potential of the large optical/infrared interferometers currently under construction. Both observations with high-angular resolution and at high contrast, and with a high point source sensitivity are facilitated by adaptive optics. Among the areas which benefit most from the use of adaptive optics are studies of the circumstellar environment (envelopes, disks, outflows), substellar companions and multiple systems, and dense young stellar populations. This contribution highlights some of the recent advances in star formation studies facilitated by adaptive optics, and gives a brief tutorial on optimized observing and data reduction strategies.

  10. 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.

  11. 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.

  12. Experimental studies of spheromak formation

    SciTech Connect

    Bruhns, H.; Chin-Fatt, C.; Chong, Y.P.; DeSilva, A.W.; Goldenbaum, G.C.; Griem, H.R.; Hart, G.W.; Hess, R.A.; Irby, J.H.; Shaw, R.S.

    1983-06-01

    Studies in the PS-1 spheromak configuration can be effectively formed by a combined z- and theta-pinch technique on both a fast (tau/sub formation/approx. =tau/sub Alfve/n) and a much slower timescale. The gross tilt and shift instability of the toroid can be suppressed by a combination of conduction walls, shaping the separatrix by externally applied fields, and the use of ''figure-eight'' coils. Optimum stabilty is obtained for almost spherical toroids. Maximum field-reversal times for stable, well-confined toroids are > or =40 /..mu..sec, consistent with resistive decay. Temperatures during the stable decay are 5--10 eV; impurity radiation is an important energy-loss mechanism.

  13. Sandpile formation by revolving rivers

    E-print Network

    E. Altshuler; O. Ramos; A. J. Batista-Leyva; A. Rivera; K. E. Bassler

    2002-06-25

    Experimental observation of a new mechanism of sandpile formation is reported. As a steady stream of dry sand is poured onto a horizontal surface, a pile forms which has a thin river of sand on one side flowing from the apex of the pile to the edge of its base. The river rotates about the pile, depositing a new layer of sand with each revolution, thereby growing the pile. For small piles the river is steady and the pile formed is smooth. For larger piles, the river becomes intermittent and the surface of the pile becomes undulating. The frequency of revolution of the river is measured as the pile grows and the results are explained with a simple scaling argument. The essential features of the system that produce the phenomena are discussed.

  14. Formation of zirconium metallic glass.

    PubMed

    Zhang, Jianzhong; Zhao, Yusheng

    2004-07-15

    Bulk metallic glasses are commonly produced by the rapid cooling of liquid alloys. They have emerged over the past decade as a novel class of materials, with attractive properties and technological promise. The bulk metallic glasses so far produced contain three or more component elements. These complex compositions are necessary to frustrate the crystallization of the liquid melt on cooling, but can also lead to phase separation, which is detrimental to the thermal and mechanical properties of metallic glasses. Here we report, using X-ray diffraction measurements, the formation of a bulk metallic glass from elemental zirconium at high static pressures and low temperatures (relative to its melting temperature at atmospheric pressure). Amorphous zirconium can be recovered at ambient conditions and demonstrates a superior thermal stability compared to amorphous alloys, which could lead to new high-temperature applications of amorphous metals. PMID:15254533

  15. 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.

  16. 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.

  17. 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.

  18. Cataract formation following vitreoretinal procedures

    PubMed Central

    Feng, Hao; Adelman, Ron A

    2014-01-01

    Purpose To evaluate the incidence and prevalence of cataract formation, progression, and extraction in patients that underwent vitreoretinal procedures and to evaluate factors that can potentially predispose patients to postoperative cataracts. Materials and methods The medical records of consecutive patients who underwent vitreoretinal surgery at the Yale Eye Center with at least 6 months of follow-up and no prior intraocular surgery were obtained. Preoperative, intraoperative, and postoperative data were recorded and analyzed in this retrospective observational study. The main outcome measures were defined as cataract extraction, formation, and progression after vitreoretinal procedures. The lens status of the surgical eye was recorded preoperatively and at 1 month, 3 months, 6 months, 12 months, 24 months, and 36 months postoperatively. Results A total of 193 eyes of 180 patients fulfilled the inclusion criteria. The percentages of eyes with mild lens change were 96% after 20-gauge pars plana vitrectomy (PPV), 72% after small gauge (23- and 25-gauge) PPV, 38% after scleral buckle (SB), 38% after pneumatic retinopexy (PR), and 91% after PPV plus SB (PPV+SB). Posterior subcapsular and nuclear sclerotic cataracts were the most common with almost all developing within 24 months. There was no statistically significant difference (P=1.00) between the rate of cataract extraction after 20-gauge (41%) and small gauge PPV (42%), but there was a statistically significant difference between PPV and non-PPV (SB, 6%; PR, 7%; P<0.001) and PPV and PPV+SB groups (69%; P=0.0063). Conclusion Cataracts were common following PPV regardless of the gauge. SB and PR led to the lowest while PPV+SB led to the highest risk of postoperative cataracts. PMID:25284982

  19. Methanol Masers and Star Formation

    E-print Network

    A. M. Sobolev; A. B. Ostrovskii; M. S. Kirsanova; O. V. Shelemei; M. A. Voronkov; A. V. Malyshev

    2006-01-12

    Methanol masers which are traditionally divided into two classes provide possibility to study important parts of the star forming regions: Class~II masers trace vicinities of the massive YSOs while class~I masers are likely to trace more distant parts of the outflows where newer stars can form. There are many methanol transitions which produce observed masers. This allows to use pumping analysis for estimation of the physical parameters in the maser formation regions and its environment, for the study of their evolution. Extensive surveys in different masing transitions allow to conclude on the values of the temperatures, densities, dust properties, etc. in the bulk of masing regions. Variability of the brightest masers is monitored during several years. In some cases it is probably caused by the changes of the dust temperature which follow variations in the brightness of the central YSO reflecting the character of the accretion process. A unified catalogue of the class II methanol masers consisting of more than 500 objects is compiled. Analysis of the data shows that: physical conditions within the usual maser source vary considerably; maser brightness is determined by parameters of some distinguished part of the object - maser formation region; class II methanol masers are formed not within the outflows but in the regions affected by their propagation. It is shown that the "near" solutions for the kinematic distances to the sources can be used for statistical analysis. The luminosity function of the 6.7 GHz methanol masers is constructed. It is shown that improvement of the sensitivity of surveys can increase number of detected maser sources considerably.

  20. 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 psychiatry. PMID:24904262

  1. 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.

  2. Polyphase Strain Caps Formation Mechanism

    NASA Astrophysics Data System (ADS)

    Abu-Alam, Tamer; Stüwe, Kurt

    2010-05-01

    Strain caps are one of a series of microstructures that typically form during deformation of a softer matrix around hard objects. As such, they bear information about the kinematics around these bodies in rocks. However strain caps are barely described outside their original definition. Here we describe these microstructures that feature a new phase - not elsewhere present in the paragenesis - in the strain cap region. This feature is rare but not unique: Examples from Alaska, Sinai and Bhutan all show chlorite strain caps formed around porphyroblasts in foliated mica schists of variable metamorphic grades. Porphyroblasts may be variably muscovite, staurolite or garnet, respectively. In all of these examples strain caps formed initially dynamically during deformation but the new phase grew statically at a later stage. At least three mechanisms that can explain the formation of new phases in the strain cap region: (a) the strain cap region may have experienced different P-T conditions from the matrix during the peak metamorphism; (b) the strain cap region has different effective bulk composition from the surrounding matrix; (c) fluid flow that is preferentially focused parallel to the foliation planes causing only local adjustment to retrograde metamorphism in the strain cap region. A combination between petrography, mineral chemistry and thermodynamic modeling shows that the third hypothesis is the most preferable mechanism that can explain the formation of strain cap minerals. Indeed, the absence of chlorite outside the strain cap region allows a quantification of the amount of fluid that infiltrated the foliation. Keywords: Strain cap, Fluid channelling, Effective bulk composition, Thermodynamic modelling

  3. 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.

  4. Molybdenum and tungsten-dependent formate dehydrogenases.

    PubMed

    Maia, Luisa B; Moura, José J G; Moura, Isabel

    2015-03-01

    The prokaryotic formate metabolism is considerably diversified. Prokaryotes use formate in the C1 metabolism, but also evolved to exploit the low reduction potential of formate to derive energy, by coupling its oxidation to the reduction of numerous electron acceptors. To fulfil these varied physiological roles, different types of formate dehydrogenase (FDH) enzymes have evolved to catalyse the reversible 2-electron oxidation of formate to carbon dioxide. This review will highlight our present knowledge about the diverse physiological roles of FDH in prokaryotes, their modular structural organisation and active site structures and the mechanistic strategies followed to accomplish the formate oxidation. In addition, the ability of FDH to catalyse the reverse reaction of carbon dioxide reduction, a potentially relevant reaction for carbon dioxide sequestration, will also be addressed. PMID:25476858

  5. Autonomous Formations of Multi-Agent Systems

    NASA Technical Reports Server (NTRS)

    Dhali, Sanjana; Joshi, Suresh M.

    2013-01-01

    Autonomous formation control of multi-agent dynamic systems has a number of applications that include ground-based and aerial robots and satellite formations. For air vehicles, formation flight ("flocking") has the potential to significantly increase airspace utilization as well as fuel efficiency. This presentation addresses two main problems in multi-agent formations: optimal role assignment to minimize the total cost (e.g., combined distance traveled by all agents); and maintaining formation geometry during flock motion. The Kuhn-Munkres ("Hungarian") algorithm is used for optimal assignment, and consensus-based leader-follower type control architecture is used to maintain formation shape despite the leader s independent movements. The methods are demonstrated by animated simulations.

  6. Empirical correlation verifies true formation skin

    SciTech Connect

    Kutasov, I.M. [MultiSpectrum Technologies, Santa Monica, CA (United States)

    1995-04-03

    To determine formation (true) skin and the rate-dependent skin, a semi-theoretical equation is proposed for relating the critical value of flow rate (q{sub c}) to formation permeability, formation porosity, and gas/oil dynamic viscosity. An accurate evaluation of skin is important for designing remedial treatments or evaluating gas well productivity. Three examples illustrate the proposed equation. In all cases, the actual gas/oil flow rates are compared with the calculated critical flow rate.

  7. Floating insulated conductors for heating subsurface formations

    DOEpatents

    Burns, David; Goodwin, Charles R.

    2014-07-29

    A heating system for a subsurface formation includes a conduit located in a first opening in the subsurface formation. Three electrical conductors are located in the conduit. A return conductor is located inside the conduit. The return conductor is electrically coupled to the ends of the electrical conductors distal from the surface of the formation. Insulation is located inside the conduit. The insulation electrically insulates the three electrical conductors, the return conductor, and the conduit from each other.

  8. Soot Formation in Combustion Processes (Review)

    Microsoft Academic Search

    Z. A. Mansurov

    2005-01-01

    A review is given of recent papers on the phenomenology, kinetics, and mechanism of soot formation in hydrocarbon combustion;\\u000a the effects of various factors on the formation of polycyclic aromatic hydrocarbons, fullerenes, and soot, low-temperature\\u000a soot formation in cool flames, combustion in electric field, and the paramagnetism of soot particles from an ecological viewpoint\\u000a are considered.

  9. Formation Control of Multiple Biomimetic Robotic Fish

    Microsoft Academic Search

    Jinyan Shao; Junzhi Yu; Long Wang

    2006-01-01

    This paper presents a new method for formation control of multiple underwater fish-like robots. Considering both geometrical and mechanical constrains of the fish-like robots and based on the leader-following approach, a curvature coordinate is introduced to describe relative positions between different members within formations. Both the static and dynamic formations are concerned. We conduct simulations and physical experiments to verify

  10. Processes and problems in secondary star formation

    SciTech Connect

    Klein, R.I.; Whitaker, R.W.; Sandford M.T. II

    1984-03-01

    Recent developments relating the conditions in molecular clouds to star formation triggered by a prior stellar generation are reviewed. Primary processes are those that lead to the formation of a first stellar generation. The secondary processes that produce stars in response to effects caused by existing stars are compared and evaluated in terms of the observational data presently available. We discuss the role of turbulence to produce clumpy cloud structures and introduce new work on colliding inter-cloud gas flows leading to non-linear inhomogeneous cloud structures in an intially smooth cloud. This clumpy morphology has important consequences for secondary formation. The triggering processes of supernovae, stellar winds, and H II regions are discussed with emphasis on the consequences for radiation driven implosion as a promising secondary star formation mechanism. Detailed two-dimensional, radiation-hydrodynamic calculations of radiation driven implosion are discussed. This mechanism is shown to be highly efficient in synchronizing the formation of new stars in congruent to 1-3 x 10/sup 4/ years and could account for the recent evidence for new massive star formation in several UCHII regions. It is concluded that, while no single theory adequately explains the variety of star formation observed, a uniform description of star formation is likely to involve several secondary processes. Advances in the theory of star formation will require multiple dimensional calculations of coupled processes. The important non-linear interactions include hydrodynamics, radiation transport, and magnetic fields.

  11. Heating tar sands formations to visbreaking temperatures

    DOEpatents

    Karanikas, John Michael (Houston, TX); Colmenares, Tulio Rafael (Houston, TX); Zhang, Etuan (Houston, TX); Marino, Marian (Houston, TX); Roes, Augustinus Wilhelmus Maria (Houston, TX); Ryan, Robert Charles (Houston, TX); Beer, Gary Lee (Houston, TX); Dombrowski, Robert James (Houston, TX); Jaiswal, Namit (Houston, TX)

    2009-12-22

    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. The heat may be controlled so that at least a majority of the section reaches an average temperature of between 200.degree. C. and 240.degree. C., which results in visbreaking of at least some hydrocarbons in the section. At least some visbroken hydrocarbon fluids may be produced from the formation.

  12. GLOBULAR CLUSTER FORMATION WITHIN A COSMOLOGICAL CONTEXT

    SciTech Connect

    Boley, Aaron C.; Lake, George; Read, Justin; Teyssier, Romain, E-mail: aaron.boley@gmail.co [Institute for Theoretical Physics, University of Zurich, Winterthurerstrasse 190, Zurich, CH-8057 (Switzerland)

    2009-11-20

    We place constraints on the formation redshifts for blue globular clusters (BGCs), independent of the details of hydrodynamics and population III star formation. The observed radial distribution of BGCs in the Milky Way Galaxy suggests that they formed in biased dark matter halos at high redshift. As a result, simulations of a approx1 Mpc box up to z approx 10 must resolve BGC formation in LAMBDACDM. We find that most halo stars could be produced from destroyed BGCs and other low-mass clusters that formed at high redshift. We present a proof-of-concept simulation that captures the formation of globular-like star clusters.

  13. Hydraulic fracturing of a shallow subsurface formation

    SciTech Connect

    Uhri, D.C.

    1987-12-22

    A method for propagating a vertical hydraulic fracture in an earth formation surrounding a borehole where the original in-situ stresses favor a horizontal fracture is described comprising the steps of: (a) firstly supplying fracturing fluid to the formation at a first depth within the borehole to propagate a horizontal fracture favored by the original in-situ stresses of the formation, and (b) secondly supplying fracturing fluid to the formation at a second depth within the borehole, while maintaining pressure in the horizontal fracture, to propagate a vertical fracture as favored by the in-situ stresses as altered by the propagating of the horizontal fracture.

  14. Sequential hydraulic fracturing of a subsurface formation

    SciTech Connect

    Vogt, T.C. Jr.; Hale, M.W.; Sellers, J.R.

    1989-09-26

    This patent describes a method for propagating a vertical hydraulic fracture in an earth formation surrounding a borehole wherein the original in-situ stresses favor a horizontal fracture. It comprises: pumping a first fracturing fluid into the formation at a first depth within the borehole so that a first fracturing pressure is applied to the formation by the first fracturing fluid to propagate a horizontal fracture as favored by the original in-situ stresses of the formation. The propagation of the horizontal fracture altering the original in-situ stresses in the formation; injecting a propping material into the horizontal fracture while maintaining the first fracturing pressure in the horizontal fracture in sufficient amount to prevent relaxation of the altered in-situ stresses in the formation after the pumping of the first fracturing fluid is terminated and the first fracturing pressure is removed; terminating the pumping of the first fracturing fluid into the horizontal fracture to remove the first fracturing pressure from the formation, pumping a second fracturing into the formation at a second depth within the borehole within the field of the altered in-situ stresses,; and terminating the pumping of the second fracturing fluid to the vertical fracture to remove the second fracturing pressure from the formation.

  15. On the Formation of Brown Dwarfs

    E-print Network

    Ing-Guey Jiang; G. Laughlin; D. N. C. Lin

    2003-09-19

    The observational properties of brown dwarfs pose challenges to the theory of star formation. Because their mass is much smaller than the typical Jeans mass of interstellar clouds, brown dwarfs are most likely formed through secondary fragmentation processes, rather than through the direct collapse of a molecular cloud core. In order to prevent substantial post-formation mass accretion, young brown dwarfs must leave the high density formation regions in which they form. We propose here that brown dwarfs are formed in the circumbinary disks. Through post-formation dynamical interaction with their host binary stars, young brown dwarfs are either scattered to large distance or removed, with modest speed, from their cradles.

  16. Heating systems for heating subsurface formations

    DOEpatents

    Nguyen, Scott Vinh (Houston, TX); Vinegar, Harold J. (Bellaire, TX)

    2011-04-26

    Methods and systems for heating a subsurface formation are described herein. A heating system for a subsurface formation includes a sealed conduit positioned in an opening in the formation and a heat source. The sealed conduit includes a heat transfer fluid. The heat source provides heat to a portion of the sealed conduit to change phase of the heat transfer fluid from a liquid to a vapor. The vapor in the sealed conduit rises in the sealed conduit, condenses to transfer heat to the formation and returns to the conduit portion as a liquid.

  17. Shock formation within sonoluminescence bubbles

    SciTech Connect

    Vuong, V.Q. [University of California, Irvine, Department of Mechanical and Aerospace Engineering, Irvine, California 92697-3975 (United States)] [University of California, Irvine, Department of Mechanical and Aerospace Engineering, Irvine, California 92697-3975 (United States); Szeri, A.J. [University of California at Berkeley, Department of Mechanical Engineering, Berkeley, California 94720-1740 (United States)] [University of California at Berkeley, Department of Mechanical Engineering, Berkeley, California 94720-1740 (United States); Young, D.A. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)] [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

    1999-01-01

    A strong case has been made by several authors that sharp, spherically symmetric shocks converging on the center of a spherical bubble driven by a strong acoustic field give rise to rapid compression and heating that produces the brief flash of light known as sonoluminescence. The formation of such shocks is considered. It is found that, although at the main collapse the bubble wall does indeed launch an inwardly-traveling compression wave, and although the subsequent reflection of the wave at the bubble center produces a very rapid temperature peak, the wave is prevented from steepening into a sharp shock by an adverse gradient in the sound speed caused by heat transfer. It is shown that the mathematical characteristics of the flow can be prevented from accumulating into a shock front by this adverse sound speed gradient. A range of results is presented for a variety of bubble ambient radii and sound field amplitudes suggested by experiments. The time scale of the peak temperature in the bubble is set by the dynamics of the compression wave: this is typically in the range 100{endash}300 ps (FWHM) in concert with recent measurements of the sonoluminescence pulse width. {copyright} {ital 1999 American Institute of Physics.}

  18. Formation of the solar system

    NSDL National Science Digital Library

    Lensyl Urbano

    This exercise is designed as a lab, but can also be used as a classroom demonstration. It requires the use of the VPython programs which require Python and VPython to be installed on your computers (this software is free and has been made available on the default image for all computers on our campus). The models show the gravitational collapse of a set of particles to create a central "Sun" with other orbiting particles, a simple model to demonstrate elliptical orbits, a simple model of the solar system showing the planetary orbits (speeded up). The task is to assess one hypothesis about the formation of the solar system (from a dust and gas nebula) by comparing the computer simulation (model 1) to the shape and form of the actual solar system (model 3). Students can interact with the 3d models by, for example, selecting planetary objects to track, and changing perspectives in 3d space. In doing this students learn about the shapes of the planetary orbits (ellipticity etc) and reasons that they change.

  19. STAR FORMATION IN DENSE CLUSTERS

    SciTech Connect

    Myers, Philip C., E-mail: pmyers@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2011-12-10

    A model of core-clump accretion with equally likely stopping describes star formation in the dense parts of clusters, where models of isolated collapsing cores may not apply. Each core accretes at a constant rate onto its protostar, while the surrounding clump gas accretes as a power of protostar mass. Short accretion flows resemble Shu accretion and make low-mass stars. Long flows resemble reduced Bondi accretion and make massive stars. Accretion stops due to environmental processes of dynamical ejection, gravitational competition, and gas dispersal by stellar feedback, independent of initial core structure. The model matches the field star initial mass function (IMF) from 0.01 to more than 10 solar masses. The core accretion rate and the mean accretion duration set the peak of the IMF, independent of the local Jeans mass. Massive protostars require the longest accretion durations, up to 0.5 Myr. The maximum protostar luminosity in a cluster indicates the mass and age of its oldest protostar. The distribution of protostar luminosities matches those in active star-forming regions if protostars have a constant birthrate but not if their births are coeval. For constant birthrate, the ratio of young stellar objects to protostars indicates the star-forming age of a cluster, typically {approx}1 Myr. The protostar accretion luminosity is typically less than its steady spherical value by a factor of {approx}2, consistent with models of episodic disk accretion.

  20. Spheromak formation studies in SSPX

    SciTech Connect

    Hill, D N; Bulmer, R H; Cohen, B L; Hooper, E B; LoDestro, L L; Mattor, N; McLean, H S; Moller, J; Pearlstein, L D; Ryutov, D D; Stallard, B W; Wood, R D; Woodruff, S; Holcomb, C T; Jarboe, T; Sovinec, C R; Wang, Z; Wurden, G

    2000-09-29

    We present results from the Sustained Spheromak Physics Experiment (SSPX) at LLNL, which has been built to study energy confinement in spheromak plasmas sustained for up to 2 ms by coaxial DC helicity injection. Peak toroidal currents as high as 600kA have been obtained in the 1m dia. (0.23m minor radius) device using injection currents between 200-400kA; these currents generate edge poloidal fields in the range of 0.2-0.4T. The internal field and current profiles are inferred from edge field measurements using the CORSICA code. Density and impurity control is obtained using baking, glow discharge cleansing, and titanium gettering, after which long plasma decay times ({tau} {ge} 1.5ms) are observed and impurity radiation losses are reduced from {approx}50% to <20% of the input energy. Thomson scattering measurements show peaked electron temperature and pressure profiles with T{sub e} (0){approx}120eV and {beta}{sub e}{approx}7%. Edge field measurements show the presence of n=1 modes during the formation phase, as has been observed in other spheromaks. This mode dies away during sustainment and decay so that edge fluctuation levels as low as 1% have been measured. These results are compared with numerical simulations using the NIMROD code.

  1. Cosmic vacuum and galaxy formation

    NASA Astrophysics Data System (ADS)

    Chernin, A. D.

    2006-04-01

    It is demonstrated that the protogalactic perturbations must enter the nonlinear regime before the red shift z? 1; otherwise they would be destroyed by the antigravity of the vacuum dark energy at the subsequent epoch of the vacuum domination. At the zrrV={M/[(8?/3)?V]}1/3, where M is the mass of a given over-density and ?V is the vacuum density. The criterion provides a new relation between the largest mass condensations and their spatial scales. All the real large-scale systems follow this relation definitely. It is also shown that a simple formula is possible for the key quantity in the theory of galaxy formation, namely the initial amplitude of the perturbation of the gravitational potential in the protogalactic structures. The amplitude is time independent and given in terms of the Friedmann integrals, which are genuine physical characteristics of the cosmic energies. The results suggest that there is a strong correspondence between the global design of the Universe as a whole and the cosmic structures of various masses and spatial scales.

  2. Mechanisms of amyloid fibril formation.

    PubMed

    Dovidchenko, N V; Leonova, E I; Galzitskaya, O V

    2014-12-01

    Amyloid and amyloid-like aggregates are elongated unbranched fibrils consisting of ?-structures of separate monomers positioned perpendicular to the fibril axis and stacked strictly above each other. In their physicochemical properties, amyloid fibrils are reminiscent of synthetic polymers rather than usual proteins because they are stable to the action of denaturing agents and proteases. Their mechanical stability can be compared to a spider's web, that in spite of its ability to stretch, is stronger than steel. It is not surprising that a large number of diseases are accompanied with amyloid fibril depositing in different organs. Pathologies provoked by depositing of incorrectly folded proteins include Alzheimer's, Parkinson's, and Huntington's diseases. In addition, this group of diseases involves mucoviscidosis, some types of diabetes, and hereditary cataracts. Each type of amyloidosis is characterized by aggregation of a certain type of protein that is soluble in general, and thus leads to specific distortions of functions of the corresponding organs. Therefore, it is important to understand the process of transformation of "native" proteins to amyloid fibrils to clarify how these molecules acquire such strength and what key elements of this process determine the pathway of erroneous protein folding. This review presents our analysis of complied information on the mechanisms of formation and biochemical properties of amyloid fibrils. PMID:25749162

  3. Pattern formation by shock processes

    SciTech Connect

    Shaner, J.W.

    1983-01-01

    Shock waves in condensed media often produce and leave behind periodic patterns and textures. These patterns have been observed both in real time and in postmortem examination. In many cases the patterns can be related to analogous Pattern-forming mechanisms in classical fluid dynamics, such as the Rayleigh-Taylor and Helmholtz instabilities. In other cases, the textures arise from peculiarities in the dynamic stress state immediately behind the leading edge of the shock wave. Periodic waves in the interface between two shock welded metals have a close resemblance to the classical Helmholtz instability. From a practical point of view, these waves are crucial to the formation of a good bond. Impulsive acceleration of an interface can result in the Meshkov instability, which forms patterns qualitatively similar to the Rayleigh-Taylor instability driven by continuous acceleration. However, the patterned stress state left behind after a shock crosses a perturbed interface can result in perturbation growth for shock propagation in either direction across the interface. Even in homogeneous media, the non-hydrostatic component of the stress behind a shock can drive a pattern forming instability. Adiabatic shear banding has been proposed as a mechanism to explain both the patterns observed in shock-compressed and recovered metal samples and the apparent loss of macroscopic shear strength of shocked ceramics. New optical photographs of shocked quartz support this mechanism. 27 references.

  4. Dune formation under bimodal winds

    PubMed Central

    Parteli, Eric J. R.; Durán, Orencio; Tsoar, Haim; Schwämmle, Veit; Herrmann, Hans J.

    2009-01-01

    The study of dune morphology represents a valuable tool in the investigation of planetary wind systems—the primary factor controlling the dune shape is the wind directionality. However, our understanding of dune formation is still limited to the simplest situation of unidirectional winds: There is no model that solves the equations of sand transport under the most common situation of seasonally varying wind directions. Here we present the calculation of sand transport under bimodal winds using a dune model that is extended to account for more than one wind direction. Our calculations show that dunes align longitudinally to the resultant wind trend if the angle ?w between the wind directions is larger than 90°. Under high sand availability, linear seif dunes are obtained, the intriguing meandering shape of which is found to be controlled by the dune height and by the time the wind lasts at each one of the two wind directions. Unusual dune shapes including the “wedge dunes” observed on Mars appear within a wide spectrum of bimodal dune morphologies under low sand availability. PMID:20018703

  5. Pattern Formation and Complexity Emergence

    NASA Astrophysics Data System (ADS)

    Berezin, Alexander A.

    2001-03-01

    Success of nonlinear modelling of pattern formation and self-organization encourages speculations on informational and number theoretical foundations of complexity emergence. Pythagorean "unreasonable effectiveness of integers" in natural processes is perhaps extrapolatable even to universal emergence "out-of-nothing" (Leibniz, Wheeler). Because rational numbers (R = M/N) are everywhere dense on real axis, any digital string (hence any "book" from "Library of Babel" of J.L.Borges) is "recorded" infinitely many times in arbitrary many rationals. Furthermore, within any arbitrary small interval there are infinitely many Rs for which (either or both) integers (Ms and Ns) "carry" any given string of any given length. Because any iterational process (such as generation of fractal features of Mandelbrot Set) is arbitrary closely approximatable with rational numbers, the infinite pattern of integers expresses itself in generation of complexity of the world, as well as in emergence of the world itself. This "tunnelling" from Platonic World ("Platonia" of J.Barbour) to a real (physical) world is modern recast of Leibniz's motto ("for deriving all from nothing there suffices a single principle").

  6. Collagen fibril formation during development

    SciTech Connect

    Fleischmajer, R.; Perlish, J.S.; Timpl, R.; Olsen, B.R.

    1987-05-01

    Studies with embryonic skin and bone suggested that the aminopropeptide (AP) and carboxylpropeptide (CP) of type I pro-callagen (pro-col) play a role in fibril formation. Chick leg metatarsal tendons were studied by electron microscopy. AP and CP of type I pro-col were purified from chick leg tendons; antibodies developed in rabbits and purity tested by radioimmunoassays. Antibodies were used for immunofluorescence microscopy (IFM) and immunoblotting (IB). The peritendineum, consisting of thin 20-30 nm fibrils, revealed the AP of type I and type III procol. In the tendon area, collagen fibrils were arranged within small compartments and were of uniform diameter at 10d, 14d and 18d. However, beyond 21d, there was confluency of the compartments and a wide range of fibril diameters. IFM revealed fine streaks of collagen, staining with the AP of type I throughout the tendon. The CP was mainly intracellular with only a small amount present in the extracellular space. IB revealed procollagen, pN-collagen (AP+collagen) and pC-collagen, (CP+collagen) at all stages of development. Ratios of pN/pC collagen, determined by spectrophotometric scanning of autoradiographs, correlated well with the distribution of fibril diameter. This study suggests the hypothesis that AP initiates fibrillogenesis while CP may regulate additional fibril growth.

  7. Basin scale evolution of formation waters: a diagenetic and formation water study of the Triassic Chaunoy Formation, Paris Basin

    NASA Astrophysics Data System (ADS)

    Worden, R. H.; Coleman, M. L.; Matray, J.-M.

    1999-10-01

    Formation waters and their movements within basins are commonly attributed with responsibility for patterns of cementation and porosity-loss within reservoirs and aquifers. It is thus important to understand when and how waters move in the subsurface. We have studied the evolution and movement of formation water in the Triassic Chaunoy Formation of the Paris Basin, NW Europe to define the way in which the water has evolved and to interpret water movement patterns using mineral isotope and fluid inclusion data in conjunction with detailed formation water analyses. The Chaunoy Formation is cemented with different types of dolomite, calcite and quartz cement. We have studied the evolution of waters in terms of oxygen, carbon and strontium isotopes and salinity. Connate waters were meteoric in origin but strongly influenced by the proximity of a playa lake. Input of palaeo-meteoric water, which entered the Chaunoy via eastern halite bodies, resulted in highly saline formation water for the majority of the Chaunoy Formation from about 100 Ma until (and for some time after) maximum burial. Saline waters spread into the aquifer initially taking a west-north west trajectory and then switching to a west-south west pattern in the Eocene. Following the Alpine orogeny and localised uplift of the basin margin, the southern portion of Chaunoy received fresh, low salinity, meteoric water. It is likely that formation water was lost from the Chaunoy in a more central part of the basin, via sub-vertical cross formational flow to the Mid Jurassic Dogger Formation, to accommodate the influx of fresh water.

  8. Thermodynamics of ?-amyloid fibril formation

    NASA Astrophysics Data System (ADS)

    Tiana, G.; Simona, F.; Broglia, R. A.; Colombo, G.

    2004-05-01

    Amyloid fibers are aggregates of proteins. They are built out of a peptide called ?-amyloid (A?) containing between 41 and 43 residues, produced by the action of an enzyme which cleaves a much larger protein known as the amyloid precursor protein (APP). X-ray diffraction experiments have shown that these fibrils are rich in ?-structures, whereas the shape of the peptide displays an ?-helix structure within the APP in its biologically active conformation. A realistic model of fibril formation is developed based on the 17 residues A?12-28 amyloid peptide, which has been shown to form fibrils structurally similar to those of the whole A? peptide. With the help of physical arguments and in keeping with experimental findings, the A?12-28 monomer is assumed to be in four possible states (i.e., native helix conformation, ?-hairpin, globular low-energy state, and unfolded state). Making use of these monomeric states, oligomers (dimers, tertramers, and octamers) were constructed. With the help of short, detailed molecular dynamics calculations of the three monomers and of a variety of oligomers, energies for these structures were obtained. Making use of these results within the framework of a simple yet realistic model to describe the entropic terms associated with the variety of amyloid conformations, a phase diagram can be calculated of the whole many-body system, leading to a thermodynamical picture in overall agreement with the experimental findings. In particular, the existence of micellar metastable states seem to be a key issue to determine the thermodynamical properties of the system.

  9. STAR FORMATION IN 30 DORADUS

    SciTech Connect

    De Marchi, Guido; Spezzi, Loredana; Sirianni, Marco; Andersen, Morten [European Space Agency, Space Science Department, Keplerlaan 1, 2200 AG Noordwijk (Netherlands); Paresce, Francesco [Istituto di Astrofisica Spaziale e Fisica Cosmica, Via Gobetti 101, 40129 Bologna (Italy); Panagia, Nino; Mutchler, Max; Whitmore, Bradley C.; Bond, Howard [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Beccari, Giacomo [European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching (Germany); Balick, Bruce [Department of Astronomy, University of Washington, Seattle, WA 98195-1580 (United States); Dopita, Michael A. [Mount Stromlo and Siding Spring Observatories, Research School of Astronomy and Astrophysics, Australian National University, Cotter Road, Weston Creek, ACT 2611 (Australia); Frogel, Jay A. [Galaxies Unlimited, 8726 Hickory Bend Trail, Potomac, MD 20854 (United States); Calzetti, Daniela [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Marcella Carollo, C. [Department of Physics, ETH-Zurich, Zurich 8093 (Switzerland); Disney, Michael J. [School of Physics and Astronomy, Cardiff University, Cardiff CF24 3AA (United Kingdom); Hall, Donald N. B. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Holtzman, Jon A. [Department of Astronomy, New Mexico State University, Las Cruces, NM 88003 (United States); Kimble, Randy A. [NASA-Goddard Space Flight Center, Greenbelt, MD 20771 (United States); McCarthy, Patrick J., E-mail: gdemarchi@rssd.esa.int [Observatories of the Carnegie Institution of Washington, Pasadena, CA 91101-1292 (United States)

    2011-09-20

    Using observations obtained with the Wide-Field Camera 3 on board the Hubble Space Telescope, we have studied the properties of the stellar populations in the central regions of 30 Dor in the Large Magellanic Cloud. The observations clearly reveal the presence of considerable differential extinction across the field. We characterize and quantify this effect using young massive main-sequence stars to derive a statistical reddening correction for most objects in the field. We then search for pre-main-sequence (PMS) stars by looking for objects with a strong (>4{sigma}) H{alpha} excess emission and find about 1150 of them over the entire field. Comparison of their location in the Hertzsprung-Russell diagram with theoretical PMS evolutionary tracks for the appropriate metallicity reveals that about one-third of these objects are younger than {approx}4 Myr, compatible with the age of the massive stars in the central ionizing cluster R 136, whereas the rest have ages up to {approx}30 Myr, with a median age of {approx}12 Myr. This indicates that star formation has proceeded over an extended period of time, although we cannot discriminate between an extended episode and a series of short and frequent bursts that are not resolved in time. While the younger PMS population preferentially occupies the central regions of the cluster, older PMS objects are more uniformly distributed across the field and are remarkably few at the very center of the cluster. We attribute this latter effect to photo-evaporation of the older circumstellar disks caused by the massive ionizing members of R 136.

  10. Formation of the giant planets

    NASA Technical Reports Server (NTRS)

    Lissauer, Jack J.

    2006-01-01

    The observed properties of giant planets, models of their evolution and observations of protoplanetary disks provide constraints on the formation of gas giant planets. The four largest planets in our Solar System contain considerable quantities of hydrogen and helium, which could not have condensed into solid planetesimals within the protoplanetary disk. All three (transiting) extrasolar giant planets with well determined masses and radii also must contain substantial amounts of these light gases. Jupiter and Saturn are mostly hydrogen and helium, but have larger abundances of heavier elements than does the Sun. Neptune and Uranus are primarily composed of heavier elements. HD 149026 b, which is slightly more massive than is Saturn, appears to have comparable quantities of light gases and heavy elements. HD 209458 b and TrES-1 are primarily hydrogen and helium, but may contain supersolar abundances of heavy elements. Spacecraft flybys and observations of satellite orbits provide estimates of the gravitational moments of the giant planets in our Solar System, which in turn provide information on the internal distribution of matter within Jupiter, Saturn, Uranus and Neptune. Atmospheric thermal structure and heat flow measurements constrain the interior temperatures of planets. Internal processes may cause giant planets to become more compositionally differentiated or alternatively more homogeneous; high-pressure laboratory .experiments provide data useful for modeling these processes. The preponderance of evidence supports the core nucleated gas accretion model. According to this model, giant planets begin their growth by the accumulation of small solid bodies, as do terrestrial planets. However, unlike terrestrial planets, the growing giant planet cores become massive enough that they are able to accumulate substantial amounts of gas before the protoplanetary disk dissipates. The primary questions regarding the core nucleated growth model is under what conditions planets with small cores/total heavy element abundances can accrete gaseous envelopes within the lifetimes of gaseous protoplanetary disks.

  11. Quantitative regularities in floodplain formation

    NASA Astrophysics Data System (ADS)

    Nevidimova, O.

    2009-04-01

    Quantitative regularities in floodplain formation Modern methods of the theory of complex systems allow to build mathematical models of complex systems where self-organizing processes are largely determined by nonlinear effects and feedback. However, there exist some factors that exert significant influence on the dynamics of geomorphosystems, but hardly can be adequately expressed in the language of mathematical models. Conceptual modeling allows us to overcome this difficulty. It is based on the methods of synergetic, which, together with the theory of dynamic systems and classical geomorphology, enable to display the dynamics of geomorphological systems. The most adequate for mathematical modeling of complex systems is the concept of model dynamics based on equilibrium. This concept is based on dynamic equilibrium, the tendency to which is observed in the evolution of all geomorphosystems. As an objective law, it is revealed in the evolution of fluvial relief in general, and in river channel processes in particular, demonstrating the ability of these systems to self-organization. Channel process is expressed in the formation of river reaches, rifts, meanders and floodplain. As floodplain is a periodically flooded surface during high waters, it naturally connects river channel with slopes, being one of boundary expressions of the water stream activity. Floodplain dynamics is inseparable from the channel dynamics. It is formed at simultaneous horizontal and vertical displacement of the river channel, that is at Y=Y(x, y), where ?, y - horizontal and vertical coordinates, Y - floodplain height. When d?/dt=0 (for not lowering river channel), the river, being displaced in a horizontal plane, leaves behind a low surface, which flooding during high waters (total duration of flooding) changes from the maximum during the initial moment of time t0 to zero in the moment tn. In a similar manner changed is the total amount of accumulated material on the floodplain surface. Thus, the floodplain dynamics is determined by the amount of material Q(t), left as sediment (amount of warp on a unit of area) during the period of flooding, and the amount of material q(t), removed during the time between floods. With the floodplain height approaching some limit height Yl, which equals the maximal height of floods, ?Q(t) ? 0, ? q(t) ? max. From here, we can build a functional diagram of the floodplain height change depending on time: dY/dt=Q (t) - q (t) (1) This equation allows us to describe non-monotonous behavior of different floodplain massifs. As floodplain systems, like all geomorphosystems, are dissipative structures, they should eventually come to a stable condition: dY/dt=0. This mode is possible in cases: Q=q=0 and Q=q=const. In the first case, the floodplain level would reach the maximum height of flooding and would not be flooded any more. It would cause significant decrease in the amount of material left on its surface as sediments and the system would start to degrade. This variant is purely theoretical, as such conditions, where the streams of matter are absent, can appear only in a homogeneous environment. The second case characterizes the final stage in the formation of floodplain system as an integral unity in concrete external conditions and determines its dynamic equilibrium. In terms of the theory of dynamic systems, this condition corresponds to the limit cycle. Real floodplain systems never achieve it, but approach to it indefinitely closely, repeating themselves and not changing essentially in their basic morphological parameters. Thus, a high floodplain, approaching its limit height, shows morphological completeness. If for any reasons the floodplain surface becomes higher than the limit height Yl, it will not be flooded any more and will become a terrace, which means that the limit cycle of the floodplain system will be destroyed, as well as the system itself. The equation (1) allows to take into account the river incision, accumulation of material onto the floodplain from slopes

  12. On the formation of coronal cavities

    Microsoft Academic Search

    C. H. An; S. T. Suess; E. Tandberg-Hanssen; R. S. Steinolfson

    1986-01-01

    A theoretical study of the formation of a coronal cavity and its relation to a quiescent prominence is presented. It is argued that the formation of a cavity is initiated by the condensation of plasma which is trapped by the coronal magnetic field in a closed streamer and which then flows down to the chromosphere along the field lines due

  13. On the formation of coronal cavities

    Microsoft Academic Search

    C.-H. An; S. T. Suess; E. Tandberg-Hanssen; R. S. Steinolfson

    1985-01-01

    We present a theoretical study of the formation of a coronal cavity and its relation to a quiescent prominence. We argue that the formation of a coronal cavity is initiated by the condensation of plasma which is trapped by the coronal magnetic field in a closed streamer and which then flows down to the chromosphere along the field lines due

  14. On the formation of coronal cavities

    Microsoft Academic Search

    C.-H. An; S. T. Suess; E. Tandberg-Hanssen; R. S. Steinolfson

    1986-01-01

    The authors present a theoretical study of the formation of a coronal cavity and its relation to a quiescent prominence. They argue that the formation of a cavity is initiated by the condensation of plasma which is trapped by the coronal magnetic field in a closed streamer and which then flows down to the chromosphere along the field lines due

  15. HUMAN CAPITAL FORMATION : THE CASE OF QATAR

    Microsoft Academic Search

    Hend A. Jolo

    This paper is an exploratory study that investigates human capital (HC) formation in the state of Qatar. It is carried out with the intention to provide an insight into such a process among Qataris and to ascertain how government's investment in education has been an effective influence on the formation of HC in Qatar. The study provides new evidence about

  16. Planet Formation Is the Solar System Misleading?

    E-print Network

    Wuchterl, Günther

    Planet Formation Is the Solar System Misleading? Günther Wuchterl Max://www.xray.mpe.mpg.de/wuchterl/ Abstract The discovery of more than hundred extrasolar planet candidates chal- lenges our understanding of planet formation. Do we have to modify the theories that were mostly developed for the solar system

  17. Planet formation by concurrent collapse Michael Wilkinson

    E-print Network

    Wilkinson, Michael

    Planet formation by concurrent collapse Michael Wilkinson and Bernhard Mehlig Department the difficulties faced by the conventional theory of planet formation (based upon the aggregation of microscopic dust particles), we describe an alternative hypothesis. We propose that planets form by gravitational

  18. Pore formation in fluctuating membranes Oded Farago

    E-print Network

    Farago, Oded

    in biological membranes is also an important step for drug delivery7 and gene therapy.8 Conse- quently, much adhesion on porous or decorated substrates,18,19 and osmotic swelling.20,21 Most theories of pore formation'' . The formation of a circular hole of radius r0 is driven by the reduction in the tension energy r0 2

  19. Trajectory formation and handwriting: A computational model

    Microsoft Academic Search

    P. Morasso; F. A. Mussa Ivaldi

    1982-01-01

    This paper proposes a computational model for different aspects of trajectory formation, from point-to-point movements to handwriting. The proposed model is based on a mechanism of composition of basic curve elements (strokes) which separates the spatial and the temporal aspects of trajectory formation. At the same time, the model suggests a method for storing and describing arm movements, as a

  20. Formation of Globular Clusters in Galaxy Mergers

    Microsoft Academic Search

    Yuexing Li; Mordecai-Mark Mac Low; Ralf S. Klessen

    2004-01-01

    We present a high-resolution simulation of globular cluster formation in a galaxy merger. For the first time in such a simulation, individual star clusters are directly identified and followed on their orbits. We quantitatively compare star formation in the merger to that in the unperturbed galaxies. The merging galaxies show a strong starburst, in sharp contrast to their isolated progenitors.

  1. Island Formation: Constructing a Coral Island

    ERIC Educational Resources Information Center

    Austin, Heather; Edd, Amelia

    2009-01-01

    The process of coral island formation is often difficult for middle school students to comprehend. Coral island formation is a dynamic process, and students should have the opportunity to experience this process in a synergistic context. The authors provide instructional guidelines for constructing a coral island. Students play an interactive role…

  2. Insights from Simulations of Star Formation

    E-print Network

    Richard B. Larson

    2007-02-07

    Although the basic physics of star formation is classical, numerical simulations have yielded essential insights into how stars form. They show that star formation is a highly nonuniform runaway process characterized by the emergence of nearly singular peaks in density, followed by the accretional growth of embryo stars that form at these density peaks. Circumstellar disks often form from the gas being accreted by the forming stars, and accretion from these disks may be episodic, driven by gravitational instabilities or by protostellar interactions. Star-forming clouds typically develop filamentary structures, which may, along with the thermal physics, play an important role in the origin of stellar masses because of the sensitivity of filament fragmentation to temperature variations. Simulations of the formation of star clusters show that the most massive stars form by continuing accretion in the dense cluster cores, and this again is a runaway process that couples star formation and cluster formation. Star-forming clouds also tend to develop hierarchical structures, and smaller groups of forming objects tend to merge into progressively larger ones, a generic feature of self-gravitating systems that is common to star formation and galaxy formation. Because of the large range of scales and the complex dynamics involved, analytic models cannot adequately describe many processes of star formation, and detailed numerical simulations are needed to advance our understanding of the subject.

  3. APPREND: Formative Assessment Tools for APP

    ERIC Educational Resources Information Center

    Sherborne, Tony

    2009-01-01

    This article discusses how Assessing Pupils' Progress (APP) can be turned into more of a tool for formative assessment. It describes an approach called "APPREND" as a set of APP-based tools for formative assessment. The author provides a glimpse of how APPREND tools can help. (Contains 2 tables.)

  4. Achievement Goal Orientations and Identity Formation Styles

    ERIC Educational Resources Information Center

    Kaplan, Avi; Flum, Hanoch

    2010-01-01

    The present article points to shared underlying theoretical assumptions and central processes of a prominent academic motivation perspective--achievement goal theory--and recent process perspectives in the identity formation literature, and more specifically, identity formation styles. The review highlights the shared definition of achievement…

  5. Formation and evolution of the protoplanetary disk

    NASA Technical Reports Server (NTRS)

    Ruzmaikina, Tamara V.; Makalkin, A. B.

    1991-01-01

    A disk formation model during collapse of the protosolar nebula, yielding a low-mass protoplanetary disk is presented. The following subject areas are covered: (1) circumstellar disks; (2) conditions for the formation of stars with disks; (3) early evolution of the protoplanetary disk; and (4) temperature conditions and the convection in the protoplanetary disk.

  6. EUDISED: Standards, Format, Character Representation, 1973.

    ERIC Educational Resources Information Center

    Council of Europe, Strasbourg (France). Documentation Center for Education in Europe.

    Part of a larger effort in creating a computer-based European Documentation and Information System for Education (EUDISED), the present document is the report of the Working Party on formats and standards. It presents draft recommendations on general system standards: transmission standards (interchange format, magnetic tape standards, tape labels…

  7. DISSERTATION FORMATION OF THE HURRICANE EYE

    E-print Network

    Schubert, Wayne H.

    DISSERTATION FORMATION OF THE HURRICANE EYE Submitted by Jonathan L. Vigh Department of Atmospheric OF THE HURRICANE EYE BE ACCEPTED AS FULFILLING IN PART REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY. Schubert Department Head: Richard H. Johnson ii #12;ABSTRACT OF DISSERTATION FORMATION OF THE HURRICANE EYE

  8. Learning Progressions that Support Formative Assessment Practices

    ERIC Educational Resources Information Center

    Alonzo, Alicia C.

    2011-01-01

    Black, Wilson, and Yao (this issue) lay out a comprehensive vision for the way that learning progressions (or other "road maps") might be used to inform and coordinate formative and summative purposes of assessment. As Black, Wilson, and others have been arguing for over a decade, the effective use of formative assessment has great potential to…

  9. Molecular mechanisms of Staphylococcus epidermidis biofilm formation

    Microsoft Academic Search

    D. Mack

    1999-01-01

    Coagulase-negative staphylococci, mainly Staphylococcus epidermidis, are the predominant cause of implanted medical-device related infections. The formation of adherent multilayered biofilms embedded into a glycocalyx composed of exopolysaccharides on implanted devices is believed to be essential for the pathogenesis of S. epidermidis infections. Biofilm formation may be separated into primary attachment of bacteria to native or modified polymer surfaces followed by

  10. Methods for forming wellbores in heated formations

    DOEpatents

    Guimerans, Rosalvina Ramona; Mansure, Arthur James

    2012-09-25

    A method for forming a wellbore in a heated formation includes flowing liquid cooling fluid to a bottom hole assembly in a wellbore in a heated formation. At least a portion of the liquid cooling fluid is vaporized at or near a region to be cooled. Vaporizing the liquid cooling fluid absorbs heat from the region to be cooled.

  11. Sequence Determinants of Bacterial Amyloid Formation

    Microsoft Academic Search

    Xuan Wang; Matthew R. Chapman

    2008-01-01

    Amyloids are proteinaceous fibers commonly associated with neurodegenerative diseases and prion-based encephalopathies. Many different polypeptides can form amyloid fibers, leading to the suggestion that amyloid is a primitive main chain-dominated structure. A growing body of evidence suggests that amino acid side chains dramatically influence amyloid formation. The specific role fulfilled by side chains in amyloid formation, especially in vivo, remains

  12. Formation of $??$ atoms in $K_{?4} decay

    E-print Network

    S. R. Gevorkyan; A. V. Tarasov; O. O. Voskresenskaya

    2009-12-01

    We derive the decay rate of $\\pi\\mu$ atom formation in $K_{\\mu 4}$ decay. Using the obtained expressions we calculate the decay rate of atom formation and point out that considered decay can give a noticeable contribution as a background to the fundamental decay $K^+\\to \\pi^+\

  13. Bluetooth scatternet formation for supporting device mobility

    Microsoft Academic Search

    Chorng-horng Yang; Yi-sheng Chen

    2005-01-01

    Since most of the Bluetooth devices are portable, the user may bring the Bluetooth devices and roams in the range of a scatternet. Thus, the capability of formatting Bluetooth scatternet under device mobility impacts on the survivability and feasibility of the Bluetooth network. In this paper, we propose a formation algorithm that can construct the Bluetooth scatternet subject to device

  14. Harnessing Collaborative Annotations on Online Formative Assessments

    ERIC Educational Resources Information Center

    Lin, Jian-Wei; Lai, Yuan-Cheng

    2013-01-01

    This paper harnesses collaborative annotations by students as learning feedback on online formative assessments to improve the learning achievements of students. Through the developed Web platform, students can conduct formative assessments, collaboratively annotate, and review historical records in a convenient way, while teachers can generate…

  15. Formative E-Assessment: Practitioner Cases

    ERIC Educational Resources Information Center

    Pachler, Norbert; Daly, Caroline; Mor, Yishay; Mellar, Harvey

    2010-01-01

    This paper reports on one aspect of the Joint Information Systems Committee (JISC)-funded project "Scoping a vision of formative e-assessment", namely on cases of formative e-assessment developed iteratively with the UK education practitioner community. The project, which took place from June 2008 to January 2009, aimed to identify current…

  16. Mylonitic Breccia near the Gunsight Formation

    USGS Multimedia Gallery

    Mylonitic breccia in alluvium of Little Deer Creek, downstream from a moderately west-dipping contact between biotitic quartzite of the Gunsight Formation, which is structurally overlain by garnet-chloritoid-bearing banded siltite of the banded siltite unit of the Apple Creek Formation. That structu...

  17. 21 CFR 186.1756 - Sodium formate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...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 used as a constituent of...

  18. 21 CFR 186.1756 - Sodium formate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...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 used as a constituent of...

  19. 21 CFR 186.1756 - Sodium formate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...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 used as a constituent of...

  20. 21 CFR 186.1756 - Sodium formate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...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 used as a constituent of...

  1. 21 CFR 186.1756 - Sodium formate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...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 used as a constituent of...

  2. FAINT RADIO SOURCES AND STAR FORMATION HISTORY

    E-print Network

    Waddington, Ian

    FAINT RADIO SOURCES AND STAR FORMATION HISTORY Deborah B. Haarsma 1 , R. Bruce Partridge 1 , Ian 85287­1504 USA Abstract. Faint extragalactic radio sources provide important information about the global history of star formation. Sensitive radio observations of the Hubble Deep Field and other fields

  3. NO formation during agricultural straw combustion

    Microsoft Academic Search

    Qiangqiang Ren; Changsui Zhao; Lunbo Duan; Xiaoping Chen

    2011-01-01

    NO formation during combustion of four typical kinds of straw (wheat straw, rice straw, cotton stalk and corn stalk) which belong to soft straw and hard straw was studied in a tubular quartz fixed bed reactor under conditions relevant to grate boiler combustion. Regarding the real situation in biomass fired power plants in China, NO formation from blended straw combustion

  4. Formation and evaporation of charged black holes

    Microsoft Academic Search

    Evgeny Sorkin; Tsvi Piran

    2001-01-01

    We investigate the dynamical formation and evaporation of a spherically symmetric charged black hole. We study the self-consistent one loop order semiclassical back reaction problem. To this end the mass evaporation is modeled by an expectation value of the stress-energy tensor of a neutral massless scalar field, while the charge is not radiated away. We observe the formation of an

  5. Teaching Literature in the Intensive Weekend Format.

    ERIC Educational Resources Information Center

    Brown, Dorothy H.

    Although the notion of teaching literature in an intensive weekend format may present numerous problems to be solved by the instructor, it can be a format that results in considerable success. It is conducive to the schedules of many students who work during the week, and weekend literature courses have proven to be popular. Intensive weekend…

  6. Prevention of biofilm formation by polymer modification

    Microsoft Academic Search

    B Jansen; W Kohnen

    1995-01-01

    Bacterial biofilm formation on synthetic polymers plays an important role in industry and in modern medicine, leading, for example, to difficult-to-treat infections caused by colonized foreign bodies. Prevention of biofilm formation is a necessary step in the successful prophylaxis of such infections. One approach is to inhibit bacterial adherence by polymer surface modification. We have investigated polymer modification by glow

  7. Autonomous Helicopter Formation using Model Predictive Control

    E-print Network

    Sastry, S. Shankar

    Autonomous Helicopter Formation using Model Predictive Control Hoam Chung and S. Shankar Sastry for teams of helicopters. However, the potential for accidents is greatly increased when helicopter teams to the problem of helicopter formations comprised of heterogenous vehicles. The disturbance attenuation property

  8. A UNIMARC Bibliographic Format Database for ABCD

    ERIC Educational Resources Information Center

    Megnigbeto, Eustache

    2012-01-01

    Purpose: ABCD is a web-based open and free software suite for library management derived from the UNESCO CDS/ISIS software technology. The first version was launched officially in December 2009 with a MARC 21 bibliographic format database. This paper aims to detail the building of the UNIMARC bibliographic format database for ABCD.…

  9. Formation of thaumasite in carbonated mortars

    Microsoft Academic Search

    J Aguilera; S Mart??nez-Ram??rez; I Pajares-Colomo; M. T Blanco-Varela

    2003-01-01

    The main objective of this study was to investigate the formation of thaumasite in carbonated Portland cement mortars. Another important purpose was to study the role that ettringite (AFt) plays in the process of formation of Th and its influence in the deterioration of the mortars.Work was carried out with mortar prisms, elaborated using two different cements: one of them

  10. LARSPEC spectroradiometer-multiband radiometer data formats

    NASA Technical Reports Server (NTRS)

    Biehl, L. L.

    1982-01-01

    The data base software system, LARSPEC, is discussed and the data base format for agronomic, meteorological, spectroradiometer, and multiband radiometer data is described. In addition, the contents and formats of each record of data and the wavelength tables are listed and the codes used for some of the parameters are described.

  11. A format for scripted clinical oral examinations.

    PubMed

    Elks, M L; Sawyer, J W

    1993-03-01

    A format for scripted clinical oral examination in general medicine is presented. Using this format, untutored pairs of teachers were consistent in grading third-year clerkship students. This measure of performance appeared to evaluate an aspect of clinical skills not assessed by the National Board Medical Examination or clinical performance assessments. Acceptance by teachers was good. PMID:8336562

  12. Spiral arm triggering of star formation

    E-print Network

    Ian A. Bonnell

    2006-11-07

    We present numerical simulations of the passage of clumpy gas through a galactic spiral shock, the subsequent formation of giant molecular clouds (GMCs) and the triggering of star formation. The spiral shock forms dense clouds while dissipating kinetic energy, producing regions that are locally gravitationally bound and collapse to form stars. In addition to triggering the star formation process, the clumpy gas passing through the shock naturally generates the observed velocity dispersion size relation of molecular clouds. In this scenario, the internal motions of GMCs need not be turbulent in nature. The coupling of the clouds' internal kinematics to their externally triggered formation removes the need for the clouds to be self-gravitating. Globally unbound molecular clouds provides a simple explanation of the low efficiency of star formation. While dense regions in the shock become bound and collapse to form stars, the majority of the gas disperses as it leaves the spiral arm.

  13. Star Formation in Transient Molecular Clouds

    E-print Network

    Paul C. Clark; Ian A. Bonnell

    2003-11-12

    We present the results of a numerical simulation in which star formation proceeds from an initially unbound molecular cloud core. The turbulent motions, which dominate the dynamics, dissipate in shocks leaving a quiescent region which becomes gravitationally bound and collapses to form a small multiple system. Meanwhile, the bulk of the cloud escapes due to its initial supersonic velocities. In this simulation, the process naturally results in a star formation efficiency of 50%. The mass involved in star formation depends on the gas fraction that dissipates sufficient kinetic energy in shocks. Thus, clouds with larger turbulent motions will result in lower star formation efficiencies. This implies that globally unbound, and therefore transient giant molecular clouds (GMCs), can account for the low efficiency of star formation observed in our Galaxy without recourse to magnetic fields or feedback processes. Observations of the dynamic stability in molecular regions suggest that GMCs may not be self-gravitating, supporting the ideas presented in this letter.

  14. Molecular cloud evolution and star formation

    NASA Technical Reports Server (NTRS)

    Silk, J.

    1985-01-01

    The present state of knowledge of the relationship between molecular clouds and young stars is reviewed. The determination of physical parameters from molecular line observations is summarized, and evidence for fragmentation of molecular clouds is discussed. Hierarchical fragmentation is reviewed, minimum fragment scales are derived, and the stability against fragmentation of both spherically and anisotropically collapsing clouds is discussed. Observational evidence for high-velocity flows in clouds is summarized, and the effects of winds from pre-main sequence stars on molecular gas are discussed. The triggering of cloud collapse by enhanced pressure is addressed, as is the formation of dense shells by spherical outflows and their subsequent breakup. A model for low-mass star formation is presented, and constraints on star formation from the initial mass function are examined. The properties of giant molecular clouds and massive star formation are described. The implications of magnetic fields for cloud evolution and star formation are addressed.

  15. Star Formation in Southern Seyfert Galaxies

    E-print Network

    Duncan Forbes; Ray Norris

    1998-04-28

    We have produced radio maps, using the ATCA, of the central regions of six southern Seyfert 2 galaxies (NGC 1365, 4945, 6221, 6810, 7582, and Circinus) with circumnuclear star formation, to estimate the relative contribution of star formation activity compared to activity from the active galactic nucleus (AGN). The radio morphologies range from extended diffuse structures to compact nuclear emission, with no evidence, even in the relatively compact sources, for synchrotron self--absorption. In each case the radio to far--infrared (FIR) ratio has a value consistent with star formation, and in all but one case the radio to [FeII] ratio is also consistent with star formation. We derive supernova rates and conclude that, despite the presence of a Seyfert nucleus in these galaxies, the radio, FIR, and [FeII] line emission are dominated by processes associated with the circumnuclear star formation (i.e. supernova remnants and HII regions) rather than with the AGN.

  16. Massive Star Formation in the Galactic Center

    E-print Network

    D. F. Figer

    2008-03-12

    The Galactic center is a hotbed of star formation activity, containing the most massive star formation site and three of the most massive young star clusters in the Galaxy. Given such a rich environment, it contains more stars with initial masses above 100 \\Msun than anywhere else in the Galaxy. This review concerns the young stellar population in the Galactic center, as it relates to massive star formation in the region. The sample includes stars in the three massive stellar clusters, the population of younger stars in the present sites of star formation, the stars surrounding the central black hole, and the bulk of the stars in the field population. The fossil record in the Galactic center suggests that the recently formed massive stars there are present-day examples of similar populations that must have been formed through star formation episodes stretching back to the time period when the Galaxy was forming.

  17. XML-based DICOM data format.

    PubMed

    Yu, Cong; Yao, Zhihong

    2010-04-01

    To enhance the readability, improve the structure, and facilitate the sharing of digital imaging and communications in medicine (DICOM) files, this research proposed one kind of XML-based DICOM data format. Because XML Schema offers great flexibility for expressing constraints on the content model of elements, we used it to describe the new format, thus making it consistent with the one originally defined by DICOM. Meanwhile, such schemas can be used in the creation and validation of the XML-encoded DICOM files, acting as a standard for data transmission and sharing on the Web. Upon defining the new data format, we started with representing a single data element and further improved the whole data structure with the method of modularization. In contrast to the original format, the new one possesses better structure without loss of related information. In addition, we demonstrated the application of XSLT and XQuery. All of the advantages mentioned above resulted from this new data format. PMID:19184223

  18. Biofilm formation by vaginal Lactobacillus in vivo.

    PubMed

    Ventolini, G; Mitchell, E; Salazar, M

    2015-05-01

    Biofilm formation by nonpathogenic bacteria is responsible for their stable maintenance in vivo ecosystems as it promotes long-term permanence on the host's vaginal mucosa. Biofilm formation by Lactobacilli has been reported in vitro but not in vivo. We hypothesize the presence of biofilm formation in vivo could be also documented by microscope photographs (MP) of wet mounts obtained from uninfected vaginal samples satisfying rigorous scientific identification criteria. We analyzed 400 MP from our database, and we were able to determine that 12 MP from 6 different patients contained clues of the formation of biofilm by Lactobacilli. The most probable lactobacillus involved is presumed to be Lactobacillus jensenii. The documentation of biofilm formation by vaginal Lactobacilli at fresh wet mount preparation is significant and has several important clinical preventive and therapeutic implications. PMID:25725906

  19. Maintenance of satellite formations using environmental forces

    NASA Astrophysics Data System (ADS)

    Kumar, Krishna D.; Misra, Arun K.; Varma, Surjit; Reid, Tyler; Bellefeuille, Francis

    2014-09-01

    This paper examines the maintenance of satellite formations using two environmental forces: solar radiation pressure and aerodynamic forces. It is assumed that the satellites are equipped with solar flaps or aerodynamic flaps. Control using aerodynamic flaps is considered for satellite formations in LEO while solar flaps is applied to formations in LEO as well as GEO. The simple control laws based on open-loop and closed-loop control methods are designed for required rotation of the flaps to achieve desired formation keeping. The feasibility of the proposed schemes is proven via stability analyses followed by numerical simulations. A linear flap rotation scheme is found to keep the relative position errors bounded to ±5 m. The proposed control methods show the effectiveness of the use of solar radiation pressure and aerodynamic forces for satellite formation flying.

  20. Optimal Configurations for Rotating Spacecraft Formations

    NASA Technical Reports Server (NTRS)

    Hughes, Steven P.; Hall, Christopher D.

    2000-01-01

    In this paper a new class of formations that maintain a constant shape as viewed from the Earth is introduced. An algorithm is developed to place n spacecraft in a constant shape formation spaced equally in time using the classical orbital elements. To first order, the dimensions of the formation are shown to be simple functions of orbit eccentricity and inclination. The performance of the formation is investigated over a Keplerian orbit using a performance measure based on a weighted average of the angular separations between spacecraft in formation. Analytic approximations are developed that yield optimum configurations for different values of n. The analytic approximations are shown to be in excellent agreement with the exact solutions.

  1. Relative Navigation of Formation-Flying Satellites

    NASA Technical Reports Server (NTRS)

    Long, Anne; Kelbel, David; Lee, Taesul; Leung, Dominic; Carpenter, J. Russell; Grambling, Cheryl

    2002-01-01

    This paper compares autonomous relative navigation performance for formations in eccentric, medium and high-altitude Earth orbits using Global Positioning System (GPS) Standard Positioning Service (SPS), crosslink, and celestial object measurements. For close formations, the relative navigation accuracy is highly dependent on the magnitude of the uncorrelated measurement errors. A relative navigation position accuracy of better than 10 centimeters root-mean-square (RMS) can be achieved for medium-altitude formations that can continuously track at least one GPS signal. A relative navigation position accuracy of better than 15 meters RMS can be achieved for high-altitude formations that have sparse tracking of the GPS signals. The addition of crosslink measurements can significantly improve relative navigation accuracy for formations that use sparse GPS tracking or celestial object measurements for absolute navigation.

  2. Beyond the identification of formation processes: Behavioral inference based on traces left by cultural formation processes

    Microsoft Academic Search

    Masakazu Tani

    1995-01-01

    Formation processes are generally considered as a negative factor for behavioral inference in archaeology. The concept of formation processes, however, can potentially be far more useful for behavioral inference in archaeology than simply identifying spurious variability in the archaeological record. Physical traces left by cultural formation processes convey a certain kind of behavioral information which may not be otherwise available.

  3. Procedures for Designing Course Evaluation Instruments: Masked Personality Format Versus Transparent Achievement Format

    Microsoft Academic Search

    Lou M. Carey; Robert F. Dedrick; James O. Carey; Susan N. Kushner

    1994-01-01

    One important consideration in designing instruments to measure students' attitudes about a course or an instructor is the influence of the format of the instrument on students' responses. This study contrasted the effects of randomly distributing the items throughout the questionnaire (personality format) versus grouping the items together from the same dimension (achievement format) on students' end-of-term course evaluations. On

  4. Photogeneration of active formate decomposition catalysts to produce hydrogen from formate and water

    DOEpatents

    King, Jr., Allen D. (Athens, GA); King, Robert B. (Athens, GA); Sailers, III, Earl L. (Athens, GA)

    1983-02-08

    A process for producing hydrogen from formate and water by photogenerating an active formate decomposition catalyst from transition metal carbonyl precursor catalysts at relatively low temperatures and otherwise mild conditions is disclosed. Additionally, this process may be expanded to include the generation of formate from carbon monoxide and hydroxide such that the result is the water gas shift reaction.

  5. PROBA-3: Precise formation flying demonstration mission

    NASA Astrophysics Data System (ADS)

    Llorente, J. S.; Agenjo, A.; Carrascosa, C.; de Negueruela, C.; Mestreau-Garreau, A.; Cropp, A.; Santovincenzo, A.

    2013-01-01

    Formation Flying (FF) has generated a strong interest in many space applications, most of them involving a significant complexity for building for example on-board large "virtual structures or distributed observatories". The implementation of these complex formation flying missions with critical dependency on this new, advanced and critical formation technology requires a thorough verification of the system behaviour in order to provide enough guarantees for the target mission success. A significant number of conceptual or preliminary designs, analyses, simulations, and HW on-ground testing have been performed during the last years, but still the limitations of the ground verification determine that enough confidence of the behaviour of the formation flying mission will only be possible by demonstration in flight of the concept and the associated technologies. PROBA-3 is the mission under development at ESA for in-flight formation flying demonstration, dedicated to obtain that confidence and the necessary flight maturity level in the formation flying technologies for those future target missions. PROBA-3 will demonstrate technologies such as formation metrology sensors (from very coarse to highest accuracy), formation control and GNC, system operability, safety, etc. During the last years, PROBA-3 has evolved from the initial CDF study at ESA, to two parallel phase A studies, followed by a change in the industrial configuration for the Bridging step between A and B phases. Currently the SRR consolidation has been completed, and the project is in the middle of the phase B. After the phase A study SENER and GMV were responsible for the Formation Flying System, within a mission core team completed by OHB-Sweden, QinetiQ Space and CASA Espacio. In this paper an overview of the PROBA-3 mission is provided, with a more detailed description of the formation flying preliminary design and results.

  6. Formation of parting in quartz

    NASA Astrophysics Data System (ADS)

    Jørgen Kjøll, Hans; Eske Sørensen, Bjørn

    2014-05-01

    This paper presents hydrothermal quartz with macroscopic planar parting from the Mesoproterozoic Modum complex in southern Norway. Similar macroscopic parting in hydrothermal quartz with macroscopic planar structures has only been described from two localities in the world; Madagascar (Flörke et al., 1981) and Southern California (Murdoch et al., 1938). The study area consists of well foliated and banded sillimanite- garnet- amphibolite- mica gneiss that is cut at high angle by hydrothermal veins containing albite, chlinoclore, hornblende, hydroxyl apatite and quartz. The rim of the veins is generally made up of almost pure end-member euhedral albite. Then there is vugs with euhedral hornblende (10-25cm long) and euhedral hydroxyl apatite with size ranging from mm scale to several cm. Some places the quartz encloses apatite and hornblende. The quartz is anhedral, inequigranular with undulose extinction bordering sub grain rotation. It has large planar penetrative parting faces with pearly luster; however this is not consistent throughout the outcrop and some places the penetrative faces disappears and the quartz has a conchoidal fracture. The planar faces continue throughout the specimens with a few mm spacing. Thin sections oriented perpendicular to the most pronounced planar structure show lamellas that extinguishes at small angles (2 degrees) to each other. EBSD mapping of the planar faces shows two orientations {0-111} and {1-101}, corresponding to the r- and z-faces respectively, separated by irregular boundaries. The misorientation between these two crystallographic orientations on the parting is a 60 degree rotation on [0 0 1] in correspondence to the dauphiné twin law. Investigations conducted on thin sections cut orthogonal to the parting shows that the parting cuts and offsets the dauphiné twins, indicating a late genesis of the parting. However some internal stress induced movement of the twins are visible. SEM-CL documents three generations of quartz and two, possibly three, planar structures; two evident, one more obscure. The most prominent of the three appears to cut across the recrystallization, offsetting the recrystallization textures with varying distances. We propose a very late formation of the parting due to its crosscutting relationship with all features, such as recrystallized quartz, secondary fluid inclusion trails and twins. The parting develops in crystals that are optimally oriented with respect to ?1 in a fast, low temperature deformation event.

  7. Is acetylene essential for carbon dust formation?

    NASA Astrophysics Data System (ADS)

    Dhanoa, H.; Rawlings, J. M. C.

    2014-05-01

    We have carried out an investigation of the chemical evolution of gas in different carbon-rich circumstellar environments. Previous studies have tended to invoke terrestrial flame chemistries, based on acetylene (C2H2) combustion to model the formation of carbon dust, via polycyclic aromatic hydrocarbons (PAHs). In this work, we pay careful attention to the accurate calculation of the molecular photoreaction rate coefficients to ascertain whether there is a universal formation mechanism for carbon dust in strongly irradiated astrophysical environments. A large number of possible chemical channels may exist for the formation of PAHs, so we have concentrated on the viability of the formation of the smallest building block species, C2H2, in a variety of carbon-rich stellar outflows. C2H2 is very sensitive to dissociation by UV radiation. This sensitivity is tested, using models of the time-dependent chemistry. We find that C2H2 formation is sensitive to some of the physical parameters and that in some known sources of dust formation it can never attain appreciable abundances. Therefore, multiple (and currently ill-defined) dust-formation channels must exist.

  8. Local Estimators for Spacecraft Formation Flying

    NASA Technical Reports Server (NTRS)

    Fathpour, Nanaz; Hadaegh, Fred Y.; Mesbahi, Mehran; Nabi, Marzieh

    2011-01-01

    A formation estimation architecture for formation flying builds upon the local information exchange among multiple local estimators. Spacecraft formation flying involves the coordination of states among multiple spacecraft through relative sensing, inter-spacecraft communication, and control. Most existing formation flying estimation algorithms can only be supported via highly centralized, all-to-all, static relative sensing. New algorithms are needed that are scalable, modular, and robust to variations in the topology and link characteristics of the formation exchange network. These distributed algorithms should rely on a local information-exchange network, relaxing the assumptions on existing algorithms. In this research, it was shown that only local observability is required to design a formation estimator and control law. The approach relies on breaking up the overall information-exchange network into sequence of local subnetworks, and invoking an agreement-type filter to reach consensus among local estimators within each local network. State estimates were obtained by a set of local measurements that were passed through a set of communicating Kalman filters to reach an overall state estimation for the formation. An optimization approach was also presented by means of which diffused estimates over the network can be incorporated in the local estimates obtained by each estimator via local measurements. This approach compares favorably with that obtained by a centralized Kalman filter, which requires complete knowledge of the raw measurement available to each estimator.

  9. The Migrating Embryo Model for Planet Formation

    NASA Astrophysics Data System (ADS)

    Basu, Shantanu; Vorobyov, E.

    2014-01-01

    A new view of disk evolution and planet formation is emerging from self-consistent numerical simulation modeling of the formation of circumstellar disks from the direct collapse of prestellar cloud cores. A defining result is that the early evolution of a disk is crucially affected by the continuing mass loading from the core envelope, with recurrent phases of gravitational instability occurring in the disk. Nonlinear spiral arms formed during these episodes fragment to form gaseous clumps. These clumps generally migrate inward due to gravitational torques arising from their interaction with a trailing spiral arm. Occasionally, a clump can open up a gap in the disk and settle into a stable orbit, revealing a direct pathway to the formation of companion stars, brown dwarfs, or giant planets. At other times, when multiple clumps are present, a low mass clump may even be ejected from the system, providing a pathway to the formation of free-floating brown dwarfs and giant planets in addition to low mass stars. Finally, the inward migration of gaseous clumps may provide the proper conditions for the transport of high-temperature processed solids from the outer disk to the inner disk, and even possibly accelerate the formation of terrestrial planets in the inner disk. All of these features arising from clump formation and migration can be tied together conceptually in a migrating embryo model that can complement the well-known core accretion model for planet formation.

  10. Cluster formation versus star formation around six regions in the Large Magellanic Cloud

    E-print Network

    Annapurni Subramaniam

    2002-03-19

    We studied the stellar population and star clusters around six regions in the Large Magellanic Cloud (LMC) in order to understand the correlation between star formation and cluster formation episodes. We used the stellar data base of OGLE II LMC survey and the star cluster catalogues. The analysis of the colour-magnitude diagrams (CMDs) were used to estimate the ages of the stellar population. It is found that most of the regions have undergone three major star formation episodes. The star formation which began about 4 Gyr ago, continued upto 1 Gyr, or continued further. The other two events have taken place around 300 Myr, and 100 Myr. A few star clusters were formed during the first of the three star formation events in 5 regions. On all the six regions, a good correlation is seen between the star and cluster formation events which occurred at 300 Myr and 100 Myr. The cluster formation events and the fraction of star clusters formed were found to be very similar for two regions located to the south-east of the Bar, suggesting similar cluster formation triggers at almost similar instances. The two recent star formation events seem to correlate with the interaction of LMC with Small Magellanic Cloud (SMC) and Galaxy. Hence it is quite likely that the young populous star clusters in the LMC are formed as a result of the star formation events started due to galaxy-galaxy interactions and the further propagation of such star formation.

  11. WORM - WINDOWED OBSERVATION OF RELATIVE MOTION

    NASA Technical Reports Server (NTRS)

    Bauer, F.

    1994-01-01

    The Windowed Observation of Relative Motion, WORM, program is primarily intended for the generation of simple X-Y plots from data created by other programs. It allows the user to label, zoom, and change the scale of various plots. Three dimensional contour and line plots are provided, although with more limited capabilities. The input data can be in binary or ASCII format, although all data must be in the same format. A great deal of control over the details of the plot is provided, such as gridding, size of tick marks, colors, log/semilog capability, time tagging, and multiple and phase plane plots. Many color and monochrome graphics terminals and hard copy printer/plotters are supported. The WORM executive commands, menu selections and macro files can be used to develop plots and tabular data, query the WORM Help library, retrieve data from input files, and invoke VAX DCL commands. WORM generated plots are displayed on local graphics terminals and can be copied using standard hard copy capabilities. Some of the graphics features of WORM include: zooming and dezooming various portions of the plot; plot documentation including curve labeling and function listing; multiple curves on the same plot; windowing of multiple plots and insets of the same plot; displaying a specific on a curve; and spinning the curve left, right, up, and down. WORM is written in PASCAL for interactive execution and has been implemented on a DEC VAX computer operating under VMS 4.7 with a virtual memory requirement of approximately 392K of 8 bit bytes. It uses the QPLOT device independent graphics library included with WORM. It was developed in 1988.

  12. Parallel Estimators and Communication in Spacecraft Formations

    NASA Technical Reports Server (NTRS)

    Smith, Roy S.; Hadaegh, Fred Y.

    2005-01-01

    This paper investigates the closed-loop dynamics of systems controlled via parallel estimators. This structure arises in formation flying problems when each spacecraft bases its control action on an internal estimate of the complete formation state. For LTI systems a separation principle shows that the necessary and sufficient conditions for overall system stability are more stringent than the single controller case; the controllers' open-loop dynamics necessarily appear in the closed-loop dynamics. Communication amongst the spacecraft can be used to specify the complete system dynamics and a framework for integrating the design of the communication links into the formation flying control design problem is presented.

  13. Inhibition of bone formation during space flight

    NASA Technical Reports Server (NTRS)

    Morey, E. R.; Baylink, D. J.

    1978-01-01

    Parameters of bone formation and resorption were measured in rats orbited for 19.5 days aboard the Soviet Cosmos 782 biological satellite. The most striking effects were on bone formation. During flight, rats formed significantly less periosteal bone than did control rats on the ground. An arrest line at both the periosteum and the endosteum of flight animals suggests that a complete cecessation of bone growth occurred. During a 26-day postflight period, the defect in bone formation was corrected. No significant changes in bone resorption were observed.

  14. The Center for Star Formation Studies

    NASA Technical Reports Server (NTRS)

    Hollenbach, D.; Bell, K. R.; Laughlin, G.

    2002-01-01

    The Center for Star Formation Studies, a consortium of scientists from the Space Science Division at Ames and the Astronomy Departments of the University of California at Berkeley and Santa Cruz, conducts a coordinated program of theoretical research on star and planet formation. Under the directorship of D. Hollenbach (Ames), the Center supports postdoctoral fellows, senior visitors, and students; meets regularly at Ames to exchange ideas and to present informal seminars on current research; hosts visits of outside scientists; and conducts a week-long workshop on selected aspects of star and planet formation each summer.

  15. Star Formation in Henize 206

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site] IRA-MIPS Composite

    [figure removed for brevity, see original site] Visible

    [figure removed for brevity, see original site] IRAC

    [figure removed for brevity, see original site] MIPS

    The LMC is a small satellite galaxy gravitationally bound to our own Milky Way. Yet the gravitational effects are tearing the companion to shreds in a long-playing drama of 'intergalactic cannibalism.' These disruptions lead to a recurring cycle of star birth and star death.

    Astronomers are particularly interested in the LMC because its fractional content of heavy metals is two to five times lower than is seen in our solar neighborhood. [In this context, 'heavy elements' refer to those elements not present in the primordial universe. Such elements as carbon, oxygen and others are produced by nucleosynthesis and are ejected into the interstellar medium via mass loss by stars, including supernova explosions.] As such, the LMC provides a nearby cosmic laboratory that may resemble the distant universe in its chemical composition.

    The primary Spitzer image, showing the wispy filamentary structure of Henize 206, is a four-color composite mosaic created by combining data from an infrared array camera (IRAC) at near-infrared wavelengths and the mid-infrared data from a multiband imaging photometer (MIPS). Blue represents invisible infrared light at wavelengths of 3.6 and 4.5 microns. Note that most of the stars in the field of view radiate primarily at these short infrared wavelengths. Cyan denotes emission at 5.8 microns, green depicts the 8.0 micron light, and red is used to trace the thermal emission from dust at 24 microns. The separate instrument images are included as insets to the main composite.

    An inclined ring of emission dominates the central and upper regions of the image. This delineates a bubble of hot, x-ray emitting gas that was blown into space when a massive star died in a supernova explosion millions of years ago. The shock waves from that explosion impacted a cloud of nearby hydrogen gas, compressed it, and started a new generation of star formation. The death of one star led to the birth of many new stars. This is particularly evident in the MIPS inset, where the 24-micron emission peaks correspond to newly formed stars. The ultraviolet and visible-light photons from the new stars are absorbed by surrounding dust and re-radiated at longer infrared wavelengths, where it is detected by Spitzer.

    This emission nebula was cataloged by Karl Henize (HEN-eyes) while spending 1948-1951 in South Africa doing research for his Ph.D. dissertation at the University of Michigan. Henize later became a NASA astronaut and, at age 59, became the oldest rookie to fly on the Space Shuttle during an eight-day flight of the Challenger in 1985. He died just short of his 67th birthday in 1993 while attempting to climb the north face of Mount Everest, the world's highest peak.

  16. BOREAS TGB-12 Isotropic Carbon Dioxide Data over the NSA

    NASA Technical Reports Server (NTRS)

    Trumbore, Susan; Hall, Forrest G. (Editor); Sundquist, Eric; Winston, Greg; Conrad, Sara K. (Editor)

    2000-01-01

    The BOREAS TGB-12 team made measurements of soil carbon inventories, carbon concentration in soil gases, and rates of soil respiration at several sites to estimate the rates of carbon accumulation and turnover in each of the major vegetation types. This data set contains information on the carbon isotopic content of carbon dioxide sampled from soils in the NSA-OBS, NSA-YJP, and NSA-OJP sites. Data were collected from 14-Nov-1993 to 10-Oct-1996. The data are stored in tabular ASCII files.

  17. BOREAS RSS-3 Atmospheric Measurements from a Helicopter-Mounted Sunphotometer

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G. (Editor); Nickerson, Jaime (Editor); Walthall, Charles L.; Loechel, Sara; Halthore, Rangasayi

    2000-01-01

    The BOREAS RSS-3 team collected and processed helicopter-based measurements of atmospheric conditions to estimates of aerosol optical thickness and atmospheric water vapor. The automatic sun-tracking photometer for helicopters was deployed during all three 1994 IFCs at numerous tower and auxiliary sites in both the NSA and the SSA. Six spectral channels (440, 540, 613, 670, 870, and 1030 nm) were chosen to span the visible and NIR wavelengths and to avoid gaseous absorption. One additional channel, 940 nm, was selected to measure the water column abundance above the helicopter platform. The data are stored in tabular ASCII files.

  18. BOREAS RSS-1 PARABOLA SSA Surface Reflectance and Transmittance Data

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G. (Editor); Nickeson, Jaime (Editor); Deering, Donald D.; Eck, Thomas F.; Banerjee, Babu

    2000-01-01

    The BOREAS RSS-1 team collected surface reflectance and transmittance data from three forested sites in the SSA. This data set contains averaged reflectance factors and transmitted radiances measured by the PARABOLA instrument at selected sites in the BOREAS SSA at different view angles and at three wavelength bands throughout the day. PARABOLA measurements were made during each of the three BOREAS IFCs during the growing season of 1994 at three SSA tower flux sites as well as during the FFC-T. Additional measurements were made in early and mid-1996 during the FFC-W and during IFC-2. The data are stored in tabular ASCII files.

  19. BOREAS RSS-4 1994 Southern Study Area Jack Pine LAI and FPAR Data

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G. (Editor); Nickeson, Jaime (Editor); Plummer, Stephen

    2000-01-01

    The RSS-4 team collected several data sets related to leaf, plant, and stand physical, optical, and chemical properties. This data set contains leaf area indices and FPAR measurements that were taken at the three conifer sites in the BOREAS SSA during August 1993 and at the jack pine tower flux and a subset of auxiliary sites during July and August 1994. The measurements were made with LAI-2000 and Ceptometer instruments. The measurements were taken for the purpose of model parameterization and to test empirical relationships that were hypothesized between biophysical parameters and remotely sensed data. The data are stored in tabular ASCII files.

  20. BOREAS TE-12 Incoming PAR Through the Forest Canopy Data

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G. (Editor); Papagno, Andrea (Editor); Walter-Shea, Elizabeth A.; Mesarch, Mark A.

    2000-01-01

    The Boreal Ecosystem-Atmospheric Study (BOREAS) TE-12 (Terrestrial Ecology) team collected photosynthetically active radiation (PAR) data sets in support of its efforts to characterize and interpret information on shoot geometry, leaf optical properties, leaf water potential, and leaf gas exchange. The data were collected at the Southern Study Area-Old Black Spruce (SSA-OBS) site from 04-Jul-1996 to 25-Jul-1996. 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).