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1

Composite MARC Format. A Tabular Listing of Content Designators Used in the MARC Formats.  

ERIC Educational Resources Information Center

Intended to be used for comparative purposes and in the design of generalized computer programs for systems using the MARC formats for bibliographic records, this publication contains a listing in tabular form of the content designators used in the various MARC formats. Content designators are listed under Leader, Control Fields, and Variable…

Library of Congress, Washington, DC. MARC Development Office.

2

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

USGS Publications Warehouse

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

Sanford, R. F.

1994-01-01

3

SEGY to ASCII: Conversion and Plotting Program  

USGS Publications Warehouse

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

Goldman, Mark R.

1999-01-01

4

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

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

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

2005-01-01

5

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...

6

DAWN: A Novel Strategy for Detecting ASCII Worms in Networks  

E-print Network

DAWN: A Novel Strategy for Detecting ASCII Worms in Networks Parbati Kumar Manna Sanjay Ranka detect worms in the ASCII stream due to the structural properties of the ASCII payload. In this paper, we a detection technique that would exploit those limitations. We introduce DAWN, a novel ASCII worm detection

Chen, Shigang

7

Semantic Search in Tabular Structures  

Microsoft Academic Search

The Semantic Web search aims to overcome the bottleneck of flnding relevant infor- mation using formal knowledge models, e.g. ontologies. The focus of this paper is to extend a typical search engine with semantic search over tabular structures. We cate- gorize HTML documents into topics and genres. Using the TARTAR system, tabular structures in the documents are then automatically transformed

Aleksander Pivk; Matjaz Gams; Mitja Lustrek

2006-01-01

8

SEGY to ASCII Conversion and Plotting Program 2.0  

USGS Publications Warehouse

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

Goldman, Mark R.

2005-01-01

9

A new model for tabular-type uranium deposits  

USGS Publications Warehouse

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

Sanford, R. F.

1992-01-01

10

DAWN: A Novel Strategy for Detecting ASCII Worms in Networks  

Microsoft Academic Search

While a considerable amount of research has been done for detecting the binary worms exploiting the vulnerability of buffer overflow, very little effort has been spent in detecting worms that consist of text, i.e., printable ASCII characters only. We show that the existing worm detectors often either do not examine the ASCII stream or may not be suited to efficiently

Parbati Kumar; Manna Sanjay; Ranka Shigang Chen

11

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

NASA Technical Reports Server (NTRS)

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.

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

1991-01-01

12

DAWN: A Novel Strategy for Detecting ASCII Worms in Networks  

Microsoft Academic Search

Abstract— While a considerable,amount,of research,has been done,for detecting the binary worms,exploiting the vulnerability of buffer overflow, very little effort has been spent in detecting worms that consist of text, i.e., printable ASCII characters only. We show,that the existing worm,detectors,often either do not examine,the ASCII stream,or may,not be suited to efficiently detect,the worm,in the ASCII stream,due,to the structural properties of the

Parbati K. Manna; Sanjay Ranka; Shigang Chen

2008-01-01

13

Processing genome scale tabular data with wormtable  

PubMed Central

Background Modern biological science generates a vast amount of data, the analysis of which presents a major challenge to researchers. Data are commonly represented in tables stored as plain text files and require line-by-line parsing for analysis, which is time consuming and error prone. Furthermore, there is no simple means of indexing these files so that rows containing particular values can be quickly found. Results We introduce a new data format and software library called wormtable, which provides efficient access to tabular data in Python. Wormtable stores data in a compact binary format, provides random access to rows, and enables sophisticated indexing on columns within these tables. Files written in existing formats can be easily converted to wormtable format, and we provide conversion utilities for the VCF and GTF formats. Conclusions Wormtable’s simple API allows users to process large tables orders of magnitude more quickly than is possible when parsing text. Furthermore, the indexing facilities provide efficient access to subsets of the data along with providing useful methods of summarising columns. Since third-party libraries or custom code are no longer needed to parse complex plain text formats, analysis code can also be substantially simpler as well as being uniform across different data formats. These benefits of reduced code complexity and greatly increased performance allow users much greater freedom to explore their data. PMID:24308302

2013-01-01

14

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

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).

Geological Survey (U.S.)

2006-01-01

15

Page 1 of 2 `5-Phase' EOS: A Tabular H2O EOS for Shock Physics Codes  

E-print Network

Page 1 of 2 `5-Phase' EOS: A Tabular H2O EOS for Shock Physics Codes Sarah T. Stewart Department-commercial use. 2) Users are expected to validate hydrocode calculations using the tabular EOS EOS should cite the appendix in: Senft, L. E., and S. T. Stewart. Impact Crater Formation in Icy

Stewart, Sarah T.

16

MaxiBook: UserCentered Hypertext on an ASCII Michael L. Littman  

E-print Network

MaxiBook: User­Centered Hypertext on an ASCII Terminal Michael L. Littman Bellcore Cognitive). This version (written by Michael Littman in GNU Emacs Lisp) is discussed in detail in the following section

Littman, Michael L.

17

Ontology patterns for tabular representations of biomedical knowledge on neglected tropical diseases  

PubMed Central

Motivation: Ontology-like domain knowledge is frequently published in a tabular format embedded in scientific publications. We explore the re-use of such tabular content in the process of building NTDO, an ontology of neglected tropical diseases (NTDs), where the representation of the interdependencies between hosts, pathogens and vectors plays a crucial role. Results: As a proof of concept we analyzed a tabular compilation of knowledge about pathogens, vectors and geographic locations involved in the transmission of NTDs. After a thorough ontological analysis of the domain of interest, we formulated a comprehensive design pattern, rooted in the biomedical domain upper level ontology BioTop. This pattern was implemented in a VBA script which takes cell contents of an Excel spreadsheet and transforms them into OWL-DL. After minor manual post-processing, the correctness and completeness of the ontology was tested using pre-formulated competence questions as description logics (DL) queries. The expected results could be reproduced by the ontology. The proposed approach is recommended for optimizing the acquisition of ontological domain knowledge from tabular representations. Availability and implementation: Domain examples, source code and ontology are freely available on the web at http://www.cin.ufpe.br/~ntdo. Contact: fss3@cin.ufpe.br PMID:21685092

Santana, Filipe; Schober, Daniel; Medeiros, Zulma; Freitas, Fred; Schulz, Stefan

2011-01-01

18

Starbase Data Tables: An ASCII Relational Database for Unix  

NASA Astrophysics Data System (ADS)

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.

Roll, John

2011-11-01

19

Consistent thermodynamic derivative estimates for tabular equations of state  

Microsoft Academic Search

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

Gary A. Dilts

2006-01-01

20

Revisiting Bertin Matrices: New Interactions for Crafting Tabular Visualizations  

E-print Network

Revisiting Bertin Matrices: New Interactions for Crafting Tabular Visualizations Charles Perin" by encoding cell values visually and grouping similar rows and columns. Although there were several attempts and accessible to any scientist and researcher [42]. It was based on two simple ideas: i) encoding table

Paris-Sud XI, Université de

21

Consistent thermodynamic derivative estimates for tabular equations of state  

Microsoft Academic Search

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

Gary Dilts

2005-01-01

22

Design of tabular excavations in foliated rock: an integrated numerical  

E-print Network

Design of tabular excavations in foliated rock: an integrated numerical modelling approach E techniques to investigate ground response in the near-field rock mass surrounding the mining excavations Introduction Ore recovery from underground mining involves developing excavations to gain access

23

MCNP/X TRANSPORT IN THE TABULAR REGIME  

SciTech Connect

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.

HUGHES, H. GRADY [Los Alamos National Laboratory

2007-01-08

24

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

NASA Technical Reports Server (NTRS)

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

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

1982-01-01

25

State Of The Art In Digital Steganography Focusing ASCII Text Documents  

E-print Network

Digitization of analogue signals has opened up new avenues for information hiding and the recent advancements in the telecommunication field has taken up this desire even further. From copper wire to fiber optics, technology has evolved and so are ways of covert channel communication. By "Covert" we mean "anything not meant for the purpose for which it is being used". Investigation and detection of existence of such cover channel communication has always remained a serious concern of information security professionals which has now been evolved into a motivating source of an adversary to communicate secretly in "open" without being allegedly caught or noticed. This paper presents a survey report on steganographic techniques which have been evolved over the years to hide the existence of secret information inside some cover (Text) object. The introduction of the subject is followed by the discussion which is narrowed down to the area where digital ASCII Text documents are being used as cover. Finally, the conc...

Rafat, Khan Farhan

2010-01-01

26

Consistent thermodynamic derivative estimates for tabular equations of state  

E-print Network

Numerical simulations of compressible fluid flows require an equation of state (EOS) to relate the thermodynamic variables of density, internal energy, temperature, and pressure. A valid EOS must satisfy the thermodynamic conditions of consistency (derivation from a free energy) and stability (positive sound speed squared). When phase transitions are significant, the EOS is complicated and can only be specified in a table. For tabular EOS's such as SESAME from Los Alamos National Laboratory, the consistency and stability conditions take the form of a differential equation relating the derivatives of pressure and energy as functions of temperature and density, along with positivity constraints. Typical software interfaces to such tables 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. We describe a new type of table interface based on a constrained local least squar...

Dilts, G A

2005-01-01

27

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

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.

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

2007-01-01

28

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

NASA Technical Reports Server (NTRS)

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.

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

2001-01-01

29

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

NASA Technical Reports Server (NTRS)

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.

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

2002-01-01

30

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

USGS Publications Warehouse

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

Trippi, Michael H.; Crangle, Robert D., Jr.

2009-01-01

31

Summer Decay Processes in a Large Tabular Iceberg  

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

32

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

Microsoft Academic Search

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

James E. Quick

1982-01-01

33

ICESat profiles of tabular iceberg margins and iceberg breakup at low Ted Scambos,1  

E-print Network

ICESat profiles of tabular iceberg margins and iceberg breakup at low latitudes Ted Scambos,1 Olga of tabular iceberg margins and the Ronne Ice Shelf edge reveal shapes indicative of two types of bending forces. Icebergs and shelf fronts in sea-ice-covered areas have broad ($1000 m wide), rounded, $0.6 m

Boyce, C. Kevin

34

Calving of large tabular icebergs from ice shelf rift systems Ian Joughin1,2  

E-print Network

Calving of large tabular icebergs from ice shelf rift systems Ian Joughin1,2 and Douglas R. Mac large icebergs to calve from the Ross Ice Shelf, Antarctica. Time series of rift geometries indicate geometry. Both the observations and model suggest that rift opening, and, thus, tabular-iceberg calving

Boyce, C. Kevin

35

Consistent thermodynamic derivative estimates for tabular equations of state  

NASA Astrophysics Data System (ADS)

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.

Dilts, Gary A.

2006-06-01

36

Consistent thermodynamic derivative estimates for tabular equations of state.  

NASA Astrophysics Data System (ADS)

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.

Dilts, Gary

2005-07-01

37

Consistent thermodynamic derivative estimates for tabular equations of state.  

PubMed

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. PMID:16907020

Dilts, Gary A

2006-06-01

38

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

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).

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

2006-01-01

39

Deriving tabular event-based specifications from goal-oriented requirements models  

Microsoft Academic Search

Goal-oriented methods are increasingly popular for elaborating software requirements. They offer systematic support for incrementally building intentional, structural and operational models of the software and its environment. They also provide various techniques for early analysis, notably, to manage conflicting goals or to anticipate abnormal environment behaviours that prevent goals from being achieved. On the other hand, tabular event-based methods are

Renaud De Landtsheer; Emmanuel Letier

2004-01-01

40

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

E-print Network

Tracking large tabular icebergs using the SeaWinds Ku-band microwave scatterometer K.M. Stuart Ã?, D Resolution enhancement Icebergs Sea ice NSF Antarctic cruise a b s t r a c t Knowledge of iceberg locations icebergs scatter microwave energy more than sea ice and sea water, icebergs are detected as high

Long, David G.

41

Using visual cues for extraction of tabular data from arbitrary HTML documents  

Microsoft Academic Search

We describe a method to extract tabular data from web pages. Rather than just analyzing the DOM tree, we also exploit visual cues in the rendered version of the document to extract data from tables which are not explicitly marked with an HTML table element. To detect tables, we rely on a variant of the well-known X-Y cut algorithm as

Bernhard Krüpl; Marcus Herzog; Wolfgang Gatterbauer

2005-01-01

42

LARGE TABULAR ICEBERGS AND ICE ISLANDS OFF EASTERN CANADA IN 2001-2003 AND THEIR PROBABLE SOURCE  

Microsoft Academic Search

In 2002 and 2003, offshore operators on the Grand Banks reported an unusually large number of ice islands and large tabular icebergs up to 20 million tonnes, with drafts of 65 to 80m. This paper describes sightings of large tabular icebergs and ice islands in 2001 to 2003 north of the Grand Banks, from Lancaster Sound in the Canadian Arctic

I. K. Peterson

43

Time-dependent Behaviour of Deep Level Tabular Excavations in Hard Rock  

Microsoft Academic Search

Summary   Although hard rock is not usually associated with large creep deformation, significant time-dependent behaviour is observed\\u000a in the tabular excavations of the South African gold mines. Time-dependent closure data was collected in stopes of the Ventersdorp\\u000a Contact Reef and Vaal Reef. This data typically consists of a primary closure phase after blasting, followed by a steady-state\\u000a closure phase. This

D. F. Malan

1999-01-01

44

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

NASA Astrophysics Data System (ADS)

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.

Quick, James E.

1982-03-01

45

Use of an Audit Program to Improve Confidentiality Protection of Tabular Data at the Bureau of Labor Statistics.  

National Technical Information Service (NTIS)

U.S. Statistical Agencies develop disclosure avoidance processes to ensure that individually identifiable data can not be detected in the published tabular tables from confidential data. The Disclosure Audit System (DAS) is software that uses linear progr...

R. Powers, S. Cohen

2008-01-01

46

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

NASA Astrophysics Data System (ADS)

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

Wadhams, P.

2013-12-01

47

A Simple Tool for Integration and Differentiation of Tabular Values in Microsoft Excel  

NASA Astrophysics Data System (ADS)

There are many software alternatives for analyzing experimental data in our physics teaching. I prefer to use Excel® because of its flexibility and widespread use elsewhere in our society. Whatever our students will work with in their future career, they almost certainly will have access to a spreadsheet. For a long time I have missed a tool for integrating and differentiating tabular values in Excel. For every new version I thought it would appear, but it did not. Such a tool could also be useful if you analyze data from other sources than your own experiment, for example, data from the Internet. Therefore, I have written a simple tool that can be integrated seamlessly into Excel as an add-in. It is written in Excels powerful macro language Microsoft Visual Basic for Applications. The tool can be downloaded online and there are two versions of it: one for Excel 2003 and one for Excel 2007/2010.

Haugland, Ole Anton

2011-12-01

48

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

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).

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

2006-01-01

49

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

SciTech Connect

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

Carpenter, John H.; Belcourt, Noel

2013-04-01

50

Effects of Rigid Body Collisions and Tide-Forced Drift on Large Tabular Icebergs of the Antarctic  

E-print Network

1 Effects of Rigid Body Collisions and Tide-Forced Drift on Large Tabular Icebergs of the Antarctic ICEBERGS #12;2 Abstract. Following the calving of an iceberg from an ice shelf, many collisions between the new iceberg and the remaining shelf can occur as the iceberg responds to time-varying oceanic

Macayeal, Douglas R.

51

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

Microsoft Academic Search

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

Ramana Rao; Stuart K. Card

1994-01-01

52

Algorithms for Hyperspectral Signature Classification in Non-resolved Object Characterization Using Tabular Nearest Neighbor Encoding  

NASA Astrophysics Data System (ADS)

Accurate spectral signature classification is key to the nonimaging detection and recognition of spaceborne objects. In classical hyperspectral recognition applications, signature classification accuracy depends on accurate spectral endmember determination [1]. However, in selected target recognition (ATR) applications, it is possible to circumvent the endmember detection problem by employing a Bayesian classifier. Previous approaches to Bayesian classification of spectral signatures have been rule- based, or predicated on a priori parameterized information obtained from offline training, as in the case of neural networks [1,2]. Unfortunately, class separation and classifier refinement results in these methods tends to be suboptimal, and the number of signatures that can be accurately classified often depends linearly on the number of inputs. This can lead to potentially significant classification errors in the presence of noise or densely interleaved signatures. In this paper, we present an emerging technology for nonimaging spectral signature classfication based on a highly accurate but computationally efficient search engine called Tabular Nearest Neighbor Encoding (TNE) [3]. Based on prior results, TNE can optimize its classifier performance to track input nonergodicities, as well as yield measures of confidence or caution for evaluation of classification results. Unlike neural networks, TNE does not have a hidden intermediate data structure (e.g., the neural net weight matrix). Instead, TNE generates and exploits a user-accessible data structure called the agreement map (AM), which can be manipulated by Boolean logic operations to effect accurate classifier refinement algorithms. This allows the TNE programmer or user to determine parameters for classification accuracy, and to mathematically analyze the signatures for which TNE did not obtain classification matches. This dual approach to analysis (i.e., correct vs. incorrect classification) has been shown to significantly strengthen analysis of classifier performance in support of classifier optimization. We show that AM-based classification can be modified to include dynamic tracking of input statistical changes, to achieve accurate signature classification in the presence of noise, closely spaced or interleaved signatures, and simulated optical distortions. In particular, we examine two critical cases: (1) classification of multiple closely spaced signatures that are difficult to separate using distance measures, and (2) classification of materials in simulated hyperspectral images of spaceborne satellites. In each case, test data are derived from a NASA database of space material signatures. Additional analysis pertains to computational complexity and noise sensitivity, which are superior to Bayesian techniques based on classical neural networks.

Schmalz, M.; Key, G.

53

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

SciTech Connect

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

Hazen, T.C. [Westinghouse Savannah River Co., Aiken, SC (United States)

1993-09-01

54

Three dimensional characterization and capture zone analysis of a dipping tabular fractured bedrock aquifer  

Microsoft Academic Search

In order to improve the effectiveness of an existing groundwater recovery and treatment system at a manufacturing site in eastern Pennsylvania, an analysis of groundwater flow within fractured bedrock of the Triassic Brunswick Formation was conducted using water quality, lithologic and hydrologic data, compiled at the site over a period of 13 years. Groundwater quality data, collected from on-site monitoring

1993-01-01

55

A PCM\\/VCR speech database exchange format  

Microsoft Academic Search

The use of PCM\\/VCR technology is described for use as a storage and exchange medium for speech databases. In order to provide a limited amount of digital data, use is made of a recorded modem signal for ASCII character string headers associated with the speech tokens. This format can be used to store field recordings of speech material for subsequent

David S. Pallett

1986-01-01

56

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)

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.

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

2010-05-01

57

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

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…

Peng, Samuel S.; And Others

58

Martin et al., Iceberg Interactions at Cape Adare 1 Kinematic and Seismic Analysis of Giant Tabular Iceberg Breakup at Cape Adare,  

E-print Network

Martin et al., Iceberg Interactions at Cape Adare 1 Kinematic and Seismic Analysis of Giant Tabular Iceberg Breakup at Cape Adare, Antarctica Seelye Martin1 , Robert Drucker1 , Richard Aster2 , Fred Davey3 60637, USA Short Title: Iceberg Interactions at Cape Adare POST-REVIEW REVISION Thursday, 21 January

Boyce, C. Kevin

59

The SmOKe music representation, description language, and interchange format  

Microsoft Academic Search

The Smallmusic Object Kernel (SmOKe) is an object-oriented representation, description language and interchange format for musical parameters, events, and structures. The author believes this representation, and its proposed linear ASCII description, to be well-suited as a basis for: (1) concrete description interfaces in other languages, (2) specially-designed binary storage and interchange formats, and (3) use within and between interactive multimedia,

Stephen Travis Pope

60

Verification of model simulated mass balance, flow fields and tabular calving events of the Antarctic ice sheet against remotely sensed observations  

NASA Astrophysics Data System (ADS)

The Antarctic ice sheet (AIS) has the greatest potential for global sea level rise. This study simulates AIS ice creeping, sliding, tabular calving, and estimates the total mass balances, using a recently developed, advanced ice dynamics model, known as SEGMENT-Ice. SEGMENT-Ice is written in a spherical Earth coordinate system. Because the AIS contains the South Pole, a projection transfer is performed to displace the pole outside of the simulation domain. The AIS also has complex ice-water-granular material-bedrock configurations, requiring sophisticated lateral and basal boundary conditions. Because of the prevalence of ice shelves, a `girder yield' type calving scheme is activated. The simulations of present surface ice flow velocities compare favorably with InSAR measurements, for various ice-water-bedrock configurations. The estimated ice mass loss rate during 2003-2009 agrees with GRACE measurements and provides more spatial details not represented by the latter. The model estimated calving frequencies of the peripheral ice shelves from 1996 (roughly when the 5-km digital elevation and thickness data for the shelves were collected) to 2009 compare well with archived scatterometer images. SEGMENT-Ice's unique, non-local systematic calving scheme is found to be relevant for tabular calving. However, the exact timing of calving and of iceberg sizes cannot be simulated accurately at present. A projection of the future mass change of the AIS is made, with SEGMENT-Ice forced by atmospheric conditions from three different coupled general circulation models. The entire AIS is estimated to be losing mass steadily at a rate of ~120 km3/a at present and this rate possibly may double by year 2100.

Ren, Diandong; Leslie, Lance M.; Lynch, Mervyn J.

2013-06-01

61

Directory interchange format manual, version 3.0  

NASA Technical Reports Server (NTRS)

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.

1990-01-01

62

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

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

63

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

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…

Peng, Samuel S.; Holt, Mary M.

64

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

NASA Astrophysics Data System (ADS)

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.

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

2012-04-01

65

Testing the apatite-magnetite geochronometer: U-Pb and 40Ar/ 39Ar geochronology of plutonic rocks, massive magnetite-apatite tabular bodies, and IOCG mineralization in Northern Chile  

NASA Astrophysics Data System (ADS)

Detailed zircon and apatite U-Pb dating and 40Ar/ 39Ar dating of actinolite have been carried out on the Carmen-Sierra Aspera Kiruna type magnetite-apatite and iron oxide Cu-Au (IOCG) district in the Coastal Cordillera of northern Chile (˜26°S). They define a precise succession of magmatic and hydrothermal events associated with early Cretaceous Andean magmatism. Apatite and magnetite from a magnetite-apatite tabular body with intergrowth texture in the Carmen deposit yield a total Pb-U isochron age of 131.0 ± 1.0 Ma. This result is the first direct dating of magnetite-apatite mineralization in an early Andean deposit, and the age coincides with zircon ages of a quartz diorite stock that partially hosts mineralization (130.6 ± 0.3 Ma). Magnetite from the studied tabular body contains only small amounts of radiogenic Pb and serves to constrain the initial common Pb isotopic composition. The high degree of correlation suggests that both minerals closed for Pb diffusion at essentially the same time and at a relatively high temperature (close to that of zircon), making the apatite-magnetite pair a reliable geochronometer for igneous or hydrothermal crystallization. Zircon from the Sierra Aspera composite pluton yields ages between 131.3 ± 0.3 Ma and 127.4 ± 0.1 Ma, clearly resolving the timing of intrusion of discrete intrusive phases. Actinolite 40Ar/ 39Ar ages partially overlap the ages of plutonic phases of the Sierra Aspera pluton, but are younger than the magnetite-apatite tabular body. The initial Pb isotopic composition of the melts and/or fluids from which the magnetite-apatite tabular bodies crystallized is very similar to the primitive Pb isotopic composition of granitic magmas associated with early Cretaceous plutons measured in K-feldspar. The Pb isotopic correspondence, combined with the temporal and spatial association between magnetite-apatite mineralization and the dioritic-quartz dioritic magmatism, strongly suggests a genetic relationship between early Cretaceous continental arc magmatism, massive magnetite-apatite deposits, and IOCG mineralization.

Gelcich, Sergio; Davis, Donald W.; Spooner, Edward T. C.

2005-07-01

66

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)

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)

Siegel, Carl Ludwig; Carl-Ludwig Siegel, Edward

2011-03-01

67

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.

68

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

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).

Wieczorek, Michael E.; LaMotte, Andrew E.

2010-01-01

69

Directory interchange format manual, version 4.0  

NASA Technical Reports Server (NTRS)

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.

1991-01-01

70

Tabular equation of state for gold  

NASA Astrophysics Data System (ADS)

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

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

2012-03-01

71

Tabular Equation of State for Gold  

NASA Astrophysics Data System (ADS)

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

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

2011-06-01

72

Delayed beta- and gamma-ray production due to thermal-neutron fission of /sup 239/Pu: tabular and graphical spectral distributions for times after fission between 2 and 14000 sec  

SciTech Connect

Fission-product decay energy-release rates were measured for thermal-neutron fission of /sup 239/Pu. Samples of mass 1 and 5 ..mu..g were irradiated for 1 to 100 s using the fast pneumatic-tube facility at the Oak Ridge Research Reactor. The resulting beta- and gamma-ray emissions were separately counted for times-after-fission between 2 and 14,000 s to yield spectral distributions N(E/sub ..gamma../) vs E/sub ..gamma../ and N(E/sub ..beta../) vs E/sub ..beta../. The gamma-ray spectra were obtained by use of a NaI detector, and the beta-ray spectra were obtained by use of an NE-110 detector with an anticoincidence mantle. The raw data were unfolded to provide spectral distributions of moderate resolution. These distributions are given in graphical and tabular form as differential spectral intensity I(E) (MeV/sup -1/ fission/sup -1/) averaged over gamma-ray energy intervals ranging from 10 keV for E/sub ..gamma../ < 0.18 MeV to 100 keV for E/sub ..gamma../ > 6.8 MeV, and beta-ray energy intervals ranging from 20 keV for E/sub ..beta../ < 0.25 MeV to 160 keV for E/sub ..beta../ > 6.4 MeV. Counting-time intervals ranged from 1 s for times-after-fission (t/sub w/) < 6 s to 4000 s for t/sub w/ approx. 10/sup 4/ s. For comparisons the graphical representations show calculated spectra obtained by use of the CINDER-10 summation code and the ENDF/B-IV fission yield and decay scheme data base. 90 figures, 86 tables.

Dickens, J.K.; England, T.R.; Love, T.A.; McConnell, J.W.; Emergy, J.F.; Northcutt, K.J.; Peelle, R.W.

1980-01-01

73

BOREAS TF-9 SSA-OBS Branch Level Flux Data  

NASA Technical Reports Server (NTRS)

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.

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

2000-01-01

74

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

NASA Technical Reports Server (NTRS)

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.

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

2000-01-01

75

Rectangular subsonic jet flow field measurements  

NASA Technical Reports Server (NTRS)

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.

Morrison, Gerald L.; Swan, David H.

1989-01-01

76

Planet formation  

Microsoft Academic Search

Models of planetary formation are developed using the present single example of a planetary system, supplemented by limited astrophysical observations of star-forming regions and circumstellar disks. The solar nebula theory and the planetesimal hypothesis are discussed. The latter is found to provide a viable theory of the growth of the terrestrial planets, the cores of the giant planets, and the

Jack J. Lissauer

1993-01-01

77

Internal structure and environmental reconstruction of eocene transitional fan-delta deposits, monllobat-castigaleu formations, Southern Pyrenees, Spain  

NASA Astrophysics Data System (ADS)

A detailed study has been made of a part (500 × 200 × 15 m) of the Eocene Monllobat Formation. The conglomeratic bottomset—foreset—topset build up of a small fan-delta passes into sand- and mudstone layers. Ultimately the sandstone layers wedge into the mudstone due to concave-upwards basal surfaces and convex top surfaces or due to thickening of intercalated mud layers. Sequences vary accordingly from coarsening upwards in the proximal parts to fining upwards distally. Both sequences are topped by a thin layer fining upwards. The proximal fan-deltaic part consists of interconnected lobes. Crescentic, transverse bars deposited gravel on a slightly inclined top. Conglomerates of the moderately inclined foreset show some imbrication. The bottomset consists of tabular cross-bedded and cross-laminated sandstone. Parallel-laminated and tabular cross-bedded sandstone layers drape rises of fine sediment in front of the fan-delta face. Continued progradation brought about truncation of these backset sediments. Sandstone lobes of the distal part are not connected. Tabular croos-bedding and parallel lamination are the main sedimentary structures. Climbing, large-scale bedforms are prominent on top surfaces. Most of the lobes are enveloped by blue-grey mud. Layers covered by mottled mud terminate in foreset faces. Highly energetic inflow took place from a shallow, braided stream with longitudinal bars. The low sedimentary relief caused jetflow. The high flow energy, the large grain-size range and the large quantities of sediment caused great differences from inflow models for the deltaic environment. Sedimentation was effected by flow deceleration. Expansion, inertial forces, friction or a combination of these phenomena were responsible for the deceleration. Expansion and inertial forces caused development of moderately inclined foreset faces. Due to expansion, steeply inclined foresets were formed. Sand was deposited in shallow marine water and in scour pits in continental deposits during flow deceleration caused by frictional and inertial forces. Parallel-laminated backsets connected with flat, tabular sets developed due to flow deceleration by expansion and frictional forces. The deposits were formed in the transition zone of a fan-delta under a tropical climate with marked dry and wet periods. Wide, braided streams entered a restricted, shallow marine basin at right angles to the basin axis. Aggradation exceeded water depth. Progradation processes were influenced by large- and small-scale tectonic activity.

Meulen, Sjoerd Van Der

1983-12-01

78

Galaxy formation  

PubMed Central

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

Peebles, P. J. E.

1998-01-01

79

ANTIBODY FORMATION  

PubMed Central

The suppression of antibody formation by passively administered antibody is influenced by the dose and nature of the antigen, type of immunization procedure, ratio of antibody to antigen, species origin and characteristics of the antiserum used, as well as the species selected for immunization. In guinea pigs, diphtheria antitoxin formation can be effectively suppressed by an intravenous injection of excess homologous or heterologous antitoxin as long as 5 days after toxoid immunization and after delayed-type hypersensitivity to toxoid has developed. Following the period of antibody suppression which lasts 2 to 7 weeks, serum antibody can usually be demonstrated. It is proposed that this delayed immunization results from dissociation of antigen, since diphtheritic paralysis and death can be produced in guinea pigs and rabbits by the intravenous injection of toxin-antitoxin precipitates formed in antitoxin excess. This syndrome is prevented by injection of excess horse antitoxin 1 hour after injection of the toxin-antitoxin complexes. PMID:13779027

Uhr, Jonathan W.; Baumann, Joyce B.

1961-01-01

80

Cloud Formation  

NASA Astrophysics Data System (ADS)

Cloud formation is crucial to the heritage of modern physics, and there is a rich literature on this important topic. In 1927, Charles T.R. Wilson was awarded the Nobel Prize in physics for applications of the cloud chamber.2 Wilson was inspired to study cloud formation after working at a meteorological observatory on top of the highest mountain in Scotland, Ben Nevis, and testified near the end of his life, "The whole of my scientific work undoubtedly developed from the experiments I was led to make by what I saw during my fortnight on Ben Nevis in September 1894."3 To form clouds, Wilson used the sudden expansion of humid air.4 Any structure the cloud may have is spoiled by turbulence in the sudden expansion, but in 1912 Wilson got ion tracks to show up by using strobe photography of the chamber immediately upon expansion.5 In the interim, Millikan's study in 1909 of the formation of cloud droplets around individual ions was the first in which the electron charge was isolated. This study led to his famous oil drop experiment.6 To Millikan, as to Wilson, meteorology and physics were professionally indistinct. With his meteorological physics expertise, in WWI Millikan commanded perhaps the first meteorological observation and forecasting team essential to military operation in history.7 But even during peacetime meteorology is so much of a concern to everyone that a regular news segment is dedicated to it. Weather is the universal conversation topic, and life on land could not exist as we know it without clouds. One wonders then, why cloud formation is never covered in physics texts.

Graham, Mark Talmage

2004-05-01

81

Fossil formation  

NSDL National Science Digital Library

The National Science Education Standards Life Science Content Standard mentions that fossils indicate extinct species and contribute to an understanding of evolution and diversity. The Earth and Space Sciences Content Standard tells us they provide clues about past environments. But what is a fossil? How does it form? The processes can be complex. An understanding of fossil formation will enable accurate student conceptions of related science concepts including methods of science in geology, paleontology, and evolution.

University, Staff A.

2008-03-07

82

Pattern formation in magma dynamics: The oscillatory instability  

NASA Astrophysics Data System (ADS)

The extraction of partial melt from planetary interiors is the key mechanism that links surface observations to the structure and processes in the interior. Outcrops of mantle materials (ophiolites) show a striking tabular or channel-like pattern of almost pure dunite imbedded in residual harzburgite and lherzolite matrices. Viscous deformation of the solid matrix and the reactive porous flow of the buoyant melt may give rise to instabilities that lead to the formation of channel-like patterns. We present an extended physicochemical hydrodynamic model that explicitly computes the chemical depletion of the solid matrix as well as the chemical and mechanic interactions between the deforming matrix and the reacting melt. We present linear stability results and high-resolution high-accuracy numerical simulations. Two distinct types of instability are observed: a channeling instability similar to that reported by Aharonov et al. (1995) and a new oscillatory or wave-like instability. The oscillatory instability leads to dynamic checkerboard patterns in the melt fraction (porosity) and compaction rate that migrate upwards in the upwelling column. The numerical simulations show progressive chemical depletion along the vertical nodal lines of the checkerboard pattern and may offer an alternative explanation for the formation of the dunite channels. A parameter study suggests that the oscillatory instability may play an important role for melt migration beneath the mid-ocean ridge. references: Aharonov, E., J. Whitehead, P. Kelemen, and M. Spiegelman (1995), Channeling instability of upwelling melt in the mantle, J. Geophys. Res., 100(B10), 20433-20450.

Hesse, M. A.; Schiemenz, A.; Liang, Y.; Parmentier, E.

2009-12-01

83

P Formation  

NASA Astrophysics Data System (ADS)

The voids formed in the Ni3P layer during reaction between Sn-based solders and electroless Ni-P metallization is an important cause of rapid degradation of solder joint reliability. In this study, to suppress formation of the Ni3P phase, an electrolessly plated Ni-Sn-P alloy (6-7 wt.% P and 19-21 wt.% Sn) was developed to replace Ni-P. The interfacial microstructure of electroless Ni-Sn-P/Sn-3.5Ag solder joints was investigated after reflow and solid-state aging. For comparison, the interfacial reaction in electroless Ni-P/Sn-3.5Ag solder joints under the same reflow and aging conditions was studied. It was found that the Ni-Sn-P metallization is consumed much more slowly than the Ni-P metallization during soldering. After prolonged reaction, no Ni3P or voids are observed under SEM at the Ni-Sn-P/Sn-3.5Ag interface. Two main intermetallic compounds, Ni3Sn4 and Ni13Sn8P3, are formed during the soldering reaction. The reason for Ni3P phase suppression and the overall mechanisms of reaction at the Ni-Sn-P/Sn-3.5Ag interface are discussed.

Yang, Ying; Balaraju, J. N.; Huang, Yizhong; Tay, Yee Yan; Shen, Yiqiang; Tsakadze, Zviad; Chen, Zhong

2014-11-01

84

Pattern Formation  

NASA Astrophysics Data System (ADS)

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

Hoyle, Rebecca

2006-03-01

85

Consistent thermodynamic derivative estimates for tabular equations of state  

Microsoft Academic Search

Numerical simulations of compressible fluid flows require an equation of\\u000astate (EOS) to relate the thermodynamic variables of density, internal energy,\\u000atemperature, and pressure. A valid EOS must satisfy the thermodynamic\\u000aconditions of consistency (derivation from a free energy) and stability\\u000a(positive sound speed squared). When phase transitions are significant, the EOS\\u000ais complicated and can only be specified in

Gary A. Dilts

2006-01-01

86

MHD simulations of MTF implosions with tabular EOS and conductivities  

Microsoft Academic Search

Magnetized target fusion (MTF) is a pulsed approach that compresses magnetized fuel to achieving burning hydrogen plasma conditions. The compression in one MTF-scenario comes from uses a conducting liner that is imploded due to the action of high electrical currents that flow on the outer surface of the liner. This implosion compresses and heats a dense, warm magnetized deuterium or

R. J. Faehl; W. L. Atchison; I. R. Lindemuth

2003-01-01

87

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

E-print Network

of up to 2,400,000 continuous variables, 100,000 binary variables, and 475,000 ... safe dissemination of European business and animal production statistics by ..... Two strategies have been tested, which can be viewed as a framework whose

2010-11-05

88

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

NASA Technical Reports Server (NTRS)

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.

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

2000-01-01

89

The Format War.  

ERIC Educational Resources Information Center

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)

Kreamer, Jean

1992-01-01

90

ASCII based transcription systems for languages with the Arabic script: the case of Persian  

Microsoft Academic Search

We discuss transcription systems needed for automated spoken language processing applications in languages such as Persian that use the Arabic script for writing. The work is described in the context of a speech-to-speech translation system development for English and Persian. This system can easily be modified for Arabic, Dari, Urdu and any other language that uses the Arabic script. The

Shadi Ganjavi; Panayiotis G. Georgiou; Shrikanth Narayanan

2003-01-01

91

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

E-print Network

Committee of the Higher Education Funding Councils LaTEX MFM Magnetic Force Microscopy MIDI Musical Republic GIS Geographical Information System HEI Higher Education Institution HEFC Higher Education Funding

Carr, Leslie

92

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

E-print Network

): No changes IOP type: Single UWKA flight IOP Double flight IOP Single-generator, single-flight IOP Blowing Snow IOP Surface instrument only IOP (WWMPP IOP) Weather: Westerly flow until16 UTC, then easterly

93

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

E-print Network

). IOP type: Single UWKA flight IOP Double flight IOP Single-generator, single-flight IOP Blowing Snow occurred until ~21 UTC, at which point the snow continued light through the end of the IOP. Temperatures

94

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

E-print Network

. IOP type: Single UWKA flight IOP Double flight IOP Single-generator, single-flight IOP Blowing Snow degrees at IOP start. Extremely windy, with a gust to 94 mph (DOW, 5 m AGL). Considerable blowing and drifting snow. No SLW and a pocket of ~50% RH at 800 m AGL seen in radiometer data (2300 UTC). 0015 UTC

95

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

E-print Network

flight IOP Double flight IOP Single-generator, single-flight IOP Blowing Snow IOP Surface instrument only reflectivity above 1500 m AGL during entire IOP. Little if any snow observed. Default Deployment Strategy: Time

96

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

E-print Network

flight IOP Double flight IOP Single-generator, single-flight IOP Blowing Snow IOP Surface instrument only IOP (WWMPP IOP) Weather: Moderate to heavy snow with occasional graupel/snow pellets from IOP start, and then resumed as light snow. Snow became heavier and flakes were quite large by the end of the IOP at 1900 UTC

97

The Influence of ASCII on the Construction of Internet-Based Knowledge  

Microsoft Academic Search

The intention of this chapter is to engage the deep structures of the hegemony of the digital technology revolution as represented\\u000a by the internet, levels beneath those addressed by most of the contemporary critical discourses. I am not working with more\\u000a obvious barriers that constitute the “digital divide” such as the relationship of access to safe drinking water and basic

Jason Nolan

98

mmView: a web-based viewer of the mmCIF format  

PubMed Central

Background Structural biomolecular data are commonly stored in the PDB format. The PDB format is widely supported by software vendors because of its simplicity and readability. However, the PDB format cannot fully address many informatics challenges related to the growing amount of structural data. To overcome the limitations of the PDB format, a new textual format mmCIF was released in June 1997 in its version 1.0. mmCIF provides extra information which has the advantage of being in a computer readable form. However, this advantage becomes a disadvantage if a human must read and understand the stored data. While software tools exist to help to prepare mmCIF files, the number of available systems simplifying the comprehension and interpretation of the mmCIF files is limited. Findings In this paper we present mmView - a cross-platform web-based application that allows to explore comfortably the structural data of biomacromolecules stored in the mmCIF format. The mmCIF categories can be easily browsed in a tree-like structure, and the corresponding data are presented in a well arranged tabular form. The application also allows to display and investigate biomolecular structures via an integrated Java application Jmol. Conclusions The mmView software system is primarily intended for educational purposes, but it can also serve as a useful research tool. The mmView application is offered in two flavors: as an open-source stand-alone application (available from http://sourceforge.net/projects/mmview) that can be installed on the user's computer, and as a publicly available web server. PMID:21486459

2011-01-01

99

Star formation - An overview  

NASA Technical Reports Server (NTRS)

Methods for studying star formation are reviewed. Stellar clusters and associations, as well as field stars, provide a fossil record of the star formation process. Regions of current star formation provide a series of snapshots of different epochs of star formation. A simplified picture of individual star formation as it was envisioned in the late 1970s is contrasted with the results of recent observations, in particular the outflow phenomenon.

Evans, N. J., II

1985-01-01

100

Fluvial facies architecture in small-scale river systems in the Upper Dupi Tila Formation, northeast Bengal Basin, Bangladesh  

NASA Astrophysics Data System (ADS)

The late stage basin-fill history of the fluvial Dupi Tila Group (Plio-Pleistocene) is described. These rocks have been deposited in the Sylhet trough, a sub-basin of the Bengal Basin, in a foreland basin setting. This outcrop study, carried out in Sylhet, Bangladesh, presents the first detailed facies analysis of the Upper Dupi Tila Formation. Four facies have been identified: trough cross-bedded sandstone (St), ripple cross-laminated sandstone (Sr), finely laminated mud with ripples (Fl), and massive mud with rootlets (Fm). Facies analysis supplemented with embedded Markov chain analysis, reveals small-scale fining-upward cycles (average 4.5 m thick). Facies architectural elements include channel (CH), lateral accretion (LA), sandy bedforms (SB), and overbank fines (OF) with limited vertical and lateral connectivity of the sand bodies. The average channel depth and width is 5 and 30 m, respectively. Sand body geometry ranges from tabular, to sheet, to shoestring with a 0.45 net to gross ratio. This study shows that the Upper Dupi Tila Formation is composed of small-scale, mudstone-reach meandering river deposits. In Bangladesh, the Dupi Tila Formation is the main aquifer presently being utilized. Understanding of facies architecture and sand body geometry of this Formation is crucial in examining the issue of arsenic and other contaminations of ground water in Bangladesh.

Royhan Gani, M.; Mustafa Alam, M.

2004-11-01

101

Capital Punishment 1997  

NSDL National Science Digital Library

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.

1999-01-01

102

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

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.

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

1983-01-01

103

Scenarios for galaxy formation  

NASA Technical Reports Server (NTRS)

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.

Silk, Joseph

1997-01-01

104

Medical image file formats.  

PubMed

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

Larobina, Michele; Murino, Loredana

2014-04-01

105

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

NASA Astrophysics Data System (ADS)

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

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

1999-10-01

106

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

PubMed Central

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

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

2014-01-01

107

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

PubMed

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

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

108

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

NASA Technical Reports Server (NTRS)

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.

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

2000-01-01

109

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

NASA Technical Reports Server (NTRS)

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

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

2000-01-01

110

BOREAS RSS-2 Extracted Reflectance Factors Derived from ASAS Imagery  

NASA Technical Reports Server (NTRS)

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.

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

111

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

NASA Technical Reports Server (NTRS)

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.

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

2000-01-01

112

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

NASA Technical Reports Server (NTRS)

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

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

2000-01-01

113

BOREAS TGB-10 Volatile Organic Carbon Data over the SSA  

NASA Technical Reports Server (NTRS)

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.

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

2000-01-01

114

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

NASA Technical Reports Server (NTRS)

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.

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

2000-01-01

115

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

NASA Technical Reports Server (NTRS)

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.

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

2000-01-01

116

Planet formation in Binaries  

E-print Network

Spurred by the discovery of numerous exoplanets in multiple systems, binaries have become in recent years one of the main topics in planet formation research. Numerous studies have investigated to what extent the presence of a stellar companion can affect the planet formation process. Such studies have implications that can reach beyond the sole context of binaries, as they allow to test certain aspects of the planet formation scenario by submitting them to extreme environments. We review here the current understanding on this complex problem. We show in particular how each of the different stages of the planet-formation process is affected differently by binary perturbations. We focus especially on the intermediate stage of kilometre-sized planetesimal accretion, which has proven to be the most sensitive to binarity and for which the presence of some exoplanets observed in tight binaries is difficult to explain by in-situ formation following the "standard" planet-formation scenario. Some tentative solutions ...

Thebault, Ph

2014-01-01

117

Galaxy Formation and Evolution  

NASA Astrophysics Data System (ADS)

1. Introduction; 2. Observational facts; 3. Cosmological background; 4. Cosmological perturbations; 5. Gravitational collapse and collisionless dynamics; 6. Probing the cosmic density field; 7. Formation and structure of dark matter halos; 8. Formation and evolution of gaseous halos; 9. Star formation in galaxies; 10. Stellar populations and chemical evolution; 11. Disk galaxies; 12. Galaxy interactions and transformations; 13. Elliptical galaxies; 14. Active galaxies; 15. Statistical properties of the galaxy population; 16. The intergalactic medium; Appendices; References; Index.

Mo, Houjun; van den Bosch, Frank C.; White, Simon

2010-05-01

118

GLOBAL STAR FORMATION REVISITED  

SciTech Connect

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.

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

119

Formative Assessment Probes  

ERIC Educational Resources Information Center

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…

Eberle, Francis; Keeley, Page

2008-01-01

120

Analysis of bird formations  

Microsoft Academic Search

Birds in V formations are frequently observed and two main hypotheses have emerged in the biology\\/ornithology literature to explain this particular geometry: (i) it offers aerodynamic advantages and (ii) it is used to improve visual communication. Both explanations require a bird to track its predecessor. Observations of flocks suggest that this task is difficult for birds in large formations. We

Pete Seiler; Aniruddha Pant; Karl Hedrick

2002-01-01

121

Formative Evaluation Alternatives.  

ERIC Educational Resources Information Center

Discussion of formative evaluation highlights alternative formative evaluation methods and tools and explains their advantages, disadvantages, and applicable contexts. Methods described include two-on-one evaluation; think-aloud protocols; computer interviewing; self-evaluation; panel reviews; evaluation meetings; computer journals and networks;…

Tessmer, Martin

1994-01-01

122

Void formation in glasses  

Microsoft Academic Search

Void formation as a result of a single tightly focused femtosecond pulse irradiation has been systematically studied in commercial optical-grade glasses of different composition. Correlations between the composition, mass density, glass transition temperature and Young modulus of glass with the void formation threshold have been revealed. The pulse energy necessary to form a void was found reciprocal to the amount

Tomohiro Hashimoto; Saulius Juodkazis; Hiroaki Misawa

2007-01-01

123

School Formative Feedback Systems  

ERIC Educational Resources Information Center

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…

Halverson, Richard

2010-01-01

124

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

125

Monazite as an indicator of formation conditions of quartz veins at the Zhelannoe deposit, the Subpolar Urals  

NASA Astrophysics Data System (ADS)

At the Zhelannoe quartz deposit, the content of monazite attains 0.5 wt % in unaltered sericitolite and 18 wt % in hydrothermally altered sericitolite. Two monazite generations, including four varieties, characterize the sequence of formation and alteration of sericitolite bodies at the Zhelannoe deposit. Monazite of the first generation occurs in unaltered sericitolite as prismatic and tabular crystals characterized by (Nd,Ce) > La and enrichment in HREEs and ThO2 (5-16 wt %). Its formation is accompanied crystallization of milk white quartz. Monazite of the second generation occurs in altered sericitolite as the product of recrystallization of the first-generation monazite. The large drusy crystals of second-generation monazite were formed similarly with Alpine-type veins. Monazite of the second generation is characterized by Ce > (La,Nd), low contents of HREEs and ThO2 (0.5-7 wt %) and high contents of CaO and SO3 (up to 3-5 wt %). Monazite of the second generation appeared as a result of local superimposed processes and is a characteristic feature of the Zhelannoe deposit.

Repina, S. A.

2008-12-01

126

Wood formation in Angiosperms.  

PubMed

Wood formation is a complex biological process, involving five major developmental steps, including (1) cell division from a secondary meristem called the vascular cambium, (2) cell expansion (cell elongation and radial enlargement), (3) secondary cell wall deposition, (4) programmed cell death, and (5) heartwood formation. Thanks to the development of genomic studies in woody species, as well as genetic engineering, recent progress has been made in the understanding of the molecular mechanisms underlying wood formation. In this review, we will focus on two different aspects, the lignification process and the control of microfibril angle in the cell wall of wood fibres, as they are both key features of wood material properties. PMID:20371107

Déjardin, Annabelle; Laurans, Françoise; Arnaud, Dominique; Breton, Christian; Pilate, Gilles; Leplé, Jean-Charles

2010-04-01

127

Intergalactic Star Formation  

E-print Network

Star formation in interacting systems may take place in various locations, from the dust--enshrouded core of Ultraluminous Infrared Galaxies to more unusual places such as the debris of colliding galaxies expelled into the intergalactic medium. Determining whether star-formation proceeds in the latter environment, far from the parent galaxies, in a similar way as in spiral disks has motivated the multi--wavelength study presented here. We collected VLA/HI, UV/GALEX, optical Halpha and MIR/Spitzer images of a few nearby interacting systems chosen for their prominent "intergalactic" star formation activity. Preliminary results on the spectacular collisional HI ring around NGC 5291 are presented.

Duc, P A; Braine, J; Brinks, E; Lisenfeld, U; Charmandaris, V; Duc, Pierre-Alain; Boquien, Meederic; Braine, Jonathan; Brinks, Elias; Lisenfeld, Ute; Charmandaris, Vassilis

2006-01-01

128

Intergalactic Star Formation  

E-print Network

Star formation in interacting systems may take place in various locations, from the dust--enshrouded core of Ultraluminous Infrared Galaxies to more unusual places such as the debris of colliding galaxies expelled into the intergalactic medium. Determining whether star-formation proceeds in the latter environment, far from the parent galaxies, in a similar way as in spiral disks has motivated the multi--wavelength study presented here. We collected VLA/HI, UV/GALEX, optical Halpha and MIR/Spitzer images of a few nearby interacting systems chosen for their prominent "intergalactic" star formation activity. Preliminary results on the spectacular collisional HI ring around NGC 5291 are presented.

Pierre-Alain Duc; Meederic Boquien; Jonathan Braine; Elias Brinks; Ute Lisenfeld; Vassilis Charmandaris

2006-10-13

129

Format Monopolies: The Evolution of “Nationwide Format Oligopolies”  

Microsoft Academic Search

Almost ten years after the Telecommunications Act of 1996, 26 different radio station formats in Arbitron's 296 survey areas were examined in 2005 as a followup to Wirth's 2001 “Nationwide Format Oligopolies.” This longitudinal study sought to ascertain if format oligopolies (four companies reaching over 50% of a specific radio format's audience nationally) had evolved into format duopolies (two companies

Todd L. Wirth

2007-01-01

130

Poplar wood formation.  

E-print Network

??Genotypical effects on wood formation in aspen (Populus tremula x tremuloides) have been studied at morphological, ultrastructural and micro-distributional levels. To characterize transgenically in­duced modifications,… (more)

Sandquist, David

2011-01-01

131

Violent Star Formation  

NASA Astrophysics Data System (ADS)

This volume deals with the most recent theories of violent star formation. It covers the formation and evolution of new stellar clusters, and explores all the possible consequences in a wide variety of objects where massive stellar bursts have occurred. It thus presents an alternative model to that which suggests supermassive black holes are the power houses of active glactic nuclei. In addition, it analyzes the impact of Wolf-Rayet stars, stellar winds and supernovae on their host galaxy, and provides evidence of massive superassociations and of supersonic velocity dispersions that result from photo-ionization by violent star formation. This book gives a valuable overview and a timely update on all aspects of violent star formation for graduate students and researchers in the field.

Tenorio-Tagle, G.

1995-01-01

132

Understanding Earth: Coal Formation  

NSDL National Science Digital Library

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.

W.H. Freeman & Co. Publishing

133

Essays on Network Formation  

E-print Network

This dissertation contains two essays which examine the roles that individual incentives, competition, and information play in network formation. In the first essay, I examine a model in which two competing groups offer different allocation rules...

Mueller, William Graham

2012-10-19

134

MARC Format Simplification.  

ERIC Educational Resources Information Center

Summarizes the feasibility of simplifying the MARC format for bibliographic records, including the benefits, disadvantages, and consequences. Five perspectives are given: history, standards, and codes; present purposes; computer operations; library operations; and online catalogs. There are four references. (RAA)

Gapen, D. Kaye

1981-01-01

135

Display formats manual  

NASA Technical Reports Server (NTRS)

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

Runnels, R. L.

1973-01-01

136

Intergalactic Star Formation  

Microsoft Academic Search

Star formation in interacting systems may take place in various locations, from the dust--enshrouded core of Ultraluminous Infrared Galaxies to more unusual places such as the debris of colliding galaxies expelled into the intergalactic medium. Determining whether star-formation proceeds in the latter environment, far from the parent galaxies, in a similar way as in spiral disks has motivated the multi--wavelength

Pierre-Alain Duc; Meederic Boquien; Jonathan Braine; Elias Brinks; Ute Lisenfeld; Vassilis Charmandaris

2006-01-01

137

Plant Formate Dehydrogenase  

SciTech Connect

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.

John Markwell

2005-01-10

138

Autonomous Formation Flight  

NASA Technical Reports Server (NTRS)

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.

Schkolnik, Gerard S.; Cobleigh, Brent

2004-01-01

139

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

USGS Publications Warehouse

The Fredericksburg Complex, in part a migmatitic terrane in northeast Virginia, is subdivided on the basis of lithology, as well as aeromagnetic and aeroradiometric data, into two metamorphic suites. These suites are separated by the northeast-trending Spotsylvania lineament, a rectilinear geophysical feature that is probably the trace of an old fault zone. East of the lineament, the Po River Metamorphic Suite, of Proterozoic Z and (or) early Paleozoic age, consists dominantly of biotite gneiss, generally augen gneiss, and lesser amounts of hornblende gneiss and mica schist. West of the Spotsylvania lineament is the Ta River Metamorphic Suite, composed mostly of amphibolite and amphibole gneiss. However, to the southwest, along its strike belt, the Ta River contains abundant biotite gneiss and mica schist. Both the Ta River and Po River contain abundant foliated granitoid and pegmatoid bodies as concordant tabular masses and as crosscutting dikes; these rocks are considered part of the Ta River and Po River Metamorphic Suites. The amphibolitic Holly Corner Gneiss is interpreted to be a western allochthonous equivalent of the Ta River. Both the Ta River and Holly Corner are considered to be coeval, eastern, distal facies of the Lower Cambrian(?) Chopawamsic Formation. The Paleozoic Falls Run Granite Gneiss intrudes the Ta River Metamorphic Suite and the Holly Corner Gneiss; locally the Falls Run is interpreted to have been transported westward with the Holly Corner after intrusion. The Quantico Formation, in the core of the Quantico-Columbia synclinorium, rests with angular unconformity along its northwest and southeast limbs, respectively, on the Chopawamsic Formation and the Ta River Metamorphic Suite. The Quantico Formation is assigned the same Late Ordovician age and similar stratigraphic position as the Arvonia Slate of the Arvonia syncline. The youngest rocks of the area are the granitoid and pegmatoid bodies of the Falmouth Intrusive Suite. They consist of several generations of chiefly dikes and sills that are intrusive into the Fredericksburg Complex and into the Quantico Formation. Granitoid rocks also form small plutons. The Falmouth is isotopically dated as Carboniferous in age. Some of the metavolcanic rocks of the Evington Group and part of the amphibolite gneiss and amphibolite of the Hatcher Complex, named by W. B. Brown in 1969, are probably coeval with the Chopawamsic Formation and hence equivalents of the Ta River Metamorphic Suite and the Holly Corner Gneiss. The biotitic gneiss and granitoid rocks east of the Spotsylvania lineament in the Dillwyn area are considered to be coeval with the Po River Metamorphic Suite.

Pavlides, Louis

1980-01-01

140

Format-Preserving Encryption  

NASA Astrophysics Data System (ADS)

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.

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

141

Constraints on Exomoon Formation  

NASA Astrophysics Data System (ADS)

It has been widely accepted that the Earth’s moon formed by a giant impact during the late stage of the planetary formation process. The giant impact led to the formation of a debris disk around the Earth from which the Moon accreted. This type of satellite formation is considered to be common not only in the solar system (e.g., the Pluto-Charon system) but also in extrasolar systems (e.g. Ogihara & Ida 2009). However, no detailed research has been conducted on impact-induced exomoon formation. Wada et al. (2006) suggest that a vapor-rich disk is dynamically unstable and that it may not be suitable for moon formation. If this is the case, the mass and composition of a planet may affect the satellite formation process. Here, we show results from giant impact simulations of planets with various masses and compositions. We use the model suggested by Nakajima & Stevenson (2014) to estimate the vapor mass fractions of the disks. We find that the more massive and the more ice-rich the planet is, the higher the vapor mass fraction of the disk becomes. This indicates there is an upper limit of the planetary mass to form an impact-induced moon and the limit depends on the planetary composition. This upper limit is a few Earth masses for a rocky planet, and about an Earth mass for an icy planet. These results are consistent with the models that Earth’s and Pluto’s satellites formed by impacts. Although no exomoon has been detected yet, our model may be used to predict whether an observed terrestrial exoplanet could potentially have one or multiple impact-induced exomoons.

Nakajima, Miki; Genda, Hidenori; Asphaug, Erik; Ida, Shigeru

2014-11-01

142

Formation of Galactic Disks  

E-print Network

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.

S. Michael Fall

2002-03-27

143

Isolating Triggered Star Formation  

SciTech Connect

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.

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

144

Barrier cell sheath formation  

SciTech Connect

The solution for electrostatic potential within a simply modeled tandem mirror thermal barrier is seen to exhibit a sheath at each edge of the cell. The formation of the sheath requires ion collisionality and the analysis assmes that the collisional trapping rate into the barrier is considerably slower than the barrier pump rate.

Kesner, J

1980-04-01

145

Bacterial formate hydrogenlyase complex  

PubMed Central

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

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

2014-01-01

146

Bead lightning formation  

Microsoft Academic Search

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,

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

2005-01-01

147

Triglycerides and gallstone formation  

Microsoft Academic Search

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

A. H. M. Smelt

2010-01-01

148

Formation of red sprites  

Microsoft Academic Search

The properties of red sprites that are generated in the ionosphere at an altitude of 100 km are considered. A process that leads to the formation of such plasma objects is proposed. It is demonstrated that sprites are generated by acoustic waves that give rise to vortices and gas breakdown in the presence of strong gradients of gas temperature and

A. R. Aramyan; G. A. Galechyan

2009-01-01

149

Specific Star Formation Rates  

E-print Network

We present results from a study to determine how star formation contributes to galaxy growth since redshift z=1.5. Using galaxies from the MUnich Near-Infrared Cluster Survey (MUNICS) and the FORS Deep Field (FDF), we investigate the specific star formation rate (SSFR, star formation rate [SFR] per unit galaxy stellar mass) as a function of galaxy stellar mass and redshift. We test the compatibility of our results with a sample drawn from a larger volume using the Sloan Digital Sky Survey. We find that the SSFR decreases as galaxy stellar mass increases, suggesting that star formation contributes more to the growth of low-mass galaxies than high-mass galaxies at all redshifts in this study. We also find a ridge in the SSFR that runs parallel to lines of constant SFR and decreases by a factor of 10 from z=1 to today, matching the results of the evolution in SFR density seen in the ``Lilly-Madau'' diagram. The ridge evolves independently of galaxy stellar mass to a particular turnover mass at the high mass end. Galaxies above the turnover mass show a sharp decrease in SSFR compared to the average at that epoch, and the turnover mass increases with redshift.

Amanda E. Bauer; Niv Drory; Gary J. Hill

2005-09-02

150

Oil Formation and Trapping  

NSDL National Science Digital Library

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.

Marshak, Stephen; Company, W. W.

151

Technobabble: File Formats.  

ERIC Educational Resources Information Center

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)

Wilson, Bradley

1999-01-01

152

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...

153

Origin and significance of organic matter in uranium deposits of Morrison Formation, San Juan Basin, New Mexico  

SciTech Connect

Primary uranium orebodies in the Morrison Formation of the San Juan Basin, New Mexico, consist of submicroscopic coffinite in a matrix of dark-colored structureless carbonaceous matter that impregnates and partially replaces the Morrison sandstones. Recognizable carbonized plant fragments are also abundant both in and near ore. The orebodies are elongated, lenticular or tabular masses; they are oriented parallel to paleochannel systems in the host rocks. Accessory minerals in the orebodies are crudely zoned. The surrounding sediments are pervasively altered, chiefly by destruction of iron oxides and reprecipitation of pyrite. Stratigraphic, structural, and radiometric evidence indicates that the orebodies are approximately the same age as their host rocks. The carbonaceous matrix of the ore has been tentatively identified as degraded humate. Geologic evidence supports this conclusion and suggests a genetic model for the origin and geology of the orebodies. According to this model, humic acids were leached from buried plant debris by ground water, during or shorly after Morrison sedimentation. The acids migrated with the ground water and eventually consolidated into streamlined, interstitial humate masses. Uranium in the ground water was chelated by the humates and subsequently reduced. Molybdenum and other metals were precipitated at the humate boundaries by hydrogen sulfide. Organic matter and reduced sulfur species were both involved in alteration of the host rocks. Post-ore processes have modified the orebodies and host rocks.

Squyres, J.B.

1980-01-01

154

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

USGS Publications Warehouse

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

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

2007-01-01

155

Pattern formation during vasculogenesis  

PubMed Central

Vasculogenesis, the assembly of the first vascular network, is an intriguing developmental process that yields the first functional organ system of the embryo. In addition to being a fundamental part of embryonic development, vasculogenic processes also have medical importance. To explain the organizational principles behind vascular patterning, we must understand how morphogenesis of tissue level structures can be controlled through cell behavior patterns that, in turn, are determined by biochemical signal transduction processes. Mathematical analyses and computer simulations can help conceptualize how to bridge organizational levels and thus help in evaluating hypotheses regarding the formation of vascular networks. Here we discuss the ideas that have been proposed to explain the formation of the first vascular pattern: cell motility guided by extracellular matrix alignment (contact guidance), chemotaxis guided by paracrine and autocrine morphogens, and sprouting guided by cell-cell contacts. PMID:22692888

Czirok, Andras; Little, Charles D.

2012-01-01

156

Drumlin Formation Library Work  

NSDL National Science Digital Library

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

Anders, Alison M.

157

Mechanisms of Stone Formation  

Microsoft Academic Search

We have reviewed the general mechanisms involved in kidney stone formation, with reference to those composed of calcium oxalate\\u000a or phosphate, uric acid, and cystine. These processes include nucleation of individual crystals, aggregation or secondary\\u000a nucleation to produce small intrarenal multicrystalline aggregates, fixation within the kidney, and further aggregation and\\u000a secondary nucleation to produce the clinical stone. The factors regulating

Vishal N. Ratkalkar; Jack G. Kleinman

158

Formation of red sprites  

Microsoft Academic Search

The properties of red sprites that are generated in the ionosphere at an altitude of 100 km are considered. A process that\\u000a leads to the formation of such plasma objects is proposed. It is demonstrated that sprites are generated by acoustic waves\\u000a that give rise to vortices and gas breakdown in the presence of strong gradients of gas temperature and

A. R. Aramyan; G. A. Galechyan

2009-01-01

159

Formation of Transient Lamellipodia  

PubMed Central

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

Zimmermann, Juliane; Falcke, Martin

2014-01-01

160

Compact toroid formation experiments  

Microsoft Academic Search

Summary form only given, as follows. A compact toroid (CT) formation experiment is discussed. The device has coaxial electrode diameters of 0.9 m (inner) and 1.25 m (outer) and an electrode length of ~1.2 m, including an expansion drift section. The CT is formed by a 0.1-0.2-T initial radial magnetic field embedded coaxial puff gas discharge. The gas puff is

J. H. Degnan; G. P. Baca; J. D. Beason; M. E. Dearborn; D. Dietz; K. E. Hackett; J. L. Holmes; B. W. Mullins; J. L. Mullins; E. L. Ruden; D. W. Price; C. R. Sovinec; D. Gale; J. D. Graham; D. Ralph; M. Scott; W. Sommars; G. Bird; S. K. Coffey; S. W. Seiler; G. F. Kiuttu; R. E. Peterkin; N. F. Roderick; P. Turchi

1990-01-01

161

The Star Formation Camera  

Microsoft Academic Search

The Star Formation Camera (SFC) is a wide-field (~15'x19, >280 arcmin^2), high-resolution (18x18 mas pixels) UV\\/optical dichroic camera designed for the Theia 4-m space-borne space telescope concept. SFC will deliver diffraction-limited images at lambda > 300 nm in both a blue (190-517nm) and a red (517-1075nm) channel simultaneously. Our aim is to conduct a comprehensive and systematic study of the

Paul A. Scowen; Rolf Jansen; Matthew Beasley; Daniela Calzetti; Steven Desch; Alex Fullerton; John Gallagher; Doug Lisman; Steve Macenka; Sangeeta Malhotra; Mark McCaughrean; Shouleh Nikzad; Robert O'Connell; Sally Oey; Deborah Padgett; James Rhoads; Aki Roberge; Oswald Siegmund; Stuart Shaklan; Nathan Smith; Daniel Stern; Jason Tumlinson; Rogier Windhorst; Robert Woodruff

2009-01-01

162

Hail Formation in Florida  

NASA Astrophysics Data System (ADS)

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.

Stanley, Matthew

163

Cosmic Star Formation History  

E-print Network

Over the last decade and a half, an avalanche of new data from multiwavelength imaging and spectroscopic surveys has revolutionized our view of galaxy formation and evolution. Making sense of it all and fitting it together into a coherent picture remains one of astronomy's great challenges. Here we review the range of complementary techniques and theoretical tools that are allowing 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 from modern galaxy surveys, whereby the star formation rate density peaked about 3.5 Gyr after the Big Bang, at redshift 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 redshift 1.3. Less than 1% of today's stars formed during the epoch of reionization, at redshift greater than 6. Under the simple assumption of a universal initial mass func...

Madau, Piero

2014-01-01

164

Tetrahedron Formation Control  

NASA Technical Reports Server (NTRS)

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

Guzman, Jose J.

2003-01-01

165

Mars brine formation experiment  

NASA Technical Reports Server (NTRS)

Evaporites, particularly carbonates, nitrates, and sulfates, may be major sinks of volatiles scavenged from the martian atmosphere. Mars is thought to have once had a denser, warmer atmosphere that permitted the presence of liquid surface water. The conversion of atmospheric CO2 into carbonate is hypothesized to have degraded the martian climate to its present state of a generally subfreezing, desiccated desert. The rate for such a conversion under martian conditions is poorly known, so the time scale of climate degradation by this process cannot be easily evaluated. If some models are correct, carbonate formation may have been fast at geological time scales. The experiments of Booth and Kieffer also imply fast (10(exp 6) - 10(exp 7) yr) removal of the missing CO2 inventory, estimated to be 1 - 5 bar, by means of carbonate formation. The timing of formation of many of the fluvial features observed on Mars is, in large part, dependent on when and how fast the atmosphere changed. A knowledge of the rate at which carbonates and nitrates formed is also essential for assessing the probability that life, or its chemical precursors, could have developed on Mars. No previous experiments have quantitatively evaluated the rate of solution for a suite of mobile anions and cations from unaltered minerals and atmospheric gases into liquid water under Mars-like conditions. Such experiments are the focus of this task.

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

1992-01-01

166

The Star Formation Camera  

E-print Network

The Star Formation Camera (SFC) is a wide-field (~15'x19, >280 arcmin^2), high-resolution (18x18 mas pixels) UV/optical dichroic camera designed for the Theia 4-m space-borne space telescope concept. SFC will deliver diffraction-limited images at lambda > 300 nm in both a blue (190-517nm) and a red (517-1075nm) channel simultaneously. Our aim is to conduct a comprehensive and systematic study of the astrophysical processes and environments relevant for the births and life cycles of stars and their planetary systems, and to investigate and understand the range of environments, feedback mechanisms, and other factors that most affect the outcome of the star and planet formation process. This program addresses the origins and evolution of stars, galaxies, and cosmic structure and has direct relevance for the formation and survival of planetary systems like our Solar System and planets like Earth. We present the design and performance specifications resulting from the implementation study of the camera, conducted ...

Scowen, Paul A; Beasley, Matthew; Calzetti, Daniela; Desch, Steven; Fullerton, Alex; Gallagher, John; Lisman, Doug; Macenka, Steve; Malhotra, Sangeeta; McCaughrean, Mark; Nikzad, Shouleh; O'Connell, Robert; Oey, Sally; Padgett, Deborah; Rhoads, James; Roberge, Aki; Siegmund, Oswald; Shaklan, Stuart; Smith, Nathan; Stern, Daniel; Tumlinson, Jason; Windhorst, Rogier; Woodruff, Robert

2009-01-01

167

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

SciTech Connect

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.

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

1993-03-15

168

Flexible formation configuration for terrain following flight: Formation keeping constraints  

NASA Astrophysics Data System (ADS)

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

Latyshev, Simon

169

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)

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.

Hongo, Chuki

2012-03-01

170

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

SciTech Connect

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

Flores, R.M.; Johnson, S.Y. [Geological Survey, Denver, CO (United States)

1995-04-01

171

Liposome formation in microgravity  

NASA Astrophysics Data System (ADS)

Liposomes are artificial vesicles with a phospholipid bilayer membrane. The formation of liposomes is a self-assembly process that is driven by the amphipathic nature of phospholipid molecules and can be observed during the removal of detergent from phospholipids dissolved in detergent micelles. As detergent concentration in the mixed micelles decreases, the non-polar tail regions of phospholipids produce a hydrophobic effect that drives the micelles to fuse and form planar bilayers in which phospholipids orient with tail regions to the center of the bilayer and polar head regions to the external surface. Remaining detergent molecules shield exposed edges of the bilayer sheet from the aqueous environment. Further removal of detergent leads to intramembrane folding and membrane vesiculation, forming liposomes. We have observed that the formation of liposomes is altered in microgravity. Liposomes that were formed at 1-g did not exceed 150 nm in diameter, whereas liposomes that were formed during spaceflight exhibited diameters up to 2000 nm. Using detergent-stabilized planar bilayers, we determined that the stage of liposome formation most influenced by gravity is membrane vesiculation. In addition, we found that small, equipment-induced fluid disturbances increased vesiculation and negated the size-enhancing effects of microgravity. However, these small disturbances had no effect on liposome size at 1-g, likely due to the presence of gravity-induced buoyancy-driven fluid flows (e.g., convection currents). Our results indicate that fluid disturbances, induced by gravity, influence the vesiculation of membranes and limit the diameter of forming liposomes.

Claassen, D. E.; Spooner, B. S.

172

Adiabatic Halo Formation  

SciTech Connect

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.

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

173

Galaxy formation and evolution  

NASA Technical Reports Server (NTRS)

The presence of high-z quasars and radio galaxies indicates that galaxy formation began at z greater than 5, but leaves unanswered the question of when the bulk of galaxies formed. Recent near-infrared number counts of galaxies strongly favor a cosmological geometry with q0 = 0.5 and Lambda = 0. Such a model grossly underpredicts blue galaxy counts. Spectroscopy shows that the excess blue galaxies at B = 24 are dwarfs at z = 0.4, which are no longer seen at the present time. These dwarfs must contain a large amount of baryonic matter which is not included in current estimates of baryonic Omega.

Cowie, Lennox L.

1991-01-01

174

Galaxy formation and evolution  

NASA Technical Reports Server (NTRS)

The presence of high z quasars and radio galaxies tells us that galaxy formation began at z greater than 5, but leaves unanswered the question of when the bulk of galaxies formed. Recent near infrared number counts of galaxies strongly favor a cosmological geometry with q(sub 0) = 0.5 and lambda = 0. Such a model grossly underpredicts blue galaxy counts. Spectroscopy shows that the excess blue galaxies at B = 24 are dwarfs at z approximately equals 0.4 which are no longer seen at the present time. These dwarfs must contain a large amount of baryonic matter which is not included in current estimates of baryonic omega .

Cowie, Lennox L.

1991-01-01

175

Quantum Effects and Cluster Formation  

E-print Network

The causal interpretation of quantum mechanics is applied to the universe as a whole and the problem of cluster formation is studied in this framework. It is shown that the quantum effects be the source of the cluster formation.

Ali Shojai; Fatimah Shojai

2002-11-13

176

Star Formation in Irregular Galaxies.  

ERIC Educational Resources Information Center

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)

Hunter, Deidre; Wolff, Sidney

1985-01-01

177

Method for measuring pollutant formation  

NASA Technical Reports Server (NTRS)

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.

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

2001-01-01

178

Planet Formation - Overview  

NASA Technical Reports Server (NTRS)

Modern theories of star and planet formation are based upon observations of planets and smaller bodies within our own Solar System, exoplanets &round normal stars and of young stars and their environments. Terrestrial planets are believed to grow via pairwise accretion until the spacing of planetary orbits becomes large enough that the configuration is stable for the age of the system. Giant planets begin their growth as do terrestrial planets, but they become massive enough that they are able to accumulate substantial amounts of gas before the protoplanetary disk dissipates. These models predict that rocky planets should form in orbit about most single stars. It is uncertain whether or not gas giant planet formation is common, because most protoplanetary disks may dissipate before solid planetary cores can grow large enough to gravitationally trap substantial quantities of gas. A potential hazard to planetary systems is radial decay of planetary orbits resulting from interactions with material within the disk. Planets more massive than Earth have the potential to decay the fastest, and may be able to sweep up smaller planets in their path.

Lissauer, Jack J.

2005-01-01

179

Egg Formation in Lepidoptera  

PubMed Central

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

Telfer, William H.

2009-01-01

180

Deep Water Formation  

NASA Technical Reports Server (NTRS)

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.

Killworth, P. D.

1984-01-01

181

Urbanization and slum formation.  

PubMed

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

Ooi, Giok Ling; Phua, Kai Hong

2007-05-01

182

Parametrising Star Formation Histories  

E-print Network

We examine the star formation histories (SFHs) of galaxies in smoothed particle hydrodynamics (SPH) simulations, compare them to parametric models that are commonly used in fitting observed galaxy spectral energy distributions, and examine the efficacy of these parametric models as practical tools for recovering the physical parameters of galaxies. The commonly used tau-model, with SFR ~ exp(-t/tau), provides a poor match to the SFH of our SPH galaxies, with a mismatch between early and late star formation that leads to systematic errors in predicting colours and stellar mass-to-light ratios. A one-parameter lin-exp model, with SFR ~ t*exp(-t/tau), is much more successful on average, but it fails to match the late-time behavior of the bluest, most actively star-forming galaxies and the passive, "red and dead" galaxies. We introduce a 4-parameter model, which transitions from lin-exp to a linear ramp after a transition time, which describes our simulated galaxies very well. We test the ability of these paramet...

Simha, Vimal; Conroy, Charlie; Dave, Romeel; Fardal, Mark; Katz, Neal; Oppenheimer, Benjamin D

2014-01-01

183

Simulating Cosmic Structure Formation  

E-print Network

We describe cosmological simulation techniques and their application to studies of cosmic structure formation, with particular attention to recent hydrodynamic simulations of structure in the high redshift universe. Collisionless N-body simulations with Gaussian initial conditions produce a pattern of sheets, filaments, tunnels, and voids that resembles the observed large scale galaxy distribution. Simulations that incorporate gas dynamics and dissipation form dense clumps of cold gas with sizes and masses similar to the luminous parts of galaxies. Models based on inflation and cold dark matter predict a healthy population of high redshift galaxies, including systems with star formation rates of 20 M_{\\sun}/year at z=6. At z~3, most of the baryons in these models reside in the low density intergalactic medium, which produces fluctuating Lyman-alpha absorption in the spectra of background quasars. The physical description of this ``Lyman-alpha forest'' is particularly simple if the absorption spectrum is viewed as a 1-dimensional map of a continuous medium instead of a collection of lines. The combination of superb observational data and robust numerical predictions makes the Lyman-alpha forest a promising tool for testing cosmological models.

David H. Weinberg; Neal Katz; Lars Hernquist

1997-08-22

184

Urbanization and Slum Formation  

PubMed Central

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

Phua, Kai Hong

2007-01-01

185

Formation control for cooperative surveillance  

E-print Network

. The formation control scheme proposed in this work is based on a fusion of leader-follower and virtual reference approaches. This scheme gives a formation constraint representation that is independent of the number of agents in the formation and the resulting...

Woo, Sang-Bum

2009-05-15

186

Star formation and molecular clouds  

NASA Technical Reports Server (NTRS)

Several differnt stages can be discerned within the star formation process. Star formation can be considered to start when a molecular cloud fragments into many clumps. Many different physical processes are likely to play an important role in star formation, including self-gravity, magnetic fields, rotation, winds, and radiation transport. The current knowledge on some of these processes are reviewed.

Tielens, Alexander G. G. M.

1988-01-01

187

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

E-print Network

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.

Uta Fritze

2008-01-15

188

Prominence Formation and Oscillations  

E-print Network

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

Chen, P F

2014-01-01

189

Ferricyanide-humate formation  

NASA Astrophysics Data System (ADS)

We studied the complexation of ferricyanide ion by humic substances (HS) at acidic, neutral and basic pH by means of cyclic voltammetry (CV) and UV-visible spectroscopy. The CV measurements carried out at pH 3.5 and 7 showed that the first addition of HS (0.05 mg mL^{-1} of organic carbon) to ferricyanide solution caused a shift of both cathodic and anodic peak potentials together with a depression of the corresponding peak currents. After successive addition of HS further depression of peak currents were observed. Experiments perfonned at pH 12.5 showed no changes in peak current and peak potential after addition of HS. These results suggested the formation of ferricyanide-HS complexes at pH 3.5 and 7 and were confirmed by UV-Vis spectra recorded in concomitance to voltammetric measurements.

Leita, L.; Petruzzelli, G.; Fornasier, F.

2003-05-01

190

Germane vs. digermane formation.  

PubMed

Oxidative addition reactions of dialkylchalcogenanes R2E2 and [Me2Si(Nt-Bu)2]Ge 1 yielded bis(alkylchalcogeno)germanes Me2Si(Nt-Bu)2Ge(ER)2 (R = Et, E = S 2, Se 3; R = Me, E = Se 4) and digermanes [Me2Si(Nt-Bu)2Ge(EEt)]2 (E = S 5, Se 6). The reaction of 1 with Et2Te2 proceeds with formation of Me2Si(Nt-Bu)2Ge(TeEt)27, which slowly converts into the Te-bridged complex [Me2Si(Nt-Bu)2GeTe]28. 1-6 and 8 were characterized by single crystal X-ray diffraction. PMID:25354698

Steiniger, P; Bendt, G; Bläser, D; Wölper, C; Schulz, S

2014-12-18

191

Parametrically forced pattern formation.  

PubMed

Pattern formation in a nonlinear damped Mathieu-type partial differential equation defined on one space variable is analyzed. A bifurcation analysis of an averaged equation is performed and compared to full numerical simulations. Parametric resonance leads to periodically varying patterns whose spatial structure is determined by amplitude and detuning of the periodic forcing. At onset, patterns appear subcritically and attractor crowding is observed for large detuning. The evolution of patterns under the increase of the forcing amplitude is studied. It is found that spatially homogeneous and temporally periodic solutions occur for all detuning at a certain amplitude of the forcing. Although the system is dissipative, spatial solitons are found representing domain walls creating a phase jump of the solutions. Qualitative comparisons with experiments in vertically vibrating granular media are made. (c) 2001 American Institute of Physics. PMID:12779440

Armbruster, Dieter; George, Marguerite; Oprea, Iuliana

2001-03-01

192

Pattern Formation in Materials  

NASA Astrophysics Data System (ADS)

Pattern formation is ubiquitous in nature, from sand ripples formed by wind to the development of a complex biological organism with different organs and a central nervous system. In the realm of materials, patterns are formed invariably when matter is transformed between different solid, liquid or gaseous states far from thermodynamic equilibrium. Material failure is itself mediated by the propagation of cracks that form intricate patterns. Understanding how patterns form and evolve is key to design materials with desired properties and to optimize their performance and safety. This talk will discuss recent progress made to understand three distinct class of patterns including the highly branched snow-flake-like dendritic patterns formed during the solidification process, polycrystalline patterns shaped by grain boundaries, and crack patterns.

Karma, Alain

2011-04-01

193

Group Formation in Economics  

NASA Astrophysics Data System (ADS)

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

Demange, Gabrielle; Wooders, Myrna

2005-01-01

194

Chorionic Villi Formation  

NSDL National Science Digital Library

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.

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

2010-11-29

195

Dityrosine formation in calmodulin  

SciTech Connect

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.

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

1987-02-10

196

Galaxy formation by dust  

NASA Technical Reports Server (NTRS)

It has been known since the early 1940's that radiation can cause an instability in the interstellar medium. Absorbing dust particles in an isotropic radiation field shadow each other by a solid angle which is inversely proportional to the square of the distance between the two particles, leading to an inverse-square attractive force - mock gravity. The effect is largest in an optically thin medium. Recently Hogan and White (HW, hereafter) proposed that if the pre-galactic universe contained suitable sources of radiation and dust, instability in the dust distribution caused by mock gravity may have led to the formation of galaxies and galaxy clusters. In their picture of a well-coupled dust-gas medium, HW show that mock gravity begins to dominate gravitational instability when the perturbation becomes optically thin, provided that the radiation field at the time is strong enough. The recent rocket observation of the microwave background at submillimeter wavelengths by Matsumoto et al. might be from pre-galactic stars, the consequence of the absorption of ultraviolet radiation by dust, and infrared reemission which is subsequently redshifted. HW's analysis omits radiative drag, incomplete collisional coupling of gas and dust, finite dust albedo, and finite matter pressure. These effects could be important. In a preliminary calculation including them, the authors have confirmed that mock gravitational instability is effective if there is a strong ultraviolet radiation at the time, but any galaxies that form would be substantially enriched in heavy elements because the contraction of the dust is more rapid than that of the gas. Moreover, since the dust moves with supersonic velocity through the gas soon after the perturbation becomes optically thin, the sputtering of dust particles by gas is significant, so the dust could disappear before the instability develops significantly. They conclude that the mock gravity by dust is not important in galaxy formations.

Wang, Boqi; Field, Goerge B.

1989-01-01

197

Medusae Fossae Formation  

NASA Technical Reports Server (NTRS)

(Released 16 April 2002) The Science This THEMIS visible image was acquired near 11o N, 159o W (201o E) and shows examples of the remarkable variations that can be seen in the erosion of the Medusae Fossae Formation. This Formation is a soft, easily eroded deposit that extends for nearly 1,000 km along the equator of Mars. In this region, like many others throughout the Medusae Fossae Formation, the surface has been eroded by the wind into a series of linear ridges called yardangs. These ridges generally point in direction of the prevailing winds that carved them, and demonstrate the power of martian winds to erode the landscape of Mars. The easily eroded nature of the Medusae Fossae Formation suggests that it is composed of weakly cemented particles, and was most likely formed by the deposition of wind-blown dust or volcanic ash. Within this single image it is possible to see differing amounts of erosion and stripping of layers in the Medusae Fossae Formation. Near the bottom (southern) edge of the image a rock layer with a relatively smooth upper surface covers much of the image. Moving upwards (north) in the image this layer becomes more and more eroded. At first there are isolated regions where the smooth unit has been eroded to produce sets of parallel ridges and knobs. Further north these linear knobs increase in number, and only small, isolated patches of the smooth upper surface remain. Finally, at the top of the image, even the ridges have been removed, exposing the remarkably smooth top of hard, resistant layer below. This sequence of layers with differing hardness and resistance to erosion is common on Earth and on Mars, and suggests significant variations in the physical properties, composition, particle size, and/or cementation of these martian layers. As is common throughout the Medusae Fossae Formation, very few impact craters are visible, indicating that the surface exposed is relatively young, and that the process of erosion may be active today. The Story 'Yardang!' Now, that may seem like a peculiar-sounding curse word, but nobody would get in trouble for using it. A yardang is one of the very cool-sounding words geologists use to describe long, irregular features like the ones seen in this image. Yardangs are grooved, furrowed ridges that form as the wind erodes away weakly cemented material in the region. Rippling across the surface, yardangs tell the story of how the powerful Martian wind carved the surface into such a gorgeous pattern over time. (Don't miss clicking on the above image to see a detailed view, in which the beauty and almost dance-like symmetry of the waving terrain pops out in highly compelling, three-dimensional texture.) It may be easy to see which way the wind blows in this area, since these streamlined features point in the direction of prevailing winds. But how can geologists understand the various kinds of terrain seen here? First, they have to study the different patterns of erosion, looking closely at how the wind has stripped off certain layers and not others. Want to be a geologist yourself? Start at the bottom of the image and scroll upward, and see how the relatively smooth, higher terrain toward the south gradually becomes more and more eroded. Moving up the image, at first you?ll see only a few, isolated regions of parallel ridges and knolls. Go a little farther north with your eyes (toward the center of the image), and you?ll see how these linear knobs really get going! Once you get to the top of the image, only patches of these grooved ridges remain, leaving an incredibly smooth, wind-scrubbed surface behind. You know this layer has to be made of pretty hard material, because it seems impervious to further erosion. Geologists studying Mars can compare these Martian yardangs to examples found on Earth, such as those in the Lut desert of Iran. Humans have even been known to use the wind as their inspiration, sculpting the shape of yardangs themselves. The famous sphynx at Giza in Egypt is thought to be a yardang that's been whittled

2002-01-01

198

BUGSDAT: Stata module to convert a Stata datafile into the S-plus format used in Winbugs  

Microsoft Academic Search

bugsdat will convert selected variables from the loaded Stata dataset into a text file that can be read into the WinBUGS software package. The text file is created using a log file so will automatically close open log files. The resulting file will be an ASCII file that can be easily cut and pasted into WinBUGS.

Adrian Mander

2006-01-01

199

Bead lightning formation  

SciTech Connect

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.

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

200

Bead lightning formation  

NASA Astrophysics Data System (ADS)

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.

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

2005-09-01

201

Formation of "bound  

NASA Astrophysics Data System (ADS)

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

Nowak, K.; Kästner, M.; Miltner, A.

2009-04-01

202

Prominence formation and oscillations  

NASA Astrophysics Data System (ADS)

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

Chen, P. F.

203

Nuclear ``pasta'' formation  

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

204

Gaining Insight into Star Formation: Resolved Star Formation Laws  

NASA Astrophysics Data System (ADS)

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

Liebst, Kelley; Scowen, Paul A.

2014-06-01

205

Educational Products Videotapes (VHS format, other formats by  

E-print Network

Educational Products DVDs Videotapes (VHS format, other formats by special request) and DVDs (-R://sprott.physics.wisc.edu/wop.htm#videos The quality of the DVDs is much higher than what you see from the streamed version. Lecture Kit A kit = Adult M) For more information or to place an order for T-shirts, DVDs or Lecture Kits contact: (608) 262

Saffman, Mark

206

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

ERIC Educational Resources Information Center

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…

Keeley, Page

2013-01-01

207

Medusae Fossae Formation  

NASA Technical Reports Server (NTRS)

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

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

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

1998-01-01

208

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)

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.

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

2014-09-01

209

Star formation in the multiverse  

NASA Astrophysics Data System (ADS)

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

Bousso, Raphael; Leichenauer, Stefan

2009-03-01

210

Science Sampler: Formative assessment guideposts  

NSDL National Science Digital Library

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.

Ayala, Carlos

2005-01-01

211

The Epoch of Galaxy Formation  

Microsoft Academic Search

We use a semianalytic model of galaxy formation in hierarchical clustering theories to interpret recent data on galaxy formation and evolution, focusing primarily on the recently discovered population of Lyman-break galaxies at z ~= 3. For a variety of cold dark matter (CDM) cosmologies, we construct mock galaxy catalogs subject to selection criteria identical to those applied to the real

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

1998-01-01

212

Motivating Students through Formative Feedback  

ERIC Educational Resources Information Center

Technology tools that are used to help apply standards and benchmarks motivate physical educators to use new methods of teaching, and create new ways to provide students with direct formative feedback, the number one motivator for students. Direct formative feedback refers to verbal communication between the teacher and/or parent and student. The…

Mauch, Lois

2007-01-01

213

FORMATION OF SECONDARY ORGANIC AEROSOL  

EPA Science Inventory

(1) Gas-phase chemistry. With the clear and profound effect of the VOC/NOx ratio on SOA formation, we will augment gas-phase VOC oxidation mechanisms in atmospheric models to account for the effect of NOx level on the mechanism of SOA formation; (2) Revis...

214

Formation of the solar system  

Microsoft Academic Search

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

C. Hayashi; K. Nakazawa; Y. Nakagawa

1985-01-01

215

Mechanism of tornado funnel formation  

Microsoft Academic Search

The mechanism of formation of a tornado funnel was observed in a specially designed facility for tornado simulation. In this facility, a tornado cyclone is first simulated at the exit of a vortex generator. Interaction of this vortex with a ground plane is found to be responsible for the funnel formation. Time-averaged velocity measurements indicate that a smaller, but highly

C. T. Hsu; B. Fattahi

1976-01-01

216

New Frontiers in Formative Assessment  

ERIC Educational Resources Information Center

"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…

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

2011-01-01

217

Formative Assessment: A Critical Review  

ERIC Educational Resources Information Center

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

Bennett, Randy Elliot

2011-01-01

218

VEHICLE NETWORKS: ACHIEVING REGULAR FORMATION  

Microsoft Academic Search

In this paper we will consider a network of vehicles exchanging information among themselves with the intention of achieving a specied polygonal formation. The network achieves the formation through decentralized feedback control, which is con- structed from the available information. Several information o w laws are considered in order to improve the performance of the vehicle network. A stochastic model

MADALENA CHAVES; ROBERT DAY; LUCIA GOMEZ-RAMOS; PARTHASARATHI NAG; ANCA WILLIAMS; WEI ZHANG

2002-01-01

219

The Apennine Bench Formation revisited  

NASA Technical Reports Server (NTRS)

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.

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

1985-01-01

220

Accretion processes in star formation  

Microsoft Academic Search

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

Lee Hartmann

1998-01-01

221

Formative Automated Computer Testing (FACT).  

ERIC Educational Resources Information Center

Describes the development of a tool, FACT (Formative Automated Computer Testing), to formatively assess information technology skills of college students in the United Kingdom. Topics include word processing competency; tests designed by tutors and delivered via a network; and results of an evaluation that showed students preferred automated…

Hunt, Nicoll; Hughes, Janet; Rowe, Glenn

2002-01-01

222

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 ...

223

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...

224

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

USGS Publications Warehouse

The Miocene Bear Lake Formation is exposed along the coast and mountains of the central Alaska Peninsula and extends offshore as part of the Bristol Bay Basin. The Bear Lake Formation is up to 2360 m (7743 ft) thick in an offshore well and is considered to have the highest reservoir potential in this gasrich frontier basin. Our new macrofossil and palynological data, collected in the context of measured stratigraphic sections, allow us to construct the first chronostratigraphic framework for this formation. Biostratigraphic age assignments for the numerous, commonly isolated, onshore exposures of the Bear Lake Formation show that deposition initiated sometime before the middle Miocene (15 Ma) and extended to possibly the earliest Pliocene. The bulk of the Bear Lake Formation, however, was deposited during the middle and late Miocene based on our new findings. We interpret the Bear Lake Formation as the product of a regional transgressive estuarine depositional system based on lithofacies analysis. The lower part of the formation is characterized by trough cross-stratified sandstone interbedded with coal and pedogenic mudstone deposited in fluvial and swamp environments of the uppermost parts of the estuarine system. The lower-middle part of the formation is dominated by nonbioturbated, wavy- and flaser-bedded sandstone and siltstone that were deposited in supratidal flat environments. The uppermiddle part of the Bear Lake Formation is characterized by inclined heterolithic strata and coquinoid mussel beds that represent tidal channel environments in the middle and lower tracts of the estuarine system. The uppermost part of the formation consists of tabular, bioturbated sandstone with diverse marine invertebrate macrofossil faunas. We interpret this part of the section as representing the subtidal tract of the lower estuarine system and possibly the adjacent shallow inner shelf. A comparison of our depositional framework for the Bear Lake Formation with core and well-log data from onshore and offshore wells indicates that similar Miocene depositional systems existed throughout much of the Bristol Bay Basin. The documented changes in depositional environments within the Bear Lake Formation are also important for understanding upsection changes in the geometries of potential reservoirs. Copyright ??2009. The American Association of Petroleum Geologists. All rights reserved.

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

2009-01-01

225

Formation of interstellar anions  

NASA Astrophysics Data System (ADS)

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

Senent, Maria Luisa

2012-05-01

226

Galaxy formation and chemical evolution  

E-print Network

The manner the galaxy accretes matter along with the star formation rates at different epochs, influence the evolution of the stable isotopic inventories of the galaxy. A detailed analysis is presented here to study the dependence of the galactic chemical evolution on the accretion scenario of the galaxy along with the star formation rate during the early accretionary phase of the galactic thick disk and thin disk. Our results indicate that a rapid early accretion of the galaxy during the formation of the galactic thick disk along with an enhanced star formation rate in the early stages of the galaxy accretion could explain the majority of the galactic chemical evolution trends of the major elements. Further, we corroborate the recent suggestions regarding the formation of a massive galactic thick disk rather than the earlier assumed low mass thick disk.

Sahijpal, S

2014-01-01

227

Tubulogenesis during blood vessel formation  

PubMed Central

The ability to form and maintain a functional system of contiguous hollow tubes is a critical feature of vascular endothelial cells (ECs). Lumen formation, or tubulogenesis, occurs in blood vessels during both vasculogenesis and angiogenesis in the embryo. Formation of vascular lumens takes place prior to the establishment of blood flow and to vascular remodeling which results in a characteristic hierarchical vessel organization. While epithelial lumen formation has received intense attention in past decades, more recent work has only just begun to elucidate the mechanisms controlling the initiation and morphogenesis of endothelial lumens. Studies using in vitro and in vivo models, including zebrafish and mammals, are beginning to paint an emerging picture of how blood vessels establish their characteristic morphology and become patent. In this chapter, we review and discuss the molecular and cellular mechanisms driving the formation of vascular tubes, primarily in vivo, and we compare and contrast proposed models for blood vessel lumen formation. PMID:21624487

Xu, Ke; Cleaver, Ondine

2011-01-01

228

Double layer formation. [in plasma  

NASA Technical Reports Server (NTRS)

An investigation is conducted of the plasma processes which occur during the formation of a double layer in response to an applied initial electric field, when triggered by a current in the plasma. The important feature of the formation process was the creation of an ion-rich plasma-density cavity. The positive space charge of the cavity was shielded by induction of a negative space charge on the low potential side of the cavity, giving rise to the formation of a fully developed double layer. The shielding was complete only when the electron current from the low potential side exceeded the electron thermal current. It was found that during the formation of double layers counterstreaming electrons are generated. Moreover, transient double layers with reverse polarity also occur during this phase. Thus, the recurring formation of double layers can give rise to flickering double layers.

Singh, N.

1982-01-01

229

BOREAS Derived Surface Meteorological Data  

NASA Technical Reports Server (NTRS)

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.

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

2000-01-01

230

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

NASA Technical Reports Server (NTRS)

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.

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

2000-01-01

231

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

NASA Technical Reports Server (NTRS)

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.

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

2000-01-01

232

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

NASA Technical Reports Server (NTRS)

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.

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

2000-01-01

233

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

NASA Technical Reports Server (NTRS)

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.

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

2000-01-01

234

BOREAS TF-11 SSA-Fen Leaf Gas Exchange Data  

NASA Technical Reports Server (NTRS)

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.

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

2000-01-01

235

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

NASA Technical Reports Server (NTRS)

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.

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

2000-01-01

236

BOREAS TE-22 Allometric Forest Survey Data  

NASA Technical Reports Server (NTRS)

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).

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

2000-01-01

237

The Formation of Massive Stars  

E-print Network

Massive stars have a profound influence on the Universe, but their formation remains poorly understood. We review the current status of observational and theoretical research in this field, describing the various stages of an evolutionary sequence that begins with cold, massive gas cores and ends with the dispersal and ionization of gas by the newly-formed star. The physical processes in massive star formation are described and related to their observational manifestations. Feedback processes and the relation of massive stars to star cluster formation are also discussed. We identify key observational and theoretical questions that future studies should address.

H. Beuther; E. B. Churchwell; C. F. McKee; J. C. Tan

2006-02-01

238

Dissipative processes in galaxy formation.  

PubMed Central

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

Silk, J

1993-01-01

239

Holographic grating formation in photopolymers  

NASA Astrophysics Data System (ADS)

We introduce a model describing real-time grating formation in holographic photopolymers, assuming that the diffusion of free monomers is much faster than the grating formation. This model, which combines polymerization kinetics with results from coupled-wave theory, indicates that the grating formation time depends sublinearly on the average holographic recording intensity and the beam intensity ratio controls the grating index modulation at saturation. We validate the model by comparing its predictions with the results of experiments in which DuPont HRF-150X001 photopolymer was used.

Piazzolla, Sabino; Jenkins, B. Keith

1996-07-01

240

Antihydrogen Formation using Cold Plasmas  

SciTech Connect

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

Madsen, N.; Bowe, P.D.; Hangst, J.S. [Department of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C (Denmark); Amoretti, M.; Carraro, C.; Macri, M.; Testera, G.; Variola, A. [Istituto Nazionale di Fisica Nucleare, Sezione di Genova, I-16146 Genova (Italy); Amsler, C.; Johnson, I.; Pruys, H.; Regenfus, C. [Physik-Institut, Zuerich University, CH-8057 Zurich (Switzerland); Bonomi, G.; Bouchta, A.; Doser, M.; Kellerbauer, A.; Landua, R. [PH Department, CERN, Geneva (Switzerland); Cesar, C.L. [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21945-970 (Brazil); Charlton, M.; Joergensen, L.V. [Department of Physics, University of Wales Swansea, Swansea SA2 8PP (United Kingdom)] [and others

2004-10-20

241

Circumstellar disks and planetary formation  

NASA Astrophysics Data System (ADS)

Circumstellar disks are the the cradle of planetary systems. They are found around a large number of intermediate- and low-mass stellar objects in star forming regions and young clusters. Their study can provide important clues about the timescales and physical conditions for planet formation. In this paper, I review some properties of circumstellar disks that come from the analysis of multi-wavelength observational data, and that are important in the context of planet formation. In addition, I also present the first evidences of planetary formation within the so-called transitional disks.

Huélamo, N.

2013-05-01

242

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

USGS Publications Warehouse

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

Steele-Mallory, B. A.

1982-01-01

243

Use-driven concept formation  

E-print Network

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 ...

Roberts, Jennifer M. (Jennifer Marie)

2010-01-01

244

Gas Behavior in Galaxy Formation  

NASA Astrophysics Data System (ADS)

This dissertation focuses on the topic of gas in galaxy formation from three different perspectives: spherical collapse, external radiative heating, and 3D collapse. The physics of galaxy formation is explored via a combination of 1D and 3D calculations. The 1D calculations, have been used to explore both simple analytic models as well as a large number of micro-physical processes (e.g., multi-species chemistry, full multi-spectrum radiative transfer, and the subsequent heating and cooling). The 3D calculations have looked at the effects of external torques and of a hierarchical gas structure, but in an environment with less micro-physics. Through this approach a variety of conclusions have drawn about the formation of bulges and disks; the absorption line signatures of mini-halos and multi-phase gas; and the role of hydrodynamics in simulating galaxy formation.

Kepner, Jeremy Victor

245

Constraining Corona Formation on Venus  

NASA Astrophysics Data System (ADS)

We model the formation of off-rift coronae at Parga Chasma in order to understand how Venus loses its heat. We find the data required to make proper comparisons between models and observations is lacking.

Piskorz, D.; Elkins-Tanton, L. T.; Smrekar, S. E.

2014-05-01

246

The multifaceted planetesimal formation process  

E-print Network

Accumulation of dust and ice particles into planetesimals is an important step in the planet formation process. Planetesimals are the seeds of both terrestrial planets and the solid cores of gas and ice giants forming by core accretion. Left-over planetesimals in the form of asteroids, trans-Neptunian objects and comets provide a unique record of the physical conditions in the solar nebula. Debris from planetesimal collisions around other stars signposts that the planetesimal formation process, and hence planet formation, is ubiquitous in the Galaxy. The planetesimal formation stage extends from micrometer-sized dust and ice to bodies which can undergo run-away accretion. The latter ranges in size from 1 km to 1000 km, dependent on the planetesimal eccentricity excited by turbulent gas density fluctuations. Particles face many barriers during this growth, arising mainly from inefficient sticking, fragmentation and radial drift. Two promising growth pathways are mass transfer, where small aggregates transfer u...

Johansen, Anders; Tanaka, Hidekazu; Ormel, Chris; Bizzarro, Martin; Rickman, Hans

2014-01-01

247

Fuel spill reports-Format  

NSF Publications Database

... EAM NSF Org: OD / OPP Date : February 05, 1991 File : opp93022 DIVISION OF POLAR PROGRAMS OFFICE OF ... Reports/Format for Fuel Spill Reports) To: Files (S.7 - Environment) Accidents involving spillage of ...

248

Cosmic strings and galaxy formation  

NASA Technical Reports Server (NTRS)

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.

Bertschinger, Edmund

1989-01-01

249

The Epoch of Galaxy Formation  

Microsoft Academic Search

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.

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

1997-01-01

250

The Formation of Stellar Clusters  

E-print Network

We review recent work that investigates the formation of stellar clusters, ranging in scale from globular clusters through open clusters to the small scale aggregates of stars observed in T associations. In all cases, recent advances in understanding have been achieved through the use of state of the art stellar dynamical and gas dynamical calculations, combined with the possibility of intercomparison with an increasingly large dataset on young clusters. Among the subjects that are highlighted are the frequency of cluster-mode star formation, the possible relationship between cluster density and the highest stellar mass, subclustering and the dynamical interactions that occur in compact aggregates, such as binary star formation. We also consider how the spectrum of stellar masses may be shaped by the process of competitive accretion in dense environments and how cluster properties, such as mass segregation and cluster morphology, can be used in conjunction with numerical simulations to investigate the initial conditions for cluster formation. Lastly, we contrast bottom-up and top-down scenarios for cluster formation and discuss their applicability to the formation of clusters on a range of scales.

Cathie J. Clarke; Ian A. Bonnell; Lynne A. Hillenbrand

1999-03-22

251

Treating tar sands formations with karsted zones  

SciTech Connect

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.

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

2010-03-09

252

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

E-print Network

a particular combination, that is, a person of some gender sitting in some position, drinking some soda-numbered seats are Kate, Claude, and a person who didn't drink lemon soda, in some order. 1 Copyright 1999, Dell, representing name, gender, position, soda and country (each with its associated domain). Each row represents

Truszczynski, Miroslaw

253

Exact, Heuristic and Metaheuristic Methods for Confidentiality Protection by Controlled Tabular Adjustment  

Microsoft Academic Search

Government agencies and commercial organizations that report data face the task of representing the data meaningfully while simultaneously protecting the confidentiality of critical data components. The challenge is to organize and disseminate data in a form that prevents these components from being unmasked by corporate espionage, or falling prey to efforts to penetrate the security of the information underlying the

Fred Glover; Lawrence H. Cox; James P. Kelly; Rahul Patil

2008-01-01

254

Interactive analysis and display of tabular data. [Descripton of CHART program for report design  

Microsoft Academic Search

A program for simple data analysis and report design is described. The design emphasizes flexibility, ease of use, and rapid interactive response. These considerations are discussed in relation to the choices that may be made in the analysis and display design process. The analysis may be directed and monitored at several points, data selection and calibration, binning, choice of data

W. H. Benson; B. Kitous

1977-01-01

255

Kinematic and seismic analysis of giant tabular iceberg breakup at Cape Adare, Antarctica  

NASA Astrophysics Data System (ADS)

Satellite imagery reveals that a series of large icebergs (B15B in April 2001, C19 in June 2003, and B15A in October 2005) broke up or fractured while exiting the Ross Sea in a narrowly defined area off Cape Adare, Antarctica. Examination of recent swath-mapped bathymetric observations revealed that the principle agent of these breakups is a previously unknown 9 km long ridge with minimum depths of 215 m that we call Davey Shoal. Satellite imagery shows that the icebergs are driven into the shoal by coastal currents that converge over the narrow continental shelf. One of the icebergs, the 120 km by 30 km B15A, was instrumented with a seismograph, GPS, and fluxgate compass. This instrumentation provided a unique opportunity to establish the details of the iceberg kinematics that were not revealed by satellite imagery alone and to correlate seismic events observed both on the iceberg and in the far field during breakup. B15A fractured from multiple strikes against Davey Shoal and the adjacent Possession Islands; these strikes were driven by the combination of tidal currents and the coastal mean flow. The periods of iceberg-sourced seismic radiation were correlated with the strikes. The iceberg- and land-based seismic signals showed that the iceberg fracture, its sliding across the shoals, and the ice-on-ice stick-slip contacts among the postbreakup iceberg fragments generated the strong chaotic and harmonic tremor episodes that were observed at distances as far as the South Pole, where these signals propagated as seismically coupled hydroacoustic T phases.

Martin, Seelye; Drucker, Robert; Aster, Richard; Davey, Fred; Okal, Emile; Scambos, Ted; Macayeal, Douglas

2010-06-01

256

Tabular iceberg collisions within the coastal regime Douglas R. MACAYEAL,1  

E-print Network

, University of Chicago, 5734 South Ellis Avenue, Chicago, Illinois 60637, USA E-mail: drm7@midway of Ross Island, the fixed Ross Ice Shelf and grounded C16. Iceberg interactions in the near-coastal regime part by the presence of the icebergs in the vicinity of the US research base on Ross Island, Antarctica

Boyce, C. Kevin

257

Developmental Algebra Students' Use of Prose and Tabular Representations of Functions To Construct Symbolic Models.  

ERIC Educational Resources Information Center

Reports that most of 13 developmental algebra students interviewed preferred constructing tables of values, or the combination of prose with tables, as symbolic models for additive and unit-rate functional relationships. States that these students achieved greater success rates than those who used only prose in their symbolic modeling attempts.…

Gray, Susan

2000-01-01

258

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

...information. 232.305 Section 232.305 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION REGULATION S-T-GENERAL RULES AND REGULATIONS FOR ELECTRONIC FILINGS Preparation of Electronic Submissions § 232.305 Number of...

2014-04-01

259

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

PubMed

Two facets of climate change--increased tropical storm intensity and ocean acidification--are expected to detrimentally affect reef-building organisms by increasing their mortality rates and decreasing their calcification rates. Our current understanding of these effects is largely based on individual organisms' short-term responses to experimental manipulations. However, predicting the ecologically-relevant effects of climate change requires understanding the long-term demographic implications of these organism-level responses. In this study, we investigate how storm intensity and calcification rate interact to affect population dynamics of the table coral Acropora hyacinthus, a dominant and geographically widespread ecosystem engineer on wave-exposed Indo-Pacific reefs. We develop a mechanistic framework based on the responses of individual-level demographic rates to changes in the physical and chemical environment, using a size-structured population model that enables us to rigorously incorporate uncertainty. We find that table coral populations are vulnerable to future collapse, placing in jeopardy many other reef organisms that are dependent upon them for shelter and food. Resistance to collapse is largely insensitive to predicted changes in storm intensity, but is highly dependent on the extent to which calcification influences both the mechanical properties of reef substrate and the colony-level trade-off between growth rate and skeletal strength. This study provides the first rigorous quantitative accounting of the demographic implications of the effects of ocean acidification and changes in storm intensity, and provides a template for further studies of climate-induced shifts in ecosystems, including coral reefs. PMID:23056379

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

2012-01-01

260

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

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.

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

2011-01-01

261

STAR FORMATION IN ATOMIC GAS  

SciTech Connect

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.

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

262

Formation of different types of compaction bands: Theoretical analysis and numerical models  

NASA Astrophysics Data System (ADS)

The onset and evolution of tabular compaction bands is studied based on the discontinuous bifurcation analysis and finite-difference simulations. In numerical models, the bands are initiated as constitutive instabilities resulting from the deformation bifurcation. Band spacing, length and aspect strongly depend on the constitutive parameters and particularly on the hardening modulus h, both spacing and length rapidly increasing with h. Compaction banding is only possible when h lies within certain limits h_min and h_max defined by other parameters. If h > h_max, the deformation localisation is either impossible at all or occurs in the form of shear banding, depending on the parameters. The transition from shear to compaction banding is gradual and corresponds to the formation of crooked or zigzag bands similar to those obtained in the experimental rock tests. These bands are very dense and have small wavelength when h approaches h_min. On the other hand, when h approaches h_max and at h > h_max the deformation localisation is impossible, the forming compaction bands are linear and long. After the initiation of these bands (from deformation bifurcation) some of them are dying, while others continue a post-bifurcation evolution accumulating the inelastic deformation/damage and compressive stress at their tips. This stress, however, does not exceed 0.1% of the background value. Starting from some stage, the bands begin to propagate similarly to cracks. The propagation then slows down simultaneously with the beginning of bands’ thickening that occurs due to the incorporation of not yet compacted material at the band flanks. Then the propagation practically stops and the bands undergo only the heterogeneous thickening, maximal in the middle of the band and reducing toward its tips. This scenario obtained directly in the numerical models (without any specific hypotheses about the propagation mechanism) appears more complicated than what can be expected from the LEFM anti-crack model. The band propagation distance is proportional to the initial (resulted from the bifurcation) band length that in turn is proportional to the hardening modulus and theoretically can reach infinity. The aspect of "numerical" bands is very similar to that of natural (geological as opposed to experimental) bands. They are thicker in the central band segment and are progressively thinning toward the ends. The microphysics of the observed difference between geological and experimental banding is discussed and related to the evolution (continuous versus discontinuous) of the hardening modulus with inelastic deformation.

Chemenda, A. I.

2010-12-01

263

Theories of Giant Planet Formation  

NASA Technical Reports Server (NTRS)

An overview of current theories of planetary formation, with emphasis on giant planets, is presented. The most detailed models are based upon observations of our own Solar System and of young stars and their environments. While these models predict that rocky planets should form around most single stars, the frequency of formation of gas giant planets is more difficult to predict theoretically. Terrestrial planets are believed to grow via pairwise accretion until the spacing of planetary orbits becomes large enough that the configuration is stable for the age of the system. Giant planets begin their growth as do terrestrial planets, but they become massive enough that they are able to accumulate substantial amounts of gas before the protoplanetary disk dissipates. Most models for extrasolar giant planets suggest that they formed as did Jupiter and Saturn (in nearly circular orbits, far enough from the star that ice could), and subsequently migrated to their current positions, although some models suggest in situ formation.

Lissauer, Jack J.; Young, Richard E. (Technical Monitor)

1998-01-01

264

Terrestrial versus giant planet formation  

NASA Technical Reports Server (NTRS)

Given a solar nebular surrounding the early protosun, containing dust grains that have already undergone growth through collisions to about centimeter-size, the question of the formation of the terrestrial and giant planets is considered. In contrast to the usual approach of emphasizing how well a problem is understood, the uncertainties and areas where more work needs to be done will be accentuated. Also, the emphasis will be on the dynamics of planetary formation, because profound problems still exist in this area, and because it seems most logical to concentrate first on the dynamical questions involved with assembling the planets before putting too much effort into the detailed chemical and geological consequences of certain formation mechanisms.

Boss, Alan P.

1988-01-01

265

Morphological study of penumbral formation  

NASA Astrophysics Data System (ADS)

Penumbrae are known to be areas of mainly horizontal magnetic field surrounding umbrae of relatively large and mature sunspots. In this paper, we observationally studied the formation of penumbrae in NOAA 10978, where several penumbral formations were observed in G-band images of the Solar Optical Telescope on board Hinode. Thanks to the continuous observation by Hinode, we could morphologically follow the evolution of sunspots and found that there are several paths to the penumbral formation: (1) active accumulation of magnetic flux, (2) rapid emergence of magnetic field, and (3) appearance of twisted or rotating magnetic tubes. In all of these cases, magnetic fields are expected to sustain high inclination at the edges of flux tube concentration longer than the characteristic growth time of downward magnetic pumping.

Kitai, Reizaburo; Watanabe, Hiroko; Otsuji, Ken'ichi

2014-10-01

266

Computational Modeling of Microabscess Formation  

PubMed Central

Bacterial infections can be of two types: acute or chronic. The chronic bacterial infections are characterized by being a large bacterial infection and/or an infection where the bacteria grows rapidly. In these cases, the immune response is not capable of completely eliminating the infection which may lead to the formation of a pattern known as microabscess (or abscess). The microabscess is characterized by an area comprising fluids, bacteria, immune cells (mainly neutrophils), and many types of dead cells. This distinct pattern of formation can only be numerically reproduced and studied by models that capture the spatiotemporal dynamics of the human immune system (HIS). In this context, our work aims to develop and implement an initial computational model to study the process of microabscess formation during a bacterial infection. PMID:23197993

Pigozzo, Alexandre Bittencourt; Macedo, Gilson Costa; Weber dos Santos, Rodrigo; Lobosco, Marcelo

2012-01-01

267

Structure formation in active networks  

E-print Network

Structure formation and constant reorganization of the actin cytoskeleton are key requirements for the function of living cells. Here we show that a minimal reconstituted system consisting of actin filaments, crosslinking molecules and molecular-motor filaments exhibits a generic mechanism of structure formation, characterized by a broad distribution of cluster sizes. We demonstrate that the growth of the structures depends on the intricate balance between crosslinker-induced stabilization and simultaneous destabilization by molecular motors, a mechanism analogous to nucleation and growth in passive systems. We also show that the intricate interplay between force generation, coarsening and connectivity is responsible for the highly dynamic process of structure formation in this heterogeneous active gel, and that these competing mechanisms result in anomalous transport, reminiscent of intracellular dynamics.

Simone Köhler; Volker Schaller; Andreas R. Bausch

2011-03-18

268

Biofilm formation by Clostridium difficile  

PubMed Central

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

Dapa, Tanja; Unnikrishnan, Meera

2013-01-01

269

Numerical simulations of galaxy formation  

E-print Network

The current status of numerical simulations of galaxy formation is reviewed. After a short description of the main numerical simulation techniques, three sample applications illustrate how numerical simulations have provided deeper insight in the galaxy formation process and how they have illuminated success and failure of the hierarchical galaxy formation paradigm: N-body simulations demonstrate that the density profiles of dark matter halos that form in hierarchical clustering scenarios follow a characteristic law. A comparison with the kinematics of disk galaxies however unravels that these density profiles are too concentrated. Hydrodynamical simulation show that the highly irregular velocity field of merging subclumps at redshift $z\\approx 3$ can easily account for the observed asymmetry in the absorption profiles of low ionization species in damped \\Lya absorption systems. The built-up of galaxies due to mergers is however also cause for one of the major inconsistencies of hierarchical structure formati...

Steinmetz, M

1999-01-01

270

Toward Understanding Massive Star Formation  

E-print Network

Although fundamental for astrophysics, the processes that produce massive stars are not well understood. Large distances, high extinction, and short timescales of critical evolutionary phases make observations of these processes challenging. Lacking good observational guidance, theoretical models have remained controversial. This review offers a basic description of the collapse of a massive molecular core and a critical discussion of the three competing concepts of massive star formation: - monolithic collapse in isolated cores - competitive accretion in a protocluster environment - stellar collisions and mergers in very dense systems We also review the observed outflows, multiplicity, and clustering properties of massive stars, the upper initial mass function and the upper mass limit. We conclude that high-mass star formation is not merely a scaled-up version of low-mass star formation with higher accretion rates, but partly a mechanism of its own, primarily owing to the role of stellar mass and radiation pressure in controlling the dynamics.

Hans Zinnecker; Harold W. Yorke

2007-07-09

271

Propellantless formation flight applications using electromagnetic satellite formations  

NASA Astrophysics Data System (ADS)

The alternative to using propellant for actuation of formation flying satellites is for each spacecraft to produce their own electromagnetic field that others in the formation can react against. This technique can be achieved by creating a steerable magnetic dipole and is called Electromagnetic Formation Flight (EMFF). EMFF can be implemented on a spacecraft by driving current through three orthogonal electromagnetic coils to create a steerable magnetic dipole in three dimensions. This paper investigates the applicability of EMFF as a means for attitude and translation control of multiple spacecraft maneuvering in close proximity. One example scenario is using two EMFF satellites as an inspector system to examine a non-EMFF satellite that is nearby. The results of the analysis show the design of the proximity guidance, navigation, and control laws that allow for rapid inspection scenarios. The primary role of EMFF is to impart forces and torques to maintain a satellite array. In addition, potential secondary roles of EMFF were investigated using EMFF in a multi-role sense. These included power transmission, passive, offensive capabilities, and use of the HTS coils as torque coils for geostationary satellites. The results of this paper show that EMFF is a promising propellantless formation flight technology.

Kwon, Daniel W.

2010-11-01

272

Formation Flying In Highly Elliptical Orbits Initializing the Formation  

NASA Technical Reports Server (NTRS)

In this paper several methods are examined for initializing formations in which all spacecraft start in a common elliptical orbit subsequent to separation from the launch vehicle. The tetrahedron formation used on missions such as the Magnetospheric Multiscale (MMS), Auroral Multiscale Midex (AMM), and Cluster is used as a test bed Such a formation provides full three degrees-of-freedom in the relative motion about the reference orbit and is germane to several missions. The type of maneuver strategy that can be employed depends on the specific initial conditions of each member of the formation. Single-impulse maneuvers based on a Gaussian variation-of-parameters (VOP) approach, while operationally simple and intuitively-based, work only in a limited sense for a special class of initial conditions. These 'tailored' initial conditions are characterized as having only a few of the Keplerian elements different from the reference orbit. Attempts to achieve more generic initial conditions exceed the capabilities of the single impulse VOP. For these cases, multiple-impulse implementations are always possible but are generally less intuitive than the single-impulse case. The four-impulse VOP formalism discussed by Schaub is examined but smaller delta-V costs are achieved in our test problem by optimizing a Lambert solution.

Mailhe, Laurie; Schiff, Conrad; Hughes, Steven

2000-01-01

273

Requirements for Hirano Body Formation  

PubMed Central

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

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

2014-01-01

274

Formation of the first stars  

NASA Astrophysics Data System (ADS)

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.

Bromm, Volker

2013-11-01

275

Formation of the first stars.  

PubMed

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

Bromm, Volker

2013-11-01

276

Cosmic Star-Formation History  

NASA Astrophysics Data System (ADS)

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.

Madau, Piero; Dickinson, Mark

2014-08-01

277

Hydrodynamic Simulations of Galaxy Formation  

E-print Network

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.

A. A. Thoul

1994-12-09

278

Accretion processes in star formation.  

NASA Astrophysics Data System (ADS)

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 is covered at two levels. A descriptive narrative integrating both observational data and theoretical models is accessible to undergraduates or non-specialists. In addition, each topic is given a rigorous theoretical development with comparison to observations, and is appropriate for first-year graduate students.

Hartmann, L.

279

75 FR 81836 - Truth in Lending  

Federal Register 2010, 2011, 2012, 2013

...changes in a tabular format. The Board is issuing...the subject line of the message. Fax: (202) 452-3819...payment, for loans with variable rates or payments. The...disclose in a tabular format the contract interest...18(s) prescribes format and content for...

2010-12-29

280

Chevrons formation in laminar erosion  

NASA Astrophysics Data System (ADS)

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.

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

2007-11-01

281

A standard audit trail format  

SciTech Connect

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.

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

1995-02-01

282

Signal Formation in Various Detectors  

E-print Network

In this write up we present the general theory of the signal formation in various detectors. We follow a pedagogical analysis and presentation such that the results could easily understood and applied by the interested reader to the different detector configurations. We include few applications to gaseous detectors, namely, Monitored Drift Tubes (MDT) and microstrip pattern detector of the micromegas type.

Manolis Dris; Theo Alexopoulos

2014-06-12

283

Amyloid Beta Mediates Memory Formation  

ERIC Educational Resources Information Center

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,…

Garcia-Osta, Ana; Alberini, Cristina M.

2009-01-01

284

Mechanisms of polymeric film formation.  

PubMed

Polymeric films are applied to solid dosage forms for decorative, protective, and functional purposes. These films are generally applied by a spray atomization process, where the polymer is sprayed onto the solid substrate. The mechanism by which films are formed is dependent on whether the polymer is in the dissolved or dispersed state. For solutions, film formation occurs as the solvent evaporates, since the polymer chains are intimately mixed. Film formation from polymeric dispersions, however, requires the coalescence of individual polymer spheres and interpenetration of the polymer chains. Films prepared from polymeric dispersions exhibit a minimum film forming temperature and processing conditions must exceed this temperature in order to form the film. In addition, these systems generally require post-coating storage in temperature and humidity controlled environments to ensure complete polymer coalescence. Incomplete coalescence can lead to significant changes in drug release over time. This review article highlights the basic science principles involved in film formation from both polymeric solutions and dispersions and the variables that influence these film formation processes. PMID:23305867

Felton, Linda A

2013-12-01

285

Formation Of Aldehydes During Ozonation  

Microsoft Academic Search

This study investigated the formation of aldehydes after ozonation of three real and three model waters reconstituted from hydrophobic organic material. The four main aldehyde species formaldehyde, acetaldehyde, glyoxal, and methyl glyoxal were analyzed. Formaldehyde was the dominant species formed as a result of ozonation. The different waters varied greatly with respect to aldehyde production under similar treatment conditions. Studies

Daniel S. Schechter; Philip C. Singer

1995-01-01

286

Cloud formation in substellar atmospheres  

E-print Network

Clouds seem like an every-day experience. But -- do we know how clouds form on brown dwarfs and extra-solar planets? How do they look like? Can we see them? What are they composed of? Cloud formation is an old-fashioned but still outstanding problem for the Earth atmosphere, and it has turned into a challenge for the modelling of brown dwarf and exo-planetary atmospheres. Cloud formation imposes strong feedbacks on the atmospheric structure, not only due to the clouds own opacity, but also due to the depletion of the gas phase, possibly leaving behind a dynamic and still supersaturated atmosphere. I summarise the different approaches taken to model cloud formation in substellar atmospheres and workout their differences. Focusing on the phase-non-equilibrium approach to cloud formation, I demonstrate the inside we gain from detailed micro-physical modelling on for instance the material composition and grain size distribution inside the cloud layer on a Brown Dwarf atmosphere. A comparison study on four different cloud approaches in Brown Dwarf atmosphere simulations demonstrates possible uncertainties in interpretation of observational data.

Christiane Helling

2008-09-26

287

Cloud Formation, Evolution and Destruction  

E-print Network

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

Estalella, Robert

288

Audiences for Contemporary Radio Formats.  

ERIC Educational Resources Information Center

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

Lull, James T.; And Others

289

Brain gangliosides and memory formation  

Microsoft Academic Search

It is generally accepted that the process of molecular facilitation of neuronal circuits by means of stabilization of synaptic contacts represents the structural basis for memory formation. At the distinct zone of synaptic contact the following basic events occur: alterations of the electrical field strength at the outer surface of synaptic membranes, conformational changes of membrane-bound functional proteins (ion channels,

Hinrich Rahmann

1995-01-01

290

Biofilm formation in Streptococcus pneumoniae  

PubMed Central

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

Domenech, Mirian; Garcia, Ernesto; Moscoso, Miriam

2012-01-01

291

Reflexive Expectation Formation Timo Ehrig  

E-print Network

Reflexive Expectation Formation Timo Ehrig J¨urgen Jost Abstract How do economic agents form expectations regarding asset prices and the development of macroeconomic quantities, when of expectations fold back to the realized economic process, and in particular, to the selection of one of multiple

Jost, Jürgen

292

Stereotype Formation: Biased by Association  

ERIC Educational Resources Information Center

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…

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

2010-01-01

293

The Theory of Planetary Formation  

NSDL National Science Digital Library

This website offers an audio of a lecture on the theory of planetary formation. There is also an option to use a viewgraph if you do not have real audio player. The site also provides a detailed written summary of the audio lecture.

Cassen, Patrick

2005-04-25

294

Technology Enhanced Distributive Formative Evaluation  

ERIC Educational Resources Information Center

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

Moore, David Richard

2008-01-01

295

Machining -Chip Formation, Cutting Fluids,  

E-print Network

) continuous chip with large primary shear zone; (d) continuous chip with built-up edge; (e) segmented Discontinuous Continuous Catastrophic 50 100 Built-up edge Chip Shear localized hi Catastrophic shear Complete Prof. J.S. Colton © GIT 2009 10 ­ cracks extend into workpiece #12;Formation of Built up Edge (BUE

Colton, Jonathan S.

296

INTRAMURAL SOCCER RULES League Format  

E-print Network

INTRAMURAL SOCCER RULES League Format All players must complete the Sportsmanship Agreement soccer shoes or non-marking sneakers. Referees The authority of the referees starts upon entering. The team calling the time-out can only do so when their goalkeeper has control of the ball in his/her hands

Paulsson, Johan

297

Formation of the Giant Planets  

Microsoft Academic Search

The structure of a gaseous envelope surrounding a protoplanet has been investigated in connection with the formation of the giant planets. Under the assumptions of spherical symmetry and hydrostatic equilibrium, the structure has been calculated for the regions of Jupiter, Saturn, Uranus and Neptune. Energy transfer in the envelope has been taken into account precisely. When the core mass increases

Hiroshi Mizuno

1980-01-01

298

Informatique Nature de la formation  

E-print Network

opérationnelle, recouvrant ainsi tous les grands domaines de l'Informatique : Algorithmique et Programmation, les structures de données, les bases de données Simuler, expliquer un programme informatique, etInformatique Nature de la formation : Diplôme national de l'Enseignement Supérieur Durée des études

Sart, Remi

299

Tourism motivation and expectation formation  

Microsoft Academic Search

This theoretical study introduces a model of tourism motivation and expectation formation. It is based on a discussion and operationalization of both the behaviorist notion of drive reduction and the cognitivist constructs of attitudes and values. While the satisfaction of inner-directed values and motivations depends on classes of objects, outer-directed values target specific objects. In the case of trying to

Juergen Gnoth

1997-01-01

300

Heteronuclear Diatomic Molecular Orbital Formation  

NSDL National Science Digital Library

Here is a set of movies that demonstrates heteronuclear diatomic molecular orbital formation. The orbitals start at a distance where there is little or no interatomic interaction and move to the appropriate bond distance. Orbital phase is shown by the different colors.

301

The formation of the Galaxy  

Microsoft Academic Search

A simple 'bottom-up' galaxy formation picture is discussed in which the Galaxy fits comfortably as the product of the collapse of material around an average density peak of somewhat less than three sigma amplitude in an initial density field with statistics similar to those expected in the cold dark matter\\/inflation scenario. The model, with the amplitude as the only adjustable

James E. Gunn

1987-01-01

302

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). ...

303

Peripheral Leptin Regulates Bone Formation  

PubMed Central

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

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

2012-01-01

304

Method of fracturing a geological formation  

DOEpatents

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.

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

1990-01-01

305

Mechanisms of plant spindle formation.  

PubMed

In eukaryotes, the formation of a bipolar spindle is necessary for the equal segregation of chromosomes to daughter cells. Chromosomes, microtubules and kinetochores all contribute to spindle morphogenesis and have important roles during mitosis. A unique property of flowering plant cells is that they entirely lack centrosomes, which in animals have a major role in spindle formation. The absence of these important structures suggests that plants have evolved novel mechanisms to assure chromosome segregation. In this review, we highlight some of the recent studies on plant mitosis and argue that plants utilize a variation of "spindle self-organization" that takes advantage of the early polarity of plant cells and accentuates the role of kinetochores in stabilizing the spindle midzone in prometaphase. PMID:21424324

Zhang, Han; Dawe, R Kelly

2011-04-01

306

Formation of quasiparallel Alfven solitons  

NASA Technical Reports Server (NTRS)

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.

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

1992-01-01

307

Engineering biofilm formation and dispersal  

PubMed Central

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

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

2011-01-01

308

Rapid gas hydrate formation process  

DOEpatents

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.

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

2013-01-15

309

Hydrodynamics of catheter biofilm formation  

E-print Network

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.

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

2009-01-01

310

Protein engineering of formate dehydrogenase  

Microsoft Academic Search

NAD+-dependent formate dehydrogenase (FDH, EC 1.2.1.2) is one of the best enzymes for the purpose of NADH regeneration in dehydrogenase-based synthesis of optically active compounds. Low operational stability and high production cost of native FDHs limit their application in commercial production of chiral compounds. The review summarizes the results on engineering of bacterial and yeast FDHs aimed at improving their

Vladimir I. Tishkov; Vladimir O. Popov

2006-01-01

311

Contrail formation in aircraft wakes  

Microsoft Academic Search

The process of the formation and early evolution of a condensation trail (`contrail') in the near field of an aircraft wake was numerically studied by means of a mixed Eulerian\\/Lagrangian two-phase flow approach. Large-eddy simulations were used for the carrier phase, while, for the dispersed phase, a Lagrangian particle tracking method was used, coupled with a microphysics model to account

Roberto Paoli; Jerome Hélie; Thierry Poinsot

2004-01-01

312

Kinetic models of opinion formation  

E-print Network

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.

G. Toscani

2006-05-17

313

Pyrazines: occurrence, formation and biodegradation  

Microsoft Academic Search

Pyrazines are a class of compounds that occur almost ubiquitously in nature. Pyrazines can be synthesised chemically or biologically,\\u000a and are used as flavouring additives. The major formation of pyrazines occurs during heating of food. There is very little\\u000a information available on the degradation of these compounds. In humans and animals, pyrazines are excreted as glucuronates\\u000a or bound to glutathione

Rudolf Müller; Sugima Rappert

2010-01-01

314

Photophoresis boosts giant planet formation  

NASA Astrophysics Data System (ADS)

In the core accretion model of giant planet formation, a solid protoplanetary core begins to accrete gas directly from the nebula when its mass reaches ~5 M?. The protoplanet has at most a few million years to reach runaway gas accretion, as young stars lose their gas disks after 10 million years at the latest. Yet gas accretion also brings small dust grains entrained in the gas into the planetary atmosphere. Dust accretion creates an optically thick protoplanetary atmosphere that cannot efficiently radiate away the kinetic energy deposited by incoming planetesimals. A dust-rich atmosphere severely slows down atmospheric cooling, contraction, and inflow of new gas, in contradiction to the observed timescales of planet formation. Here we show that photophoresis is a strong mechanism for pushing dust out of the planetary atmosphere due to the momentum exchange between gas and dust grains. The thermal radiation from the heated inner atmosphere and core is sufficient to levitate dust grains and to push them outward. Photophoresis can significantly accelerate the formation of giant planets.

Teiser, J.; Dodson-Robinson, S. E.

2013-07-01

315

Rock Cycle: Environments of Formation  

NSDL National Science Digital Library

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.

National Science Teachers Association (NSTA)

2006-11-01

316

SCALE FORMATION IN CHRYSOPHYCEAN ALGAE  

PubMed Central

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

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

1970-01-01

317

The Formation of Close Binaries  

NASA Astrophysics Data System (ADS)

Binary stars produce an array of dramatic astrophysical phenomena. They allow us to probe stellar structure, nuclear physics, and gravitational wave physics. They also produce the powerful supernovae that allow us to measure the scale of the universe. Despite their importance and ubiquity, many questions remain unanswered as to how the star formation process produces the wide array of stellar multiples that we observe. A complete model for binary formation encompasses three main components. We must know: (1) the primordial population of systems, (2) the influence of the dynamical processes that reshape this distribution as stars form and natal clusters disperse, and (3) the role of binary stellar evolution. In this article, I review the most prominent theories for binary formation: turbulent core fragmentation, disc fragmentation, and competitive accretion. I argue that turbulent core fragmentation at all masses, with disc fragmentation added in at the upper end of the mass spectrum, might explain the trend towards increasing multiplicity for higher mass stars. In addition, I provide a brief overview of the observational statistics and of some of the important processes that modify the primordial distribution of stellar orbits.

Kratter, K. M.

2011-09-01

318

Gravity, Turbulence, and Star Formation  

NASA Astrophysics Data System (ADS)

The azimuthal power spectra of optical emission from star formation and dust in spiral galaxies resembles the azimuthal power spectra of HI emission from the LMC. These and other power spectra of whole galaxies all resemble that of velocity in incompressible Kolmogorov turbulence. The reasons for this are unknown but it could be simply that star and cloud formation are the result of a mixture of processes and each gives a power spectrum similar to Kolmogorov turbulence, within the observable errors. The important point is that star and cloud formation are not random but are correlated over large distances by forces that span several orders of magnitude in scale. These forces are probably the usual combination of self-gravity, turbulence, and compression from stellar winds and supernovae, but they have to work in concert to create the structures we see in galaxies. In addition, the identification of flocculant spirals with swing amplified instabilities opens the possibility that a high fraction of turbulence in the ISM is the result of self-gravity.

Elmegreen, B.

2004-12-01

319

Formation of Outer Planets: Overview  

NASA Technical Reports Server (NTRS)

An overview of current theories of planetary formation, with emphasis on giant planets is presented. The most detailed models are based upon observation of our own Solar System and of young stars and their environments. Terrestrial planets are believe to grow via pairwise accretion until the spacing of planetary orbits becomes large enough that the configuration is stable for the age of the system. According to the prevailing core instability model, giant planets begin their growth by the accumulation of small solid bodies, as do terrestrial planets. However, unlike terrestrial planets, the growing giant cores become massive enough that they are able to accumulate substantial amounts of gas before the protoplanetary disk disspates. The primary questions regarding the core instability model is whether planets with small cores can accrete gaseous enveloples within the lifetimes of gaseous protoplanetary disks. The main alternative giant planet formation model is the disk instability model, in which gaseous planets form directly via gravitational instabilities within protoplanetary disks. Formation of giant planets via gas instability has never been demonstrated for realistic disk conditions. Moreover, this model has difficulty explaining the supersolar abundances of heavy elements in Jupiter and Saturn, and it does not explain the orgin of planets like Uranus and Neptune.

Lissauer, Jack

2003-01-01

320

Formation mechanisms of metal colloids  

NASA Astrophysics Data System (ADS)

Highly dispersed uniform metallic particles are widely used in various areas of technology and medicine and are likely to be incorporated into many other applications in the future. It is commonly accepted that size, shape and composition of the particles represent critical factors in most applications. Thus, understanding the mechanisms of formation of metal particles and the ways to control the physical (e.g. shape, size) and chemical (e.g. composition) properties is of great importance. In the current research, the formation of uniform silver spheres is investigated experimentally. The parameters that influence the formation of silver particles when concentrated iso-ascorbic acid and silver-polyamine complex solutions are rapidly mixed were studied in the absence of dispersants. We found that by varying the nature of the amine, temperature, concentration of reactants, silver/amine molar ratio, and the nature of the silver salt, the size of the resulting silver particles can be varied in a wide range (0.08--1.5 microm). The silver particles were formed by aggregation of nanosize subunits as substantiated by both electron microscopy and X-ray diffraction techniques and by the vivid rapid color changes during the chemical precipitation process. From the practical standpoint, the goal of this research was to prepare well dispersed spherical silver particles having a relatively smooth surface and a diameter of about 1 microm to satisfy the demands of the current electronic materials market. A two stage particle growth model previously developed to explain the narrow size distribution occurring in synthesis of gold spheres was applied to the present experimental system, and the parameters that control the size distribution characteristics were identified. The kinetic parameter required to match the final particle size was found to be in agreement with the one used previously in modeling formation of gold spheres, suggesting that similar kinetics governs the aggregation process. Furthermore, the two-stage particle growth model was used to account for the effects of solvent viscosity and temperature on the particle properties, particularly their size. As an application of the above mentioned study, the aggregation process that led to the formation of large silver spheres was used to deposit in a controlled manner layers of silver and other metals (Ni, Au) onto various metallic and non-metallic substrates. In the final section of this thesis methods to form nanosized primary particle strictly through diffusional growth are described. The highly crystalline metallic particles of various sizes and composition prepared provide performance characteristics that are complementary to the polycrystalline metallic particles described in the preceding sections.

Halaciuga, Ionel

321

Core formation in silicate bodies  

NASA Astrophysics Data System (ADS)

Differentiation of a body into a metallic core and silicate mantle occurs most efficiently if temperatures are high enough to allow at least the metal to melt [1], and is enhanced if matrix deformation occurs [2]. Elevated temperatures may occur due to either decay of short-lived radio-isotopes, or gravitational energy release during accretion [3]. For bodies smaller than the Moon, core formation happens primarily due to radioactive decay. The Hf-W isotopic system may be used to date core formation; cores in some iron meteorites and the eucrite parent body (probably Vesta) formed within 1 My and 1-4~My of solar system formation, respectively [4]. These formation times are early enough to ensure widespread melting and differentiation by 26Al decay. Incorporation of Fe60 into the core, together with rapid early mantle solidification and cooling, may have driven early dynamo activity on some bodies [5]. Iron meteorites are typically depleted in sulphur relative to chondrites, for unknown reasons [6]. This depletion contrasts with the apparently higher sulphur contents of cores in larger planetary bodies, such as Mars [7], and also has a significant effect on the timing of core solidification. For bodies of Moon-size and larger, gravitational energy released during accretion is probably the primary cause of core formation [3]. The final stages of accretion involve large, stochastic collisions [8] between objects which are already differentiated. During each collision, the metallic cores of the colliding objects merge on timescales of a few hours [9]. Each collision will reset the Hf-W isotopic signature of both mantle and core, depending on the degree to which the impactor core re-equilibrates with the mantle of the target [10]. The re-equilibration efficiency depends mainly on the degree to which the impactor emulsifies [11], which is very uncertain. Results from N-body simulations [8,12] suggest that significant degrees of re- equilibration are required [4,10]. Re-equilibration is also suggested by mantle siderophile abundances [13], though simple partitioning models do not capture the likely complex P,T evolution during successive giant impacts. The timescale of Martian core formation is currently uncertain (0-10 My) [14], though it is clear that Martian core formation ended before that of the Earth. [1] Stevenson, in Origin of the Earth, 1990. [2] Groebner and Kohlstedt, EPSL 2006. [3] Rubie et al., Treatise Geophys. 2007. [4] Kleine et al., GCA submitted. [5] Weiss et al., LPSC 39, 2008. [6] Keil and Wilson, EPSL 1993 [7] Wanke and Dreibus, PTRSL, 1984. [8] Agnor et al. Icarus 1999 [9] Canup and Asphaug, Nature 2001 [10] Nimmo and Agnor, EPSL 2006. [11] Rubie et al., EPSL 2003 [12] O'Brien et al, Icarus 2006 [13] Righter, AREPS 2003. [14] Nimmo and Kleine, Icarus 2007.

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

2008-12-01

322

Process for stabilizing rock and coal formations by bonding these formations to themselves or other geological formations  

Microsoft Academic Search

The invention relates to a process for stabilizing rock and coal formations by bonding them to each other or to other geological formations. The bonding material is a reactive organic polyisocyanate-polyol mixture which may contain a catalyst.

D. Arndt; D. Hobein

1984-01-01

323

On-Going Galaxy Formation  

NASA Astrophysics Data System (ADS)

We investigate the process of galaxy formation as can be observed in the only currently forming galaxies - the so-called Tidal Dwarf Galaxies, hereafter TDGs - through observations of the molecular gas detected via its CO (Carbon Monoxide) emission. These objects are formed of material torn off of the outer parts of a spiral disk due to tidal forces in a collision between two massive galaxies. Molecular gas is a key element in the galaxy formation process, providing the link between a cloud of gas and a bona fide galaxy. We have detected CO in 8 TDGs (Braine, Lisenfeld, Duc and Leon, 2000: Nature 403, 867; Braine, Duc, Lisenfeld, Charmandaris, Vallejo, Leon and Brinks: 2001, A&A 378, 51), with an overall detection rate of 80%, showing that molecular gas is abundant in TDGs, up to a few 108 M ?. The CO emission coincides both spatially and kinematically with the HI emission, indicating that the molecular gas forms from the atomic hydrogen where the HI column density is high. A possible trend of more evolved TDGs having greater molecular gas masses is observed, in accord with the transformation of HI into H2. Although TDGs share many of the properties of small irregulars, their CO luminosity is much greater (factor ˜ 100) than that of standard dwarf galaxies of comparable luminosity. This is most likely a consequence of the higher metallicity (?sim 1/3 solar) of TDGs which makes CO a good tracer of molecular gas. This allows us to study star formation in environments ordinarily inaccessible due to the extreme difficulty of measuring the molecular gas mass. The star formation efficiency, measured by the CO luminosity per H? flux, is the same in TDGs and full-sized spirals. CO is likely the best tracer of the dynamics of these objects because some fraction of the HI near the TDGs may be part of the tidal tail and not bound to the TDG. Although uncertainties are large for individual objects, as the geometry is unknown, our sample is now of eight detected objects and we find that the ‘dynamical’ masses of TDGs, estimated from the CO line widths, seem not to be greater than the ‘visible’ masses (HI + H2 + a stellar component). Although higher spatial resolution CO (and HI) observations would help reduce the uncertainties, we find that TDGs require no dark matter, which would make them the only galaxy-sized systems where this is the case. Dark matter in spirals should then be in a halo and not a rotating disk. Most dwarf galaxies are dark matter-rich, implying that they are not of tidal origin. We provide strong evidence that TDGs are self-gravitating entities, implying that we are witnessing the ensemble of processes in galaxy formation: concentration of large amounts of gas in a bound object, condensation of the gas, which is atomic at this point, to form molecular gas and the subsequent star formation from the dense molecular component.

Braine, Jonathan; Duc, P.-A.; Lisenfeld, U.; Charmandaris, V.; Vallejo, O.; Leon, S.; Brinks, E.

2002-07-01

324

Sequential star formation in Cassiopeia  

NASA Astrophysics Data System (ADS)

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.

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

2013-05-01

325

Pattern formation in geochemical systems  

NASA Astrophysics Data System (ADS)

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

Katsev, Sergei

2002-08-01

326

Formation Flying and Deformable Instruments  

SciTech Connect

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

Rio, Yvon [CEA/IRFU/Sap, CEA Saclay, 91191 Gif sur Yvette (France)

2009-05-11

327

Formation Flying and Deformable Instruments  

NASA Astrophysics Data System (ADS)

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

Rio, Yvon

2009-05-01

328

The formation of interstellar jets  

NASA Technical Reports Server (NTRS)

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

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

1988-01-01

329

Biomimetic stereoselective formation of methyllanthionine.  

PubMed

Fmoc-(2R,3S)-3-methyl-Se-phenylselenocysteine was used for the synthesis of dehydrobutyrine (Dhb)-containing peptides. Biomimetic cyclization via Michael addition of Cys to a Dhb yielded the B-ring of the lantibiotic subtilin as a single diastereomer. The methyllanthionine product was shown to have the natural configuration by preparation of the authentic stereoisomer. The formation of a single isomer suggests that the prepeptide has a strong intrinsic preference for the stereochemistry observed in lantibiotics. [reaction: see text] PMID:11950356

Zhou, Hao; van der Donk, Wilfred A

2002-04-18

330

Percolation-induced frost formation  

NASA Astrophysics Data System (ADS)

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.

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

2013-01-01

331

Dark Matter and Galaxy Formation  

E-print Network

Abstract. The four lectures that I gave in the XIII Ciclo de Cursos Especiais at the National Observatory of Brazil in Rio in October 2008 were (1) a brief history of dark matter and structure formation in a ?CDM universe; (2) challenges to ?CDM on small scales: satellites, cusps, and disks; (3) data on galaxy evolution and clustering compared with simulations; and (4) semi-analytic models. These lectures, themselves summaries of much work by many people, are summarized here briefly. The slides [1] contain much more information.

Joel R. Primack A

332

Dust formation by failed supernovae  

NASA Astrophysics Data System (ADS)

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.

Kochanek, C. S.

2014-11-01

333

Transcriptional regulation in wood formation.  

PubMed

Wood (i.e. xylem tissue) in trees is mainly composed of two types of cells, fibres and tracheary elements. Recent molecular studies of various trees, as well as the non-tree species Arabidopsis thaliana and Zinnia elegans, have revealed coordinated gene expression during differentiation of these cells in wood and the presence of several transcription factors that might govern the complex networks of transcriptional regulation. This article reviews recent findings concerning the regulation of genes by transcription factors involved in wood formation such as AUXIN RESPONSE FACTOR (ARF), CLASS III HOMEODOMAIN-LEUCINE ZIPPER (HD-ZIPIII), KANADI (KAN), MYB and NAM/ATAF/CUC (NAC). PMID:17224301

Demura, Taku; Fukuda, Hiroo

2007-02-01

334

Zonal flow as pattern formation  

SciTech Connect

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.

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

335

Electrochemical formation of field emitters  

DOEpatents

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.

Bernhardt, Anthony F. (Berkeley, CA)

1999-01-01

336

49 CFR 563.8 - Data format.  

Code of Federal Regulations, 2011 CFR

...Transportation 6 2011-10-01 2011-10-01 false Data format. 563.8 Section 563.8 Transportation...ADMINISTRATION, DEPARTMENT OF TRANSPORTATION EVENT DATA RECORDERS § 563.8 Data format. Link to an amendment published at...

2011-10-01

337

49 CFR 563.8 - Data format  

Code of Federal Regulations, 2010 CFR

...Transportation 6 2010-10-01 2010-10-01 false Data format 563.8 Section 563.8 Transportation...ADMINISTRATION, DEPARTMENT OF TRANSPORTATION EVENT DATA RECORDERS § 563.8 Data format (a) The data elements listed in...

2010-10-01

338

49 CFR 563.8 - Data format.  

Code of Federal Regulations, 2013 CFR

...Transportation 6 2013-10-01 2013-10-01 false Data format. 563.8 Section 563.8 Transportation...ADMINISTRATION, DEPARTMENT OF TRANSPORTATION EVENT DATA RECORDERS § 563.8 Data format. (a) The data elements listed...

2013-10-01

339

Formation of the terrestrial planets from planetesimals  

NASA Technical Reports Server (NTRS)

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.

Wetherill, George W.

1991-01-01

340

XML Format for SESAME and LEOS  

SciTech Connect

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.

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

2009-04-29

341

Formation damage in underbalanced drilling operations  

E-print Network

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...

Reyes Serpa, Carlos Alberto

2012-06-07

342

48 CFR 1315.204 - Contract format.  

Code of Federal Regulations, 2010 CFR

... CONTRACTING BY NEGOTIATION Solicitation and Receipt of Proposals and Information 1315.204 Contract format. The designee authorized to grant exemptions from the uniform contract format is set forth in CAM...

2010-10-01

343

48 CFR 1315.204 - Contract format.  

Code of Federal Regulations, 2011 CFR

... CONTRACTING BY NEGOTIATION Solicitation and Receipt of Proposals and Information 1315.204 Contract format. The designee authorized to grant exemptions from the uniform contract format is set forth in CAM...

2011-10-01

344

29 CFR 1960.38 - Committee formation.  

Code of Federal Regulations, 2012 CFR

... 2012-07-01 false Committee formation. 1960.38 Section 1960.38 Labor Regulations Relating to Labor (Continued...MATTERS Occupational Safety and Health Committees § 1960.38 Committee formation. (a) Upon...

2012-07-01

345

29 CFR 1960.38 - Committee formation.  

Code of Federal Regulations, 2011 CFR

... 2011-07-01 false Committee formation. 1960.38 Section 1960.38 Labor Regulations Relating to Labor (Continued...MATTERS Occupational Safety and Health Committees § 1960.38 Committee formation. (a) Upon...

2011-07-01

346

29 CFR 1960.38 - Committee formation.  

Code of Federal Regulations, 2010 CFR

... 2010-07-01 false Committee formation. 1960.38 Section 1960.38 Labor Regulations Relating to Labor (Continued...MATTERS Occupational Safety and Health Committees § 1960.38 Committee formation. (a) Upon...

2010-07-01

347

Dynamics and control of electromagnetic satellite formations  

E-print Network

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 ...

Ahsun, Umair, 1972-

2007-01-01

348

Structure formation: Models, Dynamics and Status  

E-print Network

The constraints on the models for the structure formation arising from various cosmological observations at different length scales are reviewed. The status of different models for structure formation is examined critically in the light of these observations.

T. Padmanabhan

1995-08-25

349

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.

350

External Resource: The Formation of the Moon  

NSDL National Science Digital Library

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.

1900-01-01

351

Beaver assisted river valley formation  

USGS Publications Warehouse

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.

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

2011-01-01

352

Possible mechanisms of macrolayer formation  

SciTech Connect

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

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

1992-05-01

353

Possible mechanisms of macrolayer formation  

SciTech Connect

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

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

1992-01-01

354

Tube Formation in Nanoscale Materials  

PubMed Central

The formation of tubular nanostructures normally requires layered, anisotropic, or pseudo-layered crystal structures, while inorganic compounds typically do not possess such structures, inorganic nanotubes thus have been a hot topic in the past decade. In this article, we review recent research activities on nanotubes fabrication and focus on three novel synthetic strategies for generating nanotubes from inorganic materials that do not have a layered structure. Specifically, thermal oxidation method based on gas–solid reaction to porous CuO nanotubes has been successfully established, semiconductor ZnS and Nb2O5nanotubes have been prepared by employing sacrificial template strategy based on liquid–solid reaction, and an in situ template method has been developed for the preparation of ZnO taper tubes through a chemical etching reaction. We have described the nanotube formation processes and illustrated the detailed key factors during their growth. The proposed mechanisms are presented for nanotube fabrication and the important pioneering studies are discussed on the rational design and fabrication of functional materials with tubular structures. It is the intention of this contribution to provide a brief account of these research activities. PMID:20592945

2008-01-01

355

Montezuma Formation of Costa Rica  

SciTech Connect

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.

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

1985-01-01

356

Globular Cluster Formation in Mergers  

E-print Network

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 <10% of all stars formed in the starbursts. The most massive young 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.

Francois Schweizer

2006-06-01

357

Cooper Pair Formation in Acenes  

NASA Astrophysics Data System (ADS)

We have measured the ratio of doubly to singly charged molecular parent ions of benzene, naphthalene, anthracene, and pyrrole over a wide range of photon energies. About 40 eV above the double-ionization threshold, the first three of the above molecules exhibit a hump of very similar shape and magnitude in the double-to-single photoionization ratio, which we attribute to the formation and emission of an electron Cooper pair from a free molecule. Our results suggest that the de Broglie wave of this highly correlated pair of electrons forms a closed loop in the system of overlapping ? bonds with a wavelength that matches the distance between neighboring carbon atoms. Pyrrole with its pentagonal structure does not allow the formation of a closed de Broglie wave and, thus, does not exhibit a hump in the ratio. Photoelectron measurements indicate the break-up of the emitted Cooper pair by two electron peaks sitting on top of the mainly U-shaped double-ionization continuum in support of our interpretation.

Hartman, Tim; Jurani?, Pavle; Collins, Kelly; Reilly, Bethany; Appathurai, Narayana; Whitfield, Scott B.; Wehlitz, Ralf

2012-06-01

358

Virialization Heating in Galaxy Formation  

SciTech Connect

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.

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

2007-01-17

359

Dilatational band formation in bone  

PubMed Central

Toughening in hierarchically structured materials like bone arises from the arrangement of constituent material elements and their interactions. Unlike microcracking, which entails micrometer-level separation, there is no known evidence of fracture at the level of bone’s nanostructure. Here, we show that the initiation of fracture occurs in bone at the nanometer scale by dilatational bands. Through fatigue and indentation tests and laser confocal, scanning electron, and atomic force microscopies on human and bovine bone specimens, we established that dilatational bands of the order of 100 nm form as ellipsoidal voids in between fused mineral aggregates and two adjacent proteins, osteocalcin (OC) and osteopontin (OPN). Laser microdissection and ELISA of bone microdamage support our claim that OC and OPN colocalize with dilatational bands. Fracture tests on bones from OC and/or OPN knockout mice (OC?/?, OPN?/?, OC-OPN?/?;?/?) confirm that these two proteins regulate dilatational band formation and bone matrix toughness. On the basis of these observations, we propose molecular deformation and fracture mechanics models, illustrating the role of OC and OPN in dilatational band formation, and predict that the nanometer scale of tissue organization, associated with dilatational bands, affects fracture at higher scales and determines fracture toughness of bone. PMID:23129653

Poundarik, Atharva A.; Diab, Tamim; Sroga, Grazyna E.; Ural, Ani; Boskey, Adele L.; Gundberg, Caren M.; Vashishth, Deepak

2012-01-01

360

String Formatting Considered Harmful for Novice Programmers  

ERIC Educational Resources Information Center

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…

Hughes, Michael C.; Jadud, Matthew C.; Rodrigo, Ma. Mercedes T.

2010-01-01

361

A new PICL trace file format  

SciTech Connect

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.

Worley, P.H.

1992-10-01

362

FAINT RADIO SOURCES AND STAR FORMATION HISTORY  

E-print Network

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

Waddington, Ian

363

Cyclic Steam Stimulation With Formation Parting  

Microsoft Academic Search

Cyclic steam stimulation in highly viscous oil-bearing formations, such as those of Cold Lake, entails formation parting in many cases. This work presents a numeric treatment of the phenomena involved in this process, viz., fluid flow in cyclic steam stimulation, formation parting, fracture propagation, and closure. The latter part of the model involves the calculation of stresses and strains in

S. M. Farouq. Ali; J. Blunschi

1983-01-01

364

Transfer of Training with Formation Flight Trainer.  

ERIC Educational Resources Information Center

The present research was conducted to determine transfer of practice from a formation simulator to actual aircraft flight for the wing aircraft component of the formation flying task. Evidence in support of positive transfer was obtained by comparing students trained in the formation simulator with students who were essentially untrained and with…

Reid, Gary B.; Cyrus, Michael L.

365

Formative Constructs Implemented via Common Factors  

ERIC Educational Resources Information Center

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…

Treiblmaier, Horst; Bentler, Peter M.; Mair, Patrick

2011-01-01

366

Star formation and the ages of stars  

NASA Astrophysics Data System (ADS)

In this contribution we illustrate how the knowledge of the ages of stars is important to constrain star formation processes. We focus on two specific cases: star formation around the supermassive black hole at the center of the Galaxy and triggered star formation on the borders of Hii regions.

Martins, F.

2014-11-01

367

Genome organization and species formation in vertebrates  

Microsoft Academic Search

Some years ago Wilson and co-workers proposed that the higher rates of karyotypic change and species formation of mammals compared to cold-blooded vertebrates are due to the formation of small demes, as favored by the social structuring and brain development of the former. Here, evidence is reviewed which indicates that mammals are more prone to karyotypic change and species formation

Giorgio Bernardi

1993-01-01

368

Surfactant effects on gas hydrate formation  

Microsoft Academic Search

Micellar solutions were found to increase gas hydrate formation rate and alter formation mechanism for ethane and natural gas hydrates. A critical micellar concentration (CMC) of sodium dodecyl sulfate water solution was found to be 242 ppm at hydrate-forming conditions, where CMC was best determined by hydrate induction time. At surfactant concentrations above the CMC, hydrate formation rates in a

Y. Zhong; R. E. Rogers

2000-01-01

369

A new PICL trace file format  

Microsoft Academic Search

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.

P. H. Worley

1992-01-01

370

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

371

Experimental adipocere formation: implications for adipocere formation on buried bone.  

PubMed

Adipocere, or grave wax (adipo = fat, cere = wax), is a distinctive decomposition product composed primarily of fatty acids (FA) and their alkali salts. FA result from the bacterial enzymatic hydrolysis of body fats. Reactions with ammonia and alkali metals originating from body fluids and pore waters of the depositional environment produce alkali salts of FA (soap). Adipocere formation is generally associated with burial of corpses with ample adipose tissue available. No indications that adipocere can form on defleshed remains have been presented in the literature. At the termination of a long-term bone diagenesis experiment, several samples were found to possess growths of an unknown compound. Gas chromatography-mass spectrometry confirmed that the growths are adipocere. The results herein reveal that adipocere can indeed form on defleshed bones under the right conditions and that even residual adipose and lipids in defleshed bones are sufficient to produce adipocere growth on the surfaces of bone. PMID:22211839

Moses, Randolph J

2012-05-01

372

Early planet formation as a trigger for further planet formation  

E-print Network

Recent discoveries of extrasolar planets at small orbital radii, or with significant eccentricities, indicate that interactions between massive planets and the disks of gas and dust from which they formed are vital for determining the final shape of planetary systems. We show that if this interaction occurs at an early epoch, when the protoplanetary disc was still massive, then rapid planet growth through accretion causes an otherwise stable disc to fragment into additional planetary mass bodies when the planetary mass reaches 4-5 Jupiter masses. We suggest that such catastrophic planet formation could account for apparent differences in the mass function of massive planets and brown dwarfs, and the existence of young stars that appear to have dissipated their discs at an early epoch. Subsequent gravitational interactions will lead to planetary systems comprising a small number of massive planets in eccentric orbits.

Philip J. Armitage; Brad M. S. Hansen

1999-12-08

373

Heating tar sands formations while controlling pressure  

DOEpatents

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.

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

2010-01-12

374

Reversible in situ catalyst formation.  

PubMed

Acid catalysts play a vital role in the industrial synthesis and production of a plethora of organic chemicals. But, their subsequent neutralization and disposal is also a giant source of waste. For example, for a Friedel-Crafts acylation with AlCl 3, a kilogram of product yields up to 20 kg of (contaminated) waste salt. Other processes are even worse, and this waste is both an environmental and economic shortcoming. Here we address this issue by showing a series of acid catalysts where the neutralization is "built in" to the system and thus eliminates waste. Clearly these will not replace all organic and mineral acid catalysts, but they can replace many. Further, we show how these self-neutralizing catalysts can often eliminate unwanted byproducts, improve selectivity, or elimination of mass transfer limitations by changing from heterogeneous to homogeneous systems. They readily facilitate separations and promote recycling, to promote both green chemistry and good economics. First is near-critical water, or liquid water under pressure, where the K W for dissociation goes up 3-4 decades between 0 degrees C and 250 degrees C, thus facilitating both acid and base catalysis. Moreover, as the exothermic hydrogen bonding diminishes, the dielectric constant goes down to the point at which both salts and organics are soluble in this very hot water. For example, toluene and water are completely miscible at 305 degrees C. This eliminates mass transfer limitations for the reactions, and postreaction cooling not only lowers the K W to neutralize the ions without waste but also results in facile separations from simple liquid-liquid immiscibility. Further, we show the formation of catalysts with alkylcarbonic acids from alcohols and CO2, analogous to carbonic acid from water and CO2. We show a number of applications for these self-neutralizing catalysts, including the formation of ketals, the formation of diazonium intermediates to couple with electron-rich aromatics to produce dye molecules, and the hydration of beta-pinene. Here also these systems often enhance phase behavior to cut mass transfer resistance. In an analogous application we show that peroxide and CO2 gives peroxycarbonic acid, also reversible upon the removal of the CO2, and we show application to epoxidation reactions. The bottom line is that these catalysts afford profound advantages for both green chemistry and improved economics. The methods outlined here have potential for abundant applications, and we hope that this work will motivate such opportunities. PMID:18251512

Hallett, Jason P; Pollet, Pamela; Liotta, Charles L; Eckert, Charles A

2008-03-01

375

Seismic Monitoring of Fracture Formation  

NASA Astrophysics Data System (ADS)

Seismically tracking fracture formation is an important step in the monitoring of subsurface sequestration reservoirs. In this paper we report on laboratory experiments that were performed to investigate seismic transmission across a slowly propagating fracture to monitor how fracture heterogeneity varied due to changing stress conditions. Experiments were performed on a cube of Pierre Blue limestone with dimensions 0.3 m by 0.3 m by 0.3 m in a tri-axial pressure machine consisting of three independent loading frames. Two seismic arrays were used to propagate compressional and shear waves through the sample prior to, during, and after fracturing. Each array was composed of sixteen piezoelectric transducers (eight compressional-mode and eight shear-mode) with a central frequency of 1 MHz. After the sample was removed from the triaxial frame, a laser profilometer was used to measure the geometry of the fracture surfaces. The seismic array data produced a time-dependent two-dimensional map of the propagating fracture tip and the resulting fracture. The transmitted signals showed a 5%-10% increase in amplitude as a precursor to the main fracturing event after which the transmitted energy decreased to 1%-15% of its original value. The observed increase in amplitude prior to major failure is caused by constructive interference from diffraction from the tip of the fracture before the fracture tip was even under the sensors. Numerical simulation shows that the precursory increase in amplitude is a function of the specific stiffness of the fracture tip and the frequency of the signal. Post-fracturing characterization of the fracture topology identified anisotropic features in the fracture aperture that correlated with the direction of fracture propagation observed in the seismic data. The seismic signal, combined with the fracture characterization, supports the hypothesis that seismic signals can provide specific information about fracture formation and the resulting fracture geometry. This work demonstrates the potential for developing seismic methods for characterizing time-dependent fracture formation and fracture properties. Acknowledgments: LJPN wishes to acknowledge the Geosciences Research Program, Office of Basic Energy Sciences US Department of Energy, the University Faculty Scholar program at Purdue University, and the Delft University of Technology

Pyrak-Nolte, L. J.; de Pater, C. J.; Jocker, J.

2005-12-01

376

Formation of Coronal Shock Waves  

NASA Astrophysics Data System (ADS)

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.

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

2013-09-01

377

Mud Volcanoes Formation And Occurrence  

NASA Astrophysics Data System (ADS)

Mud volcanoes are natural phenomena, which occur throughout the globe. They are found at a greater or lesser scale in Azerbaijan, Turkmenistan, Georgia, on the Kerch and Taman peninsulas, on Sakhalin Island, in West Kuban, Italy, Romania, Iran, Pakistan, India, Burma, China, Japan, Indonesia, Malaysia, New Zealand, Mexico, Colombia, Trinidad and Tobago, Venezuela and Ecuador. Mud volcanoes are most well-developed in Eastern Azerbaijan, where more than 30% of all the volcanoes in the world are concentrated. More than 300 mud volcanoes have already been recognized here onshore or offshore, 220 of which lie within an area of 16,000 km2. Many of these mud volcanoes are particularly large (up to 400 m high). The volcanoes of the South Caspian form permanent or temporary islands, and numerous submarine banks. Many hypotheses have been developed regarding the origin of mud volcanoes. Some of those hypotheses will be examined in the present paper. Model of spontaneous excitation-decompaction (proposed by Ivanov and Guliev, 1988, 2002). It is supposed that one of major factors of the movement of sedimentary masses and formation of hydrocarbon deposits are phase transitions in sedimentary basin. At phase transitions there are abnormal changes of physical and chemical parameters of rocks. Abnormal (high and negative) pressure takes place. This process is called as excitation of the underground environment with periodicity from several tens to several hundreds, or thousand years. The relationship between mud volcanism and the generation of hydrocarbons, particularly methane, is considered to be a critical factor in mud volcano formation. At high flow rates the gas and sediment develops into a pseudo-liquid state and as flow increases the mass reaches the "so-called hover velocity" where mass transport begins. The mass of fluid moves as a quasi-uniform viscous mass through the sediment pile in a piston like manner until expelled from the surface as a "catastrophic eruption". Model of buoyancy drive (by Brown, 1990). Brown's basic hypothesis is similar to Ivanov and Guliev and may be summarized briefly as follows: -in situations where rapid sedimentation is occurring mud may be driven to the surface by buoyancy forces due to bulk density contrasts between mud and overlying sediment cover. Such density contrasts may be simply the result of compaction -disequilibrium, but more importantly may be related to gas expansion when fluids are transported to shallower depths with lower pressure and temperature conditions. Synthetic model had been proposed by I.Lerche, E.Bagirov, I.Guliyev (1997). The model includes the following studies: The starting point of the mud volcanoes begins with the formation of a zone of decompaction as a consequence of a high rate of gas generation. The mud body starts to rise under buoyancy. The excess pressure inside the mud intrusion is less than in surrounding formation. As a result, fluid flow toward the body of mud volcanoes. The body of the mud volcanoes then grows, increasing the buoyancy forces, with further drive the mud. If the rate of gas generation more thôn gas flow, causing exsolving of gas to free-phase gas. If there are open faults and fractures which cross the body of mud volcanoes, then gas and mud can penetrate through the faults, and so from gryphons and salses on the surface. A mud volcanoes can be consider as a huge accumulation of gas, where as the oil is concentrated on the flanks of the mud body.

Guliyev, I. S.

2007-12-01

378

The Science of Galaxy Formation  

NASA Astrophysics Data System (ADS)

Our knowledge of the Universe remains discovery-led: in the absence of adequate physics-based theory, interpretation of new results requires a scientific methodology. Commonly, scientific progress in astrophysics is motivated by the empirical success of the “Copernican Principle”, that the simplest and most objective analysis of observation leads to progress. A complementary approach tests the prediction of models against observation. In practise, astrophysics has few real theories, and has little control over what we can observe. Compromise is unavoidable. Advances in understanding complex non-linear situations, such as galaxy formation, require that models attempt to isolate key physical properties, rather than trying to reproduce complexity. A specific example is discussed, where substantial progress in fundamental physics could be made with an ambitious approach to modelling: simulating the spectrum of perturbations on small scales.

Gilmore, Gerard

2009-03-01

379

Combuster. [low nitrogen oxide formation  

NASA Technical Reports Server (NTRS)

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.

Mckay, R. A. (inventor)

1978-01-01

380

Sandpile formation by revolving rivers  

E-print Network

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.

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

2002-06-25

381

Selective formation of tungsten nanowires  

PubMed Central

We report on a process for fabricating self-aligned tungsten (W) nanowires with polycrystalline silicon core. Tungsten nanowires as thin as 10 nm were formed by utilizing polysilicon sidewall transfer technology followed by selective deposition of tungsten by chemical vapor deposition (CVD) using WF6 as the precursor. With selective CVD, the process is self-limiting whereby the tungsten formation is confined to the polysilicon regions; hence, the nanowires are formed without the need for lithography or for additional processing. The fabricated tungsten nanowires were observed to be perfectly aligned, showing 100% selectivity to polysilicon and can be made to be electrically isolated from one another. The electrical conductivity of the nanowires was characterized to determine the effect of its physical dimensions. The conductivity for the tungsten nanowires were found to be 40% higher when compared to doped polysilicon nanowires of similar dimensions. PMID:21970543

2011-01-01

382

Macromolecules Relevant to Stone Formation  

NASA Astrophysics Data System (ADS)

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.

Ryall, Rosemary L.; Cook, Alison F.; Thurgood, Lauren A.; Grover, Phulwinder K.

2007-04-01

383

Polar Cap Formation on Ganymede  

NASA Technical Reports Server (NTRS)

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.

Pilcher, C. B.; Shaya, E. J.

1985-01-01

384

Pattern formation in colloidal explosions  

E-print Network

We study the non-equilibrium pattern formation that emerges when magnetically repelling colloids, trapped by optical tweezers, are abruptly released, forming colloidal explosions. For multiple colloids in a single trap we observe a pattern of expanding concentric rings. For colloids individually trapped in a line, we observe explosions with a zigzag pattern that persists even when magnetic interactions are much weaker than those that break the linear symmetry in equilibrium. Theory and computer simulations quantitatively describe these phenomena both in and out of equilibrium. An analysis of the mode spectrum allows us to accurately quantify the non-harmonic nature of the optical traps. Colloidal explosions provide a new way to generate well-characterized non-equilibrium behaviour in colloidal systems.

Arthur V. Straube; Ard A. Louis; Jörg Baumgartl; Clemens Bechinger; Roel P. A. Dullens

2010-09-10

385

Electrochemical formation of field emitters  

DOEpatents

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.

Bernhardt, A.F.

1999-03-16

386

Defect pressure, formation volume, and temperature dependence of formation properties of point defects in ionic solids  

E-print Network

of the temperature dependence of the shear moduli. The high-temperature anomalies of defect formation volume, tracer at high temperatures [21, 22], assuming that the Schottky defect formation parameters determined to withinDefect pressure, formation volume, and temperature dependence of formation properties of point

Boyer, Edmond

387

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)

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.

Moss, C.

1990-01-01

388

Engram formation in psychiatric disorders.  

PubMed

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

Gebicke-Haerter, Peter J

2014-01-01

389

Cataract formation following vitreoretinal procedures  

PubMed Central

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.

Feng, Hao; Adelman, Ron A

2014-01-01

390

Biomineralization: mineral formation by organisms  

NASA Astrophysics Data System (ADS)

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.

Addadi, Lia; Weiner, Steve

2014-09-01

391

World Ocean Database 2009 (WOD09) Data DVD. The following information describes the structure and contents of the WOD09 DVDs.  

E-print Network

and contents of the WOD09 DVDs. CODES - contains code tables necessary to use WOD09 data. DATA - all data are gzip compressed and stored in WOD native ASCII format. The WOD09 resides on two DVDs. Disk one contains

392

SSE Global Data  

SSE Global Data Text files of monthly averaged data for the entire globe. Some annual averages or annual sums are included. ... 1993 File FormatASCII Order Data:  SSE Global Data: Order Data SCAR-B Block:  ...

2014-09-26

393

SSE Interannual Variability Data  

SSE Interannual Variability Data Monthly and annual averages by year and for a series of ... 1993 File FormatASCII Order Data:  SSE Interannual Variability Data: Order Data FAQ:  SSE: Data Access Questions ...

2014-09-26

394

36 CFR 1235.50 - What specifications and standards for transfer apply to electronic records?  

Code of Federal Regulations, 2011 CFR

...international standards organization. Acceptable transfer formats include the Geography Markup Language (GML) as defined by the Open GIS Consortium. (d) Textual documents . Electronic textual documents must be transferred as plain ASCII files;...

2011-07-01

395

36 CFR 1235.50 - What specifications and standards for transfer apply to electronic records?  

Code of Federal Regulations, 2010 CFR

...international standards organization. Acceptable transfer formats include the Geography Markup Language (GML) as defined by the Open GIS Consortium. (d) Textual documents . Electronic textual documents must be transferred as plain ASCII files;...

2010-07-01

396

Navigate MathSciNet Jump to Search or Browse Screens  

E-print Network

-Support Help Index Select alternative format: BibTeX ASCII MR1962152 (2003m:55003) Colman, Hellen [Colman Vale, Hellen] (1-ILCC); Hurder, Steven (1-ILCC) Tangential LS category and cohomology for foliations. (English

Hurder, Steven

397

37 CFR 270.2 - Reports of use of sound recordings under statutory license for preexisting subscription services.  

Code of Federal Regulations, 2012 CFR

...Format. Reports of Use should be provided on a standard machine-readable medium, such as diskette, optical disc, or magneto-optical disc, and should conform as closely as possible to the following specifications: (1) ASCII...

2012-07-01

398

37 CFR 370.3 - Reports of use of sound recordings under statutory license for preexisting subscription services.  

Code of Federal Regulations, 2012 CFR

...Format. Reports of Use should be provided on a standard machine-readable medium, such as diskette, optical disc, or magneto-optical disc, and should conform as closely as possible to the following specifications: (1) ASCII...

2012-07-01

399

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

NSDL National Science Digital Library

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.)

1996-01-01

400

14 CFR Sec. 19-7 - Passenger origin-destination survey.  

Code of Federal Regulations, 2010 CFR

...or tab delimited ASCII format). X. Glossary of Terms Selected terms used in the foregoing instructions are here defined...abbreviation for automated data processing, which is the term applied to all forms of machine processed data....

2010-01-01

401

Fibril formation from pea protein and subsequent gel formation.  

PubMed

The objective of this study was to characterize fibrillar aggregates made using pea proteins, to assemble formed fibrils into protein-based gels, and to study the rheological behavior of these gels. Micrometer-long fibrillar aggregates were observed after pea protein solutions had been heated for 20 h at pH 2.0. Following heating of pea proteins, it was observed that all of the proteins were hydrolyzed into peptides and that 50% of these peptides were assembled into fibrils. Changes on a structural level in pea proteins were studied using circular dichroism, transmission electron microscopy, and particle size analysis. During the fibril assembly process, an increase in aggregate size was observed, which coincided with an increase in thioflavin T binding, indicating the presence of ?-sheet aggregates. Fibrils made using pea proteins were more branched and curly. Gel formation of preformed fibrils was induced by slow acidification from pH 7.0 to a final pH of around pH 5.0. The ability of pea protein-based fibrillar gels to fracture during an amplitude sweep was comparable to those of soy protein and whey protein-based fibrillar gels, although gels prepared from fibrils made using pea protein and soy protein were weaker than those of whey protein. The findings show that fibrils can be prepared from pea protein, which can be incorporated into protein-based fibrillar gels. PMID:24564788

Munialo, Claire Darizu; Martin, Anneke H; van der Linden, Erik; de Jongh, Harmen H J

2014-03-19

402

Formation temperatures of thermogenic and biogenic methane  

USGS Publications Warehouse

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.

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.

2014-01-01

403

Formation of the solar system  

NSDL National Science Digital Library

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.

Urbano, Lensyl

404

A model for fingerprint formation  

NASA Astrophysics Data System (ADS)

The uniqueness of fingerprints (epidermal ridges) has been recognized for over two thousand years. They have been studied scientifically for more than two hundred years. Yet, in spite of the accumulation of a wealth of empirical and experimental knowledge, no widely accepted explanation for the development of epidermal ridges on fingers, palms and soles has yet emerged. Informed by an extensive literature study we suggest that fingerprint patterns are created as the result of a buckling instability in the basal cell layer of the fetal epidermis. Analysis of the well-known von Karman equations informs us that the buckling direction is perpendicular to the direction of greatest stress in the basal layer. We propose that this stress is induced by resistance of furrows and creases to the differential growth of the basal layer and regression of the volar pads during the time of ridge formation. These theories have been tested by computer experiments. The results are in close harmony with observations. Specifically, they are consistent with the well-known observation that the pattern type depends on the geometry of the fingertip surface when fingerprint patterns are formed.

Kücken, M.; Newell, A. C.

2004-10-01

405

Stages of neuronal network formation  

NASA Astrophysics Data System (ADS)

Graph theoretical approaches have become a powerful tool for investigating the architecture and dynamics of complex networks. The topology of network graphs revealed small-world properties for very different real systems among these neuronal networks. In this study, we observed the early development of mouse retinal ganglion cell (RGC) networks in vitro using time-lapse video microscopy. By means of a time-resolved graph theoretical analysis of the connectivity, shortest path length and the edge length, we were able to discover the different stages during the network formation. Starting from single cells, at the first stage neurons connected to each other ending up in a network with maximum complexity. In the further course, we observed a simplification of the network which manifested in a change of relevant network parameters such as the minimization of the path length. Moreover, we found that RGC networks self-organized as small-world networks at both stages; however, the optimization occurred only in the second stage.

Woiterski, Lydia; Claudepierre, Thomas; Luxenhofer, Robert; Jordan, Rainer; Käs, Josef A.

2013-02-01

406

Cosmic vacuum and galaxy formation  

NASA Astrophysics Data System (ADS)

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.

Chernin, A. D.

2006-04-01

407

Laminin receptors for neurite formation.  

PubMed Central

Laminin, a basement membrane glycoprotein promotes both cell attachment and neurite outgrowth. Separate domains on laminin elicit these responses, suggesting that distinct receptors occur on the surface of cells. NG108-15 neuroblastoma-glioma cells rapidly extend long processes in the presence of laminin. We report here that 125I-labeled laminin specifically binds to these cells and to three membrane proteins of 67, 110, and 180 kDa. These proteins were isolated by affinity chromatography on laminin-Sepharose. The 67-kDa protein reacted with antibody to the previously characterized receptor for cell attachment to laminin. Antibodies to the 110-kDa and 180-kDa bands demonstrated that the 110-kDa protein was found in a variety of epithelial cell lines and in brain, whereas the 180-kDa protein was neural specific. Antibodies prepared against the 110-kDa and 180-kDa proteins inhibited neurite outgrowth induced by the neurite-promoting domain of laminin, whereas antibodies to the 67-kDa laminin receptor had no effect on neurite outgrowth. We conclude that neuronal cells have multiple cell-surface laminin receptors and that the 110-kDa and 180-kDa proteins are involved in neurite formation. Images PMID:2963341

Kleinman, H K; Ogle, R C; Cannon, F B; Little, C D; Sweeney, T M; Luckenbill-Edds, L

1988-01-01

408

Star Formation in Tadpole Galaxies  

E-print Network

Tadpole Galaxies look like a star forming head with a tail structure to the side. They are also named cometaries. In a series of recent works we have discovered a number of issues that lead us to consider them extremely interesting targets. First, from images, they are disks with a lopsided starburst. This result is firmly established with long slit spectroscopy in a nearby representative sample. They rotate with the head following the rotation pattern but displaced from the rotation center. Moreover, in a search for extremely metal poor (XMP) galaxies, we identified tadpoles as the dominant shapes in the sample- nearly 80% of the local XMP galaxies have a tadpole morphology. In addition, the spatially resolved analysis of the metallicity shows the remarkable result that there is a metallicity drop right at the position of the head. This is contrary to what intuition would say and difficult to explain if star formation has happened from gas processed in the disk. The result could however be understood if the ...

Munoz-Tunon, Casiana; Elmegreen, Debra M; Elmegreen, Bruce G

2014-01-01

409

Spheromak formation studies in SSPX  

SciTech Connect

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.

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

410

Student use of formative assessments and progress charts of formative assessments in the 7th grade science class.  

E-print Network

??In this investigation formative assessments and a progress chart of formative assessments were implemented with the purpose of improving student engagement and learning. Formative assessments… (more)

McKenna, Emily Sue.

2011-01-01

411

Towards the Rosetta Stone of planet formation  

Microsoft Academic Search

Transiting exoplanets (TEPs) observed just about 10 Myrs after formation of\\u000atheir host systems may serve as the Rosetta Stone for planet formation\\u000atheories. They would give strong constraints on several aspects of planet\\u000aformation, e.g. time-scales (planet formation would then be possible within 10\\u000aMyrs), the radius of the planet could indicate whether planets form by\\u000agravitational collapse (being

G. Maciejewski; R. Neuhaeuser; R. Errmann; M. Mugrauer; Ch. Adam; A. Berndt; T. Eisenbeiss; S. Fiedler; Ch. Ginski; M. Hohle; U. Kramm; C. Marka; M. Moualla; T. Pribulla; St. Raetz; T. Roell; T. O. B. Schmidt; M. Seeliger; I. Spaleniak; N. Tetzlaff; L. Trepl

2010-01-01

412

Massive Star and Star Cluster Formation  

E-print Network

I review the status of massive star formation theories: accretion from collapsing, massive, turbulent cores; competitive accretion; and stellar collisions. I conclude the observational and theoretical evidence favors the first of these models. I then discuss: the initial conditions of star cluster formation as traced by infrared dark clouds; the cluster formation timescale; and comparison of the initial cluster mass function in different galactic environments.

Jonathan C. Tan

2006-10-16

413

Star Formation in Cluster Cooling Flows  

E-print Network

New X-ray observations from the {\\it Chandra} and XMM-{\\it Newton} observatories have shown that cooling of the intracluster medium is occurring at rates that are now approaching the star formation rates measured in cD galaxies at the bases of cooling flows. Star formation proceeds in repeated episodes, possibly indicating an intermittent fuel supply. Coupled with new evidence for heating by AGN, a new paradigm of self-regulated cooling and star formation in cluster cores is emerging.

B. R. McNamara

2004-02-03

414

Distributed Simulation for Formation Flying Applications  

Microsoft Academic Search

High delit y engineering simulation plays a key role in the rapidly developing eld of space-based formation ying. This paper describes the design and implementation of the Formation Algorithms and Simulation Testbed (FAST).1 This testbed was designed to provide real-time, high-delit y engineering simulation of multiple spacecraft operating in formation. By distributing the simulation across multiple CPUs, the FAST provides

Garett A. Sohl; Santi Udomkesmalee; Jennifer L. Kellogg

415

Processes and problems in secondary star formation  

SciTech Connect

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.

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

1984-03-01

416

Heating tar sands formations to visbreaking temperatures  

DOEpatents

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.

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

417

Dominant diffusing species during cobalt silicide formation  

NASA Astrophysics Data System (ADS)

The dominant moving species during cobalt monosilicide and cobalt disilicide formation has been examined using a thin tantalum layer as a metal marker. The marker data obtained following the formation of CoSi from Co2Si showed that monosilicide growth was essentially due Si diffusion only. When used to study CoSi2 formation, the data indicated that silicon was also the dominant moving species during disilicide formation, although a noninsignificant amount of cobalt diffusion was also observed to take place.

Comrie, C. M.; Newman, R. T.

1996-01-01

418

Bursal synovial chondromatosis formation following osteochondroma resection.  

PubMed

Osteochondroma is a common tumor of the bone and can be complicated by adventitial bursa formation and malignant transformation of the cartilaginous cap. Synovial chondromatosis formation within these bursae is extremely rare and can be confused with malignant transformation of the osteochondroma cap to a chondrosarcoma. We describe a case of extra-articular synovial chondromatosis formation several years following osteochondroma resection. Cartilage nodule formation within the bursal synovial lining and proliferation of cartilage debris shed from the cartilaginous cap during surgery or biopsy are potential etiologies of this rare complication of osteochondromas. PMID:24453028

Lin, Yu-Ching; Goldsmith, Jeffrey D; Gebhardt, Mark G; Wu, Jim S

2014-07-01

419

On instruction sets and their formats  

NASA Technical Reports Server (NTRS)

Central to instruction set design is the issue of the instruction format. Some common format encoding techniques are discussed, and a method of representing high-level language parse trees by means of formats that cover successively larger portions of a tree is introduced. Variations are introduced on the method that represent directed acyclic graphs as well as simple parse trees, and that encode constants in a special fashion. For a particular representation, the number of times each format is executed to run a sample program to completion is measured.

Flynn, M. J.; Johnson, J. D.; Wakefield, S. P.

1985-01-01

420

Star formation region in Vela  

NASA Astrophysics Data System (ADS)

A star formation region connected with SNO 41 is investigated. The observations of this region were carried out in the 12CO (1-0) line and in the 1.2-mm (with SIMBA) with the 15-m SEST mm telescope (Cerro La Silla, Chile). A blue shifted outflow is revealed from the 12CO(1-0) observations, while a bipolar outflow is apparent from the 1.2-mm SIMBA image. In CO it seems that a very faint dust envelope around SNO 41 probably exists, which is expanding with a velocity of ˜10.5 km/s. The distance to SNO 41 is estimated as ˜1500 pc. There are outflows also present in 2MASS images. A spiral jet has a condensation (resembling a HH object) at the end. Another jet has a discontinuity and a bow-shock-like structure on it. In 2MASS images there are also spots resembling HH objects. In this region there is also a rather luminous point source (IRAS 08546-4254), which has IR colors typical for an YSO connected with a water maser. The detection of a strong CS (2-1) line emission toward IRAS 08546-4254, with the same velocity as the CO line, shows the existence of a high density core of molecular gas associated to this source. A methanol maser is also associated with that IRAS source. The existence of CS line emission and a methanol maser (at 6.669 Ghz) is an indication of the presence of a very young massive star. It is not excluded that this IRAS source is the center of outflows mentioned above, because this source coincides with the center of the 1.2-mm SIMBA image and also with the place of origin of the jet with bow-shock-like structure.

Gyulbudaghian, A. L.; May, J.

2007-01-01

421

Formation of the giant planets  

NASA Technical Reports Server (NTRS)

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.

Lissauer, Jack J.

2006-01-01

422

Thermodynamics of ?-amyloid fibril formation  

NASA Astrophysics Data System (ADS)

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.

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

2004-05-01

423

Pore formation by Cry toxins.  

PubMed

Bacillus thuringiensis (Bt) bacteria produce insecticidal Cry and Cyt proteins used in the biological control of different insect pests. In this review, we will focus on the 3d-Cry toxins that represent the biggest group of Cry proteins and also on Cyt toxins. The 3d-Cry toxins are pore-forming toxins that induce cell death by forming ionic pores into the membrane of the midgut epithelial cells in their target insect. The initial steps in the mode of action include ingestion of the protoxin, activation by midgut proteases to produce the toxin fragment and the interaction with the primary cadherin receptor. The interaction of the monomeric CrylA toxin with the cadherin receptor promotes an extra proteolytic cleavage, where helix alpha-1 of domain I is eliminated and the toxin oligomerization is induced, forming a structure of 250 kDa. The oligomeric structure binds to a secondary receptor, aminopeptidase N or alkaline phosphatase. The secondary receptor drives the toxin into detergent resistant membrane microdomains formingpores that cause osmotic shock, burst of the midgut cells and insect death. Regarding to Cyt toxins, these proteins have a synergistic effect on the toxicity of some Cry toxins. Cyt proteins are also proteolytic activated in the midgut lumen of their target, they bind to some phospholipids present in the mosquito midgut cells. The proposed mechanism of synergism between Cry and Cyt toxins is that Cyt1Aa function as a receptor for Cry toxins. The Cyt1A inserts into midgut epithelium membrane and exposes protein regions that are recognized by Cry11Aa. It was demonstrated that this interaction facilitates the oligomerization of Cry11Aa and also its pore formation activity. PMID:20687486

Soberón, Mario; Pardo, Liliana; Muñóz-Garay, Carlos; Sánchez, Jorge; Gómez, Isabel; Porta, Helena; Bravo, Alejandra

2010-01-01

424

STAR FORMATION IN 30 DORADUS  

SciTech Connect

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.

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

425

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

E-print Network

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 ...

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

2005-02-01

426

Effect of lead on dental enamel formation  

Microsoft Academic Search

In this work the effects of lead toxicity on dental enamel formation were studied. Epidemiological data and animal studies show an association between lead exposure and higher caries prevalence, but the mechanism underlying this association is still unknown. Here we present data on enamel formation in rats exposed to lead for 70 days in the drinking water. Enamel matrix was

Raquel F. Gerlach; Jaime A. Cury; Francisco J. Krug; Sérgio R. P. Line

2002-01-01

427

Molecular mechanisms of vascular pattern formation  

Microsoft Academic Search

Vascular plants have developed a complex network of vascular systems through the plant body, allowing efficient transport of water, nutrients and signals. To understand molecular mechanisms of vascular pattern formation, we have made two approaches. First we have isolated Arabidopsis mutants with defects in vascular pattern formation. Microscopic and genetic examination of the cotyledonary venation of 3400 M3 lines led

Hiroo Fukuda; Koji Koizumi; Kenji Motomatsu; Hiroyasu Motose; Munetaka Sugiyama

2001-01-01

428

DISSERTATION FORMATION OF THE HURRICANE EYE  

E-print Network

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

Schubert, Wayne H.

429

Star formation history in distant radio galaxies  

Microsoft Academic Search

Past star formation in distant radio galaxies can be analyzed from blue to infrared energy distributions while ongoing activity can be traced by ultra-violet to blue distributions and emission lines. Typical signatures of evolved population are red continua, stellar lines, and the 4000Å break. Old ages and an intense past activity are determined for most galaxies even if star formation

Brigitte Rocca-Volmerange

1999-01-01

430

The Political Dilemmas of Formative Assessment  

ERIC Educational Resources Information Center

The literature base on using formative assessment for instructional and intervention decisions is formidable, but the history of the practice of formative assessment is spotty. Even with the pressures of high-stakes accountability, its definition is fuzzy, its adoption is inconsistent, and the prognosis for future use is questionable. A historical…

Dorn, Sherman

2010-01-01

431

Coal Combustion Aerosol Formation Mechanisms: A Review  

Microsoft Academic Search

The composition and size distribution of particles emitted by coal combustion sources depend upon various mechanisms leading to their formation. A review of current ideas about possible mechanisms for formation of combustion aerosols is presented. Available data regarding fly ash size distribution and elemental concentrations in various size fractions were analyzed. These data were qualitatively compared with theoretical model predictions

A. S. Damle; D. S. Ensor; M. B. Ranade

1981-01-01

432

Star Formation in the Intergalactic Medium  

Microsoft Academic Search

Recent observations have shown that star formation may occur in the intergalactic medium outside any pre-existing stellar structure. Many of such giant HII complexes are progenitors of super star clusters or -- if they are very luminous -- dwarf galaxies, and are associated with tidal debris found in the vicinity of interacting systems. How star formation proceeds in this particular,

Ute Lisenfeld

2004-01-01

433

The New Galaxy: Signatures of Its Formation  

Microsoft Academic Search

The formation and evolution of galaxies is one of the great outstanding problems of astrophysics. Within the broad context of hierachical structure formation, we have only a crude picture of how galaxies like our own came into existence. A detailed physical picture where individual stellar populations can be associated with (tagged to) elements of the protocloud is far beyond our

Ken Freeman; Joss Bland-Hawthorn

2002-01-01

434

Harnessing Collaborative Annotations on Online Formative Assessments  

ERIC Educational Resources Information Center

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…

Lin, Jian-Wei; Lai, Yuan-Cheng

2013-01-01

435

[Reducing bromate formation by catalyzed ozonation].  

PubMed

The yield of bromate formed in catalytic ozonation in the presence of metal oxides was studied with bromide bearing water. The effects of catalyst dose, bromide concentration, pH, and temperature on the formation of bromate during catalytic ozonation were also discussed. Lab scale experiments showed that catalytic ozonation could decrease 85.1% bromate formation by increasing cerium oxide dosage from 0 to 250 mg/L. Catalytic ozonation can decrease 69.2% , 83.5% and 15.2% bromate formation when bromide concentrations are 0.5, 1.0 and 2.0 mg/L respectively. The effect of bromide concentration on the reduction of bromate in the catalytic ozonation was not clear. The increase of pH showed negative effect on reducing bromate formation in the catalytic ozonation. Catalytic ozonation can decrease 43%-59% of bromate formation with the temperature in the range of 5-25 degrees C (bromide concentration was 1.5 mg/L). The variation of temperature in water had not significant influence on the inhibition of bromate formation in catalytic ozonation. The low bromate formation in catalytic ozonation was due to the inhibition of the reaction between molecular ozone and hypobromite by the catalyst. Since the inhibition of bromate formation in catalytic ozonation was weakened by the presence of sulfate, the function of the catalyst should be related to surface sites of the catalyst. PMID:18441924

He, Ru; Lu, Jin-Feng; Ma, Jun; Zhang, Tao; Chen, Wei-Peng

2008-01-01

436

Endocannabinoid Signaling is Critical for Habit Formation  

PubMed Central

Extended training can induce a shift in behavioral control from goal-directed actions, which are governed by action-outcome contingencies and sensitive to changes in the expected value of the outcome, to habits which are less dependent on action-outcome relations and insensitive to changes in outcome value. Previous studies in rats have shown that interval schedules of reinforcement favor habit formation while ratio schedules favor goal-directed behavior. However, the molecular mechanisms underlying habit formation are not well understood. Endocannabinoids, which can function as retrograde messengers acting through presynaptic CB1 receptors, are highly expressed in the dorsolateral striatum, a key region involved in habit formation. Using a reversible devaluation paradigm, we confirmed that in mice random interval schedules also favor habit formation compared with random ratio schedules. We also found that training with interval schedules resulted in a preference for exploration of a novel lever, whereas training with ratio schedules resulted in less generalization and more exploitation of the reinforced lever. Furthermore, mice carrying either a heterozygous or a homozygous null mutation of the cannabinoid receptor type I (CB1) showed reduced habit formation and enhanced exploitation. The impaired habit formation in CB1 mutant mice cannot be attributed to chronic developmental or behavioral abnormalities because pharmacological blockade of CB1 receptors specifically during training also impairs habit formation. Taken together our data suggest that endocannabinoid signaling is critical for habit formation. PMID:18958234

Hilario, Monica R.F.; Clouse, Emily; Yin, Henry H.; Costa, Rui M.

2007-01-01

437

Evolutionary consequences of dating the Yixian Formation  

Microsoft Academic Search

The Yixian Formation of northeastern China has yielded important new fossils that are fuelling debates on the origin of angiosperms, on the early radiation of birds and of mammals, and on the origin of feathers. Although these fossils provide a wealth of detailed anatomical information, knowledge of the absolute age of the Yixian Formation is crucial if we are to

Paul M. Barrett

2000-01-01

438

XML Format for SESAME and LEOS  

Microsoft Academic Search

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

J K Durrenberger; J R Neely; P A Sterne

2009-01-01

439

Early Formative Evaluation of Educational Television  

Microsoft Academic Search

This article examines the incorporation of formative evaluation in the early stages of ETV programme development, and argues that Self?Formative Evaluation, an evaluation system conducted by the developers of an ETV programme and in?house evaluators, should be conducted. A list of criteria that can be used in this evaluation process is given

A. Duby

1988-01-01

440

Controlling Formations of Multiple Mobile Robots  

Microsoft Academic Search

We investigate feedback laws used to control multiple robots moving together in a formation. We propose a method for controlling formations that uses only local sensor-based information, in a leader-follower motion. We use methods of feedback linearization to exponentially stabilize the relative distance and orientation of the follower, and show that the zero dynamics of the system are also (asymptotically)

Jaydev P. Desai; James P. Ostrowski; Vijay Kumar

1998-01-01

441

Inhibition of Staphylococcal Biofilm Formation by Nitrite  

Microsoft Academic Search

Several environmental stresses have been demonstrated to increase polysaccharide intercellular adhesin (PIA) synthesis and biofilm formation by the human pathogens Staphylococcus aureus and Staphylococcus epidermidis. In this study we characterized an adaptive response of S. aureus SA113 to nitrite-induced stress and show that it involves concomitant impairment of PIA synthesis and biofilm formation. Transcriptional analysis provided evidence that nitrite, either

Steffen Schlag; Christiane Nerz; Timo A. Birkenstock; Florian Altenberend; Friedrich Gotz

2007-01-01

442

Formation, frequency and spacing of habitable planets  

Microsoft Academic Search

Models of planet formation and of the orbital stability of planetary systems are described and used to discuss estimates of the abundance of habitable planets which may orbit stars within our galaxy. Theories of star and planet formation, which are based on observations of the solar system and of young stars and their environments, predict that most single stars should

Jack J. Lissauer

1997-01-01

443

43 CFR 10010.26 - Format.  

Code of Federal Regulations, 2013 CFR

...Proposed departures from the standard format described in the CEQ regulations and this part must be approved by the Executive Director...information is not discussed elsewhere in the document. (d) If CEQ's standard format is not used or if the EIS is combined...

2013-10-01

444

43 CFR 10010.26 - Format.  

Code of Federal Regulations, 2012 CFR

...Proposed departures from the standard format described in the CEQ regulations and this part must be approved by the Executive Director...information is not discussed elsewhere in the document. (d) If CEQ's standard format is not used or if the EIS is combined...

2012-10-01

445

Implementation of Formative Assessment in the Classroom  

ERIC Educational Resources Information Center

This report details the work defined by a doctoral team looking at the literacy and implementation of formative assessment in classrooms in Southwest Missouri. The mission of this project was to identify the formative assessment literacy levels and the degree of classroom implementation of these strategies in districts and the resulting…

Edman, Elaina; Gilbreth, Stephen G.; Wynn, Sheila

2010-01-01

446

Composition for selectively reducing subterranean formation permeability  

Microsoft Academic Search

This patent describes a process for selectively reducing the water permeability of a hydrocarbon-containing subterranean formation. It comprises contacting an inorganic crosslinking agent with an aqueous solution comprising at least some cationic polyacrylamide to form a composition; injecting the composition into at least a portion of the subterranean formation, wherein the composition forms a visible gel in at least a

R. D. Hutchins; H. T. Dovan

1992-01-01

447

Lipase catalyzed formation of flavour esters  

Microsoft Academic Search

Summary Thirteen commercial lipase preparations were checked for their ability to catalyse the formation of flavour esters (isoamyl or geranyl acetate, propionate and butyrate) by either direct esterification or ester solvolysis in n-heptane. The formation of isoamyl or geranyl butyrates and propionates by direct esterification was catalyzed by the majority of the tested lipases. Acetic acid esters were more difficult

G. Langrand; C. Triantaphylides; J. Baratti

1988-01-01

448

APPREND: Formative Assessment Tools for APP  

ERIC Educational Resources Information Center

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.)

Sherborne, Tony

2009-01-01

449

Formative Assessments in a Professional Learning Community  

ERIC Educational Resources Information Center

The ideas and examples in this book help teachers successfully collaborate to raise student achievement through the use of formative assessments. Here, Todd Stanley and Betsy Moore, educators with over 40 years of combined experience, offer proven formative assessment strategies to teachers in a professional learning community. Contents include:…

Stanley, Todd; Moore, Betsy

2011-01-01

450

Shell Formation and Bone Strength Laying Hens  

E-print Network

Shell Formation and Bone Strength in Laying Hens Effects of Age, Daidzein and Exogenous Estrogen Cover aquarelle: E. Spörndly-Nees #12;Shell Formation and Bone Strength in Laying Hens Effects of Age as well as an economical problem. Parallel with reduced shell quality the bone strength declines

451

Mechanisms of gas hydrate formation and inhibition  

Microsoft Academic Search

The formation of gas hydrates in gas and oil subsea pipelines often results in blockage and shutdown of these pipelines. Modern control methods depend on understanding the mechanisms through which gas hydrates form. This paper reviews our recent studies of clathrate hydrate formation and inhibition mechanisms using neutron diffraction, differential scanning calorimetry (DSC) and a multiple cell photo-sensing instrument. The

C. A. Koh; R. E. Westacott; W. Zhang; K. Hirachand; J. L. Creek; A. K. Soper

2002-01-01

452

Formative Assessment in the High School IMC  

ERIC Educational Resources Information Center

In this article, the author discusses how she uses formative assessments of information literacy skills in the high school IMC. As a result of informal observation and conversations with individual students--a form of formative assessment itself--the author learned that students were not using indexes to locate relevant information in nonfiction…

Edwards, Valerie A.

2007-01-01

453

Image formation with a concave spherical mirror  

Microsoft Academic Search

The author presents an elementary theory of image formation by a concave spherical mirror, elaborated for arbitrary angles of incidence and wide beams of rays. The image formation of a point source is either real, virtual or mixed according to the position of the source with respect to the mirror. If the ratio of the diameter of the mirror to

B. Jurek

1967-01-01

454

Distributed Diagnosis in Formations of Mobile Robots  

E-print Network

1 Distributed Diagnosis in Formations of Mobile Robots Matthew J. Daigle, Xenofon D. Koutsoukos can degrade or develop faults during operation, and, therefore, require online diagnosis algorithms diagnosis approach for formations of mobile robots. The approach is based on a bond graph modeling framework

Daigle, Matthew

455

ECCM98 Publication Format Richard M Young  

E-print Network

ECCM­98 Publication Format Richard M Young Department of Psychology University of Hertfordshire In this paper, we describe the formatting requirements for ECCM­98, the second European Conference on Cognitive Modelling, and we offer a number of suggestions on writing style for the international ECCM readership

Young, Richard M.

456

A Critical Test of Structure Formation Models  

Microsoft Academic Search

We seek to constrain current models of structure formation and the hypothesis of maximal disks in luminous spiral galaxies. Structure formation models based on most CDM cosmologies favor dark galactic halos that dominate the potential even in the inner parts of galaxies. Opposite conclusions are reached if the rotation curve of galaxies can only be modeled with the highest (maximal)

Stephane Courteau; Matthew Bershady; Hans-Walter Rix; David Andersen

2002-01-01

457

A UNIMARC Bibliographic Format Database for ABCD  

ERIC Educational Resources Information Center

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.…

Megnigbeto, Eustache

2012-01-01

458

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

E-print Network

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^+\

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

2009-12-01

459

Historical Perspective on Computational Star Formation  

E-print Network

This contribution presents the introductory historical remarks that I made at IAU Symposium 270 on Computational Star Formation in Barcelona, May 31 - June 4, 2010. I give a personal view of some of the early histoy of the subject, and I comment on what I think were some of the most important things learned from numerical work on star formation.

Larson, Richard B

2010-01-01

460

First Structure Formation and the First Stars  

E-print Network

We discuss the results of recent 3D simulations of first structure formation in relationship to the formation of the first stars. On the basis of a new, high-resolution AMR simulation (spatial dynamic range = 30,000,000), we conclude that the first stars are likely to be massive.

Michael L. Norman; Tom Abel; Greg Bryan

2000-05-11

461

Arabic Formatting with DITROFF\\/FFORTID  

Microsoft Academic Search

SUMMARY This paper describes an Arabic formatting system that is able to format multilingual scientific documents, containing text in Arabic or Persian, as well as other languages, plus pictures, graphs, formulae, tables, bibliographical citations, and bibliographies. The system is an extension of ditroff\\/ffortid that is already capable of handling Hebrew in the context of multi- lingual scientific documents. ditroff\\/ffortid itself

Johny Srouji; Daniel M. Berry

1992-01-01

462

Early Formation of Terrestrial Crust  

NASA Astrophysics Data System (ADS)

Early (?4.5 Ga) Formation of Terrestrial Crust T.M. Harrison1, A.K. Schmitt1, M.T. McCulloch2, and O.M. Lovera1 1Department of Earth and Space Sciences and IGPP, UCLA, Los Angeles, CA 90095, USA; 2Research School of Earth Sciences, Australian National University, Canberra, A.C.T. 2601 AUSTRALIA Large deviations in ?repsilonHf(T) from bulk silicate Earth seen in >4 Ga detrital zircons from Jack Hills, Western Australia, have been interpreted as reflecting a major differentiation of the silicate Earth at ca. 4.4 to 4.5 Ga. We have expanded the characterization of 176Hf/177Hf (Hf) in Hadean zircons by acquiring a further 116 laser ablation Lu-Hf measurements on 87 grains with ion microprobe 207Pb/206Pb ages up to 4.36 Ga. Most measurements employed concurrent Lu-Hf and 207Pb/206Pb analyses, permitting assessment of the use of ion microprobe data to characterize the age of the volumetrically larger domain sampled by laser drilling. Our new results confirm and extend the earlier observation of significant negative deviations in ?repsilonHf(T) throughout the Hadean, although no positive ?repsilonHf(T) values were documented in this study. These data yields an essentially uniform spectrum of single-stage model ages between 4.54 and 4.20 Ga for extraction of the zircons' protoliths from a chondritic reservoir. We derived the full error propagation expression for a parameter, ?repsilono, which measures the difference of a sample from solar system initial (Hf) (Hfo), and from this conclude that data plotting close to (Hfo), are statistically meaningful and consistent with silicate differentiation at 4.540±0.006 Ga. ?18O and Ti thermometry for these Hadean zircons show little obvious correlation with initial (Hf), consistent with their derivation through fusion of a broad suite of crustal rock types under near water-saturated conditions. Together with the inclusion assemblage and other isotopic and trace element data obtained from these ancient zircons, our results indicate essentially continuous derivation of crust from the mantle from 4.5 to 4.2 Ga, concurrent with recycling into the mantle and internal crustal re-working. These results represent further evidence that by 4.35 Ga, portions of the crust had taken on continental characteristics.

Harrison, T. M.; Schmitt, A. K.; McCulloch, M. T.; Lovera, O. M.

2007-12-01

463

Formation of parting in quartz  

NASA Astrophysics Data System (ADS)

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.

Jørgen Kjøll, Hans; Eske Sørensen, Bjørn

2014-05-01

464

Optimal Configurations for Rotating Spacecraft Formations  

NASA Technical Reports Server (NTRS)

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.

Hughes, Steven P.; Hall, Christopher D.

2000-01-01

465

Origin and formation of planetary systems.  

PubMed

To estimate the occurrence of terrestrial exoplanets and maximize the chance of finding them, it is crucial to understand the formation of planetary systems in general and that of terrestrial planets in particular. We show that a reliable formation theory should not only explain the formation of the Solar System, with small terrestrial planets within a few AU and gas giants farther out, but also the newly discovered exoplanetary systems with close-in giant planets. Regarding the presently known exoplanets, we stress that our current knowledge is strongly biased by the sensitivity limits of current detection techniques (mainly the radial velocity method). With time and improved detection methods, the diversity of planets and orbits in exoplanetary systems will definitely increase and help to constrain the formation theory further. In this work, we review the latest state of planetary formation in relation to the origin and evolution of habitable terrestrial planets. PMID:20307180

Alibert, Y; Broeg, C; Benz, W; Wuchterl, G; Grasset, O; Sotin, C; Eiroa, Carlos; Henning, Thomas; Herbst, Tom; Kaltenegger, Lisa; Léger, Alain; Liseau, Réne; Lammer, Helmut; Beichman, Charles; Danchi, William; Fridlund, Malcolm; Lunine, Jonathan; Paresce, Francesco; Penny, Alan; Quirrenbach, Andreas; Röttgering, Huub; Selsis, Frank; Schneider, Jean; Stam, Daphne; Tinetti, Giovanna; White, Glenn J

2010-01-01

466

Star Formation in Transient Molecular Clouds  

E-print Network

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.

Paul C. Clark; Ian A. Bonnell

2003-11-12

467

Formation Flying Control of Multiple Spacecraft  

NASA Technical Reports Server (NTRS)

The problem of coordination and control of multiple spacecraft (MS) moving in formation is considered. Here, each MS is modeled by a rigid body with fixed center of mass. First, various schemes for generating the desired formation patterns are discussed, Then, explicit control laws for formation-keeping and relative attitude alignment based on nearest neighbor-tracking are derived. The necessary data which must be communicated between the MS to achieve effective control are examined. The time-domain behavior of the feedback-controlled MS formation for typical low-Earth orbits is studied both analytically and via computer simulation. The paper concludes with a discussion of the implementation of the derived control laws, and the integration of the MS formation coordination and control system with a proposed inter-spacecraft communication/computing network.