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Sample records for adobe acrobat format

  1. Adobe acrobat: an alternative electronic teaching file construction methodology independent of HTML restrictions.

    PubMed

    Katzman, G L

    2001-03-01

    The goal of the project was to create a method by which an in-house digital teaching file could be constructed that was simple, inexpensive, independent of hypertext markup language (HTML) restrictions, and appears identical on multiple platforms. To accomplish this, Microsoft PowerPoint and Adobe Acrobat were used in succession to assemble digital teaching files in the Acrobat portable document file format. They were then verified to appear identically on computers running Windows, Macintosh Operating Systems (OS), and the Silicon Graphics Unix-based OS as either a free-standing file using Acrobat Reader software or from within a browser window using the Acrobat browser plug-in. This latter display method yields a file viewed through a browser window, yet remains independent of underlying HTML restrictions, which may confer an advantage over simple HTML teaching file construction. Thus, a hybrid of HTML-distributed Adobe Acrobat generated WWW documents may be a viable alternative for digital teaching file construction and distribution. PMID:11310916

  2. Project Adobe. Final Report.

    ERIC Educational Resources Information Center

    Van Curen, Sallie A.

    This final report describes activities and accomplishments of Project Adobe, the New Mexico Parent Training and Information Center, which provides information, support, education and training to families with school-aged children with disabilities in their local communities. Achievements include: (1) completion and printing of a booklet on the…

  3. Adobe Boxes: Locating Object Proposals Using Object Adobes.

    PubMed

    Fang, Zhiwen; Cao, Zhiguo; Xiao, Yang; Zhu, Lei; Yuan, Junsong

    2016-09-01

    Despite the previous efforts of object proposals, the detection rates of the existing approaches are still not satisfactory enough. To address this, we propose Adobe Boxes to efficiently locate the potential objects with fewer proposals, in terms of searching the object adobes that are the salient object parts easy to be perceived. Because of the visual difference between the object and its surroundings, an object adobe obtained from the local region has a high probability to be a part of an object, which is capable of depicting the locative information of the proto-object. Our approach comprises of three main procedures. First, the coarse object proposals are acquired by employing randomly sampled windows. Then, based on local-contrast analysis, the object adobes are identified within the enlarged bounding boxes that correspond to the coarse proposals. The final object proposals are obtained by converging the bounding boxes to tightly surround the object adobes. Meanwhile, our object adobes can also refine the detection rate of most state-of-the-art methods as a refinement approach. The extensive experiments on four challenging datasets (PASCAL VOC2007, VOC2010, VOC2012, and ILSVRC2014) demonstrate that the detection rate of our approach generally outperforms the state-of-the-art methods, especially with relatively small number of proposals. The average time consumed on one image is about 48 ms, which nearly meets the real-time requirement. PMID:27305680

  4. Attentional Focus Effects in Balance Acrobats

    ERIC Educational Resources Information Center

    Wulf, Gabriele

    2008-01-01

    Performing and learning motor skills has been shown to be enhanced if the performer adopts an external relative to internal focus (or no focus) of attention (Wulf, 2007). The present study examined the generalizability of this effect to top-level performers (balance acrobats). Participants performed a balance task (standing on an inflated rubber…

  5. General overview of adobe, looking northwest. South wing is at ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    General overview of adobe, looking northwest. South wing is at left, and central courtyard, with ovens, at center. (recreation of HABS No. CA-38-P152-3 - Vallejo Adobe, Adobe Road at Casa Grande, Petaluma, Sonoma County, CA

  6. Preservation of adobe buildings. Study of materials

    NASA Astrophysics Data System (ADS)

    Velosa, A.; Rocha, F.; Costa, C.; Varum, H.

    2012-04-01

    Adobe buildings are common in the central region of Portugal due to the lack of natural stone in the surrounding area. This type of construction technique lasted until the 20th Century, at which time cementitious materials, with faster hardening and greater structural capacity substituted traditional materials and techniques. Currently, a significant percentage of these buildings is vacant and many are degraded and in need of conservation actions. Adobes from central Portugal are distinctive as they are lightly coloured and made from air lime and quarry sand. Although some adobes were manufactured locally, most were produced almost 'industrially' and sold to nearby regions. In order to preserve this heritage, conservation actions must be undertaken. So as to ensure the adequacy of these actions and compatibility between original materials and new ones, a thorough study of adobe compostion is mandatory. The current study is an initial step in the characterization of earth based construction materials from central Portugal. Adobe samples were collected from residential buildings in two different locations. The determination of the composition of adobe blocks encompassed the determination of the binder fraction and of their chemical composition and also the particle size analysis of the aggregate. For this purpose FRX analysis, acid dissolution and dry sieving were performed. Methylene blue test was also executed in order to determine the clay fraction. Additionally, the mineral composition of powder samples and oriented samples was performed using XRD analysis in order to determine the clay minerals present in the blocks. As adobe blocks are extremely prone to the action of water the Geelong test was undertaken in order to provide information in terms of durability. It was concluded that air lime was generally used in adobe compositions. However, the clay content varies in adobes from different regions, providing distinct durability characteristics to these materials.

  7. Active tails enhance arboreal acrobatics in geckos

    PubMed Central

    Jusufi, Ardian; Goldman, Daniel I.; Revzen, Shai; Full, Robert J.

    2008-01-01

    Geckos are nature's elite climbers. Their remarkable climbing feats have been attributed to specialized feet with hairy toes that uncurl and peel in milliseconds. Here, we report that the secret to the gecko's arboreal acrobatics includes an active tail. We examine the tail's role during rapid climbing, aerial descent, and gliding. We show that a gecko's tail functions as an emergency fifth leg to prevent falling during rapid climbing. A response initiated by slipping causes the tail tip to push against the vertical surface, thereby preventing pitch-back of the head and upper body. When pitch-back cannot be prevented, geckos avoid falling by placing their tail in a posture similar to a bicycle's kickstand. Should a gecko fall with its back to the ground, a swing of its tail induces the most rapid, zero-angular momentum air-righting response yet measured. Once righted to a sprawled gliding posture, circular tail movements control yaw and pitch as the gecko descends. Our results suggest that large, active tails can function as effective control appendages. These results have provided biological inspiration for the design of an active tail on a climbing robot, and we anticipate their use in small, unmanned gliding vehicles and multisegment spacecraft. PMID:18347344

  8. Digital Imaging: An Adobe Photoshop Course

    ERIC Educational Resources Information Center

    Cobb, Kristine

    2007-01-01

    This article introduces digital imaging, an Adobe Photoshop course at Shrewsbury High School in Shrewsbury, Massachusetts. Students are able to earn art credits to graduate by successfully completing the course. Digital imaging must cover art criteria as well as technical skills. The course begins with tutorials created by the instructor and other…

  9. Apparatus for forming adobe bricks and drilling wells

    SciTech Connect

    Kinnamon, H. D.

    1985-02-12

    An improved apparatus for the continuous and relatively labor-free fabrication of adobe bricks and the forcing of well casings into the earth. With regard to forming adobe bricks, a rotating table carries the bricks being processed from one station to the next and a novel means for applying unusually high forming pressures permits immediate forming and ejection of the bricks from the forms while at the same time producing adobe bricks of improved quality and hardness characteristics.

  10. Protein Synthesis Inhibition Blocks Consolidation of an Acrobatic Motor Skill

    ERIC Educational Resources Information Center

    Kaelin-Lang, Alain; Dichgans, Johannes; Schulz, Jorg B.; Luft, Andreas R.; Buitrago, Manuel M.

    2004-01-01

    To investigate whether motor skill learning depends on de novo protein synthesis, adult rats were trained in an acrobatic locomotor task (accelerating rotarod) for 7 d. Animals were systemically injected with cycloheximide (CHX, 0.5 mg/kg, i.p.) 1 h before sessions 1 and 2 or sessions 2 and 3. Control rats received vehicle injections before…

  11. Astronaut Alan Bean doing acrobatics in OWS dome area

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Astronaut Alan L. Bean, Skylab 3 commander, doing acrobatics in the dome area of the Orbital Workshop (OWS) on the space station cluster in Earth orbit. The dome area is about 22 feet in diameter and 19 feet from top to bottom.

  12. Astronaut Jack Lousma doing acrobatics in OWS dome area

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Astronaut Jack R. Lousma, Skylab 3 pilot, doing acrobatics in the dome area of the Orbital Workshop (OWS) on the space station cluster in Earth orbit. The dome area is about 22 feet in diameter and 19 feet from top to bottom.

  13. 78 FR 48152 - Notice Inviting Publishers To Submit Tests for a Determination of Suitability for Use in the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-07

    ... or by email: Michelle.Meier@ed.gov . If you use a telecommunications device for the deaf (TDD) or a... Register, in text or Adobe Portable Document Format (PDF). To use PDF you must have Adobe Acrobat...

  14. Centre of pressure correlates with pyramid performance in acrobatic gymnastics.

    PubMed

    Floría, Pablo; Gómez-Landero, Luis Arturo; Harrison, Andrew J

    2015-01-01

    Acrobatic gymnasts need excellent balance control to execute pyramids where one gymnast is supported by another. The objectives of this study were: (1) to describe balance performance by assessing the centre of pressure displacement in a group of acrobatic gymnasts executing pyramids; (2) to determine the relationship between the parameters describing the centre of pressure oscillations and pyramid score; and (3) to examine the role of each foot in providing a solid base of support to maintain the balance of the pyramid. Sixteen acrobatic gymnasts grouped in pairs performed a Half pyramid and a Straddle pyramid held for 7 s on two force platforms. Path length, variance, range trajectory, and surface area of the centre of pressure of each foot were examined to analyse the balance of the pyramid. The path length was correlated with the pyramid score (Straddle: p = 0.692 [large]; Half: p = 0.407 [moderate]). There were differences in the functions of each leg to maintain balance, with the non-preferred leg supporting a higher weight of the pyramid while the preferred leg performed control movements to maintain balance. The results suggested that quantitative analysis of balance can provide important information on pyramid performance. PMID:26715236

  15. Characterization, reproduction and optimization of traditional adobe bricks

    NASA Astrophysics Data System (ADS)

    Ioannou, Ioannis; Eftychiou, Marina; Costi de Castrillo, Maria; Illampas, Rogiros

    2013-04-01

    Adobe bricks were first introduced 10-12,000 years ago. Extensive use of the material throughout the centuries has led to strong local traditions of building with earth and has established adobe masonry as an important feature of the international architectural heritage. Today, despite no longer being a prevalent building material, adobes are still in use, since a number of earthen structures survive worldwide. Furthermore, the simplicity, low cost and almost negligible embodied energy associated with the production of adobes, as well as their good thermal and acoustic properties, render them an attractive option for use in contemporary sustainable construction. Therefore, several ongoing research projects internationally investigate the physicochemical and mechanical properties of traditional adobe bricks and the design/production of optimized adobes, with improved characteristics, for use in contemporary architecture. Here, we present ongoing research on adobe bricks carried out in the framework of the project E& IXEIPH EI / POION/0609/41, which is co-funded by the European Regional Development Fund and the Republic of Cyprus, through the Cyprus Research Promotion Foundation. Our work focuses on the characterization of traditional adobes, their reproduction and optimization in the laboratory to produce materials with improved physicomechanical properties. Results up-to-date show that traditional adobes are mostly composed of random quantities of silt and clay. Calcite is also predominant in relevant X-ray diffraction analyses. The average capillary water absorption coefficient (measured against a saturated sponge surface) of samples collected from market suppliers rarely exceeds 1 mm/min1 -2, while their thermal conductivity is around 0.55 W/mK. The response of traditional adobes to compression is characterized by intense deformability. The average compressive strength recorded depends on the form of test specimen (cube, cylinder, prism). Samples with aspect

  16. 20. This adobe building, housing the Phoenix Herald in 1879, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    20. This adobe building, housing the Phoenix Herald in 1879, stood on the site later occupied by the Stroud Building. The Salt River Herald, Phoenix's first newspaper, was founded in 1878; in 1879, it became the Phoenix Herald. Prior to 1879, the adobe building served as the office for a stagecoach line operating between Maricopa and Prescott via Phoenix. Credit PPL. - Stroud Building, 31-33 North Central Avenue, Phoenix, Maricopa County, AZ

  17. Design and Implementation of a Self-Directed Stereochemistry Lesson Using Embedded Virtual Three-Dimensional Images in a Portable Document Format

    ERIC Educational Resources Information Center

    Cody, Jeremy A.; Craig, Paul A.; Loudermilk, Adam D.; Yacci, Paul M.; Frisco, Sarah L.; Milillo, Jennifer R.

    2012-01-01

    A novel stereochemistry lesson was prepared that incorporated both handheld molecular models and embedded virtual three-dimensional (3D) images. The images are fully interactive and eye-catching for the students; methods for preparing 3D molecular images in Adobe Acrobat are included. The lesson was designed and implemented to showcase the 3D…

  18. Rehabilitation of adobe buildings. Understanding different materials from Portugal

    NASA Astrophysics Data System (ADS)

    Costa, Cristiana; Rocha, Fernando; Velosa, Ana

    2016-04-01

    Earth construction is the oldest building material known, with documented cases of the use of earth bricks since Mesopotamia around 10 000 BC (Heathcote, 1995). The earth construction exists throughout the majority of the world in different cultures, and for some countries, nowadays it continues to be the main process of construction (Vega et al, 2011). Around 30% of the world's population lives in buildings made of earth materials. Earthen construction is an environmentally friendly technique with a social and cultural contribution; this advantage is increased when this type of construction is applied in developing countries where the material costs counterbalance with labour costs, and where other materials and techniques cannot be available (Ciancio et al, 2013). Studies of materials characterization are required in order to understand the composition and specific properties of the earth buildings, their heterogeneity and their degradation mechanisms. Some adobes from different buildings, ages and regions of Portugal were collected in order to characterize them (mineralogically, chemically and physically). It was possible to understand the composition of these materials and their differences. Main minerals are quartz, feldspars, calcite and phyllosilicates (mica and kaolinite). The mechanical behaviour of these materials isn't the best, but it is possible to improve it with some simple and cheap natural additives (kaolinitic soils). The characterization of these materials allows us to understand the differences between the materials from the different regions (controlled by locally available raw materials). Understanding these materials, and their properties, it is possible to formulate new ones for repair, conservation and rehabilitation works. The adobe bricks are an alternative of kiln baked bricks which has several advantages and one of the most important is that these materials are recyclable. Adobes are an excellent option for building rehabilitation, if

  19. 14 CFR 21.183 - Issue of standard airworthiness certificates for normal, utility, acrobatic, commuter, and...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... affecting § 21.183, see the List of CFR Sections Affected, which appears in the Finding Aids section of the... certificates for normal, utility, acrobatic, commuter, and transport category aircraft; manned free balloons..., commuter, and transport category aircraft; manned free balloons; and special classes of aircraft. (a)...

  20. 14 CFR 21.183 - Issue of standard airworthiness certificates for normal, utility, acrobatic, commuter, and...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... § 21.183, see the List of CFR Sections Affected, which appears in the Finding Aids section of the... certificates for normal, utility, acrobatic, commuter, and transport category aircraft; manned free balloons..., commuter, and transport category aircraft; manned free balloons; and special classes of aircraft. Link...

  1. 14 CFR 21.183 - Issue of standard airworthiness certificates for normal, utility, acrobatic, commuter, and...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... affecting § 21.183, see the List of CFR Sections Affected, which appears in the Finding Aids section of the... certificates for normal, utility, acrobatic, commuter, and transport category aircraft; manned free balloons..., commuter, and transport category aircraft; manned free balloons; and special classes of aircraft. (a)...

  2. 75 FR 4442 - Public Meeting on Future Policy and Rulemaking for Normal, Utility, Acrobatic, and Commuter...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-27

    ... Federal Aviation Administration Public Meeting on Future Policy and Rulemaking for Normal, Utility, Acrobatic, and Commuter Category Small Airplanes AGENCY: Federal Aviation Administration (FAA), DOT. ACTION... discuss a review of the requirements for small airplanes. This discussion focuses on the future of...

  3. Adobe photoshop quantification (PSQ) rather than point-counting: A rapid and precise method for quantifying rock textural data and porosities

    NASA Astrophysics Data System (ADS)

    Zhang, Xuefeng; Liu, Bo; Wang, Jieqiong; Zhang, Zhe; Shi, Kaibo; Wu, Shuanglin

    2014-08-01

    Commonly used petrological quantification methods are visual estimation, counting, and image analyses. However, in this article, an Adobe Photoshop-based analyzing method (PSQ) is recommended for quantifying the rock textural data and porosities. Adobe Photoshop system provides versatile abilities in selecting an area of interest and the pixel number of a selection could be read and used to calculate its area percentage. Therefore, Adobe Photoshop could be used to rapidly quantify textural components, such as content of grains, cements, and porosities including total porosities and different genetic type porosities. This method was named as Adobe Photoshop Quantification (PSQ). The workflow of the PSQ method was introduced with the oolitic dolomite samples from the Triassic Feixianguan Formation, Northeastern Sichuan Basin, China, for example. And the method was tested by comparing with the Folk's and Shvetsov's "standard" diagrams. In both cases, there is a close agreement between the "standard" percentages and those determined by the PSQ method with really small counting errors and operator errors, small standard deviations and high confidence levels. The porosities quantified by PSQ were evaluated against those determined by the whole rock helium gas expansion method to test the specimen errors. Results have shown that the porosities quantified by the PSQ are well correlated to the porosities determined by the conventional helium gas expansion method. Generally small discrepancies (mostly ranging from -3% to 3%) are caused by microporosities which would cause systematic underestimation of 2% and/or by macroporosities causing underestimation or overestimation in different cases. Adobe Photoshop could be used to quantify rock textural components and porosities. This method has been tested to be precise and accurate. It is time saving compared with usual methods.

  4. Prosthetic Feet

    MedlinePlus

    « View More Amputee Coalition Publications Click here for optional PDF format. Requires Adobe Acrobat Reader Text size Larger text Smaller text ... no single foot that is perfect for every amputee. You and your doctor or prosthetist should choose ...

  5. Building code challenging the ethics behind adobe architecture in North Cyprus.

    PubMed

    Hurol, Yonca; Yüceer, Hülya; Şahali, Öznem

    2015-04-01

    Adobe masonry is part of the vernacular architecture of Cyprus. Thus, it is possible to use this technology in a meaningful way on the island. On the other hand, although adobe architecture is more sustainable in comparison to other building technologies, the use of it is diminishing in North Cyprus. The application of Turkish building code in the north of the island has created complications in respect of the use of adobe masonry, because this building code demands that reinforced concrete vertical tie-beams are used together with adobe masonry. The use of reinforced concrete elements together with adobe masonry causes problems in relation to the climatic response of the building as well as causing other technical and aesthetic problems. This situation makes the design of adobe masonry complicated and various types of ethical problems also emerge. The objective of this article is to analyse the ethical problems which arise as a consequence of the restrictive character of the building code, by analysing two case studies and conducting an interview with an architect who was involved with the use of adobe masonry in North Cyprus. According to the results of this article there are ethical problems at various levels in the design of both case studies. These problems are connected to the responsibilities of architects in respect of the social benefit, material production, aesthetics and affordability of the architecture as well as presenting distrustful behaviour where the obligations of architects to their clients is concerned. PMID:24696019

  6. The development of a new edition of the gamma-ray spectrum catalogues designed for presentation in electronic format

    SciTech Connect

    Heath, R.L.

    1997-11-01

    New editions of the original Gamma-ray Spectrum Catalogues are being prepared for publication in electronic format. The objective of this program is to produce versions of the Catalogues in CD-ROM format and as an Internet resource. Additions to the original content of the Catalogues will include integrated decay scheme drawings, tables of related decay data, and updated text on the techniques of gamma-ray spectrometry. Related decay data from the Evaluated Nuclear Structure Data File (ENSDF) are then added, and all data converted to the Adobe Acrobat (PDF) format for CD-ROM production and availability on the large-volume Ge detectors, alpha-particle spectra, prompt neutron capture and inelastic scattering gamma-ray spectra, and gross fission product spectra characteristic of fuel cycle waste materials. Characterization of radioactivity in materials is a requirement in many phases of radioactive waste management. Movement, shipping, treatment, all activities which involve handling of mixed waste or TRU categories of waste at all DOE sites will require that measurements and assessment documentation utilize basic nuclear data which are tracable to internationally accepted standard values. This program will involve the identification of data needs unique to the development and application of specialized detector systems for radioactive waste characterization. 8 refs., 8 figs.

  7. Speciation and bioaccessibility of mercury in adobe bricks and dirt floors in Huancavelica, Peru

    EPA Science Inventory

    Background: Huancavelica, Peru, a historic cinnabar refining site, is one of the most mercury (Hg) contaminated urban areas in the world. Residents’ exposures are amplified because residents build their adobe brick homes from contaminated soil. Objectives: The objectives of th...

  8. Distinct neuroplasticity processes are induced by different periods of acrobatic exercise training.

    PubMed

    Salame, Samira; Garcia, Priscila C; Real, Caroline C; Borborema, Juliana; Mota-Ortiz, Sandra R; Britto, Luiz R G; Pires, Raquel S

    2016-07-15

    Short and long-term physical exercise induce physiological and structural changes in brain motor areas. The relationship between changes of structural and synaptic proteins in brain motor areas and acrobatic exercise is less understood. Our aim was to evaluate the expression of synapsin I (SYS), synaptophysin (SYP), microtubule-associated protein 2 (MAP2), neurofilament (NF), and a marker for recent neuronal activity (Egr-1) in the motor cortex, striatum and cerebellum of adult rats subjected to acrobatic exercise (AE, for 1-4 weeks). We used adult Wistar rats, divided into 4 groups based on duration of acrobatic training, namely 1 week (AE1, n=15), 2 weeks (AE2, n=15), 4 weeks (AE4, n=15), and sedentary (SED, n=15). In AE groups, the rats covered 5 times a circuit that was composed of obstacles, three times a week. The protein levels were analyzed by immunoblotting and immunohistochemistry. The results revealed that short-term AE (AE1 and AE2) induced MAP2 decreases and NF, SYP and Egr-1 increases in the motor cortex; an increase of MAP2, SYS and SYP in the dorsolateral striatum, whereas the dorsomedial striatum showed increased NF, SYS, SYP and Egr-1. Granular cerebellar layer showed increased NF and Egr-1, with increased NF and SYP in the molecular layer. Long-term AE (AE4) promoted an increase of MAP2, SYP and Egr-1 in motor cortex; MAP2, SYS and SYP in the dorsomedial striatum; and NF and Egr-1 in the cerebellar granular layer. In conclusion, our data suggest that different durations of AE induce distinct plastic responses among distinct cortical and subcortical circuits. PMID:27126278

  9. 14 CFR 21.21 - Issue of type certificate: normal, utility, acrobatic, commuter, and transport category aircraft...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Issue of type certificate: normal, utility, acrobatic, commuter, and transport category aircraft; manned free balloons; special classes of aircraft; aircraft engines; propellers. 21.21 Section 21.21 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION...

  10. 14 CFR 21.21 - Issue of type certificate: normal, utility, acrobatic, commuter, and transport category aircraft...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...; aircraft engines; propellers. 21.21 Section 21.21 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT CERTIFICATION PROCEDURES FOR PRODUCTS AND PARTS Type Certificates § 21.21 Issue of type certificate: normal, utility, acrobatic, commuter, and transport category...

  11. 14 CFR 21.21 - Issue of type certificate: normal, utility, acrobatic, commuter, and transport category aircraft...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...; aircraft engines; propellers. 21.21 Section 21.21 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT CERTIFICATION PROCEDURES FOR PRODUCTS AND PARTS Type Certificates § 21.21 Issue of type certificate: normal, utility, acrobatic, commuter, and transport category...

  12. 14 CFR 21.21 - Issue of type certificate: normal, utility, acrobatic, commuter, and transport category aircraft...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...; aircraft engines; propellers. 21.21 Section 21.21 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT CERTIFICATION PROCEDURES FOR PRODUCTS AND PARTS Type Certificates § 21.21 Issue of type certificate: normal, utility, acrobatic, commuter, and transport category...

  13. 14 CFR 21.21 - Issue of type certificate: normal, utility, acrobatic, commuter, and transport category aircraft...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...; aircraft engines; propellers. 21.21 Section 21.21 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT CERTIFICATION PROCEDURES FOR PRODUCTS AND PARTS Type Certificates § 21.21 Issue of type certificate: normal, utility, acrobatic, commuter, and transport category...

  14. Using Adobe Flash Animations of Electron Transport Chain to Teach and Learn Biochemistry

    ERIC Educational Resources Information Center

    Teplá, Milada; Klímová, Helena

    2015-01-01

    Teaching the subject of the electron transport chain is one of the most challenging aspects of the chemistry curriculum at the high school level. This article presents an educational program called "Electron Transport Chain" which consists of 14 visual animations including a biochemistry quiz. The program was created in the Adobe Flash…

  15. Using Adobe Connect to Deliver Online Library Instruction to the RN to BSN Program

    ERIC Educational Resources Information Center

    Carlson, Kathleen

    2011-01-01

    This paper takes a look at how one academic health sciences librarian brought mediated literature searching to the distance RN to BSN nursing students. It takes a look at why Adobe Connect was the webinar software that was selected to deliver online instruction to the students. The article explains how students participated in a pre-class survey…

  16. Staying on Top of Your Game and Scoring Big with Adobe Presenter Multimedia Tutorials

    ERIC Educational Resources Information Center

    Koury, Regina; Francis, Marcia J.; Gray, Catherine J.; Jardine, Spencer J.; Guo, Ruiling

    2010-01-01

    In order to reach distance students in times of financial uncertainty, librarians must be creative. While much has been written about Camtasia, Captivate and Jing tutorial software, Adobe Presenter, a Microsoft PowerPoint plug-in, has not been discussed. This article describes how our library team created multimedia tutorial projects at Idaho…

  17. Building on Tradition: The Art of Adobe and the Revival of Community.

    ERIC Educational Resources Information Center

    Crocker, Amanda; Swan, Susan

    2001-01-01

    A New Mexico foundation helps primarily Hispanic and American Indian communities restore adobe churches by supplying technical assistance and matching grants. Community leadership of the projects enhances volunteer commitment. The projects build community cohesiveness and pride, maintain local culture, foster intergenerational relations, teach…

  18. Vector Graphics for Web Lectures: Experiences with Adobe Flash 9 and SVG

    ERIC Educational Resources Information Center

    Ketterl, Markus; Mertens, Robert; Vornberger, Oliver

    2007-01-01

    Purpose: The purpose of this paper is to describe vector graphics for web lectures, focusing on the experiences with Adobe Flash 9 and SVG. Design/methodology/approach: The paper presents experiences made during the development and everyday use of two versions of the lecture-recording system virtPresenter. The first of these versions is based on…

  19. Enriching Learning for First Year Chemistry Students: Introduction of Adobe Connect

    ERIC Educational Resources Information Center

    Smith, Erica; Lye, Peter; Greatrex, Ben; Taylor, Michelle; Stupans, Ieva

    2013-01-01

    The study of chemistry is central within science and other associated degrees. At the University of New England in Armidale academics need to provide chemistry teaching in both a distance and the traditional on-campus mode within science and other degrees. This study explores the contribution that the adoption of Adobe Connect technology can make…

  20. Kinematic and kinetic analysis of two gymnastics acrobatic series to performing the backward stretched somersault.

    PubMed

    Mkaouer, Bessem; Jemni, Monèm; Amara, Samiha; Chaabène, Helmi; Tabka, Zouhair

    2013-01-01

    Back swing connections during gymnastics acrobatic series considerably influence technical performance and difficulties, particularly in the back somersault. The aim of this study was to compare the take-off's kinetic and kinematic variables between two acrobatic series leading to perform the backward stretched somersault (also called salto): round-off, flic-flac to stretched salto versus round-off, tempo-salto to stretched salto. Five high level male gymnasts (age 23.17 ± 1.61 yrs; body height 1.65 ± 0.05 m; body mass 56.80 ± 7.66 kg) took part in this investigation. A force plate synchronized with a two dimensional movement analysis system was used to collect kinetic and kinematic data. Statistical analysis via the non-parametric Wilcoxon Rank-sum test showed significant differences between the take-offs' variables. The backswing connections were different in the take-off angle, linear momentum, vertical velocity and horizontal and vertical displacements. In conclusion, considering that the higher elevation of the centre of mass in the flight phase would allow best performance and lower the risk of falls, particularly when combined to a great angular momentum, this study demonstrated that the optimal connection series was round-off, flic-flac to stretched salto which enabled the best height in the somersault. Analysis of the results suggests that both connections facilitate the performance of single and double (or triple) backward somersaults with or without rotations around the longitudinal axis. Gymnasts could perform these later while gaining height if they chose the round-off, flic-flac technique or gaining some backward displacement if they choose the round-off, salto tempo. PMID:24146701

  1. Kinematic and Kinetic Analysis of Two Gymnastics Acrobatic Series to Performing the Backward Stretched Somersault

    PubMed Central

    Mkaouer, Bessem; Jemni, Monèm; Amara, Samiha; Chaabène, Helmi; Tabka, Zouhair

    Back swing connections during gymnastics acrobatic series considerably influence technical performance and difficulties, particularly in the back somersault. The aim of this study was to compare the take-off’s kinetic and kinematic variables between two acrobatic series leading to perform the backward stretched somersault (also called salto): round-off, flic-flac to stretched salto versus round-off, tempo-salto to stretched salto. Five high level male gymnasts (age 23.17 ± 1.61 yrs; body height 1.65 ± 0.05 m; body mass 56.80 ± 7.66 kg) took part in this investigation. A force plate synchronized with a two dimensional movement analysis system was used to collect kinetic and kinematic data. Statistical analysis via the non-parametric Wilcoxon Rank-sum test showed significant differences between the take-offs’ variables. The backswing connections were different in the take-off angle, linear momentum, vertical velocity and horizontal and vertical displacements. In conclusion, considering that the higher elevation of the centre of mass in the flight phase would allow best performance and lower the risk of falls, particularly when combined to a great angular momentum, this study demonstrated that the optimal connection series was round-off, flic-flac to stretched salto which enabled the best height in the somersault. Analysis of the results suggests that both connections facilitate the performance of single and double (or triple) backward somersaults with or without rotations around the longitudinal axis. Gymnasts could perform these later while gaining height if they chose the round-off, flic-flac technique or gaining some backward displacement if they choose the round-off, salto tempo. PMID:24146701

  2. Peripheral androgen receptors sustain the acrobatics and fine motor skill of elaborate male courtship.

    PubMed

    Fuxjager, Matthew J; Longpre, Kristy M; Chew, Jennifer G; Fusani, Leonida; Schlinger, Barney A

    2013-09-01

    Androgenic hormones regulate many aspects of animal social behavior, including the elaborate display routines on which many species rely for advertisement and competition. One way that this might occur is through peripheral effects of androgens, particularly on skeletal muscles that control complex movements and postures of the body and its limbs. However, the specific contribution of peripheral androgen-muscle interactions to the performance of elaborate behavioral displays in the natural world has never been examined. We study this issue in one of the only natural physiological models of animal acrobatics: the golden-collared manakin (Manacus vitellinus). In this tropical bird, males compete with each other and court females by producing firecracker-like wing- snaps and by rapidly dancing among saplings over the forest floor. To test how activation of peripheral androgen receptors (AR) influences this display, we treat reproductively active adult male birds with the peripherally selective antiandrogen bicalutamide (BICAL) and observe the effects of this manipulation on male display performance. We not only validate the peripheral specificity of BICAL in this species, but we also show that BICAL treatment reduces the frequency with which adult male birds perform their acrobatic display maneuvers and disrupts the overall structure and fine-scale patterning of these birds' main complex wing-snap sonation. In addition, this manipulation has no effect on the behavioral metrics associated with male motivation to display. Together, our findings help differentiate the various effects of peripheral and central AR on the performance of a complex sociosexual behavioral phenotype by indicating that peripheral AR can optimize the motor skills necessary for the production of an elaborate animal display. PMID:23782945

  3. Speciation and bioaccessibility of mercury in adobe bricks and dirt floors in Huancavelica, Peru.

    PubMed

    Hagan, Nicole; Robins, Nicholas; Gonzales, Ruben Dario Espinoza; Hsu-Kim, Heileen

    2015-04-01

    Huancavelica, Peru, a historic cinnabar refining site, is one of the most mercury (Hg)-contaminated urban areas in the world. Exposure is amplified because residents build their adobe brick homes from contaminated soil. The objectives of this study were to compare two Hg-leaching procedures, and their application as risk-assessment screening tools in Hg-contaminated adobe brick homes in Huancavelica. The purpose was to evaluate potential health implications, particularly for children, after ingestion of Hg-contaminated particles. Hg was measured in adobe brick and dirt floor samples from 60 households by total Hg extraction, simulated gastric fluid (GF) extraction, and sequential selective extraction (SSE), which provides more detailed data but is resource-intensive. Most of the Hg present in samples was relatively insoluble, although in some households soluble Hg species were present at concentrations that may be of concern after ingestion. A strong correlation was identified between results from simulated GF extraction of adobe bricks and dirt floors and the more soluble fractions of Hg from SSE. Simulated GF extraction data were combined with ingestion and body mass characteristics for small children to compare potential risk of ingestion of Hg-contaminated soil with current health standards. Simulated GF extraction can be used as a risk assessment screening tool for effective allocation of time and resources to households that have measurable concentrations of bioaccessible Hg. Combining simulated GF extraction data with health standards enables intervention strategies targeted at households with the greatest potential health threat from ingestion of Hg-contaminated particles. PMID:25169738

  4. USEFULNESS AND METABOLIC IMPLICATIONS OF A 60-SECOND REPEATED JUMPS TEST AS A PREDICTOR OF ACROBATIC JUMPING PERFORMANCE IN GYMNASTS

    PubMed Central

    Rodríguez, F.A.

    2013-01-01

    Gymnastics floor exercises are composed of a set of four to five successive acrobatic jumps usually called a “series”. The aims of the study were: 1) to relate the acrobatic gymnastics performance of these series with a repeated jumps test of similar duration (R60), 2) to study the relation between R60 and physiological parameters (heart rate and blood lactate), and the performance obtained in different kinds of jumps, 3) to confirm whether R60, executed without a damped jumping technique, can be considered an anaerobic lactic power test. Twenty male and twenty-four female gymnasts performed three repeated jumps tests for 5 s (R5), 10 s (R10) and 60 s (R60) and vertical jumps, such as drop jumps (DJ), squat jumps (SJ) and countermovement jumps (CMJ). We assessed heart rate (HR) and blood lactate during R10 and R60. The average values of the maximal blood lactate concentration (Lmax) after R10 (males = 2.5±0.6 mmol · l−1; females = 2.1±0.8 mmol · l−1) confirm that anaerobic glycolysis is not activated to a high level. In R60, the Lmax (males = 7.5±1.7 mmol · l−1 females = 5.9±2.1 mmol · l−1) that was recorded does not validate R60 as an anaerobic lactic power test. We confirmed the relation between the average power obtained in R60 (R60Wm) and the acrobatic performance on the floor. The inclusion in the multiple regression equation of the best power in DJ and the best flight-contact ratio (FC) in R5 confirms the influence of other non-metabolic components on the variability in R60 performance, at least in gymnasts. PMID:24744459

  5. Adobe InDesign vs. QuarkXPress and PageMaker: The Best of Both Worlds?

    ERIC Educational Resources Information Center

    Wilson, Bradley

    2000-01-01

    Evaluates the newly released Adobe InDesign software, finding that while it brings new life into desktop publishing, it is not yet a "must buy" for publications advisers. Compares specific features that are relevant for student publications, including: character, paragraph, drop caps, define styles, page setup, text wrap, defining and using…

  6. FES Documentation - Cancer Imaging Program

    Cancer.gov

    The FES documentation files are presented in Adobe Acrobat or Word files, either in executable or ZIP format to be maximally compatible with the computer system being downloaded into. The files are large in any format and should be downloaded with a fast Internet link.

  7. Residential metal contamination and potential health risks of exposure in adobe brick houses in Potosí, Bolivia.

    PubMed

    McEwen, Abigail R; Hsu-Kim, Heileen; Robins, Nicholas A; Hagan, Nicole A; Halabi, Susan; Barras, Olivo; Richter, Daniel deB; Vandenberg, John J

    2016-08-15

    Potosí, Bolivia, is the site of centuries of historic and present-day mining of the Cerro Rico, a mountain known for its rich polymetallic deposits, and was the site of large-scale Colonial era silver refining operations. In this study, the concentrations of several metal and metalloid elements were quantified in adobe brick, dirt floor, and surface dust samples from 49 houses in Potosí. Median concentrations of total mercury (Hg), lead (Pb), and arsenic (As) were significantly greater than concentrations measured in Sucre, Bolivia, a non-mining town, and exceeded US-based soil screening levels. Adobe brick samples were further analyzed for bioaccessible concentrations of trace elements using a simulated gastric fluid (GF) extraction. Median GF extractable concentrations of Hg, As, and Pb were 0.085, 13.9, and 32.2% of the total element concentration, respectively. Total and GF extractable concentrations of Hg, As, and Pb were used to estimate exposure and potential health risks to children following incidental ingestion of adobe brick particles. Risks were assessed using a range of potential ingestion rates (50-1000mg/day). Overall, the results of the risk assessment show that the majority of households sampled contained concentrations of bioaccessible Pb and As, but not Hg, that represent a potential health risk. Even at the lowest ingestion rate considered, the majority of households exceeded the risk threshold for Pb, indicating that the concentrations of this metal are of particular concern. To our knowledge, this is the first study to quantify key trace elements in building materials in adobe brick houses and the results indicate that these houses are a potential source of exposure to metals and metalloids in South American mining communities. Additional studies are needed to fully characterize personal exposure and to understand potential adverse health outcomes within the community. PMID:27100004

  8. Auditory presentation and synchronization in Adobe Flash and HTML5/JavaScript Web experiments.

    PubMed

    Reimers, Stian; Stewart, Neil

    2016-09-01

    Substantial recent research has examined the accuracy of presentation durations and response time measurements for visually presented stimuli in Web-based experiments, with a general conclusion that accuracy is acceptable for most kinds of experiments. However, many areas of behavioral research use auditory stimuli instead of, or in addition to, visual stimuli. Much less is known about auditory accuracy using standard Web-based testing procedures. We used a millisecond-accurate Black Box Toolkit to measure the actual durations of auditory stimuli and the synchronization of auditory and visual presentation onsets. We examined the distribution of timings for 100 presentations of auditory and visual stimuli across two computers with difference specs, three commonly used browsers, and code written in either Adobe Flash or JavaScript. We also examined different coding options for attempting to synchronize the auditory and visual onsets. Overall, we found that auditory durations were very consistent, but that the lags between visual and auditory onsets varied substantially across browsers and computer systems. PMID:27421976

  9. Using Adobe Flash animations of electron transport chain to teach and learn biochemistry.

    PubMed

    Teplá, Milada; Klímová, Helena

    2015-01-01

    Teaching the subject of the electron transport chain is one of the most challenging aspects of the chemistry curriculum at the high school level. This article presents an educational program called "Electron Transport Chain" which consists of 14 visual animations including a biochemistry quiz. The program was created in the Adobe Flash CS3 Professional animation program and is designed for high school chemistry students. Our goal is to develop educational materials that facilitate the comprehension of this complex subject through dynamic animations which show the course of the electron transport chain and simultaneously explain its nature. We record the process of the electron transport chain, including connections with oxidative phosphorylation, in such a way as to minimize the occurrence of discrepancies in interpretation. The educational program was evaluated in high schools through the administration of a questionnaire, which contained 12 opened-ended items and which required participants to evaluate the graphics of the animations, chemical content, student preferences, and its suitability for high school biochemistry teaching. PMID:25846233

  10. Radon and thoron levels, their spatial and seasonal variations in adobe dwellings - a case study at the great Hungarian plain.

    PubMed

    Szabó, Zsuzsanna; Jordan, Gyozo; Szabó, Csaba; Horváth, Ákos; Holm, Óskar; Kocsy, Gábor; Csige, István; Szabó, Péter; Homoki, Zsolt

    2014-06-01

    Radon and thoron isotopes are responsible for approximately half of the average annual effective dose to humans. Although the half-life of thoron is short, it can potentially enter indoor air from adobe walls. Adobe was a traditional construction material in the Great Hungarian Plain. Its major raw materials are the alluvial sediments of the area. Here, seasonal radon and thoron activity concentrations were measured in 53 adobe dwellings in 7 settlements by pairs of etched track detectors. The results show that the annual average radon and thoron activity concentrations are elevated in these dwellings and that the proportions with values higher than 300 Bq m(-3) are 14-17 and 29-32% for radon and thoron, respectively. The calculated radon inhalation dose is significantly higher than the world average value, exceeding 10 mSv y(-1) in 7% of the dwellings of this study. Thoron also can be a significant contributor to the inhalation dose with about 30% in the total inhalation dose. The changes of weather conditions seem to be more relevant in the variation of measurement results than the differences in the local sedimentary geology. Still, the highest values were detected on clay. Through the year, radon follows the average temperature changes and is affected by the ventilation, whereas thoron rather seems to follow the amount of precipitation. PMID:24437932

  11. 78 FR 27959 - Defense Legal Policy Board; Notice of Federal Advisory Committee Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-13

    ... Federal Officer given in this notice in the following formats: Adobe Acrobat, WordPerfect, or Microsoft... May 30, 2013. The Public Session will begin at 9:00 a.m. and end at 4:30 p.m. FOR FURTHER INFORMATION... Materials for the Meeting: A copy of the agenda for the May 30, 2013 meeting and the tasking for...

  12. The ABCs of PDFs.

    ERIC Educational Resources Information Center

    Adler, Steve

    2000-01-01

    Explains the use of Adobe Acrobat's Portable Document Format (PDF) for school Web sites and Intranets. Explains the PDF workflow; components for Web-based PDF delivery, including the Web server, preparing content of the PDF files, and the browser; incorporating PDFs into the Web site; incorporating multimedia; and software. (LRW)

  13. Prosthetic Knee Systems

    MedlinePlus

    « View More Amputee Coalition Publications Click here for optional PDF format. Requires Adobe Acrobat Reader Text size Larger text Smaller text ... from. Doctors, prosthetists and rehabilitation specialists consider an amputee’s age, health, activity level, and lifestyle when making ...

  14. 47 CFR 1.1705 - Forms; electronic and manual filing.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Forms; electronic and manual filing. 1.1705... Operations and Licensing System (COALS) § 1.1705 Forms; electronic and manual filing. (a) Application forms... via COALS in Adobe Acrobat Portable Document Format (PDF) whenever possible. (c) Manual filing....

  15. 76 FR 39104 - Science Advisory Board Staff Office; Notification of a Public Teleconference of the Chartered...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-05

    ... situation is called a ``partial lead service line replacement.'' OW has requested the SAB to review and... electronic formats: Adobe Acrobat PDF, MS Word, MS PowerPoint, or Rich Text files in IBM-PC/Windows 98/2000... SAB Staff Office procedural policies. Background: Exposure to lead through drinking water...

  16. Surgical Correction of Posttraumatic Scapulothoracic Bursitis, Rhomboid Major Muscle Injury, Ipsilateral Glenohumeral Instability, and Headaches Resulting from Circus Acrobatic Maneuvers

    PubMed Central

    Skedros, John G.; Langston, Tanner D.; Phippen, Colton M.

    2015-01-01

    We report the case of a 28-year-old transgender (male-to-female) patient that had a partial tear of the rhomboid major tendon, scapulothoracic bursitis, and glenohumeral instability on the same side. These conditions resulted from traumatic events during circus acrobatic maneuvers. Additional aspects of this case that make it unique include (1) the main traumatic event occurred during a flagpole exercise, where the patient's trunk was suspended horizontally while a vertical pole was grasped with both hands, (2) headaches were associated with the periscapular injury and they improved after scapulothoracic bursectomy and rhomboid tendon repair, (3) surgical correction was done during the same operation with an open anterior capsular-labral reconstruction, open scapulothoracic bursectomy without bone resection, and rhomboid tendon repair, (4) a postoperative complication of tearing of the serratus anterior and rhomboid muscle attachments with recurrent scapulothoracic pain occurred from patient noncompliance, and (5) the postoperative complication was surgically corrected and ultimately resulted in an excellent outcome at the one-year final follow-up. PMID:26273484

  17. Presentation and response timing accuracy in Adobe Flash and HTML5/JavaScript Web experiments.

    PubMed

    Reimers, Stian; Stewart, Neil

    2015-06-01

    Web-based research is becoming ubiquitous in the behavioral sciences, facilitated by convenient, readily available participant pools and relatively straightforward ways of running experiments: most recently, through the development of the HTML5 standard. Although in most studies participants give untimed responses, there is a growing interest in being able to record response times online. Existing data on the accuracy and cross-machine variability of online timing measures are limited, and generally they have compared behavioral data gathered on the Web with similar data gathered in the lab. For this article, we took a more direct approach, examining two ways of running experiments online-Adobe Flash and HTML5 with CSS3 and JavaScript-across 19 different computer systems. We used specialist hardware to measure stimulus display durations and to generate precise response times to visual stimuli in order to assess measurement accuracy, examining effects of duration, browser, and system-to-system variability (such as across different Windows versions), as well as effects of processing power and graphics capability. We found that (a) Flash and JavaScript's presentation and response time measurement accuracy are similar; (b) within-system variability is generally small, even in low-powered machines under high load; (c) the variability of measured response times across systems is somewhat larger; and (d) browser type and system hardware appear to have relatively small effects on measured response times. Modeling of the effects of this technical variability suggests that for most within- and between-subjects experiments, Flash and JavaScript can both be used to accurately detect differences in response times across conditions. Concerns are, however, noted about using some correlational or longitudinal designs online. PMID:24903687

  18. Influence of geological features (geochemistry and mineralogy) of soil wich constitutes adobes in their durability - Huambo, Angola.

    NASA Astrophysics Data System (ADS)

    Duarte, Isabel; Pedro, Elsa; Varum, Humberto; Mirão, José; Pinho, António

    2014-05-01

    After long years of war, great efforts have been made for the socio-economic development of Angola, mainly in the construction industry. Among the construction techniques, the Adobe is the most used in the province of Huambo, especially by low-income families, which constitute the majority. This technique was established as a historical heritage in the culture of that population. The Huambo province is located in the central region of Angola (Central Plateau) and is bounded on the northeast and east by the province of Bié, on the south and southern by province of Huila, and on the west by the province of Benguela and on the northwest by the province of Kwanza Sul. Has an area of 35,771 km2 and approximately 2,301,524 inhabitants, which corresponds to 58 inhabitants per km2 (Government of the Province of Huambo, 2006). The buildings in this province, particularly in rural areas, were deeply marked by war. Given the current scenario of development of the country and considering the possibility of integrate systems and traditional building materials, that respect the environment and fit harmoniously into its natural habitat, one of the alternative options in the actual construction, undergoes resume old solutions and traditional materials such as adobe construction.It is in this context that this project is part of a scientific research in order to permit the improvement and optimization of these traditional solutions, responding to current demands for social, economic and environmental sustainability. The adobe is a building element with potential degradation by water. Due to the climate, subtropical, hot and humid, and geomorphology of the province, about 1000 to 2000 meters of altitude and an extensive river system, these buildings can be vulnerable and present early degradation, exacerbated by lack of knowledge of the properties of geomaterials used and techniques that allow their stabilization and conservation. This paper aims to study the influence of

  19. Creating an Interactive PDF

    ERIC Educational Resources Information Center

    Branzburg, Jeffrey

    2008-01-01

    There are many ways to begin a PDF document using Adobe Acrobat. The easiest and most popular way is to create the document in another application (such as Microsoft Word) and then use the Adobe Acrobat software to convert it to a PDF. In this article, the author describes how he used Acrobat's many tools in his project--an interactive…

  20. Electrical Resistivity Tomographies on the detection of adobe buried archaeological structures in Piramide Sur in Cahuachi (Peru)

    NASA Astrophysics Data System (ADS)

    Capozzoli, L.; Masini, N.; Rizzo, E.; Lasaponara, R.; Orefici, G.

    2012-04-01

    During the last two decades of excavations, adobe pyramids dating back from the 6th century B.C. to the 4th century A.D have been unearthed in the ancient Ceremonial Centre of Cahuachi near Nasca (Peru) by an Italian-Peruvian mission directed by Giuseppe Orefici. One of the archaeological sectors, called sector A, has been almost excavated and restored. To complete sector A only a terraced mound named "Piramide Sur" needs to be excavated. In order to provide useful information on the presence of buried structures and platforms as well on the geological stratigraphy a multi-scale approach based on the integration of satellite remote sensing with geophysical techniques was employed. Such investigations were carried out by the Italian mission ITACA, funded by the Italian Ministry Affairs and composed of researchers of two institutes of CNR (IMAA and IBAM), which provides a scientific support for archaeological research, since 2007. In particular, the subsurface features were investigated by Geoelectrical prospecting, performed by using a georesistivimeter for tomography which observe the resistivity value along sections. Several tomographies were carried out to investigate the shallow and deep structure of the pyramid both along the main flank at Nord and on the top. Finally, the integration of all data acquired by the different remote sensing techniques allowed for spatially characterizing the archaeological features, thus providing important information for the planning of the next archaeological campaign.

  1. Vertical Tail Buffeting Alleviation Using Piezoelectric Actuators: Some Results of the Actively Controlled Response of Buffet-Affected Tails (ACROBAT) Program

    NASA Technical Reports Server (NTRS)

    Moses, Robert W.

    1997-01-01

    A 1/6-scale F-18 wind-tunnel model was tested in the Transonic Dynamics Tunnel at the NASA Langley Research Center as part of the Actively Controlled Response Of Buffet Affected Tails (ACROBAT) program to assess the use of active controls in reducing vertical tail buffeting. The starboard vertical tail was equipped with an active rudder and the port vertical tail was equipped with piezoelectric actuators. The tunnel conditions were atmospheric air at a dynamic pressure of 14 psf. By using single-input-single-output control laws at gains well below the physical limits of the actuators, the power spectral density of the root strains at the frequency of the first bending mode of the vertical tail was reduced by as much as 60 percent up to angles of attack of 37 degrees. Root mean square (RMS) values of root strain were reduced by as much as 19 percent. Buffeting alleviation results when using the rudder are presented for comparison. Stability margins indicate that a constant gain setting in the control law may be used throughout the range of angle of attack tested.

  2. The Rules of Aggression: How Genetic, Chemical and Spatial Factors Affect Intercolony Fights in a Dominant Species, the Mediterranean Acrobat Ant Crematogaster scutellaris

    PubMed Central

    Frizzi, Filippo; Ciofi, Claudio; Dapporto, Leonardo; Natali, Chiara; Chelazzi, Guido; Turillazzi, Stefano; Santini, Giacomo

    2015-01-01

    Nest-mate recognition plays a key role in the biology of ants. Although individuals coming from a foreign nest are, in most cases, promptly rejected, the degree of aggressiveness towards non nest-mates may be highly variable among species and relies on genetic, chemical and environmental factors. We analyzed intraspecific relationships among neighboring colonies of the dominant Mediterranean acrobat ant Crematogaster scutellaris integrating genetic, chemical and behavioral analyses. Colony structure, parental relationships between nests, cuticular hydrocarbons profiles (CHCs) and aggressive behavior against non nest-mates were studied in 34 nests located in olive tree trunks. Bayesian clustering analysis of allelic variation at nine species-specific microsatellite DNA markers pooled nests into 14 distinct clusters, each representing a single colony, confirming a polydomous arrangement of nests in this species. A marked genetic separation among colonies was also detected, probably due to long distance dispersion of queens and males during nuptial flights. CHCs profiles varied significantly among colonies and between nests of the same colony. No relationship between CHCs profiles and genetic distances was detected. The level of aggressiveness between colonies was inversely related to chemical and spatial distance, suggesting a ‘nasty neighbor’ effect. Our findings also suggest that CHCs profiles in C. scutellaris may be linked to external environmental factors rather than genetic relationships. PMID:26445245

  3. The Rules of Aggression: How Genetic, Chemical and Spatial Factors Affect Intercolony Fights in a Dominant Species, the Mediterranean Acrobat Ant Crematogaster scutellaris.

    PubMed

    Frizzi, Filippo; Ciofi, Claudio; Dapporto, Leonardo; Natali, Chiara; Chelazzi, Guido; Turillazzi, Stefano; Santini, Giacomo

    2015-01-01

    Nest-mate recognition plays a key role in the biology of ants. Although individuals coming from a foreign nest are, in most cases, promptly rejected, the degree of aggressiveness towards non nest-mates may be highly variable among species and relies on genetic, chemical and environmental factors. We analyzed intraspecific relationships among neighboring colonies of the dominant Mediterranean acrobat ant Crematogaster scutellaris integrating genetic, chemical and behavioral analyses. Colony structure, parental relationships between nests, cuticular hydrocarbons profiles (CHCs) and aggressive behavior against non nest-mates were studied in 34 nests located in olive tree trunks. Bayesian clustering analysis of allelic variation at nine species-specific microsatellite DNA markers pooled nests into 14 distinct clusters, each representing a single colony, confirming a polydomous arrangement of nests in this species. A marked genetic separation among colonies was also detected, probably due to long distance dispersion of queens and males during nuptial flights. CHCs profiles varied significantly among colonies and between nests of the same colony. No relationship between CHCs profiles and genetic distances was detected. The level of aggressiveness between colonies was inversely related to chemical and spatial distance, suggesting a 'nasty neighbor' effect. Our findings also suggest that CHCs profiles in C. scutellaris may be linked to external environmental factors rather than genetic relationships. PMID:26445245

  4. Prototype biosphere: adobe habitat

    SciTech Connect

    Merdler, S.

    1981-01-01

    The emerging awareness of residential design values focusing on the local environment, resource recycling, energy efficiency and self sustaining attributes is explored. A site-specific example where many of these values are considered is presented.

  5. Vertical Tail Buffeting Alleviation Using Piezoelectric Actuators-Some Results of the Actively Controlled Response of Buffet-Affected Tails (ACROBAT) Program

    NASA Technical Reports Server (NTRS)

    Moses, Robert W.

    1997-01-01

    Buffet is an aeroelastic phenomenon associated with high performance aircraft especially those with twin vertical tails. In particular, for the F/A-18 aircraft at high angles of attack, vortices emanating from wing/fuselage leading edge extensions burst, immersing the vertical tails in their wake. The resulting buffet loads on the vertical tails are a concern from fatigue and inspection points of view. Recently, a 1/6-scale F-18 wind-tunnel model was tested in the Transonic Dynamics Tunnel at the NASA Langley Research Center as part of the Actively Controlled Response Of Buffet Affected Tails (ACROBAT) Program to assess the use of active controls in reducing vertical tail buffeting. The starboard vertical tail was equipped with an active rudder and the port vertical tail was equipped with piezoelectric actuators. The tunnel conditions were atmospheric air at Mach 0.10. By using single-input-single-output control laws at gains well below the physical limits of the actuators, the power spectral density of the root strains at the frequency of the first bending mode of the vertical tail was reduced by as much as 60 percent up to angles of attack of 37 degrees. Root mean square (RMS) values of root strain were reduced by as much as 19 percent. The results herein illustrate that buffet alleviation of vertical tails can be accomplished using simple active control of the rudder or piezoelectric actuators. In fact, as demonstrated herein, a fixed gain single input single output control law that commands piezoelectric actuators may be active throughout the high angle-of-attack maneuver without requiring any changes during the maneuver. Future tests are mentioned for accentuating the international interest in this area of research.

  6. Processed Thematic Mapper Satellite Imagery for Selected Areas within the U.S.-Mexico Borderlands

    USGS Publications Warehouse

    Dohrenwend, John C.; Gray, Floyd; Miller, Robert J.

    2000-01-01

    The study is summarized in the Adobe Acrobat Portable Document Format (PDF) file OF00-309.PDF. This publication also contain satellite full-scene images of selected areas along the U.S.-Mexico border. These images are presented as high-resolution images in jpeg format (IMAGES). The folder LOCATIONS in contains TIFF images showing exact positions of easily-identified reference locations for each of the Landsat TM scenes located at least partly within the U.S. A reference location table (BDRLOCS.DOC in MS Word format) lists the latitude and longitude of each reference location with a nominal precision of 0.001 minute of arc

  7. Three-dimensional portable document format: a simple way to present 3-dimensional data in an electronic publication.

    PubMed

    Danz, Jan C; Katsaros, Christos

    2011-08-01

    Three-dimensional (3D) models of teeth and soft and hard tissues are tessellated surfaces used for diagnosis, treatment planning, appliance fabrication, outcome evaluation, and research. In scientific publications or communications with colleagues, these 3D data are often reduced to 2-dimensional pictures or need special software for visualization. The portable document format (PDF) offers a simple way to interactively display 3D surface data without additional software other than a recent version of Adobe Reader (Adobe, San Jose, Calif). The purposes of this article were to give an example of how 3D data and their analyses can be interactively displayed in 3 dimensions in electronic publications, and to show how they can be exported from any software for diagnostic reports and communications among colleagues. PMID:21803267

  8. Daily Bladder Diary

    MedlinePlus

    ... bladder diary. If you have Adobe's® Acrobat® Reader Software , you might prefer looking at the Print PDF Version (80 KB) of the diary as the print quality will be much enhanced. Please select which page ...

  9. Extra Dimensions: 3D in PDF Documentation

    NASA Astrophysics Data System (ADS)

    Graf, Norman A.

    2012-12-01

    Experimental science is replete with multi-dimensional information which is often poorly represented by the two dimensions of presentation slides and print media. Past efforts to disseminate such information to a wider audience have failed for a number of reasons, including a lack of standards which are easy to implement and have broad support. Adobe's Portable Document Format (PDF) has in recent years become the de facto standard for secure, dependable electronic information exchange. It has done so by creating an open format, providing support for multiple platforms and being reliable and extensible. By providing support for the ECMA standard Universal 3D (U3D) and the ISO PRC file format in its free Adobe Reader software, Adobe has made it easy to distribute and interact with 3D content. Until recently, Adobe's Acrobat software was also capable of incorporating 3D content into PDF files from a variety of 3D file formats, including proprietary CAD formats. However, this functionality is no longer available in Acrobat X, having been spun off to a separate company. Incorporating 3D content now requires the additional purchase of a separate plug-in. In this talk we present alternatives based on open source libraries which allow the programmatic creation of 3D content in PDF format. While not providing the same level of access to CAD files as the commercial software, it does provide physicists with an alternative path to incorporate 3D content into PDF files from such disparate applications as detector geometries from Geant4, 3D data sets, mathematical surfaces or tesselated volumes.

  10. Energy map of southwestern Wyoming - Energy data archived, organized, integrated, and accessible

    USGS Publications Warehouse

    Biewick, Laura R.H.; Jones, Nicholas R.; Wilson, Anna B.

    2013-01-01

    The Wyoming Landscape Conservation Initiative (WLCI) focuses on conserving world-class wildlife resources while facilitating responsible energy development in southwestern Wyoming. To further advance the objectives of the WLCI long-term, science-based effort, a comprehensive inventory of energy resource and production data is being published in two parts. Energy maps, data, documentation and spatial data processing capabilities are available in geodatabase, published map file (pmf), ArcMap document (mxd), Adobe Acrobat PDF map, and other digital formats that can be downloaded at the USGS website.

  11. Protocol for the E-Area Low Level Waste Facility Disposal Limits Database

    SciTech Connect

    Swingle, R

    2006-01-31

    A database has been developed to contain the disposal limits for the E-Area Low Level Waste Facility (ELLWF). This database originates in the form of an EXCEL{copyright} workbook. The pertinent sheets are translated to PDF format using Adobe ACROBAT{copyright}. The PDF version of the database is accessible from the Solid Waste Division web page on SHRINE. In addition to containing the various disposal unit limits, the database also contains hyperlinks to the original references for all limits. It is anticipated that database will be revised each time there is an addition, deletion or revision of any of the ELLWF radionuclide disposal limits.

  12. Aerial Population Estimates of Wild Horses (Equus caballus) in the Adobe Town and Salt Wells Creek Herd Management Areas Using an Integrated Simultaneous Double-Count and Sightability Bias Correction Technique

    USGS Publications Warehouse

    Lubow, Bruce C.; Ransom, Jason I.

    2007-01-01

    An aerial survey technique combining simultaneous double-count and sightability bias correction methodologies was used to estimate the population of wild horses inhabiting Adobe Town and Salt Wells Creek Herd Management Areas, Wyoming. Based on 5 surveys over 4 years, we conclude that the technique produced estimates consistent with the known number of horses removed between surveys and an annual population growth rate of 16.2 percent per year. Therefore, evidence from this series of surveys supports the validity of this survey method. Our results also indicate that the ability of aerial observers to see horse groups is very strongly dependent on skill of the individual observer, size of the horse group, and vegetation cover. It is also more modestly dependent on the ruggedness of the terrain and the position of the sun relative to the observer. We further conclude that censuses, or uncorrected raw counts, are inadequate estimates of population size for this herd. Such uncorrected counts were all undercounts in our trials, and varied in magnitude from year to year and observer to observer. As of April 2007, we estimate that the population of the Adobe Town /Salt Wells Creek complex is 906 horses with a 95 percent confidence interval ranging from 857 to 981 horses.

  13. HAZPAC; an interactive map of Pacific Rim natural hazards, population, and infrastructure

    USGS Publications Warehouse

    Bemis, B.L.; Goss, H.V.; Yurkovich, E.S.; Perron, T.J.; Howell, D.G.

    2002-01-01

    This is an online version of a CD-ROM publication. The text files that describe using this publication make reference to software provided on the disc. For this online version the software can be downloaded for free from Adobe Systems and Environmental Systems Research Institute, Inc. (ESRI). Welcome to HAZPAC! HAZPAC is an interactive map about natural hazard risk in the Pacific Rim region. It is intended to communicate to a broad audience the ideas of 'Crowding the Rim,' which is an international, public-private partnership that fosters collaborative solutions for regional risks. HAZPAC, which stands for 'HAZards of the PACific,' uses Geographic Information System (GIS) technology to help people visualize the socioeconomic connections and shared hazard vulnerabilities among Pacific Rim countries, as well as to explore the general nature of risk. Please refer to the 'INTRODUCTION TO HAZPAC' section of the readme file below to determine which HAZPAC project will be right for you. Once you have decided which HAZPAC project is suitable for you, please refer to the 'GETTING STARTED' sections in the readme file for some basic information that will help you begin using HAZPAC. Also, we highly recommend that you follow the Tutorial exercises in the project-specific HAZPAC User Guides. The User Guides are PDF (Portable Document Format) files that must be read with Adobe Acrobat Reader (a free copy of Acrobat Reader is available using the link near the bottom of this page).

  14. Tira Sujanpur: An Adobe of Katoch Dynasty

    NASA Astrophysics Data System (ADS)

    Shree, Venu; Sharma, Puneet

    2015-06-01

    Image of any ancient settlement can be interpreted through a continuous study of its Historical and Architectural developments. The best way to map this image is to analyze and explore old monuments, palaces and religious places of that city. This work is an attempt to showcase the glorious era of Art and Architecture which flourished during Katoch dynasty in north Himalayan region of India during 18th century. Being one of the most known examples of Katoch Dynasty Tira Sujanpur has been documented in detail in this paper. This documentation covers the detail study of relationship between townscape and public places. Architecture style of Katoch Dynasty, Splendid along the cluster of the buildings, Temples and palaces has also been giving due consideration in the paper.

  15. A Web-based Quantum Mechanics Course for first Year Graduate Students in Physics

    NASA Astrophysics Data System (ADS)

    Breinig, M.

    1996-11-01

    All class materials for the 1996 graduate Quantum Mechanics course at the University of Tennessee are distributed over the Internet (http://electron4.phys.utk.edu). Complete class notes are available in PDF format. Homework problems and solutions are distributed in PDF format or as scanned notes. Students need Web access using a graphical browser with a PDF reader plug-in (Adobe Acrobat) installed. The news and mail clients must be able to display attachments, such as graphics files, inline. A class news group has been set up. Students use this news group to discus class material, homework problems, and anything else of interest among themselves. Numerical solutions are presented in the form of Java programs.

  16. Concept Formation.

    ERIC Educational Resources Information Center

    Vaidya, Narendera

    This document, published in India by the Regional College of Education, deals with 13 subjects: the tough context (thinking), definitions of concept, functions of concept, the process of concept formation, discriminant learning, mediation process, second signalling system, factors affecting concept formation, studies in concept formation, the…

  17. Formative Assessment

    ERIC Educational Resources Information Center

    Technology & Learning, 2005

    2005-01-01

    In today's climate of high-stakes testing and accountability, educators are challenged to continuously monitor student progress to ensure achievement. This article details how formative assessment helps educators meet this challenge and to ensure achievement. Formative assessment can influence learning and support achievement, allowing teachers…

  18. 78 FR 72851 - Proposed Priority-Promise Zones

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-04

    ... Secretary of Education (Secretary) published in the Federal Register (78 FR 63913) a notice of proposed.... Or by email: Jane.Hodgdon@ed.gov . If you use a telecommunications device for the deaf (TDD) or a...). To use PDF you must have Adobe Acrobat Reader, which is available free at the site. You may...

  19. 77 FR 48974 - Applications for New Awards; Comprehensive Centers Program (CFDA 84.283B); Correction

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-15

    ..., 2012, we published in the Federal Register (77 FR 33564) a notice inviting applications for new awards.... Telephone: (202) 205-9198 or by email: fran.walter@ed.gov . If you use a telecommunications device for the... Adobe Acrobat Reader, which is available free at the site. You may also access documents of...

  20. 75 FR 28594 - Ready-to-Learn Television Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-21

    ... March 22, 2010, we published in the Federal Register (75 FR 13515) a notice inviting applications for...-mail: readytolearn@ed.gov . If you use a telecommunications device for the deaf, call the Federal Relay... PDF you must have Adobe Acrobat Reader, which is available free at this site. Note: The...

  1. 75 FR 25221 - Notice Extending the Deadline Date for Transmittal of Applications and the Deadline Date for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-07

    ..., we published in the Federal Register (75 FR 16446) a notice inviting applications for new awards for... telecommunications device for the deaf (TDD), call the Federal Relay Service (FRS), toll free, at 1-800-877-8339...: http://www.ed.gov/news/fedregister . To use PDF you must have Adobe Acrobat Reader, which is...

  2. 77 FR 4998 - List of Correspondence

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-01

    ... Topic Addressed: Surrogate Parents Letter dated September 6, 2011, to Board of Childcare, Community... System at: www.gpo.gov/fdsys . At this site you can view this document, as well as all other documents of... use PDF you must have Adobe Acrobat Reader, which is available free at the site. You may also...

  3. Use of the Webinar Tool (Elluminate) to Support Training: The Effects of Webinar-Learning Implementation from Student-Trainers' Perspective

    ERIC Educational Resources Information Center

    Wang, Shiang-Kwei; Hsu, Hui-Yin

    2008-01-01

    Recently, webinar (web seminar) tools (e.g., Elluminate, Adobe Acrobat Connect, Live Meeting) have been attracting more and more attention with the advancement of online learning technologies because webinar tools facilitate real-time communication and enrich the interactivity in an online learning environment. Corporations have long adopted…

  4. Concepts & Procedures. [SITE 2001 Section].

    ERIC Educational Resources Information Center

    Bauder, Deborah Y., Ed.; Mullick, Rosemary, Ed.; Sarner, Ronald, Ed.

    This document contains the following papers on concepts and procedures from the SITE (Society for Information Technology & Teacher Education) 2001 conference: "Using School District Standards To Develop Thematic Lessons for Electronic Portfolios" (Cindy L. Anderson and others); "Using Adobe Acrobat for Electronic Portfolio Development" (Helen C.…

  5. 3D PDF - a means of public access to geological 3D - objects, using the example of GTA3D

    NASA Astrophysics Data System (ADS)

    Slaby, Mark-Fabian; Reimann, Rüdiger

    2013-04-01

    In geology, 3D modeling has become very important. In the past, two-dimensional data such as isolines, drilling profiles, or cross-sections based on those, were used to illustrate the subsurface geology, whereas now, we can create complex digital 3D models. These models are produced with special software, such as GOCAD ®. The models can be viewed, only through the software used to create them, or through viewers available for free. The platform-independent PDF (Portable Document Format), enforced by Adobe, has found a wide distribution. This format has constantly evolved over time. Meanwhile, it is possible to display CAD data in an Adobe 3D PDF file with the free Adobe Reader (version 7). In a 3D PDF, a 3D model is freely rotatable and can be assembled from a plurality of objects, which can thus be viewed from all directions on their own. In addition, it is possible to create moveable cross-sections (profiles), and to assign transparency to the objects. Based on industry-standard CAD software, 3D PDFs can be generated from a large number of formats, or even be exported directly from this software. In geoinformatics, different approaches to creating 3D PDFs exist. The intent of the Authority for Mining, Energy and Geology to allow free access to the models of the Geotectonic Atlas (GTA3D), could not be realized with standard software solutions. A specially designed code converts the 3D objects to VRML (Virtual Reality Modeling Language). VRML is one of the few formats that allow using image files (maps) as textures, and to represent colors and shapes correctly. The files were merged in Acrobat X Pro, and a 3D PDF was generated subsequently. A topographic map, a display of geographic directions and horizontal and vertical scales help to facilitate the use.

  6. PDF Lecture Materials for Online and ``Flipped'' Format Astronomy Courses

    NASA Astrophysics Data System (ADS)

    Kary, D. M.; Eisberg, J.

    2013-04-01

    Online astronomy courses typically rely on students reading the textbook and/or a set of text-based lecture notes to replace the “lecture” material. However, many of our students report that this is much less engaging than in-person lectures, especially given the amount of interactive work such as “think-pair-share” problems done in many astronomy classes. Students have similarly criticized direct lecture-capture. To address this, we have developed a set of PowerPoint-style presentations with embedded lecture audio combined with prompts for student interaction including think-pair-share questions. These are formatted PDF packages that can be used on a range of different computers using free software. The presentations are first developed using Microsoft PowerPoint software. Audio recordings of scripted lectures are then synchronized with the presentations and the entire package is converted to PDF using Adobe Presenter. This approach combines the ease of editing that PowerPoint provides along with the platform-independence of PDF. It's easy to add, remove, or edit individual slides as needed, and PowerPoint supports internal links so that think-pair-share questions can be inserted with links to feedback based on the answers selected. Modern PDF files support animated visuals with synchronized audio and they can be read using widely available free software. Using these files students in an online course can get many of the benefits of seeing and hearing the course material presented in an in-person lecture format. Students needing extra help in traditional lecture classes can use these presentations to help review the materials covered in lecture. Finally, the presentations can be used in a “flipped” format in which students work through the presentations outside of class time while spending the “lecture” time on in-class interaction.

  7. Galaxy formation

    SciTech Connect

    Silk, J.

    1984-11-01

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

  8. Comet formation

    NASA Astrophysics Data System (ADS)

    Blum, J.

    2014-07-01

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

  9. The table of isotopes-8th edition and beyond

    SciTech Connect

    Firestone, R.B.

    1996-12-31

    A new edition of the Table of Isotopes has been published this year by John Wiley and Sons, Inc. This edition is the eighth in a series started by Glenn T. Seaborg in 1940. The two-volume, 3168-page, cloth-bound edition is twice the size of the previous edition published in 1978. It contains nuclear structure and decay data, based mainly on the Evaluated Nuclear Structure Data File (ENSDF), for >3100 isotopes and isomers. Approximately 24000 references are cited, and the appendices have been updated and extended. The book is packaged with an interactive CD-ROM that contains the Table of Isotopes in Adobe Acrobat Portable Document Format for convenient viewing on personal computer (PC) and UNIX workstations. The CD-ROM version contains a chart of the nuclides graphical index and separate indices organized for radioisotope users and nuclear structure physicists. More than 100000 hypertext links are provided to move the user quickly through related information free from the limitations of page size. Complete references with keyword abstracts are provided. The CD-ROM also contains the Table of Super-deformed Nuclear Bands and Fission Isomers; Tables of Atoms, Atomic Nuclei, and Subatomic Particles by Ivan P. Selinov; the ENSDF and nuclear structure reference (NSR) databases; the ENSDF manual by Jagdish K. Tuli; and Abode Acrobat Reader software.

  10. Planet Formation

    NASA Astrophysics Data System (ADS)

    Klahr, Hubert; Brandner, Wolfgang

    2011-02-01

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

  11. Orbital acrobatics in the Sun-Earth-Moon system

    NASA Technical Reports Server (NTRS)

    Farquhar, Robert W.; Dunham, D. W.; Hsu, S. C.

    1986-01-01

    Unconventional trajectory techniques for space missions in the Sun-Earth-Moon system, including libration-point orbits, gravity-assist maneuvers, and Earth-return trajectories are reviewed. The ISEE-3/ICE flight experience is used to illustrate the utility of libration-point orbits called halo-orbits. Five lunar gravity-assist maneuvers used by the ISEE-3/ICE spacecraft are discussed. The final lunar swingby sent the spacecraft into a heliocentric trajectory that will eventually intercept Comet Giacobini-Zinner. As an example of the Earth-return trajectory concept, a proposed mission that includes flybys of three comets and two asteroids is described.

  12. Worldwide experiences of endoscopic submucosal dissection: Not just Eastern acrobatics

    PubMed Central

    Cho, Kwang Bum; Jeon, Won Joong; Kim, Jae J

    2011-01-01

    The high incidence of gastric cancer has led to the initiation of cancer screening programs. As a result, the number of early gastric cancer cases has increased and consequentially, the cancer mortality rate has decreased. Moreover, the development of minimally invasive endoscopic treatment has been introduced for these early lesions. Endoscopic submucosal dissection (ESD) is now recognized as one of the preferred treatment modalities for premalignant gastrointestinal epithelial lesions and early gastric cancer without lymph node metastasis. We review the results of ESD including experiences in Japan and Korea, as well as western countries. PMID:21677828

  13. Formation testers

    SciTech Connect

    Brieger, E.

    1980-07-01

    A description is given of a method for use in obtaining multiple pressure tests of an earth formation traversed by a well bore by use of a sidewall fluid sampler well tool which has a fluid pressure sampling chamber in the well tool in open fluid communication with a pad sealing means, comprising the steps of: for one selected level in a well bore, moving a pad sealing means on the well tool into engagement with the wall of a well bore and isolating a wall segment of the earth formation; after the pad sealing means engges the wall segment of the earth formation, generating a hydraulic pressure in the well tool and applying said hydraulic pressure to said fluid pressure sampling chamber for increasing the volume of said fluid pressure sampling chamber thereby to dray a fluid sample from the earth formation engaged by the pad sealing means into the fluid pressure sampling chamber, sensing the pressure of said fluid sample as it is drawn into the fluid pressure sampling chamber while the volume of the sampling chamber is being increased, relieving the hydraulic pressure in the well tool with respect to said fluid pressur sampling chamber for decreasing the volume of said fluid pressure sampling chamber thereby to contact the sampling chamber to dischrge the fluid sample through the pad sealing means; retracting the sealing pad means and, after retrction of sealing pad means from engagement from the wall of the well bore, moving the well tool to a second location at another level in the well bore and, at the second location, repeating the steps of the method performed at the one selected level for obtaining another fluid sample and pressure sensing at said second location.

  14. Development of a Rapid, Standardized Data Inventory for R2K Field Programs

    NASA Astrophysics Data System (ADS)

    Arko, R. A.; Chayes, D. N.; Carbotte, S. M.; Ryan, W. B.; Lehnert, K. A.; Shank, T. M.

    2003-12-01

    Effective data management for Ridge2000 requires the production of a complete data inventory for every field program in a timely and standardized way. We are developing a set of forms to document 1.) basic field program information (dates and locations, platform, science party, etc); 2.) an inventory of sensor systems, data types (marine geophysical, physical and chemical oceanographic, rock and sediment samples, and biological), and file formats; 3.) supplemental attachments (written reports, instrument diagrams, etc); and 4.) a basic navigation track. We regard this as the minimal set of metadata which should be produced immediately at the end of a field program, in order to publicize it in an online database and satisfy agency requirements. We have developed a prototype set of Portable Document Format (PDF) forms which can be completed during a cruise through a combination of manual and automated input. PDF is a stable and widely-used format, with software available as both a commercial product (Adobe Acrobat) and an open-source library (http://www.pdflib.org). Completing a PDF form requires only the Acrobat Reader software, which is freely available for every major computing platform. Acrobat offers extensive functionality to aid in data inventory, including the ability to verify content on-the-fly, import data from other files and forms, show controlled vocabularies as pop-up menus, export to XML format, and print a high-quality readable report. Prototype forms have been tested on a recent transit of the CGC Healy, and we plan to continue testing on other ships and soliciting community feedback over the next several months. We envision a long-term plan in which a master set of forms is deployed with every R2K field program, along with a copy of Acrobat Reader, on lightweight storage media such as USB keys. The completed forms will then be transmitted to the data management center, where they are ingested automatically and the information made available in the

  15. Amphiplex Formation

    NASA Astrophysics Data System (ADS)

    Petersen, Shannon; Laaser, Jennifer; Lodge, Timothy

    2015-03-01

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

  16. Embedding and Publishing Interactive, 3-Dimensional, Scientific Figures in Portable Document Format (PDF) Files

    PubMed Central

    Barnes, David G.; Vidiassov, Michail; Ruthensteiner, Bernhard; Fluke, Christopher J.; Quayle, Michelle R.; McHenry, Colin R.

    2013-01-01

    With the latest release of the S2PLOT graphics library, embedding interactive, 3-dimensional (3-d) scientific figures in Adobe Portable Document Format (PDF) files is simple, and can be accomplished without commercial software. In this paper, we motivate the need for embedding 3-d figures in scholarly articles. We explain how 3-d figures can be created using the S2PLOT graphics library, exported to Product Representation Compact (PRC) format, and included as fully interactive, 3-d figures in PDF files using the movie15 LaTeX package. We present new examples of 3-d PDF figures, explain how they have been made, validate them, and comment on their advantages over traditional, static 2-dimensional (2-d) figures. With the judicious use of 3-d rather than 2-d figures, scientists can now publish, share and archive more useful, flexible and faithful representations of their study outcomes. The article you are reading does not have embedded 3-d figures. The full paper, with embedded 3-d figures, is recommended and is available as a supplementary download from PLoS ONE (File S2). PMID:24086243

  17. Habit formation.

    PubMed

    Smith, Kyle S; Graybiel, Ann M

    2016-03-01

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

  18. Habit formation

    PubMed Central

    Smith, Kyle S.; Graybiel, Ann M.

    2016-01-01

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

  19. Barrier Formation

    PubMed Central

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

    2014-01-01

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

  20. Pattern Formation

    NASA Astrophysics Data System (ADS)

    Hoyle, Rebecca

    2006-03-01

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

  1. Multimedia proceedings of the 10th Office Information Technology Conference

    SciTech Connect

    Hudson, B.

    1993-09-10

    The CD contains the handouts for all the speakers, demo software from Apple, Adobe, Microsoft, and Zylabs, and video movies of the keynote speakers. Adobe Acrobat is used to provide full-fidelity retrieval of the speakers` slides and Apple`s Quicktime for Macintosh and Windows is used for video playback. ZyIndex is included for Windows users to provide a full-text search engine for selected documents. There are separately labelled installation and operating instructions for Macintosh and Windows users and some general materials common to both sets of users.

  2. Star formation - An overview

    NASA Technical Reports Server (NTRS)

    Evans, N. J., II

    1985-01-01

    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.

  3. Formate Formation and Formate Conversion in Biological Fuels Production

    PubMed Central

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

    2011-01-01

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

  4. Structure Formation in Astrophysics

    NASA Astrophysics Data System (ADS)

    Chabrier, Gilles

    2009-01-01

    Part I. Physical Processes and Numerical Methods Common to Structure Formations in Astrophysics: 1. The physics of turbulence E. Levêque; 2. The numerical simulation of turbulence W. Schmidt; 3. Numerical methods for radiation magnetohydrodynamics in astrophysics R. Klein and J. Stone; 4. The role of jets in the formation of planets, stars, and galaxies R. Banerjee, R. Pudritz and R. Ouyed; 5. Advanced numerical methods in astrophysical fluid dynamics A. Hujeirat and F. Heitsch; Part II. Structure and Star Formation in the Primordial Universe: 6. New frontiers in cosmology and galaxy formation challenges for the future R. Ellis and J. Silk; 7. Galaxy formation physics T. Abel, G. Bryan and R. Teyssier; 8. First stars formation, evolution, feedback effects V. Bromm, A. Ferrara and A. Heger; Part III. Contemporary Star and Brown Dwarf Formation: a) Cloud Formation and Fragmentation: 9. Diffuse interstellar medium and the formation of molecular clouds P. Hennebelle, M. Mac Low and E. Vazquez-Semadeni; 10. The formation of distributed and clustered stars in molecular clouds T. Megeath, Z. -Y. Li and A. Nordlund; b) Core Fragmentation and Star Formation: 11. The formation and evolution of prestellar cores P. André, S. Basu and S. Inutsuka; 12. Models for the formation of massive stars; Part IV. Protoplanetary Disks and Planet Formation M. Krumholz and I. Bonnell: 13. Observational properties of disks and young stellar objects G. Duchêne, F. Ménard, J. Muzzerolle and S. Mohanty; 14. Structure and dynamics of protoplanetary disks C. Dullemond, R. Durisen and J. Papaloizou; 15. Planet formation and evolution theory and observation Y. Alibert, I. Baraffe, W. Benz, G. Laughlin and S. Udry; 16. Planet formation assembling the puzzle G. Wurm and T. Guillot; Part V. Summary: 17. Open issues in small- and large-scale structure formation R. Klessen and M. Mac Low; 18. Final word E. Salpeter.

  5. Structure Formation in Astrophysics

    NASA Astrophysics Data System (ADS)

    Chabrier, Gilles

    2011-02-01

    Part I. Physical Processes and Numerical Methods Common to Structure Formations in Astrophysics: 1. The physics of turbulence E. Levêque; 2. The numerical simulation of turbulence W. Schmidt; 3. Numerical methods for radiation magnetohydrodynamics in astrophysics R. Klein and J. Stone; 4. The role of jets in the formation of planets, stars, and galaxies R. Banerjee, R. Pudritz and R. Ouyed; 5. Advanced numerical methods in astrophysical fluid dynamics A. Hujeirat and F. Heitsch; Part II. Structure and Star Formation in the Primordial Universe: 6. New frontiers in cosmology and galaxy formation challenges for the future R. Ellis and J. Silk; 7. Galaxy formation physics T. Abel, G. Bryan and R. Teyssier; 8. First stars formation, evolution, feedback effects V. Bromm, A. Ferrara and A. Heger; Part III. Contemporary Star and Brown Dwarf Formation: a) Cloud Formation and Fragmentation: 9. Diffuse interstellar medium and the formation of molecular clouds P. Hennebelle, M. Mac Low and E. Vazquez-Semadeni; 10. The formation of distributed and clustered stars in molecular clouds T. Megeath, Z. -Y. Li and A. Nordlund; b) Core Fragmentation and Star Formation: 11. The formation and evolution of prestellar cores P. André, S. Basu and S. Inutsuka; 12. Models for the formation of massive stars; Part IV. Protoplanetary Disks and Planet Formation M. Krumholz and I. Bonnell: 13. Observational properties of disks and young stellar objects G. Duchêne, F. Ménard, J. Muzzerolle and S. Mohanty; 14. Structure and dynamics of protoplanetary disks C. Dullemond, R. Durisen and J. Papaloizou; 15. Planet formation and evolution theory and observation Y. Alibert, I. Baraffe, W. Benz, G. Laughlin and S. Udry; 16. Planet formation assembling the puzzle G. Wurm and T. Guillot; Part V. Summary: 17. Open issues in small- and large-scale structure formation R. Klessen and M. Mac Low; 18. Final word E. Salpeter.

  6. Star Formation in Galaxies

    NASA Technical Reports Server (NTRS)

    1987-01-01

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

  7. The Format Dilemma.

    ERIC Educational Resources Information Center

    Oder, Norman

    2002-01-01

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

  8. Possible costs associated with investigating and mitigating geologic hazards in rural areas of western San Mateo County, California with a section on using the USGS website to determine the cost of developing property for residences in rural parts of San Mateo County, California

    USGS Publications Warehouse

    Brabb, Earl E.; Roberts, Sebastian; Cotton, William R.; Kropp, Alan L.; Wright, Robert H.; Zinn, Erik N.; Digital database by Roberts, Sebastian; Mills, Suzanne K.; Barnes, Jason B.; Marsolek, Joanna E.

    2000-01-01

    This publication consists of a digital map database on a geohazards web site, http://kaibab.wr.usgs.gov/geohazweb/intro.htm, this text, and 43 digital map images available for downloading at this site. The report is stored as several digital files, in ARC export (uncompressed) format for the database, and Postscript and PDF formats for the map images. Several of the source data layers for the images have already been released in other publications by the USGS and are available for downloading on the Internet. These source layers are not included in this digital database, but rather a reference is given for the web site where the data can be found in digital format. The exported ARC coverages and grids lie in UTM zone 10 projection. The pamphlet, which only describes the content and character of the digital map database, is included as Postscript, PDF, and ASCII text files and is also available on paper as USGS Open-File Report 00-127. The full versatility of the spatial database is realized by importing the ARC export files into ARC/INFO or an equivalent GIS. Other GIS packages, including MapInfo and ARCVIEW, can also use the ARC export files. The Postscript map image can be used for viewing or plotting in computer systems with sufficient capacity, and the considerably smaller PDF image files can be viewed or plotted in full or in part from Adobe ACROBAT software running on Macintosh, PC, or UNIX platforms.

  9. Simple Ontology Format (SOFT)

    SciTech Connect

    Sorokine, Alexandre

    2011-10-01

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

  10. Medical image file formats.

    PubMed

    Larobina, Michele; Murino, Loredana

    2014-04-01

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

  11. Star Formation for Predictive Primordial Galaxy Formation

    NASA Astrophysics Data System (ADS)

    Milosavljević, Miloš; Safranek-Shrader, Chalence

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

  12. Tropical cyclone formation

    SciTech Connect

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

    1993-01-15

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

  13. Online multimedia teaching tool for Parkinson's disease.

    PubMed

    Misiaszek, Greg; Riconscente, Michelle; Henke, Maria; Walsh, John P

    2008-01-01

    We developed an online multimedia tool designed to enhance the student-learning environment in neurosciences through multi-sensory engagement. The combined use of scrolling text, narrations, and visual imagery engages multiple sensory modalities for effective learning, and it assists students in visualizing complex processes in the nervous system. The initial rollout of the online tool is for instruction in Parkinson's disease (PD), but its structure is flexible and can be used for teaching a variety of subjects. The instructor can access the tool online during lecture, and students can access the same information via the internet outside of class. In addition, each chapter is stand-alone and thus can be accessed online by other faculty or students to supplement other courses. Within each chapter or module, information is presented in outline format with greater detail accessible via sequential drop-down menus. This layering of related topics creates a spatial and motor-accessed path for learning. These multiple forms of engagement offer rich information representations to improve students' knowledge encoding, storing, and retrieval via multiple pathways. For instance, the tool includes student-controlled 2-D and 3-D animations, and video clip demonstrations of both patient case studies and on-campus research projects directly related to the subject material. Supplemental readings consist of current research articles (in Adobe Acrobat PDF file format) accessed within each educational topic. The teaching tool for PD is online at http://geroauen.usc.edu/Gero414_Beta/. PMID:23493487

  14. Disks and Outflows Around Young Stars

    NASA Astrophysics Data System (ADS)

    Beckwith, Steven; Staude, Jakob; Quetz, Axel; Natta, Antonella

    The subject of the book, the ubiquitous circumstellar disks around very young stars and the corresponding jets of outflowing matter, has recently become one of the hottest areas in astrophysics. The disks are thought to be precursors to planetary systems, and the outflows are thought to be a necessary phase in the formation of a young star, helping the star to get rid of angular momentum and energy as it makes its way onto the main sequence. The possible connections to planetary systems and stellar astrophysics makes these topics especially broad, appealing to generalists and specialists alike. The CD not only contains papers that could not be printed in the book but allows the authors to include a fair amount of data, often displayed as color images. The CD-ROM contains all the contributions printed in the corresponding book (Lecture Notes in Physics Vol. 465) and, in addition, those presented exclusively in digital form. Each contribution consists of a file in portable document format (PDF). The electronic version allows full-text searching within each file using Adobe's Acrobat Reader providing instructions for installation on Unix (Sun), PC and Macintosh computers, respectively. All contributions can be printed out; the color diagrams and color frames, which are printed in black and white in the book, can be viewed in color on screen.

  15. Geologic map of the Cucamonga Peak 7.5' quadrangle, San Bernardino County, California

    USGS Publications Warehouse

    Morton, D.M.; Matti, J.C.; Digital preparation by Koukladas, Catherine; Cossette, P.M.

    2001-01-01

    a. This Readme; includes in Appendix I, data contained in fif_met.txt b. The same graphic as plotted in 2 above. (Test plots have not produced 1:24,000-scale map sheets. Adobe Acrobat pagesize setting influences map scale.) The Correlation of Map Units and Description of Map Units is in the editorial format of USGS Miscellaneous Investigations Series (I-series) maps but has not been edited to comply with I-map standards. Within the geologic map data package, map units are identified by standard geologic map criteria such as formation-name, age, and lithology. Even though this is an author-prepared report, every attempt has been made to closely adhere to the stratigraphic nomenclature of the U. S. Geological Survey. Descriptions of units can be obtained by viewing or plotting the .pdf file (3b above) or plotting the postscript file (2 above). If roads in some areas, especially forest roads that parallel topographic contours, do not show well on plots of the geologic map, we recommend use of the USGS Cucamonga Peak 7.5’ topographic quadrangle in conjunction with the geologic map.

  16. Data format translation routines

    SciTech Connect

    Burris, R.D.

    1981-02-01

    To enable the effective connection of several dissimilar computers into a network, modification of the data being passed from one computer to another may become necessary. This document describes a package of routines which permit the translation of data in PDP-8 formats to PDP-11 or DECsystem-10 formats or from PDP-11 format to DECsystem-10 format. Additional routines are described which permit the effective use of the translation routines in the environment of the Fusion Energy Division (FED) network and the Elmo Bumpy Torus (EBT) data base.

  17. Simple Ontology Format (SOFT)

    2011-10-01

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

  18. GLOBAL STAR FORMATION REVISITED

    SciTech Connect

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

    2009-07-20

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

  19. Ice Formation on Wings

    NASA Technical Reports Server (NTRS)

    Ritz, L

    1939-01-01

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

  20. Formative Assessment Probes

    ERIC Educational Resources Information Center

    Eberle, Francis; Keeley, Page

    2008-01-01

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

  1. Formative Assessment in Context

    ERIC Educational Resources Information Center

    Oxenford-O'Brian, Julie

    2013-01-01

    This dissertation responds to critical gaps in current research on formative assessment practice which could limit successful implementation of this practice within the K-12 classroom context. The study applies a socio cultural perspective of learning to interpret a cross-case analysis of formative assessment practice occurring during one…

  2. School Formative Feedback Systems

    ERIC Educational Resources Information Center

    Halverson, Richard

    2010-01-01

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

  3. Sparse Image Format

    2007-04-12

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

  4. Sparse Image Format

    SciTech Connect

    Eads, Damian Ryan

    2007-04-12

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

  5. Teaching Letter Formation.

    ERIC Educational Resources Information Center

    Graham, Steve; Madan, Avi J.

    1981-01-01

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

  6. Circumstellar grain formation

    NASA Technical Reports Server (NTRS)

    Draine, B. T.

    1986-01-01

    Dust formation around cool giant and supergiant stars is examined in terms of grain formulation. Optical properties of small clusters, molecular physics of cluster nucleation and growth, circumstellar mass flows, and their application to alpha Ori are discussed.

  7. Display formats manual

    NASA Technical Reports Server (NTRS)

    Runnels, R. L.

    1973-01-01

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

  8. Plant Formate Dehydrogenase

    SciTech Connect

    John Markwell

    2005-01-10

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

  9. Autonomous Formation Flight

    NASA Technical Reports Server (NTRS)

    Schkolnik, Gerard S.; Cobleigh, Brent

    2004-01-01

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

  10. Computer simulation for prediction of performance and thermodynamic parameters of high energy materials.

    PubMed

    Muthurajan, H; Sivabalan, R; Talawar, M B; Asthana, S N

    2004-08-01

    A new code viz., Linear Output Thermodynamic User-friendly Software for Energetic Systems (LOTUSES) developed during this work predicts the theoretical performance parameters such as density, detonation factor, velocity of detonation, detonation pressure and thermodynamic properties such as heat of detonation, heat of explosion, volume of explosion gaseous products. The same code also assists in the prediction of possible explosive decomposition products after explosion and power index. The developed code has been validated by calculating the parameters of standard explosives such as TNT, PETN, RDX, and HMX. Theoretically predicated parameters are accurate to the order of +/-5% deviation. To the best of our knowledge, no such code is reported in literature which can predict a wide range of characteristics of known/unknown explosives with minimum input parameters. The code can be used to obtain thermochemical and performance parameters of high energy materials (HEMs) with reasonable accuracy. The code has been developed in Visual Basic having enhanced windows environment, and thereby advantages over the conventional codes, written in Fortran. The theoretically predicted HEMs performance can be directly printed as well as stored in text (.txt) or HTML (.htm) or Microsoft Word (.doc) or Adobe Acrobat (.pdf) format in the hard disk. The output can also be copied into the Random Access Memory as clipboard text which can be imported/pasted in other software as in the case of other codes. PMID:15225927

  11. High-speed network for delivery of education-on-demand

    NASA Astrophysics Data System (ADS)

    Cordero, Carlos; Harris, Dale; Hsieh, Jeff

    1996-03-01

    A project to investigate the feasibility of delivering on-demand distance education to the desktop, known as the Asynchronous Distance Education ProjecT (ADEPT), is presently being carried out. A set of Stanford engineering classes is digitized on PC, Macintosh, and UNIX platforms, and is made available on servers. Students on campus and in industry may then access class material on these servers via local and metropolitan area networks. Students can download class video and audio, encoded in QuickTimeTM and Show-Me TVTM formats, via file-transfer protocol or the World Wide Web. Alternatively, they may stream a vector-quantized version of the class directly from a server for real-time playback. Students may also download PostscriptTM and Adobe AcrobatTM versions of class notes. Off-campus students may connect to ADEPT servers via the internet, the Silicon Valley Test Track (SVTT), or the Bay-Area Gigabit Network (BAGNet). The SVTT and BAGNet are high-speed metropolitan-area networks, spanning the Bay Area, which provide IP access over asynchronous transfer mode (ATM). Student interaction is encouraged through news groups, electronic mailing lists, and an ADEPT home page. Issues related to having multiple platforms and interoperability are examined in this paper. The ramifications of providing a reliable service are discussed. System performance and the parameters that affect it are then described. Finally, future work on expanding ATM access, real-time delivery of classes, and enhanced student interaction is described.

  12. Energy map of southwestern Wyoming, Part A - Coal and wind

    USGS Publications Warehouse

    Biewick, Laura R.H.; Jones, Nicholas R.

    2012-01-01

    To further advance the objectives of the Wyoming Landscape Conservation Initiative (WLCI) the U.S. Geological Survey (USGS) and the Wyoming State Geological Survey (WSGS) have compiled Part A of the Energy Map of Southwestern Wyoming. Focusing primarily on electrical power sources, Part A of the energy map is a compilation of both published and previously unpublished coal (including coalbed gas) and wind energy resources data, presented in a Geographic Information System (GIS) data package. Energy maps, data, documentation and spatial data processing capabilities are available in a geodatabase, published map file (pmf), ArcMap document (mxd), Adobe Acrobat PDF map (plate 1) and other digital formats that can be downloaded at the USGS website. Accompanying the map (plate 1) and the geospatial data are four additional plates that describe the geology, energy resources, and related infrastructure. These tabular plates include coal mine (plate 2), coal field (plate 3), coalbed gas assessment unit (plate 4), and wind farm (plate 5) information with hyperlinks to source publications and data on the internet. The plates can be printed and examined in hardcopy, or accessed digitally. The data represent decades of research by the USGS, WSGS, BLM and others, and can facilitate landscape-level science assessments, and resource management decisionmaking.

  13. Using the World Wide Web for GIDEP Problem Data Processing at Marshall Space Flight Center

    NASA Technical Reports Server (NTRS)

    McPherson, John W.; Haraway, Sandra W.; Whirley, J. Don

    1999-01-01

    Since April 1997, Marshall Space Flight Center has been using electronic transfer and the web to support our processing of the Government-Industry Data Exchange Program (GIDEP) and NASA ALERT information. Specific aspects include: (1) Extraction of ASCII text information from GIDEP for loading into Word documents for e-mail to ALERT actionees; (2) Downloading of GIDEP form image formats in Adobe Acrobat (.pdf) for internal storage display on the MSFC ALERT web page; (3) Linkage of stored GRDEP problem forms with summary information for access from the MSFC ALERT Distribution Summary Chart or from an html table of released MSFC ALERTs (4) Archival of historic ALERTs for reference by GIDEP ID, MSFC ID, or MSFC release date; (5) On-line tracking of ALERT response status using a Microsoft Access database and the web (6) On-line response to ALERTs from MSFC actionees through interactive web forms. The technique, benefits, effort, coordination, and lessons learned for each aspect are covered herein.

  14. Lab Manual & Resources for Materials Science, Engineering and Technology on CD-Rom

    NASA Technical Reports Server (NTRS)

    Jacobs, James A.; McKenney, Alfred E.

    2001-01-01

    The National Educators' Workshop (NEW:Update) series of workshops has been in existence since 1986. These annual workshops focus on technical updates and laboratory experiments for materials science, engineering and technology, involving new and traditional content in the field. Scores of educators and industrial and national laboratory personnel have contributed many useful experiments and demonstrations which were then published as NASA Conference Proceedings. This "out poring of riches" creates an ever-expanding shelf of valuable teaching tools for college, university, community college and advanced high school instruction. Now, more than 400 experiments and demonstrations, representing the first thirteen years of NEW:Updates have been selected and published on a CD-ROM, through the collaboration of this national network of materials educators, engineers, and scientists. The CD-ROM examined in this document utilizes the popular Adobe Acrobat Reader format and operates on most popular computer platforms. This presentation provides an overview of the second edition of Experiments in Materials Science, Engineering and Technology (EMSET2) CD-ROM, ISBN 0-13-030534-0.

  15. Positronium Formation in Muscle

    PubMed Central

    Gustafson, D. R.

    1970-01-01

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

  16. Formation of the earth

    NASA Technical Reports Server (NTRS)

    Wetherill, George W.

    1990-01-01

    The origin of the earth is discussed in the context of the formation of the sun and the planets, and a standard model for such a formation assuming gravitational instability in a dense interstellar molecular cloud is outlined, along with the most significant variant of the model in which the loss of the nebular gas occurred after the formation of the earth. The formation of the sun and solar nebulae is addressed, and the coagulation of grains and the formation of small planetesimals are covered, along with the gravitational accumulation of planetesimals into planetary embryos and final stages of accumulation - embryos of planets. It is pointed out that the final stage of accumulation consists of the collision of these embryos; because of their large size, particularly after their further growth, these collisions represent giant impacts. It is concluded that the earth was initially an extremely hot and melted planet, surrounded by a fragile atmosphere and subject to violent impacts by bodies of the size of Ceres and even the moon.

  17. Molecules in star formation.

    NASA Astrophysics Data System (ADS)

    Shu, F. H.

    The author reviews current ideas and models in the problem of star formation from molecular cloud cores that are relatively isolated from the influences of other forming stars. He discusses the time scales, flow dynamics, and density and temperature structures applicable to each of the four stages of the entire process: (1) formation of a magnetized cloud core by ambipolar diffusion and evolution to a pivotal state of gravomagneto catastrophe; (2) self-similar collapse of the pivotal configuration and the formation of protostars, disks, and pseudo-disks; (3) onset of a magnetocentrifugally driven, lightly ionized wind from the interaction of an accretion disk and the magnetosphere of the central star, and the driving of bipolar molecular outflows; (4) evolution of pre-main-sequence stars surrounded by dusty accretion disks. For each of these stages and processes, he considers the characteristics of the molecular diagnostics needed to investigate the crucial aspects of the observational problem.

  18. Thrombus formation in vivo

    PubMed Central

    Furie, Bruce; Furie, Barbara C.

    2005-01-01

    To examine thrombus formation in a living mouse, new technologies involving intravital videomicroscopy have been applied to the analysis of vascular windows to directly visualize arterioles and venules. After vessel wall injury in the microcirculation, thrombus development can be imaged in real time. These systems have been used to explore the role of platelets, blood coagulation proteins, endothelium, and the vessel wall during thrombus formation. The study of biochemistry and cell biology in a living animal offers new understanding of physiology and pathology in complex biologic systems. PMID:16322780

  19. Crystal Formation in Inflammation.

    PubMed

    Franklin, Bernardo S; Mangan, Matthew S; Latz, Eicke

    2016-05-20

    The formation and accumulation of crystalline material in tissues is a hallmark of many metabolic and inflammatory conditions. The discovery that the phase transition of physiologically soluble substances to their crystalline forms can be detected by the immune system and activate innate immune pathways has revolutionized our understanding of how crystals cause inflammation. It is now appreciated that crystals are part of the pathogenesis of numerous diseases, including gout, silicosis, asbestosis, and atherosclerosis. In this review we discuss current knowledge of the complex mechanisms of crystal formation in diseased tissues and their interplay with the nutrients, metabolites, and immune cells that account for crystal-induced inflammation. PMID:26772211

  20. Gaussian entanglement of formation

    SciTech Connect

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

    2004-05-01

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

  1. Isolating Triggered Star Formation

    SciTech Connect

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

    2007-09-12

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

  2. BISAC Variable Format.

    ERIC Educational Resources Information Center

    Information Technology and Libraries, 1983

    1983-01-01

    Presents revision of Book Industry Systems Advisory Committee (BISAC) format designed specifically for electronic transmission of purchase orders for monograph or series titles combining fixed and variable length data fields which was approved in January 1983. Special characters, sample address descriptions, summary of fixed records, glossary, and…

  3. The Formation of Trihalomethanes.

    ERIC Educational Resources Information Center

    Trussell, R. Rhodes; Umphres, Mark D.

    1978-01-01

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

  4. Reconsidering Formative Measurement

    ERIC Educational Resources Information Center

    Howell, Roy D.; Breivik, Einar; Wilcox, James B.

    2007-01-01

    The relationship between observable responses and the latent constructs they are purported to measure has received considerable attention recently, with particular focus on what has become known as formative measurement. This alternative to reflective measurement in the area of theory-testing research is examined in the context of the potential…

  5. Formation of Freirian Facilitators.

    ERIC Educational Resources Information Center

    Noble, Phyllis

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

  6. Formation of planetesimals

    NASA Technical Reports Server (NTRS)

    Weidenschilling, Stuart J.

    1991-01-01

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

  7. Technobabble: File Formats.

    ERIC Educational Resources Information Center

    Wilson, Bradley

    1999-01-01

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

  8. 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...

  9. Common file formats.

    PubMed

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

    2007-01-01

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

  10. Bacterial formate hydrogenlyase complex

    PubMed Central

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

    2014-01-01

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

  11. Kepler Planet Formation

    NASA Technical Reports Server (NTRS)

    Lissauer, Jack J.

    2015-01-01

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

  12. 500+ Writing Formats.

    ERIC Educational Resources Information Center

    McIntosh, Margaret E.

    1997-01-01

    Suggests a multitude of ideas for students to communicate their ideas in writing using the language of mathematics. Includes a sampling of 500+ writing formats, 67 abbreviated writing assignments, and three complete assignments along with a sample student response to each. Sample assignments include advice column, biographical sketch, commercial,…

  13. Formation in the Classroom

    ERIC Educational Resources Information Center

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

    2011-01-01

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

  14. Insights on galaxy formation

    NASA Astrophysics Data System (ADS)

    Bullock, James Steven

    1999-12-01

    Recent advances in theoretical modeling coupled with a wealth of new observational data, provide a unique opportunity for gaining insight into process of galaxy formation. I present results which test and develop current theories. The analysis utilizes state of the art theoretical modeling and makes predictions aimed at comparisons with some of the latest and upcoming observational data sets. In part I, I discuss an analysis of the structure and properties of dark matter halos (believed to govern the dynamical evolution of galaxies). The results make use of very high-resolution N-body simulations, and are derived from a new hierarchical halo finder, designed especially for these projects and to complement advancements in simulation technology. I present information on the dark matter halo substructure, density profiles, angular momentum structure, and collision rates. In part II, I discuss some aspects of galaxy formation theory in light of new observational data. The discussion includes an investigation of the nature of high-redshift galaxies, the local velocity function of galaxies, and the use of gamma ray telescopes to probe the extra-galactic background light-the latter analysis is done in the context of semi-analytic modeling of galaxy formation. The most important conclusions of this thesis are as follows. (1)Dark matter halos at high redshift are much less concentrated than previously believed. implying that quiescently star-forming galaxies at high redshift are larger and dimmer than expected. (2)The observed bright. abundant. and highly clustered high- redshift (Lyman-break) galaxies are likely starbursts driven by collisions between relatively small galaxies at z ~ 3. And (3)there is a real possibility of using the growing advances in γ-ray astronomy to probe many poorly constrained processes of galaxy formation, including the stellar initial mass function and the star formation history of the universe.

  15. Pattern formation today

    PubMed Central

    Chuong, Cheng-Ming; Richardson, Michael K.

    2010-01-01

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

  16. Medusae Fossae Formation

    NASA Technical Reports Server (NTRS)

    2002-01-01

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

  17. Format( )MEDIC( )Input

    NASA Astrophysics Data System (ADS)

    Foster, K.

    1994-09-01

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

  18. Pattern formation during vasculogenesis.

    PubMed

    Czirok, Andras; Little, Charles D

    2012-06-01

    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

  19. Cosmological structure formation

    NASA Technical Reports Server (NTRS)

    Schramm, David N.

    1991-01-01

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

  20. Emptiness Formation Probability

    NASA Astrophysics Data System (ADS)

    Crawford, Nicholas; Ng, Stephen; Starr, Shannon

    2016-08-01

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

  1. Formation of bacterial nanocells

    NASA Astrophysics Data System (ADS)

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

    1998-07-01

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

  2. Prominence Formation Processes

    NASA Astrophysics Data System (ADS)

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

    2005-01-01

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

  3. Format-Preserving Encryption

    NASA Astrophysics Data System (ADS)

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

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

  4. Formate-assisted pyrolysis

    SciTech Connect

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

    2015-03-17

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

  5. Hail Formation in Florida

    NASA Astrophysics Data System (ADS)

    Stanley, Matthew

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

  6. Galaxy Formation and Evolution

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

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

  7. Mesospheric cloud formations

    NASA Technical Reports Server (NTRS)

    Forbes, J. M.

    1980-01-01

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

  8. Formation of Bulges

    NASA Astrophysics Data System (ADS)

    Silk, Joseph; Bouwens, Rychard

    1999-07-01

    Bulges, often identified with the spheroidal component of a galaxy,have a complex pedigree. Massive bulges are generally red and old,but lower mass bulges have broader dispersions in color that may becorrelated with disk colors. This suggests different formationscenarios. I will review possible formation sequences for bulges,describe the various signatures that distinguish these scenarios, anddiscuss implications for the high redshift universe.

  9. Terrestrial planet formation

    PubMed Central

    Righter, K.; O’Brien, D. P.

    2011-01-01

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

  10. Tetrahedron Formation Control

    NASA Technical Reports Server (NTRS)

    Guzman, Jose J.

    2003-01-01

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

  11. Mars brine formation experiment

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

    Evaporites, particularly carbonates, nitrates, and sulfates, may be major sinks of volatiles scavenged from the martian atmosphere. Mars is thought to have once had a denser, warmer atmosphere that permitted the presence of liquid surface water. The conversion of atmospheric CO2 into carbonate is hypothesized to have degraded the martian climate to its present state of a generally subfreezing, desiccated desert. The rate for such a conversion under martian conditions is poorly known, so the time scale of climate degradation by this process cannot be easily evaluated. If some models are correct, carbonate formation may have been fast at geological time scales. The experiments of Booth and Kieffer also imply fast (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.

  12. Terrestrial planet formation.

    PubMed

    Righter, K; O'Brien, D P

    2011-11-29

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

  13. Model of kimberlite formation

    NASA Astrophysics Data System (ADS)

    Kostrovitsky, Sergey; Fiveyskaya, Lyudmila

    2013-04-01

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

  14. Carbon Monoxide Poisoning

    MedlinePlus

    ... Health (NCEH) Format: Select one PDF [237 KB] File Formats Help: How do I view different file formats (PDF, DOC, PPT, MPEG) on this site? Adobe PDF file Microsoft PowerPoint file Microsoft Word file Microsoft Excel ...

  15. Formation of giant planets

    NASA Astrophysics Data System (ADS)

    Magni, G.; Coradini, A.

    2003-04-01

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

  16. Liposome formation in microgravity

    NASA Astrophysics Data System (ADS)

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

    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.

  17. Multiple star formation

    NASA Astrophysics Data System (ADS)

    Kraus, Adam L.

    2010-11-01

    In this thesis, I present a study of the formation and evolution of stars, particularly multiple stellar systems. Binary stars provide a key constraint on star formation because any successful model should reproduce the mass-dependent frequency, distribution of separations, and distribution of mass ratios. I have pursued a number of surveys for different ranges of parameter space, all yielding one overarching conclusion: binary formation is fundamentally tied to mass. Solar-mass stars have a high primordial binary frequency (50%--75%) and a wide range of separations (extending to >10,000 AU), but as the system mass decreases, the frequency and separation distribution also decrease. For brown dwarfs, binaries are rare (~10%--15%) and have separations of <5 AU. Inside of this outer separation cutoff, the separation distribution appears to be log-flat for solar-mass stars, and perhaps for lower-mass systems. Solar-mass binary systems appear to have a flat mass ratio distribution, but for primary masses <0.3 Msun, the distribution becomes increasingly biased toward similar-mass companions. My results also constrain the binary formation timescale and the postformation evolutionary processes that sculpt binary populations. The dynamical interaction timescale in sparse associations like Taurus and Upper Sco is far longer than their ages, which suggests that those populations are dynamically pristine. However, binary systems in denser clusters undergo significant dynamical processing that strips outer binary companions; the difference in wide binary properties between my sample and the field is explained by the composite origin of the field population. I also have placed the individual components of young binary systems on the HR diagram in order to infer their coevality. In Taurus, binary systems are significantly more coeval (Δτ~0.5 Myr) than the association as a whole (Δτ~3--5 Myr). Finally, my survey of young very-low-mass stars and brown dwarfs found no planetary

  18. Modeling river delta formation.

    PubMed

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

    2007-10-23

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

  19. Modeling river delta formation

    PubMed Central

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

    2007-01-01

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

  20. Adiabatic Halo Formation

    SciTech Connect

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

    2005-06-08

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

  1. Select forelimb muscles have evolved superfast contractile speed to support acrobatic social displays.

    PubMed

    Fuxjager, Matthew J; Goller, Franz; Dirkse, Annika; Sanin, Gloria D; Garcia, Sarah

    2016-01-01

    Many species perform rapid limb movements as part of their elaborate courtship displays. However, because muscle performance is constrained by trade-offs between contraction speed and force, it is unclear how animals evolve the ability to produce both unusually fast appendage movement and limb force needed for locomotion. To address this issue, we compare the twitch speeds of forelimb muscles in a group of volant passerine birds, which produce different courtship displays. Our results show that the two taxa that perform exceptionally fast wing displays have evolved 'superfast' contractile kinetics in their main humeral retractor muscle. By contrast, the two muscles that generate the majority of aerodynamic force for flight show unmodified contractile kinetics. Altogether, these results suggest that muscle-specific adaptations in contractile speed allow certain birds to circumvent the intrinsic trade-off between muscular speed and force, and thereby use their forelimbs for both rapid gestural displays and powered locomotion. PMID:27067379

  2. 75 FR 26321 - Public Meeting on Future Policy and Rulemaking for Normal, Utility, Acrobatic, and Commuter...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-11

    ...The FAA Small Airplane Directorate is issuing this notice to advise the public of a meeting to discuss ideas for future policy and rulemaking for small airplanes. We are attempting to determine the adequacy of the current airworthiness standards thoughout a small airplane's service life while anticipating future requirements. The outcome could affect the next 20 years of small airplane design,......

  3. Acrobat ants go global--origin, evolution and systematics of the genus Crematogaster (Hymenoptera: Formicidae).

    PubMed

    Blaimer, Bonnie B

    2012-11-01

    This study unravels the evolution and biogeographic history of the globally distributed ant genus Crematogaster on the basis of a molecular phylogeny, reconstructed from five nuclear protein-coding genes and a total of 3384 bp of sequence data. A particular emphasis is placed on the evolutionary history of these ants in the Malagasy region. Bayesian and likelihood analyses performed on a dataset of 124 Crematogaster ingroup taxa lend strong support for three deeply diverging phylogenetic lineages within the genus: the Orthocrema clade, the Global Crematogaster clade and the Australo-Asian Crematogaster clade. The 15 previous subgenera within Crematogaster are mostly not monophyletic. Divergence dating analyses and ancestral range reconstructions suggest that Crematogaster evolved in South-East Asia in the mid-Eocene (40-45 ma). The three major lineages also originated in this region in the late Oligocene/early Miocene (~24-30 ma). A first dispersal out of S-E Asia by an Orthocrema lineage is supported for 22-30 ma to the Afrotropical region. Successive dispersal events out of S-E Asia began in the early, and continued throughout the late Miocene. The global distribution of Crematogaster was achieved by subsequent colonizations of all major biogeographic regions by the Orthocrema and the Global Crematogaster clade. Molecular dating estimates and ancestral range evolution are discussed in the light of palaeogeographic changes in the S-E Asian region and an evolving ocean circulation system throughout the Eocene, Oligocene and Miocene. Eight dispersal events to/from Madagascar by Crematogaster are supported, with most events occurring in the late Miocene to Pliocene (5.0-9.5 ma). These results suggest that Crematogaster ants possess exceptional dispersal and colonization abilities, and emphasize the need for detailed investigations of traits that have contributed to the global evolutionary success of these ants. PMID:22796480

  4. Adaptive evolution of a derived radius morphology in manakins (Aves, Pipridae) to support acrobatic display behavior.

    PubMed

    Friscia, Anthony; Sanin, Gloria D; Lindsay, Willow R; Day, Lainy B; Schlinger, Barney A; Tan, Josh; Fuxjager, Matthew J

    2016-06-01

    The morphology of the avian skeleton is often studied in the context of adaptations for powered flight. The effects of other evolutionary forces, such as sexual selection, on avian skeletal design are unclear, even though birds produce diverse behaviors that undoubtedly require a variety of osteological modifications. Here, we investigate this issue in a family of passerine birds called manakins (Pipridae), which have evolved physically unusual and elaborate courtship displays. We report that, in species within the genus Manacus, the shaft of the radius is heavily flattened and shows substantial solidification. Past work anecdotally notes this morphology and attributes it to the species' ability to hit their wings together above their heads to produce loud mechanical sonations. Our results show that this feature is unique to Manacus compared to the other species in our study, including a variety of taxa that produce other sonations through alternate wing mechanisms. At the same time, our data reveal striking similarities across species in total radius volume and solidification. Together, this suggests that supposedly adaptive alterations in radial morphology occur within a conserved framework of a set radius volume and solidness, which in turn is likely determined by natural selection. Further allometric analyses imply that the radius is less constrained by body size and the structural demands that underlie powered flight, compared to other forelimb bones that are mostly unmodified across taxa. These results are consistent with the idea that the radius is more susceptible to selective modification by sexual selection. Overall, this study provides some of the first insight into the osteological evolution of passerine birds, as well as the way in which opposing selective forces can shape skeletal design in these species. J. Morphol. 277:766-775, 2016. © 2016 Wiley Periodicals, Inc. PMID:27027525

  5. Select forelimb muscles have evolved superfast contractile speed to support acrobatic social displays

    PubMed Central

    Fuxjager, Matthew J; Goller, Franz; Dirkse, Annika; Sanin, Gloria D; Garcia, Sarah

    2016-01-01

    Many species perform rapid limb movements as part of their elaborate courtship displays. However, because muscle performance is constrained by trade-offs between contraction speed and force, it is unclear how animals evolve the ability to produce both unusually fast appendage movement and limb force needed for locomotion. To address this issue, we compare the twitch speeds of forelimb muscles in a group of volant passerine birds, which produce different courtship displays. Our results show that the two taxa that perform exceptionally fast wing displays have evolved 'superfast' contractile kinetics in their main humeral retractor muscle. By contrast, the two muscles that generate the majority of aerodynamic force for flight show unmodified contractile kinetics. Altogether, these results suggest that muscle-specific adaptations in contractile speed allow certain birds to circumvent the intrinsic trade-off between muscular speed and force, and thereby use their forelimbs for both rapid gestural displays and powered locomotion. DOI: http://dx.doi.org/10.7554/eLife.13544.001 PMID:27067379

  6. Acrobats, Contortionists, and Cute Children: The Promise and Perversity of U.S. Women's Gymnastics.

    ERIC Educational Resources Information Center

    Chisholm, Ann

    2002-01-01

    Discusses how the media represents U.S. women's gymnastics, examining the degree to which the manifest promises of gymnastics (veneration of mass-mediated femininity and celebration of flexibility, strength, and agility) function in relation to economies of perversity. Suggests that the promises and perversities embodied by gymnasts are…

  7. Star Formation in Irregular Galaxies.

    ERIC Educational Resources Information Center

    Hunter, Deidre; Wolff, Sidney

    1985-01-01

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

  8. Formats for Presenting Procedural Instruction

    ERIC Educational Resources Information Center

    Blaiwes, Arthur S.

    1974-01-01

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

  9. Tooth formation - delayed or absent

    MedlinePlus

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

  10. Bubble formation in microgravity

    NASA Technical Reports Server (NTRS)

    Antar, Basil N.

    1994-01-01

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

  11. The Planet Formation Imager

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

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

  12. Fullerene formation and annealing

    SciTech Connect

    Mintmire, J.W.

    1996-04-05

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

  13. Biofilm formation by haloarchaea.

    PubMed

    Fröls, Sabrina; Dyall-Smith, Mike; Pfeifer, Felicitas

    2012-12-01

    A fluorescence-based live-cell adhesion assay was used to examine biofilm formation by 20 different haloarchaea, including species of Halobacterium, Haloferax and Halorubrum, as well as novel natural isolates from an Antarctic salt lake. Thirteen of the 20 tested strains significantly adhered (P-value  < 0.05) to a plastic surface. Examination of adherent cell layers on glass surfaces by differential interference contrast, fluorescence and confocal microscopy showed two types of biofilm structures. Carpet-like, multi-layered biofilms containing micro- and macrocolonies (up to 50 μm in height) were formed by strains of Halobacterium salinarum and the Antarctic isolate t-ADL strain DL24. The second type of biofilm, characterized by large aggregates of cells adhering to surfaces, was formed by Haloferax volcanii DSM 3757T and Halorubrum lacusprofundi DL28. Staining of the biofilms formed by the strongly adhesive haloarchaeal strains revealed the presence of extracellular polymers, such as eDNA and glycoconjugates, substances previously shown to stabilize bacterial biofilms. For Hbt. salinarum DSM 3754T and Hfx. volcanii DSM 3757T , cells adhered within 1 day of culture and remained viable for at least 2 months in mature biofilms. Adherent cells of Hbt. salinarum DSM 3754T showed several types of cellular appendages that could be involved in the initial attachment. Our results show that biofilm formation occurs in a surprisingly wide variety of haloarchaeal species. PMID:23057712

  14. STUDIES ON SHELL FORMATION

    PubMed Central

    Watabe, Norimitsu; Wilbur, Karl M.

    1961-01-01

    Details of crystal growth in the calcitostracum of Crassostrea virginica have been studied with the purpose of analyzing the formation of the overlapping rows of oriented tabular crystals characteristic of this part of the shell. Crystal elongation, orientation, and dendritic growth suggest the presence of strong concentration gradients in a thin layer of solution in which crystallization occurs. Formation of the overlapping rows can be explained by three processes observed in the shell: a two-dimensional tree-like dendritic growth in which one set of crystal branchings creeps over an adjacent set of branchings; three-dimensional dendritic growth; and growth by dislocation of crystal surfaces. Multilayers of crystals may thus be formed at one time. This is favored by infrequent secretion of a covering organic matrix which would inhibit crystal growth. The transitional zone covering the outer part of the calcitostracum and the inner part of the prismatic region is generally characterized by aggregates of small crystals with definite orientation. Growth in this zone appears to take place in a relatively homogeneous state of solution without strong concentration gradients. Thin membranes and bands of organic matrix were commonly observed in the transitional zone bordering the prismatic region. The membrane showed a very fine oriented network pattern. PMID:13783329

  15. Urbanization and Slum Formation

    PubMed Central

    Phua, Kai Hong

    2007-01-01

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

  16. Modeling of microstructure formation

    SciTech Connect

    Rappaz, M.; Gandin, C.A.; Jacot, A.; Charbon, C.

    1995-12-31

    As macroscopic models of solidification are now well advanced, the simulation of microstructure formation is becoming increasingly important. Tools based on Greens` functions (i.e., front-tracking) or diffuse interface methods (e.g., phase field) have been developed recently for the calculation of individual dendritic grains or of a few eutectic lamellae. Although very powerful and useful, such methods cannot be extended at present to the scale of a whole process mainly because of the very large computation time involved. At the intermediate mesoscopic scale of the grains, Monte Carlo (MC) or Cellular Automata (CA) methods can integrate nucleation and grain growth mechanisms in order to simulate the formation of grains during solidification. These latter methods have been coupled with Finite Element (FE) heat flow calculations in order to predict the grain structure at the scale of a whole process (computer metallography). The microstructural features which can be predicted using this coupled CA-FE model are: the morphology of the grains (columnar, equiaxed), the columnar-to-equiaxed transition, the selection of grains in the columnar zone, the crystallographic texture of the grains, the extension of grains in open regions of liquid, etc. Calculated parameters of the three-dimensional grain structure can also be related to the same entities obtained in metallographic cross sections (computer stereology).

  17. Method for measuring pollutant formation

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

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

  18. Formative Assessment: Simply, No Additives

    ERIC Educational Resources Information Center

    Roskos, Kathleen; Neuman, Susan B.

    2012-01-01

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

  19. LISA satellite formation control

    NASA Astrophysics Data System (ADS)

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

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

  20. Theories of galaxy formation

    SciTech Connect

    Jones, B.J.T.

    1980-01-01

    The current status of some theories of galaxy formation that are consistent with the hot big bang origin of the universe is reviewed. In the cosmic turbulence theory, an attempt is made to explain not only the characteristic masses and angular momenta of galaxies, but to describe in detail the spectrum of galaxy clustering problems with regard to the observed abundances of the light elements, a Kolmogorov spectrum of turbulence and the fireball are discussed. Attention is given to a primordial chaotic magnetic field, the comparison between baryon-symmetric cosmologies, the origin of galactic spin and theories starting from isothermal perturbations. Also considered are the dilemma of the initial conditions with respect to the era after 10 to the -4th s, and the pancake theory, in which the planar structures that arise provide a natural explanation for filamentary structures.

  1. Physics of amniote formation.

    PubMed

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

    2016-08-01

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

  2. Pattern Formation in Materials

    NASA Astrophysics Data System (ADS)

    Karma, Alain

    2011-04-01

    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.

  3. Dislocation Formation in Alloys

    NASA Astrophysics Data System (ADS)

    Minami, Akihiko; Onuki, Akira

    2006-05-01

    An interaction between dislocations and phase transitions is studied by a phase field model both in two and three dimensional systems. Our theory is a simple extension of the traditional linear elastic theory, and the elastic energy is a periodic function of local strains which is reflecting the periodicity of crystals. We find that the dislocations are spontaneously formed by quenching. Dislocations are formed from the interface of binary alloys, and slips are preferentially gliding into the soft metals. In three dimensional systems, formation of dislocations under applied strain is studied in two phase state. We find that the dislocation loops are created from the surface of hard metals. We also studied the phase separation above the coexisting temperature which is called as the Cottrell atmosphere. Clouds of metals cannot catch up with the motion of dislocations at highly strained state.

  4. Group Formation in Economics

    NASA Astrophysics Data System (ADS)

    Demange, Gabrielle; Wooders, Myrna

    2005-01-01

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

  5. Mechanism of GEMS formation

    SciTech Connect

    Bradley, J P; Dai, Z R

    2004-03-10

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

  6. Myxobacteria Fruiting Body Formation

    NASA Astrophysics Data System (ADS)

    Jiang, Yi

    2006-03-01

    Myxobacteria are social bacteria that swarm and glide on surfaces, and feed cooperatively. When starved, tens of thousands of cells change their movement pattern from outward spreading to inward concentration; they form aggregates that become fruiting bodies, inside which cells differentiate into nonmotile, environmentally resistant spores. Traditionally, cell aggregation has been considered to imply chemotaxis, a long-range cell interaction mediated by diffusing chemicals. However, myxobacteria aggregation is the consequence of direct cell-contact interactions. I will review our recent efforts in modeling the fruiting body formation of Myxobacteria, using lattice gas cellular automata models that are based on local cell-cell contact signaling. These models have reproduced the individual phases in Myxobacteria development such as the rippling, streaming, early aggregation and the final sporulation; the models can be unified to simulate the whole developmental process of Myxobacteria.

  7. DUST FORMATION IN MACRONOVAE

    SciTech Connect

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

    2014-07-01

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

  8. Glass formation in microgravity

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

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

  9. Recipes for planet formation

    NASA Astrophysics Data System (ADS)

    Meyer, Michael R.

    2009-11-01

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

  10. Streamer formation in sprites

    NASA Astrophysics Data System (ADS)

    McHarg, M. G.; Kammae, T.; Nielsen, H. C.

    2005-12-01

    Models of sprite formation for positive cloud-to-ground lightning strokes predict both downward (positive), and upward (negative) propagating streamers. Previous high speed camera observations of sprites are generally consistent with these predictions, but have been unable to resolve the temporal formation of the streamers due to frame rates limited to a few thousand frames per second. We report observations made during the evening of 9 July 2005 at 10,000 frames per second, with the image intensifier gated to 50 microseconds per frame. These observations often show the streamer head to be a bead-like structure propagating downward at approximately 7x106 m/s for 1,500 microseconds. The bead is followed by a dark region, and the main emissions from the sprite column are delayed ~800 microseconds after the passage of the streamer head. There are also "beads" which clearly propagate upward. Some events appear to be very similar to laboratory images of time resolved streamer zones. We interpret these observations in terms of positive/negative streamers. We see evidence for branching of the streamer tips in several cases, as well as evidence of upward propagating streamers transitioning into a more diffuse emission. Previous work (Pasko and Stenbaek-Nielsen, GRL 29(10), 2002) indicates this transition region has a lower border at an altitude when the dielectric relaxation time scale equals the time scale for an individual electron to develop into a streamer, and an upper border when the dielectric relaxation time scale roughly equals the dissociative attachment time scale. The present observations appear to be broadly consistent with this interpretation.

  11. Hazards to Planet Formation

    NASA Astrophysics Data System (ADS)

    Bally, J.

    2001-05-01

    The Orion Nebula provides a remarkable window on the first few million years in the lives of typical young stars and planetary systems. HST has demonstrated that most young stars in the Nebula are surrounded by circumstellar disks (the so-called `proplyds'). While these observations show that planet forming environments may be common, they also demonstrate that Orion's disks are being destroyed by intense UV radiation fields. `Gravel' sufficiently large to resist photo-erosion (meter scale solids or ices) may lock-up sufficient material to eventually build rocky planets. Indeed, there is evidence for large solids in some proplyds. But, the hydrogen and helium needed for the formation of giant planets will be removed. To form in Orion-like environments, giant planets must be assembled promptly prior to UV exposure. Even rocky planets may not form if the photoionized disk corona causes surviving large particles in the disk to spiral into the central star. Thus, nearby massive stars pose severe hazards to planet formation. Star counts indicate that most stars form in Orion-like environments. Only about 10% of young stars are born in shielded environments such as the Taurus or L1641 clouds where disks may escape photo-erosion. In dark clouds, the majority of stars (> 80%) form in non-hierarchal multiple star systems where close encounters with sibling stars can destroy disks and eject young planets. Thus, most stars may never develop planetary systems. These considerations indicate that extra-Solar planets may be rare, contrary to the popular view. These conclusions are consistent with the recent discoveries of extra-Solar planets around a few percent of single stars.

  12. Medusae Fossae Formation

    NASA Technical Reports Server (NTRS)

    2002-01-01

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

  13. Medusae Fossae Formation

    NASA Technical Reports Server (NTRS)

    2002-01-01

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

  14. 39 CFR 3001.10 - Form and number of copies of documents.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... service must be printed from a text-based pdf version of the document, where possible. Otherwise, they may... generated in either Acrobat (pdf), Word, or WordPerfect, or Rich Text Format (rtf)....

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

    PubMed

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

    2014-06-27

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

  16. Bubble formation in microgravity

    NASA Technical Reports Server (NTRS)

    Antar, Basil N.

    1996-01-01

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

  17. Nuclear ``pasta'' formation

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  18. Acromioclavicular joint cyst formation.

    PubMed

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

    2010-03-01

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

  19. Studies on Shell Formation

    PubMed Central

    Watabe, Norimitsu; Sharp, D. Gordon; Wilbur, Karl M.

    1958-01-01

    Electron microscope observations have been made by means of the replica method on growth processes of calcite crystals of the nacreous layer of the shell of the oyster, Crassostrea virginica. Layer formation is initiated by the secretion of a conchiolin matrix and the deposition of rounded crystal seeds on or in this material. In some areas crystal seeds are elongate and within a given area show a similar orientation, probably due to slower deposition. The seeds appear to increase in size by dendritic growth, and smaller seeds become incorporated into larger ones which come into contact to form a single layer. With further growth, crystals overlap, forming a step-like arrangement. The direction of growth is frequently different in neighboring regions. Crystal seeds deposited on crystal surfaces are usually elongate and oriented. Well developed crystals have a tabular idiomorphic form and are parallel in their growth. Rounded and irregular crystals were also observed. The crystals show reticular structure with units of the order of 100 A and striations corresponding with the rhombohedral axes of the crystals. The role of the mantle is discussed in relation to the growth patterns of crystals and shell structure. PMID:13549499

  20. Beach-cusp formation

    USGS Publications Warehouse

    Sallenger, A.H., Jr.

    1979-01-01

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

  1. Large Format Radiographic Imaging

    SciTech Connect

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

    1999-08-01

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

  2. The formation of dew

    NASA Astrophysics Data System (ADS)

    Beysens, D.

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

  3. Surficial geologic maps along the riparian zone of the Animas River and its headwater tributaries, Silverton to Durango, Colorado, with upper Animas River watershed gradient profiles

    USGS Publications Warehouse

    Blair, R.W.; Yager, D.B.; Church, S.E.

    2002-01-01

    This product consists of Adobe Acrobat .PDF format documents for 10 surficial geologic strip maps along the Animas River watershed from its major headwater tributaries, south to Durango, Colorado. The Animas River originates in the San Juan Mountains north of the historic mining town of Silverton, Colorado. The surficial geologic maps identify surficial deposits, such as flood-plain and terrace gravels, alluvial fans, glacial till, talus, colluvium, landslides, and bogs. Sixteen primary units were mapped that included human-related deposits and structures, eight alluvial, four colluvial, one glacial, travertine deposits, and undifferentiated bedrock. Each of the surficial geologic strip maps has .PDF links to surficial geology photographs, which enable the user to take a virtual tour of these deposits. Geochemical data collected from mapped surficial deposits that pre- and postdate mining activity have aided in determining the geochemical baseline in the watershed. Several photographs with their corresponding geochemical baseline profiles are accessible through .PDF links from several of the maps. A single coverage for all surficial deposits mapped is included as an ArcInfo shape file as an Arc Export format .e00 file. A gradient map for major headwater tributary streams to the Animas River is also included. The gradient map has stream segments that are color-coded based on relative variations in slope and .PDF format links to each stream gradient profile. Stream gradients were derived from U.S. Geological Survey 10-m digital elevation model data. This project was accomplished in support of the U.S. Geological Survey's Abandoned Mine Lands Initiative in the San Juan Mountains, Colorado.

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

    NASA Astrophysics Data System (ADS)

    Liebst, Kelley; Scowen, Paul A.

    2014-06-01

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

  5. Formation of Bidisperse Particle Clouds

    NASA Astrophysics Data System (ADS)

    Er, Jenn Wei; Zhao, Bing; Law, Adrian W. K.; Adams, E. Eric

    2014-11-01

    When a group of dense particles is released instantaneously into water, their motion has been conceptualized as a circulating particle thermal (Ruggerber 2000). However, Wen and Nacamuli (1996) observed the formation of particle clumps characterized by a narrow, fast moving core shedding particles into wakes. They observed the clump formation even for particles in the non-cohesive range as long as the source Rayleigh number was large (Ra > 1E3) or equivalently the source cloud number (Nc) was small (Nc < 3.2E2). This physical phenomenon has been investigated by Zhao et al. (2014) through physical experiments. They proposed the theoretical support for Nc dependence and categorized the formation processes into cloud formation, transitional regime and clump formation. Previous works focused mainly on the behavior of monodisperse particles. The present study further extends the experimental investigation to the formation process of bidisperse particles. Experiments are conducted in a glass tank with a water depth of 90 cm. Finite amounts of sediments with various weight proportions between coarser and finer particles are released from a cylindrical tube. The Nc being tested ranges from 6E-3 to 9.9E-2, which covers all the three formation regimes. The experimental results showed that the introduction of coarse particles promotes cloud formation and reduce the losses of finer particles into the wake. More quantitative descriptions of the effects of source conditions on the formation processes will be presented during the conference.

  6. Plasmapause formation at Saturn

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  7. The Tuscaloosa Formation revisited

    SciTech Connect

    Hansley, P.L.

    1996-09-01

    A petrologic study of the Upper Cretaceous lower Tuscaloosa Formation in the Gulf Coast from depths of 2,700 to 6,000 in indicates that anomalously high porosity (>20 percent) in deep gas and condensate-bearing sandstones (5,000 to 6,000 m) is approximately evenly divided between primary and secondary porosity. Primary porosity was preserved by early, iron-rich grain-rimming chlorite and quartz overgrowths. Most secondary porosity resulted from dissolution of carbonate cements. Moldic pores outlined by chlorite were created by dissolution of unstable feldspars and rock fragments. Interparticle clay microporosity is significant in sandstones containing authigenic kaolinite and (or) chlorite. Pores were filled in the deepest sandstones by quartz overgrowths and a late magnesium-rich chlorite that is commonly obscured by fibrous illite. Voids were created in the early Tertiary(?) by acidic meteoric waters and during deep burial by brines carrying organic and inorganic acids that were released during hydrocarbon maturation in neighboring shales. Oil fills dissolution voids in ankerite cement and albitized plagioclase and coats most authigenic minerals. Two-phase primary fluid inclusions in quartz overgrowths which also contain oil-bearing inclusions have homogenization temperatures between 125{degrees}C and 134{degrees}C. These temperatures combined with a burial history reconstruction indicate that hydrocarbons migrated into Tuscaloosa sandstones during the Miocene. Overpressuring began in the middle Tertiary along with gas generation in the Tuscaloosa. These events coincided with the end of deep meteoric flow through the Gulf section and the beginning of a compactional hydrologic regime. Precipitation of quartz overgrowths and hydrocarbons at this time locally created effective pressure seals.

  8. Planet formation and searches

    NASA Astrophysics Data System (ADS)

    Montgomery, Ryan Michael

    2009-08-01

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

  9. Medusae Fossae Formation

    NASA Technical Reports Server (NTRS)

    1998-01-01

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

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

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

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

    ERIC Educational Resources Information Center

    Keeley, Page

    2013-01-01

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

  11. The Formation of Galactic Bulges

    NASA Astrophysics Data System (ADS)

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

    2000-03-01

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

  12. The formation of Pangea

    NASA Astrophysics Data System (ADS)

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

    2013-05-01

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

  13. Fruit and Vegetable Consumption of U.S. Youth, 2009-2010

    MedlinePlus

    ... to Order from the National Technical Information Service File Formats Help: How do I view different file formats (PDF, DOC, PPT, MPEG) on this site? Adobe PDF file Microsoft PowerPoint file Microsoft Word file Microsoft Excel ...

  14. Patient Safety Threat - Syringe Reuse

    MedlinePlus

    ... Plan to Prevent HAIs HICPAC One & Only Campaign File Formats Help: How do I view different file formats (PDF, DOC, PPT, MPEG) on this site? Adobe PDF file Microsoft PowerPoint file Microsoft Word file Microsoft Excel ...

  15. Malaria and Travelers

    MedlinePlus

    ... a CDC Malaria Branch clinician. malaria@cdc.gov File Formats Help: How do I view different file formats (PDF, DOC, PPT, MPEG) on this site? Adobe PDF file Microsoft PowerPoint file Microsoft Word file Microsoft Excel ...

  16. Malaria Treatment (United States)

    MedlinePlus

    ... a CDC Malaria Branch clinician. malaria@cdc.gov File Formats Help: How do I view different file formats (PDF, DOC, PPT, MPEG) on this site? Adobe PDF file Microsoft PowerPoint file Microsoft Word file Microsoft Excel ...

  17. Choosing a Drug to Prevent Malaria

    MedlinePlus

    ... a CDC Malaria Branch clinician. malaria@cdc.gov File Formats Help: How do I view different file formats (PDF, DOC, PPT, MPEG) on this site? Adobe PDF file Microsoft PowerPoint file Microsoft Word file Microsoft Excel ...

  18. Malaria Facts

    MedlinePlus

    ... a CDC Malaria Branch clinician. malaria@cdc.gov File Formats Help: How do I view different file formats (PDF, DOC, PPT, MPEG) on this site? Adobe PDF file Microsoft PowerPoint file Microsoft Word file Microsoft Excel ...

  19. Mission Critical: Preventing Antibiotic Resistance

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  20. Antibiotic / Antimicrobial Resistance Glossary

    MedlinePlus

    ... on the Farm Get Smart About Antibiotics Week File Formats Help: How do I view different file formats (PDF, DOC, PPT, MPEG) on this site? Adobe PDF file Microsoft PowerPoint file Microsoft Word file Microsoft Excel ...

  1. Home Canning and Botulism

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  2. Antibiotic-Resistant Gonorrhea (ARG)

    MedlinePlus

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  3. Strategic National Stockpile (SNS)

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  4. Antibiotic and Antimicrobial Resistance: Threat Report 2013

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  5. Counterfeit and Substandard Antimalarial Drugs

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    ... a CDC Malaria Branch clinician. malaria@cdc.gov File Formats Help: How do I view different file formats (PDF, DOC, PPT, MPEG) on this site? Adobe PDF file Microsoft PowerPoint file Microsoft Word file Microsoft Excel ...

  6. Hepatitis Risk Assessment

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    ... About the Division of Viral Hepatitis Contact Us File Formats Help: How do I view different file formats (PDF, DOC, PPT, MPEG) on this site? Adobe PDF file Microsoft PowerPoint file Microsoft Word file Microsoft Excel ...

  7. Giardia & Pets

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    ... Vet Parasitol. 2011;187(1-2):93-8. File Formats Help: How do I view different file formats (PDF, DOC, PPT, MPEG) on this site? Adobe PDF file Microsoft PowerPoint file Microsoft Word file Microsoft Excel ...

  8. FastStats: Influenza

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  9. FastStats: Pneumonia

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  10. FastStats: Sinus Conditions

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  11. FastStats: Alcohol Use

    MedlinePlus

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  12. CDC Vital Signs: Child Injury

    MedlinePlus

    ... 1.1 MB] Read the MMWR Science Clips File Formats Help: How do I view different file formats (PDF, DOC, PPT, MPEG) on this site? Adobe PDF file Microsoft PowerPoint file Microsoft Word file Microsoft Excel ...

  13. FastStats: Birth Defects or Congenital Anomalies

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  14. FastStats: Mental Health

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  15. FastStats: Diabetes

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  16. FastStats: Health of American Indian or Alaska Native Population

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  17. FastStats: Obesity and Overweight

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  18. Viral Hemorrhagic Fevers

    MedlinePlus

    ... Related Links About VSPB (Viral Special Pathogens Branch) File Formats Help: How do I view different file formats (PDF, DOC, PPT, MPEG) on this site? Adobe PDF file Microsoft PowerPoint file Microsoft Word file Microsoft Excel ...

  19. CDC Vital Signs: Recipe for Food Safety

    MedlinePlus

    ... MMWR RSS VitalSigns RSS Error processing SSI file File Formats Help: How do I view different file formats (PDF, DOC, PPT, MPEG) on this site? Adobe PDF file Microsoft PowerPoint file Microsoft Word file Microsoft Excel ...

  20. FastStats: Self-Inflicted Injury/Suicide

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  1. FastStats: Cerebrovascular Disease or Stroke

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  2. Hip Fractures among Older Adults

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  3. Infection Control: The Use and Handling of Toothbrushes

    MedlinePlus

    ... Control in Dental Settings FAQs for Infection Control File Formats Help: How do I view different file formats (PDF, DOC, PPT, MPEG) on this site? Adobe PDF file Microsoft PowerPoint file Microsoft Word file Microsoft Excel ...

  4. Campylobacter

    MedlinePlus

    ... 2020 and Food Safety Food Safety Modernization Act File Formats Help: How do I view different file formats (PDF, DOC, PPT, MPEG) on this site? Adobe PDF file Microsoft PowerPoint file Microsoft Word file Microsoft Excel ...

  5. FastStats: Allergies/Hay Fever

    MedlinePlus

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  6. FastStats: Chronic Liver Disease and Cirrhosis

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  7. FastStats: Viral Hepatitis

    MedlinePlus

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  8. FastStats: Anemia or Iron Deficiency

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  9. FastStats: Whooping Cough or Pertussis

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  10. Measles -- Q&A about Disease & Vaccine

    MedlinePlus

    ... Autism Top of Page Related Page Measles Vaccination File Formats Help: How do I view different file formats (PDF, DOC, PPT, MPEG) on this site? Adobe PDF file Microsoft PowerPoint file Microsoft Word file Microsoft Excel ...

  11. FastStats: Inpatient Surgery

    MedlinePlus

    ... Disability Statistics Where to Write for Vital Records File Formats Help: How do I view different file formats (PDF, DOC, PPT, MPEG) on this site? Adobe PDF file Microsoft PowerPoint file Microsoft Word file Microsoft Excel ...

  12. FastStats: Illegal Drug Use

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  13. FastStats: Health of Hispanic or Latino Population

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  14. Cytomegalovirus (CMV) and Congenital CMV Infection: People Who Care for Infants and Children

    MedlinePlus

    ... of personal contact in the healthcare setting. To learn more about how CMV is spread, see Transmission . Top of ... Formats Help: How do I view different file formats (PDF, DOC, PPT, MPEG) on this site? Adobe PDF ...

  15. Dog Bites

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  16. FAQs about Baseline Testing among Young Athletes

    MedlinePlus

    ... HEADS UP & CDC's Injury Center HEADS UP Resources File Formats Help: How do I view different file formats (PDF, DOC, PPT, MPEG) on this site? Adobe PDF file Microsoft PowerPoint file Microsoft Word file Microsoft Excel ...

  17. National Institute for Occupational Safety and Health

    MedlinePlus

    ... States Division NIOSH Awards Search the NIOSH Website File Formats Help: How do I view different file formats (PDF, DOC, PPT, MPEG) on this site? Adobe PDF file Microsoft PowerPoint file Microsoft Word file Microsoft Excel ...

  18. National Center for Health Statistics

    MedlinePlus

    ... Facebook Twitter YouTube RSS Email Updates Mobile Apps File Formats Help: How do I view different file formats (PDF, DOC, PPT, MPEG) on this site? Adobe PDF file Microsoft PowerPoint file Microsoft Word file Microsoft Excel ...

  19. History of Bioterrorism: Botulism

    MedlinePlus

    ... Centers for Disease Control and Prevention (CDC), 1999. File Formats Help: How do I view different file formats (PDF, DOC, PPT, MPEG) on this site? Adobe PDF file Microsoft PowerPoint file Microsoft Word file Microsoft Excel ...

  20. FastStats: Hospice Care

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  1. FastStats: Kidney Disease

    MedlinePlus

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  2. FastStats: Sexually Transmitted Diseases/STD

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  3. Formation Algorithms and Simulation Testbed

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

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

  4. Formative Assessment: A Critical Review

    ERIC Educational Resources Information Center

    Bennett, Randy Elliot

    2011-01-01

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

  5. New Frontiers in Formative Assessment

    ERIC Educational Resources Information Center

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

    2011-01-01

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

  6. The Principal as Formative Coach

    ERIC Educational Resources Information Center

    Nidus, Gabrielle; Sadder, Maya

    2011-01-01

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

  7. 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...

  8. Portable File Format (PFF) specifications.

    SciTech Connect

    Dolan, Daniel H.,

    2015-02-01

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

  9. Star formation in the multiverse

    SciTech Connect

    Bousso, Raphael; Leichenauer, Stefan

    2009-03-15

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

  10. The Apennine Bench Formation revisited

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

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

  11. SAS FORMATS: USES AND ABUSES

    EPA Science Inventory

    SAS formats are a very powerful tool. They allow you to display the data in a more readable manner without modifying 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...

  12. 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 ...

  13. Physics of primordial star formation

    NASA Astrophysics Data System (ADS)

    Yoshida, Naoki

    2012-09-01

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

  14. Core formation by giant impacts

    NASA Technical Reports Server (NTRS)

    Tonks, W. B.; Melosh, H. J.

    1991-01-01

    Ideas about the accretion and early evolution of the Earth and the other terrestrial planets have recently undergone a number of revolutionary changes. It has become clear that giant impacts were far from rare events. In the later stages of accretion any given planetary embryo is liable to be struck several times by other bodies of up to half its own diameter. Such an impact may have the ability to trigger core formation. Traditional accretion models have had great difficulty explaining the formation of the core. If one admits the importance of infrequent large events that may melt an entire hemisphere, the core formation difficulty vanishes. Millimeter-size iron blebs in the melted region will rain out due to their density difference with the silicate melt. Core formation may not require the melting of the entire hemisphere of the planet. The conditions are explored under which impact induced core formation may occur.

  15. Digital geologic map of Fawnskin 7.5' quadrangle, San Bernardino County, California

    USGS Publications Warehouse

    Miller, F.K.; Matti, J.C.; Brown, H.J.; Powell, R.E.

    2001-01-01

    a. This Readme; includes in Appendix I, data contained in fskn_met.txt b. The same graphic as plotted in 2 above. (Test plots from this .pdf do not produce 1:24,000-scale maps. Adobe Acrobat page-size settings control map scale.) This release includes features not found in most other digital geologic maps, in that all polygons, lines, and points in the coverage are encoded with detailed, comprehensive geologic data contained in six INFO data tables (.rel). (See Matti and others, 1998a, 1998b, and 1998c, for information on how the encoding may be accessed and utilized.) No paper map is included in the Open-File Report, but a PostScript plot file containing an image of the geologic map sheet, topographic base, Correlation of Map Units (CMU), and detailed Description of Map Units (DMU) is. The Correlation of Map Units and Description of Map Units are in the editorial format of USGS Miscellaneous Investigations Series maps (I-maps) but have not been edited to comply with I-map standards. Within the geologic map data package, map units are identified by such standard geologic-map criteria as formation name, age, and lithology. Even though this is an author-prepared report, every attempt has been made to closely adhere to the stratigraphic nomenclature of the U.S. Geological Survey. Descriptions of units can be obtained by viewing or plotting the .pdf file (3b above) or plotting the PostScript file (2 above). If roads in some areas, especially roads that parallel topographic contours, do not show well on plots of the geologic map, we recommend use of the USGS Fawnskin 7.5' topographic quadrangle in conjunction with the geologic map.

  16. Geologic map of the Lake Mathews 7.5' quadrangle, Riverside County, California

    USGS Publications Warehouse

    Morton, Douglas M.; Weber, F. Harold

    2001-01-01

    a. This Readme; includes in Appendix I, data contained in lkm_met.txt b. The same graphic as plotted in 2 above. Test plots have not produced 1:24,000-scale map sheets. Adobe Acrobat page size setting influences map scale. The Correlation of Map Units and Description of Map Units is in the editorial format of USGS Miscellaneous Investigations Series (I-series) maps but has not been edited to comply with I-map standards. Within the geologic map data package, map units are identified by standard geologic map criteria such as formation-name, age, and lithology. Where known, grain size is indicated on the map by a subscripted letter or letters following the unit symbols as follows: lg, large boulders; b, boulder; g, gravel; a, arenaceous; s, silt; c, clay; e.g. Qyfa is a predominantly young alluvial fan deposit that is arenaceous.Multiple letters are used for more specific identification or for mixed units, e.g., Qfysa is a silty sand.In some cases, mixed units are indicated by a compound symbol; e.g., Qyf2sc. Marine deposits are in part overlain by local, mostly alluvial fan, deposits and are labeled Qomf. Grain size follows f. Even though this is an Open-File report and includes the standard USGS Open-File disclaimer, the report closely adheres to the stratigraphic nomenclature of the U.S. Geological Survey. Descriptions of units can be obtained by viewing or plotting the .pdf file (3b above) or plotting the postscript file (2 above).

  17. Geologic map of the Corona South 7.5' quadrangle, Riverside and Orange counties, California

    USGS Publications Warehouse

    Gray, C.H., Jr.; Morton, Douglas M.; Weber, F. Harold, Jr.; Digital preparation by Bovard, Kelly R.; O'Brien, Timothy

    2002-01-01

    a. A Readme file; includes in Appendix I, data contained in crs_met.txt b. The same graphic as plotted in 2 above. Test plots have not produced 1:24,000-scale map sheets. Adobe Acrobat page size setting influences map scale. The Correlation of Map Units and Description of Map Units is in the editorial format of USGS Geologic Investigations Series (I-series) maps but has not been edited to comply with I-map standards. Within the geologic map data package, map units are identified by standard geologic map criteria such as formation-name, age, and lithology. Where known, grain size is indicated on the map by a subscripted letter or letters following the unit symbols as follows: lg, large boulders; b, boulder; g, gravel; a, arenaceous; s, silt; c, clay; e.g. Qyfa is a predominantly young alluvial fan deposit that is arenaceous. Multiple letters are used for more specific identification or for mixed units, e.g., Qfysa is a silty sand. In some cases, mixed units are indicated by a compound symbol; e.g., Qyf2sc. Marine deposits are in part overlain by local, mostly alluvial fan, deposits and are labeled Qomf. Grain size follows f. Even though this is an Open-File Report and includes the standard USGS Open-File disclaimer, the report closely adheres to the stratigraphic nomenclature of the U.S. Geological Survey. Descriptions of units can be obtained by viewing or plotting the .pdf file (3b above) or plotting the postscript file (2 above).

  18. Dynamics of Earth orbiting formations

    NASA Technical Reports Server (NTRS)

    Ploen, Scott R.; Scharf, Daniel P.; Hadaegh, Fred Y.; Acikmese, Ahmed B.

    2004-01-01

    In this paper the equations of motion of a formation consisting of n spacecraft in Earth orbit are derived via Lagrange's equations. The equations of motion of the formation are developed with respect to both (1) a bound Keplerian reference orbit, and (2) a specific spacecraft in the formation. The major orbital perturbations acting on a formation in low Earth orbit are also included in the analysis. In contrast to the traditional approach based on the balance of linear momentum, the use of Lagrange's equations leads to a high-level matrix derivation of the formation equations of motion. The matrix form of the nonlinear motion equations is then linearized about a bound Keplerian reference orbit. Next, it is demonstrated that under the assumption of a circular reference orbit, the linearized equations of motion reduce to the well-known Hill-Clohessy-Wiltshire equations. The resulting linear and nonlinear dynamic equations lead to maximal physical insight into the structure of formation dynamics, and are ideally suited for use in the design and validation of formation guidance and control laws.

  19. Dynamics of rock varnish formation

    SciTech Connect

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

    1991-01-01

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

  20. Antihydrogen Formation using Cold Plasmas

    SciTech Connect

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

    2004-10-20

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

  1. Dissipative processes in galaxy formation.

    PubMed Central

    Silk, J

    1993-01-01

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

  2. Dynamics of interfacial pattern formation

    NASA Technical Reports Server (NTRS)

    Ben-Jacob, E.; Goldenfeld, N.; Langer, J. S.; Schon, G.

    1983-01-01

    A phenomenological model of dendritic solidification incorporating interfacial kinetics, crystalline anisotropy, and a local approximation for the dynamics of the thermal diffusion field is proposed. The preliminary results are in qualitative agreement with natural dendrite-like pattern formation.

  3. Conduction heating of hydrocarbonaceous formations

    SciTech Connect

    Bridges, J. E.

    1985-10-08

    A waveguide structure is emplanted in the earth to bound a particular volume of an earth formation with a waveguide structure formed of respective rows of discrete elongated electrodes wherein the spacing between rows is greater than the distance between electrodes in a respective row and in the case of vertical electrodes substantially less than the thickness of the hydrocarbonaceous earth formation. Electrical power at no more than a relatively low frequency is applied between respective rows of the electrodes to deliver power to the formation while producing relatively uniform heating thereof and limiting the relative loss of heat to adjacent barren regions to less than a tolerable amount. At the same time the temperature of the electrodes is controlled near the vaporization point of water thereat to maintain an electrically conductive path between the electrodes and the formation.

  4. Maximum likelihood topographic map formation.

    PubMed

    Van Hulle, Marc M

    2005-03-01

    We introduce a new unsupervised learning algorithm for kernel-based topographic map formation of heteroscedastic gaussian mixtures that allows for a unified account of distortion error (vector quantization), log-likelihood, and Kullback-Leibler divergence. PMID:15802004

  5. Immigration, Integration and Ghetto Formation

    NASA Astrophysics Data System (ADS)

    Meyer-Ortmanns, Hildegard

    We study ghetto formation in a population with natives and immigrants in the framework of the two-dimensional Ising-model with Kawasaki-exchange dynamics. It is the phase structure of the Ising model, the integration speed and the immigration rate which determine whether ghetto formation between natives and immigrants can be avoided or not. Our simulations are performed in- and out-of-equilibrium.

  6. Cosmic strings and galaxy formation

    NASA Technical Reports Server (NTRS)

    Bertschinger, Edmund

    1989-01-01

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

  7. Modes of clustered star formation

    NASA Astrophysics Data System (ADS)

    Pfalzner, S.; Kaczmarek, T.; Olczak, C.

    2012-09-01

    Context. The recent realization that most stars form in clusters, immediately raises the question of whether star and planet formation are influenced by the cluster environment. The stellar density in the most prevalent clusters is the key factor here. Whether dominant modes of clustered star formation exist is a fundamental question. Using near-neighbour searches in young clusters, Bressert and collaborators claim this not to be the case. They conclude that - at least in the solar neighbourhood - star formation is continuous from isolated to densely clustered environments and that the environment plays a minor role in star and planet formation. Aims: We investigate under which conditions near-neighbour searches in young clusters can distinguish between different modes of clustered star formation. Methods: Model star clusters with different memberships and density distributions are set up and near-neighbour searches are performed. We investigate the influence of the combination of different cluster modes, observational biases, and types of diagnostic on the results. Results: We find that the specific cluster density profile, the relative sample sizes, the limitations of the observation, and the choice of diagnostic method decide, whether modelled modes of clustered star formation are detected by near-neighbour searches. For density distributions that are centrally concentrated but span a wide density range (for example, King profiles), separate cluster modes are only detectable under ideal conditions (sample selection, completeness) if the mean density of the individual clusters differs by at least a factor of ~65. Introducing a central cut-off can lead to an underestimate of the mean density by more than a factor of ten especially in high density regions. The environmental effect on star and planet formation is similarly underestimated for half of the population in dense systems. Conclusions: Local surface-density distributions are a very useful tool for single

  8. Treating tar sands formations with karsted zones

    SciTech Connect

    Vinegar, Harold J.; Karanikas, John Michael

    2010-03-09

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

  9. The Dynamics of Latifundia Formation

    PubMed Central

    Chaves, Luis Fernando

    2013-01-01

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

  10. The dynamics of latifundia formation.

    PubMed

    Chaves, Luis Fernando

    2013-01-01

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

  11. Modeling of Mitochondrial Donut Formation.

    PubMed

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

    2015-09-01

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

  12. The Physics of Planetesimal Formation

    NASA Astrophysics Data System (ADS)

    Simon, Jacob; Armitage, Philip; Youdin, Andrew; Li, Rixin

    2015-12-01

    Planetesimals are the precursors to planets, and understanding their formation is an essential step towards developing a complete theory of planet formation. For small solid particles (e.g., dust grains) to coagulate into planetesimals, however, requires that these particles grow beyond centimeter sizes; with traditional coagulation physics, this is very difficult. The streaming instability, which is a clumping process akin to the pile-up of cars in a traffic jam, generates sufficiently high solid densities that the mutual gravity between the clumped particles eventually causes their collapse towards planetesimal mass and size scales. Exploring this transition from dust grains to planetesimals is still in its infancy but is extremely important if we want to understand the basics of planet formation. Here, I present a series of high resolution, first principles numerical simulations of potoplanetary disk gas and dust to study the clumping of particles via the streaming instability and the subsequent collapse towards planetesimals. These simulations have been employed to characterize the planetesimal population as a function of radius in protoplanetary disks. The results of these simulations will be crucial for planet formation models to correctly explain the formation and configuration of solar systems.

  13. Star formation in Galactic flows

    NASA Astrophysics Data System (ADS)

    Smilgys, Romas; Bonnell, Ian A.

    2016-06-01

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

  14. SW New Mexico Oil Well Formation Tops

    DOE Data Explorer

    Shari Kelley

    2015-10-21

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

  15. Formative Evaluation in the Performance Context.

    ERIC Educational Resources Information Center

    Dick, Walter; King, Debby

    1994-01-01

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

  16. Mathematical Models for Somite Formation

    PubMed Central

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

    2009-01-01

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

  17. Granuloma Formation in Pulmonary Sarcoidosis

    PubMed Central

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

    2013-01-01

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

  18. An XML portable chart format.

    PubMed Central

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

    1998-01-01

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

  19. Supershells and propagating star formation

    NASA Technical Reports Server (NTRS)

    Maclow, M. M.; Mccray, R.; Kafatos, M.

    1986-01-01

    Correlated supernovae from an OB association can carve large cavities (greater than 100 pc) in the interstellar medium (ISM), and can punch holes completely through the disk of a spiral galaxy. Supernova remnant energy within such a cavity is thermalized before the shock reaches the supershell. Thus stellar wind theory may be used to model these superbubbles. We describe how the evolution of the superbubble depends on the density distribution of the galactic disk gas and the rate of supernovae in the OB association. At a radius of 100 to 300 pc, the supershell becomes gravitationally unstable, forming giant molecular clouds which are the sites for new star formation. This gravitational instability of the supershells provides a physical mechanism for propagating star formation and may account for the observation of bursts of star formation in galaxies.

  20. Star formation in unperturbed LIRGs

    NASA Astrophysics Data System (ADS)

    Fuentes-Carrera, I.; Olguín, L.; Ambrocio-Cruz, P.; Verley, S.; Rosado, M.; Verdes-Montenegro, L.; Repetto, P.; Vázquez, C.; Aguilera, V.

    2011-10-01

    Luminous infrared galaxies (LIRGs) are galaxies with L_{FIR} > 10^11 L_{sun} (Sanders & Mirabel 1996). For a star-forming galaxy to emit at a LIRG level, it must have a very high star formation rate (SFR). In the local Universe, the star formation (SF) is primarily triggered by interactions. However, at intermediate redshift, a large fraction of LIRGs are disk galaxies with little sign of recent merger activity (Zheng et al. 2004). The question arises whether the intermediate redshift LIRGs are ``triggered'' or experiencing ``normal'', if elevated, SF. Understanding these SF processes is important since this type of systems may have contributed to 20% or more of the cosmic star-formation rate in the early Universe (Blain & Phillips 2002).

  1. Angular momentum and star formation

    NASA Astrophysics Data System (ADS)

    Strittmatter, P. A.

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

  2. Formation dynamics in geostationary ring

    NASA Astrophysics Data System (ADS)

    Spiridonova, Sofya

    2016-08-01

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

  3. Pattern formation in multiplex networks

    PubMed Central

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

    2015-01-01

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

  4. Bundle Formation in Biomimetic Hydrogels.

    PubMed

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

    2016-08-01

    Bundling of single polymer chains is a crucial process in the formation of biopolymer network gels that make up the extracellular matrix and the cytoskeleton. This bundled architecture leads to gels with distinctive properties, including a large-pore-size gel formation at very low concentrations and mechanical responsiveness through nonlinear mechanics, properties that are rarely observed in synthetic hydrogels. Using small-angle X-ray scattering (SAXS), we study the bundle formation and hydrogelation process of polyisocyanide gels, a synthetic material that uniquely mimics the structure and mechanics of biogels. We show how the structure of the material changes at the (thermally induced) gelation point and how factors such as concentration and polymer length determine the architecture, and with that, the mechanical properties. The correlation of the gel mechanics and the structural parameters obtained from SAXS experiments is essential in the design of future (synthetic) mimics of biopolymer networks. PMID:27409975

  5. Formation dynamics in geostationary ring

    NASA Astrophysics Data System (ADS)

    Spiridonova, Sofya

    2016-05-01

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

  6. Jet-Induced Star Formation

    SciTech Connect

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

    2003-12-16

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

  7. The MARC II Format: A Communications Format for Bibliographic Data.

    ERIC Educational Resources Information Center

    Avram, Henriette D.; And Others

    Utilizing both the experience gained from the Machine-Readable Cataloging (MARC) Pilot Project, which tested the feasibility of distributing Library of Congress cataloging in machine readable form to various users, and the results of extensive consultation with the library community and persons at the Library of Congress, a format for…

  8. Formation Flying In Highly Elliptical Orbits Initializing the Formation

    NASA Technical Reports Server (NTRS)

    Mailhe, Laurie; Schiff, Conrad; Hughes, Steven

    2000-01-01

    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.

  9. Formation of the first stars.

    PubMed

    Bromm, Volker

    2013-11-01

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

  10. Pattern formation in the geosciences

    PubMed Central

    Goehring, Lucas

    2013-01-01

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

  11. Ice formation in amorphous cellulose

    NASA Astrophysics Data System (ADS)

    Czihak, C.; Müller, M.; Schober, H.; Vogl, G.

    2000-03-01

    We investigate the formation of ice in wet amorphous cellulose in the temperature range of 190 K⩽T⩽280 K. Due to voids and pores in the cellulose film, water molecules are able to form crystalline aggregates. Beyond that, water is able to penetrate between cellulose chains where it can adsorb to hydroxyl side groups. From diffraction data we suggest an aggregation of low-density amorphous (lda) ice at cellulose surfaces. The formation of lda ice shows a clear temperature dependence which will be discussed together with recent inelastic neutron scattering results.

  12. High-Mass Star Formation

    NASA Astrophysics Data System (ADS)

    Schilke, P.

    2016-05-01

    A review on current theories and observations of high-mass star formation is given. Particularly the influence of magnetic fields and feedback mechanisms, and of varying initial conditions on theories are discussed. The, in my biased view, most important observations to put strong constraints on models of high-mass star formation are presented, in particular bearing on the existence and properties of high-mass starless cores, the role of filaments in the mass transport to high-mass cores, and the properties of disks around high-mass stars.

  13. Star formation and its triggers

    NASA Astrophysics Data System (ADS)

    Combes, F.

    2016-06-01

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

  14. Star formation and gas supply

    NASA Astrophysics Data System (ADS)

    Catinella, B.

    2016-06-01

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

  15. Star formation and extinct radioactivities

    NASA Technical Reports Server (NTRS)

    Cameron, A. G. W.

    1984-01-01

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

  16. NASA Space Mechanisms Handbook and Reference Guide Expanded Into CD-ROM Set

    NASA Technical Reports Server (NTRS)

    Fusaro, Robert L.

    2002-01-01

    Several NASA missions suffered failures and anomalies due to problems in applying space mechanisms technology to specific projects. Research shows that engineers often lack either adequate knowledge of mechanism design or sufficient understanding of how mechanisms affect sensitive systems. The Space Mechanisms Project conducted a Lessons Learned study and published a Space Mechanisms Handbook to help space industry engineers avoid recurring design, qualification, and application problems. The Space Mechanisms Handbook written at the NASA Glenn Research Center details the state-of-the-art in space mechanisms design as of 1998. NASA's objective in developing this Space Mechanisms Handbook was to provide readily accessible information on such areas as space mechanisms design, mechanical component availability and use, testing and qualification of mechanical systems, and a listing of worldwide space mechanisms experts and testing facilities in the United States. This handbook has been expanded into a two-volume CD-ROM set in an Adobe Acrobat format. In addition to the handbook, the CD's include (1) the two volume Space Mechanisms Lessons Learned Study, (2) proceedings from all the NASA hosted Aerospace Mechanisms Symposia held through the year 2000, (3) the Space Materials Handbook, (4) the Lubrication Handbook for the Space Industry, (5) the Structural & Mechanical Systems Long-Life Assurance Design Guidelines, (6) the Space Environments and Effects Source-Book, (7) the Spacecraft Deployable Appendages manual, (8) the Fastener Design Manual, (9) A Manual for Pyrotechnic Design, Development and Qualification, (10) the Report on Alternative Devices to Pyrotechnics on Spacecraft, and (11) Gearing (a manual). In addition, numerous other papers on tribology and lubrication are included.This technical summary of the project provides information on how to obtain the handbook and related information.

  17. Star formation across galactic environments

    NASA Astrophysics Data System (ADS)

    Young, Jason

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

  18. Star formation in distant galaxies.

    NASA Astrophysics Data System (ADS)

    Rocca-Volmerange, B.

    Scenarios of galactic evolution, essentially based on our knowledge of nearby galaxies have been proposed. Star formation laws, initial mass function, metallicity are the main parameters. The author shortly reviews the present status of these parameters in distant galaxies and gives some deductive conclusions from a comparison with the most distant (z ≥ 3) galaxies.

  19. Formative Assessment in Dance Education

    ERIC Educational Resources Information Center

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

    2015-01-01

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

  20. Formative Considerations Using Integrative CALL.

    ERIC Educational Resources Information Center

    Callahan, Philip; Shaver, Peter

    2001-01-01

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

  1. Cloud formation in substellar atmospheres

    NASA Astrophysics Data System (ADS)

    Helling, Christiane

    2009-02-01

    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 microphysical 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.

  2. Biofilm formation in Streptococcus pneumoniae.

    PubMed

    Domenech, Mirian; García, Ernesto; Moscoso, Miriam

    2012-07-01

    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

  3. Biofilm formation in Streptococcus pneumoniae

    PubMed Central

    Domenech, Mirian; García, Ernesto; Moscoso, Miriam

    2012-01-01

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

  4. Constraints on galaxy formation theories

    NASA Technical Reports Server (NTRS)

    Szalay, A. S.

    1986-01-01

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

  5. Stereotype Formation: Biased by Association

    ERIC Educational Resources Information Center

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

    2010-01-01

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

  6. Formative Assessment: A Cybernetic Viewpoint

    ERIC Educational Resources Information Center

    Roos, Bertil; Hamilton, David

    2005-01-01

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

  7. The EPRDATA Format: A Dialogue

    SciTech Connect

    Hughes, III, Henry Grady

    2015-08-18

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

  8. Formative Assessment in Primary Science

    ERIC Educational Resources Information Center

    Loughland, Tony; Kilpatrick, Laetitia

    2015-01-01

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

  9. Amyloid Beta Mediates Memory Formation

    ERIC Educational Resources Information Center

    Garcia-Osta, Ana; Alberini, Cristina M.

    2009-01-01

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

  10. Chevrons formation in laminar erosion

    NASA Astrophysics Data System (ADS)

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

    2007-11-01

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

  11. SAS FORMATS: USES AND ABUSES

    EPA Science Inventory

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

  12. Monogamy of entanglement of formation

    NASA Astrophysics Data System (ADS)

    de Oliveira, Thiago R.; Cornelio, Marcio F.; Fanchini, Felipe F.

    2014-03-01

    It is well known that a particle cannot freely share entanglement with two or more particles. This restriction is generally called monogamy. However the formal quantification of such restriction is only known for some measures of entanglement and for two-level systems. The first and broadly known monogamy relation was established by Coffman, Kundu, and Wootters for the square of the concurrence. Since then, it is usually said that the entanglement of formation is not monogamous, as it does not obey the same relation. We show here that despite that, the entanglement of formation cannot be freely shared and therefore should be said to be monogamous. Furthermore, the square of the entanglement of formation does obey the same relation of the squared concurrence, a fact recently noted for three particles and extended here for N particles. Therefore the entanglement of formation is as monogamous as the concurrence. We also numerically study how the entanglement is distributed in pure states of three qubits and the relation between the sum of the bipartite entanglement and the classical correlation.

  13. Audiences for Contemporary Radio Formats.

    ERIC Educational Resources Information Center

    Lull, James T.; And Others

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

  14. Multiple cilia suppress tumour formation.

    PubMed

    Eberhart, Charles

    2016-04-01

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

  15. Pattern Formation in Convective Instabilities

    NASA Astrophysics Data System (ADS)

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

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

  16. A standard audit trail format

    SciTech Connect

    Bishop, M.

    1995-02-01

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

  17. Peripheral Leptin Regulates Bone Formation

    PubMed Central

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

    2012-01-01

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

  18. Inside-out Planet Formation

    NASA Astrophysics Data System (ADS)

    Chatterjee, Sourav; Tan, Jonathan C.

    2014-01-01

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

  19. Inside-out planet formation

    SciTech Connect

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

    2014-01-01

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

  20. Let's Connect: Using Adobe Connect to Foster Group Collaboration in the Online Classroom

    ERIC Educational Resources Information Center

    Kaufmann, Renee; Frisby, Brandi N.

    2013-01-01

    The need for students to become connected in the classroom parallels the need for students to become socially integrated into the college community. Because technological tools are always changing, the opportunity for all students on- and off-campus to ''meet'' face-to-face and build relationships within the classroom are…

  1. 40 CFR 1502.10 - Recommended format.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

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

  2. What Is Formation? A Conceptual Discussion

    ERIC Educational Resources Information Center

    Sutphen, Molly; de Lange, Thomas

    2015-01-01

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

  3. Method of fracturing a geological formation

    DOEpatents

    Johnson, James O.

    1990-01-01

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

  4. ASDF: A new data format for astronomy

    NASA Astrophysics Data System (ADS)

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

    2015-09-01

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

  5. 76 FR 98 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Amendment 5 to the Golden Crab...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-03

    ...: Karla Gore, Southeast Regional Office, NMFS, 263 13th Avenue South, St. Petersburg, FL 33701... Word, Excel, WordPerfect, or Adobe PDF file formats only. FOR FURTHER INFORMATION CONTACT: Karla...

  6. 77 FR 67327 - Fisheries Off West Coast States; West Coast Salmon Fisheries; Notice of Availability for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-09

    ... approve Amendment 17 to the FMP. In 2011, the Council transmitted Salmon FMP Amendment 16 to NMFS (76 FR... Word, Excel, WordPerfect, or Adobe PDF file formats only. Electronic copies of the amendment may...

  7. 76 FR 5555 - Fisheries of the Northeastern United States; Monkfish; Amendment 5

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-01

    ... bring the Monkfish FMP into compliance with recently revised National Standard 1 (NS1) Guidelines (74 FR... electronic comments in Microsoft Word, Excel, WordPerfect, or Adobe PDF file formats only. FOR...

  8. 77 FR 16950 - Fisheries of the Exclusive Economic Zone Off Alaska; Pollock in Statistical Area 630 in the Gulf...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-23

    ... FR 14698, March 13, 2012). As of March 15, 2012, NMFS has determined that approximately 1,389 metric... accepted in Microsoft Word or Excel, WordPerfect, or Adobe PDF file formats only. FOR FURTHER...

  9. 76 FR 11393 - Fisheries of the Exclusive Economic Zone Off Alaska; Pollock in Statistical Area 630 in the Gulf...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-02

    ... (76 FR 4082, January 24, 2011). As of February 24, 2011, NMFS has determined that approximately 4,141... electronic comments in Microsoft Word, Excel, WordPerfect, or Adobe PDF file formats only. FOR...

  10. 75 FR 57702 - Fisheries of the Exclusive Economic Zone Off Alaska; Pollock in Statistical Area 630 of the Gulf...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-22

    ...)(iii) on August 27, 2010 (75 FR 52891, August 30, 2010). NMFS has determined that approximately 4,580... accepted in Microsoft Word, Excel, WordPerfect, or Adobe portable document file (pdf) formats only....

  11. 78 FR 21347 - Supplemental Draft Environmental Impact Statement for Effects of Oil and Gas Activities in the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-10

    ... content of the Supplemental DEIS can be found in the Notice of Availability (78 FR 19212, March 29, 2013...). Attachments to electronic comments will be accepted in Microsoft Word or Excel or Adobe PDF file formats...

  12. 76 FR 13097 - Fisheries of the Exclusive Economic Zone Off Alaska; Pollock in Statistical Area 630 in the Gulf...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-10

    ... (76 FR 11393, March 2, 2011). As of March 2, 2011, NMFS has determined that approximately 4,100 metric... electronic comments in Microsoft Word, Excel, WordPerfect, or Adobe PDF file formats only. FOR...

  13. Treating tar sands formations with dolomite

    SciTech Connect

    Vinegar, Harold J.; Karanikas, John Michael

    2010-06-08

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

  14. Rapid gas hydrate formation process

    SciTech Connect

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

    2013-01-15

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

  15. Formation of quasiparallel Alfven solitons

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

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

  16. Laser beam pulse formatting method

    DOEpatents

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

    1994-01-01

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

  17. Laser beam pulse formatting method

    DOEpatents

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

    1994-08-09

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

  18. The dynamics of city formation*

    PubMed Central

    Henderson, J. Vernon; Venables, Anthony J.

    2013-01-01

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

  19. Hydrogen Sulfide Inhibits Amyloid Formation

    PubMed Central

    2015-01-01

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

  20. THE BLACK HOLE FORMATION PROBABILITY

    SciTech Connect

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

    2015-02-01

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

  1. Line formation in turbulent media

    NASA Astrophysics Data System (ADS)

    Stahlberg, J.

    The methods of mean field electrodynamics are used to investigate the influence of stochastic velocity fields on line formation. Due to numerical difficulties in such concepts, only two point correlations are taken into account. But there are some difficulties: Different models can yield different profiles - for the same parameter - or vice versa, a different interpretation of the same profile can yield different correlation lengths and also different velocities. Care is required in interpreting these parameters as real hydrodynamics ones.

  2. Method for fracturing subterranean formations

    SciTech Connect

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

    1985-11-19

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

  3. The Black Hole Formation Probability

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

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

  4. Memory Formation Shaped by Astroglia.

    PubMed

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

    2015-01-01

    Astrocytes, the most heterogeneous glial cells in the central nervous system (CNS), execute a multitude of homeostatic functions and contribute to memory formation. Consolidation of synaptic and systemic memory is a prolonged process and hours are required to form long-term memory. In the past, neurons or their parts have been considered to be the exclusive cellular sites of these processes, however, it has now become evident that astrocytes provide an important and essential contribution to memory formation. Astrocytes participate in the morphological remodeling associated with synaptic plasticity, an energy-demanding process that requires mobilization of glycogen, which, in the CNS, is almost exclusively stored in astrocytes. Synaptic remodeling also involves bidirectional astroglial-neuronal communication supported by astroglial receptors and release of gliosignaling molecules. Astroglia exhibit cytoplasmic excitability that engages second messengers, such as Ca(2+), for phasic, and cyclic adenosine monophosphate (cAMP), for tonic signal coordination with neuronal processes. The detection of signals by astrocytes and the release of gliosignaling molecules, in particular by vesicle-based mechanisms, occurs with a significant delay after stimulation, orders of magnitude longer than that present in stimulus-secretion coupling in neurons. These particular arrangements position astrocytes as integrators ideally tuned to support time-dependent memory formation. PMID:26635551

  5. Vortex Formation in Shallow Flows

    NASA Astrophysics Data System (ADS)

    Rockwell, Donald

    2006-11-01

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

  6. Modeling of Dynamic FRC Formation

    NASA Astrophysics Data System (ADS)

    Mok, Yung; Barnes, Dan; Dettrick, Sean

    2010-11-01

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

  7. Theory of Planetary System Formation

    NASA Technical Reports Server (NTRS)

    Cassen, Patrick

    1996-01-01

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

  8. Theory of Remote Image Formation

    NASA Astrophysics Data System (ADS)

    Blahut, Richard E.

    2004-11-01

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

  9. Bubble migration during hydrate formation

    NASA Astrophysics Data System (ADS)

    Shagapov, V. Sh.; Chiglintseva, A. S.; Rusinov, A. A.

    2015-03-01

    A model of the process of migration of methane bubbles in water under thermobaric conditions of hydrate formation is proposed. The peculiarities of the temperature field evolution, migration rate, and changes in the radius and volume fraction of gas hydrate bubbles are studied. It is shown that, with a constant mass flow of gas from the reservoir bottom, for all parameters of the surfacing gas hydrate disperse system, there is a quasistationary pattern in the form of a "step"-like wave. Depending on the relationship of the initial gas bubble density with the average gas density in the hydrate composition determined by the depth from which bubbles rise to the surface, the final radius of hydrate particles may be larger or smaller than the initial gas bubble radii. It is established that the speed at which gas hydrate inclusions rise to the surface decreases by several times due to an increase in their weight during hydrate formation. The influence of the depth of the water reservoir whose bottom is a gas flow source on the dynamics of hydrate formation is studied.

  10. NSDF: Neuroscience Simulation Data Format.

    PubMed

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

    2016-04-01

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

  11. Dioxin formation from waste incineration.

    PubMed

    Shibamoto, Takayuki; Yasuhara, Akio; Katami, Takeo

    2007-01-01

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

  12. Core formation in silicate bodies

    NASA Astrophysics Data System (ADS)

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

    2008-12-01

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

  13. Feedback During Massive Star Formation

    NASA Astrophysics Data System (ADS)

    Tanaka, Kei; Tan, Jonathan C.; Zhang, Yichen

    2016-01-01

    We present models of photoionization of massive protostellar cores, and show the impact of this ionization feedback on the efficiency of star formation and its observational features. Based on the Core Accretion scenario, we construct the collapse model of rotating massive-protostellar cloud cores together with a protostellar evolutional calculation, including feedback effects from a MHD disk wind, photoionization and radiation pressure. First, the MHD wind creates a bipolar outflow whose opening angle increases over the timescale of mass accretion. The ionizing luminosity dramatically increases after the protostar reaches ~ 5 Msun due to Kelvin-Helmholz contraction, and the MHD wind is photoionized when the protostellar mass reaches ~ 10 - 20 Msun. As the ionizing and bolometric luminosities increase, the outflow opening angle becomes wider due to radiation pressure feedback. By this combination of feedback processes, the envelope is eroded and the mass infall rate is significantly reduced to that arriving only from the disk-shielded equatorial region. At a protostellar mass of ~ 50 - 100 Msun, depending on the initial core properties, the mass accretion is halted by disk photoevaporation. In this way, feedback significantly reduces the star formation efficiency when forming massive stars from massive cloud cores, which could produce a cutoff at the high-mass end of the initial mass function. Along this evolutionary calculation, we also compute the detailed structure of the photoionized regions using a ray-tracing radiative transfer code and evaluate their emission signatures. Their free-free continuum and recombination line emissions are consistent with the variety of observed radio sources associated with massive protostars, i.e., jets and ultra/hyper-compact HII regions. The comparison between our models and such observations enables us to better define the evolutionary sequence of massive star formation.

  14. Formation fracturing kills Indonesian blowout

    SciTech Connect

    Wizyodiazjo, S.; Salech, M.; Sumanta, K.

    1982-11-15

    Dynamic killing methods without fracturing could not be applied in killing PT-29 blowout, due to the reservoir rock properties (shaley sand formation). A special fracturing and acidizing technique was required in order to allow the calculated kill rate of 40 bbl/ min. A low injection rate of 0.5 bbl/min with high injection pressure of 1,250 psi occurred due to a degree of formation damage and the mud cake covering the sand face. The calculated formation fracture pressure of 1,393 psi was a reliable value compared to actual fracture pressure of 1,400 psi. The designed killing rate of 40 bbl/ min could not reach the blowout well due to some leak-off of the injected fluid in unexpected directions of the induced fractures. Clearing PT-29 of all debris was very important for immediate well capping. The capping operation was done after the fire was extinguished; although the well was still flowing gas and water, no hazard of explosion was detected. The exact subsurface position of the blowout well of PT-29 was uncertain due to the lack of directional survey data. This problem reduced the effectiveness of the killing operation. A reliable water supply is important to the success of the killing job. Once the fracture had been induced, kill fluid had to be pumped continuously; any interruption might cause the fracture to heal. Deviation and directional survey data on every vertical or directional well are absolutely important for accurate relief well drilling purposes in case it is required.

  15. Probabilistic Modeling of Rosette Formation

    PubMed Central

    Long, Mian; Chen, Juan; Jiang, Ning; Selvaraj, Periasamy; McEver, Rodger P.; Zhu, Cheng

    2006-01-01

    Rosetting, or forming a cell aggregate between a single target nucleated cell and a number of red blood cells (RBCs), is a simple assay for cell adhesion mediated by specific receptor-ligand interaction. For example, rosette formation between sheep RBC and human lymphocytes has been used to differentiate T cells from B cells. Rosetting assay is commonly used to determine the interaction of Fc γ-receptors (FcγR) expressed on inflammatory cells and IgG coated on RBCs. Despite its wide use in measuring cell adhesion, the biophysical parameters of rosette formation have not been well characterized. Here we developed a probabilistic model to describe the distribution of rosette sizes, which is Poissonian. The average rosette size is predicted to be proportional to the apparent two-dimensional binding affinity of the interacting receptor-ligand pair and their site densities. The model has been supported by experiments of rosettes mediated by four molecular interactions: FcγRIII interacting with IgG, T cell receptor and coreceptor CD8 interacting with antigen peptide presented by major histocompatibility molecule, P-selectin interacting with P-selectin glycoprotein ligand 1 (PSGL-1), and L-selectin interacting with PSGL-1. The latter two are structurally similar and are different from the former two. Fitting the model to data enabled us to evaluate the apparent effective two-dimensional binding affinity of the interacting molecular pairs: 7.19 × 10−5 μm4 for FcγRIII-IgG interaction, 4.66 × 10−3 μm4 for P-selectin-PSGL-1 interaction, and 0.94 × 10−3 μm4 for L-selectin-PSGL-1 interaction. These results elucidate the biophysical mechanism of rosette formation and enable it to become a semiquantitative assay that relates the rosette size to the effective affinity for receptor-ligand binding. PMID:16603493

  16. A Fossil Group in Formation

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

  17. Petrophysical evaluation of subterranean formations

    DOEpatents

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

    2013-05-28

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

  18. Formation Flying and Deformable Instruments

    SciTech Connect

    Rio, Yvon

    2009-05-11

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

  19. Zonal flow as pattern formation

    NASA Astrophysics Data System (ADS)

    Parker, Jeffrey B.; Krommes, John A.

    2013-10-01

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

  20. Zonal flow as pattern formation

    SciTech Connect

    Parker, Jeffrey B.; Krommes, John A.

    2013-10-15

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

  1. Relativistic jets and star formation

    NASA Astrophysics Data System (ADS)

    Bicknell, Geoffrey Vincent; Mukherjee, Dipanjan; Wagner, Alex; Slatyer Sutherland, Ralph

    2015-08-01

    We are conducting simulations of jets interacting with molecular and atomic gas on scales of a few kpc in forming galaxies. Competing processes, such as the dispersion of gas in the galaxy and star formation in the high-pressure environment determine whether positive or negative feedback predominates. We shall present our new simulations including an assessment of these different effects. Our simulations also predict the velocity and velocity dispersion of atomic and molecular gas in galaxies, which are undergoing interaction with relativistic jets. These results are of interest to radio and optical spectral imaging observations of galaxies undergoing feedback.

  2. Formation of Nanoporous Glass Layer

    NASA Astrophysics Data System (ADS)

    Grigoras, Kestutis; Franssila, Sami

    2004-01-01

    Porous layers have been formed in Pyrex glass by reactive ion etching (RIE). Chromium is used as an etch mask. Different etch gases (SF6, CF4/Ar) have been used, and depending on flow ratio, etch time and applied power, a dense array of high aspect ratio glass pillars with submicrometer dimensions was obtained instead of a smooth channel bottom. The pillars were about 500nm tall and 50 100nm in cross-section. The formation of porous layers is explained by the effect of mask material re-deposition during the plasma etching. Porous glass layers could have applications in chromatographic separations or microchemicalsample concentrators.

  3. XML Format for SESAME and LEOS

    SciTech Connect

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

    2009-04-29

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

  4. SAR polar format implementation with MATLAB.

    SciTech Connect

    Martin, Grant D.; Doerry, Armin Walter

    2005-11-01

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

  5. Possible mechanisms of macrolayer formation

    SciTech Connect

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

    1992-01-01

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

  6. Possible mechanisms of macrolayer formation

    SciTech Connect

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

    1992-05-01

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

  7. Multiresolution FOPEN SAR image formation

    NASA Astrophysics Data System (ADS)

    DiPietro, Robert C.; Fante, Ronald L.; Perry, Richard P.; Soumekh, Mehrdad; Tromp, Laurens D.

    1999-08-01

    This paper presents a new technique for FOPEN SAR (foliage penetration synthetic aperture radar) image formation of Ultra Wideband UHF radar data. Planar Subarray Processing (PSAP) has successfully demonstrated the capability of forming multi- resolution images for X and Ka band radar systems under MITRE IR&D and the DARPA IBC program. We have extended the PSAP algorithm to provide the capability to form strip map, multi- resolution images for Ultra Wideband UHF radar systems. The PSAP processing can accommodate very large SAR integration angles and the resulting very large range migration. It can also accommodate long coherent integration times and wide swath coverage. Major PSAP algorithm features include: multiple SAR sub-arrays providing different look angles at the same image area that can enable man-made target responses to be distinguished from other targets and clutter by their angle dependent specular characteristics, the capability to provide a full resolution image in these and other selected areas without the processing penalty of full resolution in non required areas, and the capability to include angle-dependent motion compensation within the image formation process.

  8. Early phases of star formation

    NASA Astrophysics Data System (ADS)

    Bok, B. J.

    1981-04-01

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

  9. BAR FORMATION FROM GALAXY FLYBYS

    SciTech Connect

    Lang, Meagan; Holley-Bockelmann, Kelly; Sinha, Manodeep E-mail: k.holley@vanderbilt.edu

    2014-08-01

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

  10. Microbubble formation from plasma polymers.

    PubMed

    Shahravan, Anaram; Yelamarty, Srinath; Matsoukas, Themis

    2012-09-27

    We document the formation of liquid-like particles in a toluene glow discharge that subsequently solidify via a process that releases hydrogen to form a solid microbubble with micrometer-size diameter, nanometer-size shell thickness, and high volume fraction, in excess of 90%. Liquid-like particles are produced in a toluene plasma under conditions that promote low degree of cross-linking (low power, high pressure). When these are transferred for observation in TEM, they are seen to transform under irradiation by the electron beam into solid bubbles with diameter of about 3 μm. This transformation also takes place under laser irradiation of sufficient power and under heating. We present evidence that the formation of these microbubbles is due to solidification of the liquid-like precursor that is accompanied by release of hydrogen. This mechanism is supported by a geometric model that provides a quantitative description of the particle size before and after solidification. These unique stimuli-responsive particles exhibit the potential of using temperature, electron beam, or laser as a source to change their size and structure which may find application in thermal insulators, lightweight materials, and light scattering agents. PMID:22954230

  11. In vitro Tumorsphere Formation Assays

    PubMed Central

    Johnson, Sara; Chen, Hexin; Lo, Pang-Kuo

    2016-01-01

    A tumorsphere is a solid, spherical formation developed from the proliferation of one cancer stem/progenitor cell. These tumorspheres (Figure 1a) are easily distinguishable from single or aggregated cells (Figure 1b) as the cells appear to become fused together and individual cells cannot be identified. Cells are grown in serum-free, non-adherent conditions in order to enrich the cancer stem/progenitor cell population as only cancer stem/progenitor cells can survive and proliferate in this environment. This assay can be used to estimate the percentage of cancer stem/progenitor cells present in a population of tumor cells. The size, which can vary from less than 50 micrometers to 250 micrometers, and number of tumorspheres formed can be used to characterize the cancer stem/progenitor cell population within a population of in vitro cultured cancer cells and within in vivo tumors (Lo et al., 2012; Liu et al., 2009). While several cell lines can be used for tumorsphere formation assay (e.g. primary mammary tumor cells from Her2/neu-transgenic mice, MCF7, BT474 and HCC1954), some cell lines may not form typical tumorsphere structures and may be difficult to count or classify definitively as tumorspheres.

  12. Coring in deep hardrock formations

    SciTech Connect

    Drumheller, D.S.

    1988-08-01

    The United States Department of Energy is involved in a variety of scientific and engineering feasibility studies requiring extensive drilling in hard crystalline rock. In many cases well depths extend from 6000 to 20,000 feet in high-temperature, granitic formations. Examples of such projects are the Hot Dry Rock well system at Fenton Hill, New Mexico and the planned exploratory magma well near Mammoth Lakes, California. In addition to these programs, there is also continuing interest in supporting programs to reduce drilling costs associated with the production of geothermal energy from underground sources such as the Geysers area near San Francisco, California. The overall progression in these efforts is to drill deeper holes in higher temperature, harder formations. In conjunction with this trend is a desire to improve the capability to recover geological information. Spot coring and continuous coring are important elements in this effort. It is the purpose of this report to examine the current methods used to obtain core from deep wells and to suggest projects which will improve existing capabilities. 28 refs., 8 figs., 2 tabs.

  13. Montezuma Formation of Costa Rica

    SciTech Connect

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

    1985-01-01

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

  14. Computer simulation of bubble formation.

    SciTech Connect

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

    2007-01-01

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

  15. Beaver assisted river valley formation

    USGS Publications Warehouse

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

    2011-01-01

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

  16. Marcelina formation study - Maracaibo basin

    SciTech Connect

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

    1996-08-01

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

  17. Tube Formation in Nanoscale Materials

    PubMed Central

    2008-01-01

    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

  18. Dilatational band formation in bone

    PubMed Central

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

    2012-01-01

    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

  19. Bar Formation from Galaxy Flybys

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

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

  20. Pattern formations and optimal packing.

    PubMed

    Mityushev, Vladimir

    2016-04-01

    Patterns of different symmetries may arise after solution to reaction-diffusion equations. Hexagonal arrays, layers and their perturbations are observed in different models after numerical solution to the corresponding initial-boundary value problems. We demonstrate an intimate connection between pattern formations and optimal random packing on the plane. The main study is based on the following two points. First, the diffusive flux in reaction-diffusion systems is approximated by piecewise linear functions in the framework of structural approximations. This leads to a discrete network approximation of the considered continuous problem. Second, the discrete energy minimization yields optimal random packing of the domains (disks) in the representative cell. Therefore, the general problem of pattern formations based on the reaction-diffusion equations is reduced to the geometric problem of random packing. It is demonstrated that all random packings can be divided onto classes associated with classes of isomorphic graphs obtained from the Delaunay triangulation. The unique optimal solution is constructed in each class of the random packings. If the number of disks per representative cell is finite, the number of classes of isomorphic graphs, hence, the number of optimal packings is also finite. PMID:26852668

  1. Hydraulic fracturing in subterranean formations

    SciTech Connect

    Borchardt, J.K.

    1991-06-18

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

  2. Protostellar formation in rotating interstellar clouds. VIII - Inner core formation

    NASA Technical Reports Server (NTRS)

    Boss, Alan P.

    1989-01-01

    The results are presented of a variety of spherically symmetric one-dimensional (1D) calculations intended to determine the robustness of the dynamical hiccup phenomenon in protostellar cores. The 1D models show that the phenomenon is relatively insensitive to changes in the equations of state, numerical resolution, initial density and temperature, and the radiative transfer approximation. In 1D, the hiccup results in an explosive destruction of the entire inner protostellar core. Inner core formation is studied with a sequence of three-dimensional models which show that rapid inner core rotation stabilizes the hiccup instability. Instead, the inner core becomes quite flat and undergoes a cycle of binary fragmentation, binary decay into a single object surrounded by a bar, breakup of the bar into a binary, etc. When lesser amounts of rotation are involved, the inner core does hiccup somewhat, but mass is ejected in only a few directions, leading to several broad streams of ejecta.

  3. Treating nahcolite containing formations and saline zones

    DOEpatents

    Vinegar, Harold J

    2013-06-11

    A method for treating a nahcolite containing subsurface formation includes removing water from a saline zone in or near the formation. The removed water is heated using a steam and electricity cogeneration facility. The heated water is provided to the nahcolite containing formation. A fluid is produced from the nahcolite containing formation. The fluid includes at least some dissolved nahcolite. At least some of the fluid is provided to the saline zone.

  4. String Formatting Considered Harmful for Novice Programmers

    ERIC Educational Resources Information Center

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

    2010-01-01

    In Java, "System.out.printf" and "String.format" consume a specialised kind of string commonly known as a format string. In our study of first-year students at the Ateneo de Manila University, we discovered that format strings present a substantial challenge for novice programmers. Focusing on their first laboratory we found that 8% of all the…

  5. 48 CFR 307.7103 - Format.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 4 2011-10-01 2011-10-01 false Format. 307.7103 Section 307.7103 Federal Acquisition Regulations System HEALTH AND HUMAN SERVICES COMPETITION AND ACQUISITION PLANNING ACQUISITION PLANNING Acquisition Plan 307.7103 Format. (a) HHS has established a standard format for preparing an AP. The template for...

  6. Transfer of Training with Formation Flight Trainer.

    ERIC Educational Resources Information Center

    Reid, Gary B.; Cyrus, Michael L.

    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…

  7. Formative Assessment: Responding to Your Students

    ERIC Educational Resources Information Center

    Tuttle, Harry Grover

    2009-01-01

    This "how-to" book on formative assessment is filled with practical suggestions for teachers who want to use formative assessment in their classrooms. With practical strategies, tools, and examples for teachers of all subjects and grade levels, this book shows you how to use formative assessment to promote successful student learning. Topics…

  8. Formative Constructs Implemented via Common Factors

    ERIC Educational Resources Information Center

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

    2011-01-01

    Recently there has been a renewed interest in formative measurement and its role in properly specified models. Formative measurement models are difficult to identify, and hence to estimate and test. Existing solutions to the identification problem are shown to not adequately represent the formative constructs of interest. We propose a new two-step…

  9. 49 CFR 563.8 - Data format

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 6 2010-10-01 2010-10-01 false Data format 563.8 Section 563.8 Transportation..., DEPARTMENT OF TRANSPORTATION EVENT DATA RECORDERS § 563.8 Data format (a) The data elements listed in Tables... specified in Table III Table III—Reported Data Element Format Data element Minimum range Accuracy...

  10. 49 CFR 563.8 - Data format.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 6 2013-10-01 2013-10-01 false Data format. 563.8 Section 563.8 Transportation..., DEPARTMENT OF TRANSPORTATION EVENT DATA RECORDERS § 563.8 Data format. (a) The data elements listed in Tables... specified in Table III Table III—Reported Data Element Format Data element Minimum range Accuracy...

  11. 7 CFR 1755.407 - Data formats.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 11 2011-01-01 2011-01-01 false Data formats. 1755.407 Section 1755.407 Agriculture... TELECOMMUNICATIONS POLICIES ON SPECIFICATIONS, ACCEPTABLE MATERIALS, AND STANDARD CONTRACT FORMS § 1755.407 Data formats. The following suggested formats listed in this section may be used for recording the test...

  12. 7 CFR 1755.407 - Data formats.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 11 2010-01-01 2010-01-01 false Data formats. 1755.407 Section 1755.407 Agriculture... TELECOMMUNICATIONS POLICIES ON SPECIFICATIONS, ACCEPTABLE MATERIALS, AND STANDARD CONTRACT FORMS § 1755.407 Data formats. The following suggested formats listed in this section may be used for recording the test...

  13. 7 CFR 1755.407 - Data formats.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 11 2012-01-01 2012-01-01 false Data formats. 1755.407 Section 1755.407 Agriculture... TELECOMMUNICATIONS POLICIES ON SPECIFICATIONS, ACCEPTABLE MATERIALS, AND STANDARD CONTRACT FORMS § 1755.407 Data formats. The following suggested formats listed in this section may be used for recording the test...

  14. 49 CFR 563.8 - Data format.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 6 2014-10-01 2014-10-01 false Data format. 563.8 Section 563.8 Transportation..., DEPARTMENT OF TRANSPORTATION EVENT DATA RECORDERS § 563.8 Data format. (a) The data elements listed in Tables... specified in Table III Table III—Reported Data Element Format Data element Minimum range Accuracy...

  15. 7 CFR 1755.407 - Data formats.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 11 2013-01-01 2013-01-01 false Data formats. 1755.407 Section 1755.407 Agriculture... TELECOMMUNICATIONS POLICIES ON SPECIFICATIONS, ACCEPTABLE MATERIALS, AND STANDARD CONTRACT FORMS § 1755.407 Data formats. The following suggested formats listed in this section may be used for recording the test...

  16. 7 CFR 1755.407 - Data formats.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 11 2014-01-01 2014-01-01 false Data formats. 1755.407 Section 1755.407 Agriculture... TELECOMMUNICATIONS POLICIES ON SPECIFICATIONS, ACCEPTABLE MATERIALS, AND STANDARD CONTRACT FORMS § 1755.407 Data formats. The following suggested formats listed in this section may be used for recording the test...

  17. 40 CFR 610.17 - Application format.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 30 2011-07-01 2011-07-01 false Application format. 610.17 Section 610... RETROFIT DEVICES Test Procedures and Evaluation Criteria General Provisions § 610.17 Application format. (a... application format, in order to allow the Administrator to compile relevant data on specific devices and...

  18. A new PICL trace file format

    SciTech Connect

    Worley, P.H.

    1992-10-01

    A trace file format is described that will be used in future releases of the Portable Instrumented Communication Library (PICL) and ParaGraph. The new format provides improved support for tracing and profiling PICL communication primitives and user-defined events. The new format is also easily extended and may be useful in other instrumentation packages and performance visualization tools.

  19. Formative Assessment: Policy, Perspectives and Practice

    ERIC Educational Resources Information Center

    Clark, Ian

    2011-01-01

    Proponents of formative assessment (FA) assert that students develop a deeper understanding of their learning when the essential components of formative feedback and cultural responsiveness are effectively incorporated as central features of the formative assessment process. Even with growing international agreement among the research community…

  20. Diet History Questionnaire II: Size Formats

    Cancer.gov

    Two serving size formats are used on the NCI versions of the DHQ as shown below. Format 1 is used for nearly all serving size questions. Format 2 is used only in special cases, where 'never' is allowed as a response.

  1. Successful Student Writing through Formative Assessment

    ERIC Educational Resources Information Center

    Tuttle, Harry Grover

    2010-01-01

    Use formative assessment to dramatically improve your students' writing. In "Successful Student Writing Through Formative Assessment", educator and international speaker Harry G. Tuttle shows you how to guide middle and high school students through the prewriting, writing, and revision processes using formative assessment techniques that work.…

  2. Formative Assessment: Guidance for Early Childhood Policymakers

    ERIC Educational Resources Information Center

    Riley-Ayers, Shannon

    2014-01-01

    This policy report provides a guide and framework to early childhood policymakers considering formative assessment. The report defines formative assessment and outlines its process and application in the context of early childhood. The substance of this document is the issues for consideration in the implementation of the formative assessment…

  3. Composition and method of stimulating subterranean formations

    SciTech Connect

    Dill, W.R.; Walker, M.L.; Ford, G.F.

    1987-07-14

    This patent describes a method of treating a subterranean formation containing iron comprising contacting a subterranean formation with an aqueous fluid containing a compound consisting essentially of at least one member selected from the group consisting of: dihydroxymaleic acid, salts of dihydroxymaleic acid, glucono-deltalactone present in an amount sufficient to prevent the precipitation of ferric iron during contact with the subterranean formation.

  4. 21 CFR 186.1756 - Sodium formate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Sodium formate. 186.1756 Section 186.1756 Food and....1756 Sodium formate. (a) Sodium formate (CHNaO2, CAS Reg. No. 141-53-7) is the sodium salt of formic acid. It is produced by the reaction of carbon monoxide with sodium hydroxide. (b) The ingredient...

  5. 40 CFR 1502.10 - Recommended format.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 1502.10 Protection of Environment COUNCIL ON ENVIRONMENTAL QUALITY ENVIRONMENTAL IMPACT STATEMENT § 1502.10 Recommended format. Agencies shall use a format for environmental impact statements which will... following standard format for environmental impact statements should be followed unless the...

  6. In situ chemical stimulation of diatomite formations

    SciTech Connect

    Davis, B.W.

    1989-05-09

    A method is described of recovering hydrocarbon from a subsurface diatomite formation comprising the steps of: a. introducing an aqueous surface solution into the diatomite formation, the aqueous surface active solution comprising (i) a diatomite/oil/ water wettability improving agent, and (ii) an oil/water interfacial tension lowering agent; and b. producing oil from the diatomite formation.

  7. Congruence of Microsatellite and Mitochondrial DNA Variation in Acrobat Ants (Crematogaster Subgenus Decacrema, Formicidae: Myrmicinae) Inhabiting Macaranga (Euphorbiaceae) Myrmecophytes

    PubMed Central

    Ueda, Shouhei; Nagano, Yusuke; Kataoka, Yowsuke; Komatsu, Takashi; Itioka, Takao; Shimizu-kaya, Usun; Inui, Yoko; Itino, Takao

    2015-01-01

    A previously reported mitochondrial DNA (mtDNA) phylogeny of Crematogaster (subgenus Decacrema) ants inhabiting Macaranga myrmecophytes indicated that the partners diversified synchronously and their specific association has been maintained for 20 million years. However, the mtDNA clades did not exactly match morphological species, probably owing to introgressive hybridization among younger species. In this study, we determined the congruence between nuclear simple sequence repeat (SSR, also called microsatellite) genotyping and mtDNA phylogeny to confirm the suitability of the mtDNA phylogeny for inferring the evolutionary history of Decacrema ants. Analyses of ant samples from Lambir Hills National park, northeastern Borneo, showed overall congruence between the SSR and mtDNA groupings, indicating that mtDNA markers are useful for delimiting species, at least at the local level. We also found overall high host-plant specificity of the SSR genotypes of Decacrema ants, consistent with the specificity based on the mtDNA phylogeny. Further, we detected cryptic genetic assemblages exhibiting high specificity toward particular plant species within a single mtDNA clade. This finding, which may be evidence for rapid ecological and genetic differentiation following a host shift, is a new insight into the previously suggested long-term codiversification of Decacrema ants and Macaranga plants. PMID:25692953

  8. Congruence of microsatellite and mitochondrial DNA variation in acrobat ants (Crematogaster subgenus Decacrema, Formicidae: Myrmicinae) inhabiting Macaranga (Euphorbiaceae) myrmecophytes.

    PubMed

    Ueda, Shouhei; Nagano, Yusuke; Kataoka, Yowsuke; Komatsu, Takashi; Itioka, Takao; Shimizu-Kaya, Usun; Inui, Yoko; Itino, Takao

    2015-01-01

    A previously reported mitochondrial DNA (mtDNA) phylogeny of Crematogaster (subgenus Decacrema) ants inhabiting Macaranga myrmecophytes indicated that the partners diversified synchronously and their specific association has been maintained for 20 million years. However, the mtDNA clades did not exactly match morphological species, probably owing to introgressive hybridization among younger species. In this study, we determined the congruence between nuclear simple sequence repeat (SSR, also called microsatellite) genotyping and mtDNA phylogeny to confirm the suitability of the mtDNA phylogeny for inferring the evolutionary history of Decacrema ants. Analyses of ant samples from Lambir Hills National park, northeastern Borneo, showed overall congruence between the SSR and mtDNA groupings, indicating that mtDNA markers are useful for delimiting species, at least at the local level. We also found overall high host-plant specificity of the SSR genotypes of Decacrema ants, consistent with the specificity based on the mtDNA phylogeny. Further, we detected cryptic genetic assemblages exhibiting high specificity toward particular plant species within a single mtDNA clade. This finding, which may be evidence for rapid ecological and genetic differentiation following a host shift, is a new insight into the previously suggested long-term codiversification of Decacrema ants and Macaranga plants. PMID:25692953

  9. Underwater acrobatics by the world's largest predator: 360° rolling manoeuvres by lunge-feeding blue whales.

    PubMed

    Goldbogen, Jeremy A; Calambokidis, John; Friedlaender, Ari S; Francis, John; DeRuiter, Stacy L; Stimpert, Alison K; Falcone, Erin; Southall, Brandon L

    2013-02-23

    The extreme body size of blue whales requires a high energy intake and therefore demands efficient foraging strategies. As an obligate lunge feeder on aggregations of small zooplankton, blue whales engulf a large volume of prey-laden water in a single, rapid gulp. The efficiency of this feeding mechanism is strongly dependent on the amount of prey that can be captured during each lunge, yet food resources tend to be patchily distributed in both space and time. Here, we measured the three-dimensional kinematics and foraging behaviour of blue whales feeding on krill, using suction-cup attached multi-sensor tags. Our analyses revealed 360° rolling lunge-feeding manoeuvres that reorient the body and position the lower jaws so that a krill patch can be engulfed with the whale's body inverted. We also recorded these rolling behaviours when whales were in a searching mode in between lunges, suggesting that this behaviour also enables the whale to visually process the prey field and maximize foraging efficiency by surveying for the densest prey aggregations. These results reveal the complex manoeuvrability that is required for large rorqual whales to exploit prey patches and highlight the need to fully understand the three-dimensional interactions between predator and prey in the natural environment. PMID:23193050

  10. 77 FR 17323 - Special Conditions: XtremeAir GmbH, XA42; Acrobatic Category Aerodynamic Stability

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-26

    ...These special conditions are issued for the XtremeAir GmbH XA42 airplane. The XA42 airplane has a novel or unusual design feature associated with its static stability. This airplane can perform at the highest level of aerobatic competition. To be competitive, the aircraft was designed with positive and, at some points, neutral stability within its flight envelope. Its lateral and directional......

  11. 76 FR 80829 - Special Conditions: XtremeAir GmbH, XA42; Acrobatic Category Aerodynamic Stability

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-27

    ...This action proposes special conditions for the XtremeAir GmbH XA42 airplane. The XA42 airplane has a novel or unusual design feature associated with its static stability. This airplane can perform at the highest level of aerobatic competition. To be competitive, the aircraft was designed with positive and, at some points, neutral stability within its flight envelope. Its lateral and......

  12. Alegria! Flow in Leisure and Life Satisfaction: The Mediating Role of Event Satisfaction Using Data from an Acrobatics Show

    ERIC Educational Resources Information Center

    Chen, Lung Hung; Ye, Yun-Ci; Chen, Mei-Yen; Tung, I-Wu

    2010-01-01

    The aim of the current study was to examine the role of satisfaction-with-event as a mediator in the relations between flow and life satisfaction based on the bottom-up theory (Andrews and Withey in "Social indicators of well-being: Americans' perceptions of life quality." Plenum, New York, 1976; Lee et al. in "J Macromarketing" 22(2): 158-169,…

  13. Eyeblinks in formation of impressions.

    PubMed

    Omori, Y; Miyata, Y

    1996-10-01

    The purpose of this study was to investigate the influence of frequency of one's eyeblinks on creating a personal impression. The subjects, 102 males and 127 females, ages 15 to 60 years, rated on a 7-point semantic differential scale a rarely blinking person or a frequently blinking person described on a question-sheet. A factor analysis of the ratings yielded three factors, interpreted as Nervousness, Unfriendliness, and Lack of intelligence. The frequently blinking person was rated as more nervous and less intelligent than the rarely blinking person. Present results provided evidence that frequency of eyeblinks may play an important role on the formation of impressions. Further implications of the findings are discussed. PMID:8902035

  14. Crystal formation in furunculosis agar

    USGS Publications Warehouse

    Bullock, G.L.; Ross, A.J.

    1964-01-01

    SINCE ITS INTRODUCTION SOME MONTHS AGO, FURUNCULOSIS AGAR has been employed in the diagnosis of suspect furunculosis and also as a general purpose medium. During our work with this medium we have noticed discrete "colonies," of crystalline material, which very closely resemble microbial colonies. These crystal colonies are compact and appear on both the surface and subsurface; they occur in inoculated slants and plates incubated for long periods (2 to 3 weeks), as well as in uninoculated stored medium. As the crystal colonies could be confusing to workers using this medium, we decided to attempt to identify them and also to determine whether storage conditions and different lots of medium affect crystal formation.

  15. Chondrule formation in lightning discharges

    NASA Technical Reports Server (NTRS)

    Horanyi, M.

    1994-01-01

    Chondrules represent a significant mass fraction of primitive meteorites. These millimeter-sized glassy droplets appear to be the products of intensive transient heating events. Their size distribution, chemical and mineral composition, texture, isotope composition suggest that chondrules were produced as a result of short-duration melting followed by rapid cooling of solid precursor particles. Gas-dynamics heating, magnetic reconnection, and electrostatic discharges are thought to be the leading candidates to explain chondrule formation. In this paper we summarize our recent theoretical progress on the effects of 'lightning' in the early solar system and also report on preliminary results from our laboratory experiments. Differential settling of various sized dust particles toward the midplane of the nebula is suspected to build large-scale charge separations that episodically relax via the electric breakdown of the nebular gas. The electrostatic discharge os analogous to lightning in the Earth's atmosphere.

  16. Formation of ion damage tracks

    NASA Astrophysics Data System (ADS)

    Tombrello, T. A.; Wie, C. R.; Itoh, N.; Nakayama, T.

    1984-01-01

    A new model is proposed to explain both localized damage regions and preferential etching of damage tracks caused by the passage of energetic ions in insulators. The formation of each region of extended defects is initiated by the Auger decay of a vacancy produced in an inner electronic shell of an atom of the insulator by an incident ion. This decay produces an intense source of ionization within a small volume around the decaying atom, which causes decomposition of the material in a manner similar to that observed in pulsed laser irradiation. The resulting chemical or crystalline modification of the material is the latent track, which can be preferentially etched due to its changed structure.

  17. The Science of Galaxy Formation

    NASA Astrophysics Data System (ADS)

    Gilmore, Gerard

    2009-03-01

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

  18. Butanol formation from gaseous substrates.

    PubMed

    Dürre, Peter

    2016-03-01

    Mostly, butanol is formed as a product by saccharolytic anaerobes, employing the so-called ABE fermentation (for acetone-butanol-ethanol). However, this alcohol can also be produced from gaseous substrates such as syn(thesis) gas (major components are carbon monoxide and hydrogen) by autotrophic acetogens. In view of economic considerations, a biotechnological process based on cheap and abundant gases such as CO and CO2 as a carbon source is preferable to more expensive sugar or starch fermentation. In addition, any conflict for use of substrates that can also serve as human nutrition is avoided. Natural formation of butanol has been found with, e.g. Clostridium carboxidivorans, while metabolic engineering for butanol production was successful using, e.g. C. ljungdahlii. Production of butanol from CO2 under photoautotrophic conditions was also possible by recombinant DNA construction of a respective cyanobacterial Synechococcus sp. PCC 7942 strain. PMID:26903012

  19. Macromolecules Relevant to Stone Formation

    NASA Astrophysics Data System (ADS)

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

    2007-04-01

    Despite years of research, no single macromolecule in kidney calculi or in urine has yet been shown to fulfill a specific function in stone pathogenesis. In this paper we briefly review papers investigating the urinary excretion of individual macromolecules, their effects on calcium oxalate (CaOx) crystallization and attachment of crystals to renal epithelial cells, and the influence of lithogenic conditions on their renal expression in cultured cells and animal models. Using prothrombin fragment 1 (PTF1) and human serum albumin as examples, we show the types of patterns resulting from the binding of a fluorescently tagged protein to a specific CaOx monohydrate (COM) crystal face and its incorporation into the crystal structure. Molecular modeling is also used to illustrate how PTF1 can align with the atomic array on a COM crystal surface. We conclude that although many macromolecules are, by strict definition, relevant to stone formation, very few are probably truly influential.

  20. Dust formation by failed supernovae

    NASA Astrophysics Data System (ADS)

    Kochanek, C. S.

    2014-11-01

    We consider dust formation during the ejection of the hydrogen envelope of a red supergiant during a failed supernova (SN) creating a black hole. While the dense, slow moving ejecta are very efficient at forming dust, only the very last phases of the predicted visual transient will be obscured. The net grain production consists of Md ˜ 10- 2 M⊙ of very large grains (10-1000 μm). 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.

  1. Combuster. [low nitrogen oxide formation

    NASA Technical Reports Server (NTRS)

    Mckay, R. A. (Inventor)

    1978-01-01

    A combuster is provided for utilizing a combustible mixture containing fuel and air, to heat a load fluid such as water or air, in a manner that minimizes the formation of nitrogen oxide. The combustible mixture passes through a small diameter tube where the mixture is heated to its combustion temperature, while the load fluid flows past the outside of the tube to receive heat. The tube is of a diameter small enough that the combustible mixture cannot form a flame, and yet is not subject to wall quench, so that combustion occurs, but at a temperature less than under free flame conditions. Most of the heat required for heating the combustible mixture to its combustion temperature, is obtained from heat flow through the walls of the pipe to the mixture.

  2. Polar Cap Formation on Ganymede

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

    Since thermal migration is not an effective mechanism for water transport in the polar regions at the Galilean satellites, some other process must be responsible for the formation of Ganymede's polar caps. It is proposed that Ganymede's polar caps are the optical manifestation of a process that began with the distribution of an ice sheet over the surface of Ganymede. The combined processes of impact gardening and thermal migration led, in regions at latitudes less than 40 to 45 deg., to the burial of some fraction of this ice, the migration of some to the polar caps margins, and a depletion of free ice in the optical surface. At higher latitudes, no process was effective in removing ice from the optical surface, so the remanants of the sheet are visible today.

  3. Biofilm Formation by Cryptococcus neoformans.

    PubMed

    Martinez, Luis R; Casadevall, Arturo

    2015-06-01

    The fungus Cryptococcus neoformans possesses a polysaccharide capsule and can form biofilms on medical devices. The increasing use of ventriculoperitoneal shunts to manage intracranial hypertension associated with cryptococcal meningoencephalitis highlights the importance of investigating the biofilm-forming properties of this organism. Like other microbe-forming biofilms, C. neoformans biofilms are resistant to antimicrobial agents and host defense mechanisms, causing significant morbidity and mortality. This chapter discusses the recent advances in the understanding of cryptococcal biofilms, including the role of its polysaccharide capsule in adherence, gene expression, and quorum sensing in biofilm formation. We describe novel strategies for the prevention or eradication of cryptococcal colonization of medical prosthetic devices. Finally, we provide fresh thoughts on the diverse but interesting directions of research in this field that may result in new insights into C. neoformans biology. PMID:26185073

  4. Mud Volcanoes Formation And Occurrence

    NASA Astrophysics Data System (ADS)

    Guliyev, I. S.

    2007-12-01

    Mud volcanoes are natural phenomena, which occur throughout the globe. They are found at a greater or lesser scale in Azerbaijan, Turkmenistan, Georgia, on the Kerch and Taman peninsulas, on Sakhalin Island, in West Kuban, Italy, Romania, Iran, Pakistan, India, Burma, China, Japan, Indonesia, Malaysia, New Zealand, Mexico, Colombia, Trinidad and Tobago, Venezuela and Ecuador. Mud volcanoes are most well-developed in Eastern Azerbaijan, where more than 30% of all the volcanoes in the world are concentrated. More than 300 mud volcanoes have already been recognized here onshore or offshore, 220 of which lie within an area of 16,000 km2. Many of these mud volcanoes are particularly large (up to 400 m high). The volcanoes of the South Caspian form permanent or temporary islands, and numerous submarine banks. Many hypotheses have been developed regarding the origin of mud volcanoes. Some of those hypotheses will be examined in the present paper. Model of spontaneous excitation-decompaction (proposed by Ivanov and Guliev, 1988, 2002). It is supposed that one of major factors of the movement of sedimentary masses and formation of hydrocarbon deposits are phase transitions in sedimentary basin. At phase transitions there are abnormal changes of physical and chemical parameters of rocks. Abnormal (high and negative) pressure takes place. This process is called as excitation of the underground environment with periodicity from several tens to several hundreds, or thousand years. The relationship between mud volcanism and the generation of hydrocarbons, particularly methane, is considered to be a critical factor in mud volcano formation. At high flow rates the gas and sediment develops into a pseudo-liquid state and as flow increases the mass reaches the "so-called hover velocity" where mass transport begins. The mass of fluid moves as a quasi-uniform viscous mass through the sediment pile in a piston like manner until expelled from the surface as a "catastrophic eruption

  5. Formation and support of prominence

    NASA Technical Reports Server (NTRS)

    Forbes, T. G.

    1986-01-01

    A short introduction is given to the concepts discussed by the group on the formation and support of prominences. Only quiescent and long-lived active region prominences were considered, since transient prominence phenomena, such as sprays, surges, H alpha flare-loops, and coronal rain, are dynamically distinct from long-lived, prominences. Stable prominences (which are often referred to as filaments when seen against the disk) can be subdivided into three categories, namely active region prominences, quiescent prominences and polar crown prominences. The third category is closely related to the second since a quiescent prominence will eventually evolve into a polar crown prominence if it lasts long enough. The distinction between the first and second categories is not sharp either since intermediates exist here as well (Martin, 1973).

  6. Systems genetics of wood formation.

    PubMed

    Mizrachi, Eshchar; Myburg, Alexander A

    2016-04-01

    In woody plants, xylogenesis is an exceptionally strong carbon sink requiring robust transcriptional control and dynamic coordination of cellular and metabolic processes directing carbon allocation and partitioning into secondary cell wall biosynthesis. As a biological process, wood formation is an excellent candidate for systems modeling due to the strong correlation patterns and interconnectedness observed for transcriptional and metabolic component traits contributing to complex phenotypes such as cell wall chemistry and ultrastructure. Genetic variation in undomesticated tree populations provides abundant perturbation of systems components, adding another dimension to plant systems biology (besides spatial and temporal variation). High-throughput analysis of molecular component traits in adult trees has provided the first insights into the systems genetics of wood, an important renewable feedstock for biomaterials and bioenergy. PMID:26943939

  7. Statoconia formation in molluscan statocysts

    NASA Technical Reports Server (NTRS)

    Wiederhold, M. L.; Sheridan, C. E.; Smith, N. K.

    1986-01-01

    The gravity sensors of all molluscs phylogenetically below the cephalopods are spherical organs called statocysts. The wall of the sphere contains mechanosensory cells whose sensory cilia project into the lumen of the cyst. The lumen is filled with fluid and dense "stones", the statoconia or statoliths, which sink under the influence of gravity to load, and stimulate, those receptor cells which are at the bottom. The statoconia of Aplysia californica are shown to be calcified about a lamellar arrangement of membranes. Similar lamellar membrane arrangements are seen within the receptor cells, and their possible role in the formation of the statoconia is discussed. SEM of unfixed statoconia reveals plate-like crystallization on their surface. Elemental analysis shows a relatively high Sr content, which is of interest, since others have recently reported that Sr is required in the culture medium of several laboratory reared molluscs in order for the statoconia to develop.

  8. Polar frost formation on Ganymede

    NASA Technical Reports Server (NTRS)

    Johnson, R. E.

    1985-01-01

    Voyager photographs have shown the presence of polar frost on Ganymede, a satellite of Jupiter. A number of models have been proposed for the formation of this feature. The models are based on the transport of material from the equatorial to the polar regions. The present paper is concerned with a model regarding the origin and appearance of the Ganymede caps which does not depend on such a transport. The model is based on observations of the surficial changes produced by ion bombardment. It is pointed out that experiments on ion and electron bombardment of water ice at low temperatures have shown that these particles sputter significant quantities of water molecules. In addition, they also change the visual characteristics of the surface significantly. Ion bombardment competing with thermal reprocessing may be sufficient to explain the latitudinal differences observed on Ganymede.

  9. Foam formation in low gravity

    NASA Technical Reports Server (NTRS)

    Wessling, Francis C.; Mcmanus, Samuel P.; Matthews, John; Patel, Darayas

    1990-01-01

    An apparatus that produced the first polyurethane foam in low gravity has been described. The chemicals were mixed together in an apparatus designed for operation in low gravity. Mixing was by means of stirring the chemicals with an electric motor and propeller in a mixing chamber. The apparatus was flown on Consort 1, the first low-gravity materials payload launched by a commercial rocket launch team. The sounding rocket flight produced over 7 min of low gravity during which a polyurethane spheroidal foam of approximately 2300 cu cm was formed. Photographs of the formation of the foam during the flight show the development of the spheroidal form. This begins as a small sphere and grows to approximately a 17-cm-diam spheroid. The apparatus will be flown again on subsequent low-gravity flights.

  10. Engineering Model for Ash Formation

    1994-12-02

    Ash deposition is controlled by the impaction and sticking of individual ash particles to heat transfer surfaces. Prediction of deposition therefore requires that the important factors in this process be predictable from coal and operational parameters. Coal combustion, boiler heat transfer, ash formation, ash particle aerodynamic, and ash particle sticking models are all essential steps in this process. The model described herein addresses the prediction of ash particle size and composition distributions based upon combustionmore » conditions and coal parameters. Key features of the model include a mineral redistribution routine to invert CCSEM mineralogical data, and a mineral interaction routine that simulates the conversion of mineral matter into ash during coal burning and yields ash particle size and composition distributions.« less

  11. Heating tar sands formations while controlling pressure

    DOEpatents

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

    2010-01-12

    Methods for treating a tar sands formation are described herein. Methods may include heating at least a section of a hydrocarbon layer in the formation from a plurality of heaters located in the formation. A pressure in the majority of the section may be maintained below a fracture pressure of the formation. The pressure in the majority of the section may be reduced to a selected pressure after the average temperature reaches a temperature that is above 240.degree. C. and is at or below pyrolysis temperatures of hydrocarbons in the section. At least some hydrocarbon fluids may be produced from the formation.

  12. Bone formation in axial spondyloarthritis.

    PubMed

    Lories, Rik J; Haroon, Nigil

    2014-10-01

    The success of targeted therapies directed against tumor necrosis factor for patients with spondyloarthritis has shifted the focus of physicians and scientists towards the prevention of structural damage to the involved structures, in particular the sacroiliac joints and the spine, to avoid loss of function and disability. Structural damage to the skeleton as witnessed by radiography mainly consists of new bone formation potentially progressively leading to spine or joint ankylosis. This important long-term outcome parameter has been difficult to study, not alone because the time window for change may be long but also because human tissues with direct translational relevance are rarely available. Data from rodent models have identified growth factor signaling pathways as relevant targets. Both human and animal studies have tried to understand the link between inflammation and new bone formation. At the current moment, most evidence points towards a strong link between both but with the question still lingering about the sequence of events, disease triggers, and the interdependence of both features of disease. New discoveries such as a masterswitch T cell population that carries the IL23 receptor and the analysis of auto-antibodies directed again noggin and sclerostin are contributing to innovative insights into the pathophysiology of disease. Long-term data with tumor necrosis factor (TNF) inhibitors also suggest that some window of opportunity may exist to inhibit structural disease progression. All these data provide support for a further critical analysis of the available datasets and boost research in the field. The introduction of novel disease definitions, in particular the characterization of non-radiographic axial spondyloarthritis patients, will likely be instrumental in our further understanding of structural damage. PMID:25488783

  13. Biomineralization: mineral formation by organisms

    NASA Astrophysics Data System (ADS)

    Addadi, Lia; Weiner, Steve

    2014-09-01

    Organisms form many different types of minerals, with diverse shapes and sizes. These minerals fulfill a variety of functions. Inspired by the late H A Lowenstam, Steve Weiner and Lia Addadi have addressed many questions that relate to the mechanisms by which biological organisms produce these mineral phases and how their structures relate to their functions. Addadi and Weiner have explored the manner in which macromolecules extracted from mineralized tissues can interact with some crystal planes and not others, how these macromolecules can be occluded inside the forming crystals residing preferentially on specific crystal planes, and how they can induce one polymorph of calcium carbonate and not another to nucleate. Addadi and Weiner have also identified a novel strategy used by the sea urchin to form its smooth and convoluted mineralized skeletal elements. The strategy involves the initial production by cells of a highly disordered mineral precursor phase in vesicles, and then the export of this so-called amorphous phase to the site of skeletal formation, where it crystallizes. This strategy is now known to be used by many different invertebrate phyla, as well as by vertebrates to build bones and teeth. One of the major current research aims of the Weiner--Addadi group is to understand the biomineralization pathways whereby ions are extracted from the environment, are transported and deposited inside cells within vesicles, how these disordered phases are then transferred to the site of skeletal formation, and finally how the so-called amorphous phase crystallizes. Biology has clearly evolved unique strategies for forming crystalline minerals. Despite more than 300 years of research in this field, many challenging questions still remain unanswered.

  14. Multimap formation in visual cortex

    PubMed Central

    Jain, Rishabh; Millin, Rachel; Mel, Bartlett W.

    2015-01-01

    An extrastriate visual area such as V2 or V4 contains neurons selective for a multitude of complex shapes, all sharing a common topographic organization. Simultaneously developing multiple interdigitated maps—hereafter a “multimap”—is challenging in that neurons must compete to generate a diversity of response types locally, while cooperating with their dispersed same-type neighbors to achieve uniform visual field coverage for their response type at all orientations, scales, etc. Previously proposed map development schemes have relied on smooth spatial interaction functions to establish both topography and columnar organization, but by locally homogenizing cells' response properties, local smoothing mechanisms effectively rule out multimap formation. We found in computer simulations that the key requirements for multimap development are that neurons are enabled for plasticity only within highly active regions of cortex designated “learning eligibility regions” (LERs), but within an LER, each cell's learning rate is determined only by its activity level with no dependence on location. We show that a hybrid developmental rule that combines spatial and activity-dependent learning criteria in this way successfully produces multimaps when the input stream contains multiple distinct feature types, or in the degenerate case of a single feature type, produces a V1-like map with “salt-and-pepper” structure. Our results support the hypothesis that cortical maps containing a fine mixture of different response types, whether in monkey extrastriate cortex, mouse V1 or elsewhere in the cortex, rather than signaling a breakdown of map formation mechanisms at the fine scale, are a product of a generic cortical developmental scheme designed to map cells with a diversity of response properties across a shared topographic space. PMID:26641946

  15. Drill cuttings mount formation study

    NASA Astrophysics Data System (ADS)

    Teh, Su Yean; Koh, Hock Lye

    2014-07-01

    Oil, Gas and Energy sector has been identified as an essential driving force in the Malaysian Economic Transformation Programs (ETP). Recently confirmed discovery of many offshore oil and gas deposits in Malaysian waters has ignited new confidence in this sector. However, this has also spurred intense interest on safeguarding the health and environment of coastal waters in Malaysia from adverse impact resulting from offshore oil and gas production operation. Offshore discharge of spent drilling mud and rock cuttings is the least expensive and simplest option to dispose of large volumes of drilling wastes. But this onsite offshore disposal may have adverse environmental impacts on the water column and the seabed. It may also pose occupational health hazards to the workers living in the offshore platforms. It is therefore important to model the transport and deposition of drilling mud and rock cuttings in the sea to enable proper assessment of their adverse impacts on the environment and the workers. Further, accumulation of drill particles on the seabed may impede proper operation of pipelines on the seabed. In this paper, we present an in-house application model TUNA-PT developed to cater to local oil and gas industry needs to simulate the dispersion and mount formation of drill cuttings by offshore oil and gas exploration and production platforms. Using available data on Malaysian coastal waters, simulation analyses project a pile formation on the seabed with a maximum height of about 1 m and pile radius of around 30 to 50 m. Simulated pile heights are not sensitive to the heights of release of the cuttings as the sensitivity has been mitigated by the depth of water.

  16. Engram formation in psychiatric disorders

    PubMed Central

    Gebicke-Haerter, Peter J.

    2014-01-01

    Environmental factors substantially influence beginning and progression of mental illness, reinforcing or reducing the consequences of genetic vulnerability. Often initiated by early traumatic events, “engrams” or memories are formed that may give rise to a slow and subtle progression of psychiatric disorders. The large delay between beginning and time of onset (diagnosis) may be explained by efficient compensatory mechanisms observed in brain metabolism that use optional pathways in highly redundant molecular interactions. To this end, research has to deal with mechanisms of learning and long-term memory formation, which involves (a) epigenetic changes, (b) altered neuronal activities, and (c) changes in neuron-glia communication. On the epigenetic level, apparently DNA-methylations are more stable than histone modifications, although both closely interact. Neuronal activities basically deliver digital information, which clearly can serve as basis for memory formation (LTP). However, research in this respect has long time neglected the importance of glia. They are more actively involved in the control of neuronal activities than thought before. They can both reinforce and inhibit neuronal activities by transducing neuronal information from frequency-encoded to amplitude and frequency-modulated calcium wave patterns spreading in the glial syncytium by use of gap junctions. In this way, they serve integrative functions. In conclusion, we are dealing with two concepts of encoding information that mutually control each other and synergize: a digital (neuronal) and a wave-like (glial) computing, forming neuron-glia functional units with inbuilt feedback loops to maintain balance of excitation and inhibition. To better understand mental illness, we have to gain more insight into the dynamics of adverse environmental impact on those cellular and molecular systems. This report summarizes existing knowledge and draws some outline about further research in molecular

  17. Microfoam formation in a capillary.

    PubMed

    Kotopoulis, Spiros; Postema, Michiel

    2010-02-01

    The ultrasound-induced formation of bubble clusters may be of interest as a therapeutic means. If the clusters behave as one entity, i.e., one mega-bubble, its ultrasonic manipulation towards a boundary is straightforward and quick. If the clusters can be forced to accumulate to a microfoam, entire vessels might be blocked on purpose using an ultrasound contrast agent and a sound source. In this paper, we analyse how ultrasound contrast agent clusters are formed in a capillary and what happens to the clusters if sonication is continued, using continuous driving frequencies in the range 1-10 MHz. Furthermore, we show high-speed camera footage of microbubble clustering phenomena. We observed the following stages of microfoam formation within a dense population of microbubbles before ultrasound arrival. After the sonication started, contrast microbubbles collided, forming small clusters, owing to secondary radiation forces. These clusters coalesced within the space of a quarter of the ultrasonic wavelength, owing to primary radiation forces. The resulting microfoams translated in the direction of the ultrasound field, hitting the capillary wall, also owing to primary radiation forces. We have demonstrated that as soon as the bubble clusters are formed and as long as they are in the sound field, they behave as one entity. At our acoustic settings, it takes seconds to force the bubble clusters to positions approximately a quarter wavelength apart. It also just takes seconds to drive the clusters towards the capillary wall. Subjecting an ultrasound contrast agent of given concentration to a continuous low-amplitude signal makes it cluster to a microfoam of known position and known size, allowing for sonic manipulation. PMID:19875143

  18. Star formation in 30 Doradus

    NASA Astrophysics Data System (ADS)

    De Marchi, Guido; Paresce, F.; Sirianni, M.; Spezzi, L.; Andersen, M.; Panagia, N.; Mutchler, M.; SOC, WFC3

    2010-01-01

    We report on the preliminary results of our investigation of the properties of star formation in the 30 Doradus region, in the Large Magellanic Cloud. This study makes use of the panchromatic observations recently obtained with the Wide Field Camera 3 (WFC3) on board the HST in a number of broad- and narrow-band filters at visible and near infrared wavelengths (U, B, V, Halpha, I, J, H). The data clearly reveal the presence of considerable differential extinction across the field. We characterise and quantify this effect using both young main sequence stars and old red giants, showing that the two populations have different extinction properties, and use this information to derive a statistical reddening correction for each star in the field. We then search for pre-main sequence stars looking for objects with a strong (> 5 sigma) Halpha excess emission and find more than 1000 of them over the entire field. Comparison of their location in the H-R diagram with theoretical pre-main sequence evolutionary tracks reveals that about half of these objects have an age of 3 Myr, compatible with that of the massive stars in the field, whereas the rest have an age of 15 Myr, indicating that more than one episode of star formation has taken place in the recent past in this area. This paper is based on Early Release Science observations made by the WFC3 Scientific Oversight Committee. We are grateful to the Director of the Space Telescope Science Institute for awarding Director's Discretionary time for this programme.

  19. Gene expression during memory formation.

    PubMed

    Igaz, Lionel Muller; Bekinschtein, Pedro; Vianna, Monica M R; Izquierdo, Ivan; Medina, Jorge H

    2004-01-01

    For several decades, neuroscientists have provided many clues that point out the involvement of de novo gene expression during the formation of long-lasting forms of memory. However, information regarding the transcriptional response networks involved in memory formation has been scarce and fragmented. With the advent of genome-based technologies, combined with more classical approaches (i.e., pharmacology and biochemistry), it is now feasible to address those relevant questions--which gene products are modulated, and when that processes are necessary for the proper storage of memories--with unprecedented resolution and scale. Using one-trial inhibitory (passive) avoidance training of rats, one of the most studied tasks so far, we found two time windows of sensitivity to transcriptional and translational inhibitors infused into the hippocampus: around the time of training and 3-6 h after training. Remarkably, these periods perfectly overlap with the involvement of hippocampal cAMP/PKA (protein kinase A) signaling pathways in memory consolidation. Given the complexity of transcriptional responses in the brain, particularly those related to processing of behavioral information, it was clearly necessary to address this issue with a multi-variable, parallel-oriented approach. We used cDNA arrays to screen for candidate inhibitory avoidance learning-related genes and analyze the dynamic pattern of gene expression that emerges during memory consolidation. These include genes involved in intracellular kinase networks, synaptic function, DNA-binding and chromatin modification, transcriptional activation and repression, translation, membrane receptors, and oncogenes, among others. Our findings suggest that differential and orchestrated hippocampal gene expression is necessary in both early and late periods of long-term memory consolidation. Additionally, this kind of studies may lead to the identification and characterization of genes that are relevant for the pathogenesis

  20. Magnetic Assisted Colloidal Pattern Formation

    NASA Astrophysics Data System (ADS)

    Yang, Ye

    Pattern formation is a mysterious phenomenon occurring at all scales in nature. The beauty of the resulting structures and myriad of resulting properties occurring in naturally forming patterns have attracted great interest from scientists and engineers. One of the most convenient experimental models for studying pattern formation are colloidal particle suspensions, which can be used both to explore condensed matter phenomena and as a powerful fabrication technique for forming advanced materials. In my thesis, I have focused on the study of colloidal patterns, which can be conveniently tracked in an optical microscope yet can also be thermally equilibrated on experimentally relevant time scales, allowing for ground states and transitions between them to be studied with optical tracking algorithms. In particular, I have focused on systems that spontaneously organize due to particle-surface and particle-particle interactions, paying close attention to systems that can be dynamically adjusted with an externally applied magnetic or acoustic field. In the early stages of my doctoral studies, I developed a magnetic field manipulation technique to quantify the adhesion force between particles and surfaces. This manipulation technique is based on the magnetic dipolar interactions between colloidal particles and their "image dipoles" that appear within planar substrate. Since the particles interact with their own images, this system enables massively parallel surface force measurements (>100 measurements) in a single experiment, and allows statistical properties of particle-surface adhesion energies to be extracted as a function of loading rate. With this approach, I was able to probe sub-picoNewton surface interactions between colloidal particles and several substrates at the lowest force loading rates ever achieved. In the later stages of my doctoral studies, I focused on studying patterns formed from particle-particle interaction, which serve as an experimental model of

  1. Formation of lunar basin rings

    USGS Publications Warehouse

    Hodges, C.A.; Wilhelms, D.E.

    1978-01-01

    The origin of the multiple concentric rings that characterize lunar impact basins, and the probable depth and diameter of the transient crater have been widely debated. As an alternative to prevailing "megaterrace" hypotheses, we propose that the outer scarps or mountain rings that delineate the topographic rims of basins-the Cordilleran at Orientale, the Apennine at Imbrium, and the Altai at Nectaris-define the transient cavities, enlarged relatively little by slumping, and thus are analogous to the rim crests of craters like Copernicus; inner rings are uplifted rims of craters nested within the transient cavity. The magnitude of slumping that occurs on all scarps is insufficient to produce major inner rings from the outer. These conclusions are based largely on the observed gradational sequence in lunar central uplifts:. from simple peaks through somewhat annular clusters of peaks, peak and ring combinations and double ring basins, culminating in multiring structures that may also include peaks. In contrast, belts of slump terraces are not gradational with inner rings. Terrestrial analogs suggest two possible mechanisms for producing rings. In some cases, peaks may expand into rings as material is ejected from their cores, as apparently occurred at Gosses Bluff, Australia. A second process, differential excavation of lithologically diverse layers, has produced nested experimental craters and is, we suspect, instrumental in the formation of terrestrial ringed impact craters. Peak expansion could produce double-ring structures in homogeneous materials, but differential excavation is probably required to produce multiring and peak-in-ring configurations in large lunar impact structures. Our interpretation of the representative lunar multiring basin Orientale is consistent with formation of three rings in three layers detected seismically in part of the Moon-the Cordillera (basin-bounding) ring in the upper crust, the composite Montes Rook ring in the underlying

  2. Diet and renal stone formation.

    PubMed

    Trinchieri, A

    2013-02-01

    The relationship between diet and the formation of renal stones is demonstrated, but restrictive diets do not take into account the complexity of metabolism and the complex mechanisms that regulate the saturation and crystallization processes in the urine. The restriction of dietary calcium can reduce the urinary excretion of calcium but severe dietary restriction of calcium causes hyperoxaluria and a progressive loss of bone mineral component. Furthermore urinary calcium excretion is influenced by other nutrients than calcium as sodium, potassium, protein and refined carbohydrates. Up to 40% of the daily excretion of oxalate in the urine is from dietary source, but oxalate absorption in the intestine depends linearly on the concomitant dietary intake of calcium and is influenced by the bacterial degradation by several bacterial species of intestinal flora. A more rational approach should be based on the cumulative effects of foods and different dietary patterns on urinary saturation rather than on the effect of single nutrients. A diet based on a adequate intake of calcium (1000-1200 mg per day) and containment of animal protein and salt can decrease significantly urinary supersaturation for calcium oxalate and reduce the relative risk of stone recurrence in hypercalciuric renal stone formers. The DASH-style diet that is high in fruits and vegetables, moderate in low-fat dairy products and low in animal proteins and salt is associated with a lower relative supersaturation for calcium oxalate and a marked decrease in risk of incident stone formation. All the diets above mentioned have as a common characteristic the reduction of the potential acid load of the diet that can be correlated with a higher risk of recurrent nephrolithiasis, because the acid load of diet is inversely related to urinary citrate excretion. The restriction of protein and salt with an adequate calcium intake seem to be advisable but should be implemented with the advice to increase the intake

  3. Eye formation in the absence of retina

    PubMed Central

    Swindell, Eric C.; Liu, Chaomei; Shah, Rina; Smith, April N.; Lang, Richard A.; Jamrich, Milan

    2008-01-01

    Eye development is a complex process that involves the formation of the retina and the lens, collectively called the eyeball, as well as the formation of auxiliary eye structures such as the eyelid, lacrimal gland, cornea and conjunctiva. The developmental requirements for the formation of each individual structure are only partially understood. We have shown previously that the homeobox-containing gene Rx is a key component in eye formation, as retinal structures do not develop and retina-specific gene expression is not observed in Rx-deficient mice. In addition, Rx−/− embryos do not develop any lens structure, despite the fact that Rx is not expressed in the lens. This demonstrates that during normal mammalian development, retina-specific gene expression is necessary for lens formation. In this paper we show that lens formation can be restored in Rx-deficient embryos experimentally, by the elimination of β-catenin expression in the head surface ectoderm. This suggests that β-catenin is involved in lens specification either through Wnt signaling or through its function in cell adhesion. In contrast to lens formation, we demonstrate that the development of auxiliary eye structures does not depend on retina-specific gene expression or retinal morphogenesis. These results point to the existence of two separate developmental processes involved in the formation of the eye and its associated structures. One involved in the formation of the eyeball and the second involved in the formation of the auxiliary eye structures. PMID:18675797

  4. Dune formation under bimodal winds

    PubMed Central

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

    2009-01-01

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

  5. Cosmic vacuum and galaxy formation

    NASA Astrophysics Data System (ADS)

    Chernin, A. D.

    2006-04-01

    It is demonstrated that the protogalactic perturbations must enter the nonlinear regime before the red shift z≈ 1; otherwise they would be destroyed by the antigravity of the vacuum dark energy at the subsequent epoch of the vacuum domination. At the zrrV={M/[(8π/3)ρV]}1/3, where M is the mass of a given over-density and ρV 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.

  6. Spheromak formation studies in SSPX

    SciTech Connect

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

    2000-09-29

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

  7. Kinetically guided colloidal structure formation

    PubMed Central

    Hecht, Fabian M.; Bausch, Andreas R.

    2016-01-01

    The self-organization of colloidal particles is a promising approach to create novel structures and materials, with applications spanning from smart materials to optoelectronics to quantum computation. However, designing and producing mesoscale-sized structures remains a major challenge because at length scales of 10–100 μm equilibration times already become prohibitively long. Here, we extend the principle of rapid diffusion-limited cluster aggregation (DLCA) to a multicomponent system of spherical colloidal particles to enable the rational design and production of finite-sized anisotropic structures on the mesoscale. In stark contrast to equilibrium self-assembly techniques, kinetic traps are not avoided but exploited to control and guide mesoscopic structure formation. To this end the affinities, size, and stoichiometry of up to five different types of DNA-coated microspheres are adjusted to kinetically control a higher-order hierarchical aggregation process in time. We show that the aggregation process can be fully rationalized by considering an extended analytical DLCA model, allowing us to produce mesoscopic structures of up to 26 µm in diameter. This scale-free approach can easily be extended to any multicomponent system that allows for multiple orthogonal interactions, thus yielding a high potential of facilitating novel materials with tailored plasmonic excitation bands, scattering, biochemical, or mechanical behavior. PMID:27444018

  8. [Liquid method of electret formation].

    PubMed

    Lowkis, B; Raubuć, Z

    1983-01-01

    The work presents the results of investigations of electrets formed according to the liquid method. This method utilizes transmission of electric charge from conductive liquid to dielectric surface. Electrets were made of poliester foil "Hostaphan". Various liquids such as acetone, ethanol, Ringer solution and distilled water were used for charging. It was established that surface densities of electret charge formed by Ringer solution and acetone are about from 15 to 20 nC/cm2, whereas those formed by ethanol and distilled water from 5 to 10 nC/cm2. These electrets are characterized by big stability of charge and their survival time is about 100 years. Deelectrization of electrets in liquids that were formerly used for formation was also performed. It appeared that the survival time of the samples after deelectrization was several times longer than the survival time of electrets. The longest survival time have samples formed by ethanol and deelectrized by Ringer solution (about 10(9) years). PMID:6680180

  9. String formation beyond leading colour

    NASA Astrophysics Data System (ADS)

    Christiansen, Jesper R.; Skands, Peter Z.

    2015-08-01

    We present a new model for the hadronisation of multi-parton systems, in which colour correlations beyond leading N C are allowed to influence the formation of confining potentials (strings). The multiplet structure of SU(3) is combined with a minimisation of the string potential energy, to decide between which partons strings should form, allowing also for "baryonic" configurations (e.g., two colours can combine coherently to form an anticolour). In e + e -collisions, modifications to the leading-colour picture are small, suppressed by both colour and kinematics factors. But in pp collisions, multi-parton interactions increase the number of possible subleading connections, counteracting their naive 1/ N {/C 2} suppression. Moreover, those that reduce the overall string lengths are kinematically favoured. The model, which we have implemented in the PYTHIA 8 generator, is capable of reaching agreement not only with the important < p ⊥> ( n charged) distribution but also with measured rates (and ratios) of kaons and hyperons, in both ee and pp collisions. Nonetheless, the shape of their p ⊥ spectra remains challenging to explain.

  10. Spiral Galactic Formation and Evolution

    NASA Astrophysics Data System (ADS)

    Brekke, Stewart

    2009-05-01

    Before the period of galactic formation the uiverse consisted of a vast number of pre-formed systems consisting of two or more pre-galactic arms, the arms orbiting each other. As the orbits of the arms decayed the sides of the fore-sections of the arms tangentially collided and joined and thereby forming multi-armed spiral galaxies which began to rotate.The rotation resulted from the conversion of the orbital motion of the individual arms when joined into faster rotational motion of the newly formed galaxy. The spiral arms were maintained by the centripital force of the rapidly rotational motion of the galaxy system. As the rotational motion of the galaxy slowed down the arms of the spiral galaxy collapsed towards the body of the galaxy due to lessening of centripetal force on the arms and elliptical galaxies were formed and with further lessening of galactic rotational motion galactic disks were formed. One can see in galaxies M51, M100, NGC2336 and NGC4939 the galactic arms came from external orbit, not disks or instabilities in support of this theory. Also in support of this theory of galactic evolution is that spiral galaxies rotate faster than ellipticals or disks.

  11. Synthetic Hormones and Clot Formation.

    PubMed

    Swanepoel, Albe C; Visagie, Amcois; Pretorius, Etheresia

    2016-08-01

    Combined oral contraceptives (COCs), colloquially referred to as "the pill," have been regarded as a medical breakthrough, as they have improved the lives of countless women, from simplifying family planning to the treatment of acne, endometriosis, polycystic ovarian syndrome, and dysmenorrhea. Unfortunately, COC usage has been associated with an increased occurrence of venous thrombosis and therefore a systemic hypercoagulable state in susceptible females. Here we discuss the health risks of COC usage and use viscoelastic and morphological techniques to investigate the effect of different COC constituents on clot formation, particularly fibrin network packaging and whole blood viscoelasticity. Viscoelastic properties of whole blood showed gender-specific changes while morphological alterations were person-specific, regardless of gender. Using scanning electron microscopy and thromboelastography provides great insight regarding fibrin packaging and the development of a hypercoagulable state in high-risk individuals. We proposed a three-step approach where (1) an individual's coagulation profile baseline is determined, after which (2) the "ideal" combination of constituents is prescribed, and (3) the coagulation profile of the individual is monitored to assess possible risk of thrombosis. Only in following such an individualized patient-oriented approach will we be able to avoid the many health issues due to COC usage in susceptible females. PMID:27515365

  12. Pattern Formation in Excitable Media

    NASA Astrophysics Data System (ADS)

    Reynolds, William Nash

    1992-01-01

    The phenomenon of excitability is observed in a wide variety of physical and biological systems. In this work, spatially extended excitable systems are examined from several different perspectives. First, a pedagogical introduction is used to motivate the derivation of the dynamics of one dimensional excitable pulses. In the second part, coupled map techniques for numerical simulation of excitable media and other interfacial systems are described. Examples are given for both excitable media and crystal growth. The third chapter addresses the phenomenon of spiral formation in excitable media. Exact rotating solutions are found for a class of models of excitable media. The solutions consist of two regions: an outer region, consisting of the spiral proper, which exhibits a singularity at its tip, and the core region, obtained by rescaling space in the vicinity of the tip. The tip singularity is resolved in the core region, leading to a consistent solution in all of space. The stability of both the spiral and the core is investigated, with the result that the spiral is found to be stable, and the core unstable. Finally, the stability of excitable waves of the chemical cAMP traveling over aggregating colonies of the slime mold Dictyostelium discoideum is examined by coupling the excitable dynamics of the cAMP signalling system to a simple model of chemotaxis, with result that cellular motion is found to destabilize the waves, causing the initially uniform field of cells to break up into streams.

  13. Collagen fibril formation during development

    SciTech Connect

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

    1987-05-01

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

  14. Pattern formation in centrosome assembly.

    PubMed

    Mahen, Robert; Venkitaraman, Ashok R

    2012-02-01

    A striking but poorly explained feature of cell division is the ability to assemble and maintain organelles not bounded by membranes, from freely diffusing components in the cytosol. This process is driven by information transfer across biological scales such that interactions at the molecular scale allow pattern formation at the scale of the organelle. One important example of such an organelle is the centrosome, which is the main microtubule organising centre in the cell. Centrosomes consist of two centrioles surrounded by a cloud of proteins termed the pericentriolar material (PCM). Profound structural and proteomic transitions occur in the centrosome during specific cell cycle stages, underlying events such as centrosome maturation during mitosis, in which the PCM increases in size and microtubule nucleating capacity. Here we use recent insights into the spatio-temporal behaviour of key regulators of centrosomal maturation, including Polo-like kinase 1, CDK5RAP2 and Aurora-A, to propose a model for the assembly and maintenance of the PCM through the mobility and local interactions of its constituent proteins. We argue that PCM structure emerges as a pattern from decentralised self-organisation through a reaction-diffusion mechanism, with or without an underlying template, rather than being assembled from a central structural template alone. Self-organisation of this kind may have broad implications for the maintenance of mitotic structures, which, like the centrosome, exist stably as supramolecular assemblies on the micron scale, based on molecular interactions at the nanometer scale. PMID:22245706

  15. Stages of neuronal network formation

    NASA Astrophysics Data System (ADS)

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

    2013-02-01

    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.

  16. String formatting considered harmful for novice programmers

    NASA Astrophysics Data System (ADS)

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

    2010-09-01

    In Java, System.out.printf and String.format consume a specialised kind of string commonly known as a format string. In our study of first-year students at the Ateneo de Manila University, we discovered that format strings present a substantial challenge for novice programmers. Focusing on their first laboratory we found that 8% of all the compilation errors and 100% of the exceptional, run-time behaviour they encountered were due to the improper construction of format strings. Format strings are a language unto themselves embedded within Java, and they are difficult for novice programmers to master when learning to program. In this article, we present exemplars of students' problematic interactions with the Java compiler and run-time environment when dealing with format strings, discuss these interactions, and recommend possible instructional interventions based on our observations.

  17. Common Data Format (CDF) to store images

    NASA Technical Reports Server (NTRS)

    Shreve, Loy W., II

    1988-01-01

    The original goal of this study was to allow free interchange of images between the HGS and other analytical tools available to NASA. Originally conceived as a collection of individual computer programs that could individually convert any format image to any other format and transfer images via several routes, NASA elected to adopt a Common Data Format (CDF) to store images. This allowed the storage of all images in one format on the NASA EADS. Most of the individual programs were then combined and placed in a user friendly menu-driven system that allows free interchange of image formats within EADS (Sun Workstation), HGS, and Omnicon systems. Additional software and hardware was supplied that allows physical transfer of the formatted images throughout these systems and to external systems.

  18. Formation temperatures of thermogenic and biogenic methane

    USGS Publications Warehouse

    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

    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.

  19. Autonomous Formations of Multi-Agent Systems

    NASA Technical Reports Server (NTRS)

    Dhali, Sanjana; Joshi, Suresh M.

    2013-01-01

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

  20. Floating insulated conductors for heating subsurface formations

    SciTech Connect

    Burns, David; Goodwin, Charles R.

    2014-07-29

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