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1

A virtual petrological microscope for teaching and outreach  

NASA Astrophysics Data System (ADS)

Learning to use microscopes for geoscience or life science applications is a crucial part of the practical training offered in many science degrees, but the opportunities to study are often constrained by available laboratory space and time, and sometimes constrained by the number of high quality microscopes available. The alternative, although not replacing physical microscopes, offers the opportunity for enhancement and enrichment of laboratory experience in geoscience. An on-line microscope can also be used to engage the public with access to rare rocks such as meteorites and lunar samples. The focus of petrological microscope study in higher education is not primarily related to learning facts but is concerned with learning how to discriminate and classify within the paradigms of the discipline. In this case, the recognition and measurement of key features in rock samples in hand specimen and thin section. Whilst undertaking the practical exercise of recognition and naming of rock samples students are really being required to develop an understanding of the rock cycle as a model representing the relationship between rock categories and the process of their formation. The problems of teaching with complex visual materials, in effect of teaching learners 'how to see' from the scientific perspective of a particular discipline, are quite general. It could reasonably be expected that lessons learnt from the implementation and detailed evaluation of the proposed web-based system will generalise to many other topics in science education. Thus we focussed on the thin section images rather than reproducing a system that resembled a physical microscope. The virtual petrological microscope developed for a course at the Open University UK enables student acquisition of skills such as mineral and rock recognition using a browser window to explore thin sections of rocks as if they were using a laboratory microscope. The microscope allows students to pan around the thin sections (held as 1GB files on a remote server); zoom in and out, change from plane polarised light to cross polarised light conditions, and study the changing mineral pleochroism and birefringence in rotating view 'hot spots'. The microscope also includes tools such as hyper-linked descriptive teaching text, labels on the slide, XY coordinates and measurement tools. The fully developed system is for individual users each accessing the slides via a browser window, but we are also developing mobile version and exploring a shared version which will allow students and tutors to collaborate at distance.

Kelley, Simon P.; Whalley, Peter; Tindle, Andrew G.; Anand, Mahesh

2010-05-01

2

A virtual petrological microscope for teaching and outreach  

Microsoft Academic Search

Learning to use microscopes for geoscience or life science applications is a crucial part of the practical training offered in many science degrees, but the opportunities to study are often constrained by available laboratory space and time, and sometimes constrained by the number of high quality microscopes available. The alternative, although not replacing physical microscopes, offers the opportunity for enhancement

Simon P. Kelley; Peter Whalley; Andrew G. Tindle; Mahesh Anand

2010-01-01

3

Virtual Microscope for Earth Sciences  

NSDL National Science Digital Library

The Virtual Microscope was developed for undergraduate teaching of petrology and geoscience at the Open University in the United Kingdom, allowing students to explore rock hand specimens and thin sections in a browser window. Collections include petrographic images of terrestrial, extraterrestrial and rare rock collections.

Kelley, Simon; Tindle, Andy; Mahesh, And A.; University, Open

4

Virtual petrological microscopy: web 2.0 technology for learning microscopy skills outside the laboratory  

Microsoft Academic Search

Learning to use microscopes for geoscience or life science applications is a crucial part of the practical training offered in many science degrees, but the opportunities to study are often constrained by available laboratory space and time, and sometimes constrained by the number of high quality microscopes available. We will demonstrate a new based virtual petrological microscope which offers the

S. P. Kelley; P. Whalley; A. Tindle

2009-01-01

5

Virtual Microscope: Training  

NSDL National Science Digital Library

This web page, part of the Virtual Microscope Project, features interactive animations that illustrate the basics of imaging in the Scanning Electron Microscope (SEM), the Fluorescence Light Microscope (LM), and the Atomic Force Microscope (AFM). Also included are videos demonstrating how to prepare samples for each type of microscope. Don't miss the interviews with scientists who discuss career paths that utilize microscopy in both the public and private sectors. The Virtual Microscope provides cost-free simulated scientific instrumentation for students and researchers worldwide as part of NASA's Virtual Laboratory initiative. This site supports and shares data from all three instruments: SEM, LM, and AFM. Automated data capture software is shared with users via a Java application that provides a simulation of the group's actual microscope interfaces. The magnification controls allow the user to explore any point of interest on the sample and provides access to a robust set of specimen annotation tools.

2013-02-11

6

Virtual Compound Microscope  

NSDL National Science Digital Library

Virtual Microscopy is a very handy online tool to learn how to use a microscope. The creator developed this tool in response to student frustration in learning how to use microscopes. The virtual scope has all the same controls found on the real unit and the user can learn the parts of the microscope as well as how to adjust the different objectives, course and fine focus, and make light adjustments with the iris diaphragm. Of particular interest is the fact that the simulation shows actual microscope specimens, like onion root tip, so students can see what mitotic figures look like under the microscope without having to be expert users. Of course, a simulation does not take the place of using the actual microscope but can certainly shorten the time that it takes to learn how to use one, and lessen the amount of frustration for both student and teacher.

Ketcham, Robert; Kinney, Becky

2012-11-13

7

Virtual pinhole confocal microscope  

SciTech Connect

Scanned confocal microscopes enhance imaging capabilities, providing improved contrast and image resolution in 3-D, but existing systems have significant technical shortcomings and are expensive. Researchers at Los Alamos National Laboratory have developed a novel approach--virtual pinhole confocal microscopy--that uses state of the art illumination, detection, and data processing technologies to produce an imager with a number of advantages: reduced cost, faster imaging, improved efficiency and sensitivity, improved reliability and much greater flexibility. Work at Los Alamos demonstrated proof of principle; prototype hardware and software have been used to demonstrate technical feasibility of several implementation strategies. The system uses high performance illumination, patterned in time and space. The authors have built functional confocal imagers using video display technologies (LCD or DLP) and novel scanner based on a micro-lens array. They have developed a prototype system for high performance data acquisition and processing, designed to support realtime confocal imaging. They have developed algorithms to reconstruct confocal images from a time series of spatially sub-sampled images; software development remains an area of active development. These advances allow the collection of high quality confocal images (in fluorescence, reflectance and transmission modes) with equipment that can inexpensively retrofit to existing microscopes. Planned future extensions to these technologies will significantly enhance capabilities for microscopic imaging in a variety of applications, including confocal endoscopy, and confocal spectral imaging.

George, J.S.; Rector, D.M.; Ranken, D.M. [Los Alamos National Lab., NM (United States). Biophysics Group; Peterson, B. [SciLearn Inc. (United States); Kesteron, J. [VayTech Inc. (United States)

1999-06-01

8

Virtual Microscope: Light Microscopy Basics  

NSDL National Science Digital Library

This animated tutorial illustrates the basics of light microscopy. It opens with a brief introduction to light refraction and interference. Next, the tutorial explores light microscope anatomy and contrast methods -- including stain, darkfield, and polarized contrast. Finally, it discusses the field of fluorescent light microscopy. This resource is part of the Virtual Microscope project, which provides cost-free simulated scientific instrumentation for students and researchers worldwide as part of NASA's Virtual Laboratory initiative. See Related Materials for links to additional animated tutorials on Atomic Force Microscopy and Scanning Electron Microscopy.

2013-02-11

9

Virtual petrological microscopy: web 2.0 technology for learning microscopy skills outside the laboratory  

NASA Astrophysics Data System (ADS)

Learning to use microscopes for geoscience or life science applications is a crucial part of the practical training offered in many science degrees, but the opportunities to study are often constrained by available laboratory space and time, and sometimes constrained by the number of high quality microscopes available. We will demonstrate a new based virtual petrological microscope which offers the opportunity for enhancement and enrichment of laboratory experience in geoscience. The focus of petrological microscope study is not primarily related to learning facts but is concerned with learning how to discriminate and classify within the paradigms of the discipline. In this case, the recognition and measurement of key features in rock samples in hand specimen and thin section. Whilst undertaking the practical exercise of recognition and naming of rock samples students are really being required to develop an understanding of the rock cycle as a model representing the relationship between rock categories and the process of their formation. The problems of teaching with complex visual materials, in effect of teaching learners 'how to see' from the scientific perspective of a particular discipline, are quite general. It could reasonably be expected that lessons learnt from the implementation and detailed evaluation of the proposed web-based system will generalise to many other topics in science education. Thus we focussed on the thin section images rather than reproducing a system that resembled a physical microscope. The virtual petrological microscope developed for a course at the Open University UK enables student acquisition of skills such as mineral and rock recognition using a browser window to explore thin sections of rocks as if they were using a laboratory microscope. The microscope allows students to pan around the thin sections (held as 1GB files on a remote server); zoom in and out, change from plane polarised light to cross polarised light conditions, and study the changing mineral pleochroism and birefringence in rotating view 'hot spots'. The microscope also includes tools such as hyper-linked descriptive teaching text, labels on the slide, XY coordinates and measurement tools. The fully developed system is for individual users each accessing the slides via a browser window, but we are also developing mobile version and exploring a shared version which will allow students and tutors to collaborate at distance.

Kelley, S. P.; Whalley, P.; Tindle, A.

2009-12-01

10

Virtual Microscope: Scanning Probe Microscopy Basics  

NSDL National Science Digital Library

This animated tutorial explores the basics of scanning probe microscopy (SPM), a branch of microscopy that forms images using a tiny physical probe to scan specimens. The advantage of SPM is that it can produce high resolution images of nanoscale samples and does not require a partial vacuum. This tutorial provides beginners with a very clear picture of how the probe tip interacts with a sample surface to produce 3-dimensional data about topography. The tutorial covers scanning tunneling, contact mode, and tapping mode. For additional background information on probe microscopy, we recommend: Introduction to AFM. This resource is part of the Virtual Microscope project, which provides cost-free simulated scientific instrumentation for students and researchers worldwide as part of NASA's Virtual Laboratory initiative. See Related Materials for links to additional animated tutorials on Atomic Force Microscopy and Scanning Electron Microscopy.

2013-02-11

11

Digital dynamic telepathology--the Virtual Microscope.  

PubMed Central

The Virtual Microscope is being designed as an integrated computer hardware and software system that generates a highly realistic digital simulation of analog, mechanical light microscopy. We present our work over the past year in meeting the challenges in building such a system. The enhancements we made are discussed, as well as the planned future improvements. Performance results are provided showing the system scales well, so that many users can be adequately serviced by an appropriately configured data server. Images Figure 1 Figure 3 Figure 4

Afework, A.; Beynon, M. D.; Bustamante, F.; Cho, S.; Demarzo, A.; Ferreira, R.; Miller, R.; Silberman, M.; Saltz, J.; Sussman, A.; Tsang, H.

1998-01-01

12

Space Eyeful: A Virtual Microscope for Extraterrestrial Samples  

NASA Astrophysics Data System (ADS)

In this contribution we describe the latest developments in producing a library of virtual microscope images of a range of extraterrestrial samples for public engagement with planetary and space sciences.

Anand, M.; Pearson, V. K.; Tindle, A. G.; Kelley, S. P.; Koeberl, C.; Smith, C. L.; Whalley, P. C.

2012-03-01

13

Virtual Environment for Manipulating Microscopic Particles with Optical Tweezers.  

National Technical Information Service (NTIS)

In this paper, virtual reality techniques are used to define an intuitive interface to a nanoscale manipulation device. This device utilizes optical methods to focus laser light to trap and reposition nano-to-microscopic particles. The underlying physics ...

Y. G. Lee K. W. Lyons T. W. LeBrun

2003-01-01

14

An array microscope for ultrarapid virtual slide processing and telepathology. Design, fabrication, and validation study  

Microsoft Academic Search

This paper describes the design and fabrication of a novel array microscope for the first ultrarapid virtual slide processor (DMetrix DX-40 digital slide scanner). The array microscope optics consists of a stack of three 80-element 10 x 8-lenslet arrays, constituting a “lenslet array ensemble.” The lenslet array ensemble is positioned over a glass slide. Uniquely shaped lenses in each of

Ronald S. Weinstein; Michael R. Descour; Chen Liang; Gail Barker; Katherine M. Scott; Lynne Richter; Elizabeth A. Krupinski; Achyut K. Bhattacharyya; John R. Davis; Anna R. Graham; Margaret Rennels; William C. Russum; James F. Goodall; Pixuan Zhou; Artur G. Olszak; Bruce H. Williams; James C. Wyant; Peter H. Bartels

2004-01-01

15

Microscope light dimmer for biomedical image enhancement with virtual instrumentation  

Microsoft Academic Search

This paper focuses on high speed video acquisition system designing for biomedical image enhancement. The paper gives information about microscope dimmer using in image analysis. Due to fast digital camera, system contains intelligent illumination dimming hardware automatically regulated through measurement card. Regulating parameter for dimmer (PWM duty cycle) is computed from image features, histogram distribution and intensity relations. Dimming helps

L. Hargas?; D. Koniar; M. Hrianka; S. S?tofan

2010-01-01

16

Automatic Camera-Based Microscope Calibration for a Telemicromanipulation System Using a Virtual Pattern  

Microsoft Academic Search

In the context of virtualized-reality-based tele- micromanipulation, this paper presents a visual calibration technique for an optical microscope coupled to a CCD camera. The accuracy and flexibility of the proposed automatic virtu al calibration method, based on Parallel Single-Plane properties, are outlined. In contrast to standard approaches, a 3D virtual calibration pattern is constructed using the micromanipulator tip with subpixel-order

Mehdi Ammi; Vincent Frand Antoine Ferreira; Antoine Ferreira

2009-01-01

17

Enhancing Learning Objectives by Use of Simple Virtual Microscopic Slides in Cellular Physiology and Histology: Impact and Attitudes  

ERIC Educational Resources Information Center

|The impact and perception of students on the use of a simple, low technology-driven version of a virtual microscope in teaching and assessments in cellular physiology and histology were studied. Its impact on the time and resources of the faculty were also assessed. Simple virtual slides and conventional microscopes were used to conduct the same…

Anyanwu, Godson Emeka; Agu, Augustine Uchechukwu; Anyaehie, Ugochukwu Bond

2012-01-01

18

Sedimentary petrology  

SciTech Connect

This is an introductory book to sedimentary petrology and covers the origin, occurrence, mineral composition and texture of sedimentary rocks. The description and interpretation of sedimentary structures, environments and facies are briefly discussed. Chapters cover: the occurrence of sedimentary rocks, formation of sediment, mudrock, conglomerates and sandstones, limestones dolomites, evaporites, cherts, iron-rich, rocks, phosphorites, coal, development of research project and the practice of sedimentary petrology. One chapter has been abstracted separately.

Blatt, H.

1982-01-01

19

Petrology Home  

NSDL National Science Digital Library

This site is a clearinghouse for a variety of educational and supporting materials for teaching igneous and metamorphic petrology. Some features of the site are a collection of classroom and laboratory activities, teaching materials such as lecture notes and Power Point presentations, a database of geochemical instruments available for use at various institutions, a collection of petrology syllabi, and email list discussion groups. These collections reflect the contributions of faculty members from across the country, and will continue to grow as new materials and tools are developed.

20

Enhancing learning objectives by use of simple virtual microscopic slides in cellular physiology and histology: impact and attitudes  

NSDL National Science Digital Library

The impact and perception of students on the use of a simple, low technology-driven version of a virtual microscope in teaching and assessments in cellular physiology and histology were studied. Its impact on the time and resources of the faculty were also assessed. Simple virtual slides and conventional microscopes were used to conduct the same examinations for the same students. Students performed significantly better in the examination with the virtual slide and also showed a significantly higher preference for virtual slides. The time and cost implications of conducting examinations using the simple virtual slides were reduced by >1,400%. The results reemphasize the need for the design and adoption of simple sustainable technological innovations in developing countries to bridge gaps in purposeful learning environments.

Augustine Uchechukwu Agu (University of Nigeria)

2012-06-01

21

A Digital Approach to Learning Petrology  

NASA Astrophysics Data System (ADS)

In the undergraduate igneous and metamorphic petrology course at Northern Arizona University, we are employing petrographic microscopes equipped with relatively inexpensive ( $200) digital cameras that are linked to pen-tablet computers. The camera-tablet systems can assist student learning in a variety of ways. Images provided by the tablet computers can be used for helping students filter the visually complex specimens they examine. Instructors and students can simultaneously view the same petrographic features captured by the cameras and exchange information about them by pointing to salient features using the tablet pen. These images can become part of a virtual mineral/rock/texture portfolio tailored to individual student's needs. Captured digital illustrations can be annotated with digital ink or computer graphics tools; this activity emulates essential features of more traditional line drawings (visualizing an appropriate feature and selecting a representative image of it, internalizing the feature through studying and annotating it) while minimizing the frustration that many students feel about drawing. In these ways, we aim to help a student progress more efficiently from novice to expert. A number of our petrology laboratory exercises involve use of the camera-tablet systems for collaborative learning. Observational responsibilities are distributed among individual members of teams in order to increase interdependence and accountability, and to encourage efficiency. Annotated digital images are used to share students' findings and arrive at an understanding of an entire rock suite. This interdependence increases the individual's sense of responsibility for their work, and reporting out encourages students to practice use of technical vocabulary and to defend their observations. Pre- and post-course student interest in the camera-tablet systems has been assessed. In a post-course survey, the majority of students reported that, if available, they would use camera-tablet systems to capture microscope images (77%) and to make notes on images (71%). An informal focus group recommended introducing the cameras as soon as possible and having them available for making personal mineralogy/petrology portfolios. Because the stakes are perceived as high, use of the camera-tablet systems for peer-peer learning has been progressively modified to bolster student confidence in their collaborative efforts.

Reid, M. R.

2011-12-01

22

Petrology and plate tectonics  

Microsoft Academic Search

Petrology played an important role in the formulation of plate tectonics and early plate tectonic interpretations of the geologic past. In the last few years widespread interest in plate tectonics and progress in plate tectonic interpretations have begun to give petrology various feedback effects.In the period 1971–1974 there were two symposiums intended particularly to connect petrology with plate tectonics [Wyllie,

Akiho Miyashiro

1975-01-01

23

Modern Igneous Petrology  

Microsoft Academic Search

Mohan K. Sood prefaces Modern Igneous Petrology by stating that his objective is to facilitate the understanding of the application of phase equilibrium data to the crystallization and evolution of magmas. He states that the book may be valuable as either a reference or source text or as a text for courses in igneous petrology for undergraduate and graduate students.

Richard F. Wendlandt

1982-01-01

24

Virtualization  

NASA Astrophysics Data System (ADS)

The main aim of the research was to get the knowledge of present trends and technologies used in it field. Virtualization Allows multiple applications to run in isolation within virtual machines on the same physical machine. Virtualization provides direct access to the hardware resources to give you much greater performance than software emulation. VMware provides hardware virtualization that presents a complete x86 platform to the virtual machine. By doing this project we get an opportunity to learn about an emerging field of IT Sector. They also gave us the details of project like 'Storage Vmmotioní on which HP is currently working.

Garg, Vikas

2012-11-01

25

The nanomanipulator: a virtual-reality interface for a scanning tunneling microscope  

Microsoft Academic Search

We present an atomic-scale teleoperation system that uses a head-mounted display and force-feedback manipulator arm for a user interface and a Scanning Tunneling Microscope (STM) as a sensor and effector. The system approximates presence at the atomic scale, placing the scientist on the surface, in control, while the experiment is happening. A scientist using the Nanomanipulator can view incoming STM

Russell M. Taylor II; Warren Robinett; Vernon L. Chi; Frederick P. Brooks Jr.; William V. Wright; R. Stanley Williams; Erik J. Snyder

1993-01-01

26

Irreversible thermodynamics in petrology  

SciTech Connect

The formulation of reaction rates and transport rates from the point of view of entropy production can help elucidate petrologic processes. The theory of irreversible thermodynamics relates fluxes of heat or mass linearly to thermodynamic forces (temperature gradients or chemical potential gradients) near equilibrium. A consequence of the general theory of irreversible thermodynamics is that each flux may be influenced by any of the thermodynamic forces. This type of coupling leads to such effects as thermal diffusion, the Soret effect, and uphill diffusion. The theory, however, constrains the number and size of the coupling phenomenological coefficients. Estimates of the coupling phenomenological coefficients enable a calculation of the importance of these coupling effects. The linear theory of irreversible thermodynamics relates the rates of reactions to the free energy difference of the reaction. This relation can be used along with experimental data to obtain the individual rates of reactions in petrology. The behavior of systems far from equilibrium is shown to be different from that near equilibrium. In particular, the formation of spatial patterns so common in petrology, is intimately related to the action of a system, when far from equilibrium. The analysis of Liesegang type models as well as the spatial patterns arising from autocatalytic effects can provide useful insights into the formation of differentiated layering in petrology. (JMT)

Fisher, G.W.; Lasaga, A.C.

1981-01-01

27

Virtual Scanning Tunneling Microscope: Modeling Interlayer Tunneling Between Two-Dimensional Electron Systems in the Ballistic Regime  

NASA Astrophysics Data System (ADS)

We study a theoretical model for the virtual scanning tunneling microscope (VSTM), which is a proposal to use interlayer tunneling in a bi-layer system as a way to probe two-dimensional electron systems (2DES) in semiconductor heterostructures. We model the bi-layer in the presence of weak tunneling between the layers using an analog of the spin-boson model. Previously, such a system was modeled in the diffusive regime by Levitov and Shytov [1], and they predicted a zero-bias anomaly, where the tunneling conductance vanishes singularly near zero-bias as a result of Coulomb blocking. Motivated by the availability of high mobility samples and the goal of using VSTM to probe the physics of clean 2DES dominated by interactions, we focus on tunneling in the ballistic regime. We find the absence of a zero-bias anomaly due to extremely efficient screening in the ballistic regime. We discuss the implications of our results on ongoing experimental efforts. [1] S. Levitov and A.V. Shytov. JETP Lett. 66, 214 (1997).

Luna, Katherine; Kim, Eun-Ah; Oreto, Paul; Kivelson, Steven

2008-03-01

28

The Poster: A Petrologic Exercise For The Resource-Challenged  

Microsoft Academic Search

The scientific poster is a common format for transmitting information and can be used as a petrologic exercise that may be particularly beneficial for those programs with limited resources. For example, the Saint Norbert College geology program was founded in 1987 and a traditional geology major established in 1994. We have high quality petrographic microscopes and excellent on-campus computing resources

T. P. Flood

2003-01-01

29

Modern Igneous Petrology  

NASA Astrophysics Data System (ADS)

Mohan K. Sood prefaces Modern Igneous Petrology by stating that his objective is to facilitate the understanding of the application of phase equilibrium data to the crystallization and evolution of magmas. He states that the book may be valuable as either a reference or source text or as a text for courses in igneous petrology for undergraduate and graduate students. A review of recent literature and extensive references are promised the reader.There are eight chapters in the book. The presentation is theme-oriented and progresses from discussion of phase equilibrium in simple binary systems to those in complex synthetic and natural systems. The Introduction is intended to be ‘an overview of the igneous process and the state of the art of experimental petrology.’ Chapters 2 and 3, comprising in excess of one half of the book in extent, detail anhydrous silicate systems at 1-atm bearing on mafic magmas and residual alkaline magmas, respectively. The following four chapters deal in a perfunctory manner with silicate systems containing volatiles, volatile solubilities in silicate melts, melting relations of rocks, and the genesis of magmas. Chapter 8 summarizes the conclusions.

Wendlandt, Richard F.

30

Caltech: Experimental Petrology  

NSDL National Science Digital Library

This Caltech website discusses the work of the Ed Stolper, Peter Wyllie, George Rossman, and Paul Asimow groups in the Geological and Planetary Sciences Department. Under Paul Asimow's link, educators and students can find tutorials and applets dealing with phase equilibria. Edward Stolper provides illustrations and descriptions of his current research which includes experimental and theoretical studies of mantle melting and analyses of oxygen isotope ratios of ocean island volcanoes. George Rossman offers information on his many mineralogy research projects. The website features links to the Hawaii Scientific Drilling Project, the Experimental Petrology Facilities, and the Mineral Spectroscopy Homepage. Researchers can find lists of publications and information on conferences.

31

Lunar Global Petrologic Variations  

NASA Astrophysics Data System (ADS)

An initial attempt at producing petrologic province maps of the lunar highlands combined orbital and sample geochemical data in variation diagrams.Three different variation diagrams were produced: Mg* (= 100 Mg/Mg+Fe) vs. [(Th/Ti)c, Al vs. Mg*/(Th/Ti)c, and Fe vs. (Th/Ti)c. ([Th/Ti]c is the ratio of Th to Ti, normalized to the chrondritic ratio for these elements.] Later work applied a ternary diagram approach to look at global lunar petrologic variations. This work used the Fe-(Th/Ti)c technique as this had the most spatial coverage with the available data and also appeared to be adequate at distinguishing between different rock types. In the ternary diagram, the apexes were assigned the average Fe and (Th/Ti), values of ferroan anorthosite, mare basalt, and KREEP rocks. Each apex was assigned a primary color while the center of the triangle was represented by gray. Each point on the lunar surface, covered by the Apollo geochemical instruments, was then assigned a color depending on where in the ternary their composition placed them. The resultant petrologic classification map shows how the petrologic units vary spatially. The main results from this work were as follows: (1) The highlands contain large areas of relatively pure ferroan anorthosite; (2) KREEP/Mg suite rocks represent a small percentage of the upper lunar crust; (3) farside outcrops of KREEP/ Mg suite rocks are associated with areas of crustal thinning, particularly on the floor of South Pole Aitken Basin; (4) the average composition of the highlands is richer in Fe than ferroan anorthosite, which supports the magma ocean hypothesis of crystal formation; and (5) regions of the eastern limb and farside highlands are relatively more mafic than average highlands. These areas have a high density of dark halo craters, supporting the idea that mare volcanism occurred in this region before the end of the heavy bombardment. This earlier work utilized the Apollo gamma and X-ray orbital datasets. These data provided limited coverage of the lunar surface (mostly confined to the equatorial latitudes). The gamma ray instrument covered approximately 19% of the lunar surface while the X-ray only covered 9%. With the Clementine and Lunar Prospector datasets, we now have global maps of Fe, Ti, and Th. Apart from global coverage, another important advantage of the new datasets is higher spatial resolution. The resolution of the Apollo instruments was 15 km for the X-ray and 100 km for the gamma ray. The Fe and Ti maps are derived from the full-resolution Clementine UV-VIS data, i.e., about 250 m/pixel. The resolution of the Th data, obtained by Lunar Prospector's neutron spectrometer, is currently about 150 km, but will be available in the future with a spatial resolution of 60 km. The other improvement provided by the recent lunar missions is the error associated with the data. The errors associated with the Fe, Ti, and Th values obtained by Apollo were 10-25 wt%. The error of the Clementine-derived Fe and Ti values is about 1% while the Th data have an error of about 1 ppm. We intend to investigate the petrologic variations on the Moon at a global scale using the new Clementine and Lunar Prospector elemental maps for Fe, Ti, and Th. We shall use the technique described in Davis and Spudis. An initial study has been undertaken that looks at some regions that were covered by the Apollo geochemistry data. Two mare regions, one in Imbrium and the other in Procellarum, match well with the results using the Apollo data. The highland terrain appears problematic. The calibration of the Th data is based on the assumption of a constant background. This is a valid assumption where Th counts are well above background limits, but as count rates decrease variations in Th concentration are more sensitive to background fluctuations. Eventually we will circumvent this problem by using the lower-altitude (i.e., higher resolution) Prospector data and a calibration derived from deconvolution of the gamma ray spectra with proper attention to background variations. The Th/Ti vs. Fe technique p

Bussey, D. B. J.; Spudis, P. D.; Gillis, J. J.

1999-01-01

32

Petrology at Princeton  

NASA Astrophysics Data System (ADS)

Igneous and Metamorphic Petrology at Princeton has evolved from a course f or junior or senior majors to a course that targets sophomores who might major in geology. The prerequisite is one prior course in geology. The course is constructed around a one-week series of field exercises in the Rio Grand rift of New Mexico. These are taken during our fall break. During the field exercises they collect metamorphic or volcanic rocks that form the basis of a project that they work on in the second half of the semester. They make thin sections of their rocks, learn some microscopy and mineralogy as they examine them, and prepare a final paper with the structure of a research article. The students give oral reports in an "AGU like" session. Part of their grade is based on their questioning of their peers. Prior to the one-week trip, the students are taken on half or full-day field trips to central Atlantic rift features in the vicinity of Princeton. These trips and related labs prepare them for the trip to New Mexico. They must keep a notebook in which they record their field observations. The notebooks for the one-week trip are evaluated and the grade is a significant fraction of the final grade. This course began as an experiment, which was driven by a need to increase the number of majors in Geosciences. The course works best for class sizes of 6 to 10; one or two do not continue in geology, and one or two are already majoring in other sciences. Veterans of former classes come as assistants on the one week trip. Thus, the students considering majoring in Geosciences are mentored by the older students. And the veterans add to their petrology and mineralogy education through instruction of the younger students. The trip is expensive. Costs are covered by income from endowed funds set up to provide field experiences for undergraduates. This course helps tremendously in introducing eastern students to the geology that is so dramatically displayed in the west, and that is pretty well covered over by houses and trees and highways in the east.

Hollister, L. S.

2003-12-01

33

Journal of Mineralogical and Petrological Sciences  

NASA Astrophysics Data System (ADS)

Official journal of Japan Association of Mineralogical Sciences (JAMS), focusing on mineralogical and petrological sciences and their related fields. Journal of Mineralogical and Petrological Sciences (JMPS) is the successor journal to both “Journal of Mineralogy, Petrology and Economic Geology” and “Mineralogical Journal”. Journal of Mineralogical and Petrological Sciences (JMPS) is indexed in the ISI database (Thomson Reuters), the Science Citation Index-Expanded, Current Contents/Physical, Chemical & Earth Sciences, and ISI Alerting Services.

34

Petrology of the unbrecciated eucrites  

NASA Astrophysics Data System (ADS)

Twenty-nine unbrecciated eucrites have been thoroughly characterized in terms of the petrologic factors that affect their spectra, such as mineral chemistry, modal adundances, grain sizes, and textures. We have conducted a combined petrologic and spectral study designed to provide insight into the petrogenesis of the basaltic crust of Vesta and the variety of rock-types that exist within it, as well as aid in the petrologic interpretation of spectra to be collected by the Dawn orbiting spacecraft. This paper details the petrology part of the study. Unbrecciated eucrite samples were selected to avoid the complications of lithologic mixing in the accompanying spectral study. A wide variety of textural types are seen within the basaltic eucrites, encompassing quenched, coarse-grained, and granoblastic samples. Zoned pyroxenes in eucrites and those that preserve a history of initial rapid cooling are rare. Nearly all eucrite samples have been thermally metamorphosed and would commonly be classified as equilibrated; however, this term reflects only the quadrilateral (Mg, Fe, and Ca) compositions of pyroxenes, and considerable variations are seen within the minor elements (Al, Ti, and Cr) in pyroxenes as well as plagioclase compositions. Determination of both pyroxene and plagioclase compositions together with pyroxene geothermometry provides a better estimate for the relative degree of thermal metamorphism a eucrite has experienced. The petrologic differences observed here might allow different eucrites to be distinguished spectrally. This is especially true for the varying pyroxene compositions as the spectra of eucrites are dominated by absorption features attributed to pyroxene.

Mayne, R. G.; McSween, H. Y., Jr.; McCoy, T. J.; Gale, A.

2009-02-01

35

Petrology and Geochemistry of LEW 88663 and PAT 91501: High Petrologic L Chondrites  

Microsoft Academic Search

Primitive achondrites (e.g., Acapulco, Lodran) are believed to be highly metamorphosed chondritic materials, perhaps up to the point of anatexis in some types. Low petrologic grade equivalents of these achondrites are unknown, so the petrologic transition from chondritic to achondritic material cannot be documented. However, there are rare L chondrites of petrologic grade 7 that may have experienced igneous processes,

D. W. Mittlefehldt; M. M. Lindstrom; S. W. Field

1993-01-01

36

Virtual Quarry  

NSDL National Science Digital Library

This interactive virtual tour for younger students lets them 'drive' a quarry truck and visit a rock quarry to see how the rock is mined, processed and transported, and what the aggregate is used for. The tour includes safety tips for visiting quarries. They can also 'restore' an abandoned quarry by planting virtual grass, reeds, and trees, view movies about quarries, and use a virtual microscope to look at some rock samples. There are also links to lesson plans on the use and restoration of quarries.

37

Mind Over Magma: The Story of Igneous Petrology  

NASA Astrophysics Data System (ADS)

In the centuries that enquiring minds have studied and theorized about igneous rocks, much progress has been made, both in accumulating observations and in developing theories. Yet, writing a history of this progress is a daunting undertaking. The volume of the literature is vast and in multiple languages; the various lines of inquiry are diverse and complex; and the nomenclature is sometimes abstruse. On top of these challenges, many of its principal issues have yet to find a definitive consensus. With the exception of a few topical studies, historians of science have virtually avoided the subject. In Mind Over Magma: The Story of Igneous Petrology, Davis Young has taken on the challenge of writing a comprehensive survey of the study of igneous rocks, and the result has been a remarkable book of meticulous scholarship. Igneous petrology is a vast subject, and it is not obvious how best to organize its history. Young takes a topical approach, generally grouping together various studies by either the problem being investigated or the method of attack. These topics span the earliest times to the present, with an emphasis on recurring themes, such as the causes of magmatic diversity and the origins of the granitic rocks. The range of topics includes most of the subjects central to the field over its history. As much as is practical, topics are discussed in chronological order, and along the way, the reader is treated to biographical sketches of many of the key contributors. This organization proves effective in dealing with the multitude of concepts.

Snyder, Don

2004-01-01

38

Sedimentary petrology. 2nd edition  

SciTech Connect

The second edition of Sedimentary Petrology is extensively revised and updated; much effort has been expended to strengthen the weaknesses of the earlier edition, and much of this effort has been successful. It consists of sixteen chapters. Following two introductory chapters (occurrence of sedimentary rocks; weathering and soils), eleven chapters cover the various sedimentary rock types. Coverage is allocated in proportion to their relative abundance and relative ease of study -- three chapters on conglomerates and sandstones (textures and structures, composition, and diagenesis); one on mud rocks; three on carbonates (limestone textures, structures, and environments; limestone mineralogy and diagenesis; and dolostones); and one each on evaporites, cherts, iron-rich rocks, and phosphorites. A novel and useful chapter on paleogeothermometry rounds out the discussion of rocks, followed by chapters on The Development of a Research Project'' and common laboratory methods.

Blatt, H.

1992-01-01

39

Organic petrological studies on immature source rocks  

Microsoft Academic Search

Organic petrology is a marginal science that is quite practicable. At present, it has developed into a routine research tool\\u000a that is widely applied in petroleum exploration and assessment. Based on several years’ research of the authors, this paper\\u000a presents the advances in organic petrological studies on immature source rocks, including the classification and characteristics\\u000a of macerais, the composition of

Li Xianqing; Xiong Bo; Zhong Ningning; Ma Anlai; Wang Tieguan; Zhang Aiyun

2004-01-01

40

Experimental Petrology and Geochemistry of Volatile-Bearing Silicate Melts.  

National Technical Information Service (NTIS)

The focus of this project is the application of experimental petrology and geochemistry to problems in petrology and geochemistry, with particular emphasis on understanding the behavior and properties of the principal volatile components, H2O and CO2, and...

E. Stolper

2013-01-01

41

Petrology of the Apollo 12 Pigeonite Basalt Suite.  

National Technical Information Service (NTIS)

A comparative petrologic study of the Apollo 12 pigeonite basalt suite has been undertaken to answer the following questions: (1) What are the textural and petrologic variations within the pigeonite suite. (2) Are these variations consistent with the hypo...

W. S. Baldridge D. W. Beaty S. M. R. Hill A. L. Albee

1979-01-01

42

Microscope Simulation  

NSDL National Science Digital Library

Here you can read and find out about different kinds of microscopes - what you can see in them and how to prepare specimens for a particular microscope. You can also try the four different microscope simulators and watch and compare images taken with phase contrast microscopes, fluorescence microscopes, transmission electron microscopes and scanning tunneling microscopes. Test your knowledge of microscopes by answering the 20 questions in the "Microscope quiz".

2012-09-14

43

Insights into eruption precursors: linking the petrological and geophysical record  

NASA Astrophysics Data System (ADS)

Active volcanoes are monitored through a variety of geophysical techniques including GPS, satellite based radar (InSAR), gas emissions, ground deformation and seismicity to detect signs of unrest. A time series of these geophysical processes, can thus be constrained that may for example provide a record of the magma ascent, the deflation or inflation of a magma body. Conversely, crystals hosted in the magma body provide a direct record of the magmatic processes experienced during its growth as the magma evolved. Perturbations within the magmatic system often result in renewed crystal growth of a different composition that result in highly zoned crystals. Each discrete zoned can be geochemically fingerprinted by in-situ microanalytical techniques such as electron probe microanalyser (EPMA) and scanning electron microscope (SEM) to identify the magmatic process(es) responsible for the generation of these crystals. Combining this knowledge from multiple crystals within a single eruption or unit allows the evolution of the magmatic system to be unravelled and pieced together. Importantly, the timescales of these processes can be assessed through the chemical relaxation of chemical gradients across the compositional zones through diffusion techniques. This permits an independently constrained petrology time series to be constrained that can be combined with the geophysical time series providing insights into magmatic processes that occur prior to eruption. However, this approach to link both a petrological and geophysical time series of an active volcano requires a relatively rare and unique set of circumstances. Not only must the volcano be active, it must have a good geophysical record extending at least 10-20 years, have a well characterised recent eruption with zoned crystals for which the relevant diffusion coefficients are known to allow access to the samples. One such eruption is the 2010 Eyjafjallajökull. The summit eruption was preceded by an effusive flank eruption at Fimmvörduháls from the 20th March-12th April. Here we present a petrological time series constrained from diffusion modelling of olivine crystals and compare it to the geodetic and seismicity recorded

Saunders, K.; Biggs, J.; Blundy, J.

2012-04-01

44

Magmas and magmatic rocks: An introduction to igneous petrology  

SciTech Connect

This book melds traditional igneous petrology with the emerging science of planetary petrology to provide an account of current ideas on active magmatic and volcanic processes, drawing examples from all igneous provinces of the world as well as from the moon and planets. It reviews the history and development of concepts fundamental to modern igneous petrology and includes indepth sections on magmas, magnetic differentiation and volcanology.

Middlemost, E.A.K.

1986-01-01

45

Rethinking how Undergraduate ``Hard Rock'' Petrology is Taught  

NASA Astrophysics Data System (ADS)

A course in "hard rock" petrology forms a core component of undergraduate training in the geosciences. In most cases, the subjects of igneous and metamorphic petrology are combined in a single course and the course is traditionally structured so that the two subjects are covered in series. This approach enables students to focus on each subject separately, with knowledge of igneous rocks helping students to understand metamorphic rock protoliths. Student assessment shows, however, that this approach tends to compartmentalize learning and the two main subjects might just as well be taught in separate courses. In practical applications such as fieldwork, students must be able to access their understanding of igneous and metamorphic rocks virtually simultaneously. To better integrate student learning, I developed a spiral learning approach to teaching petrology (e.g., Bruner, 1990; Dyar et al., 2004) so that commonalities could be revisited several times over the course of a semester and, in so doing, students' grasp of the fundamental insights provided by igneous and metamorphic rocks could be scaffolded into greater understanding. The course initially focuses on the dynamics of the environments in which igneous and metamorphic rocks form: heat flow, fluid flow, and plate tectonics. Several subsequent weeks explore topics relevant to identifying and understanding igneous and metamorphic rocks in the field: crystal nucleation and growth, the roles of pressure and heat, and field classification. Laboratory exercises parallel this structure, also emphasizing observations that are valuable in the field: the relationship between minerals and rocks, textural observations, and general rock classification. The final portion of the course explores “hard rocks” in more detail with a greater emphasis on the interplay between chemistry and mineralogy. A variety of learner-centered activities in the course help students bridge the gap between novice and expert and include more explicit emphasis on visualization and on helping students become comfortable with interpreting data numerically and graphically. Pen tablet computers are used extensively in the laboratory for visualization, photomicrograph capture, and annotation. Cooperative learning activities developed for this course make use of learning methods such as pair share, round-robin, small group explorations case studies, and jigsaw exercises (sometimes as introduction to, sometimes as review of material), and Jeopardy-style review sessions. On an assessment questionnaire at the end of the semester students ranked the in-class cooperative learning activities as on par with lectures and homework exercises in facilitating their learning. Students reported satisfactory attainment of three major goals identified for the course even though they were not explicitly reminded of these goals at the time of assessment. References cited: Bruner, J., 1990. Acts of Meaning. Harvard University Press.; Dyar, M.D., Gunter, M.E., Davis, J.C., and Odell, M.R., 2004. Integration of new methods into teaching mineralogy; Huba, M.E. and Freed, J.E., 2000. Learner-centered Assessment on College Campus: Shifting the Focus from Teaching to Learning. Allyn and Bacon.

Reid, M. R.

2010-12-01

46

Athena Microscopic Imager investigation  

NASA Astrophysics Data System (ADS)

The Athena science payload on the Mars Exploration Rovers (MER) includes the Microscopic Imager (MI). The MI is a fixed-focus camera mounted on the end of an extendable instrument arm, the Instrument Deployment Device (IDD). The MI was designed to acquire images at a spatial resolution of 30 microns/pixel over a broad spectral range (400-700 nm). The MI uses the same electronics design as the other MER cameras but has optics that yield a field of view of 31 × 31 mm across a 1024 × 1024 pixel CCD image. The MI acquires images using only solar or skylight illumination of the target surface. A contact sensor is used to place the MI slightly closer to the target surface than its best focus distance (about 66 mm), allowing concave surfaces to be imaged in good focus. Coarse focusing (~2 mm precision) is achieved by moving the IDD away from a rock target after the contact sensor has been activated. The MI optics are protected from the Martian environment by a retractable dust cover. The dust cover includes a Kapton window that is tinted orange to restrict the spectral bandpass to 500-700 nm, allowing color information to be obtained by taking images with the dust cover open and closed. MI data will be used to place other MER instrument data in context and to aid in petrologic and geologic interpretations of rocks and soils on Mars.

Herkenhoff, K. E.; Squyres, S. W.; Bell, J. F.; Maki, J. N.; Arneson, H. M.; Bertelsen, P.; Brown, D. I.; Collins, S. A.; Dingizian, A.; Elliott, S. T.; Goetz, W.; Hagerott, E. C.; Hayes, A. G.; Johnson, M. J.; Kirk, R. L.; McLennan, S.; Morris, R. V.; Scherr, L. M.; Schwochert, M. A.; Shiraishi, L. R.; Smith, G. H.; Soderblom, L. A.; Sohl-Dickstein, J. N.; Wadsworth, M. V.

2003-11-01

47

Using Dynamic Digital Maps to Teach Petrology  

NSDL National Science Digital Library

In this session we will examine how to utilize Dynamic Digital Maps (DDMs) in undergraduate petrology courses to bring inaccessible and exciting volcanic field areas to the students in the classroom and to engage the students in authentic research experiences. A DDM is a stand-alone "presentation manager" computer program that contains interactive maps, analytical data, digital images and movies. They are essentially complete geologic maps in digital format, available on CD-ROM and on line. We have developed two different kinds of exercises that use DDMs to provide field-based context for undergraduate research projects in petrology. In one, the students use the DDM of the Tatara-San Pedro volcanic complex of the Andes Mountains of central Chile to develop a group research poster on part of the volcano's evolution, to present to the class, modeled after what would be presented at a national meeting. The second exercise focuses on the Springville Volcanic field, where the students try to understand the magma evolution using both field relations and quantitative modeling skills. Read a complete description of how dynamic digital maps work, with more ideas for the classroom. (from Teaching with Data, Simulations and Models)

Condit, Christopher D.

48

Microscope basics.  

PubMed

This chapter provides information on how microscopes work and discusses some of the microscope issues to be considered in using a video camera on the microscope. There are two types of microscopes in use today for research in cell biology-the older finite tube-length (typically 160mm mechanical tube length) microscopes and the infinity optics microscopes that are now produced. The objective lens forms a magnified, real image of the specimen at a specific distance from the objective known as the intermediate image plane. All objectives are designed to be used with the specimen at a defined distance from the front lens element of the objective (the working distance) so that the image formed is located at a specific location in the microscope. Infinity optics microscopes differ from the finite tube-length microscopes in that the objectives are designed to project the image of the specimen to infinity and do not, on their own, form a real image of the specimen. Three types of objectives are in common use today-plan achromats, plan apochromats, and plan fluorite lenses. The concept of mounting video cameras on the microscope is also presented in the chapter. PMID:23931500

Sluder, Greenfield; Nordberg, Joshua J

2013-01-01

49

Modeling petrological geodynamics in the Earth's mantle  

NASA Astrophysics Data System (ADS)

We have developed an approach that combines principles of fluid dynamics and chemical thermodynamics into a fully coupled scheme to model geodynamic and petrological evolution of the Earth's mantle. Transport equations involving pressure, temperature, velocities, and bulk chemical composition are solved for one or more dynamic phases and interfaced with the thermodynamic solutions for equilibrium mineralogical assemblages and compositions. The mineralogical assemblage and composition are computed on a space-time grid, assuming that local thermodynamic equilibrium is effectively achieved. This approach allows us to simultaneously compute geophysical, geochemical, and petrological properties that can be compared with a large mass of observational data to gain insights into a variety of solid Earth problems and melting phenomena. We describe the salient features of our numerical scheme and the underlying mathematical principles and discuss a few selected applications to petrological and geophysical problems. First, it is shown that during the initial stage of passive spreading of plates, the composition of the melt near Earth's surface is in reasonable agreement with the average major element composition of worldwide flood basalts. Only the silica content from our model is slightly higher that in observational data. The amount of melt produced is somewhat lower than the estimated volumes for extrusive and upper crustal intrusive igneous rocks from large igneous provinces suggesting that an active upwelling of a larger mantle region should be considered in the process. Second, we have modeled a plume upwelling under a moving plate incorporating the effects of mineralogy on the density structure and viscous dissipation on the heat transport equation. The results show how these effects promote mantle instability at the base of the lithosphere. Third, we have considered a mantle convection model with viscosity and density directly related to the local equilibrium mineralogical assemblage. Interesting lateral variations and significant differences in the viscosity structure of the upper and lower mantle are revealed from our model results. The averaged viscosity variations with depth retrieved from our numerical simulations seem to reproduce the main features of the mantle viscosity structure under the Pacific ocean obtained from recent studies based on inversion of seismic data.

Tirone, M.; Ganguly, J.; Morgan, J. P.

2009-04-01

50

Virtual Courseware: Drosophila  

NSDL National Science Digital Library

In this virtual lab exercise, students can discover and apply principles of genetic inheritance by studying fruit flies (Drosophila) in an interactive online environment. The exercise allows them to order fruit fly mutants from a web merchant, mate the flies in an incubator, anesthetize flies for observation, examine them under a microscope, and analyze the data from offspring to determine patterns of inheritance. Notes and experimental data can be saved online in a virtual notebook and used to generate a report. The exercise concludes with an online quiz, and alignments to state and national standards are included.

51

Absence of Correlations Between Opaque Petrology and Natural Remanence Polarity in Canary Island Lavas.  

National Technical Information Service (NTIS)

The titanomagnetite oxidation state, separate ilmenite abundance and other petrological properties have been measured in specimens from 168 Miocene to Pliocene Canary Island lava flows. No correlation is found between opaque petrological parameters and na...

J. M. Ade-Hall N. D. Watkins

1969-01-01

52

PETROLOGY AND RADIOGEOLOGY OF THE STRIPA PLUTON  

SciTech Connect

To better define the character of the rock encompassing the thermomechanical and hydrological experiments at the Stripa mine in central Sweden, and to help determine the size of the Stripa pluton, detailed studies were conducted of the petrology and radiogeology of the quartz monzonite and adjacent rocks. Petrologic studies emphasized optical petrography, with supplementary X-ray diffraction, X-ray fluorescence and microprobe analyses. Radiogeologic investigations were based primarily on surface and underground gamma-ray spectrometric measurements of uranium, thorium and potassium, supplemented by laboratory gamma spectrometric analyses and fission-track radiographic determinations of the locations and abundance of uranium in the rock matrix. Both the quartz monzonite and the metavolcanic leptite which it intruded are strongly fractured. Two stages of fracture filling are evident; an earlier stage encompassing quartz, sericite, feldspar, epidote, and chlorite, and a later stage dominated by carbonate minerals. The Stripa quartz monzonite is chemically and mineralogically distinct from other plutons in the region. Muscovite is the predominant mica in the quartz monzonite; biotite has been altered to chlorite, hornblende is absent, and accessory minerals are scarce. In contrast, in other plutons in the Stripa region biotite and hornblende are prominent mafic minerals and accessory minerals are abundant. The Stripa quartz monzonite is also considerably more radioactive than the leptite and other plutons in the region. Uranium and thorium abundances are both- 30 ppm, considerably higher than in "normal" granitic rocks where the thorium-to-uranium ratio generally exceeds 2. Potassium-argon dating of muscovite from the Stripa quartz monzonite indicates that this rock may be older, at 1691 million years than granitic rock of the neighboring Gusselby and Kloten massifs, whose ages, based on K-Ar dating of biotite, are respectively 1604 and 1640 m.y. Heat flow and heat productivity considerations show that although Stripa quartz monzonite contains high abundances of radioelements, the pluton has little effect on the regional heat flow. If it occurs in a layered plutonic setting, it is not more than 1.5 km thick; otherwise it may comprise a stock, dike, or border phase that is relatively small compared with the large granitic plutons exposed in the region.

Wollenberg, Harold; Flexser, Steve; Andersson, Lennart

1980-12-01

53

Virtual Colonoscopy  

MedlinePLUS

... does not allow the doctor to remove tissue samples or polyps. Virtual colonoscopy does not detect pre-cancerous polyps smaller than 10 millimeters. Medicare and many health insurance plans do not pay for virtual colonoscopy cancer screening. ...

54

Virtual reality  

Microsoft Academic Search

Although the terms cyberspace and virtual reality have been around for years, virtual reality as an industry is in its infancy. The term virtual reality is credited to Jaron Lanier, founder of VPL Research; earlier experimenters, like Myron Krueger in the mid-1970s, used phrases like artificial reality. William Gibson coined cyberspace in his 1984 science fiction novel. Neuromancer. Few technologies

C. Machover; S. E. Tice

1994-01-01

55

The petrological expression of early Mars volcanism  

NASA Astrophysics Data System (ADS)

Crystallization products of liquids produced by partial melting of a possible Martian mantle for conditions covering the earliest Noachian era to the most recent Amazonian times have been modeled using the MELTS thermodynamic calculator. The results imply a transition from low-calcium pyroxene dominated assemblages in the Noachian to high-calcium pyroxene assemblages in the Hesperian and Amazonian, which is remarkably consistent with observations made by orbiting visible and near-infrared spectrometers. This transition is interpreted as the consequence of the thermal evolution of the mantle, with no need for exotic conditions, such as higher water content or nonchondritic Ca/Al ratio of the mantle source, to produce low-calcium pyroxene rich lithologies. Our results are compatible with numerical models of the thermal evolution of Mars that predict high production rates of crust on early Mars, implying that Noachian rocks exposed at the surface may be petrological expressions of this volcanism rather than being associated with mantle overturn following the crystallization of a magma ocean.

Baratoux, D.; Toplis, M. J.; Monnereau, M.; Sautter, V.

2013-01-01

56

SNC meteorites - Clues to Martian petrologic evolution?  

NASA Astrophysics Data System (ADS)

Shergottites, nakhlites and the Chassigny meteorites (SNC group) may have originated on Mars. The shergottites are medium-grained basalts, the nakhlites are pyroxenites and the Chassigny is a dunite. The SNC group is petrologically diverse but differs from all other known achondrites in terms of mineral chemistry, the redox state, the oxygen isotopic composition and the radiometric ages. The SNC stones are mafic and ultramafic cumulate rocks with mineralogies that indicate rapid cooling and crystallization from tholeiitic magmas which contained water and experienced a high degree of oxidation. The characteristics suggest formation from a large parent body, i.e., a planet, but not earth. The estimated ages for the rocks match the estimated ages for several mapped Martian volcanoes in the Tharsis region. Additionally, the elemental and isotopic abundances of atmospheric gases embedded in melts in the SNC stones match Viking Lander data for the Martian atmosphere. However, reasons are cited for discounting the possibility that a large meteorite(s) collided with Mars about 180 myr ago and served as the mechanism for ejecting the SNC stones to earth.

McSween, H. Y.

1985-11-01

57

Thermal structure of the lithosphere: a petrologic model.  

PubMed

A preliminary evaluation of the thermal history of the upper mantle as determined by petrologic techniques indicates a general correspondence with theoretically derived models. The petrologic data supply direct information which may be used as an independent calibration of calculated models, serve as a base for evaluating the assumptions of the theoretical approach, and allow more careful selection of the variables describing mantle thermal properties and processes. Like the theoretical counterpart, the petrological approach indicates that the lithosphere is dominated by two thermal regimes: first, there is a continental regime which cools at rates of the order of 10(9) years and represents the longterm cooling of the earth. Secondly, superimposed on the continental evolution is the thermal event associated with the formation of an oceanic basin, and which may be thought of as a 10(8) year convective perturbation on the continental cycle. Of special interest is petrologic evidence for a sudden steepening of the thermal gradients across the lithosphere-asthenosphere boundary not seen in the theoretical models. The unexpected change of slope points to the need for a critical reevaluation of the thermal processes and properties extant in the asthenosphere. The potential of the petrologic contribution has yet to be fully realized. For a start, this article points to an important body of independent evidence critical to our understanding of the earth's thermal history. PMID:17738235

Macgregor, I D; Basu, A R

1974-09-20

58

Virtual Worlds for Virtual Organizing  

Microsoft Academic Search

\\u000a The members and resources of a virtual organization are dispersed across time and space, yet they function as a coherent entity\\u000a through the use of technologies, networks, and alliances. As virtual organizations proliferate and become increasingly important\\u000a in society, many may exploit the technical architecture s of virtual worlds, which are the confluence of computer-mediated\\u000a communication, telepresence, and virtual reality

Diana Rhoten; Wayne Lutters

2010-01-01

59

Virtual spaces and virtual manufacturing  

Microsoft Academic Search

This article presents new problems linked to the increasing use of virtual spaces in the building of new types of manufacturing, currently known as virtual manufacturing (VM). VM has many consequences in the activity of industrial companies whatever the size, economic sector or geographical area. Particular attentions are paid to virtual spaces, manufacturing and collaboration, skills matrix and manufacturability, CAD

N. Kraiem

2001-01-01

60

Microscopic colitis  

PubMed Central

Microscopic colitis may be defined as a clinical syndrome, of unknown etiology, consisting of chronic watery diarrhea, with no alterations in the large bowel at the endoscopic and radiologic evaluation. Therefore, a definitive diagnosis is only possible by histological analysis. The epidemiological impact of this disease has become increasingly clear in the last years, with most data coming from Western countries. Microscopic colitis includes two histological subtypes [collagenous colitis (CC) and lymphocytic colitis (LC)] with no differences in clinical presentation and management. Collagenous colitis is characterized by a thickening of the subepithelial collagen layer that is absent in LC. The main feature of LC is an increase of the density of intra-epithelial lymphocytes in the surface epithelium. A number of pathogenetic theories have been proposed over the years, involving the role of luminal agents, autoimmunity, eosinophils, genetics (human leukocyte antigen), biliary acids, infections, alterations of pericryptal fibroblasts, and drug intake; drugs like ticlopidine, carbamazepine or ranitidine are especially associated with the development of LC, while CC is more frequently linked to cimetidine, non-steroidal antiinflammatory drugs and lansoprazole. Microscopic colitis typically presents as chronic or intermittent watery diarrhea, that may be accompanied by symptoms such as abdominal pain, weight loss and incontinence. Recent evidence has added new pharmacological options for the treatment of microscopic colitis: the role of steroidal therapy, especially oral budesonide, has gained relevance, as well as immunosuppressive agents such as azathioprine and 6-mercaptopurine. The use of anti-tumor necrosis factor-? agents, infliximab and adalimumab, constitutes a new, interesting tool for the treatment of microscopic colitis, but larger, adequately designed studies are needed to confirm existing data.

Ianiro, Gianluca; Cammarota, Giovanni; Valerio, Luca; Annicchiarico, Brigida Eleonora; Milani, Alessandro; Siciliano, Massimo; Gasbarrini, Antonio

2012-01-01

61

The Petrology of Very Small Rocks  

NASA Astrophysics Data System (ADS)

A hallmark of Eric Essene`s research and teaching is to `look at your sample` before advanced analysis. We apply this common sense yet sometimes ignored advice to explore the relation between mineral inclusions within zircon and host rock type from 4 suites: two with known genesis and two that are uncertain. A wide range of techniques can be applied to "look" at zircons and their inclusions as the prelude to in situ isotopic, structural, and chemical analysis including: optics, acid etching, SEM (SE, CL, EDS, BSE, EBSD), cold cathode CL, SIMS, and X-ray mapping. Zircons from the Sierra Nevada batholith have granitic parentage, and contain polymineralic assemblages of quartz ± biotite ± K-feldspar ± plagioclase ± muscovite ± apatite ± Fe oxide ± sphene ± amphibole. Zircons from young ocean crust have gabbroic parentage, and contain plagioclase ± intergrown Fe-Ti oxides ± apatite ± amphibole ± clinopyroxene, and rarely contain quartz. The mantle suite of zircons from kimberlite is united by chemical and physical similarities, but occurs as xenocrysts of uncertain origin. They may contain euhedral tetragonal ZrO2 ± olivine ± clinopyroxene ± apatite, in cavities up to 100 microns long. Thus the kimberlite xenocrysts are consistent with mafic or ultramafic composition. Detrital zircons from the Jack Hills metaconglomerate range in age from 4.4 to 3.1 Ga and are also of uncertain genesis. Inclusions include common quartz ± apatite ± muscovite ± monazite ± rutile ± xenotime ± Fe-oxide ± Fe sulfide. The Jack Hills zircon inclusions, irrespective of age, indicate silica saturated magmas, are most similar to those in granitic rocks, and are distinctly different from zircons in mafic ocean crust, but this does not preclude formation in small volumes of evolved magma. The observation that zircon inclusions are in apparent equilibrium demonstrates that these inclusion assemblages carry petrologic information and can be studied as `small rocks`.

Valley, J. W.; Cavosie, A. J.

2006-12-01

62

Electronic Blending in Virtual Microscopy  

ERIC Educational Resources Information Center

Virtual microscopy (VM) is a relatively new technology that transforms the computer into a microscope. In essence, VM allows for the scanning and transfer of glass slides from light microscopy technology to the digital environment of the computer. This transition is also a function of the change from print knowledge to electronic knowledge, or as…

Maybury, Terrence S.; Farah, Camile S.

2010-01-01

63

Highly Sophisticated Virtual Laboratory Instruments in Education  

NASA Astrophysics Data System (ADS)

Many areas of Science have advanced or stalled according to the ability to see what can not normally be seen. Visual understanding has been key to many of the world's greatest breakthroughs, such as discovery of DNAs double helix. Scientists use sophisticated instruments to see what the human eye can not. Light microscopes, scanning electron microscopes (SEM), spectrometers and atomic force microscopes are employed to examine and learn the details of the extremely minute. It's rare that students prior to university have access to such instruments, or are granted full ability to probe and magnify as desired. Virtual Lab, by providing highly authentic software instruments and comprehensive imagery of real specimens, provides them this opportunity. Virtual Lab's instruments let explorers operate virtual devices on a personal computer to examine real specimens. Exhaustive sets of images systematically and robotically photographed at thousands of positions and multiple magnifications and focal points allow students to zoom in and focus on the most minute detail of each specimen. Controls on each Virtual Lab device interactively and smoothly move the viewer through these images to display the specimen as the instrument saw it. Users control position, magnification, focal length, filters and other parameters. Energy dispersion spectrometry is combined with SEM imagery to enable exploration of chemical composition at minute scale and arbitrary location. Annotation capabilities allow scientists, teachers and students to indicate important features or areas. Virtual Lab is a joint project of NASA and the Beckman Institute at the University of Illinois at Urbana- Champaign. Four instruments currently compose the Virtual Lab suite: A scanning electron microscope and companion energy dispersion spectrometer, a high-power light microscope, and a scanning probe microscope that captures surface properties to the level of atoms. Descriptions of instrument operating principles and uses are also part of Virtual Lab. The Virtual Lab software and its increasingly rich collection of specimens are free to anyone. This presentation describes Virtual Lab and its uses in formal and informal education.

Gaskins, T.

2006-12-01

64

Virtual Neuron  

NSDL National Science Digital Library

Neurons are able to communicate with each other using biochemicals called neurotransmitters. Use Virtual Neuron to explore neurotransmitter properties, make neurons fire, and manipulate neural circuits.

2009-04-14

65

Virtual Congresses  

PubMed Central

A new form of scientific medical meeting has emerged in the last few years—the virtual congress. This article describes the general role of computer technologies and the Internet in the development of this new means of scientific communication, by reviewing the history of “cyber sessions” in medical education and the rationale, methods, and initial results of the First Virtual Congress of Cardiology. Instructions on how to participate in this virtual congress, either actively or as an observer, are included. Current advantages and disadvantages of virtual congresses, their impact on the scientific community at large, and future developments and possibilities in this area are discussed.

Lecueder, Silvia; Manyari, Dante E.

2000-01-01

66

Virtual congresses.  

PubMed

A new form of scientific medical meeting has emerged in the last few years--the virtual congress. This article describes the general role of computer technologies and the Internet in the development of this new means of scientific communication, by reviewing the history of "cyber sessions" in medical education and the rationale, methods, and initial results of the First Virtual Congress of Cardiology. Instructions on how to participate in this virtual congress, either actively or as an observer, are included. Current advantages and disadvantages of virtual congresses, their impact on the scientific community at large, and future developments and possibilities in this area are discussed. PMID:10641960

Lecueder, S; Manyari, D E

67

Virtual Laboratories and Virtual Worlds  

NASA Astrophysics Data System (ADS)

Since we cannot put stars in a laboratory, astrophysicists had to wait till the invention of computers before becoming laboratory scientists. For half a century now, we have been conducting experiments in our virtual laboratories. However, we ourselves have remained behind the keyboard, with the screen of the monitor separating us from the world we are simulating. Recently, 3D on-line technology, developed first for games but now deployed in virtual worlds like Second Life, is beginning to make it possible for astrophysicists to enter their virtual labs themselves, in virtual form as avatars. This has several advantages, from new possibilities to explore the results of the simulations to a shared presence in a virtual lab with remote collaborators on different continents. I will report my experiences with the use of Qwaq Forums, a virtual world developed by a new company (see http://www.qwaq.com).

Hut, Piet

2008-05-01

68

Formation of cryolite and other aluminofluorides: A petrologic review  

Microsoft Academic Search

Petrologic reviews are provided for 17 confirmed localities of cryolite, and for occurrences of 19 other aluminofluorides. Four environments can be recognised: granitic, carbonatitic, volcanic and aqueous. Cryolite, partly replaced by other aluminofluorides, forms at the post-magmatic stage of granite evolu­ tion in alkali granite pegmatites, albitised riebeckite granites and hydrothermal bodies. The associated magmatic granites are post- or non-orogenic,

J. C. BAILEY

1980-01-01

69

Petrology, Mineralogy, and Genesis of Lunar Crystalline Igneous Rocks  

Microsoft Academic Search

Information on the mineralogy and petrology of the Apollo 11 crystalline basaltic rocks, obtained by about 35 groups of investigators, is summarized and used as a basis for speculation. The textural assemblage indicates near-surface, rapid crystallization from low-viscosity basaltic magmas under low oxygen pressures. The basalts are subsilicic and subalkaline, but only locally, titaniferous. Terrestrial alkali basalts could, through alkali

G. Malcolm Brown

1970-01-01

70

Petrologic constraints on the origin of the Moon  

Microsoft Academic Search

The authors place special emphasis on recent data from the Apollo 14 site. It is the uniqueness of this sample suite, corroborated by orbital geochemical data, that establishes the existence of lateral heterogeneities in the lunar crust and mantle. The authors present brief reviews of previous data on highland and mare petrology, followed by more detailed summaries of the Apollo

John W. Shervais; Lawrence A. Taylor

1986-01-01

71

Microscope and method of use  

DOEpatents

A method and apparatus for electronically focusing and electronically scanning microscopic specimens are given. In the invention, visual images of even moving, living, opaque specimens can be acoustically obtained and viewed with virtually no time needed for processing (i.e., real time processing is used). And planar samples are not required. The specimens (if planar) need not be moved during scanning, although it will be desirable and possible to move or rotate nonplanar specimens (e.g., laser fusion targets) against the lens of the apparatus. No coupling fluid is needed, so specimens need not be wetted. A phase acoustic microscope is also made from the basic microscope components together with electronic mixers. 7 figs.

Bongianni, W.L.

1984-04-17

72

Microscope and method of use  

DOEpatents

A method and apparatus for electronically focusing and electronically scanning microscopic specimens are given. In the invention, visual images of even moving, living, opaque specimens can be acoustically obtained and viewed with virtually no time needed for processing (i.e., real time processing is used). And planar samples are not required. The specimens (if planar) need not be moved during scanning, although it will be desirable and possible to move or rotate nonplanar specimens (e.g., laser fusion targets) against the lens of the apparatus. No coupling fluid is needed, so specimens need not be wetted. A phase acoustic microscope is also made from the basic microscope components together with electronic mixers.

Bongianni, W.L.

1981-08-18

73

Microscope and method of use  

DOEpatents

A method and apparatus for electronically focusing and electronically scanning microscopic specimens are given. In the invention, visual images of even moving, living, opaque specimens can be acoustically obtained and viewed with virtually no time needed for processing (i.e., real time processing is used). And planar samples are not required. The specimens (if planar) need not be moved during scanning, although it will be desirable and possible to move or rotate nonplanar specimens (e.g., laser fusion targets) against the lens of the apparatus. No coupling fluid is needed, so specimens need not be wetted. A phase acoustic microscope is also made from the basic microscope components together with electronic mixers.

Bongianni, Wayne L. (Los Alamos, NM)

1984-01-01

74

Virtual Labs and Virtual Worlds  

NASA Astrophysics Data System (ADS)

Virtual Labs and Virtual Worlds Coastline Community College has under development several virtual lab simulations and activities that range from biology, to language labs, to virtual discussion environments. Imagine a virtual world that students enter online, by logging onto their computer from home or anywhere they have web access. Upon entering this world they select a personalized identity represented by a digitized character (avatar) that can freely move about, interact with the environment, and communicate with other characters. In these virtual worlds, buildings, gathering places, conference rooms, labs, science rooms, and a variety of other “real world” elements are evident. When characters move about and encounter other people (players) they may freely communicate. They can examine things, manipulate objects, read signs, watch video clips, hear sounds, and jump to other locations. Goals of critical thinking, social interaction, peer collaboration, group support, and enhanced learning can be achieved in surprising new ways with this innovative approach to peer-to-peer communication in a virtual discussion world. In this presentation, short demos will be given of several online learning environments including a virtual biology lab, a marine science module, a Spanish lab, and a virtual discussion world. Coastline College has been a leader in the development of distance learning and media-based education for nearly 30 years and currently offers courses through PDA, Internet, DVD, CD-ROM, TV, and Videoconferencing technologies. Its distance learning program serves over 20,000 students every year. sponsor Jerry Meisner

Boehler, Ted

2006-12-01

75

Virtual Memory  

Microsoft Academic Search

\\\\The need for automatic storage allocation arises from desires for program modularity, machine independence, and resource sharing. Virtual memory is an elegant way of achieving these objectives. In a virtual memory, the addresses a program may use to identify information are distinguished from the addresses the memory system uses to identify physical storage sites, and program-generated addresses are translated automatically

Peter J. Denning

1970-01-01

76

Virtual termite  

NSDL National Science Digital Library

3D virtual image of a termite (Order Isoptera). This movie is also available as a Virtual Reality Modeling Language (VRML) model. The VRML models are more interactive than the QuickTime versions, but special software may need to be downloaded to open them (read the ÃÂHelpÃÂ page for details). Those people using public computers may be limited from fully accessing the resource. Mozilla Firefox users can view the VRML files directly in their browsers by downloading the Cortona extension (http://www.parallelgraphics.com/products/cortona/download/netscape/). This website is an excellent educational resource for all ages. The Virtual Insects home page (http://www.ento.vt.edu/~sharov/3d/3dinsect.html) has a basic explanation of how virtual reality works, including the Virtual Reality Modeling Language. The "Virtual Images" link takes you to a list of insects that can be viewed as 3D digital reconstructions. The image files would make excellent additions to teaching lectures for introductory classes. Visit the "How to Build Virtual Insects" page to read about how the images were created and how the original models were made more biologically accurate. Also be sure to read the page on how to view the cyber-insects inside a virtual reality "cave".

0002-11-30

77

Mesosiderites: A Chronologic and Petrologic Synthesis  

NASA Astrophysics Data System (ADS)

Recent petrologic, chemical, and isotopic analyses of mesosiderite clasts and whole rocks allow construction of the evolutionary history of the mesosiderite parent body (MPB) as shown in the figure. I. Initial Melting ~4.56 Ga Ago. Numerous chronologic measurements indicate that initial melting of the MPB occurred shortly after accretion, at about the same time that the eucrites and angrites formed. For example, a zircon grain from a basaltic clast in Vaca Muerta yielded a Pb-Pb age of 4.563 Ga (Ireland and Wlotzka, 1992). The 4.56-Ga event on the MPB is probably responsible for forming the monogenic basaltic clasts that compositionally resemble typical eucrites (Rubin and Mittlefehldt, 1992). II. Crustal Remelting ~4.47 Ga Ago. Internal Sm-Nd isochron ages of 4.47 Ga have been determined for gabbroic pebble 12 from Vaca Muerta and a basaltic clast from Mt. Padbury (Stewart et al., 1991). Pebble 12 is one of many clasts in mesosiderites that are highly depleted in incompatible elements and probably represent remelted crustal rocks (Rubin and Mittlefehldt, 1992). Because variation of Fe/Mn with Fe/Mg in pyroxenes from these clasts follows a trend defined by FeO reduction from a melt (Mittlefehldt, 1990), and because the reducing agents (e.g., P) were likely to have been introduced during metal-silicate mixing, the age of pebble 12 indicates that metal-silicate mixing had to have occurred >=4.47 Ga ago. III. Localized Impact Melting 4.5-3.9 Ga Ago. Localized impact melting and metamorphism were widespread on the eucrite parent body as indicated by many ages that were partially or totally reset <4.56 Ga ago. Impact melt material is common in mesosiderites of all petrologic types, and ages between 4.5-3.9 Ga are preserved. Quench-textured pebble 5 from Vaca Muerta, which is likely to have formed from a localized impact melt of material resembling a cumulate eucrite (Rubin and Jerde, 1987), has an internal isochron age of 4.42 Ga (Stewart et al., 1992). The high temperature of these localized events places them before the 3.9-Ga event (below); however, because no extensive crustal remelting is evident, the metamorphism must have occurred after 4.47 Ga ago. The mesosiderite breccias were assembled during this phase of MPB history. IV. Collisional Disruption and Reassembly ~3.9 Ga Ago. Mesosiderites were degassed by a major thermal event ~3.9 Ga ago that heated the rocks to ~500 degrees C; this event may mark collisional disruption and gravitational reassembly of the MPB (Bogard et al., 1990). The surface breccias were deeply buried at this time and heated somewhat above the Fe-Ni solvus, resetting the metallographic cooling rates to ~1 degree C/Ma. This event may also account for some of the reported disturbances in the Rb- Sr, Sm-Nd, and Pb-Pb ages of a few mesosiderites. V. Impact Excavation and Ejection <<3.9 Ga Ago. Mesosiderites have cosmic ray exposure ages ranging from ~10-150 Ma, which represent the epoch when individual mesosiderites were excavated from the MPB or from a >=10-m-size MPB fragment. References: Bogard D.D., Garrison D.H., Jordan J.L. and Mittlefehldt D. (1990) Geochim. Cosmochim. Acta 54, 2549-2564. Ireland T.R. and Wlotzka F. (1992) Earth Planet. Sci. Lett. 109, 1-10. Mittlefehldt D.W. (1990) Geochim. Cosmochim. Acta 54, 1165-1173. Rubin A.E. and Jerde E.A. (1987) Earth Planet. Sci. Lett. 84, 1-14. Rubin A.E. and Mittlefehldt D.W. (1992) Geochim. Cosmochim. Acta 56, 827-840. Stewart B.W., Cheng Q.C., Papanastassiou D.A. and Wasserburg G.J. (1991) Lunar Planet. Sci. (abstract) 22, 1333. Stewart B.W., Papanastassiou D.A. and Wasserburg G.J. (1992) Lunar Planet. Sci. (abstract) 23, 1365.

Rubin, A. E.; Mittlefehldt, D. W.

1992-07-01

78

Stereo Augmented Reality in the Surgical Microscope  

Microsoft Academic Search

This paper describes the MAGI (microscope-assisted guided interventions) augmented-reality system, which allows surgeons to view virtual features segmented from preoperative radiological images accurately overlaid in stereo in the optical path of a surgical microscope. The aim of the system is to enable the surgeon to see in the correct 3-D position the structures that are beneath the physical surface. The

Andrew P. King; Philip J. Edwards; Calvin R. Maurer Jr.; Darryl A. De Cunha; Ronald P. Gaston; Matthew J. Clarkson; Derek L. G. Hill; David J. Hawkes; Michael R. Fenlon; Anthony J. Strong; Tim C. S. Cox; Michael J. Gleeson

2000-01-01

79

Microscopic colitis.  

PubMed

As the diagnosis of microscopic colitis (MC) is made on the basis of histologic criteria, it is crucial to render an accurate microscopic interpretation. Features include 20 or more lymphocytes per 100 epithelial cells, mixed lamina propria inflammatory infiltrate, and preservation of crypt architecture for both lymphocytic and collagenous colitis (CC). CC is further characterized by a collagen band at least 10 mum thick. Although the pathogenesis of MC is poorly understood, medication-induced toxicity to the colonic mucosa is important to recognize, as medication cessation leads to prompt improvement. If MC is mild, symptomatic treatment is all that is needed, because some cases are self-limiting. Budesonide, 9 mg daily for at least 8 weeks, is the best documented treatment of choice for more severe or protracted cases. A 75% response rate has been reported; however, when treatment is discontinued, relapse is common, and longer-term tapering dose therapy often is necessary. There are disadvantages and no advantage to other forms of steroid therapy. Cholestyramine, bismuth, and 5-aminosalicylate derivatives appear to be less efficacious but are reasonable therapeutic options for less severe cases. Use of immunosuppressant therapy such as azathioprine or 6-mercaptopurine should be highly restricted because MC is a benign condition that does not result in other complications. Probiotic therapy with Lactobacillus acidophilus and Bifidobacterium animalis has not been shown to be effective in reducing bowel frequency. Surgical diversion of the fecal stream can control diarrhea and improve histology but is very rarely indicated and should be reserved for highly selected cases of severely symptomatic steroid-refractory MC. PMID:17547861

Stroehlein, John R

2007-06-01

80

Virtual Wonders  

NSDL National Science Digital Library

The British Natural History Museum has posted this site, which features a selection of fossils, meteorites, and other specimens that can be rotated and viewed in virtual reality. Each specimen is accompanied by a brief text description and links to additional information. This is a collection of strange and interesting virtual objects, most of which the viewer will not find in galleries. Virtual Wonders include a fossil ammonite, Anomalocaris model, Archaeopteryx skull, Coccolithopore, Radiolarian model, land snail shell, meteorite fragments, a two-faced sheep skull, fossil seashell, microfossil, specimen jar, surface of Mars, and trilobites.

81

A petrological view of early Earth geodynamics  

NASA Astrophysics Data System (ADS)

Xenoliths of low T Archean cratonic mantle consist mostly of harzburgite and lherzolite with geochemical depletions that are characterisitc of igneous residues. Many authors have identified the complementary magmas as komatiites. This model is re-examined in light of work presented in Herzberg & O'Hara (2002) and found to be problematic. Munro-type alumina-undepleted komatiites from Alexo, Pyke Hill, and other locations often contain olivine phenocrysts with maximum Mg# \\cong 94. Residues of fractional melting would consist of pure dunite having Mg# = 97-98, but these are not observed. Residues of equilibrium melting would also be pure dunite with Mg# = 94, but these are also not observed. Olivines with Mg# = 94 are found in rare harzburgites, indicating that residues of alumina-undepleted komatiite have either been overprinted by subsequent magmatism or they have been geodynamically eroded. Alumina-undepleted komatiites can be successfully modeled with a primary magma containing 30% MgO produced by 0.5 mass fractions of equilibrium melting of depleted peridotite. A hot plume interpretation is consistent with both the petrology and helium isotopic compositions of alumina-undepleted komatiites. But what about cratonic mantle? The FeO and MgO contents of residues of fertile mantle peridotite formed by both equilibrium and fractional melting can be predicted and applied to xenoliths of cratonic mantle in most cases. Application to xenoliths from the Kaapvaal and Slave cratons is not possible owing to a second stage of Opx enrichment, but results can be applied to most xenoliths from Siberia, Tanzania, Somerset Island, and east Greenland as they contain less than 45% SiO_2. These xenoliths are very similar to residues produced by fractional melting. Pressures of initial melting were mostly 3 to 5 GPa, but can be as high 7 GPa. Pressures of final melting were highly variable and can be as low as 1 GPa. Potential temperatures (T_P) were typically 1450 to 1600oC and primary magmas contained 14 to 22% MgO, similar to Reykjanes MORB, Gorgona, Hawaii, and the early Icelandic plume in the model of Herzberg & O'Hara (2002). However, a few xenoliths record T_P as low as 1300oC. Two geodynamic interpretations follow: 1) Archean cratonic mantle formed as residues below ridges and hotspots similar to those of today, except the lithosphere was somewhat thinner in some cases, 2) Archean cratonic mantle formed as residues below hot ridges in most cases. Early Proterozoic sheeted dikes and eruptives from the Cape Smith Belt in Canada are consistent with the hot ridge interpretation. Ridge potential temperatures could have been 1520-1570oC, higher than modern ridges (1300-1450oC) but similar to those for the Gorgona and early Tertiary Icelandic plumes.

Herzberg, C.

2003-04-01

82

Virtual Environments, Virtual Works, Virtual Lives?  

Microsoft Academic Search

Technological advances mostly in Internet and mobile technologies affect our lives in myriad ways. Globally, these technologies are used in many environments; the usage of these technologies also creates virtual environments. The concepts of time, place, language and boundaries disappear; many people from different countries and cultures can communicate with each other and work together. However, besides its benefits, working

Gonca Telli Yamamoto; Ali Telli; Michael Featherstone; Patricia Borstoff

2006-01-01

83

Virtual colonoscopy  

MedlinePLUS

Colonoscopy - virtual; CT colonography ... table that is connected to an MRI or CT scan machine. Your knees will be up toward ... can take, and which you should temporarily stop. CT and MRI scanners are very sensitive to metals. ...

84

Virtual City  

NSDL National Science Digital Library

In conjunction with Rice Design Alliance's Virtual City lecture series held earlier this year, home pages have been put up for two of the speakers, Howard Rheingold and Bruce Sterling, with access to online writings included.

1994-01-01

85

Virtual Dating  

NSDL National Science Digital Library

This is an interactive exercise about Geologic Time. It focuses on how geologists and archaeologists determine the ages of rocks and ancient artifacts. This is a beta release of an instructional activity still under development. Virtual Dating contains two modules as well as a demonstration version. One module is Virtual Dating Isochron for rocks and minerals and the other is Virtual Dating Radiocarbon (Carbon-14). The interactive modules involve the students in exploring data and background information and answering questions as they move through the activity. An answer checking and feedback function is employed. There is also a Virtual Dating Demo if you want to do a quick run-through of the activity without answer checking enabled.

Novak, Gary

1999-04-01

86

Tele-nanorobotics using atomic force microscope  

Microsoft Academic Search

A tele-nanorobotics system using an atomic force microscope (AFM) as the nanorobot has been proposed. Modeling and control of the AFM cantilever, and modeling of nanometer scale forces have been realized for telemanipulation applications. Besides 3-D virtual reality visual feedback in the user interface, a 1 DOF haptic device has been constructed for nano scale haptic sensing. For feeling the

Metin Sitti; Hideki Hashimoto

1998-01-01

87

Virtual Specimens  

NASA Astrophysics Data System (ADS)

Virtual Field Trips have been around almost as long as the Worldwide Web itself yet virtual explorers do not generally return to their desktops with folders full of virtual hand specimens. Collection of real specimens on fields trips for later analysis in the lab (or at least in the pub) has been an important part of classical field geoscience education and research for generations but concern for the landscape and for preservation of key outcrops from wanton destruction has lead to many restrictions. One of the author’s favorite outcrops was recently vandalized presumably by a geologist who felt the need to bash some of the world’s most spectacular buckle folds with a rock sledge. It is not surprising, therefore, that geologists sometimes leave fragile localities out of field trip itineraries. Once analyzed, most specimens repose in drawers or bins, never to be seen again. Some end up in teaching collections but recent pedagogical research shows that undergraduate students have difficulty relating specimens both to their collection location and ultimate provenance in the lithosphere. Virtual specimens can be created using 3D modeling software and imported into virtual globes such as Google Earth (GE) where, they may be linked to virtual field trip stops or restored to their source localities on the paleo-globe. Sensitive localities may be protected by placemark approximation. The GE application program interface (API) has a distinct advantage over the stand-alone GE application when it comes to viewing and manipulating virtual specimens. When instances of the virtual globe are embedded in web pages using the GE plug-in, Collada models of specimens can be manipulated with javascript controls residing in the enclosing HTML, permitting specimens to be magnified, rotated in 3D, and sliced. Associated analytical data may be linked into javascript and localities for comparison at various points on the globe referenced by ‘fetching’ KML. Virtual specimens open up new possibilities for distance learning, where design of effective lab exercises has long been an issue, and they permit independent evaluation of published field research by reviewers who do not have access to the physical field area. Although their creation can be labor intensive, the benefits of virtual specimens for education and research are potentially great. Interactive 3D Specimen of Sierra Granodiorite at Outcrop Location

de Paor, D. G.

2009-12-01

88

Volcanology and petrology of the Assab Range (Ethiopia)  

Microsoft Academic Search

The results of petrological and volcanological investigations of the Assab area (Ethiopia) are reported. Fissure activity\\u000a — which produced basaltic lava flows and several spatter cones — and central activity — represented by a cumulus dome and\\u000a two explosive craters — have been recognized.\\u000a \\u000a The area is characterized by E-W and NE-SW tectonic trends, whereas the NNW-SSE Eritrean trend is

M. De Fino; L. La Volpe; L. Lirer

1973-01-01

89

Petrology, mineralogy, and geochemistry of lignites from Crete, Greece  

Microsoft Academic Search

Coal from the deposit of Plakia, Island of Crete, Greece, was examined petrologically for the determination of rank, maceral composition, and trace element geochemistry. The coal is of lignite to subbituminous B rank (%Ro,ran = 0.36-0.44). Some samples are rich in resinite. This was subdivided into two groups based on its morphological and fluorescence properties. Mineral matter in the coals

Thomas Gentzis; Fariborz Goodarzi; Constantinos N. Koukouzas; Anthony E. Foscolos

1996-01-01

90

Biological marker geochemistry and organic petrology of Chattanooga shale  

SciTech Connect

The Upper Devonian Chattanooga Shale is an extremely organic-rich unit containing up to 13% organic carbon, thus making it an important potential oil shale and/or petroleum source rock. Samples of the Chattanooga Shale from the periphery of the Nashville dome in central Tennessee and south-central Kentucky have been examined and grouped by maturity and organofacies, using biological marker geochemistry of extractable bitumen and organic petrology.

Adams, J.P.; Kruge, M.A.; Bensley, D.F. (Southern Illinois Univ., Carbondale (USA))

1989-08-01

91

Virtual Museums and Virtual Realities  

Microsoft Academic Search

The notion of virtual museum is discussed and related to various developments in user-interface, software, and communications technology. A prototype implementation, intended to explore the integration of interactive 3d graphics with video imagery is described.

Dennis Tsichritzis; Simon J. Gibbs

1991-01-01

92

Exploration petrology of Sunoco Felda trend of south Florida  

SciTech Connect

The Sunoco Felda oil trend of the South Florida basin has been a prolific oil producer. All the oil is produced from the Cretaceous Sunniland formation, a leached limestone bioherm. Although the producing section has been considered reefal in the literature, petrographic and biostratigraphic analyses of various cores in producing fields have determined that these deposits are composed of particles of fragmented rudist and other fauna deposited in a tidal shoal. Atop this debris an algae and gastropod section has been deposited, typical of a mound deposited on a tidal mud flat. This model is exemplified in the Sunoco Felda and West Sunoco fields and was used in exploring the Sunoco Felda trend. From the petrological analysis of these two fields and from knowledge of other wells in the basin, biostratigraphic and lithologic trends can be determined and extended offshore into the eastern Gulf of Mexico. The author stresses petrology in exploring the Sunniland formation because correlating like responses on electric logs does not always result in correlating the same depositional facies - in fact, correlating like electric log responses in the Sunniland formation often results in correlating different facies. This study endeavors to analyze the Felda trend based on the petrological and petrophysical information obtained from the cores and logs. The author will show that the potential of the Sunniland formation may be greater than expected and that it may be the site of future major discoveries.

Mitchell-Tapping, H.

1986-09-01

93

Community and Virtual Community.  

ERIC Educational Resources Information Center

|Presents a literature review that covers the following topics related to virtual communities: (1) information and virtual community; (2) virtual communities and communities of practice; (3) virtual communities and virtual arenas, including virtual community networks; and (4) networked virtual communities. (Contains 175 references.) (MES)|

Ellis, David; Oldridge, Rachel; Vasconcelos, Ana

2004-01-01

94

Virtual Vision  

NASA Astrophysics Data System (ADS)

Computer vision and sensor networks researchers are increasingly motivated to investigate complex multi-camera sensing and control issues that arise in the automatic visual surveillance of extensive, highly populated public spaces such as airports and train stations. However, they often encounter serious impediments to deploying and experimenting with large-scale physical camera networks in such real-world environments. We propose an alternative approach called "Virtual Vision", which facilitates this type of research through the virtual reality simulation of populated urban spaces, camera sensor networks, and computer vision on commodity computers. We demonstrate the usefulness of our approach by developing two highly automated surveillance systems comprising passive and active pan/tilt/zoom cameras that are deployed in a virtual train station environment populated by autonomous, lifelike virtual pedestrians. The easily reconfigurable virtual cameras distributed in this environment generate synthetic video feeds that emulate those acquired by real surveillance cameras monitoring public spaces. The novel multi-camera control strategies that we describe enable the cameras to collaborate in persistently observing pedestrians of interest and in acquiring close-up videos of pedestrians in designated areas.

Terzopoulos, Demetri; Qureshi, Faisal Z.

95

Virtual Classroom with Intelligent Virtual Tutor  

Microsoft Academic Search

In order to improve the educational function of e-learning, a virtual classroom with intelligent virtual tutor has been developed. Architecture of the virtual classroom system is presented. The intelligent virtual tutor can perceive environment and make its own decision to enhance the interaction between tutor and remote students in some degree. The virtual tutor is emotive, which can help remote

Yan Hu; Gang Zhao

2010-01-01

96

Virtual Tower  

SciTech Connect

The primary responsibility of an intrusion detection system (IDS) operator is to monitor the system, assess alarms, and summon and coordinate the response team when a threat is acknowledged. The tools currently provided to the operator are somewhat limited: monitors must be switched, keystrokes must be entered to call up intrusion sensor data, and communication with the response force must be maintained. The Virtual tower is an operator interface assembled from low-cost commercial-off-the-shelf hardware and software; it enables large amounts of data to be displayed in a virtual manner that provides instant recognition for the operator and increases assessment accuracy in alarm annunciator and control systems. This is accomplished by correlating and fusing the data into a 360-degree visual representation that employs color, auxiliary attributes, video, and directional audio to prompt the operator. The Virtual Tower would be a valuable low-cost enhancement to existing systems.

Wayne, R.A. [Sandia National Labs., Albuquerque, NM (United States). Security Engineering Dept.

1997-08-01

97

Virtual Hospital  

NSDL National Science Digital Library

Provided and maintained by the University of Iowa Health Care, the Virtual Hospital is designed as a "medical reference and health promotion tool for health care providers and patients." To that end, the site offers current and authoritative medical information for patients and professional and pedagogical information for health care providers. The former includes patient educational briefs browseable by organ system or by a topical list, a collection of peer-reviewed and annotated Web resources, an internal search engine, and archives of a column offering medical advice to middle-aged users. Resources in the health care provider section include several digital libraries aimed at certain specialties (Pediatrics, Pediatric Radiology, Family Medicine, and Medical Student); multimedia textbooks and teaching files grouped by organ system; lectures and publications; and clinical practice guidelines. Additional resources at the site include links to the Virtual Children's and Virtual Naval Hospitals, an internal search engine, and online continuing education courses.

1999-01-01

98

Virtual Labs  

NSDL National Science Digital Library

These virtual labs from the Howard Hughes Medical Institute allow students to experience laboratory procedures as if they were a professional scientist. Students can isolate and analyze bacterial DNA sequences, examine cardiac patients, dissect a leech, or diagnose diseases by detecting the presence of antibodies. These virtual labs include animated steps that must be performed, along with textual instructions and explanations so that students understand not only what they are doing, but also why they are doing it. This is an extensive Web site that offers a lot to learn, and a chance to have fun in the process.

1969-12-31

99

Application of Automated SEM-EDS Based Mineral Identification Systems to Problems in Metamorphic Petrology  

NASA Astrophysics Data System (ADS)

Automated scanning electron microscopy-energy dispersive x-ray spectrometer (SEM-EDS) based mineral identification systems such as QEMSCAN have been in development for over 20 years, primarily as a tool to understand mineral liberation and element distribution in metal mining industry. This powerful technique is now being used in non mining applications such as metamorphic petrology where accurate mineral identification and metamorphic fabrics are key to deciphering the metamorphic history of samples. The QEMSCAN was developed by CSIRO for application in the mining industry where it is used to understand mineralogy, texture, mineral associations, the presence of gangue minerals and deleterious elements that may potentially interfere with mineral processing and planning, and the overall impact of mineralogy on grinding and flotation processes. It is capable of identifying most rock-forming minerals in milliseconds from their characteristic x-ray spectra. The collected x-ray spectra are compared to entries in a database containing the species identification profiles (SIPs) and are assigned a label accordingly. QEMSCAN is capable of searching large sample areas at high resolution resulting in the accurate and precise determination of all minerals present. Reports that were originally developed for the mining geologist can be equally useful to the petrologist, e.g. phase/mineral maps, modal mineral abundances and mineral association reports. Identification of key minerals is of great importance to determining the petrologic history of a sample. These key minerals may be few in number and present as small microinclusions (less than 100 ?m) making them difficult to identify, if at all, with the petrographic microscope. Therefore, imaging by electron-microprobe or scanning electron microscope are the methods traditionally used. However, because of the small field of view available on these instruments at a magnification necessary to resolve micron sized relicts and textures, the search for a few microinclusions may be extremely time consuming, tedious and costly. QEMSCAN with its ability to provide large quantitative data sets and search large sample areas at high resolution means that whole thin sections can have their mineralogy accurately and precisely determined in hours. For instance in metamorphic petrology once relict minerals of earlier metamorphic assemblages are located; thermobarometry and geochronology can then be applied; resulting in a wealth of information on previous segments of the pressure-temperature-time-deformation path. The relict mineral textures and their relationship to the fabric of the entire thin section can be easily seen in the phase/mineral map yielding important textural information. We have developed a SIP database to be used to study metamorphic samples from the Central Metamorphic terrane (CMt) of the eastern Klamath Mountains, northern California. The CMt was chosen because recent work has resulted in the discovery of relict rutile grains and ilmenite-plagioclase-amphibole symplectites textures interpreted as the decomposition of either garnet or omphacite during exhumation from eclogite facies conditions. The QEMSCAN is being used primarily to search for these relict garnet and omphacite grains. Although only a few samples have been run, no garnet or omphacite have been located thus far. However, in a very short period of time the modal mineral abundances and overall fabric have been determined to a degree never previously achieved.

Fairhurst, Robert; Barrow, Wendy; Rollinson, Gavyn

2010-05-01

100

The virtual blood film.  

PubMed

The computer and the digital camera offer unprecedented possibilities for improving hematology education, research, and patient service. Peripheral blood smear images of exceptional quality can be acquired rapidly and conveniently from the peripheral blood smear with a modern, high-resolution digital camera and a quality microscope. Digital cameras use CCD or CMOS image sensors to measure light energy and additional circuitry to convert the measured information into a digital signal. Because digital cameras do not use photographic film, images are immediately available for incorporation into web sites or digital publications, printing, transfer to other individuals by e-mail, or other applications. Several excellent consumer digital still cameras are now available for less than $1000 that capture high-quality images comprised of more than three megapixels. These images are essentially indistinguishable from conventional film images when viewed on a quality color monitor or printed on a quality color or black and white printer at sizes up to 8 x 10 in. Several recent dedicated digital photomicroscopy cameras provide an ultrahigh quality image output of more than 12 megapixels and have low noise circuit designs permitting the direct capture of darkfield and fluorescence images. There are many applications of digital images of peripheral blood smears. Because hematology is a visual science, the inclusion of quality digital images into lectures, teaching handouts, and electronic documents is essential. A few institutions have gone beyond the basic application of digital images to develop large electronic hematology atlases; animated, audio-enhanced learning experiences; multidisciplinary Internet conferences; and other innovative applications. Digital images of single microscopic fields (single-frame images) are the most widely used in hematology education at this time, but single images of many adjacent microscopic fields can be stitched together to prepare zoomable panoramas that encompass a large part of a microscope slide and closely stimulate observation through a real microscope. With further advances in computer speed and Internet streaming technology, the virtual microscope could easily replace the real microscope in pathology education. Interactive, immersive computer experiences may completely revolutionize hematology education and make the conventional lecture and laboratory format obsolete later in this decade. Patient care is enhanced by the transmission of digital images to other individuals for consultation and education, and by the inclusion of these images in patient care documents. In research laboratories, digital cameras are widely used to document experimental results and obtain experimental data. PMID:11933581

Riley, Roger S; Ben-Ezra, Jonathan M; Massey, Davis; Cousar, John

2002-03-01

101

Organic petrology in the 19th, 20th, and 21st centuries: The Newcastle contribution  

Microsoft Academic Search

The paper describes the development of coal petrology, then organic petrology, over a period of approximately 175 years around and in Newcastle upon Tyne (England). From 1833 until 1950, the basis of study was essentially transmitted light microscopy. In this period, perhaps the supreme contribution was the work of Hutton, Lindley, and Witham, who demonstrated the vegetable nature of coal

Duncan Murchison

2005-01-01

102

Teaching Petrology in the 21st Century: A Workshop Report and Call to Action  

Microsoft Academic Search

Petrology plays an important role in the upper division geology curriculum, introducing students to the skills needed to investigate and interpret igneous and metamorphic rocks that form the bulk of the earth's interior. Central concepts in petrology courses typically include chemical differentiation of Earth, the role of igneous and metamorphic processes in the Earth system, and the occurrences and distribution

D. Mogk; C. Davidson; C. Manduca; J. Braday

2003-01-01

103

Blending Curriculum with Research in an Undergraduate Petrology Course: A Recipe for Success?  

Microsoft Academic Search

In this presentation we discuss the design, key curricular elements, and strengths and weaknesses of an undergraduate course in the Department of Geosciences at Fort Lewis College that was recast to focus on petrologic studies in the Southern Rocky Mountains and Colorado Plateau. Redesign of the course retained an additional petrology option in the curriculum and offered undergraduates a richer

D. A. Gonzales; S. C. Semken

2009-01-01

104

VIRTUAL CONSUMERISM  

Microsoft Academic Search

Selling virtual items for real money is increasingly being used as a revenue model in games and other online services. To some parents and authorities, this has been a shock: previously innocuous ‘consumption games’ suddenly seem to be enticing players into giving away their money for nothing. In this article, we examine the phenomenon from a sociological perspective, aiming to

Vili Lehdonvirta; Terhi-Anna Wilska; Mikael Johnson

2009-01-01

105

Virtual colonoscopy  

Microsoft Academic Search

Virtual colonscopy (VC) is an evolving technique that combines volume scanning and computer visualization methods to enable minimally invasive and effective colorectal cancer screening. Although VC offers significant clinical and public health advantages over conventional endoscopic screening, several issues confront VC's emergence into the medical marketplace.

David J Vining

1999-01-01

106

Virtual Parentalism  

Microsoft Academic Search

Parents, not Laws, ultimately protect children both online and offline. If legislation places adults at legal risk because of the presence of children in virtual worlds, adults will exit those worlds, and children will be isolated into separate spaces. This will not improve safety for children. Instead, this Article suggests that Congress enact measures that encourage filtering technology and parental

Joshua A. T. Fairfield

2009-01-01

107

Virtual Skies  

NSDL National Science Digital Library

Produced by NASA for use in high schools and flight technology programs, Virtual Skies explores the worlds of aviation technology, air traffic management, and current research. The site includes information on aeronautics, navigation, weather, air traffic management, communications, airport design and related careers.

Conrad, Linda

2011-09-22

108

Virtualize Me!  

ERIC Educational Resources Information Center

|John Abdelmalak, director of technology for the School District of the Chathams, was pretty sure it was time to jump on the virtualization bandwagon last year when he invited Dell to conduct a readiness assessment of his district's servers. When he saw just how little of their capacity was being used, he lost all doubt. Abdelmalak is one of many…

Waters, John K.

2009-01-01

109

Virtual Reality.  

ERIC Educational Resources Information Center

Discusses the current state of the art in virtual reality (VR), its historical background, and future possibilities. Highlights include applications in medicine, art and entertainment, science, business, and telerobotics; and VR for information science, including graphical display of bibliographic data, libraries and books, and cyberspace.…

Newby, Gregory B.

1993-01-01

110

Virtual Schooling  

ERIC Educational Resources Information Center

Virtual schooling, in which K-12 courses and activities are offered mostly or completely through digital communication technologies, has become firmly established in K-12 education across the United States. The VS movement continues to expand at a rapid rate, especially at the high school level. The continuing success of VS efforts will require…

Davis, Niki; Niederhauser, Dale S.

2007-01-01

111

Personal Virtual Libraries  

ERIC Educational Resources Information Center

|Virtual libraries are becoming more and more common. Most states have a virtual library. A growing number of public libraries have a virtual presence on the Web. Virtual libraries are a growing addition to school library media collections. The next logical step would be personal virtual libraries. A personal virtual library (PVL) is a collection…

Pappas, Marjorie L.

2004-01-01

112

Enhanced virtual microscopy for collaborative education  

Microsoft Academic Search

BACKGROUND: Curricular reform efforts and a desire to use novel educational strategies that foster student collaboration are challenging the traditional microscope-based teaching of histology. Computer-based histology teaching tools and Virtual Microscopes (VM), computer-based digital slide viewers, have been shown to be effective and efficient educational strategies. We developed an open-source VM system based on the Google Maps engine to transform

Marc M Triola; William J Holloway

2011-01-01

113

Geochemical and petrological observations of gas transport at arc volcanoes  

NASA Astrophysics Data System (ADS)

Understanding the abundance and composition of vapour in magma chambers and the mechanisms of vapour transport in volcanic systems is of immense importance. Exsolved vapour in a magma storage area affects eruption style and duration, and influences ground deformation and other geophysical manifestations owing to its compressibility. Ultimately, we wish to understand how much pre-eruptive exsolved vapour exists and what role mafic magma supply at depth plays in supplying it. Soufriere Hills Volcano, Montserrat, has become an exceptionally well-monitored volcanic system and there is now an abundance of detailed geochemical and petrological information regarding magma degassing and gas transport processes. The eruption provides a unique opportunity to study the effects of open system mafic magma injection, mingling and degassing, which is occurring on the same time scale as eruption. We examine the geochemical and petrological evidence for magma mingling, degassing and gas fluxing at Soufriere Hills Volcano. We use measurements of gas flux and composition, using DOAS and a multigas sensor. We examine petrological and textural evidence for mafic magma supplying volatiles to the system, including evidence from phenocryst zoning and composition. We show that the mafic magma supplies volatiles as well as heat to the overlying resident andesite. Due to the strong partitioning of sulphur into a vapour phase at depth under oxidising conditions, the sulphur dissolved in the intruding mafic magma becomes segregated into vapour, along with carbon dioxide and water. The vapour is transported to the surface during both eruptive and non-eruptive periods, implying either that significant permeability exists within the system, or that magma convection operates. There is some evidence for gas fluxing, which suggests that gas may be transported through the magma. We draw comparisons with other recent studies of volatile transport in arc systems to show that some observations may be generic.

Edmonds, M.; Herd, R. A.; Humphreys, M.; Aiuppa, A.; Giudice, G.; Guida, R.; Moretti, R.; Christopher, T. E.; Rawson, H.

2010-12-01

114

Fluorescence spectroscopy: A promising tool for carbonate petrology  

SciTech Connect

Responses of depositional and diagenetic components in samples of the Mission Canyon Limestone to blue-light excitation vary most noticeably with mineralogy and crystal size. The finely crystalline micrites, dolomicrites and argillaceous carbonates fluoresce more intensely than the more coarsely crystalline sparry calcite cements, dolospar cements and coarsely crystalline dolomites. Low intensity spectral analysis of cherts, anhydrites, and the carbonate phases provides an objective manner for quantifying fluorescence responses and for comparing them statistically. Nineteen of the optical parameters used in organic petrology are evaluated for their utility in carbonate petrology. Results of the discriminant function analysis suggest that red-weighted fluorescence chromaticity indices and yellow-weighted ones are more useful for mineral identification than the blue-weighted or equal-energy chromaticity indices. Statistical analysis of the optical data, mineralogy, and minor element compositions suggests correlations between the fluorescence responses and major minerals, carbonate diagenetic components, and the minor element geochemistry of carbonate components. Although no single element is identified as an activator of fluorescence in this study, the complex correlations of optical indices with Fe suggest that it does act to quench fluorescence. The four fluorescence cy chromaticity indices correlate significantly and positively with mineralogy and negatively with MgCo[sub 3]. In organic petrology, these indices are related to maceral content. The positive correlations of the four fluorescence cx chromaticity indices with Fe and Mn likely reflect fluorescence response to changes in compositions of pore fluids during diagenesis. This trend parallels the increase in cx indices with increasing maturation of organic materials.

Vice, M.A.; Bensley, D.F.; Utgaard, J.E. (Southern Illinois Univ., Carbondale, IL (United States). Dept. of Geology)

1992-01-01

115

CHI_PET: Computerized hierarchical indexing of petrological information  

NASA Astrophysics Data System (ADS)

CHI_PET is a utility, written in DbaseIV programming language, which indexes petrological and geological information in a database. The process is completely automatic and computer driven, making a comprehensive search of free-text fields for geological information, testing for 10,500 petrological and geological terms contained in current geological dictionaries. The utility uses a hierarchical index structure which has 369 components representing major headings and subheadings within the index structure given in Tomkeieff's "Dictionary of Petrology". The hierarchical structure is significant because it allows for synonymous scientific terms and provides for the recognition of subset relations. The free-text fields are treated with a record-optimized search/match procedure, with successful index strikes accumulated up the hierarchical structure. Dead words such as 'and, the' and nonsignificant characters such as ' + - /' are ignored. The process generates an index vector which shows the geological composition of each record. A database for a Rock Collection of 50,000 rocks was indexed at a rate of 2500 records per hour. An equivalent geological index would have required years of work to prepare manually. The CHI_PET process is convenient to use, and the resultant index vector also is easy to address, update, and use for retrieval. Output uses of the index vectors include: ad hoc reports for rocks that pass a selection sieve of specified index categories; an index for a suite of rocks; pseudocluster diagrams showing the index composition for a suite of rocks. A layout of the enhanced index structure is given, along with listings of the Dbase programs, and samples of output products. With minor modification to the CHI_PET utility, any hierarchical structure of index terms can be used to index free text fields in databases.

Barron, L. M.

1993-08-01

116

Mineralogic and petrologic studies of meteorites and lunar samples  

NASA Astrophysics Data System (ADS)

During a 13 year period beginning in 1971, the Extraterrestrial Petrology Group examined lunar soils from all 6 Apollo missions and those returned by the Soviet Luna 16, Luna 20, and Luna 24 missions. In addition, the properties and apparent origin of the carbonaceous chondrites were examined. Chondrules, calcium-aluminum-rich inclusions (CAI) and the fine grained matrix materials that accompany chondrules and CAI's in primitive meteorites were investigated. The effects of planetary hydrothermal alteration of matrix materials in the C1 chondrite was also investigated. Full length papers and extended abstracts published during the grant are listed chronologically.

Wood, J. A.

1984-03-01

117

Magnetic petrology of deep crustal rocks-Ivrea Zone, Italy  

NASA Astrophysics Data System (ADS)

Magnetic petrology is an extension of petrology, integrating magnetic property studies with conventional petrology for the purpose of understanding the development and modification of the magnetization in rocks. The magnetic properties of a suite of samples from the Ivrea Zone, northern Italy, are described with the aim of developing a magnetic petrology for deep crustal rocks. Samples studied include a variety of metamorphosed mafic (granulites, granofelses, plagioklasfelse, amphibolite, pyriclasite) and pelitic/quartzo-feldspathic rocks (acid granulites, stronalite and kinzigite gneisses, schists), and representative ultramafic rocks (phlogopite peridotite, pyroxenite, hornblendite). Ilmenite is the chief oxide mineral in a majority of the samples, but in a few mafic rocks, magnetite is the principal oxide constituent. Cr,Al-spinel is common in ultramafic samples and rutile is present in some metapelites. Sulfides are generally subordinate in abundance to oxide minerals. The mafic rocks in the Ivrea section have the broadest range of magnetic properties and include the most strongly magnetic samples. The Ivrea ultramafic rocks are moderately magnetic-the magnetite present appears to be secondary and is associated with crustal alterations-while pelitic and quartzo-feldspathic lithologies are dominantly paramagnetic or only weakly magnetic. The main ferromagnetic mineral in all strongly magnetic samples is magnetite that is nearly pure Fe3O4 in composition. Consequently, Curie temperatures are 565-580°C for these rocks. Pyrrhotite contributes to the magnetism in several ultramafic and mafic rocks, and it is the sole ferromagnetic mineral in the pelitic and quartzo-feldspathic samples. The results of our study indicate that certain mafic rock types (amphibolites, mafic granulites, pyriclasites) are the most likely source of the Ivrea Zone's regional scale magnetic anomalies. If the Ivrea Zone represents a tectonically exposed cross section of continental crust, the geographic distribution of these rock types suggests the presence of multiple and variably thick, strongly magnetic layers, with magnetite Curie temperatures, in the deep crust. Petrographic evidence suggests, however, that the magnetic mineralogy of the sampled Ivrea rocks might have been changed subsequent to peak metamorphic conditions. Therefore, considerable care must be taken in evaluating the magnetic record in these crustal cross sections, particularly if they are to be used to model the magnetic characteristics of the lower crust.

Wasilewski, Peter; Warner, Richard D.

1988-02-01

118

University of Minnesota Structure Tectonics and Metamorphic Petrology Research Group  

NSDL National Science Digital Library

The University of Minnesota Structure Tectonics and Metamorphic Petrology Research Group describes its research on the deformation of continental lithosphere at this website. Users can find clear explanations of the group's current projects including partial melting and orogeny, continental subduction, and shear zones. Students and scientists can find the research interests and a list of publications for the group's faculty, research associates, and students. The website displays the group's analytical, field, and teaching equipment as well as its Institute for Rock Magnetism and Characterization Facility.

2005-11-02

119

Virtual Autopsy  

NSDL National Science Digital Library

Designed with medical students in mind, Leicester (England) University's Virtual Autopsy site takes the student on a virtual tour of seven autopsies. Several options allow for efficient navigation of the site: Cause of Death is a self-assessment quiz students may take after "performing" each autopsy; Return to History takes the user back to the beginning of each case; and Choose another Case lets the user move between the seven cases. Each case contains nearly a dozen detailed color images of certain key parts (including tissues) of the human anatomy--lung, body, heart, head--with hyperlinks to further information. By clicking on the dictionary icon, for instance, a student links to a pop-up page with detailed descriptions of that particular condition. Aspiring pathologists are sure to find this worthwhile, and the absence of gruesome images makes it a good learning site for many budding medical scientists as well.

2000-01-01

120

Structuring Virtuality  

Microsoft Academic Search

The purpose of this paper is to provide an example of an empirical procedure for generating user-based cognitive and social\\u000a cognitive models of tasks\\/problems\\/contexts that can be employed to create readily navigable link structures for virtuality-mediated\\u000a communication and collaboration purposes. Employing a natural language, user-based method, this study describes patterns found\\u000a across 128 interviews where respondents were describing their cognitive

Michael Sanford Nilan; Anuradha Mundkur

2007-01-01

121

Virtual Dice  

NSDL National Science Digital Library

This interactive Flash applet contains a set of four virtual dice with 6, 8, 10 and 12 faces. Clicking a chosen die generates a random value. The values on each die can be customized with the user's own choices to provide flexibility. These values can be up to five digits long and include either positive, negative or a combination of numbers, and can include text or symbols. The dice can be used to generate random numbers in game situations or in studying probability.

Services, Bbc O.

2012-01-01

122

Virtual Mirrors  

NASA Astrophysics Data System (ADS)

The multiple-reflection photograph in Fig. 1 was taken in an elevator on board the cruise ship Norwegian Jade in March 2008. Three of the four walls of the elevator were mirrored, allowing me to see the combination of two standard arrangements of plane mirrors: two mirrors set at 90° to each other and two parallel mirrors. Optical phenomena of this complexity are most easily approached by the Method of Virtual Mirrors.1

Greenslade, Thomas B.

2010-01-01

123

VIRTUAL BUSINESS  

Microsoft Academic Search

The Seattleites who dug deep on their pockets to try out Virtual reality at the Video Tech Pavilion during Bumbershoot '92 walked away reeling from the imaginative, futuristic possibilities of the technology. In fact, the experience of dipping one senses into a three-dimensional computer graphics world had already found an appeal within the radical-chic cyberculture led by '60s icon Timothy

Julian C. Bleecker

1993-01-01

124

Virtual Sojourner  

NSDL National Science Digital Library

This module has students carry out a virtual Mars mission similar to Pathfinder's rover, the Sojourner. Students work in teams, concentrating on specific mission needs, such as engineering, camera, navigation, or science. The activities in this module simulate the Mars Pathfinder mission objectives and structure. The purpose of this module is for students to work collaboratively to map, invent, and solve navigation problems with a 'remote' classroom.

Edgerton, Richard; Tillman, James

125

Virtual Geoengineer  

NSDL National Science Digital Library

The site presents specific topics in geoengineering practice through photos, maps, diagrams, and videos using texts. Materials found in the Virtual Geoengineer include: photos with details of projects, case histories, photos of different construction methods with explanations and equipment used in construction, and construction issues on specific projects. Topics covered include: geology, earthquake engineering, foundations, excavation, in-situ testing, dams, geosynthetics, landslides, and slope failures.

2008-09-23

126

Autonomous Virtual Actors Based on Virtual Sensors  

Microsoft Academic Search

In this paper, we present current research developments in the Virtual Life of autonomous synthetic actors. After a brief description of the perception action principles with a few simple examples, we emphasize the concept of virtual sensors for virtual humans. In particular, we describe in details our experiences in implementing virtual vision, tactile and audition. We then describe perception-based locomotion,

Daniel Thalmann; Hansrudi Noser; Zhiyong Huang

1997-01-01

127

Igneous and metamorphic petrology in the field: a problem-based, writing-intensive alternative to traditional classroom petrology  

NASA Astrophysics Data System (ADS)

The Geology Department at Western Washington University (~100 geology majors) offers field and classroom versions of its undergraduate petrology course. This is a one-quarter course (igneous and metamorphic petrology) with mineralogy as a prerequisite. The field version of the course is offered during the three weeks prior to fall quarter and the classroom version is offered in spring quarter. We take 15-20 students around the state of Washington, camping at different outcrop sites where students integrate observational skills, petrologic knowledge, and writing. Petrogenetic associations in various tectonic settings provide the theme of the course. We compare ophiolites vs. arc sequences (volcanic, plutonic, and metamorphic rocks), S- vs. I-type granitoids (plutonic rocks and associated metamorphic rocks), Barrovian vs. Buchan vs. subduction zone metamorphism of different protoliths, and flood-basalt vs. active-arc volcanism. Some basics are covered in the first day at WWU, followed by 17 days of field instruction. Lecture is integrated with outcrop study in the field. For example, students will listen to a lecture about magma differentiation processes as they examine cumulate rocks in the Mt. Stuart batholith, and a lecture about metamorphic facies as they study blueschist facies rocks in the San Juan Islands. Students study multiple outcrops around a site for 1-4 days. They then use their observations (sketches and written descriptions of mineral assemblages, rock types, rock textures, etc.) and analysis techniques (e.g. geochemical data plotting, metamorphic protolith analysis) to write papers in which the data are interpreted in terms of a larger tectonic problem. In advance of the writing process, students use group discussion techniques such as whiteboarding to share their observational evidence and explore interpretations. Student evaluations indicate that despite the intense pace of the course, they enjoy it more. Students also feel that they retain more material for future classes. The undivided attention, immediate writing/reflection, and repetition of skills in different settings reinforce material. Because of students' higher level of engagement, more of them pursue advanced classes or independent studies. A corollary benefit is that students form strong bonds with their cohort group, providing mutual support as they continue through the program and ultimately improving their field camp experience. Final exam scores are equal to or better than in the traditional class, and some basic skills, such the ability to make observations at a variety of scales in sketches and writing, are better. Students can also better distinguish between observation and inference in report writing. Finally, students can apply their theoretical understanding of petrologic processes (e.g. magma differentiation, metamorphic facies progressions) to real rocks in a more sophisticated way using evidence.

DeBari, S. M.

2011-12-01

128

Petrology, chemistry, and origin of Apollo 15 regolith breccias  

NASA Astrophysics Data System (ADS)

Variations in modal petrology, mineral compositions, and bulk compositions were determined for ten Apollo 15 regolith breccias for comparison with local soils and assessment of the intrasite petrologic variability of the Apollo 15 regolith. Based on the above criteria the breccias are of local origin and mimic the soils from the corresponding sampling stations, with the exception of station 2 breccia 15205. This sample formed from an anomalous regolith, and although not considered exotic to the site is not representative of the soil at the site. KREEP basalt and green glass components vary from trace amounts to dominant in the breccias, evidence that these materials entered the regolith prior to formation of the breccias. Breccias from the edge of Hadley Rille are modally richer in highland fragments than the soils, whereas at the base of Hadley Delta the reverse is true. This is explained by the loss of material into the Rille to be replaced by basalt-derived material, making the soils more basalt-rich. At the base of Hadley Delta highland material is accumulating and the soils are becoming more highland-rich. Over billions of years these processes have developed differences between the present day, evolving soils, and 'fossil' nonevolving soils represented by the regolith breccias. This shows that there has been little change in the geology and the morphology of the Apollo 15 site, probably since the eruption of mare basalts at the site (about 3.3 b.y.).

Simon, S. B.; Papike, J. J.; Gosselin, D. C.; Laul, J. C.

1986-12-01

129

Virtual Observatories  

NASA Astrophysics Data System (ADS)

Astronomy has been at the forefront among scientific disciplines for the sharing of data, and the advent of the World Wide Web has produced a revolution in the way astronomers do science. The recent development of the concept of Virtual Observatory builds on these foundations. This is one of the truly global endeavours of astronomy, aiming at providing astronomers with seamless access to data and tools, including theoretical data. Astronomy on-line resources provide a rare example of a world-wide, discipline-wide knowledge infrastructure, based on internationally agreed interoperability standards.

Genova, Françoise

2011-06-01

130

Virtual endoscope  

NASA Astrophysics Data System (ADS)

This paper reports on the initial developmental stages of an endoscope that can be used for medical and other applications requiring 3-D images. The conceptual basis for the design is derived from our prior efforts in the development of 3-D scopes for laparoscopy and from telepresence research with head-mounted displays for use in virtual reality. We include the initial results of the development of the viewing system and the design for the scope. Specific future research efforts and developmental phase also are described.

McLaurin, A. P.; Jones, Edwin R.

1994-04-01

131

Virtual asteroids and virtual impactors  

NASA Astrophysics Data System (ADS)

When a celestial body, e.g., an asteroid, has been observed only over a short time, its orbit is not well determined but may be anywhere in a confidence region where the astrometric residuals are acceptable. This region can be sampled by a swarm of Virtual Asteroids (VA) sharing the reality of the asteroid: one of them is real, but we do not know which one. The problem is how to sample the confidence region with a small number of VA, still being able to solve the main problems of asteroid recovery/identification and impact monitoring.

Milani, Andrea

2005-02-01

132

The Scanning Electron Microscope.  

National Technical Information Service (NTIS)

The scanning electron microscope combines the techniques of the cathode-ray tube and the conventional electron microscope--both considered indispensable to modern technology. The SEM, which presents a picture having a distinct three-dimensional appearance...

R. F. W. Pease

1968-01-01

133

Petrology, Mineralogy and Mineral Chemistry of Antarctic Monomict Eucrites CMS 04049 and QUE 97053  

NASA Astrophysics Data System (ADS)

We report petrology and mineral chemistry data including trace element abundances in minerals of two monomict eucrites, CMS 04049 and QUE 97053 to understand igneous and post-crystallization history of eucrite.

Righter, M.; Lapen, T. J.

2010-03-01

134

Cathodoluminescence Color Indices as a Parameter for Measuring Petrologic Changes in Meteorites  

NASA Astrophysics Data System (ADS)

Cathodoluminescence (CL) is the emission of light during exposure to an electron beam. Here, we discuss using the CL properties of meteorites to determine their petrologic type, with emphasis on CM, CO, ordinary and enstatite chondrites, and achondrites.

Meier, A.; Akridge, D. G.; Akridge, J. M. C.; Batchelor, J. D.; Benoit, P. H.; Brewer, J.; Dehart, J. M.; Keck, B. D.; Lu, J.; Schneider, D. M.; Sears, D. W. G.; Symes, S. J. K.; Zhang, Y.

2003-03-01

135

Petrological and Mineralogical Study of Compact Type A CAI in the Allende CV Chondrite  

NASA Astrophysics Data System (ADS)

We have examined the petrological and mineralogical characteristics of a compact type A (CTA) CAI in the Allende CV chondrite using SEM and TEM in order to shed light on the details of crystallization process of CTA.

Ohnishi, I.; Suzuki, T.; Yoshitake, M.; Yamashita, K.

2013-09-01

136

Petrology, Mineralogy, and Noble Gas Composition of the Dubrovnik L Chondrite Breccia  

NASA Astrophysics Data System (ADS)

Petrology, mineralogy, and noble gas composition of the Dubrovnik L chondrite breccia showing beautiful dark-light structure are characterized. It consists mainly of L6 material with minor amounts of less equilibrated material and experienced little heati

Yokoyama, T.; Nakamura, T.; Okazaki, R.; Saiki, K.

2007-03-01

137

Linking Petrology and Seismology at an Active Volcano  

NASA Astrophysics Data System (ADS)

Many active volcanoes exhibit changes in seismicity, ground deformation, and gas emissions, which in some instances arise from magma movement in the crust before eruption. An enduring challenge in volcano monitoring is interpreting signs of unrest in terms of the causal subterranean magmatic processes. We examined over 300 zoned orthopyroxene crystals from the 1980-1986 eruption of Mount St. Helens that record pulsatory intrusions of new magma and volatiles into an existing larger reservoir before the eruption occurred. Diffusion chronometry applied to orthopyroxene crystal rims shows that episodes of magma intrusion correlate temporally with recorded seismicity, providing evidence that some seismic events are related to magma intrusion. These time scales are commensurate with monitoring signals at restless volcanoes, thus improving our ability to forecast volcanic eruptions by using petrology.

Saunders, Kate; Blundy, Jon; Dohmen, Ralf; Cashman, Kathy

2012-05-01

138

Virtual Sweden  

NSDL National Science Digital Library

Panoramic photographs that immerse their audience in a landscape have been in vogue throughout the history of photographic enterprises. With this in mind, users should not be surprised to learn of the existence of the Virtual Sweden website. Established by Jonas Carlson in 2003, the site contains 360 degree panoramic images taken by Carlson from a wide variety of locales across the globe. Of course, visitors should start by looking at the panoramic photograph taken from the Gronskar lighthouse in the Stockholm archipelago, but then they would be remiss not to look at some of the other available images. Some of the other places Carlson has seen fit to document are Rome, Thailand, Egypt, and London. Visitors can peruse a thematic list of these locations, or they may simply go straight to his "Latest additions" list, which is also on the site's homepage.

Carlson, Jonas

2005-01-01

139

Virtual models  

US Patent & Trademark Office Database

A method of generating a virtual model of an object, comprising the step of constructing a fused model to represent the variation of the shape of the object in a plurality of configurations. In the method, position variation vectors may be calculated which describe the variation of a plurality of points in the fused model from their mean positions over all the configurations of the object; the position variation vectors may be assigned a weighting factor which represents a measure of their probabilistic confidence; a weighted covariance matrix may be constructed to represent the variations; the weighted covariance matrix may be operated on to obtain shape variation vectors representing the weighted direction and magnitude of variations; such that the fused model may describe how the shape of the object varies as a function of the shape variation vectors scaled by a shape parameter.

Fisher, III; Robert Burns (Scotland, GB); Faber; Petko (Leonberg, DE); Lukins; Timothy Campbell (Scotland, GB)

2008-10-21

140

Virtual Norfolk  

NSDL National Science Digital Library

An experiment in teaching with historical texts still in the early stages of development, Virtual Norfolk (Norfolk County, UK) offers five content modules that include seminars, topics, and illustrative documents. For example, the Social History of Early Modern England module includes the Everyday Lives seminar, which has among its topics Crime and the Law, where one can read the digitized version of "prosecution of Benet Goodwyn for whoring" from Norwich City Records, City Quarter Sessions, Book of Examinations and Depositions, 1561-67. Some introductory sections and commentaries have yet to be written by project staff, scholars from the University of East Anglia, and the glossary "will appear here shortly." Although parts of the site are still under construction, all historical texts are searchable by keyword; so, it is quite easy for users to broaden a search after looking over a few documents and discovering terms of interest.

2001-01-01

141

Virtual Laboratory  

NSDL National Science Digital Library

The website for the Virtual Laboratory contains a bold and direct statement: "Conventional teaching all too often accepts memorization and pattern recognition as true learning" After reading this statement, it makes sense that the goal of this site is "to help students to recognize, confront, correct, and expand their understanding of subject or a technique." The site contains five different sets of course materials that use interactive materials, short quizzes, and embedded demonstrations to assist students and teachers alike. One set of materials that should not be missed is in the Teaching & Learning Biology area. Here visitors will find links, fact sheets, and pedagogical suggestions for teaching a college-level biology course. Moving on, the Chemistry, Life, the Universe and Everything section contains a new perspective on how to reform the garden-variety general chemistry course.

2012-04-27

142

Optical versus virtual: teaching assistant perceptions of the use of virtual microscopy in an undergraduate human anatomy course.  

PubMed

Many studies that evaluate the introduction of technology in the classroom focus on student performance and student evaluations. This study focuses on instructor evaluation of the introduction of virtual microscopy into an undergraduate anatomy class. Semi-structured interviews were conducted with graduate teaching assistants (TA) and analyzed through qualitative methods. This analysis showed that the teaching assistants found the virtual microscope to be an advantageous change in the classroom. They cite the ease of use of the virtual microscope, access to histology outside of designated laboratory time, and increasing student collaboration in class as the primary advantages. The teaching assistants also discuss principal areas where the use of the virtual microscope can be improved from a pedagogical standpoint, including requiring students to spend more time working on histology in class. PMID:22069298

Collier, Larissa; Dunham, Stacey; Braun, Mark W; O'Loughlin, Valerie Dean

2011-11-08

143

An Inquiry-Based Approach to Learning Petrology Using Student-Generated Data  

NSDL National Science Digital Library

The Petrology course at Macalester College is designed around a semester-long project. All laboratory and classroom activities within the course are directed toward understanding and solving a real-world problem, the origin and evolution of an intrusion in northern Minnesota. Emphasis is on using multi-disciplinary approaches, modern instrumentation, and student-generated data. After completing the course, students exhibit improved quantitative skills, reasoning, and understanding of fundamental petrologic processes.

Wirth, Karl R.

144

Petrology and mineralogy of the Ningqiang carbonaceous chondrite  

NASA Astrophysics Data System (ADS)

We report detailed chemical, petrological, and mineralogical studies on the Ningqiang carbonaceous chondrite. Ningqiang is a unique ungrouped type 3 carbonaceous chondrite. Its bulk composition is similar to that of CV and CK chondrites, but refractory lithophile elements (1.01 × CI) are distinctly depleted relative to CV (1.29 × CI) and CK (1.20 × CI) chondrites. Ningqiang consists of 47.5 vol% chondrules, 2.0 vol% Ca,Al-rich inclusions (CAIs), 4.5 vol% amoeboid olivine aggregates (AOAs), and 46.0 vol% matrix. Most chondrules (95%) in Ningqiang are Mgrich. The abundances of Fe-rich and Al-rich chondrules are very low. Al-rich chondrules (ARCs) in Ningqiang are composed mainly of olivine, plagioclase, spinel, and pyroxenes. In ARCs, spinel and plagioclase are enriched in moderately volatile elements (Cr, Mn, and Na), and low-Ca pyroxenes are enriched in refractory elements (Al and Ti). The petrology and mineralogy of ARCs in Ningqiang indicate that they were formed from hybrid precursors of ferromagnesian chondrules mixed with refractory materials during chondrule formation processes. We found 294 CAIs (55.0% type A, 39.5% spinel-pyroxene-rich, 4.4% hibonite-rich, and several type C and anorthite-spinelrich inclusions) and 73 AOAs in 15 Ningqiang sections (equivalent to 20 cm2 surface area). This is the first report of hibonite-rich inclusions in Ningqiang. They are texturally similar to those in CM, CH, and CB chondrites, and exhibit three textural forms: aggregates of euhedral hibonite single crystals, fine-grained aggregates of subhedral hibonite with minor spinel, and hibonite ± Al,Ti-diopside ± spinel spherules. Evidence of secondary alteration is ubiquitous in Ningqiang. Opaque assemblages, formed by secondary alteration of pre-existing alloys on the parent body, are widespread in chondrules and matrix. On the other hand, nepheline and sodalite, existing in all chondritic components, formed by alkali-halogen metasomatism in the solar nebula.

Wang, Y.; Hsu, W.

2009-07-01

145

Computed tomographic microscope: theory of microscopic CT  

NASA Astrophysics Data System (ADS)

Getting information of microstructure of living body with non-invasive method is a subject that scientists have long been exploring. Up to now, CT system such as X-ray computed tomography (X-CT), emission computed tomography (ECT or (gamma) -CT) and nuclear magnetic resonance computed tomography (NMR-CT), etc., can only resolve macrostructure no smaller than 1 millimeter except ultrasonic microscope (USM). By way of a long duration of studying and the simulating test, the authors of this paper proposed a theory of the computed tomographic microscope with living body (CTM), or microscopic CT(MCT), and invented a new technology: X-ray transmission electron microscope (XEM or IIMT), which has been granted patent by the Patent Office of P.R.C.

Chen, Wenbin; Yian, Yian; Zhang, Qiju; Li, Tongpi; Guo, Tiechen; Liu, Zhong; Qin, Huiji; Li, Daoqin

1994-08-01

146

Internet-enabled high-resolution brain mapping and virtual microscopy  

Microsoft Academic Search

Virtual microscopy involves the conversion of histological sections mounted on glass microscope slides to high-resolution digital images. Virtual microscopy offers several advantages over traditional microscopy, including remote viewing and data sharing, annotation, and various forms of data mining.We describe a method utilizing virtual microscopy for generation of internet-enabled, high-resolution brain maps and atlases. Virtual microscopy-based digital brain atlases have resolutions

Shawn Mikula; Issac Trotts; James M. Stone; Edward G. Jones

2007-01-01

147

Virtual electron microscopy in cell biology.  

PubMed

Virtual microscopy of histological glass slides can emulate conventional light microscopy. Up till now, such a digital simulation does not exist for ultrathin electron microscopic slides. Because of the relative inaccessibility of electron microscopy, evaluation of subcellular structures by (bio)medical students is performed with the aid of photographic prints. In this article, the generation and evaluation of virtual electron microscopic slides is discussed. A T-lymphoblastic cell was used as an example. Electron microscopic pictures were taken at two magnifications (25,000 and 50,000), processed in an analogue or digital way and stitched to reconstruct the image of the total cell. This image is viewed with a webviewer equipped with pan and zoom functions. The possibility of distinguishing the trilaminar structure of cellular membranes was the requisite. Virtual images obtained at an original magnification of 25,000, scanned at a resolution of 800 ppi could compete with pictures developed directly from negatives obtained by electron microscopy. It is possible to navigate and zoom into details in a way emulating electron microscopy. Virtual electron microscopy is innovative and offers new perspectives to interpret cytological pictures and to teach cell biology in an interactive and unique way. Microsc. Res. Tech., 2010. © 2010 Wiley-Liss, Inc. PMID:20623756

Mione, Sylvia; Bacher, Klaus; Thierens, Hubert; Cornelissen, Maria

2011-03-01

148

Virtual Titanic  

NSDL National Science Digital Library

The recent historical and cinematic fascination with the Titanic proves that the allure of this most famous luxury liner remains unsinkable. The Discovery Channel Online has created a captivating site devoted to images, movies (IPIX, QuickTime), and text describing the ship and its demise. While the site contains historical photos and lithographs of the ship as well as underwater photos and movies from a 1985 submersible mission, the unique contribution of this site is its numerous virtual images of the interior and exterior of the Titanic as well as its movies of the collision and sinking. Developed by Andrew Nelson for a CD-ROM game, the movies include a flyby of the ship, a collision movie, a listing movie, and a three-part series of the sinking. Both flat and "bubble" views of such features as the first-class cabins, the wireless room, and the grand staircase are also included. A talk-back section discusses various theories surrounding the sinking and contains several related links.

1997-01-01

149

Virtual histology  

PubMed Central

As a luminogram, coronary angiography provides a good overview of the coronary artery tree. Using quantitative coronary measurements, the degree of coronary obstruction can be determined. The limitation of coronary angiography is that it does not provide information on the arterial wall structure and therefore cannot assess the extent of atherosclerosis. Knowledge about adaptive coronary remodelling processes as compensatory enlargement of the coronary artery has focused diagnostic interest on the non?stenotic lesions of the coronary tree. Intravascular ultrasound (IVUS) can reveal discrepancies between the extent of coronary atherosclerosis and angiography imaging by in vivo plaque imaging. Spectrum analysis of IVUS?derived radiofrequency (RF) data enables a more detailed analysis of plaque composition and morphology. Preliminary in vitro studies correlated four histological plaque components with a specific spectrum analysis of the RF data. The different components (fibrous, fibrofatty, necrotic core and dense calcium) are colour coded. Coronary tissue maps were reconstructed from RF data using IVUS–Virtual Histology (VH IVUS) software (Real?Time VH, Volcano Corporation, Rancho Cordova, California, USA). VH IVUS has the potential to detect high?risk lesions and can provide new insights into the pathophysiology of coronary artery disease. VH IVUS allows the differentiation of different lesion types based on information derived from histopathology. The in vivo specific histological analysis of coronary atherosclerosis may allow better stratification of treatment of patients with coronary artery disease.

Konig, Andreas; Klauss, Volker

2007-01-01

150

Virtual Schemas and Bases  

Microsoft Academic Search

We propose the notions of virtual schemas and virtual bases as a coherent way ofintegrating various features in OODB views. A virtual schema is defined based on someexisting (real) schema. A virtual base is obtained when a (real) base is attached to avirtual schema. We study the consequences of this simple assumption. In particular,we observe the differences between a real

Cassio Souza Dos Santos; Serge Abiteboul; Claude Delobel

1994-01-01

151

Isotopic Petrology: The Curious Case of the Shergottite Meteorites  

NASA Astrophysics Data System (ADS)

The shergottites comprise a diverse suite of martian basalts and basaltic cumulates. As of 1985, there were three proposed igneous ages for this group of basaltic rocks: (i) 4-4.5 b.y. [1; Caltech]; (ii) 1.3 b.y. [2; JSC]; and (iii) 360 m.y. [3; Mainz]. At that time I proffered that petrographic observations demanded that the shergottites were only 180 m.y. old [4]. By 1985, all the above geochronology groups had presented evidence of a young 200 m.y. age, but interpreted that as a metamorphic resetting. My observation was considered extremely controversial. However, John Longhi was instrumental, perhaps pivotal, in causing this new, controversial interpretation to be accepted, at least among petrologists. John then used this newfound knowledge to infer the Nd isotopic composition of the martian crust [5]. This new interpretation of shergottite chronology has led to petrologic insights that would not otherwise have been possible: (I) There were melt extraction events in the shergottite mantle immediately(?) preceding shergottite formation; and (II) the variation in enriched vs. depleted characteristics of the shergottites is best explained by assimilation of ancient, enriched crust by young magmas from a depleted source region. I. Internal, mineral isochrons of the shergottites (15 years later) vary from 165 m.y. to 575 m.y. [6]. Without exception, the Sm/Nd ratios of the shergottites themselves are larger than the time-integrated Sm/Nd ratio of their source regions [7]. This means that there has been a LREE-enriched phase that has fractionated from the shergottites. There are no solid phases in the martian mantle that are capable of this. This implies that LREE-enriched magmas escaped the shergottite source regions just prior to shergottite petrogenesis. II. Therefore, the shergottites can be characterized in terms of three Sm-Nd components: (i) a primitive shergottite magma from a depleted source region; (ii) an enriched crust; and (iii) a missing LREE-enriched melt. Interestingly, the 180 m.y. shergottites require only two Sm-Nd components, because they fall along a two-component mixing line. This implies that these shergottites were derived from a single magma, that was generated from a single, LREE-melt-extracted source region, which subsequently assimilated various amounts of enriched crust. Otherwise, the amount of assimilated crust for each shergottite would be required to be linked to the amount of missing, LREE-enriched magma, in such a way that a two-component linear array is generated. Since LREE melt extraction had to occur before depleted-shergottite petrogenesis and since crustal assimilation must have occurred after, these two physical processes have little chance of being coupled. In addition, this linear shergottite mixing array must be of sufficient quality that it could initially be interpreted as an isochron [2]. This interpretation of 180 m.y. shergottite petrogenesis reinforces Longhi's inference of the Nd isotopic composition of the martian crust [5], at least in one particular martian terrain. Bottom line: In order to understand martian chronology, you have to understand martian petrology. And in order to understand martian petrology, you have to understand martian chronology. This is an aphorism that (I think) John would endorse. [1] Chen and Wassserburg (1986) Geochim. Cosmochim. Acta 50, 955-968. [2] Shih et al. (1982 Geochim. Cosmochim. Acta 46, 2323-2344. [3] Jagoutz and Wanke (1986) Geochim. Cosmochim. Acta 50, 939-953. [4] Jones (1986) Geochim. Cosmochim. Acta 50, 969-977. [5] Longhi (1991) Proc. Lunar Planet. Sci. Conf. 21st, 695-709. [6] Nyquist et al. (2001) In Chronology and Evolution of Mars 96, pp. 105-164. [7] Borg (2003) Geochim. Cosmochim. Acta 67, 3519-3536.

Jones, J. H.

2009-05-01

152

Recurrence tracking microscope  

SciTech Connect

In order to probe nanostructures on a surface we present a microscope based on the quantum recurrence phenomena. A cloud of atoms bounces off an atomic mirror connected to a cantilever and exhibits quantum recurrences. The times at which the recurrences occur depend on the initial height of the bouncing atoms above the atomic mirror, and vary following the structures on the surface under investigation. The microscope has inherent advantages over existing techniques of scanning tunneling microscope and atomic force microscope. Presently available experimental technology makes it possible to develop the device in the laboratory.

Saif, Farhan [Department of Electronics, Quaid-i-Azam University, Islamabad 45320, Pakistan and Department of Physics, University of Arizona, Tucson, Arizona 85721 (United States)

2006-03-15

153

A microscopic approach to nuclear reactions: General formalism  

Microsoft Academic Search

In this first of two successive papers we present a microscopic model for nuclear reactions. It allows the description of elastic and inelastic nucleon scattering as well as photonuclear reactions with real and virtual photons. The model is based on a particular classification scheme of the many-body Hilbert space according to the number of continuum nucleons. By its very definition

B. Fladt; K. W. Schmid; F. Gruemmer

1988-01-01

154

Developing Virtual Storytellers for the Virtual Alhambra  

Microsoft Academic Search

Thanks to the technological advances in the last ten years, the recreation of 3D virtual worlds is becoming increasingly popular\\u000a in several application fields. Desktop virtual reality is one of the best ways of reaching a good number of users through\\u000a this technology. With the aim of improving the development of desktop virtual reality applications and increasing the relevance\\u000a of

José L. Fuertes; Ángel Lucas González; Gonzalo Mariscal; Carlos Ruiz

2007-01-01

155

Photography through the Microscope.  

ERIC Educational Resources Information Center

|Describes how to illuminate and optically stain slides for microscope use and how to interface a 35mm camera with a microscope using an adaptor. Provides equipment descriptions and sources, details about illumination, image formation, darkfield adaptors, centerable filter adaptors, darkfield stops, rheinburg filters, and choosing specimens to…

McNeil, D. W.

1992-01-01

156

Complete and rapid switch from light microscopy to virtual microscopy for teaching medical histology.  

PubMed

During the interim between the 2003 and 2004 academic years, the cell and tissue biology and integrated medical neuroscience courses at the Medical College of Wisconsin made a complete and rapid switch from light microscopy- to virtual microscopy-based histology laboratories. This switch was prompted by the difficulties in maintaining and the cost of replacing the college's microscopes and microscope slides, and primarily by the desire to promote and streamline learning for our large classes (n > 200) of first-year medical students. A group of students who used the virtual microscope, another group of students who used the light microscope, and faculty with experience using both tools rated the effectiveness of the virtual microscope for learning and teaching. Also, to determine whether virtual microscopy affected student learning, laboratory examination scores for the 2004 class (n = 209) were compared with those of four previous classes that used light microscopes exclusively (n = 811). The switch from light microscopy to virtual microscopy was very favorably received by both students and faculty. More importantly, data from examination scores and course evaluation surveys indicated that use of the virtual microscope may significantly improve student performance and learning efficiency. Procedures for successfully implementing this change are described. PMID:16032757

Krippendorf, Beth B; Lough, John

2005-07-01

157

Parallax: virtual disks for virtual machines  

Microsoft Academic Search

Parallax is a distributed storage system that uses virtualization to provide storage facilities specifically for virtual enviro nments. The system employs a novel architecture in which storage features that have traditionally been implemented directly on high-end storage arrays and switches are relocated into a federation of storage VMs, sharing the same physical hosts as the VMs that they serve. This

Dutch T. Meyer; Gitika Aggarwal; Brendan Cully; Geoffrey Lefebvre; Michael J. Feeley; Norman C. Hutchinson; Andrew Warfield

2008-01-01

158

Digital atomic force microscope moiré method.  

PubMed

In this study, a novel digital atomic force microscope (AFM) moiré method is established to measure the displacement and strain fields. The moiré pattern is generated by the interference between the specimen grating and the virtual reference grating formed by digital image processes. The overlapped image is filtered by the 2-D wavelet transformation to obtain clear interference moiré patterns. From moiré patterns, the displacement and strain fields can be analyzed. The experimental results show that the digital AFM moiré method is very sensitive and easy to realize in nanoscale measurements. PMID:15450663

Liu, Chia-Ming; Chen, Lien-Wen

2004-11-01

159

HHMI: Virtual Neurophysiology Lab  

NSDL National Science Digital Library

This Virtual Lab provides students the opportunity to explore the electrical activity of individual neurons by virtually stimulating the skin of a leech. A lab notebook, equipment list, atlas of cells and recordings is provided to simulate a lab activity.

HHMI (Howard Hughes Medical Institute)

2012-12-01

160

Virtual Reality as Metaphor.  

ERIC Educational Resources Information Center

|Suggests that virtual reality technology has become popular because it is a miniaturization, a model, of something that already exists. Compares virtual reality to the news media, which centers on the gory, the sensational, and the distorted. (PA)|

Gozzi, Raymond, Jr.

1996-01-01

161

Virtual Library Design Document.  

National Technical Information Service (NTIS)

The objective of this document is to establish a design for the virtual library user and administrative layers that complies with the requirements of the virtual library software specification and subordinate module specification.

M. A. de Lamare

2001-01-01

162

Immersion interferometer for microscopic moire interferometry  

NASA Astrophysics Data System (ADS)

The basic sensitivity of moire interferometry has been increased beyond the previously conceived theoretical limit. This is accomplished by creating the virtual reference grating inside a refractive medium instead of air, thus shortening the wavelength of light. Various optical configurations of moire interferometry for operation in a refractive medium are introduced and one of them has been put into current practice. A very compact four-beam immersion interferometer has been developed for microscopic viewing, which produces a basic sensitivity of 4.8 fringes per micron displacement (contour interval of 0.208 micron per fringe order), corresponding to moire with 4800 lines per mm. Its configuration makes it inherently stable and relatively insensitive to environmental disturbances. An optical microscope is employed to obtain high spatial resolution. The method is demonstrated for deformation of a thick graphite/epoxy composite at the 0/90-deg ply interface.

Han, B.; Post, D.

1992-03-01

163

The virtual space exploration education portal  

NASA Astrophysics Data System (ADS)

New information technologies have evolved from space exploration—3-D visualisation ‘lenses’ and a growing suite of tools that allow access to exploration, analysis and interpretation of often complex information by a range of end users including the public, communicators, and policy makers. These tools have only become viable in the past year or two with the combination of the availability of inexpensive, but powerful, personal computers and widespread use of the Internet. A new study group under Commission 6 has been established, entitled ‘Future Directions of Space Exploration Education’, to build a Virtual Global Space Exploration Education Portal (VGSEEP) to open this revolution to all audiences, not just students. This paper describes the initial stages of VGSEEP. The NASA Learning Technologies suite of ‘lenses’ and tools will be demonstrated: World Wind, a 3-D globe that provides insights into our planet from space and almost down to ground level; the Virtual Field Trip that explores at ground level in 3-D; the Virtual Lab, which allows a range of samples to be examined via a virtual light microscope and/or a Scanning Electron Microscope and What’s the Difference?, which allows users to manipulate information in a multi-graphical interface.

Oliver, C. A.

2007-06-01

164

Petrologic Insights into Magma System Response to Edifice Collapse  

NASA Astrophysics Data System (ADS)

In order to understand eruptive behavior at volcanic centers and to improve models for monitoring and prediction of volcanic eruptions, it is important to constrain magma storage conditions and transport in the system. Here the post-collapse eruptive behavior at Bezymianny and Shiveluch volcanoes, (Kamchatka Peninsula, Russia) are each compared to the well-known sequence at Mount St. Helens, Washington, USA (from 1956, 1964, and 1980, respectively). The magma system responds to rapid unloading of overburden pressure, due to edifice collapse, with a violent large-scale paroxysmal eruption. This reflects the amplitude of the triggering decompression event with later dome-building and explosive activity due to the reduction of vent elevation. The massive unloading events and post-collapse eruptive chronologies, provides a unique opportunity for comparison of the sources driving the catastrophic eruptions and eruptive style transitions. Analytical techniques employed included X-ray fluorescence spectroscopy, electron probe micro-analyses, Fe-Ti oxide and two-pyroxene geothermometry, X-ray elemental mapping, and a novel image processing technique. Presented here are results from petrological investigations into the temporal variations of whole-rock geochemistry, geothermometry, mineral modal abundances and textures. Bezymianny is becoming more mafic over time from 61.0 to 57.3 wt.% SiO2 (1956 and 2010). Pre-eruptive magma temperatures increased from 950oC to 1050oC from 1956 to 2006. Plagioclase and amphibole disequilibrium textures are observed throughout the time series and rare mafic enclaves exist. The whole-rock chemical trend at Shiveluch shows a subtle, yet reversed trend from 60.6 to 64.2 wt.% SiO2 (1964 and 2007). Two-pyroxene geothermometry yields ~950oC+30oC (2001-2007) and is consistent with data from the 2001 -2004 eruption, of 834-978oC+60oC. Mafic enclaves occurred throughout the entire period of eruptive activity at Shiveluch. In contrast to both Bezymianny and Shiveluch, the Mount St. Helens erupted a compositionally uniform crystal-rich dacite, 65 wt.% SiO2 in 2004. Magmatic temperatures from 1980-1981 ~930oC and in 2004-2006 they had decreased to ~850oC. At this stage, a continuous and possibly punctuated replenishment of mafic magma from depth appears to be driving the frequency of eruptions and observed transitions in eruptive style at Bezymianny. At Shiveluch, an increasingly silicic geochemical trend, high temperatures and the presence of mafic enclaves, may indicate a re-mobilization of host dacite by basalt ponded at the base of the deep seated magma reservoir. Models of magma replenishment and mixing at Bezymianny and Shiveluch are discussed in the context of magma system response to edifice collapse and compared to Mount St. Helens. It is demonstrated here, that petrologic studies serve to elucidate short-time scale behavior of these magmatic systems and to enable projections of future volcanic activity.

Shipman, J. S.; Izbekov, P. E.; Gavrilenko, M.

2011-12-01

165

Petrology of the Upper Border Series of the Skaergaard Intrusion  

NASA Astrophysics Data System (ADS)

The Upper Border Series crystallized downwards from the roof of the Skaergaard magma chamber. It met with the Layered Series that crystallized upwards from the floor in the Sandwich Horizon that contains the last and most evolved rocks of the intrusion. Previous investigations of the Upper Border Series (Naslund, 1984) have shown that the compositional trends of plagioclase, olivine and pyroxene largely mirror those of the Layered Series. At the same time it was argued that the crystallization sequence in Upper Border Series differed from the Layered Series in that apatite precipitated before magnetite that, in turn, appeared before Ca-rich pyroxene. From the existing data the magma from which the Upper Border Series crystallized was inferred to be enriched in SiO2, K2O, P2O5 and H2O relative to the magma in the lower parts of the intrusion. This has lead to the conception that the Upper Border Series crystallized from a chemically different magma. Here we present new petrography, mineralogy and bulk compositions for samples collected in three profiles through the Upper Border Series (Kilen, Hammerpas and Brødretoppen transects). Although euhedral apatite is present throughout most of the Upper Border Series, we interpret a marked increase in modal apatite late in the crystallization sequence as marking its first appearance on the liquidus at the crystallization front. The plagioclase An% at this level in the Upper Border Series is ˜40 and is identical with plagioclase An% at the level of apatite-in in the Layered Series. Similarly, we find that the plagioclase An% at the onset of FeTi-oxide and sulphide precipitation in the Upper Border Series (52 and 47, respectively) and Layered Series are alike. Finally, we interpret abundant augite in Upper Border Series rocks before magnetite-in as a cumulus phase. We therefore conclude that the crystallization sequences of the two series are identical. The new bulk rock data reveal that the Upper Border Series and the Layered Series are similar in the early stages of differentiation until after FeTi-oxides appear as primocrysts. In the more evolved rocks the Upper Border Series is gradually enriched in SiO2, K2O and incompatible trace elements relative to the Layered Series as shown by Naslund (1984). This is expressed by abundant interstitial granophyre pockets between the cumulus crystals in the Upper Border Series. However, we find that it is possible to explain the Upper Border Series as a mixture of cumulus minerals and reasonable liquid estimates. Thus the Upper Border Series appears to trap a higher fraction of residual liquid than is the case in the Layered Series. We conclude that the Upper Border Series crystallized from the same liquid as the Layered Series and mainly differs in a high amount of trapped liquid. This implies that the Skaergaard chamber had only one convecting magma body. References: Naslund, H.R.; Petrology of the Upper Border Series of the Skaergaard Intrusion, Journal of Petrology, Vol. 25, Part 1, pp 185-212, 1984

Salmonsen, L.; Tegner, C.; Jakobsen, J. K.

2009-12-01

166

Biquandles for Virtual Knots  

Microsoft Academic Search

This paper studies an algebraic invariant of virtual knots called the biquandle. The biquandle generalizes the fundamental group and the quandle of virtual knots. The approach taken in this paper to the biquandle emphasizes understanding its structure in terms of compositions of morphisms, where elementary morphisms are associated to oriented classical and virtual crossings in the diagram.

David Hrencecin; Louis H. Kauffman

2007-01-01

167

Leadership in Virtual Teams  

Microsoft Academic Search

Today's organizations use virtual teams in order to respond to their dynamic environ- ments. Members in virtual teams geographically dispersed and coordinate their work predomi- nately via information and communication technology (ICT). Leadership in virtual teams need to redefined, it is surely different from the traditional one. In this paper we try to answer this question: How does ICT affect

Amin Kaboli; Mojtaba Tabari; Elham Kaboli

168

Virtual Clone Fish Experiment  

Microsoft Academic Search

A virtual clone fish experimental system is designed and set up. The system simulates the clone fish experiment process using the technique of virtual reality based on behavior model. Through the experiment, users can further observe the results and make conclusion more conveniently and quickly. The virtual clone fish experiment can reduce unnecessary waste caused in a reality clone fish

Qian Xu; Wen-Yong Wang; Shao-Chun Zhong; Xiao-lin Quan; Qingrong Zhang; Ying Liang

2006-01-01

169

The Beagle 2 Microscope  

NASA Astrophysics Data System (ADS)

The Beagle 2 microscope provides optical images of the Martian surface at a resolution 5x higher than any other experiment currently planned. By using a novel illumination system it images in three colors and can also detect fluorescent materials.

Lüthi, B. S.; Thomas, N.; Hviid, S. F.; Keller, H. U.; Markiewicz, W. J.; Blümchen, T.; Smith, P. H.; Tanner, R.; Oquest, C.; Reynolds, R.; Josset, J.-L.; Beauvivre, S.; Hofmann, B.; Rüffer, P.; Pillinger, C. T.

2004-03-01

170

Scanning Electron Microscope.  

National Technical Information Service (NTIS)

The electron microscope utilizes only a single lens system. The system includes a point source of monoenergetic electrons with an arrangement for focusing the electrons into a spot on a specimen, a raster type scanner, a momentum analyzer, a scintillation...

A. V. Crewe

1965-01-01

171

Petrology and Geochemistry of Acapulco- and Lodran-like Achondrites  

NASA Astrophysics Data System (ADS)

Primitive achondrites are meteorites that have mineral and bulk compositions similar to chondrites, but have non-chondritic textures. These achondrites were metamorphosed at high temperatures, perhaps up to that of the Fe-FeS eutectic or chondrite silicate solidus [1]. We have initiated geochemical and petrologic study of several Acapulco- and Lodran-like achondrites in order to test petrogenetic models based largely on petrologic arguments. We have studied the following meteorites: ALHA81187 and ALHA81261 (Acapulco-like), LEW88280 and MAC88177 (Lodran-like) and EET84302 (transitional) [1]. Of our Acapulco-like achondrites, we have finished petrologic characterization only on ALHA81187. Our thin section is distinct from that studied by [1] in that orthopyroxene is the dominant silicate, and we found no plagioclase. The low plagioclase content is like that of Lodran-like achondrites, but our INM data (below) suggest that the thin section is unrepresentative. LEW88280 and MAC88177 are medium-grained, granular rocks with metal and troilite occurring as inclusions in silicates, as thin veins cutting silicates and as discrete grains of intergrown kamacite and troilite. Our thin section of EET84302 is metal, sulfide, and chromite. Clinopyroxene and plagioclase occur in minor amounts. Orthopyroxene grains contain abundant metal inclusions in linear trains. The texture is similar to cumulate sulfide textures found in some terrestrial igneous rocks. Acapulco-like achondrites have been suggested to be high grade metamorphic rocks in which partial melting of Fe-FeS and phosphates occurred [2], although the melts may not have left the parent rock. Our and literature [3-6] INAA data generally agree with this interpretation: Sm/Sc ratios of Acapulco-like achondrites are between 0.8-2 times H chondrites, and Na/Sc ratios are between ~0.7-1.2 times H chondrites indicating that neither silicate nor "phosphate" partial melts were lost from the rocks. Siderophile and chalcophile elements are fractionated. Y-74063 has high Se/Co and low Ir/Ni ratios [6], while ALHA81187 has low Se/Co and high Ir/Ni ratios. This variation is consistent with either fractionation by partial melting in the Fe-Ni-S system, or with heterogeneous distribution of metal and troilite in these achondrites. This can be tested through additional analyses of the meteorites. If the samples of Y-74063 and ALHA81187 are representative of these achondrites, then the results suggest that mobilization of Fe-FeS eutectic melts occurred. The Lodran-like achondrites are believed to be partial melting residues [7]. The trace lithophile element data on Lodran [8], LEW88280, and MAC 88177 are compatible with this interpretation. Highly incompatible elements are depleted relative to more compatible elements such as Sc: Sm/Sc ratios are ~0.1-0.5 times, Na/Sc ratios are 0.05-0.1 time, and Eu/Sc ratios are 0.05-0.4 times H chondrites. EET84302 is classified as a Lodran-like achondrite, but is recognized as being transitional to the Acapulco-like achondrites [1]. Our INAA data show that EET84302 has not lost a silicate partial melt: ratios of Sm/Sc and Na/Sc are ~1 time H chondrites, and Eu/Sc is about 1.8 times H chondrites. In lithophile trace element contents, EET84302 is identical to the Acapulco-like achondrites. Our sample of EET84302 was metal-rich (~40% metal) and chromite-rich (~3% based on INAA and EMPA data), and in this regard is distinct from Acapulco-like achondrites. These modal differences will have no effect on lithophile element ratios, however. References: [1] McCoy et al. (1993) LPS XXIV, 945. [2] McCoy et al. (1992) Meteoritics, 27, 361. [3] Palme et al. (1981) GCA, 45, 727. [4] Schultz et al. (1982) EPSL, 61, 23. [5] Kallemeyn and Wasson (1985) GCA, 49, 261. [6] Kimura et al. (1992) Proc. NIPR Sym. Ant. Met., 5, 165. [7] Bild and Wasson (1976) Min. Mag., 40, 721. [8] Fukuoka et al. (1978) LPS IX, 356.

Field, S. W.; Lindstrom, M. M.; Mittlefehldt, D. W.

1993-07-01

172

3D microscope  

NASA Astrophysics Data System (ADS)

In order to circumvent the fact that only one observer can view the image from a stereoscopic microscope, an attachment was devised for displaying the 3D microscopic image on a large LCD monitor for viewing by multiple observers in real time. The principle of operation, design, fabrication, and performance are presented, along with tolerance measurements relating to the properties of the cellophane half-wave plate used in the design.

Iizuka, Keigo

2008-02-01

173

Holographic microscope interferometer  

NASA Astrophysics Data System (ADS)

A simple and easy to use holographic microscope interferometer (HMI) for biological and material science applications is described. The unit is based on an ordinary microscope accomplished by He-Ne laser, several optical elements, a photothermoplastic (PTP) recorder, and a CCD-camera. Blood and plant cells, as well as internal solid bodies defect images, are demonstrated. Characteristics and application of the unit are discussed.

Babenko, Veronika A.; Konst, Elena V.; Konstantinov, Vladimir B.

1995-02-01

174

Microscopic colitis syndrome.  

PubMed Central

The colorectal biopsy specimens from 30 patients with chronic watery diarrhoea but normal endoscopic and radiographic findings were studied by light microscopy, morphometry, immunohistochemistry, and two patients with electron microscopy. The histological changes in the colorectum were originally diagnosed in six patients as lymphocytic colitis and in 24 patients as collagenous colitis. The analysis of the specimens for this study could delineate three distinct groups of microscopic colitis: lymphocytic colitis (six patients), collagenous colitis without lymphocytic attack on the surface epithelium (seven patients), and a mixed form presenting with both thickening of the collagen plate and increased number of intraepithelial lymphocytes (17 patients). No transformation was seen from one type to another during follow up of six patients for four to seven years. Increased numbers of active pericryptal myofibroblasts were found with the electron microscope in one patient with mixed microscopic colitis showing also myofibroblasts entrapped within the collagen layer. Hitherto undescribed flat mucosa of the ileum was found in one patient with lymphocytic colitis and both flat mucosa and thickening of the collagen plate in the ileum were seen in one patient with the mixed form of the disease. In another patient with mixed microscopic colitis, normalisation of the colorectal morphology occurred after temporary loop ileostomy, followed by the reappearance of both diarrhoea, inflammation, and thickening of the collagen plate after the ileostomy was reversed. No association was found between non-steroid anti-inflammatory drug (NSAID) consumption and collagenous or mixed microscopic colitis. The primary cause of microscopic colitis is probably an immunological reaction to luminal antigen/s, perhaps of ileal origin. The engagement of the pericryptal myofibroblasts in the disease process might result in the development of the various forms of microscopic colitis. An inverse relation between intraepithelial lymphocyte count and collagen thickness may indicate that microscopic colitis is a spectral disease. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Veress, B; Lofberg, R; Bergman, L

1995-01-01

175

[Virtual microscopy in pathology teaching and postgraduate training (continuing education)].  

PubMed

As with conventional microscopy, virtual microscopy permits histological tissue sections to be viewed on a computer screen with a free choice of viewing areas and a wide range of magnifications. This, combined with the possibility of linking virtual microscopy to E-Learning courses, make virtual microscopy an ideal tool for teaching and postgraduate training in pathology. Uses of virtual microscopy in pathology teaching include blended learning with the presentation of digital teaching slides in the internet parallel to presentation in the histology lab, extending student access to histology slides beyond the lab. Other uses are student self-learning in the Internet, as well as the presentation of virtual slides in the classroom with or without replacing real microscopes. Successful integration of virtual microscopy depends on its embedding in the virtual classroom and the creation of interactive E-learning content. Applications derived from this include the use of virtual microscopy in video clips, podcasts, SCORM modules and the presentation of virtual microscopy using interactive whiteboards in the classroom. PMID:18843489

Sinn, H P; Andrulis, M; Mogler, C; Schirmacher, P

2008-11-01

176

Virtual Annotation: Verbal Communication in Virtual Reality.  

National Technical Information Service (NTIS)

This paper describes a system that was developed to explore communication in Virtual Reality. The system offers a simple and powerful method to embed verbal communication in simulations and visualizers by means of voice annotation. Our prototype already d...

J. C. Verlinden J. D. Bolter C. van der Mast

1993-01-01

177

The Sulu UHP Terrane: A Review of the Petrology and Structural Geology  

Microsoft Academic Search

Petrological and isotopic evidence suggests that the protolith of the Sulu ultrahigh-pressure (UHP) terrane was Precambrian continental crust consisting of granite, granodiorite, gabbro, marble, and basic dikes, with local granulite-facies assemblages. Around 220 Ma this unit of continental rocks was buried to depths up of ?120 km within the mantle. Structures formed during exhumation suggest highly mobile behavior of acidic

Simon Wallis; Masaki Enami; Shohei Banno

1999-01-01

178

Geochemical and petrological sampling and studies at the first moon base  

Microsoft Academic Search

Strategic sampling appropriate to the first-order lunar base can advance a variety of first-order lunar geochemical and petrological problems. Field observation and collection of samples would be done on the lunar surface, but detailed analysis would be done mainly in terrestrial laboratories. Among the most important areas of investigation for which field observations can be made and samples can be

L. A. Haskin; R. L. Korotev; D. J. Lindstrom; M. M. Lindstrom

1985-01-01

179

Hardgrove grindability index and petrology used as an enhanced predictor of coal feed rate  

SciTech Connect

An improved predictor of coal pulverization behavior and coal feed rate is under development at the CAER based upon the interaction between Hardgrove Grindability Index (HGI) and coal petrology. With educated attention, this interaction may be a useful tool to enhance coal feed rates if cautiously extended to the mining environment where blends of coal lithotypes are produced.

Hower, J.C. (Univ. of Kentucky, KY (US))

1990-01-01

180

Petrological Constraints on Seismic Properties of the Slave Mantle and its Deep Structure  

Microsoft Academic Search

Mantle xenoliths is one of few major sources of petrological information on the cratonic mantle. This study uses mantle-derived xenoliths of the Slave craton (NWT, Canada) to constrain the thermal state, composition, chemical zoning and seismic properties of the mantle. The Slave peridotites are equilibrated on a cold geotherm characteristic of Archean craton; the SE Slave peridotite is cooler than

M. G. Kopylova

2004-01-01

181

Sedimentary Petrology Field Trip to Gravel Quarry near Rotterdam Junction, NY  

NSDL National Science Digital Library

This is a Stratigraphy Sedimentary Petrology field trip stop at an exceptional glacial outwash gravel quarry, where students measure, identify and count clast types, measure cross-bedding directions, and examine the early stages of lithification of gravel to conglomerate. The gravel deposits are also representative of the local surficial aquifer material that lies nearby in the subsurface.

Ryberg, Paul T.

182

Galapagos hotspot-spreading center system: 1. Spatial petrological and geochemical variations (83°W-101°W)  

Microsoft Academic Search

We report on the petrology and geochemistry of basalts dredged at 40-50 km intervals along the Galapagos Spreading Center, between 83°W and 101°W (40 stations). Emphasis is on spatial variations of `whole rock' major elements, rare earths, trace metals of the first transition series, and the nature of phenocryst assemblages and their abundances. These results provide new constraints on the

J.-G. Schilling; R. H. Kingsley; J. D. Devine

1982-01-01

183

Petrology of seamounts northwest of Samoa and their relation to Samoan volcanism  

Microsoft Academic Search

Petrological and geochemical data on dredged samples from five submarine volcanos northwest of Samoa indicate that three of these volcanos belong to the Samoan volcanic province (Field, Lalla Rookh, and Combe banks), and two belong to separate magmatic zones (Wallis Islands and Alexa Bank). The Samoan volcanic province increases in age westward and both shield-building tholeiitic and alkalic lavas (Combe

Kevin T. M. Johnson; John M. Sinton; Richard C. Price

1986-01-01

184

Issues for application of virtual microscopy to cytoscreening, perspectives based on questionnaire to Japanese cytotechnologists  

Microsoft Academic Search

To clarify the issues associated with the applications of virtual microscopy to the daily cytology slide screening, we conducted a survey at a slide conference of cytology. The survey was conducted specifically to the Japanese cytology technologists who use microscopes on a routine basis. Virtual slides (VS) were prepared from cytology slides using NanoZoomer (Hamamatsu Photonics, Japan), which is capable

Ichiro Mori; Osamu Nunobiki; Takashi Ozaki; Emiko Taniguchi; Kennichi Kakudo

2008-01-01

185

Formation of cratonic lithosphere: An integrated thermal and petrological model  

NASA Astrophysics Data System (ADS)

The formation of cratonic mantle peridotite of Archean age is examined within the time frame of Earth's thermal history, and how it was expressed by temporal variations in magma and residue petrology. Peridotite residues that occupy the lithospheric mantle are rare owing to the effects of melt-rock reaction, metasomatism, and refertilization. Where they are identified, they are very similar to the predicted harzburgite residues of primary magmas of the dominant basalts in greenstone belts, which formed in a non-arc setting (referred to here as "non-arc basalts"). The compositions of these basalts indicate high temperatures of formation that are well-described by the thermal history model of Korenaga. In this model, peridotite residues of extensive ambient mantle melting had the highest Mg-numbers, lowest FeO contents, and lowest densities at ~ 2.5-3.5 Ga. These results are in good agreement with Re-Os ages of kimberlite-hosted cratonic mantle xenoliths and enclosed sulfides, and provide support for the hypothesis of Jordan that low densities of cratonic mantle are a measure of their high preservation potential. Cratonization of the Earth reached its zenith at ~ 2.5-3.5 Ga when ambient mantle was hot and extensive melting produced oceanic crust 30-45 km thick. However, there is a mass imbalance exhibited by the craton-wide distribution of harzburgite residues and the paucity of their complementary magmas that had compositions like the non-arc basalts. We suggest that the problem of the missing basaltic oceanic crust can be resolved by its hydration, cooling and partial transformation to eclogite, which caused foundering of the entire lithosphere. Some of the oceanic crust partially melted during foundering to produce continental crust composed of tonalite-trondhjemite-granodiorite (TTG). The remaining lithosphere gravitationally separated into 1) residual eclogite that continued its descent, and 2) buoyant harzburgite diapirs that rose to underplate cratonic nuclei composed of non-arc basalts and TTG. Finally, assembly of cratonic nuclei into cratons at convergent boundaries substantially modified harzburgite residues by melt-rock reaction.

Herzberg, Claude; Rudnick, Roberta

2012-09-01

186

Testing microscopic discretization  

NASA Astrophysics Data System (ADS)

What can we say about the spectra of a collection of microscopic variables when only their coarse-grained sums are experimentally accessible? In this paper, using the tools and methodology from the study of quantum nonlocality, we develop a mathematical theory of the macroscopic fluctuations generated by ensembles of independent microscopic discrete systems. We provide algorithms to decide which multivariate Gaussian distributions can be approximated by sums of finitely valued random vectors. We study non-trivial cases where the microscopic variables have an unbounded range, as well as asymptotic scenarios with infinitely many macroscopic variables. From a foundational point of view, our results imply that bipartite Gaussian states of light cannot be understood as beams of independent d-dimensional particle pairs. It is also shown that the classical description of certain macroscopic optical experiments, as opposed to the quantum one, requires variables with infinite cardinality spectra.

Navascués, Miguel; Pérez-García, David; Villanueva, Ignacio

2013-03-01

187

Virtual Campus in the Context of an Educational Virtual City  

ERIC Educational Resources Information Center

This paper is focused on virtual campuses, i.e. virtual worlds representing real educational institutions that are based on the metaphor of a university and provide users with different learning tools. More specifically, the idea of integrating a virtual campus into the context of a virtual city is suggested. Such a virtual city, where students…

Fominykh, Mikhail; Prasolova-Forland, Ekaterina; Morozov, Mikhail; Gerasimov, Alexey

2011-01-01

188

MITRE's virtual model shop  

NASA Astrophysics Data System (ADS)

The exploration of visual data and the use of visual information during the design process can be greatly enhanced by working within the virtual environment where the user is closely coupled to the data by means of immersive technologies and natural user interfaces. Current technology enables us to construct a virtual environment utilizing 3D graphics projection, object generated stereo sound, tactile feedback, and voice command input. Advances in software architectures and user interfaces enable us to focus on enhancing the design process within the virtual environment. These explorations at MITRE have evolved into an application which focuses on the ability to create, manipulate, and explore photo and audio realistic 3D models of work spaces, office complexes, and entire communities in real-time. This application, the Virtual Interactive Planning System, is a component of the MITRE virtual model shop, a suite of applications which permits the user to design and manipulate computer graphics models within the virtual environment.

Wingfield, Michael A.

1995-04-01

189

Virtual knots and links  

Microsoft Academic Search

This paper is an introduction to the subject of virtual knot theory and presents a discussion of some new specific theorems\\u000a about virtual knots. The new results are as follows: Using a 3-dimensional topology approach, we prove that if a connected\\u000a sum of two virtual knots K\\u000a 1 and K\\u000a 2 is trivial, then so are both K\\u000a 1 and

Louis H. Kauffman; Vassily Olegovich Manturov

2006-01-01

190

Virtual Knots and Links  

Microsoft Academic Search

This paper is an introduction to the subject of virtual knot theory, combined with a discussion of some specific new theorems about virtual knots. The new results are as follows: We prove, using a 3-dimensional topology approach that if a connected sum of two virtual knots $K_{1}$ and $K_{2}$ is trivial, then so are both $K_{1}$ and $K_{2}$. We establish

Louis Kauffman; Vassily Olegovich Manturov

2005-01-01

191

Virtual classrooms and communities  

Microsoft Academic Search

This paper describes how collaborative technologies, including a corporate intranet, email, videoconferencing, audioconferencing, Internet Relay Chat (IRC), NetMeeting, Virtual Places, WorldsAway, and other Internet-based conferencing tools, can be used to teach classes to geugraphically-dispersed participants. The paper covers the motivation for virtual classrooms, the selection and use of delivery technologies, deployment strategies and issues, participant feedback, and the Virtual University

Lisa Neal

1997-01-01

192

Debugging the virtual machine  

SciTech Connect

A computer program is really nothing more than a virtual machine built to perform a task. The program`s source code expresses abstract constructs using low level language features. When a virtual machine breaks, it can be very difficult to debug because typical debuggers provide only low level machine implementation in formation to the software engineer. We believe that the debugging task can be simplified by introducing aspects of the abstract design into the source code. We introduce OODIE, an object-oriented language extension that allows programmers to specify a virtual debugging environment which includes the design and abstract data types of the virtual machine.

Miller, P.; Pizzi, R.

1994-09-02

193

Nanolithography with Electron Microscopes.  

National Technical Information Service (NTIS)

The use of a Philips Scanning Electron Microscope (PSEM) 500 in making ultra small devices is described. The PSEM 500 is equipped with a pattern generator. Accurate adjustment of the beam is essential for good results. To overcome the poor signal to noise...

1991-01-01

194

Microscopes and ocular infections.  

PubMed

Environmental microbial assays of industrial microscope eyepieces were conducted following reports of multiple intershift ocular infections. Pathogenic Staphylococcus aureus was identified among the microorganisms cultured. This paper suggests that direct contact with industrial microscope eyepieces provides a potentially significant route of transmission of both bacterial and viral ocular infections. An industrial hygiene ocular health questionnaire was distributed to a first and second shift manufacturing operation to assess the incidence of ocular infections. These data were compared to the questionnaire responses of 122 control manufacturing workers who did not use microscopes. Based on self-reporting by employees, those who used microscopes were found to have statistically significant incidence of sites and conjunctivitis that was 8.3 times that of the control group. Sterilization of eyepieces by ethylene oxide, formaldehyde and isopropyl alcohol were considered, but ultimately rejected. These biocides were found respectively to damage ocular lens coatings, contribute to volatile organic emissions, or be ineffective against spore-forming bacteria. This article presents a detailed evaluation of a commercially available ultraviolet sanitization unit (manufactured by the King Bactostat Corp., 7115 Armistad Street, El Paso, TX 79912). This ultraviolet disinfection process proved to be rapid and emission free; it also yielded eyepieces free of residual chemical biocides that have the potential for ocular irritation. Field tests involving 60 eyepieces demonstrated effective disinfection by a Chi-Square statistical comparison, at values greater than 95% confidence level, as compared to unirradiated eyepieces. PMID:3591662

Olcerst, R B

1987-05-01

195

Photography with a Microscope  

Microsoft Academic Search

This beautifully illustrated book describes the methods used to record images viewed through a microscope. The text describes the principles and practices of photomicrography, and is written for all who take photomicrographs, beginners and\\/or experienced practitioners. The authors describe techniques that may be applied to many disciplines for teaching, research, archives, or pleasure. The book includes chapters on standard photography,

Fred Rost; Ron Oldfield

2000-01-01

196

Electron Microscope Aperture System.  

National Technical Information Service (NTIS)

An electron microscope is described, which includes an electron source, a condenser lens having either a circular aperture for focusing a solid cone of electrons onto a specimen or an annular aperture for focusing a hollow cone of electrons onto the speci...

K. Heinemann

1972-01-01

197

Electron Microscope Aperture System.  

National Technical Information Service (NTIS)

An electron microscope is described which includes an electron source, a condenser lens having either a circular aperture for focusing a solid cone of electrons onto a specimen or an annular aperture for focusing a hollow cone of electrons onto the specim...

K. Heinemann

1973-01-01

198

Exploring Tools: Special Microscopes  

NSDL National Science Digital Library

In this activity, learners use a flexible magnet as a model for a scanning probe microscope (SPM). They learn that SPMs are an example of a special tool that scientists use to work on the nanoscale. Use this activity to talk about different tools that scientists use to study the nanoscale.

Network, Nanoscale I.; Sciencenterw

2010-01-01

199

Making Art with Microscopes  

ERIC Educational Resources Information Center

|Interdisciplinary teaching is a great way to focus on overarching concepts and help students make connections across disciplines. Historically, art and science have been connected disciplines. The botanical prints of the 18th and 19th centuries and early work with microscopes are two examples of a need for strong artistic skills in the science…

Benedis-Grab, Gregory

2011-01-01

200

Visualization of confocal microscopic biomolecular data  

NASA Astrophysics Data System (ADS)

Biomolecular visualization facilitates insightful interpretation of molecular structures and complex mechanisms underlying bio-chemical processes. Effective visualization techniques are required to deal with confocal microscopic biomolecular data in which intricate structures, fine features, and obscure patterns might be overlooked without sophisticated data processing and image synthesis. This paper presents major challenges in visualizing confocal microscopic biomolecular data, followed by a survey of related work. We then introduce a case study conducted to investigate the interaction between two proteins contained in a budding yeast saccharomyces cerevisiae by embedding custom modules in Amira. The multi-channel confocal microscopic volume data was first processed using an exponential operator to correct z-drop artifacts introduced during data acquisition. Channel correlation was then exploited to extract the overlap between the proteins as a new channel to represent the interaction while a statistical method was employed to compute the intensity of interaction to locate hot spots. To take advantage of crisp surface representation of region boundaries by iso-surfaces and visually pleasing translucent delineation of dense volumes by volume rendering, we adopted hybrid rendering that incorporates these two methods to display clear-cut protein boundaries, amorphous interior materials, and the scattered interaction in the same view volume with suppressed and highlighted parts selected by the user. The highlighted overlap helped biologists learn where the interaction happens and how it spreads, particularly when the volume was investigated in an immersive Cave Automatic Virtual Environment (CAVE) for intuitive comprehension of the data.

Liu, Zhanping; Moorhead, Robert J., II

2005-04-01

201

Petrology, diagnosis, and sedimentology of oil reservoirs in Upper Cretaceous Shannon Sandstone Beds, Powder River basin, Wyoming  

SciTech Connect

This paper reports on a study of the petrology of the Shannon Sandstone Member that indicates diagenetic alterations of outcrop and near-surface sandstones cannot be used to predict the diagenesis of deeply buried sandstones. Textural relations show that oil migrated to reservoirs late in the postdepositional history of the Shannon. Petrologic and sedimentologic data suggest that an alternative depositional model (for example, a nearshore rather than mid-shelf setting) should be considered for the Shannon.

Hansley, P.L.; Whitney, C.G.

1990-01-01

202

Using Observations to Interpret Magma Processes in the Sierra Nevada: An Undergraduate Petrology Laboratory Exercise  

NASA Astrophysics Data System (ADS)

Undergraduate igneous and metamorphic petrology is often one of the few courses in which students use field, thin section, hand sample and geochemical observations to interpret a suite of related rocks. Many students may not have encountered the idea of separating observation from interpretation prior to petrology; yet being able to distinguish these is an important skill for any budding petrologist to learn. Labs that require students to integrate abstract concepts from the lecture portion of the course to present a coherent story based on observations are essential to producing students that are well versed in petrology. A capstone-type lab allows students use many of their recently acquired skills to solve real problems in petrology. These integrated labs can take a number of forms from a short lab looking at a few related thin sections, to a multi-week lab with specified tasks, to a semester-long project culminating in a paper or a presentation. For the past few years, I have used a suite of rocks from the Sierra Nevada batholith to give petrology students a capstone experience for the igneous portion of the course. Students are given thin sections with hand samples, a map and a table of geochemical analyses and asked to record hand-sample and thin section observations with the idea that these will be used to understand processes that were active during batholith generation. Because students are given geochemical analyses, they are also expected to experiment with the use of graphs (e.g., Harker and spider diagrams) to better understand tables of geochemical analyses. The students use observations about rocks and geochemistry to build a coherent story around these rocks; the final product is a short paper in which they use petrographic observations and geochemical diagrams to back up their interpretations. Although the lab presented is specifically designed around a set of thin sections housed at the University of Wisconsin Oshkosh for an upper level course, the lab is highly adaptable. I present some options for adapting this lab to any set of thin sections and hand samples with associated geochemical analyses. This lab can also be tailored to a variety of skill levels - from 2nd year introductory petrology to a graduate course.

Wenner, J. M.

2003-12-01

203

The role of petrology in defining volcanic hazards and designing monitoring systems  

NASA Astrophysics Data System (ADS)

Petrology is the study of magmatic systems; physical volcanology investigates processes of eruption. Physical volcanology provides the pre-eminent underpinning of the practical business of defining hazard scenarios, planning mitigation and designing monitoring strategies. Recent research in a variety of volcanic settings has demonstrated an important link between the petrologic processes that at a fundamental level drive the behavior of volcanoes and the processes that determine the eruptive style of a volcano. Together these define the hazards that arise from volcanic eruptions. Petrological studies of volcanoes are typically based on a study of lava because coherent rock is less vulnerable to weathering and alteration and is more durable in the geological record. Pyroclastic materials are commonly friable and glassy, are more easily eroded, and are more difficult to use in the analytical techniques that have become the staple basis of petrological studies. However, pyroclastic materials represent a complementary but different part of the magmatic story and it is only by integrating both effusive and explosive components of an eruption sequence that a complete picture of the behavior of the system feeding a volcano can be gained. Andesitic strato-cones are made up of a cone-building facies consisting mainly of primary magmatic products and usually dominated by lava flows because pyroclastic material is easily eroded from the slopes of a steep cone. The surrounding ring plain facies includes primary pyroclastic deposits but is typically dominated by redistributed material in the form of debris flow and lahar deposits together with reworked fluvial material. The deposits of each of these two facies are assembled on different time scales and they contain different aspects of the record of the evolution of the magmatic system that gave rise to them. An important practical consequence of this is that different parts of the geochemical record of the system can occur in different parts of the volcano. Integrated petrological and volcanological studies on the andesite volcanoes of northern New Zealand have identified repeated cycles of deep seated behavior that translate directly into patterns in eruptive behavior. Further, it has been possible to define long term petrological evolutionary trends which provide a framework for understanding shorter term cycles. On an even shorter time scale the flux of magma through the near vent environment can be investigated by means of the stabilities of mineral phases vulnerable to variable cooling rates. Thus the fundamental behavior of andesitic volcanoes as defined by an understanding of the underlying magmatic system can provide the foundation for robust probabilistic time-varying hazard forecasts as well as strategies for monitoring potentially active volcanoes.

Smith, I. E.; Turner, M. B.; Price, R. C.; Cronin, S. J.

2011-12-01

204

Toward Virtual Humans  

Microsoft Academic Search

This paper describes the virtual humans developed as part of the Mission Rehearsal Exercise project, a virtual reality-based training system. This project is an ambitious exercise in integration, both in the sense of integrating technology with entertainment industry content, but also in that we have joined a number of component technologies that have not been integrated before. This integration has

William R. Swartout; Jonathan Gratch; Randall W. Hill Jr.; Eduard H. Hovy; Stacy Marsella; Jeff Rickel; David R. Traum

2006-01-01

205

10 Myths of Virtualization  

ERIC Educational Resources Information Center

|Half of servers in higher ed are virtualized. But that number's not high enough for Link Alander, interim vice chancellor and CIO at the Lone Star College System (Texas). He aspires to see 100 percent of the system's infrastructure requirements delivered as IT services from its own virtualized data centers or other cloud-based operators. Back in…

Schaffhauser, Dian

2012-01-01

206

State Virtual Libraries  

ERIC Educational Resources Information Center

|Virtual library? Electronic library? Digital library? Online information network? These all apply to the growing number of Web-based resource collections managed by consortiums of state library entities. Some, like "INFOhio" and "KYVL" ("Kentucky Virtual Library"), have been available for a few years, but others are just starting. Searching for…

Pappas, Marjorie L.

2003-01-01

207

A Virtual Good Idea  

ERIC Educational Resources Information Center

|School districts across the country have always had to do more with less. Funding goes only so far, leaving administrators and IT staff to find innovative ways to save money while maintaining a high level of academic quality. Creating virtual servers accomplishes both tasks, district technology personnel say. Virtual environments not only allow…

Bolch, Matt

2009-01-01

208

Government Virtual Service Networks  

Microsoft Academic Search

Governments and their partners have developed sophisticated networks of services to comprehensively reach their common customers. Those networks developed to reach the citizen in the physical world should be extended to reach citizens in the virtual world. Virtual networks should stretch from government agencies to public portals, through public or private service providers and fully leveraging the Internet as a

Mauro Regio

2002-01-01

209

Virtual Classes, Real Policy  

ERIC Educational Resources Information Center

|As Internet technology encroached on the public school classroom about a decade ago, Kim Ross, superintendent of the Houston (MN) School District saw an opportunity. The entrepreneurial spirit overtook Ross and his team, and out of that was born the Minnesota Virtual Academy and the Minnesota Center of Online Learning, or MCoOL--two virtual

Beem, Kate

2010-01-01

210

Virtual World of Learning  

ERIC Educational Resources Information Center

|The United States has many lessons it can learn from how other countries are deploying virtual education and how it might partner up with those countries in different ways to offer a wider range of educational and cultural experiences to its students. This report, part of "Education Week's" ongoing series on virtual education, draws out many of…

Flanigan, Robin L.; Ash, Katie; Davis, Michelle R.; Quillen, Ian

2012-01-01

211

Virtual german cockroach  

NSDL National Science Digital Library

3D virtual image of a German Cockroach (Family Blattidae). This movie is also available as a Virtual Reality Modeling Language (VRML) model. The VRML models are more interactive than the QuickTime versions, but special software may need to be downloaded to open them (read the ÃÂHelpÃÂ page for details). Those people using public computers may be limited from fully accessing the resource. Mozilla Firefox users can view the VRML files directly in their browsers by downloading the Cortona extension (http://www.parallelgraphics.com/products/cortona/download/netscape/). This website is an excellent educational resource for all ages. The Virtual Insects home page (http://www.ento.vt.edu/~sharov/3d/3dinsect.html) has a basic explanation of how virtual reality works, including the Virtual Reality Modeling Language. The "Virtual Images" link takes you to a list of insects that can be viewed as 3D digital reconstructions. The image files would make excellent additions to teaching lectures for introductory classes. Visit the "How to Build Virtual Insects" page to read about how the images were created and how the original models were made more biologically accurate. Also be sure to read the page on how to view the cyber-insects inside a virtual reality "cave".

0002-11-30

212

Virtual Data Visualizer  

Microsoft Academic Search

Te authors present the Virtual Data Visualizer, a highly interactive, immersive environment for visualizing and analyzing data. VDV is a set of tools for exploratory data visualization that does not focus on just one type of application. It employs a data organization with data arranged hierarchically in classes that can be modified by the user within the virtual environment. The

Ron Van Teylingen; William Ribarsky; Charles Van Der Mast

1997-01-01

213

Virtual Reality and Psychotherapy  

Microsoft Academic Search

Virtual Reality (VR) is a new technology consisting on a graphic environment in which the user, not only has the feeling of being physically present in a virtual world, but he\\/she can interact with it. The first VR workstations were designed for big companies in order to create environments that simulate certain situations to train professionals. However, at this moment

Cristina BOTELLA; Soledad QUERO; Rosa M. BAÑOS; Conxa PERPIÑÁ; Azucena GARCÍA PALACIOS

214

Virtual clay modeling system  

Microsoft Academic Search

This paper describes a CAD system in which a user can directly manipulate the shape of a virtual object like a clay model and can produce its solid model data. The key component of its hardware is a special input device with a 3D position tracker and a tactile sensor. In this system, the movement of a virtual object is

Ken-ichi Kameyama

1997-01-01

215

Virtual orthopedic surgery training  

Microsoft Academic Search

Medicine is one of the most promising areas for emerging computer graphics and virtual reality techniques. VR training simulators let surgeons practice on virtual body tissue and get the same feedback they would experience in performing a real operation. Hybrid VR systems permit medical practitioners to view the patient overlaid with 3D data sets derived from 3D scanners, thus providing

A. Sourin; O. Sourina; Howe Tet Sen

2000-01-01

216

Virtual Worlds for Educators  

ERIC Educational Resources Information Center

|This article describes an online experience that has not only created a fantasy world for the general public but has enabled some tech-savvy educators to create virtual educational opportunities. Second Life, or SL, is a 3-D Internet-based virtual world created by Linden Lab and populated by nearly 1,000,000 active users worldwide since 2003.…

Dembo, Steve

2008-01-01

217

Collaborative Distributed Virtual Sculpting  

Microsoft Academic Search

A lot of effort is now being put into developing collabo- rative distributed virtual environments. Howevel; very few projects address collaborative virtual sculpting in which the shapes of the target objects are likely changing continu- ously. Some major issues including user interaction, data transmission, concurrent object editing by multiple clients and rendering of deforming objects must be addressed in a

Frederick W. B. Li; Rynson W. H. Lau; Frederick F. C. Ng

2001-01-01

218

Improving Virtual Team Communication  

Microsoft Academic Search

The foundation of successful software product development today is establishing an effective and efficient teamwork. In order to manage large software development projects it is needed to manage and coordinate virtual teams of programmers, engineers, business analysts and other project stakeholders. Trust is required for effective team communication. Presented software tool enhances cooperative work support by improving virtual team communication.

Kresimir Pripuzic; Luko Gjenero; Hrvoje Belani

2006-01-01

219

Results of new petrologic and remote sensing studies in the Big Bend region  

NASA Astrophysics Data System (ADS)

The initial section of this manuscript involves the South Rim Formation, a series of 32.2-32 Ma comenditic quartz trachytic-rhyolitic volcanics and associated intrusives, erupted and was emplaced in Big Bend National Park, Texas. Magmatic parameters have only been interpreted for one of the two diverse petrogenetic suites comprising this formation. Here, new mineralogic data for the South Rim Formation rocks are presented. Magmatic parameters interpreted from these data assist in deciphering lithospheric characteristics during the mid-Tertiary. Results indicate low temperatures (< 750 °C), reduced conditions (generally below the FMQ buffer), and low pressures (? 100 MPa) associated with South Rim Formation magmatism with slight conditional differences between the two suites. Newly discovered fayalite microphenocrysts allowed determination of oxygen fugacity values (between -0.14 and -0.25 DeltaFMQ over temperature ranges of 680-700 °C), via mineral equilibria based QUILF95 calculations, for Emory Peak Suite. Petrologic information is correlated with structural evidence from Trans-Pecos Texas and adjacent regions to evaluate debated timing of tectonic transition (Laramide compression to Basin and Range extension) and onset of the southern Rio Grande Rift during the mid-Tertiary. The A-type and peralkaline characteristics of the South Rim Formation and other pre-31 Ma magmatism in Trans-Pecos Texas, in addition to evidence implying earlier Rio Grande Rift onset in Colorado and New Mexico, promotes a near-neutral to transtensional setting in Trans-Pecos Texas by 32 Ma. This idea sharply contrasts with interpretations of tectonic compression and arc-related magmatism until 31 Ma as suggested by some authors. However, evidence discussed cannot preclude a pre-36 Ma proposed by other authors. The later section of this manuscript involves research in the Big Bend area using Google Earth. At present there is high interest in using Google Earth in a variety of scientific investigations. However, program developers have disclosed limited information concerning the program and its accuracy. While some authors have attempted to independently constrain the accuracy of Google Earth, their results have potentially lost validity through time due to technological advances and updates to imagery archives. For this reason we attempt to constrain more current horizontal and vertical position accuracies for the Big Bend region of West Texas. In Google Earth a series of 268 data points were virtually traced along various early Tertiary unconformities in Big Bend National Park and Big Bend Ranch State Park. These data points were compared with high precision GPS measurements collected in field and yielded a horizontal position accuracy of 2.64 meters RMSE. Complications arose in determining vertical position accuracy for Google Earth because default keyhole markup language (.kml) files currently do not export elevation data. This drawback forces users to hand record and manually input elevation values listed on screen. This is a significant handicap rendering Google Earth data useless with larger datasets. However, in a workaround solution exempted elevation values can be replaced from other data sources based on Google Earth horizontal positioning. We used Fledermaus 3D three-dimensional visualization software to drape Google Earth horizontal positions over a National Elevation Dataset (NED) digital elevation map (DEM) in order to adopt a large set of elevation data. A vertical position accuracy of 1.63 meters RMSE was determined between 268 Google Earth data points and the NED. Since determined accuracies were considerably lower than those reported in previous investigations, we devoted a later portion of this investigation to testing Google Earth-NED data in paleo-surface modeling of the Big Bend region. An 18 x 30 kilometer area in easternmost Big Ranch State Park was selected to create a post-Laramide paleo-surface model via interpolation of approximately 2900 Google Earth-NED data points representing sections of an early Tertiary

Benker, Stevan Christian

220

Trusted Virtual Disk Images  

NASA Astrophysics Data System (ADS)

Many solutions have been proposed to raise the security level of virtualisation. However, most overlook the security of virtual disk images. With our paper we present a secure, flexible and transparent security architecture for virtual disk images. Virtual machines running on our architecture transparently benefit from confidentiality and integrity assurance. We achieve this by incorporating the concepts of Trusted Computing and in particular the Trusted Platform Module (TPM). This enables us to provide a secure and flexible trusted virtual disk infrastructure to a broad number of platforms. Furthermore, the unique concept of Trusted Virtual Disk Images (TVDI) allows an image owner to stay in control over the disk image throughout its complete life-cycle.

Gebhardt, Carlo; Tomlinson, Allan

221

The portable virtual simulator.  

PubMed

The Virtual Simulator is a software tool for support and management of the geometric component of 3-dimensional radiotherapy treatment design. The Virtual Simulator is a software implementation of a physical simulator with additional functionality not currently available on physical simulators. Treatment of a virtual patient, derived from CT or other source, is simulated using the Virtual Simulator in the same way a physical simulator would be used. The intent of this approach is to provide the user with a familiar working environment for radiotherapy treatment design. Key features include an effective and efficient user interface, and the use of computing techniques and software standards which enhance portability to a variety of computer workstations. The Virtual Simulator is implemented in the C programming language using the X Window System, and has been written with the generic UNIX workstation in mind. It has been demonstrated that it can be installed and run without modification on workstations from a number of vendors. PMID:2061124

Sherouse, G W; Chaney, E L

1991-07-01

222

Femtosecond scanning tunneling microscope  

SciTech Connect

This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). By combining scanning tunneling microscopy with ultrafast optical techniques we have developed a novel tool to probe phenomena on atomic time and length scales. We have built and characterized an ultrafast scanning tunneling microscope in terms of temporal resolution, sensitivity and dynamic range. Using a novel photoconductive low-temperature-grown GaAs tip, we have achieved a temporal resolution of 1.5 picoseconds and a spatial resolution of 10 nanometers. This scanning tunneling microscope has both cryogenic and ultra-high vacuum capabilities, enabling the study of a wide range of important scientific problems.

Taylor, A.J.; Donati, G.P.; Rodriguez, G.; Gosnell, T.R.; Trugman, S.A.; Some, D.I.

1998-11-01

223

Ion photon emission microscope  

DOEpatents

An ion beam analysis system that creates microscopic multidimensional image maps of the effects of high energy ions from an unfocussed source upon a sample by correlating the exact entry point of an ion into a sample by projection imaging of the ion-induced photons emitted at that point with a signal from a detector that measures the interaction of that ion within the sample. The emitted photons are collected in the lens system of a conventional optical microscope, and projected on the image plane of a high resolution single photon position sensitive detector. Position signals from this photon detector are then correlated in time with electrical effects, including the malfunction of digital circuits, detected within the sample that were caused by the individual ion that created these photons initially.

Doyle, Barney L. (Albuquerque, NM)

2003-04-22

224

Measuring the profile and out-of-plane motion of microstructures using microscopic interferometry with FTM analysis  

Microsoft Academic Search

Microscopic interferometry is up to now the most widely used technique for microstructure surface profiling, and is also capable of measuring out-of-plane motion and deflection of microstructures with stroboscopic illumination. In this paper we put forward a stroboscopic Mirau microscopic interferometer system, which is built of commercially available components and instruments based on virtual instrument technology. An improved Fourier transform

Xiaodong Hu; Gang Liu; Tong Guo; Chunguang Hu; Xiaotang Hu

2006-01-01

225

Microscopic models of hardness  

Microsoft Academic Search

Recent developments in the field of microscopic hardness models have been reviewed. In these models, the theoretical hardness\\u000a is described as a function of the bond density and bond strength. The bond strength may be characterized by energy gap, reference\\u000a potential, electron-holding energy or Gibbs free energy, and different expressions of bond strength may lead to different\\u000a hardness models. In

F. M. Gao; L. H. Gao

2010-01-01

226

The Transmission Electron Microscope  

Microsoft Academic Search

\\u000a A typical commercial transmission electron microscope (TEM) costs about 5 for each electron volt (eV) of energy in the beam and, if you add on all available options, it can easily cost up to5 for each electron volt (eV) of energy in the beam\\u000a and, if you add on all available options, it can easily cost up to 10 per

David B. Williams; C. Barry Carter

227

Virtual Sailor: Synthetic Humans for Virtual Environments.  

National Technical Information Service (NTIS)

In many virtual environment (VE) applications, e.g., a VE system for training personnel to perform multi-person maintenance tasks, the VE System must be able to display accurate models of human figures that can perform routine behaviors and adapt to event...

D. L. Zeltzer

1995-01-01

228

MinChem: A Prototype Petrologic Database for Hanford Site Sediments  

SciTech Connect

A prototype petrologic database (MinChem) has been under continual development for several years. MinChem contains petrologic, mineralogical, and bulk-rock geochemical data for Hanford Site sediments collected over multiple decades. The database is in relational form and consists of a series of related tables modeled after the Hanford Environmental Information System HEIS (BHI 2002) structures. The HEIS-compatible tables were created in anticipation of eventual migration into HEIS, or some future form of HEIS (e.g. HEIS-GEO). There are currently a total of 13,129 results in MinChem from 521 samples collected at 381 different sampling sites. These data come from 19 different original source documents published and unpublished (e.g. letter reports) between 1976 and 2009. The data in MinChem consist of results from analytical methods such as optical and electron microscopy, x-ray diffraction, x-ray fluorescence, and electron probe microanalysis.

Mackley, Rob D.; Last, George V.; Serkowski, John A.; Middleton, Lisa A.; Cantrell, Kirk J.

2010-09-01

229

Constraints on chondrule origin from petrology of isotopically characterized chondrules in the Allende meteorite  

SciTech Connect

The petrologic and chemical properties of the ferromagnesian chondrules in the Allende carbonaceous chondrite were examined in terms of the isotopic composition and the correlations between isotopic patterns. Areas of thin sections were studied with a SEM and bulk chemical fractions of 12 constituents were quantified to calculate correlations with petrologic features. A possible correlation between (CaO + Al2O2)/MgO and oxygen isotopes imply the formation of oxygen isotopic compositions in the chondrules by exchanges between isotopically heavy nebular gases and O-16 enriched solids. Different rates of gaseous exchange occurred with the various types of chondrules. Factors which may have controlled the exchanges are discussed. 21 references.

Mcsween, H.Y. Jr.

1985-09-01

230

Fractal approach in petrology: Small-angle neutron scattering experiments with volcanic rocks  

SciTech Connect

Following Mandelbrot's pioneering work in 1977, we attempt to use the concept of fractal dimension in petrology. Fractal dimension is an intensive property of matter which offers a quantitative measure of the degree of surface roughness. Neutron scattering experiments have been performed on 18 volcanic rocks from different localities. The scattered intensity as a function of the momentum transfer obeys a power law whose exponent varies, for the rock samples presented, between -3 and -4. We conclude that, at the molecular level, our volcanic rocks are not fractal volumes. With regard to the particle-matrix interface, it is not possible to provide a determination at the present stage of research. Our findings suggest it is feasible to verify the degree of surface irregularity at a resolution which is relevant to many aspects of petrology.

Lucido, G.; Triolo, R.; Caponetti, E.

1988-11-01

231

Crustal structure beneath Montserrat, Lesser Antilles, constrained by xenoliths, seismic velocity structure and petrology  

NASA Astrophysics Data System (ADS)

Noritic anorthosite, gabbroic anorthosite and hornblende-gabbro xenoliths are ubiquitous in the host andesite at Montserrat. Other xenoliths include quartz diorite, metamorphosed biotite-gabbro, plagioclase-hornblendite and plagioclase-clinopyroxenite. Mineral compositions suggest a majority of the xenoliths are cognate. Cumulate, hypabyssal and crescumulate textures are present. A majority of the xenoliths are estimated to have seismic velocities of 6.7-7.0 km/s for pore-free assemblages. These estimates are used in conjunction with petrological models to constrain the SEA CALIPSO seismic data and the structure of the crust beneath Montserrat. Andesitic upper crust is interpreted to overlie a lower crust dominated by amphibole and plagioclase. Xenolith textures and seismic data indicate the presence of hypabyssal intrusions in the shallow crust. The structure of the crust is consistent with petrological models indicating that fractionation is the dominant process producing andesite at Montserrat.

Kiddle, E. J.; Edwards, B. R.; Loughlin, S. C.; Petterson, M.; Sparks, R. S. J.; Voight, B.

2010-04-01

232

Quantitative and Qualitative Changes in Teaching Histology by Means of Virtual Microscopy In an Introductory Course in Human Anatomy  

NSDL National Science Digital Library

This article describes a study investigating the learning impact of using virtual microscopy versus the tradition optical microscope in an undergraduate anatomy course. The study used lab averages, individual test scores, and survey results to compare differences.

Polly Husmann (Indiana University School of Medicine Medical Sciences Program); PhD Valerie Dean O'Loughlin (Indiana University Medical Sciences Program)

2009-09-14

233

Acapulco and Lodran-like achondrites: Petrology, geochemistry, chronology, and origin  

Microsoft Academic Search

We have performed petrologic and geochemical studies of five primitive achondrites: ALHA81187 and ALHA81261 (Acapulco-like), EET 84302 (transitional, but Acapulco-like), and LEW 88280 and MAC 88177 (Lodran-like). We have also performed 39Ar-40Ar chronology on ALHA81187, ALHA81261, and EET 84302. LEW 88280 and MAC 88177 contain more ferroan olivines, orthopyroxenes, clinopyroxenes, and chromites than do the Acapulco-like achondrites. Plagioclase is present

David W. Mittlefehldt; Marilyn M. Lindstrom; Donald D. Bogard; Daniel H. Garrison; Stephen W. Field

1996-01-01

234

The EarthChem Deep Lithosphere Dataset: Digital Access to Mantle Xenolith Petrological Data  

Microsoft Academic Search

Establishment of a geologic framework for the USArray mission of EarthScope largely depends on community efforts that facilitate the integration of seismic data with petrologic, gravity, structural, and other geologic data. The EarthChem federation of interoperable databases (www.earthchem.org) provides cyberinfrastructure in which large geochemical data collections are assembled and curated to maximize data usability and accessibility. In an effort to

K. A. Block; K. A. Lehnert; J. D. Walker; A. Fishman; W. F. McDonough

2006-01-01

235

Petrology and geochemistry of peridotite xenoliths from the Letlhakane kimberlites, Botswana  

Microsoft Academic Search

The diamondiferous Letlhakane kimberlites are intruded into the Proterozoic Magondi Belt of Botswana. Given the general correlation\\u000a of diamondiferous kimberlites with Archaean cratons, the apparent tectonic setting of these kimberlites is somewhat anomalous.\\u000a Xenoliths in kimberlite diatremes provide a window into the underlying crust and upper mantle and, with the aid of detailed\\u000a petrological and geochemical study, can help unravel

Johann Stiefenhofer; K. S. Viljoen; J. S. Marsh

1997-01-01

236

Petrology/Geochemistry/Mineralogy/Structure of Shear zones in St. Lawrence County  

NSDL National Science Digital Library

These rocks were collected from outcrops frequented by structural geology field trips. CCM 42 is from the town of Clare, CCM 43 is from Russell; although labeled CCM, neither is from the Carthoage Colton Mylonite Zone, but both are from shear zones. DEK is from the world famous DeKalb anticline. In this lab we try to pull together material from petrology, geochemistry, mineralogy and structure.

Badger, Robert

237

A concise compilation of petrologic information on possibly pristine nonmare Moon rocks  

Microsoft Academic Search

Ansrn.q.cr To facilitate systematic study of the surviving compositionally pristine (endogenously igneous) rocks of the ancient lunar crust, a compilation has been generated of all likely samples, along with key information on the petrologic characteristics and chemistry of each sample. The compilation includes 260 samples. Besides information related to the likelihood of each sample being truly pristine (i.e., mainly its

H. W. LnnBN

238

The EarthChem Deep Lithosphere Dataset: Digital Access to Mantle Xenolith Petrological Data  

NASA Astrophysics Data System (ADS)

Establishment of a geologic framework for the USArray mission of EarthScope largely depends on community efforts that facilitate the integration of seismic data with petrologic, gravity, structural, and other geologic data. The EarthChem federation of interoperable databases (www.earthchem.org) provides cyberinfrastructure in which large geochemical data collections are assembled and curated to maximize data usability and accessibility. In an effort to address the needs of the GeoFrame/USArray community, EarthChem is developing the Deep Lithosphere Petrological Dataset to provide easy access to an integrated, comprehensive, global set of petrological data from upper mantle and lower crustal rocks. The initial focus for EarthChem's Deep Lithosphere dataset is xenolith data from geographic locations identified by GeoFrame as relevant to the USArray mission. Data are compiled in a relational database that complements the data collections of NAVDAT, GEOROC, and PetDB, and which together can be accessed and downloaded through the EarthChem Portal. The web interface permits the user to query by sample location, rock type, mineral, inclusion, author, major oxide, trace element and isotopic composition to build customized datasets. Additionally, radiometric age, host rock information, and model data such as pressure and temperature, including information about the geobarometer/geothermometer used by authors in their calculations, are included in the dataset to provide the perspective of geochemical modeling on the nature of the sub-continental mantle and lower crust for correlation with seismic imaging and geodynamic modeling.

Block, K. A.; Lehnert, K. A.; Walker, J. D.; Fishman, A.; McDonough, W. F.

2006-12-01

239

4-H Virtual Farm  

NSDL National Science Digital Library

The 4-H Virtual Farm offers sections on horses, farm pond aquaculture, beef, dairy, poultry, and wheat. Each section has an interview with a producer about their work, information on the industry in Virginia, animations of farm processes, a virtual reality view of a farm, information on what the producers must know and how they use science, explanations of the food chain, a glossary for students to learn to talk like a producer, and a quiz for a chance to win virtual blue ribbons.

240

Science Nation: Virtual Self  

NSDL National Science Digital Library

An avatar is a movable image that people design to represent themselves in virtual reality environments or in cyberspace. Avatars are usually for fun and games but could avatars actually change us? Jeremy Bailenson thinks so. With support from the National Science Foundation (NSF), he created the Virtual Human Interaction Lab (VHIL) at Stanford University to study, among other things, the power avatars exert on their real world masters. Sometimes, avatars are designed to be ideal versions of their creators, and there's now evidence that the virtual reality persona begins to influence the real life persona.

241

Virtually there, almost: educational and informational possibilities in virtual worlds  

Microsoft Academic Search

Purpose – The purpose of this article is to analyze the educational and more specifically, the library and information opportunities afforded through virtual worlds such as Second Life. Design\\/methodology\\/approach – The article provides an analysis of virtual world opportunities through a review of relevant literature as well as actual applications of virtual world platforms. Findings – Virtual worlds have the

Peter Edward Sidorko

2009-01-01

242

Positron Reaction Microscope  

NASA Astrophysics Data System (ADS)

We are developing a positron reaction microscope to measure kinematically complete ionization reactions of atoms and dissociative ionization of simple molecules by positron impact. The experiment is designed to use the slow positron beamline at the ARC Centre for Antimatter Matter Studies (CAMS) node at the Australian National University (ANU). This project is a collaboration among the University of North Texas, CAMS, and the Max Planck Insitute for Kern Phyzik in Heidelberg. Initial measurements and apparatus calibration will be performed using electrons. For positron measurements, the apparatus will be rolled into position on the slow positron beamline at the CAMS site at ANU.

Mueller, Dennis; Armitage, Simon; Vermet, Corbin; Lee, Chistopher; Dorn, Alexander; Buckman, Stephen; Sullivan, James

2012-10-01

243

Microscopes/microprobes  

NASA Astrophysics Data System (ADS)

Our new pulsed positron microbeam is not only a microprobe for the local analysis of defect characteristics but also a microscope providing a complete lifetime image of defect distributions at micron resolution. Both aspects are discussed with examples from recent applications to basic problems of materials research. For fundamental reasons an image of defects at nanometer resolution by the present generation of microbeams is impossible. Therefore, a more advanced dual microbeam system will be proposed, where the defects are stained with positrons. Then a scanned electron beam with nanometer spot size is sensitive to the stained defects.

Kögel, G.

2002-06-01

244

Solid state optical microscope  

DOEpatents

A solid state optical microscope wherein wide-field and high-resolution images of an object are produced at a rapid rate by utilizing conventional optics with a charge-coupled photodiode array. A galvanometer scanning mirror, for scanning in one of two orthogonal directions is provided, while the charge-coupled photodiode array scans in the other orthogonal direction. Illumination light from the object is incident upon the photodiodes, creating packets of electrons (signals) which are representative of the illuminated object. The signals are then processed, stored in a memory, and finally displayed as a video signal. 2 figs.

Young, I.T.

1983-08-09

245

Low frequency acoustic microscope  

DOEpatents

A scanning acoustic microscope is disclosed for the detection and location of near surface flaws, inclusions or voids in a solid sample material. A focused beam of acoustic energy is directed at the sample with its focal plane at the subsurface flaw, inclusion or void location. The sample is scanned with the beam. Detected acoustic energy specularly reflected and mode converted at the surface of the sample and acoustic energy reflected by subsurface flaws, inclusions or voids at the focal plane are used for generating an interference signal which is processed and forms a signal indicative of the subsurface flaws, inclusions or voids.

Khuri-Yakub, Butrus T. (Palo Alto, CA)

1986-11-04

246

Virtual Lava Tube  

NSDL National Science Digital Library

This interactive resource adapted from The Virtual Lava Tube by Dave Bunnell, presents images of different features found in lava tube caves and includes detailed information on how these features are formed and where they occur.

Foundation, Wgbh E.

2005-10-21

247

Virtual Organizations: An Overview  

NASA Astrophysics Data System (ADS)

The need to remain competitive in the open market forces companies to concentrate on their core competencies while searching for alliances when additional skills or resources are needed to fulfill business opportunities. The changing business situation of companies and customer needs have motivated researchers to introduce Virtual Organization (VO) idea. A Virtual Organization is always a form of partnership and managing partners and handling partnerships are crucial. Virtual organizations are defined as a temporary collection of enterprises that cooperate and share resources, knowledge, and competencies to better respond to business opportunities. This paper presents base concepts of virtual organizations including properties, management concepts, operational concepts, and main issues in collaboration such as security and authentication.

Nami, Mohammad Reza

248

Virtual Field Trips  

NSDL National Science Digital Library

These virtual field trips allow students to explore plant and animal life in South CarolinaâÂÂs ecosystemsâÂÂa cove forest and a salt marshâÂÂand to understand the threats to these fragile systems.

Barbara Jean Speziale (Clemson University;)

2010-06-18

249

Coaxial Virtual Cathode Enhancement.  

National Technical Information Service (NTIS)

Traditionally, the radiated microwave frequency in a coaxial vircator is considered to be determined primarily by the virtual cathode oscillation frequency and the electron reflection frequency. In this paper, some experiments showing different results ar...

M. Kristiansen J. Mankowski

2004-01-01

250

Deeply Virtual Neutrino Scattering.  

National Technical Information Service (NTIS)

We investigate the extension of the deeply virtual Compton scattering process into the weak interaction sector. Standard electromagnetic Compton scattering provides a unique tool for studying hadrons, which is one of the most fascinating frontiers of mode...

A. Psaker

2007-01-01

251

Synchronization in Virtual Realities  

Microsoft Academic Search

Interactive graphics, and especially virtual reality systems, require synchroniza- tion of sight, sound, and user motion if they are to be convincing and natural. We present a solution to the synchronization problem that is based on optimal estimation methods.

Martin Friedmann; Thad Starner; Alex Pentland

1992-01-01

252

Virtual Worlds: Considering Standards.  

National Technical Information Service (NTIS)

PURPOSE AND SCOPE: Stimulate high-level discussion on issues in virtual worlds interoperability and standards * Collect feedback for further consideration. CRUX OF THE MATTER: Leveraging lessons learned may encourage evolutionary advancement and increase ...

K. Gamor

2009-01-01

253

Direct manipulation of virtual objects  

Microsoft Academic Search

Interacting with a Virtual Environment (VE) generally requires the user to correctly perceive the relative position and orientation of virtual objects. For applications requiring interaction in personal space, the user may also need to accurately judge the position of the virtual object relative to that of a real object, for example, a virtual button and the user's real hand. This

Long K. Nguyen

2009-01-01

254

[Virtual + 1] * Reality  

Microsoft Academic Search

\\u000a Virtual Reality aims at creating an artificial environment that can be perceived as a substitute to a real setting. Much effort\\u000a in research and development goes into the creation of virtual environments that in their majority are perceivable only by\\u000a eyes and hands. The multisensory nature of our perception, however, allows and, arguably, also expects more than that. As\\u000a long

Steffi Beckhaus

2011-01-01

255

Introducing Virtual Travel  

Microsoft Academic Search

\\u000a This chapter explores issues and consequences associated with travel and tourism. We examine the disastrous effects of tourism\\u000a on sites around the world, from England to South America, the issue of air travel, and missing opportunities for learning\\u000a once one reaches a heritage site. So there are possible advantages to using virtual reality technology to create virtual travel,\\u000a savings in

Erik Champion

256

Interfacing with Virtual Worlds  

Microsoft Academic Search

Virtual worlds (often referred to as 3D3C for 3D visualization & navigation and the 3C's of Community, Creation and Commerce) integrate existing and emerging (media) technologies (e.g. instant messaging, video, 3D, VR, AI, chat, voice, etc.) that allow for the support of existing and the development of new kinds of networked services. The emergence of virtual worlds as platforms for

Christian Timmerer; Jean Gelissen; Markus Waltl; Hermann Hellwagner

257

The virtual wind tunnel  

Microsoft Academic Search

The design and implementation of a virtual environment linked to a graphics workstation for the visualization of complex fluid flows are described. The system user wears a stereo head-tracked display, which effectively displays 3-D information, and an instrumented glove to intuitively position flow-visualization tools. The visualization structures and their interfaces in the virtual environment and the implementation hardware and software

S. Bryson; C. Levit

1992-01-01

258

Microscope Imaging Station  

NSDL National Science Digital Library

The Exploratorium in San Francisco continue to break new and intriguing ground with their latest online project, the Microscope Imaging Station. The actual physical Station resides at their museum, and was opened in 2004. Developed to complement this interactive exhibit, this online manifestation of the Station allows visitors to peer into the cells of living organisms such as sea urchins and zebrafish. The sea urchin feature is a real treat, as it is accompanied by a well-written essay on how this spiky creature may help unlock the secrets of genes, reproduction, and cancer. If that wasn't enough, the essay (as with other features on the site) includes a short video clip. The "Gallery" is definitely worth a stop as well. Here, visitors will find a wide range of high-resolution images and movies created with research-grade microscopes. Watching cells move, the fertilization process and the world of mitosis is a rather nice way to spend a few minutes, and visitors will probably want to pass the site along to friends and family.

259

Active Learning: A Small Group Histology Laboratory Exercise in a Whole Class Setting Utilizing Virtual Slides and Peer Education  

ERIC Educational Resources Information Center

|Histology laboratory instruction is moving away from the sole use of the traditional combination of light microscopes and glass slides in favor of virtual microscopy and virtual slides. At the same time, medical curricula are changing so as to reduce scheduled time for basic science instruction as well as focusing on student-centered learning…

Bloodgood, Robert A.

2012-01-01

260

Five years of experience teaching pathology to dental students using the WebMicroscope  

PubMed Central

Background We describe development and evaluation of the user-friendly web based virtual microscopy - WebMicroscope for teaching and learning dental students basic and oral pathology. Traditional students microscopes were replaced by computer workstations. Methods The transition of the basic and oral pathology courses from light to virtual microscopy has been completed gradually over a five-year period. A pilot study was conducted in academic year 2005/2006 to estimate the feasibility of integrating virtual microscopy into a traditional light microscopy-based pathology course. The entire training set of glass slides was subsequently converted to virtual slides and placed on the WebMicroscope server. Giving access to fully digitized slides on the web with a browser and a viewer plug-in, the computer has become a perfect companion of the student. Results The study material consists now of over 400 fully digitized slides which covering 15 entities in basic and systemic pathology and 15 entities in oral pathology. Digitized slides are linked with still macro- and microscopic images, organized with clinical information into virtual cases and supplemented with text files, syllabus, PowerPoint presentations and animations on the web, serving additionally as material for individual studies. After their examinations, the students rated the use of the software, quality of the images, the ease of handling the images, and the effective use of virtual slides during the laboratory practicals. Responses were evaluated on a standardized scale. Because of the positive opinions and support from the students, the satisfaction surveys had shown a progressive improvement over the past 5 years. The WebMicroscope as a didactic tool for laboratory practicals was rated over 8 on a 1-10 scale for basic and systemic pathology and 9/10 for oral pathology especially as various students’ suggestions were implemented. Overall, the quality of the images was rated as very good. Conclusions An overwhelming majority of our students regarded a possibility of using virtual slides at their convenience as highly desirable. Our students and faculty consider the use of the virtual microscope for the study of basic as well as oral pathology as a significant improvement over the light microscope.

2011-01-01

261

Petrology and reservoir paragenesis in the Sussex 'B' sandstone of the upper Cretaceous Cody Shale, House Creek and Porcupine Fields, Powder River Basin, Wyoming  

SciTech Connect

Using petrologic and sedimentologic studies, the paper characterizes the influence of sedimentologic and petrologic variations on reservoir heterogeneity in the Sussex 'B' sandstone in the House Creek and Porcupine fields, Powder River Basin, Wyoming. Effects of authigenic minerals on reservoir properties are described in detail for selected inter-ridge and ridge facies sandstones.

Higley, D.K.

1991-05-03

262

Virtual data in CMS production  

SciTech Connect

Initial applications of the GriPhyN Chimera Virtual Data System have been performed within the context of CMS Production of Monte Carlo Simulated Data. The GriPhyN Chimera system consists of four primary components: (1) a Virtual Data Language, which is used to describe virtual data products, (2) a Virtual Data Catalog, which is used to store virtual data entries, (3) an Abstract Planner, which resolves all dependencies of a particular virtual data product and forms a location and existence independent plan, (4) a Concrete Planner, which maps an abstract, logical plan onto concrete, physical grid resources accounting for staging in/out files and publishing results to a replica location service. A CMS Workflow Planner, MCRunJob, is used to generate virtual data products using the Virtual Data Language. Subsequently, a prototype workflow manager, known as WorkRunner, is used to schedule the instantiation of virtual data products across a grid.

Arbree, A. et al.

2004-08-26

263

The Virtual Slice Setup  

PubMed Central

In an effort to design a simulation environment that is more similar to that of neurophysiology, we introduce a virtual slice setup in the NEURON simulator. The virtual slice setup runs continuously and permits parameter changes including changes to synaptic weights and time course and to intrinsic cell properties. The virtual slice setup permits shocks to be applied at chosen locations and activity to be sampled intra- or extracellularly from chosen locations. By default, a summed population display is shown during a run to indicate the level of activity and no states are saved. Simulations can run for hours of model time, therefore it is not practical to save all of the state variables which in any case are primarily of interest at discrete times when experiments are being run: the simulation can be stopped momentarily at such times to save activity patterns. The virtual slice setup maintains an automated notebook showing shocks and parameter changes as well as user comments. We demonstrate how interaction with a continuously running simulation encourages experimental prototyping and can suggest additional dynamical features such as ligand wash-in and wash-out – alternatives to typical instantaneous parameter change. The virtual slice setup currently uses event-driven cells and runs at approximately 2 minutes/hour on a laptop.

Lytton, William W; Neymotin, Samuel A; Hines, Michael L

2008-01-01

264

Tunable Aqueous Virtual Micropore  

PubMed Central

A charged micro-particle can be trapped in an aqueous environment by forming a narrow virtual pore – a cylindrical space region in which the particle motion in the radial direction is limited by forces emerging from dynamical interactions of the particle charge and dipole moment with external radio-frequency quadrupole electric field. If the particle satisfies the trap stability criteria its mean motion is reduced exponentially with time due to the viscosity of the aqueous environment. Thereafter the long-time motion of particle is subject only to random, Brownian fluctuations, whose magnitude, influenced by the electrophoretic and dielectrophoretic effects and added to the particle size, determines the radius of the virtual pore, which we demonstrate by comparison of computer simulations and experiment. The measured size of the virtual nanopore could be utilized to estimate the charge of a trapped micro-object.

Park, Jae Hyun; Guan, Weihua; Reed, Mark A.; Krstic, Predrag S.

2012-01-01

265

Virtual reality in radiology: virtual intervention  

NASA Astrophysics Data System (ADS)

Intracranial aneurysms are the primary cause of non-traumatic subarachnoid hemorrhage. Morbidity and mortality remain high even with current endovascular intervention techniques. It is presently impossible to identify which aneurysms will grow and rupture, however hemodynamics are thought to play an important role in aneurysm development. With this in mind, we have simulated blood flow in laboratory animals using three dimensional computational fluid dynamics software. The data output from these simulations is three dimensional, complex and transient. Visualization of 3D flow structures with standard 2D display is cumbersome, and may be better performed using a virtual reality system. We are developing a VR-based system for visualization of the computed blood flow and stress fields. This paper presents the progress to date and future plans for our clinical VR-based intervention simulator. The ultimate goal is to develop a software system that will be able to accurately model an aneurysm detected on clinical angiography, visualize this model in virtual reality, predict its future behavior, and give insight into the type of treatment necessary. An associated database will give historical and outcome information on prior aneurysms (including dynamic, structural, and categorical data) that will be matched to any current case, and assist in treatment planning (e.g., natural history vs. treatment risk, surgical vs. endovascular treatment risks, cure prediction, complication rates).

Harreld, Michael R.; Valentino, Daniel J.; Duckwiler, Gary R.; Lufkin, Robert B.; Karplus, Walter

1995-04-01

266

Virtual bronchoscopic navigation.  

PubMed

Virtual bronchoscopic navigation (VBN) is a method for the guidance of a bronchoscope to peripheral lesions using virtual bronchoscopy (VB) images of the bronchial path. Irrespective of the bronchoscopist's skill level, the bronchoscope can be readily guided to the target in a short time. A system to automatically search for the bronchial path to the target has been developed and clinically applied; this system produces VB images of the path to the fourth- to twelfth- (median, sixth-) generation bronchi, and displays the VB images simultaneously with real bronchoscopic images. In this article, the author discusses VBN and the automatic VBN system, reviews the published literature, and describes its usefulness and limitations. PMID:20172434

Asano, Fumihiro

2010-03-01

267

Virtual-Geology.Info  

NSDL National Science Digital Library

At virtual-geology.info, Roger Suthren, a professor at Oxford Brookes University, offers educational materials on geologic phenomena throughout the world. Users can take virtual field trips to study the geology of Scotland, Alaska, and France. In the Regional Geology link, visitors can view wonderful pictures of the volcanoes of Germany, Italy, France, and Greece. Educators can find images of sediments and sedimentary rocks which can be used in a variety of classroom exercises. The website supplies descriptions and additional educational links about sedimentology and environmental geology.

268

Geometry of the Concord, North Carolina, intrusive complex: A synthesis of potential field modeling and petrologic data  

NASA Astrophysics Data System (ADS)

We propose a new model to explain the geometric and petrologic characteristics of a large gabbro-syenite complex in the southern Appalachian Piedmont, based on reinterpretation of available gravity, magnetic, and petrologic data. In our interpretation the complex is composed of vertically stacked, tabular plutons, and the exposed intrusive rocks are underlain by a much larger body, vertically separated by 1-1.5 km. Our model provides a possible explanation for the perplexing absence from the Concord complex of rock types intermediate to syenite and gabbro in the fractionation sequence. Fractionation occurred in the deeper magma chamber, which was episodically tapped to produce syenite and gabbro at higher levels.

Williams, Richard T.; McSween, Harry Y., Jr.

1989-01-01

269

Geology and petrology of the Early Precambrian of the Kodar-Udokan region  

NASA Astrophysics Data System (ADS)

This book presents the results of studies on the geological structure and petrological characteristics of the layered Archean formations of the western part of the Aldan-Stanovoi region (the Kodar-Udokan region). On the basis of these results, it is concluded that the stratified Archean is in fact a polygenic-polychronous laminated megacomplex that was formed in the course of the Archean and the Early Poterozoic periods. This complex includes major crystalline schists, hypersthenic diorites, enderbites, charnockites, granite and plagiogranite gneisses, blastomylonites, and metasomatites. A novel scheme is proposed for the geological partition of the Kodar-Udokan Early Precambrian.

Krivenko, Valentin Afanas'evich; Pinaeva, Tat'iana Aleksandrovna

270

The Case for a Cooperative Studio Classroom: Teaching Petrology in a Different Way  

NSDL National Science Digital Library

NOTE: This file size is large, 16.52 mb. This article describes one educator's attempts to modify his Petrology course, changing the lab-lecture format to one that emphasizes studio and cooperative learning. The goals of the changes are to improve student learning by covering a smaller number of topics in greater depth, deemphasize knowledge-based learning and emphasize development of higher order thinking skills (comprehension, application, analysis, synthesis, evaluation), and help students develop good habits of the mind and fundamental skills useful for lifelong learning. The reformatted course requires that students take more responsibility for their learning.

Perkins, Dexter

2005-01-01

271

A method for fast automated microscope image stitching.  

PubMed

Image stitching is an important technology to produce a panorama or larger image by combining several images with overlapped areas. In many biomedical researches, image stitching is highly desirable to acquire a panoramic image which represents large areas of certain structures or whole sections, while retaining microscopic resolution. In this study, we develop a fast normal light microscope image stitching algorithm based on feature extraction. At first, an algorithm of scale-space reconstruction of speeded-up robust features (SURF) was proposed to extract features from the images to be stitched with a short time and higher repeatability. Then, the histogram equalization (HE) method was employed to preprocess the images to enhance their contrast for extracting more features. Thirdly, the rough overlapping zones of the images preprocessed were calculated by phase correlation, and the improved SURF was used to extract the image features in the rough overlapping areas. Fourthly, the features were corresponded by matching algorithm and the transformation parameters were estimated, then the images were blended seamlessly. Finally, this procedure was applied to stitch normal light microscope images to verify its validity. Our experimental results demonstrate that the improved SURF algorithm is very robust to viewpoint, illumination, blur, rotation and zoom of the images and our method is able to stitch microscope images automatically with high precision and high speed. Also, the method proposed in this paper is applicable to registration and stitching of common images as well as stitching the microscope images in the field of virtual microscope for the purpose of observing, exchanging, saving, and establishing a database of microscope images. PMID:23465523

Yang, Fan; Deng, Zhen-Sheng; Fan, Qiu-Hong

2013-02-14

272

The virtual tricorder: a uniform interface for virtual reality  

Microsoft Academic Search

We describe a new user-interface metaphor for immersive virtual reality — the virtual tricorder. The virtual tricor der visually duplicates a six-degrees-of-freedom input devic e in the virtual environment. Since we map the input device to the tricorder one-to-one at all times, the user identifies the two. Thus, the resulting interface is visual as well as tacti le, multipurpose, and

Matthias M. Wloka; Eliot Greenfield

1995-01-01

273

Video: Focusing a Compound Microscope  

NSDL National Science Digital Library

This video from CUNY Kingsborough Community College describes how to focus a compound microscope. The brief clip, available for viewing on YouTube, would be most useful for students with a basic understanding of the parts of a compound microscope and how to use it. Running time for the video is 0:55.

2013-07-01

274

Teaching Engineering Education Using Virtual Worlds and Virtual Learning Environments  

Microsoft Academic Search

In recent years there has been significant growth in the use of 3D virtual worlds for e-learning and distance education. Virtual learning environments' support teaching and learning in an educational context, offering the functionality to manage the presentation, administration and assessment of coursework. However the presentation layer of virtual learning environment's are highly restrictive offering limited opportunities to create highly

M. J. Callaghan; K. McCusker; J. L. Losada; J. G. Harkin; S. Wilson

2009-01-01

275

Personalized virtual university: Applying personalization in virtual university  

Microsoft Academic Search

A virtual university is an organization, which provides education and learning through web portal over internet and utilizes multimedia technology to provide online classes, course units, and interactive instructor. It also utilizes virtual reality application for support laboratory and tentative activity and at last assessment and certificate issuance. Students, via the internet, can register in virtual university and choose their

Sara Salehi Kukeneh; Asadollah Shahbahrami; Mehregan Mahdavi

2011-01-01

276

Virtual Libraries: Service Realities.  

ERIC Educational Resources Information Center

|This paper discusses client service issues to be considered when transitioning to a virtual library situation. Themes related to the transitional nature of society in the knowledge era are presented, including: paradox and a contradictory nature; blurring of boundaries; networks, systems, and holistic thinking; process/not product, becoming/not…

Novak, Jan

277

Automated virtual colonoscopy  

Microsoft Academic Search

Virtual colonscopy (VC) is a minimally invasive alternative to conventional fiberoptic endoscopy for colorectal cancer screening. The VC technique involves bowel cleansing, gas distension of the colon, spiral computed tomography (CT) scanning of a patient's abdomen and pelvis, and visual analysis of multiplanar 2D and 3D images created from the spiral CT data. Despite the ability of interactive computer graphics

Gordon W. Hunt; Paul F. Hemler; David J. Vining

1997-01-01

278

The Virtual Trinity  

Microsoft Academic Search

This presentation describes new computer techniques to construct realis- tic, three-dimensional models from paintings. Once constructed the 3D environments can be interactively experienced, in a virtual reality fashion. The algorithms described are drawn from the vast Computer Vision literature, notably from the work on Single View Metrology and Three- Dimensional Visual Reconstruction. We show how those algorithms can be easily

Antonio Criminisi

279

Fish tank virtual reality  

Microsoft Academic Search

The defining characteristics of what we call “Fish Tank Virtual Reality” are a stereo image of a three dimensional (3D) scene viewed on a monitor using a perspective projection coupled to the head position of the observer. We discuss some of the relative merits of this mode of viewing as compared to head mounted stereo displays. In addition, we report

Colin Ware; Kevin Arthur; Kellogg S. Booth

1993-01-01

280

Virtual environments in neuroscience  

Microsoft Academic Search

Virtual environments (VEs) let users navigate and interact with computer generated three dimensional (3D) environments in real time, allowing for the control of complex stimuli presentation. These VEs have attracted much attention in medicine, especially in remote or augmented surgery, and surgical training, which are critically dependent on hand-eye coordination. Recently, however, some research projects have begun to test the

Giuseppe Riva

1998-01-01

281

Virtual Synchronous Focus Groups  

Microsoft Academic Search

Background: Traditionally, focus groups have been held as face-to-face meetings with a carefully selected group of participants and a moderator to discuss a topic. With the increasing use of the Internet, message boards, and chat rooms, synchronous and asynchronous virtual focus groups can provide opportunities to collect qualitative information. Objectives: The purpose of this paper is to describe how traditional

Deborah K. Mayer; Stefanie Jeruss; Susan K. Parsons

282

Energy Savers Virtual Home  

NSDL National Science Digital Library

This web-based computer simulation allows the participant to calculate energy savings in various types of virtual residential dwellings by making changes in the appliances, light bulbs, insulation, energy sources, etc. that are used. This is a totally interactive simulation that would be suitable for junior high school through college classes. This simulation also contains links where students can access research information.

2007-09-28

283

The virtual geometry model  

Microsoft Academic Search

The Virtual Geometry Model (VGM) was introduced at CHEP in 2004 [1], where its concept, based on the abstract interfaces to geometry objects, has been presented. Since then, it has undergone a design evolution to pure abstract interfaces, it has been consolidated and completed with more advanced features. Currently it is used in Geant4 VMC for the support of TGeo

I. Hrivnácová; B. Viren

2008-01-01

284

Virre - Virtual Reflecting Tool  

Microsoft Academic Search

Virtual Reflecting Tool (Virre) was developed to support children's reflection process and tutors' data gathering in Kids' Club technology club. Returning back to learning process by reflecting strengthens one's self-guidance and learning. This is realized in Kids' Club and with school students by using Virre. According to Kids' Club tutors' experiences, Virre is the tool that gives motivation to children

P. J. Eronen; I. Jormanainen; M. Virnes

285

A Virtual, Shoestring Vacation  

NSDL National Science Digital Library

If there is a discrepancy between the scope of your imagination and the depth of your bank account, this may be the ideal summer to stretch your horizons by diving into a good book. You can take a virtual vacation to almost any place or time by reading. Y

Texley, Juliana

2009-07-01

286

Virtual Bead Loom  

NSDL National Science Digital Library

This site uses the example of Native American beadwork to demonstrate mathematical concepts (specifically, Cartesian coordinates). The materials include an interactive virtual beadloom with which students can create their own beadwork design. The interdisciplinary lesson may be used in conjunction with instruction on Native American culture and traditions.

2010-12-29

287

Virtual Cardiology Lab  

NSDL National Science Digital Library

The focus of this lab is on heritable diseases of the heart. You are cast here as a virtual intern to accompany a doctor examining three different patients. Each patient is examined, using more than one diagnostic tool, and at each stage, the doctor will invite you to examine the patient yourself and ask for your opinion.

Joseph Perpich, M.D., J.D. (Howard Hughes Medical Institute;)

2008-04-16

288

Acting in virtual reality  

Microsoft Academic Search

Three pairs of professional actors and a director each met in a shared non-immersive virtual reality system over a two-week period to rehearse a short play. The actors and director never met one another physically until a short time before a live rehearsal in front of an audience. The actors were represented by avatars which could be controlled to make

M. Slater; J. Howell; A. Steed; D. P. Pertaub; M. Garau

2000-01-01

289

When Virtual Worlds Expand  

Microsoft Academic Search

The future of a virtual world depends on whether it can grow in subjective size, cultural content, and numbers of human participants. In one form of growth, exemplified by Second Life, the scope of a world increases gradually as new sponsors pay for new territory and inhabitants create content. A very different form of growth is sudden expansion, as when

William Sims Bainbridge

2010-01-01

290

Virtual Roller Coaster  

Microsoft Academic Search

Roller coasters are an attractive, adventurous and exciting form of entertainment. In this paper, we present a virtual roller coaster system, which includes roller coaster simulation software, a motion platform and a motion control unit. We investigate the track structure of the roller coaster and propose a methodology to generate the track automatically. We also simulate the forces exerted on

Zen-chung Shih; Yuh-sen Jaw; Mei-ling Hsu

2000-01-01

291

Virtual Field Trips.  

ERIC Educational Resources Information Center

|Virtual field trips can provide experiences beyond the reach of average K-12 students. Describes multimedia products for school use: Africa Trail, Dinosaur Hunter, Louvre Museum, Magic School Bus Explores the Rainforest, and Up to the Himalayas: Kingdoms in the Clouds and provides book and Internet connections for additional learning,…

Walter, Virginia A.

1997-01-01

292

Virtual Inquiry Experiences  

ERIC Educational Resources Information Center

|Children in classrooms and scientists in laboratories engage in similar activities: they observe, ask questions, and try to explain phenomena. Video conferencing technology can remove the wall between the classroom and the laboratory, bringing children and scientists together. Virtual experiences and field trips can provide many of the benefits…

Harlow, Danielle; Nilsen, Katy

2011-01-01

293

Fitted virtual shadow maps  

Microsoft Academic Search

Too little shadow map resolution and resulting undersampling arti- facts, perspective and projection aliasing, have long been a funda- mental problem of shadowing scenes with shadow mapping. We present a new smart, real-time shadow mapping algorithm that virtually increases the resolution of the shadow map beyond the GPU hardware limit where needed. We first sample the scene from the eye-point

Markus Giegl; Michael Wimmer

2007-01-01

294

Virtual Environments for Health  

NSDL National Science Digital Library

Can we recreate the health benefits of natural environments by visiting virtual ones? Nature reporter Daniel Cressey visits scientists at the University of Birminghamâ who are trying to bring the great outdoors to those who can't get there.

n/a n/a (Scientific American;)

2011-08-11

295

Virtual Museum of Architecture  

NSDL National Science Digital Library

Architect Stephen Lauf created this site, Quondam: A Virtual Museum of Architecture, to combine architecture and computers. Lauf was the first architect in Philadelphia to master computer aided design (CAD) and 3-dimensional computer modeling. Today there are over 30 computer models that mak up the Quondam Web site's core collection.

Lauf, Stephen

296

Virtual keyboard layout optimization  

Microsoft Academic Search

The use of virtual keyboards is becoming ubiquitous with increasing use in mobile devices and touch-screens. Till now the research has mainly focused on developing layouts which support high typing speed, but the error aspect has been largely ignored. This research aims at developing a novel error model which relates accuracy with a given layout using the distance between keys.

Siddharth Jain; Samit Bhattacharya

2010-01-01

297

Literacy in Virtual Worlds  

ERIC Educational Resources Information Center

|Introducing new digital literacies into classroom settings is an important and challenging task, and one that is encouraged by both policy-makers and educators. This paper draws on a case study of a 3D virtual world which aimed to engage and motivate primary school children in an immersive and literacy-rich on-line experience. Planning decisions,…

Merchant, Guy

2009-01-01

298

Virtual Heritage: What Next?  

Microsoft Academic Search

Virtual heritage is the use of computer-based interactive technologies to record, preserve or recreate artifacts, sites and actors of historic, artistic, religious and cultural significance and to deliver the results openly to a global audience in such a way as to provide formative educational experiences through electronic manipulations of time and space. Where do we go from here, and what

Robert J. Stone; Takeo Ojika

2000-01-01

299

Fossil Halls: Virtual Tours  

NSDL National Science Digital Library

Part of a larger online look at the Museum's famed Fossil Halls, this Web site has an overview of the halls' many highlights and four QuickTime virtual tours:Hall of Saurischian Dinosaurs, Hall of Ornithischian Dinosaurs, Hall of Primitive Mammals, and Hall of Advanced Mammals.

300

Virtual First Impressions  

ERIC Educational Resources Information Center

Frequently, a nurse's first and only contact with a graduate school, legislator, public health official, professional organization, or school nursing colleague is made through e-mail. The format, the content, and the appearance of the e-mail create a virtual first impression. Nurses can manage their image and the image of the profession by…

Bergren, Martha Dewey

2005-01-01

301

Virtual anthropology meets biomechanics  

Microsoft Academic Search

A meeting in Vienna in October 2010 brought together researchers using Virtual Anthropology (VA) and Finite Element Analysis (FEA) in order to explore the benefits and problems facing a collaboration between the two fields. FEA is used to test mechanical hypotheses in functional anatomy and VA complements and augments this process by virtue of its tools for acquiring data, for

Gerhard W. Weber; Fred L. Bookstein; David S. Strait

2011-01-01

302

Advanced motorcycle virtual rider  

Microsoft Academic Search

The target of this work is the development of a motorcycle virtual rider model that plans a trajectory and follows it. The reference speed and trajectory are obtained by applying the optimal manoeuvre method (i.e. a nonlinear optimal control technique) to a basic model of the motorcycle. Then, the vehicle control and guidance are obtained using a PID architecture and

R. Lot; M. Massaro; R. Sartori

2008-01-01

303

Virtual reality: An overview  

Microsoft Academic Search

Vqrtual Reality (VR), a technology which began in Air Force and university laboratories more than 20 years ago, is often called Artificial Reality, Cyberspace, or Synthetic Reality. Virtual Reality is a computer-created sensory experience that completely immerses a participant to believe and barely distinguish a \\

Jorge Franchi

1994-01-01

304

Virtual Reality in Chemistry  

Microsoft Academic Search

Thank you for your excellent review. Especially it was a pleasant suprise to see that the article not only mentioned VRML (which about every article within the area does) but also clearly states that “VRML is not Virtual Reality”. I stronly support this statement. VRML is a language which describes (in version 2.0 animated) 3D scenes. With its hyperlink capabilities

Robert Drees

1997-01-01

305

Virtual Campus Tours.  

ERIC Educational Resources Information Center

|College campus "tours" offered online have evolved to include 360-degree views, live video, animation, talking tour guides, interactive maps with photographic links, and detailed information about buildings, departments, and programs. Proponents feel they should enhance, not replace, real tours. The synergy between the virtual tour and other…

Jarrell, Andrea

1999-01-01

306

Virtual Knee Surgery  

NSDL National Science Digital Library

In this online activity, learners assist in performing a virtual total knee replacement surgery. There is a great deal of information about this procedure specifically as well as general surgical information, along with questions the learner must answer (using information given onscreen) before the surgery can proceed.

Edheads; Cosi

2007-01-01

307

Are newsgroups virtual communities?  

Microsoft Academic Search

Online groups have been described as “virtual communities,” although commentators differ on the amount of group feeling that they observe online. This paper reports on a survey that investigated to what extent people who post to 30 widely-varying online groups experience community online. Results show that two-thirds of respondents did indeed perceive a sense of belonging to their group. Beyond

Teresa L. Roberts

1998-01-01

308

Virtual Organization Clusters  

Microsoft Academic Search

Sharing traditional clusters based on multiprogramming systems among different virtual organizations (VOs) can lead to complex situations resulting from the differing software requirements of each VO. This complexity could be eliminated if each cluster computing system supported only a single VO, thereby permitting the VO to customize the operating system and software selection available on its private cluster. While dedicating

Michael A. Murphy; Michael Fenn; Sebastien Goasguen

2009-01-01

309

Virtual Museum Learning  

ERIC Educational Resources Information Center

|This paper examines children's and adults' attitudes to virtual representations of museum objects. Drawing on empirical research data gained from two web-based digital learning environments. The paper explores the characteristics of on-line learning activities that move children from a sense of wonder into meaningful engagement with objects and…

Prosser, Dominic; Eddisford, Susan

2004-01-01

310

Multilingual Virtual City Guides  

Microsoft Academic Search

In this paper the potential of combining low cost systems with technologies for modelling and rendering populated urban scenes and multilingual interactive avatars is presented. As an example, a medieval European city was recreated, such that within this virtual environment, visitors can see for themselves how buildings look and hear from a multilingual interactive guide the history of the place.

Karina Rodriguez Echavarria; Michel Genereux; David B. Arnold; Andrew M. Day; John R. W. Glauert

311

A Virtual Jacob's Ladder  

Microsoft Academic Search

An algorithm for modelling and simulating a virtual Jacob's ladder is presented. Its motion is computed using our phys- ically based simulator Iota. The model used to represent the Jacob's ladder is dynamically restructured during the simu- lation via scripted events, but can also be performed interac- tively by the user. Modelling a Jacob's ladder is achieved by reducing the

Mashhuda Glencross; Alan Murta

312

Definition of Virtual Levels.  

ERIC Educational Resources Information Center

|Presents an examination of graphical displays of solutions to time-dependent Schrodinger equation modeling a laser-excited three-level atom. It suggests that an energy level may be regarded as virtual when it is detuned from resonance by more than two Rabi frequencies. (Author/HM)|

Shore, Bruce W.

1979-01-01

313

Digital phase-shifting atomic force microscope Moiré method  

NASA Astrophysics Data System (ADS)

In this study, the digital atomic force microscope (AFM) Moiré method with phase-shifting technology is established to measure the in-plane displacement and strain fields. The Moiré pattern is generated by the interference between the specimen grating and the virtual reference grating formed by digital image processes. The overlapped image is filtered by two-dimensional wavelet transformation to obtain the clear interference Moiré patterns. The four-step phase-shifting method is realized by translating the phase of the virtual reference grating from 0 to 2?. The principle of the digital AFM Moiré method and the phase-shifting technology are described in detail. Experimental results show that this method is convenient to use and efficient in realizing the microscale measurement.

Liu, Chia-Ming; Chen, Lien-Wen

2005-04-01

314

A Virtual Assembly Design Environment  

Microsoft Academic Search

The Virtual Assembly Design Environment (VADE) is a Virtual Reality (VR)-based engineering application that allows engineers to evaluate, analyze, and plan the assembly of mechanical systems. This system focuses on utilizing an immersive, virtual environment tightly coupled with commercial computer aided design (CAD) systems. Salient features of VADE include: 1) data integration (two-way) with a parametric CAD system, 2) realistic

Sankar Jayaram; Yong Wang; Uma Jayaram; Kevin W. Lyons; Peter Hart

1999-01-01

315

Technology Counts 2012: Virtual Shift  

ERIC Educational Resources Information Center

|Virtual education is moving into that intersection where rising popularity meets calls for greater accountability. How the virtual education movement responds to those calls will have a significant impact on how it evolves in K-12 over the next five to 10 years. This report tackles this shift in the virtual education landscape. It examines the…

Education Week, 2012

2012-01-01

316

GENERATING VIRTUAL ARCHITECTURE WITH STYLE  

Microsoft Academic Search

Virtual architecture is a networked spatial environment designed using the metaphor of physical architecture 1 , from which virtual architecture inherits many visual and spatial characteristics. However, in order to further explore its potential, virtual architecture need to go beyond its physical metaphor to develop its own theories and styles. One important step of this process is to establish a

Ning Gu; Mary Lou Maher

317

Constructing Meaning with Virtual Reality.  

ERIC Educational Resources Information Center

|Presents a constructivist rationale for introducing virtual reality in language learning and teaching and describes various virtual reality environments that are available. Ways of implementing constuctivist learning through virtual reality are suggested as well as basic guidelines for successful implementation in the classroom. (Author/VWL)|

Iaonnou-Georgiou, Sophie

2002-01-01

318

Performance Optimization of Virtual Keyboards  

Microsoft Academic Search

Text entry has been a bottleneck of nontraditional computing devices. One of the promising methods is the virtual keyboard for touch screens. Correcting previous estimates on virtual keyboard efficiency in the literature, we estimated the potential performance of the existing QWERTY, FITALY, and OPTI de- signs of virtual keyboards to be in the neighborhood of 28, 36, and 38 words

Shumin Zhai; Michael Hunter; Barton A. Smith

2002-01-01

319

Technology Counts 2012: Virtual Shift  

ERIC Educational Resources Information Center

Virtual education is moving into that intersection where rising popularity meets calls for greater accountability. How the virtual education movement responds to those calls will have a significant impact on how it evolves in K-12 over the next five to 10 years. This report tackles this shift in the virtual education landscape. It examines the…

Education Week, 2012

2012-01-01

320

Virtual Schools: Charting New Frontiers.  

ERIC Educational Resources Information Center

|Discusses virtual schools that have a World Wide Web presence and use the Web and the Internet, provides an evaluation methodology, and describes three specific virtual schools: The Virtual High School, a collaborative of high schools from across the United States; The Virginia Internet High School; and Cyberschool, in Eugene, Oregon. (LRW)|

Rutkowski, Kathleen

1999-01-01

321

Contextualising Virtuality: Polychronicity and Multipresence  

Microsoft Academic Search

Virtuality implies fundamental transformations of temporal and spatial aspects of interaction and work. In this paper, we suggest that we can better conceptualise the notion of virtuality through examining it in terms of polychronicity and multipresence. These allow us to examine the underlying nature of what it means to be virtual, in a variety of contexts. One of these contexts

Heejin Lee; Mark Perry

322

Virtual Worlds in Computing Education  

ERIC Educational Resources Information Center

|This article reports on the use of a virtual world ("Second Life") in computing education, and identifies the precursors of current virtual world systems. The article reviews the potential for virtual worlds as tools in computing education. It describes two areas where "Second Life" has been used in computing education: as a development…

Crellin, Jonathan; Duke-Williams, Emma; Chandler, Jane; Collinson, Timothy

2009-01-01

323

Transition of a dental histology course from light to virtual microscopy.  

PubMed

The transition of the dental histology course at the University of Texas Health Science Center at San Antonio Dental School was completed gradually over a five-year period. A pilot project was initially conducted to study the feasibility of integrating virtual microscopy into a traditional light microscopic lecture and laboratory course. Because of the difficulty of procuring quality calcified and decalcified sections of teeth, slides from the student loan collection in the oral histology block of the course were outsourced for conversion to digital images and placed on DVDs along with a slide viewer. The slide viewer mimicked the light microscope, allowing horizontal and vertical movement and changing of magnification, and, in addition, a feature to capture static images. In a survey, students rated the ease of use of the software, quality of the images, maneuverability of the images, and questions regarding use of the software, effective use of laboratory, and faculty time. Because of the positive support from the students, our entire student loan collection of 153 glass slides was subsequently converted to virtual images and distributed on an Apricorn pocket external hard drive. Students were asked to assess the virtual microscope over a four-year period. As a result of the surveys, light microscopes have been totally eliminated, and microscope exams have been replaced with project slide examinations. In the future, we plan to expand our virtual slides and incorporate computer testing. PMID:19805786

Weaker, Frank J; Herbert, Damon C

2009-10-01

324

Geochemical And Petrological Investigations Of The Representative Cretaceous Bentonite Beds, Wyoming : Tectonic Implications  

NASA Astrophysics Data System (ADS)

Representative bentonite samples were collected from the exposed Cretaceous siliciclastics in Bighorn Basin, north-central Wyoming. Bentonite beds constitute a significant stratigraphic importance with respect to local and regional correlation tool and are associated with the Thermopolis Shale (Lower Cretaceous), Mowry Shale (Lower Cretaceous), and Frontier Formation (Upper Cretaceous). These beds range in thickness from few inches to ten feet and are interbedded with thick cross-bedded sandstone, pebbly sandstone, polymictic conglomerate, siliceous-rippled shale, and lignitic shale. Preliminary petrological and geochemical investigations were carried out to establish a distinctive geochemical signature for each bed. Emphasis was given on the overall distribution of the immobile traces, high refractory elements, and ultrastable heavy mineral components among the selective bentonite beds. The outcome of petrological, bulk, and trace element studies involving multiple bentonite beds indicated a subtle difference in terms of abundance of trace-element and detrital components among the studied samples and can be attributed to the source region characteristics, distinctive diagenetic pathways, and depositional setting. Furthermore, geochemical analyses involving multi-element plots suggest to an evolving source terrain located in close proximity to the bentonite depositional basin.

Khandaker, N. I.

2004-12-01

325

Interactive computer programs for petrologic modeling with extended Q-mode factor analysis  

USGS Publications Warehouse

An extended form of Q-mode factor analysis may be used if the row-sums of the data matrix are constant and can be helpful especially in developing and testing petrologic-mixing models for igneous systems. The first step is to represent the sample compositions as unit vectors in M-dimensional space and then to project them into space of fewer dimensions (m) as determined to be appropriate from a factor-variance diagram. Compositions thought to be those of possible end-members in the petrologic system then are represented as vectors in the M-dimensional space and projected into the same space as the sample vectors. If these vectors remain close to unity in length after projection, the corresponding compositions can serve as end-member compositions for the model. After m suitable end-member compositions have been identified, each sample composition is expressed as a mixture of the end-members by computation of the composition loadings. The interactive computer programs presented are useful in these procedures because of the trial-and-error nature of the modeling procedures. ?? 1976.

Miesch, A. T.

1976-01-01

326

Mantle temperature variations beneath back-arc spreading centers inferred from seismology, petrology, and bathymetry  

NASA Astrophysics Data System (ADS)

Variations in seismological structure, major element composition, and axial depth between different back-arc spreading centers provide constraints on physical conditions associated with back-arc melt production. We invert vertical and transverse seismograms from several representative paths traversing the Mariana, Lau, North Fiji, and East Scotia back-arc basins. Seismic velocity varies substantially at depths of 40-100 km, with differences of up to 7% between the slowest (Lau) and the fastest (Mariana) structures. These mantle seismological structures correlate with major element systematics and the elevations of the ridge axes, consistent with differences in average upper mantle temperatures. In contrast to the temperature correlation, mantle seismic structure shows no apparent correlation with petrologically inferred water content. Petrological indicators suggest a ˜ 100 °C range in mantle potential temperature, consistent with the seismic velocity variations, assuming experimentally determined temperature derivatives. The temperature variations, however, must extend throughout the upper ˜ 200 km of the mantle wedge to produce the observed ridge elevation differences. Fast slab rollback and the influx of hot Samoan mantle may contribute to high temperatures in the Lau Basin.

Wiens, Douglas A.; Kelley, Katherine A.; Plank, Terry

2006-08-01

327

Microscopic approach to entropy production  

NASA Astrophysics Data System (ADS)

It is a great challenge of nonequilibrium statistical mechanics to calculate entropy production within a microscopic theory. In the framework of linear irreversible thermodynamics, we combine the Mori-Zwanzig-Forster projection operator technique with the first and second law of thermodynamics to obtain microscopic expressions for the entropy production as well as for the transport equations of the entropy density and its time correlation function. We further present a microscopic derivation of a dissipation functional from which the dissipative dynamics of an extended dynamical density functional theory can be obtained in a formally elegant way.

Wittkowski, Raphael; Löwen, Hartmut; Brand, Helmut R.

2013-09-01

328

TECHNOLOGY APPLICATION: VIRTUAL FIELD TRIPS  

NSDL National Science Digital Library

This webquest will assist in furthering your understanding of the ins and outs of virtual fieldtrips, provide links to ready-made virtual fieldtrips, and provide a link so you can create your own virtual field trip. Virtual field trips have become increasingly popular with the extensive use of the world wide web. One reason for this is probably the ease with which this technology can be delivered. All that is required is a computer with internet access. Occasionally a virtual field trip will require some plug-ins ...

Hoskins, Mr.

2006-03-23

329

Synergies of virtual screening approaches.  

PubMed

Virtual screening is a knowledge driven approach. Therefore, synergies between different virtual screening methods using information about the drug target as well as about known ligands in combination promise the best results. Finding novel active scaffolds is often a more important success criterion than hit rates of virtual screens. Novelty should also be considered in balance with often weaker activities of virtual screening hits. Virtual screening is most effective if performed in iterations following up on weak primary hits of interest through testing of structural analogs and additional synthesis of compounds. PMID:18691150

Muegge, Ingo

2008-08-01

330

Cyclicity in layered intrusions as revealed by near-continuous geophysical and petrologic measurements in the Bushveld Complex, South Africa  

Microsoft Academic Search

We present a large database of geophysical and petrological measurements for a ˜3000 m borehole through the entire Upper Zone (UZ) and most of the Main Zone (MZ) of the Bushveld Complex (Northern Lobe), South Africa. Magnetic susceptibility readings were taken every 2 cm (n = 109,360), and densities were measured about every 1.7 m (n = 2252). Petrographic data

L. D. Ashwal; S. J. Webb; M. W. Knoper

2003-01-01

331

Crystal chemistry, and thermodynamic and kinetic properties of calcite, dolomite, apatite, and biogenic silica: applications to petrologic problems  

Microsoft Academic Search

Sedimentary minerals are generally metastable phases that, given time and changing environmental conditions, recrystallize to more stable phases. The actual pathway of stabilization is governed by a host of kinetic factors. Unfortunately, much of the theoretical and experimental work on thermodynamic and kinetic behavior of sedimentary minerals either has not reached field practitioners in sedimentary petrology, or has been conducted

Jane S. Tribble; Rolf S. Arvidson; Fred T. Mackenzie

1995-01-01

332

Depth variation of seismic anisotropy and petrology in central European lithosphere: A tectonothermal synthesis from spinel lherzolite  

Microsoft Academic Search

Spinel lherzolite xenoliths from the Neogene Kozákov volcano in central Europe, yielding temperatures from 680°C to 1065°C and estimated to originate from depths of 32 to 70 km, provide an exceptionally continuous record of the depth variation in seismic and petrological properties of subcontinental lithospheric mantle. Extraction depths of the xenoliths and thermal history and rheological properties of the mantle

N. I. Christensen; H. F. Wang; E. Jelínek

2001-01-01

333

Thermal modeling of the southern Alaska subduction zone: Insight into the petrology of the subducting slab and overlying mantle wedge  

SciTech Connect

This report discusses a two-dimensional thermal model of the southern Alaska subduction zone. This model allows specfic predictions to be made about the pressure-temperature conditions and mineralogy of the subducting oceanic crust and the mantle wedge and assess different petrologic models for the generation of Alaskan arc magmas.

Ponko, S.C.; Peacock, S.M. [Arizona State Univ., Tempe, AZ (United States)

1995-11-10

334

Amino acid composition, petrology, geochemistry, 14C terrestrial age and oxygen isotopes of the Shisr 033 CR chondrite  

Microsoft Academic Search

We have analyzed Shisr 033, a CR chondrite from the Omani desert, using several different analytical techniques designed to study the degree of terrestrial alteration of this meteorite and also its petrologic classification. Bulk chemical analyses (including organic carbon and mean total H2O content) are consistent with a CR classification. Additionally, oxygen isotope analysis on a bulk sample indicates that

Z. Martins; B. A. Hofmann; E. Gnos; R. C. Greenwood; A. Verchovsky; I. A. Franchi; A. J. T. Jull; O. Botta; D. P. Glavin; J. P. Dworkin; P. Ehrenfreund

2007-01-01

335

21. THE PETROLOGY, GEOCHEMISTRY, AND MINERALOGY OF NORTH ATLANTIC BASALTS: A DISCUSSION BASED ON IPOD LEG 49  

Microsoft Academic Search

Whole-rock geochemical data were obtained for 178 samples selected hm the petrologically freshest parts of most of the flow units recovered kom the nine holes. These data include 170 major element analyses (XRF) and 174 trace-element analyses (XRF and INAA). We include representative microprobe analyses of the pnmary minerals and fresh basaltic glasses (where present) in 40 selected samples. We

D. A. Wood; H. Bo; J. L. Joron; M. Treuil; H. Bizouard; C. J. Hawkesworth; J. C. Roddick

336

The Athena Microscopic Imager on the Mars Exploration Rovers  

NASA Astrophysics Data System (ADS)

The Athena science payload on the Mars Exploration Rovers (MER) includes the Microscopic Imager (MI). The MI is a fixed-focus camera mounted on the end of the Instrument Deployment Device (IDD). The MI was designed to acquire images at a spatial resolution of 30 microns/pixel over a broad spectral range (400-700 nm). Technically speaking, the ''microscopic'' imager is not a microscope: it has a fixed magnification of 0.4, and is intended to produce images that simulate a geologist's view when using a common hand lens. The MI uses the same electronics design as the other MER cameras, but has optics that yield a field of view of 31 x 31 mm. The MI will acquire images using only solar or skylight illumination of the target surface. A contact sensor will be used to place the MI slightly closer to the target surface than its best focus distance (about 66 mm), allowing concave surfaces to be imaged in good focus. Because the MI has a relatively small depth of field (+/- 3 mm), a single MI image of a rough surface will contain both focused and unfocused areas. Coarse (~2 mm precision) focusing will be achieved by moving the IDD away from a target after the contact sensor is activated. Multiple images taken at various distances will be acquired to ensure good focus on all parts of rough surfaces. By combining a set of images acquired in this way, a completely focused image will be assembled. The MI optics will be protected from the martian environment by a dust cover. The dust cover includes a polycarbonate window that is tinted yellow to restrict the spectral bandpass to 500-700 nm and allow color information to be obtained by taking images with the dust cover open and closed. The MI will be used to image the same materials measured by other Athena instruments, as well as targets of opportunity (before rover traverses). The resulting images will be used to place other instrumental data in context and to aid in the petrologic interpretation of rocks and soils on Mars.

Herkenhoff, K. E.; Squyres, S. W.; Bell, J. F.; Maki, J. N.; Schwochert, M. A.

2002-12-01

337

(Center of excellence: Microlaser microscope)  

SciTech Connect

This Center-of-Excellence grant has two components: development of an imaging system based on microlaser arrays forms a central project among a group of laser diagnostic and therapeutic efforts primarily funded outside the grant. In these first 8 months we have set up the Microlaser Microscope using small microlaser arrays. We have emphasized the basics of microlaser handling and electronic addressing and the optics of the microscope. Details of electronics and optics given here will be used in the larger arrays which should be available soon. After a description of the central Microlaser Microscope project, we touch briefly on the other projects of the Center, which have been outstandingly fruitful this year. Publications are necessarily concerned with the smaller projects, since the Microlaser Microscope is in its early stages.

Webb, R.H.

1992-01-01

338

Magnetic Resonance Force Microscope Development  

SciTech Connect

Our objectives were to develop the Magnetic Resonance Force Microscope (MRFM) into an instrument capable of scientific studies of buried structures in technologically and scientifically important electronic materials such as magnetic multilayer materials. This work resulted in the successful demonstration of MRFM-detected ferromagnetic resonance (FMR) as a microscopic characterization tool for thin magnetic films. Strong FMR spectra obtained from microscopic Co thin films (500 and 1000 angstroms thick and 40 x 200 microns in lateral extent) allowed us to observe variations in sample inhomogeneity and magnetic anisotropy field. We demonstrated lateral imaging in microscopic FMR for the first time using a novel approach employing a spatially selective local field generated by a small magnetically polarized spherical crystallite of yttrium iron garnet. These successful applications of the MRFM in materials studies provided the basis for our successful proposal to DOE/BES to employ the MRF M in studies of buried interfaces in magnetic materials.

Hammel, P.C.; Zhang, Z.; Suh, B.J.; Roukes, M.L.; Midzor, M.; Wigen, P.E.; Childress, J.R.

1999-06-03

339

Circular Extinction Contrast Imaging Microscope.  

National Technical Information Service (NTIS)

Systems and methods for producing circular extinction (CE) contrast images of anisotropic samples. Microscope systems for determining circular extinction (CE), the differential transmission of left and right circularly polarized light resulting from circu...

B. Kahr W. Kaminsky

2004-01-01

340

California Virtual Campus  

NSDL National Science Digital Library

California Virtual Campus is essentially a catalog of every virtual or technology-mediated distance education course or program offered by participating California colleges and universities. Users can search for a particular course or find information about pursuing a complete program of study from certificate level to PhD. The site summarizes important information about each course or program, such as in-state and out-of-state fees, email contacts, and registration details. For example, a search returned a list of 30 art-related course offerings at about 20 different institutions. By clicking on a title, "Visionary Artists: A Brief History of Multimedia," I found I could take this course, offered by San Francisco State University, by registering and paying a fee of $5.

341

UVA Virtual Lab  

NSDL National Science Digital Library

The Virtual Lab, developed by the University of Virginia, provides visual representation of the scientific principles we encounter daily. Mini labs allow visitors to learn about different properties of physics, chemistry and technology. The Electricity and Magnetism Lab introduces concepts like basic charge attraction and repulsion and magnetic induction. Units on semiconductors, circuits, nanoscience and scientific instruments are also available in the Virtual Lab. The UVA is also beginning to convert presentations from the website into narrated Podcasts, which are available from the homepage. This is a great resource to incorporate into the classroom as the labs are very informative, easy to follow, and would aid students in visualizing the scientific concepts they are learning.

2007-04-17

342

Virtual Yeast Cell  

NSDL National Science Digital Library

Learning about the various parts of a cell can be tricky business, but this virtual yeast cell offered by The University of Nottingham will come in handy for biology students and science instructors. This learning resource was created to help students in the brewing science program learn about yeast cytology, though just about anyone with an interest in cells will learn something from visiting the site. After entering the interactive cell, visitors can click on different parts of the cell (such as the cytoplasm or the nucleus) in order to learn more about the importance of each one. Visitors should remember that they can also download the virtual yeast cell and use it in the classroom or just with a group of friends.

343

Virtual Yeast Cell  

NSDL National Science Digital Library

Learning about the various parts of a cell can be tricky business, but this virtual yeast cell offered by The University of Nottingham will come in handy for biology students and science instructors. This learning resource was created to help students in the brewing science program learn about yeast cytology, though just about anyone with an interest in cells will learn something from visiting the site. After entering the interactive cell, visitors can click on different parts of the cell (such as the cytoplasm or the nucleus) in order to learn more about the importance of each one. Visitors should remember that they can also download the virtual yeast cell and use it in the classroom or just with a group of friends.

2008-02-28

344

The Virtual Bookshelf  

NSDL National Science Digital Library

Island Multimedia has created a virtual library of full-text electronic books, many of which are geared toward a young adult audience. The current selection of 18 titles includes works by American authors Willa Cather, Nathaniel Hawthorne, Edgar Allan Poe, and Mark Twain. The difference between this site and those of other electronic publishers is that here Internauts can register for their own free "virtual bookshelf." With registration comes the ability to highlight favorite passages to return to later, as well as the ability to state preferences for font and background color of the books on your personal bookshelf. Unregistered visitors can click on any "Add to Shelf" box to bring up a registration form. The site has also provided a toll-free phone number for a help line.

1997-01-01

345

Theft of Virtual Property — Towards Security Requirements for Virtual Worlds  

NASA Astrophysics Data System (ADS)

The article is focused to introduce the topic of information technology security for Virtual Worlds to a security experts’ audience. Virtual Worlds are Web 2.0 applications where the users cruise through the world with their individually shaped avatars to find either amusement, challenges or the next best business deal. People do invest a lot of time but beyond they invest in buying virtual assets like fantasy witcheries, wepaons, armour, houses, clothes,...etc with the power of real world money. Although it is called “virtual” (which is often put on the same level as “not existent”) there is a real value behind it. In November 2007 dutch police arrested a seventeen years old teenager who was suspicted to have stolen virtual items in a Virtual World called Habbo Hotel [Reuters07]. In order to successfully provide security mechanisms into Virtual Worlds it is necessarry to fully understand the domain for which the security mechansims are defined. As Virtual Worlds must be clasified into the domain of Social Software the article starts with an overview of how to understand Web 2.0 and gives a short introduction to Virtual Worlds. The article then provides a consideration of assets of Virtual Worlds participants, describes how these assets can be threatened and gives an overview of appopriate security requirements and completes with an outlook of possible countermeasures.

Beyer, Anja

346

Functionally based virtual embossing  

Microsoft Academic Search

  Embossing is the art of decorating metals in relief from the reverse side. This article describes how virtual embossing can\\u000a be done using a functionally based representation of the metal plate and the tools. The program is implemented as an interactive\\u000a shape modeler where a functional model of the metal plate is subsequently modified with offset and set-theoretic operations.\\u000a For

Alexei Sourin

2001-01-01

347

Conceptualizing Virtual Collaborative Work  

Microsoft Academic Search

The purpose of this paper is to define the phenomena associated with virtual collaborative work from both a cognitive and\\u000a social cognitive perspective. The authors put forth an approach that assumes all people are natural sense-makers, sense-givers\\u000a and organizers. The authors posit that the collaborative work we observe within both informal (ad hoc teams or communities)\\u000a and formal (organizational) environments

Michael A. D'eredita; Michael Sanford Nilan

2007-01-01

348

When Virtual Worlds Expand  

Microsoft Academic Search

\\u000a The future of a virtual world depends on whether it can grow in subjective size, cultural content, and numbers of human participants.\\u000a In one form of growth, exemplified by Second Life, the scope of a world increases gradually as new sponsors pay for new territory and inhabitants create content. A very different\\u000a form of growth is sudden expansion, as when

William Sims Bainbridge

349

The virtual design team  

Microsoft Academic Search

The long range goal of the "Virtual Design Team" (VDT) research program is to develop computationaltools to analyze decision making and communication behavior and thereby to support true organizational(re)engineering. This article introduces the underlying theory, the implementation of the theory as acomputational model, and results from industrial test cases. Organization theory traditionally describesorganizations only at an aggregate-level, describing and predicting

John C. Kunz; Tore R. Christiansen; Geoff P. Cohen; Yan Jin; Raymond E. Levitt

1998-01-01

350

A Virtual, Shoestring Vacation  

ERIC Educational Resources Information Center

|If there is a discrepancy between the scope of your imagination and the depth of your bank account, this may be the ideal summer to stretch your horizons by diving into a good book. You can take a virtual vacation to almost any place or time by reading. You will not need to fill your gas tank or empty your pocketbook. Reading has a small carbon…

Texley, Juliana

2009-01-01

351

Virtual environment technology  

Microsoft Academic Search

Since the late 1960s and early 1970s researchers have been building novel display devices-- including head-mounted displays (HMDs)--and a variety of manual input devices, including force input and output. With the advent of powerful graphic workstations, and relatively inexpensive HMDs and glove-like input devices, however, interest in 'virtual environments' seems to be rising exponentially. In this paper the key components

David L. Zeltzer

1991-01-01

352

Virtual Biology Labs  

NSDL National Science Digital Library

This Rutgers University Web site contains a set of online biology labs each so detailed and comprehensive, they could nearly replace the real thing. Each virtual lab contains pages and pages of background information and procedures, helpful images and diagrams, online exercises, and more. Seven labs are currently available: Cell Structure, Cell Reproduction, Protists, Plant Evolution, Angiosperm Reproduction, Transport Systems in Plants, and Chromosome Structure and Meiosis.

353

Virtual Communities of Practice  

Microsoft Academic Search

There is an increased interest in the use of virtual technology and distance courses in professional education. Teacher education\\u000a is no exception, particularly with pressures to maintain professional standards. The problem of course is that the conception\\u000a of what it is to be a professional teacher influences the development of such courses and programs. If teacher is characterized\\u000a as discerner,

Kathryn Hibbert; Sharon Rich

354

Virtual classroom pedagogy  

Microsoft Academic Search

For lecturers who are used to presenting face-to-face, facilitating online classes through a virtual classroom interface proposes several new challenges. At the same time the affordances of the media offer many opportunities to improve the quality of students' learning. This paper outlines the pedagogical lessons derived from convening a first year introductory programming unit through a series of twelve, two-hour

Matt Bower

2006-01-01

355

On thermodynamic and microscopic reversibility  

SciTech Connect

The word 'reversible' has two (apparently) distinct applications in statistical thermodynamics. A thermodynamically reversible process indicates an experimental protocol for which the entropy change is zero, whereas the principle of microscopic reversibility asserts that the probability of any trajectory of a system through phase space equals that of the time reversed trajectory. However, these two terms are actually synonymous: a thermodynamically reversible process is microscopically reversible, and vice versa.

Crooks, Gavin E.

2011-07-12

356

SQUID–BASED MAGNETIC MICROSCOPE  

Microsoft Academic Search

Two types of scanning magnetic microscopes (MM) are known nowadays: force magnetic microscopes (FMM) and non-force MM (NFMM)\\u000a ones. The second type of MM can be used to measure a distribution of the vertical component of magnetic fields over surfaces,\\u000a including cases such as in a cavity of solid test objects (TO) and inside a liquid TO, without external forces

S. Bondarenko; N. Nakagawa

357

HIGH TEMPERATURE MICROSCOPE AND FURNACE  

DOEpatents

A high-temperature microscope is offered. It has a reflecting optic situated above a molten specimen in a furnace and reflecting the image of the same downward through an inert optic member in the floor of the furnace, a plurality of spaced reflecting plane mirrors defining a reflecting path around the furnace, a standard microscope supported in the path of and forming the end terminus of the light path.

Olson, D.M.

1961-01-31

358

The Berkeley Scanning Electron Microscope-I.  

National Technical Information Service (NTIS)

This report describes the Berkeley Scanning Electron Microscope-I. The principles of operation of a scanning electron microscope and the design criteria for this particular microscope are stated in the introduction. The vacuum system, the electron-optics,...

T. E. Everhart R. F. W. Pease S. R. Pedersen

1966-01-01

359

Gallery of Virtual Topography  

NSDL National Science Digital Library

The Gallery of Virtual Topography features virtual depictions of topography, including 3D perspectives and QuickTime Virtual Reality (QTVR) movies, created from Digital Elevation Models (DEM's). The site showcases QTVR object movies where the user can spin a 3D terrain to view it from different perspectives. It also includes static 3D-perspective images (JPEG files) of the 3D terrains for those users with slower Internet connections. Some movies and images depict only the form of the landscape, but in others topographic contours are draped over the landscape to better illustrate how contours portray different types of topography (cliffs versus badlands, for example). Some animations illustrate the significance of contours, by allowing the user to progressively fill the landscape up with water to see the water interact with different topographic features. The site also contains a topographic contour map for each 3D terrain, so that instructors can develop student exercises, such as locating points on a map and constructing topographic profiles. Some QTVR movies contain numbered topographic features just for this purpose.

Reynolds, Stephen

360

High efficiency virtual impactor  

DOEpatents

Environmental monitoring of atmospheric air is facilitated by a single stage virtual impactor (11) for separating an inlet flow (Q.sub.O) having particulate contaminants into a coarse particle flow (Q.sub.1) and a fine particle flow (Q.sub.2) to enable collection of such particles on different filters (19a, 19b) for separate analysis. An inlet particle acceleration nozzle (28) and coarse particle collection probe member (37) having a virtual impaction opening (41) are aligned along a single axis (13) and spaced apart to define a flow separation region (14) at which the fine particle flow (Q.sub.2) is drawn radially outward into a chamber (21) while the coarse particle flow (Q.sub.1) enters the virtual impaction opening (41). Symmetrical outlet means (47) for the chamber (21) provide flow symmetry at the separation region (14) to assure precise separation of particles about a cutpoint size and to minimize losses by wall impaction and gravitational settling. Impulse defocusing means (42) in the probe member (37) provides uniform coarse particle deposition on the filter (19a) to aid analysis. Particle losses of less than 1% for particles in the 0 to 20 micron range may be realized.

Loo, Billy W. (Oakland, CA)

1981-01-01

361

Medicine in virtual environments.  

PubMed

Virtual Environments allow a human to interact with a (computer) system in such a way that a high level of presence in a computer-synthesised world is experienced. In principle, all human senses are involved with the interaction. Many applications may benefit from this type of human-machine interfacing, however, few have emerged so far for medicine. In this paper we elaborate on some realistic potential applications of Virtual Environment technology in the field of medicine. These applications can be found in education/training, therapy, surgery, rehabilitation, diagnosis, telemedicine and biomechanics. The value to be added to these applications by VE technology lies in the fact that patient data or patient models may be moderated to the physician in a more intuitive and natural manner. Despite these potentials, the short-term feasibility of these applications can be put into question for various reasons. Firstly, the current generation of display devices have a resolution that may show to be too low to achieve a sufficiently high degree of realism for medical applications. Secondly, there are no commercially-available actuators for tactile and force feedback which the physician desperately need for the simulation of the contact with the (virtual) patient. Thirdly, the enormous computing power required for these applications (still) needs a considerable investment. With these limitations in mind, we believe that we are at the cradle of a whole new generation of VE applications in medicine. PMID:8574765

Dumay, A C

1995-10-01

362

Virtual environment technology  

NASA Astrophysics Data System (ADS)

Since the late 1960s and early 1970s researchers have been building novel display devices-- including head-mounted displays (HMDs)--and a variety of manual input devices, including force input and output. With the advent of powerful graphic workstations, and relatively inexpensive HMDs and glove-like input devices, however, interest in 'virtual environments' seems to be rising exponentially. In this paper the key components of a virtual environment-- autonomy, interaction and presence--are described. Autonomy is a qualitative measure of the capability of computational models to act and react to simulated events and stimuli. Interaction measures the degree of access to model parameters at runtime, ranging from batch processing with no interaction to comprehensive, real-time access to all model parameters. Presence is a rough measure of the number and fidelity of available sensory input and output channels. Work on representing and controlling synthetic autonomous agents for virtual environments will be briefly reviewed. Videotaped examples will be shown.

Zeltzer, David L.

1991-06-01

363

Single-wavelength STED microscope  

NASA Astrophysics Data System (ADS)

The zero-point STED microscope (US Pat. 5,866,911)1 was the first far-field microscope to overcome the diffraction limit, but optimally it requires two expensive synchronized short-pulsed lasers. Replacing the synchronized pulsed lasers with CW lasers had been proposed to reduce costs1, but this seriously reduced resolution compared to a similarly powered pulsed STED microscope. A recent theoretical and experimental study (Nat. Methods 4, 915 (2007))3 argued that CW STED has better resolution than previously believed, but there appear to be flaws in the theory sufficient to raise questions about its reported experimental confirmation. We describe an alternative approach to reducing cost of the STED microscope while preserving resolution. A portion of the beam from a femtosecond pulsed laser of a wavelength able to excite fluorescence by multiphoton absorption, is passed through a long optical fiber to stretch the pulses to reduce their peak power so they can no longer excite but can quench by stimulated emission. The stretched pulses are shaped into a doughnut profile and then recombined with the first beam for interaction with the specimen. With suitable fluorophores, this instrument should be able to match the resolution performance of the pulsed laser STED microscope using separate lasers. Particularly when added to an existing multiphoton microscope, such performance should be achievable at extremely low added cost.

Baer, Stephen C.

2011-02-01

364

Petrological studies on the mantle peridotites recovered from the ocean floor in the western Pacific  

NASA Astrophysics Data System (ADS)

Geological and geophysical models for the various oceanic crusts (or lithosphere) have been proposed on the basis of the combined studies between seismic observation for the oceanic crusts and petrological models of the onland ophiolites, which have been assumed as fossil of oceanic crusts. It is very important to collect basement rocks constituting various oceanic crusts and to characterize those petrological features. Ocean floor is commonly covered by effusive volcanic rocks, however occasionally hypabyssal and plutonic rocks are observed among the unique geological environments in the Western Pacific as partly shown in the followings. VOLCANIC DIATREME(?): Very unique volcanic knolls have been recently discovered by N. Hirano at the typical oceanic crust in the Northwestern Pacific, off Tohoku of Northeastern Japan. The constituting rocks for the main volcanic edifice are porous alkaline lavas with 1-5Ma age containing abundant lithic fragments including gabbros as well as mantle peridotites. They are assumed as a volcanic diatreme induced in the Cretaceous oceanic lithosphere . Geological and petrological analyses on those volcano and volcanic rocks can make clear the geological cross (or columnar) section of the typical oceanic lithosphere including crust as well as upper mantle down to 100 km deep asthenospheric mantle. PARECE VERA BASIN: The Parece Vela Basin (PVB) is an extinct backarc basin in the Philippine Sea. The NNE extending escarpments and depressions (maximum depth 7500 m) are fossil fracture zones and extinct segmented spreading axes (first-order segments), respectively. Oceanic core complexes (OCCs), or megamullions, develop at each first-order segment. Recently discovered OCCs at slow-spreading ridges have been interpreted as exhumed footwalls of oceanic detachment faults in magma-starved ridge environments. Godzilla Mullion, one of the OCC in the PVR, is the worlds largest OCC, 10 times larger in area than the normal OCCs in the Mid-Atlantic Ridge (Ohara et al., 2001). Various plutonic rocks including mantle peridotites were recovered from the megamullion. TONGA FOREARC: The serpentine seamounts have never been observed along the forearc, on the other hand, geological cross section is recognized along the Tonga Trench inner wall including fresh mantle peridotite. IZU-OGASAWARA(BONIN)-MARIANA FOREARC: Many topographic highs are recognized along the Izu- Ogasawara-Mariana forearc. A number of igneous rocks including lavas, gabbros and serpentinized depleted peridotites; so called ophiolitic rocks were dredged from those seamounts by several investigators, who concluded that these seamounts originated from serpentinite diapirs derived from the upper parts of the mantle wedge. Remnant mantle diapir is assumed to be the depleted source peridotite of diapiric serpentinite seamount. Tonga forearc and Izu-Ogasawara-Mariana forearc may be assumed as modern analogue of the Oman ophiolite and the Trodos ophiolite, respectively.

Ishii, T.; Hirano, N.; Ohara, Y.; Bloomer, S.

2006-12-01

365

Fluid inclusion and petrological studies provide insight to the reconstruction of magma conduit systems  

NASA Astrophysics Data System (ADS)

Combined petrological and fluid inclusion studies represent a useful tool to reconstruct the pathways and the time-scale of magma ascent beneath active volcanoes. Petrological and geochemical data supply the basis for understanding the chemico-physical parameters of erupted magma evolution, and fluid inclusion geobarometry allows placing constraints on depths of magma accumulation zones in the crust. Based on this approach,a model is reported for the Island of Vulcano, which has a general applicability for other Aeolian volcanoes. The Aeolian arc consists of several recent to active volcanoes, which show variable mafic to silicic compositions and calcalkaline to shoshonitic petrochemical affinity. In most islands, such as at Vulcano, early mafic calcalkaline activity is followed by shoshonitic mafic to silicic products. Petrological studies suggest that the magmas erupted during early stages of the exposed activity (about 0.1 to 0.02 Ma) evolved by combined fractional crystallization, wall rock assimilation, and intensive mixing with mafic magmas continuously injected into the magma chamber. The younger activity tapped shallow magma chambers, in which fractional crystallization and moderate wall rock assimilation of shoshonitic basalts generated alkali rhyolites. At Vulcano, fluid inclusion data allow to identify two major magma accumulation zones located in the lower and middle crust at 21-17 km and 13-8 km depth, plus a minor one lying at 5-1 km depth. The deepest accumulation zone contains mafic melts and is located at the transition between the upper mantle and a granulitic lower crust. This reservoir has been active since the onset of the exposed volcanism, and has experienced continuous fractional crystallization, crustal assimilation and mixing with primary melts from the mantle. Slightly differentiated magmas from the deep reservoir fed accumulation zone in the middle and upper crust, or erupted directly at the surface through lateral vents. Entering of variably differentiated melts into the shallowest reservoir, located at 5-1 km depth, probably occurred shortly before magma outbreak at the surface. Similar fluid inclusion density distributions are found in other Aeolian island magmas, which leads to propose that a polybaric magma evolution occur beneath the whole Aeolian archipelago. According to our model, felsic magmas in Aeolian magmas were largely generated within magma chamber situated at middle-lower crustal depths. Magma ascent from deep-crustal magma chambers had a key role in promoting volcanic eruptions.

Frezzotti, M.; Peccerillo, A.

2008-12-01

366

Virtual Humans for Team Training in Virtual Reality  

Microsoft Academic Search

This paper describes the use of virtual humans anddistributed virtual reality to support team training,where students must learn their individual role in theteam as well as how to coordinate their actions withtheir teammates. Students, instructors, and virtualhumans cohabit a 3d, simulated mock-up of their workenvironment, where they can practice together in realisticsituations. The virtual humans can serve asinstructors for individual

Jeff Rickel; W. Lewis Johnson

1999-01-01

367

Virtual water: Virtuous impact? The unsteady state of virtual water  

Microsoft Academic Search

Virtual water,” water needed for crop production, is now being mainstreamed in the water policy world. Relying on virtual\\u000a water in the form of food imports is increasingly recommended as good policy for water-scarce areas. Virtual water globalizes\\u000a discussions on water scarcity, ecological sustainability, food security and consumption. Presently the concept is creating\\u000a much noise in the water and food

Dik Roth; Jeroen Warner

2008-01-01

368

Petrology and Geochemistry of Patuxent Range 91501, a Clast-Poor Impact-Melt from the L Chondrite Parent Body, and Lewis Cliff 88663, an L7 Chondrite.  

National Technical Information Service (NTIS)

We have performed petrologic and geochemical studies of Patuxent Range 91501, originally classified as an L7 chondrite. PAT 91501 is an unshocked homogeneous, igneous-textured ultramafic rock composed of euhedral to subhedral olivine, low-Ca pyroxene, aug...

D. W. Mittlefehldt M. M. Lindstrom

2001-01-01

369

Petrology and provenance of the Great Valley Group. Southern Klamath Mountains and northern Sacramento Valley  

SciTech Connect

Lower Cretaceous sandstone and conglomerate of the Great Valley Group rest depositionally on the southern Klamath Mountains at the north end of the Sacramento Valley. Exposures include nonmarine, shallow marine, and deep marine sediments, which are part of the Platina Formation (petrofacies). Approximately 150 sandstone point counts (500 points per section using Gazzi-Dickinson method) and 32 conglomerate clast counts indicate a Klamath provenance of mixed magmatic-arc and recycled orogenic character. Standard triangular plots and multivariate analyses (combined with paleocurrent and paleogeographic data) suggest discrete source areas within the Klamath terrane. However, the general homogeneity of both sandstone and conglomerate petrology is consistent with all of the units being included within the Platina petrofacies.

Short, P.F.; Ingersoll, R.V. (Univ. of California, Los Angeles (USA))

1990-05-01

370

Stratigraphy, petrology, and tectonic setting of the Alisitos Group, Baja California, Mexico  

NASA Astrophysics Data System (ADS)

The Alisitos Group comprises much of the wall-rocks of the western Peninsular Ranges Batholith in Baja California, Mexico; aspects of its stratigraphy, petrology, and tectonic origin are discussed. The Alisitos group was formerly designated Alisitos Formation. A higher rank of stratigraphic nomenclature is suggested because of its wide extent and lithologic diversity. Two new formations are defined within the Alisitos Group in the San Fernando area. The El Progreso Formation includes volcanic and volcaniclastic rocks mainly of silicic composition interstratified with rudist limestones. The type area is the El Progreso area. It is overlain to the southwest by the San Felipito Formation, which includes tuff-breccia, graded tuff beds, and shale as principal rock types. The main canyon of Arroyo San Fernando is designated as type area.

Beggs, J. M.

371

Global petrologic variations on the moon: a ternary-diagram approach.  

USGS Publications Warehouse

A ternary-diagram approach for determination of global petrologic variations on the lunar surface is presented that incorporates valuable improvements in our previous method of using geochemical variation diagrams. Our results are as follows: 1) the highlands contain large areas of relatively pure ferroan anorthosite; 2) the average composition of the upper lunar crust is represented by an 'anorthositic gabbro' composition; 3) KREEP/Mg-suite rocks are a minor fraction of the upper lunar crust; 4) within the farside highlands, areas of KREEP/Mg-suite rocks coincide mostly with areas of crustal thinning; 5) portions of the E limb and farside highlands have considerable amounts of a mafic, chondritic Th/Ti component (like mare basalt) whose occurrences coincide with mapped concentrations of light plains that display dark-halo craters.- from Authors

Davis, P. A.; Spudis, P. D.

1987-01-01

372

Virtual microscopy: High resolution digital photomicrography as a tool for light microscopy simulation  

Microsoft Academic Search

Recent advances in microcomputers and high resolution digital video cameras provide pathologists the opportunity to combine precision optics with digital imaging technology and develop new educational and research tools. We review recent advances in virtual microscopy and describe techniques for viewing digital images using a microcomputer-based workstation to simulate light microscopic examination, including scanning at low power to select features

Christopher L Felten; Jonathan S Strauss; Darren H Okada; Alberto M Marchevsky

1999-01-01

373

Virtual microscopy-The future of teaching histology in the medical curriculum?  

PubMed

Conventional continuing education in microscopic anatomy, histopathology, hematology and microbiology has hitherto been carried out using numerous sets of sectioned tissue specimens in a microscopy laboratory. In comparison, after digitalization of the sections it would be possible to access teaching specimens via virtual microscopy and the internet at any time and place. This would make it possible to put innumerable new learning scenarios into practice. The present article elucidates the advantages of virtual microscopy in histology instruction and presents a concept of how virtual microscopy could be introduced into the teaching of microscopic anatomy in several steps. Initially, the presently existing microscopic teaching specimens would be digitalized and made available on-line without restriction. In a second step, instruction would be shifted to an emphasis on virtual microscopy, utilizing all of the advantages offered by the technique. In a third step, the microscopic contents could be networked with other anatomical, radiological and clinical content on-line, thus opening new learning perspectives for students of human and dental medicine as well as those of medically related courses of study. The advantages and disadvantages of such a concept as well as some possibly arising consequences are discussed in the following. PMID:20971623

Paulsen, Friedrich P; Eichhorn, Michael; Bräuer, Lars

2010-10-25

374

Origin of ocean island basalts: A new perspective from petrology, geochemistry, and mineral physics considerations  

NASA Astrophysics Data System (ADS)

Consideration of petrology, geochemistry, and mineral physics suggests that ancient subducted oceanic crusts cannot be the source materials supplying ocean island basalts (OIB). Melting of oceanic crusts cannot produce high-magnesian OIB lavas. Ancient oceanic crusts (>1 Ga) are isotopically too depleted to meet the required values of most OIB. Subducted oceanic crusts that have passed through subduction zone dehydration are likely to be depleted in water-soluble incompatible elements (e.g., Ba, Rb, Cs, U, K, Sr, Pb) relative to water-insoluble incompatible elements (e.g., Nb, Ta, Zr, Hf, Ti). Melting of residual crusts with such trace element composition cannot produce OIB. Oceanic crusts, if subducted into the lower mantle, will be >2% denser than the ambient mantle at shallow lower mantle depths. This negative buoyancy will impede return of the subducted oceanic crusts into the upper mantle. If subducted oceanic crusts melt at the base of the mantle, the resultant melts are even denser than the ambient peridotitic mantle, perhaps by as much as ˜15%. Neither in the solid state nor in melt form can bulk oceanic crusts subducted into the lower mantle return to upper mantle source regions of oceanic basalts. Deep portions of recycled oceanic lithosphere are important geochemical reservoirs hosting volatiles and incompatible elements as a result of metasomatism taking place at the interface between the low-velocity zone and the cooling and thickening oceanic lithosphere. These metasomatized and recycled deep portions of oceanic lithosphere are the most likely candidates for OIB sources in terms of petrology, geochemistry and mineral physics.

Niu, Yaoling; O'Hara, Michael J.

2003-04-01

375

Potential contributions of metamorphic petrology studies in an ultra-deep drillhole in the southern Appalachians  

SciTech Connect

The proposed, ultra-deep hole in the southeast U.S. will penetrate allochthonous, medium- to high-grade metamorphic rocks of the Inner Piedmont and Blue Ridge thrust sheets. It is anticipated that the hole will then encounter autochthonous low-grade, metasedimentary cover rocks before bottoming out in crystalline Precambrian basement rocks. Metamorphic petrology in the recent past has concentrated on unraveling the physical and chemical history (P, T, X/sub fluid/, etc.) of metamorphic rocks. The techniques that have been developed are ideally suited to the study of relatively limited samples from drill core. Detailed studies of the allochthonous and autochthonous rocks from the drillhole, combined with comparable studies of the surface rocks, by metamorphic petrologists experimented with these approaches, would give a 3-dimensional picture of the PTX evolution in the region of the ultra-deep hole, and thus an idea of the geometrical, chemical, and physical changes the rocks experienced. This would place constraints on conditions of the rocks before and after thrusting and thus any tectonic models of thrusting in the southern Appalachians. With limited sampling this could be a problem, with more complete sampling it will be an advantage. The metamorphic petrology of the rocks will provide basic support for the other studies of the drill core and drillhole, most notably geochronology and stable isotopes. It should not be forgotten that in addition to the historical metamorphism, the expected, present-day conditions in the drillhole are those of burial metamorphism. The hole will present an excellent opportunity to study such active metamorphic conditions.

Speer, J.A.

1985-01-01

376

Petrologic considerations for hot dry rock geothermal site selection in the Clear Lake Region, California  

SciTech Connect

The Clear Lake area is well known for anomalous heat flow, thermal springs, hydrothermal mineral deposits, and Quaternary volcanism. These factors, along with the apparent lack of a large reservoir of geothermal fluid north of Collayomi fault make the Clear Lake area an attractive target for hot dry rock (HDR) geothermal development. Petrologic considerations provide some constraints on site selection for HDR development. Spatial and temporal trends in volcanism in the Coast Ranges indicate that magmatism has migrated to the north with time, paralleling passage of the Mendocino triple junction and propagation of the San Andreas fault. Volcanism in the region may have resulted from upwelling of hot asthenosphere along the southern margin of the subducted segment of the Gorda plate. Spatial and temporal trends of volcanism within the Clear Lake volcanic field are similar to larger-scale trends of Neogene volcanism in the Cost Ranges. Volcanism (especially for silicic compositions) shows a general migration to the north over the {approximately}2 Ma history of the field, with the youngest two silicic centers located at Mt. Konocti and Borax Lake. The Mt. Konocti system (active from {approximately} 0.6 to 0.3 Ma) was large and long-lived, whereas the Borax Lake system is much smaller but younger (0.09 Ma). Remnants of silicic magma bodies under Mt. Konocti may be in the latter stages of cooling, whereas a magma body centered under Borax Lake may be in the early stages of development. The existence of an upper crustal silicic magma body of under Borax Lake has yet to be demonstrated by passive geophysics, however, subsurface temperatures in the area as high (> 200{degrees}C at 2000 m) as those beneath the Mt. Konocti area. Based on petrologic considerations alone, the Mt. Konocti-Borax Lake area appears to be the most logical choice for HDR geothermal development in the region.

Stimac, J.; Goff, F. (Los Alamos National Lab., NM (United States)); Hearn, B.C. Jr. (US Geological Survey, Reston, VA, Branch of Lithospheric Processes (United States))

1992-01-01

377

Deep Crustal Structure beneath Large Igneous Provinces and the Petrologic Evolution of Flood Basalts  

NASA Astrophysics Data System (ADS)

We present a review of seismological constraints on deep crustal structures underlying large igneous provinces (LIPs), largely from wide-angle seismic refraction surveys. The main purpose of this review is to ascertain whether this seismic evidence is consistent with, or contrary to, petrological models for the genesis of flood basalt lavas. Where high-quality data are available beneath continental flood basalt (CFB) provinces (Emeishan, Columbia River, Deccan, Siberia), high-velocity structures (Vp ~6.9-7.5 km/sec) are typically found immediately overlying the Moho in layers of order ~5-15 km thick. Oceanic plateau (OP) LIPs exhibit similar layers, with a conspicuous layer of very high crustal velocity (Vp~7.7 km/sec) beneath the enormous Ontong-Java plateau. These structures are similar to inferred ultramafic underplating structures seen beneath active hotspots such as Hawaii, the Marqueses, and La Reunion. Petrogenetic models for flood basalt volcanism based on hot plume melting beneath mature lithosphere suggest that these deep seismic structures may consist in large part of cumulate bodies of olivine and clinopyroxene which result from ponding and deep-crustal fractionation of ultramafic primary melts. Such fractionation is necessary to produce basalts with typical MgO contents of ~6-8%, as observed for the vast bulk of observed flood basalts, from primary melts with MgO contents of order ~15-18% (or greater) such as result from hot, deep melting beneath the lithosphere. The volumes of cumulate bodies and ultramafic intrusions in the lowermost crust, often described in the literature as "underplating," are comparable to those of the overlying basaltic formations, also consistent with petrological models. Further definition of the deep seismic structure beneath such prominent LIPs as the Ontong-Java Plateau could place better constraints on flood basalt petrogenesis by determining the relative volumes of ultramafic bodies and basaltic lavas, thereby better constraining the overall process of LIP emplacement.

Richards, Mark; Ridley, Victoria

2010-05-01

378

Deep crustal structure beneath large igneous provinces and the petrologic evolution of flood basalts  

NASA Astrophysics Data System (ADS)

We present a review of seismological constraints on deep crustal structures underlying large igneous provinces (LIPs), largely from wide-angle seismic refraction surveys. The main purpose of this review is to ascertain whether this seismic evidence is consistent with, or contrary to, petrological models for the genesis of flood basalt lavas. Where high-quality data are available beneath continental flood basalt (CFB) provinces (Emeishan, Columbia River, Deccan, Siberia), high-velocity structures (Vp ˜ 6.9-7.5 km/sec) are typically found immediately overlying the Moho in layers of order ˜5-15 km thick. Oceanic plateau (OP) LIPs exhibit similar layers, with a conspicuous layer of very high crustal velocity (Vp ˜ 7.7 km/sec) beneath the enormous Ontong-Java plateau. These structures are similar to inferred ultramafic underplating structures seen beneath active hot spots such as Hawaii, the Marquesas, and La Reunion. Petrogenetic models for flood basalt volcanism based on hot plume melting beneath mature lithosphere suggest that these deep seismic structures may consist in large part of cumulate bodies of olivine and clinopyroxene which result from ponding and deep-crustal fractionation of ultramafic primary melts. Such fractionation is necessary to produce basalts with typical MgO contents of ˜6-8%, as observed for the vast bulk of observed flood basalts, from primary melts with MgO contents of order ˜15-18% (or greater) such as result from hot, deep melting beneath the lithosphere. The volumes of cumulate bodies and ultramafic intrusions in the lowermost crust, often described in the literature as "underplating," are comparable to those of the overlying basaltic formations, also consistent with petrological models. Further definition of the deep seismic structure beneath such prominent LIPs as the Ontong-Java Plateau could place better constraints on flood basalt petrogenesis by determining the relative volumes of ultramafic bodies and basaltic lavas, thereby better constraining the overall process of LIP emplacement.

Ridley, Victoria A.; Richards, Mark A.

2010-09-01

379

Deep Crustal Structure beneath Large Igneous Provinces and the Petrologic Evolution of Flood Basalts  

NASA Astrophysics Data System (ADS)

We present a review of seismological constraints on deep crustal structures underlying large igneous provinces (LIPs), largely from wide-angle seismic refraction surveys. The main purpose of this review is to ascertain whether this seismic evidence is consistent with, or contrary to, petrological models for the genesis of flood basalt lavas. Where high-quality data are available beneath continental flood basalt (CFB) provinces (Emeishan, Columbia River, Deccan, Siberia), high-velocity structures (Vp ~6.9-7.5 km/sec) are typically found immediately overlying the Moho in layers of order ~5-15 km thick. Oceanic plateau (OP) LIPs exhibit similar layers, with a conspicuous layer of very high crustal velocity (Vp~7.7 km/sec) beneath the enormous Ontong-Java plateau. These structures are similar to inferred ultramafic underplating structures seen beneath active hotspots such as Hawaii, the Marquesas, and La Reunion. Petrogenetic models for flood basalt volcanism based on hot plume melting beneath mature lithosphere suggest that these deep seismic structures may consist in large part of cumulate bodies of olivine and clinopyroxene which result from ponding and deep-crustal fractionation of ultramafic primary melts. Such fractionation is necessary to produce basalts with typical MgO contents of ~6-8%, as observed for the vast bulk of observed flood basalts, from primary melts with MgO contents of order ~15-18% (or greater) such as result from hot, deep melting beneath the lithosphere. The volumes of cumulate bodies and ultramafic intrusions in the lowermost crust, often described in the literature as “underplating,” are comparable to those of the overlying basaltic formations, also consistent with petrological models. Further definition of the deep seismic structure beneath such prominent LIPs as the Ontong-Java Plateau could place better constraints on flood basalt petrogenesis by determining the relative volumes of ultramafic bodies and basaltic lavas, thereby better constraining the overall process of LIP emplacement.

Richards, M. A.; Ridley, V. A.

2010-12-01

380

Petrology and geochemistry of lavas from the rift basins in the Gulf of California  

NASA Astrophysics Data System (ADS)

As a focus site of the recently concluded Rupturing of Continental Lithosphere and Birth of an Ocean initiative of the MARGINS program at NSF, the Gulf of California was the object of a number of investigations during the past several years. However, though studied extensively using geophysical methods, only a few basins have been studied petrologically (e.g. Alarcon, Guaymas). Here we report new major and trace element and Sr, Nd, and Pb isotope data for lavas sampled from select off-axis seamounts and outcrops of the ocean basin crust from the Lower Delfin basin in the north to the Pescadero basin in the south. Our samples provide petrologic data from locations previously unexplored. Lava samples from each location generally range from basalt to rhyolite, but rock type distribution is variable. In general, locations further south contain mostly basalts and some differentiated lavas whereas locations further north have fewer basalts and more differentiated lavas. The trace element characteristics of the basalts are highly variable, overlapping with those of the depleted mid-ocean ridge basalts (MORB) from the East Pacific Rise (EPR) segments south of the Tamayo transform to the more enriched calc-alkaline basalts in the Guaymas Basin. The 87Sr/86Sr (0.70269-0.70328), 143Nd/144Nd (0.51299-0.51311), and 206Pb/204Pb (18.476-18.805), 207Pb/204Pb (15.528-15.583), and 208Pb/204Pb (38.048-38.449) ratios of these basalts also show variability and overlap with EPR MORB and the more variable samples cored during DSDP legs 63-65 in the Gulf. The more differentiated lavas trend away from MORB towards more crustal or radiogenic values. Our results combined with literature data suggest that magmatism in the Gulf of California varies widely over short length scales, most likely reflecting multiple sources and/or contamination by different lithospheric materials.

Juda, N.; Castillo, P. R.; Lonsdale, P.

2011-12-01

381

The Distant Morphological and Petrological Features of Shock Melt Veins in the Suizhou L6 Condrite  

SciTech Connect

The morphology and petrology of distinct melt veins in the Suizhou L6 chondrite have been investigated using scanning electron microscopy, electron microprobe analyses, and Raman spectroscopy, synchrotron energy-dispersive diffraction, and transmission electron microscopy. It is found that the melt veins in the Suizhou meteorite morphologically are the simplest, straightest, and thinnest among all shock veins known from meteorites. At first glance, these veins look like fine fractures, but petrologically they are solid melt veins of chondritic composition and consist of fully crystalline materials of two distinct lithological assemblages, with no glassy material remaining. The Suizhou melt veins contain the most abundant high-pressure mineral species when compared with all other veins known in chondrites. Thus, these veins in Suizhou are classified as shock veins. All rock-forming and almost all accessory minerals in the Suizhou shock veins have been transformed to their high-pressure polymorphs, and no fragments of the precursor minerals remain in the veins. Among the 11 high-pressure mineral phases identified in the Suizhou veins, three are new high-pressure minerals, namely, tuite after whitlockite, xieite, and the CF phase after chromite. On the basis of transformation of plagioclase into maskelynite, it is estimated that the Suizhou meteorite experienced shock pressures and shock temperatures up to 22 GPa and 1000 C, respectively. Shearing and friction along shock veins raised the temperature up to 1900-2000 C and the pressure up to 24 GPa within the veins. Hence, phase transition and crystallization of high-pressure minerals took place only in the Suizhou shock veins. Fast cooling of the extremely thin shock veins is regarded as the main reason that up to 11 shock-induced high-pressure mineral phases could be preserved in these veins.

X Xie; Z Sun; M Chen

2011-12-31

382

Virtual learning model for metaverses  

Microsoft Academic Search

Virtual learning environments have been increasingly utilized in the domain of eLearning recently. Virtual worlds such as SecondLife and OpenSimulator have opened up great opportunities in this front. The major issue with virtual worlds with respect to education is lack of models that consistently describe the entire learning process. Most of the prior work was focused on building tools to

P. D. Ariyadewa; W. V. Wathsala; V. Pradeepan; R. P. D. D. T. Perera; D. A. S. Atukorale

2010-01-01

383

Remote Virtual Information Assurance Network  

Microsoft Academic Search

The use of virtualization technologies to increase the capacity and utilization of laboratory resources is widely used in\\u000a classroom environments using several workstation based virtualization products. These virtual networks are often “air gapped”\\u000a to prevent the inadvertent release of malware. This implementation however requires users to be in the classroom. A novel\\u000a extension on this concept is to design the

Ronald C Dodge JR; Corey Bertram; Daniel Ragsdale

2007-01-01

384

Stereoscopic Kiosk for Virtual Museum  

Microsoft Academic Search

In this paper, we present a stereoscopic kiosk for virtual museum, which combines techniques of stereoscopic displays, image-based rendering, virtual reality, and augmented reality. In our kiosk system, artifacts are presented as object movies, and can be integrated with both image-based panoramas and geometry-based scenes for constructing virtual museum. Two display devices are used in the kiosk: one is a

Wan-Yen Lo; Yu-Pao Tsai; Chien-Wei Chen; Yi-Ping Hung

385

The virtual case report.  

PubMed

Reports of clinical happenings are coming under increasing suspicion because of their piecemeal nature and their problematic reliance on memory. Recent research on eyewitness testimony has raised the further concern that memory of an event can be easily and unwittingly influenced by something heard or seen after the fact. Once the psychoanalyst's memory has come under the influence of whatever theory is dominant, we can expect both an overselection of clinical happenings consistent with that theory, and an unwitting alteration of those that do not agree. Seemingly true case reports may be more virtual than veridical. PMID:12391936

Spence, Donald P

2002-10-01

386

The Experimental Virtual Environment  

NSDL National Science Digital Library

The Experimental Virtual Environment (EVE) is a project being conducted by the Helsinki University of Technology and the high-performance computing and networking center in Finland. The EVE encloses the user inside three walls and a floor that are rear projection screens, and the user can interact with the environment with a head tracking unit and other sensors. A brief introduction is given on the EVE Web site, followed by examples of applications for the system, its current implementation, and descriptions of past and current projects. A thesis about the EVE implementation goes into much more detail, and there are also several theses and related documents given in the Publications section.

387

Virtual service switch  

US Patent & Trademark Office Database

Virtual service switching includes contracting to provide a requestor with a unit of computing capacity to a service within a specific time period, creating one or more plans based at least in part on the contracting, scheduling execution of the one or more plans using the computing capacity, and if a bid for at least part of the unit of computing capacity is received prior to the end of the specific time period, allocating at least part of the computing capacity based at least in part on the bid. Each of the one or more plans comprises software code and associated data.

Cohen; David (Ridgewood, NJ); Younan; James (Warwick, NY)

2013-10-22

388

The Virtual Cave  

NSDL National Science Digital Library

Dave Bunnell, a member of the National Speleological Society and cave researcher, and Djuna Bewley created this fascinating website depicting caves from all over the world. With an abundance of images and descriptions, student and educators can learn about solution, lava tube, sea, and erosional caves. When visiting the most extensive link, Solution Caves, users can take a virtual cave tour where they can learn about stalagmites, conulites, helictites, and much more. Visitors interested in taking a trip to a cave can find information about caves throughout the United States as well as suggestions on how to make the most of your trip.

Bunnell, Dave; Bewley, Djuna

389

Birds: A Virtual Exhibition  

NSDL National Science Digital Library

This site from the Virtual Museum of Canada compiles a wealth of information from five different Canadian museums into one location for the benefit of bird lovers. This site does not provide original information; rather, it links to online bird-related exhibits from each of the five museums, which can be navigated through individually. What makes this site particularly valuable is the ability to perform a search of all five museum exhibits at once, providing a comprehensive source of information for the user that builds on the strengths of each individual exhibit.

1998-01-01

390

Verner Suomi Virtual Museum  

NSDL National Science Digital Library

This virtual musuem is dedicated to the life and work of Verner E. Suomi. Prof. Suomi's interests centered around remote sensing of our environment, and so most of the rooms in the museum have this as a central theme. Topics covered include: how the air is affected by radiation (both from the sun and from the earth itself), learning about weather satellites, and a simple, interactive climate model. There is also opportunity to learn about how clouds form, and how satellite observations are used to determine winds. An applet explores the relationships between relative humidity and dew point temperature. A section on the analysis of weather data is planned.

Ackerman, Steve; Whittaker, Tom

2002-03-28

391

Virtual Turing Machine 2  

NSDL National Science Digital Library

A Turing machine is theoretical computer consisting of a finite set of internal states, a finite alphabet that includes a blank symbol, and a finite set of instructions. It has a physical head and a physical infinitely long tape, which is divided into cells. The cell values consist of the alphabet. The tape has a finite number of non-blank cells. The head can read and write to the cells and move the tape one cell to the left and one cell to the right. The Virtual Turing Machine lets you input tape values and an instruction set to see the output of a turing machine.

Ming, Paul R.

392

An entanglement-enhanced microscope  

NASA Astrophysics Data System (ADS)

Among the applications of optical phase measurement, the differential interference contrast microscope is widely used for the evaluation of opaque materials or biological tissues. However, the signal-to-noise ratio for a given light intensity is limited by the standard quantum limit, which is critical for measurements where the probe light intensity is limited to avoid damaging the sample. The standard quantum limit can only be beaten by using N quantum correlated particles, with an improvement factor of ?N. Here we report the demonstration of an entanglement-enhanced microscope, which is a confocal-type differential interference contrast microscope where an entangled photon pair (N=2) source is used for illumination. An image of a Q shape carved in relief on the glass surface is obtained with better visibility than with a classical light source. The signal-to-noise ratio is 1.35±0.12 times better than that limited by the standard quantum limit.

Ono, Takafumi; Okamoto, Ryo; Takeuchi, Shigeki

2013-09-01

393

Microscopic characterization of peptide nanostructures.  

PubMed

Peptide-based nanomaterials have been utilized for various applications from regenerative medicine to electronics since they provide several advantages including easy synthesis methods, numerous routes for functionalization and biomimicry of secondary structures of proteins which leads to design of self-assembling peptide molecules to form nanostructures. Microscopic characterization at nanoscale is critical to understand processes directing peptide molecules to self-assemble and identify structure-function relationship of the nanostructures. Here, fundamental studies in microscopic characterization of peptide nanostructures are discussed to provide insights in widely used microscopy tools. In this review, we will encompass characterization studies of peptide nanostructures with modern microscopes, such as TEM, SEM, AFM, and advanced optical microscopy techniques. We will also mention specimen preparation methods and describe interpretation of the images. PMID:21821422

Mammadov, Rashad; Tekinay, Ayse B; Dana, Aykutlu; Guler, Mustafa O

2011-07-19

394

An entanglement-enhanced microscope.  

PubMed

Among the applications of optical phase measurement, the differential interference contrast microscope is widely used for the evaluation of opaque materials or biological tissues. However, the signal-to-noise ratio for a given light intensity is limited by the standard quantum limit, which is critical for measurements where the probe light intensity is limited to avoid damaging the sample. The standard quantum limit can only be beaten by using N quantum correlated particles, with an improvement factor of ?N. Here we report the demonstration of an entanglement-enhanced microscope, which is a confocal-type differential interference contrast microscope where an entangled photon pair (N=2) source is used for illumination. An image of a Q shape carved in relief on the glass surface is obtained with better visibility than with a classical light source. The signal-to-noise ratio is 1.35±0.12 times better than that limited by the standard quantum limit. PMID:24026165

Ono, Takafumi; Okamoto, Ryo; Takeuchi, Shigeki

2013-09-12

395

Care and Feeding of the Compound Microscope  

NSDL National Science Digital Library

This lab activity from the Biotechnology Alliance for Suncoast Biology Educators is intended to demonstrate appropriate use of a microscope. It covers the basic care and operation of a compound light microscope. The lesson includes information on how a compound microscope works, a diagram of its parts, tips for usage, a practice activity, and a checklist for putting the microscope away.

Keirle, Matt

2012-07-10

396

A new world for virtual reference  

Microsoft Academic Search

Purpose – This paper aims to examine the emerging field of reference in virtual worlds and attempts to determine its place among existing reference services. The virtual world of Second Life is the focus for these virtual world services. Advantages of virtual world reference are highlighted and drawbacks are discussed. Design\\/methodology\\/approach – The paper examines two existing virtual world reference

Krista Godfrey

2008-01-01

397

Policy gaps in the virtual world  

Microsoft Academic Search

The convergence of computer and communication technologies has brought the people around the world to be more connected electronically in a virtual world. The success of Internet has opened up possibilities to create many applications in the space of the virtual world, such as the virtual libraries, the virtual shopping malls and the virtual communities, which have availed opportunities to

Muthukkaruppan Annamalai; K. M. Ehsan; N. S. N. Awang; N. A. I. N. Ahmad

2010-01-01

398

Nanophotonic three-dimensional microscope.  

PubMed

Three-dimensional (3D) optical microscopy based on integral imaging techniques is limited mainly by diffraction effects and the pitch of the microlens array used to sample the specimen. We integrate nanotechnology to the integral imaging technique and demonstrate a nanophotonic 3D microscope, where a nanophotonic lens array is used to finely sample the specimen. The resolution limitation due to diffraction is reduced by capturing images before the diffraction effects predominate and hence overcomes the bottleneck of achieving high resolution in an integral imaging 3D microscope. PMID:21657239

Rajasekharan, Ranjith; Wilkinson, Timothy D; Hands, Philip J W; Dai, Qing

2011-06-14

399

Field Experience in Virtual Schools--To Be There Virtually  

ERIC Educational Resources Information Center

|Virtual Schooling (VS) for K-12 school students using distance technologies has increased rapidly in the 21st century with the growth of online learning and virtual schools in more than 44 states in the USA and as e-learning in over 20 clusters of rural schools in New Zealand. Although VS requires a special set of teaching methods, teacher…

Compton, Lily Ki Lo; Davis, Niki; Mackey, Julie

2009-01-01

400

Ubiquitous Virtual Reality: Accessing Shared Virtual Environments through Videoconferencing Technology  

Microsoft Academic Search

This paper presents an alternative to existing methods for remotely accessing Virtual Reality (VR) systems. Com- mon solutions are based on specialised software and\\/or hardware capable of rendering 3D content, which not only restricts accessibility to specific platforms but also increases the barrier for non expert users. Our approach ad- dresses new audiences by making existing Virtual Environments (VEs) ubiquitously

Thies Pfeiffer; Matthias Weber; Bernhard Jung

2005-01-01

401

Exploring virtual worlds: success factors in virtual world marketing  

Microsoft Academic Search

Purpose – Drawing from recent work on online social networking and communities of consumption, the purpose of this paper is to explore, identify, and postulate key factors facilitating the growth and success of marketing in virtual worlds. Design\\/methodology\\/approach – An empirical study was conducted employing netnographic evidence from three different virtual worlds and related user-generated blog discussions. Findings – The

Henrikki Tikkanen; Joel Hietanen; Tuomas Henttonen; Joonas Rokka

2009-01-01

402

Field Experience in Virtual Schools--To Be There Virtually  

ERIC Educational Resources Information Center

Virtual Schooling (VS) for K-12 school students using distance technologies has increased rapidly in the 21st century with the growth of online learning and virtual schools in more than 44 states in the USA and as e-learning in over 20 clusters of rural schools in New Zealand. Although VS requires a special set of teaching methods, teacher…

Compton, Lily Ki Lo; Davis, Niki; Mackey, Julie

2009-01-01

403

Virtual reality and mixed reality for virtual learning environments  

Microsoft Academic Search

This paper explores educational uses of virtual learning environment (VLE) concerned with issues of learning, training and entertainment. We analyze the state-of-art research of VLE based on virtual reality and augmented reality. Some examples for the purpose of education and simulation are described. These applications show that VLE can be means of enhancing, motivating and stimulating learners’ understanding of certain

Zhigeng Pan; Adrian David Cheok; Hongwei Yang; Jiejie Zhu; Jiaoying Shia

2006-01-01

404

Enhanced virtual microscopy for collaborative education  

PubMed Central

Background Curricular reform efforts and a desire to use novel educational strategies that foster student collaboration are challenging the traditional microscope-based teaching of histology. Computer-based histology teaching tools and Virtual Microscopes (VM), computer-based digital slide viewers, have been shown to be effective and efficient educational strategies. We developed an open-source VM system based on the Google Maps engine to transform our histology education and introduce new teaching methods. This VM allows students and faculty to collaboratively create content, annotate slides with markers, and it is enhanced with social networking features to give the community of learners more control over the system. Results We currently have 1,037 slides in our VM system comprised of 39,386,941 individual JPEG files that take up 349 gigabytes of server storage space. Of those slides 682 are for general teaching and available to our students and the public; the remaining 355 slides are used for practical exams and have restricted access. The system has seen extensive use with 289,352 unique slide views to date. Students viewed an average of 56.3 slides per month during the histology course and accessed the system at all hours of the day. Of the 621 annotations added to 126 slides 26.2% were added by faculty and 73.8% by students. The use of the VM system reduced the amount of time faculty spent administering the course by 210 hours, but did not reduce the number of laboratory sessions or the number of required faculty. Laboratory sessions were reduced from three hours to two hours each due to the efficiencies in the workflow of the VM system. Conclusions Our virtual microscope system has been an effective solution to the challenges facing traditional histopathology laboratories and the novel needs of our revised curriculum. The web-based system allowed us to empower learners to have greater control over their content, as well as the ability to work together in collaborative groups. The VM system saved faculty time and there was no significant difference in student performance on an identical practical exam before and after its adoption. We have made the source code of our VM freely available and encourage use of the publically available slides on our website.

2011-01-01

405

When Virtual Worlds Expand  

NASA Astrophysics Data System (ADS)

The future of a virtual world depends on whether it can grow in subjective size, cultural content, and numbers of human participants. In one form of growth, exemplified by Second Life, the scope of a world increases gradually as new sponsors pay for new territory and inhabitants create content. A very different form of growth is sudden expansion, as when World of Warcraft (WoW) added entire new continents in its Burning Crusade and Lich King expansions (Lummis and Kern 2006, 2008; Corneliussen and Rettberg 2008; Sims et al. 2008). Well-established gamelike worlds have often undergone many expansions. Both the pioneer science fiction game Anarchy Online, which was launched in 2001, and Star Wars Galaxies dating from 2003, have had three, and EVE Online also from 2003 has had nine, although smaller ones. This chapter reports research on WoW's 2008 Lich King expansion, using both quantitative and qualitative methods, in order to develop theoretical ideas of the implications of expansion for virtual worlds.

Bainbridge, William Sims

406

Virtual reality via photogrammetry  

NASA Astrophysics Data System (ADS)

We wish to walk into a photograph just as Alice walked into the looking glass. From a mathematical perspective, this problem is exceedingly ill-posed (e.g. Is that a large, distant object or a small, nearby object?). A human expert can supply a large amount of a priori information that can function as mathematical constraints. The constrained problem can then be attacked with photogrammetry to obtain a great deal of quantitative information which is otherwise only qualitatively apparent. The user determines whether the object to be analyzed contains two or three vanishing points, then selects an appropriate number of points from the photon to enable the code to compute the locations of the vanishing points. Using this information and the standard photogrammetric geometric algorithms, the location of the camera, relative to the structure, is determined. The user must also enter information regarding an absolute sense of scale. As the vectors from the camera to the various points chosen from the photograph are determined, the vector components (coordinates) are handed to a virtual reality software package. Once the objects are entered, the appropriate surfaces of the 3D object are `wallpapered' with the surface from the photograph. The user is then able to move through the virtual scene. A video will demonstrate our work.

Zahrt, John D.; Papcun, George; Childers, Randy A.; Rubin, Naama

1996-03-01

407

The Russian Virtual Observatory  

NASA Astrophysics Data System (ADS)

The Russian Virtual Observatory (RVO) will be an integral component of the International Virtual Observatory (IVO). The RVO has the main goal of integrating resources of astronomical data accumulated in Russian observatories and institutions (databases, archives, digitized glass libraries, bibliographic data, a remote access system to information and technical resources of telescopes etc.), and providing transparent access for scientific and educational purposes to the distributed information and data services that comprise its content. Another goal of the RVO is to provide Russian astronomers with on-line access to the rich volumes of data and metadata that have been, and will continue to be, produced by astronomical survey projects. Centre for Astronomical Data (CAD), among other Russian institutions, has had the greatest experience in collecting and distributing astronomical data for more than 20 years. Some hundreds of catalogs and journal tables are currently available from the CAD repository. More recently, mirrors of main astronomical data resources (VizieR, ADS, etc) are now maintained in CAD. Besides, CAD accumulates and makes available for the astronomical community information on principal Russian astronomical resources.

Dluzhnevskaya, O. B.; Malkov, O. Yu.; Kilpio, A. A.; Kilpio, E. Yu.; Kovaleva, D. A.; Sat, L. A.

408

Oriental Institute Virtual Museum  

NSDL National Science Digital Library

The University of Chicago Oriental Institute Virtual Museum has recently opened its doors. The unique aspect of this museum of "history, art and archaeology of the ancient Near East" is that it uses Apple Quicktime VR (available for both Windows and Macintosh platforms from a pointer to the Apple Computer site) to take the visitor on a moving tour through selected parts of the museum. Viewers can move about museum exhibits by simply dragging their mouse to the right or left. At this time only the Egyptian and Assyrian galleries are "open," but soon the Mesopotamian, Persian, Palestinian, and Temporary Exhibits galleries will be open as well. Each exhibit is accompanied by a complete list of artifacts on exhibit, as well as connections to other Oriental Institute sites of interest, including selected photographic archives. At present, the main drawback to the site is that the artifacts are not virtually "labeled"; that is, it is very difficult for the lay user to link the artifacts being viewed to their descriptions. However, this site is a work in progress, and planned enhancements include the embedding of URLs in the QTVR panoramic movie files, and linking text and photographs of individual objects to their images in the panoramic movie. Note that each exhibit is very large (around 900 kilobytes), and that familiarity with QTVR will help in the navigation of the site.

1996-01-01

409

Virtual and real photons  

NASA Astrophysics Data System (ADS)

Maxwell did not believe in photons. However, his equations lead to electro-magnetic field structures that are considered to be photonic by Quantum ElectroDynamics (QED). They are complete, relativistically correct, and unchallenged after nearly 150 years. However, even though his far-field solution has been considered as the basis for photons, as they stand and are interpreted, they are better fitted to the concept of virtual rather than to real photons. Comparison between staticcharge fields, near-field coupling, and photonic radiation will be made and the distinctions identified. The question of similarities in, and differences between, the two will be addressed. Implied assumptions in Feynman's "Lectures" could lead one to believe that he had provided a general classical electrodynamics proof that an orbital electron must radiate. While his derivation is correct, two of the conditions defined do not always apply in this case. As a result, the potential for misinterpretation of his proof (as he himself did earlier) for this particular case has some interesting implications. He did not make the distinction between radiation from a bound electron driven by an external alternating field and one falling in a nuclear potential. Similar failures lead to misinterpreting the differences between virtual and real photons.

Meulenberg, Andrew, Jr.

2011-09-01

410

Ergito: Virtual Text  

NSDL National Science Digital Library

Ergito's Virtual Text, started in 2000, was created to provide a more timely and interactive alternative to printed scientific textbooks at the undergraduate and graduate level. This still-developing Web site covers life science writ large, including molecular biology, cell biology, genetics, biochemistry, immunology, and so on. However, only a small number of features are available free of charge. The first chapter of the molecular biology module -- Genes are DNA -- is available for free, as is Great Experiments, a collection of essays written by authors who conducted original research that has contributed greatly to our understanding of molecular and cellular biology. Great Experiments has a recently added essay by 2001 Nobel Prize winner Paul Nurse, titled "The Discovery of cdc2 as the Key Regulator of the Cell Cycle." These essays are formatted just as the Virtual Text pages are, with downloadable figures, a glossary, an online note-taking feature (notes are automatically compiled with a summary of the essay), glossary, and more. Ergito will soon make available Techniques, another free feature offering descriptions of widely used experimental protocols. Even without free access to the larger body of material in this Web site, Ergito is a fantastic resource for learning about molecular and cellular biology. Users must complete a free registration process to access this Web site.

2000-01-01

411

Virtually assisted optical colonoscopy  

NASA Astrophysics Data System (ADS)

We present a set of tools used to enhance the optical colonoscopy procedure in a novel manner with the aim of improving both the accuracy and efficiency of this procedure. In order to better present the colon information to the gastroenterologist performing a conventional (optical) colonoscopy, we undistort the radial distortion of the fisheye view of the colonoscope. The radial distortion is modeled with a function that converts the fisheye view to the perspective view, where the shape and size of polyps can be more readily observed. The conversion, accelerated on the graphics processing unit and running in real-time, calculates the corresponding position in the fisheye view of each pixel on the perspective image. We also merge our previous work in computer-aided polyp detection for virtual colonoscopy into the optical colonoscopy environment. The physical colonoscope path in the optical colonoscopy is approximated with the hugging corner shortest path, which is correlated with the centerline in the virtual colonoscopy. With the estimated distance that the colonoscope has been inserted, we are able to provide the gastroenterologist with visual cues along the observation path as to the location of possible polyps found by the detection process. In order to present the information to the gastroenterologist in a non-intrusive manner, we have developed a friendly user interface to enhance the optical colonoscopy without being cumbersome, distracting, or resulting in a more lackadaisical inspection by the gastroenterologist.

Marino, Joseph; Qiu, Feng; Kaufman, Arie

2008-04-01

412

Weathering of Igneous, Metamorphic, and Sedimentary Rocks in a Semi-Arid Climate - An Engineering Application of Petrology  

NSDL National Science Digital Library

The identification of clay mineral assemblages in soils provides a unique opportunity to demonstrate how basic principles of petrology and geochemistry are applied to engineering design criteria in construction site preparation. Specifically, the problem investigates the conditions leading to the formation of smectite in soils and the resulting construction risk due to soil expansion. Students examine soils developed on igneous, metamorphic, and sedimentary rocks near Denver, Colorado. The field locations are areas of suburban growth and several have expansive soil problems. The 2-week exercise includes sample collection, description, and preparation, determining clay mineralogy by XRD, and measurement of Atterberg Plasticity Indices. This problem develops skills in X-ray diffraction analysis as applied to clay mineralogy, reinforces leacture material on the geochemistry of weathering, and demonstrates the role of petrologic characterization in site engineering.

Harrison, Wendy; Wendlandt, Ric

413

Bringing the Field into the Classroom by Using Dynamic Digital Maps to Engage Undergraduate Students in Petrology Research  

NSDL National Science Digital Library

This article describes the use of Dynamic Digital Maps (DDMs) in undergraduate petrology courses. A DDM is a stand-alone computer program that presents interactive geologic maps, digital images, movies, animations, text and data. DDMs were developed for use in two undergraduate research projects, and impacts on student learning were evaluated by administering assessments on students before and after participation in one of the projects. Researchers found significant gains in both students' confidence in their ability to do research and to understand petrology, and noted that DDMs are versatile and can potentially be adapted effectively from 100-level introductory geology labs to research-oriented gradute level courses and in a variety of geologic subdisciplines.

Boundy, Theresa; Condit, Christopher

2004-09-01

414

Nature Study with the Microscope.  

ERIC Educational Resources Information Center

|Identifies specific instruction difficulties, potential problems, solutions, and activities for successful use of microscopes in the classroom. Procedures are outlined for guiding students in creating their own slides with monocotyledon and dicotyledon stems, fern spores, stomata, lichens, and red onions. (MCO)|

Sollberger, Dwight E.

1991-01-01

415

Social Life Under the Microscope?  

Microsoft Academic Search

Video is an important new instrument for sociological research, sometimes welcomed as the 'microscope' of social science. It provides access to important and otherwise difficult to examine aspects of human interaction. Moreover, because video captures practice in its lived production as 'another next first time' (Garfinkel 1992), it makes it possible to study practical creativity - the way in which

Monika BÃŒscher

2005-01-01

416

Microscopic cross sections: An utopia?  

NASA Astrophysics Data System (ADS)

The increasing need for cross sections far from the valley of stability poses a challenge for nuclear reaction models. So far, predictions of cross sections have relied on more or less phenomenological approaches, depending on parameters adjusted to available experimental data or deduced from systematical relations. While such predictions are expected to be reliable for nuclei not too far from the experimentally known regions, it is clearly preferable to use more fundamental approaches, based on sound physical bases, when dealing with very exotic nuclei. Thanks to the high computer power available today, all major ingredients required to model a nuclear reaction can now be (and have been) microscopically (or semi-microscopically) determined starting from the information provided by a nucleon-nucleon effective interaction. We have implemented all these microscopic ingredients in the TALYS nuclear reaction code, and we are now almost able to perform fully microscopic cross section calculations. The quality of these ingredients and the impact of using them instead of the usually adopted phenomenological parameters will be discussed.

Hilaire, S.; Koning, A. J.; Goriely, S.

2010-10-01

417

Emission microscope observation of FEAs  

Microsoft Academic Search

Electron emission from a FEA was magnified by making use of an emission microscope, and the uniformity of the electron emission was examined. By resolving the electron emission from the each microtip, the stability of electron emission from a single microtip was successfully measured. Magnification factors of 100 and spatial resolution of 6 ?m are achieved. The uniformity of the

Hideaki Nakane; Koichi Yamane; Yasufumi Muto; Satoru Kawata; Hiroshi Adachi

1999-01-01

418

Ames MER Microscopic Imager Toolkit.  

National Technical Information Service (NTIS)

The Mars Exploration Rovers, Spirit and Opportunity, have spent several successful months on Mars, returning gigabytes of images and spectral data to scientists on Earth. One of the instruments on the MER rovers, the Athena Microscopic Imager (MI), is a f...

R. Sargent M. Deans C. Kunz M. Sims K. Herkenhoff

2005-01-01

419

Developing Trust in Virtual Teams  

ERIC Educational Resources Information Center

Rapid globalization, advances in technology, flatter organizational structures, synergistic cooperation among firms, and a shift to knowledge work environments have led to the increasing use of virtual teams in organizations. Selecting, training, and socializing employees in virtual teamwork has therefore become an important human resource…

Germain, Marie-Line

2011-01-01

420

Virtual Reality, Art and Entertainment  

Microsoft Academic Search

Most existing research on virtual reality concerns issues close to theinterface, primarily how to present an underlying simulated world in aconvincing fashion. However, for virtual reality to achieve its promise as arich and popular artistic form, as have the novel, cinema, and television,we believe it will be necessary to explore well beyond the interface, to thoseissues of content and style

Joseph Bates

1992-01-01

421

The human agent virtual environment  

Microsoft Academic Search

In this paper we describe a multi-agent simulation called the Human Agent Virtual Environment (or HAVE). HAVE is a test bed to explore agent-environment interaction in multi- agent simulation for defence applications. The primary re- search driver in the development of HAVE is to explore representations of virtual environments in which both hu- mans and agents are situated, perceive these

Michael Papasimeon; Adrian R. Pearce; Simon Goss

2007-01-01

422

Virtual Tembaga Ordering System (VTOS)  

Microsoft Academic Search

This paper presents the development of Virtual Tembaga Ordering System (VTOS) that focused on interactivity in 3D product using Virtual Reality Modeling Language (VRML). VTOS was developed using PHP language with the integration of VRML capabilities in order to adapt real shopping experience for users while examining the product before purchase. Users\\/customers have the chance to view the 3D object

H. M. Omar; N. A. A. A. Bakar; N. M. Nor

2010-01-01

423

Active Perception in Virtual Humans  

Microsoft Academic Search

We propose and demonstrate a new paradigm for active vi- sion research which draws upon recent advances in the fields of artificial life and computer graphics. A software alterna- tive to the prevailing hardware vision mindset, animat vision prescribes artificial animals, or animats, situated in physics- based virtual worlds as autonomous virtual robots with ac- tive perception systems. To be

Tamer F. Rabie; Demetri Terzopoulos

2000-01-01

424

Virtual Scene for Telerobotic Operation  

Microsoft Academic Search

In this presents we concentrate our effort on building virtual modeling environments which can provide instant visualization for humanoid teleoperation system as the visual feedback is an essential part of any telerobotic system. Here virtual scene includes reconstruction of humanoid robot BHR02, and objects like table etc, where as reconstruction of BHR02 and interface for rendering the data of real

M. U. Keerio; A. F. Chandio; A. Khawaja; A. R. Jafri

2006-01-01

425

The Virtual CVD Learning Platform  

Microsoft Academic Search

The virtual CVD learning platform provides a capstone experience in which students synthesize engineering science and statistics principles. They apply design of experiments (DOE) in the context similar to that of industry with a wider design space than is typically seen in the undergraduate lab. The virtual CVD learning platform contains a numerical simulation of a chemical-vapor deposition (CVD) reactor

Milo D. Koretsky; Danielle Amatore; Connelly Barnes; Sho Kimura

2006-01-01

426

The Web and Virtual Schools  

ERIC Educational Resources Information Center

|This paper focuses on the role of government in the growth of Web-based virtual schools. First, it describes the current evolving situation. It then discusses ways in which U.S. federal, state, and local governments have developed virtual schools, and presents some information about international initiatives in this area. It also identifies…

Schrum, Lynne

2005-01-01

427

Visiting virtual reality museum exhibits  

Microsoft Academic Search

Summary form only given. Virtual museums provide ways to capture the content of a real museum in a digital (electronic) form and make this digital form more universally available. This exhibit demonstrates a novel method for digitally recording entire museum exhibits and allowing them to be explored in virtual reality. The methodology allows anyone with access to the Internet or

B. Hemminger; G. Bolas; D. Schiff

2004-01-01

428

Visiting virtual reality museum exhibits  

Microsoft Academic Search

Virtual museums provide ways to capture the content of a real museum in a digital (electronic) form and make this digital form more universally available. This exhibit demonstrates a novel method for digitally recording entire museum exhibits and allowing them to be explored in virtual reality. The methodology allows anyone with access to the Internet or a PC to experience

Bradley M. Hemminger; Gerald Bolus; Doug Schiff

2004-01-01

429

Panoramic Views in Virtual Sarajevo  

Microsoft Academic Search

The Virtual Sarajevo project provides a detailed model of the city of Sarajevo which people can explore interactively. An important part of the presentation of this city model are the panoramic views. This paper will describe the process of creating panoramic pictures for our model. We discuss two ways of inserting panoramic viewpoints in the virtual model using the Anchor

Emir Beca

430

Weak deeply virtual Compton scattering  

Microsoft Academic Search

We extend the analysis of the deeply virtual Compton scattering process to the weak interaction sector in the generalized Bjorken limit. The virtual Compton scattering amplitudes for the weak neutral and charged currents are calculated at the leading twist within the framework of the nonlocal light-cone expansion via coordinate space QCD string operators. Using a simple model, we estimate cross

A. V. Radyushkin; A. Psaker

2007-01-01

431

Dedicated online virtual reference instruction.  

PubMed

To facilitate nursing students' information literacy skills and enhance traditional library user services, academic librarians have developed synchronous (real-time) online virtual reference instruction in nursing research classes. The authors discuss collaborative efforts of nursing and library faculty in planning, implementing, and evaluating a discipline-specific virtual reference pilot program. PMID:16292145

Guillot, Ladonna; Stahr, Beth; Plaisance, Louise

432

Virtual Ed. Faces Sharp Criticism  

ERIC Educational Resources Information Center

|It's been a rough time for the image of K-12 virtual education. Studies in Colorado and Minnesota have suggested that full-time online students are struggling to match the achievement levels of their peers in brick-and-mortar schools. Articles in "The New York Times" questioned not only the academic results for students in virtual schools, but…

Quillen, Ian

2011-01-01

433

Virtual Reality, Combat, and Communication.  

ERIC Educational Resources Information Center

|Presents a brief examination of the evolution of virtual reality devices that illustrates how the development of this new medium is influenced by emerging technologies and by marketing pressures. Notes that understanding these influences may help prepare for the role of technical communicators in building virtual reality applications for…

Thrush, Emily Austin; Bodary, Michael

2000-01-01

434

Virtual Ed. Faces Sharp Criticism  

ERIC Educational Resources Information Center

It's been a rough time for the image of K-12 virtual education. Studies in Colorado and Minnesota have suggested that full-time online students are struggling to match the achievement levels of their peers in brick-and-mortar schools. Articles in "The New York Times" questioned not only the academic results for students in virtual schools, but…

Quillen, Ian

2011-01-01

435

The Web and Virtual Schools  

ERIC Educational Resources Information Center

This paper focuses on the role of government in the growth of Web-based virtual schools. First, it describes the current evolving situation. It then discusses ways in which U.S. federal, state, and local governments have developed virtual schools, and presents some information about international initiatives in this area. It also identifies…

Schrum, Lynne

2005-01-01

436

DRA Virtual Cockpit Research Program.  

National Technical Information Service (NTIS)

The aim of this paper is to describe work in progress at the Defence Research Agency (DRA) Farnborough on the Virtual Cockpit, with particular emphasis on format design and development. The paper reviews the reasons why the concept of the Virtual Cockpit ...

J. Ineson

1994-01-01

437

Virtual Communities in Health Care  

Microsoft Academic Search

A virtual community is a social entity involving several individuals who relate to one another by the use of a specific communication technology that bridges geographic distance. Traditional communities are determined by factors such as geographic proximity, organizational structures or activities shared by the members of the community. The concept “virtual” implies properties that unlike these of a traditional community

George Demiris

438

The Geography of Virtual Questioning  

ERIC Educational Resources Information Center

|This article explores the geography of virtual questioning by using geographic information systems to study activity within the Florida Electronic Library "Ask a Librarian" collaborative chat service. Researchers mapped participating libraries throughout the state of Florida that served as virtual "entry portals" for users as they asked questions…

Mon, Lorri; Bishop, Bradley Wade; McClure, Charles R.; McGilvray, Jessica; Most, Linda; Milas, Theodore Patrick; Snead, John T.

2009-01-01

439

Learning Experience with Virtual Worlds  

ERIC Educational Resources Information Center

|Virtual worlds create a new opportunity to enrich the educational experience through media-rich immersive learning. Virtual worlds have gained notoriety in games such as World of Warcraft (WoW), which has become the most successful online game ever, and in "general purpose" worlds, such as Second Life (SL), whose participation levels (more than…

Wagner, Christian

2008-01-01

440

Towards a Reactive Virtual Trainer  

Microsoft Academic Search

A Reactive Virtual Trainer (RVT) is an Intelligent Virtual Agent (IVA) capable of presenting physical exercises that are to be performed by a human, monitoring the user and providing feedback at different levels. Depend- ing on the motivation and the application context, the exercises may be general ones of fitness to improve the user's physical condition, special exercises to be

Zsófia Ruttkay; Job Zwiers; Herwin Van Welbergen; Dennis Reidsma; J. Gratch; M. Young; R. Aylett; D. Ballin; P. Olivier

2006-01-01

441

Virtual reality orthopedic surgery simulator  

Microsoft Academic Search

This paper describes a highly interactive virtual reality orthopedic surgery simulator. The simulator allows surgeons to use various surgical instruments to operate on virtual rigid anatomic structures, such bones, prostheses and bone grafts, to simulate every procedure on the rigid structures for complex orthopedic surgeries, including arthroplasty, corrective or open osteotomy, open reduction of fractures and amputation. A comparative study

Ming-Dar Tsai; Ming-Shium Hsieh; Shyan-Bin Jou

2001-01-01

442

IS leadership in virtual organizations  

Microsoft Academic Search

This paper analyzed the organizational architectures of three different virtual organizations: the network, boundaryless, and learning organizations. Challenges and opportunities for IS leaders in virtual organizations were identified and leadership roles for IS leaders in these emergent organizational forms were discussed. The paper suggests that the traditional leadership role of the IS professional as chief information officer needs to be

Karin Klenke

1996-01-01

443

Interactive Storytelling with Virtual Identities  

Microsoft Academic Search

Stories form an integral part of our lives. Interactive storytelling enables the participant to actively explore the story world. However, interactive storytelling has problems such as the problem of narrative flow, the character's knowledge of the world, internal consistency, time and ease of creation. We introduce the concept of using virtual identities for interactive storytelling in virtual environments and discuss

M. Greeff; V. Lalioti

444

Developing Trust in Virtual Teams  

ERIC Educational Resources Information Center

|Rapid globalization, advances in technology, flatter organizational structures, synergistic cooperation among firms, and a shift to knowledge work environments have led to the increasing use of virtual teams in organizations. Selecting, training, and socializing employees in virtual teamwork has therefore become an important human resource…

Germain, Marie-Line

2011-01-01

445

Virtual Communities and Social Capital  

Microsoft Academic Search

Robert Putnam (1993) has developed a theory of social capital to explain the effect of decreasing community participation and civic engagement on declining institutional performance. Subsequently, there has been much speculation as to whether emerging virtual communities can counteract this trend. We apply the findings of computer-mediated communication and virtual communities to the networks, norms, and trust of social capital

Anita Blanchard; Tom Horan

1998-01-01

446

Virtual Communities as Narrative Processes  

Microsoft Academic Search

By facing the problem to describe the history of a virtual community as the sequence of events generated by its participants, a dierent perception of the meaning of communitywares emerges. This paper describes a proposal for a virtual community system based on the narrative process that supports the social evolution of the community.

Marco Benini; Federico Gobbo

447

Virtual cathode microwave devices -- Basics  

SciTech Connect

Unlike a conventional microwave tube, a virtual-cathode device operates above the space-charge limit where the depth of the space-charge potential can cause electron reflection. The region associated with this electron reflection is referred to as a virtual cathode. Microwaves can be generated through oscillations in the position of the virtual cathode and through the bunching of electrons trapped in a potential well between the real and virtual cathodes. These two mechanisms are competitive. There are three basic classes of virtual cathode devices: (1) reflex triode; (2) reditron and side-shoot vircator; and (3) reflex diode or vircator. The reflex diode is the highest power virtual-cathode device. For the reflex diode the energy exchange between the beam and electromagnetic wave occurs in both the axial and radial directions. In some designs the oscillating-virtual-cathode frequency exceeds the reflexing-electron frequency exceeds the oscillating-virtual-cathode frequency. For the flex diode a periodic disruption in magnetic insulation can modulate the high- frequency microwave power. Overall, particle-in-cell simulation predictions and axial reflex diode experiments are in good agreement. Although frequency stability and phase locking of the reflex diode have been demonstrated, little progress has been made in efficiency enhancement. 58 refs., 11 figs.

Thode, L.E.; Snell, C.M.

1991-01-01

448

Virtual Communities: A Bibliometric Analysis  

Microsoft Academic Search

Virtual communities are a popular phenomenon today. They are significantly altering the specifics of how people work, spend their free time and interact socially. Moreover, they have been receiving growing attention in the academic literature. This study aims to identify and analyze the current academic literature in virtual communities using bibliometric analysis, and thus gain insight into its related body

Mikko O. J. Laine

2009-01-01

449

Virtual Schools and Educational Futures.  

ERIC Educational Resources Information Center

Considers issues relating to virtual schools. Topics include types of virtual schools; predictions of the ways technology will change society; quality assurance; costs; parental supervision; teaching without body language cues; socialization and the aims of education; and culture shifts and computer-mediated technology. (LRW)

Russell, Glenn

2001-01-01

450

Introduction and evaluation of virtual microscopy in teaching veterinary cytopathology.  

PubMed

Virtual microscopy (VM) uses a computer to view digitized slides and is comparable to using a microscope to view glass slides. This technology has been assessed in human medical education for teaching histology and histopathology, but, to the authors' knowledge, no one has evaluated its use in teaching cytopathology in veterinary medical education. We hypothesize that students will respond positively to the use of VM for viewing cytopathology preparations and that the technology can be successfully used for student assessment. To test this hypothesis, we surveyed students regarding their level of satisfaction with features of the VM system, their preference for use of VM in the curriculum, and the potential influence virtual slides may have on student study habits; student performance on a traditional cytopathology practical examination and a similar exam using VM was evaluated. Our results show that student perception of the VM system is generally very positive, with some concerns about resolution and the need for continued exposure to traditional microscopy. Within the curriculum, students indicated a preference for the option of using virtual slides for studying and take-home exercises. Overwhelmingly, students wanted either hybrid laboratory sessions or sessions using glass slides with virtual slides available for study and review. Students identified many VM test-taking features as advantageous compared with traditional glass-slide practical exams as traditionally administered. However, students indicated a strong preference for continued use of traditional microscopy for graded practical exams. Students may be more likely to study slides in preparation for practical examinations if virtual slides are available. Results also indicate that VM can be used successfully for assessment purposes, but students should receive training in using virtual slides if the technology will be used for assessment. PMID:18287470

Neel, Jennifer A; Grindem, Carol B; Bristol, David G

2007-01-01

451

Virtual Stationary Automata for Mobile Networks.  

National Technical Information Service (NTIS)

We define a programming abstraction for mobile networks called the Virtual Stationary Automata programming layer, consisting of real mobile clients, virtual timed I/O automata called virtual stationary automata (VSAs), and a communication service connecti...

S. Dolev S. Gilbert L. Lahiani N. Lynch T. Nolte

2005-01-01

452

Virtual Image Display for Space Flight Simulator.  

National Technical Information Service (NTIS)

This report describes the addition of virtual display imagery to a spacecraft rendezvous and docking simulator. The virtual image display is an optical system which accepts inputs from two image generators and produces a superimposed, virtual image. The m...

T. P. Neuberger W. E. Myles U. W. Ludwig

1966-01-01

453

Crustal Assimilation at Mid-Ocean Ridges Using Major and Trace Elements, Volatiles, Oxygen Isotopes and Petrologic Modeling  

Microsoft Academic Search

While the majority of eruptions at spreading centers produce lavas with relatively homogeneous mid-ocean ridge basalt (MORB) compositions, the formation of tholeiitic andesites and dacites at mid-ocean ridges (MOR) remains a petrologic enigma. Andesitic and dacitic lava flows have been observed and sampled at several different locations along the global MOR system; including propagating ridge tips at ridge-transform intersections on

Dorsey Wanless; Michael Perfit; W. Ian Ridley; Emily Klein; Paul Wallace; John Valley; Craig Grimes

2010-01-01

454

The geology and coal petrology of a Pleistocene lignite profile at Horemi mine, Megalopolis Basin, Peloponnese (southern Greece)  

Microsoft Academic Search

The present study describes the geology, coal petrology and geochemistry of a Pleistocene coal-bearing succession at Horemi mine, Megalopolis Basin (southern Greece). Within a 45-m interval 9 coal seams are exposed, ranging in thickness from 20 cm to 10 m.Reflectances measured on the maceral-type eu-ulminite B range between 0.24 and 0.31% mean Rrandom. This indicates a coalification stage in the

V. Sakorafa; K. Michailidis

1997-01-01

455

Use of Potential Fields Data to Identify Petrological Controls on Seismicity within South-Central and Southeastern Alaska  

Microsoft Academic Search

We have used data from regional gravity and aeromagnetic surveys to determine how variations in petrological properties of the upper plate(s) and subducting lower plate(s) influence the concentration of background seismicity in south-central and southeastern Alaska, as well as possible controls on asperities that ruptured during great earthquakes along the plate margin. In the Prince William Sound region it appears

D. I. Doser; A. M. Veilleux; H. Rodriguez; A. de La Pena; N. Mankhemthong

2010-01-01

456

Alpine metamorphic evolution of Ligurian Alps (North-West Italy): chemography and petrological constraints inferred from metamorphic climax assemblages  

Microsoft Academic Search

The up-to-date petrological and microtextural information on the Ligurian Alps indicates that the metamorphic rocks from the oceanic lithosphere and the paleo-European continental margin underwent an alpine-type metamorphic evolution characterized by low dT\\/dP gradients. In particular, rocks from the Ligurian-Piedmontese oceanic lithosphere underwent an alpine metamorphism typical of alpine-type blueschist rocks. The distribution of the alpine metamorphic facies in paleo-European

B. Messiga

1987-01-01

457

Mineralogy and petrology of amoeboid olivine inclusions in CO3 chondrites: Relationship to parent-body aqueous alteration  

Microsoft Academic Search

Petrographic and mineralogic studies of amoeboid olivine inclusions (AOIs) in CO3 carbonaceous chondrites reveal that they are sensitive indicators of parent-body aqueous and thermal alteration. As the petrologic subtype increases from 3.0 to 3.8, forsteritic olivine (Fa0-1) is systematically converted into ferroan olivine (Fa60-75). We infer that the Fe, Si and O entered the assemblage along grain boundaries, forming ferroan

Lysa J. Chizmadia; Alan E. Rubin; John T. Wasson

2002-01-01

458

Virtual autopsy in hanging.  

PubMed

The aim of the study was to compare postmortem computed tomographic (CT) imaging findings from a case of hanging with the autopsy findings. The CT showed a good match with autopsy findings especially for bone, soft tissue, and spinal injuries. The CT images of the injuries of the neck obtained by CT scan clearly showed the ligature mark, the hemorrhagic suffusion in the soft tissue (thickening of derma) and in the muscles (sternocleidomastoid) of the neck. Furthermore, CT 3-dimensional reconstruction showed brain edema, fracture of the left posterior horn of the hyoid bone, and a grade 1 retrolisthesis of C5 on C6. This last finding was not detected by autopsy because of the anterior approach that is frequently used in necropsy technique. Nevertheless, the CT virtual autopsy did not show vascular findings (like Amussat mark) because a barium mixture was not injected in the body. PMID:23629397

Polacco, Matteo; D'Alessio, Pasquale; Ausania, Francesco; Zobel, Bruno; Pascali, Vincenzo Lorenzo; d'Aloja, Ernesto; Miscusi, Massimo; De-Giorgio, Fabio

2013-06-01

459

Automated virtual colonoscopy  

NASA Astrophysics Data System (ADS)

Virtual colonscopy (VC) is a minimally invasive alternative to conventional fiberoptic endoscopy for colorectal cancer screening. The VC technique involves bowel cleansing, gas distension of the colon, spiral computed tomography (CT) scanning of a patient's abdomen and pelvis, and visual analysis of multiplanar 2D and 3D images created from the spiral CT data. Despite the ability of interactive computer graphics to assist a physician in visualizing 3D models of the colon, a correct diagnosis hinges upon a physician's ability to properly identify small and sometimes subtle polyps or masses within hundreds of multiplanar and 3D images. Human visual analysis is time-consuming, tedious, and often prone to error of interpretation.We have addressed the problem of visual analysis by creating a software system that automatically highlights potential lesions in the 2D and 3D images in order to expedite a physician's interpretation of the colon data.

Hunt, Gordon W.; Hemler, Paul F.; Vining, David J.

1997-05-01

460

MSN Virtual Earth  

NSDL National Science Digital Library

Geographers, urban planners, and those with a penchant for the spatial always enjoy knowing as much as they can about a given locale, and they especially enjoy knowing about spatial relationships in a given locale. For those aforementioned persons, MSN's Virtual Earth website will be one that is quite worthy of numerous visits. Drawing on detailed aerial photographs of the United States, visitors can look at photographs of their home, their business, or a local sports stadium. Visitors can also type in city names, and zoom in on various features at their leisure. A real treat is offered by the tabs feature, which allows visitors to look for local businesses, such as book stores and pharmacies in any given locale. A "scratch pad" also keeps track of recently visited destinations as well. All in all, this site can be both quite helpful and, at times, somewhat addictive.

461

Virtual Presentation Assistant  

NSDL National Science Digital Library

In these tumultuous times, it seems like more and more people want to win friends and influence people. Of course, there are enterprising souls who would attempt to sell you their insights into the art of oratory and such, but this website gives away such prized material at no cost to you, gentle browser. Virtual Presentation Assistant is an online tutorial dedicated to the art and skill of public speaking, and the site is maintained by the dedicated staff of the communication studies department at the University of Kansas. Simple in its design, the site covers such topics as selecting an appropriate theme for a speech, how to research said speech, and supporting your primary points. If all of this material doesn’t whet one’s appetite, the site also contains a selection of links to other sites that deal with the subject at hand.

462

Virtual Reference Desk  

NSDL National Science Digital Library

The Virtual Reference Desk, a project of the ERIC (Educational Resources Information Center) Clearinghouse on Information and Technology and the US National Library of Education, was established to connect the K-12 community to digital reference experts in all fields. At the heart of the site is the AskA+ Locator, a metapage that links to interactive ready reference sites in 21 subjects including arts, health, language arts, sciences, social studies and math. Each site is similar in that it takes questions in its field of expertise and answers those questions. Each site annotation contains author, audience, and contact information, as well as a description of the service. Information for organizations interested in starting up AskA services is provided. In addition, VRD maintains a mailing list, Dig_Ref for those interested in digital reference service.

1997-01-01

463

VIRTUAL REALITY HYPNOSIS  

PubMed Central

Scientific evidence for the viability of hypnosis as a treatment for pain has flourished over the past two decades (Rainville, Duncan, Price, Carrier and Bushnell, 1997; Montgomery, DuHamel and Redd, 2000; Lang and Rosen, 2002; Patterson and Jensen, 2003). However its widespread use has been limited by factors such as the advanced expertise, time and effort required by clinicians to provide hypnosis, and the cognitive effort required by patients to engage in hypnosis. The theory in developing virtual reality hypnosis was to apply three-dimensional, immersive, virtual reality technology to guide the patient through the same steps used when hypnosis is induced through an interpersonal process. Virtual reality replaces many of the stimuli that the patients have to struggle to imagine via verbal cueing from the therapist. The purpose of this paper is to explore how virtual reality may be useful in delivering hypnosis, and to summarize the scientific literature to date. We will also explore various theoretical and methodological issues that can guide future research. In spite of the encouraging scientific and clinical findings, hypnosis for analgesia is not universally used in medical centres. One reason for the slow acceptance is the extensive provider training required in order for hypnosis to be an effective pain management modality. Training in hypnosis is not commonly offered in medical schools or even psychology graduate curricula. Another reason is that hypnosis requires far more time and effort to administer than an analgesic pill or injection. Hypnosis requires training, skill and patience to deliver in medical centres that are often fast-paced and highly demanding of clinician time. Finally, the attention and cognitive effort required for hypnosis may be more than patients in an acute care setting, who may be under the influence of opiates and benzodiazepines, are able to impart. It is a challenge to make hypnosis a standard part of care in this environment. Over the past 25 years, researchers have been investigating ways to make hypnosis more standardized and accessible. There have been a handful of studies that have looked at the efficacy of using audiotapes to provide the hypnotic intervention (Johnson and Wiese, 1979; Hart, 1980; Block, Ghoneim, Sum Ping and Ali, 1991; Enqvist, Bjorklund, Engman and Jakobsson, 1997; Eberhart, Doring, Holzrichter, Roscher and Seeling, 1998; Perugini, Kirsch, Allen, et al., 1998; Forbes, MacAuley, Chiotakakou-Faliakou, 2000; Ghoneim, Block, Sarasin, Davis and Marchman, 2000). These studies have yielded mixed results. Generally, we can conclude that audio-taped hypnosis is more effective than no treatment at all, but less effective than the presence of a live hypnotherapist. Grant and Nash (1995) were the first to use computer-assisted hypnosis as a behavioural measure to assess hypnotizability. They used a digitized voice that guided subjects through a procedure and tailored software according to the subject’s unique responses and reactions. However, it utilized conventional two-dimensional screen technology that required patients to focus their attention on a computer screen, making them vulnerable to any type of distraction that might enter the environment. Further, the two-dimensional technology did not present compelling visual stimuli for capturing the user’s attention.

Askay, Shelley Wiechman; Patterson, David R.; Sharar, Sam R.

2010-01-01

464

[Virtual reality in medicine].  

PubMed

The methods of virtual reality (VR) will come to play a routine part in the work of hospitals. It is difficult to understand and explain what VR means in medicine and its scope in medicine. This paper distinguishes the four functional categories of Immersive VR, Desktop VR, Pseudo VR and Inverse VR. Immersive VR uses a head-mounted display and data gloves as input devices, while Desktop VR uses VR shutter glasses and a 3D input device such as the 3D mouse. Pseudo VR comprises interactive controllable animation. Inverse VR uses, for example, biosignals as an input device in order to support the computer user in the real world. This paper discusses the potential applications of the four categories of VR in medicine with reference to topical projects. PMID:8588036

Völter, S; Krämer, K L

1995-09-01

465

Virtual FlyLab  

NSDL National Science Digital Library

This site is maintained by Robert Deshamais and Gary Novak of California State University at Los Angeles. Users can play the role of a research geneticist while learning the principles of genetic inheritance. Users design matings between male and female fruit flies carrying one or more genetic mutations and then click the "mate" button. The program applies known Mendelian rules to produce offspring and then asks users to deduce the rules based on the "experimental" results. The program can demonstrate such genetic mechanisms as: Mendelian ratios for dominant/recessive traits, modifications of Mendelian ratios due to sex-linkage, monozygous lethals, or epistasis. Virtual Flylab seeks "to provide students with an experience in scientific reasoning and so does not provide information on the nature of the mutations; students must discover these for themselves". The resources at this site can serve as a supplement to a genetics lecture or lab or as a review of basic genetics.

1996-01-01

466

Virtual Landscapes of Texas  

NSDL National Science Digital Library

Whether real or virtual, Texas has a great deal of landscape. The people at the library at the University of Texas at Austin know this quite well, and they have put together this delightful online archive of public domain documents that deal with various landscapes throughout the state. As the introductory essay on the site notes, "This suite of public domain documents was selected as a foundation to preserve and to widen access to early writings on the geology of Texas." Visitors can use the online search engine to look for specific materials, or they can peruse them via an alphabetical listing. All told, there are well over sixty full-text documents here, including geological study reports from the late 19th century, drought surveys, and extended treatises on the effectiveness of various road-building materials.

467

Virtual Anaesthesia Textbook  

NSDL National Science Digital Library

Ten years ago, Chris Thompson conceived of an idea for a high-quality, collaborative, online textbook dedicated to the field of anesthesia. Soon afterwards, the project was started, and with the assistance of numerous practitioners and researchers, this virtual textbook was created. While the site's use of frames can be a bit distracting, the organization of the material here is easy enough to understand and navigate. Along the left-hand side of the homepage, there are several primary sections, including "Professional Issues", "Basic Sciences", and "Patient Care". Within each section, users will find a mix of content created specifically for this site, along with links that will redirect them to other external sites. The "Patient Care" area is quite good, as it gets down to the nuts and bolts of such practical matters as positioning the patient, dealing with post-operative pain management, and intubations.

468

Virtual reality and anthropology.  

PubMed

Since the discovery of the Tyrolean Iceman in 1991 advanced imaging and post processing techniques were successfully applied in anthropology. Specific techniques include spiral computed tomography and 3-dimensional reconstructions including stereolithographic and fused deposition modeling of volume data sets. The Iceman's skull was the first to be reproduced using stereolithography, before this method was successfully applied in preoperative planning. With the advent of high-end graphics workstations and biomedical image processing software packages, 3-dimensional reconstructions were established as a routine tool for analyzing volume data sets. These techniques opened totally new insights in the field of physical anthropology. Computed tomography became the ideal research tool to access the internal structures of various precious fossils without damaging or even touching them. Many of the most precious specimens from the species Autralopithecus (1.8-3.5 Myears), Homo heidelbergensis (200-600 kyears) or Homo neanderthalensis (40-100 kyears) were scanned during the last 5 years. Often the fossils are filled with a stone matrix or other materials. During the postprocessing routines highly advanced algorithms were used to remove virtually these incrustations. Thus it was possible to visualize the morphological structures that lie beneath the matrix. Some specimen were partially destroyed, so the missing parts were reconstructed on computer screen in order to get estimations of the brain volume and endocranial morphology, both major fields of interest in physical anthropology. Moreover the computerized form of the data allows new descriptions of morphologic structures by the means of 'geometric morphometrics'. Some of the results may change aspects and interpretations in human evolution. The introduction of new imaging and post processing techniques created a new field of research: Virtual Anthropology. PMID:10565508

Recheis, W; Weber, G W; Schäfer, K; Knapp, R; Seidler, H; zur Nedden, D

1999-08-01

469

Evaporation and instabilities of microscopic capillary bridges.  

PubMed

The formation and disappearance of liquid bridges between two surfaces can occur either through equilibrium or nonequilibrium processes. In the first instance, the bridge molecules are in thermodynamic equilibrium with the surrounding vapor medium. In the second, chemical potential gradients result in material transfer; mechanical instabilities, because of van der Waals force jumps on approach or a Rayleigh instability on rapid separation, may trigger irreversible film coalescence or bridge snapping. We have studied the growth and disappearance mechanisms of laterally microscopic liquid bridges of three hydrocarbon liquids in slit-like pores. At rapid slit-opening rates, the bridges rupture by means of a mechanical instability described by the Young-Laplace equation. Noncontinuum but apparently reversible behavior is observed when a bridge is held at nanoscopic surface separations H close to the thermodynamic equilibrium Kelvin length, 2r(K)costheta, where r(K) is the Kelvin radius and theta is the contact angle. During the course of slow evaporation (at H > 2r(K)costheta) and subsequent regrowth by capillary condensation (at H < 2r(K)costheta), the refractive index of the bridge may vary continuously and reversibly between that of the bulk liquid and vapor. The evaporation process becomes irreversible only at the very final stage of evaporation, when the refractive index of the fluid attains virtually that of the vapor. Measured refractive index profiles and the time-dependence of evaporating neck diameters also seem to differ from predictions based on a continuum picture of bridge evaporation far from the critical point. We discuss these findings in terms of the probable density profiles in evolving liquid bridges. PMID:12538868

Maeda, Nobuo; Israelachvili, Jacob N; Kohonen, Mika M

2003-01-21

470

Tele-nanorobotics using an atomic force microscope as a nanorobot and sensor  

Microsoft Academic Search

In this paper, a tele-nanorobotic system using an atomic force microscope (AFM) as the nanorobot and sensor has been proposed. Modeling and control of the AFM cantilever, and modeling of nanometer scale forces have been realized for telemanipulation applications. In addition to three-dimensional virtual reality visual feedback in the user interface, a 1 d.o.f. haptic device has been constructed for

Metin Sitti; Hideki Hashimoto

1998-01-01

471

Scanned probe microscope for biological applications  

NASA Astrophysics Data System (ADS)

In our biophysical laboratory has been developed a new scanned probe microscope (SPM) for biological application. The SPM allows to investigate a biological samples' surface by means of three different near field microscopes: scanning tunneling microscope (STM), atomic force microscope (AFM) and near field scanning optical microscope (NSOM). The SPM is very rigid and can be operated in ordinary laboratory without any vibration isolation. The scanning area of the microscope is about 10 by 10 micrometers. Some different biological objects were visualized by means of the SPM viz. bacteria (E. Coli, plague, cholera, staphylococcus), macromolecules (DNA, plague proteins) and phage (T2).

Baibyrin, Vil B.; Konnov, Nikolai P.; Shcherbakov, Anatolyi A.; Malakhaeva, Alina N.; Zadnova, Svetlana P.; Volkov, Yuri P.

1997-12-01

472

Evolution of the Taupo Volcanic Center, New Zealand: petrological and thermal constraints from the Omega dacite  

NASA Astrophysics Data System (ADS)

The 20 ka ~0.1 km3 Omega dacite, which erupted shortly after the 26.5 ka Oruanui super-eruption, compositionally stands out among Taupo Volcanic Zone (TVZ) magmas, which are overwhelmingly characterized by rhyolites (>90 % by volume). The previously reported presence of inherited zircons in this zircon-undersaturated magma has provided unequivocal evidence for the involvement of upper-crustal material in a 1-10 year timescale prior to the Omega eruption. However, whether this crustal involvement is characterized by wholesale, melting of preexisting crust or subordinate bulk assimilation into an already differentiated magma body remains unclear. To disentangle these processes, we describe the mineral chemistry of the major phases present in the Omega dacite and determine intensive parameters describing magma chamber conditions. Dominantly unimodal populations of plagioclase (An50-60), orthopyroxene (Mg# from 58 to 68), and clinopyroxene (Mg# from 65 to 73), along with coexisting equilibrium pairs of Fe-Ti oxides, constrain pre-eruptive temperatures to 850-950 °C, a pressure between ~3 and 7 kbars, and an oxygen fugacity of ~NNO. MELTS thermodynamic modeling suggests that this phase assemblage is in equilibrium with the bulk rock and glass compositions of the Omega dacite at these estimated P-T-fO2 pre-eruptive conditions. Combining these petrological observations with insights into conductive thermal models of magma-crust interactions, we argue that the Omega dacite more likely formed in the mid-to-lower crust via protracted processing through fractional crystallization coupled with some assimilation (AFC). Incorporation of crustal material is likely to have occurred at various stages, with the inherited zircons (and potentially parts of glomerocrysts) representing late and subordinate upper-crustal assimilants. This petrogenetic model is consistent with the presence of a differentiating crustal column, consisting of a polybaric fractional crystallization and assimilation history. On the basis of petrological, thermal, and geophysical considerations, upper-crustal reservoirs, which feed large-scale rhyolitic volcanism in the TVZ, most likely take the form of large, long-lived crystal mush zones. Following large eruptions, such as the Oruanui event, this mush is expected to crystallize significantly (up to 70-80 vol% crystals) due to syn-eruptive decompression. Hence, the Omega dacite, immediately post-dating the Oruanui event, potentially represents incoming deeper recharge of less-evolved magma that was able to penetrate the nearly solidified upper-crustal mush. Over the past 20,000 years, similar intermediate recharge magmas have incrementally reheated, reconstructed, and reactivated the upper-crustal mush zone, allowing a gradual return to rhyolitic volcanism at the Taupo Volcanic Center.

Gelman, Sarah E.; Deering, Chad D.; Gutierrez, Francisco J.; Bachmann, Olivier

2013-08-01

473

The Morne Aux Diables volcano, Dominica, Lesser Antilles: A stratigraphic and petrologic study.  

NASA Astrophysics Data System (ADS)

Morne Aux Diables is a topographically distinct stratovolcano located at the northernmost end of the island of Dominica, Lesser Antilles. In 2007, observations were conducted, and over 3,000 digital photographs were taken, of the well-exposed sea cliffs around Dominica. These observations, together with photogeological analysis of approximately 500 of these digital photographs of sea cliffs around the northern part of Dominica, have significantly improved our understanding of the geology of Morne aux Diables volcano, which previously had been based on scattered land exposures. The photographs were used to identify genetic packages of strata related to volcanogenic events and trace them around large sectors of the volcano's flanks. Based on these new studies, together with previous data, Morne aux Diables appears to have undergone two periods of activity, an older period dated between 2.1-1.5 Ma and a younger period dated at around 50,000 years B.P. Deposits associated with the older cone-forming activity are primarily composed of block and ash flows and surges associated with Pelean-style activity. These can be subdivided into a number of sequences based on the presence of paleosols. Domes associated with these eruptions are found both in the central vent area as well as around the flanks of the volcano. The upper deposits in the sea cliffs on the eastern, northern and western flanks are a thick sequence of surges that have been provisionally correlated with a well-exposed sequence of semi-vesicular block and ash flows and surge deposits at Morne a Louis on the west coast. The presence of these surge deposits at the top of the sea cliffs suggests that the older period of activity ended with open-crater Asama-style eruptions. Following an extensive quiescent period, renewed Pelean-style activity produced valley-fill block and ash flow and surge deposits, exposed on both the eastern and western sides of the volcano, together with associated domes (both central and parasitic). Petrographic studies show that Morne Aux Diables volcano is composed of andesites and dacites with a mineral assemblage of plagioclase+augite±hypersthene with minor hornblende and quartz. Geochemically both the older and younger volcanic rocks show trends, especially in terms of alkalis, that are slightly lower and cross- cut from those shown by the other centers on Dominica. These stratigraphic and petrologic studies will help further elucidate the volcanic history of Morne aux Diables and allow a petrologic-stratigraphic model of its formation.

Daly, G. L.; Smith, A. L.; Rheubottom, A. N.; Fryxell, J. E.

2008-12-01

474

Petrology and Geochemistry of the Northeast Seamounts of the Galapagos Platform  

NASA Astrophysics Data System (ADS)

One of the best locations to study hotspot-ridge interactions is the Northern Galápagos Province (NGP), the region that lies between the Galapagos Spreading Center (GSC) and the central portion of the Galapagos Archipelago. The Galapagos hotspot is currently located off-axis from the GSC but still has a profound influence on the ridge in terms of axial lava composition and ridge bathymetry. The NGP is characterized by an array of volcanic lineaments that are composed of seamounts and five small islands. The eastern edge of the NGP is defined by a group of at least five seamounts (the Northeast Seamounts), three of which were mapped and dredged in 1990 during Leg 2 of the PLUME expedition of the R/V Thomas Washington. We report petrological and geochemical data from the basalts recovered at six dredge sites. All basalts are tholeiitic with a general MORB-like composition, but with considerable variation within some individual dredge hauls and between seamounts. Previously published isotopic data are limited but 3He/4He ratios (Graham et al. 1993) and Sr-Nd-Pb isotopic data (Harpp and White 2000) are consistent with a depleted mantle source for all three seamounts. Based on geochemistry and petrological observations, the basalts can be divided into at least thirteen distinct groups. The bulk of the analyzed glass samples have compositions more than MORB with MgO content of 8-10% wt., although two of the groups are in the 6-7% range. In addition, the primitive lavas have high CaO and Al2O3 . The mineralogy ranges from aphyric for the more evolved lavas to olivine + plagioclase-phyric or plagioclase ultraphyric for the more primitive basalts. The plagioclase appear to be very calcic (up to An91) xenocrysts that are often hosting aluminous spinel (Al2O3 46-48% wt.) and primitive melt inclusions (Sinton et al., 1993). Initial trace element data show light rare earth (LREE)-depleted signatures, although several samples are slightly enriched in the LREE. Taken together, the data indicate that the seamounts were produced by variable extents of melting of a depleted mantle source. The mineralogy and geochemistry of the Northeastern Seamounts is similar to off-axis volcanoes, such as the Lamont Seamounts. We suggest that the Northeast Seamounts formed by passive rifting of young oceanic crust in which partial melts in the underlying mantle migrate in response to regional stresses. The primitive nature of the melts indicates the lack of a large magma chamber typical of those underlying mid-ocean ridges.

Sinton, C. W.; Harpp, K. S.; Christie, D. M.

2010-12-01

475

Evolution of the Taupo Volcanic Center, New Zealand: petrological and thermal constraints from the Omega dacite  

NASA Astrophysics Data System (ADS)

The 20 ka ~0.1 km3 Omega dacite, which erupted shortly after the 26.5 ka Oruanui super-eruption, compositionally stands out among Taupo Volcanic Zone (TVZ) magmas, which are overwhelmingly characterized by rhyolites (>90 % by volume). The previously reported presence of inherited zircons in this zircon-undersaturated magma has provided unequivocal evidence for the involvement of upper-crustal material in a 1-10 year timescale prior to the Omega eruption. However, whether this crustal involvement is characterized by wholesale, melting of preexisting crust or subordinate bulk assimilation into an already differentiated magma body remains unclear. To disentangle these processes, we describe the mineral chemistry of the major phases present in the Omega dacite and determine intensive parameters describing magma chamber conditions. Dominantly unimodal populations of plagioclase (An50-60), orthopyroxene (Mg# from 58 to 68), and clinopyroxene (Mg# from 65 to 73), along with coexisting equilibrium pairs of Fe-Ti oxides, constrain pre-eruptive temperatures to 850-950 °C, a pressure between ~3 and 7 kbars, and an oxygen fugacity of ~NNO. MELTS thermodynamic modeling suggests that this phase assemblage is in equilibrium with the bulk rock and glass compositions of the Omega dacite at these estimated P- T- fO2 pre-eruptive conditions. Combining these petrological observations with insights into conductive thermal models of magma-crust interactions, we argue that the Omega dacite more likely formed in the mid-to-lower crust via protracted processing through fractional crystallization coupled with some assimilation (AFC). Incorporation of crustal material is likely to have occurred at various stages, with the inherited zircons (and potentially parts of glomerocrysts) representing late and subordinate upper-crustal assimilants. This petrogenetic model is consistent with the presence of a differentiating crustal column, consisting of a polybaric fractional crystallization and assimilation history. On the basis of petrological, thermal, and geophysical considerations, upper-crustal reservoirs, which feed large-scale rhyolitic volcanism in the TVZ, most likely take the form of large, long-lived crystal mush zones. Following large eruptions, such as the Oruanui event, this mush is expected to crystallize significantly (up to 70-80 vol% crystals) due to syn-eruptive decompression. Hence, the Omega dacite, immediately post-dating the Oruanui event, potentially represents incoming deeper recharge of less-evolved magma that was able to penetrate the nearly solidified upper-crustal mush. Over the past 20,000 years, similar intermediate recharge magmas have incrementally reheated, reconstructed, and reactivated the upper-crustal mush zone, allowing a gradual return to rhyolitic volcanism at the Taupo Volcanic Center.

Gelman, Sarah E.; Deering, Chad D.; Gutierrez, Francisco J.; Bachmann, Olivier

2013-11-01