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Sample records for antonie van leeuwenhoek

  1. The microscopes of Antoni van Leeuwenhoek.

    PubMed

    van Zuylen, J

    1981-03-01

    The seventeenth-century Dutch microscopist, Antoni van Leeuwenhoek, was the first man to make a protracted study of microscopical objects, and, unlike his contemporary Robert Hooke, he viewed by transmitted light. Leeuwenhoek made over 500 of his own, curious, simple microscopes, but now only nine are known to exist. The exact nature of the lenses Leeuwenhoek made, has for long been a puzzle. The existing microscopes have now been examined in detail, and their optical characteristics measured and tabulated. It is proposed that the lens of highest magnification, x 266, was made using a special blown bubble technique.

  2. Antony van Leeuwenhoek's microscopes and other scientific instruments: new information from the Delft archives.

    PubMed

    Zuidervaart, Huib J; Anderson, Douglas

    2016-07-01

    This paper discusses the scientific instruments made and used by the microscopist Antony van Leeuwenhoek (1632-1723). The immediate cause of our study was the discovery of an overlooked document from the Delft archive: an inventory of the possessions that were left in 1745 after the death of Leeuwenhoek's daughter Maria. This list sums up which tools and scientific instruments Leeuwenhoek possessed at the end of his life, including his famous microscopes. This information, combined with the results of earlier historical research, gives us new insights about the way Leeuwenhoek began his lens grinding and how eventually he made his best lenses. It also teaches us more about Leeuwenhoek's work as a surveyor and a wine gauger. A further investigation of the 1747 sale of Leeuwenhoek's 531 single lens microscopes has not only led us to the identification of nearly all buyers, but also has provided us with some explanation about why only a dozen of this large number of microscopes has survived.

  3. The discovery of microorganisms by Robert Hooke and Antoni Van Leeuwenhoek, fellows of the Royal Society.

    PubMed

    Gest, Howard

    2004-05-01

    The existence of microscopic organisms was discovered during the period 1665-83 by two Fellows of The Royal Society, Robert Hooke and Antoni van Leeuwenhoek. In Micrographia (1665), Hooke presented the first published depiction of a microganism, the microfungus Mucor. Later, Leeuwenhoek observed and described microscopic protozoa and bacteria. These important revelations were made possible by the ingenuity of Hooke and Leeuwenhoek in fabricating and using simple microscopes that magnified objects from about 25-fold to 250-fold. After a lapse of more than 150 years, microscopy became the backbone of our understanding of the roles of microbes in the causation of infectious diseases and the recycling of chemical elements in the biosphere.

  4. [Little animals observed by Antony van Leeuwenhoek].

    PubMed

    Amako, Kazunobu

    2014-01-01

    Antony van Leeuwenhoek is the discoverer of bacteria and other microorganisms. However, his name is currently not as well-known as those of Louis Pasteur, Robert Koch or Shibasaburo Kitasato. Why not? To answer this question I read a book published in 1932 by Clifford Dobell, an English protozoologist, and found some answers. First, Leeuwenhoek was not a professional scientist in any university or scientific institute, but merely an average citizen in Delft, Holland, working as a merchant in his own shop, and later he also served as an office-holder in Delft city hall. Second, he made and invented his own microscopes but never made his work on microscopes and observation techniques widely known to the public. Accordingly, after his death, his excellent techniques for observing microorganisms were not handed down to the next generation and eventually became forgotten by the scientific community. Although he did not write any scientific paper, he did write about his observations in many letters addressed to the Royal Society of London. Dr. Dobell had translated most of them into English and included them in his book. I picked up and translated several of these letters into Japanese and have included them in this review to show how he described his observations and also what he thought about the presence of such small animals invisible to the naked eye. By reading this review I hope you will come to understand the efforts and abilities of a citizen in Delft about 340 years ago.

  5. Leeuwenhoek's Legacy

    ERIC Educational Resources Information Center

    Graham, R. P.

    1973-01-01

    This article takes note of the 250th anniversary of the dealth of Antony van Leeuwenhoek. Describes his life and contributions to science through his accurate and prolific examinations of the microscopic world. (JR)

  6. van Leeuwenhoek microscopes-where are they now?

    PubMed

    Robertson, Lesley A

    2015-05-01

    When Antonie van Leeuwenhoek died, he left over 500 simple microscopes, aalkijkers (an adaption of his microscope to allow the examination of blood circulation in the tails of small eels) and lenses, yet now there are only 10 microscopes with a claim to being authentic, one possible aalkijker and six lenses. He made microscopes with more than one lens, and possibly three forms of the aalkijker. This paper attempts to establish exactly what he left and trace the fate of some of the others using the earliest possible documents and publications. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  7. Still going strong: Leeuwenhoek at eighty.

    PubMed

    Anderson, Douglas

    2014-07-01

    At age 80, Antony van Leeuwenhoek was a world-famous scientist who came from a prosperous Delft family with a heritage of public service. He continued that tradition by serving in paid municipal offices. Self-taught, he began his scientific career in his 40s, when he began making hundreds of tiny single-lens microscopes. Pioneering the use of now-common microscopic techniques, he was the first human to see microbes and microscopic structures in animals, plants, and minerals. Over 50 years, he wrote only letters, more than 300 of them, and published half of them himself. More than a hundred were published in translation in the Royal Society's Philosophical Transactions. Today, Leeuwenhoek is considered in the lesser rank of scientists and is not well known outside of his homeland. Recent archival research in Delft has contributed new information about his life that helps to contextualize his science, but much remains to be learned.

  8. And then there were 12--distinguishing Van Leeuwenhoek microscopes from old or new copies.

    PubMed

    Robertson, Lesley A

    2015-07-01

    In the wake of announcements of the authentications of two previously unknown Van Leeuwenhoek microscopes in one month, this paper reviews the possibilities and potential pitfalls that might be involved in distinguishing 17th/18th century single-lensed microscopes from historical and modern copies. It is clear that a combination of characteristics must be considered, no single parameter will do. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  9. From Animaculum to single molecules: 300 years of the light microscope.

    PubMed

    Wollman, Adam J M; Nudd, Richard; Hedlund, Erik G; Leake, Mark C

    2015-04-01

    Although not laying claim to being the inventor of the light microscope, Antonj van Leeuwenhoek (1632-1723) was arguably the first person to bring this new technological wonder of the age properly to the attention of natural scientists interested in the study of living things (people we might now term 'biologists'). He was a Dutch draper with no formal scientific training. From using magnifying glasses to observe threads in cloth, he went on to develop over 500 simple single lens microscopes (Baker & Leeuwenhoek 1739 Phil. Trans. 41, 503-519. (doi:10.1098/rstl.1739.0085)) which he used to observe many different biological samples. He communicated his finding to the Royal Society in a series of letters (Leeuwenhoek 1800 The select works of Antony Van Leeuwenhoek, containing his microscopical discoveries in many of the works of nature, vol. 1) including the one republished in this edition of Open Biology. Our review here begins with the work of van Leeuwenhoek before summarizing the key developments over the last ca 300 years, which has seen the light microscope evolve from a simple single lens device of van Leeuwenhoek's day into an instrument capable of observing the dynamics of single biological molecules inside living cells, and to tracking every cell nucleus in the development of whole embryos and plants.

  10. From Animaculum to single molecules: 300 years of the light microscope

    PubMed Central

    Wollman, Adam J. M.; Nudd, Richard; Hedlund, Erik G.; Leake, Mark C.

    2015-01-01

    Although not laying claim to being the inventor of the light microscope, Antonj van Leeuwenhoek (1632–1723) was arguably the first person to bring this new technological wonder of the age properly to the attention of natural scientists interested in the study of living things (people we might now term ‘biologists’). He was a Dutch draper with no formal scientific training. From using magnifying glasses to observe threads in cloth, he went on to develop over 500 simple single lens microscopes (Baker & Leeuwenhoek 1739 Phil. Trans. 41, 503–519. (doi:10.1098/rstl.1739.0085)) which he used to observe many different biological samples. He communicated his finding to the Royal Society in a series of letters (Leeuwenhoek 1800 The select works of Antony Van Leeuwenhoek, containing his microscopical discoveries in many of the works of nature, vol. 1) including the one republished in this edition of Open Biology. Our review here begins with the work of van Leeuwenhoek before summarizing the key developments over the last ca 300 years, which has seen the light microscope evolve from a simple single lens device of van Leeuwenhoek's day into an instrument capable of observing the dynamics of single biological molecules inside living cells, and to tracking every cell nucleus in the development of whole embryos and plants. PMID:25924631

  11. The unseen world: reflections on Leeuwenhoek (1677) 'Concerning little animals'.

    PubMed

    Lane, Nick

    2015-04-19

    Leeuwenhoek's 1677 paper, the famous 'letter on the protozoa', gives the first detailed description of protists and bacteria living in a range of environments. The colloquial, diaristic style conceals the workings of a startlingly original experimental mind. Later scientists could not match the resolution and clarity of Leeuwenhoek's microscopes, so his discoveries were doubted or even dismissed over the following centuries, limiting their direct influence on the history of biology; but work in the twentieth century confirmed Leeuwenhoek's discovery of bacterial cells, with a resolution of less than 1 µm. Leeuwenhoek delighted most in the forms, interactions and behaviour of his little 'animalcules', which inhabited a previously unimagined microcosmos. In these reflections on the scientific reach of Leeuwenhoek's ideas and observations, I equate his questions with the preoccupations of our genomic era: what is the nature of Leeuwenhoek's animalcules, where do they come from, how do they relate to each other? Even with the powerful tools of modern biology, the answers are far from resolved-these questions still challenge our understanding of microbial evolution. This commentary was written to celebrate the 350th anniversary of the journal Philosophical Transactions of the Royal Society.

  12. The unseen world: reflections on Leeuwenhoek (1677) ‘Concerning little animals’

    PubMed Central

    Lane, Nick

    2015-01-01

    Leeuwenhoek's 1677 paper, the famous ‘letter on the protozoa’, gives the first detailed description of protists and bacteria living in a range of environments. The colloquial, diaristic style conceals the workings of a startlingly original experimental mind. Later scientists could not match the resolution and clarity of Leeuwenhoek's microscopes, so his discoveries were doubted or even dismissed over the following centuries, limiting their direct influence on the history of biology; but work in the twentieth century confirmed Leeuwenhoek's discovery of bacterial cells, with a resolution of less than 1 µm. Leeuwenhoek delighted most in the forms, interactions and behaviour of his little ‘animalcules', which inhabited a previously unimagined microcosmos. In these reflections on the scientific reach of Leeuwenhoek's ideas and observations, I equate his questions with the preoccupations of our genomic era: what is the nature of Leeuwenhoek's animalcules, where do they come from, how do they relate to each other? Even with the powerful tools of modern biology, the answers are far from resolved—these questions still challenge our understanding of microbial evolution. This commentary was written to celebrate the 350th anniversary of the journal Philosophical Transactions of the Royal Society. PMID:25750239

  13. Resurrecting Van Leeuwenhoek's rotifers: a reappraisal of the role of disaccharides in anhydrobiosis.

    PubMed Central

    Tunnacliffe, A; Lapinski, J

    2003-01-01

    In 1702, Van Leeuwenhoek was the first to describe the phenomenon of anhydrobiosis in a species of bdelloid rotifer, Philodina roseola. It is the purpose of this review to examine what has been learned since then about the extreme desiccation tolerance in rotifers and how this compares with our understanding of anhydrobiosis in other organisms. Remarkably, much of what is known today about the requirements for successful anhydrobiosis, and the degree of biostability conferred by the dry state, was already determined in principle by the time of Spallanzani in the late 18th century. Most modern research on anhydrobiosis has emphasized the importance of the non-reducing disaccharides trehalose and sucrose, one or other sugar being present at high concentrations during desiccation of anhydrobiotic nematodes, brine shrimp cysts, bakers' yeast, resurrection plants and plant seeds. These sugars are proposed to act as water replacement molecules, and as thermodynamic and kinetic stabilizers of biomolecules and membranes. In apparent contradiction of the prevailing models, recent experiments from our laboratory show that bdelloid rotifers undergo anhydrobiosis without producing trehalose or any analogous molecule. This has prompted us to critically re-examine the association of disaccharides with anhydrobiosis in the literature. Surprisingly, current hypotheses are based almost entirely on in vitro data: there is very limited information which is more than simply correlative in the literature on living systems. In many species, disaccharide accumulation occurs at approximately the same time as desiccation tolerance is acquired. However, several studies indicate that these sugars are not sufficient for anhydrobiosis; furthermore, there is no conclusive evidence, through mutagenesis or functional knockout experiments, for example, that sugars are necessary for anhydrobiosis. Indeed, some plant seeds and micro-organisms, like the rotifer, exhibit excellent desiccation

  14. [The proof of paternity. An andrological-forensic challenge in historical perspective].

    PubMed

    Albrecht, K; Schultheiss, D

    2004-10-01

    For centuries, difficulties have occurred in determining unresolved paternities. In addition to the modern standard methods, such as the examination of DNA or serological proof, expert opinion on fertility once played an important role. The andrological difference between incapability to fertilise and the inability to participate in sexual intercourse was also distinguished historically. Of special significance was the discovery of spermatozoa by the medical student Johan Ham in 1677 and their further investigation by Antoni van Leeuwenhoek.Recently, modern DNA methods have also been applied for historical investigations. Illustrious examples are the DNA analysis in the case of Kaspar Hauser of Ansbach and the dispute about Thomas Jefferson, President of the U.S., fathering a child by one of his slaves. In this discourse, a medicinal-forensic review of the development of expert opinion, illustrated with historical case studies, is given.

  15. Impact of New Camera Technologies on Discoveries in Cell Biology.

    PubMed

    Stuurman, Nico; Vale, Ronald D

    2016-08-01

    New technologies can make previously invisible phenomena visible. Nowhere is this more obvious than in the field of light microscopy. Beginning with the observation of "animalcules" by Antonie van Leeuwenhoek, when he figured out how to achieve high magnification by shaping lenses, microscopy has advanced to this day by a continued march of discoveries driven by technical innovations. Recent advances in single-molecule-based technologies have achieved unprecedented resolution, and were the basis of the Nobel prize in Chemistry in 2014. In this article, we focus on developments in camera technologies and associated image processing that have been a major driver of technical innovations in light microscopy. We describe five types of developments in camera technology: video-based analog contrast enhancement, charge-coupled devices (CCDs), intensified sensors, electron multiplying gain, and scientific complementary metal-oxide-semiconductor cameras, which, together, have had major impacts in light microscopy. © 2016 Marine Biological Laboratory.

  16. Interview with Antony John Kunnan on Language Assessment

    ERIC Educational Resources Information Center

    Nimehchisalem, Vahid

    2015-01-01

    Antony John Kunnan is a language assessment specialist. His research interests are fairness of tests and testing practice, assessment literacy, research methods and statistics, ethics and standards, and language assessment policy. His most recent publications include a four-volume edited collection of 140 chapters titled "The Companion to…

  17. Richard Bradley: a unified, living agent theory of the cause of infectious diseases of plants, animals, and humans in the first decades of the 18th century.

    PubMed

    Santer, Melvin

    2009-01-01

    During the years 1714 to 1721, Richard Bradley, who was later to become the first Professor of Botany at Cambridge University, proposed a unified, unique, living agent theory of the cause of infectious diseases of plants and animals and the plague of humans. Bradley's agents included microscopic organisms, revealed by the studies of Robert Hooke and Antony van Leeuwenhoek. His theory derived from his experimental studies of plants and their diseases and from microscopic observation of animalcules in different naturally occurring and artificial environments. He concluded that there was a microscopic world of "insects" that lived and reproduced under the appropriate conditions, and that infectious diseases of plants were caused by such "insects." Since there are structural and functional similarities between plants and animals, Bradley concluded that microscopic organisms caused human and animal infectious diseases as well. However, his living agent cause of infectious diseases was not accepted by the contemporary scientific society.

  18. Antoni Quintana-Mari (1907-1998): A Pioneer of the Use of History of Science in Science Education

    ERIC Educational Resources Information Center

    Roca-Rosell, Antoni; Grapi-Vilumara, Pere

    2010-01-01

    In the early 1930s, the young Antoni Quintana-Mari undertook some research on Antoni de Marti i Franques, one of the most prominent Catalan scientists of the Enlightenment. This scientist worked in Tarragona, where Quintana-Mari lived. Quintana-Mari learnt about Marti i Franques from Josep Estalella, his teacher of physics and chemistry at the…

  19. Language Assessment: Critical Issues--An Interview with Antony John Kunnan

    ERIC Educational Resources Information Center

    Jiang, Jinlin

    2017-01-01

    This interview provides a panoramic view of Antony's research interests, which includes his language-related experiences of early life, his study at UCLA, the PhD dissertation research he conducted under Lyle Bachman's supervision, and his idea of fairness. Given the specific context in which the interview was conducted, the interviewer approached…

  20. Historical microbiology, is it relevant in the 21st century?

    PubMed

    Robertson, Lesley A

    2015-05-01

    Facsimile microscopes have been used to examine the possibilities of van Leeuwenhoek microscopes with a range of magnifications, particularly to confirm that bacteria can be seen if the microscope is strong enough. The relevance of historical microbiology in education is also illustrated by adapting versions of van Leeuwenhoek's pepper water experiment and Beijerinck's use of bioluminescent bacteria as oxygen probes. These experiments can demonstrate fundamentals such as enrichment and isolation cultures, physiology and experimental planning as well as critical reading of published material. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  1. Environmental Project of I.E.S. Antoni Maura

    NASA Astrophysics Data System (ADS)

    Crespi Salom, Pere

    2010-05-01

    Environmental Project of I.E.S. Antoni Maura Author(s): Pere Crespí i Salom Teacher of Department of Biology and Geology and Environmental Coordinator (2009-2010) from I.E.S. Antoni Maura . Mallorca. Illes Balears. Spain Teachers participating in the project : Myriam Fuentes Milani, Olga Ballester Nebot, Antoni Salom Ruiz, Julio René Loayza Casanova, Puy Aguirre Rémirez, Yolanda Martínez Laserna, Jaume Puppo Lama, Carme Arrom , Dolors Aguiló Segura, Marga Ordinas Boter, Angel Fernàndez Albertí , Immaculada Suau López, Antònia Florit Torrandell, Isabel Mateu Arcos, Román Piña Valls i Pere Crespí Salom. Our institute takes part since 2004 in adapting environmentally the schools in the Balearics which consists of developing activities which aim is that both teachers and students acquire habits so as to apply to their ordinary lives though different participative commissions ( 10-15 teachers): 1st commission: recycling and reusing materials. Enough bins in the classrooms and floors: yellow for plastic, blue for paper, and green for the other. We tend to use recycled materials in different celebrations such as Carnival, Christmas, Saint Jordi and Environmental day. We also organise workshops for the teachers to develop afterwards with the students and nature of environmental exposures. 2nd commission: Scatter information ( MonMaura, Maurifull, Green window and website).Throughout different means we inform the teachers and students about all the school activities and where to consult.( www.iesantonimaura.net, Playful area , environmental project ). 3rd commission: Reusing text books.( there is a students service of borrowing books and giving them back at the end of the school year if the book is in good use.) 4th commission: Improving the school surroundings, the back garden and garden with native plants. Department of Biology and Geology is responsible for caring for an organic garden and in turn improve the center's garden with native plants within the

  2. Antoni Quintana-Marí (1907-1998): A Pioneer of the Use of History of Science in Science Education

    NASA Astrophysics Data System (ADS)

    Roca-Rosell, Antoni; Grapí-Vilumara, Pere

    2010-09-01

    In the early 1930s, the young Antoni Quintana-Marí undertook some research on Antoni de Martí i Franquès, one of the most prominent Catalan scientists of the Enlightenment. This scientist worked in Tarragona, where Quintana-Marí lived. Quintana-Marí learnt about Martí i Franquès from Josep Estalella, his teacher of physics and chemistry at the secondary school. It was while researching on Martí i Franquès that Quintana-Marí became a true historian of science. He subsequently collaborated with other Spanish and foreign historians of science in the early years of this discipline. Quintana-Marí never forgot that his passion for history of science had been aroused by his school teacher.

  3. Education under the Heel of Caesar: Reading UK Higher Education Reform through Shakespeare's "Antony and Cleopatra"

    ERIC Educational Resources Information Center

    Ward, Sophie

    2012-01-01

    UK higher education reform (BIS, ) has been presented as a common-sense movement towards efficiency. This article will argue that, in reality, the marketisation of higher education is a movement towards negative freedom, defined after Berlin (2007) as unrestricted choice. Using Shakespeare's "Antony and Cleopatra" as a means to explore…

  4. Using a Replica of Leeuwenhoek's Microscope to Teach the History of Science and to Motivate Students to Discover the Vision and the Contributions of the First Microscopists

    PubMed Central

    Loreto, Elgion L.S.; Rocha, João B.T.

    2009-01-01

    The history of science should be incorporated into science teaching as a means of improving learning and also to increase the students' understanding about the nature of science. In biology education, the history of microscopy deserves a special place. The discovery of this instrument not only opened a new and fantastic microworld but also led to the development of one unifying principle of biological sciences (i.e., cell theory). The microscopes of Leeuwenhoek and Hooke opened windows into the microworld of living organisms. In the present work, the knowledge of these themes was analyzed in a group of students beginning an undergraduate biology course. Our data suggest that the history of microscopy is poorly treated at the secondary school level. We propose a didactic activity using a replica of Leeuwenhoek's microscope made with Plexiglas and a lens obtained from a key chain laser pointer or from a broken CD drive. The proposed activity motivated students to learn about microscopy and helped them to appreciate scientific knowledge from a historical perspective. PMID:19952102

  5. Using a replica of Leeuwenhoek's microscope to teach the history of science and to motivate students to discover the vision and the contributions of the first microscopists.

    PubMed

    Sepel, Lenira M N; Loreto, Elgion L S; Rocha, João B T

    2009-01-01

    The history of science should be incorporated into science teaching as a means of improving learning and also to increase the students' understanding about the nature of science. In biology education, the history of microscopy deserves a special place. The discovery of this instrument not only opened a new and fantastic microworld but also led to the development of one unifying principle of biological sciences (i.e., cell theory). The microscopes of Leeuwenhoek and Hooke opened windows into the microworld of living organisms. In the present work, the knowledge of these themes was analyzed in a group of students beginning an undergraduate biology course. Our data suggest that the history of microscopy is poorly treated at the secondary school level. We propose a didactic activity using a replica of Leeuwenhoek's microscope made with Plexiglas and a lens obtained from a key chain laser pointer or from a broken CD drive. The proposed activity motivated students to learn about microscopy and helped them to appreciate scientific knowledge from a historical perspective.

  6. The early history of polyamine research.

    PubMed

    Bachrach, Uriel

    2010-07-01

    In 1678 Antonie van Leeuwenhoek identified crystalline substances in human semen. The structure of these crystals, named "spermine", was not elucidated by Rosenheim until 250 years later. Subsequently a triamine (spermidine) and a diamine (putrescine; 1,4-diaminobutane) were isolated from prokaryotic and eukaryotic systems. Soon it became apparent that polyamines can promote the growth of fastidious bacteria. Subsequently a group in Helsinki studied the accumulation of polyamines in regenerating rat liver, while Caldarera and his group studied polyamine synthesis in the developing chick embryo. These investigations led to metabolic studies. Ornithine decarboxylase was identified as a key enzyme in polyamine biosynthesis, while polyamine and diamine oxidations were studied by Mondovì. alpha-Diflouromethylornithine (DFMO) was synthesized by Merrell-Dow and became a potent inhibitor of ornithine decarboxylase. The findings of Russell that polyamines are excreted in the urine of cancer patients drew the attention of oncologists, who attempted the use new technologies for the detection of cancer and improving therapy. With the advance of molecular biology the structure of polyamine-biosynthetic enzymes was elaborated. Plants served as another important tool to study the physiological functions of polyamines. Bagni and his group at Bologna were pioneers in that field and for more than forty-six years set the foundation of a most interesting discipline. 2010 Elsevier Masson SAS. All rights reserved.

  7. INTRODUCTION TO ENVIRONMENTAL MICROBIOLOGY

    EPA Science Inventory

    Environmental microbiology is the study of those microorganisms which exist in natural or artificial environments. The origin of scientific research in this field rests in the observations of Antony van Leewenhoeck that were published in 1677(4). Van Leewenhoeck used a microsco...

  8. Advanced 3D Optical Microscopy in ENS Research.

    PubMed

    Vanden Berghe, Pieter

    2016-01-01

    Microscopic techniques are among the few approaches that have survived the test of time. Being invented half way the seventeenth century by Antonie van Leeuwenhoek and Robert Hooke, this technology is still essential in modern biomedical labs. Many microscopy techniques have been used in ENS research to guide researchers in their dissections and later to enable electrode recordings. Apart from this, microscopy has been instrumental in the identification of subpopulations of cells in the ENS, using a variety of staining methods. A significant step forward in the use of microscopy was the introduction of fluorescence approaches. Due to the fact that intense excitation light is now filtered away from the longer wavelength emission light, the contrast can be improved drastically, which helped to identify subpopulations of enteric neurons in a variety of species. Later functionalized fluorescent probes were used to measure and film activity in muscle and neuronal cells. Another important impetus to the use of microscopy was the discovery and isolation of the green fluorescent protein (GFP), as it gave rise to the development of many different color variants and functionalized constructs. Recent advances in microscopy are the result of a continuous search to enhance contrast between the item of interest and its background but also to improve resolving power to tell two small objects apart. In this chapter three different microscopy approaches will be discussed that can aid to improve our understanding of ENS function within the gut wall.

  9. Nonlocal van der Waals functionals: The case of rare-gas dimers and solids

    NASA Astrophysics Data System (ADS)

    Tran, Fabien; Hutter, Jürg

    2013-05-01

    Recently, the nonlocal van der Waals (vdW) density functionals [M. Dion, H. Rydberg, E. Schröder, D. C. Langreth, and B. I. Lundqvist, Phys. Rev. Lett. 92, 246401 (2004), 10.1103/PhysRevLett.92.246401] have attracted considerable attention due to their good performance for systems where weak interactions are important. Since the physics of dispersion is included in these functionals, they are usually more accurate and show less erratic behavior than the semilocal and hybrid methods. In this work, several variants of the vdW functionals have been tested on rare-gas dimers (from He2 to Kr2) and solids (Ne, Ar, and Kr) and their accuracy compared to standard semilocal approximations, supplemented or not by an atom-pairwise dispersion correction [S. Grimme, J. Antony, S. Ehrlich, and H. Krieg, J. Chem. Phys. 132, 154104 (2010), 10.1063/1.3382344]. An analysis of the results in terms of energy decomposition is also provided.

  10. Ludwik Antoni Birkenmajer and Curtis Wilson on the Origin of Nicholas Copernicus's Heliocentrism.

    PubMed

    Goddu, André

    2016-06-01

    What moved Copernicus to switch from the time-honored geocentric to a heliocentric setup for the planetary system? He himself did not explain this momentous move in any detail--his only comments about it suggest that Ptolemy's complete solution to the problem of nonuniform motion, the equant model, led him to propose. Earth's annual motion around the Sun. The most widely accepted accounts of the origin of Copernicus's theory dismiss or dispute any direct relation between the principle of uniform motion and the heliocentric theory. Two scholars, the Polish expert on Copernicus Ludwik Antoni Birkenmajer (1855-1929) and the American historian of astronomy Curtis Wilson (1921-2012), constructed detailed arguments about how Copernicus's rejection of Ptolemy's solution led him to his theory. The principal aim of this essay is to reintroduce Birkenmajer's and Wilson's voices to the discussion of the origin of Copernicus's heliocentrism.

  11. Cell motility under the microscope: Vorsprung durch Technik.

    PubMed

    Dunn, Graham A; Jones, Gareth E

    2004-08-01

    The fashion today is to disparage technology-led research but our view is that cell biologists, in particular, should be proud of their 'progress through technology'. The 'cell theory' itself, arguably the oldest cornerstone in the theoretical foundations of biology, emerged because Hooke, van Leeuwenhoek and others had, more than a century earlier, pioneered the enabling technology--the microscope. We develop this theme with reference to our own field of research: the locomotion of cultured tissue cells.

  12. Dermatography (Medical Tattooing) for Scars and Skin Grafts in Head and Neck Patients to Improve Appearance and Quality of Life.

    PubMed

    Drost, Brigitte H; van de Langenberg, Rick; Manusama, Olivia R; Janssens, A Soe; Sikorska, Karolina; Zuur, C Lot; Klop, Willem M C; Lohuis, Peter J F M

    2017-01-01

    Dermatography (medical tattooing) is often overlooked as an adjuvant procedure to improve color mismatch in the head and neck area, and its effect on patient satisfaction and quality of life has not been evaluated, to our knowledge. To analyze the effect of dermatography on the subjective perception of the appearance of scars and skin grafts and the quality of life in head and neck patients. Case series of patients undergoing dermatography at the Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam, between July 1, 2007, and April 1, 2015. Participants were invited to respond to 2 questionnaires measuring their scar or graft appearance and their quality of life before and after dermatography as an adjuvant treatment for benign or malignant head and neck tumors. Use of dermatography. Two questionnaires evaluating a visual analog scale score (range, 0-10) and multiple questions on a 5-point scale focusing on satisfaction with the appearance and the quality of life. Among 76 patients, 56 (74%) were included in the study. The mean (SD) age of the study cohort was 56.5 (16.0) years, and 42 (75%) were female. The mean improvement in scar or skin graft perception on the visual analog scale of the modified Utrecht Questionnaire for Outcome Assessment in Aesthetic Rhinoplasty before and after dermatography was 4 points. On the modified Patient Scar Assessment Questionnaire, uniform improvement of approximately 1 point across 9 questions was observed. The answers to all patient satisfaction and quality-of-life questions on both questionnaires improved significantly after dermatography. Dermatography is an effectual adjuvant procedure to improve the subjective perception of scar and skin graft appearance and the quality of life in head and neck patients. 4.

  13. Diversity of Tn1546 in vanA-positive Enterococcus faecium clinical isolates with VanA, VanB, and VanD phenotypes and susceptibility to vancomycin.

    PubMed

    Cha, J O; Yoo, J I; Kim, H K; Kim, H S; Yoo, J S; Lee, Y S; Jung, Y H

    2013-10-01

    To investigate diversity in the vanA cluster in Enterococcus faecium isolates from nontertiary hospitals. We identified 43 vanA-positive Ent. faecium isolates, including two vancomycin-susceptible isolates, from hospitals between 2003 and 2006. Of these isolates, >85% were resistant to ampicillin, erythromycin and ciprofloxacin. The vanA cluster was classified into six types using overlapping PCR, but the prototype transposon Tn1546 was not found. Most vanA-positive vancomycin-resistant Enterococcus (VRE) carried IS1216V and belonged to Type III (58·1%) or Type II (20·9%). vanY, vanZ and IS1216V were observed in the left and right ends of Type III with long-range PCR. IS1216V was also observed within vanS and vanX in the two vancomycin-susceptible isolates and in two vancomycin-resistant isolates. No VRE isolates with VanB and VanD phenotypes contained point mutations in vanS, unlike in previous reports. Sequence types (STs) of all isolates belonged to clonal complex 17, and ST78 was predominant. Insertion sequences, especially IS1216V, cause structural variation in the vanA cluster. We report the first observation of vanY and vanZ at the left end of Tn1546 in clinical isolates. This is the first report of the frequency of vancomycin resistance and diversity of Tn1546 in vanA-positive Ent. faecium isolates from nontertiary hospitals. © 2013 The Society for Applied Microbiology.

  14. Presence of the vancomycin resistance gene cluster vanC1, vanXYc, and vanT in Enterococcus casseliflavus.

    PubMed

    Hölzel, Christina; Bauer, Johann; Stegherr, Eva-Maria; Schwaiger, Karin

    2014-04-01

    The three chromosomally located clustered genes vanC1, vanXYc, and vanT confer intrinsic resistance to vancomycin and are used for species identification of Enterococcus gallinarum. In this study, 28 strains belonging to the E. gallinarum/casseliflavus group isolated from cloacal swabs from laying hens were screened for the presence of vanC1. As confirmed by species-specific multiplex PCR, 11 vanC1-positive strains were identified as E. gallinarum. Surprisingly, one yellow pigmented strain, verified as E. casseliflavus by species-specific multiplex PCR, was also vanC1 positive; vanXYc and vanT were additionally detectable in this strain. To our knowledge, this is the first report of vanC1, vanXYc, and vanT in E. casseliflavus. The minimum inhibitory concentration of vancomycin was 4 mg/L. Real-time reverse transcription-PCR revealed that none of the clustered genes was expressed in this strain. Even if the genes seem not to be active, there is a certain risk that they will be transferred to other bacteria where they might be functionally expressed. Therefore, it may be advisable to expand the search for vanC1, vanXYc, and vanT from E. gallinarum to other (enterococcal) species. This study confirms that enterococci live up to their name as being reservoir bacteria and should therefore always be closely monitored.

  15. Antoni marian gabryszewski as a pioneer of orthopaedics and rehabilitation in poland.

    PubMed

    Jandziś, Sławomir

    2014-01-01

    This article describes the work of Dr. Antoni Marian Gabryszewski, orthopaedic surgeon, associate professor at Lvov University, towards the development of orthopaedics and rehabilitation in Poland before World War I. It is based on archival materials, publications in medical journals and articles from the daily press of that time. The author presents little-known facts concerning Dr. Gabryszewski's occupational and academic activity and his work at the Surgery Dept. of Lvov University as well as his habilitation dissertation, regarded as the first attempt to position orthopaedics as distinct from surgery in Poland. The article also describes his long-term work at the private Orthopaedic Facility established in 1898 in Lvov which later incorporated the Zander Institute in 1908. The Zander Institute was the first in Galicia to offer exercise machines designed by Dr. Gustav Zander, imported from Stockholm and enjoying an extraordinary popularity in the world. Dr. Gabryszewski's practice as a spa doctor, which he pursued in Iwonicz Zdrój in the summer months, is also presented. Dr. A. Gabryszewski introduced comprehensive rehabilitation to the treatment of orthopaedic patients both at the Surgery Dept. of Lvov University and at his Orthopaedic Facility. He used therapeutic gymnastics (particularly mechanotherapy), therapeutic massage, physical therapy and orthopaedic aids. Analysis of the source materials leads to unequivocal conclusions attesting to Dr. A. Gabryszewski's pioneering role and significant contribution to the development of orthopaedics and rehabilitation in Poland.

  16. Hydrodynamics of the VanA-type VanS histidine kinase: an extended solution conformation and first evidence for interactions with vancomycin

    PubMed Central

    Phillips-Jones, Mary K.; Channell, Guy; Kelsall, Claire J.; Hughes, Charlotte S.; Ashcroft, Alison E.; Patching, Simon G.; Dinu, Vlad; Gillis, Richard B.; Adams, Gary G.; Harding, Stephen E.

    2017-01-01

    VanA-type resistance to glycopeptide antibiotics in clinical enterococci is regulated by the VanSARA two-component signal transduction system. The nature of the molecular ligand that is recognised by the VanSA sensory component has not hitherto been identified. Here we employ purified, intact and active VanSA membrane protein (henceforth referred to as VanS) in analytical ultracentrifugation experiments to study VanS oligomeric state and conformation in the absence and presence of vancomycin. A combination of sedimentation velocity and sedimentation equilibrium in the analytical ultracentrifuge (SEDFIT, SEDFIT-MSTAR and MULTISIG analysis) showed that VanS in the absence of the ligand is almost entirely monomeric (molar mass M = 45.7 kDa) in dilute aqueous solution with a trace amount of high molar mass material (M ~ 200 kDa). The sedimentation coefficient s suggests the monomer adopts an extended conformation in aqueous solution with an equivalent aspect ratio of ~(12 ± 2). In the presence of vancomycin over a 33% increase in the sedimentation coefficient is observed with the appearance of additional higher s components, demonstrating an interaction, an observation consistent with our circular dichroism measurements. The two possible causes of this increase in s – either a ligand induced dimerization and/or compaction of the monomer are considered. PMID:28397853

  17. Co-colonization of vanA and vanB Enterococcus faecium of clonal complex 17 in a patient with bacteremia due to vanA E. faecium.

    PubMed

    Seol, Chang Ahn; Park, Jeong Su; Sung, Heungsup; Kim, Mi-Na

    2014-06-01

    A 53-year-old Vietnamese man with liver cirrhosis was transferred from a Vietnamese hospital to our tertiary care hospital in Korea in order to undergo a liver transplantation. Bacteremia due to vanA Enterococcus faecium was diagnosed, and stool surveillance cultures for vancomycin-resistant enterococci (VRE) were positive for both vanA and vanB E. faecium. Pulsed-field gel electrophoresis analysis revealed that the 2 vanA VRE isolates from the blood and stool were clonal, but the vanB VRE was unrelated to the vanA VRE. vanA and vanB VRE were ST64 and ST18, single-allele variations of clonal complex 17, respectively. This is the first case report of vanA VRE bacteremia in a Vietnamese patient and demonstrates the reemergence of vanB VRE since a single outbreak occurred 15years ago in Korea. The reemergence of vanB VRE emphasizes the importance of VRE genotyping to prevent the spread of new VRE strains. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Long-term prognosis of young breast cancer patients (≤40 years) who did not receive adjuvant systemic treatment: protocol for the PARADIGM initiative cohort study

    PubMed Central

    Dackus, Gwen MHE; ter Hoeve, Natalie D; Opdam, Mark; Vreuls, Willem; Varga, Zsuzsanna; Koop, Esther; Willems, Stefan M; Van Deurzen, Carolien HM; Groen, Emilie J; Cordoba, Alicia; Bart, Jos; Mooyaart, Antien L; van den Tweel, Jan G; Zolota, Vicky; Wesseling, Jelle; Sapino, Anna; Chmielik, Ewa; Ryska, Ales; Amant, Frederic; Broeks, Annegien; Kerkhoven, Ron; Stathonikos, Nikolas; Veta, Mitko; Voogd, Adri; Jozwiak, Katarzyna; Hauptmann, Michael; Hoogstraat, Marlous; Schmidt, Marjanka K; Sonke, Gabe; van der Wall, Elsken; Siesling, Sabine; van Diest, Paul J; Linn, Sabine C

    2017-01-01

    Institute - Antoni van Leeuwenhoek hospital, waiving individual patient consent. All data and material used are stored in a coded way. Study results will be presented at international (breast cancer) conferences and published in peer-reviewed, open-access journals. PMID:29138205

  19. The comeback of hand drawing in modern life sciences.

    PubMed

    Chabrier, Renaud; Janke, Carsten

    2018-03-01

    Scientific manuscripts are full of images. Since the birth of the life sciences, these images were in a form of hand drawings, with great examples from da Vinci, Hooke, van Leeuwenhoek, Remak, Buffon, Bovery, Darwin, Huxley, Haeckel and Gray's Anatomy to name a few. However, in the course of the past century, photographs and simplified schematics have gradually taken over as a way of illustrating scientific data and concepts, assuming that these are 'accurate' representations of the truth. Here, we argue for the importance of reviving the art of scientific drawings as a way of effectively communicating complex scientific ideas to both specialists and the general public.

  20. Amino acid substitutions in the VanS sensor of the VanA-type vancomycin-resistant Enterococcus strains result in high-level vancomycin resistance and low-level teicoplanin resistance.

    PubMed

    Hashimoto, Y; Tanimoto, K; Ozawa, Y; Murata, T; Ike, Y

    2000-04-15

    The vancomycin-resistant enterococci GV1, GV2 and GV3, which were isolated from droppings from broiler farms in Japan have been characterized as VanA-type VRE, which express high-level vancomycin resistance (256 or 512 microg ml(-1), MIC) and low-level teicoplanin resistance (1 or 2 microg ml(-1), MIC). The vancomycin resistances were encoded on plasmids. The vancomycin resistance conjugative plasmid pMG2 was isolated from the GV2 strain. The VanA determinant of pMG2 showed the same genetic organization as that of the VanA genes encoded on the representative transposon Tn1546, which comprises vanRSHAXYZ. The nucleotide sequences of all the genes, except the gene related to the vanS gene on Tn1546, were completely identical to the genes encoded on Tn1546. Three amino acid substitutions in the N-terminal region of the deduced VanS were detected in the nucleotide sequence of vanS encoded on pMG2. There were also three amino acid substitutions in the vanS gene of the GV1 and GV3 strains in the same positions as in the vanS gene of pMG2. Vancomycin induced the increased teicoplanin resistance in these strains.

  1. [From the Auschwitz Syndrome to a Psyche Model--Life and Work of the Polish Psychiatrist Antoni Kepinski (1918-1972)].

    PubMed

    Schochow, Maximilian; Willer, Manuel; Steger, Florian

    2016-01-01

    Life and work of the Polish psychiatrist Antoni Kepinski (1918 - 1972) are barely known today, although his writings about the Auschwitz syndrome have had an impact all over the world. We present his biography and work. Compilation and evaluation of literature about Kepinski's work and historical-critical analysis of his key texts. Kepinski's work about the Auschwitz syndrome formed the basis for his understanding of the psyche and his theory on information metabolism. Kepinski posited that the mind processes outside stimuli based on its own set of values and that it determines the subject's actions. In doing so, it affects its environment. If these interactions are disrupted, pathological disorders might result. The therapist should consequently empower the patient to get in touch with his own value-system. Kepinskis work serves as a foundation for research on disease patterns that are known today as post-traumatic stress disorder (PTSD). His theory on information metabolism is essential for the current treatment of patients. It is therefore important to further explore his work and adjust it to the requirements of medical practice. © Georg Thieme Verlag KG Stuttgart · New York.

  2. 19 CFR 10.41a - Lift vans, cargo vans, shipping tanks, skids, pallets, and similar instruments of international...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 19 Customs Duties 1 2011-04-01 2011-04-01 false Lift vans, cargo vans, shipping tanks, skids... Traffic § 10.41a Lift vans, cargo vans, shipping tanks, skids, pallets, and similar instruments of international traffic; repair components. (a)(1) Lift vans, cargo vans, shipping tanks, skids, pallets, caul...

  3. 19 CFR 10.41a - Lift vans, cargo vans, shipping tanks, skids, pallets, and similar instruments of international...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 19 Customs Duties 1 2010-04-01 2010-04-01 false Lift vans, cargo vans, shipping tanks, skids... Traffic § 10.41a Lift vans, cargo vans, shipping tanks, skids, pallets, and similar instruments of international traffic; repair components. (a)(1) Lift vans, cargo vans, shipping tanks, skids, pallets, caul...

  4. Defending commercial surrogate motherhood against Van Niekerk and Van Zyl.

    PubMed Central

    McLachlan, H V

    1997-01-01

    The arguments of Van Niekerk and Van Zyl that, on the grounds that it involves an inappropriate commodification and alienation of women's labour, commercial surrogate motherhood (CSM) is morally suspect are discussed and considered to be defective. In addition, doubt is cast on the notion that CSM should be illegal. PMID:9451602

  5. Space Van system update

    NASA Astrophysics Data System (ADS)

    Cormier, Len

    1992-07-01

    The Space Van is a proposed commercial launch vehicle that is designed to carry 1150 kg to a space-station orbit for a price of $1,900,000 per flight in 1992 dollars. This price includes return on preoperational investment. Recurring costs are expected to be about $840,000 per flight. The Space Van is a fully reusable, assisted-single-stage-to orbit system. The most innovative new feature of the Space Van system is the assist-stage concept. The assist stage uses only airbreathing engines for vertical takeoff and vertical landing in the horizontal attitude and for launching the rocket-powered orbiter stage at mach 0.8 and an altitude of about 12 km. The primary version of the orbiter is designed for cargo-only without a crew. However, a passenger version of the Space Van should be able to carry a crew of two plus six passengers to a space-station orbit. Since the Space Van is nearly single-stage, performance to polar orbit drops off significantly. The cargo version should be capable of carrying 350 kg to a 400-km polar orbit. In the passenger version, the Space Van should be able to carry two crew members - or one crew member plus a passenger.

  6. Mentale Inzetbaarheid van Teams: Ontwikkeling van een Moden van Teamfunctioneren als Module voor SCOPE (Mental Readiness of Teams - Development of a Team Model as Module for SCOPE)

    DTIC Science & Technology

    2007-04-01

    inzetbaarheid van teams: ontwikkeling van een model van teamfunctioneren als module voor SCOPE Datumn april 2007 Auteur (s) R. de B~ruin C’. Vervvijs A.J...Datum april 2007 Programmaleider Projectleider Auteur (s) dr. W.A. Lotens, TNO Defensie en A.]. van Vijet, TNO Defensie en R. de Bruin Veiligheid...Deelnemers verwachten wel, in lijn met de theorie , dat een lage cohesie samenhangt met een lage effectiviteit. Een hoge cohesie, daarentegen, zou

  7. Mobile Telemetry Van Remote Control Upgrade

    DTIC Science & Technology

    2012-05-17

    Advantages of Remote Control System Upgrade • Summary Overview • Remote control of Telemetry Mobile Ground Support ( TMGS ) Van proposed to allow...NWC) personnel provided valuable data for full-function remote control of telemetry tracking vans Background • TMGS Vans support Flight Test...control capability from main TM site at Building 5790 currently allows support via TMGS Van at nearby C- 15 Site, Plant 42 in Palmdale, and as far

  8. Members of the Genera Paenibacillus and Rhodococcus Harbor Genes Homologous to Enterococcal Glycopeptide Resistance Genes vanA and vanB

    PubMed Central

    Guardabassi, L.; Christensen, H.; Hasman, H.; Dalsgaard, A.

    2004-01-01

    Genes homologous to enterococcal glycopeptide resistance genes vanA and vanB were found in glycopeptide-resistant Paenibacillus and Rhodococcus strains from soil. The putative d-Ala:d-Lac ligase genes in Paenibacillus thiaminolyticus PT-2B1 and Paenibacillus apiarius PA-B2B were closely related to vanA (92 and 87%) and flanked by genes homologous to vanH and vanX in vanA operons. PMID:15561881

  9. Members of the genera Paenibacillus and Rhodococcus harbor genes homologous to enterococcal glycopeptide resistance genes vanA and vanB.

    PubMed

    Guardabassi, L; Christensen, H; Hasman, H; Dalsgaard, A

    2004-12-01

    Genes homologous to enterococcal glycopeptide resistance genes vanA and vanB were found in glycopeptide-resistant Paenibacillus and Rhodococcus strains from soil. The putative D-Ala:D-Lac ligase genes in Paenibacillus thiaminolyticus PT-2B1 and Paenibacillus apiarius PA-B2B were closely related to vanA (92 and 87%) and flanked by genes homologous to vanH and vanX in vanA operons.

  10. 19 CFR 10.41a - Lift vans, cargo vans, shipping tanks, skids, pallets, and similar instruments of international...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... for inspection by Customs officials upon reasonable notice. (3) If the container does not exit the U.S... 19 Customs Duties 1 2014-04-01 2014-04-01 false Lift vans, cargo vans, shipping tanks, skids... Traffic § 10.41a Lift vans, cargo vans, shipping tanks, skids, pallets, and similar instruments of...

  11. 19 CFR 10.41a - Lift vans, cargo vans, shipping tanks, skids, pallets, and similar instruments of international...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... for inspection by Customs officials upon reasonable notice. (3) If the container does not exit the U.S... 19 Customs Duties 1 2012-04-01 2012-04-01 false Lift vans, cargo vans, shipping tanks, skids... Traffic § 10.41a Lift vans, cargo vans, shipping tanks, skids, pallets, and similar instruments of...

  12. 19 CFR 10.41a - Lift vans, cargo vans, shipping tanks, skids, pallets, and similar instruments of international...

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... for inspection by Customs officials upon reasonable notice. (3) If the container does not exit the U.S... 19 Customs Duties 1 2013-04-01 2013-04-01 false Lift vans, cargo vans, shipping tanks, skids... Traffic § 10.41a Lift vans, cargo vans, shipping tanks, skids, pallets, and similar instruments of...

  13. A unique Austin Chalk reservoir, Van field, Van Zandt County, Texas

    SciTech Connect

    Lowe, J.T.

    1990-09-01

    Significant shallow oil production from the Austin Chalk was established in the Van field, Van Zandt County, in East Texas in the late 1980s. The Van field structure is a complexly faulted domal anticline created by salt intrusion. The Woodbine sands, which underlie the Austin Chalk, have been and continue to be the predominant reservoir rocks in the field. Evidence indicates that faults provided vertical conduits for migration of Woodbine oil into the Austin Chalk where it was trapped along the structural crest. The most prolific Austin Chalk production is on the upthrown side of the main field fault, asmore » is the Woodbine. The Austin Chalk is a soft, white to light gray limestone composed mostly of coccoliths with some pelecypods. Unlike the Austin Chalk in the Giddings and Pearsall fields, the chalk at Van was not as deeply buried and therefore did not become brittle and susceptible to tensional or cryptic fracturing. The shallow burial in the Van field was also important in that it allowed the chalk to retain primary microporosity. The production comes entirely from this primary porosity. In addition to the structural position and underlying oil source from the Woodbine, the depositional environment and associated lithofacies are also keys to the reservoir quality in the Van field as demonstrated by cores from the upthrown and downthrown (less productive) sides of the main field fault. It appears that at the time of Austin Chalk deposition, the main field fault was active and caused the upthrown side to be a structural high and a more agreeable environment for benthonic organisms such as pelecypods and worms. The resulting bioturbation enhanced the reservoir's permeability enough to allow migration and entrapment of the oil. Future success in exploration for analogous Austin Chalk reservoirs will require the combination of a favorable environment of deposition, a nearby Woodbine oil source, and a faulted trap that will provide the conduit for migration.« less

  14. Stirling Powered Van Progam overview

    NASA Technical Reports Server (NTRS)

    Shaltens, R. K.

    1986-01-01

    The Stirling Powered Van Program (SPVP) is a multiyear, multiphase program to evaluate the automotive Stirling engine (ASE) in Air Force vans under realistic conditions. The objective of the SPVP is to transfer to manufacturer and end user(s) (i.e., on the path to commercialization) the second-generation Mod 2 ASE upon completion of the Automotive Stirling Engine Program in 1987. In order to meet this objective, the SPVP must establish Stirling performance, integrity, reliability, durability and maintainability. The ASE program background leading to the van program is reviewed and plans for evaluating the kinematic Stirling engine in Air Force vans examined. Also discussed are the NASA technology transfers to industry that have been accomplished and those which are currently being developed.

  15. vanC Cluster of Vancomycin-Resistant Enterococcus gallinarum BM4174

    PubMed Central

    Arias, Cesar A.; Courvalin, Patrice; Reynolds, Peter E.

    2000-01-01

    Glycopeptide-resistant enterococci of the VanC type synthesize UDP-muramyl-pentapeptide[d-Ser] for cell wall assembly and prevent synthesis of peptidoglycan precursors ending in d-Ala. The vanC cluster of Enterococcus gallinarum BM4174 consists of five genes: vanC-1, vanXYC, vanT, vanRC, and vanSC. Three genes are sufficient for resistance: vanC-1 encodes a ligase that synthesizes the dipeptide d-Ala-d-Ser for addition to UDP-MurNAc-tripeptide, vanXYC encodes a d,d-dipeptidase–carboxypeptidase that hydrolyzes d-Ala-d-Ala and removes d-Ala from UDP-MurNAc-pentapeptide[d-Ala], and vanT encodes a membrane-bound serine racemase that provides d-Ser for the synthetic pathway. The three genes are clustered: the start codons of vanXYC and vanT overlap the termination codons of vanC-1 and vanXYC, respectively. Two genes which encode proteins with homology to the VanS-VanR two-component regulatory system were present downstream from the resistance genes. The predicted amino acid sequence of VanRC exhibited 50% identity to VanR and 33% identity to VanRB. VanSC had 40% identity to VanS over a region of 308 amino acids and 24% identity to VanSB over a region of 285 amino acids. All residues with important functions in response regulators and histidine kinases were conserved in VanRC and VanSC, respectively. Induction experiments based on the determination of d,d-carboxypeptidase activity in cytoplasmic extracts confirmed that the genes were expressed constitutively. Using a promoter-probing vector, regions upstream from the resistance and regulatory genes were identified that have promoter activity. PMID:10817725

  16. Long-term prognosis of young breast cancer patients (≤40 years) who did not receive adjuvant systemic treatment: protocol for the PARADIGM initiative cohort study.

    PubMed

    Dackus, Gwen Mhe; Ter Hoeve, Natalie D; Opdam, Mark; Vreuls, Willem; Varga, Zsuzsanna; Koop, Esther; Willems, Stefan M; Van Deurzen, Carolien Hm; Groen, Emilie J; Cordoba, Alicia; Bart, Jos; Mooyaart, Antien L; van den Tweel, Jan G; Zolota, Vicky; Wesseling, Jelle; Sapino, Anna; Chmielik, Ewa; Ryska, Ales; Amant, Frederic; Broeks, Annegien; Kerkhoven, Ron; Stathonikos, Nikolas; Veta, Mitko; Voogd, Adri; Jozwiak, Katarzyna; Hauptmann, Michael; Hoogstraat, Marlous; Schmidt, Marjanka K; Sonke, Gabe; van der Wall, Elsken; Siesling, Sabine; van Diest, Paul J; Linn, Sabine C

    2017-11-14

    Currently used tools for breast cancer prognostication and prediction may not adequately reflect a young patient's prognosis or likely treatment benefit because they were not adequately validated in young patients. Since breast cancers diagnosed at a young age are considered prognostically unfavourable, many treatment guidelines recommend adjuvant systemic treatment for all young patients. Patients cured by locoregional treatment alone are, therefore, overtreated. Lack of prognosticators for young breast cancer patients represents an unmet medical need and has led to the initiation of the PAtients with bReAst cancer DIaGnosed preMenopausally (PARADIGM) initiative. Our aim is to reduce overtreatment of women diagnosed with breast cancer aged ≤ 40 years. All young, adjuvant systemic treatment naive breast cancer patients, who had no prior malignancy and were diagnosed between 1989 and 2000, were identified using the population based Netherlands Cancer Registry (n=3525). Archival tumour tissues were retrieved through linkage with the Dutch nationwide pathology registry. Tissue slides will be digitalised and placed on an online image database platform for clinicopathological revision by an international team of breast pathologists. Immunohistochemical subtype will be assessed using tissue microarrays. Tumour RNA will be isolated and subjected to next-generation sequencing. Differences in gene expression found between patients with a favourable and those with a less favourable prognosis will be used to establish a prognostic classifier, using the triple negative patients as proof of principle. Observational data from the Netherlands Cancer Registry and left over archival patient material are used. Therefore, the Dutch law on Research Involving Human Subjects Act (WMO) is not applicable. The PARADIGM study received a 'non-WMO' declaration from the Medical Ethics Committee of the Netherlands Cancer Institute - Antoni van Leeuwenhoek hospital, waiving individual patient

  17. Treatment of Basal Cell Carcinoma Using a One-Stop-Shop With Reflectance Confocal Microscopy: Study Design and Protocol of a Randomized Controlled Multicenter Trial.

    PubMed

    Kadouch, Daniel J; Wolkerstorfer, Albert; Elshot, Yannick; Zupan-Kajcovski, Biljana; Crijns, Marianne B; Starink, Markus V; Bekkenk, Marcel W; van der Wal, Allard C; Spuls, Phyllis I; de Rie, Menno A

    2015-09-10

    Basal cell carcinoma (BCC) is the most common cancer diagnosed in white populations worldwide. The rising incidence of BCC is becoming a major worldwide public health problem. Therefore, there is a need for more efficient management. The aim of this research is to assess the efficacy and safety of a one-stop-shop (OSS) concept, using real-time in vivo reflectance confocal microscopy (RCM) (Vivascope 1500; Lucid Technologies, Henrietta, NY, USA) as a diagnostic tool, prior to surgical management of new primary BCCs. This is a prospective non-inferiority multi-center RCT designed to compare the "OSS concept using RCM" to current standards of care in diagnosing and treating clinically suspected BCC. Patients ≥ 18 years attending our outpatient clinic at the Department of Dermatology, Academic Medical Center, University of Amsterdam, and the Department of Dermatology, the Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital (Amsterdam, The Netherlands) with a clinically suspected new primary BCC lesion will be considered for enrollment using predefined inclusion and exclusion criteria, and will be randomly allocated to the experimental or control group. The main outcome parameter is the assessment of incomplete surgical excision margins on the final pathology report of confirmed BCC lesions (either by punch biopsy or RCM imaging). Other outcome measures include diagnostic accuracy (sensitivity and specificity) of RCM for diagnosing BCC and dividing between subtypes, and throughput time. Patient satisfaction data will be collected postoperatively after 3 months during routine follow-up. This research is investigator-initiated and received ethics approval. Patient recruitment started in February 2015, and we expect all study-related activities to be completed by fall 2015. This RCT is the first to examine an OSS concept using RCM for diagnosing and treating clinically suspected BCC lesions. Results of this research are expected to have applications in evidence

  18. Characterisation of the selective binding of antibiotics vancomycin and teicoplanin by the VanS receptor regulating type A vancomycin resistance in the enterococci.

    PubMed

    Hughes, C S; Longo, E; Phillips-Jones, M K; Hussain, R

    2017-08-01

    A-type resistance towards "last-line" glycopeptide antibiotic vancomycin in the leading hospital acquired infectious agent, the enterococci, is the most common in the UK. Resistance is regulated by the VanR A S A two-component system, comprising the histidine sensor kinase VanS A and the partner response regulator VanR A . The nature of the activating ligand for VanS A has not been identified, therefore this work sought to identify and characterise ligand(s) for VanS A . In vitro approaches were used to screen the structural and activity effects of a range of potential ligands with purified VanS A protein. Of the screened ligands (glycopeptide antibiotics vancomycin and teicoplanin, and peptidoglycan components N-acetylmuramic acid, D-Ala-D-Ala and Ala-D-y-Glu-Lys-D-Ala-D-Ala) only glycopeptide antibiotics vancomycin and teicoplanin were found to bind VanS A with different affinities (vancomycin 70μM; teicoplanin 30 and 170μM), and were proposed to bind via exposed aromatic residues tryptophan and tyrosine. Furthermore, binding of the antibiotics induced quicker, longer-lived phosphorylation states for VanS A , proposing them as activators of type A vancomycin resistance in the enterococci. Copyright © 2017 Diamond Light Source Ltd. Published by Elsevier B.V. All rights reserved.

  19. Softwaremodule voor het Simuleren van de Gevolgen van Raketonderschepping (The Dutch Program for the Simulation of Missile Intercept Effects)

    DTIC Science & Technology

    2007-07-01

    effects (Softwaremodule voor het simuleren van de gevolgen van raketonderschepping) 11 . AUTHOR(S) Dr E. Abadjieva, MSc R.P. Sterkenburg, MSc F. Bouquet...Softwaremnodule voor het simuleren van de gevolgen van raketonderschepping D)attini Juli 2007 Auteur(s) dr. F. Abadjicva ir. R.P Sterkenburg ir. F. Bouquet ir...P.W. D)ouip Rubricering rapport O)ngerubri ceerd Vastgesteld door Maj R. 11 . Jongkinid Vastgesteld d.d. 12 juni 2007 (Deze nitining mizil-4 sict

  20. Beslisbevoegdheden en Verantwoordelijkheden van de Uitgestegen Soldaat. Deel A: Verplaatsen van Beslisbevoegdheden (Authority and Responsibility of the Dismounted Soldier. Part A. Empowering the Dismounted Soldier)

    DTIC Science & Technology

    2007-04-01

    en verantwoordelijkheden van de uitgestegen soldaat Deel A: verplaatsen van beslisbevoegdheden Datumn april 2007 Auteur (s) R. de Bruin ITE. van Bernmel...Admiraal, Bureau SMP Auteur (s) R. de Bruin Program maleider Projectleider I.E. van Bemnmel dr. W.A. Lotens, A.J. van Vliet, A.J. van Vijet TNO Defensie en...Leadership Theory en wordt relevant geacht voor de ontvangers van aanvullende beslisbevoegdheden. 2.1.3 Het oogmerk van de hogere commandant Een ander

  1. The phosphotransferase VanU represses expression of four qrr genes antagonizing VanO-mediated quorum-sensing regulation in Vibrio anguillarum

    PubMed Central

    Weber, Barbara; Lindell, Kristoffer; El Qaidi, Samir; Hjerde, Erik; Willassen, Nils-Peder

    2011-01-01

    Vibrio anguillarum utilizes quorum sensing to regulate stress responses required for survival in the aquatic environment. Like other Vibrio species, V. anguillarum contains the gene qrr1, which encodes the ancestral quorum regulatory RNA Qrr1, and phosphorelay quorum-sensing systems that modulate the expression of small regulatory RNAs (sRNAs) that destabilize mRNA encoding the transcriptional regulator VanT. In this study, three additional Qrr sRNAs were identified. All four sRNAs were positively regulated by σ54 and the σ54-dependent response regulator VanO, and showed a redundant activity. The Qrr sRNAs, together with the RNA chaperone Hfq, destabilized vanT mRNA and modulated expression of VanT-regulated genes. Unexpectedly, expression of all four qrr genes peaked at high cell density, and exogenously added N-acylhomoserine lactone molecules induced expression of the qrr genes at low cell density. The phosphotransferase VanU, which phosphorylates and activates VanO, repressed expression of the Qrr sRNAs and stabilized vanT mRNA. A model is presented proposing that VanU acts as a branch point, aiding cross-regulation between two independent phosphorelay systems that activate or repress expression of the Qrr sRNAs, giving flexibility and precision in modulating VanT expression and inducing a quorum-sensing response to stresses found in a constantly changing aquatic environment. PMID:21948044

  2. The phosphotransferase VanU represses expression of four qrr genes antagonizing VanO-mediated quorum-sensing regulation in Vibrio anguillarum.

    PubMed

    Weber, Barbara; Lindell, Kristoffer; El Qaidi, Samir; Hjerde, Erik; Willassen, Nils-Peder; Milton, Debra L

    2011-12-01

    Vibrio anguillarum utilizes quorum sensing to regulate stress responses required for survival in the aquatic environment. Like other Vibrio species, V. anguillarum contains the gene qrr1, which encodes the ancestral quorum regulatory RNA Qrr1, and phosphorelay quorum-sensing systems that modulate the expression of small regulatory RNAs (sRNAs) that destabilize mRNA encoding the transcriptional regulator VanT. In this study, three additional Qrr sRNAs were identified. All four sRNAs were positively regulated by σ(54) and the σ(54)-dependent response regulator VanO, and showed a redundant activity. The Qrr sRNAs, together with the RNA chaperone Hfq, destabilized vanT mRNA and modulated expression of VanT-regulated genes. Unexpectedly, expression of all four qrr genes peaked at high cell density, and exogenously added N-acylhomoserine lactone molecules induced expression of the qrr genes at low cell density. The phosphotransferase VanU, which phosphorylates and activates VanO, repressed expression of the Qrr sRNAs and stabilized vanT mRNA. A model is presented proposing that VanU acts as a branch point, aiding cross-regulation between two independent phosphorelay systems that activate or repress expression of the Qrr sRNAs, giving flexibility and precision in modulating VanT expression and inducing a quorum-sensing response to stresses found in a constantly changing aquatic environment.

  3. Synthetic Minor NSR Permit: Van Hook Crude Terminal, LLC - Van Hook Crude Terminal/Rail Loading Facility

    EPA Pesticide Factsheets

    This page contains the current effective synthetic minor NSR permit for the Van Hook Crude Terminal, LLC, Van Hook Crude Terminal/Rail Loading Facility, located on the Fort Berthold Indian Reservation in Mountrail County, ND.

  4. Glycopeptide Resistance vanA Operons in Paenibacillus Strains Isolated from Soil

    PubMed Central

    Guardabassi, Luca; Perichon, Bruno; van Heijenoort, Jean; Blanot, Didier; Courvalin, Patrice

    2005-01-01

    The sequence and gene organization of the van operons in vancomycin (MIC of >256 μg/ml)- and teicoplanin (MIC of ≥32 μg/ml)-resistant Paenibacillus thiaminolyticus PT-2B1 and Paenibacillus apiarius PA-B2B isolated from soil were determined. Both operons had regulatory (vanR and vanS), resistance (vanH, vanA, and vanX), and accessory (vanY, vanZ, and vanW) genes homologous to the corresponding genes in enterococcal vanA and vanB operons. The vanAPT operon in P. thiaminolyticus PT-2B1 had the same gene organization as that of vanA operons whereas vanAPA in P. apiarius PA-B2B resembled vanB operons due to the presence of vanW upstream from the vanHAX cluster but was closer to vanA operons in sequence. Reference P. apiarius strains NRRL B-4299 and NRRL B-4188 were found to harbor operons indistinguishable from vanAPA by PCR mapping, restriction fragment length polymorphism, and partial sequencing, suggesting that this operon was species specific. As in enterococci, resistance was inducible by glycopeptides and associated with the synthesis of pentadepsipeptide peptidoglycan precursors ending in d-Ala-d-Lac, as demonstrated by d,d-dipeptidase activities, high-pressure liquid chromatography, and mass spectrometry. The precursors differed from those in enterococci by the presence of diaminopimelic acid instead of lysine in the peptide chain. Altogether, the results are compatible with the notion that van operons in soil Paenibacillus strains and in enterococci have evolved from a common ancestor. PMID:16189102

  5. Glycopeptide resistance vanA operons in Paenibacillus strains isolated from soil.

    PubMed

    Guardabassi, Luca; Perichon, Bruno; van Heijenoort, Jean; Blanot, Didier; Courvalin, Patrice

    2005-10-01

    The sequence and gene organization of the van operons in vancomycin (MIC of >256 microg/ml)- and teicoplanin (MIC of > or =32 microg/ml)-resistant Paenibacillus thiaminolyticus PT-2B1 and Paenibacillus apiarius PA-B2B isolated from soil were determined. Both operons had regulatory (vanR and vanS), resistance (vanH, vanA, and vanX), and accessory (vanY, vanZ, and vanW) genes homologous to the corresponding genes in enterococcal vanA and vanB operons. The vanA(PT) operon in P. thiaminolyticus PT-2B1 had the same gene organization as that of vanA operons whereas vanA(PA) in P. apiarius PA-B2B resembled vanB operons due to the presence of vanW upstream from the vanHAX cluster but was closer to vanA operons in sequence. Reference P. apiarius strains NRRL B-4299 and NRRL B-4188 were found to harbor operons indistinguishable from vanA(PA) by PCR mapping, restriction fragment length polymorphism, and partial sequencing, suggesting that this operon was species specific. As in enterococci, resistance was inducible by glycopeptides and associated with the synthesis of pentadepsipeptide peptidoglycan precursors ending in D-Ala-D-Lac, as demonstrated by D,D-dipeptidase activities, high-pressure liquid chromatography, and mass spectrometry. The precursors differed from those in enterococci by the presence of diaminopimelic acid instead of lysine in the peptide chain. Altogether, the results are compatible with the notion that van operons in soil Paenibacillus strains and in enterococci have evolved from a common ancestor.

  6. Jao Van De Lagemaat | NREL

    Science.gov Websites

    Jao Van De Lagemaat Photo of Jao Vandelagemaat. Jao Van De Lagemaat Center Director: Chemistry and Lagemaat is currently the Center Director of the Chemistry and Nanoscience Center at NREL. He received his university. Education Ph.D. Physical Chemistry, University of Utrecht Featured Publications View all NREL

  7. Obituary: James Alfred Van Allen, 1914-2006

    NASA Astrophysics Data System (ADS)

    Ludwig, George H.; McIlwain, Carl Edwin

    2006-12-01

    James Alfred Van Allen, world-renowned space scientist, died 9 August 2006 at the age of ninety-one. He succumbed to heart failure after a ten-week period of declining health. Van Allen served for his entire sixty-seven-year professional career as an amazingly productive researcher, space science spokesman, inspired teacher, and valued colleague. The realization by him and his associates that charged particles are trapped by the Earth's magnetic field began a whole new field of research, magnetospheric physics. Following that initial discovery, he and his associates quickly extended their observations, first to the inner planets, and then to the rest of the planets and beyond. During his tenure at Iowa, he and his group flew instruments on more than sixty successful Earth satellites and planetary spacecraft, including the first missions to the planets Venus, Mars, Jupiter, Saturn, Uranus, and Neptune. Van Allen's lifetime publication list numbers more than 275, of which many are widely-cited, seminal papers. He was the sole author of more than 125 of those papers. Beyond the research laboratory, Van Allen worked energetically throughout his career in establishing space research as a new branch of human inquiry. He was among the most sought-after as a committee member and adviser, working at the highest levels of government, including the White House and Congress, and at all levels of the national and international research establishments. Many presentations in the non-scientific arena helped to bring the exciting discoveries and challenges of space research to the attention of the general public. James Van Allen (Van to his many friends and colleagues) was born on 7 September 1914 on a small farm near Mount Pleasant, Iowa, the second of four sons of Alfred Morris Van Allen and Alma Olney Van Allen. After high school in Mount Pleasant, he entered Iowa Wesleyan College, majoring in physics and graduating summa cum laude. While there, he was introduced to geophysics

  8. Consequences of the Introduction of Insensitive Munitions on Safety, Collateral Damage and Operations (consequenties van de invoering van mkm-munitie op veiligheid, gevolgschade en (internationaal) opereren

    DTIC Science & Technology

    2006-06-01

    van de werkzaamheden In dit rapport worden de gevolgen van initiatie van munitie door een ongewilde externe stimulus beschouwd aan de hand van reele...operationele scenario’s. Dit wordt vergeleken met de gevolgen in dezelfde scenario’s, waarin gebruik is gemaakt van Minder Kwetsbare Munitie (MKM). Naast...de historie van MKM wordt uitgelegd wat Inleiding of terroristische activiteiten, maar ook door MKM is. Vervolgens worden de gevolgen Munitie en de

  9. Chlorhexidine Induces VanA-Type Vancomycin Resistance Genes in Enterococci

    PubMed Central

    Bhardwaj, Pooja; Ziegler, Elizabeth

    2016-01-01

    Chlorhexidine is a bisbiguanide antiseptic used for infection control. Vancomycin-resistant E. faecium (VREfm) is among the leading causes of hospital-acquired infections. VREfm may be exposed to chlorhexidine at supra- and subinhibitory concentrations as a result of chlorhexidine bathing and chlorhexidine-impregnated central venous catheter use. We used RNA sequencing to investigate how VREfm responds to chlorhexidine gluconate exposure. Among the 35 genes upregulated ≥10-fold after 15 min of exposure to the MIC of chlorhexidine gluconate were those encoding VanA-type vancomycin resistance (vanHAX) and those associated with reduced daptomycin susceptibility (liaXYZ). We confirmed that vanA upregulation was not strain or species specific by querying other VanA-type VRE. VanB-type genes were not induced. The vanH promoter was found to be responsive to subinhibitory chlorhexidine gluconate in VREfm, as was production of the VanX protein. Using vanH reporter experiments with Bacillus subtilis and deletion analysis in VREfm, we found that this phenomenon is VanR dependent. Deletion of vanR did not result in increased chlorhexidine susceptibility, demonstrating that vanHAX induction is not protective against chlorhexidine. As expected, VanA-type VRE is more susceptible to ceftriaxone in the presence of sub-MIC chlorhexidine. Unexpectedly, VREfm is also more susceptible to vancomycin in the presence of subinhibitory chlorhexidine, suggesting that chlorhexidine-induced gene expression changes lead to additional alterations in cell wall synthesis. We conclude that chlorhexidine induces expression of VanA-type vancomycin resistance genes and genes associated with daptomycin nonsusceptibility. Overall, our results indicate that the impacts of subinhibitory chlorhexidine exposure on hospital-associated pathogens should be further investigated in laboratory studies. PMID:26810654

  10. Emergence of vanA Enterococcus faecium in Denmark, 2005-15.

    PubMed

    Hammerum, Anette M; Baig, Sharmin; Kamel, Yasmin; Roer, Louise; Pinholt, Mette; Gumpert, Heidi; Holzknecht, Barbara; Røder, Bent; Justesen, Ulrik S; Samulioniené, Jurgita; Kjærsgaard, Mona; Østergaard, Claus; Holm, Anette; Dzajic, Esad; Søndergaard, Turid Snekloth; Gaini, Shahin; Edquist, Petra; Alm, Erik; Lilje, Berit; Westh, Henrik; Stegger, Marc; Hasman, Henrik

    2017-08-01

    To describe the changing epidemiology of vancomycin-resistant Enterococcus faecium and Enterococcus faecalis in clinical samples in Denmark 2005-15 according to species and van type, and, furthermore, to investigate the genetic relatedness of the clinical E. faecium isolates from 2015. During 2005-14, all clinical VRE isolates were tested for the presence of vanA/B/C genes by PCR. In 2015, all clinical VRE isolates were whole-genome sequenced. From the WGS data, the presence of van genes and MLST STs were extracted in silico . Core-genome MLST (cgMLST) analysis was performed for the vancomycin-resistant E. faecium isolates. During 2005-15, 1043 vanA E. faecium , 25 vanB E. faecium , 4 vanA E. faecalis and 28 vanB E. faecalis were detected. The number of VRE was <50 isolates/year until 2012 to > 200 isolates/year in 2013-15. In 2015, 368 vanA E. faecium and 1 vanB E. faecium were detected along with 1 vanA E. faecalis and 1 vanB E. faecalis . cgMLST subdivided the 368 vanA E. faecium isolates into 33 cluster types (CTs), whereas the vanB E. faecium isolate belonged to a different CT. ST203-CT859 was most prevalent (51%), followed by ST80-CT14 (22%), ST117-CT24 (6%), ST80-CT866 (4%) and ST80-CT860 (2%). Comparison with the cgMLST.org database, previous studies and personal communications with neighbouring countries revealed that the novel cluster ST203-CT859 emerged in December 2014 and spread to the south of Sweden and the Faroe Islands during 2015. VRE increased in Denmark during 2005-15 due to the emergence of several vanA E. faecium clones. © The Author 2017. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. A Conversation with William Van Til.

    ERIC Educational Resources Information Center

    Beineke, John A.

    1989-01-01

    Reports an interview with William Van Til, Coffman Distinguished Professor Emeritus of Education at Indiana State University (Terre Haute). Van Til reviews his career as a social studies teacher and his writings on curriculum and social foundations. Presents his opinions on progressive education, famous educators, educational history and reform,…

  12. Additional Value from Road Mapping in Defense Policy Making (meerwaarde van roadmapping bij beleidsontwikkeling van de koninklijke landmacht)

    DTIC Science & Technology

    2006-05-01

    van zogonaamde strategische reserves tot bijvaarbeeld lakaal boschikbare gevechtscapacitoit. 9 11 Joint. Do Nederlandse krijgsmacht ontwikkelt zich tot...8 2 W erkwijze van de KL tot nu toe ............................................................................... 9 2.1 O...ntwikkeling visiedocurnent ....................................................................................... 9 2.2 Opzet beleid- en deelstudies

  13. Transient aerodynamic characteristics of vans during the accelerated overtaking process

    NASA Astrophysics Data System (ADS)

    Liu, Li-ning; Wang, Xing-shen; Du, Guang-sheng; Liu, Zheng-gang; Lei, Li

    2018-04-01

    This paper studies the influence of the accelerated overtaking process on the vehicles' transient aerodynamic characteristics, through 3-D numerical simulations with dynamic meshes and sliding interface technique. Numerical accuracy is verified by experimental results. The aerodynamic characteristics of vehicles in the uniform overtaking process and the accelerated overtaking process are compared. It is shown that the speed variation of the overtaking van would influence the aerodynamic characteristics of the two vans, with greater influence on the overtaken van than on the overtaking van. The simulations of three different accelerated overtaking processes show that the greater the acceleration of the overtaking van, the larger the aerodynamic coefficients of the overtaken van. When the acceleration of the overtaking van increases by 1 m/s2, the maximum drag force, side force and yawing moment coefficients of the overtaken van all increase by more than 6%, to seriously affect the power performance and the stability of the vehicles. The analysis of the pressure fields under different accelerated conditions reveals the cause of variations of the aerodynamic characteristics of vehicles.

  14. The Dramatic Methods of Hans van Dam.

    ERIC Educational Resources Information Center

    van de Water, Manon

    1994-01-01

    Interprets for the American reader the untranslated dramatic methods of Hans van Dam, a leading drama theorist in the Netherlands. Discusses the functions of drama as a method, closed dramatic methods, open dramatic methods, and applying van Dam's methods. (SR)

  15. Van der Waals interaction in uniaxial anisotropic media.

    PubMed

    Kornilovitch, Pavel E

    2013-01-23

    Van der Waals interactions between flat surfaces in uniaxial anisotropic media are investigated in the nonretarded limit. The main focus is the effect of nonzero tilt between the optical axis and the surface normal on the strength of the van der Waals attraction. General expressions for the van der Waals free energy are derived using the surface mode method and the transfer-matrix formalism. To facilitate numerical calculations a temperature-dependent three-band parameterization of the dielectric tensor of the liquid crystal 5CB is developed. A solid slab immersed in a liquid crystal experiences a van der Waals torque that aligns the surface normal relative to the optical axis of the medium. The preferred orientation is different for different materials. Two solid slabs in close proximity experience a van der Waals attraction that is strongest for homeotropic alignment of the intervening liquid crystal for all the materials studied. The results have implications for the stability of plate-like colloids in liquid crystal hosts.

  16. Margaret Cavendish's materialist critique of van Helmontian chymistry.

    PubMed

    Clucas, Stephen

    2011-03-01

    A striking omission in the scholarship on the reception of the chymical philosophy of Jan Baptista van Helmont in England in the seventeenth century is the work of the mid-seventeenth-century natural philosopher Margaret Cavendish, Duchess of Newcastle. In her Philosophical Letters (1664), Cavendish offers an extended critique of Van Helmont's work (whose Ortus Medicince had recently been translated into English by John Sadler). In this paper, I compare Cavendish's criticisms with those of Robert Boyle in his Sceptical Chymist (1661). Both Boyle and Cavendish attacked Van Helmont for the obscurity of his chymical vocabulary and concepts, and attacked his seminalism. Although their critiques had much in common, they diverged in their attitudes to Van Helmont's experiments. As an opponent of the experimental philosophy, Cavendish had little interest in the quality of Van Helmont's experimental claims, whereas Boyle was critical of their unreplicability. I also try to show that the two writers had very different polemical agendas, with Boyle defending his vision of chymistry based on a corpuscularian natural philosophy, and Cavendish being as much concerned with establishing her religious orthodoxy as with defending the truth claims of her own materialist vitalism. For Cavendish, Van Helmont was an example of the dangers of mingling theology and natural philosophy.

  17. Van Go: A Labor of Love

    ERIC Educational Resources Information Center

    Williams, Jennifer

    2012-01-01

    Like a tapestry woven with one outstanding thread from beginning to end, the author's forty-year tenure as an art educator has its golden thread in her Van Go art outreach project. Quite literally, she takes students in a "van" and they "go," mostly on dirt roads, taking art to rural schools in Idaho, some of which have no more…

  18. Genetics Home Reference: van der Woude syndrome

    MedlinePlus

    ... What is the prognosis of a genetic condition? Genetic and Rare Diseases Information Center Frequency Van der Woude syndrome is believed to occur in 1 in 35,000 to 1 in 100,000 people, based on data from Europe and Asia. Van der Woude syndrome ...

  19. UPS Hybrid Electric Delivery Van Testing | Transportation Research | NREL

    Science.gov Websites

    conventional diesel vans. Publications The following documents provide detailed information about the study the conventional vans during the on-road portion of the study. The two vehicle groups switched route assignments during the study period to provide a balanced review of the vans on the same routes. During

  20. Genetics Home Reference: Ellis-van Creveld syndrome

    MedlinePlus

    ... CREVELD SYNDROME Sources for This Page Baujat G, Le Merrer M. Ellis-van Creveld syndrome. Orphanet J Rare Dis. 2007 Jun ... CB, Kochilas L, Schimmenti LA, Moller JH. Ellis-van Creveld syndrome and congenital heart defects: presentation of an additional 32 cases. Pediatr Cardiol. 2011 Oct;32( ...

  1. Heath Van Essen

    EPA Pesticide Factsheets

    The EPA is providing notice of a proposed Administrative Penalty Assessment against Heath Van Essen, Respondent, an individual who owns or operates an animal feeding operation (“Facility”) that is located in Section 27 of Township 98 North, Range 47 West,

  2. 77 FR 14583 - Notice to Manufacturers of Alternative Fuel Vans

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-12

    ... Alternative Fuel Vans AGENCY: Federal Aviation Administration (FAA), U.S. DOT. ACTION: Notice to Manufacturers of Alternative Fuel Vans. SUMMARY: Projects funded under the Airport Improvement Program (AIP) must... (FAA) is considering issuing waivers to foreign manufacturers of alternative fuel vans. This notice...

  3. Obituary: Thomas C. Van Flandern (1940-2009)

    NASA Astrophysics Data System (ADS)

    Dunham, David; Slabinski, Victor

    2011-12-01

    Dr. Thomas Charles Van Flandern, an expert in celestial mechanics and cosmology, died January 9, 2009 in Seattle, Washington, of colon cancer. He was 68. Van Flandern was an astronomer at the U.S. Naval Observatory from 1963 to 1983. He developed software to predict and analyze lunar occultations to improve lunar orbital and fundamental star catalog data. In later years he championed increasingly controversial theories. But his 1978 prediction that some asteroids have natural satellites, which was almost universally rejected, was verified when the Galileo spacecraft photographed Dactyl, a satellite of (243) Ida, during its flyby in 1993. Besides astronomy and computers, he had strong interests in biochemistry and nutrition, and he ran a business selling personal computers in the 1980s. Tom Van Flandern was born June 26, 1940 in Cleveland, Ohio, the first child of Robert F. Van Flandern and Anna Mary Haley. His father, a police officer, left the family when Tom Van Flandern was 5. His mother died when he was 16; he and his siblings then lived with their grandmother, Margery Jobe, until he went to college. Tom Van Flandern became interested in astronomy as a child. He used his first telescope, purchased with newspaper delivery earnings, to observe lunar occultations, and then learned how to predict them, sparking a life-long passion for dynamical astronomy. While attending St. Ignatius High School, Van Flandern and fellow student Thomas Petrie organized the Cleveland Moonwatch team to observe the first artificial satellites, the only team without an adult organizer. In 1958, Tom Van Flandern entered Xavier University where he led the Cincinnati Moonwatch team. He learned computer programming at a summer job with General Electric and wrote software to calculate "look angles" from orbital elements. The Cincinnati team became a top producer of observations using these predictions. Tom obtained a B.S. in mathematics from Xavier in 1962. He spent the next year at

  4. Arnoldus Van Rhijn on aphasia: a forgotten thesis.

    PubMed

    Eling, Paul

    2011-01-01

    Aphasia formed a central topic in the discussion on localization of function in the nineteenth century, in particular in France, Germany and Great Brittain. Little is known on contributions from the Netherlands. This paper aims to discuss the contents of Arnoldus Van Rhijn's dissertation on aphasia, written in 1868 and one of the very few Dutch contributions to aphasiology in the nineteenth century. Added to this paper is a translation of the "Physiological Part" of Van Rhijn's dissertation. Van Rhijn discussed three cases with acquired aphasia. He rejected Broca's notion of a cortical center for the articulation of speech and instead regarded the cortex as the site where the will exerted its influence. He argued that there is a certain form of specialization: the will to say something is localized at a different place than the will to write. According to Van Rhijn, the highest motor centers are localized in the subcortical gray areas. Van Rhijn concluded that aphasia may result from lesions to the cortical centers involved in speaking, or from a disconnection of the cortical and subcortical centers. Very little work was done on aphasia in the 19th century in the Netherlands. Van Rhijn's thesis, from an aphasiological point of view of limited value, does show that the notions of "centers", "connections", and "disorders due to disconnections" were generally known before Wernicke, also in the Netherlands. Copyright © 2011 Elsevier Srl. All rights reserved.

  5. Moment tensor inversion of recent local moderate sized Van Earthquakes: seismicity and active tectonics of the Van region : Eastern Turkey

    NASA Astrophysics Data System (ADS)

    Kalafat, D.; Suvarikli, M.; Ogutcu, Z.; Kekovali, K.; Ocal, M. F.; Gunes, Y.; Pinar, A.

    2013-12-01

    The study area of the present research, the Van Region is located at the norththern end of the collision zone between the Anatolia and Arabian plates. Therefore, the southeast border of the Anatolian plate collides with the Arabian plate along the Bitlis Suture Zone. This zone is formed by collision of Arabian and in large scale Eurasian plates at mid-Miocen age. This type of thrust generation as a result of compressional regime extends east-west. The largest recorded earthquakes have all taken place along Southern Turkey (e.g. Lice, 1971; Varto, 1966; Caldiran, 1976). On the 23th of October 2011, an earthquake shook the Van Lake, Eastern Turkey, following a seismic sequence of more than three months in an unprecedented episode for this region characterized by null or low seismicity. The October 23, 2011 Van-Ercis Earthquake (Mw=7.1) was the most devastating resulting in loss of life and destruction. In order to study the aftershocks' activity of this main event, we installed and kept a seismic network of 10 broad-band (BB) stations in the area for an interval of nearly fifteen months. We characterized the seismogenic structure of the zone by calculating a minimum 1-D local velocity model and obtaining precise hypocentre locations. We also calculated fault plane solutions for more than 200 moderate sized earthquakes based on first motion polarities and commonly Moment Tensor Inversion Methods. The seismogenic zone would be localized at aproximately 10 km depth. Generally, the distribution of the important moderate earthquakes and the aftershock distribution shows that the E-W and NE-SW oriented fault segments cause the earthquake activities. Aftershock events are located along the eastern border of Lake Van and mainly between 5 and 10 km depth and disposed in two alignments: a ~E-W-trending alignment that matches with the trace of the Van Trust fault Zone and a NE-trending which could correspond to an structure not previously seen. Selected focal mechanisms show a

  6. [Implementation of vanA and vanB genes by PCR technique research interest in system (Xpert vanA/vanB CepheidR) closed in a laboratory of microbiology in managing an outbreak to Enterococcus faecium resistant glycopeptide (EfRG)].

    PubMed

    Dekeyser, S; Beclin, E; Descamps, D

    2011-04-01

    The closed system PCR for the rapid detection of vanA and vanB genes (Xpert vanA/vanB Cepheid(®)) was evaluated in our laboratory, to improve the rapidity of the response and thus the management of patients and isolation measures during two GRE outbreaks. From March to December2009, 565 samples were analysed by PCR associated to bacterial culture initially for all samples for 2months (n = 75), and thereafter for PCR-positive samples only. In this study, sensitivity and negative predictive values of the PCR were 100%. Specificity was evaluated in the presence and absence of outbreak: 69.3 and 76.8% respectively. The variability of false positive rates between units were lower in nonepidemic than during epidemic phase. The global false positive rate was 23.9%. This easy-to-use technology provides rapid results… four samples are tested in 1h versus 72h for culture. Despite its reagent cost, it represents an important hospital diagnostic tool: improvement of the management of cohorting areas and patient transfer between units, adaptation of isolation measures and treatments. However, culture remains necessary to confirm any positive result obtained by PCR and for epidemiological surveillance. Copyright © 2010 Elsevier Masson SAS. All rights reserved.

  7. Effective field theories for van der Waals interactions

    NASA Astrophysics Data System (ADS)

    Brambilla, Nora; Shtabovenko, Vladyslav; Tarrús Castellà, Jaume; Vairo, Antonio

    2017-06-01

    Van der Waals interactions between two neutral but polarizable systems at a separation R much larger than the typical size of the systems are at the core of a broad sweep of contemporary problems in settings ranging from atomic, molecular and condensed matter physics to strong interactions and gravity. In this paper, we reexamine the dispersive van der Waals interactions between two hydrogen atoms. The novelty of the analysis resides in the usage of nonrelativistic effective field theories of quantum electrodynamics. In this framework, the van der Waals potential acquires the meaning of a matching coefficient in an effective field theory, dubbed van der Waals effective field theory, suited to describe the low-energy dynamics of an atom pair. It may be computed systematically as a series in R times some typical atomic scale and in the fine-structure constant α . The van der Waals potential gets short-range contributions and radiative corrections, which we compute in dimensional regularization and renormalize here for the first time. Results are given in d space-time dimensions. One can distinguish among different regimes depending on the relative size between 1 /R and the typical atomic bound-state energy, which is of order m α2. Each regime is characterized by a specific hierarchy of scales and a corresponding tower of effective field theories. The short-distance regime is characterized by 1 /R ≫m α2 and the leading-order van der Waals potential is the London potential. We also compute next-to-next-to-next-to-leading-order corrections. In the long-distance regime we have 1 /R ≪m α2. In this regime, the van der Waals potential contains contact terms, which are parametrically larger than the Casimir-Polder potential that describes the potential at large distances. In the effective field theory, the Casimir-Polder potential counts as a next-to-next-to-next-to-leading-order effect. In the intermediate-distance regime, 1 /R ˜m α2, a significantly more complex

  8. The Economics of van der Waals Force Engineering

    NASA Astrophysics Data System (ADS)

    Pinto, Fabrizio

    2008-01-01

    As micro-electro-mechanical system (MEMS) fabrication continues on an ever-decreasing scale, new technological challenges must be successfully negotiated if Moore's Law is to be an even approximately valid model of the future of device miniaturization. Among the most significant obstacles is the existence of strong surface forces related to quantum mechanical van der Waals interatomic interactions, which rapidly diverge as the distance between any two neutral boundaries decreases. The van der Waals force is a contributing factor in several device failures and limitations, including, for instance, stiction and oscillator non-linearities. In the last decade, however, it has been conclusively shown that van der Waals forces are not just a MEMS limitation but can be engineered in both magnitude and sign so as to enable classes of proprietary inventions which either deliver novel capabilities or improve upon existing ones. The evolution of van der Waals force research from an almost exclusively theoretical field in quantum-electro-dynamics to an enabling nanotechnology discipline represents a useful example of the ongoing paradigm shift from government-centered to private-capital funded R&D in cutting-edge physics leading to potentially profitable products. In this paper, we discuss the reasons van der Waals force engineering may lead to the creation of thriving markets both in the short and medium terms by highlighting technical challenges that can be competitively addressed by this novel approach. We also discuss some notable obstacles to the cultural transformation of the academic research community required for the emergence of a functional van der Waals force engineering industry worldwide.

  9. Arthur van Gehuchten takes neurology to the movies.

    PubMed

    Aubert, Geneviève

    2002-11-26

    To present the cinematographic production of Arthur Van Gehuchten (1861-1914) and to put this collection into its medical and sociocultural context. The arrival of Edison's Kinetoscope (1891) and Lumière's Cinématographe (1895) provoked the immediate interest of neurologists who foresaw the potential of motion pictures for illustration, research, and teaching. Arthur Van Gehuchten, professor of anatomy and neurology at the Catholic University of Louvain, was trained as a microscopist and a cytologist. From neuroanatomy, he progressively broadened his interest to neurology. Van Gehuchten was an avant-garde teacher, eager to adopt new visual aids. In 1895, he attended the first cinematographic screenings. Medical cinematography was soon brought into disrepute in European academic circles, when films made by the French surgeon Doyen were copied and shown on fairgrounds. Nevertheless, in 1905, Van Gehuchten began to film neurologic patients. He used this technique extensively to demonstrate clinical signs, to illustrate neurologic diseases, and to document functional evolution following surgery. For decades, these films were screened for medical students by Van Gehuchten's successors to the chair of neurology. The original nitrate films (more than 2 hours) have been recently rediscovered. They have been restored by the Royal Belgian Film Archive, where they are the oldest Belgian films. At the beginning of the 20th century, Van Gehuchten built up a collection of moving pictures for teaching purposes. This was one of the first such undertakings. This unique set of films has miraculously survived, and serves as an important archive of nervous diseases and their manifestations prior to the advent of modern therapies.

  10. Nodal Statistics for the Van Vleck Polynomials

    NASA Astrophysics Data System (ADS)

    Bourget, Alain

    The Van Vleck polynomials naturally arise from the generalized Lamé equation as the polynomials of degree for which Eq. (1) has a polynomial solution of some degree k. In this paper, we compute the limiting distribution, as well as the limiting mean level spacings distribution of the zeros of any Van Vleck polynomial as N --> ∞.

  11. Vehicle test report: Jet Industries Electra Van 600

    NASA Technical Reports Server (NTRS)

    Price, T. W.; Wirth, V. A., Jr.

    1982-01-01

    The Electra Van 600, an electric vehicle, was tested. Tests were performed to characterize parameters of the Electra Van 600 and to provide baseline data to be used for comparison of improved batteries and to which will be incorporated into the vehicle. The vehicle tests concentrated on the electrical drive subsystem, the batteries, controller, and motor; coastdowns to characterize the road load and range evaluation for cyclic and constant speed conditions; and qualitative performance was evaluated. It is found that the Electra Van 600 range performance is approximately equal to the majority of the vehicles tested previously.

  12. Scaling laws for van der Waals interactions in nanostructured materials.

    PubMed

    Gobre, Vivekanand V; Tkatchenko, Alexandre

    2013-01-01

    Van der Waals interactions have a fundamental role in biology, physics and chemistry, in particular in the self-assembly and the ensuing function of nanostructured materials. Here we utilize an efficient microscopic method to demonstrate that van der Waals interactions in nanomaterials act at distances greater than typically assumed, and can be characterized by different scaling laws depending on the dimensionality and size of the system. Specifically, we study the behaviour of van der Waals interactions in single-layer and multilayer graphene, fullerenes of varying size, single-wall carbon nanotubes and graphene nanoribbons. As a function of nanostructure size, the van der Waals coefficients follow unusual trends for all of the considered systems, and deviate significantly from the conventionally employed pairwise-additive picture. We propose that the peculiar van der Waals interactions in nanostructured materials could be exploited to control their self-assembly.

  13. Rater Biases in Genetically Informative Research Designs: Comment on Bartels, Boomsma, Hudziak, van Beijsterveldt, and van den Oord (2007)

    ERIC Educational Resources Information Center

    Hoyt, William T.

    2007-01-01

    Rater biases are of interest to behavior genetic researchers, who often use ratings data as a basis for studying heritability. Inclusion of multiple raters for each sibling pair (M. Bartels, D. I. Boomsma, J. J. Hudziak, T. C. E. M. van Beijsterveldt, & E. J. C. G. van den Oord, 2007) is a promising strategy for controlling bias variance and may…

  14. RpoS induces expression of the Vibrio anguillarum quorum-sensing regulator VanT.

    PubMed

    Weber, Barbara; Croxatto, Antony; Chen, Chang; Milton, Debra L

    2008-03-01

    In vibrios, regulation of the Vibrio harveyi-like LuxR transcriptional activators occurs post-transcriptionally via small regulatory RNAs (sRNAs) that destabilize the luxR mRNA at a low cell population, eliminating expression of LuxR. Expression of the sRNAs is modulated by the vibrio quorum-sensing phosphorelay systems. However, vanT mRNA, which encodes a LuxR homologue in Vibrio anguillarum, is abundant at low and high cell density, indicating that VanT expression may be regulated via additional mechanisms. In this study, Western analyses showed that VanT was expressed throughout growth with a peak of expression during late exponential growth. VanO induced partial destabilization of vanT mRNA via activation of at least one Qrr sRNA. Interestingly, the sigma factor RpoS significantly stabilized vanT mRNA and induced VanT expression during late exponential growth. This induction was in part due to RpoS repressing expression of Hfq, an RNA chaperone. RpoS is not part of the quorum-sensing regulatory cascade since RpoS did not regulate expression or activity of VanO, and RpoS was not regulated by VanO or VanT. VanT and RpoS were needed for survival following UV irradiation and for pigment and metalloprotease production, suggesting that RpoS works with the quorum-sensing systems to modulate expression of VanT, which regulates survival and stress responses.

  15. van Manen's method and reduction in a phenomenological hermeneutic study.

    PubMed

    Heinonen, Kristiina

    2015-03-01

    To describe van Manen's method and concept of reduction in a study that used a phenomenological hermeneutic approach. Nurse researchers have used van Manen's method in different ways. Participants' lifeworlds are described in depth, but descriptions of reduction have been brief. The literature and knowledge review and manual search of research articles. Databases Web Science, PubMed, CINAHL and PsycINFO, without applying a time period, to identify uses of van Manen's method. This paper shows how van Manen's method has been used in nursing research and gives some examples of van Manen's reduction. Reduction enables us to conduct in-depth phenomenological hermeneutic research and understand people's lifeworlds. As there are many variations in adapting reduction, it is complex and confusing. This paper contributes to the discussion of phenomenology, hermeneutic study and reduction. It opens up reduction as a method for researchers to exploit.

  16. Genomic and expression analysis of the vanG-like gene cluster of Clostridium difficile.

    PubMed

    Peltier, Johann; Courtin, Pascal; El Meouche, Imane; Catel-Ferreira, Manuella; Chapot-Chartier, Marie-Pierre; Lemée, Ludovic; Pons, Jean-Louis

    2013-07-01

    Primary antibiotic treatment of Clostridium difficile intestinal diseases requires metronidazole or vancomycin therapy. A cluster of genes homologous to enterococcal glycopeptides resistance vanG genes was found in the genome of C. difficile 630, although this strain remains sensitive to vancomycin. This vanG-like gene cluster was found to consist of five ORFs: the regulatory region consisting of vanR and vanS and the effector region consisting of vanG, vanXY and vanT. We found that 57 out of 83 C. difficile strains, representative of the main lineages of the species, harbour this vanG-like cluster. The cluster is expressed as an operon and, when present, is found at the same genomic location in all strains. The vanG, vanXY and vanT homologues in C. difficile 630 are co-transcribed and expressed to a low level throughout the growth phases in the absence of vancomycin. Conversely, the expression of these genes is strongly induced in the presence of subinhibitory concentrations of vancomycin, indicating that the vanG-like operon is functional at the transcriptional level in C. difficile. Hydrophilic interaction liquid chromatography (HILIC-HPLC) and MS analysis of cytoplasmic peptidoglycan precursors of C. difficile 630 grown without vancomycin revealed the exclusive presence of a UDP-MurNAc-pentapeptide with an alanine at the C terminus. UDP-MurNAc-pentapeptide [d-Ala] was also the only peptidoglycan precursor detected in C. difficile grown in the presence of vancomycin, corroborating the lack of vancomycin resistance. Peptidoglycan structures of a vanG-like mutant strain and of a strain lacking the vanG-like cluster did not differ from the C. difficile 630 strain, indicating that the vanG-like cluster also has no impact on cell-wall composition.

  17. Van der waals forces on thin liquid films in capillary tubes

    SciTech Connect

    Herdt, G.C.; Swanson, L.W.

    1993-10-01

    A theory of the van der Waals attraction between a thin liquid films and a capillary tube is presented assuming the presence of a vapor-liquid interface. The model is based on the surface mode analysis method of van Kampen et al. Values for the van der Waals interaction energy per unit area were calculated for liquid films of pentane on a gold substrate assuming a thin liquid film. Results indicate that the effect of capillary curvature on the van der Waals interaction increases as the ratio of the liquid film thickness to the capillary radius is increased. This trend ismore » consistent with predictions based on the Hamaker theory. Deviations from results based on the Hamaker theory are easily explained in terms of retardation of the van der Waals interaction. Because the effect of capillary curvature increases in the regime where retardation effects become important, curvature effects constitute a small correction to the van der Waals forces in a capillary tube.« less

  18. Waardering en Analyse van Simulatieresultaten (Valuation and Analysis of Simulation Results)

    DTIC Science & Technology

    1991-12-01

    is uit de tabel van de Students T-verdeling te halen . Deze wordt aangeduid met t,(v), waarin a de overschrijdingskans en v bet aantal vrijheidsgraden...2 vrijheidsgraden. Uit de tabol van de Student’s t-verdeling zija nu de kritieke waardon R, on R2 to halen zodanig dat P(t >R2 ) = i Wordt or eon...analyse van simnulatieresultaten - TDCnaK RAPPORTE1CENTRALE Frederikkazerne, Geb. 140 AD-A25 470van den Burchlaan 31AD-A25 470Telefoon: 070-3166394

  19. Martin Van Buren National Historic Site transportation analysis report

    DOT National Transportation Integrated Search

    2010-10-01

    The Volpe Transportation Systems Center (Volpe Center) is providing transportation support to Martin Van Buren National Historic Site's (NHS) first General Management Plan (GMP), which will be complete in 2010 or 2011. Currently, Martin Van Buren NHS...

  20. A. E. van Vogt: In Search of Meaning.

    ERIC Educational Resources Information Center

    Drake, H. L.

    A general semantics perspective of science fiction writer A. E. van Vogt is presented in this paper. The first major section of the paper contains a biographical sketch of van Vogt and traces the influence of A. Korzybski's work on general semantics, "Science and Sanity," on his writing, while the second major section provides an…

  1. Van Driest transformation and compressible wall-bounded flows

    NASA Technical Reports Server (NTRS)

    Huang, P. G.; Coleman, G. N.

    1994-01-01

    The transformation validity question utilizing resulting data from direct numerical simulations (DNS) of supersonic, isothermal cold wall channel flow was investigated. The DNS results stood for a wide scope of parameter and were suitable for the purpose of examining the generality of Van Driest transformation. The Van Driest law of the wall can be obtained from the inner-layer similarity arguments. It was demonstrated that the Van Driest transformation cannot be incorporated to collapse the sublayer and log-layer velocity profiles simultaneously. Velocity and temperature predictions according to the preceding composite mixing-length model were presented. Despite satisfactory congruity with the DNS data, the model must be perceived as an engineering guide and not as a rigorous analysis.

  2. Alternative Fuels Data Center: Natural Gas Delivery Vans Support McShan

    Science.gov Websites

    FloristA> Natural Gas Delivery Vans Support McShan Florist to someone by E-mail Share Alternative Natural Gas Delivery Vans Support McShan Florist Watch how a Dallas, Texas, florist reduces emissions and saves money fueling delivery vans with compressed natural gas. For information about this project

  3. Van de Hulst Essay: Light Scattering, Aerosols, Clouds, Climate, Hendrik van de Hulst, and I

    DOE PAGES

    Chylek, Petr

    2017-12-06

    It is not often that I have the opportunity to write something that is not a scientific study, and I am thankful for this opportunity to express my thoughts with regard to pursuits that are greater than those of science. In this van de Hulst assay, to honor Hendrik van de Hulst, I briefly summarize a few points from Hendrik's life that I find especially interesting, including his interests in spiritual (or religious) aspects of life, and his decision to avoid involvement in nucleation problems, a critical and basic uncertainty of current climate models. Finally, after that, I present brieflymore » a few episodes from my own experiences as an apprentice of science and life.« less

  4. Van de Hulst Essay: Light Scattering, Aerosols, Clouds, Climate, Hendrik van de Hulst, and I

    SciTech Connect

    Chylek, Petr

    It is not often that I have the opportunity to write something that is not a scientific study, and I am thankful for this opportunity to express my thoughts with regard to pursuits that are greater than those of science. In this van de Hulst assay, to honor Hendrik van de Hulst, I briefly summarize a few points from Hendrik's life that I find especially interesting, including his interests in spiritual (or religious) aspects of life, and his decision to avoid involvement in nucleation problems, a critical and basic uncertainty of current climate models. Finally, after that, I present brieflymore » a few episodes from my own experiences as an apprentice of science and life.« less

  5. Multiple Voices in Charles Van Riper's Desensitization Therapy

    ERIC Educational Resources Information Center

    Leahy, Margaret M.

    2008-01-01

    Background: Charles Van Riper (1905-94) author, researcher and practitioner, was one of the major contributors to the field of stuttering in the 20th century. His series of Action Therapy videotapes provide a useful model of how therapy was implemented by a master clinician. Aims: Van Riper's session with a client is analysed to reveal how voices…

  6. An historical note on the cell theory.

    PubMed

    Ribatti, Domenico

    2018-03-01

    The development of the microscope was a precondition for the discovery of cells. This instrument magnifies objects too small to be seen by the naked eye. In 1673, the Dutch botanist, Anton van Leeuwenhoek, made a more advanced microscope and reported seeing a myriad of microscopic "animalcules" in water. He also made further studies of red blood cells and sperm cells. Most studies that followed were done on the easily studied plant tissues. Plant cells, rigidly encased in their cell walls, were ideal to study in situ. The cell theory proposes that nucleated cells are the basic structure of plants and animals. This concept was observed and published separately, first by the botanist, Matthias Schleiden, in 1838, and then by the zoologist, Theodor Schwann, in 1839. Their work demonstrated that cells form the basic unit of life of plants and animals. Rudolf Virchow concluded that all living organisms are the sum of single cellular units and that cells multiply. Copyright © 2018 Elsevier Inc. All rights reserved.

  7. Militaire Toepassingen Van Adaptieve Optiek (Military Applications of Adaptive Optics)

    DTIC Science & Technology

    2006-09-01

    dat op dit moment met de beschikbare theorie mogelijk is. Een ander interessant aspect is de mate waarin de turbulentie effecten het jam patroon...systemen In WEAG studie JP8. 11 is aangetoond dat in theorie adaptieve technieken een verbetering van de prestaties van een DIRCM systeem kunnen...Molenaar; Theorie van de laserscintillometer; TNO repot PHL 1978-16 (1978). TNO-rapport I TNO-DV 2006 A336 35/35 6 Ondertekening Den Haag, september 2006

  8. Van Gogh from Space

    NASA Image and Video Library

    2017-12-08

    Van Gogh from Space - July 13th, 2005 Description: In the style of Van Gogh's painting "Starry Night," massive congregations of greenish phytoplankton swirl in the dark water around Gotland, a Swedish island in the Baltic Sea. Phytoplankton are microscopic marine plants that form the first link in nearly all ocean food chains. Population explosions, or blooms, of phytoplankton, like the one shown here, occur when deep currents bring nutrients up to sunlit surface waters, fueling the growth and reproduction of these tiny plants. Credit: USGS/NASA/Landsat 7 To learn more about the Landsat satellite go to: landsat.gsfc.nasa.gov/ NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Join us on Facebook

  9. Multilevel population genetic analysis of vanA and vanB Enterococcus faecium causing nosocomial outbreaks in 27 countries (1986-2012).

    PubMed

    Freitas, Ana R; Tedim, Ana P; Francia, Maria V; Jensen, Lars B; Novais, Carla; Peixe, Luísa; Sánchez-Valenzuela, Antonio; Sundsfjord, Arnfinn; Hegstad, Kristin; Werner, Guido; Sadowy, Ewa; Hammerum, Anette M; Garcia-Migura, Lourdes; Willems, Rob J; Baquero, Fernando; Coque, Teresa M

    2016-12-01

    Vancomycin-resistant Enterococcus faecium (VREfm) have been increasingly reported since the 1980s. Despite the high number of published studies about VRE epidemiology, the dynamics and evolvability of these microorganisms are still not fully understood. A multilevel population genetic analysis of VREfm outbreak strains since 1986, representing the first comprehensive characterization of plasmid content in E. faecium, was performed to provide a detailed view of potential transmissible units. From a comprehensive MeSH search, we identified VREfm strains causing hospital outbreaks (1986-2012). In total, 53 VanA and 18 VanB isolates (27 countries, 5 continents) were analysed and 82 vancomycin-susceptible E. faecium (VSEfm) were included for comparison. Clonal relatedness was established by PFGE and MLST (goeBURST/Bayesian Analysis of Population Structure, BAPS). Characterization of van transposons (PCR mapping, RFLP, sequencing), plasmids (transfer, ClaI-RFLP, PCR typing of relaxases, replication-initiation proteins and toxin-antitoxin systems, hybridization, sequencing), bacteriocins and virulence determinants (PCR, hybridization, sequencing) was performed. VREfm were mainly associated with major human lineages ST17, ST18 and ST78. VREfm and VSEfm harboured plasmids of different families [RCR, small theta plasmids, RepA_N (pRUM/pLG1) and Inc18] able to yield mosaic elements. Tn1546-vanA was mainly located on pRUM/Axe-Txe (USA) and Inc18-pIP186 (Europe) plasmids. The VanB2 type (Tn5382/Tn1549) was predominant among VanB strains (chromosome and plasmids). Both strains and plasmids contributed to the spread and persistence of vancomycin resistance among E. faecium. Horizontal gene transfer events among genetic elements from different clonal lineages (same or different species) result in chimeras with different stability and host range, complicating the surveillance of epidemic plasmids. © The Author 2016. Published by Oxford University Press on behalf of the British

  10. MATE (Mentale Aspecten van Team Effectiviteit) (MATE (Mental Aspects of Team Effectiveness))

    DTIC Science & Technology

    2008-05-01

    0 Auteur (s) drs. J.P. van Meer drs. MI. 1 ’ IIart0 drs. 1. van der 16. Rubricering rapport Ongerubriceerd Vastgesteld door Ikol drs. L.A. de Vos...team Auteur (s) Teamntraining drs. J.P. van Meer drs. M.H.E. I Hart Programmanummer Projectnummer drs. 1. van der Beijl V406 015.34095 Rubricering...Murphy & Cleveland (1995) geven inzicht in de tearngedragingen die meetbaar zijn en de theorie over Shared Mental Models (Espevik et al, 2006) laat zien

  11. Isotope separation by photodissociation of Van der Waal's molecules

    DOEpatents

    Lee, Yuan T.

    1977-01-01

    A method of separating isotopes based on the dissociation of a Van der Waal's complex. A beam of molecules of a Van der Waal's complex containing, as one partner of the complex, a molecular species in which an element is present in a plurality of isotopes is subjected to radiation from a source tuned to a frequency which will selectively excite vibrational motion by a vibrational transition or through electronic transition of those complexed molecules of the molecular species which contain a desired isotope. Since the Van der Waal's binding energy is much smaller than the excitational energy of vibrational motion, the thus excited Van der Waal's complex dissociate into molecular components enriched in the desired isotope. The recoil velocity associated with vibrational to translational and rotational relaxation will send the separated molecules away from the beam whereupon the product enriched in the desired isotope can be separated from the constituents of the beam.

  12. De Ontwikkeling van een PBPK Model voor VX; Stand van Zaken V013-813 en 207C (The Development of a PBPK Model for VX: Status Report)

    DTIC Science & Technology

    2006-02-01

    ing. H.C. Trap, dr. ir. M.J. van der werd zes maal gesproken over de Schans, ing. L.F. Chau, B.). Lander, invulling en de voortgang van het I.A. Cordia ...dr. ir. M.J. van der Schans, ing. L.F. Chau, J.P. Oostdijk, B.J. Lander, l.A. Cordia 25 TNO Defensie en Veiligheid, vestiging Rijswijk, Marketing en

  13. Electrons in the Inner Van Allen Belt

    SciTech Connect

    Reeves, Geoff

    A recent study shows that the inner Van Allen belt has less radiation than previously believed. Observations from NASA’s Van Allen probes show the fastest, most energetic electrons in the inner radiation belt are actually much rarer and harder to find than scientists expected. This is good news for spacecraft that are orbiting in the region and can be damaged by high levels of radiation. The results will also help scientists better understand—and detect—effects from high-altitude nuclear explosions.

  14. Energy Sources for Soldier Modernisation Programme Systems (Overzicht van Ontwikkelingen op het Gebied van Draagbare Energieopslag en Energieopwekking)

    DTIC Science & Technology

    1999-12-01

    9 . http://home.earthlink.net/-fradella/homepage.htm 10. http ://web.mit.edu/aeroastro/www/labs/GTL/research/micro/micro.html 11 . http://www.ecr.co.il...Meijer 7 LAS/DB&P/BO/OB&T taxv. aooi Jansen 8 LAS/DB&PIBO/OB 9 LAS/DB&P/BO/CIV 10 OGMAN/Externe plannen Infanterie 11 DM/C31 12 DM/COM 13 KPU-bedrijf 14...detailed specifications mentioned before. TNO-rapport TNO-MEP - R 99/490 9 van 51 Samenvatting In dit rapport wordt een eerste globale selectie gemaakt: van

  15. The research contributions of Dr. Paul Van Deusen

    Treesearch

    Thomas B. Lynch; Francis A. Roesch; John Paul McTague; Jeffrey H. Gove; Gregory A. Reams; Aaron R. Weiskittel

    2015-01-01

    Dr. Paul Van Deusen’s recent passing concluded a rich 30+-year research career dedicated to development and implementation of quantitative methods for forestry and natural resources. Since the early part of his career as a biometrician with the USDA Forest Service Southern Research Station in the 1980s-1990s and continuing with his later employment at NCASI, Dr. Van...

  16. Mapping Van

    NASA Technical Reports Server (NTRS)

    1994-01-01

    A NASA Center for the Commercial Development of Space (CCDS) - developed system for satellite mapping has been commercialized for the first time. Global Visions, Inc. maps an area while driving along a road in a sophisticated mapping van equipped with satellite signal receivers, video cameras and computer systems for collecting and storing mapping data. Data is fed into a computerized geographic information system (GIS). The resulting amps can be used for tax assessment purposes, emergency dispatch vehicles and fleet delivery companies as well as other applications.

  17. Novel type of VanB2 teicoplanin-resistant hospital-associated Enterococcus faecium.

    PubMed

    Santona, Antonella; Paglietti, Bianca; Al-Qahtani, Ahmed A; Bohol, Marie Fe F; Senok, Abiola; Deligios, Massimo; Rubino, Salvatore; Al-Ahdal, Mohammed N

    2014-08-01

    Seven high-risk clones of vancomycin-resistant Enterococcus faecium (VREF) belonging to clonal complex 17 were identified using multilocus sequence typing (MLST) among clinical isolates from Saudi Arabia. Among these isolates, a new hospital-associated sequence type (ST795), VanB(2)-type teicoplanin-resistant strain was detected. Its unusual phenotype resulted from a new combination of mutations in the ddl, vanS and vanW genes, which confirmed the trend of evolution in VanB-type resistance. Furthermore, characteristics of adaptation and persistence in the hospital environment of ST795 were emphasised by the presence of genes and clusters recognised to be specific for hospital-associated VREF. Copyright © 2014 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

  18. Materials perspective on Casimir and van der Waals interactions

    NASA Astrophysics Data System (ADS)

    Woods, L. M.; Dalvit, D. A. R.; Tkatchenko, A.; Rodriguez-Lopez, P.; Rodriguez, A. W.; Podgornik, R.

    2016-10-01

    Interactions induced by electromagnetic fluctuations, such as van der Waals and Casimir forces, are of universal nature present at any length scale between any types of systems. Such interactions are important not only for the fundamental science of materials behavior, but also for the design and improvement of micro- and nanostructured devices. In the past decade, many new materials have become available, which has stimulated the need for understanding their dispersive interactions. The field of van der Waals and Casimir forces has experienced an impetus in terms of developing novel theoretical and computational methods to provide new insights into related phenomena. The understanding of such forces has far reaching consequences as it bridges concepts in materials, atomic and molecular physics, condensed-matter physics, high-energy physics, chemistry, and biology. This review summarizes major breakthroughs and emphasizes the common origin of van der Waals and Casimir interactions. Progress related to novel ab initio modeling approaches and their application in various systems, interactions in materials with Dirac-like spectra, force manipulations through nontrivial boundary conditions, and applications of van der Waals forces in organic and biological matter are examined. The outlook of the review is to give the scientific community a materials perspective of van der Waals and Casimir phenomena and stimulate the development of experimental techniques and applications.

  19. Materials perspective on Casimir and van der Waals interactions

    SciTech Connect

    Woods, L. M.; Dalvit, D. A. R.; Tkatchenko, A.

    Interactions induced by electromagnetic fluctuations, such as van der Waals and Casimir forces, are of universal nature present at any length scale between any types of systems. In such interactions these are important not only for the fundamental science of materials behavior, but also for the design and improvement of micro- and nanostructured devices. In the past decade, many new materials have become available, which has stimulated the need for understanding their dispersive interactions. The field of van der Waals and Casimir forces has experienced an impetus in terms of developing novel theoretical and computational methods to provide new insightsmore » into related phenomena. The understanding of such forces has far reaching consequences as it bridges concepts in materials, atomic and molecular physics, condensed-matter physics, high-energy physics, chemistry, and biology. Our review summarizes major breakthroughs and emphasizes the common origin of van der Waals and Casimir interactions. Progress related to novel ab initio modeling approaches and their application in various systems, interactions in materials with Dirac-like spectra, force manipulations through nontrivial boundary conditions, and applications of van der Waals forces in organic and biological matter are examined. Finally, the outlook of the review is to give the scientific community a materials perspective of van der Waals and Casimir phenomena and stimulate the development of experimental techniques and applications.« less

  20. Materials perspective on Casimir and van der Waals interactions

    DOE PAGES

    Woods, L. M.; Dalvit, D. A. R.; Tkatchenko, A.; ...

    2016-11-02

    Interactions induced by electromagnetic fluctuations, such as van der Waals and Casimir forces, are of universal nature present at any length scale between any types of systems. In such interactions these are important not only for the fundamental science of materials behavior, but also for the design and improvement of micro- and nanostructured devices. In the past decade, many new materials have become available, which has stimulated the need for understanding their dispersive interactions. The field of van der Waals and Casimir forces has experienced an impetus in terms of developing novel theoretical and computational methods to provide new insightsmore » into related phenomena. The understanding of such forces has far reaching consequences as it bridges concepts in materials, atomic and molecular physics, condensed-matter physics, high-energy physics, chemistry, and biology. Our review summarizes major breakthroughs and emphasizes the common origin of van der Waals and Casimir interactions. Progress related to novel ab initio modeling approaches and their application in various systems, interactions in materials with Dirac-like spectra, force manipulations through nontrivial boundary conditions, and applications of van der Waals forces in organic and biological matter are examined. Finally, the outlook of the review is to give the scientific community a materials perspective of van der Waals and Casimir phenomena and stimulate the development of experimental techniques and applications.« less

  1. van der Waals torque

    NASA Astrophysics Data System (ADS)

    Esquivel-Sirvent, Raul; Schatz, George

    2014-03-01

    The theory of generalized van der Waals forces by Lifshtz when applied to optically anisotropic media predicts the existence of a torque. In this work we present a theoretical calculation of the van der Waals torque for two systems. First we consider two isotropic parallel plates where the anisotropy is induced using an external magnetic field. The anisotropy will in turn induce a torque. As a case study we consider III-IV semiconductors such as InSb that can support magneto plasmons. The calculations of the torque are done in the Voigt configuration, that occurs when the magnetic field is parallel to the surface of the slabs. The change in the dielectric function as the magnetic field increases has the effect of decreasing the van der Waals force and increasing the torque. Thus, the external magnetic field is used to tune both the force and torque. The second example we present is the use of the torque in the non retarded regime to align arrays of nano particle slabs. The torque is calculated within Barash and Ginzburg formalism in the nonretarded limit, and is quantified by the introduction of a Hamaker torque constant. Calculations are conducted between anisotropic slabs of materials including BaTiO3 and arrays of Ag nano particles. Depending on the shape and arrangement of the Ag nano particles the effective dielectric function of the array can be tuned as to make it more or less anisotropic. We show how this torque can be used in self assembly of arrays of nano particles. ref. R. Esquivel-Sirvent, G. C. Schatz, Phys. Chem C, 117, 5492 (2013). partial support from DGAPA-UNAM.

  2. Structural and Functional Adaptation of Vancomycin Resistance VanT Serine Racemases

    PubMed Central

    Meziane-Cherif, Djalal; Stogios, Peter J.; Evdokimova, Elena; Egorova, Olga

    2015-01-01

    ABSTRACT Vancomycin resistance in Gram-positive bacteria results from the replacement of the d-alanyl–d-alanine target of peptidoglycan precursors with d-alanyl–d-lactate or d-alanyl–d-serine (d-Ala-d-Ser), to which vancomycin has low binding affinity. VanT is one of the proteins required for the production of d-Ala-d-Ser-terminating precursors by converting l-Ser to d-Ser. VanT is composed of two domains, an N-terminal membrane-bound domain, likely involved in l-Ser uptake, and a C-terminal cytoplasmic catalytic domain which is related to bacterial alanine racemases. To gain insight into the molecular function of VanT, the crystal structure of the catalytic domain of VanTG from VanG-type resistant Enterococcus faecalis BM4518 was determined. The structure showed significant similarity to type III pyridoxal 5′-phosphate (PLP)-dependent alanine racemases, which are essential for peptidoglycan synthesis. Comparative structural analysis between VanTG and alanine racemases as well as site-directed mutagenesis identified three specific active site positions centered around Asn696 which are responsible for the l-amino acid specificity. This analysis also suggested that VanT racemases evolved from regular alanine racemases by acquiring additional selectivity toward serine while preserving that for alanine. The 4-fold-lower relative catalytic efficiency of VanTG against l-Ser versus l-Ala implied that this enzyme relies on its membrane-bound domain for l-Ser transport to increase the overall rate of d-Ser production. These findings illustrate how vancomycin pressure selected for molecular adaptation of a housekeeping enzyme to a bifunctional enzyme to allow for peptidoglycan remodeling, a strategy increasingly observed in antibiotic-resistant bacteria. PMID:26265719

  3. Structural and functional adaptation of vancomycin resistance VanT serine racemases

    DOE PAGES

    Meziane-Cherif, Djalal; Stogios, Peter J.; Evdokimova, Elena; ...

    2015-08-11

    Vancomycin resistance in Gram-positive bacteria results from the replacement of the D-alanyl–D-alanine target of peptidoglycan precursors with D-alanyl–D-lactate or D-alanyl–D-serine (D-Ala-D-Ser), to which vancomycin has low binding affinity. VanT is one of the proteins required for the production of D-Ala-D-Ser-terminating precursors by converting L-Ser to D-Ser. VanT is composed of two domains, an N-terminal membrane-bound domain, likely involved in L-Ser uptake, and a C-terminal cytoplasmic catalytic domain which is related to bacterial alanine racemases. To gain insight into the molecular function of VanT, the crystal structure of the catalytic domain of VanT G from VanG-type resistant Enterococcus faecalis BM4518more » was determined. The structure showed significant similarity to type III pyridoxal 5'-phosphate (PLP)-dependent alanine racemases, which are essential for peptidoglycan synthesis. Comparative structural analysis between VanT G and alanine racemases as well as site-directed mutagenesis identified three specific active site positions centered around Asn 696 which are responsible for theL-amino acid specificity. This analysis also suggested that VanT racemases evolved from regular alanine racemases by acquiring additional selectivity toward serine while preserving that for alanine. The 4-fold-lower relative catalytic efficiency of VanT G against L-Ser versus L-Ala implied that this enzyme relies on its membrane-bound domain for L-Ser transport to increase the overall rate of D-Ser production. These findings illustrate how vancomycin pressure selected for molecular adaptation of a housekeeping enzyme to a bifunctional enzyme to allow for peptidoglycan remodeling, a strategy increasingly observed in antibiotic-resistant bacteria.« less

  4. Modified Van der Waals equation and law of corresponding states

    NASA Astrophysics Data System (ADS)

    Zhong, Wei; Xiao, Changming; Zhu, Yongkai

    2017-04-01

    It is well known that the Van der Waals equation is a modification of the ideal gas law, yet it can be used to describe both gas and liquid, and some important messages can be obtained from this state equation. However, the Van der Waals equation is not a precise state equation, and it does not give a good description of the law of corresponding states. In this paper, we expand the Van der Waals equation into its Taylor's series form, and then modify the fourth order expansion by changing the constant Virial coefficients into their analogous ones. Via this way, a more precise result about the law of corresponding states has been obtained, and the law of corresponding states can then be expressed as: in terms of the reduced variables, all fluids should obey the same equation with the analogous Virial coefficients. In addition, the system of 3 He with quantum effects has also been taken into consideration with our modified Van der Waals equation, and it is found that, for a normal system without quantum effect, the modification on ideal gas law from the Van der Waals equation is more significant than the real case, however, for a system with quantum effect, this modification is less significant than the real case, thus a factor is introduced in this paper to weaken or strengthen the modification of the Van der Waals equation, respectively.

  5. Huntsville, Alabama, Volunteer Van Demonstration

    DOT National Transportation Integrated Search

    1988-04-01

    The Huntsville Volunteer Van Demonstration, operational since November of 1980, provides transportation service to the traditional transit-dependent community in an unconventional way. The city of Huntsville is not served by a conventional public tra...

  6. The Selection of a Van Lift or a Scooter.

    ERIC Educational Resources Information Center

    Stevens, John H.

    1990-01-01

    This newsletter issue describes 3-wheeled scooters and van lifts that can assist a person with a disability to drive independently or have access to transportation. The section on van lifts compares hydraulic lifts and electric lifts, lists manufacturers, and offers an "assessment quiz" outlining factors to consider in selecting a van…

  7. Thickened boundary layer theory for air film drag reduction on a van body surface

    NASA Astrophysics Data System (ADS)

    Xie, Xiaopeng; Cao, Lifeng; Huang, Heng

    2018-05-01

    To elucidate drag reduction mechanism on a van body surface under air film condition, a thickened boundary layer theory was proposed and a frictional resistance calculation model of the van body surface was established. The frictional resistance on the van body surface was calculated with different parameters of air film thickness. In addition, the frictional resistance of the van body surface under the air film condition was analyzed by computational fluid dynamics (CFD) simulation and different air film states that influenced the friction resistance on the van body surface were discussed. As supported by the CFD simulation results, the thickened boundary layer theory may provide reference for practical application of air film drag reduction on a van body surface.

  8. Pythagoras Meets Van Hiele.

    ERIC Educational Resources Information Center

    Flores, Alfinio

    1993-01-01

    Develops the Pythagorean Theorem in the context of the Van Hiele levels by presenting activities appropriate for each level. Activities point to preparatory development (level 0), give 3 different versions of Euclid's proof (levels 1, 2, and 3), give some generalizations of the theorem (level 3), and explore the Pythagorean relationship in other…

  9. Structural and Functional Adaptation of Vancomycin Resistance VanT Serine Racemases.

    PubMed

    Meziane-Cherif, Djalal; Stogios, Peter J; Evdokimova, Elena; Egorova, Olga; Savchenko, Alexei; Courvalin, Patrice

    2015-08-11

    Vancomycin resistance in Gram-positive bacteria results from the replacement of the D-alanyl-D-alanine target of peptidoglycan precursors with D-alanyl-D-lactate or D-alanyl-D-serine (D-Ala-D-Ser), to which vancomycin has low binding affinity. VanT is one of the proteins required for the production of D-Ala-D-Ser-terminating precursors by converting L-Ser to D-Ser. VanT is composed of two domains, an N-terminal membrane-bound domain, likely involved in L-Ser uptake, and a C-terminal cytoplasmic catalytic domain which is related to bacterial alanine racemases. To gain insight into the molecular function of VanT, the crystal structure of the catalytic domain of VanTG from VanG-type resistant Enterococcus faecalis BM4518 was determined. The structure showed significant similarity to type III pyridoxal 5'-phosphate (PLP)-dependent alanine racemases, which are essential for peptidoglycan synthesis. Comparative structural analysis between VanTG and alanine racemases as well as site-directed mutagenesis identified three specific active site positions centered around Asn696 which are responsible for the L-amino acid specificity. This analysis also suggested that VanT racemases evolved from regular alanine racemases by acquiring additional selectivity toward serine while preserving that for alanine. The 4-fold-lower relative catalytic efficiency of VanTG against L-Ser versus L-Ala implied that this enzyme relies on its membrane-bound domain for L-Ser transport to increase the overall rate of d-Ser production. These findings illustrate how vancomycin pressure selected for molecular adaptation of a housekeeping enzyme to a bifunctional enzyme to allow for peptidoglycan remodeling, a strategy increasingly observed in antibiotic-resistant bacteria. Vancomycin is one of the drugs of last resort against Gram-positive antibiotic-resistant pathogens. However, bacteria have evolved a sophisticated mechanism which remodels the drug target, the D-alanine ending precursors in cell wall

  10. REMOTE LAND MINE(FIELD) DETECTION. An Overview of Techniques (DETECTIE VAN LANDMIJNEN EN MIJNENVELDEN OP AFSTAND. Een Overzicht van de technieken),

    DTIC Science & Technology

    1994-09-01

    titel DETECTIE VAN LANDMIJNEN EN MIJNENVELDEN OP AFSTAND, een overzicht van de technieken auteur (s) Drs. J.S. Groot, Ir. Y.H.L. Janssen datum september...functions based on set theory . The fundamental theory is developed in the sixties. This theory was applicable to binary images (black-and-white images...held at TNO-FEL. Various subjects related to fusion techniques: Dempster Shafer theory , Bayesian inference, Kalman filtering, fuzzy logic. [A15], [B4

  11. Evolution of alkaline lakes - Lake Van case study

    NASA Astrophysics Data System (ADS)

    Tillman Meyer, Felix; Viehberg, Finn; Bahroun, Sonya; Wolf, Annabel; Immenhauser, Adrian; Kwiecien, Ola

    2017-04-01

    Lake Van in Eastern Anatolia (Turkey) is the largest terminal soda lake on Earth. The lake sedimentary profile covers ca. 600 ka (Stockhecke et al. 2014) Based on lithological changes, the presence of freshwater microfossils and close-to-freshwater pH value in the pore water, members of ICDP PALEOVAN concluded that Lake Van might have started as an open lake. Here we show paleontological and geochemical evidence in favour of this idea and constrain the time, when Lake Van likely transformed into a closed lake. Additionally we provide the first conceptual model of how this closure may have happened. Our archives of choice are inorganic and biogenic carbonates, separated by wet sieving. We identified microfossil assemblages (fraction > 125 µm) and performed high-resolution oxygen isotope (delta18O) and elemental (Mg/Ca, Sr/Ca) analyses of the fraction < 63 µm assuming that it represents only carbonates precipitating in the water column. Microfossil assemblage consists of three different species of ostracods (Candona spp, Loxoconcha sp, Amnicythere spp.), diatoms, gastropods and bivalves. Brakish-water ostracods, Loxoconcha sp and Amnicythere sp occur more often after 530 ka. Additionaly, Loxoconcha sp is a shallow-water species relaying on plants growing in the photic zone as food supply. These two aspects point to an increasing salinity in a shallowing lake. The delta18O values of inorganic carbonates are relatively low during the initial phase of Lake Van and increase abruptly (ca. 7‰) after 530 ka BP. At approximately the same time combination of Sr/Ca and Mg/Ca data suggest first occurrence of aragonite. Again, these findings suggest geochemical changes of the lake water concurrent with transition documented by microfossils. Comparison between Lake Van and Lake Ohrid (Lacey et al. 2016) delta18O data, precludes regional climate change (e.g.: increased evaporation) as the main driver of observed changes. With no evidence for increased volcanic or tectonic

  12. Combination Vancomycin/Cefazolin (VAN/CFZ) for Methicillin-Resistant Staphylococcus aureus (MRSA) Bloodstream Infections (BSI)

    PubMed Central

    Trinh, Trang D; Zasowski, Evan J; Lagnf, Abdalhamid M; Bhatia, Sahil; Dhar, Sorabh; Mynatt, Ryan; Pogue, Jason M; Rybak, Michael J

    2017-01-01

    Abstract Background VAN remains the standard for MRSA BSI but has been associated with treatment failures and resulted in prolonged BSI durations and recurrences. In vitro studies of VAN/CFZ against MRSA demonstrated synergy and prevention of VAN resistance. However, clinical use of VAN/CFZ has not been reported. The objective of this study was to compare patient outcomes treated with VAN/CFZ vs. VAN for MRSA BSI. Methods This was a retrospective, cohort, comparative-effectiveness study of hospitalized adults ≥18y with ≥1 MRSA blood culture and received VAN/CFZ combination for ≥24h or VAN alone initiated within 72h of index infection between 1/1/08 and 5/1/17. Patients who received >24h β-lactams other than CFZ, MRSA-active antibiotics other than VAN, with polymicrobial BSI, or had a second MRSA BSI episode during the study period were excluded. The primary composite failure outcome included: 30d mortality, MRSA BSI ≥7d, and 60d recurrence. Demographics were compared by Χ2, Fisher’s exact, Student’s t, or Mann–Whitney U tests. Multivariable regression models compared outcomes between the two treatment groups. Covariates with p-values ≤0.2 in bivariate analyses were included in the model. Results A total of 101 patients were included (CFZ/VAN = 41, VAN = 60). Demographics were similar except VAN patients were older (mean (±SD) age 58 (±14) v. 51 (±18) y, P = 0.04), had higher median (IQR) Charlson Comorbidity Index (3 (2-5) v. 1 (0–4), P < 0.01), APACHE II scores (13 (8-18) v. 11 (8-18), P = 0.2), and more endocarditis BSI source (37% v. 20%, P = 0.06). After accounting for BSI source, VAN/CFZ (adjusted odds ratio [aOR], 95% confidence intervals [CI], 0.33, 0.13-0.83) and low APACHE II scores (aOR 1.07, 95% CI 1–1.15) were independently associated with fewer failures. Bivariate outcomes are in table below: Variable, n (%) VAN/CFZ VAN P value Composite failure 10 (24) 31 (52) 0.006 30d mortality 3 (7.3) 5 (8.3) 1 BSI ≥7d 6 (15

  13. Detection of seasonal asymptomatic dermatophytes in Van cats.

    PubMed

    Ilhan, Ziya; Karaca, Mehmet; Ekin, Ismail Hakki; Solmaz, Hasan; Akkan, Hasan Altan; Tutuncu, Mehmet

    2016-01-01

    The Van cat is a domestic landrace found in the Van province of eastern Turkey. In this study, we aimed to determine the seasonal carriage of dermatophytes in Van cats without clinical lesions. A total of 264 hair specimens were collected from clinically healthy cats in and around the Van Province. Of these samples, 30.3% were obtained in spring, 30.6% in summer, 16.6% in autumn, and 22.3% in winter; 45.1% of samples were from male cats and the rest from female ones. Of the studied cats, 118 were younger than 1 year, 78 were 1-3 years old, and 68 were older than 3 years. The specimens were subjected to direct microscopic examination with 15% potassium hydroxide and cultured on Sabouraud dextrose agar and dermatophyte test medium supplemented with cycloheximide and chloramphenicol. Dermatophyte identification was carried out based on macroscopic and microscopic colony morphology, urease activities, in vitro hair perforation test, growth at 37°C, and pigmentation on corn meal agar. Dermatophytes were isolated from 19 (7.1%) of the 264 specimens examined. The most frequently isolated fungi were Trichophyton terrestre (4.1%), followed by Microsporum gypseum (1.1%), M. nanum (1.1%), and T. mentagrophytes (0.7%), and these fungi may represent a health risk for humans in contact with clinically healthy Van cats. M. canis was not isolated from any of the specimens. Our results show no significant (p>0.05) association between carriage of dermatophytes and the gender of cats. The carriage rate of dermatophytes was high in spring and winter, and the only possible risk factor for infection was age of the animal. Copyright © 2015 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

  14. New Results About the Earth’s Van Allen Radiation Belts

    NASA Astrophysics Data System (ADS)

    Baker, Daniel

    2015-01-01

    The first great scientific discovery of the Space Age was that the Earth is enshrouded in toroids, or 'belts', of very high-energy magnetically trapped charged particles. Early observations of the radiation environment clearly indicated that the Van Allen belts could be delineated into an inner zone dominated by high-energy protons and an outer zone dominated by high-energy electrons. Subsequent studies showed that electrons in the energy range 100 keV < E< 1 MeV often populated both the inner and outer zones with a pronounced 'slot' region relatively devoid of energetic electrons existing between them. This two-belt structure for the Van Allen moderate-energy electron component was explained as being due to strong interactions of electrons with electromagnetic waves just inside the cold plasma (plasmapause) boundary. The energy distribution, spatial extent and particle species makeup of the Van Allen belts has been subsequently explored by several space missions. However, recent observations by the NASA dual-spacecraft Van Allen Probes mission have revealed wholly unexpected properties of the radiation belts, especially at highly relativistic (E > 2 MeV) and ultra-relativistic (E > 5 MeV) kinetic energies. In this presentation we show using high spatial and temporal resolution data from the Relativistic Electron-Proton Telescope (REPT) experiment on board the Van Allen Probes that multiple belts can exist concurrently and that an exceedingly sharp inner boundary exists for ultra-relativistic electrons. Using additionally available Van Allen Probes data, we demonstrate that these remarkable features of energetic electrons are not due to a physical boundary within Earth's intrinsic magnetic field. Neither is it likely that human-generated electromagnetic transmitter wave fields might produce such effects. Rather, we conclude from these unique measurements that slow natural inward radial diffusion combined with weak, but persistent, wave-particle pitch angle

  15. Otto Van Geet | NREL

    Science.gov Websites

    Center at NREL. Otto has been involved in the design, construction, and operation of energy efficient energy use campus and community design. Mr. Van Geet was one of the founding members of the Labs21 and assessment, passive solar building design, use of design tools, photovoltaic (PV) system design

  16. Enhanced Chiral Discriminatory van der Waals Interactions Mediated by Chiral Surfaces

    NASA Astrophysics Data System (ADS)

    Barcellona, Pablo; Safari, Hassan; Salam, A.; Buhmann, Stefan Yoshi

    2017-05-01

    We predict a discriminatory interaction between a chiral molecule and an achiral molecule which is mediated by a chiral body. To achieve this, we generalize the van der Waals interaction potential between two ground-state molecules with electric, magnetic, and chiral response to nontrivial environments. The force is evaluated using second-order perturbation theory with an effective Hamiltonian. Chiral media enhance or reduce the free interaction via many-body interactions, making it possible to measure the chiral contributions to the van der Waals force with current technology. The van der Waals interaction is discriminatory with respect to enantiomers of different handedness and could be used to separate enantiomers. We also suggest a specific geometric configuration where the electric contribution to the van der Waals interaction is zero, making the chiral component the dominant effect.

  17. Jacobus Schroeder van der Kolk (1797-1862): his resistance against materialism.

    PubMed

    Eling, P

    1998-07-01

    Schroeder van der Kolk is regarded as the founder of Dutch psychiatry and neurology. This paper describes his vitalistic views on the relation between body and soul, as formulated by him in a series of lectures. These lectures were intended to counteract the materialistic tendencies of some of Schroeder van der Kolk's French and German contemporaries. It is argued that Schroeder van der Kolk can be regarded as the transition in Holland from the "Naturphilosophie" approach to the modern experimental approach in physiology. Copyright 1998 Academic Press.

  18. Fundacion Bernard van Leer, Boletin Informativo, 1987-1996 (Bernard van Leer Foundation Information Bulletin).

    ERIC Educational Resources Information Center

    Fundacion Bernard van Leer, Boletin Informativo, 1996

    1996-01-01

    This document consists of ten annual Spanish Language Bulletins, published during the period 1987-1996. The early bulletins were largely composed of selections originally published in the Bernard van Lear Foundation's English-Language "Newsletter The articles discuss topics such as: (1) parents as children's first teachers; (2) health and…

  19. Biochemical and Genetic Characterization of the vanC-2 Vancomycin Resistance Gene Cluster of Enterococcus casseliflavus ATCC 25788

    PubMed Central

    Dutta, Ireena; Reynolds, Peter E.

    2002-01-01

    The vanC-2 cluster of Enterococcus casseliflavus ATCC 25788 consisted of five genes (vanC-2, vanXYC-2, vanTC-2, vanRC-2, and vanSC-2) and shared the same organization as the vanC cluster of E. gallinarum BM4174. The proteins encoded by these genes displayed a high degree of amino acid identity to the proteins encoded within the vanC gene cluster. The putative d,d-dipeptidase-d,d-carboxypeptidase, VanXYC-2, exhibited 81% amino acid identity to VanXYC, and VanTC-2 displayed 65% amino acid identity to the serine racemase, VanT. VanRC-2 and VanSC-2 displayed high degrees of identity to VanRC and VanSC, respectively, and contained the conserved residues identified as important to their function as a response regulator and histidine kinase, respectively. Resistance to vancomycin was expressed inducibly in E. casseliflavus ATCC 25788 and required an extended period of induction. Analysis of peptidoglycan precursors revealed that UDP-N-acetylmuramyl-l-Ala-δ-d-Glu-l-Lys-d-Ala-d-Ser could not be detected until several hours after the addition of vancomycin, and its appearance coincided with the resumption of growth. The introduction of additional copies of the vanTC-2 gene, encoding a putative serine racemase, and the presence of supplementary d-serine in the growth medium both significantly reduced the period before growth resumed after addition of vancomycin. This suggested that the availability of d-serine plays an important role in the induction process. PMID:12234834

  20. The first report of the vanC₁ gene in Enterococcus faecium isolated from a human clinical specimen.

    PubMed

    Sun, Mingyue; Wang, Yue; Chen, Zhongju; Zhu, Xuhui; Tian, Lei; Sun, Ziyong

    2014-09-01

    The vanC₁ gene, which is chromosomally located, confers resistance to vancomycin and serves as a species marker for Enterococcus gallinarum. Enterococcus faecium TJ4031 was isolated from a blood culture and harbours the vanC₁gene. Polymerase chain reaction (PCR) assays were performed to detect vanXYc and vanTc genes. Only the vanXYc gene was found in the E. faecium TJ4031 isolate. The minimum inhibitory concentrations of vancomycin and teicoplanin were 2 µg/mL and 1 µg/mL, respectively. Real-time reverse transcription-PCR results revealed that the vanC₁ and vanXYc genes were not expressed. Pulsed-field gel electrophoresis and southern hybridisation results showed that the vanC₁ gene was encoded in the chromosome. E. faecalis isolated from animals has been reported to harbour vanC₁gene. However, this study is the first to report the presence of the vanC₁gene in E. faecium of human origin. Additionally, our research showed the vanC₁gene cannot serve as a species-specific gene of E. gallinarum and that it is able to be transferred between bacteria. Although the resistance marker is not expressed in the strain, our results showed that E. faecium could acquire the vanC₁gene from different species.

  1. NASA's Van Allen Probes Discover a Surprise Circling Earth

    NASA Image and Video Library

    2017-12-08

    Two giant swaths of radiation, known as the Van Allen Belts, surrounding Earth were discovered in 1958. In 2012, observations from the Van Allen Probes showed that a third belt can sometimes appear. The radiation is shown here in yellow, with green representing the spaces between the belts. Credit: NASA/Van Allen Probes/Goddard Space Flight Center To read more go to: www.nasa.gov/mission_pages/rbsp/news/third-belt.html NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

  2. Bernard van Leer Foundation Annual Review 1993 = Fundacion Bernard van Leer Revista Anual 1993.

    ERIC Educational Resources Information Center

    Bernard Van Leer Foundation, The Hague (Netherlands).

    This report, in both English and Spanish versions, aims to highlight the Bernard van Leer Foundation's identity, objectives, and major activities, as well as the work undertaken by the projects the foundation supports. The review features articles on the Foundation's work on advocacy, supporting families living in disadvantaged circumstances,…

  3. Biochemical and genetic characterization of the vanC-2 vancomycin resistance gene cluster of Enterococcus casseliflavus ATCC 25788.

    PubMed

    Dutta, Ireena; Reynolds, Peter E

    2002-10-01

    The vanC-2 cluster of Enterococcus casseliflavus ATCC 25788 consisted of five genes (vanC-2, vanXY(C-2), vanT(C-2), vanR(C-2), and vanS(C-2)) and shared the same organization as the vanC cluster of E. gallinarum BM4174. The proteins encoded by these genes displayed a high degree of amino acid identity to the proteins encoded within the vanC gene cluster. The putative D,D-dipeptidase-D,D-carboxypeptidase, VanXY(C-2), exhibited 81% amino acid identity to VanXY(C), and VanT(C-2) displayed 65% amino acid identity to the serine racemase, VanT. VanR(C-2) and VanS(C-2) displayed high degrees of identity to VanR(C) and VanS(C), respectively, and contained the conserved residues identified as important to their function as a response regulator and histidine kinase, respectively. Resistance to vancomycin was expressed inducibly in E. casseliflavus ATCC 25788 and required an extended period of induction. Analysis of peptidoglycan precursors revealed that UDP-N-acetylmuramyl-L-Ala-delta-D-Glu-L-Lys-D-Ala-D-Ser could not be detected until several hours after the addition of vancomycin, and its appearance coincided with the resumption of growth. The introduction of additional copies of the vanT(C-2) gene, encoding a putative serine racemase, and the presence of supplementary D-serine in the growth medium both significantly reduced the period before growth resumed after addition of vancomycin. This suggested that the availability of D-serine plays an important role in the induction process.

  4. First and Second Order Stokes Generation by SRS in Methane: Influence of Rep-Rate, Beam Quality and Astigmatism (Opwekking van Eerste en Tweede Orde Stokes d.m.v. SRS in Methaan: Invloed van de Pulsfrequentie, de Bundelkwaliteit en Astigmatisme)

    DTIC Science & Technology

    1992-09-01

    omzettings rendementen van circa 75% gehaad bij een ingangs- energie van 280 mJ. De mogelijkheden tot bet halen van een hoger rendement lijken...of rep-rate, beam quality and astigmatism DImi-Thu-B~mO ITA1EiM-tT-h lF I~~ ~~’ IAPR2 8 1993~ I ~Xtbai Uiitdw FJ.M. van Putten J.C. van den Heuvel RJ.L...Influence of rep-rate. beam quality and astigmatism author(s) : F.J.M. van Putten, I.C. van den Heuvel, R.J.L. Lerou institute : TNO Physics and

  5. Van Kampen Colimits as Bicolimits in Span

    NASA Astrophysics Data System (ADS)

    Heindel, Tobias; Sobociński, Paweł

    The exactness properties of coproducts in extensive categories and pushouts along monos in adhesive categories have found various applications in theoretical computer science, e.g. in program semantics, data type theory and rewriting. We show that these properties can be understood as a single universal property in the associated bicategory of spans. To this end, we first provide a general notion of Van Kampen cocone that specialises to the above colimits. The main result states that Van Kampen cocones can be characterised as exactly those diagrams in ℂ that induce bicolimit diagrams in the bicategory of spans mathcal{S}pan_{mathbb{C}}, provided that ℂ has pullbacks and enough colimits.

  6. Flower Still Life, Maria Van Oosterwijck

    ERIC Educational Resources Information Center

    Holtrop, Emily

    2004-01-01

    This brief article describes the life of Maria van Oosterwijck. It also discusses her art and its significance and symbolism. A list of suggested activities for elementary, middle, and high school students is included.

  7. Experimental Testing of a Van De Graaff Generator as an Electromagnetic Pulse Generator

    DTIC Science & Technology

    2016-07-01

    EXPERIMENTAL TESTING OF A VAN DE GRAAFF GENERATOR AS AN ELECTROMAGNETIC PULSE GENERATOR THESIS...protection in the United States AFIT-ENP-MS-16-S-075 EXPERIMENTAL TESTING OF A VAN DE GRAAFF GENERATOR AS AN ELECTROMAGNETIC PULSE GENERATOR...RELEASE; DISTRIBUTION UNLIMITED. AFIT-ENP-MS-16-S-075 EXPERIMENTAL TESTING OF A VAN DE GRAAFF GENERATOR AS AN ELECTROMAGNETIC PULSE GENERATOR

  8. Aldo van Eyck’s Playgrounds: Aesthetics, Affordances, and Creativity

    PubMed Central

    Withagen, Rob; Caljouw, Simone R.

    2017-01-01

    After World War II, the Dutch architect Aldo van Eyck developed hundreds of playgrounds in the city of Amsterdam. These public playgrounds were located in parks, squares, and derelict sites, and consisted of minimalistic aesthetic play equipment that was supposed to stimulate the creativity of children. Over the last decades, these playgrounds have been studied by sociologists, theorists of art and architecture, and psychologists. Adopting an ecological approach to the human environment, it is argued that the abstract forms of van Eyck’s play sculptures indeed stimulate the creativity of the child. Whereas a slide or a swing almost dictates what a child is supposed to do, van Eyck’s play equipment invites the child to actively explore the numerous affordances (action possibilities) it provided. However, it is argued that the standardization (e.g., equal distances between blocks or bars) that tends to characterize van Eyck’ play equipment has negative effects on the playability. This standardization, which was arguably the result of the aesthetic motives of the designer, might be appealing to children when simply looking at the equipment, but it is not of overriding importance to them when playing in it. Indeed, a recent study indicates that the affordances provided by messy structures appear to have a greater appeal to playing children. PMID:28725208

  9. d-Ala-d-Ser VanN-Type Transferable Vancomycin Resistance in Enterococcus faecium▿

    PubMed Central

    Lebreton, François; Depardieu, Florence; Bourdon, Nancy; Fines-Guyon, Marguerite; Berger, Pierre; Camiade, Sabine; Leclercq, Roland; Courvalin, Patrice; Cattoir, Vincent

    2011-01-01

    Enterococcus faecium UCN71, isolated from a blood culture, was resistant to low levels of vancomycin (MIC, 16 μg/ml) but susceptible to teicoplanin (MIC, 0.5 μg/ml). No amplification was observed with primers specific for the previously described glycopeptide resistance ligase genes, but a PCR product corresponding to a gene called vanN was obtained using degenerate primers and was sequenced. The deduced VanN protein was related (65% identity) to the d-alanine:d-serine VanL ligase. The organization of the vanN gene cluster, determined using degenerate primers and by thermal asymmetric interlaced (TAIL)-PCR, was similar to that of the vanC operons. A single promoter upstream from the resistance operon was identified by rapid amplification of cDNA ends (RACE)-PCR. The presence of peptidoglycan precursors ending in d-serine and d,d-peptidase activities in the absence of vancomycin indicated constitutive expression of the resistance operon. VanN-type resistance was transferable by conjugation to E. faecium. This is the first report of transferable d-Ala-d-Ser-type resistance in E. faecium. PMID:21807981

  10. Quantum synchronization of quantum van der Pol oscillators with trapped ions.

    PubMed

    Lee, Tony E; Sadeghpour, H R

    2013-12-06

    The van der Pol oscillator is the prototypical self-sustained oscillator and has been used to model nonlinear behavior in biological and other classical processes. We investigate how quantum fluctuations affect phase locking of one or many van der Pol oscillators. We find that phase locking is much more robust in the quantum model than in the equivalent classical model. Trapped-ion experiments are ideally suited to simulate van der Pol oscillators in the quantum regime via sideband heating and cooling of motional modes. We provide realistic experimental parameters for 171Yb+ achievable with current technology.

  11. Colossal terahertz nonlinearity of tunneling van der Waals gap (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Bahk, Young-Mi; Kang, Bong Joo; Kim, Yong Seung; Kim, Joon-Yeon; Kim, Won Tae; Kim, Tae Yun; Kang, Taehee; Rhie, Ji Yeah; Han, Sanghoon; Park, Cheol-Hwan; Rotermund, Fabian; Kim, Dai-Sik

    2016-09-01

    We manufactured an array of three angstrom-wide, five millimeter-long van der Waals gaps of copper-graphene-copper composite, in which unprecedented nonlinearity was observed. To probe and manipulate van der Waals gaps with long wavelength electromagnetic waves such as terahertz waves, one is required to fabricate vertically oriented van der Waals gaps sandwiched between two metal planes with an infinite length in the sense of being much larger than any of the wavelengths used. By comparison with the simple vertical stacking of metal-graphene-metal structure, in our structure, background signals are completely blocked enabling all the light to squeeze through the gap without any strays. When the angstrom-sized van der Waals gaps are irradiated with intense terahertz pulses, the transient voltage across the gap reaches up to 5 V with saturation, sufficiently strong to deform the quantum barrier of angstrom gaps. The large transient potential difference across the gap facilitates electron tunneling through the quantum barrier, blocking terahertz waves completely. This negative feedback of electron tunneling leads to colossal nonlinear optical response, a 97% decrease in the normalized transmittance. Our technology for infinitely long van der Waals gaps can be utilized for other atomically thin materials than single layer graphene, enabling linear and nonlinear angstrom optics in a broad spectral range.

  12. Application of Diffusion Monte Carlo to Materials Dominated by van der Waals Interactions

    DOE PAGES

    Benali, Anouar; Shulenburger, Luke; Romero, Nichols A.; ...

    2014-06-12

    Van der Waals forces are notoriously difficult to account for from first principles. We perform extensive calculation to assess the usefulness and validity of diffusion quantum Monte Carlo when applied to van der Waals forces. We present results for noble gas solids and clusters - archetypical van der Waals dominated assemblies, as well as a relevant pi-pi stacking supramolecular complex: DNA + intercalating anti-cancer drug Ellipticine.

  13. Heterologous expression of glycopeptide resistance vanHAX gene clusters from soil bacteria in Enterococcus faecalis.

    PubMed

    Hasman, Henrik; Aarestrup, Frank M; Dalsgaard, Anders; Guardabassi, Luca

    2006-04-01

    The aim of the study was to determine whether glycopeptide resistance gene clusters from soil bacteria could be heterologously expressed in Enterococcus faecalis and adapt to the new host following exposure to vancomycin. The vanHAX clusters from Paenibacillus thiaminolyticus PT-2B1, Paenibacillus apiarius PA-B2B and Amycolatopsis coloradensis DSM 44225 were separately cloned in an appropriately constructed shuttle vector containing the two-component regulatory system (vanRS) of Tn1546. The complete vanA(PT) operon (vanRSHAXY) from P. thiaminolyticus PT-2B1 was cloned in the same shuttle vector lacking enterococcal vanRS. All plasmid constructs were electroporated into E. faecalis JH2-2 and the MICs of vancomycin and teicoplanin were determined for each recombinant strain before and following exposure to sublethal concentrations of vancomycin. The vanHAX clusters from P. thiaminolyticus and P. apiarius conferred high-level vancomycin resistance (MIC > or = 125 mg/L) in E. faecalis JH2-2. In contrast, cloning of the vanHAX cluster from A. coloradensis did not result in a significant increase of vancomycin resistance (MIC = 0.7 mg/L). Resistance to vancomycin was not observed after cloning the complete vanA(PT) operon from P. thiaminolyticus (MIC = 2 mg/L), but this recombinant rapidly adapted to high concentrations of vancomycin (MIC = 500 mg/L) following exposure to sub-lethal concentrations of this antibiotic. The results showed that vanA(PT) in P. thiaminolyticus is a possible ancestor of vanA-mediated glycopeptide resistance in enterococci. Experimental evidence supported the hypothesis that enterococci did not acquire glycopeptide resistance directly from glycopeptide-producing organisms such as A. coloradensis.

  14. Cosmological models constructed by van der Waals fluid approximation and volumetric expansion

    NASA Astrophysics Data System (ADS)

    Samanta, G. C.; Myrzakulov, R.

    The universe modeled with van der Waals fluid approximation, where the van der Waals fluid equation of state contains a single parameter ωv. Analytical solutions to the Einstein’s field equations are obtained by assuming the mean scale factor of the metric follows volumetric exponential and power-law expansions. The model describes a rapid expansion where the acceleration grows in an exponential way and the van der Waals fluid behaves like an inflation for an initial epoch of the universe. Also, the model describes that when time goes away the acceleration is positive, but it decreases to zero and the van der Waals fluid approximation behaves like a present accelerated phase of the universe. Finally, it is observed that the model contains a type-III future singularity for volumetric power-law expansion.

  15. Crater Wall in Van de Graaff

    NASA Image and Video Library

    2010-02-11

    This image taken NASA Lunar Reconnaissance Orbiter shows the wall of crater Van de Graaff C, where brighter material is exposed by more active processes associated with steeper slopes, recent small craters, and even individual rolling boulders.

  16. Polyclonal emergence of vanA vancomycin-resistant Enterococcus faecium in Australia.

    PubMed

    van Hal, Sebastiaan J; Espedido, Björn A; Coombs, Geoffrey W; Howden, Benjamin P; Korman, Tony M; Nimmo, Graeme R; Gosbell, Iain B; Jensen, Slade O

    2017-04-01

    To investigate the genetic context associated with the emergence of vanA VRE in Australia. The whole genomes of 18 randomly selected vanA -positive Enterococcus faecium patient isolates, collected between 2011 and 2013 from hospitals in four Australian capitals, were sequenced and analysed. In silico typing and transposon/plasmid assembly revealed that the sequenced isolates represented (in most cases) different hospital-adapted STs and were associated with a variety of different Tn 1546 variants and plasmid backbone structures. The recent emergence of vanA VRE in Australia was polyclonal and not associated with the dissemination of a single 'dominant' ST or vanA -encoding plasmid. Interestingly, the factors contributing to this epidemiological change are not known and future studies may need to consider investigation of potential community sources. © The Author 2016. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  17. Storings analyse Ten Behoeve van het Materieelverzorgingsplan (Failure Analysis for the Maintenance Plan)

    DTIC Science & Technology

    1990-05-01

    oporachtnemer verwezen naar de ’Algemone Voorwaarden voor Onderzoeks- opdrachten TNO’. dan wet de betreflende terzake fijasen partlijen gesloten * 11 ...ixvulling van het onderhoudsschema 9 2.4 Invulling van het onderhoudsschema in de praktijk 14 2.5 Gonclusies 16 3 STORINGSANALYSES 18 3.1 ’Failure mode...nnfd- en subgroep (dit is een opdeling van bet systeem naar functioneel sanienhangende delen). Pa gina 9 - Het onderhoudsniveau waar jedere

  18. Theory of coherent van der Waals matter.

    PubMed

    Kulić, Igor M; Kulić, Miodrag L

    2014-12-01

    We explain in depth the previously proposed theory of the coherent van der Waals (cvdW) interaction, the counterpart of van der Waals (vdW) force, emerging in spatially coherently fluctuating electromagnetic fields. We show that cvdW driven matter is dominated by many-body interactions, which are significantly stronger than those found in standard van der Waals (vdW) systems. Remarkably, the leading two- and three-body interactions are of the same order with respect to the distance (∝R(-6)), in contrast to the usually weak vdW three-body effects (∝R(-9)). From a microscopic theory we show that the anisotropic cvdW many-body interactions drive the formation of low-dimensional structures such as chains, membranes, and vesicles with very unusual, nonlocal properties. In particular, cvdW chains display a logarithmically growing stiffness with the chain length, while cvdW membranes have a bending modulus growing linearly with their size. We argue that the cvdW anisotropic many-body forces cause local cohesion but also a negative effective "surface tension." We conclude by deriving the equation of state for cvdW materials and propose experiments to test the theory, in particular the unusual three-body nature of cvdW.

  19. Theory of coherent van der Waals matter

    NASA Astrophysics Data System (ADS)

    Kulić, Igor M.; Kulić, Miodrag L.

    2014-12-01

    We explain in depth the previously proposed theory of the coherent van der Waals (cvdW) interaction, the counterpart of van der Waals (vdW) force, emerging in spatially coherently fluctuating electromagnetic fields. We show that cvdW driven matter is dominated by many-body interactions, which are significantly stronger than those found in standard van der Waals (vdW) systems. Remarkably, the leading two- and three-body interactions are of the same order with respect to the distance (∝R-6) , in contrast to the usually weak vdW three-body effects (∝R-9 ). From a microscopic theory we show that the anisotropic cvdW many-body interactions drive the formation of low-dimensional structures such as chains, membranes, and vesicles with very unusual, nonlocal properties. In particular, cvdW chains display a logarithmically growing stiffness with the chain length, while cvdW membranes have a bending modulus growing linearly with their size. We argue that the cvdW anisotropic many-body forces cause local cohesion but also a negative effective "surface tension." We conclude by deriving the equation of state for cvdW materials and propose experiments to test the theory, in particular the unusual three-body nature of cvdW.

  20. van Maanen, Adriaan (1884-1947)

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    Dutch astronomer, became a member of the Mount Wilson staff, and studied the rotation of spiral nebulae as a means to establish their distances. His detection of rotational motions was illusory and misleadingly suggested that they were relatively nearby. Through its proper motion and parallax, he discovered the white dwarf van Maanen's star....

  1. A revision of the tribe Planitorini van Achterberg (Hymenoptera, Braconidae, Euphorinae), with description of a new genus from Australia.

    PubMed

    van Achterberg, Cornelis; Quicke, Donald L J; Boring, C Andrew

    2017-01-01

    The tribe Planitorini van Achterberg (Hymenoptera: Braconidae: Euphorinae) is revised. One new genus Paramannokeraia gen. n. (type species: P. gibsoni sp. n. ) and five new species from Australia are described and illustrated: Mannokeraia albipalpis van Achterberg, sp. n. , M. nigrita van Achterberg, sp. n. , M. punctata van Achterberg, sp. n. , Paramannokeraia gibsoni van Achterberg & Quicke, sp. n. and P. juliae van Achterberg, sp. n. The tribe Mannokeraiini van Achterberg, 1995, is synonymized with the tribe Planitorini ( syn. n. ).

  2. Astrobiology as a tool for getting high school students interested in science

    NASA Astrophysics Data System (ADS)

    Van der Meer, B. W.; Alletto, James J.; Bryant, Dudley; Carini, Mike; Elliott, Larry; Gelderman, Richard; Mason, Wayne; McDaniel, Kerrie; McGruder, Charles H.; Rinehart, Claire; Tyler, Rico; Walker, Linda

    2000-12-01

    A workshop was held (10/99) for high school students and teachers on astrobiology. NASA provided support through an IDEAS grant. Out of 63 qualified applicants, 29 were accepted: 22 students (11 minorities) and 7 teachers. The worship was held on 2 successive weekends. Activities included: culturing microbes from human skin, discussing 'what is life?', building and using a 2-inch refractive telescope and a van-Leeuwenhoek- type microscope (each participant built and kept them), listening to lectures by Dr. Richard Gelderman on detecting extra solar planets and by Dr. Richard Hoover on life in extreme environments. Other activities included: collecting samples and isolating micro-organisms from the lost river cave, studying microbial life from extreme environments in the laboratory, using the internet as a research tool and debating the logistics and feasibility of a lunar colony. Written evaluations of the workshop led to the following conclusions: 48% of the students considered a possible career in the biological and/or astrophysical sciences, and half of these stated they were spurred on by the workshop itself.

  3. Science, Sex, and Pictures: Reflections on Van Fraassen's Use of Perspectival Representations

    NASA Astrophysics Data System (ADS)

    Okruhlik, Kathleen

    2014-03-01

    Bas van Fraassen's brand of empiricism, as articulated in his well-known constructive empiricism and his more recent empiricist structuralism, has been developed using the so-called semantic approach to scientific theories. This approach has allowed van Fraassen to espouse quite a robust form of non-realism about unobservable entities while avoiding some of the problems that contributed to the demise of logical empiricism. I shall argue, however, that in other respects van Fraassen replicates many of the serious shortcomings associated with the earlier tradition -- despite the fact that his choice of language sometimes obscures those similarities. Because van Fraassen's empiricist structuralism is much less well-known than his constructive empiricism, the rather lengthy first section of this paper provides an overview and initial assessment of that position. Subsequent sections deal with the ways in which van Fraassen's very sophisticated form of empiricism not only fails to address some of the most serious shortcomings of logical empiricism but actually reinforces them. The chief focus is on the failure to address issues that arise from the historical and social contexts within which science is pursued -- this despite a vocabulary rich in references to perspectivity, pragmatics, context, use, and aims.

  4. A revision of the tribe Planitorini van Achterberg (Hymenoptera, Braconidae, Euphorinae), with description of a new genus from Australia

    PubMed Central

    van Achterberg, Cornelis; Quicke, Donald L.J.; Boring, C. Andrew

    2017-01-01

    Abstract The tribe Planitorini van Achterberg (Hymenoptera: Braconidae: Euphorinae) is revised. One new genus Paramannokeraia gen. n. (type species: P. gibsoni sp. n.) and five new species from Australia are described and illustrated: Mannokeraia albipalpis van Achterberg, sp. n., M. nigrita van Achterberg, sp. n., M. punctata van Achterberg, sp. n., Paramannokeraia gibsoni van Achterberg & Quicke, sp. n. and P. juliae van Achterberg, sp. n. The tribe Mannokeraiini van Achterberg, 1995, is synonymized with the tribe Planitorini (syn. n.). PMID:29290713

  5. [Johann van Beethoven (1776-1848)].

    PubMed

    Eikermann, Erika

    2012-01-01

    The article about the life and achievements of the apothecary Johann van Beethoven, the younger brother of the composer Ludwig van Beethoven, depicts a vivid picture of life in the 18th, 19t century. Research on archived original documents in Bonn, Vienna and Linz on the Danube made it possible to reveal details about the relationship inside this famous family and describes the hurdles of life of a successful apothecary. In 1776 Johann van Beethoven was born as the fourth child of the Beethoven family, a family of Bonner musicians. In 1790 he began his apprenticeship to become an apothecary at the Bonner "Hofapotheke". Towards the end of 1795 he moved to join his older brothers Ludwig and Karl in Vienna. During his time there he worked as a "subject" in various Viennese pharmacies. However in 1808 he purchased the pharmacy "Zur Goldenen Krone" in Linz on the Danube. His new pharmacy flourished, supplying first the Napoleonic occupation troops, and later the Austrian Military with medicines and field dressing/bandage materials. When in 1812 he married his Housekeeper, his Brother Ludwig opposed harshly, on reasons of social status and on moral grounds. Four years later, in 1816 Johann sold the pharmacy in Linz and founded a new pharmacy in Urfahr, on the opposite bank of the Danube. In 1819 he became a squire (or landowner), when he purchased a manor estate in Gneixendorf, near Krems on the Danube. In spite of his numerous duties as an apothecary and squire, Johann was frequently resident in Vienna, supporting his brother both emotionally and pharmaceutically. At the end of his life Johann sold both his pharmacy and the Gneixendorf estate, and spent his last years as a private gentleman living a dazzling lifestyle in Vienna. He died on January 12th 1848 and was buried in Vienna's "Waldmüllerpark".

  6. Brown-Vialetto-Van Laere syndrome.

    PubMed

    Francis, D A; Ponsford, J R; Wiles, C M; Thomas, P K; Duchen, L W

    1993-02-01

    The clinical and pathological findings of a male with the Brown-Vialetto-Van Laere syndrome are described. This rare and fatal affection of the nervous system involves mainly the brain stem with the prominent and early manifestation of sensorineural deafness. Increased awareness and documentation of this disorder has added information on the mode of inheritance.

  7. Van vleck paramagnetism in orthorhombic TiO2 (Brookite)

    USGS Publications Warehouse

    Senftle, F.E.; Thorpe, A.N.

    1968-01-01

    The magnetic susceptibility of the orthorhombic form of titanium dioxide has been measured from 5 to 300??K. After deducting the temperature-dependent component, which is probably due to defects or impurities, and the free-ion diamagnetic component, the Van Vleck paramagnetism was estimated to be 33??10-6 emu/mole. Comparison is made between this value and the Van Vleck paramagnetism of strontium titanate and the two tetragonal forms of titanium dioxide: rutile and anatase. ?? 1968 The American Physical Society.

  8. Implication of Two-Coupled Differential Van der Pol Duffing Oscillator in Weak Signal Detection

    NASA Astrophysics Data System (ADS)

    Peng, Hang-hang; Xu, Xue-mei; Yang, Bing-chu; Yin, Lin-zi

    2016-04-01

    The principle of the Van der Pol Duffing oscillator for state transition and for determining critical value is described, which has been studied to indicate that the application of the Van der Pol Duffing oscillator in weak signal detection is feasible. On the basis of this principle, an improved two-coupled differential Van der Pol Duffing oscillator is proposed which can identify signals under any frequency and ameliorate signal-to-noise ratio (SNR). The analytical methods of the proposed model and the construction of the proposed oscillator are introduced in detail. Numerical experiments on the properties of the proposed oscillator compared with those of the Van der Pol Duffing oscillator are carried out. Our numerical simulations have confirmed the analytical treatment. The results demonstrate that this novel oscillator has better detection performance than the Van der Pol Duffing oscillator.

  9. Observation of van Hove Singularities in Twisted Silicene Multilayers

    PubMed Central

    2016-01-01

    Interlayer interactions perturb the electronic structure of two-dimensional materials and lead to new physical phenomena, such as van Hove singularities and Hofstadter’s butterfly pattern. Silicene, the recently discovered two-dimensional form of silicon, is quite unique, in that silicon atoms adopt competing sp2 and sp3 hybridization states leading to a low-buckled structure promising relatively strong interlayer interaction. In multilayer silicene, the stacking order provides an important yet rarely explored degree of freedom for tuning its electronic structures through manipulating interlayer coupling. Here, we report the emergence of van Hove singularities in the multilayer silicene created by an interlayer rotation. We demonstrate that even a large-angle rotation (>20°) between stacked silicene layers can generate a Moiré pattern and van Hove singularities due to the strong interlayer coupling in multilayer silicene. Our study suggests an intriguing method for expanding the tunability of the electronic structure for electronic applications in this two-dimensional material. PMID:27610412

  10. Observation of van Hove Singularities in Twisted Silicene Multilayers.

    PubMed

    Li, Zhi; Zhuang, Jincheng; Chen, Lan; Ni, Zhenyi; Liu, Chen; Wang, Li; Xu, Xun; Wang, Jiaou; Pi, Xiaodong; Wang, Xiaolin; Du, Yi; Wu, Kehui; Dou, Shi Xue

    2016-08-24

    Interlayer interactions perturb the electronic structure of two-dimensional materials and lead to new physical phenomena, such as van Hove singularities and Hofstadter's butterfly pattern. Silicene, the recently discovered two-dimensional form of silicon, is quite unique, in that silicon atoms adopt competing sp(2) and sp(3) hybridization states leading to a low-buckled structure promising relatively strong interlayer interaction. In multilayer silicene, the stacking order provides an important yet rarely explored degree of freedom for tuning its electronic structures through manipulating interlayer coupling. Here, we report the emergence of van Hove singularities in the multilayer silicene created by an interlayer rotation. We demonstrate that even a large-angle rotation (>20°) between stacked silicene layers can generate a Moiré pattern and van Hove singularities due to the strong interlayer coupling in multilayer silicene. Our study suggests an intriguing method for expanding the tunability of the electronic structure for electronic applications in this two-dimensional material.

  11. J. H. Van Vleck and Magnetism at the University of Wisconsin: 1928 -1934

    NASA Astrophysics Data System (ADS)

    Huber, David

    2011-03-01

    In 1928, John Van Vleck returned to his alma mater to take a position in the Physics Department. Six years later he left to join the faculty of Harvard University. While Van Vleck was at Wisconsin, he began a series of theoretical studies that helped lay the foundation for the modern theory of magnetism in solids. In 1932 Van Vleck published his celebrated monograph, The Theory of Electric and Magnetic Susceptibilities, in which he made use of the new theory to explain the results of experimental studies in a variety of magnetic materials. In my talk, I will review the accomplishments of Van Vleck and his students during this period and also comment briefly on his notes for a second edition of the book.

  12. Electromagnetic van Kampen waves

    SciTech Connect

    Ignatov, A. M., E-mail: aign@fpl.gpi.ru

    2017-01-15

    The theory of van Kampen waves in plasma with an arbitrary anisotropic distribution function is developed. The obtained solutions are explicitly expressed in terms of the permittivity tensor. There are three types of perturbations, one of which is characterized by the frequency dependence on the wave vector, while for the other two, the dispersion relation is lacking. Solutions to the conjugate equations allowing one to solve the initial value problem are analyzed.

  13. Spacecraft-level verification of the Van Allen Probes' RF communication system

    NASA Astrophysics Data System (ADS)

    Crowne, M. J.; Srinivasan, D.; Royster, D.; Weaver, G.; Matlin, D.; Mosavi, N.

    This paper presents the verification process, lessons learned, and selected test results of the radio frequency (RF) communication system of the Van Allen Probes, formerly known as the Radiation Belt Storm Probes (RBSP). The Van Allen Probes mission is investigating the doughnut-shaped regions of space known as the Van Allen radiation belts where the Sun interacts with charged particles trapped in Earth's magnetic field. Understanding this dynamic area that surrounds our planet is important to improving our ability to design spacecraft and missions for reliability and astronaut safety. The Van Allen Probes mission features two nearly identical spacecraft designed, built, and operated by the Johns Hopkins University Applied Physics Laboratory (JHU/APL) for the National Aeronautics and Space Administration (NASA). The RF communication system features the JHU/APL Frontier Radio. The Frontier Radio is a software-defined radio (SDR) designed for spaceborne communications, navigation, radio science, and sensor applications. This mission marks the first spaceflight usage of the Frontier Radio. RF ground support equipment (RF GSE) was developed using a ground station receiver similar to what will be used in flight and whose capabilities provided clarity into RF system performance that was previously not obtained until compatibility testing with the ground segments. The Van Allen Probes underwent EMC, acoustic, vibration, and thermal vacuum testing at the environmental test facilities at APL. During this time the RF communication system was rigorously tested to ensure optimal performance, including system-level testing down to threshold power levels. Compatibility tests were performed with the JHU/APL Satellite Communication Facility (SCF), the Universal Space Network (USN), and the Tracking and Data Relay Satellite System (TDRSS). Successful completion of this program as described in this paper validated the design of the system and demonstrated that it will be able to me

  14. Cylinders and Seances: Elise van Calcar and the Spirit of Froebel

    ERIC Educational Resources Information Center

    Bakker, Nelleke

    2013-01-01

    This essay discusses the life and work of Elise van Calcar (1822-1904), a writer and maternal feminist who introduced Froebel's kindergarten in the Netherlands. Van Calcar also was the leader of a Christian branch of spiritualism. The focus is pointed at parallels between her reading of Froebel and of "messages" from spirits in the…

  15. 15 CFR 30.26 - Reporting of vessels, aircraft, cargo vans, and other carriers and containers.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... vehicles, trailers, pallets, cargo vans, lift vans, or similar shipping containers are not considered... 15 Commerce and Foreign Trade 1 2014-01-01 2014-01-01 false Reporting of vessels, aircraft, cargo vans, and other carriers and containers. 30.26 Section 30.26 Commerce and Foreign Trade Regulations...

  16. 15 CFR 30.26 - Reporting of vessels, aircraft, cargo vans, and other carriers and containers.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... vehicles, trailers, pallets, cargo vans, lift vans, or similar shipping containers are not considered... 15 Commerce and Foreign Trade 1 2012-01-01 2012-01-01 false Reporting of vessels, aircraft, cargo vans, and other carriers and containers. 30.26 Section 30.26 Commerce and Foreign Trade Regulations...

  17. 15 CFR 30.26 - Reporting of vessels, aircraft, cargo vans, and other carriers and containers.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... vehicles, trailers, pallets, cargo vans, lift vans, or similar shipping containers are not considered... 15 Commerce and Foreign Trade 1 2013-01-01 2013-01-01 false Reporting of vessels, aircraft, cargo vans, and other carriers and containers. 30.26 Section 30.26 Commerce and Foreign Trade Regulations...

  18. 15 CFR 30.26 - Reporting of vessels, aircraft, cargo vans, and other carriers and containers.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... vehicles, trailers, pallets, cargo vans, lift vans, or similar shipping containers are not considered... 15 Commerce and Foreign Trade 1 2010-01-01 2010-01-01 false Reporting of vessels, aircraft, cargo vans, and other carriers and containers. 30.26 Section 30.26 Commerce and Foreign Trade Regulations...

  19. 15 CFR 30.26 - Reporting of vessels, aircraft, cargo vans, and other carriers and containers.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... vehicles, trailers, pallets, cargo vans, lift vans, or similar shipping containers are not considered... 15 Commerce and Foreign Trade 1 2011-01-01 2011-01-01 false Reporting of vessels, aircraft, cargo vans, and other carriers and containers. 30.26 Section 30.26 Commerce and Foreign Trade Regulations...

  20. Dynamical screening of the van der Waals interaction between graphene layers.

    PubMed

    Dappe, Y J; Bolcatto, P G; Ortega, J; Flores, F

    2012-10-24

    The interaction between graphene layers is analyzed combining local orbital DFT and second order perturbation theory. For this purpose we use the linear combination of atomic orbitals-orbital occupancy (LCAO-OO) formalism, that allows us to separate the interaction energy as the sum of a weak chemical interaction between graphene layers plus the van der Waals interaction (Dappe et al 2006 Phys. Rev. B 74 205434). In this work, the weak chemical interaction is calculated by means of corrected-LDA calculations using an atomic-like sp(3)d(5) basis set. The van der Waals interaction is calculated by means of second order perturbation theory using an atom-atom interaction approximation and the atomic-like-orbital occupancies. We also analyze the effect of dynamical screening in the van der Waals interaction using a simple model. We find that this dynamical screening reduces by 40% the van der Waals interaction. Taking this effect into account, we obtain a graphene-graphene interaction energy of 70 ± 5 meV/atom in reasonable agreement with the experimental evidence.

  1. Particle Energization in Earth's Van Allen Radiation Belts Due to Solar Wind Forcing

    NASA Astrophysics Data System (ADS)

    Baker, D. N.

    2017-12-01

    Early observations of the Earth's radiation environment clearly indicated that the Van Allen belts could be delineated into an inner zone dominated by high-energy protons and an outer zone dominated by high-energy electrons. The energy distribution, spatial extent and particle species makeup of the Van Allen belts has been subsequently explored by several space missions. However, recent observations by the NASA dual-spacecraft Van Allen Probes mission have revealed unexpected properties of the radiation belts, especially for electrons at highly relativistic (E > 2 MeV) and ultra-relativistic (E > 5 MeV) kinetic energies. In this presentation we show using high spatial and temporal resolution data from the experiments on board the Van Allen Probes that multiple belts can exist concurrently and that an exceedingly sharp inner boundary exists for ultra-relativistic electrons. Using additionally available Van Allen Probes data, we demonstrate that these remarkable features of energetic electrons are driven by strong solar and solar wind forcings. The comprehensive Van Allen Probes data show more broadly and in many ways how extremely high energy particles are accelerated, transported, and lost in the magnetosphere due to interplanetary shock wave interactions, coronal mass ejection impacts, and high-speed solar wind streams. The new data have shown especially how dayside processes play a key role in electron acceleration and loss processes.

  2. Martin Van Buren's "Return to the Soil." Teaching with Historic Places.

    ERIC Educational Resources Information Center

    National Register of Historic Places, Washington, DC. Interagency Resources Div.

    Using primary documents, maps, and visual data, this lesson packet focuses on Martin Van Buren and his retirement home, Lindenwald, which is on the National Register of Historic Places. The lesson materials compliment classroom study of early 19th century politics by tracing the life of Martin Van Buren and his role in the Jacksonian Era. Included…

  3. Relationship of the Van Herick Grading System with Peripheral Iris Configuration and Level of Iris Insertion.

    PubMed

    Khan, Faisal Aziz; Niazi, Shafaq Pervez Khan; Khan, Assad Zaman

    2017-09-01

    To determine the relationship of the van Herick angle grading system with the level of iris insertion and peripheral iris configuration. Observational study. Eye department, Combined Military Hospital, Malir Cantt., Karachi, from May to October 2015. Sixty-five eyes of 65 patients were recruited. Anterior chamber depth at the temporal limbus was measured as a fraction of corneal section thickness using van Herick technique and graded on the standard 4-point scale of the van Herick grading system. Gonioscopy of the temporal quadrant was performed with a Posner 4 mirror goniolens and both the true level of iris insertion and peripheral iris configuration were recorded on a 4-point scale so as to equate with the van Herick 4-point grading system. Spearman's rho test was applied to determine the relationship of the van Herick grading system with level of iris root insertion and peripheral iris configuration. Amoderate positive correlation between van Herick grade and peripheral iris configuration was found which was statistically significant (rs=0.42, p < 0.001). Astatistically significant and moderate positive correlation was also detected between van Herick grade and the level of iris insertion (rs=0.45, p < 0.001). The van Herick grade has a moderately positive relationship with the peripheral iris configuration and true level of iris insertion.

  4. NOAA's Van-Based Mobile Atmospheric Emissions Measurement Laboratory

    NASA Astrophysics Data System (ADS)

    Dube, W. P.; Peischl, J.; Neuman, J. A.; Eilerman, S. J.; Holloway, M.; Roberts, O.; Aikin, K. C.; Ryerson, T. B.

    2015-12-01

    The Chemical Science Division (CSD) mobile atmospheric emissions measurement laboratory is the second and latest of two mobile measurement vans outfitted for atmospheric sampling by the NOAA Earth System Research Laboratory. In this presentation we will describe the modifications made to this vehicle to provide a versatile and relatively inexpensive instrument platform including: the 2 kW 120 volt instrument power system; battery back-up system; data acquisition system; real-time display; meteorological, directional, and position sensor package; and the typical atmospheric emissions instrument package. The van conversion uses commercially available, off-the-shelf components from the marine and RV industries, thus keeping the costs quite modest.

  5. Dynamical property analysis of fractionally damped van der pol oscillator and its application

    NASA Astrophysics Data System (ADS)

    Zhong, Qiuhui; Zhang, Chunrui

    2012-01-01

    In this paper, the fractionally damped van der pol equation was studied. Firstly, the fractionally damped van der pol equation was transformed into a set of integer order equations. Then the Lyapunov exponents diagram was given. Secondly, it was transformed into a set of fractional integral equations and solved by a predictor-corrector method. The time domain diagrams and phase trajectory were used to describe the dynamic behavior. Finally, the fractionally damped van der pol equation was used to detect a weak signal.

  6. Accounting for apparent deviations between calorimetric and van't Hoff enthalpies.

    PubMed

    Kantonen, Samuel A; Henriksen, Niel M; Gilson, Michael K

    2018-03-01

    In theory, binding enthalpies directly obtained from calorimetry (such as ITC) and the temperature dependence of the binding free energy (van't Hoff method) should agree. However, previous studies have often found them to be discrepant. Experimental binding enthalpies (both calorimetric and van't Hoff) are obtained for two host-guest pairs using ITC, and the discrepancy between the two enthalpies is examined. Modeling of artificial ITC data is also used to examine how different sources of error propagate to both types of binding enthalpies. For the host-guest pairs examined here, good agreement, to within about 0.4kcal/mol, is obtained between the two enthalpies. Additionally, using artificial data, we find that different sources of error propagate to either enthalpy uniquely, with concentration error and heat error propagating primarily to calorimetric and van't Hoff enthalpies, respectively. With modern calorimeters, good agreement between van't Hoff and calorimetric enthalpies should be achievable, barring issues due to non-ideality or unanticipated measurement pathologies. Indeed, disagreement between the two can serve as a flag for error-prone datasets. A review of the underlying theory supports the expectation that these two quantities should be in agreement. We address and arguably resolve long-standing questions regarding the relationship between calorimetric and van't Hoff enthalpies. In addition, we show that comparison of these two quantities can be used as an internal consistency check of a calorimetry study. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. LEASAT-3 repair during the van Hoften and Fisher EVA

    NASA Image and Video Library

    1985-08-31

    51I-44-012 (1 Sept. 1985) --- Astronaut James D. van Hoften looks on as the Syncom IVC-3 satellite responds to his push against it moments earlier. Dr. van Hoften, mission specialist, is anchored to a foot restraint on the end of the remote manipulator system (RMS) arm of the Earth-orbiting space shuttle Discovery. The 51-I crew members showed this photograph at their Sept. 11 postflight press conference. Photo credit: NASA

  8. Analysis of crashes involving 15-passenger vans

    DOT National Transportation Integrated Search

    2004-05-01

    This study explores the relationship between vehicle occupancy and several other variables in the National Highway Traffic Safety Administration's (NHTSA's) Fatality Analysis Reporting System (FARS) database and a 15-passenger van's risk of rollover....

  9. A note on evaluating VAN earthquake predictions

    NASA Astrophysics Data System (ADS)

    Tselentis, G.-Akis; Melis, Nicos S.

    The evaluation of the success level of an earthquake prediction method should not be based on approaches that apply generalized strict statistical laws and avoid the specific nature of the earthquake phenomenon. Fault rupture processes cannot be compared to gambling processes. The outcome of the present note is that even an ideal earthquake prediction method is still shown to be a matter of a “chancy” association between precursors and earthquakes if we apply the same procedure proposed by Mulargia and Gasperini [1992] in evaluating VAN earthquake predictions. Each individual VAN prediction has to be evaluated separately, taking always into account the specific circumstances and information available. The success level of epicenter prediction should depend on the earthquake magnitude, and magnitude and time predictions may depend on earthquake clustering and the tectonic regime respectively.

  10. Critical lines for an unequal size of molecules in a binary gas-liquid mixture around the van Laar point using the combination of the Tompa model and the van der Waals equation.

    PubMed

    Gençaslan, Mustafa; Keskin, Mustafa

    2012-02-14

    We combine the modified Tompa model with the van der Waals equation to study critical lines for an unequal size of molecules in a binary gas-liquid mixture around the van Laar point. The van Laar point is coined by Meijer and it is the only point at which the mathematical double point curve is stable. It is the intersection of the tricritical point and the double critical end point. We calculate the critical lines as a function of χ(1) and χ(2), the density of type I molecules and the density of type II molecules for various values of the system parameters; hence the global phase diagrams are presented and discussed in the density-density plane. We also investigate the connectivity of critical lines at the van Laar point and its vicinity and discuss these connections according to the Scott and van Konynenburg classifications. It is also found that the critical lines and phase behavior are extremely sensitive to small modifications in the system parameters. © 2012 American Institute of Physics

  11. Van Vleck and the magnetic susceptibilities of gaseous molecules

    NASA Astrophysics Data System (ADS)

    Meyer, Horst

    2011-03-01

    In his 1927 Physical Review article and in his 1932 book, ~The Theory of Electric and Magnetic Susceptibilities,~Van Vleck used the new quantum theory to derive the magnetic susceptibilities of O2 and NO in their gaseous form ~and compared them with experiments. ~He was therefore very interested in low temperature susceptibility experiments on O2 at Oxford University in 1954 where individual O2 molecules were trapped in small, almost spherical cages in organic clathrates. Correspondence between him and this speaker, then at Oxford, led to further measurements of O2 and also of NO in such clathrates, to theory and to subsequent publications and correspondence. Later communication with Van Vleck on the magnetism in rare earth iron garnets, a subject of long-term interest to him, will be described ~in connection with experiments carried out at Duke University. Some fond personal ~recollections of this speaker of his interaction with Van Vleck - both while at Harvard, during visits and through correspondence which extended into the seventies - will be presented.

  12. Early Childhood Matters: The Bulletin of the Bernard van Leer Foundation, 1999.

    ERIC Educational Resources Information Center

    Smale, Jim, Ed.

    1999-01-01

    This document consists of the three 1999 issues of The Bernard van Leer Foundation's "Early Childhood Matters." This periodical, addressed to practitioners in the field of early childhood education, evolved from an in-house publication directed to projects funded by the Bernard van Leer Foundation. Articles in the February 1999 edition…

  13. Early Childhood Matters: The Bulletin of the Bernard van Leer Foundation, 1998.

    ERIC Educational Resources Information Center

    Smale, Jim, Ed.

    1998-01-01

    This document consists of the three 1998 issues of The Bernard van Leer Foundations'"Early Childhood Matters." This periodical, addressed to practitioners in the field of early childhood development, evolved from an in-house publication directed to projects funded by the Bernard van Leer Foundation. Articles in the February 1998 edition…

  14. Early Childhood Matters: The Bulletin of the Bernard van Leer Foundation, 2000.

    ERIC Educational Resources Information Center

    Smale, Jim, Ed.

    2000-01-01

    This document consists of the three 2000 issues of The Bernard van Leer Foundation's "Early Childhood Matters." This periodical, addressed to practitioners in the field of early childhood education, evolved from an in-house publication directed to projects funded by the Bernard van Leer Foundation. Articles in the February 2000 edition…

  15. 77 FR 44683 - Phillips-Van Heusen Corporation, IZOD Dress Furnishings Division, New York, NY; Notice of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-30

    ... for Reconsideration for the workers and former workers of Phillips-Van Heusen Corporation, IZOD Women... Phillips-Van Heusen Corporation, IZOD Women's Wholesale Division, New York, New York has not increased. In... Phillips-Van Heusen Corporation, IZOD Women's Wholesale Division, New York, New York) was incorrect, that...

  16. Atomically thin p-n junctions with van der Waals heterointerfaces.

    PubMed

    Lee, Chul-Ho; Lee, Gwan-Hyoung; van der Zande, Arend M; Chen, Wenchao; Li, Yilei; Han, Minyong; Cui, Xu; Arefe, Ghidewon; Nuckolls, Colin; Heinz, Tony F; Guo, Jing; Hone, James; Kim, Philip

    2014-09-01

    Semiconductor p-n junctions are essential building blocks for electronic and optoelectronic devices. In conventional p-n junctions, regions depleted of free charge carriers form on either side of the junction, generating built-in potentials associated with uncompensated dopant atoms. Carrier transport across the junction occurs by diffusion and drift processes influenced by the spatial extent of this depletion region. With the advent of atomically thin van der Waals materials and their heterostructures, it is now possible to realize a p-n junction at the ultimate thickness limit. Van der Waals junctions composed of p- and n-type semiconductors--each just one unit cell thick--are predicted to exhibit completely different charge transport characteristics than bulk heterojunctions. Here, we report the characterization of the electronic and optoelectronic properties of atomically thin p-n heterojunctions fabricated using van der Waals assembly of transition-metal dichalcogenides. We observe gate-tunable diode-like current rectification and a photovoltaic response across the p-n interface. We find that the tunnelling-assisted interlayer recombination of the majority carriers is responsible for the tunability of the electronic and optoelectronic processes. Sandwiching an atomic p-n junction between graphene layers enhances the collection of the photoexcited carriers. The atomically scaled van der Waals p-n heterostructures presented here constitute the ultimate functional unit for nanoscale electronic and optoelectronic devices.

  17. Phenotypic and genotypic characterization of vancomycin-resistant Enterococcus faecium clinical isolates from two hospitals in Mexico: First detection of VanB phenotype-vanA genotype.

    PubMed

    Bocanegra-Ibarias, Paola; Flores-Treviño, Samantha; Camacho-Ortiz, Adrián; Morfin-Otero, Rayo; Villarreal-Treviño, Licet; Llaca-Díaz, Jorge; Martínez-Landeros, Erik Alan; Rodríguez-Noriega, Eduardo; Calzada-Güereca, Andrés; Maldonado-Garza, Héctor Jesús; Garza-González, Elvira

    2016-01-01

    Enterococcus faecium has emerged as a multidrug-resistant nosocomial pathogen involved in outbreaks worldwide. Our aim was to determine the antimicrobial susceptibility, biofilm production, and clonal relatedness of vancomycin-resistant E. faecium (VREF) clinical isolates from two hospitals in Mexico. Consecutive clinical isolates (n=56) were collected in two tertiary care hospitals in Mexico from 2011 to 2014. VREF isolates were characterized by phenotypic and molecular methods including pulsed-field gel electrophoresis (PFGE). VREF isolates were highly resistant to vancomycin, erythromycin, norfloxacin, high-level streptomycin, and teicoplanin, and showed lower resistance to tetracycline, nitrofurantoin and quinupristin-dalfopristin. None of the isolates were resistant to linezolid. The vanA gene was detected in all isolates. Two VanB phenotype-vanA genotype isolates, highly resistant to vancomycin and susceptible to teicoplanin, were detected. Furthermore, 17.9% of the isolates were classified as biofilm producers, and the espfm gene was found in 98.2% of the isolates. A total of 37 distinct PFGE patterns and 6 clones (25% of the isolates as clone A, 5.4% as clone B, and 3.6% each as clone C, D, E, and F) were detected. Clone A was detected in 5 different wards of the same hospital during 14 months of surveillance. The high resistance to most antimicrobial agents and the moderate cross-transmission of VREF detected accentuates the need for continuous surveillance of E. faecium in the hospital setting. This is also the first reported incidence of the E. faecium VanB phenotype-vanA genotype in the Americas. Copyright © 2015 Elsevier España, S.L.U. and Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

  18. Bernard van Leer Foundation Newsletter, 1996.

    ERIC Educational Resources Information Center

    Bernard van Leer Foundation, Newsletter, 1996

    1996-01-01

    This document consists of the four issues of the Bernard van Leer Foundation's "Newsletter" published during 1996. The newsletter covers topics related to, or about efforts to foster, the education and welfare of children around the world, and includes descriptions of programs around the world, lists of resources and publications, and…

  19. Transcriptional Analysis of the vanC Cluster from Enterococcus gallinarum Strains with Constitutive and Inducible Vancomycin Resistance

    PubMed Central

    Panesso, Diana; Abadía-Patiño, Lorena; Vanegas, Natasha; Reynolds, Peter E.; Courvalin, Patrice; Arias, Cesar A.

    2005-01-01

    The vanC glycopeptide resistance gene cluster encodes enzymes required for synthesis of peptidoglycan precursors ending in d-Ala-d-Ser. Enterococcus gallinarum BM4174 and SC1 are constitutively and inducibly resistant to vancomycin, respectively. Analysis of peptidoglycan precursors in both strains indicated that UDP-MurNAc-tetrapeptide and UDP-MurNAc-pentapeptide[d-Ser] were synthesized in E. gallinarum SC1 only in the presence of vancomycin (4 μg/ml), whereas the “resistance” precursors accumulated in the cytoplasm of BM4174 cells under both inducing and noninducing conditions. Northern hybridization and reverse transcription-PCR experiments revealed that all the genes from the cluster, vanC-1, vanXYC, vanT, vanRC, and vanSC, were transcribed from a single promoter. In the inducible SC1 isolate, transcriptional regulation appeared to be responsible for inducible expression of resistance. Promoter mapping in E. gallinarum BM4174 revealed that the transcriptional start site was located 30 nucleotides upstream from vanC-1 and that the −10 promoter consensus sequence had high identity with that of the vanA cluster. Comparison of the deduced sequence of the vanSC genes from isolates with constitutive and inducible resistance revealed several amino acid substitutions located in the X box (R200L) and in the region between the F and G2 boxes (D312N, D312A, and G320S) of the putative sensor kinase proteins from isolates with constitutive resistance. PMID:15728903

  20. Baseline tests of the Volkswagen transporter electric delivery van

    NASA Technical Reports Server (NTRS)

    Soltis, R. F.; Mcbrien, E. F.; Bozek, J. M.; Gourash, F.

    1978-01-01

    The Volkswagen Transporter, an electric delivery van, was tested as part of an Energy Research and Development Administration (ERDA) project to characterize the state of the art of electric vehicles. The Volkswagen Transporter is a standard Volkswagen van that has been converted to an electric vehicle. It is powered by a 144-volt traction battery. A direct current (dc) chopper controller, actuated by a conventional accelerator pedal, regulates the voltage or power applied to the 16-kilowatt (21-hp) motor. The braking system uses conventional hydraulic braking in combination with an electric regenerative braking system. The Volkswagen vehicle performance test results are presented.

  1. Onderzoek Naar de Bepaling van Wrijvingscoefficienten van een Voertuig uit Uitrolcurves (Research into the Determination of Friction Coefficients of a Vehicle from Deceleration Curves)

    DTIC Science & Technology

    1991-08-01

    en Aemne Vrwaarden Wo OndOrzoeks 8 FE 1 1 opdrchl aT00’ dn wet do bereflende F B 0 1 9 terzake tussen partilon geslOlen dw:Agsu overOerikomStf...Ongemlbric~~d 9 -028 14 :259 wwWmtmd.fl 59w IEEIIIIiiiarabIg𔃽 1 c~ Vrederikkazerle, Geb. InO 03 3.. ~ van den Burchlaal 312 03 173Telefoofl 070-3166394...1ILEIDING 6 2 HET FYSISCHE MODEL 8 3 ONDERZOEK AAN DE DIFFERENTIAALVERGELIJKING 11 3.1 Existentie en uniciteit van ccii oplossing 11 3.2 Continulleit en

  2. The van Gogh of the Infrared Sky

    NASA Image and Video Library

    2011-04-25

    NASA Wide-field Infrared Survey Explorer is a little like the Vincent van Gogh of the infrared sky, providing the world with picturesque images of the cosmos by representing infrared light through color. This image is the nebula NGC 2174.

  3. Eisen voor Buitenbeelden van Voertuigsimulatoren: Een Literatuurstudie (Use of Exterior Pictures in Vehicle Simulators: A Literature Survey)

    DTIC Science & Technology

    1991-06-01

    1.3 Opleiding en onderzoek met voertuigsimulatoren 9 1.4 Opbouw van simulatoren 11 1.5 Totstandkomning van beelden in CGI-systemen 13 1.6 Bepalen van...pictures in vehicle simulators. A literature survey s 029 9 20 Aantal bladzijden: 102 .JISTRIBIYI±WN- STATEMEN9 -2 39 Approved for public release; 2 28 9 ...Achteruitkijkspiegels en verrekijkers 79 8.2 Helderheidsversterkers en warmtebeelden 80 8.3 Middelen om afstand te bepalen 80 9 INTERACTIES VAN HET

  4. Van, Turkey Earthquake of 23 October 2011, Mw 7.2; An Overview on Disaster Management

    PubMed Central

    ZARÉ, Mehdi; NAZMAZAR, Behnaz

    2013-01-01

    An earthquake was happened on 23 October 2011 in Van, Turkey (Mw7.2) at the eastern most area of Anatolian plateau and in the neighborhood of Iranian border (West Azerbaijan Province). The study was performed based on field and office observations and has been focused on the process of disaster management in Turkey after the 23 October 2011 earthquake. We surveyed the quake from the view point of disaster management, and study the relief process during and after the catastrophe. The day-to-day disaster management procedure in seventeen days after the event has been scrutinized as well. The number of victims and extent of damage in Van earthquake was relatively limited according to the national experiences and recent modernization of infrastructures in Turkey. The Van earthquake caused 644 deaths and demolishing of several buildings in the cities of Van and Erciş in Van Province. The performance of the government organizations is however criticized based on their response to the event. PMID:23515082

  5. Resonance oscillations of nonreciprocal long-range van der Waals forces between atoms in electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Sherkunov, Yury

    2018-03-01

    We study theoretically the van der Waals interaction between two atoms out of equilibrium with an isotropic electromagnetic field. We demonstrate that at large interatomic separations, the van der Waals forces are resonant, spatially oscillating, and nonreciprocal due to resonance absorption and emission of virtual photons. We suggest that the van der Waals forces can be controlled and manipulated by tuning the spectrum of artificially created random light.

  6. Q & A with Carmella Van Vleet

    ERIC Educational Resources Information Center

    Curriculum Review, 2008

    2008-01-01

    This article presents an interview with Carmella Van Vleet, a former teacher and educational speaker. She has written family humor and parenting articles, and is also the author of "How to Handle School Snafus," "Great Ancient Egypt Projects You Can Build Yourself" and "Amazing Ben Franklin Inventions You Can Build Yourself." In this interview,…

  7. Investigating the Effect of van Hiele Phase-Based Instruction on Pre-Service Teachers' Geometric Thinking

    ERIC Educational Resources Information Center

    Armah, Robert Benjamin; Cofie, Primrose Otokonor; Okpoti, Christopher Adjei

    2018-01-01

    This study investigated the effect of van Hiele Phase-based Instruction (VHPI) on Ghanaian Pre-service Teachers' (PTs') geometric thinking in terms of the van Hiele Levels. A pre-test post-test quasi-experimental design was employed. There were 75 PTs each in the experimental group and the control group. Van Hiele Geometry Test (VHGT) was…

  8. Evidence of van Hove singularities in ordered grain boundaries of graphene.

    PubMed

    Ma, Chuanxu; Sun, Haifeng; Zhao, Yeliang; Li, Bin; Li, Qunxiang; Zhao, Aidi; Wang, Xiaoping; Luo, Yi; Yang, Jinlong; Wang, Bing; Hou, J G

    2014-06-06

    It has long been under debate whether the electron transport performance of graphene could be enhanced by the possible occurrence of van Hove singularities in grain boundaries. Here, we provide direct experimental evidence to confirm the existence of van Hove singularity states close to the Fermi energy in certain ordered grain boundaries using scanning tunneling microscopy. The intrinsic atomic and electronic structures of two ordered grain boundaries, one with alternative pentagon and heptagon rings and the other with alternative pentagon pair and octagon rings, are determined. It is firmly verified that the carrier concentration and, thus, the conductance around ordered grain boundaries can be significantly enhanced by the van Hove singularity states. This finding strongly suggests that a graphene nanoribbon with a properly embedded ordered grain boundary can be a promising structure to improve the performance of graphene-based electronic devices.

  9. Concurrent Van der Woude syndrome and Turner syndrome: A case report.

    PubMed

    Los, Evan; Baines, Hayley; Guttmann-Bauman, Ines

    2017-01-01

    Most cases of Van der Woude syndrome are caused by a mutation to interferon regulatory factor 6 on chromosome 1. Turner syndrome is caused by complete or partial absence of the second sex chromosome in girls. We describe a unique case of the two syndromes occurring concurrently though apparently independently in a girl with Van der Woude syndrome diagnosed at birth and Turner syndrome at 14 years 9 months. Short stature was initially misattributed to Van der Woude syndrome and pituitary insufficiency associated with clefts before correctly diagnosing Turner syndrome. We discuss the prevalence of delayed diagnosis of Turner syndrome, the rarity of reports of concurrent autosomal chromosome mutation and sex chromosome deletion, as well as the need to consider the diagnosis of Turner syndrome in all girls with short stature regardless of prior medical history.

  10. [Issenheim's altarpiece: does the disease depicted on the altarpiece correspond to ergotism?].

    PubMed

    Faure, Michel

    2010-01-01

    The Issenheim altar by Mathias Grünenwald (Unterlinden museum in Colmar) shows various scenes from the life of St Antony, abbot. The Tentation panel has been considered as an illustration of the sacer ignis, or St Antony's disease (ergotism). In fact, it may more likely indicate an early representation of Syphilis, or the French disease, as discussed here.

  11. Geologic environment of the Van Norman Reservoirs area

    USGS Publications Warehouse

    Yerkes, R.F.; Bonilla, M.G.; Youd, T.L.; Sims, J.D.

    1974-01-01

    The upper and lower Van Norman dams, in northwesternmost San Fernando Valley about 20 mi (32 km) northwest of downtown Los Angeles, were severely damaged during the 1971 San Fernando earthquake. An investigation of the geologic-seismologic setting of the Van Norman area indicates that an earthquake of at least M 7.7 may be expected in the Van Norman area. The expectable transitory effects in the Van Norman area of such an earthquake are as follows: peak horizontal acceleration of at least 1.15 g, peak velocity of displacement of 4.43 ft/sec (135 cm/sec), peak displacement of 2.3 ft (70 cm), and duration of shaking at accelerations greater than 0.05 g, 40 sec. A great earthquake (M 8+) on the San Andreas fault, 25 mi distant, also is expectable. Transitory effects in the Van Norman area from such an earthquake are estimated as follows: peak horizontal acceleration of 0.5 g, peak velocity of 1.97 ft/sec (60 cm/sec), displacement of 1.31 ft (40 cm), and duration of shaking at accelerations greater than 0.05 g, 80 sec. The permanent effects of the expectable local earthquake could include simultaneous fault movement at the lower damsite, the upper damsite, and the site proposed for a replacement dam halfway between the upper and lower dams. The maximum differential displacements due to such movements are estimated at 16.4 ft (5 m) at the lower damsite and about 9.6 ft (2.93 m) at the upper and proposed damsites. The 1971 San Fernando earthquake (M 6?) was accompanied by the most intense ground motions ever recorded instrumentally for a natural earthquake. At the lower Van Norman dam, horizontal accelerations exceeded 0.6 g, and shaking greater than 0.25 g lasted for about 13 see; at Pacoima dam, 6 mi (10 km) northeast of the lower dam, high-frequency peak horizontal accelerations of 1.25 g were recorded in two directions, and shaking greater than 0.25 g lasted for about 7 sec. Permanent effects of the earthquake include slope failures in the embankments of the upper

  12. Van Allen Probes Science Gateway: A Centralized Data Access Point

    NASA Astrophysics Data System (ADS)

    Romeo, G.; Barnes, R. J.; Ukhorskiy, A. Y.; Sotirelis, T.; Stephens, G. K.; Kessel, R.; Potter, M.

    2015-12-01

    The Van Allen Probes Science Gateway acts a centralized interface to the instrument Science Operation Centers (SOCs), provides mission planning tools, and hosts a number of science related activities such as the mission bibliography. Most importantly, the Gateway acts as the primary site for processing and delivering the Van Allen Probes Space Weather data to users. Over the past years, the web-site has been completely redesigned with the focus on easier navigation and improvements of the existing tools such as the orbit plotter, position calculator and magnetic footprint tool. In addition, a new data plotting facility has been added. Based on HTML5, which allows users to interactively plot Van Allen Probes science and space weather data. The user can tailor the tool to display exactly the plot they wish to see and then share this with other users via either a URL or by QR code. Various types of plots can be created, including, simple time series, data plotted as a function of orbital location, and time versus L-Shell, capability of visualizing data from both probes (A & B) on the same plot. In cooperation with all Van Allen Probes Instrument SOCs, the Science Gateway will soon be able to serve higher level data products (Level 3), and to visualize them via the above mentioned HTML5 interface. Users will also be able to create customized CDF files on the fly.

  13. Presence of the resistance genes vanC1 and pbp5 in phenotypically vancomycin and ampicillin susceptible Enterococcus faecalis.

    PubMed

    Schwaiger, Karin; Bauer, Johann; Hörmansdorfer, Stefan; Mölle, Gabriele; Preikschat, Petra; Kämpf, Peter; Bauer-Unkauf, Ilse; Bischoff, Meike; Hölzel, Christina

    2012-08-01

    Ampicillin and vancomycin are important antibiotics for the therapy of Enterococcus faecalis infections. The ampicillin resistance gene pbp5 is intrinsic in Enterococcus faecium. The vanC1 gene confers resistance to vancomycin and serves as a species marker for Enterococcus gallinarum. Both genes are chromosomally located. Resistance to ampicillin and vancomycin was determined in 484 E. faecalis of human and porcine origin by microdilution. Since E. faecalis are highly skilled to acquire resistance genes, all strains were investigated for the presence of pbp5 (and, in positive strains, for the penicillin-binding protein synthesis repressor gene psr) and vanC1 (and, in positive strains, for vanXYc and vanT) by using polymerase chain reaction (PCR). One porcine and one human isolate were phenotypically resistant to ampicillin; no strain was vancomycin resistant. Four E. faecalis (3/1 of porcine/human origin) carried pbp5 (MIC=1 mg/L), and four porcine strains were vanC1 positive (minimum inhibitory concentration [MIC]=1 mg/L). Real-time reverse transcriptase (RT)-PCR revealed that the genes were not expressed. The psr gene was absent in the four pbp5-positive strains; the vanXYc gene was absent in the four vanC1-positive strains. However, vanT of the vanC gene cluster was detected in two vanC1-positive strains. To our knowledge, this is the first report on the presence of pbp5, identical with the "E. faecium pbp5 gene," and of vanC1/vanT in E. faecalis. Even if resistance is not expressed in these strains, this study shows that E. faecalis have a strong ability to acquire resistance genes-and potentially to spread them to other bacteria. Therefore, close monitoring of this species should be continued.

  14. Simon van der Meer (1925-2011):. A Modest Genius of Accelerator Science

    NASA Astrophysics Data System (ADS)

    Chohan, Vinod C.

    2011-02-01

    Simon van der Meer was a brilliant scientist and a true giant of accelerator science. His seminal contributions to accelerator science have been essential to this day in our quest for satisfying the demands of modern particle physics. Whether we talk of long base-line neutrino physics or antiproton-proton physics at Fermilab or proton-proton physics at LHC, his techniques and inventions have been a vital part of the modern day successes. Simon van der Meer and Carlo Rubbia were the first CERN scientists to become Nobel laureates in Physics, in 1984. Van der Meer's lesserknown contributions spanned a whole range of subjects in accelerator science, from magnet design to power supply design, beam measurements, slow beam extraction, sophisticated programs and controls.

  15. The integrable case of Adler-van Moerbeke. Discriminant set and bifurcation diagram

    NASA Astrophysics Data System (ADS)

    Ryabov, Pavel E.; Oshemkov, Andrej A.; Sokolov, Sergei V.

    2016-09-01

    The Adler-van Moerbeke integrable case of the Euler equations on the Lie algebra so(4) is investigated. For the L- A pair found by Reyman and Semenov-Tian-Shansky for this system, we explicitly present a spectral curve and construct the corresponding discriminant set. The singularities of the Adler-van Moerbeke integrable case and its bifurcation diagram are discussed. We explicitly describe singular points of rank 0, determine their types, and show that the momentum mapping takes them to self-intersection points of the real part of the discriminant set. In particular, the described structure of singularities of the Adler-van Moerbeke integrable case shows that it is topologically different from the other known integrable cases on so(4).

  16. Identification of VanN-type vancomycin resistance in an Enterococcus faecium isolate from chicken meat in Japan.

    PubMed

    Nomura, Takahiro; Tanimoto, Koichi; Shibayama, Keigo; Arakawa, Yoshichika; Fujimoto, Shuhei; Ike, Yasuyoshi; Tomita, Haruyoshi

    2012-12-01

    Five VanN-type vancomycin-resistant Enterococcus faecium strains were isolated from a sample of domestic chicken meat in Japan. All isolates showed low-level resistance to vancomycin (MIC, 12 mg/liter) and had the same pulsed-field gel electrophoresis profile. The vancomycin resistance was encoded on a large plasmid (160 kbp) and was expressed constitutively. The VanN-type resistance operon was identical to the first resistance operon to be reported, with the exception of a 1-bp deletion in vanT(N) and a 1-bp substitution in vanS(N).

  17. Mid infrared observations of Van Maanen 2: no substellar companion.

    SciTech Connect

    Farihi, J; Becklin, E; Macintosh, B

    2004-11-03

    The results of a comprehensive infrared imaging search for the putative 0.06 M{sub {circle_dot}} astrometric companion to the 4.4 pc white dwarf van Mannen 2 are reported. Adaptive optics images acquired at 3.8 {micro}m reveal a diffraction limited core of 0.09 inch and no direct evidence of a secondary. Models predict that at 5 Gyr, a 50 M{sub J} brown dwarf would be only 1 magnitude fainter than van Maanen 2 at this wavelength and the astrometric analysis suggested a separation of 0.2 inch. In the case of a chance alignment along the line of sight, a 0.4 mag excessmore » should be measured. An independent photometric observation at the same wavelength reveals no excess. In addition, there exist published ISO observations of van Maanen 2 at 6.8 {micro}m and 15.0 {micro}m which are consistent with photospheric flux of a 6750 K white dwarf. If recent brown dwarf models are correct, there is no substellar companion with T{sub eff} {approx}> 500 K.« less

  18. The Forced van der Pol Equation

    ERIC Educational Resources Information Center

    Fay, Temple H.

    2009-01-01

    We report on a study of the forced van der Pol equation x + [epsilon](x[superscript 2] - 1)x + x = F cos[omega]t, by solving numerically the differential equation for a variety of values of the parameters [epsilon], F and [omega]. In doing so, many striking and interesting trajectories can be discovered and phenomena such as frequency entrainment,…

  19. Willem van de Wall: Organizer and Innovator in Music Education and Music Therapy.

    ERIC Educational Resources Information Center

    Clair, Alicia Ann; Heller, George N.

    1989-01-01

    Examines Willem van de Wall's historically significant contributions to seminal literature on music therapy and the influence of music on behavior. Reviews van de Wall's early writings, at his work on music for children, and on music in institutions. Cites his "Music in Hospitals" as the culmination of his work in music therapy, music…

  20. [Mobile hospital -real time mobile telehealthcare system with ultrasound and CT van using high-speed satellite communication-].

    PubMed

    Takizawa, Masaomi; Miyashita, Toyohisa; Murase, Sumio; Kanda, Hirohito; Karaki, Yoshiaki; Yagi, Kazuo; Ohue, Toru

    2003-01-01

    A real-time telescreening system is developed to detect early diseases for rural area residents using two types of mobile vans with a portable satellite station. The system consists of a satellite communication system with 1.5Mbps of the JCSAT-1B satellite, a spiral CT van, an ultrasound imaging van with two video conference system, a DICOM server and a multicast communication unit. The video image and examination image data are transmitted from the van to hospitals and the university simultaneously. Physician in the hospital observes and interprets exam images from the van and watches the video images of the position of ultrasound transducer on screenee in the van. After the observation images, physician explains a results of the examination by the video conference system. Seventy lung CT screening and 203 ultrasound screening were done from March to June 2002. The trial of this real time screening suggested that rural residents are given better healthcare without visit to the hospital. And it will open the gateway to reduce the medical cost and medical divide between city area and rural area.

  1. Design of a command, communications, and control van (surrogate)

    NASA Astrophysics Data System (ADS)

    Holder, J. Darryl; Fishback, Jerome

    1989-03-01

    This report describes the design, construction, and checkout of a radio and telephone multi-mode communications hub. This unit is to serve as a surrogate for a command, control, and communications van which is to be used in support of a special series of testing at a remote site. This unit is assembled in a military four-wheel van and has a crew of a commander and three operators. Radio communications monitoring can be performed in all popular modes of transmission from 50 KHz to 2 GHz and transmission can be performed on selected frequencies in the 40-meter, 6-meter, and 2-meter bands. Both voice and digital (teletype, packet, facsimile, etc.) communications are supported.

  2. Testing the dynamic rollover resistance of two 15-passenger vans with multiple load configurations

    DOT National Transportation Integrated Search

    2004-06-01

    As a consequence of NTSB Safety Recommendations H-02-26 and H-02-28, NHTSA performed a study to investigate the effects different load conditions may have on the dynamic rollover resistance of 15-passenger vans. The two vans used in this study, a 200...

  3. A New Method for Suppressing Periodic Narrowband Interference Based on the Chaotic van der Pol Oscillator

    NASA Astrophysics Data System (ADS)

    Lu, Jia; Zhang, Xiaoxing; Xiong, Hao

    The chaotic van der Pol oscillator is a powerful tool for detecting defects in electric systems by using online partial discharge (PD) monitoring. This paper focuses on realizing weak PD signal detection in the strong periodic narrowband interference by using high sensitivity to the periodic narrowband interference signals and immunity to white noise and PD signals of chaotic systems. A new approach to removing the periodic narrowband interference by using a van der Pol chaotic oscillator is described by analyzing the motion characteristic of the chaotic oscillator on the basis of the van der Pol equation. Furthermore, the Floquet index for measuring the amplitude of periodic narrowband signals is redefined. The denoising signal processed by the chaotic van der Pol oscillators is further processed by wavelet analysis. Finally, the denoising results verify that the periodic narrowband and white noise interference can be removed efficiently by combining the theory of the chaotic van der Pol oscillator and wavelet analysis.

  4. Bernard van Leer Foundation Annual Report, 2001.

    ERIC Educational Resources Information Center

    Bernard Van Leer Foundation, The Hague (Netherlands).

    This annual report for 2001 describes the year's activities, achievements, and financial status of the Bernard van Leer Foundation, a private foundation based in The Netherlands operating internationally to improve opportunities for young children from birth to age 7 living in circumstances of social and economic disadvantage. Following the…

  5. Bernard van Leer Foundation Annual Report, 2002.

    ERIC Educational Resources Information Center

    Bernard Van Leer Foundation, The Hague (Netherlands).

    This annual report for 2002 describes the year's activities, achievements, and financial status of the Bernard van Leer Foundation, a private foundation based in The Netherlands operating internationally to improve opportunities for young children from birth to age 7 living in circumstances of social and economic disadvantage. Following the…

  6. Recent Science Highlights of the Van Allen Probes Mission

    NASA Astrophysics Data System (ADS)

    Ukhorskiy, Aleksandr

    2016-10-01

    The morning of 30 August 2012 saw an Atlas 5 rocket launch NASA's second Living With a Star spacecraft mission, the twin Radiation Belt Storm Probes, into an elliptic orbit cutting through Earth's radiation belts. Renamed the Van Allen Probes soon after launch, the Probes are designed to determine how the highly variable populations of high-energy charged particles within the radiation belts, dangerous to astronauts and satellites, are created, respond to solar variations, and evolve in space environments. The Van Allen Probes mission extends beyond the practical considerations of the hazard's of Earth's space environment. Twentieth century observations of space and astrophysical systems throughout the solar system and out into the observable universe have shown that the processes that generate intense particle radiation within magnetized environments such as Earth's are universal. During its mission the Van Allen Probes verified and quantified previously suggested energization processes, discovered new energization mechanisms, revealed the critical importance of dynamic plasma injections into the innermost magnetosphere, and used uniquely capable instruments to reveal inner radiation belt features that were all but invisible to previous sensors. This paper gives a brief overview of the mission, presents some recent science highlights, and discusses plans for the extended mission.

  7. Research and the Bernard van Leer Foundation.

    ERIC Educational Resources Information Center

    Wall, W. D.

    1978-01-01

    Outlines Bernard van Leer Foundation sponsorship of action programs and research studies of child development in 25 countries. The problems and possibilities of such work are discussed from the viewpoint of evaluation and the contribution which can be made to the behavioral sciences--notably to comparative child development. (Author/RH)

  8. Bernard van Leer Foundation Annual Report, 1999.

    ERIC Educational Resources Information Center

    Bernard Van Leer Foundation, The Hague (Netherlands).

    This annual report details the activities and financial status for 1999 of the Bernard van Leer Foundation, a private institution created in 1949 for broad humanitarian purposes. Following the introduction by the chairman of the Foundation's board of trustees, the report of the executive director details activities during the Foundation's fiftieth…

  9. Bernard van Leer Foundation Annual Report, 2000.

    ERIC Educational Resources Information Center

    Bernard Van Leer Foundation, The Hague (Netherlands).

    This annual report for 2000 describes the year's activities, achievements, and financial status of the Bernard van Leer Foundation, a private foundation based in The Netherlands that operates internationally to improve opportunities for young children from birth to age 7 living in circumstances of social and economic disadvantage. Following an…

  10. Overview of the critical disaster management challenges faced during Van 2011 earthquakes.

    PubMed

    Tolon, Mert; Yazgan, Ufuk; Ural, Derin N; Goss, Kay C

    2014-01-01

    On October 23, 2011, a M7.2 earthquake caused damage in a widespread area in the Van province located in eastern Turkey. This strong earthquake was followed by a M5.7 earthquake on November 9, 2011. This sequence of damaging earthquakes led to 644 fatalities. The management during and after these earthquake disaster imposed many critical challenges. In this article, an overview of these challenges is presented based on the observations by the authors in the aftermath of this disaster. This article presents the characteristics of 2011 Van earthquakes. Afterward, the key information related to the four main phases (ie, preparedness, mitigation, response, and recovery) of the disaster in Van is presented. The potential strategies that can be taken to improve the disaster management practice are identified, and a set of recommendations are proposed to improve the existing situation.

  11. Conversion of Chemical Reaction Energy into Useful Work in the Van't Hoff Equilibrium Box

    ERIC Educational Resources Information Center

    Bazhin, N. M.; Parmon, V. N.

    2007-01-01

    The ideal van't Hoff equilibrium box is described in detail. It shows that van't Hoff equilibrium box divided in two parts can simultaneously produce heat and useful work without violation of the first law of thermodynamics.

  12. Heath Van Essen - Clean Water Act Public Notice

    EPA Pesticide Factsheets

    The EPA is providing notice of a proposed Administrative Penalty Assessment against Heath Van Essen, Respondent, an individual who owns or operates an animal feeding operation (“Facility”) that is located in Section 27 of Township 98 North, Range 47 West,

  13. Confirming the appearance of excess success: Reply to van Boxtel and Koch (2016).

    PubMed

    Francis, Gregory

    2016-12-01

    van Boxtel and Koch (Psychonomic Bulletin & Review. doi: 10.3758/s13423-016-1010-0 , 2016) reported finding problems in the Test for Excess Success (TES) analysis in Francis (Psychonomic Bulletin & Review, 21, 1180-1187, 2014). They argued that their findings undermined the general analysis and the conclusions of the specific TES analysis for their article (van Boxtel & Koch in Psychological Science, 23(4), 410-418, 2012). As shown in this paper, their reported problems reflect misunderstandings about both the general properties of a TES analysis and how it was applied to their specific set of findings. Another look at the findings and theoretical claims in van Boxtel and Koch (Psychological Science, 23(4), 410-418, 2012) confirms the appearance of excess success.

  14. Comparison of three PCR primer sets for identification of vanB gene carriage in feces and correlation with carriage of vancomycin-resistant enterococci: interference by vanB-containing anaerobic bacilli.

    PubMed

    Ballard, S A; Grabsch, E A; Johnson, P D R; Grayson, M L

    2005-01-01

    We assessed the sensitivities and specificities of three previously described PCR primers on enrichment broth cultures of feces for the accurate detection of fecal carriage of vancomycin-resistant enterococci (VRE). In addition, we investigated specimens that were vanB PCR positive but VRE culture negative for the presence of other vanB-containing pathogens. Feces from 59 patients (12 patients carrying vanB Enterococcus faecium strains and 47 patients negative for VRE carriage) were cultured for 36 h in aerobic brain heart infusion (BHI) broth, anaerobic BHI (AnO(2)BHI) broth, or aerobic Enterococcosel (EC) broth. DNA was extracted from the cultures and tested for the presence of vanB by using the PCR primers of Dutka-Malen et al. (S. Dutka-Malen, S. Evers, and P. Courvalin, J. Clin. Microbiol. 33:24-27, 1995), Bell et al. (J. M. Bell, J. C. Paton, and J. Turnidge, J. Clin. Microbiol. 36:2187-2190, 1998), and Stinear et al. (T. P. Stinear, D. C. Olden, P. D. R. Johnson, J. K. Davies, and M. L. Grayson, Lancet 357:855-856, 2001). The sensitivity (specificity) of PCR compared with the results of culture on BHI, AnO(2)BHI, and EC broths were 67% (96%), 50% (94%), and 17% (100%), respectively, with the primers of Dutka-Malen et al.; 92% (60%), 92% (45%), and 92% (83%), respectively, with the primers of Bell et al.; and 92% (49%), 92% (43%), and 100% (51%) respectively, with the primers of Stinear et al. The primers of both Bell et al. and Stinear et al. were significantly more sensitive than those of Dutka-Malen et al. in EC broth (P = 0.001 and P < 0.001, respectively). The poor specificities for all primer pairs were due in part to the isolation and identification of six anaerobic gram-positive bacilli, Clostridium hathewayi (n = 3), a Clostridium innocuum-like organism (n = 1), Clostridium bolteae (n = 1), and Ruminococcus lactaris-like (n = 1), from five fecal specimens that were vanB positive but VRE culture negative. All six organisms were demonstrated to contain

  15. Bernard van Leer Foundation Annual Report 1998.

    ERIC Educational Resources Information Center

    Bernard Van Leer Foundation, The Hague (Netherlands).

    This document provides an annual report and financial review for 1998 of the Bernard van Leer Foundation, a private institution created in 1949 for broad humanitarian purposes. Following an introduction by chairman of the Foundation's board of trustees, a report of the executive director details the second year of implementation of the…

  16. Van der Waals forces in pNRQED

    SciTech Connect

    Shtabovenko, Vladyslav

    2016-01-22

    We report on the calculation of electromagnetic van der Waals forces [1] between two hydrogen atoms using non-relativistic effective field theories (EFTs) of QED for large and small momentum transfers with respect to the intrinsic energy scale of the hydrogen atom. Our results reproduce the well known London and Casimir-Polder forces.

  17. Dynamical importance of van der Waals saddle and excited potential surface in C(1D)+D2 complex-forming reaction

    PubMed Central

    Shen, Zhitao; Ma, Haitao; Zhang, Chunfang; Fu, Mingkai; Wu, Yanan; Bian, Wensheng; Cao, Jianwei

    2017-01-01

    Encouraged by recent advances in revealing significant effects of van der Waals wells on reaction dynamics, many people assume that van der Waals wells are inevitable in chemical reactions. Here we find that the weak long-range forces cause van der Waals saddles in the prototypical C(1D)+D2 complex-forming reaction that have very different dynamical effects from van der Waals wells at low collision energies. Accurate quantum dynamics calculations on our highly accurate ab initio potential energy surfaces with van der Waals saddles yield cross-sections in close agreement with crossed-beam experiments, whereas the same calculations on an earlier surface with van der Waals wells produce much smaller cross-sections at low energies. Further trajectory calculations reveal that the van der Waals saddle leads to a torsion then sideways insertion reaction mechanism, whereas the well suppresses reactivity. Quantum diffraction oscillations and sharp resonances are also predicted based on our ground- and excited-state potential energy surfaces. PMID:28094253

  18. Van Allen Probes Science Gateway and Space Weather Data Processing

    NASA Astrophysics Data System (ADS)

    Romeo, G.; Barnes, R. J.; Weiss, M.; Fox, N. J.; Mauk, B.; Potter, M.; Kessel, R.

    2014-12-01

    The Van Allen Probes Science Gateway acts as a centralized interface to the instrument Science Operation Centers (SOCs), provides mission planning tools, and hosts a number of science related activities such as the mission bibliography. Most importantly, the Gateway acts as the primary site for processing and delivering the VAP Space Weather data to users. Over the past year, the web-site has been completely redesigned with the focus on easier navigation and improvements of the existing tools such as the orbit plotter, position calculator and magnetic footprint tool. In addition, a new data plotting facility has been added. Based on HTML5, which allows users to interactively plot Van Allen Probes summary and space weather data. The user can tailor the tool to display exactly the plot they wish to see and then share this with other users via either a URL or by QR code. Various types of plots can be created, including simple time series, data plotted as a function of orbital location, and time versus L-Shell. We discuss the new Van Allen Probes Science Gateway and the Space Weather Data Pipeline.

  19. Determining Core Plasmaspheric Electron Densities with the Van Allen Probes

    NASA Astrophysics Data System (ADS)

    De Pascuale, S.; Hartley, D.; Kurth, W. S.; Kletzing, C.; Thaller, S. A.; Wygant, J. R.

    2016-12-01

    We survey three methods for obtaining electron densities inside of the core plasmasphere region (L < 4) to the perigee of the Van Allen Probes (L 1.1) from September 2012 to December 2014. Using the EMFISIS instrument on board the Van Allen Probes, electron densities are extracted from the upper hybrid resonance to an uncertainty of 10%. Some measurements are subject to larger errors given interpretational issues, especially at low densities (L > 4) resulting from geomagnetic activity. At high densities EMFISIS is restricted by an upper observable limit near 3000 cm-3. As this limit is encountered above perigee, we employ two additional methods validated against EMFISIS measurements to determine electron densities deep within the plasmasphere (L < 2). EMFISIS can extrapolate density estimates to lower L by calculating high densities, in good agreement with the upper hybrid technique when applicable, from plasma wave properties. Calibrated measurements, from the Van Allen Probes EFW potential instrument, also extend into this range. In comparison with the published EMFISIS database we provide a metric for the validity of core plasmaspheric density measurements obtained from these methods and an empirical density model for use in wave and particle simulations.

  20. Near-Unity Absorption in van der Waals Semiconductors for Ultrathin Optoelectronics.

    PubMed

    Jariwala, Deep; Davoyan, Artur R; Tagliabue, Giulia; Sherrott, Michelle C; Wong, Joeson; Atwater, Harry A

    2016-09-14

    We demonstrate near-unity, broadband absorbing optoelectronic devices using sub-15 nm thick transition metal dichalcogenides (TMDCs) of molybdenum and tungsten as van der Waals semiconductor active layers. Specifically, we report that near-unity light absorption is possible in extremely thin (<15 nm) van der Waals semiconductor structures by coupling to strongly damped optical modes of semiconductor/metal heterostructures. We further fabricate Schottky junction devices using these highly absorbing heterostructures and characterize their optoelectronic performance. Our work addresses one of the key criteria to enable TMDCs as potential candidates to achieve high optoelectronic efficiency.

  1. Simulated Van Allen Belts Generated by Plasma Thruster in Tank 5

    NASA Image and Video Library

    1966-09-21

    The model of the Earth housed inside Vacuum Tank 5 contained a coil which produced a magnetic field simulating that of the Earth. It was bombarded with a stream of ionized particles simulating the solar wind which impinges on the Earth's magnetic field. The bands or belts of luminous plasma seen in this image were suggestive of the Van Allen belts found around the Earth. Scientists at Lewis probed the plasma around the model and studied scaling laws in an attempt to find an explanation for the actual formation of the Van Allen belt.

  2. 78 FR 47817 - Parts and Accessories Necessary for Safe Operation; Application for an Exemption From Van Hool N...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-06

    ....V. and Coach USA AGENCY: Federal Motor Carrier Safety Administration (FMCSA), DOT. ACTION: Notice of... exemption from Van Hool N.V. and Coach USA (Van Hool/Coach USA) to allow the use of double deck motorcoaches..., Van Hool/Coach USA is requesting an exemption that would allow the use of sleeper berths that comply...

  3. Bernard van Leer Foundation. Annual Report 1997.

    ERIC Educational Resources Information Center

    Bernard Van Leer Foundation, The Hague (Netherlands).

    This document provides an annual report and financial review of the Bernard van Leer Foundation, a private institution created in 1949 for broad humanitarian purposes. Following an introduction by the chairman of the Foundation's board of trustees, a report of the executive director details the first full-year of implementation of the Foundation's…

  4. Bernard van Leer Foundation Annual Report 1996.

    ERIC Educational Resources Information Center

    Bernard Van Leer Foundation, The Hague (Netherlands).

    This document provides an annual report and financial review for 1996 of the Bernard van Leer Foundation, a private institution created in 1949 for broad humanitarian purposes. Following a summary by the executive director of the Foundation, the report includes a description of the foundation and its grants. It then lists, by country, the major…

  5. Mechanisms of Resistance in Microbial Spores.

    DTIC Science & Technology

    1986-11-14

    1702 by Leeuwenhoek with rotifers and nematodes. Cryptobiosis occurs also in the primitive tardigrade animals, the cysts and larvae of certain...excellent unicelTular, prokaryotic model for studying the extended maintenance of the organized structure that characterizes living organisms. Despite

  6. A notable difference between ideal gas and infinite molar volume limit of van der Waals gas

    NASA Astrophysics Data System (ADS)

    Liu, Q. H.; Shen, Y.; Bai, R. L.; Wang, X.

    2010-05-01

    The van der Waals equation of state does not sufficiently represent a gas unless a thermodynamic potential with two proper and independent variables is simultaneously determined. The limiting procedures under which the behaviour of the van der Waals gas approaches that of an ideal gas are letting two van der Waals coefficients be zero rather than letting the molar volume become infinitely large; otherwise, the partial derivative of internal energy with respect to pressure at a fixed temperature does not vanish.

  7. Self-Aligned van der Waals Heterojunction Diodes and Transistors.

    PubMed

    Sangwan, Vinod K; Beck, Megan E; Henning, Alex; Luo, Jiajia; Bergeron, Hadallia; Kang, Junmo; Balla, Itamar; Inbar, Hadass; Lauhon, Lincoln J; Hersam, Mark C

    2018-02-14

    A general self-aligned fabrication scheme is reported here for a diverse class of electronic devices based on van der Waals materials and heterojunctions. In particular, self-alignment enables the fabrication of source-gated transistors in monolayer MoS 2 with near-ideal current saturation characteristics and channel lengths down to 135 nm. Furthermore, self-alignment of van der Waals p-n heterojunction diodes achieves complete electrostatic control of both the p-type and n-type constituent semiconductors in a dual-gated geometry, resulting in gate-tunable mean and variance of antiambipolar Gaussian characteristics. Through finite-element device simulations, the operating principles of source-gated transistors and dual-gated antiambipolar devices are elucidated, thus providing design rules for additional devices that employ self-aligned geometries. For example, the versatility of this scheme is demonstrated via contact-doped MoS 2 homojunction diodes and mixed-dimensional heterojunctions based on organic semiconductors. The scalability of this approach is also shown by fabricating self-aligned short-channel transistors with subdiffraction channel lengths in the range of 150-800 nm using photolithography on large-area MoS 2 films grown by chemical vapor deposition. Overall, this self-aligned fabrication method represents an important step toward the scalable integration of van der Waals heterojunction devices into more sophisticated circuits and systems.

  8. Molecular Characterization of Enterococcus faecalis N06-0364 with Low-Level Vancomycin Resistance Harboring a Novel d-Ala-d-Ser Gene Cluster, vanL▿

    PubMed Central

    Boyd, David A.; Willey, Barbara M.; Fawcett, Darlene; Gillani, Nazira; Mulvey, Michael R.

    2008-01-01

    Enterococcus faecalis N06-0364, exhibiting a vancomycin MIC of 8 μg/ml, was found to harbor a novel d-Ala-d-Ser gene cluster, designated vanL. The vanL gene cluster was similar in organization to the vanC operon, but the VanT serine racemase was encoded by two separate genes, vanTmL (membrane binding) and vanTrL (racemase). PMID:18458129

  9. Isotope engineering of van der Waals interactions in hexagonal boron nitride

    NASA Astrophysics Data System (ADS)

    Vuong, T. Q. P.; Liu, S.; van der Lee, A.; Cuscó, R.; Artús, L.; Michel, T.; Valvin, P.; Edgar, J. H.; Cassabois, G.; Gil, B.

    2018-02-01

    Hexagonal boron nitride is a model lamellar compound where weak, non-local van der Waals interactions ensure the vertical stacking of two-dimensional honeycomb lattices made of strongly bound boron and nitrogen atoms. We study the isotope engineering of lamellar compounds by synthesizing hexagonal boron nitride crystals with nearly pure boron isotopes (10B and 11B) compared to those with the natural distribution of boron (20 at% 10B and 80 at% 11B). On the one hand, as with standard semiconductors, both the phonon energy and electronic bandgap varied with the boron isotope mass, the latter due to the quantum effect of zero-point renormalization. On the other hand, temperature-dependent experiments focusing on the shear and breathing motions of adjacent layers revealed the specificity of isotope engineering in a layered material, with a modification of the van der Waals interactions upon isotope purification. The electron density distribution is more diffuse between adjacent layers in 10BN than in 11BN crystals. Our results open perspectives in understanding and controlling van der Waals bonding in layered materials.

  10. Isotope engineering of van der Waals interactions in hexagonal boron nitride.

    PubMed

    Vuong, T Q P; Liu, S; Van der Lee, A; Cuscó, R; Artús, L; Michel, T; Valvin, P; Edgar, J H; Cassabois, G; Gil, B

    2018-02-01

    Hexagonal boron nitride is a model lamellar compound where weak, non-local van der Waals interactions ensure the vertical stacking of two-dimensional honeycomb lattices made of strongly bound boron and nitrogen atoms. We study the isotope engineering of lamellar compounds by synthesizing hexagonal boron nitride crystals with nearly pure boron isotopes ( 10 B and 11 B) compared to those with the natural distribution of boron (20 at% 10 B and 80 at% 11 B). On the one hand, as with standard semiconductors, both the phonon energy and electronic bandgap varied with the boron isotope mass, the latter due to the quantum effect of zero-point renormalization. On the other hand, temperature-dependent experiments focusing on the shear and breathing motions of adjacent layers revealed the specificity of isotope engineering in a layered material, with a modification of the van der Waals interactions upon isotope purification. The electron density distribution is more diffuse between adjacent layers in 10 BN than in 11 BN crystals. Our results open perspectives in understanding and controlling van der Waals bonding in layered materials.

  11. Inflationary universe in terms of a van der Waals viscous fluid

    NASA Astrophysics Data System (ADS)

    Brevik, I.; Elizalde, E.; Odintsov, S. D.; Timoshkin, A. V.

    The inflationary expansion of our early-time universe is considered in terms of the van der Waals equation, as equation of state for the cosmic fluid, where a bulk viscosity contribution is assumed to be present. The corresponding gravitational equations for the energy density in a homogeneous and isotropic Friedmann-Lemaître-Robertson-Walker universe are solved, and an analytic expression for the scale factor is obtained. Attention is paid, specifically, to the role of the viscosity term in the accelerated expansion; the values of the slow-roll parameters, the spectral index, and the tensor-to-scalar ratio for the van der Waals model are calculated and compared with the most recent astronomical data from the Planck satellite. By imposing reasonable restrictions on the parameters of the van der Waals equation, in the presence of viscosity, it is shown to be possible for this model to comply quite precisely with the observational data. One can therefore conclude that the inclusion of viscosity in the theory of the inflationary epoch may definitely improve the cosmological models.

  12. Automated Identification and Shape Analysis of Chorus Elements in the Van Allen Radiation Belts

    NASA Astrophysics Data System (ADS)

    Sen Gupta, Ananya; Kletzing, Craig; Howk, Robin; Kurth, William; Matheny, Morgan

    2017-12-01

    An important goal of the Van Allen Probes mission is to understand wave-particle interaction by chorus emissions in terrestrial Van Allen radiation belts. To test models, statistical characterization of chorus properties, such as amplitude variation and sweep rates, is an important scientific goal. The Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) instrumentation suite provides measurements of wave electric and magnetic fields as well as DC magnetic fields for the Van Allen Probes mission. However, manual inspection across terabytes of EMFISIS data is not feasible and as such introduces human confirmation bias. We present signal processing techniques for automated identification, shape analysis, and sweep rate characterization of high-amplitude whistler-mode chorus elements in the Van Allen radiation belts. Specifically, we develop signal processing techniques based on the radon transform that disambiguate chorus elements with a dominant sweep rate against hiss-like chorus. We present representative results validating our techniques and also provide statistical characterization of detected chorus elements across a case study of a 6 s epoch.

  13. Structuring of the Renewed Decision Making Process in the Royal Netherlands Army (Structurering van het vernieuwde besluitvormingsproces binnen de KL).

    DTIC Science & Technology

    1996-10-10

    time informatie wordt door Eisenhardt (1989) gedefinieerd als " information about a firm’s operations or environment for which there is little or no...op het invoeren van (getypte) tekst . Conclusie Elektronisch Brainstormen: * in principe geschikt om Eigen Mogelijkheden te genereren, vooral als de...Capaieairt ca •acitenit ca a• C ie•lit Fig. 1 Mogelijke wijzen van besluitvorming (zie tekst ) als functie van beschik- bare tijd, capaciteit en ervaring van

  14. Evaluatie Kennistechnologische Ondersteuning bij Diagnose van SEWACO systemen (Projectmanagementplan) (Evaluation of Knowledge Technological Support for Diagnosis of SEWACO Systems (Project Management Plan)

    DTIC Science & Technology

    1991-08-01

    diagnos van SE WACO systmnen/ AD-A245 424111 1fl1,l Niets uit deze uitgave mag warden vermenigvuldligd en/of oPenbaar gemaakt door middel van druk...fotakopie. microfilm of op welks andere whlze dan ook, zonder voorafgaande toeslemming van TNO. Hot ter inzage geven van het TNO-rapport aan direct...belanghebbenden is tegestaan. HYP. vanl OC dt Indian dit rapport in opdracht ward uitgebracht, wordt voor de, rechten en verpiichtingen van opdrachtgever en

  15. Phase-Defined van der Waals Schottky Junctions with Significantly Enhanced Thermoelectric Properties.

    PubMed

    Wang, Qiaoming; Yang, Liangliang; Zhou, Shengwen; Ye, Xianjun; Wang, Zhe; Zhu, Wenguang; McCluskey, Matthew D; Gu, Yi

    2017-07-06

    We demonstrate a van der Waals Schottky junction defined by crystalline phases of multilayer In 2 Se 3 . Besides ideal diode behaviors and the gate-tunable current rectification, the thermoelectric power is significantly enhanced in these junctions by more than three orders of magnitude compared with single-phase multilayer In 2 Se 3 , with the thermoelectric figure-of-merit approaching ∼1 at room temperature. Our results suggest that these significantly improved thermoelectric properties are not due to the 2D quantum confinement effects but instead are a consequence of the Schottky barrier at the junction interface, which leads to hot carrier transport and shifts the balance between thermally and field-driven currents. This "bulk" effect extends the advantages of van der Waals materials beyond the few-layer limit. Adopting such an approach of using energy barriers between van der Waals materials, where the interface states are minimal, is expected to enhance the thermoelectric performance in other 2D materials as well.

  16. Van der Waals interaction mediated by an optically uniaxial layer

    NASA Astrophysics Data System (ADS)

    Šarlah, A.; Žumer, S.

    2001-11-01

    We study the van der Waals interaction between macroscopic bodies separated by a thin anisotropic film with a uniaxial permittivity tensor. We describe the effect of anisotropy of the media on the magnitude and sign of the interaction. The resulting differences in the van der Waals interaction are especially important for the stability of strongly confined liquid crystals, and nanostructures characterized by highly uniaxial macroscopic molecular arrangement, such as in self-assemblies of long organic molecules forming films, membranes, colloids, etc. We introduce an improved expression for the Hamaker constant which takes into account the uniaxial symmetry of a medium. In special cases neglecting the optical anisotropy even leads to an incorrect sign of the interaction.

  17. Teaching Strategies of the van Dijk Curricular Approach.

    ERIC Educational Resources Information Center

    MacFarland, S. Z. C.

    1995-01-01

    This article presents 14 major teaching strategies for implementing the Jan van Dijk curricular approach with children who are deaf-blind. The theory underlying the approach is reported, and guidelines for implementing instructional strategies in the areas of communication, socialization, conceptualization, and movement are discussed. (Author/DB)

  18. Vibration-rotation-tunneling spectroscopy of the van der Waals Bond: A new look at intermolecular forces

    SciTech Connect

    Cohen, R.C.; Saykally, R.J.

    Measurements of the low-frequency van der Waals vibrations in weakly bound complexes by high-resolution laser spectroscopy provide a means to probe intermolecular forces at unprecedented levels of detail and precision. Several new methods are presently being used to record vibration/rotation-tunneling (VRT) transitions associated with the motions of the weak bonds in van der Waals clusters. The most direct measurements are those probing only the van der Waals modes themselves, which occur at far-infrared wavelengths. This article presents a review of the information on both intramolecular forces and intramolecular dynamics that has been obtained from far-infrared VRT spectra of 18 complexesmore » during the past several years. Some rotationally resolved measurements of van der Waals modes observed in combination with electronic or vibrational excitation are also discussed. 185 refs., 15 figs., 1 tab.« less

  19. A novel method for simultaneous Enterococcus species identification/typing and van genotyping by high resolution melt analysis.

    PubMed

    Gurtler, Volker; Grando, Danilla; Mayall, Barrie C; Wang, Jenny; Ghaly-Derias, Shahbano

    2012-09-01

    In order to develop a typing and identification method for van gene containing Enterococcus faecium, two multiplex PCR reactions were developed for use in HRM-PCR (High Resolution Melt-PCR): (i) vanA, vanB, vanC, vanC23 to detect van genes from different Enterococcus species; (ii) ISR (intergenic spacer region between the 16S and 23S rRNA genes) to detect all Enterococcus species and obtain species and isolate specific HRM curves. To test and validate the method three groups of isolates were tested: (i) 1672 Enterococcus species isolates from January 2009 to December 2009; (ii) 71 isolates previously identified and typed by PFGE (pulsed-field gel electrophoresis) and MLST (multi-locus sequence typing); and (iii) 18 of the isolates from (i) for which ISR sequencing was done. As well as successfully identifying 2 common genotypes by HRM from the Austin Hospital clinical isolates, this study analysed the sequences of all the vanB genes deposited in GenBank and developed a numerical classification scheme for the standardised naming of these vanB genotypes. The identification of Enterococcus faecalis from E. faecium was reliable and stable using ISR PCR. The typing of E. faecium by ISR PCR: (i) detected two variable peaks corresponding to different copy numbers of insertion sequences I and II corresponding to peak I and II respectively; (ii) produced 7 melt profiles for E. faecium with variable copy numbers of sequences I and II; (iii) demonstrated stability and instability of peak heights with equal frequency within the patient sample (36.4±4.5 days and 38.6±5.8 days respectively for 192 patients); (iv) detected ISR-HRM types with as much discrimination as PFGE and more than MLST; and (v) detected ISR-HRM types that differentiated some isolates that were identical by PFGE and MLST. In conjunction with the rapid and accurate van genotyping method described here, this ISR-HRM typing and identification method can be used as a stable identification and typing method with

  20. Characterization and modelling of VanT: a novel, membrane-bound, serine racemase from vancomycin-resistant Enterococcus gallinarum BM4174.

    PubMed

    Arias, C A; Martín-Martinez, M; Blundell, T L; Arthur, M; Courvalin, P; Reynolds, P E

    1999-03-01

    Sequence determination of a region downstream from the vanXYc gene in Enterococcus gallinarum BM4174 revealed an open reading frame, designated vanT, that encodes a 698-amino-acid polypeptide with an amino-terminal domain containing 10 predicted transmembrane segments. The protein contained a highly conserved pyridoxal phosphate attachment site in the C-terminal domain, typical of alanine racemases. The protein was overexpressed in Escherichia coli, and serine racemase activity was detected in the membrane but not in the cytoplasmic fraction after centrifugation of sonicated cells, whereas alanine racemase activity was located almost exclusively in the cytoplasm. When the protein was overexpressed as a polypeptide lacking the predicted transmembrane domain, serine racemase activity was detected in the cytoplasm. The serine racemase activity was partially (64%) inhibited by D-cycloserine, whereas host alanine racemase activity was almost totally inhibited (97%). Serine racemase activity was also detected in membrane preparations of constitutively vancomycin-resistant E. gallinarum BM4174 but not in BM4175, in which insertional inactivation of the vanC-1 D-Ala:D-Ser ligase gene probably had a polar effect on expression of the vanXYc and vanT genes. Comparative modelling of the deduced C-terminal domain was based on the alignment of VanT with the Air alanine racemase from Bacillus stearothermophilus. The model revealed that almost all critical amino acids in the active site of Air were conserved in VanT, indicating that the C-terminal domain of VanT is likely to adopt a three-dimensional structure similar to that of Air and that the protein could exist as a dimer. These results indicate that the source of D-serine for peptidoglycan synthesis in vancomycin-resistant enterococci expressing the VanC phenotype involves racemization of L- to D-serine by a membrane-bound serine racemase.

  1. Geometrothermodynamics of Van der Waals black hole

    NASA Astrophysics Data System (ADS)

    Hu, Yumin; Chen, Juhua; Wang, Yongjiu

    2017-12-01

    We study the geometrothermodynamics of a special asymptotically AdS black hole, i.e. Van der Waals ( VdW) black hole, in the extended phase space where the negative cosmological constant Λ can be regarded as thermodynamic pressure. Analysing some special conditions of this black hole with geometrothermodynamical method, we find a good correlation with ordinary cases according to the state equation.

  2. Bio-Aerosol Testkamer: Ontwikkeling van Protocollen (Bio Aerosol Test Chamber: Development of Protocols)

    DTIC Science & Technology

    2007-07-01

    testfaciliteit detector met de drie simulanten getest beschikbaar gekomen voor het testen van Beschrijving van de worden volgens gangbare internationale bio...2005 werd de Bio-Adrosol Testkamer (BAT-kamer) geplaatst door de firma Dycor Technologies Ltd., Canada. In de BAT-kamner kan een bio-ai5rosol...bestaande ruimte past. In beide gevallen bleek de firma Dycor Technologies Ltd in Canada (http://www.dycor.com) de beste leverancier te zijn, en voor beide

  3. 49 CFR 393.128 - What are the rules for securing automobiles, light trucks and vans?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 5 2013-10-01 2013-10-01 false What are the rules for securing automobiles, light... automobiles, light trucks and vans? (a) Applicability. The rules in this section apply to the transportation of automobiles, light trucks, and vans which individually weigh 4,536 kg. (10,000 lb) or less...

  4. 49 CFR 393.128 - What are the rules for securing automobiles, light trucks and vans?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 5 2010-10-01 2010-10-01 false What are the rules for securing automobiles, light... automobiles, light trucks and vans? (a) Applicability. The rules in this section apply to the transportation of automobiles, light trucks, and vans which individually weigh 4,536 kg. (10,000 lb) or less...

  5. 49 CFR 393.128 - What are the rules for securing automobiles, light trucks and vans?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 5 2012-10-01 2012-10-01 false What are the rules for securing automobiles, light... automobiles, light trucks and vans? (a) Applicability. The rules in this section apply to the transportation of automobiles, light trucks, and vans which individually weigh 4,536 kg. (10,000 lb) or less...

  6. 49 CFR 393.128 - What are the rules for securing automobiles, light trucks and vans?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 5 2014-10-01 2014-10-01 false What are the rules for securing automobiles, light... automobiles, light trucks and vans? (a) Applicability. The rules in this section apply to the transportation of automobiles, light trucks, and vans which individually weigh 4,536 kg. (10,000 lb) or less...

  7. 49 CFR 393.128 - What are the rules for securing automobiles, light trucks and vans?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 5 2011-10-01 2011-10-01 false What are the rules for securing automobiles, light... automobiles, light trucks and vans? (a) Applicability. The rules in this section apply to the transportation of automobiles, light trucks, and vans which individually weigh 4,536 kg. (10,000 lb) or less...

  8. 46 CFR 194.10-15 - Magazine van construction.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Magazine van construction. 194.10-15 Section 194.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS HANDLING... system shall be of watertight construction and bear a label plate denoting the power requirement of the...

  9. 12 & 15 passenger vans tire pressure study : preliminary results

    DOT National Transportation Integrated Search

    2005-05-01

    A study was conducted by the National Highway Traffic Safety Administration's (NHTSA's) National Center for Statistics and Analysis (NCSA) to determine the extent of underinflation and observe the tire condition in 12- and 15-passenger vans. This Res...

  10. Dancing bunches as Van Kampen modes

    SciTech Connect

    Burov, A.; /Fermilab

    2011-03-01

    Van Kampen modes are eigen-modes of Jeans-Vlasov equation [1-3]. Their spectrum consists of continuous and, possibly, discrete parts. Onset of a discrete van Kampen mode means emergence of a coherent mode without any Landau damping; thus, even a tiny couple-bunch wake is sufficient to drive instability. Longitudinal instabilities observed at Tevatron [4], RHIC [5] and SPS [6] can be explained as loss of Landau damping (LLD), which is shown here to happen at fairly low impedances. For repulsive wakes and single-harmonic RF, LLD is found to be extremely sensitive to steepness of the bunch distribution function at small amplitudes. Basedmore » on that, a method of beam stabilization is suggested. Emergence of a discrete van Kampen mode means either loss of Landau damping or instability. Longitudinal bunch stability is analysed in weak head-tail approximation for inductive impedance and single-harmonic RF. The LLD threshold intensities are found to be rather low: for cases under study all of them do not exceed a few percent of the zero-amplitude incoherent synchrotron frequency shift, strongly decreasing for shorter bunches. Because of that, LLD can explain longitudinal instabilities happened at fairly low impedances at Tevatron [4], and possibly for RHIC [5] and SPS [6], being in that sense an alternative to the soliton explanation [5, 20]. Although LLD itself results in many cases in emergence of a mode with zero growth rate, any couple-bunch (and sometimes multi-turn) wake would drive instability for that mode, however small this wake is. LLD is similar to a loss of immune system of a living cell, when any microbe becomes fatal for it. The emerging discrete mode is normally very different from the rigid-bunch motion; thus the rigid-mode model significantly overestimates the LLD threshold. The power low of LLD predicted in Ref. [17] agrees with results of this paper. However, the numerical factor in that scaling low strongly depends on the bunch distribution

  11. Spin-Flavor van der Waals Forces and NN interaction

    SciTech Connect

    Alvaro Calle Cordon, Enrique Ruiz Arriola

    A major goal in Nuclear Physics is the derivation of the Nucleon-Nucleon (NN) interaction from Quantum Chromodynamics (QCD). In QCD the fundamental degrees of freedom are colored quarks and gluons which are confined to form colorless strongly interacting hadrons. Because of this the resulting nuclear forces at sufficiently large distances correspond to spin-flavor excitations, very much like the dipole excitations generating the van der Waals (vdW) forces acting between atoms. We study the Nucleon-Nucleon interaction in the Born-Oppenheimer approximation at second order in perturbation theory including the Delta resonance as an intermediate state. The potential resembles strongly chiral potentials computedmore » either via soliton models or chiral perturbation theory and has a van der Waals like singularity at short distances which is handled by means of renormalization techniques. Results for the deuteron are discussed.« less

  12. IVAN: Intelligent Van for the Distribution of Pharmaceutical Drugs

    PubMed Central

    Moreno, Asier; Angulo, Ignacio; Perallos, Asier; Landaluce, Hugo; Zuazola, Ignacio Julio García; Azpilicueta, Leire; Astrain, José Javier; Falcone, Francisco; Villadangos, Jesús

    2012-01-01

    This paper describes a telematic system based on an intelligent van which is capable of tracing pharmaceutical drugs over delivery routes from a warehouse to pharmacies, without altering carriers' daily conventional tasks. The intelligent van understands its environment, taking into account its location, the assets and the predefined delivery route; with the capability of reporting incidences to carriers in case of failure according to the established distribution plan. It is a non-intrusive solution which represents a successful experience of using smart environments and an optimized Radio Frequency Identification (RFID) embedded system in a viable way to resolve a real industrial need in the pharmaceutical industry. The combination of deterministic modeling of the indoor vehicle, the implementation of an ad-hoc radiating element and an agile software platform within an overall system architecture leads to a competitive, flexible and scalable solution. PMID:22778659

  13. The Educational Thought of Cornelius Van Til: Philosophical Foundations of the Contemporary Christian School Movement.

    ERIC Educational Resources Information Center

    Maffet, Gregory J.; Dye, Charles M.

    This paper gives an account of the thoughts of Cornelius Van Til on the contemporary Christian school movement. An account of the historical development of Christian compromise is given, followed by a critique of the compromise among contemporary Christian educators. Van Til claims that any educational position which falls short of being founded…

  14. Unconscious Odour Conditioning 25 Years Later: Revisiting and Extending "Kirk-Smith, Van Toller and Dodd"

    ERIC Educational Resources Information Center

    Zucco, Gesualdo M.; Paolini, Michela; Schaal, Benoist

    2009-01-01

    The pioneering work by Kirk-Smith, Van Toller, and Dodd [Kirk-Smith, M. D., Van Toller, C., & Dodd, G. H. (1983). "Unconscious odour conditioning in human subjects." "Biological Psychology," 17, 221-231], established that an unnoticed odorant paired with an emotionally meaningful task can influence mood and attitudes when the odorant alone is…

  15. A high-pressure van der Waals compound in solid nitrogen-helium mixtures

    NASA Technical Reports Server (NTRS)

    Vos, W. L.; Finger, L. W.; Hemley, R. J.; Hu, J. Z.; Mao, H. K.; Schouten, J. A.

    1992-01-01

    A detailed diamond anvil-cell study using synchrotron X-ray diffraction, Raman scattering, and optical microscopy has been conducted for the He-N system, with a view to the weakly-bound van der Waals molecule interactions that can be formed in the gas phase. High pressure is found to stabilize the formation of a stoichiometric, solid van der Waals compound of He(N2)11 composition which may exemplify a novel class of compounds found at high pressures in the interiors of the outer planets and their satellites.

  16. VIEW NORTH, SHOWING SOUTH END OF BRIDGE LOOKING TOWARD VAN ...

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

    VIEW NORTH, SHOWING SOUTH END OF BRIDGE LOOKING TOWARD VAN BUREN TOWNSHIP - Belleville Road Bridge, Spanning the Flat River at Burroughs Drive (replaced Burroughs Street Bridge), Lowell, Kent County, MI

  17. Learning Styles versus the Rip Van Winkle Syndrome.

    ERIC Educational Resources Information Center

    Orsak, Lana

    1990-01-01

    Rip Van Winkle would not recognize Corsicana (Texas) High School since its curriculum coordinator began implementing learning styles techniques in various pilot programs. Lecturing to rows of bored students has been replaced by students' active involvement in group activities, listening centers, and tactile/kinesthetic exercises on the floor or at…

  18. A 600,000 year long continental pollen record from Lake Van, eastern Turkey

    NASA Astrophysics Data System (ADS)

    Litt, T.; Pickarski, N.; Heumann, G.

    2014-12-01

    Lake Van is the fourth largest terminal lake in the world (38.5°N, 43 °E, volume 607 km3, area 3570 km2, maximum water depth 460 m), extending for 130 km WSW-ENE on the Eastern Anatolian High Plateau, Turkey. The sedimentary record of Lake Van, partly laminated, obtains a long and continuous continental sequence that covers multiple interglacial-glacial cycles. Promoted by the potential of the sedimentary sequence for reconstructing the paleoecological and paleoclimate development of the Near East, a deep drilling operation was carried out in 2010 supported by the International Continental Scientific Drilling Program (ICDP). The 119 m long continental record is based on a well-dated composite profile drilled on the so-called Ahlat Ridge in water depth of 360 m encompassing the last 600,000 years. It contains the longest continuous continental pollen record of the Quaternary in the entire Near East and central Asia obtained to date. It documents glacial and interglacial stages as well as pronounced interstadials encompassing the entire 600 ka of the sedimentary record. The cold-adapted vegetation in the Lake Van region during glacial stages and stadial substages can be described as dwarf-shrub steppe and desert steppe very similar to each other. The climax vegetation of the interglacial stages in the Lake Van region is characterized by an oak steppe-forest with pistachio and juniper. It is interesting to note that, in contrast to the atmospheric CO2 concentration from Antarctic ice cores or marine isotope values based on benthic foraminifera, there is no clear subdivision in the Lake Van pollen record between low-amplitude interglacials (cooler cycles) prior the mid-Brunhes event (MBE) at 430 ka and high-amplitude, post MBE interglacials. Lower CO2 concentrations in the atmosphere might be compensated by stronger insolation forcing during Marine Isotope Stages (MIS) 13a and 15a. A similar pattern can be observed during the triplicate interglacial complex MIS 7

  19. Dispersion of the Vancomycin Resistance Genes vanA and vanC of Enterococcus Isolated from Nile Tilapia on Retail Sale: A Public Health Hazard.

    PubMed

    Osman, Kamelia M; Ali, Mohamed N; Radwan, Ismail; ElHofy, Fatma; Abed, Ahmed H; Orabi, Ahmed; Fawzy, Nehal M

    2016-01-01

    Although normally regarded harmless commensals, enterococci may cause a range of different infections in humans, including urinary tract infections, sepsis, and endocarditis. The acquisition of vancomycin resistance by enterococci (VRE) has seriously affected the treatment and infection control of these organisms. VRE are frequently resistant to all antibiotics that are effective treatment for vancomycin-susceptible enterococci, which leaves clinicians treating VRE infections with limited therapeutic options. With VRE emerging as a global threat to public health, we aimed to isolate, identify enterococci species from tilapia and their resistance to van-mediated glycopeptide (vanA and vanC) as well as the presence of enterococcal surface protein (esp) using conventional and molecular methods. The cultural, biochemical (Vitek 2 system) and polymerase chain reaction results revealed eight Enterococcus isolates from the 80 fish samples (10%) to be further identified as E. faecalis (6/8, 75%) and E gallinarum (2/8, 25%). Intraperitoneal injection of healthy Nile tilapia with the eight Enterococcus isolates caused significant morbidity (70%) within 3 days and 100% mortality at 6 days post-injection with general signs of septicemia. All of the eight Enterococcus isolates were found to be resistant to tetracycline. The 6/6 E. faecalis isolates were susceptible for penicillin, nitrofurantoin, gentamicin, and streptomycin. On the other hand 5/6 were susceptible for ampicillin, vancomycin, chloramphenicol, and ciprofloxacin. The two isolates of E. gallinarum were sensitive to rifampicin and ciprofloxacin and resistant to vancomycin, chloramphenicol, and erythromycin. Molecular characterization proved that they all presented the prototypic vanC element. On the whole, one of the two vancomycin resistance gene was present in 3/8 of the enterococci isolates, while the esp virulence gene was present in 1/8 of the enterococci isolates. The results in this study emphasize the

  20. Serine and alanine racemase activities of VanT: a protein necessary for vancomycin resistance in Enterococcus gallinarum BM4174.

    PubMed

    Arias, C A; Weisner, J; Blackburn, J M; Reynolds, P E

    2000-07-01

    Vancomycin resistance in Enterococcus gallinarum results from the production of UDP-MurNAc-pentapeptide[D-Ser]. VanT, a membrane-bound serine racemase, is one of three proteins essential for this resistance. To investigate the selectivity of racemization of L-Ser or L-Ala by VanT, a strain of Escherichia coli TKL-10 that requires D-Ala for growth at 42 degrees C was used as host for transformation experiments using plasmids containing the full-length vanT from Ent. gallinarum or the alanine racemase gene (alr) of Bacillus stearothermophilus: both plasmids were able to complement E. coli TKL-10 at 42 degrees C. No alanine or serine racemase activities were detected in the host strain E. coli TKL-10 grown at 30, 34 or 37 degrees C. Serine and alanine racemase activities were found almost exclusively (96%) in the membrane fraction of E. coli TKL-10/pCA4(vanT): the alanine racemase activity of VanT was 14% of the serine racemase activity in both E. coli TKL-10/pCA4(vanT) and E. coli XL-1 Blue/pCA4(vanT). Alanine racemase activity was present mainly (95%) in the cytoplasmic fraction of E. coli TKL-10/pJW40(alr), with a trace (1.6%) of serine racemase activity. Additionally, DNA encoding the soluble domain of VanT was cloned and expressed in E. coli M15 as a His-tagged polypeptide and purified: this polypeptide also exhibited both serine and alanine racemase activities; the latter was approximately 18% of the serine racemase activity, similar to that of the full-length, membrane-bound enzyme. N-terminal sequencing of the purified His-tagged polypeptide revealed a single amino acid sequence, indicating that the formation of heterodimers between subunits of His-tagged C-VanT and endogenous alanine racemases from E. coli was unlikely. The authors conclude that the membrane-bound serine racemase VanT also has alanine racemase activity but is able to racemize serine more efficiently than alanine, and that the cytoplasmic domain is responsible for the racemase activity.

  1. Martin Van Buren National Historic Site alternative transportation feasibility study.

    DOT National Transportation Integrated Search

    2012-05-31

    The Martin Van Buren National Historic Site (MVBNHS) Alternative Transportation Feasibility Study examines the feasibility of : alternative transportation system (ATS) service to MVBNHS. The report investigates opportunities for a shuttle carrying vi...

  2. Accurate van der Waals force field for gas adsorption in porous materials.

    PubMed

    Sun, Lei; Yang, Li; Zhang, Ya-Dong; Shi, Qi; Lu, Rui-Feng; Deng, Wei-Qiao

    2017-09-05

    An accurate van der Waals force field (VDW FF) was derived from highly precise quantum mechanical (QM) calculations. Small molecular clusters were used to explore van der Waals interactions between gas molecules and porous materials. The parameters of the accurate van der Waals force field were determined by QM calculations. To validate the force field, the prediction results from the VDW FF were compared with standard FFs, such as UFF, Dreiding, Pcff, and Compass. The results from the VDW FF were in excellent agreement with the experimental measurements. This force field can be applied to the prediction of the gas density (H 2 , CO 2 , C 2 H 4 , CH 4 , N 2 , O 2 ) and adsorption performance inside porous materials, such as covalent organic frameworks (COFs), zeolites and metal organic frameworks (MOFs), consisting of H, B, N, C, O, S, Si, Al, Zn, Mg, Ni, and Co. This work provides a solid basis for studying gas adsorption in porous materials. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  3. Letters from a suicide: Van Gogh and his sister.

    PubMed

    Lester, David

    2010-04-01

    An analysis of trends over a 3-yr. period in the letters of Vincent Van Gogh to his sister as the time of his suicide approached identified 8 trends, including an increase in words concerned with anxiety and words concerned with the past.

  4. Kwalificate/Classificatie van Explosieve Stoffen en Munitie. Rapport 2. Testontwikkeling (Qualification/Classification Explosive Materials and Munition. 2. Test Development)

    DTIC Science & Technology

    1992-11-01

    beschermkap van het apparaat af te halen , waardoor bij een eventuele ontsteking het energetisch materiaal (al dan niet brandend) weg kan springen. Tevens...TNO-DefensieonderzoekPr TN TNO-rapport Kwalificatielclassificatie van explosieve stoffen ~ PML 1992-68 en munitief Rapport ]I: Testontwikkeling...rapport Kwalificatielclassificatie van explosieve stoffen PML 1992-68 en munitie Rapport f1: Testontwikkeling november 1992 ~~- ExorrIaar no:- 1ýMI

  5. 11. Historic American Buildings Survey Cortlandt Van Dyke Hubbard, Photographer ...

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

    11. Historic American Buildings Survey Cortlandt Van Dyke Hubbard, Photographer October 1959 INTERIOR DETAIL OF FRAME CONSTRUCTION - White Meadow Farm, State Roads 290 & 262 (moved to Lewes, DE), Cool Spring, Sussex County, DE

  6. Van der Waals equation of state revisited: importance of the dispersion correction.

    PubMed

    de Visser, Sam P

    2011-04-28

    One of the most basic equations of state describing nonideal gases and liquids is the van der Waals equation of state, and as a consequence, it is generally taught in most first year undergraduate chemistry courses. In this work, we show that the constants a and b in the van der Waals equation of state are linearly proportional to the polarizability volume of the molecules in a gas or liquid. Using this information, a new thermodynamic one-parameter equation of state is derived that contains experimentally measurable variables and physics constants only. This is the first equation of state apart from the Ideal Gas Law that contains experimentally measurable variables and physics constants only, and as such, it may be a very useful and practical equation for the description of dilute gases and liquids. The modified van der Waals equation of state describes pV as the sum of repulsive and attractive intermolecular interaction energies that are represented by an exponential repulsion function between the electron clouds of the molecules and a London dispersion component, respectively. The newly derived equation of state is tested against experimental data for several gas and liquid examples, and the agreement is satisfactory. The description of the equation of state as a one-parameter function also has implications on other thermodynamic functions, such as critical parameters, virial coefficients, and isothermal compressibilities. Using our modified van der Waals equation of state, we show that all of these properties are a function of the molecular polarizability volume. Correlations of experimental data confirm the derived proportionalities.

  7. James Van Allen and His Namesake NASA Mission

    NASA Astrophysics Data System (ADS)

    Baker, D. N.; Hoxie, V. C.; Jaynes, A.; Kale, A.; Kanekal, S. G.; Li, X.; Reeves, G. D.; Spence, H. E.

    2013-12-01

    In many ways, James A. Van Allen defined and "invented" modern space research. His example showed the way for government-university partners to pursue basic research that also served important national and international goals. He was a tireless advocate for space exploration and for the role of space science in the spectrum of national priorities.

  8. Van der Waals interactions and the limits of isolated atom models at interfaces

    PubMed Central

    Kawai, Shigeki; Foster, Adam S.; Björkman, Torbjörn; Nowakowska, Sylwia; Björk, Jonas; Canova, Filippo Federici; Gade, Lutz H.; Jung, Thomas A.; Meyer, Ernst

    2016-01-01

    Van der Waals forces are among the weakest, yet most decisive interactions governing condensation and aggregation processes and the phase behaviour of atomic and molecular matter. Understanding the resulting structural motifs and patterns has become increasingly important in studies of the nanoscale regime. Here we measure the paradigmatic van der Waals interactions represented by the noble gas atom pairs Ar–Xe, Kr–Xe and Xe–Xe with a Xe-functionalized tip of an atomic force microscope at low temperature. Individual rare gas atoms were fixed at node sites of a surface-confined two-dimensional metal–organic framework. We found that the magnitude of the measured force increased with the atomic radius, yet detailed simulation by density functional theory revealed that the adsorption induced charge redistribution strengthened the van der Waals forces by a factor of up to two, thus demonstrating the limits of a purely atomic description of the interaction in these representative systems. PMID:27174162

  9. Dynamics of three coupled van der Pol oscillators with application to circadian rhythms

    NASA Astrophysics Data System (ADS)

    Rompala, Kevin; Rand, Richard; Howland, Howard

    2007-08-01

    In this work we study a system of three van der Pol oscillators. Two of the oscillators are identical, and are not directly coupled to each other, but rather are coupled via the third oscillator. We investigate the existence of the in-phase mode in which the two identical oscillators have the same behavior. To this end we use the two variable expansion perturbation method (also known as multiple scales) to obtain a slow flow, which we then analyze using the computer algebra system MACSYMA and the numerical bifurcation software AUTO. Our motivation for studying this system comes from the presence of circadian rhythms in the chemistry of the eyes. We model the circadian oscillator in each eye as a van der Pol oscillator. Although there is no direct connection between the two eyes, they are both connected to the brain, especially to the pineal gland, which is here represented by a third van der Pol oscillator.

  10. Leon Van Speybroeck Wins Astrophysics Bruno Rossi Prize

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Leon Van Speybroeck of the Harvard-Smithsonian Center for Astrophysics in Cambridge Massachusetts was awarded the 2002 Bruno Rossi Prize of the High-Energy Astrophysics Division of the American Astronomy Society. The Rossi Prize is an arnual recognition of significant contributions in high-energy astrophysics in honor of the Massachusetts Institute of Technology's late Professor Bruno Rossi, an authority on cosmic ray physics and a pioneer in the field of x-ray astronomy. Van Speybroeck, who led the effort to design and make the x-ray mirrors for NASA's premier Chandra X-Ray Observatory, was recognized for a career of stellar achievements in designing precision x-ray optics. As Telescope Scientist for Chandra, he has worked for more than 20 years with a team that includes scientists and engineers from the Harvard-Smithsonian, NASA's Marshall Space Flight Center, TRW, Inc., Huhes-Danbury (now B.F. Goodrich Aerospace), Optical Coating Laboratories, Inc., and Eastman-Kodak on all aspects of the x-ray mirror assembly that is the heart of the observatory.

  11. Alternative Fuels Data Center: Propane Vans Keep Kansas City Transportation

    Science.gov Websites

    anxiety. More recently, the company has been exploring dedicated-propane vehicles in Kansas City to ensure technologies and petroleum-use reduction strategies, then deployed bi-fuel vans; currently exploring dedicated

  12. A discussion of the socio-economic losses and shelter impacts from the Van, Turkey Earthquakes of October and November 2011

    NASA Astrophysics Data System (ADS)

    Daniell, J. E.; Khazai, B.; Wenzel, F.; Kunz-Plapp, T.; Vervaeck, A.; Muehr, B.; Markus, M.

    2012-04-01

    The Van earthquake in 2011 hit at 10:41 GMT (13:41 Local) on Sunday, October 23rd, 2011. It was a Mw7.1-7.3 event located at a depth of around 10 km with the epicentre located directly between Ercis (pop. 75,000) and Van (pop. 370,000). Since then, the CEDIM Forensic Analysis Group (using a team of seismologists, engineers, sociologists and meteorologists) and www.earthquake-report.com has reported and analysed on the Van event. In addition, many damaging aftershocks occurring after the main eventwere analysed including a major aftershock centered in Van-Edremit on November 9th, 2011, causing much additional losses. The province of Van has around 1.035 million people as of the last census. The Van province is one of the poorest in Turkey and has much inequality between the rural and urban centers with an average HDI (Human Development Index) around that of Bhutan or Congo. The earthquakes are estimated to have caused 604 deaths (23 October) and 40 deaths (9 November); mostly due to falling debris and house collapse). In addition, between 1 billion TRY to 4 billion TRY (approx. 555 million USD - 2.2 billion USD) is estimated as total economic losses. This represents around 17 to 66% of the provincial GDP of the Van Province (approx. 3.3 billion USD) as of 2011. From the CATDAT Damaging Earthquakes Database, major earthquakes such as this one have occurred in the year 1111 causing major damage and having a magnitude around 6.5-7. In the year 1646 or 1648, Van was again struck by a M6.7 quake killing around 2000 people. In 1881, a M6.3 earthquake near Van killed 95 people. Again, in 1941, a M5.9 earthquake affected Ercis and Van killing between 190 and 430 people. 1945-1946 as well as 1972 brought again damaging and casualty-bearing earthquakes to the Van province. In 1976, the Van-Muradiye earthquake struck the border region with a M7, killing around 3840 people and causing around 51,000 people to become homeless. Key immediate lessons from similar historic

  13. Evaluation of BBL CHROMagar VanRE for detection of vancomycin-resistant Enterococci in rectal swab specimens.

    PubMed

    Stamper, Paul D; Shulder, Stephanie; Bekalo, Pearl; Manandhar, Deepika; Ross, Tracy L; Speser, Sharon; Kingery, Julie; Carroll, Karen C

    2010-11-01

    A study was performed on 517 surveillance rectal swabs to evaluate a selective and differential chromogenic medium, the BBL CHROMagar VanRE (CVRE), which enables recovery and identification of VanA- and VanB-containing Enterococcus faecium (ENFM) and Enterococcus faecalis (ENFS) isolates. Compared to BBL Enterococcosel agar, a bile-esculin-azide-vancomycin (BEAV) agar, the initial overall sensitivity, specificity, and positive and negative predictive values of CVRE for the detection of vancomycin-resistant ENFM and ENFS were 99.1% and 94.8% and 84.2% and 99.7%, respectively. Among our patient population, more vancomycin-resistant enterococci (VRE) were recovered with CVRE than BEAV.

  14. Evaluation of BBL CHROMagar VanRE for Detection of Vancomycin-Resistant Enterococci in Rectal Swab Specimens▿

    PubMed Central

    Stamper, Paul D.; Shulder, Stephanie; Bekalo, Pearl; Manandhar, Deepika; Ross, Tracy L.; Speser, Sharon; Kingery, Julie; Carroll, Karen C.

    2010-01-01

    A study was performed on 517 surveillance rectal swabs to evaluate a selective and differential chromogenic medium, the BBL CHROMagar VanRE (CVRE), which enables recovery and identification of VanA- and VanB-containing Enterococcus faecium (ENFM) and Enterococcus faecalis (ENFS) isolates. Compared to BBL Enterococcosel agar, a bile-esculin-azide-vancomycin (BEAV) agar, the initial overall sensitivity, specificity, and positive and negative predictive values of CVRE for the detection of vancomycin-resistant ENFM and ENFS were 99.1% and 94.8% and 84.2% and 99.7%, respectively. Among our patient population, more vancomycin-resistant enterococci (VRE) were recovered with CVRE than BEAV. PMID:20739492

  15. Probing low-energy hyperbolic polaritons in van der Waals crystals with an electron microscope.

    PubMed

    Govyadinov, Alexander A; Konečná, Andrea; Chuvilin, Andrey; Vélez, Saül; Dolado, Irene; Nikitin, Alexey Y; Lopatin, Sergei; Casanova, Fèlix; Hueso, Luis E; Aizpurua, Javier; Hillenbrand, Rainer

    2017-07-21

    Van der Waals materials exhibit intriguing structural, electronic, and photonic properties. Electron energy loss spectroscopy within scanning transmission electron microscopy allows for nanoscale mapping of such properties. However, its detection is typically limited to energy losses in the eV range-too large for probing low-energy excitations such as phonons or mid-infrared plasmons. Here, we adapt a conventional instrument to probe energy loss down to 100 meV, and map phononic states in hexagonal boron nitride, a representative van der Waals material. The boron nitride spectra depend on the flake thickness and on the distance of the electron beam to the flake edges. To explain these observations, we developed a classical response theory that describes the interaction of fast electrons with (anisotropic) van der Waals slabs, revealing that the electron energy loss is dominated by excitation of hyperbolic phonon polaritons, and not of bulk phonons as often reported. Thus, our work is of fundamental importance for interpreting future low-energy loss spectra of van der Waals materials.Here the authors adapt a STEM-EELS system to probe energy loss down to 100 meV, and apply it to map phononic states in hexagonal boron nitride, revealing that the electron loss is dominated by hyperbolic phonon polaritons.

  16. van der Waals interactions between nanostructures: Some analytic results from series expansions

    NASA Astrophysics Data System (ADS)

    Stedman, T.; Drosdoff, D.; Woods, L. M.

    2014-01-01

    The van der Waals force between objects of nontrivial geometries is considered. A technique based on a perturbation series approach is formulated in the dilute limit. We show that the dielectric response and object size can be decoupled and dominant contributions in terms of object separations can be obtained. This is a powerful method, which enables straightforward calculations of the interaction for different geometries. Our results for planar structures, such as thin sheets, infinitely long ribbons, and ribbons with finite dimensions, may be applicable for nanostructured devices where the van der Waals interaction plays an important role.

  17. Photovoltaic Effect in an Electrically Tunable van der Waals Heterojunction

    PubMed Central

    2014-01-01

    Semiconductor heterostructures form the cornerstone of many electronic and optoelectronic devices and are traditionally fabricated using epitaxial growth techniques. More recently, heterostructures have also been obtained by vertical stacking of two-dimensional crystals, such as graphene and related two-dimensional materials. These layered designer materials are held together by van der Waals forces and contain atomically sharp interfaces. Here, we report on a type-II van der Waals heterojunction made of molybdenum disulfide and tungsten diselenide monolayers. The junction is electrically tunable, and under appropriate gate bias an atomically thin diode is realized. Upon optical illumination, charge transfer occurs across the planar interface and the device exhibits a photovoltaic effect. Advances in large-scale production of two-dimensional crystals could thus lead to a new photovoltaic solar technology. PMID:25057817

  18. Emergence of vancomycin resistance in the genus Streptococcus: characterization of a vanB transferable determinant in Streptococcus bovis.

    PubMed Central

    Poyart, C; Pierre, C; Quesne, G; Pron, B; Berche, P; Trieu-Cuot, P

    1997-01-01

    Streptococcus bovis NEM760 was isolated from a stool swab collected on admission from a patient as surveillance for vancomycin-resistant enterococci. Strain NEM760 was identified as S. bovis by conventional biochemical methods and partial sequence analysis of its 16S rRNA. This strain was resistant to a low level of vancomycin (MIC, 64 micrograms/ml) but was susceptible to teicoplanin (MIC, 1 micrograms/ml), and vancomycin induced resistance to both glycopeptides. The presence of a vanB-related gene in NEM760 was demonstrated in a PCR assay which enabled specific amplification of a 635-hp internal segment of vanB. Sequence analysis of the corresponding PCR product revealed that it was highly homologous (96% identity) to the prototype vanB sequence of Enterococcus faecalis V583. The VanB resistance of determinant of S. bovis NEM760 was transferred by conjugation to E. faecalis and Enterococcus faecium at a similar frequency of 2 x 10(-5) per donor. SmaI-digested genomic DNAs of independently obtained transconjugants of E. faecalis and E. faecium were analyzed by pulsed-field gel electrophoresis and Southern hybridization with a vanB DNA probe. The electrophoretic and hybridization patterns obtained with all transconjugants of the same species were indistinguishable and revealed vanB-containing chromosomal insertions of approximately 100 kb. These results suggest that the genes mediating VanB-type resistance in S. bovis NEM760 are part of large transferable genetic elements. The results presented in the report demonstrate for the first time the role of streptococci in the dissemination of vancomycin resistance among gram-positive bacteria. PMID:8980749

  19. Light scattering, aerosols, clouds, climate, Hendrik van de Hulst, and I

    NASA Astrophysics Data System (ADS)

    Chylek, Petr

    2018-02-01

    It is not often that I have the opportunity to write something that is not a scientific paper, and I am thankful for this opportunity to express my thoughts with regard to pursuits that are greater than those of science. In this van de Hulst essay, to honor Hendrik van de Hulst, I briefly summarize a few points from Hendrik's life that I find especially interesting, including his interests in spiritual (or religious) aspects of life, and his decision to avoid involvement in nucleation problems, a critical and basic uncertainty of current climate models. After that, I present briefly a few episodes from my own experiences as an apprentice of science and life.

  20. The nonlinear effect of resistive inhomogeneities on van der Pauw measurements

    NASA Astrophysics Data System (ADS)

    Koon, Daniel W.

    2005-03-01

    The resistive weighting function [D. W. Koon and C. J. Knickerbocker, Rev. Sci. Instrum. 63, 207 (1992)] quantifies the effect of small local inhomogeneities on van der Pauw resistivity measurements, but assumes such effects to be linear. This talk will describe deviations from linearity for a square van der Pauw geometry, modeled using a 5 x 5 grid network of discrete resistors and introducing both positive and negative perturbations to local resistors, covering nearly two orders of magnitude in -δρ/ρ or -δσ/σ. While there is a relatively modest quadratic nonlinearity for inhomogeneities of decreasing conductivity, the nonlinear term for inhomogeneities of decreasing resistivity is approximately cubic and can exceed the linear term.

  1. A Polarimetric Extension of the van Cittert-Zernike Theorem for Use with Microwave Interferometers

    NASA Technical Reports Server (NTRS)

    Piepmeier, J. R.; Simon, N. K.

    2004-01-01

    The van Cittert-Zernike theorem describes the Fourier-transform relationship between an extended source and its visibility function. Developments in classical optics texts use scalar field formulations for the theorem. Here, we develop a polarimetric extension to the van Cittert-Zernike theorem with applications to passive microwave Earth remote sensing. The development provides insight into the mechanics of two-dimensional interferometric imaging, particularly the effects of polarization basis differences between the scene and the observer.

  2. Li intercalation in graphite: A van der Waals density-functional study

    NASA Astrophysics Data System (ADS)

    Hazrati, E.; de Wijs, G. A.; Brocks, G.

    2014-10-01

    Modeling layered intercalation compounds from first principles poses a problem, as many of their properties are determined by a subtle balance between van der Waals interactions and chemical or Madelung terms, and a good description of van der Waals interactions is often lacking. Using van der Waals density functionals we study the structures, phonons and energetics of the archetype layered intercalation compound Li-graphite. Intercalation of Li in graphite leads to stable systems with calculated intercalation energies of -0.2 to -0.3 eV/Li atom, (referred to bulk graphite and Li metal). The fully loaded stage 1 and stage 2 compounds LiC6 and Li1 /2C6 are stable, corresponding to two-dimensional √{3 }×√{3 } lattices of Li atoms intercalated between two graphene planes. Stage N >2 structures are unstable compared to dilute stage 2 compounds with the same concentration. At elevated temperatures dilute stage 2 compounds easily become disordered, but the structure of Li3 /16C6 is relatively stable, corresponding to a √{7 }×√{7 } in-plane packing of Li atoms. First-principles calculations, along with a Bethe-Peierls model of finite temperature effects, allow for a microscopic description of the observed voltage profiles.

  3. van der Waals torque and force between dielectrically anisotropic layered media.

    PubMed

    Lu, Bing-Sui; Podgornik, Rudolf

    2016-07-28

    We analyse van der Waals interactions between a pair of dielectrically anisotropic plane-layered media interacting across a dielectrically isotropic solvent medium. We develop a general formalism based on transfer matrices to investigate the van der Waals torque and force in the limit of weak birefringence and dielectric matching between the ordinary axes of the anisotropic layers and the solvent. We apply this formalism to study the following systems: (i) a pair of single anisotropic layers, (ii) a single anisotropic layer interacting with a multilayered slab consisting of alternating anisotropic and isotropic layers, and (iii) a pair of multilayered slabs each consisting of alternating anisotropic and isotropic layers, looking at the cases where the optic axes lie parallel and/or perpendicular to the plane of the layers. For the first case, the optic axes of the oppositely facing anisotropic layers of the two interacting slabs generally possess an angular mismatch, and within each multilayered slab the optic axes may either be the same or undergo constant angular increments across the anisotropic layers. In particular, we examine how the behaviors of the van der Waals torque and force can be "tuned" by adjusting the layer thicknesses, the relative angular increment within each slab, and the angular mismatch between the slabs.

  4. 8. Historic American Buildings Survey Cortlandt Van Dyke Hubbard, Photographer ...

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

    8. Historic American Buildings Survey Cortlandt Van Dyke Hubbard, Photographer October 1959 BRICK NOGGING AND ORIGINAL WEATHERBOARDING OF SOUTH ELEVATION - White Meadow Farm, State Roads 290 & 262 (moved to Lewes, DE), Cool Spring, Sussex County, DE

  5. Accurate van der Waals coefficients from density functional theory

    PubMed Central

    Tao, Jianmin; Perdew, John P.; Ruzsinszky, Adrienn

    2012-01-01

    The van der Waals interaction is a weak, long-range correlation, arising from quantum electronic charge fluctuations. This interaction affects many properties of materials. A simple and yet accurate estimate of this effect will facilitate computer simulation of complex molecular materials and drug design. Here we develop a fast approach for accurate evaluation of dynamic multipole polarizabilities and van der Waals (vdW) coefficients of all orders from the electron density and static multipole polarizabilities of each atom or other spherical object, without empirical fitting. Our dynamic polarizabilities (dipole, quadrupole, octupole, etc.) are exact in the zero- and high-frequency limits, and exact at all frequencies for a metallic sphere of uniform density. Our theory predicts dynamic multipole polarizabilities in excellent agreement with more expensive many-body methods, and yields therefrom vdW coefficients C6, C8, C10 for atom pairs with a mean absolute relative error of only 3%. PMID:22205765

  6. Franckeite as a naturally occurring van der Waals heterostructure

    PubMed Central

    Molina-Mendoza, Aday J.; Giovanelli, Emerson; Paz, Wendel S.; Niño, Miguel Angel; Island, Joshua O.; Evangeli, Charalambos; Aballe, Lucía; Foerster, Michael; van der Zant, Herre S. J.; Rubio-Bollinger, Gabino; Agraït, Nicolás; Palacios, J. J.; Pérez, Emilio M.; Castellanos-Gomez, Andres

    2017-01-01

    The fabrication of van der Waals heterostructures, artificial materials assembled by individual stacking of 2D layers, is among the most promising directions in 2D materials research. Until now, the most widespread approach to stack 2D layers relies on deterministic placement methods, which are cumbersome and tend to suffer from poor control over the lattice orientations and the presence of unwanted interlayer adsorbates. Here, we present a different approach to fabricate ultrathin heterostructures by exfoliation of bulk franckeite which is a naturally occurring and air stable van der Waals heterostructure (composed of alternating SnS2-like and PbS-like layers stacked on top of each other). Presenting both an attractive narrow bandgap (<0.7 eV) and p-type doping, we find that the material can be exfoliated both mechanically and chemically down to few-layer thicknesses. We present extensive theoretical and experimental characterizations of the material's electronic properties and crystal structure, and explore applications for near-infrared photodetectors. PMID:28194037

  7. Cross-scale observations of the 2015 St. Patrick's day storm: THEMIS, Van Allen Probes, and TWINS

    DOE PAGES

    Goldstein, J.; Angelopoulos, V.; De Pascuale, S.; ...

    2016-12-10

    In this paper, we present cross-scale magnetospheric observations of the 17 March 2015 (St. Patrick's Day) storm, by Time History of Events and Macroscale Interactions during Substorms (THEMIS), Van Allen Probes (Radiation Belt Storm Probes), and Two Wide-angle Imaging Neutral-atom Spectrometers (TWINS), plus upstream ACE/Wind solar wind data. THEMIS crossed the bow shock or magnetopause 22 times and observed the magnetospheric compression that initiated the storm. Empirical models reproduce these boundary locations within 0.7 R E. Van Allen Probes crossed the plasmapause 13 times; test particle simulations reproduce these encounters within 0.5 R E. Before the storm, Van Allen Probesmore » measured quiet double-nose proton spectra in the region of corotating cold plasma. About 15 min after a 0605 UT dayside southward turning, Van Allen Probes captured the onset of inner magnetospheric convection, as a density decrease at the moving corotation-convection boundary (CCB) and a steep increase in ring current (RC) proton flux. During the first several hours of the storm, Van Allen Probes measured highly dynamic ion signatures (numerous injections and multiple spectral peaks). Sustained convection after ~1200 UT initiated a major buildup of the midnight-sector ring current (measured by RBSP A), with much weaker duskside fluxes (measured by RBSP B, THEMIS a and THEMIS d). A close conjunction of THEMIS d, RBSP A, and TWINS 1 at 1631 UT shows good three-way agreement in the shapes of two-peak spectra from the center of the partial RC. A midstorm injection, observed by Van Allen Probes and TWINS at 1740 UT, brought in fresh ions with lower average energies (leading to globally less energetic spectra in precipitating ions) but increased the total pressure. Finally, the cross-scale measurements of 17 March 2015 contain significant spatial, spectral, and temporal structure.« less

  8. Understanding the nanoscale local buckling behavior of vertically aligned MWCNT arrays with van der Waals interactions

    NASA Astrophysics Data System (ADS)

    Li, Yupeng; Kim, Hyung-Ick; Wei, Bingqing; Kang, Junmo; Choi, Jae-Boong; Nam, Jae-Do; Suhr, Jonghwan

    2015-08-01

    The local buckling behavior of vertically aligned carbon nanotubes (VACNTs) has been investigated and interpreted in the view of a collective nanotube response by taking van der Waals interactions into account. To the best of our knowledge, this is the first report on the case of collective VACNT behavior regarding van der Waals force among nanotubes as a lateral support effect during the buckling process. The local buckling propagation and development of VACNTs were experimentally observed and theoretically analyzed by employing finite element modeling with lateral support from van der Waals interactions among nanotubes. Both experimental and theoretical analyses show that VACNTs buckled in the bottom region with many short waves and almost identical wavelengths, indicating a high mode buckling. Furthermore, the propagation and development mechanism of buckling waves follow the wave damping effect.The local buckling behavior of vertically aligned carbon nanotubes (VACNTs) has been investigated and interpreted in the view of a collective nanotube response by taking van der Waals interactions into account. To the best of our knowledge, this is the first report on the case of collective VACNT behavior regarding van der Waals force among nanotubes as a lateral support effect during the buckling process. The local buckling propagation and development of VACNTs were experimentally observed and theoretically analyzed by employing finite element modeling with lateral support from van der Waals interactions among nanotubes. Both experimental and theoretical analyses show that VACNTs buckled in the bottom region with many short waves and almost identical wavelengths, indicating a high mode buckling. Furthermore, the propagation and development mechanism of buckling waves follow the wave damping effect. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr03581c

  9. Generation of EMIC Waves Observed by Van Allen Probes at Low L-shells of Earth's Magnetosphere

    NASA Astrophysics Data System (ADS)

    Gamayunov, K. V.; Zhang, J.; Saikin, A.; Rassoul, H.

    2017-12-01

    In a multi-ion magnetospheric plasma, where the major species are H+, He+, and O+, the He-band of electromagnetic ion cyclotron (EMIC) waves is the dominant band observed in the inner magnetosphere, and waves are generally quasi-field-aligned inside the geostationary orbit. Almost all the satellite-based studies of EMIC waves before Van Allen Probes, however, have not reported waves below L 3.5. There is probably only one exception from the Akebono satellite where both the H-band and He-band EMIC waves were observed at L 2. The situation has changed dramatically after two Van Allen Probes spacecraft were launched on 30 August, 2012, and many EMIC wave events have been observed below L=4. The Van Allen Probes observations confirm that the He-band of EMIC waves is a dominant band in the inner magnetosphere, but the observation of the He-band waves below L=4 is a new and quite unexpected result compared to our knowledge about EMIC waves before the Van Allen Probes era. In addition, observations show that almost all the He-band EMIC waves are linearly polarized in the region L < 4. This result is also new and unexpected. Here we will present an observational test of the generation mechanism for the He-band EMIC waves observed by Van Allen Probes at L 2.8 on 18 March, 2013. All the plasma parameters, DC magnetic field, and energetic ion distribution functions will be taken from the Van Allen Probes observations during the EMIC wave event to calculate growth rates of EMIC waves. We will then identify the energetic ions responsible for instability, frequencies and normals generated, and physical mechanism of instability.

  10. Cross-scale observations of the 2015 St. Patrick's day storm: THEMIS, Van Allen Probes, and TWINS

    SciTech Connect

    Goldstein, J.; Angelopoulos, V.; De Pascuale, S.

    In this paper, we present cross-scale magnetospheric observations of the 17 March 2015 (St. Patrick's Day) storm, by Time History of Events and Macroscale Interactions during Substorms (THEMIS), Van Allen Probes (Radiation Belt Storm Probes), and Two Wide-angle Imaging Neutral-atom Spectrometers (TWINS), plus upstream ACE/Wind solar wind data. THEMIS crossed the bow shock or magnetopause 22 times and observed the magnetospheric compression that initiated the storm. Empirical models reproduce these boundary locations within 0.7 R E. Van Allen Probes crossed the plasmapause 13 times; test particle simulations reproduce these encounters within 0.5 R E. Before the storm, Van Allen Probesmore » measured quiet double-nose proton spectra in the region of corotating cold plasma. About 15 min after a 0605 UT dayside southward turning, Van Allen Probes captured the onset of inner magnetospheric convection, as a density decrease at the moving corotation-convection boundary (CCB) and a steep increase in ring current (RC) proton flux. During the first several hours of the storm, Van Allen Probes measured highly dynamic ion signatures (numerous injections and multiple spectral peaks). Sustained convection after ~1200 UT initiated a major buildup of the midnight-sector ring current (measured by RBSP A), with much weaker duskside fluxes (measured by RBSP B, THEMIS a and THEMIS d). A close conjunction of THEMIS d, RBSP A, and TWINS 1 at 1631 UT shows good three-way agreement in the shapes of two-peak spectra from the center of the partial RC. A midstorm injection, observed by Van Allen Probes and TWINS at 1740 UT, brought in fresh ions with lower average energies (leading to globally less energetic spectra in precipitating ions) but increased the total pressure. Finally, the cross-scale measurements of 17 March 2015 contain significant spatial, spectral, and temporal structure.« less

  11. Top-Level Players' Visual Control of Interceptive Actions: Bootsma and Van Wieringen (1990) 20 Years Later

    ERIC Educational Resources Information Center

    Bootsma, Reinoud J.; Fernandez, Laure; Morice, Antoine H. P.; Montagne, Gilles

    2010-01-01

    Using a two-step approach, Van Soest et al. (2010) recently questioned the pertinence of the conclusions drawn by Bootsma and Van Wieringen (1990) with respect to the visual regulation of an exemplary rapid interceptive action: the attacking forehand drive in table tennis. In the first step, they experimentally compared the movement behaviors of…

  12. The Effect of Designed Geometry Teaching Lesson to the Candidate Teachers' Van Hiele Geometric Thinking Level

    ERIC Educational Resources Information Center

    Yilmaz, Gül Kaleli; Koparan, Timur

    2016-01-01

    The aim of this study is to find out how designed Geometry Teaching Lesson affects candidate teachers' Van Hiele Geometric Thinking Levels. For that purpose, 14 weeks long study was performed with 44 candidate teachers who were university students in Turkey. Van Hiele Geometric Thinking Test was applied to candidate teachers before and after…

  13. Community Music during the New Deal: The Contributions of Willem Van de Wall and Max Kaplan

    ERIC Educational Resources Information Center

    Krikun, Andrew

    2010-01-01

    Willem Van de Wall (1887-1953) and Max Kaplan (1911-98) built careers spanning music performance, music education, adult education, sociology, social work, music therapy and community music. Willem Van de Wall was a seminal influence on the development of the fields of music therapy and adult education--researching the role of music in…

  14. Determination of radiocarbon reservoir age of Lake Van by mineral magnetic and geochemical analysis

    NASA Astrophysics Data System (ADS)

    Makaroglu, Ozlem; Namik Cagatay, M.; Pesonen, Lauri J.; Orbay, Naci

    2017-04-01

    Lake Van is the largest soda lake in the world, located on the east Anatolian Plateau in Turkey. Its varved sediments provide an excellent archive of high-resolution paleoclimate record for the Near East. Varve counting and radiocarbon methods are therefore important dating techniques for investigating the Lake Van sedimentary paleoclimate record. In here we present detailed magnetic and geochemical record of Lake Van. We have studied 4.56 m (core VP0801) and 4.70 m (core VP0807) long cores recovered from 80 m and 65 m water depths located in SE and SW of Lake Van, respectively. Here, we have benefited from magnetic properties with associated remanent magnetization of the sediments from Lake Van to correlate the cores which contain of tephra layers. The cores cover the last 8.4 ka and lithologically include three laminated sedimentary units. From top to the bottom, the units were dated 4.2 ka BP-present, 5.4-4.2 ka BP and older than 5.4 ka BP. We identified tephra layers previously dated by varve counting, and used the varve ages to obtain age models for the cores. We also obtained a total of eight Accelerator Mass Spectrometry (AMS) 14C dates from total organic carbon (TOC) in the two cores, close to the tephra layers. Comparison of the varve ages of the AMS 14C dated samples with their corresponding AMS 14C dates indicates large differences, suggesting significant reservoir ages that range from 2.8 to 2.5 ka for 3.0-2.4 varve ka BP and from 2.8 to 3.3 ka for 8.0-5.9 varve ka BP. The results suggest that the reservoir age of the organic matter increases with the varve age of the sediments. This increase is mainly related to the rate of supply of "dead" carbon from the old carbonate rocks in the watershed of Lake Van, which was relatively higher during 8.4-5.9 ka than during 3.0-2.4 ka BP because of the higher atmospheric precipitation and higher rate of biochemical weathering during the former period.

  15. Spectral asymmetry of atoms in the van der Waals potential of an optical nanofiber

    NASA Astrophysics Data System (ADS)

    Patterson, B. D.; Solano, P.; Julienne, P. S.; Orozco, L. A.; Rolston, S. L.

    2018-03-01

    We measure the modification of the transmission spectra of cold 87Rb atoms in the proximity of an optical nanofiber (ONF). Van der Waals interactions between the atoms an the ONF surface decrease the resonance frequency of atoms closer to the surface. An asymmetric spectra of the atoms holds information of their spatial distribution around the ONF. We use a far-detuned laser beam coupled to the ONF to thermally excite atoms at the ONF surface. We study the change of transmission spectrum of these atoms as a function of heating laser power. A semiclassical phenomenological model for the thermal excitation of atoms in the atom-surface van der Waals bound states is in good agreement with the measurements. This result suggests that van der Waals potentials could be used to trap and probe atoms at few nanometers from a dielectric surface, a key tool for hybrid photonic-atomic quantum systems.

  16. The "Discernment of a Human Face" in Research: A Reaction to Van Hesteren's Human Science and Counselling.

    ERIC Educational Resources Information Center

    Knowles, Don

    1986-01-01

    Responds to Van Hesteren's advocacy of a "human science" orientation, using constructs and analytical methods from phenomenology to enhance methodology. Approves of a philosophy of science and of a self-perspective. Questions the need for complex terminology, Van Hesteren's definition of what constitutes research, quantification, and…

  17. A review on data and predictions of water dielectric spectra for calculations of van der Waals surface forces.

    PubMed

    Wang, Jianlong; Nguyen, Anh V

    2017-12-01

    Van der Waals forces are one of the important components of intermolecular, colloidal and surface forces governing many phenomena and processes. The latest examples include the colloidal interactions between hydrophobic colloids and interfaces in ambient (non-degassed) water in which dissolved gases and nanobubbles are shown to affect the van der Waals attractions significantly. The advanced computation of van der Waals forces in aqueous systems by the Lifshitz theory requires reliable data for water dielectric spectra. In this paper we review the available predictions of water dielectric spectra for calculating colloidal and surface van der Waals forces. Specifically, the available experimental data for the real and imaginary parts of the complex dielectric function of liquid water in the microwave, IR and UV regions and various corresponding predictions of the water spectra are critically reviewed. The data in the UV region are critical, but the available predictions are still based on the outdated data obtained in 1974 (for frequency only up to 25.5eV). We also reviewed and analysed the experimental data obtained for the UV region in 2000 (for frequency up to 50eV) and 2015 (for frequency up to 100eV). The 1974 and 2000 data require extrapolations to higher frequencies needed for calculating the van der Waals forces but remain inaccurate. Our analysis shows that the latest data of 2015 do not require the extrapolation and can be used to reliably calculate van der Waals forces. The most recent water dielectric spectra gives the (non-retarded) Hamaker constant, A=5.20×10 -20 J, for foam films of liquid water. This review provides the most updated and reliable water dielectric spectra to compute van der Waals forces in aqueous systems. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Martin Van Butchell (1735-1814): the eccentric, "kook" dentist of old London.

    PubMed

    Christen, A G; Christen, J A

    1999-11-01

    This article is a thumbnail sketch of the life and times of Martin Van Butchell (1735-1814), an eccentric, "kook" advertising dentist of Old London. Van Butchell earned these descriptive labels by displaying an unorthodox lifestyle, an outrageous personal appearance and outlandish, extreme and socially unacceptable personal and professional behaviors. While the general populace seemed to be fascinated by his strange ways, dentists and physicians were generally alienated by them. Nevertheless, he was considered a good dentist for his time, and he was extremely popular with his patients. Martin practiced dentistry for 23 years, and he practiced medicine as well, specializing in the treatment of ruptures and anal fistulas. Van Butchell interacted greatly with both John and William Hunter, who became two of the most famous and talented physicians, surgeons, anatomists and biologists of all time. When his first wife, Mary died, Martin arranged for her body to be embalmed and publicly displayed in his dental office for advertising purposes. Her preserved body was shown at the Museum of the Royal College of Surgeons (London), until it was destroyed by a German fire bomb in May, 1941. Mary's remains were on public display for a total of 166 years.

  19. Spacecraft surface charging within geosynchronous orbit observed by the Van Allen Probes

    DOE PAGES

    Sarno-Smith, Lois K.; Larsen, Brian A.; Skoug, Ruth M.; ...

    2016-02-27

    Using the Helium Oxygen Proton Electron (HOPE) and Electric Field and Waves (EFW) instruments from the Van Allen Probes, we explored the relationship between electron energy fluxes in the eV and keV ranges and spacecraft surface charging. We present statistical results on spacecraft charging within geosynchronous orbit by L and MLT. An algorithm to extract the H+ charging line in the HOPE instrument data was developed to better explore intense charging events. Also, this study explored how spacecraft potential relates to electron number density, electron pressure, electron temperature, thermal electron current, and low-energy ion density between 1 and 210 eV.more » It is demonstrated that it is imperative to use both EFW potential measurements and the HOPE instrument ion charging line for examining times of extreme spacecraft charging of the Van Allen Probes. The results of this study show that elevated electron energy fluxes and high-electron pressures are present during times of spacecraft charging but these same conditions may also occur during noncharging times. Furthermore, we also show noneclipse significant negative charging events on the Van Allen Probes.« less

  20. Spectral Properties of Dirac Billiards at the van Hove Singularities.

    PubMed

    Dietz, B; Klaus, T; Miski-Oglu, M; Richter, A; Wunderle, M; Bouazza, C

    2016-01-15

    We study distributions of the ratios of level spacings of rectangular and Africa-shaped superconducting microwave resonators containing circular scatterers on a triangular grid, so-called Dirac billiards (DBs). The high-precision measurements allowed the determination of, respectively, all 1651 and 1823 eigenfrequencies in the first two bands. The resonance densities are similar to that of graphene. They exhibit two sharp peaks at the van Hove singularities which separate the band structure into regions with a linear and a quadratic dispersion relation, respectively. In the vicinity of the van Hove singularities we observe rapid changes in, e.g., the wave function structure. Accordingly, we question whether the spectral properties are there still determined by the shapes of the DBs. The commonly used statistical measures are no longer applicable; however, we demonstrate in this Letter that the ratio distributions provide suitable measures.

  1. Astronaut James D. van Hoften examines student experiment on Challenger

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Astronaut James D. van Hoften, 41-C mission specialist, holds an aluminum box full of honeybees. The experiment in earth orbit is duplicated with another colony of the bees on earth. This is an experiment submitted by student researchers.

  2. An Empirical Introduction to the Concept of Chemical Element Based on Van Hiele's Theory of Level Transitions

    ERIC Educational Resources Information Center

    Vogelezang, Michiel; Van Berkel, Berry; Verdonk, Adri

    2015-01-01

    Between 1970 and 1990, the Dutch working group "Empirical Introduction to Chemistry" developed a secondary school chemistry education curriculum based on the educational vision of the mathematicians van Hiele and van Hiele-Geldof. This approach viewed learning as a process in which students must go through discontinuous level transitions…

  3. View west along Lower Raceway, Van Houten Street, with (left ...

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

    View west along Lower Raceway, Van Houten Street, with (left to right) Congdon Mill, Phoenix Mill, and Fabricolor Mill (a.k.a., Industry Mill, HAER No. NJ-15) - Great Falls/S. U. M. Power Canal System, Paterson, Passaic County, NJ

  4. The effects of van der Waals attractions on cloud droplet growth by coalescence

    NASA Technical Reports Server (NTRS)

    Rogers, Jan R.; Davis, Robert H.

    1990-01-01

    The inclusion of van der Waals attractions in the interaction between cloud droplets has been recently shown to significantly increase the collision efficiencies of the smaller droplets. In the current work, these larger values for the collision efficiencies are used in a population dynamics model of the droplet size distribution evolution with time, in hopes of at least partially resolving the long-standing paradox in cloud microphysics that predicted rates of the onset of precipitation are generally much lower than those which are observed. Evolutions of several initial cloud droplet spectra have been tracked in time. Size evolutions are compared as predicted from the use of collision efficiencies computed using two different models to allow for droplet-droplet contact: one which considers slip flow effects only, and one which considers the combined effects of van der Waals forces and slip flow. The rate at which the droplet mass density function shifts to larger droplet sizes is increased by typically 20-25 percent, when collision efficiencies which include van der Waals forces are used.

  5. Communicating the promise, risks, and ethics of large-scale, open space microbiome and metagenome research.

    PubMed

    Shamarina, Daria; Stoyantcheva, Iana; Mason, Christopher E; Bibby, Kyle; Elhaik, Eran

    2017-10-04

    The public commonly associates microorganisms with pathogens. This suspicion of microorganisms is understandable, as historically microorganisms have killed more humans than any other agent while remaining largely unknown until the late seventeenth century with the works of van Leeuwenhoek and Kircher. Despite our improved understanding regarding microorganisms, the general public are apt to think of diseases rather than of the majority of harmless or beneficial species that inhabit our bodies and the built and natural environment. As long as microbiome research was confined to labs, the public's exposure to microbiology was limited. The recent launch of global microbiome surveys, such as the Earth Microbiome Project and MetaSUB (Metagenomics and Metadesign of Subways and Urban Biomes) project, has raised ethical, financial, feasibility, and sustainability concerns as to the public's level of understanding and potential reaction to the findings, which, done improperly, risk negative implications for ongoing and future investigations, but done correctly, can facilitate a new vision of "smart cities." To facilitate improved future research, we describe here the major concerns that our discussions with ethics committees, community leaders, and government officials have raised, and we expound on how to address them. We further discuss ethical considerations of microbiome surveys and provide practical recommendations for public engagement.

  6. Teaching microbiology to undergraduate students in the humanities and the social sciences.

    PubMed

    Oren, Aharon

    2015-10-01

    This paper summarizes my experiences teaching a 28-hour course on the bacterial world for undergraduate students in the humanities and the social sciences at the Hebrew University of Jerusalem. This course was offered in the framework of a program in which students must obtain credit points for courses offered by other faculties to broaden their education. Most students had little biology in high school and had never been exposed to the basics of chemistry. Using a historical approach, highlighting the work of pioneers such as van Leeuwenhoek, Koch, Fleming, Pasteur, Winogradsky and Woese, I covered a broad area of general, medical, environmental and evolutionary microbiology. The lectures included basic concepts of organic and inorganic chemistry necessary to understand the principles of fermentations and chemoautotrophy, and basic molecular biology to explain biotechnology using transgenic microorganisms and molecular phylogeny. Teaching the basics of microbiology to intelligent students lacking any background in the natural sciences was a rewarding experience. Some students complained that, in spite of my efforts, basic concepts of chemistry remained beyond their understanding. But overall the students' evaluation showed that the course had achieved its goal. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  7. Detection of biological threats. A challenge for directed molecular evolution.

    PubMed

    Petrenko, Valery A; Sorokulova, Iryna B

    2004-08-01

    The probe technique originated from early attempts of Anton van Leeuwenhoek to contrast microorganisms under the microscope using plant juices, successful staining of tubercle bacilli with synthetic dyes by Paul Ehrlich and discovery of a stain for differentiation of gram-positive and gram-negative bacteria by Hans Christian Gram. The technique relies on the principle that pathogens have unique structural features, which can be recognized by specifically labeled organic molecules. A hundred years of extensive screening efforts led to discovery of a limited assortment of organic probes that are used for identification and differentiation of bacteria. A new challenge--continuous monitoring of biological threats--requires long lasting molecular probes capable of tight specific binding of pathogens in unfavorable conditions. To respond to the challenge, probe technology is being revolutionized by utilizing methods of combinatorial chemistry, phage display and directed molecular evolution. This review describes how molecular evolution methods are applied for development of peptide, antibody and phage probes, and summarizes the author's own data on development of landscape phage probes against Salmonella typhimurium. The performance of the probes in detection of Salmonella is illustrated by a precipitation test, enzyme-linked immunosorbent assay (ELISA), fluorescence-activated cell sorting (FACS) and fluorescent, optical and electron microscopy.

  8. Geautomatiseerde Verwerking van Militaire berichten Volgens ADatP-3 (Automated Processing of Military Messages According to ADatP-3)

    DTIC Science & Technology

    1992-06-01

    ATCCIS beoogt juist dat te bereiken door te werken aan ecn informatie model en een data element dictionary. TNO-rapport Pagina 9 Binnen bet C2...en distributie 44 4.3.2 Interface met de gebruiker 45 4.3.3 Interface met dc operationcle database 46 TNO-rapport Pagina 11 4.3.3.1 Interpretatie...die bezig zijn met het ontwikkelen en implementeren van berichtformaten. Deel I van de publicatie bevat de beschrijving van FORMETS, delen 11 , I11 en

  9. [Education in anatomy initiated by Pompe van Meerdervoort].

    PubMed

    Koji, Takehiko; Aikawa, Tadaomi

    2008-12-01

    Pompe van Meerdervoort arrived at Nagasaki port on September 21, 1857 and started his western-style medical education for the first time in the Nishiyakusho of Nagasaki on November 12, 1857. He had 12 students including Ryojun Matsumono. The curriculum was largely based on that of Utrecht Army Medical School, which was re-organized after 1841 and very good in balance of theory and practice. Among subjects, much attention was paid for Anatomy which was quite advancing at the time and in fact the lecture was given on every Tuesday, Thursday and Saturday morning from 1857 to the end of 1859. His lecture note on Anatomy was based on Handboek der Ontleedkunde van den Mensch originally written by C. E. Bock, which was translated into Dutch by P. H. Pool. The note currently available is a copy by the students. In Europe of those days, microscopes were developed and "Histology" had been established as a new science. Therefore, his lecture contained details of histological findings and now we can appreciate his policy to think much of Anatomy in the introduction of western-style medical education.

  10. [Trait-aggression and suicide of Vincent van Gogh].

    PubMed

    Pezenhoffer, Ibolya; Gerevich, József

    2015-01-01

    Although in recent decades the literature has paid special attention to Vincent van Gogh's life, work and illness, there has still not been an examination of the connections between his trait aggression and his suicide. The present study traces, in the light of this trait aggression, the predictive factors that can be observed on the path leading to the artist's suicide. Biographical documents, case history data, as well as letters and the findings of earlier research have been used in the course of the analysis. Among the distal suicide risk factors we find a positive family anamnesis, childhood traumas (emotional deprivation, identity problems associated with the name Vincent), a vagrant, homeless way of life, failures in relationships with women, and psychotic episodes appearing in rushes. The proximal factors include the tragic friendship with Gauguin (frustrated love), his brother Theo's marriage (experienced as a loss), and a tendency to self-destruction. Both factor groups on the one hand determined the course of development of the trait aggression and on the other can also be regarded as a manifestation of that trait aggression. It can be said that the trait aggression played an important role in Van Gogh's suicide.

  11. Assessment of narrow angles by gonioscopy, Van Herick method and anterior segment optical coherence tomography.

    PubMed

    Park, Seong Bae; Sung, Kyung Rim; Kang, Sung Yung; Jo, Jung Woo; Lee, Kyoung Sub; Kook, Michael S

    2011-07-01

    To evaluate anterior chamber (AC) angles using gonioscopy, Van Herick technique and anterior segment optical coherence tomography (AS-OCT). One hundred forty-eight consecutive subjects were enrolled. The agreement between any two of three diagnostic methods, gonioscopy, AS-OCT and Van Herick, was calculated in narrow-angle patients. The area under receiver-operating characteristic curves (AUC) for discriminating between narrow and open angles determined by gonioscopy was calculated in all participants for AS-OCT parameter angle opening distance (AOD), angle recess area, trabecular iris surface area and anterior chamber depth (ACD). As a subgroup analysis, capability of AS-OCT parameters for detecting angle closure defined by AS-OCT was assessed in narrow-angle patients. The agreement between the Van Herick method and gonioscopy in detecting angle closure was excellent in narrow angles (κ = 0.80, temporal; κ = 0.82, nasal). However, agreement between gonioscopy and AS-OCT and between the Van Herick method and AS-OCT was poor (κ = 0.11-0.16). Discrimination capability of AS-OCT parameters between open and narrow angles determined by gonioscopy was excellent for all AS-OCT parameters (AUC, temporal: AOD500 = 0.96, nasal: AOD500 = 0.99). The AUCs for detecting angle closure defined by AS-OCT image in narrow angle subjects was good for all AS-OCT parameters (AUC, 0.80-0.94) except for ACD (temporal: ACD = 0.70, nasal: ACD = 0.63). Assessment of narrow angles by gonioscopy and the Van Herick technique showed good agreement, but both measurements revealed poor agreement with AS-OCT. The angle closure detection capability of AS-OCT parameters was excellent; however, it was slightly lower in ACD.

  12. Spatial and temporal characterization of relativistic electron enhancements during the Van Allen Probes era.

    NASA Astrophysics Data System (ADS)

    Pinto, V. A.; Sibeck, D. G.; Moya, P. S.; Lyons, L. R.; Kanekal, S. G.; Kletzing, C.

    2016-12-01

    During the Van Allen probes era from September 2012 to June 2016 we have identified 53 relativistic electron enhancement events determined by increases to 2x103 #/sr-1}s{-1}cm^{-2 and above in the >2 MeV electron fluxes at geostationary orbit as measured by the GOES 13 and 15 Energetic Particle Sensor (EPS) instrument. Using the Van Allen Probes ECT-REPT and GOES EPS instruments we have characterized the radial and temporal profiles of the events, grouping them according to how the increases propagate radially. Using OMNI data we have studied the statistical properties of the solar wind for each group of events and have classified similarities and differences that might be relevant for each enhancement profile. We have also studied temporal and spatial wave activity (ULF and EMIC waves) using GOES magnetometer data and Van Allen Probes EMFISIS data for the different groups of events and categorized the appearance of such waves for the different enhancement profiles.

  13. Uncovering Droop Control Laws Embedded Within the Nonlinear Dynamics of Van der Pol Oscillators

    SciTech Connect

    Sinha, Mohit; Dorfler, Florian; Johnson, Brian B.

    This paper examines the dynamics of power-electronic inverters in islanded microgrids that are controlled to emulate the dynamics of Van der Pol oscillators. The general strategy of controlling inverters to emulate the behavior of nonlinear oscillators presents a compelling time-domain alternative to ubiquitous droop control methods which presume the existence of a quasistationary sinusoidal steady state and operate on phasor quantities. We present two main results in this paper. First, by leveraging the method of periodic averaging, we demonstrate that droop laws are intrinsically embedded within a slower time scale in the nonlinear dynamics of Van der Pol oscillators. Second,more » we establish the global convergence of amplitude and phase dynamics in a resistive network interconnecting inverters controlled as Van der Pol oscillators. Furthermore, under a set of nonrestrictive decoupling approximations, we derive sufficient conditions for local exponential stability of desirable equilibria of the linearized amplitude and phase dynamics.« less

  14. Graphene Substrate for van der Waals Epitaxy of Layer-Structured Bismuth Antimony Telluride Thermoelectric Film.

    PubMed

    Kim, Eun Sung; Hwang, Jae-Yeol; Lee, Kyu Hyoung; Ohta, Hiromichi; Lee, Young Hee; Kim, Sung Wng

    2017-02-01

    Graphene as a substrate for the van der Waals epitaxy of 2D layered materials is utilized for the epitaxial growth of a layer-structured thermoelectric film. Van der Waals epitaxial Bi 0.5 Sb 1.5 Te 3 film on graphene synthesized via a simple and scalable fabrication method exhibits good crystallinity and high thermoelectric transport properties comparable to single crystals. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Aqueous gating of van der Waals materials on bilayer nanopaper.

    PubMed

    Bao, Wenzhong; Fang, Zhiqiang; Wan, Jiayu; Dai, Jiaqi; Zhu, Hongli; Han, Xiaogang; Yang, Xiaofeng; Preston, Colin; Hu, Liangbing

    2014-10-28

    In this work, we report transistors made of van der Waals materials on a mesoporous paper with a smooth nanoscale surface. The aqueous transistor has a novel planar structure with source, drain, and gate electrodes on the same surface of the paper, while the mesoporous paper is used as an electrolyte reservoir. These transistors are enabled by an all-cellulose paper with nanofibrillated cellulose (NFC) on the top surface that leads to an excellent surface smoothness, while the rest of the microsized cellulose fibers can absorb electrolyte effectively. Based on two-dimensional van der Waals materials, including MoS2 and graphene, we demonstrate high-performance transistors with a large on-off ratio and low subthreshold swing. Such planar transistors with absorbed electrolyte gating can be used as sensors integrated with other components to form paper microfluidic systems. This study is significant for future paper-based electronics and biosensors.

  16. Cosmology with an interacting van der Waals fluid

    NASA Astrophysics Data System (ADS)

    Elizalde, E.; Khurshudyan, M.

    A model for the late-time accelerated expansion of the Universe is considered where a van der Waals fluid interacting with matter plays the role of dark energy. The transition towards this phase in the cosmic evolution history is discussed in detail and, moreover, a complete classification of the future finite-time singularities is obtained for six different possible forms of the nongravitational interaction between dark energy (the van der Waals fluid) and dark matter. This study shows, in particular, that a Universe with a noninteracting three-parameter van der Waals fluid can evolve into a Universe characterized by a type IV (generalized sudden) singularity. On the other hand, for certain values of the parameters, exit from the accelerated expanding phase is possible in the near future, what means that the expansion of the Universe in the future could become decelerated - to our knowledge, this interesting situation is not commonplace in the literature. On the other hand, our study shows that space can be divided into different regions. For some of them, in particular, the nongravitational interactions Q = 3Hbρde, Q = 3Hbρdm and Q = 3Hb(ρde + ρde) may completely suppress future finite-time singularity formation, for sufficiently high values of b. On the other hand, for some other regions of the parameter space, the mentioned interactions would not affect the singularity type, namely the type IV singularity generated in the case of the noninteracting model would be preserved. A similar conclusion has been archived for the cases of Q = 3bHρdeρdm/(ρde + ρdm), Q = 3bHρdm2/(ρ de + ρdm) and Q = 3bHρde2/(ρ de + ρdm) nongravitational interactions, with only one difference: the Q = 3bHρdm2/(ρ de + ρdm) interaction will change the type IV singularity of the noninteracting model into a type II (the sudden) singularity.

  17. Van Swieten and the renaissance of the Vienna Medical School.

    PubMed

    Kidd, M; Modlin, I M

    2001-04-01

    The period until 1745 found the Viennese medical system languishing far behind advances made in other major European centers. This chaotic situation was reversed by the foresight and breadth of vision of the Empress Maria Theresa, who initiated considerable reform in Austria by actively recruiting the best minds of the time to reduce the intellectual and technologic differences. Her ability to entice one of Boerhaave's most eminent pupils, Gerard van Swieten, to leave Leiden for Vienna, particularly benefited the Vienna Medical School. In 1745 van Swieten assumed responsibility for reconfiguration of the patronage and nepotism-ridden medical system of the Austro-Hungarian Empire. As a first task, he swiftly expunged the influence of the Jesuits and other religious orders from medicine and established formal training and examinations, transforming the medical discipline into a meritocracy. Excelling as a physician and an innovative teacher, he also established a close personal relationship with the Empress and became her medical confidante. To a large part, the success of this first great Viennese medical school was owed to de Haen, who left Leiden to implement Boerhaave's method of clinical teaching. As a result of these innovations and with considerable support from the Empress, the University of Vienna, particularly its medical school, within a few decades achieved recognition throughout Europe as a seat of learning and scholarship. Van Swieten would not be remembered today if his contribution had been only scholarly or scientific achievements. He propelled Austrian medicine to a level commensurate with that of other European states of the day by 27 years of dedicated and industrious service.

  18. DdlN from Vancomycin-Producing Amycolatopsis orientalis C329.2 Is a VanA Homologue with d-Alanyl-d-Lactate Ligase Activity

    PubMed Central

    Marshall, C. Gary; Wright, Gerard D.

    1998-01-01

    Vancomycin-resistant enterococci acquire high-level resistance to glycopeptide antibiotics through the synthesis of peptidoglycan terminating in d-alanyl-d-lactate. A key enzyme in this process is a d-alanyl-d-alanine ligase homologue, VanA or VanB, which preferentially catalyzes the synthesis of the depsipeptide d-alanyl-d-lactate. We report the overexpression, purification, and enzymatic characterization of DdlN, a VanA and VanB homologue encoded by a gene of the vancomycin-producing organism Amycolatopsis orientalis C329.2. Evaluation of kinetic parameters for the synthesis of peptides and depsipeptides revealed a close relationship between VanA and DdlN in that depsipeptide formation was kinetically preferred at physiologic pH; however, the DdlN enzyme demonstrated a narrower substrate specificity and commensurately increased affinity for d-lactate in the C-terminal position over VanA. The results of these functional experiments also reinforce the results of previous studies that demonstrated that glycopeptide resistance enzymes from glycopeptide-producing bacteria are potential sources of resistance enzymes in clinically relevant bacteria. PMID:9791137

  19. Astronaut James van Hoften on RMS tracking Syncom IV-3 after deployment

    NASA Image and Video Library

    1985-09-01

    51I-41-086 (1 September 1985) --- Astronaut James D. van Hoften, mission specialist, flexes his muscles in celebration of a triumphant extravehicular task. Clouds over the ocean form the backdrop for this 70mm scene, toward the end of a two-day effort to capture, repair and release the previously errant Syncom IV-3 communications satellite. Van Hoften, anchored to a special foot restraint device on the end of Discovery's Remote Manipulator System (RMS), had just performed the final "shove" that started the relative separation of the Shuttle and the Syncom, which is not far out of frame. He had been joined by astronaut William F. Fisher for the busy two days of EVA.

  20. The Van Hiele geometry thinking levels of mild mental retardation students

    NASA Astrophysics Data System (ADS)

    Shomad, Z. A.; Kusmayadi, T. A.; Riyadi

    2017-12-01

    This research is to investigate the level of mild mental retardation geometry students thinking. This research focuses on the geometry thinking level based on Van Hiele theory. This study uses qualitative methods with case study strategy. Data obtained from observation and tests result. The subjects are 12 mental retardation students. The result show that ability of mild mental retardation students with each other is different but have same level of level thinking geometry. The geometry thinking level of mental retardation students was identified in level 1 of the Van Hiele theory. Based on the level thinking geometry of mental retardation students simplify geometry thinking teachers in selecting appropriate learning methods, choose the materials in accordance with ability, and can modify the material following the geometry thinking level of mental retardation students.

  1. Mixed Dimensional Van der Waals Heterostructures for Opto-Electronics.

    NASA Astrophysics Data System (ADS)

    Jariwala, Deep

    The isolation of a growing number of two-dimensional (2D) materials has inspired worldwide efforts to integrate distinct 2D materials into van der Waals (vdW) heterostructures. While a tremendous amount of research activity has occurred in assembling disparate 2D materials into ``all-2D'' van der Waals heterostructures, this concept is not limited to 2D materials alone. Given that any passivated, dangling bond-free surface will interact with another via vdW forces, the vdW heterostructure concept can be extended to include the integration of 2D materials with non-2D materials that adhere primarily through noncovalent interactions. In the first part of this talk I will present our work on emerging mixed-dimensional (2D + nD, where n is 0, 1 or 3) heterostructure devices performed at Northwestern University. I will present two distinct examples of gate-tunable p-n heterojunctions 1. Single layer n-type MoS2\\ (2D) combined with p-type semiconducting single walled carbon nanotubes (1D) and 2. Single layer MoS2 combined with 0D molecular semiconductor, pentacene. I will present the unique electrical properties, underlying charge transport mechanisms and photocurrent responses in both the above systems using a variety of scanning probe microscopy techniques as well as computational analysis. This work shows that van der Waals interactions are robust across different dimensionalities of materials and can allow fabrication of semiconductor devices with unique geometries and properties unforeseen in bulk semiconductors. Finally, I will briefly discuss our recent work from Caltech on near-unity absorption in atomically-thin photovoltaic devices. This work is supported by the Materials Research Center at Northwestern University, funded by the National Science Foundation (NSF DMR-1121262) and the Resnick Sustainability Institute at Caltech.

  2. Mammograms on-the-go-predictors of repeat visits to mobile mammography vans in St Louis, Missouri, USA: a case-control study.

    PubMed

    Drake, Bettina F; Abadin, Salmafatima S; Lyons, Sarah; Chang, Su-Hsin; Steward, Lauren T; Kraenzle, Susan; Goodman, Melody S

    2015-03-20

    Among women, breast cancer is the most common non-cutaneous cancer and second most common cause of cancer-related death. The purpose of this study was to determine the extent to which women use mobile mammography vans for breast cancer screening and what factors are associated with repeat visits to these vans. A case-control study. Cases are women who had a repeat visit to the mammography van. (n=2134). Women who received a mammogram as part of Siteman Cancer Center's Breast Health Outreach Program responded to surveys and provided access to their clinical records (N=8450). Only visits from 2006 to 2014 to the mammography van were included. The main outcome is having a repeat visit to the mammography van. Among the participants, 25.3% (N=2134) had multiple visits to the mobile mammography van. Data were analysed using χ(2) tests, logistic regression and negative binomial regression. Women who were aged 50-65, uninsured, or African-American had higher odds of a repeat visit to the mobile mammography van compared with women who were aged 40-50, insured, or Caucasian (OR=1.135, 95% CI 1.013 to 1.271; OR=1.302, 95% CI 1.146 to 1.479; OR=1.281, 95% CI 1.125 to 1.457), respectively. However, the odds of having a repeat visit to the van were lower among women who reported a rural ZIP code or were unemployed compared with women who provided a suburban ZIP code or were employed (OR=0.503, 95% CI 0.411 to 0.616; OR=.868, 95% CI 0.774 to 0.972), respectively. This study has identified key characteristics of women who are either more or less likely to use mobile mammography vans as their primary source of medical care for breast cancer screening and have repeat visits. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  3. Space Geoengineering: James A. Van Allen's Role in Detecting and Disrupting the Magnetosphere, 1958-1962 (Invited)

    NASA Astrophysics Data System (ADS)

    Fleming, J. R.

    2010-12-01

    James A. Van Allen’s celebrated discovery of Earth’s radiation belts in 1958 using Explorer 1 and 3 satellites was immediately followed by his agreement to monitor tests of nuclear weapons in space aimed at disrupting the magnetosphere. This is “space geoengineering” on a planetary scale. “Space is radioactive,” noted Van Allen’s colleague Eric Ray, and the military wanted to make it even more radioactive by nuclear detonations that, in time of war might disrupt enemy radio communications from half a world away and damage or destroy enemy intercontinental ballistic missiles. This study of Van Allen’s participation in Project Argus (1958) and Project Starfish (1962) is based on new posthumous accessions to the Van Allen Papers. At the time radio astronomers protested that, “No government has the right to change the environment in any significant way without prior international study and agreement.” Van Allen later regretted his participation in experiments that disrupted the natural magnetosphere. In a larger policy framework, the history of these space interventions and the protests they generated serve as a cautionary tale for today’s geoengineers who are proposing heavy-handed manipulation of the planetary environment as a response to future climate warming. Anyone claiming that geoengineering has not yet been attempted should be reminded of the planetary-scale engineering of these nukes in space. N. Christofilos describing the intended effect of the Argus nuclear explosions on the magnetosphere, which would direct a stream of radioactive particles along magnetic lines of force half a world away.

  4. 1. Photocopy of woodengraving by Van Vleck & Keith from ...

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

    1. Photocopy of wood-engraving by Van Vleck & Keith from a photograph by Shireff of Higgins' Daguerrian Rooms, Sacramento, with figures, etc. touched up by Nahl & Brothers. Illustration from The Californian Farmer, July 4, 1862. STANFORD HOUSE BY SETH BABSON, VIEW FROM THE NORTHEAST - Leland Stanford House, 800 N Street, Sacramento, Sacramento County, CA

  5. VanT, a Homologue of Vibrio harveyi LuxR, Regulates Serine, Metalloprotease, Pigment, and Biofilm Production in Vibrio anguillarum

    PubMed Central

    Croxatto, Antony; Chalker, Victoria J.; Lauritz, Johan; Jass, Jana; Hardman, Andrea; Williams, Paul; Cámara, Miguel; Milton, Debra L.

    2002-01-01

    Vibrio anguillarum possesses at least two N-acylhomoserine lactone (AHL) quorum-sensing circuits, one of which is related to the luxMN system of Vibrio harveyi. In this study, we have cloned an additional gene of this circuit, vanT, encoding a V. harveyi LuxR-like transcriptional regulator. A V. anguillarum ΔvanT null mutation resulted in a significant decrease in total protease activity due to loss of expression of the metalloprotease EmpA, but no changes in either AHL production or virulence. Additional genes positively regulated by VanT were identified from a plasmid-based gene library fused to a promoterless lacZ. Three lacZ fusions (serA::lacZ, hpdA-hgdA::lacZ, and sat-vps73::lacZ) were identified which exhibited decreased expression in the ΔvanT strain. SerA is similar to 3-phosphoglycerate dehydrogenases and catalyzes the first step in the serine-glycine biosynthesis pathway. HgdA has identity with homogentisate dioxygenases, and HpdA is homologous to 4-hydroxyphenylpyruvate dioxygenases (HPPDs) involved in pigment production. V. anguillarum strains require an active VanT to produce high levels of an l-tyrosine-induced brown color via HPPD, suggesting that VanT controls pigment production. Vps73 and Sat are related to Vibrio cholerae proteins encoded within a DNA locus required for biofilm formation. A V. anguillarum ΔvanT mutant and a mutant carrying a polar mutation in the sat-vps73 DNA locus were shown to produce defective biofilms. Hence, a new member of the V. harveyi LuxR transcriptional activator family has been characterized in V. anguillarum that positively regulates serine, metalloprotease, pigment, and biofilm production. PMID:11872713

  6. VanT, a homologue of Vibrio harveyi LuxR, regulates serine, metalloprotease, pigment, and biofilm production in Vibrio anguillarum.

    PubMed

    Croxatto, Antony; Chalker, Victoria J; Lauritz, Johan; Jass, Jana; Hardman, Andrea; Williams, Paul; Cámara, Miguel; Milton, Debra L

    2002-03-01

    Vibrio anguillarum possesses at least two N-acylhomoserine lactone (AHL) quorum-sensing circuits, one of which is related to the luxMN system of Vibrio harveyi. In this study, we have cloned an additional gene of this circuit, vanT, encoding a V. harveyi LuxR-like transcriptional regulator. A V. anguillarum Delta vanT null mutation resulted in a significant decrease in total protease activity due to loss of expression of the metalloprotease EmpA, but no changes in either AHL production or virulence. Additional genes positively regulated by VanT were identified from a plasmid-based gene library fused to a promoterless lacZ. Three lacZ fusions (serA::lacZ, hpdA-hgdA::lacZ, and sat-vps73::lacZ) were identified which exhibited decreased expression in the Delta vanT strain. SerA is similar to 3-phosphoglycerate dehydrogenases and catalyzes the first step in the serine-glycine biosynthesis pathway. HgdA has identity with homogentisate dioxygenases, and HpdA is homologous to 4-hydroxyphenylpyruvate dioxygenases (HPPDs) involved in pigment production. V. anguillarum strains require an active VanT to produce high levels of an L-tyrosine-induced brown color via HPPD, suggesting that VanT controls pigment production. Vps73 and Sat are related to Vibrio cholerae proteins encoded within a DNA locus required for biofilm formation. A V. anguillarum Delta vanT mutant and a mutant carrying a polar mutation in the sat-vps73 DNA locus were shown to produce defective biofilms. Hence, a new member of the V. harveyi LuxR transcriptional activator family has been characterized in V. anguillarum that positively regulates serine, metalloprotease, pigment, and biofilm production.

  7. VAN method of short-term earthquake prediction shows promise

    NASA Astrophysics Data System (ADS)

    Uyeda, Seiya

    Although optimism prevailed in the 1970s, the present consensus on earthquake prediction appears to be quite pessimistic. However, short-term prediction based on geoelectric potential monitoring has stood the test of time in Greece for more than a decade [VarotsosandKulhanek, 1993] Lighthill, 1996]. The method used is called the VAN method.The geoelectric potential changes constantly due to causes such as magnetotelluric effects, lightning, rainfall, leakage from manmade sources, and electrochemical instabilities of electrodes. All of this noise must be eliminated before preseismic signals are identified, if they exist at all. The VAN group apparently accomplished this task for the first time. They installed multiple short (100-200m) dipoles with different lengths in both north-south and east-west directions and long (1-10 km) dipoles in appropriate orientations at their stations (one of their mega-stations, Ioannina, for example, now has 137 dipoles in operation) and found that practically all of the noise could be eliminated by applying a set of criteria to the data.

  8. A Century after Van Allen's Birth: Conclusion of Reconnaissance of Radiation Belts in the Solar System

    NASA Astrophysics Data System (ADS)

    Krimigis, S. M.

    2014-12-01

    On May 1, 1958 in the Great Hall of the US National Academy of Sciences, James A. Van Allen, having instrumented Explorer-1 and follow-on satellites with radiation detectors, announced the discovery of intense radiation at high altitudes above Earth. The press dubbed the doughnut-shaped structures "Van Allen Belts" (VAB). Soon thereafter, the search began for VAB at nearby planets. Mariner 2 flew by Venus in 1962 at a distance of 41,000 km, but no radiation was detected. The Mariner 4 mission to Mars did not observe planet-associated increase in radiation, but scaling arguments with Earth's magnetosphere yielded an upper limit to the ratio of magnetic moments of MM/ME < 0.001 (Van Allen et al, 1965). Similarly, the Mariner 5 flyby closer to Venus resulted in a ratio of magnetic moments < 0.001 (Van Allen et al, 1967), dealing a blow to the expectation that all planetary bodies must possess significant VAB. The flyby of Mercury in 1974 by Mariner 10 revealed a weak magnetic field, but the presence of durably trapped higher energy particles remained controversial until MESSENGER in 2011.The first flybys of Jupiter by Pioneers 10, 11 in 1973 and 1974, respectively, measured a plethora of energetic particles in Jupiter's magnetosphere and established the fact that their intensities were rotationally modulated. Later flybys of Jupiter and Saturn by the two Voyagers in 1979 and 1981 revealed that those magnetospheres possessed their own internal plasma source(s) and radiation belts. Subsequent discoveries of Van Allen belts at Uranus and Neptune by Voyager 2 demonstrated that VAB are the rule rather than the exception in planetary environments. We now know from the Voyagers and through Energetic Neutral Atom images from Cassini and IBEX that an immense energetic particle population surrounds the heliosphere itself. Thus, the reconnaissance of radiation belts of our solar system has been completed, some 56 years after the discovery of the Van Allen Belts at Earth.

  9. Holographic Van der Waals phase transition of the higher-dimensional electrically charged hairy black hole

    NASA Astrophysics Data System (ADS)

    Li, Hui-Ling; Feng, Zhong-Wen; Zu, Xiao-Tao

    2018-01-01

    With motivation by holography, employing black hole entropy, two-point connection function and entanglement entropy, we show that, for the higher-dimensional Anti-de Sitter charged hairy black hole in the fixed charged ensemble, a Van der Waals-like phase transition can be observed. Furthermore, based on the Maxwell equal-area construction, we check numerically the equal-area law for a first order phase transition in order to further characterize the Van der Waals-like phase transition.

  10. Wild corvid birds colonized with vancomycin-resistant Enterococcus faecium of human origin harbor epidemic vanA plasmids.

    PubMed

    Oravcová, Veronika; Peixe, Luísa; Coque, Teresa M; Novais, Carla; Francia, Maria V; Literák, Ivan; Freitas, Ana R

    2018-06-02

    The most prevalent type of acquired vancomycin resistance in Enterococcus faecium (VREfm) is encoded by the vanA transposon Tn1546, mainly located on transferable plasmids. vanA plasmids have been characterized in VREfm from a variety of sources but not wild birds. The aim of this study was to analyse the genetic context of VREfm strains recovered from wild corvid birds and to compare their plasmid and strain characteristics with human strains. To achieve that, 75 VREfm isolates, including strains from wild birds recovered during wide surveillance studies performed in Europe, Canada and the United States (2010-2013), and clinical and wastewater strains from Czech Republic, a region lacking data about vanA plasmids, were analysed. Their population structure, presence of major putative virulence markers and characterization of vanA transposons and plasmids were established. VREfm from wild birds were mainly associated with major human lineages (ST18 and ST78) circulating in hospitals worldwide and were enriched in putative virulence markers that are highly associated with clinical E. faecium from human infections. They also carried plasmids of the same families usually found in the clinical setting [RCR, small theta plasmids, RepA_N (pRUM/pLG1) and Inc18]. The clinically widespread IS1251-carrying Tn1546 type "F" was predominant and Tn1546-vanA was mainly located on pRUM/Axe-Txe (USA) and Inc18- or pLG1-like (Europe) plasmids. VREfm from hospitals and wastewaters carried Tn1546-vanA in different plasmid types including mosaic pRUM-Inc18 plasmids, not identified in wild birds. This is the first characterization of vanA plasmids obtained from wild birds. A similar plasmid pool seems to exist in different clonal E. faecium backgrounds of humans and wild birds. The isolation of VREfm strains from wild birds that belong to human E. faecium adapted lineages and carry virulence genes, Tn1546 and plasmid variants widespread in the clinical setting is of concern and highlight

  11. Bell's palsy before Bell: Cornelis Stalpart van der Wiel's observation of Bell's palsy in 1683.

    PubMed

    van de Graaf, Robert C; Nicolai, Jean-Philippe A

    2005-11-01

    Bell's palsy is named after Sir Charles Bell (1774-1842), who has long been considered to be the first to describe idiopathic facial paralysis in the early 19th century. However, it was discovered that Nicolaus Anton Friedreich (1761-1836) and James Douglas (1675-1742) preceded him in the 18th century. Recently, an even earlier account of Bell's palsy was found, as observed by Cornelis Stalpart van der Wiel (1620-1702) from The Hague, The Netherlands in 1683. Because our current knowledge of the history of Bell's palsy before Bell is limited to a few documents, it is interesting to discuss Stalpart van der Wiel's description and determine its additional value for the history of Bell's palsy. It is concluded that Cornelis Stalpart van der Wiel was the first to record Bell's palsy in 1683. His manuscript provides clues for future historical research.

  12. Delivering Value by Preserving Values: An Interview with Douglas Van Houweling.

    ERIC Educational Resources Information Center

    EDUCAUSE Review, 2003

    2003-01-01

    Presents an interview with Douglas Van Houweling, president and CEO of the University Corporation for Advanced Internet Development (UCAID), the formal organization supporting Internet2, and recipient of the EDUCAUSE Award for Excellence in Leadership. (EV)

  13. van der Pauw's Theorem on Sheet Resistance

    ERIC Educational Resources Information Center

    Bolt, Michael

    2017-01-01

    The sheet resistance of a conducting material of uniform thickness is analogous to the resistivity of a solid material and provides a measure of electrical resistance. In 1958, L. J. van der Pauw found an effective method for computing sheet resistance that requires taking two electrical measurements from four points on the edge of a simply…

  14. Proteomic characterization of vanA-containing Enterococcus recovered from Seagulls at the Berlengas Natural Reserve, W Portugal.

    PubMed

    Radhouani, Hajer; Poeta, Patrícia; Pinto, Luís; Miranda, Júlio; Coelho, Céline; Carvalho, Carlos; Rodrigues, Jorge; López, María; Torres, Carmen; Vitorino, Rui; Domingues, Pedro; Igrejas, Gilberto

    2010-09-21

    Enterococci have emerged as the third most common cause of nosocomial infections, requiring bactericidal antimicrobial therapy. Although vancomycin resistance is a major problem in clinics and has emerged in an important extend in farm animals, few studies have examined it in wild animals. To determine the prevalence of vanA-containing Enterococcus strains among faecal samples of Seagulls (Larus cachinnans) of Berlengas Natural Reserve of Portugal, we developed a proteomic approach integrated with genomic data. The purpose was to detect the maximum number of proteins that vary in different enterococci species which are thought to be connected in some, as yet unknown, way to antibiotic resistance. From the 57 seagull samples, 54 faecal samples showed the presence of Enterococcus isolates (94.7%). For the enterococci, E. faecium was the most prevalent species in seagulls (50%), followed by E. faecalis and E. durans (10.4%), and E. hirae (6.3%). VanA-containing enterococcal strains were detected in 10.5% of the 57 seagull faecal samples studied. Four of the vanA-containing enterococci were identified as E. faecium and two as E. durans. The tet(M) gene was found in all five tetracycline-resistant vanA strains. The erm(B) gene was demonstrated in all six erythromycin-resistant vanA strains. The hyl virulence gene was detected in all four vanA-containing E. faecium isolates in this study, and two of them harboured the purK1 allele. In addition these strains also showed ampicillin and ciprofoxacin resistance. The whole-cell proteomic profile of vanA-containing Enterococcus strains was applied to evaluate the discriminatory power of this technique for their identification. The major differences among species-specific profiles were found in the positions corresponding to 97-45 kDa. Sixty individualized protein spots for each vanA isolate was identified and suitable for peptide mass fingerprinting measures by spectrometry measuring (MALDI/TOF MS) and their identification

  15. Proteomic characterization of vanA-containing Enterococcus recovered from Seagulls at the Berlengas Natural Reserve, W Portugal

    PubMed Central

    2010-01-01

    Background Enterococci have emerged as the third most common cause of nosocomial infections, requiring bactericidal antimicrobial therapy. Although vancomycin resistance is a major problem in clinics and has emerged in an important extend in farm animals, few studies have examined it in wild animals. To determine the prevalence of vanA-containing Enterococcus strains among faecal samples of Seagulls (Larus cachinnans) of Berlengas Natural Reserve of Portugal, we developed a proteomic approach integrated with genomic data. The purpose was to detect the maximum number of proteins that vary in different enterococci species which are thought to be connected in some, as yet unknown, way to antibiotic resistance. Results From the 57 seagull samples, 54 faecal samples showed the presence of Enterococcus isolates (94.7%). For the enterococci, E. faecium was the most prevalent species in seagulls (50%), followed by E. faecalis and E. durans (10.4%), and E. hirae (6.3%). VanA-containing enterococcal strains were detected in 10.5% of the 57 seagull faecal samples studied. Four of the vanA-containing enterococci were identified as E. faecium and two as E. durans. The tet(M) gene was found in all five tetracycline-resistant vanA strains. The erm(B) gene was demonstrated in all six erythromycin-resistant vanA strains. The hyl virulence gene was detected in all four vanA-containing E. faecium isolates in this study, and two of them harboured the purK1 allele. In addition these strains also showed ampicillin and ciprofoxacin resistance. The whole-cell proteomic profile of vanA-containing Enterococcus strains was applied to evaluate the discriminatory power of this technique for their identification. The major differences among species-specific profiles were found in the positions corresponding to 97-45 kDa. Sixty individualized protein spots for each vanA isolate was identified and suitable for peptide mass fingerprinting measures by spectrometry measuring (MALDI/TOF MS) and their

  16. Synthesis and activity study of phosphonamidate dipeptides as potential inhibitors of VanX.

    PubMed

    Yang, Ke-Wu; Cheng, Xu; Zhao, Chuan; Liu, Cheng-Cheng; Jia, Chao; Feng, Lei; Xiao, Jian-Min; Zhou, Li-Sheng; Gao, Hui-Zhou; Yang, Xia; Zhai, Le

    2011-12-01

    In an effort to develop inhibitors of VanX, the phosphonamidate analogs of D-Ala-D-Ala dipeptides, N-[(1-aminoethyl) hydroxyphosphinyl]-glycine (1a), -alanine (1b), -valine (1c), -leucine (1d) and -phenylalanine (1e) were synthesized, characterized and evaluated using recombinant VanX. The crystal structure of the intermediate 6d was obtained (Deposition number: CCDC 839134), and structural analysis revealed that it is orthorhombic with a space group P2(1)2(1)2(1), the bond length of P-N is 1.62Å and angle of C-N-P is 123.6°. Phosphonamidate 1(a-e) showed to be inhibitors of VanX with IC(50) values of 0.39, 0.70, 1.12, 2.82, and 4.13mM, respectively, which revealed that the inhibition activities of the phosphonamidates were dependent on the size of R-substituent of them, with the best inhibitor 1a having the smallest substituent. Also, 1a showed antibacterial activity against Staphylococcus aureus (ATCC 25923) with a MIC value of 0.25 μg/ml. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. Evaluation of van der Waals density functionals for layered materials

    NASA Astrophysics Data System (ADS)

    Tawfik, Sherif Abdulkader; Gould, Tim; Stampfl, Catherine; Ford, Michael J.

    2018-03-01

    In 2012, Björkman et al. posed the question "Are we van der Waals ready?" [T. Björkman et al., J. Phys.: Condens. Matter 24, 424218 (2012), 10.1088/0953-8984/24/42/424218] about the ability of ab initio modeling to reproduce van der Waals (vdW) dispersion forces in layered materials. The answer at that time was no, however. Here we report on a new generation of vdW dispersion models and show that one, i.e., the fractionally ionic atom theory with many-body dispersions, offers close to quantitative predictions for layered structures. Furthermore, it does so from a qualitatively correct picture of dispersion forces. Other methods, such as D3 and optB88vdW, also work well, albeit with some exceptions. We thus argue that we are nearly vdW ready and that some modern dispersion methods are accurate enough to be used for nanomaterial prediction, albeit with some caution required.

  18. Effect of van der Waals interactions on the structural and binding properties of GaSe

    SciTech Connect

    Sarkisov, Sergey Y., E-mail: sarkisov@mail.tsu.ru; Kosobutsky, Alexey V., E-mail: kosobutsky@kemsu.ru; Kemerovo State University, Krasnaya 6, 650043 Kemerovo

    The influence of van der Waals interactions on the lattice parameters, band structure, elastic moduli and binding energy of layered GaSe compound has been studied using projector-augmented wave method within density functional theory. We employed the conventional local/semilocal exchange-correlation functionals and recently developed van der Waals functionals which are able to describe dispersion forces. It is found that application of van der Waals density functionals allows to substantially increase the accuracy of calculations of the lattice constants a and c and interlayer distance in GaSe at ambient conditions and under hydrostatic pressure. The pressure dependences of the a-parameter, Ga–Ga, Ga–Semore » bond lengths and Ga–Ga–Se bond angle are characterized by a relatively low curvature, while c(p) has a distinct downward bowing due to nonlinear shrinking of the interlayer spacing. From the calculated binding energy curves we deduce the interlayer binding energy of GaSe, which is found to be in the range 0.172–0.197 eV/layer (14.2–16.2 meV/Å{sup 2}). - Highlights: • Effects of van der Waals interactions are analyzed using advanced density functionals. • Calculations with vdW-corrected functionals closely agree with experiment. • Interlayer binding energy of GaSe is estimated to be 14.2–16.2 meV/Å{sup 2}.« less

  19. Van der Waals model for phase transitions in thermoresponsive surface films.

    PubMed

    McCoy, John D; Curro, John G

    2009-05-21

    Phase transitions in polymeric surface films are studied with a simple model based on the van der Waals equation of state. Each chain is modeled by a single bead attached to the surface by an entropic-Hooke's law spring. The surface coverage is controlled by adjusting the chemical potential, and the equilibrium density profile is calculated with density functional theory. The interesting feature of this model is the multivalued nature of the density profile seen at low temperature. This van der Waals loop behavior is resolved with a Maxwell construction between a high-density phase near the wall and a low-density phase in a "vertical" phase transition. Signatures of the phase transition in experimentally measurable quantities are then found. Numerical calculations are presented for isotherms of surface pressure, for the Poisson ratio, and for the swelling ratio.

  20. Upscaled soil-water retention using van Genuchten's function

    USGS Publications Warehouse

    Green, T.R.; Constantz, J.E.; Freyberg, D.L.

    1996-01-01

    Soils are often layered at scales smaller than the block size used in numerical and conceptual models of variably saturated flow. Consequently, the small-scale variability in water content within each block must be homogenized (upscaled). Laboratory results have shown that a linear volume average (LVA) of water content at a uniform suction is a good approximation to measured water contents in heterogeneous cores. Here, we upscale water contents using van Genuchten's function for both the local and upscaled soil-water-retention characteristics. The van Genuchten (vG) function compares favorably with LVA results, laboratory experiments under hydrostatic conditions in 3-cm cores, and numerical simulations of large-scale gravity drainage. Our method yields upscaled vG parameter values by fitting the vG curve to the LVA of water contents at various suction values. In practice, it is more efficient to compute direct averages of the local vG parameter values. Nonlinear power averages quantify a feasible range of values for each upscaled vG shape parameter; upscaled values of N are consistently less than the harmonic means, reflecting broad pore-size distributions of the upscaled soils. The vG function is useful for modeling soil-water retention at large scales, and these results provide guidance for its application.

  1. Registered Replication Report: Dijksterhuis and van Knippenberg (1998).

    PubMed

    O'Donnell, Michael; Nelson, Leif D; Ackermann, Evi; Aczel, Balazs; Akhtar, Athfah; Aldrovandi, Silvio; Alshaif, Nasseem; Andringa, Ronald; Aveyard, Mark; Babincak, Peter; Balatekin, Nursena; Baldwin, Scott A; Banik, Gabriel; Baskin, Ernest; Bell, Raoul; Białobrzeska, Olga; Birt, Angie R; Boot, Walter R; Braithwaite, Scott R; Briggs, Jessie C; Buchner, Axel; Budd, Desiree; Budzik, Kathryn; Bullens, Lottie; Bulley, Richard L; Cannon, Peter R; Cantarero, Katarzyna; Cesario, Joseph; Chambers, Stephanie; Chartier, Christopher R; Chekroun, Peggy; Chong, Clara; Cleeremans, Axel; Coary, Sean P; Coulthard, Jacob; Cramwinckel, Florien M; Denson, Thomas F; Díaz-Lago, Marcos; DiDonato, Theresa E; Drummond, Aaron; Eberlen, Julia; Ebersbach, Titus; Edlund, John E; Finnigan, Katherine M; Fisher, Justin; Frankowska, Natalia; García-Sánchez, Efraín; Golom, Frank D; Graves, Andrew J; Greenberg, Kevin; Hanioti, Mando; Hansen, Heather A; Harder, Jenna A; Harrell, Erin R; Hartanto, Andree; Inzlicht, Michael; Johnson, David J; Karpinski, Andrew; Keller, Victor N; Klein, Olivier; Koppel, Lina; Krahmer, Emiel; Lantian, Anthony; Larson, Michael J; Légal, Jean-Baptiste; Lucas, Richard E; Lynott, Dermot; Magaldino, Corey M; Massar, Karlijn; McBee, Matthew T; McLatchie, Neil; Melia, Nadhilla; Mensink, Michael C; Mieth, Laura; Moore-Berg, Samantha; Neeser, Geraldine; Newell, Ben R; Noordewier, Marret K; Ali Özdoğru, Asil; Pantazi, Myrto; Parzuchowski, Michał; Peters, Kim; Philipp, Michael C; Pollmann, Monique M H; Rentzelas, Panagiotis; Rodríguez-Bailón, Rosa; Philipp Röer, Jan; Ropovik, Ivan; Roque, Nelson A; Rueda, Carolina; Rutjens, Bastiaan T; Sackett, Katey; Salamon, Janos; Sánchez-Rodríguez, Ángel; Saunders, Blair; Schaafsma, Juliette; Schulte-Mecklenbeck, Michael; Shanks, David R; Sherman, Martin F; Steele, Kenneth M; Steffens, Niklas K; Sun, Jessie; Susa, Kyle J; Szaszi, Barnabas; Szollosi, Aba; Tamayo, Ricardo M; Tinghög, Gustav; Tong, Yuk-Yue; Tweten, Carol; Vadillo, Miguel A; Valcarcel, Deisy; Van der Linden, Nicolas; van Elk, Michiel; van Harreveld, Frenk; Västfjäll, Daniel; Vazire, Simine; Verduyn, Philippe; Williams, Matt N; Willis, Guillermo B; Wood, Sarah E; Yang, Chunliang; Zerhouni, Oulmann; Zheng, Robert; Zrubka, Mark

    2018-03-01

    Dijksterhuis and van Knippenberg (1998) reported that participants primed with a category associated with intelligence ("professor") subsequently performed 13% better on a trivia test than participants primed with a category associated with a lack of intelligence ("soccer hooligans"). In two unpublished replications of this study designed to verify the appropriate testing procedures, Dijksterhuis, van Knippenberg, and Holland observed a smaller difference between conditions (2%-3%) as well as a gender difference: Men showed the effect (9.3% and 7.6%), but women did not (0.3% and -0.3%). The procedure used in those replications served as the basis for this multilab Registered Replication Report. A total of 40 laboratories collected data for this project, and 23 of these laboratories met all inclusion criteria. Here we report the meta-analytic results for those 23 direct replications (total N = 4,493), which tested whether performance on a 30-item general-knowledge trivia task differed between these two priming conditions (results of supplementary analyses of the data from all 40 labs, N = 6,454, are also reported). We observed no overall difference in trivia performance between participants primed with the "professor" category and those primed with the "hooligan" category (0.14%) and no moderation by gender.

  2. Reply to “Earthquake prediction evaluation standards applied to the VAN Method,” by D. D. Jackson

    NASA Astrophysics Data System (ADS)

    Varotsos, P.; Lazaridou, M.; Hadjicontis, V.

    Our earlier publications show that VAN method does not fail requirements (1) and (2) suggested by Jackson [1996]. No subjective ex-post facto decission was necessary for the evaluation of the success because, for the large majority of VAN predictions, the values of ΔM, Δr and Δt were published before the period 1987-1989 under discussion; in a few cases only (three out of 29), related with the observation of the new phenomenon of the SES electrical activity, the value of Δt was determined in 1988. Furthermore, a careful inspection-from physical point of view-shows that the three plausibility criteria, suggested by Jackson (to be obeyed by a candidate prediction technique), are actually met by VAN-method.

  3. Expectable Earthquakes and their ground motions in the Van Norman Reservoirs Area

    USGS Publications Warehouse

    Wesson, R.L.; Page, R.A.; Boore, D.M.; Yerkes, R.F.

    1974-01-01

    The upper and lower Van Norman dams, in northwesternmost San Fernando Valley about 20 mi (32 km) northwest of downtown Los Angeles, were severely damaged during the 1971 San Fernando earthquake. An investigation of the geologic-seismologic setting of the Van Norman area indicates that an earthquake of at least M 7.7 may be expected in the Van Norman area. The expectable transitory effects in the Van Norman area of such an earthquake are as follows: peak horizontal acceleration of at least 1.15 g, peak velocity of displacement of 4.43 ft/sec (135 cm/sec), peak displacement of 2.3 ft (70 cm), and duration of shaking at accelerations greater than 0.05 g, 40 sec. A great earthquake (M 8+) on the San Andreas fault, 25 mi distant, also is expectable. Transitory effects in the Van Norman area from such an earthquake are estimated as follows: peak horizontal acceleration of 0.5 g, peak velocity of 1.97 ft/sec (60 cm/sec), displacement of 1.31 ft (40 cm), and duration of shaking at accelerations greater than 0.05 g, 80 sec. The permanent effects of the expectable local earthquake could include simultaneous fault movement at the lower damsite, the upper damsite, and the site proposed for a replacement dam halfway between the upper and lower dams. The maximum differential displacements due to such movements are estimated at 16.4 ft (5 m) at the lower damsite and about 9.6 ft (2.93 m) at the upper and proposed damsites. The 1971 San Fernando earthquake (M 6?) was accompanied by the most intense ground motions ever recorded instrumentally for a natural earthquake. At the lower Van Norman dam, horizontal accelerations exceeded 0.6 g, and shaking greater than 0.25 g lasted for about 13 see; at Pacoima dam, 6 mi (10 km) northeast of the lower dam, high-frequency peak horizontal accelerations of 1.25 g were recorded in two directions, and shaking greater than 0.25 g lasted for about 7 sec. Permanent effects of the earthquake include slope failures in the embankments of the upper

  4. Encounters with John Van Vleck: Elevating the Self-Esteem of an Experimentalist

    NASA Astrophysics Data System (ADS)

    Wynne, James

    2011-03-01

    As a Harvard freshman in 1960, John H. Van Vleck was assigned to guide me through physics course selections. As a Harvard first year graduate student in 1964, I took his course on Group Theory. He was an esteemed theoretician, and I was an experimentalist. Nevertheless, I liked him, and he both educated me and gave me good advice. Later, I learned that Van Vleck was responsible for bringing Nicolaas Bloembergen, my Ph. D. advisor, back to Harvard from Holland, with a faculty appointment in the Division of Engineering and Applied Physics. (Bloembergen had done his Ph.D. thesis with Ed Purcell, making NMR into a science, and Purcell was one of the best teachers I encountered in 9 years at Harvard.) Stepping forward in time to May, 1969, just after defending my doctoral thesis, I ran into Van Vleck in the hallway. I told him I had earned my Ph.D., and he asked me what I had done for my thesis. Feeling defensive while talking to a great theoretician, I started out cautiously to say that I had built a carbon dioxide laser. He immediately started praising me as the best of the breed, someone who could build things and actually make them work. The praise continued, he told some stories (which I will share), and I left the building on ``Cloud 9.'' It was a really good day.

  5. van der Waals epitaxial ZnTe thin film on single-crystalline graphene

    NASA Astrophysics Data System (ADS)

    Sun, Xin; Chen, Zhizhong; Wang, Yiping; Lu, Zonghuan; Shi, Jian; Washington, Morris; Lu, Toh-Ming

    2018-01-01

    Graphene template has long been promoted as a promising host to support van der Waals flexible electronics. However, van der Waals epitaxial growth of conventional semiconductors in planar thin film form on transferred graphene sheets is challenging because the nucleation rate of film species on graphene is significantly low due to the passive surface of graphene. In this work, we demonstrate the epitaxy of zinc-blende ZnTe thin film on single-crystalline graphene supported by an amorphous glass substrate. Given the amorphous nature and no obvious remote epitaxy effect of the glass substrate, this study clearly proves the van der Waals epitaxy of a 3D semiconductor thin film on graphene. X-ray pole figure analysis reveals the existence of two ZnTe epitaxial orientational domains on graphene, a strong X-ray intensity observed from the ZnTe [ 1 ¯ 1 ¯ 2] ǁ graphene [10] orientation domain, and a weaker intensity from the ZnTe [ 1 ¯ 1 ¯ 2] ǁ graphene [11] orientation domain. Furthermore, this study systematically investigates the optoelectronic properties of this epitaxial ZnTe film on graphene using temperature-dependent Raman spectroscopy, steady-state and time-resolved photoluminescence spectroscopy, and fabrication and characterization of a ZnTe-graphene photodetector. The research suggests an effective approach towards graphene-templated flexible electronics.

  6. Defect mediated van der Waals epitaxy of hexagonal boron nitride on graphene

    NASA Astrophysics Data System (ADS)

    Heilmann, M.; Bashouti, M.; Riechert, H.; Lopes, J. M. J.

    2018-04-01

    Van der Waals heterostructures comprising of hexagonal boron nitride and graphene are promising building blocks for novel two-dimensional devices such as atomically thin transistors or capacitors. However, demonstrators of those devices have been so far mostly fabricated by mechanical assembly, a non-scalable and time-consuming method, where transfer processes can contaminate the surfaces. Here, we investigate a direct growth process for the fabrication of insulating hexagonal boron nitride on high quality epitaxial graphene using plasma assisted molecular beam epitaxy. Samples were grown at varying temperatures and times and studied using atomic force microscopy, revealing a growth process limited by desorption at high temperatures. Nucleation was mostly commencing from morphological defects in epitaxial graphene, such as step edges or wrinkles. Raman spectroscopy combined with x-ray photoelectron measurements confirm the formation of hexagonal boron nitride and prove the resilience of graphene against the nitrogen plasma used during the growth process. The electrical properties and defects in the heterostructures were studied with high lateral resolution by tunneling current and Kelvin probe force measurements. This correlated approach revealed a nucleation apart from morphological defects in epitaxial graphene, which is mediated by point defects. The presented results help understanding the nucleation and growth behavior during van der Waals epitaxy of 2D materials, and point out a route for a scalable production of van der Waals heterostructures.

  7. Temperature-Dependent and Gate-Tunable Rectification in a Black Phosphorus/WS2 van der Waals Heterojunction Diode.

    PubMed

    Dastgeer, Ghulam; Khan, Muhammad Farooq; Nazir, Ghazanfar; Afzal, Amir Muhammad; Aftab, Sikandar; Naqvi, Bilal Abbas; Cha, Janghwan; Min, Kyung-Ah; Jamil, Yasir; Jung, Jongwan; Hong, Suklyun; Eom, Jonghwa

    2018-04-18

    Heterostructures comprising two-dimensional (2D) semiconductors fabricated by individual stacking exhibit interesting characteristics owing to their 2D nature and atomically sharp interface. As an emerging 2D material, black phosphorus (BP) nanosheets have drawn much attention because of their small band gap semiconductor characteristics along with high mobility. Stacking structures composed of p-type BP and n-type transition metal dichalcogenides can produce an atomically sharp interface with van der Waals interaction which leads to p-n diode functionality. In this study, for the first time, we fabricated a heterojunction p-n diode composed of BP and WS 2 . The rectification effects are examined for monolayer, bilayer, trilayer, and multilayer WS 2 flakes in our BP/WS 2 van der Waals heterojunction diodes and also verified by density function theory calculations. We report superior functionalities as compared to other van der Waals heterojunction, such as efficient gate-dependent static rectification of 2.6 × 10 4 , temperature dependence, thickness dependence of rectification, and ideality factor of the device. The temperature dependence of Zener breakdown voltage and avalanche breakdown voltage were analyzed in the same device. Additionally, superior optoelectronic characteristics such as photoresponsivity of 500 mA/W and external quantum efficiency of 103% are achieved in the BP/WS 2 van der Waals p-n diode, which is unprecedented for BP/transition metal dichalcogenides heterostructures. The BP/WS 2 van der Waals p-n diodes have a profound potential to fabricate rectifiers, solar cells, and photovoltaic diodes in 2D semiconductor electronics and optoelectronics.

  8. Influence of van der Waals forces on increasing the strength and toughness in dynamic fracture of nanofibre networks: a peridynamic approach

    NASA Astrophysics Data System (ADS)

    Bobaru, F.

    2007-07-01

    The peridynamic method is used here to analyse the effect of van der Waals forces on the mechanical behaviour and strength and toughness properties of three-dimensional nanofibre networks under imposed stretch deformation. The peridynamic formulation allows for a natural inclusion of long-range forces (such as van der Waals forces) by considering all interactions as 'long-range'. We use van der Waals interactions only between different fibres and do not need to model individual atoms. Fracture is introduced at the microstructural (peridynamic bond) level for the microelastic type bonds, while van der Waals bonds can reform at any time. We conduct statistical studies to determine a certain volume element for which the network of randomly oriented fibres becomes quasi-isotropic and insensitive to statistical variations. This qualitative study shows that the presence of van der Waals interactions and of heterogeneities (sacrificial bonds) in the strength of the bonds at the crosslinks between fibres can help in increasing the strength and toughness of the nanofibre network. Two main mechanisms appear to control the deformation of nanofibre networks: fibre reorientation (caused by deformation and breakage) and fibre accretion (due to van der Waals interaction). Similarities to the observed toughness of polymer adhesive in the abalone shell composition are explained. The author would like to dedicate this work to the 60th anniversary of Professor Subrata Mukherjee.

  9. Astronauts Lodewijk van den Berg observes growth of crystals in VCGS

    NASA Image and Video Library

    1985-04-30

    51B-06-010 (29 April-6 May 1985) --- Lodewijk van den Berg, 51-B payload specialist, observes the growth of mercuric iodide crystal in the vapor crystal growth system (VCGS) on the Spacelab 3 science module aboard the Space Shuttle Challenger.

  10. Paint it Black: Using Change-Point Analysis to Investigate Increasing Vulnerability to Depression towards the End of Vincent van Gogh's Life.

    PubMed

    van Emmerik, Arnold A P; Hamaker, Ellen L

    2017-09-04

    This study investigated whether Vincent van Gogh became increasingly self-focused-and thus vulnerable to depression-towards the end of his life, through a quantitative analysis of his written pronoun use over time. A change-point analysis was conducted on the time series formed by the pronoun use in Van Gogh's letters. We used time as a predictor to see whether there was evidence for increased self-focus towards the end of Van Gogh's life, and we compared this to the pattern in the letters written before his move to Arles. Specifically, we examined Van Gogh's use of first person singular pronouns (FPSP) and first person plural pronouns (FPPP) in the 415 letters he wrote while working as an artist before his move to Arles, and in the next 248 letters he wrote after his move to Arles until his death in Auvers-sur-Oise. During the latter period, Van Gogh's use of FPSP showed an annual increase of 0.68% ( SE = 0.15, p < 0.001) and his use of FPPP showed an annual decrease of 0.23% ( SE = 0.04, p < 0.001), indicating increasing self-focus and vulnerability to depression. This trend differed from Van Gogh's pronoun use in the former period (which showed no significant trend in FPSP, and an annual increase of FPPP of 0.03%, SE = 0.02, p = 0.04). This study suggests that Van Gogh's death was preceded by a gradually increasing self-focus and vulnerability to depression. It also illustrates how existing methods (i.e., quantitative linguistic analysis and change-point analysis) can be combined to study specific research questions in innovative ways.

  11. Interlayer excitons in a bulk van der Waals semiconductor.

    PubMed

    Arora, Ashish; Drüppel, Matthias; Schmidt, Robert; Deilmann, Thorsten; Schneider, Robert; Molas, Maciej R; Marauhn, Philipp; Michaelis de Vasconcellos, Steffen; Potemski, Marek; Rohlfing, Michael; Bratschitsch, Rudolf

    2017-09-21

    Bound electron-hole pairs called excitons govern the electronic and optical response of many organic and inorganic semiconductors. Excitons with spatially displaced wave functions of electrons and holes (interlayer excitons) are important for Bose-Einstein condensation, superfluidity, dissipationless current flow, and the light-induced exciton spin Hall effect. Here we report on the discovery of interlayer excitons in a bulk van der Waals semiconductor. They form due to strong localization and spin-valley coupling of charge carriers. By combining high-field magneto-reflectance experiments and ab initio calculations for 2H-MoTe 2 , we explain their salient features: the positive sign of the g-factor and the large diamagnetic shift. Our investigations solve the long-standing puzzle of positive g-factors in transition metal dichalcogenides, and pave the way for studying collective phenomena in these materials at elevated temperatures.Excitons, quasi-particles of bound electron-hole pairs, are at the core of the optoelectronic properties of layered transition metal dichalcogenides. Here, the authors unveil the presence of interlayer excitons in bulk van der Waals semiconductors, arising from strong localization and spin-valley coupling of charge carriers.

  12. Kennislacunes op het gebied van wapens en munitie in OVG (Knowledge Gaps in the Area of Weapons and Munitions in MOUT)

    DTIC Science & Technology

    2008-12-01

    Structuur 6 2.2 Inzetketen 8 2.3 Combinaties van W&M en doelen 9 2.4 Militaire activiteiten 10 3 De OVG context 11 4 Kennislacunes wapens en...Aanlal pagina’s Aantal bijlagen Ongerubriceerd drs. R.G.W. Gouweleeuw 7 november 2008 11 )eze mbricering \\N ijzigl mci) Ongerubriceerd...TNO-rapport | TNO-DV 2008 A436 9 /24 2.3 Combinaties van W&M en doelen In [2] is een overzicht opgesteld van zogenoemde ’force assets’ die tegen

  13. Van der Waals Epitaxy of Functional Oxide Heterostructures

    NASA Astrophysics Data System (ADS)

    Chu, Ying-Hao

    In the diligent pursuit of low-power consumption, multifunctional, and environmentally friendly electronics, more sophisticated requirements on functional materials are on demand. Recently, the discovery of 2D layered materials has created a revolution to this field. Pioneered by graphene, these new 2D materials exhibit abundant unusual physical phenomena that is undiscovered in bulk forms. These materials are characterized with their layer form and almost pure 2D electronic behavior. The confinement of charge and heat transport at such ultrathin planes offers possibilities to overcome the bottleneck of present device development in thickness limitation, and thus push the technologies into next generation. Van der Waals epitaxy, an epitaxial growth method to combine 2D and 3D materials, is one of current reliable manufacturing processes to fabricate 2D materials by growing these 2D materials epitaxially on 3D materials. Then, transferring the 2D materials to the substrates for practical applications. In the mean time, van der Waals epitaxy has also been used to create free-standing 3D materials by growing 3D materials on 2D materials and then removing them from 2D materials since the interfacial boding between 2D and 3D materials should be weak van der Waals bonds. In this study, we intend to take the same concept, but to integrate a family of functional materials in order to open new avenue to flexible electronics. Due to the interplay of lattice, charge, orbital, and spin degrees of freedom, correlated electrons in oxides generate a rich spectrum of competing phases and physical properties. Recently, lots of studies have suggested that oxide heterostructures provide a powerful route to create and manipulate the degrees of freedom and offer new possibilities for next generation devices, thus create a new playground for researchers to investigate novel physics and the emergence of fascinating states of condensed matter. In this talk, we use a 2D layered material as

  14. Loops of Jupiter

    NASA Astrophysics Data System (ADS)

    Opolski, Antoni

    2014-12-01

    Professor Antoni Opolski was actively interested in astronomy after his retirement in 1983. He especially liked to study the works of the famous astronomer Copernicus getting inspiration for his own work. Opolski started his work on planetary loops in 2011 continuing it to the end of 2012 . During this period calculations, drawings, tables, and basic descriptions of all the planets of the Solar System were created with the use of a piece of paper and a pencil only. In 2011 Antoni Opolski asked us to help him in editing the manuscript and preparing it for publication. We have been honored having the opportunity to work on articles on planetary loops with Antoni Opolski in his house for several months. In the middle of 2012 the detailed material on Jupiter was ready. However, professor Opolski improved the article by smoothing the text and preparing new, better drawings. Finally the article ''Loops of Jupiter'', written by the 99- year old astronomer, was published in the year of his 100th birthday.

  15. Astronaut James D. van Hoften examines student experiment on Challenger

    NASA Image and Video Library

    1984-04-15

    41C-05-188 (12 April 1984) --- Astronaut James D. van Hoften, mission specialist, holds an aluminum box, full of honeybees. The experiment in Earth-orbit is duplicated with another colony of the young honeycomb builders on Earth. Dan Poskevich submitted the experiment to NASA as part of the Shuttle student involvement program.

  16. Control of excitons in multi-layer van der Waals heterostructures

    SciTech Connect

    Calman, E. V., E-mail: ecalman@gmail.com; Dorow, C. J.; Fogler, M. M.

    2016-03-07

    We report an experimental study of excitons in a double quantum well van der Waals heterostructure made of atomically thin layers of MoS{sub 2} and hexagonal boron nitride. The emission of neutral and charged excitons is controlled by gate voltage, temperature, and both the helicity and the power of optical excitation.

  17. Van tells residential conservation story. [Potomac Edison Co. of Allegheny Power System

    SciTech Connect

    Not Available

    1976-01-15

    Potomac Edison Co. is taking its residential energy-conservation story to the public via a mobile van that will be on display at schools, service clubs, shopping centers, fairs, and exhibits. The van is equiped with exhibits featuring the latest in energy-saving equipment and techniques in insulation, ventilation, hot water, solar energy, load control, fireplace heat control, utility billing, appliances, appliance efficiency, lighting, heat pump, and furnace heat recovery. The exhibits are not limited to electrical applications. One shows the effect that an orifice installed in a shower head has on the amount of hot water used. The device cuts themore » amounts of both water and energy use to about one-half. Each display item is readily available from local sources. (MCW)« less

  18. Episodic cluster headache from a textbook of 1745: van Swieten's classic description.

    PubMed

    Isler, H

    1993-06-01

    The first description of cluster headache is usually attributed to authors who published between 1867 and 1939, but lately several researchers have found accounts dating back to the 18th or even the 17th century which are incomplete or do not account for cluster headache in the strict sense. However, Gerhard van Swieten gave a full description of a case of episodic cluster headache meeting the IHS criteria in 1745, in his textbook of clinical medicine, the mainstream textbook of Continental medicine in those years, since van Swieten was the founder of the then leading medical centre, the Vienna School. That the case was found again only in 1992 is due to the circumstance that it was published in Latin. It is presented here in an English translation facing the original Latin text.

  19. Tactisch Optreden van kleine eenheden (Small Unit Tactics)

    DTIC Science & Technology

    2007-08-01

    Marechaussee KTS Knock, Talk and Search MB Mercedes Benz MND(SE) Multinational Division (South East) NAVO Noord Atlantische Verdrag Organisatie NGO Non...patrouilles had men de beschikking over Mercedes Benz (MB) soft top wielvoertuigen, met een mitrailleur MAG 7.62 mm op affuit. Als extra bescherming was het... Mercedes Benz 5 IkN/ 7.5 kN soft top) voorzien van een voertuigaffuit met een mitrailleur MAG 7,62mm, uitgevoerd (zie Figuur 8). Bij verhoogde dreiging

  20. Strong van der Waals attractive forces in nanotechnology

    NASA Astrophysics Data System (ADS)

    Reimers, Jeffrey

    The Dobson classification scheme for failure of London-like expressions for describing dispersion is reviewed. New ways to measure using STM data and calculate by first principles free energies of organic self-assembly processes from solution will be discussed, considering tetraalkylporphyrins on graphite. How strong van der Waals forces can compete against covalent bonding to produce new molecular isomers and reaction pathways will also be demonstrated, focusing on golds-sulfur bonds for sensors and stabilizing nanoparticles.

  1. Kwaliteit van Expertsystemen: Algoritmen voor Integriteits-Controle (Quality of Expert Systems: Algorithms for Integrity Control)

    DTIC Science & Technology

    1990-03-01

    Dist~i~ Ulnre rbu~ on Una o~d0 9 ~ j 2 0 0 TNO rapport Pagina rappon no. .FEL-89-A312 f"It Kwaliteit van Expertsystemen: Algoritmen voor Integriteits...KNOWLEDGEBASE 7 2.1 Inleiding 7 2.2 Een uitbreiding op NIAM: E(xtended)NIAM 8 2.3 Specificatie in E(xtended)NIAM 11 2.4 Representatie in Prolog 13 3...instantiatie van cen ThO rapport Pagina 9 ’graph’ is gelijk aan ten propositie (ean uitspraak over dea werkelijkheid). ’Graph’- instantiaties zijn

  2. Meaning, lived experience, empathy and boredom: Max van Manen on phenomenology and Heidegger.

    PubMed

    Paley, John

    2018-07-01

    Phenomenology as Qualitative Research: A Critical Analysis of Meaning Attribution has attracted the attention of Max van Manen, who has published a highly critical review article. Anyone reading this article, but unfamiliar with the book, will get a distorted view of what it is about, whom it is addressed to, what it tries to achieve, and how it goes about presenting its arguments. Not mildly distorted, in need of the odd correction here and there, but systematically misrepresented. One problem is that van Manen appears to have an idée fixe which prevents him from recognizing that the book is not about a certain philosophical tradition (known as "phenomenology"), but about a particular type of qualitative research (also known, unfortunately and confusingly, as "phenomenology"). A second idée fixe disposes him to misread an earlier article of mine and (much more seriously) three works by Heidegger. My aim in this article is to describe these two idées fixes, and exhibit their consequences. In doing so, I will examine what van Manen has to say on four crucial topics: meaning, lived experience, empathy, and Heidegger's analysis of boredom in The Fundamental Concepts of Metaphysics. © 2018 John Wiley & Sons Ltd.

  3. Programme for Learning Enrichment. A Van Leer Project: An Evaluation.

    ERIC Educational Resources Information Center

    Ghani, Zainal

    This paper reports the evaluation of a project undertaken by the Sarawak Education Department to improve the quality of education in upper primary classes in rural Sarawak, Malaysia. The project is known officially as the Programme for Learning Enrichment, and commonly as the Van Leer Project, after the international agency which provides the main…

  4. Beslisbevoegdheden van de Uitgestegen Soldaat. Deel B: Verbetering van Situational Awareness Met Behulp van de Soldier Digital Assistant in een Gesimuleerde Omgeving (Authority and Responsbility of the Dismounted Soldier. Part B. Improving the Situational Awareness using the Soldier Digital Assistant in a Simulated Environment)

    DTIC Science & Technology

    2007-04-01

    Dergelijke omngevingen zijn tot op heden vrijwel uitsluitend gebruikt voor training en onderwijs , maar slechts zeer sporadisch voor wetenschappelijk...Onderstaande instanties/personen ontvangen een volledig exemplaar van het rapport. 1 DMO/SC-DR&D standaard inclusief digitale versie bijgeleverd op cd

  5. The ambivalence of the maternal body: psychoanalytic readings of the legend of Van Gogh.

    PubMed

    Pollock, G

    1994-08-01

    This article aims to identify the collective social investment in 'Van Gogh' as a cultural icon, and to ask what function his life story, colourfully illustrated by his art work, has performed in the West since the 1890s. It argues that the life and work of a Dutch artist have become the raw materials for a series of secular 'mystery' plays and christological psychodramas that reflect the ills of twentieth-century experience. The key moments when Van Gogh was made into a figure in a popular imagination were psychologically significant: the Depression and the immediate aftermath of World War II. 'Van Gogh', a fantasy figure of modern man, has been over-'psychologised', his work becoming only the testament to the myth of modern man. Using social-art-historical techniques, the author tries to distance this kind of reading in the case of one drawing of a peasant woman, bending over. Situating the fantasy that the drawing services in precise social and historical terms of bourgeois men formed in childhood in relation to a split feminine/maternal figure of the lady/mother and the working-class nursemaid, the article examines how to use psychoanalysis to read the formal oddities of the work--distortion and monumentality, attention to a fragmented, eroticised but also punished body--for the oscillation between pre-oedipal fantasies of maternal plenitude and awe and oedipal anxieties which sadistically inflict humiliation on the maternal body. Finally, instead of producing Van Gogh as the extreme case of an 'other', the author recognises the drawing as a space where present fantasies of the reader encounter those of the producer. Psychoanalysis informing historically-precise interpretation becomes a demythologising hermeneutic.

  6. Quantum Monte Carlo Simulation of condensed van der Waals Systems

    NASA Astrophysics Data System (ADS)

    Benali, Anouar; Shulenburger, Luke; Romero, Nichols A.; Kim, Jeongnim; Anatole von Lilienfeld, O.

    2012-02-01

    Van der Waals forces are as ubiquitous as infamous. While post-Hartree-Fock methods enable accurate estimates of these forces in molecules and clusters, they remain elusive for dealing with many-electron condensed phase systems. We present Quantum Monte Carlo [1,2] results for condensed van der Waals systems. Interatomic many-body contributions to cohesive energies and bulk modulus will be discussed. Numerical evidence is presented for crystals of rare gas atoms, and compared to experiments and methods [3]. Sandia National Laboratories is a multiprogram laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. DoE's National Nuclear Security Administration under Contract No. DE-AC04-94AL85000.[4pt] [1] J. Kim, K. Esler, J. McMinis and D. Ceperley, SciDAC 2010, J. of Physics: Conference series, Chattanooga, Tennessee, July 11 2011 [0pt] [2] QMCPACK simulation suite, http://qmcpack.cmscc.org (unpublished)[0pt] [3] O. A. von Lillienfeld and A. Tkatchenko, J. Chem. Phys. 132 234109 (2010)

  7. EDITORIAL: Van der Waals interactions in advanced materials, in memory of David C Langreth Van der Waals interactions in advanced materials, in memory of David C Langreth

    NASA Astrophysics Data System (ADS)

    Hyldgaard, Per; Rahman, Talat S.

    2012-10-01

    Solid State Commun. 17 1425 [4]Gunnarsson O and Lundqvist B I 1976 Exchange and correlation in atoms, molecules, and solids by the spin-density-functional formalism Phys. Rev. B 13 4274 [5]Langreth D C and Mehl M J 1981 Beyond the local-density approximation in calculations of ground-state electronic properties Phys. Rev. B 47 446 [6]Dion M, Rydberg H, Schröder E, Langreth D C and Lundqvist B I 2004 Van der Waals density functional for general geometries Phys. Rev. Lett. 92 246401 Thonhauser T, Cooper V R, Li S, Puzder A, Hyldgaard P and Langreth D C 2007 Van der Waals density functional: self-consistent potential and the nature of the van der Waals bond Phys. Rev. B 76 125112 [7]Lee K, Murray E D, Kong L, Lundqvist B I and Langreth D C 2010 A higher-accuracy van der Waals density functional Phys. Rev. B 82 081101 [8]Rapcewicz K and Ashcroft N W 1991 Fluctuation attraction in condensed matter: a nonlocal functional approach Phys. Rev. B 44 4032 Lundqvist B I, Andersson Y, Shao H, Chan S and Langreth D C 1995 Density functional theory including van der Waals forces Int. J. Quant. Chem. 56 247 [9]Langreth D C et al 2009 A density functional for sparse matter J. Phys.: Condens. Matter 21 084203 [10]For example, Kohn W, Meir Y and Makarov D E 1998 The exchange-correlation energy of a metallic surface Phys. Rev. Lett. 80 4153 Kurth S and Perdew J P 1999 Phys. Rev. B 59 10461 Dobson J F and Wang J 1999 Phys. Rev. Lett. 82 2123 Pitarke J M and Perdew J P 2003 Phys. Rev. B 67 045101 Vydrov O A and van Voorhi T 2009 Phys. Rev. Lett. 103 063004 [11]For example, Grimme S 2004 J. Comput. Phys. 25 1463 Tkatchenko A and Scheffler M 2009 Phys. Rev. Lett. 102 073005 Grimme S, Antony J, Ehrlich S and Krieg H 2010 J. Chem. Phys. 132 154004 [12]Burke K 2012 Perspectives on density functional theory J. Chem. Phys. 136 150901 Van der Waals interactions in advanced materials contents Van der Waals interactions in advanced materials, in memory of David C LangrethPer Hyldgaard and Talat S

  8. Comparison of SPT and V s-based liquefaction analyses: a case study in Erciş (Van, Turkey)

    NASA Astrophysics Data System (ADS)

    Akkaya, İsmail; Özvan, Ali; Akin, Mutluhan; Akin, Müge K.; Övün, Uğur

    2017-12-01

    Liquefaction which is one of the most destructive ground deformations occurs during an earthquake in saturated or partially saturated silty and sandy soils, which may cause serious damages such as settlement and tilting of structures due to shear strength loss of soils. Standard (SPT) and cone (CPT) penetration tests as well as the shear wave velocity (V s)-based methods are commonly used for the determination of liquefaction potential. In this research, it was aimed to compare the SPT and V s-based liquefaction analysis methods by generating different earthquake scenarios. Accordingly, the Erciş residential area, which was mostly affected by the 2011 Van earthquake (M w = 7.1), was chosen as the model site. Erciş (Van, Turkey) and its surroundings settle on an alluvial plain which consists of silty and sandy layers with shallow groundwater level. Moreover, Çaldıran, Erciş-Kocapınar and Van Fault Zones are the major seismic sources of the region which have a significant potential of producing large magnitude earthquakes. After liquefaction assessments, the liquefaction potential in the western part of the region and in the coastal regions nearby the Lake Van is found to be higher than the other locations. Thus, it can be stated that the soil tightness and groundwater level dominantly control the liquefaction potential. In addition, the lateral spreading and sand boiling spots observed after the 23rd October 2011 Van earthquake overlap the scenario boundaries predicted in this study. Eventually, the use of V s-based liquefaction analysis in collaboration with the SPT results is quite advantageous to assess the rate of liquefaction in a specific area.

  9. Comparison of SPT and V s-based liquefaction analyses: a case study in Erciş (Van, Turkey)

    NASA Astrophysics Data System (ADS)

    Akkaya, İsmail; Özvan, Ali; Akin, Mutluhan; Akin, Müge K.; Övün, Uğur

    2018-02-01

    Liquefaction which is one of the most destructive ground deformations occurs during an earthquake in saturated or partially saturated silty and sandy soils, which may cause serious damages such as settlement and tilting of structures due to shear strength loss of soils. Standard (SPT) and cone (CPT) penetration tests as well as the shear wave velocity ( V s)-based methods are commonly used for the determination of liquefaction potential. In this research, it was aimed to compare the SPT and V s-based liquefaction analysis methods by generating different earthquake scenarios. Accordingly, the Erciş residential area, which was mostly affected by the 2011 Van earthquake ( M w = 7.1), was chosen as the model site. Erciş (Van, Turkey) and its surroundings settle on an alluvial plain which consists of silty and sandy layers with shallow groundwater level. Moreover, Çaldıran, Erciş-Kocapınar and Van Fault Zones are the major seismic sources of the region which have a significant potential of producing large magnitude earthquakes. After liquefaction assessments, the liquefaction potential in the western part of the region and in the coastal regions nearby the Lake Van is found to be higher than the other locations. Thus, it can be stated that the soil tightness and groundwater level dominantly control the liquefaction potential. In addition, the lateral spreading and sand boiling spots observed after the 23rd October 2011 Van earthquake overlap the scenario boundaries predicted in this study. Eventually, the use of V s-based liquefaction analysis in collaboration with the SPT results is quite advantageous to assess the rate of liquefaction in a specific area.

  10. Effect of van der Waals forces on thermal conductance at the interface of a single-wall carbon nanotube array and silicon

    NASA Astrophysics Data System (ADS)

    Feng, Ya; Zhu, Jie; Tang, Dawei

    2014-12-01

    Molecular dynamics simulations are performed to evaluate the effect of van der Waals forces among single-wall carbon nanotubes (SWNTs) on the interfacial thermal conductance between a SWNT array and silicon substrate. First, samples of SWNTs vertically aligned on silicon substrate are simulated, where both the number and arrangement of SWNTs are varied. Results reveal that the interfacial thermal conductance of a SWNT array/Si with van der Waals forces present is higher than when they are absent. To better understand how van der Waals forces affect heat transfer through the interface between SWNTs and silicon, further constructs of one SWNT surrounded by different numbers of other ones are studied, and the results show that the interfacial thermal conductance of the central SWNT increases with increasing van der Waals forces. Through analysis of the covalent bonds and vibrational density of states at the interface, we find that heat transfer across the interface is enhanced with a greater number of chemical bonds and that improved vibrational coupling of the two sides of the interface results in higher interfacial thermal conductance. Van der Waals forces stimulate heat transfer at the interface.

  11. Exploring students’ adaptive reasoning skills and van Hiele levels of geometric thinking: a case study in geometry

    NASA Astrophysics Data System (ADS)

    Rizki, H. T. N.; Frentika, D.; Wijaya, A.

    2018-03-01

    This study aims to explore junior high school students’ adaptive reasoning and the Van Hiele level of geometric thinking. The present study was a quasi-experiment with the non-equivalent control group design. The participants of the study were 34 seventh graders and 35 eighth graders in the experiment classes and 34 seventh graders and 34 eighth graders in the control classes. The students in the experiment classes learned geometry under the circumstances of a Knisley mathematical learning. The data were analyzed quantitatively by using inferential statistics. The results of data analysis show an improvement of adaptive reasoning skills both in the grade seven and grade eight. An improvement was also found for the Van Hiele level of geometric thinking. These results indicate the positive impact of Knisley learning model on students’ adaptive reasoning skills and Van Hiele level of geometric thinking.

  12. A Neural Network Approach for Identifying Particle Pitch Angle Distributions in Van Allen Probes Data

    NASA Technical Reports Server (NTRS)

    Souza, V. M.; Vieira, L. E. A.; Medeiros, C.; Da Silva, L. A.; Alves, L. R.; Koga, D.; Sibeck, D. G.; Walsh, B. M.; Kanekal, S. G.; Jauer, P. R.; hide

    2016-01-01

    Analysis of particle pitch angle distributions (PADs) has been used as a means to comprehend a multitude of different physical mechanisms that lead to flux variations in the Van Allen belts and also to particle precipitation into the upper atmosphere. In this work we developed a neural network-based data clustering methodology that automatically identifies distinct PAD types in an unsupervised way using particle flux data. One can promptly identify and locate three well-known PAD types in both time and radial distance, namely, 90deg peaked, butterfly, and flattop distributions. In order to illustrate the applicability of our methodology, we used relativistic electron flux data from the whole month of November 2014, acquired from the Relativistic Electron-Proton Telescope instrument on board the Van Allen Probes, but it is emphasized that our approach can also be used with multiplatform spacecraft data. Our PAD classification results are in reasonably good agreement with those obtained by standard statistical fitting algorithms. The proposed methodology has a potential use for Van Allen belt's monitoring.

  13. Do bees like Van Gogh's Sunflowers?

    NASA Astrophysics Data System (ADS)

    Chittka, Lars; Walker, Julian

    2006-06-01

    Flower colours have evolved over 100 million years to address the colour vision of their bee pollinators. In a much more rapid process, cultural (and horticultural) evolution has produced images of flowers that stimulate aesthetic responses in human observers. The colour vision and analysis of visual patterns differ in several respects between humans and bees. Here, a behavioural ecologist and an installation artist present bumblebees with reproductions of paintings highly appreciated in Western society, such as Van Gogh's Sunflowers. We use this unconventional approach in the hope to raise awareness for between-species differences in visual perception, and to provoke thinking about the implications of biology in human aesthetics and the relationship between object representation and its biological connotations.

  14. Communication: Determining the structure of the N{sub 2}Ar van der Waals complex with laser-based channel-selected Coulomb explosion

    SciTech Connect

    Wu, Chengyin, E-mail: cywu@pku.edu.cn; Liu, Yunquan; Gong, Qihuang

    2014-04-14

    We experimentally reconstructed the structure of the N{sub 2}Ar van der Waals complex with the technique of laser-based channel-selected Coulomb explosion imaging. The internuclear distance between the N{sub 2} center of mass and the Ar atom, i.e., the length of the van der Waals bond, was determined to be 3.88 Å from the two-body explosion channels. The angle between the van der Waals bond and the N{sub 2} principal axis was determined to be 90° from the three-body explosion channels. The reconstructed structure was contrasted with our high level ab initio calculations. The agreement demonstrated the potential application of laser-basedmore » Coulomb explosion in imaging transient molecular structure, particularly for floppy van der Waals complexes, whose structures remain difficult to be determined by conventional spectroscopic methods.« less

  15. Gradual Diffusion and Punctuated Phase Space Density Enhancements of Highly Relativistic Electrons: Van Allen Probes Observations

    NASA Technical Reports Server (NTRS)

    Baker, D. N.; Jaynes, A. N.; Li, X.; Henderson, M. G.; Kanekal, S. G.; Reeves, G. D.; Spence, H. E.; Claudepierre, S. G.; Fennell, J. F.; Hudson, M. K.

    2014-01-01

    The dual-spacecraft Van Allen Probes mission has provided a new window into mega electron volt (MeV) particle dynamics in the Earth's radiation belts. Observations (up to E (is) approximately 10MeV) show clearly the behavior of the outer electron radiation belt at different timescales: months-long periods of gradual inward radial diffusive transport and weak loss being punctuated by dramatic flux changes driven by strong solar wind transient events. We present analysis of multi-MeV electron flux and phase space density (PSD) changes during March 2013 in the context of the first year of Van Allen Probes operation. This March period demonstrates the classic signatures both of inward radial diffusive energization and abrupt localized acceleration deep within the outer Van Allen zone (L (is) approximately 4.0 +/- 0.5). This reveals graphically that both 'competing' mechanisms of multi-MeV electron energization are at play in the radiation belts, often acting almost concurrently or at least in rapid succession.

  16. Binding and Diffusion of Lithium in Graphite: Quantum Monte Carlo Benchmarks and Validation of van der Waals Density Functional Methods

    SciTech Connect

    Ganesh, P.; Kim, Jeongnim; Park, Changwon

    2014-11-03

    In highly accurate diffusion quantum Monte Carlo (QMC) studies of the adsorption and diffusion of atomic lithium in AA-stacked graphite are compared with van der Waals-including density functional theory (DFT) calculations. Predicted QMC lattice constants for pure AA graphite agree with experiment. Pure AA-stacked graphite is shown to challenge many van der Waals methods even when they are accurate for conventional AB graphite. Moreover, the highest overall DFT accuracy, considering pure AA-stacked graphite as well as lithium binding and diffusion, is obtained by the self-consistent van der Waals functional vdW-DF2, although errors in binding energies remain. Empirical approaches based onmore » point charges such as DFT-D are inaccurate unless the local charge transfer is assessed. Our results demonstrate that the lithium carbon system requires a simultaneous highly accurate description of both charge transfer and van der Waals interactions, favoring self-consistent approaches.« less

  17. Depiction of a 17th-Century Tooth Extraction: A Drawing by Adriaen Pietersz van de Venne (Dutch, 1589-1662).

    PubMed

    Chernin, David A

    2017-01-01

    A prolific and inventive painter, draftsman, and poet, Adriaen Pietersz van de Venne was born in Delft in 1589. His wealthy parents had fled from Protestant persecution in the Southern (Spanish) Netherlands during the 1580s. Van de Venne was educated in Leiden, where he became part of the vibrant political and intellectual community around the University. He settled in Middleburg, in Zeeland, by 1614; his earliest dated paintings are also from this year. In 1625, van de Venne moved to The Hague, where he remained until his dealth. He executed several commissions for the Dutch stadholder Frederik Hendrik, was repeatedly elected dean of the guild of St. Luke, and in 1656 was one of the founding members of The Hague's painter's guild, "Pictura schilders confrerie." Van de Venne painted histories, portraits, and genre scenes; from 1618, he was also active as a printmaker and book illustrator, notably for the popular poet Jacob Cats. His literary accomplishments included satire and political propaganda, as well as several books of poetry. Copyright American Academy of the History of Dentistry.

  18. Two dimensional graphene nanogenerator by coulomb dragging: Moving van der Waals heterostructure

    SciTech Connect

    Zhong, Huikai; Li, Xiaoqiang; Wu, Zhiqian

    2015-06-15

    Harvesting energy from environment is the current focus of scientific community. Here, we demonstrate a graphene nanogenerator, which is based on moving van der Waals heterostructure formed between graphene and two dimensional (2D) graphene oxide (GO). This nanogenerator can convert mechanical energy into electricity with a voltage output of around 10 mV. Systematic experiments reveal the generated electricity originates from the coulomb interaction induced momentum transfer between 2D GO and holes in graphene. 2D boron nitride was also demonstrated to be effective in the framework of moving van der Waals heterostructure nanogenerator. This investigation of nanogenerator based on the interaction betweenmore » 2D macromolecule materials will be important to understand the origin of the flow-induced potential in nanomaterials and may have great potential in practical applications.« less

  19. Measured and Modelled Tidal Circulation Under Ice Covered Van Mijenforden

    NASA Astrophysics Data System (ADS)

    Nilsen, F.

    The observation and model area Van Mijenfjorden is situated at the west coast of Spits- bergen. An area of 533 km2 makes it the second largest fjord on Spitsbergen and the distance from the head to the mouth of the fjord is approximately 70 km. An 8.5km long and 1km wide island, Akseløya, is lying across the fjord mouth and blocking exchanges between the fjord and the coastal water masses outside. The sound Aksel- sundet on the northern side of the island is 1km wide and has a sill at 34m depth. On the southern side an islet, Mariaholmen, is between two sounds that are 200m wide and 2m deep, and 500m wide and 12m deep. Strong tidal currents exist in these sounds. Van Mijenfjorden has special ice conditions in that Akseløya almost closes the fjord, and comparatively little ice comes in from west. On the other hand, there are periods with fast ice in the fjord inside Akseløya longer than in other places, as the sea waves have little chance to break up fast ice here, or delay ice formation in autumn/winter. Van Mijenfjorden is often separated into two basins by a sill at 30m depth. The inner basin is typical 5km wide and has a maximum depth of 80m, while the outer basin is on average 10 km wide and has a maximum depth of 115m. Hydrographic measurements have been conducted since 1958 and up to the present. Through the last decade, The University Courses on Svalbard (UNIS) has used this fjord as a laboratory for their student excursions, in connection to courses in air-ice- ocean interaction and master programs, and build up an oceanographic data base. In this work, focus is put on the wintertime situation and the circulation under an ice covered fjord. Measurements show a mean cyclonic circulation pattern in the outer basin with tidal oscillation (mainly M2) superposed on this mean vector. A three- dimensional sigma layered numerical model called Bergen Ocean Model (BOM) was used to simulate the circulation in Van Mijenfjorden with only tidal forcing. The four most

  20. First NATO/SIBCA Exercise in Sampling of Chemical Warfare Agents (Eerste NATO/SIBCA-oefening in monstername van chemische strijdmiddelen).

    DTIC Science & Technology

    1998-01-01

    TNO-rapport PML1997-A81 Eerste NATO/SIBCA-oefening in monster- name van chemische strijdmiddelen TNO Prins Maurits Laboratorium Lange Kleiweg...27 Aantal pagina’s : 53 (incl. bijlagen, excl. RDP & distributielijst) Aantal bijlagen : 4 TNO Prins Maurits Laboratorium is onderdeel...van de hoofdgroep TNO Defensieonderzoek waartoe verder behoren: TNO Fysisch en Elektronisch Laboratorium TNO Technische Menskunde Nederlandse

  1. Role of the transmembrane domain of the VanT serine racemase in resistance to vancomycin in Enterococcus gallinarum BM4174.

    PubMed

    Arias, C A; Peña, J; Panesso, D; Reynolds, P

    2003-03-01

    Enterococcus gallinarum BM4175 (a vancomycin-susceptible derivative of BM4174 obtained by insertional inactivation of vanC-1) was transformed with plasmid constructs pCA10 (containing the genes necessary for resistance, vanC-1-XYc-T), pJP1 (with a fragment lacking the DNA encoding the transmembrane region of VanT, -vanC-1-XYc-T((Delta))(2-322)-) and with plasmids containing fragments encoding either the transmembrane (mvanT(1-322)) or racemase (svanT(323-698)) domains of VanT under the control of a constitutive promoter. Accumulated peptidoglycan precursors were measured in all strains in the presence of L-Ser, D-Ser (50 mM) or in the absence of any growth supplement. Uptake of 0.1 mM L-[(14)C]serine was also determined in BM4174, BM4175 and BM4175/pCA10. Vancomycin resistance was restored in BM4175 transformed with pCA10(C-1-XYc-T), and the profile of peptidoglycan precursors was similar to wild-type E. gallinarum BM4174. Transformation of E. gallinarum BM4175 with plasmid pJP1(vanC-1-XYc-T((Delta))(2-322)) resulted in: (i) vancomycin MICs remaining within susceptible levels (< or =4 mg/L) in the absence of any growth supplement, but increasing to 8 mg/L when either L-Ser or D-Ser was added to the medium; and (ii) the relative amounts of accumulated UDP-MurNAc-pentapeptide[D-Ser] and tetrapeptide precursors decreasing substantially compared with BM4175/pCA10 and BM4174. The effect on the appearance of tetrapeptide appeared to be host dependent, since a substantial amount was present when the same plasmid construct pJP1(vanC-1-XYc-T((Delta))(2-322)) was electroporated into Enterococcus faecalis JH2-2. The uptake of L-[(14)C]Ser at 240 s was decreased by approximately 40% in BM4175 compared with BM4174. Plasmid pCA10(C-1-XY(C)-T) restored uptake of L-[(14)C]Ser at 180 and 240 s in BM4175. The results suggest that the transmembrane domain of VanT is likely to be involved in the transport of L-Ser, and that in its absence the resistance phenotype is compromised.

  2. Eighteen-Month Final Evaluation of UPS Second Generation Diesel Hybrid-Electric Delivery Vans

    SciTech Connect

    Lammert, M.; Walkowicz, K.

    2012-09-01

    A parallel hybrid-electric diesel delivery van propulsion system was evaluated at a UPS facility in Minneapolis using on-vehicle data logging, fueling, and maintenance records. Route and drive cycle analysis showed different duty cycles for hybrid vs. conventional delivery vans; routes were switched between the study groups to provide a valid comparison. The hybrids demonstrated greater advantage on the more urban routes; the initial conventional vans' routes had less dense delivery zones. The fuel economy of the hybrids on the original conventional group?s routes was 10.4 mpg vs. 9.2 mpg for the conventional group on those routes a year earlier. Themore » hybrid group's fuel economy on the original hybrid route assignments was 9.4 mpg vs. 7.9 mpg for the conventional group on those routes a year later. There was no statistically significant difference in total maintenance cost per mile or for the vehicle total cost of operation per mile. Propulsion-related maintenance cost per mile was 77% higher for the hybrids, but only 52% more on a cost-per-delivery-day basis. Laboratory dynamometer testing demonstrated 13%-36% hybrid fuel economy improvement, depending on duty cycle, and up to a 45% improvement in ton-mi/gal. NOx emissions increased 21%-49% for the hybrids in laboratory testing.« less

  3. Antiferromagnetism in the van der Waals layered spin-lozenge semiconductor CrTe 3

    DOE PAGES

    McGuire, Michael A.; Garlea, V. Ovidiu; KC, Santosh; ...

    2017-04-14

    We have investigated the crystallographic, magnetic, and transport properties of the van der Waals bonded, layered compound CrTe 3 on single-crystal and polycrystalline materials. Furthermore, the crystal structure contains layers made up of lozenge-shaped Cr 4 tetramers. Electrical resistivity measurements show the crystals to be semiconducting, with a temperature dependence consistent with a band gap of 0.3 eV. The magnetic susceptibility exhibits a broad maximum near 300 K characteristic of low dimensional magnetic systems. Weak anomalies are observed in the susceptibility and heat capacity near 55 K, and single-crystal neutron diffraction reveals the onset of long-range antiferromagnetic order at thismore » temperature. Strongly dispersive spin waves are observed in the ordered state. Significant magnetoelastic coupling is indicated by the anomalous temperature dependence of the lattice parameters and is evident in structural optimization in van der Waals density functional theory calculations for different magnetic configurations. The cleavability of the compound is apparent from its handling and is confirmed by first-principles calculations, which predict a cleavage energy 0.5 J / m 2 , similar to graphite. Based on our results, CrTe 3 is identified as a promising compound for studies of low dimensional magnetism in bulk crystals as well as magnetic order in monolayer materials and van der Waals heterostructures.« less

  4. Antiferromagnetism in the van der Waals layered spin-lozenge semiconductor CrTe 3

    SciTech Connect

    McGuire, Michael A.; Garlea, V. Ovidiu; KC, Santosh

    We have investigated the crystallographic, magnetic, and transport properties of the van der Waals bonded, layered compound CrTe 3 on single-crystal and polycrystalline materials. Furthermore, the crystal structure contains layers made up of lozenge-shaped Cr 4 tetramers. Electrical resistivity measurements show the crystals to be semiconducting, with a temperature dependence consistent with a band gap of 0.3 eV. The magnetic susceptibility exhibits a broad maximum near 300 K characteristic of low dimensional magnetic systems. Weak anomalies are observed in the susceptibility and heat capacity near 55 K, and single-crystal neutron diffraction reveals the onset of long-range antiferromagnetic order at thismore » temperature. Strongly dispersive spin waves are observed in the ordered state. Significant magnetoelastic coupling is indicated by the anomalous temperature dependence of the lattice parameters and is evident in structural optimization in van der Waals density functional theory calculations for different magnetic configurations. The cleavability of the compound is apparent from its handling and is confirmed by first-principles calculations, which predict a cleavage energy 0.5 J / m 2 , similar to graphite. Based on our results, CrTe 3 is identified as a promising compound for studies of low dimensional magnetism in bulk crystals as well as magnetic order in monolayer materials and van der Waals heterostructures.« less

  5. van der Waals-Tonks-type equations of state for hard-hypersphere fluids in four and five dimensions

    NASA Astrophysics Data System (ADS)

    Wang, Xian-Zhi

    2004-04-01

    Recently, we developed accurate van der Waals-Tonks-type equations of state for hard-disk and hard-sphere fluids by using the known virial coefficients. In this paper, we derive the van der Waals-Tonks-type equations of state. We further apply these equations of state to hard-hypersphere fluids in four and five dimensions. In the low-density fluid regime, these equations of state are in good agreement with the simulation results and existing equations of state.

  6. Fostering Students' Creativity through Van Hiele's 5 Phase-Based Tangram Activities

    ERIC Educational Resources Information Center

    Siew, Nyet Moi; Chong, Chin Lu

    2014-01-01

    The aim of this study was to determine whether Van Hiele's 5 phase-based tangrams activities could help to foster creativity among Grade Three primary school students. Students' creativity was investigated in terms of Torrance's Figural Test of creative thinking: Fluency, Originality, Elaboration, Abstractness of title, and Resistance to a…

  7. MTR BASEMENT. WORKERS (DON ALVORD AND CYRIL VAN ORDEN OF ...

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

    MTR BASEMENT. WORKERS (DON ALVORD AND CYRIL VAN ORDEN OF PHILLIPS PETROLEUM CO.) POSE FOR GAMMA IRRADIATION EXPERIMENT IN MTR CANAL. CANS OF FOOD WILL BE LOWERED TO CANAL BOTTOM, WHERE SPENT MTR FUEL ELEMENTS EMIT GAMMA RADIATION. INL NEGATIVE NO. 11746. Unknown Photographer, 8/20/1954 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

  8. Paint it Black: Using Change-Point Analysis to Investigate Increasing Vulnerability to Depression towards the End of Vincent van Gogh’s Life

    PubMed Central

    van Emmerik, Arnold A. P.; Hamaker, Ellen L.

    2017-01-01

    This study investigated whether Vincent van Gogh became increasingly self-focused—and thus vulnerable to depression—towards the end of his life, through a quantitative analysis of his written pronoun use over time. A change-point analysis was conducted on the time series formed by the pronoun use in Van Gogh’s letters. We used time as a predictor to see whether there was evidence for increased self-focus towards the end of Van Gogh’s life, and we compared this to the pattern in the letters written before his move to Arles. Specifically, we examined Van Gogh’s use of first person singular pronouns (FPSP) and first person plural pronouns (FPPP) in the 415 letters he wrote while working as an artist before his move to Arles, and in the next 248 letters he wrote after his move to Arles until his death in Auvers-sur-Oise. During the latter period, Van Gogh’s use of FPSP showed an annual increase of 0.68% (SE = 0.15, p < 0.001) and his use of FPPP showed an annual decrease of 0.23% (SE = 0.04, p < 0.001), indicating increasing self-focus and vulnerability to depression. This trend differed from Van Gogh’s pronoun use in the former period (which showed no significant trend in FPSP, and an annual increase of FPPP of 0.03%, SE = 0.02, p = 0.04). This study suggests that Van Gogh’s death was preceded by a gradually increasing self-focus and vulnerability to depression. It also illustrates how existing methods (i.e., quantitative linguistic analysis and change-point analysis) can be combined to study specific research questions in innovative ways. PMID:28869542

  9. Back to the future of soil metagenomics

    DOE PAGES

    Nesme, Joseph; Achouak, Wafa; Agathos, Spiros N.; ...

    2016-02-10

    Here, direct extraction and characterization of microbial community DNA through PCR amplicon surveys and metagenomics has revolutionized the study of environmental microbiology and microbial ecology. In particular, metagenomic analysis of nucleic acids provides direct access to the genomes of the “uncultivated majority.” Accelerated by advances in sequencing technology, microbiologists have discovered more novel phyla, classes, genera, and genes from microorganisms in the first decade and a half of the twenty-first century than since these “many very little living animalcules” were first discovered by van Leeuwenhoek (Table 1). The unsurpassed diversity of soils promises continued exploration of a range of industrial,more » agricultural, and environmental functions. The ability to explore soil microbial communities with increasing capacity offers the highest promise for answering many outstanding who, what, where, when, why, and with whom questions such as: Which microorganisms are linked to which soil habitats? How do microbial abundances change with changing edaphic conditions? How do microbial assemblages interact and influence one another synergistically or antagonistically? What is the full extent of soil microbial diversity, both functionally and phylogenetically? What are the dynamics of microbial communities in space and time? How sensitive are microbial communities to a changing climate? What is the role of horizontal gene transfer in the stability of microbial communities? Do highly diverse microbial communities confer resistance and resilience in soils?« less

  10. Back to the future of soil metagenomics

    SciTech Connect

    Nesme, Joseph; Achouak, Wafa; Agathos, Spiros N.

    Here, direct extraction and characterization of microbial community DNA through PCR amplicon surveys and metagenomics has revolutionized the study of environmental microbiology and microbial ecology. In particular, metagenomic analysis of nucleic acids provides direct access to the genomes of the “uncultivated majority.” Accelerated by advances in sequencing technology, microbiologists have discovered more novel phyla, classes, genera, and genes from microorganisms in the first decade and a half of the twenty-first century than since these “many very little living animalcules” were first discovered by van Leeuwenhoek (Table 1). The unsurpassed diversity of soils promises continued exploration of a range of industrial,more » agricultural, and environmental functions. The ability to explore soil microbial communities with increasing capacity offers the highest promise for answering many outstanding who, what, where, when, why, and with whom questions such as: Which microorganisms are linked to which soil habitats? How do microbial abundances change with changing edaphic conditions? How do microbial assemblages interact and influence one another synergistically or antagonistically? What is the full extent of soil microbial diversity, both functionally and phylogenetically? What are the dynamics of microbial communities in space and time? How sensitive are microbial communities to a changing climate? What is the role of horizontal gene transfer in the stability of microbial communities? Do highly diverse microbial communities confer resistance and resilience in soils?« less

  11. Synergisms between microbial pathogens in plant disease complexes: a growing trend

    PubMed Central

    Lamichhane, Jay Ram; Venturi, Vittorio

    2015-01-01

    Plant diseases are often thought to be caused by one species or even by a specific strain. Microbes in nature, however, mostly occur as part of complex communities and this has been noted since the time of van Leeuwenhoek. Interestingly, most laboratory studies focus on single microbial strains grown in pure culture; we were therefore unaware of possible interspecies and/or inter-kingdom interactions of pathogenic microbes in the wild. In human and animal infections, it is now being recognized that many diseases are the result of multispecies synergistic interactions. This increases the complexity of the disease and has to be taken into consideration in the development of more effective control measures. On the other hand, there are only a few reports of synergistic pathogen–pathogen interactions in plant diseases and the mechanisms of interactions are currently unknown. Here we review some of these reports of synergism between different plant pathogens and their possible implications in crop health. Finally, we briefly highlight the recent technological advances in diagnostics as these are beginning to provide important insights into the microbial communities associated with complex plant diseases. These examples of synergistic interactions of plant pathogens that lead to disease complexes might prove to be more common than expected and understanding the underlying mechanisms might have important implications in plant disease epidemiology and management. PMID:26074945

  12. Development of a Hands-On Survey Course in the Physics of Living Systems

    NASA Astrophysics Data System (ADS)

    Matthews, Megan; Goldman, Daniel I.

    Due to the widespread availability and technological capabilities of modern smartphones, many biophysical systems can be investigated using easily accessible, low-cost, and/or ``homemade'' equipment. Our survey course is structured to provide students with an overview of research in the physics of living systems, emphasizing the interplay between measurement, mechanism, and modeling required to understand principles at the intersection of physics and biology. The course proceeds through seven modules each consisting of one week of lectures and one week of hands-on experiments, called ``microlabs''. Using smartphones, Arduinos, and 3D printed materials students create their own laboratory equipment, including a 150X van Leeuwenhoek microscope, a shaking incubator, and an oscilloscope, and then use them to study biological systems ranging in length scales from nanometers to meters. These systems include population dynamics of rotifer/algae cultures, experimental evolution of multicellularity in budding yeast, and the bio- & neuromechanics involved in animal locomotion, among others. In each module, students are introduced to fundamental biological and physical concepts as well as theoretical and computational tools (nonlinear dynamics, molecular dynamics simulation, and statistical mechanics). At the end of the course, students apply these concepts and tools to the creation of their own microlab that integrates hands-on experimentation and modeling in the study of their chosen biophysical system.

  13. Sperm Parameters: Paradigmatic Index of Good Health and Longevity

    PubMed Central

    Omu, Alexander E.

    2013-01-01

    Since the discovery of spermatozoon by Anton van Leeuwenhoek in 1677, there has been an ever increasing understanding of its role in reproduction. Many factors adversely affect sperm quality, including varicocele, accessory gland infection, immunological factors, congenital abnormalities, and iatrogenic systemic and endocrine causes, such as diabetes mellitus, obesity, metabolic syndrome, and smoking. The mechanisms responsible for the association between poor sperm parameters and ill health may include oxidative stress, low-grade inflammation, low testosterone, and low sex-hormone-binding globulin. Oxidative stress in the testicular microenvironment may result in decreased spermatogenesis and sperm DNA damage, loss of sperm motility, and abnormal sperm morphology. Low testosterone caused by advanced age, visceral obesity, and inflammation is associated with the development of cardiovascular disease. Hence, semen analysis has an important role in the routine evaluation of idiopathic male infertility, usually manifested as low sperm counts, impaired sperm motility, or absence of sperm, and remains the most common single diagnostic tool. Several studies have shown an inverse relationship between semen quality and medical disorders. This review elucidates the effect of medical disorders and social habits on sperm quality, the mechanisms that are involved in the impairment of sperm quality, and whether or not sperm quality can be used as an index of good health and longevity in a man. PMID:24051979

  14. Fifteen-passenger vans and other transportation options: a comparison of driver, vehicle, and crash characteristics.

    PubMed

    Potter, Tom; Dubois, Sacha; Haras, Kathy; Bédard, Michel

    2013-01-01

    Fifteen-passenger vans (15-PVs) are a convenient and economical way to transport small groups of people and many educational, community, and health organizations utilize them. Given recent tragic crashes involving 15-PVs, many organizations are reconsidering their use. The goal of this study was to examine driver, vehicle, and crash characteristics of fatal 15-PV collisions over the past 2 decades in comparison to 3 other common vehicle classes. We used data from the Fatality Analysis Reporting System (years 1991-2008). Driver, vehicle, and crash characteristics were compared by vehicle classes (15-PV, cars, minivans, and intercity buses) using proportions along with odds ratios (using cars as the reference category) for dichotomous variables and means and mean differences for continuous variables. Logistic regression and analysis of variance were used to statistically compare odds and means, respectively. The odds and absolute risk of a first, subsequent, and either rollover by vehicle type and occupancy rate were also examined. Odds and absolute risk of a rollover event by occupancy rate were calculated. Compared to car drivers, van drivers typically had a better past 3-year driving record. Van drivers performed significantly fewer actions suggesting aggressive driving (e.g., speeding). However, the proportion of van drivers who were deemed to have followed improperly or to have overcorrected was greater. A vehicle rollover was cited almost twice as frequently in van crashes compared to other passenger vehicles. Of the 4 vehicle types studied, all were more likely to rollover as their occupancy rates increased. Fully loaded 15-PVs had almost 13 times the odds of rollover compared to fully loaded cars. Minivans when full (7 occupants), often seen as the replacement for 15-PVs, were found to have over 3.5 times the odds of rollover of fully loaded cars. Drivers need to be aware that as occupancy rates of the vehicles they drive rise so does the risk of rollover and

  15. Results of baseline tests of the EVA metro sedan, citi-car, jet industries electra-van, CDA town car, and OTIS P-500 van

    SciTech Connect

    Stenger, F.J.; Bozek, J.M.; Soltis, R.F.

    1976-10-01

    Five electric vehicles were tested at vehicle test tracks using the SAE. The tests provide range data at steady speeds and for several driving cycles. Most tests were conducted with lead-acid traction batteries. The Otis Van and the Copper Electric Town Car were also tested with lead-acid and nickel-zinc batteries. The tests showed a range increase of from 82 to 101 percent depending on vehicle, speed, and test cycle.

  16. Results of baseline tests of the EVA Metro sedan, Citi-car, Jet Industries Electra-van, CDA town car, and Otis P-500 van

    NASA Technical Reports Server (NTRS)

    Stenger, F. J.; Bozek, J. M.; Soltis, R. F.

    1976-01-01

    Five electric vehicles were tested at vehicle test tracks using the SAE. The tests provide range data at steady speeds and for several driving cycles. Most tests were conducted with lead-acid traction batteries. The Otis Van and the Copper Electric Town Car were also tested with lead-acid and nickel-zinc batteries. The tests showed a range increase of from 82 to 101 percent depending on vehicle, speed, and test cycle.

  17. Engineering Low Dimensional Materials with van der Waals Interaction

    NASA Astrophysics Data System (ADS)

    Jin, Chenhao

    Two-dimensional van der Waals materials grow into a hot and big field in condensed matter physics in the past decade. One particularly intriguing thing is the possibility to stack different layers together as one wish, like playing a Lego game, which can create artificial structures that do not exist in nature. These new structures can enable rich new physics from interlayer interaction: The interaction is strong, because in low-dimension materials electrons are exposed to the interface and are susceptible to other layers; and the screening of interaction is less prominent. The consequence is rich, not only from the extensive list of two-dimensional materials available nowadays, but also from the freedom of interlayer configuration, such as displacement and twist angle, which creates a gigantic parameter space to play with. On the other hand, however, the huge parameter space sometimes can make it challenging to describe consistently with a single picture. For example, the large periodicity or even incommensurability in van der Waals systems creates difficulty in using periodic boundary condition. Worse still, the huge superlattice unit cell and overwhelming computational efforts involved to some extent prevent the establishment of a simple physical picture to understand the evolution of system properties in the parameter space of interlayer configuration. In the first part of the dissertation, I will focus on classification of the huge parameter space into subspaces, and introduce suitable theoretical approaches for each subspace. For each approach, I will discuss its validity, limitation, general solution, as well as a specific example of application demonstrating how one can obtain the most important effects of interlayer interaction with little computation efforts. Combining all the approaches introduced will provide an analytic solution to cover majority of the parameter space, which will be very helpful in understanding the intuitive physical picture behind

  18. Properties of real metallic surfaces: Effects of density functional semilocality and van der Waals nonlocality

    PubMed Central

    Patra, Abhirup; Bates, Jefferson E.; Sun, Jianwei; Perdew, John P.

    2017-01-01

    We have computed the surface energies, work functions, and interlayer surface relaxations of clean (111), (100), and (110) surfaces of Al, Cu, Ru, Rh, Pd, Ag, Pt, and Au. We interpret the surface energy from liquid metal measurements as the mean of the solid-state surface energies over these three lowest-index crystal faces. We compare experimental (and random phase approximation) reference values to those of a family of nonempirical semilocal density functionals, from the basic local density approximation (LDA) to our most advanced general purpose meta-generalized gradient approximation, strongly constrained and appropriately normed (SCAN). The closest agreement is achieved by the simplest density functional LDA, and by the most sophisticated one, SCAN+rVV10 (Vydrov–Van Voorhis 2010). The long-range van der Waals interaction, incorporated through rVV10, increases the surface energies by about 10%, and increases the work functions by about 3%. LDA works for metal surfaces through two known error cancellations. The Perdew–Burke–Ernzerhof generalized gradient approximation tends to underestimate both surface energies (by about 24%) and work functions (by about 4%), yielding the least-accurate results. The amount by which a functional underestimates these surface properties correlates with the extent to which it neglects van der Waals attraction at intermediate and long range. Qualitative arguments are given for the signs of the van der Waals contributions to the surface energy and work function. A standard expression for the work function in Kohn–Sham (KS) theory is shown to be valid in generalized KS theory. Interlayer relaxations from different functionals are in reasonable agreement with one another, and usually with experiment. PMID:29042509

  19. Promoting Preservice Teacher Reflectivity: Van Manen May Represent a Viable Model

    ERIC Educational Resources Information Center

    Ballard, Kristy K.; McBride, Ron

    2010-01-01

    From Dewey (1933) to present, reflectivity is an important component of teacher education. Little information exists that specifically addresses when changes in reflectivity might occur. Therefore, the purpose of this study was: (a) to apply Van Manen's model to outcomes to examine levels of, and changes in, reflectivity and (b) to verify the…

  20. Prediction of intrinsic two-dimensional ferroelectrics in In2Se3 and other III2-VI3 van der Waals materials.

    PubMed

    Ding, Wenjun; Zhu, Jianbao; Wang, Zhe; Gao, Yanfei; Xiao, Di; Gu, Yi; Zhang, Zhenyu; Zhu, Wenguang

    2017-04-07

    Interest in two-dimensional (2D) van der Waals materials has grown rapidly across multiple scientific and engineering disciplines in recent years. However, ferroelectricity, the presence of a spontaneous electric polarization, which is important in many practical applications, has rarely been reported in such materials so far. Here we employ first-principles calculations to discover a branch of the 2D materials family, based on In 2 Se 3 and other III 2 -VI 3 van der Waals materials, that exhibits room-temperature ferroelectricity with reversible spontaneous electric polarization in both out-of-plane and in-plane orientations. The device potential of these 2D ferroelectric materials is further demonstrated using the examples of van der Waals heterostructures of In 2 Se 3 /graphene, exhibiting a tunable Schottky barrier, and In 2 Se 3 /WSe 2 , showing a significant band gap reduction in the combined system. These findings promise to substantially broaden the tunability of van der Waals heterostructures for a wide range of applications.

  1. Prediction of intrinsic two-dimensional ferroelectrics in In2Se3 and other III2-VI3 van der Waals materials

    PubMed Central

    Ding, Wenjun; Zhu, Jianbao; Wang, Zhe; Gao, Yanfei; Xiao, Di; Gu, Yi; Zhang, Zhenyu; Zhu, Wenguang

    2017-01-01

    Interest in two-dimensional (2D) van der Waals materials has grown rapidly across multiple scientific and engineering disciplines in recent years. However, ferroelectricity, the presence of a spontaneous electric polarization, which is important in many practical applications, has rarely been reported in such materials so far. Here we employ first-principles calculations to discover a branch of the 2D materials family, based on In2Se3 and other III2-VI3 van der Waals materials, that exhibits room-temperature ferroelectricity with reversible spontaneous electric polarization in both out-of-plane and in-plane orientations. The device potential of these 2D ferroelectric materials is further demonstrated using the examples of van der Waals heterostructures of In2Se3/graphene, exhibiting a tunable Schottky barrier, and In2Se3/WSe2, showing a significant band gap reduction in the combined system. These findings promise to substantially broaden the tunability of van der Waals heterostructures for a wide range of applications. PMID:28387225

  2. Prediction of intrinsic two-dimensional ferroelectrics in In2Se3 and other III2-VI3 van der Waals materials

    NASA Astrophysics Data System (ADS)

    Ding, Wenjun; Zhu, Jianbao; Wang, Zhe; Gao, Yanfei; Xiao, Di; Gu, Yi; Zhang, Zhenyu; Zhu, Wenguang

    2017-04-01

    Interest in two-dimensional (2D) van der Waals materials has grown rapidly across multiple scientific and engineering disciplines in recent years. However, ferroelectricity, the presence of a spontaneous electric polarization, which is important in many practical applications, has rarely been reported in such materials so far. Here we employ first-principles calculations to discover a branch of the 2D materials family, based on In2Se3 and other III2-VI3 van der Waals materials, that exhibits room-temperature ferroelectricity with reversible spontaneous electric polarization in both out-of-plane and in-plane orientations. The device potential of these 2D ferroelectric materials is further demonstrated using the examples of van der Waals heterostructures of In2Se3/graphene, exhibiting a tunable Schottky barrier, and In2Se3/WSe2, showing a significant band gap reduction in the combined system. These findings promise to substantially broaden the tunability of van der Waals heterostructures for a wide range of applications.

  3. van der Waals criticality in AdS black holes: A phenomenological study

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Krishnakanta; Majhi, Bibhas Ranjan; Samanta, Saurav

    2017-10-01

    Anti-de Sitter black holes exhibit van der Waals-type phase transition. In the extended phase-space formalism, the critical exponents for any spacetime metric are identical to the standard ones. Motivated by this fact, we give a general expression for the Helmholtz free energy near the critical point, which correctly reproduces these exponents. The idea is similar to the Landau model, which gives a phenomenological description of the usual second-order phase transition. Here, two main inputs are taken into account for the analysis: (a) black holes should have van der Waals-like isotherms, and (b) free energy can be expressed solely as a function of thermodynamic volume and horizon temperature. Resulting analysis shows that the form of Helmholtz free energy correctly encapsulates the features of the Landau function. We also discuss the isolated critical point accompanied by nonstandard values of critical exponents. The whole formalism is then extended to two other criticalities, namely, Y -X and T -S (based on the standard; i.e., nonextended phase space), where X and Y are generalized force and displacement, whereas T and S are the horizon temperature and entropy. We observe that in the former case Gibbs free energy plays the role of Landau function, whereas in the later case, that role is played by the internal energy (here, it is the black hole mass). Our analysis shows that, although the existence of a van der Waals phase transition depends on the explicit form of the black hole metric, the values of the critical exponents are universal in nature.

  4. [Preserving life and limb on the stage of death: the Dance of Death by Dr Salomon van Rusting].

    PubMed

    Dreier, Rolf P; Mackenbach, Johan P

    2012-01-01

    Salomon van Rusting was a medical doctor from Amsterdam who lived and worked around the early 1700 s. He wrote one of the few Dutch Death Dances, naming it 'Het Schouw-Tooneel des Doods'. A Death Dance was an artistic expression of human death popular in the Late Middle Ages. The traditional Death Dance invited acknowledgement of the vanity of worldly existence ('memento mori') by portraying human subjects' encounters with 'Death'. This paper describes the context in which Van Rusting's work arose and briefly characterizes its highly original and, for the most part, rather burlesque nature. In contrast to other Death Dances, Van Rusting's work does not represent medicine as being powerless in the face of death. His work strikes us as having almost modern confidence in our own ability to avoid an untimely death by living sensibly.

  5. Electric-field switching of two-dimensional van der Waals magnets

    NASA Astrophysics Data System (ADS)

    Jiang, Shengwei; Shan, Jie; Mak, Kin Fai

    2018-05-01

    Controlling magnetism by purely electrical means is a key challenge to better information technology1. A variety of material systems, including ferromagnetic (FM) metals2-4, FM semiconductors5, multiferroics6-8 and magnetoelectric (ME) materials9,10, have been explored for the electric-field control of magnetism. The recent discovery of two-dimensional (2D) van der Waals magnets11,12 has opened a new door for the electrical control of magnetism at the nanometre scale through a van der Waals heterostructure device platform13. Here we demonstrate the control of magnetism in bilayer CrI3, an antiferromagnetic (AFM) semiconductor in its ground state12, by the application of small gate voltages in field-effect devices and the detection of magnetization using magnetic circular dichroism (MCD) microscopy. The applied electric field creates an interlayer potential difference, which results in a large linear ME effect, whose sign depends on the interlayer AFM order. We also achieve a complete and reversible electrical switching between the interlayer AFM and FM states in the vicinity of the interlayer spin-flip transition. The effect originates from the electric-field dependence of the interlayer exchange bias.

  6. Combination Rules for Morse-Based van der Waals Force Fields.

    PubMed

    Yang, Li; Sun, Lei; Deng, Wei-Qiao

    2018-02-15

    In traditional force fields (FFs), van der Waals interactions have been usually described by the Lennard-Jones potentials. Conventional combination rules for the parameters of van der Waals (VDW) cross-termed interactions were developed for the Lennard-Jones based FFs. Here, we report that the Morse potentials were a better function to describe VDW interactions calculated by highly precise quantum mechanics methods. A new set of combination rules was developed for Morse-based FFs, in which VDW interactions were described by Morse potentials. The new set of combination rules has been verified by comparing the second virial coefficients of 11 noble gas mixtures. For all of the mixed binaries considered in this work, the combination rules work very well and are superior to all three other existing sets of combination rules reported in the literature. We further used the Morse-based FF by using the combination rules to simulate the adsorption isotherms of CH 4 at 298 K in four covalent-organic frameworks (COFs). The overall agreement is great, which supports the further applications of this new set of combination rules in more realistic simulation systems.

  7. Hybrid, Gate-Tunable, van der Waals p–n Heterojunctions from Pentacene and MoS 2

    DOE PAGES

    Jariwala, Deep; Howell, Sarah L.; Chen, Kan-Sheng; ...

    2015-12-18

    The recent emergence of a wide variety of two-dimensional (2D) materials has created new opportunities for device concepts and applications. In particular, the availability of semiconducting transition metal dichalcogenides, in addition to semimetallic graphene and insulating boron nitride, has enabled the fabrication of “all 2D” van der Waals heterostructure devices. Furthermore, the concept of van der Waals heterostructures has the potential to be significantly broadened beyond layered solids. For example, molecular and polymeric organic solids, whose surface atoms possess saturated bonds, are also known to interact via van der Waals forces and thus offer an alternative for scalable integration withmore » 2D materials. Here, we demonstrate the integration of an organic small molecule p-type semiconductor, pentacene, with a 2D n-type semiconductor, MoS2. The resulting p–n heterojunction is gate-tunable and shows asymmetric control over the antiambipolar transfer characteristic. In addition, the pentacene/MoS2 heterojunction exhibits a photovoltaic effect attributable to type II band alignment, which suggests that MoS2 can function as an acceptor in hybrid solar cells.« less

  8. Hybrid, Gate-Tunable, van der Waals p–n Heterojunctions from Pentacene and MoS 2

    DOE PAGES

    Jariwala, Deep; Howell, Sarah L.; Chen, Kan -Sheng; ...

    2015-12-10

    Here, the recent emergence of a wide variety of two-dimensional (2D) materials has created new opportunities for device concepts and applications. In particular, the availability of semiconducting transition metal dichalcogenides, in addition to semimetallic graphene and insulating boron nitride, has enabled the fabrication of “all 2D” van der Waals heterostructure devices. Furthermore, the concept of van der Waals heterostructures has the potential to be significantly broadened beyond layered solids. For example, molecular and polymeric organic solids, whose surface atoms possess saturated bonds, are also known to interact via van der Waals forces and thus offer an alternative for scalable integrationmore » with 2D materials. Here, we demonstrate the integration of an organic small molecule p-type semiconductor, pentacene, with a 2D n-type semiconductor, MoS 2. The resulting p–n heterojunction is gate-tunable and shows asymmetric control over the antiambipolar transfer characteristic. In addition, the pentacene/MoS 2 heterojunction exhibits a photovoltaic effect attributable to type II band alignment, which suggests that MoS 2 can function as an acceptor in hybrid solar cells.« less

  9. Hybrid, Gate-Tunable, van der Waals p–n Heterojunctions from Pentacene and MoS 2

    SciTech Connect

    Jariwala, Deep; Howell, Sarah L.; Chen, Kan -Sheng

    Here, the recent emergence of a wide variety of two-dimensional (2D) materials has created new opportunities for device concepts and applications. In particular, the availability of semiconducting transition metal dichalcogenides, in addition to semimetallic graphene and insulating boron nitride, has enabled the fabrication of “all 2D” van der Waals heterostructure devices. Furthermore, the concept of van der Waals heterostructures has the potential to be significantly broadened beyond layered solids. For example, molecular and polymeric organic solids, whose surface atoms possess saturated bonds, are also known to interact via van der Waals forces and thus offer an alternative for scalable integrationmore » with 2D materials. Here, we demonstrate the integration of an organic small molecule p-type semiconductor, pentacene, with a 2D n-type semiconductor, MoS 2. The resulting p–n heterojunction is gate-tunable and shows asymmetric control over the antiambipolar transfer characteristic. In addition, the pentacene/MoS 2 heterojunction exhibits a photovoltaic effect attributable to type II band alignment, which suggests that MoS 2 can function as an acceptor in hybrid solar cells.« less

  10. Hysterical chorea: Report of an outbreak and movie documentation by Arthur Van Gehuchten (1861-1914).

    PubMed

    Giménez-Roldán, Santiago; Aubert, Geneviève

    2007-06-15

    Psychogenic movement disorders remain a frequent and important clinical problem. First described in the Middle Ages, the dancing mania is considered to be one form of mass hysteria characterized by outbreaks of collective movement disorders. Patients may exhibit a wide variety of movement and gait disturbances, including tremulousness, jerks, or convulsions, usually with a sudden onset. Arthur Van Gehuchten (1861-1914), a distinguished Belgian neuroanatomist and neurologist, reported an outbreak of sudden involuntary movements in 13 adolescent girls residing in an orphanage. The description is to be found in his book Les Maladies nerveuses, completed before 1914 and published posthumously in 1920. The chapter is illustrated with sequential photographs of a girl exhibiting a peculiar gait, which is descriptively referred to as "chorée salutatoire" (saluting chorea). The original film with these pictures has been retrieved and is presented here together with a very similar film excerpt also found in Van Gehuchten's film collection. Van Gehuchten's movie documentation of a psychogenic movement disorder--labeled chorea but which should probably be considered as dystonia according to contemporary classification--appears to be unique. This report illustrates the tremendous value of moving pictures in recording and analyzing movement disorders.

  11. Effects of van der Waals Force and Thermal Stresses on Pull-in Instability of Clamped Rectangular Microplates.

    PubMed

    Batra, Romesh C; Porfiri, Maurizio; Spinello, Davide

    2008-02-15

    We study the influence of von Karman nonlinearity, van der Waals force, and a athermal stresses on pull-in instability and small vibrations of electrostatically actuated mi-croplates. We use the Galerkin method to develop a tractable reduced-order model for elec-trostatically actuated clamped rectangular microplates in the presence of van der Waals forcesand thermal stresses. More specifically, we reduce the governing two-dimensional nonlineartransient boundary-value problem to a single nonlinear ordinary differential equation. For thestatic problem, the pull-in voltage and the pull-in displacement are determined by solving apair of nonlinear algebraic equations. The fundamental vibration frequency corresponding toa deflected configuration of the microplate is determined by solving a linear algebraic equa-tion. The proposed reduced-order model allows for accurately estimating the combined effectsof van der Waals force and thermal stresses on the pull-in voltage and the pull-in deflectionprofile with an extremely limited computational effort.

  12. Effects of van der Waals Force and Thermal Stresses on Pull-in Instability of Clamped Rectangular Microplates

    PubMed Central

    Batra, Romesh C.; Porfiri, Maurizio; Spinello, Davide

    2008-01-01

    We study the influence of von Kármán nonlinearity, van der Waals force, and thermal stresses on pull-in instability and small vibrations of electrostatically actuated microplates. We use the Galerkin method to develop a tractable reduced-order model for electrostatically actuated clamped rectangular microplates in the presence of van der Waals forces and thermal stresses. More specifically, we reduce the governing two-dimensional nonlinear transient boundary-value problem to a single nonlinear ordinary differential equation. For the static problem, the pull-in voltage and the pull-in displacement are determined by solving a pair of nonlinear algebraic equations. The fundamental vibration frequency corresponding to a deflected configuration of the microplate is determined by solving a linear algebraic equation. The proposed reduced-order model allows for accurately estimating the combined effects of van der Waals force and thermal stresses on the pull-in voltage and the pull-in deflection profile with an extremely limited computational effort. PMID:27879752

  13. Clinico-Microbiological Investigation of Catheter Associated Urinary Tract Infection by Enterococcus faecalis: vanA Genotype

    PubMed Central

    Padmavathy, Kesavaram; Madhavan, Radha; Krithika, Nagarajan; Kiruthiga, Alexander

    2015-01-01

    Prolonged hospitalization and exposure to third generation cephalosporins are reported to facilitate the acquisition and colonization of Vancomycin Resistant Enterococci (VRE). Though VRE is not uncommon in India, urinary tract infection with a vanA genotype is a cause of serious concern as VRE co-exhibit resistance to aminoglycosides. In India, majority of the VRE isolates recovered from hospitalized patients include Enterococcus faecium. We report a case of catheter associated urinary tract infection by an endogenous, multidrug resistant E. faecalis of vanA genotype following prolonged hospitalization, ICU stay, catheterisation and exposure to 3G cephalosporin and metronidazole. The patient responded to linezolid therapy. PMID:26435949

  14. Results from tests, with van-mounted sensor, of magnetic leader cable for aircraft guidance during roll-out and turnoff

    NASA Technical Reports Server (NTRS)

    Young, J. C.; Bundick, W. T.; Irwin, S. H.

    1983-01-01

    Tests were conducted with a van mounted experimental magnetic leader cable sensor to evaluate its potential for measuring aircraft displacement and heading with respect to the leader cable during roll out and turnoff. Test results show that the system may be usable in measuring displacement but the heading measurement contains errors introduced by distortion of the magnetic field by the metal van or aircraft.

  15. Inventory of Simulation and Modeling for the Analysis of Ground Manoeuvre Performance (inventarisatie van vragen en modellen voor de analyse van het grondgebonden optreden)

    DTIC Science & Technology

    2006-04-01

    uitvoeren, en hoe lang men deze operaties wit kunnen voortzetten. Deze vragen zijn niet binnen AGO te beantwoorden, mawr de antwoorden op deze vragen...Bovenstaande modellen zijn allen in gebruik bij DSTL. Daarnaast beschikt de DGD&D over een eigen wargame (MINERVA) waarmee men seminars ten beboeve van...gemnodelleerd. Zo zijn er voor de afzonderlijke tanks geen vuursectoren gemodelleerd waarbinnen men terugvuurt. Dit kan in de toekomnst wel verder

  16. Solving Geometric Problems by Using Algebraic Representation for Junior High School Level 3 in Van Hiele at Geometric Thinking Level

    ERIC Educational Resources Information Center

    Suwito, Abi; Yuwono, Ipung; Parta, I. Nengah; Irawati, Santi; Oktavianingtyas, Ervin

    2016-01-01

    This study aims to determine the ability of algebra students who have 3 levels van Hiele levels. Follow its framework Dindyal framework (2007). Students are required to do 10 algebra shaped multiple choice, then students work 15 about the geometry of the van Hiele level in the form of multiple choice questions. The question has been tested levels…

  17. Tri-wheeled scooters transported on buses and vans : assessment of securement restraint issues

    DOT National Transportation Integrated Search

    2005-10-01

    Under the Americans with Disabilities Act (ADA) of 1990, all "common wheelchairs and mobility aids", including tri-wheeled scooters, must be accommodated on buses and vans used in public transit service. Several transit systems have recently expresse...

  18. Beam-dynamic effects at the CMS BRIL van der Meer scans

    NASA Astrophysics Data System (ADS)

    Babaev, A.

    2018-03-01

    The CMS Beam Radiation Instrumentation and Luminosity Project (BRIL) is responsible for the simulation and measurement of luminosity, beam conditions and radiation fields in the CMS experiment. The project is engaged in operating and developing new detectors (luminometers), adequate for the experimental conditions associated with high values of instantaneous luminosity delivered by the CERN LHC . BRIL operates several detectors based on different physical principles and technologies. Precise and accurate measurements of the delivered luminosity is of paramount importance for the CMS physics program. The absolute calibration of luminosity is achieved by the van der Meer method, which is carried out under specially tailored conditions. This paper presents models used to simulate of beam-dynamic effects arising due to the electromagnetic interaction of colliding bunches. These effects include beam-beam deflection and dynamic-β effect. Both effects are important to luminosity measurements and influence calibration constants at the level of 1-2%. The simulations are carried out based on 2016 CMS van der Meer scan data for proton-proton collisions at a center-of-mass energy of 13 TeV.

  19. Spontaneous doping on high quality talc-graphene-hBN van der Waals heterostructures

    NASA Astrophysics Data System (ADS)

    Mania, E.; Alencar, A. B.; Cadore, A. R.; Carvalho, B. R.; Watanabe, K.; Taniguchi, T.; Neves, B. R. A.; Chacham, H.; Campos, L. C.

    2017-09-01

    Steady doping, added to its remarkable electronic properties, would make graphene a valuable commodity in the solar cell market, as energy power conversion could be substantially increased. Here we report a graphene van der Waals heterostructure which is able to spontaneously dope graphene (p-type) up to n ~ 2.2  ×  1013 cm-2 while providing excellent charge mobility (μ ~ 25 000 cm2 V-1 s-1). Such properties are achieved via deposition of graphene on atomically flat layered talc, a natural and abundant dielectric crystal. Raman investigation shows a preferential charge accumulation on graphene-talc van der Waals heterostructures, which are investigated through the electronic properties of talc/graphene/hBN heterostructure devices. These heterostructures preserve graphene’s good electronic quality, verified by the observation of quantum Hall effect at low magnetic fields (B  =  0.4 T) at T  =  4.2 K. In order to investigate the physical mechanisms behind graphene-on-talc p-type doping, we performed first-principles calculations of their interface structural and electronic properties. In addition to potentially improving solar cell efficiency, graphene doping via van der Waals stacking is also a promising route towards controlling the band gap opening in bilayer graphene, promoting a steady n or p type doping in graphene and, eventually, providing a new path to access superconducting states in graphene, predicted to exist only at very high doping.

  20. Selectively enhanced photocurrent generation in twisted bilayer graphene with van Hove singularity

    PubMed Central

    Yin, Jianbo; Wang, Huan; Peng, Han; Tan, Zhenjun; Liao, Lei; Lin, Li; Sun, Xiao; Koh, Ai Leen; Chen, Yulin; Peng, Hailin; Liu, Zhongfan

    2016-01-01

    Graphene with ultra-high carrier mobility and ultra-short photoresponse time has shown remarkable potential in ultrafast photodetection. However, the broad and weak optical absorption (∼2.3%) of monolayer graphene hinders its practical application in photodetectors with high responsivity and selectivity. Here we demonstrate that twisted bilayer graphene, a stack of two graphene monolayers with an interlayer twist angle, exhibits a strong light–matter interaction and selectively enhanced photocurrent generation. Such enhancement is attributed to the emergence of unique twist-angle-dependent van Hove singularities, which are directly revealed by spatially resolved angle-resolved photoemission spectroscopy. When the energy interval between the van Hove singularities of the conduction and valance bands matches the energy of incident photons, the photocurrent generated can be significantly enhanced (up to ∼80 times with the integration of plasmonic structures in our devices). These results provide valuable insight for designing graphene photodetectors with enhanced sensitivity for variable wavelength. PMID:26948537

  1. Transitional behavior of different energy protons based on Van Allen Probes observations

    SciTech Connect

    Yue, Chao; Bortnik, Jacob; Chen, Lunjin

    Understanding the dynamical behavior of ~1 eV to 50 keV ions and identifying the energies at which the morphologies transit are important in that they involve the relative intensities and distributions of the large-scale electric and magnetic fields, the outflow, and recombination rates. However, there have been only few direct observational investigations of the transition in drift behaviors of different energy ions before the Van Allen Probes era. In this paper, we statistically analyze ~1 eV to 50 keV hydrogen (H +) differential flux distributions near geomagnetic equator by using Van Allen Probes observations to investigate the H + dynamicsmore » under the regulation of large-scale electric and magnetic fields. Our survey clearly indicates three types of H + behaviors within different energy ranges, which is consistent with previous theory predictions. Finally, using simple electric and magnetic field models in UBK coordinates, we have further constrained the source regions of different energy ions and their drift directions.« less

  2. Transitional behavior of different energy protons based on Van Allen Probes observations

    DOE PAGES

    Yue, Chao; Bortnik, Jacob; Chen, Lunjin; ...

    2016-12-09

    Understanding the dynamical behavior of ~1 eV to 50 keV ions and identifying the energies at which the morphologies transit are important in that they involve the relative intensities and distributions of the large-scale electric and magnetic fields, the outflow, and recombination rates. However, there have been only few direct observational investigations of the transition in drift behaviors of different energy ions before the Van Allen Probes era. In this paper, we statistically analyze ~1 eV to 50 keV hydrogen (H +) differential flux distributions near geomagnetic equator by using Van Allen Probes observations to investigate the H + dynamicsmore » under the regulation of large-scale electric and magnetic fields. Our survey clearly indicates three types of H + behaviors within different energy ranges, which is consistent with previous theory predictions. Finally, using simple electric and magnetic field models in UBK coordinates, we have further constrained the source regions of different energy ions and their drift directions.« less

  3. Pattern-free thermal modulator via thermal radiation between Van der Waals materials

    NASA Astrophysics Data System (ADS)

    Liu, Xianglei; Shen, Jiadong; Xuan, Yimin

    2017-10-01

    Modulating heat flux provides a platform for a plethora of emerging devices such as thermal diodes, thermal transistors, and thermal memories. Here, a pattern-free noncontact thermal modulator is proposed based on the mechanical rotation between two Van der Waals films with optical axes parallel to the surfaces. A modulation contrast can reach a value higher than 5 for hexagonal Boron Nitride (hBN) films separated by a nanoscale gap distance. The dominant radiative heat exchange comes from the excitation of both Type I and Type II hyperbolic surface phonon polaritons (HSPhPs) at the vacuum-hBN interface for different orientations, while the large modulation contrast is mainly attributed to the mismatching Type I HSPhPs induced by rotation. This work opens the possibility to design cheap thermal modulators without relying on nanofabrication techniques, and paves the way to apply natural Van der Waals materials in manipulating heat currents in an active way.

  4. Impact of a Major National Evaluation Study: Israel's Van Leer Report.

    ERIC Educational Resources Information Center

    Alkin, Marvin C.; Lewy, Arieh

    This investigation documents the impact of the Van Leer Study, a large-scale evaluation study of achievement in the primary schools of Israel. It is intended to increase understanding of the process of evaluation utilization, showing how evaluation findings and other kinds of information can work together, over time and in a variety of ways, to…

  5. Improving Students' Van Hiele Level of Geometric Thinking Using Geometer's Sketchpad

    ERIC Educational Resources Information Center

    Tieng, Poh Geik; Eu, Leong Kwan

    2014-01-01

    The objective of this study was to examine the use of the Geometer's Sketchpad on students' van Hiele level of geometric thinking. A total of 31 Year Three students from a primary school in Pahang, Malaysia, participated in this study which was carried out over two weeks. The experimental group (N=16) was given the intervention using Geometer's…

  6. vanA-positive multi-drug-resistant Enterococcus spp. isolated from surfaces of a US hospital laundry facility.

    PubMed

    Michael, K E; No, D; Roberts, M C

    2017-02-01

    Enterococcus spp. are a normal part of the gastrointestinal tract of humans and animals. They are also important pathogens, being responsible for 14% of US nosocomial infections from 2007 to 2010. To examine a laundry facility that processes clinical linens for the presence and seasonality of vancomycin-resistant Enterococcus spp. Surface samples were collected four times in 2015 from the dirty and clean areas of the laundry facility. Isolates were confirmed using biochemical assays, and antibiotic susceptibility testing was performed. Further investigations included molecular characterization by multi-locus sequence typing (MLST), detection of acquired vanA and vanB and/or intrinsic vanC1 genes by polymerase chain reaction, and eBURST analysis. Seventy-four vanA-positive multi-drug-resistant Enterococcus spp. were identified: 64/120 (53%) in the dirty area and 10/120 (8%) in the clean area. There were 14 ST types among the E. faecium isolates identified (ST16, 17, 18, 117, 186, 280, 324, 412, 584, 664, 665, 736, 750 and 1038). Both E. faecalis isolates were ST109. Isolation of vancomycin-resistant enterococci (VRE) isolates was significantly higher (53% vs 8%) in the dirty area of the facility compared with the clean area. This is the first study to examine an industrial laundry facility for the presence of VRE, and may be an unrecognized reservoir. Copyright © 2016 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

  7. Earthquake prediction evaluation standards applied to the VAN Method

    NASA Astrophysics Data System (ADS)

    Jackson, David D.

    Earthquake prediction research must meet certain standards before it can be suitably evaluated for potential application in decision making. For methods that result in a binary (on or off) alarm condition, requirements include (1) a quantitative description of observables that trigger an alarm, (2) a quantitative description, including ranges of time, location, and magnitude, of the predicted earthquakes, (3) documented evidence of all previous alarms, (4) a complete list of predicted earthquakes, (5) a complete list of unpredicted earthquakes. The VAN technique [Varotsos and Lazaridou, 1991; Varotsos et al., 1996] has not yet been stated as a testable hypothesis. It fails criteria (1) and (2) so it is not ready to be evaluated properly. Although telegrams were transmitted in advance of claimed successes, these telegrams did not fully specify the predicted events, and all of the published statistical evaluations involve many subjective ex post facto decisions. Lacking a statistically demonstrated relationship to earthquakes, a candidate prediction technique should satisfy several plausibility criteria, including: (1) a reasonable relationship between the location of the candidate precursor and that of the predicted earthquake, (2) some demonstration that the candidate precursory observations are related to stress, strain, or other quantities related to earthquakes, and (3) the existence of co-seismic as well as pre-seismic variations of the candidate precursor. The VAN technique meets none of these criteria.

  8. Hermite Functional Link Neural Network for Solving the Van der Pol-Duffing Oscillator Equation.

    PubMed

    Mall, Susmita; Chakraverty, S

    2016-08-01

    Hermite polynomial-based functional link artificial neural network (FLANN) is proposed here to solve the Van der Pol-Duffing oscillator equation. A single-layer hermite neural network (HeNN) model is used, where a hidden layer is replaced by expansion block of input pattern using Hermite orthogonal polynomials. A feedforward neural network model with the unsupervised error backpropagation principle is used for modifying the network parameters and minimizing the computed error function. The Van der Pol-Duffing and Duffing oscillator equations may not be solved exactly. Here, approximate solutions of these types of equations have been obtained by applying the HeNN model for the first time. Three mathematical example problems and two real-life application problems of Van der Pol-Duffing oscillator equation, extracting the features of early mechanical failure signal and weak signal detection problems, are solved using the proposed HeNN method. HeNN approximate solutions have been compared with results obtained by the well known Runge-Kutta method. Computed results are depicted in term of graphs. After training the HeNN model, we may use it as a black box to get numerical results at any arbitrary point in the domain. Thus, the proposed HeNN method is efficient. The results reveal that this method is reliable and can be applied to other nonlinear problems too.

  9. Verification Test of Jet Industries Electra-Van 1000P,

    DTIC Science & Technology

    1980-10-01

    Assistant Secretary for Conservation and Solar Ene ion of Electric Unclassified and Hybrid Vehicles 15 I Ia. DEL S FCATIOt OWNGRADING 16. DISTRIBUTION...Propulsion Batteries Charger 24. AUSTRACT (C m ern.. Fev neeey aid Idenify by block nmtbe) - The Je 4nfduis&ieElectra-Van IOOOP is a Chrysler Corp. pickup...Electric EV -1 SCR Controller (Figure 5). The propulsion motor is a General Electric d.c. motor, 37-hp, series-wound, rated at 2039 r/min. The 1000P has a

  10. Grippers Based on Opposing Van Der Waals Adhesive Pads

    NASA Technical Reports Server (NTRS)

    Parness, Aaron (Inventor); Kennedy, Brett A. (Inventor); Heverly, Matthew C (Inventor); Cutkosky, Mark R. (Inventor); Hawkes, Elliot Wright (Inventor)

    2016-01-01

    Novel gripping structures based on van der Waals adhesive forces are disclosed. Pads covered with fibers can be activated in pairs by opposite forces, thereby enabling control of the adhesive force in an ON or OFF state. Pads can be used in groups, each comprising a group of opposite pads. The adhesive structures enable anchoring forces that can resist adverse forces from different directions. The adhesive structures can be used to enable the operation of robots on surfaces of space vehicles.

  11. Bacterial resistance to vancomycin: overproduction, purification, and characterization of VanC2 from Enterococcus casseliflavus as a D-Ala-D-Ser ligase.

    PubMed

    Park, I S; Lin, C H; Walsh, C T

    1997-09-16

    The VanC phenotype for clinical resistance of enterococci to vancomycin is exhibited by Enterococcus gallinarum and Enterococcus casseliflavus. Based on the detection of the cell precursor UDP-N-acetylmuramic acid pentapeptide intermediate terminating in D-Ala-D-Ser instead of D-Ala-D-Ala, it has been predicted that the VanC ligase would be a D-Ala-D-Ser rather than a D-Ala-D-Ala ligase. Overproduction of the E. casseliflavus ATCC 25788 vanC2 gene in Escherichia coli and its purification to homogeneity allowed demonstration of ATP-dependent D-Ala-D-Ser ligase activity. The kcat/Km2 (Km2 = Km for D-Ser or C-terminal D-Ala) ratio for D-Ala-D-Ser/D-Ala-D-Ala dipeptide formation is 270/0.69 for a 400-fold selection against D-Ala in the C-terminal position. VanC2 also has substantial D-Ala-D-Asn ligase activity (kcat/Km2 = 74 mM-1min-1).

  12. Efimov states near a Feshbach resonance and the limits of van der Waals universality at finite background scattering length

    NASA Astrophysics Data System (ADS)

    Langmack, Christian; Schmidt, Richard; Zwerger, Wilhelm

    2018-03-01

    We calculate the spectrum of three-body Efimov bound states near a Feshbach resonance within a model which accounts both for the finite range of interactions and the presence of background scattering. The latter may be due to direct interactions in an open channel or a second overlapping Feshbach resonance. It is found that background scattering gives rise to substantial changes in the trimer spectrum as a function of the detuning away from a Feshbach resonance, in particular in the regime where the background channel supports Efimov states on its own. Compared to the situation with negligible background scattering, the regime where van der Waals universality applies is shifted to larger values of the resonance strength if the background scattering length is positive. For negative background scattering lengths, in turn, van der Waals universality extends to even small values of the resonance strength parameter, consistent with experimental results on Efimov states in 39K. Within a simple model, we show that short-range three-body forces do not affect van der Waals universality significantly. Repulsive three-body forces may, however, explain the observed variation between around -8 and -10 of the ratio between the scattering length where the first Efimov trimer appears and the van der Waals length.

  13. Responsie van Verschillende Munitieartikelen bij Opwarming en Brand (Response of Munitions Items Due to Heating or a Fire)

    DTIC Science & Technology

    2007-09-01

    Verboom Auteur TNO-rapport I TNO-DV 2007 A315 BijIage A I 1I7 A Berekening thermische explosiekubus A.1 Inleiding De theorie van een thermische...Responsie van verschillende munitieartikelen bij opwarming en brand Datum scptember 2007 Auteur (s) ir.J.H.G. Scholtes ir. V. Verboorn R Ubricering rapport O...mabegeleider Projectbegeleider Setembr20 Ltkol I Paap, G.B. Cornelisse, spebr20 DMO/DWS&B/Ressort Lucht- DS/CLAS/St-CLAS/Dir OPOST Auteur (s) systeen

  14. 75 FR 63216 - Van Eck Associates Corporation, et al.; Notice of Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-14

    ... SECURITIES AND EXCHANGE COMMISSION [Investment Company Act Release No. 29459; 812-13605] Van Eck... Investment Company Act of 1940 (``Act'') for an exemption from sections 2(a)(32), 5(a)(1), 22(d) and 22(e) of... investment companies to issue shares (``Shares'') redeemable in large aggregations only (``Creation Units...

  15. Early Childhood Matters: The Bulletin of the Bernard van Leer Foundation, 2001.

    ERIC Educational Resources Information Center

    Smale, Jim, Ed.

    2001-01-01

    This document consists of the three 2001 issues of The Bernard van Leer Foundation's "Early Childhood Matters," a periodical addressed to practitioners in the field of early childhood education and including information on projects funded by the foundation. Articles in the February 2001 edition focus on fathers and include: (1)…

  16. Layer-dependent band alignment of few layers of blue phosphorus and their van der Waals heterostructures with graphene

    NASA Astrophysics Data System (ADS)

    Pontes, Renato B.; Miwa, Roberto H.; da Silva, Antônio J. R.; Fazzio, Adalberto; Padilha, José E.

    2018-06-01

    The structural and electronic properties of few layers of blue phosphorus and their van der Waals heterostructures with graphene were investigated by means of first-principles electronic structure calculations. We study the four energetically most stable stacking configurations for multilayers of blue phosphorus. For all of them, the indirect band-gap semiconductor character, are preserved. We show that the properties of monolayer graphene and single-layer (bilayer) blue phosphorus are preserved in the van der Waals heterostructures. Further, our results reveal that under a perpendicular applied electric field, the position of the band structure of blue phosphorus with respect to that of graphene is tunable, enabling the effective control of the Schottky barrier height. Indeed, for the bilayer blue phosphorene on top of graphene, it is possible to even move the system into an Ohmic contact and induce a doping level of the blue phosphorene. All of these features are fundamental for the design of new nanodevices based on van der Waals heterostructures.

  17. Ex ante Implementatietoetsing van Beleid, Een Methodiek Gebaseerd op Synergie Tussen Risicomanagement en Verandermanagement (Ex Ante Test for Policy Implementation - A Method Based Upon Synergy Between Risk Management an Change Management)

    DTIC Science & Technology

    2006-12-01

    ante implementatietoetsing van beleid Een methodiek gebaseerd op synergie tussen risicomnanagemnent en verandermanagemnent Datuni december 2006 Auteur (s...te analyseren. Het de resultaten van de interviews gebruikct bij de theorie van risicomanagement en project Verandermanagernent bij de de ontwikkehing...Opdrachtnummer Hoewel expliciet is gekeken naar voorbeelden van risico’s bij Datum december 2006 Auteur (s) PROGRAMMA PR03ECT drs. R.C.T. de Haas drs

  18. Effectiveness of autism training programme: An example from Van, Turkey.

    PubMed

    Eray, Safak; Murat, Duygu

    2017-11-01

    To determine the knowledge and attitudes of family practitioners before and after their participation in a training programme. The study was conducted at Van Training and Research Hospital, Van, Turkey, from December 1to 15, 2016, and comprised family practitioners. Before the training, the practitioners were asked to fill out a questionnaire that was prepared by the researchers. Subsequently, the training course was presented by the child and adolescent psychiatrists. After the training, participants were asked to fill out the same questionnaire again. The results of survey were compared before and after training. Data was evaluated using SPSS 22.Descriptive analyses were used and baseline characteristics were compared between groups using McNemar's test and paired t-test. Of the 79 family practitioners who filled out the questionnaire,75(94.9%) were included. The mean age of the practitioners was 28.2±11.63, with 40(53%) being females. Moreover,26(34.7%) participants thought that they had sufficient information regarding autism spectrum disorder before training, and this number increased to 66(88%) after training. There was a significant difference between pre-training and post-training scores of the questionnaire (p<0.001). There was a deficiency in knowledge about autism symptoms, aetiology, prevalence and treatment among family practitioners. .

  19. Generalization of the van der Pauw relationship derived from electrostatics

    NASA Astrophysics Data System (ADS)

    Weiss, Jonathan D.

    2011-08-01

    In an earlier paper, this author, along with two others Weiss et al. (2008) [1], demonstrated that the original van der Pauw relationship could be derived from three-dimensional electrostatics, as opposed to van der Pauw's use of conformal mapping. The earlier derivation was done for a conducting material of rectangular cross section with contacts placed at the corners. Presented here is a generalization of the previous work involving a square sample and a square array of electrodes that are not confined to the corners, since this measurement configuration could be a more convenient one. As in the previous work, the effects of non-zero sample thickness and contact size have been investigated. Buehler and Thurber derived a similar relationship using an infinite series of current images on a large and thin conducting sheet to satisfy the conditions at the boundary of the sample. The results presented here agree with theirs numerically, but analytic agreement could not be shown using any of the perused mathematical literature. By simply equating the two solutions, it appears that, as a byproduct of this work, a new mathematical relationship has been uncovered. Finally, the application of this methodology to the Hall Effect is discussed.

  20. Encounters with Insignificance in Teaching and Learning: Gus Van Sant's "Elephant"

    ERIC Educational Resources Information Center

    Sandlos, Karyn

    2009-01-01

    This article explores how a curriculum of film becomes organized by the teacher's worries about what film may open up in class. The author focuses on her own worries about showing Gus Van Sant's (2003) film, "Elephant," an elliptical and dreamlike study of the murders in 1999 of twelve students and a teacher at Columbine High School, to a class of…

  1. van der Waals-type forces in spontaneously broken supersymmetries

    NASA Astrophysics Data System (ADS)

    Radescu, E. E.

    1983-03-01

    In spontaneously broken rigid supersymmetry, Goldstone-fermion pair exchange should lead to a universal interaction between massive bodies uniquely fixed by the existing low-energy theorem. The resulting van der Waals-type potential is shown to be V(r)=-Mmπ-3F-4r-7+O(r-8), where M and m are the masses of the interacting bodies while F is the scale of the breaking. The change in the situation when the supersymmetry is promoted to a local symmetry is briefly discussed.

  2. A Van der Waals-like theory of plasma double layers

    NASA Technical Reports Server (NTRS)

    Katz, Ira; Davis, V. A.

    1989-01-01

    A theory describing plasma double layers in terms of multiple roots of the charge density expression is presented. The theory presented uses the fact that equilibrium plasmas shield small potential perturbations linearly; for high potentials, the shielding decreases. The approach is analogous to Van der Waals' theory of simple fluids in which inclusion of approximate expressions for both excluded volume and long range attractive forces sufficiently describes the first-order liquid-gas phase transition.

  3. Relentless spread and adaptation of non-typeable vanA vancomycin-resistant Enterococcus faecium: a genome-wide investigation.

    PubMed

    van Hal, Sebastiaan J; Beukers, Alicia G; Timms, Verlaine J; Ellem, Justin A; Taylor, Peter; Maley, Michael W; Newton, Peter J; Ferguson, John K; Lee, Andie; Chen, Sharon C-A; Sintchenko, Vitali

    2018-03-16

    VRE are prevalent among patients in ICUs. Non-typeable vanA VRE, due to loss of one of the genes used for MLST (pstS), have increased in Australia, suggestive of a new, hospital-acquired lineage. To understand the significance of this lineage and its transmission using WGS of strains isolated from patients in ICUs across New South Wales, Australia. A total of 240 Enterococcus faecium isolates collected between February and May 2016, and identified by conventional PCR as vanA positive, were sequenced. Isolates originated from 12 ICUs in New South Wales, grouped according to six local health districts, and represented both rectal screening swab (n = 229) and clinical (n = 11) isolates. ST analysis revealed the absence of the pstS gene in 84.2% (202 of 240) of vanA isolates. Two different non-typeable STs were present based on different allelic backbone patterns. Loss of the pstS gene appeared to be the result of multiple recombination events across this region. Evidence for pstS-negative lineage spread across all six local health districts was observed suggestive of inter-hospital transmission. In addition, multiple outbreaks were detected, some of which were protracted and lasted for the duration of the study. These findings confirmed the evolution, emergence and dissemination of non-typeable vanA E. faecium. This study has highlighted the utility of WGS when attempting to describe accurately the hospital-based pathogen epidemiology, which in turn will continue to inform optimal infection control measures necessary to halt the spread of this important nosocomial organism.

  4. 77 FR 29394 - Van Eck VIP Trust, et al.; Notice of Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-17

    ... outstanding voting stock of the registered closed-end investment company. 2. Section 12(d)(1)(J) of the Act... SECURITIES AND EXCHANGE COMMISSION [Investment Company Act Release No. 30063; 812-13846] Van Eck... Investment Company Act of 1940 (``Act'') for an exemption from sections 12(d)(1)(A) and (C) of the Act...

  5. The role of van der Waals interaction in the tilted binding of amine molecules to the Au(111) surface

    NASA Astrophysics Data System (ADS)

    Le, Duy; Aminpour, Maral; Kiejna, Adam; Rahman, Talat S.

    2012-06-01

    We present the results of ab initio electronic structure calculations for the adsorption characteristics of three amine molecules on Au(111), which show that the inclusion of van der Waals interactions between the isolated molecule and the surface leads in general to good agreement with experimental data on the binding energies. Each molecule, however, adsorbs with a small tilt angle (between -5 and 9°). For the specific case of 1,4-diaminobenzene (BDA) our calculations reproduce the larger tilt angle (close to 24°) measured by photoemission experiments, when intermolecular (van der Waals) interactions (for about 8% coverage) are included. These results point not only to the important contribution of van der Waals interactions to molecule-surface binding energy, but also that of intermolecular interactions, often considered secondary to that between the molecule and the surface, in determining the adsorption geometry and pattern formation.

  6. Two-dimensional antimonene single crystals grown by van der Waals epitaxy.

    PubMed

    Ji, Jianping; Song, Xiufeng; Liu, Jizi; Yan, Zhong; Huo, Chengxue; Zhang, Shengli; Su, Meng; Liao, Lei; Wang, Wenhui; Ni, Zhenhua; Hao, Yufeng; Zeng, Haibo

    2016-11-15

    Unlike the unstable black phosphorous, another two-dimensional group-VA material, antimonene, was recently predicted to exhibit good stability and remarkable physical properties. However, the synthesis of high-quality monolayer or few-layer antimonenes, sparsely reported, has greatly hindered the development of this new field. Here, we report the van der Waals epitaxy growth of few-layer antimonene monocrystalline polygons, their atomical microstructure and stability in ambient condition. The high-quality, few-layer antimonene monocrystalline polygons can be synthesized on various substrates, including flexible ones, via van der Waals epitaxy growth. Raman spectroscopy and transmission electron microscopy reveal that the obtained antimonene polygons have buckled rhombohedral atomic structure, consistent with the theoretically predicted most stable β-phase allotrope. The very high stability of antimonenes was observed after aging in air for 30 days. First-principle and molecular dynamics simulation results confirmed that compared with phosphorene, antimonene is less likely to be oxidized and possesses higher thermodynamic stability in oxygen atmosphere at room temperature. Moreover, antimonene polygons show high electrical conductivity up to 10 4  S m -1 and good optical transparency in the visible light range, promising in transparent conductive electrode applications.

  7. Two-dimensional antimonene single crystals grown by van der Waals epitaxy

    PubMed Central

    Ji, Jianping; Song, Xiufeng; Liu, Jizi; Yan, Zhong; Huo, Chengxue; Zhang, Shengli; Su, Meng; Liao, Lei; Wang, Wenhui; Ni, Zhenhua; Hao, Yufeng; Zeng, Haibo

    2016-01-01

    Unlike the unstable black phosphorous, another two-dimensional group-VA material, antimonene, was recently predicted to exhibit good stability and remarkable physical properties. However, the synthesis of high-quality monolayer or few-layer antimonenes, sparsely reported, has greatly hindered the development of this new field. Here, we report the van der Waals epitaxy growth of few-layer antimonene monocrystalline polygons, their atomical microstructure and stability in ambient condition. The high-quality, few-layer antimonene monocrystalline polygons can be synthesized on various substrates, including flexible ones, via van der Waals epitaxy growth. Raman spectroscopy and transmission electron microscopy reveal that the obtained antimonene polygons have buckled rhombohedral atomic structure, consistent with the theoretically predicted most stable β-phase allotrope. The very high stability of antimonenes was observed after aging in air for 30 days. First-principle and molecular dynamics simulation results confirmed that compared with phosphorene, antimonene is less likely to be oxidized and possesses higher thermodynamic stability in oxygen atmosphere at room temperature. Moreover, antimonene polygons show high electrical conductivity up to 104 S m−1 and good optical transparency in the visible light range, promising in transparent conductive electrode applications. PMID:27845327

  8. Exciton–polaritons in van der Waals heterostructures embedded in tunable microcavities

    PubMed Central

    Dufferwiel, S.; Schwarz, S.; Withers, F.; Trichet, A. A. P.; Li, F.; Sich, M.; Del Pozo-Zamudio, O.; Clark, C.; Nalitov, A.; Solnyshkov, D. D.; Malpuech, G.; Novoselov, K. S.; Smith, J. M.; Skolnick, M. S.; Krizhanovskii, D. N.; Tartakovskii, A. I.

    2015-01-01

    Layered materials can be assembled vertically to fabricate a new class of van der Waals heterostructures a few atomic layers thick, compatible with a wide range of substrates and optoelectronic device geometries, enabling new strategies for control of light–matter coupling. Here, we incorporate molybdenum diselenide/hexagonal boron nitride (MoSe2/hBN) quantum wells in a tunable optical microcavity. Part-light–part-matter polariton eigenstates are observed as a result of the strong coupling between MoSe2 excitons and cavity photons, evidenced from a clear anticrossing between the neutral exciton and the cavity modes with a splitting of 20 meV for a single MoSe2 monolayer, enhanced to 29 meV in MoSe2/hBN/MoSe2 double-quantum wells. The splitting at resonance provides an estimate of the exciton radiative lifetime of 0.4 ps. Our results pave the way for room-temperature polaritonic devices based on multiple-quantum-well van der Waals heterostructures, where polariton condensation and electrical polariton injection through the incorporation of graphene contacts may be realized. PMID:26446783

  9. Observation of novel photochemistry in the multiphoton ionization of Mo(CO) sub 6 van der Waals clusters

    SciTech Connect

    Peifer, W.R.; Garvey, J.F.

    1989-07-27

    van der Waals clusters of Mo(CO){sub 6} generated in the free-jet expansion of a pulsed beam of seeded helium are subjected to multiphoton ionization and the product ions analyzed by quadrupole mass spectrometry. Oxomolybdenum and dioxomolybdenum ions are observed to be produced with high efficiency. This behavior is in striking contrast to that of metal carbonyl monomers and covalently bound cluster carbonyls, which under complete ligand loss prior to ionization. The observed photochemistry is ascribed to reactions between a photoproduced molybdenum atom and the ligands of neighboring Mo(CO){sub 6} solvent molecules within the van der Waals cluster.

  10. Ductal carcinoma in situ: USC/Van Nuys Prognostic Index and the impact of margin status.

    PubMed

    Silverstein, Melvin J; Buchanan, Claire

    2003-12-01

    As our knowledge of ductal carcinoma in situ (DCIS) continues to evolve, treatment decision-making has become increasingly complex and controversial for both patients and physicians. Treatment options include mastectomy, and breast conservation with or without radiation therapy. Data produced from the randomized clinical trials for DCIS has provided the basis for important treatment recommendations, but are not without limitations. In this article, we review our prospectively collected database consisting of 1036 patients with DCIS treated at the Van Nuys Breast Center and the USC/Norris Comprehensive Cancer Center. We review the use of the USC/Van Nuys Prognostic Index, a clinical algorithm designed to assist physicians in selection of appropriate treatments, and examine the impact of margin status as a sole predictor of local recurrence.

  11. van der Waals epitaxy of Ge films on mica

    NASA Astrophysics Data System (ADS)

    Littlejohn, A. J.; Xiang, Y.; Rauch, E.; Lu, T.-M.; Wang, G.-C.

    2017-11-01

    To date, many materials have been successfully grown on substrates through van der Waals epitaxy without adhering to the constraint of lattice matching as is required for traditional chemical epitaxy. However, for elemental semiconductors such as Ge, this has been challenging and therefore it has not been achieved thus far. In this paper, we report the observation of Ge epitaxially grown on mica at a narrow substrate temperature range around 425 °C. Despite the large lattice mismatch (23%) and the lack of high in-plane symmetry in the mica surface, an epitaxial Ge film with [111] out-of-plane orientation is observed. Crystallinity and electrical properties degrade upon deviation from the ideal growth temperature, as shown by Raman spectroscopy, X-ray diffraction, and Hall effect measurements. X-ray pole figure analysis reveals that there exist multiple rotational domains in the epitaxial Ge film with dominant in-plane orientations between Ge [" separators="|1 ¯10 ] and mica[100] of (20 n )°, where n = 0, 1, 2, 3, 4, 5. A superlattice area mismatch model was used to account for the likelihood of the in-plane orientation formation and was found to be qualitatively consistent with the observed dominant orientations. Our observation of Ge epitaxy with one out-of-plane growth direction through van der Waals forces is a step toward the growth of single crystal Ge films without the constraint in the lattice and symmetry matches with the substrates.

  12. Magnetohydrodynamic modeling of three Van Allen Probes storms in 2012 and 2013

    NASA Astrophysics Data System (ADS)

    Paral, J.; Hudson, M. K.; Kress, B. T.; Wiltberger, M. J.; Wygant, J. R.; Singer, H. J.

    2015-08-01

    Coronal mass ejection (CME)-shock compression of the dayside magnetopause has been observed to cause both prompt enhancement of radiation belt electron flux due to inward radial transport of electrons conserving their first adiabatic invariant and prompt losses which at times entirely eliminate the outer zone. Recent numerical studies suggest that enhanced ultra-low frequency (ULF) wave activity is necessary to explain electron losses deeper inside the magnetosphere than magnetopause incursion following CME-shock arrival. A combination of radial transport and magnetopause shadowing can account for losses observed at radial distances into L = 4.5, well within the computed magnetopause location. We compare ULF wave power from the Electric Field and Waves (EFW) electric field instrument on the Van Allen Probes for the 8 October 2013 storm with ULF wave power simulated using the Lyon-Fedder-Mobarry (LFM) global magnetohydrodynamic (MHD) magnetospheric simulation code coupled to the Rice Convection Model (RCM). Two other storms with strong magnetopause compression, 8-9 October 2012 and 17-18 March 2013, are also examined. We show that the global MHD model captures the azimuthal magnetosonic impulse propagation speed and amplitude observed by the Van Allen Probes which is responsible for prompt acceleration at MeV energies reported for the 8 October 2013 storm. The simulation also captures the ULF wave power in the azimuthal component of the electric field, responsible for acceleration and radial transport of electrons, at frequencies comparable to the electron drift period. This electric field impulse has been shown to explain observations in related studies (Foster et al., 2015) of electron acceleration and drift phase bunching by the Energetic Particle, Composition, and Thermal Plasma Suite (ECT) instrument on the Van Allen Probes.

  13. Reply to “Statistical evaluation of the VAN Method using the historic earthquake catalog in Greece,” by Richard L. Aceves, Stephen K. Park and David J. Strauss

    NASA Astrophysics Data System (ADS)

    Varotsos, P.; Lazaridou, M.

    The pioneering calculation by Aceves et al. [1996] shed light on the main question of this debate, i.e., on whether “VAN predictions can be ascribed to chance.” Aceves et al. [1996] conclude that “the VAN method has resulted in a significantly higher prediction rate than randomly sampling a PDF (probability density function) map generated from a 25 year history of earthquakes.” After investigating the totality of VAN predictions issued during the period 1987-1989, Aceves et al. [1996] found: “The prediction rate for the VAN method clearly exceeds that from the random model at all time lags between 5-22 days. At a 5 day time lag, the VAN prediction rate of 35.7% has a P-value of less than 0.06%. This means that a random model does as well as does the VAN method less than 0.06% of the time. At 22 days, the prediction rate of 67.9% has a P-value of less than 0.07%.” These conclusions basically coincide with those of Hamada [1993] although Aceves et al. [1996] followed different procedures. They are also in fundamental agreement with the results of Honkura and Tanaka [1996]. Another important conclusion of Aceves et al. [1996] is that, after declustering the earthquake catalog and prediction list from aftershocks, “VAN method is still formally significant.”

  14. Biomarkers in Lake Van sediments reveal dry conditions in eastern Anatolia during 110.000-10.000 years B.P.

    NASA Astrophysics Data System (ADS)

    Randlett, Marie-Eve; Bechtel, Achim; van der Meer, Marcel T. J.; Peterse, Francien; Litt, Thomas; Pickarski, Nadine; Kwiecien, Ola; Stockhecke, Mona; Wehrli, Bernhard; Schubert, Carsten J.

    2017-02-01

    Lipid biomarkers were analyzed in Lake Van sediments covering the last 600 ka, with a focus on the period between 110 and 10 ka, when a broad maximum in pore water salinity as a relict from the past suggests dry conditions. The occurrence and distribution of biomarkers indicative for terrestrial plants (long-chain n-alkane C29), haptophyte algae (methyl alkenones C37) and halophilic archaea (archaeol) all point toward a dry climate in Lake Van region during this time interval. The hydrogen isotopic composition of C29 n-alkanes (δDC29) and C37 alkenones (δDC37) is enriched between MIS 4 and MIS 2, which is interpreted as a decrease in the regional ratio of precipitation to evaporation. Similarly, the low abundance of the acyclic glycerol dialkyl glycerol tetraether GDGT-0 relative to archaeol, quantified by the Archaeol and Caldarchaeol Ecometric (ACE) is assumed to reflect the presence of halophilic euryarchaeota adapted to high salinity water. The climate around Lake Van appears in phase with the Yammouneh basin 800 km southwest and Lake Urmia 250 km southeast of Lake Van over the last two glacial periods. The results highlight the potential of combining ACE, δDC29, and δDC37 for reconstructing salinity changes and regional precipitation to evaporation ratio from lake sediments.

  15. A false alarm based on electrical activity recorded at a VAN-Station in northern Greece in December 1990

    NASA Astrophysics Data System (ADS)

    Drakopoulos, John; Stavrakakis, George N.

    A VAN-prediction was announced on January 6, 1991, through the French newspaper “Le Monde” and on January 8-10, 1991, through Greek newspapers and TV stations. We evaluate this prediction on the basis of a letter which was sent by Prof. Varotsos (without date) to the Greek Minister of Public Works, and by considering previous VAN-publications as well as recent seismological data for the candidate regions. We conclude that what was observed at ASS station (northern Greece) on December 31, 1990, was not SES-activity but another disturbance or noise.

  16. Bewegingshinder van Impactbeschermingsmiddelen voor de ME van de KMar (Restriction of Movement of Impact Protective Clothing for the Anti-Riot Squad of the Dutch Military Police)

    DTIC Science & Technology

    2007-12-01

    kleding. omnstandigheden. zoals borst. armen en benen. Omdat er geen De nieuwe kieding met impactbLscherming bestaand testprotocol voor het testen van...verschillende onderdelen die bescherming biedt op diverse plaatsen op bet lichaam zoals borst, armen en benen. Orndat er geen bestaand testprotocol voor bet... armen en benen, Hieronder wordt kort omischreven welke ergonomische testen uitgevoerd moesten worden. 2.6.1 Sprint Bij een korte sprint (10 meter

  17. Selection of a Method for the Measurement of the Protection Factor in the Field (Selectie van een methode voor de meting van de gasmaskerprotectiefactor te velde)

    DTIC Science & Technology

    1998-06-01

    deeltjes in het masker, de luclitwegen of de detector worden protectiefactoren gevonden die in het algemneen te optimistisch zijn [11, 12]. De gevonden...zijn wel te relateren aan bepaalde activiteiten. 4.2.2 Natuurlijk atmosferisch stof Door de firma TSI is een apparaat ontwikkeld (Portacount) dat...onderdruk afnemen [5]. Door de firma Dynatech Nevada (USA) wordt een apparaat geproduceerd dat van dit principe gebruikmaakt. Het apparaat is voorzien

  18. Polyradiculopathies from schwannomatosis.

    PubMed

    Jia, Yuxia; Kraus, James A; Reddy, Hasini; Groff, Michael; Wong, Eric T

    2011-01-01

    We describe a case of schwannomatosis presenting as radicular pain and numbness in multiple radicular nerve distributions. There were multiple peripheral nerve tumors detected by magnetic resonance imaging (MRI) at the left vestibular nerve, cauda equina, right radial nerve, thoracic paraspinal nerve, and brachial plexi. Several resected tumors have features of schwannomas, including hypercellular Antoni A areas, hypocellular Antoni B areas, Verocay bodies, and hyalinized blood vessels. The specimens are also positive for immunohistochemical staining for INI1 with diffuse nuclear staining. The findings are consistent with sporadic form of schwannomatosis. This case highlights the importance of using MRI and INI1 immunohistochemistry to differentiate familial schwannomatosis, neurofibromatosis 2 (NF2)-associated schwannomatosis, and sporadic schwannomatosis.

  19. Polyradiculopathies from Schwannomatosis

    PubMed Central

    Jia, Yuxia; Kraus, James A.; Reddy, Hasini; Groff, Michael; Wong, Eric T

    2011-01-01

    We describe a case of schwannomatosis presenting as radicular pain and numbness in multiple radicular nerve distributions. There were multiple peripheral nerve tumors detected by magnetic resonance imaging (MRI) at the left vestibular nerve, cauda equina, right radial nerve, thoracic paraspinal nerve, and brachial plexi. Several resected tumors have features of schwannomas, including hypercellular Antoni A areas, hypocellular Antoni B areas, Verocay bodies, and hyalinized blood vessels. The specimens are also positive for immunohistochemical staining for INI1 with diffuse nuclear staining. The findings are consistent with sporadic form of schwannomatosis. This case highlights the importance of using MRI and INI1 immunohistochemistry to differentiate familial schwannomatosis, neurofibromatosis 2 (NF2)-associated schwannomatosis, and sporadic schwannomatosis. PMID:21643503

  20. Low-Voltage Complementary Electronics from Ion-Gel-Gated Vertical Van der Waals Heterostructures

    SciTech Connect

    Choi, Yongsuk; Kang, Junmo; Jariwala, Deep

    2016-03-22

    Low-voltage complementary circuits comprising n-type and p-type van der Waals heterojunction vertical field-effect transistors (VFETs) are demonstrated. The resulting VFETs possess high on-state current densities (>3000 A cm-2) and on/off current ratios (>104) in a narrow voltage window (<3 V).

  1. Occurrence of oil in the Austin Chalk at Van field, Van Zandt County, Texas: A unique geologic setting

    SciTech Connect

    Lowe, J.T.; Carrington, D.B.

    1990-09-01

    The Austin Chalk is buried to a depth of only 2,100-2,500 ft and has retained primary microporosity unlike the typical deep fractured chalk reservoirs. The Van structure is a complexly faulted domal anticline created by salt intrusion and is approximately 2,000 ft higher than surrounding structures in the area. A major northwest-dipping fault acts as the primary trapping mechanism. The field has produced 0.5 billion BO from thick Woodbine sands since its discovery in 1929. Occurrence of oil in the Austin Chalk has been known since the field discovery, but prior completions were low rate oil producers. Recent development ofmore » a large fracture stimulation technique has resulted in increased production rates of up to 300 BOPD. The Austin Chalk reservoir limits were determined by isopaching feet of minimum productive resistivity having porosity above a cutoff value. The resistivity/porosity isopach showed a direct correlation between Austin Chalk productivity and the Austin Chalk structure and faulting pattern. Structural evidence along with oil typing indicate that the oil in the Austin Chalk has migrated upward along fault planes and through fault juxtaposition from the Woodbine sands 200 ft below the Austin Chalk. Thin-section and scanning electron microscopy work performed on conventional cores showed that the Van Austin Chalk formation is a very fine grained limestone composed primarily of coccoliths. Various amounts of detrital illite clay are present in the coccolith matrix. All effective porosity is micro-intergranular and ranges from 15 to 35%. Based on the core analyses, the main porosity reducing agent and therefore control on reservoir quality is the amount of detrital clay present filling the micropores. Permeability is very low with values ranging from 0.01 to 1.5 md. There is no evidence of significant natural fractures in the core. Artificial fractures are therefore required to create the permeability needed to sustain commercial production rates.« less

  2. Polynomial-interpolation algorithm for van der Pauw Hall measurement in a metal hydride film

    NASA Astrophysics Data System (ADS)

    Koon, D. W.; Ares, J. R.; Leardini, F.; Fernández, J. F.; Ferrer, I. J.

    2008-10-01

    We apply a four-term polynomial-interpolation extension of the van der Pauw Hall measurement technique to a 330 nm Mg-Pd bilayer during both absorption and desorption of hydrogen at room temperature. We show that standard versions of the van der Pauw DC Hall measurement technique produce an error of over 100% due to a drifting offset signal and can lead to unphysical interpretations of the physical processes occurring in this film. The four-term technique effectively removes this source of error, even when the offset signal is drifting by an amount larger than the Hall signal in the time interval between successive measurements. This technique can be used to increase the resolution of transport studies of any material in which the resistivity is rapidly changing, particularly when the material is changing from metallic to insulating behavior.

  3. Application of DNA probes for rRNA and vanA genes to investigation of a nosocomial cluster of vancomycin-resistant enterococci.

    PubMed Central

    Woodford, N; Morrison, D; Johnson, A P; Briant, V; George, R C; Cookson, B

    1993-01-01

    DNA probes specific for genes encoding rRNA and the glycopeptide resistance gene vanA were used to investigate a cluster of vancomycin-resistant (MICs, > 512 mg/liter) Enterococcus faecalis and Enterococcus faecium isolated from separate patients in a renal unit in a London hospital. When digested with BamHI, 12 of 13 vancomycin-resistant E. faecalis isolates exhibited a common restriction fragment length polymorphism pattern of rRNA genes (ribotype). A vanA probe hybridized with chromosomal DNA in these 12 isolates. The other isolate of vancomycin-resistant E. faecalis had a different ribotype and the vanA gene was located on plasmid DNA. These data suggest that cross-infection with a single strain of vancomycin-resistant E. faecalis occurred in most instances. In contrast, 23 vancomycin-resistant E. faecium isolates showed greater heterogeneity, comprising 8 ribotypes, suggesting that multiple strains were present in the unit. Twenty-one of these 23 isolates harbored a 24-MDa plasmid which hybridized with the vanA probe, implying that interstrain dissemination of a vancomycin resistance plasmid may have occurred among E. faecium isolates in the renal unit. Images PMID:8096216

  4. Veggie Van Pilot Study: Impact of a Mobile Produce Market for Underserved Communities on Fruit and Vegetable Access and Intake

    PubMed Central

    Leone, Lucia A.; Haynes-Maslow, Lindsey; Ammerman, Alice S.

    2016-01-01

    We conducted a pilot evaluation of the Veggie Van, a mobile produce market that brings weekly boxes of reduced-cost locally grown fruits and vegetables (F&V) to lower-income communities and offers cooking and nutrition education to customers. We conducted surveys just prior to starting Veggie Van at each of 3 sites and again at 2–3 months. F&V intake was measured with a 2-question item and a 10-item food frequency questionnaire (FFQ) in a subset of participants. At baseline, average servings/day of F&V was 4.9 (SD = 2.6, n = 60). At follow-up, individuals who reported shopping at Veggie Van frequently (n = 32) increased their F&V consumption by 0.41 servings/day compared with a decrease of −1.19 for those who rarely/never used Veggie Van (n = 27), a total difference of 1.6 servings/day (P = .01). There were no statistically significant differences in F&V consumption between groups based on the FFQ measure. Frequent shoppers reported additional health improvements and increases in their ability to buy enough F&V. We conclude that offering weekly boxes of affordable F&V paired with education in underserved communities may improve F&V consumption for frequent program users. PMID:28529669

  5. Veggie Van Pilot Study: Impact of a Mobile Produce Market for Underserved Communities on Fruit and Vegetable Access and Intake.

    PubMed

    Leone, Lucia A; Haynes-Maslow, Lindsey; Ammerman, Alice S

    2017-01-01

    We conducted a pilot evaluation of the Veggie Van, a mobile produce market that brings weekly boxes of reduced-cost locally grown fruits and vegetables (F&V) to lower-income communities and offers cooking and nutrition education to customers. We conducted surveys just prior to starting Veggie Van at each of 3 sites and again at 2-3 months. F&V intake was measured with a 2-question item and a 10-item food frequency questionnaire (FFQ) in a subset of participants. At baseline, average servings/day of F&V was 4.9 (SD = 2.6, n = 60). At follow-up, individuals who reported shopping at Veggie Van frequently (n = 32) increased their F&V consumption by 0.41 servings/day compared with a decrease of -1.19 for those who rarely/never used Veggie Van (n = 27), a total difference of 1.6 servings/day (P = .01). There were no statistically significant differences in F&V consumption between groups based on the FFQ measure. Frequent shoppers reported additional health improvements and increases in their ability to buy enough F&V. We conclude that offering weekly boxes of affordable F&V paired with education in underserved communities may improve F&V consumption for frequent program users.

  6. The evaluation of damage mechanism of unreinforced masonry buildings after Van (2011) and Elazig (2010) Earthquakes

    NASA Astrophysics Data System (ADS)

    Güney, D.; Aydin, E.; Öztürk, B.

    2015-07-01

    On March 8th, 2010 Karakocan-Elazig earthquake of magnitude 6.0 occurred at a region where masonry and adobe construction is very common. Karakocan-Elazig is located in a high seismicity region on Eastern Anatolian Fault System (EAFS). Due to the earthquake, 42 people were killed and 14’113 buildings were damaged. Another city, Van located at South east of Turkey is hit by earthquakes with M = 7.2 occurred on October 23rd, 2011 at 13:41 (local time), whose epicenter was about 16 km north of Van (Tabanli village) and M = 5.6 on November 9th, 2011 with an epicenter near the town of Edremit, south of Van and caused the loss of life and heavy damages. Both earthquakes killed 644 people and 2608 people were injured. Approximately 10’000 buildings were seriously damaged. There are many traditional types of structures existing in the region hit by earthquakes (both Van and Elazig). These buildings were built as adobe, unreinforced masonry or mixed type. These types of buildings are very common in rural areas (especially south and east) of Turkey because of easy workmanship and cheap construction cost. Many of those traditional type structures experienced serious damages. The use of masonry is very common in some of the world's most hazard-prone regions, such as in Latin America, Africa, the Indian subcontinent and other parts of Asia, the Middle East, and southern Europe. Based on damage and failure mechanism of those buildings, the parameters affecting the seismic performance of those traditional buildings are analyzed in this paper. The foundation type, soil conditions, production method of the masonry blocks, construction method, the geometry of the masonry walls, workmanship quality, existence of wooden beams, type of roof, mortar between adobe blocks are studied in order to understand the reason of damage for these types of buildings.

  7. Giant magnetic splitting inducing near-unity valley polarization in van der Waals heterostructures.

    PubMed

    Nagler, Philipp; Ballottin, Mariana V; Mitioglu, Anatolie A; Mooshammer, Fabian; Paradiso, Nicola; Strunk, Christoph; Huber, Rupert; Chernikov, Alexey; Christianen, Peter C M; Schüller, Christian; Korn, Tobias

    2017-11-16

    Monolayers of semiconducting transition metal dichalcogenides exhibit intriguing fundamental physics of strongly coupled spin and valley degrees of freedom for charge carriers. While the possibility of exploiting these properties for information processing stimulated concerted research activities towards the concept of valleytronics, maintaining control over spin-valley polarization proved challenging in individual monolayers. A promising alternative route explores type II band alignment in artificial van der Waals heterostructures. The resulting formation of interlayer excitons combines the advantages of long carrier lifetimes and spin-valley locking. Here, we demonstrate artificial design of a two-dimensional heterostructure enabling intervalley transitions that are not accessible in monolayer systems. The resulting giant effective g factor of -15 for interlayer excitons induces near-unity valley polarization via valley-selective energetic splitting in high magnetic fields, even after nonselective excitation. Our results highlight the potential to deterministically engineer novel valley properties in van der Waals heterostructures using crystallographic alignment.

  8. Strong room-temperature ferromagnetism in VSe2 monolayers on van der Waals substrates

    NASA Astrophysics Data System (ADS)

    Bonilla, Manuel; Kolekar, Sadhu; Ma, Yujing; Diaz, Horacio Coy; Kalappattil, Vijaysankar; Das, Raja; Eggers, Tatiana; Gutierrez, Humberto R.; Phan, Manh-Huong; Batzill, Matthias

    2018-04-01

    Reduced dimensionality and interlayer coupling in van der Waals materials gives rise to fundamentally different electronic1, optical2 and many-body quantum3-5 properties in monolayers compared with the bulk. This layer-dependence permits the discovery of novel material properties in the monolayer regime. Ferromagnetic order in two-dimensional materials is a coveted property that would allow fundamental studies of spin behaviour in low dimensions and enable new spintronics applications6-8. Recent studies have shown that for the bulk-ferromagnetic layered materials CrI3 (ref. 9) and Cr2Ge2Te6 (ref. 10), ferromagnetic order is maintained down to the ultrathin limit at low temperatures. Contrary to these observations, we report the emergence of strong ferromagnetic ordering for monolayer VSe2, a material that is paramagnetic in the bulk11,12. Importantly, the ferromagnetic ordering with a large magnetic moment persists to above room temperature, making VSe2 an attractive material for van der Waals spintronics applications.

  9. Phase diagram for the Kuramoto model with van Hemmen interactions.

    PubMed

    Kloumann, Isabel M; Lizarraga, Ian M; Strogatz, Steven H

    2014-01-01

    We consider a Kuramoto model of coupled oscillators that includes quenched random interactions of the type used by van Hemmen in his model of spin glasses. The phase diagram is obtained analytically for the case of zero noise and a Lorentzian distribution of the oscillators' natural frequencies. Depending on the size of the attractive and random coupling terms, the system displays four states: complete incoherence, partial synchronization, partial antiphase synchronization, and a mix of antiphase and ordinary synchronization.

  10. Van der Pol and the history of relaxation oscillations: Toward the emergence of a concept

    NASA Astrophysics Data System (ADS)

    Ginoux, Jean-Marc; Letellier, Christophe

    2012-06-01

    Relaxation oscillations are commonly associated with the name of Balthazar van der Pol via his paper (Philosophical Magazine, 1926) in which he apparently introduced this terminology to describe the nonlinear oscillations produced by self-sustained oscillating systems such as a triode circuit. Our aim is to investigate how relaxation oscillations were actually discovered. Browsing the literature from the late 19th century, we identified four self-oscillating systems in which relaxation oscillations have been observed: (i) the series dynamo machine conducted by Gérard-Lescuyer (1880), (ii) the musical arc discovered by Duddell (1901) and investigated by Blondel (1905), (iii) the triode invented by de Forest (1907), and (iv) the multivibrator elaborated by Abraham and Bloch (1917). The differential equation describing such a self-oscillating system was proposed by Poincaré for the musical arc (1908), by Janet for the series dynamo machine (1919), and by Blondel for the triode (1919). Once Janet (1919) established that these three self-oscillating systems can be described by the same equation, van der Pol proposed (1926) a generic dimensionless equation which captures the relevant dynamical properties shared by these systems. Van der Pol's contributions during the period of 1926-1930 were investigated to show how, with Le Corbeiller's help, he popularized the "relaxation oscillations" using the previous experiments as examples and, turned them into a concept.

  11. Porewater salinity reveals past lake-level changes in Lake Van, the Earth's largest soda lake.

    PubMed

    Tomonaga, Yama; Brennwald, Matthias S; Livingstone, David M; Kwiecien, Olga; Randlett, Marie-Ève; Stockhecke, Mona; Unwin, Katie; Anselmetti, Flavio S; Beer, Jürg; Haug, Gerald H; Schubert, Carsten J; Sturm, Mike; Kipfer, Rolf

    2017-03-22

    In closed-basin lakes, sediment porewater salinity can potentially be used as a conservative tracer to reconstruct past fluctuations in lake level. However, until now, porewater salinity profiles did not allow quantitative estimates of past lake-level changes because, in contrast to the oceans, significant salinity changes (e.g., local concentration minima and maxima) had never been observed in lacustrine sediments. Here we show that the salinity measured in the sediment pore water of Lake Van (Turkey) allows straightforward reconstruction of two major transgressions and a major regression that occurred during the last 250 ka. We observed strong changes in the vertical salinity profiles of the pore water of the uppermost 100 m of the sediments in Lake Van. As the salinity balance of Lake Van is almost at steady-state, these salinity changes indicate major lake-level changes in the past. In line with previous studies on lake terraces and with seismic and sedimentological surveys, we identify two major transgressions of up to +105 m with respect to the current lake level at about 135 ka BP and 248 ka BP starting at the onset of the two previous interglacials (MIS5e and MIS7), and a major regression of about -200 m at about 30 ka BP during the last ice age.

  12. Development and evaluation of a Quadruplex Taq Man real-time PCR assay for simultaneous detection of clinical isolates of Enterococcus faecalis, Enterococcus faecium and their vanA and vanB genotypes.

    PubMed

    Naserpour Farivar, Taghi; Najafipour, Reza; Johari, Pouran; Aslanimehr, Masoumeh; Peymani, Amir; Jahani Hashemi, Hoasan; Mirzaui, Baman

    2014-10-01

    We developed and evaluated the utility of a quadruplex Taqman real-time PCR assay that allows simultaneous identification of vancomycin-resistant genotypes and clinically relevant enterococci. The specificity of the assay was tested using reference strains of vancomycin-resistant and susceptible enterococci. In total, 193 clinical isolates were identified and subsequently genotyped using a Quadruplex Taqman real-time PCR assay and melting curve analysis. Representative Quadruplex Taqman real-time PCR amplification curve were obtained for Enterococcus faecium, Enterococcus faecalis, vanA-containing E. faecium, vanB-containing E. faecalis. Phenotypic and genotypic analysis of the isolates gave same results for 82 enterococcal isolates, while in 5 isolates, they were inconsistent. We had three mixed strains, which were detected by the TaqMan real-time PCR assay and could not be identified correctly using phenotypic methods. Vancomycin resistant enterococci (VRE) genotyping and identification of clinically relevant enterococci were rapidly and correctly performed using TaqMan real-time multiplex real-time PCR assay.

  13. Morphological and immunohistochemical diversity of endometrial stromal sarcoma in rats.

    PubMed

    Kumabe, Shino; Sato, Junko; Tomonari, Yuki; Takahashi, Miwa; Inoue, Kaoru; Yoshida, Midori; Doi, Takuya; Wako, Yumi; Tsuchitani, Minoru

    2018-04-01

    To clarify the histopathological characteristics of rat endometrial stromal sarcoma (ESS), we morphologically reviewed 12 malignant uterine tumors protruding into the lumen in previous rat carcinogenicity studies. The 12 cases were classified into the following 6 types based on their morphological features: spindle cell and collagen rich type, pleomorphic/spindle cell and compact type, decidual alteration type, histiocytic and multinucleated giant cell mixture type, Antoni A-type schwannoma type, and Antoni B-type schwannoma type. Immunohistochemically, tumor cells in all cases exhibited focal or diffuse positive reactions for vimentin, and 11 of the 12 cases were positive for S-100. Interestingly, 9 cases were positive for desmin or αSMA, indicating tumor cells expressing smooth muscle properties. Both Antoni A- and B-type schwannoma types showed low reactions for both muscle markers. Positive results for estrogen receptor α in the 11 cases suggested that they were derived from endometrial stromal cells. On the basis of their immunohistochemical profiles, they were considered to be derived from endometrial stromal cells while they showed morphological variation. The detection of a basement membrane surrounding tumor cells might not be a definitive indicator for differential diagnosis of ESS from malignant schwannoma. In conclusion, ESS could exhibit wide morphological and immunohistochemical variation including features of schwannoma or smooth muscle tumor.

  14. Inventory of Materials to be Used in Explosive Effects Mitigating Structures (Inventarisatie van materialen te gebruiken in constructies ter afscherming van explosie-effecten)

    DTIC Science & Technology

    2008-11-01

    F +31 15 284 39 91 info-DenV@tno.nl TNO-rapportnummer TNO-DV 2008 A357 Opdrachtnummer Datum november 2008 Auteur (s) ir. O.C. van der Jagt...een keramisch materiaal (ZrSiO.*). TNO-rapport | TNO-DV 2008 A357 32/44 K, 04 035 0.3 0 25 02 0 15 01 005 0 O a 0 X A • • Theory ...47] Molinari. A., et al., Modeling plastic shocks in periodic laminates with gradient plasticity theories . Journal of the Mechanics and Physics of

  15. 77 FR 25780 - Culturally Significant Objects Imported for Exhibition Determinations: “Rembrandt, Van Dyck...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-01

    ... DEPARTMENT OF STATE [Public Notice 7863] Culturally Significant Objects Imported for Exhibition Determinations: ``Rembrandt, Van Dyck, Gainsborough: The Treasures of Kenwood House, London'' SUMMARY: Notice is... House, London,'' imported from abroad by the American Federation of Arts for temporary exhibition within...

  16. A Small Awakening. The Work of the Bernard van Leer Foundation: 1965-1986.

    ERIC Educational Resources Information Center

    Philp, Hugh; Chetley, Andrew

    The development of the Bernard van Leer Foundation is recounted. The discussion illustrates general trends by means of selective project reviews and references to theoretical discussions which were prevalent in early childhood education during the period from 1965-1986. Also considered are activities encouraged by the foundation which have…

  17. The role of collective motion in the ultrafast charge transfer in van der Waals heterostructures

    DOE PAGES

    Wang, Han; Bang, Junhyeok; Sun, Yiyang; ...

    2016-05-10

    Here, the success of van der Waals (vdW) heterostructures, made of graphene, metal dichalcogenides, and other layered materials, hinges on the understanding of charge transfer across the interface as the foundation for new device concepts and applications. In contrast to conventional heterostructures, where a strong interfacial coupling is essential to charge transfer, recent experimental findings indicate that vdW heterostructues can exhibit ultra-fast charge transfer despite the weak binding of the heterostructure. Using time-dependent density functional theory molecular dynamics, we identify a strong dynamic coupling between the vdW layers associated with charge transfer. This dynamic coupling results in rapid nonlinear coherentmore » charge oscillations which constitute a purely electronic phenomenon and are shown to be a general feature of vdW heterostructures provided they have a critical minimum dipole coupling. Application to MoS2/WS2 heterostructure yields good agreement with experiment, indicating near complete charge transfer within a timescale of 100 fs.The success of van der Waals heterostructures made of graphene, metal dichalcogenides and other layered materials, hinges on the understanding of charge transfer across the interface as the foundation for new device concepts and applications. In contrast to conventional heterostructures, where a strong interfacial coupling is essential to charge transfer, recent experimental findings indicate that van der Waals heterostructues can exhibit ultrafast charge transfer despite the weak binding of these heterostructures. Here we find, using time-dependent density functional theory molecular dynamics, that the collective motion of excitons at the interface leads to plasma oscillations associated with optical excitation. By constructing a simple model of the van der Waals heterostructure, we show that there exists an unexpected criticality of the oscillations, yielding rapid charge transfer across the

  18. The role of collective motion in the ultrafast charge transfer in van der Waals heterostructures

    SciTech Connect

    Wang, Han; Bang, Junhyeok; Sun, Yiyang

    Here, the success of van der Waals (vdW) heterostructures, made of graphene, metal dichalcogenides, and other layered materials, hinges on the understanding of charge transfer across the interface as the foundation for new device concepts and applications. In contrast to conventional heterostructures, where a strong interfacial coupling is essential to charge transfer, recent experimental findings indicate that vdW heterostructues can exhibit ultra-fast charge transfer despite the weak binding of the heterostructure. Using time-dependent density functional theory molecular dynamics, we identify a strong dynamic coupling between the vdW layers associated with charge transfer. This dynamic coupling results in rapid nonlinear coherentmore » charge oscillations which constitute a purely electronic phenomenon and are shown to be a general feature of vdW heterostructures provided they have a critical minimum dipole coupling. Application to MoS2/WS2 heterostructure yields good agreement with experiment, indicating near complete charge transfer within a timescale of 100 fs.The success of van der Waals heterostructures made of graphene, metal dichalcogenides and other layered materials, hinges on the understanding of charge transfer across the interface as the foundation for new device concepts and applications. In contrast to conventional heterostructures, where a strong interfacial coupling is essential to charge transfer, recent experimental findings indicate that van der Waals heterostructues can exhibit ultrafast charge transfer despite the weak binding of these heterostructures. Here we find, using time-dependent density functional theory molecular dynamics, that the collective motion of excitons at the interface leads to plasma oscillations associated with optical excitation. By constructing a simple model of the van der Waals heterostructure, we show that there exists an unexpected criticality of the oscillations, yielding rapid charge transfer across the

  19. Bepaling Referentiewaarden voor Ergonomie en Warmtebelasting van Lichtgewicht Bommenpakken (Determination of Ergonomic and Thermal Load Tests and Assessment of Reference Values With Light Weight Bomb Disposal Suits)

    DTIC Science & Technology

    2008-05-01

    bommenpakken kunnen geven bij bewegingen worden gemeten met de volgende bewegingbeperkingtests: sit-and-reach, stand-and-reach, abductie van de armen ...anteflexie van de armen en beperking van zicht. Bij de sit-and-reach test komt een eventuele belernmering bij het voorover buigen naar voren. De...proefpersoon zit op de grond met de benen en armen gestrekt naar voren. Daarbij wordt de afstand tussen de tenen en de vingers gemeten (figuur 4). Als het pak

  20. Generalization of the van der Pauw Method: Analyzing Longitudinal Magnetoresistance Asymmetry to Quantify Doping Gradients

    NASA Astrophysics Data System (ADS)

    Grayson, M.; Zhou, Wang; Yoo, Heun-Mo; Prabhu-Gaunkar, S.; Tiemann, L.; Reichl, C.; Wegscheider, W.

    A longitudinal magnetoresistance asymmetry (LMA) between a positive and negative magnetic field is known to occur in both the extreme quantum limit and the classical Drude limit in samples with a nonuniform doping density. By analyzing the current stream function in van der Pauw measurement geometry, it is shown that the electron density gradient can be quantitatively deduced from this LMA in the Drude regime. Results agree with gradients interpolated from local densities calibrated across an entire wafer, establishing a generalization of the van der Pauw method to quantify density gradients. Results will be shown of various semoconductor systems where this method is applied, from bulk doped semiconductors, to exfoliated 2D materials. McCormick Catalyst Award from Northwestern University, EECS Bridge Funding, and AFOSR FA9550-15-1-0247.